On a Nature of Cathodoluminescence Contrast of Fine-Dispersed Structures in the Scanning Electron Microscope

Fine-dispersed structures (FDS) consisting of a large number of microcrystalline or amorphous particles of different sizes and shapes were examined in cathodoluminescence (CL) mode scanning electron microscopy (SEM). Line dimension of each particle (about 10 - 100 μm) was larger than the electron beam diameter as well as electron scattering volume in material under investigation. An analysis of observed images showed the existence of some peculiarities in contrast which have not been observed in the CL-images for solid specimens. The FDS CL-image topographic contrast arises as a result of detection of CL-emission from an aggregate of FDS-elements surrounding an irradiated particle because of the bombardment of the elements by secondary electrons. A model was created for the quantitative description of the secondary electron scattering processes. The model takes into account random distribution of microcrystals in FDS-volume, secondary electron emission, elastic and inelastic electron scattering, elastic and inelastic CL-emission photon scattering, and CL-collector angle aperture. A computer model of the processes described above was made by the Monte-Carlo method to reveal a physical mechanism of FDS CL-image contrast formation. This allowed the calculation of a portion of topographic contrast of FDS CL-images and the dependence of that contrast on depth of a particle position in FDS-volume and on the incident angle of the electron beam on a particle surface. Comparison of the above results with real FDS CL-images shows a good agreement between the theoretical calculations and the experiments

The First Case of <I>Yersinia Pestis</I> Subsp. <I>Pestis</I> Isolation in the Territory of Altai Mountain Natural Plague Focus. Communication 1. Microbiological Characteristics, Molecular-Genetic and Mass-Spectrometric Identification of the Isolate

Performed is a complex microbiological, molecular-genetic and mass-spectrometric identification of Yersinia pestis main ssp. strain, which was isolated for the first time in the history of surveillance over the Altai mountain natural plague focus in June, 2012. Determined is its high universal virulence. Plasmid screening, multi-locus VNTR- and mass-spectrometric analyses have revealed the strain to be more closely related to the plague agent variant, circulating in the territory of the natural focus Khuukh-Serkh-Munkh-Khairkhan, Bayan-Ul’giisk aimak, Mongolia

19F labelled glycosaminoglycan probes for solution NMR and non-linear (CARS) microscopy

Studying polysaccharide-protein interactions under physiological conditions by conventional techniques is challenging. Ideally, macromolecules could be followed by both in vitro spectroscopy experiments as well as in tissues using microscopy, to enable a proper comparison of results over these different scales but, often, this is not feasible. The cell surface and extracellular matrix polysaccharides, glycosaminoglycans (GAGs) lack groups that can be detected selectively in the biological milieu. The introduction of 19F labels into GAG polysaccharides is explored and the interaction of a labelled GAG with the heparin-binding protein, antithrombin, employing 19F NMR spectroscopy is followed. Furthermore, the ability of 19F labelled GAGs to be imaged using CARS microscopy is demonstrated. 19F labelled GAGs enable both 19F NMR protein-GAG binding studies in solution at the molecular level and non-linear microscopy at a microscopic scale to be conducted on the same material, essentially free of background signals

A New Approach for Heparin Standardization: Combination of Scanning UV Spectroscopy, Nuclear Magnetic Resonance and Principal Component Analysis

The year 2007 was marked by widespread adverse clinical responses to heparin use, leading to a global recall of potentially affected heparin batches in 2008. Several analytical methods have since been developed to detect impurities in heparin preparations; however, many are costly and dependent on instrumentation with only limited accessibility. A method based on a simple UV-scanning assay, combined with principal component analysis (PCA), was developed to detect impurities, such as glycosaminoglycans, other complex polysaccharides and aromatic compounds, in heparin preparations. Results were confirmed by NMR spectroscopy. This approach provides an additional, sensitive tool to determine heparin purity and safety, even when NMR spectroscopy failed, requiring only standard laboratory equipment and computing facilities

Analysis and characterization of heparin impurities

This review discusses recent developments in analytical methods available for the sensitive separation, detection and structural characterization of heparin contaminants. The adulteration of raw heparin with oversulfated chondroitin sulfate (OSCS) in 2007–2008 spawned a global crisis resulting in extensive revisions to the pharmacopeia monographs on heparin and prompting the FDA to recommend the development of additional physicochemical methods for the analysis of heparin purity. The analytical chemistry community quickly responded to this challenge, developing a wide variety of innovative approaches, several of which are reported in this special issue. This review provides an overview of methods of heparin isolation and digestion, discusses known heparin contaminants, including OSCS, and summarizes recent publications on heparin impurity analysis using sensors, near-IR, Raman, and NMR spectroscopy, as well as electrophoretic and chromatographic separations

THE STUDY "REGISTER OF PATIENTS AFTER ACUTE STROKE (REGION)." Part 1. Hospital Prospective Register of Patients after Acute Stroke (According to the Results of the Pilot Phase of the Study)

Aim. To assess the main features of the clinical course of acute cerebrovascular accident (ACVA), its short-term and long-term outcomes and quality of pharmacotherapy based on hospital register. Material and methods. The hospital register of acute stroke (AS) was organized in one of the cardiovascular centers in Moscow city. The results of the pilot part of the study are presented (170 patients hospitalized from January 01, 2014 to September 30, 2014 with ACVA living in the service area of one of the closest outpatient clinics). Presence of cardiovascular diseases (CVD) and their risk factors (RF), prehospital therapy, short-term complications including death and pharmacotherapy recommended to survived patients were analyzed using hospital medical records. During ambulatory follow-up (prospective part of the register) the vital status and pharmacotherapy were assessed. Results. The majority of patients with AS had concomitant CVD (on average 2 per patient) and non CVD (on average 1.2 per patient). Data on the risk factors of CVD and their complications were reflected insufficiently in the medical records. Most patients in the prehospital period did not receive adequate treatment for the reduction in the cardiovascular risk. 90 patients survived and were discharged. 1.5-2 years after discharge, information on the vital status was available for 78 (86.7%) patients. 61 of them (78.2%) were alive and 17 (21.8%) died. Conclusion. The pilot part of the REGION register revealed that the majority of patients with AS have concomitant CVD and non-CVD. The overall quality of pharmacotherapy, primary and secondary prevention of ACVA was far from that recommended in clinical guidelines, especially during follow-up in outpatient clinic