bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and properties of polyurethane/benzyl amylose semi‐interpenetrating networks
Authors: Cao Xiaodong , Tao Yongzhen , Lucia Lucian A. , Zhang Lina
Published: December 2009

A series of semi‐interpenetrating polymer networks (semi‐IPNs) films were prepared from 20 wt % of benzyl amylose (BA) of different Mw and castor oil‐based polyurethane (PU) in N,N‐dimethylformamide (DMF). The weight‐average molecular weight (Mw), and radii of gyration (z1/2) of benzyl amylose were determined by laser scattering measurement, and the results suggested BA was in a compact coil conformation in DMF. Furthermore, the properties and miscibility of the polyurethane/benzyl amylose (PUBA) films were studied by scanning electronic microscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, ultraviolet–visible spectrophotometer, and tensile testing. The PUBA films possessed much higher optical transmittance and tensile strength than the pure PU film regardless of the molecular weight of BA, but lower values of elongation at break were observed. With decreasing of the BA Mw from 9.24 × 105 to 2.69 × 105, interestingly, the elongation at break of the films increased from 135 to 326%. This might be ascribed to the decrease of crosslinking density of PU networks and the enhancement in freedom of the molecular motion. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The surface modification of medical polyurethane to improve the hydrophilicity and lubricity: The effect of pretreatment
Authors: Zhou Xuefeng , Zhang Tianzhu , Jiang Xiaoli , Gu Ning
Published: December 2009

The medical polyurethane (PU) film was grafted with poly(acrylic acid) (PAA) to improve the hydrophilic and lubricious properties. The influences of pretreatment by ozone or potassium peroxydisulfate on themorphologies of PU films and grafting results were systematically investigated. The grafted PU films were characterized using attenuated total reflection Fourier transformed infrared spectroscopy (ATR‐FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and gel permeation chromatography (GPC). The hydrophilic and lubricious properties were evaluated by water contact angle and friction coefficient, respectively. The results showed that PAA could be grafted firmly on PU activated by both ozone and potassium peroxydisulfate, and the PAA‐grafted PU showed good hydrophilic and lubricious performance. More importantly, the PAA‐grafted PU films with the pretreatment of ozone were better in surface roughness, hydrophilicty and lubricity, compared to those with the pretreatment of potassium peroxydisulfate. Hence, surface ozonation could be a better choice for the pretreatment of medical polymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Performance of fibers embedded in a cementitious matrix
Authors: Pakravan H. R. , Jamshidi M. , Latifi M.
Published: December 2009

Reinforcement of cementitious materials with short fibers has been proved to be an economical and effective way to convert these brittle materials to ductile products. Many fibers with different geometries have been used as reinforcement materials. Fibers bonding to cementitious materials play an important role in mechanical performance of these composites. This article describes the performance of (homemade) fibers as reinforcement in cement‐based materials by investigation on bonding characteristic of fiber to cement matrix. To this end, the fibers (glass, polypropylene, polyacrylonitrile (PAN), and high strength nylon 66 (N66)) are characterized using microscopy analysis, tensile strength, and alkali attack tests. The fibers embedded in the cement matrix, then, pulled‐out to evaluate their bonding to cementitious materials. SEM analysis is used to study fiber/cement interfacial transition zone. The results show that PAN fibers have the advantages of preparing for cementitious reinforcement. It was found that the reinforcing efficiency of fibers‐reinforced cementitious composites was strongly depending on interfacial contact area in fiber/matrix interface and chemical/physical properties of fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of crystallinity on enthalpy recovery peaks and cold‐crystallization peaks in PET via TMDSC and DMA studies
Authors: Shieh Yeong‐Tarng , Lin Yu‐Sheng , Twu Yawo‐Kuo , Tsai Hong‐Bing , Lin Rong‐Hsien
Published: December 2009

Poly(ethylene terephthalate) (PET) sheets of different crystallinity were obtained by annealing the amorphous PET (aPET) sheets at 110°C for various times. The peaks of enthalpy recovery and double cold‐crystallization in the annealed aPET samples with different crystallinity were investigated by a temperature‐modulated differential scanning calorimeter (TMDSC) and a dynamic mechanical analyzer (DMA). The enthalpy recovery peak around the glass transition temperature was pronounced in TMDSC nonreversing heat flow curves and was found to shift to higher temperatures with higher degrees of crystallinity. The magnitudes of the enthalpy recovery peaks were found to increase with annealing times for samples annealed ≤30 min but to decrease with annealing times for samples annealed ≥40 min. The nonreversing curves also found that the samples annealed short times (≤40 min) having low crystallinity exhibited double cold‐crystallization peaks (or a major peak with a shoulder) in the region of 108–130°C. For samples annealed long times (≥50 min), the cold‐crystallization peaks were reduced to one small peak or disappeared because of high crystallinity in these samples. The double cold‐crystallization exotherms in samples of low crystallinity could be attributed to the superposition of the melting of crystals, formed by the annealing pretreatments, and the cold‐crystallizations occurring during TMDSC heating. The ongoing crystallization after the cold crystallization was clearly seen in the TMDSC nonreversing heat flow curves. DMA data agreed with TMDSC data on the origin of the double cold‐crystallization peaks. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Zur Ermittlung der Verformungen von Stahlbetonbauteilen im Grenzzustand der Gebrauchstauglichkeit
Authors: Duţulescu Eugen
Published: December 2009

In Beton‐ und Stahlbetonbau 104, Heft 8, wurden die für die Ermittlung der Verformungen von Stahlbetonbauteilen benötigte Normalkraft‐mittlere Dehnungslinie, bzw. Biegemoment‐mittlere Krümmungslinie erläutert. Ein Rechenmodell und ein dazugehöriges Näherungsverfahren sowie deren praktische Anwendungen werden hier vorgestellt. Abschließend wird ein Vorgehen zur Vordimensionierung mit begleitenden Hilfsmitteln dargestellt.

