Water droplet accumulation and motion in PEM (Proton Exchange Membrane) fuel cell mini-channels

Effective water management is one of the key strategies for improving low temperature Proton Exchange Membrane (PEM) fuel cell performance and durability. Phenomena such as membrane dehydration, catalyst layer flooding, mass transport and fluid flow regimes can be affected by the interaction, distribution and movement of water in flow plate channels. In this paper a literature review is completed in relation to PEM fuel cell water flooding. It is clear that droplet formation, movement and interaction with the Gas Diffusion Layer (GDL) have been studied extensively. However slug formation and droplet accumulation in the flow channels has not been analysed in detail. In this study, a Computational Fluid Dynamic (CFD) model and Volume of Fluid (VOF) method is used to simulate water droplet movement and slug formation in PEM fuel cell mini-channels. In addition, water slug visualisation is recorded in ex situ PEM fuel cell mini-channels. Observation and simulation results are discussed with relation to slug formation and the implications to PEM fuel cell performance

Partial pulmonary embolization disrupts alveolarization in fetal sheep

BACKGROUND: Although bronchopulmonary dysplasia is closely associated with an arrest of alveolar development and pulmonary capillary dysplasia, it is unknown whether these two features are causally related. To investigate the relationship between pulmonary capillaries and alveolar formation, we partially embolized the pulmonary capillary bed. METHODS: Partial pulmonary embolization (PPE) was induced in chronically catheterized fetal sheep by injection of microspheres into the left pulmonary artery for 1 day (1d PPE; 115d gestational age; GA) or 5 days (5d PPE; 110-115d GA). Control fetuses received vehicle injections. Lung morphology, secondary septal crests, elastin, collagen, myofibroblast, PECAM1 and HIF1 alpha abundance and localization were determined histologically. VEGF-A, Flk-1, PDGF-A and PDGF-R alpha mRNA levels were measured using real-time PCR. RESULTS: At 130d GA (term approximately 147d), in embolized regions of the lung the percentage of lung occupied by tissue was increased from 29 +/- 1% in controls to 35 +/- 1% in 1d PPE and 44 +/- 1% in 5d PPE fetuses (p < 0.001). Secondary septal crest density was reduced from 8 +/- 0% in controls to 5 +/- 0% in 1d PPE and 4 +/- 0% in 5d PPE fetuses (p < 0.05), indicating impaired alveolar formation. The deposition of differentiated myofibroblasts (23 +/- 1% vs 28 +/- 1%; p < 0.001) and elastin fibres (3 +/- 0% vs 4 +/- 0%; p < 0.05) were also impaired in embolized lung regions of PPE fetuses compared to controls. PPE did not alter the deposition of collagen or PECAM1. At 116d GA in 5d PPE fetuses, markers of hypoxia indicated that a small and transient hypoxic event had occurred (hypoxia in 6.7 +/- 1.4% of the tissue within embolized regions of 5d PPE fetuses at 116d compared to 0.8 +/- 0.2% of tissue in control regions). There was no change in the proportion of tissue labelled with HIF1 alpha. There was no change in mRNA levels of the angiogenic factors VEGF and Flk-1, although a small increase in PDGF-R alpha expression at 116d GA, from 1.00 +/- 0.12 in control fetuses to 1.61 +/- 0.18 in 5d PPE fetuses may account for impaired differentiation of alveolar myofibroblasts and alveolar development. CONCLUSIONS: PPE impairs alveolarization without adverse systemic effects and is a novel model for investigating the role of pulmonary capillaries and alveolar myofibroblasts in alveolar formation

Transforming food systems in Maritime Southeast Asia and Pacific Small Island Developing States to support food security and sustainable healthy diets

Food is one of the basic necessities for human life. Nutritious food is essential for human health and helps oneself live up to our best potential as productive members of society. In spite of this, 3 billion people are estimated to have limited access to nutrient-rich food, and there are 768 million undernourished people in the globe today. There are still concerns with food systems and food security, despite the fast economic transformation of low-and middle-income nations in Maritime Southeast Asia and Oceania over the past 10 years. These issues include dwindling agricultural land, deforestation, ineffective food supply networks, environmental degradation, changing and unhealthy diets, non-communicable diseases, disappearing cultural legacy, and ineffective policies. These problems are exacerbated by climate change, natural hazards, and pandemic shocks. This review explores the perspectives of food systems that relates to all the elements and activities in transforming agri-food industry. In this paper, we discuss the challenges and solutions to transforming food systems in this region to achieve a sustainable and healthy diet for all, with the perspective of bringing the region closer toward the UN sustainable development goals. This paper is an outcome of the deliberations that took place during the Food Security in Small Islands and Developing States workshop in 2020. It also includes insights from subsequent expert group sessions that focused on the following topics: Agriculture and Food Systems; Nutrition, Health, and Culture; Innovations and Digitalization in Food Systems; as well as Policies Coordination and Future Shocks

