1,548 research outputs found

    Effects of n-butanol and filipin on membrane permeability of developing wheat endosperm with different sterol phenotypes.

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    Sterols are considered structural components of higher plant membranes on the basis of their presence in membrane-containing subcellular fractions [1—3], their effect on plant membrane permeability when added exogenously [4,5] and the sensitivity of plant cells to the polyene antibiotic filipin [6—8], which action is known to depend on the presence of sterols in the membrane (see [8]). Our recent finding of a gene that controls the free sterol level of developing wheat endosperm [9—11 ] allows to investĂ­gate whether endogenous sterol modifies membrane permeability in the same way as that added externally. We report here on the effect of «-butanol and filipin on the leakage properties of developing wheat endosperms with different genetically determined free sterol levĂ©is

    Chromosomal location of a gene that controls sterol esterification in Triticum aestivum L.

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    A previously described D genome locus (Pln) that controls sterol esterification in the wheat kernel has been assigned to the short arm of chromosome 7 D by comparison of the steryl ester phenotype of euploid kernels of Triticum aestivum variety Chinese Spring with those of the compensated nulli-tetrasomic lines and the 7 D S ditelosomic. Palmitate is the predominant ester in all but the 7 D nullisomic combinations, which have linoleate as the main ester. These lines also show a marked decrease in sterol esterification and a two-fold increase in free sterol, indicating that chromosomes 7 A and 7 B do not compensate for the loss of esterification capacity associated with 7 D

    Pathological regional blood flow in opiate-dependent patients during withdrawal: A HMPAO-SPECT study

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    The aims of the present study were to investigate regional cerebral blood flow (rCBF) in heroin-dependent patients during withdrawal and to assess the relation between these changes and duration of heroin consumption and withdrawal data. The rCBF was measured using brain SPECT with Tc-99m-HMPAO in 16 heroin-dependent patients during heroin withdrawal. Thirteen patients received levomethadone at the time of the SPECT scans. The images were analyzed both visually and quantitatively, a total of 21 hypoperfused brain regions were observed in 11 of the 16 patients. The temporal lobes were the most affected area, hypoperfusions of the right and left temporal lobe were observed in 5 and 5 patients, respectively. Three of the patients had a hypoperfusion of the right frontal lobe, 2 patients showed perfusion defects in the left frontal lobe, right parietal lobe and left parietal lobe. The results of the quantitative assessments of the rCBF were consistent with the results of the qualitative findings. The stepwise regression analysis showed a significant positive correlation (r = 0.54) between the dose of levomethadone at the time of the SPECT scan and the rCBF of the right parietal lobe. Other significant correlations between clinical data and rCBF were not found. The present results suggest brain perfusion abnormalities during heroin withdrawal in heroin-dependent patients, which are not due to the conditions of withdrawal

    Prediction of soil physical and chemical properties by visible and near-infrared diffuse reflectance spectroscopy in the Central Amazon.

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    Visible and near-infrared diffuse reflectance spectroscopy (VIS-NIR) has shown levels of accuracy comparable to conventional laboratory methods for estimating soil properties. Soil chemical and physical properties have been predicted by reflectance spectroscopy successfully on subtropical and temperate soils, whereas soils from tropical agro-forest regions have received less attention, especially those from tropical rainforests. A spectral characterization provides a proficient pathway for soil characterization. The first step in this process is to develop a comprehensive VIS-NIR soil library of multiple key soil properties to be used in future soil surveys. This paper presents the first VIS-NIR soil library for a remote region in the Central Amazon. We evaluated the performance of VIS-NIR for the prediction of soil properties in the Central Amazon, Brazil. Soil properties measured and predicted were: pH, Ca, Mg, Al, H, H+Al, P, organic C (SOC), sum of bases, cation exchange capacity (CEC), percentage of base saturation (V), Al saturation (m), clay, sand, silt, silt/clay (S/C), and degree of flocculation. Soil samples were scanned in the laboratory in the VIS-NIR range (350-2500 nm), and forty-one pre-processing methods were tested to improve predictions. Clay content was predicted with the highest accuracy, followed by SOC. Sand, S/C, H, Al, H+Al, CEC, m and V predictions were reasonably good. The other soil properties were poorly predicted. Among the soil properties predicted well, SOC is one of the critical soil indicators in the global carbon cycle. Besides the soil property of interest, the landscape position, soil order and depth influenced in the model performance. For silt content, pH and S/C, the model performed better in well-drained soils, whereas for SOC best predictions were obtained in poorly drained soils. The association of VIS-NIR spectral data to landforms, vegetation classes, and soil types demonstrate potential for soil characterization

