GaAs-MISFETs with insulating gate films formed by direct oxidation and by oxinitridation of recessed GaAs surfaces

Direct oxidation by an ultraviolet (UV) and ozone process and oxinitridation (plasma nitridation after oxidation) of GaAs surfaces were used to form nanometer-scale gate insulating layers for depletion-type recessed gate GaAs-MISFETs. The drain current-drain voltage characteristics of the oxide gate devices exhibit lower transconductance (max. 40 mS/mm), lower breakdown voltage and smaller gate capacitance than the oxinitrided gate devices. The presence of hysteresis in the oxide gate devices is also apparent. The maximum transconductance of the oxinitrided gate devices is 110 mS/mm and they have a sharper pinch-off, compared to the oxide gate devices. In addition, no hysteresis is observed in their current voltage curves. The current gain cutoff frequency of 1.4 /spl mu/m gate-length FETs for both types is 6 GHz. These results correspond well with results obtained from characterization of these insulating films.     

Age-related changes in the metabolism of acetylated low-density lipoproteins by peritoneal macrophages from C57BL/6CrScl mice

Macrophages are major precursors of foam cells in atherosclerotic lesions. Acetylated low-density lipoproteins (acetyl LDL) taken up by macrophages through scavenger receptors are degraded by lysosomes and the released cholesterol is re-esterified, leading to foam cell formation. The ability of resident peritoneal macrophages from C57BL/6CrScl mice to form foam cells in relation to the donor age was assessed by the cholesterol esterification and the metabolism of acetyl LDL. The incorporation of 14C-oleate (complexed to albumin) into cellular cholesteryl esters in the presence of acetyl LDL (100 micrograms/ml) was significantly greater in macrophages from senescent mice (24-25 months) than in cells from young (3-4 months) mice (p < .001). The degradation and cellular association of acetyl LDL by macrophages from senescent mice were significantly greater than macrophages from mature mice, (p < .001 and p < .01, respectively), whereas the binding of acetyl LDL was similar in peritoneal macrophages from mature and senescent mice. These results suggest that the uptake and degradation of acetyl LDL, and the re-esterification by macrophages increase with advancing age and that the ability of macrophages to form foam cells increases with aging. The enhanced ability of senescent macrophages to form foam cells might contribute to the development and progression of atherosclerosis related to the aging process.     

Effect of fatty oil dispersion on oil-containing wastewater treatment

The performance of an immobilized continuous fluidized reactor for salad oil-containing model wastewater was examined at a high loading rate using polyurethane as a support, to be applied in fat- and oil-containing wastewater treatment, generated by daily activities in restaurant kitchens. At an organic loading rate higher than 0.6 kg/m3/day, there was a significant amount of white solid (WS), identified as a mixture of calcium di-stearate and di-palmitate, suggesting that saturated fatty acid degradation was limited at such a high loading rate, possibly due to its solubility in the wastewater. Increased oil dispersion by the addition of a surfactant ranging from 10 to 100 microm particle size could result in less than 30 mg/l oil concentration after the treatment at 5 kg/m3/day.     

Immunohistochemical studies of proliferating cell nuclear antigen and cathepsin D in transitional cell carcinoma of the urinary bladder

Immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and cathepsin D was performed on 60 transitional cell carcinoma (TCC) specimens from 60 patients with bladder cancer. The percentage of PCNA-positive cells (PCNA-labelling index) was determined by counting 500 or 1,000 cells, and cathepsin D expression was graded according to the extent of immunoreactivity to anti-cathepsin D antibody. The PCNA-labelling index was significantly higher in high-grade and high-stage tumors compared to that in low-grade and low-stage tumors. Cathepsin D was highly positive in grade-1 tumors. In contrast, 82% of grade-3 tumors and 76% of advanced tumors showed negative or low reactivity to anti-cathepsin D. Groups of high PCNA-labelling index and negative cathepsin D had significantly poorer prognoses compared to those of the low PCNA group and cathepsin D highly positive group, respectively, in univariate analyses. However, neither of these two factors were independent prognostic factors in multivariate analyses. These results suggest that the PCNA-labelling index and cathepsin D expression may indicate the malignant potential of TCC and may be able to provide additional information for predicting survival when stratifying for grade of bladder cancer.     

