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The primary fatty acid of coconut oil is lauric acid, which is present at approximately 45–53 %. The metabolic and physiological properties of lauric acid account for many of the properties of coconut oil. Coconut oil is rapidly metabolized because it is easily absorbed and lauric acid is easily transported. Detailed studies have shown that the majority of ingested lauric acid is transported directly to the liver where it is directly converted to energy and other metabolites rather than being stored as fat. Such metabolites include ketone bodies, which can be used by extrahepatic tissues, such as the brain and heart, as an immediate form of energy. Studies on the effect of lauric acid on serum cholesterol are contradictory. Among saturated fatty acids, lauric acid has been shown to contribute the least to fat accumulation. Lauric acid and monolaurin have demonstrably significant antimicrobial activity against gram positive bacteria and a number of fungi and viruses. Today there are many commercial products that use lauric acid and monolaurin as antimicrobial agents. Because of the significant differences in the properties of lauric acid relative to longer chain fatty acids, they are typically differentiated as medium-chain fatty acids covering C6–C12, and long-chain fatty acids covering C14 and longer.

Purpose of ReviewGastric adenocarcinoma is the fifth most common and the third most lethal cancer worldwide. Surgery is the only chance of cure, but recurrence is common, even with complete resection.Recent FindingsAdvances in diagnosis and staging, genomic classification, surgical resection and treatment of peritoneal disease, systemic chemotherapy and chemoradiation, and targeted and immune therapies have led to the current multidisciplinary approach to gastric adenocarcinoma.SummaryTreatment of gastric cancer is rapidly evolving in an effort to combat this challenging disease.

The CDC recommends that healthcare settings provide influenza patients with facemasks as a means of reducing transmission to staff and other patients, and a recent report suggested that surgical masks can capture influenza virus in large droplet spray. However, there is minimal data on influenza virus aerosol shedding, the infectiousness of exhaled aerosols, and none on the impact of facemasks on viral aerosol shedding from patients with seasonal influenza. We collected samples of exhaled particles (one with and one without a facemask) in two size fractions (\"coarse\">5 µm, \"fine\"≤5 µm) from 37 volunteers within 5 days of seasonal influenza onset, measured viral copy number using quantitative RT-PCR, and tested the fine-particle fraction for culturable virus. Fine particles contained 8.8 (95% CI 4.1 to 19) fold more viral copies than did coarse particles. Surgical masks reduced viral copy numbers in the fine fraction by 2.8 fold (95% CI 1.5 to 5.2) and in the coarse fraction by 25 fold (95% CI 3.5 to 180). Overall, masks produced a 3.4 fold (95% CI 1.8 to 6.3) reduction in viral aerosol shedding. Correlations between nasopharyngeal swab and the aerosol fraction copy numbers were weak (r = 0.17, coarse; r = 0.29, fine fraction). Copy numbers in exhaled breath declined rapidly with day after onset of illness. Two subjects with the highest copy numbers gave culture positive fine particle samples. Surgical masks worn by patients reduce aerosols shedding of virus. The abundance of viral copies in fine particle aerosols and evidence for their infectiousness suggests an important role in seasonal influenza transmission. Monitoring exhaled virus aerosols will be important for validation of experimental transmission studies in humans.

Background In times of global climate change, the conversion and capturing of inorganic CO2 have gained increased attention because of its great potential as sustainable feedstock in the production of biofuels and biochemicals. CO2 is not only the substrate for the production of value-added chemicals in CO2-based bioprocesses, it can also be directly hydrated to formic acid, a so-called liquid organic hydrogen carrier (LOHC), by chemical and biological catalysts. Recently, a new group of enzymes were discovered in the two acetogenic bacteria Acetobacterium woodii and Thermoanaerobacter kivui which catalyze the direct hydrogenation of CO2 to formic acid with exceptional high rates, the hydrogen-dependent CO2 reductases (HDCRs). Since these enzymes are promising biocatalysts for the capturing of CO2 and the storage of molecular hydrogen in form of formic acid, we designed a whole-cell approach for T. kivui to take advantage of using whole cells from a thermophilic organism as H2/CO2 storage platform. Additionally, T. kivui cells were used as microbial cell factories for the production of formic acid from syngas. Results This study demonstrates the efficient whole-cell biocatalysis for the conversion of H2 + CO2 to formic acid in the presence of bicarbonate by T. kivui. Interestingly, the addition of KHCO3 not only stimulated formate formation dramatically but it also completely abolished unwanted side product formation (acetate) under these conditions and bicarbonate was shown to inhibit the membrane-bound ATP synthase. Cell suspensions reached specific formate production rates of 234 mmol g−1protein h−1 (152 mmol g−1CDW h−1), the highest rates ever reported in closed-batch conditions. The volumetric formate production rate was 270 mmol L−1 h−1 at 4 mg mL−1. Additionally, this study is the first demonstration that syngas can be converted exclusively to formate using an acetogenic bacterium and high titers up to 130 mM of formate were reached. Conclusions The thermophilic acetogenic bacterium T. kivui is an efficient biocatalyst which makes this organism a promising candidate for future biotechnological applications in hydrogen storage, CO2 capturing and syngas conversion to formate.