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND: The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting. METHODS: Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups. RESULTS: Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005). CONCLUSION: Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery

MALARIA IN THE MALAYSIAN ARMY WITH PARTICULAR REFERENCE TO CHEMOSUPPRESSIVE USE

Malaria is the most important communicable disease in the field for the Malaysian soldier. His chief weapon is chemoprophylaxis. This was proguanil hydrochloride in the &apos;50s, changed to Darae/or in 1962; since late 1985, Fansidar only is used. The incidence of malaria over the years has fluctuated widely and had its peak in 1977 at 29.7/1,000 soldiers and since then has shown a downward trend. Studies carried out to study the problem are noted briefly. Antimalarial discipline in the field, continued surveillance and integrated control measlfres in the base are emphasised in the figh t against malaria

A dichotomous PCR–RFLP identification key for the freshwater mussels (Bivalvia: Unionida) of Peninsular Malaysia

Accurate species identification is the basis for successful species conservation and research, but extensive phenotypic plasticity in freshwater mussel (Bivalvia: Unionida) species often leads to misidentification by morphology alone. Molecular techniques have proven a powerful alternative tool for identification of freshwater mussels in North America and Europe. Unfortunately, no such tools are currently available for tropical mussels, which are subject to particularly severe habitat alteration and destruction. We developed a PCR–RFLP key for the freshwater mussel fauna of Peninsular Malaysia, comprising nine native and one non-native species from seven genera and three unionid subfamilies (Gonideinae, Rectidentinae and Anodontinae). The key enables identification of each species in two to four single digestion steps using six restriction endonucleases. All species can be identified using a single PCR fragment of 374 bp length (Histone H3) with the exception of two Pseudodon species, which can be differentiated through amplification and subsequent digestion of a 709 bp CO1 gene fragment. Reliability of the key was tested with specimens from 46 populations sampled from 13 different river basins of Peninsular Malaysia

Measuring encapsulation efficiency in cell-mimicking giant unilamellar vesicles

One of the main drivers within the field of bottom-up synthetic biology is to develop artificial chemical machines, perhaps even living systems, that have programmable functionality. Numerous toolkits exist to generate giant unilamellar vesicle-based artificial cells. However, methods able to quantitatively measure their molecular constituents upon formation is an underdeveloped area. We report an artificial cell quality control (AC/QC) protocol using a microfluidic-based single-molecule approach, enabling the absolute quantification of encapsulated biomolecules. While the measured average encapsulation efficiency was 11.4 ± 6.8%, the AC/QC method allowed us to determine encapsulation efficiencies per vesicle, which varied significantly from 2.4 to 41%. We show that it is possible to achieve a desired concentration of biomolecule within each vesicle by commensurate compensation of its concentration in the seed emulsion. However, the variability in encapsulation efficiency suggests caution is necessary when using such vesicles as simplified biological models or standards

Toll-Like Receptor 3 Expression in Glia and Neurons Alters in Response to White Matter Injury in Preterm Infants

Toll-like receptors (TLRs) are members of the pattern recognition receptor family that detect components of foreign pathogens or endogenous molecules released in response to injury. Recent studies demonstrate that TLRs also have a functional role in regulating neuronal proliferation in the developing brain. This study investigated cellular expression of TLR3 using immunohistochemistry on human brain tissue. The tissue sections analysed contained anterior and lateral periventricular white matter from the frontal and parietal lobes in post-mortem neonatal cases with a postmenstrual age range of 23.6-31.4 weeks. In addition to preterm brains without overt pathology (control), preterm pathology cases with evidence of white matter injuries (WMI) were also examined. In order to identify TLR-positive cells, we utilized standard double-labelling immunofluorescence co-labelling techniques and confocal microscopy to compare co-expression of TLR3 with a neuronal marker (NeuN) or with glial markers (GFAP for astrocytes, Iba-1 for microglia and Olig2 for oligodendrocytes). We observed an increase in the neuronal (28 vs. 17%) and astroglial (38 vs. 21%) populations in the WMI group compared to controls in the anterior regions of the periventricular white matter in the frontal lobe. The increase in neurons and astrocytes in the WMI cases was associated with an increase in TLR3 immunoreactivity. This expression was significantly increased in the astroglia. The morphology of the TLR3 signal in the control cases was globular and restricted to the perinuclear region of the neurons and astrocytes, whilst in the cases of WMI, both neuronal, axonal and astroglial TLR3 expression was more diffuse (i.e., a different intracellular distribution) and could be detected along the extensions of the processes. This study demonstrates for the first time that neurons and glial cells in human neonatal periventricular white matter express TLR3 during development. The patterns of TLR3 expression were altered in the presence of WMI, which might influence normal developmental processes within the immature brain. Identifying changes in TLR3 expression during fetal development may be key to understanding the reduced volumes of grey matter and impaired cortical development seen in preterm infants