bluuebunny/crossref_metadata_2025 huggingface dataset:
Daily cycles of suspended sand at coral reefs: A biological control
Authors: Yahel Ruthy , Yahel Gitai , Genin Amatzia
Published: June 2010

Sediment resuspension has a major ecological role in many coastal habitats, lakes, and marine environments. Waves and currents are generally thought to be the major control on sediment resuspension. In this study, the temporal and spatial distributions of suspended sand concentrations (SSAC) were measured at five coral reefs in the northern Gulf of Aqaba, Red Sea, by directly filtering seawater through 100‐ цm mesh nets. Levels of nearbottom SSAC were twice as high during the day (4.8–9.7 mg m-3) than at night (2.3–5.2 mg m-3). Vertical profiles showed a sharp increase of SSAC (2–6‐fold) toward the bottom during the daytime but not at night. The contributions of wind, waves, and currents to variations in SSAC were nonsignificant except during rare southern storms. Temporal and spatial changes in the level of SSAC during the day corresponded with the abundance of benthivorous fish and their activity pattern. Resuspension activities by fish numbered ›1.5 resuspension events m2 h-1 and were confined to daytime. An in situ experiment in which fish were excluded from a large section (250 m2) of the reef resulted in elimination of the day‐night differences and a significant decrease in daytime SSAC over the treated reef section in comparison to the open, control sites. This study is the first report of a daily pattern of suspended sediment at coral reefs with fish activity as its causative agent.
Plasticity in vertical migration by native and exotic estuarine fishes in a dynamic low‐salinity zone
Authors: Bennett William A. , Kimmerer Wim J. , Burau Jon R.
Published: June 2010

We investigated the degree of flexibility in retention strategies of young fishes in the low‐salinity zone (LSZ) of the San Francisco Estuary during years of highly variable river flow. We conducted depth‐stratified sampling over three full tidal cycles in each year from 1994 to 1996. In 1994, exotic striped bass (Morone saxatilis), native longfin smelt (Spirinchus thaleichthys), and exotic yellowfin goby (Acanthogobus flavimanus) migrated tidally, occurring near the surface on flood tides and near the bottom on ebb tides. This strategy may have facilitated retention, because landward residual currents were absent in this drought year. During 1995, this behavior persisted for striped bass and yellowfin goby, even though landward residual currents were present under high river‐flow conditions. In moderate river‐flow conditions (1996), longfin smelt again migrated tidally, whereas at another station adjacent to shallow bays, longfin smelt, striped bass, and native delta smelt (Hypomesus transpacificus) migrated on a reverse diel cycle, occurring near the surface by day and at depth by night. Reverse diel migration may facilitate horizontal transport and retention. Therefore, young fishes appeared to be behaviorally flexible in different environmental conditions to maximize retention. Vertical migrations may also enhance feeding success because zooplankton prey similarly migrated in the LSZ. Our study underscores the value of interdisciplinary studies in a variety of environmental conditions to decipher the range of organism behaviors promoting transport and retention in optimal habitats.
Photochemical, chemical, and biological transformations of dissolved organic carbon and its effect on alkalinity production in acidified lakesJi
Authors: Kopáček Jiŕí , Hejzlar Josef , Kaňa Jiŕí , Porcal Petr , Klementová Šárkárka
Published: June 2010

We evaluated the significance of photochemical and biological degradation of allochthonous dissolved organic carbon (DOC) on in‐lake H+ budgets by laboratory experiments and with a mass budget study for major ions in three atmospherically acidified forest lakes in the Bohemian Forest. In the experiments, photodegradation of DOC from a lake tributary resulted in (1) a liberation of organically bound Al and Fe, which consumed an equivalent amount of H+, (2) a minor decrease in concentrations of organic acid anions (A−) despite a major decrease in DOC concentrations, and (3) the production of biologically available DOC. Biological degradation of the photochemically transformed DOC resulted in a lesser decrease in DOC concentrations than during photodegradation (28—45% of the total decline) but in a pronounced decrease in A− concentrations (64—85% of the total decline), leading to a significant pH increase. Hydrolysis of photoliberated metals under increasing pH partly reduced net H+ consumption within the whole process. Watersheds of the lakes studied exported more SO42−, NO3−, and H+ than they received by throughfall, and the lakes were the dominant acidity‐consuming parts of the whole ecosystems, neutralizing 50—58% of H+ input. In‐lake photochemical, biological, and chemical changes in A− fluxes consumed 56—190 meq m−2 yr−1 of H+ and were the third major internal alkalinity‐producing mechanism after the biochemical reduction of NO3− and SO42− (333—396 and 143—214 meq m−2 yr−1, respectively). In contrast, the hydrolysis of inorganic Al was the dominant in‐lake H+‐producing process (144—340 meq m−2 yr−1). The in‐lake A− removal was positively related to the DOC loading. Consequently, changes in DOC and A− fluxes should not be omitted in alkalinity budgets in lakes with low or no bicarbonate concentration and elevated DOC input.
Chemical defense in the microplankton II: Inhibition of protist feeding by β‐dimethylsulfoniopropionate (DMSP)
Authors: Strom Suzanne , Wolfe Gordon , Slajer Amy , Lambert Sarah , Clough Jennifer
Published: June 2010

