抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Small Angle Scattering of X-Rays

わが国における成人市中肺炎原因微生物についてのsystematic review/meta‐analysis

We investigated the effects of inhibitors of clathrin-mediated endocytosis (chlorpromazine and K(+) depletion) and of caveolae-mediated uptake (filipin and genistein) on internalization of FITC-poly-l-lysine-labeled DOTAP/DNA lipoplexes and PEI/DNA polyplexes by A549 pneumocytes and HeLa cells and on the transfection efficiencies of these complexes with the luciferase gene. Uptake of the complexes was assayed by fluorescence-activated cell sorting. Lipoplex internalization was inhibited by chlorpromazine and K(+) depletion but unaffected by filipin and genistein. In contrast, polyplex internalization was inhibited by all four inhibitors. We conclude that lipoplex uptake proceeds only by clathrin-mediated endocytosis, while polyplexes are taken up by two mechanisms, one involving caveolae and the other clathrin-coated pits. Transfection by lipoplexes was entirely abolished by blocking clathrin-mediated endocytosis, whereas inhibition of the caveolae pathway had no effect. By contrast, transfection mediated by polyplexes was completely blocked by genistein and filipin but was unaffected by inhibitors of clathrin-mediated endocytosis. Fluorescence colocalization studies with a lysosomal marker, AlexaFluor-dextran, revealed that polyplexes taken up by clathrin-mediated endocytosis are targeted to the lysosomal compartment for degradation, while the polyplexes internalized via caveolae escape this compartment, permitting efficient transfection.

Role of clathrin- and caveolae-mediated endocytosis in gene transfer mediated by lipo- and polyplexes

A new family of materials comprised of cellulose, cellulose nanomaterials (CNMs), having properties and functionalities distinct from molecular cellulose and wood pulp, is being developed for applications that were once thought impossible for cellulosic materials. Commercialization, paralleled by research in this field, is fueled by the unique combination of characteristics, such as high on-axis stiffness, sustainability, scalability, and mechanical reinforcement of a wide variety of materials, leading to their utility across a broad spectrum of high-performance material applications. However, with this exponential growth in interest/activity, the development of measurement protocols necessary for consistent, reliable and accurate materials characterization has been outpaced. These protocols, developed in the broader research community, are critical for the advancement in understanding, process optimization, and utilization of CNMs in materials development. This review establishes detailed best practices, methods and techniques for characterizing CNM particle morphology, surface chemistry, surface charge, purity, crystallinity, rheological properties, mechanical properties, and toxicity for two distinct forms of CNMs: cellulose nanocrystals and cellulose nanofibrils.

/pdf/current-characterization-methods-for-cellulose-nanomaterials-1mwbef779r.pdf

Current characterization methods for cellulose nanomaterials

Modulating the zeta potential of cellulose nanocrystals using salts and surfactants

Gelation mechanism of cellulose nanofibre gels: A colloids and interfacial perspective.

Cellulose Nanocrystals (CNC) are explored to stabilize oil/water emulsions for their ability to adsorb at the oil/water interface In this work, the role of electrostatic forces in the CNC ability to stabilize oil/water emulsions is explored using canola oil/water and hexadecane/water as model systems Canola oil/water and Hexadecane/ water (20/80, v/v) emulsions were stabilized with the addition of CNCs using ultrasonication Emulsion droplet sizes range from 1 to 4 μm as measured by optical microscopy It is found that CNC can stabilize oil/water emulsions regardless of their charge density However, reducing the surface charge density, by adding salts and varying pH, can reduce the amount of CNC's required to form a stable emulsion Just by adding 3 mM Na+ or 1 mM or less Ca+2 to a CNC suspension, the amount of CNC reduced by 30% to stabilized 2 mL of Canola oil On the other hand, adding salt increases the emulsion volume The addition of 100 mM Na+ or the reduction of pH below 2 leads to the aggregation of CNC; emulsions formed under these conditions showed gel-like behavior This work shows the potential of nanocellulose crystal in stabilizing food and industrial emulsions This is of interest for applications where biodegradability, biocompatibility, and food grade requirements are needed

/pdf/pickering-emulsions-electrostatically-stabilized-by-7bt4tak7py.pdf

Pickering Emulsions Electrostatically Stabilized by Cellulose Nanocrystals

Surface-enhanced Raman scattering (SERS) has the theoretical possibility of detecting chemicals at the single molecular level. This potential is frequently limited, however, by the critical requirements of the surface morphology and mechanical stability of SERS substrates. In this paper, we report a new method for fabricating a SERS substrate with a significantly improved mechanical stability and analytical sensitivity, using cellulose nanofibers (CNFs) and gold nanoparticles (AuNPs). We constructed a uniformly CNFs-textured substrate on a glass surface by means of suppressing the “coffee ring” effect of the CNF sessile drop and then introduced an AuNP suspension onto the CNFs-textured substrate by taking advantage of the “coffee ring” effect. A widened detection zone is formed by AuNPs on the CNFs-textured glass, producing a stable SERS substrate for trace analysis and chemical identification. Microscopic and spectroscopic characterizations of the CNF-AuNPs SERS substrate show that the CNFs enhance the s...

Trace Analysis and Chemical Identification on Cellulose Nanofibers-Textured SERS Substrates Using the "Coffee Ring" Effect.

The exfoliation characteristics of graphite as a function of applied anodic potential (1–10 V) in combination with shear field (400–74 400 s–1) have been studied in a custom-designed microfluidic reactor. Systematic investigation by atomic force microscopy (AFM) indicates that at higher potentials thicker and more fragmented graphene sheets are obtained, while at potentials as low as 1 V, pronounced exfoliation is triggered by the influence of shear. The shear-assisted electrochemical exfoliation process yields large (∼10 μm) graphene flakes with a high proportion of single, bilayer, and trilayer graphene and small ID/IG ratio (0.21–0.32) with only a small contribution from carbon–oxygen species as demonstrated by X-ray photoelectron spectroscopy measurements. This method comprises intercalation of sulfate ions followed by exfoliation using shear induced by a flowing electrolyte. Our findings on the crucial role of hydrodynamics in accentuating the exfoliation efficiency suggest a safer, greener, and more...

Rico F. Tabor

Papers

Modulating the zeta potential of cellulose nanocrystals using salts and surfactants

Gelation mechanism of cellulose nanofibre gels: A colloids and interfacial perspective.

Pickering Emulsions Electrostatically Stabilized by Cellulose Nanocrystals

Trace Analysis and Chemical Identification on Cellulose Nanofibers-Textured SERS Substrates Using the "Coffee Ring" Effect.

Shear Assisted Electrochemical Exfoliation of Graphite to Graphene