About the Calculation of Displacements of Reinforced Concrete Members in the Servicebility Limit State

In Beton‐ und Stahlbetonbau 104, issue 8, the determination of axial tensile force – average strain, respectively bending moment – average curvature diagrams, in order to calculate the displacements of reinforced concrete members, were explained. A calculation model for the deformations, an approximation of it, and their practical applications are explained. Finally, a method for preliminary dimensioning with accompanying diagrams and tables is presented.
Erhöhung der Verbundtragfähigkeit von aufgeklebten CFK‐ oder Stahl‐Lamellen auf Stahlbetonkonstruktionen durch Bügelumschließungen
Authors: Husemann Ulf , Budelmann Harald
Published: December 2009

Bei Bauteilverstärkungen mit CFK‐Lamellen ist nach geltender Zulassung das Lamellenende durch eine äußere Umschließung durch Stahlbügel oder CF‐Gelege gegen eine Lamellenentkopplung (LEK) zu sichern. Durch die Entkopplungsbehinderung der Umschließung wird bei beginnender LEK ein passiver (selbstinduzierter) Anpressdruck aufgebaut, der eine traglaststeigernde Wirkung hat. In einem durch die DFG geförderten Forschungsvorhaben wurde die Traglaststeigerung durch unterschiedliche Umschließungsmaterialien und ‐geometrien untersucht und beschrieben sowie für die Bemessung ein Ingenieurmodell entwickelt. Anders als bei einbetonierter Bewehrung tritt bei einer Lamellenentkopplung sowohl eine Längs‐ als auch eine Querverschiebung der Lamelle auf, verursacht durch die anhaftenden Zuschlagskörner in der Klebstofffuge. Wird die abhebende Verschiebung der Lamelle durch Umschließungsbügel behindert, baut sich der passive Anpressdruck auf, was zu einer Steigerung der Lamellenzugkraft infolge der erhöhten Reibung im Riss führt. Es konnte ein direkter Zusammenhang zwischen dem Anpressdruck FAPund der Lamellenzugkraft Flgefunden und abgebildet werden.

Increase of the Bond Capacitiy of Externally Bonded CFRPor Steel‐plates on RC‐Structures as the Result of External Enclosures

Strengthening of concrete structures with externally bonded CFRP‐ or steel‐plates has become a well established strengthening method in many countries. In Germany building authority approvals demand that the end of a plate has to be provided by a glued external enclosure. Glued enclosures are primarily needed in order to increase the shear force capacity of a RC member. It is known, that a transverse enclosure of longitudinal CFRP‐plates has a positive effect on the buckling load of the latter, which is yet completely unknown. The aim of this work is to assess the increase of the buckling load caused by the enclosure. In the paper the dependency between the so‐called self‐induced contact pressure of an external enclosure with steel frames or laminated carbon fiber sheets and the longitudinal force of the CFRP‐ or steel‐plate is shown. The self‐induced contact pressure is the result of the vertical lifting of the plate towards the external enclosure due to the beginning of plate's debonding process. The test results show, that the increase of the plate‐force depends on the type and size of the external enclosure. In some tests up to twice of the ultimate load was optained. An engineering model is presented to take into consideration the effect for dimensioning.
An Expeditious Multigram‐Scale Synthesis of Lysine Dendrigraft (DGL) Polymers by Aqueous N‐Carboxyanhydride Polycondensation
Authors: Collet Hélène , Souaid Eddy , Cottet Hervé , Deratani André , Boiteau Laurent , Dessalces Guy , Rossi Jean‐Christophe , Commeyras Auguste , Pascal Robert
Published: December 2009

The synthesis and characterisation of new arborescent architectures of poly(L‐lysine), called lysine dendrigraft (DGL) polymers, are described. DGL polymers were prepared through a multiple‐generation scheme (up to generation 5) in a weakly acidic aqueous medium by polycondensing Nε‐trifluoroacetyl‐L‐lysine‐N‐carboxyanhydride (Lys(Tfa)‐NCA) onto the previous generation G(n−1) of DGL, which was used as a macroinitiator. The first generation employed spontaneous NCA polycondensation in water without a macroinitiator; this afforded low‐molecular‐weight, linear poly(L‐lysine) G1 with a polymerisation degree of 8 and a polydispersity index of 1.2. The spontaneous precipitation of the growing Nε‐Tfa‐protected polymer (GnP) ensures moderate control of the molecular weight (with unimodal distribution) and easy work‐up. The subsequent alkaline removal of Tfa protecting groups afforded generation Gn of DGL as a free form (with 35–60 % overall yield from NCA precursor, depending on the DGL generation) that was either used directly in the synthesis of the next generation (G(n+1)) or collected for other uses. Unprotected forms of DGL G1–G5 were characterised by size‐exclusion chromatography, capillary electrophoresis and 1H NMR spectroscopy. The latter technique allowed us to assess the branching density of DGL, the degree of which (ca. 25 %) turned out to be intermediate between previously described dendritic graft poly(L‐lysines) and lysine dendrimers. An optimised monomer (NCA) versus macroinitiator (DGL G(n−1)) ratio allowed us to obtain unimodal molecular weight distributions with polydispersity indexes ranging from 1.3 to 1.5. Together with the possibility of reaching high molecular weights (with a polymerisation degree of ca. 1000 for G5) within a few synthetic steps, this synthetic route to DGL provides an easy, cost‐efficient, multigram‐scale access to dendritic polylysines with various potential applications in biology and in other domains.
Chirality in Dynamic Supramolecular Nanotubes Induced by a Chiral Solvent
Authors: Isare Benjamin , Linares Mathieu , Zargarian Loussiné , Fermandjian Serge , Miura Motofumi , Motohashi Shigeyasu , Vanthuyne Nicolas , Lazzaroni Roberto , Bouteiller Laurent
Published: December 2009

