bluuebunny/crossref_metadata_2025_split huggingface dataset:
The non‐Gaussian nature of bibliometric and scientometric distributions: A new approach to interpretation
Authors: Ivancheva Ludmila E. 
Published: August 2002

AbstractAn attempt has been made to give an answer to the question: Why do most bibliometric and scientometric laws reveal characters of Non‐Gaussian distributions, i.e., have unduly long “tails”? We tried to apply the approach of the so‐called “Universal Law,” discovered by G. Stankov (1997, 1998). The basic principle we have used here is that of the reciprocity of energy and space. A new “wave concept” of scientific information has been propounded, in which terms the well‐known bibliometric and scientometric distributions find a rather satisfactory explanation. One of the made corollaries is that α = 1 is the most reasonable value for the family of Zipf laws, applied to information or social phenomena.
Effect of naproxen co‐administration on valproate disposition
Authors: Addison R.S. , Parker‐Scott S.L. , Hooper W.D. , Eadie M.J. , Dickinson R.G. 
Published: August 2002

AbstractThe effects of co‐administration of the antiepileptic agent valproic acid (VPA) and the non‐steroidal anti‐inflammatory drug naproxen (NAP) on their relative dispositions (particularly with respect to glucuronidation) were investigated in human volunteers. Seven healthy males received each drug alone and then in combination (orally twice daily for seven days, 500 mg sodium VPA, 500 mg NAP). On day 7 of each dosing phase, serial plasma and 24 h urine samples were collected for analysis. Co‐administration of NAP resulted in significant increases (about 20%, p<0.05) in the apparent plasma clearance of total VPA and in the unbound fraction of VPA in plasma, with the apparent plasma clearance of unbound VPA being unchanged. There were associated increases in the formation clearances to urinary VPA‐glucuronide and 3‐oxo‐VPA, though these were relatively greater for the glucuronidation pathway (and remained significant when formation clearances were calculated using the unbound fraction of drug in plasma). The data thus point to a shift towards glucuronidation as a result of the NAP‐induced increase in the unbound fraction of VPA in plasma. By contrast, VPA co‐administration caused a decrease (of about 10%, p<0.05) in the apparent plasma clearance of total NAP. Taken in hand with in vitro results showing a VPA‐induced displacement (of about 40%) of NAP from plasma protein binding sites, the data strongly support a role for diminished glucuronidation of NAP and its desmethyl metabolite in the presence of co‐administered VPA. Copyright © 2000 John Wiley & Sons, Ltd.
Pharmacokinetics of lovastatin extended‐release dosage form (Lovastatin XL) in healthy volunteers
Authors: Lamson Michael , Phillips Gale , Shen Jason , Lukacsko Peter , Friedhoff Lawrence , Niecestro Robert M. 
Published: August 2002

AbstractThe purpose of this study was to evaluate pharmacokinetics and dose proportionality of lovastatin extended‐release dosage form (ER‐lovastatin) in the dosage levels of 10, 20 and 40 mg in 9 healthy male subjects. Each subject was randomized to receive a single oral dose of ER‐lovastatin either 10, 20 or 40 mg in a three‐way crossover design with a washout period of 7 days between the treatments. Subjects were served dinner at approximately 5:30 PM followed by dosing at approximately 10:00 PM in each study period. Serial plasma samples were collected up to 48 h after dosing and assayed for lovastatin and its active metabolite lovastatin acid using an LC/MS/MS method. The plasma concentration–time profiles of lovastatin and its active metabolite lovastatin acid exhibited delayed‐ and extended‐release characteristics at each dose. Mean (±) values for the Cmax of lovastatin were 1.04±0.43, 2.03±0.65 and 4.03±3.02 ng/ml for the 10, 20 and 40 mg dosage, respectively. The corresponding values for the AUC0–48 h of lovastatin were 14.6±7.8, 34.1 ±13.7, and 53.9±35.6 ng h/ml. The same tendency was also found for Cmax and AUC0−48 h values of lovastatin acid. Results from this study demonstrated as the dose of ER‐lovastatin increased from 10 to 40 mg, the Cmax and AUC0−48 h values of lovastatin as well as lovastatin acid appeared to increase linearly. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of high ELF magnetic fields on enzyme‐catalyzed DNA and RNA synthesis in vitro and on a cell‐free DNA mismatch repair
Authors: Harada Shin‐ichi , Yamada Sotoshi , Kuramata Osamu , Gunji Yoshirou , Kawasaki Masatoshi , Miyakawa Tomokazu , Yonekura Hideto , Sakurai Shigeru , Bessho Kazuo , Hosono Ryuji , Yamamoto Hiroshi 
Published: August 2002