    Photo‐biocatalytic Cascades:Combining Chemical and Enzymatic Transformations Fueled by Light

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    In the field of green chemistry, light – an attractive natural agent – has received particular attention for driving biocatalytic reactions. Moreover, the implementation of light to drive (chemo)enzymatic cascade reactions opens up a golden window of opportunities. However, there are limitations to many current examples, mostly associated with incompatibility between the enzyme and the photocatalyst. Additionally, the formation of reactive radicals upon illumination and the loss of catalytic activities in the presence of required additives are common observations. As outlined in this review, the main question is how to overcome current challenges to the exploitation of light to drive (chemo)enzymatic transformations. First, we highlight general concepts in photo-biocatalysis, then give various examples of photo-chemoenzymatic (PCE) cascades, further summarize current synthetic examples of PCE cascades and discuss strategies to address the limitations

    Beyond Speculative Robot Ethics

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    In this article we develop a dialogue model for robot technology experts and designated users to discuss visions on the future of robotics in long-term care. Our vision assessment study aims for more distinguished and more informed visions on future robots. Surprisingly, our experiment also lead to some promising co-designed robot concepts in which jointly articulated moral guidelines are embedded. With our model we think to have designed an interesting response on a recent call for a less speculative ethics of technology by encouraging discussions about the quality of positive and negative visions on the future of robotics.

    Modest serum creatinine elevation affects adverse outcome after general surgery

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    Modest serum creatinine elevation affects adverse outcome after general surgery.BackgroundModest preoperative serum creatinine elevation (1.5 to 3.0 mg/dL) has been recently shown to be independently associated with morbidity and mortality after cardiac surgery. It is important to know if this association can be applied more broadly to general surgery cases.MethodsMultivariable logistic regression analyses of 46 risk variables in 49,081 cases from the Veterans Affairs National Surgical Quality Improvement Program, undergoing major general surgery from 10/1/96 through 9/30/98.ResultsThirty day mortality and several cardiac, respiratory, infectious and hemorrhagic morbidities were significantly (P < 0.001) higher in patients with a serum creatinine>1.5 mg/dL. With multivariable analysis, the adjusted odds ratio for mortality for patients with a serum creatinine of 1.5 to 3.0 mg/dL was 1.44 [95% confidence interval (95% CI) 1.22 to 1.71] and for creatinine>3.0 mg/dL was 1.93 (95% CI 1.51 to 2.46). The adjusted odds ratio for morbidity (one or more postoperative complications) for patients with a serum creatinine of 1.5 to 3.0 mg/dL was 1.18 (95% CI 1.06 to 1.32) and for creatinine>3.0 mg/dL was 1.19 (95% CI 0.99 to 1.43). Further stratification and recursive partitioning of creatinine levels revealed that a serum creatinine level>1.5 mg/dL was the approximate threshold for both increased morbidity and mortality.ConclusionsModest preoperative serum creatinine elevation (>1.5 mg/dL) is a significant predictor of risk-adjusted morbidity and mortality after general surgery. A preoperative serum creatinine of 1.5 mg/dL or higher is a readily available marker for potential adverse outcomes after general surgery
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