Highly Resilient Noncovalently Associated Hydrogel Adhesives for Wound Sealing Patch

The development of hydrogel adhesives with high mechanical resilience and toughness remains a challenging task. Hydrogels must exhibit high mechanical resilience to withstand the inevitable movement of the human body while simultaneously demonstrating strong wet tissue adhesion and appropriate toughness to hold and seal damaged tissues; However, tissue adhesion, toughness, and mechanical resilience are typically negatively correlated. Therefore, this paper proposes a highly resilient double-network (DN) hydrogel wound-sealing patch that exhibits a well-balanced combination of tissue adhesion, toughness, and mechanical resilience. The DN structure is formed by introducing covalently and non-covalently crosslinkable dopamine-modified crosslinkers and physically interactable linear poly(vinyl imidazole) (PVI). The resulting hydrogel adhesive exhibits high toughness and mechanical resilience due to the presence of a DN involving reversible physical intermolecular interactions such as hydrogen bonds, hydrophobic associations, cation-π interactions, π-π interactions, and chain entanglements. Moreover, the hydrogel adhesive achieves strong wet tissue adhesion through the polar hydroxyl groups of dopamine and the amine group of PVI. These mechanical attributes allow the proposed adhesive to effectively seal damaged tissues and promote wound healing by maintaining a moist environment.

Effects of Growth Hormone-Releasing Hormone (GHRH) Plasmid Treatment on the Reproductive Productivity of Sows in Primiparous and Multiparous Sow Breeds

The effect of growth hormone-releasing hormone (GHRH) plasmid treatment on sow reproductive performance was examined. Forty pregnant sows (three-way crossbreed: Landrace × Yorkshire × Duroc) at 85 days of gestation were included in the study and consisted of twenty primiparous and twenty multiparous sows (third parity). Sows were randomly assigned to the control and treatment groups. The treatment group received 5 mg dose of GHRH plasmid injection via electroporation, whereas the control group received a phosphate buffer solution. Reproductive indicators, including serum insulin-like growth factor-1 (IGF-1) concentration and weaned piglet data, were assessed. In the GHRH plasmid-treated group, serum IGF-1 concentration significantly increased compared with that in the control group, a trend observed in primiparous and multiparous sows. The key indicator of reproductive performance, litter size, showed that for control primiparous sows (C-PS), it was 10.90 ± 0.99 kg, while for control multiparous sows (C-MS), it was 14.00 ± 0.67 kg. Furthermore, for primiparous sows treated with GHRH plasmid (G-PS), the litter size was 11.60 ± 0.97 kg, and for multiparous sows treated with GHRH plasmid (G-MS), it was 14.00 ± 0.82 kg. The GHRH plasmid-treated group also exhibited a higher number of total births and surviving piglet numbers, along with a decrease in stillborn piglets; however, there was no significant difference in birth weight. The results suggest that GHRH plasmid treatment can enhance the reproductive performance of sows.

Low Tesla MR Imaging for Spine with Hardware

PURPOSE/OBJECTIVE(S)

Acquiring MR images with minimized susceptibility artifacts is essential for spines with medical hardware to delineate clinical target volumes (CTVs) in radiation therapy for chordomas, chondrosarcomas, and other sarcomas. Since it can be more challenging to visualize the primary structures in high-tesla MR images due to metal-induced artifacts, we optimized imaging parameters to acquire high-quality, low-tesla MR images for clinical use.

MATERIALS/METHODS

OptimalMR imaging parameters were investigated under general guidelines for artifact reduction techniques by testing several 3D spin echo and gradient echo sequences in a 0.23-T MR scanner. A customized spine phantom was developed to acquire MR images for bony materials which included, 4-6 industrial titanium screws, an aluminum plate, and a superflab bolus. While the 3D b-FFE sequence was used to acquire MR images with a high signal-to-noise ratio, the other 3D T1-FFE, THRIVE, and DTSE sequences were applied to reduce susceptible artifacts to the medical hardware. The optimized parameters determined in the phantom test were applied to the 15 clinical cases, including patients with residual spinal tumors and fusion hardware. The low-tesla MR imaging technique was also used to scan sarcomas of the extremities and re-irradiation cases of spinal metastases.

RESULTS

The optimized low-tesla MR images in the spine were noticeably useful to guide CTV delineations for patients with medical hardware, especially for residual or recurrent tumors. The imaging technique to minimize susceptibility artifacts enabled a more defined separation of each hardware component from the spinal cord and CTVs. In spine metastasis cases, pre-irradiated target volumes were determined, reflecting property changes in the bone marrow.

CONCLUSION

The MR images acquired using the optimized parameters showed minimal artifacts to scan spine patients with hardware. By using the low-tesla MR images, spinal chordoma and chondrosarcoma patients could be treated to improve tumor control probabilities with minimized complications.

Development of a Filtimator for Pediatric Image-Guided Radiation Therapy with Low Imaging Dose

PURPOSE/OBJECTIVE(S)

We propose to use the filtimator (a filter and a collimator) for CBCT-based image-guided radiation therapy (IGRT) optimized for pediatric patients to minimize the imaging dose but not to sacrifice the imaging quality required for bony-based image fusion.

MATERIALS/METHODS

The filtimator was made of Tin (0.6 - 1 mm) and Cu sheets (0.6 to 1.2mm) for filter and collimation with adjustable collimation with 4 to 6 cm fields at the isocenter. The thickness of the filter in the central and the peripheral regions were determined using vendor-provided image registration software and to ensure that the rigid image registration results from the CBCT were with and without the filtimator. The image quality of the filtered CBCT was compared with the regular CBCTs. Image registration accuracy was investigated by creating a < 2° shift in pitch, roll, and rotation and < 3 cm shifts in the lateral, vertical, and longitudinal directions, using commercial head and house-made phantoms. The imaging dose reduction factor of the filtimator was measured using a CT dose index phantom.

RESULTS

The contrast-to-noise ratio substantially improved in the opening region of the filter, which provided better visualization of normal anatomy and target volumes. The slim filter reduced the imaging dose by > 98% in the filtered region, and the visualization of bony structures was well preserved, allowing for accurate rigid image registration with the filter. The imaging registration difference was < 0.2° shift in pitch, roll, and rotation and < 0.5 mm shift in the lateral, vertical, and longitudinal directions compared to the regular CBCT.

CONCLUSION

The proposed dose reduction with the filtimator was demonstrated to be efficient and effective in considerably reducing the patient imaging dose while yielding accurate registration results. This novel technique can become a valuable tool for generating 3- and 4-dimensional images with a much-reduced dose to improve the precision of target localization in radiation therapy.

Appropriateness of antibiotic use for patients with asymptomatic bacteriuria or urinary tract infection with positive urine culture: a retrospective observational multi-centre study in Korea

BACKGROUND

Antibiotic resistance threatens public health worldwide, and inappropriate use of antibiotics is one of the main causes.

AIM

To evaluate qualitative use of antibiotics in asymptomatic bacteriuria (ABU) and urinary tract infection (UTI).

METHODS

Cases of positive urine culture (≥105 colony-forning units/mL) performed in inpatient, outpatient and emergency departments in April 2021 were screened in 26 hospitals in the Republic of Korea. The cases were classified as ABU, lower UTI and upper UTI. The appropriateness of antibiotic use was evaluated retrospectively by infectious disease specialists using quality indicators based on clinical guidelines for ABU and UTI.

