669 research outputs found

    Studies on a Factor Enhancing Colicin E3 Activity In Vitro

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    Adiposity and carotid atherosclerosis in two populations at very different risk of cardiovascular mortality: Norway and Russia

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    Obesity is a key risk factor for cardiovascular disease (CVD). The aim of this PhD study was to investigate the associations of obesity and adiposity with carotid atherosclerosis, and, in particular, to examine the effect of general vs abdominal adiposity on the burden of carotid plaque. These associations were investigated in the Tromsø study in Norway and in the Know Your Heart study in Russia. These populations have very different cardiovascular mortality rates, with Russia having one of the highest rates in the world. In this context, the thesis looked at whether differences in carotid plaque burden between these populations can be explained by adiposity. Four anthropometric measures of adiposity were included, which involved body mass index, waist circumference, waist-to-hip ratio, and waist-to-height ratio. Carotid plaque burden, i.e. the presence of plaques, number of plaques, and total plaque area (TPA), was assessed using carotid ultrasound. In the Tromsø Study 5th survey (2001), there was strong evidence of an association between TPA and adiposity, especially abdominal adiposity, after adjustment for potential confounders (sex, smoking status, education). This association was largely mediated by cardio-metabolic CVD risk factors (blood pressure, cholesterol, glycosylated haemoglobin). These findings were confirmed in a prospective analysis assessing changes in plaque burden between the Tromsø Study 4th (1994-95) and 5th surveys. Comparison of the cross-sectional results from the Know Your Heart study (KYH) and Tromsø Study 7th wave (Tromsø 7) showed that women in KYH had higher levels of adiposity than in Tromsø 7, while levels were similar for men. Despite evidence that adiposity was associated with carotid plaque (presence of plaques and number of plaques), adiposity failed to explain the high burden of carotid plaque in KYH compared to Tromsø 7 in women as well as men. Explanations for the greater carotid plaque burden in Russia must be sought elsewhere, although reducing levels of obesity in Russia and Norway must be a priority for other reasons

    Transmission of mitochondrial plasmids in protoplast cell fusion between compatible monokaryons of Lentinula edodes

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    The original publication is available at www.springerllink.com.ArticleJOURNAL OF WOOD SCIENCE. 53(3): 264-267 (2007)journal articl

    Self-assembled monolayer of light-harvesting core complexes of photosynthetic bacteria on an amino-terminated ITO electrode

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    Light-harvesting antenna core (LH1-RC) complexes isolated from Rhodospirillum rubrum and Rhodopseudomonas palustris were successfully self-assembled on an ITO electrode modified with 3-aminopropyltriethoxysilane. Near infra-red (NIR) absorption, fluorescence, and IR spectra of these LH1-RC complexes indicated that these LH1-RC complexes on the electrode were stable on the electrode. An efficient energy transfer and photocurrent responses of these LH1-RC complexes on the electrode were observed upon illumination of the LH1 complex at 880 nm

    Boron microlocalization in oral mucosal tissue: implications for boron neutron capture therapy

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    Clinical studies of the treatment of glioma and cutaneous melanoma using boron neutron capture therapy (BNCT) are currently taking place in the USA, Europe and Japan. New BNCT clinical facilities are under construction in Finland, Sweden, England and California. The observation of transient acute effects in the oral mucosa of a number of glioma patients involved in the American clinical trials, suggests that radiation damage of the oral mucosa could be a potential complication in future BNCT clinical protocols, involving higher doses and larger irradiation field sizes. The present investigation is the first to use a high resolution surface analytical technique to relate the microdistribution of boron-10 (10B) in the oral mucosa to the biological effectiveness of the 10B(n,α)7Li neutron capture reaction in this tissue. The two boron delivery agents used clinically in Europe/Japan and the USA, borocaptate sodium (BSH) and p-boronophenylalanine (BPA), respectively, were evaluated using a rat ventral tongue model. 10B concentrations in various regions of the tongue mucosa were estimated using ion microscopy. In the epithelium, levels of 10B were appreciably lower after the administration of BSH than was the case after BPA. The epithelium:blood 10B partition ratios were 0.2:1 and 1:1 for BSH and BPA respectively. The 10B content of the lamina propria was higher than that measured in the epithelium for both BSH and BPA. The difference was most marked for BSH, where 10B levels were a factor of six higher in the lamina propria than in the epithelium. The concentration of 10B was also measured in blood vessel walls where relatively low levels of accumulation of BSH, as compared with BPA, was demonstrated in blood vessel endothelial cells and muscle. Vessel wall:blood 10B partition ratios were 0.3:1 and 0.9:1 for BSH and BPA respectively. Evaluation of tongue mucosal response (ulceration) to BNC irradiation indicated a considerably reduced radiation sensitivity using BSH as the boron delivery agent relative to BPA. The compound biological effectiveness (CBE) factor for BSH was estimated at 0.29 ± 0.02. This compares with a previously published CBE factor for BPA of 4.87 ± 0.16. It was concluded that variations in the microdistribution profile of 10B, using the two boron delivery agents, had a significant effect on the response of oral mucosa to BNC irradiation. From a clinical perspective, based on the findings of the present study, it is probable that potential radiation-induced oral mucositis will be restricted to BNCT protocols involving BPA. However, a thorough high resolution analysis of 10B microdistribution in human oral mucosal tissue, using a technique such as ion microscopy, is a prerequisite for the use of experimentally derived CBE factors in clinical BNCT. © 2000 Cancer Research Campaig

