bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular cloning and pharmacological characterization of porcine melanocortin-3 receptor
Authors: Fan Zhen-Chuan , Sartin James L , Tao Ya-Xiong
Published: January 2008

Mouse gene targeting studies revealed that the melanocortin-3 receptor (MC3R) affected feeding efficiency and fat storage in mice. The functions of the MC3R in other mammalian species remain to be investigated. We are interested in exploring the functions of the porcine MC3R (pMC3R) in regulating fat storage because of the economical importance of swine industry. Although nucleotide sequences of MC3Rs from several species have been reported, pMC3R had not been cloned and sequenced. We reported herein the molecular cloning and pharmacological analysis of the pMC3R. Sequence analysis revealed that pMC3R was highly homologous (>80%) at nucleotide and amino acid sequences to human, rat, and mouse MC3Rs. With human MC3R (hMC3R) as a control, the binding and signaling properties of pMC3R were investigated using several agonists including α- and γ-melanocyte-stimulating hormone (α- and γ-MSH), d-Trp8-γ-MSH, and [Nle4-d-Phe7]-MSH (NDP-MSH) and the natural antagonist agouti-related protein (AgRP). The results showed that pMC3R bound NDP-MSH with the highest affinity followed by d-Trp8-γMSH, γ-, and α-MSH. The same ranking was also found for hMC3R, although pMC3R had two- to ninefold higher affinities for these ligands. Both pMC3R and hMC3R bound AgRP with high affinity. d-Trp8-γ-MSH was the most potent agonist to stimulate cAMP generation followed by NDP-, α-, and γ-MSH. This ranking was the same as that of hMC3R. The availability of pMC3R and its pharmacological characteristics will facilitate the investigation of pMC3R in regulating food intake and fat storage.
Expression of vasopressin receptors in ACTH-independent macronodular bilateral adrenal hyperplasia causing Cushing's syndrome: molecular, immunohistochemical and pharmacological correlates
Authors: Louiset E , Contesse V , Groussin L , Cartier D , Duparc C , Perraudin V , Bertherat J , Lefebvre H
Published: January 2008

Cortisol secretion in ACTH-independent macronodular adrenal hyperplasia (AIMAH) causing Cushing's syndrome can be controlled by illegitimate receptors. The aim of the present study was to characterize the molecular, immunohistochemical, and pharmacological profiles of vasopressin receptors in cells derived from three patients with AIMAH (H1–H3), in order to evaluate the role of ectopic vasopressin receptors in the physiopathology of hypercortisolism. Expression of mRNAs encoding the vasopressin receptor types (V1a, V1b, and V2) were analyzed by RT-PCR in adrenal tissues. The presence of V1a and V2 receptors was studied by immunohistochemistry on adrenal sections. The pharmacological profiles of vasopressin receptors involved in the control of cortisol secretion were investigated using the V1a receptor antagonist SR49059 and the V2 receptor agonist [deamino-Cys1, Val4, d-Arg8]-vasopressin on cultured cells. The V1a receptor protein was present and functional in H1 and H3 tissues, whereas the V1b receptor was not expressed in any of the tissues. RT-PCR experiments revealed that V2 receptor mRNAs were detected in the three tissues. In contrast, immunohistochemical and cell incubation studies showed that the V2 receptor was involved in the stimulatory effect of AVP on cortisol secretion in H1 and H2, but not in H3 cells. Taken together, these data show that expression of functional ectopic V2 receptors and repression of eutopic V1a receptor can coexist in some hyperplastic corticosteroidogenic tissues. They also reveal that immunohistochemical and incubation studies are essential for the characterization of ectopic receptors actually involved in the control of cortisol secretion by AIMAHs.
TSH stimulates adipogenesis in mouse embryonic stem cells
Authors: Lu Min , Lin Reigh-Yi
Published: January 2008

Although TSH is the main regulator of thyroid growth and function, TSH binding activity in fat has long been reported. Since the TSH receptor (TSHR) has been detected in both preadipocytes and adipocytes, we hypothesized that it may play a role in adipose differentiation. Here, we use an in vitro model of adipogenesis from mouse embryonic stem (ES) cells to define TSH function. Directed differentiation of ES cells into the adipose lineage can be achieved over a 3-week period. Although adipocyte differentiation is initiated early in the development of cultured ES cells, TSHR up-regulation is precisely correlated with terminal differentiation of those adipocytes. The adipocytes express TSHR on the cell surface and respond to TSH with increased intracellular cAMP production, suggesting the activation of the protein kinase A signaling pathway. To determine whether TSH impacts adipogenesis, we examined how adipocytes responded to TSH at various points during their differentiation from cultured ES cells. We found that TSH greatly increases adipogenesis when added in the presence of adipogenic factors. More importantly, our data suggest that TSH also stimulates adipogenesis in cultured ES cells even in the absence of adipogenic factors. This finding provides the first evidence of TSH being a pro-adipogenic factor that converts ES cells into adipocytes. It further highlights the potential of ES cells as a model system for use in the study of TSH's role in the regulation of physiologically relevant adipose tissue.
A study on the effects of diatomite blend in natural pozzolan-blended cements
Authors: Yilmaz B.
Published: January 2008

