bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety management is a virtue
Authors: Summers Angela E.
Published: July 2009

It is undeniable that safe operation and process reliability are not only compatible but highly interrelated. Reliable production units rarely have safety incidents, whereas unreliable ones tend to repeatedly experience abnormal operation. To prevent incidents, personnel, procedures, and equipment must be aligned to facilitate rapid identification and response to failures of the control system and protective safeguards. Safe and reliable performance requires minimization of the root causes that lead to abnormal and emergency operation. The challenges to accomplishing this in a timely manner are considerable, but not insurmountable.

This article discusses various challenges to sustaining safe operation of process equipment. Each challenge is introduced using a philosophical saying from a Chinese fortune cookie to remind the reader that the barriers against progress are not new but have existed from many years. In most cases, the solutions are also well known and generally require deployment of robust equipment, proven techniques, and competent resources. © 2009 American Institute of Chemical Engineers Process Saf Prog 2009
Gradual degradation of GaAs‐based quantum well lasers, creation of defects, and generation of compressive strain
Authors: Tomm Jens W. , Ziegler Mathias , Oudart Myriam , Nagle Julien , Jiménez Juan
Published: July 2009

We report on the interplay between compressive strains and defects within the active region of 980 nm emitting high‐power diode laser arrays. By analyzing photocurrent data, we show how external mechanical load caused by device packaging results in cumulative defect signatures within their active region. Furthermore, we analyze the reverse situation, where device degradation results in the generation of defect signatures and these defects subsequently act as driving force for the creation of compressive strains within the quantum well active region of the devices. Knowledge about their microscopic nature will be urgently required for creating more robust semiconductor device architectures.
Sensitivity of triple‐crystal X‐ray diffractometers to microdefects in silicon
Authors: Molodkin V. B. , Olikhovskii S. I. , Len E. G. , Kislovskii E. N. , Kladko V. P. , Reshetnyk O. V. , Vladimirova T. P. , Sheludchenko B. V.
Published: July 2009

The dynamical theory, which describes both diffraction profiles and reciprocal space maps measured from imperfect crystals with account for instrumental factors of triple‐crystal diffractometer (TCD), has been developed for adequate quantitative characterization of microdefects. Analytical expressions for coherent and diffuse scattering (DS) intensities measured by TCD in the Bragg diffraction geometry have been derived by using the generalized statistical dynamical theory of X‐ray scattering in real single crystals with randomly distributed defects. The DS intensity distributions from single crystals containing clusters and dislocation loops have been described by explicit analytical expressions. Particularly, these expressions take into account anisotropy of displacement fields around defects with discrete orientations. Characteristics of microdefect structures in silicon single crystals grown by Czochralsky‐ and float‐zone methods have been determined by analyzing the measured TCD profiles and reciprocal space maps. The sensitivities of reciprocal space maps and diffraction profiles to defect characteristics have been compared.
Critical discussion of models proposed to explain photo‐induced anisotropies in chalcogenide glasses
Authors: Fritzsche Hellmut
Published: July 2009

Different theories explaining the origin and the mechanism of the dynamic part of photo‐induced anisotropies which are observed in a large family of chalcogenide glasses will be discussed and analyzed. It is useful to distinguish two kinds of photo‐induced anisotropies, Type 1 which involves a limited concentration of bistable anisotropic defects or centers and Type 2 which encompasses most of the materials.
Amorphous research in Romania: Past, present and latest results
Authors: Popescu Mihai , Croitoru Nathan
Published: July 2009

In the early days of amorphous research, Romania was deeply involved in the development of the field of amorphous semiconductors within a close collaboration with Boris Kolomiets. The first researches in this field are discussed and further rapid developments up to the present are shown. The latest results in the field of amorphous semiconductors with special emphasis on chalcogenide glasses are presented.
Study on the effect of Jia‐Wei‐Xiao‐Yao‐San decoction on patients with functional dyspepsia
Authors: Qu Yang , Gan Hong Quan , Mei Qi Bing , Liu Li
Published: July 2009

The effect of Jia‐Wei‐Xiao‐Yao‐San (JWXYS) decoction on patients with functional dyspepsia was studied by means of electrogastrography (EGG) and symptoms of dyspepsia were assessed. Twenty patients with functional dyspepsia were selected; before and after internal treatment with JWXYS, the integrated symptoms of the patients were down‐regulated from 18.55 ± 3.24 (before treatment) to 11.65 ± 2.37 (after treatment) (p < 0.01); electrogastrography showed that all the EGG parameters of the patients were outside the normal range. After treatment with JWXYS, all these indices improved before and after dinner. The results showed that the JWXYS decoction could not only improve the symptoms, but also adjust the abnormal gastric motility and gastric myoelectrical activity of patients with functional dyspepsia. Copyright © 2009 John Wiley & Sons, Ltd.
Antifatigue activity of phenylethanoid‐rich extract fromCistanche deserticola
Authors: Cai Run‐Lan , Yang Mei‐Hua , Shi Yue , Chen Jun , Li Yong‐Chao , Qi Yun
Published: July 2009

