Home  About us  Contact
 

Highly Selective (highly + selective)

Distribution by Scientific Domains
Chemistry61%
Medical Sciences19%
Polymers and Materials Science11%
2 Other Domains9%

Terms modified by Highly Selective

  • highly selective inhibitor
    		•
  • highly selective method
    		•

    Selected Abstracts

    Cu(II)-Azabis(oxazoline)-Complexes Immobilized on Superparamagnetic Magnetite@Silica-Nanoparticles: A Highly Selective and Recyclable Catalyst for the Kinetic Resolution of 1,2-Diols

    ADVANCED FUNCTIONAL MATERIALS, Issue 13 2009
    Alexander Schätz
    Abstract Two different types of azide functionalized magnetite@silica nanoparticles are synthesized, which are ideally suited as inexpensive supports for catalysts and reagents as demonstrated with the grafting of copper(II)-azabis(oxazoline) complexes via a copper(I) catalyzed azide/alkyne cycloaddition (CuAAC) reaction. The potential of the immobilized complexes as catalysts is tested in the desymmetrization of racemic 1,2-diols through asymmetric benzoylation. Compared to azabis(oxazolines) "clicked" to common polymeric supports such as MeOPEG or Merrifield resin, Fe3O4@SiO2 proves to be superior with respect to activity and selectivity, as exemplified by employing the catalysts in up to five runs with consistent high activity and selectivity. Recycling of the catalysts is achieved quantitatively by magnetic decantation. [source]

    Crosslinked Bicontinuous Cubic Lyotropic Liquid-Crystal/Butyl-Rubber Composites: Highly Selective, Breathable Barrier Materials for Chemical Agent Protection,

    ADVANCED MATERIALS, Issue 24 2006
    X. Lu
    A breathable material that can act as a barrier to chemical agents is presented. The material is composed of butyl rubber and a crosslinkable lyotropic liquid crystal. Under the right synthesis conditions, a cubic phase with the desired selectivity properties results (see figure). The material is highly permeable to water vapor, but strongly impermeable to a mustard gas simulant. Application of the material for effective personal protection against such chemical agents is envisaged. [source]

    A Highly Selective, Polymer-Supported Organocatalyst for Michael Additions with Enzyme-Like Behavior

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009
    Esther Alza
    Abstract A polymer-supported ,,,-diarylprolinol silyl ether displays catalytic activity and enantioselectivity comparable to the best homogeneous catalysts in the Michael addition of aldehydes to nitroolefins. Above all, the combination of polymer backbone, triazole linker, and catalytic unit confers to it an unprecedented substrate selectivity in favor of linear, short-chain aldehydes. [source]

    Treatment of Perchlorate-Contaminated Groundwater Using Highly Selective, Regenerable Ion-Exchange Technology: A Pilot-Scale Demonstration

    REMEDIATION, Issue 2 2002
    Baohua Gu
    Treatment of perchlorate-contaminated groundwater using highly selective, regenerable ion-exchange technology has been recently demonstrated at Edwards Air Force Base, California. At an influent concentration of about 450 ,g/l ClO4,, the bifunctional anion-exchange resin bed treated approximately 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO4, occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO4,. The spent resin bed was successfully regenerated using the FeCl3,HCl regeneration technique recently developed at the Oak Ridge National Laboratory, and nearly 100 percent of sorbed ClO4, was displaced or recovered after elution with as little as about two bed volumes of the regenerant solution. In addition, a new methodology was developed to completely destroy ClO4, in the FeCl3,HCl solution so that the disposal of perchlorate-containing hazardous wastes could be eliminated. It is therefore anticipated that these treatment and regeneration technologies may offer an efficient and cost-effective means to remove ClO4, from contaminated groundwater with significantly reduced generation of waste requiring disposal. © 2002 Wiley Periodicals, Inc. [source]

    ChemInform Abstract: A Highly Selective, Polymer-Supported Organocatalyst for Michael Additions with Enzyme-Like Behavior.

    CHEMINFORM, Issue 18 2010
    Esther Alza
    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]

    WO3 Nanoparticles on MCM-48 as a Highly Selective and Versatile Heterogeneous Catalyst for the Oxidation of Olefins, Sulfides, and Cyclic Ketones.

