Understanding and controlling the nucleation and growth of metal-organic frameworks

Metal-organic frameworks offer a diverse landscape of building blocks to design high performance materials for implications in almost every major industry. With this diversity stems complex crystallization mechanisms with various pathways and intermediates. Crystallization studies have been key to the advancement of countless biological and synthetic systems, with MOFs being no exception. This review provides an overview of the current theories and fundamental chemistry used to decipher MOF crystallization. We then discuss how intrinsic and extrinsic synthetic parameters can be used as tools to modulate the crystallization pathway to produce MOF crystals with finely tuned physical and chemical properties. Experimental and computational methods are provided to guide the probing of MOF crystal formation on the molecular and bulk scale. Lastly, we summarize the recent major advances in the field and our outlook on the exciting future of MOF crystallization.

1295 CAN THE HOSPITAL FRAILTY RISK SCORE BE USED TO PREDICT POST-OPERATIVE OUTCOMES IN SPINAL SURGERY?

Introduction

Frailty is a syndrome associated with increasing numbers of elderly hospital admissions and prolonged inpatient stays (Archibald et al, Geriatrics, 2020, 20, 17). In 2015, an estimated 14% of inpatients in the UK were considered to have a degree of frailty, representing an approximate annual cost to the NHS of £5.8 billion (Soong et al, BMJ Open, 2015, 5, e008456; Han et al, Age and Aging, 2019, 48, 665-671). Frailty is poorly defined; there are discrepancies in existing literature on how to best quantify frailty. It is recognised there is a higher risk of adverse outcomes in this vulnerable population due to lack of physiological reserve (Clegg et al, The Lancet, 2013, 381, 752-762). The Hospital Frailty Risk Score (HFRS) is a recent development to measure frailty and identify patients at risk (Gilbert et al, The Lancet, 2018, 391, 1775-1782). This study sought to establish whether the HFRS could be used in patients with degenerative spinal disease, undergoing decompression surgery, to predict post-operative outcomes.

Methods

A retrospective service evaluation of eligible patients in Leeds Teaching Hospitals Trust between March 2018 - March 2020. The exposure was the patients’ HFRS; the outcome was the length of stay (LOS) until physiotherapy discharge. Data was sourced from electronic records.

Results

214 patients were identified with an available HFRS value. Patients were categorised as low, intermediate or high frailty. Kruskal-Wallis test for LOS and categorical HFRS: X2 =8.673, p<0.05. The median HFRS value was 1.25 (interquartile range 0.00 to 3.35). Mann-Whitney U test for LOS and numerical HFRS: W=29297, p<0.05.

Conclusions

The results of this study complement pre-existing studies of similar natures, evaluating frailty scoring and post-operative outcomes, thus, supporting the potential for standardised use of HFRS alongside holistic patient examination to streamline pre-assessment, improve outcomes and reduce the NHS frailty burden.

Role of Molecular Modification and Protein Folding in the Nucleation and Growth of Protein-Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are a class of porous nanomaterials that have been extensively studied as enzyme immobilization substrates. During in situ immobilization, MOF nucleation is driven by biomolecules with low isoelectric points. Investigation of how biomolecules control MOF self-assembly mechanisms on the molecular level is key to designing nanomaterials with desired physical and chemical properties. Here, we demonstrate how molecular modifications of bovine serum albumin (BSA) with fluorescein isothiocyanate (FITC) can affect MOF crystal size, morphology, and encapsulation efficiency. Final crystal properties are characterized using scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), fluorescent microscopy, and fluorescence spectroscopy. To probe MOF self-assembly, in situ experiments were performed using cryogenic transmission electron microscopy (cryo-TEM) and X-ray diffraction (XRD). Biophysical characterization of BSA and FITC-BSA was performed using ζ potential, mass spectrometry, circular dichroism studies, fluorescence spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. The combined data reveal that protein folding and stability within amorphous precursors are contributing factors in the rate, extent, and mechanism of crystallization. Thus, our results suggest molecular modifications as promising methods for fine-tuning protein@MOFs' nucleation and growth.

