Clonal analysis of intrahepatic B cells from HCV-infected patients with and without mixed cryoglobulinemia

Clonal rearrangements of Ig heavy chain (IgH) genes and hepatitis C virus (HCV) genomic sequences were assayed on intrahepatic B lymphocytes isolated from HCV chronically infected patients with and without type II mixed cryoglobulinemia (MC). Liver tissue samples from eight patients with and nine without MC were subjected to routine histologic studies, immunophenotyping, and genotypic analysis including IgH V-D-J region gene rearrangements by PCR. RT-PCR, signal amplification by branched DNA assay, and in situ hybridization technique were used to detect and quantitate HCV RNA genomic sequences in selected B cells purified from each tissue sample. Although HCV infection of intrahepatic B cells was shown in all patients both with and without MC, frank B cell monoclonal and oligoclonal patterns were found in only three and four patients with MC, respectively. No monoclonal profile was seen in the noncryoglobulinemic patients, whereas an oligoclonal profile was demonstrated in four of them. No clonalities were shown in HCV-unrelated patients matched for age and severity of liver disease. No obvious difference in HCV genotype distribution was found in relation to the clonal expansion profile. Noncryoglobulinemic patients showing clonal expansion in liver tissue had higher titers of serum rheumatoid factor (RF). Spontaneous production of RF was shown in cell cultures of intrahepatic B cells, suggesting their persistent stimulation in vivo. These data indicate that HCV infection of B cells and B cell clonal expansions occur in the liver microenvironment and preferentially involve RF-producing cells.     

Impaired platelet production of nitric oxide predicts presence of acute coronary syndromes

BACKGROUND: Thrombus formation within a coronary vessel is the acute precipitating event in most acute coronary syndromes. Recently, constitutive nitric oxide synthase (cNOS) has been identified in human platelets, and platelet-derived nitric oxide has been shown to inhibit platelet recruitment after aggregation. However, its role in regulating platelet responses under normal or pathologic conditions has not yet been elucidated. METHODS and RESULTS: We examined nitric oxide (NO) production by platelets isolated from 87 patients undergoing coronary angiography, 37 with stable angina and 50 with unstable angina or a myocardial infarction within 2 weeks. After stimulation with 5 micromol/L ADP, platelet aggregation and NO production were simultaneously measured with an NO-selective microelectrode adapted for use in a standard platelet aggregometer. Mean (+/-SEM) platelet-derived NO production was 1.78+/-0.36 pmol/10(8) and 0.26+/-0.05 pmol/10(8) platelets in coronary patients with stable angina and acute coronary syndromes, respectively (P=0. 0001). By logistic regression analysis, heparin treatment (odds ratio 6.6, CI 1.9 to 22.8, P=0.003), lower platelet-NO production (odds ratio 4.0, CI 1.3 to 11.5, P=0.01), and extent of atherosclerosis (odds ratio 1.5, CI 1.1 to 2.0, P=0.02) were independent predictors of an acute coronary syndrome. In the subset of patients with angiographic evidence of atherosclerosis (n=83), logistic regression demonstrated that platelet NO production (odds ratio 3.9, CI 1.3 to 11.1, P=0.01) and heparin treatment (odds ratio 6.4, CI 1.9 to 22.0, P=0.004) were independent predictors of an acute coronary syndrome, whereas extent of atherosclerosis was not. CONCLUSIONS: In summary, aggregating platelets from patients with acute coronary syndromes produce less NO. Since platelet aggregation and thrombus formation are implicated in unstable angina and myocardial infarction, impaired platelet-derived NO production may contribute to the development of acute coronary syndromes.     

Alginate and alginate/hyaluronic acid membranes generated by electrospinning in wet conditions: Relationship between solution viscosity and spinnability

The methodology to create alginate and alginate/hyaluronic acid membranes, which involves wet conditions electrospinning, is presented in this paper. The wet conditions allow simultaneously to work in water solutions avoiding the toxic solvents and to obtain crosslinked alginate. An accurate rheological characterization of all solutions examined is performed. By optimizing the electrospinning parameters, it is possible to obtain alginate membranes with homogeneous nanofibers and a narrow diameter distribution (i.e., around 100 nm) as well as alginate/hyaluronic acid membranes characterized by a network of bimodal distribution of the dimensions, namely nanofibers with a diameter comparable to the ones of the alginate membrane, in which are blocked microfibers with a ribbon like appearance, as observed in the SEM images. In order to facilitate the electrospinning process, poly(ethylene oxide) is added to the solutions and then removed after membranes preparation, as demonstrated by the differential scanning calorimetry results, obtaining membranes made up only biopolymers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46390.     

