bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation, antimicrobial activity, and toxicity of 2‐amino‐4‐arylthiazole derivatives
Authors: Morales‐Bonilla Pedro , Pérez‐Cardeña Andrea , Quintero‐Mármol Esther , Arias‐Téllez José Luis , Mena‐Rejón Gonzalo J.
Published: May 2006

Seven 2‐amino‐4‐aryl‐1,3‐thiazoles (1a–g) and their corresponding 2‐aminoacetyl (2a–g) and 2‐aminoacetyl‐5‐bromo (3a–g) derivatives were synthesized and tested in vitro against 11 reference strains, three Gram‐positive and four Gram‐negative bacteria, two yeasts, and two moulds. Toxicity of the compounds was also evaluated using the brine shrimp test. Compounds1a, 1b, 1e–g, and3bshowed moderate antimicrobial activity at different concentrations. The results indicated that acetylation of the amino group and bromination at position 5 of the thiazole moiety cause lost of activity. Compounds1a, 1e, and1fshowed toxicity to brine shrimp nauplii below 10 ppm. Most other compounds showed moderate toxicity, LD50above 100 ppm. Structures of all compounds were confirmed by NMR and MS data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:254–260, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20182
Stereoselective synthesis and conformational analysis of aromatic C‐thionucleosides
Authors: Juárez Ernesto , García Adriana , Hommer Herbert , Salas Magali , Gordillo Barbara
Published: May 2006

Tetrahydrothiophene derivatives 2a–2d, which are useful intermediates in the synthesis of C‐thionucleosides, were obtained by a tandem strategy that involves the base‐catalyzed conjugate addition of ethyl 2‐mercaptoacetate to trans‐cinnamaldehyde followed by cyclization. The solvent and the nature of the amine used as Lewis base influence the stereo‐ selectivity of the reaction. The reduction of each isolated derivative 2a–2d was performed with LiAlH4 to afford C‐thionucleosides 3a–3d. The configuration and conformation of each diastereomer 2a–2d and 3a–3d was assigned by means of the analysis of vicinal proton–proton coupling constants. The X‐ray structure of 2d, 3a, and 3b confirmed the configuration assigned to each isomeric tetrahydrothiophenes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:289–298, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20205
New approaches to the synthesis of diphosphine dioxides and hypophosphoric acid esters
Authors: Nycz Jacek E. , Musiol Robert
Published: May 2006

An anion >P–O− has been applied as an efficient synthetic precursor of four coordination compounds of the R2P(O)–(O)PR2 type, namely diphosphine dioxides (R = alkyl, aryl) as well as hypophosphoric acid esters (R = alkoxy, aryloxy), in a one‐pot reaction. Furthermore, there were elaborated some mechanistic aspects of the origin of the >P(O)–O–(O)P< anhydride, as a side‐product of the reaction between the anion >P–O− and >P(O)X (X = Cl, Br) electrophiles. Attention is focused on the synthesis of the >P(O)–(O)P< compounds. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:310–316, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20208
Regioselective N‐alkylation for the synthesis of novel aminotriazolophanes
Authors: Chande M. S. , Uchil Meera H. , Barve P. A.
Published: May 2006

Regioselective synthesis of macrocycles, incorporating 3‐oxo‐4‐amino‐1,2,4‐triazole derivatives, has been achieved by reactions involving N‐alkylation, utilizing appropriate 1, ω ‐dihaloalkanes in the presence of metal hydroxide. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:329–336, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20211
A generalized CAD model for the full‐wave modelling of microstrip line and its regular and irregular discontinuities
Authors: Mayouf A. , Mayouf F. , Djahli F.
Published: May 2006

In this paper we present a new theoretical model for the modelling of the microstrip line as well as two types of discontinuities: regular (open end, step, bend and T‐ and cross‐junctions) and irregular (stub and bent‐stub). The two‐dimensional exact dyadic Green function of a grounded dielectric slab has been used with the Galerkin's technique. The subdivision of the discontinuity in a network of juxtaposed unit cells, characterized by their own longitudinal and transversal current distributions, allowed the treatment of a large class of irregular discontinuities in addition to the regular discontinuities. The obtained results have been commented and compared with those of different approaches and with experimental results where a good concordance has been observed. Copyright © 2006 John Wiley & Sons, Ltd.
Biodegradable Heparin‐Loaded Microspheres: Carrier Molecular Composition and Microsphere Structure
Authors: Luo Xianglin , Qiu Di , He Bin , Wang Lijian , Luo Juan
Published: May 2006

Summary: Microspheres of amphiphilic triblock polymers PLLA‐PEG‐PLLA were investigated as carriers for heparin delivery. Two series of PLLA‐PEG‐PLLA triblock were synthesized and prepared into microspheres with heparin loaded. The microspheres were hollow and the surface morphology varied from smooth to porous. The pore size increased with increasing PEG content. The microsphere size distribution showed that higher PEG content increased the average microsphere size. The release rate of heparin was closely related to the surface morphology of the microspheres. DSC spectra showed that both cold crystalline temperature (Tc) and crystalline melting temperature (Tm) of heparin‐loaded microspheres were related to the copolymer composition and the Tc was lower than those of corresponding pure microspheres.

