bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water
Authors: Calvo-Bado Leo A. , Pettitt Tim R. , Parsons Nick , Petch Geoff M. , Morgan J. Alun W. , Whipps John M. 
Published: April 2003

ABSTRACTAn experimental slow sand filter (SSF) was constructed to study the spatial and temporal structure of a bacterial community suppressive to an oomycete plant pathogen,Phytophthora cryptogea. Passage of water through the mature sand column resulted in complete removal of zoospores of the plant pathogen. To monitor global changes in the microbial community, bacterial and fungal numbers were estimated on selective media, direct viable counts of fungal spores were made, and the ATP content was measured. PCR amplification of 16S rRNA genes and denaturing gradient gel electrophoresis (DGGE) were used to study the dynamics of the bacterial community in detail. The top layer (1 cm) of the SSF column was dominated by a variable and active microbial population, whereas the middle (50 cm) and bottom (80 cm) layers were dominated by less active and diverse bacterial populations. The major changes in the microbial populations occurred during the first week of filter operation, and these populations then remained to the end of the study. Spatial and temporal nonlinear mapping of the DGGE bands provided a useful visual representation of the similarities between SSF samples. According to the DGGE profile, less than 2% of the dominating bands present in the SSF column were represented in the culturable population. Sequence analysis of DGGE bands from all depths of the SSF column indicated that a range of bacteria were present, with 16S rRNA gene sequences similar to groups such asBacillus megaterium, Cytophaga,Desulfovibrio,Legionella,Rhodococcus rhodochrous,Sphingomonas, and an uncharacterized environmental clone. This study describes the characterization of the performance, and microbial composition, of SSFs used for the treatment of water for use in the horticultural industry. Utilization of naturally suppressive population of microorganisms either directly or by manipulation of the environment in an SSF may provide a more reproducible control method for the future.
A New Rate Law Describing Microbial Respiration
Authors: Jin Qusheng , Bethke Craig M. 
Published: April 2003

ABSTRACT
The rate of microbial respiration can be described by a rate law that gives the respiration rate as the product of a rate constant, biomass concentration, and three terms: one describing the kinetics of the electron-donating reaction, one for the kinetics of the electron-accepting reaction, and a thermodynamic term accounting for the energy available in the microbe's environment. The rate law, derived on the basis of chemiosmotic theory and nonlinear thermodynamics, is unique in that it accounts for both forward and reverse fluxes through the electron transport chain. Our analysis demonstrates how a microbe's respiration rate depends on the thermodynamic driving force, i.e., the net difference between the energy available from the environment and energy conserved as ATP. The rate laws commonly applied in microbiology, such as the Monod equation, are specific simplifications of the general law presented. The new rate law is significant because it affords the possibility of extrapolating in a rigorous manner from laboratory experiment to a broad range of natural conditions, including microbial growth where only limited energy is available. The rate law also provides a new explanation of threshold phenomena, which may reflect a thermodynamic equilibrium where the energy released by electron transfer balances that conserved by ADP phosphorylation.
Inactivation of Bacteria in Seawater by Low-Amperage Electric Current
Authors: Park Jong-Chul , Lee Min Sub , Lee Dong Hee , Park Bong Joo , Han Dong-Wook , Uzawa Masakazu , Takatori Kosuke 
Published: April 2003

ABSTRACT

Seawater used in mariculture has been suspected of being a potential source of infection. In this study, the lethal effects of low-amperage electric treatment on microorganisms were examined in natural seawater and in seawater inoculated with
Vibrio
parahaemolyticus
. In both cases, bacteria including
V
.
parahaemolyticus
in seawater were completely eliminated in 100 ms by a 0.5-A, 12-V direct current. Electron microscopic investigation of the electrically treated bacteria revealed substantial structural damage at the cellular level. In conclusion, our results indicate that low-amperage electric treatment is effective for rapid inactivation of microorganisms in seawater.
Análisis de la deliberación de jurados que varían en tamaño y regla de decisión
Authors: de Paul Velasco Pilar 
Published: March 2003

Se estudian los efectos del tamaño del jurado (doce o seis miembros) y de la regla de decisión (unanimidad o mayoría de dos tercios) en el proceso de interacción, analizando las deliberaciones mediante el Método de Observación de Bales. Asimismo, se analiza si las variaciones en tamaño y regla afectan al nivel de participación de los miembros durante la deliberación. Los resultados apoyan la existencia de un diferente estilo de deliberación en los jurados de mayor tamaño. Además, los miembros de jurados de menor tamaño participan en mayor medida, pero no existen diferencias significativas respecto a las variaciones en la regla de decisión.
Social representations of AIDS among Italian health care workers
Authors: Mannetti Lucia , Pierro Antonio 
Published: March 2003

