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R Mayol

Publications and source records attributed to R Mayol.

13 recordsLinked to original sources
PubMed2003

Bound states of 3He at the edge of a 4He drop on a cesium surface.

We show that small amounts of 3He atoms, added to a 4He drop deposited on a flat cesium surface at zero temperature, populate bound states localized at the contact line. These edge states show up for drops large enough to develop well defined surface and bulk regions together with a contact line, and they are structurally different from the well-known Andreev states that appear at the free surface and at the liquid-solid interface of films. We illustrate the one-body density of 3He in a drop with 1000 4He atoms, and show that for a sufficiently large number of impurities the density profiles spread beyond the edge, coating both the curved drop surface and its flat base and eventually isolating it from the substrate.

Journal Article↗
PubMed2001

Quantized vortices in mixed 3He-4He drops.

Using density functional theory, we investigate the structure of mixed (3)He(N3)-(4)He(N4) droplets with an embedded impurity (Xe atom or HCN molecule) which pins a quantized vortex line. We find that the dopant+vortex+(4)He(N4) complex, which in a previous work [F. Dalfovo et al., Phys. Rev. Lett. 85, 1028 (2000)] was found to be energetically stable below a critical size N(cr), is robust against the addition of 3He. While 3He atoms are distributed along the vortex line and on the surface of the 4He drop, the impurity is mostly coated by 4He atoms. Results for N4 = 500 and a number of 3He atoms ranging from 0 to 100 are presented, and the binding energy of the dopant to the vortex line is determined.

Journal Article↗
PubMed2000

Pinning of quantized vortices in helium drops by dopant atoms and molecules

Using a density functional method, we investigate the properties of liquid 4He droplets doped with atoms (Ne and Xe) and molecules ( SF6 and hydrogen cyanide). We consider the case of droplets having a quantized vortex pinned to the dopant. A liquid-drop formula is proposed that accurately describes the total energy of the complex and allows one to extrapolate the density functional results to large N. For a given impurity, we find that the formation of a dopant+vortex+(4)He(N) complex is energetically favored below a critical size N(cr). Our results support the possibility to observe quantized vortices in helium droplets by means of spectroscopic techniques.

Journal Article↗
PubMed1986

A comparison of celiprolol and chlorthalidone in hypertensive patients with reversible bronchial obstruction.

The objective of this study was to evaluate the effects of celiprolol, a new beta-blocking drug, on the clinical condition and pulmonary function of hypertensive patients with reversible bronchial obstruction. Celiprolol was compared with chlorthalidone, an antihypertensive drug without known effect on bronchial tone. The study consisted of a 4-week placebo run-in period and a 12-week titration period in which the dose of both drugs was increased at 4-week intervals if blood pressure was not reduced adequately. The doses of celiprolol were 200, 400, or 600 mg once daily; those for chlorthalidone 12.5, 25, or 37.5 mg once daily. Entry criteria were a diastolic blood pressure between 90 and 115 mg Hg, and FEV-1 between 40% and 80% of predicted value, increasing by 15% or more after salbutamol, and a need for occasional bronchodilator therapy. Prophylactic medication for asthma was given in constant dosage for a month before the study and throughout the study. Preliminary results on 66 patients demonstrate that neither drug had a clinically significant effect on FEV-1, FEF 25-75, or FVC. Clinical variables were not significantly changed by either drug: the average monthly asthma attacks fell from 18 to 13 with celiprolol and from 11 to 7 with chlorthalidone. FEF was reduced by more than 50% in two patients on celiprolol and three on chlorthalidone. Monthly asthma attacks increased by more than 100% in five patients on celiprolol and four on chlorthalidone. Thus, preliminary results are unable to demonstrate adverse effects from celiprolol in patients with asthma and hypertension.

Adrenergic beta-Antagonists↗
PubMed1986

A placebo-controlled double-blind multicenter study of celiprolol in the treatment of mild and moderate hypertension.