Examples of chemical defenses and their influence on predator–prey interactions abound in the terrestrial and marine benthic ecological literature. In contrast, considerably less is known about the role of chemical defenses in marine planktonic systems. In this study, we examined the potential for the phytoplankton‐produced compound dimethylsulfoniopropionate (DMSP) and its cleavage products dimethyl sulfide (DMS) and acrylate to act as chemical defenses in seawater. Although added DMS and acrylate had no effect on protist grazers, added DMSP reduced grazing on the coccolithophorid Emiliania huxleyi by all four tested species (dinoflagellates Amphidinium longum, Gymnodinium sp., and Oxyrrhis marina and ciliate Coxliella sp.). A. longum and Gymnodinium were highly sensitive to 20‐ µmol L−1 concentrations of DMSP, nearly ceasing to feed, whereas O. marina and Coxliella showed only minor reductions in grazing activity. Grazing suppression in A. longum was DMSP concentration‐dependent over the range 0.05 to 1,000 µmol L−1 and was also inhibited by added glycine betaine, a structural analog of DMSP. DMSP reduced A. longum grazing by similar amounts on five different algal species, some of which do not produce DMSP on their own. Thus, the efficacy of DMSP as a grazing deterrent appears to depend on grazer species, but not on algal strain or species. Because DMSP does not seem to be toxic, we hypothesize that DMSP and related compounds act as signals for the presence of potentially harmful algal cells. Should such sublethal chemical defense interactions be widespread in nature, they could be important in regulating the composition and biomass of phytoplankton communities.
Control of zooplankton dependence on allochthonous organic carbon in humic and clear‐water lakes in northern Sweden
Authors: Karlsson Jan , Jonsson Anders , Meili Markus , Jansson Mats
Published: June 2010

We compared the stable carbon isotopic composition (δ13C) of crustacean zooplankton with that of potential carbon sources in 15 lakes in northern Sweden with different dissolved organic carbon (DOC) concentrations (2‐9 mg L−1) to test the hypothesis that zooplankton depended more on allochthonous carbon in humic lakes than in clear‐water lakes. Based on δ13C signature, we found that the pool of organic matter in the lakes was dominated by carbon of allochthonous origin over the whole DOC gradient. Zooplankton were generally depleted in 13C compared to organic matter in the catchment, particulate organic matter in the lake water, and shallow surface sediment. However, the isotopic composition of zooplankton could not be explained without a significant contribution from both allochthonous and autochthonous carbon sources in all lakes. The relative importance of these two carbon sources did not relate to the concentration of, or proportion between, allochthonous and autochthonous organic carbon in the water. Instead, the proportion between allochthonous and autochthonous carbon in the crustacean zooplankton was consistent with a rather conservative use of the energy mobilized by bacterioplankton and phytoplankton in the lakes.
Remote assessment of benthic substrate composition in shallow waters using multispectral reflectance
Authors: Werdell P. Jeremy , Roesler Collin S.
Published: June 2010

We investigated the utility of quantifying percent coverage of benthic substrate constituents from surface multispectral reflectance measurements. Six substrates were considered: kelp, eelgrass, clay, silt, mineralic sand from a temperate environment, and turtlegrass and carbonate sand from a tropical environment. Each had a unique albedo spectrum that contributes differently to the upward light field in an optically shallow environment. Simplifications to the radiative transfer equation yield an analytic solution for surface reflectance in optically shallow environments. The objectives were to test the inverse model to predict bottom albedo from measurements of surface reflectance, diffuse attenuation, and water depth in the turbid water of eastern Long Island Sound, Connecticut, and clear waters off Exuma, Bahamas. A linear mixing model was used to deconvolve the derived albedo spectra into contributions by the six constituents. The inverse and deconvolution models accurately identified the dominant substrate in the six homogeneous habitats (single point determinations) and predicted the gradient in substrate composition along transects. This approach has applications to benthic survey mapping, habitat assessment, and habitat monitoring.
From regional climate simulations to the hydrological information needed for basin scale impact studies
Authors: Portoghese I. , Bruno E. , Vurro M.
Published: June 2010

Abstract. The accuracy of local downscaling of rainfall predictions provided by climate models is crucial for the assessment of climate change impacts on hydrological processes because the presence of bias in downscaled precipitation may produce large bias in the assessment of soil moisture dynamics, river flows, and groundwater recharge. In this study, the output of a regional climate model (RCM) is downscaled using a stochastic modelling of the point rainfall process able to adequately reproduce the daily rainfall intermittency which is one of the crucial aspects for the hydrological processes characterizing Mediterranean environments. The historical time-series from a dense rain-gauge network were used for the analysis of the RCM bias in terms of dry and wet daily period and then to investigate the predicted alteration in the local rainfall regime. A Poisson Rectangular Pulse (PRP) model (Rodriguez-Iturbe et al., 1987) was finally adopted for the stochastic generation of local daily rainfall as a continuous-time point process with forcing parameters resulting from the bias correction of the RCM scenario.
Subchronic toxic effects of fusarium moniliforme and fumonisin B1 in rats and mice
Authors: Voss Kenneth A. , Riley Ronald T. , Bacon Charles W. , Chamberlain William J. , Norred William P.
Published: June 2010

