bluuebunny/crossref_metadata_2025 huggingface dataset:
Nd‐Doped TiO2 Nanorods: Preparation and Application in Dye‐Sensitized Solar Cells
Authors: Yao Qiaohong , Liu Junfeng , Peng Qing , Wang Xun , Li Yadong
Published: October 2006

Monodispersed Nd‐doped TiO2 nanorods (20 nm×2 nm) were synthesized by solvothermal methods and characterized by TEM, XRD, and EDS. Application of the nanorods for modifying conventional photoanodes in dye‐sensitized solar cells (DSSCs) was investigated. Data show that, after modification, an enhancement of the incident‐photon‐to‐current conversion efficiency (IPCE) in the whole range of visible light was observed and an increase of 33.3 % for overall conversion efficiency was achieved. Our mechanistic proposal is that Nd ions doped on TiO2 nanorods to some extent enhance the injection of excited electrons and decrease the recombination rate of the injected electrons.
Improved catalytic properties of immobilized lipases by the presence of very low concentrations of detergents in the reaction medium
Authors: Fernandez‐Lorente Gloria , Palomo Jose M. , Cabrera Zaida , Fernandez‐Lafuente Roberto , Guisán José M.
Published: October 2006

The addition of a very small concentration of a detergent (in many instances under the critical micellar concentration (cmc)) has been found to greatly increase the activity of immobilized lipases, using those from Pseudomonas fluorescens (PFL) and Candida antarctica (isoform B) as model enzymes. However, the detergents may also have a negative effect on enzyme activity; in fact, for all enzyme preparations and substrates the activity/detergent concentration curve reached a maximum value and started to decrease, in many instances even under the initial value. The concentration and nature of the detergent (SDS, CTAB, Triton X‐100, or X‐45) that permitted the maximum hyperactivation was different depending on the substrate. The best hyperactivation values promoted by the presence of detergent were over a 20‐fold factor. The presence of detergents permitted the inhibition of lipases by irreversible covalent inhibitors (e.g., 4‐(2‐aminoethyl)benzenesulfonyl fluoride hydrochloride) (AEBSF) while the enzyme, in the absence of detergent, is not inhibited by these irreversible inhibitors. This suggested that the main effect of the detergents is to shift the conformational equilibrium of lipases toward the open form. Moreover, the presence of detergents also permitted to improve the enantioselectivity exhibited by the immobilized lipases in some cases. For example, the enantioselectivity of PFL‐glyoxyl agarose increased from 40 to more than 100 in the hydrolysis of (±)‐2‐hydroxy‐4‐phenylbutyric acid ethyl ester by using 0.1% CTAB. Biotechnol. Bioeng. 2007;97: 242–250. © 2006 Wiley Periodicals, Inc.
Optimization of enzyme complexes for lignocellulose hydrolysis
Authors: Berlin Alex , Maximenko Vera , Gilkes Neil , Saddler Jack
Published: October 2006

The ability of a commercial Trichoderma reesei cellulase preparation (Celluclast 1.5L), to hydrolyze the cellulose and xylan components of pretreated corn stover (PCS) was significantly improved by supplementation with three types of crude commercial enzyme preparations nominally enriched in xylanase, pectinase, and β‐glucosidase activity. Although the well‐documented relief of product inhibition by β‐glucosidase contributed to the observed improvement in cellulase performance, significant benefits could also be attributed to enzymes components that hydrolyze non‐cellulosic polysaccharides. It is suggested that so‐called “accessory” enzymes such as xylanase and pectinase stimulate cellulose hydrolysis by removing non‐cellulosic polysaccharides that coat cellulose fibers. A high‐throughput microassay, in combination with response surface methodology, enabled production of an optimally supplemented enzyme mixture. This mixture allowed for a ∼twofold reduction in the total protein required to reach glucan to glucose and xylan to xylose hydrolysis targets (99% and 88% conversion, respectively), thereby validating this approach towards enzyme improvement and process cost reduction for lignocellulose hydrolysis. Biotechnol. Bioeng. 2007;97: 287–296. © 2006 Wiley Periodicals, Inc.
Anaerobic digestion of solid material: Multidimensional modeling of continuous‐flow reactor with non‐uniform influent concentration distributions
Authors: Vavilin V.A. , Lokshina L.Y. , Flotats X. , Angelidaki I.
Published: October 2006

A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non‐uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous‐flow anaerobic digestion. Batch experiments reported and simulated earlier by Vavilin and Angelidaki (2005) were used to modernize a kinetic scheme and to obtain the corresponding kinetic coefficients. In the new models, hydrolytic microorganisms were included using Contois kinetics for the hydrolysis/acidogenesis degradation of municipal solid waste (MSW). Monod kinetics was applied for description of methanogenesis. Both hydrolytic and methanogenic microorganisms were assumed to be inhibited by high volatile fatty acids (VFA) concentration. According to the new distributed models, the mixing level reduction expressed by increasing dimensionless Peclet number may improve the continuous flow reactor performance at the relatively low influent methanogenic biomass concentration. In the continuously stirred tank reactor (CSTR) there are two steady states with and without methane production at slightly different values of initial methanogenic biomass concentration. In the system, the threshold methanogenic biomass concentration existed because of inhibition by high VFA concentration. High methanogenic biomass concentration is required for efficient anaerobic digestion of MSW in order to avoid possible inhibition due to high VFA build‐up. Thus, CSTR configuration might have unstable dynamics at high organic loading as shown in earlier experiments carried out by Stroot et al. (2001). A gradual increase of organic loading during the start up of a completely mixed digester causing an accumulation of methanogenic biomass is a solution to prevent a probable digester failure. According to the distributed models a plug‐flow reactor with non‐uniform influent concentration distributions where methanogenic and hydrolytic microorganisms are separated has significant methane production and solids removal at the relatively low influent methanogenic biomass concentration. Biotechnol. Bioeng. 2007;97: 354–366. © 2006 Wiley Periodicals, Inc.
Factors Mediating Activity, Selectivity, and Substrate Specificity for the Thiamin Diphosphate‐Dependent Enzymes Benzaldehyde Lyase and Benzoylformate Decarboxylase
Authors: Knoll Michael , Müller Michael , Pleiss Jürgen , Pohl Martina
Published: October 2006

