bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of weathering on in situ portable X‐ray fluorescence analyses of geological outcrops: dolerite and rhyolite outcrops from the Preseli Mountains, South Wales
Authors: Potts P. J. , Bernardini F. , Jones M. C. , Williams‐Thorpe O. , Webb P. C. 
Published: December 2005

AbstractLaboratory experiments were undertaken to investigate the effect of weathering on dolerite and rhyolite samples from the Preseli Mountains, South Wales, an area of archaeological significance for the provenancing of archaeological artefacts. Portable XRF (PXRF) analysis was used to construct a depth profile of elemental concentrations through the weathering layer of suitable rock samples. These measurements were made by sequentially grinding away successive layers, each time measuring the newly exposed surface by PXRF. The elements studied included K, Ca, Ti, Mn, Fe, Ba, Nb, Pb, Sr, Y and Zr. In dolerite samples, Ca, Fe and Y were generally depleted in heavily weathered surface layers, whereas K and Pb were enhanced, the latter element significantly so, probably as a result of anthropogenic activities (emissions from leaded automobile fuel). Element behaviour in rhyolites was less consistent. A correction factor was derived for each element based on the ratio of the weathered surface concentration to the corresponding steady‐state (fresh rock) concentration beneath the altered layer. This correction factor was evaluated as a possible means of compensating for elemental discrepancies when measuring weathered surfaces. Improved data were obtained for a significant number of elements, but further work is required to evaluate this procedure fully. Copyright © 2005 John Wiley & Sons, Ltd.
Peroperative ketamine and morphine for postoperative pain control after lumbar disk surgery
Authors: Aveline Christophe , Le Hetet Hubert , Vautier Pierre , Gautier Jean François , Bonnet Francis 
Published: December 2005

AbstractBackground Ketamine, a N‐methyl‐d‐aspartate receptor antagonist, may reduce postoperative opioid demand and improve postoperative analgesia.Methods Sixty‐nine patients scheduled for lumbar disk surgery under general anaesthesia were enrolled in a randomised, double‐blind study comparing three analgesic combinations that were started before surgical incision: morphine 0.1 mg kg−1 alone (group M; n = 23); ketamine 0.15 mg kg−1 alone (group K; n = 22); and a combination of morphine 0.1 mg kg−1 with ketamine 0.15 mg kg−1 (group KM; n = 23). Postoperatively patient‐controlled analgesia was provided with intravenous morphine. Morphine consumption was assessed during 24 H, and pain scores were measured using a visual analogue scale (VAS) at rest and on mobilisation, during the first two postoperative days.Results In group KM, less i.v. morphine was administered in the post anaesthesia care unit than in group M (median [range]: 0 mg [0–2] vs. 7 mg [6–9], P = 0.009). Cumulative 24 H morphine consumption was reduced by 57% in group KM vs. group M, and by 48% in group KM vs. group K. Postoperative VAS scores were lower in group KM vs. groups K and M. Maximal VAS score on mobilization was reduced in group KM compared to groups K and M (38 mm [35–45] vs. 52 mm [48–59] and vs. 59 mm [55–64], in groups KM, K and M, respectively, P = 0.05 and P = 0.002). The incidence of postoperative nausea and vomiting was decreased in group KM compared to group M (21.7% vs. 43.5%, P = 0.001).Conclusion Ketamine small‐dose, combined with morphine improves postoperative analgesia and reduces opioid‐related side effects in lumbar disk surgery.
Nitric oxide regulates the proliferation of chick embryo retina cells by a cyclic GMP‐independent mechanism
Authors: Magalhães Cristiane R. , Socodato Renato E.S. , Paes‐de‐Carvalho Roberto 
Published: December 2005

