Raman scattering spectroscopy of MBE grown thin film topological insulator Bi2-xSbxTe3-ySey.

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.

Super-resolution THz endoscope based on a hollow-core sapphire waveguide and a solid immersion lens.

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.

Prospects for the use of graphene-based biological sensors in the early diagnosis of Alzheimer's disease (review of literature).

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.

Low-temperature quantum magnetotransport of graphene on SiC (0 0 0 1) in pulsed magnetic fields up to 30 T.

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.

Optical thermometry based on level anticrossing in silicon carbide.

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.

[Idiopathic jaundice in pregnancy]. / Idiopaticheskaia zheltukha beremennykh

PIP: In cases of intensive jaundice accompanying pregnancy, the activity of hepatic genesis is to be strongly considered. As an example, the case of 22-year-old woman with a jaundice of an uncertain genesis, in the 18th week of pregnancy, is examined. After 2 more weeks of examination, a diagnosis of severe viral hepatitis was made. The pregnancy was terminated in the 20th week. After the abortion, the condition did not improve. Further examination showed confusing results, which were finally diagnosed as choleostasic hepatitis. Retrospective examination of diagnostic results lead to the conclusion that the actual problem was idiopathic jaundice.^ieng

[Morphology and pathogenesis of visceral manifestations of chronic alcoholism]. / Morfologiia i patogenez vistseral'nykh proiavlenii khronicheskogo alkogolizma.

Chronic alcoholism is accompanied by systemic involvement of the internal organs. Clinico-morphological forms of chronic alcoholism are distinguished on the basis of the prevailing organ pathology, Morphological data are presented, and pathogenesis of the lesions of the liver, heart, pancreas, and kidneys in patients with chronic alcoholism is analysed. The hepatic form may present alcoholic dystrophy, hepatitis or cirrhosis which are stages of progressing hepatopathy. The toxic and metabolic effect of ethanol is important in the pathogenesis of liver lesion. The cardiac form is characterized by the development of alcoholic myocardiodystrophy. In addition to the toxic influence of ethanol, hormonal and electrolyte changes and microcirculatory disorders play a role in its pathogenesis. Chronic calcifying pancreatitis in chronic alcoholism is associated with the effect of ethanol on the mediatory system. The renal form any present necronephrosis, hepatorenal syndrome, glomerulonephritis or pyelonephritis. Their pathogenesis is determined by toxicity of ethanol, circulation of immune complexes in the blood, or immunosuppression.

[Diagnosis of alcoholic liver cirrhosis during autopsy]. / Diagnostika alkogol'nogo tsirroza pecheni u sektsionnogo stola.

Approaches for the diagnosis of alcoholic cirrhosis of the liver at the dissecting table are given on the basis of the analysis of autopsy materials and liver biopsies. The etiological verification of cirrhosis is based on the peculiar morphological lesions of the liver and other organs. The liver is enlarged, its surface micronodal; histologically, an attack of acute alcoholic hepatitis is found not infrequently: necroses of hepatocytes, predominantly neutrophilic infiltration of the stroma and necrotic zones, alcoholic hyalin. Due to autolysis, alcoholic hyalin in the autopsy material changes somehow and is hardly detectable. A combination of alcoholic cirrhosis of the liver with alcoholic cardiopathy and/or chronic calcifying pancreatitis is typical.

[Diffuse pulmonary leiomyomatosis]. / Diffuznyi leiomiomatoz legkikh.

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.

[Clinical morphology of alcoholism]. / Klinicheskaia morfologiia alkogolizma.

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.

[Morphology and various problems of the pathogenesis of alcoholic microangiopathy]. / Morfologiia i nekotorye voprosy patogeneza alkogol'noi mikroangiopatii.

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.

[Alcoholic lesions of the liver (morphology and several questions concerning pathogenesis)]. / Alkogol'nye porazheniia pecheni (morfologiia i nekotorye voprosy patogeneza)

On the basis of morphological studies of 130 puncture material of the liver in 100 patients with chronic alcoholism the three morphological forms of its lesion were identified: dystrophic changes in hepacytes; alcoholic hepatitis (acute and chronic); cirrhosis of the liver. It is suggested that the morphological forms mentioned above represent the stages of one process--developing alcoholic hepatopathy. Progressing of the process in the liver in chronic alcoholism is connected with necroses of hepacytes as a result of toxic effect of alcohol with a subsequent reaction of the cells of the portal stroma and sinusoids. Gravity of lesions of the liver depends largerly on individual sensitivity to alcohol, one of the main factor of which may be the capacity of the liver to reproduce ADG.