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The wet corrosion of molybdenum thin film – Part III: The effect of Ti and Nb
Authors: Tomachuk C. R. , Mitton D. B. , Springer J. , Monetta T. , Bellucci F.
Published: May 2006

Magnetron sputtering has become the process of choice for the deposition of a wide range of industrially important coatings. Over the last decade, interest in molybdenum thin films prepared by magnetron sputtering has been increasing; however, little research has been done on molybdenum‐titanium and molybdenum‐niobium alloy thin films. During the current study, electrochemical impedance spectroscopy (EIS) was employed to investigate the effect on the corrosion resistance in basic chloride environments of adding titanium and niobium species to molybdenum thin films deposited by physical vapor deposition. The results indicate that the MoTi alloy thin films exhibit better protective properties than either the molybdenum‐niobium alloy or unalloyed molybdenum thin films.
Acetic acid – direct corrosive mediator in SCC of titanium/ethanol system
Authors: Jiang Y. , Wu Y. , Wang K.
Published: May 2006

Although so many researchers paid attention on stress corrosion mechanism of titanium/ethanol system, few papers explained why ethanol, a very weak corrosive mediator, caused severe anodic solution. We found that the anodic polarization process of the titanium/ethanol system produced lots of acetic acid, which caused the pH value decreased rapidly. Maybe the acetic acid was the direct reason of stress corrosion susceptibility of titanium alloy in ethanol. And SSR tests proved that acetic acid could accelerate SCC of this system seriously. Also we found that in this system when the specimen was in the yield region, its corrosion potential fluctuated and PDS analysis showed this fluctuation was not a pure random process but a random fluctuation superposed with a definitive quasi‐sine wave. We thought that it was acetic acid made the passive film unstable and this unstable state was the main reason caused SCC in this system.
Neurotization with the brachialis muscle motor nerve
Authors: Palazzi Santos , Palazzi José‐Luis , Caceres Juan‐Pablo
Published: May 2006

Function of the wrist and hand in lower root avulsions is severely impaired. Based on anatomic and experimental studies which suggest that the motor nerve of the brachialis muscle could be used as a selective neurotizator in lower root avulsions with intact C5–C6 ± C7 roots (Klumpke paralysis), we considered its use depending on the target. We describe two techniques for the median nerve (in C8–T1 avulsions) and one for the radial nerve (in C7–C8–T1 avulsions). In all cases, we added the lateral cutaneous nerve of the forearm in the neurotization to improve sensibility in the hand. The present report presents the results of its use in our first five patients. © 2006 Wiley‐Liss, Inc. Microsurgery, 2006.
Saturated double‐angle method for rapid B1+ mapping
Authors: Cunningham Charles H. , Pauly John M. , Nayak Krishna S.
Published: May 2006

For in vivo magnetic resonance imaging at high field (≥3 T) it is essential to consider the homogeneity of the active B1 field (B1+), particularly if surface coils are used for RF transmission. A new method is presented for highly rapid B1+ magnitude mapping. It combines the double angle method with a B1‐insensitive magnetization‐reset sequence such that the choice of repetition time (TR) is independent of T1 and with a multislice segmented (spiral) acquisition to achieve volumetric coverage with adequate spatial resolution in a few seconds. Phantom experiments confirmed the accuracy of this technique even when TR ≪ T1, with the side effect being lowered SNR. The speed of this method enabled B1+ mapping in the chest and abdomen within a single breath‐hold. In human cardiac imaging, the method enabled whole‐heart coverage within a single 16‐s breath‐hold. Results from phantoms and healthy volunteers at 1.5 T and 3 T are presented. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Structural arrangement of crystalline/amorphous phases of polyethylene‐block‐polystyrene copolymer as induced by orientation techniques
Authors: Uehara Hiroki , Yoshida Tomoyuki , Kakiage Masaki , Yamanobe Takeshi , Komoto Tadashi
Published: May 2006

A polyethylene‐block‐polystyrene copolymer film having a bicontinuous crystalline/amorphous phases was tensile‐drawn under various conditions for the structural arrangement of these phases. The prepared film could be drawn below the melting temperature of the polyethylene component, with the highest drawability obtained at 60°C. However, the initial bicontinuous structure was gradually destroyed with increasing strain because the drawing temperature was lower than the glass‐transition temperature of the polystyrene component. Correspondingly, a necking phenomenon was clearly recognizable when samples were drawn. In contrast, drawing near the melting temperature of the polyethylene component produced less orientation of both the crystalline and amorphous phases, resulting in homogeneous deformation with lower drawing stress. These results indicated that the modification of the lower ductility of the polystyrene component was key to the effective structural arrangement of both phases by tensile drawing. Here, a solvent‐swelling technique was applied to improve polystyrene deformability even below its glass‐transition temperature. Tensile drawing after such a treatment successfully induced the orientation of both the crystalline and amorphous phases while retaining their initial continuities. A change in the deformation type from necking to homogeneous deformation was also confirmed for the stress–strain behavior. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1731–1737, 2006
Specific heat calculations of III‐N bulk materials
Authors: AlShaikhi A. , Srivastava G. P.
Published: May 2006