The aim of this study was to examine usability of diatomite, a natural amorphous and porous raw material, as an additional blend in an effort to improve the performances of natural pozzolan-blended cements. To this aim, varying proportions of pozzolan, diatomite and pozzolandiatomite-blended cements were prepared and chemical, physical, mechanical, mineralogical and microstructural tests were applied to the resulting cements. The test results indicated that diatomite blend may be effective in improving pozzolanic properties, reducing setting time, reducing alkali content and increasing early-ultimate strengths of pozzolan-blended cements.
Nitroimidazoles. V. Synthesis and anti-HIV evaluation of new 5-substituted piperazinyl-4-nitroimidazole derivatives
Authors: Al-Soud Yaseen , Al-Masoudi Najim , Hassan Hamed , De Clercq Erik , Pannecouque Christophe
Published: January 2008

Nitroimidazoles. V. Synthesis and anti-HIV evaluation of new 5-substituted piperazinyl-4-nitroimidazole derivatives

A series of 2-alkylthio-1-[4-(1-benzyl-2-ethyl-4-nitro-1H- -imidazol-5-yl)-piperazin-1-y]lethanones (3-9) and alkyl- [4-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-yl)-piperazin- -1-yl)ketones (11-20) as well as the indole analogue22were synthesized from 4-nitro-5-piperazinyl imidazole derivative1, with the aim to develop newly non-nucleoside reverse transcriptase inhibitors (NNRTIs). The newly synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compound2showed inhibition of HIV-1 (EC50 0.45 mg mL-1) and HIV-2 (0.50 mg mL-1), while9showed inhibition of HIV-1 (EC502.48 mg mL-1, SI = 4).
Ketorolac-dextran conjugates: Synthesis, in vitro and in vivo evaluation
Authors: Vyas Savita , Trivedi Piyush , Chaturvedi Subhash
Published: January 2008

Ketorolac-dextran conjugates: Synthesis,in vitroandin vivoevaluation

Ketorolac is a non-steroidal anti-inflammatory drug. Dextran conjugates of ketorolac (KD) were synthesized and characterized to improve ketorolac aqueous solubility and reduce gastrointestinal side effects. An N-acylimidazole derivative of ketorolac (KAI) was condensed with a model carrier polymer, dextran of different molecular masses (40000, 60000, 110000 and 200000). IR spectral data confirmed formation of ester bonding. Ketorolac contents were evaluated by UV-spectrophotometric analysis. The molecular mass was determined by measuring viscosity using the Mark-Howink-Sakurada equation. Invitrohydrolysis studies were performed in aqueous buffers (pH 1.2, 7.4, 9) and in 80% (V/V) human plasma (pH 7.4). At pH 9, a higher rate of ketorolac release from KD was observed as compared to aqueous buffer of pH 7.4 and 80% human plasma (pH 7.4), following first-order kinetics.In vivobiological screening in mice and rats indicated that conjugates retained analgesic and anti-inflammatory activities with significantly reduced ulcerogenicity compared to the parent drug.
Chitosan inserts for periodontitis: Influence of drug loading, plasticizer and crosslinking on in vitro metronidazole release
Authors: Barat Romi , Srinatha Anegundha , Pandit Jayanta , Anupurba Shampa , Mittal Neelam
Published: January 2008

Chitosan inserts for periodontitis: Influence of drug loading, plasticizer and crosslinking onin vitrometronidazole release

Chitosan based metronidazole (MZ) inserts were fabricated by the casting method and characterized with respect to mass and thickness uniformity, metronidazole loading andin vitrometronidazole release kinetics. The fabricated inserts exhibited satisfactory physical characteristics. The mass of inserts was in the range of 5.63 ± 0.42 to 6.04 ± 0.89 mg. The thickness ranged from 0.46 ± 0.06 to 0.49 ± 0.08 mm. Metronidazole loading was in the range of 0.98 ± 0.09 to 1.07 ± 0.07 mg except for batch CM3 with MZ loading of 2.01 ± 0.08 mg. The inserts exhibited an initial burst release at the end of 24 h, irrespective of the drug to polymer ratio, plasticizer content or cross-linking. However, further drug release was sustained over the next 6 days. Cross-linking with 10% (m/m) of glutaraldehyde inhibited the burst release by ~30% and increased the mean dissolution time (MDT) from 0.67 to 8.59 days. The decrease in drug release was a result of reduced permeability of chitosan due to cross-linking.
A Novel and Efficient Synthesis of Tocopheryl Quinones by Homogeneous and Heterogeneous Methyltrioxorhenium/Hydrogen Peroxide Catalytic Systems
Authors: Saladino Raffaele , Neri Veronica , Farina Angela , Crestini Claudia , Nencioni Lucia , Palamara Anna Teresa
Published: January 2008

A convenient and efficient application of heterogeneous poly(4‐vinylpyridine), poly(4‐vinylpyridine N‐oxide), and polystyrene/methylrhenium trioxide systems for the selective oxidation of tocopherols and tocopherol derivatives to the corresponding ortho‐ and para‐tocopherylquinones is described. Environment friendly, easily available, and low‐cost hydrogen peroxide (H2O2) was used as the oxygen atom donor. The antiviral activity of the newly synthesized tocopherylquinones and their parent tocopherols against influenza A virus is also reported. On the basis of the biological assay, the activity of tocopherols against influenza virus is higher than that showed by the corresponding tocopherylquinones, thus suggesting, for the first time, a drawback effect of the oxidative metabolism on the antiviral activity of these compounds.
Fast Suzuki–Miyaura Cross‐Coupling Reaction with Hexacationic Triarylphosphine Bn‐Dendriphos as Ligand
Authors: Snelders Dennis J. M. , Kreiter Robert , Firet Judith J. , van Koten Gerard , Klein Gebbink Robertus J. M.
Published: January 2008

