bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the interactions of quercetin and morin with trypsin
Authors: Zhang Hong‐Mei , Wang Yan‐Qing , Zhou Qiu‐Hua
Published: May 2009

The interactions of quercetin and morin with trypsin were investigated by UV–vis absorption, fluorescence, synchronous fluorescence and three‐dimensional fluorescence spectra techniques under physiological pH 7.40. Quercetin and morin effectively quenched the intrinsic fluorescence of trypsin via static quenching. The process of binding quercetin and morin on trypsin was a spontaneous molecular interaction procedure. The binding constants and thermodynamic parameters at two different temperatures, the binding locality and the binding power were obtained. The conformation of trypsin was discussed by synchronous and three‐dimensional fluorescence techniques. Copyright © 2009 John Wiley & Sons, Ltd.
Venous rupture during percutaneous treatment of hemodialysis fistulas and grafts
Authors: Bittl John A.
Published: May 2009

Objectives: The aim of this study was to analyze the risk and consequences of venous rupture during angioplasty of malfunctioning hemodialysis grafts and fistulas. Background: Venous stenoses in the outflow limb of hemodialysis accesses often require ultra‐high balloon pressure for optimal dilatation. Methods: Baseline characteristics and outcomes were analyzed for a consecutive series of patients treated between 1999 and 2008. Results: Venous rupture or perforation occurred in 11 of 1242 (0.9%) procedures. No patient with a rupture or perforation died or required emergency or urgent surgical repair. Two of 11 patients (18.2%) required transfusions, 8 of 11 patients (72.7%) required stenting, and 6 of 8 (75.0%) who needed stenting received covered stents to achieve hemostasis. Rupture led to access thrombosis within 30 days in 9 of 11 cases (82%). Multivariable logistical regression analysis suggested that using a balloon catheter more than 2 mm larger than the diameter of the hemodialysis access or using peripheral cutting balloons increased the risk of rupture or perforation. Conclusions: Rupture or perforation is a rare complication of treatment of malfunctioning hemodialysis grafts and fistulas. The complication may be managed with nonsurgical methods and might be avoided by optimal balloon selection and sizing. © 2009 Wiley‐Liss, Inc.
Silver(I) Complexes of the Weakly Coordinating Solvents SO2 and CH2Cl2: Crystal Structures, Bonding, and Energetics of [Ag(OSO)][Al{OC(CF3)3}4], [Ag(OSO)2/2][SbF6], and [Ag(CH2Cl2)2][SbF6]
Authors: Decken Andreas , Knapp Carsten , Nikiforov Grigori B. , Passmore Jack , Rautiainen J. Mikko , Wang Xinping , Zeng Xiaoqing
Published: May 2009

Pushing the limits of coordination chemistry: The most weakly coordinated silver complexes of the very weakly coordinating solvents dichloromethane and liquid sulfur dioxide were prepared. Special techniques at low temperatures and the use of weakly coordinating anions allowed structural characterization of [Ag(OSO)][Al{OC(CF3)3}4], [Ag(OSO)2/2][SbF6], and [Ag(Cl2CH2)2][SbF6] (see figure). An investigation of the bonding shows that these complexes are mainly stabilized by electrostatic monopole–dipole interactions.

magnified image

The synthetically useful solvent‐free silver(I) salt Ag[Al(pftb)4] (pftb=OC(CF3)3) was prepared by metathesis reaction of Li[Al(pftb)4] with Ag[SbF6] in liquid SO2. The solvated complexes [Ag(OSO)][Al(pftb)4], [Ag(OSO)2/2][SbF6], and [Ag(CH2Cl2)2][SbF6] were prepared and isolated by special techniques at low temperatures and structurally characterized by single‐crystal X‐ray diffraction. The SO2 complexes provide the first examples of coordination of the very weak Lewis base SO2 to silver(I). The SO2 molecule in [Ag(OSO)][Al(pftb)4] is η1‐O coordinated to Ag+, while the SO2 ligands in [Ag(OSO)2/2][SbF6] bridge two Ag+ ions in an η2‐O,O′ (trans,trans) manner. [Ag(CH2Cl2)2][SbF6] contains [Ag(CH2Cl2)2]+ ions linked through [SbF6]− ions to give a polymeric structure. The solid‐state silver(I) ion affinities (SIA) of SO2 and CH2Cl2, based on bond lengths and corresponding valence units in the corresponding complexes and tensimetric titrations of Ag[Al(pftb)4] and Ag[SbF6] with SO2 vapor, show that SO2 is a weaker ligand to Ag+ than the commonly used weakly coordinating solvent CH2Cl2 and indicated that binding strength of SO2 to silver(I) in the silver(I) salts increases with increasing size of the corresponding counteranion ([Al(pftb)4]−>[SbF6]−). The experimental findings are in good agreement with theoretical gas‐phase ligand‐binding energies of [Ag(L)n]+ (L=SO2, CH2Cl2; n=1, 2) and solid‐state enthalpies obtained from Born–Fajans–Haber cycles by using the volume‐based thermodynamics (VBT) approach. Bonding analysis (VB, NBO, MO) of [Ag(L)n]+ suggests that these complexes are almost completely stabilized by electrostatic interaction, that is, monopole–dipole interaction, with almost no covalent contribution by electron donation from the ligand orbitals into the vacant 5s orbital of Ag+. All experimental findings and theoretical considerations demonstrate that SO2 is less covalently bound to Ag+ than CH2Cl2 and support the thesis that SO2 is a polar but non‐coordinating solvent towards Ag+.
Bilirubin as a determinant for altered neurogenesis, neuritogenesis, and synaptogenesis
Authors: Fernandes Adelaide , Falcão Ana Sofia , Abranches Elsa , Bekman Evguenia , Henrique Domingos , Lanier Lorene M. , Brites Dora
Published: May 2009

