Production and characterization of lipase from Bacillus stearothermophilus

The production of lipase by Bacillus stearothermophilus was investigated and its properties were evaluated. Different factors such as temperature, pH, carbon source, incubation period and culture volume were studied for improving lipase production. B. stearothermophilus was able to produce lipase at a wide range of temperature and pH values. The maximum enzyme activity of 90.569±0.068 U/ml was recorded when the microorganism was grown in a medium containing olive oil as a carbon source and supplied with Tween 80 at a temperature of 45°C and a pH of 8.0 for 24 h of fermentation. The enzyme showed good stability and tolerance for various parameters studied, with residual activity above 50% over a wide range of temperatures. Lipase was stable at pH 8.0 showing 99.64% of residual activity while it lost its stability almost completely at pH 6.0 and 10.0. The enzyme exhibited a moderate stability in organic solvents and seemed to be activated by isopropanol at a concentration of 25 and 100%. The enzyme retained more than 94% of its activity in a buffer system supplied with EDTA and retained over 80% of its activity in a buffer system supplied with Zn2+ compared to the metal ions investigated. These results show a great potential for the use of this enzyme in industry and other future studies.Key words: Lipase, Bacillus stearothermophilus, optimization, enzyme characterization

Long-term stability studies of a semiconductor photoelectrode in three-electrode configuration

Improving the stability of semiconductor materials is one of the major challenges for sustainable and economic photoelectrochemical water splitting. N-terminated GaN nanostructures have emerged as a practical protective layer for conventional high efficiency but unstable Si and III-V photoelectrodes due to their near-perfect conduction band-alignment, which enables efficient extraction of photo-generated electrons, and N-terminated surfaces, which protects against chemical and photo-corrosion. Here, we demonstrate that Pt-decorated GaN nanostructures on an n+-p Si photocathode can exhibit an ultrahigh stability of 3000 h (i.e., over 500 days for usable sunlight ∼5.5 h per day) at a large photocurrent density (>35 mA cm-2) in three-electrode configuration under AM 1.5G one-sun illumination. The measured applied bias photon-to-current efficiency of 11.9%, with an excellent onset potential of ∼0.56 V vs. RHE, is one of the highest values reported for a Si photocathode under AM 1.5G one-sun illumination. This study provides a paradigm shift for the design and development of semiconductor photoelectrodes for PEC water splitting: stability is no longer limited by the light absorber, but rather by co-catalyst particles

Neuropsychological Assessment of Children With Reading Disabilities From 8 to 10 Years Old: An Exploratory Portuguese Study

Abstract Reading disabilities are one of the most significant causes of school failure and may result from different causes and cognitive processes. A comprehensive battery of neuropsychological tests was applied to a control group of 102 children (46 girls, 56 boys) with no history of learning disabilities and 32 children (13 girls, 19 boys) with poor reading achievement (PRA) to characterize their cognitive profile. A principal component analysis of the cognitive measures was undertaken to identify cognitive domains. Age-adjusted normative data were computed from controls for verbal and visuospatial abilities, psychomotor skills, executive functions, and a total score. Significant differences were found between the 2 groups. Although single tests could not identify children with PRA, measures of oral and written language, immediate and working memory, calculation, and verbal learning discriminated the 2 groups. A logistic regression model using these factors allowed us to identify 91.2% of healthy children and 96.9% of children with PRA. PRA may result from different patterns of cognitive difficulties, and it is more common in children with oral language and working-memory deficits. Wide-range cognitive testing is necessary to identify strong and weak areas to plan personalized intervention program