Fumonisins are mycotoxins produced by the fungi Fusarium moniliforme, F. proliferatum, and other Fusarium species. Fumonisin B1, the most commonly found fumonisin, causes the fatal diseases equine leukoencephalomalacia and porcine pulmonary edema. Fumonisins are suspected human carcinogens because of the extraordinarily high incidences of esophageal cancer coincidentally found in areas of southern Africa and China where F. moniliforme‐contaminated corn is consumed as a dietary staple. The subchronic (up to 90 days) effects of F. moniliforme‐contaminated corn, corn cultures of this fungus, and purified fumonisin B1 (FB1) in rats and mice were systematically studied to determine target organs, characterize organ‐specified lesions, and obtain dose‐response data. The liver is a target organ in both species. Serum chemical findings indicative of hepatocellular injury and morphological findings, including apoptosis, appeared qualitatively similar in both species. The kidney is also a target organ in rats, but not mice. Lesions which include apoptosis and cellular degeneration are predominately found in the outer medella. Results of several investigations showed that the kidney was consistently affected at lower doses than the liver. The “no‐observed‐effect” level for nephropathy in rats was also consistently lower in males than females, suggesting a sex‐related difference in nephrotoxic response to fumonisins. Other findings suggest that toxigenesis may be mediated by disruption of de novo sphingolipid biosynthesis. Hepatic and renal sphingolipid profiles, specifically sphinganine concentration and sphinganine‐to‐sphingosine ratio, were altered in rats fed FB1 at levels that did not cause serum chemical, organ weight, or histopathological evidence of toxicity.
Leukoencephalomalacia and hemorrhage in the brain of rabbits gavaged with mycotoxin fumonisin B1
Authors: Bucci Thomas J. , Hansen Deborah K. , Laborde James B.
Published: June 2010

Two of five pregnant rabbits gavaged with purified fumonisin B1 at 1.75 mg/kg/day died, one after 9 and one after 13 doses. Microscopic examination revealed focal small hemorrhages in cerebral white matter in both animals, with malacia and hemorrhage also present in the hippocampus of one. The lesions were bilateral. Both animals also had marked degeneration of renal tubule epithelium and of hepatocytes. Apoptosis was the dominant degenerative change in kidney and liver.

Fumonisin is known to cause leukoencephalomalacia and hemorrhage in equines, but CNS changes associated with exposure to fumonisins apparently have not been reported in other species. This preliminary observation in rabbits is reported to alert other investigators of a potential model of the disease in equines, as well as for investigation of potential mechanisms of toxicity to the CNS. c̊ 1996 Wiley‐Liss, Inc.
Simultaneous occurrence of diarrhetic and paralytic shellfish poisoning toxins in Spanish mussels in 1993
Authors: Gago‐Martinez Ana , Rodriguez‐Vazquez José A. , Thibault Pierre , Quilliam Michael A.
Published: June 2010

Mussel aquaculture is an important industry for the Galician Rias, located in northwestern Atlantic coast of Spain. Since 1976 this region has been seriously affected by incidents of paralytic and diarrhetic shellfish poisoning (PSP and DSP). A particularly bad epidode occurred in 1993, when the toxic event lasted for an unusually long period. Many people were stricken ill with unusual symptoms. In this paper we report on the chemical analysis of toxic 1993 mussel samples, using the techniques of liquid chromatography and capillary electrophoresis coupled with mass spectrometry. These analyses revealed a very complex toxin profile, with both PSP and DSP toxins present. Two DSP toxins, okadaic acid and DTX2, were observed, while the primary PSP toxins were B1 and the decarbamoylated derivatives of saxitoxin, GTX2 and GTX3. Small amounts of saxitoxin and other as yet unidentified PSP toxins were observed.
Lichen acids as uncouplers of oxidative phosphorylation of mouse‐liver mitochondria
Authors: Abo‐Khatwa A. N. , Al‐Robai A. A. , Al‐Jawhari D. A.
Published: June 2010

Three lichen acids—namely, (+)usnic acid, vulpinic acid, and atranorin—were isolated from three lichen species (Usnea articulata, Letharia vulpina, and Parmelia tinctorum, respectively). The effects of these lichen products on mice‐liver mitochondrial oxidative functions in various respiratory states and on oxidative phosphorylation were studied polarographically in vitro. The lichen acids exhibited characteristics of the 2,4‐dinitrophenol (DNP), a classical uncoupler of oxidative phosphorylation. Thus, they released respiratory control and oligomycin inhibited respiration, hindered ATP synthesis, and enhanced Mg2+‐ATPase activity. (+)Usnic acid at a concentration of 0.75 μM inhibited ADP/O ratio by 50%, caused maximal stimulation of both state‐4 respiration (100%) and ATPase activity (300%). Atranorin was the only lichen acid with no significant effect on ATPase. The uncoupling effect was dose‐dependent in all cases. The minimal concentrations required to cause complete uncoupling of oxidative phosphorylation were as follows: (+)usnic acid (1 μM), vulpinic acid, atranorin (5 μM) and DNP (50 μM). It was postulated that the three lichen acids induce uncoupling by acting on the inner mitochondrial membrane through their lipophilic properties and protonophoric activities.
Fluoroacetate content of some species of the toxic Australian plant genus, gastrolobium, and its environmental persistence
Authors: Twigg Laurie E. , King Dennis R. , Bowen Lynn H. , Wright Geoffrey R. , Eason Charles T.
Published: June 2010