We have carried out calculations of the specific heat of the cubic and hexagonal phases of BN, AlN, GaN and InN by employing lattice dynamical results from an adiabatic bond charge model. While each phonon polarization branch contributes equally at high temperatures, it is found that the transverse acoustic branches contribute more at low temperatures. These results, which compare well with available experimental measurements, are used to test the applicability of the routinely employed Debye model based on an isotropic continuum dispersion scheme. The specific heat of the hexagonal phase is predicted to be higher than of the cubic phase at quite low temperatures. A trend in the variation of the specific heat across the sequence BN ‐ AlN ‐ GaN ‐ InN has been established in terms of their molar masses. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of carrier gas on GaN epilayer characteristics
Authors: Cho Y. S. , Hardtdegen H. , Kaluza N. , Thillosen N. , Steins R. , Sofer Z. , Lüth H.
Published: May 2006

Metalorganic vapor phase epitaxy (MOVPE) of GaN was performed using hydrogen (H2), nitrogen (N2) and H2/N2mixtures thereof as the carrier gas in the high temperature buffer growth range. The effect of carrier gas on the structural and morphological characteristics of the epilayers was systematically studied using interference and atomic force microscopy (AFM), photoluminescence (PL) measurements at 2 K, Raman spectroscopy and X‐ray diffraction (XRD). The higher the N2 content in the carrier gas, the more pinholes are observed, the lower compressive strain and the higher dislocation density in the layers. A carrier gas composition range was defined at which GaN layers with acceptable structural and morphological characteristics are achieved. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Piezoelectric properties of thin AlN layers for MEMS application determined by piezoresponse force microscopy
Authors: Tonisch K. , Cimalla V. , Foerster Ch. , Dontsov D. , Ambacher O.
Published: May 2006

Piezoelectric properties of aluminium nitride thin films were measured using both, the piezoresponse force microscopy and an interferometric technique. Wurtzite AlN thin films were prepared on Si (111) substrates by reactive DC‐sputtering and by metalorganic chemical vapor deposition. Direct measurements of the inverse piezoelectric effect in the picometer range showed that the acceptable tolerance in the crystal orientation is much larger for MEMS applications than expected previously. The value of the piezoelectric coefficient d33for the prepared AlN thin films was determined to be 5.36 ± 0.25 pm/V for highly textured as well as for polycrystalline thin films with a (002) preferential orientation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallization of free standing bulk GaN by HVPE
Authors: Łucznik B. , Pastuszka B. , Grzegory I. , Boćkowski M. , Kamler G. , Domagała J. , Nowak G. , Prystawko P. , Krukowski S. , Porowski S.
Published: May 2006

Gallium nitride was crystallized on 2 inch MOVPE GaN/sapphire substrates by Hydride Vapor Phase Epitaxy. A stable growth has been achieved in long duration (>10 h) processes at growth rates bigger than 100 μm/h. As a result, entirely transparent and colorless bulk crystals with thickness exceeding 2 mm were obtained. The cracks in the thick HVPE GaN layers deposited on the MOVPE GaN/sapphire substrates can appear especially during cooling of the system after crystallization. It is shown that the formation of cracks at cooling is dependent on the gradients in the layer thickness The relaxation of strains in the resulting crystal coupled to the substrate leads to the self separation of GaN from sapphire. (At present 30 x 30 x 2 mm free standing bulk GaN crystals are obtained). The GaN crystals are characterized by defect selective etching (DSE) and X‐ray diffraction. The density of threading dislocations (measured by DSE of (0001) surface) decreases with the thickness of the HVPE layer and becomes lower than 107 cm–2 in the layers thicker than app. 1 mm. The X‐ray rocking curves for (0002) reflection (slit 0.5 x 0.1 mm) are in the range of 80–95 arcsec. However, larger scans reveal bending of crystallographic {0001} planes. The behavior of these “deformed” free standing crystals used as substrates for HVPE re‐growth is also analyzed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polishing and characterization of thick AlN layers grown on SiC substrates by stress control hydride vapor phase epitaxy
Authors: Mank H. , Amstatt B. , Turover D. , Bellet‐Amalric E. , Daudin B. , Ivantsov V. , Dmitriev V. , Maslennikov V.
Published: May 2006

In this paper, we report new results on polishing and characterization of thick aluminium nitride (AlN) layers grown on 2‐ and 3‐inch electrically conducting 4H‐SiC on‐axis substrate. As thick as 10‐22 µm AlN layers were deposited on Si‐face by stress control hydride vapor phase epitaxy. Rough as‐grown layers were polished to provide epi‐ready surface for device epitaxy. Surface morphology and surface defects of AlN were studied by atomic force microscopy, optical microscopy and scanning electron microscopy. The root mean square surface roughness was drastically decreased from 470 Å for as‐grown surface to less than 3 Å and the peak to valley value was decreased from 345 nm to less than 3 nm. As‐grown and polished epilayer thickness homogeneity, verified by Fourier transform infrared (FTIR) reflectivity, is better than 5%. Structural properties were investigated by X‐ray diffraction (XRD). XRD rocking curves were measured in ω‐scanning mode for the (00.2) and (10.2) reflections. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust Regression using Probability Plots for Estimating the Weibull Shape Parameter
Authors: Zhang L.‐F. , Xie M. , Tang L.‐C.
Published: May 2006

