Impact of medical waste bin on contamination of patient's environment: an experimental study

BACKGROUND

Medical waste bins are potential source of microbial contamination in hospital environment, while there is no clear guidance for the management of them. We aimed to assess the impact of medical waste bins on patient's environment.

METHODS

This experimental study simulated microbial contamination by performing medical procedures on a patient model with fluorescent lotion. The waste bin was set as initially empty or two-thirds filled with waste, open or with a lid. The percentage of fluorescent contaminated area in designated patient's environments was analyzed by two independent observers.

RESULTS

Among a total of 120 experiments, the sides of the bins were more contaminated in open-occupied bins compared to open-empty bins and in open-occupied bins compared to lid-occupied bins (median 1.9175% vs. 0.0916% [P=0.001] and 1.9175% vs. 0.0899% [P=0.003], respectively). The top of bedside equipment trolley for preparing medical procedure was more contaminated in lid-occupied bins than open-occupied bins (median 0.0080% vs. 0.0040%, P=0.013).

DISCUSSION

In addition to reducing contamination of bin itself, the manually operated lid had potential risk of contributing microbial transmission by contaminating equipment trolley.

CONCLUSIONS

Medical waste bin should be kept no more than two-thirds full, and cautions should be taken when using manually operated lid, to avoid cross-contamination.

High-Volume Hospital Had Lower Mortality of Severe Intracerebral Hemorrhage Patients

Objective

Intracerebral hemorrhage (ICH) accompanies higher mortality rates than other type of stroke. This study aimed to investigate the association between hospital volume and mortality for cases of ICH.

Methods

We used nationwide data from 2013 to 2018 to compare high-volume hospitals (≥32 admissions/year) and low-volume hospitals (<32 admissions/year). We tracked patients' survival at 3-month, 1-year, 2-year, and 4-year endpoints. The survival of ICH patients was analyzed at 3-month, 1-year, 2-year, and 4-year endpoints using Kaplan-Meier survival analysis. Multivariable logistic regression analysis and Cox regression analysis were performed to determine predictive factors of poor outcomes at discharge and death.

Results

Among 9,086 ICH patients who admitted to hospital during 18-month period, 6,756 (74.4%) and 2,330 (25.6%) patients were admitted to high-volume and low-volume hospitals. The mortality of total ICH patients was 18.25%, 23.87%, 27.88%, and 35.74% at the 3-month, 1-year, 2-year, and 4-year, respectively. In multivariate logistic analysis, high-volume hospitals had lower poor functional outcome at discharge than low-volume hospitals (odds ratio, 0.80; 95% confidence interval, 0.72-0.91; p < 0.001). In the Cox analysis, high-volume hospitals had significantly lower 3-month, 1-year, 2-year, and 4-year mortality than low-volume hospitals (p < 0.05).

Conclusion

The poor outcome at discharge, short- and long-term mortality in ICH patients differed according to hospital volume. High-volume hospitals showed lower rates of mortality for ICH patients, particularly those with severe clinical status.

Lower-Body Fractures and the Risk of Dementia: A Nationwide Population-Based Study

BACKGROUND AND PURPOSE

The association between physical activity and dementia has been shown in various observational studies. We aimed to determine the risk of dementia in the elderly with lower-body fractures.

METHODS

We reconstructed a population-based matched cohort from the National Health Insurance Service-Senior Cohort data set that covers 511,953 recipients of medical insurance in South Korea.

RESULTS

Overall 53,776 subjects with lower-body fractures were identified during 2006-2012, and triplicate control groups were matched randomly by sex, age, and years from the index date for each subject with a fracture. There were 3,573 subjects (6.6%) with and 7,987 subjects (4.9%) without lower-body fractures who developed dementia from 2008 up to 2015. Lower-body fractures were independently associated with a subsequent dementia diagnosis with a higher adjusted hazard ratio (aHR) (1.55, 95% confidence interval [CI]=1.49-1.62) compared with upper-body fractures (aHR=1.19, 95% CI=1.14-1.23).

CONCLUSIONS

These results support the protective role of physical activity against dementia and highlight the importance of promoting fracture prevention in the elderly.

The First Report on the Complete Sequence Characterization of Bluetongue Virus Serotype 3 in the Republic of Korea

The bluetongue virus (BTV) is a significant animal pathogen with economic implications in the ruminant industry. Despite global reports on BTV detection and epidemiologic investigations, limited studies have focused on the virus in the ROK. In this study, BTV epidemiological research was conducted on blood samples from cattle and goat farms across nine regions during 2013-2014. The results showed that 3.33% of bovine blood samples (194/5824) and 0.19% of goat blood samples (2/1075) tested positive for BTV antibodies using ELISA. In Jeju-do, BTV RNA amplification occurred in 51 of 422 samples (12.1%) using real-time reverse transcription (RT-qPCR). The isolation of one sample revealed it as serotype 3, as indicated by the sequence of segments 2 (Seg-2) and 6 (Seg-6), associated with the eastern BTV topotype. However, based on Seg-1, -3, -4, -5, -7, -8, -9, and -10 analyses, the BTV-3/JJBB35 strain is more closely related to distinct BTV strains. These findings imply BTV circulation and that the Korean-isolated BTV might originate from Asian BTV strains due to multiple reassortment events. This study provides foundational data for ongoing BTV monitoring and disease-control policies in the ROK.

Propensity score matched analysis for the safety and effectiveness of remdesivir in COVID-19 patients with renal impairment

BACKGROUNDS

Remdesivir (RDV) is an antiviral agent approved for the treatment of coronavirus disease 2019 (COVID-19); however, is not recommended for patients with renal impairment. Due to limitations associated with prospective clinical trials, real-world data on the safety and efficacy of RDV in patients with renal impairment are necessary.

METHODS

Propensity score-matched (PSM) retrospective analysis was conducted between March 2020 and September 2022 in COVID-19 patients with an eGFR < 30 mL/min in four Korean hospitals. The RDV treatment group was matched to the untreated control group. The safety and clinical outcomes in patients who received RDV were analyzed.

RESULTS

A total of 564 patients were enrolled; 229 patients received RDV either for treatment or prophylaxis. On day 5, no difference in nephrotoxicity was observed between the two groups, and liver enzyme levels were within the normal range. In multivariate analysis for new dialysis, RDV treatment was not a risk factor for new dialysis. Among the 564 patients, 417 were indicated for a 5-day course of RDV treatment and 211 patients were treated with RDV. After PSM, no differences in the clinical outcomes were observed between the two groups.

CONCLUSION

RDV use in COVID-19 patients with renal impairment did not result in significant nephrotoxicity or hepatotoxicity.

A leptin-loaded poly-ϵ-caprolactone 3D printing scaffold for odontoblastic differentiation in human dental pulp cells

This study investigated the effects on odontoblast differentiation of a 3D-printed poly-ϵ-caprolactone (PCL) scaffold that incorporated leptin. Material extrusion-type 3D printing with a 43 000-molecular weight PCL material was used to fabricate a PCL scaffold with a 6 mm diameter, 1 mm height, and 270-340 µm pore size. The experimental groups were PCL scaffolds (control group), PCL scaffolds with aminated surfaces (group A), and PCL scaffolds with leptin on the aminated surface (group L). The aminated surface was treated with 1,6-hexanediamine and verified by ninhydrin analysis. Leptin loading was performed using Traut's reagent and 4-(N-Maleimidomethyl)cyclohexane-1-carboxylic acid 3-sulfo-N-hydroxysuccinimide ester sodium salt (Sulfo-SMCC). Groups A and L showed significantly higher surface wettability, pulp cell adhesion, and proliferation than the control group. Group L exhibited increased alkaline phosphatase, calcification deposits, and mRNA and protein expression of dentin sialophosphoprotein and dentin matrix acidic phosphoprotein 1 compared with the control group. In this study, a 3D-printed PCL scaffold containing leptin was enhanced odontoblast differentiation and dental pulp cells adhesion and proliferation.

Possibility of Decreasing Incidence of Human Immunodeficiency Virus Infection in Korea

BACKGROUND

The number of newly diagnosed cases of human immunodeficiency virus (HIV) infection in Korea, which had increased until 2019, has markedly decreased since the coronavirus disease 2019 pandemic started. This study evaluated whether the decrease is due to a reduction in the incidence of HIV infection and/or delayed diagnosis during the pandemic.

MATERIALS AND METHODS

We reviewed the medical records of 587 newly diagnosed patients with HIV infection between February 2018 and January 2022 from four general hospitals, and their characteristics were compared between the pre-pandemic and pandemic periods. The lapse time from infection to diagnosis was estimated using an HIV modeling tool.

RESULTS

The estimated mean times to diagnosis were 5.68 years (95% confidence interval [CI]: 4.45 - 6.51 years) and 5.41 years (95% CI: 4.09 - 7.03 years) before and during the pandemic, respectively (P = 0.016). The proportion of patients with acquired immunodeficiency syndrome-defining illnesses, expected to visit hospitals regardless of the pandemic, decreased from 17.2% before the pandemic to 11.9% during the pandemic (P = 0.086).

CONCLUSION

The decrease in the number of newly diagnosed cases of HIV infection in Korea might have resulted from an actual decrease in the incidence of HIV infection rather than a worsening of underdiagnosis or delayed diagnosis.

Prospero Homeobox 1 and Doublecortin Correlate with Neural Damage after Ischemic Stroke

Objective

Markers of neuroinflammation during ischemic stroke are well characterized, but additional markers of neural damage are lacking. The study identified associations of behavioral disorders after stroke with histologic neural damage and molecular biological change.