A phenylethanoid‐rich extract (ECD) ofCistanche deserticolaY.C. Ma, a holoparasitic plant and a valuable traditional Chinese medicine, was evaluated for antifatigue activity in ICR mice. ECD (0.25, 0.50, 1.00 g/kg) was administered orally to mice for 3 weeks. The swimming time to exhaustion was longer in the treatment groups (0.50, 1.00 g/kg) than in the control group (p< 0.01). The serum creatine kinase, lactate dehydrogenase and lactic acid levels were decreased significantly in the treatment groups compared with the control group, while the contents of hemoglobin and glucose were increased significantly. In conclusion, ECD appeared to enhance the swimming capacity of mice by decreasing muscle damage, delaying the accumulation of lactic acid and by improving the energy storage. These results provide scientific evidence for the traditional Chinese medical practice ofC. deserticola. Copyright © 2009 John Wiley & Sons, Ltd.
Estimation of the relative antiinflammatory efficacies of six commercial preparations of Harpagophytum procumbens (Devil's Claw)
Authors: Ouitas Nassima Abdelouahab , Heard Charles
Published: July 2009

The current work compared the relative efficacies of six commercial formulations of H. procumbens. Each formulation was assayed for the content of harpagoside (1), harpagide (2), verbascoside (3) and 8‐O‐p‐coumaroyl harpagide (4) and, based on the recommended dosages, the total daily amounts were determined and used to establish anti‐/proinflammatory (A/P) factors. The formulations were compared using ex vivo porcine skin for their activities towards COX‐2 by Western blotting. The results showed great variation in the amounts of compounds 1–4 within the six formulations examined. The relative proportions of 1–4 also varied widely between the products and this inconsistency was reflected in the A/P factors, which correlated with the COX‐2 expression (R2 = 0.9496). Although the data support the beneficial antiinflammatory effects from the use of some of the brands tested, others would appear potentially to exacerbate inflammation. To conclude, a ratio based upon the amount and relative proportions of anti‐ and proinflammatory compounds can be used to predict relative antiinflammatory properties. Also, with access to a diversity of ostensibly similar commercial products, the patient may experience varying therapeutic responses. Finally, current pharmacopoeia monographs, which are generally concerned with a minimum harpagoside content, are inadequate for ensuring the quality of products based on H. procumbens. Copyright © 2009 John Wiley & Sons, Ltd.
Evaluation of healing and antimicrobiological effects of herbal therapy on venous leg ulcer: pilot study
Authors: Binić Ivana , Janković Aleksandar , Janković Dimitrije , Janković Irena , Vručinić Zoran
Published: July 2009

Venous leg ulcers represent a significant public health problem that will increase as the population ages. Numerous herbs and their extracts are potentially conducive to wound healing, including the ability to serve as an antimicrobial, antifungal, astringent, etc. A total of 32 patients with venous leg ulcers were randomized into two groups: a group with herbal therapy treatment (PT) (17 patients) and a control group (C) (15 patients). The investigation focused on five controls of parameter changes important for ulcer healing and the control of microbiological flora. Within‐treatment analysis of the PT group showed that, following herbal therapy treatment, there was a significant decrease in the scores of surface leg ulcer and venous leg ulcer after week 7 of treatment (p < 0.05). In group C following topical antibiotic treatment there was no significant decrease in the surface leg ulcer. Comparing the results of decreased venous leg ulcer surface of the) PT group with the C group showed a significant difference at p < 0.05 after week 7 of treatment. The number of different types of isolated bacterial species decreased significantly (p < 0.05) after the use of herbal preparations. The results of this pilot study demonstrate the healing and antimicrobiological effects of herbal therapy on non‐infected venous leg ulcer. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of Evolvulus alsinoides Linn. on learning behavior and memory enhancement activity in rodents
Authors: Nahata Alok , Patil U. K. , Dixit V. K.
Published: July 2009

In the Ayurvedic system of medicine, the whole herb of ‘Shankhpushpi’ has been employed clinically for centuries for its memory potentiating, anxiolytic and tranquilizing properties. The present study was undertaken to investigate the effects of Evolvulus alsinoides (EA), considered as Shankhpushpi on learning and memory in rodents. Nootropic activity using Cook and Weidley's pole climbing apparatus, passive avoidance paradigms and active avoidance tests were used to test learning and memory. The ethanol extract of EA and its ethyl acetate and aqueous fractions were evaluated for their memory enhancing properties. Two doses (100 and 200 mg/kg p.o.) of the ethanol extract and ethyl acetate and aqueous fractions were administered in separate groups of animals. Both doses of all the extracts of EA significantly improved learning and memory in rats. Furthermore, these doses significantly reversed the amnesia induced by scopolamine (0.3 mg/kg i.p.). Nootropic activity was compared using piracetam as the standard. EA also exhibited potent memory enhancing effects in the step‐down and shuttle‐box avoidance paradigms. Copyright © 2009 John Wiley & Sons, Ltd.
Antiviral activity of daphnoretin isolated from Wikstroemia indica
Authors: Ho Wing‐Shan , Xue Jun‐Yi , Sun Samuel S.M. , Ooi Vincent E.C. , Li Yao‐Lan
Published: July 2009

