bluuebunny/crossref_metadata_2025 huggingface dataset:
Model‐based melt flow virtual sensors for filling process of injection molding
Authors: Lin Yu‐Wei , Cheng J.‐W. John
Published: January 2008

Based on the model‐based virtual sensing approach, previously proposed by the authors, two melt flow virtual sensors are developed. The virtual sensors estimate the melt front position during the filling process by using easily obtained machine variables, specifically, the injection hydraulic pressure and the screw position and nozzle pressure. Both virtual sensors were theoretically analyzed and experimentally evaluated on a commercial injection molding machine. The theoretical analysis provides step‐by‐step design guidelines for the virtual sensors. Performance evaluation with a twin thin‐plate mold validates the feasibility of the proposed model‐based melt‐flow virtual sensors. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Modeling particle inflation from poly(amic acid) powdered precursors. III. Experimental determination of kinetic parameters
Authors: Cano Camilo I. , Clark Meaghan L. , Kyu Thein , Pipes R. Byron
Published: January 2008

Several concurrent phenomena occur during the thermal inflation of poly(amic acid) precursor particles leading to polyimide foams as part of the solid‐state powder foaming process. The precursor experiences bubble growth from within while volatiles desorb and the polymer itself increases its molecular weight and changes its backbone structure. These changes affect the transport properties of the material by modifying significantly the effective glass transition temperature, Tg. By studying the chemical transformations that take place during the inflation process (amidation and imidization reactions), a complete understanding of the material's molecular changes can be obtained and corresponding property changes can be followed. This article is the third of a series where the inflation of precursor materials for polyimide foams has been studied. The two previous articles in the series present numerical models that simulate the inflation process from first principles. In this article, the authors discuss the experimental and analytical methodologies employed to accurately characterize and incorporate the changes in material and transport properties as a function of the glass transition temperature. POLYM. ENG SCI., 2008. © 2008 Society of Plastics Engineers
Miscibility, crystallization behavior and specific intermolecular interactions in thermosetting polymer blends of novolac epoxy resin and polyethylene glycol
Authors: Qin Chen , Shen Jianfeng , Hu Yizhe , Huang Weishi , Ye Mingxin
Published: January 2008

Thermosetting polymer blends of novolac epoxy resin (EPN) and polyethylene glycol (PEG) were studied. The miscibility and crystallization behavior of the blends before curing reaction were investigated by polarized optical microscopy and differential scanning calorimetry (DSC). Overall uncured blend compositions were homogeneous in amorphous state. Single composition‐dependent glass‐transition temperature (Tg) for each blend could be observed, and the experimental Tg's of blends with EPN content ≥40 wt% could be explained well by the Gordon–Taylor equation. Thermal properties of blends cured with 4,4′‐diaminodiphenylmethane were also determined by DSC. The capability of PEG to crystallize in cured blends was different from that in uncured ones because of the topological effect of highly crosslinking structure. On the basis of Fourier transform infrared spectroscopy results, it was judged that there were intermolecular hydrogen‐bonding interactions between EPN and PEG in both cured and uncured blends. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Polylactide‐pine wood flour composites
Authors: Pilla Srikanth , Gong Shaoqin , O'Neill Eric , Rowell Roger M. , Krzysik Andrzej M.
Published: January 2008

Biobased and biodegradable polylactide (PLA)‐pine wood flour (PWF) composites were investigated as a means to reduce the overall material cost and tailor the material properties. The composites were prepared using a kinetic‐mixer and an injection molding machine. The tensile modulus of the PLA‐PWF composites increased with the PWF content whereas the toughness and strain‐at‐break decreased. The tensile strength remained the same irrespective of the PWF content (up to 40%). The storage modulus also increased with the PWF content. Additionally, composites containing PWF treated with silane showed higher storage modulus than those without the silane treatment. The area integration underneath the tan δ peaks decreased with increasing PWF, indicating that the PLA‐PWF composites exhibited more elastic behavior with increasing PWF. The degree of crystallinity of the PLA‐PWF composites increased significantly with the PWF content. Furthermore, the treatment of PWF with silane had a positive effect on its nucleating ability, as treated PLA‐PWF composites showed higher crystallinity compared with their untreated counterparts. The morphology of the fracture surfaces were studied using a scanning electron microscope. Finally, a Halpin‐Tsai analytical model to predict Young's modulus of PLA‐PWF composites was presented to compare the theoretical results with that of experimental results. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Properties of recycled material containing poly(vinyl chloride), polypropylene, and calcium carbonate nanofiller
Authors: Andričić Branka , Kovačić Tonka , Klarić Ivka
Published: January 2008

Even at low content, polypropylene significantly worsens mechanical properties of the recycled PVC composite, i.e. tensile strength at break and elongation at break. But, if small quantities of surface modified nanofiller calcium carbonate is added, an applicable composite that contains 10–30% of waste material can be made. It was determined that nanosized calcium carbonate lowers melting point of polypropylene, perhaps by changing its crystalline form and has no influence on thermooxidative degradation of poly(vinyl chloride). Addition of nanofiller slightly lowers the surface free energy of the composites what is more prone when the low content of polypropylene is present. The recovery of tensile strength and elongation at break occurs and those properties reach the highest value at about 6% of CaCO3. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Thermomechanical behavior of epoxy resins modified with epoxidized vegetable oils
Authors: Jin Fan‐Long , Park Soo‐Jin
Published: January 2008

