13,291 research outputs found
The Regulatory Role of MeAIB in Protein Metabolism and the mTOR Signaling Pathway in Porcine Enterocytes.
Amino acid transporters play an important role in cell growth and metabolism. MeAIB, a transporter-selective substrate, often represses the adaptive regulation of sodium-coupled neutral amino acid transporter 2 (SNAT2), which may act as a receptor and regulate cellular amino acid contents, therefore modulating cellular downstream signaling. The aim of this study was to investigate the effects of MeAIB to SNAT2 on cell proliferation, protein turnover, and the mammalian target of rapamycin (mTOR) signaling pathway in porcine enterocytes. Intestinal porcine epithelial cells (IPEC)-J2 cells were cultured in a high-glucose Dulbecco's modified Eagle's (DMEM-H) medium with 0 or 5 mmoL/L System A amino acid analogue (MeAIB) for 48 h. Cells were collected for analysis of proliferation, cell cycle, protein synthesis and degradation, intracellular free amino acids, and the expression of key genes involved in the mTOR signaling pathway. The results showed that SNAT2 inhibition by MeAIB depleted intracellular concentrations of not only SNAT2 amino acid substrates but also of indispensable amino acids (methionine and leucine), and suppressed cell proliferation and impaired protein synthesis. MeAIB inhibited mTOR phosphorylation, which might be involved in three translation regulators, EIF4EBP1, IGFBP3, and DDIT4 from PCR array analysis of the 84 genes related to the mTOR signaling pathway. These results suggest that SNAT2 inhibition treated with MeAIB plays an important role in regulating protein synthesis and mTOR signaling, and provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine
Determining layer number of two dimensional flakes of transition-metal dichalcogenides by the Raman intensity from substrate
Transition-metal dichalcogenide (TMD) semiconductors have been widely studied
due to their distinctive electronic and optical properties. The property of TMD
flakes is a function of its thickness, or layer number (N). How to determine N
of ultrathin TMDs materials is of primary importance for fundamental study and
practical applications. Raman mode intensity from substrates has been used to
identify N of intrinsic and defective multilayer graphenes up to N=100.
However, such analysis is not applicable for ultrathin TMD flakes due to the
lack of a unified complex refractive index () from monolayer to bulk
TMDs. Here, we discuss the N identification of TMD flakes on the SiO/Si
substrate by the intensity ratio between the Si peak from 100-nm (or 89-nm)
SiO/Si substrates underneath TMD flakes and that from bare SiO/Si
substrates. We assume the real part of of TMD flakes as that of
monolayer TMD and treat the imaginary part of as a fitting
parameter to fit the experimental intensity ratio. An empirical ,
namely, , of ultrathin MoS, WS and WSe
flakes from monolayer to multilayer is obtained for typical laser excitations
(2.54 eV, 2.34 eV, or 2.09 eV). The fitted of MoS has
been used to identify N of MoS flakes deposited on 302-nm SiO/Si
substrate, which agrees well with that determined from their shear and
layer-breathing modes. This technique by measuring Raman intensity from the
substrate can be extended to identify N of ultrathin 2D flakes with N-dependent
. For the application purpose, the intensity ratio excited by
specific laser excitations has been provided for MoS, WS and
WSe flakes and multilayer graphene flakes deposited on Si substrates
covered by 80-110 nm or 280-310 nm SiO layer.Comment: 10 pages, 4 figures. Accepted by Nanotechnolog
Multi-mode control based on HSIC for double pendulum robot
Double pendulum robot has four equilibrium points: Down-Down, Down-Up, Up-Down, and Up-Up. Define the transfer control from one equilibrium point to another equilibrium point as acrobatic action of DPR, and there are total of 20 acrobatic actions. This paper proposes the multi-mode control algorithm based on Human Simulated Intelligent Control theory for the realization process of those acrobatic actions, which has the structure of multi sub-controllers and multi control modes. As an example, the acrobatic action from Down-Up to Up-Down is realized in simulation and real-time experiments, and the results demonstrate the effectiveness of the proposed algorithm
Segatron: Segment-Aware Transformer for Language Modeling and Understanding
Transformers are powerful for sequence modeling. Nearly all state-of-the-art
language models and pre-trained language models are based on the Transformer