AbstractNitric oxide (NO) is an intercellular messenger involved in many physiological and pathological processes of vertebrate and invertebrate animal tissues. In the embryonic chick retina, nitric oxide synthase (NOS) activity and a system for l‐arginine transport between neurons and glial cells were described, supporting the idea that nitric oxide is a critical molecule during retinal development. In the present work we show that nitric oxide is a modulator of cell proliferation in chick embryo retina. Mixed cultures of retinal neurons and glial cells were submitted to [3H]‐thymidine incorporation after drug treatment. Incubation for 24 h with the NO donors S‐nitroso‐N‐acetyl‐penicillamine (SNAP) or Spermine nitric oxide (SpNO) complex promoted a decrease of approximately 70% of [3H]‐thymidine incorporation in a dose‐dependent manner. SNAP did not increase Lactate dehydrogenase release and its effect was not mimicked by 8‐bromo cyclic GMP, or blocked by the guanylate cyclase inhibitor 1H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one (ODQ), indicating that the effect was not due to cell death or mediated by increases of cyclic GMP levels. The inhibition was completely prevented by dithiotreitol (DTT), strongly indicating the participation of an S‐nitrosylation mechanism. SNAP blocked the increase of [3H]‐thymidine incorporation induced by ATP. Using purified cultures of glial cells we showed that the NO donor SNAP produced an inhibition of 50% in cell proliferation and did stimulate ERK1/2 phosphorylation, indicating that the inhibition of this pathway was not involved in its cytostatic effect. [3H]‐Thymidine autoradiography of mixed cultures showed labeling of oval nuclei of glial flat cells. The injection of eggs with SNAP also did promote an intense inhibition of [3H]‐thymidine incorporation in retinas from 9‐day‐old embryos. These data suggest that nitric oxide affects the proliferation of chick embryo retina glial cells in culture or “in vivo” through cyclic GMP and ERK‐independent pathways.
Catalytic Activity of β‐Amylase from Barley in Different Pressure/Temperature Domains
Authors: Heinz Volker , Buckow Roman , Knorr Dietrich 
Published: December 2005

AbstractThe depolymerization of starch by β‐amylase during exposure to hydrostatic pressure up to 700 MPa and within a temperature range from 20 to 70 °C has been investigated. Inactivation of the enzyme as well as alterations in conversion speed in response to combined pressure‐temperature treatments were assessed by analyzing the kinetic rate constants. At 200 MPa a significant stabilization of the enzyme against heat inactivation was observed. However, high pressure also impedes the catalytic reaction and a progressive reduction of the conversion rate constants with increasing pressure was found at all temperatures investigated. For the overall reaction of maltose liberation from soluble starch in ACES buffer at pH 5.6 an optimum was identified at 106 MPa and at 63 °C, which is approximately 7 °C above the local maximum at ambient pressure (0.1 MPa). Gelatinization of nonsoluble starch granules in response to pressure‐temperature (p‐T) treatment has been inspected by phase‐contrast microscopy and yielded circular curves of identical effect in the p‐T plane.
Directional Surface Plasmon‐Coupled Emission from a 3 nm Green Fluorescent Protein Monolayer
Authors: Kostov Yordan , Smith Derek S. , Tolosa Leah , Rao Govind , Gryczynski Ignacy , Gryczynski Zygmunt , Malicka Joanna , Lakowicz Joseph R. 
Published: December 2005

AbstractHigh‐sensitivity detection schemes are of great interest for a number of applications. Unfortunately, such schemes are usually high‐cost. We demonstrate a low‐cost approach to a high‐sensitivity detection scheme based on surface plasmon‐coupled emission (SPCE). The SPCE of a monomolecular layer of green fluorescent protein (GFP) is reported here. The protein was electrostatically attached to a thin, SiO2‐protected silver film deposited on a quartz substrate. The visible, directional emission of GFP was observed at a sharp, well‐defined angle of 47.5° from the normal to the coupling prism, and the spectrum corresponded to that of GFP. The SPCE resulting from the reverse Kretschmann configuration showed a 12‐fold enhancement over the free space fluorescence. The directional emission was 97% p‐polarized. The directionality and high polarization can be coupled with the intrinsic spectral resolution of SPCE to be used in the design miniaturized spectrofluorometers. The observation of SPCE in the visible region of the spectrum from a monolayer of protein opens up new possibilities in protein‐based sensing.
Bioprocess Engineering Issues That Would Be Faced in Producing a DNA Vaccine at up to 100 m3 Fermentation Scale for an Influenza Pandemic
Authors: Hoare Mike , Levy M. Susana , Bracewell Daniel G. , Doig Steven D. , Kong Simyee , Titchener‐Hooker Nigel , Ward John M. , Dunnill Peter 
Published: December 2005

