bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 11C‐labeled aromatics using aryl chromium tricarbonyl intermediates
Authors: Balatoni Julius A. , Adam Michael J. , Hall Laurance D. 
Published: October 2006

AbstractStable and 11C‐arylnitriles have been synthesized in 10 minutes by treatment of substituted fluoroaryl (R=H, p‐Me, o‐Me, p‐Cl) chromium tricarbonyl complexes with stable and 11C‐cyanide in DMSO at 115°–135°. Under the conditions used, decomplexation of the new complex occurs during the substitution reaction liberating the aryl nitrile product without need for the usual oxidative decomplexation step.
Synthesis and preliminary characterization of a new photoaffinity labeled adenosine nucleotide
Authors: Wong Shan S. , Glowacka Danuta , Johnson Dennis R. 
Published: October 2006

Abstract4‐Azido‐2‐nitrophenyl adenosyl pyrophosphate (ANAP), a new photoaffinity labeled adenosine nucleotide, was synthesized by coupling 4‐azido‐2‐nitrophenyl phosphate and adenosine 5′‐monophosphomorpholidate. Radioactive analogues were prepared from either [14C]‐AMP or iodination of 4‐azido‐2‐nitrophenol. ANAP was shown to be a competitive inhibitor of glucose‐6‐phosphate dehydrogenase against NADP with an inhibition constant of 9.5 μM. Iodination of ANAP did not affect its inhibition. Thus ANAP is a good photoaffinity analogue of NADP. It probably will also serve as an analogue of ATP or ADP.
[14C] acetylation of a glycosaminoglycan sulphate: Sulodexide
Authors: Breccia A. , Gattavecchia E. , Fini A. , Marchi E. , Tamagnone G. F. 
Published: October 2006

AbstractThe synthesis of [14C] labelled Sulodexide is reported. Sulodexide is a sulphated polysaccharide of the class of glycosaminoglycan, containing a heparin like fraction (70%), dermatan sulphate (20%) and other minor fractions. The heparin‐like fraction, suitably isolated from other components, was partially and selectively N‐desulphated, thus making few percent unit ‐NH2groups available for the labelling with [14C]‐acetic anhydride (specific activity 0.15 μCi/mg). Due to the small extent of modification, the sulphate to carboxylate group ratio remained practically unchanged on the heparin‐like fraction. Sulodexide was reconstituted adding to the labelled fraction the suitable amount of the other components; the chemical and biological properties of the final labelled Sulodexide were undistinguishable from those of the starting material.
Synthesis of the tritium labelled ß‐casomorphine analogues3H‐Phe‐Pro‐Gly‐OH and3H2‐Tyr‐Pro‐3H‐Phe‐pyrrolidide
Authors: Oehlke J. , Born I. , Neubert K. , Mittag E. , Niedrich H. 
Published: October 2006

AbstractThe precursor peptides H‐Phe(I)‐Pro‐Gly‐OH (III) and H‐Tyr(I2)‐Pro‐Phe(I)‐pyrrolidide (VIII) were synthesized by stepwise elongation from the C‐terminal end and by coupling of Boc‐Tyr(I2)‐Pro‐OH with H‐Phe(I)‐pyrrolidide and following deprotection of the Boc‐residue respectively. Catalytic dehalotritiation yielded tritated peptides with specific radioactivities of 450 and 1500 GBq/mmol respectively. Cleavage of3H2‐Tyr‐Pro‐3H‐Phe‐pyrrolidide by dipeptidylpeptidase IV resulted in fragments with specific radioactivities of 950 (3H2‐Tyr‐Pro) and 590 GBq/mmol (3H‐Phe‐pyrrolidide).
Towards the control and inhibition of glycation—the role of the guanidine reaction center with aldehydic and diketonic dicarbonyls. A mass spectrometry study
Authors: Saraiva Marco A. , Borges Carlos M. , Florêncio M. Helena 
Published: October 2006

