RESUMEN
BSTS epitaxial thin film topological insulators were grown using the MBE technique on two different types of substrates i.e., Si (111) and SiC/graphene with Bi0.7Sb1.6Te1.8Se0.9 and Bi0.9Sb1.5Te1.8Se1.1, respectively. The crystallographic properties of BSTS films were investigated via X-ray diffraction, which showed the strongest reflections from the (0 0 l) facets corresponding to the rhombohedral phase. Superior epitaxial growth, homogeneous thickness, smooth surfaces, and larger unit cell parameters were observed for the films grown on the Si substrate. Polarization dependent Raman spectroscopy showed a weak appearance of the Ag mode in cross--polarized geometry. In contrast, a strong Eg mode was observed in both parallel and cross-polarized geometries which correspond to the rhombohedral crystal symmetry of BSTS films. A redshift of Ag and Eg modes was observed in the Raman spectra of BSTS films grown on the Si substrate, compared to those on SiC/graphene, which was directly associated with the unit cell parameter and composition of the films. Raman spectra showed four fundamental modes with asymmetric line shape, and deconvolution of the peaks resulted in additional modes in both the BSTS thin films. The sum of relative ratios of linewidths of fundamental modes (Ag and Eg) of BSTS films grown on Si substrate was lower, indicating a more ordered structure with lower contribution of defects as compared to BSTS film grown on SiC/graphene substrate.
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To address a challenging problem of super-resolution terahertz (THz) endoscopy, in this paper, an antiresonant hollow-core waveguide was coupled with a sapphire solid immersion lens (SIL), aimed at subwavelength confinement of guided mode. The waveguide is formed by a polytetrafluoroethylene (PTFE)-coated sapphire tube, the geometry of which was optimized to ensure high optical performance. SIL was judiciously designed, fabricated of bulk sapphire crystal, and then mounted at the output waveguide end. Study of the field intensity distributions at the shadow side of the waveguide-SIL system revealed the focal spot diameter of ≃0.2λ at the wavelength of λ = 500 µm. It agrees with numerical predictions, overcomes the Abbe diffraction limit, and justifies super-resolution capabilities of our endoscope.
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Among the most significant challenges presented to modern medicine is the problem of cognitive disorders. The relevance of her research is determined by the wide spread of disorders of the higher cortical functions, their significant negative impact on the quality of life of patients, as well as high economic costs on the part of the state and the patient's relatives aimed at organizing medical, diagnostic and rehabilitation processes. The main cause of cognitive impairment in the elderly is Alzheimer's disease. Currently, the criteria for the diagnosis of this nosological form have been developed and are widely used in practice. However, it should be noted that their use is most effective if the patient has a detailed clinical picture, at the stage of dementia. In addition, they provide for the study of biomarkers in a number of cases in the cerebrospinal fluid or using positron emission tomography, which presents certain technical difficulties. Especially significant problems arise in the pre-dement stages. This situation dictates the need to search for new promising diagnostic methods that will have high sensitivity and specificity, as well as the possibility of application in the early stages of Alzheimer's disease, including in outpatient settings. The article provides information about modern methods of computer neuroimaging, discusses the research directions of individual biomarkers, and also shows the prospects for using diagnostic test panels developed on the basis of graphene biosensors, taking into account the latest achievements of nanotechnology and their integration into medical science.