AbstractThe risk of a pandemic with a virulent form of influenza is acknowledged by the World Health Organization (WHO) and other agencies. Current vaccine production facilities would be unable to meet the global requirement for vaccine. As a possible supplement a DNA vaccine may be appropriate, and bioprocess engineering factors bearing on the use of existing biopharmaceutical and antibiotics plants to produce it are described. This approach addresses the uncertainty of timing of a pandemic that precludes purpose‐built facilities. The strengths and weaknesses of alternative downstream processing routes are analyzed, and several gaps in public domain information are addressed. The conclusion is that such processing would be challenging but feasible.
Production of Oligoglucuronans by Enzymatic Depolymerization of Nascent Glucuronan
Authors: Delattre Cédric , Michaud Philippe , Keller Cyril , Courtois Bernard , Courtois Josiane 
Published: December 2005

AbstractAn original bioreactor process for production of oligoglucuronans was developed using the Sinorhizobium meliloti M5N1CS strain that produces glucuronan. This anionic homopolysaccharide was composed of β‐d‐(1,4)‐glucopyranosyluronic residues variably O‐acetylated at C‐3 and/or C‐2 positions according to culture conditions. It was depolymerized during its biosynthesis by addition of a fungal glucuronan lyase activity in broths. After purification by tangential ultrafiltration and low‐pressure liquid chromatography, 1H NMR and ESI‐Q/TOF‐MS characterized the poly‐ and oligoglucuronic acid fractions. This enzymatic bioreactor strategy authorized the production in gram quantity of an unsaturated and no acetylated oligoglucuronan with a degree of polymerization of 3.
Engineering Select Physical Properties of Cross‐Linked Red Blood Cells and a Simple a Priori Estimation of Their Efficacy as an Oxygen Delivery Vehicle within the Context of a Hepatic Hollow Fiber Bioreactor
Authors: Gordon Jason E. , Dare Matthew R. , Palmer Andre F. 
Published: December 2005

AbstractBovine red blood cells (bRBCs) can potentially provide a simplistic and economic means of improving oxygenation within hollow fiber (HF) bioreactor cell cultures. Bovine RBCs are also interesting since many of their physical properties can be altered as a result of glutaraldehyde (G) cross‐linking. Cross‐linking bRBCs produces an oxygen carrier that is expected to be beneficial under specific circumstances (i.e., delivery of oxygen to cells that are sensitive to free hemoglobin (Hb) and cells that require low inlet oxygen tensions). We have examined the osmotic stability and electrophoretic mobility of cross‐linked bRBCs and observed that cross‐linking improves osmotic stability while minimally impacting electrophoretic mobility. The oxygen binding/dissociation properties (P50 and n) of cross‐linked bRBCs were also measured, and under the reported reaction conditions, cross‐linking increased the oxygen affinity and reduced the cooperativity of bRBCs. A basic Krogh tissue cylinder model was then utilized to provide a quick a priori estimate of oxygen delivery and release to hepatocytes housed within a HF bioreactor in order to demonstrate potential oxygenation benefits arising with both normal and cross‐linked bRBC media supplementation. This model showed that bRBCs generally improved oxygen delivery and release to HF cell cultures and that cross‐linked bRBCs are particularly beneficial in specifically targeting oxygen delivery to cells maintained at low inlet oxygen tensions. Additionally, the model showed that bRBC supplementation can significantly improve oxygen delivery without requiring extreme bRBC concentrations.
Hydrogen Production from Glucose by Anaerobes
Authors: Ogino Hiroyasu , Miura Takashi , Ishimi Kosaku , Seki Minoru , Yoshida Hiroyuki 
Published: December 2005

AbstractVarious anaerobes were cultivated in media containing glucose. When 100 mL of thioglycollate medium containing 2.0% (w/v) glucose was used, Clostridium butyricum ATCC 859, NBRC 3315, and NBRC 13949 evolved 227–243 mL of biogas containing about 180 mL of hydrogen in 1 day. Although some strains had some resistance against oxygen, C. butyricum ATCC 859 and 860 did not have it. C.butyricum NBRC 3315 and Enterobacter aerogenes NBRC 13534 produced hydrogen in the presence of glucose or pyruvic acid, and E. aerogenes NBRC 13534 produced hydrogen by not only glucose and pyruvic acid but also dextrin, sucrose, maltose, galactose, fructose, mannose, and mannitol. When a medium containing 0.5% (w/v) yeast extract and 2.0% (w/v) glucose was used, E. aerogenes NBRC 13534 evolved more biogas and hydrogen than C. butyricum NBRC 3315 in the absence of reducing agent.
Rhamnolipid Surfactants: An Update on the General Aspects of These Remarkable Biomolecules
Authors: Nitschke Marcia , Costa Siddhartha G. V. A. O. , Contiero Jonas 
Published: December 2005

