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Straightforward Method (straightforward + method)
Selected AbstractsChemInform Abstract: Straightforward Method for Synthesis of Highly Alkyl-Substituted Naphthacene and Pentacene Derivatives by Homologation.CHEMINFORM, Issue 16 2001Tamotsu Takahashi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Induction of apoptosis by A3 adenosine receptor agonist N6 -(3-iodobenzyl)-adenosine-5,- N -methylcarboxamide in human leukaemia cells: a possible involvement of intracellular mechanismACTA PHYSIOLOGICA, Issue 2 2010P. Mlejnek Abstract Aim:, The sensitivity of cancer cells which exhibit multi-drug resistance phenotype to A3 adenosine receptor (A3AR) agonist N6 -(3-iodobenzyl)-adenosine-5,- N -methylcarboxamide (IB-MECA) was studied. Methods:, To establish direct relationship between P-glycoprotein (P-gp, ABCB1 and MDR1) expression and IB-MECA induced cell death, a straightforward method for precise estimation of intracellular level of this A3AR agonist was developed. Results:, We subjected three human leukaemia cell lines HL-60, K562 and K562/HHT to treatment with micromolar concentrations of IB-MECA. Although all cell lines used expressed A3AR, there was a large difference in their sensitivity to IB-MECA. While HL-60 and K562 cells were almost equally sensitive, the K562/HHT cells, which exhibit a multi-drug resistance phenotype because of overexpression of P-gp, were significantly more resistant. We found that the intracellular level of IB-MECA in K562/HHT cells was approx. 10 times lower than those in HL-60 or K562 cells. Inhibitors of P-gp, including cyclosporine A (CsA) and verapamil (Vpa), increased the intracellular level of IB-MECA and reversed the resistance of K562/HHT cells to this drug. Accordingly, shRNA-mediated down-regulation of P-gp significantly increased the intracellular level of IB-MECA in K562/HHT cells which simultaneously exhibited reduced resistance to this A3AR agonist. In addition, an in vitro enzyme-based assay provided evidence that IB-MECA might serve as a substrate for P-gp. Conclusion:, Our results suggest that P-gp overexpression prevents cells from IB-MECA induced apoptosis despite the A3AR expression. Pro-apoptotic effect of IB-MECA seemed to strongly depend on its intracellular accumulation rather than on its interaction with A3AR. [source] Suzuki,Miyaura Coupling Reaction of Boronic Acids and Ethyl Glyoxylate: Synthetic Access to Mandelate DerivativesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 34 2008Irene Notar Francesco Abstract The palladium-catalyzed coupling reaction of arylboronicacids with ethyl glyoxylate provides a straightforward method for the synthesis of mandelic esters. Pd2(dba)3·CHCl3 in combination with 2-di- tert -butylphosphanylbiphenyl as the catalytic system and Cs2CO3 as the base were used. The reaction tolerates a wide range of functionalized boronicacids. Mandelic esters were isolated in good-to-excellent yields with a variety of neutral, slightly electron-rich, and slightly electron-poor substituents.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Case-only genome-wide interaction study of disease risk, prognosis and treatmentGENETIC EPIDEMIOLOGY, Issue 1 2010Brandon L. Pierce Abstract Case-control genome-wide association (GWA) studies have facilitated the identification of susceptibility loci for many complex diseases; however, these studies are often not adequately powered to detect gene-environment (G×E) and gene-gene (G×G) interactions. Case-only studies are more efficient than case-control studies for detecting interactions and require no data on control subjects. In this article, we discuss the concept and utility of the case-only genome-wide interaction (COGWI) study, in which common genetic variants, measured genome-wide, are screened for association with environmental exposures or genetic variants of interest. An observed G-E (or G-G) association, as measured by the case-only odds ratio (OR), suggests interaction, but only if the interacting factors are unassociated in the population from which the cases were drawn. The case-only OR is equivalent to the interaction risk ratio. In addition to risk-related interactions, we discuss how the COGWI design can be used to efficiently detect G×G, G×E and pharmacogenetic interactions related to disease outcomes in the context of observational clinical studies or randomized clinical trials. Such studies can be conducted using only data on individuals experiencing an outcome of interest or individuals not experiencing the outcome of interest. Sharing data among GWA and COGWI studies of disease risk and outcome can further enhance efficiency. Sample size requirements for COGWI studies, as compared to case-control GWA studies, are provided. In the current era of genome-wide analyses, the COGWI design is an efficient and straightforward method for detecting G×G, G×E and pharmacogenetic interactions related to disease risk, prognosis and treatment response. Genet. Epidemiol. 