bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses, Properties, and Potential Applications of Multicomponent Magnetic Nanoparticles
Authors: Zeng Hao , Sun Shouheng
Published: February 2008

Multicomponent hybrid nanostructures that contain two or more nanometer‐scale components have attracted much attention recently owing to the synergistic properties induced by interactions between these different nanometer‐scale objects. Herein, we give an overview of the efforts to synthesize multicomponent nanoparticles with at least one component being magnetic, and focus on our recent developments. The syntheses are based on heterogeneous nucleation and growth of a second and third component onto seed nanoparticles. These multicomponent nanoparticles show interesting magnetic, magneto‐optical, plasmonic, and semiconducting properties that can be modulated by interfacial interactions between different nanocomponents. This opens up a new avenue to advanced multifunctional nanomaterials for device concepts and applications.
Population‐based research on occupational and environmental factors for leukemia and non‐Hodgkin's lymphoma: The Northern Germany Leukemia and Lymphoma Study (NLL)
Authors: Hoffmann W. , Terschueren C. , Heimpel H. , Feller A. , Butte W. , Hostrup O. , Richardson D. , Greiser E.
Published: February 2008

Background

The Northern Germany Leukemia and Lymphoma Study (NLL) is a population‐based study designed to provide a quantitative basis for investigations into occupational and environmental risk factors for leukemia and lymphoma.

Methods

All incident cases of leukemia and lymphoma diagnosed between 1/1/1986 and 12/31/1998 in six counties in Northern Germany were actively ascertained. Controls were selected from population registries. Use of pesticides, sources of food supply, time spent at home and work, medical and family history were assessed via face‐to‐face interview. This self‐reported information was used in conjunction with direct environmental measurements of pesticides in household dust and electromagnetic fields (EMFs). In addition, geographical information system (GIS) data were used to derive estimates of environmental exposure to pesticides, EMFs associated with transmission lines, and ionizing radiation from routine nuclear power reactor operations. Occupational exposure assessment was based on lifetime work history. For each job, information on branch of industry, company, job description, and duration of employment were ascertained.

Results

Fourteen hundred thirty cases and 3041 controls were recruited. Lifetime residential and workplace histories totaled 49,628 addresses. Occupational exposure to pesticides was reported by 15% of the male participants (women: 16%). Four percent of the men (women: 8%) were occupationally exposed to ionizing radiation for ≥1 year over their lifetime. Sixty four percent of the participants had lived in the vicinity (20 km) of a nuclear power plant in operation.

Conclusions

The NLL illustrates the successful application of innovative methods to simultaneously assess occupational and environmental risk factors for leukemia and lymphoma including radiological hazards, pesticides, and EMFs. Am. J. Ind. Med. 51:246–257, 2008. © 2008 Wiley‐Liss, Inc.
A new autosomal recessive syndrome of ocular colobomas, ichthyosis, brain malformations and endocrine abnormalities in an inbred Emirati family
Authors: Al‐Gazali L. , Hertecant J. , Algawi K. , El Teraifi H. , Dattani M.
Published: February 2008

We report on an inbred Emirati family of Baluchi origin with ocular colobomas, ichthyosis, and endocrine abnormalities associated with midline brain malformations and mental retardation. All affected children had ocular colobomas, developmental delay and midline brain malformations. Hypoplastic pituitary gland was present in all three investigated children. Ichthyosiform dermatitis appeared in infancy in all surviving children. Other variable features include congenital heart defects, hypertrichosis and dark skin involving the dorsum of hands and feet associated with mild degree of palmo‐plantar keratoderma. Some of the features in this family overlap the CHIME (Coloboma of the eye, Heart defect, Ichthyosiform dermatosis, Mental retardation, and Ear defect) syndrome. However, several features described in CHIME syndrome were not present in these children. These include deafness, seizures, oligodontia, and hair abnormalities. Some of the features in these children also overlap with septo‐optic dysplasia (SOD) but optic nerve hypoplasia, mandatory for the diagnosis of SOD, was present in one child only. We suggest that these children have a new autosomal recessive syndrome of ocular colobomas and ichthyosis. © 2008 Wiley‐Liss, Inc.
Genetic analyses of Roundabout (ROBO) axon guidance receptors in autism
Authors: Anitha A. , Nakamura Kazuhiko , Yamada Kazuo , Suda Shiro , Thanseem Ismail , Tsujii Masatsugu , Iwayama Yoshimi , Hattori Eiji , Toyota Tomoko , Miyachi Taishi , Iwata Yasuhide , Suzuki Katsuaki , Matsuzaki Hideo , Kawai Masayoshi , Sekine Yoshimoto , Tsuchiya Kenji , Sugihara Gen‐ichi , Ouchi Yasuomi , Sugiyama Toshiro , Koizumi Keita , Higashida Haruhiro , Takei Nori , Yoshikawa Takeo , Mori Norio
Published: February 2008

