排序方式: 共有41条查询结果,搜索用时 15 毫秒
31.
Shoshana Abramovich Slavica Ivelić Josip Pečarić 《Central European Journal of Mathematics》2010,8(5):937-949
We present integral versions of some recently proved results which improve the Jensen-Steffensen and related inequalities
for superquadratic functions. For superquadratic functions which are not convex we get inequalities analogous to the integral
Jensen-Steffensen inequality for convex functions. Therefore, we get refinements of all the results which use only the convexity
of these functions. One of the inequalities that we obtain for a superquadratic function φ is
$
\bar y \geqslant \phi \left( {\bar x} \right) + \frac{1}
{{\lambda \left( \beta \right) - \lambda \left( \alpha \right)}}\int_\alpha ^\beta {\phi \left( {\left| {f\left( t \right) - \bar x} \right|} \right)d\lambda \left( t \right)}
$
\bar y \geqslant \phi \left( {\bar x} \right) + \frac{1}
{{\lambda \left( \beta \right) - \lambda \left( \alpha \right)}}\int_\alpha ^\beta {\phi \left( {\left| {f\left( t \right) - \bar x} \right|} \right)d\lambda \left( t \right)}
相似文献
32.
Dawn M. Stovall Colleen Dai Shoshana Zhang Michael H. Abraham 《Physics and Chemistry of Liquids》2016,54(1):1-13
Experimental solubility, acid-dissociation constants (pKa) and activity coefficient data have been compiled from the published pharmaceutical and chemical literature for neutral organic molecules and ionic species dissolved in anhydrous 1,2-propylene glycol. The compiled experimental data were transformed into molar solubility ratios, water-to-anhydrous propylene glycol (P) and gas-to-anhydrous propylene glycol (K) using standard thermodynamic relationships. The derived Abraham model correlations described the observed solubility and partition coefficient data of neutral organic compounds and ionic species to within 0.18 log units and 0.18 log units (or less), respectively. 相似文献
33.
Nathalie Boutonnet Daniel Van Belle Shoshana J. Wodak 《Theoretical chemistry accounts》2001,106(1-2):10-21
With the aim of identifying structural changes in acetylcholinesterase, induced by ligand binding, we use a completely automatic
procedure to analyse the differences between the backbone conformation of the free enzyme and those in eight complexes of
Torpedo californica acetylcholinesterase, with various quaternary ammonium ligands, and with the protein inhibitor fasciculin. In order to discriminate
between structural changes due to ligand binding and those arising from model imprecision, we also examine protein–ligand
and protein–water contacts. Except for the peptide flip in the complex with huperzine A, the backbones of other complexes
with quaternary ammonium ligands display negligible changes relative to the free enzyme. Another exception is the complex
with the bisquaternary ammonium ligand decamethonium, where several loops display above average deformations, but only two,
those spanning residues 334–348 and residues 277–304, seem to move as a result of ligand binding. Movement of the ω loop (residues
61–95) is detected only in the complex with the protein fasciculin.
Received: 21 July 2000 / Accepted: 18 September 2000 / Published online: 28 February 2001 相似文献
34.
A general topological procedure is described that is able to detect cavities of all shapes and sizes in a system of interpenetrating spheres. The procedure is coupled to an analytic algorithm for computing surface areas and volumes, but as such, involves only logical operations and is therefore not subject to numerical imprecision. Its application to the identification of internal cavities in molecular systems is illustrated. 相似文献
35.
Sulfated polysaccharides from red microalgae have antiinflammatory properties in vitro and in vivo 总被引:5,自引:0,他引:5
The primary goal of the present research was to determine whether sulfated polysaccharides derived from red microalgae possess
anti inflammatory properties when directed against specific parameters of human skin inflammation. These unique biopolymers
were studied in both in vitro and in vivo models of skin inflammation. Human subjects were recruited to participatein a study
in which the polysaccharide material was applied topically and shown to inhibit cutaneousery thema induced by a known irritant.
Leukocyte migration from capillary blood intosites of inflammation is an essential component of the inflammatory process and
occurs in a series of steps, two of which are adhesion and chemotaxis. In vitro, the polysaccharide material primarily inhibited
the migration of polymorphonuclear leukocytes (PMNs) toward a standard chemoattractant molecule and also partially blocked
adhesion of PMNs to endothelial cells. The data obtained strongly suggest that sulfated polysaccharides derived from red microalgae
have significant beneficial potential for use in topical products. In addition, the data suggested that the anti inflammatory
mechanism for the polysaccharide was, at least in part, due to inhibition of circulating immune cell recruitment toward inflammatory
stimuli. 相似文献
36.
