Hepatic Artery Aneurysm/Pseudoaneurysm: An Unusual Cause of Upper Gastrointestinal (UGI) Bleeding and Biliary Obstruction Further Complicated by Glue Dislodgement Leading to Biliary Obstruction.

Hepatic artery aneurysms (HAA) and pseudoaneurysms are rare vascular abnormalities, that can lead to significant morbidity and mortality if left untreated. We present a case report of a 78-year-old lady with a hepatic artery aneurysm who initially presented with upper gastrointestinal bleeding (UGIB) and biliary obstruction and was treated by trans-arterial embolization. Recovery was complicated by glue embolisation leading to obstructive jaundice and biliary sepsis. This case highlights the importance of having a high index of suspicion for HAA and pseudoaneurysm when initial investigations including oesophago gastro duodenoscopy (OGD) are negative. Although rare, glue embolization should be considered in patients who present with obstructive jaundice and abdominal pain.

A High Pressure Operando Spectroscopy Examination of Bimetal Interactions in 'Metal Efficient' Palladium/In2 O3 /Al2 O3 Catalysts for CO2 Hydrogenation.

CO2 hydrogenation to methanol has the potential to serve as a sustainable route to a wide variety of hydrocarbons, fuels and plastics in the quest for net zero. Synergistic Pd/In2 O3 (Palldium on Indium Oxide) catalysts show high CO2 conversion and methanol selectivity, enhancing methanol yield. The identity of the optimal active site for this reaction is unclear, either as a Pd-In alloy, proximate metals, or distinct sites. In this work, we demonstrate that metal-efficient Pd/In2 O3 species dispersed on Al2 O3 can match the performance of pure Pd/In2 O3 systems. Further, we follow the evolution of both Pd and In sites, and surface species, under operando reaction conditions using X-ray Absorption Spectroscpy (XAS) and infrared (IR) spectroscopy. In doing so, we can determine both the nature of the active sites and the influence on the catalytic mechanism.

Sputum Color as a Marker for Bacteria in Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis.

Rationale: Diagnosing bacterial infection as the etiology in acute exacerbations of chronic obstructive pulmonary disease (AECOPDs) remains challenging. Sputum discoloration is easily measured and often used as a marker of bacterial infection in AECOPD, although high-quality evidence for this practice is lacking. Objectives: To determine the diagnostic accuracy of sputum color as a marker for bacteria in AECOPD. Methods: Articles were searched for in electronic databases, and the gray literature were reviewed. Quality assessment of included articles was performed using the revised Quality Assessment of Diagnostic Accuracy Studies tool. A meta-analysis was conducted using a bivariate logistic regression model with random effects. Analysis was conducted on individual sputum samples rather than on individual participants so that each sample represented a unique index test. Results: Of the 1,600 candidate studies, 13 eligible studies satisfied the inclusion criteria. These included prospective cohort studies (n = 3), cross-sectional studies (n = 3), and secondary analyses of randomized controlled trials (n = 7). The included studies were all from Europe and North America. Most studies scored high risk of bias in at least one domain. In total, this systematic review and meta-analysis included 5,770 sputum samples. The estimated pooled sensitivity and specificity were 81% (95% confidence interval [CI], 70-88%) and 50% (95% CI, 35-65%), respectively, and these results were not significantly altered in a series of sensitivity analyses. Conclusions: Sputum color has limited value as a stand-alone test in diagnosing bacterial infection as the etiology in AECOPD because of its moderate sensitivity and poor specificity.

Combined spectroscopic and computational study for optimising catalyst design in hydrocarbon transformations.

Molecular interactions of hydrocarbons within the confined pores of heterogeneous catalysts can influence reaction pathways, which play a crucial role in determining the overall efficacy of catalytic transformations. We probe the interactions of n-butane with a solid-acid zeolite, mordenite, combining inelastic neutron scattering with DFT calculations. This reveals that the solid-acid sites within mordenite induce a conformer change, which could be key in designing optimised catalysts, for hydrocarbon transformations.

SARS-CoV-2 infection in public hospital medical doctors in an Eastern Cape metro.