The Weibull shape parameter is important in reliability estimation as it characterizes the ageing property of the system. Hence, this parameter has to be estimated accurately. This paper presents a study of the efficiency of using robust regression methods over the ordinary least‐squares regression method based on a Weibull probability plot. The emphasis is on the estimation of the shape parameter of the two‐parameter Weibull distribution. Both the case of small data sets with outliers and the case of data sets with multiple‐censoring are considered. Maximum‐likelihood estimation is also compared with linear regression methods. Simulation results show that robust regression is an effective method in reducing bias and it performs well in most cases. Copyright © 2006 John Wiley & Sons, Ltd.
Development of a Rapid Prototyping System using Response Surface Methodology
Authors: Palmer Kurt , Asiabanpour Bahram , Khoshnevis Behrokh
Published: May 2006

This case study presents an investigation of the relationships between eight process operating variables (factors) and five part performance measures (responses) in a rapid prototyping system. The use of fractional factorial, single‐factor foldover, and central composite designs is demonstrated. Polynomial regression models are constructed for each response, followed by a desirability function model. Canonical and ridge analyses are used to identify a group of factor settings that simultaneously produce improved performance for all responses. Copyright © 2006 John Wiley & Sons, Ltd.
A Comparative Study of Joint Monitoring Schemes for APC Processes
Authors: Jiang Wei , Shu Lianjie , Tsung Fugee
Published: May 2006

To monitor processes under automatic process control (APC), several joint monitoring schemes have recently been proposed, such as the U statistics, $U_{0}$ and $U_{\infty}$, that originate from the uniformly most powerful test. It is known that the $U_{0}$ chart is sensitive to large shift detection whereas the $U_{\infty}$ chart is sensitive to small shift detection. To take advantage of both charts, this paper examines a combined use of the two U charts. A comparative study indicates that the combined procedure improves over a single U chart and performs better than other joint monitoring schemes, including Hotelling's $T^2$ chart for APC processes. Copyright © 2006 John Wiley & Sons, Ltd.
Set theoretic formulation of performance reliability of multiple response time‐variant systems due to degradations in system components
Authors: Son Young Kap , Savage Gordon J.
Published: May 2006

This paper presents a design stage method for assessing performance reliability of systems with multiple time‐variant responses due to component degradation. Herein the system component degradation profiles over time are assumed to be known and the degradation of the system is related to component degradation using mechanistic models. Selected performance measures (e.g. responses) are related to their critical levels by time‐dependent limit‐state functions. System failure is defined as the non‐conformance of any response and unions of the multiple failure regions are required. For discrete time, set theory establishes the minimum union size needed to identify a true incremental failure region. A cumulative failure distribution function is built by summing incremental failure probabilities. A practical implementation of the theory can be manifest by approximating the probability of the unions by second‐order bounds. Further, for numerical efficiency probabilities are evaluated by first‐order reliability methods (FORM). The presented method is quite different from Monte Carlo sampling methods. The proposed method can be used to assess mean and tolerance design through simultaneous evaluation of quality and performance reliability. The work herein sets the foundation for an optimization method to control both quality and performance reliability and thus, for example, estimate warranty costs and product recall. An example from power engineering shows the details of the proposed method and the potential of the approach. Copyright © 2006 John Wiley & Sons, Ltd.
Regular subgraphs of random graphs
Authors: Bollobás Béla , Kim Jeong Han , Verstraëte Jacques
Published: May 2006

In this paper, we prove that there exists a function ρk = (4 + o(1))k such that G(n,ρ/n) contains a k−regular graph with high probability whenever ρ > ρk. In the case of k = 3, it is also shown that G(n,ρ/n) contains a 3−regular graph with high probability whenever ρ > λ ≈︁ 5.1494. These are the first constant bounds on the average degree in G(n,p) for the existence of a k−regular subgraph. We also discuss the appearance of 3−regular subgraphs in cores of random graphs. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Non‐parametric estimation for baseline hazards function and covariate effects with time‐dependent covariates
Authors: Gao Feng , Manatunga Amita K. , Chen Shande
Published: May 2006

Often in many biomedical and epidemiologic studies, estimating hazards function is of interest. The Breslow's estimator is commonly used for estimating the integrated baseline hazard, but this estimator requires the functional form of covariate effects to be correctly specified. It is generally difficult to identify the true functional form of covariate effects in the presence of time‐dependent covariates. To provide a complementary method to the traditional proportional hazard model, we propose a tree‐type method which enables simultaneously estimating both baseline hazards function and the effects of time‐dependent covariates. Our interest will be focused on exploring the potential data structures rather than formal hypothesis testing. The proposed method approximates the baseline hazards and covariate effects with step‐functions. The jump points in time and in covariate space are searched via an algorithm based on the improvement of the full log‐likelihood function. In contrast to most other estimating methods, the proposed method estimates the hazards function rather than integrated hazards. The method is applied to model the risk of withdrawal in a clinical trial that evaluates the anti‐depression treatment in preventing the development of clinical depression. Finally, the performance of the method is evaluated by several simulation studies. Copyright © 2006 John Wiley & Sons, Ltd.
Platelet‐activating factor‐induced NF‐κB activation enhances VEGF expression through a decrease in p53 activity
Authors: Ko Hyun-Mi , Jung Hae Hyun , Seo Kook Heon , Kang Yeong-Rim , Kim Han-A , Park Sung Jun , Lee Hern-Ku , Im Suhn-Young
Published: May 2006

