1,184 research outputs found
Search for the Contamination Source of Butyltin Compounds in Wine:Β Agglomerated Cork Stoppers
A possible butyltin contamination source in wine was studied in this paper. Agglomerated cork stoppers, which were produced in Portugal, Spain, and Italy, used in wine bottles were examined. The domestic cork products, cork granules, and mucus used for cork products were also analyzed. The levels of mono- and dibutyltin compounds in corks were found in the range from <0.0024 to 3.3 and from <0.0029 to 6.7 mug of Sn/g, respectively. A low level of tributyltin contamination was also found in 2 of 31 tested samples. The presence of butyltin compounds in agglomerated cork stoppers was confirmed by GC-MS. Experimental results indicated that all overseas agglomerated cork stoppers studied contained mono- and/or dibutyltins. Butyltins were not detected in cork granules, mucus, most of the natural cork stoppers, and domestic agglomerated cork products. The concentrations of mono- and dibutyltins increased with the time in a 30-day experiment, showing that butyltin compounds can leach from agglomerated cork to the wine. When the butyltin concentrations in wine samples were compared with their levels in the corresponding agglomerated cork stoppers, a correlation was found. The potential harm of such food contamination was evaluated by the toxic research of butyltin compounds using Daphnia sp. as the experimental model
Highly Quantum-Confined InAs Nanoscale Membranes
Nanoscale size-effects drastically alter the fundamental properties of
semiconductors. Here, we investigate the dominant role of quantum confinement
in the field-effect device properties of free-standing InAs nanomembranes with
varied thicknesses of 5-50 nm. First, optical absorption studies are performed
by transferring InAs "quantum membranes" (QMs) onto transparent substrates,
from which the quantized sub-bands are directly visualized. These sub-bands
determine the contact resistance of the system with the experimental values
consistent with the expected number of quantum transport modes available for a
given thickness. Finally, the effective electron mobility of InAs QMs is shown
to exhibit anomalous field- and thickness-dependences that are in distinct
contrast to the conventional MOSFET models, arising from the strong quantum
confinement of carriers. The results provide an important advance towards
establishing the fundamental device physics of 2-D semiconductors
Postoperative Recovery Outcomes for Obese Patients Undergoing General Anesthesia: A Meta-Analysis of Randomized Controlled Trials
PurposeThis study was performed to assess the postoperative recovery outcomes in obese patients undergoing general anesthesia.MethodsThe eligible studies were identified from PubMed, EmBase, and the Cochrane library until December 2020. The standard mean differences (SMDs) with 95% confidence intervals (CIs) were used to calculate the role of desflurane, sevoflurane, and propofol on recovery outcomes, and the analyses using the random-effects model.ResultsEleven randomized controlled trials involving 713 obese patients undergoing general anesthesia were selected for final meta-analysis. We noted desflurane was associated with a shorter time to eye-opening than sevoflurane (SMD: β0.86; 95% CI, β1.43 to β0.28; Pβ=β0.003). The use of desflurane with shorter time to extubation as compared with propofol (SMD: β1.13; 95% CI, β1.52 to β0.73; Pβ<β0.001) or sevoflurane (SMD: β1.19; 95% CI, β2.15 to β0.22; Pβ=β0.016), while sevoflurane was associated with longer time to extubation as compared with propofol (SMD: 1.47; 95% CI, 1.03 to 1.91; Pβ<β0.001). Desflurane were associated with shorter time to stating name as compared with propofol (SMD: β1.40; 95% CI, β2.32 to β0.48; Pβ=β0.003) or sevoflurane (SMD: β2.09; 95% CI, β3.33 to β0.85; Pβ=β0.001). In addition, desflurane was associated with a longer time for orientation to place as compared with propofol (SMD: 0.65; 95% CI, 0.22 to 1.07; Pβ=β0.003), while desflurane with shorter time for orientation to place as compared with sevoflurane (SMD: β0.88; 95% CI, β1.46 to β0.30; Pβ=β0.003).ConclusionsThe use of desflurane could provide better recovery outcomes in obese patients undergoing general anesthesia. Further large-scale trials should be comparison the long-term effectiveness of various anesthetics
VASP Activation via the GΓΕ½ΓΒ±13/RhoA/PKA Pathway Mediates Cucurbitacin-B-Induced Actin Aggregation and Cofilin-Actin Rod Formation
Cucurbitacin B (CuB), a potent antineoplastic agent of cucurbitacin triterpenoids, induces rapid disruption of actin cytoskeleton and aberrant cell cycle inhibiting carcinogenesis. However, the underlying molecular mechanism of such anticancer effects remains incompletely understood. In this study, we showed that CuB treatment rapidly induced vasodilator-stimulated phosphoprotein (VASP) phosphorylation (i.e. activation) at the Ser157 residue and generated VASP clumps which were co-localized with amorphous actin aggregates prior to the formation of highly-ordered cofilin-actin rods in melanoma cells. Knockdown of VASP or inhibition of VASP activation using PKA-specific inhibitor H89 suppressed CuB-induced VASP activation, actin aggregation and cofilin-actin rod formation. The VASP activation was mediated by cAMP-independent PKA activation as CuB decreased the levels of cAMP while MDL12330A, an inhibitor of adenylyl cyclase, had weak effect on VASP activation. Knockdown of either GΞ±13 or RhoA not only suppressed VASP activation, but also ameliorated CuB-induced actin aggregation and abrogated cofilin-actin rod formation. Collectively, our studies highlighted that the CuB-induced actin aggregation and cofilin-actin rod formation was mediated via the GΞ±13/RhoA/PKA/VASP pathway
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