AbstractGlycation of proteins by glucose and formation of end‐stage adducts (AGEs, advanced glycation end products) has been implicated in pathological mechanisms associated with diabetic complications, macrovascular disease, chronic and renal insufficiency, Alzheimer's disease, and aging. Of the carbonyl containing compounds involved in this process, α‐dicarbonyls have particular importance, being established as direct intermediates in the formation of well‐known AGEs. The guanidino group, present in arginine residues, suffers direct modifications by sugars and its derivatives, and is considered to be an important chemical basis, targeting the control and inhibition of glycation.Seven dicarbonyl compounds, aldehydic and diketonic, were reacted with guanidine, in an attempt to establish structure/activity relationships. Electrospray mass spectrometry, together with tandem mass spectrometry, was used to identify and characterize the reaction products. The reactivity of guanidine was found to vary with the dicarbonyls used. For glyoxal, a high amount of dihydroxyimidazolidine was formed, whereas for methylglyoxal, dihydroxyimidazolidine was slowly converted into hydroimidazolone. Interestingly, aqueous guanidine was found to prevent argpyrimidine formation. The formation of several amine‐dicarbonyl moieties was observed for the larger alkyl‐diketonic dicarbonyls reaction systems, in particular. Molecular structures, bearing a polar chain, of an imidazole ring, and a nonpolar one, of alkyl groups, located at both sides of the imidazole rings, were attributed to these moieties. Gas‐phase experiments suggested that the larger alkyl groups have a preference for being located at one of the sides of the imidazole rings. Moreover, the referred amine‐dicarbonyl moieties are formed via (dihydroxyimidazolidine − 2H2O) moieties. The latter (dihydroxyimidazolidine − 2H2O) moieties are formed in high amounts in the larger alkyl‐diketonic dicarbonyl reactions. Since these moieties react with dicarbonyl molecules, and react even faster with already modified amine functions, we can foresee that these species may be useful for controlling and inhibiting glycation of larger biomolecules, such as proteins. Copyright © 2006 John Wiley & Sons, Ltd.
Bor‐Verbindungen in der Krebs‐Therapie
Authors: Kliegel Wolfgang 
Published: October 2006

AbstractBlick von vorn auf die Bestrahlungseinrichtung eines Versuchsreaktors (FRJ‐1) der Kernforschungsanlage Jülich, mit der Neutroneneinfang ‐ Therapieversuche an Tumor‐Mäusen durchgeführt wurden. Man sieht die geschlossene abgeschirmte Ein‐ und Ausladevorrichtung, mit der die Tiere in einem Spezialkäfig bei laufendem Reaktor in einem Transportrohr hinein oder herausbewegt werden können.
Die Glucocorticoide
Authors: Schüppel R. 
Published: October 2006

AbstractDie Glucocorticoide stellen eine Gruppe von stark wirksamen Arzneistoffen dar, die in der modernen Therapie eine hervorragende Stellung einnehmen. Ihre Wirksamkeit erstreckt sich auf zahlreiche Krankheitserscheinungen, ihre Indikationen sind daher ungewöhnlich breit gefächert. Die Wirkung auf physiologische und pathologische Vorgänge beinhaltet jedoch auch das Risiko beachtlicher Komplikationen und Folgeschäden. Deren Kenntnis und Beachtung bei der Therapie ist für den therapeutischen Erfolg ebenso entscheidend wie die exakte Indikationsstellung.Die molekularbiologischen und biochemischen Wirkungsmechanismen der Glucocorticoide sind bisher nur teilweise aufgeklärt.
Kleines Fachwörterlexikon Pharmazie und Medizin
Authors: Schütter Reinhold 
Published: October 2006

AbstractDie Wissenschaft, die sich mit der Erforschung des Ursprungs der Wörter einschließlich der Fachausdrücke befaßt, nennt man Etymologie. Im Griechischen heißt „étymos”︁ wirklich, wahr und „lógos”︁ Darstellung, Kunde, Lehre, Beschreibung. Was sagt nun diese Wissenschaft über die medizinischen Fachbegriffe aus? Hier einige Beispiele.
Der Schlüssel zum Schloß II. Hansch‐Analyse, 3D‐QSAR undDe novo‐Design
Authors: Kubinyi Hugo 
Published: October 2006

AbstractDie Auffindung neuer Leitstrukturen und ihre gezielte Optimierung sind mehr denn je Kriterien für eine erfolgreiche Arzneimittelforschung. Computergestützte Methoden, wie Hansch‐Analyse, 3D‐QSAR undDe novo‐Design leisten dazu einen wichtigen Beitrag.
Molekulare Ähnlichkeit. 2. Strukturbasierter Entwurf von Wirkstoffen
Authors: Kubinyi Hugo 
Published: October 2006

