158 research outputs found
Flexural behavior of LVL made from Australian radiata pine
As a commonly used engineering wood in modern timber constructions, laminated veneer lumber (LVL), produced from small-diameter wood, short-dimension wood, or fast-growing wood, significantly enhances material properties to meet the mechanical and physical requirements in structural engineering. This study aims to investigate the feasibility of utilizing fast-growing Australian radiata pine to produce structural LVL, providing essential theoretical support for its application in civil engineering. The investigation focuses specifically on Australian radiata pine LVL (RP-LVL) and involves a systematic experimental study to assess the bending performance of RP-LVL under various bending directions and specimen sizes. The findings reveal that the edgewise bending strength of RP-LVL is comparatively lower than its flatwise bending strength. Nevertheless, RP-LVL exhibits superior bending strength compared to conventional glulam and dimensional lumber, rendering it an attractive and suitable building material for achieving enhanced bending performance in flexure members. Moreover, the study identifies significant influences of height and width on the bending strength of RP-LVL. Consequently, prediction method is proposed to calculate the bending strength of RP-LVL, considering these size influences. Importantly, the size influences on bending strength are quantified to provide a comprehensive evaluation of the bending capacity of RP-LVL flexure members
Identification of morphological fingerprint in perinatal brains using quasi-conformal mapping and contrastive learning
The morphological fingerprint in the brain is capable of identifying the
uniqueness of an individual. However, whether such individual patterns are
present in perinatal brains, and which morphological attributes or cortical
regions better characterize the individual differences of ne-onates remain
unclear. In this study, we proposed a deep learning framework that projected
three-dimensional spherical meshes of three morphological features (i.e.,
cortical thickness, mean curvature, and sulcal depth) onto two-dimensional
planes through quasi-conformal mapping, and employed the ResNet18 and
contrastive learning for individual identification. We used the cross-sectional
structural MRI data of 682 infants, incorporating with data augmentation, to
train the model and fine-tuned the parameters based on 60 infants who had
longitudinal scans. The model was validated on 30 longitudinal scanned infant
data, and remarkable Top1 and Top5 accuracies of 71.37% and 84.10% were
achieved, respectively. The sensorimotor and visual cortices were recognized as
the most contributive regions in individual identification. Moreover, the
folding morphology demonstrated greater discriminative capability than the
cortical thickness, which could serve as the morphological fingerprint in
perinatal brains. These findings provided evidence for the emergence of
morphological fingerprints in the brain at the beginning of the third
trimester, which may hold promising implications for understanding the
formation of in-dividual uniqueness in the brain during early development
Propionate Protects Haloperidol-Induced Neurite Lesions Mediated by Neuropeptide Y
Haloperidol is a commonly used antipsychotic drug for treating schizophrenia. Clinical imaging studies have found that haloperidol can cause volume loss of human brain tissue, which is supported by animal studies showing that haloperidol reduces the number of synaptic spines. The mechanism remains unknown. Gut microbiota metabolites, short chain fatty acids including propionate, are reported to have neuroprotective effect and influence gene expression. This study aims to investigate the effect and mechanism of propionate in the protection of neurite lesion induced by haloperidol. This study showed that 10 μM haloperidol (clinical relevant dose) impaired neurite length in human blastoma SH-SY5Y cells, which were confirmed by using primary mouse striatal spiny neurons. We found that haloperidol impaired neurite length were accompanied by a decreased neuropeptide Y (NPY) expression, but no effect on GSK3β signaling. Importantly, this project research found that propionate was capable of protecting against haloperidol-induced neurite lesions and preventing NPY reduction. To confirm this finding, we used specific siRNAs targeting NPY which blocked the protective effect of propionate on haloperidol-induced neurite lesions. Furthermore, since NPY is regulated by the nuclear transcription factor CREB, we measured pCREB that was decreased by haloperidol and was normalized by propionate. Therefore, propionate has a protective effect against pCREB-NPY mediated haloperidol-induced neurite lesions
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Structure of KAP1 tripartite motif identifies molecular interfaces required for retroelement silencing.
