bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge transport mechanism in intercalated polypyrrole aluminum‐pillared montmorillonite clay nanocomposites
Authors: Shakoor Abdul , Rizvi Tasneem Zahra , Hina Maryam
Published: November 2011

Nanocomposites based on intercalated conducting polypyrrole (PPy) into the galleries of inorganic aluminum‐pillared Montmorillonite (Al‐PMMT) clay with varying concentrations of Al‐PMMT were prepared by in situ chemical polymerization. The intercalation was confirmed by X‐ray diffraction pattern. Charge transport mechanism in these composites was investigated by temperature dependent direct current conductivity measurements. An increase in DC conductivity value on addition of (Al‐PMMT) clay in the composites at all temperatures and a transition from three‐dimensional (3D) Mott's variable range hopping (VRH) process in pristine PPy to one‐dimensional (1D) Mott's VRH process in the intercalated polymer composites has been observed. This transition in charge transport mechanism of PPy from 3D VRH to 1D VRH on intercalation has been interpreted in terms of straightening and linearization of polymer chains and decrease in inter‐chain interactions in the intercalated PPy. Enhancement in mechanical properties and increase in thermal stability of the nanocomposites was also observed with the increase in weight percentage of Al‐PMMT in PPy‐Al‐PMMT composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Optimization of the chain transfer agent incremental addition in SBR emulsion polymerization
Authors: Delfa Gerardo Martínez , Boschetti Carlos E.
Published: November 2011

The incremental addition of chain transfer agent (CTA) in an emulsion styrene‐butadiene polymerization reaction was optimized, using a chemometric approach that involves (a) an experimental design, in which the amount of CTA in each addition were the factors; (b) an artificial neural network modeling to obtain responses for each required processability property (i.e., Mooney viscosity and number‐ and weight‐average molecular weight); and (c) a simultaneous desirability response, due to several properties had to be optimized at a time. As a result, an 8% increase in productivity was accomplished, and some relationships were derived among CTA additions and polymer evolution, Mooney viscosity and molecular weights. The study was carried out to further apply this strategy in the production plant. The challenge was to keep the quality of the produced polymer, particularly in terms of processability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
NIR‐laser based detection of the photopolymerization state of acrylate coatings suitable for in situ measurements
Authors: Bach M. , Heering W.
Published: November 2011

The present article describes a method for the determination of the radical photopolymerization conversion of acrylic coatings suitable for an in situ monitoring during the coating process. Acrylate based coatings are increasingly used in many kinds of industrial coating processes, because of advantages of the solvent‐free application process. The applied method is based on 1620 nm light absorption of the acrylate. To overcome the disadvantages of a common NIR spectrometer, only the diffuse reflection of the relevant discrete wavelength at 1620 nm and of a reference wavelength is measured. A sophisticated sensor setup including an optical spatial filter and lock‐in amplified signal processing is used to achieve a sufficient signal to noise ratio. The capability of the sensor to discriminate between polymerized and unpolymerized coatings on metal substrates down to a coating thickness of 16 μm is demonstrated. Furthermore, the information on polymerization from larger depth in TiO2 pigmented coatings is investigated. The results can be analytically modeled in analogy to the Lambert–Beer's law, resulting in a detection limit of a maximum pigment concentration of 15 wt % with 100 μm coating thickness. The presented sensor design is suitable to be used in an industrial production environment for example in screen printing applications as a monitoring and quality control tool. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rhodium(I) complex catalyst immobilized on terpolymers of N‐vinylpyrrolidinone and 1‐vinylimidazole
Authors: Strzelec Krzysztof , Wąsikowska Karolina , Cypryk Marek , Pospiech Piotr
Published: November 2011

The hydrosilylation of cyclohexanone and acetone with triethysilane and diphenysilane catalyzed by polymer‐supported Rh(I) complex has been investigated. Two terpolymers of styrene, divinylbenzene, and 1‐vinylimidazole (S/DVB/VI) or N‐vinylpyrrolidinone (S/DVB/NVP) were used as the catalysts supports. Physical characterization of these materials has involved the measurements of the structural parameters in the dry and swollen states by DSC, the nitrogen BET adsorption method and inverse steric exclusion chromatography ISEC. From these results it can be concluded that the original polymer structure has been changed during the complex attachment giving rise to materials of higher porosity. X‐ray photoelectron spectroscopy XPS, IR, and AAS spectroscopy were used to characterization of heterogeneous complexes before and after use. The effect of the morphology of the support on the catalytic properties of the polymer‐supported Rh(I) species was tested in the hydrosilylation of ketones and correlated with the reaction mechanism. It was demonstrated that the high selectivity of homogeneous rhodium complex toward the silyl ethers can be partially reversed to the dehydrogenative silylation products by a proper choice of polymer support with favorable microporous structure. Recycling tests demonstrated high stability of the supported catalysts during prolonged use. The constant selectivity of the supported catalysts demonstrated during recycling experiments showed that they could be useful for practical application. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Production and characterization of poly(vinyl alcohol)/poly(vinylpyrrolidone) iodine/poly(ethylene glycol) electrospun fibers with (hydroxypropyl)methyl cellulose and aloe vera as promising material for wound dressing
Authors: Uslu İbrahim , Aytimur Arda
Published: November 2011

