Influence of strong π-acceptor ligands on Cr-K-edge X-ray absorption spectral signatures and consequences for the interpretation of surface sites in the Phillips catalyst.

X-ray absorption spectroscopy (XAS) has been central to the study of the Phillips polymerization catalyst (CrO/SiO). As Cr K-edge XAS signatures are sensitive to the oxidation state, geometry and types of ligands on surface (active) sites, the superposition of these effects makes their interpretation challenging. Notably, CO has been particularly used as a reductant to generate low valent Cr sites from CrO/SiO and as a structural IR probe for analysing reduced Cr surface sites.

From a humorous post to a detailed quantum-chemical study: isocyanate synthesis revisited.

Isocyanates play an essential role in modern manufacturing processes, especially in polyurethane production. There are numerous synthesis strategies for isocyanates both under industrial and laboratory conditions, which do not prevent searching for alternative highly efficient synthetic protocols. Here, we report a detailed theoretical investigation of the mechanism of sulfur dioxide-catalyzed rearrangement of phenylnitrile oxide into phenyl isocyanate, which was first reported in 1977.

Improving sensitivity of XANES structural fit to the bridged metal-metal coordination.

Hard X-ray absorption spectroscopy is a valuable in situ probe for non-destructive diagnostics of metal sites. The low-energy interval of a spectrum (XANES) contains information about the metal oxidation state, ligand type, symmetry and distances in the first coordination shell but shows almost no dependency on the bridged metal-metal bond length. The higher-energy interval (EXAFS), on the contrary, is more sensitive to the coordination numbers and can decouple the contribution from distances in different coordination shells.

Deep Reinforcement Learning Environment Approach Based on Nanocatalyst XAS Diagnostics Graphic Formalization.

The most in-demand instrumental methods for new functional nanomaterial diagnostics employ synchrotron radiation, which is used to determine a material's electronic and local atomic structure. The high time and resource costs of researching at international synchrotron radiation centers and the problems involved in developing an optimal strategy and in planning the control of the experiments are acute. One possible approach to solving these problems involves the use of deep reinforcement learning agents.

Quantitative Structural Description of Zeolites by Machine Learning Analysis of Infrared Spectra.

Application of machine learning (ML) algorithms to spectroscopic data has a great potential for obtaining hidden correlations between structural information and spectral features. Here, we apply ML algorithms to theoretically simulated infrared (IR) spectra to establish the structure-spectrum correlations in zeolites. Two hundred thirty different types of zeolite frameworks were considered in the study whose theoretical IR spectra were used as the training ML set.

[Interferon-gamma, idiotypic and anti-idiotypic autoantibodies in pyodermias of various etiology].

Sera of 80 patients with pyodermias of varius etiology were analysed for interferon-gamma (IF-gamma), antiinterferon autoantibodies (IF-a-AB), corresponding antiidiotypic antibodies (IF-AIAB) and the ratio IF-a-AB/IF-AIAB using ELISA assay. There was no correlation between serum IF-gamma and IF-a-AB. Progression of this disease was characterized by an increase of serum IF-a-AB and a decrease of IF-AIAB.

[Physicochemical and immunochemical properties of heavy chains of immunoglobulin G typical of malignant growth].

Molecular weight of heavy chains of immunoglobulin G typical of cancer is studied immunoglobulin and may be responsible for manifestation of certain anomalous acid and peptide composition of this protein heavy chains as compared with immunoglobulin G in blood serum of healthy people. Immunochemical methods helped detecting an antigenic determinant (or determinants) which is arranged in the heavy chains of the studied immunoglobulin and may be responsible for manifestation of certain anomalous properties of cancer-typical immunoglobulin G molecules. A set of bromo-cyanogenic fragments differing from the spectrum of these fragments in the heavy chains of normal immunoglobulin G is formed following a specific chemical effect of bromo-cyanogen on the heavy chains of immunoglobulin G typical of cancer.

[Physicochemical and immunochemical properties of submolecular structures of immunoglobulin G characteristic of cancer].

Studies in physicochemical and immunochemical properties of polipeptide chains fragments of immunoglobulin G malignant growth permitted detecting the location site for a specific determinant which adds a unique feature to the whole molecule of immunoglobulin G. The specific antigenic determinant is defined by a group of amino acids located in the heavy chain site corresponding to Fd-fragment. During papain and trypsin hydrolysis of specific immunoglobulin G obtained from different patients the formed sets of fragments and peptides are different.

[The carbohydrate component of immunoglobulin G peculiar to malignant growth].

The total amount of carbohydrates and some carbohydrate components was studied in total preparations of immunoglobulins of blood serum of healthy people and cancer patients as well as in immunoglobulin G subfraction peculiar to cancer and in the fraction isolated from immunoglobulin G of healthy people blood serum corresponding to the place of column elution. An insignificant increase is established in the content of carbohydrates in the protein peculiar to cancer as compared to their amount in immunoglobulin G of blood serum from healthy people (1.93 and 1.

[Changes in protein spectrum of cattle blood serum with lympholeukosis].

The protein spectrum of blood serum was studied in healthy cows and those suffering from leucosis. The total amount of protein at the early stages of the disease is established to be unchanged. But with lympholeucosis the content of the globulin fraction increases with a simultaneous decrease in the amount of albumins within 20%.

[Electrofocusing of immunoglobulin G that reacts positively in the sedimentation reaction for cancer].

Immunoglobulin G from the serum of patients with myeloma and positively reacting in the sedimentary test for cancer (PPR-STC) was purified by DEAE-Spehadex A-50 and KM-cellulose chromotography and studied by the method of isoelectrofocusing; Application of 1% ampholine within the pH gradient 3.0-10.0 shows the difference between the isoelectric spectra of immunoglobulin G from the donor and from a patient with myeloma.

[Structural peculiarities of protein typical of G-myelomas].

G-myeloma protein is shown to differ by its conformation from the donor immunoglobulin G. It is characterized by a more polar surrounding of the molecule tyrosine and tryptophane residua. Under the effect of urea the changes are less considerable.