Nanoparticles from polylactide and polyether block copolymers: formation, properties, encapsulation, and release of pyrene--fluorescent model of hydrophobic drug

Polylactide-b-polyglycidol-b-poly(ethylene oxide) terpolymers and their derivatives with carboxyl and 4-(phenylazo)phenyl labels in polyglycidol blocks were used for formation of nanoparticles. Nanoparticles were produced by self assembly of terpolymer macromolecules in water above the critical aggregation concentration and by dialysis of terpolymer solutions in 1,4-dioxane against water. For terpolymers with 4-(phenylazo)phenyl labels critical aggregation concentrations increased after irradiation with UV light (300 < lambda < 400 nm) inducing conformational change of the label from trans- to cis-conformation. Diameters of nanoparticles obtained by self-assembly of macromolecules ranged from 20 to 44 nm. Dialysis yielded nanoparticles with bimodal diameter distribution. One fraction had diameters below 35 nm and diameters of the second fraction were in a range from 350 to 2300 nm, depending on terpolymer structure. Mixtures of terpolymers with poly(L,L-lactide) and poly(D,D-lactide) blocks yielded nanoparticles with diameters from 350 to 440 nm. Pyrene was incorporated into nanoparticles by partition between solution and nanoparticles or directly during particle formation by dialysis. Monitoring of pyrene release from nanoparticles suggests that a fraction of this compound was entrapped into the polylactide core whereas the remaining one was located in the polyether rich shell. The release from shells is faster for nanoparticles made from copolymers with carboxyl labels in polyglycidol blocks.     

采用实际模型对自动齿轮箱凸轮作动器的效率和磨损的研究

本文研究自动齿轮箱凸轮作动器的效率和磨损,着重于接触动力学。采用罚函数方法仿真凸轮和从动杆间接触,该模型基于有限元与连续弹性基础梁理论近似。采用Hertz理论考虑凸轮和从动杆间相对运动时主要曲率的变化计算基础模量。为比较接触力和不同凸轮轮廓的磨损,该模型仿真概括了整个档位。     

Transmission network-based energy and environmental assessment of plug-in hybrid electric vehicles

The introduction of plug-in hybrid electric vehicles (PHEVs) is expected to have a significant impact on regional power systems and pollutant emissions. This paper analyzes the effects of various penetrations of PHEVs on the marginal fuel dispatch of coal, natural gas and oil, and on pollutant emissions of CO₂, NO_x, SO₂ in the New York Metropolitan Area for two battery charging scenarios in a typical summer and winter day. A model of the AC transmission network of the Northeast Power Coordinating Council (NPCC) region with 693 generators is used to realistically incorporate network constraints into an economic dispatch model. A data-based transportation model of approximately 1 million commuters in NYMA is used to determine battery charging pattern. Results show that for all penetrations of PHEVs network-constrained economic dispatch of generation is significantly more realistic than unconstrained cases. Coal, natural gas and oil units are on the margin in the winter, and only natural gas and oil units are on the margin in the summer. Hourly changes in emissions from transportation and power production are dominated by vehicular activity with significant overall emissions reductions for CO₂ and NO_x, and a slight increase for SO₂. Nighttime regulated charging produces less overall emissions than unregulated charging from when vehicles arrive home for the summer and vice versa for the winter. As PHEVs are poised to link the power and transportation sectors, data-based models combining network constraints and economic dispatch have been shown to improve understanding and facilitate control of this link.     

Syngas production by steam and oxy-steam reforming of biogas on monolith-supported CeO2-based catalysts

In this study, the syngas production by steam reforming (SR) and oxy-steam reforming (OSR) of clean biogas over cordierite monoliths (400 cpsi) lined with Ni, Rh, or Pt on CeO₂ catalyst was deeply investigated. Structured catalysts were prepared by using an alternative method to traditional washcoating based on the combination of the solution combustion synthesis (SCS) with the wetness impregnation (WI) technique. TEM and SEM analysis were used to study the morphology of the catalytic layer and to determine its thickness, while the quality of the coating in terms of adhesion on the monolith was evaluated by ultrasonic treatment in isopropyl alcohol solution. The performance and the stability of the structured catalysts were investigated at different process parameters, namely temperature (700–900 °C), steam-to-carbon (S/C = 1–5) and oxygen-to-carbon (O/C = 0.1–0.2) molar ratios, and weight space velocity (WSV = 30,000–250,000 NmL g_cat^?1 h^?1). The SCS + WI deposition method allowed obtaining a uniform and thin coated layer with high mechanical strength. The following order of activity was exploited: Rh > Pt > Ni for biogas SR and Rh > Pt ≈ Ni for biogas OSR. The Rh-based catalyst exhibited higher activity and long-lasting stability towards biogas SR and OSR reactions for syngas production.