Biobased epoxy materials were prepared from diglycidyl ether of bisphenol A (DGEBA) and epoxidized vegetable oils (EVOs) (epoxidized soybean oil and epoxidized castor oil) with a thermally latent initiator. The effects of EVO content on the thermomechanical properties of the EVO‐modified DGEBA epoxy resins were investigated using several techniques. Differential scanning calorimetry indicated that the cure reaction of the DGEBA/EVO systems proceeded via two different reaction mechanisms. Single and composition‐dependent glass transition temperature (Tg) mechanisms were observed for the systems after curing. The experimental values of Tg could be explained by the Gordon–Taylor equation [Gordon M and Taylor JS, J Appl Chem 2:493 (1952)]. The thermal stability of the systems decreased as the EVO content increased, due to the lower crosslinking density of the DGEBA/EVO systems. The coefficient of thermal expansion of the systems was found to increase linearly with increasing EVO content. This could be attributed to the fact that the degrees of freedom available for motions of the segments of the macromolecules in the network structure were enhanced by the addition of EVO. Copyright © 2008 Society of Chemical Industry
Two novel oligomers based on fluorene and pyridine: Correlation between the structures and optoelectronic properties
Authors: Jiang Hong‐Ji , Wang Hong‐Yu , Zhu Rui , Wan Jun‐Hua , Liu Feng , Feng Jia‐Chun , Wei Wei , Huang Wei
Published: January 2008

To investigate the fine optoelectronic difference of the target oligomers with or without peripheral fluorene moieties, two dumbbell‐shaped oligomers (F0 and F1) were designed and convergently prepared via Suzuki coupling reaction. The molecular structures of the oligomers were fully characterized by 1H NMR, 13C NMR, and MALDI‐TOF mass spectra, respectively. The absorption, photoluminescent behavior, and energy band gaps of the oligomers were examined through UV–vis, photoluminescent spectra and cyclic voltammetry. The experimental results demonstrate that the absorption and photoluminescent properties are little affected by molecular architecture, while the absolute photoluminescence quantum efficiency of films and energy band gaps derived from cyclic voltammetry in solution are strongly correlated with the molecular frameworks. The observed energy band gaps of oligomers are further validated by the different molecular orbital contours of the HOMO energy levels from theoretical calculations. Preliminary electroluminescent investigations for F1 have also been conducted and discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1548–1558, 2008
Penultimate effect in radical copolymerization of 2‐trifluoromethylacrylates
Authors: Ito Hiroshi , Trinque Brian C. , Kasai Paul , Willson C. Grant
Published: January 2008

Electron‐deficient 2‐trifluoromethylacrylates (TFMA) undergo radical copolymerization with electron‐rich norbornene derivatives, vinyl ethers, and styrene derivatives, which can be described by the penultimate model much better than by the commonly employed terminal model. In an attempt to directly observe the effect of the CF3 group in the penultimate unit on the radical reactivity, we employed the Giese's mercury method. 4,4,4‐Trifluorobutyl and n‐butyl radicals produced from respective alkylmercuric chlorides were competitively reacted with t‐butyl 2‐trifluoromethylacrylate (TBTFMA) and t‐butyl methacrylate (TBMA) and the products analyzed with gas chromatography. While TBTFMA has been found to be about 24times more reactive than TBMA toward the n‐butyl radical, the former is about 12 times more reactive than the latter toward the 4,4,4‐trifluorobutyl radical. Thus, the reactivity of the propagating radical toward TBTFMA in comparison with TBMA is suppressed by a factor of two when the penultimate unit has the CF3 group. We observed a sextet electron spin resonance of the TFMA propagating radical with a coupling constant of ca. 25 gauss between the β‐proton and β‐fluorine. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1559–1565, 2008
Synthesis, characterization, and electroluminescence of PPV copolymers containing electron and hole‐transporting units
Authors: Xun Shidi , Zhou Quanguo , Li Hongchao , Ma Dongge , Wang Lixiang , Jing Xiabin , Wang Fosong
Published: January 2008

Three series of poly(phenylene vinylene) (PPV) derivatives containing hole‐transporting triphenylamine derivatives [N‐(4‐octoxylphenyl)diphenylamine, N,N′‐di(4‐octyloxylphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, and N,N′‐di(4‐octoxylphenyl)‐N,N′‐diphenylbenzidine] (donor) and electron‐transporting oxadiazole unit (2,5‐diphenyl‐1,3,4‐oxadiazole) (acceptor) in the main chain were synthesized by improved Wittig copolymerization. The resulting donor–acceptor (D‐A) polymers are readily soluble in common organic solvents, such as chloroform, dichloroethane, THF, and toluene. The polymers containing oxadiazole group exhibit good thermal stability with 5% weight loss above 400 °C. The intramolecular charge‐transfer was observed in these D‐A polymers. In comparison with corresponding polymers without oxadiazole unit, the single‐layer devices based on the D‐A polymers showed much improved electroluminescent properties, because of the balanced charge injection and transport. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1566–1576, 2008
Dimer effect on fractional polycondensation of poly(p‐oxybenzoyl)
Authors: Kimura Kunio , Shimizu Yasuo , Ichimori Toshimitsu , Kohama Shin‐ichiro , Yamazaki Shinichi , Yamashita Yuhiko
Published: January 2008