Methods

8-week-old, 25g male mice of the C57BL/6J strain were subjected to middle cerebral artery occlusion (MCAO) to induce ischemic stroke. The control group was a healthy wild type (WT), and the experimental group were designed as a low severity MCAO1 and a high severity MCAO2 based on post-stroke neurological scoring. All groups underwent behavioral tests, real-time polymerase chain reaction (rt-PCR), triphenyltetrazolium chloride (TTC) staining and hematoxylin and eosin (H&E) staining. One-way analysis of variance (ANOVA) was used to analyze statistical significance between groups.

Results

In TTC staining, MCAO1 showed 29.02% and MCAO2 showed 38.94% infarct volume (p<0.0001). The pro-inflammatory cytokine interleukin (IL)-1β was most highly expressed in MCAO2 (WT 0.44 vs MCAO1 2.69 vs MCAO2 5.02, p<0.0001). From the distance to target in the Barnes maze test, WT had a distance of 178 cm, MCAO1 had a distance of 276 cm, and MCAO2 had a distance of 1051 (p=0.0015). The latency to target was 13.3 seconds for WT, 27.9 seconds for MCAO1, and 87.9 seconds for MCAO2 (p=0.0007). Prospero homeobox 1 (Prox1) was most highly expressed in MCAO2 (p=0.0004). Doublecortin (Dcx) was most highly expressed in MCAO2 (p<0.0001).

Conclusion

The study demonstrated that histological damage to neural cells and changes in brain mRNA expression were associated with behavioral impairment after ischemic stroke. Prox1 and Dcx may be biomarkers of neural damage associated with long-term cognitive decline, and increased expression at the mRNA level was consistent with neural damage and long-term cognitive dysfunction.

Multiple reaction pathway on alkaline earth imide supported catalysts for efficient ammonia synthesis

The tunability of reaction pathways is required for exploring efficient and low cost catalysts for ammonia synthesis. There is an obstacle by the limitations arising from scaling relation for this purpose. Here, we demonstrate that the alkali earth imides (AeNH) combined with transition metal (TM = Fe, Co and Ni) catalysts can overcome this difficulty by utilizing functionalities arising from concerted role of active defects on the support surface and loaded transition metals. These catalysts enable ammonia production through multiple reaction pathways. The reaction rate of Co/SrNH is as high as 1686.7 mmol·gCo-1·h-1 and the TOFs reaches above 500 h-1 at 400 °C and 0.9 MPa, outperforming other reported Co-based catalysts as well as the benchmark Cs-Ru/MgO catalyst and industrial wüstite-based Fe catalyst under the same reaction conditions. Experimental and theoretical results show that the synergistic effect of nitrogen affinity of 3d TMs and in-situ formed NH2- vacancy of alkali earth imides regulate the reaction pathways of the ammonia production, resulting in distinct catalytic performance different from 3d TMs. It was thus demonstrated that the appropriate combination of metal and support is essential for controlling the reaction pathway and realizing highly active and low cost catalysts for ammonia synthesis.

Real-World Effectiveness of Nirmatrelvir-Ritonavir and Its Acceptability in High-Risk COVID-19 Patients

BACKGROUND

Nirmatrelvir-ritonavir is highly effective in preventing severe coronavirus disease 2019 (COVID-19) in high-risk patients with mild-to-moderate severity. However, real-world performance data are limited, and the drug is not so acceptable to the COVID-19 patients at high risk who need it in Korea.

METHODS

To evaluate the effectiveness of nirmatrelvir-ritonavir, we conducted a propensity score-matched retrospective cohort study on patients with mild-to-moderate COVID-19 at high risk for a severe disease who were hospitalized at four hospitals in South Korea from February 2022 to April 2022. A total of 236 patients in the treatment group (administered nirmatrelvir-ritonavir) and 236 in the matched control group (supportive care only) were analyzed for the primary outcome, i.e., the time to oxygen support-free survival. The secondary outcome was a composite result of disease progression. The reason for not prescribing nirmatrelvir-ritonavir to the indicated patients was also investigated.

RESULTS

The treatment group showed significantly longer oxygen support-free survival than the matched control group (adjusted hazard ratio [aHR], 0.07; 95% confidence interval [CI], 0.01-0.31; P < 0.001). Multivariate Cox regression analysis showed that age (aHR, 1.03; 95% CI, 1.00-1.07), National Early Warning Score-2 at admission (aHR, 1.36; 95% CI, 1.08-1.71), nirmatrelvir-ritonavir treatment, female sex (aHR, 0.37; 95% CI, 0.15-0.88), and time from symptom onset to admission (aHR, 0.67; 95% CI, 0.48-0.95) were significantly associated with oxygen therapy. However, none of the factors were related to the composite outcome. In the unmatched control group, 19.9% of 376 patients had documented explanations for nirmatrelvir-ritonavir non-prescription, and 44.0% of these were due to contraindication criteria. In the treatment group, 10.9% of patients discontinued the medication primarily because of adverse events (71.4%), with gastrointestinal symptoms being the most common (50.0%).

CONCLUSION

Nirmatrelvir-ritonavir treatment significantly reduced oxygen therapy requirements in high-risk patients with COVID-19 during the omicron variant surge in South Korea. Physicians are encouraged to consider the active use of nirmatrelvir-ritonavir and to be watchful for gastrointestinal symptoms during medication.

Resistance Trends of Antiretroviral Agents in People with Human Immunodeficiency Virus in Korea, 2012 - 2020

BACKGROUND

Domestic data on antiretroviral drug (ARV) resistance are limited, while alterations in ARV resistance are expected as the incidence of human immunodeficiency virus (HIV) infection increases. We evaluated the ten-year change in ARV resistance in people with HIV (PWH) in Korea.

MATERIALS AND METHODS

Adults aged ≥19 years and diagnosed with HIV infection between January 2010 and December 2020 at a 750-bed municipal hospital were retrospectively reviewed. Data on clinical characteristics and resistance mutation test results were collected. The study population was divided into three-year intervals according to diagnosed year and their clinical characteristics were compared.

RESULTS

A total of 248 PWH were analyzed, and ARV resistance was detected in 30 of them (12.1%). Resistance was detected most frequently in PWH aged ≤29 years (16, 6.5%), and the median percentage of resistance detection per year was 14.3% (interquartile range, 12.7 - 16.1). The trend of the overall prevalence of ARV resistance mutations slightly decreased and then increased over time (15.3% in 2012 - 2014, 9.6% in 2015 - 2017, and 12.9% in 2018 - 2020). The prevalence of the non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance markedly decreased over time (15.3% in 2012 - 2014, 8.7% in 2015 - 2017, and 2.4% in 2018-2020), while that of protease inhibitor (PI) and integrase strand transfer inhibitor (INSTI) increased from 0 until 2018 to 3.5% and 8.2% in 2018 - 2020, respectively.

CONCLUSION

The trend of NNRTI resistance has decreased over time, and resistance to PIs and INSTIs increased from 2018. Therefore, continuous monitoring of ARV resistance pattern is necessary.

Reinforcing Synaptic Plasticity of Defect-Tolerant States in Alloyed 2D Artificial Transistors

While two-dimensional (2D) materials possess the desirable future of neuromorphic computing platforms, unstable charging and de-trapping processes, which are inherited from uncontrollable states, such as the interface trap between nanocrystals and dielectric layers, can deteriorate the synaptic plasticity in field-effect transistors. Here, we report a facile and effective strategy to promote artificial synaptic devices by providing physical doping in 2D transition-metal dichalcogenide nanomaterials. Our experiments demonstrate that the introduction of niobium (Nb) into 2D WSe2 nanomaterials produces charge trap levels in the band gap and retards the decay of the trapped charges, thereby accelerating the artificial synaptic plasticity by encouraging improved short-/long-term plasticity, increased multilevel states, lower power consumption, and better symmetry and asymmetry ratios. Density functional theory calculations also proved that the addition of Nb to 2D WSe2 generates defect tolerance levels, thereby governing the charging and de-trapping mechanisms of the synaptic devices. Physically doped electronic synapses are expected to be a promising strategy for the development of bioinspired artificial electronic devices.

Risk of microbial transmission by reusing gloves after alcohol-based hand hygiene

BACKGROUND

Disinfection of gloves might reduce the the workload of healthcare workers, protect the environment, and bring economic benefits. Thus, the safety of hand hygiene of gloved hands is an important issue.

AIM

We aimed to evaluate the risk of microbial transmission by comparing residual microorganisms after multiple patient contacts, with or without gloves, in clinical practice.

METHODS

Researchers, two with gloved hands (single or double gloves) and one with bare hands, made rounds of patients, followed by alcohol-based hand rub. Hand imprints were obtained before and after the rounds and cultured. The number of colony-forming units (CFUs) of gloved and bare hands was compared, and the colony distribution was evaluated semi-quantitatively by hand region.

FINDINGS AND CONCLUSION

A total of 108 imprints were obtained after 10 rounds. The median CFU counts were significantly higher in the gloved hands (single and double) than in the bare hands (9.00 vs. 3.50, p=0.028). The CFU counts of single- and double-gloved hands were higher after than before contact (p=0.044 and p=0.001, respectively). Carbapenem-resistant Acinetobacter baumannii was identified in a pair of double gloves after a round, which included patients with the same organism with identical antibiotic susceptibility results. The mean percentage of colony-growing compartments from gloved hands was significantly higher than that of bare hands in the finger and wrist regions (p=0.019 and p=0.049, respectively). Compared to bare hands, reuse of gloves increased residual microbial colonies and potential for transmission of multidrug-resistant organisms, even after using alcohol-based hand rub.

