bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyse interagierender Partikel‐Zell‐Systeme mittels Durchflusszytometrie und mehrdimensionalen Populationsbilanzen
Authors: Rollié S. , Sundmacher K.
Published: June 2010

Zur Bestimmung der Clusterzusammensetzung und ihrer Dynamik in Heteroaggregationsprozessen hat sich die Durchflusszytometrie als wertvolles Messverfahren erwiesen. Sie ermöglicht die unabhängige Auflösung mehrdimensionaler Verteilungen durch eine zuverlässig automatisierte Einzelpartikelanalyse in bisher unerreichtetem Detaillierungsgrad. Bei Untersuchungen binärer und ternärer Partikelgemische lag der Fokus auf elektrostatischen (De‐)Stabilisierungseffekten, die durch die Auswahl geeigneter Partikelspezies und deren Mischungsverhältnis maßgeblich gesteuert werden können. Experimentelle Ergebnisse konnten mit mehrdimensionalen deterministischen Populationsbilanzen simuliert werden. Der physikalisch diskrete Eigenschaftsraum wurde adaptiv mit einer semi‐heuristischen Methode reduziert, so dass nur Eigenschaftskoordinaten mit hohen Partikelkonzentrationen im Modell berücksichtigt werden. Die verwendeten Aggregationskernel basieren auf kolloidchemischen Grundlagen, insbesondere der DLVO‐Theorie, und verknüpfen die Interaktionen auf der Einzelpartikelskala mit dem makroskopischen Verhalten gesamter Partikelpopulationen. Die an partikulären Systemen entwickelten Methoden wurden erfolgreich für eine systematische, modellgestützte Aufklärung präferentieller Aggregationsprozesse in einem ternären System aus Antikörpern und zwei humanen Tumorzelllinien (KARPAS‐299 und U‐937) eingesetzt. Trotz angenommener instantanter Aggregation bei Rezeptor‐Ligand‐Kollisionen, verursacht die geringe Rezeptorkonzentration einen ratenlimitierten Aggregationprozess (RLCA) durch die geringe Oberflächenkonzentration zellulärer Rezeptoren. Populationsbilanzsimulationen mit Kernels, die stark heterogene Oberflächenstukturen der aggregierenden Spezies berücksichtigen (patchy particles), bestätigen die experimentellen Befunde. Die zielgerichtete Verabreichung pharmazeutischer Wirkstoffe mittels Carrierpartikeln an spezifische Zellen unter Minimierung nachteiliger Beeinflussung übriger Zelltypen (targeted drug delivery) ist ein potentielles Anwendungsgebiet dieser Ergebnisse.
Chemieparks: Industrie‐Landschaftspflege à la Germany
Authors: von Zedlitz M.
Published: June 2010

Chemieparks sind ein relativ neues und vor allem typisch deutsches Modell. Sie bieten den dort ansässigen Unternehmen sowie nationalen und internationalen Investoren vielfältige Vorteile: branchen‐optimale Rahmenbedingungen, individuelle Lösungen für Geschäftsmodelle sowie unterschiedliche Dienstleistungen von A wie Abfallentsorgung bis Z wie Zugangskontrolle.
Vom Anlagenverbund zum Entsorgungsnetzwerk
Authors: Brückner J.
Published: June 2010

Eine moderne, nachhaltige Chemieproduktion ist energie‐ und ressourceneffizient. Sie vermeidet Abfälle und schließt Kreisläufe, wo immer es technisch möglich und ökologisch und ökonomisch sinnvoll ist. Mit Anlagenverbünden, einer effizienten Entsorgungsinfrastruktur und einem umfassenden Entsorgungsmanagement unterstützen Chemieparks die Produktionsbetriebe auf ihrem Weg zu einer immer nachhaltigeren Chemieproduktion.
Behördenkommunikation
Authors: Brückner J.
Published: June 2010

Anforderungen und Randbedingungen für den Austausch von Informationen zwischen Betreibern von Industrieanlagen und Behörden erweisen sich zu einem großen Teil als allgemeingültig, unabhängig davon, in welchem Umfeld ein Unternehmen produziert. Die Anforderungen werden anhand der Beispiele der Genehmigungsverfahren, Inspektionen und Betriebsstörungen erläutert.
Chemieparks und ihre Regionen
Authors: Höchst T. , Klingenberg R. , Grieger F. , Gersemann M. , von der Linden B. , Höchst T.
Published: June 2010

Im Windschatten der Globalisierung entstanden in Deutschland regionale Wirtschaftsinitiativen. Trendsetter dieser Entwicklung waren die deutschen Chemieparks. Um die Bedeutung und die Attraktivität der Chemieparks national und international zu stärken, haben sich Chemieparks in Regionalinitiativen zusammengeschlossen. Mitglieder und Vertreter dieser Initiativen stellen sich vor und erläutern ihre Positionen und Ziele.
Synthese und Optimierung von Cellobioselipiden und Mannosylerythritollipiden
Authors: Rupp S. , Zibek S. , Günther M. , Hirth T.
Published: June 2010

Cellobioselipide und Mannosylerythritollipide sind viel versprechende Glykolipide mit Tensid‐ Eigenschaften, die bisher jedoch unzureichend für Anwendungszwecke z. B. als Zusatz von Reinigungs‐ und Körperpflegemitteln charakterisiert wurden. Durch gezielte Anpassung der Kultivierungs‐ und Prozessführungsstrategien wurde die getrennte Herstellung von Cellobioselipiden und Mannosylerythritollipiden aus Ustilago maydis untersucht und optimiert.
Infrastruktur als Erfolgsfaktor für Chemieunternehmen am Standort Deutschland
Authors: Henkel E.
Published: June 2010

Die heutige Chemie‐ und Prozessindustrie in Deutschland ist das Ergebnis tiefgreifender Veränderungen innerhalb der europäischen, politischen und industriellen Landschaft. Hinzu kommt schließlich die Strategie vieler chemischer und pharmazeutischer Unternehmen, sich auf Kernaufgaben zu konzentrieren und weniger zentrale Aufgaben abzustoßen. Diese strukturelle Dynamik hat erheblichen Einfluss auf die chemische Industrie in Deutschland gehabt. Für Investoren, die neue Produktionseinheiten aufbauen wollen, hat sich dank dieses Prozesses ein breites Spektrum an ausdifferenzierten Dienstleistungen ergeben.
Glycosylation Enhances Peptide Hydrophobic Collapse by Impairing Solvation
Authors: Cheng Shanmei , Edwards Scott A. , Jiang Yindi , Gräter Frauke
Published: June 2010

Post‐translational N‐glycosylation of proteins is ubiquitous in eukaryotic cells, and has been shown to influence the thermodynamics of protein collapse and folding. However, the mechanism for this influence is not well understood. All‐atom molecular dynamics simulations are carried out to study the collapse of a peptide linked to a single N‐glycan. The glycan is shown to perturb the local water hydrogen‐bonding network, rendering it less able to solvate the peptide and thus enhancing the hydrophobic contribution to the free energy of collapse. The enhancement of the hydrophobic collapse compensates for the weakened entropic coiling due to the bulky glycan chain and leads to a stronger burial of hydrophobic surface, presumably enhancing folding. This conclusion is reinforced by comparison with coarse‐grained simulations, which contain no explicit solvent and correspondingly exhibit no significant thermodynamic changes on glycosylation.
Retinal patterning by Pax6‐dependent cell adhesion molecules
Authors: Rungger‐Brändle Elisabeth , Ripperger Jürgen A. , Steiner Kurt , Conti Alain , Stieger Ariane , Soltanieh Sahar , Rungger Duri
Published: June 2010

Long‐standing evidence gained from Pax6 mutant embryos pointed to an involvement of Pax6‐dependent cell adhesion molecules in patterning the central nervous system and, in particular, the retina. However, direct evidence for such pathways remained elusive. We here present direct evidence that knockdown of Pax6 expression by morpholino antisense molecules in Xenopus embryos and knockdown of maternal N‐cadherin (mNcad), N‐cadherin (Ncad) and neural cell adhesion molecule (NCAM) produce similar phenotypes. Eye formation is reduced and retinal lamination is heavily disorganized. In Pax6 knockdown embryos, the levels of mRNAs coding for these cell adhesion molecules are markedly reduced. Overexpression of Pax6 efficiently rescues the phenotype of Pax6 knockdown embryos and restores expression of these putative target genes. Rescue of Pax6‐deficiency by the putative target gene mNcad moderately rescues eye formation. The promoters of the genes coding for cell adhesion molecules contain several putative Pax6 binding sites, as determined by computer analysis. Chromatin immunoprecipitation shows that, in embryonic heads, Pax6 binds to promoter regions containing such predicted binding sites. Thus, several cell adhesion molecules are direct target genes of Pax6 and cooperate in retinal patterning. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 764–780, 2010
Stochastic modelling of soil water and plant water stress using cumulant expansion theory
Authors: Kim Sangdan , Han Suhee , Kim Eungseock
Published: June 2010

In this study, a dynamic modelling scheme is presented to derive the probabilistic structure of soil water and plant water stress when subject to stochastic precipitation conditions. The newly developed model has the form of the Fokker–Planck equation, and its applicability as a model for the probabilistic evolution of soil water and plant water stress is investigated under climate change scenarios. This model is based on the cumulant expansion theory, and has the advantage of providing the probabilistic solution in the form of probability distribution function (PDF), from which one can obtain the ensemble average behaviour of the dynamics. The simulation result of soil water confirms that the proposed soil water model can properly reproduce the results obtained from observations, and it also proves that soil water behaves with consistent cycle based on the precipitation pattern. The plant water stress simulation shows two different PDF patterns according to the precipitation. Moreover, with all the simulation results with climate change scenarios, it can be concluded that the future soil water and plant water stress dynamics will differently behave with different climate change scenarios. Copyright © 2010 John Wiley & Sons, Ltd.
Light as a first‐order control on ecosystem structure in a temperate stream
Authors: Julian Jason P. , Seegert Sarah Z. , Powers Stephen M. , Stanley Emily H. , Doyle Martin W.
Published: June 2010

An emerging issue in ecohydrology is the role of light in fluvial ecosystem dynamics. Here, we investigate how photosynthetically active radiation (PAR) influences the hydrogeomorphology and biogeochemistry of a second‐order temperate stream with varying riparian communities from heavily shaded forest sections to unshaded grass sections. First, in‐stream PAR was compared to submerged aquatic macrophyte distributions along a 1·2‐km reach. The effects of macrophytes on water depth, sediment size, sediment volume, organic matter (OM) accumulation and nutrient uptake were then analysed. Compared with forested sites, non‐forested sites had three times more benthic PAR, which resulted in a quadrupling of macrophyte biomass. This greater biomass at non‐forested sites increased water depth, sediment accumulation and the uptake of soluble reactive phosphorous (SRP). Bed sediment size and OM were not significantly different between forested and non‐forested sites. Finally, we used the above relations to estimate biogeochemical differences between a completely forested reach and a non‐forested reach. Compared with a forested reach, the non‐forested reach accumulated almost twice as much bed sediment and retained more than four times as much SRP. Thus, changes in riparian conditions may create a cascade through which shading drives changes in stream habitat, which in turn drives changes in hydrogeomorphology and biogeochemical cycles. Copyright © 2010 John Wiley & Sons, Ltd.
IL‐6: Regulator of Treg/Th17 balance
Authors: Kimura Akihiro , Kishimoto Tadamitsu
Published: June 2010

IL‐6 is a pleiotropic cytokine involved in the physiology of virtually every organ system. Recent studies have demonstrated that IL‐6 has a very important role in regulating the balance between IL‐17‐producing Th17 cells and regulatory T cells (Treg). The two T‐cell subsets play prominent roles in immune functions: Th17 cell is a key player in the pathogenesis of autoimmune diseases and protection against bacterial infections, while Treg functions to restrain excessive effector T‐cell responses. IL‐6 induces the development of Th17 cells from naïve T cells together with TGF‐β; in contrast, IL‐6 inhibits TGF‐β‐induced Treg differentiation. Dysregulation or overproduction of IL‐6 leads to autoimmune diseases such as multiple sclerosis (MS) and rheumatoid arthritis (RA), in which Th17 cells are considered to be the primary cause of pathology. Given the critical role of IL‐6 in altering the balance between Treg and Th17 cells, controlling IL‐6 activities is potentially an effective approach in the treatment of various autoimmune and inflammatory diseases. Here, we review the role of IL‐6 in regulating Th17/Treg balance and describe the critical functions of IL‐6 and Th17 in immunity and immune‐pathology.
Healthier lipid combination as functional ingredient influencing sensory and technological properties of low‐fat frankfurters
Authors: Delgado‐Pando Gonzalo , Cofrades Susana , Ruiz‐Capillas Claudia , Jiménez‐Colmenero Francisco
Published: June 2010