Amplification of chirality has been reported in polymeric systems. It has also been shown that related effects can occur in polymer‐like dynamic supramolecular aggregates, if a subtle balance between noncovalent interactions allows the coupling between a chiral information and a cooperative aggregation process. In this context, we report a strong majority‐rules effect in the formation of chiral dynamic nanotubes from chiral bisurea monomers. Furthermore, similar helical nanotubes (with the same circular dichroism signature) can be obtained from racemic monomers in a chiral solvent. Competition experiments reveal the relative strength of the helical bias induced by the chiral monomer or by the chiral solvent. The nanotube handedness is imposed by the monomer chirality, whatever the solvent chirality. However, the chirality of the solvent has a significant effect on the degree of chiral induction.
Physicochemical Characterization of Transport in Nanosized Membrane Structures
Authors: Darvishmanesh Siavash , Degrève Jan , Van der Bruggen Bart
Published: December 2009

The understanding of polymer–solvent interactions is highly important for the development of tailored membrane manufacturing procedures and for the prediction of membrane performance from transport mechanisms. This study examines the permeation performance of organic solvents through state‐of‐the‐art polyimide membranes (STARMEM, Membrane Extraction Technology Ltd.). Solvents are systematically selected to allow investigation of the effects of key physicochemical transport parameters by keeping constant all other parameters thought to be relevant. The effect of the solubility parameter, polarity (dielectric constant), surface tension, and viscosity are studied in detail. Dead‐end permeation experiments are carried out at 20 bar with STARMEM 122 and STARMEM 240 membranes. Results for the selected solvents show higher permeation rates for ketones over alcohols and aromatics as well as for acids. It is suggested that the viscosity and polarity have a greater influence than the other parameters. The effect of solvent molar volume is also investigated. Transport of solvents with high molar volume, independent of their polarity and compatibility with the membrane material, is slower in all cases than for solvents with smaller molar volume. The solubility parameter does not show any significant effect on transport phenomena.
Very Low Energy Electrons Transform the Cyclobutane‐Pyrimidine Dimer into a Highly Reactive Intermediate
Authors: Edtbauer Achim , Denifl Stephan , Vizcaino Violaine , An der Lan Lukas , Russell Katherine , Taubitz Jörg , Wille Uta , Feketeova Linda , O'Hair Richard A. J. , Märk Tilmann D. , Illenberger Eugen , Scheier Paul
Published: December 2009

Electrons with virtually no kinetic energy (close to 0 eV) trigger the decomposition of cytotoxic cyclobutane‐pyrimidine dimer (CPD) into a surprisingly large variety of fragment ions plus their neutral counterparts. The response of CPD to low energy electrons is thus comparable to that of explosives like trinitrotoluene (TNT). The dominant unimolecular reaction is the splitting into two thymine like units, which can be considered as the essential molecular step in the photolyase of CPD. We find that CPD is significantly more sensitive towards low energy electrons than its thymine building blocks. It is proposed that electron attachment at very low energy proceeds via dipole bound states, supported by the large dipole moment of the molecule (6.2 D). These states act as effective doorways to dissociative electron attachment (DEA).
Development of a flow cytometric co‐immunoprecipitation technique for the study of multiple protein—protein interactions and its application to T‐cell receptor analysis
Authors: Bridgeman John S. , Blaylock Morgan , Hawkins Robert E. , Gilham David E.
Published: December 2009

Co‐immunoprecipitation is the classical approach for investigating protein–protein interactions. Analysis is generally conducted using the Western blot approach. We set out to investigate whether flow cytometry was a feasible alternative to Western blotting. Using the TCR‐CD3 complex as a model for intermolecular interactions in the MA5.8 cell line, FLAG‐tagged CD3ζ‐scFv fusion proteins could be captured on anti‐FLAG coupled beads and associated TCRβ molecules could be detected by flow cytometry. This association was abrogated by mutations to the CD3ζ transmembrane domain. Using multicolor flow cytometry, TCRβ, CD3ε, and the scFv region of the CD3ζ fusion molecule could all be detected from a single sample. This multicolor analysis was then applied to demonstrate the importance of correct lysis conditions for extraction of the TCR complex. In summary, this flow cytometric immunoprecipitation technique is a feasible alternative to classical co‐immunoprecipitation analysis technique and offers many potential advantages including rapid analysis with increased target sensitivity, reduced technical demands, amenable to multiple protein analysis from a single sample, and provides a framework that may facilitate the development of high throughput analytical assays investigating protein–protein interactions. © 2009 International Society for Advancement of Cytometry
Characterization of the neuroligin gene family expression and evolution in zebrafish
Authors: Rissone Alberto , Sangiorgio Lorenzo , Monopoli Matteo , Beltrame Monica , Zucchi Ileana , Bussolino Federico , Arese Marco , Cotelli Franco
Published: December 2009