Benzaldehyde lyase from Pseudomonas fluorescens and benzoylformate decarboxylase from Pseudomonas putida are homologous thiamin diphosphate‐dependent enzymes that catalyze carboligase and carbolyase reactions. Both enzymes catalyze the formation of chiral 2‐hydroxy ketones from aldehydes. However, the reverse reaction has only been observed with benzaldehyde lyase. Whereas benzaldehyde lyase is strictly R specific, the stereoselectivity of benzoylformate decarboxylase from P. putida is dependent on the structure and orientation of the substrate aldehydes. In this study, the binding sites of both enzymes were investigated by using molecular modelling studies to explain the experimentally observed differences in the activity, stereo‐ and enantioselectivity and substrate specificity of both enzymes. We designed a detailed illustration that describes the shape of the binding site of both enzymes and sufficiently explains the experimental effects observed with the wild‐type enzymes and different variants. These findings demonstrate that steric reasons are predominantly responsible for the differences observed in the (R)‐benzoin cleavage and in the formation of chiral 2‐hydroxy ketones.
SECM Visualization of Spatial Variability of Enzyme‐Polymer Spots. Part 2: Complex Interference Elimination by Means of Selection of Highest Sensitivity Sensor Substructures and Artificial Neural Networks
Authors: Maciejewska Monika , Schäfer Dominik , Schuhmann Wolfgang
Published: October 2006

Polymer spots with entrapped glucose oxidase were fabricated on glass surfaces and the localized enzymatic response was subsequently visualized using scanning electrochemical microscopy (SECM) in the generator–collector mode. SECM images were obtained under simultaneous variation of the concentration of glucose (0–6 mM) and ascorbic acid (0–200 μM), or, in a second set of experiments, of glucose (0–2 mM) and 2‐deoxy‐D(+)‐glucose (0–4 mM). Aiming at the quantification of the mixture components discretization of the response surfaces of the overall enzyme/polymer spot into numerous spatially defined microsensor substructures was performed. Sensitivity of sensor substructures to measured analytes was calculated and patterns of variability in the data were analyzed before and after elimination of interferences using principal component analysis. Using artificial neural networks which were fed with the data provided by the sensor substructures showing highest sensitivity for glucose, glucose concentration could be calculated in solutions containing unknown amounts of ascorbic acid with a good accuracy (RMSE 0.17 mM). Using, as an input data set, measurements provided by sensing substructures showing highest sensitivity for ascorbic acid in combination with the response of the sensors showing highest dependence on the glucose concentration, the error of the ascorbic acid concentration calculation in solution containing the unknown amount of glucose was 10 μM. Similarly, prediction of the glucose concentration in the presence of 2‐deoxy‐D(+)‐glucose was possible with a RMSE of 0.1 mM while the error of the calculation of 2‐deoxy‐D(+)‐glucose concentrations in the presence of unknown concentrations of glucose was 0.36 mM.
QCM Immunosensor Based on Polyamidoamine Dendrimers
Authors: Svobodová Lenka , Šnejdárková Maja , Polohová Vladimíra , Grman Igor , Rybár Peter , Hianik Tibor
Published: October 2006

The poly(amidoamine)(PAMAM) dendrimers of fourth generation (G4) and 1‐hexadecanethiol (HDT) has been used for formation of self assembled monolayers on a gold surface for preparation of quartz crystal microbalance (QCM) immunosensor for detection of human IgG. The anti‐IgG antibodies were immobilized on a surface of G4‐HDT layers or those covered by Protein A. In later case the oriented immobilization of anti‐IgG takes place due to preferred interaction of Fc portion of antibodies with the Protein A. The detection limit in a flow mode was 7 nM both for biosensor with and without Protein A. However, in the case of Protein A the number of bounded Ab was 1.4 times lower in comparison with those without Protein A. Thus, the sensitivity of the Protein A based sensor was higher due to orientation effect in comparison with randomly oriented Ab at a dendrimer surface without Protein A. Increased concentration of IgG and formation of Ab‐Ag complexes resulted in increase of motional resistance, that suggest increased contribution of viscoelasticity, as revealed from impedance analysis. The most important property of the immunosensor was its ability for regeneration using 0.1 M glycine‐HCl.
Electrostatic Assemblies for Bioelectrocatalytic and Bioelectronic Applications
Authors: Domínguez Elena , Suárez Guillaume , Narváez Arántzazu
Published: October 2006