RESULTS

This study included a total of 2697 patients with ABU or UTI. The appropriateness of antibiotic use was assessed in 1157 patients with ABU, and in 677 and 863 patients with lower and upper UTI, respectively. Among the 1157 patients with ABU, 251 (22%) were prescribed antibiotics without appropriate indications. In 66 patients with ABU in which antibiotics were prescribed with appropriate indications, the duration was adequate in only 23 (34.8%) patients. The appropriateness of empirical and definite antibiotics was noted in 527 (77.8%) and 353 (68.0%) patients with lower UTI, and 745 (86.3%) and 583 (78.2%) patients with upper UTI, respectively. The duration of antibiotics was adequate in 321 (61.8%) patients with lower UTI and 576 (78.7%) patients with upper UTI.

CONCLUSIONS

This nationwide qualitative assessment of antibiotic use in ABU and UTI revealed that antibiotics were often prescribed inappropriately, and the duration of antibiotics was unnecessarily prolonged.

Hormonal stimulation reduces numbers and impairs function of human uterine natural killer cells during implantation

STUDY QUESTION

How does an altered maternal hormonal environment, such as that seen during superovulation with gonadotropins in ART, impact human uterine immune cell distribution and function during the window of implantation?

SUMMARY ANSWER

Hormonal stimulation with gonadotropins alters abundance of maternal immune cells including uterine natural killer (uNK) cells and reduces uNK cell ability to promote extravillous trophoblast (EVT) invasion.

WHAT IS KNOWN ALREADY

An altered maternal hormonal environment, seen following ART, can lead to increased risk for adverse perinatal outcomes associated with disordered placentation. Maternal immune cells play an essential role in invasion of EVTs, a process required for proper establishment of the placenta, and adverse perinatal outcomes have been associated with altered immune cell populations. How ART impacts maternal immune cells and whether this can in turn affect implantation and placentation in humans remain unknown.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was carried out between 2018 and 2021 on 51 subjects: 20 from natural cycles 8 days after LH surge; and 31 from stimulated IVF cycles 7 days after egg retrieval.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometrial biopsies and peripheral blood samples were collected during the window of implantation in subjects with regular menstrual cycles or undergoing superovulation. Serum estradiol and progesterone levels were measured by chemiluminescent competitive immunoassay. Immune cell populations in blood and endometrium were analyzed using flow cytometry. uNK cells were purified using fluorescence-activated cell sorting and were subjected to RNA sequencing (RNA-seq). Functional changes in uNK cells due to hormonal stimulation were evaluated using the implantation-on-a-chip (IOC) device, a novel bioengineered platform using human primary cells that mimics early processes that occur during pregnancy in a physiologically relevant manner. Unpaired t-tests, one-way ANOVA, and pairwise multiple comparison tests were used to statistically evaluate differences.

MAIN RESULTS AND THE ROLE OF CHANCE

Baseline characteristics were comparable for both groups. As expected, serum estradiol levels on the day of biopsy were significantly higher in stimulated (superovulated) patients (P = 0.0005). In the setting of superovulation, we found an endometrium-specific reduction in the density of bulk CD56+ uNK cells (P < 0.05), as well as in the uNK3 subpopulation (P = 0.025) specifically (CD103+ NK cells). In stimulated samples, we also found that the proportion of endometrial B cells was increased (P < 0.0001). Our findings were specific to the endometrium and not seen in peripheral blood. On the IOC device, uNK cells from naturally cycling secretory endometrium promote EVT invasion (P = 0.03). However, uNK cells from hormonally stimulated endometrium were unable to significantly promote EVT invasion, as measured by area of invasion, depth of invasion, and number of invaded EVTs by area. Bulk RNA-seq of sorted uNK cells from stimulated and unstimulated endometrium revealed changes in signaling pathways associated with immune cell trafficking/movement and inflammation.

LIMITATIONS, REASONS FOR CAUTION

Patient numbers utilized for the study were low but were enough to identify significant overall population differences in select immune cell types. With additional power and deeper immune phenotyping, we may detect additional differences in immune cell composition of blood and endometrium in the setting of hormonal stimulation. Flow cytometry was performed on targeted immune cell populations that have shown involvement in early pregnancy. A more unbiased approach might identify changes in novel maternal immune cells not investigated in this study. We performed RNA-seq only on uNK cells, which demonstrated differences in gene expression. Ovarian stimulation may also impact gene expression and function of other subsets of immune cells, as well as other cell types within the endometrium. Finally, the IOC device, while a major improvement over existing in vitro methods to study early pregnancy, does not include all possible maternal cells present during early pregnancy, which could impact functional effects seen. Immune cells other than uNK cells may impact invasion of EVTs in vitro and in vivo, though these remain to be tested.

WIDER IMPLICATIONS OF THE FINDINGS

These findings demonstrate that hormonal stimulation affects the distribution of uNK cells during the implantation window and reduces the proinvasive effects of uNK cells during early pregnancy. Our results provide a potential mechanism by which fresh IVF cycles may increase risk of disorders of placentation, previously linked to adverse perinatal outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported by the University of Pennsylvania University Research Funding (to M.M.), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (P50HD068157 to M.M., S.S., and S.M.), National Center for Advancing Translational Sciences of the National Institutes of Health (TL1TR001880 to J.K.), the Institute for Translational Medicine and Therapeutics of the Perelman School of Medicine at the University of Pennsylvania, the Children's Hospital of Philadelphia Research Institute (to S.M.G.), and the National Institute of Allergy and Infectious Diseases (K08AI151265 to S.M.G.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Engineering Silk Protein to Modulate Polymorphic Transitions for Green Lithography Resists

Silk protein is being increasingly introduced as a prospective material for biomedical devices. However, a limited locus to intervene in nature-oriented silk protein makes it challenging to implement on-demand functions to silk. Here, we report how polymorphic transitions are related with molecular structures of artificially synthesized silk protein and design principles to construct a green-lithographic and high-performative protein resist. The repetition number and ratio of two major building blocks in synthesized silk protein are essential to determine the size and content of β-sheet crystallites, and radicals resulting from tyrosine cleavages by the 193 nm laser irradiation induce the β-sheet to α-helix transition. Synthesized silk is designed to exclusively comprise homogeneous building blocks and exhibit high crystallization and tyrosine-richness, thus constituting an excellent basis for developing a high-performance deep-UV photoresist. Additionally, our findings can be conjugated to design an electron-beam resist governed by the different irradiation-protein interaction mechanisms. All synthesis and lithography processes are fully water-based, promising green lithography. Using the engineered silk, a nanopatterned planar color filter showing the reduced angle dependence can be obtained. Our study provides insights into the industrial scale production of silk protein with on-demand functions.

What does family involvement in care provision look like across hospital settings in Bangladesh, Indonesia, and South Korea?

BACKGROUND

Family members provide care whilst staying in the patient's room across a range of cultural settings, irrespective of resource availability in many Asian countries. This has been reported as a contributing factor to the spread of several outbreaks, including COVID-19. Despite these reports, very little is known about the risk of healthcare-associated infection (HAI) transmission related to the involvement of family and private carers in the clinical setting. As a starting point to understanding this issue, this study aimed to provide insights regarding the patient care activities undertaken by family and private carers and the guidance provided to these carers around infection control measures in hospitals located in Bangladesh, Indonesia, and South Korea.

METHOD

A qualitative study involving 57 semi-structured interviews was undertaken in five tertiary level hospitals across the selected countries. Two groups of individuals were interviewed: (1) patients and their family carers and private carers; and (2) healthcare workers, including doctors, nurses, hospital managers and staff members. Drawing upon the principles of grounded theory, an inductive approach to data analysis using thematic analysis was adopted.