Transcription of transposable elements is tightly regulated to prevent genome damage. KRAB domain-containing zinc finger proteins (KRAB-ZFPs) and KRAB-associated protein 1 (KAP1/TRIM28) play a key role in regulating retrotransposons. KRAB-ZFPs recognize specific retrotransposon sequences and recruit KAP1, inducing the assembly of an epigenetic silencing complex, with chromatin remodeling activities that repress transcription of the targeted retrotransposon and adjacent genes. Our biophysical and structural data show that the tripartite motif (TRIM) of KAP1 forms antiparallel dimers, which further assemble into tetramers and higher-order oligomers in a concentration-dependent manner. Structure-based mutations in the B-box 1 domain prevent higher-order oligomerization without significant loss of retrotransposon silencing activity, indicating that, in contrast to other TRIM-family proteins, self-assembly is not essential for KAP1 function. The crystal structure of the KAP1 TRIM dimer identifies the KRAB domain binding site in the coiled-coil domain near the dyad. Mutations at this site abolished KRAB binding and transcriptional silencing activity of KAP1. This work identifies the interaction interfaces in the KAP1 TRIM responsible for self-association and KRAB binding and establishes their role in retrotransposon silencing.This work was supported by Wellcome Trust through Senior Research Fellowship 101908/Z/13/Z and PhD Studentship 205833/Z/16/Z
Audio Deepfake Detection Based on a Combination of F0 Information and Real Plus Imaginary Spectrogram Features
Recently, pioneer research works have proposed a large number of acoustic
features (log power spectrogram, linear frequency cepstral coefficients,
constant Q cepstral coefficients, etc.) for audio deepfake detection, obtaining
good performance, and showing that different subbands have different
contributions to audio deepfake detection. However, this lacks an explanation
of the specific information in the subband, and these features also lose
information such as phase. Inspired by the mechanism of synthetic speech, the
fundamental frequency (F0) information is used to improve the quality of
synthetic speech, while the F0 of synthetic speech is still too average, which
differs significantly from that of real speech. It is expected that F0 can be
used as important information to discriminate between bonafide and fake speech,
while this information cannot be used directly due to the irregular
distribution of F0. Insteadly, the frequency band containing most of F0 is
selected as the input feature. Meanwhile, to make full use of the phase and
full-band information, we also propose to use real and imaginary spectrogram
features as complementary input features and model the disjoint subbands
separately. Finally, the results of F0, real and imaginary spectrogram features
are fused. Experimental results on the ASVspoof 2019 LA dataset show that our
proposed system is very effective for the audio deepfake detection task,
achieving an equivalent error rate (EER) of 0.43%, which surpasses almost all
systems
Curdlan Prevents the Cognitive Deficits Induced by a High-Fat Diet in Mice via the Gut-Brain Axis
A high-fat (HF) diet is a major predisposing factor of neuroinflammation and cognitive deficits. Recently, changes in the gut microbiota have been associated with neuroinflammation and cognitive impairment, through the gut-brain axis. Curdlan, a bacterial polysaccharide widely used as food additive, has the potential to alter the composition of the microbiota and improve the gut-brain axis. However, the effects of curdlan against HF diet-induced neuroinflammation and cognitive decline have not been investigated. We aimed to evaluate the neuroprotective effect and mechanism of dietary curdlan supplementation against the obesity-associated cognitive decline observed in mice fed a HF diet. C57Bl/6J male mice were fed with either a control, HF, or HF with curdlan supplementation diets for 7 days (acute) or 15 weeks (chronic). We found that acute curdlan supplementation prevented the gut microbial composition shift induced by HF diet. Chronic curdlan supplementation prevented cognitive declines induced by HF diet. In addition, curdlan protected against the HF diet-induced abnormities in colonic permeability, hyperendotoxemia, and colonic inflammation. Furthermore, in the prefrontal cortex (PFC) and hippocampus, curdlan mitigated microgliosis, neuroinflammation, and synaptic impairments induced by a HF diet. Thus, curdlan-as a food additive and prebiotic-can prevent cognitive deficits induced by HF diet via the colon-brain axis
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