This study evaluated the 24-h antihypertensive effect of single daily doses of celiprolol, a beta-1 adrenoceptor antagonist. Patients with supine diastolic BP between 95 and 114 mm Hg started on placebo or celiprolol 200 mg daily for 2 weeks; non-responders received 400 mg daily for 2 weeks and then 600 mg daily for another 2 weeks. Response was defined as a reduction of diastolic BP to 90 mm Hg or below. One hundred ninety patients were evaluated for efficacy, 114 in the celiprolol group and 76 in the placebo group, 84 men and 106 women, mean age 52 years. Blood pressure after 6 weeks fell from 165/103 to 149/92 on celiprolol and from 162/103 to 157/97 on placebo. The fall in systolic and diastolic BP after celiprolol is statistically different (p less than 0.001) from that after placebo. The pulse rate was reduced to a similar extent by the two treatments. The percent of patients with supine diastolic BP either reduced by at least 10 mm Hg or to 90 mm Hg or below, was 66% after celiprolol and 38% after placebo (p less than 0.001). The incidence of adverse reactions was comparable in the two groups: 31% during celiprolol, 25% during placebo. The most frequent reactions observed in both groups were gastrointestinal symptoms, dizziness, fatigue, headache. In conclusion, celiprolol proved to be a safe and effective beta-blocker in the treatment of mild and moderate hypertension.

Adrenergic beta-Antagonists↗
PubMed1986

Celiprolol in the treatment of exercise induced angina pectoris.

A multicenter, double-blind placebo controlled study was designed to examine the efficacy of celiprolol in exercise induced angina pectoris. The study consisted of a 4-week placebo run-in period, 6-week titration, 4-week maintenance, 2-week tapering and a 2-week placebo run-out period. Entry criteria were a history of stable angina with chest pain and 1 mm ST segment depression between 3 and 12 min after start of treadmill exercise stress test. Patients started with celiprolol 200 mg daily for 2 weeks; non-responders received 400 mg daily for 2 weeks and then if necessary 600 mg daily for another 2 weeks. A 20% increase over baseline in exercise stress test to onset of angina was considered a response. Ninety-two patients were evaluated, 54 in the celiprolol group and 38 in the placebo group; 63 men and 29 women, mean age 57 years. The celiprolol group was significantly different from placebo after 6 weeks. In particular, exercise time increased by 4.3 min (placebo increased by 0.3 min), ST segment depression reduced by 0.4 mm, notwithstanding the increase in exercise time (placebo increased by 0.2 mm), maximum exercise heart rate reduced by 6 beats per min (placebo increased by 3 beats per min), maximum exercise systolic BP reduced by 14 mm Hg (placebo decreased by 1 mm Hg). The therapeutic success rate based on a 20% increase of exercise time was 85% after celiprolol and zero after placebo. Reduction in weekly angina attacks and nitroglycerin consumption was from 8 to 3 after celiprolol and from 9 to 6 after placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1980

Mechanism by which antibodies to non-AgB antigens mediate rejection of rat leukaemia cells.

The August and Hooded rat strains are compatible at the major histocompatibility locus (both are AgB5 or Rtlc). Antisera against the minor histocompatibility antigens of Hooded rats were raised by immunizing August rats with grafts of tumours or normal tissue. Such antisera, if transferred to normal unimmunized August rats, cause them to reject i.v. administered Hooded rat leukemia (HRL) cells within a few hours, and X-irradiated August rats, for whom a graft of HRL is lethal, can survive indefinitely if pretreated with the antiserum. The distribution of 125I-labelled HRL cells in the tissues of August rats was followed at times after their injection, and it was found that, in the presence of antiserum, i.v. administered leukaemic cells are rapidly destroyed in the liver and spleen. The active component of the antiserum is IgG antibody, and its action is independent of the lytic elements of complement. Antibody-mediated splenic and hepatic clearance of the leukaemia cells is unaffected by total-body X-irradiation but reduced by treating the rats with colloidal carbon. The data are consistent with the hypothesis that the rejection of HRL across the histocompatibility barrier studied is, in the presence of antibody, effected by immunophagocytosis.

Acute Disease↗
PubMed1977

Ia antigens on murine thymocytes: detection by cellular radioimmunoassay.

An indirect radioimmunoassay was used to detect Ia antigenic determinants at the cell surface of thymic and splenic cells. An A.TH anti-A.TL serum was used as a source of anti-Ia antibodies which could bind to H-2a or H-2k target cells. Bound alloantibody was then detected with 125I anti-mouse IgG1 antibody. This assay system revealed Ia antigens on thymic T cells which are not usually detectable by cytotoxicity assays, and has the potential for quantitative measurement of such determinants on cells. Critical adsorption studies were performed to confirm that Ia antigens were in fact the targets of the alloantiserum tested.

Animals↗