Preparative Scale Production of Recombinant Human Transthyretin for Biophysical Studies of Protein-Ligand and Protein-Protein Interactions

Human transthyretin (hTTR), a serum protein with a main role in transporting thyroid hormones and retinol through binding to the retinol-binding protein, is an amyloidogenic protein involved in familial amyloidotic polyneuropathy (FAP), familial amyloidotic cardiomyopathy, and central nervous system selective amyloidosis. hTTR also has a neuroprotective role in Alzheimer disease, being the major Aβ binding protein in human cerebrospinal fluid (CSF) that prevents amyloid-β (Aβ) aggregation with consequent abrogation of toxicity. Here we report an optimized preparative expression and purification protocol of hTTR (wt and amyloidogenic mutants) for in vitro screening assays of TTR ligands acting as amyloidogenesis inhibitors or acting as molecular chaperones to enhance the TTR:Aβ interaction. Preparative yields were up to 660 mg of homogenous protein per L of culture in fed-batch bioreactor. The recombinant wt protein is mainly unmodified at Cys10, the single cysteine in the protein sequence, whereas the highly amyloidogenic Y78F variant renders mainly the S-glutathionated form, which has essentially the same amyloidogenic behavior than the reduced protein with free Cys10. The TTR production protocol has shown inter-batch reproducibility of expression and protein quality for in vitro screening assays.     

多层合采油藏最大有效井径数学模型及精确解

The maximum effective hole-diameter mathematical model describing the flow of slightly compressible fluid through a commingled reservoir was solved rigorously with consideration of wellbore storage and different skin factors. The exact solutions for wellbore pressure and the production rate obtained from layer j for a well production at a constant rate from a radial drainage area with infinite and constant pressure and no flow outer boundary condition were expressed in terms of ordinary Bessel functions. These solutions were computed numerically by the Crump‘‘s numerical inversion method and the behavior of systems was studied as a function of various reservoir parameters. The model was compared with the real wellbore radii model. The new model is numerically stable when the skin factor is positive and negative, but the real wellbore radii model is numerically stable only when the skin factor is positive.     

Maximum Effective Hole Mathematical Modei and Exact Solution for Commingled Reservoir

The maximum effective hole-diameter mathematical modei describing the flow of slightly compressible fluid through a commingled reservoir was solved rigorously with consideration of wellbore storage and different skin factors. The exact solutions for wellbore pressure and the production rate obtained from layer j for a well production at a constant rate from a radial drainage area with infinite and constant pressure and no flow outer boundary condition were expressed in terms of ordinary Bessel functions. These solutions were computed numerically by the Crump's numerical inversion method and the behavior of systems was studied as a function of various reservoir parameters. The modei was compared with the real wellbore radii modei. The new modei is numerically stable when the skin factor is positive and negative, but the real wellbore radii modei is numerically stable only when the skin factor is positive.     

A Novel Method of Endotoxins Removal from Chitosan Hydrogel as a Potential Bioink Component Obtained by CO2 Saturation

The article presents a new approach in the purification of chitosan (CS) hydrogel in order to remove a significant amount of endotoxins without changing its molecular weight and viscosity. Two variants of the method used to purify CS hydrogels from endotoxins were investigated using the PyroGene rFC Enzymatic Cascade assay kit. The effect of the CS purification method was assessed in terms of changes in the dynamic viscosity of its hydrogels, the molecular weight of the polymer, microbiological purity after refrigerated storage and cytotoxicity against L929 cells based on the ISO 10993-5:2009(E) standard. The proposed purification method 1 (M1) allows for the removal of significant amounts of endotoxins: 87.9–97.6% in relation to their initial concentration in the CS hydrogel without affecting the solution viscosity. Moreover, the final solutions were sterile and microbiologically stable during storage. The M1 purification method did not change the morphology of the L929 cells.     

海南岛能源植物资源及其利用潜力

作者根据在过去近30年的调查研究资料,汇总了海南岛38科67属88种生物能源植物资源的基本情况.对这些能源植物在种子、种仁、果实、树叶或茎/根的含油(或碳氢化合物)部位及含油率,在工业和民用方面的用途进行分析.着重对麻疯树、绿玉树、油楠、硬核、牛角瓜5种有开发价值的种类进行分述,分析了这5个种类在海南岛的生态适应性和作为油料潜在的利用价值.最后,对海南热带地区生物能源的产业发展提出了建议:1)摸清海南岛热带野生生物能源植物资源种类和储量;2)筛选优良种质品系;3)开展栽培技术的研究;4)建立产业化基地.     

R-Curve for a Lead Zirconate Titanate Ceramic Obtained from Tensile Strength Tests with Knoop-Damaged Specimens

A procedure was used that made it possible to determine the R -curve for piezoelectric ceramics from tensile strength tests conducted with Knoop-damaged specimens. The resulting crack-tip toughness K _I0 was 0.6 MPa·m^1/2, and the R -curve starting from this value increased to 1.4 MPa·m^1/2 within a 0.7 mm crack extension.     

Preparation of Silica Gel Obtained from Early Cretaceous Sidi Aich Sands (Central Tunisia) and its Potential to Remove Pollutant Dye Anionic from Wastwaters

Silicon - The present study concerns the elimination by retention of the anionic dye orange II (OII) from aqueous solutions was studied using a silica gel prepared from Tunisian silica sands...     

某热电厂能源利用状况及节能潜力分析的案例实践

天津某热电厂针对采暖期能源使用情况开展了能源审计工作。审计期,企业综合能耗为46941.60tce(当量值),供热煤耗为37.54kgce/GJ,供电煤耗为357.70gce/kW·h,发电煤耗为280.66gce/kW·h,综合厂用电率为20.89%,能源总成本为12280.17万元/年,占总生产成本的45%。企业节能潜力折合标准煤当量值5564.22tce/a,产生节能效益675.92万元/年。     

Exact solutions for a class of heat and mass transfer problems

A number of heat and mass transfer problems of chemical engineering interest involve the convective diffusion equation of the form where θ = θ(X₁, X₂). Exact solutions for such problems are developed in terms of well-known functions which have been thoroughly studied in recent years. Several problems which have appeared in the literature, solved by completely numerical methods, are re-examined and new problems are discussed and solved. The results of the present analysis are compared with those obtained by other methods where possible. The problem of axial diffusion of heat or mass is solved in terms of known functions. The present formulation is shown to be particularly useful in the analysis of conjugated boundary value problems, i. e. for problems involving heat or mass transfer across an interface where the interfacial boundary condition is not known a priori but is related to the temperature or concentration fields in the adjacent phases.     

Stromal Interactions as Regulators of Tumor Growth and Therapeutic Response: A Potential Target for Photodynamic Therapy?

It has become increasingly widely recognized that the stroma plays several vital roles in tumor growth and development and that tumor-stroma interactions can in many cases account for poor therapeutic response. Inspired by an emerging body of literature, we consider the potential role of photodynamic therapy (PDT) in targeting interactions with stromal fibroblasts and mechanosensitive signaling with the extracellular matrix as a means to drive tumors toward a more therapeutically responsive state and synergize with other treatments. This concept is particularly relevant for cancer of the pancreas, which is characterized by tumors with a profoundly dense, rigid fibrous stroma. Here we introduce new in vitro systems to model interactions between pancreatic tumors and their mechanical microenvironment and restore signaling with stromal fibroblasts. Using one such model as a test bed it is shown here that PDT treatment is able to destroy fibroblasts in an in vitro 3D pancreatic tumor-fibroblast coculture. These results and the literature suggest the further development of PDT as a potential modality for stromal depletion.     

Metal-Ceramic Interactions:IV, Absolute Measurement of Metal-Ceramic Interfacial Energy and the Interfacial Adsorption of Silicon from Iron-Silicon Alloys

The surface and interfacial energies in the system Ni-A1₂O₃ md Ni-ZrO₂ were determined at elevated temperatures by means of equilibrium interfacial angle measurements. Coincidental measurements of surface tension and contact angle for iron and iron-silicon alloys in Al₂O₃ give values of interfacial energy. Application of Gibbs' isotherm indicates that interfacial adsorption of silicon takes place in this system.     

On the Estimations of Micelle-Water Partition Constants for Solutes from Their Octanol-Water Partition Constants,Normal Boiling Points,Aqueous Solubilities,and Group and Bond Contribution Schemes

Abstract

Five different estimation procedures for micelle-water partition constants for organic solutes are discussed. The procedures are based on 1) knowledge of octanol-water partition constants for the solutes, 2) aqueous solubilities of the solutes, 3) normal boiling points of the solutes, 4) a bond contribution scheme, and 5) a group contribution scheme. Available data in the literature including our own are used in obtaining these correlations. Potential advantages and drawbacks of each of the methods are explored.     

Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well

In the framework of effective-mass envelope function theory, including the effect of Rashba spin-orbit coupling, the binding energy E _b and spin-orbit split energy Г of the ground state of a hydrogenic donor impurity in AlGaN/GaN triangle-shaped potential heterointerface are calculated. We find that with the electric field of the heterojunction increasing, (1) the effective width of quantum well [`(\textW)] \overline{\text{W}} decreases and (2) the binding energy increases monotonously, and in the mean time, (3) the spin-orbit split energy Г decreases drastically. (4) The maximum of Г is 1.22 meV when the electric field of heterointerface is 1 MV/cm.     

Effective density and volatility of particles sampled from a helicopter gas turbine engine

The effective density and size-resolved volatility of particles emitted from a Rolls-Royce Gnome helicopter turboshaft engine are measured at two engine speed settings (13,000 and 22,000 RPM). The effective density of denuded and undenuded particles was measured. The denuded effective densities are similar to the effective densities of particles from a gas turbine with a double annular combustor as well as a wide variety of internal combustion engines. The denuded effective density measurements were also used to estimate the size and number of primary particles in the soot aggregates. The primary particle size estimates show that the primary particle size was smaller at lower engine speed (in agreement with transmission electron microscopy analysis). As a demonstration, the size-resolved volatility of particles emitted from the engine is measured with a system consisting of a differential mobility analyzer, centrifugal particle mass analyzer, condensation particle counter, and catalytic stripper. This system determines the number distributions of particles that contain or do not contain non-volatile material, and the mass distributions of non-volatile material, volatile material condensed onto the surface of non-volatile particles, and volatile material forming independent particles (e.g., nucleated volatile material). It was found that the particulate at 13,000 RPM contained a measurable fraction of purely volatile material with diameters below ～25 nm and had a higher mass fraction of volatile material condensed on the surface of the soot (6%–12%) compared to the 22,000 RPM condition (1%–5%). This study demonstrates the potential to quantify the distribution of volatile particulate matter and gives additional information to characterize sampling effects with regulatory measurement procedures.

Copyright © 2017 American Association for Aerosol Research     

The Use of AFM and Surface Energy Measurements to Investigate Drug-Canister Material Interactions in a Model Pressurized Metered Dose Inhaler Formulation

The aim of the project was to investigate the interactions between micronized salbutamol sulphate, budesonide, and formoterol fumarate dihydrate and different canister surfaces materials (Aluminium, anodized aluminium, perfluoroalkoxy, fluorinated ethylene propylene—polyether sulphone, and polytetrafluoroethylene) used in pressurized metered dose inhalers (pMDIs).

The surface component approach for polar and apolar interfacial interactions was used to predict the adhesion behavior of micronized drugs with the inner surfaces of pMDI canisters. This was achieved using a combination of in situ colloid probe atomic force microscopy (AFM) measurements and theoretical treatment of the surface free energy measurements, via a contact angle–based technique of the interacting surfaces.

All three drugs exhibited similar dispersive surface energy free values. A greater variation was, however, found in the polar component of the surface free energy measurements. These results were also reflected in the dispersive and polar components of the canister materials. Moreover, the linear relationship between the work of adhesion and AFM measured adhesion was shown to be correlated on the polar contributions of the surface free energies of the interacting materials. AFM measurements indicated that salbutamol sulphate was found to have the strongest adhesive forces with respect to the canister surface materials while budesonide and formoterol fumarate dihydrate appeared to have similar adhesive characteristics. The present study suggests that investigations into the design and characterization of pMDI formulations would benefit from considerations of the polar contribution of the surface free energy and relative work of adhesion of the drug and various components of a pMDI system.     

偏三甲苯异构化产品粗均三甲苯的分离计算

计算了从偏三甲苯异构化产品分离均三甲苯的单塔、双塔、三塔工艺流程及工艺条件，结果表明，不同流程均能得到合格的均三甲苯产品。