Autism is a pervasive developmental disorder diagnosed in early childhood. Abnormalities of serotonergic neurotransmission have been reported in autism. Serotonin transporter (SERT) modulates serotonin levels, and is a major therapeutic target in autism. Factors that regulate SERT expression might be implicated in the pathophysiology of autism. One candidate SERT regulatory protein is the roundabout axon guidance molecule, ROBO. SerT expression in Drosophila is regulated by robo; it plays a vital role in mammalian neurodevelopment also. Here, we examined the associations of ROBO3 and ROBO4 with autism, in a trio association study using DNA from 252 families recruited to AGRE. Four SNPs of ROBO3 (rs3923890, P = 0.023; rs7925879, P = 0.017; rs4606490, P = 0.033; and rs3802905, P = 0.049) and a single SNP of ROBO4 (rs6590109, P = 0.009) showed associations with autism; the A/A genotype of rs3923890 showed lower ADI‐R_A scores, which reflect social interaction. Significant haplotype associations were also observed for ROBO3 and ROBO4. We further compared the mRNA expressions of ROBO1, ROBO2, ROBO3, and ROBO4 in the lymphocytes of 19 drug‐naïve autistic patients and 20 age‐ and sex‐matched controls. Expressions of ROBO1 (P = 0.018) and ROBO2 (P = 0.023) were significantly reduced in the autistic group; the possibility of using the altered expressions of ROBO as peripheral markers for autism, may be explored. In conclusion, we suggest a possible role of ROBO in the pathogenesis of autism. Abnormalities of ROBO may lead to autism either by interfering with serotonergic system, or by disrupting neurodevelopment. To the best of our knowledge, this is the first report relating ROBO with autism. © 2008 Wiley‐Liss, Inc.
DISC1 mRNA expression is not influenced by common Cis‐acting regulatory polymorphisms or imprinting
Authors: Hayesmoore J.B.G. , Bray N.J. , Owen M.J. , O'Donovan M.C.
Published: February 2008

The hypothesis that genetic variation in Disrupted in Schizophrenia 1 (DISC1) influences risk of schizophrenia and other major psychiatric disorders is supported by a growing body of genetic association data and plausible functional biology. Risk of psychiatric disorder is not attributable to non‐synonymous changes that alter the protein coding sequence of DISC1, although certain such variants possibly contribute to risk haplotypes. Thus, it is widely hypothesized that the risk variants at DISC1 influence its expression. As a complicating factor, it has also been recently proposed that DISC1 is subject to imprinting, a hypothesis that would profoundly influence the interpretation of current genetic studies. We have tested these two main hypotheses using allelic expression analysis. Of 148 human brain mRNA samples, 65 were informative for analysis. However, only a single sample showed evidence for unequal expression of paternal and maternal transcripts. Analysis of the proximal promoter region in that subject revealed the presence of a previously unknown duplication of the 22 nucleotides −168 to −147 relative to the transcription start site. However, the altered expression in that subject did not appear to be explained by this insertion. Our data robustly demonstrate that DISC1 is not imprinted in the adult human brain, and strongly suggest that reports of genetic association between DISC1 and psychiatric disorder are not explicable by sequence changes that alter mRNA abundance. © 2008 Wiley‐Liss, Inc.
Catechol‐O‐methyltransferase (COMT) gene variants: Possible association of the Val158Met variant with opiate addiction in hispanic women
Authors: Oosterhuis Bronson E. , LaForge K. Steven , Proudnikov Dmitri , Ho Ann , Nielsen David A. , Gianotti Robert , Barral Sandra , Gordon Derek , Leal Suzanne M. , Ott Jurg , Kreek Mary Jeanne
Published: February 2008

Catechol‐O‐methyltransferase (COMT) catalyzes the breakdown of catechol neurotransmitters, including dopamine, which plays a prominent role in drug reward. A common single nucleotide polymorphism (SNP), G472A, codes for a Val158Met substitution and results in a fourfold down regulation of enzyme activity. We sequenced exon IV ofCOMTgene in search for novel polymorphisms and then genotyped four out of five identified by direct sequencing, using TaqMan assay on 266 opioid‐dependent and 173 control subjects. Genotype frequencies of the G472A SNP varied significantly (P = 0.029) among the three main ethnic/cultural groups (Caucasians, Hispanics, and African Americans). Using a genotype test, we found a trend to point‐wise association (P = 0.053) of the G472A SNP in Hispanic subjects with opiate addiction. Further analysis of G472A genotypes in Hispanic subjects with data stratified by gender identified a point‐wise significant (P = 0.049) association of G/A and A/A genotypes with opiate addiction in women, but not men. These point‐wise significant results are not significant experiment‐wise (atP < 0.05) after correction for multiple testing. No significant association was found with haplotypes of the three most common SNPs. Linkage disequilibrium patterns were similar for the three ethnic/cultural groups. © 2008 Wiley‐Liss, Inc.
Elektrostatische Aufladung durch Separierung von Ionen an Grenzflächen: Kontaktelektrisierung von ionischen Elektreten
Authors: McCarty Logan S. , Whitesides George M.
Published: February 2008

Gegenstand dieses Aufsatz sind ionische Elektrete: ihre Herstellung, ihr Bildungsmechanismus, Methoden zu ihrer Charakterisierung und ihre Anwendungen. Ein Elektret ist ein Material, das an seiner Oberfläche ein permanentes makroskopisches elektrisches Feld aufweist; dieses Feld kann aus einer Nettoausrichtung von polaren Gruppen im Material oder aus einer makroskopischen elektrostatischen Nettoladung auf dem Material resultieren. Ein ionisches Elektret ist ein Material, das aufgrund einer unterschiedlichen Zahl von kationischen und anionischen Ladungen eine elektrostatische Nettoladung aufbaut. Jedes Material, das Ionen auf seiner Oberfläche trägt oder verfügbare Ionen in der Volumenphase enthält, ist ein potenzielles ionisches Elektret. Wird ein derartiges Material mit einem anderen Material in Kontakt gebracht, können zwischen ihnen Ionen übertragen werden. Falls Anionen und Kationen unterschiedliche Transferneigungen haben, kann dies dazu führen, dass zwischen den beiden Materialien eine Nettoladung übertragen wird. Ionische Elektrete, deren Bildung auf diesem Ionentransfermechanismus basiert, sind das Thema dieses Aufsatzes, der sowohl experimentelle Nachweise als auch theoretische Modelle diskutiert; außerdem wird eine noch unbewiesene Hypothese vorgeschlagen, wonach dieser Ionentransfermechanismus auch die allgegenwärtige Kontaktelektrisierung (“statische Elektrizität”) von Materialien, z. B. organischen Polymeren, erklären könnte, die nicht explizit Ionen auf ihrer Oberfläche haben.
Electrostatic Charging Due to Separation of Ions at Interfaces: Contact Electrification of Ionic Electrets
Authors: McCarty Logan S. , Whitesides George M.
Published: February 2008