The application of hexa[(dimethylamino)methyl]‐functionalized triphenylphosphine (1) and its benzylammonium salt, Bn‐Dendriphos (2), in the Suzuki–Miyaura cross‐coupling of aryl bromides with arylboronic acids is described. The 3,5‐bis[(benzyldimethylammonio)methyl] substitution pattern in 2 leads to a rate enhancement compared to both the non‐ionic parent compound 1 and triphenylphospine (PPh3) itself. At the same time, the resulting catalytic species are stable towards palladium black formation, even at a phosphine/palladium ratio of 1. These observations are attributed to the presence of a total of six ammonium groups in the backbone of the phosphine ligand, which presumably leads to an unsaturated phosphine‐palladium complex.
Ratiometric and selective fluorescent chemodosimeter for Cu(II) by Cu(II)‐induced oxidation
Authors: Xiang Yu , Tong Aijun
Published: January 2008

A new rhodamine derivative, rhodamine B 4‐N,N‐dimethylaminobenzaldehyde hydrazone (1), was designed for ratiometric sensing of Cu(II) selectively. A red‐shift from 515 to 585 nm was observed in the fluorescence spectrum when Cu(II) was added to 1 in acetonitrile. Other metal ions of interest showed no ratiometric response. The interaction between Cu(II) and 1 was found to be the Cu(II)‐induced oxidation of 1. Copyright © 2008 John Wiley & Sons, Ltd.
Chemiluminescence determination of bromhexine hydrochloride with morin as chemiluminescent reagent
Authors: Jiang Qingqing , Nie Fei , Lu Jiuru
Published: January 2008

A new chemiluminescence (CL) reaction was observed when cerium(IV) solution was injected into bromhexine hydrochloride–morin solution. Based on this, a flow‐injection CL method for the determination of bromhexine hydrochloride was established. A possible mechanism of the CL reaction was proposed via the investigation of the CL kinetic characteristics, the CL spectrum and the fluorescence spectra of some related substances. Under optimum conditions, the CL signal was correlated linearly with concentration of bromhexine hydrochloride over the range 2.0 × 10–9–2.0 × 10–7 g/mL, with a linear correlation of 0.9995. The detection limit was 9 × 10–10 g/mL bromhexine hydrochloride and the relative standard deviation was 1.0% (c = 2.0 × 10–8 g/mL bromhexine hydrochloride, n = 11). The method was applied to the determination of bromhexine hydrochloride in pharmaceutical preparations and human urine samples with satisfactory results. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of methacrylic monomers on phagocytes reactive oxygen species: a possible BDDMA modulating action
Authors: Nocca Giuseppina , Lupi Alessandro , De Santis Fabio , Giardina Bruno , De Palma Francesco , Chimenti Claudio , Gambarini Gianluca , De Sole Pasquale
Published: January 2008

In the last years the studies regarding the biocompatibility of dental materials investigate, in addition to the classic cytotoxic tests, the interactions between the materials and the host cells to better explain the causes of the adverse effects observed sometimes in the clinical practice. In the present study the ability of diurethane dimethacrylate (DUDMA) and 1,4‐butanediol dimethacrylate (BDDMA) methacrylic monomers present in dental composite resins to alter the functionality of peripheral blood monocytes (PBMs) and polymorphonucleate cells (PMNs) was examined. These cells are involve in the biological response to materials and in the host ability to respond to bacteria. The results obtained suggest that the examined methacrylates induce a relevant decrease of PBMs oxidative burst whereas the basal ROS production is only slightly decreased. In PMNs DUDMA induces a decrease of both basal and stimulated ROS production. BDDMA, on the contrary, it does not alter total oxidative burst in presence of stimulus while induces a statistically significant decrease of basal ROS production. Moreover this monomer alters the reaction kinetics of stimulated ROS production. The reported finding seems to indicate that this molecule could be able to stabilize PMNs in resting state and maximize their stimulated activity. Copyright © 2008 John Wiley & Sons, Ltd.
Renin‐angiotensin system inhibitors, angiotensin I‐converting enzyme gene insertion/deletion polymorphism, and cancer
Authors: van der Knaap Ronald , Siemes Claire , Coebergh Jan‐Willem W. , van Duijn Cornelia M. , Hofman Albert , Stricker Bruno H. Ch.
Published: January 2008

BACKGROUND.

Angiotensin I‐converting enzyme (ACE) inhibitors, angiotensin II antagonists, and the ACE insertion/deletion (I/D) gene polymorphism all influence serum angiotensin II action. Because angiotensin II levels have been associated with cancer, the objective of the current epidemiologic study was to investigate whether renin‐angiotensin system inhibitors and/or ACE genotypes were associated with an altered risk of colorectal, lung, breast, and prostate cancer.

METHODS.

Data were obtained from the Rotterdam Study, a population‐based, prospective cohort study with 7983 participants. Participants who had a history of 1 of the cancers of interest (n = 216) or who had a medication history <6 months (n = 88) were excluded, leaving 7679 participants, of whom the ACE genotypes could be assessed in 6670 individuals. The mean follow‐up was 9.6 years, during which 730 incident cancers occurred. The effect of medication, ACE I/D genotypes, and their interaction on cancer risk and progression was studied by using Cox proportional hazard models.

RESULTS.

