623 research outputs found
Application of High Conductive Nanoparticles to Enhance Thermal and Mechanical Properties of Wood Composite
In the present work three different types of nanofillers such as multiwalled carbon nanotubes (MWCNTs), aluminum oxide nanoparticles and nanosize activated charcoal were mixed with UF resin and used in the preparation of medium density fiberboard(MDF). The process has improved heat transfer during hot pressing and achieved proper curing due to enhanced thermo physical properties of wood fibers. To improve the dispersion of nanofillers into UF matrix, high speed mechanical stirring and ultrasonic treatments were used. The MWCNTs were oxidized with nitric acid and the functional groups formed on its surface improved the dispersion and interaction with UF matrix. The dispersion of nanofillers in UF resin matrix was confirmed with XRD, FESEM, and DMA tests undertaken. The mixing of MWCNTs and Aluminum oxide with UF resin have reduced the curing time due to enhanced thermal conductivity of MDF matrix. The heat transfer during hot pressing of MDF improved significantly with the addition of MWCNTs and Al2O3 nanoparticle and activated charcoal did not have much effect on heat transfer. The curing rate of UF resin improved with all the three nanofillers, as the activation energy of UF curing decrease as shown by the DSC results. The physical and mechanical properties of MDF have improved significantly with MWCNTs and Al2O3 nanoparticle. The activated charcoal has significantly decreased the formaldehyde emission of MDF
Venezuelan equine encephalitis virus infection causes modulation of inflammatory and immune response genes in mouse brain
<p>Abstract</p> <p>Background</p> <p>Neurovirulent Venezuelan equine encephalitis virus (VEEV) causes lethal encephalitis in equines and is transmitted to humans by mosquitoes. VEEV is highly infectious when transmitted by aerosol and has been developed as a bio-warfare agent, making it an important pathogen to study from a military and civilian standpoint. Molecular mechanisms of VEE pathogenesis are poorly understood. To study these, the gene expression profile of VEEV infected mouse brains was investigated. Changes in gene expression were correlated with histological changes in the brain. In addition, a molecular framework of changes in gene expression associated with progression of the disease was studied.</p> <p>Results</p> <p>Our results demonstrate that genes related to important immune pathways such as antigen presentation, inflammation, apoptosis and response to virus (<it>Cxcl10</it>, <it>CxCl11</it>, <it>Ccl5</it>, <it>Ifr7</it>, <it>Ifi27 Oas1b</it>, <it>Fcerg1</it>,<it>Mif</it>, <it>Clusterin and MHC class II) </it>were upregulated as a result of virus infection. The number of over-expressed genes (>1.5-fold level) increased as the disease progressed (from 197, 296, 400, to 1086 at 24, 48, 72 and 96 hours post infection, respectively).</p> <p>Conclusion</p> <p>Identification of differentially expressed genes in brain will help in the understanding of VEEV-induced pathogenesis and selection of biomarkers for diagnosis and targeted therapy of VEEV-induced neurodegeneration.</p
Role of adhesion molecules and inflammation in Venezuelan equine encephalitis virus infected mouse brain
<p>Abstract</p> <p>Background</p> <p>Neuroinvasion of Venezuelan equine encephalitis virus (VEEV) and subsequent initiation of inflammation in the brain plays a crucial role in the outcome of VEEV infection in mice. Adhesion molecules expressed on microvascular endothelial cells in the brain have been implicated in the modulation of the blood brain barrier (BBB) and inflammation in brain but their role in VEEV pathogenesis is not very well understood. In this study, we evaluated the expression of extracellular matrix and adhesion molecules genes in the brain of VEEV infected mice.</p> <p>Findings</p> <p>Several cell to cell adhesion molecules and extracellular matrix protein genes such as ICAM-1, VCAM-1, CD44, Cadherins, integrins, MMPs and Timp1 were differentially regulated post-VEEV infection. ICAM-1 knock-out (IKO) mice infected with VEEV had markedly reduced inflammation in the brain and demonstrated a delay in the onset of clinical symptoms of disease. A differential regulation of inflammatory genes was observed in the IKO mice brain compared to their WT counterparts.</p> <p>Conclusions</p> <p>These results improve our present understanding of VEEV induced inflammation in mouse brain.</p
Ovarian hyper stimulation syndrome in a spontaneous singleton pregnancy: a case report
Ovarian hyper stimulation syndrome (OHSS) is extremely rare in spontaneous pregnancies. Spontaneous OHSS can result from glycoprotein hormones stimulating follicle-stimulating hormone receptors (FSHR). Our case reinforces the importance of a prompt diagnosis and management in all pregnant patients presenting with acute abdomen and ovarian masses. We report a case of spontaneous singleton pregnancy at 12-week POG presented with abdominal distension and enlarged ovaries. Patient was successfully managed with supportive treatment comprise of intravenous (IV) Albumin, thromboprophylaxis, dopamine agonist and insulin sensitizer. Spontaneous OHSS should be included in the differential diagnosis of acute abdomen in pregnant women. Since spontaneous OHSS can be associated with life-threatening complications, it requires early diagnosis for successful management. The etiology should be determined in order to focus the treatment and avoid future complications.