This Review discusses ionic electrets: their preparation, their mechanisms of formation, tools for their characterization, and their applications. An electret is a material that has a permanent, macroscopic electric field at its surface; this field can arise from a net orientation of polar groups in the material, or from a net, macroscopic electrostatic charge on the material. An ionic electret is a material that has a net electrostatic charge due to a difference in the number of cationic and anionic charges in the material. Any material that has ions at its surface, or accessible in its interior, has the potential to become an ionic electret. When such a material is brought into contact with some other material, ions can transfer between them. If the anions and cations have different propensities to transfer, the unequal transfer of these ions can result in a net transfer of charge between the two materials. This Review focuses on the experimental evidence and theoretical models for the formation of ionic electrets through this ion‐transfer mechanism, and proposes—as a still‐unproved hypothesis—that this ion‐transfer mechanism may also explain the ubiquitous contact electrification (“static electricity”) of materials, such as organic polymers, that do not explicitly have ions at their surface.
Improved antimicrobial activity of polypropylene and cotton nonwoven fabrics by surface treatment and modification with chitosan
Authors: Abdou Entsar S. , Elkholy Said S. , Elsabee Maher Z. , Mohamed Eweis
Published: February 2008

Nonwoven polypropylene and cotton fabrics were subjected to plasma pretreatment followed by flash evaporation and radiation crosslinking acrylate polymer coating, which is based on a vacuum deposition, solvent free, process that produces high quality, uniform fabrics with various thicknesses (0.05–5.0 μm). These treated fabrics were then dipped into chitosan, carboxymethyl chitosan, and carboxymethyl chitin solution. These polysaccharides form strong complexes with the modified surface. The antimicrobial activity of these treated samples was then evaluated for their antifungal and antibacterial properties. The antifungal activity for Fusarium oxysporum f. sp. lycopersici, Verticillium albo‐atrum, and Alternaria solani (A. alternata) were examined by the disc plate method. The antibacterial activities of the modified fabrics against Clavibacter michiganensis and Pseudomonas solanacearum were also examined by the viable cell counting method. The inhibition zone of the chitosan covered samples has increased by a factor of 2–3.1 over the original pretreated samples. The chitosan‐modified fabrics showed a good antibacterial activity in killing almost 105 cells/mL within 18–23 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Uses of electron‐beam irradiation to prepare pH‐ and temperature‐sensitive hydrogels from reactive poly(vinyl alcohol) grafts
Authors: Atta Ayman M. , Elsayed Ashraf M. , Shafy Husein I.
Published: February 2008

Thermosensitive poly(vinyl alcohol)‐graft‐(maleic anhydride), PVA‐MA, and poly(vinyl alcohol)‐graft‐(N‐isopropylacrylamide maleic anhydride) (PVA‐MA‐NIPAAm) copolymers containing carboxyl groups were prepared using electron beam irradiation at dose 80 kGy. The swelling ratios of the cross‐linked gels were measured at various temperatures. The LCST values were measured using DSC technique. The temperature dependence of the swelling ratios of the cross‐linked copolymers and terpolymers were measured at different temperatures. The swelling ratios of copolymers increased with increasing temperature up to 25–38°C, then decreased. The swelling behavior of both copolymers and terpolymers was referred to formation of hydrogen bonds between amide group of NIPAAm moieties and carboxyl group in MA moieties and to hydrophobic interaction due to methyl groups of NIPAAm. The swelling behaviors of these gels were analyzed in buffer solution at various pH. Swelling ratios of all gels were relatively high and they showed reasonable sensitive to pH. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermally and mechanically enhanced epoxy resin‐silica hybrid materials containing primary amine‐modified silica nanoparticles
Authors: Chang Kung‐Chin , Lin Chang‐Yu , Lin Hui‐Fen , Chiou Sheng‐Che , Huang Wan‐Chun , Yeh Jui‐Ming , Yang Jen‐Chang
Published: February 2008

In this article, a series of hybrid materials consisted of epoxy resin matrix and well‐dispersed amino‐modified silica (denoted by AMS) nanoparticles were successfully prepared. First of all, the AMS nanoparticles were synthesized by performing the conventional acid‐catalyzed sol–gel reactions of tetraethyl orthosilicate (TEOS), which acts as acceded sol–gel precursor in the presence of 3‐aminopropyl trimethoxysilane (APTES), a silane coupling agent molecules. The as‐prepared AMS nanoparticles were then characterized by FTIR, 13C‐NMR, and 29Si‐NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in situ thermal ring‐opening polymerization reactions of epoxy resin in the presence of as‐prepared AMS nanoparticles and raw silica (RS) particles (i.e., pristine silica). AMS nanoparticles were found to show better dispersion capability in the polymer matrices than that of RS particles based on the morphological observation of transmission electron microscopy (TEM) study. The better dispersion capability of AMS nanoparticles in hybrid materials was found to lead enhanced thermal, mechanical properties, reduced moisture absorption, and gas permeability based on the measurements of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and gas permeability analysis (GPA), respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of fumed silica on the crystallization behavior and thermal properties of poly(hydroxybutyrate‐co‐hydroxyvalerate)
Authors: Ma P. M. , Wang R. Y. , Wang S. F. , Zhang Y. , Zhang Y. X. , Hristova D.
Published: February 2008