Biocompatible poly(vinyl alcohol)/poly (vinylpyrrolidone) iodine/poly(ethylene glycol) fibers containing (hydroxypropyl)methyl cellulose (HPMC) and aloe vera were successfully prepared by electrospinning their aqueous solution. Aloe vera which is known to be effective in the treatment of various wounds was added to the polymer solution. HPMC was added to the system as the water retention agent. The hybrid fiber mats were subjected to detailed analysis using a differential scanning calorimeter, a scanning electron microscope (SEM), and a Fourier transform infrared spectrometer. Images obtained from the SEM showed that the polymer fibers were linear, homogenous, and contained no beading. The fiber diameters ranged between 100 and 900 nm. It was seen that the electrospun mats obtained could potentially be used as a material for dressing wounds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Secretion and formation of perimicrovillar membrane in the digestive system of the Sunn pest, Eurygaster integriceps (Hemiptera: Scutelleridae) in response to feeding
Authors: Mehrabadi Mohammad , Bandani Ali Reza
Published: November 2011

In this study, development of perimicrovillar membrane (PMM) from midgut cells of starved and fed Eurygaster integriceps (Hemiptera: Scutelleridae) was studied. Three different approaches, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), marker enzymes of the PMMs (α‐glucosidase), perimicrovillar space (aminopeptidase), and microvillar membranes (β‐glucosidase) were used. Activities of these enzymes were remarkably low in the starved insects. Moreover, microscopic observations revealed that PMM is not present in the starved insect. Activities of enzymatic markers increased at 5 h postfeeding, and TEM and SEM observations showed the formation of PMM as well as migration of double‐membrane vesicles from center of the columnar cell to the cell apex. The highest PMM was observed at 20 h postfeeding which at this time marker enzyme activity, such as α‐glucosidase activity, was high, too. Thus, at 20 h postfeeding, PMM system was evident and epithelial cells were completely covered by PMM system. After 20 h postfeeding, presence of the fine holes in PMM started to be seen and at 40 h post‐feeding, observation showed degradation of PMM system. Thus, it could be concluded that PMM in E. integriceps is secreted by epithelial cell membrane when needed and its secretion and formation is regulated by feeding. This system was not present in the starved insects as its development takes place at 5 h postfeeding. © 2011 Wiley Periodicals, Inc.
A Simplified Optimization Strategy for Nonlinear Tuned Mass Damper in Structural Vibration Control
Authors: Guo Wei , Li Hong‐Nan , Liu Guo‐Huan , Yu Zhi‐Wu
Published: November 2011

In this paper, a simplified optimization strategy for the nonlinear tuned mass damper (TMD) is presented, and the optimal parameter setting can be simply determined, by which the nonlinear TMD is effective over a wide frequency range. In the given numerical model, the nonlinear TMD is attached to the structure, which is represented by a single‐degree‐of‐freedom system, and the environmental load is assumed to be the Gaussian white noise process. Governing differential equations of motion of the coupled structure‐TMD system are derived, and the equivalent linearization method is introduced in the numerical calculation. The standard deviation of the structural displacement is adopted as the optimized objective function. Furthermore, it is pointed out that the response of the system can be controlled in a case of multiple probable steady‐state processes caused by the nonlinearity of the stiffness element. Different from the linear TMD, the performance of the nonlinear TMD may be influenced by the excitation. Thus, the performance sensitivity of optimal nonlinear TMD is investigated with different excitation intensities and structural damping ratios. The results show that the sensitivity may limit the engineering applications of nonlinear TMD.
Use of Hospital Episode Statistics to investigate abdominal aortic aneurysm surgery
Authors: Johal A , Mitchell D , Lees T , Cromwell D , van der Meulen J
Published: November 2011

Background

A coding framework was evaluated to study patients undergoing open surgical replacement of an abdominal aortic aneurysm (AAA) in the English Hospital Episode Statistics (HES) database. The objective was to create groups of patients who are homogeneous with respect to diagnosis, prognosis and treatment.

Methods

The frequency and consistency of potentially relevant diagnosis (International Classification of Diseases, 10th revision) and procedure (Office of Population Censuses and Surveys Classification, 4th revision) codes were assessed in patients admitted to English National Health Service hospitals between April 2003 and March 2008. Administrative codes were compared with diagnosis and procedure codes to check that patients who had undergone emergency surgery for a ruptured AAA were admitted as an emergency.

Results

Of 20 290 patients undergoing AAA replacement, 19 250 (94·9 per cent) had a consistent diagnosis (unruptured or ruptured AAA); 79·3 per cent of patients with an emergency replacement were coded as having a ruptured AAA and 95·7 per cent of those with a non-emergency replacement as having an unruptured AAA. Of patients who had undergone emergency replacement of a ruptured AAA, 93·3 per cent were coded as having been admitted as an emergency.

Conclusion

Coding consistency was high. The proposed framework could define homogeneous groups by combining diagnosis, procedure and administrative codes. It also allows an assessment of potential miscoding at national and hospital level. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
A validated LC‐MS/MS method for the determination of vinflunine in plasma and its application to pharmacokinetic studies
Authors: Pin Huang , Hong‐min Lu , Ming Ye , Qin Li
Published: November 2011