Background: Evidence-based Infection Prevention and Control (IPC) measures are critical in protecting medical doctors from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Concerns surrounding access to personal protective equipment (PPE), compliance with IPC measures and the quality of available PPE have been raised as possible causes for high rates of SARS-CoV-2 infection in medical doctors in high transmission settings. This study aimed to determine the prevalence of SARS-CoV-2 infection and the risk factors for occupational infection in doctors in the hospitals in Nelson Mandela Bay (NMB). Methods: We conducted a cross-sectional study wherein we electronically surveyed medical doctors in public-sector NMB hospitals from 01 March 2020 to 31 December 2020. We collected demographic, health, occupational and SARS-CoV-2 infection and exposure data. Categorical data were described as proportions and a multiple variable logistic regression model was used to identify risk factors for SARS-CoV-2 infection. Results: The survey was distributed amongst 498 doctors, 141 (28%) of whom replied. Forty-three (31%) participants reported that they had tested positive for SARS-CoV-2 during the study period. Eighty-nine participants (64%) reported inadequate access to PPE whilst only 68 (49%) participants adhered to PPE recommendations when interacting with patients with confirmed or suspected SARS-CoV-2 infection. We were unable to identify any significant predictors of SARS-CoV-2 infection. Conclusion: This study demonstrates a high prevalence of SARS-CoV-2 infection in public hospital doctors in NMB. Most participants reported inadequate access to PPE and poor compliance with IPC protocols. These findings suggest an urgent need for the improved implementation of IPC measures to protect doctors from SARS-CoV-2 infection.

Characterization of Differentially Expressed miRNAs by CXCL12/SDF-1 in Human Bone Marrow Stromal Cells.

Stromal cell-derived factor 1 (SDF-1) is known to influence bone marrow stromal cell (BMSC) migration, osteogenic differentiation, and fracture healing. We hypothesize that SDF-1 mediates some of its effects on BMSCs through epigenetic regulation, specifically via microRNAs (miRNAs). MiRNAs are small non-coding RNAs that target specific mRNA and prevent their translation. We performed global miRNA analysis and determined several miRNAs were differentially expressed in response to SDF-1 treatment. Gene Expression Omnibus (GEO) dataset analysis showed that these miRNAs play an important role in osteogenic differentiation and fracture healing. KEGG and GO analysis indicated that SDF-1 dependent miRNAs changes affect multiple cellular pathways, including fatty acid biosynthesis, thyroid hormone signaling, and mucin-type O-glycan biosynthesis pathways. Furthermore, bioinformatics analysis showed several miRNAs target genes related to stem cell migration and differentiation. This study's findings indicated that SDF-1 induces some of its effects on BMSCs function through miRNA regulation.

Thiol Functionalised Supports for Controlled Metal Nanoparticle Formation for Improved C-C Coupling.

The myriad applications of metal nanoparticle systems have individual demands on their size, shape and electronic states, demanding novel synthetic methods to optimise these properties. Herein we report our method of exploiting strong thiol-Pd binding as a precursor for forming small, uniform Pd nanoparticles on activation. We validate our approach with a range of characterisation techniques and contrast our design strategy with an analogous wetness impregnation method, showing the drastic improvements for catalytic C-C coupling. The presence of the thiol groups offers greater control over nanoparticle formation, particularly temperature resolution on activation, potentially allowing more targeted nanoparticle formation procedures.

Sputum colour as a marker for bacteria in acute exacerbations of COPD: protocol for a systematic review and meta-analysis.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major cause of years of life lost globally. Acute exacerbations of COPD (AECOPD) drive disease progression, reduce quality of life and are a source of mortality in COPD. Approximately 50% of AECOPD are due to bacterial infections. Diagnosing bacterial infection as the aetiology of AECOPD however remains challenging as investigations are limited by practicality, accuracy and expense. Clinicians have traditionally used sputum colour as a marker of bacterial infection in AECOPD, despite the lack of high-quality evidence for this practice. The aim of this systematic review and meta-analysis is to determine the diagnostic accuracy of sputum colour in the diagnosis of bacterial causes of AECOPD. METHODS: Articles will be searched for in electronic databases (MEDLINE, Google Scholar Scopus, Web of Science, Africa-Wide, CINAHL and Health Source Nursing Academy) and we will conduct a review of citation indexes and the grey literature. Two reviewers will independently conduct study selection, against pre-defined eligibility criteria, data extraction and quality assessment of included articles using the QUADAS-2 tool. We will perform a meta-analysis using a bivariate logistic regression model with random effects. We will explore heterogeneity through the visual examination of the forest plots of sensitivities and specificities and through the inclusion of possible sources of heterogeneity as covariates in a meta-regression model if sufficient studies are included in the analysis. We also perform a sensitivity analysis to explore the effect of study quality on our findings. The results of this review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement and will be submitted for peer-review and publication. DISCUSSION: The findings of this review will assist clinicians in diagnosing the aetiology of AECOPD and may have important implications for decision making in resource-limited settings, as well as for antimicrobial stewardship. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019141498.

