bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capacitively coupled contactless conductivity detection in capillary electrophoresis
Authors: Zemann Andreas J. 
Published: July 2003

AbstractCapacitively coupled contactless conductivity detection (C4D) has become an accepted detection method in capillary electrophoresis (CE) for a variety of analytes. Advantages of this technique over optical detection modes and galvanic contact conductivity detection include great flexibility in capillary handling and rather simple mechanical parts and electronics, as it can be performed in an on‐capillary mode. Furthermore, the detection principle can be used with capillaries made of other materials than fused silica (PEEK®, Teflon®), with chip‐based separation technologies, or with capillaries having very small inner diameters. This review presents a discussion of the published literature on C4D for CE and capillary electrochromatography.
Fed‐Batch Process for Pyruvate Production by Recombinant Escherichia coli YYC202 Strain
Authors: Zelić B. , Gerharz T. , Bott M. , Vasić‐Rački Đ. , Wandrey C. , Takors R. 
Published: July 2003

AbstractFed‐batch fermentation was applied to the production of pyruvate by using a recombinant Escherichia coli YYC202 strain. This strain is completely blocked in its ability to convert pyruvate into acetyl‐CoA or acetate, resulting in acetate auxotrophy during growth in glucose minimal medium. By controlling acetate and glucose feed rate, a series of lab‐scale fed‐batch experiments were performed at pH 7 and 37 °C. CO2 production rate (CTR) was used for on‐line regulation of the acetate feed rate. The correlation between CTR and acetate consumption rate (ACR) was determined experimentally. At optimal process conditions a final pyruvate concentration higher than 62 g/L, a space‐time yield of up to 42 g/L/d and pyruvate/glucose molar yield of 1.11 mol/mol were achieved. Experimental evidence was gathered that pyruvate export is active.
On detrending and cyclical asymmetry
Authors: Psaradakis Zacharias , Sola Martin 
Published: June 2003

AbstractThis paper considers the issue of testing for symmetry of the business cycle. It is demonstrated that findings of symmetry should be interpreted with caution since tests tend to have low power to detect asymmetries when applied to data that have been filtered to isolate their stationary business‐cycle component. This implies that asymmetries are likely to be detected in practice only when they are particularly prominent. An empirical application examines the properties of the cyclical component of real GDP for the G7 countries. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of water‐miscible solvents on the organic solvent‐resistant tyrosinase from Streptomyces sp. REN‐21
Authors: Rodakiewicz‐Nowak Janina , Ito Masaaki 
Published: June 2003

AbstractThe effect of various water‐miscible organic solvents (ethanol, methanol, acetone, acetonitrile, N,N‐dimethylformamide (DMF) and dimethylsulfoxide (DMSO)) on the kinetics of 4‐tert‐butylcatechol (tBC) oxidation in the presence of different samples of organic solvent‐resistant tyrosinase (OSRT) has been studied. In contrast to mushroom tyrosinase the enzyme shows a high relative stability in solutions of organic solvents and increased activity toward the bulky and hydrophobic substrate, tBC, in respect to catechol. Rates of the studied OSRT‐catalyzed reactions are however reduced by the presence of organic solvents and for all studied samples of OSRT decrease exponentially with the content of an organic solvent. The effect has been satisfactorily described by the effect of organic solvents on the thermodynamic activity of tBC. The correlation of the inhibition parameters with the hydrophobicity of a particular solvent (log P), its intrinsic molar volume, Vi, and the Dimroth–Reichardt parameter, ET(30), are shown. The results allow also the prediction of OSRT activity in aqueous solutions of water‐miscible organic solvents. Copyright © 2003 Society of Chemical Industry
Process kinetics of UASB reactors treating non‐inhibitory substrate
Authors: Huang Ju‐Sheng , Jih Charng‐Gwo , Lin Shin‐Dow , Ting Wen‐Huei 
Published: June 2003