Gas chromatography confirmed the relatively high concentrations of fluoroacetate found in toxic Gastrolobiums, a genus of indigenous Australian plants. Fluoroacetate concentration in these plants ranged from 01 to 3875 μg/g (ppm) dry weight, with young leaves and flowers containing the highest concentrations However, there was considerable intrastand variation between individual plants of at least two species with coefficients of variation ranging from 94% to 129%. Despite the high concentrations of fluoroacetate in many species, only one of nine soil samples collected from beneath these plants contained fluoroacetate None of the 16 water samples collected from nearby streams and catchment dams contained fluoroacetate. This suggests that fluoroacetate does not persist in this environment. Fluoroacetate was also found in the genus Nemcia, and very low levels of fluoroacetate (ng/g) were detected in the foodstuffs, tea and guar gum The latter indicates that other plant species may produce biologically insignificant amounts of fluoroacetate
A saporin‐insulin conjugate: Synthesis and biochemical characterization
Authors: Ippoliti Rodolfo , Lendaro Eugenio , Bellelli Andrea , Fiani Maria Luisa , Benedetti Pier Alberto , Evangelista Valtere , Brunori Maurizio
Published: June 2010

Saporin, a single‐chain, non‐cytotoxic, ribosome‐inactivating protein from Saponaria officinalis, was chemically linked to the hormone insulin in a 1:1 complex. To follow by dynamic video microscopy the endocytosis and intracellular transport in vivo, a second covalent conjugate with a saporin derivative labelled with fluorescein isothiocyanate was also prepared. Both conjugates were characterized with reference to homogeneity, stoichiometry, optical spectroscopy and toxicity. Both were found to exhibit scarce toxicity toward both CHO and HEP G2 cells; optical video microscopy on living cells indicates that reduced toxicity may be (partly) due to a very limited binding of the saporin‐insulin conjugate to membrane receptors. These results suggest a strategy for new possible covalent conjugates of saporin with alternative and specific macromolecular carners
Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (symphytum officinale)
Authors: Couet Carole E. , Crews Colin , Hanley A. Bryan
Published: June 2010

Pyrrolizidine alkaloids have been linked to liver and lung cancers and a range of other deleterious effects. As with many natural toxicants, major problems arise in determining the effects of the different members of the class and the importance of various forms of ingestion. In this study we have investigated the levels of pyrrolizidine alkaloids in comfrey (Symphytum officinale), determined the levels in different parts of the plant and in herbal remedies, separated the alkaloids into two main groups— the principal parent alkaloids and the corresponding N‐oxides—and, finally, carried out a simple bioassay based upon the mutagenic capability of the separated compounds in a human cell line. We conclude that the part of the plant ingested is important in terms of alkaloid challenge and that the effect of two of the major groups of alkaloids individually is different from that of alkaloids in the whole plant extract.
Facile Functionalization and Phase Reduction Route of Magnetic Iron Oxide Nanoparticles for Conjugation of Matrix Metalloproteinase
Authors: Li Dan , Teoh Wey Yang , Djunaedi Diana , Gooding Jolen Justin , Selomulya Cordelia , Amal Rose
Published: June 2010

A protocol for the simultaneous functionalization and phase reduction route of iron oxide magnetic nanoparticles (MNPs) and its further bioconjugation is presented. It was found that surface functionalization of maghemite (γ‐Fe2O3) nanoparticles with mercaptopropyltrimethoxysilane (MPTMS) under anoxic environment at above 80 °C promotes in situ conversion to magnetite (Fe3O4). Full conversion to Fe3O4, as probed by Mössbauer spectroscopy, with accompanied increase in the composite saturation magnetization, was achieved at 120 °C. By controlling the MPTMS concentration, the resultant silane‐MNPs morphology can be tuned from having homogeneous thin layer (<1 nm) to thick continuous silane with embedded MNP multicores. Likewise the amount of surface distal thiol moieties was dependent on the silanization conditions. The density of distal thiols (i.e., amount of thiol per surface area) and resultant aggregate size have direct impact on the attachment, as well as the activity and reusability of the conjugated matrix metalloproteinase (MMP‐2, using sulfo‐SMCC as crosslinker). The work has important implication to the field of magneto‐chemotherapeutics, where spatial control of conjugated active biomolecules under magnetic field and T2‐weighted MRI contrast can be achieved simultaneously.
Proteolytically Degradable Photo‐Polymerized Hydrogels Made From PEG–Fibrinogen Adducts
Authors: Dikovsky Daniel , Bianco‐Peled Havazelet , Seliktar Dror
Published: June 2010