Evaluation of the GeneQuence® DNA Hybridization Method in Conjunction with 24-Hour Enrichment Protocols for Detection of Salmonella spp. in Select Foods: Collaborative Study

A multilaboratory study was conducted to compare performance of the GeneQuence® DNA hybridization (DNAH) method incorporating new 24 h enrichment protocols and reference culture procedures for detection of Salmonella spp. in select foods. Six food types (raw ground turkey, raw ground beef, dried whole egg, milk chocolate, walnuts, and dry pet food) were tested by the DNAH method and by the culture methods of either the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) or the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA/BAM). Fifteen laboratories participated in the study. Four of the foods tested (raw ground turkey, dried whole egg, milk chocolate, and dry pet food), showed no statistically significant differences in performance between the DNAH method and the reference procedure as determined by Chi square analysis. Sensitivity rates for the DNAH method ranged from 92 to 100. The DNAH method, with the specific enrichment protocol evaluated, was found to be ineffective for detection of Salmonella spp. in walnuts. For raw ground beef, results from one trial showed a statistically significant difference in performance, with more positives obtained by the reference method. However, evidence suggests that the difference in the number of positives was likely due to lack of homogeneity of the test samples rather than to DNAH method performance.

Differentiation of Hemorrhage from Iodine Using Spectral Detector CT: A Phantom Study

BACKGROUND AND PURPOSE

Conventional CT often cannot distinguish hemorrhage from iodine extravasation following reperfusion therapy for acute ischemic stroke. We investigated the potential of spectral detector CT in differentiating these lesions.

MATERIALS AND METHODS

Centrifuged blood with increasing hematocrit (5%-85%) was used to model hemorrhage. Pure blood, blood-iodine mixtures (75/25, 50/50, and 25/75 ratios), and iodine solutions (0-14 mg I/mL) were scanned in a phantom with attenuation ranging from 12 to 75 HU on conventional imaging. Conventional and virtual noncontrast attenuation was compared and investigated for correlation with calculation of relative virtual noncontrast attenuation. Values for all investigated categories were compared using the Mann-Whitney U test. Sensitivity and specificity of virtual noncontrast, relative virtual noncontrast, conventional CT attenuation, and iodine quantification for hemorrhage detection were determined with receiver operating characteristic analysis.

RESULTS

Conventional image attenuation was not significantly different among all samples containing blood (P > .05), while virtual noncontrast attenuation showed a significant decrease with a decreasing blood component (P < .01) in all blood-iodine mixtures. Relative virtual noncontrast values were significantly different among all investigated categories (P < .01), with correct hemorrhagic component size estimation for all categories within a 95% confidence interval. Areas under the curve for hemorrhage detection were 0.97, 0.87, 0.29, and 0.16 for virtual noncontrast, relative virtual noncontrast, conventional CT attenuation, and iodine quantification, respectively. A ≥10-HU virtual noncontrast, ≥20-HU virtual noncontrast, ≥40% relative virtual noncontrast, and combined ≥10-HU virtual noncontrast and ≥40% relative virtual noncontrast attenuation threshold had a sensitivity/specificity for detecting hemorrhage of 100%/23%, 89%/95%, 100%/82%, and 100%/100%, respectively.

CONCLUSIONS

Spectral detector CT can accurately differentiate blood from iodinated contrast in a phantom setting.

Compact multichannel high-resolution micro-electro-mechanical systems-based interrogator for Fiber Bragg grating sensing

We propose a novel type of compact high-resolution multichannel micro-electro-mechanical systems (MEMS)-based interrogator, where we replace the linear detector with a digital micromirror device (DMD). The DMD is typically cheaper and has better pixel sampling than an InGaAs detector used in the 1550 nm range, which leads to cost reduction and better performance. Moreover, the DMD is a 2D array, which means that multichannel systems can be implemented without any additional optical components in the interrogator. This makes the proposed interrogator highly cost-effective, particularly for multichannel systems. The digital nature of the DMD also provides opportunities for advanced programmable Hadamard spectroscopy, which, without significant penalties, can greatly improve the wavelength fit resolution. Our results show that DMDs can be used in high-resolution spectroscopy and for Fiber Bragg grating (FBG) interrogation.