Selective preparation of poly(p‐oxybenzoyl) (POB) crystals was examined from the viewpoint of a dimer effect on fractional polycondensation. Four different copolymerization systems were chosen as the combinations ofp‐acetoxybenzoic acid (p‐ABA),m‐acetoxybenzoic acid (m‐ABA), and their dimers. The crystals obtained from the copolymerization of the dimer ofp‐ABA (p‐ABAD) andm‐ABA contained only 3.1 mol % ofm‐oxybenzoyl moiety even at high content ofm‐oxybenzoyl moiety in feed (χf) of 40 mol %.p‐Oxybenzoyl homo‐oligomers were more rapidly formed fromp‐ABAD in the solution than fromp‐ABA, and they were crystallized to form the crystals with segregating co‐oligomers. While co‐oligomers containing morem‐oxybenzoyl moiety were formed in the solution, afterward they were unable to be phase‐separated because of higher miscibility. The further polycondensation proceeded in the precipitated crystal, and finally the POB crystal was selectively formed. Lower polymerization temperature and concentration enhanced the fractionability, and the POB crystals containing less than 1 mol %m‐oxybenzoyl moiety were prepared at χfof 30 mol %, 270 °C, and a concentration of 0.5%. The dimer effect on the fractional polycondensation was clearly observed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1598–1606, 2008
Synthesis and characterization of a series of 2‐aminopyridine nickel(II) complexes and their catalytic properties toward ethylene polymerization
Authors: Huang Zengfang , Song Keming , Liu Fengshou , Long Jieming , Hu Hao , Gao Haiyang , Wu Qing
Published: January 2008

A series of 2‐aminopyridine Ni(II) complexes bearing different substituent groups {(2‐PyCH2NAr)NiBr, Ar = 2,4,6‐trimethylphenyl (3a), 2,6‐dichlorophenyl (3b), 2,6‐dimethylphenyl (3c), 2,6‐diisopropylphenyl (3d), 2,6‐difluorophenyl (3e); (2‐PyCH2NHAr)2NiBr2, Ar = 2,6‐diisopropylphenyl (4a)} have been synthesized and investigated as precatalysts for ethylene polymerization in the presence of methylaluminoxane (MAO). High molecular weight branched polymers as well as short‐chain oligomers were simultaneously produced with these complexes. Enhancing the steric bulk of the ortho‐aryl‐substituents of the catalyst resulted in higher ratio of solid polymer to oligomer and higher molecular weight of the polymer. With ortho‐haloid‐substitution, the catalysts afforded a product with low polymer/oligomer ratio (3b) and even only oligomers (3e) in which C14H28 had the maximum content. Compared with complex 3d containing ionic ligand, complex 4a containing neutral ligand exhibited obviously low catalytic activity for ethylene polymerization. The molecular weight, molecular weight distribution, and microstructure of the resulted polymer were characterized by gel permeation chromatography and 13C NMR spectrogram. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1618–1628, 2008
Living cationic polymerization of 2‐adamantyl vinyl ether
Authors: Hashimoto Tamotsu , Makino Yusuke , Urushisaki Michio , Sakaguchi Toshikazu
Published: January 2008

Living cationic polymerization of 2‐adamantyl vinyl ether (2‐vinyloxytricyclo[3.3.1.1]3,7decane; 2‐AdVE) was achieved with the CH3CH(OiBu)OCOCH3/ethylaluminum sesquichloride/ethyl acetate [CH3CH(OiBu)OCOCH3/Et1.5AlCl1.5/CH3COOEt] initiating system in toluene at 0 °C. The number‐average molecular weights (Mn's) of the obtained poly(2‐AdVE)s increased in direct proportion to monomer conversion and produced the polymers with narrow molecular weight distributions (MWDs) (Mw/Mn = ∼1.1). When a second monomer feed was added to the almost polymerized reaction mixture, the added monomer was completely consumed and the Mn's of the polymers showed a direct increase against conversion of the added monomer. Block and statistical copolymerization of 2‐AdVE with n‐butyl vinyl ether (CH2CHOCH2 CH2CH2CH3; NBVE) were possible via living process based on the same initiating system to give the corresponding copolymers with narrow MWDs. Grass transition temperature (Tg) and thermal decomposition temperature (Td) of the poly(2‐AdVE) (e.g., Mn = 22,000, Mw/Mn = 1.17) were 178 and 323 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1629–1637, 2008
Synthesis of highly conductive EDOT copolymer films via oxidative chemical in situ polymerization
Authors: Chen Jui Hung , Dai Chi‐An , Chiu Wen‐Yen
Published: January 2008

Poly(3,4‐ethylenedioxythiophene)s (PEDOT) represent a class of conjugated polymers that can be potentially used as an electrode material for flexible organic electronics due to their superior conductivity and transparency. In this study, we demonstrate that the conductivity of a PEDOT containing copolymer film can be further enhanced by the oxidative chemical in situ copolymerization of a liquid film spun coated from monomer mixture (3,4‐ethylenedioxythiophene (EDOT) and 3‐thienyl ethoxybutanesulfonate (TEBS)), oxidant (iron(III) p‐toluenesulfonate (Fe(OTs)3)), weak base (imidazole), and solvent (methanol). We investigated that the effect of the processing parameters such as the molar ratios TEBS/EDOT, IM/EDOT, and Fe(OTs)3/EDOT on the surface morphology, optical property, and the conductivity of the resulting copolymer films. These parameters have been optimized to achieve conductivities for the copolymer films as high as 170 S/cm compared with a conductivity of 30 S/cm for the pure PEDOT film synthesized using the same fabrication method. This conductivity enhancement for the copolymer films was found to be resulted from the fact that the addition of TEBS monomer reduces the copolymerization rate, leading to the formation of much more uniform film surface without defects and copolymers of higher molecular weight which increase the conductivity of the resulting copolymer film. The composition of two monomers in the copolymer film is not related to the variation of conductivity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1662–1673, 2008
Sonochemical immobilization of silver nanoparticles on porous polypropylene
Authors: Perkas Nina , Shuster Michael , Amirian Galina , Koltypin Yuri , Gedanken Aharon
Published: January 2008