Elevated levels of serum unconjugated bilirubin (UCB) in the first weeks of life may lead to long‐term neurologic impairment. We previously reported that an early exposure of developing neurons to UCB, in conditions mimicking moderate to severe neonatal jaundice, leads to neuritic atrophy and cell death. Here, we have further analyzed the effect of UCB on nerve cell differentiation and neuronal development, addressing how UCB may affect the viability of undifferentiated neural precursor cells and their fate decisions, as well as the development of hippocampal neurons in terms of dendritic and axonal elongation and branching, the axonal growth cone morphology, and the establishment of dendritic spines and synapses. Our results indicate that UCB reduces the viability of proliferating neural precursors, decreases neurogenesis without affecting astrogliogenesis, and increases cellular dysfunction in differentiating cells. In addition, an early exposure of neurons to UCB decreases the number of dendritic and axonal branches at 3 and 9 days in vitro (DIV), and a higher number of neurons showed a smaller growth cone area. UCB‐treated neurons also reveal a decreased density of dendritic spines and synapses at 21 DIV. Such deleterious role of UCB in neuronal differentiation, development, and plasticity may compromise the performance of the brain in later life. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009
Synthesis and Cytotoxicity Studies of Fluorinated Derivatives of Vanadocene Y
Authors: Gleeson Brendan , Claffey James , Deally Anthony , Hogan Megan , Méndez Luis Miguel Menéndez , Müller‐Bunz Helge , Patil Siddappa , Wallis Denise , Tacke Matthias
Published: May 2009

From the reaction of 6‐(2‐fluoro‐4‐methoxyphenyl)fulvene (1a), 6‐(3‐fluoro‐4‐methoxyphenyl)fulvene (1b) and 6‐[4‐(trifluoromethoxy)phenyl]fulvene (1c) with LiBEt3H, lithiated cyclopentadienide intermediates (2a–c) were synthesised. These intermediates were then transmetallated to vanadium with VCl4 to yield the benzyl‐substituted vanadocenes bis[(2‐fluoro‐4‐methoxybenzyl)cyclopentadienyl]vanadium(IV) dichloride (3a), bis[(3‐fluoro‐4‐methoxybenzyl)cyclopentadienyl]vanadium(IV) dichloride (3b), and bis[(4‐trifluoromethoxybenzyl)cyclopentadienyl]vanadium(IV) dichloride (3c). The three vanadocenes 3a–c were characterised by single‐crystal X‐ray diffraction. All three vanadocenes had their cytotoxicity investigated through MTT‐based preliminary in‐vitro testing on the LLC‐PK and Caki‐1 cell lines in order to determine their IC50 values. Vanadocenes 3a–c were found to have IC50 values of 6.0 (+/–4), 35 (+/–7) and 13 (+/–3) μM on the LLC‐PK cell line and IC50 values of 78 (+/–11), 18 (+/–16) and 2.2 (+/–0.5) μM on the Caki‐1 cell line respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
STAT3 activation contributes directly to Epstein‐Barr virus–mediated invasiveness of nasopharyngeal cancer cells in vitro
Authors: Lui Vivian Wai Yan , Wong Elaine Yue Ling , Ho Yeung , Hong Bo , Wong Sze Chuen Cesar , Tao Qian , Choi Gigi Ching Gee , Au Thomas Chi Chuen , Ho Kakiu , Yau Daisy Mei Sze , Ma Brigette Buig Yue , Hui Edwin Pun , Chan Andrew Sai‐Kit , Tsang Chi‐Man , Tsao Sai‐Wah , Grandis Jennifer Rubin , Chan Anthony Tak‐Cheung
Published: May 2009

Nasopharyngeal cancer (NPC) is an Epstein‐Barr virus (EBV)‐associated head and neck cancer prevalent in Asia. Although with reasons not fully understood, the intrinsic invasiveness of NPC is believed to be EBV‐linked. Recently, EBV was found to induce STAT3 activation. Constitutive STAT3 activation correlated with advanced clinical staging in NPC. We hypothesized that STAT3 activation by EBV directly contributes to the intrinsic invasiveness of NPC cells. Phospho‐STAT3‐Tyr705 was detected in high percentage of NPC tumors (7/10 cases). Using a paired NPC cell line model, HONE‐1 and the EBV‐infected counterpart, HONE‐1‐EBV, we found that HONE‐1‐EBV expressed a higher level of phospho‐STAT3‐Tyr705 and was ∼11‐fold more invasive than HONE‐1. In HONE‐1‐EBV, STAT3 siRNA targeting inhibited both spontaneous and serum‐induced invasion, as well as cell growth. Conversely, activation of STAT3 (by expressing an activated STAT3 mutant, namely STAT3C) in the parental HONE‐1, mimicking EBV‐induced STAT3 activation, significantly enhanced its invasiveness and proliferation, which was accompanied by increased expression of markers of mesenchymal status, proliferation and anti‐apoptosis. Our results demonstrated that EBV‐induced STAT3 activation is responsible for NPC cell proliferation and invasion. This was further confirmed by a small molecule inhibitor of JAK/STAT3, JSI‐124. JSI‐124 inhibited STAT3 activation in HONE‐1‐EBV, with subsequent growth inhibition, induction of PARP cleavage, abrogation of anchorage‐independent growth and invasion. We found that EBV‐independent activation of STAT3 by a growth factor, EGF, also contributed to NPC invasion. In conclusion, EBV‐induced STAT3 activation directly contributes to the intrinsic invasiveness of NPC cells and STAT3 targeting may be beneficial in treating aggressive NPC. © 2009 UICC
The nonexistence of a (K6‐e)‐decomposition of the complete graph K29
Authors: Hartke S. G. , Östergård P. R. J. , Bryant D. , El‐Zanati S. I.
Published: May 2009