    CHEMINFORM, Issue 10 2006
    Dong Hyun Koo
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    Stereoselective Synthesis of (2S,3S,4R,5S)-5-Methylpyrrolidine-3,4-diol Derivatives that Are Highly Selective ,-L-Fucosidase Inhibitors.

    CHEMINFORM, Issue 8 2006
    Antonio J. Moreno-Vargas
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF. [source]

    ChemInform Abstract: Highly Selective and Facile Diels,Alder Reactions of Masked o-Benzoquinones with Pyrroles.

    CHEMINFORM, Issue 44 2001
    Ming-Fang Hsieh
    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]

    ChemInform Abstract: Highly Selective 1,3-Dipolar Cycloaddition of a Cyclic Azomethine Ylide to Ethyltrifluorocrotonates.

    CHEMINFORM, Issue 23 2001
    Jean-Pierre Begue
    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]

    Extracting metabolite ions out of a matrix background by combined mass defect, neutral loss and isotope filtration

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 2 2009
    Filip Cuyckens
    Mass defect, neutral loss and isotope filtration techniques were applied to electrospray ionization mass spectrometry (ESI-MS) data obtained for in vivo and in vitro samples of drug metabolism studies. A combination of these post-acquisition processing techniques was shown to be more powerful than the use of one of these tools alone for the detection in complex matrices of metabolites of candidate drugs with a characteristic isotope pattern (e.g. containing bromine, chlorine, or a high proportion of radiolabeled drug (12C/14C)) or characteristic neutral losses. In combination with ,all-in-one' data acquisition this methodology is able to perform software-driven constant neutral loss scanning for an unlimited number of mass differences at any time after analysis. Highly selective MS chromatograms were obtained with excellent correlation with their corresponding radiochromatograms. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Effect of Bisoprolol on Right Ventricular Function and Brain Natriuretic Peptide in Patients With Heart Failure

    CONGESTIVE HEART FAILURE, Issue 3 2004
    Luís Beck-da-Silva MD
    Beta-blocker use improves left ventricular ejection fraction (LVEF) in patients with heart failure. A similar effect of , blockers on right ventricular function has been proposed, although the effect of bisoprolol, a highly selective ,-1 blocker, on right ventricular function has not been assessed. This study investigated the short-term effect of bisoprolol on right ventricular function in chronic heart failure patients. A cohort of 30 heart failure patients who were not taking , blockers at baseline was studied prospectively. Right ventricular ejection fraction (RVEF) and LVEF were measured at both baseline and 4 months by radionuclide angiography. Bisoprolol was up-titrated during four monthly visits by a preestablished protocol to a target dose of 10 mg/d. The dose of vasodilators was not changed. Quality of life and brain natriuretic peptide level were assessed. Mean age was 62.7±14.3 years. Baseline RVEF was 30.7%±6.3% and baseline LVEF was 21.7%±9.4%. Mean bisoprolol dose reached was 5.3±3.9 mg daily. At 4 months, RVEF significantly increased by 7.1 % (95% confidence interval, 3.9,10.2; p=0.0001) and LVEF also increased significantly by 7.9% (95% confidence interval, 4.0%,11.9%p=0.0003). Quality-of-life score improved from 42.8 to 30.8 (p=0.047). No correlation was found between brain natriuretic peptide levels and RVEF. Bisoprolol treatment for 4 months resulted in a significant improvement of RVEF, which paralleled the improvement of LVEF. [source]

    A Concise Total Synthesis of (+)-Heliotridine

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2003
    Federica Pisaneschi
    Abstract A practical synthesis of the necine base (+)-heliotridine (1) is reported here. The present total synthesis is based on the highly selective 1,3-dipolar cycloaddition of (S)-3- tert -butoxypyrroline N -oxide (2) to the commercially available ethyl 4-bromocrotonate, followed by a suitable elaboration of the adduct. The synthesis gives a 17% overall yield from nitrone 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Personality traits and academic examination performance