AbstractPseudomonas strains are able to biosynthesize rhamnose‐containing surfactants also known as rhamnolipids. These surface‐active compounds are reviewed with respect to chemical structure, properties, biosynthesis, and physiological role, focusing on their production and the use of low‐cost substrates such as wastes from food industries as alternative carbon sources. The use of inexpensive raw materials such as agroindustrial wastes is an attractive strategy to reduce the production costs associated with biosurfactant production and, at same time, contribute to the reduction of environmental impact generated by the discard of residues, and the treatment costs. Carbohydrate‐rich substrates generated low rhamnolipid levels, whereas oils and lipid‐rich wastes have shown excellent potential as alternative carbon sources.
Proteolytically Degradable Hydrogels with a Fluorogenic Substrate for Studies of Cellular Proteolytic Activity and Migration
Authors: Lee Soo‐Hong , Miller Jordan S. , Moon James J. , West Jennifer L. 
Published: December 2005

AbstractWe have developed proteolytically degradable hydrogels with covalently immobilized fluorogenic protease substrates to visualize extracellular proteolytic activity and cell migration in three dimensions. Dye quenched‐bovine serum albumin (DQ‐BSA), a quenched, proteolytically activated fluorogenic substrate, was conjugated to poly(ethylene glycol) (PEG)‐monoacrylate, and the product (DQ‐BSA‐PEG) was then covalently incorporated into proteolytically degradable and cell adhesive PEG hydrogels via photopolymerization. The DQ‐BSA‐PEG substrate in solution and incorporated into hydrogels exhibited significantly enhanced fluorescence after exposure to enzymes. Fibroblasts seeded within this hydrogel spread in three dimensions and extended lamellipodia. Cell migration and proteolytic activity were visualized using confocal microscopy. Proteolytic activity was concentrated near cell surfaces and remained present in the tracks where cell migration had occurred.
Flux Balance Analysis of Photoautotrophic Metabolism
Authors: Shastri Avantika A. , Morgan John A. 
Published: December 2005

AbstractPhotosynthesis is the principal process responsible for fixation of inorganic carbon dioxide into organic molecules with sunlight as the energy source. Potentially, many chemicals could be inexpensively produced by photosynthetic organisms. Mathematical modeling of photoautotrophic metabolism is therefore important to evaluate maximum theoretical product yields and to deeply understand the interactions between biochemical energy, carbon fixation, and assimilation pathways. Flux balance analysis based on linear programming is applied to photoautotrophic metabolism. The stoichiometric network of a model photosynthetic prokaryote,Synechocystissp. PCC 6803, has been reconstructed from genomic data and biochemical literature and coupled with a model of the photophosphorylation processes. Flux map topologies for the hetero‐, auto‐, and mixotrophic modes of metabolism under conditions of optimal growth were determined and compared. The roles of important metabolic reactions such as the glyoxylate shunt and the transhydrogenase reaction were analyzed. We also theoretically evaluated the effect of gene deletions or additions on biomass yield and metabolic flux distributions.
Deactivation of Formate Dehydrogenase (FDH) in Solution and at Gas‐Liquid Interfaces
Authors: Bommarius Andreas S. , Karau Andreas 
Published: December 2005

AbstractEnzymes, increasingly important in the synthesis of fine chemicals and pharmaceutical intermediates, are often insufficiently stable under reacting conditions. We have investigated the stability, in homogeneous aqueous solution and at gas‐liquid interfaces, of formate dehydrogenase (FDH), important for cofactor regeneration, from Candida boidinii and overexpressed in E. coli. When exposed to mechanical stress, residual activity, [E]t/[E]0, and residual protein were found to scale proportionally with gas‐liquid surface area in the bubble column, verifying a surface‐driven process, and with time and total throughput in a gear pump, but did not seem to be influenced much by shear in a Couette viscometer. All FDH variants are deactivated by chaotropes but not kosmotropes: the first‐order deactivation constant kd correlates well with the Jones‐Dole coefficient B but not well with the surface tension increment Δσ of various concentrated ammonium salt solutions. This finding might provide guidance for focusing the search for quantitative theories of Hofmeister effects.
Noninvasive Diagnosis of a Single Cell with a Probe Beam
Authors: Wu Xing‐Zheng , Terada Satoshi 
Published: December 2005