We develop a biomaterial based on protein–polymer conjugates where poly(ethylene glycol) (PEG) polymer chains are covalently linked to multiple thiols on denatured fibrinogen. We hypothesize that conjugation of large diacrylate‐functionalized linear PEG chains to fibrinogen could govern the molecular architecture of the polymer network via a unique protein–polymer interaction. The hypothesis is explored using carefully designed shear rheometry and swelling experiments of the hydrogels and their precursor PEG/fibrinogen conjugate solutions. The physical properties of non‐cross‐linked and UV cross‐linked PEGylated fibrinogen having PEG molecular weights ranging from 10 to 20 kDa are specifically investigated. Attaching multiple hydrophilic, functionalized PEG chains to the denatured fibrinogen solubilizes the denatured protein and enables a rapid free‐radical polymerization cross‐linking reaction in the hydrogel precursor solution. As expected, the conjugated protein‐polymer macromolecular complexes act to mediate the interactions between radicals and unsaturated bonds during the free‐radical polymerization reaction, when compared to control PEG hydrogels. Accordingly, the cross‐linking kinetics and stiffness of the cross‐linked hydrogel are highly influenced by the protein–polymer conjugate architecture and molecular entanglements arising from hydrophobic/hydrophilic interactions and steric hindrances. The proteolytic degradation products of the protein–polymer conjugates proves to be were different from those of the non‐conjugated denatured protein degradation products, indicating that steric hindrances may alter the proteolytic susceptibility of the PEG–protein adduct. A more complete understanding of the molecular complexities associated with this type of protein‐polymer conjugation can help to identify the full potential of a biomaterial that combines the advantages of synthetic polymers and bioactive proteins.
Stable Non‐Covalent Large Area Patterning of Inert Teflon‐AF Surface: A New Approach to Multiscale Cell Guidance
Authors: Valle Francesco , Chelli Beatrice , Bianchi Michele , Greco Pierpaolo , Bystrenova Eva , Tonazzini Ilaria , Biscarini Fabio
Published: June 2010

Micro‐ and nano‐patterning of cell adhesion proteins is demonstrated to direct the growth of neural cells, viz. human neuroblastoma SHSY5Y, at precise positions on a strongly antifouling substrate of technolological interest. We adopt a soft‐lithographic approach with oxygen plasma modified PDMS stamps to pattern human laminin on Teflon‐AF films. These patterns are based on the interplay of capillary forces within the stamp and non‐covalent intermolecular and surface interactions. Remarkably, they remain stable for several days upon cell culture conditions. The fabrication of substrates with adjacent antifouling and adhesion‐promoting regions allows us to reach absolute spatial control in the positioning of neuroblastoma cells on the Teflon‐AF films. This patterning approach of a technologically‐relevant substrate can be of interest in tissue engineering and biosensing.
Homogene Gold‐Katalyse jenseits von Vermutungen und Annahmen – charakterisierte Intermediate
Authors: Hashmi A. Stephen K.
Published: June 2010

Die Gold‐Katalyse ist ein sehr aktives Gebiet im Feld der Katalyseforschung. Wöchentlich werden neue Reaktionen publiziert, oft werden erstaunliche Konnektivitätsänderungen beobachtet, die Zahl der Anwendungen in der Totalsynthese steigt …︁ – aber was sind die Mechanismen dieser Reaktionen? Fundierte Informationen können aus dem Wissen über Zwischenstufen dieser Reaktionen erhalten werden.
Formtreue organische Käfigverbindungen durch dynamische Bildung kovalenter Bindungen
Authors: Mastalerz Michael
Published: June 2010

Ein Bereich der supramolekularen Chemie umfasst die Synthese diskreter dreidimensionaler Aggregate durch Koordination von Übergangsmetallen. Ein Teil dieses Gebiets ist die Chemie der supramolekularen Käfigverbindungen, die durch Knüpfung koordinativer Bindungen entstehen. Heute kennt man ein breites Spektrum solcher supramolekularen Koordinationskäfige. Relativ selten sind jedoch analoge organische Käfigverbindungen, die aus kovalenten Bindungsbildungen resultieren. In letzter Zeit wurden auf diesem Gebiet einige wichtige Fortschritte erzielt, nicht zuletzt durch Anwendung neuer Konzepte wie der dynamischen kovalenten Chemie. Diese Konzepte machen es möglich, organische Käfigverbindungen in wenigen Stufen und guten Ausbeuten zu synthetisieren, und das meist aus einfach zugänglichen Ausgangsverbindungen.
Erratum: A novel catalyst for the glycolysis of poly(ethylene terephthalate) K. Troev, G. Grancharov, R. Tsevi, I. Gitsov. Journal of Applied Polymer Science, 2003; 90: 1148–1152
Authors: Troev K. , Grancharov G. , Tsevi R. , Gitsov I.
Published: June 2010

The original article to which this Erratum refers was published in Journal of Applied Polymer Science, 90, (4) 2003, 1148–1152.

No abstract.
New polyol for production of rigid polyurethane‐polyisocyanurate foams, Part 2: Preparation of rigid polyurethane‐polyisocyanurate foams with the new polyol
Authors: Paciorek‐Sadowska Joanna , Czupryński Bogusław , Liszkowska Joanna
Published: June 2010

The method of preparation, determination of foaming parameters, and methods for the determination of physicochemical properties of polyurethane‐polyisocyanurate (PUR‐PIR) foams prepared with the use of N,N′‐di(methyleneoxy‐2‐hydroxyethyl)urea and boric acid derivatives are presented in this paper. It was found that application of the borate as a polyol component and simultaneously as a flame retardant in the recipe for production of PUR‐PIR foams was very favorable. The foams prepared were characterized by reduced brittleness, higher compressive strength and content of closed cells, as well as considerably lower flammability in comparison with standard foam. The results show that the new polyol prepared on the basis of N,N′‐di(methyleneoxy‐2‐hydroxyethyl)urea and boric acid can be applied for production of rigid PUR‐PIR foams, and it improves their physicochemical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Dry‐jet‐wet spun polyurethane fibers. I. Optimization of the spinning parameters
Authors: Reddy G. V. Raghunath , Deopura B. L. , Joshi Mangala
Published: June 2010

