bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of nonionic surfactants on the UV/visible absorption of bacterial cells
Authors: Brown Derick G. , Jaffé Peter R. 
Published: September 2002

AbstractNonionic surfactants are used in a number of different microbiological applications, including solubilization of cell membranes, washing bacterial cultures prior to experimentation, and enhancing biodegradation of low‐solubility compounds. An important consideration in these applications is the potential for the surfactant to alter the cell membrane. One potential means to monitor the impact of surfactants on the bacterial cell membrane is through monitoring the absorbance spectrum of the bacterial suspension. This is due to the colloidal nature of bacteria, where the absorbance of a bacterial suspension is related to the size and refractive index of the bacterial cells. Through a systematic study it was shown that there can be a significant change in the bacterial absorbance spectrum due to the presence of nonionic surfactants, with the effect a function of surfactant structure and concentration, solution ionic strength and cation valence. The effects were most pronounced with Na+ as the cation, with surfactants having mid‐range hydrophile‐lipophile balance (HLB) values, and with surfactant concentrations above the CMC. The results indicate that measurement of the absorbance spectrum of bacterial cultures can provide a means to monitor the effects of nonionic surfactants on the bacterial cell membrane. In addition, depending on the specific application, appropriate selection of surfactant structure and media composition can be made to enhance or minimize the effects. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 476–482, 2001.
High‐level expression and stabilization of recombinant human chitinase produced in a continuous constitutive Pichia pastoris expression system
Authors: Goodrick J. C. , Xu M. , Finnegan R. , Schilling B. M. , Schiavi S. , Hoppe H. , Wan N. C. 
Published: September 2002

AbstractA continuous fermentation process has been developed in Pichia pastoris (P. pastoris) with the glyceraldehyde‐3‐phosphate dehydrogenase (GAP) promoter in order to produce large quantities of recombinant human chitinase (rh‐chitinase) for preclinical studies as a potential high‐dose antifungal drug. Expression levels of about 200 to 400 mg/L have been demonstrated in fed‐batch fermentations using strains with either the traditional methanol‐inducible or the constitutive GAP promoter. Proteolytic degradation of the enzyme was typically seen in fed‐batch fermentations. Continuous production of the enzyme by P. pastoris with the GAP promoter was demonstrated in a 1.5‐L working volume fermentor using either glucose or glycerol as the carbon source. The fermentation could be extended for >1 month with a steady‐state protein concentration of approximately 300 mg/L. Cell densities were >400 g/L wet cell weight (WCW) (approximately 100 g/L dry cell weight [DCW]) at a dilution rate (D) of 0.83 day−1 or 1.2 volume exchanges per day (VVD). No proteolytic degradation of the enzyme was seen in the continuous fermentation mode. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 492–497, 2001.
Factors affecting α,‐1,2 glucooligosaccharide synthesis by Leuconostoc mesenteroides NRRL B‐1299 dextransucrase
Authors: Dols‐Lafargue Marguerite , Willemot René‐Marc , Monsan Pierre F. , Remaud‐Simeon Magali 
Published: September 2002

AbstractThe optimization of α‐1,2 glucooligosaccharide (GOS) synthesis from maltose and sucrose by Leuconostoc mesenteroides NRRL B‐1299 dextransucrase was achieved using experimental design and consecutive analysis of the key parameters. An increase of the pH of the reaction from 5.4 to 6.7 and of the temperature from 25 to 40°C significantly favored α‐1,2 GOS synthesis, thanks to a significant decrease of the side reactions, i.e., dextran and leucrose synthesis. These positive effects were not sufficient to compensate for the decrease of enzyme stability caused by the use of high pH and temperature. However, the critical parameters were the sucrose to maltose concentration ratio (S/M) and the total sugar concentration (TSC). α1,2 GOS synthesis was favored at high S/M ratios. But using these conditions also led to an increase of side reactions which could be modulated by choosing the appropriate TSC. Finally, with S/M = 4 and TSC = 45% w/v, dextran and leucrose productions were limited and the final α‐1,2 GOS yield reached 56.7%, the total GOS yield being 88%. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 498–504, 2001.
A priori analysis of metabolic flux identifiability from 13C‐labeling data
Authors: van Winden Wouter A. , Heijnen Joseph J. , Verheijen Peter J. T. , Grievink Johan 
Published: September 2002

