1,045 research outputs found
Effects of gastrointestinal motility on obesity
Background: Changes of gastrointestinal motility, which are important related to the food digestion and absorption in the gastrointestinal tract, may be one of the factors in obesity-formation. Aims The changes of gastrointestinal motility were explored in the rats from diet-induced obesity (DIO), diet-induced obese resistant (DR) or control (CON) by diet intervention. Methods: After fed with a high fat diet (HFD), 100 male Sprague–Dawley rats were divided into DIO, DR and CON groups. The rats from DIO and DR groups were fed with HFD, and CON with a basic diet (BD) for 6 weeks. Body weight, energy intake, gastric emptying, intestinal transit, motility of isolated small intestine segments and colon’s function were measured in this study. Expression of interstitial cells of Cajal (ICCs) and enteric nervous system (ENS) - choline acetyltransferase (ChAT), vasoactive intestinal peptides (VIP), substance P (SP) and NADPH-d histochemistry of nitric oxide synthase (NOS) were determined by immunohistochemistry. Results: Body weight and intake energy in the DIO group were higher than those in the DR group (p < 0.05). Gastric emptying of DIO group rats (78.33 ± 4.95%) was significantly faster than that of DR group (51.79 ± 10.72%) (p < 0.01). The peak value of motility in rat’s duodenum from the DR group was significantly higher than that in the DIO group (p < 0.05). In addition, the expression of interstitial cells of Cajal (ICC), choline acetyltransferase (ChAT), substance P (SP), vasoactive intestinal peptides (VIP) and neuronal nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in the intestine of rats were significantly increased in the DIO group when compared to the DR group (p < 0.05). Conclusion: A faster gastric emptying, a weaker contraction of duodenum movement, and a stronger contraction and relaxation of ileum movement were found in the rats from the DIO group. It indicated that there has effect of gastrointestinal motility on obesity induced by HFD
Does political conflict affect bilateral trade or vice versa? Evidence from Sino-U.S. relations
This paper investigates the dynamic causal relationship between
Sino-U.S. political conflict and bilateral trade using a time-varying
(bootstrap) Granger full-sample causality test and sub-sample rolling
window estimation. The result indicates that Sino-U.S. political conflict
and bilateral trade may interact in various ways. Bilateral trade
has both positive and negative effects on political conflict in several
sub-phases, and in turn, political conflict has the same impacts on
bilateral trade. In general, the relationship between Sino-U.S. political
conflict and bilateral trade is not always consistent with the
model of Polachek, which states bilateral trade has significantly
reduced political conflict. In the face of a severe economic situation,
China and the U.S. government should strengthen trade cooperation
and seek common ground of economic interests in order to
expand the improvement of political relations
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Properties of Graphene: A Theoretical Perspective
In this review, we provide an in-depth description of the physics of
monolayer and bilayer graphene from a theorist's perspective. We discuss the
physical properties of graphene in an external magnetic field, reflecting the
chiral nature of the quasiparticles near the Dirac point with a Landau level at
zero energy. We address the unique integer quantum Hall effects, the role of
electron correlations, and the recent observation of the fractional quantum
Hall effect in the monolayer graphene. The quantum Hall effect in bilayer
graphene is fundamentally different from that of a monolayer, reflecting the
unique band structure of this system. The theory of transport in the absence of
an external magnetic field is discussed in detail, along with the role of
disorder studied in various theoretical models. We highlight the differences
and similarities between monolayer and bilayer graphene, and focus on
thermodynamic properties such as the compressibility, the plasmon spectra, the
weak localization correction, quantum Hall effect, and optical properties.