This study examined the spinning of polyurethane‐based elastomeric fibers with the dry‐jet‐wet spinning method. The three important spinning variables that were chosen were the coagulation bath ratio (dimethylformamide/water), the bath temperature, and the stretch ratio. A three‐variable factorial design method, proposed by Box and Behnken, was used to optimize these process parameters. The spinning process was further fine‐tuned by the variation of the stretch ratio and the dope solid content. The effect of the dry‐jet length on the fiber properties was also studied. The tenacity and elastic recovery properties of the fibers were found to be optimum at a bath ratio (dimethylformamide/water) of 60 : 40, a bath temperature of 15°C, and a stretch ratio of 2.5. The density and sonic modulus were measured to determine the effect of varying the process variables on structural parameters such as the density and orientation. The surface morphological features, as revealed by scanning electron microscopy, were correlated to the fiber properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of positively charged nanofiltration membrane from 2‐hydroxypropyltrimethyl ammonium chloride chitosan by 1,4‐butanediyl diglycidyl ether cross‐linking
Authors: Huang Ruihua , Chen Guohua , Yang Bingchao , Gao Congjie
Published: June 2010

A novel positively charged composite nanofiltration (NF) membrane was prepared using 2‐hydroxypropyltrimethyl ammonium chloride chitosan as active layer, polyacrylonitrile ultrafiltration membrane as substrate layer, and 1,4‐butanediol diglycidyl ether as cross‐linking reagent. The observation from scanning electron microscope revealed its composite structure. At room temperature and cross‐flow rate of 40 L h−1, the permeability for pure water was 14.3 L h−1 m−2 MPa−1. With an increase in operating pressure, the flux increased linearly. The rejection to different salt solutions was decreasing in the order of CaCl2, MgCl2, MgSO4, NaCl, and Na2SO4, revealing the rejection characteristic of positively charge NF membrane. And it had good ion perm‐selectivity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Enhancement of glutaryl‐7‐aminocephalosporanic acid acylase activity of γ‐glutamyltranspeptidase of Bacillus subtilis
Authors: Suzuki Hideyuki , Yamada Chiaki , Kijima Kyoko , Ishihara Sayaka , Wada Kei , Fukuyama Keiichi , Kumagai Hidehiko
Published: June 2010

Semisynthetic cephalosporins, the best‐selling antibiotics worldwide, are derived from 7‐aminocephalosporanic acid (7‐ACA). Currently, in the pharmaceutical industrie, 7‐ACA is mainly produced from cephalosporin C by sequential application of D‐amino acid oxidase and cephalosporin acylase. Here we study the potential of industrially amenable enzyme γ‐glutamyltranspeptidase from Bacillus subtilis for 7‐ACA production, since the wild‐type γ‐glutamyltranspeptidase of B. subtilis has inherent glutaryl‐7‐aminocephalosporanic acid acylase activity with a kcat value of 0.0485 s‐1. Its activity has been enhanced by site directed and random mutagenesis. The kcat/Km value was increased to 3.41 s‐1 mM‐1 for a E423Y/E442Q/D445N mutant enzyme and the kcat value was increased to 0.508 s‐1 for a D445G mutant enzyme. Consequently, the catalytic efficiency and the turnover rate were improved up to about 1000‐fold and 10‐fold, compared with the wildtype γ‐glutamyltranspeptidase of B. subtilis.
Die Geschichte der Kolibakterien. Vom Darmbewohner zum Bioreaktor
Authors: Steverding Dietmar
Published: June 2010

Das von Theodor Escherich vor 125 Jahren entdeckte E. coli‐Bakterium hat wie kein anderes die Entwicklung der molekularbiologischen Forschung und der medizinischen und industriellen Biotechnologie beeinflusst. Vor allem die Eigenschaften des K12‐Stammes im Hinblick auf Apathogenität, Kultivierbarkeit und Transformierbarkeit haben E. coli zum “Haustier” der Genetiker und Molekularbiologen gemacht. Die Leichtigkeit, mit der gentechnisch veränderte E. coli hergestellt werden können, ließen dieses Bakterium zum beliebten Produktionsorganismus in der modernen Biotechnologie zur Erzeugung von Medikamenten und Feinchemikalien werden. Als physiologischer Darmbewohner von Menschen und Tieren wird E. coli als Indikatororganismus für fäkale Verunreinigungen von Grund‐ und Trinkwasser verwendet. Neben seiner mikroökologischen Rolle im Magen‐Darm‐Trakt kommt ihm in Form von pathogenen Stämmen auch eine Bedeutung als Erreger von Durchfallerkrankungen zu.
Western‐Blot Teil 2: Die Immunreaktion
Authors: Schrödel Andrea
Published: June 2010

Mit einer Nachweisgrenze von 10–100 Femtomol ist der Western Blot ist eine sehr sensitive Methode, um bestimmte Proteine in einem Proteingemisch mit Hilfe spezifischer Antikörper zu identifizieren.
Ernst Haeckel
Authors: Kockerbeck Christoph
Published: June 2010

