The strong coupling effect and auxiliary fields in the DGP-model

The DGP-model with additional terms in the action is considered. These terms have a special form and include auxiliary scalar fields without kinetic terms, which are non-minimally coupled to gravity. The use of these fields allows one to exclude the mode, which corresponds to the strong coupling effect, from the theory. Effective four-dimensional theory on the brane appears to be the same, as in the original DGP-model.Comment: 9 pages, LaTe

A microrheological study of sickle hemoglobin polymerization

Sickle hemoglobin (HbS) is a genetic alteration of normal hemoglobin A (HbA). In HbS, a surface amino acid (b6) is transformed from charged (Glu) to hydrophobic (Val). This leads to the formation of multi‐stranded polymers, which in turn are found in interconnected arrays called domains. The polymer stiffness and interconnections cause the cells containing suchhemoglobin to become rigid, thereby blocking the microcirculation. Although the central problem of sickle cell disease is rheological, no experiments are known that can relate rheologyat the cellular scale to the polymer formation that is its cause. A new technique has been developed to measure Rheology at microscopic scales that allow us to control polymerformation and characterize the formed domains at the same time. The created experimental apparatus and the established measurement techniques will be presented, results and theirimplication on our understanding of sickle hemoglobin rheology will be discussed. The unusual universality of sickle hemoglobin rigidity dependence on the amount of the formed polymer will be presented and discussed.Ph.D., Physics -- Drexel University, 200

Measurement of feeder performance during coal discharge from an underroof seam using machine vision

The technology for extracting and discharging coal from an underroof seam uses the so-called gravitational extraction method in which coal is extracted and discharged from under the roof by gravity. Here, coal can be discharged onto the main conveyor (face conveyor, located in the supported area), central conveyor (rear conveyor in Western literature), and tail conveyor (discharge conveyor, located in the unsupported area). The most common facilities used currently are longwall sets of equipment providing discharge onto tail conveyors. The purpose of this study is to measure the performance of a motorised plate feeder supplying coal from the outlet port of a roof support to a conveyor during the extraction of thick seams with discharge onto the face conveyor. To achieve the goal, it is proposed to measure the coal volume using machine vision. Methods for calculating a unit volume in a measuring section using a three-dimensional model were investigated. Laboratory studies were carried out to estimate the relative errors of the methods. The research allowed properly defining: a method for collecting data to calculate the unit volume of coal; a method for calculating the unit volume in the measuring section; a method for calculating the feeder performance using machine vision, and approaches for physically simplifying the video scene examined by machine vision. A relative error of less than 10 % with the existing measurement accuracy for constructing a coal layer surface height map indicates the sufficiency of the proposed calculation method for engineering use. The developed mathematical apparatus for calculating the unit volume of coal at the measuring section and measuring the feeder performance allows creating algorithmic software using the elementary mathematical functions of addition, subtraction, multiplication, and division. This aspect is important because it lower sights for the software development environment, and therefore expands the range of hardware suitable for calculating the feeder performance

Phylogenetic analysis of variants of the Puumala virus (Hantaviridae: <i>Orthohantavirus</i>) circulating in the Saratov region

The objective is to determine the complete nucleotide sequence and conduct a phylogenetic analysis of genome variants of the Puumala virus isolated in the Saratov region. Materials and methods. The samples for the study were field material collected in the Gagarinsky (formerly Saratovsky), Engelssky, Novoburassky and Khvalynsky districts of the Saratov region in the period from 2019 to 2022. To specifically enrich the Puumala virus genome in the samples, were used PCR and developed a specific primer panel. Next, the resulting PCR products were sequenced and the fragments were assembled into one sequence for each segment of the virus genome. To construct phylogenetic trees, the maximum parsimony algorithm was used. Results. Genetic variants of the Puumala virus isolated in the Saratov region have a high degree of genome similarity to each other, which indicates their unity of origin. According to phylogenetic analysis, they all form a separate branch in the cluster formed by hantaviruses from other subjects of the Volga Federal District. The virus variants from the Republics of Udmurtia and Tatarstan, as well as from the Samara and Ulyanovsk regions, are closest to the samples from the Saratov region. Conclusion. The data obtained show the presence of a pronounced territorial confinement of strains to certain regions or areas that are the natural biotopes of their carriers. This makes it possible to fairly accurately determine the territory of possible infection of patients and/or the circulation of carriers of these virus variants based on the sequence of individual segments of their genome

Elevated AKR1C3 expression promotes prostate cancer cell survival and prostate cell-mediated endothelial cell tube formation: implications for prostate cancer progressioan