Absence of Nanoparticle-Induced Drought Tolerance in Nutrient Sufficient Wheat Seedlings.

Strategies to reduce crop losses due to drought are needed as climate variability affects agricultural productivity. Wheat (Triticum aestivum var. Juniper) growth in a nutrient-sufficient, solid growth matrix containing varied doses of CuO, ZnO, and SiO2 nanoparticles (NPs) was used to evaluate NP mitigation of drought stress. NP amendments were at fertilizer levels, with maxima of 30 Cu, 20 Zn, and 200 Si (mg metal/kg matrix). Seeds of this drought-tolerant cultivar were inoculated with Pseudomonas chlororaphis O6 (PcO6) to provide a protective root microbiome. An 8 day drought imposed on 14 day-old wheat seedlings decreased shoot and root mass, shoot water content, and the quantum yield of photosystem II when compared to watered plants. PcO6 root colonization was not impaired by drought or NPs. A dose-dependent increase in the Cu, Zn, and Si from the NPs was observed from analysis of the rhizosphere solution, and this process was not affected by drought. Consequently, fertilizer concentrations of the NPs did not further improve drought tolerance in wheat seedlings under the growth conditions of adequate mineral nutrition and the presence of a beneficial microbiome. These findings suggest that potential NP benefits in promoting plant drought tolerance occur only under certain environmental conditions.

Understanding catalytic CO2 and CO conversion into methanol using computational fluid dynamics.

The kinetics of methanol synthesis from a mixture of CO2/CO/H2 have been widely studied in the literature. Yet the role of direct CO hydrogenation is still unclear, in terms of predicting and developing an accurate kinetic model. To investigate, a computational fluid dynamics model has been developed, incorporating two distinct kinetic models, one which includes CO hydrogenation and one which does not. Including CO hydrogenation in the kinetic model provides a more complex interaction between the three involved reactions and can better predict potential inhibitions caused by the presence of H2O. This, however, increases the complexity of the kinetic model. The benefit of applying a fluid dynamics model to study fixed bed reactors is demonstrated, as it offers unique insights into the spatial species concentration, temperature variations, and reaction rate magnitudes. The validated model is shown to be a powerful interrogative tool, capable of supporting system optimization across the catalyst and reactor engineering sectors.

Bimetallic PdAu Catalysts within Hierarchically Porous Architectures for Aerobic Oxidation of Benzyl Alcohol.

Hierarchically porous (HP) zeotype materials (possessing both micropores and mesopores) offer improved diffusional access to intra-framework active sites, analogous to mesoporous materials, yet retain the high selectivity of the microporous (MP) bulk. We have recently designed crystalline hierarchically porous silicoaluminophosphates (SAPOs) with enhanced mass-transport characteristics, which can lead to significant improvement in catalytic activity and catalyst lifetime. In this study, we have prepared PdAu bimetallic nanostructures supported on HP-SAPO frameworks by an incipient impregnation of metal precursors followed by H2 reduction at 300 °C, for the aerobic oxidation of benzyl alcohol to benzaldehyde. PdAu NPs supported on HP framework displayed significantly enhanced catalytic activities, when compared with their MP analogues, clearly highlighting the benefits of introducing hierarchical porosity in the SAPO support matrix.

Kynurenine induces an age-related phenotype in bone marrow stromal cells.

