Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Nature ; 537(7621): 515-517, 2016 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-27487219

RESUMEN

Remote observations of the asteroid (1) Ceres from ground- and space-based telescopes have provided its approximate density and shape, leading to a range of models for the interior of Ceres, from homogeneous to fully differentiated. A previously missing parameter that can place a strong constraint on the interior of Ceres is its moment of inertia, which requires the measurement of its gravitational variation together with either precession rate or a validated assumption of hydrostatic equilibrium. However, Earth-based remote observations cannot measure gravity variations and the magnitude of the precession rate is too small to be detected. Here we report gravity and shape measurements of Ceres obtained from the Dawn spacecraft, showing that it is in hydrostatic equilibrium with its inferred normalized mean moment of inertia of 0.37. These data show that Ceres is a partially differentiated body, with a rocky core overlaid by a volatile-rich shell, as predicted in some studies. Furthermore, we show that the gravity signal is strongly suppressed compared to that predicted by the topographic variation. This indicates that Ceres is isostatically compensated, such that topographic highs are supported by displacement of a denser interior. In contrast to the asteroid (4) Vesta, this strong compensation points to the presence of a lower-viscosity layer at depth, probably reflecting a thermal rather than compositional gradient. To further investigate the interior structure, we assume a two-layer model for the interior of Ceres with a core density of 2,460-2,900 kilograms per cubic metre (that is, composed of CI and CM chondrites), which yields an outer-shell thickness of 70-190 kilometres. The density of this outer shell is 1,680-1,950 kilograms per cubic metre, indicating a mixture of volatiles and denser materials such as silicates and salts. Although the gravity and shape data confirm that the interior of Ceres evolved thermally, its partially differentiated interior indicates an evolution more complex than has been envisioned for mid-sized (less than 1,000 kilometres across) ice-rich rocky bodies.

2.
Ter Arkh ; 93(8): 841-852, 2021 Aug 15.
Artículo en Ruso | MEDLINE | ID: mdl-36286877

RESUMEN

Treatment of inflammatory bowel diseases IBD (Crohns disease, ulcerative colitis) is aimed at achieving clinical, endoscopic and histological remission, minimizing surgical complications, and ensuring a normal quality of life. However, the use of medical treatment is potentially associated with various adverse events, among which infectious complications, malignant neoplasms, as well as myelotoxicity, hepatotoxicity, skin lesions and others. The risk of side effects depends on the type of drug therapy (5-aminosalicylates, thiopurines, biologicals, etc.), the duration of treatment, the presence of extra-intestinal manifestations, etc. The article provides an overview of data on both the effectiveness and frequency of various side effects of the main classes of drugs in IBD, presents methods of investigation which can predict the effectiveness and development of side effects, the implementation of which can be considered as a variant of personalized therapy in IBD.


Asunto(s)
Colitis Ulcerosa , Enfermedad de Crohn , Enfermedades Inflamatorias del Intestino , Humanos , Calidad de Vida , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Enfermedades Inflamatorias del Intestino/complicaciones , Colitis Ulcerosa/tratamiento farmacológico , Colitis Ulcerosa/complicaciones , Enfermedad de Crohn/tratamiento farmacológico , Administración de la Seguridad
3.
Klin Lab Diagn ; 60(4): 23-6, 39, 2015 Apr.
Artículo en Ruso | MEDLINE | ID: mdl-26189287

RESUMEN

The endothelium dysfunction takes leading place in pathogenesis of development of cardiovascular diseases. The circulating endothelium cells of peripheral blood can act as a direct cell marker of damage and remodeling of endothelium. The study was carried out to develop a new approach to diagnose of endothelium dysfunction by force of determination of number of circulating endothelium cells using flow cytometry technique and to apply determination of circulating endothelium cells for evaluation of risk of development of ischemic heart disease in women of young and middle age. The study embraced 62 female patients with angiography confirmed ischemic heart disease, exertional angina pectoris at the level of functional class I-II (mean age 51 ± 6 years) and 49 women without anamnesis of ischemic heart disease (mean age 52 ± 9 years). The occurrence of more than three circulating endothelium cells by 3 x 105 leukocytes in peripheral blood increases relative risk of development of ischemic heart disease up to 4 times in women of young and middle age and risk of development of acute myocardial infarction up to 8 times in women with ischemic heart disease. The study demonstrated possibility to apply flow cytometry technique to quantitatively specify circulating endothelium cells in peripheral blood and forecast risk of development of ischemic heart disease in women of young and middle age depending on level of circulating endothelium cells.


