A study of the postnatal change in trace element levels in rat tissues by thermal neutron activation analysis

In order to obtain information about postnatal changes in trace element levels in rat tissues, the age-dependent variations in the concentrations of 6 elements (Fe, Zn, Co, Se, Rb and Cs) were investigated by thermal neutron activation analysis. Several variation patterns were revealed in their concentrations as a function of postnatal age, depending on the combination of an element and an organ: (1) A steady state without significant variations (Zn and Se in brain, Rb and Cs in liver), (2) accumulation till a steady level is attained in time (Se in liver and kidney, Co in kidney), (3) depletion till a steady level is attained in time (Fe and Co in brain, Zn in liver and kidney, Rb and Cs in kidney), (4) permanent depletion (Rb and Cs in brain), and 95) initial drop followed by gradual increase in concentration levels (Fe in liver and kidney, Co in liver)     

Simultaneous liquid chromatographic determination of 39 polycyclic aromatic hydrocarbons in indoor and outdoor air and application to a survey on indoor air pollution in Fuji, Japan

An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution.     

延边地区65～108岁健康老人头发中锌、铜、铁、锰、镁的含量

用原子吸收光谱法测定延边地区317名65～108岁老人头发中锌、铜、铁、锰、镁含量，观察不同民族、性别、年龄老人这些元素的差异。结果表明：1.朝鲜旗发锌低于汉族，满族发铜低于汉族、朝鲜族，汉族发镁高于朝鲜族、满族，发铁、发锰在汉、朝、满民族之间无区别。2．汉族、朝鲜族男发锌高于女性，汉族女性发铜高于男性，发铁、发锰、发镁在性别之间无区别。3、90岁组朝鲜族发锰、发镁低于65岁、76岁组，朝鲜族发锌、发铜、发铁在65～108岁之间无统计学意义。     

Calibration methods for microdialysis sampling in vivo: muscle and adipose tissue

Calibration methods for microdialysis sampling were studied in the muscle and adipose tissue of rats. Both the delivery method and the no-net-flux method were used to determine the extraction efficiency (EE) of acetaminophen and caffeine in both tissues. There was no concentration dependence of the EE either in vitro or in vivo for either acetaminophen or caffeine. The EEs determined by the delivery and no-net-flux methods were not different. However, the EEs of both caffeine and acetaminophen determined in vitro were significantly higher than those determined in the muscle and adipose. This indicates that mass transfer in the tissue is the rate-determining factor for the EE in vivo. The relative difference between the EE in vitro and the EE in the muscle was smaller than the difference between the EE in vitro and the EE in the adipose. In addition, the EE in the muscle decreased more than the EE in the adipose after the animal was euthanized. This indicated that exchange between the extracellular fluid and plasma is the rate-determining step in mass transport relative to microdialysis sampling. This has a more significant effect on the EE in the muscle than the EE in the adipose. Both the delivery and no-net-flux methods can be used to calibrate microdialysis probes in the muscle and adipose.     

Variability of total flavonoid, polyphenol and tannin contents in some Lythrum salicaria populations

Lythrum salicaria L. can vary in some morphological and phytochemical features according to its habitat. The present study investigates and compares the total flavonoid, polyphenol and tannin composition of twelve populations of L. salicaria collected from different ecological habitats in south-west Hungary. We studied the plant heights and soil moistures of the habitats analyzing the potential correlation between the morphological and environmental factors and chemical compositions. Total flavonoid, polyphenol and tannin contents were determined according to the valid spectroscopic methods of the European Pharmacopoeia. Total flavonoid content was higher in the populations collected during the main blooming period in August than at the beginning of flowering in July. Higher values for total polyphenol and tannin were detected in flowering branch tips in August than in July, and higher ones in leaves and shoots in July than in August. The highest flavonoid content was measured in the leaves, followed by the flowering branches and shoots as opposed to the total polyphenol and tannin contents, which were higher in the flowering branch tips than in the other organs.     

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.     

Enantiomer ratio of MK-0767 in humans and nonclinical species

MK-0767, (+/-)-5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[(4-trifluoromethyl)phenyl]methyl]benzamide, is a thiazolidinedione-containing dual peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist that has been studied as a potential treatment for patients with type 2 diabetes. MK-0767 contains a chiral center at the C-5 position of the thiazolidinedione ring and was being developed as the racemate, due to the rapid interconversion of its enantiomers in biological samples. In the present work the in vitro and in vivo concentration ratios of the (+)-(R) to (-)-(S) enantiomers of MK-0767 were determined in plasma from humans (in vitro only) and nonclinical species used in the toxicological evaluation of rac-MK-0767, namely CD-1 mice, Sprague-Dawley rats, beagle dogs, New Zealand white rabbits, and rhesus monkeys. The R/S ratio was determined by chiral liquid chromatography/tandem mass spectrometry. Species differences were observed in the in vitro and in vivo enantiomeric ratios, as well as differences between in vitro and in vivo in some species. The in vitro R/S ratio was similar in dogs and humans (approximately 1.5-1.7). In rats and monkeys, the ratio was approximately unity, both in vitro and in vivo. In mice, the ratio was higher in vitro (approximately 1) than in vivo (approximately 0.6), while in rabbits it was higher in vivo (approximately 1) than in vitro (approximately 0.5). These results suggested that differential binding of the MK-0767 enantiomers to plasma and tissue proteins and other macromolecules may be affecting the R/S ratio both in vitro and in vivo, since in protein-free systems MK-0767 exists as the racemate.     

Field studies on the photosynthesis of two desert Chilean plants: Prosopis chilensis and Prosopis tamarugo.

Photosynthetic parameters were investigated in relation to light intensity (PAR and UV-B) in two Chilean Prosopis sp., Prosopis chilensis and Prosopis tamarugo in their natural habitats. The objective of this work was to compare the photosynthetic responses and to determine the degree of adaptation of both species to visible- and UV-radiation stress. One of the study sites was Refresco in the Atacama Desert, where P. tamarugo is an endemic plant and P. chilensis was introduced, and the other was Peldehue in the valley of Central Chile where only P. chilensis is present. Due to latitude, light intensity (UV-B and PAR) is higher in Refresco than in Peldehue. The parameters investigated in both species were photosystem II fluorescence, CO(2) assimilation, stomatal conductance, photosynthetic pigment composition, flavonoid absorption patterns and composition of chlorophyll-protein complexes. Fluorescence studies, CO(2) assimilation and stomatal conductance studies demonstrated that photosynthetic activity is more efficient and stable throughout the day in P. tamarugo than in P. chilensis in Refresco. Chlorophyll-protein complexes also seemed to be more stable in P. tamarugo than in P. chilensis. Photosynthetic pigment analyses indicated possible photodamage in P. chilensis trees in Refresco, but not in Peldehue. Such photodamage was absent in P. tamarugo. There was a considerable change in the flavonoid pattern between noon and afternoon hours in both species at both study sites. The physiological implications of these changes indicate that P. tamarugo is more adapted to high solar radiation than P. chilensis.     

Histological study of some Echium vulgare, Pulmonaria officinalis and Symphytum officinale populations

