bluuebunny/crossref_metadata_2025 huggingface dataset:
Arterial spin labeling at ultra‐high field: All that glitters is not gold
Authors: Teeuwisse Wouter M. , Webb Andrew G. , van Osch Matthias J. P.
Published: February 2010

In the past decade, MRI perfusion imaging has become increasingly important in the radiological clinic. Herein, arterial spin labeling (ASL) represents a truly noninvasive method for assessment of hemodynamic changes. Recently, whole body scanners that operate at a field strength of 7 Tesla or above have become available, carrying the promise of higher signal to noise ratio. In this article, we discuss the basic ASL methods that are available today and the problems that may be encountered when implementing ASL on a high field scanner. Particularly, B0 and B1 field inhomogeneities and fluctuations in precession frequency due to respiration were measured at the level of the brain feeding arteries. The effect of these disturbances on ASL is being discussed as are other issues such as specific absorption rate and relaxation rates. It can be concluded that implementation of ASL on MRI systems with high field strength is not trivial, although the feasibility of ASL measurements has been demonstrated at 7 Tesla. Further improvements can be expected, for example by the use of local labeling coils and improved shimming and preparation methods. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 62–70, 2010
Challenges for molecular neuroimaging with MRI
Authors: Lelyveld Victor S. , Atanasijevic Tatjana , Jasanoff Alan
Published: February 2010

Magnetic resonance (MRI)‐based molecular imaging methods are beginning to have impact in neuroscience. A growing number of molecular imaging agents have been synthesized and tested in vitro, but so far relatively few have been validated in the brains of live animals. Here, we discuss key challenges associated with expanding the repertoire of successful molecular neuroimaging approaches. The difficulty of delivering agents past the blood‐brain barrier (BBB) is a particular obstacle to molecular imaging in the central nervous system. We review established and emerging techniques for trans‐BBB delivery, including intracranial infusion, BBB disruption, and transporter‐related methods. Improving the sensitivity with which MRI‐based molecular agents can be detected is a second major challenge. Better sensitivity would in turn reduce the requirements for delivery and alleviate potential side effects. We discuss recent efforts to enhance relaxivity of conventional longitudinal relaxation time (T1) and transverse relaxation time (T2) MRI contrast agents, as well as strategies that involve amplifying molecular signals or reducing endogenous background influences. With ongoing refinement of imaging approaches and brain delivery methods, MRI‐based techniques for molecular‐level neuroscientific investigation will fall increasingly within reach. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 71–79, 2010
Study of white matter anatomy and 3D tract reconstruction by diffusion tensor imaging
Authors: Faria Andreia V. , Oishi Kenichi , Mori Susumu
Published: February 2010

“Diffusion Tensor Imaging” (DTI) has the unique capability to represent the macroscopic white matter architecture. Based on DTI, tractography is able to render 3D trajectories of tracts. There are no other technique that can produce equivalent anatomical information, and, thus, tractography is a powerful method to investigate human brain anatomy. Here, we present an overview of the principles, advantages, shortcomings and possibilities of these methods. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 51–56, 2010
Cytotoxicity and genotoxicity induced by aflatoxin B1, ochratoxin A, and their combination in cultured Vero cells
Authors: Golli‐Bennour Emna El , Kouidhi Bochra , Bouslimi Amel , Abid‐Essefi Salwa , Hassen Wafa , Bacha Hassen
Published: February 2010

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are important food‐borne mycotoxins that have been implicated in human health. In this study, independent and combinative toxicities of AFB1 and OTA were tested in cultured monkey kidney Vero cells. The experiments reported here were conducted to evaluate the effect of these toxins on cell viability followed by the determination of cell death pathways, using the quantification of DNA fragmentation and the expression of p53 and bcl‐2 protein levels. Our results showed that AFB1 and OTA caused a marked decrease of cell viability in a dose‐dependent manner. Under the same conditions, these mycotoxins increased fragmented DNA levels. In addition, p53 was activated in response to DNA damage and the expression of the antiapoptotic factor bcl‐2 decreased significantly. According to these data, AFB1 and OTA seemed to be involved in an apoptotic process. Moreover, combined AFB1 and OTA induced all the toxicities observed with the mycotoxins separately. Therefore, this combination was classified as an additive response of the two mycotoxins. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:42–50, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20310
Establishing effective simulation protocols for β‐ and α/β‐peptides. III. Molecular mechanical model for acyclic β‐amino acids
Authors: Zhu Xiao , Koenig Peter , Hoffmann Michael , Yethiraj Arun , Cui Qiang
Published: February 2010

All‐atom molecular mechanics (MM) force field parameters are developed for the backbone of acyclic β‐amino acid using an improved version of the multiobjective evolutionary algorithm (MOEA). The MM model is benchmarked using β3‐homo‐Alanine (β3‐hAla) diamide in water with SCC‐DFTB/MM simulations as the reference. Satisfactory agreements are found between the MM and SCC‐DFTB/MM results regarding the distribution of key dihedral angles for the β3‐hAla diamide in water. The MM model is further applied to a β‐hepta‐peptide in methanol solution. The calculated NOE values and 3J coupling constants averaged over different trajectories are consistent with experimental data. By contrast, simulations using parameters directly transferred from the CHARMM22 force field for proteins lead to much worse agreement, which highlights the importance of careful parameterization for non‐natural peptides, for which the improved MOEA is particularly useful. Finally, as an initial application of the new force field parameters, the behaviors of a short random copolymer consisting of β amino acids in bulk solution and membrane/water interface are studied using a generalized Born implicit solvent model (GBSW). Results for four selected sequences show that segregation of hydrophobic and cationic groups occur easily at the membrane/solution interface for all sequences. The sequence that features alternating short blocks exhibits signs of lower stability at the interface compared to other sequences. These results confirm the hypothesis in recent experimental studies that β‐amino‐acid based random copolymers can develop a high degree of amphiphilicity without regular three‐dimensional structure. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
Partitions of the 8‐dimensional vector space over GF(2)
Authors: El‐Zanati S. , Heden O. , Seelinger G. , Sissokho P. , Spence L. , Eynden C. Vanden
Published: February 2010

