Compression of klockmannite, CuSe

Copper selenide (CuSe) was compressed in a diamond anvil cell at room temperature up to a pressure of 52 GPa and studied using energy dispersive x-ray diffraction and Raman spectroscopy. CuSe is nearly isostructural with copper sulfide (CuS), and a previous study indicates that copper sulfide undergoes reversible pressure-induced amorphization at 18 GPa. The intensity of the x-ray diffraction peaks for CuSe decrease slowly, however, they never completely disappear up to a pressure of 52 GPa. The third-order Birch–Murnaghan equation of state fit to the data yields K0 = 96.9±5.3 GPaK0=96.9±5.3GPa and K0′ = 4.1±0.5.K0′=4.1±0.5. Vinet’s universal equation of state yields essentially identical parameters. Raman spectroscopy demonstrates that upon compression, the S–S bond in CuS compresses differently than the Se–Se bond in CuSe, possibly accounting for the different high pressure behavior of these two very similar compounds. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70875/2/JCPSA6-109-2-634-1.pd

Examination of Edge Effects with Different Storage Conditions of Preplated Dimethyl Sulfoxide Nanospots in ChemLib 1,536- and 3,456-Well Assay-Ready Plates

For ultra-high-throughput screening, 10–30 nl of compound dissolved in 75% dimethyl sulfoxide (DMSO)/25% water (vol/vol) is spotted into 1,536- and 3,456-well ChemLib™ plates (Aurora Biotechnologies, Carlsbad, CA) and stored appropriately for a short time before screening. Although this practice eliminates the compound plating bottleneck, plated volumes of DMSO slowly evaporate from assay wells if plates are not properly stored in the interim. Since many assays are sensitive to DMSO concentrations, even slight evaporation may cause intra-plate variation and thus decrease assay quality. Using a cytochrome P450 3A4 Vivid® Blue assay (Invitrogen, Carlsbad), we investigated the rate, pattern, and quantity of evaporation over a 1-year time frame to identify best practices for long-term (i.e., 6 months or greater) storage of assay-ready compound plates. Our findings regarding evaporation at plate edges indicate that nanospots preplated in ChemLib 1,536- or 3,456-well plates are best stored at −80°C, in a bag, with or without the outer evaporation wells filled or at −20°C, in a bag, with evaporation wells filled.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63203/1/adt.2008.169.pd

Molecular Investigations of a Locally Acquired Case of Melioidosis in Southern AZ, USA

Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus, primarily found in soils in Southeast Asia and northern Australia. A recent case of melioidosis in non-endemic Arizona was determined to be the result of locally acquired infection, as the patient had no travel history to endemic regions and no previous history of disease. Diagnosis of the case was confirmed through multiple microbiologic and molecular techniques. To enhance the epidemiological analysis, we conducted several molecular genotyping procedures, including multi-locus sequence typing, SNP-profiling, and whole genome sequence typing. Each technique has different molecular epidemiologic advantages, all of which provided evidence that the infecting strain was most similar to those found in Southeast Asia, possibly originating in, or around, Malaysia. Advancements in new typing technologies provide genotyping resolution not previously available to public health investigators, allowing for more accurate source identification

Population genomics reveals that within-fungus polymorphism is common and maintained in populations of the mycorrhizal fungus Rhizophagus irregularis.

Arbuscular mycorrhizal (AM) fungi are symbionts of most plants, increasing plant growth and diversity. The model AM fungus Rhizophagus irregularis (isolate DAOM 197198) exhibits low within-fungus polymorphism. In contrast, another study reported high within-fungus variability. Experiments with other R. irregularis isolates suggest that within-fungus genetic variation can affect the fungal phenotype and plant growth, highlighting the biological importance of such variation. We investigated whether there is evidence of differing levels of within-fungus polymorphism in an R. irregularis population. We genotyped 20 isolates using restriction site-associated DNA sequencing and developed novel approaches for characterizing polymorphism among haploid nuclei. All isolates exhibited higher within-isolate poly-allelic single-nucleotide polymorphism (SNP) densities than DAOM 197198 in repeated and non-repeated sites mapped to the reference genome. Poly-allelic SNPs were independently confirmed. Allele frequencies within isolates deviated from diploids or tetraploids, or that expected for a strict dikaryote. Phylogeny based on poly-allelic sites was robust and mirrored the standard phylogeny. This indicates that within-fungus genetic variation is maintained in AM fungal populations. Our results predict a heterokaryotic state in the population, considerable differences in copy number variation among isolates and divergence among the copies, or aneuploidy in some isolates. The variation may be a combination of all of these hypotheses. Within-isolate genetic variation in R. irregularis leads to large differences in plant growth. Therefore, characterizing genomic variation within AM fungal populations is of major ecological importance

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Physiological Correlates of Volunteering

We review research on physiological correlates of volunteering, a neglected but promising research field. Some of these correlates seem to be causal factors influencing volunteering. Volunteers tend to have better physical health, both self-reported and expert-assessed, better mental health, and perform better on cognitive tasks. Research thus far has rarely examined neurological, neurochemical, hormonal, and genetic correlates of volunteering to any significant extent, especially controlling for other factors as potential confounds. Evolutionary theory and behavioral genetic research suggest the importance of such physiological factors in humans. Basically, many aspects of social relationships and social activities have effects on health (e.g., Newman and Roberts 2013; Uchino 2004), as the widely used biopsychosocial (BPS) model suggests (Institute of Medicine 2001). Studies of formal volunteering (FV), charitable giving, and altruistic behavior suggest that physiological characteristics are related to volunteering, including specific genes (such as oxytocin receptor [OXTR] genes, Arginine vasopressin receptor [AVPR] genes, dopamine D4 receptor [DRD4] genes, and 5-HTTLPR). We recommend that future research on physiological factors be extended to non-Western populations, focusing specifically on volunteering, and differentiating between different forms and types of volunteering and civic participation

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p