bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two‐Step Simultaneous Distillation and Slolvent Extraction for Isolation Both Free and Bound Aroma Intobacco
Authors: Hu Yaqin , Cai Jibao , Zhu Xiaolan , Gao Yun , Su Qingde 
Published: June 2006

AbstractIn this investigation, a novel two‐step simultaneous distillation and solvent extraction (two‐step SDE) method was developed to isolate both free and bound aroma in tobacco. Firstly, free aroma were extracted into dichloromethane by SDE for 4 h with SDE sample solution at pH 5.5. Then the SDE sample solution was adjusted to pH 2.5, bound aroma were hydrolyzed, and released as free aroma extracted by fresh dichloromethane. Following, both the free and bound aroma were analyzed by gas chromatography (GC) and gas chromatography‐mass spectrometry (GC‐MS).The whole isolation procedure of both free and bound aroma was carried out in one SDE apparatus and using one same sample. Especially, the procedure of isolation of bound aroma was greatly simplified. To apply and validate the proposed two‐step SDE method, a traditional method were also used to isolate the bound aroma. The total bound aroma obtained by the proposed two‐step SDE method and the traditional method were 119.83 mg kg‐1 and 88.9 mg kg‐1, respectively. For isolation of bound aroma, the proposed two‐step SDE method was of better extraction recovery, less labourious, solvent and time consuming than the traditionalmethod.
Development of a Model to Predict Partition Coefficient of Organic Pollutants in Cloud Point Extraction Process
Authors: Shahmirani Samareh , Vasheghani Farahani Ebrahim , Ghasemi Jahanbakhsh 
Published: June 2006

AbstractA quantitative structure property relationship (QSPR) study has been performed to establish a model to relate structural descriptors of 45 organic compounds to their partition coefficients in water‐hexadecylpyridinium chloride (CPC) micelles at 298K using partial least squares (PLS). 510 of six different categories of structural descriptors were calculated by Dragon software. The descriptors with 0.9 mutually pair correlations and with less than 0.1 with dependent variables were excluded at the early stage of the preprocessing of the structural data matrix. The data set was randomly divided into two groups: training set (40 molecules) and test set (5 molecules). In the final model 50 of the most effective of the structural descriptors on the partition coefficient were remained to model building by PLS calibration method. The optimum number of latent variables 5, which spanned 80% of the original variations of data matrix, was selected using leave one out cross validation method. Prediction ability of the model was tested by prediction of the partition coefficients of five unknown compounds and the mean relative error of prediction was 3.60%. The outliers were treated using leverage and score plots of the first third principal components. The efficiency of the new model was compared with Abraham model and it was found that the proposed model has more prediction ability.
A Chemometric Approach to the Investigation of Major and Minor Ion Chemistry in Lake Como (Lombardia, Northern Italy)
Authors: Giussani Barbara , Dossi Carlo , Monticelli Damiano , Pozzi Andrea , Recchia Sandro 
Published: June 2006

AbstractA chemometric approach based on Principal Component Analysis (PCA) has been proposed, in order to study chemical features (major and minor ions, total alkalinity, dissolved silica) of surface and deep waters of Lake Como (Northern Italy). The method allowed us to investigate the correlations between the analyzed ions in an easy‐to‐see way, using bi‐dimensional graphs. In wintertime, the ionic composition of Lake Como waters seems to be mainly related to the geological composition of the lake basin, with a crystalline bedrock on the northern side and a sedimentary cover in the southern part. The presence of contaminants such as bromide and nitrite in water columns is also evidenced and discussed.
Comparison of effects of in vivo nitrogen dioxide exposure starting from different periods on alveolar macrophage activity, assessed by a chemiluminescence technique in Brown‐Norway rats
Authors: Kumae Takashi , Arakawa Hatsuko 
Published: June 2006

AbstractNitrogen dioxide (NO2) has been extensively studied for its immune modulating effects on pulmonary cells. Alveolar macrophages (AMs) play an important role in pulmonary immunity. The Brown‐Norway (BN) rat has been studied as a high‐risk model of allergic diseases. In this study, BN rats were exposed to NO2 from the embryonic or weanling period (EP or WP, respectively). To evaluate the effects of NO2 exposure on pulmonary immunity, the activity levels of rat AMs were assessed as reactive oxygen species‐generating capacity, measured by a chemiluminescence (CL) technique, and as cytokine‐producing ability. Except for 0.2 ppm of NO2 exposure, the CL responses of AMs obtained from the WP group at 12 weeks old were suppressed significantly. Changes of the cytokine‐producing levels suggest that inflammatory reactions are terminated at 12 weeks in the EP group. Correlations between the CL responses and the cytokine levels reveal that NO2 exposure may modulate the direction of AM activation. The CL technique is thought to be useful to evaluate changes in AM activity. In this study, the results suggest that, using the high‐risk model of allergic diseases, NO2 exposure from the weanling period has stronger effects on AM activity.Copyright © 2006 John Wiley & Sons, Ltd.
Chemiluminescent determination of total antioxidant capacity during winemaking
Authors: Girotti Stefano , Fini Fabiana , Bolelli Luca , Savini Luigi , Sartini Elisa , Arfelli Giuseppe 
Published: June 2006

