Achieving ultra-high platinum utilization via optimization of PEM fuel cell cathode catalyst layer microstructure

Inefficient usage of expensive platinum catalyst has plagued the design of PEM fuel cells and contributed to the limited production and use of fuel cell systems. Here, it is shown that hierarchical optimization can increase platinum utilization 30-fold over existing catalyst layer designs while maintaining power densities over 0.35 W/cm2. The cathode catalyst layer microstructure is optimized with respect to platinum utilization (measured as kilowatts of electricity produced per gram of platinum). A one-dimensional agglomerate model that accounts for liquid water saturation is used in this study. The cathode catalyst layer microstructure is optimized by manipulating the platinum loading (m Pt), platinum-to-carbon ratio (Pt|C), and catalyst layer void fraction View the MathML source(εVcl). The resulting catalyst layer microstructure features ultra-low platinum loadings of roughly 0.01 mg/cm2

Bunge’s Mathematical Structuralism Is Not a Fiction

In this paper, I explore Bunge’s fictionism in philosophy of mathematics. After an overview of Bunge’s views, in particular his mathematical structuralism, I argue that the comparison between mathematical objects and fictions ultimately fails. I then sketch a different ontology for mathematics, based on Thomasson’s metaphysical work. I conclude that mathematics deserves its own ontology, and that, in the end, much work remains to be done to clarify the various forms of dependence that are involved in mathematical knowledge, in particular its dependence on mental/brain states and material objects

Impact of different SARS-CoV-2 assays on laboratory turnaround time.

Introduction. Clinical microbiology laboratories have had to cope with an increase in the volume of tests due to the emergence of the SARS-CoV-2 virus. Short turnaround times (TATs) are important for case tracing and to help clinicians in patient management. In such a context, high-throughput systems are essential to process the bulk of the tests. Rapid tests are also required to ensure shorter TATs for urgent situations. In our laboratory, SARS-CoV-2 assays were initially implemented on our custom platform using a previously published method. The commercial cobas 6800 (Roche diagnostics) assay and the GeneXpert Xpress (Cepheid) SARS-CoV-2 assay were implemented on 24 March and 8 April 2020, respectively, as soon as available.Hypothesis/Gap Statement. Despite the abundant literature on SARS-CoV-2 assays, the articles focus mainly on the diagnostic performances. This is to our knowledge the first article that specifically studies the TAT of different assays.Aim. We aimed to describe the impact of various SARS-CoV-2 assays on the TAT at the beginning of the outbreak.Methodology. In this study, we retrospectively analysed the TAT of all SARS-CoV-2 assays performed in our centre between 24 February and 9 June, 2020.Results. We retrieved 33 900 analyses, with a median TAT of 6.25 h. TATs were highest (6.9 h) when only our custom platform was used (24 February to 24 March, 2020). They were reduced to 6.1 h when the cobas system was introduced (24 March to 8 April, 2020). The implementation of the GeneXpert further reduced the median TAT to 4.8 h (8 April to 9 June, 2020). The GeneXpert system had the shortest median TAT (1.9 h), followed by the cobas (5.5 h) and by our custom platform (6.9 h).Conclusion. This work shows that the combination of high-throughput systems and rapid tests allows the efficient processing of a large number of tests with a short TAT. In addition, the use of a custom platform allowed the quick implementation of an in-house test when commercial assays were not yet available

Microenterprise development coupled with nutrition education can help increase caregivers’ incomes and household accessibility to animal source foods