AbstractThe 13C‐labeling technique was introduced in the field of metabolic engineering as a tool for determining fluxes that could not be found using the ‘classical’ method of flux balancing. An a priori flux identifiability analysis is required in order to determine whether a 13C‐labeling experiment allows the identification of all the fluxes. In this article, we propose a method for identifiability analysis that is based on the recently introduced ‘cumomer’ concept. The method improves upon previous identifiability methods in that it provides a way of systematically reducing the metabolic network on the basis of structural elements that constitute a network and to use the implicit function theorem to analytically determine whether the fluxes in the reduced network are theoretically identifiable for various types of real measurement data. Application of the method to a realistic flux identification problem shows both the potential of the method in yielding new, interesting conclusions regarding the identifiability and its practical limitations that are caused by the fact that symbolic calculations grow fast with the dimension of the studied system. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 505–516, 2001.
Analysis of glycosaminoglycan‐derived disaccharides in biologic samples by capillary electrophoresis and protocol for sequencing glycosaminoglycans
Authors: Lamari F. N. , Militsopoulou M. , Mitropoulou T. N. , Hjerpe A. , Karamanos N. K. 
Published: September 2002

AbstractGlycosaminoglycans are biologically significant carbohydrates which either as free chains (hyaluronan) or constituents of proteoglycans (chondroitin/dermatan sulfates, heparin, heparan sulfate and keratan sulfate) participate and regulate several cellular events and (patho)physiological processes. Capillary electrophoresis, due to its high resolving power and sensitivity, has been successfully used for the analysis of glycosaminoglycans. Determination of compositional characteristics, such as disaccharide sulfation pattern, is a useful prerequisite for elucidating the interactions of glycosaminoglycans with matrix effective molecules and, therefore, essential in understanding the biological functions of proteoglycans. The interest in the field of characterization of such biologically important carbohydrates is soaring and advances in this field will signal a new revolution in the area of glycomics equivalent to that of genomics and proteomics. This review focuses on the capillary electrophoresis methods used to determine the disaccharide pattern of glycosaminoglycans in various biologic samples as well as advances in the sequence analysis of glycosaminoglycans using both chromatographic and electrophoretic techniques. Copyright © 2002 John Wiley & Sons, Ltd.
A study of chiral recognition for NBD‐derivatives on a Pirkle‐type chiral stationary phase
Authors: Kato Masaru , Fukushima Takeshi , Shimba Nobuhisa , Shimada Ichio , Kawakami Yoshiyuki , Imai Kazuhiro 
Published: September 2002

AbstractA chiral stationary phase (CSP 1) derived from an (S)‐N‐3,5‐dinitrobenzoyl‐1‐naphthylglycine showed excellent enantiomeric separation for amino acid derivatives with a fluorogenic reagent, 4‐fluoro‐7‐nitro‐2,1,3‐benzoxadiazole (NBD‐F), in high‐performance liquid chromatography (HPLC). We compared elution profiles (separation factor and elution order) of NBD‐amino acids and their analogs on HPLC, to determine the diastereomeric complex between the chiral moiety of CSP 1 and NBD‐amino acid, which is responsible for the chiral recognition. 1H‐NMR studies of a mixture of model compound of CSP 1 and NBD‐Ala suggest that the diastereomeric complex is composed of two hydrogen bonding sites at the amino proton and oxygen atom, and a π–π interaction by the benzofurazan structure (2,1,3‐benzoxadiazole) of NBD‐amino acid. Furthermore CSP 1 was able to separate esters, amides and α‐methyl amino acids derivatized with NBD‐F. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

ABD‐F

4‐aminosulfonyl‐7‐fluoro‐2,1,3‐benzoxadiazole

APCI

atmospheric chemical ionization

CSP

chiral stationary phase;

DCC

N,N′‐dicyclohexylcarbodiimide;

DMAP

4‐dimethylamino pyridine

DBD‐F

4‐(N,N′‐dimethylaminosulfonyl‐7‐fluoro‐2,1,3‐benzoxadiazole

DNM

[3,5‐dinitrophenylamido‐(s)‐1‐naphthylglycine]

HBD‐F

4‐fluoro‐2,1,3‐benzoxadiazole

NBD‐CL

4‐chloro‐7‐nitro‐2,1,3‐benzoxadiazole

NBD‐F

4‐fluoro‐7‐nitro‐2,1,3‐benzoxadiazole

TFA

trifluoroacetic acid
Determining the procedure for routine residue monitoring of sulfamethazine in edible animal tissues
Authors: Furusawa Naoto 
Published: September 2002