AbstractThe total antioxidant capacity (TAC) of five different wines (four red and one white) was determined in five different steps of winemaking carried out in a commercial wine cellar by a chemiluminescence (CL) assay. The CL method is suitable to determine the antioxidant capacity of beverages, and preliminary trials showed that the TAC immediately after the bottle was opened was greater than the day after (about 25% decrease). Immediate analysis or a correct sample storage is therefore necessary. The wines were characterized by different levels of total phenolics and TAC: these differences were related to grape composition and winemaking technologies. The TAC values were the highest immediately after devatting. The TAC suffered the highest decrease (30–50%) after the clarification procedure, which may be due to the fining agents used and to oxygen contact, then remained more or less constant in the subsequent steps. Copyright © 2006 John Wiley & Sons, Ltd.
Bovine serum albumin displays luciferase‐like activity in presence of luciferyl adenylate: insights on the origin of protoluciferase activity and bioluminescence colours
Authors: Viviani Vadim R. , Ohmiya Y. 
Published: June 2006

AbstractLuciferyl adenylate, the key intermediate in beetle bioluminescence, is produced through adenylation of d‐luciferin by beetle luciferases and also by mealworm luciferase‐like enzymes which produce a weak red chemiluminescence. However, luciferyl adenylate is only weakly chemiluminescent in water at physiological pH and it is unclear how efficient bioluminescence evolved from its weak chemiluminescent properties. We found that bovine serum albumin (BSA) and neutral detergents enhance luciferyl adenylate chemiluminescence by three orders of magnitude, simulating the mealworm luciferase‐like enzyme chemiluminescence properties. These results suggest that the beetle protoluciferase activity arose as an enhanced luciferyl adeny‐late chemiluminescence in the protein environment of the ancestral AMP‐ligase. The predominance of luciferyl adenylate chemiluminescence in the red region under most conditions suggests that red luminescence is a more primitive condition that characterized the original stages of protobioluminescence, whereas yellow‐green bioluminescence may have evolved later through the development of a more structured and hydrophobic active site. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of a 21 day metabolic study on serum opsonic activity in female college students, assessed by a chemiluminescence technique
Authors: Kumae Takashi , Kogure Hiroko , Nishimuta Mamoru , Kodama Naoko , Yoshitake Yutaka 
Published: June 2006

AbstractA metabolic study to evaluate nutritional balance, in which subjects have to eat all the foods supplied and maintain a set schedule, is thought to be stressful for the subjects. The effects of stress on the immune system have been studied extensively. However, there are no studies of non‐specific immunological changes during a metabolic study. Serum opsonic activity (SOA) is a direct and suitable indicator of non‐specific humoral immunity. In this study, we used luminol‐dependent chemiluminescence (LmCL) to measure reactive oxygen species (ROS) generation from pooled human neutrophils as an indicator of SOA. We also measured serum immunoglobulin levels and plasma myeloperoxidase (MPO) activity. Eleven female college students took part in this 21 day metabolic study after giving their written informed consent. The results obtained suggest that the metabolic study has almost no effect on immunoglobulin levels. According to MPO levels, neutrophils in vivo may be deactivated to some minor extent. In contrast to these results, peak time (PT) and peak height (PH) of LmCL were changed significantly during the metabolic study. In conclusion, SOA increased during the 21 day metabolic study. There was no significant correlation between SOA and serum immunoglobulin levels on any of the study days. Copyright © 2006 John Wiley & Sons, Ltd.
Nitric Oxide‐Induced Fluorescence Enhancement by Displacement of Dansylated Ligands from Cobalt
Authors: Lim Mi Hee , Kuang Chaoyuan , Lippard Stephen J. 
Published: June 2006