AbstractThe degradation of a non‐inhibitory substrate (sucrose) in upflow anaerobic sludge bed (UASB) reactors with different superficial flow velocites (us) was performed to generate experimental data. Additionally, a kinetic model accounting for the mass fraction of methanogens (f) and granule size distribution in UASB reactors is also proposed. At the volumetric loadings of 2.65–21.16 g COD dm−3 day−1, both the COD removal efficiency and granule size of the UASB reactors increase with increasing us. The f values determined experimentally increase from 0.13–0.24 to 0.27–0.43 if the volumetric loading is increased from 2.65 to 5.29 g COD dm−3 day−1. With a further increase in volumetric loading, the f values decline because of the accumulation of volatile fatty acids (VFAs). The predicted residual concentrations of VFAs and COD are in fairly good agreement with the experimental data. From the calculated effectiveness‐factor values, the influence of mass transfer resistance of the substrate sucrose on the overall substrate removal rate should not be neglected. From parametric sensitivity analyses together with the simulated concentration profiles, methanogenesis is the rate‐limiting step. Copyright © 2003 Society of Chemical Industry
Conformational restrictions in the active site of unliganded human caspase‐3
Authors: Ni Chao‐Zhou , Li Chenglong , Wu Joe C. , Spada Alfred P. , Ely Kathryn R. 
Published: June 2003

AbstractCaspases are cysteine proteases that play a critical role in the initiation and regulation of apoptosis. These enzymes act in a cascade to promote cell death through proteolytic cleavage of intracellular proteins. Since activation of apoptosis is implicated in human diseases such as cancer and neurodegenerative disorders, caspases are targets for drugs designed to modulate their action. Active caspases are heterodimeric enzymes with two symmetrically arranged active sites at opposite ends of the molecule. A number of crystal structures of caspases with peptides or proteins bound at the active sites have defined the mechanism of action of these enzymes, but molecular information about the active sites before substrate engagement has been lacking. As part of a study of peptidyl inhibitors of caspase‐3, we crystallized a complex where the inhibitor did not bind in the active site. Here we present the crystal structure of the unoccupied substrate‐binding site of caspase‐3. No large conformational differences were apparent when this site was compared with that in enzyme‐inhibitor complexes. Instead, the 1.9 Å structure reveals critical side chain movements in a hydrophobic pocket in the active site. Notably, the side chain of tyrosine204 is rotated by ∼90° so that the phenol group occupies the S2 subsite in the active site. Thus, binding of substrate or inhibitors is impeded unless rotation of this side chain opens the area. The positions of these side chains may have important implications for the directed design of inhibitors of caspase‐3 or caspase‐7. Copyright © 2003 John Wiley & Sons, Ltd.
Reexamination of the recognition preference of the specificity pocket of the Abl SH3 domain
Authors: Santamaria Fanny , Wu Zhibin , Boulègue Cyril , Pál Gábor , Lu Wuyuan 
Published: June 2003

AbstractSrc homology‐3 (SH3) domains mediate important protein–protein interactions in a variety of normal and pathological cellular processes, thus providing an attractive target for the selective interference of SH3‐dependent signaling events that govern these processes. Most SH3 domains recognize proline‐rich peptides with low affinity and poor selectivity, and the goal to design potent and specific ligands for various SH3 domains remains elusive. Better understanding of the molecular basis for SH3 domain recognition is needed in order to design such ligands with potency and specificity. In this report, we seek to define a clear recognition preference of the specificity pocket of the Abl SH3 domain using targeted synthetic peptide libraries. High‐resolution affinity panning coupled with mass spectrometric readout allows for quick identification of Trp as the preferred fourth residue in the decapeptide ligand APTWSPPPPP, which binds to Abl SH3 four times stronger than does the decapeptide containing Tyr or Phe in the fourth position. This finding is in contrast to several reports that Tyr is the only residue selected from phage displayed peptide libraries that interacts with the specificity pocket of Abl SH3. This simple, unbiased approach can fine‐tune the affinity and selectivity of both natural and unnatural SH3 ligands whose consensus binding sequence has been pre‐defined by combinatorial library methods. Copyright © 2003 John Wiley & Sons, Ltd.
Influence of microbial activity and soil moisture on herbicide immobilization in soils
Authors: Pätzold Stefan , Brümmer Gerhard W. 
Published: June 2003

AbstractMobility, extractability, and disappearance of the herbicides diuron, terbuthylazine, metolachlor, and pendimethalin were examined in incubation experiments with two topsoil samples of different natural microbial activity and after sterilization. Soil moisture was held constant at 10, 40, and 60 % WHC. In other variants, the soil water content was changed during the incubation.The four herbicides reveal a fairly different extent of microbial and chemical degradation and immobilization. The herbicide mobility – expressed by coefficients of partition between adsorbed and dissolved herbicide amounts – decreases at a lower rate and extent, when the microbial activity is low or the soil is sterile. With increasing initial soil moisture, also herbicide mobility and extractability increase; but in the course of time, abiotic immobilization occurs to a higher extent. When soil moisture changes during the incubation, formerly non‐extractable herbicide fractions (up to 40 % of the applied amounts) become extractable.Kinetics of herbicide immobilization follow an empirical sigmoidal function, which describes three periods of immobilization. The three‐period shape of the curve and its possible reasons are discussed for the data of the incubation experiments as well as for the results of a long‐term field trial with diuron.
Erfassung der Variabilität von Bodenmerkmalen in einem Blindversuch auf Fahlerde mittels Methoden der räumlichen Statistik
Authors: Kuzyakova Irina , Richter Christel 
Published: June 2003

