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71.
An HPLC method developed to detect in a single run both atenolol and chlorthalidone, extracted from plasma, using two detectors (UV for chlorthalidone and fluorometric for atenolol) connected in series, is described. The drugs were separated on an ODS column at room temperature using a 0.05 M sodium dodecyl sulphate in phosphate buffer (pH 5.8)-n-propanol (95:5, v/v) solution, delivered at a flow-rate of 1.3 ml/min. Having ascertained the sensitivity (10 ng/ml of both drugs) and the intra-day reproducibility (pre-study validation), the reliability of the method was verified by inter-day assays (within-study validation) carried out during the analysis of plasma samples collected from healthy volunteers after single-dose treatment with atenolol+chlorthalidone tablets (pharmaceutical preparations containing 100+25 mg and 50+12.5 mg of the two drugs, respectively).  相似文献   
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73.
The ability of exogenous lysophosphatidylcholine to produce electrophysiological derangements and cardiac arrhythmias in the heart has been documented. The action of lysophosphatidylcholine is thought to be mediated via its association with the membrane. The present study examined the nature of the association of lysophosphatidylcholine with isolated rat myocyte membrane. The association was studied by incubating myocytes in a lysophosphatidylcholine-containing medium. The association of lysophosphatidylcholine with the myocyte sarcolemma was not affected by palmitic acid and glycerophosphocholine but was reduced by platelet-activating factor (PAF). The addition of albumin (5 mg/mL) at the end of the incubation period effectively removed the lysophosphatidylcholine from the myocytes. Our results suggest that most of the lysophosphatidylcholine in isolated myocytes was associated preferentially with the outer leaflet of the myocyte sarcolemma. This type of association might be responsible for the lysophosphatidylcholine-induced electrophysiological alterations in the heart.  相似文献   
74.
A very simple and rapid method for synthesizing LiFePO4-C composite has been developed by vibrant type ball-milling for 30 min and microwave heating for 2–4 min. X-ray diffraction and Mössbauer spectroscopy verify that well-crystallized LiFePO4 without Fe3+ impurities is obtained. From laser particle size analysis and transmission electron microscopy, it is confirmed that a LiFePO4-C composite with fine and uniform particle size (mean particle size ≤0.640 μm, D75 in volume distribution ≤0.592 μm) and with extremely uniform carbon distribution is prepared by vibrant type ball-milling and microwave heating. The LiFePO4-C delivers a high initial discharge capacity of 161 mAh g−1 at C/10 and shows very stable cycling behaviour.  相似文献   
75.
This study investigated the photocatalytic behavior of the coupling of TiO2 with phosphorescent materials. A TiO2 thin film was deposited on CaAl2O4:Eu2+,Nd3+ phosphor particles by using atomic layer deposition (ALD), and its photocatalytic reaction was investigated by the photobleaching of an aqueous solution of methylene-blue (MB) under visible light irradiation. To clarify the mechanism of the TiO2-phosphorescent materials, two different samples of TiO2-coated phosphor and TiO2–Al2O3-coated phosphor particles were prepared. The photocatalytic mechanisms of the ALD TiO2-coated phosphor powders were different from those of the pure TiO2 and TiO2–Al2O3-coated phosphor. The absorbance in a solution of the ALD TiO2-coated phosphor decreased much faster than that of pure TiO2 under visible irradiation. In addition, the ALD TiO2-coated phosphor showed moderately higher photocatalytic degradation of MB solution than the TiO2–Al2O3-coated phosphor did. The TiO2-coated phosphorescent materials were characterized by transmission electron microscopy (TEM), Auger electron spectroscopy (AES) and X-ray photon spectroscopy (XPS).  相似文献   
76.
In the present work, both experimental and numerical simulation methods are used to investigate the characteristics of welding distortion and residual stress distribution. A 3D thermo-mechanical Finite Element Analysis (FEA) method is used to predict the welding distortion and residual stress of cylinder-shaped multi-pass layer weldments. Each weld pass is performed using a quarter-circle balanced welding procedure. To investigate the influence of deposition sequence and welding heat input on the welding distortion and residual stress, a continuous welding procedure is also calculated. The corresponding FEA models considered a moving heat source, the deposition sequence, and temperature-dependent thermal and mechanical properties. The results predicted by 3D FEA model are generally in good agreement with the measurements. Finally, the numerical and experimental results suggest that both deposition sequence and heat input affect welding distortion and residual stress distribution. Furthermore, the 3D thermal-mechanical FEA method can predict cylinder-type welding distortion.  相似文献   
77.
It is widely accepted that surface enhanced Raman scattering (SERS) enhancement results from a combination of electromagnetic mechanisms (EM) and chemical mechanisms (CM). Recently, the nanoparticle‐film gap (NFG) system was studied due to its strong local enhancement field. However, there are still some technical limitations in establishing effective and simple ways for reliable and precise control of sub‐nanospacer. In addition, works on designing the nanospacer in NFG system for efficient interaction with target molecules for further improving SERS signals are rather limited. Here, a novel NFG system is proposed by introducing ultrathin monolayer graphene as well‐defined sub‐nanospacer between Ag NPs and Ag film (named G(graphene)‐NFG system). The new G–NFG system offers tremendous near‐field enhancement with one of the highest enhancement ratio of 1700 reported to date. These results show that the single‐layer graphene as a sub‐nanospacer renders the proposed G–NFG system with particularly strong EM enhancement (due to multiple couplings including the NP–NP couplings and NP‐film couplings) and additional CM enhancement in detecting some π‐conjugated molecules to function as a powerful tool in analytical science and the related fields.  相似文献   
78.
Understanding the contexts of knowledge is necessary to manage knowledge processes successfully. The goal of this paper is to provide a theoretical framework for understanding and utilizing knowledge that is embedded in contexts, focusing on the relationship between time and knowledge processes. This paper integrates the time lens and the literature on the knowledge based view to develop four different time contexts that can enable different organizational knowledge processes. Propositions on how to utilize time to create enabling contexts for organizational knowledge creation and innovation are developed. Suggested intervention strategies help to create contexts for knowledge creation and exploitation.  相似文献   
79.
In this paper, we first introduce a straightforward asynchronous shift register design implemented by differential cascode voltage switch logic and micropipeline. The corresponding latency defect between data readout is then described. To solve this problem, we propose a new architecture for the design. Finally, a basic building block with respect to our architecture is proposed.  相似文献   
80.
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