The ethanol extract of Wikstroemia indica was fractionated with organic solvents of different polarities, and various fractions were screened for their antiviral activity against respiratory syncytial virus (RSV) using a cytopathic effect (CPE) reduction assay. The ethyl acetate fraction was most active against RSV with 50% inhibition concentration (IC50) value < 3.9 μg/mL and a selectivity index (SI) > 64.1. Further isolation and purification of the fraction led to a purified compound, daphnoretin. Daphnoretin was tested for its anti‐RSV activity using a plaque reduction assay and found active against RSV, with an IC50 value of 5.87 μg/mL and SI value of 28.17. The mode of antiviral action study revealed that daphnoretin could slightly inhibit the early events of the viral infection but its effect was mainly on the later phase of the replication cycle. Copyright © 2009 John Wiley & Sons, Ltd.
Different amounts of isoflavones in various commercially available soy extracts in the light of gene expression‐targeted isoflavone therapy
Authors: Piotrowska Ewa , Jakóbkiewicz‐Banecka Joanna , Węgrzyn Grzegorz
Published: July 2009

Isoflavones are plant‐derived, biologically active compounds that are commonly used as natural drugs or diet supplements in the treatment of menopausal symptoms and as antioxidants. Recently, it was proposed that genistein (4′,5,7‐trihydroxyisoflavone) may be used in the treatment of patients suffering from Sanfilippo disease (mucopolysaccharidosis type III), a severe genetic disorder for which no therapy is available. A pilot clinical study with this novel therapy, called ‘gene expression‐targeted isoflavone therapy’ (GET IT), indicated that a standardized, genistin‐rich soy isoflavone extract is effective in the treatment of such patients. Since various isoflavone‐containing products are commercially available, the content of the main isoflavones were measured in such products. Extremely different amounts of isoflavones were determined in various products, from 0.13 to 39 mg per tablet. Only some of these products were found to be effective in inhibition of the synthesis of glycosaminoglycans (compounds whose degradation is severely impaired in mucopolysaccharidoses, including Sanfilippo disease) in cultured fibroblasts. Since in GET IT the dose of genistein is calculated per patient's body weight, the amount of this isoflavone in a tablet is crucial for this therapy. Therefore, the results presented in this report indicate that a careful choice of a proper isoflavone extract is necessary for GET IT. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of Aloe barbadensis Miller Juice on oxidative stress biomarkers in aerobic cells using Artemia franciscana as a model
Authors: Sirdaarta J. , Cock I. E.
Published: July 2009

This study reports on the induction of oxidative stress in aerobic cell systems by Aloe barbadensis Miller (Aloe vera) juice using the salt water crustacean Artemia franciscana as a model. A consistent pattern was observed in which Artemia franciscana nauplii responded to Aloe vera juice exposure with a decrease in the overall activity of redox related enzymes. Exposure of Artemia franciscana to sub‐lethal levels of Aloe vera juice resulted in a decreased activity of thioredoxin reductase, glutathione reductase and glutathione peroxidase by 34% (66% enzymatic activity), 79% (21% enzymatic activity) and 90% (10% enzymatic activity), respectively. Similarly apparent was the trend whereby the co‐exposure of the nauplii to vitamin E counteracted this effect. For each of the biomarker enzymes tested, vitamin E co‐exposure resulted in enzyme activities closer to the control value (78%, 56% and 32% of control enzymatic activities for thioredoxin reductase, glutathione reductase and glutathione peroxidase activity, respectively). These results indicate that exposure to sub‐lethal doses of Aloe vera juice induces alterations in the cellular redox status of Artemia franciscana and that the addition of vitamin E helps the Artemia franciscana nauplii to overcome/block the juice induced oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.
Structure and dissociation of cyanogen halides BrCN and ICN
Authors: Bhattacharyya I. , Mondal B. , Bera N. C. , Das A. K.
Published: July 2009

Structural properties and dissociation of cyanogen bromide BrCN, cyanogen iodide ICN, and their isomers have been studied in detail using ab initio MP2, CCSD, and CCSD(T) methods. After dissociation of BrCN and ICN, the fragmented atoms have been considered to be either in their ground state or in their valence excited states. The recent experimental value for the strength of the CN bond of CN radical has been compared with our value calculated from the dissociation of BrCN. Interesting results have been obtained when BrCN and ICN dissociated to atoms that are in their valence excited states. The structural properties of BrCN and ICN and dissociation energy of BrCN agree very well with the theoretical and experimental values wherever available. The dissociation pathways of ICN are first predicted. The isomerization energy of BrCN is compared with the existing theoretical result. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical study of {Au3(CH3NCOCH3)3}n·{2,4,7‐trinitro‐9‐fluorenone} (n = 1,2) complexes
Authors: Mendizabal Fernando
Published: July 2009

The interaction between {Au3(CH3NCOCH3)3} and {2,4,7‐trinitro‐9‐fluorenone} and the electronic structure and spectroscopic properties of {Au3(CH3N = COCH3)3}n·{2,4,7‐trinitro‐9‐fluorenone} (n = 1,2) are studied at the HF, MP2, and PBE levels. Secondary π‐interactions (Au‐fluorenone) were found to be the main contribution to short‐range stability in the {Au3(CH3NCOCH3)3}n·{2,4,7‐trinitro‐9‐fluorenone} complex. At the MP2 and PBE levels, Au‐C equilibrium distances of 292.3 and 304.0 pm and interaction energies of 105.3 and 24.9 kJ/mol were found, respectively. The absorption spectra of these complexes were calculated by the single excitation time‐dependent method at the PBE level. The theoretical values obtained are in agreement with the experimental range. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Semiempirical evaluation of the global hardness of the atoms of 103 elements of the periodic table using the most probable radii as their size descriptors
Authors: Ghosh Dulal C. , Islam Nazmul
Published: July 2009