Fermented Soybean Paste Attenuates Biogenic Amine-Induced Liver Damage in Obese Mice

Biogenic amines are cellular components produced by the decarboxylation of amino acids; however, excessive biogenic amine production causes adverse health problems. The relationship between hepatic damage and biogenic amine levels in nonalcoholic fatty liver disease (NAFLD) remains unclear. In this study, mice were fed a high-fat diet (HFD) for 10 weeks to induce obesity, presenting early-stage of NAFLD. We administered histamine (20 mg/kg) + tyramine (100 mg/kg) via oral gavage for 6 days to mice with HFD-induced early-stage NAFLD. The results showed that combined histamine and tyramine administration increased cleaved PARP-1 and IL-1β in the liver, as well as MAO-A, total MAO, CRP, and AST/ALT levels. In contrast, the survival rate decreased in HFD-induced NAFLD mice. Treatment with manufactured or traditional fermented soybean paste decreased biogenically elevated hepatic cleaved PARP-1 and IL-1β expression and blood plasma MAO-A, CRP, and AST/ALT levels in HFD-induced NAFLD mice. Additionally, the biogenic amine-induced reduction in survival rate was alleviated by fermented soybean paste in HFD-induced NAFLD mice. These results show that biogenic amine-induced liver damage can be exacerbated by obesity and may adversely affect life conservation. However, fermented soybean paste can reduce biogenic amine-induced liver damage in NAFLD mice. These results suggest a beneficial effect of fermented soybean paste on biogenic amine-induced liver damage and provide a new research perspective on the relationship between biogenic amines and obesity.

Short-Term Effectiveness of Oral Nirmatrelvir/Ritonavir Against the SARS-CoV-2 Omicron Variant and Culture-Positive Viral Shedding

BACKGROUND

Information on the effectiveness of nirmatrelvir/ritonavir against the omicron is limited. The clinical response and viral kinetics to therapy in the real world need to be evaluated.

METHODS

Mild to moderate coronavirus disease 2019 (COVID-19) patients with risk factors for severe illness were prospectively enrolled as a treatment group with nirmatrelvir/ritonavir therapy versus a control group with supportive care. Serial viral load and culture from the upper respiratory tract were evaluated for seven days, and clinical responses and adverse reactions were evaluated for 28 days.

RESULTS

A total of 51 patients were analyzed including 40 in the treatment group and 11 in the control group. Faster symptom resolution during hospitalization (P = 0.048) was observed in the treatment group. Only minor adverse reactions were reported in 27.5% of patients. The viral load on Day 7 was lower in the treatment group (P = 0.002). The viral culture showed a positivity of 67.6% (25/37) vs. 100% (6/6) on Day 1, 0% (0/37) vs. 16.7 (1/6) on Day 5, and 0% (0/16) vs. 50.0% (2/4) on Day 7 in the treatment and control groups, respectively.

CONCLUSIONS

Nirmatrelvir/ritonavir against the omicron was safe and resulted in negative viral culture conversion after Day 5 of treatment with better symptomatic resolution.

The Impact of Particle Size and Surface Treatment of Zirconia Suspension for Photocuring Additive Manufacturing

To prepare a photocurable ceramic suspension for use in commercialized additive manufacturing equipment, the effects of the rheological properties of zirconia particles added to a binder, and the presence or absence of a silane coupling agent on the particles was evaluated. To this end, three experimental groups (ZSs, ZMs, ZLs) and three control groups (ZS, ZM, ZL) were designed depending on the size of the underlying zirconia particles. The test-group zirconia suspensions were prepared through silanization, which was not applied to the control-group suspensions. Depending on the particle size, viscosity differences between the test and control groups were 16,842, 18,623, and 12,303 mPa·s, respectively. Compared to the other groups, the viscosity of the ZLs group suspension decreased by 70.98-88.04%. This confirmed that the viscosity of the suspensions was affected by the particle size and the presence of silane coating. The dispersion stability of the zirconia suspensions was evaluated over 20 days. A sedimentation test confirmed that the sedimentation rate of the ZLs group was slower than those of the other groups. This study aimed to optimize the suspension manufacturing method to effectively be utilized in further commercializing zirconia three-dimensional (3D) printing and could also help to develop various medical applications.

Low humoral and cellular immune responses early after breakthrough infection may contribute to severe COVID-19

Background

Little is known about the immune determinants for severe coronavirus disease 2019 (COVID-19) in individuals vaccinated against severe acute respiratory syndrome coronavirus 2. We therefore attempted to identify differences in humoral and cellular immune responses between patients with non-severe and severe breakthrough COVID-19.

Methods

We prospectively enrolled hospitalized patients with breakthrough COVID-19 (severe and non-severe groups) and uninfected individuals who were vaccinated at a similar time (control group). Severe cases were defined as those who required oxygen therapy while hospitalized. Enzyme-linked immunosorbent assays and flow cytometry were used to evaluate humoral and cellular immune responses, respectively.

Results

Anti-S1 IgG titers were significantly lower in the severe group than in the non-severe group within 1 week of symptom onset and higher in the non-severe group than in the control group. Compared with the control group, the cellular immune response tended to be diminished in breakthrough cases, particularly in the severe group. In multivariate analysis, advanced age and low anti-S1 IgG titer were associated with severe breakthrough COVID-19.

Conclusions

Severe breakthrough COVID-19 might be attributed by low humoral and cellular immune responses early after infection. In the vaccinated population, delayed humoral and cellular immune responses may contribute to severe breakthrough COVID-19.

Effects of UV Absorber on Zirconia Fabricated with Digital Light Processing Additive Manufacturing

This study evaluated the effect of UV absorbers on the dimensional accuracy of zirconia specimens fabricated by additive manufacturing using a digital light process. Zirconia suspension for additive manufacturing was prepared by setting the volume fractions (0, 0.005, 0.05, and 0.1%) of various UV absorbers. The effect of UV absorber content was evaluated through curing thickness, geometric overgrowth model design, linear deviation, and microstructure evaluation before and after sintering. Statistical analysis was performed by Kruskal-Wallis H and post-tested by the Bonferroni correction method. There was no significant difference in the cure depth according to the presence or absence of the UV absorber, the difference in geometric overgrowth was from 2.1 to 12.5%, and the overgrowth significantly decreased as the amount of added UV absorber increased. This result may contribute to improved precision of 3D multilayer ceramic products.

Development of new tools to study membrane-anchored mammalian Atg8 proteins

ABBREVIATIONS

A:C autophagic membrane:cytosol; ALS amyotrophic lateral sclerosis; ATG4 autophagy related 4; Atg8 autophagy related 8; BafA1 bafilomycin A₁; BNIP3L/Nix BCL2 interacting protein 3 like; CALCOCO2/NDP52 calcium binding and coiled-coil domain 2; EBSS Earle's balanced salt solution; GABARAP GABA type A receptor-associated protein; GST glutathione S transferase; HKO hexa knockout; K_d dissociation constant; LIR LC3-interacting region; MAP1LC3/LC3 microtubule associated protein 1 light chain 3; NLS nuclear localization signal/sequence; PE phosphatidylethanolamine; SpHfl1 Schizosaccharomyces pombeorganic solute transmembrane transporter; SQSTM1/p62 SQSTM1/p62; TARDBP/TDP-43 TAR DNA binding protein; TKO triple knockout.

Pharmacological Treatment for Neuroinflammation in Stress-Related Disorder

Stress is an organism’s response to a biological or psychological stressor, a method of responding to threats. The autonomic nervous system and hypothalamic–pituitary–adrenal axis (HPA axis) regulate adaptation to acute stress and secrete hormones and excitatory amino acids. This process can induce excessive inflammatory reactions to the central nervous system (CNS) by HPA axis, glutamate, renin-angiotensin system (RAS) etc., under persistent stress conditions, resulting in neuroinflammation. Therefore, in order to treat stress-related neuroinflammation, the improvement effects of several mechanisms of receptor antagonist and pharmacological anti-inflammation treatment were studied. The N-methyl-D-aspartate (NMDA) receptor antagonist, peroxisome proliferator-activated receptor agonist, angiotensin-converting enzyme inhibitor etc., effectively improved neuroinflammation. The interesting fact is that not only can direct anti-inflammation treatment improve neuroinflammation, but so can stress reduction or pharmacological antidepressants. The antidepressant treatments, including selective serotonin reuptake inhibitors (SSRI), also helped improve stress-related neuroinflammation. It presents the direction of future development of stress-related neuroinflammation drugs. Therefore, in this review, the mechanism of stress-related neuroinflammation and pharmacological treatment candidates for it were reviewed. In addition, treatment candidates that have not yet been verified but indicate possibilities were also reviewed.

Pattern of pericardial calcification determines the mid-term postoperative outcome after pericardiectomy in chronic constrictive pericarditis

Background/Introduction

Although pericardiectomy is an effective treatment of constrictive pericarditis (CP), clinical outcome is not always successful. Pericardial calcification is a unique finding in CP. However, the amount and localization of calcification vary. Computer tomography (CT) can visualize the pericardial calcification with high sensitivity and provide the anatomical assessment.

Purpose

We investigated that how the pattern and amount of pericardial calcification affect the mid-term postoperative outcome after pericardiectomy in CP.

Methods

All of the patients who underwent total pericardiectomy in our hospital from 2010 to 2020 were derived from electrical medical records (n=105). Among them, preoperative CT scans (non-gated non-contrast) of 98 patients were available and, thus, 98 consecutive patients were finally analyzed. Medical records were reviewed in a retrospective manner. Cardiovascular event is defined as cardiovascular death or hospitalization associated with a heart failure symptom and all cause event is defined as all events that require admission. CT scan was analyzed by Aquarius Workstation, and the volume and localization pattern of pericalcification were derived. Pericardium calcium score was given as an Agatston score.