Asunto(s)
Enfermedad de Alzheimer , Grafito , Anciano , Enfermedad de Alzheimer/diagnóstico , Biomarcadores , Pruebas Diagnósticas de Rutina , Progresión de la Enfermedad , Diagnóstico Precoz , Femenino , Humanos , Calidad de VidaRESUMEN
Resistivity, ρ(T), and magnetoresistance (MR) are investigated in graphene grown on SiC (0 0 0 1), at temperatures between T ~ 4-85 K in pulsed magnetic fields of B up to 30 T. According to the Raman spectroscopy and Kelvin-probe microscopy data, the material is a single-layer graphene containing ~20% double-layer islands with a submicron scale and relatively high amount of intrinsic defects. The dependence of ρ(T) exhibits a minimum at temperature T m ~ 30 K. The low-field Hall data have yielded a high electron concentration, n R ≈ 1.4 × 1013 cm-2 connected to intrinsic defects, and a mobility value of µ H ~ 300 cm2 (Vs)-1 weakly depending on T. Analysis of the Shubnikov-de Haas oscillations of MR, observed between B ~ 10-30 T, permitted to establish existence of the Berry phase ß ≈ 0.55 and the cyclotron mass, m c ≈ 0.07 (in units of the free electron mass) close to expected values for the single-layer graphene, respectively. MR at 4.2 K is negative up to B ~ 9 T, exhibiting a minimum near 3 T. Analysis of MR within the whole range of B = 0-10 T below the onset of the SdH effect has revealed three contributions, connected to (i) the classical MR effect, (ii) the weak localization, and (iii) the electron-electron interaction. Analysis of the ρ(T) dependence has confirmed the presence of the contributions (ii) and (iii), revealing a high importance of the electron-electron scattering. As a result, characteristic relaxation times were obtained; an important role of the spin-orbit interaction in the material has been demonstrated, too.
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We report a giant thermal shift of 2.1 MHz/K related to the excited-state zero-field splitting in the silicon vacancy centers in 4H silicon carbide. It is obtained from the indirect observation of the optically detected magnetic resonance in the excited state using the ground state as an ancilla. Alternatively, relative variations of the zero-field splitting for small temperature differences can be detected without application of radiofrequency fields, by simply monitoring the photoluminescence intensity in the vicinity of the level anticrossing. This effect results in an all-optical thermometry technique with temperature sensitivity of 100 mK/Hz(1/2) for a detection volume of approximately 10(-6) mm(3). In contrast, the zero-field splitting in the ground state does not reveal detectable temperature shift. Using these properties, an integrated magnetic field and temperature sensor can be implemented on the same center.
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The role of Campylobacter pylori (CP) in the development of chronic gastritis and ulcero-erosive lesions in 76 patients with liver cirrhosis of various etiology is studied. The incidence of CP bacteriosis in liver cirrhosis was 47.3% and the incidence of CP detection by bacteriological methods was not dependent on the cirrhosis etiology. The incidence of CP detection depended on the chronic gastritis activity and the presence of ulcero-erosive lesions. Hypochlorhydria is one of the important factors favouring CP colonization in liver cirrhosis. DE-NOL can be recommended for the treatment of chronic active gastritis and ulcero-erosive lesions.
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Helicobacter pylori/aislamiento & purificación , Cirrosis Hepática/microbiología , Adolescente , Adulto , Anciano , Biopsia con Aguja , Duodeno/microbiología , Duodeno/patología , Femenino , Infecciones por Helicobacter/complicaciones , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Humanos , Hígado/microbiología , Hígado/patología , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Cirrosis Hepática Alcohólica/etiología , Cirrosis Hepática Alcohólica/microbiología , Cirrosis Hepática Alcohólica/patología , Cirrosis Hepática Biliar/etiología , Cirrosis Hepática Biliar/microbiología , Cirrosis Hepática Biliar/patología , Masculino , Persona de Mediana Edad , Estómago/microbiología , Estómago/patologíaRESUMEN
A rare case of a diffuse pulmonary leiomyomatosis in a female aged 38 is described. Alveolar proteinosis was suspected clinically. Diagnosis of the diffuse pulmonary leiomyomatosis was established at the autopsy basing on the pattern or morphological changes.
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Leiomioma/patología , Neoplasias Pulmonares/patología , Adulto , Biopsia , Broncoscopía , Femenino , Humanos , Leiomioma/diagnóstico , Pulmón/diagnóstico por imagen , Pulmón/patología , Neoplasias Pulmonares/diagnóstico , Metástasis Linfática , RadiografíaRESUMEN
Functional and morphological state of the stomach and duodenum was studied in 98 patients with liver cirrhosis. Hepatogenous ulcer was revealed in 21.7 per cent of the patients with alcoholic and in 25 per cent of those with viral liver cirrhosis. A specific feature of the condition was the development of ulcer in reduced gastric acid production and its asymptomatic course. The incidence of gastric and duodenal affections in liver cirrhosis was significantly higher in pronounced portal hypertension. Study of the portal blood flow with Doppler ultrasonography can reveal the risk group (patients with pronounced portal hypertension) which has high probability of the development of erosion-ulcerous lesions. These patients require obligatory medical checkups with gastric and duodenal endoscopy 2-3 times a year.