The term vitamin B6 is a designation for the vitamers pyridoxal, pyridoxamine, pyridoxine and the respective phosphate esters pyridoxal-5′-phosphate (PLP), pyridoxamine-5′-phosphate and pyridoxine-5′-phosphate. Animals and humans are unable to synthesise vitamin B6. These organisms have to take up vitamin B6 with their diet. Therefore, vitamin B6 is of commercial interest as a food additive and for applications in the pharmaceutical industry. As yet, two naturally occurring routes for de novo synthesis of PLP are known. Both routes have been genetically engineered to obtain bacteria overproducing vitamin B6. Still, major genetic engineering efforts using the existing pathways are required for developing fermentation processes that could outcompete the chemical synthesis of vitamin B6. Recent suppressor screens using mutants of the Gram-negative and Gram-positive model bacteria Escherichia coli and Bacillus subtilis, respectively, carrying mutations in the native pathways or heterologous genes uncovered novel routes for PLP biosynthesis. These pathways consist of promiscuous enzymes and enzymes that are already involved in vitamin B6 biosynthesis. Thus, E. coli and B. subtilis contain multiple promiscuous enzymes causing a so-called underground metabolism allowing the bacteria to bypass disrupted vitamin B6 biosynthetic pathways. The suppressor screens also show the genomic plasticity of the bacteria to suppress a genetic lesion. We discuss the potential of the serendipitous pathways to serve as a starting point for the development of bacteria overproducing vitamin B6.Key points• Known vitamin B6 routes have been genetically engineered.• Underground metabolism facilitates the emergence of novel vitamin B6 biosynthetic pathways.• These pathways may be suitable to engineer bacteria overproducing vitamin B6.

Background Replacing fossil fuels as energy carrier requires alternatives that combine sustainable production, high volumetric energy density, easy and fast refueling for mobile applications, and preferably low risk of hazard. Molecular hydrogen (H2) has been considered as promising alternative; however, practical application is struggling because of the low volumetric energy density and the explosion hazard when stored in large amounts. One way to overcome these limitations is the transient conversion of H2 into other chemicals with increased volumetric energy density and lower risk hazard, for example so-called liquid organic hydrogen carriers such as formic acid/formate that is obtained by hydrogenation of CO2. Many homogenous and heterogenous chemical catalysts have been described in the past years, however, often requiring high pressures and temperatures. Recently, the first biocatalyst for this reaction has been described opening the route to a biotechnological alternative for this conversion. Results The hydrogen-dependent CO2 reductase (HDCR) is a highly active biocatalyst for storing H2 in the form of formic acid/formate by reversibly catalyzing the hydrogenation of CO2. We report the identification, isolation, and characterization of the first thermostable HDCR operating at temperatures up to 70 °C. The enzyme was isolated from the thermophilic acetogenic bacterium Thermoanaerobacter kivui and displays exceptionally high activities in both reaction directions, substantially exceeding known chemical catalysts. CO2 hydrogenation is catalyzed at mild conditions with a turnover frequency of 9,556,000 h−1 (specific activity of 900 µmol formate min−1 mg−1) and the reverse reaction, H2 + CO2 release from formate, is catalyzed with a turnover frequency of 9,892,000 h−1 (930 µmol H2 min−1 mg−1). The HDCR of T. kivui consists of a [FeFe] hydrogenase subunit putatively coupled to a tungsten-dependent CO2 reductase/formate dehydrogenase subunit by an array of iron–sulfur clusters. Conclusions The discovery of the first thermostable HDCR provides a promising biological alternative for a chemically challenging reaction and might serve as model for the better understanding of catalysts able to efficiently reduce CO2. The catalytic activity for reversible CO2 hydrogenation of this enzyme is the highest activity known for bio- and chemical catalysts and requiring only ambient temperatures and pressures. The thermostability provides more flexibility regarding the process parameters for a biotechnological application.