    EUROPEAN JOURNAL OF PERSONALITY, Issue 3 2003
    Tomas Chamorro-Premuzic
    British university students (N,=,247) completed the NEO-PI-R (Costa & McCrae, 1992) personality inventory at the beginning of their course and took several written examinations throughout their three-year degree. Personality super-traits (especially Conscientiousness positively, and Extraversion and Neuroticism negatively) were significantly correlated with examination grades and were found to account for around 15% of the variance. Primary traits were also examined and results showed significant correlations between a small number of these traits (notably dutifulness and achievement striving positively, and anxiety and activity negatively) and academic achievement. Furthermore, selected primary personality traits (i.e. achievement striving, self-discipline, and activity) were found to explain almost 30% of the variance in academic examination performance. It is argued that personality inventory results may represent an important contribution to the prediction of academic success and failure in university (particularly in highly selective and competitive settings). Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Palladium-Catalyzed Transformation of Renewable Oils into Diesel Components

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010
    Junxing Han
    Abstract A size-controlled palladium nanoparticle catalyst prepared by adsorption of colloidal palladium nanoparticles on barium sulfate is efficient and highly selective in transforming vegetable oils into diesel-like fuel. Preliminary kinetic investigations using model compounds indicated that decarboxylation of aliphatic esters on palladium in a hydrogen-rich atmosphere showed a zero-order rate. Hydrogen temperature-programmed desorption measurements revealed that the high-temperature desorption of hydrogen species might be the rate-determining step. [source]

    Copper-Catalyzed One-Pot Synthesis of 2-Alkylidene-1,2,3,4- tetrahydropyrimidines

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
    Wei Lu
    Abstract A one-pot synthesis of N -sulfonyl-2-alkylidene-1,2,3,4-tetrahydropyrimidines via a highly selective and copper-catalyzed multicomponent reaction of sulfonyl azides, terminal alkynes and ,,,-unsaturated imines has been developed. The ,,,-unsaturated imine substrates could be generated from amines and ,,,-unsaturated aldehydes in a one-pot process. The procedure is concise, general and efficient. [source]

    Preparation of ethylene/1-octene copolymers from ethylene stock with tandem catalytic system

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008
    Tao Jiang
    Abstract Tandem catalysis offers a novel synthetic route to the production of linear low-density polyethylene. This article reports the use of homogeneous tandem catalytic systems for the synthesis of ethylene/1-octene copolymers from ethylene stock as the sole monomer. The reported catalytic systems involving a highly selective, bis(diphenylphosphino)cyclohexylamine/Cr(acac)3/methylaluminoxane (MAO) catalytic systems for the synthesis of 1-hexene and 1-octene, and a copolymerization metallocene catalyst, rac -Et(Ind)2ZrCl2/MAO for the synthesis of ethylene/1-octene copolymer. Analysis by means of DSC, GPC, and 13C-NMR suggests that copolymers of 1-hexene and ethylene and copolymers of 1-octene and ethylene are produced with significant selectivity towards 1-hexene and 1-octene as comonomers incorporated into the polymer backbone respectively. We have demonstrated that, by the simple manipulation of the catalyst molar ratio and polymerization conditions, a series of branched polyethylenes with melting temperatures of 101.1,134.1°C and density of 0.922,0.950 g cm,3 can be efficiently produced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

    Effect of dexmedetomidine on the characteristics of bupivacaine in a caudal block in pediatrics

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2009
    I. SAADAWY
    Background: Dexmedetomidine (DEX) is a highly selective ,2 -adrenoceptor agonist that has been used increasingly in children. However, the effect of caudal DEX has not been evaluated before in children. This prospective randomized double-blinded study was designed to evaluate the analgesic efficacy of caudal DEX with bupivacaine in providing pain relief over a 24-h period. Methods: Sixty children (ASA status I) aged 1,6 years undergoing unilateral inguinal hernia repair/orchidopexy were allocated randomly to two groups (n=30 each). Group B received a caudal injection of bupivacaine 2.5 mg/ml, 1 ml/kg; Group BD received the same dose of bupivacaine mixed with DEX 1 ,g/kg during sevoflurane anesthesia. Processed electroencephalogram (bispectral index score), heart rate, blood pressure, pulse oximetry and end-tidal sevoflurane were recorded every 5 min. The characteristics of emergence, objective pain score, sedation score and quality of sleep were recorded post-operatively. Duration of analgesia and requirement for additional analgesics were noted. Results: The end-tidal sevoflurane concentration and the incidence of agitation were significantly lower in the BD group (P<0.05). The duration of analgesia was significantly longer (P<0.001) and the total consumption of rescue analgesic was significantly lower in Group BD compared with Group B (P<0.01). There was no statistically significant difference in hemodynamics between both groups. However, group BD had better quality of sleep and a prolonged duration of sedation (P<0.05). Conclusion: Caudal DEX seems to be a promising adjunct to provide excellent analgesia without side effects over a 24-h period. It has the advantage of keeping the patients calm for a prolonged time. Implications statement: Caudally administered DEX (1 ,g/kg), combined with bupivacaine, was associated with an extended duration of post-operative pain relief. [source]

