bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Satellite-Based Precipitation Observation in Improving the Parameterization of Canopy Hydrological Processes in Land Surface Models
Authors: Wang Dagang , Wang Guiling , Anagnostou Emmanouil N.
Published: November 2005

Precipitation exhibits significant spatial variability at scales much smaller than the typical size of climate model grid cells. Neglecting such subgrid-scale variability in climate models causes unrealistic representation of land–atmosphere flux exchanges. It is especially problematic over densely vegetated land. This paper addresses this issue by incorporating satellite-based precipitation observations into the representation of canopy interception processes in land surface models. Rainfall data derived from passive microwave (PM) observations are used to obtain realistic estimates of 1) conditional mean rain rates, which together with the modeled rain rate are used to estimate the rainfall coverage fraction at each model grid cell in this study, and 2) the probability density function (pdf) of rain rates within the rain-covered areas. Both of these properties significantly impact the land–atmosphere water vapor exchanges. Based on the above information, a statistical–dynamical approach is taken to incorporate the representation of precipitation subgrid variability into canopy interception processes in land surface models. The results reveal that incorporation of precipitation subgrid variability significantly alters the partitioning between runoff and total evapotranspiration as well as the partitioning among the three components of evapotranspiration (i.e., canopy interception loss, ground evaporation, and plant transpiration). This further influences soil water, surface temperature, and surface heat fluxes. It is shown that the choice of the rain-rate pdf within rain-covered areas has an effect on the model simulation of land–atmosphere flux exchanges. This study demonstrates that land surface and climate models can substantially benefit from the fine-resolution remotely sensed rainfall observations.
AGCM Biases in Evaporation Regime: Impacts on Soil Moisture Memory and Land–Atmosphere Feedback
Authors: Mahanama Sarith P. P. , Koster Randal D.
Published: November 2005

Because precipitation and net radiation in an atmospheric general circulation model (AGCM) are typically biased relative to observations, the simulated evaporative regime of a region may be biased, with consequent negative effects on the AGCM’s ability to translate an initialized soil moisture anomaly into an improved seasonal prediction. These potential problems are investigated through extensive offline analyses with the Mosaic land surface model (LSM). The LSM was first forced globally with a 15-yr observation-based dataset. The simulation was then repeated after imposing a representative set of GCM climate biases onto the forcings—the observational forcings were scaled so that their mean seasonal cycles matched those simulated by the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1; NASA Global Modeling and Assimilation Office) AGCM over the same period. The AGCM’s climate biases do indeed lead to significant biases in evaporative regime in certain regions, with the expected impacts on soil moisture memory time scales. Furthermore, the offline simulations suggest that the biased forcing in the AGCM should contribute to overestimated feedback in certain parts of North America—parts already identified in previous studies as having excessive feedback. The present study thus supports the notion that the reduction of climate biases in the AGCM will lead to more appropriate translations of soil moisture initialization into seasonal prediction skill.
Atmospheric Moisture Transport over the United States and Mexico as Evaluated in the NCEP Regional Reanalysis
Authors: Mo Kingtse C. , Chelliah Muthuvel , Carrera Marco L. , Higgins R. Wayne , Ebisuzaki Wesley
Published: November 2005

The large-scale atmospheric hydrologic cycle over the United States and Mexico derived from the 23-yr NCEP regional reanalysis (RR) was evaluated by comparing the RR products with satellite estimates, independent sounding data, and the operational Eta Model three-dimensional variational data assimilation (3DVAR) system (EDAS).

In general, the winter atmospheric transport and precipitation are realistic. The climatology and interannual variability of the Pacific, subtropical jet streams, and low-tropospheric moisture transport are well captured. During the summer season, the basic features and the evolution of the North American monsoon (NAM) revealed by the RR compare favorably with observations. The RR also captures the out-of-phase relationship of precipitation as well as the moisture flux convergence between the central United States and the Southwest. The RR is able to capture the zonal easterly Caribbean low-level jet (CALLJ) and the meridional southerly Great Plains low-level jet (GPLLJ). Together, they transport copious moisture from the Caribbean to the Gulf of Mexico and from the Gulf of Mexico to the Great Plains, respectively. The RR systematically overestimates the meridional southerly Gulf of California low-level jet (GCLLJ). A comparison with observations suggests that the meridional winds from the RR are too strong, with the largest differences centered over the northern Gulf of California. The strongest winds over the Gulf in the RR extend above 700 hPa, while the operational EDAS and station soundings indicate that the GCLLJ is confined to the boundary layer.
The role of lifestyle interventions and weight management in schizophrenia
Authors: Bushe Chris , Haddad Peter , Peveler Robert , Pendlebury John
Published: November 2005

The recognition that schizophrenia is associated with metabolic comorbidity and a subsequent greater risk of cardiovascular events compared to the general population has led to attempts to reduce this metabolic burden. Increased weight, and smoking rates combined with less exercise and poor dietary choices, have led to a variety of behavioural programmes and pharmacological agents being evaluated with the aim of improving lifestyle and managing weight. Adjunctive pharmacological strategies for weight management have not been shown to be consistently effective and remain contraindicated in many schizophrenia subjects. However some novel compounds with recent promising data suggest that research should not be abandoned. In contrast a variety of behavioural interventions have shown a consistent degree of success not only with weight management but also in achieving lifestyle changes. Many reported data-sets are naturalistic or open-label indicating that there is a difficulty in performing traditional randomized controlled studies in this area. The long-term naturalistic studies and holistic approaches show that weight management and significant lifestyle changes are attainable goals in schizophrenia patients. Weight management and lifestyle advice should be routinely offered to all schizophrenia subjects.
Development of a Characterization Mold to Measure the Transverse Thermal Conductivity of a Composite Material by Inverse Analysis
Authors: Assaf B. , Menge H. , Sobotka V. , Trochu F.
Published: November 2005

In the present work, the transverse thermal conductivity of a composite material is determined by inverse analysis of the heat conduction phenomenon. Knowing the evolution of boundary conditions in time, i.e., the bottom and top surface temperatures of a specific sample, the thermal conductivity can be deduced from transient temperature measurements at three given positions through the thickness of the part. Starting from an initial estimate of thermal conductivity, the inverse method begins by solving the direct problem, i.e., the heat equation. The solution gives the transient temperature field everywhere in the composite sample. Calculated temperatures are then compared with transient experimental measurements based on a criterion evaluating the integral in time of the square of the distance between the measured and predicted temperatures. Conductivity is modified iteratively so as to minimize this criterion until the desired accuracy is achieved. The inverse methodology is tested in this article for a composite part made out of unsaturated polyester resin and unidirectional glass fibers. A special multifunctional mold was designed to produce the composite test plates by the Resin Transfer Molding Process (RTM) and at the same time, measure the transverse thermal conductivity as a function of time and resin degree of polymerization. The mold has an adjustable cavity depth to accommodate various experimental configurations and allows easy testing of a series of different fiber volume contents. It is equipped with controlled heating and cooling devices. Numerical simulations were performed to determine the dimensions of the mold and to optimize the positions of temperature and pressure sensors.
The Effect of Medication Reviews in a Rural Community Pharmacy Assistance Program: The Cenla Medication Access Program
Authors: Lefante John J. , Harmon Gary N. , Roy Wendy , Fontenot Sue , Brown Kevin , Webber Larry
Published: November 2005

The purpose of this article is to determine the effect of mediing equations were used to assess change in PURPOSE, USE,cation reviews on patient understanding of and compliance COMPLIANCE, INTERACTION, and REACTION over time. to medications for participants in the Cenla Medication Ac All effects were adjusted for differences in age, race, gender, cess Program (CMAP). A sample of 844 individuals with a to the number of years of education, total number of medicatal of 2013 reviews over a period of 6 months to 1 year protions per patient, and the patient’s primary diagnosis. Signifiduced 5 outcome variables: the percentage of the total cant increases were observed for PURPOSE, USE, and number of drugs the patient understands the purpose of COMPLIANCE. A significant decrease was observed for (PURPOSE), understands the proper use of (USE), and is INTERACTION. No significant difference in REACTION was compliant with (COMPLIANCE) and the percentage of paobserved over time. CMAP has seen increases in patient untients that experienced any drug-drug or drug-disease interderstanding and compliance, as well as a decrease in drug-actions (INTERACTION) or any adverse reactions drug and drug-disease interactions through the first year of (REACTION). Mixed-effects models and generalized estimat medication reviews.
Targeting receptor kinases by a novel indolinone derivative in multiple myeloma: abrogation of stroma-derived interleukin-6 secretion and induction of apoptosis in cytogenetically defined subgroups
Authors: Bisping Guido , Kropff Martin , Wenning Doris , Dreyer Britta , Bessonov Sergey , Hilberg Frank , Roth Gerald J. , Munzert Gerd , Stefanic Martin , Stelljes Matthias , Scheffold Christian , Müller-Tidow Carsten , Liebisch Peter , Lang Nicola , Tchinda Jöelle , Serve Hubert L. , Mesters Rolf M. , Berdel Wolfgang E. , Kienast Joachim
Published: November 2005