[The morphology and morphogenesis of alcoholic cirrhosis of the liver]. / Morfologiia i morfogenez alkogol'nogo tsirroza pecheni

A total of 42 biopsy specimens of the liver (blind and spot) in 32 patients with alcoholic cirrhosis of the liver were investigated. Morphological, portal, postnecrotic, and mixed types of cirrhosis were established. The portal type of cirrhosis is most common. On the basis of repeated analyses of biopsy materials of the liver it may be assumed that the development of cirrhosis of the liver of alcoholic etiology is connected with multiple attacks of acute alcoholic hepatitis. Abstention from alcohol consumption resulted in stifestations of exacerbation of cirrhosis. On the other hand, continuation of alcohol consumption contributed to progressing of cirrhosis, which following several attacks of alcoholic hepatitis, may change its morphological type: portal cirrhosis "transforms" into the postnecrotic or mixed type. The data obtained clarified the role of ethanol in progressing alcoholic cirrhosis of the liver, which according to the initial mecranisms of its development in postnecrotic, since every attack of acute alcoholic hepatitis is accompanied by coagulative (fields of alcoholic hyaline, or Mallory's bodies), or by colliquative (balloon dystrophy) necrosis of hepacytes.

[Diagnosis of viral liver cirrhosis in the practice of the pathologist]. / Diagnostika virusnogo tsirroza pecheni v praktike patologoanatoma.

An autopsy observation of viral cirrhosis of the liver is presented. Along with the clinical data, morphological diagnosis of viral cirrhosis of the liver one should take into account not only the nature of cirrhosis (macronodular surface, multilobular structure of regenerative nodes, wide fibrous septae and lymphohistiocyte infiltration, Councilman bodies, "frosted vitreous" hepatocytes, mature lipofuscin in hepatocytes) but also the possibility of detecting HBsAg in paraffin sections of the liver stained with orseine and aldehydethionine.

[Hepatitis and cirrhosis of the liver (classification, morphology and morphological differential diagnosis]. / Gepatiti, tsirroz pecheni (klassifikatsiia, morfologiia, morfologicheskaia differentsial'naia diagnostika).

The current classification of hepatitis and hepatocirrhosis is evaluated on the basis of the literature analysis and the study of the author's own material. Morphological criteria for differential diagnosis of liver diseases of viral and alcohol etiology are proposed. A clinical pathologist examining a liver biopsy may confirm or establish the etiology of the disease, determine the degree of activity and compensation of the process. An analysis of these criteria helps a clinician to choose the method of treatment and to determine the prognosis of the disease.

[Alcoholic hyalin and interstitial filaments as markers of alcoholic damage of internal organs]. / Alkogol'nyi gialin i promezhutochnye filamenty kak markery alkogol'nogo porazheniia vnutrennikh organov.

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.

[Granulomatous hepatitis]. / Granulematoznyi gepatit.

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.

[Campylobacter pylori in patients with liver cirrhosis of different etiologies]. / Campylobacter pylori u bol'nykh tsirrozom pecheni razlichnoi étiologii.

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.

[Morphological variants of alcoholic hyalin and possible ways of its evolution]. / Morfologicheskie varianty alkogol'nogo gialina i vozmozhnye puti ego evoliutsii.

Possible ways of alcohol hyalin evolution were studied by repeated electron microscopic examinations of the livers of 2 patients with acute alcoholic hepatitis Four types of ultrastructure of alcoholic hyalin were found: parallely oriented fibrillae, randomly oriented fibrillae, fine granular and large granular (spotlike) substance. Examinations of the material from repeated biopsies showed fibrillar hyalin to be "young" and to turn into "old" hyalin of granular structure. The evolution of alcoholic hyalin from fibrillar to granular is accompanied by hepatocyte necrosis and leukotaxic effect.

[Experience in conducting a test exam in pathological anatomy]. / Opyt provedeniia testovogo ékzamena po patologicheskoi anatomii.

Taking into consideration the experience in examinations at medical schools of various countries and personal experience in conducting examinations by the test method, the authors believe that the test method should be used at examinations in order to assess the knowledge of the students objectively, particularly, when the number of students to be examined is large. This method is sufficiently effective, time saving, permits one to correlate the results of teaching with the tasks set, to detect defects in studying some parts of the course and to correct the process of teaching. It should be used only partially, however, to examine the knowledge of the theoretical part of the course, whereas the practical part should be presented at oral exams allowing personal contacts of the teachers and the students.