AbstractDer Entwurf neuer Wirkstoffe berücksichtigt Kriterien der molekularen Ähnlichkeit. Jede Optimierung einer durch Zufall gefundenen oder gezielt hergestellten Leitstruktur und jedes strukturbasierte oder computergestützte Design neuer Analoga geht von Ähnlichkeitsbetrachtungen der Wirkstoffe bzw. ihrer Komplementarität zu einer Bindestelle aus. Oft dienen natürliche Liganden als Vorbild für die Entwicklung eines Wirkstoffs; in günstigen Fällen stehen die 3D‐Strukturen des biologischen Targets und seiner Liganden‐Komplexe zur Verfügung. Arbeitshypothesen zum Einfluß struktureller Änderungen auf die biologische Aktivität bestimmen den Gang der chemischen Synthesen. Das rationale Design von Wirkstoffen wird an Hand von drei aktuellen Beispielen der industriellen Arzneimittelforschung vorgestellt. Neben der Optimierung der strukturbasiert entwickelten Wirkstoffe wird insbesondere auch die Problematik der Erzielung einer ausreichenden Bioverfügbarkeit behandelt.
Study of the thermal behaviour of alipharomatic polyesters around the glass–rubber transition region by thermomechanical analysis: the mobile and rigid amorphous fraction
Authors: Karayannidis George , Kirikou Eleni , Roupakias Christos , Papageorgiou George 
Published: October 2006

AbstractThe objective of this work was the study using thermomechanical analysis (TMA) of a peculiar behaviour, which was observed some years ago, around the glass–rubber transition region in some thermoplastic alipharomatic polyesters. For this purpose a series of nine alipharomatic polyesters was prepared by the two‐stage melt polycondensation method in a glass batch reactor and subjected to TMA in both penetration and expansion mode. Differential scanning calorimetry (DSC) was additionally used and the results are discussed focusing mainly on the first derivative curve of TMA thermograms in the penetration mode. From this curve, which shows two distinct peaks, the first peak could be attributed to the glass transition temperature (Tg) of the mobile amorphous fraction, since the value coincides with that obtained from DSC and is due to the abrupt shrinkage of the amorphous part of the sample. The second peak (up to 40 °C higher than Tg) is due most probably to the softening of the rigid amorphous fraction and the passage of the polymeric sample from the glass region to the cold crystallization region. When the sample is more crystalline than amorphous then the first peak is smaller or is completely absent. Copyright © 2006 Society of Chemical Industry
Fluorescence resonance energy transfer by quencher adsorption into hydrogels containing fluorophores
Authors: Okawa Kaori , Miyata Takashi , Uragami Tadashi 
Published: October 2006

AbstractWe synthesized anionic hydrogels containing fluorophores and investigated the adsorption of a cationic quencher having an amino group into hydrogels by fluorescence resonance energy transfer (FRET). FRET from the fluorophore to the quencher in hydrogels was examined by fluorescence intensity and fluorescence decay using a fluorescence spectrophotometer and femtosecond laser spectroscopy. The fluorescence intensity of the fluorophore‐containing hydrogels decreased rapidly with increasing amounts of adsorbed cationic quencher. The fluorescence emission of the fluorophore in the quencher‐adsorbed hydrogels containing fluorophores decayed more rapidly than that of the original hydrogels. The aforementioned result indicates that the fluorescence of the fluorophore‐containing hydrogels is quenched due to FRET from the fluorophore to the quencher as the cationic quenchers can approach the fluorophores in hydrogels by electrostatic interactions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3245–3252, 2006
Structural anisotropy in friction‐deposited layers of polystyrene
Authors: Elzein Tamara , Kreim Virginie , Ghorbal Achraf , Bistac Sophie 
Published: October 2006

AbstractFriction‐deposited layers of atactic polystyrene (PS) on inert and OH‐grafted gold substrates were the subject of this study to establish a relationship between the friction process and the resulting anisotropy of the transferred polymer chains. We show, by using polarization‐modulation infrared reflection‐absorption spectroscopy that the deposited PS chains involve an anisotropy in which PS main backbone is rather perpendicular to the friction support, fact that is surprising when compared with the majority of polymers where the anisotropy is along the sliding direction. Moreover, our calculation of the orientation angles revealed that PS chains are more perpendicular in the transferred layers than in spin‐coated films. This particular anisotropy is probably due to a parallel reorientation of the phenyl ring on the friction support whatever the surface chemistry is. On the other hand, this study was useful to rectify the assignment of infrared bands unclearly reported in the literature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3272–3281, 2006
Solvation characteristics of a model water‐soluble polymer
Authors: Hammouda Boualem 
Published: October 2006

AbstractThe model water‐soluble polymer poly(ethylene oxide) was used to investigate solvation characteristics in mixtures of d‐water (deuterated water) and d‐alcohols (deuterated alcohols). Three d‐alcohols have been used: d‐methanol, d‐ethanol, and d‐ethylene glycol. Small angle neutron scattering was used to monitor the solvation properties of poly(ethylene oxide) in the d‐solvent mixtures. Nonideal solvent mixing was observed throughout. Solvent mixtures were found to be more effective solvating agents than individual solvents. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3195–3199, 2006
Structure of gum arabic in aqueous solution
Authors: Dror Yael , Cohen Yachin , Yerushalmi‐Rozen Rachel 
Published: October 2006