Silver nanoparticles were immobilized on the surface of polypropylene (PP) porous beads by an ultrasound‐assisted reduction method. The structure and properties of the silver–PP composite were characterized with XRD, TEM, HRSEM, EDX, XPS, and Raman spectroscopy. Water‐soluble polymers such as PEG, PVA, and PVP were used as stabilizing agents for preventing the agglomeration of the silver nanoparticles. With PVP, a homogeneous distribution of silver nanocrystals, 50 nm in size, on the PP surface was achieved. The mechanism proposed for the silver anchoring to the inert polymer accounts for a localized melting of the PP. The beads of the silver PP composite demonstrated good stability and high antibacterial activity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1719–1729, 2008
The proliferative effect of estradiol on human prostate stromal cells is mediated through activation of ERK
Authors: Zhang Zhisong , Duan Lei , Du Xiaoling , Ma Hongshun , Park Irwin , Lee Chung , Zhang Ju , Shi Jiandang
Published: January 2008

Background

Estrogen is involved in the development and progression of benign prostatic hyperplasia (BPH). It can stimulate proliferation of prostate stromal cells (PrSCs). However, the exact mechanism remains unclear.

Methods

We used the primary cultured human PrSCs and a prostate stromal cell line, WPMY‐1, to examine the signaling pathways involved in estrogen‐mediated proliferation of PrSCs. Cells were treated with 17β‐estradiol (E2) or BSA‐E2. Cell proliferation was assessed by the MTT assay and by cell counting. Western blot analysis was used to determine the status of activation of ERK1/2.

Results

Results indicated that both E2 and BSA‐E2 stimulated proliferation of primary PrSCs and WPMY‐1 cells. ERK was rapidly activated by E2 and BSA‐E2. PD98059, which is a selective ERK inhibitor, significantly inhibited estrogen‐induced cell proliferation. PrSCs expressed estrogen receptor α (ERα) and GPR30 but not ERβ. Small hairpin RNA (shRNA) to ERα, but not to GPR30, blocked estrogen‐mediated ERK activation and cell proliferation.

Conclusions

The results indicated that estrogen could activate ERK pathway through the non‐genomic ERα pathway, leading to proliferation of PrSCs. Prostate 68: 508–516, 2008. © 2008 Wiley‐Liss, Inc.
The metabolites citrate, myo‐inositol, and spermine are potential age‐independent markers of prostate cancer in human expressed prostatic secretions
Authors: Serkova Natalie J. , Gamito Eduard J. , Jones Richard H. , O'Donnell Colin , Brown Jaimi L. , Green Spencer , Sullivan Holly , Hedlund Tammy , Crawford E. David
Published: January 2008

Objectives

Due to specific physiological functions, prostatic tissues and fluids have unique metabolic profiles. In this study, proton nuclear magnetic resonance spectroscopy (1H‐NMRS) is used to assess potential metabolic markers of prostate cancer (PCa) in human expressed prostatic secretions (EPS).

Methods

Metabolic profiles of EPS from 52 men with PCa and from 26 healthy controls were analyzed using quantitative 1H‐NMRS. The metabolites quantified included citrate, spermine, myo‐inositol, lactate, alanine, phosphocholine, glutamine, acetate, and hydroxybutyrate. Logistic regression (LR) was used to model the risk of PCa based on metabolite concentrations while adjusting for age.

Results

The average age of the EPS donors with PCa was 58.0 ± 7.0 years and 52.2 ± 12.1 for the healthy donors. The median Gleason score for the men with PCa was 7 (range 5–9). The LR models indicated that the absolute concentrations of citrate, myo‐inositol, and spermine were highly predictive of PCa and inversely related to the risk of PCa. The areas under the receiver operating characteristic curves (AUROC) for citrate, myo‐inositol and spermine were 0.89, 0.87, and 0.79, respectively. At 90% sensitivity, these metabolites had specificities of 74%, 51%, and 34%, respectively. The LR analysis indicated that absolute levels of these three metabolites were independent of age.

Conclusions

The results indicate that citrate, myo‐inositol and spermine are potentially important markers of PCa in human EPS. Further, the absolute concentrations of these metabolites in EPS appear to be independent of age, increasing the potential utility of these markers due to elimination of age as a confounding variable. Prostate 68: 620–628, 2008. © 2008 Wiley‐Liss, Inc.
Influence of isomorphous substitution on NO and N2O thermochemistry on Au/ZSM‐5 catalyst
Authors: Sierraalta Anibal , Alejos Paola , Ehrmann Elena
Published: January 2008

Density functional calculations have been carried out to investigate the effects of the Al isomorphic substitution by B and Ga on the geometries, adsorption energies and vibrational frequencies of NO and N2O on a model for Au(I) ion‐exchanged ZSM‐5 catalysts. It is shown for first time, that the adsorption of NO, two NO, and N2O are thermodynamically more favored on Au/[B]ZSM‐5 than on Au/[Al]ZSM‐5 or Au/[Ga]ZSM‐5. The isomorphous substitution in ZSM‐5 affects the electronic properties of Au(I), reducing the band gap HOMO‐LUMO, favoring the NO adsorption. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Comparison of two test methods for evaluation of forming tool materials
Authors: Hanson Magnus , Gåård Anders , Krakhmalev Pavel , Hogmark Sture , Bergström Jens
Published: January 2008

Two test methods often used to simulate the tribological performance of forming tool materials are compared in this investigation through an evaluation of the friction and wear properties of four tool steels in dry sliding. One test (slider‐on‐flat‐surface (SOFS)) utilises a vertical disc sliding on a horizontal flat test surface, and the other (load scanner (LS) tests) utilises two crossed cylindrical rods. The test conditions were selected as equal as possible for the two tests, and the following conclusions are made.