Let V = V(n, q) denote the vector space of dimension n over GF(q). A set of subspaces of V is called a partition of V if every nonzero vector in V is contained in exactly one subspace of V. Given a partition 𝒫 of V with exactly ai subspaces of dimension i for 1≤i≤n, we have , and we call the n‐tuple (an, an − 1, …, a1) the type of 𝒫. In this article we identify all 8‐tuples (a8, a7, …, a2, 0) that are the types of partitions of V(8, 2). © 2010 Wiley Periodicals, Inc. J Combin Designs 18: 462–474, 2010
Some rigid Steiner 5‐designs
Authors: Grannell M. J.
Published: February 2010

Hitherto, all known non‐trivial Steiner systemsS(5,k, v) have, as a group of automorphisms, eitherPSL(2,v−1) orPGL(2, (v−2)/2) ×C2. In this article, systemsS(5, 6, 72),S(5, 6, 84) andS(5, 6, 108) are constructed that have only the trivial automorphism group. © 2010 Wiley Periodicals, Inc. J Combin Designs 18:392–400, 2010
An unusual cause of acute abdominal pain in a child: An inverted meckel diverticulum: Report of a case
Authors: Yigiter Murat , Kıyıcı Halil , Yucesan Selçuk , Hicsonmez Akgün
Published: February 2010

Inverted Meckel diverticulum has been reported as a lead point for intussusception in children. However all cases of isolated inversion of a Meckel diverticulum have involved adults in whom the diagnosis was clinically unexpected. We describe the sonographic appearance of isolated inversion of Meckel diverticulum in a 3‐year‐old boy with acute abdominal symptoms. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound, 2010
The quest for logia psyche in business leadership: An empirical study of cognitive moral development in construction industry dyads
Authors: Reischl James N. , Cavico Frank J. , Mujtaba Bahaudin G. , Pellet Pedro F.
Published: February 2010

This research study examines the ageless human debate of the body versus the soul, testing leadership in the industry of building constructors. Based on Kohlbergian theory of cognitive moral development, the multidisciplinary literature review advances the proposition that moral development proceeds in waves of egoism, leading to altruism that is couched in power—“the apple of the eye.” The results from respondents of the Iowa Architects Institute of America (n = 93) indicated that, despite their higher education and aesthetic interests, the sample of architects ranked low on moral maturity level compared to the average of the Defining Issues Test data bank as a whole. Principled scores were 36.4 for architects and 39.1 for the data bank. This research also compared the moral maturity of intra‐industry groups in marketing dyads consisting of architects, contractors, and suppliers using analysis of variance. Again, it was expected that architects with higher education and aesthetic interests would rank highest. Findings of post hoc comparisons revealed no significant difference in moral maturity level between architects and contractors engrossed in the same power paradigm (p = 1.00), yet a significant difference existed between architects and suppliers (p = 0.024). This implication is consistent with the teleological ethical pattern that is prevalent in research studies of salespeople.
Individual differences in implicit theories of leadership ability and self‐efficacy: Predicting responses to stereotype threat
Authors: Burnette Jeni L. , Pollack Jeffrey M. , Hoyt Crystal L.
Published: February 2010

Extending research on implicit theories to the leadership domain, we examined how individual differences in belief about the malleability of leadership ability influenced responses to stereotype threat. The study consisted of two time periods. At time 1, we assessed individual differences in implicit theories of leadership ability and self‐efficacy for leadership. At time 2, we activated a stereotype threat in a high‐stakes environment. Results revealed that women reported lower self‐evaluation after a stereotype threat when they had low self‐efficacy and believed leadership ability to be fixed (entity theory) rather than malleable (incremental theory). Results are discussed in terms of how implicit theories generate a network of allied cognitions and emotions that subsequently predict stable patterns of behavior.
Rapid increase of Nurr1 mRNA expression in limbic and cortical brain structures related to coping with depression‐like behavior in mice
Authors: Rojas Patricia , Joodmardi Eliza , Perlmann Thomas , Ögren Sven Ove
Published: February 2010

The immediate‐early gene Nurr1 is a member of the inducible orphan nuclear receptor family. Nurr1 is essential to the differentiation, maturation, and maintenance of midbrain dopaminergic neurons and is expressed in different brain regions. We have reported that adult mice with reduced Nurr1 expression displayed an increase in immobility response to acute stress. These mice were also deficient in the retention of emotional memory. Thus, Nurr1 expression seems to be relevant to normal cognitive processes. To investigate the response of Nurr1 to a stress stimulus, Nurr1 mRNA expression was examined by in situ hybridization in adult mice using a depression‐like behavior paradigm, the forced swim test. The Nurr1 gene was rapidly and widely up‐regulated throughout the brain, including cortical areas (i.e., prefrontal cortex, primary and secondary visual cortex, primary auditory cortex, and secondary somatosensory cortex), hippocampus (dentate gyrus, CA1, CA2, and CA3), and midbrain (substantia nigra pars compacta and ventral tegmental area) at 30 min and 3 hr after the forced swim test. Dopamine content was reduced in prefrontal cortex and midbrain following swim stress. These results suggest that the increase in Nurr1 expression might be a compensatory mechanism to counteract the changes in forebrain dopamine transmission in coping with acute stress. © 2010 Wiley‐Liss, Inc.
Further screening of Aspergillus species for occurrence of lectins and their partial characterization
Authors: Singh Ram Sarup , Bhari Ranjeeta , Rai Jyoti
Published: February 2010