Relying upon the fact that the density functional computation of the global hardness of the atoms of the elements are still at large and there is some mathematical in congruency between the theory and operational formula of finite difference approximation, we have suggested a radial‐dependent ansatz for evaluating global hardness of atoms as: η=a(7.2/r)+b (in eV), where, “a” and “b” are the constants and r is the absolute radius of atoms in angstrom unit. The ansatz is invoked to evaluate the global hardness of atoms of 103 element of the periodic table. The evaluated new set of global hardness is found to satisfy the sine qua non of a reasonable scale of hardness by exhibiting perfect periodicity of periods and groups and correlating the gross physicochemical properties of elements. The inertness of Hg and extreme reactivity Cs atoms are nicely correlated. The chemical reactivity and its variation in small steps in the series of lanthanide elements are also nicely reproduced. The results of the present semiempirical calculation also have strong correlation with the result of some sophisticated DFT calculation for a set of atoms. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
On the performance of eleven DFT functionals in the description of the vibrational properties of aluminosilicates
Authors: Demichelis Raffaella , Civalleri Bartolomeo , Ferrabone Matteo , Dovesi Roberto
Published: July 2009

The performance of eleven DFT functionals in describing the equilibrium structure and the vibrational spectra at the Γ point of pyrope (Mg3Al2Si3O12), forsterite (α‐Mg2SiO4), α‐quartz (α‐SiO2) and corundum (α‐Al2O3) is discussed. The four systems, for which accurate experimental data are available, are here used as a representative sample of the large aluminosilicates family. Calculations were performed with the periodic ab initio CRYSTAL code by using all‐electron Gaussian‐type basis sets. All the functionals here considered provide reasonable structural predictions, the hybrid PBE0 giving the least deviation from the experimental unit cell volumes (from −0.3% to +0.6%). At the other extreme, SVWN and SPWLSD (≃−3%) and PBE and PW91 (≃ +3%) provide the largest volume under‐ and over‐estimation, respectively. Vibrational frequencies are more accurate when computed with hybrid functionals, with the best performance provided by B3LYP and WC1LYP (mean absolute differences with respect to experiments evaluated on a set of 134 vibrational frequencies, |${\bar \Delta}$|t ≃ 5.5 cm−1). The three recently proposed GGA functionals, PBEsol, SOGGA‐PBE and WC‐PBE, provide a good description of the vibrational spectra, of the same quality as the one provided by PBE0 and B1WC (|${\bar \Delta}$|t ≃ 10 cm−1), whereas poorer results are obtained with PBE (|${\bar \Delta}$|t ≃ 17 cm−1). © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Hamiltonian for the spin quantum Hall effect solution and derivation based on an SU (2) gauge field
Authors: Bracken Paul
Published: July 2009

A Hamiltonian to describe a spin quantum Hall effect with two types of spin‐orbit coupling is introduced and the eigenfunctions and eigenvalues are obtained for it. It is shown that this Hamiltonian also results by gauging a kinetic energy Hamiltonian by an SU (2) gauge field. The Berry phase is obtained from the model wavefunction for the model and used to define a filling factor. This allows for the calculation of the spin Hall conductivity. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Input/output structure of the infinite horizon LQ bumpless transfer and its implications for transfer operator synthesis
Authors: Zheng Kai , Bentsman Joseph
Published: July 2009

The steady‐state input/output structure of the infinite horizon LQ bumpless transfer topologies for strictly proper controllers is analyzed. It is found that in these topologies (1) the steady‐state gain of the transfer function from the output of the online controller to that of the offline one is unity/asymptotically unity, and (2) the steady‐state gain of the transfer function from the input of the online controller to the output of the offline one is zero/asymptotically zero, for essentially all strictly proper controllers with the input dimension being no less than the output one. These facts (1) reveal the steady‐state gain structure of the closed‐loop transfer matrix in the standard LQ tracking problems, (2) demonstrate that the LQ bumpless transfer technique solves the ideal bumpless transfer problem for controllers with an integrator in each of their output channels, (3) reveal the structure of unavoidable signal discontinuities in the controller input/output upon transfer between controllers with non‐integrating channels, and (4) provide guidance for minimizing the above signal discontinuities and the resulting bumps in the plant output in bumpless transfer synthesis. Copyright © 2009 John Wiley & Sons, Ltd.
Biplot methodology in exploratory analysis of microarray data
Authors: Gardner‐Lubbe S. , le Roux N. J. , Maunders H. , Shah V. , Patwardhan S.
Published: July 2009