We show via an exhaustive computer search that there does not exist a (K6−e)‐decomposition of K29. This is the first example of a non‐complete graph G for which a G‐decomposition of K2|E(G)|+1 does not exist. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 94–104, 2010
Free‐shape 14C age–depth modelling of an intensively dated modern peat profile
Authors: Goslar Tomasz , Van Der Knaap Willem O. , Kamenik Christian , Van Leeuwen Jacqueline F. N.
Published: May 2009

The paper presents a new algorithm for finding the best‐fit age–depth model of a peat profile dated with 14C. This algorithm of free‐shape modelling is useful when the age–depth curve is wiggly and difficult to approximate by a simple mathematical function. The performance of the free‐shape algorithm is illustrated with the example of the MA2 peat profile from Mauntschas mire, using 29 radiocarbon dates spanning the last 1300 a, and where the age–depth curve revealed a relatively complicated shape.

The best‐fit age–depth model searched for is a curve maximising the ‘Fit quality’, defined as a combination of fit of 14C dates to the radiocarbon calibration curve, general smoothness of the age–depth line, and similarity of relative changes in the modelled sediment accumulation rates to those suggested by independent data. The algorithm of free‐shape age–depth modelling searched for a reasonable equilibrium or compromise between the conditions above. Uncertainty of the free‐shape model was assessed with a Monte Carlo Markov chain built from large number of age–depth lines accepted with probabilities dependent on the ‘fit quality’ defined as above.

Parallel fluctuations in concentrations of most pollen taxa in MA2 strongly suggest a complicated shape of the age–depth curve, which is supported in the upper part of the profile by the record of spheroidal carbonaceous particles, and in some levels also by the 14C dates. A modification of total pollen concentrations was therefore used as a quantitative indicator of relative changes of the peat accumulation rate. The use of pollen concentrations improved the fit of the 14C dates in several cases.

Application of the final age–depth model to the pollen data resulted in a diagram of pollen accumulation which allows interpretation in ecological terms, whereas age–depth models that did not use pollen concentrations led to problematic and confusing results. The obtained age–depth model is therefore accepted as a good approximation of the actual conditions. Copyright © 2009 John Wiley & Sons, Ltd.
Investigation of the effect of CrO and MoO on carbon steel corrosion using AFM and electrochemical techniques
Authors: Chen Z. , Guo X. , Zhang X. , Huang L.
Published: May 2009

The effect of chromate (${\rm CrO}_4^{2 - }$) and molybdate (${\rm MoO}_4^{2 - }$) ions on the corrosion of carbon steel in 0.5 M NaCl solution has been studied using electrochemical measurements and atomic force microscopy (AFM) technique. Potentiodynamic polarization data suggest that both ${\rm CrO}_4^{2 - }$ and ${\rm MoO}_4^{2 - }$ have inhibition effect on carbon steel corrosion, and the inhibition efficiency increases with increase in concentrations of ${\rm CrO}_4^{2 - }$ and ${\rm MoO}_4^{2 - }$; at the same concentration, the inhibition efficiency of ${\rm CrO}_4^{2 - }$ is higher than that of ${\rm MoO}_4^{2 - }$. The increase in concentrations of ${\rm CrO}_4^{2 - }$ and ${\rm MoO}_4^{2 - }$ anions causes a shift of the breakdown potential (Eb) in the positive direction, indicating the inhibitive effect of the added anions on the pitting attack. At the same concentrations, the breakdown potential of ${\rm CrO}_4^{2 - }$ is higher than that of ${\rm MoO}_4^{2 - }$. Electrochemical impedance spectroscopy (EIS) tests reveal that the charge transfer resistance and passive film resistance increase with increase in concentrations of ${\rm CrO}_4^{2 - }$ or ${\rm MoO}_4^{2 - }$; at the same concentrations, as for ${\rm CrO}_4^{2 - }$ the charge transfer resistance and passive film resistance were bigger than those of ${\rm MoO}_4^{2 - }$. AFM imaging technique shows that local corrosion was inhibited obviously after the addtion of ${\rm CrO}_4^{2 - }$ or ${\rm MoO}_4^{2 - }$, and passive film of ${\rm CrO}_4^{2 - }$ was much more compact than that of ${\rm MoO}_4^{2 - }$. AFM force–distance curves indicate that the passive film of ${\rm CrO}_4^{2 - }$ is much stiffer than that of ${\rm MoO}_4^{2 - }$.
Influence of laser‐glazing on hot corrosion resistance of yttria‐stabilized zirconia TBC in molten salt mixture of V2O5 and Na2SO4
Authors: Zhong X. , Wang Y. , Xu Z. , Zhang Y. , Zhang J. , Cao X.
Published: May 2009

Plasma‐sprayed 8YSZ (zirconia stabilized with 8 wt% yttria)/NiCoCrAlYTa thermal barrier coatings (TBCs) were laser‐glazed using a continuous‐wave CO2 laser. Open pores within the coating surface were eliminated and an external densified layer was generated by laser‐glazing. The hot corrosion resistances of the plasma‐sprayed and laser‐glazed coatings were investigated. The two specimens were exposed for the same period of 100 h at 900 °C to a salt mixture of vanadium pentoxide (V2O5) and sodium sulfate (Na2SO4). Serious crack and spallation occurred in the as‐sprayed coating, while the as‐glazed coating exhibited good hot corrosion behavior and consequently achieved a prolonged lifetime. The results showed that the as‐sprayed 8YSZ coating achieved remarkably improved hot corrosion resistance by laser‐glazing. Changes in the coatings were studied by scanning electron microscopy (SEM) to observe the microstructure and X‐ray diffraction (XRD) technique to analyze the phase composition. XRD results showed that the reaction between yttria (Y2O3) and V2O5 produced yttrium vanadate (YVO4), leaching Y2O3 from YSZ and causing the progressive destabilization transformation from the tetragonal (t) to monoclinic (m) phase. The external dense layer produced by laser‐glazing restrained the penetration of the molten salt, to a certain extent, into the coating, which led to a relatively low m‐ZrO2 content in the coating after the hot corrosion test. Additionally, the segmented cracks in the coating surface induced by laser‐glazing were helpful to the improvement of strain tolerance of the coating. The two factors were important contributions to the significant enhancement of hot corrosion resistance of the as‐glazed YSZ coating.
Corrosion monitoring of hydrogen by HUP probe in the presence of sulphide and thiourea
Authors: Abbassi A. , Mihi A. , Benbouta R.
Published: May 2009