Performance of low-cost few-mode fiber Bragg grating sensor systems: polarization sensitivity and linearity of temperature and strain response

We evaluate whether 850 nm fiber Bragg grating (FBG) sensor systems can use low-cost 1550 nm telecom fibers; in other words, how detrimental the influence of higher-order modes is to the polarization stability and linearity of the strain and temperature response. We do this by comparing polarization sensitivity of a few-mode 850 nm FBG sensor to a strictly single-mode 850 nm FBG sensor system using 850 nm single-mode fibers. We also compare the performance of the FBGs in strain and temperature tests. Our results show that the polarization stability and the linearity of the response degrade due to the presence of the higher-order modes. We demonstrate that, by using simple coiling of the 1550 nm fiber, one can regain the performance of the few-mode system and make it usable for high precision measurements.

Cervical human papillomavirus infections in commercial sex workers—risk factors and behaviours

We have investigated the prevalence of, and risk factors for, cervical human papillomavirus (HPV) infection in commercial sex workers (CSWs) and controls attending the same sexual health clinics in Sydney. A self-administered 'risk factor' questionnaire was completed and a Pap smear and a specimen for HPV detection and typing were taken. Results from the 288 CSWs and 266 controls were assessed by univariate and multivariate analyses. No significant difference in the rates of cervical HPV infection in CSWs (31.6%) and controls (24.4%) was found but HPV related cytological abnormalities were more common on the CSWs ( P <0.05). In both groups, factors independently associated with HPV infection were the use of non-barrier contraception, cytological abnormalities, age under 36 and the number of non-paying sexual partners. A risk factor for CSWs only was sex-work in Japan. A detailed 'work' history from CSWs may be useful to identify unsafe practices or work in countries where safer sex may be less acceptable.

Demonstrating correction of low levels of astigmatism with realistic scenes

PURPOSE AND METHOD

Modern standard visual acuity tests are primarily designed as diagnostic tools for use during subjective refraction and normally bear little relation to real-world situations. We have developed a methodology to create realistic rendered scenes that demonstrate potential vision improvement in a relevant and engaging way. Low-cylindrical refractive error can be made more noticeable by optimizing the contrast and spatial frequencies, and by testing four different visual perception skills: motion tracking, pattern recognition, visual clutter differentiation and contrast sensitivity. Using a 1.00DC lens during iteration, we created a range of still and video scenes before optimizing to a selection 3-D rendered street scenes. These were assessed on everyday relevance, emotional and visual engagement and sensitivity to refractive correction for low-cylinder astigmats (0.75-1.00DC, n=74) wearing best spherical equivalent correction and then with astigmatism corrected.

RESULTS AND CONCLUSIONS

The most promising visual elements involved or combined optimized textures, distracting patterns behind text, faces at a distance, and oblique text. 91.9% of subjects (95% CI: 83.2, 97.0) reported an overall visual improvement when viewing the images with astigmatic correction, and 96% found the images helpful to determine which type of contact lens to use. Our method, which combines visual science with design thinking, takes a new approach to creating vision tests. The resultant test scenes can be used to improve patient interaction and help low cylinder astigmats see relevant, every-day benefits in correcting low levels (0.75 & 1.00DC) of astigmatism.

Dynamic gate algorithm for multimode fiber Bragg grating sensor systems

We propose a novel dynamic gate algorithm (DGA) for precise and accurate peak detection. The algorithm uses a threshold-determined detection window and center of gravity algorithm with bias compensation. We analyze the wavelength fit resolution of the DGA for different values of the signal-to-noise ratio and different peak shapes. Our simulations and experiments demonstrate that the DGA method is fast and robust with better stability and accuracy than conventional algorithms. This makes it very attractive for future implementation in sensing systems, especially based on multimode fiber Bragg gratings.

Intercellular communication and some structural aspects of membrane junctions in a simple cell system

AChironomus salivary gland consists of a chain of 30 giant cells (G-cells) and 4 to 6 flat cells (F-cells) spanning a lumen. The surface membranes of these cells are linked by two kinds of organized structures: theseptate junction, taking up nearly the entire surface of cell contact, and thegap junction, occupying a small fraction of this surface. (These junctional structures are examined in the electron microscope after La infiltration.) All cells are joined to their immediate neighbors by septate junctions, the G- to G-cells, the F- to F-cells, and the F- to G-cells; the G-cells, at least, are also joined by gap junctions. All cells are also in communication with each other: small inorganic ions, fluorescein (mol. wt. 330) and Procion Yellow (mol. wt. ∼550) pass from one cell interior to the next.