AbstractThe cobalt complexes [Co(Ds‐AMP)2] (1) and [Co(Ds‐AQ)2] (2), where Ds‐AMP and Ds‐AQ are the conjugate bases of dansyl aminomethylpyridine (Ds‐HAMP) and dansyl aminoquinoline (Ds‐HAQ), respectively, were synthesized in two steps as fluorescence‐based nitric oxide (NO) sensors and characterized by X‐ray crystallography. The fluorescence of the two complexes was significantly quenched in CH3CN or CH3OH compared to that of the free Ds‐HAMP or Ds‐HAQ ligands. Addition of NO to a CH3CN solution of 1 or 2 enhanced the integrated fluorescence emission by factors of 2.1(±0.3) or 3.6(±0.4) within 35 or 20 min, respectively. Introduction of NO to methanolic solutions of the complexes similarly increased the fluorescence by 1.4(±0.1) for 1 or 6.5(±1.4) for 2 within 1 h. These studies demonstrate that 1 and 2 can monitor the presence of NO with turn‐on emission and that their fluorescence responses are more rapid than those of previously reported cobalt systems in coordinating solvents such as CH3CN and CH3OH. 1H NMR and IR spectroscopic data revealed the formation of a {Co(NO)2}10 cobalt–dinitrosyl adduct, with concomitant dissociation of one ligand from the cobalt center, as the metal‐containing product of the NO reactions, a result indicating NO‐induced ligand release to be the cause of the fluorescence increase.
The Coordination Chemistry of FeCl3and FeCl2to Bis[2‐(2,3‐dihydroxyphenyl)‐6‐pyridylmethyl](2‐pyridylmethyl)amine: Access to a Diiron(III) Compound with an Unusual Pentagonal‐Bipyramidal/Square‐Pyramidal Environment
Authors: Machkour Ahmed , Thallaj Nasser K. , Benhamou Laila , Lachkar Mohammed , Mandon Dominique 
Published: June 2006

AbstractCoordination of FeCl3to the title ligand yields a mononuclear iron(III) complex1, which was characterized by spectroscopic techniques and X‐ray diffraction. The ligand is (κ3‐N) tridentate and the metal, which lies in a pseudo‐octahedral environment, is bound to a phenolate group from the catechol substituent. The dichloroiron(II) complex2was easily obtained by metalation of the ligand with FeCl2and characterized by various spectroscopic techniques. In their cyclic voltammograms both1and2display the same reversible FeII/FeIIIwave atE1/2=10 mV (vs. SCE). Reduction of compound1with Zn/Hg yields2′, which displays identical properties to2. Taken together, these findings indicate that in spite of the different oxidation state of the metal in2, no major geometrical/structural change is observed at the metal center with respect to1. The reaction of2with dioxygen in the absence of organic substrates proceeds extremely rapidly and yields compound3, which is a diiron(III) derivative whose X‐ray crystal structure is also reported. The possibility of a radical‐based mechanism is discussed. Compound3displays an unusual geometry: one iron(III) center is seven‐coordinate, whereas the other lies in a square‐pyramidal environment. The two iron atoms are bridged by the catecholato substituents. To the best of our knowledge,3is the first example of a seven‐coordinate iron(III) derivative with tris(2‐pyridylmethyl)amine ligands.
Adsorption and Dynamics of Long‐Range Interacting Fullerenes in a Flexible, Two‐Dimensional, Nanoporous Porphyrin Network
Authors: Kiebele Andreas , Bonifazi Davide , Cheng Fuyong , Stöhr Meike , Diederich François , Jung Thomas , Spillmann Hannes 
Published: June 2006

AbstractHerein, a detailed investigation of the adsorption and dynamics of C60 and C70 fullerenes hosted in a self‐assembled, two‐dimensional, nanoporous porphyrin network on a solid Ag surface is presented. Time‐resolved scanning tunneling microscopy (STM) studies of these supramolecular systems at the molecular scale reveal distinct host–guest interactions giving rise to a pronounced dissimilar mobility of the two fullerenes within the porphyrin network. Furthermore, long‐range coverage‐dependent interactions between the all‐carbon guests, which clearly affect their mobility and are likely mediated by a complex mechanism involving the Ag substrate and the flexible porphyrin host network, are observed. At increased fullerene coverage, this unprecedented interplay results in the formation of large fullerene chains and islands. By applying a lattice gas model with nearest‐neighbor interactions and by evaluating the fullerene‐pair distribution functions, the respective coverage‐dependent guest–guest interaction energies are estimated.
Außenputz auf Leichtmauerwerk – Vermeiden schädlicher Risse
Authors: Schubert Peter 
Published: June 2006