Although principal component analysis is widely used in the exploration of microarray data, the advantages of constructing a biplot as multivariate analog to a scatterplot is seldom exploited. This paper illustrates the benefits of using biplots with microarray data to (1) visually display both the treatments and genes of such extreme high‐dimensional data in a single plot, (2) relate the treatments to the underlying biological process through the use of biplot axes, and (3) to optimally separate classes and explore the differentially associated expression in genes. In this analysis, we have used gene expression measurements from human bronchial epithelial cells following exposure to whole cigarette smoke. Specifically, when exploring differences between treatments and differentially expressed genes, it is shown why the principal component biplot is not optimal and the analysis of distance biplot is introduced as an alternative to principal components. Copyright © 2009 Wiley Periodicals, Inc., Statistical Analysis and Data Mining 2: 135‐145, 2009
Entrepreneurs as theorists: on the origins of collective beliefs and novel strategies
Authors: Felin Teppo , Zenger Todd R.
Published: July 2009

What are the origins of entrepreneurial beliefs about new opportunities and the value of resources? In this article, we outline a theory and model of the emergence of entrepreneurial beliefs and novel strategies. We first summarize extant literature by highlighting both the experiential and perceptual (or observational) origins of entrepreneurial beliefs and strategies. Thereafter we carefully explicate the role that entrepreneurial theorizing plays in the emergence of novel beliefs about new opportunities and make links with experiential and perceptual arguments. We specifically discuss three key mechanisms of entrepreneurial theorizing, namely: (1) the triggering role of experiential and observational fragments; (2) the imagination of possibilities; and (3) reasoning and justification. Importantly, we also explicate the social mechanisms of entrepreneurial theorizing and the emergence of entrepreneurial beliefs and novel strategies, specifically by discussing the role of social interaction and self‐selection in entrepreneurial activity. Copyright © 2009 Strategic Management Society
Weathering the storm: the benefit of resources to high‐technology ventures navigating adverse events
Authors: De Carolis Donna Marie , Yang Yi , Deeds David L. , Nelling Edward
Published: July 2009

Technology ventures must often navigate through difficult times during their existence. In the entrepreneurship literature, however, relatively little research explores the question of how ventures weather the more acute adverse event. Analogous to captains who prepare their vessels for tumultuous waters, entrepreneurs establish the organizational characteristics to enable the survival of the initial shock of an adverse event. Thus, in this article we address the research question of what firm characteristics mitigate the impact of an adverse event based on the resource‐based perspective and organizational slack literature. Our findings point to the importance of building capabilities to enable a venture to navigate difficult times. Copyright © 2009 Strategic Management Society.
Global goodness‐of‐fit tests for group testing regression models
Authors: Chen Peng , Tebbs Joshua M. , Bilder Christopher R.
Published: July 2009

In a variety of biomedical applications, particularly those involving screening for infectious diseases, testing individuals (e.g. blood/urine samples, etc.) in pools has become a standard method of data collection. This experimental design, known as group testing (or pooled testing), can provide a large reduction in testing costs and can offer nearly the same precision as individual testing. To account for covariate information on individual subjects, regression models for group testing data have been proposed recently. However, there are currently no tools available to check the adequacy of these models. In this paper, we present various global goodness‐of‐fit tests for regression models with group testing data. We use simulation to examine the small‐sample size and power properties of the tests for different pool composition strategies. We illustrate our methods using two infectious disease data sets, one from an HIV study in Kenya and one from the Infertility Prevention Project. Copyright © 2009 John Wiley & Sons, Ltd.
When experience meets national institutional environmental change: foreign entry attempts of U.S. firms in the Central and Eastern European region
Authors: Xia Jun , Boal Kimberly , Delios Andrew
Published: July 2009

We develop an institutional change perspective to examine the tension that can exist between evolving external environmental influences and internal organizational influences on foreign entry attempts. Using data on the entries of 215 U.S. public firms made into 11 Central and Eastern European transition economies during the period of 1990–2003, we find that shifts in national institutional environments, from a socialist to a market economy, reduce the extent of challenges encountered to make a hierarchical entry, which leads to an increase in foreign hierarchical entry attempts but not necessarily to a decrease in relational entry attempts as institutional transformation. We find evidence of inertial influences as experienced entrants tend to follow their previous decisions when making subsequent entry attempts. Further, they are less responsive in their foreign entry strategies to the institutional transformation in a given host country than inexperienced firms. We also find that the experience gained from relational entries results in more hierarchical entry attempts, but hierarchical entry experience results in fewer relational entry attempts. Copyright © 2009 John Wiley & Sons, Ltd.
Astrocyte Differentiation of Neural Precursor Cells is Enhanced by Retinoic Acid Through a Change in Epigenetic Modification
Authors: Asano Hirotsugu , Aonuma Makoto , Sanosaka Tsukasa , Kohyama Jun , Namihira Masakazu , Nakashima Kinichi
Published: July 2009

Neurons, astrocytes, and oligodendrocytes—the three major cell types that comprise the central nervous system—are generated from common multipotent neural precursor cells (NPCs). Members of the interleukin-6 family of cytokines, including leukemia inhibitory factor (LIF), induce astrocyte differentiation of NPCs by activating the transcription factor signal transducer and activator of transcription 3 (STAT3). We show here that retinoic acid (RA) facilitates LIF-induced astrocyte differentiation of NPCs. RA and LIF synergistically activate the promoter of gfap, which encodes the astrocytic marker glial fibrillary acidic protein, and a putative RA response element in the promoter was found to be critical for this activation. Histone H3 acetylation around the STAT-binding site in the gfap promoter was increased in NPCs treated with RA, allowing STAT3 to gain access to the promoter more efficiently. These results suggest that RA acts in concert with LIF to induce astrocyte differentiation of NPCs through an epigenetic mechanism that involves cross-talk between distinct signaling pathways.