Plants living in different ecological habitats can show significant variability in their histological and phytochemical characters. The main histological features of various populations of three medicinal plants from the Boraginaceae family were studied. Stems, petioles and leaves were investigated by light microscopy in vertical and transverse sections. The outline of the epidermal cells, as well as the shape and cell number of trichomes was studied in leaf surface casts. Differences were measured among the populations of Echium vulgare in the width and height of epidermis cells in the stem, petiole and leaf, as well as in the size of palisade cells in the leaves. Among the populations of Pulmonaria officinalis significant differences were found in the length of trichomes and in the slightly or strongly wavy outline of epidermal radial cell walls. Populations of Symphytum officinale showed variance in the height of epidermal cells in leaves and stems, length of palisade cells and number of intercellular spaces in leaves, and the size of the central cavity in the stem. Boraginaceae bristles were found to be longer in plants in windy/shady habitats as opposed to sunny habitats, both in the leaves and stems ofP. officinalis and S. officinale, which might be connected to varying levels of exposure to wind. Longer epidermal cells were detected in the leaves and stems of both E. vulgare and S. officinale plants living in shady habitats, compared with shorter cells in sunny habitats. Leaf mesophyll cells were shorter in shady habitats as opposed to longer cells in sunny habitats, both in E. vulgare and S. officinale. This combination of histological characters may contribute to the plant's adaptation to various amounts of sunshine. The reported data prove the polymorphism of the studied taxa, as well as their ability to adapt to various ecological circumstances.     

Vibronic interactions and possible electron pairing in the photoinduced excited electronic States in molecular systems: a theoretical study

Electron-phonon interactions in the photoinduced excited electronic states in molecular systems such as phenanthrene-edge-type hydrocarbons are discussed and compared with those in the monoanions and cations. The complete phase patterns difference between the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) (the atomic orbitals between two neighboring carbon atoms combined in phase (out of phase) in the HOMO are combined out of phase (in phase) in the LUMO) are the main reason that the C-C stretching modes around 1500 cm(-1) afford much larger electron-phonon coupling constants in the excited electronic states than in the charged electronic states. The frequencies of the vibrational modes that play an essential role in the electron-phonon interactions for the excited electronic states are similar to those for the monoanions and cations in phenanthrene-edge-type hydrocarbons. Possible electron pairing and Bose-Einstein condensation in the photoinduced excited electronic states as well as those in the monoanions and cations in molecular systems such as phenanthrene-edge-type hydrocarbons are also discussed.     

Weak-to-strong confinement transition of semi-flexible macromolecules in slit and in channel

We compare confinement of stiff macromolecule in channel and in slit. Whereas in the channel a distinct and established transition exists, we elucidate here an ongoing controversy reported from previous experiment and simulation on existence of such transition in the slit. Our extensive molecular simulations in both geometries show only a very weak conformational crossover between moderate and strong confinements in slit in the same range of confinements where the distinct transition in channel is observed. In contrast to situation in channels relatively stable hairpin-like structures are not indicated around this weak transition in the slit. Observed difference from the prediction on behavior in blob regime under moderate confinement is explained by a crossover between dimensionalities in the slit and the extent of ideal conformation statistics to which the stiffer chains are prone. The strong confinement regime of stiff chain in slit characterized here has not been interpreted yet and it differs from the respective saturation-like Odijk regime in the channel.     

氨基苯磺酸和氨基萘磺酸在反相离子对色谱和离子色谱中分离行为的比较

本文考察了氨基苯磺酸和氨基萘磺酸染料中间体在反相离子对色谱和离子色谱中的分离行为，结果表明一些异构体在反相色谱中的保留顺序与离子色谱中的顺序发生颠倒。静电作用力在离子色谱中对保留值的贡献比在反相离子对色谱中对保留值的贡献要大，而疏水作用力在反相离子对色谱中对保留值的贡献却较在离子色谱中对保留值的贡献要大。离子对色谱更有利于有机离子的分离分析。     

Voltammetric determination of platinum in perfusate and blood: Preliminary data on pharmacokinetic study of arterial infusion with oxaliplatin

