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101.
Electromembrane extraction (EME) is a powerful extraction and preconcentration technique for ionizable species. However, the ionic contents in the sample can influence the extraction efficiency and system stability due to electrolysis. In this work, the electromembrane extraction of chromium(VI) was developed using various levels of ionic samples. 2-Nitrophenyl octyl ether was the most suitable supported liquid membrane that delayed the electrolytic occurrence of air bubbles at the electrodes due to its high viscosity and high dielectric constant properties. The electromembrane extraction method was optimized using 5?mM NaCl (630?µS?cm?1); the applied potential was 100?V and the extraction time was 15?min. The enrichment factor of 80 was obtained over a linear working range of 10.0–80.0?µg?L?1. The method performance was tested using mineral water, drinking water, tap water, and surface water. The method recoveries based on matrix-matched calibration were 95–125% with standard deviations within 15%.  相似文献   
102.
103.
Antibiotic resistance has emerged as a major threat to global health care. This is largely due to the fact that many pathogens have developed strategies to acquire resistance to antibiotics. Metallo‐β‐lactamases (MBL) have evolved to inactivate most of the commonly used β‐lactam antibiotics. AIM‐1 is one of only a few MBLs from the B3 subgroup that is encoded on a mobile genetic element in a major human pathogen. Here, its mechanism of action was characterised with a combination of spectroscopic and kinetic techniques and compared to that of other MBLs. Unlike other MBLs it appears that AIM‐1 has two avenues available for the turnover of the substrate nitrocefin, distinguished by the identity of the rate‐limiting step. This observation may be relevant with respect to inhibitor design for this group of enzymes as it demonstrates that at least some MBLs are very flexible in terms of interactions with substrates and possibly inhibitors.  相似文献   
104.
Let ■ be the open unit disk in the complex plane ■.For α-1,let dA_α(z)=(1+α)1-|z|~2αd A(z) be the weighted Lebesgue measure on ■.For a positive function ω∈L~1(■,dA_α),the generalized weighted Bergman-Orlicz space A_ω~ψ(■,dA_α)isthe space of all analytic functions such that ||f||_ω~ψ=∫_■ψ(|f(z)|)ω(z)dA_α(z)∞,where ψ is a strictly convex Orlicz function that satisfies other technical hypotheses.Let G be a measurable subset of ■,we say G satisfies the reverse Carleson condition for A_ω~ψ(■,dA_α) if there exists a positive constant C such that ∫_Gψ(|f(z)|)ω(z)dA_α(z)≥C∫_■ψ(|f(z)|)ω(z)dA_α(z),for all f∈A_ω~ψ(■,dA_α).Let μ be a positive Borel measure,we say μ satisfies the direct Carleson condition if there exists a positive constant M such that for all f∈A_ω~ψ(■,dA_α),∫_■ψ(|f(z)|)dμ(z)≤M∫_■ψ(|f(z)|)ω(z)dA_α(z).In this paper,we study the direct and reverse Carleson condition on the generalized weighted Bergman-Orlicz space A_ω~ψ(■,dA_α).We present conditions on the set G such that the reverse Carleson condition holds.Moreover,we give a sufficient conditionfor the finite positive Borel measureμto satisfy the direct carleson condition on the generalized weighted Bergman-Orlicz spaces.  相似文献   
105.
Natural honey contains an array of glycoproteins, proteoglycans and glycopeptides. Size-exclusion chromatography fractionated Ziziphus honey proteins into five peaks with molecular masses in the range from 10 to >200 kDa. The fractionated proteins exhibited in vitro activities against Giardia lamblia with IC50 values ≤ 25 μg/mL. Results indicated that honey proteins were more active as antiprotozoal agents than metronidazole. This study indicated the potential of honey proteins and peptides as novel antigiardial agents.  相似文献   
106.
The pentacyclic triterpenoids (PTs) of plant origin are reputed to restrain prostate cancer (PCa) cell proliferation. This study aims to assess 3-epifriedelinol (EFD) isolated from aerial part of Ipomoea batatas against PCa and its potential mechanism, in vitro and in vivo. Molecular docking affirms good binding affinity of the compound with target proteins exhibiting binding energy of −7.9 Kcal/mol with BAX, −8.1 Kcal/mol (BCL-2), −1.9 Kcal/mol (NF-κB) and −8.5 Kcal/mol with P53. In the MTT assay, EFD treatment (3–50 µM) showed a significant (p < 0.05 and p < 0.01) dose and time dependent drop in the proliferative graph of DU145 and PC3, and an upsurge in apoptotic cell population. EFD displayed substantial IC50 against DU145 (32.32 ± 3.72 µM) and PC3 (35.22 ± 3.47 µM). According to Western blots, EFD administration significantly enhanced the cleavage of caspases and PARP, elevated BAX and P53 and decreased BCL-2 and NF-κB expression, thereby triggering apoptosis in PCa cells. When male Sprague Dawley rats were intoxicated with Bisphenol A (BPA), an apparent increase in prostate mass (0.478 ± 0.08 g) in comparison to control (0.385 ± 0.03 g) indicates prostatitis. Multidose treatment of EFD (10 mg/kg) significantly reduced prostate size (0.404 ± 0.05 g). EFD exhibited substantial curative potential in vivo, as hematological, hormonal and histopathological parameters have been significantly improved. Reduced peroxidation (TBARS), and suppression of inflammatory markers i.e., NO, IL-6 and TNF-α, signposts substantial antiinflammatory potential of the compound. Overall, EFD has shown better binding affinity with target molecules, acceptable ADMET profile, potent antiproliferative and apoptotic nature and significant reduction in inflamed prostate mass of rats. The present study demonstrates acceptable physicochemical and pharmacokinetic properties of the compound with excellent drugable nature, hence EFD in the form of standardized formulation can be developed as primary or adjuvant therapy against PCa and toxins-induced gonadotoxicity.  相似文献   
107.