Asunto(s)
Angina de Pecho , Células Endoteliales , Endotelio Vascular , Citometría de Flujo/métodos , Isquemia Miocárdica , Adulto , Anciano , Angina de Pecho/sangre , Angina de Pecho/patología , Células Endoteliales/metabolismo , Células Endoteliales/patología , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Femenino , Humanos , Persona de Mediana Edad , Isquemia Miocárdica/sangre , Isquemia Miocárdica/patología
4.
Klin Lab Diagn ; (4): 30-2, 2013 Apr.
Artículo en Ruso | MEDLINE | ID: mdl-23984552

RESUMEN

The article presents the results of clinical economic analysis providing the evaluation of implementation of immunologic examination of patients with chronic infectious inflammatory diseases. To calculate the clinical economic indicators the factor costs and indirect costs were determined in case of immunologic examination and without examination according the data of prospective (80 patients) and retrospective study (500 outpatient cards). To evaluate the significance of approach based on immunologic examination methods the percentage of patients with relapse-free period was calculated. The clinical economic evaluation of methods of diagnostic and treatment made it possible to determine economic advantages of application of immunologic methods of examination independently of localization of chronic torpid process and to assess relationship between costs of immunologic methods of examination and effectiveness of applied treatment.


Asunto(s)
Enfermedad Crónica/economía , Análisis Costo-Beneficio , Infecciones/economía , Humanos , Inmunidad , Infecciones/inmunología , Estudios Prospectivos , Estudios Retrospectivos
5.
Klin Lab Diagn ; (11): 22-4, 2011 Nov.
Artículo en Ruso | MEDLINE | ID: mdl-22312911

RESUMEN

The evaluation of prevalence and intensity of vitamin D3 deficiency in preschoolers and schoolchildren residing in Moscow and St. Petersburg was implemented. It is established that 63.6% of all Moscow children and adolescents of and 43% of St. Petersburg minors live in conditions of vitamin D3 deficiency. Regardless of the residence region, the vitamin D3 deficiency prevalence is more typical for schoolchildren as compared with preschoolers. The higher prevalence of vitamin D3 deficiency demands to change the policy of vitamin D3 supply among minors.


Asunto(s)
Colecalciferol/sangre , Deficiencia de Vitamina D/epidemiología , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Moscú/epidemiología , Prevalencia , Federación de Rusia/epidemiología
6.
Nat Commun ; 7: 12257, 2016 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-27459197

RESUMEN

Asteroids provide fundamental clues to the formation and evolution of planetesimals. Collisional models based on the depletion of the primordial main belt of asteroids predict 10-15 craters >400 km should have formed on Ceres, the largest object between Mars and Jupiter, over the last 4.55 Gyr. Likewise, an extrapolation from the asteroid Vesta would require at least 6-7 such basins. However, Ceres' surface appears devoid of impact craters >∼280 km. Here, we show a significant depletion of cerean craters down to 100-150 km in diameter. The overall scarcity of recognizable large craters is incompatible with collisional models, even in the case of a late implantation of Ceres in the main belt, a possibility raised by the presence of ammoniated phyllosilicates. Our results indicate that a significant population of large craters has been obliterated, implying that long-wavelength topography viscously relaxed or that Ceres experienced protracted widespread resurfacing.

7.
Science ; 353(6303)2016 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-27701088

RESUMEN

Analysis of Dawn spacecraft Framing Camera image data allows evaluation of the topography and geomorphology of features on the surface of Ceres. The dwarf planet is dominated by numerous craters, but other features are also common. Linear structures include both those associated with impact craters and those that do not appear to have any correlation to an impact event. Abundant lobate flows are identified, and numerous domical features are found at a range of scales. Features suggestive of near-surface ice, cryomagmatism, and cryovolcanism have been identified. Although spectroscopic analysis has currently detected surface water ice at only one location on Ceres, the identification of these potentially ice-related features suggests that there may be at least some ice in localized regions in the crust.

8.
Science ; 353(6303)2016 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-27701089

RESUMEN

Thermochemical models have predicted that Ceres, is to some extent, differentiated and should have an icy crust with few or no impact craters. We present observations by the Dawn spacecraft that reveal a heavily cratered surface, a heterogeneous crater distribution, and an apparent absence of large craters. The morphology of some impact craters is consistent with ice in the subsurface, which might have favored relaxation, yet large unrelaxed craters are also present. Numerous craters exhibit polygonal shapes, terraces, flowlike features, slumping, smooth deposits, and bright spots. Crater morphology and simple-to-complex crater transition diameters indicate that the crust of Ceres is neither purely icy nor rocky. By dating a smooth region associated with the Kerwan crater, we determined absolute model ages (AMAs) of 550 million and 720 million years, depending on the applied chronology model.