34:7,15, 2010. © 2009 Wiley-Liss, Inc. [source] Raspberry-like Gold Microspheres: Preparation and Electrochemical Characterization,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2007Z. Li Abstract A straightforward method to synthesize quasi-monodisperse gold microspheres from a commercial gold plating solution is reported. The size and the surface roughness of the obtained particles can easily be tuned. In particular, raspberry-like particles with a high active surface area are obtained. The microspheres are assembled on indium tin oxide (ITO) electrodes using the layer-by-layer technique and the overall electroactive surface area is increased, as characterized by cyclic voltammetry. The as-prepared products were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), cyclic voltammetry, and light microscopy. [source] Controlling the Edge Length of Gold Nanoprisms via a Seed-Mediated Approach,ADVANCED FUNCTIONAL MATERIALS, Issue 9 2006E. Millstone Abstract A straightforward method is investigated for controlling and reinitiating the growth of single-crystalline Au nanoprisms. This work is based on seeding methodology, and depends on the slow reduction of metal ions onto the surface of a growing nanoprism. In this manner, we can tailor the edge length of Au nanoprisms between 100 and 300,nm without changing their thickness or crystallinity. Each nanoprism size has been characterized by UV-vis-NIR (NIR: near-IR) spectroscopy, transmission electron microscopy (TEM) techniques, and statistical analysis. Based on this work and existing silver halide crystal-growth theories, a preliminary mechanism is proposed which comments on the interplay between crystal growth and surface chemistry that ultimately dictates the morphology of the resulting nanostructure. [source] Accounting for Interference, Scattering, and Electrode Absorption to Make Accurate Internal Quantum Efficiency Measurements in Organic and Other Thin Solar CellsADVANCED MATERIALS, Issue 30 2010George F. Burkhard Accurately measuring internal quantum efficiency requires knowledge of absorption in the active layer of a solar cell. The experimentally accessible total absorption includes significant contributions from the electrodes and other non-active layers. We suggest a straightforward method for calculating the active layer contribution that minimizes error by subtracting optically-modeled electrode absorption from experimentally measured total absorption. [source] Multi-variable parameter estimation to increase confidence in hydrological modellingHYDROLOGICAL PROCESSES, Issue 2 2002Sten Bergström Abstract The expanding use and increased complexity of hydrological runoff models has given rise to a concern about overparameterization and risks for compensating errors. One proposed way out is the calibration and validation against additional observations, such as snow, soil moisture, groundwater or water quality. A general problem, however, when calibrating the model against more than one variable is the strategy for parameter estimation. The most straightforward method is to calibrate the model components sequentially. Recent results show that in this way the model may be locked up in a parameter setting, which is good enough for one variable but excludes proper simulation of other variables. This is particularly the case for water quality modelling, where a small compromise in terms of runoff simulation may lead to dramatically better simulations of water quality. This calls for an integrated model calibration procedure with a criterion that integrates more aspects on model performance than just river runoff. The use of multi-variable parameter estimation and internal control of the HBV hydrological model is discussed and highlighted by two case studies. The first example is from a forested basin in northern Sweden and the second one is from an agricultural basin in the south of the country. A new calibration strategy, which is integrated rather than sequential, is proposed and tested. It is concluded that comparison of model results with more measurements than only runoff can lead to increased confidence in the physical relevance of the model, and that the new calibration strategy can be useful for further model development. Copyright © 2002 John Wiley & Sons, Ltd. [source] PEGylated Calcium Phosphate Nanocomposites as Smart Environment-Sensitive Carriers for siRNA DeliveryADVANCED MATERIALS, Issue 34 2009Mingzhen Zhang A novel inorganic,organic hybrid nanocomposite is formed in situ using a simple and straightforward method. Conjugate of short interfering RNA (siRNA) duplex with poly(ethylene