Carriers of the high‐activity genotype DD had an increased risk of breast cancer compared with low‐activity II/ID genotype carriers (hazard ratio [HR], 1.47; 95% confidence interval [95% CI], 1.05–2.04), but no association was demonstrated for other cancers. DD carriers who were exposed to long‐term and high‐dose medication were at lower risk for cancer (HR, 0.28; 95% CI, 0.10–0.79). Short‐term, high‐dose users were at risk for colorectal cancer progression in the II/ID stratum (HR, 3.83; 95% CI, 1.67–8.79).

CONCLUSIONS.

Renin‐angiotensin system‐inhibiting drugs seemed to protect against cancer in individuals with the DD genotype, which was associated with high levels of ACE. Cancer 2008. © 2008 American Cancer Society.
Sir Humphry Davy: Boundless Chemist, Physicist, Poet and Man of Action
Authors: Thomas Sir John Meurig , Edwards Peter P. , Kuznetsov Vladimir L.
Published: January 2008

The years 2007 and 2008 mark the bi‐centenary of two brilliant discoveries by Sir Humphry Davy: the isolation of sodium and potassium (1807) and the subsequent first observation (1808) of the beautiful blue and bronze colours now known to be characteristic of the solvated electron1 in potassium–ammonia systems. In celebration of these dazzling discoveries, we reflect on Davy’s many extraodinary contributions to science, technology and poetry. Humphry Davy, a truly great man, of Cornish spirit, brought immeasurable benefits to humankind.
Synthesis and Redox Behavior of 1‐Azulenyl Sulfides and Efficient Synthesis of 1,1′‐Biazulenes
Authors: Shoji Taku , Higashi Junya , Ito Shunji , Toyota Kozo , Asao Toyonobu , Yasunami Masafumi , Fujimori Kunihide , Morita Noboru
Published: January 2008

The reaction of azulenes with several sulfoxides in the presence of acid anhydrides to afford the corresponding 1‐azulenylsulfonium and 1,3‐azulenediyldisulfonium ions is reported. The subsequent conversion of these ions in high yields into 1‐azulenyl methyl and phenyl sulfides and 1,3‐bis(methyl‐ and phenylthio)azulenes through treatment with diethylamine is also described. Reaction of the 1‐azulenyl sulfides with MCPBA afforded 1‐azulenyl sulfoxides, which were then efficiently transformed into 1,1′‐biazulene derivatives under acidic conditions. The redox properties of 1‐azulenyl methyl and phenyl sulfides, 1,3‐bis(methyl‐ and phenylthio)azulenes, and 1,1′‐biazulene derivatives bearing methylthio or phenylthio substituents on each azulene ring are reported based on the results of cyclic voltammetry experiments.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Skew‐Hadamard matrices of orders 436, 580, and 988 exist
Authors: Đoković Dragomir Ž.
Published: January 2008

We construct two difference families on each of the cyclic groups of order 109, 145, and 247, and use them to construct skew‐Hadamard matrices of orders 436, 580, and 988. Such difference families and matrices are constructed here for the first time. The matrices are constructed by using the Goethals‐Seidel array. © 2008 Wiley Periodicals, Inc. J Combin Designs 16: 493–498, 2008
Histological features of lymph node metastasis in patients with biliary tract cancer
Authors: Morimoto Haruki , Ajiki Tetsuo , Ueda Takashi , Sawa Hidehiro , Fujita Tsunenori , Matsumoto Ippei , Yasuda Takeo , Fujino Yasuhiro , Kuroda Yoshikazu , Ku Yonson
Published: January 2008

Background and Objectives

The presence of lymph node (LN) metastases is an important prognostic factor in patients with biliary cancers. The aim of this study was to characterize systematically the morphological features of metastatic LNs in biliary cancers.

Methods

Four hundred ninety‐six LNs (including 112 para‐aortic LNs) dissected from 47 patients with biliary cancer were examined. The diameter of the long axis (size) and the percent metastatic area relative to whole‐node area were measured from histologic specimens.

Results

The average size of metastatic LNs (9.5 mm) was significantly larger than those without metastasis (6.5 mm; P < 0.01). The optimum cut‐off size for positive LNs was >7.5 mm, but the sensitivity of this predictor of metastasis was low (60.8%). In general, metastatic area correlated significantly with the size of metastatic LNs (P = 0.023). Para‐aortic LNs contained metastasis in 7.1% of cases, and only 25% of para‐aortic LNs with a high ratio of metastatic area could be evaluated from preoperative CT scans.

Although large LNs are highly suggestive of metastasis, poor detection of many small LNs with a low percentage of metastatic area can increase risk in patients with biliary tract cancer. J. Surg. Oncol. 2008;97:423–427. © 2008 Wiley‐Liss, Inc.