Design considerations for surface plasmon resonance-based fiber-optic detection of human blood group
A fiber-optic surface plasmon resonance (SPR) sensor for the detection of human blood groups is proposed. Previous experimental results describing the wavelength-dependent refractive index variation of multiple samples of different blood groups are considered for theoretical calculations. The spectral interrogation method, along with silica fiber and silver layer, is considered. The sensor\u27s performance is closely analyzed in terms of shift in SPR wavelength and SPR curve width in order to optimize the design parameters for a reliable and accurate blood-group identifier. The sensor design parameters include silver layer thickness, fiber core diameter, sensing region length, and temperature variation. The results are explained in terms of light coupling and plasmon resonance condition. The proposed sensing probe is able to provide high sensitivity and accuracy of blood-group detection, thereby opening an easy and reliable window for medical applications
Inhibitory feedback from the motor circuit gates mechanosensory processing in C. elegans
Animals must integrate sensory cues with their current behavioral context to
generate a suitable response. How this integration occurs is poorly understood.
Previously we developed high throughput methods to probe neural activity in
populations of Caenorhabditis elegans and discovered that the animal's
mechanosensory processing is rapidly modulated by the animal's locomotion.
Specifically we found that when the worm turns it suppresses its
mechanosensory-evoked reversal response. Here we report that C. elegans use
inhibitory feedback from turning-associated neurons to provide this rapid
modulation of mechanosensory processing. By performing high-throughput
optogenetic perturbations triggered on behavior, we show that turning
associated neurons SAA, RIV and/or SMB suppress mechanosensory-evoked reversals
during turns. We find that activation of the gentle-touch mechanosensory
neurons or of any of the interneurons AIZ, RIM, AIB and AVE during a turn is
less likely to evoke a reversal than activation during forward movement.
Inhibiting neurons SAA, RIV and SMB during a turn restores the likelihood with
which mechanosensory activation evokes reversals. Separately, activation of
premotor interneuron AVA evokes reversals regardless of whether the animal is
turning or moving forward. We therefore propose that inhibitory signals from
SAA, RIV and/or SMB gate mechanosensory signals upstream of neuron AVA. We
conclude that C. elegans rely on inhibitory feedback from the motor circuit to
modulate its response to sensory stimuli on fast timescales. This need for
motor signals in sensory processing may explain the ubiquity in many organisms
of motor-related neural activity patterns seen across the brain, including in
sensory processing areas
A universal and stable metasurface for photonic quasi bound state in continuum coupled with two dimensional semiconductors
Strong coupling of excitons to optical cavity modes is of immense importance
to understanding the fundamental physics of quantum electrodynamics at the
nanoscale as well as for practical applications in quantum information
technologies. There have been several attempts at achieving strong coupling
between excitons in two dimensional semiconductors such as transition metal
dichalcogenides (TMDCs) and photonic quasi-bound states in the continuum
(BICs). We identify two gaps in the platforms for achieving strong coupling
between TMDC excitons and photonic quasi-BICs: firstly, in the studies so far,
different cavity architectures have been employed for coupling to different
TMDCs. This would mean that typically, the fabrication process flow for the
cavities will need to be modified as one moves from one TMDC to the other,
which can limit the technological progress in the field. Secondly, there has
been no discussion of the impact of fabrication imperfections in the studies on
strong coupling of these subsystems so far. In this work, we address these two
questions by optimizing a cavity with the same architecture which can couple to
the four typical TMDCs (MoS, WS, MoSe, WSe) and perform a
detailed investigation on the fabrication tolerance of the associated photonic
quasi-BICs and their impact on strong coupling
N-Terminal Extension and C-Terminal Domains Are Required for ABCB6/HMT-1 Protein Interactions, Function in Cadmium Detoxification, and Localization to the Endosomal-Recycling System in Caenorhabditis elegans
The chronic exposure of humans to toxic metals such as cadmium from food and air causes dysfunction of vital organs, neurodegenerative conditions, and cancer. In this regard, members of the ABCB sub-family of the ATP-binding cassette (ABC) transporter superfamily, ABCB6/HMT-1, are acutely required for the detoxification of heavy metals and are present in genomes of many organisms including the nematode worm, Caenorhabditis elegans and humans. We showed previously that C. elegans ABCB6/HMT-1 detoxifies cadmium, copper, and arsenic, and is expressed in liver-like cells, the coelomocytes, head neurons and intestinal cells, which are the cell types that are affected by heavy metal poisoning in humans. The subcellular localization of ABCB6/HMT-1 proteins is unclear. ABCB6/HMT-1 proteins have a distinguishing topology: in addition to one transmembrane domain and one nucleotide-binding domain, they possess a hydrophobic N-terminal extension (NTE) domain encompassing five to six transmembrane spans. The role of the NTE domain in the function of ABCB6/HMT-1 in the native organism remains to be investigated. We used a versatile, multicellular model system, C. elegans, to establish the subcellular localization of ABCB6/HMT-1 and refine its structure-function studies in the native organism. We show that ABCB6/HMT-1 localizes mainly to the apical recycling endosomes and, in part, to early and late endosomes of intestinal cells. We also show that ABCB6/HMT-1 lacking the NTE domain is mistargeted to the plasma membrane and is unable to confer cadmium resistance. Although the NTE domain is essential for ABCB6/HMT-1 interaction with itself, the absence of NTE does not fully prevent this interaction. As a result, ABCB6/HMT-1 lacking the NTE domain, and expressed in wild-type worms or co-expressed with the full-length polypeptide, inactivates and mistargets the full-length ABCB6/HMT-1. We also show that the 43 amino acid residue stretch at the COOH-terminus is required for the ABCB6/HMT-1 interaction with itself and cadmium detoxification function. These results suggest that both NTE and COOH-terminus must be present to allow the protein to interact with itself and confer cadmium resistance. Considering that ABCB6/HMT-1 proteins are highly conserved, this study advances our understanding of how these proteins function in cadmium resistance in different species. Furthermore, these studies uncover the role of the endosomal-recycling system in cadmium detoxification
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