Oil (healthier lipid combination of olive, linseed and fish oils)‐in‐water emulsions stabilized with different protein systems (prepared with sodium caseinate (SC), soy protein isolate (SPI) and microbial transglutaminase (MTG)) were used as pork backfat replacers in low‐fat frankfurters. Composition (proximate analysis and fatty acid profile), sensory analysis and technological (processing and purge losses, texture and colour) properties of frankfurters were analysed as affected by the type of oil‐in‐water emulsion and by chilling storage (2°C, 41 days). Frankfurters produced with oil combinations had lower levels of saturated fatty acids (SFA, 19.3%), similar levels of MUFA (46.9%) and higher levels of PUFA (33.6%) than control frankfurters (all pork fat) (39.3, 49.5 and 10.6%, respectively). PUFA/SFA and n‐6/n‐3 PUFA ratios in control sample were 0.27 and 9.27; in reformulated frankfurters the PUFA/SFA ratio was higher (1.7) and the n‐6/n‐3 PUFA ratio was lower (0.47). In general, frankfurters had good fat and water binding properties. Colour parameters were affected by formulation and storage time. Compared to control sample, frankfurters made with oil‐in‐water emulsions had higher (p<0.05) hardness, springiness and chewiness values. Emulsified oil stabilizing systems did not affect sensory characteristics of frankfurters, and all products were judged as acceptable.
Pd‐PEPPSI Complexes and the Negishi Reaction
Authors: Valente Cory , Belowich Matthew E. , Hadei Niloufar , Organ Michael G.
Published: June 2010

An overview of Pd‐PEPPSI complexes in the Negishi cross‐coupling reaction is presented. Preliminary evaluations of differentially substituted imidazolium salts that generate highly active cross‐coupling catalysts in situ provide the foundation for the development of an air‐ and moisture‐stable NHC‐based precatalyst: Pd‐PEPPSI‐IPr. The application of Pd‐PEPPSI‐IPr in sp3–sp3, sp3–sp2 (and vice versa), and sp2–sp2 Negishi cross‐couplings is reviewed. This allowed the systematic development of Pd‐PEPPSI‐IPent, a more sterically demanding, second‐generation catalyst that outperforms the IPr analogue in a variety of sp2–sp2 Negishi cross‐couplings. General routes for the preparation of organozinc reagents are also examined, and an additives study reveals the probable transmetallating species that is operative in these cross‐couplings. Mechanistic considerations of the Negishi cross‐coupling reaction based on experimental and computational studies are summarized and evaluated.
Practical Synthetic Approach to Chiral Sulfonimides (CSIs) – Chiral Brønsted Acids for Organocatalysis
Authors: He Hao , Chen Ling‐Yan , Wong Wai‐Yeung , Chan Wing‐Hong , Lee Albert W. M.
Published: June 2010

A general approach to the synthesis of optically pure 3,3′‐diaryl chiral sulfonimides (CSIs) from racemic BINOL has been developed. ortho‐Lithiation is directed by the sulfonyl groups, and the resulting dihalides serve as the common precursors for the aryl‐substituted CSIs.
Influence of the Reaction Conditions on the Evolution of the Michael Addition of β‐Keto Sulfones to α,β‐Unsaturated Aldehydes
Authors: Alemán José , Marcos Vanesa , Marzo Leyre , García Ruano José Luis
Published: June 2010

We have studied the influence of different reaction conditions on the conjugated addition of β‐keto sulfones to α,β‐unsaturated aldehydes catalyzed by silyl prolinol ethers. Small changes in the starting material and/or in the experimental protocol are able to produce significant variations in the structures of the final products. The high chemical versatility of the resulting Michael adducts make possible their use in a variety of tandem and one‐pot reactions to afford polysubstituted cyclic products bearing multiple chiral centers.
A simple and efficient method for processing of cell lysates for two‐dimensional gel electrophoresis
Authors: Xavier Tessy , Sreepriya  , Ganesan Trivadi S. , Menon Krishnakumar N.
Published: June 2010

Sample preparation is one of the major issues in 2‐DE for the separation of proteins. Although a 100% representation of cellular proteins onto a 2‐DE is virtually impossible, maximum representation of cellular proteins compared with the original cell lysate is important in the subsequent analysis. We demonstrate that lysis of cells in urea/thiourea solution with subsequent sonication to disrupt the nucleic acids and concentration of the lysate using centri‐con led to enrichment of proteins. The procedure resulted in minimal nucleic acid contamination with better resolution of spots. 2‐DE spot patterns of proteins prepared using urea–thiourea solubilization/centri‐con method to other protein enrichment methods such as phenol/chloroform/isoamyl alcohol extraction, methanol/ammonium acetate precipitation, acetone precipitation and ethanol precipitation were compared. Urea–thiourea solubilization combined with centri‐con method of protein enrichment represented higher number/unique spots particularly in the 50–250 kDa Mr compared with others. Lysis of cells in urea/thiourea from the beginning of lysate preparation preserves the proteins from protease activity due to denaturation of proteases. Thus, we demonstrate that the centri‐con methodology is simple and effective for the preparation of high‐quality sample that can be used for a qualitative representation of cellular proteins on a 2‐DE for proteomic analysis.
Bacterial cytotoxicity of the silver nanoparticle related to physicochemical metrics and agglomeration properties
Authors: Bae Eunjoo , Park Hee-Jin , Lee Jeongjin , Kim Younghun , Yoon Jeyong , Park Kwangsik , Choi Kyunghee , Yi Jongheop
Published: June 2010

