bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental links to reduced tropical cyclogenesis over the south‐east Caribbean
Authors: Georgiadis Alexandros P. , Bigg Grant 
Published: November 2006

AbstractTropical cyclone formation over the Caribbean is not evenly distributed across the basin. Previous work identified the south‐western sector as the area that dominates the hurricane activity of the whole basin. The south‐eastern sector, in contrast, exhibits a distinct suppression in cyclogenesis. This study seeks to identify the restricting factors that differentiate the cyclogenesis climatology in the south‐east Caribbean. It is based on statistical analysis of eight environmental variables using principal component analysis. The first three components are examined in detail. The first component, accounting for 31.7% of the variance within the data, differentiates the Caribbean from the rest of the subtropical Atlantic, primarily in terms of an increased thermodynamic potential for cyclogenesis and enhanced atmospheric humidity in the boundary layer. The second component, accounting for 31% of the variance, marks the south‐west Caribbean as the only sub‐region within the area of analysis where the easterlies curve southwards and the relative vorticity is cyclonic. The third component, accounting for 20.3% of the variance, differentiates the South Caribbean from the rest of the Atlantic, indicating it to be a region of increased spatial variation in the intensity of the easterlies and in absolute vorticity. The variance of cyclogenesis within the Caribbean is greatest along the second and third components. Thus, the genesis pattern in the basin is likely associated with the low‐level wind‐field and absolute vorticity. The divergence of the flow, when combined with the vorticity of the wind‐field over the Caribbean, renders the background conditions of the eastern sector less prone to developing disturbances than is the case in the western Caribbean. Copyright © 2006 Royal Meteorological Society
Seismic response of slopes subjected to incident SV wave by an improved boundary element approach
Authors: Gatmiri Behrouz , Nguyen Khoa‐Van , Dehghan Kaveh 
Published: November 2006

AbstractIn this paper, an improved boundary element approach for 2D elastodynamics in time‐domain is presented. This approach consists in the truncation of time integrations, based on the rapid decrease of the fundamental solutions with time. It is shown that an important reduction of the computation time as well as the storage requirement can be achieved. Moreover, for half‐plane problems, the size of boundary element (BE) meshes and the computation time can be significantly reduced. The proposed approach is used to study the seismic response of slopes subjected to incident SV waves. It is found that large amplifications take place on the upper surface close to the slope, while attenuations are produced on the lower surface. The results also show that surface motions become very complex when the incident wavelength is comparable with the size of the slope or when the slope is steep. Copyright © 2006 John Wiley & Sons, Ltd.
Kinetic and mechanistic study of the reactions of aryl chloroformates with quinuclidines
Authors: Castro Enrique A. , Aliaga Margarita , Campodonico Paola R. , Leis J. Ramón , García‐Río Luis , Santos José G. 
Published: November 2006

AbstractThe reactions of quinuclidines with phenyl, 4‐methoxyphenyl, 4‐chlorophenyl, and 4‐nitrophenyl chloroformates (PClF, MOPClF, ClPClF, and NPClF, respectively) in aqueous solution (25 °C, ionic strength 0.2 M KCl) are followed spectrophotometrically and evaluated kinetically. Under amine excess, pseudo‐first‐order rate coefficients (kobsd) are found. Plots of kobsdversus [quinuclidine] are linear, with the pH‐independent slope (kN). The Brønsted‐type plots (log kNvs. pKa of quinuclidinium ions) are linear with slopes (β) of 0.32, 0.34, 0.31, and 0.23 for the reactions of PClF, MOPClF, ClPClF, and NPClF, respectively. The magnitude of the slopes suggests that these mechanisms are stepwise, with the formation of a zwitterionic tetrahedral intermediate (T±) being the rate‐determining step. The sensitivity of log kN to the basicity of the nonleaving group (βnlg) is −0.16. By comparing the reactions under investigation between each other and with similar aminolyses, the following conclusions can be drawn: (i) the mechanisms for the quinuclidinolysis of the four chloroformates studied are stepwise. (ii) The reactivity increases in the sequence MOPClF < PClF < ClPClF < NPClF. (iii) The change of the leaving group from 2,4‐dinitrophenoxide to chloro changes the mechanism from concerted to stepwise. (iv) Quinuclidines are more reactive toward aryl chloroformates than isobasic secondary alicyclic amines. Copyright © 2006 John Wiley & Sons, Ltd.
Lung function in infants and young children with chronic lung disease of infancy: The next steps?
Authors: Stocks Janet , Coates Allan , Bush Andrew 
Published: November 2006