AbstractEnvironmental electromagnetic fields have been implicated in human cancers. We examined whether high extremely low frequency (ELF) AC magnetic fields could affect DNA synthesis, transcription or repair, using in vitro model systems with defined sequences. The rate and fidelity of DNA polymerase catalyzed DNA synthesis, as well as of RNA polymerase catalyzed RNA synthesis, were not statistically significantly affected by 60 Hz 0.25–0.5 Tesla magnetic fields. The efficiency of mutS dependent mismatch repair with human cell extracts was also not affected by the magnetic field exposure. The results suggest that the core processes related to the transmission of genetic information are stable under high ELF magnetic fields. Bioelectromagnetics 22:260–266, 2001. © 2001 Wiley‐Liss, Inc.
Control of growth and organ size in Drosophila
Authors: Johnston Laura A. , Gallant Peter 
Published: August 2002

AbstractTransplantation experiments have shown that developing metazoan organs carry intrinsic information about their size and shape. Organ and body size are also sensitive to extrinsic cues provided by the environment, such as the availability of nutrients. The genetic and molecular pathways that contribute to animal size and shape are numerous, yet how they cooperate to control growth is mysterious. The recent identification and characterization of several mutations affecting growth in Drosophila melanogaster promises to provide insights. Many of these mutations affect the extrinsic control of animal size; others affect the organ‐intrinsic control of pattern and size. In this review, we summarize the characteristics of some of these mutations and their roles in growth and size control. In addition, we speculate about possible connections between the extrinsic and intrinsic pathways controlling growth and pattern. BioEssays 24:54–64, 2002. © 2002 John Wiley & Sons, Inc.
Securing genome stability by orchestrating DNA repair: removal of radiation‐induced clustered lesions in DNA
Authors: Dianov Grigory L. , O'Neill Peter , Goodhead Dudley T. 
Published: August 2002

AbstractIn addition to double‐ and single‐strand DNA breaks and isolated base modifications, ionizing radiation induces clustered DNA damage, which contains two or more lesions closely spaced within about two helical turns on opposite DNA strands. Post‐irradiation repair of single‐base lesions is routinely performed by base excision repair and a DNA strand break is involved as an intermediate. Simultaneous processing of lesions on opposite DNA strands may generate double‐strand DNA breaks and enhance nonhomologous end joining, which frequently results in the formation of deletions. Recent studies support the possibility that the mechanism of base excision repair contributes to genome stability by diminishing the formation of double‐strand DNA breaks during processing of clustered lesions. BioEssays 23:745–749, 2001. © 2001 John Wiley & Sons, Inc.
Antioxidant activity of 4‐flavonil‐1,4‐dihydropyridine derivatives
Authors: Kruk Irena , Kladna Aleksandra , Lichszteld Krzysztof , Michalska Teresa , Aboul‐Enein Hassan Y. , Tunçbilek Meral , Ertan Rahmiye 
Published: August 2002

AbstractThe effect of 4‐flavonil‐1,4‐dihydropyridine derivatives on a chemical system involving a superoxide radical anion was tested using the chemiluminescence and spectrophotometry methods. All tested compounds enhanced the light emission from the system. The obtained results indicated that the tested derivatives may catalyze the conversion of superoxide radicals, thus showing superoxide dismutase activity. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 163–167, 2001
Micro‐Raman characterization of high‐ and low‐spin heme moieties within single living erythrocytes
Authors: Wood Bayden R. , McNaughton Don 
Published: August 2002

