Assessment of Calotropis natural dye extracts on the efficiency of dye-sensitized solar cells

ArticleThis work presents the construction and testing of solar cells sensitized with natural dyes extracted from plants indigenous to the desert. Calotropis plants are self - sufficient as they grow in very harsh environments, and yet are not consumed by humans or livestock due to their irritating agents to the skin and eyes. The energy generators of these plants are the leaves, which are crushed and processed to produce the dye solution. Also, the Calotropis leaves are covered in a white powder that is thought to aid in mitigating the heat by scattering incident radiation. This powder material is examined and added to the dye as it proved advantageous for the o verall cell efficiency, which reached 0.214% compared with 0.108% for cells with no powder. The produced cells are also compared with ones sensitized by spinach, another common natural sensitizer for dye - sensitized solar cells, and the performance proved t o be significantly better. The fact that Calotropis is a non - food plant is an added advantage to utilizing it as a dye source, along with its intrinsic heat resistance that allows it to survive the harsh desert conditions all year round

Investigation of Parietal Polysaccharides from Retama raetam Roots

This study characterizes the cell wall hemicellulose and pectins polymers of Retama raetam. This species develops a particularly important root system and is adapted to arid areas. The cellulose, hemicelluloses and pectins were extracted. The cellulose remains the major component of the wall (27% for young roots and 80% for  adult roots), hemicelluloses (14.3% for young roots and 3.6%  for adult roots) and pectins (17.3% for young roots and 4.1% for adult roots). The monosaccharidic composition of water soluble extracts determined by gas liquid chromatography (GLC) and completed by infrared (FTIR) spectroscopy of hemicellulosic shows the presence of xylose as a major monosaccharide in the non-cellulose polysaccharides (47.8% for young roots and 59.5% for adult roots). These results indicate the presence of the homogalacturonans and rhamnogalacturonans in pectin. This study constitutes the preliminary data obtained in the biochemical analysis of the parietal compounds of the roots of a species which grows in an arid area in comparison with those of its aerial parts.Keywords: Retama raetam, Roots, Cell Wall, Investigation, Polysaccharides, Monosaccharidi

Isotopic and velocity distributions of Bi produced in charge-pickup reactions of 208Pb at 1 A GeV

Isotopically resolved cross sections and velocity distributions have been measured in charge-pickup reactions of 1 A GeV 208Pb with proton, deuterium and titanium target. The total and partial charge-pickup cross sections in the reactions 208Pb + 1H and 208Pb + 2H are measured to be the same in the limits of the error bars. A weak increase in the total charge-pickup cross section is seen in the reaction of 208Pb with the titanium target. The measured velocity distributions show different contributions - quasi-elastic scattering and Delta-resonance excitation - to the charge-pickup production. Data on total and partial charge-pickup cross sections from these three reactions are compared with other existing data and also with model calculations based on the coupling of different intra-nuclear cascade codes and an evaporation code.Comment: 20 pages, 12 figures, background information on http://www-w2k.gsi.de/kschmidt

Achievement of higher thresholds of clinical responses and lower levels of disease activity is associated with improvements in workplace and household productivity in patients with axial spondyloarthritis

Background: Patients with active axial spondyloarthritis (axSpA) exhibit more absences and lower levels of productivity in the workplace and household than the general population, which can improve upon treatment. Objectives: The objective of this study is to determine the long-term impact of achieving different levels of clinical response or disease activity on workplace and household productivity in patients with axSpA. Design: RAPID-axSpA (NCT01087762) was a 204-week phase III trial evaluating the safety and efficacy of certolizumab pegol (CZP) in adult patients with active axSpA. Methods: The impact of axSpA on workplace and household productivity was evaluated using the validated arthritis-specific Work Productivity Survey. Outcomes included the percentage of patients achieving Assessment of SpondyloArthritis International Society (ASAS) response and Ankylosing Spondylitis Disease Activity Score (ASDAS) thresholds. This post hoc study used a generalised estimating equations model to determine the association between the threshold of clinical response achieved and patient productivity. Results: Of 218 CZP-randomised patients, 65.1% completed week 204. At baseline, 72.0% were employed outside the home. Of the patients who were unemployed, 42.6% were unable to work due to arthritis. Achievement of higher treatment response thresholds, such as clinical remission, was associated with fewer days affected by workplace absenteeism (ASAS-partial remission: 4.0 days, ASAS40: 8.6 days, ASAS20 but not reaching ASAS40 response: 29.4 days, ASAS20 non-response: 69.2 days; ASDAS-inactive disease: 5.0 days, ASDAS-low disease activity: 15.6 days, ASDAS-high disease activity: 32.7 days, ASDAS-very high disease activity: 93.4 days). Similar associations were found for workplace presenteeism, and household absenteeism and presenteeism. Conclusions: Over 4 years, achievement of higher clinical response thresholds and lower levels of disease activity was associated with fewer cumulative days affected by absenteeism or presenteeism, with clinical remission associated with the greatest improvements in productivity. This highlights the importance of targeting these thresholds to limit the burden of axSpA on society and on patients’ daily lives

Evaporation residues produced in spallation of 208Pb by protons at 500A MeV

The production cross sections of fragmentation-evaporation residues in the reaction Pb+p at 500A MeV have been measured using the inverse-kinematics method and the FRS spectrometer (GSI). Fragments were identified in nuclear charge using ionisation chambers. The mass identification was performed event-by-event using the B-rho - TOF - Delta-E technique. Although partially-unresolved ionic charge states induced an ambiguity on the mass of some heavy fragments, production rates could be obtained with a high accuracy by systematically accounting for the polluting ionic charge states. The contribution of multiple reactions in the target was subtracted using a new, partly self-consistent code. The isobaric distributions are found to have a shape very close to the one observed in experiments at higher energy. Kinematic properties of the fragments were also measured. The total and the isotopic cross sections, including charge-pickup cross sections, are in good agreement with previous measurements. The data are discussed in the light of previous spallation measurements, especially on lead at 1 GeV

On the global uniform stability analysis of non-autonomous dynamical systems: A survey

In this survey, we introduce the notion of stability of time varying nonlinear systems. In particular we investigate the notion of global practical exponential stability for non-autonomous systems. The proposed approach for stability analysis is based on the determination of the bounds of perturbations that characterize the asymptotic convergence of the solutions to a closed ball centered at the origin