    Highly sensitive and accurate profiling of carotenoids by supercritical fluid chromatography coupled with mass spectrometry

    JOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2009
    Atsuki Matsubara
    Abstract We attempted to establish a high-speed and high-resolution profiling method for a carotenoid mixture as a highly selective and highly sensitive detection method; the analysis was carried out by supercritical fluid chromatography (SFC) coupled with mass spectrometry (MS). When an octadecyl-bonded silica (ODS) particle-packed column was used for separation, seven carotenoids including structural isomers were successfully separated within 15 min. This result indicated not only improved separation but also improved throughput compared to the separation and throughput in RP-HPLC. The use of a monolithic ODS column resulted in additional improvement in both the resolution and the throughput; the analysis time was reduced to 4 min by increasing the flow rate. Furthermore, carotenoids in biological samples containing the complex matrices were separated effectively by using several monolithic columns whose back pressure was very low. The mass spectrometer allowed us to perform a more sensitive analysis than UV detection; the detection limit of each carotenoid was 50 pg or below. This is the first report of carotenoid analysis carried out by SFC-MS. The profiling method developed in this study will be a powerful tool for carrying out accurate profiling of biological samples. [source]

    Conversion to Silodosin in Men on Conventional ,1 -Blockers for Symptomatic Benign Prostatic Hyperplasia

    LUTS, Issue 1 2010
    Masahiko TANAKA
    Objectives:,1 -blockers have commonly been used as first-line medical therapy for symptomatic benign prostatic hyperplasia (BPH). Recently, a highly selective ,1A -adrenoceptor antagonist, silodosin, was developed in Japan. We examined the efficacy and safety of conversion from conventional ,1 -blockers to silodosin in men with BPH. Methods: Conversion to silodosin was proposed to consecutive patients on conventional ,1 -blockers for symptomatic BPH for at least 6 months. The effects of conversion were examined by the International Prostate Symptom Score, quality of life index, overactive bladder symptom score, peak flow rate, residual urine volume, and adverse events at 12 weeks. The efficacy of silodosin was also evaluated by patients' impression. Results: Eighty-one men underwent conversion, for the most part because of dissatisfaction with the efficacy of their current treatment in improving nocturia or weak stream. The International Prostate Symptom Score total score significantly improved from 12.7 ± 5.9 at baseline to 10.6 ± 5.4 at 4 weeks (P < 0.001) and 10.9 ± 5.8 at 12 weeks (P < 0.01). The progress was mostly due to improvement in voiding symptoms, although reduction of storage symptoms was also significant. The quality of life index also significantly decreased with conversion to silodosin. Efficacy as judged by patients' impression was 76% (37/49) at 12 weeks of treatment. None of the overactive bladder symptom score, peak flow rate, and residual urine volume exhibited significant change. No serious adverse events were observed during the study period. Conclusion: Conversion to silodosin may be beneficial in men who are dissatisfied with conventional ,1 -blockers for BPH, and be particularly useful in improving voiding symptoms. [source]

    Adrenaline hypothesis: effect of formoterol on noradrenaline release

    AUTONOMIC & AUTACOID PHARMACOLOGY, Issue 5 2001
    E. Maignan
    Summary 1 Originally, the so-called `adrenaline hypothesis' related the release of noradrenaline (NA) to stimulation of presynaptic ,2 -receptors in nerve endings; now it confers a possible role to adrenaline taken up then released by nerves endings. It represents a potentially useful therapeutic pathway. The present study aims to investigate the effects of formoterol, a highly selective ,2 -adrenoceptor agonist. 2 It was carried out in freely moving rats, the isotope dilution technique being used to measure the NA spill over rate (NA-SOR) and metabolic clearance rate (MCR). 3 A series of three results are reported. (a) When compared with adrenaline on equimolar basis, formoterol (2.3 ,g kg,1 min,1) increased NA-SOR while mean arterial blood pressure was decreased and heart rate increased. Thus, it was difficult to separate a direct presynaptic effect from indirect baroreflex-dependent activation of the sympathetic system. (b) When formoterol was infused at 1 ng kg,1 min,1, a dose empirically defined to induce no haemodynamic effect, NA-SOR was significantly increased, while NA-MCR remained unchanged. (c) The NA-SOR response to formoterol was not amplified by the presynaptic ,2 -adrenoceptor blocker, yohimbine, in contrast to the NA-SOR response to adrenaline. 4 In conclusion, formoterol, a ,2 -adrenoceptor agonist, is shown to increase the release and plasma concentration of NA while its clearance was not changed. [source]