Somewhat unexpectedly, the friction and wear results differed substantially between the two tests. The SOFS test showed a better potential to evaluate wear resistance since one test sample is in continuous contact with the other. The LS test can generate higher contact pressures since the two rods contact each other in an unworn condition throughout the whole test stroke.

LS indicate that two hard and smooth tool steels tested against each other generally give low friction and good galling resistance. The two hard couples tested sustained the highest loads without any detectable surface damage. For the same combinations of hard steels, SOFS gave a higher friction due to the wear of the disc. The carbides in the disc material resist wear better than the matrix and will consequently wear the disc by abrasion, which adds to the friction.

The above conclusions are drawn from a rather limited examination using only one set of test parameters. In fact, the two tests are both very flexible as to the way they can be used, and they both have advantages and limitations in tribological studies. They should rather be considered complementary than competitive. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of cysteine dosage on erythrocyte glutathione synthesis rate in a patient with cystathionine beta synthase deficiency
Authors: van der Crabben S. N. , Wijburg F. A. , Ackermans M. T. , Sauerwein H. P.
Published: January 2008

Cystathionine β‐synthase (CBS)‐deficient patients develop premature arteriosclerosis and thrombosis leading to a high risk of a vascular event before the age of 30 years. In CBS deficiency the transsulfuration pathway is impaired, leading to markedly elevated levels of homocysteine and methionine, and severely decreased levels of cystathionine and cysteine. Through autooxidation these elevated levels of homocysteine might induce excessive production of reactive oxygen species (ROS). ROS are involved in endothelial damage and are neutralized by antioxidants. In humans the main antioxidant is glutathione (GSH). Its production mainly depends on the amount of available cysteine. Since cysteine levels in CBS deficiency are decreased, GSH production is presumed to be low. Accordingly, all CBS‐deficient patients receive cysteine supplements, which supposedly stimulate GSH synthesis. However, data on the effect of cysteine dosage on GSH synthesis in CBS‐deficient patients are lacking. Therefore, in a CBS‐deficient pyridoxine non‐responsive female patient, concentration and fractional synthesis rate (FSR) of erythrocyte GSH were measured by infusion of l‐[3,3‐2H2]cysteine tracer during prolonged cysteine supplementation with 88 and 40 mg/kg per day. Erythrocyte GSH concentration and its FSR at cysteine supplementation with 88 versus 40 mg/kg per day were 1.25 versus 1.30 mmol/L and 230 versus 254% per day, respectively. These data suggest that in a CBS‐deficient patient exogenous supply of 40 mg cysteine/kg per day is sufficient to maintain GSH synthesis in erythrocytes. Further studies in larger patient groups should be initiated to measure the effects on GSH metabolism to further elucidate the correct dose of cysteine supplements in CBS‐deficient patients.
Methylmalonate inhibits succinate‐supported oxygen consumption by interfering with mitochondrial succinate uptake
Authors: Mirandola S. R. , Melo D. R. , Schuck P. F. , Ferreira G. C. , Wajner M. , Castilho R. F.
Published: January 2008

The effect of methylmalonate (MMA) on mitochondrial succinate oxidation has received great attention since it could present an important role in energy metabolism impairment in methylmalonic acidaemia. In the present work, we show that while millimolar concentrations of MMA inhibit succinate‐supported oxygen consumption by isolated rat brain or muscle mitochondria, there is no effect when either a pool of NADH‐linked substrates or N,N,N′,N′‐tetramethyl‐p‐phenylendiamine (TMPD)/ascorbate were used as electron donors. Interestingly, the inhibitory effect of MMA, but not of malonate, on succinate‐supported brain mitochondrial oxygen consumption was minimized when nonselective permeabilization of mitochondrial membranes was induced by alamethicin. In addition, only a slight inhibitory effect of MMA was observed on succinate‐supported oxygen consumption by inside‐out submitochondrial particles. In agreement with these observations, brain mitochondrial swelling experiments indicate that MMA is an important inhibitor of succinate transport by the dicarboxylate carrier. Under our experimental conditions, there was no evidence of malonate production in MMA‐treated mitochondria. We conclude that MMA inhibits succinate‐supported mitochondrial oxygen consumption by interfering with the uptake of this substrate. Although succinate generated outside the mitochondria is probably not a sig‐nificant contributor to mitochondrial energy generation, the physiopathological implications of MMA‐induced inhibition of substrate transport by the mitochondrial dicarboxylate carrier are discussed.
Re‐ or displacement of invariant residues in the C‐terminal half of the catalytic domain strongly affects catalysis by glucosyltransferase R
Authors: Wittrock Sabine , Swistowska Anna Maria , Collisi Wera , Hofmann Birgit , Hecht Hans-Jürgen , Hofer Bernd
Published: January 2008