The effects of fumed silica on the crystallization behavior and thermal properties of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) were investigated. The PHBV/silica composites were prepared by a melt‐blending method. The nonisothermal crystallization, melting process, and isothermal crystallization kinetics of PHBV and PHBV/silica composites were characterized with differential scanning calorimetry. The spherulite development and morphology were observed by polarized optical microscopy. In addition, the thermal degradation properties were determined via thermogravimetric analysis. The results indicated that the melting and crystallization kinetics of PHBV were greatly affected by fumed silica, and this was due to the effective nucleation function of silica, which enhanced the crystallization process. The thermal onset degradation temperature of PHBV increased with the addition of fumed silica. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal properties of polytetrafluoroethylene/Sr2Ce2Ti5O16 polymer/ceramic composites
Authors: Subodh G. , Manjusha M. V. , Philip J. , Sebastian M. T.
Published: February 2008

Polytetrafluoroethylene (PTFE) composites filled with Sr2Ce2Ti5O16 ceramic were prepared by a powder processing technique. The structures and microstructures of the composites were investigated by X‐ray diffraction and scanning electron microscopy techniques. Differential scanning calorimetry showed that the ceramic filler had no effect on the melting point of the PTFE. The effect of the Sr2Ce2Ti5O16 ceramic content [0–0.6 volume fraction (vf)] on the thermal conductivity, coefficient of thermal expansion (CTE), specific heat capacity, and thermal diffusivity were investigated. As the vf of the Sr2Ce2Ti5O16 ceramic increased, the thermal conductivity of the specimen increased, and the CTE decreased. The thermal conductivity and thermal expansion of the PTFE/Sr2Ce2Ti5O16 composites were improved to 1.7 W m−1 °C−1 and 34 ppm/°C, respectively for 0.6 vf of the ceramics. The experimental thermal conductivity and CTE were compared with different theoretical models. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Electrical‐transport properties of iodine‐doped conducting polyaniline
Authors: Sarkar A. , Ghosh P. , Meikap A. K. , Chattopadhyay S. K. , Chatterjee S. K. , Chowdhury P. , Roy K. , Saha B.
Published: February 2008

We investigated the electrical‐transport properties of hydroiodic acid doped polyaniline in the temperature range 77–300 K, applying magnetic field strength to a maximum of 1 T in the frequency range 20 Hz–1 MHz. The direct‐current conductivity was explained by variable range hopping theory, and the direct‐current magnetoconductivity, which was positive, was interpreted by orbital magnetoconductivity theory. The alternating‐current (ac) conductivity was found to follow the universal dielectric response σ′(f) ∝ fs, where σ′(f) is the frequency‐dependent real part of the complex ac conductivity, f is the frequency, and s is the frequency exponent. The trend in the variation of s, the temperature dependence of the frequency exponent, corroborated the fact that the correlated barrier hopping was the dominating charge‐transport mechanism. The ac conductivity also showed a positive variation with magnetic field, which could be interpreted by this theory. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of comonomer type and concentration on the equilibrium swelling and volume phase transition temperature of N‐isopropylacrylamide‐based hydrogels
Authors: Cortés J. A. , Mendizábal E. , Katime I.
Published: February 2008

The effect of incorporating a hydrophilic monomer into poly(N‐isopropylacrylamide) (polyNIPA) hydrogels on the equilibrium swelling and the volume phase transition temperature is reported here. A nonionizable monomer (acrylamide) and three ionizable monomers (itaconic acid, 2‐ethoxyethyl monoitaconate, and 2,2‐(2‐ethoxyethyl) monoitaconate) were studied. Hydrogels with larger swelling capacity than that of the polyNIPA hydrogel were obtained. With the exception of the hydrogel containing 2,2‐(2‐ethoxyethyl) monoitaconate, which did not exhibit the de‐swelling phenomena, the rest showed a volume phase transition. The hydrogels containing 85 wt % acrylamide and 15 wt % comonomer presented the higher shrinking ratio. For some compositions, the Tc of the polyNIPA hydrogel was within the desired temperature range (38–41°C) for controlled‐drug delivery in the human body. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
The application of microencapsulated phase‐change materials to nylon fabric using direct dual coating method
Authors: Koo Kang , Park Youngmi , Choe Jongdeok , Kim Eunae
Published: February 2008

The fabrication of functional textiles able to provide thermal regulation and comfort for the body has attracted increasing interest in recent years. This research investigated fabric coatings containing energy absorbing, temperature stabilizing, phase‐change material microcapsules (PCMMcs), and their methods of application. Specifically, a coated fabric was directly prepared by a dual‐type coating method, in which the PCMMcs were dispersed in a polyurethane coating solution with no binder. The thermal performances of the dual‐coated samples were evaluated by differential scanning calorimetry, and their physical characteristics were examined by scanning electron microscopy, thermal vision camera, porosity, water vapor transmission rate (WVTR), and water entry pressure (WEP) analyses. Furthermore, the microclimate characteristics of the thermally enhanced fabrics were investigated under experimental conditions using a human‐clothing‐environment (HCE) simulator system. The study results confirmed the superior performance of the dual‐coated fabrics in terms of thermal regulation and body comfort, compared with those coated by the dry or wet coating method, because of the improved WEP, WVTR, and thermal performance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Structure‐property relationship of L‐tyrosine‐based polyurethanes for biomaterial applications
Authors: Sarkar Debanjan , Yang Jui‐Chen , Lopina Stephanie T.
Published: February 2008