A rapid, simple and sensitive LC‐MS/MS method for the quantification of vinflunine in plasma was developed and validated. The analysis involved a simple liquid–liquid extraction. After making alkaline with NaOH, plasma was extracted with methyl tert‐butyl ether and the organic extract was then evaporated and the residue was reconstituted in mobile phase. The reconstituted solution was injected into an HPLC system and was subjected to reverse‐phase HPLC on a 5 µm ODS‐3 column at a flow‐rate of 0.2 mL/min. The mobile phase consisted of ammonium acetate (0.02 mol/L, pH = 3.0) and acetonitrile (20:80). Vinflunine was detected in the single ion monitoring mode using target ions at m/z 817.4/160.1/142.3 for vinflunine and m/z 447.2/128.3/112.1 for gefitinib (internal standard). Standard curves were linear over the concentration range of 5–1000 ng/mL. The mean predicted concentrations of the quality control samples deviated by less than 2% from the corresponding nominal values; the intra‐assay and inter‐assay precisions of the assay were within 7% relative standard deviation. The extraction recovery of vinflunine was more than 80%. The validated assay was applied to a pharmacokinetic study of vinflunine in plasma following the administration of a single vinflunine injection (2 mg/kg). Copyright © 2011 John Wiley & Sons, Ltd.
Simultaneous quantification of centchroman and its 7‐demethylated metabolite in rat dried blood spot samples using LC‐MS/MS
Authors: Lal Jawahar , Sharma Nidhi
Published: November 2011

An approach has been developed for the quantitative determination of concentrations of centchroman (I), a nonsteroidal once‐a‐week oral contraceptive, and its major metabolite (7‐desmethyl centchroman, II) using dried blood spots (DBS) on paper, rather than conventional plasma samples. The assay employed simple solvent extraction of the DBS sample circle (6 mm) requiring small blood volumes (30 μL) followed by reversed‐phase HPLC separation, combined with multiple reaction monitoring mass spectrometric detection. The calibration plot in matrix using d‐trans‐hydroxy chroman as internal standard (IS) was linear (r2 = 0.998) over ranges of 1.5–240 and 4.5–720 ng/mL for I and II, respectively. The recoveries of both I and II were always >60% with quantification limits (signal‐to‐noise ratio = 10) of 1.5 and 4.5 ng/mL for I and II, respectively. The intra‐day and inter‐day precision (%RSD) and accuracy (%bias) variations in blood spots for both I and II were better than 13%. Moreover, both I and II were stable in DBS for at least 3 months when stored at room temperature. The developed method was successfully applied to the pharmacokinetic interaction study after oral administration of centchroman with and without co‐administration of carbamazepine in female Sprague–Dawley rats using serial sampling and results were comparable with the plasma concentrations reported earlier. Copyright © 2011 John Wiley & Sons, Ltd.
Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions
Authors: Saleh Sayed M. , Ali Reham , Wolfbeis Otto S.
Published: November 2011

We report that the luminescence of upconverting luminescent nanoparticles (UCLNPs) is quenched by heavy metal ions and halide ions in aqueous solution. The UCLNPs consist of hexagonal NaYF4 nanocrystals doped with trivalent rare earth ions and were synthesized by both the oleic acid (solvothermal) method and the ethylenediaminetetraacetic acid (co‐precipitation) method. Quenching was studied for the CuII, HgII, PbII, CdII, CoII, AgI, FeIII, ZnII, bromide, and iodide ions and is found to be particularly strong for HgII. Stern–Volmer plots are virtually linear up to quencher concentrations of 10–25 mM, but deviate from linearity at higher quencher concentrations, because static quenching causes an additional effect. The UCLNPs display two main emission bands (blue, green, red or near‐infrared), and the quenching efficiencies for these are found to be different. The effect seems to be generally associated with UCLNPs because it was observed for all UCLNPs doped with trivalent lanthanide ions including YbIII, ErIII, HoIII, and TmIII. The results are discussed in terms of quenching mechanisms and with respect to potential applications such as optical sensing.
Activating Water: Important Effects of Non‐leaving Groups on the Hydrolysis of Phosphate Triesters
Authors: Kirby Anthony J. , Medeiros Michelle , Oliveira Pedro S. M. , Orth Elisa S. , Brandão Tiago A. S. , Wanderlind Eduardo H. , Amer Almahdi , Williams Nicholas H. , Nome Faruk
Published: November 2011

The high rate of spontaneous hydrolysis of tris‐2‐pyridyl phosphate (TPP) is explained by the activating effects of the non‐leaving (“spectator”) groups on POAr cleavage, and not by intramolecular catalysis. Previous work on phosphate‐transfer reactions has concentrated on the contributions to reactivity of the nucleophile and the leaving group, but our results make clear that the effects of the non‐leaving groups on phosphorus can be equally significant. Rate measurements for three series of phosphate triesters showed that sensitivities to the non‐leaving groups are substantial for spontaneous hydrolysis reactions, although significantly smaller for reactions with good nucleophiles. There are clear differences between triaryl and dialkyl aryl triesters in sensitivities to leaving and non‐leaving groups with the more reactive triaryl systems showing lower values for both βLG and βNLG. Intramolecular catalysis of the hydrolysis of TPP by the neighbouring pyridine nitrogens is insignificant, primarily because of their low basicity.
Highly Regioselective Hydroaminomethylation of Terminal Olefins to Linear Amines Using Rh Complexes with a Tetrabi Phosphorus Ligand
Authors: Liu Guodu , Huang Kexuan , Cai Chaoxian , Cao Bonan , Chang Mingxin , Wu Wenjun , Zhang Xumu
Published: November 2011

A highly regioselective hydroaminomethylation of terminal olefins catalyzed by Rh complexes with 2, 2′, 6, 6′‐tetrakis ((diphenylphosphino)methyl)‐1, 1′‐biphenyl (Tetrabi) ligand has been developed. Up to 99 % amine selectivity, 168 linear/branched amine product ratio (n/i), and 97.4 % linear amine yield has been obtained at a substrate/rhodium precursor ratio (S/Rh) of 1000 with this methodology. The turnover number was achieved 6930 at 10000 S/Rh ratio, and the n/i can reach up to >525. Several different olefins and secondary amines have been applied successfully with high chemoselectivity (99 %), yield (>98 %), and regioselectivity (>120).
Resistance of wood pellets to low airflow
Authors: Yazdanpanah F. , Lau A. , Sokhansanj S. , Lim C. J. , Bi X. , Melin S.
Published: November 2011

The pressure drop versus low airflow from 0.000117 to 0.1 m/s was measured across a fixed bed of wood pellets. Wood pellets were on average 6.2 mm in diameter and 12 mm in length. The moisture content of wood pellets ranged from 2.8% to 8.1%. Four equations, Darcy, Shedd, Hukill and Ergun representing flow versus static pressure drop for bulk granules were fitted to the experimental data. At airflows below 0.01 m/s, the predicted pressure drops using all four equations deviated from experimental data. This deviation was the largest for the Darcy equation and the smallest for Ergun equation. © 2011 Canadian Society for Chemical Engineering
Power and Perceived Expressed Emotion of Voices: Their Impact on Depression and Suicidal Thinking in Those Who Hear Voices
Authors: Connor Charlotte , Birchwood Max
Published: November 2011

Considerable focus has been given to the interpersonal nature of the voice‐hearing relationship and how appraisals about voices may be linked with distress and depression (the ‘cognitive model’). Research hitherto has focused on appraisals of voice power, but the supportive and affiliative quality of voices, which may act to mitigate distress, is not understood. We explored appraisals of voices' power and emotional support to determine their significance in predicting depression and suicidal thought. We adapted the concept of expressed emotion (EE) and applied it to measure voice hearers' perception of the relationship with their voice(s). In a sample of 74 voice hearers, 55.4% were moderately depressed. Seventy‐eight who rated their voices as high in both power and EE had a large and significant elevation in depression, suggesting that co‐occurrence of these appraisals impacts on depression. Analysis of the relationship between power and EE revealed that many voices perceived as low in power were, nevertheless, perceived as high in EE. Those rating their voices as emotionally supportive showed the lowest levels of depression and suicidal thinking. These findings highlight the protective role that the supportive dimension of the voice/voice‐hearer relationship may have. Copyright © 2011 John Wiley & Sons, Ltd.

Key Practitioner Message

Appraisals of social rank and EE impact on the depressive and suicidal status of voice‐hearers.

The emotionally supportive dimension of the voice‐hearing relationship may have a protective role in the affective response of voice hearers.

Therapeutic interventions should consider the emotionally supportive needs of voice‐hearers,
Co‐simulation‐based modeling and performance analysis of hybrid fiber–wireless links
Authors: Chettat H. , Simohamed L. M. , Algani C. , Polleux J.‐L. , Billabert A.‐L. , Yalaoui A.
Published: November 2011

We present a new approach for the performance analysis of hybrid fiber/wireless communication systems. This approach is based on a co‐simulation using two types of dedicated software: the first is used for RF/wireless systems whereas the second is devoted to optical communication systems. The proposed method enables simultaneous simulation of all elements of the radio‐over‐fiber link with accurate modeling. A low‐cost wireless local area network over a fiber distribution system is implemented in order to validate the results experimentally. Simulation results are in good agreement with experimental measurements in terms of EVM evolution for different link element configurations. Copyright © 2011 John Wiley & Sons, Ltd.
Bandwidth borrowing‐based QoS approach for adaptive call admission control in multiclass traffic wireless cellular networks
Authors: Khanjari Sharifa Al , Arafeh Bassel , Day Khaled , Alzeidi Nasser
Published: November 2011

This paper proposes a QoS approach for an adaptive call admission control (CAC) scheme for multiclass service wireless cellular networks. The QoS of the proposed CAC scheme is achieved through call bandwidth borrowing and call preemption techniques according to the priorities of the traffic classes, using complete sharing of the available bandwidth. The CAC scheme maintains QoS in each class to avoid performance deterioration through mechanisms for call bandwidth degradation, and call bandwidth upgrading based on min–max and max–min policies for fair resource deallocation and reallocation, respectively. The proposed adaptive CAC scheme utilizes a measurement‐based online monitoring approach of the system performance, and a prediction model to determine the amount of bandwidth to be borrowed from calls, or the amount of bandwidth to be returned to calls. The simulation‐based performance evaluation of the proposed adaptive CAC scheme shows the strength and effectiveness of our proposed scheme. Copyright © 2011 John Wiley & Sons, Ltd.
Intralake training set of fossil Cladocera for paleohydrological inferences: evidence for multicentennial drought during the Medieval Climate Anomaly
Authors: Nevalainen Liisa , Luoto Tomi P.
Published: November 2011

