bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epithelial cell dynamics in rabbit cecum and proximal colon P1
Authors: Grant T. Dawn , Specian Robert D. 
Published: August 2002

AbstractThe large intestine of mammals has long been viewed as an osmoregulatory organ, and evidence suggests that fluid and solute transport mechanisms within the intestine are heterogenous, varying depending on the particular segment involved. Variations in function are often matched by morphological correlates, but despite the widespread use of rabbit large intestine as an experimental model, there is a lack of knowledge about the cellular makeup and dynamics in the colonic mucosal epithelium. The presence of mitotic figures and immunohistochemical localization of proliferating cell nuclear antigen (PCNA) were used to identify the proliferative zone(s). Cellular migration patterns were determined through the use of the thymidine analog 5‐bromo‐2‐deoxyuridine (BrdU) over a 24‐, 48‐, and 72‐hr period. Apoptotic nuclei were identified utilizing terminal deoxynucleotidyl transferase d‐UTP nick‐end labeling (TUNEL). Both cecum and the initial portion of the proximal colon (P1) exhibited a proliferative zone at or near the crypt base, and migration proceeded upwards toward the surface epithelium lining the intestinal lumen, where apoptosis occurred Turnover time of crypt columnar cells was determined to be about 3 days; that of mucous cells was estimated to be about 5 weeks. Rabbit cecum and proximal colon P1 are similar in their cellular morphology and epithelial cell kinetics. In both, the major proliferative zone is located at or near the crypt base, from which crypt columnar cells migrate toward the lumenal surface epithelium over a period of 3 days. Goblet cell turnover rate is much slower than that of columnar cells. Anat Rec 264:427–437, 2001. © 2001 Wiley‐Liss, Inc.
Vitamin requirements of the cultured flesh fly cells, Sarcophaga peregrina (Diptera, Sarcophagidae)
Authors: Mitsuhashi Jun 
Published: August 2002

AbstractEssential vitamins for the growth of a cell line derived from the flesh fly, Sarcophaga peregrina, were determined. By examining the survivability of continuous passages of the cells in the chemically defined medium lacking one vitamin, thiamine, riboflavin, pantothenate and either niacin or niacinamide were found to be essential for the continuous growth of the flesh fly cells in vitro. Arch. Insect Biochem. Physiol. 37:283–286, 1998. © 1998 Wiley‐Liss, Inc.
Endocrine mechanisms controlling body‐color polymorphism in locusts
Authors: Tanaka Seiji 
Published: August 2002

AbstractThe present article reviews recent published and unpublished findings on the hormonal mechanisms for the control of body‐color polymorphism in locusts. Emphasis is placed on the dark color–inducing factors and their role in the induction of various types of body coloration observed under different environmental conditions. Implantation of corpora cardiaca (CC) taken from normal nymphs of Locusta migratoria induced dark color in nymphs of an albino strain. Using the albino strain for the bioassay, a neuropeptide, [His7]‐corazonin, was identified as a dark color–inducing factor for L. migratoria and Schistocerca gregaria. In the former, depending upon the dose and timing of the injection, this peptide and juvenile hormone developed various body colors looking like those found in nature. The body coloration characteristic of gregarious forms was also induced in isolated albino nymphs and field‐collected solitary nymphs. In S. gregaria, on the other hand, the peptide induced black patterns, but the orange or yellow background color observed in gregarious forms was not induced when the peptide was injected into solitary individuals. [His7]‐corazonin also induced darkening in other grasshoppers and locusts, but not in katydids. Albino L. migratoria developed dark color when implanted with brains or CC taken from other insects belonging to 10 major insect orders, but not with those from Coleoptera. [His7]‐corazonin or a similar compound is widespread among insects and plays a pivotal role in controlling body color in some species and presumably other physiological roles in other species. Arch. Insect Biochem. Physiol. 47:139–149, 2001. © 2001 Wiley‐Liss, Inc.
DNA‐binding properties of the ecdysteroid receptor‐complex (EcR/USP) of the epithelial cell line from Chironomus tentans
Authors: Elke Carsten , Rauch Peter , Spindler‐Barth Margarethe , Spindler Klaus‐Dieter 
Published: August 2002