Confinement of electrons in graphene is nontrivial due to Klein tunneling. We
review various theoretical and experimental studies of quantum confined
structures made from graphene. The band structure of graphene nanoribbons and
the role of the sublattice symmetry, edge geometry and the size of the
nanoribbon on the electronic and magnetic properties are very active areas of
research, and a detailed review of these topics is presented. Also, the effects
of substrate interactions, adsorbed atoms, lattice defects and doping on the
band structure of finite-sized graphene systems are discussed. We also include
a brief description of graphane -- gapped material obtained from graphene by
attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic
Ochrocephalamine A, a new quinolizidine alkaloid from Oxytropis ochrocephala Bunge
One dimeric matrine-type alkaloid, ochrocephalamine A (1), was isolated from the poisonous plant Oxytropis ochrocephala Bunge. Its structure was elucidated by spectroscopic data and single-crystal X-ray diffraction. The insecticidal and cytotoxic activities of 1 were evaluated
11.4% Efficiency non-fullerene polymer solar cells with trialkylsilyl substituted 2D-conjugated polymer as donor
Simutaneously high open circuit voltage and high short circuit current density is a big challenge for achieving high efficiency polymer solar cells due to the excitonic nature of organic semdonductors. Herein, we developed a trialkylsilyl substituted 2D-conjugated polymer with the highest occupied molecular orbital level down-shifted by Si-C bond interaction. The polymer solar cells obtained by pairing this polymer with a non-fullerene acceptor demonstrated a high power conversion efficiency of 11.41% with both high open circuit voltage of 0.94 V and high short circuit current density of 17.32 mA cm(-2) benefitted from the complementary absorption of the donor and acceptor, and the high hole transfer efficiency from acceptor to donor although the highest occupied molecular orbital level difference between the donor and acceptor is only 0.11 eV. The results indicate that the alkylsilyl substitution is an effective way in designing high performance conjugated polymer photovoltaic materials.open
PF4 regulates neuronal ferroptosis in cerebral hemorrhage through CXCR3/PI3K/AKT/Nrf2 pathway
Inhibiting ferroptosis represents a promising strategy for managing neuronal injury caused by intracerebral hemorrhage (ICH). Platelet factor 4 (PF4), a chemokine with diverse biological functions, has an unclear role in ICH and its impact on neuronal ferroptosis. To investigate this, a hemin-induced injury model was established in PC12 cells in vitro, and an ICH model was created in vivo using IV collagenase injection. Hemin-treated PC12 cells were co-cultured with recombinant mouse PF4 (Rm-PF4) protein to examine the effects of PF4 on ferroptosis. Additionally, Rm-PF4 was administered intraperitoneally to ICH mice, and its influence on neurological dysfunction, brain edema, and neuronal ferroptosis was evaluated. Western blot analysis was employed to assess PF4 levels, CXCR3/phosphatidylinositol 3-kinase (PI3K)/AKT/nuclear factor erythroid-2-related factor 2 (Nrf2) pathway activation, and ferroptosis-related protein expression. PF4 levels were found to be reduced in both perihematomal brain tissues of ICH mice and hemin-treated PC12 cells. Treatment with Rm-PF4 decreased ferrous ion, malondialdehyde (MDA), and reactive oxygen species (ROS) levels, effectively inhibiting ferroptosis in PC12 cells. Furthermore, Rm-PF4 administration alleviated neurological dysfunction, neuronal damage, and brain edema while suppressing neuronal ferroptosis in ICH mice. Mechanistically, Rm-PF4 activated the CXCR3/PI3K/AKT/Nrf2 pathway, and this protective effect was diminished by a CXCR3 antagonist in both ICH mice and hemin-treated PC12 cells. In conclusion, PF4 mitigates ICH-induced neuronal ferroptosis in mouse models and PC12 cells by activating the CXCR3/PI3K/AKT/Nrf2 pathway
Diagnostic accuracy of multichannel intraluminal impedance-pH monitoring for gastroesophageal reflux-induced chronic cough
Objectives: To elucidate the accuracy and advantages of Multichannel intraluminal impedance-pH monitoring (MII-pH) in diagnosing gastroesophageal reflux-induced chronic cough (GERC). Methods: The patients with suspected GERC were recruited and underwent MII-pH, GERC was confirmed by subsequent anti-reflux treatment despite the findings of MII-pH. Its diagnostic accuracy in identifying GERC were evaluated by receiver operating characteristic (ROC) analysis and compared with that of 24-h esophageal pH monitoring. Results: Among 158 patients completing both MII-pH and anti-reflux therapy, GERC was diagnosed in 136 patients, including acid GERC in 96 patients (70.6%), non-acid GERC in 30 patients (22.0%), neither one of both GERC in 10 patients (7.4%). For the identification of GERC, MII-pH presented with the sensitivity of 92.6%, specificity of 63.6%, positive predictive value of 94.0%, negative predictive value of 58.3% and area under ROC curve of 0.863, which was totally superior to 24-h esophageal pH monitoring. As the essential criteria of MII-pH, esophageal acid exposure time and symptom associated probability had a limited diagnostic value when used alone, but improved greatly the diagnostic yield when used in combination, even with a suboptimal efficacy. Conclusion: MII-pH is a more sensitive test for identifying GERC, but with a suboptimal diagnostic efficacy
SMA1, a homolog of the splicing factor Prp28, has a multifaceted role in miRNA biogenesis in Arabidopsis
MicroRNAs (miRNAs) are a class of small non-coding RNAs that repress gene expression. In plants, the RNase III enzyme Dicer-like (DCL1) processes primary miRNAs (pri-miRNAs) into miRNAs. Here, we show that SMALL1 (SMA1), a homolog of the DEADbox pre-mRNA splicing factor Prp28, plays essential roles in miRNA biogenesis in Arabidopsis. A hypomorphic sma1-1 mutation causes growth defects and reduces miRNA accumulation correlated with increased target transcript levels. SMA1 interacts with the DCL1 complex and positively influences primiRNA processing. Moreover, SMA1 binds the promoter region of genes encoding pri-miRNAs (MIRs) and is required for MIR transcription. Furthermore, SMA1 also enhances the abundance of the DCL1 protein levels through promoting the splicing of the DCL1 pre-mRNAs. Collectively, our data provide new insights into the function of SMA1/Prp28 in regulating miRNA abundance in plants
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