RESULTS

Five main themes were generated from the analysis of the data: (1) expectation of family carers staying with a patient; (2) residing in the patient's environment: (3) caring activities undertaken by family carers; (4) supporting and educating family carers and (5) communication around healthcare-associated infection and infection prevention and control.

CONCLUSION

Based on the types of activities being undertaken, coupled with the length of time family and private carers are residing within the clinical setting, coupled with an apparent lack of guidance being given around IPC, more needs to be done to ensure that these carers are not being inadvertently exposed to HAI's or other occupational risks.

Imaging Spatial Distribution of Photogenerated Carriers in Monolayer MoS2 with Kelvin Probe Force Microscopy

The spatial distribution of photogenerated carriers in atomically thin MoS₂ flakes is investigated by measuring surface potential changes under light illumination using Kelvin probe force microscopy (KPFM). It is demonstrated that the vertical redistribution of photogenerated carriers, which is responsible for photocurrent generation in MoS₂ photodetectors, can be imaged as surface potential changes with KPFM. The polarity of surface potential changes points to the trapping of photogenerated holes at the interface between MoS₂ and the substrate as a major mechanism for the photoresponse in monolayer MoS₂. The temporal response of the surface potential changes is compatible with the time constant of MoS₂ photodetectors. The spatial inhomogeneity in the surface potential changes at the low light intensity that is related to the defect distribution in MoS₂ is also investigated.

Variance-aware weight quantization of multi-level resistive switching devices based on Pt/LaAlO3/SrTiO3 heterostructures

Resistive switching devices have been regarded as a promising candidate of multi-bit memristors for synaptic applications. The key functionality of the memristors is to realize multiple non-volatile conductance states with high precision. However, the variation of device conductance inevitably causes the state-overlap issue, limiting the number of available states. The insufficient number of states and the resultant inaccurate weight quantization are bottlenecks in developing practical memristors. Herein, we demonstrate a resistive switching device based on Pt/LaAlO₃/SrTiO₃ (Pt/LAO/STO) heterostructures, which is suitable for multi-level memristive applications. By redistributing the surface oxygen vacancies, we precisely control the tunneling of two-dimensional electron gas (2DEG) through the ultrathin LAO barrier, achieving multiple and tunable conductance states (over 27) in a non-volatile way. To further improve the multi-level switching performance, we propose a variance-aware weight quantization (VAQ) method. Our simulation studies verify that the VAQ effectively reduces the state-overlap issue of the resistive switching device. We also find that the VAQ states can better represent the normal-like data distribution and, thus, significantly improve the computing accuracy of the device. Our results provide valuable insight into developing high-precision multi-bit memristors based on complex oxide heterostructures for neuromorphic applications.

NIR fluorochrome labeled anti-carcinoembryonic antigen monoclonal antibody for gastric cancer-specific image guided surgery

340

Background: Carcinoembryonic antigen (CEA) is a widely known tumor marker that is clearly expressed in gastrointestinal tract cancer. We utilized a CEA-specific chimeric antibody conjugated to a near infrared (NIR) fluorophore to facilitate CEA-targeted fluorescence image–guided surgery (FGS) of gastric cancer. The anti-CEA antibody, SGM-101 is conjugated with NIR dye BM-105, which has an absorbance band centered at 705 nm. Methods: RNA sequencing data of 34 gastric cancer cell lines from Cancer Cell Line Encyclopedia were screened and validated by qPCR and western blotting. Flow cytometry and confocal microscopy were performed by SGM-101, Alexa Fluor-680, Isotype-101 and Isotype-680 to quantify fluorescence intensity. SGM-101(n = 5) or Isotype-101(n = 2) was injected to mouse xenografts through a tail vein which had been subcutaneously implanted with MKN-45, SNU-16, and SNU-668. IVIS Spectrum quantified radiant efficiency of fluorescence in the region of interest at serial time points. The extracted tumor in peak time was analyzed by confocal imaging for microdistribution. In addition, 85As2mLuc were injected intraperitoneally in 6-week-old female BALB/c-nu mice for peritoneal carcinomatosis. Bioluminescence/fluorescence imaging was performed with IVIS Spectrum at peak time and analyzed via Living Image. Histologic evaluations were processed with H&E and Immunohistochemistry (IHC) data by a pathologist. Results: RNA expression of ceacam5 and protein expression of CEA in gastric cell lines was measured by RNA sequencing, qPCR, and western blotting. CEA expression patterns displays similar with fluorescence intensity patterns which were quantified through flow cytometry and immunocytochemistry show that CEA localized in membranes. In subcutaneously implanted model, the radiant efficiency of each group shows that the accumulation of SGM-101 has significantly higher fluorescence signal in the high CEA expressing group (MKN-45) and medium expressing group (SNU-16) while no fluorescence signal was observed in the CEA negative group (SNU-668) via IVIS Spectrum. Biodistribution of SGM-101 indicates that the maximum peak accumulation point was 48 hours after tail vein injection. Frozen tissue which was extracted at peak detection time shows micro-distribution of SGM-101 and expression of extracted tissue CEA expression was validated with IHC by pathological analysis. In the peritoneal carcinomatosis model, the imaging of fluorescence detection patterns corresponds with bioluminescence imaging and histological evaluation. Conclusions: CEA expression corresponded with intensity of in vitro fluorescence immunodetection and a tumor area accumulation in gastric cancer xenografts by SGM-101. This study indicates that NIR tumor specific imaging can be a feasible tool for image-guided surgery.

The potential cytotoxic effects of urban particle matter on olfaction

BACKGROUND

Urban particulate matter (UPM) in ambient air is implicated in a variety of human health issues worldwide, however, few studies exist on the effect of UPM on the olfactory system. This study aimed to identify the factors affecting the destruction of the olfactory system in a mouse model following UPM exposure.

METHODS

Mice were divided into: control and four UPM-exposed groups (200 µg UPM at 1 and 2 weeks, and 400 µg UPM at 1 and 2 weeks [standard reference material 1649b; average particle diameter 10.5 μm]). The olfactory neuroepithelium was harvested for histologic examination, gene ontology, quantitative real-time polymerase chain reaction, and western blotting.

RESULTS

Compared to the control group, olfactory marker protein, Olfr1507, ADCY3, and GNAL mRNA levels were lower, and S-100, CNPase, NGFRAP1, BDNF, and TACR3 mRNA levels were higher in the olfactory neuroepithelium of the UPM groups. Moderately positive correlation was present between the 1- and 2-week groups. After analyzing the 200 and 400 UPM groups separately, the strength of the association between the 200 UPM 1- and 2-week groups was moderately positive. No differences was present in the neuroepithelial inflammatory marker levels between the UPM and control groups.

CONCLUSIONS

UPM could have cytotoxic effects on the olfactory epithelium. The exposure time and particular concentration of UPM exposure could affect the degree of destruction of the olfactory neuroepithelium. The olfactory regeneration mechanism could be related to the neurotrophic factors, olfactory ensheathing cell stimulation, and trigeminal nerve support.