We investigated an intralake surface sediment data set for fossil Cladocera from Lake Pieni‐Kauro, eastern Finland, with an objective to develop a paleohydrological inference model for lake level reconstructions. The Cladocera assemblages showed high heterogeneity among the sampling sites according to the water depth gradient, thus enabling the construction of a quantitative inference model for water level reconstructions. The strongest model was developed using weighted averaging with classical deshrinking regression. This model had a jackknifed coefficient of determination of 0.79 and a root mean squared error of prediction of 0.79 m. We tested the performance of the model on previously available Cladocera stratigraphy and Cladocera‐based and chironomid‐based lake level reconstructions from Lake Iso Lehmälampi, southern Finland. The lake level reconstructions, based on different proxies and independent inference models, showed high levels of similarity, indicating a period of lower water table during the Medieval Climate Anomaly around 1000  ad. The results suggest that the applicability of intralake paleohydrological models may not be regionally restricted when applied to similar lake types and, therefore, provide an alternative perspective on paleolimnological training set design and paleoclimatological inferences. Copyright © 2011 John Wiley & Sons, Ltd.
Activation of the NLRP3 inflammasome by Mycobacterium tuberculosis is uncoupled from susceptibility to active tuberculosis
Authors: Dorhoi Anca , Nouailles Geraldine , Jörg Sabine , Hagens Kristine , Heinemann Ellen , Pradl Lydia , Oberbeck‐Müller Dagmar , Duque‐Correa Maria Adelaida , Reece Stephen T. , Ruland Jürgen , Brosch Roland , Tschopp Jürg , Gross Olaf , Kaufmann Stefan H. E.
Published: November 2011

As a hallmark of tuberculosis (TB), Mycobacterium tuberculosis (MTB) induces granulomatous lung lesions and systemic inflammatory responses during active disease. Molecular regulation of inflammation is associated with inflammasome assembly. We determined the extent to which MTB triggers inflammasome activation and how this impacts on the severity of TB in a mouse model. MTB stimulated release of mature IL‐1β in macrophages while attenuated M. bovis BCG failed to do so. Tubercle bacilli specifically activated the NLRP3 inflammasome and this propensity was strictly controlled by the virulence‐associated RD1 locus of MTB. However, Nlrp3‐deficient mice controlled pulmonary TB, a feature correlated with NLRP3‐independent production of IL‐1β in infected lungs. Our studies demonstrate that MTB activates the NLRP3 inflammasome in macrophages in an ESX‐1‐dependent manner. However, during TB, MTB promotes NLRP3‐ and caspase‐1‐independent IL‐1β release in myeloid cells recruited to lung parenchyma and thus overcomes NLRP3 deficiency in vivo in experimental models.
Developmental regulation of Th17‐cell capacity in human neonates
Authors: Black Allison , Bhaumik Suniti , Kirkman Richard L. , Weaver Casey T. , Randolph David A.
Published: November 2011

Human neonates are at significantly greater risk of serious infection than immunocompetent adults. In particular, very low birth weight infants in the neonatal intensive care nursery are at high risk of developing life‐threatening bacterial and fungal infections. Recent studies have identified Th17 cells as critical mediators of immunity to bacterial and fungal infections at epithelial barriers. Little is known, however, about the ontogeny of Th17‐cell responses in humans. The frequency of serious bacterial infections in preterm infants and the importance of Th17 cells in providing protection against such infections in animal studies prompted us to study Th17‐cell development in human neonates. Naïve CD4+ T cells from extremely preterm infants, term infants, and adults were assayed for their capacity to develop into Th17 effector cells. Surprisingly, Th17‐cell capacity was inversely related to developmental age. Neonates expressed higher levels of IL‐23R, RORγt, and STAT3 prior to activation and showed a significant Th17‐cell bias after activation. In contrast, adult cells expressed more TBX21 with a corresponding Th1‐cell bias. CD161 expression on Th17‐cell precursors was also developmentally regulated. Our results suggest there is significant developmental regulation of CD4+ effector lineages with a strong bias toward Th17‐cell development early in life.
Anti IL‐17A therapy inhibits bone loss in TNF‐α‐mediated murine arthritis by modulation of the T‐cell balance
Authors: Zwerina Karin , Koenders Marije , Hueber Axel , Marijnissen Renoud J. , Baum Wolfgang , Heiland Gisela Ruiz , Zaiss Mario , Mclnnes Iain , Joosten Leo , van den Berg Wim , Zwerina Jochen , Schett Georg
Published: November 2011

Tumour necrosis factor alpha (TNF‐α) is a major inducer for inflammation and bone loss. Here, we investigated whether interleukin (IL)‐17 plays a role in TNF‐α‐mediated inflammation and bone resorption. Human TNF‐α transgenic (hTNFtg) mice were treated with a neutralizing anti‐IL‐17A antibody and assessed for inflammation, cartilage and bone damage. T‐cell transcription factors and lymphokine patterns were measured in the LNs. IL‐17A inhibition in the absence of IL‐1 was also evaluated by treating hTNFtg/IL‐1−/− mice with an IL‐17A neutralizing antibody. IL‐17A neutralization had only minor effects on TNF‐α‐induced inflammation but effectively reduced local and systemic bone loss by blocking osteoclast differentiation in vivo. Effects were based on a shift to bone‐protective T‐cell responses such as enhanced Th2 differentiation, IL‐4 and IL‐12 expression and Treg cell numbers. Whereas inflammation in hTNFtg/IL‐1−/− mice was highly sensitive to IL‐17A blockade, no shift in the T‐cell lineages and no additional benefit on bone mass were observed in response to IL‐17A neutralization. We thus conclude that IL‐17A is a key mediator of TNF‐α‐induced bone loss by closely interacting with IL‐1 in blocking bone protective T‐cell responses.
Type‐I IFN drives the differentiation of short‐lived effector CD8+ T cells in vivo
Authors: Wiesel Melanie , Crouse Josh , Bedenikovic Gregor , Sutherland Andrew , Joller Nicole , Oxenius Annette
Published: November 2011