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Hepatitis Alcohólica/complicaciones , Hepatitis Viral Humana/complicaciones , Hipertensión Portal/complicaciones , Cirrosis Hepática/complicaciones , Úlcera Péptica/etiología , Adulto , Ácido Gástrico/metabolismo , Mucosa Gástrica/metabolismo , Hepatitis Alcohólica/fisiopatología , Hepatitis Viral Humana/fisiopatología , Humanos , Hipertensión Portal/fisiopatología , Cirrosis Hepática/fisiopatología , Persona de Mediana EdadAsunto(s)
Hepatopatías/patología , Hígado/patología , Sarcoidosis/patología , Adulto , Biopsia , Femenino , Humanos , Persona de Mediana EdadRESUMEN
The paper is concerned with the results of a long-term study with clinicomorphological correlations of 86 patients with alcoholic glomerulonephritis (GN), i. e. 12% of all morphologically verified cases of primary GN. GN clinical features in alcoholism were painless microhematuria, moderate hyperuricemia, frequent combination with the alcoholic involvement of the other organs and the elevated blood serum IgA level. An important diagnostic sign in alcoholic GN was a positive clinicolaboratory time course in abstinence. A morphological study showed prevalence of mesangioproliferative GN with deposits containing IgA and C3, often with a noticeable tubulointerstitial component and fibroplastic glomerular transformation. The accumulation of podocytes and nephrocytes of intermediate filaments in the cytoplasm should be regarded as an important morphological feature of alcoholic GN. An unfavorable course of alcoholic GN with an outcome into chronic renal failure was observed in 35% of the patients. Prognostically unfavorable signs were the age under 40, the presence of considerable proteinuria (over 1 g/day), the nephrotic syndrome, the detection of the glomerular immune complexes, a tubulointerstitial component, fibroplastic transformation of mesangioproliferative nephritis as well as the detection of mesangiocapillary, diffuse fibroplastic and extracapillary nephritis.
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Alcoholismo/patología , Glomerulonefritis/patología , Adulto , Alcoholismo/complicaciones , Alcoholismo/mortalidad , Complejo Antígeno-Anticuerpo/análisis , Complemento C3/análisis , Femenino , Mesangio Glomerular/inmunología , Mesangio Glomerular/ultraestructura , Glomerulonefritis/etiología , Glomerulonefritis/mortalidad , Glomerulonefritis por IGA/etiología , Glomerulonefritis por IGA/mortalidad , Glomerulonefritis por IGA/patología , Humanos , Inmunoglobulinas/análisis , Masculino , Persona de Mediana Edad , PronósticoRESUMEN
Alcoholic microangiopathy was studied on the biopsy material from kidneys, skin and salivary glands of alcoholic patients by means of histochemical, immunohistochemical and electron-microscopic methods. Its formation is mainly caused by the direct action of ethanol on microcirculatory vessels. Alcohol-induced microangiopathy is morphologically manifested by the accumulation of intermediate filaments in the cytoplasm of endotheliocytes and perivascular infiltrate macrophages. The expression of pathological changes in the cytoskeleton is reduced due to the abstinence from alcohol. Glomerulonephritis in alcoholic patients, that can be considered as a peculiar manifestation of alcoholic microangiopathy, is immunocomplex with predominance in these immune complexes of IgA in combination with IgG and C3 complement fraction. Morphologically it is characterized by the accumulation of intermediate filaments in the cytoplasm of podocytes, mesangiocytes, nephrocytes and some endothelial cells, as well as early and quick formation of fibroplastic transformation and cirrhosis of the kidney.