It is shown that exchanges of single invariant amino acids in two C‐terminal catalytic domain segments of the glucosyltransferase R (GtfR) strongly affect its catalytic properties. Drastic decreases of activity through re‐ or displacements of Tyr965 demonstrate a crucial role of this residue. Similarly, exchanges of amino acids Asp1004, Val1006, and Tyr1011 profoundly influenced catalytic parameters. These results are interpreted on the basis of a homology model of the catalytic domain. They are consistent with the view that Tyr965 is a constituent of the substrate‐binding pocket and directly contacts the sucrose molecule, whereas the other critical residues contribute to the required positioning of Tyr965 and other active site residues.
Oligomeric β‐amyloid(1‐42) induces the expression of Alzheimer disease‐relevant proteins in cholinergic SN56.B5.G4 cells as revealed by proteomic analysis
Authors: Joerchel Sabrina , Raap Maik , Bigl Marina , Eschrich Klaus , Schliebs Reinhard
Published: January 2008

Alzheimer's disease (AD) is characterized by cholinergic dysfunction and progressive basal forebrain cell loss which has been hypothesized to be associated with extensive accumulation of β‐amyloid (Aβ). To reveal whether oligomeric Aβ displays a particular toxicity for cholinergic neurons, the cholinergic cell line SN56.B5.G4 (SN56) was used as a model. Recently performed microarray analyses demonstrated that genes affected by exposure of SN56 cells with 50 μM oligomeric Aβ(1‐42) for 24 h were involved in protein modification and degradation [Heinitz, K., Beck, M., Schliebs, R., Perez‐Polo, J.R., 2006. Toxicity mediated by soluble oligomers of beta‐amyloid(1‐42) on cholinergic SN56.B5.G4 cells. J. Neurochem. 98, 1930–1945]. Using a proteomic approach, we compared the levels of proteins and specially of phosphorylated proteins in cytosolic fractions of cell lysates from cholinergic SN56 cells exposed to 50 μM Aβ(1‐42) for 24 h to those in control incubations. We show here that the levels of calreticulin, and mitogen‐activated protein kinase (MAPK) kinase 6c were up‐regulated in cholinergic SN56 cells exposed to Aβ(1‐42), while γ‐actin appeared down‐regulated. Aβ(1‐42) exposure of cholinergic SN56 cells led to decreased phosphorylation of phosphoproteins, such as the Rho GDP dissociation inhibitor, the ubiquitin carboxyl terminal hydrolase‐1, and the tubulin α‐chain isotype Mα6, as compared to untreated control lysates. The proteins identified have also been reported to be affected in brains of AD patients, suggesting a potential role of Aβ in influencing the integrity and functioning of the proteome in AD.
PCR detection of excision suggests mobility of the medaka fishTol1transposable element in the frogXenopus laevis
Authors: HIKOSAKA AKIRA , KOGA AKIHIKO
Published: January 2008

Tol1is a DNA-based transposable element identified in the medaka fishOryzias latipesand a member of thehAT(hobo/Activator/Tam3) transposable element family. Its mobility has already been demonstrated in the human and mouse, in addition to its original host species. This element is thus expected to be useful in a wide range of vertebrates as a genomic manipulation tool. Herein, we show that theTol1element can undergo excision in the African clawed frogXenopus laevis, a major model organism for vertebrate genetics and developmental biology. An indicator plasmid carrying aTol1element was injected into 2- or 4-cell-stage embryos together with either a helper plasmid coding for the full-lengthTol1transposase or a modified helper plasmid yielding a truncated protein, and recovered from tailbud-stage embryos. Deletion of theTol1region of the indicator plasmid was observed in the experiment with the full-length transposase, and not in the other case. The deletion was associated with various footprint sequences at breakpoints, as frequently observed with many DNA-based transposable elements. These results indicate that theTol1element was excised from the indicator plasmid by catalysis of the transposase, and suggest that theTol1element is mobile in this frog species.
Efficient, incremental coverage of space with a continuous curve
Authors: Ramamoorthy Subramanian , Rajagopal Ram , Wenzel Lothar
Published: January 2008

This paper is concerned with algorithmic techniques for the incremental generation of continuous curves that can efficiently cover an abstract surface. We introduce the notion of low-discrepancy curves as an extension of the notion of low-discrepancy sequences—such that sufficiently smooth curves with low-discrepancy properties can be defined and generated. We then devise a procedure for lifting these curves, that efficiently cover the unit cube, to abstract surfaces, such as nonlinear manifolds. We present algorithms that yield suitable fair mappings between the unit cube and the abstract surface. We demonstrate the application of these ideas using some concrete examples of interest in robotics.
Large-Deviation Approximations for General Occupancy Models
Authors: ZHANG JIM X. , DUPUIS PAUL
Published: January 2008

We obtain large-deviation approximations for the empirical distribution for a general family of occupancy problems. In the general setting, balls are allowed to fall in a given urn depending on the urn's contents prior to the throw. We discuss a parametric family of statistical models that includes Maxwell–Boltzmann, Bose–Einstein and Fermi–Dirac statistics as special cases. A process-level large-deviation analysis is conducted and the rate function for the original problem is then characterized, via the contraction principle, by the solution to a calculus of variations problem. The solution to this variational problem is shown to coincide with that of a simple finite-dimensional minimization problem. As a consequence, the large-deviation approximations and related qualitative information are available in more-or-less explicit form.
THE FISCAL THEORY OF THE PRICE LEVEL PUZZLE: A NON-RICARDIAN VIEW
Authors: BÉNASSY JEAN-PASCAL
Published: January 2008