This work extensively covers the use of layer‐by‐layer (LbL) assembly of polyelectrolytes for the transduction of catalytic and affinity events. It is demonstrated that by controlling the charge of polyelectrolytes, electrostatic interactions drive then the LbL construction of supramolecular architectures with improved performance. Particularly, by adequately charging an osmium based redox polymer, a multicofactor protein (fructose dehydrogenase) may be deposited in a favored orientation resulting in a more efficient electrochemical communication. A H2O2 transducing interface is created by the enhancement of electrostatic interactions between the electrochemical and catalytic layer. Further assemblies include the coupling of an oxidase (alcohol oxidase) with the H2O2 transducing interface resulting in a linear increase of current with the number of AOX layers. Finally, affinity assemblies are demonstrated by deposition of anti Dexamethasone antibodies. Faraday currents are then obtained by the electrochemical communication between the HRP labeled immunoconjugate and the electrochemical interface in a heterogeneous competitive assay format.
Suppression of cell proliferation, induction of apoptosis and cell cycle arrest: Chemopreventive activity of vanadium in vivo and in vitro
Authors: Ray Rajarshi Sankar , Ghosh Balaram , Rana Ajay , Chatterjee Malay
Published: October 2006

In the present study, the authors evaluated the anticancer mechanism of vanadium, a dietary micronutrient and an important pharmacological agent, on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF7 in vitro. Female Sprague‐Dawley rats were treated with 7,12‐dimethylbenz(α)anthracene (0.5 mg/100 g body weight) by a single tail vein injection in an oil emulsion to induce mammary preneoplasia. Vanadium (ammonium monovanadate) at a concentration of 0.5 ppm (4.27 μmol/l) was supplemented in drinking water and given ad libitum to the experimental groups for 24 weeks. Histological finding showed substantial repair of hyperplastic lesions. There was a significant reduction in incidence, multiplicity (34%, p < 0.01), size of palpable mammary tumors and delay in mean latency period of tumor appearance. Immunohistochemical analysis in vivo indicated a decrease in cell proliferation (24.68% p < 0.05) and an increase among the TUNEL‐positive apoptotic cells along with strong expressions of p53 and Bax, and downregulation of Bcl2 proteins in the mammary tissue of vanadium‐treated animals. Further, MCF7 cells were cultured in minimal essential medium and were treated with 100, 175 and 250 μM of vanadium (ammonium monovanadate) for 36 hr. Exposure of MCF7 cells to vanadium led to induction of apoptosis in a dose‐dependent manner. It was found further that vanadium treatment brought about a prominent cell cycle arrest and chromosomal condensation, leading to apoptosis (42.62%, p < 0.05). Results of both the in vivo and in vitro study demonstrate that vanadium has the potential to be developed into an anti‐breast cancer drug in the near future. © 2006 Wiley‐Liss, Inc.
Polydimethylsiloxane as a substrate for retinal pigment epithelial cell growth
Authors: Krishna Yamini , Sheridan Carl M. , Kent David L. , Grierson Ian , Williams Rachel L.
Published: October 2006

Retinal pigment epithelial (RPE) cell transplantation represents potential treatment for age‐related macular degeneration (AMD). Because delivery of isolated cells can cause serious complications, it is necessary to develop a suitable transplant membrane that could support an intact functioning RPE monolayer. Polydimethylsiloxane (PDMS) possesses the physical properties required for a transplanting device and is widely used clinically. We have investigated the use of PDMS as a potential surface for the growth of healthy RPE monolayers. PDMS discs were surface modified by air and ammonia gas plasma treatments. Dynamic contact angles were measured to determine the changes in wettability. Human ARPE‐19 cells were seeded onto untreated and treated samples. Cell number, morphology and monolayer formation, cytotoxicity, and phagocytosis of photoreceptor outer segments (POS) were assessed at set time‐points. Air plasma treatment increased the wettability of PDMS. This significantly enhanced cell growth, reaching confluence by day 7. Immunofluorescence revealed well‐defined actin staining, monolayer formation, and high cell viability on air plasma treated and untreated surfaces, and to a lesser extent, on ammonia plasma treated. Furthermore, RPE monolayers were able to demonstrate phagocytosis of POS in a time‐dependent manner similar to control. PDMS can support an intact functional monolayer of healthy differentiated RPE cells. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Zeta‐potentials of alginate‐PLL capsules: A predictive measure for biocompatibility?
Authors: de Vos Paul , de Haan Bart J. , Kamps Jan A.A.M. , Faas Marijke M. , Kitano Toshio
Published: October 2006

Alginate‐poly‐L‐lysine (PLL) microencapsulation of cells is a promising approach to prevent rejection in the absence of immunosuppression. Clinical application, however, is hampered by insufficient insight in factors influencing biocompatibility of the capsules. By now, it has been accepted that not only the chemical composition of the materials applied but also other factors contribute to bioincompatibility. The zeta‐potential serves as a measure for the electrical charge of the surface and has been shown to be a predictive value for the interfacial reactions between the biomaterial and the surrounding tissue in other applications. In the present study, we have assessed the streaming potential of alginate‐PLL capsules composed of either low‐, intermediate‐, or high‐guluronic (G) alginate to calculate the zeta‐potential. The zeta‐potentials of the capsules were compared to the biological response against the capsules at 4 weeks after implantation in the rat. We show that high‐G and low‐G alginates provoke a more severe response in the rat than capsules prepared of intermediate‐G alginate. This correlates with a higher zeta‐potential of the high‐G and low‐G alginates and by a change in zeta‐potential at lower pH. These lower pH‐levels are common directly after implantation as the consequence of a host‐response associated with mandatory surgery. Our results suggest that we should not only consider the capsule properties under physiological circumstances to explain bioincompatibility but also the capsule features during common pathophysiological situations. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Endoglin increases eNOS expression by modulating Smad2 protein levels and Smad2‐dependent TGF‐β signaling
Authors: Santibanez Juan F. , Letamendia Ainhoa , Perez‐Barriocanal Fernando , Silvestri Cristoforo , Saura Marta , Vary Calvin P.H. , Lopez‐Novoa Jose M. , Attisano Liliana , Bernabeu Carmelo
Published: October 2006

The endothelial nitric oxide synthase (eNOS) is a critical regulator of cardiovascular homeostasis, whose dysregulation leads to different vascular pathologies. Endoglin is a component of the transforming growth factor beta (TGF‐β) receptor complex present in endothelial cells that is involved in angiogenesis, cardiovascular development, and vascular homeostasis. Haploinsufficient expression of endoglin has been shown to downregulate endothelium‐derived nitric oxide in endoglin+/− (Eng+/−) mice and cultured endothelial cells. Here, we find that TGF‐β1 leads to an increased vasodilatation in Eng+/+ mice that is severely impaired in Eng+/− mice, suggesting the involvement of endoglin in the TGF‐β regulated vascular homeostasis. The endoglin‐dependent induction of eNOS occurs at the transcriptional level and is mediated by the type I TGF‐β receptor ALK5 and its downstream substrate Smad2. In addition, Smad2‐specific signaling is upregulated in endoglin‐induced endothelial cells, whereas it is downregulated upon endoglin gene suppression with small interference RNA (siRNA). The endoglin‐dependent upregulation of Smad2 was confirmed using eNOS and pARE promoters, whose activities are known to be Smad2 dependent, as well as with the interference of Smad2 with siRNA, Smurf2, or a dominant negative form of Smad2. Furthermore, increased expression of endoglin in endoglin‐inducible endothelial cells or in transfectants resulted in increased levels of Smad2 protein without affecting the levels of Smad2 mRNA. The increased levels of Smad2 appear to be due to a decreased ubiquitination and proteasome‐dependent degradation leading to stabilization of Smad2. These results suggest that endoglin enhances Smad2 protein levels potentiating TGF‐β signaling, and leading to an increased eNOS expression in endothelial cells. J. Cell. Physiol. 210: 456–468, 2007. © 2006 Wiley‐Liss, Inc.
Noninvasive three‐dimensional assessment of femoroacetabular impingement
Authors: Tannast Moritz , Kubiak‐Langer Monika , Langlotz Frank , Puls Marc , Murphy Stephen B. , Siebenrock Klaus A.
Published: October 2006

A CT‐based method (“HipMotion”) for the noninvasive three‐dimensional assessment of femoroacetabular impingement (FAI) was developed, validated, and applied in a clinical pilot study. The method allows for the anatomically based calculation of hip range of motion (ROM), the exact location of the impingement zone, and the simulation of quantified surgical maneuvers for FAI. The accuracy of HipMotion was 0.7 ± 3.1° in a plastic bone setup and −5.0 ± 5.6° in a cadaver setup. Reliability and reproducibility were excellent [intraclass correlation coefficient (ICC) > 0.87] for all measures except external rotation (ICC = 0.48). The normal ROM was determined from a cohort of 150 patients and was compared to 31 consecutive hips with FAI. Patients with FAI had a significantly decreased flexion, internal rotation, and abduction in comparison to normal hips (p < 0.001). Normal hip flexion and internal rotation are generally overestimated in a number of orthopedic textbooks. HipMotion is a useful tool for further assessment of impinging hips and for appropriate planning of the necessary amount of surgical intervention, which represents the basis for future computer‐assisted treatment of FAI with less invasive surgical approaches, such as hip arthroscopy. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:122–131, 2007
Fatal Gvhd As A Complication of Liver Transplantation for Undetermined Fulminant Hepatic Failure and Associated Aplastic Anemia
Authors: Schäppi Michela G. , Belli Dominique C. , Rimensberger Peter C. , Chardot Christophe , Kaya Gürkan , Tiercy Jean-Marie , Ozsahin Hulya
Published: October 2006

Fulminant hepatic failure of unknown origin is the most common cause of fulminant hepatitis with high incidence of aplastic anaemia. Furthermore, the association of liver failure and aplastic anaemia has an increased mortality rate. In this report we describe a 16-month-old boy who presented with aplastic anaemia preceding a non-A, non-B, non-C fulminant liver failure. He developed severe graft versus host disease (GvHD) after liver transplantation, proven by the presence of donor cells in the peripheral blood and in the skin biopsy. He received conventional therapy (steroids, mycophenolate, anti-IL-2 monoclonal antibodies, anti-thymocyte globulin) without success. In an attempt to obtain T cell depletion and reduce the GvHD, he was treated with Alemtuzumab, a first time use for this indication. Aplastic anaemia was extensively investigated, especially exploring the possibility of primary immunodeficiency and reticular dysgenesis which were excluded based on clinical history. However, another form of primary immunodeficiency could be the cause of the uncontrollable proliferation of the donor lymphocytes derived from the liver transplant. Despite aggressive treatment GvHD progressed and the patient died of multiorgan failure. The majority of authors mention aplastic anaemia as a secondary event post liver transplant, whereas in our view this might be a haematopoietic stem cell disorder preceding fulminant hepatic failure. These patients also need to be evaluated extensively in order to exclude a primary immunodeficiency. The underlying disease will determine the choice of immunosuppressive treatment, especially in case of development of GvHD caused by the transplanted lymphocytes inhabiting the donor liver.
Liver Transpl 12:1693–1697, 2006.

© 2006 AASLD.
L1, β1 integrin, and cadherins mediate axonal regeneration in the embryonic spinal cord
Authors: Blackmore Murray , Letourneau Paul C.
Published: October 2006

Embryonic birds and mammals are capable of axon regeneration after spinal cord injury, but this ability is lost during a discrete developmental transition. We recently showed that changes within maturing neurons, as opposed to changes solely in the spinal cord environment, significantly restrict axon regeneration during development. The developmental changes within neurons that limit axon regeneration remain unclear. One gap in knowledge is the identity of the adhesive receptors that embryonic neurons use to extend axons in the spinal cord. Here we test the roles of L1/NgCAM, β1 integrin, and cadherins, using a coculture system in which embryonic chick brainstem neurons regenerate axons into an explant of embryonic spinal cord. By in vivo and in vitro methods, we found that brainstem neurons reduce axonal expression of L1 as they mature. Disrupting either L1 or β1 integrin function individually in our coculture system partially inhibited growth of brainstem axons in spinal cords, while disrupting cadherin function alone had no effect. However, when all three adhesive receptors were blocked simultaneously, axon growth in the spinal cord was reduced by 90%. Using immunohistochemistry and in situ hybridization we show that during the period when neurons lose their regenerative capacity they reduce expression of mRNA for N‐cadherin, and reduce axonal L1/NgCAM protein through a post‐transcriptional mechanism. These data show that embryonic neurons use L1/NgCAM, β1 integrin, and cadherin receptors for axon regeneration in the embryonic spinal cord, and raise the possibility that a reduced expression of these essential receptors may contribute to the low‐regenerative capacity of older neurons. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Singing, but not seizure, inducessynaptotagmin IVin zebra finch song circuit nuclei
Authors: Poopatanapong A. , Teramitsu I. , Byun J.S. , Vician L.J. , Herschman H.R. , White S.A.
Published: October 2006

Synaptotagmins are a family of proteins that function in membrane fusion events, including synaptic vesicle exocytosis. Within this family,synaptotagmin IV(Syt IV) is unique in being a depolarization‐induced immediate early gene (IEG). Experimental perturbation ofSyt IVmodulates neurotransmitter release in mice, flies, and PC12 cells, and modulates learning in mice. Despite these features, induction ofSyt IVexpression by a natural behavior has not been previously reported. We used the zebra finch, a songbird species, to investigateSyt IVbecause song is a naturally learned behavior whose neuroanatomical basis is largely identified. We observed that, similar to rodents,Syt IVis inducible in songbirds. This induction was selective and depended on the nature of neuronal depolarization. Generalized seizures caused by the GABAAreceptor antagonist, metrazole, induced the IEG,ZENK,in zebra finch brain. However, these same seizures failed to induceSyt IVin song control areas. In contrast, when nontreated birds sang, three song control areas showed strikingSyt IVinduction. Further, this induction appeared sensitive to the social context in which song was sung. Together, these data suggest that neural activity during singing can driveSyt IVexpression within song circuitry whereas generalized seizure activity fails to do so even though song control areas are depolarized. Our findings indicate that, within this neural circuit for a procedurally learned sensorimotor behavior,Syt IVis selective and requires precisely patterned neural activity and/or neuromodulation associated with singing. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
A coagulation factor VII deficiency protects against acute inflammatory responses in mice
Authors: Xu H , Ploplis VA , Castellino FJ
Published: October 2006

Upregulation of the activated Factor VII (FVIIa)/Tissue Factor complex, downregulation of natural anticoagulation pathways, and inhibition of fibrinolysis, are major contributors to coagulopathies associated with acute inflammation. Provision of FVIIa, and consequent downstream coagulation‐related proteases, also stimulates further inflammatory changes, which can result in disseminated intravascular coagulation. Thus, the potential protective effects in vivo of a genetic‐based reduction in FVII levels have been investigated in a murine model of acute inflammation, namely lipopolysaccharide (LPS)‐induced lethal endotoxaemia. Mice with a total FVII deficiency do not survive the neonatal period. Therefore mice expressing low levels of FVII (FVIItTA/tTA), producing sufficient amounts of FVII for survival (approximately 5% of wild‐type (WT) FVII), were employed to investigate in vivo pathways involved in the crosstalk between coagulation, inflammation, and survival, consequent to administration of a lethal dose of LPS. The FVIItTA/tTA mice presented with reduced mortality, coagulation, and inflammatory responses in comparison with similarly treated WT mice after administration of LPS. The attenuated inflammatory responses in FVIItTA/tTA mice were associated with downregulation of Egr‐1 signalling. Administration, in vivo, of specific inhibitors of FXa and thrombin demonstrated that the inflammatory responses were unaltered in WT mice, but further reduced in FVIItTA/tTA mice. Therefore, a FVII deficiency enhances survival from lethal endotoxaemia both through attenuation of inflammatory responses that result directly from reduced FVIIa levels, and, indirectly, from downregulation of coagulation proteases downstream of the FVII‐dependent cascade. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthesis, characterization and properties of photoresponsive polymers comprising photocrosslinkable pendant chalcone moieties
Authors: Tamilvanan Muthusamy , Pandurangan Arumugam , Reddy Boreddy SR , Subramanian Kathavarayan
Published: October 2006

New methacrylate monomers, namely 4‐methacryloyloxyphenyl‐4′‐fluorostyryl ketone and 4‐methacryloyloxyphenyl‐4′‐ethylstyryl ketone comprising a free radical polymerizable group and a photocrosslinkable group, were synthesized by reacting the respective hydroxychalcones with methacryloyl chloride in the presence of triethylamine. The monomers were polymerized in the presence of ethyl methyl ketone (EMK) at 70 °C using benzoyl peroxide as the initiator. The chemical structures were characterized using various spectroscopic techniques: ultraviolet, Fourier transform infrared, 1H NMR and 13C NMR. The thermal stability of the polymers was studied using thermogravimetric analysis in nitrogen atmosphere. Differential scanning calorimetry was used to determine the glass transition temperature of the homopolymers. Photocrosslinking of the synthesized homopolymers was investigated in solution. The two homopolymers were crosslinked within 10–15 min. After crosslinking, the homopolymers were insoluble in the same solvent. Copyright © 2006 Society of Chemical Industry
Synthesis and characterization of ABS resin using in situ transferring from emulsion to suspension polymerization
Authors: Zhang Dalei , Luan Mingyue , Lin Quan , Gu Qiang , Cui Zhanchen , Yang Bai
Published: October 2006

A novel approach based on an emulsion in situ suspension polymerization process for synthesizing poly(acrylonitrile–butadiene–styrene) (ABS) resin is reported. Experimental results show that the reaction system can be transformed from an emulsion state to a suspension polymerization state steadily with the content of polybutadiene (PB) in the range 0–15 wt% in ABS resin. When PB is replaced by poly(styrene‐co‐butadiene) with the content of rubber particles being kept below 20 wt%, the emulsion system can be easily transferred to the suspension polymerization state through a process of latex coagulation in the forward direction, which means that the emulsion solution was dripped slowly into the suspension reaction system in the presence of coagulating agent. The dispersion status of the rubber particles in the ABS resin was studied using transmission electron microscopy, which indicated that the rubber particles were in a dispersed state in a continuous matrix of poly(styrene‐co‐acrylonitrile) when the content of rubber particles was below 20 wt%. The mechanical properties of the ABS resins obtained are as follows: elongation at break, 9.4–45.7%; yield tensile strength, 35.1–42.2 MPa; impact strength, 98.2–116.3 J m−1. Copyright © 2006 Society of Chemical Industry
Fine‐grained erbium‐doped strontium hexaferrite
Authors: Rezlescu N. , Doroftei C. , Rezlescu E. , Popa P. D.
Published: October 2006

In the present work the Er‐substituted Sr hexaferrite, SrFe12–x Erx O19, prepared by sol–gel self combustion and subsequent heat treatments, is investigated. The combusted powders were annealed at 800, 900 and 1000 °C for 5, 10, 20, 40, 80, 160 and 320 min. The influence of annealing temperature and time on the structure and magnetic properties (specific saturation magnetization M s, specific remanent magnetization M r and coercivity H c) is studied. The structural characterization was made using X‐ray diffraction and scanning electron microscopy. The magnetic measurements were carried out with a vibrating sample magnetometer. During the heat treatments the soft magnetic powder obtained by sol–gel self combustion is changed to a hard magnetic powder. The coercivity increases to a value much greater than its value before annealing. The remarkable increase of H c is explained by crystallization of the hard magnetic hexaferrite phase and corresponds to a transition from superparamagnetic to stable single‐domain particles, as a result of the grain growth during the heat treatment. The H c values of the samples heat treated for longer times (over 80 min) are fairly satisfactory. This means that the particle sizes were well under control to prevent abnormal growth of the particles. M s and M r depend on both annealing time and temperature. M s and M r begin to increase when H c sharply increases and tend to a constant value with increasing annealing time. Also, M s and M r decrease with increasing Er content. This dependence may be ascribed to the lowering of the total magnetic moment when Er3+ ions substitute magnetic Fe3+ ions in the M‐hexagonal structure or to the formation of more non‐magnetic phase like hematite, α‐Fe2O3. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Natural terrain classification using three‐dimensional ladar data for ground robot mobility
Authors: Lalonde Jean‐François , Vandapel Nicolas , Huber Daniel F. , Hebert Martial
Published: October 2006

In recent years, much progress has been made in outdoor autonomous navigation. However, safe navigation is still a daunting challenge in terrain containing vegetation. In this paper, we focus on the segmentation of ladar data into three classes using local threedimensional point cloud statistics. The classes are: “scatter” to represent porous volumes such as grass and tree canopy; “linear” to capture thin objects like wires or tree branches, and finally “surface” to capture solid objects like ground surface, rocks, or large trunks. We present the details of the proposed method, and the modifications we made to implement it on‐board an autonomous ground vehicle for real‐time data processing. Finally,we present results produced from different stationary laser sensors and from field tests using an unmanned ground vehicle. © 2006 Wiley Periodicals, Inc.
Neuroprotective effects of tetramethylpyrazine on hydrogen peroxide‐induced apoptosis in PC12 cells
Authors: Cheng Xin‐Rui , Zhang Li , Hu Juan‐Juan , Sun Lan , Du Guan‐Hua
Published: October 2006

In the present study, we investigated the effects of tetramethylpyrazine (TMP) on hydrogen peroxide (H2O2)‐induced apoptosis in PC12 cells. The apoptosis in H2O2‐induced PC12 cells was accompanied by a decrease in Bcl‐2/Bax protein ratio, release of cytochrome c to cytosol and the activation of caspase‐3. TMP not only suppressed the down‐regulation of Bcl‐2, up‐regulation of Bax and the release of mitochondrial cytochrome c to cytosol, but also attenuated caspase‐3 activation and eventually protected against H2O2‐induced apoptosis. These results indicated that TMP blocked H2O2‐induced apoptosis by the regulation of Bcl‐2 family members, suppression of cytochrome c release, and caspase cascade activation in PC12 cells.
Muscle actin isoforms are differentially expressed in human satellite cells isolated from donors of different ages
Authors: Lancioni Hovirag , Lucentini Livia , Palomba Antonella , Fulle Stefania , Micheli Maria Rita , Panara Fausto
Published: October 2006

Myogenesis is mainly sustained by a subpopulation of myogenic cells known as satellite cells (SC). In this paper we studied α‐smooth muscle (αSMA) and α‐sarcomeric muscle (αSRA) actin isoform expression in cultures of human satellite cells (HSC) isolated from skeletal muscle biopsies from a 5‐day‐old newborn, a 34‐year‐old young adult and a 71‐year‐old donor. Myogenicity of cultures was assessed using immunocytochemical detection of desmin and myosin heavy chain. Time‐course expression of αSRA and αSMA were studied with both immunocytochemistry and western blotting procedures. Although αSMA was never detected in whole skeletal muscle, both αSMA and αSRA were detected in proliferating and differentiating HSC derived from donors of all examined ages. The expression level experiments showed that αSRA was gradually up‐regulated during HSC differentiation, but no significant differences were observed between newborn, young, and elderly HSC cultures. Our data demonstrated that HSC, isolated from subjects of different ages, re‐expressed αSMA, but its levels and expression pattern varied considerably in the newborn with respect to the young adult and elderly donors. These results are discussed in relation to the myogenic differentiation capability of HSC during human muscle senescence.
The Prx Q protein of Arabidopsis thaliana is a member of the luminal chloroplast proteome
Authors: Petersson Ulrika A. , Kieselbach Thomas , García-Cerdán José G. , Schröder Wolfgang P.
Published: October 2006

Peroxiredoxins have been discovered in many organisms ranging from eubacteria to mammals, and their known biological functions include both oxidant defense and signal transduction. The genome of Arabidopsis thaliana encodes for ten individual peroxiredoxins, of which four are located in the chloroplast. The best‐characterized member of the chloroplast peroxiredoxins is 2‐Cys Prx that is associated with the stroma side of the thylakoid membrane and is considered to participate in antioxidant defense and protection of photosynthesis. This study addressed the chloroplast peroxiredoxin Prx Q and showed that its subcellular location is the lumen of the thylakoid membrane. To get insight in the biological function of the Prx Q protein of Arabidopsis, the protein levels of the Prx Q protein in thylakoid membranes were studied under different light conditions and oxidative stress. A T‐DNA knockout mutant of Prx Q did not show any visible phenotype and had normal photosynthetic performance with a slightly increased oxygen evolving activity.
The Polycomb‐associated protein Rybp is a ubiquitin binding protein
Authors: Arrigoni Rachele , Alam Steven L. , Wamstad Joseph A. , Bardwell Vivian J. , Sundquist Wesley I. , Schreiber-Agus Nicole
Published: October 2006

The Rybp protein has been promoted as a Polycomb group (PcG)‐associated protein, but its molecular function has remained elusive. Here we show that Rybp is a novel ubiquitin binding protein and is itself ubiquitinated. The Rybp interacting PcG protein Ring1B, a known ubiquitin E3 ligase, promotes Rybp ubiquitination. Moreover, one target of Rybp's ubiquitin binding domain appears to be ubiquitinated histone H2A; this histone is a substrate for Ring1B's E3 ligase activity in association with gene silencing processes. These findings on Rybp provide a further link between the ubiquitination system and PcG transcriptional repressors.
Notes on the chemistry of Maronea constans and Maronea polyphaea (Fuscideaceae)
Authors: LaGreca Scott
Published: October 2006

The crustose lichen genus Maronea A. Massal (Fuscideaceae) comprises about 12 species worldwide (Kantvilas 2001, 2004). The easily recognized, diagnostic features of this group of lichens are the lecanorine apothecia, Teloschistes-type ascus, and numerous spores per ascus, and these have contributed to a very stable generic concept over the years. As in many genera of lichenized fungi, however, differing species concepts have led to confusion over how many taxa are recognized. Many species, and varieties and forms of Maronea that were described on the basis of minor morphological features have since been synonymized (e.g. Harris 2006; Magnusson 1934).
Absorption of ultra-short laser pulses and particle transport in dense targets
Authors: SHERLOCK M. , BELL A. R. , ROZMUS W.
Published: October 2006