Neuroligins constitute a family of transmembrane proteins localized at the postsynaptic side of both excitatory and inhibitory synapses of the central nervous system. They are involved in synaptic function and maturation and recent studies have linked mutations in specific human Neuroligins to mental retardation and autism. We isolated the human Neuroligin homologs in Danio rerio. Next, we studied their gene structures and we reconstructed the evolution of the Neuroligin genes across vertebrate phyla. Using reverse‐transcriptase polymerase chain reaction, we analyzed the expression and alternative splicing pattern of each gene during zebrafish embryonic development and in different adult organs. By in situ hybridization, we analyzed the temporal and spatial expression pattern during embryonic development and larval stages and we found that zebrafish Neuroligins are expressed throughout the nervous system. Globally, our results indicate that, during evolution, specific subfunctionalization events occurred within paralogous members of this gene family in zebrafish. Developmental Dynamics 239:688–702, 2010. © 2009 Wiley‐Liss, Inc.
Sperm and oocyte communication mechanisms controllingC. elegansfertility
Authors: Han Sung Min , Cottee Pauline A. , Miller Michael A.
Published: December 2009

During sexual reproduction in many species, sperm and oocyte secrete diffusible signaling molecules to help orchestrate the biological symphony of fertilization. In theCaenorhabditis elegansgonad, bidirectional signaling between sperm and oocyte is important for guiding sperm to the fertilization site and inducing oocyte maturation. The molecular mechanisms that regulate sperm guidance and oocyte maturation are being delineated. Unexpectedly, these mechanisms are providing insight into human diseases, such as amyotrophic lateral sclerosis, spinal muscular atrophy, and cancer. Here we review sperm and oocyte communication inC. elegansand discuss relationships to human disorders. Developmental Dynamics 239:1265–1281, 2010. © 2009 Wiley‐Liss, Inc.
A hybrid multirate MAC protocol providing trade‐off between throughput and fairness in future TD‐CDMA networks
Authors: Vlacheas Panagiotis T. , Kolokotroni Eleni A. , Tragos Elias Z. , Theologou Michael E.
Published: December 2009

In this paper, a hybrid, frequency division duplex (FDD), time division–code division multiple access (TD‐CDMA), medium access control (MAC) protocol is proposed. Both multicode (MC) and orthogonal variable spreading factor (OVSF) transmission modes are used in order to utilise the system resources more efficiently. Moreover, a new rate‐scheduling algorithm is developed, aimed at providing a trade‐off between throughput maximisation and fairness, while satisfying QoS requirements. The above scheme is formulated as a constrained optimisation problem, which maximises the sum of normalised rates instead of throughput in order to achieve fairer rate allocations, while maintaining throughput at a high value. A new optimisation constraint is introduced in order to deal with the discrete set of available rates that the hybrid MC‐OVSF scheme supports. Copyright © 2009 John Wiley & Sons, Ltd.
Brief problem‐solving treatment in primary care (pst‐pc) was not more effective than placebo for elderly patients screened positive of psychological problems
Authors: Lam Cindy L. K. , Fong Daniel Y. T. , Chin Weng‐Yee , Lee Peter W. H. , Lam Elegance T. P. , Lo Yvonne Y. C.
Published: December 2009

Objectives

To evaluate whether screening followed by brief problem‐solving treatment by primary care doctors (PST‐PC) could improve health‐related quality of life (HRQOL) and reduce consultation rates in the elderly.

Design

A single‐blind randomized placebo controlled trial (RCT).

Setting

Two government funded primary care clinics in Hong Kong.

Participants

Two hundred and ninety nine Chinese patients aged 60 years or over, with positive screening scores for psychological problems by the Hospital Anxiety and Depression Scale (HADS).

Interventions

One hundred and forty nine subjects were randomized to receive brief PST‐PC from primary care doctors (treatment) and 150 to group video‐viewing (placebo). All subjects were followed up by telephone at 6, 12, 26 and 52 weeks.

Main Outcome Measures

Changes in SF‐36 HRQOL scores, HADS scores and monthly consultation rates were compared within and between groups.

Results

Study completion rates were 69–71%. There was significant improvement in the SF‐36 role‐emotional (RE) and mental component summary (MCS) scores at week 6 in the PST‐PC group but not in the placebo group. Several SF‐36 scores improved significantly in the placebo (video) group at week 6–52. Mixed effects analysis adjusting for baseline values and cofounders did not show any difference in any of the outcomes between the PST‐PC and placebo (video) groups.

Conclusions

Screening followed by brief PST‐PC was associated with a short‐term improvement in HRQOL in Chinese elderly patients screened positive of psychological problems, but the HRQOL benefit was not greater than those found in the placebo group who participated in group‐viewings of health education videos. Copyright © 2009 John Wiley & Sons, Ltd.
Liver Injury in Acute Fatty Liver of Pregnancy: Possible Link to Placental Mitochondrial Dysfunction and Oxidative Stress
Authors: Natarajan Sathish Kumar , Thangaraj Kavitha R. , Eapen C. E. , Ramachandran Anup , Mukhopadhya Ashis , Mathai Mathews , Seshadri Lakshmi , Peedikayil Abraham , Ramakrishna Banumathi , Balasubramanian Kunnissery A.
Published: December 2009

Acute fatty liver of pregnancy (AFLP) is a rare disorder which is fatal if not recognized and treated early. Delivery of the feto-placental unit results in dramatic improvement in maternal liver function, suggesting a role for the placenta. However, the mechanisms by which defects in the fetus or placenta lead to maternal liver damage are not well understood and form the focus of this study. Placenta and serum were obtained at delivery from patients with AFLP, and placental mitochondria and peroxisomes were isolated. Placental mitochondrial function, oxidative stress, and fatty acid composition as well as serum antioxidants, oxidative and nitrosative stress markers, and fatty acid analysis were carried out. Hepatocytes in culture were used to evaluate cell death, mitochondrial function, and lipid accumulation on exposure to fatty acids. Oxidative stress was evident in placental mitochondria and peroxisomes of patients with AFLP, accompanied by compromised mitochondrial function. Increased levels of arachidonic acid were also seen in AFLP placenta when compared to control. Patients with AFLP also had a significant increase in oxidative and nitrosative stress markers in serum, along with decreased antioxidant levels and elevated levels of arachidonic acid. These levels of arachidonic acid were capable of inducing oxidative stress in hepatocyte mitochondria accompanied by induction of apoptosis. Exposure to arachidonic acid also resulted in increased lipid deposition in hepatocytes.

