Optimization of Fabrication Technique to Prepare Acacia Wood Reinforced Bio-Composites

This chapter discuss the preparation and optimization of wood polymer composites based on the impregnation by polymer and nanoclay. Wood impregnation is one of the basic and most frequently used techniques to enhance the wood properties. This fabrication technique offers a wide range of applications depending on type of impregnants applied. Impregnation could make the wood less flammable, more dimensionally stable, more resistant to decay, harder, stronger, and more stable against UV rays. Softwood (Acacia) was impregnated with acrylonitrile, poly(vinyl) alcohol and organically nanoclay. The specimen preparation was carried out using the vacuum-chamber in a laboratory scale. The physical and mechanical properties of the modified wood were analyzed through Tensile and Flexural tests, SEM, FTIR, TGA and DSC. Mechanical test results shown that Tensile and Flexural strength have improvements with the addition of the nanofillers. The FTIR test shown that the chemical bonding between PVA into the wood cell would certainly enhance the matrix adhesion and contribute to its property enhancement. SEM illustrate the samples surface morphology which confirm the impregnation of the specimen. TGA results shown the additives impregnate into the wood component increase the thermal stability compared to the raw wood. DSC results indicate the impregnate wood has a higher melting temperature compared to the raw wood, due to existing of the polymer and nanoclay interfacial bonding among cell wall of the wood. Response surface methodology (RSM) was used to optimize the conditions for the preparation of wood composites. The design experiment was carried out using Design Expert 11

Mothers Frequent Caves: Lactation Affects Chimpanzee (Pan troglodytes verus) Cave Use in Southeastern Senegal

Caves play an important ecological role for nonhuman primates in Africa and Asia. Savanna chimpanzees (Pan troglodytes verus) living in the Mandingue plateau of Senegal and Mali use caves for thermoregulation, where these refugia provide a cool microclimate during the hot, dry season. In this study, we examined cave use frequency for a chimpanzee community in southeastern Senegal. We used images from a camera trap placed at the mouth of a large laterite cave to investigate the hypotheses that sex, reproductive state, and seasonality influence the frequency of cave use. The camera collected 14,053 still images of chimpanzees between 2011 and 2013 over 325 camera trap days. Our results indicate no difference in cave use frequency between males and females overall. However, female reproductive state did significantly influence cave use, with lactating mothers using the cave more frequently than both males and nonlactating females. Chimpanzees used the cave during the hottest times of the day and were more likely to visit the cave during periods of low water availability and high maximum temperatures associated with the dry season. These results suggest the importance of thermoregulation in extreme heat for all individuals, and specifically for lactating females with nursing infants that likely experience higher metabolic and hydration stress. This study provides insight into the dynamics of primate cave use by contributing evidence that chimpanzee cave use may be influenced by reproductive states in addition to thermoregulatory needs

Mapping the human genetic architecture of COVID-19

The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3,4,5,6,7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease