270 research outputs found

    Integrative DNA Methylation and Gene Expression Analyses Identify DNA Packaging and Epigenetic Regulatory Genes Associated with Low Motility Sperm

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    In previous studies using candidate gene approaches, low sperm count (oligospermia) has been associated with altered sperm mRNA content and DNA methylation in both imprinted and non-imprinted genes. We performed a genome-wide analysis of sperm DNA methylation and mRNA content to test for associations with sperm function. (NCBI 1788). There was a trend among altered expression of these epigenetic regulatory genes and RPMM DNA methylation class.Using integrative genome-wide approaches we identified CpG methylation profiles and mRNA alterations associated with low sperm motility

    Nanoscale atoms in solid-state chemistry

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    Reports Conventional binary solid-state compounds, A x B y , are infinite, crystalline arrays of atoms A and B. Here we describe analogous binary solids in which the "atomic" building blocks are pseudo-spherical molecular clusters rather than simply atoms [for reviews on molecular clusters, see (1-3)]. We prepare these new solids by simply combining independently synthesized molecular clusters (4-6). The internal structures of the constituent clusters remain unchanged, but charge is transferred between them, forming ionic solids analogous to NaCl. We report three new solids: [ [C 60 ]. The former two assemble into a superatomic relative of the CdI 2 structure type, and the latter forms a simple rock-salt crystal. Despite their ready availability, molecular clusters have been used infrequently as electronic materials. Noteworthy examples of success in this area are the organic-inorganic hybrid materials reported by Batail and Mitzi (7-11). Nanocrystals have been assembled into striking superlattices (12-14), but they do not have discrete structural, electronic and magnetic properties and cannot be regarded as genuine artificial atoms. Here, we combine independently prepared electronically and structurally complementary molecular cluster building blocks to form atomically precise binary solid-state compounds. When the building blocks are atoms (ions), binary solids assemble into simple crystalline arrays such as the rock-salt and CdI 2 lattices [for an authoritative text on solid-state inorganic chemistry, see (15)]. We show that when similarlysized clusters combine the same lattice results, albeit at the dramatically increased length scale of nanometers rather than Angstroms. The constituent clusters interact to produce collective properties such as electrically conducting networks and magnetic ordering. Our strategy was to use constituent molecular clusters that have the same, roughly spherical, shape but very different electronic properties in order to encourage reaction and subsequent structural association. By analogy to "atomic" solid-state chemistry, we reasoned that the in situ transfer of charge would produce ions (or the equivalent) that could then form an ordered solid. Thus, we sought cluster pairs in which one cluster is relatively electron-poor and the other is relatively electron-rich. C 60 carbon clusters are good electron acceptors (16). The electrically neutral metal chalcogenide clusters Co 6 Se 8 (PEt 3 ) We combined 1 and two equivalents of C 60 in toluene and obtained black crystals after ~12 hours. Single-crystal x-ray diffraction (SCXRD) revealed that this solid is a 1:2 stoichiometric combination of 1 and C 60 (1β€’2C 60 ) Nanoscale Atoms in Solid-State Chemistry We measured how much charge was transferred between the components in the solid-state material using Raman spectroscopy. The A 2 g pentagonal pinch mode of C 60 (1468 cm -1 for pristine C 60 ) shifts to lower energy by 6 cm -1 per electron transferred to C 60 independent of the dopant or the crystal structure [see, for example, (19); for a review on discrete fulleride anions, see β€’βˆ’ (20). Cluster 1 has four weak transitions between 350 and 700 nm that were observed in 1β€’2C 60 but not in 2β€’2C 60 . We can compare these solids to traditional simple M 2+ X 1-2 solids. The CdI 2 structure type (21) is formed by a hexagonally close-packed array of monoanions with half of the octahedral interstitial sites occupied by dications. The cations are ordered such that along the crystallographic c-direction the cation layers are alternatively empty and fully occupied, and the layers are held together by van der Waals bonding between anions of neighboring layers. The structures of compounds 1β€’2C 60 and 2β€’2C 60 can be appreciated in these same terms. Wireframe representation of 1β€’2C 60 are shown i

    Localising the auditory N1m with event-related beamformers:localisation accuracy following bilateral and unilateral stimulation

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    The auditory evoked N1m-P2m response complex presents a challenging case for MEG source-modelling, because symmetrical, phase-locked activity occurs in the hemispheres both contralateral and ipsilateral to stimulation. Beamformer methods, in particular, can be susceptible to localisation bias and spurious sources under these conditions. This study explored the accuracy and efficiency of event-related beamformer source models for auditory MEG data under typical experimental conditions: monaural and diotic stimulation; and whole-head beamformer analysis compared to a half-head analysis using only sensors from the hemisphere contralateral to stimulation. Event-related beamformer localisations were also compared with more traditional single-dipole models. At the group level, the event-related beamformer performed equally well as the single-dipole models in terms of accuracy for both the N1m and the P2m, and in terms of efficiency (number of successful source models) for the N1m. The results yielded by the half-head analysis did not differ significantly from those produced by the traditional whole-head analysis. Any localisation bias caused by the presence of correlated sources is minimal in the context of the inter-individual variability in source localisations. In conclusion, event-related beamformers provide a useful alternative to equivalent-current dipole models in localisation of auditory evoked responses

    Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. 1. Estimating the Burden of Disease Associated with Pathogens

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    The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2–9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28 600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series