Disclosure of potential conflicts of interest is found at the end of this article.
A Human Stem Cell-Based Model for Identifying Adverse Effects of Organic and Inorganic Chemicals on the Developing Nervous System
Authors: Buzanska Leonora , Sypecka Joanna , Nerini-Molteni Silvia , Compagnoni Anna , Hogberg Helena T. , del Torchio Riccardo , Domanska-Janik Krystyna , Zimmer Jens , Coecke Sandra
Published: July 2009

The aim of our study was to investigate whether a human neural stem cell line derived from umbilical cord blood (HUCB-NSC) can serve as a reliable test model for developmental neurotoxicity (DNT). We assessed the sensitivity of HUCB-NSCs at different developmental stages to a panel of neurotoxic (sodium tellurite, methylmercury chloride, cadmium chloride, chlorpyrifos, and L-glutamate) and non-neurotoxic (acetaminophen, theophylline, and D-glutamate) compounds. In addition, we investigated the effect of some compounds on key neurodevelopmental processes like cell proliferation, apoptotic cell death, and neuronal and glial differentiation. Less differentiated HUCB-NSCs were generally more sensitive to neurotoxicants, with the notable exception of L-glutamate, which showed a higher toxicity to later stages. The relative potencies of the compounds were: cadmium chloride > methylmercury chloride ≫ chlorpyrifos ≫ L-glutamate. Fifty nanomolar methylmercury chloride (MeHgCl) inhibited proliferation and induced apoptosis in early-stage cells. At the differentiated stage, 1 μM MeHgCl induced selective loss of S100β-expressing astrocytic cells. One millimolar L-glutamate did not influence the early stages of HUCB-NSC development, but it affected late stages of neuronal differentiation. A valuable system for in vitro DNT assessment should be able to discriminate between neurotoxic and non-neurotoxic compounds and show different susceptibilities to chemicals according to developmental stage and cell lineage. Although not exhaustive, this work shows that the HUCB-NSC model fulfils these criteria and may serve as a human in vitro model for DNT priority setting.
TWIST Family of Basic Helix-Loop-Helix Transcription Factors Mediate Human Mesenchymal Stem Cell Growth and Commitment
Authors: Isenmann Sandra , Arthur Agnieszka , Zannettino Andrew CW , Turner Jenna L. , Shi Songtao , Glackin Carlotta A. , Gronthos Stan
Published: July 2009

The TWIST family of basic helix-loop-helix transcription factors, Twist-1 and Dermo-1 are known mediators of mesodermal tissue development and contribute to correct patterning of the skeleton. In this study, we demonstrate that freshly purified human bone marrow-derived mesenchymal stromal/stem cells (MSC) express high levels of Twist-1 and Dermo-1 which are downregulated following ex vivo expansion. Enforced expression of Twist-1 or Dermo-1 in human MSC cultures increased expression of the MSC marker, STRO-1, and the early osteogenic transcription factors, Runx2 and Msx2. Conversely, overexpression of Twist-1 and Dermo-1 was associated with a decrease in the gene expression of osteoblast-associated markers, bone morphogenic protein-2, bone sialoprotein, osteopontin, alkaline phosphatase and osteocalcin. High expressing Twist-1 or Dermo-1 MSC lines exhibited an enhanced proliferative potential of approximately 2.5-fold compared with control MSC populations that were associated with elevated levels of Id-1 and Id-2 gene expression. Functional studies demonstrated that high expressing Twist-1 and Dermo-1 MSC displayed a decreased capacity for osteo/chondrogenic differentiation and an enhanced capacity to undergo adipogenesis. These findings implicate the TWIST gene family members as potential mediators of MSC self-renewal and lineage commitment in postnatal skeletal tissues by exerting their effects on genes involved in the early stages of bone development.
Doppler and gray‐scale sonographic classification of adnexal torsion
Authors: Auslender R. , Shen O. , Kaufman Y. , Goldberg Y. , Bardicef M. , Lissak A. , Lavie O.
Published: July 2009

Objective

To propose, in cases with coiling of the ovarian vessels, a classification of severity of torsion based on Doppler and gray‐scale ultrasound findings and to suggest a treatment strategy for each situation.

Methods

Seventeen patients were examined in a gynecological emergency room between December 1995 and February 2003 due to suspected adnexal torsion. Doppler and gray‐scale ultrasound were used to visualize coiling of the ovarian blood vessels. Intraovarian flow was assessed by spectral Doppler and on this basis, along with the patient's clinical condition, the decision was made as to whether surgery was necessary. Findings on surgery were recorded.

Results

All 17 patients showed coiling of the ovarian vessels. Nine had arterial and venous blood flow within the ovary and ultrasound and surgical findings usually demonstrated normal sized or mildly enlarged ovaries. Five had only arterial blood flow within the ovary and surgery usually revealed enlarged ovaries with normal color or mild discoloration. Three had neither arterial nor venous blood flow within the ovary, with vessel coiling evident only on gray‐scale and not on Doppler examination, and surgical findings included signs of ovarian ischemia or necrosis.

Conclusion

In cases of coiling of the ovarian vessels, Doppler flow analysis of the ovary can help differentiate between ischemic adnexal torsion and coiling of the ovarian blood vessels without strangulation, aiding in the choice of treatment. According to type of blood flow seen on Doppler examination, we suggest the following classification of severity of adnexal torsion and treatment strategy: Class 1, coiling with arterial and venous ovarian blood flow; a conservative approach may be considered if the clinical condition permits; Class 2, coiling with arterial ovarian flow but no venous flow; surgical intervention is required; and Class 3, true strangulation, with no ovarian blood flow; urgent surgical intervention is required. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Stability investigation of an airfoil section with active flap control
Authors: Bergami Leonardo , Gaunaa Mac
Published: July 2009

This work presents a method to determine flutter and divergence instability limits for a two‐dimensional (2‐D) airfoil section fitted with an actively controlled trailing edge flap. This flap consists of a deformable trailing edge, which deformation is governed by control algorithms based on measurements of either heave displacement, local angle of attack or aerodynamic pressure difference measured over the airfoil. The purpose of the controlled deformable flap is to reduce fluctuations in the aerodynamic forces on the airfoil, which, according to recent studies, have a significant potential for fatigue load alleviation. The structural model of the 2‐D airfoil section contains three degrees of freedom: heave translation, pitch rotation and flap deflection. A potential flow model provides the aerodynamic forces and their distribution. The unsteady aerodynamics are described using an indicial function approximation. Stability of the full aeroservoelastic system is determined through eigenvalue analysis by state–space formulation of the indicial approximation. Validation is carried out against an implementation of the recursive method by Theodorsen and Garrick for ‘flexure–torsion–aileron’ flutter. The implemented stability tool is then applied to an airfoil section representative of a wind turbine blade with active flap control. It is thereby observed that the airfoil stability limits are significantly modified by the presence of the flap, and they depend on several parameters: flap structural characteristics, type of control, control gain factors and time lag. Copyright © 2009 John Wiley & Sons, Ltd.
Constitutional Isomerism of BiW6Cl15: (BiCl)[W6Cl14] and (BiCl2)[W6Cl13]
Authors: Ströbele Markus , Meyer H.‐Jürgen
Published: July 2009

The compound (BiCl)[W6Cl14] was previously characterized as a product of the reduction of tungsten hexachloride with elemental bismuth. Another modification of BiW6Cl15 is now presented as (BiCl2)[W6Cl13], based on the results of an X‐ray single crystal structure determination (space group P21/c, a = 1354.3(2) pm, b = 1234.4(2) pm, c = 1538.9(2) pm, and β = 118.76(1) °). The structure of (BiCl2)[W6Cl13] contains chains of [(W6Cl8i)Cl4aCl2/2a–a]– clusters bridged by chlorine atoms. The (BiCl2)+ counterion exhibits two short Bi–Cl distances of 244.1(4) and 245.9(3) pm, respectively.
Configurational variations for the primal and dual problem in elasticity
Authors: Materna D. , Barthold F.‐J.
Published: July 2009

This contribution is concerned with variational methods and configurational variations for the primal and the dual problem in elasticity. The derivations of variational balance laws are based on energy minimization principles for the primal and the dual problem. Variations of the energy of the primal problem with respect to configurational changes lead to the primal material residual. We introduce an energy functional of the dual problem and we investigate configurational variations for this energy, which yield a novel material residual of the dual problem. Furthermore, we propose variational sensitivity relations for the primal and the dual solution due to configurational variations. The explicit formulations of the residuals and the sensitivity relations are derived for a hyperelastic material.
Zostera marina population genetics in Barnegat Bay, New Jersey, and implications for grass bed restoration
Authors: Campanella James Joseph , Bologna Paul A. X. , Smith Stephanie M. , Rosenzweig Eric B. , Smalley John V.
Published: July 2009

Within Barnegat Bay, New Jersey, Zostera marina populations have declined by 62% over the last 20 years, and restoration efforts have met with mixed success. We have completed a microsatellite‐based genetic investigation of eight populations of Z.marina within Barnegat Bay to determine whether the genetic stock origins of the plants used in management projects may affect restoration success. Additionally, we assessed the genetic diversity of Z. marina in Barnegat Bay to better understand its population structure. Clonal diversity ranged from 0.70 to 0.95 for the populations studied. Individually, Barnegat Bay populations are not genetically diverse, and there is also little divergence among populations. The Atlantic populations had mean Hobs values (0.20–0.34) that were far lower than the Hexp values (0.69–0.83). Also, the FIS values in all of the eastern populations indicate a surfeit of homozygotes over heterozygotes, suggesting a low degree of outcrossing in the Barnegat Bay populations. Six of the ten populations studied (Ham Island, Manahawkin Bay, Shelter Island, Marsh Elder, Harvey Cedar Sedge, and Long Island) show evidence of historical bottlenecks. Mean estimated FST values would suggest that most alleles are undergoing moderate genetic differentiation, with values that range from 0.06 to 0.13. Oyster Creek and Sedge Island demonstrate the largest estimated effective population sizes and may be the most appropriate populations for use in future eelgrass restoration projects.
Structure of Brazilian Atlantic forests with occurrence of the woolly spider monkey (Brachyteles hypoxanthus)
Authors: da Silva Júnior Wilson Marcelo , de Melo Fabiano Rodrigues , Moreira Leandro Santana , Barbosa Elaine Ferreira , Meira‐Neto João Augusto Alves
Published: July 2009