Advanced age is one of the important contributing factors for musculoskeletal deterioration. Although the exact mechanism behind this degeneration is unknown, it has been previously established that nutritional signaling plays a vital role in musculoskeletal pathophysiology. Our group established the vital role of the essential amino acid, tryptophan, in aging musculoskeletal health. With advanced age, inflammatory factors activate indoleamine 2,3-dioxygenase (IDO1) and accumulate excessive intermediate tryptophan metabolites such as Kynurenine (KYN). With age, Kynurenine accumulates and suppresses osteogenic differentiation, impairs autophagy, promotes early senescence, and alters cellular bioenergetics of bone marrow stem cells. Recent studies have shown that Kynurenine negatively impacts bone marrow stromal cells (BMSCs) and, consequently, promotes bone loss. Overall, understanding the mechanism behind BMSCs losing their ability for osteogenic differentiation can provide insight into the prevention of osteoporosis and the development of targeted therapies. Therefore, in this article, we review Kynurenine and how it plays a vital role in BMSC dysfunction and bone loss with age.

MicroRNAs are critical regulators of senescence and aging in mesenchymal stem cells.

MicroRNAs (miRNAs) have recently come under scrutiny for their role in various age-related diseases. Similarly, cellular senescence has been linked to disease and aging. MicroRNAs and senescence likely play an intertwined role in driving these pathologic states. In this review, we present the connection between these two drivers of age-related disease concerning mesenchymal stem cells (MSCs). First, we summarize key miRNAs that are differentially expressed in MSCs and other musculoskeletal lineage cells during senescence and aging. Additionally, we also reviewed miRNAs that are regulated via traditional senescence-associated secretory phenotype (SASP) cytokines in MSC. Lastly, we summarize miRNAs that have been found to target components of the cell cycle arrest pathways inherently activated in senescence. This review attempts to highlight potential miRNA targets for regenerative medicine applications in age-related musculoskeletal disease.

Abiotic stressors impact outer membrane vesicle composition in a beneficial rhizobacterium: Raman spectroscopy characterization.

Outer membrane vesicles (OMVs) produced by Gram-negative bacteria have roles in cell-to-cell signaling, biofilm formation, and stress responses. Here, the effects of abiotic stressors on OMV contents and composition from biofilm cells of the plant health-promoting bacterium Pseudomonas chlororaphis O6 (PcO6) are examined. Two stressors relevant to this root-colonizing bacterium were examined: CuO nanoparticles (NPs)-a potential fertilizer and fungicide- and H2O2-released from roots during plant stress responses. Atomic force microscopy revealed 40-300 nm diameter OMVs from control and stressed biofilm cells. Raman spectroscopy with linear discriminant analysis (LDA) was used to identify changes in chemical profiles of PcO6 cells and resultant OMVs according to the cellular stressor with 84.7% and 83.3% accuracies, respectively. All OMVs had higher relative concentrations of proteins, lipids, and nucleic acids than PcO6 cells. The nucleic acid concentration in OMVs exhibited a cellular stressor-dependent increase: CuO NP-induced OMVs > H2O2-induced OMVs > control OMVs. Biochemical assays confirmed the presence of lipopolysaccharides, nucleic acids, and protein in OMVs; however, these assays did not discriminate OMV composition according to the cellular stressor. These results demonstrate the sensitivity of Raman spectroscopy using LDA to characterize and distinguish cellular stress effects on OMVs composition and contents.

A Systematic Review on Outcomes of Anterior Skull Base Reconstruction.

INTRODUCTION: Anterior skull base resection often results in large defects that need to be reconstructed. This can be done using loco-regional, free flaps or both. OBJECTIVE: The aim of this systematic review is to evaluate the surgical outcomes (mortality, complication rates and functional outcomes) for patients undergoing anterior skull base reconstruction. METHODS: Electronic databases (MEDLINE, EMBASE and Scopus) were systematically searched for relevant articles from 1974 to March 2018. A total of 41 studies were included in this systematic review. No randomized controlled trials were identified; therefore, a meta-analysis was not performed. RESULTS: Mortality from anterior skull base reconstruction were about 0-4% for loco-regional flaps while free flaps were around 0-7%. Overall complications ranged from 0% to 43% in loco-regional flaps, while rate of complications for free flaps ranged from 25% to 66.7%. Flap complications ranged from 0% to 14% for free flaps and 0% to 35% for local flaps. Quality-of-life measures did not differ significantly depending on surgical approach but were worse for patients with malignancies. CONCLUSION: Due to varying standards of reporting of outcomes, lack of a standardized classification system for anterior skull base defects and absence of clinical trials, we were unable to perform a meta-analysis in this systematic review. Recommendations to guide future studies are proposed.