Results

Of 98 patients, 25 (25.5%) patients were hospitalized with heart failure symptom after pericardiectomy. Median follow up duration of patients is 172 weeks. A group with cardiovascular event had higher NYHA grade (P&lt;0.001), lower calcium volume (P=0.004), and lower calcium score (P=0.01). Multivariate cox proportional analysis showed that high ln(calcium score) before pericardiectomy was dependent predictor of cardiovascular event (hazard ratio, 0.90; P=0.04) and all cause event (hazard ratio, 0.91, P=0.04) after pericardiectomy. When we set the cut off value at 7.22, based on ROC curve, there was a significant difference in cardiovascular event between the groups divided by this cutoff value in Kaplan-Meier curve (P=0.002) and multivariate cox proportional analysis (P=0.04). In the subgroup analysis, myocardium invasion and circumferential calcification were more common in the high calcium score group. Idiopathic & tuberculosis pericarditis were more associated with high calcium score group and post-operative pericarditis, other reasons (infection, radiation, etc) were more associated with low calcium group.

Conclusion

Low burden of pericardial calcification was associated high rate of mid-term clinical event after pericardiectomy CP. Preoperative evaluation of pericardial calcification pattern can be used as predictor of postoperative outcomes.

Funding Acknowledgement

Type of funding sources: None.

PCSK9 modulates the Wnt/beta-catenin signaling pathway in myocardial ischemia/reperfusion injury

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protein that affects cholesterol homeostasis. Recent research has found that PCSK9 has various effects on the heart that are unrelated to LDL cholesterol regulation. The Wnt/β-catenin signaling pathway plays a crucial role during heart development, and it is re-activated in response to cardiac injury. Low-density lipoprotein receptor-related proteins 5 (LRP5) act as co-receptors of Wnt ligands and are indispensable for Wnt/β-catenin signal transduction. However, it is not fully elucidated whether other members of the LDLR-superfamily may be targets of PCSK9.

Purpose

This study aimed to determine if LRP5 is a PCSK9 target, study the association between PCSK9 and Wnt/β-catenin signaling, and elucidate its effect on myocardial infarction in patients with ischemic cardiomyopathy.

Methods

The expression of Lrp5, phospho-β-catenin, total β-catenin was evaluated by western blot analysis, and the effects of overexpressed PCSK9 were tested under normoxia, hypoxia, or hypoxia/re-oxygenation (H/R) in mouse cardiomyocytes (HL-1). The transcriptional activity of β-catenin was assessed using the TOP-Flash/FOP-Flash luciferase reporter assay. In addition, the impact on various downstream targets of the Wnt/β-catenin signaling pathway was assessed using a quantitative real-time polymerase chain reaction. To examine whether PCSK9 regulates injury of cardiomyocytes in vivo, we subjected transgenic mice with cardiac-specific overexpression of PCSK9 (PCSK9 TG) and wild-type (WT) mice to either sham surgery or ischemia/reperfusion (I/R) surgery.

Results

Under hypoxic conditions, the Wnt/β-catenin signaling pathway-related genes were downregulated in HL-1 cells, as evidenced by lower Lrp5 and active phospho-β-catenin expression levels (0.5-fold, n=3, p&lt;0.01). After H/R, the Wnt/β-catenin-related genes were recovered (1.5-fold, p&lt;0.01) in the control group but not in the PCSK9 overexpressed group. In the luciferase reporter assay results, PCSK9 overexpression inhibited the recovery of β-catenin transcriptional activity after H/R, in contrast to the control group. Furthermore, mRNA levels of Axin2, Cyclin D1, which are the Wnt/β-catenin signaling downstream pathway targets, were down-regulated under hypoxia and recovered after H/R but did not recover in PCSK9 overexpressed cells. In the mouse I/R model, the overall protein levels of the Wnt/β-catenin signaling-related genes were down-regulated in PCSK9 TG mice compared to WT mice after I/R injury.

Conclusions

These results indicated that the regulation of PCSK9 is closely associated with the Wnt/β-catenin signaling pathway which may play a crucial role in damaged cardiomyocytes. It suggests that the regulation of PCSK9 could be a therapeutic target in patients with ischemic cardiomyopathy.

Funding Acknowledgement

Type of funding sources: None.

Intravascular ultrasound-guided optimization for chronic total occlusion-percutaneous coronary intervention with multiple drug-eluting stents

Background

Multiple stenting in the chronic total occlusion (CTO) lesions is frequently required, however associated with poorer clinical outcomes. It is demonstrated that intravascular ultrasound (IVUS)-guided CTO-percutaneous coronary intervention (PCI) is related to a lower risk of adverse clinical events.

Purpose

We aimed to evaluate the clinical impact of stent optimization under IVUS guidance for multiple stenting, comparing with single stenting.

Methods

A total of 916 patients receiving drug-eluting stent (DES) under IVUS guidance were classified into two groups (stent optimization and non-optimization) according to optimization criteria (an absolute expansion criteria; minimal stent area ≥4.9 mm2 and a relative expansion criteria; 80% of mean reference lumen area). Of total population, 314 patients (34.3%) were treated with single stent and 575 patients (62.7%) were treated with multiple stents, respectively. Ischemic-driven target-lesion revascularization (TLR)/reocclusion was evaluated.

Results

Under IVUS guidance, 316 patients (34.5%) met IVUS criteria for stent optimization The achieving rates were 53% in the single stent group and 24% in the multiple stents group, respectively, (p&lt;0.001). During a median of 4.7 years, the multiple stent group showed a significantly higher TLR/reocclusion rate, compared with the single stent group (12.8% vs. 5.2%, adjusted hazard ratio [HR] 2.51, 95% confidence interval [CI] 1.20–5.25, p=0.01). (Figure 1) Meeting both the absolute and relative expansion criteria was associated with a significantly low rate of TLR/reocclusion rate (12.5% vs. 5.2%, adjusted HR 0.34, 95% CI: 0.15–0.79, p=0.01). Under IVUS-guidance, there was no significant difference between multiple stenting and single stenting in case of achieving the optimization criteria (6.5% vs. 4.2%, p=0.11), whereas non-optimization group in the patients with multiple stenting showed a significantly higher rate of TLR/reocclusion, compared with IVUS-optimization group in the patients with single stenting (14.5% vs. 4.2%, p=0.002). (Figure 2)

Conclusions

In CTO-PCI with DES, multiple stenting significantly increased the risk of TLR/reocclusion. IVUS-guided optimization for multiple stenting showed a comparable long-term risk of TLR/reocclusion to single stenting with IVUS optimization. Hence, achieving IVUS expansion criteria may help to reduce the risk of TLR/reocclusion in CTO-PCI with multiple DES overlapping.

Funding Acknowledgement

Type of funding sources: None.

Risk calculator to predict 30-day mortality in left-sided infective endocarditis. The EURO-ENDO score

Background/Introduction

Infective endocarditis (IE) is associated with high in-hospital mortality, despite improvements in therapeutic strategies. Nonetheless, there is no prospective risk model to estimate IE mortality.

Purpose

We sought to develop and validate a calculator to predict 30-day mortality risk regarding to perform surgery or medical treatment alone in left-sided IE.

Methods

This is a prospective, multicenter registry that included patients between January 2016 and March 2018 with a diagnosis of IE based on ESC 2015 diagnostic criteria. Patients with possible or definite left-sided IE were included in the analyses. Clinical, biological, microbiological and imaging data were collected. The primary end point was 30-day mortality in patients with left-sided IE. The risk calculator was based on multivariable Cox regression models. The accuracy of the logistic regression models was assessed by discrimination and calibration using C-statistic and Hosmer-Lemeshow test.

Results

Among 3116 patients included, 2171 patients presented left-sided IE and 257 patients (11.8%) died during the first 30 days of IE diagnosis. After multivariable Logistic regression analysis, eleven variables were associated with 30-days mortality and were included in the calculator: previous cardiac surgery, previous stroke/TIA, creatinine &gt;2 mg/dL, S. aureus infection, embolic events on admission, heart failure or cardiogenic shock, vegetation size &gt;14 mm, presence of abscess, severe regurgitation, double left-sided IE and no left valve surgery. There was an excellent correlation between the predicted 30-days mortality in both models with or without performing left valve surgery (area under the receiver operator curve: 0.798 and 0.758, respectively). Moreover, calibration by Hosmer-Lemeshow were 0.085 and 0.09, respectively).

Conclusion(s)

Our risk score in patients with left-sided IE provides an accurate individualized estimation of 30-day mortality according to perform or not perform left-valve surgery. It allows medical professionals to determine whether submitting patients to surgery or not, and thus improve their prognosis.

Funding Acknowledgement

Type of funding sources: None.

Role of combined exercise stress echocardiography and cardiopulmonary exercise test in chronic thromboembolic disease

Background

Chronic thromboembolic pulmonary disease (CTEPD) without pulmonary hypertension could cause significant exercise limitations. However, interventional or surgical treatments for CTEPD with mild pulmonary hypertension or normal pressure are on controversy.

Purpose

We aimed to evaluate cardiopulmonary function through cardiopulmonary exercise test (CPET) with stress echocardiography and to determine whether exercise pulmonary hypertension can explain exercise limitations in CTEPD patients with mPAP &lt;30mmHg.

Methods

Patients diagnosed as CTEPD with mPAP less than 30mmHg was derived from our pulmonary hypertension center registry from April 2014 to October 2021.Transthoracic echocardiography (TTE) was performed at baseline (resting state) and immediately after CPET. TTE derived parameters and CPET parameters were compared with hemodynamic parameters measured by right catheterization.