AbstractOver the past year, a series of papers have reviewed the literature concerning assessment and interpretation of lung function in infants and young children with chronic lung disease of infancy. This manuscript, which represents the final paper in that series, summarizes the findings to date and highlights key areas for future research. Despite the huge literature in this field, interpretation of results and their use in guiding clinical management are still limited by difficulties in ‘normalizing data’ according to body size and maturation and selection of appropriate control groups. Furthermore, sensitive tests that more closely reflect the underlying pathophysiology of ‘new’ bronchopulmonary dysplasia, together with simple and reliable methods of assessing lung maturity at birth and true oxygen requirements at specified time points are urgently required. Research in this field is also challenged by the need to separate the independent effects of genetic predisposition, gene–environment interactions, preterm delivery, neonatal respiratory disorders and various treatment strategies on the growing lung. The extent to which disruption of lung growth following premature exposure to the extra‐uterine environment leads to an earlier or more aggravated decline in respiratory function in later adult life remains to be elucidated. Whatever its origin, given the increasing survival of smaller and more immature infants, the long term sequelae of neonatal lung disease, are likely to continue to change, requiring ongoing, carefully designed longitudinal studies. Future research strategies need to encompass a multicenter, multi‐disciplinary, collaborative approach with closer links between clinicians and basic scientists, to ensure that the most relevant research questions are addressed using appropriate methodology and that findings are implemented into clinical practice in a more timely fashion. Pediatr Pulmonol. 2007; 42:3–9. © 2006 Wiley‐Liss, Inc.
Managing isolated subglottic juvenile xanthogranuloma without tracheostomy: Case report and review of literature
Authors: Somorai Marta , Goldstein Nira A. , Alexis Richard , Giusti Robert J. 
Published: November 2006

AbstractJuvenile Xanthogranuloma (JXG) is a dendritic cell related histiocytic disorder which usually presents in the first year of life as a solitary cutaneous granuloma. Isolated presentation in the upper airway is very rare but can result in severe respiratory distress, especially in young children. We present the case of a 5‐month‐old male with an isolated subglottic JXG lesion. Endoscopic excision provided symptomatic relief and avoided the need for tracheostomy. The lesion has completely resolved 17 months later. Surgical excision without tracheostomy was the treatment of choice in two of the four additional cases of upper airway JXG presented in the literature. JXG has an excellent prognosis with spontaneous regression over time. Histology alone is frequently inadequate to differentiate JXG from the more common Langerhans Cell Histiocytosis (LCH), which carries a much less favorable prognosis. The evolving field of immunohistochemistry provides an essential tool to establish the correct diagnosis. The typical phenotype of JXG is Factor XIIIa+/Fascin+/CD68+/CD163+/CD14+/CD1a−/S100−. Pediatr Pulmonol. 2007; 42:181–185. © 2006 Wiley‐Liss, Inc.
The repeatability of submaximal endurance exercise testing in cystic fibrosis
Authors: Barry Sinead C. , Gallagher Charles G. 
Published: November 2006

AbstractSubmaximal endurance cycle ergometer exercise tests are used to measure the efficacy of an exercise intervention, but the repeatability of these tests in patients with cystic fibrosis (CF) has not been established. The purpose of this study was to examine the repeatability of submaximal endurance testing in stable CF. Fifteen adults with CF underwent two submaximal endurance tests carried out over a 7‐day period. A subset of six subjects returned 28 days later for a third submaximal endurance test. Workload was set at 80% of maximum workload and exercise was performed to exhaustion. Oxygen consumption, minute ventilation, tidal volume, carbon dioxide output, respiratory rate, heart rate, and oxygen saturation were measured at rest, at end exercise and at four matched times during the submaximal endurance tests (20, 40, 60, and 80% of exercise duration calculated from the first endurance test). Submaximal endurance test time was highly repeatable with no significant learning effect identified on multiple testing. Submaximal endurance exercise time demonstrated a variability of 5.7% which is consistent with high levels of repeatability. Metabolic, ventilatory and cardiac variables were all also highly reproducible between test days. Submaximal endurance testing is repeatable in stable CF, confirming that submaximal endurance tests are a reliable tool for assessment of therapeutic benefit in patients with CF. Pediatr Pulmonol. 2007; 42:75–82. © 2006 Wiley‐Liss, Inc.
Functional ability in female leg ulcer patients — a challenge for physiotherapy
Authors: Roaldsen Kirsti Skavberg , Rollman Ola , Torebjörk Erik , Olsson Elisabeth , Stanghelle Johan Kvalvik 
Published: November 2006