The structure‐property relationship of L‐tyrosine‐based polyurethanes was demonstrated by using different polyols and diisocyanates. L‐tyrosine‐based chain extender, desaminotyrosyl tyrosine hexyl ester (DTH), was used to synthesize a series of polyurethanes. Polyethylene glycol (PEG) or poly caprolactone diol (PCL) was used as the soft segment and hexamethylene diisocyanate (HDI) or dicyclohexylmethane 4,4′‐diisocyanate (HMDI) was used with DTH as the hard segment. The polyurethanes were characterized to investigate the effect of structure on different polyurethane properties. From FTIR and DSC, these polyurethanes exhibit a wide range of morphology from phase‐mixed to phase‐separated structure. The decreasing molecular weight of the PEG soft segment leads to relatively more phase mixed morphology whereas for PCL‐based polyurethanes the extent of phase mixing is less with decreasing PCL molecular weight. Results show that PCL‐based polyurethanes are mechanically stronger than PEG‐based polyurethanes but PCL‐based polyurethanes degrade slower and absorb less water compared with PEG‐based polyurethanes. The HMDI‐based polyurethanes are less crystalline and comparatively more hydrophobic than HDI‐based polyurethanes. The characterization results show that the polyurethane properties are directly related to the structure and can be varied easily for a different set of properties that are pertinent for biomaterial applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Determination of the onset of shear thinning of polydimethylsiloxane
Authors: Hadjistamov Dimiter
Published: February 2008

The shear stress and the first normal stress difference were simultaneously measured in shear flow start‐up experiments and a subsequent stress relaxation. The measured polydimethylsiloxane show shear thinning flow behavior with a first Newtonian region up to the shear rate at the onset of shear thinning. We found that the shear stress and the first normal stress difference have an equal shear rate at the onset of shear thinning. The shear stress at the onset of shear thinning does not depend on the molecular weight of the polymer and on temperature. Similar to the viscosity master curve, it is possible to create a normal stress master curve, outgoing from the first normal stress coefficient. The shear rate at the onset of shear thinning is estimated from the viscosity master curve and the shear rate at the onset of normal stress thinning from the normal stress master curve. The shear stress and the first normal stress difference have similar transient behavior with start‐up stress curves without maximum in stress growth experiments with shear rates from the first Newtonian region. The shear flow start‐up experiment with the shear rate at the onset of shear thinning leads to the first indication of an overshoot of the start‐up curve. The shear flow start‐up experiments with shear rates from the shear thinning region show start‐up curves with a maximum for the shear stress and for the first normal stress difference. It was found that the shear rate at the onset of shear thinning and the shear rate at the onset of normal stress thinning, determined by the shear flow start‐up measurements, are equal to the values obtained from the master curves. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Impedance spectroscopy of N‐substituted oligo‐oxyethylene polypyrrole films
Authors: Cihaner Atilla , Önal Ahmet M.
Published: February 2008

The electrochemical properties of neutral (dedoped) and oxidized (doped) poly(1,11‐bis(1,1‐pyrrole)‐3,6,9‐trioxaundecane) (poly‐I) film electrodes were investigated using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques. Poly‐I was deposited on glassy carbon electrode (GCE) from acetonitrile solution containing 5.0 × 10−3M 1,11‐bis(1,1‐pyrrole)‐3,6,9‐trioxaundecane (I) and 0.1M LiClO4 supporting electrolyte. Doped poly‐I exhibits a single semicircle in its complex‐capacitance plots, indicating a single dominant ion transport process, together with high capacitance values. These features make this polymer film a candidate for an energy storage material. Also, poly‐I can be a candidate as a sensory material for the detection of Ag+ based on impedance parameters. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Curing behavior and properties of the cured resin based on bismaleimide, bisoxazoline, and oleic acid ternary copolymer
Authors: Li Youqing , Li Shengfang , Tang Heqing
Published: February 2008

The curing behavior and properties of bismaleimide (BMI), bisoxazoline (1,3‐PBO), and oleic acid ternary copolymers are investigated. It is found that the cure temperature of BMI/1,3‐PBO or BMI/1,3‐PBO/oleic acid could be lowered, compared with that of BMI. The reason lies in the copolymerization reaction between BMI, 1,3‐PBO, and oleic acid. SEM results confirm that 1,3‐PBO and oleic acid could toughen BMI system because of the formation of ester–amide bonds and the long fat chain of oleic acid. The cured resins from BMI/1,3‐PBO or BMI/1,3‐PBO/oleic acid have superior heat resistance and water resistance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Development of new heterobicationic monomethine dyes as effective photoinitiator of free radical polymerization in visible‐light region
Authors: Kabatc Janina , Kaczorowska Mirosława , Jędrzejewska Beata , Pączkowski Jerzy
Published: February 2008

The dye initiators consisting of N‐[3‐(p‐alkylpyridine)propyl]‐2‐[N‐(3‐bromopropyl)quinoline]‐2‐methylenebenzotiazolium diiodides as chromophores and n‐butyltriphenylborate anion as electron donor were prepared to achieve an efficient photoinitiator of free radical polymerization in a visible‐light region. The relative photoinitiating efficiencies of novel photoinitiators of vinyl monomers polymerization were evaluated. The results obtained clearly documented that the bicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Impact of heterodimerization on intracellular localization of the ecdysteroid receptor (EcR)
Authors: Nieva Claudia , Spindler‐Barth Margarethe , Spindler Klaus‐Dieter
Published: February 2008