An Artificial Mechano-Nociceptor with Mott Transition

Intelligent touch sensing is now becoming an essential part of various human-machine interactions and communication, including in touchpads, autonomous vehicles, and smart robotics. Usually, sensing of physical objects is enabled by applied force/pressure sensors; however, reported conventional tactile devices are not able to differentiate sharp and blunt objects, although sharp objects can cause unavoidable damage. Therefore, it is central issue to implement electronic devices that can classify sense of touch and simultaneously generate pain signals to avoid further potential damage from sharp objects. Here, concept of force-enabled nociceptive behavior is proposed and demonstrated using vanadium oxide-based artificial receptors. Specifically, versatile criteria of bio-nociceptor like threshold, relaxation, no adaptation, allodynia, and hyperalgesia behaviors are triggered by pointed force, but the device does not mimic any of these by the force applied by blunt objects; thus, the proposed device classifies the intent of touch. Further, supported by finite element simulation, the nanoscale dynamic is unambiguously revealed by conductive atomic force microscopy and results are attributed to the point force-triggered Mott transition, as also confirmed by temperature-dependent measurements. The reported features open a new avenue for developing mechano-nociceptors, which enable a high-level of artificial intelligence within the device to classify physical touch.

Impact of COVID-19 on TB epidemiology in South Korea

SETTING: Five referral hospitals, South Korea.OBJECTIVE: To assess epidemiological changes in TB before and during the COVID-19 pandemic.DESIGN: This was a multicentre cohort study of 3,969 patients diagnosed with TB.RESULTS: We analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years, P < 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019; P = 0.005).CONCLUSIONS: The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.

Light intensity dependence of organic solar cell operation and dominance switching between Shockley-Read-Hall and bimolecular recombination losses

We investigated the variation of current density-voltage (J-V) characteristics of an organic solar cell (OSC) in the dark and at 9 different light intensities ranging from 0.01 to 1 sun of the AM1.5G spectrum. All three conventional parameters, short-circuit currents (Jsc), open-circuit voltage (Voc), and Fill factor (FF), representing OSC performance evolved systematically in response to light intensity increase. Unlike Jsc that showed quasi-linear monotonic increase, Voc and FF showed distinctive non-monotonic variations. To elucidate the origin of such variations, we performed extensive simulation studies including Shockley-Read-Hall (SRH) recombination losses. Simulation results were sensitive to defect densities, and simultaneous agreement to 10 measured J-V curves was possible only with the defect density of [Formula: see text]. Based on analyses of simulation results, we were able to separate current losses into SRH- and bimolecular-recombination components and, moreover, identify that the competition between SRH- and bimolecular-loss currents were responsible for the aforementioned variations in Jsc, Voc, and FF. In particular, we verified that apparent demarcation in Voc, and FF variations, which seemed to appear at different light intensities, originated from the same mechanism of dominance switching between recombination losses.

A therapeutic intervention for Alzheimer's disease using ginsenoside Rg3: its role in M2 microglial activation and non-amyloidogenesis

Previously, we have reported that ginsenoside Rg3 has typical activities for neuroprotection and Aβ42 clearance by modulating microglia. In this study, we determined the pivotal role of ginsenoside Rg3 in microglia and neuronal cells. In human microglia, Rg3 and its stereoisomers significantly restored inflammatory M1 to normal M0 state and promoted M2 activation by up-regulating acute cytokines such as interleukin-10 and Arginase 1. Moreover, scavenger receptor type A (SRA) was significantly elevated in the presence of ginsenoside Rg3 and 20(S)-Rg3. This indicated that ginsenoside Rg3 could play a crucial role in Aβ uptake and clearance under activated M2 state. We also observed that soluble amyloid precursor protein-alpha (sAPPα) and ADAM10 levels were increased in APP swe-transfected Nuro-2a neuronal cells, whereas sAPPβ was not processed, suggesting that ginsenoside Rg3 was involved in non-amyloidogenic processing. In immunocytochemistry, SRA and a disintegrin and metalloproteinase 10 (desintegrin and metalloproteinase-containing protein 10, ADAM10) were coincidently upregulated in the presence of ginsenoside Rg3 and its stereoisomers compared to those in normal control. Taken together, these results suggested that ginsenoside Rg3 could boost acute activation of microglia, promote Aβ uptake, and elevate the sAPPα processing under activated M2 state. Although in vivo studies need to be performed, it is certain that ginsenoside Rg3 is highly involved in ameliorating the pathogenesis of neurodegeneration and can be a promising candidate for treating Alzheimer's disease as a new therapeutic intervention.

High-Speed Imaging of Second-Harmonic Generation in MoS2 Bilayer under Femtosecond Laser Ablation

We report an in situ characterization of transition-metal dichalcogenide (TMD) monolayers and twisted bilayers using a high-speed second-harmonic generation (SHG) imaging technique. High-frequency laser modulation and galvano scanning in the SHG imaging enabled a rapid identification of the crystallinity in the TMD, including the orientation and homogeneity with a speed of 1 frame/s. For a twisted bilayer MoS2, we studied the SHG peak intensity and angles as a function of the twist angle under a strong interlayer coupling. In addition, rapid SHG imaging can be used to visualize laser-induced ablation of monolayer and bilayer MoS2 in situ under illumination by a strong femtosecond laser. Importantly, we observed a characteristic threshold behavior; the ablation process occurred for a very short time duration once the preheating condition was reached. We investigated the laser thinning of the bilayer MoS2 with different twist angles. When the twist angle was 0°, the SHG decreased by approximately one-fourth of the initial intensity when one layer was removed. Conversely, when the twist angle was approximately 60° (the SHG intensity was suppressed), the SHG increased abruptly close to that of the nearby monolayer when one layer was removed. Precise layer-by-layer control was possible because of the unique threshold behavior of the laser-induced ablation.

Controllable, Self-Powered, and High-Performance Short-Wavelength Infrared Photodetector Driven by Coupled Flexoelectricity and Strain Effect

Mechanical deformation-induced strain gradients and coupled spontaneous electric polarization field in centrosymmetric materials, known as the flexoelectric effect, can generate ubiquitous mechanoelectrical functionalities, like the flexo-photovoltaic effect. Concurrently, nano/micrometer-scale inhomogeneous strain reengineers the electronic arrangements and in turn, could alter the fundamental limits of optoelectronic performance. Here, the flexoelectric effect-driven self-powered giant short-wavelength infrared (λ ≤ 1800 nm) photoresponse from centrosymmetric bulk silicon, indeed far beyond the fundamental bandgap (λ = 1100 nm) is demonstrated. Particularly, large on/off ratio (≈10⁵ ), extremely high sensitivity (2.5 × 10⁸ %), good responsivity of 96 mA W^-1 , decent specific detectivity of ≈1.54 × 10¹⁴ Jones, and a rapid response speed of ≈100 µs, even at nanoscale (<30 nm), are measured at λ = 1620 nm. The infrared response sensitivity is tuned in a wide range (up to 1.4 × 10⁸ %) by controlling the applied pointed force from 1 to 10 µN. These results confirm that emerging mechanoelectrical coupling not only sheds to achieve tunable optoelectronic performance beyond the fundamental limit, but also offers innovative numerous applications like mechanoptical switch, photovoltaic, sensors, and self-driving vehicles.

High-Performance and Self-Powered Alternating Current Ultraviolet Photodetector for Digital Communication

Self-powered ultraviolet photodetectors offer great potential in the field of optical communication, smart security, space exploration, and others; however, achieving high sensitivity with maintaining fast response speed has remained a daunting challenge. Here, we develop a titanium dioxide-based self-powered ultraviolet photodetector with high detectivity (≈1.8 × 10¹⁰ jones) and a good photoresponsivity of 0.32 mA W^-1 under pulsed illumination (λ = 365 nm, 4 mW cm^-2), which demonstrate an enhancement of 114 and 2017%, respectively, due to the alternating current photovoltaic effect compared to the conventional direct current photovoltaic effect. Further, the photodetector demonstrated a high on/off ratio (≈10³), an ultrafast rise/decay time of 112/63 μs, and a noise equivalent power of 5.01 × 10^-11 W/Hz^1/2 under self-biased conditions. Photoconductive atomic force microscopy revealed the nanoscale charge transport and offered the possibility to scale down the device size to a sub-10-nanometer (∼35 nm). Moreover, as one of the practical applications, the device was successfully utilized to interpret the digital codes. The presented results enlighten a new path to design energy-efficient ultrafast photodetectors not only for the application of optical communication but also for other advanced optoelectronic applications such as digital display, sensing, and others.