The fiscal theory of the price level says that the price level can be made determinate if the government uses fiscal policies such that government liabilities explode unless the price in the first period is at the “right” level. The policy implications are disturbing, as they call for rather adventurous fiscal policies. We show that these disturbing policy implications are specific to the “Ricardian” models that have been used to develop the theory. By moving to non-Ricardian models, we see that price determinacy is consistent with reasonable fiscal policies.
Torture of terrorists? Use of torture in a “war against terrorism”: justifications, methods and effects: the case of France in Algeria, 1954–1962
Authors: Branche Raphaëlle
Published: January 2008

During its war against the armed nationalist movement fighting for Algerian independence (1954–62), France made extensive use of torture, for which the main justification given was the terrorism employed by the National Liberation Front, even though such terrorist violence was neither the nationalists' main form of action nor the French army's true target. Research into the methods used and the aims pursued challenges that justification, shedding light on the way in which torture really operates in a war of this kind, even though the Algerian War has been presented as a model for many subsequent conflict situations.
“In truth the leitmotiv”: the prohibition of torture and other forms of ill-treatment in international humanitarian law
Authors: Droege Cordula
Published: January 2008

The principle of humane treatment, as Jean Pictet wrote in 1958, is in truth the leitmotiv of the four Geneva Conventions of 1949. Article 3 common to these Conventions and other provisions of International Humanitarian Law embody this absolute and minimum rule by prohibiting torture, cruel or inhuman treatment and outrages upon personal dignity. These notions can be interpreted in meaningful and practical ways through the existing instruments and jurisprudence on the prohibition of ill-treatment. Their assessment must take into account the need to respect the human being in all his or her physical, mental and moral integrity, mindful of all the circumstances of the case.
Black letter abuse: the US legal response to torture since 9/11
Authors: Ross James
Published: January 2008

The use of torture by the US armed forces and the CIA was not limited to “a few bad apples” at Abu Ghraib but encompassed a broader range of practices, including rendition to third countries and secret “black sites”, that the US administration deemed permissible under US and international law. This article explores the various legal avenues pursued by the administration to justify and maintain its coercive interrogation programme, and the response by Congress and the courts. Much of the public debate concerned defining and redefining torture and cruel, inhuman and degrading treatment. While US laws defining torture have moved closer to international standards, they have also effectively shut out those seeking redress for mistreatment from bringing their cases before the courts and protect those responsible from prosecution.
Die deutsche Version des “Psychopathic Personality Inventory“ (PPI)
Authors: Martín Beatriz Arias , Halder-Sinn Petra , Funsch Karin , Rindfleisch Hanna
Published: January 2008

Zusammenfassung. Psychopathie ist der relevanteste Prädiktor für die Prognose delinquenten Verhaltens. Bis zum heutigen Zeitpunkt wird Psychopathie üblicherweise mittels der PCL-R ( Hare, 1990/91 ), welche sehr zeit- und kostenaufwendig ist, erfasst. Das Psychopathic Personality Inventory ( Lilienfeld & Andrews, 1996 ) ist ein Selbstrating-Verfahren zur Erfassung psychopathischer Persönlichkeitseigenschaften, welches aus 10 Subskalen mit insgesamt 187 Items (8 Inhaltsskalen mit insgesamt 163 Items und 2 Validitätsskalen mit 24 Items) besteht. Die Deutsche Version wurde einer Stichprobe von insgesamt N = 290 Probanden (N = 187 Probanden einer Stichprobe der Normalbevölkerung und N = 103 Studenten) vorgelegt. Die psychometrischen Eigenschaften (Reliabilität und Validität) zeigen sehr zufrieden stellende Ergebnisse mit einer internen Konsistenz von α = .91 und einer Test-Retest-Reliabilität (nach Pearson; Zeitintervall: 12 Wochen) für den PPI-Gesamtscore von r = .96. Geschlechtsunterschiede für den Gesamtscore sowie für die Skalenscores wurden in erwarteter Richtung gefunden. Abschließend konnte die konvergente sowie diskriminante Validität mittels NEO-FFI und dem Interaktions-Angst-Fragebogen IAF bestätigt werden. Obwohl die faktorielle Struktur (überprüft mittels CFA und EFA) Abweichungen von der Originalversion aufzeigt, kann die deutsche Version des PPI als ein hoch reliables und valides Instrument angesehen werden.
Manche mögen’s heiß
Authors: Appel Markus
Published: January 2008

Zusammenfassung. Komplementär zu need for cognition und anderen sozialpsychologischen needs beschreiben Maio und Esses (2001) situationsübergreifende Unterschiede in der Tendenz, Situationen und Aktivitäten aufzusuchen (bzw. zu vermeiden), die zu intensiven Emotionen bei sich oder anderen führen (need for affect). Eine diesbezügliche Skala zur Selbstbeschreibung beinhaltet die Subskalen Annäherung und Vermeidung. In zwei Studien mit N = 403 und N = 251 TeilnehmerInnen konnte eine gute Reliabilität und Konstruktvalidität einer deutschsprachigen Version festgestellt werden. Das Emotionsmotiv bzw. die Subskala Annäherung stehen erwartetermaßen in Zusammenhang mit der Rezeption von Liebesfilmen sowie mit dem Wunsch, affektiv negativ beschriebene Spielfilme anzusehen (experimentelles Design mit Messwiederholung, nur Frauen). Eine Passung von Emotionsmotiv und emotionalem Anregungsgehalt der beruflichen Tätigkeit prädiziert ferner das Job Involvement im Beruf.
Confirmatory Factor Analysis of the Strengths and Difficulties Questionnaire in a Community Sample of French-Speaking Adolescents
Authors: d'Acremont Mathieu , Van der Linden Martial
Published: January 2008