A new version of the numerical code KALOS has been developed to solve the Vlasov-Fokker-Planck equation for electrons as well as EM wave propagation. KALOS represents the electron distribution function in momentum space by an expansion in spherical harmonics. Its unique features make possible simultaneous investigations of fast electron generation and transport and the collisional evolution of thermal particles, including the return current of cold electrons. We report here on results obtained in one spatial dimension. Absorption of 100fs, 1015W/cm2laser pulses has been studied at normal incidence in sharp-edged dense plasmas. We have studied the effect on absorption of energy transport into the target as well as the deviation of the electron distribution function from Maxwellian. It is shown that it is necessary to take into account collisional heat transport into the target in order to correctly model the absorption rate at the front surface.
Experience of micro-heterogeneous target fabrication to study energy transport in plasma near critical density
Authors: KHALENKOV A.M. , BORISENKO N.G. , KONDRASHOV V.N. , MERKULIEV Yu.A. , LIMPOUCH J. , PIMENOV V.G.
Published: October 2006

The experience of target fabrication with low-density and cluster heterogeneity is presented. Cluster plasma research is strongly dependent on target fabrication development and target structure characterization. Ten more target parameters should be measured for experiment interpreting in case of micro-heterogeneous plasma. Foam and foil targets, high-Z doped also, are produced and irradiated on the existing laser facilities. The density of 4.5 mg/cc cellulose triacetate in the form of regular three-dimensional polymer networks are achieved which is as low as plasma critical density for the third harmonic of iodine laser light. The possibilities of varying important target parameters, methods of their monitoring are discussed. Experiments with underdense foam targets with or without clusters irradiated on Prague Asterix Laser System (PALS) laser facility are analyzed preliminary for target optimization. Under-critical foams of varying structure (closed-cell foam or three-dimensional networks) and densities are reported for plasma experiments. Thermal and radiation transport in such targets are considered.
The Power of Double Vision: Tradition and Social Intervention in African Puppet Performance
Authors: Kruger Marie
Published: October 2006

The appeal of the puppet lies partly in its dual nature: it is at once a representative object without life while at the same time it enacts the imagined life with which it is endowed by the puppeteer. Marie Kruger argues that this duality makes puppetry a uniquely effective way of questioning the very traditional values it appears to embody, and so of stimulating a sense of the need for social change. She relates her argument to the long tradition of puppetry among the Bamana people of Mali, and specifically to the performance of the Bin Sogo bo, an animal masquerade in which the ‘characters’ adumbrate human qualities with effective ambiguity. Marie Kruger is Chair of the Department of Drama at the University of Stellenbosch, South Africa, where puppetry is offered as a performance option. She is the author of Puppetry: a Guide for Beginners and has also published in the South Africa Theatre Journal. Over the past twenty years she has directed numerous puppet productions for all ages, and is currently leading a research project to document the nature and application of African puppet traditions.
Martin Crimp in conversation with Aleks Sierz The Question Is the Ultimate in Discomfort
Authors: Crimp Martin
Published: October 2006

Martin Crimp is one of the most exciting British playwrights to have emerged since the 1980s: his work is characterized by its vision of contemporary society as a place of social decay, moral compromise, and barely suppressed violence. He is also a writer whose work engages with both British and European theatre traditions. He started his career in 1981 at the Orange Tree Theatre, a fringe venue in Richmond, and this theatre produced all his early work, including Dealing with Clair and Play with Repeats. But it was when he became a Royal Court playwright in 1990, with No One Sees the Video, that he achieved international success and recognition. Three plays in particular – The Treatment, Attempts on Her Life and The Country – have become recognized masterpieces. Crimp has also pursued a parallel career as a translator and adapter of classics such as Molière's The Misanthrope and Sophocles' The Women of Trachis (as Cruel and Tender). The interview with Aleks Sierz which follows is assembled from conversations with Martin Crimp in London during February and March 2006, and the NTQ Checklist of Crimp's work on page 361 is derived from materials assembled by Sierz for his forthcoming book from Methuen, The Theatre of Martin Crimp.
Towards self-predicting systems: What if you could ask ‘what-if’?
Authors: THERESKA ENO , NARAYANAN DUSHYANTH , GANGER GREGORY R.
Published: October 2006

Today, management and tuning questions are approached using if… then… rules of thumb. This reactive approach requires expertise regarding system behavior, making it difficult to deal with unforeseen uses of a system’s resources and leading to system unpredictability and large system management overheads. We propose a What…if… approach that allows interactive exploration of the effects of system changes, thus converting complex tuning problem into simpler search problems. Through two concrete management problems, automating system upgrades and deciding on service migrations, we identify system design changes that enable a system to answer What…if… questions about itself.
The phenomenon of object omission in child L2 French
Authors: PRÉVOST PHILIPPE
Published: October 2006

This paper investigates object omission in French longitudinal production from two English-speaking children (Lightbown, 1977). Similar patterns of object omission are observed: direct objects start being dropped as transitive verbs are emerging and licit and illicit null objects occur in all recordings thereafter. Moreover, the incidence of illicit null objects drops at about the same time in both children (month 20), which corresponds to the moment object clitics start being used productively and to the end of the root infinitive period (Prévost, 1997). I argue that object omission is an instance of clitic-drop and is related to processing difficulties. In particular, both the projection of full-fledged representations and the production of object clitics (which occupy non-canonical object positions in French) increase computational complexity for children. Object-drop in child L2 French does not seem to be affected by L1 transfer nor to be related to significant difficulties with properties at the syntax/pragmatics interface.