The effect of the Si–H bond on the gas-phase reaction chemistry of trimethylsilane in the hot-wire chemical vapor deposition (HWCVD) process has been studied by examining its decomposition on a hot ...tungsten filament and the secondary gas-phase reactions in a reactor using a soft laser ionization source coupled with mass spectrometry. Trimethylsilane decomposes on the hot filament via Si–H and Si-CH3 bond cleavages. A short-chain mechanism is found to dominate in the secondary reactions in the reactor. It has been shown that the hydrogen abstractions of both Si–H and C–H occur simultaneously, with the abstraction of Si–H being favored. Tetramethylsilane and hexamethyldisilane are the two major products formed from the radical recombination reactions in the termination steps. Three methyl-substituted disilacyclobutane molecules, i.e., 1,3-dimethyl-1,3-disilacyclobutane, 1,1,3-trimethyl-1,3-disilacyclobutane, and 1,1,3,3-tetramethyl-1,3-disilacyclobutane are also produced in reactor from the cycloaddition reactions of methyl-substituted silene species. Compared to tetramethylsilane and hexamethyldisilane, a common feature with trimethylsilane is that the short-chain mechanism still dominates. However, a more active involvement of the reactive silene intermediates has been found with trimethylsilane.
Abstract Background Ticagrelor has been demonstrated to provide a more rapid and powerful inhibition of platelet aggregation compared with clopidogrel in coronary artery disease (CAD) patients. In ...our previous study, we found that half-dose ticagrelor produced similar inhibitory effects on platelet aggregation as standard-dose ticagrelor and exerted significantly stronger effects than clopidogrel in Chinese patients with non-ST-elevation ACS. Therefore, we performed this study to observe the efficacy of one-quarter standard-dose ticagrelor in comparison to standard-dose clopidogrel in Chinese patients with stable CAD. Methods In a randomized, single-blind, crossover trial, 30 patients with stable CAD were randomized to one-quarter standard-dose ticagrelor (22.5 mg BID for 7 days) or standard-dose clopidogrel (75 mg QD for 7 days). Following a 2-week washout period, patients switched regimens. Light transmission aggregometry (LTA) and VerifyNow assay were used to measure platelet function. Results The platelet aggregation rate (PAgR) was obviously lower with ticagrelor than clopidogrel (17.70%±12.67% versus 27.63%±13.10%, P < 0.05). The % inhibition levels in the ticagrelor group exhibited significantly greater than that in the clopidogrel group (65.33%±21.31% versus 36.23%±23.01%, P < 0.01). PRU values in the ticagrelor group were dramatically lower than that in the clopidogrel group (87.03 ± 51.38 versus 163.77 ± 58.66, P < 0.01). High-platelet reactivity (HPR) (≥ 208 PRU) was 0% with ticagrelor and 16.67% with clopidogrel. Conclusions one-quarter standard-dose ticagrelor provided greater degree of platelet inhibition than standard-dose clopidogrel in Chinese patients with stable CAD.
Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of ...R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.
Abstract
The discovery of high-temperature superconductivity in quasi-one-dimensional spin ladder compound BaFe
2
S
3
has attracted great attention for facilitating study on the interplay among ...crystalline dimensionality, magnetism, and superconductivity. Here, we report a systematic study on the doping-dependent structure, susceptibility, and high-pressure properties of BaFe
2
(S
1−
x
Se
x
)
3
. The structural analysis manifests a structural transition within the doping level of 0.18 <
x
< 0.29. Accompanied with this structural transition, the magnetic susceptibility behaviors change substantially, in line with the antiferromagnetic structure change from the stripe-type to the block-type. Furthermore, obvious spin glassy behaviors are observed in the low-temperature region for
x
⩾ 0.29. High-pressure study has revealed an explicit superconductivity signal in the undoped BaFe
2
S
3
with a pressure of about 12.6 GPa, while no bulk superconductivity is observed for the Se-doped samples. Analysis of the pressure-dependent resistance behavior indicates a pressure-induced electronic phase transition around 18 GPa for all Se-doped samples. Finally, we have discussed the possible origin for the pressure-induced superconductivity in BaFe
2
(S
1−
x
Se
x
)
3
.
The Synthetic Aperture Radar Interferometry (InSAR) technique can quickly obtain millimeter-level surface deformation in urban areas with high coherence. However, expanding the application of time ...series InSAR in non-urban areas is an important research focus. An improved SBAS-InSAR analysis approach is applied in this study to present the surface displacement along two expressways under construction. Taking the Kejiao and Yicheng Highway in the Shenzhen Shanwei Special Cooperation Zone as examples, the deformation along the highways under construction and the surrounding ground objects is revealed. Moreover, the time series displacements and construction conditions are combined to explain the possible mechanisms behind the different displacements of various ground objects along the expressways. The results show that the climate, environment, and construction conditions of the cooperation zone had an impact on the deformation of various ground objects along the route. Compared to traditional PS-InSAR methods, the density and accuracy of coherence points are improved, which better overcomes the spatiotemporal incoherence effects in non-urban areas.
