Search Results - (Author, Cooperation:G. Dumenil)

2011-02-12

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Bacterial Adhesion ; Cell Line, Tumor ; Epithelial Cells/microbiology ; Fimbriae Proteins/chemistry/*metabolism ; Fimbriae, Bacterial/chemistry/*metabolism ; Gene Expression Regulation, Bacterial ; Glycerol/metabolism ; Humans ; Models, Molecular ; Neisseria meningitidis/genetics/growth & development/*pathogenicity ; Phosphorylation ; Phosphotransferases/*genetics/*metabolism ; *Protein Processing, Post-Translational ; Transcription, Genetic

0022-0531

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Economics

Electronic Resource

0022-0531

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Economics

Electronic Resource

0954-349X

business cycle ; classics ; competition ; dynamic model ; historical tendencies ; profit rate

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Economics

Electronic Resource

0954-349X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Economics

Electronic Resource

1432-0614

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Summary Crude oil was degraded by a mixed bacterial community grown in continuous culture on sea water. The fermentation process included an emulsification step prior to the introduction of the substrate in the reactor, with external cell recycling by a tangential-flow filtration system. Optimization of the fermentation technique was achieved by using the surface response methodology (Doehlert experimental design). Besides reducing the number of experiments, this approach allowed optimal experimental conditions to be chosen, for the particular goal: percent degradation of crude oil (80%), biomass (7.6 g·l-1) and degradation rate (0.73 g·l-1·h-1). This biodegradation process could be used as a tool to fight against pollutions by petroleum products.

Electronic Resource

0167-2681

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Economics

Electronic Resource

0165-1161

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

0165-1161

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

0931-8658

Economics

0931-8658

Economics

0309-166X

Economics

0309-166X

Economics

0309-166X

Economics

0303-8300

Sociology

1432-0614

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Summary A mixed culture of bacteria MS1 capable of growth on methanol as its sole carbon-energy source was isolated by continuous culture with a minimum mineral salts medium and without asepsis. This bacterial association is composed of four Gram-negative bacterial strains which we identified. The respective numerical proportions of each microorganism are stable in time. The properties, and specially the stability of the continuous culture process have been studied with respect to substrate yield, biomass and productivity.

Electronic Resource

1432-0614

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Summary The bioconversion from DL-Homoserine to L-Threonine byEnterobacter cloacae resting-cells is directed by various parameters: concentration in cells, in homoserine, in glucose, temperature, shaking, pH, and time. Some of them, such as temperature, shaking, and pH were determined during preliminary tests. In order to consider the reciprocal effect of the other parameters, we applied an experimental scheme based on the simultaneous variation of all parameters of the process. The method of factorial designs is based on the choice of an experimental field for which we make a matrix of the experiments. The measured result is the yield of L-Threonine produced in relation to L-Homoserine employed. The computational interpretation of the results gives the levels of significance of every parameter and the direction of the variation needed to improve the yield. This method permits us to obtain information which may be interpreted immediately, with a reduced number of experiments.

Electronic Resource

1432-0614

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Summary The Simplex method of optimization was applied to the bioconversion of DL-Homoserine into L-Threonine byEnterobacter cloacae resting-cells in a 2 1 fermentor. The three parameters used (cell concentration C, L-Homoserine concentration H and agitation A) form the basic system for the construction of the Simplex. The effect of time on the evolution of the reaction is observed by sampling; the measured results for each experiment are given at the end of the same period. The conditions of the reaction are marked in a system of orthogonal axes, in the form of vectors $$\vec v_1 ,\vec v_2 ,\vec v_3 $$ and $$\vec v_4 $$ . These 4 vectors define in the axes system a regular tetrahedron one vertex of which is the junction of the origin of the axes; the representative points of the experiments are to be found at the vertices of the tetrahedron. In order to find the area of space where the yield will be optimum, we eliminate the vertex of the tetrahedron giving the poorest result, and we substitute a new point obtained by taking the symetrical of the former in relation to the plane formed by the 3 other points. This manner of conducting the experiments will lead necessarly to the optimum of the process with the greatest economy of time and a minimum of tests.

Electronic Resource

1432-1246

Key words Antineoplastic agents ; Chemical degradation ; Mutagenicity tests

Springer Online Journal Archives 1860-2000

Medicine

Abstract  Handling genotoxic compounds commonly used in cancer chemotherapy generates contaminated wastes that require decontamination before disposal. Chemical methods are an alternative and/or a complement to incineration for the treatment of wastes and spills. As part of a program initiated by the International Agency for Research on Cancer (IARC), three chemical methods readily available in the hospital environment, viz sodium hypochlorite (NaOCl, 5.25%), hydrogen peroxide (H2O2,?30%) and Fenton reagent (FeCl2, 2H2O; 0.3 g in 10 ml H2O2, 30%), were tested for the degradation of three alkylating agents (cyclophosphamide, CP; ifosfamide, IF, and melphalan). Pharmaceutical preparations corresponding to the most highly concentrated administration solutions in either NaCl (0.9%) or dextrose (5%) were inactivated by oxidation volume/volume with each of the methods for at least 1 h. The efficiency of degradation was monitored by high-pressure liquid chromatography. The mutagenicity of the degradation residues was tested by means of the Ames test using tester strains of Salmonella typhimurium TA 97a, TA 98, TA 100 and TA 102 with and without an exogenous metabolic activation system. Complete disappearance of CP was observed after 1 h with all degradation methods. However, direct mutagens were generated by the Fenton oxidation technique in the presence of dextrose (5%). IF was completely degraded by the Fenton reagent and NaOCl methods. No mutagenic residues were detected after 1 h of treatment with the Fenton technique, and after 3 h with the NaOCl method. Direct-acting mutagens remained after the H2O2 treatment in the presence of dextrose (5%). Complete degradation of melphalan was achieved in 1 h by each of the three methods, and no mutagenic residues were produced by any of the treatments. The use of NaOCl (5.25%) proved the most efficient system for degradation of the three alkylating agents.

Electronic Resource

1432-1246

Occupational exposure ; Cytostatic drugs ; Ames assay ; Urine mutagenicity ; Smoking

Springer Online Journal Archives 1860-2000

Medicine

Abstract A study was undertaken to evaluate the urine mutagenicity of 63 individuals working in four hospital departments. The exposed group included 38 subjects who were exposed to various cytostatic drugs and/or contaminated material from treated patients. The control group included 25 individuals of the hospital personnel. Urine mutagenicity was monitored by the Ames test using tester strains TA 98 + S9 Mix and TA 102 — S9 Mix. Urine samples were collected before and after the working periods. A total of 29/116 (25%) urine samples were mutagenic for either strain. Among the mutagenic samples, 24/29 were mutagenic for tester strain TA 98 exclusively. No significant correlation could be found between occupational exposure to cytostatic drugs and urine mutagenicity evaluated by the strain TA 98 + S9 Mix. Smoking was the main environmental factor that modulated urine mutagenicity with TA 98. Three subjects in the exposed group had mutagenic urine samples at the end of the working period with strain TA 102 — S9 Mix. This mutagenicity was related to occupational exposure to cisplatin. In the control group, one individual had mutagenic samples before and after the working period. Assessing occupational exposure to cytostatic drugs with strain TA 102 requires additional studies to determine environmental mutagens which can be detected by this strain.

Electronic Resource