Links between energy access and food security in sub Saharan Africa: an exploratory review

Three quarters of the population in Sub Saharan Africa lacks access to modern energy, and relies instead on biomass fuels for cooking and heating. The environment and health implications of the use of biomass fuel has been widely documented in the literature, and has raised the topic of energy access in various policy and development arenas. Still, the impact of energy access on food security at the household level has not been explored in detail; consequently the two sectoral policies remain unaligned. Our aims for this review were to document how lack of access to energy can impact on food security through influence on dietary choices and cooking practices; and how reallocation of household resources from food to energy procurement causes a switch to biomass energy forms of lower grade. We searched the literature for published peer-reviewed articles available through major online publication databases, initially identifying 132 articles but finally reviewing a set of 19 that met our criteria. While most studies suggested that fuelwood scarcity can affect food security through three hypothesised pathways, very few of them provided empirical data to support this argument. Overall, the review found coping measures for woodfuel scarcity to be highly contextual and influenced by geography, household economy and labour availability. Due to the limited number of studies with detailed data, it was not possible to perform a comparative analysis that could support or refute a hypothesis that lack of access to energy can impact on food security. More rigorous studies on this topic are needed which could provide evidence for policy action.     

Determination of lignin in herbaceous plants by an improved acetyl bromide procedure

A modified acetyl bromide procedure is proposed for the spectrophotometric determination of lignin in herbaceous plants. The digestion with 25 % acetyl bromide (AcBr) in acetic acid at 70°C is improved by including 4 % perchloric acid in the digesting solutions. This allows for more rapid, complete digestion and the use of coarser samples. On the basis of infrared spectra and nitrobenzene oxidation data for milled sample lignins, the value of 20.0 g^?1 litre cm^?1 for the specific absorption coeficient of AcBr-treated lignins of herbaceous plant samples gave lignin values which were consistent with nitrobenzene oxidation data, but were higher than those obtained by the acid detergent lignin method and the earlier AcBr method proposed for grasses. The lower lignin values obtained in the latter methods are considered to be due to partial lignin solubilisation in the sulphuric acid digestion.     

Frequency domain detection of coherence multiplexed sensor signalsby using an optical loop with a frequency shifter

We describe a frequency domain detection scheme of coherence multiplexed sensor signals by using an optical loop with a frequency shifter. The optical path differences of the sensors are adjusted to integer-multiple of the loop length of the optical loop, and then the the sensor signals are multiplexed in the frequency domain, appearing at the integer-multiple of the working frequency of the frequency shifter. In the experiment, four Michelson-type sensors are successfully multiplexed with the sensitivities of about 2 mrad/√Hz. The sensitivities are also theoretically calculated which are in good agreement with the experimental results. The optimum design of the optical loop is also discussed     

Overexpression of c-met proto-oncogene associated with chromophilic renal cell carcinoma with papillary growth

The in vitro antiviral activity against picornaviruses (rhinovirus serotype 1B and 14, and poliovirus type 2) of new synthetic 3-hydroxyflavones, 3-acetoxyflavones, and substituted cinnamic and benzoic acid flavon-3-yl esters was evaluated. The maximum non-toxic concentration of compounds was determined in a human cell line (HeLa) suitable for the replication of the three viruses. Their antiviral potency was measured by a plaque reduction assay. Generally, rhinoviruses exhibited a higher sensitivity to the new flavonoids than poliovirus. Flavones, with sterically small substituents in position 3, showed good activity against both rhinoviruses tested. However, the introduction of bulky substituents in the same position resulted in analogues with a higher toxicity and often with a lower efficacy.