AbstractGum arabic, a natural polysaccharide derived from exudates of Acacia senegal and Acacia seyal trees, is a commonly used food hydrocolloid. The complex chemical structure of the gum has been widely studied revealing a multifraction material consisting mainly of a highly branched polysaccharide and a protein–polysaccharide complex (GAGP) as a minor component. This work investigates its mesoscopic structure in aqueous solution by small‐angle X‐ray and neutron scattering combined with cryotransmission electrons microscopy. Scattering measurements reveal an intricate shape composed of many spheroidal aggregates assigned to the polysaccharide with a small amount of larger coils. A scattering peak is observed at moderate to high concentrations, the spacing of which exhibits a c−1/3 power law relation to polymer concentration (c). Upon addition of salt, this peak disappears, indicating its electrostatic nature. The large coils contribute a q−2 power law at the low scattering vector (q) range. However, at low concentration in which the interaggregate peak is not observed, a q−1 power law at the low q range indicates the possible existence of a fraction with a locally extended conformation. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3265–3271, 2006
Atmospheric Pressure Glow Discharge CVD of Al2O3 Thin Films
Authors: Hodgkinson John L. , Sheel David W. , Yates Heather M. , Pemble Martyn E. 
Published: October 2006

AbstractSummary: We report for the first time deposition of aluminium oxide thin films by APGD, plasma‐enhanced CVD. This approach allows deposition at substantially lower substrate temperatures than normally used in atmospheric pressure based processing. The films are analysed by SEM, XPS, RBS, XRD, and optical properties. It is demonstrated that the APGD approach yields films which are essentially smooth, conformal and free from pinholes or other imperfections.SEM image of alumina film on glass (film G).magnified imageSEM image of alumina film on glass (film G).
Retracted: Dyeing Behaviour of Low Temperature Plasma Treated Wool
Authors: Kan Chi‐wai , Yuen Chun‐wah Marcus 
Published: October 2006

AbstractSummary:In this paper, the effects of low temperature plasma (LTP) treatments on the dyeing properties of the wool fibres were studied. The wool fibres were treated with oxygen plasma and three types of dyes commonly used for wool dyeing, namely: (i) acid dye, (ii) chrome dye and (iii) reactive dye, were used in the dyeing process. For acid dyeing, the dyeing rate of the LTP‐treated wool fibre was greatly increased, but the final dyeing exhaustion equilibrium did not show any significant change. For the chrome dyeing, the dyeing rate of the LTP‐treated wool fibre was also increased, but the final dyeing exhaustion equilibrium was only increased to a small extent. In addition, the rate of afterchroming process was similar to the chrome dyeing process. For the reactive dyeing, the dyeing rate of the LTP‐treated wool fibre was greatly increased, and the final dyeing exhaustion equilibrium was also increased significantly. With such results, one could conclude that the LTP treatments improve the dyeing behaviour of wool fibres in different dyeing systems.SEM picture of an untreated wool fibre.
Calculation of Detonation Velocity, Pressure, and Electric Sensitivity of Nitro Arenes Based on Quantum Chemistry
Authors: Wang Guixiang , Xiao Heming , Ju Xuehai , Gong Xuedong 
Published: October 2006

AbstractThe DFT‐B3LYP method, with basis set 6‐31G*, is employed to optimize molecular geometries and electronic structures of thirty‐nine nitro arenes. The averaged molar volume (V) and theoretical density (ϱ) are estimated using the Monte‐Carlo method, based on 0.001 electrons/bohr3 density space and a self‐compiled program. The detonation velocity (D) and pressure (P) of the explosives are estimated by using the Kamlet–Jacbos equation on the basis of the theoretical density and heat of formation (ΔfH), which is calculated using the PM3 method. The reliability of this theoretical method and results are tested by comparing the theoretical values of ϱ and D with the experimental or referenced values. The theoretical values of D and P are correlated with the experimental values of electric sensitivity (EES). It is found that, for the nitro arenes, there is a linear relationship between the square of detonation velocity (D2) or detonation pressure (P) and electric sensitivity (EES), which suggests that such a theoretical approach can be used to predict or judge the magnitude of EES, which is difficult to measure in the molecular design of energetic materials. In addition, we have discussed the influence of the substituted groups and the parameters of the electronic structure on density, detonation velocity, pressure, and electric sensitivity, and have shown that the substituted groups have the effect of activity or insensitivity, and that the influence of Q‐NO2 and ELUMO is important.
Characterization of Aluminum Powders: II. Aluminum Nanopowders Passivated by Non‐Inert Coatings
Authors: Gromov Alexander , Ilyin Alexander , Förter‐Barth Ulrich , Teipel Ulrich 
Published: October 2006