The effect of sulphide and thiourea on hydrogen uptake during the corrosion of steel in deaerated pH3 has been studied using an electrochemical hydrogen probe incorporating a solid electrolyte (HUP) and lead dioxide (PbO2) as a reference electrode. This probe has been used for the quantitative determination of the hydrogen activity generated during the corrosion of steel. The sensor voltage implies an average equivalent hydrogen pressure in uncharged steel of 2 × 10−18 atmospheres. During the corrosion of steel, this value increases by very large amounts; thus in deaerated pH3, the equivalent pressure rose by 1024.5 in the presence of 200 ppm sulphide and by 102 in the presence of 100 ppm thiourea. Weight loss and AC impedance methods were also performed under the same conditions as the hydrogen measurements. The hydrogen probe data were correlated with a.c impedance and weight loss results in order to understand the effect of S2− and thiourea on hydrogen uptake.
Cluster secondary ion mass spectrometry of polymers and related materials
Authors: Mahoney Christine M.
Published: May 2009

Cluster secondary ion mass spectrometry (cluster SIMS) has played a critical role in the characterization of polymeric materials over the last decade, allowing for the ability to obtain spatially resolved surface and in‐depth molecular information from many polymer systems. With the advent of new molecular sources such as ${\rm C}_{60}^ +$, ${\rm Au}_3^ +$, ${\rm SF}_5^ +$, and ${\rm Bi}_3^ +$, there are considerable increases in secondary ion signal as compared to more conventional atomic beams (Ar+, Cs+, or Ga+). In addition, compositional depth profiling in organic and polymeric systems is now feasible, without the rapid signal decay that is typically observed under atomic bombardment. The premise behind the success of cluster SIMS is that compared to atomic beams, polyatomic beams tend to cause surface‐localized damage with rapid sputter removal rates, resulting in a system at equilibrium, where the damage created is rapidly removed before it can accumulate. Though this may be partly true, there are actually much more complex chemistries occurring under polyatomic bombardment of organic and polymeric materials, which need to be considered and discussed to better understand and define the important parameters for successful depth profiling. The following presents a review of the current literature on polymer analysis using cluster beams. This review will focus on the surface and in‐depth characterization of polymer samples with cluster sources, but will also discuss the characterization of other relevant organic materials, and basic polymer radiation chemistry. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:247–293, 2010
Toughening and brittle‐tough transition in blends of an amorphous polyamide with a modified styrene/ethylene‐butylene/styrene triblock copolymer
Authors: González I. , Eguiazábal J.I. , Nazábal J.
Published: May 2009

Amorphous polyamide (aPA)/maleated styrene/ethylene‐butylene/styrene triblock copolymer (mSEBS) blends with a mSEBS content up to 25% were obtained in the melt state with the aim of toughening the notch sensitive pseudoductile matrix, and of studying the parameters that influence the morphology that leads to the brittle/tough transition. The increase in the Tg of the rubbery phase, which depended on the maleinized copolymer content, indicated the presence of reacted copolymers. These copolymers should decrease the interfacial tension, thus allowing the presence of a fine dispersed particle size. The impressive (27‐fold) toughness increase observed, which is among the largest observed in toughened blends, took place at 15% mSEBS content. The critical interparticle distance (τc) of the blends was smaller than that of polyamide 6 (PA6)/mSEBS blends tested at the same conditions. Having ruled out the possible influence of other parameters, the lower τc of the aPA/mSEBS blends of this study is attributed to their higher interfacial adhesion that was inferred by the calculation of the solubility parameters and by the measured interfacial toughness. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Mechanism of interactions of eggshell microparticles with epoxy resins
Authors: Ji Genzhong , Zhu Hongqi , Qi Chenze , Zeng Minfeng
Published: May 2009

Large surface‐area microparticles of natural chicken eggshell were prepared and characterized to illustrate how such particles can improve the toughness of epoxy resins. A small amount of organic compounds, in particular proteins, were found to be present in the microparticles and beneficial to the enhancement of the mechanical properties of the epoxy resins. Scanning electron microscopic analysis of the rough fracture surfaces show that there are full of plastic deformation, voids, cavities, and debonding phenomena in the microparticle‐filled composites. Positron annihilation study indicates that the lifetime of τ3 o‐Ps varies and the corresponding intensity of I3 becomes weak with the increase of eggshell particle content, which indicates that there is a good interaction between the epoxy resin and the filling particles. This gives rise to significant improvement in the toughness of the filled resin. The impact strength of the epoxy resin composite reaches 16.7 kJ/m2 compared with 9.7 kJ/m2 of neat epoxy resin when the epoxy resin composite is filled with only 5 mass% eggshell particles. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
The effect of poly(vinyl alcohol) hydrolysis on the properties of its blends with nylon 6
Authors: Cui Li , Fu Qiang , Chang Chang‐jung , Yeh Jen‐taut
Published: May 2009