Initially, nuclear import of the ecdysteroid receptor (EcR) in vertebrate cells (CHO‐K1 and COS‐7) does not afford a heterodimerization partner. Later on, EcR is retained in the nucleus only in the presence of a heterodimerization partner. Ultraspiracle (Usp) is more efficient compared to its vertebrate orthologue RXR and leads to an exclusively nuclear localization of EcR even in the absence of ligand. The DNA binding domain of the heterodimerization partner is important for retainment of EcR in the nucleus as shown by Usp4 (UspR130C), which has lost its DNA binding capability. The C‐terminal end of Usp (UspΔ205‐508) encompassing the C‐terminal part of the D‐domain and the E‐ and F‐domains are essential for retainment of EcR in the nucleus. Nuclear localization is further influenced by cell‐specific factors, since hormone and heterodimerization stabilizes the EcR protein in a cell‐specific way. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc.
Synthesis and Monoamine Oxidase Inhibitory Activities of 1‐Thiocarbamoyl‐3,5‐diphenyl‐4,5‐dihydro‐1H‐pyrazole Derivatives
Authors: Palaska Erhan , Aydin Firat , Uçar Gülberk , Erol Dilek
Published: February 2008

Ten new 1‐thiocarbamoyl‐3‐(phenyl and/or 4‐substituted phenyl)‐5‐(3,4‐dimethoxyphenyl and/or 2‐chloro‐3,4‐dimethoxyphenyl)‐4,5‐dihydro‐1H‐pyrazole derivatives were synthesized by reacting 1,3‐diphenylpropen‐1‐ones and thiosemicarbazide. The chemical structures of the compounds were verified by means of their IR, 1H‐NMR, ESI‐MS spectroscopic data and elementary analyses. All the compounds were investigated for their ability to selectively inhibit monoamine oxidase (MAO) by in‐vitro tests. Monoamine oxidase was isolated and purified from the mitochondrial extracts of rat‐liver homogenates and human platelets. Monoamine oxidase inhibitory activities of the compounds were compared with pargyline and clorgyline. Most of the compounds inhibited the total activity of rat liver homogenates. The monoamine oxidase‐A inhibitory effects of 1‐thiocarbamoyl‐3‐(4‐methoxyphenyl)‐5‐(3,4‐dimethoxyphenyl)‐4,5‐dihydro‐1H‐pyrazole and 1‐thiocarbamoyl‐3‐(4‐methoxyphenyl)‐5‐(2‐chloro‐3,4‐dimethoxyphenyl)‐4,5‐dihydro‐1H‐pyrazole were detected as potent as clorgyline. Selective and irreversible inhibition of rat liver monoamine oxidase‐A by synthesized compounds have promising features for designing the new selective monoamine oxidase A inhibitors as potent and reliable anti‐depressants in the future.
Finding and using journal‐article components: Impacts of disaggregation on teaching and research practice
Authors: Sandusky Robert J. , Tenopir Carol
Published: February 2008

This article reports the results of a study into the use of discrete journal‐article components, particularly tables and figures extracted from published scientific journal articles, and their application to teaching and research. Sixty participants were introduced to and asked to perform searches in a journal‐article component prototype that presents individual tables and figures as the items returned in the search results set. Multiple methods, including questionnaires, observations, and structured diaries, were used to collect data. The results are analyzed in the context of previous studies on the use of scientific journal articles and in terms of research on scientists' use of specific journal‐article components to find information, assess its relevance, read, interpret, and disaggregate the information found, and reaggregate components into new forms of information. Results indicate that scientists believe searching for journal‐article components has value in terms of (a) higher precision result sets, (b) better match between the granularity of the prototype's index and the granularity of the information sought for particular tasks, and (c) fit between journal‐article component searching and the established teaching and research practices of scientists.
Identification of novel small molecule enhancers of protein production by cultured mammalian cells
Authors: Allen Martin J. , Boyce James P. , Trentalange Michael T. , Treiber David L. , Rasmussen Brian , Tillotson Benjamin , Davis Raymond , Reddy Pranhitha
Published: February 2008

Small molecule additives to cell culture media (e.g., sodium butyrate) that are capable of enhancing the expression of recombinant proteins have significant utility in the production and manufacture of therapeutic polypeptides. To identify novel small molecule enhancers (SMEs) of recombinant protein expression in Chinese Hamster Ovary (CHO) cells, we screened two separate small molecule libraries for compounds capable of enhancing the expression of either a fluorescent reporter protein or a monoclonal antibody. Several compounds that increased recombinant protein expression were identified, and these compounds fell into three broad classes: (1) aromatic carboxylic acids, (2) hydroxamic acids, and (3) acetamides. We examined the impact of SME addition to CHO cell cultures expressing different classes of recombinant proteins including monoclonal antibodies (MAbs). For CHO cell pools or clones grown in production shake‐flasks or bioreactors, recombinant protein titers up to 60% higher than control cultures were observed. Analysis of mRNA levels suggest that transcriptional activation plays a role in the expression enhancement seen for some SMEs, but other mechanisms may be involved for at least one compound. Finally, we tested many of the identified SMEs for their ability to increase MAb production by a hybridoma cell line. Hexanohydroxamic acid increased shake‐flask MAb production by 40% relative to a control. Taken together, these data demonstrate the potential utility of the compounds in the production of therapeutically relevant proteins from diverse cell‐based production systems. Biotechnol. Bioeng. 2008;100: 1193–1204. © 2008 Wiley Periodicals, Inc.
Supracondylar process of the humerus: Study on 375 Caucasian subjects in Cologne, Germany
Authors: Natsis Konstantinos
Published: February 2008

This study documents the prevalence of the supracondylar process of the humerus in the Caucasian subjects in a German dissecting room along with its morphology, height, and site by using an electronic digimatic caliper. Seven hundred and fifty dried humeri from 375 Causcasian cadavers were examined at the Department of Anatomy in the University of Cologne, Germany. The supracondylar process was found in 10 out of the 750 (1.3%) dried humeri from 10 individuals (2.7%). In five of these 10 bones, the supracondylar process was in the form of a tubercle. In the others it was a spine of average height 9.5 mm (range, 7.7–12.3 mm). The average distance of the supracondylar process from the medial epicondyle was 59.8 mm, ranging between 40.5 and 79.0 mm. The supracondylar process was more common on the left humerus (90%) and in male subjects (60%) (both P < 0.01). None of the processes we observed was bilateral. Literature review indicated that the supracondylar process appears in 0.4–2% of Caucasians and in 0.2–2.8% of their humeri. Clin. Anat. 21:138–141, 2008. © 2008 Wiley‐Liss, Inc.
A cross‐national examination of consumer perceived risk in the context of non‐deceptive counterfeit brands
Authors: Veloutsou Cleopatra , Bian Xuemei
Published: February 2008

This study investigates the relationships between six identified dimensions of perceived risk and the overall risk, and also their explanatory power to the overall risk when purchasing counterfeit brands in two different contexts. Using a self‐administered instrument, a total of 525 responses were collected, 230 from the UK and 295 from China. The results support the hypothesised significant interrelationship between the dimensions of perceived risk in both contexts. However there are some differences. The models have a different exploratory power, with the one based on the British sample being stronger, while a somewhat different combination of the risk dimensions seems to predict the overall risk in each context. The psychological risk is the only dimension of risk that with no doubt contributes to the formation of the overall risk in both contexts. Although one could argue that when purchasing counterfeits social risk could be an issue, the evidence reported in this study does not support the view.

Copyright © 2008 John Wiley & Sons, Ltd.
Single‐Step Electron Transfer on the Nanometer Scale: Ultra‐Fast Charge Shift in Strongly Coupled Zinc Porphyrin–Gold Porphyrin Dyads
Authors: Fortage Jérôme , Boixel Julien , Blart Errol , Hammarström Leif , Becker Hans Christian , Odobel Fabrice
Published: February 2008

The synthesis, electrochemical properties, and photoinduced electron transfer processes of a series of three novel zinc(II)–gold(III) bisporphyrin dyads (ZnPSAuP+) are described. The systems studied consist of two trisaryl porphyrins connected directly in the meso position via an alkyne unit to tert‐(phenylenethynylene) or penta(phenylenethynylene) spacers. In these dyads, the estimated center to center interporphyrin separation distance varies from 32 to 45 Å. The absorption, emission, and electrochemical data indicate that there are strong electronic interactions between the linked elements, thanks to the direct attachment of the spacer on the porphyrin ring through the alkyne unit. At room temperature in toluene, light excitation of the zinc porphyrin results in almost quantitative formation of the charge shifted state .+ZnPSAuP., whose lifetime is in the order of hundreds of picoseconds. In this solvent, the charge‐separated state decays to the ground state through the intermediate population of the zinc porphyrin triplet excited state. Excitation of the gold porphyrin leads instead to rapid energy transfer to the triplet ZnP. In dichloromethane the charge shift reactions are even faster, with time constants down to 2 ps, and may be induced also by excitation of the gold porphyrin. In this latter solvent, the longest charge‐shifted lifetime (τ=2.3 ns) was obtained with the penta‐(phenylenethynylene) spacer. The charge shift reactions are discussed in terms of bridge‐mediated super‐exchange mechanisms as electron or hole transfer. These new bis‐porphyrin arrays, with strong electronic coupling, represent interesting molecular systems in which extremely fast and efficient long‐range photoinduced charge shift occurs over a long distance. The rate constants are two to three orders of magnitude larger than for corresponding ZnPAuP+ dyads linked via meso‐phenyl groups to oligo‐phenyleneethynylene spacers. This study demonstrates the critical impact of the attachment position of the spacer on the porphyrin on the electron transfer rate, and this strategy can represent a useful approach to develop molecular photonic devices for long‐range charge separations.
Synthesis and Characterisation of Helical β‐Peptide Architectures that Contain (S)‐β3‐HDOPA(Crown Ether) Derivatives
Authors: Dutot Laurence , Gaucher Anne , Elkassimi Khadidja , Drapeau Jeremy , Wakselman Michel , Mazaleyrat Jean‐Paul , Peggion Cristina , Formaggio Fernando , Toniolo Claudio
Published: February 2008

A new set of β‐amino acids that carry various crown ether receptors on their side chains of the general formula (S)‐β3‐HDOPA(crown ether) (HDOPA: homo‐3,4‐dihydroxyphenylalanine; (crown ether): [15]crown‐5 ([15‐C‐5]), [18]crown‐6 ([18‐C‐6]), [21]crown‐7 ([21‐C‐7]), 1,2‐Benzo‐[24]crown‐8 ([Benzo‐24‐C‐8]) and (R)‐Binol‐[20]crown‐6 ([(R)‐Binol‐20‐C‐6])) was prepared. Peptides that are based on these new crowned β‐amino acids combined with (1S,2S)‐ACHC (2‐aminocyclohexanecarboxylic acid), which is known to be a potent 314‐helix inducer, to the hexamer level, with two crowned residues at the i and i+3 positions of the main‐chain, were synthesized in solution by stepwise coupling using Boc‐Nα‐protection (Boc: tert‐butoxycarbonyl) and the EDC/HOAt C‐activation method. Their conformational analysis was performed by using FTIR absorption, NMR and CD spectroscopy techniques. Our results are in full agreement with a 314‐helix conformation.
Homochiral Laminar Europium Metal–Organic Framework with Unprecedented Giant Dielectric Anisotropy
Authors: Qu Zhi‐Rong , Ye Qiong , Zhao Hong , Fu Da‐Wei , Ye Heng‐Yun , Xiong Ren‐Gen , Akutagawa Tomoyuki , Nakamura Takayoshi
Published: February 2008

