154 research outputs found
Environmental Factors Among Young Children Contributing to the Onset of Behavior Disorders
The purpose of this study was to look at the environmental factors young children have that affect how they are later in life, particularly the onset of behavior disorders. Negative environments and struggles in life can drastically affect how children act and the choices they make. Most problems I found in the research include low socioeconomic situations, poor family climate, and adverse childhood experiences. These childhood trauma experiences can drastically affect a child and their future. It is important as teacher to recognize the factors in order to help children throughout their school years as much as we can
Gluco-incretins regulate beta-cell glucose competence by epigenetic silencing of Fxyd3 expression.
BACKGROUND/AIMS: Gluco-incretin hormones increase the glucose competence of pancreatic beta-cells by incompletely characterized mechanisms.
METHODS: We searched for genes that were differentially expressed in islets from control and Glp1r-/-; Gipr-/- (dKO) mice, which show reduced glucose competence. Overexpression and knockdown studies; insulin secretion analysis; analysis of gene expression in islets from control and diabetic mice and humans as well as gene methylation and transcriptional analysis were performed.
RESULTS: Fxyd3 was the most up-regulated gene in glucose incompetent islets from dKO mice. When overexpressed in beta-cells Fxyd3 reduced glucose-induced insulin secretion by acting downstream of plasma membrane depolarization and Ca++ influx. Fxyd3 expression was not acutely regulated by cAMP raising agents in either control or dKO adult islets. Instead, expression of Fxyd3 was controlled by methylation of CpGs present in its proximal promoter region. Increased promoter methylation reduced Fxyd3 transcription as assessed by lower abundance of H3K4me3 at the transcriptional start site and in transcription reporter assays. This epigenetic imprinting was initiated perinatally and fully established in adult islets. Glucose incompetent islets from diabetic mice and humans showed increased expression of Fxyd3 and reduced promoter methylation.
CONCLUSIONS/INTERPRETATION: Because gluco-incretin secretion depends on feeding the epigenetic regulation of Fxyd3 expression may link nutrition in early life to establishment of adult beta-cell glucose competence; this epigenetic control is, however, lost in diabetes possibly as a result of gluco-incretin resistance and/or de-differentiation of beta-cells that are associated with the development of type 2 diabetes
\u3ci\u3eStaphylococcus aureus\u3c/i\u3e Hyaluronidase Is a CodY-Regulated Virulence Factor
Staphylococcus aureus is a Gram-positive pathogen that causes a diverse range of bacterial infections. Invasive S. aureus strains secrete an extensive arsenal of hemolysins, immunomodulators, and exoenzymes to cause disease. Our studies have focused on the secreted enzyme hyaluronidase (HysA), which cleaves the hyaluronic acid polymer at the β-1,4 glycosidic bond. In the study described in this report, we have investigated the regulation and contribution of this enzyme to S. aureus pathogenesis. Using the Nebraska Transposon Mutant Library (NTML), we identified eight insertions that modulate extracellular levels of HysA activity. Insertions in the sigB operon, as well as in genes encoding the global regulators SarA and CodY, significantly increased HysA protein levels and activity. By altering the availability of branched-chain amino acids, we further demonstrated CodY-dependent repression of HysA activity. Additionally, through mutation of the CodY binding box upstream of hysA, the repression of HysA production was lost, suggesting that CodY is a direct repressor of hysA expression. To determine whether HysA is a virulence factor, a ΔhysA mutant of a community-associated methicillin-resistant S. aureus (CA-MRSA) USA300 strain was constructed and found to be attenuated in a neutropenic, murine model of pulmonary infection. Mice infected with this mutant strain exhibited a 4-log-unit reduction in bacterial burden in their lungs, as well as reduced lung pathology and increased levels of pulmonary hyaluronic acid, compared to mice infected with the wild-type, parent strain. Taken together, these results indicate that S. aureus hyaluronidase is a CodY-regulated virulence factor
Spin readout of a CMOS quantum dot by gate reflectometry and spin-dependent tunnelling
Silicon spin qubits are promising candidates for realising large scale quantum processors, benefitting from a magnetically quiet host material and the prospects of leveraging the mature silicon device fabrication industry. We report the measurement of an electron spin in a singly-occupied gate-defined quantum dot, fabricated using CMOS compatible processes at the 300 mm wafer scale. For readout, we employ spin-dependent tunneling combined with a low-footprint single-lead quantum dot charge sensor, measured using radiofrequency gate reflectometry. We demonstrate spin readout in two devices using this technique, obtaining valley splittings in the range 0.5-0.7 meV using excited state spectroscopy, and measure a maximum electron spin relaxation time () of s at 1 Tesla. These long lifetimes indicate the silicon nanowire geometry and fabrication processes employed here show a great deal of promise for qubit devices, while the spin-readout method demonstrated here is well-suited to a variety of scalable architectures
Magnetic stress as a driving force of structural distortions: the case of CrN
We show that the observed transition from rocksalt to orthorhombic P
symmetry in CrN can be understood in terms of stress anisotropy. Using local
spin density functional theory, we find that the imbalance between stress
stored in spin-paired and spin-unpaired Cr nearest neighbors causes the
rocksalt structure to be unstable against distortions and justifies the
observed antiferromagnetic ordering. This stress has a purely magnetic origin,
and may be important in any system where the coupling between spin ordering and
structure is strong.Comment: 4 pages (two columns) 4 figure
Analysis of the dynamic co-expression network of heart regeneration in the zebrafish.