Although large LNs are highly suggestive of metastasis, poor detection of many small LNs with a low percentage of metastatic area can increase risk in patients with biliary tract cancer. J. Surg. Oncol. © 2008 Wiley‐Liss, Inc.
Studying the photophysical properties of a polymerizable 1,8‐naphthalimide dye and its copolymer with styrene as potential fluorescent sensors for metal cations
Authors: Grabchev Ivo , Dumas Stephane , Chovelon Jean‐Marc
Published: January 2008

The photophysical characteristics of a polymerizable 1,8‐naphthalimide dye and its copolymer with styrene have been investigated. The functional properties of both low and high molecular weight fluorophores in the presence of different metal cations have been discussed with regard to their potential application as fluorosensors for the metal cations and protons. In acetonitrile solution the monomeric 1,8‐naphthalimide enhances its fluorescence emission in the presence of metal cations (Zn2+, Fe3+, Co2+, Pb2+, Cu2+, Ni2+, and Mn2+). In aqueous media the poly(St‐co‐MD) exhibits a selective response to Fe3+ cations. The monomeric and polymeric fluorophores also exhibit a considerable increase in their fluorescence intensity at acidic pH values (pH < 6) which suggest that they could be used as ON–OFF probes in analytical devices for signaling the presence of protons. Copyright © 2008 John Wiley & Sons, Ltd.
Magnetic hysteresis loop in antiferromagnetically coupled bilayer structures
Authors: Ma Yan , Du An
Published: January 2008

The hysteresis behavior of a bilayer film system, in which a hard ferromagnetic layer with larger anisotropy and spin‐3/2 couples with a soft ferromagnetic layer with smaller anisotropy and spin‐1 antiferromagnetically, is studied by using the Ising model and the linear cluster approach. We calculate the magnetic reversal of the soft magnetic layer at low field while keeping the saturated magnetization state of the hard magnetic layer unperturbed, and find a phenomenon of exchange bias. The influences of anisotropy, intralayer exchange in the soft magnetic layer, and the interlayer exchange on the coercivity and exchange bias in the bilayer film are discussed. It is found that increasing the interlayer coupling can enhance the exchange bias of the system, and the easy plane anisotropy in soft magnetic layers can induce the hysteresis loop moving towards positive field. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lattice energy of zinc blende (AIIIBV and AIIBVI) solids
Authors: Verma A. S. , Sharma D.
Published: January 2008

In this paper we present an expression relating the lattice energy (U in kcal/mol) for the AIIIBV and AIIBVI semiconductors with the product of ionic charges (Z1Z2) and nearest‐neighbor distance d (Å). The lattice energy of these compounds exhibit a linear relationship when plotted on a log–log scale against the nearest‐neighbor distance d (Å), but fall on different straight lines according to the ionic charge product of the compounds. A fairly good agreement has been found between the observed and calculated values of the lattice energy for AIIIBV and AIIBVI semiconductors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain solitary wave propagation in laser‐excited solids
Authors: Mirzade Fikret Kh.
Published: January 2008

Nonlinear dynamics of long 1D longitudinal waves in laser‐excited plates is investigated by taking into account the interaction of the longitudinal displacements with the temperature field and the field of concentration of non‐equilibrium (recombining) atomic point defects. The governing nonlinear equation is derived for describing the self‐consistent thermoelastic strain fields. It is found that the thermoelastic effect on the strain waves manifests itself in the appearance of dissipative terms, which describe the heat transfer and the thermoe lastic interaction caused by the strain‐induced heat releasedue to the recombination of atomic defects. The equation that describes the evolution of the amplitude of nonlinear localized waves with time in the single‐wave approximation is derived, and, on the basis of this equation, the damping increments of these waves are determined with allowance the dissipative losses. The effect of interaction of counterpropagating waves is considered. The influence of stress‐induced decay of defect complexes on the evolution of nonlinear dispersive strain waves is analyzed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bi‐stable behaviour in GaN‐based resonant tunnelling diode structures
Authors: Leconte S. , Golka S. , Pozzovivo G. , Strasser G. , Remmele T. , Albrecht M. , Monroy E.
Published: January 2008

We have investigated the vertical electronic transport in AlN/GaN/AlN double barrier structures grown by plasma‐assisted molecular‐beam epitaxy, with AlN barrier thickness of 0.5 nm and a GaN well thickness varying from 0.5 nm to 2 nm. Two different current levels were observed in different devices in all the samples, the highest one being attributed to leakage through dislocations, and the lower one to tunnelling transport through the barriers. In the sample with a well thickness of 0.5 nm, we observed a bi‐stable behaviour, with an apparent negative differential resistance in the current‐voltage characteristic when scanning the voltage from negative to positive bias. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flexible parametric models for random‐effects distributions
Authors: Lee Katherine J. , Thompson Simon G.
Published: January 2008

It is commonly assumed that random effects in hierarchical models follow a normal distribution. This can be extremely restrictive in practice. We explore the use of more flexible alternatives for this assumption, namely the t distribution, and skew extensions to the normal and t distributions, implemented using Markov Chain Monte Carlo methods. Models are compared in terms of parameter estimates, deviance information criteria, and predictive distributions. These methods are applied to examples in meta‐analysis and health‐professional variation, where the distribution of the random effects is of direct interest. The results highlight the importance of allowing for potential skewing and heavy tails in random‐effects distributions, especially when estimating a predictive distribution. We describe the extension of these random‐effects models to the bivariate case, with application to a meta‐analysis examining the relationship between treatment effect and baseline response. We conclude that inferences regarding the random effects can crucially depend on the assumptions made and recommend using a distribution, such as those suggested here, which is more flexible than the normal. Copyright © 2007 John Wiley & Sons, Ltd.
The Relationship Between Wheat Flour and Starch Pasting Properties and Starch Hydrolysis: Effect of Non‐starch Polysaccharides in a Starch Gel System
Authors: Brennan Charles S. , Suter Manfred , Luethi Thomas , Matia‐Merino Lara , Qvortrup Jacqueline
Published: January 2008

