Biomedical subjects

R Souda

Publications and source records attributed to R Souda.

At least 19 recordsLinked to original sources

PubMed2004

Ionization and solvation of HCl adsorbed on the D2O-ice surface.

The interaction of HCl with the D(2)O-ice surface has been investigated in the temperature range 15-200 K by utilizing time-of-flight secondary ion mass spectroscopy, temperature-programmed desorption, and x-ray photoelectron spectroscopy. The intensities of sputtered H(+)(D(2)O) and Cl(-) ions (the H(+) ions) are increased (decreased) markedly above 40 K due to the hydrogen bond formation between the HCl and D(2)O molecules. The HCl molecules which form ionic hydrates undergo H/D exchange at 110-140 K and a considerable fraction of them dissolves into the bulk above 140 K. The neutral hydrates of HCl should coexist as evidenced by the desorption of HCl above 170 K. They are incorporated completely in the D(2)O layer up to 140 K. The HCl molecules embedded in the thick D(2)O layer dissolve into the bulk, and the ionic hydrate tends to segregate to the surface above 150 K.

Journal Article↗

PubMed2004

Interactions of D2O with methane and fluoromethane surfaces.

TOF-SIMS is used to investigate the interactions between D2O and hydrophobic molecules, such as CH4, CH3F, CH2F2, CHF3, and CF4, at cryogenic temperatures (15 K). By irradiation with a 1.5-keV He+ beam, the D(+)(D2O)n ions are ejected efficiently from the D2O nanoclusters physisorbed on the CF4 layer due to Coulomb explosion: the ion yields are by about two orders of magnitude higher than those from a thick D2O layer via the kinetic sputtering. The D(+)(D2O)n yields decrease on the CHnF(4-n) layer with increasing the number of the C-H group. This is because the Coulombic fission is quenched due to the delocalization of valence holes through the C-H...H-C and C-H...D2O contacts. A pure D2O film is hardly grown on the CH4 layer as a consequence of intermixing whereas the D2O molecules basically adsorb on the surfaces of fluoromethanes, suggesting the attractive (water-repellent) interactions in the C-H...D2O (C-F...D2O) contacts. The C-H...O bond behaves like a conventional O-H...O hydrogen bond as far as the collision-induced proton transfer reaction is concerned.

Journal Article↗

PubMed2000

Predictors of improvement in FEV1 (forced expiratory volume in 1s) after lung volume reduction surgery.

We evaluated various preoperative and operative factors to identify the predictors of improvement in forced expiratory volume in 1s (FEV1) after lung volume reduction surgery (LVRS). Fifty-eight emphysema patients received bilateral LVRS either via a sternotomy (n = 53) or by thoracoscopy (n = 5). The patients were divided into the following two groups: group I (n = 17), patients whose FEV1 improved by less than 20%; group II (n = 41), patients whose FEV1 improved by more than or equal to 20%. The preoperative factors (age, degree of dyspnea, oxygen use, steroid use, pulmonary function test, arterial blood gas, pulmonary hemodynamics, 6-min walking distance) and operative factors (removed lung weight, number of staplers) were both similar between the two groups. Upper lobe type emphysema was more frequently seen in group II and the average improvement in FEV1 was significantly better in the patients with upper lobe type emphysema (62.8% +/- 8.5%) than lower lobe type (36.9% +/- 7.6%) and mixed type (35.5% +/- 6.5%), P < 0.01. Severe pleural adhesion was more frequently found in group I and the average improvement in FEV1 was also significantly lower in patients with severe pleural adhesion (19.8% +/- 6.4%) than mild-to-moderate adhesion (46.8% +/- 5.3%) and no-to-minimal adhesion (62.3% +/- 10.4%), P < 0.01. These results lead us to conclude that upper lobe type emphysema may thus be a predictor of better FEV1 improvement while severe pleural adhesion is considered to be a predictor of a poorer FEV1 improvement after bilateral LVRS.

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PubMed1998

Bilateral lung volume reduction surgery via median sternotomy for severe pulmonary emphysema.

BACKGROUND: Lung volume reduction surgery either via sternotomy or by thoracoscopy has been demonstrated to be effective for selected emphysema patients in North America and Europe. The present study summarizes short-term results of bilateral lung volume reduction performed via median sternotomy for the first consecutive 39 patients with severe diffuse emphysema in Okayama, Japan, from July 1995 to February 1997. METHODS: There were 35 men and 4 women, and the age range was 54 to 74 years with a mean age of 65 years. All were former heavy smokers and none of them had alpha1-antitrypsin deficiency. Only 9 patients (23%) showed a bilateral upper lobe pattern of emphysema. The operation was done through a median sternotomy, and the most emphysematous portions were excised bilaterally with a linear stapling device fitted with strips of bovine pericardium to prevent air leakage. RESULTS: No operative death was encountered. The first 33 patients completed 3-month follow-up assessment, and their mean forced expiratory volume in 1 second had improved by 41% from 735 mL to 1,037 mL. Other parameters of pulmonary function tests, arterial blood gas analysis, 6-minute walking distance, and dyspnea scale also had improved significantly. These improvements lasted for at least a year. CONCLUSIONS: Bilateral lung volume reduction surgery via median sternotomy is a safe and effective procedure for selected severe emphysema patients. Although the pattern of emphysema might be different between countries, the results in Japanese patients were similar to those previously reported in North American and European patients.

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PubMed1996