    Development and validation of an on-line two-dimensional reversed-phase liquid chromatography,tandem mass spectrometry method for the simultaneous determination of prostaglandins E2 and F2, and 13,14-dihydro-15-keto prostaglandin F2, levels in human plasma

    BIOMEDICAL CHROMATOGRAPHY, Issue 3 2009
    Junji Komaba
    Abstract We developed and validated an on-line reverse-phase two-dimensional LC/MS/MS (2D-LC/MS/MS) system for simultaneous determination of the levels of prostaglandin (PG) E2 as well as PGF2, and its metabolite 13,14-dihydro-15-keto PGF2, (F2, -M) in human plasma. Analytes were extracted by a three-step solid-phase extraction. Samples were then analyzed by on-line 2D-LC/MS/MS with electrospray ionization in negative mode. The 2D-LC system is composed of two reverse-phase analytical columns with a trapping column linking the two analytical columns. While an acidic buffer was used for both separation dimensions, differing organic solvents were employed for each dimension: methanol for the first and acetonitrile for the second to increase resolving power. The 2D-LC/MS/MS method was highly selective and sensitive with a significantly lower limit of quantitation (0.5 pg/mL for PGE2 and 2.5 pg/mL for PGF2, and F2, -M, respectively). Linearity of the 2D-LC/MS/MS system was demonstrated for the calibration ranges of 0.5,50 pg/mL for PGE2 and 2.5,500 pg/mL for PGF2, and F2, -M, respectively. Acceptable precision and accuracy were obtained throughout the calibration curve ranges. This highly selective and sensitive method was successfully utilized to determine the endogenous levels of PGE2, PGF2,, and F2, -M in plasma samples from six (four male and two female) normal volunteers. The mean concentrations for each analyte were 0.755 pg/mL for PGE2, 5.70 pg/mL for PGF2, and 9.48 pg/mL for F2, -M. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Proteomics of Caenorhabditis elegans over-expressing human , -synuclein analyzed by fluorogenic derivatization,liquid chromatography/tandem mass spectrometry: identification of actin and several ribosomal proteins as negative markers at early Parkinson's disease stages

    BIOMEDICAL CHROMATOGRAPHY, Issue 3 2008
    Tomoko Ichibangase
    Abstract It has been known that the over-expression of , -synuclein, the main protein of Lewy bodies in Parkinson's disease (PD), leads to neurodegeneration in PD models. In this study, the changes in protein expression between the transgenic over-expressing human , -synuclein wild type (, -synWT) and the control Caenorhabditis elegans were elucidated by fluorogenic derivatization,liquid chromatography/tandem mass spectrometry (FD-LC-MS/MS) proteome analysis, which is a highly selective, sensitive, repeatable and quantitative method for protein identification. Because the , -synuclein wild-type worms showed moderate levels of dopamine loss without overt behavioral abnormalities, it was suggested that the changes in proteins in the , -synWT are related in the sequence of the formation of Lewy bodies. Among more than 400 protein peaks detected, actin and several ribosomal proteins were identified for the first time as negative markers at early PD stages. Actin was suggested to be one of the important targets in the elucidation of the etiology of neuronal diseases such as PD or other synucleinopathies. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Pityriarubins, Novel Highly Selective Inhibitors of Respiratory Burst from Cultures of the Yeast Malassezia furfur: Comparison with the Bisindolylmaleimide Arcyriarubin A

