56 research outputs found

    Basics of Building and Analyzing Adaptively Targeted Forecast Models for Supply Chain Management

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    Abstract— Forecasting is an under estimated field of research in supply chain management. To describe the methodology for building adaptively targeted forecast models based on the recursive least squares method and to show the possibility of using these models in economic analysis. Two cases were studied, which include targeting by a single given target value and by a target trajectory described by several consecutive values. It was shown that for the autoregressive model in the case of setting several target values, the multistep procedure of the recursive least squares method is not applicable. It was also possible to clarify the necessity of introducing changes into the adaptive regression analysis scheme for the case when the adaptively targeted model is built on the basis of the autoregressive one. Procedures for building adaptively targeted models for supply chain management of setting target conditions have been proposed. The adaptive regression analysis technique has been modified for the case of an adaptively targeted autoregressive model

    Basics of building and analyzing adaptively targeted forecast models for supply chain management

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    Forecasting is an under estimated field of research in supply chain management. To describe the methodology for building adaptively targeted forecast models based on the recursive least squares method and to show the possibility of using these models in economic analysis. Two cases were studied, which include targeting by a single given target value and by a target trajectory described by several consecutive value

    RELATIONSHIP BETWEEN SINGLE NUCLEOTIDE POLYMORPHISMS IN CYTOKINE GENES AND CLINICAL LABORATORY PARAMETERS IN PATIENTS WITH MULTIPLE MYELOMA

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    Multiple myeloma is the most common form of paraproteinemic hemoblastosis, which is characterized by variability of clinical manifestations, forms, and variants. Limited efficiency of antitumor immune protection in the patient plays an important role in progression of this disease. Survival of myeloma cells is promoted by some growth factors, including a number of interleukins. Cytokines and chemokines are secreted in response to intercellular interactions and stimulate tumor growth, inhibition of osteoblasts and increase of the osteoclastic activity. Cytokine genes show a significant allelic polymorphism. A single gene may exhibit numerous polymorphic sites located in exons, introns and promoter regulatory areas. Single nucleotide substitutions in the promoter region of cytokine genes are known to have a huge impact upon secretion and biological activity of these factors. Therefore, a study of allelic gene variants determining the levels of cytokine production will allow of establishing new immunogenetic factors associated with a high risk of disease development, including multiple myeloma. We have studied single nucleotide polymorphism in cytokine genes (IL-1α -889 TT, IL-1β +3962 TT, IL-6 -174 GG, and IL-6 nt565 GG), and clinical laboratory parameters (serum levels of albumin, β2-microglobulin, and hemoglobin) determining severity grade of multiple myeloma in 80 patients living in the North-Western region of Russia. It was found that the presence of certain cytokine gene variants, i.e., IL-1α -889 TT, IL-1β +3962 TT, IL-6 -174 GG, IL-6 nt565 GG or IL-1α -889 TT, IL- 1β +3962 TT or IL-6 -174 GG, IL-6 nt565 GG was associated with low albumin levels (< 3.5 g/DL), and high levels of β2-microglobulin (> 5.5 mg/l). A combination of all the four negative variants in homozygous state (IL- 1α TT -889, IL-1β +3962 TT, IL-6 -174 GG and IL-6 nt565 GG) increases the chance of six-fold reduction of albumin levels (p < 0.05); combinations of homozygous IL-1α TT -889, IL-1β +3962 TT, IL-6-174 GG. and IL-6 nt565 GG are associated with increased chance of high-level β2-microglobulin (> 5.5 mg/l) by more than two times. This data allow to consider IL-1α -889 TT, IL-1β +3962 TT, IL-6 -174 GG, and IL-6 nt565 GG genotypes additional negative immunogenetic factors in the prognosis of multiple myeloma

    Evolution of oxygen-ion and proton conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), located near pyrochlore fluorite phase boundary

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    Sm2-xCaxZr2O7-x/2 (x = 0, 0.05, 0.1) and Gd2-xCaxZr2O7-x/2 (x = 0.05, 0.1) mixed oxides in a pyrochlore-fluorite morphotropic phase region were prepared via the mechanical activation of oxide mixtures, followed by annealing at 1600 ?C. The structure of the solid solutions was studied by X-ray diffraction and refined by the Rietveld method, water content was determined by thermogravimetry (TG), their bulk and grain-boundary conductivity was determined by impedance spectroscopy in dry and wet air (100-900 ?C), and their total conductivity was measured as a function of oxygen partial pressure in the temperature range: 700-950 ?C. The Sm2-xCaxZr2O7-x/2 (x = 0.05, 0.1) pyrochlore solid solutions, lying near the morphotropic phase boundary, have proton conductivity contribution both in the grain bulk and on grain boundaries below 600 ?C, and pure oxygen-ion conductivity above 700 ?C. The 500 ?C proton conductivity contribution of Sm2-xCaxZr2O7-x/2 (x = 0.05, 0.1) is ~ 1 ? 10-4 S/cm. The fluorite-like Gd2-xCaxZr2O7-x/2 (x = 0.1) solid solution has oxygen-ion bulk conductivity in entire temperature range studied, whereas proton transport contributes to its grain-boundary conductivity below 700 ?C. As a result, of the morphotropic phase transition from pyrochlore Sm2-xCaxZr2O7-x/2 (x = 0.05, 0.1) to fluorite-like Gd2-xCaxZr2O7-x/2 (x = 0.05, 0.1), the bulk proton conductivity disappears and oxygen-ion conductivity decreases. The loss of bulk proton conductivity of Gd2-xCaxZr2O7-x/2 (x = 0.05, 0.1) can be associated with the fluorite structure formation. It is important to note that the degree of Ca substitution in such solid solutions (Ln2-xCax)Zr2O7-? (Ln = Sm, Gd) is low, x < 0.1. In both series, grain-boundary conductivity usually exceeds bulk conductivity. The high grain-boundary proton conductivity of Ln2-xCaxZr2O7-x/2 (Ln = Sm, Gd; x = 0.1) is attributable to the formation of an intergranular CaZrO3-based cubic perovskite phase doped with Sm or Gd in Zr sublattice. ? 2019 by the authors.371C-9F16-EBDE | Eduarda GomesN/