Conclusion:

Oxidative stress in placental mitochondria and peroxisomes is accompanied by accumulation of toxic mediators such as arachidonic acid, which may play a causative role in maternal liver damage seen in AFLP. (Hepatology 2010;51:191–200.)
IκB Kinase ε: A Potential Therapeutic Target for Obesity (and Nonalcoholic Fatty Liver Disease)?
Authors: Nelson James E. , Kowdley Kris V.
Published: December 2009

Abstract

Obesity is associated with chronic low-grade inflammation that negatively impacts insulin sensitivity. Here, we show that high-fat diet can increase NF-κB activation in mice, which leads to a sustained elevation in level of IκB kinase ε (IKKε) in liver, adipocytes, and adipose tissue macrophages. IKKε knockout mice are protected from high-fat diet-induced obesity, chronic inflammation in liver and fat, hepatic steatosis, and whole-body insulin resistance. These mice show increased energy expenditure and thermogenesis via enhanced expression of the uncoupling protein UCP1. They maintain insulin sensitivity in liver and fat, without activation of the proinflammatory JNK pathway. Gene expression analyses indicate that IKKε knockout reduces expression of inflammatory cytokines, and changes expression of certain regulatory proteins and enzymes involved in glucose and lipid metabolism. Thus, IKKε may represent an attractive therapeutic target for obesity, insulin resistance, diabetes, and other complications associated with these disorders.
N -Acetylcysteine on Its Way to A Broader Application in Patients With Acute Liver Failure
Authors: Koch Alexander , Trautwein Christian
Published: December 2009

Abstract

BACKGROUND & AIMS:

N-acetylcysteine (NAC), an antidote for acetaminophen poisoning, might benefit patients with non-acetaminophen-related acute liver failure.

METHODS:

In a prospective, double-blind trial, acute liver failure patients without clinical or historical evidence of acetaminophen overdose were stratified by site and coma grade and assigned randomly to groups that were given NAC or placebo (dextrose) infusion for 72 hours. The primary outcome was overall survival at 3 weeks. Secondary outcomes included transplant-free survival and rate of transplantation.

RESULTS:

A total of 173 patients received NAC (n = 81) or placebo (n = 92). Overall survival at 3 weeks was 70% for patients given NAC and 66% for patients given placebo (1-sided P = .283). Transplant-free survival was significantly better for NAC patients (40%) than for those given placebo (27%; 1-sided P = .043). The benefits of transplant-free survival were confined to the 114 patients with coma grades I-II who received NAC (52% compared with 30% for placebo; 1-sided P = .010); transplant-free survival for the 59 patients with coma grades III-IV was 9% in those given NAC and 22% in those given placebo (1-sided P = .912). The transplantation rate was lower in the NAC group but was not significantly different between groups (32% vs 45%; P = .093). Intravenous NAC generally was well tolerated; only nausea and vomiting occurred significantly more frequently in the NAC group (14% vs 4%; P = .031).

CONCLUSIONS:

Intravenous NAC improves transplant-free survival in patients with early stage non-acetaminophen-related acute liver failure. Patients with advanced coma grades do not benefit from NAC and typically require emergency liver transplantation.
Cigarette Smoking Exacerbates Nonalcoholic Fatty Liver Disease in Obese Rats
Authors: Azzalini Lorenzo , Ferrer Elisabet , Ramalho Leandra N. , Moreno Montserrat , Domínguez Marlene , Colmenero Jordi , Peinado Víctor I. , Barberà Joan A. , Arroyo Vicente , Ginès Pere , Caballería Joan , Bataller Ramón
Published: December 2009

The prevalence of cigarette smoking (CS) is increased among obese subjects, who are susceptible to develop nonalcoholic fatty liver disease (NAFLD). We investigated the hepatic effects of CS in control and obese rats. Control and obese Zucker rats were divided into smokers and nonsmokers (n = 12 per group). Smoker rats were exposed to 2 cigarettes/day, 5 days/week for 4 weeks. The effects of CS were assessed by biochemical analysis, hepatic histological examination, immunohistochemistry, and gene expression analysis. Phosphorylation of AKT and extracellular signal-regulated kinase (ERK) and quantification of carbonylated proteins were assessed by western blotting. As expected, obese rats showed hypercholesterolemia, insulin resistance, and histological features of NAFLD. Smoking did not modify the lipidic or glucidic serum profiles. Smoking increased alanine aminotransferase serum levels and the degree of liver injury in obese rats, whereas it only induced minor changes in control rats. Importantly, CS increased the histological severity of NAFLD in obese rats. We also explored the potential mechanisms involved in the deleterious effects of CS. Smoking increased the degree of oxidative stress and hepatocellular apoptosis in obese rats, but not in controls. Similarly, smoking increased the hepatic expression of tissue inhibitor of metalloproteinase-1 and procollagen-alpha2(I) in obese rats, but not in controls. Finally, smoking regulated ERK and AKT phosphorylation. The deleterious effects of CS were not observed after a short exposure (5 days).

Conclusion:

CS causes oxidative stress and worsens the severity of NAFLD in obese rats. Further studies should assess whether this finding also occurs in patients with obesity and NAFLD. (Hepatology 2010.)
Hepatitis B Virus Activates Deoxynucleotide Synthesis in Nondividing Hepatocytes by Targeting the R2 Gene
Authors: Cohen Dorit , Adamovich Yaarit , Reuven Nina , Shaul Yosef
Published: December 2009

Hepatitis B virus (HBV) causes liver diseases from acute hepatitis to cirrhosis and liver cancer. Currently, more than 350 million people are chronic HBV carriers, with devastating prognosis. HBV is a small enveloped noncytopathic virus, containing a circular partially double-stranded DNA genome, and exhibits strong tropism for human liver cells. Infected individuals (acute and chronic) secrete about 107 to 1011 virions per day to the bloodstream, with each infected cell releasing 50-300 viruses per day. HBV infects nondividing hepatocytes and replicates by reverse-transcribing the pregenomic RNA to DNA in the host cells. The level of deoxyribonucleotide triphosphates (dNTPs) in nondividing cells is too low to support viral replication and enable the high yield of secreted virions. Here, we report production of dNTPs by viral-dependent transcription activation of R2, the key component of ribonucleotide reductase (RNR), and show that this process is critical for the HBV life-cycle. This was found in an established HBV-positive cell line and was reproduced by HBV DNA–transduced cells, in both culture and mice. Furthermore, the viral hepatitis B X protein is essential in activating R2 expression by blocking access of Regulatory factor x1, a repressor of the R2 gene.

Conclusion:

Our findings demonstrate that the hepatitis B X protein is critical in infecting nonproliferating hepatocytes, which contain a low dNTP level. In addition, we provide molecular evidence for a new mechanism of HBV–host cell interaction where RNR-R2, a critical cell-cycle gene, is selectively activated in nonproliferating cells. This mechanism may set the stage for formulating a new category of anti-HBV drugs. (Hepatology 2010)
Synthesis of N‐methylmorpholine N‐(17O‐oxide) and N‐methylmorpholine 15N‐(17O‐oxide)
Authors: Opietnik Martina , Potthast Antje , Kitaoka Takuya , Rosenau Thomas
Published: December 2009

N‐Methylmorpholine N‐(17O‐oxide) and N‐methylmorpholine 15N‐(17O‐oxide) were prepared from N‐methylmorpholine and 15N‐methylmorpholine by oxidation with H2 17O2. The facile one‐pot procedure provided yields of 82 and 76%, respectively. The labeled hydrogen peroxide was obtained by electrolysis of H2 17O followed by autoxidation of 2‐ethylanthraquinol with the molecular oxygen 17O2 generated. The compounds serve for mechanistic studies into gold nanoparticle generation in NMMO solution. Copyright © 2009 John Wiley & Sons, Ltd.
The utilization of rice bran wax to stabilize long chain ω‐3 polyunsaturated fatty acid esters
Authors: Kodali Dharma R.
Published: December 2009

Oils containing long chain ω‐3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are highly susceptible to oxidation, limiting their use in food products and drinks. To stabilize these oils, they are usually fortified with natural and/or synthetic antioxidants. Here we report for the first time the use of a novel natural and edible ingredient, rice bran wax (RBX), that improves the oxidative stability of polyunsaturated ω‐3 oils. When the wax esters are dissolved in polyunsaturated oils at low concentrations (⪈0.5%) and cooled, the wax molecules solidify into a thin crystalline mesh and entrap large volumes of liquid oil. Such encapsulated solids with large volumes of liquid oil are called organogels. Encapsulated menhaden oil with 1.5% RBX containing no added anti‐oxidant, showed oxidative stability comparable to menhaden oil with 500 ppm of tocopherols and 200ppm tert‐butylhydroquinone (TBHQ). Incorporation of RBX to stabilize ω‐3 oils is advantageous as it provides a “natural” label at a modest cost.
Cellular Evaluation of Synthesized Insulin/Transferrin Bioconjugates for Oral Insulin Delivery Using Intelligent Complexation Hydrogels
Authors: Shofner Justin P. , Phillips Margaret A. , Peppas Nicholas A.
Published: December 2009

Insulin transport across the epithelial cell layer in the small intestine was studied using insulin/transferrin conjugates with and without the presence of P(MAA‐g‐EG) microparticles in contact with a co‐culture of Caco‐2/HT29‐MTX cells. The insulin/transferrin conjugate was shown to increase transport relative to pure insulin by a factor of 7, achieving an apparent permeability of 37 × 109 cm · s−1. The presence of P(MAA‐g‐EG) microparticles increased conjugate transport by a factor of 14 times relative to insulin, achieving an apparent permeability of 72.8 × 109 cm · s−1. The presence of the microparticles in solution was found to improve conjugate transport by nearly 100% with little to no change in cell monolayer integrity.

magnified image
Photochemical Reactions of Poly(4‐vinylphenol) Thin Films
Authors: Uppalapati Suji , Chada Sailaja , Engelhard Mark H. , Yan Mingdi
Published: December 2009

The mechanism involved in the photochemical immobilization of poly(4‐vinylphenol) (PVP) thin films was investigated. The films were fabricated by a simple procedure of UV irradiation and solvent extraction. A combination of ellipsometry, IR, and high‐resolution X‐ray photoelectron spectroscopy (XPS) was used to provide detailed and quantitative analysis of the composition of the photochemical reaction products. Upon irradiation at 260 nm, benzyl and phenoxy radicals are generated in the polymer. In the absence of oxygen, PVP films crosslinked via the combination of the benzyl radicals or phenoxy radicals. At lower irradiation doses, the photochemical process was dominated by crosslinking of the polymer backbone via the combination of benzyl radicals. At higher exposure doses, crosslinked quinoid structures were generated, and the concentration increased with the irradiation time. No oxidation or degradation products were observed. In the presence of oxygen, additional reactions of oxidation and degradation occurred. At lower doses, oxidation at the benzyl position produced the ketone structure evidenced by the drastic increase in the O content in the irradiated films. As the irradiation doses increased, further oxidation at the methylene position occurred, and in addition, volatile and degradation products were also generated. This photochemical process was successfully employed to fabricate patterned PVP structures.