An investigation of the properties of the blends of nylon 6 (PA6) and poly(vinyl alcohol) (PVA) with varying degrees of hydrolysis was conducted. A near disappearance of the characteristics of the α‐form PVA crystals, crystallization exotherms, and hydrogen‐bonded hydroxyl groups and the tensile properties originally associated with the PVA molecules of PA6xPVA PA6xPVA, and PA6xPVA specimens was observed as the PVA contents of the specimens became equal to or less than their corresponding ‘‘critical’’ values at 16.7 wt%, 33.3 wt%, and 50 wt%, respectively. These results support the idea that PVA molecules are miscible with PA6 molecules to some extent at the molecular level as the PVA contents of the blends become equal to or less than their corresponding critical PVA contents. In this article, we have proposed the possible reasons accounting for these properties of the PA6xPVAy series specimens with a varying degree of hydrolysis. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Steady‐state viscoelastic flow simulation of polymer melts in a rotational‐type rheometer
Authors: Tanoue Shuichi , Zielinski Michal K. , Iemoto Yoshiyuki
Published: May 2009

Polymer samples in the jigs begins to protrude when the heat is turned up when we measure the rheological characteristics of polymer melts using rotational‐type rheometers, such as parallel and cone‐and‐plate types. To clarify the effects of this protruding part on the obtained rheological data, we tried to evaluate the rotational‐type rheometer by a non‐isothermal viscoelastic flow simulation using the finite element method. The multiple mode Phan‐Thien Tanner (PTT) model was employed as the constitutive equation. As a result, the shear viscosity in the steady state increases with the size of the protruding part of the polymer melt specimen at the same shear rate in case with a parallel plate and a cone‐and‐plate type rheomters. In contrast, the deviation of the primary normal stress difference between the estimated value from the simulation results and the data from the PTT model is almost independent of the size of the protruding part with the cone‐and‐plate type rheometer. In addition, the deviations of the primary normal stress difference with a parallel plate rheometer increase with the protruding part size. However, these deviations are smaller than those of shear viscosity. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Enhancing thermal, electrical efficiencies of a miniature combustion‐driven thermophotovoltaic system
Authors: Li Yueh‐Heng , Li Hong‐Yuan , Dunn‐Rankin Derek , Chao Yei‐Chin
Published: May 2009

Methods to enhance the thermal and electrical efficiencies through novel design of combustion and thermal management of the combustor in a miniature thermophotovoltaic (TPV) system are proposed, discussed, and demonstrated in this paper. The miniature TPV system consists of a swirling combustor surrounded by GaSb PV cell arrays. The swirl combustor design, along with a heat‐regeneration reverse tube and mixing‐enhancing porous‐medium fuel injection, improves the low illumination and incomplete combustion problems associated with typical miniature TPV systems. A reverse tube is used to enforce swirling flame attachment to the inner wall of the emitter by pushing the swirl recirculation zone back into the chamber and simultaneously redirecting the hot product gas for reheating the outer surface of the emitter. The porous medium fuel injector is used as a fuel/air mixing enhancer and as a flame stabilizer to anchor the flame. The miniature TPV system, using different combustor configurations, is tested and discussed. Results indicate that the proposed swirling combustor with a reverse tube and porous medium can improve the intensity and uniformity of the emitter illumination, and can increase the thermal radiant efficiency. Consequently, the overall thermal efficiency and electrical output of the miniature TPV system are greatly enhanced. Copyright © 2009 John Wiley & Sons, Ltd.
Preventive screening for early readers: Predictive validity of the Dynamic Indicators of Basic Early Literacy Skills (DIBELS)
Authors: Goffreda Catherine T. , Diperna James Clyde , Pedersen Jason A.
Published: May 2009

Current empirical evidence indicates poor learning trajectories for students with early literacy skill deficits. As such, reliable and valid detection of at‐risk students through regular screening and progress monitoring is imperative. This study investigated the predictive validity of scores on the Dynamic Indicators of Basic Early Literacy Skills (DIBELS). Logistic regression analyses were used to test the utility of the DIBELS first grade indicators for predicting reading proficiency on TerraNova California Achievement Test (CAT) Assessment and Pennsylvania System of School Assessment (PSSA) in second and third grade, respectively. Results suggest that students' first grade Oral Reading Fluency (ORF) DIBELS risk category scores were the only significant predictor of future TerraNova and PSSA reading proficiency. Although the current data present encouraging results for the predictive validity of ORF as a screening tool for early readers, further investigations of the utility of the remaining indicators (Letter Naming Fluency, Nonsense Word Fluency, and Phonemic Segmentation Fluency) are warranted. © 2009 Wiley Periodicals, Inc.
Green polymer chemistry using nature's catalysts, enzymes
Authors: Puskas Judit E. , Sen Mustafa Y. , Seo Kwang Su
Published: May 2009

The use of enzymes as catalysts for organic synthesis has become an increasingly attractive alternative to conventional chemical catalysis. Enzymes offer several advantages including high selectivity, ability to operate under mild conditions, catalyst recyclability, and biocompatibility. Although there are many examples in the literature involving enzymes for the synthesis of polymers, our search showed that very little had been done in the area of polymer modification. In this article, we will discuss enzyme catalysis in general and highlight our recent results concerning precision polymer functionalization using enzymatic catalysis—“green polymer chemistry.” © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2959–2976, 2009
Solvent‐induced self‐assembly in cardanol‐based urethane methacrylate comb polymers
Authors: Rekha N. , Asha S. K.
Published: May 2009