Hydrothermal (deuteratothermal) reaction of L‐ethyl lactate (Lig‐Et) with Eu(ClO4)3⋅6 H2O gives colorless block crystals of [Eu(Lig)2(X2O)2][ClO4] (1, X=H; 2, X=D) both of which possess a two‐dimensional laminar homochiral framework. Single‐crystal dielectric measurements reveal that 1 and 2 display a giant dielectric anisotropy approximately exceeding 100 and large isotopic effect with about 54 % enhancement along the a axis. Their ferroelectric features further confirm this respect. Crystal parameters: 1, C6H14ClO12Eu, Mr=465.58, monoclinic, C2, a=8.6786(6), b=8.3965(6), c=10.2153(7) Å, β=92.040(1)°, V=743.92(9) Å3, Z=2, ρcalcd=2.079 Mg m−3, R1=0.0508, wR2=0.1239, μ=4.448 mm−1, S=1.043; Flack=0.04(5). 2: C6H10D4ClO12Eu, Mr=469.61, monoclinic, C2, a=8.689(2), b=8.410(2), c=10.224(3) Å, β=92.057(4)°, V=746.7(3) Å3, Z=2, ρcalcd=2.089 Mg m−3, R1=0.0465, wR2=0.1150, μ=4.432 mm−1, S=1.058; Flack=0.02(5).
Discrimination in Metal‐Ion Binding to RNA Dinucleotides with a Non‐Bridging Oxygen or Sulfur in the Phosphate Diester Link
Authors: Knobloch Bernd , Nawrot Barbara , Okruszek Andrzej , Sigel Roland K. O.
Published: February 2008

Replacement of a non‐bridging oxygen in the phosphate diester bond by a sulfur has become quite popular in nucleic acid research and is often used as a probe, for example, in ribozymes, where the normally essential Mg2+ is partly replaced by a thiophilic metal ion to reactivate the system. Despite these widely applied rescue experiments no detailed studies exist quantifying the affinity of metal ions to such terminal sulfur atoms. Therefore, we performed potentiometric pH titrations to determine the binding properties of pUp(S)U3− towards Mg2+, Mn2+, Zn2+, Cd2+, and Pb2+, and compared these data with those previously obtained for the corresponding pUpU3− complexes. The primary binding site in both dinucleotides is the terminal phosphate group. Theoretically, also the formation of 10‐membered chelates involving the terminal oxygen or sulfur atoms of the (thio)phosphate bridge is possible with both ligands. The results show that Mg2+ and Mn2+ exist as open (op) isomers binding to both dinucleotides only at the terminal phosphate group. Whereas Cd(pUpU)− only exists as Cd(pUpU)${{{- \hfill \atop {\rm op}\hfill}}}$, Cd(pUp(S)U)− is present to about 64 % as the S‐coordinated macrochelate, Cd(pUp(S)U)${{{- \hfill \atop {\rm cl}/{\rm PS}\hfill}}}$. Zn2+ forms with pUp(S)U3− three isomeric species, that is, Zn(pUp(S)U)${{{- \hfill \atop {\rm op}\hfill}}}$, Zn(pUp(S)U)${{{- \hfill \atop {\rm cl}/{\rm PO}\hfill}}}$, and Zn(pUp(S)U)${{{- \hfill \atop {\rm cl}/{\rm PS}\hfill}}}$, which occur to about 33, 12 (O‐bound), and 55 %, respectively. Pb2+ forms the 10‐membered chelate with both nucleotides involving only the terminal oxygen atoms of the (thio)phosphate bridge, that is, no indication of S binding was discovered in this case. Hence, Zn2+ and Cd2+ show pronounced thiophilic properties, whereas Mg2+, Mn2+, and Pb2+ coordinate to the oxygen, macrochelate formation being of relevance with Pb2+ only.
Concise Total Synthesis of the Thiazolyl Peptide Antibiotic GE2270 A
Authors: Delgado Oscar , Müller H. Martin , Bach Thorsten
Published: February 2008

The potent antibiotic thiazolylpeptide GE2270 A was synthesized starting from N‐tert‐butyloxycarbonyl protected valine in a longest linear sequence of 20 steps and with an overall yield of 4.8 %. Key strategy was the assembly of the 2,3,6‐trisubstituted pyridine core by consecutive cross‐coupling reactions starting from 2,6‐dibromo‐3‐iodopyridine. The complete Southern fragment was installed by Negishi cross‐coupling of 3‐zincated 2,6‐dibromopyridine at the terminal 2‐iodothiazole of a trithiazole (87 %). The substituent at C‐6 representing the Northern part of the molecule was introduced in form of the truncated tert‐butyl 2‐bromothiazole‐4‐carboxylate after metalation to a zinc reagent by another Negishi cross‐coupling (48 %). Decisive step of the whole sequence was the macrocyclization to a 29‐membered macrolactam, which was conducted as an intramolecular Stille cross‐coupling occurring at C‐2 of the pyridine core and providing the desired product in 75 % yield. The required stannane was obtained by amide bond formation (87 %) between a complex dithiazole fragment representing the Eastern part of GE2270 A and a 3,6‐disubstituted 2‐bromopyridine. Final steps included attachment of a serine‐proline amide dipeptide to the Northern part of the molecule (65 %), formation of the oxazoline ring and silyl ether deprotection (55 % overall).