Two subsets of CD8+ T cells are generated early during an immune response; one of these subsets forms the memory pool, known as memory precursor effector cells (MPECs), identified by high expression of CD127 and low expression of KLRG1, whereas the other subset forms short‐lived effector cells (SLECs) identified by low expression of CD127 and high expression of KLRG1. Here, we studied in vivo the role of type‐I IFN in this fate decision. We found that under priming conditions dominated by type‐I IFN, as observed in lymphocytic choriomeningitis virus (LCMV) infection, type‐I IFN signaling directly impacted the regulation of T‐bet and thus the early fate decision of CD8+ T cells. In the absence of type‐I IFN signaling, CD8+ T cells failed to form SLECs but could form MPECs that give rise to functional memory CD8+ T cells. Together, these findings identify type‐I IFN as an important factor driving SLEC differentiation and thus instructing the early division between the effector and memory precursor CD8+ T‐cell pool.
Ba6P12N17O9Br3 – A Column‐Type Phosphate Structure Solved from Single‐Nanocrystal Data Obtained by Automated Electron Diffraction Tomography
Authors: Mugnaioli Enrico , Sedlmaier Stefan J. , Oeckler Oliver , Kolb Ute , Schnick Wolfgang
Published: November 2011

Oxonitridophosphate Ba6P12N17O9Br3 was synthesized by heating a multicomponent mixture of BaBr2, BaS, phosphoryl triamide and thiophosphoryl triamide in an evacuated and sealed silica‐glass ampoule to 750 °C. Ba6P12N17O9Br3 was obtained as the main product as a nanocrystalline powder. The crystal structure was determined ab initio on the basis of electron diffraction data acquired from a single needle‐shaped nanocrystal by automated diffraction tomography. Ba6P12N17O9Br3 crystallizes in the hexagonal space group P63/m (no. 176) with unit cell parameters a = 14.654(19), c = 8.255(9) Å and Z = 2. Its structure includes triangular, column‐shaped anions of ∞1{(P12N17O9)9–}, which are built from vertex‐sharing P(O,N)4 tetrahedra with 3‐rings and three‐coordinate nitrogen atoms. The 1D anions are separated by Ba2+ and Br– ions, which are arranged in channels parallel to the phosphate anions along [001]. The Ba2+ ions are eight‐ and nine‐coordinated by Br– and O/N atoms, respectively.
Ruthenium‐Catalyzed Regioselective Cyclization of Aromatic Ketones with Alkynes: An Efficient Route to Indenols and Benzofulvenes
Authors: Chinnagolla Ravi Kiran , Jeganmohan Masilamani
Published: November 2011

The reactions of substituted acetophenones with diphenylacetylene in the presence of [{RuCl2(p‐cymene)}2] (2 mol‐%), AgSbF6 (8 mol‐%), and Cu(OAc)2·H2O (25 mol‐%) in 1,2‐dichloroethane at 120 °C for 10 h provided substituted indenol derivatives in good‐to‐excellent yields. Under similar reaction conditions, unsymmetrical alkynes such as 1‐phenyl‐1‐propyne, 1‐phenyl‐1‐butyne, 1‐phenyl‐2‐(trimethylsilyl)acetylene, and a substituted enyne also reacted efficiently with substituted acetophenones to afford the corresponding indenol derivatives in a highly regioselective manner. The amount of silver salt plays a key role in the reaction. When the amount of silver salt exceeded more than 8 mol‐% in the presence of 2 mol‐% [{RuCl2(p‐cymene)}2], a different type of dehydration product, namely a benzofulvene derivative, started to appear. In the presence of 20 mol‐% AgSbF6, substituted acetophenones readily reacted with alkynes in the presence of [{RuCl2(p‐cymene)}2] (2 mol‐%) to give benzofulvene derivatives in excellent yields. A plausible reaction mechanism is proposed to account for the cyclization reaction.
Convergent Preparation of DimLex Hexasaccharide Analogues (Eur. J. Org. Chem. 34/2011)
Authors: Hendel Jenifer L. , Auzanneau France‐Isabelle
Published: November 2011

The cover picture shows an artist's impression of colorectal cancer cells displaying the tumor‐associated carbohydrate antigen dimeric Lex (dimLex). This hexasaccharide can be targeted for the development of anticancer vaccines that will help the immune system to selectively distinguish cancerous cells (Foe) from noncancerous cells (Friend). An analogue of the dimLex hexasaccharide in which a galactosyl residue was replaced by a glucose unit was prepared. This analogue will be used in the preparation of such a vaccine candidate. This cover picture was designed and produced by Dr. Uwe Oehler, Department of Chemistry, University of Guelph, Ontario, Canada. Details of this work are described in the article by J. L. Hendel and F.‐I. Auzanneau on p. 6864 ff.
Rapid determination of protein binding constant by a pressure‐mediated affinity capillary electrophoresis method
Authors: Zhang Bo , Li You X. , Gao He N. , Bian Juan , Bao James J.
Published: November 2011

A new pressure‐mediated affinity capillary electrophoresis method for the rapid and accurate determination of drug–protein binding constants is described. A special combination of pressure and electrophoresis is used to shorten the electrophoresis and the overall analysis time to only a few minutes. At the same time, the suitability of this method is checked against a traditional fluorescence spectroscopy method. The binding constants of bovine serum albumin and a total of eight drugs with different pKa have been evaluated and compared with those determined by the fluorescence spectroscopy method and other methods in literature. The results indicate that the P‐ACE method is well suited for the determination of binding constants with weak interaction (Kb<105 M−1).
Categorical structured additive regression for assessing habitat suitability in the spatial distribution of mussel seed abundance
Authors: Pata M. P. , Kneib T. , Cadarso‐Suárez C. , Lustres‐Pérez V. , Fernández‐Pulpeiro E.
Published: November 2011

