Modulation of TcR/CD3-zeta chain expression by a circulating factor derived from ovarian cancer patients

In women with ovarian cancer, suppression of components of the immune system may promote tumour development. Previous studies in ovarian cancer have demonstrated that decreased expression and function of the T-cell receptor (TcR)-associated signal transducing zeta-chain correlates with deficient immune responsiveness of T cells. In this study, sera and ascitic fluids obtained from woman with advanced ovarian cancer were found to suppress the expression of TcR-associated zeta chain. This suppression of zeta chain expression was dose-dependent and was not observed with biologic fluids obtained from healthy women. © 2001 Cancer Research Campaign http://www.bjcancer.co

Biodiesel production from jatropha seeds: Solvent extraction and in situ transesterification in a single step

The objective of this study was to investigate solvent extraction and in situ transesterification in a single step to allow direct production of biodiesel from jatropha seeds. Experiments were conducted using milled jatropha seeds, and n-hexane as extracting solvent. The influence of methanol to seed ratio (2:1–6:1), amount of alkali (KOH) catalyst (0.05–0.1 mol/L in methanol), stirring speed (700–900 rpm), temperature (40–60 °C) and reaction time (3–5 h) was examined to define optimum biodiesel yield and biodiesel quality after water washing and drying. When stirring speed, temperature and reaction time were fixed at 700 rpm, 60 °C and 4 h respectively, highest biodiesel yield (80% with a fatty acid methyl ester purity of 99.9%) and optimum biodiesel quality were obtained with a methanol to seed ratio of 6:1 and 0.075 mol/L KOH in methanol. Subsequently, the influence of stirring speed, temperature and reaction time on biodiesel yield and biodiesel quality was studied, by applying the randomized factorial experimental design with ANOVA (F-test at p = 0.05), and using the optimum values previously found for methanol to seed ratio and KOH catalyst level. Most experimental runs conducted at 50 °C resulted to high biodiesel yields, while stirring speed and reaction time did not give significantly effect. The highest biodiesel yield (87% with a fatty acid methyl ester purity of 99.7%) was obtained with a methanol to seed ratio of 6:1, KOH catalyst of 0.075 mol/L in methanol, a stirring speed of 800 rpm, a temperature of 50 °C, and a reaction time of 5 h. The effects of stirring speed, temperature and reaction time on biodiesel quality were not significant. Most of the biodiesel quality obtained in this study conformed to the Indonesian Biodiesel Standard

Tumour-derived exosomes and their role in cancer-associated T-cell signalling defects

Dendritic and lymphoid ‘exosomes' regulate immune activation. Tumours release membranous material mimicking these ‘exosomes,' resulting in deletion of reactive lymphocytes. Tumour-derived ‘exosomes' have recently been explored as vaccines, without analysis of their immunologic consequences. This investigation examines the composition of tumour-derived ‘exosomes' and their effects on T lymphocytes. Membranous materials were isolated from ascites of ovarian cancer patients (n=6) and Western immunoblotting was performed for markers associated with ‘exosomes.' Using cultured T cells, ‘exosomes' were evaluated for suppression of CD3-ζ and JAK 3 expressions and induction of apoptosis, measured by DNA fragmentation. ‘Exosome' components mediating suppression of CD3-ζ were isolated by continuous eluting electrophoresis and examined by Western immunoblotting. ‘Exosomes' were shown to be identical with previously characterised shed membrane vesicles by protein staining and TSG101 expression. ‘Exosomes' expressed class I MHC, placental alkaline phosphatase, B23/nucleophosmin, and FasL. ‘Exosomes' suppressed expression of T-cell activation signalling components, CD3-ζ and JAK 3 and induced apoptosis. CD3-ζ suppression was mediated by two components: 26 and 42 kDa. Only the 42 kDa component reacted with anti-FasL antibody. These results indicate that, while ‘exosomes' express tumour antigens, leading to their proposed utility as tumour vaccines, they also can suppress T-cell signalling molecules and induce apoptosis

Increased charcoal yield & production of lighter oils from the slow pyrolysis of biomass

In an effort to reduce CO2 emissions from solid fuels, a considerable amount of research is going into how improve the manufacturing processes and product properties of the products from pyrolysis. One aspect that is often overlooked is the production of charcoal for cooking and soil remediation, which is an inefficient conversion process. There is considerable interest into using additives to increase charcoal yields, and based on the observation from fast pyrolysis work that certain catalyst tar cracking pathways can deposit considerable amounts of coke on the surface of the catalyst, there is a potential application to slow pyrolysis processes producing charcoal. Alumino-silicate catalysts have been shown to have a relatively high tendency to do this. This work hypothesises that this catalysation can be applied to slow pyrolysis, with low cost alumino-silicate minerals, specially bentonite clay, which has been added to pine pyrolysis in concentrations up to 60% wt (against input biomass) at temperatures 300–700 °C. This study has shown that the use of bentonite clay minerals can be beneficial to the process, as there is an increase in the charcoal yield from biomass, whilst the proximate analysis of the charcoal shows little change from levels expected from biomass only pyrolysis. The conversion of oil to charcoal was more effective at high temperatures due to higher levels of oil cracking. At 700 °C with 60% clay loading, charcoal yield increased 16%wt (dry ash free basis) was seen, while at the same time 19% extra gas was produced at the expense of 35% of the oil from raw pine pyrolysis. This indicates fuel properties of the charcoal are predictable, and changes in yield considerable. At the same time, the abundance of lower molecular weight oils is increased (relative to 4-methyl phenol). It is though that pyrolysis oil reacts with the clay, causing the heavier tars to disproportionate into charcoal and gas