We investigated the role of p53 in nuclear factor (NF)‐κB dependent, platelet‐activating factor (PAF)‐induced vascular endothelial growth factor (VEGF) expression. Transfected NF‐κB subunits in ECV304 cells increased the tumor necrosis factor‐α promoter activity, which was completely inhibited by p53. Transfected p53 increased p53RE promoter activity, which was completely inhibited by NF‐κB subunits, indicating that cross‐regulation occurs between NF‐κB and p53. PAF‐induced increase in VEGF expression was correlated with decreased p53 activity. These data suggest that NF‐κB‐dependency of the PAF‐induced increase in VEGF expression is due to decreased p53 activity, which is reciprocally regulated by increased NF‐κB activity.
PFKFB3 gene silencing decreases glycolysis, induces cell‐cycle delay and inhibits anchorage‐independent growth in HeLa cells
Authors: Calvo M.N. , Bartrons R. , Castaño E. , Perales J.C. , Navarro-Sabaté A. , Manzano A.
Published: May 2006

The high rate of glycolysis despite the presence of oxygen in tumor cells (Warburg effect) suggests an important role for this process in cell division. The glycolytic rate is dependent on the cellular concentration of fructose 2,6‐bisphosphate (Fru‐2,6‐P2), which, in turn, is controlled by the bifunctional enzyme 6‐phosphofructo‐2‐kinase/fructose‐2,6‐bisphosphatase (PFK‐2). The ubiquitous PFK‐2 isoenzyme (uPFK‐2, alternatively named UBI2K5 or ACG) coded by the pfkfb3 gene is induced by different stimuli (serum, progesterone, insulin, hypoxia, etc.) and has the highest kinase/phosphatase activity ratio amongst all PFK‐2 isoenzymes discovered to date, which is consistent with its role as a powerful activator of glycolysis. uPFK‐2 is expressed in brain, placenta, transformed cells and proliferating cells. In the present work, we analyze the impact of small interfering RNA (siRNA)‐induced silencing of uPFK‐2 on the inhibition of cell proliferation. HeLa cells treated with uPFK‐2 siRNA showed a decrease in uPFK‐2 RNA levels measured at 24 h. uPFK‐2 protein levels were severely depleted at 48–72 h when compared with cells treated with an unrelated siRNA, correlating with decreased glycolytic activity, Fru‐2,6‐P2, lactate and ATP concentrations. These metabolic changes led to reduced viability, cell‐cycle delay and an increase in the population of apoptotic cells. Moreover, uPFK‐2 suppression inhibited anchorage‐independent growth. The results obtained highlight the importance of uPFK‐2 on the regulation of glycolysis, on cell viability and proliferation and also on anchorage‐independent growth. These data underscore the potential for uPFK‐2 as an effective tumor therapeutic target.
POSH, a scaffold protein for JNK signaling, binds to ALG‐2 and ALIX in Drosophila
Authors: Tsuda Manabu , Seong Ki-Hyeon , Aigaki Toshiro
Published: May 2006

Plenty of SH3s (POSH) functions as a scaffold protein for the Jun N‐terminal kinase (JNK) signal transduction pathway, which leads to cell death in mammalian cultured cells and Drosophila. Here, we show that POSH forms a complex with Apoptosis‐linked gene‐2 (ALG‐2) and ALG‐2‐interacting protein (ALIX/AIP1) in a calcium‐dependent manner. Overexpression of ALG‐2 or ALIX in developing imaginal eye discs resulted in roughened or melanized eyes, respectively. These phenotypes were enhanced by co‐overexpression of POSH. We found that overexpression of either gene could induce ectopic JNK activation, suggesting that POSH/ALG‐2/ALIX may function together in the regulation of the JNK pathway.
Relationship between middle stratiform clouds and large scale circulation over eastern China
Authors: Li Yunying , Gu Hong
Published: May 2006

Eastern China is the globally unique land region with lots of middle stratiform clouds in cold seasons. The distribution of this specific stratiform cloud is determined by three main factors, viz, relative humidity, stable stratification, and ascending motions. The large relative humidity in cold seasons provides a basic moisture condition for clouds, the ascending motions generated by the convergence in the low atmosphere and divergence in the middle troposphere provide a favorable dynamical condition for middle clouds, and the midlatitude temperature inversion provides a favorable stable stratification for the stratiform clouds. In addition, the co‐effects of the divergence in the low and middle atmosphere dominate the middle stratiform cloud amount over eastern China.
Effect of ocean mesoscale variability on the mean state of tropical Atlantic climate
Authors: Seo Hyodae , Jochum Markus , Murtugudde Raghu , Miller Arthur J.
Published: May 2006

A regional coupled ocean‐atmospheric model is used to investigate the effect of oceanic mesoscale features on the mean climate of the tropical Atlantic. It is shown that, compared to a non‐eddy resolving ocean model, resolving oceanic mesoscale variability leads to a cooler mean equatorial cold tongue and a cooler coastal upwelling zone. This changes the meridional SST gradient, and the resulting weaker low‐level convergence reduces the mean of rainfall in the marine Inter‐Tropical Convergence Zone (ITCZ). The reduced rainfall and the cooler coastal upwelling regions represent a clear improvement of the model solution.
Precipitation mechanisms in east Asian monsoon: Videosonde study
Authors: Takahashi Tsutomu
Published: May 2006