    Fused eco29kIR- and M genes coding for a fully functional hybrid polypeptide as a model of molecular evolution of restriction-modification systems

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    <p>Abstract</p> <p>Background</p> <p>The discovery of restriction endonucleases and modification DNA methyltransferases, key instruments of genetic engineering, opened a new era of molecular biology through development of the recombinant DNA technology. Today, the number of potential proteins assigned to type II restriction enzymes alone is beyond 6000, which probably reflects the high diversity of evolutionary pathways. Here we present experimental evidence that a new type IIC restriction and modification enzymes carrying both activities in a single polypeptide could result from fusion of the appropriate genes from preexisting bipartite restriction-modification systems.</p> <p>Results</p> <p>Fusion of <it>eco29kIR </it>and <it>M </it>ORFs gave a novel gene encoding for a fully functional hybrid polypeptide that carried both restriction endonuclease and DNA methyltransferase activities. It has been placed into a subclass of type II restriction and modification enzymes - type IIC. Its MTase activity, 80% that of the M.Eco29kI enzyme, remained almost unchanged, while its REase activity decreased by three times, concurrently with changed reaction optima, which presumably can be caused by increased steric hindrance in interaction with the substrate. <it>In vitro </it>the enzyme preferentially cuts DNA, with only a low level of DNA modification detected. <it>In vivo </it>new RMS can provide a 10<sup>2</sup>-fold less protection of host cells against phage invasion.</p> <p>Conclusions</p> <p>We propose a molecular mechanism of appearing of type IIC restriction-modification and M.SsoII-related enzymes, as well as other multifunctional proteins. As shown, gene fusion could play an important role in evolution of restriction-modification systems and be responsible for the enzyme subclass interconversion. Based on the proposed approach, hundreds of new type IIC enzymes can be generated using head-to-tail oriented type I, II, and III restriction and modification genes. These bifunctional polypeptides can serve a basis for enzymes with altered recognition specificities. Lastly, this study demonstrates that protein fusion may change biochemical properties of the involved enzymes, thus giving a starting point for their further evolutionary divergence.</p

    Conformational Basis for Asymmetric Seeding Barrier in Filaments of Three- and Four-Repeat Tau

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    *S Supporting Information ABSTRACT: Tau pathology in Alzheimer’s disease is intimately linked to the deposition of proteinacious filaments, which akin to infectious prions, have been proposed to spread via seeded conversion. Here we use double electron−electron resonance (DEER) spectroscopy in combination with extensive computational analysis to show that filaments of three- (3R) and four-repeat (4R) tau are conformationally distinct. Distance measurements between spin labels in the third repeat, reveal tau amyloid filaments as ensembles of known β-strand−turn−β-strand U-turn motifs. Whereas filaments seeded with 3R tau are structurally homogeneous, filaments seeded with 4R tau are heterogeneous, composed of at least three distinct conformers. These findings establish a molecular basis for the seeding barrier between different tau isoforms and offer a new powerful approach for investigating the composition and dynamics of amyloid fibril ensembles

    Single-sided hydrogen bonding to the quinone cofactor in photosystem I probed by selective 13C-labelled naphthoquinones and transient EPR

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    Hydrogen bonding between teh protein and one or both of the two 1,4-quinone carbonyl groups of a benzo-or naphtho-quinone constitutes a significant protein-cofactor interaction in photosynthetic reaction centers. The redistribution of charge and spin density due to a particular H-bonding scheme leaves the largest hyperfine couplings (hfc) at the highest density positions, i.e., the nuclei of the carbonyl groups directly involved in H-bonding. The spin density changes at the ring carbon positions are accessed exeripmentlaly via electron paramagnetic resonance-determined hfc tensor elements of selective13C isotope labels in one of the two carbonyl groups. Complete hfc tensor data are presented for each of the13C positions in the functional charge-separated state in reaction centers of phytosystem I (PS I) isolated from cyanobacteria. A highly asymmetric H-bonding scheme for the A1 quinone binding site due to a single dominant H-bond to one carbonyl group is confirmed. A comparison to other wel-studied quinone binding sites of other protien-cofactor systems with more complex H-bonding schemes reveals the uniqueness of the PS I site. The single-sided A1 quinone site provides an ideal test case for the various sets of density functional theory (DFT) calculations that are currently available. While the overall agreement between experimental and calculated data is quite satisfactory, a significant discrepancy is found for the high-spin-density13C position associated with the H-bonded carbonyl. The dominant hfc component (and spin density) is underestimated in the DFT calculations, not only for the high-asymmetry case in PS I, but also for other quinone binding sites with less asymmetry that result from more complex H-bonding schemes. The cosnequences and potential relevance of this finding for biological function are discussed
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