Bounds for the natural frequencies of a plate subjected to a thermal gradient

Thermal gradient effects on vibrational frequencies of supported rectangular plat

Bounds for the eigenvalues of a simply- supported rectangular plate under a compressive stress varying linearly in the direction of loading

Upper bounds of eigenvalues of simply-supported rectangular plate using Rayleigh-Ritz metho

Upper and lower bounds for the eigenvalues of vibrating beams with linearly varying axial load

Upper and lower bounds for eigenvalues of vibrating beams and flat plates with varying axial loa

Ceramide and Related-Sphingolipid Levels Are Not Altered in Disease-Associated Brain Regions of APPSL and APPSL/PS1M146L Mouse Models of Alzheimer's Disease: Relationship with the Lack of Neurodegeneration?

There is evidence linking sphingolipid abnormalities, APP processing, and neuronal death in Alzheimer's disease (AD). We previously reported a strong elevation of ceramide levels in the brain of the APPSL/PS1Ki mouse model of AD, preceding the neuronal death. To extend these findings, we analyzed ceramide and related-sphingolipid contents in brain from two other mouse models (i.e., APPSL and APPSL/PS1M146L) in which the time-course of pathology is closer to that seen in most currently available models. Conversely to our previous work, ceramides did not accumulate in disease-associated brain regions (cortex and hippocampus) from both models. However, the APPSL/PS1Ki model is unique for its drastic neuronal loss coinciding with strong accumulation of neurotoxic Aβ isoforms, not observed in other animal models of AD. Since there are neither neuronal loss nor toxic Aβ species accumulation in APPSL mice, we hypothesized that it might explain the lack of ceramide accumulation, at least in this model

Iterative reconstruction optimisations for high angle cone-beam micro-CT

We address several acquisition questions that have arisen for the high cone-angle helical-scanning micro-CT facility developed at the Australian National University. These challenges are generally known in medical and industrial cone-beam scanners but can be neglected in these systems. For our large datasets, with more than 2048³ voxels, minimising the number of operations (or iterations) is crucial. Large cone-angles enable high signal-to-noise ratio imaging and a large helical pitch to be used. This introduces two challenges: (i) non-uniform resolution throughout the reconstruction, (ii) over-scan beyond the region-of-interest significantly increases required reconstructed volume size. Challenge (i) can be addressed by using a double-helix or lower pitch helix but both solutions slow down iterations. Challenge (ii) can also be improved by using a lower pitch helix but results in more projections slowing down iterations. This may be overcome using less projections per revolution but leads to more iterations required. Here we assume a given total time for acquisition and a given reconstruction technique (SART) and seek to identify the optimal trajectory and number of projections per revolution in order to produce the best tomogram, minimise reconstruction time required, and minimise memory requirements

Prevention of the β-amyloid peptide-induced inflammatory process by inhibition of double-stranded RNA-dependent protein kinase in primary murine mixed co-cultures

<p>Abstract</p> <p>Background</p> <p>Inflammation may be involved in the pathogenesis of Alzheimer's disease (AD). There has been little success with anti-inflammatory drugs in AD, while the promise of anti-inflammatory treatment is more evident in experimental models. A new anti-inflammatory strategy requires a better understanding of molecular mechanisms. Among the plethora of signaling pathways activated by β-amyloid (Aβ) peptides, the nuclear factor-kappa B (NF-κB) pathway could be an interesting target. In virus-infected cells, double-stranded RNA-dependent protein kinase (PKR) controls the NF-κB signaling pathway. It is well-known that PKR is activated in AD. This led us to study the effect of a specific inhibitor of PKR on the Aβ42-induced inflammatory response in primary mixed murine co-cultures, allowing interactions between neurons, astrocytes and microglia.</p> <p>Methods</p> <p>Primary mixed murine co-cultures were prepared in three steps: a primary culture of astrocytes and microglia for 14 days, then a primary culture of neurons and astrocytes which were cultured with microglia purified from the first culture. Before exposure to Aβ neurotoxicity (72 h), co-cultures were treated with compound C16, a specific inhibitor of PKR. Levels of tumor necrosis factor-α (TNFα), interleukin (IL)-1β, and IL-6 were assessed by ELISA. Levels of P_T451-PKR and activation of IκB, NF-κB and caspase-3 were assessed by western blotting. Apoptosis was also followed using annexin V-FITC immunostaining kit. Subcellular distribution of P_T451-PKR was assessed by confocal immunofluorescence and morphological structure of cells by scanning electron microscopy. Data were analysed using one-way ANOVA followed by a Newman-Keuls' post hoc test</p> <p>Results</p> <p>In these co-cultures, PKR inhibition prevented Aβ42-induced activation of IκB and NF-κB, strongly decreased production and release of tumor necrosis factor (TNFα) and interleukin (IL)-1β, and limited apoptosis.</p> <p>Conclusion</p> <p>In spite of the complexity of the innate immune response, PKR inhibition could be an interesting anti-inflammatory strategy in AD.</p