Results

Total 37 patients were enrolled. Of these, Thirty-five patients had previously been diagnosed with CTEPH and had undergone PEA, BPA, or both. Most of the patients complained dyspnea of WHO functional class II or III. Pulmonary vascular resistance (PVR) was slightly higher than normal (185.0±102.2 dyne sec cm–5). Also VO2max was decreased in CPET (23.1±6.5 mL/kg/min). In correlation analysis, the higher the mPAP and PVR at rest, the lower VO2max during exercise. Meanwhile basal right ventricular (RV) function was normal, an increase in RVSP was notably observed during exercise (RVSP: pre-exercise 36.2±11.9, post-exercise 60.7±19.3, p value &lt;0.001). Furthermore RV function deteriorated during exercise (TAPSE: pre-exercise 16.1±4.8, post-exercise 12.9±5.0, p value &lt;0.001).

Conclusions

CTEPD patients with mild or normal PAP showed limited exercise capacity with exercise induced hypertension. Even in the mPAP less than 30mmHg, PVR and mPAP was significantly associated with exercise capacity. CPET with stress echocardiography could help to identify the main cause of exercise limitation in CTEPD patients and possibly provide the guideline for treatment plan.

Funding Acknowledgement

Type of funding sources: None.

Machine learning-based automatic estimation of cortical atrophy using brain computed tomography images

Cortical atrophy is measured clinically according to established visual rating scales based on magnetic resonance imaging (MRI). Although brain MRI is the primary imaging marker for neurodegeneration, computed tomography (CT) is also widely used for the early detection and diagnosis of dementia. However, they are seldom investigated. Therefore, we developed a machine learning algorithm for the automatic estimation of cortical atrophy on brain CT. Brain CT images (259 Alzheimer’s dementia and 55 cognitively normal subjects) were visually rated by three neurologists and used for training. We constructed an algorithm by combining the convolutional neural network and regularized logistic regression (RLR). Model performance was then compared with that of neurologists, and feature importance was measured. RLR provided fast and reliable automatic estimations of frontal atrophy (75.2% accuracy, 93.6% sensitivity, 67.2% specificity, and 0.87 area under the curve [AUC]), posterior atrophy (79.6% accuracy, 87.2% sensitivity, 75.9% specificity, and 0.88 AUC), right medial temporal atrophy (81.2% accuracy, 84.7% sensitivity, 79.6% specificity, and 0.88 AUC), and left medial temporal atrophy (77.7% accuracy, 91.1% sensitivity, 72.3% specificity, and 0.90 AUC). We concluded that RLR-based automatic estimation of brain CT provided a comprehensive rating of atrophy that can potentially support physicians in real clinical settings.

Change of mortality of patients with acute ischemic stroke before and after 2015

Introduction

Advances in the diagnosis and management of acute ischemic stroke (AIS) and the increased use of mechanical thrombectomy (MT) have improved the quality of care and prognosis of patients with AIS since 2015. We investigated the changing trends in mortality of patients with AIS in Korea before and after 2015.

Materials and methods

A retrospective cohort study was conducted using combined anonymized data from the Acute Stroke Assessment Registry of Korea and the Health Insurance Review & Assessment Service database. Patients with ischemic stroke with precise onset time and initial National Institute of Health Stroke Scale records were included.

Results

Patients receiving MT treatment increased from 256 (2.7%) pre-2015 to 1,037 (3.9%) post-2015 (p < 0.001). Overall mortality significantly decreased from pre-2015 to post-2015. In pre-2015, intravenous thrombolysis (IVT) administered within 2 h significantly reduced 3-month mortality when compared with non-IVT. While, in post-2015, IVT administered within 2 h significantly reduced the 3-month, 1-year, 2-year, and 4-year mortality (p < 0.05). MT only reduced 1-year mortality pre-2015; however, MT significantly reduced the 3-month, 1-year, and 2-year mortality post-2015 (p < 0.05). Post-stroke antiplatelet and anticoagulant drugs significantly reduced the 3-month, 1-year, 2-year, and 4-year mortality post-2015.

Discussion

Since 2015, faster IVT has significantly reduced the short- and long-term mortality in patients with AIS; MT reduced the 3-month, 1-year, and 2-year mortality. Post-stroke antithrombotic medication has significantly lowered the 2- and 4-year mortality since 2015.

Conclusions

Changing trends in AIS management since 2015 have improved the prognosis of patients with AIS.

Breakthrough COVID-19 Infection During the Delta Variant Dominant Period: Individualized Care Based on Vaccination Status Is Needed

BACKGROUND

The clinical features of coronavirus disease 2019 (COVID-19) patients in the COVID-19 vaccination era need to be clarified because breakthrough infection after vaccination is not uncommon.

METHODS

We retrospectively analyzed hospitalized COVID-19 patients during a delta variant-dominant period 6 months after the national COVID-19 vaccination rollout. The clinical characteristics and risk factors for severe progression were assessed and subclassified according to vaccination status.

RESULTS

A total of 438 COVID-19 patients were included; the numbers of patients in the unvaccinated, partially vaccinated and fully vaccinated groups were 188 (42.9%), 117 (26.7%) and 133 (30.4%), respectively. The vaccinated group was older, less symptomatic and had a higher Charlson comorbidity index at presentation. The proportions of patients who experienced severe progression in the unvaccinated and fully vaccinated groups were 20.3% (31/153) and 10.8% (13/120), respectively. Older age, diabetes mellitus, solid cancer, elevated levels of lactate dehydrogenase and chest X-ray abnormalities were associated with severe progression, and the vaccination at least once was the only protective factor for severe progression. Chest X-ray abnormalities at presentation were the only predictor for severe progression among fully vaccinated patients.

CONCLUSION

In the hospitalized setting, vaccinated and unvaccinated COVID-19 patients showed different clinical features and risk of oxygen demand despite a relatively high proportion of patients in the two groups. Vaccination needs to be assessed as an initial checkpoint, and chest X-ray may be helpful for predicting severe progression in vaccinated patients.

Short- and long-term mortality of subarachnoid hemorrhage according to hospital volume and severity using a nationwide multicenter registry study

Introduction

Recent improvements in treatment for subarachnoid hemorrhage (SAH) have decreased the mortality rates; however, the outcomes of SAH management are dependent on many other factors. In this study, we used nationwide, large-scale, observational data to investigate short- and long-term mortality rates after SAH treatment and the influence of patient severity and hospital volume.

Patients and methods

We selected patients with SAH treated with clipping and coiling from the South Korean Acute Stroke Assessment Registry. High- and low-volume hospitals performed ≥20 clipping and coiling procedures and <20 clipping and coiling procedures per year, respectively. Short- and long-term mortality were tracked using data from the Health Insurance Review and Assessment Service.

Results

Among 2,634 patients treated using clipping and coiling, 1,544 (58.6%) and 1,090 (41.4%) were hospitalized in high- and low-volume hospitals, respectively, and 910 (34.5%) and 1,724 (65.5%) were treated with clipping and coiling, respectively. Mortality rates were 13.5, 14.4, 15.2, and 16.1% at 3 months, 1, 2, and 4 years, respectively. High-volume hospitals had a significantly lower 3-month mortality rate. Patients with mild clinical status had a significantly lower 3-month mortality rate in high-volume hospitals than in low-volume hospitals. Patients with severe clinical status had significantly lower 1- and 2-year mortality rates in high-volume hospitals than in low-volume hospitals.

Conclusion

Short- and long-term mortality in patients with SAH differed according to hospital volume. In the modern endovascular era, clipping and coiling can lead to better outcomes in facilities with high stroke-care capabilities.

Utility of Exosomes in Ischemic and Hemorrhagic Stroke Diagnosis and Treatment

Stroke is the leading cause of death and neurological disorders worldwide. However, diagnostic techniques and treatments for stroke patients are still limited for certain types of stroke. Intensive research has been conducted so far to find suitable diagnostic techniques and treatments, but so far there has been no success. In recent years, various studies have drawn much attention to the clinical value of utilizing the mechanism of exosomes, low toxicity, biodegradability, and the ability to cross the blood–brain barrier. Recent studies have been reported on the use of biomarkers and protective and recovery effects of exosomes derived from stem cells or various cells in the diagnostic stage after stroke. This review focuses on publications describing changes in diagnostic biomarkers of exosomes following various strokes and processes for various potential applications as therapeutics.

Clinical Characteristics of COVID-19: Use of Steroids in Mostly Unvaccinated COVID-19 Patients Before the Omicron Variant

BACKGROUND

Glucocorticoids are one of the current standard agents for moderate to severe coronavirus disease 2019 (COVID-19) treatment based on the RECOVERY trial. Data on the real clinical application of steroids for COVID-19 are scarce and will help guide the optimal use of steroids. We described the current prescription pattern of steroids for COVID-19 and investigated the factors related to specific practices.

METHODS

All adults aged ≥ 19 years who were diagnosed with COVID-19 by real-time reverse transcription-polymerase chain reaction and admitted to one of 3 study hospitals from 8 December 2020 to 30 June 2021 were enrolled. Demographic and clinical data, including medications and oxygen therapy, were retrospectively collected from electronic medical records. The severity of comorbidities and COVID-19 were measured. The subjects were divided into steroid and nonsteroid groups, and the steroid group was then subdivided into standard and higher/longer groups.

RESULTS

Among a total of 805 patients, 217 (27.0%) were treated with steroids. The steroid group showed a higher rate of oxygen therapy (81.1% vs. 2.7%), more concomitant use of remdesivir (77.4% vs. 1.4%) or antibiotics (79.3% vs. 4.3%), and a higher proportion of high risk according to National Early Warning Score-2 score (30.0% vs. 0.9%) or severe risk according to National Institute of Allergy and Infectious Disease Ordinal Scale score (81.1% vs. 2.7%) than the nonsteroid group. The mortality of the steroid group was 4.6%. In the steroid group, 82.5% received a standard or lower dose of steroids within ten days, and 17.5% (38/217) received a higher or longer dose of steroids. Multivariate analysis showed that initial lymphopenia (adjusted odds ratio [aOR], 0.94; 95% confidence interval [CI], 0.89-0.99) and high level of lactate dehydrogenase (LDH) (aOR, 1.00; 95% CI, 1.00-1.01) were independent risk factors for higher doses or longer steroid use.