Silver particles are used in various consumer products due to their positive effects, which include sterilization and antibacterial properties. However, it has been reported that silver nanoparticles (AgNPs) have strongly acute toxic effects on various cells. Therefore, the cytotoxicity of AgNPs was investigated, using Escherichia coli as a model organism, from the standpoint of three key metrics (ionic ratio, size, and agglomeration) that are the most relevant physicochemical properties. The findings indicated that cytotoxicity is depressed by the agglomeration of AgNPs. The order of toxic sensitivity was as follows: total Ag concentration > ionic ratio > size, the order of which was inversely related to the extent of agglomeration. Environ. Toxicol. Chem. 2010;29:2154–2160. © 2010 SETAC
Complex contaminant exposure in cetaceans: A comparative E-Screen analysis of bottlenose dolphin blubber and mixtures of four persistent organic pollutants
Authors: Yordy Jennifer E. , Mollenhauer Meagan A.M. , Wilson Rachel M. , Wells Randall S. , Hohn Aleta , Sweeney Jay , Schwacke Lori H. , Rowles Teri K. , Kucklick John R. , Peden-Adams Margie M.
Published: June 2010

Cetaceans are federally protected species that are prone to accumulate complex mixtures of persistent organic pollutants (POPs), which individually may exert estrogenic or antiestrogenic effects. In the present study it was assessed whether contaminant mixtures harbored by cetaceans are estrogenic or antiestrogenic using a comparative approach. Interactions of antiestrogenic and estrogenic compounds were first investigated with the E-Screen assay using a mixture of four POPs (dichlorodiphenyldichloroethylene [4,4′-DDE], trans-nonachlor, and polychlorinated biphenyls [PCBs] 138 180) prevalent in cetacean blubber. Estrogenic/antiestrogenic activity was determined for the individual compounds and their binary, tertiary, and quaternary combinations. Significantly different responses were observed for the various POP mixtures, including enhanced estrogenic and antiestrogenic effects and antagonistic interactions. These results were then compared to the concentrations and estrogenic/antiestrogenic activity of contaminant mixtures isolated directly from the blubber of 15 bottlenose dolphins (Tursiops truncatus) collected from five U.S. Atlantic and Gulf of Mexico locations. The lowest observed effect concentrations (LOECs) determined for 4,4′-DDE (20 µmol/L), PCB 138 (20 µmol/L), PCB 180 (21 µmol/L), and trans-nonachlor (3 µmol/L) in the E-Screen were greater than estimated dolphin blood concentrations. Although estimated blood concentrations were below the LOECs, significant estrogenic activity was detected in diluted dolphin blubber from Cape May, NJ and Bermuda. Positive correlations between blubber estrogenicity and select POP concentrations (ΣDDTs, ΣPBDEs, ΣHCB, Σestrogenic PCBs, Σestrogenic POPs) were also observed. Collectively, these results suggest that select bottlenose dolphin populations may be exposed to contaminants that act in concert to exert estrogenic effects at biologically relevant concentrations. These observations do not necessarily provide direct evidence of endocrine disruption; however, they may indicate an environmental source of xenoestrogenic exposure warranting future research. Environ. Toxicol. Chem. 2010;29:2143–2153. © 2010 SETAC
Expression of p53, MDM2, p21, heat shock protein 70, and HPV 16/18 E6 proteins in oral verrucous carcinoma and oral verrucous hyperplasia
Authors: Lin Hung‐Pin , Wang Yi‐Ping , Chiang Chun‐Pin
Published: June 2010

Background

Oral verrucous hyperplasia is a precancerous lesion of oral verrucous carcinoma.

Methods

This study used immunohistochemistry to examine the expression of p53, murine double minute 2 (MDM2), p21, heat shock protein 70 (HSP 70), and human papillomavirus (HPV) 16/18 E6 proteins in 48 oral verrucous carcinoma and 30 oral verrucous hyperplasia samples.

Results

The mean labeling indices of p53, MDM2, p21, HSP 70, and HPV 16/18 E6 proteins in oral verrucous carcinoma samples were 21%, 31%, 7%, 17%, and 0.5%, respectively, and those in oral verrucous hyperplasia samples were 19%, 35%, 11%, 14%, and 0.3%, respectively.

Conclusions

Immunohistochemistry with the above‐cited 5 biomarkers could not help differentiate oral verrucous hyperplasia from oral verrucous carcinoma. The low expression of p21 may partially explain abnormal epithelial overgrowth in both verrucous lesions. The pathogenesis of both verrucous lesions may be at least partially attributed to the overexpression of MDM2 protein and moderate expression of HSP 70 protein in both lesions. © 2010 Wiley Periodicals, Inc. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Therapy for Hdv!
Authors: Taylor John M.
Published: June 2010

Hepatitis delta virus (HDV) can dramatically worsen liver disease in patients coinfected with hepatitis B virus (HBV). No effective medical therapy exists for HDV. The HDV envelope requires HBV surface antigen proteins provided by HBV. Once inside a cell, however, HDV can replicate its genome in the absence of any HBV gene products. In vitro, HDV virion assembly is critically dependent on prenyl lipid modification, or prenylation, of its nucleocapsid–like protein large delta antigen. To overcome limitations of current animal models and to test the hypothesis that pharmacologic prenylation inhibition can prevent the production of HDV virions in vivo, we established a convenient mouse–based model of HDV infection capable of yielding viremia. Such mice were then treated with the prenylation inhibitors FTI–277 and FTI–2153. Both agents were highly effective at clearing HDV viremia. As expected, HDV inhibition exhibited duration–of–treatment dependence. These results provide the first preclinical data supporting the in vivo efficacy of prenylation inhibition as a novel antiviral therapy with potential application to HDV and a wide variety of other viruses.
A New Survival Trick of Hepatitis C Virus: Blocking the Activation of Interferon Regulatory Factor–3
Authors: Heim Markus H.
Published: June 2010

Persistent infections with hepatitis C virus (HCV) are likely to depend on viral inhibition of host defenses. We show that the HCV NS3/4A serine protease blocks the phosphorylation and effector action of interferon regulatory factor–3 (IRF–3), a key cellular antiviral signaling molecule. Disruption of NS3/4A protease function by mutation or a ketoamide peptidomimetic inhibitor relieved this blockade and restored IRF–3 phosphorylation after cellular challenge with an unrelated virus. Furthermore, dominant–negative or constitutively active IRF–3 mutants, respectively, enhanced or suppressed HCV RNA replication in hepatoma cells. Thus, the NS3/4A protease represents a dual therapeutic target, the inhibition of which may both block viral replication and restore IRF–3 control of HCV infection.
Multi‐photon resonance enhancement of third harmonic generation in human oxyhemoglobin and deoxyhemoglobin
Authors: Chang Chieh‐Feng , Yu Che‐Hang , Sun Chi‐Kuang
Published: June 2010