AbstractMittels Kopplung der Methoden der klassischen Statistik und der Geostatistik wurden für einen Blindversuch auf Fahlerde die Zusammenhänge zwischen den Bodenmerkmalen Gesamtkohlenstoffgehalt (Ct), Gehalt an Feinerde (FAT = Ton+Feinschluff [%]), pflanzenverfügbarem K und P (mg (100g Boden)–1), pHKCl‐Werten im Ober‐ (0 – 30 cm) und Unterboden (31 – 40 cm) und bodenbildenden Faktoren (Tiefe der Lehmunterlagerung und Mikrorelief) untersucht.Die Glättung der Rohdaten mittels Block‐Kriging führte zur Eliminierung der kleinräumigen Komponente der Variabilität. Dadurch stiegen die Rangkorrelationskoeffizienten zwischen den Bodenmerkmalen bis auf das 2‐fache an und erreichten im Oberboden –0, 52 für Ct–FAT; 0, 69 für Ct–K und 0, 55 für Ct–P. Signifikante Korrelationen, Ähnlichkeit der Karten und der Variogramme ließen schlussfolgern, dass die räumliche Verteilung von FAT, Ct, K und P im Oberboden durch gemeinsame Faktoren bedingt ist. Als wichtigste variabilitätsverursachende Faktoren der Bodeneigenschaften ergaben sich die Tiefe der Lehmunterlagerung und das Relief. Die Rangkorrelationskoeffizienten der geglätteten trendbereinigten Nivellementwerte mit den Merkmalen FAT, Ct, K und P im Oberboden betrugen –0, 63; –0, 77; –0, 71 und –0, 57.
Soil properties, but not plant nutrients (N, P, K) interact with chemically induced resistance against powdery mildew in barley
Authors: Wiese Joachim , Bagy Magdy M. K. , Schubert Sven 
Published: June 2003

AbstractChemically induced resistance is a promising method of plant protection against diseases, which can be triggered by systemically acting chemical inducers such as BTH (benzo(1, 2, 3)thiadiazole‐carbothioic‐acid‐S‐methylester). BTH is commercially distributed as a 50 % formulation, called Bion®. The uncertain success of Bion® application in controlling infection by powdery mildew is a major obstacle in using induced resistance for plant protection in agriculture. This study aimed to investigate the effect of soil properties, selected macronutrients (N, P, and K), and addition of organic matter on induced resistance and to identify possible factors responsible for the high variability of BTH effect under field conditions. A pot experiment under open‐air conditions was set up using the pathosystem Hordeum vulgare cv. Ingrid / Blumeria graminis f. sp. hordei race A6. The different soils strongly affected the resistance of barley plants against powdery mildew after BTH treatment. The infection of barley by powdery mildew was lower than on all other soils when grown on an acid forest soil which was limed up to pH 4.9, even after BTH treatment. A reproducible induction of pathogen resistance by BTH was shown only on a mineral soil (Kleinlinden) with a negligible C content. Application of N, P, and K did not consistently affect the induction of resistance by BTH. The addition of green manure and compost led to an enhanced variability of resistance induction on the soil “Kleinlinden”. Possible effects of soil microflora on resistance induction are discussed.
Modulating effects of L‐arginine on cytokine‐stimulated lymphocyte migration in vitro
Authors: Scott Isenberg J. 
Published: June 2003