In multiple myeloma (MM), both vascular endothelial (VEGF) and basic fibroblast growth factor (bFGF) promote tumor growth and survival. We have used the novel indolinone BIBF 1000 to study effects of simultaneous inhibition of VEGF, FGF and transforming growth factor-β on MM cells and their interactions with bone marrow stroma cells (BMSCs). Both, in the absence and presence of myeloma-stroma cell contacts, BIBF 1000 abrogated BMSC-derived secretion of interleukin-6 (IL-6). In addition, BIBF 1000 directly induced apoptosis in t(4;14)–positive cell lines as well as in CD138+ marrow cells from patients with t(4;14) myeloma. To a similar extent, BIBF 1000 induced apoptosis in MM.1S and MM.1R cells carrying the translocation t(14;16). In case of MM.1S and other dexamethasone-sensitive t(14;16) cell lines, BIBF 1000 and dexamethasone had additive proapoptotic effects. Induction of apoptosis by BIBF 1000 was associated with inhibition of the mitogen-activated protein kinases (MAPK) pathway in t(4;14) and inhibition of the phosphatidyl-inositol-3 kinase/AKT pathway in t(14;16) cells. Apoptotic effects did not occur in t(4;14)–or t(14;16)–positive MM cells carrying n- or k-Ras mutations. The data provide the rationale for clinical evaluation of this class of targeted kinase inhibitors in MM with focus on defined cytogenetic subgroups.
Human embryonic stem cell–derived hematopoietic cells are capable of engrafting primary as well as secondary fetal sheep recipients
Authors: Narayan A. Daisy , Chase Jessica L. , Lewis Rachel L. , Tian Xinghui , Kaufman Dan S. , Thomson James A. , Zanjani Esmail D.
Published: November 2005

The human/sheep xenograft model has proven valuable in assessing the in vivo hematopoietic activity of stem cells from a variety of fetal and postnatal human sources. CD34+/lineage- or CD34+/CD38- cells isolated from human embryonic stem cells (hESCs) differentiated on S17 feeder layer were transplanted by intraperitoneal injections into fetal sheep. Chimerism in primary transplants was established with polymerase chain reaction (PCR) and flow cytometry of bone marrow and peripheral blood samples. Whole bone marrow cells harvested from a primary recipient were transplanted into a secondary recipient. Chimerism was established as described before. This animal was stimulated with human GM-CSF, and an increase in human hematopoietic activity was noted by flow cytometry. Bone marrow aspirations cultured in methylcellulose generated colonies identified by PCR to be of human origin. We therefore conclude that hESCs are capable of generating hematopoietic cells that engraft primary recipients. These cells also fulfill the criteria for long-term engrafting hematopoietic stem cells as demonstrated by engraftment and differentiation in the secondary recipient.
A WAVE2-Abi1 complex mediates CSF-1-induced F-actin-rich membrane protrusions and migration in macrophages
Authors: Abou Kheir Wassim , Gevrey Jean-Claude , Yamaguchi Hideki , Isaac Beth , Cox Dianne
Published: November 2005