Fifteen species of Aspergillus were screened for occurrence of lectins. Nine of them (A. sydowii, A. candidus, A. allahabadi, A. terricola, A. ficuum, A. sparsus, A. carneus, A. pulvinus and A. aculeatus) were found to possess lectin activity. None of the species elaborated lectin in culture supernatant. All the lectins agglutinated rat, pig and rabbit erythrocytes. A. sydowii, A. candidus, A. allahabadi, A. terricola, A. ficuum, A. sparsus, A. carneus and A. aculeatus lectins agglutinated all human type erythrocytes equally, while A. pulvinus lectin specifically agglutinated human type A and O erythrocytes. Neuraminidase and protease treatment to erythrocytes substantially augmented lectin titres manyfold. Lectins showed specificity to mucin and asialofetuin and all of them were specific to L‐arabinose except that of A. carneus. Lectins from A. sydowii, A. ficuum, A. sparsus and A. carneus displayed remarkable specificities to D‐xylose. Maximum lectin activity was expressed by 11 day old cultures of A. sydowii (titre 32), A. ficuum (titre 64) and A. sparsus (titre 1024). Lectins from A. aculeatus, A. candidus and A. terricola were expressed by 7–10 days, 6–9 days and 5–11 days old cultures, respectively. A. allahabadi cultures exhibited maximum lectin activity (titre 32) after 8–10 days of cultivation. A. carneus and A. pulvinus expressed optimal titres of 32 and 8, respectively on the 9th day. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of medium and process parameters for the production of lipase from an oil‐tolerant Aspergillus sp. (RBD‐01)
Authors: Aulakh Satnam Singh , Prakash Ranjana
Published: February 2010

Extracellular lipase production by Aspergillus sp. (RBD‐01) was monitored by modulating pH of the growth medium, ambient temperature for growth, source of nitrogen and percentage of carbon (virgin cottonseed oil). This strain was observed to be viable and produces lipase even up to 50% oil as a main carbon source. Maximum lipase activity of 21.8 U/ml was obtained with 50% (v/v) oil acting as the main carbon source and peptone (0.5% w/v) as nitrogen source. The optimum pH and temperature for enzymatic activity were observed to be 7.5 and 35 °C, respectively. The observations are of significance due to limited reports on use of 50% of oil as the main carbon source while obtaining significant lipase activity of 21.8 U/ml. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of wastewater application on saturated hydraulic conductivity of different soil textures
Authors: Reza Sepaskhah Ali , Sokoot Masoud
Published: February 2010

As metropolitan areas expand, the municipal and industrial uses of freshwater increase. Therefore, water resources for irrigation become limited and wastewater reuse for irrigation becomes a good alternative. For this purpose, the effects of suspended solids in wastewater on the soil physical properties, i.e., saturated hydraulic conductivity, Ks, have to be considered. The objectives of this research were to study the effects of applying freshwater and differently treated wastewater on Ks in the surface and subsurface layers of sandy‐loam, loam, and clay‐loam soils. This effect was studied by investigating the ratio of Ks for wastewater to Ks for fresh water in soil surface as Kr1 and in soil subsurface as Kr2. The results showed that the application of freshwater did not reduce the Kr1 considerably. However, the reduction in Kr1 mainly occurred in soil depth of 0–50 mm due to the application of wastewater. This effect is more pronounced in clay‐loam soil than in loam and sandy‐loam soils. It is concluded that application of wastewater with TSS (total suspended solid) of ≥ 40 mg L–1 resulted in Kr1 reduction of >50% in different soil textures. However, the Kr2 reduction at soil depth of 100–300 mm is not considerable by application of wastewater for different soil textures. Further, it is concluded that less purified wastewater can be used in light‐texture soils resulting in less reduction in Kr1. Empirical models were developed for predicting the value of Kr1 as a function of amounts of wastewater application and TSS for different soil textures that can be used in management of wastewater application for preventing deterioration of soil hydraulic conductivity.
Does the source of nitrogen affect the response of subterranean clover to prolonged root hypoxia?
Authors: Horchani Faouzi , Hajri Rim , Khayati Holmi , Brouquisse Renaud , Aschi‐Smiti Samira
Published: February 2010

