29 research outputs found

    Close Packing of Atoms, Geometric Frustration and the Formation of Heterogeneous States in Crystals

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    To describe structural peculiarities in inhomogeneous media caused by the tendency to the close packing of atoms a formalism based on the using of the Riemann geometry methods (which were successfully applied lately to the description of structures of quasicrystals and glasses) is developed. Basing on this formalism we find in particular the criterion of stability of precipitates of the Frank-Kasper phases in metallic systems. The nature of the ''rhenium effect'' in W-Re alloys is discussed.Comment: 14 pages, RevTex, 2 PostScript figure

    Conceptual approaches to cerebral blood flow correction in postmenopausal women with arterial hypertension

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    Aim. To assess cerebral blood flow and cholesterol (CH) metabolism in postmenopausal women with arterial hypertension (AH); to evaluate dynamics of cerebral blood flow and lipid profile during 6-month antihypertensive and hypolipidemic therapy. Material and methods. Postmenopausal women (n=47) with Stage I-II AH were examined. Leading clinical symptoms were explained by cerebrovascular pathology. All participants were divided into two groups: moexipril monotherapy (7.5-15 mg/d; n=15) and fosinopril monotherapy (10-20 mg/d; n=15). Women with dyslipidemia were administered atorvastatin, 10 mg/d: 10 patients in moexipril group, and 7 in fosinopril group. At baseline and 6 months later, Doppler ultrasound and lipoprotein profile assessment were performed in all participants. Results. At baseline, increased systolic blood flow velocity (S), decreased pulse index (PI), and increased cerebral vascular resistance index (RI) were observed in hypertensive women, comparing to age-specific normal levels. Six-month antihypertensive therapy was associated with S decrease, PI increase, and RI reduction, without any significant difference in cerebral hemodynamics parameters between two groups. At the same time, positive dynamics was more manifested in combined antihypertensive and hypolipidemic treatment. In these patients, cerebral hemodynamics improvement was combined with improvements in lipid profile and quality of life. Conclusion. In women with long-term AH duration, cerebral hemodynamics is typically disturbed. Combined antihypertensive and hypolipidemic therapy has the greatest beneficial effect on cerebral perfusion

    PHARMACOLOGICAL CORRECTION OF CEREBRAL BLOOD FLOW DISTURBANCES IN WOMEN WITH ARTERIAL HYPERTENSION IN POSTMENOPAUSE

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    Aim: to study cerebral blood flow and cholesterol metabolism in menopausal women with arterial hypertension (AH); to evaluate dynamics of cerebral blood flow parameters and plasma lipid concentrations in these patients during 6-month antihypertensive and hypolipidemic therapy.Material and methods: 24 women with AH of I and II grade were examined. They were in postmenopausal period of life during 7,1±0,5 years. At the beginning of the study all women were prescribed moexipril as monotherapy, daily dose 7,5 – 15 mg. Patients with initial dislipidemia were prescribed lipid reducing drug atorvastatin in 10mg daily dose additionally to the antihypertensive therapy. Therefore all the patients were divided into two groups: I – monoteraphy with moexipril (13 people), II – combined therapy with moexipril and atorvastatin (11 people). At the beginning of the study and after 6 months all the patients passed through ultrasonic Dopplerography of vessels of head and neck, rheoencephalography, their lipoproteidogrammes were studied.Results: During 6-month therapy all the patients showed proved decrease in systolic and diastolic blood pressure, also positive dynamics of neuropsychological status, improvement in cerebral blood flow according to the results of Dopplerography of vessels and rheoencephalography. Normalization of plasma lipid spectrum was noted. More significant positive changes in cerebral hemodynamic parameters and plasma lipid spectrum were observed in patients, who received combined therapy with antihypertensive and lipid reducing drugs.Conclusion: Deterioration of cerebral hemodynamics is typical for women with long-lasting AH. The most positive influence on cerebral perfusion was received due to combined therapy with moexipril and atorvastatin
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