AbstractBackground and Purpose. Venous leg ulceration represents a global health problem affecting predominantly elderly women. Traditionally, functional problems in this group of patients have attracted modest attention from wound care providers and physiotherapists. The aim of the present study was to describe and quantify disease consequences in female leg ulcer patients as a background for future physiotherapy interventions, using the nomenclature of the WHO International Classification of Functioning, Disability and Health (ICF). Method. A prospective study was conducted in 34 women aged 60–85 years with current or previous venous leg ulcer as compared to 27 age‐matched non‐ulcer subjects. The outcome variables were pain, ankle range of motion, walking speed, walking endurance, self‐perceived exertion, mobility, activities of daily living (ADL), physical activity, general health, life satisfaction and use of walking aids and community services. Established instruments were utilized and categorized within ICF domains to provide a conceptual framework and basis for physiotherapeutic research. Results. Leg ulcer patients showed significantly reduced values of ankle range of motion, walking speed and endurance, self‐perceived exertion, mobility, ADL and physical activity level as compared to control subjects. Patients suffering from active ulceration were more negatively affected, and more of them had pain than post‐ulcer fellows. By contrast, general health and life satisfaction were similarly rated by the two study groups. Conclusions. Elderly females in our study with chronic leg ulcer of venous aetiology had significant mobility impairments, but the reasons and consequences of these impairments remain to be elucidated. The potential of preventive measures and physical rehabilitation to aid functioning and prospects of leg ulcer repair need to be investigated in future studies. Copyright © 2006 John Wiley & Sons, Ltd.
Solid‐phase synthesis and purification of a set of uniformly 13C, 15N labelled de novo designed membrane fusogenic peptides
Authors: Agrawal Prashant R. , Hofmann Mathias W. , Meeuwenoord Nico J. , Filippov Dmitri V. , Stalz Holger , Hulsbergen Frans , Langosch Dieter , Overkleeft Hermen S. , De Groot Huub 
Published: November 2006

AbstractThe transmembrane segments of soluble N‐ethylmaleimide‐sensitive factor (SNARE) proteins or viral envelope proteins drive membrane fusion, which suggests that simple synthetic biology constructs for fusion exist and can be evaluated. We describe the high‐yield synthesis of a set of de novo designed fusogenic peptides for use in functional investigations, which are highly enriched in 13C and 15N using three equivalents of labelled amino acids and optimized reaction conditions minimizing aggregation. The biomimetic peptides have a high purity >90% and show reproducible and fusogenic activity that correlates well with the intended functional design characteristics, from strongly fusogenic to almost non‐fusogenic. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Limiting racemization and aspartimide formation in microwave‐enhanced Fmoc solid phase peptide synthesis
Authors: Palasek Stacey A. , Cox Zachary J. , Collins Jonathan M. 
Published: November 2006

AbstractMicrowave energy represents an efficient manner to accelerate both the deprotection and coupling reactions in 9‐fluorenylmethyloxycarbonyl (Fmoc) solid phase peptide synthesis (SPPS). Typical SPPS side reactions including racemization and aspartimide formation can occur with microwave energy but can easily be controlled by routine use of optimized methods. Cysteine, histidine, and aspartic acid were susceptible to racemization during microwave SPPS of a model 20mer peptide containing all 20 natural amino acids. Lowering the microwave coupling temperature from 80 °C to 50 °C limited racemization of histidine and cysteine. Additionally, coupling of both histidine and cysteine can be performed conventionally while the rest of the peptide is synthesized using microwave without any deleterious effect, as racemization during the coupling reaction was limited to the activated ester state of the amino acids up to 80 °C. Use of the hindered amine, collidine, in the coupling reaction also minimized formation of D‐cysteine. Aspartimide formation and subsequent racemization of aspartic acid was reduced by the addition of HOBt to the deprotection solution and/or use of piperazine in place of piperidine. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
The way composition affects martensitic transformation temperatures of Ni–Mn–Ga Heusler alloys
Authors: Chen X. Q. , Yang F. J. , Lu X. , Qin Z. X. 
Published: November 2006