CONCLUSION

The dose and duration of steroids were in line with current guidelines in 82.5% of COVID-19 patients, but the outliers may need tailored therapy according to surrogate markers, such as initial lymphopenia or high level of LDH.

Genome-Scale Profiling and High-Throughput Analyses Unravel the Genetic Basis of Arsenic Content Variation in Rice

Ionomics, the study of the composition of mineral nutrients and trace elements in organisms that represent the inorganic component of cells and tissues, has been widely studied to explore to unravel the molecular mechanism regulating the elemental composition of plants. However, the genetic factors of rice subspecies in the interaction between arsenic and functional ions have not yet been explained. Here, the correlation between As and eight essential ions in a rice core collection was analyzed, taking into account growing condition and genetic factors. The results demonstrated that the correlation between As and essential ions was affected by genetic factors and growing condition, but it was confirmed that the genetic factor was slightly larger with the heritability for arsenic content at 53%. In particular, the cluster coefficient of japonica (0.428) was larger than that of indica (0.414) in the co-expression network analysis for 23 arsenic genes, and it was confirmed that the distance between genes involved in As induction and detoxification of japonica was far than that of indica. These findings provide evidence that japonica populations could accumulate more As than indica populations. In addition, the cis-eQTLs of AIR2 (arsenic-induced RING finger protein) were isolated through transcriptome-wide association studies, and it was confirmed that AIR2 expression levels of indica were lower than those of japonica. This was consistent with the functional haplotype results for the genome sequence of AIR2, and finally, eight rice varieties with low AIR2 expression and arsenic content were selected. In addition, As-related QTLs were identified on chromosomes 5 and 6 under flooded and intermittently flooded conditions through genome-scale profiling. Taken together, these results might assist in developing markers and breeding plans to reduce toxic element content and breeding high-quality rice varieties in future.

Unique Conduction Band Minimum of Semiconductors Possessing a Zincblende-Type Framework

Tetrahedral semiconductors such as Si adopt a diamond-type crystal structure with low packing density arising from open cavities in the crystallographic space. By taking LiAlGe as an example, we propose a zincblende-type framework as a platform for semiconductors possessing electroactive cavities. LiAlGe adopts a half-Heusler-type crystal structure including an ordered diamond-type sublattice (zincblende-type) (AlGe) and is an indirect semiconductor with a band gap of ∼0.1 eV. The conduction band minimum (CBM) is uniquely located at the cavity space surrounded by four cations (Al₄) in real space. The bond ionicity and cation (Al) p orbitals located around the Fermi energy are requisite for the CBM to float in the cavity space. DFT calculations indicate the conversion of the semiconductor to a semimetallic electride under a pressure of ∼8 GPa, which is accompanied by band gap collapse due to electron transfer from valence band maximum to the cavity space. The high-pressure electride of LiAlGe formed under a very small critical pressure is derived from the presence of inherent crystallographic cavities having deep orbital levels energetically. This finding suggests the possible utilization of electroactive cavity spaces in tetrahedral semiconductors, which are widely used in modern electronic devices.

ROCK and PDE-5 Inhibitors for the Treatment of Dementia: Literature Review and Meta-Analysis

Dementia is a disease in which memory, thought, and behavior-related disorders progress gradually due to brain damage caused by injury or disease. It is mainly caused by Alzheimer’s disease or vascular dementia and several other risk factors, including genetic factors. It is difficult to treat as its incidence continues to increase worldwide. Many studies have been performed concerning the treatment of this condition. Rho-associated kinase (ROCK) and phosphodiesterase-5 (PDE-5) are attracting attention as pharmacological treatments to improve the symptoms. This review discusses how ROCK and PDE-5 affect Alzheimer’s disease, vascular restructuring, and exacerbation of neuroinflammation, and how their inhibition helps improve cognitive function. In addition, the results of the animal behavior analysis experiments utilizing the Morris water maze were compared through meta-analysis to analyze the effects of ROCK inhibitors and PDE-5 inhibitors on cognitive function. According to the selection criteria, 997 publications on ROCK and 1772 publications on PDE-5 were screened, and conclusions were drawn through meta-analysis. Both inhibitors showed good improvement in cognitive function tests, and what is expected of the synergy effect of the two drugs was confirmed in this review.

Changes in Anxiety Level and Personal Protective Equipment Use Among Healthcare Workers Exposed to COVID-19

BACKGROUND

The relationship between changes in anxiety levels and personal protective equipment (PPE) use is yet to be evaluated. The present study assessed this relationship among healthcare workers (HCWs) involved in the care of patients with coronavirus disease 2019 (COVID-19).

METHODS

An online survey was conducted in a municipal hospital with 195 nationally designated negative pressure isolation units in Korea. Anxiety level was measured using the self-rating anxiety scale (SAS), and changes in anxiety levels were assessed based on the time when COVID-19 vaccine was introduced in March 2021 in Korea. Monthly PPE usage between June 2020 and May 2021 was investigated.

RESULTS

The mean SAS score (33.25 ± 5.97) was within normal range and was lower than those reported in previous studies conducted before COVID-19 vaccination became available. Among the 93 HCWs who participated, 64 (68.8%) answered that their fear of contracting COVID-19 decreased after vaccination. The number of coveralls used per patient decreased from 33.6 to 0. However, a demand for more PPE than necessary was observed in situations where HCWs were exposed to body fluids and secretions (n = 38, 40.9%). Excessive demand for PPE was not related to age, working experience, or SAS score.

CONCLUSION

Anxiety in HCWs exposed to COVID-19 was lower than it was during the early period of the pandemic, and the period before vaccination was introduced. The number of coveralls used per patient also decreased although an excessive demand for PPE was observed.

Effectiveness of Regdanvimab at Preventing the Need for Oxygen Therapy in Patients with Mild-to-Moderate COVID-19: A Retrospective Cohort Study

BACKGROUND

Monoclonal antibodies are a treatment option for patients with mild-to-moderate coronavirus disease (COVID-19). We investigated the effectiveness of regdanvimab, an anti-severe acute respiratory syndrome coronavirus-2 monoclonal antibody approved in Korea, in the treatment of patients with mild-to-moderate COVID-19.

MATERIALS AND METHODS

Medical records of patients who were admitted to a COVID-19 designated hospital during the study period of February 1 to June 31 and met the indications for administration of regdanvimab were reviewed to assess baseline characteristics and clinical outcomes such as supplemental oxygen requirements, mortality, and length of hospitalization. Multivariable logistic regression analysis was conducted to identify factors associated with requiring supplemental oxygen. Subgroup analysis was performed according to the presence of pneumonia confirmed on a chest X-ray.

RESULTS

Three hundred ninety-eight COVID-19 patients were included in the study, and 65 (16.3%) of them were administered regdanvimab. The proportion of patients requiring supplemental oxygen was significantly lower in the regdanvimab group than in the control group (6.2% vs. 20.1%, P = 0.007). There was no significant difference in mortality (0% vs. 1.5%, P >0.999) and the length of hospitalization (median: 10 days vs. 10 days, P = 0.267) between two groups. The multivariable analysis demonstrated that administration of regdanvimab was independently associated with lower oxygen supplement [odds ratio (OR): 0.20, 95% confidence interval (CI): 0.06 - 0.55, P = 0.004] after adjustment of potential risk factors related to supplemental oxygen including age, sex, chest X-ray abnormality, and underlying chronic kidney disease. Among the patients with pneumonia radiologically, administration of regdanvimab was also associated with lower risk of oxygen supplement (OR: 0.13, 95% CI: 0.02 - 0.46, P = 0.007).

CONCLUSION

Regdanvimab use was related to lower need for supplemental oxygen in patients with mild-to-moderate COVID-19 for the indications for administration of regdanvimab.

Inflammation and Rho-Associated Protein Kinase-Induced Brain Changes in Vascular Dementia

Patients with vascular dementia, caused by cerebral ischemia, experience long-term cognitive impairment due to the lack of effective treatment. The mechanisms of and treatments for vascular dementia have been investigated in various animal models; however, the insufficient information on gene expression changes that define pathological conditions hampers progress. To investigate the underlying mechanism of and facilitate treatment development for vascular dementia, we established a mouse model of chronic cerebral hypoperfusion, including bilateral carotid artery stenosis, by using microcoils, and elucidated the molecular pathway underlying vascular dementia development. Rho-associated protein kinase (ROCK) 1/2, which regulates cellular structure, and inflammatory cytokines (IL-1 and IL-6) were upregulated in the vascular dementia model. However, expression of claudin-5, which maintains the blood–brain barrier, and MAP2 as a nerve cell-specific factor, was decreased in the hippocampal region of the vascular dementia model. Thus, we revealed that ROCK pathway activation loosens the tight junction of the blood–brain barrier and increases the influx of inflammatory cytokines into the hippocampal region, leading to neuronal death and causing cognitive and emotional dysfunction. Our vascular dementia model allows effective study of the vascular dementia mechanism. Moreover, the ROCK pathway may be a target for vascular dementia treatment development in the future.

Treatment for Immune Thrombocytopenia in Coronavirus Disease 2019 (COVID-19) Infection after COVID-19 Vaccination: A Case Report

Thrombocytopenia is one of the rare signs of both the coronavirus disease 2019 (COVID-19) and COVID-19 vaccination. An 85-year-old man was diagnosed with immune thrombocytopenia and COVID-19, 7 days after COVID-19 vaccination. The patient was successfully treated with a short course of intravenous immunoglobulin and oral corticosteroids.