During the past 12 years, more than 200 videosondes have been launched into monsoon clouds from 13 different locations in east Asia. Storm precipitation mechanisms have been investigated using videosonde data giving hydrometeor type in clouds monitored by radar. At each location, different monsoon cloud systems develop in unique synoptic disturbances. In the east Asian monsoon area, rain is divided into three different regimes with respect to the precipitation mechanism occurring in each. The frozen drop process (frozen) occurs over the open ocean, and the ice process (cool) occurs over the inland desert. Over a maritime continent, both frozen and ice processes (mixed) are held. Heavy rain is produced by extensive growth of graupel and frozen drops in the convective center near the melting level. Further raindrop growth at the lower levels leads to very high rainwater content in the “mixed” region. Number concentrations of ice crystals and graupel (frozen drops) were very low over the open ocean where lightning frequency is also low. In east Asia, ice crystal and graupel (frozen drops) concentrations are closely related to lightning activity.
Combining size distribution and chemical species measurements into a multivariate receptor model of PM2.5
Authors: Larson Timothy V. , Covert David S. , Kim Eugene , Elleman Robert , Schreuder Astrid B. , Lumley Thomas
Published: May 2006

We introduce an extended receptor model, implemented with the multilinear engine ME2, which combines simultaneous but separate filter‐based species information with size‐resolved particle volume information. Our chemical data set consisted of 24‐hour filter measurements reported by the EPA Speciation Trends Network at Beacon Hill in Seattle, Washington, from February 2000 to June 2003. We measured the particle size distribution at this site from December 2000 to April 2002 using a differential mobility particle sizer (DMPS) and an aerodynamic particle sizer (APS). The combined model extends the traditional chemical mass balance approach by including a simultaneous set of conservation equations for both particle mass and volume, linked by a unique value of apparent particle density for each source. The model distinguished three mobile source features, two consistent with previous identifications of “gasoline” and “diesel” sources, and an additional minor feature enriched in EC, Fe and Mn and ultrafine particle mass that would have been difficult to interpret in the absence of particle size information. This study has also demonstrated the feasibility of defining missing mass as an additional variable, and thereby providing additional useful model constraints and eliminating the posthoc regression step that is traditionally used to rescale the results.
Hydropedology: Synergistic integration of pedology and hydrology
Authors: Lin Henry , Bouma Johan , Pachepsky Yakov , Western Andrew , Thompson James , van Genuchten Rien , Vogel Hans‐Jörg , Lilly Allan
Published: May 2006

This paper presents a vision that advocates hydropedology as an advantageous integration of pedology and hydrology for studying the intimate relationships between soil, landscape, and hydrology. Landscape water flux is suggested as a unifying precept for hydropedology, through which pedologic and hydrologic expertise can be better integrated. Landscape water flux here encompasses the source, storage, flux, pathway, residence time, availability, and spatiotemporal distribution of water in the root and deep vadose zones within the landscape. After illustrating multiple knowledge gaps that can be addressed by the synergistic integration of pedology and hydrology, we suggest five scientific hypotheses that are critical to advancing hydropedology and enhancing the prediction of landscape water flux. We then present interlinked strategies for achieving the stated vision. It is our hope that by working together, hydrologists and pedologists, along with scientists in related disciplines, can better guide data acquisition, knowledge integration, and model‐based prediction so as to advance the hydrologic sciences in the next decade and beyond.
Complementary relationship between daily evaporation in the environment and pan evaporation
Authors: Kahler David M. , Brutsaert Wilfried
Published: May 2006

Daily actual evaporation observed locally is compared to daily pan evaporation to clarify and test the validity of the complementary relationship at this timescale. For this purpose, use was made of actual evaporation measurements at two sites, namely, in the Konza Prairie, Kansas, during the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment, and in the Little Washita River Basin, Oklahoma, as part of the Atmospheric Radiation Measurement Program. The corresponding pan evaporation data were obtained from nearby class A pan stations. The results of the analyses confirm the complementary relationship at this shorter timescale and lead to a procedure to estimate actual landscape evaporation by means of net radiation and pan evaporation data; they also provide support for the notion that even under conditions of decreasing incoming radiation, a negative trend in pan evaporation may still indicate a positive trend in landscape evapotranspiration.
Sea‐surface temperatures and tropical cyclones in the Atlantic basin
Authors: Michaels Patrick J. , Knappenberger Paul C. , Davis Robert E.
Published: May 2006

Whereas there is a significant relationship between overall sea‐surface temperature (SST) and tropical cyclone intensity, the relationship is much less clear in the upper range of SST normally associated with these storms. There, we find a step‐like, rather than a continuous, influence of SST on cyclone strength, suggesting that there exists a SST threshold that must be exceeded before tropical cyclones develop into major hurricanes. Further, we show that the SST influence varies markedly over time, thereby indicating that other aspects of the tropical environment are also critically important for tropical cyclone intensification. These findings highlight the complex nature of hurricane development and weaken the notion of a simple cause‐and‐effect relationship between rising SST and stronger Atlantic hurricanes.
Density functional theory study of water dissociation in a double water bilayer with or without coadsorption of CO on Pt(111)
Authors: Wang J. G. , Hammer B.
Published: May 2006