Non-intersecting leaf insertion algorithm for tree structure models

We present an algorithm and an implementation to insert broadleaves or needleleaves to a quantitative structure model according to an arbitrary distribution, and a data structure to store the required information efficiently. A structure model contains the geometry and branching structure of a tree. The purpose of the work is to offer a tool for making more realistic simulations with tree models with leaves, particularly for tree models developed from terrestrial laser scan (TLS) measurements. We demonstrate leaf insertion using cylinder-based structure models, but the associated software implementation is written in a way that enables the easy use of other types of structure models. Distributions controlling leaf location, size and angles as well as the shape of individual leaves are user-definable, allowing any type of distribution. The leaf generation process consist of two stages, the first of which generates individual leaf geometry following the input distributions, while in the other stage intersections are prevented by doing transformations when required. Initial testing was carried out on English oak trees to demonstrate the approach and to assess the required computational resources. Depending on the size and complexity of the tree, leaf generation takes between 6 and 18 minutes. Various leaf area density distributions were defined, and the resulting leaf covers were compared to manual leaf harvesting measurements. The results are not conclusive, but they show great potential for the method. In the future, if our method is demonstrated to work well for TLS data from multiple tree types, the approach is likely to be very useful for 3D structure and radiative transfer simulation applications, including remote sensing, ecology and forestry, among others

Histological changes and impairment of liver mitochondrial bioenergetics after long-term treatment with alpha-naphthyl-isothiocyanate (ANIT)

This study was designed to evaluate the effects of long-term treatment with alpha-naphthyl-isothiocyanate (ANIT) on liver histology and at the mitochondrial bioenergetic level. Since, ANIT has been used as a cholestatic agent and it has been pointed out that an impairment of mitochondrial function is a cause of hepatocyte dysfunction leading to cholestatic liver injury, serum markers of liver injury were measured and liver sections were analyzed in ANIT-treated rats (i.p. 80 mg/kg/week x 16 weeks). Mitochondrial parameters such as transmembrane potential, respiration, calcium capacity, alterations in permeability transition susceptibility and ATPase activity were monitored. Histologically, the most important features were the marked ductular proliferation, proliferation of mast cells and the presence of iron deposits in ANIT-treated liver. Mitochondria isolated from ANIT-treated rats showed no alterations in state 4 respiration, respiratory control ratio and ADP/O ratio, while state 3 respiration was significantly decreased. No changes were observed on transmembrane potential, but the repolarization rate was decreased in treated rats. Consistently with these data, there was a significant decrease in the ATPase activity of treated mitochondria. Associated with these parameters, mitochondria from treated animals exhibited increased susceptibility to mitochondrial permeability transition pore opening (lower calcium capacity). Since, human cholestatic liver disease progress slowly overtime, these data provide further insight into the role of mitochondrial dysfunction in the process

Physio-chemical assessment of beauty leaf (Calophyllum inophyllum) as second-generation biodiesel feedstock

Recently, biodiesels from non-edible vegetable oil, known as second generation biodiesel, are receiving more attention because it can overcome food versus fuel crisis related to edible oils. The Beauty Leaf tree (Calophyllum Inophyllum) is a potential source of non-edible vegetable oil for producing future generation biodiesel because of its sustainability in a wide range of climate conditions, easy cultivation, high fruit production rate, and the high oil content in the seed. In this study, bio-oil was extracted from beauty leaf tree seeds through three different oil extraction methods. The important physical and chemical properties of produced beauty leaf oils were experimentally analysed and compared with commercial edible vegetable oils. Biodiesel was produced using a two-stage esterification process consisting of acid catalysed pre-esterification and alkali catalysed Transesterification. Fatty acid methyl ester (FAME) profile and physicochemical properties including kinematic viscosity, density, higher heating value and acid value were measured using laboratory standard testing equipment following internationally recognized testing procedures. Other fuel properties including oxidation stability, iodine value, cetane number, flash point, cold filter plugging point, cloud point and pour point temperature were estimated using Fatty acid methyl ester (FAME) of biodiesel. Physicochemical properties of beauty leaf oil biodiesels are described briefly and compared with recognised biodiesel standards and commercially available biodiesels produced from edible oil feedstock. Quality of produced biodiesel was assessed based 13 important chemical and physical properties through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. This study found that Mechanical extraction using the screw press can produce oil from correctly prepared product at a low cost, however overall this method is ineffective with relatively low oil yields. The study found that seed preparation has a significant impact on oil yields, especially in the mechanical oil extraction method. High temperature and pressure in extraction process increases the performance of oil extraction. On the contrary, this process increases the free fatty acid content in the oil. Clear difference was found in physical properties of beauty leaf oils that eventually affected the oil to biodiesel conversion process. However, beauty leaf oils methyl esters (biodiesel) were very consistent and able to meet almost all indicators of biodiesel standards. Furthermore, it showed as a better automobile fuel compared to most of the commercially available biodiesels produced from edible oil sources. Result of this study indicated that, Beauty Leaf oil seed is readily available feedstock to commence the commercial production of 2nd generation biodiesel. The findings of this study are expected to serve as the basis from which industrial scale biodiesel production from Beauty Leaf can be made