New Renewable and Biodegradable Particleboards from Jatropha Press Cakes

The influence of thermo-pressing conditions on the mechanical properties of particleboards obtained from Jatropha press cakes was evaluated in this study. Conditions such as molding temperature and press cake oil content were included. All particleboards were cohesive, with proteins and fibers acting respectively as binder and reinforcing fillers. Generally, it was the molding temperature that most affected particleboard mechanical properties. The most resistant boards were obtained using 200°C molding temperature. Glass transition of proteins then occurred during molding, resulting in effective wetting of the fibers. At this optimal molding temperature, the best compromise between flexural properties (7.2 MPa flexural strength at break and 2153 MPa elastic modulus), Charpy impact strength (0.85 kJ/m²) and Shore D surface hardness (71.6°), was a board obtained from press cake with low oil content (7.7%). Such a particleboard would be usable as interlayer sheets for pallets, for the manufacture of containers or furniture, or in the building trade

SULFONATED POLY(ARYLENE ETHER BENZIMIDAZOLE) COPOLYMER MEMBRANE SYNTHESIS AND CHARACTERIZATION

Hidrojenden elektrik enerjisi üretiminde kullanılan yakıt hücreleri, geleceğin çevre dostu ve yüksek verimli enerji üretimine alternatif olarak kabul görmektedirler. Nafion gibi perflorosülfonik asit bazlı membranlar polimer elektrolit membran yakıt hücreleri (PEMHY)’nde sıklıkla kullanılmaktadırlar. Ancak Nafion membranların yüksek sıcaklıklarda proton iletkenliklerinin düşmesi ve fiyatlarının yüksek olması nedeniyle alternatif polimer elektrolit membran (PEM)’lar üzerine araştırmalar devam etmektedir. Bu çalışmanın ilk aşamasında, disodyum-3,3’-disülfonat-4,4’-diklorodifenilsülfon (SDCDPS) ve benzimidazol bisfenol (HPBI) monomerlerinin sentezi gerçekleştirilmiştir. Daha sonra sentezlenen monomerlerden nükleofilik aromatik polikondenzasyon reaksiyonu ile poli(arilen eter benzimidazol) kopolimeri sentezlenmiştir. Sentezlenen monomerlerin 1H NMR ve FTIR, kopolimerin ise 1H NMR, FTIR ve termogravimetrik analizleri (TGA) gerçekleştirilmiştir. Yapılan analizler sonucunda kopolimerin sentezlendiği açıkça ortaya konulmuştur. TGA eğrisi sentezlenen kopolimerin ısıl kararlılığının yüksek olduğunu (~400 oC) ve yüksek sıcaklık uygulamalarında kullanılabilirliğini göstermişti

KİRAZ ÇEKİRDEĞİNDEN GRANÜL AKTİF KARBON ÜRETİMİ

Bu çalışmada, bitkisel bir atık olan kiraz çekirdekleri granül aktif karbon üretimi amacıyla hammadde olarak kullanılmıştır. Meyve suyu üretimi yapan bir tesisten alınan çekirdekler, ön işlemlerden geçirildikten sonra potasyum karbonat kullanılarak aktive edilmiş ve karbonizasyon işlemine tabi tutulmuşlardır. Üretilen karbonun etkinliği, sulu çözeltiden boyar madde giderimi ile test edilmiştir. Granüler şekilde hazırlanmış olan aktif karbon kullanılarak sulu çözeltiden boyar madde gideriminde çözelti pH’ının ve karıştırma süresinin etkisi incelenmiştir. Ayrıca adsorpsiyon sisteminin Langmuir izoterm modeline uyum sağladığı görülmüştür

Polymer Electrolyte Membrane Fuel Cell Performance of a Sulfonated Poly(Arylene Ether Benzimidazole) Copolymer Membrane

Disodium-3,3′-disulfonate-4,4′-dichlorodiphenylsulfone (SDCDPS) and 5,5′-bis[2-(4-hydroxyphenyl)benzimidazole] (HPBI) monomers were synthesized. Binding these monomers via nucleophilic aromatic polycondensation reaction, a sulfonated poly(arylene ether benzimidazole) copolymer was synthesized. Structures of monomers and copolymer were confirmed by proton nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared (FTIR) spectroscopy analyses. Proton exchange membrane was prepared by dissolving copolymer in dimethylacetamide (DMAc) and casting onto a glass plate. Copolymer membrane was doped with sulfuric acid to ensure proton exchange character. Single cell performance of the copolymer membrane was tested in a polymer electrolyte membrane fuel cell test station. The highest power density of the membrane was measured as 23.7 mW cm−2 at 80°C. Thermogravimetric analysis (TGA) showed that as the degree of disulfonation is increased thermal stability of the copolymer is increased