The Significance of Metal Coordination in Imidazole-Functionalized Metal-Organic Frameworks for Carbon Dioxide Utilization.

The grafting of imidazole species onto coordinatively unsaturated sites within metal-organic framework MIL-101(Cr) enables enhanced CO2 capture in close proximity to catalytic sites. The subsequent combination of CO2 and epoxide binding sites, as shown through theoretical findings, significantly improves the rate of cyclic carbonate formation, producing a highly active CO2 utilization catalyst. An array of spectroscopic investigations, in combination with theoretical calculations reveal the nature of the active sites and associated catalytic mechanism which validates the careful design of the hybrid MIL-101(Cr).

Designing Multi-Dopant Species in Microporous Architectures to Probe Reaction Pathways in Solid-Acid Catalysis.

The introduction of two distinct dopants in a microporous zeotype framework can lead to the formation of isolated, or complementary catalytically active sites. Careful selection of dopants and framework topology can facilitate enhancements in catalysts efficiency in a range of reaction pathways, leading to the use of sustainable precursors (bioethanol) for plastic production. In this work we describe our unique synthetic design procedure for creating a multi-dopant solid-acid catalyst (MgSiAPO-34), designed to improve and contrast with the performance of SiAPO-34 (mono-dopant analog), for the dehydration of ethanol to ethylene. We employ a range of characterization techniques to explore the influence of magnesium substitution, with specific attention to the acidity of the framework. Through a combined catalysis, kinetic analysis and computational fluid dynamics (CFD) study we explore the reaction pathway of the system, with emphasis on the improvements facilitated by the multi-dopant MgSiAPO-34 species. The experimental data supports the validation of the CFD results across a range of operating conditions; both of which supports our hypothesis that the presence of the multi-dopant solid acid centers enhances the catalytic performance. Furthermore, the development of a robust computational model, capable of exploring chemical catalytic flows within a reactor system, affords further avenues for enhancing reactor engineering and process optimisation, toward improved ethylene yields, under mild conditions.

Exploring the origins of crystallisation kinetics in hierarchical materials using in situ X-ray diffraction and pair distribution function analysis.

The discovery of novel catalytic materials is predicated on understanding contemporary synthetic processes. With this fundamental knowledge in place it becomes possible to modify the final material with subtle changes to the synthesis process. In this vein, hierarchical materials, formed by the addition of a mesoporogen within the hydrothermal synthesis, have attracted a significant amount of attention due to their catalytic benefits over analogous microporous species. In this work we monitor the hydrothermal synthesis in situ of a hierarchical and a microporous aluminophosphate, for the first time, combining total scattering and pairwise distribution function data. In doing so we observe the local formation of the species, and the longer range crystallisation processes concurrently.

Care After REsuscitation: Implementation of the United Kingdom's First Dedicated Multidisciplinary Follow-Up Program for Survivors of Out-of-Hospital Cardiac Arrest.

Survival rates after cardiac arrest (CA) are increasing, with more patients and their families living with the psychological consequences of surviving a sudden CA. The currently available neuropsychological assessment tools and therapies were not designed for CA, and may be inadequate. The Essex Cardiothoracic Centre set up the United Kingdom's first dedicated multidisciplinary "Care After REsuscitation" (CARE) service, offering CA survivors and their caregivers systematic psychological, cognitive, and specialized medical support for the first 6 months after CA. Twenty-one patients were recruited into the CARE pilot service evaluation. Patients' health at hospital discharge was poor; however, by 6 months all components (except general health) had improved significantly, and were close to that experienced by "healthy" individuals. Five (26%) required referral to a psychiatrist, with all 5 (26%) subsequently being diagnosed with moderate-to-severe depression, and 3 (16%) with comorbid post-traumatic stress disorder. Our study demonstrates a large unmet clinical need in general and neuropsychological assessment, and our results suggest that offering appropriate and prompt specialist diagnosis and therapies leads to an improvement in health at 6 months.