9.
Radiats Biol Radioecol ; 42(2): 194-9, 2002.
Artículo en Ruso | MEDLINE | ID: mdl-12004618

RESUMEN

The aim of the paper is to investigate accumulation of artificial radionuclides by the Yenisei River aquatic plants collected in the area affected by the activity of the Mining-and-Chemical Combine (Zheleznogorsk) from 1997 to 2000. The samples of aquatic plants were of four species: Potamogeton lucens, Fontinalis antipyretica, Elodea canadensis, and Ceratophyllum demersum. The gamma-spectrometric analysis of the samples of aquatic plants for artificial radionuclides revealed a wide spectrum of long-half-life and short-half-life radionuclides. Radionuclides of activation origin were found in the aquatic plants taken both near the Combine and 200 km down of it. The data obtained suggest that the cooling water of the operating reactor is still being released into the Yenisei. The radiochemical analysis of aquatic plants revealed strontium and plutonium isotopes. Among the aquatic plants, the highest concentration factors for the principal radionuclides were recorded in Fontinalis antipyretica (water moss).


Asunto(s)
Industria Química , Minería , Reactores Nucleares , Plantas/química , Radioisótopos/análisis , Contaminantes Radiactivos del Agua/análisis , Residuos Industriales , Plutonio/análisis , Radioquímica , Siberia , Espectrometría gamma , Radioisótopos de Estroncio/análisis
10.
Ter Arkh ; 72(4): 58-62, 2000.
Artículo en Ruso | MEDLINE | ID: mdl-10833802

RESUMEN

AIM: To study changes in pulmonary hypertension in patients with isolated mitral valvular defects of rheumatic etiology after surgical correction and in the early postoperative period. MATERIALS AND METHODS: Central hemodynamics in heart chamber probing before operation and intraoperatively were measured in 98 patients with rheumatic mitral defects (41 males, 57 females, mean age 39.5 +/- 8.74). Manometry before and after the defect correction, intraoperative catheterization (cath. Swan-Ganz) for hemodynamics 24-h follow-up were made. RESULTS: After valvular defect correction 90(91%) patients had residual pulmonary hypertension, stage II-III in 41%. CONCLUSION: Patients operated for rheumatic heart disease complicated by pulmonary hypertension often suffer from residual pulmonary hypertension. This requires pharmacological correction.


Asunto(s)
Hipertensión Pulmonar/fisiopatología , Válvula Mitral , Cardiopatía Reumática/cirugía , Adulto , Velocidad del Flujo Sanguíneo , Presión Sanguínea , Cateterismo Cardíaco , Cateterismo , Femenino , Enfermedades de las Válvulas Cardíacas/complicaciones , Enfermedades de las Válvulas Cardíacas/cirugía , Implantación de Prótesis de Válvulas Cardíacas , Humanos , Hipertensión Pulmonar/etiología , Masculino , Monitoreo Intraoperatorio , Circulación Pulmonar , Presión Esfenoidal Pulmonar , Cardiopatía Reumática/complicaciones , Resultado del Tratamiento
11.
Klin Med (Mosk) ; 78(2): 40-2, 2000.
Artículo en Ruso | MEDLINE | ID: mdl-10723151

RESUMEN

A pilot trial of efficiency of enalapril maleate in the treatment of residual pulmonary hypertension was made in 22 patients operated for rheumatic mitral valve defects. Degree I, II and III of pulmonary hypertension was registered in 5, 13 and 4 patients, respectively. Thus, the patients had NYHA functional classes III and IV (22.7 and 77.3%, respectively. Enalapril given for 6 months in a mean daily dose 12.3 +/- 1.57 mg/m2 (5-30 mg a day) normalized pressure in the pulmonary artery in 18.2% of patients. 50% of patients showed hypertension degree I, only one female retained hypertension degree III. To the end of the treatment the functional classes were the following: II--in 68.2%, III--in 27.3% and IV--in 4.5%.


Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Enalapril/uso terapéutico , Hipertensión Pulmonar/tratamiento farmacológico , Válvula Mitral , Cardiopatía Reumática/cirugía , Adulto , Femenino , Enfermedades de las Válvulas Cardíacas/complicaciones , Enfermedades de las Válvulas Cardíacas/cirugía , Humanos , Hipertensión Pulmonar/etiología , Masculino , Persona de Mediana Edad , Presión Esfenoidal Pulmonar/efectos de los fármacos , Cardiopatía Reumática/complicaciones , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA