bluuebunny/crossref_metadata_2025 huggingface dataset:
Androgens Play a Pivotal Role in Maintaining Penile Tissue Architecture and Erection: A Review
Authors: Traish Abdulmaged M.
Published: July 2009

ABSTRACT: Androgens are essential for development, growth, and maintenance of penile structure, and regulate erectile physiology by multiple mechanisms. Here we provide a concise overview of the basic research findings pertaining to androgen modulation of erectile tissue architecture and physiology. A significant body of evidence exists pointing to a critical role of androgens in erectile physiology. Studies in animal models have provided fundamental knowledge on the role of androgens in modulating tissue architecture and cellular, molecular, and physiological mechanisms. Based on data from our laboratory and those reported by others, we believe that androgens play a pivotal role in maintaining the structure and function of the peripheral penile nerve network, the structural integrity of the corpora cavernosa, the tunica albuginea, and the endothelium of the cavernous spaces. Further, androgens play an important role in regulating the differentiation of precursor cells into trabecular smooth muscle. In this review, we will focus our discussion on findings pertaining to the role of androgens in regulating penile tissue architectural elements in modulating penile function. This knowledge has a profound impact on the potential use of androgens in the clinical setting to treat patients with erectile dysfunction.
Mechanical testing of single yeast cells in liquid environment: Effect of the extracellular osmotic conditions on the failure behavior
Authors: Arfsten Judith , Kampen Ingo , Kwade Arno
Published: July 2009

In industrial biotechnology microbial cells are utilized to produce diverse products (e. g., enzymes, food and animal feed additives, pharmaceutical agents). Whilst relationships on genetic and molecular levels are reasonably understood there are still numerous unsolved questions in matters of the mechanical properties of those cells. Recently, a compression test in liquid environment using a nanoindentation device was established to address the cell mechanical behavior of Saccharomyces cerevisiae (baker's yeast) cells. At higher deformations compressive stressing yielded failure of the cell wall. In the present work, the influence of the extracellular osmotic conditions on the failure characteristics (bursting force, bursting energy, and relative deformation at bursting) was studied. Moreover, a simple mechanical model was applied to characterize the mechanical properties of the cell wall.
Effect of seeding sludge type and hydrodynamic shear force on the aerobic sludge granulation in sequencing batch airlift reactors
Authors: Koh K. Y. , Kueh K. H. , Loh K. T. , Leong H. J. , Chua A. S. M. , Hashim M. A.
Published: July 2009

Two sequencing batch airlift reactors (SBARs) were operated simultaneously for two separate runs. In the first run, two different types of seeding sludge were cultivated in two separate reactors under the same superficial air velocity (SAV). In the second run, the same seeding sludge was cultivated in both reactors but under different SAV, i.e. 1.2 and 3.6 cm s−1. Both runs were carried out for a period of about 20 days, during which the chemical oxygen demand (COD) removal efficiency and morphology of sludge were examined. Batch tests using sodium acetate as the main carbon source were conducted to investigate the COD removal efficiency, and the morphologies of sludge were examined under light microscopy. Results showed that the COD removal efficiency improved with cultivation time. Morphological study showed that all cultivated sludge lost their filamentous species after a few days of cultivation, leaving behind communities of loosely packed pellet‐like groups. Although the SAV recommended by other researchers was applied to the SBAR, granulation did not take place at the end of both experimental runs. It was suspected that the failure for aerobic sludge to granulate under the selected operating strategies and reactor configuration was partly due to the intrinsic traits of the sludge microbial community. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Optimal operation of tubular reactors for naphtha cracking by numerical simulation
Authors: Gao G.‐Y. , Wang M. , Ramshaw C. , Li X.‐G. , Yeung H.
Published: July 2009

Process gas temperature profile and steam‐to‐hydrocarbon ratio in the feed have important impact on product yields and coking rate in tubular reactors for naphtha cracking. This study is to evaluate these effects quantitatively based on numerical simulation. Steady‐state operation of the tubular reactor in an industrial thermal cracking furnace was first simulated in HYSYS with a molecular reaction scheme. Various case studies then investigate the influence of process gas temperature profile and inlet steam‐to‐hydrocarbon ratio so that the ethylene/propylene product yields and coking rate can be evaluated. Finally, steady‐state optimization was applied to the operation of this industrial furnace. The optimal process temperature profile and the optimal inlet steam‐to‐naphtha ratio were found to maximize the operation profit. This study will provide significant guidance to process engineers in the ethylene industry. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
The use of self‐interaction chromatography in stable formulation and crystallization of proteins
Authors: Deshpande Kedar S. , Ahamed Tangir , ter Horst Joop H. , Jansens Peter J. , van der Wielen Luuk A. M. , Ottens Marcel
Published: July 2009

This paper reviews the basic principles of the recently developed self‐interaction chromatography (SIC) technique with regard to protein solution stability and protein crystallization. It gives experimental protocols for both normal‐scale and micro‐scale SIC experiments and reviews recent developments and current applications of this novel technique in the biopharmaceutical area. This paper aims to be a benchmark in the further proliferation of this highly effective and fast technology for the rational design of stable aqueous formulations of therapeutic proteins and the determination of solution conditions favoring protein crystallization.
Modification of plant hormone levels and signaling as a tool in plant biotechnology
Authors: Csukasi Fabiana , Merchante Catharina , Valpuesta Victoriano
Published: July 2009

Plant hormones are signal molecules, present in trace quantities, that act as major regulators of plant growth and development. They are involved in a wide range of processes such as elongation, flowering, root formation and vascular differentiation. For many years, agriculturists have applied hormones to their crops to either increase the yield, or improve the quality of the commercial product. Nowadays, the knowledge of hormone biosynthesis, degradation and signaling pathways has allowed the utilization of biotechnological tools to further improve the main agricultural crops. Natural or artificial mutants, with impaired functioning of the corresponding genes, have been adopted because of their superior phenotype in specific agricultural traits. In addition, transgenic plants have been generated to regulate internal hormone levels, or their signaling pathways, resulting in some crops that have revolutionized agriculture.
Purification of homogeneous forms of fungal peroxygenase
Authors: Ullrich René , Liers Christiane , Schimpke Sylvia , Hofrichter Martin
Published: July 2009

Extracellular peroxygenase from the agaric fungus Agrocybe aegerita is a versatile biocatalyst that oxygenates various substrates by means of hydrogen peroxide. The enzyme is routinely produced in suspensions of soybean meal and has until now been purified by several steps of fast protein liquid chromatography (FPLC) using different ion exchangers. The final protein fraction had a molecular mass of 46 kDa but still consisted of several incompletely separated proteins with slightly differing isoelectric points (pI 5.2, 5.6, 6.1), probably representing differently glycosylated isoforms. This made it difficult to further purify the individual protein forms. Since homogeneous protein fractions are a pre‐requisite for X‐ray crystallography and specific structure‐function studies, an appropriate FPLC procedure was developed starting with pre‐purification of crude peroxygenase on SP Sepharose followed by chromatofocusing on a Mono P column and elution with a pH gradient. Three sufficiently separated main protein peaks were eluted from the Mono P column and confirmed to be distinct forms of aromatic peroxygenase with different pIs. All A. aegerita peroxygenase forms oxygenated toluene and naphthalene and no catalytic differences were observed between them. We tested also two devices for preparative isoelectric focusing (Rotofor, IsoPrime systems) for peroxygenase separation but resolution and protein recovery were not sufficient.
Production of L‐DOPA and dopamine in recombinant bacteria bearing the Vitreoscilla hemoglobin gene
Authors: Kurt Asli Giray , Aytan Emel , Ozer Ufuk , Ates Burhan , Geckil Hikmet
Published: July 2009

Given the well‐established beneficial effects of Vitreoscilla hemoglobin (VHb) on heterologous organisms, the potential of this protein for the production of L‐DOPA and dopamine in two bacteria, Citrobacter freundii and Erwinia herbicola, was investigated. The constructed recombinants bearing the VHb gene (vgb+) had substantially higher levels of cytoplasmic L‐DOPA (112 mg/L for C. freundii and 97 mg/L for E. herbicola) than their respective hosts (30.4 and 33.8 mg/L) and the vgb– control strains (35.6 and 35.8 mg/L). Further, the vgb+ recombinants of C. freundii and E. herbicola had 20‐fold and about two orders of magnitude higher dopamine levels than their hosts, repectively. The activity of tyrosine phenol‐lyase, the enzyme converting L‐tyrosine to L‐DOPA, was well‐correlated to cytoplasmic L‐DOPA levels. As cultures aged, higher tyrosine phenol‐lyase activity of the vgb+ strains was more apparent.
Insulin transport across porous charged membranes: Effect of the electrostatic interaction
Authors: Zhang Shaoling , Matsumoto Hidetoshi , Saito Keiichiro , Minagawa Mie , Tanioka Akihiko
Published: July 2009

Insulin transport phenomena across a series of porous charged membranes were studied at two pH conditions (pH 3.3 and pH 7.4) in this article. The membranes were prepared by pore‐surface modification of porous poly(acrylonitrile) (PAN) membranes by grafting with weak acidic and basic functional groups. The insulin partition coefficient K between the membrane and solution was estimated from the equilibrium adsorption amount in the batch adsorption experiment. The insulin effective diffusion coefficient D inside the membrane was determined as a fitting parameter by matching the diffusion model with the experimental data of the diffusion measurement. Both K and D correlated well with the charge properties of the insulin and membrane: when the insulin and membrane carried opposite net charge, the partition coefficient showed relatively larger values, while the effective diffusion coefficient was reduced. The insulin permeability coefficient P obtained from the experimental results agreed with that estimated from the partition coefficient and effective diffusion coefficient. These results suggested that the combined effects of the solubility and diffusivity on the permeability coefficient complicated the relationship between the permeability and the charge properties of the insulin and membrane. Additionally, our calculation supported that insulin permeability was reduced by the boundary layer between the membrane and solution. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Influence of wall thickness on fluid–structure interaction computations of cerebral aneurysms
Authors: Torii Ryo , Oshima Marie , Kobayashi Toshio , Takagi Kiyoshi , Tezduyar Tayfun E.
Published: July 2009

Fluid–structure interaction (FSI) analyses of cerebral aneurysm using patient‐specific geometry with uniform and pathological aneurysmal wall thickness models are carried out. The objective is to assess the influence of the wall thickness on the FSI and hemodynamics in aneurysms. Two aneurysm models that were reconstructured based on CT images are used. The arterial wall thickness is set to 0.3 mm for the non‐aneurysmal artery and to 0.05 mm for the aneurysmal wall based on experimental findings. Another set of aneurysm models with a uniform wall thickness of 0.3 mm for the entire model is used for comparison. The FSI simulations are carried out using the deforming‐spatial‐domain/stabilized space–time method with physiological inflow and pressure profiles. Computations with different aneurysmal wall thicknesses depict considerable differences in displacement, flow velocity and wall shear stress (WSS). The wall displacement for the pathological wall model is 61% larger than that of the uniform wall model. Consequently, the flow velocities in the aneurysm with the pathological wall model are lower, and that results in a 51% reduction in WSS on the aneurismal wall. Because low WSS on the aneurymal wall is linked to growth and rupture risk of aneurysm, the results suggest that using uniform wall thickness for the aneurysmal wall could underestimate risk in aneurysms. Copyright © 2009 John Wiley & Sons, Ltd.
Blood lipid levels in relation to glucose status in seven populations of Asian origin without a prior history of diabetes: the DECODA study
Authors: Zhang L. , Qiao Q. , Tuomilehto J. , Hammar N. , Janus E. D. , Söderberg S. , Mohan V. , Ramachandran A. , Dong Y. H. , Lam T. H. , Pang Z. C.
Published: July 2009

Background

Dyslipidaemia commonly coexists with diabetes. We investigated the association of lipid profiles with glucose levels in populations of Asian origin without a prior history of diabetes.

Methods

Cross‐sectional data of 10 374 men and 12 552 women aged 30–74 years from 14 cohorts, representing seven populations of Asian origin were jointly analysed. Multivariable adjusted linear regression analyses with standardized regression coefficients (β) were performed to estimate relationships between lipids and plasma glucose.

Results

Within each glucose category, fasting plasma glucose (FPG) levels were correlated with increasing levels of triglycerides (TGs), total cholesterol (TC), TC to high‐density lipoprotein (HDL) ratio and non‐HDL cholesterol (non‐HDL‐C) (p < 0.05 in most of the ethnic groups) and inversely associated with HDL‐C (p < 0.05 in some, but not all, of the populations). The association of lipids with 2‐h plasma glucose (2hPG) followed a similar pattern as that for the FPG, except that an inverse relationship between HDL‐C and glucose was more commonly observed for 2hPG than for FPG among different ethnic groups.

Conclusions

Hyperglycaemia is associated with adverse lipid profiles in Asians without a prior history of diabetes. The 2hPG appears to be more closely associated with lipid profiles than does FPG. When assessing the risk of cardiovascular disease, the association of the dyslipidaemia with intermediate hyperglycaemia needs to be considered. Copyright © 2009 John Wiley & Sons, Ltd.
Disposable bioreactors for plant liquid cultures at Litre‐scale
Authors: Eibl Regine , Werner Sören , Eibl Dieter
Published: July 2009

Driven by the demands of the market and the manufacturing industry, disposable bioreactors have gained in importance in cell culture‐based processes during the last 10 years. Today they are widely accepted in R&D and also in manufacturing where process simplicity, safety and flexibility have top priority. Although disposable bioreactors are mainly used for cell expansions, glycoprotein secretions and virus generations realised with mammalian and insect cell lines, there are several reports delineating their suitability for the cultivation of plant cell and tissue cultures. This review describes the current disposable bioreactor types suitable for growing plant cell suspensions and organ cultures (hairy roots, meristematic clusters, somatic embryos) at Litre‐scale. Based on a definition of the term “disposable bioreactor”, a categorisation of the prevalent types for plant liquid cultures is presented. We describe the bioreactor regimes, working principles and bioengineering parameters of mechanically and pneumatically agitated bag bioreactors, which have advantages of process scalability and efficiency. Furthermore, results from the literature and data from our own research (obtained during production of undifferentiated bioactive cells, expressions of secondary metabolites and glycoproteins, and micropropagations of plant tissues) are discussed.
In vitro cartilage formation using TGF‐β‐immobilized magnetic beads and mesenchymal stem cell‐magnetic bead complexes under magnetic field conditions
Authors: Motoyama Mitsuru , Deie Masataka , Kanaya Atsushi , Nishimori Makoto , Miyamoto Ayato , Yanada Shinobu , Adachi Nobuo , Ochi Mitsuo
Published: July 2009

We evaluated the efficacy of transforming growth factor (TGF)‐β‐immobilized magnetic beads for chondrogenesis in vitro using a mesenchymal stem cell (MSC) delivery system and an external magnetic force (EMF). MSCs isolated from the bone marrow of Sprague Dawley rats were mixed with carboxyl group‐combined magnetic beads (Ferri Sphere 100C®) coated with anti‐rat CD44 mouse monoclonal antibodies. TGF‐β3 (10 and 1 ng/mL) was attached magnetically to such other Ferri Sphere 100C® beads via an amide bond formed between a primary amino group on the TGF‐β3 and the carboxyl groups on the surface of the beads. MSC‐magnetic bead complexes were centrifuged to form a pellet and cultured in chondrogenic differentiation medium (CDM) supplemented with either 10 or 1 ng/mL TGF‐β‐immobilized magnetic beads (10 or 1 ng/mL TGF‐β‐immobilized magnetic bead groups) or in CDM supplemented with 1 or 10 ng/mL TGF‐β (1 or 10 ng/mL TGF‐β group). TGF‐β‐immobilized magnetic beads were gathered effectively under an EMF. Chondrogenesis was achieved from the MSC‐magnetic bead complexes in the presence of 1 ng/mL TGF‐β‐immobilized magnetic beads. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Preparation and characterization of polymethacrylate monolithic capillary columns with dual hydrophilic interaction reversed‐phase retention mechanism for polar compounds
Authors: Urban Jiří , Škeříková Veronika , Jandera Pavel , Kubíčková Romana , Pospíšilová Marcela
Published: July 2009

Monolithic columns for capillary hydrophilic interaction liquid chromatography (HILIC) were prepared in fused‐silica capillaries by radical co‐polymerization of [2‐(methacryloyloxy)ethyl]dimethyl‐(3‐sulfopropyl)ammonium hydroxide and ethylene dimethacrylate in various binary and ternary porogen solvent mixtures with azobisisobutyronitrile as the initiator of the polymerization reaction. Columns showed mixed separation modes: reversed‐phase (RP) in water‐rich mobile phases and HILIC at high concentrations of acetonitrile (>60–80%) in aqueous–organic mobile phases. A continuous change in retention was observed at increasing concentration of water in acetonitrile, giving rise to characteristic U‐turn plots of retention factors versus the concentration of water in the mobile phase, with minima corresponding to the transition between the mechanisms controlling the retention. The selectivity of organic polymer monolithic columns for HILIC separations can be varied by adjusting the concentration of sulfobetaine monomer and the composition of the porogen solvent in the polymerization mixture. Under HILIC conditions, the monolithic capillary sulfobetaine columns show separation selectivities for polar phenolic acids similar to those of a commercial silica‐based sulfobetaine ZIC‐HILIC column, which, however, has limited selectivity in the RP mode due to lower retention.
High‐performance separation of small inorganic anions on a methacrylate‐based polymer monolith grafted with [2(methacryloyloxy)ethyl] trimethylammonium chloride
Authors: Connolly Damian , Paull Brett
Published: July 2009

A glycidyl methacrylate‐co‐ethylene dimethacrylate monolith in capillary format (100 μm/id) has been grafted with chains of poly([2(methacryloyloxy)ethyl] trimethylammonium chloride (poly‐META) and applied to the ion‐chromatographic separation of selected inorganic anions. Grafting chains of META onto the generic monolithic scaffold resulted in a monolith with ‘electrolyte responsive flow permeability’, which manifested as increased permeability in the presence of electrolyte solutions. Using an eluent of 2 mM sodium benzoate and on‐column contactless conductivity detection, a test mixture of six common anions was isocratically separated and detected within 12 min, with the first four anions baseline resolved within a retention time window of 3.2 min. Retention time precision was ⪇1.2% for all anions tested. Separation efficiencies of 15 000 N/m were achieved for fluoride at 1 μL/min, with column efficiencies up to 29 500 N/m obtained at a lower flow rate of 100 nL/min. Furthermore, repeatability of the column modification procedure using photografting methods was acceptable, with retention times between replicate columns matching within 9%.
The Effect of Side Chain Length and Hydrogen Bonding on the Viscoelastic Property of Isobutene/Maleimide Copolymers
Authors: Omayu Akitoshi , Yoshioka Shin'ya , Matsumoto Akikazu
Published: July 2009

The viscoelastic properties of the alternating copolymers of N‐substituted maleimides with n‐alkyl and ω‐carboxy‐n‐alkyl groups as the N‐substituent with isobutene were investigated by dynamic mechanical analysis. The transition temperatures in the α‐relaxation region depended on the alkyl chain length and the presence or absence of a terminal carboxy group in the side chain. β‐Relaxation due to side chain dynamics was also observed in a lower temperature region without merging the α‐ and β‐relaxation processes for all the copolymers. The molecular motions of the semiflexible main chain and the flexible side alkyl groups were investigated as well as the intermolecular interaction by hydrogen bonding of the carboxyl groups.

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Choosing hamsters but not rats as a model for studying plasma cholesterol‐lowering activity of functional foods
Authors: Zhang Zesheng , Wang Hao , Jiao Rui , Peng Cheng , Wong Yin Mei , Yeung Venus Sai Ying , Huang Yu , Chen Zhen‐Yu
Published: July 2009

Rats and hamsters are commonly used rodents to test the efficacy of cholesterol‐lowering functional foods. In general, a diet containing 1% cholesterol for rats whereas a diet containing 0.1% cholesterol for hamsters is used to induce the hypercholesterolemia. The present study was carried out to compare hamsters with rats as a hypercholesterolemia model. Golden Syrian hamsters and Sprague Dawley rats were randomly divided into four groups and fed one of the four diets containing 0–0.9% cholesterol. Results demonstrated that serum total cholesterol (TC) in hamsters was raised 73–81% higher than that in rats fed the same cholesterol diets. Unlike rats in which HDL‐C accounted very little for serum TC, the lipoprotein profile in hamsters was closer to that in humans. We investigated interaction of higher cholesterol diets with 3‐hydroxy‐3‐methylglutary‐CoA (HMG‐CoA) reductase, low‐density lipoprotein receptor (LDL‐R) and cholesterol‐7α‐hydroxylase (CYP7A1), sterol regulatory element binding protein‐2 (SREBP‐2), and liver X receptor (LXR‐α). Results showed hamsters and rats metabolized cholesterol differently. In view that hamsters synthesize and excrete cholesterol and bile acids in a manner similar to that in humans, it is concluded that hamsters but not rats shall be chosen as a model to study efficacy of cholesterol‐lowering functional foods.
Continuous Atom Transfer Radical Polymerization with Low Catalyst Concentration in a Tubular Reactor
Authors: Chan Nicky , Boutti Salima , Cunningham Michael F. , Hutchinson Robin A.
Published: July 2009

Continuous ARGET ATRP of butyl methacrylate was carried out in an 850 mL tubular reactor using parts per million levels of copper catalyst and stoichiometric amounts of ligand to copper under industrially relevant conditions without monomer and solvent purification. A copper(II) bromide/tris(2‐pyridylmethyl)amine complex was used as catalyst, and tin(II) 2‐ethylhexanoate was chosen as the reducing agent. It was found that stainless steel fittings and/or storage tanks had an adverse effect on polymerization rate, underlining the importance of the choice of chemically inert tubing. The problem of lower rate was solved by increasing the amount of reducing agent in the system fourfold, under which conditions the molecular weight development and polymerization rate in the tubular system compared well to that in a batch reactor. Thus, ARGET ATRP can be made significantly faster and more robust through the judicious use of an inexpensive and non‐hazardous reducing agent. The tubular reactor produces polymer with a controlled molecular weight distribution continuously and reliably, demonstrating its potential for industrial adoption.

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GPU‐accelerated boundary element method for Helmholtz' equation in three dimensions
Authors: Takahashi Toru , Hamada Tsuyoshi
Published: July 2009

Recently, the application of graphics processing units (GPUs) to scientific computations is attracting a great deal of attention, because GPUs are getting faster and more programmable. In particular, NVIDIA's GPUs called compute unified device architecture enable highly mutlithreaded parallel computing for non‐graphic applications. This paper proposes a novel way to accelerate the boundary element method (BEM) for three‐dimensional Helmholtz' equation using CUDA. Adopting the techniques for the data caching and the double–single precision floating‐point arithmetic, we implemented a GPU‐accelerated BEM program for GeForce 8‐series GPUs. The program performed 6–23 times faster than a normal BEM program, which was optimized for an Intel's quad‐core CPU, for a series of boundary value problems with 8000–128000 unknowns, and it sustained a performance of 167 Gflop/s for the largest problem (1 058 000 unknowns). The accuracy of our BEM program was almost the same as that of the regular BEM program using the double precision floating‐point arithmetic. In addition, our BEM was applicable to solve realistic problems. In conclusion, the present GPU‐accelerated BEM works rapidly and precisely for solving large‐scale boundary value problems for Helmholtz' equation. Copyright © 2009 John Wiley & Sons, Ltd.
Selective and non‐selective non‐steroidal anti‐inflammatory drugs and the risk of acute kidney injury
Authors: Lafrance Jean‐Philippe , Miller Donald R.
Published: July 2009

Purpose

Use of non‐steroidal anti‐inflammatory drugs (NSAID) is associated with risk of acute kidney injury (AKI). Risk of AKI may vary with selectivity of the NSAID, but this has not been studied in a large cohort where AKI was assessed directly from laboratory data. The objective was to compare AKI risk between selective and non‐selective NSAIDs using a laboratory‐based definition of AKI.

Methods

We conducted a retrospective nested case‐control study in the U.S. Department of Veterans Affairs health care system. From a cohort of 1 459 271 new NSAID users, we identified 22 824 cases of AKI (97% male; mean age: 63 years), and 336 734 matched controls between 2000 and 2006. AKI was defined as a creatinine increase of greater than 50%.

Results

We found higher risk of AKI in new users of any single NSAID (adjusted odds ratio = 1.82; 95%CI: 1.68, 1.98) compared to non‐users without recent use. The risk of AKI varied among different NSAIDs with risk generally increasing with decrease in selectivity: rofecoxib (0.95; 0.64, 1.42), celecoxib (0.96; 0.63, 1.47), meloxicam (1.13; 0.63, 2.05), etodolac (1.31; 1.08, 1.59), diclofenac (1.11; 0.84, 1.48), piroxicam (1.53; 1.05, 2.23), salsalate (1.51; 1.22, 1.87), sulindac (1.61; 1.12, 2.30), ibuprofen (2.25, 2.04, 2.49), naproxen (1.72; 1.52, 1.95), high dose aspirin (3.64; 2.46, 5.37), indomethacin (1.94; 1.56, 2.42), keterolac (2.07; 1.78, 2.41). Those using multiple NSAIDs appeared to have higher risk (2.90; 2.62, 3.22).

Conclusions

This study provides evidence that risk of AKI may be lower with more selective agents than with naproxen or other non‐selective NSAIDs. Copyright © 2009 John Wiley & Sons, Ltd.
Modification of poly(ethylene terephthalate) surface with attached dextran macromolecules
Authors: Stetsyshyn Yurij , Donchak Volodymyr , Harhay Khrystyna , Voronov Stanislav , Raczkowska Joanna , Budkowski Andrzej
Published: July 2009

BACKGROUND: Peroxidation of a poly(ethylene terephthalate) (PET) surface clears the path to the formation of biospecific polymeric layers on it. The goal of this work was the modification of a PET surface with oligoperoxides with further grafting of dextran macromolecules to this peroxidated surface.

RESULTS: Novel oligoperoxides with a good affinity to PET were synthesized. They are capable of attaching to the PET surface, due to the decomposition of peroxide groups via the formation of free radicals. The alterations in surface energy and its components as a result of surface modification as well as changes in topography of the PET surface were determined. The degree of modification of the PET surface can reach 68% and depends on the following: the method of oligoperoxide and dextran deposition; the concentration of both oligoperoxide and dextran in the initial solution; and the temperature at which the modification is carried out.

CONCLUSION: A new method of PET surface activation has been developed. The attachment of dextran macromolecules to modified PET surfaces is confirmed. Copyright © 2009 Society of Chemical Industry
Cobalt(II) and nickel(II) complexes bearing mono(imino)pyridyl and bis(imino)pyridyl ligands: preparation, structure and ethylene polymerization/oligomerization behaviors
Authors: Su Biyun , Zhao Jianshe , Zhang Qunzheng , Qin Wenlong
Published: July 2009

BACKGROUND: Ethylene oligomerization is the major industrial process to produce linear α‐olefins. Recently much work has been devoted to late transition metal catalysts used in this process, especially those with 2,6‐bis(imino)pyridyl dihalide ligands. Considering that most work has focused on simple modification to the substituents in imino‐aryl rings based on the symmetric bis(imino)pyridyl framework, here we expand this work to the asymmetric mono(imino)pyridyl ligands.

RESULTS: The preparation, structure and ethylene polymerization/oligomerization behavior of series of mono(imino) pyridyl–MCl2 and bis(imino)pyridyl–MXn complexes are presented. The systematic studies were focused on the relationship between the catalytic behavior of these complexes for ethylene polymerization/oligomerization and reaction conditions, ligand structures, metal centers and counter‐anions. The influence of the coordination environment on catalyst behavior is also discussed.

CONCLUSION: For mono(imino)pyridyl–Co(II) and Ni(II) catalysts bearing the Cl− counter‐anion, good activities ranging from 0.513 × 105 to 1.58 × 105 g polyethylene (mol metal)−1 h−1 atm−1 are afforded, and the most active catalysts are those with methyl in both ortho‐ and para‐positions of the imine N‐aryl ring. For bis(imino)pyridyl–Co(II) and Ni(II) catalysts bearing the SO42− and NO3− counter‐anions, the low activities for ethylene oligomerization are in sharp contrast to those of their chloride analogues. Copyright © 2009 Society of Chemical Industry
Growth inhibition and cell cycle arrest in the G0/G1 by schizandrin, a dibenzocyclooctadiene lignan isolated from Schisandra chinensis, on T47D human breast cancer cells
Authors: Kim Sun‐Jack , Min Hye‐Young , Lee Eun Jin , Kim Yeong Shik , Bae KiHwan , Kang Sam Sik , Lee Sang Kook
Published: July 2009

Schizandrin is one of the main dibenzocyclooctadiene lignans present in the fruit of Schisandra chinensis (Schisandraceae). Biological activities including hepatoprotective, antiviral and neuroprotective effects of schizandrin and other dibenzocyclooctadiene lignans have been reported previously. However, the antiproliferative effect of schizandrin against human cancer cells has been poorly determined to date. This study examined the antiproliferative effect of schizandrin in human breast cancer cells. Schizandrin exhibited growth inhibitory activities in cultured human breast cancer cells, and the effect was the more profound in estrogen receptor (ER)‐positive T47D cells than in ER‐negative MDA‐MB‐231 cells. When treated with the compound in T47D cells, schizandrin induced the accumulation of a cell population in the G0/G1 phase, which was further demonstrated by the induction of CDK inhibitors p21 and p27 and the inhibition of the expression of cell cycle checkpoint proteins including cyclin D1, cyclin A, CDK2 and CDK4. These results suggest that schizandrin inhibits cell proliferation through the induction of cell cycle arrest with modulating cell cycle‐related proteins in human breast cancer cells. Copyright © 2009 John Wiley & Sons, Ltd.
The neuropsychopharmacological effects of Catha edulis in mice offspring born to mothers exposed during pregnancy and lactation
Authors: Bedada Worku , Engidawork Ephrem
Published: July 2009

Chewing fresh leaves of the khat plant (Catha edulis Forsk) is a deep rooted and widespread habit in East Africa and the Middle East. Although a body of knowledge exists about the adverse effects of khat during pregnancy, data are sparse with regard to the consequences of long‐term exposure during pregnancy and lactation. The present work, therefore, was initiated to evaluate the neuropsychopharmacological effects of Catha edulis exposure during pregnancy and lactation in mice at postnatal day 28. To this effect, a lyophilized extract of khat (100 mg/kg, K100 and 200 mg/kg, K200), amphetamine (1 mg/kg, positive control, AMP), and a similar volume of 2% v/v Tween‐80 in distilled water (negative control, CONT) were administered daily to pregnant mice from gestational day 6 until weaning. Neuropsychopharmacological measurements were done by making use of a battery of neurobehavioural and cognitive tests. Moreover, toxicity to liver and kidney was also evaluated by determining biochemical markers for possible tissue damage.

K200 produced significant motor in‐coordination and emotional instability; as revealed by impairment in both cliff avoidance (p < 0.01) and forelimb grip strength (p < 0.001), as well as by an increase in stereotyped behaviour such as grooming (p < 0.05), and in the percent of time spent in open arms (p < 0.05). On the other hand, K100 had an effect only on grip strength where a decrement was noted (p < 0.01). A different pattern emerged with AMP whilst it increased duration of sniffing (p < 0.05), neither grip strength nor the time spent in the open arm was affected compared with CONT. Increased latency to reach the goal box and the number of wrong decisions (p < 0.05) in both the learning and the recall tests was observed with K200 and AMP. By contrast, both doses of khat and AMP equally affected performance in the Y‐maze (p < 0.05). Alterations in the biochemical indices of liver and kidney function were also noted with AMP and K200. These findings indicate that khat exposure produces dose‐related central and peripheral effects during pregnancy and lactation which might pose a serious impediment to the physical and mental development of the offspring. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamic Rheological and Thermal Properties of Acetylated Sweet Potato Starch
Authors: Lee Hye‐Lin , Yoo Byoungseung
Published: July 2009

Dynamic rheological and thermal properties of acetylated sweet potato starch (SPS) pastes (5%, w/w) were evaluated as a function of the degree of substitution (DS). The transition temperatures (To, Tp and Tc) and enthalpy of gelatinization (ΔH) of acetylated SPS, which were determined using differential scanning calorimetry, were lower than those of native starch, and significantly decreased with an increase in DS. Magnitudes of storage modulus (G′), loss modulus (G′′) and complex viscosity (η*) of acetylated SPS pastes were determined using a small‐deformation oscillatory rheometer. Dynamic moduli (G′, G′′ and η*) values of acetylated SPS pastes except for 0.123 DS were higher than those of native starch, and they also decreased with an increase in DS. The tan δ (ratio of G′′/G′) values (0.37–0.39) of acetylated SPS samples were lower than that (0.44) of native starch and no significant differences were found among acetylated SPS samples, indicating that the elastic properties of SPS pastes were affected by acetylation but did not depend on DS. The G′ values of acetylated SPS during aging at 4°C for 10 h were much lower than those of native starch, showing that the addition of acetyl groups produced a pronounced effect on the retrogradation properties of SPS.
Determination of trace elements in natural water using X‐ray fluorescence spectrometry after preconcentration with powdered silica gel
Authors: Yamini Y. , Amiri N. , Karimi M.
Published: July 2009

A simple and cheap method is described for simultaneous determination of V, Cr, Mn, Fe, Co, Ni, Cu and Zn contents in water by means of wavelength‐dispersive X‐ray fluorescence (WDXRF) spectrometry after preconcentration. The method of preconcentration is based on sorbing analytes onto silica gel powder. 1‐(2‐pyridylazo)‐2‐naphthol (PAN) is used as a chelating agent. The effect of some parameters such as pH, temperature, stirring time, amount of ligand, breakthrough volume and the limit of detection has been studied. The detection limits 0.120, 9.75 × 10−4, 0.075, 0.070, 0.061, 0.089, 0.029 and 0.044 mg l−1 were achieved for V, Cr, Mn, Fe, Co, Ni, Cu and Zn, respectively. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of Substructures on the Spreading Ability and Hydrolysis Resistance of Double‐Tail Trisiloxane Surfactants
Authors: Peng Zhongli , Lu Caifeng , Xu Minling
Published: July 2009

Four types of novel double‐tail trisiloxane surfactants of the general formula Me3SiOSiMeR1OSiMe3 (R1 = –(CH2)3NR2CH2CH(OH)CH2(OCH2CH2)xOCH3; R2 = –CH2CH(OH)CH2OCH2(CH2)yCH3, –CH2(CH2)3CH3, –CH2CH2CH(CH3)2; x = 8.4, 12.9, 17.5, 22; y = 2, 6), have been synthesized. Their structures were characterized by proton and carbon nuclear magnetic resonance. Most of them are able to reduce the surface tension of water to less than 24 mN/m at concentration levels of 10−5 mol/L and 10−4 mol/L. The emphasis was on the influence of substructures on their spreading ability and hydrolysis resistance. The results showed that a weaker hydrophilicity of a surfactant molecule, a larger molar ratio of methyl to methylene in the whole hydrophobic groups, more flexible hydrophobic groups and introduction of a methyl group in the spacer can all improve the spreading ability of the double‐tail trisiloxane surfactant solutions on low‐energy solid surfaces. The double‐tail trisiloxane surfactants 1F and 2F are stable for more than 270 days in a neutral environment (pH 7.0). The hydrolysis resistance of the double‐tail trisiloxane surfactants can be improved by a weaker hydrophilicity of the surfactant molecule, and a larger volume of the hydrophobic groups.
DE FINETTI ON RISK AVERSION
Authors: Kadane Joseph B. , Bellone Gaia
Published: July 2009

According to Mark Rubinstein (2006) ‘In 1952, anticipating Kenneth Arrow and John Pratt by over a decade, he [de Finetti] formulated the notion of absolute risk aversion, used it in connection with risk premia for small bets, and discussed the special case of constant absolute risk aversion.’ The purpose of this note is to ascertain the extent to which this is true, and at the same time, to correct certain minor errors that appear in de Finetti's work.
Multi-bump nodal solutions for an indefinite non-homogeneous elliptic problem
Authors: Girão Pedro M. , Gomes José Maria
Published: July 2009

We construct multi-bump nodal solutions of the elliptic equation

in $H^1_0(\varOmega)$, when μ is large, under appropriate assumptions, for f superlinear and subcritical and such that the eigenvalues of the associated linearized operator on $H^1_0(\{x\in\varOmega:a(x)>0\})$ at zero, u ↦ u − λ(−Δ)−1(a+u), are positive. The solutions are of least energy in some Nehari-type set defined by imposing suitable conditions on orthogonal components of functions in $H^1_0(\varOmega)$.
Articulation rate across dialect, age, and gender
Authors: Jacewicz Ewa , Fox Robert A. , O'Neill Caitlin , Salmons Joseph
Published: July 2009

Whether some languages or dialects are spoken faster or slower than others constitutes a gap in the understanding of sociolinguistic variation. Speech tempo is interconnected with the social, physical and psychological marking of speech. This study examines regional variation in articulation rate and its manifestations across speaker age, gender, and speaking situations (reading vs. informal talk). The results of an experimental investigation show that articulation rate differs significantly between two regional varieties of American English examined here. A group of Northern speakers (from Wisconsin) spoke significantly faster than a group of Southern speakers (from North Carolina). With regard to age and gender, young adults read faster than older adults in both regions; in informal talks, however, only Northern young adults spoke faster than older adults. Effects of gender were smaller and less consistent; men generally spoke slightly faster than women did. As the body of work on the sociophonetics of American English continues to grow in scope and depth, we argue that it is important to include fundamental phonetic information as part of our catalog of regional differences and patterns of change in American English.
Seven years of postseismic deformation following the 1999, M = 7.4 and M = 7.2, Izmit‐Düzce, Turkey earthquake sequence
Authors: Ergintav S. , McClusky S. , Hearn E. , Reilinger R. , Cakmak R. , Herring T. , Ozener H. , Lenk O. , Tari E.
Published: July 2009

We report the results of nearly 7 years of postseismic deformation measurements using continuously recorded and survey mode GPS observations for the 1999 Izmit‐Düzce earthquake sequence. Resolvable, time‐dependent postseismic changes to the preearthquake interseismic velocity field extend at least as far as the continuous GPS station in Ankara, ∼200 km southeast of the Izmit rupture. Seven years after the earthquake sequence, the relative postseismic velocity across the North Anatolian Fault (NAF) reaches ∼10–12 mm/a, roughly 50% of the steady state interseismic rate, with the highest postseismic velocities within 40 km of the coseismic ruptures. We use a sequence of logarithmic time functions to fit GPS site motions. Up to three logarithmic terms with decay constants of 1, 150, and 3500 days are necessary to fit all the transient motion observed at the continuous GPS stations. The first term is required for the component of site motion parallel to the NAF at near‐field sites strongly implicating rapid, shallow afterslip. The intermediate and longer‐term postseismic velocity components reflect more broadly distributed strain with a symmetric double‐couple pattern suggestive of either localized, deep afterslip or viscoelastic relaxation of the upper mantle and/or lower crust. In two areas (including the Marmara Sea) this pattern is superimposed on north‐south extension centered on the NAF. We speculate that this extension may result from aseismic dip slip along coseismically weakened faults, driven by the background tectonic stress.
Anelastic Earth structure from the coherency of the ambient seismic field
Authors: Prieto G. A. , Lawrence J. F. , Beroza G. C.
Published: July 2009

Cross correlation of the ambient seismic field is now routinely used to measure seismic wave travel times; however, relatively little attention has been paid to other information that could be extracted from these signals. In this paper we demonstrate the relationship between the spatial coherency of the ambient field and the elastodynamic Green's function in both time and frequency domains. Through measurement of the frequency domain coherency as a function of distance, we sequentially recover phase velocities and attenuation coefficients. From these measurements we generate 1‐D shear wave velocity and attenuation models for southern California. The ambient field measurements of attenuation and the exceptional path coverage that results from the many possible interstation measurements allow us to extend Q estimates over a range of frequencies that has previously been difficult to analyze using earthquake data. Measurements from paths that cross major sedimentary basins show both lower wave speeds and lower‐quality factors than other paths, as expected. Our results indicate that there is a wealth of information available in the spatial coherency of the ambient seismic field.
Stabilizing effect of random waves on rip currents
Authors: Hasan Haider , Dodd Nicholas , Garnier Roland
Published: July 2009

The instability leading to the formation of rip currents in the nearshore for normal waves on a nonbarred, nonerodible beach is examined with a comprehensive linear stability numerical model. In contrast to previous studies, the hypothesis of regular waves has been relaxed. The results obtained here point to the existence of a purely hydrodynamical positive feedback mechanism that can drive rip cells, which is consistent with previous studies. This mechanism is physically interpreted and is due to refraction and shoaling. However, this mechanism does not exist when the surf zone is not saturated because negative feedback provided by increased (decreased) breaking for positive (negative) wave energy perturbations overwhelms the shoaling/refraction mechanism. Moreover, turbulent Reynolds stress and bottom friction also cause damping of the rip current growth. All the nonregular wave dissipations examined give rise to these hydrodynamical instabilities when feedback onto dissipation is neglected. When this feedback is included, the dominant effect that destroys these hydrodynamical instabilities is the feedback of the wave energy onto the dissipation. It turns out that this effect is strong and does not allow hydrodynamical instabilities on a planar beach to grow for random seas.
Demonstration of ocean surface salinity microwave measurements from space using AMSR‐E data over the Amazon plume
Authors: Reul N. , Saux‐Picart S. , Chapron B. , Vandemark D. , Tournadre J. , Salisbury J.
Published: July 2009

Microwave Sea Surface Salinity (SSS) measurements can be performed by isolating the emissivity response to salinity changes from numerous geophysical effects, including surface temperature and wind waves. At L‐band frequencies (1 to 2 GHz), the sensitivity to SSS is sufficient but it falls off quickly as frequency is increased. Nevertheless, methods using higher microwave frequencies with much lower SSS sensitivity than at L band, can already be tested. In particular, combining 6 and 10 GHz data in vertical polarization efficiently minimizes sea surface roughness and thermal impacts. Using AMSR‐E data, the retrieved bi‐monthly maps of SSS at 0.5° resolution over the region of the Amazon plume show relative accuracy in‐line with the future L‐band dedicated mission objectives.
Digital microfluidics on a wire
Authors: Gilet T. , Terwagne D. , Vandewalle N.
Published: July 2009

In this letter, we discuss the behavior of droplets on fiber networks. An on/off transition is observed when a droplet comes around an intersection between several fibers: large droplets cross the junction while small droplets remain pinned. We show that fibers perform advantageously most operations of digital microfluidics, such as multiplexed biochemical microreactions: intersections are the basic component of fiber-based microfluidic devices.