Categorical regression models enable the investigation of regression relationships between a polytomous response and a set of regressor variables. Depending on whether the categories are ordered or nominal, special categorical models such as cumulative and multinomial models have been proposed in the statistical literature. In this paper, we compare various categorical structured additive regression (STAR) models for assessing habitat suitability in the spatial distribution of mussel seed abundance in the Galician coast (northwest Spain). STAR models allow us to include nonlinear effects of continuous covariates on the basis of penalized splines whereas spatial effects can be represented via a Markov random field. Inference is based on a mixed model representation that allows for the simultaneous estimation of regression coefficients and smoothing parameters. Although cumulative models may seem to be the most natural choice in our application because of the ordinal nature of the response, multinomial models provide more detailed information on covariate effects as all effects are allowed to depend on the different categories of mussel seed abundance. The statistical procedures based on STAR models proved very useful in revealing valuable information towards the application of adequate management of this marine resource. Copyright © 2011 John Wiley & Sons, Ltd.
Modeling and Forecasting the Yield Curve by an Extended Nelson‐Siegel Class of Models: A Quantile Autoregression Approach
Authors: de Rezende Rafael B. , Ferreira Mauro S.
Published: November 2011

This paper compares the in‐sample fitting and the out‐of‐sample forecasting performances of four distinct Nelson–Siegel class models: Nelson–Siegel, Bliss, Svensson, and a five‐factor model we propose in order to enhance the fitting flexibility. The introduction of the fifth factor resulted in superior adjustment to the data. For the forecasting exercise the paper contrasts the performances of the term structure models in association with the following econometric methods: quantile autoregression evaluated at the median, VAR, AR, and a random walk. As a pattern, the quantile procedure delivered the best results for longer forecasting horizons. Copyright © 2011 John Wiley & Sons, Ltd.
Estimation and Forecasting of Locally Stationary Processes
Authors: Palma Wilfredo , Olea Ricardo , Ferreira Guillermo
Published: November 2011

This paper develops a state space framework for the statistical analysis of a class of locally stationary processes. The proposed Kalman filter approach provides a numerically efficient methodology for estimating and predicting locally stationary models and allows for the handling of missing values. It provides both exact and approximate maximum likelihood estimates. Furthermore, as suggested by the Monte Carlo simulations reported in this work, the performance of the proposed methodology is very good, even for relatively small sample sizes. Copyright © 2011 John Wiley & Sons, Ltd.
Emerging roles of p53 in glial cell function in health and disease
Authors: Jebelli Joseph D. , Hooper Claudie , Garden Gwenn A. , Pocock Jennifer M.
Published: November 2011

Emerging evidence suggests that p53, a tumor suppressor protein primarily involved in cancer biology, coordinates a wide range of novel functions in the CNS including the mediation of pathways underlying neurodegenerative disease pathogenesis. Moreover, an evolving concept in cell and molecular neuroscience is that glial cells are far more fundamental to disease progression than previously thought, which may occur via a noncell‐autonomous mechanism that is heavily dependent on p53 activities. As a crucial hub connecting many intracellular control pathways, including cell‐cycle control and apoptosis, p53 is ideally placed to coordinate the cellular response to a range of stresses. Although neurodegenerative diseases each display a distinct and diverse molecular pathology, apoptosis is a widespread hallmark feature and the multimodal capacity of the p53 system to orchestrate apoptosis and glial cell behavior highlights p53 as a potential unifying target for therapeutic intervention in neurodegeneration. © 2011 Wiley Periodicals, Inc.
Stab wound injury of the zebrafish telencephalon: A model for comparative analysis of reactive gliosis
Authors: Baumgart Emily Violette , Barbosa Joana S. , Bally‐cuif Laure , Götz Magdalena , Ninkovic Jovica
Published: November 2011

Reactive glia, including astroglia and oligodendrocyte progenitors (OPCs) are at the core of the reaction to injury in the mammalian brain with initially beneficial and later partially adverse functions such as scar formation. Given the different glial composition in the adult zebrafish brain with radial ependymoglia but no parenchymal astrocytes, we examined the glial response to an invasive stab wound injury model in the adult zebrafish telencephalon. Strikingly, already a few days after injury the wound was closed without any scar tissue. Similar to mammals, microglia cells reacted first and accumulated close to the injury site, while neither GFAP+ radial ependymoglia nor adult OPCs were recruited to the injury site. Moreover, OPCs failed to increase their proliferation after this injury, while the number of proliferating GFAP+ glia was increased until 7 days after injury. Importantly, neurogenesis was also increased after injury, generating additional neurons recruited to the parenchyma which survived for several months. Thus, these data suggest that the specific glial environment in the adult zebrafish telencephalon is not only permissive for long‐term neuronal survival, but avoids scar formation. Invasive injury in the adult zebrafish telencephalon may therefore provide a useful model to untangle the molecular mechanisms involved in these beneficial glial reactions. © 2011 Wiley Periodicals, Inc.
No association between bone mass and prolactin levels among patients with schizophrenia
Authors: Sugawara Norio , Yasui‐Furukori Norio , Fujii Akira , Saito Manabu , Sato Yasushi , Nakagami Taku , Tsuchimine Shoko , Kaneko Sunao
Published: November 2011

Objective

Decreased bone mineral density has been implicated in schizophrenic patients for long years. The purpose of this study was to assess the relationship between bone mass and prolactin levels in schizophrenic patients.