Cancer cells require excessive oxygen and nutrition to support their rapid growth, so angiogenesis and decrease of blood oxygen are often associated with areas of cancer development. Current technologies for blood oxygen measurement, however, do not possess high spatial resolution and therefore cannot be used to detect small tumors in their early stage. In this paper, we studied the third harmonic generation (THG) spectra of oxy‐ and deoxyhemoglobin in the 1170–1365 nm region, which is strongly influenced by the multi‐photon resonance effect, especially around the Soret transition band. Our spectroscopic results thus indicate the high potential of THG spectroscopic microscopy for oxygen depletion level measurement of a single red blood cell in vivo. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rubber‐toughening of dimethacrylate dental composite resin
Authors: Lee Valerie A. , Cardenas H. Lee , Rawls H. Ralph
Published: June 2010

Dimethacrylate dental composite resins exhibit inherently low toughness. Toughening of these materials may reduce the incidence of marginal and bulk fracture of composite restorations.

Objective: To determine if dimethacrylate dental restorative materials can be rubber‐toughened, and if so, to identify a possible mechanism.

Methods: A filler composed of aggregates of polybutadiene/silica as well as irregularly‐shaped silica slabs was produced by mixing silica with polybutadiene in dichloromethane. The dried filler was subsequently ground and sieved to <25 μm. Polybutadiene/silica ratios were varied from 0:1 (control) to 0.5:1. EDAX analysis verified the composition of the complex filler. Filler was added to a bis‐GMA/bis‐EMA/TEGDMA resin system and fractured in three‐point bend test mode at a crosshead speed of 1 mm/min. In addition, 1 bar was fractured at a crosshead speed of 0.001 mm/min to identify a possible mechanism for toughening.

Results: In specimens fractured at 1 mm/min, flexural modulus is increased or maintained and flexural strength and energy to break increase as the amount of polybutadiene in the aggregates increases. Cavitation of high‐rubber‐containing aggregates is demonstrated. In the one specimen fractured at 0.001 mm/min, a marked increase in size of high‐rubber‐containing aggregates along with severe shear damage in the surrounding matrix is shown, suggesting that cavitation with subsequent absorption of energy during shear yielding is the likely mechanism behind the increase in energy to break in bars fractured at 1 mm/min.

Significance: These results indicate that dimethacrylate dental composite materials can be rubber toughened, which may potentially reduce marginal and bulk fractures of composite restorations, and consequently extend their service lifetime. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Reduction of hexavalent chromium by Bacillus sp. isolated from chromite mine soils and characterization of reduced product
Authors: Dhal Biswaranjan , Thatoi Hrudayanath , Das Nigamananda , Pandey Bansi Dhar
Published: June 2010

BACKGROUND: The reduction of highly mobile and toxic hexavalent chromium by bacterial strains is considered to be a viable alternative to reduce Cr(VI) contamination, in soils and water bodies, emanating from the overburden dumps of chromite ores and mine drainage. The present study reports the isolation of Cr(VI) resistant bacterial strains from an Indian chromite mine soil and their potential use in reduction of hexavalent chromium.

RESULTS: Among the isolates, a bacterial strain (CSB‐4) was identified as Bacillus sp. based on standard biochemical tests and partial 16SrRNA gene sequencing, which was tolerant to as high as 2000 mg L−1 Cr(VI) concentration. The strain was capable of reducing Cr(VI) to Cr(III) in different growth media. Under the optimized conditions pH ∼7.0, 100 mg L−1 Cr(VI), 35 °C temperature and stirring speed 100 rpm, CSB‐4 reduced more than 90% of Cr(VI) in 144 h. The time course reduction data fitted well an exponential rate equation yielding rate constants in the range 3.22 × 10−2 to 6.5 × 10−3 h−1 for Cr(VI) concentration of 10–500 mg L−1. The activation energy derived from temperature dependence rate constants between 25 and 35 °C was found to be 99 kJ mol−1. The characterization of reduced product associated with bacterial cells by SEM‐EDS, FT‐IR and XRD was also reported.

CONCLUSION: Reasonably high tolerance and reduction ability of indigenous Bacillus sp. (CSB‐4) for Cr(VI) under a wide range of experimental conditions show promise for its possible use in reclamation of chromite ore mine areas including soils and water bodies. Copyright © 2010 Society of Chemical Industry
Development of an efficient electroflocculation technology integrated with dispersed‐air flotation for harvesting microalgae
Authors: Xu Ling , Wang Feng , Li Hua‐Zhong , Hu Zan‐Min , Guo Chen , Liu Chun‐Zhao
Published: June 2010

BACKGROUND: Various methods, including centrifugation, filtration, electroflocculation, flocculation and flotation, have been developed for harvesting microalgae. However, some economic or technical problems still remain with current methods for algal recovery, such as high capital, energy and running costs, flocculant toxicity or low separation efficiency. Therefore, there is great interest in developing new efficient approaches for harvesting microalgae.

RESULT: An efficient electroflocculation method integrated with dispersed‐air flotation has been developed for harvesting Botryococcus braunii. The recovery efficiency of B. braunii reached 93.6% after 30 min using an electroflocculation process. Microalgae recovery was improved significantly when the electroflocculation process was integrated with dispersed‐air flotation; the recovery efficiency of B. braunii reached 98.9% after 14 min.