We report side chain urethane–methacrylate comb polymers based on the renewable resource cardanol and its saturated analogue 3‐pentadecyl phenol and their self‐assembly into pores, spheres, vesicles, tubes, and so forth. The monomers were synthesized in one pot by coupling 1 equiv. of isophorone diisocyanate with 1 equiv. of cardanol/pentadecyl phenol followed by coupling with 1 equiv. of hydroxyethyl methacrylate. They were polymerized free radically using benzoyl peroxide as the initiator and were characterized by NMR and FTIR, and their molecular weights were determined by gel permeation chromatography. The unique polymer design had sites for self‐organization via hydrogen bonding of the side chain urethane units, π–π stacking interactions of the aromatic units as well as interdigitation of the long C15 alkyl side chains in the polymer. The morphologies of solvent cast polymer films were studied using microscopic techniques such as scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The polymers exhibited three‐dimensional honeycomb morphology in CHCl3, whereas in tetrahydrofuran, they formed spheres. The direct cardanol‐derived polymer PCIH showed a tendency for multiple morphologies such as spheres and tubes in tetrahydrofuran. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2996–3009, 2009
Functional syndiotactic poly(β‐hydroxyalkanoate)s via stereoselective ring‐opening copolymerization of rac‐β‐butyrolactone and rac‐allyl‐β‐butyrolactone
Authors: Ajellal Noureddine , Thomas Christophe M. , Carpentier Jean‐François
Published: May 2009

The copolymerization of racemic β‐butyrolactone (rac‐BLMe) with racemic “allyl‐β‐butyrolactone” (rac‐BLallyl) in toluene, catalyzed by the discrete amino‐alkoxy‐bis(phenolate) yttrium‐amido complex 1, gave new poly(β‐hydroxyalkanoate)s with unsaturated side chains. The poly(BLMe‐co‐BLallyl) copolymers produced have a highly syndiotactic backbone structure (Pr = 0.80–0.84) with a random enchainment of monomer units, as evidenced by 13C NMR, and high molecular weight (Mn up to 58,000 g mol−1) with a narrow polydispersity (Mw/Mn = 1.07–1.37), as determined by GPC. The comonomer incorporation (5–50 mol % rac‐BLallyl) was a linear function of the feed ratio. The pendant vinyl bond of the side‐chains in those poly(BLMe‐co‐BLallyl) copolymers allowed the effective introduction of hydroxy or epoxy groups via dihydroxylation, hydroboration‐oxidation or epoxidation reactions. NMR studies indicated that all of these transformations proceed in an essentially quantitative conversion and do not affect the macromolecular architecture. Some thermal properties (Tm, ΔHm, Tg) of the prepared polymers have been also evaluated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3177–3189, 2009
Perilla leaf extract ameliorates obesity and dyslipidemia induced by high‐fat diet
Authors: Kim Mi‐Ja , Kim Hye Kyung
Published: May 2009

The objective of this study was to evaluate the antiobesity effect of perilla leaf extract (PLE) in animal models of high fat diet‐induced obesity. C57BL/6J mice were fed a standard diet (STD) or high fat diet (HFD) for 5 weeks to induce obesity. The experimental groups were four groups with 10 mice per group and fed for 4 weeks: a STD group, a HFD group, a HFD containing 1% PLE (HFD + PLE 1%) group and a HFD containing 3% PLE (HFD + PLE 3%) group. The PLE supplementation significantly decreased body weight gain, food efficiency ratio, and relative liver and epididymal fat mass compared with those of the HFD group. Also, triglyceride, total cholesterol and LDL levels in the plasma were significantly reduced by PLE supplementation compared with the HFD group. Histological changes in the liver of the PLE supplemented group showed an inhibition of steatosis induced by HFD. Furthermore, PLE reversed the HFD induced changes in the expression patterns of epididymal adipose tissue genes: acetyl CoA carboxylase (ACC), glycerol‐3‐phosphate dehydrogenase (GPDH) and peroxisome proliferator‐activated receptor γ (PPARγ). These results suggest that the PLE supplement suppressed body weight gain and improved the blood lipid profiling, in part by down‐regulating adipogenic transcription factor and other specific target genes. Copyright © 2009 John Wiley & Sons, Ltd.
Computer‐assisted automatic localization of the human pedunculopontine nucleus in T1‐weighted MR images: a preliminary study
Authors: Fu Yili , Gao Wenpeng , Zhu Minwei , Chen Xiaoguang , Lin Zhiguo , Wang Shuguo
Published: May 2009

Background

The pedunculopontine nucleus (PPN) is a new promising target of deep brain stimulation (DBS) for the treatment of Parkinson's disease. This study was to develop a method of computer‐assisted automatic localization of the PPN in T1‐weighted MR images.

Methods

A 3D template of a segment of the brainstem containing the PPN was constructed. A knowledge‐based, hierarchical method of template‐to‐subject registration was proposed to register the template to the subject's data to locate the subject's PPN.

Results

Experiments were performed with both T1‐weighted and proton density MR images acquired from 12 people. Preliminary results show that the proposed method can locate the PPN with an error of 1.83 ± 0.42 mm for its rostral pole and 1.57 ± 0.34 mm for its caudal pole.

Conclusion

The proposed method is automatic, robust and accurate in the localization of the PPN, which demonstrates utility for preoperative surgical planning. Copyright © 2009 John Wiley & Sons, Ltd.
Insulin-Secreting Cells from Human Eyelid-Derived Stem Cells Alleviate Type I Diabetes in Immunocompetent Mice
Authors: Kang Hyun Mi , Kim Jiyoung , Park Seah , Kim Jinyoung , Kim Haekwon , Kim Kyung Sik , Lee Eun Jig , Seo Sung Ig , Kang Sung Goo , Lee Jong-Eun , Lim Hyunjung
Published: May 2009