Methods

In this study, bone mass was measured using quantitative ultrasound densitometry of the calcaneus in 114 patients (49 males and 65 females). The osteosono‐assessment index (OSI) was calculated as a function of the speed of sound and transmission index. Estradiol, testosterone, and prolactin levels were also measured. Factors that influenced prolactin levels and bone mass were determined via multiple linear regression analysis.

Results

Among the female patients, body mass index and estradiol levels were independently and significantly associated with the OSI. Neither prolactin levels nor duration of antipsychotic treatment was associated with bone mass for either gender.

Conclusions

These findings suggest that prolactin levels do not contribute to poor bone mass, as assessed using the OSI among schizophrenic patients. However, the interpretation of our results was hampered by lack of data including differences in lifestyle and type of antipsychotic medications used in schizophrenic patients. Association between prolactin levels and low bone mineral density was not completely ruled out. Future research exploring prolactin levels and bone mineral density is warranted. Copyright © 2011 John Wiley & Sons, Ltd.
Electrospun polylactide/poly(ethylene glycol) hybrid fibrous scaffolds for tissue engineering
Authors: Wang Bei‐Yu , Fu Shao‐Zhi , Ni Pei‐Yan , Peng Jing‐Rong , Zheng Lan , Luo Feng , Liu Hao , Qian Zhi‐Yong
Published: November 2011

The biodegradable polylactide/poly(ethylene glycol) (PLA/PEG) hybrid membranes were fabricated via electrospinning of PLA/PEG solution. Their structures and properties were investigated by scanning electron microscopy, differential scanning calorimetry, and water contact angle. In vitro hydrolytic degradation showed that PEG content influenced the degradation rate of the PLA/PEG hybrid mats. The mechanical property was measured by tensile test and the result revealed that the addition of PEG had an obvious plasticization on PLA matrix. In‐vitro biocompatibility was investigated by culturing cell on the scaffolds and MTT assay. The results indicated that the cell could attach and proliferate on the membranes, so confirmed that the PLA/PEG hybrid membrane had good biocompatibility, and it could be a promising biomaterial for tissue engineering applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Effects of the iron‐chelating agent deferoxamine on triethylene glycol dimethacrylate, 2‐hydroxylethyl methacrylate, hydrogen peroxide‐induced cytotoxicity
Authors: Zhu Tingting , Lim Bum‐Soon , Park Hee Chul , Son Kyung Mi , Yang Hyeong‐Cheol
Published: November 2011

Triethylene glycol dimethacrylate (TEGDMA) and 2‐hydroxylethyl methacrylate (HEMA) are known to deplete glutathione in mammalian cells, generate reactive oxygen species (ROS), and cause oxidative stress. In this study, we investigated whether hydroxyl radicals (·OH), the most lethal and genotoxic ROS, and the Fenton reaction are involved in the cytotoxicity of resin monomers to four different cell types, namely MC3T3‐E1 preosteoblasts, human dental pulp cells (HDPCs), human gingival fibroblasts, and L929 mouse fibroblasts. Deferoxamine (DFO), an iron chelating agent, effectively protected MC3T3‐E1 cells from resin monomer‐induced cytotoxicity, indicating that cytotoxicity was caused primarily by hydroxyl radicals. However, DFO only had a protective effect against relatively high concentrations of TEGDMA and HEMA in HDPCs and human gingival fibroblasts, and resin monomer‐induced cytotoxicity in L929 was not attenuated by DFO. A labile iron pool (LIP) was detectable only in MC3T3‐E1 cells among the four cell types. This indicates that the generation of hydroxyl radicals induced by resin monomers is likely dependent on LIP levels. In contrast to resin monomers, hydrogen peroxide (H2O2)‐induced cytotoxicity was not prevented by DFO in any of the cell types examined, although hydroxyl radicals were detected in MC3T3‐E1 cells and HDPCs on exposure to exogenous H2O2. This result suggests that generation of hydroxyl radicals is not always the primary cause of cytotoxicity in H2O2‐treated cells. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Clearance kinetics of a hylan‐based viscosupplement after intra‐articular and intravenous administration in animal models
Authors: Larsen Nancy E. , Dursema Holly D. , Pollak Cynthia T. , Skrabut Eugene M.
Published: November 2011

Clearance of hylan fluid and hylan gel, components of the hyaluronan (HA)‐derived viscosupplement hylan G‐F 20, following intra‐articular injection into normal, healthy rabbits was evaluated. Radiolabeled hylan G‐F 20 was injected at a volume of 0.3 mL into both knee joints of 12 rabbits. At sacrifice, synovial fluid, joint tissues, blood, popliteal lymph nodes, liver, spleen, kidney, and lung were analyzed for radioactivity. The half‐life of the fluid component, a high‐molecular weight hylan, was 1.5 ± 0.2 days while the half‐life of the hylan gel component, a crosslinked hylan, was 8.8 ± 0.9 days. There was no radioactivity detected in the blood or the major internal organs following intra‐articular injection. A rat model was used to evaluate the clearance of a large intravenous bolus of solubilized hylan gel. No accumulation of hylan gel degradation products was observed in any major organs and the half‐life of hylan elimination from the blood was within normal ranges for HA elimination. The dosing used in the nonclinical rabbit intra‐articular study was equivalent (v/w) to a single 6 mL dose in humans. These results are consistent with the current clinical data that demonstrates safety and effectiveness of an increased volume of hylan G‐F 20 injected into the osteoarthritis knee. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 457–462, 2012.