Because Platinum Group Elements have found widespread use in catalytic converters in cars and as chemotherapeutic agent, interest in the development of reliable analytical methods is carried out in order to monitor these analita in humans to protect the citizen's health.Considering that information on the levels of many trace elements in biological matrices is scarce and for many non-essential elements, baseline levels in the population, and especially in those particularly exposed to the risk are lacking, in this paper we optimize an analytical method for biological matrices, using a voltammetric technique to measure the concentration of Pt in blood and perfusate.The amount of Pt recovered from the blood and perfusate samples spiked with analita was observed to be meanly of 95% with 5–6% of R.S.D. These results indicated that proposed method for the determination of platinum in biological materials is accurate and reproducible.The amounts of platinum found in the blood samples of common ranged citizen were similar to quantification limit while in the patients the concentration ranged from 1.5 to 360 μg/L, in perfusate ranged from 0.7 to 9700 μg/l. The concentrations of Pt of populace and in patients before of infusion are in agreement with the level measured in the blood of unexposed patients.The proposed analytical method permits to determine the amount of Pt in the perfusate and subsequently absorbed by the target organs in order to determine the dose and timing of treatment and to avoid overdoses with related undesired effects.     

EFFECT OF EXPOSURE TO LIGHT ON ENZYME ACTIVITIES and TRYPTOPHAN METABOLITES OF THE KYNURENINE PATHWAY IN WISTAR, IN HETEROZYGOUS and HOMOZYGOUS ADULT and NEWBORN GUNN RATS

Abstract— The purpose of this study was to determine the influence of phototherapy used in the treatment of hyperbilirubinemia in infants, on tryptophan metabolism and on enzyme activities involved along the kynurenine pathway in Wistar, icteric homozygous and nonicteric heterozygous Gunn rats after an intraperitoneal loading of 1.0 g/kg body weight L-tryptophan before and after exposure to visible light. The total mean 24-h excretion of the tryptophan metabolites in the groups of the Wistar and heterozygous Gunn rats was higher in females than in males and higher than in homozygous groups before phototherapy. Only after exposure to light did the groups of Wistar and heterozygous Gunn rats of both sexes show a decrease in the total excretion of the metabolites. The activities of tryptophan pyrrolase and kynureninase in liver and kynurenine aminotransferase in liver and kidneys were assayed in each group of rats. Male and female Wistar and heterozygous Gunn rats showed a higher activity of tryptophan pyrrolase than the groups of homozygotes in agreement with the data of the metabolites excreted. No difference in enzyme activities was found between the groups of heterozygous and homozygous neonates before and after phototherapy. Phototherapy did not seem to influence these enzyme activities.     

State-of-the-art of membrane bioreactors: Worldwide research and commercial applications in North America

Membrane bioreactor (MBR) technology is advancing rapidly around the world both in research and commercial applications. Despite the increasing number of studies and full-scale applications of MBR systems, directions and trends in academic research as well as commercial developments require further analysis. This paper aims to critically characterize and review worldwide academic research efforts in the area of MBRs as well as focus attention to commercial MBR applications in North America. A total of 339 research papers published in peer-reviewed international journals from 1991 to 2004 and a total of 258 full-scale MBR installations in North America were used as the database for the analysis provided in this paper. After a surge of MBR publications in 2002, research appears to have reached a plateau in the last 3 years using both submerged and external MBR units. Although much of the pioneering research occurred in Japan, France and the UK, countries such as South Korea, China and Germany have significantly contributed to the research pool in the last 5 years. The primary research focus has been on water filtration MBRs with limited growth in extractive and gas diffusion MBRs which still hold un-tapped potential. Fundamental aspects studied in academic research predominantly involve issues related to fouling, microbial characterization and optimizing operational performance. Research in North America presents a unique picture as a higher ratio of industrial wastewater treatment and side-stream MBR applications have been studied compared to other parts of the world. For MBR commercial application, the North America installations constitute about 11% of worldwide installations. Zenon occupies the majority of the MBR market in North America, whereas Kubota and Mitsubishi-Rayon have a larger number of installations in other parts of the world. Due to more stringent regulations and water reuse strategies, it is expected that a significant increase in MBR plant capacity and widening of application areas will occur in the future. Potential application areas include nitrate removal in drinking water treatment, removal of endocrine disrupting compounds from water and wastewater streams, enhancing bio-fuels production via membrane assisted fermentation and gas extraction and purification MBRs.     