Multivariate spectrophotometric calibration and liquid chromatographic (LC) methods were applied to the determination of 2 multicomponent mixtures containing diprophylline, guaiphenesin, methylparaben, and propylparaben (Mixture 1), or clobutinol, orciprenaline, saccharin sodium, and sodium benzoate (Mixture 2). For the multivariate spectrophotometric calibration methods, principal component regression (PCR) and partial least-squares regression (PLS-1), a calibration set of the mixtures consisting of the components of each mixture was prepared in 0.1 M HCl. Analytical figures of merit such as sensitivity, selectivity, limit of quantitation, and limit of detection were determined for both PLS-1 and PCR. The LC separation was achieved on a reversed-phase C18 analytical column by using isocratic elution with 20 mM potassium dihydrogen phosphate, pH 3.3-acetonitrile (55 + 45, v/v) as the mobile phase and UV detection at 260 and 220 nm for Mixture 1 and Mixture 2, respectively. The proposed methods were validated and successfully applied to the analysis of pharmaceutical formulations and laboratory-prepared mixtures containing the 2 multicomponent combinations.  相似文献   
108.
Single crystalline NiO nanoplatelets were successfully synthesized by new facile method at 200 °C. The morphology and microstructure were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD measurement indicated that the prepared sample had typical cubic structures. The SEM investigation confirmed that the product was of the form of nanoplatelets. These nanoplatelets have average width length 250 nm and thickness of 20 nm. The field emission measurements demonstrate that the NiO nanoplatelets show a promising field emission property. The improved field emission is attributed to the local field enhancement factor at the nanoplatelets. The results confirm the importance of the morphology of nanomaterial in field emission.  相似文献   
109.
The effects of doping with CeO2 and calcination temperature on the physicochemical properties of the NiO/Al2O3 system have been investigated using DTA, XRD, nitrogen adsorption measurements at −196°C and decomposition of H2O2 at 30–50°C. The pure and variously doped solids were subjected to heat treatment at 300, 400, 700, 900 and 1000°C. The results revealed that the specific surface areas increased with increasing calcination temperature from 300 to 400°C and with doping of the system with CeO2. The pure and variously doped solids calcined at 300 and 400°C consisted of poorly crystalline NiO dispersed on γ-Al2O3. Heating at 700°C resulted in formation of well crystalline NiO and γ-Al2O3 phases beside CeO2 for the doped solids. Crystalline NiAl2O4 phase was formed starting from 900°C. The degree of crystallinity of NiAl2O4 increased with increasing the calcination temperature from 900 to 1000°C. An opposite effect was observed upon doping with CeO2. The NiO/Al2O3 system calcined at 300 and 400°C has catalytic activity higher than individual NiO obtained at the same calcination temperatures. The catalytic activity of NiO/Al2O3 system increased, progressively, with increasing the amount of CeO2 dopant and decreased with increasing the calcination temperature.  相似文献   
110.
The global economic crisis has a significant impact on healthcare resource provision worldwide. The management of limited healthcare resources is further challenged by the high level of uncertainty in demand, which can lead to unbalanced utilization of the available resources and a potential deterioration of patient satisfaction in terms of longer waiting times and perceived reduced quality of services. Therefore, healthcare managers require timely and accurate tools to optimize resource utility in a complex and ever-changing patient care process. An interactive simulation-based decision support framework is presented in this paper for healthcare process improvement. Complexity and different levels of variability within the process are incorporated into the process modeling phase, followed by developing a simulation model to examine the impact of potential alternatives. As a performance management tool, balanced scorecard (BSC) is incorporated within the framework to support continual and sustainable improvement by using strategic-linked performance measures and actions. These actions are evaluated by the simulation model developed, whilst the trade-off between objectives, though somewhat conflicting, is analysed by a preference model. The preference model is designed in an interactive and iterative process considering decision makers preferences regarding the selected key performance indicators (KPIs). A detailed implementation of the framework is demonstrated on an emergency department (ED) of an adult teaching hospital in north Dublin, Ireland. The results show that the unblocking of ED outflows by in-patient bed management is more effective than increasing only the ED physical capacity or the ED workforce.  相似文献   
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