AbstractResults of DTA‐TG investigation and chemical analysis of electro‐exploded aluminum nanopowders, passivated and/or coated with the non‐inert reagents: nitrocellulose (NC), oleic acid (C17H33COOH) and stearic acid (C17H35COOH), which were suspended in kerosene and ethanol, amorphous boron, nickel, fluoropolymer, ethanol and air (for comparison), are discussed. Surface protection of aluminum nanopowders by coatings of different origin results in significant advantages in the energetic properties of the powders. Aluminum nanopowders with a protecting surface show increased stability to oxidation in nitrogen, air and in water during storage period. On the basis of the experimental results, a diagram of the formation and stabilization of the coatings is proposed. The kinetics of the interaction of aluminum nanopowders with nitrogen, air and water is discussed. Recommendations concerning the efficiency of non‐inert reagent passivation are proposed on the basis of comprehensive analysis of the experimental data.
Study of Combustion Properties of a Solid Propellant by Highly Time‐Resolved Passive FTIR
Authors: Zhang Liming , Zhang Lin , Li Yan , Liu Bingping , Wang Junde 
Published: October 2006

AbstractWith a time resolution of 0.125 s and a spectral resolution of 4 cm−1, emission spectra of the combustion process of a solid propellant were recorded by highly time‐resolved passive FTIR. Some gaseous combustion products, such as H2O, CO, CO2, NO and HCl, were distinguished by the characteristic emission band of each molecule. The equation for flame temperature calculation based on the diatomic molecule emission fine structure theory was improved through judicious utilization of the spectral running number ‘m’ which makes the temperature measurement simpler and faster. Some combustion information of the solid propellant had been given including the characteristic spectral profile, the distribution of the absolute spectral energy, the distribution of the combustion flame temperature, and the concentration distributions of HCl and NO versus burning time. The results will provide theoretical and experimental bases for improving the formula and raising combustion efficiency of solid propellant, and developing the design of rocket motor, infrared guidance and antiguidance systems.
QSPR Study on the Aqueous Solubility (−lgSw) and n‐Octanol/Water Partition Coefficients (lgKow) of Polychlorinated Dibenzo‐p‐dioxins (PCDDs)
Authors: Yang Guo‐Ying , Yu Jing , Wang Zun‐Yao , Zeng Xiao‐Lan , Ju Xue‐Hai 
Published: October 2006

AbstractOptimized calculation of 75 Polychlorinated Dibenzo‐p‐dioxins (PCDDs) and their parent compound DD was carried out at B3LYP/6‐31G* level with GAUSSIAN 98 program. The structural parameters identified with the Theoretical Linear Solvation Energy Relationship (TLSER) model were employed as theoretical descriptors in the Quantitative Structure–Property Relationship (QSPR) models derived to predict the aqueous solubility (−lgSw) and n‐octanol/water partition coefficients (lgKow) of PCDDs. The regression model obtained to predict −lgSw contains only one variable: the mean molecular polarizability (α). The best fitted equation for the correlation between −lgSw and α of 12 PCDDs was −lgSw=−3.6425+0.0693α with r2 as 0.9776, Standard Deviation (SD) as 0.30, and suggesting high accuracy of the −lgSw predicting model. At the same time, there exists high correlation (r2=0.8862) between n‐octanol/water partition coefficients (lgKow) and the mean molecular polarizability (α), and the SD is small. The mean molecular polarizability (α) is the only theoretical descriptor used in the QSPR model derived to predict lgKow.
The geometry of logconcave functions and sampling algorithms
Authors: Lovász László , Vempala Santosh 
Published: October 2006

AbstractThe class of logconcave functions in ℝnis a common generalization of Gaussians and of indicator functions of convex sets. Motivated by the problem of sampling from logconcave density functions, we study their geometry and introduce a technique for “smoothing” them out. These results are applied to analyze two efficient algorithms for sampling from a logconcave distribution inndimensions, with no assumptions on the local smoothness of the density function. Both algorithms, the ball walk and the hit‐and‐run walk, use a random walk (Markov chain) to generate a random point. After appropriate preprocessing, they produce a point from approximately the right distribution in timeO*(n4) and in amortized timeO*(n3) ifnor more sample points are needed (where the asterisk indicates that dependence on the error parameter and factors of lognare not shown). These bounds match previous bounds for the special case of sampling from the uniform distribution over a convex body.© 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007