Crystal structure transformations in ammonium and alkali metal perchlorates

A comparative study of the polymorphic transformations in ammonium and the alkali metal perchlorates has been made using differential thermal analysis. Certain correlations have been attempted between the observed trends in the transformation temperatures and available crystallographic and thermodynamic data. The transformation in the case of sodium perchlorate shows pronounced second-order effects. Considerable hysteresis is observed in the transformations in ammonium, potassium, rubidium and caesium perchlorates. Doping of ammonium perchlorate with ammonium phosphate is seen to result in an upward shift in the transformation temperature and an increase in the thermal hysteresis. Prior mechanical and thermal treatment is also seen to result in a broadening of the hysteresis loops in the case of ammonium and potassium perchlorates. The results are explained in terms of contrapolarization effects and the production of strain in the material as a result of prior treatment.     

PHOTOCHEMISTRY OF QUINOLYLMETHYLISOTHIORONIUM SALTS. GUANINE SELECTIVE DNA PHOTOCLEAVAGE REAGENTS

Quinolylmethylisothioronium salts (1a and 4a) cleave DNA upon irradiation. The cleavage is more than 10-fold enhanced by piperidine treatment and subsequently shows a high preference for guanines. Photolysis of 1a, 2a and 4a in water at lambda greater than 300 nm resulted in photoheterolysis. Irradiation of 1a in 2-propanol gave only products from photohomolysis, irradiation of 1a in methanol and 2a and 4a in 2-propanol resulted in products from both photoheterolysis and photohomolysis. Quantum yields for the disappearance of 1a in water and 2-propanol were determined. The presence or absence of oxygen had no effect in water, whereas oxidation products were observed upon irradiation in methanol and 2-propanol in the presence of oxygen. The guanine specific DNA photoreaction is proposed to take place by alkylation at N7 via the quinolylmethyl carbocation and thus to represent a photoalkylation.     

Evaluation of the Fate of Aldicarb and Its Metabolites in Oranges

Abstract

The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples. Residue concentrations measured in the soil samples were highly variable but a relation with the organic matter content can be observed. The residue levels found in vegetal products were higher in leaves than in rind, and in rind than in pulp. The maximum residue values were obtained between 47 and 70 days after the application. One hundred days after treatment (Security period) the residue levels of total fruit were lower than the maximum residue level of 0.2 mg/kg established by law.     

Patents and literature biocatalysis in nonaqueous media

Biocatalysis in nonaqueous media is being used in increasing regularity both in academic and industrial research. A variety of biocatalysts have been used in organic media including enzymes, multi-enzyme systems, and whole cells. In addition, the nonaqueous media has encompassed both monophasic and biphasic solvent systems, enzymes and whole cells in reversed micelles, enzymes and cells in nearly anhydrous (no added water) solvents, and enzymes catalytically active in supercritical fluids and the gas phase. Recent US and overseas patents and scientific literature on biocatalysis in nonaqueous media are surveyed. Patent abstracts are summarized individually, and literature references are divided into major subheadings.     

Spectral properties of the Cu-hyperaccumulating moss Scopelophilacataractae

To determine the characteristics of a Cu-hyperaccumulating moss Scopelophilacataractae and the influence of Cu on its structure and on chlorophyll (Chl), we measured reflectance and fluorescence (FL) spectra of S.cataractae samples with different Cu concentrations before and after wetting and the absorption spectra of Chl extracted from these samples. We found relationships between the spectral properties and Cu concentration. These relationships can be explained as follows. The higher the Cu concentration is, the lower is the plasticity of the cell wall, and the smaller is the increase in illuminated area due to the opening of the leaves after wetting. This results in a smaller increase in absorption and smaller decrease in reabsorption of the FL by Chl itself, and accordingly, a smaller increase in the FL band of Chl after wetting. Moreover, we found that the Chl concentration in S.cataractae is much higher than that in other common mosses and is correlated with an increase in the FL band of Chl after wetting. The remarkable increase in FL seen in S.cataractae and the slight increase in FL observed in other common mosses after wetting can be explained based on these findings.