AbstractIt is important to distinguish a living/dead cell in cell culture, especially in the regenerate medicine field including cell therapy, since those cells are usually in short supply and consequently the ex vivo culture process should be operated strictly. Conventional methods for distinguishing a living from a dead cell usually require labeling with a dye, which spoils the culture of the cell. Here we show a simple noninvasive method for diagnosing a dead or alive cell with a probe beam. If a cell is alive, the active transport of materials across the cell membrane causes a change of concentration gradients, and this change further induces a change of deflection of a probe beam passing through a vicinity of the cell membrane. If a cell is dead, no or little change in deflection of the probe beam is induced because no or little active materials movement across the cell membrane exists. The deflection of the probe beam is monitored, and judgment on whether a cell is dead or alive from the deflection signal agreed with the conventional decision.
Enhanced Production of Hydroperoxides by Immobilized Lipoxygenase in the Presence of Cyclodextrins
Authors: Pérez‐Gilabert Manuela , García‐Carmona Francisco 
Published: December 2005

AbstractThe advantages of the presence of cyclodextrins in a reaction catalyzed by immobilized lipoxygenase at neutral pH are reported for the first time. The steady‐state rate in the presence of β‐cyclodextrins was seven times higher than in control experiments using the same concentration of linoleic acid; furthermore the percentage of substrate conversion (and product accumulation) obtained in the presence of β‐cyclodextrins was higher than in the control assays. The optimum concentration of free linoleic acid coincided with the critical micellar concentration for linoleic acid at neutral pH. The operational stability of the immobilized enzyme increased in the presence of β‐cyclodextins, while an increase in the percentage of 13‐HPOD was also observed.
An Immobilized Biotin Ligase: Surface Display of Escherichia coli BirA on Saccharomycescerevisiae
Authors: Parthasarathy Ranganath , Bajaj Jitin , Boder Eric T. 
Published: December 2005

AbstractThe Escherichia coli biotin ligase enzyme BirA has been extensively used in recent years to generate site‐specifically biotinylated proteins via a biotin acceptor peptide tag. In the present study, BirA was displayed for the first time on the yeast Saccharomyces cerevisiae using the Aga1p‐Aga2p platform and assayed using a peptide‐tagged protein as the substrate. The enzyme is fully functional and resembles the soluble form in many of its properties, but the yeast‐displayed enzyme demonstrates stability and reusability on the time scale of weeks. Thus, the yeast‐displayed BirA system represents a facile and highly economical alternative for producing site‐specifically biotinylated proteins.
Contact stimulation of prostate cancer cell migration: the role of gap junctional coupling and migration stimulated by heterotypic cell‐to‐cell contacts in determination of the metastatic phenotype of Dunning rat prostate cancer cells
Authors: Miekus Katarzyna , Czernik Marta , Sroka Jolanta , Czyz Jarosław , Madeja Zbigniew 
Published: December 2005

Background information. Motile activity of tumour cells is regarded as a critical factor determining their metastatic potential. We have shown previously that contrary to the majority of normal cells, homotypic contacts between some tumour cells, among them low metastatic (AT‐2) and highly metastatic (MAT‐LyLu) rat prostate cancer cells, increase the speed of their movements. The aim of the present study was to determine the effect of heterotypic cell‐to‐cell contacts on the migration of rat prostate cancer cells differing in metastatic potential, and to correlate it with the intensity of homo‐ and heterologous gap junctional coupling.Results. MAT‐LyLu and AT‐2 cells moving on the surface of fibroblasts displayed significantly greater cell displacement than those moving on plastic substrata. This effect correlated with the polarization (contact guidance) and increased speed of cell movements. However, in contrast with the migration on plastic substrata, where MAT‐LyLu cells displayed considerably higher motility than AT‐2 cells, no differences between both cell lines were observed on the surface of fibroblasts. On the other hand, in contrast with AT‐2, Mat‐LyLu cells displayed extensive homologous coupling mediated by connexin43 and were able to couple with normal fibroblasts.Conclusion. Heterotypic contacts between migrating prostatic cancer cells and normal fibroblasts can strongly stimulate their migration during invasion; however, this effect does not correlate with the gap junctional coupling between cancer cells and normal fibroblasts.