Using a $3.19\text{ }\text{ }{\mathrm{fb}}^{{-}1}$ data sample collected at an ${e}^{+}{e}^{{-}}$ center-of-mass energy of ${E}_{\mathrm{cm}}=4.178\text{ }\text{ }\mathrm{GeV}$ with the BESIII ...detector, we measure the branching fraction of the leptonic decay ${D}_{s}^{+}{\rightarrow}{{\mu}}^{+}{{\nu}}_{{\mu}}$ to be ${\mathcal{B}}_{{D}_{s}^{+}{\rightarrow}{{\mu}}^{+}{{\nu}}_{{\mu}}}=(5.49\pm{}0.1{6}_{\text{stat}}\pm{}0.1{5}_{\text{syst}})\times{}{10}^{{-}3}$. Combining our branching fraction with the masses of the ${D}_{s}^{+}$ and ${{\mu}}^{+}$ and the lifetime of the ${D}_{s}^{+}$, we determine ${f}_{{D}_{s}^{+}}|{V}_{cs}|=246.2\pm{}3.{6}_{\text{stat}}\pm{}3.{5}_{\text{syst}}\text{ }\text{ }\mathrm{MeV}$. Using the $c{\rightarrow}s$ quark mixing matrix element $|{V}_{cs}|$ determined from a global standard model fit, we evaluate the ${D}_{s}^{+}$ decay constant ${f}_{{D}_{s}^{+}}=252.9\pm{}3.{7}_{\text{stat}}\pm{}3.{6}_{\text{syst}}\text{ }\text{ }\mathrm{MeV}$. Alternatively, using the value of ${f}_{{D}_{s}^{+}}$ calculated by lattice quantum chromodynamics, we find $|{V}_{cs}|=0.985\pm{}0.01{4}_{\text{stat}}\pm{}0.01{4}_{\text{syst}}$. These values of ${\mathcal{B}}_{{D}_{s}^{+}{\rightarrow}{{\mu}}^{+}{{\nu}}_{{\mu}}}$, ${f}_{{D}_{s}^{+}}|{V}_{cs}|$, ${f}_{{D}_{s}^{+}}$ and $|{V}_{cs}|$ are each the most precise results to date.
PD-1/PD-L1 inhibitors are a relatively new class of immunotherapeutic drugs approved for advanced non-small-cell lung cancer. The purpose of this study was to conduct a network meta-analysis to ...compare the safety and efficacy of these immune checkpoint inhibitors (ICIs).
We used Bayesian network meta-analysis methods to evaluate the efficacy and safety of the included treatments. We further analyzed subgroups based on PD-L1 expression level, histology type, and line of the treatment setting.
We identified 19 RCTs, including 12,753 patients. In the analysis of all-comers, the pembrolizumab/chemotherapy combination ranked best for overall survival (OS) and progression-free survival (PFS). Durvalumab was the only ICI treatment that showed no benefit over chemotherapy. In the first-line setting only, in terms of OS, atezolizumab, pembrolizumab/chemotherapy, and nivolumab/ipilimumab ranked as the best treatments for patients with PD-L1 expression levels of ≥50%, 1-49%, and <1%, respectively. Nivolumab, atezolizumab, pembrolizumab, and durvalumab all had lower odds of grade 3 or greater treatment-related adverse events (TRAEs) compared to chemotherapy. With the addition of chemotherapy to any ICI regimen, the odds of TRAEs increased in a considerable and statistically significant way.
While the pembrolizumab/chemotherapy combination was the most effective therapy in the overall cohort of all-comers, treatment preferences varied by treatment-line setting, tumor characteristics, and outcome of interest. In the first-line setting, the most effective treatments for patients with PD-L1 expressions of ≥50%, 1-49%, and <1% were atezolizumab, pembrolizumab/chemotherapy, and nivolumab/ipilimumab, respectively.
Highland barley, also called “qingke” in Tibetan, is mainly cultivated in the Tibetan Plateau of China and has been used as a major staple food for Tibetans. Recently, Fusarium head blight (FHB) of ...qingke was frequently observed around the Brahmaputra River in Tibet. Considering the importance of qingke for Tibetans, the assessment of Fusarium mycotoxin contamination is essential for food safety. In this study, a total of 150 freshly harvested qingke grain samples were obtained from three regions around the Brahmaputra River in Tibet (China) in 2020. The samples were investigated for the occurrence of 20
Fusarium
mycotoxins using high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS). The most frequently occurring mycotoxin was enniatin B (ENB) (46%), followed by enniatin B
1
(ENB
1
) (14.7%), zearalenone (ZEN) (6.0%), enniatin A
1
(ENA
1
) (3.3%), enniatin A (ENA) (1.3%), beauvericin (BEA) (0.7%), and nivalenol (NIV) (0.7%). Due to the increase in altitude, the cumulative precipitation level and average temperature decreased from the downstream to the upstream of the Brahmaputra River; this directly correlated to the contamination level of ENB in qingke, which gradually decreased from downstream to upstream. In addition, the level of ENB in qingke obtained from qingke-rape rotation was significantly lower than that from qingke-wheat and qingke-qingke rotations (
p
< 0.05). These results disseminated the occurrence of
Fusarium
mycotoxins and provided further understanding of the effect of environmental factors and crop rotation on
Fusarium
mycotoxins.
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