Non‐starch polysaccharides (NSPs) and celite (used as inert filler) were incorporated into wheat flour and wheat starch paste preparations at levels of 1, 2.5, and 5% in both addition and replacement modes. Pasting properties of gums were compared using a Rapid Visco Analyser. Use of guar gum and locust bean gum elevated the peak and final viscosities of the resulting pastes (when used in either addition or replacement modes), whereas arabic gum significantly reduced the peak and final viscosity properties of the pastes. Samples which comprised wheat starch yielded higher peak and final viscosity characteristics compared to wheat flour containing samples, however higher breakdown and setback values were observed for samples using wheat flour as a base compared to wheat starch. The firmness of the gels (as determined using a texture analyser) increased with the use of wheat starch compared to wheat flour. Little significant difference was observed between NSP used and mode of application (replacement or addition). In vitro starch degradation was conducted on the wheat flour gels. Guar gum and locust bean gum reduced the amount of starch degradation in these gels, whereas arabic gum and celite increased the amount of starch hydrolysis (or were similar to the control). The rate of starch hydrolysis appears to be related to the viscosity altering behaviour of the NSPs in a starch‐rich system. The results indicate that selection of NSPs is important as gum arabic has the potential to increase starch hydrolysis compared to the control.
Humour experience in schizophrenia: relationship with executive dysfunction and psychosocial impairment
Authors: Tsoi D. T.-Y. , Lee K.-H. , Gee K. A. , Holden K. L. , Parks R. W. , Woodruff P. W. R.
Published: January 2008

Background

The ability to appreciate humour is essential to successful human interactions. In this study, we hypothesized that individuals with schizophrenia would have diminished ability to recognize and appreciate humour. The relationship between humour experience and clinical symptoms, cognitive and social functioning was examined.

Method

Thirty patients with a DSM-IV diagnosis of schizophrenia were compared with 30 age-, gender-, IQ- and ethnicity-matched healthy controls. Humour recognition was measured by identification of humorous moments in four silent slapstick comedy film clips and calculated as d-prime (d′) according to signal detection theory. Humour appreciation was measured by self-report mood state and funniness ratings. Patients were assessed for clinical symptoms, theory of mind ability, executive function [using the Wisconsin Card Sorting Test (WCST)] and social functioning [using the Life Skills Profile (LSP)].

Results

Patient and control groups did not differ in the funniness ratings they attributed to the video clips. Patients with schizophrenia had a lower d′ (humour) compared to the controls, after controlling for (1) the performance of a baseline recognition task with a non-humorous video clip and (2) severity of depressive symptoms. In patients, d′ (humour) had significant negative correlation with delusion and depression scores, the perseverative error score of the WCST and the total scores of the LSP.

Conclusions

Compared with controls, patients with schizophrenia were less sensitive at detecting humour but similarly able to appreciate humour. The degree of humour recognition difficulty may be associated with the extent of executive dysfunction and thus contribute to the psychosocial impairment in patients with schizophrenia.
Risk factors for respiratory syncytial virus bronchiolitis hospital admission in New Zealand
Authors: GRIMWOOD K. , COHET C. , RICH F. J. , CHENG S. , WOOD C. , REDSHAW N. , CUNNINGHAM C. W. , PEARCE N. , KIRMAN J. R.
Published: January 2008

This study assessed risk factors for respiratory syncytial virus (RSV) hospitalization and disease severity in Wellington, New Zealand. During the southern hemisphere winter months of 2003–2005, 230 infants aged <24 months hospitalized with bronchiolitis were recruited. RSV was identified in 141 (61%) infants. Comparison with data from all live hospital births from the same region (2003–2005) revealed three independent risk factors for RSV hospitalization: birth between February and July [adjusted risk ratio (aRR) 1·62, 95% confidence interval (CI) 1·15–2·29], gestation <37 weeks (aRR 2·29, 95% CI 1·48–3·56) and Māori ethnicity (aRR 3·64, 95% CI 2·27–5·85) or Pacific ethnicity (aRR 3·60, 95% CI 2·14–6·06). The high risk for Māori and Pacific infants was only partially accounted for by other known risk factors. This work highlights the importance of RSV disease in indigenous and minority populations, and identifies the need for further research to develop public health measures that can reduce health disparities.
Estimating population status under conditions of uncertainty: the Ross seal in East Antarctica
Authors: Southwell Colin J. , Paxton Charles G.M. , Borchers David L. , Boveng Peter L. , Nordøy Erling S. , Blix Arnoldus Schytte , De La Mare William K.
Published: January 2008

The Ross seal (Ommatophoca rossii) is the least studied of the Antarctic ice-breeding phocids. In particular, estimating the population status of the Ross seal has proved extremely difficult. The Protocol on Environmental Protection to the Antarctic Treaty currently designates the Ross seal as a ‘Specially Protected Species’, contrasting with the IUCN's classification of ‘Least Concern’. As part of a review of the Ross seal's classification under the Protocol, a survey was undertaken in 1999/2000 to estimate the status of the Ross seal population in the pack ice off East Antarctica between 64–150°E. Shipboard and aerial sighting surveys were carried out along 9476 km of transect to estimate the density of Ross seals hauled out on the ice, and satellite dive recorders deployed on a sample of Ross seals to estimate the proportion of time spent on the ice. The survey design and analysis addressed the many sources of uncertainty in estimating the abundance of this species in an effort to provide a range of best and plausible estimates. Best estimates of abundance in the survey region ranged from 41 300–55 900 seals. Limits on plausible estimates ranged from 20 500 (lower 2.5 percentile) to 226 600 (upper 97.5 percentile).
Evaluating the language resources of chatbots for their potential in English as a second language
Authors: Coniam David
Published: January 2008