Nitrogen (N) is taken up by most plant species in the form of nitrate (NO$ _3^- $) or ammonium (NH$ _4^+ $). The plant response to continuous ammonium nutrition is species‐dependent. In this study, the effects of the source of N nutrition (NO$ _3^- $, NH$ _4^+ $, or the mixture of NO$ _3^- $ and NH$ _4^+ $) on the response of clover (Trifolium subterraneum L. cv. 45C) plants to prolonged root hypoxia was studied. Under aerobic conditions, plant growth was strongly depressed by NH$ _4^+ $, compared to NO$ _3^- $ or mixed N nutrition, as indicated by the significant decrease in root and shoot‐dry‐matter production (DW), root and shoot water contents (WC), leaf chlorophyll concentration, and chlorophyll fluorescence parameters (F0, Fv/Fm). However, the N source had no effect on chlorophyll a–to–chlorophyll b ratio. Under hypoxic conditions, the negative effects of root hypoxia on plant‐growth parameters (DW and WC), leaf chlorophyll concentration, and chlorophyll fluorescence parameters were alleviated by NH$ _4^+ $ rather than NO$ _3^- $ supply. Concomitantly, shoot DW–to–root DW ratio, and root and leaf NH$ _4^+ $ concentrations were significantly decreased, whereas root and leaf carbohydrate concentrations, glutamine synthetase activities, and protein concentrations were remarkably increased. The present data reveal that the N source (NO$ _3^- $ or NH$ _4^+ $) is a major factor affecting clover responses to hypoxic stress, with plants being more tolerant when NH$ _4^+ $ is the N form used. The different sensitivity is discussed in terms of a competition for energy between nitrogen assimilation and plant growth.
Characterization of archeological glasses by micro‐Raman spectroscopy
Authors: Cesaratto A. , Sichel P. , Bersani D. , Lottici P. P. , Montenero A. , Salvioli‐Mariani E. , Catarsi M.
Published: February 2010

The method based on the deconvolution of the Raman spectra of glasses, proposed for the investigation of glazed ceramics by Colomban, is applied to archeological samples of glass of two different origins in an attempt to characterize the glass composition and the fictive temperature using a contactless, nondestructive spectroscopic technique. The samples investigated are glassy mosaic tesserae of Roman times from Massa Lubrense, Napoli, Italy, and medieval rosary grains found during the excavations in the church of San Martino di Rivosecco, Parma, Italy. The polymerization index, obtained as the ratio of the bending and stretching band amplitudes, suggests firing temperatures not less than 1000–1100 °C for both Roman and medieval glasses. From the wavenumber shift of some stretching bands at about 1050–1100 cm−1, the content of lead was estimated. The medieval samples show a lower Pb content, a result confirmed by elementary energy dispersive X‐ray spectral data. Copyright © 2010 John Wiley & Sons, Ltd.
Citrinin selective molecularly imprinted polymers for SPE
Authors: Guo Bao‐Yuan , Wang Songxue , Ren Baozhong , Li Xin , Qin Fei , Li Jianzhong
Published: February 2010

Molecularly imprinted polymers (MIPs) for citrinin (Cit) with 1‐hydroxy‐2‐naphthoic acid (HNA) as mimic template were prepared and the molecularly imprinted SPE method was developed for the detection of Cit in rice with HPLC. The adsorption properties of HNA and Cit on the MIPs and nonimprinted polymers were investigated. It proved that MIPs showed higher selectivity adsorption to HNA and Cit than nonimprinted polymers were. The recoveries of Cit in rice were in the range of 86.7–97.7%. The spiked rice samples and five rice samples in Beijing market were detected using molecularly imprinted SPE method and satisfied results were obtained as discussed in this article.
Separation of peptide diastereomers using CEC and a hydrophobic monolithic column
Authors: Ludewig Ronny , Dong Jing , Zou Hanfa , Scriba Gerhard K. E.
Published: February 2010

A neutral hydrophobic monolith prepared by radical in situ copolymerization of lauryl methacrylate and ethylene dimethacylate has been evaluated for the CEC separation of diastereomers of small peptides using acidic mobile phases containing ACN as organic modifier. Using an acidic mobile phase, the peptides migrated due to their own electrophoretic mobility. Hydrophobic interactions with the stationary phase contributed to the separation. Peptide mobility and resolution increased with increasing the ACN content. Retention times increased with the pH of the mobile phase. Peak resolution increased with buffer pH and concentration. Di‐ and tripeptides composed only of L‐configured amino acids migrated faster than peptides containing D‐amino acids. A mixture of isomeric Asp tripeptides that could not be completely resolved by either CZE or HPLC as well as the 24mer peptides tetracosactide and 16[D‐Lys]‐tetracosactide could also be separated by CEC on the hydrophobic monolith.
Behavior of Nematic Bipolar Droplets in PDLC Films: An Optimization Study
Authors: Akbarzadeh Vajiheh , Lohi Ali , Chan Philip K. , Upreti Simant R.
Published: February 2010

The effect of nematic droplet shape, elastic constant ratio of liquid crystals, and external field strength on the performance of PDLC films is examined. The finite‐difference method is used to model a single droplet with external field applied parallel to the droplet axis of symmetry. Genetic algorithm is employed to determine the optimal (i) aspect ratio, (ii) elastic constant ratio, and (iii) external field strength, which minimize the response and relaxation times for the droplet reorientation as well as the energy requirement.