AbstractElective microsurgical transplants have become routine. Yet there remains a 1–5% rate of complete flap necrosis among these surgical reconstructions. This rate is much higher in emergent replantations. Despite technically accurate surgery, perfusion fails in this group. This lack of perfusion, or no‐reflow, has been attributed to ischemic‐reperfusion injury. The exact nature of this phenomenon remains poorly characterized, though it is clear that significant changes occur in such situations at the endothelial vascular interface. In an effort to understand the biomolecular events involved in ischemic‐reperfusion injury we investigated the modulation of leukocyte transendothelial migration. Using a chemotactic chamber model with a cytokine stimulate mono‐layer of umbilical vein endothelium, we evaluated the migration rate of peripheral blood mononuclear cells in the presence of exogenous L‐arginine and/or the nitric oxide synthase inhibitor L‐NAME. Levels of INF‐γ and TNF‐α production were also determined. It was found that in the face of cytokine pre‐stimulation and L‐arginine, mononuclear cell trans‐endothelial migration increased dramatically. There were also parallel increases in inflammatory cytokine output. These responses were sharply decreased by L‐NAME. The results of this study suggest that in vitro nitric oxide augments transendothelial migration of inflammatory cells. Modulation of this response may provide a clinically useful method of minimizing ischemic‐reperfusion injury. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:262–267 2003
Free flaps for type III complex pharyngoesophageal defects after enlarged ablative surgery for advanced cancer of larynx and hypopharynx
Authors: Antohi Nicolae , Tibirna Gheorghe , Suharski Ilie , Bejan Anatol , Marina Sergiu , Pogonet Vadim , Stan Vitalie 
Published: June 2003

AbstractFree tissue transfer has become a useful technique for reconstruction of type III complex pharyngoesophageal defects after enlarged laryngectomy and partial or total pharyngoesophageal resection. We present a retrospective analysis of our experience with 36 patients who received free flaps for reconstruction of complex pharyngoesophageal defects associated with skin and soft‐tissue defects. Free fasciocutaneous flaps and jejunum combined with a deltopectoral flap and musculocutaneous pectoralis major flap, gastro‐omental flap, and combined latissimus dorsi musculocutaneous and cutaneous scapular flaps were used for reconstruction. Adjuvant therapy included preoperative or postoperative radiotherapy. Free flap failure occurred in 2 of 36 patients. Twenty‐eight patients had good swallowing function. Better results with fewer complications in reconstruction of type III complex pharyngoesophageal defects were obtained with the use of a combined latissimus dorsi and scapular flap. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:189–193 2003
New polysaccharide‐g‐polyacrylonitrile copolymers: synthesis and thermal characterization
Authors: Zohuriaan‐Mehr M. J. , Pourjavadi A. 
Published: June 2003

AbstractVarious natural and modified polysaccharides (i.e. arabic gum, tragacanth gum, xanthan gum, sodium alginate, chitosan, sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose) were modified using ceric‐initiated graft polymerization of acrylonitrile under inert atmosphere. Grafting was confirmed using spectral (FT‐IR) proofs. The grafting parameters were determined by conventional methods. Thermal characteristics of the homopolymer‐free copolymers were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under nitrogen atmosphere. The major thermal transitions as well as the activation energy of the major decomposition stages were investigated. The polyacrylonitrile (PAN)‐grafted polysaccharides were recognized to be thermally stable more than the corresponding non‐grafted substrates, although they begin to decompose at relatively lower temperatures than the non‐grafted counterparts. Copyright © 2003 John Wiley & Sons, Ltd.
Unusual rheology behaviour of ultra high molecular weight polyethylene/kaolin composites prepared via polymerization‐filling
Authors: Wang Xin , Wu Qiye , Qi Zongneng 
Published: June 2003

AbstractThe rheological behaviour of ultra high molecular weight polyethylene (UHMWPE)/Kaolin composites prepared by a polymerization‐filling process was investigated by conducting capillary and dynamic rheology tests. The results showed that the addition of Kaolin could significantly improve the processability of UHMWPE composites. The common viscoelastic flow was discovered for UHMWPE composites in capillary extrusion testing. The further discussion showed that the unique microstructure provided by polymerization‐filling of UHMWPE/Kaolin composites led to this unusual rheology behaviour. Copyright © 2003 Society of Chemical Industry
The effect of initiator‐to‐monomer ratio on the properties of the polybutadiene‐ol synthesized by free radical solution polymerization of 1,3‐butadiene
Authors: Mohamad Sadeghi Gity Mir , Morshedian Jalil , Barikani Mehdi 
Published: June 2003