The study investigates health care workers' representations of AIDS and its sufferers as a part of a larger research program aimed at providing a better understanding of the factors that affect health care workers' helping behaviour. 345 Italian health care workers from public hospitals were requested to write «the first things that came to their minds when thinking of AIDS and of AIDS sufferers». From Multiple Correspondence Analysis three principal axes emerged: the first one expresses a distinction between a view focused on ways of transmission and a view focused on the affective impact; the second one expresses a distinction between a view of AIDS as a serious danger and a view that stresses the media construction of the problem; the third one expresses a distinction between a purely medical view and an emphatic-emotional view. Contrary to previous results from research on the general public, in this case higher levels of scientific knowledge are not associated with less negative reactions toward AIDS sufferers.
Rates of spontaneous reactivation and aging of acetyicholinesterase in human erythrocytes after inhibition by organophosphorus pesticides
Authors: Mason H J , Sams C , Stevenson A J , Rawbone R 
Published: April 2003

The in vitro rates of spontaneous reactivation and aging in human erythrocyte acetylcholinesterase were studied after inhibition by a dimethoxy (RjR2) and diethoxy substituted (RjR2) organophosphate pesticide (OP) of general structure R1R2P(O)X. These have been compared with data for human plasma cholinesterase previously reported using a similar methodology. A significantly slower rate of aging for erythrocyte acetylcholinesterase was found compared to plasma cholinesterase, whether inhibited by dimethoxy or diethoxy substituted OPs. For diethoxy OPs the rate of spontaneous reactivation of the inhibited plasma enzyme was significantly slower than for the inhibited red cell enzyme. This acetylcholinesterase, and previously published plasma cholinesterase, data suggest that in practise a blood sample taken 30-40 h after significant acute OP exposure will still show inhibition in either plasma or erythrocyte cholinesterase when analysed, but that any inhibited plasma enzyme is more likely to be in the aged form. In contrast a substantial proportion of the erythrocyte acetylcholinesterase is found unaged and therefore sensitive to reactivation by oximes. Samples from an occupational exposure where depressions in plasma or erythrocyte cholinesterase activity from baseline measurements were reactivated ex vivo using the oxime 2-PAM support this hypothesis. These data also confirm that the plasma enzyme is a more sensitive than erythrocyte acetylcholinesterase as an indicator of OP exposure and thus the potential value of ex vivo oxime reactivation of erythrocyte acetylcholinesterase in a blood sample to indicate subclinical OP exposure may be limited. However, this study is too small to draw conclusions on the sensitivity of ex vivo oxime reactivation of acetylcholinesterase as a novel biomarker of excessive OP absorption. Given that there is a better relationship between anticholinergic symptoms and red cell acetylcholinesterase inhibition, and that the slower resynthesis rate of any aged or inhibited red cell enzyme may be interpretatively useful when venepuncture is delayed, it is suggested that red cell acetylcholinesterase activity does have a place in monitoring potential OP exposure.
Inhibitory effect of Emblica officinals on the in vivo clastogenicity of benzo alpyrene and acyclophosphamide in mice
Authors: Sharma N , Trikha P , Athar M , Raisuddin S 
Published: April 2003

Benzo [α] pyrene (B[α]P) and cyclophosphamide (CP) are potent carcinogens/mutagens. Effect of Emblica officinalis extract administration on the in vivo genotoxi-city of B[α]P and CP was studied using bone marrow chromosomal aberration and micronucleus induction tests in mice. Three doses (50,250 and 500mg/kgbodyweight) oftheplant extractwere administered orallyfor 7 consecutive days prior to the administration of single dose of mutagens (B[α]P 125 mg/kg oral; CP 40 mg/kg i.p.). It was found that administration of 250 and 500 mg/kg of E. officinalis extract significantly inhibited the genotoxi-city of B [α] P as well as CP in both the assay systems. Administration of 50 mg/kg of the plant extract had no inhibitory effect. Vitamin C, a major constituent of E. officinalis when administered at dose level of 9 mg/kg b.w. (the approx-imate estimated amount present in the highest dose of plant extract, i.e. 500 mg) for 7 days did inhibit chromosomal aberrations and micronuclei induction, but not in a significant manner. Effect of administration of the abovementioned effective doses (250 and 500 mg/kg oral for 7 days) of plant extract and vitamin C (9 mg/kg oral for 7 days) on the hepatic activation and detoxification enzymes was also studied. Significant induction in the levels of glutathione content (GSH) and of antioxidant and detoxification enzymes viz., glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S transferase (GST) resulted from plant extract treatment to animals. On the other hand, cytochrome P 450 level was significantly decreased in the plant-extract-treated animals. There was no significant change in cytochrome P 450, GSH contents and activities of enzymes on treatment with vitamin C. The data indicate that the possible mechanism of inhibition by plant extract is mediated by its modulatory effect on hepatic activation and disposition processes.
Cholinesterase activities determination in frozen blood samples: an improvement to the occupational monitoring in developing countries
Authors: Oliveira-Silva J J , Alves S R , Inacio A F , Meyer A , Sarcinelli P de N , Mattos R de C , Ferreira M de FA , Cunha J C , Moreira J C 
Published: April 2003