    Permanent Campaigning: A Meta-Analysis and Framework for Measurement

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    Permanent campaigning emerged as a concept in the 1970s in studies of US politics but is now recognized as a universal phenomenon. Despite its long history, there has been no attempt to build a holistic picture of the elements that constitute a permanent campaign. Generally, researchers focus on tactical elements, situating their use within an overall strategy, but there is a lack of a broader methodological framework for holistically measuring adherence to the permanent campaigning. This article presents results of a meta-analysis of relevant research to provide a framework to understand how permanent campaigning is practiced. Our study showed there were three reasonably discrete forms of campaigning activities that had been identified: those in which permanent campaign strategies are related to capacity building and strategy; a second, in which permanent campaigning relates to paid and owned media; and a third in which earned media is the main focus. In mapping these studies, we identify the common features of permanent campaigning, identifying strong and weak indicators and the extent these are employed by the government, parties, or elected representatives and within which political systems: parliamentarism or presidentialism. Our framework can be applied in future comparative research to understand trends in political communication

    Molecular Mining of Alleles in Water Buffalo Bubalus bubalis and Characterization of the TSPY1 and COL6A1 Genes

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    discovered in the process. gene in water buffalo, which localized to the Y chromosome.The MASA approach enabled us to identify several genes, including two of clinical significance, without screening an entire cDNA library. Genes identified with TGG repeats are not part of a specific family of proteins and instead are distributed randomly throughout the genome. Genes showing elevated expression in the testes and spermatozoa may prove to be potential candidates for in-depth characterization. Furthermore, their possible involvement in fertility or lack thereof would augment animal biotechnology

    Developmental exposures to common environmental contaminants, DEHP and lead, alter adult brain and blood hydroxymethylation in mice

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    Introduction: The developing epigenome changes rapidly, potentially making it more sensitive to toxicant exposures. DNA modifications, including methylation and hydroxymethylation, are important parts of the epigenome that may be affected by environmental exposures. However, most studies do not differentiate between these two DNA modifications, possibly masking significant effects.Methods: To investigate the relationship between DNA hydroxymethylation and developmental exposure to common contaminants, a collaborative, NIEHS-sponsored consortium, TaRGET II, initiated longitudinal mouse studies of developmental exposure to human-relevant levels of the phthalate plasticizer di(2-ethylhexyl) phthalate (DEHP), and the metal lead (Pb). Exposures to 25Β mg DEHP/kg of food (approximately 5Β mg DEHP/kg body weight) or 32Β ppm Pb-acetate in drinking water were administered to nulliparous adult female mice. Exposure began 2Β weeks before breeding and continued throughout pregnancy and lactation, until offspring were 21 days old. At 5Β months, perinatally exposed offspring blood and cortex tissue were collected, for a total of 25 male mice and 17 female mice (n = 5–7 per tissue and exposure). DNA was extracted and hydroxymethylation was measured using hydroxymethylated DNA immunoprecipitation sequencing (hMeDIP-seq). Differential peak and pathway analysis was conducted comparing across exposure groups, tissue types, and animal sex, using an FDR cutoff of 0.15.Results: DEHP-exposed females had two genomic regions with lower hydroxymethylation in blood and no differences in cortex hydroxymethylation. For DEHP-exposed males, ten regions in blood (six higher and four lower) and 246 regions (242 higher and four lower) and four pathways in cortex were identified. Pb-exposed females had no statistically significant differences in blood or cortex hydroxymethylation compared to controls. Pb-exposed males, however, had 385 regions (all higher) and six pathways altered in cortex, but no differential hydroxymethylation was identified in blood.Discussion: Overall, perinatal exposure to human-relevant levels of two common toxicants showed differences in adult DNA hydroxymethylation that was specific to sex, exposure type, and tissue, but male cortex was most susceptible to hydroxymethylation differences by exposure. Future assessments should focus on understanding if these findings indicate potential biomarkers of exposure or are related to functional long-term health effects

    Absence of Colony Stimulation Factor-1 Receptor Results in Loss of Microglia, Disrupted Brain Development and Olfactory Deficits

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    The brain contains numerous mononuclear phagocytes called microglia. These cells express the transmembrane tyrosine kinase receptor for the macrophage growth factor colony stimulating factor-1 (CSF-1R). Using a CSF-1R-GFP reporter mouse strain combined with lineage defining antibody staining we show in the postnatal mouse brain that CSF-1R is expressed only in microglia and not neurons, astrocytes or glial cells. To study CSF-1R function we used mice homozygous for a null mutation in the Csflr gene. In these mice microglia are >99% depleted at embryonic day 16 and day 1 post-partum brain. At three weeks of age this microglial depletion continues in most regions of the brain although some contain clusters of rounded microglia. Despite the loss of microglia, embryonic brain development appears normal but during the post-natal period the brain architecture becomes perturbed with enlarged ventricles and regionally compressed parenchyma, phenotypes most prominent in the olfactory bulb and cortex. In the cortex there is increased neuronal density, elevated numbers of astrocytes but reduced numbers of oligodendrocytes. Csf1r nulls rarely survive to adulthood and therefore to study the role of CSF-1R in olfaction we used the viable null mutants in the Csf1 (Csf1op) gene that encodes one of the two known CSF-1R ligands. Food-finding experiments indicate that olfactory capacity is significantly impaired in the absence of CSF-1. CSF-1R is therefore required for the development of microglia, for a fully functional olfactory system and the maintenance of normal brain structure
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