Many studies have identified an inequitable distribution of exposure to PM2.5 (particulate matter less than 2.5 microns) by race. We investigated the association of PM2.5 and cardiovascular mortality considering both the decedents' race and neighborhood racial composition as potential modifiers. We obtained geocoded cardiovascular mortality records of all black and white decedents from urban block-groups in Massachusetts between 2001 and 2011 (n = 130,863). We examined the association between PM2.5 and cardiovascular mortality, and assessed effect modification by three types of racial modifiers: decedents' race, census block-group percent black and white, and two novel measures of racial segregation. The Racial Residential Segregation (RRS) quantifies the concentration of non-Hispanic blacks and whites in each block-group. The Index of Racial Dissimilarity measures dissimilarity in non-Hispanic black and white racial distribution between the smaller census block-group and larger tract. We found a 2.35%(95%CI: 0.92%;3.79%) increase in mortality for each 10μg/m3 increase in two-day average exposure to PM2.5. The effect was modified by the block-group racial composition, with higher risks in block-groups with the highest percentage of black residents (interaction p-value = 0.04), and in block-groups with the lowest RRS (i.e. higher black to white resident ratio, interaction p-value = 0.072). Racial dissimilarity did not modify the associations. Current levels of PM2.5 are associated with increased cardiovascular deaths in Massachusetts, with different risks between areas with different racial composition and segregation. This suggests that pollution reductions in neighborhoods with the highest percentage of non-Hispanic blacks would be most beneficial in reducing cardiovascular mortality and disparities.

BackgroundThe Normalized Difference Vegetation Index (NDVI) is a measure of greenness widely used in environmental health research. High spatial resolution NDVI has become increasingly available; however, the implications of its use in exposure assessment are not well understood.ObjectiveTo quantify the impact of NDVI spatial resolution on greenness exposure misclassification.MethodsGreenness exposure was assessed for 31,328 children in the Greater Boston Area in 2016 using NDVI from MODIS (250 m2), Landsat 8 (30 m2), Sentinel-2 (10 m2), and the National Agricultural Imagery Program (NAIP, 1 m2). We compared continuous and categorical greenness estimates for multiple buffer sizes under a reliability assessment framework. Exposure misclassification was evaluated using NAIP data as reference.ResultsGreenness estimates were greater for coarser resolution NDVI, but exposure distributions were similar. Continuous estimates showed poor agreement and high consistency, while agreement in categorical estimates ranged from poor to strong. Exposure misclassification was higher with greater differences in resolution, smaller buffers, and greater number of exposure quantiles. The proportion of participants changing greenness quantiles was higher for MODIS (11–60%), followed by Landsat 8 (6–44%), and Sentinel-2 (5–33%).SignificanceGreenness exposure assessment is sensitive to spatial resolution of NDVI, aggregation area, and number of exposure quantiles. Greenness exposure decisions should ponder relevant pathways for specific health outcomes and operational considerations.

BackgroundI review the natural history of the tuco-tuco Ctenomys magellanicus in Patagonia and Tierra del Fuego, southernmost geographic regions shared by Argentina and Chile. By natural history I mean both historical records and ecological features of this gregarious burrowing rodent.Methods and resultsI conducted a selective review of the natural history of C. magellanicus, as recorded in mainstream journals and proceedings, landmark monographs and books, and internet sources. I report results on: (a) Original description, (b) Diversity and distribution, (c) Life history, (d) Interactions with plants and herbivorous competitors, (e) Interactions with predators other than humans, (f) Interactions with humans, and (g) Abundance and conservation. I also enter the anthropology field, but I only touch the archeology field. Although this review is not on the systematics of C. magellanicus, I do provide an updated overview of the phylogenetics-based taxonomy of the genus where it belongs.DiscussionThere is a rather large body of literature on C. magellanicus, comprising the fields of anthropology, archeology, biogeography, biology, ecology, and systematics. These areas are broadly covered but thinly treated, offering interesting opportunities for further research. For instance, on adaptation, evolution, and environmental impact of the southernmost burrowing rodent in the world and its cultural impact on vanishing native peoples, especially the Selk’nam.