Bipartite talus: a case series and algorithm for treatment

BACKGROUND

Bipartite talus is a rare condition of uncertain aetiology, with various treatment options described.

METHODS

We report five symptomatic bipartite talus cases in four male patients warranting surgical management. All patients were reviewed by an independent assessor.

RESULTS

The youngest patient presented with bilateral lesions without sub-talar arthrosis. He was treated twice by internal fixation with bone grafting. The left side failed to unite. The second patient presented with isolated sub-talar osteoarthritis. He underwent fragment excision and sub-talar arthrodesis with bone graft. The third patient presented aged 55 with severe hind-foot osteoarthritis, and underwent tibio-talar-calcaneal fusion. The final patient was treated with fragment excision and sub-talar arthrodesis. All patients reported symptom improvement or resolution post-operatively. Four cases showed evidence of radiographic union.

CONCLUSIONS

We suggest a treatment rationale of fragment fusion if large enough, or excision if not, with associated limited fusion if the adjacent joints are markedly degenerate.

Human papillomavirus modifies the prognostic significance of T stage and possibly N stage in tonsillar cancer

BACKGROUND

Despite the association with more advanced nodal stage, patients with human papillomavirus (HPV) positive oropharyngeal cancers have better outcomes. We examined whether the HPV can modify the effect of known prognostic factors in tonsillar cancer.

PATIENTS AND METHODS

A total of 489 patients from 10 centres were followed up for recurrence or death for a median of 3.2 years. Determinants of the rate of locoregional recurrence, death from tonsillar cancer and overall survival were modelled using Cox regression.

RESULTS

The prognostic value of T and N stages were modified by HPV as indicated by statistically significant interaction terms. After adjusting for age, gender and treatment, T stage appeared relevant only for HPV-positive cancers (where a higher T stage was associated with worse outcomes). There was some evidence that N stage was a more relevant prognostic factor for HPV-negative than -positive cancers. There was no evidence that the HPV modifies the effect of age, gender or grade on outcomes.

CONCLUSIONS

This study suggests that the prognostic significance of the conventional staging system in tonsillar cancer is modified by HPV.

Type 3 secretion system effector genotype and secretion phenotype of longitudinally collected Pseudomonas aeruginosa isolates from young children diagnosed with cystic fibrosis following newborn screening

Studies of the type 3 secretion system (T3SS) in Pseudomonas aeruginosa isolates from chronically infected older children and adults with cystic fibrosis (CF) show a predominantly exoS+/exoU- (exoS+) genotype and loss of T3SS effector secretion over time. Relatively little is known about the role of the T3SS in the pathogenesis of early P. aeruginosa infection in the CF airway. In this longitudinal study, 168 P. aeruginosa isolates from 58 children diagnosed with CF following newborn screening and 47 isolates from homes of families with or without children with CF were genotyped by pulsed-field gel electrophoresis (PFGE) and T3SS genotype and phenotype determined using multiplex PCR and western blotting. Associations were sought between T3SS data and clinical variables and comparisons made between T3SS data of clinical and environmental PFGE genotypes. Seventy-seven of the 92 clinical strains were exoS+ (71% secretors (ExoS+)) and 15 were exoU+ (93% secretors (ExoU+)). Initial exoS+ strains were five times more likely to secrete ExoS than subsequent exoS+ strains at first isolation. The proportion of ExoS+ strains declined with increasing age at acquisition. No associations were found between T3SS characteristics and gender, site of isolation, exacerbation, a persistent strain or pulmonary outcomes. Fourteen of the 23 environmental strains were exoS+ (79% ExoS+) and nine were exoU+ (33% ExoU+). The exoU+ environmental strains were significantly less likely to secrete ExoU than clinical strains. This study provides new insight into the T3SS characteristics of P. aeruginosa isolated from the CF airway early in life.

