Thermal annealing derivatives of technogenic gypsum by electron paramagnetic resonance

© SGEM2016.Previously dehydration products EPR spectra of single crystals of gypsum (“Marino glass”) have been studied in the temperature range from 100 to 425 °C [Crystall. Reports, 2014, Vol. 59, No. 3, pp. 399]. In this work, the subject of study was selected technogenic gypsum and its derivatives dehydration [Procedia Earth and Planet Sci. Vol. 15, 2015, P. 579].Temperature region of formation gypsum, alpha and beta phase states of bassanite and gamma-anhydrite, insoluble anhydrite were determined from the EPR spectra of radical ions and the atomic hydrogen. Obtained results may be used for the control in the technological processes of gypsum materials production, and scientific purposes

Transformation of organic matter of rocks from domanik deposits in hydrothermal and pyrolytic processes

© SGEM 2017. All Rights Reserved. The objects of the study were samples of Domanik rock from Upper Devonian siliceous-carbonate and carbonate sediments of the Romashkinо oil field, which occurs in the central part of the South Tatarian arch in Tatarstan. The composition of organic matter and mineral rock components and bitumoids extracted from them was studied by thermal analysis, X-ray diffraction analysis, SARA analysis and gas chromatography. Significant differences in the mineralogical composition and content of organic matter are found in samples after their hydrothermal treatment at a temperature of 350°C in the steam medium at the carbon dioxide. Based on the example of these rock samples, pyrolytic experiments were conducted to simulate the processes of conversion of kerogen to free micronized oil at temperatures of 350 and 600°C in a hydrogen medium in a flow system. The content of Mn 2+ , SO 3 - , SO 2 - ions in the rock, as well as ions of vanadyl (VO 2+ ) and free radicals (R*) in the pyrolysis products were evaluated using Xband electron paramagnetic resonance (EPR) spectroscopy at frequency of 9.43 GHz. The most significant changes associated with an increase in the concentration of free radicals were observed at 350°C. A new free organic radical C350 was registered In the sample of siliceous-carbonate sediments and a free organic radical C 600 – in carbonate sample, which indicate that the studied rocks did not fully realize their potential in natural hydrocarbon generation processes

Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

Photolysis (λ \u3e 543 nm) of 3-thienyldiazomethane (1), matrix isolated in Ar or N2 at 10 K, yields triplet 3-thienylcarbene (13) and α-thial-methylenecyclopropene (9). Carbene 13 was characterized by IR, UV/vis, and EPR spectroscopy. The conformational isomers of 3-thienylcarbene (s-E and s-Z) exhibit an unusually large difference in zero-field splitting parameters in the triplet EPR spectrum (|D/hc| = 0.508 cm–1, |E/hc| = 0.0554 cm–1; |D/hc| = 0.579 cm–1, |E/hc| = 0.0315 cm–1). Natural Bond Orbital (NBO) calculations reveal substantially differing spin densities in the 3-thienyl ring at the positions adjacent to the carbene center, which is one factor contributing to the large difference in D values. NBO calculations also reveal a stabilizing interaction between the sp orbital of the carbene carbon in the s-Z rotamer of 13 and the antibonding σ orbital between sulfur and the neighboring carbon—an interaction that is not observed in the s-E rotamer of 13. In contrast to the EPR spectra, the electronic absorption spectra of the rotamers of triplet 3-thienylcarbene (13) are indistinguishable under our experimental conditions. The carbene exhibits a weak electronic absorption in the visible spectrum (λmax = 467 nm) that is characteristic of triplet arylcarbenes. Although studies of 2-thienyldiazomethane (2), 3-furyldiazomethane (3), or 2-furyldiazomethane (4) provided further insight into the photochemical interconversions among C5H4S or C5H4O isomers, these studies did not lead to the spectroscopic detection of the corresponding triplet carbenes (2-thienylcarbene (11), 3-furylcarbene (23), or 2-furylcarbene (22), respectively)

Some clinical and diagnostic features of patients with new-onset epilepsy in the presence of chronic cerebrovascular disease

Objective: to investigate the specific features of epilepsy that manifests itself in the presence of chronic cerebrovascular disease.Patients and methods. A total of 304 patients (a study group of 174 patients with new-onset seizures developing in the presence of cerebrovascular disease and a control group of 130 patients with cerebrovascular disease and no seizures) were examined. They underwent clinical neurological examination, electroencephalography (EEG), ultrasonic duplex scanning of extra- and intracranial arteries with functional tests, and visualization of brain structures.Results. Focal seizures were prevalent in the patients with cerebrovascular disease and epilepsy. It was found that there was a preponderance of left-sided localization of EEG foci of abnormal activity and a tendency to more commonly detect subcritical and critical stenoses in the left carotid bed in the patients with epileptic seizures. Diminished perfusion reserves in the posterior circulation system were more frequently observed in the patients with seizures in the presence of cardiovascular diseases. Moreover, the patients with seizures displayed a more profound degree of brain ischemia with the frequent cortical and subcortical localization of dyscirculatory foci. Thus, a study of perfusion reserves, localization of vascular foci, and degree of occlusive changes in the wall of brachiocephalic vessels allows identification of risk factors for epilepsy in the patients with cerebrovascular disease and promotes the prediction of the course of the disease