    A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles

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    Numerous luminophores may be encapsulated into silica nanoparticles (< 100 nm) using the reverse microemulsion process. Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring. Such nanospheres represent attractive nanoplatforms for the development of biotargeted biocompatible luminescent tracers. Physical and chemical properties of the encapsulated molecules may be affected by the nanomatrix. This study examines the synthesis of different types of dispersed silica nanoparticles, the ability of the selected luminophores towards incorporation into the silica matrix of those nanoobjects as well as the photophysical properties of the produced dye-doped silica nanoparticles. The nanoparticles present mean diameters between 40 and 60 nm as shown by TEM analysis. Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles. This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles

    Zinc Phthalocyanine−Graphene Hybrid Material for Energy Conversion: Synthesis, Characterization, Photophysics and Photoelectrochemical Cell Preparation

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    Graphene exfoliation upon tip sonication in o-­‐DCB was accomplished. Then, covalent grafting of (2-­‐ aminoethoxy)(tri-­‐tert-­‐butyl) zinc phthalocyanine (ZnPc), to exfoliated graphene sheets was achieved. The newly formed ZnPc-­‐graphene hybrid material was found soluble in common organic solvents without any precipitation for several weeks. Application of diverse spectroscopic techniques verified the successful formation of ZnPc-­‐graphene hybrid materi-­‐ al, while thermogravimetric analysis revealed the amount of ZnPc loading onto graphene. Microscopy analysis based on AFM and TEM was applied to probe the morphological characteristics and to investigate the exfoliation of graphene sheets. Efficient fluorescence quenching of ZnPc in the ZnPc-­‐graphene hybrid material suggested that photoinduced events occur from the photoexcited ZnPc to exfoliated graphene. The dynamics of the photoinduced electron transfer was evaluated by femtosecond transient absorption spectroscopy, thus, revealing the formation of transient species such as ZnPc+ yielding the charge-­‐separated state ZnPc•+–graphene•–. Finally, the ZnPc-­‐graphene hybrid material was integrated into a photoactive electrode of an optical transparent electrode (OTE) cast with nanostructured SnO2 films (OTE/SnO2), which exhibited sta le and reproducible photocurrent responses and the incident photon-­‐to-­‐current conversion efficien-­‐ cy was determine

    GSK-3β Is Required for Memory Reconsolidation in Adult Brain

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    Activation of GSK-3β is presumed to be involved in various neurodegenerative diseases, including Alzheimer's disease (AD), which is characterized by memory disturbances during early stages of the disease. The normal function of GSK-3β in adult brain is not well understood. Here, we analyzed the ability of heterozygote GSK-3β knockout (GSK+/−) mice to form memories. In the Morris water maze (MWM), learning and memory performance of GSK+/− mice was no different from that of wild-type (WT) mice for the first 3 days of training. With continued learning on subsequent days, however, retrograde amnesia was induced in GSK+/− mice, suggesting that GSK+/− mice might be impaired in their ability to form long-term memories. In contextual fear conditioning (CFC), context memory was normally consolidated in GSK+/− mice, but once the original memory was reactivated, they showed reduced freezing, suggesting that GSK+/− mice had impaired memory reconsolidation. Biochemical analysis showed that GSK-3β was activated after memory reactivation in WT mice. Intraperitoneal injection of a GSK-3 inhibitor before memory reactivation impaired memory reconsolidation in WT mice. These results suggest that memory reconsolidation requires activation of GSK-3β in the adult brain
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