Decreased neuronal Na+, K+ -ATPase activity in Atp1a3 heterozygous mice increases susceptibility to depression-like endophenotypes by chronic variable stress

Unipolar depression and bipolar depression are prevalent and debilitating diseases in need of effective novel treatments. It is becoming increasingly evident that depressive disorders manifest from a combination of inherited susceptibility genes and environmental stress. Genetic mutations resulting in decreased neuronal Na(+) ,K(+) -ATPase (sodium-potassium adenosine triphosphatase) activity may put individuals at risk for depression given that decreased Na(+) ,K(+) -ATPase activity is observed in depressive disorders and animal models of depression. Here, we show that Na(+) ,K(+) -ATPase α3 heterozygous mice (Atp1a3(+/-) ), with 15% reduced neuronal Na(+) ,K(+) -ATPase activity, are vulnerable to develop increased depression-like endophenotypes in a chronic variable stress (CVS) paradigm compared to wild-type littermates (Atp1a3(+/+) ). In Atp1a3(+/+) mice CVS did not decrease Na(+) ,K(+) -ATPase activity, however led to despair-like behavior in the tail suspension test (TST), anhedonia in a sucrose preference test and a minimal decrease in sociability, whereas in Atp1a3(+/-) mice CVS decreased neuronal Na(+) ,K(+) -ATPase activity to 33% of wild-type levels, induced despair-like behavior in the TST, anhedonia in a sucrose preference test, anxiety in the elevated plus maze, a memory deficit in a novel object recognition task and sociability deficits in a social interaction test. We found that a mutation that decreases neuronal Na(+) ,K(+) -ATPase activity interacts with stress to exacerbate depression. Furthermore, we observed an interesting correlation between Na(+) ,K(+) -ATPase activity and mood that may relate to both unipolar depression and bipolar disorder. Pharmaceuticals that increase Na(+) ,K(+) -ATPase activity or block endogenous Na(+) , K(+) -ATPase inhibition may provide effective treatment for depressive disorders and preclude depression in susceptible individuals.

Masitinib as a chemosensitizer of canine tumor cell lines: a proof of concept study

Masitinib, a selective tyrosine kinase inhibitor, has previously been shown to enhance the antiproliferative effects of gemcitabine in human pancreatic cancer, demonstrating potential as a chemosensitizer. This exploratory study investigated the ability of masitinib to sensitize various canine cancer cell lines to doxorubicin, vinblastine, and gemcitabine. Masitinib strongly sensitized histiocytic sarcoma cells to vinblastine (>70-fold reduction in IC(50) at 5 μM masitinib), as well as osteosarcoma and mammary carcinoma cells to gemcitabine (>70-fold reduction at 5-10 μM). In addition, several cell lines were sensitized to doxorubicin (2-10-fold reduction at 10 μM). These data establish proof-of-concept that masitinib in combination with chemotherapeutic agents can generate synergistic growth inhibition in various canine cancers, possibly through chemosensitization. The findings justify further investigation into those combinations that may potentially yield therapeutic benefit.

Measured concentrations of combustion gases from the use of unvented gas fireplaces

Measurements of combustion product concentrations were taken in 30 homes where unvented gas fireplaces were used. Measurements of CO, CO(2), NO(x), NO(2) , O(2) (depletion), and water vapor were taken at 1-min interval. The analyzers were calibrated with certified calibration gases for each placement and were in operation for 3-4 days at each home. Measured concentrations were compared to published health-based standards and guidelines. The two combustion gases that exceeded published values were NO(2) and CO. For NO(2) , the Health Canada guideline of 250 ppb (1-h average) was exceeded in about 43% of the sample and the World Health Organization (WHO) guideline of 110 ppb (1-h average) was exceeded in 80% of the sample. Carbon monoxide levels exceeded the U.S. EPA 8-h average standard of 9 ppm in 20% of the sample. Moisture problems were not evident in the test homes. An analysis of the distribution of CO showed that the CO is dispersed throughout the home almost immediately upon operation of the fireplace and that the concentrations throughout the home away from the immediate vicinity of the fireplace are 70-80% of the level near the fireplace. Decay analysis of the combustion gases showed that NO was similarly stable to CO and CO(2) in the indoor environment but that both NO(2) and water vapor were removed from the air at much greater rates.