Ernst Haeckel wirkte als Professor der Zoologie an der Universität Jena und war einer der bedeutendsten Meereszoologen und einflussreichsten Evolutionstheoretiker des 19. Jahrhunderts.
Maleimide‐Modified Phosphonium Ionic Liquids: A Template Towards (Multi)Task‐Specific Ionic Liquids
Authors: Tindale Jocelyn J. , Hartlen Kurtis D. , Alizadeh Abdolhamid , Workentin Mark S. , Ragogna Paul J.
Published: June 2010

The synthesis and characterization of several compounds representing a new class of multitask‐specific phosphonium ionic liquids that contain a maleimide functionality is reported. The maleimide moiety of the ionic liquid (IL) is shown to undergo Michael‐type additions with substrates containing either a thiol or amine moiety, thus, serving as a template to introduce wide structural diversity into the IL. Multitask‐specific ILs are accessible by reaction of the maleimide with Michael donors that are capable of serving some function. As a model example to illustrate this concept, a redox active ferrocenyl thiol was incorporated and examined by cyclic voltammetry. Because the maleimide moiety is highly reactive to additions, the task‐specific ionic liquids (TSILs) are prepared as the furan‐protected Diels–Alder maleimide. The maleimide moiety can then be liberated when required by simple heating.
Switchable Cucurbituril–Bipyridine Beacons
Authors: Sinha Mantosh K. , Reany Ofer , Parvari Galit , Karmakar Ananta , Keinan Ehud
Published: June 2010

4‐Aminobipyridine derivatives form strong inclusion complexes with cucurbit[6]uril, exhibiting remarkably large enhancements in fluorescence intensity and quantum yields. The remarkable complexation‐induced pKa shift (ΔpKa=3.3) highlights the strong charge–dipole interaction upon binding. The reversible binding phenomenon can be used for the design of switchable beacons that can be incorporated into cascades of binding networks. This concept is demonstrated herein by three different applications: 1) a switchable fluorescent beacon for chemical sensing of transition metals and other ligands; 2) direct measurement of binding constants between cucurbit[6]uril and various nonfluorescent guest molecules; and 3) quantitative monitoring of biocatalytic reactions and determination of their kinetic parameters. The latter application is illustrated by the hydrolysis of an amide catalyzed by penicillin G acylase and by the elimination reaction of a β‐cabamoyloxy ketone catalyzed by aldolase antibody 38C2.
[4+2] Cycloaddition Reactions Between 1,8‐Disubstituted Cyclooctatetraenes and Diazo Dienophiles: Stereoelectronic Effects, Anticancer Properties and Application to the Synthesis of 7,8‐Substituted Bicyclo[4.2.0]octa‐2,4‐dienes
Authors: Grange Rebecca L. , Gallen Michael J. , Schill Heiko , Johns Jenny P. , Dong Lin , Parsons Peter G. , Reddell Paul W. , Gordon Victoria A. , Bernhardt Paul V. , Williams Craig M.
Published: June 2010

A detailed examination of [4+2] cycloaddition reactions between 1,8‐disubstituted cyclooctatetraenes and diazo compounds revealed that 4‐phenyl‐1,2,4‐triazole‐3,5‐dione (PTAD) reacts to form either 2,3‐ or 3,4‐disubstituted adducts. The product distribution can be controlled by modulating the electron density of the cyclooctatetraene. Unprecedented [4+2] cycloadditions between diisopropyl azodicarboxylate (DIAD) and 1,8‐disubstituted cyclooctatetraenes are also described and further manipulation of a resulting cycloadduct uncovered a new pathway to the synthetically challenging bicyclo[4.2.0]octa‐2,4‐diene family. Variation of the substituents resulted in a range of compounds displaying selective action against different human tumour cell types.
Sonochemical Preparation of Hierarchical ZnO Hollow Spheres for Efficient Dye‐Sensitized Solar Cells
Authors: He Chun‐Xiu , Lei Bing‐Xin , Wang Yu‐Fen , Su Cheng‐Yong , Fang Yue‐Ping , Kuang Dai‐Bin
Published: June 2010

Hierarchical ZnO hollow spheres (400–500 nm in diameter) consisting of ZnO nanoparticles with a diameter of approximately 15 nm have been successfully prepared by a facile and rapid sonochemical process. The formation of hierarchical ZnO hollow spheres is attributed to the oriented attachment and subsequent Ostwald ripening process according to time‐dependent experiments. The as‐prepared ZnO hollow spheres are used as a photoanode in dye‐sensitized solar cells and exhibit a highly efficient power conversion efficiency of 4.33 %, with a short‐circuit current density of 9.56 mA cm−2, an open‐circuit voltage of 730 mV, and a fill factor of 0.62 under AM 1.5 G one sun (100 mW cm−2) illumination. Moreover, the photovoltaic performance (4.33 %) using the hierarchical ZnO hollow spheres is 38.8 % better than that of a ZnO nanoparticle photoelectrode (3.12 %), which is mainly attributed to the efficient light scattering for the former.
Studies of 2‐Azaazulenium Derivatives: Unsymmetrical Trimethine Cyanine Dyes Bearing a 2‐Azaazulenium Moiety as One of the Terminal Groups
Authors: Bricks Julia , Ryabitskii Aleksey , Kachkovskii Alexei
Published: June 2010