Microsphere-coupled light emission control of van der Waals heterostructures

Two-dimensional transition metal dichalcogenides (TMDCs) integrated into photonic structures provide an intriguing playground for the development of novel optoelectronic devices with improved performance. Here, we show the enhanced light emission from TMDC based van der Waals heterostructures through coupling with microsphere cavities. We observe cavity-induced emission enhancement of TMDC materials which varies by an order of magnitude, depending on the size of the microsphere and thickness of the supporting oxide substrate. Furthermore, we demonstrate microsphere cavity-enhanced electroluminescence of a van der Waals light emitting transistor, showing the potential of 2D material based hybrid optoelectronic structures.

Suppressed Degradation and Enhanced Performance of CsPbI3 Perovskite Quantum Dot Solar Cells via Engineering of Electron Transport Layers

CsPbI₃ perovskite quantum dots (CsPbI₃-PQDs) have recently come into focus as a light-harvesting material that can act as a platform through which to combine the material advantages of both perovskites and QDs. However, the low cubic-phase stability of CsPbI₃-PQDs in ambient conditions has been recognized as a factor that inhibits device stability. TiO₂ nanoparticles are the most regularly used materials as an electron transport layer (ETL) in CsPbI₃-PQD photovoltaics; however, we found that TiO₂ can facilitate the cubic-phase degradation of CsPbI₃-PQDs due to its vigorous photocatalytic activity. To address these issues, we have developed chloride-passivated SnO₂ QDs (Cl@SnO₂ QDs), which have low photocatalytic activity and few surface traps, to suppress the cubic-phase degradation of CsPbI₃-PQDs. Given these advantages, the CsPbI₃-PQD solar cells based on Cl@SnO₂ ETLs show significantly improved device operational stability (under conditions of 50% relative humidity and 1-sun illumination), compared to those based on TiO₂ ETLs. In addition, the Cl@SnO₂-based devices showed improved open circuit voltage and photocurrent density, resulting in enhanced power conversion efficiency (PCE) up to 14.5% compared to that of TiO₂-based control devices (PCE of 13.8%).

Enhanced third-harmonic generation by manipulating the twist angle of bilayer graphene

Twisted bilayer graphene (tBLG) has received substantial attention in various research fields due to its unconventional physical properties originating from Moiré superlattices. The electronic band structure in tBLG modified by interlayer interactions enables the emergence of low-energy van Hove singularities in the density of states, allowing the observation of intriguing features such as increased optical conductivity and photocurrent at visible or near-infrared wavelengths. Here, we show that the third-order optical nonlinearity can be considerably modified depending on the stacking angle in tBLG. The third-harmonic generation (THG) efficiency is found to significantly increase when the energy gap at the van Hove singularity matches the three-photon resonance of incident light. Further study on electrically tuneable optical nonlinearity reveals that the gate-controlled THG enhancement varies with the twist angle in tBLG, resulting in a THG enhanced up to 60 times compared to neutral monolayer graphene. Our results prove that the twist angle opens up a new way to control and increase the optical nonlinearity of tBLG, suggesting rotation-induced tuneable nonlinear optics in stacked two-dimensional material systems.

Imaging Hydrogen Sulfide in Hypoxic Tissue with [99mTc]Tc-Gluconate

Hydrogen sulfide (H₂S) is the third gasotransmitter and is generated endogenously in hypoxic or inflammatory tissues and various cancers. We have recently demonstrated that endogenous H₂S can be imaged with [^99mTc]Tc-gluconate. In the present study, we detected H₂S generated in hypoxic tissue, both in vitro and in vivo, using [^99mTc]Tc-gluconate. In vitro uptake of [^99mTc]Tc-gluconate was measured under hypoxic and normoxic conditions, using the colon carcinoma cell line CT26, and was higher in hypoxic cells than that in normoxic cells. An acute hindlimb ischemia-reperfusion model was established in BALB/c mice by exposing the animals to 3 h of ischemia and 3 h of reperfusion prior to in vivo imaging. [^99mTc]Tc-gluconate (12.5 MBq) was intravenously injected through the tail vein, and uptake in the lower limb was analyzed by single-photon emission computed tomography/computed tomography (SPECT/CT). SPECT/CT images showed five times higher uptake in the ischemic limb than that in the normal limb. The standard uptake value (SUVmean) of the ischemic limb was 0.39 ± 0.03, while that of the normal limb was 0.07 ± 0.01. [^99mTc]Tc-gluconate is a novel imaging agent that can be used both in vitro and in vivo for the detection of endogenous H₂S generated in hypoxic tissue.

Phonon-Polaritons in Lead Halide Perovskite Film Hybridized with THz Metamaterials

In this work, we demonstrated a phonon-polariton in the terahertz (THz) frequency range, generated in a crystallized lead halide perovskite film coated on metamaterials. When the metamaterial resonance was in tune with the phonon resonance of the perovskite film, Rabi splitting occurred due to the strong coupling between the resonances. The Rabi splitting energy was about 1.1 meV, which is larger than the metamaterial and phonon resonance line widths; the interaction potential estimation confirmed that the strong coupling regime was reached successfully. We were able to tune the polaritonic branches by varying the metamaterial resonance, thereby obtaining the dispersion curve with a clear anticrossing behavior. Additionally, we performed in situ THz spectroscopy as we annealed the perovskite film and studied the Rabi splitting as a function of the films' crystallization coverage. The Rabi splitting versus crystallization volume fraction exhibited a unique power-law scaling, depending on the crystal growth dimensions.

Conjugation of arginylglycylaspartic acid to human serum albumin decreases the tumor-targeting effect of albumin by hindering its secreted protein acidic and rich in cysteine-mediated accumulation in tumors

Human serum albumin (HSA) accumulates in tumors by the enhanced permeability and retention (EPR) effect, which is a passive targeting effect in tumors. A recent study showed that secreted protein acidic and rich in cysteine (SPARC), an albumin-binding protein, mediates albumin accumulation in tumors. Arg-Gly-Asp (RGD) is a peptide targeting integrin α_vβ₃, which is highly expressed during tumor angiogenesis. We investigated whether conjugation of RGD to HSA could synergistically enhance tumor targeting. Accumulation of cRGDyK-HSA in integrin α_vβ₃-expressing SK-OV3 cells was observed by confocal microscopy. In SK-OV3 cells overexpressing the albumin binding protein SPARC, cellular uptake of HSA increased, but uptake of cRGDyK-HSA did not. cRGDyK-HSA showed decreased tumor accumulation compared with HSA by positron emission tomography (PET) scanning and biodistribution studies in an SK-OV3 xenograft mouse model. In SK-OV3 tumors, HSA accumulation colocalized with SPARC expression, while cRGDyK-HSA only accumulated in the outer region of the tumor, even though SPARC and integrin α_vβ₃ were expressed within the tumor core. We speculate that cRGDyK conjugation to HSA changes the characteristics of HSA and hinders its tumor-targeting effect. Therefore, HSA should be modified to preserve its native characteristics and enhance the tumor-targeting effects of HSA conjugates.