Various attempts have been made to develop stem cell-based therapy to alleviate type I diabetes using animal models. However, it has been a question whether human insulin produced from explanted cells is solely responsible for the normoglycemia of diabetic animals. In this study, we isolated neural crest-like stem cells from the human eyelid fat and examined their therapeutic potentials for diabetes. The human eyelid adipose-derived stem cells (HEACs) displayed characteristics of neural crest cells. Using a two-step culture condition combined with nicotinamide, activin, and/or GLP-1, we differentiated HEACs into insulin-secreting cells and examined in vivo effects of differentiated cells by transplantation experiments. Following differentiation in vitro, HEACs released insulin and c-peptide in a glucose-dependent manner. Upon their transplantation under kidney capsules of streptozotocin-treated immunocompetent mice, we observed normalization of hyperglycemia in 10 of 20 recipient mice until sacrifice after 2 months. Only the human, but not the mouse, insulin and c-peptide were detected in the blood of recipient mice. Removal of the kidneys transplanted with HEACs resulted in a sharp increase of blood glucose level. Removed kidney tissues showed distinct expression of various human genes including insulin, and colocalization of the human insulin and the human nuclear protein in many cells. However, they showed diminished or null expression of some immune-related genes. In conclusion, human insulin alone produced from eyelid-derived stem cells following differentiation into insulin-secreting cells and transplantation could normalize type I diabetes in mice.

Disclosure of potential conflicts of interest is found at the end of this article.
In vivo and in vitro toxicity of decabromodiphenyl ethane, a flame retardant
Authors: Nakari Tarja , Huhtala Sami
Published: May 2009

Toxicity of a relative new flame retardant, namely decabromodiphenyl ethane (DBDPE), marketed as an alternative to decabromodiphenyl ether (BDE‐209) was assessed both in vivo and in vitro using the freshly separated fish hepatocyte assay and standardized water flea and zebrafish egg‐larvae tests. The fish hepatocyte assay, based on the synthesis and secretion of vitellogenin from isolated male liver cells produced a clear dose‐response curve in the presence of DBDPE. DBDPE induced the induction of hepatic ethoxyresorufin‐O‐deethylase (EROD) activity at low test concentrations, but started to inhibit the activity at higher concentrations. Also, the induction of the hepatocyte conjugation activity, uridinediphosphoglucuronosyltransferase (UDPGT), was induced with no signs of inhibition even at the highest test concentration. The reduced EROD activity resulted in a drop in the production of vitellogenin by the cells. In vivo tests showed that DBDPE was acutely toxic to water fleas, the 48 h EC‐50 value being 19 μg/L. Moreover, DBDPE reduced the hatching rates of exposed zebra‐fish eggs and raised significantly the mortality of hatched larvae. Because there is hardly any information available on the effects of DBDPE on the aquatic environments, it is crucial to obtain more data on the effects and effective concentrations of DBDPE along with its occurrence in the environment. Such data would enable reliable assessments of the risks posed by this flame retardant. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 333–338, 2010.
Metal distributions in Tigriopus brevicornis (Crustacea, Copepoda) exposed to copper, zinc, nickel, cadmium, silver, and mercury, and implication for subsequent transfer in the food web
Authors: Barka Sabria , Pavillon Jean‐François , Amiard‐Triquet Claude
Published: May 2009

The marine copepod Tigriopus brevicornis is a benthic microcrustacean inhabiting splashed rock pools in the intertidal zone. The genus has a worldwide distribution, and some species play an important role as a link in trophic webs. It is well established that many crustaceans are able to survive in contaminated environments by storing metallic pollutants in detoxified form, and thus, they may represent a source of contaminants for their predators. The present study was designed to determine the distribution of bioaccumulated metals, both essential and nonessential, with a view to assessing their availability to the next trophic level. Groups of 1000–1500 adult copepods were exposed for 1–14 days to Ag, Cd, Cu, Hg, Ni, and Zn in water. Three concentrations, chosen to be realistic in comparison with those encountered in polluted environments, were tested for each metal. Copepods were homogenized and metals were analyzed in supernatants (i.e., metals stored in soluble form in soft tissues or easily remobilized from the exoskeleton) and pellets (including metal‐rich detoxificatory granules or with cellular debris) recovered after centrifugation. Another experiment, consisting of desorption tests, was designed to evaluate the fraction of metals loosely bound onto the exoskeleton. The bioaccumulation ability is highly variable, as shown by the ratios between the concentrations reached in T. brevicornis experimentally exposed to different metals (at higher dose and at day 14) and those in controls (7, 12, 18, 26, 53, and 99, respectively, for Zn, Cu, Ni, Cd, Ag, and Hg). Cu, Zn, and Ni concentrations in copepods increased linearly with time over the whole range of exposure concentrations, whereas a plateau body metal concentration was reached with time particularly at the highest exposure concentrations for Cd, Ag, and Hg. Metals bound onto the exoskeleton were remobilized to different extents, the percentages of desorption being 11, 14, 16, 19, 31, and 32, respectively, for Zn, Cd, Cu, Ni, Ag, and Hg. Metals mainly present in the supernatant (Cd, Ni, Zn) are probably more able to be transferred along a food chain than those which were equally distributed between soluble and insoluble fractions (Ag, Cu, and Hg). © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 350–360, 2010.
Heuristic RAT selection policy to minimize call blocking probability in next generation wireless networks
Authors: Falowo Olabisi E. , Chan H. Anthony
Published: May 2009

In next generation wireless network (NGWN) where multiple radio access technologies (RAT) co‐exist, a joint call admission control (JCAC) algorithm is needed to make a RAT selection decision for each arriving call. RAT selection policy has a significant effect on the overall new call blocking probability in the network. We propose a heuristic RAT selection policy to minimize new call blocking probability in NGWN. The proposed JCAC scheme measures the arrival rate of each class of calls in the heterogeneous wireless network. Based of the measured values of the arrival rates and using linear programming technique, the JCAC scheme determines the RAT selection policy that minimizes overall call blocking probability in the heterogeneous wireless network. Using Markov decision process, we develop an analytical model for the JCAC scheme, and derive new call blocking probability, handoff call dropping probability (HCDP), and call incompletion probability (CIP). Performance of the proposed scheme is compared with the performance of other JCAC scheme. Simulation results show that the proposed scheme reduces new call blocking probability, HCDP, and CIP in the heterogeneous wireless network. Copyright © 2009 John Wiley & Sons, Ltd.
The Repeat Use of a Filling/Voiding Cystometrogram Does Not Alter the Urodynamic Diagnosis in Adults with Idiopathic Detrusor Overactivity
Authors: McEleny Kevin , Leonard Ann , Hasan Tahseen S.
Published: May 2009

Objectives:

The natural history of idiopathic detrusor overactivity (IDO) is poorly understood. The precise role of cystometry in the long-term management of IDO remains unclear. We hypothesized that repeat cystometry in adults with the OAB syndrome, in whom a urodynamic diagnosis of IDO had already been made, would not lead to a change in the urodynamic diagnosis.