CONCLUSION: The present work demonstrated that electroflocculation integrated with dispersed‐air flotation is a promising method suitable for microalgae harvesting. The strategic air supply obviously shortened the algal recovery time in the process of electroflocculation due to facilitating algal aggregation and flotation to the solution surface. Copyright © 2010 Society of Chemical Industry
Synthesis of Sphingosine Relatives, XVII! Synthesis of (2S,2' R,3R,3' E,4E,8E)‐1‐O‐(β‐D‐Glucopyranosyl)‐N‐(2'‐hydroxy‐3'‐octadecenoyl)‐9‐methyl‐4,8‐sphingadienine (Pen II), the Major Cerebroside Isolated from Penicillium funiculosum as the Fruiting‐Inducer Against Schizophyllum commune
Authors: Mori Kenji , Uenishi Keiji
Published: June 2010

Pen II [(2S,2' R,3R,3' E,4E,8E)‐1‐O‐(β‐D‐glucopyranosyl)‐N‐(2'‐hydroxy‐3'‐octadecenoyl)‐9‐methyl‐4,8‐sphingadienine], the major component of the cerebrosides isolated from Penicillium funiculosum A‐1 as the fruiting inducer against Schizophyllum commune, was synthesized by starting from D‐glucose, L‐serine, (2R,3E)‐2‐(tert‐butyldiphenylsilyloxy)‐3‐octadecenoic acid, and (E)‐6‐methyl‐5‐pentadecen‐1‐yne.
Diastereo‐ and Enantioselective Synthesis of 1,2‐Amino Alcohols and Protected α‐Hydroxy Aldehydes from Glycol Aldehyde Hydrazones
Authors: Enders Dieter , Reinhold Ulrich
Published: June 2010

Starting from chiral glycol aldehyde hydrazones (S)‐2, we prepared differently protected α‐hydroxy aldehydes (R)‐ or (S)‐4 as well as N‐acetyl‐protected 1,2‐amino alcohols (R)‐11 in high enantiomeric excesses via azaenolate α‐alkylation or nucleophilic 1,2‐addition to the CN double bond. The successive introduction of two vicinal stereogenic centres opens a new, flexible syn‐diastereo‐ and enantioselective route to functionalised, N‐acetyl‐protected, vicinal amino alcohols (R,R)‐13, which was demonstrated in the case of the γ‐amino‐β‐hydroxycarboxylic acid statin (R,R)‐15 and its analogues B.
Antibiotics from Gliding Bacteria, LXXIII Indole and Quinoline Derivatives as Metabolites of Tryptophan in Myxobacteria
Authors: Böhlendorf Bettina , Bedorf Norbert , Jansen Rolf , Trowitzsch‐Kienast Wolfram , Höfle Gerhard , Forche Edgar , Gerth Klaus , Irschik Herbert , Kunze Brigitte , Reichenbach Hans
Published: June 2010

Two groups of 3‐substituted indole 1, 6–9 as well as 4‐substituted quinoline derivatives 2–5 and harman (10) were isolated from various species and genera of myxobacteria. They were identified by their spectroscopic data. Some of the metabolites show moderate antifungal activity. Their biosynthetic origin in myxobacteria was demonstrated for 1, 2, and 3 by incorporation of L‐[1'‐14C]tryptophan.
Electroorganic Synthesis, 62!! Anodic Heterocoupling (Mixed Kolbe Electrolysis) of Carbohydrate Carboxylic Acids with Alkanoic Acids to C‐Glycosides
Authors: Harenbrock Michael , Matzeit Agnes , Schäfer Hans J.
Published: June 2010

2‐Deoxy carbohydrate carboxylic acids 1–3 were prepared from glucal 4, acetobromoglucose 5, and D‐galactose (7), respectively. The acids 1–3 were electrolyzed with different coacids at controlled current in methanol at platinum electrodes in an undivided cell to afford C‐glycosides as heterocoupling products in 46–70% yield. Compound 28, obtained by deacylation of 17, has a critical micelle concentration (cmc) of 2.4 mM, which is about 2.5 times lower than that of the corresponding O‐glycoside 29. Compound 28 forms liquid crystals with a smectic A phase in the range between 96 and 190°C, which is twice as large as that of 29. Compounds 31 and 32, obtained by deprotection of 23 and 24, respectively, also exhibit liquid crystalline behavior.
Enantioselective Diels‐Alder Reactions: NMR Spectroscopy of a Chiral Titanium Lewis Acid under High Pressure
Authors: Tietze Lutz F. , Ott Christian , Frey Urban
Published: June 2010

1H‐NMR investigations of the temperature and pressure dependence of the equilibrium of the reaction of the tartaric acid derivative 7 with titanium dichloride diisopropoxide (8) to give the chiral Lewis acid 9 show that increasing pressure and temperature shift the equilibrium to the achiral Lewis acid 8. The observed decrease in enantioselectivity of the cycloaddition reaction of isoprene (3) with 3‐crotonyl‐1,3‐oxazolidin‐2‐one (4) in the presence of 7 and 8 under high pressure may therefore be attributed at least in part to the unfavorable influence of pressure on the formation of 9.
Synthesis of (1S,5S)‐4,5‐Dihydro‐1,5‐epoxy‐1H‐2‐benzoxocin‐6(3H)‐one from (S)‐Malic Acid Derivatives
Authors: Wünsch Bernhard , Diekmann Heike
Published: June 2010

The homochiral 1,3‐dioxanes 8a–e with a 2‐bromophenyl substituent in position 2 and an electrophilic group in position 4 were stereo‐ and regioselectively prepared from the (S)‐malic acid derivatives 6a, 6b, 11, and 14. Attempts to prepare the tricycles 5a–c by connecting the 2‐phenyl substituent with the electrophilic groups in position 4 of 8a–e in a Parham cyclization across the 1,3‐dioxane ring failed. The synthesis of the tricyclic title ketone 5a succeeded, however, by addition of the lithiated benzaldehyde acetal 7c to the protected α‐hydroxylactone 10b and subsequent treatment of the intermediate ketone 23 with acid. The acid hydrolysis of the alcohol 26, which was obtained by addition of 7c to the protected dihydroxy aldehyde 25b, followed by oxidation of the resulting alcohols 27a and b represent a second possibility for the preparation of the tricyclic ketone 5a.
Lintenolides C–E: Unusual Antifeedant Sesterterpenes Isolated from the Marine Sponge Cacospongia cf. linteiformis
Authors: Carotenuto Alfonso , Fattorusso Ernesto , Magno Silvana , Mayol Luciano , Lanzotti Virginia
Published: June 2010

In addition to the previously described lintenolides A and B (3a, b and 4a, b), the marine sponge Cacospongia cf. linteiformis was also found to produce the three new lintenolides C (7a, b), D (8a, b) and E (9a, b), all possessing the same highly antifeedant activity previously found in lintenolides A and B. The stereostructures of the metabolites were mainly elucidated by extensive NMR studies.
Ring Opening Reactions of Iminoaziridines and Aminoazirinium Ions. Is Electrocyclic Ring Opening of 2H‐Azirinium Ions a Myth?
Authors: Quast Helmut , Aldenkortt Sven , Freudenreich Bernd , Schäfer Peter , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg , Würthwein Ernst‐Ulrich
Published: June 2010