AbstractA systematic substitution of Ge, Si, C and Co for Ga in the non‐stoichiometric Ni–Mn–Ga alloys was performed. The relationship between the compositions of different elements including Ni, Mn, Ga, Ge, Si, C, Co, In and martensitic transformation temperature (Ms) was studied in detail for the present alloys together with data collected from a variety of sources. It is found that Ms is a sensitive parameter to the composition. The size factor and electron concentration are usually thought to be the way the composition influences Ms in the Ni–Mn–Ga alloys. Here, analyzing by linear regression, the electron density maybe a most appropriate parameter to describe the way the composition influences Ms when compared with size factor and electron concentration. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of AlN and GaN under pressure: An ab‐initio study
Authors: Laskowski Robert , Christensen Niels Egede 
Published: November 2006

AbstractTheoretically calculated dielectric functions are presented for wurtzite and high pressure rocksalt phases of AlN and GaN. The spectra are calculated in a wide range of photon energies as well as in a a very narrow window near the band gap. The binding energies of excitons have been estimated. For the wurtzite phases they are: 0.105 and 0.033 eV for AlN and GaN, and for the high pressure rocksalt phases they are: 0.11 and 0.061 eV. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrostatic pressure experiments on dilute nitride alloys
Authors: Klar P. J. , Teubert J. , Güngerich M. , Niebling T. , Grüning H. , Heimbrodt W. , Volz K. , Stolz W. , Polimeni A. , Capizzi M. , O'Reilly E. P. , Lindsay A. , Galluppi M. , Geelhaar L. , Riechert H. , Tomić S. 
Published: November 2006

AbstractGaNx As1–x and Ga1–y Iny Nx As1–x are the most prominent members of a novel class of non‐amalgamation type semiconductor alloys where a fraction x of the anions of the host (e.g., GaAs or Ga1–y Iny As) is replaced by N isovalent impurity atoms. The localized N‐states in GaNx As1–x and Ga1–y Iny Nx As1–x form a series of discrete energy levels (e.g., isolated N‐state, N‐pairs and higher order N‐cluster states) resonant with the conduction band of the host. The effect of the alloying with nitrogen on the bandstructure of GaNx As1–x and Ga1–y Iny Nx As1–x can be well parameterized using a band‐anticrossing (BAC) model, namely, assuming a level repulsion between an effective N‐state and the conduction band‐edge state. The dependence of several physical properties on nitrogen incorporation can be predicted qualitatively in the framework of this model, e.g., a tremendous increase of the electron effective mass in GaNx Asx with increasing x, a huge cross section for scattering of electrons by N impurities in electronic transport, etc. Most of these predictions can be tested and verified by performing hydrostatic pressure experiments which, within the picture of the BAC model, allow one to tune continuously the energy difference between the host‐like conduction band edge and the effective N‐level within one and the same specimen. Several examples of this kind will be discussed. Furthermore, we will demonstrate the limitations of the BAC model in the case of GaNx P1–x and also of GaNx As1–x . In particular, we will show several examples where the description by a single effective N‐state fails and that the multiplicity of the N‐states needs to be taken into account. Again hydrostatic pressure experiments prove to be a useful and suitable tool for revealing the effects due to N‐cluster states. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of polarization‐induced electric field screening in InGaN light emitting diodes by means of hydrostatic pressure
Authors: Franssen G. , Suski T. , Perlin P. , Bohdan R. , Trzeciakowski W. , Teisseyre H. , Khachapuridze A. , Targowski G. , Krowicki K. , Czernecki R. , Leszczyński M. , Kurouchi M. , Nanishi Y. , Lu H. , Schaff W. 
Published: November 2006