magnified image
ATRP of Styrene and Methyl Methacrylate with Less Efficient Catalysts and with Alkyl Pseudohalides as Initiators/Chain Transfer Agents
Authors: Kwak Yungwan , Yamamura Yuichi , Matyjaszewski Krzysztof
Published: December 2009

Ligands, such as Me4cyclam and anionically charged BPAA, providing low values of kda and less efficient for ATRP with alkyl halides, were successfully used for ATRP in the presence of alkyl pseudohalides as initiators/chain transfer agents, resulting in well‐controlled PSt and PMMA. Although the catalysts with these ligands provide a poor control for ATRP with alkyl halides as initiators, the pseudohalides such as dithioesters yield well‐controlled concurrent ATRP/RAFT. The propagating radicals were generated directly from the CTA in the absence of conventional radical initiators, such as AIBN, that are required for a conventional RAFT polymerization. This system is an example of the synergetic cooperation between ATRP and RAFT polymerization procedures that suppresses new chain generation by direct activation of CTA with a copper complex to supply radicals and utilizes fast chain transfer reactions to provide control of the polymerization.

magnified image
Maximal operators on variable Lebesgue spaces with weights related to oscillations of Carleson curves
Authors: Karlovich Alexei Yu.
Published: December 2009

We prove sufficient conditions for the boundedness of the maximal operator on variable Lebesgue spaces with weights φt,γ (τ) = |(τ – t)γ |, where γ is a complex number, over arbitrary Carleson curves. If the curve has different spirality indices at the point t and γ is not real, then φt,γ is an oscillating weight lying beyond the class of radial oscillating weights considered recently by V. Kokilashvili, N. Samko, and S. Samko (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sheaves of C*‐algebras
Authors: Ara Pere , Mathieu Martin
Published: December 2009

We develop the basics of a theory of sheaves of C*‐algebras and, in particular, compare it to the existing theory of C*‐bundles. The details of two fundamental examples, the local multiplier sheaf and the injective envelope sheaf, are discussed (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Toeplitz matrices with variable coefficients, pseudodifferential operators, and Strichartz's method
Authors: Shargorodsky Eugene
Published: December 2009

We present simple proofs of sharp uniform boundedness results for sequences of Toeplitz matrices with variable coefficients. These proofs are based on Strichartz's method which reduces the problem of boundedness of operators “with variable coefficients” to the same problem for operators that have “constant coefficients” but act on Hilbert space valued functions. The paper also contains counterexamples showing the optimality of the boundedness results obtained with the help of Strichartz's method and a brief discussion of similar results for pseudodifferential operators (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erhard Schmidt and his contributions to functional analysis
Authors: Pietsch Albrecht
Published: December 2009

Erhard Schmidt is considered to be one of the leading German mathematicians in the first half of the twentieth century. This article is a tribute to him that was written on the occasion of the 50thanniversary of his death (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical integration and discrepancy, a new approach
Authors: Triebel Hans
Published: December 2009

The paper deals with two closely related topics: (i) Numerical integration of functions belonging to Sobolev‐Besov spaces with dominating mixed smoothness in cubes. (ii) Discrepancy measured in terms of Lebesgue and Sobolev‐Besov spaces (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymer Single Crystal Templated Janus Nanoparticles
Authors: Wang Bingbing , Li Bing , Ferrier Robert C. M. , Li Christopher Y.
Published: December 2009

Top‐selective surface modification has been widely used for the synthesis of Janus nanoparticles (NPs). Herein we demonstrate that polymer single crystals can serve as generic substrates to immobilize NPs and the resultant NPs are Janus in nature. This technique is generic because various NPs as well as polymer single crystal substrates can be used. Single crystals of poly(ethylene oxide), polycaprolactone, and polyethylene‐block‐poly(ethylene oxide) have been successfully used to immobilize gold, magnetic, and semiconducting NPs. Subsequent dissolution of the single crystals led to various types of Janus NPs and NP clusters with different polymer brushes.

magnified image
Synthesis and characterization of phenolic‐type beads by dispersion polymerization of 2‐phenoxyethanol with formaldehyde using gum acacia powder as stabilizer
Authors: Liu Li , Ji Chunnuan , Song Shuhui , Sun Changmei , Qu Rongjun , Wang Chunhua , Chen Hou
Published: December 2009

In this study, we report the preparation of phenolic beads (PB) via a novel dispersion polymerization of 2‐phenoxyethanol (PE) and formaldehyde, in which gum acacia powder (GAP), formic acid, and sulfuric acid are employed as the steric stabilizer, the reaction medium and the catalyst, respectively. The effects of a variety of reaction parameters, including the stabilizer concentration, the agitation rate, the polymerization temperature, the molar ratio of formaldehyde to 2‐phenoxyethanol (F/P) and the amount of sulfuric acid, on the particle size and size distribution (PDI) as well as particle morphology have been investigated. Particularly, phenolic beads of a size 565 µm as well as a narrow particle size distribution (PDI = 1.153) have been prepared under the following conditions: the stabilizer concentration 2.5%, the agitation rate 700 rpm, the polymerization temperature 60°C, the molar F/P ratio 3:1, and the amount of catalyst 8 ml. In addition, a mechanism for the particle formation in dispersion polymerization of PE and formaldehyde has also been proposed. Copyright © 2009 John Wiley & Sons, Ltd.
Hochkontagiöse Erkrankungen. Sind wir vorbereitet?
Authors: Stich August , Gottschalk René
Published: December 2009