Patients and methods:

Departmental records were reviewed retrospectively and adult patients who had undergone cystometry more than once, and received a diagnosis of IDO on their initial CMG were included. Patients who had received a urodynamic diagnosis of neurogenic DO, BOO or urodynamic SUI were excluded as were patients who had undergone a reconstructive or bladder outlet procedure following their initial CMG. The urodynamic traces were re-evaluated to determine if the urodynamic diagnosis had changed.

Results:

50 patients were identified and used in the analysis. The mean interval between first and last CMG was 55.9 months. The same qualitative urodynamic diagnosis was found in 48 out of 50 cases ( p= 1.19×10−40 using Student's t-test).

Conclusions:

The urodynamic findings of IDO persist in the long-term, and in the absence of a significant change in symptoms, such repeat urodynamics are unlikely to yield additional information, even at intervals of several years.
Differential immunodetection of l‐DOPA decarboxylase and tyrosine hydroxylase in the vertebrate retina
Authors: Taveira da Silva Rosilane , Hokoç Jan Nora , de Mello Fernando Garcia , Gardino Patrícia Franca
Published: May 2009

The immunocytochemical staining of l‐DOPA decarboxylase (DDC) and tyrosine hydroxylase (TH) in cells of the developing avian retina and in cells of the retina of adult rats and opossum were compared. DDC was identified at embryonic day 8 in the chick, in cells in the inner nuclear layer (INL). At embryonic day 13, two types of DDC positive cells were observed; type 1, with the soma located in the innermost layer of the INL; and type 2, with the soma located two cell rows from the innermost part of the INL. Immunolabeling for DDC in the presumptive outer plexiform layer was more clearly defined at embryonic day 19 and at post‐hatched day 7. Processes of DDC labeled cells extended into the inner plexiform layer, supporting the amacrine identity of these cells. Dot‐blot analysis revealed that DDC could be detected at embryonic day 4. Confocal microscopy showed that at embryonic day 10, DDC positive cells, but not TH positive cells, were found. After embryonic day 13, cells immunolabeled for DDC and DDC plus TH were detected. The mean density of DDC positive cells quantified in whole‐mounted chick retinas showed that in all stages the density of DDC positive cells exceeded that of TH positive cells by 10–13‐fold. As for the avian retina, density of DDC positive cells in opossum and rat retinas exceeded the density of TH positive cells. In opossum, Müller fibers were also clearly labeled for DDC but not for TH. We propose the hypothesis that the dopamine synthesis in the developing avian retina as well as in the mature rat and opossum tissue is greater than would be expected from TH staining alone.
Fatigue in Post‐poliomyelitis Syndrome: Association With Disease‐Related, Behavioral, and Psychosocial Factors
Authors: Trojan Daria A. , Arnold Douglas L. , Shapiro Stan , Bar‐Or Amit , Robinson Ann , Le Cruguel Jean‐Pierre , Narayanan Sridar , Tartaglia Maria C. , Caramanos Zografos , Da Costa Deborah
Published: May 2009

Objective

To determine the biopsychosocial correlates of general, physical, and mental fatigue in patients with postpoliomyelitis syndrome (PPS) by assessing the additional contribution of potentially modifiable factors after accounting for important nonmodifiable disease‐related factors. It was hypothesized that disease‐related, behavioral, and psychosocial factors would contribute in different ways to general, physical, and mental fatigue in PPS and that a portion of fatigue would be determined by potentially modifiable factors.

Design

Cross‐sectional study.

Setting

A tertiary university‐affiliated hospital post‐polio clinic.

Patients

Fifty‐two ambulatory patients with PPS who were not severely depressed were included.

Assessment of Risk Factors

Potential correlates for fatigue included disease‐related factors (acute polio weakness, time since acute polio, PPS duration, muscle strength, pain, forced vital capacity, maximum inspiratory pressure, maximum expiratory pressure, body mass index, disability, fibromyalgia), behavioral factors (physical activity, sleep quality), and psychosocial factors (depression, stress, self‐efficacy).

Main Outcome Measurements

Fatigue was assessed with the Multidimensional Fatigue Inventory (MFI; assesses fatigue on 5 subscales) and the Fatigue Severity Scale (FSS).

Results

Multivariate models were computed for MFI General, Physical, and Mental Fatigue. Age‐adjusted multivariate models with nonmodifiable factors included the following predictors of (1) MFI General Fatigue: maximum inspiratory pressure, fibromyalgia, muscle strength; (2) MFI Physical Fatigue: maximum expiratory pressure, muscle strength, age, time since acute polio; and (3) MFI Mental Fatigue: none. The following potentially modifiable predictors made an additional contribution to the models: (1) MFI General Fatigue: stress, depression; (2) MFI Physical Fatigue: physical activity, pain; and (3) MFI Mental Fatigue: stress.

Conclusions

PPS fatigue is multidimensional. Different types of fatigue are determined by different variables. Potentially modifiable factors account for a portion of fatigue in PPS.