We report here the synthesis of a series of symmetrical and unsymmetrical trimethine cyanine dyes derived from 2‐azaazulene, combined spectral and quantum‐chemical investigations of their molecular geometry and electron structure, as well as the nature of the lowest electron transitions. Based on the analysis of both calculations and experimental data obtained from absorption and13C NMR spectra, it was concluded that the 2‐azaazulene residue can be treated as a weakly basic terminal group; its donor properties are provided with the participation of the HOMO−1, in contrast to the typical Brooker’s terminal residues with their donor HOMOs. The new classification of the terminal groups of cyanine dyes, and hence the classification of types of unsymmetrical cyanines, is proposed. It is shown that the nature of the higher electron transitions (delocalized or local) in the cyanine dyes depends on their type. In the unsymmetrical trimethine cyanine of the mixed type, negative deviations are observed in their absorption spectra.
Pyrrole and Oligopyrrole Synthesis by 1,3‐Dipolar Cycloaddition of Azomethine Ylides with Sulfonyl Dipolarophiles
Authors: Robles‐Machín Rocío , López‐Pérez Ana , González‐Esguevillas María , Adrio Javier , Carretero Juan Carlos
Published: June 2010

A procedure for the synthesis of functionalized, substituted pyrroles by 1,3‐dipolar cycloaddition of azomethine ylides has been developed. This protocol is based on the metal‐catalyzed cycloaddition of α‐iminoesters with sulfonyl dipolarophiles, followed by the base‐promoted elimination of the sulfonyl groups. A wide variety of 2,5‐disubstituted and 2,3,5‐ and 2,4,5‐trisubstituted pyrroles have been prepared in satisfactory yields from 1,2‐bis(sulfonyl ethylene), β‐sulfonylenones, and β‐sulfonylacrylates. This method can be applied in an iterative and straightforward manner to the construction of oligopyrroles, from bipyrroles to pentapyrroles. Iterative [n+1] and [n+2] approaches have been devised, the latter involves double 1,3‐dipolar cycloaddition from pyrrolyl‐based bis(iminoesters).
ChemInform Abstract: Layer Structure of (NH4)CoPO4×H2O.
Authors: Yakubovich Olga V. , Karimova Oksana V. , Dimitrova Olga V. , Massa Werner
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: NH4VO(NH3)PO4.
Authors: Fratzky Dietmar , Worzala Horst , Goetze Thomas , Meisel Manfred
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structures of Monofluorosulfites MSO2F (M: K, Rb).
Authors: Kessler Ulrich , Jansen Martin
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ce2Ti2SiO9 — The First Titanate‐Silicate with Cerium — Preparation, Characterization, and Structure.
Authors: Zenser Lars‐Peter , Weil Matthias , Gruehn Reginald
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Excess Enthalpies of Liquid Ga—Pb—Te Alloys.
Authors: Blachnik R. , Klose E. , Roemermann F.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ion‐Pair and Solvent Relaxation Processes in Aqueous Na2SO4 Solutions.
Authors: Buchner Richard , Capewell Stephen G. , Hefter Glenn , May Peter M.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Amorphous Manganese Oxyiodides Exhibiting High Lithium Intercalation Capacity at Higher Current Density.
Authors: Kim J. , Manthiram A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: High Capacity, Temperature‐Stable Lithium Aluminum Manganese Oxide Cathodes for Rechargeable Batteries.
Authors: Chiang Yet‐Ming , Sadoway Donald R. , Jang Young‐Il , Huang Biying , Wang Haifeng
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure of Nonstoichiometric La(Ni,Sn)5+x Alloys and Their Properties as Metal Hydride Electrodes.
Authors: Vogt T. , Reilly J. J. , Johnson J. R. , Adzic G. D. , McBreen J.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Investigation of the Thermal Decomposition of Some Metal‐Substituted Keggin Tungstophosphates.
Authors: Gamelas Jose A. , Couto Fatima A. S. , Trovao M. Cristina N. , Cavaleiro Ana M. V. , Cavaleiro Jose A. S. , de Jesus Julio D. Pedrosa
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Quartzlike Carbon Dioxide: An Optically Nonlinear Extended Solid at High Pressures and Temperatures.
Authors: Iota V. , Yoo C. S. , Cynn H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Structure of Anhydrous Rare‐Earth Perchlorates Ln(ClO4)3 (Ln: La, Ce—Er, Y): Derivatives of the UCl3 Type of Structure.
Authors: Wickleder Mathias S. , Schaefer Wolfgang
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Efficient Asymmetric Protonation of Enolates with Readily Accessible Chiral α‐Sulfinyl Alcohols.
Authors: Asensio Gregorio , Aleman Pedro , Cuenca Ana , Gil Jesus , Medio‐Simon Mercedes
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Palladium‐Mediated Dynamic Kinetic Resolution: Stereoselective Synthesis of Vicinal Diamines.
Authors: Cook Gregory R. , Shanker P. Sathya , Pararajasingham Ketheeswaran
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: N,N‐Phthaloylamino Acids as Chiral Auxiliaries in Asymmetric Mannich‐Type Reactions.
Authors: Mueller Roland , Goesmann Helmut , Waldmann Herbert
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Stereochemistry of a Retro‐Carbolithiation Reaction.
Authors: Hoffmann Reinhard W. , Koberstein Ralf
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.