Hochkontagiöse, gemeingefährliche, lebensbedrohliche Erkrankungen kommen in Deutschland bislang extrem selten vor, bergen aber ein hohes Gefahrenpotential für Patienten, Gesundheitspersonal und die allgemeine Bevölkerung. Sie können als importierte Infektionen, bei Laborunfällen oder im Rahmen bioterroristischer Anschläge vorkommen. Besondere Bedeutung haben die Mensch zu Mensch übertragbaren viralen hämorrhagischen Fieber (vor allem Ebola, Marburg, Lassa, Krim‐Kongo hämorrhagisches Fieber), Pockenerkrankungen und die Lungenpest. Anamnese und klinisches Bild erlauben Fachleuten, einen “begründeten Verdacht” auszusprechen, was eine Reihe spezifischer Maßnahmen nach sich ziehen muss. Diese sollten in Alarmplänen vorbereitet sein, deren Umsetzung ein enges Zusammenspiel zwischen Klinikern, Öffentlichem Gesundheitsdienst und Experten voraussetzt. Deutschland ist durch das Netzwerk der StAKoB im internationalen Vergleich sehr gut aufgestellt.
Impfungen in der Tropen‐ und Reisemedizin. Hintergrundinformationen für die Beratung
Authors: Müller Andreas
Published: December 2009

Impfungen vor Reisen sind eine effektive Maßnahme zum Schutz vor potentiell gefährlichen Erkrankungen. Eine Impfempfehlung ist das Resultat einer individuellen Beratung über das Krankheitsbild, die Epidemiologie, erzielte Schutzwirkung, Behandlungsmöglichkeiten und alternative oder additive Schutzmöglichkeiten. Reisemedizinische Impfungen müssen nicht kosteneffektiv sein sondern sie dienen der Minimierung individueller Gesundheitsrisiken unter Berücksichtigung des angestrebten Sicherheitsniveaus.
A continuous spectrophotometric assay for determination of the aureusidin synthase activity of tyrosinase
Authors: Jiménez‐Atiénzar M. , Pérez‐Gilabert M. , Cabanes J. , Escribano J. , Gandía‐Herrero F. , García‐Carmona F.
Published: December 2009

Introduction – Aurones (aureusidin glycosides) are plant flavonoids that provide yellow colour to the flowers of some ornamental plants. In this study we analyse the capacity of tyrosinase to catalyse the synthesis of aureusidin by tyrosinase from the chalcone THC (2′,4′,6′,4–tetrahydroxychalcone).

Objective – To develop a simple continuous spectrophotometric assay for the analysis of the spectrophotometric and kinetic characteristics of THC oxidation by tyrosinase.

Methodology – THC oxidation was routinely assayed by measuring the increase in absorbance at 415 nm vs. reaction time.

Results – According to the mechanism proposed for tyrosinase, the enzymatic reaction involves the o‐hydroxylation of the monophenol THC to the o‐diphenol (PHC, 2′,4′,6′,3,4 – pentahydroxychalcone), which is then oxidised to the corresponding o‐quinone in a second enzymatic step. This product is highly unstable and thus undergoes a series of fast chemical reactions to produce aureusidin. In these experimental conditions, the optimum pH for THC oxidation is 4.5. The progress curves obtained for THC oxidation showed the appearance of a lag period. The following kinetic parameters were also determined: Km = 0.12 mM, Vm = 13 μM/min, Vm/Km = 0.11/min.

Conclusion – This method has made it possible to analyse the spectrophotometric and kinetic characteristics of THC by tyrosinase. This procedure has the advantages of a short analysis time, straightforward measurement techniques and reproducibility. In addition, it also allows the study of tyrosinase inhibitors, such as tropolone. Copyright © 2009 John Wiley & Sons, Ltd.
Hospital pharmacists' knowledge and opinions regarding adverse drug reaction reporting in Northern China
Authors: Su Changhai , Ji Hui , Su Yixin
Published: December 2009

Purpose

This study was designed to investigate the knowledge and opinions of hospital pharmacists about the spontaneous reporting of adverse drug reactions (ADRs) in Inner Mongolia, a northern region of China.

Methods

A face‐to‐face questionnaire survey of hospital pharmacists was conducted in five tertiary general hospitals in Inner Mongolia between July and December 2007. The structured questionnaire consisted of questions about the demographic details of the pharmacists, their knowledge of pharmacovigilance and their opinions on pharmacists' involvement in ADR reporting.

Results

Of the 288 pharmacists visited, 246 responded giving a total response rate of 85.4%. An amount of 70% of the pharmacists could define ADR correctly and 78.0% knew how to report ADRs. However, only one‐third were clear as to what should be reported. The majority of pharmacists (92.7%) considered ADR reporting to be a professional obligation. However, only 36 (14.6%) claimed to have reported an ADR in their career, 25 of these 36 pharmacists (69.4%) were clinical pharmacists. Younger pharmacists and those who had received ADR training were more likely to report an ADR. The three major reasons for not reporting were: uncertain association (81.9%), insufficient clinical knowledge (68.6%) and lack of time (45.7%). The most frequently mentioned suggestion for improvement included more education on ADR reporting (66.7%), participation in ward rounds (43.9%) and encouragement from the pharmacy department (32.9%).

Conclusion

Our investigation showed hospital pharmacists in a northern region of China had a reasonable knowledge of and positive attitudes towards pharmacovigilance. However, the majority of pharmacists had never reported an ADR in their career. Pharmacists' ADR education and increasing involvement in patient care would be important in improving ADR reporting in hospitals. Copyright © 2009 John Wiley & Sons, Ltd.