This work examines patches of Atlantic forests in Minas Gerais State where woolly spider monkeys (Brachyteleshypoxanthus) are inhabitants in order to understand the effects of forest structure, diversity, and succession inB.hypoxanthusabundance. This study was carried out in three reserves: Rio Doce State Park (PERD), Mata do Sossego (Sossego), and Serra do Brigadeiro State Park (PESB). Structural studies were carried out by means of point‐centered quarter samples in areas used by woolly spider monkeys. Evenness was lower in PERD than in the other two communities. By means of successional functional groups analysis and diametric structure, the PERD forest sample was shown to be in the later, and PESB forest sample in the earlier, stages of secondary succession. We found that tree species evenness and structural traits driven by succession were important factors in determining spider monkey abundance patterns. The PERD forest sample had lower evenness and had lower density of woolly spider monkeys than the Sossego forest sample. The lowest density of these primates was in the PESB forest sample, the earlier successional stage of secondary succession of this study.
Mesomorphic Lamella Rolling of Au in Vacuum
Authors: Huang Chang-Ning , Chen Shuei-Yuan , Shen Pouyan
Published: July 2009

Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241–0.192 nm) and the nearest neighbor distance (ca. 0.74–0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458–0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon–hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration.
Predictive bioinformatic identification of minor receptor group human rhinoviruses
Authors: Weber Christoph , Pickl-Herk Angela , Khan Abdul Ghafoor , Strauss Sascha , Carugo Oliviero , Blaas Dieter
Published: July 2009

Major group HRVs bind intercellular adhesion molecule 1 and minor group HRVs bind members of the low‐density lipoprotein receptor (LDLR) family for cell entry. Whereas the former share common sequence motives in their viral capsid proteins (VPs), in the latter only a lysine residue within the binding epitope in VP1 is conserved; this lysine is also present in “K‐type” major group HRVs that fail to use LDLR for infection. By using the available sequences three‐dimensional models of VP1 of all HRVs were built and binding energies, with respect to module 3 of the very‐low‐density lipoprotein receptor, were calculated. Based on the predicted affinities K‐type HRVs and minor group HRVs were correctly classified.
GROUNDNUT YIELD RESPONSE AND ECONOMIC BENEFITS OF FUNGICIDE AND PHOSPHORUS APPLICATION IN FARMER-MANAGED TRIALS IN NORTHERN GHANA
Authors: NAAB J. B. , SEINI S. S. , GYASI K. O. , MAHAMA G. Y. , PRASAD P. V. V. , BOOTE K. J. , JONES J. W.
Published: July 2009

Prior on-station research showed that sowing dates, sowing density and applications of fungicide and phosphorus (P) increased groundnut (Arachis hypogaea) pod yield by 60–80%. Farmer-managed trials were conducted in the Wa district of the Upper West Region of Ghana from 2004 to 2007 to test the yield response to sowing density, fungicide and P and to assess economic returns of these technologies to farmers. Treatments included: an early maturing groundnut cultivar, Chinese, sown at farmers' density (5–8 plant m−2) without fungicide and without P application (T1, control), with fungicide sprays alone (T2), or with fungicide and P application (T3), cultivar Chinese sown at recommended (higher) density (20 plant m−2) with fungicide and P application (T4), and a full season cultivar, Manipinter, with fungicide and P application (T5). Soil fertility, sowing density, days from sowing to first weeding, incidence and severity of leaf-spot disease and plant population at final harvest were recorded. Relative to farmers' practice, pod yield of cultivar Chinese was significantly increased by 80% with fungicide sprays alone, 108% with fungicide and P application, and 113% with fungicide and P application at higher sowing density. Cultivar Manipinter treated with fungicide and P gave 107% increase in pod yield relative to farmers' practice. Correlation and stepwise regression analyses suggested that major determinants of groundnut pod yield in farmers' fields were plant density, leaf-spot disease and P availability. The increase in yield with fungicide and P application translated into a 4–5-fold increase in gross margin for farmers in the region. Returns to labour and labour productivity were doubled with combined use of fungicide and P fertilizer.
Pressure-driven flow in a two-dimensional channel with porous walls
Authors: ZHANG QUAN , PROSPERETTI ANDREA
Published: July 2009

The finite-Reynolds-number two-dimensional flow in a channel bounded by a porous medium is studied numerically. The medium is modelled by aligned cylinders in a square or staggered arrangement. Detailed results on the flow structure and slip coefficient are reported. The hydrodynamic force and couple acting on the cylinder layer bounding the porous medium are also evaluated as a function of the Reynolds number. In particular, it is shown that, at finite Reynolds numbers, a lift force acts on the bodies, which may be significant for the mobilization of bottom sediments.