Long-term effect of parental selenium supplementation on the one-carbon metabolism in rainbow trout (Oncorhynchus mykiss) fry exposed to hypoxic stress

This study evaluated how different forms of selenium (Se) supplementation into rainbow trout broodstock diets modified the one-carbon metabolism of the progeny after the beginning of exogenous feeding and followed by hypoxia challenge. The progeny of three groups of rainbow trout broodstock fed either a control diet (Se level: 0·3 µg/g) or a diet supplemented with inorganic sodium selenite (Se level: 0·6 µg/g) or organic hydroxy-selenomethionine (Se level: 0·6 µg/g) was cross-fed with diets of similar Se composition for 11 weeks. Offspring were sampled either before or after being subjected to an acute hypoxic stress (1·7 mg/l dissolved oxygen) for 30 min. In normoxic fry, parental Se supplementation allowed higher glutathione levels compared with fry originating from parents fed the control diet. Parental hydroxy-selenomethionine treatment also increased cysteine and cysteinyl–glycine concentrations in fry. Dietary Se supplementation decreased glutamate–cysteine ligase (cgl) mRNA levels. Hydroxy-selenomethionine feeding also lowered the levels of some essential free amino acids in muscle tissue. Supplementation of organic Se to parents and fry reduced betaine-homocysteine S-methyltransferase (bhmt) expression in fry. The hypoxic stress decreased whole-body homocysteine, cysteine, cysteinyl-glycine and glutathione levels. Together with the higher mRNA levels of cystathionine beta-synthase (cbs), a transsulphuration enzyme, this suggests that under hypoxia, glutathione synthesis through transsulphuration might have been impaired by depletion of a glutathione precursor. In stressed fry, S-adenosylmethionine levels were significantly decreased, but S-adenosylhomocysteine remained stable. Decreased bhmt and adenosylmethionine decarboxylase 1a (amd1a) mRNA levels in stressed fry suggest a nutritional programming by parental Se also on methionine metabolism of rainbow trout.publishedVersio

Parental selenium nutrition affects the one-carbon metabolism and the hepatic dna methylation pattern of rainbow trout (Oncorhynchus mykiss) in the progeny

Selenium is an essential micronutrient and its metabolism is closely linked to the methionine cycle and transsulfuration pathway. The present study evaluated the effect of two different selenium supplements in the diet of rainbow trout (Onchorhynchus mykiss) broodstock on the one-carbon metabolism and the hepatic DNA methylation pattern in the progeny. Offspring of three parental groups of rainbow trout, fed either a control diet (NC, basal Se level: 0.3 mg/kg) or a diet supplemented with sodium selenite (SS, 0.8 mg Se/kg) or hydroxy-selenomethionine (SO, 0.7 mg Se/kg), were collected at swim-up fry stage. Our findings suggest that parental selenium nutrition impacted the methionine cycle with lower free methionine and S-adenosylmethionine (SAM) and higher methionine synthase (mtr) mRNA levels in both selenium-supplemented treatments. DNA methylation profiling by reduced representation bisulfite sequencing (RRBS) identified differentially methylated cytosines (DMCs) in offspring livers. These DMCs were related to 6535 differentially methylated genes in SS:NC, 6890 in SO:NC and 7428 in SO:SS, respectively. Genes with the highest methylation difference relate, among others, to the neuronal or signal transmitting and immune system which represent potential targets for future studies.publishedVersio

Enhanced Shadow Retargeting with Light-Source Estimation Using Flat Fresnel Lenses

Shadow-retargeting maps depict the appearance of real shadows to virtual shadows given corresponding deformation of scene geometry, such that appearance is seamlessly maintained. By performing virtual shadow reconstruction from unoccluded real-shadow samples observed in the camera frame, this method efficiently recovers deformed shadow appearance. In this manuscript, we introduce a light-estimation approach that enables light-source detection using flat Fresnel lenses that allow this method to work without a set of pre-established conditions. We extend the adeptness of this approach by handling scenarios with multiple receiver surfaces and a non-grounded occluder with high accuracy. Results are presented on a range of objects, deformations, and illumination conditions in real-time Augmented Reality (AR) on a mobile device. We demonstrate the practical application of the method in generating otherwise laborious in-betweening frames for 3D printed stop-motion animatio