Low income and lack of knowledge about child nutrition have been identified as key constraints to the use of Animal Source Foods (ASF) in the diets of young Ghanaian children. To improve ASF consumption among children in Ghana, the Enhancing Child Nutrition through Animal Source Food Management (ENAM) project introduced an intervention that combined women’s microenterprise development activities with nutrition education on the importance of ASF in children’s diets. The present study assessed the effects of the intervention on the participants’ enterprise performance, their contribution to key household and child-related expenditures as well as their households’ purchases of ASF. Additionally, household ASF consumption was assessed in monetary terms (measured in Ghana cedis (GH¢):1GH¢ = US$ 0.92).A structured questionnaire was used to interview 80 caregivers who participated in the ENAM project activities in four intervention communities and 80 non-participant caregivers in four control communities. Information solicited included household characteristics, profits from microenterprises and contributions to household food and non-food expenditures. Significantly more participant caregivers expanded (P=0.004) and diversified (P=0.004) their enterprises and, as a result, tended to have higher average enterprise profits (GH¢19.3 ± 2.2 vs. GH¢12.2 ± 1.9; P=0.08) and significantly higher savings (GH¢62.9 ± 2.2 vs. GH¢26.3 ± 1.9; P<0.05) than non-participant caregivers. In addition, the intervention was associated with significantly higher percentage of monetary contributions by caregivers towards children’s health expenses (P<0.05), school expenses (P<0.01) as well as expenses on clothing and footwear (P<0.01). Caregivers’ mean percentage contribution to household food expenses also tended to be higher (P<0.1) for participants (50.8 ± 3.5%) then for non-participants (41.8 ± 4.1%). Participant households also tended to spend more money (P<0.10) and consumed significantly more amounts (in monetary value) of ASF (P<0.01) than non-participant households. Being a participant in the ENAM project’s microenterprise development and nutrition education activities was associated with higher enterprise profits, savings deposits, contributions to householdand children-related expenditures, and ASF consumption at the household level

Dietary intakes and iron status of vegetarian and non-vegetarian children in selected communities in Accra and cape coast, Ghana

There is a scarcity of information on dietary intake and iron status of Ghanaian children raised on vegetarian diets. A cross-sectional study design was used to compare the diets and iron status of vegetarian children between the ages of 9 months and 11 years (n= 26) with matched controls, non-vegetarian children (n=26) of similar ages and same sex and living within the same communities in Accra and Cape Coast, Ghana. Dietary information was collected using 24-hr food recall and 12-hr home observation. Haemoglobin, plasma ferritin, C-reactive protein, and Transferrin Receptor (TfR) concentrations were determined on finger prick (haemoglobin) and venous blood samples collected during the study. Based on the 24-hr food recall, vegetarian children’s diets were devoid of vitamin B12whereas non-vegetarian children’s diets were not (0.0 ± 0.0 mg vs. 1.5 ± 1.8 mg, p<0.001). The dietary intake based on 12-hr home observation showed similar results. However, vegetarians had significantly higher intake of dietary fibre (17.1 ± 11.9 g vs. 8.4 ± 6.2 g, p= 0.002), thiamine (1.1 ± 0.8 mg vs. 0.5 ± 0.3 mg, p= 0.001) and vitamin A (1702 ± 1887 Retinol Equivalent (RE)vs. 671 ± 691 RE, p= 0.010) than non-vegetarian children. Dietary diversity based on nine food groups was similar between groups (5.8 ±1.0score). Plasma ferritin was higher for non-vegetarian children compared to the vegetarians (59.2± 48.2 ng/mL vs. 34.1± 25.8ng/ml, p= 0.012) but there was no group difference in plasma TfR. The prevalence of anaemia was about 25% in both groups. Typical diets of Ghanaian children lack variety and both vegetarian and nonvegetarian diets are insufficient to support adequate iron status. Iron-rich foods such as meat or supplements are needed. There is urgent need for immediate vitamin B12 supplementation for all vegetarian children and a general need for nutrition education to diversify all children’s diets

In Vitro Analysis of Tobramycin-Treated Pseudomonas aeruginosa Biofilms on Cystic Fibrosis-Derived Airway Epithelial Cells