<p>Abstract</p> <p>Background</p> <p>Aldo-keto reductase (AKR) 1C family member 3 (AKR1C3), one of four identified human AKR1C enzymes, catalyzes steroid, prostaglandin, and xenobiotic metabolism. In the prostate, AKR1C3 is up-regulated in localized and advanced prostate adenocarcinoma, and is associated with prostate cancer (PCa) aggressiveness. Here we propose a novel pathological function of AKR1C3 in tumor angiogenesis and its potential role in promoting PCa progression.</p> <p>Methods</p> <p>To recapitulate elevated AKR1C3 expression in cancerous prostate, the human PCa PC-3 cell line was stably transfected with an AKR1C3 expression construct to establish PC3-AKR1C3 transfectants. Microarray and bioinformatics analysis were performed to identify AKR1C3-mediated pathways of activation and their potential biological consequences in PC-3 cells. Western blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and an <it>in vitro </it>Matrigel angiogenesis assays were applied to validate the pro-angiogenic activity of PC3-AKR1C3 transfectants identified by bioinformatics analysis.</p> <p>Results</p> <p>Microarray and bioinformatics analysis suggested that overexpression of AKR1C3 in PC-3 cells modulates estrogen and androgen metabolism, activates insulin-like growth factor (IGF)-1 and Akt signaling pathways, as well as promotes tumor angiogenesis and aggressiveness. Levels of IGF-1 receptor (IGF-1R) and Akt activation as well as vascular endothelial growth factor (VEGF) expression and secretion were significantly elevated in PC3-AKR1C3 transfectants in comparison to PC3-mock transfectants. PC3-AKR1C3 transfectants also promoted endothelial cell (EC) tube formation on Matrigel as compared to the AKR1C3-negative parental PC-3 cells and PC3-mock transfectants. Pre-treatment of PC3-AKR1C3 transfectants with a selective IGF-1R kinase inhibitor (AG1024) or a non-selective phosphoinositide 3-kinases (PI3K) inhibitor (LY294002) abolished ability of the cells to promote EC tube formation.</p> <p>Conclusions</p> <p>Bioinformatics analysis followed by functional genomics demonstrated that AKR1C3 overexpression promotes angiogenesis and aggressiveness of PC-3 cells. These results also suggest that AKR1C3-mediated tumor angiogenesis is regulated by estrogen and androgen metabolism with subsequent IGF-1R and Akt activation followed by VEGF expression in PCa cells.</p

The microrheology of sickle hemoglobin gels

Sickle cell disease is a rheological disease, yet no quantitative rheological data exist on microscopic samples at physiological concentrations. We have developed a novel method for measuring the microrheology of sickle hemoglobin gels, based on magnetically driven compression of 5- to 8-mu m-thick emulsions containing hemoglobin droplets similar to 80 mu m in diameter. Using our method, by observing the expansion of the droplet area as the emulsion is compressed, we were able to resolve changes in thickness of a few nanometers with temporal resolution of milliseconds. Gels were formed at various initial concentrations and temperatures and with different internal domain structure. All behaved as Hookean springs with Young's modulus from 300 to 1500 kPa for gels with polymerized hemoglobin concentration from 6 g/dl to 12 g/dl. For uniform, multidomain gels, Young's modulus mainly depended on the terminal concentration of the gel rather than the conditions of formation. A simple model reproduced the quadratic dependence of the Young's modulus on the concentration of polymerized hemoglobin. Partially desaturated samples also displayed quadratic concentration dependence but with a smaller proportionality coefficient, as did samples that were desaturated in steps; such samples were significantly less rigid than gels formed all at once. The magnitude of the Young's modulus provides quantitative support for the dominant models of sickle pathophysiology

Effect of Mono- and Multichlorinated Organic Compounds—Chlorocyclohexane and Hexachloro-<i>p</i>-xylene—On the Catalytic Properties of Titanium–Magnesium Catalysts in the Homo- and Copolymerization of Ethylene with 1-Hexene

Ethylene polymerization and ethylene/1-hexene copolymerization over the titanium–magnesium catalytic system in the presence of chlorocyclohexane (CHC) and hexachloro-p-xylene (HCPX) has been studied. Modification of TMC with chlorocyclohexane and hexachloro-p-xylene increased catalyst activity severalfold for both ethylene polymerization and ethylene/1-hexene copolymerization. The key kinetic regularities of ethylene homopolymerization and ethylene/1-hexene copolymerization in the presence of CHC and HCPX were determined, and the copolymerization constants were measured. Molecular characteristics and the copolymer composition were determined for the synthesized samples of ethylene homopolymers and ethylene/hexene copolymers. Modification of the titanium–magnesium catalyst with chlorinated organic compounds reduced 1-hexene content in the copolymer; polymerization was sensitive to 1-hexene as a regulator of polymer molecular weight. The potential mode of action of chlorinated organic modifiers on catalytic properties of titanium–magnesium catalyst is discussed

Au–Ru Composite for Enzyme-Free Epinephrine Sensing

We report the synthesis and investigation of Au–Ru composite with highly developed specific surface area exhibiting excellent electrocatalytic performance suitable for detection of such hydrophobic metabolites as epinephrine in the physiological environment. This electrode material was fabricated using two-stage laser-assisted metal deposition technique. The morphological and structural studies of Au–Ru were performed using methods of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction spectroscopy (XRD). The voltammetric methods, including cyclic voltammetry (CV), differential pulse voltammetry (DPV) and direct amperometry, were used to analyze the composite’s electrochemical properties. The Au–Ru sensor exhibited two linear ranges of the non-enzymatic epinephrine detection: 0.01–10 μM and 10–1000 μM. The calculated sensitivities within these two ranges were 32.8 and 3.3 μA μM−1 cm−2, whereas the corresponding limits of detection were 9 and 20 nM, respectively. The Au–Ru sensor also revealed good stability and reproducibility, as well as high selectivity towards epinephrine detection in the presence of a number of the interfering species