glycol) via a disulfide linkage (PEG,SS,siRNA) is demonstrated to regulate the crystal growth of calcium phosphate (CaP), yielding a monodispersed nanocomposite. The resultant nanocomposite can be utilized as nanocarriers for siRNA delivery. [source] Modeling solvent evaporation during the manufacture of controlled drug-release coatings and the impact on release kinetics,,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Chang-Soo Kim Abstract To improve functionality and performance, controlled drug-release coatings comprised of drug and polymer are integrated with traditional medical devices, e.g., drug eluting stents. Depending on manufacturing conditions, these coatings can exhibit complex microstructures. Previously, a thermodynamically consistent model was developed for microstructure evolution in these systems to establish relationships between process variables, microstructure, and the subsequent release kinetics. Calculations based on the model were, in general, consistent with experimental findings. However, because of assumptions regarding the evaporation of solvent during fabrication, the model was unable to capture variations through the coating thickness that are observed experimentally. Here, a straightforward method is introduced to incorporate solvent evaporation explicitly into the model. Calculations are used to probe the impact of solvent evaporation rate and drug loading on the microstructure that forms during manufacturing and subsequent drug release kinetics. The predicted structures and release kinetics are found to be consistent with experimental observations. Further, the calculations demonstrate that solvent evaporation rate can be as critical to device performance as the amount of drug within the coating. For example, changes of a factor of five in the amount of drug released were observed by modifying the rate of solvent evaporation during manufacturing. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] A simple method for SEM examination of sectioned diatom frustulesJOURNAL OF MICROSCOPY, Issue 1 2001SHORT TECHNICAL NOTE We describe an innovative yet straightforward method to obtain high quality thin sections of diatom exoskeletons for observation by scanning electron microscopy (SEM). The use of this new technique allows for clear observations of some ultrastructural valve features, including the raphe, which are generally difficult to observe and describe accurately using transmission electron microscopy analysis of thin sections or SEM of randomly fractured diatom valves. In addition, because this method involves the complete removal of the organic content of the diatom cells, resulting in clean and mostly undisturbed skeletal thin cross-sections, even the intact valvar structures of weak girdle bands can be studied. [source] RNA interference in pain researchJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Thomas Röhl Abstract Within the course of only the last few years, RNA interference (RNAi) has been established as a standard technology for investigation of protein function and target validation. The present review summarizes recent progress made in the application of RNAi in neurosciences with special emphasis on pain research. RNAi is a straightforward method to generate loss-of-function phenotypes for any gene of interest. In mammals, silencing is induced by small interfering RNAs (siRNAs), which have been shown to surpass traditional antisense molecules. Due to its high specificity, RNAi has the potential for subtype selective silencing of even closely related genes. One of the major challenges for in vivo investigations of RNAi remains efficient delivery of siRNA molecules to the relevant tissues and cells, particularly to the central nervous system. Various examples will be given to demonstrate that intrathecal application of siRNAs is a suitable approach to analyse the function of receptors or other proteins that are hypothesized to play an important role in pain signalling. Intensive efforts are currently ongoing to solve remaining problems such as the risk of off-target effects, the stability of siRNA molecules and their efficient delivery to the CNS. RNAi has thus demonstrated that it is an extremely valuable tool for the development of new analgesic drugs. [source] A new approach to automated first-order multiplet analysisMAGNETIC RESONANCE IN CHEMISTRY, Issue 5 2002Sergey Golotvin Abstract The dependence of the values of NMR spin,spin coupling constants on molecular conformation can be a valuable tool in the structure determination process. The continuing increase in the resonance frequency of modern NMR spectrometers allows an increasing number of resonances to be examined using first-order multiplet analysis. While this can easily be done for the simplest patterns (doublets, triplets, quartets), more complex patterns can be extremely difficult to analyze. The task of deducing the coupling constant values from a multiplet is the reverse process of generating a conventional splitting tree from a single line (chemical shift) by sequential branching using a given set of coupling constants. We present a simple, straightforward method of deducing coupling constant values from first-order multiplets based on a general inverted splitting tree algorithm but also including a peak intensity normalization procedure that utilizes multiplet symmetry and generates a set of possible first-order intensity distribution patterns. When combined with an inverted splitting tree algorithm, it is possible to find an intensity pattern that allows the deduction of a proper set of coupling constants. Copyright © 2002 John Wiley & Sons, Ltd. [source] Cysteine-capped ZnSe quantum dots as affinity and accelerating probes for microwave enzymatic digestion of proteins via direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2009Lokesh A. Shastri Fluorescent semiconductor quantum dots (QDs) exhibit great potential and capability for many biological and biochemical applications. We report a simple strategy for the synthesis of aqueous stable ZnSe QDs by using cysteine as the capping agent (ZnSe-Cys QDs). The ZnSe QDs can act as affinity probes to enrich peptides and proteins via direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) analysis. This nanoprobe could significantly enhance protein signals (insulin, ubiquitin, cytochrome c, myoglobin and lysozyme) in MALDI-TOFMS by 2.5,12 times compared with the traditional method. Additionally, the ZnSe-Cys QDs can be applied as heat absorbers (as accelerating probes) to speed up microwave-assisted enzymatic digestion reactions and also as affinity probes to enrich lysozyme-digested products in MALDI-TOFMS. Furthermore, after the enrichment experiments, the solutions of ZnSe-Cys QDs mixed with proteins can be directly deposited onto the MALDI plates for rapid analysis. This approach shows a simple, rapid, efficient and straightforward method for direct analysis of proteins or peptides by MALDI-TOFMS without the requirement for further time-consuming separation processes, tedious washing steps or laborious purification procedures. The present study has demonstrated that ZnSe-Cys QDs are reliable and potential materials for rapid, selective separation and enrichment of proteins as well as accelerating probes for microwave-digested reactions for proteins than the regular MALDI-MS tools. Additionally, we also believe that this work may also inspire investigations for applications of QDs in the field of MALDI-MS for proteomics. Copyright © 2009 John Wiley & Sons, Ltd. [source] Semi-automatic tuning of PID gains for atomic force microscopesASIAN JOURNAL OF CONTROL, Issue 2 2009Daniel Y. Abramovitch Abstract The control of a typical commercial Atomic Force Microscope (AFM) is through some variant on a Proportional, Integral, Derivative (PID) controller. Typically, the gains are hand tuned so as to keep the bandwidth of the system far below the first resonant frequency of the actuator. This paper shows a straightforward method of selecting PID gains from the actuator model so as to allow considerably higher bandwidths. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] High-performance liquid chromatographic method for simple and rapid determination of linezolid in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 8 2006Lauren M. Boak Abstract A simple high-performance liquid chromatographic (HPLC) method was developed and validated for rapid quantification of linezolid in human plasma. Protein precipitation using a mixture of 5% trichloroacetic acid and methanol (3:1, v/v) provided a straightforward method of sample preparation and the internal standard eperezolid was employed. A concentration range from 0.20 to 40.0 mg/L was utilized to construct calibration curves, and analysis of low- (0.40 mg/L), medium- (7.50 mg/L) and high-quality (25.0 mg/L) control samples revealed excellent reproducibility (,3.88%) and accuracy (,4.20%). The recovery of both linezolid and eperezolid was approximately 100%. No interference was observed at the retention times of linezolid and eperezolid from blank plasma or eight commonly used antibiotics. Tests confirmed the stability of linezolid in plasma during three freeze,thaw cycles, on the bench during 24 h and during long-term storage of frozen plasma for up to 12 weeks; in extracts it was stable in the HPLC autosampler over 12 h. Overall, this assay offers a highly simplistic approach to quantifying linezolid in plasma, and would be well suited to clinical pharmacokinetic, pharmacodynamic and toxicodynamic analyses. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||