AbstractRaman microspectroscopy was applied to monitor porphyrin perturbation associated with the tense‐relaxed (T → R) state transition of hemoglobin (Hb) within a single red blood cell. The spectra exhibited dramatic changes in the spin state region (1650–1500 cm−1) and the methine CH deformation region (1250–1200 cm−1) between the 27‐ and 54‐min interval following reoxygenation. Principal components analysis revealed a sigmoidal curve when the PC1 scores versus time were plotted. The inflection point on the curve corresponded to the T → R transition point spectrum, indicating the cell is composed of Hb in a mixture of spin states. The results of this work illustrate the dynamics of porphyrin perturbation during erythrocyte respiration and may have applications in the diagnosis and treatment of red blood cell disorders including thalassemia and sickle cell anemia. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 259–262, 2002
Ordering in aqueous polysaccharide solutions. II. Optical rotation and heat capacity of aqueous solutions of a triple‐helical polysaccharide schizophyllan*
Authors: Yoshiba Kazuto , Ishino Tetsurou , Teramoto Akio , Nakamura Naotake , Miyazaki Yuji , Sorai Michio , Wang Qi , Hayashi Yoshihito , Shinyashiki Naoki , Yagihara Shin 
Published: August 2002

AbstractDeuterium oxide solutions of schizophyllan, a triple‐helical polysaccharide, undergoing an order–disorder transition centered at 17°C, were studied by optical rotation (OR) and heat capacity (Cp) to elucidate the molecular mechanism of the transition and water structure in the solution and frozen states. The ordered structure at low temperature consisted of the side chains and water in the vicinity forming an ordered hydrogen‐bonded network surrounding the helix core and was disordered at higher temperature. In the solution state appeared clearly defined transition curves in both the OR and Cp data. The results for three samples of different molecular weights were analyzed theoretically, treating this transition as a typical linear cooperative transition from the ordered to disordered states and explained quantitatively if the molecular weight polydispersity of the sample was considered. The excess heat capacity C defined as the Cp minus the contributions from schizophyllan and D2O was estimated. In the frozen state it increased with raising temperature above 150 K until the mixture melted. This was compared with the dielectric increment observed in this temperature range and ascribed to unfreezable water. From the heat capacity and dielectric data, unfreezable water is mobile but more ordered than free water. In the solution state, the excess heat capacity originates from the interactions of D2O molecules as bound water and structured water, and so forth. Thus the schizophyllan triple helix molds water into various structures of differing orders in solution and in the solid state. © 2002 Wiley Periodicals, Inc. Biopolymers 63: 370–381, 2002
The effect of ethanol on the kinetics of lipase‐mediated enantioselective esterification of 4‐methyloctanoic acid and the hydrolysis of its ethyl ester
Authors: Heinsman Nicole W. J. T. , Valente Ana M. , Smienk Henry G. F. , van der Padt Albert , Franssen Maurice C. R. , de Groot Aede , van ‘t Riet Klaas 
Published: August 2002

AbstractThe Novozym 435® catalyzed esterification and hydrolysis reactions of 4‐methyloctanoic acid (ethyl ester) were investigated. In both the hydrolysis and esterification reactions, the increase of ethanol concentration led to an increase in enantiomeric ratio (E). For hydrolysis of the ethyl ester, the E‐value increased from 5.5 [0% (v/v) EtOH] up to 12 [20% (v/v) EtOH]. In case of esterification, the E‐value was already 16 [14% (v/v) EtOH] and rose to 57 [73% (v/v) EtOH]. When combining these results of esterification and hydrolysis, an enantiomeric ratio of 350 can be estimated for the sequential kinetic resolution of 4‐methyloctanoic acid. In this way, enantiopure 4‐methyloctanoic acid could be obtained after two consecutive reaction steps. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 193–199, 2001.
On‐line stoichiometry and identification of metabolic state under dynamic process conditions
Authors: Herwig Christoph , Marison Ian , von Stockar Urs 
Published: August 2002