37.
Freeman NS Tal-Gan Y Klein S Levitzki A Gilon C 《The Journal of organic chemistry》2011,76(9):3078-3085
Aza-peptides are peptidomimetics in which one or more of the α-carbons, bearing the side-chain residues, has been replaced by a nitrogen. These peptidomimetics have been shown to be promising for the generation of drug leads and for structure-activity relationship studies. Aza-scan is the systematic replacement of amino acid residues in a given peptide with their aza counterparts. We report here an aza-scan of a potent, peptide-based PKB/Akt inhibitor, PTR6154. Procedures for microwave-assisted, Fmoc/t-Bu chemistry, solid-phase aza-peptide synthesis were developed which significantly reduce standard reaction time and are suitable for automation. Novel substituted hydrazines have been prepared for the straightforward incorporation of aza-arginine and aza-proline residues. This work will enable aza-scan to become a more common and standard method for structure-activity relationship studies of peptides. 相似文献
38.
Leung E Datti A Cossette M Goodreid J McCaw SE Mah M Nakhamchik A Ogata K El Bakkouri M Cheng YQ Wodak SJ Eger BT Pai EF Liu J Gray-Owen S Batey RA Houry WA 《Chemistry & biology》2011,18(9):1167-1178
ClpP is a cylindrical serine protease whose ability to degrade proteins is regulated by the unfoldase ATP-dependent chaperones. ClpP on its own can only degrade small peptides. Here, we used ClpP as a target in a high-throughput screen for compounds, which activate the protease and allow it to degrade larger proteins, hence, abolishing the specificity arising from the ATP-dependent chaperones. Our screen resulted in five distinct compounds, which we designate as Activators of Self-Compartmentalizing Proteases 1 to 5 (ACP1 to 5). The compounds are found to stabilize the ClpP double-ring structure. The ACP1 chemical structure was considered to have drug-like characteristics and was further optimized to give analogs with bactericidal activity. Hence, the ACPs represent classes of compounds that can activate ClpP and that can be developed as potential novel antibiotics. 相似文献
39.
The actual mechanism of cholesterol reduction by phytosterols is yet to be explored. One hypothesis states that cholesterol and phytosterols compete on the solubilization locus within gastric bile salt micelles. In this study competitive solubilization within microemulsions as vehicles for dietary intake of cholesterol and phytosterols was studied by pulse gradient spin-echo nuclear magnetic resonance. The loaded microemulsions undergo phase transitions as a function of dilution, the type of solubilized sterol, and the weight ratio of the cosolubilized sterols. Microemulsions containing 10-20 wt% of aqueous phase, show similar diffusivity of the oil and aqueous phases in all examined systems (excluding PS-loaded one) reflecting the minor influence of these solubilizates on the structure of the inner and the outer phases. The closeness of these structures enables the mobility of water molecules between them. Upon further dilution (>20 wt% aqueous phase), significant differences in decrease rate of the oil and increase of the water phases mobilities (occurring upon inversion), were detected within the studied systems. It was concluded that the solubilized sterols influence the structural transitions based on their location within the structures and their competitive solubilization. The phytosterols solubilized mostly in the continuous oil phase and between the surfactant tails. Cholesterol is solubilized in the vicinity of the surfactant headgroups and affects the surface curvature. In mixtures of cholesterol and phytosterols, structural changes are dictated mostly by the presence of the cholesterol. 相似文献
40.
In this study, an investigation was undertaken to determine whether the predictive accuracy of an indirect, multiwavelength
spectroscopic technique for rapidly determining oxygen demand (OD) values is affected by the use of unfiltered and turbid
samples, as well as by the use of absorbance values measured below 200 nm. The rapid OD technique was developed that uses
UV–Vis spectroscopy and artificial neural networks (ANNs) to indirectly determine chemical oxygen demand (COD) levels. It
was found that the most accurate results were obtained when a spectral range of 190–350 nm was provided as data input to the
ANN, and when using unfiltered samples below a turbidity range of 150 NTU. This is because high correlations of above 0.90
were obtained with the data using the standard COD method. This indicates that samples can be measured directly without the
additional need for preprocessing by filtering. Samples with turbidity values higher than 150 NTU were found to produce poor
correlations with the standard COD method, which made them unsuitable for accurate, real-time, on-line monitoring of OD levels. 相似文献
|