1 Studies were carried out on rural workers in Brazil to determine the decrease in the activity of plasma butyrylcholinesterase (BChE), erythrocyte cholinesterase (AChE) associated with exposure to organophosphorus pesticides (OP). The goal of this work is to help prevent injury to these workers. 2 In developing countries the distance between area of pesticide use and reference laboratories is a drawback for analytical techniques, since cholinesterase activity determinations require fresh blood samples. Field methodologies can be a useful alternative to laboratory tests, however they are not as sensitive as those found in laboratories. 3 The modification of Ellman's Method presented in this paper allows blood samples to be frozen and maintain enzymatic stability: 7 days for AChE and 3 days for BChE. The proposed method is also more sensitive than Ellman's Method Modified by Magnotti (EMMM). 4 The results suggest that the Ellman Method Modified by Oliveira-Silva (EMMOS) is valid for monitoring procedures. This method represents an important contribution to the process of monitoring OP exposures, since the evaluations no longer have to be conducted near the site of OP use.
The characterisation and uptake of paraquat in cultured baboon kidney proximal tubule cells (bPTC)
Authors: Machaalani R , Lazzaro V , Duggin G G 
Published: April 2003

A primary culture of baboon proximal tubule cells (bPTC) was prepared and characterised using LLC-PK1 cells of proximal tubule origin and MDCK cells of distal tubule origin, as positive and negative references, respectively. The proximal tubular origin of the bPTC was determined by morphological studies, immunoperoxidase staining and the expression of proximal tubule markers alkaline phosphatase and gammaglutamyltransferase. The hypothesis that paraquat (PQ) is transported by the bPTC was investigated. The cytotoxic threshold for PQ in these cells was determined and compared to the LLC-PK1 and MDCK cells. Furthermore, this study investigated the transport of the monovalent cation tetraethyl ammonium (TEA) and the polyvalent cation cimetidine in the bPTC and demonstrated their effect on the cellular uptake of PQ. The cytotoxic threshold of PQ in the bPTC, determined by cellular viability studies using the method of Trypan blue exclusion, is 0.05 mM at 2 h incubation. The LC50 after 24 his 76, 61 and 455 pM for the bPTC, LLC-PK1 and MDCK cells, respectively. This indicates that proximal tubule cells are more susceptible to PQ toxicity compared to distal tubule cells, which is consistent with clinical PQ toxicity where renal damage is found predominantly in the proximal renal tubules. The cations PQ and cimetidine were actively transported by the bPTC. The uptake of PQ (0.05 mM) commenced after 15 min whereas cimetidine (0.5 mM) uptake was evident after 2 min. Furthermore, cimetidine was shown to compete with PQ for uptake in the bPTC. Coincubating PQ (0.05 mM) and cimetidine (0.5 mM) for 60 min resulted in an approximate 50% decrease in PQ uptake. The cation TEA was not transported by the bPTC suggesting either a genetic mutation or complete absence of the transporter for TEA in the cells. The results suggest that PQ may be transported by the same cation transporter as cimetidine and not TEA, indicating PQ uptake in the bPTC to be via a polyvalent organic cation transporter.
Detoxification of organophosphates by A-esterases in human serum
Authors: Sams C , Mason H J 
Published: April 2003