The zebrafish has the capacity to regenerate its heart after severe injury. While the function of a few genes during this process has been studied, we are far from fully understanding how genes interact to coordinate heart regeneration. To enable systematic insights into this phenomenon, we generated and integrated a dynamic co-expression network of heart regeneration in the zebrafish and linked systems-level properties to the underlying molecular events. Across multiple post-injury time points, the network displays topological attributes of biological relevance. We show that regeneration steps are mediated by modules of transcriptionally coordinated genes, and by genes acting as network hubs. We also established direct associations between hubs and validated drivers of heart regeneration with murine and human orthologs. The resulting models and interactive analysis tools are available at http://infused.vital-it.ch. Using a worked example, we demonstrate the usefulness of this unique open resource for hypothesis generation and in silico screening for genes involved in heart regeneration
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Co-infecting microbes dramatically alter pathogen gene essentiality during polymicrobial infection
Identifying genes required by pathogens during infection is critical for antimicrobial development. Here, we used a Monte Carlo simulation-based method to analyze high-throughput transposon sequencing data to determine the role of infection site and co-infecting microbes on the in vivo ‘essential’ genome of Staphylococcus aureus. We discovered that co-infection of murine surgical wounds with Pseudomonas aeruginosa results in conversion of ~25% of the in vivo S. aureus mono-culture essential genes to non-essential. Furthermore, 182 S. aureus genes are uniquely essential during co-infection. These “Community Dependent Essential” (CoDE) genes illustrate the importance of studying pathogen gene essentiality in polymicrobial communities
Competition between Magnetic and Structural Transition in CrN
CrN is observed to undergo a paramagnetic to antiferromagnetic transition
accompanied by a shear distortion from cubic NaCl-type to orthorhombic
structure. Our first-principle plane wave and ultrasoft pseudopotential
calculations confirm that the distorted antiferromagnetic phase with spin
configuration arranged in double ferromagnetic sheets along [110] is the most
stable. Antiferromagnetic ordering leads to a large depletion of states around
Fermi level, but it does not open a gap. Simultaneous occurence of structural
distortion and antiferromagnetic order is analyzed.Comment: 10 pages, 10 figure
Rapid cryogenic characterisation of 1024 integrated silicon quantum dots
Quantum computers are nearing the thousand qubit mark, with the current focus
on scaling to improve computational performance. As quantum processors grow in
complexity, new challenges arise such as the management of device variability
and the interface with supporting electronics. Spin qubits in silicon quantum
dots are poised to address these challenges with their proven control
fidelities and potential for compatibility with large-scale integration. Here,
we demonstrate the integration of 1024 silicon quantum dots with on-chip
digital and analogue electronics, all operating below 1 K. A high-frequency
analogue multiplexer provides fast access to all devices with minimal
electrical connections, enabling characteristic data across the quantum dot
array to be acquired in just 5 minutes. We achieve this by leveraging
radio-frequency reflectometry with state-of-the-art signal integrity, reaching
a minimum integration time of 160 ps. Key quantum dot parameters are extracted
by fast automated machine learning routines to assess quantum dot yield and
understand the impact of device design. We find correlations between quantum
dot parameters and room temperature transistor behaviour that may be used as a
proxy for in-line process monitoring. Our results show how rapid large-scale
studies of silicon quantum devices can be performed at lower temperatures and
measurement rates orders of magnitude faster than current probing techniques,
and form a platform for the future on-chip addressing of large scale qubit
arrays.Comment: Main text: 14 pages, 8 figures, 1 table Supplementary: 8 pages, 6
figure
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