PRACTICAL IMPLICATIONS

Previous studies on unvented gas fireplaces have made assumptions of how they are operated by users. This article presents the results of field monitoring of 30 unvented gas fireplaces under normal operation, regardless of whether users follow industry recommendations regarding installation, usage patterns, and maintenance. The monitoring found that health-based standards and guidelines were exceeded for CO in 20% of homes and for NO(2) in most homes. There were no identified moisture problems in these homes. Nearly, half of the fireplaces were used at least once for longer than 2 h, counter to manufacturers' intended usage as supplemental heating. This demonstrates that given actual usage patterns and compared to current health-based thresholds, these appliances can produce indoor air concentrations considered to be unhealthy to at least sensitive or at-risk individuals.

Multiple endocrine adenomatosis of mixed type

A case of multiple endocrine adenomatosis (MEA) of mixed type is presented. The syndrome, observed in a 65 year-old female, consisted of multiple neurofibroadenomatosis, medullary thyroid carcinoma, multiple adenomata of the parathyroids, adrenal cortical adenoma and small cell anaplastic bronchogenic carcinoma. Thus, it was composed of type 1 as well as of type 2 MEA. On the basis of another seven cases, collected from the literature, the MEA syndrome of mixed type is reviewed with special reference to the phylogenetic origin of the cells of the APUD system.

Effects of somatostatin and octreotide on cytokine and chemokine production by lipopolysaccharide-activated peripheral blood mononuclear cells

BACKGROUND

Somatostatin plays an important role in the communication between the nervous, endocrine, and immune systems. Although somatostatin or its analogues have been shown to modulate a number of immune functions, their immunomodulatory effects are not uniform and are strongly dependent on the underlying cell system.

AIM

The aim of our study was to analyze the immunomodulatory effects of somatostatin and its analogue octreotide on peripheral blood mononuclear cells (PBMC) in vitro. MATERIALS/SUBJECTS:We used lipopolysaccharide-activated cells from normal glucose tolerant (NGT) subjects and from Type 2 diabetes mellitus (T2DM) patients as T2DM is associated with chronic, low-grade inflammation, and measured immune mediator release with multiplex bead-based assays.

RESULTS

Our data showed no statistically significant effects on the secretion of the cytokines interleukin (IL)-1beta, IL-6, IL-10, IL-12, interferon-gamma and tumor necrosis factor-alpha as well as the chemokines IL-8 and monocyte chemoattractant protein (MCP)-1, either on PBMC from T2DM patients or on those from NGT controls. However, a trend towards a dose-dependent biphasic effect was observed for IL- 6, IL-10 and MCP-1 with reduced immune mediator levels at low and increased/unaltered levels at higher somatostatin or octreotide concentrations. These observations could not be explained by interference with cell viability or proliferation.

CONCLUSIONS

We could not confirm immunomodulatory properties of somatostatin and octreotide on PBMC. Further analyses are necessary to explain the interaction between neuropeptides and the immune system.

Vaspin (SERPINA12) genotypes and risk of type 2 diabetes: Results from the MONICA/KORA studies

Vaspin has recently been identified as novel adipokine with high expression in adipose tissue of obese and type 2 diabetic subjects and with potentially insulin-sensitising properties. However, the impact of vaspin gene variants on the risk of type 2 diabetes mellitus (T2DM) has not been determined yet. Therefore, the aim of our study was to investigate the association of vaspin single nucleotide polymorphisms (SNPs) with T2DM and obesity. We analysed the association between 25 vaspin SNPs and T2DM in initially healthy 35-84 year-old individuals of the population-based, cross-sectional German KORA F3 study and assessed the association with measures of obesity. Genotyping was carried out with matrix-assisted laser desorption/ionisation-time of flight mass spectrometry of allele-dependent primer extension products and associations with T2DM and obesity were analysed by logistic regression analysis. Our results demonstrate a significant association of vaspin SNP rs2236242 with T2DM in the KORA F3 study with the AA genotype bearing an increased risk (adjusted OR 2.35 [1.59; 3.46] versus AT/TT). This association appears to be independent of obesity. Our finding corroborates previous studies that suggested a link between the novel adipokine vaspin and glucose metabolism.