joyce merrill valdes
20784914
The effect of rifampicin on the in vitro activity of cefpirome or ceftazidime in combination with aminoglycosides against Pseudomonas aeruginosa.
The in vitro activity of cefpirome and ceftazidime when combined with aminoglycosides (gentamicin, amikacin, and tobramycin) in the presence and in the absence of rifampicin was evaluated against 32 isolates of Pseudomonas aeruginosa by two methods. Agar dilution susceptibilities demonstrated a marked reduction in synergy (FIC less than or equal to 0.5) when rifampicin was added to the combination. Synergy rates decreased from 59.4 84.4% without to 3.1 9.4% with the addition of rifampicin. In contrast, kill curve tests performed on two P. aeruginosa strains demonstrated synergy at 24 h when rifampicin was added to cefpirome, ceftazidime, gentamicin or a beta lactam agent plus gentamicin combination. The addition of rifampicin to the combinations of cefpirome or ceftazidime plus gentamicin achieved a 2 log10 lower bacterial count at 24 h than that of the beta lactam and gentamicin combination alone. When rifampicin was added to the combination cefpirome or ceftazidime plus gentamicin at different times during incubation, a greater bactericidal effect was observed when rifampicin was added at 0 and 1 h of incubation than when added later. No antagonism was observed with rifampicin when used in combination with beta lactam agents and/or aminoglycosides.
The Journal of antimicrobial chemotherapy
Joaquin Mario Valdes Aldona L Baltch Russell P Smith Mark C Hammer William J Ritz
37765178
Comparative therapy with cefpirome alone and in combination with rifampin and/or gentamicin against a disseminated Pseudomonas aeruginosa infection in leukopenic mice.
Treatment of disseminated Pseudomonas aeruginosa infection in leukopenic mice was evaluated using cefpirome alone and in combination with gentamicin and/or rifampin. Mice were made leukopenic with cyclophosphamide and infected through a skin incision with an inoculum of 1250 organisms (13 LD50) Antibiotics were administered subcutaneously for 48 h. Although the addition of cefpirome to gentamicin and/or rifampin improved survival significantly at 48 h compared with untreated controls (84.6% 100% vs. 38.5% therapy with these combinations did not improve survival significantly from that achieved with cefpirome alone. Quantitative blood and tissue (liver, spleen, kidney, lung) cultures in mice treated with cefpirome alone or including rifampin were lower than in infected controls or groups receiving therapy that excluded cefpirome. Highest counts were observed in mice receiving cefpirome plus gentamicin. Except for the cefpirome plus gentamicin group, which demonstrated areas of acute tubular necrosis, the cefpirome group had less tissue pathology than infected controls.
The Journal of infectious diseases
Joaquin Mario Valdes Aldona L Baltch Russell P Smith Mary Ann Franke William J Ritz S Williams Phyllis B Michelsen J K Singh
95849759
Spectrum analysis of surface roughness signals obtained with the scanning tunneling microscope
Abstract Power spectra of published STM records concerning surface roughness measurements are considered. Preliminary results indicate preponderance of very low frequency components. A 1/ f 3 like power spectrum frequency dependence is observed in the log log representation.
J Valdes E E Lobbe Marta Porfiri
98203187
Possible evidence of single electron tunneling with the scanning tunneling microscope at room temperature
Contradictory previous results concerning I V curves for metal insulator metal tip to sample tunnel junctions are pointed out. In this paper we present experimental data acquired in ambient conditions, tested with different measuring methods, showing stable I V curves, nonlinear at least for tunneling voltages higher as 100 mV. We also confirm the scanning tunneling microscopy (STM) behavior as a diode by mixing two microwave signals of different frequencies in the same way as a normal diode connected instead of the tip sample junction does. The shape of the I V curves that we obtained for low applied voltages in ambient conditions resemble those reported by other authors at helium temperature as giving evidence of a single electron tunneling (SET) current between tip and surface. Adopting the SET model, the voltage difference between shifted hypothetical asymptotes would imply here a dynamical capacitance C between tip and sample of the order of 10 19 F, which is a value low enough as to fulfill with the condition required for SET effects to become evident at room temperature. Finally we report some of the difficulties in a direct detection of the SET frequency, if any, in order to realize a dc quantum standard by using the STM set up at room temperature.Contradictory previous results concerning I V curves for metal insulator metal tip to sample tunnel junctions are pointed out. In this paper we present experimental data acquired in ambient conditions, tested with different measuring methods, showing stable I V curves, nonlinear at least for tunneling voltages higher as 100 mV. We also confirm the scanning tunneling microscopy (STM) behavior as a diode by mixing two microwave signals of different frequencies in the same way as a normal diode connected instead of the tip sample junction does. The shape of the I V curves that we obtained for low applied voltages in ambient conditions resemble those reported by other authors at helium temperature as giving evidence of a single electron tunneling (SET) current between tip and surface. Adopting the SET model, the voltage difference between shifted hypothetical asymptotes would imply here a dynamical capacitance C between tip and sample of the order of 10 19 F, which is a value low enough as to fulfill with the.
J Valdes Efrosini Choleva
158206888
Radio in foreign language education
Joyce Merrill Valdes Robert James Nelson Richard E Wood
7715689
In vitro susceptibilities of gram positive bacteria to cefpirome, vancomycin, isepamicin and gentamicin, singly and in combination.
The Journal of antimicrobial chemotherapy
Joaquin Mario Valdes Aldona L Baltch Russell P Smith William J Ritz
146875919
Culture Bound: Bridging the Cultural Gap in Language Teaching@@Culture, Proficiency, and Control in FL Teaching
Linda M Crawford-Lange Joyce Merrill Valdes Guenter G Pfister Yvonne Poser
55906938
Culture bound bridging the cultural gap in language teaching
Preface Part I. Language, Thought, and Culture: 1. Language and thought Franz Boas 2. Culture and the written language Robert B. Kaplan 3. Acculturation and mind William R. Acton and Judith Walker de Felix 4. Learning a second culture H. Douglas Brown Part II. Cultural Differences and Similarities: 5. How to compare two cultures Robert Lado 6. Kinesics and cross cultural understanding Gennelle G. Mortain 7. Intercultural differences and communicative approaches to foreign language teaching in the Third World Karl Heinz Osterloh 8. So near the United States' John C. Condon 9. Cultural clues to the Middle Eastern student Orin D. Parker and Educational Services Staff, AFME 10. XANADU 'A miracle of rare device' the teaching of English in China Alan Maley 11. Compliments in cross cultural perspective Nessa Wolfson Part III. Classroom Applications: 12. Culture in the classroom Nelson Brooks 13. Newspapers: vehicles for teaching ESOL with a cultural focus Charles H. Blatchford 14. Culture in literature Joyce Merrill Valdes 15. English language teaching from an intercultural perspective Stephen C. Dunnett, Fraida Dubin and Amy Lezberg 16. An argument for culture analysis in the second language classroom George H. Hughes 17. Culture bump and beyond Carol M. Archer 18. The culture test Rebecca M. Valette Bibliography Index.
Joyce Merrill Valdes
143955114
CULTURE BOUND: BRIDGING THE CULTURAL GAP IN LANGUAGE TEACHING Joyce Merrill Valdes Ed. Cambridge: Cambridge University Press, 1986. Pp. xi 222.
Margie S Berns
144019241
Book Review Culture Bound
Ian Martin