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Alcoholismo/patología , Microcirculación/patología , Adulto , Atrofia , Humanos , Riñón/irrigación sanguínea , Masculino , Microcirculación/ultraestructura , Microscopía Electrónica , Persona de Mediana Edad , Glándulas Salivales Menores/irrigación sanguínea , Piel/irrigación sanguíneaRESUMEN
Separation of the alcoholic disease into a special nosological entity is founded on the basis of a clinico-morphological analysis. It is suggested to distinguish hepatic, gastric, pancreatic, cardiac, pulmonary and renal clinico-anatomical forms of the alcoholic disease that are most frequently observed in the therapeutic clinics. The most characteristic signs of the ethanol effect ("morphological markers") are as a rule observed in the exacerbation of the disease. They are as follows: alcoholic hyalin in hepatocytes and accumulation of intermediate filaments in the epithelial and mesenchymal cells. Pathology of the cytoskeleton is a morphological expression of the affected protein metabolism. Apart from the disturbance of the protein metabolism, the metabolism of lipids is damaged as well, this being manifested in the accumulation of fat inclusions in the cytoplasm of the different organ cells. Leucocytes and macrophages of the exudate in the alcoholic disease possess the signs of the functional insufficiency thus confirming the state of the immunodeficiency in alcoholics.
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Alcoholismo/patología , Enfermedad Aguda , Alcoholismo/inmunología , Cardiomiopatía Alcohólica/patología , Enfermedad Crónica , Gastritis/inducido químicamente , Gastritis/patología , Glomerulonefritis/inducido químicamente , Glomerulonefritis/patología , Humanos , Hialina/inmunología , Riñón/patología , Hígado/inmunología , Hígado/patología , Hepatopatías Alcohólicas/inmunología , Hepatopatías Alcohólicas/patología , Pulmón/patología , Enfermedades Pulmonares/inducido químicamente , Enfermedades Pulmonares/patología , Miocardio/patología , Páncreas/patología , Pancreatitis/inducido químicamente , Pancreatitis/patología , Pielonefritis/inducido químicamente , Pielonefritis/patología , Estómago/patología , Úlcera Gástrica/inducido químicamente , Úlcera Gástrica/patologíaRESUMEN
The diagnosis of granulomatous hepatitis was made on the basis of granulomas observed in the liver biopsies from 64 patients. It is shown that the macrophagal granulomas are, as a rule, localized inside the lobules, do not possess the characteristic features and represent the morphological manifestations of a non-specific reactive hepatitis. At the same time macrophagal granulomas may be a stage in the formation of the epithelioid-cell granulomas. The latter reflect the long persistence of the antigen in the liver macrophages. In certain cases the epithelioid-cell granulomas acquire specific features and these allow one, when analysing the liver biopsies, to confirm or to suggest the etiology of the disease (sarcoidosis, tuberculosis). An essential help in establishing the etiology of granulomatous hepatitis comes from the repeated clinical examination of patients and repeated liver punctures.
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Granuloma/patología , Hepatitis/patología , Hígado/patología , Enfermedad Crónica , Enfermedades del Sistema Digestivo/complicaciones , Granuloma/etiología , Hepatitis/etiología , Humanos , Hígado/ultraestructura , Microscopía Electrónica , Sarcoidosis/complicacionesRESUMEN
The characteristics of all types of chronic gastritis in patients with chronic alcoholism is given. Alterations of the stomach mucous membrane in alcoholism of different duration are described in detail. The intermediate type filaments in the surface epithelium, cells of glands and macrophages are found which is reported to be a morphological manifestation of alcoholism.
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Alcoholismo/patología , Gastritis Atrófica/patología , Gastritis/patología , Adulto , Alcoholismo/complicaciones , Enfermedad Crónica , Mucosa Gástrica/patología , Mucosa Gástrica/ultraestructura , Gastritis Atrófica/etiología , Humanos , Masculino , Microscopía Electrónica , Persona de Mediana EdadRESUMEN
Biopsies of the liver, stomach, pancreas, small salivary glands, lung of patients with chronic alcoholism were studied morphologically including ultrastructural analysis. The formation of fibrillar alcoholic hyalin in hepatocytes is the most characteristic ultrastructural feature of the liver alcoholic damage. Accumulation of intermediate filaments in the epithelial cells of the stomach, pancreas, small salivary glands, stomach macrophages is a characteristic sign of the alcoholic damage to these organs. This disturbance of the structural organization of the cytoskeleton seems to reflect secretory insufficiency of the epithelium and failure of macrophagal function.