AbstractDNA‐binding features of EcR and USP were investigated using a 0.4 M NaCl extract of the epithelial cell line of Chironomus tentans by means of electrophoretic mobility shift assays (EMSAs). It is shown that the DNA‐binding is enhanced by hormone administration and that in the hormone dependent shift, both EcR and USP, are present. Furthermore, we demonstrate that under these conditions, EcR/USP form a unique complex on inverted repeat elements (PAL1 and hsp27‐EcRE), while on direct repeat elements (DR1‐5), a second complex with higher mobility is formed. In this second complex, neither EcR nor USP are present. Thus, an additional difference between PAL1 and DR‐elements is the competition of other factors for DR‐elements, modulating its function as an EcRE. A competition EMSA, using PAL1 as radiolabeled probe, reveals the following order of binding strength: PAL1>DR4/5>DR1>DR2/3/hsp27. Surprisingly, using DR1 as radiolabeled probe, shows a different order of binding strength: DR1>DR2>DR3/4/5/PAL1>hsp27. This indicates that the complexes formed on PAL1 are not identical to the ones formed on DR1 and that both are not easily convertible. Furthermore, the affinity of the EcR/USP complex may be altered under various conditions or by interaction with cofactors.Upon hormone administration, DNA binding of the receptor complex is enhanced, but the difference to hormone‐free binding reactions decreases in course of time, indicating an additional hormone independent activation. Arch. Insect Biochem. Physiol. 41:124–133, 1999. © 1999 Wiley‐Liss, Inc.
Gene transfer of a fibronectin peptide inhibits leukocyte recruitment and suppresses inflammation in mouse collagen‐induced arthritis
Authors: Imagawa Tomoyuki , Watanabe Shohei , Katakura Shigeki , Boivin Gregory P. , Hirsch Raphael 
Published: August 2002

AbstractObjectiveCell adhesion plays an essential role in arthritis by recruiting and retaining leukocytes in the joint. Fibronectin, a major extracellular matrix component in synovium, plays a central role in cell–cell and cell–matrix interactions through ligation of cell surface integrins. The present study was designed to determine the effects of gene transfer of a 15–amino acid peptide derived from the 33‐kd carboxy‐terminal cell and heparin‐binding domain of fibronectin (FN‐C/H‐II) on established arthritis in mice.MethodsPlasmid DNA encoding a FN‐C/H‐II minigene under control of the cytomegalovirus promoter was injected intravenously into mice with established collagen‐induced arthritis, and the effects on leukocyte adhesion and recruitment to the joints was determined.ResultsFollowing injection, circulating FN‐C/H‐II could be detected for at least 5 days. Treated mice demonstrated a marked reduction in progression of arthritis. Not only was disease progression halted, but a significant improvement in joint swelling was observed within 2 days of treatment. Leukocyte adhesion and recruitment were inhibited by FN‐C/H‐II, both in vitro and in vivo. Histologic evaluation revealed a marked reduction in infiltration of both neutrophils and lymphocytes into synovium, persisting for at least 10 days.ConclusionThese results suggest that antagonism of cell adhesion by soluble fibronectin peptides may provide an approach to attenuating chronic arthritis.
A longitudinal study of World Wide Web users' information‐searching behavior
Authors: Cothey Vivian 
Published: August 2002

AbstractA study of the “real world” Web information searching behavior of 206 college students over a 10‐month period showed that, contrary to expectations, the users adopted a more passive or browsing approach to Web information searching and became more eclectic in their selection of Web hosts as they gained experience. The study used a longitudinal transaction log analysis of the URLs accessed during 5,431 user days of Web information searching to detect changes in information searching behavior associated with increased experience of using the Web. The findings have implications for the design of future Web information retrieval tools.
Socio‐economic factors in the application of information and communication technologies in Nigerian print media
Authors: Ehikhamenor Fabian A. 
Published: August 2002

AbstractInformation and communication technologies (ICTs) have opened up new opportunities for the Nigerian print media to improve on their products and services. This study explores the socio‐economic factors associated with the adoption and use of ICTs by the media. Of a total of 54 socio‐economic factors considered, exactly 50% were found to have significant influence on the adoption and success of ICT applications. The factors that have the greatest positive influence on adoption of ICTs include organizational goal, profitability, organizational image, communication in the organization, productivity, and openness of workers to change. They also constitute success factors in the use of these technologies. The factors that constrained adoption and also successful application include high rate of inflation, unfavourable exchange rate of the naira to the dollar, low wage level, huge costs, low gross national product, inadequate funding, and unstable political situation. These constraining factors are indicators of economic weakness and political uncertainty. It seems that the significance of such factors, which are completely external to a business organization, was often underestimated in studies of organizational performance in developing countries.
Prescreening of choice options in ‘positive’ and ‘negative’ decision‐making tasks
Authors: Levin Irwin P. , Prosansky Caryn M. , Heller Daniel , Brunick Brad M. 
Published: August 2002

AbstractResearch on prescreening processes in decision making was extended by manipulating task valence in a series of three experiments. In Experiments 1 and 2, half the subjects had the ‘positive’ task of screening and then selecting someone to hire for a job and half had the ‘negative’ task of screening and then selecting someone to fire, where the choice options (worker descriptions) were the same in each task. In Experiment 1 some subjects were instructed to list options they would include for further consideration and some were instructed to list options they would exclude from further consideration. More options were screened out in the inclusion condition than in the exclusion condition and in the firing task than in the hiring task. Subjects in Experiment 2 were allowed to decide for themselves whether to use inclusion or exclusion in screening options. The main results from Experiment 1 were replicated. Also, subjects in the hiring task were more likely than subjects in the firing task to select inclusion as a strategy for prescreening options. In Experiment 3 the positive task involved adding stocks to a portfolio following an unexpected financial gain and the negative task involved disposing of stocks following a financial setback. Again, more options were screened out by subjects selecting the inclusion strategy than by exclusion subjects, but differences between the positive and negative tasks were not found. Results were explained in terms of a ‘status quo’ bias for adding or deleting options that transcends task differences and a positivity bias in judging people that distinguishes judgments in different task domains. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of dose dependences for bioeffects of continuous‐wave and high‐peak power microwave emissions using gel‐suspended cell cultures†
Authors: Pakhomov Andrei G. , Gajšek Peter , Allen Lori , Stuck Bruce E. , Murphy Michael R. 
Published: August 2002

AbstractThe study compared bioeffects of continuous wave (CW) microwaves and short, extremely high power pulses (EHPP) at the same carrier frequency (9.3 GHz) and average power (1.25 W). The peak transmitted power for EHPP was 250 kW (0.5‐μs pulse width, 10 p.p.s.), producing the E field of 1.57 MV/m in the waveguide. A biological endpoint was the density of yeast cells, achieved after a 6 h growth period in a solid nutrient medium (agarose gel) during EHPP or CW exposure. Owing to power losses in the medium, the specific absorption rate (SAR) ranged from 3.2 kW/kg at the exposed surface of the sample to 0.6 mW/kg at 24 mm depth. Absorption and penetration of EHPP was identical to CW, producing peak SAR values 200 000 times higher than the average SAR, as high as 650 MW/kg at the surface. CW and EHPP exposures produced highly nonuniform but identical heating patterns in exposed samples. Following the exposure, the samples were sliced in a plane perpendicular to the wave propagation, in order to separate cell masses exposed at different SAR levels. Cell density in the slices was determined by nephelometry and compared to unexposed parallel control samples. Cell density was strongly affected by irradiation, and the changes correlated well with the local temperature rise. However, the data revealed no statistically significant difference between CW and EHPP samples across the entire studied range of SAR levels (over six orders of magnitude). A trend (P < 0.1) for such a difference was observed in slices that were exposed at a time average SAR of 100 W/kg and higher, which corresponded to peak SAR above 20 MW/kg for the EHPP condition. These numbers could be indicative of a threshold for a specific (not merely thermal) exposure effect if the trend is confirmed by future studies. Bioelectromagnetics 23:158–167, 2002. Published 2002 Wiley‐Liss, Inc.
Cell proliferation and growth in C. elegans
Authors: Lambie Eric J. 
Published: August 2002