Early Oxygen Requirement in Patients with Mild-to-Moderate COVID-19 Who Received Regdanvimab after Delta-Variant Outbreak

Background

Regdanvimab is a monoclonal antibody targeted against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and a treatment option for patients with mild-to moderate coronavirus disease 2019 (COVID-19). However, there has been limited information on the clinical effectiveness of regdanvimab in the Delta variant of SARS-CoV-2. Therefore, we aimed to investigate the effectiveness of regdanvimab after the Delta variant was dominant using chronological analysis of regdanvimab use in a real-world setting.

Materials and Methods

The electrical medical records of patients infected with mild-to-moderate COVID-19 who received regdanvimab within 7 days of symptom onset were reviewed before (February – June 2021) and after (August – November 2021) the Delta variant became predominant in Korea. Clinical outcomes were assessed by the need for oxygen supplementation, time from symptom onset to oxygen requirement, in-hospital mortality, and length of hospitalization. To match the difference between the basic characteristics of the two groups, the clinical outcomes were compared again after 1 : 1 propensity score matching.

Results

Patients treated with regdanvimab in the Delta-predominant group were more likely to require oxygen supplementation (17.5% vs. 6.0%, P = 0.019) and had shorter times from symptom onset to supplemental oxygen use (mean ± standard deviation [SD]: 5.8 ± 2.8 vs. 10.0 ± 3.7, P = 0.007) than those in the control group. After propensity score matching, the percentage of patient requiring oxygen supplementation was higher (15.2% vs. 6.1%, P = 0.156), while the time from symptom onset to oxygen supplementation was significantly shorter in the Delta-predominant group (mean ± SD: 4.9 ± 2.1 vs. 10.0 ± 3.7, P = 0.007) than that in the control group.

Conclusion

Considering that high proportion of vaccinated patients in the Delta-predominant group, this finding suggests the uncertainty whether the effect of regdanvimab is maintained even during the Delta-predominant period. It is hence necessary to continuously monitor the effectiveness of regdanvimab as new SARS-CoV-2 variants emerge.

Prevalence of Multidrug-Resistant Tuberculosis in HIV/Tuberculosis Co-Infected Patients

Tuberculosis (TB) is a common opportunistic infection in human immunodeficiency virus (HIV)-infected patients. Patients with multidrug-resistant (MDR)-TB have poor outcomes. This study aimed to determine the prevalence of MDR-TB in HIV/TB co-infected patients in the Korea. We reviewed the medical records of HIV/TB co-infected patients at two university hospitals between January 1998 and December 2020. During the study period, a total of 87 HIV/TB co-infected patients were identified, and drug susceptibility test results were available for 44 of them. The prevalence of MDR-TB in the study population was 15.9% (7/44, 95% confidence interval, 5.1 - 26.7).

Multi-omics analysis reveals the genetic basis of rice fragrance mediated by betaine aldehyde dehydrogenase 2

INTRODUCTION

Fragrance is an important economic and quality trait in rice. The trait is controlled by the recessive gene betaine aldehyde dehydrogenase 2 (BADH2) via the production of 2-acetyl-1-pyrroline (2AP).

OBJECTIVES

Variation in BADH2 was evaluated at the population, genetic, transcriptional, and metabolic levels to obtain insights into fragrance regulation in rice.

METHODS

Whole-genome resequencing of the Korean World Rice Collection of 475 rice accessions, including 421 breeding lines and 54 wild accessions, was performed. Transcriptome analyses of a subset of 279 accessions, proteome analyses of 64 accessions, and volatile profiling of 421 breeding lines were also performed.

RESULTS

We identified over 3.1 million high-quality single nucleotide polymorphisms (SNPs) in Korean rice collection. Most SNPs were present in intergenic regions (79%), and 190,148 SNPs (6%) were located in the coding sequence, of which 53% were nonsynonymous. In total, 38 haplotypes were identified in the BADH2 coding region, including four novel haplotypes (one in cultivated and three in wild accessions). Tajima's D values suggested that BADH2 was under balancing selection in japonica rice. Furthermore, we identified 316 expression quantitative trait loci (eQTL), including 185 cis-eQTLs and 131 trans-eQTLs, involved in BADH2 regulation. A protein quantitative trait loci (pQTL) analysis revealed the presence of trans-pQTLs; 13 pQTLs were mapped 1 Mbp from the BADH2 region. Based on variable importance in projection (VIP) scores, 15 volatile compounds, including 2AP, discriminated haplotypes and were potential biomarkers for rice fragrance.

CONCLUSION

We generated a catalog of haplotypes based on a resequencing analysis of a large number of rice accessions. eQTLs and pQTLs associated with BADH2 gene expression and protein accumulation are likely involved in the regulation of 2AP variation in fragrant rice. These data improve our understanding of fragrance and provide valuable information for rice breeding.

Correspondence between neuroevolution and gradient descent

We show analytically that training a neural network by conditioned stochastic mutation or neuroevolution of its weights is equivalent, in the limit of small mutations, to gradient descent on the loss function in the presence of Gaussian white noise. Averaged over independent realizations of the learning process, neuroevolution is equivalent to gradient descent on the loss function. We use numerical simulation to show that this correspondence can be observed for finite mutations, for shallow and deep neural networks. Our results provide a connection between two families of neural-network training methods that are usually considered to be fundamentally different.

Gradient-based and non-gradient-based methods for training neural networks are usually considered to be fundamentally different. The authors derive, and illustrate numerically, an analytic equivalence between the dynamics of neural network training under conditioned stochastic mutations, and under gradient descent.

Post-Stroke Depressive Symptoms: Varying Responses to Escitalopram by Individual Symptoms and Lesion Location

OBJECTIVE

The efficacy of antidepressants in post-stroke depressive symptoms (PSD) varies. We aimed to examine whether the effect of escitalopram on PSD differs according to individual depressive symptoms and stroke lesion location.

METHODS

This is a post hoc analysis of EMOTION (ClinicalTrials.gov, NCT01278498), a randomized, placebo-controlled, double-blind trial that examined the efficacy of escitalopram on depression in acute stroke patients (237 with placebo, 241 with escitalopram). Depressive symptoms were evaluated with the 10-item Montgomery-Åsberg Depression Rating Scale (MADRS). Changes in MADRS and individual item scores at 12 weeks were compared between the treatment groups and among the stroke lesion location groups. Stroke lesion locations were grouped according to the anatomical distribution of serotonin fibers that originate from the midbrain/pons and spread to the forebrain via subcortical structures: "Midbrain-Pons," "Frontal-Subcortical," and "Others." Least-squares means were calculated to demonstrate the independent effect of lesion location.

RESULTS

Total MADRS scores decreased more significantly in the escitalopram than in the placebo group, while a significant effect of escitalopram was observed in only 3 items: apparent sadness, reported sadness, pessimistic thoughts. In the lesion location analyses, escitalopram users in the Frontal-Subcortical group showed significant improvement in total MADRS scores (placebo [n = 130] vs. escitalopram [n = 148], least-square mean [95% CI]: -2.3 [-3.5 to -0.2] vs. -4.5 [-5.5 to -3.4], p = .005), while those in the Midbrain-Pons and Others groups did not.

CONCLUSIONS

The effect of escitalopram on PSD may be more prominent in patients with particular depressive symptoms and stroke lesion locations, suggesting the need for tailored treatment strategies.

Predictors of mortality in patients with left-side infective endocarditis, the ESC-EORP EURO-ENDO registry

Background/Introduction

Infective endocarditis (IE) is associated with high in-hospital mortality, ranging from 16% to 25%, despite improvement in diagnostic and therapeutic strategies, mainly due to complications and heterogeneity of the disease. Baseline risk stratification is essential, in order to focus an aggressive management toward high-risk patients.

Purpose

We sought to assess the association between surgery and 30-day mortality rate as related to vegetation size.

Methods

The ESC-EORP EURO-ENDO registry is a prospective multicentre observational study of patients presenting with definite or possible IE in Europe and ESC-affiliated/non-affiliated countries. Patients were included from January 2016 to 31 March 2018 in 156 centers from 40 countries. Clinical data, blood test analysis and multi-modality imaging tests (echocardiography, computed tomography, PET-CT, magnetic resonance) were collected. Primary endpoint was 30-day mortality. Multivariable logistic regression analysis was performed to assess variables associated with 30-day mortality. Besides, univariable analysis was performed to assess best vegetation size cut-off related to 30-day mortality.

Results

Among 2171 patients with left-side IE, 257 patients (11.8%) died during the first 30 days of IE diagnosis. Patient characteristics and univariable analysis are summarized in TABLE 1. Cut-off value for best vegetation size related to 30-day mortality was vegetation length &gt;14mm, with a HR =2.00 (95% CI 1.59–2.51, p&lt;0.0001) and a Harrell's Concordance of 0.58. After multivariable logistic regression analysis, factors associated with 30-day mortality risk were: vegetation size &gt;14mm (OR =2.68, 95% CI [1.96–3.67], p&lt;0.0001), previous stroke or transient ischemic attack (TIA) (OR =1.60, 95% CI [1.07–2.40], p=0.0235), creatinine &gt;2mg/dL (OR =2.45, 95% CI [1.73–3.47], p&lt;0.0001), presence of embolic events (OR =2.64, 95% CI [1.86–3.74], p&lt;0.0001), hemorrhagic stroke (OR=3.71, 95% CI [1.80–7.64], p=0.0004), presence of heart failure or cardiogenic shock (OR =3.50, 95% CI [2.57–4.77], p&lt;0.0001) and no cardiac surgery during the event (OR =4.07, 95% CI [2.93–5.67], p&lt;0.0001). The C-statistic of the logistic model to predict 30-day mortality was 0.795.