This paper investigates the linguistic worth of current ‘chatbot’ programs – software programs which attempt to hold a conversation, or interact, in English – as a precursor to their potential as an ESL (English as a second language) learning resource. After some initial background to the development of chatbots, and a discussion of the Loebner Prize Contest for the most ‘human’ chatbot (the ‘Turing Test’), the paper describes an in-depth study evaluating the linguistic accuracy of a number of chatbots available online. Since the ultimate purpose of the current study concerns chatbots' potential with ESL learners, the analysis of language embraces not only an examination of features of language from a native-speaker's perspective (the focus of the Turing Test), but also aspects of language from a second-language-user's perspective. Analyses indicate that while the winner of the 2005 Loebner Prize is the most able chatbot linguistically, it may not necessarily be the chatbot most suited to ESL learners. The paper concludes that while substantial progress has been made in terms of chatbots' language-handling, a robust ESL ‘conversation practice machine’ (Atwell, 1999) is still some way off being a reality.
IMPERIAL BARBARIANS: PRIMITIVE MASCULINITY IN LOST WORLD FICTION
Authors: Deane Bradley
Published: January 2008

Cecil Rhodes, the “Colossus” of late Victorian empire, proudly proclaimed himself a barbarian. He spoke of his taste for things “big and simple, barbaric, if you like,” and boasted that he conducted himself “on the basis of a barbarian” (Millin 165, 242). His famous scholarships designed to turn out men fit for imperial mastery required success in “manly outdoor sports,” a criterion Rhodes privately called the proof of “brutality” (Stead 39). Yet while Rhodes celebrated qualities he called barbaric or brutal, his adversaries seized upon the same rhetoric to revile him. During the Boer War, for instance, the tactics by which Rhodes and his friends tightened their grip on South Africa were boldly condemned by Henry Campbell-Bannerman as “methods of barbarism.” Similarly, G. K. Chesterton denounced Rhodes as nothing more than a “Sultan” who conquered the “East” only to reinforce the backward “Oriental” values of fatalism and despotism (242–44). This strange consensus, in which Rhodes and his critics could agree about his barbarity, reflects a significant uncertainty about late Victorian imperial ambitions and their relationship to “barbarism.” Clearly, the term was available both to the empire's critics as a metaphor for unprincipled or indiscriminate violence and to imperialists as a justification for their efforts to bring civilization to the Earth's dark places, to spread the gospel, and to enforce the progress of history that the anthropologist E. B. Tylor called “the onward movement from barbarism” (29). But Rhodes's cheerful assertion of his own barbarity represents something altogether different: the apparent paradox of an imperialism that openly embraces the primitive. Nor was Rhodes alone in sounding this particularly troubling version of the barbaric yawp. During the period of the New Imperialism (1871–1914), Victorian popular culture became engrossed as never before in charting vectors of convergence between the British and those they regarded as primitive, and in imagining the ways in which barbarians might make the best imperialists of all. This transvaluation of savagery found its most striking expression in the emergence of a wildly popular genre of fiction: stories of lost worlds.
About the Mechanisms of Charging in EPMA, SEM, and ESEM with Their Time Evolution
Authors: Cazaux Jacques
Published: January 2008

The physical mechanisms involved in electron irradiation of insulating specimens are investigated by combining some simple considerations of solid-state physics (trapping mechanisms of electrons and secondary electron emission) with basic equations of electrostatics. To facilitate the understanding of the involved mechanisms only widely irradiated samples having a uniform distribution of trapping sites are considered. This starting hypothesis allows development of simple models for the trapped charge distributions in ground-coated specimens as investigated in electron probe microanalysis (EPMA) as well as for the bare specimens investigated in scanning electron microscopy (SEM) and environmental SEM (ESEM). Governed by self-regulation processes, the evolution of the electric parameters during the irradiation are also considered for the first time and practical consequences in EPMA, SEM, and ESEM are deduced. In particular, the widespread idea that the noncharging condition of SEM is obtained at a critical energyE2(where δ + η = 1 with δ and η yields obtained in noncharging experiments) is critically discussed.
Microanalysis of Porous Materials
Authors: Sorbier Loïc , Rosenberg Elisabeth , Merlet Claude
Published: January 2008

A signal loss is generally reported in electron probe microanalysis (EPMA) of porous, highly divided materials like heterogeneous catalysts. The hypothesis generally proposed to explain this signal loss refers to porosity, roughness, energy losses at interfaces, or charging effects. In this work we investigate by Monte Carlo simulation all these physical effects and compare the simulated results with measurements obtained on a mesoporous alumina. A program using the PENELOPE package and taking into account these four physical phenomena has been written. Simulation results show clearly that neither porosity nor roughness, nor specific energy losses at interfaces, nor charging effects are responsible for the observed signal loss. Measurements performed with analysis of carbon and oxygen lead to a correct total of concentration. The signal loss is thus explained by a composition effect due to a carbon contamination brought by the sample preparation and to a lesser extent by a stoichiometry of the porous alumina different from a massive alumina. For this kind of high specific surface porous sample, a little surface contamination layer becomes an important volume contamination that can produce large quantification errors if the contaminant is not analyzed.
The Impact of Charging on Low-Energy Electron Beam Lithography
Authors: Mun Lau Kien , Drouin Dominique , Lavallée Eric , Beauvais Jacques
Published: January 2008