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5,7,3′‐trihydroxy‐3,4′‐dimethoxyflavone‐induced cell death in human Leukemia cells is dependent on caspases and activates the MAPK pathway
Authors: Torres Fernando , Quintana José , Estévez Francisco
Published: February 2010

Flavonoids are polyphenolic compounds which display a vast array of biological activities and are promising anticancer agents. In this study we investigated the effect of 5,7,3′‐trihydroxy‐3,4′‐dimethoxyflavone (THDF) on viability of nine human tumor cell lines and found that it was highly cytotoxic against leukemia cells. THDF induced G2–M phase cell‐cycle arrest and apoptosis through a caspase‐dependent mechanism involving cytochrome c release, processing of multiple caspases (caspase‐3, ‐6, ‐7, and ‐9) and cleavage of poly(ADP‐ribose) polymerase. Overexpression of the protective mitochondrial proteins Bcl‐2 and Bcl‐xL conferred partial resistance to THDF‐induced apoptosis. This flavonoid induced the phosphorylation of members of the mitogen‐activated protein kinases (MAPKs) family and cell death was attenuated by inhibition of c‐jun N‐terminal kinases/stress‐activated protein kinases (JNK/SAPK) and of extracellular signal‐regulated kinases (ERK) 1/2. In the present study we report that THDF‐induced cell death is mediated by an intrinsic dependent apoptotic event involving mitochondria and MAPKs, and through a mechanism independent of the generation of reactive oxygen species. The results suggest that THDF could be useful in the development of novel anticancer agents. Mol. Carcinog. © 2010 Wiley‐Liss, Inc.
Self‐rated health status in spinocerebellar ataxia—Results from a European multicenter study
Authors: Schmitz‐Hübsch Tanja , Coudert Mathieu , Giunti Paola , Globas Christoph , Baliko Laszlo , Fancellu Roberto , Mariotti Caterina , Filla Alessandro , Rakowicz Maryla , Charles Perrine , Ribai Pascale , Szymanski Sandra , Infante Jon , van de Warrenburg Bart P.C. , Dürr Alexandra , Timmann Dagmar , Boesch Sylvia , Rola Rafal , Depondt Chantal , Schöls Ludger , Zdzienicka Elszbieta , Kang Jun‐Suk , Ratzka Susanne , Kremer Berry , Schulz Jörg B. , Klopstock Thomas , Melegh Bela , du Montcel Sophie Tezenas , Klockgether Thomas
Published: February 2010

Patient‐based measures of subjective health status are increasingly used as outcome measures in interventional trials. We aimed to determine the variability and predictors of subjective health ratings in a possible target group for future interventions: the spinocerebellar ataxias (SCAs). A consecutive sample of 526 patients with otherwise unexplained progressive ataxia and genetic diagnoses of SCA1 (117), SCA2 (163), SCA3 (139), and SCA6 (107) were enrolled at 18 European referral centers. Subjective health status was assessed with a generic measure of health related quality of life, the EQ‐5D (Euroqol) questionnaire. In addition, we performed a neurological examination and a screening questionnaire for affective disorders (patient health questionnaire). Patient‐reported health status was compromised in patients of all genotypes (EQ‐5D visual analogue scale (EQ‐VAS) mean 61.45 ± 20.8). Specifically, problems were reported in the dimensions of mobility (86.9% of patients), usual activities (68%), pain/discomfort (49.4%), depression/anxiety (46.4%), and self care (38.2%). Multivariate analysis revealed three independent predictors of subjective health status: ataxia severity, extent of noncerebellar involvement, and the presence of depressive syndrome. This model explained 30.5% of EQ‐VAS variance in the whole sample and might be extrapolated to other SCA genotypes. © 2010 Movement Disorder Society
Approximating minimum Steiner point trees in Minkowski planes
Authors: Brazil M. , Ras C. J. , Thomas D. A.
Published: February 2010

Given a set of points, we define a minimum Steiner point tree to be a tree interconnecting these points and possibly some additional points such that the length of every edge is at most 1 and the number of additional points is minimized. We propose using Steiner minimal trees to approximate minimum Steiner point trees. It is shown that in arbitrary metric spaces this gives a performance difference of at most 2n‐ 4, wherenis the number of terminals. We show that this difference is best possible in the Euclidean plane, but not in Minkowski planes with parallelogram unit balls. We also introduce a new canonical form for minimum Steiner point trees in the Euclidean plane; this demonstrates that minimum Steiner point trees are shortest total length trees with a certain discrete‐edge‐length condition. © 2010 Wiley Periodicals, Inc. NETWORKS, 2010
MSHSM – Minimal Standard Heterotic String Models
Authors: Faraggi A.E.
Published: February 2010

An overview of old and new results in studies of the quasi‐realistic free fermionic models is presented, which include the recent discovery of exophobic string vacua and reproduction of the Higgs‐matter splitting mechanism in a corresponding orbifold construction.
Predicting μc‐Si:H crystal orientation from Raman measurement under polarized light
Authors: Agbo S. N. , van Swaaij R. A. C. M. M. , Zeman M. , Sutta P.
Published: February 2010

The determination of the dominant crystal orientation is of great importance in gaining insight into the growth mechanisms of hydrogenated microcrystalline silicon (μc‐Si:H). However, for this purpose most techniques are time‐consuming, expensive and destructive. In this contribution, a new approach is investigated to determine crystal orientation in μc‐Si:H films from Raman spectrum. Raman measurements have been applied under varying polarization angles to a series of samples of varying crystalline volume fraction (fc) covering the transition from amorphous to microcrystalline silicon regime. First, the dependence of the Raman intensity of the 520 cm–1 TO peak on polarization angle is measured on [100], [110], and [111] single‐crystalline silicon wafers. We found distinct patterns for these reference wafers and have used these patterns as a fingerprint for a specific crystal orientation in μc‐Si:H. Subsequently, we measured the Raman intensity of the TO peak as a function of polarisation angle on the μc‐Si:H films and compared the obtained patterns with that of the references. For most of the rf PECVD μc‐Si:H samples we obtained a dominant crystal orientation of [111]. We found that the dominant crystal orientation is independent of the crystalline volume fraction of the μc‐Si:H. The inferred crystal orientation will be compared with XRD results. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of chemical composition of SiOx films on rapid formation of Si nanocrystals induced by thermal plasma jet irradiation
Authors: Okada Tatsuya , Higashi Seiichiro , Kaku Hirotaka , Makihara Katsunori , Furukawa Hirokazu , Hiroshige Yasuo , Miyazaki Seiichi
Published: February 2010

Si nanocrystal floating gate MOS capacitors were formed on p‐Si (100) wafers by thermal plasma jet (TPJ) annealing of SiO2/SiOx /SiO2/Si(100) stacked structure. The chemical composition of SiOx layer was controlled by changing the SiH4, He, and O2 gas flow ratio during plasma enhanced chemical vapour deposition. The MOS capacitors showed clear hysteresis in capacitance‐voltage (CV) characteristics after TPJ annealing. The hysteresis width shows maximum value when initial composition x =1.7, which shows the maximum photoluminescence (PL) intensity. The maximum hysteresis width of 6.8 V was observed with gate voltage swept between 20 and ‐20 V in x = 1.7 sample. The result means 7.4 × 1012 cm‐2 carriers are injected to or emitted from Si nanocrystals. The duration of 1 V shift in flatband voltage was ∼0.1 ms with 20 V pulse, and charged carriers were stably maintained for ∼2 hours. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaSb film growth by liquid phase epitaxy
Authors: García‐Cruz M. L. , Martínez‐Juárez J. , López‐Salazar P. , Díaz G. Juárez
Published: February 2010

Doped GaSb (Gallium Antimonide) films on p‐GaSb substrates have been obtained by means of a low‐cost and fast‐growth method: the liquid phase epitaxy (LPE) technique. The growth temperature was 400 °C, and the growth time was varied between1 and 5 min. Characterization of the films was performed by means of high resolution X‐ray Diffraction, low temperature‐photoluminiscence and current‐voltage curve measurements. The X‐ray diffraction pattern confirms a zincblende‐type crystal structure with a high‐thin peak centred at 30.36°. The PL spectra at 27 K allowed to confirm the band‐gap energy to be 0.8 eV and the I‐V curves presented a PN junction behavior which corresponds to the obtained structured. Metal contacts of Au‐Zn and Au‐Ge were placed to perform electrical characterization (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of electric charge transport in conjugated polymer P3HT: PCBM solar cell with temperature dependent current and capacitance measurements
Authors: Yu Peiqing , Mencaraglia Denis , Darga Arouna , Migan Anne , Rabdbeh Roshanak , Ratier Bernard , Moliton André
Published: February 2010

We investigated quantitatively the electronic transport properties of a bulk heterojunction polymer/fullerene solar cell, based on structure Glass/ITO/P3HT:PCBM/Al. The current‐voltage I‐V characteristics in the intermediate positive bias and temperature regime (0.2 V ≤ V ≤ 1.5 V, 180 K ≤ T ≤ 250 K) can be well fitted by a modified Poole‐Frenkel PF detrapping model. Combining these results with the high frequency capacitance measurements, we could then derive independently the absorber thickness and its dielectric constant. At low temperature (80 K ≤ T ≤ 170 K), the I‐V data can be well accounted for with Space Charge Limited Current (SCLC) regimes. At intermediate positive bias (1 V ≤ V ≤ 2.3 V), the current is dominated by the trapped space charges with an exponential traps distribution, while at high positive bias (2.5 V ≤ V ≤ 4 V), the space charges due to injected free carrier play an important role for the conduction. From the fits to the two different SCLC models, we could then extract the electrically active defects parameters controlling the transport. These parameters were confirmed by space charge capacitance spectroscopy (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polycrystalline Si films with unique microstructures formed from amorphous Si films by non‐thermal equilibrium flash lamp annealing
Authors: Ohdaira Keisuke , Nishikawa Takuya , Shiba Kazuhiro , Takemoto Hiroyuki , Matsumura Hideki
Published: February 2010

Flash lamp annealing (FLA), with millisecond‐order duration, can crystallize amorphous silicon (a‐Si) films a few μm thick on glass substrates, resulting in formation of polycrystalline Si (poly‐Si) films with unprecedented periodic microstructures. The characteristic microstructure, formed spontaneously during crystallization, consists of large‐grain regions, containing relatively large grains more than 100 nm in size, and fine‐grain regions, including only 10‐nm‐sized fine grains. The microstructures results from explosive crystallization (EC), driven by heat generation corresponding to the difference of the enthalpies of meta‐stable a‐Si and stable crystalline Si (c‐Si) states, which realizes lateral crystallization velocity on the order of m/s. The lateral crystallization may stop when the temperature of a‐Si in the vicinity of c‐Si, which is decided by both homogeneous heating from flash irradiation and thermal diffusion from c‐Si, falls below a crystallization temperature. This idea is supported by the experimental fact that a lateral crystallization length decreases with decreasing pulse duration. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydromorphological alteration of a large Mediterranean river: Relative role of high and low flows on the evolution of riparian forests and channel morphology
Authors: Magdaleno Fernando , Fernández J. Anastasio
Published: February 2010

This paper evaluates the causes and effects of the hydrogeomorphological alteration of the central reach of the Ebro River (NE Spain). The Ebro River is one of the largest Mediterranean rivers. In this reach, it develops a meandering planform in a wide floodplain. Geographic Information System (GIS) analyses of historic aerial photographs, analysis of hydrologic data and measurement of various indicators linked to the fluvial morphology and the structure and distribution of the riparian vegetation led to the establishment of the prevailing processes in the dynamics of this river.