Treatment of the 3,3‐dimethyl‐2‐iminoaziridine 7 with hydrogen bromide yields similar amounts of the α‐bromo amidine 10a · HBr and the α,β‐unsaturated amidinium bromide 11. Ring opening reactions of the 3‐tert‐butyl‐2‐iminoaziridines 8 by nucleophiles (potassium methoxide, Pirkle's alcohol 13, and 4‐nitrophenol) are sluggish affording the α‐amino imidates 12, 14, and 15, respectively. Compound 15a isomerises via the Meisenheimer‐type intermediate 16 to furnish the α‐amino amide 17. Methyl triflate converts (R)‐8 into the 2‐tert‐butyl‐3‐amino‐2H‐azirinium triflates (R)‐18 which do not undergo racemisation as shown after hydrolysis to yield the α‐amino amides (R)‐20. In a similar sequence, (R)‐8a and b are converted into the α‐amino amides (R)‐26 by the action of hydrogen halides or 4‐toluenesulfonic acid hydrate followed by hydrolysis of the intermediate imidoyl derivatives (R)‐24. Retention of configuration is observed after treatment of (R)‐8a with hydrogen chloride and of (R)‐8b with hydrogen bromide. Some racemisation found in the other cases is supposed to involve (R)‐24 but not the aminoazirinium ions (R)‐8 · HX. In a side reaction, 8a and b decompose into methyl isocyanide (22) and the imines 23 at low temperatures, probably under general acid catalysis. The results are not consistent with the hypothesis of an electrocyclic ring opening of 3‐amino‐2H‐azirinium ions to afford 2‐amino‐1‐azaallyl cations (= α‐imino carbocations). – The heat of protonation of the parent compounds (E)‐27, (Z)‐27, 30 and the structures and energies of the resulting cations (E)‐28, (Z)‐28, 29, and 31 were calculated by ab initio methods. Complete geometry optimisations were performed with the RHF/6‐31 + G** basis set. Energies were calculated on the RHF, MP2, MP4SDTQ, and CCSD(T) levels. According to the geometric parameters, the amidine delocalisation of the free bases is abondened in the cations (E)‐28, (Z)‐28, and 31 while it is considerably strengthened in 29. In accord with these geometric changes, 29 is by far the most stable protonated species followed by (E)‐ and (Z)‐28. Azirine 31 is much higher in energy. The calculated difference in (gas phase) basicity between the two nitrogen atoms of iminoaziridines appears to exclude the ring‐protonated cations as intermediates also for reactions in solution.
Two New Guaiadiene Derivatives Isolated from Thuja occidentalis L. Wood Oil
Authors: Weyerstahl Peter , Marschall Helga , Collin Guy
Published: June 2010

Two new guaiadiene derivatives, the ether 9α, 11‐epoxy‐1βH,5αH,7βH‐guaia‐3,10(14)‐diene (4) and the corresponding alcohol 1βH,5αH,7βH‐guaia‐3,10(14)‐dien‐11‐ol (8) were isolated from the essential oil from the heartwood of Thuja occidentalis L. Their structures were elucidated by 1H‐ and 13C‐NMR spectroscopy (COSY, NOED).
Synthesis of (±)‐Azaascorbic Acid
Authors: Stachel Hans‐Dietrich , Zeitler Klaus , Dick Stefan
Published: June 2010

The synthesis of the hitherto unknown aza analog of ascorbic acid (±)‐10a is described. Aldol type reaction of the tetramic acid derivative 4 with tert‐butyldimethylsilyloxy acetaldehyde furnished a mixture of the aldol (±)‐5b and the diastereomeric O‐Boc protected aldols (±)‐6a and (±)‐6b. By X‐ray structural analysis the major reaction product was shown to be the threo isomer 6a. Desilylation of 6a led to the alcohol 7. Removal of the remaining protective groups yielded racemic azaascorbic acid 10a. Similar deprotection of the aldol 5b led only to impure azaisoascorbic acid (±)‐10b which was characterized as the dimethyl ether 12b.
Intramolecular [2 + 2] Photocycloaddition of 2‐Allylindane‐1‐thiones
Authors: Nishio Takehiko , Okuda Norikazu , Kashima Choji
Published: June 2010

The photochemical reactions of indane‐1‐thiones 4 were examined. Irradiation of indane‐1‐thiones 4c–d bearing δ‐hydrogen atoms in the side chain gave cyclic thiol derivatives 5c–d via δ‐hydrogen atom abstraction by the excited thiocarbonyl sulfur. Irradiation of 2‐allylindane‐1‐thiones 4e–h afforded the multifused thietanes 7e–h by intramolecular [2 + 2] cycloaddition between CS and CC bonds.
Synthesis of Thione Analogues of Monobactams
Authors: Nieschalk Jens , Schaumann Ernst
Published: June 2010

Optically active β‐lactams 4 were treated with Lawesson's reagent (2) or Davy's reagent (3) to give the β‐thiolactams 5. Demethylation of 5 by reduction with dissolved metal gave the 1‐unsubstituted 2‐azetidinethiones 6 which were sulfonated and Boc‐deprotected to provide (3S)‐amino‐2‐thiomonobactamic acids 8. The side chain on nitrogen was introduced by using 1‐hydroxybenzotriazole‐activated acids 9. Deprotection of functional groups in the side chain yielded the β‐thiolactam analogues 11a, 11b of SQ 81,377 and aztreonam (1). These compounds were found to be weakly active against a range of Gram‐negative bacteria.
Synthesis of (—)‐Malyngolide
Authors: Flörke Holger , Schaumann Ernst
Published: June 2010

δ‐Lactone (–)‐malyngolide (1) was synthesized by starting from the optically active epoxide 5. Coupling of derivative 3 with propargyl anion 11 and subsequent metal‐catalyzed methylation of the triple bond provided 14 incorporating all the carbon atoms of 1. Cyclization to the acetal 16 was achieved via the epoxidation product 15. Adjustment of the oxidation state and removal of protective groups complete the synthesis of 1.
Pseudosugars, 36. Synthesis of Methyl 5a′‐Carbamaltoses Linked by Imino, Ether and Sulfide Bridges and Unsaturated Derivatives Thereof
Authors: Tsunoda Hidetoshi , Sasaki Shin‐Ichi , Furuya Takashi , Ogawa Seiichiro
Published: June 2010

