Chemical Profile and Biological Activities of Two Edible Plants: Chemical Investigation and Quantitative Analysis Using Liquid Chromatography Tandem Mass Spectrometry and Gas Chromatography Mass Spectrometry

The objectives of this study were to define the phenolic and fatty acid profiles, anticholinesterase, antioxidant, antimicrobial activities, and total phenolic-flavonoid contents of Lycopsis orientalis and Tragopogon latifolius var. angustifolius which have been used as food source and food supplement in Anatolia and have never been examined before. Rosmarinic and quinic acids (21.11 and 11.46 mg g^–1 extract, respectively) were found to be the most abundant constituents in L. orientalis and T. latifolius var. angustifolius among the studied 27 compounds by liquid chromatography tandem mass spectrometry. In the fatty acid compositions of L. orientalis and T. latifolius var. angustifolius that were determined by gas chromatography mass spectrometry, oleic (29.1%) and palmitic (28.7%) acids were identified as the major components, respectively. The high antioxidant activity of the methanol extract of L. orientalis shows parallelism to its rosmarinic acid content. Besides, this extract showed medium anticholinesterase activity. The results of the present study proves that the L. orientalis might also be used as a food source due to its high phenolic acid content and strong antioxidant property.     

Distribution of lengths in the breakage of fibres or linear polymers

The distribution of fiber or polymer lengths during breakage is considered. It is shown that under certain conditions the distribution of lengths is given by a self-preserving form which is independent of the initial distribution and is not explicitly dependent on time. Some self-preserving distributions are calculated. The theory is compared with an experiment on the breakage of glass fibres caused by milling.     

Weak Convex Decomposition by Lines‐of‐sight

We define the convexity rank of a set of points to be the portion of mutually visible pairs of points out of the total number of pairs. Based on this definition of weak convexity, we introduce a spectral method that decomposes a given shape into weakly convex regions. The decomposition is applied without explicitly measuring the convexity rank. The method merely amounts to a spectral clustering of a matrix representing the all‐pairs line of sight. Our method can be directly applied on an oriented point cloud and does not require any topological information, nor explicit concavity or convexity measures. We demonstrate the efficiency of our algorithm on a large number of examples and compare them qualitatively with competitive approaches.     

Dye–fibre bond stabilities of some reactive dyes on cotton

Cotton fabric dyed with commercial reactive dyes of the monochloro-s-triazine, bis(monochloro-s-triazine), and bis(monofluoro-s-triazine) type was treated in buffer solutions pH 10 and 12 at 60, 85 and 98°C. Hydrolysis has been investigated using spectrophotometrical measurements of hydrolysed dye at λ_max. The percent of hydrolysed dye was calculated.     

Changing prevalence of asthma among schoolchildren in Israel

This survey was part of a health monitoring system operated in the vicinity of a new power plant in Israel. The aim of this analysis was to determine whether a temporal trend of increased prevalence of asthma can be observed among cohorts of same-aged children, between 1980 and 1989. Schoolchildren were followed up between 1980 and 1989. They performed pulmonary function tests (PFTs), and their parents filled out American Thoracic Society-National Heart and Lung Institute (ATS-NHLI) health questionnaires. This report deals with the changes in the prevalence of asthma, related respiratory conditions and PFT in four cross-sectional data sets gathered among eighth-grade schoolchildren (aged 13-14 yrs). A highly significant (p=0.0005) increase in the prevalence of asthma (from 5.6% in 1980 to 11.2% in 1989), and of wheezing accompanied by shortness of breath (p=0.0009) could be observed. A similar trend could not be found for the prevalence of bronchitis among these children. PFTs of children suffering from asthma or from wheeze accompanied by shortness of breath were lower than those of healthy children. Changes in prevalence of background variables over time could not explain these findings. The significant rise in the prevalence of asthma coupled with reduced pulmonary function test results among asthmatic children, seems to reflect a true increase in morbidity. Temporal changes in the prevalence of background variables as well as proximity to the power plant could not explain this trend.     

Fullerene photoelectrochemical solar cells

The photoelectrochemistry of single crystal C₆₀ and fullerene photoelectrochemical solar cells is studied. Illuminated and immersed, C₆₀ is shown to drive oxidation of several solution-phase redox couples. Utilization of a photoelectrochemical solid/liquid junction, rather than solid-state photovoltaic junction, improves the observed photocurrent. Utilization of a single crystal, rather than a polycrystalline film, of C₆₀ decreases dark current to the extent that light-driven charge transfer dominates. The spectral response and current-voltage behaviour in several electrolytes is studied. A low-power fullerene photoelectrochemical solar cell, utilizing a regenerative polyiodide and ferri/ferrocyanide redox couple, is demonstrated.     

Photoaction, temperature and O2 depletion effects in fullerene photoelectrochemical solar cells

It is demonstrated that higher temperature and C₆₀ oxygen depletion increase the photocurrent of fullerene photoelectrochemical solar cells (PEC). Fullerene/iodide electrolyte PEC consisting of intrinsic single crystal C₆₀ in either aqueous 3 M KI, 0.01 M I₂, or 0.1 M tetrabutyl ammonium iodide, 0.3 M LiClO₄ in acetonitrile solution, drive regenerative photoinduced iodide oxidation. The photocurrent is increased by an order of magnitude (to 6.4 μA/cm² under 100 mW/cm² illumination) by an increase of the aqueous cell temperature from 24°C to 82°C. A similar order of magnitude increase in photocurrent is accomplished by O₂ depletion pretreatment (24 h at 400°C in Ar) of the C₆₀ to improve conductivity. However, this latter treatment also irreversibly increases the cell dark current. The spectral action of single crystal C₆₀ is also probed, through the generated photoelectrochemical current in iodide, ferricyanide and sulfuric electrolytes as a function of wavelength. Band edges are observed at 720 nm (1.7 eV) and 560 nm (2.2 eV), and a substantial peak photocurrent response occurs at 395 nm (3.1 eV) and decreases at shorter wavelengths.     

A Photovoltaic C60-Si Heterojunction

A heterojunction was prepared by depositing a thin film of C₆₀ on a p-Si substrate. Photovoltaic properties were observed using a UV-filtered solar simulator and natural sun light. Surface Photovoltage Spectroscopy was employed to distinguish between the nature of photoconversion in the C₆₀ and Si layers.