Abstract. The Strengths and Difficulties Questionnaire (SDQ) assesses adaptive and problematic behavior in children and adolescents ( Goodman, 1997 ). The aim of this study was to test the construct validity of a French translation of the scale. Teachers completed the SDQ for their pupils (279 girls and 278 boys, 13-18 years). Confirmatory factor analysis (CFA) of the SDQ supported the original distinction between Conduct problems, Hyperactivity/Inattention, Peer problems, Emotional symptoms, and Prosocial behavior. Multigroup CFA revealed invariance of factor measurement across gender. In addition, boys had higher factor scores for Conduct problems, Hyperactivity/Inattention, and Peer problems whereas girls were more Prosocial. The internal reliability of the subscales ranges from acceptable to very good. These results indicate that the French version of the SDQ has a reliable factor organization among adolescent boys and girls.
The Personal Structure of Personal Need for Structure
Authors: Meiser Thorsten , Machunsky Maya
Published: January 2008

Abstract. This study investigated the responses of N = 1,789 participants to a set of 12 Likert-type items for the assessment of personal need for structure (PNS). Mixture-distribution Rasch models were used to analyze the homogeneity of the response format across items and the homogeneity of the item parameters and category parameters across persons. Model selection yielded a two-class rating scale model as the favorite model. This model contains the assumptions that the Likert response scale is used in a constant way for all items but that the item or category parameters differ between two latent subpopulations. The parameter estimates revealed large differences in the threshold parameters for the response categories between the two subpopulations. While the larger subpopulation showed a tendency to avoid extreme response categories, the smaller subpopulation used the whole range of the response scale. The different response styles identified by the mixture-distribution Rasch analysis were validated by significantly higher Extraversion scores for participants in the smaller subpopulation that showed more extreme and impulsive rating behavior. The results confirmed that PNS reflects quantitative interindividual differences, and they also showed that the total score of the 12 PNS items forms a combination of the latent PNS trait and response style.
Confirmatory Factor Analysis of the Adolescent Self-Report Strengths and Difficulties Questionnaire
Authors: Percy Andrew , McCrystal Patrick , Higgins Kathryn
Published: January 2008

Abstract. The Strengths and Difficulties Questionnaire (SDQ) is a widely used 25-item screening test for emotional and behavioral problems in children and adolescents. This study attempted to critically examine the factor structure of the adolescent self-report version. As part of an ongoing longitudinal cohort study, a total of 3,753 pupils completed the SDQ when aged 12. Both three- and five-factor exploratory factor analysis models were estimated. A number of deviations from the hypothesized SDQ structure were observed, including a lack of unidimensionality within particular subscales, cross-loadings, and items failing to load on any factor. Model fit of the confirmatory factor analysis model was modest, providing limited support for the hypothesized five-component structure. The analyses suggested a number of weaknesses within the component structure of the self-report SDQ, particularly in relation to the reverse-coded items.
Validation of Muñoz's Mood Screener in a Nonclinical Spanish Population
Authors: Vázquez Fernando L. , Muñoz Ricardo F. , Blanco Vanessa , López María
Published: January 2008

Abstract. This study evaluates the utility of Muñoz's Mood Screener for detection of major depressive episodes in a nonclinical Spanish population. The Mood Screener was administered by face-to-face interview to 554 subjects (65.9% women; age 18-34 years) who were recruited by stratified random sampling from a population of 27,587 university students. Thereafter, two expert clinicians who were blind to the Mood Screener results independently administered a clinical interview (SCID-CV) as an aid in evaluating the subjects for the same disorder. κ for agreement between the clinicians' consensus diagnosis and the Mood Screener was 0.758, and with the clinicians' diagnosis as reference the Mood Screener had a sensitivity of 0.969, a specificity of 0.967, positive and negative predictive values of 0.646 and 0.998, respectively, and positive and negative likelihood ratios of 29.75 and 0.032, respectively. These results support the interviewer-administered Mood Screener as a valid instrument for screening for major depressive episodes in the target population.
Consequences of Misspecifying the Error Covariance Structure in Linear Mixed Models for Longitudinal Data
Authors: Vallejo Guillermo , Ato Manuel , Valdés Tamara
Published: January 2008

Abstract. Repeated measures and longitudinal data are frequently analyzed using a linear mixed model. According to this approach, rather than presuming a certain type of covariance structure analysts choose the model that best describes their data prior to carrying out inferences of interest. Because it is not possible to know the underlying covariance structure in advance, researchers often use fit criteria to select from possible covariance structures. SAS Institute's (2004) Proc Mixed program, allows users to model the correct covariance structure by comparing Akaike's Information Criterion (AIC), Hurvich and Tsai's Criterion (AICC), Schwarz's Bayesian Criterion (BIC), Bozdogan's Criterion (CAIC), and Hannan and Quinn's Criterion (HQIC). Monte Carlo methods are used to examine performance of these criteria. The program also investigated the effects of misspecification on properties of the inferences. The results of the simulation show that neither criterion always lead to correct selection of model and that misspecification has negative consequences on estimates of standard errors of linear combinations and tests. When data were generated from symmetric distributions, the best AIC model generally provided robust Type I error control for tests of fixed effects. However, when data were generated from distributions with moderate or severe skewness, neither criterion provided valid tests.