Statistical analyses conducted on some of the main components of the flow regime, including floods, droughts and flow duration curves, showed a role for these components in river dynamics. Similarly, a thorough analysis of the evolution of the aforementioned indicators was performed to identify and measure the effects of the hydrological regulation of the river. These indicators were measured in 1927, 1956 and 2003 for a 106 km reach.

The geomorphic dynamics of the Ebro River in its central reach reflect a remarkable tendency for stabilization and rigidification of the channel. The active river corridor has largely been modified, primarily in the second half of the twentieth century. The corridor lost a huge portion of its width and extension, the channel suffered an intense narrowing and the natural mobility of the meander train decayed proportionally. The structure and distribution of the riparian vegetation were completely transformed. The riparian forest lost its original function, behaving as a linear corridor and was notably continuous and very close to the channel thalweg. The vegetation colonized most of the previously active channel, contributing to the loss of the natural dynamics of the river.

The hydrological analyses suggest that the large morphological modification of the river planform and the parallel alteration of the riparian forests are not to be seen as a consequence of a loss of the attributes of natural floods. On the contrary, these extreme hydrological events only generate slight alterations due to river regulation and are not capable of enhancing the aforementioned evolution. Nevertheless, a profound change in the attributes of the low (summer) flows was found. The modification of the low flows was studied through its relationship with the global evolution of the geomorphic indicators and the riparian forest indicators. The results show the relative role played by high and low flows in the evolution of the river dynamics. These results are used to propose a future scenario of ecohydrological management in the central reach of the Ebro River. This scenario is intended to improve its ecological status and recover, at least partially, its natural dynamics. Copyright © 2010 John Wiley & Sons, Ltd.
Inhibition effect of cerium in hybrid sol–gel films on aluminium alloy AA2024
Authors: Paussa L. , Rosero‐Navarro N. C. , Andreatta F. , Castro Y. , Duran A. , Aparicio M. , Fedrizzi L.
Published: February 2010

Aluminium alloys such as AA2024 are susceptible to severe corrosion attack in aggressive solutions (e.g. chlorides). Conversion coatings, like chromate, or rare earth conversion coatings are usually applied in order to improve corrosion behaviour of aluminium alloys. Methacrylate‐based hybrid films deposited with sol–gel technique might be an alternative to conversion coatings. Barrier properties, paint adhesion and possibly self‐healing ability are important aspects for replacement of chromate‐based pre‐treatments. This work evaluates the behaviour of cerium as corrosion inhibitor in methacrylate silane‐based hybrid films containing SiO2 nano‐particles on AA2024. Hybrid films were deposited on aluminium alloy AA2024 by means of dip‐coating technique. Two different types of coating were applied: a non‐inhibited film consisting of two layers (non‐inhibited system) and a similar film doped with cerium nitrate in an intermediate layer (inhibited system). The film thickness was 5 µm for the non‐inhibited system and 8 µm for the inhibited system. Film morphology and composition were investigated by means of GDOES (glow discharge optical emission spectroscopy). Moreover, GDOES qualitative composition profiles were recorded in order to investigate Ce content in the hybrid films as a function of immersion time in 0.05 M NaCl solution. The electrochemical behaviour of the hybrid films was studied in the same electrolyte by means of EIS technique (electrochemical impedance spectroscopy). Electrochemical measurements provide evidence that the inhibited system containing cerium displays recovery of electrochemical properties. This behaviour is not observed for the non‐inhibited coating. GDOES measurements provide evidence that the behaviour of inhibited system can be related to migration of Ce species to the substrate/coating interface. Copyright © 2010 John Wiley & Sons, Ltd.
Structure and deviancy training in after‐school programs
Authors: Rorie Melissa , Gottfredson Denise C. , Cross Amanda , Wilson Denise , Connell Nadine M.
Published: February 2010

Evidence regarding the effectiveness of after‐school programs (ASPs) for reducing problem behaviors is mixed. Unstructured ASPs may increase antisocial behavior by increasing “deviancy training” opportunities, when peers reinforce deviant attitudes and behaviors. This research analyses approximately 3000 five‐minute intervals from 398 observations of activities delivered as part of an ASP in five public middle schools. Analyses of peer and group leader responses to deviant behavior in the context of ASP activities indicated that while peer responses are generally reinforcing, group leaders typically do not respond to deviance. Multi‐level analyses of the association between activity structure and deviant behavior indicate that higher levels of structure in the activity as a whole decrease levels of violence and counternormative behavior. As the level of structure in five‐minute intervals within the activity increases, the level of violent behavior declines, but violent talk (e.g., threats to commit violence) increases. Implications for after‐school programming are discussed.
Unraveling evolutionary constraints: A heterogeneous conservation in dynamics of the titin Ig domains
Authors: Lukman Suryani , Grant Guy H. , Bui Jennifer M.
Published: February 2010

The giant protein titin, which comprises immunoglobulin (Ig) domains, acts as a bidirectional spring in muscle. The unfolding of Ig domains has been extensively studied, but their dynamics under native states have not been well‐characterized. We performed molecular dynamics simulation on a single titin Ig domain and multi‐domains. Mobile regions displaying concerted motions were identified. The dynamics of Ig domains are constrained by evolutionary pressures, in such a way that global dominant motion is conserved, yet different flexibilities within Ig domains and in linkers connecting neighbouring domains were observed. We explain these heterogeneous conserved dynamics in relation to sequence conservation across species and the sequence diversity among neighbouring Ig domains.
The −509 C/T genotype of TGFβ1 might contribute to the pathogenesis of benign airway stenosis
Authors: Rovó László , Széll Márta , Bella Zsolt , Korsós Anita , Kemény Lajos , Jóri József
Published: February 2010