AbstractA simplified method to determine/identify residual sulfamethazine (SMZ) in edible tissues from cattle, pigs, chickens and sheep by a high‐performance liquid chromatography (HPLC) with a photo‐diode array detector is presented. The sample preparation was performed by homogenizing with 30% (v/v) ethanol in water followed by an Ultrafree®‐MC/PL as a centrifugal ultra‐filtration unit. For determination/identification of SMZ, a reversed‐phase C4 column and a mobile phase of 15% (v/v) ethanol in water with a photo‐diode array detector was used. Average recoveries from spiked SMZ (0.1–1.0 mg kg−1) were ≥80% with coefficients of variation between 1.3 and 4.3%. The limits of quantitation were calculated to be 0.057–0.060 mg kg−1. The total time and solvent required for the analysis of one sample were <40 min and <2 mL of ethanol, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Determination of trimebutine maleate in rat plasma and tissues by using capillary zone electrophoresis
Authors: Li Famei , Yu Lining 
Published: September 2002

AbstractA simple and rapid capillary zone electrophoresis method was developed for the determination of trimebutine maleate in rat plasma and tissues. Rat plasma and tissue homogenates were mixed with acetonitrile containing internal standard, ephedrine hydrochloride, and then centrifuged. The supernatant was dried under a stream of nitrogen, and the residue was reconstituted in methanol–water (1:1). The electrophoresis was performed in uncoated capillary with 30 mmol/L phosphate buffer of pH 6.0 as the separation electrolyte. The applied voltage was 10 kV and the UV detection was set at 214 nm. The peak height ratio vs concentration in plasma or homogenates was linear over the range of 5–500 ng/mL and the limit of quantitation was 5 ng/mL. The intra‐ and inter‐day precision was RSD < 14% and <15%. The accuracy was relative error (RE) within ± 14%. This method was applied to studying the pharmacokinetics and tissue distribution after a single dose of trimebutine maleate was administrated to the rats. The Tmax, AUC, Cmax and t1/2 were 30 min, 7.8 × 102 (ng/mL) min, 39 ng/mL and 1.7 × 102 min. The drug distribution was found in a decreasing order of liver, kidney, spleen, lung and heart. Copyright © 2001 John Wiley & Sons, Ltd.
A rapid, sensitive high performance liquid chromatographic method for the determination of meropenem in pharmaceutical dosage form, human serum and urine
Authors: Özkan Yalcin , Küçükgüzel İlkay , Özkan Sibel A. , Aboul‐Enein Hassan Y. 
Published: September 2002

AbstractA new, simple, precise and rapid high performance liquid chromatographic method was developed for the determination of meropenem in human serum, urine and pharmaceutical dosage forms. Chromatography was carried out on an LC18 column using a mixture of 15 mM KH2PO4:acetonitrile:methanol (84:12:4; v/v/v), adjusted to pH 2.8 with H3PO4. The proposed method was conducted using a reversed‐phase technique, UV monitoring at 307.6 nm and cefepime as an internal standard. The retention times were 5.98 and 7.47 min for cefepime and meropenem, respectively. The detector response was linear over the concentration range of 50–10,000 ng/mL. The detection limit of the procedure was found to be 22 ng/mL. The detection limit for meropenem in human plasma was 108.4 ng/mL and the corresponding value in human urine was 179.3 ng/mL. No interference from endogenous substances in human serum, urine and pharmaceutical preparation was observed. The proposed method is sufficiently sensitive for determination of the concentrations of meropenem and may have clinical application for its monitoring in patients receiving the drug. Copyright © 2001 John Wiley & Sons, Ltd.
Quantification of D/L‐aspartic acids in Aplysia californica central nervous system by β‐cyclodextrin modified micellar electrokinetic chromatography
Authors: Zhao Shulin , Liu Yi‐Ming 
Published: September 2002

AbstractIn presence of an organic modifier (e.g. methanol), separation of amino acid enantiomers tagged with naphthalene‐2,3‐dicarboxaldehyde by β‐cyclodextrin modified micellar electrokinetic chromatography was dramatically improved. Coupled with laser‐induced fluorescence detection, the method was well suited for analysis of D/L‐amino acid enantiomers present in mass/volume‐limited biological samples such as cell clusters. The five major ganglia dissected from the central nervous system of Aplysia californica, a widely used neuronal model, were analyzed to determine D‐ and L‐aspartic acid enantiomers both free and bound in proteins/tissue matrix. The analyses revealed high levels of free D‐aspartic acid ranging from 0.13 to 0.82 µmol/g wet tissue (or 6.0–21.2% of the total free aspartic acid) in all of the five ganglia. However, no D‐aspartic acid was detected bound in protein/tissue matrix. The content of free D‐aspartic acid in the liver tissue was also found below the detection limit of the method, which was 1 × 10−8 M. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

CBI

1‐cyano‐2‐substituted benz[f]isoindole

CSF

cerebrospinal fluid

D‐Asp

D‐aspartic acid D‐Ser, D‐Serine

FITC

fluorescein isothiocyanate

KCN

potassium cyanide

OPA

ophthaldialdehyde

NDA

naphthalene‐2,3‐di‐carboxaldehyde

SDS

sodium dodecyl sulfate

TEA

triethylamine.
Simultaneous determination of clozapine, norclozapine and clozapine‐N‐oxide in human plasma by high‐performance liquid chromatography with ultraviolet detection
Authors: Liu Y. Y. , van Troostwijk L. J. A. E. Doude , Guchelaar H.‐J. 
Published: September 2002

AbstractA reversed‐phase high‐performance liquid chromatographic (HPLC) method for the simultaneous determination of clozapine and its two major metabolites, norclozapine and clozapine‐N‐oxide in human plasma has been developed and validated. The isocratic HPLC assay uses a mobile phase consisting of an acetonitril‐buffered aqueous solution containing 146 µL of triethylamine and 200 µL of 85% phosphoric acid, adjusted to pH 3.3 with 10% potassiumhydroxide solution (400:600, v/v) at a flow‐rate of 0.8 ml/min and a Lichrospher 100 RP‐18 reversed‐phase column and UV detection at 215 nm. Doxepine was used as the internal standard. Mean recoveries for clozapine, norclozapine, clozapine‐N‐oxide and doxepine were 95%, 98%, 96% and 94%, respectively, whereas the respective mean repeatability coefficients of variation were 3.4%, 2.7%, 4.3% and 0.9%. Reproducibility coefficients of variation were 1.3%, 1.8%, 3.6% and 0.5%, respectively. The mean correlation coefficient for the linear calibration curve (n = 2) for clozapine and norclozapine at a concentration range of 100–1600 ng/mL was 0.9998 and 0.9997, respectively; for clozapine‐N‐oxide (20–200 ng/mL) it was found to be 0.9986. The lower limits of quantitation were 12.5 ng/mL, 10 ng/mL and 12.5 ng/mL for clozapine, norclozapine and clozapine‐N‐oxide, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

LLQ

lower limit of quantitation.
Moral justification forTarasoff‐type warnings and breach of confidentiality: a clinician's perspective
Authors: Gutheil Thomas G. 
Published: September 2002

AbstractAfter brief review of the background and context of theTarasoffcase and its impact on clinicians, the author examines the “Tarasoffwarning,” proposed in the 1974Tarasoffopinion, from a moral position, with brief discussion of its clinical and risk management dimensions. Moral issues considered include confidentiality itself, agency, fiduciary duty, a shift in the victim paradigm, the emergency context, a novel risk, and a proposed approach. The dilemma presented by the originalTarasofffact situation is re‐examined. The author stresses the need for individualized responses to the risks posed by patients. Copyright © 2001 John Wiley & Sons, Ltd.
WWW courseware in applied science: Cases and lessons
Authors: Froese Thomas , Zhu David , Bhat Shankar 
Published: September 2002

AbstractA project was conducted to investigate WWW courseware for a variety of applications to support a university engineering degree program. The overall results in terms of learning effectiveness, teaching efficiency, and distance education are discussed, as are lessons learned relating to development considerations and methodologies. An approach of assessing and comparing the various learning elements of both traditional and on‐line course delivery is presented. Three cases of development modules are then described, spanning general course support, on‐line instruction, and laboratory support. © 2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 63–77, 2001
Designing the microprocessor with Abel‐HDL
Authors: Guŝtin Veselko 
Published: September 2002

AbstractIn this article we introduce the use of the programmable logic circuit in students' work as an example of configuring the CPU (central processing unit). Since the concept of an in‐system configurable logic circuit is becoming increasingly popular, we now use it for the purpose of logic design. We suggest to students that they use programmable logic, as in constructing the CPU, with their own designed functions that are directly implemented in logic. Such an approach could greatly increase the understanding of the architectural concept of the CPU. © 2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 87–92, 2001
Magnetostatic analysis of a brushless DC motor using a two‐dimensional partial differential equation solver
Authors: Kostaridis A. , Soras C. , Makios V. 
Published: September 2002