AbstractA method for the on‐line calculation of conversion rates and yield coefficients under dynamic process conditions was developed. The method is based on cumulated mass balances using a moving average method. Elemental balances were used to test the measured cumulated quantities for gross errors and inappropriate stoichiometry definition followed by data reconciliation and estimation of non‐measured conversion rates, using a bioprocess set‐up including multiple on‐line analysis techniques. The quantitative potential of the proposed method is demonstrated by executing transient experiments in aerobic cultures of Saccharomyces cerevisiae on glucose. Rates and yield coefficients could be consistently quantified in shift‐up, shift‐down, and accelerostat experiments. The method shows the capability to describe quantitatively transient changes in metabolism including uncoupling of catabolism and anabolism, also for the case when multiple components of metabolism are not measured. The validity of the experiment can be evaluated on‐line. Additionally, the method detects with high sensitivity inappropriate stoichiometry definition, such as a change in state of metabolism. It was shown that concentration values can be misleading for the identification of the metabolic state. In contrast, the proposed method provides a clear picture of the metabolic state and new physiological regulations could be revealed. Hence, the novelty of the proposed method is the on‐line availability of consistent stoichiometric coefficients allowing a significant speed up in strain characterization and bioprocess development using minimal knowledge of the metabolism. Additionally, it opens up the use of transient experiments for physiological studies. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 345–354, 2001.
Further studies on the contribution of electrostatic and hydrophobic interactions to protein adsorption on dye–ligand adsorbents
Authors: Zhang Songping , Sun Yan 
Published: August 2002

AbstractThe adsorption equilibria of bovine serum albumin (BSA), γ‐globulin, and lysozyme to three kinds of Cibacron blue 3GA (CB)‐modified agarose gels, 6% agarose gel‐coated steel heads (6AS), Sepharose CL‐6B, and a home‐made 4% agarose gel (4AB), were studied. We show that ionic strength has irregular effects on BSA adsorption to the CB‐modified affinity gels by affecting the interactions between the negatively charged protein and CB as well as CB and the support matrix. At low salt concentrations, the increase in ionic strength decreases the electrostatic repulsion between negatively charged BSA and the negatively charged gel surfaces, thus resulting in the increase of BSA adsorption. This tendency depends on the pore size of the solid matrix, CB coupling density, and the net negative charges of proteins (or aqueous ‐ phase pH value). Sepharose gel has larger average pore size, so the electrostatic repulsion‐effected protein exclusion from the small gel pores is observed only for the affinity adsorbent with high CB coupling density (15.4 μmol/mL) at very low ionic strength (NaCl concentration below 0.05 M in 10 mM Tris‐HCl buffer, pH 7.5). However, because CB–6AS and CB–4AB have a smaller pore size, the electrostatic exclusion effect can be found at NaCl concentrations of up to 0.2 M. The electrostatic exclusion effect is even found for CB–6AS with a CB density as low as 2.38 μmol/mL. Moreover, the electrostatic exclusion effect decreases with decreasing aqueous‐phase pH due to the decrease of the net negative charges of the protein. For γ‐globulin and lysozyme with higher isoelectric points than BSA, the electrostatic exclusion effect is not observed. At higher ionic strength, protein adsorption to the CB‐modified adsorbents decreases with increasing ionic strength. It is concluded that the hydrophobic interaction between CB molecules and the support matrix increases with increasing ionic strength, leading to the decrease of ligand density accessible to proteins, and then the decrease of protein adsorption. Thus, due to the hybrid effect of electrostatic and hydrophobic interactions, in most cases studied there exists a salt concentration to maximize BSA adsorption. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 710–717, 2001.
Reactivity and stability of mycelium‐bound carboxylesterase from Aspergillus oryzae
Authors: Converti Attilio , Borghi Adriana Del , Gandolfi Raffaella , Lodi Alessandra , Molinari Francesco , Palazzi Emilio 
Published: August 2002

AbstractThe reactivity and thermostability of a novel mycelium‐bound carboxylesterase from lyophilized cells of Aspergillus oryzae are explored in organic solvent. Ethanol acetylation was selected as reference esterification reaction. High carboxylesterase activity cells were used as biocatalyst in batch esterification tests at 12.5 < So < 125 mmol L−1, 5.0 < Xo < 30 g L−1, 0.49 < log P < 4.5 and 30 < T < 80°C, as well as in residual activity tests after incubation at 40 < T < 90°C. The starting rates of product formation were used to estimate with the Arrhenius model the apparent activation enthalpies of the enzymatic reaction (29–33 kJ mol−1), the reversible unfolding (56–63 kJ mol−1), and the irreversible denaturation (22 kJ mol−1) of the biocatalyst. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 232–237, 2002.
Production of different morphologies of biocompatible polymeric materials by supercritical CO2 antisolvent techniques
Authors: Elvassore Nicola , Baggio Marco , Pallado Paolo , Bertucco Alberto 
Published: August 2002