Methyl 5a′‐carbamaltoses linked by imino, ether, and sulfide bridges were synthesized by coupling of an amino carbasugar with a sugar epoxide and of the carbasugar epoxide with the oxide anion or thioacetate derived from sugar derivatives. Their unsaturated derivatives related to a potent α‐glucosidase inhibitor, methyl acarviosin, were also synthesized. Moderate inhibitory activity against baker's yeast α‐glucosidase was observed only for the imino‐linked compounds 2 and 5.
1‐Halo‐1‐acceptor‐/1,1‐diacceptor‐substituted Allenes, 9. Functionalized Allenes, Haloallenes, and Bisallenes via [2,3]/[3,3]‐Sigmatropic Rearrangements and Their Reactivity
Authors: Saalfrank Rolf W. , Welch Andreas , Haubner Martin , Bauer Udo
Published: June 2010

Reaction of carbonyl compounds 1 with trimethylsilylacetylene 2 leads to the alkynols 3, which are excellent precursors of acceptor‐substituted allenes. Compound 3 reacts with carbamoyl chloride 4, diethyl chlorophosphate 6, or hypohalite 8 to give the substituted alkynols 5, 7, 9, Reaction of 9 with sulfinyl chloride 10 leads to the sulfinic esters 11, which on heating undergo a [2,3]‐sigmatropic shift to yield the halosulfonyl allenes 12. In the same manner the reaction of 7 and 9 with chlorophosphanes 13 or sulfenyl chlorides 15 gives rise to the generation of the phosphoryl allenes 14 and the haloallenyl sulfoxides 16, respectively. Alkynyl ketene acetal intermediates 18 are formed by starting from the alkynols 9 and orthoesters 17. Spontaneous [3,3]‐sigmatropic rearrangement of 18 gives the haloallenyl esters 19. Reaction of alkynols 5 with sulfur dichloride leads to the alkynylsulfinyl esters 20, which on heating rearrange to the bisallenyl sulfones 21. Pyrolysis of 21 yields the thiophene 1,1‐dioxides 22. Bisphosphorylbisallene 24 is synthesized from hexadiyndiol 23 by reaction with chlorodiethoxyphosphite. Halophosphoryl allenes 14 react with bromine to yield the oxaphospholenes 25 by cyclization and subsequent elimination of ethanol, or oxaphospholenes 26, if no appropriate leaving group is present in the molecule. Sulfonyl‐1,3‐dienes 27 can be synthesized by reaction of halosulfonylallenes 12 with bromine, followed by elimination of HBr. Haloallenyl ester 19a is converted in a non‐generalizable reaction with bromine into the tribromo‐3 6‐dihydro‐2‐pyranone 30.
Efficient Synthesis of 1,4‐Thiazepin‐3‐one Derivatives and Their Ring Transformations
Authors: Zaleska Barbara , Cież Dariusz , Grochowski Jacek , Serda Pawel , Winnik Witold
Published: June 2010

A new one‐pot synthesis of title compounds 2 by reaction of β‐aminothiocinnamic acid anilides 1 with α‐haloacid halides is described. The ring of 1,4‐thiazepine 2 in basic medium undergoes transformation to thiazolidin‐4‐ones 5.
Pronounced Electronic Effect of Allylic Amino Groups on the π‐Facial Stereoselectivity and Reactivity of the Iodoetherification of N‐Substituted 3‐Amino‐4‐penten‐1‐ols
Authors: Tamaru Yoshinao , Harayama Hiroto , Bando Takashi , Nagaoka Hirooki , Yoshida Zen‐Ichi
Published: June 2010

The iodoetherification of N‐substituted 3‐amino‐4‐penten‐1‐ol (1) [I2 and NaHCO3 (2 equivalents each) in ether/H2O at 0°C], providin the mixtures of N‐substituted cis‐ and trans‐ 3‐amino‐2‐iodomethyltetrahydrofurans (9), displayed diastereoselectivity which was found to correlate with the Taft σ* constants of the N‐substitutents (SO2CF3, SO2Me, SO2‐P‐Tol, COPh, COMe): log(cis‐9/trans‐9) = 0.616σ* – 1.67 (r = 0.997). the 2‐methyl‐substituted derivatives of 1 exhibit larger ρ values, while for the 4‐methyl derivative of 1 is approximately zero, Iodoetherification of a variety of N‐tosyl (σ* = 3.32) 1‐ and 2‐substituted derivatives of 1 afforded the corresponding cis isomers with 70 – >95% selectivities, while that of the N‐benzoyl (σ* = 2.20) derivatives furnished the trans isomeres with 70–80% selectivities. These results are interpreted in terms of a πC(4)–C(5)‐σ*C(3)–N interaction of conformer II. The N‐CO2R (R = Et, t‐Bu) and N‐SO2NMe2 derivatives of 1 display anomalously high cis selectivities.
Additions of Silyl Enol Ethers to β‐Formyl Esters – a Chelate‐controlled Synthesis of the Pheromone (+)‐Eldanolide
Authors: Angert Hubert , Czerwonka Regina , Reißig Hans‐Ulrich
Published: June 2010

Chelate‐controlled Mukaiyama reaction of silyl enol ethers 2a, 2b, 2c, and 2d with β‐formylcarboxylate 1 in the presence of TiCl4 provided γ‐lactones 3a, 3b, 3c, and 3d in very good yields and with good to excellent trans selectivities. The use of BF3, SnCl4, and SnBr4 as Lewis acids afforded 3a with moderate cis selectivity thus excluding chelate control. Starting with (S)‐1 TiCl4‐promoted reaction with 2b, we obtained optically active γ‐lactone 3b which was efficiently converted into the pheromone (+)‐eldanolide in two steps. The enantiomeric excess of 87% proved that the sequence proceeds without detectable racemization.
Total synthesis of Aklanonic Acid and Derivatives by Baker–Venkataraman Rearrangement
Authors: Krohn Karsten , Roemer Ernst , Top Michael
Published: June 2010

Aklanonic acid (1) and the derivatives 2 and 15a–f were prepared by Baker‐Venkataraman rearrangement of the corresponding ortho‐acetyl anthraquinone esters 13a–e and 14 using lithium hydride in THF.