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R Georges

Publications and source records attributed to R Georges.

At least 19 recordsLinked to original sources
PubMed2000

Uniform Supersonic Expansion for FTIR Absorption Spectroscopy: The nu(5) Band of (NO)(2) at 26 K.

A high-resolution Fourier transform interferometer (Bruker IFS 120 HR) was combined with a uniform supersonic expansion produced by means of axisymmetric Laval nozzles. The geometry profile of the nozzle enabled us to work under precise thermodynamic and kinetic conditions. The effect of the cooling rate of different nozzles on cluster nucleation is illustrated. The experimental sensitivity was tested by recording the nu(5) band of (NO)(2) at 26 K. Copyright 2000 Academic Press.

Journal Article↗
PubMed1998

High-Resolution FTIR Spectroscopy Using a Jet: Sampling the Rovibrational Spectrum of 12CH4

We have recorded high-resolution absorption spectra of 12CH4 cooled in a jet, using a Fourier transform interferometer. The expected nuclear spin symmetry conservation in the jet is exhibited from data recorded around 3000 cm-1 showing the relative intensity of the lines starting from the J" = 2 para and ortho levels. Spectra recorded around 4300 cm-1 are used to validate existing rovibrational parameters. Spectra recorded around 6000 cm-1 allow new rovibrational assignments to be performed in the N = 4 polyad. In particular, lines in the nu1 + nu3 band are identified for the first time. Copyright 1998 Academic Press. Copyright 1998Academic Press

Journal Article↗
PubMed1997

High-Resolution Spectroscopic Investigation of nu16 in trans-1,2-Dichloroethane

We report on the first detailed rovibrational analysis in 1,2-dichloroethane. It concerns the a-type nu16 absorption band of gaseous trans-1,2-dichloroethane at 1232 cm-1, which we have recorded using a Fourier transform interferometer, under room temperature and jet-cooled experimental conditions. The rotational analysis of the almost diatomic-like prominent R and P structures in nu16 is performed for trans-1,2-12C2H435Cl2 and trans-1,2-12C2H435Cl37Cl. The nuclear spin statistics is discussed for various isotopomers and isomers of 1,2-dichloroethane. The complex absorption pattern observed at the band center is tentatively assigned in terms of overlapping Q branches, arising from fundamental bands involving different isotopomers in natural abundance (with 35Cl and 37Cl), and from related hot bands involving the three lowest vibrational modes in the molecule, nu6, nu10, and nu18. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1996

Gene Replacement Strategies for Lung Cancer.

Advances in our understanding of the molecular genetics of cancer present an opportunity to develop prevention and treatment strategies based on the reversal of specific genetic lesions. This strategy is analogous to the classic concept of gene therapy for replacement of defective or nonfunctioning genes. The gene families implicated in carcinogenesis include dominant oncogenes and tumor suppressor genes. Regional administration of viral vectors expressing wildtype p53 and antisense K-ras prevents tumor growth for tumors with the specific genetic lesions in orthotopic tumor models and mediates regression of large established tumors. These studies provide a rationale for a new clinical protocol recently approved by the National Institutes of Health Recombinant DNA Advisory Committee and Food and Drug Administration to replace a defective p53 gene with intratumor injection of recombinant retrovirus expressing wild-type p53 or elimination of activated K-ras by expression of antisense K-ras messenger RNA. If these agents are efficacious, their lack of toxicity may provide a sufficiently high therapeutic index such that they could be used as an adjuvant to surgery to treat patients with earlier stages of cancer or as prevention for second primary cancers for individuals with genetic abnormalities in premalignant lesions. Although much research needs to be done, the possibility of specific gene targeting with a high therapeutic index makes this a promising area of investigation.

Journal Article↗
PubMed1992

Bronchogenic carcinoma in patients with pulmonary histiocytosis X.

Five cases of bronchogenic carcinoma were observed among 93 patients with pulmonary histiocytosis X (Hx). Mean age at the time of diagnosis of Hx was 42 years; on the average, cancer occurred 10.5 years later. All patients were smokers and continued to smoke heavily at the time of diagnosis of cancer. Comparison of the five cases associating Hx and lung carcinoma with a group of 88 control patients suffering from Hx alone suggested that smoking played the predominant role in the pathogenesis of cancer. In fact, among the four patients with Hx and carcinoma older than 45 years, tobacco consumption was significantly greater (64.7 +/- 37 pack-year, mean +/- SD) than that of the 15 control patients of the same age with only Hx (40.8 +/- 11.6, p less than 0.01). In light of this good correlation, the diagnosis of Hx strongly advocates stopping tobacco smoking and long-term medical follow-up.

Adolescent↗
PubMed1991

[CD8+T-cell lymphocytic alveolitis in sarcoidosis. 4 cases].

We report 4 cases of histologically proven sarcoidosis with lymphocytic alveolitis. The T CD4+/T CD8+ ratio was below 1 in the bronchoalveolar lavage fluid. Since there was no clinical and paraclinical evidence of extrinsic allergic alveolitis or HIV infection, and since 3 of the patients were nonsmokers and the 4th one smoked moderately, we considered that the T CD8+ lymphocytic alveolitis was related to the sarcoidosis. In 3 patients the presence of mediastinal adenopathy suggested that sarcoidosis was of recent onset. The fact that T CD4+/T CD8+ ratio was normal in blood indicated that T CD8+ lymphocytes were predominant only in the lung. Thus, the finding of T CD8+ lymphocytic alveolitis should not exclude a diagnosis of sarcoidosis.

Adult↗
PubMed1991

Glucose, K+, and albumin concentrations in the alveolar milieu of normal humans and pulmonary sarcoidosis patients.

Some properties of the alveolar epithelial barrier during transalveolar transport of water and solutes were studied in normal humans and patients with sarcoidosis by means of the transalveolar capillary concentration gradients of various solutes. A total of 9 normal control subjects (Group A) and 60 sarcoidosis patients, 52 with an evolving disease (Group B) and 8 recovered (Group C), underwent bronchoalveolar lavage (BAL). The second aliquot of fluid was used to measure urea, glucose, potassium, and albumin, which were also investigated in plasma. Urea was used to determine the volume of alveolar epithelial lining fluid (AELF volume). Results are expressed as the ratio of solute concentration in AELF over that in plasma (A/P ratio). In Group A there were clear concentration gradients of glucose, potassium, and albumin between the AELF and plasma, as the A/P ratios of glucose, potassium, and albumin were 0.02 +/- 0.006 (mean +/- SEM), 3.2 +/- 0.34, and 0.04 +/- 0.008, respectively. In Group B the A/P ratios of glucose (0.21 +/- 0.02, p less than 0.001) and albumin (0.17 +/- 0.02, p less than 0.001) were significantly increased but that of potassium remained unchanged (2.9 +/- 0.2). The A/P ratios of these various solutes were independent of chest x-ray typing. The albumin but not the glucose A/P ratio was correlated with the percentage of lymphocytes recovered from BAL (p less than 0.02); however, there was no correlation between the albumin A/P ratio and the CD4+/CD8+ T lymphocyte ratio. In group C there was a striking contrast between the albumin A/P ratio, which was normal, and the glucose A/P ratio, which was clearly elevated despite a normal lymphocyte count.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