AbstractThe cell division and differentiation events that occur during the development of the nematode Caenorhabditis elegans are nearly identical between different individuals, a feature that distinguishes this organism from larger and more complex metazoans, such as humans and Drosophila. In view of this discrepancy, it might be expected that the regulation of cell growth, division and differentiation in C. elegans would involve mechanisms separate from those utilized in larger animals. However, the results of recent genetic, molecular and cellular studies indicate that C. elegans employs an arsenal of developmental regulatory mechanisms quite similar to those wielded by its arthropod and vertebrate relatives. Thus, the nematode system is providing both novel and complementary insights into the general problem of how growth and patterning events are integrated in development. This review offers a general perspective on the regulation of cell division and growth in C. elegans, emphasizing recent studies of these crucial aspects of development. BioEssays 24:38–53, 2002. © 2002 John Wiley & Sons, Inc.
Midline and laterality defects: Left and right meet in the middle†
Authors: Roessler Erich , Muenke Maximilian 
Published: August 2002

AbstractThe aim of this review is to summarize some of the recent advances in molecular embryology that help to explain the pathogenesis of holoprosencephaly (HPE), or its related malformation in model organisms, cyclopia, and laterality defects in humans, derived from detailed analysis of similar malformations in animal models. Recently, defects in several developmental pathways including those operated by the Sonic hedgehog and Nodal signaling factors have been implicated as causes of HPE or laterality defects in humans. Here we summarize the findings in animal models that indicate that both defects can be explained by mechanisms that relate to the proper development of the axial midline in vertebrates. BioEssays 23:888–900, 2001. Published 2001 John Wiley & Sons, Inc.
Active site structure and dynamics of cytochrome c3 from Desulfovibrio gigas immobilized on electrodes
Authors: Jalila A. , Daniel Simaan , Murgida H. , Hildebrandt Peter 
Published: August 2002

AbstractCytochrome c3 from Desulfovibrio gigas is electrostatically adsorbed on Ag electrodes coated with self‐assembled monolayers (SAMs) of 11‐mercaptoundecanoic acid. The redox equilibria and electron transfer dynamics of the adsorbed four‐heme protein are studied by surface enhanced resonance Raman spectroscopy. Immobilization on the coated electrodes does not cause any structural changes in the redox sites. The potential‐dependent stationary experiments distinguish the redox potential of heme IV (−0.19 V versus normal hydrogen electrode) from those of the other hemes for which an average value of −0.3 V is determined. Taking into account the interfacial potential drops, these values are in good agreement with the redox potentials of the protein in solution. The heterogenous electron transfer between the electrode and heme IV of the adsorbed cytochrome c3 is analyzed on the basis of time‐resolved experiments, leading to a formal electron transfer rate constant of 15 s−1, which is a factor of 3 smaller than that of the monoheme protein cytochrome c. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 331– 334, 2002
Spectral decomposition of intracellular complex fluorescence using multiple‐wavelength phase modulation lifetime determination: Technical approach and preliminary applications
Authors: Praus Petr , Gaskova Dana , Kocisova Eva , Chaloupka Roman , Stepanek Josef , Bok Jiri , Rejman Dominik , Rosenberg Ivan , Turpin Pierre‐Yves , Sureau Franck 
Published: August 2002