Akt1-Mediated Phosphorylation of RBP-Jk Controls Notch1 Signaling

The Notch1 signaling pathway plays a crucial role in determining cell fate, including cell growth and differentiation. In this study, we demonstrated that the antagonistic action of RTK (receptor tyrosine kinase) signaling pathway on the Notch1 signaling pathway is mediated via Ras-PI3K-Akt1. The PI3K-Akt1 signaling pathway was shown to inhibit Notch1 signaling via phosphorylation of RBP-Jk. We observed not only reduced association between Notch1 and RBP-Jk, but also suppression of the Notch1 transcriptional activity. Our results demonstrated that Akt1 functions as a natural inhibitor of the Notch1 signaling pathway via phosphorylation of RBP-Jk.

Light Intensity-dependent Variation in Defect Contributions to Charge Transport and Recombination in a Planar MAPbI3 Perovskite Solar Cell

We investigated operation of a planar MAPbI₃ solar cell with respect to intensity variation ranging from 0.01 to 1 sun. Measured J-V curves consisted of space-charge-limited currents (SCLC) in a drift-dominant range and diode-like currents in a diffusion-dominant range. The variation of power-law exponent of SCLC showed that charge trapping by defects diminished as intensity increased, and that drift currents became eventually almost ohmic. Diode-like currents were analysed using a modified Shockley-equation model, the validity of which was confirmed by comparing measured and estimated open-circuit voltages. Intensity dependence of ideality factor led us to the conclusion that there were two other types of defects that contributed mostly as recombination centers. At low intensities, monomolecular recombination occurred due to one of these defects in addition to bimolecular recombination to result in the ideality factor of ~1.7. However, at high intensities, another type of defect not only took over monomolecular recombination, but also dominated bimolecular recombination to result in the ideality factor of ~2.0. These ideality-factor values were consistent with those representing the intensity dependence of loss-current ratio estimated by using a constant internal-quantum-efficiency approximation. The presence of multiple types of defects was corroborated by findings from equivalent-circuit analysis of impedance spectra.

Biomarkers and new therapeutic targets in renal cell carcinoma

OBJECTIVE

Renal Cell Carcinoma (RCC) is the most common malignancy in adult kidneys. The American Cancer Society estimated 62,700 new cases and 14,240 deaths in 2018. Although early detection has improved in recent years, the treatment remains a challenge and reliable biomarkers for poor outcomes become necessary for the prevention of metastases and improve the quality of patients' life during and after treatment. Then, the current status of the search for new RCC biomarkers was discussed, as well as the latest discoveries in the RCC risk and metastatic treatment were discussed in this review.

MATERIALS AND METHODS

Extensive research was carried out in the online databases and full-free text articles published in the last 5 years, or more when convenient, were evaluated. Articles were included that addressed the proposed theme and were published in the English language.

RESULTS

The present state of knowledge on biomarkers for RCC carcinogenesis and progression is still much to be understood about RCC risk factors and molecular pathways resulting in metastatic progression. Newest RCC target therapies were discussed, mainly in relation to immunological therapy, and vaccines that have been tested in numerous trials with different cancer types.

CONCLUSIONS

The development of targeted therapies has revolutionized the treatment of advanced and metastatic cancers or non-responder patients. Combined therapy between classical chemotherapy and adjuvant immunotherapies has been modifying the cancer patients prognosis and bringing the hope of a cure in many cases.

Tunable broadband terahertz polarizer using graphene-metal hybrid metasurface

We demonstrate an electrically tunable polarizer for terahertz (THz) frequency electromagnetic waves formed from a hybrid graphene-metal metasurface. Broadband (>3 THz) polarization-dependent modulation of THz transmission is demonstrated as a function of the graphene conductivity for various wire grid geometries, each tuned by gating using an overlaid ion gel. We show a strong enhancement of modulation (up to ∼17 times) compared to graphene wire grids in the frequency range of 0.2-2.5 THz upon introduction of the metallic elements. Theoretical calculations, considering both plasmonic coupling and Drude absorption, are in good agreement with our experimental findings.

Inhibition of multiple voltage-gated calcium channels may contribute to spinally mediated analgesia by epipregnanolone in a rat model of surgical paw incision

Voltage-activated calcium channels play an important role in excitability of sensory nociceptive neurons in acute and chronic pain models. We have previously shown that low-voltage-activated calcium channels, or T-type channels (T-channels), increase excitability of sensory neurons after surgical incision in rats. We have also found that endogenous 5β-reduced neuroactive steroid epipregnanolone [(3β,5β)-3-hydroxypregnan-20-one] blocked isolated T-currents in dorsal root ganglion (DRG) cells in vitro, and reduced nociceptive behavior in vivo, after local intraplantar application into the foot pads of heathy rats and mice. Here, we investigated if epipregnanolone exerts an antinociceptive effect after intrathecal (i.t.) application in healthy rats, as well as an antihyperalgesic effect in a postsurgical pain model. We also studied if this endogenous neurosteroid blocks currents originating from high voltage-activated (HVA) calcium channels in rat sensory neurons. In in vivo studies, we found that epipregnanolone alleviated thermal and mechanical nociception in healthy rats after i.t. administration without affecting their sensory-motor abilities. Furthermore, epipregnanolone effectively reduced mechanical hyperalgesia after i.t application in rats after surgery. In subsequent in vitro studies, we found that epipregnanolone blocked isolated HVA currents in nociceptive sensory neurons with an IC₅₀ of 3.3 μM in a G-protein-dependent fashion. We conclude that neurosteroids that have combined inhibitory effects on T-type and HVA calcium currents may be suitable for development of novel pain therapies during the perioperative period.

Comparison of open and pneumovesical approaches for Politano-Leadbetter ureteric reimplantation: a single-center long-term follow-up study

PURPOSE

To report our experience with the laparoscopic pneumovesical approach for Politano-Leadbetter ureteric reimplantation and to compare the results to those obtained using a traditional open approach.

METHODS

We retrospectively reviewed the medical records of 52 patients who underwent Politano-Leadbetter ureteral reimplantation between 2012 and 2017. The peri-operative parameters, postoperative outcomes, and complication rates of patients who underwent the open approach for the Politano-Leadbetter procedure and those who underwent the laparoscopic pneumovesical approach were compared.

RESULTS

During the study period, 52 ureteric reimplantation procedures were analyzed. Among these, 28 and 24 patients underwent surgery using the open and pneumovesical approaches, respectively. The mean operative time did not differ between the groups (143.64 min vs. 128.12 min, P = 0.092). However, the pneumovesical group had a shorter duration of hospital stay (5.08 days vs 7.43 days, P = 0.001) and required less morphine analgesic for pain than did the open group (7.7% vs 32.1%, P = 0.027). No significant differences in the success rates (94.9% vs 92.5%, P = 0.512) or procedure-related complications were noted between the pneumovesical and open techniques.

CONCLUSIONS

The transvesicoscopic Politano-Leadbetter technique with pneumovesicum is safe and effective for ureteric reimplantation and is comparable to the open approach.