AbstractA finite element, magnetostatic analysis, of a brushless direct current motor containing non‐linear materials and permanent magnets is presented. The analysis is performed with PDEase™, a low cost, two‐dimensional partial differential equation solver. The descriptor file is remarkably short and easy to understand, enabling students to focus on the application and not on the finite element method. © 2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 93–100, 2001
Assessing volunteer motives: a comparison of an open‐ended probe and Likert rating scales
Authors: Allison Lora D. , Okun Morris A. , Dutridge Kathy S. 
Published: September 2002

AbstractThe purpose of the present study was to compare the motives of volunteers (career, esteem, protective, social, understanding, and value) as assessed by an open‐ended probe and the Volunteer Functions Inventory (VFI) which employs a Likert rating scale. One‐hundred‐and‐twenty‐nine individuals, who volunteered for an organization that focuses on episodic volunteering in the community, completed both measures of volunteer motives and reported their frequency of volunteering for the organization. The Spearman rank correlation between the rankings of the six volunteer motives in the two distributions was 0.71. The maximum variance shared between the same motive as assessed by the two methods was 0.14. Frequency of volunteering for the organization was predicted by the value (positive predictor) and social (negative predictor) VFI scale scores. A post hoc analysis of the data from the open‐ended probe revealed three additional motives for volunteering—enjoyment, religiosity, and team building. Copyright © 2002 John Wiley & Sons, Ltd.
Evidence for the involvement of polyunsaturated fatty acids in the regulation of long‐chain acyl CoA thioesterases and peroxisome proliferation in rat carcinosarcoma
Authors: Ramos Karina L. , Colquhoun Alison 
Published: September 2002

AbstractThe feeding of high‐fat diets rich in polyunsaturated fatty acids (PUFAs) caused a marked increase in the acyl CoA thioesterase activity of the Walker 256 tumour. Diets containing lower levels of PUFAs did not alter the activity of acyl CoA thioesterase and the exposure of LLC‐WRC256 tumour cells, in culture, to PUFAs (150 μM) also was ineffective in altering activity. The tumours from n‐3 PUFA‐rich and control diets were analysed by transmission electron microscopy in order to compare peroxisomal content. The presence of PUFAs led to an almost 10‐fold increase in the number of peroxisomes present in the tumour tissue. A common feature of the PUFA‐treated tumour was the presence of many cells containing highly condensed heterochromatin at the periphery of the nucleus, indicative of apoptosis. The sparsity of endoplasmic reticulum and the lack of detection of mitochondrial acyl CoA thioesterase, MTE‐I, led to the conclusion that the increase in tumour acyl CoA thioesterase activity may be due to an increase in the activity of the peroxisomal enzyme. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of polyamines on DNA synthesis using various subcellular DNA polymerases extracted from normal rat liver, tumour‐bearing rat liver, and tumour cells
Authors: Taguchi Takahiko , Kurata Sumiko , Ohashi Mochihiko 
Published: September 2002

AbstractThe effects of polyamines on DNA synthesis in vitro using various subcellular DNA polymerase fractions from normal and tumour‐bearing rat livers, and tumour cells were investigated. When nuclear and mitochondrial DNA polymerase fractions were used, DNA synthesis on activated DNA was increased 3.5–8‐fold by the addition of 20 mM putrescine or cadaverine. However, DNA synthesis was not stimulated by the addition of spermidine or spermine at any concentration tested. In contrast, DNA synthesis using the cytoplasmic DNA polymerase fraction was not stimulated at various concentrations of any of the four polyamines tested. The stimulatory effects of putrescine and cadaverine were absent when nuclear fractions from tumour‐bearing rat liver or from tumour cells were used. In addition, in vitro DNA synthesis was not stimulated by 20 mM putrescine or cadaverine when nuclear extracts from the livers of rats administered putrescine subcutaneously were used. The specific activities of DNA polymerases extracted from tumour cells and tumour‐bearing rat liver were already fully stimulated. These results suggest that DNA polymerases in tumour cells and tumour‐bearing liver cells are stimulated by trapped putrescine produced in tumour cells and are thus no longer activated by exogenous putrescine. Copyright © 2001 John Wiley & Sons, Ltd.