AbstractHigh‐value biocompatible‐polymers have been processed with supercritical antisolvent techniques to produce solid structures of different shape and size. In particular, a class of hyaluronic acid‐derived polymers (Hyaff11‐p100, Hyaff11‐p80, Hyaff11‐p75, Hyaff 302) have been used to obtain various morphologies such as microspheres, threads, fibers, networks, and sponges. The effect of thermodynamic variables on precipitation were highlighted in some preliminary batch experiments. Then, different products were obtained by tuning the values of operating parameters. Threads and fibers were the result of a continuous supercritical antisolvent (SAS) process where a concentrated polymer solution was pumped through a micrometric nozzle: The threads showed a reticular internal structure with an adjustable type of cavity. For production of networks and sponges, the concentration of polymer plays the key role. Below a critical value it was not possible to obtain a continuous network, while above it, a structure similar to that of the natural bone with three types of internal microporosity were obtained. Again, by tuning pressure and polymer concentration, the internal porosity could be controlled. Microparticles were also produced by the SAS process, and a control of their morphology was achieved by varying the concentration of the polymer in the starting solution and the density of organic solvent‐CO2 mixtures. All the products obtained by SAS have negligible content of residual solvent. A qualitative interpretation of experimental results is presented. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 449–457, 2001.
DegP‐coexpression minimizes inclusion‐body formation upon overproduction of recombinant penicillin acylase in Escherichia coli
Authors: Lin Wen‐Jer , Huang Shin‐Wei , Chou C. Perry 
Published: August 2002

AbstractWe demonstrated the enhancement of recombinant penicillin acylase (PAC) production in Escherichia coli by increasing the intracellular concentration of the periplasmic protease DegP. Using appropriate host/vector systems (e.g., HB101 harboring pTrcKnPAC2902 or MDΔP7 harboring pTrcKnPAC2902) in which the expression of the pac gene was regulated by the strong trc promoter, the overproduction of PAC was often limited by periplasmic processing and inclusion bodies composed of protein aggregates of PAC precursors were formed in the periplasm. The amount of these periplasmic inclusion bodies was significantly reduced and PAC activity was significantly increased upon coexpression of DegP. The specific PAC activity reached an extremely high level of 674 U/L/OD600 for MDΔP7 harboring pTrcKnPAC2902 and pKS12 under optimum culture conditions. However, such improvement in the production of PAC was not observed for the expression systems (e.g., MDΔP7 harboring pCLL2902) in which the periplasmic processing was not the step limiting the production of PAC. The results suggest that DegP could in vivo assist the periplasmic processing though the enzyme is shown to be not absolutely required for the formation of active PAC in E. coli. In addition, the steps limiting the production of PAC are identified and the reasons for the formation of PAC inclusion bodies are discussed here. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 484–492, 2001.
Bromoperoxidase activity in microplantlet suspension cultures of the macrophytic red alga Ochtodes secundiramea
Authors: Rorrer Gregory L. , Tucker Mary P. , Cheney Donald P. , Maliakal Sanjiv 
Published: August 2002

AbstractBromoperoxidase is an enzyme found in marine macroalgae that catalyzes the bromination of organic substrates. Photosynthetic microplantlet suspension cultures derived from the macrophytic red alga Ochtodes secundiramea were shown to possess bromoperoxidase. The optimum pH for O. secundiramea bromoperoxidase activity in cell‐free extracts was 6.0, and the half‐saturation constant for bromination of the exogeneous substrate monochlorodimedone (MCD) was 18 μM. O. secundiramea microplantlets were cultivated in a bubble‐column photobioreactor at an incident light intensity of 38 μE m−2 s−1 (71% of light‐saturated photosynthesis, 10:14 light:dark photoperiod), and the kinetics of cell growth and bromoperoxidase production were followed. At these conditions, the specific growth rate was 0.052 day−1. The lowest specific bromoperoxidase activity of 0.3 μmol MCD g−1 cell min−1 occurred during the midexponential phase of growth, and then increased steeply to 1.9 μmol MCD g−1 cell min−1 during the late stationary phase, suggesting that bromoperoxidase production was part of secondary metabolism. The estimated bromoperoxidase content in the cell mass at late stationary phase was 67 μg g−1 dry cell mass, demonstrating that bioreactor production of marine bromoperoxidase is feasible. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 389–395, 2001.