AbstractAußenputz auf Leichtmauerwerk – Vermeiden schädlicher Risse
Risse im Außenputz, durch die Wasser in die Außenwand eindringen kann – also schädliche Risse, Rißbreite etwa über 0,2 mm –, sind unbedingt zu vermeiden. Derartige Risse können durch verschiedene Ursachen hervorgerufen werden. Sie lassen sich Ursachengruppen zuordnen. Einzelrisse im Putzgrund müssen i. w. durch konstruktive Maßnahmen vermieden werden. Die sach‐ und normgerechte Ausführung des Putzgrundes ist eine weitere wichtige Voraussetzung für das Vermeiden schädlicher Risse im Außenputz. Dieser muß in seinen Eigenschaften besonders an den Putzgrund Leichtmauerwerk angepaßt sein. Um dies zu gewährleisten, müssen die relevanten Eigenschaften von Putz und Putzgrund bekannt sein oder durch Prüfung ermittelt werden. Derzeit verfügbare Eigenschaftswerte und Eigenschaftszusammenhänge wurden ausgewertet und bewertet sowie geeignete Prüfverfahren angegeben. Die Rißsicherheit kann näherungsweise mit Hilfe von Rißkriterien beurteilt werden, die vorgestellt und erläutert werden. Mit dem heute wesentlich erweiterten und verbesserten Erkenntnis‐ und Erfahrungsstand lassen sich schädliche Risse im Außenputz, die auf einen für den jeweiligen Putzgrund ungeeigneten Putz zurückzuführen sind, noch sehr viel sicherer vermeiden als bisher.
Zur Haftscherfestigkeit bei Mauerwerk aus Leichtbetonsteinen
Authors: Glitza Horst , Jäger Wolfram , Burkert Toralf 
Published: June 2006

AbstractDie Anforderungswerte für Haftscherfestigkeit im Anhang A von DIN 1053‐1 beziehen sich auf das Prüfverfahren nach DIN 18555‐5 unter Verwendung eines Kalksandsteins als Referenzstein. In der Literatur werden für Leichtbetonsteine demgegenüber deutlich höhere Haftscherfestigkeiten angegeben. Die dort zu findenden Werte sind jedoch teilweise mit sehr großen Streuungen behaftet. Im Beitrag wird den Ursachen hierfür nachgegangen und ein Vorschlag für eine Anpassung der Anforderungs‐ und Rechenwerte für Mauerwerk aus Leichtbetonsteinen im Rahmen der derzeit laufenden Überarbeitung der DIN 1053‐1 unterbreitet.
Eigenschaftswerte von Kalksandsteinen unter Zugbeanspruchung
Authors: Schubert Peter , Graubohm Markus 
Published: June 2006

AbstractDie Zug‐ bzw. Biegezugfestigkeit von Mauersteinen beeinflußt die Zug‐, Biegezug‐ und Schubfestigkeit von Mauerwerk i. d. R. entscheidend. Die für die Mauerwerkbemessung in DIN 1053‐1 zugrunde gelegten Eigenschaftswerte der Mauersteine sind stark pauschaliert und stammen aus über 10 Jahre alten Untersuchungen. Für die Überarbeitung der DIN 1053‐1 bzw. das Anwendungsdokument zu Eurocode 6 ist eine aktualisierte Auswertung und Bewertung der derzeit verfügbaren Untersuchungsergebnisse erforderlich. Dies ist Inhalt des Beitrages. Die Untersuchungsergebnisse werden statistisch ausgewertet, in Diagrammen sowie Tabellen dargestellt und für die Anwendung in den Technischen Regelwerken aufbereitet.
Sugar‐Derived Ras Inhibitors: Group Epitope Mapping by NMR Spectroscopy and Biological Evaluation
Authors: Peri Francesco , Airoldi Cristina , Colombo Sonia , Mari Silvia , Jiménez‐Barbero Jesús , Martegani Enzo , Nicotra Francesco 
Published: June 2006

AbstractNovel inhibitors of Ras protein activation have been found, containing a bicyclic core derived from D‐arabinose and benzyl and phenylhydroxylamine moieties. NMR studies (trNOE, saturation‐transfer difference, STD) of the binding between these molecules and human p21 h‐Ras are reported. A pharmacophore mapping indicates that both the benzyl and the phenylhydroxylamine moieties are essential for protein binding. Molecules lacking one of these groups were synthesized and tested to confirm this hypothesis, and no interaction with Ras in vitro, nor biological activity in mammalian cells was observed. Our studies led to the development of molecules that selectively inhibit Ras‐dependent cellular growth in mammalian cells. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Cationic Rhodium(I)/Modified‐BINAP Catalyzed [2+2+2] Cycloaddition of Alkynes with Nitriles
Authors: Tanaka Ken , Suzuki Nanami , Nishida Goushi 
Published: June 2006