AbstractPolybutadiene‐ol was synthesized by solution radical polymerization of 1,3‐butadiene in the presence of hydrogen peroxide as initiator and 2‐propanol as solvent. The ratio of initiator to monomer molar concentration, [I0]/[M0], was varied while temperature, reaction time and the type and amount of solvent were kept constant. The effects on the Mn; Mw; Mv; PDI, OH‐number and functionality of the synthesized polyols were studied. By taking several samples during a polymerization batch and analyzing them, the time of reaction was chosen as 100 min, after which the PDI changed dramatically. Mn decreased exponentially with increasing [I0]/[M0] according to the relationship Mn = 565.55 ([I0]/[M0])−0.7553. The decrease observed in Mw gradually levelled off with increasing [I0]/[M0] and molecular weight distribution broadened at larger values of [I0]/[M0]. The OH‐number increases with [I0]/[M0]. In addition to the number‐average molecular weight, functionality is dependent on the number of hydroxyl‐terminated chain radicals in the reaction medium. Copyright © 2003 Society of Chemical Industry
Electrical properties of macromolecular complexes of coordinated polymers with mixed valence of Co(II), Co(III) and Co(II–III)
Authors: Elghanem HM , Jawad S Abdul , Aljundi J , Afaneh F , Arafa I 
Published: June 2003

AbstractElectrical properties of bis‐ethylenediamine Co(II), Co(III) and Co(II–III) mixed valence complexes and polyethylenediaminecarbosilazane (PEDCSZ) [Co(II), Co(III) and Co(II–III)] macromolecules were measured at room temperature in a frequency range between 1 Hz and 106 Hz. Electrical modulus, permittivity and ac conductivity were calculated using ac impedance and phase‐angle measurements. It was found that the overall conductivity of PEDCSZ macromolecules with Co is much higher than that for Co monomers. In addition, the conductivity of PEDCSZ Co(III) and Co(II–III) mixed valence compounds are higher than those containing Co(II) where the electronic conduction is dominant. The relaxation time increases from about 2.7 × 10−6 s for Co(II) chloride to a value of 2.9 × 10−4 s for Co(II–III) chloride monomers. Copyright © 2003 Society of Chemical Industry
Synthesis and characterization of novel aromatic poly(amide‐imide)s derived from 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl or 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl and various aromatic diamines
Authors: Banihashemi Ahmad , Behniafar Hossein 
Published: June 2003

AbstractNew aromatic diimide‐dicarboxylic acids having kinked and cranked structures, 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl (2a) and 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl (2b), were synthesized by the reaction of trimellitic anhydride with 2,2′‐bis(4‐aminophenoxy)biphenyl (1a) and 2,2′‐bis(4‐aminophenoxy)‐1,1′‐binaphthyl (1b), respectively. Compounds 2a and 2b were characterized by FT‐IR and NMR spectroscopy and elemental analyses. Then, a series of novel aromatic poly(amide‐imide)s were prepared by the phosphorylation polycondensation of the synthesized monomers with various aromatic diamines. Owing to structural similarity, and a comparison of the characterization data, a model compound was synthesized by the reaction of 2b with aniline. The resulting polymers with inherent viscosities of 0.58–0.97 dl g−1 were obtained in high yield. The polymers were fully characterized by FT‐IR and NMR spectroscopy. The ultraviolet λmax values of the poly(amide‐imide)s were also determined. The polymers were readily soluble in polar aprotic solvents. They exhibited excellent thermal stabilities and had 10% weight loss at temperatures above 500 °C under a nitrogen atmosphere. Copyright © 2003 Society of Chemical Industry
DNA adsorption on a poly‐L‐lysine‐immobilized poly(2‐hydroxyethyl methacrylate) membrane
Authors: Şenel Serap , Bayramoǧlu Gülay , Arıca M Yakup 
Published: June 2003

AbstractThe DNA adsorption properties of poly‐L‐lysine‐immobilized poly(2‐hydroxyethyl methacrylate) (pHEMA) membrane were investigated. The pHEMA membrane was prepared by UV‐initiated photopolymerization and activated with epichlorohydrin. Poly‐L‐lysine was then immobilized on the activated pHEMA membrane by covalent bonding, via a direct chemical reaction between the amino group of poly‐L‐lysine and the epoxy group of pHEMA. The poly‐L‐lysine content of the membrane was determined as 1537 mg m−2. The poly‐L‐lysine‐immobilized membrane was utilized as an adsorbent in DNA adsorption experiments. The maximum adsorption of DNA on the poly‐L‐lysine‐immobilized pHEMA membrane was observed at 4 °C from phosphate‐buffered salt solution (pH 7.4, 0.1 M; NaCl 0.5 M) containing different amounts of DNA. The non‐specific adsorption of DNA on the plain pHEMA membrane was low (about 263 mg m−2). Higher DNA adsorption values (up to 5849 mg m−2) were obtained in which the poly‐L‐lysine‐immobilized pHEMA membrane was used. Copyright © 2003 Society of Chemical Industry