Using density functional theory, we investigate the structure of the double water bilayer with or without coadsorption of CO on Pt(111). The double water bilayer consists of two bilayers. Each bilayer is buckled with every second water molecule being closer to the surface than every other water molecule. CO is found to adsorb most strongly when substituting in the first bilayer, the water molecule closest to the surface. Dissociation of H2O in the water bilayer (with or without CO) is further considered. A great number of pathways for the dissociation are studied. These include homolytic pathways where both dissociation products end up adsorbed on the Pt surface and heterolytic pathways where only the OH is adsorbed, while a proton is transferred to the water adlayers. We find that the heterolytic dissociation pathways are energetically more favorable than the homolytic ones, yet they are all rather endothermic. The most favorable pathways found have reaction energies of 0.60 and 0.52eV without and with CO present. The corresponding activation energies are 0.99 and 0.53eV, respectively.
Simulated annealing study of asymmetric diblock copolymer thin films
Authors: Yin Yuhua , Sun Pingchuan , Jiang Run , Li Baohui , Chen Tiehong , Jin Qinghua , Ding Datong , Shi An-Chang
Published: May 2006

We report a simulated annealing study of the morphology of asymmetric diblock copolymer thin films confined between two homogeneous and identical surfaces. We have focused on copolymers that form a gyroidal morphology in the bulk. The morphological dependence of the confined films on the film thickness and the surface-polymer interaction has been systematically investigated. From the simulations it is found that much richer morphologies can form for the gyroid-forming asymmetric diblock copolymer thin films, in contrast to the lamella-forming symmetric and cylinder-forming asymmetric diblock copolymer films. Multiple morphological transitions induced by changing the film thickness and polymer-surface interactions are observed.
Excitation wavelength dependence of the Raman-Stokes shift of N,N-dimethyl-p-nitroaniline
Authors: Fujisawa T. , Terazima M. , Kimura Y.
Published: May 2006

Raman spectra of N,N-dimethly-p-nitroaniline have been measured in various solvents. The Raman-Stokes shift of the band assigned to the NO2 stretching mode excited at 488nm was found to be linearly dependent on the π-π* absorption band center. Furthermore, it is found that the Raman-Stokes shift of the NO2 stretching mode is dependent upon the excitation wavelength. The extent of the shift when excited at 355 versus 488nm is almost linearly dependent on the vibrational bandwidth of the NO2 mode. The phenomenon is interpreted as the result of the solvation state selective excitation of the vibrational mode as in the case of phenol blue [Yamaguchi et al., J. Chem. Phys. 109, 9075 (1998); 109, 9084 (1998)].
Equilibrium conformational dynamics of a polymer in a solvent
Authors: Polson James M. , Gallant John P.
Published: May 2006

Molecular dynamics simulations were used to study the conformational dynamics of a bead-spring model polymer in an explicit solvent under good solvent conditions. The dynamics of the polymer chain were investigated using an analysis of the time autocorrelation functions of the Rouse coordinates of the polymer chain. We have investigated the variation of the correlation functions with polymer chain length N, solvent density ρ, and system size. The measured initial decay rates Γp of the correlation functions were compared with the predictions from a theory of polymer dynamics which uses the Oseen tensor to describe hydrodynamic interactions between monomers. Over the range of chain lengths considered (N=30–60 monomers), the predicted scaling of Γp∝N−3ν was observed at high ρ, where ν is the polymer scaling exponent. The predicted Γp are generally higher than the measured values. This discrepancy increases with decreasing ρ, as a result in the breakdown in the conditions required for the Oseen approximation. The agreement between theory and simulation at high ρ improves considerably if the theoretical expression for Γp is modified to avoid sum-to-integral approximations, and if the values of ⟨Rp2⟩, which are used in the theory, are taken directly from the simulation rather than being calculated using approximate scaling relations. The observed finite-size scaling of Γp is not quantitatively consistent with the theoretical predictions.
Dependence of image distortion in a liquid-cell atomic force microscope on fluidic properties
Authors: Kim Younghun , Kang Sung Koo , Choi Inhee , Lee Jeongjin , Yi Jongheop
Published: May 2006

When the standard grating sample was tested in seven different fluids using a liquid atomic force microscope, it was observed that the images were significantly distorted. It was proposed as a modified squeeze-drag superposition model for the elucidation of image distortion. This model considers the net force between the cantilever and the sample for scanning with the y direction. It was found that the net force between the cantilever and the sample was strongly dependent on the kinematic viscosity of fluids. These image distortion phenomena were proven by the proposed model with the experiments.
Efficient, color-stable fluorescent white organic light-emitting diodes with single emission layer by vapor deposition from solvent premixed deposition source
Authors: Jou Jwo-Huei , Chiu Yung-Sheng , Wang Chung-Pei , Wang Ren-Yang , Hu Huei-Ching
Published: May 2006

