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101.
An atomic-scale structure of amorphous silicon, generated by reverse Monte Carlo, has been used as a starting configuration for finite temperature molecular dynamics simulations performed by an orthogonal tight binding Hamiltonian. Structural, dynamic, elastic and electronic structure properties have been investigated in the range of temperatures up to and above the melting transition. The amorphous silicon structure undergoes a melting transition at a temperature sensibly smaller than that of the crystalline structure. Above this temperature, the structure has the same properties of an under-cooled liquid and it has a metallic behavior. 相似文献
102.
We examine the conductance behavior of a cavity containing a relatively opaque transverse barrier. We show that the transmission
of this structure is strongly dependent on the longitudinal position of the barrier and, in particular, has a maximum value
when the barrier is located exactly in the middle of the cavity. In this specific condition the overall conductance is much
greater than that associated with the barrier alone. Finally we propose a physical interpretation for the obtained numerical
results. 相似文献
103.
Kuwanon‐L as a New Allosteric HIV‐1 Integrase Inhibitor: Molecular Modeling and Biological Evaluation 下载免费PDF全文
Dr. Francesca Esposito Dr. Cristina Tintori Dr. Riccardo Martini Dr. Frauke Christ Prof. Zeger Debyser Roberto Ferrarese Dr. Gianluigi Cabiddu Dr. Angela Corona Dr. Elisa Rita Ceresola Dr. Andrea Calcaterra Dr. Valentina Iovine Prof. Bruno Botta Dr. Massimo Clementi Dr. Filippo Canducci Prof. Maurizio Botta Prof. Enzo Tramontano 《Chembiochem : a European journal of chemical biology》2015,16(17):2507-2512
HIV‐1 integrase (IN) active site inhibitors are the latest class of drugs approved for HIV treatment. The selection of IN strand‐transfer drug‐resistant HIV strains in patients supports the development of new agents that are active as allosteric IN inhibitors. Here, a docking‐based virtual screening has been applied to a small library of natural ligands to identify new allosteric IN inhibitors that target the sucrose binding pocket. From theoretical studies, kuwanon‐L emerged as the most promising binder and was thus selected for biological studies. Biochemical studies showed that kuwanon‐L is able to inhibit the HIV‐1 IN catalytic activity in the absence and in the presence of LEDGF/p75 protein, the IN dimerization, and the IN/LEDGF binding. Kuwanon‐L also inhibited HIV‐1 replication in cell cultures. Overall, docking and biochemical results suggest that kuwanon‐L binds to an allosteric binding pocket and can be considered an attractive lead for the development of new allosteric IN antiviral agents. 相似文献
104.
Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2 μg/dl in children and almost 1 μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented. 相似文献
105.
HPLC is applied and assessed as an effective tool to investigate both the production of PLA by polycondensation and its corresponding degradation. A new HPLC calibration procedure, through which it is possible to fully characterize LMW PLA samples by determining the concentration of each individual oligomer, is developed. A comparison between HPLC, 1H NMR spectroscopy and non‐aqueous solution titration is also reported in order to confirm the reliability of the proposed method. Finally, the proposed analytical technique is applied to monitor the development of a polycondensation reaction performed at 150 °C and 133.3 mbar for 12 h.
106.
This review presents the state of the art regarding the improvement of scratch resistance of polymeric coatings. In particular, our attention is focused on the effect of inorganic nanometric fillers on the scratch resistance of organic coatings. Two main strategies are described for the achievement of such nanostructured hybrid organic/inorganic coatings: either a top‐down or a bottom‐up approach.
107.
Protocatechuic acid activates key components of insulin signaling pathway mimicking insulin activity 下载免费PDF全文
108.
109.
Paolo Massimo Buscema Giulia Massini Marco Fabrizi Marco Breda Francesca Della Torre 《Computational Intelligence》2018,34(1):310-344
This research has 6 fundamental aims: (i) to present a modified version of Taylor's interpolation, one that is more effective and faster than the original; (ii) outline the capability of artificial neural networks (ANNs) to perform an optimal functional approximation of the digital elevation model reconstruction from a satellite map, using a small and independent sample of Global Positioning System observations; (iii) demonstrate experimentally how ANNs outperform the traditional and most used algorithm for the height interpolation (Taylor's interpolation); (iv) introduce a new ANN, the Conic Net, able to outperform the results of the classic and more known multilayer perceptron; (v) determine that Conic Nets, even when using Taylor's modified interpolation as input features, are able to optimally approximate the heights with one order of magnitude more than the original satellite map; and (vi) make evident the possibility to interpolate the DEM heights through an ANN, which learns a data set of known points. 相似文献
110.
Yukio Kakuda Firouz Jahaniaval Massimo F. Marcone Lourdes Montevirgen Quintin Montevirgen Joselyn Umali 《Journal of the American Oil Chemists' Society》2000,77(9):991-997
The fatty acid and triacylglycerol composition of pili nut (Canarium ovatum) oil and fractions were analyzed by gas chromatography and reversed-phase high-performance liquid chromatography, respectively.
The oil obtained by solvent extraction was low in polyunsaturated fatty acids and high in saturates. The polyunsaturated fatty
acid (18∶2 and 18∶3) contents were less than 11%, whereas palmitic (16∶0) and stearic acid (18∶0) were 33.3 and 10.9%, respectively.
The saturated fatty acid level of the low-melting fraction oil was reduced from 44.4 to 35.5% and the total unsaturated fatty
acid levels were increased from 55.6 to 65% by fractional crystallization. Triacylglycerol analysis showed that the high-melting
fraction (HM) from pili nut oil consisted of POP, POS, and SOS+SSO (P=palmitic acid, O=oleic acid, and S=stearic acid) in
the proportion of 48.6, 38.8, and 8.7%, respectively. The physicochemical properties of the HM fraction were studied using
differential scanning calorimetry and pulsed nuclear magnetic resonance. The results showed that the melting range and solid
fat content of the HM fraction were very similar to those isolated from cocoa butter and olive oil. The content of POP played
an important role in determining the melting range of the HM fraction. It is suggested that this HM fraction may have applications
as a cocoa butter substitute in confectionery products. 相似文献