Highly Uniform Resistive Switching Performances Using Two-Dimensional Electron Gas at a Thin-Film Heterostructure for Conductive Bridge Random Access Memory

This research demonstrates, for the first time, the development of highly uniform resistive switching devices with self-compliance current for conductive bridge random access memory using two-dimensional electron gas (2DEG) at the interface of an Al₂O₃/TiO₂ thin-film heterostructure via atomic layer deposition (ALD). The cell is composed of Cu/Ti/Al₂O₃/TiO₂, where Cu/Ti and Al₂O₃ overlayers are used as the active/buffer metals and solid electrolyte, respectively, and the 2DEG at the interface of Al₂O₃/TiO₂ heterostructure, grown by the ALD process, is adopted as a bottom electrode. The Cu/Ti/Al₂O₃/TiO₂ device shows reliable resistive switching characteristics with excellent uniformity under a repetitive voltage sweep (direct current sweep). Furthermore, it exhibits a cycle endurance over 10⁷ cycles under short pulse switching. Remarkably, a reliable operation of multilevel data writing is realized up to 10⁷ cycles. The data retention time is longer than 10⁶ s at 85 °C. The uniform resistance switching characteristics are achieved via the formation of small (∼a few nm width) Cu filament with a short tunnel gap (<0.5 nm) owing to the 2DEG at the Al₂O₃/TiO₂ interface. The performance and operation scheme of this device may be appropriate in neuromorphic applications.

Abstract P2-08-53: Tumor elasticity and clinicopathologic factors affecting neoadjuvant chemotherapy response in breast cancer patients

Background: Neoadjuvant chemotherapy for breast cancer has been increased. Many studies have reported on clinicopathologic factors to predict neoadjuvant chemotherapy response. Elastography, which is usually used to differentiate benign and malignant tumors, can be performed to evaluate tissue elasticity during conventional ultrasonography. The purpose of this study was to determine the clinicopathologic factors, including tumor elasticity, that affect neoadjuvant chemotherapy response in stage II or III breast cancer patients.

Methods: From April 2014 to March 2017, 95 patients received neoadjuvant chemotherapy for clinical stage IIa-IIIc primary breast cancer. To evaluate tumor elasticity, strain elastography was performed in 74 patients before neoadjuvant chemotherapy. Patients were divided into two groups by the Tsukuba elasticity scoring system (soft group ≤3 vs. hard group ≥4). Histologic type, nuclear grade, tumor infiltrating lymphocytes (TILs), tumor cellularity, characteristics of stroma, and hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status were evaluated using core needle biopsy specimens obtained before neoadjuvant chemotherapy. Pathologic complete response (pCR) was defined as the absence of invasive carcinoma in breast (ypT0 and ypTis) and axillary lymph node (ypN0). Residual cancer burden (RCB) was also calculated in 79 cases and the cases were categorized into 2 groups; favorable RCB group (RCB-0 and I) and unfavorable RCB group (RCB-II and III).

Results: The mean age of patients was 46.43±8.62 years (range, 27-71 years) and the mean initial tumor size was 3.63±1.95cm (range, 2.1-12.8cm). Twenty-four patients (32.4%) were categorized into the soft group and 50 patients (67.6%) into the hard group. The mean tumor cellularity on core needle biopsy specimens and characteristics of stroma were not significantly different between the two groups (p=0.35 and p=0.79, respectively). Twenty-two patients achieved pCR (23.2%). The patients with pCR were more likely to have estrogen receptor (ER) or progesterone receptor (PR) negative breast cancer (p=0.04 and p=0.03). The rate of nuclear grade 3 was higher in patients with pCR than those without (p=0.03). Tumor elasticity was not correlated with pCR (p=0.28). Thirty patients (38.0%) achieved favorable RCB and forty-nine patients (62.0%) had unfavorable RCB. Not only the rates of ER negativity (p=0.05), PR negativity (p=0.03), nuclear grade 3 (p=0.01), and high TILs level (≥ 10%) (p=0.04) but also the mean TILs level (p=0.05) were significantly higher in the favorable RCB group compared withthe unfavorable RCB group. No significant difference in tumor elasticity was observed between the two groups (p=0.30). In univariate analyses, nuclear grade 3 (p=0.03), and high TILs level (≥10%) (p=0.04) were significantly correlated with favorable RCB. HR negativity was an independent predictor of favorable RCB in multivariate analysis (odds ratio, 2.93; 95% confidence interval, 1.04-8.28; p=0.04).

Conclusion: Tumor elasticity was not associated with pCR or RCB. HR negativity was an independent predictor for favorable RCB.Nuclear grade and TILs were also potential predictive factors for neoadjuvant chemotherapy response.

Citation Format: Park JY, Choi JE, Bae YK, Lee SJ. Tumor elasticity and clinicopathologic factors affecting neoadjuvant chemotherapy response in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-53.

Abstract P6-09-09: Analysis of serial circulating tumor cell count during neoadjuvant systemic therapy in breast cancer patients

Background: We aimed to evaluate the clinical implication of circulating tumor cell (CTC) counts in correlation with prognosis and radiologic/pathologic response to therapy in locally advanced breast cancer patients undergoing preoperative systemic therapy.

Methods: From Feb 2014 to May 2017, 207 patients without distant metastasis were prospectively enrolled from AMC. CTC counts were analyzed before-during-after the therapy. CTC isolation was performed using a SMART BIOPSY™ SYSTEM Isolation kit (Cytogen, Inc., Seoul, Korea). Recurrence-free and overall survival was analyzed according to CTC counts.

Result: The mean follow-up period was 22.46 months and mean age was 46.48 years. One or more CTC was identified in 132 of 203 patients(65.0%) before NST, in 135 of 186 patients(72.0%) during NST and 103 of 171 patients(60.2%) after NST. Initial tumor burden at diagnosis -tumor size, lymph node metastasis- was not correlated with CTC positivity. Overall, CTC count ((≥1 CTC, ≥2 CTCs, and ≥5 CTCs) was not correlated with response to therapy. Using RECIST criteria, 86.5% (179/204) were responders (complete, partial response, CR/PR) and 12.1% (25/204) were non-responders (stable, progressive disease, SD/PD). 14.5% (30/207) showed a pathologic complete response (pCR), yet no association was found between CTC count/changes and radiologic/pathologic response to therapy. Also, CTC count was not correlated with prognosis among the whole population. However, HR+ tumors, CTC detection before NST was significantly associated with treatment response by RECIST criteria (responder vs. non-responder) (p=0.003, p=0.017 and p=0.023, respectively).

Conclusions: Our findings support limited value of CTC count for locally advanced breast cancers undergoing neoadjuvant systemic therapy.

Citation Format: Gwark S-C, Kim J, Kim YH, Kim MS, Park JY, Lee SB, Sohn G, Chung IY, Ko BS, Kim HJ, Lee JW, Son BH, Ahn SH. Analysis of serial circulating tumor cell count during neoadjuvant systemic therapy in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-09.

Evolution and persistence of resistance-associated substitutions of hepatitis C virus after direct-acting antiviral treatment failures

Daclatasvir plus asunaprevir (DCV+ASV) treatment is an all-oral direct-acting antiviral (DAA) therapy for the genotype 1b HCV-infected patients. In this study, we investigated how resistance-associated substitutions (RASs) evolved after treatment failures and assessed the effect of those substitutions on viral fitness. Sequencing of NS5A and NS3 revealed typical RASs after treatment failures. Interestingly, the RASs of NS3 reverted to the wild-type amino acid within 1 year after treatment failures. However, the RASs of NS5A were stable and did not change. The effect of NS5A and NS3 RASs on viral RNA replication was assessed after mutagenic substitution in the genotype 1b HCV RNA. Among single substitutions, the effect of D168V was more substantial than the others and the effect of the triple mutant combination (D168V+L31V+Y93H) was the most severe. The RAS at NS5A Y93 affected both viral RNA replication and virus production. Finally, the effect of trans-complementation of NS5A was demonstrated in our co-transfection experiments and these results suggest that such a trans-complementation effect of NS5A may help maintain the NS5A RASs for a long time even after cessation of the DAA treatment. In conclusion, the results from this investigation would help understand the emergence and persistence of RASs.