    CHEMBIOCHEM, Issue 12 2005
    Hans-Joachim Krämer Dr.
    Abstract Pityriasis versicolor is the most common skin mycosis in humans worldwide. Yeasts of the genus Malassezia, particularly M. furfur, a saprophyte occurring widely on human skin, are generally regarded as the causative agents. M. furfur is able to convert tryptophan into a variety of indole alkaloids, some of them showing biological properties that correlate well with certain clinical features of pityriasis versicolor. This suggests a possible role for these compounds in the pathophysiology of the disease. We here report that the novel pityriarubins A, B and C, isolated from cultures of the yeast, inhibit respiratory burst in human neutrophils, activated by various agents, in a highly selective, unexpected manner. The release of 5-lipoxygenase products after challenge of neutrophils with the calcium ionophore A23187 is also inhibited in a dose-dependent manner. These activities reflect the close structural relationship of pityriarubins to bisindolylmaleimides, which have recently gained great interest as protein kinase inhibitors. [source]

    Combined Pharmacophore Modeling, Docking, and 3D QSAR Studies of ABCB1 and ABCC1 Transporter Inhibitors

    CHEMMEDCHEM, Issue 11 2009

    Abstract Quinazolinones, indolo- and pyrrolopyrimidines with inhibitory effects toward ABCB1 (P-gp) and ABCC1 (MRP1) transporters were studied by pharmacophore modeling, docking, and 3D QSAR to describe the binding preferences of the proteins. The pharmacophore overlays between dual and/or highly selective inhibitors point to binding sites of different topology and physiochemical properties for MRP1 and P-gp. Docking of selective inhibitors into the P-gp binding cavity by the use of a structural model based on the recently resolved P-gp structure confirms the P-gp pharmacophore features identified, and reveals the interactions of some functional groups and atoms in the structures with particular protein residues. The 3D QSAR analysis of the dual-effect inhibitors allows satisfactory prediction of the selectivity index of the compounds and outlines electrostatics as most important for selectivity. The results from the combined modeling approach complement each other and could improve our understanding of the protein,ligand interactions involved, and could aid in the development of highly selective and potent inhibitors of P-gp and MRP1. [source]

    Efficient Synthesis of Dimethyl Ether over HZSM-5 Supported on Medium-Surface-Area ,-SiC Foam

    CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 10 2008
    Svetlana Ivanova Dr.
    Abstract In this study, we aimed to produce a highly selective and stable catalyst for the production of dimethyl ether by methanol dehydration. The activities were compared of different active phases of the employed system, zeolite HZSM-5 or , -alumina, supported on silicon carbide as foam, and it was found that the supported zeolite catalysts are more active than and as selective as the alumina-based catalysts. The as-prepared zeolite/SiC composites reveal good stability in long-term tests in the presence or absence of steam. The high stability is attributed to the presence of highly dispersed micrometer-sized zeolite particles, which make the active sites more accessible to the reactants and promote the quick transfer of the desired product, dimethyl ether, out of the catalyst bed, minimizing deactivation of the catalyst. [source]

    Inhibition of p38 MAP kinase during cellular activation results in IFN-,-dependent augmentation of IL-12 production by human monocytes/macrophages

    CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2001
    J. B. Marriott
    Interleukin-12 (IL-12) is a key immunomodulatory cytokine produced by antigen-presenting cells that promotes cellular immunity and enables the generation of protective immunity against intracellular pathogens and tumours. Therefore, modulation of IL-12 activity is a primary immunotherapeutic goal. However, little is known about its regulation. Signalling via p38 MAPK has been implicated in the control of inflammatory responses and is therefore a potential therapeutic target. We have used the highly selective p38 MAPK inhibitor (SB203580) to examine the effect of this pathway on the production of IL-12. Surprisingly, we found that SB203580 strongly up-regulated LPS induced IL-12p40 at the protein (intracellular and secreted) and mRNA levels in PBMC cultures. The effect on IL-12 was apparent using both T cell-independent and T cell-dependent stimuli but not in unstimulated cultures, indicating that activation signals are required. Furthermore, the production of IFN- , by T cells is crucial as production was not increased in LPS-stimulated, purified adherent monocytes/macrophages without the addition of exogenous IFN- ,. These results provide evidence that p38 MAPK has an unexpected suppressive effect on IL-12p40 gene transcription, and suggests interplay between p38 MAPK- and IFN- , -mediated signals in the regulation of IL-12 production by monocytes/macrophages. Furthermore, the importance of IL-12 as a key immunoregulatory cytokine suggests that the clinical application of pyrinidyl imidazole inhibitors, such as SB203580, may need to be reassessed. [source]