Conclusion

Left-side infective endocarditis had a high 30-day mortality rate (11.8%). Presence of a large vegetation size (&gt;14mm), embolic events, hemorrhagic stroke, renal failure, presence of heart failure or cardiogenic shock were associated with an increase in 30-day mortality. Performing cardiac surgery had a protective effect.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): ESC-EORP EURO-ENDO project from the ESC society

Predictors of mortality in patients with right-side and cardiac device-related infective endocarditis, the esc-eorp euro-endo registry

Background/Introduction

Mortality in right-sided infective endocarditis (RSIE) and cardiac device-related IE (CDRIE) rates have increased mainly due derived complications and heterogeneity of the disease. A better understanding of associated risk factors to mortality in these entities are required in order to develop an efficient therapy.

Purpose

The aim of this study was to assess 30-day mortality rate and variables associated in RSIE and CDRIE.

Methods

The ESC-EORP EURO-ENDO registry is a prospective multicenter observational study of patients presenting with definite or possible IE in Europe and ESC-affiliated/non-affiliated countries. Patients were included from January 2016 to 31 March 2018 in 156 centers from 40 countries. Clinical data, blood test analysis and multi-modality imaging tests (echocardiography, computed tomography, PET-CT, magnetic resonance) were collected. Primary endpoint was 30-day mortality. Univariable analysis was performed to assess variables associated with 30-day mortality.

Results

Among 269 patients with RSIE, 24 patients (9.8%) died during the first 30-day of IE diagnosis. Cut-off value for best vegetation size related to 30-day mortality was vegetation length &gt;19mm, with a HR = 2.88 (95% CI 1.26–6.58, p=0.01) and a Harrell's Concordance of 0.632. Factors associated with 30-days mortality by univariable analysis were: vegetation size &gt;19mm (OR = 2.99, 95% CI [1.31–6.84], p=0.009), previous stroke or transient ischemic attack (OR = 5.10, 95% CI [1.19–21.88], p=0.029), HIV infection (OR = 3.52, 95% CI [1.03–12.10], p=0.046), chronic renal failure (OR = 2.66, 95% CI [1.06–6.71], p=0.038), congestive heart failure at admission (OR = 2.34, 95% CI [1.00–5.47], p=0.050) and severe regurgitation (OR = 3.77, 95% CI [1.56–9.09], p=0.003).

On the other side, among the 227 patients with CDRIE, 24 patients (8.8%) died during the first 30-day of IE diagnosis. Factors associated with an increase in 30-day mortality by univariate analysis were: age per 10 years (OR = 1.49, 95% CI [1.02–2.18], p=0.039), heart failure history (OR = 3.88, 95% CI [1.39–10.80], p=0.009), congestive heart failure on admission (OR = 5.80, 95% CI [2.31–14.55], p&lt;0.001) and cardiogenic shock on admission (OR = 13.37, 95% CI [3.75–47.64], p&lt;0.001). An increase in left ventricular ejection fraction (LVEF) per 10% was a protective factor (OR = 0.66, 95% CI [0.49–0.90], p=0.008).

Conclusions

Patients with RSIE and CDRIE had a not negligible 30-day mortality rate (9.8% and 8.8%, respectively). Factors associated with RSIE and CDRIE mortality are different; while in the right side location, the mortality was related with vegetation size and comorbidities, in the case of CDRIE, the mortality was mainly associated to the presence of heart failure.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Euro-Endo registry by European Society of Cardiology

Deciphering the role of a membrane-targeting domain in assisting endosomal and autophagic membrane localization of a RavZ protein catalytic domain

The bacterial effector protein RavZ from a pathogen can impair autophagy in the host by delipidating the mammalian autophagy- related gene 8 (mATG8)-phosphatidylethanolamine (PE) on autophagic membranes. In RavZ, the membrane-targeting (MT) domain is an essential function. However, the molecular mechanism of this domain in regulating the intracellular localization of RavZ in cells is unclear. In this study, we found that the fusion of the green fluorescent protein (GFP) to the MT domain of RavZ (GFP-MT) resulted in localization primarily to the cytosol and nucleus, whereas the GFP-fused duplicated-MT domain (GFP-2xMT) localized to Rab5- or Rab7-positive endosomes. Similarly, GFP fusion to the catalytic domain (CA) of RavZ (GFP-CA) resulted in localization primarily to the cytosol and nucleus, even in autophagy-induced cells. However, by adding the MT domain to GFP-CA (GFP-CA-MT), the cooperation of MT and CA led to localization on the Rab5-positive endosomal membranes in a wortmannin-sensitive manner under nutrient-rich conditions, and to autophagic membranes in autophagy-induced cells. In autophagic membranes, GFP-CA-MT delipidated overexpressed or endogenous mATG8-PE. Furthermore, GFP-CAΔα3-MT, an α3 helix deletion within the CA domain, failed to localize to the endosomal or autophagic membranes and could not delipidate overexpressed mATG8-PE. Thus, the CA or MT domain alone is insufficient for stable membrane localization in cells, but the cooperation of MT and CA leads to localization to the endosomal and autophagic membranes. In autophagic membranes, the CA domain can delipidate mATG8-PE without requiring substrate recognition mediated by LC3-interacting region (LIR) motifs. [BMB Reports 2021; 54(2): 118-123].

Association between pain and gait instability in patients with lumbar disc herniation

Objective

To determine whether pain is associated with gait instability in patients with lumbar disc herniation (LDH).

Methods

This retrospective cross-sectional study used data from electronic medical records. Among patients with lumbar back pain caused by LDH between January 2017 and July 2019, patients that underwent gait analysis were included. LDH was diagnosed using magnetic resonance imaging. An OptoGait photoelectric cell system was used for gait evaluation. Instability was measured using a gait symmetry index. Multivariate linear regression analysis was performed to determine the association between lumbar pain and gait instability.

Results

A total of 29 patients (12 females [41.4%] and 17 males [58.6%]; mean ± SD age, 40.6 ± 12.0 years) with LDH were enrolled in the study. With each 1-point increase in lumbar pain on the numeric rating scale, the symmetry index of the stance phase (0.33; 95% confidence interval [CI] 0.04, 0.62), swing phase (0.78; 95% CI 0.14, 1.43) and single support (0.79; 95% CI 0.15, 1.43) increased.

Conclusions

Gait instability in patients with LDH may occur due to an increase in pain.

Dissociative and Associative Concerted Mechanism for Ammonia Synthesis over Co-Based Catalyst

The current catalytic reaction mechanism for ammonia synthesis relies on either dissociative or associative routes, in which adsorbed N₂ dissociates directly or is hydrogenated step-by-step until it is broken upon the release of NH₃ through associative adsorption. Here, we propose a concerted mechanism of associative and dissociative routes for ammonia synthesis over a cobalt-loaded nitride catalyst. Isotope exchange experiments reveal that the adsorbed N₂ can be activated on both Co metal and the nitride support, which leads to superior low-temperature catalytic performance. The cooperation of the surface low work function (2.6 eV) feature and the formation of surface nitrogen vacancies on the CeN support gives rise to a dual pathway for N₂ activation with much reduced activation energy (45 kJ·mol^-1) over that of Co-based catalysts reported so far, which results in efficient ammonia synthesis under mild conditions.

A View on Formation Gap in Transition Metal Hydrides and Its Collapse

Late transition metals (LTMs) do not form hydrides under conventional experimental conditions except for palladium (Pd). The incorporation of a small amount of metal with low electronegativity converts LTMs into hydrogen (H) storage intermetallics (IMs) such as LaNi₅. We examined the critical property of the H absorbing ability of LTMs and found that the lattice softness of Pd is a unique parameter for H insertion. This idea is applicable to H storage IMs. Indeed, negatively charged LTM ions, such as Ni^δ- in LaNi₅, play a crucial role in hydrogenation. These ions cause lattice softening, which renders H solution possible. As a result, we propose that lattice softness can be an effective criterion for the development of new H storage IMs.

Effect of Zinc Oxide Nanoparticle Addition to Polycaprolactone Periodontal Membranes on Antibacterial Activity and Cell Viability

During the design of membranes for guided tissue regeneration (GTR) to treat periodontal diseases, infection of the exposed membranes and postoperative complications can be prevented by increasing bacterial resistance. This study evaluated the antibacterial activity of PCL/ZnO membranes and their effect on cell viability via addition of antibacterial zinc oxide (ZnO) nanoparticles to a biocompatible and biodegradable material such as polycaprolactone (PCL). Neat PCL membranes and PCL/ZnO membranes containing 0.5 wt.% and 5 wt.% ZnO were produced, and divided into PCL (0% ZnO), LZ (0.5 wt.% ZnO), and HZ (5 wt.% ZnO) groups, respectively. The surface characteristics of the membranes including morphological features and changes in composition were analyzed. Adhesion of bacteria, including Streptococcus mutans and Porphyromonas gingi-valis, was analyzed using a crystal violet assay. The proliferation of MC3T3-E1 osteoblasts was evaluated using a WST-8 assay. Significant differences were analyzed using the Kruskal-Wallis test (P < 0.05). The results of groups were compared using the Mann-Whitney test (P < 0.017). ZnO nanoparticles were dispersed in the PCL matrix of PCL/ZnO membranes. Compared with neat PCL membranes, their ability to form crystals decreased and their amorphous structure increased. The adhesion of S. mutans and P. gingivalis in the LZ and HZ groups containing ZnO was significantly decreased compared with that of the neat PCL membranes (P < 0.05). No significant differences were observed in the proliferation of MC3T3-E1 cells between the PCL/ZnO membranes and the neat PCL membranes both on days 2 and 5 of culture (P > 0.05). This study has demonstrated that the PCL membranes carrying the ZnO nanoparticles inhibited bacterial adhesion without affecting the viability of osteoblasts, suggesting the potential application of ZnO in GTR to increase antibacterial activity of membranes.