Enhanced sensitivity in THz plasmonic sensors with silver nanowires

We developed hybrid slot antenna structures for microbial sensing in the THz frequency range, where silver nanowires (AgNWs) were employed to increase the sensitivity. In order to fabricate the hybrid devices, we partially etched the AgNW in the slot antenna region, where we can expect the field enhancement effect at the AgNW tip. We measured the resonant-frequency shift observed upon the deposition of a polymer layer, and observed that the sensitivity increased upon the introduction of AgNWs, with an enhancement factor of more than four times (approximately six times in terms of figure-of-merit). The sensitivity increased with the AgNW density until saturation. In addition, we tested devices with PRD1 viruses, and obtained an enhancement factor of 3.4 for a slot antenna width of 3 μm. Furthermore, we performed finite-difference time-domain simulations, which confirmed the experimental results. The sensitivity enhancement factor decreased with the decrease of the slot width, consistent with the experimental findings. Two-dimensional mapping of the electric field confirmed the strong field localization and enhancement at the AgNW tips.

Sarcopenia is associated with the risk of significant liver fibrosis in metabolically unhealthy subjects with chronic hepatitis B

BACKGROUND

Sarcopenia is significantly associated with the degree of liver fibrosis. This study investigated the influence of sarcopenia on liver fibrosis in individuals with chronic hepatitis B.

METHODS

Data from the Korean National Health and Nutrition Examination Surveys 2008-2011 were analysed. The sarcopenia index (total appendicular skeletal muscle mass [kg]/body mass index [kg/m² ]) was calculated using dual-energy X-ray absorptiometry. Sarcopenia was defined as the lowest quintile sarcopenia index value (cut-offs: 0.89 for men and 0.58 for women). The fibrotic burden was assessed using the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index. Significant fibrosis was defined as the highest nonalcoholic fatty liver disease fibrosis score quartile and a fibrosis-4 index ≥2.67.

RESULTS

Among the 506 respondents with chronic hepatitis B (258 men and 248 women), the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index identified sarcopenia and significant fibrosis in 126 (24.9%) and 217 (42.9%), respectively. Sarcopenia was significantly associated with significant fibrosis, regardless of the fibrosis prediction model used (all P < 0.05). When the study population was stratified according to metabolic factors, sarcopenia was specifically associated with an increased risk of significant fibrosis among subgroups with obesity, insulin resistance, metabolic syndrome and liver steatosis (odds ratio 2.37-3.57; all P < 0.05). An independent association between sarcopenia and significant fibrosis was identified after adjusting for other confounders (odds ratio 2.67-3.62 by the nonalcoholic fatty liver disease fibrosis score and 2.04-2.62 by the fibrosis-4 index; all P < 0.05).

CONCLUSIONS

Sarcopenia is associated with significant fibrosis in subjects with chronic hepatitis B, specifically those with obesity, insulin resistance, metabolic syndrome and liver steatosis.

Protein-Based Electronic Skin Akin to Biological Tissues

Human skin provides an interface that transduces external stimuli into electrical signals for communication with the brain. There has been considerable effort to produce soft, flexible, and stretchable electronic skin (E-skin) devices. However, common polymers cannot imitate human skin perfectly due to their poor biocompatibility, biofunctionality, and permeability to many chemicals and biomolecules. Herein, we report on highly flexible, stretchable, conformal, molecule-permeable, and skin-adhering E-skins that combine a metallic nanowire (NW) network and silk protein hydrogel. The silk protein hydrogels offer high stretchability and stability under hydration through the addition of Ca²⁺ ions and glycerol. The NW electrodes exhibit stable operation when subjected to large deformations and hydration. Meanwhile, the hydrogel window provides water and biomolecules to the electrodes (communication between the environment and the electrode). These favorable characteristics allow the E-skin to be capable of sensing strain, electrochemical, and electrophysiological signals.

Bronchial angles are associated with nodular bronchiectatic non-tuberculous mycobacteria lung disease

BACKGROUND

The nodular bronchiectatic (NB) form of non-tuberculous mycobacteria (NTM) lung disease usually involves the right middle lobe (RML) and the left upper lobe lingular segment. However, the reason underlying this preference is not known.

METHODS

Fifty patients with NB NTM lung disease who had both positive NTM culture(s) and NB lesions in the RML or lingular segment on computed tomography (CT) of the chest, and 100 healthy subjects matched for sex, age, height and body weight with normal chest CT, were randomly selected. Using reconstructed curved multiplanar reformation (MPR) images, the lengths, diameters and angles of the RML and lingular bronchi were measured.

RESULTS

Of the 150 individuals, 64% were female; the mean age was 55 years. The angles of the bronchi were significantly more acute in patients than in healthy subjects, both in the RML (patients, mean 46.75° ± standard deviation 8.87° vs. healthy subjects, mean 51.73° ± 7.76°; P = 0.001) and in the lingular segments (patients, mean 26.94° ± 8.16° vs. healthy subjects, mean 34.65° ± 9.75°; P < 0.001). In addition, the angles of the bronchi in the involved segments were more acute than those in the non-involved segments, both in the RML and the lingular segments. There were no differences in the lengths and bronchi diameters between groups.

CONCLUSIONS

An acute angle (obtuse slope) of RML/lingular bronchi could be an anatomical risk factor for NB NTM lung disease.

Predictors of failure to detect early hepatocellular carcinoma in patients with chronic hepatitis B who received regular surveillance

BACKGROUND

A proportion of chronic hepatitis B (CHB) patients are diagnosed with advanced hepatocellular carcinoma (HCC) despite regular surveillance.

AIMS

To determine predictors for HCC detection failure in CHB patients who underwent regular surveillance.

METHODS

CHB patients with well-preserved liver function, who underwent ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, were enrolled. Cox regression analysis was used to identify predictors for detection failure, defined as HCC initially diagnosed at Barcelona Clinic Liver Cancer (BCLC) stage B or C.

RESULTS

Of the 4590 CHB patients (mean age, 52.1 years; men, 61.6%), 169 patients were diagnosed with HCC (3.68%) and 35 (20.7%) HCC patients were initially diagnosed with HCC BCLC stage B or C. The cumulative incidence of HCC detection failure was 0.2% at year 1 and 1.3% at year 5. Multivariate analyses indicated that cirrhosis (hazard ratio [HR], 3.078; 95% CI, 1.389-6.821; P = 0.006), AFP levels ≥9 ng/mL (HR, 5.235; 95% CI, 2.307-11.957; P = 0.010), and diabetes mellitus (HR, 3.336; 95% CI, 1.341-8.296; P = 0.010) were independent predictors of HCC detection failure. Another model that incorporated liver stiffness (LS) values identified LS values ≥11.7 kPa (HR, 11.045; 95% CI, 2.066-59.037; P = 0.005) and AFP levels ≥9 ng/mL (HR, 4.802; 95% CI, 1.613-14.297; P = 0.005) as predictors of detection failure.

CONCLUSIONS

In CHB patients undergoing regular surveillance with ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, the HCC detection failure rate was not high (0.8% per person; 0.1% per test). However, careful attention should be paid in patients with advanced liver fibrosis (clinical cirrhosis or LS value >11.7 kPa), high AFP levels, or diabetes mellitus, who are prone to surveillance failure.