architecture. However, it distinguishes sequential tokens only with the token
position index. We hypothesize that better contextual representations can be
generated from the Transformer with richer positional information. To verify
this, we propose a segment-aware Transformer (Segatron), by replacing the
original token position encoding with a combined position encoding of
paragraph, sentence, and token. We first introduce the segment-aware mechanism
to Transformer-XL, which is a popular Transformer-based language model with
memory extension and relative position encoding. We find that our method can
further improve the Transformer-XL base model and large model, achieving 17.1
perplexity on the WikiText-103 dataset. We further investigate the pre-training
masked language modeling task with Segatron. Experimental results show that
BERT pre-trained with Segatron (SegaBERT) can outperform BERT with vanilla
Transformer on various NLP tasks, and outperforms RoBERTa on zero-shot sentence
representation learning.Comment: Accepted by AAAI 202
Preclinical investigation of an innovative magnesium-based bone graft substitute for potential orthopaedic applications
SummaryDegradable or corrosive biometal is an attractive research and development (R&D) area in clinical orthopaedics. This study was designed to investigate biomechanical and biological properties of magnesium (Mg) and strontium (Sr) with a focus on Mg-based metals, including pure Mg and Mg–xwt% Sr (x = 0.25, x = 1.0, x = 1.5, x = 2.5) alloys, as potential bone graft substitutes in respect to their mechanical strength, corrosion resistance, and cytocompatibility for further optimization and establishing indications for relevant in vivo applications. Our data showed that the tensile and compressive strength increased with addition of Sr because of the Mg17Sr2 precipitation strengthen. Compared with commercially used bone graft substitutes, the mechanical properties of Mg–Sr alloys were close to those of cortical bone, and the compressive strength could reach 300 MPa, suggesting its potential application for load-bearing bone as bone defect filler. The corrosion rates of Mg–xwt% Sr alloys were controlled in the range of 0.05–0.07 mm/y, indicating feasibility of bone grafting and the in situ bone repair process. Moreover, Mg–Sr alloys also exhibit good cytocompatibility and antibacterial properties. Our innovation presented in this work supported in vivo clinical indication-based assessment of biodegradable Mg-based metals that could be potential candidates for bone graft substitutes for future orthopaedic applications
2-{[4-(Dimethylamino)benzylidene]amino}phenyl disulfide
In the title molecule, C30H30N4S2, the two benzene rings connected through the disulfide chain form a dihedral angle of 88.7 (1)°, and the two benzene rings in the benzylideneaniline fragments form dihedral angles of 34.0 (1) and 35.4 (1)°. The crystal packing exhibits no significantly short intermolecular contacts
Neuroprotective effects of traditional Chinese medicine in treating glaucoma:A Meta-analysis
AIM:To assess the neuroprotective effects of traditional Chinese medicine in the treatment of glaucoma. METHODS:The electronic bibliographic databases were searched,including Medline(1966-01/2011-03), EMbase(1996-2010), Cochrane library, Wanfang database,VIP(1999-2011), CNKI, the radomized controlled trials of TCM treatment compares with Western medicine treatment of the glaucoma were assembled Data were extracted and evaluated by two reciewers independently with a designed extraction formation by Meta-analysis based on the Cochrane net suggestion. RESULTS:A total of 8 theses written in Chinese were retrieved,including 719 patients.The results of Meta-analysis showed the combination therapy of TCM and western therapy significant improves the effect of neuroprotection(P<0.01). In order to boost and qualify the curative effects of the aucupuncture, more precise samples should be designed and a multi-research central need to be bulit. however, according to the existing cases, the evidences of the effectiveness are weak due to the limited numbers of samples and the methodological defect. CONCLUSION: The existing evidence supports the combination therapy of TCM and western medicine stronger than the only used of western medicine(P<0.01). But owing to the limited studies and few number of TCM treatment for glaucoma's neuroprotection, the large sample andmulticenter random ized controlled trial is still needed to verify the superiority of TCM for neuroproctive effect of glaucoma's teatment
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