A major issue in low voltage lithography is surface charging, which
results in beam deflection presented as uneven exposure between
adjacent structures. In this study, charge-induced pattern distortions
in low-voltage energy beam lithography (LVEBL) were investigated using
a silicide direct-write electron beam lithography process. Two
methodologies have been proposed to avert charging effects in LVEBL,
namely, pattern randomizing and lithography using the crossover
voltage. Experimental results demonstrated that these methods are
effective in significantly reducing the problems associated with
charging. They indicate that charging on a sample is a function of time
interval and proximity between line structures. In addition, the
optimum time and distance between exposures for no charge-induced
pattern distortion were determined. By using the crossover voltage of
the material for lithography, charging effect can be significantly
minimized.
First experimental proof of spatial resolution improvement in a monochromized and Cs-corrected TEM
Authors: Freitag B. , Kujawa S. , Mul P. M. , Tiemeijer P. C.
Published: January 2008

Extended abstract of a paper presented at the Pre-Meeting Congress: Materials Research in an Aberration-Free Environment, at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, July 31 and August 1, 2004.
Aberration-Corrected Electron Microscopy in Nanocatalysis
Authors: Gai Pratibha L.
Published: January 2008

Extended abstract of a paper presented at the Pre-Meeting Congress: Materials Research in an Aberration-Free Environment, at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, July 31 and August 1, 2004.
The Dynamics of Nano-oxidation Reactions Visualized by in situ UHV-TEM
Authors: Yang Judith C.
Published: January 2008

Extended abstract of a paper presented at the Pre-Meeting Congress: Materials Research in an Aberration-Free Environment, at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, July 31 and August 1, 2004.
Sub-Ångstrom and sub-eV resolution with the analytical SATEM
Authors: Benner G. , Matijevic M. , Orchowski A. , Schlossmacher P. , Thesen A. , Haider M. , Hartel P.
Published: January 2008

Extended abstract of a paper presented at the Pre-Meeting Congress: Materials Research in an Aberration-Free Environment, at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, July 31 and August 1, 2004.
Spectral FRET to Measure Nitric Oxide (NO) Induced Modification of Protein Thiolate Clusters in Live Pulmonary Endothelial Cells
Authors: St Croix Claudette M , Stitt Molly S , Wasserloos Karla J , Pitt Bruce R , Watkins Simon C
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Multiple Scattering Theory for Tomography Using a Scanning Transmission Electron Microscope
Authors: Levine Zachary H.
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
The Structure of Red Clover Necrostic Mosaic Dianthovirus at 10 Å Resolution
Authors: Sherman Michael B , Orlova Elena V , Guenther Richard H , Lommel Steven A , Mikhailov Albert M , Baker Timothy S
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
The Structural and Chemical Analyzer (SCA): A New Analytical Technique for SEM
Authors: Prusnick Tim , Brooker A. D. , Bennett Robert
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Synchrotron Radiation for the Characterization of Energy Dispersive X-ray Spectrometers
Authors: Procop Mathias , Scholze Frank
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Microstructural Surface Damage Evolution During Tensile Straining of Calcium Carbonate Containing High Density Polyethylene
Authors: Nerikar P. , Dasari A. , Misra R.D.K.
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Molecular Imaging of Individual Single Cells and Human Tissues Using Synchrotron Infrared Microspectroscopy
Authors: Dumas Paul
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Carbide Inclusions in Delta-Phase Plutonium
Authors: Baros Thomas , Davis Charles C , Hawkins Heather T , Roybal Lawrence , Ruggiero Matthew  J , Valentine S J , Storey Bradford G
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
High Resolution X-ray Microscopy in the Scanning Electron Microscope
Authors: Redfern Del , Brownlow L A , Sheffield-Parker C J , Miller P R , Mayo S. C.
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Morphology/Mechanical Property Correlations in Multiphase Polyolefin Blends: An Atomic Force Microscopy Study
Authors: Mirabella Francis M
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
The Utilization of Microscopy in the Preservation of Historic Textile Artifacts
Authors: France Fenella G.
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Spectral Imaging and Automated Multivariate Statistical Analysis of the Ourique Meteorite
Authors: Kotula Paul G. , Keenan Michael R. , Michael Joseph R. , Carpenter Paul
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Energy Dispersive X-ray Spectrometry in the Scanning Electron Microscope
Authors: Newbury Dale E
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
A Standard for Sub-Ångstrom Metrology of Resolution in Aberration-Corrected Transmission Electron Microscopes
Authors: O'Keefe Michael A. , Allard Lawrence F.
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
SE and BSE Information from CNT Containing Fe at Various Accelerating Voltages
Authors: Takeuchi Shuichi , Muto Atsushi , Nakagawa Mine , White Sara , Tamochi Ryuichiro , Sato Mitsugu , Yamada Mitsuhiko , Joy David C
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Combinatorial RF Magnetron Sputtering for Rapid Materials Discovery: Methodology and Applications
Authors: Rack Philip D. , Fowlkes Jason D. , Deng Yuepeng
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Imaging Dendritic Cells: A Primer
Authors: Papworth Glen , Beer-Stolz Donna , Watkins Simon C.
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Spin Polarization in Half-Metallic CrO2
Authors: van Veenendaal Michel , Fedro Arthur J
Published: January 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.