200 research outputs found

    Влияние низкочастотной акустической обработки и присадок комплексного действия на реологические и энергетические параметры нефтей

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    В результате исследования получены новые данные по влиянию полимерных присадок и низкочастотной акустической обработки на вязкостно-температурные и энергетические характеристики высокопарафинистых нефтей различного состава. Установлена возможность применения комплексной физико-химической обработки нефтяных дисперсных систем, исходя из соотношения структурообразующих компонентов – парафинов и смолисто-асфальтеновых веществ.As a result of the research, new data on the effect of polymer additives and low-frequency acoustic processing on the viscosity-temperature and energy characteristics of high-paraffinic oils of various composition were obtained. The possibility of using complex physico-chemical treatment of oil dispersed systems is established, based on the ratio of the structure-forming components-paraffins and resinous-asphaltene substances

    Semiquantitative analysis of intrahepatic CC-chemokine mRNas in chronic hepatitis C.

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    BACKGROUND: The mechanisms leading to hepatic injury in chronic hepatitis C virus (HCV) infection are only incompletely understood. Recent data propose a correlation of the intrahepatic expression of the CC chemokine RANTES and the degree of periportal and portal inflammatory liver damage. AIM: Here, we have studied the intrahepatic mRNA levels of CC chemokines RANTES together with that of other members of this chemokine family (MIP-1beta, MCP-1, and MCP-2) in chronic hepatitis C as compared with healthy controls. METHODS: Liver samples from 22 HCV-infected patients, nine individuals with primary biliary cirrhosis and from 12 normal controls were included into this study. Intrahepatic mRNA levels of CC chemokines RANTES, MIP-1beta, MCP-1, and MCP-2 were analyzed by a semi-quantitative reverse transcription/real-time polymerase chain reaction assay. RESULTS: In chronic HCV infection, intrahepatic RANTES mRNA levels were significantly higher than in non-infected controls (7.2-fold, p < 0.001) or in the disease control group (2.8-fold, p < 0.001) and higher levels of RANTES mRNA levels were observed in livers with an advanced stage of liver cell injury (histologic activity index > or = 6), although this difference was not statistically significant (p = 0.08). In contrast, mRNA levels of MIP-1beta (p = 0.021) and MCP-1 (p = 0.021) were significantly lower in HCV liver samples while MCP-2 expression was similar in all groups analyzed. CONCLUSION: The data support the concept of chemokines as mediators of liver cell injury in chronic hepatitis C

    Percolation and Schramm-Loewner evolution in the 2D random-field Ising model

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    The presence of random fields is well known to destroy ferromagnetic order in Ising systems in two dimensions. When the system is placed in a sufficiently strong external field, however, the size of clusters of like spins diverges. There is evidence that this percolation transition is in the universality class of standard site percolation. It has been claimed that, for small disorder, a similar percolation phenomenon also occurs in zero external field. Using exact algorithms, we study ground states of large samples and find little evidence for a transition at zero external field. Nevertheless, for sufficiently small random field strengths, there is an extended region of the phase diagram, where finite samples are indistinguishable from a critical percolating system. In this regime we examine ground-state domain walls, finding strong evidence that they are conformally invariant and satisfy Schramm-Loewner evolution (SLEκSLE_{\kappa}) with parameter κ=6\kappa = 6. These results add support to the hope that at least some aspects of systems with quenched disorder might be ultimately studied with the techniques of SLE and conformal field theory

    A simple approach for detecting HLA-A02 alleles in archival formalin-fixed paraffin-embedded tissue samples and an application example for studying cancer immunoediting

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    The HLA system represents a central component of the antigen presentation machinery. As every patient possesses a defined set of HLA molecules, only certain antigens can be presented on the cell surface. Thus, studying HLA type-dependent antigen presentation can improve the understanding of variation in susceptibility to various diseases, including infectious diseases and cancer. In archival formalin-fixed paraffin-embedded (FFPE) tissue, the HLA type is difficult to analyze because of fragmentation of DNA, hindering the application of commonly used assays that rely on long DNA stretches. Addressing these difficulties, we present a refined approach for characterizing presence or absence of HLA-A*02, the most common HLA-A allele in the Caucasian population, in archival samples. We validated our genotyping strategy in a cohort of 90 samples with HLA status obtained by an NGS-based method. 90% (n = 81) of the samples could be analyzed with the approach. For all of them, the presence or absence of HLA-A*02 alleles was correctly determined with the method, demonstrating 100% sensitivity and specificity (95% CI: 91.40%-100% and 91.19%-100%). Furthermore, we provide an example of application in an independent cohort of 73 FFPE microsatellite-unstable (MSI) colorectal cancer samples. As MSI cancer cells encompass a high number of mutations in coding microsatellites, leading to the generation of highly immunogenic frameshift peptide antigens, they are ideally suited for studying relations between the mutational landscape of tumor cells and interindividual differences in the immune system, including the HLA genotype. Overall, our method can help to promote studying HLA type-dependency during the pathogenesis of a wide range of diseases, making archival and historic tissue samples accessible for identifying HLA-A*02 alleles.Peer reviewe

    No serological evidence for neuronal damage or reactive gliosis in neuro-COVID-19 patients with long-term persistent headache

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    Recent studies have indicated that long-term neurological sequelae after COVID-19 are not accompanied by an increase of canonical biomarkers of central nervous system injury in blood, but subgroup stratifications are lacking. This is a particular concern in chronic headache, which can be a leading symptom of Post-COVID diseases associated with neuronal damage such as vasculitis or autoimmune encephalitis. We here compared patients with mild Post-COVID-19 syndrome and persistent headache (persistent Post-COVID-19 headache) lasting longer than 12 weeks after the initial serological diagnosis, to patients with mild and severe COVID-19 and COVID-19-negative controls. Levels of neurofilament light chain and glial fibrillary astrocytic protein, i.e. markers of neuronal damage and reactive astrogliosis, were lower in blood from patients with persistent Post-COVID-19 headache compared to patients with severe COVID-19. Hence, our pilot serological study indicates that long-term Post-COVID-19 headache may not be a sign of underlying neuronal damage or neuroinflammation

    Early detection of duodenal cancer by upper gastrointestinal-endoscopy in Lynch syndrome

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    Small bowel cancer (SBC) is the malignancy with the highest standardized incidence ratio in Lynch syndrome (LS) patients. Of all SBCs, about 50% are duodenal cancers (DCs), therefore being accessible by esophago-gastro-duodenoscopy (EGD) for surveillance. We asked whether early detection of DC is possible for LS patients undergoing surveillance by EGD and if surveillance should be limited to specific subgroups. Data for LS patients with DC were retrieved from the registry of the German Consortium for Familial Intestinal Cancer. Patients undergoing active surveillance by EGDs (surveillance group) were compared to those who did not (nonsurveillance group) regarding tumor stage at diagnosis. Union for International Cancer Control stages I-IIA were defined as early stage disease and IIB-IV as advanced stage disease. Statistical analysis was performed using Fisher's exact test. Among 2015 patients with pathogenic variants in any mismatch-repair-gene, 47 patients with 49 DCs were identified. In 10% of cases, patients were under 35 years at diagnosis; family and personal tumor history did not correlate with DC diagnosis. Pathogenic germline variants in MSH6, PMS2 or EPCAM were present in 10% of patients. Statistical analysis could be performed on 13 DC patients in the surveillance group and 14 in the nonsurveillance group. Early detection was possible for 71% of patients in the surveillance group and 29% of patients in the nonsurveillance group (P = .021). Early detection of DC by EGD in LS patients is feasible regardless of family history, mutational status and should start no later than 25 years of age
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