1 In vitro detoxification of the organophosphate (OP) insecticides paraoxon, chlorpyrifos-oxon and malaoxon has been investigated in human serum. 2 Specific A-esterase activity to each OP substrate was measured in the serum of 100 individuals using established spectrophotometric methods for paraoxonase and chlorpyrifos-oxonase and a novel assay for malaoxonase activity. 3 Dose-effect inhibition of serum cholinesterase by the three OPs was measured in pooled human serum. Inhibition of calcium dependent A-esterases by addition of EDTA resulted in increased inhibition of cholinesterase at a given OP concentration. 4 Data from both the direct spectrophotometric measurement of A-esterase activity and inhibition of serum cholinesterase in the presence and absence of Aesterase activity indicated that human serum Aesterase catalysed detoxification of chlorpyrifosoxon4 paraoxon4 malaoxon. Our data also confirms the wide variation in potency to inhibit cholinesterase between the three OPs. 5 Malaoxonase activity in human serum does not appear to be polymorphic, however, there is large interindividual variation as has been previously found for other A-esterases. 6 This study has demonstrated two approaches to investigate the inter-individual variation towards specific OPs and the relative ability of human serum A-esterase to detoxify specific OP compounds.
The association between preand postnatal tobacco smoke exposure and allergic sensitization during early childhood
Authors: Kulig Michael , Luck Werner , Wahn Ulrich ,   Multicentre Allergy Study Group, Germany
Published: April 2003

Aim of our study was to investigate the effect of preand postnatal passive tobacco smoke exposure on the incidence of allergic sensitization. Patients and methods Specific sensitization to food, outdoor and indoor allergens was determined in 342 children at the age of 1, 2 and 3 years. Parents were asked about their smoking habit at the birth of their children, at 18 months and 3 years of age. Results Multivariate regression analysis indicated, that during the first 3 years of life, preand postnatally exposed children had a significantly higher risk for sensitization to food allergens compared to children never exposed to tobacco smoke exposure on specific sensitization could bedemonstrated. Conclusion During early childhood both preand postnatal tobacco smoke exposure has an adjuvant effect on allergic sensitization to food allergens.
Biological monitoring exposure of workers from plant producing carbon electrodes: quantification of benzo[a]pyrene DNA adducts in leukocytes, by a 32P-postlabelling method and an immunoassay
Authors: Arnould J P , Pfohl-Leszkowicz A , Bach V , Libert J P , Belegaud J 
Published: April 2003

The levels of benzo[a]pyrene were monitored for blood DNA-benzo[a]pyrene adducts in 17 workers from a plant producing carbon electrodes, with high exposure to benzo[a]pyrene (575-902-1149 ng m-3). Two different techniques, a 32P-postlabelling method and a competitive immunoassay using polyclonal antibodies obtained from rabbits immunised with DNA modified by benzo[a]pyrenetrans-7,8-dihydrodiol-9,10-epoxide were used. For each worker, urinary 1-hydroxypyrene, a potential indicator of exposure to polycyclic aromatic hydrocarbons, was measured. The effect of tobacco by urinary cotinine measurement was also considered. The postlabelling and immunoassay detection limits for DNA-benzo[a]pyrene adducts were respectively 0.15 and 10 fmol 50 ug-1 of DNA. The results obtained by the two methods demonstrated a good detection of DNA-benzo[a]pyrene adducts, but no direct relationship between the quantity of adducts and the concentration of benzo[a]pyrene in air-borne was noted in the studied plant. The levels of DNA-benzo[a]pyrene adducts obtained by immunoassay were significantly higher than those obtained by the 32P-postlabelling (P50.001). For several workers, variations due to professional or non professional factors must be taken into account in interpreting the results. In conclusion, the two methods used proved very efficient in determining DNA-benzo[a]pyrene adducts, and may be useful in monitoring human exposure to known and previously unidentified environmental genotoxic agents.
Preparation of Ordered Macroporous Sr0.5Sm0.5CoO3 as Cathode for Solid Oxide Fuel Cells
Authors: Chen Fanglin , Xia Changrong , Liu Meilin 
Published: April 2003

Abstract
Ordered macroporous Sr0.5Sm0.5CoO3 structrures with an average pore size of 140 nm have been prepared using close-packed arrangement of monodispersed polystyrene spheres as templates. A fuel cell using ordered macroporous Sr0.5Sm0.5CoO3 as the cathode, gadolinia-doped ceria (GDC) film as the electrolyte, and GDC–NiO as the anode generated maximum power densities of 150, 196 and 267 mW/cm2 at 500, 550 and 600 °C, respectively.
Photoisomerization of Persilyl-Substituted Silacyclopropene: Formation of Stable Persilyl-Substituted 1-Silaallene, and Its Reactivity
Authors: Ichinohe Masaaki , Tanaka Takashi , Sekiguchi Akira 
Published: April 2003