AbstractCationic rhodium(I)/modified‐BINAP complexes catalyze a chemo‐ and regioselective [2+2+2] cycloaddition of a wide variety of alkynes and nitriles leading to highly functionalized pyridines under mild reaction conditions. The asymmetric variant of this reaction, enantioselective desymmetrization of substituted malononitriles, also proceeded to give enantio‐enriched bicyclic pyridines which possess a tertiary or quaternary stereocenter. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Volatile constituents of Ailanthus excelsa Roxb.
Authors: Tzakou Olga , Said Ataa , Farag Ahmed , Rashed Khaled 
Published: June 2006

AbstractThe volatile constituents from fresh aerial parts of Ailanthus excelsa were analysed by GC and GC–MS. Fatty acids and their esters represented the main fraction (40.9%) of the obtained oil, with 9,12,15‐octadecatrienoic acid methyl ester (linolenic acid) being the main component (13.7%). The dominant component of the oil was phytol (26.7%). Copyright © 2006 John Wiley & Sons, Ltd.
Primary beer fermentation by immobilised yeast—a review on flavour formation and control strategies
Authors: Willaert Ronnie , Nedovic Viktor A 
Published: June 2006

AbstractImmobilised cells are increasingly being used in bio‐industries and may also have benefits for the brewing industry. The major challenge to applying this technology successfully in breweries is focused on the main fermentation in combination with the secondary fermentation. In particular, the control and fine‐tuning of the flavour profile during the main fermentation require further investigation. In this review, the influence of immobilised cell technology on the production of the flavour‐active compounds (i.e. higher alcohols, esters and vicinal diketones) is discussed. Control strategies that are based on the manipulation of parameters during fermentation such as temperature, feed volume, wort gravity, wort composition and aeration are explained. Finally, bioreactor configurations that may facilitate immobilised cells in performing the primary fermentation are evaluated. Copyright © 2006 Society of Chemical Industry
Study of a continuous reactor for selective solvent extraction of haemorphins in the course of peptic haemoglobin hydrolysis
Authors: Froidevaux Renato , Vercaigne‐Marko Dominique , Kapel Romain , Lecouturier Didier , Chung Sookhyun , Dhulster Pascal , Guillochon Didier 
Published: June 2006

AbstractThe continuous hydrolysis of bovine haemoglobin at pH 3 in a triphasic reactor was studied in order to prepare two pure transient and hydrophobic opioid peptides in one step. A continuous stirred‐tank reactor was designed to extract continuously and selectively LVV‐haemorphin‐7 and VV‐haemorphin‐7 by a butan‐2‐ol–octan‐1‐ol mixture in the course of bovine haemoglobin hydrolysis by pepsin immobilised on A568 Duolite resin. The residence time in the aqueous and organic phases was maintained at 1 h. This system allowed a steady state to be achieved for haemorphin concentrations in each phase and the pepsin stability to be maintained. Finally, success was achieved in producing and extracting continuously the two haemorphins in the aqueous/butan‐2‐ol–octan‐1‐ol biphasic medium for more than 10 bed volumes of the reactor. Copyright © 2006 Society of Chemical Industry
High resolution 3T MRI for the assessment of cervical and superficial cranial arteries in giant cell arteritis
Authors: Markl Michael , Uhl Markus , Wieben Oliver , Neß Thomas , Langer Mathias , Hennig Jürgen , Bley Thorsten A. 
Published: June 2006

AbstractA new high‐resolution MR protocol for the combined assessment of neurovascular arterial anatomy and subsequent evaluation of inflammatory disease in cranial vessels walls has been investigated. First‐pass contrast‐enhanced MR angiography (CE‐MRA) in combination with parallel imaging at high field permits the depiction of the neurovascular geometry with large coverage, including the aortic arch, supraaortic vessels, and almost the entire head, with high, submillimeter detail. Utilizing the remaining contrast agent, postcontrast T1‐weighted turbo spin‐echo (TSE) imaging was used to generate late enhancement images of the vessel walls to assess the morphology and potential inflammatory changes in cranial arteries with high in‐plane (195 × 260 μm2) spatial resolution. As a result, a combined analysis of neurovascular arterial anatomy as well as cranial vessel wall inflammations could be achieved in less than 45 minutes in all studies. The feasibility and clinical value for the diagnosis of rheumatologic diseases and simultaneous arteriosclerotic involvement was demonstrated in seven patients with suspected giant cell arteritis (GCA). Excellent CE‐MRA image quality could be achieved and even vascular geometry of small superficial cranial arteries could be successfully visualized using single dose (0.1 mmol/kg) contrast agent administration and a dedicated phased‐array head and neck coil at 3T. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.