Study protocol of cost-effectiveness and cost-utility of a biopsychosocial multidisciplinary intervention in the evolution of non-specific sub-acute low back pain in the working population: cluster randomised trial.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain (LBP), with high incidence and prevalence rate, is one of the most common reasons to consult the health system and is responsible for a significant amount of sick leave, leading to high health and social costs. The objective of the study is to assess the cost-effectiveness and cost-utility analysis of a multidisciplinary biopsychosocial educational group intervention (MBEGI) of non-specific sub-acute LBP in comparison with the usual care in the working population recruited in primary healthcare centres. Methods/design: The study design is a cost-effectiveness and cost-utility analysis of a MBEGI in comparison with the usual care of non-specific sub-acute LBP.Measures on effectiveness and costs of both interventions will be obtained from a cluster randomised controlled clinical trial carried out in 38 Catalan primary health care centres, enrolling 932 patients between 18 and 65 years old with a diagnosis of non-specific sub-acute LBP. Effectiveness measures are: pharmaceutical treatments, work sick leave (% and duration in days), Roland Morris disability, McGill pain intensity, Fear Avoidance Beliefs (FAB) and Golberg Questionnaires. Utility measures will be calculated from the SF-12. The analysis will be performed from a social perspective. The temporal horizon is at 3 months (change to chronic LBP) and 12 months (evaluate the outcomes at long term. Assessment of outcomes will be blinded and will follow the intention-to-treat principle. Discussion: We hope to demonstrate the cost-effectiveness and cost-utility of MBEGI, see an improvement in the patients' quality of life, achieve a reduction in the duration of episodes and the chronicity of non-specific low back pain, and be able to report a decrease in the social costs. If the intervention is cost-effectiveness and cost-utility, it could be applied to Primary Health Care Centres. Trial registration: ISRCTN: ISRCTN5871969

Hyperhomocysteinemia and Low Folate and Vitamin B12 Are Associated with Vascular Dysfunction and Impaired Nitric Oxide Sensitivity in Morbidly Obese Patients.

There is a high prevalence of hyperhomocysteinemia that has been linked to high cardiovascular risk in obese individuals and could be attributed to poor nutritional status of folate and vitamin B12. We sought to examine the association between blood homocysteine (Hcy) folate, and vitamin B12 levels and vascular dysfunction in morbidly obese adults using novel ex vivo flow-induced dilation (FID) measurements of isolated adipose tissue arterioles. Brachial artery flow-mediated dilation (FMD) was also measured. Subcutaneous and visceral adipose tissue biopsies were obtained from morbidly obese individuals and non-obese controls. Resistance arterioles were isolated in which FID, acetylcholine-induced dilation (AChID), and nitric oxide (NO) production were measured in the absence or presence of the NO synthase inhibitor, L-NAME, Hcy, or the superoxide dismutase mimetic, TEMPOL. Our results demonstrated that plasma Hcy concentrations were significantly higher, while folate, vitamin B12, and NO were significantly lower in obese subjects compared to controls. Hcy concentrations correlated positively with BMI, fat %, and insulin levels but not with folate or vitamin B12. Brachial and arteriolar vasodilation were lower in obese subjects, positively correlated with folate and vitamin B12, and inversely correlated with Hcy. Arteriolar NO measurements and sensitivity to L-NAME were lower in obese subjects compared to controls. Finally, Hcy incubation reduced arteriolar FID and NO sensitivity, an effect that was abolished by TEMPOL. In conclusion, these data suggest that high concentrations of plasma Hcy and low concentrations of folate and vitamin B12 could be independent predictors of vascular dysfunction in morbidly obese individuals