AbstractLifetime‐based spectral decomposition using a frequency‐domain phase/modulation technique is developed on a microspectrofluorimeter prototype. In a fluorescent mixture with strongly overlapping components, such measurements enable us to not only obtain excited state lifetimes of each fluorescent component but also determine the specific spectral contribution of each species without the use of any model spectra. Examples of such applications are first given for complex mixtures of highly overlapping fluorescent components in solution. Preliminary results concerning cellular applications are also reported. This allows us to follow the cellular uptake and intracellular stability of fluorescent labeled modified oligonucleotides in the context of antisense strategy studies. Indeed, the intracellular signal from the fluorescent label bound to oligonucleotides can be distinguished from those of the free label by its specific excited state lifetime. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 339–343, 2002
A study of conformational stability of poly(L‐alanine), poly(L‐valine), and poly(L‐alanine)/poly(L‐valine) blends in the solid state by 13C cross‐polarization/magic angle spinning NMR
Authors: Murata Katsuyoshi , Kuroki Shigeki , Kimura Hideaki , Ando Isao 
Published: August 2002

Abstract13C cross‐polarization/magic angle spinning (CP/MAS) NMR and 1H T1ρ experiments of poly(L‐alanine) (PLA), poly(L‐valine) (PLV), and PLA/PLV blends have been carried out in order to elucidate the conformational stability of the polypeptides in the solid state. These were prepared by adding a trifluoroacetic acid (TFA) solution of the polymer with a 2.0 wt/wt % of sulfuric acid (H2SO4) to alkaline water. From these experimental results, it is clarified that the conformations of PLA and PLV in their blends are strongly influenced by intermolecular hydrogen‐bonding interactions that cause their miscibility at the molecular level. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 26–33, 2002
Use of conserved key amino acid positions to morph protein folds
Authors: Reddy Boojala V. B. , Li Wilfred W. , Bourne Philip E. 
Published: August 2002

AbstractBy using three‐dimensional (3D) structure alignments and a previously published method to determine Conserved Key Amino Acid Positions (CKAAPs) we propose a theoretical method to design mutations that can be used to morph the protein folds. The original Paracelsus challenge, met by several groups, called for the engineering of a stable but different structure by modifying less than 50% of the amino acid residues. We have used the sequences from the Protein Data Bank (PDB) identifiers 1ROP, and 2CRO, which were previously used in the Paracelsus challenge by those groups, and suggest mutation to CKAAPs to morph the protein fold. The total number of mutations suggested is less than 40% of the starting sequence theoretically improving the challenge results. From secondary structure prediction experiments of the proposed mutant sequence structures, we observe that each of the suggested mutant protein sequences likely folds to a different, non‐native potentially stable target structure. These results are an early indicator that analyses using structure alignments leading to CKAAPs of a given structure are of value in protein engineering experiments. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 139–145, 2002
Steam pressure disruption of municipal solid waste enhances anaerobic digestion kinetics and biogas yield
Authors: Liu H. W. , Walter H. K. , Vogt G. M. , Vogt H. S. , Holbein B. E. 
Published: August 2002

AbstractBiomass waste, including municipal solid waste (MSW), contains lignocellulosic‐containing fiber components that are not readily available as substrates for anaerobic digestion due to the physical shielding of cellulose imparted by the nondigestible lignin. Consequently, a substantial portion of the potentially available carbon is not converted to methane and the incompletely digested residues from anaerobic digestion generally require additional processing prior to their return to the environment. We investigated and developed steam pressure disruption as a treatment step to render lignocellulosic‐rich biomass more digestible and as a means for increasing methane energy recovery. The rapid depressurization after steam heating (240°C, 5 min.) of the nondigested residues following a 30‐day primary digestion of MSW caused a visible disruption of fibers and release of soluble organic components. The disrupted material, after reinoculation, provided a rapid burst in methane production at rates double those observed in the initial digestion. This secondary digestion proceeded without a lag phase in gas production, provided ∼40% additional methane yields, and was accompanied by a ∼40% increase in volatile solids reduction. The secondary digestate was found to be enriched in lignin and significantly depleted in cellulose and hemi‐cellulose components when compared to primary digestate. Thus, steam pressure disruption treatment rendered lignocellulosic substrates readily accessible to anaerobic digestion bacteria and improved both the kinetics of biogas production and the overall methane yield from MSW. Steam pressure disruption is central to a new anaerobic digestion process approach including sequential digestion stages and integrated energy recovery, to improve process yields, provide cogenerated energy for process needs, and to provide effective reuse and recycling of waste biomass materials. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 121–130, 2002.