Abstract
Persilyl-substituted silacyclopropenes, (R3Si)2SiC2(SiMe3)2 (1a: R3Si = iPr3Si, 1b: R3Si = tBu2MeSi), were photochemically isomerized to 1-silaallene derivatives, (R3Si)2Si=C=C(SiMe3)2 2, at wavelengths longer than 340 nm. These compounds subsequently photoisomerized to acetylene derivatives, (R3Si)2(Me3Si)Si–C≡C–SiMe3 3, as a final product. The existence of 1-silaallene 2 was demonstrated spectroscopically as well as by a trapping reaction with water.
An Efficient Enantioselective Preparation of (S,S)-1,2-Bis(1-hydroxyalkyl)benzene
Authors: Asami Masatoshi , Wada Masaaki , Furuya Sanae 
Published: April 2003

Abstract
(S,S)-1,2-Bis(1-hydroxyalkyl)benzenes were obtained in &gt;99% ee’s with high diastereoselectivity by the enantioselective addition of dialkylzinc to (S)-2-[1-(4-methoxybenzyloxy)alkyl]benzaldehyde (86% ee) in the presence of a catalytic amount of (S)-2-(4-methylpiperazin-1-ylmethyl)indoline.
Direct Synthesis of MCM-41 Mesoporous Aluminosilicates Containing Au Nanoparticles in Aqueous Solution
Authors: Lin Hong-Ping , Chi Yu-Shan , Lin Jiunn-Nan , Mou Chung-Yuan , Wan Ben-Zu 
Published: April 2003

Abstract
A mesoporous MCM-41 aluminosilicate containing Au nanoparticles catalyst of high surface area and porosity has been conveniently prepared in a simple embedding approach.
Aqueous Solution-Based Ceramic Thin Film Deposition Using Organic Polymers with Amide Groups
Authors: Kozuka Hiromitsu , Kishimoto Tomoko 
Published: April 2003

Abstract
An aqueous solution-based dip-coating technique was presented for ceramic thin film deposition. Organic polymers with amide groups such as polyvinylpyrrolidone, polyvinylacetamide and polyacrylamide, incorporated in aqueous solutions of metal salts, were demonstrated to offer much better wetting of the substrates and gel film formability. Transparent, crack-free TiO2 and ZrO2 thin films of 0.07–0.1 µm in thickness could be obtained from aqueous solutions of Ti(SO4)2 and ZrCl2O, respectively, containing these organic polymers.
Reductive Aldol Reaction of a-Imino Esters Promoted by Titanium Tetraiodide: Selective Synthesis of α-Amino-β-hydroxyesters
Authors: Shimizu Makoto , Takeuchi Yuka , Sahara Tetsuya 
Published: April 2003

Abstract
Under the influence of titanium tetraiodide reductive aldol reaction of N-tosylimines, derived from ethyl glyoxylate, with aldehydes proceeded to give α-amino-β-hydroxyesters in good yields.
Rhodium(I)-Catalyzed Acylation of Alkyne with Acylsilane: Transformation of 5- or 6-Alkynoylsilane to α-Alkylidenecycloalkanone
Authors: Yamane Motoki , Amemiya Takuma , Narasaka Koichi 
Published: April 2003

Abstract
Rhodium(I)-catalyzed intramolecular acylation of alkynyl group proceeds by the use of acylsilanes having an alkynyl moiety. 5- and 6-Alkynoylsilanes are converted to α-alkylidenecycloalkanones by treatment with [RhCl(CO)2]2 in the presence of acetic acid via transmetallation between the acylsilane moiety and a rhodium(I) complex.
Synthesis and Transfection Capability of Multi-Functionalized Fullerene Polyamine
Authors: Isobe Hiroyuki , Tomita Naoki , Jinno Shigeki , Okayama Hiroto , Nakamura Eiichi 
Published: April 2003

Abstract
A new fullerene transfection reagent bearing multiple-functional groups has been synthesized by diastereoselective double cycloaddition reaction. The highly oxygenated reagent transfers extra-cellular DNA into mammalian cells with the efficiency comparable to that of a nor-analogue.
Synthesis of Bromohydrosilanes: Reactions of Hydrosilanes with CuBr2 in the Presence of CuI
Authors: Kunai Atsutaka , Ochi Takahiko , Iwata Arihiro , Ohshita Joji 
Published: April 2003

Abstract
Reactions of hydrosilanes, R4−nSiHn (R = alkyl or phenyl, n = 1–3), with 2 equiv of CuBr2 in the presence of a catalytic amount of CuI led to selective replacement of an H–Si bond with a Br–Si bond giving R3SiBr, R2SiHBr, or RSiH2Br, while treatment of R2SiH2 and RSiH3 with 4 equiv of the reagent produced R2SiBr2 and RSiHBr2, respectively. Similar reaction of Het2SiSiEt2H afforded Het2SiSiEt2Br.