Benign airway stenosis (BAS) is one of the most severe complications of endotracheal intubation. The aim of this pilot study was to compare the frequencies of four polymorphisms of the transforming growth factor (TGF) β1 gene in patients with BAS due to endotracheal intubation (n = 36) and a control group of intensive care patients who had also undergone endotracheal intubation but did not present BAS (n = 30). One of the studied polymorphisms, the −509 C/T, demonstrated a differential genotype distribution between the affected and the control population: the ratio of heterozygous mutants was significantly (P = 0.0116) higher among the control patients. These data suggest a protective function of the frequent heterozygous C/T genotype against BAS; alternatively, the C/C genotype might be a susceptibility factor for BAS (OR 4.5; 95% CI 1.5123–13.3902). Our findings suggest that, besides other iatrogenic factors, a genetic predisposition might contribute to the pathogenesis of BAS.
Impact of pretreatment nasal symptoms on treatment outcome in allergic rhinitis
Authors: Kirtsreesakul Virat , Chansaksung Prichaya , Ruttanaphol Suwalee
Published: February 2010

Objective

The Allergic Rhinitis and its Impact on Asthma (ARIA) classification of allergic rhinitis (AR) is based on the severity and duration of nasal symptoms. Whether nasal symptoms have an impact on treatment outcome is unclear. The aim of this study was to evaluate the correlation between pretreatment nasal symptoms and therapeutic response in AR.

Study Design

Case series with planned data collection.

Setting

Tertiary medical center.

Subjects and Methods

Sixty‐nine AR patients were classified according to ARIA class: mild or moderate‐severe intermittent AR (MIAR or MSIAR) and mild or moderate‐severe persistent AR (MPAR or MSPAR). All patients were treated over 28 days with 220 μg of intranasal triamcinolone acetonide once daily. Nasal symptoms, peak expiratory flow index, and global symptom control were used to evaluate treatment outcome.

Results

At 28 days after treatment, MSPAR patients showed the worst global symptom control, followed by MSIAR, MPAR, and MIAR (mean global symptom controls were 76.5%, 83.8%, 87.7%, and 89.0%, respectively). Pretreatment total nasal symptom score was inversely correlated with global symptom control (ρ = −0.405, P < 0.001), but positively correlated with percent total nasal symptom score and peak expiratory flow index improvements (ρ = 0.271, P = 0.024; and ρ = 0.371, P = 0.002, respectively). Blocked nose had the best inverse correlation with global symptom control (ρ = −0.389, P = 0.001).

Conclusion

A worse treatment outcome despite more clinical improvements during the treatment period in a higher severity score suggests the therapeutic predictive value of pretreatment nasal symptom scoring and the need for more dosing and continuing medication in higher scores, especially in blocked nose.
The future of otolaryngology training threatened: The negative impact of residency training reforms
Authors: Singer Michael C.
Published: February 2010

Resident training regulations developed by the Accreditation Council for Graduate Medical Education (ACGME) in 2003 have limited resident work hours and autonomy. Proposed to improve patient safety and resident education, these regulations have not had their intended effects. They have acted to dilute otolaryngology residents' experiences, thereby weakening their training. The ACGME is currently considering tightening these regulations. By advocating for residency guidelines that are more conducive to the needs of otolaryngology education, otolaryngologists can guarantee continued superlative training for future residents.
Experience with endoscopic dacryocystorhinostomy using four methods
Authors: de Souza Chris , Nissar Jayesh
Published: February 2010

Objective

Evaluation of four methods of endoscopic dacryocystorhinostomy (EDCR) for treating chronic dacryocystitis.

Study Design

Case series with chart review.

Materials and Methods

A total of 1450 patients underwent EDCR for epiphora, chronic dacryocystitis, and blocked nasolacrimal ducts. Relief from epiphora, dacryocystitis, and patency of the fistula for all four techniques was compared. A total of 292 patients underwent incision and drainage, 343 patients had grommets inserted, 258 had silastic lacrimal stents inserted, and 557 had the medial wall of the lacrimal sac (LS) removed. Parameters of success were 1) resolution of epiphora, 2) no further attacks of dacryocystitis, and 3) patency of the new fistula.

Results

Sixty‐five percent failed the incision method, and 68 percent of the patients who underwent the grommet method failed. All 258 patients with lacrimal stents experienced success while the stent remained in situ. Ten patients required removal because the stents created corneal opacities. One required removal because of a foreign body granuloma at the punctum. Only eight (1.4%) patients with removal of the LS failed. On multivariate analysis, female sex (OR = 5.6) was found to be associated with a higher rate of failure. Incision and drainage (OR = 100.1) and grommet insertion (OR = 60.6) were associated with increased risk of failure. Removal of the medial wall of the LS (OR = 0.069) and findings of a clear sac (OR = 0.001) or mucus (OR = 0.204) were associated with success.

Conclusion

The best EDCR results are achieved by stenting or removal of the medial wall of the LS. In our experience, excision of the medial wall of the LS was as successful as insertion of silastic lacrimal intubation stents, without the disadvantage of causing corneal opacities.