AbstractWe show that the hydrostatic pressure coefficient dE E/dp of luminescence in Inx Ga1–x N epilayers is in the range 20–38 meV/GPa for the entire alloy (0 ≥ x ≥ 1) and corresponds roughly to the bandgap increase with applied pressure. It is argued that lowering of dE E/dp in quantum structures of InGaN with respect to this range can be attributed to polarization‐induced electric fields (PIEFs). Possible contribution to dE E/dp originating from In‐segregation effects is of secondary importance. This information is used to investigate PIEF screening by free carriers in InGaN‐based light emitting diodes (LEDs). We observe that Si doping at a level of 1019 cm–2 of the barriers in the active region of such LEDs leads to a significant increase of dE E/dp as compared to LEDs with undoped barriers. This is evidence for efficient screening of PIEFs in the Si‐doped devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport measurements under pressure in III–IV layered semiconductors
Authors: Segura A. , Errandonea D. , Martínez‐García D. , Manjón F. J. , Chevy A. , Tobias G. , Ordejón P. , Canadell E. 
Published: November 2006

AbstractThis paper reports on Hall effect, resistivity and thermopower effect measurements under high pressure up to 12 GPa in p‐type γ‐indium selenide (InSe) and ε‐gallium selenide (GaSe). The paper focuses on two applications of transport measurements under pressure: electronic structure and phase transition studies. As concerns the electronic structure, we investigate the origin of the striking differences between the pressure behaviour of transport parameters in both layered compounds. While the hole concentration and mobility increase moderately and monotonously in ε‐GaSe up to 10 GPa, a large increase of the hole concentration at near 0.8 GPa and a large continuous increase of the hole mobility, which doubled its ambient pressure value by 3.2 GPa, is observed in γ‐InSe. Based on electronic structure calculations the difference is found to arise from the pressure evolution of the valence band maximum. While the shape of the valence band maximum is virtually pressure‐insensitive in ε‐GaSe, it changes dramatically in γ‐InSe, with the emergence of a ring‐shaped subsidiary maximum that becomes the absolute valence‐band maximum as pressure increases. Transport measurements as a function of pressure and temperature are also used to investigate the phase diagram of InSe and, in particular, the transition to the rock‐salt polymorph. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dependence of the band‐gap pressure coefficients of self‐assembled InAs/GaAs quantum dots on the quantum dot size
Authors: Kristukat C. , Goñi A. R. , Pötschke K. , Bimberg D. , Thomsen C. 
Published: November 2006

AbstractWe report on low‐temperature photoluminescence experiments on self‐assembled InAs/GaAs quantum dots under high hydrostatic pressure up to 8 GPa using a diamond anvil cell. The sample exhibits a multimodal size distribution of the quantum dots, which gives rise to a characteristic emission profile displaying up to nine clearly separable peaks attributed to the ground‐state recombination from each quantum dot subensemble with different size. Structural analysis revealed that their size differs in entire monolayer steps. The measured pressure coefficients for each subensemble show a linear dependence on their zero‐pressure emission energy ranging from 65 meV/GPa for the largest dots to 112 meV/GPa for the smallest ones. Pressure dependent strain simulations based on an atomistic valence‐force field yield that the pressure coefficient of the InAs band‐gap is strongly reduced when InAs is embedded in a GaAs matrix. Taking into account confinement effects within the envelope function approximation, the calculated pressure coefficients are in good agreement with the experimental findings. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of pressure on the Raman scattering of wurtzite AlN
Authors: Manjón F. J. , Errandonea D. , Garro N. , Romero A. H. , Serrano J. , Kuball M. 
Published: November 2006

AbstractHigh‐pressure Raman spectra of wurtzite aluminum nitride were measured up to 25 GPa. The Raman‐active modes in wurtzite‐AlN were obtained up to the wurtzite‐to‐rocksalt transition at 20 GPa and their pressure coefficients compared with those obtained from ab initio lattice dynamics calculations. A slight decrease of the LO–TO splitting under pressure has been measured. We also report Raman scattering of the rocksalt phase of AlN during downstroke. The comparison of previously reported Raman scattering in rocksalt‐GaN and ab initio calculations suggests that the Raman scattering we have measured in rocksalt‐AlN likely corresponds to the one‐phonon density of states of the rocksalt phase. A partial return to the wurtzite phase is found at ambient pressure after fully releasing pressure. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)