P. aeruginosa forms biofilms in the lungs of individuals with cystic fibrosis (CF); however, there have been no effective model systems for studying biofilm formation in the CF lung. We have developed a tissue culture system for growth of P. aeruginosa biofilms on CF-derived human airway cells that promotes the formation of highly antibiotic-resistant microcolonies, which produce an extracellular polysaccharide matrix and require the known abiotic biofilm formation genes flgK and pilB. Treatment of P. aeruginosa biofilms with tobramycin reduced the virulence of the biofilms both by reducing bacterial numbers and by altering virulence gene expression. We performed microarray analysis of these biofilms on epithelial cells after treatment with tobramycin, and we compared these results with gene expression of (i) tobramycin-treated planktonic P. aeruginosa and (ii) tobramycin-treated P. aeruginosa biofilms on an abiotic surface. Despite the conservation in functions required to form a biofilm, our results show that the responses to tobramycin treatment of biofilms grown on biotic versus abiotic surfaces are different, as exemplified by downregulation of genes involved in Pseudomonas quinolone signal biosynthesis specifically in epithelial cell-grown biofilms versus plastic-grown biofilms. We also identified the gene PA0913, which is upregulated by tobramycin specifically in biofilms grown on CF airway cells and codes for a probable magnesium transporter, MgtE. Mutation of the PA0913 gene increased the bacterial virulence of biofilms on the epithelial cells, consistent with a role for the gene in the suppression of bacterial virulence. Taken together, our data show that analysis of biofilms on airway cells provides new insights into the interaction of these microbial communities with the host

Enhancing backyard poultry enterprise performance in the techiman area: A value chain analysis

Backyard Poultry (BP) production is widespread among rural households in Ghana and provides an opportunity for small scale enterprise development to contribute to poverty alleviation. Traditionally, efforts to improve poultry production activities have emphasized the technical aspects of production while neglecting the social and organizational processes that underlie BP enterprises. A value chain framework was used to qualitatively assess BP enterprises in two communities in the Techiman Municipality of the Brong Ahafo Region in Ghana. The main purpose of the study was to understand how the activities and relationships among actors along the BP value chain influence BP enterprise performance and its implications for development of the industry. Community key informants defined a BP enterprise as ownership of at least ten post vulnerability age chickens (defined as ability to roost on trees to escape predators and disease). All identified BP farmers in the communities were classified as ‘high’ and ‘low’ enterprise performers based on flock size of ‘post- vulnerability age chickens’. The study participants included a purposive sample of ‘low’ (n=10) and ‘high’ (n=10) performing BP farmers from each community as well as service providers and support institutions in the BP value chain identified through snowball sampling. Qualitative data were collected using focus group discussions and key informant interviews. Content analysis was used to summarize themes and patterns from the interview transcripts and to compare high and low performing BP enterprises based on the identified activities and relationships. Higher BP enterprise performance was associated with stronger inter- and intra-actor integration of activities in the various functions of the value chain and higher investment of resources in the activities of the value chain. Additionally, opportunities for import substitution to meet the high national demand for chicken meat were identified. Sustainable improvements in the BP sector must involve social, relational, organizational, as well as technical innovation

Relationship between caregivers’ income generation activities and their children’s animal source food intake

Enhancing Child Nutrition through Animal Source Food Management (ENAM) project provided financial and technical support for caregivers’ Income Generation Activities (IGA) with the aim of increasing their access to Animal Source Foods (ASF) for improved child nutrition. Using baseline data from the ENAM project, this study assessed the relationship between the type of caregivers’ IGA -whether it is related to ASF [ASF-R] or unrelated [ASF-U] - and the quantity and diversity of ASF consumed by their children. Structured questionnaire was used to obtain data on household socioeconomic and demographic characteristics and children’s ASF consumption in the past week from 530 caregivers of children 2-to5 years old in 12 communities in three agro-ecological zones of Ghana. A weighed food record of children’s dietary intakes was also completed during two 12-hour home observations on a randomly selected sample of 117 children. Approximately 6% (n=32) of caregivers were not engaged in any IGA. Of the caregivers who were involved in an IGA (n=498), approximately one-third of them were engaged in an ASF-R IGA, such as selling smoked fish, selling eggs and the selling cooked food that included ASF. Caregivers (67%) were engaged in ASF-U IGA, such as crop farming, petty trading in non ASF items and artisanal work. The quantity and diversity of ASF consumed by the children did not differ (p=0.988 and p=0.593, respectively) by the type of caregiver IGA. However, after accounting for agro-ecological zone, being involved in an ASF-R IGA positively predicted children’s ASF diversity (p<0.001). The number of children in the household negatively predicted children’s ASF diversity (p=0.011) whereas high/medium household wealth status tended to be positively associated with ASF diversity (p=0.064).The study suggested that there is need to promote ASF-R IGA among caregivers to increase the ability to purchase more varied and nutritious food items for improving children’s growth