Contraction of blood clots is impaired in acute ischemic stroke

© 2016 American Heart Association, Inc.Objective - Obstructive thrombi or thrombotic emboli are the pathogenic basis of ischemic stroke. In vitro blood clots and in vivo thrombi can undergo platelet-driven contraction (retraction), resulting in volume shrinkage. Clot contraction can potentially reduce vessel occlusion and improve blood flow past emboli or thrombi. The aim of this work was to examine a potential pathogenic role of clot contraction in ischemic stroke. Approach and Results - We used a novel automated method that enabled us to quantify time of initiation and extent and rate of clot contraction in vitro. The main finding is that clot contraction from the blood of stroke patients was reduced compared with healthy subjects. Reduced clot contraction correlated with a lower platelet count and their dysfunction, higher levels of fibrinogen and hematocrit, leukocytosis, and other changes in blood composition that may affect platelet function and properties of blood clots. Platelets from stroke patents were spontaneously activated and displayed reduced responsiveness to additional stimulation. Clinical correlations with respect to severity and stroke pathogenesis suggest that the impaired clot contraction has the potential to be a pathogenic factor in ischemic stroke. Conclusions - The changeable ability of clots and thrombi to shrink in volume may be a novel unappreciated mechanism that aggravates or alleviates the course and outcomes of ischemic stroke. The clinical importance of clot or thrombus transformations in vivo and the diagnostic and prognostic value of this blood test for clot contraction need further exploration

Contraction of blood clots is impaired in acute ischemic stroke

© 2016 American Heart Association, Inc.Objective - Obstructive thrombi or thrombotic emboli are the pathogenic basis of ischemic stroke. In vitro blood clots and in vivo thrombi can undergo platelet-driven contraction (retraction), resulting in volume shrinkage. Clot contraction can potentially reduce vessel occlusion and improve blood flow past emboli or thrombi. The aim of this work was to examine a potential pathogenic role of clot contraction in ischemic stroke. Approach and Results - We used a novel automated method that enabled us to quantify time of initiation and extent and rate of clot contraction in vitro. The main finding is that clot contraction from the blood of stroke patients was reduced compared with healthy subjects. Reduced clot contraction correlated with a lower platelet count and their dysfunction, higher levels of fibrinogen and hematocrit, leukocytosis, and other changes in blood composition that may affect platelet function and properties of blood clots. Platelets from stroke patents were spontaneously activated and displayed reduced responsiveness to additional stimulation. Clinical correlations with respect to severity and stroke pathogenesis suggest that the impaired clot contraction has the potential to be a pathogenic factor in ischemic stroke. Conclusions - The changeable ability of clots and thrombi to shrink in volume may be a novel unappreciated mechanism that aggravates or alleviates the course and outcomes of ischemic stroke. The clinical importance of clot or thrombus transformations in vivo and the diagnostic and prognostic value of this blood test for clot contraction need further exploration

Применение ботулинотерапии при постинсультной спастичности нижней конечности (клинические наблюдения)

The paper deals with the topical problem – the medical rehabilitation of patients with poststroke spasticity. It describes clinical cases of patients with poststroke spasticity of the upper and lower extremities who have received combined therapy using botulinum toxin type A (Botox) injections.Статья посвящена актуальной проблеме – медицинской реабилитации пациентов с постинсультной спастичностью. Приводятся клинические наблюдения пациентов с постинсультной спастичностью верхней и нижней конечности, получивших комбинированную терапию с применением инъекций ботулотоксина типа А (Ботокс)

Contraction (Retraction) of blood clots in patients with ischemic stroke

© 2016, Media Sphera. All rights reserved.Objective: To study a possible pathogenetic role of the blood clot contraction and its disturbances in the acute stage of ischemic stroke (IS). Material and methods: Using a new instrumental technique to study the dynamics of clot contraction in vitro, the authors have determined quantitative parameters of clot contraction (the extent and rate of contraction, duration of the lag-period) in the blood of 85 patients with acute IS. Results and Conclusion: The contractile activity of blood clots was substantially reduced compared to the blood of healthy subjects. Correlations between hemostatic and contractile parameters suggest that the reduced clot contraction in stroke is due to the lower platelet count and impaired platelet functionality, higher levels of fibrinogen and antithrombin III as well as higher hematocrit and hemoglobin contents, leukocytosis, and changes in the biochemical blood composition. The results show that the reduced ability of clots may be a novel pathogenic mechanism that aggravates the course and outcomes of IS

Theory of a Higher Order Phase Transition: Superconducting Transition in BKBO

We describe here the properties expected of a higher (with emphasis on the order fourth) order phase transition. The order is identified in the sense first noted by Ehrenfest, namely in terms of the temperature dependence of the ordered state free energy near the phase boundary. We have derived an equation for the phase boundary in terms of the discontinuities in thermodynamic observables, developed a Ginzburg-Landau free energy and studied the thermodynamic and magnetic properties. We also discuss the current status of experiments on $Ba_{0.6}K_{0.4}BiO_3$ and other $BiO_3$ based superconductors, the expectations for parameters and examine alternative explanations of the experimental results.Comment: 18 pages, no figure

The unusual cause of stroke: Cerebral dural arteriovenous fistula

Based on the data available in the literature and their own experience, the authors give current views on the etiology, pathogenesis, classification, clinical presentations, and treatments of cerebral dural arteriovenous fistula (DAVF), one of the unusual causes of stroke. The paper describes a young male patient with the lobar localization of the focus, a concurrence of ischemic stroke and hemorrhagic stroke. It is stated that the early emergence and persistence of a considerable focus should alert the physician to the possibility of DAVF or another venous anomaly. An emphasis is laid on the leading role of multimodal imaging protocols in the early diagnosis of the disease. Selective cerebral angiography of the internal and external carotid and vertebral arteries is today the gold standard for the diagnosis and classification of DAVF