Efficient, color-stable fluorescent white organic light-emitting diodes (OLEDs) with single emission layer were fabricated by vapor deposition from solvent premixed mixtures of 1,4-bis(2,2-diphenylvinyl)biphenyl doped with 4-(dicyanomethylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran and/or 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-(1)benzopy-rano(6,7,8-l, j)quinolizine-11-one. The power efficiencies at 100 cd/m2 were 4.6 lm/W for the two-spectrum pure white OLEDs and 7.2 lm/W m2 for the three-spectrum ones with white emission. By using a different host of 10,10′-bis(biphenyl-4-yl)-9,9′-bianthryl and a greenish-blue dye of di(triphenylamine)-1,4-divinylnaphthalene, the three-spectrum OLEDs with a power efficiency of 6.8 lm/W at 100 cd/m2 were obtained.
Heterodyne speckle velocimetry
Authors: Alaimo M. D. , Magatti D. , Ferri F. , Potenza M. A. C.
Published: May 2006

We present a simple method for fluid velocimetry based on the velocity of the heterodyne speckles generated by tracking particles illuminated with coherent light. It works in real time and provides instantaneous two-dimensional velocity mappings in the direction orthogonal to the optical axis, independently of the particle concentration and size, also for subwavelength particles. It also provides the velocity distribution of the fluid over the entire sample thickness. The method has been quantitatively tested by using the motions of rigid diffusers and applied for mapping the flow of a confined fluid.
Thermomigration in eutectic SnPb alloy
Authors: Chuang Y. C. , Liu C. Y.
Published: May 2006

The thermomigration (TM) behavior in eutectic SnPb alloy was observed under a constant thermal gradient of 1000°C∕cm. Pb phase was depleting in the hot side, so Pb atom should be the dominant migration species in the current studied conditions. By estimating the depletion atomic volume in the hot side, TM atomic flux in SnPb was estimated to be 7.02×1013atoms∕cm2s. The important TM parameter, the molar heat flux (Q*), of eutectic SnPb alloy was obtained and found to be 22.16kJ∕mole.
Role of oxygen vacancy in HfO2∕SiO2∕Si(100) interfaces
Authors: Cho Deok-Yong , Oh S.-J. , Chang Y. J. , Noh T. W. , Jung Ranju , Lee Jae-Cheol
Published: May 2006

We have investigated the interface states in HfO2∕SiO2∕Si(100) systems that were prepared by using the in situ pulsed laser deposition technique. X-ray photoelectron spectroscopy data revealed that when the HfO2 film thickness exceeds 11Å, the film composition undergoes a systematic change from Hf silicate to oxygen-deficient HfOx<2. Furthermore, we determined that the evolution of the interface states clearly depends on the oxygen condition applied during the film growth and that the oxygen vacancy is an important parameter for Hf silicate formation.
Energetics at Au top and bottom contacts on conjugated polymers
Authors: Osikowicz W. , de Jong M. P. , Braun S. , Tengstedt C. , Fahlman M. , Salaneck W. R.
Published: May 2006

Photoelectron spectroscopy was employed to examine the energetics, and therefore charge injection barriers, at top and bottom contact configurations of gold and conjugated polymers, i.e., polymer spin coated on gold and vapor-deposited gold on polymer interfaces. Very similar results are obtained for both ex situ (contaminated) and in situ (clean) prepared interfaces: a 0.7–0.8eV decrease in the vacuum energy levels is consistently observed as compared to bare polycrystalline gold. These observations are explained by changes of the metal work function upon contacting either polymers or contaminants, associated with the reduction of the electron density tail that extends outside the metal surface.
Stimulated resonance Raman scattering from dye-doped polymer waveguides
Authors: Sakata Isao , Fujimoto Shuhei , Yanagi Hisao
Published: May 2006

We have investigated stimulated resonance Raman scattering (SRRS) from dye-doped polymer thin film waveguides. 1,4-bis[2-[N,N-di(p-totyl)amino]phenyl]vinyl]benzene (DADSB) was used as a dye doped in a spin-coated film of poly(vinyl-pyrrolidone) (PVP). Under optical pumping at the absorption edge of DADSB, a very narrow line (full width at half maximum ∼0.5nm) was observed only in the spectral region where the amplified spontaneous emission (ASE) band appeared. This emission line was assigned to SRRS with a Raman shift of 1600cm−1. The threshold excitation energy for this SRRS is higher than that of the ASE, but the slope efficiency of the SRRS was higher than that of the ASE. The polarization-dependent intensity revealed that the SRRS was propagated by the transverse electric mode in the thin film waveguide as same as the ASE.
Light chain inclusion permits terminal B cell differentiation and does not necessarily result in autoreactivity
Authors: Sirac C. , Carrion C. , Duchez S. , Comte I. , Cogné M.
Published: May 2006

Mice in which the Jκ cluster was replaced with a VκJκ rearranged gene were studied. More than 90% of B cells from homozygous mutant mice expressed the transgenic κ chain but showed a slightly reduced level of κ transcripts compared with WT B lymphocytes. Light chain inclusion was apparent in 10% of B cells from these mice and raised 25% in hemizygous mice with a still lower expression of the knockin κ chain. Beyond the rules of clonal selection, peripheral B cells developed in such animals, with included cells being activated and differentiating into class-switched or antibody-secreting cells. The high amount of included mature B cells was associated with an increase of hybrid κ/λ immunoglobulins but not with the increased prevalence of autoantibodies. Altogether, these data suggest that light chain exclusion prevalent in normal B cells mostly results from ordered rearrangements and stochastic mechanisms but is neither tightly ensured by a stringent cell selection process nor absolutely required for normal B cell function.