Colony-stimulating factor 1 (CSF-1) is an important physiological chemoattractant for macrophages. The mechanisms by which CSF-1 elicits the formation of filamentous actin (F-actin)-rich membrane protrusions and induces macrophage migration are not fully understood. In particular, very little is known regarding the contribution of the different members of the Wiskott-Aldrich Syndrome protein (WASP) family of actin regulators in response to CSF-1. Although a role for WASP itself in macrophage chemotaxis has been previously identified, no data was available regarding the function of WASP family verprolin-homologous (WAVE) proteins in this cell type. We found that WAVE2 was the predominant isoform to be expressed in primary macrophages and in cells derived from the murine monocyte/macrophage RAW264.7 cell line (RAW/LR5). CSF-1 treatment of macrophages resulted in WAVE2 accumulation in F-actin-rich protrusions induced by CSF-1. Inhibition of WAVE2 function by expressing a dominant-negative mutant or introducing anti-WAVE2 antibodies in RAW/LR5 cells, as well as reduction of endogenous WAVE2 expression by RNA-mediated interference (RNAi), resulted in a significant reduction of CSF-1-elicited F-actin protrusions. WAVE2 was found in a protein complex together with Abelson kinase interactor 1 (Abi1) in resting or stimulated cells. Both WAVE2 and Abi1 were recruited to and necessary for the formation of F-actin protrusions in response to CSF-1. Reducing the levels of WAVE2, directly or by targeting Abi1, resulted in an impaired cell migration to CSF-1. Altogether these data identify a WAVE2-Abi1 complex crucial for the normal actin cytoskeleton reorganization and migration of macrophages in response to CSF-1.
Involvement of Rac in actin cytoskeleton rearrangements induced by MIM-B
Authors: Bompard Guillaume , Sharp Stewart J. , Freiss Gilles , Machesky Laura M.
Published: November 2005

Numerous scaffold proteins coordinate signals from the environment with actin-based protrusions during shape change and migration. Many scaffolds integrate signals from Rho-family GTPases to effect the assembly of specific actin structures. Here we investigate the mechanism of action MIM-B (missing in metastasis-B) on the actin cytoskeleton. MIM-B binds actin monomer through a WASP homology 2 motif, bundles actin filaments via an IRSp53/MIM domain, and is a long isoform of MIM, a proposed metastasis suppressor. We analysed the activity of MIM-B toward the actin cytoskeleton as well as its potential link to cancer metastasis. Endogenous MIM-B protein is widely expressed and its expression is maintained in various metastatic cell lines. MIM-B induces lamellipodia-like actin-rich protrusions. The IRSp53/MIM domain of MIM-B, as well as Rac activity are required to induce protrusions, but not the WASP homology 2 motif. MIM-B binds and activates Rac via its IRSp53/MIM domain, but this is not sufficient to induce lamellipodia. Finally, our data revealed that actin bundling and Rac-binding properties of MIM-B are not separable. Thus, MIM-B is unlikely to be a metastasis suppressor but acts as a scaffold protein that interacts with Rac, actin and actin-associated proteins to modulate lamellipodia formation.
In smooth muscle, FK506-binding protein modulates IP3 receptor-evoked Ca2+ release by mTOR and calcineurin
Authors: MacMillan Debbi , Currie Susan , Bradley Karen N. , Muir Thomas C. , McCarron John G.
Published: November 2005

Ca2+ release from the sarcoplasmic reticulum (SR) by the IP3 receptors (IP3Rs) crucially regulates diverse cell signalling processes from reproduction to apoptosis. Release from the IP3R may be modulated by endogenous proteins associated with the receptor, such as the 12 kDa FK506-binding protein (FKBP12), either directly or indirectly by inhibition of the phosphatase calcineurin. Here, we report that, in addition to calcineurin, FKPBs modulate release through the mammalian target of rapamycin (mTOR), a kinase that potentiates Ca2+ release from the IP3R in smooth muscle. The presence of FKBP12 was confirmed in colonic myocytes and co-immunoprecipitated with the IP3R. In aortic smooth muscle, however, although present, FKBP12 did not co-immunoprecipitate with IP3R. In voltage-clamped single colonic myocytes rapamycin, which together with FKBP12 inhibits mTOR (but not calcineurin), decreased the rise in cytosolic Ca2+ concentration ([Ca2+]c) evoked by IP3R activation (by photolysis of caged IP3), without decreasing the SR luminal Ca2+ concentration ([Ca2+]l) as did the mTOR inhibitors RAD001 and LY294002. However, FK506, which with FKBP12 inhibits calcineurin (but not mTOR), potentiated the IP3-evoked [Ca2+]c increase. This potentiation was due to the inhibition of calcineurin; it was mimicked by the phosphatase inhibitors cypermethrin and okadaic acid. The latter two inhibitors also prevented the FK506-evoked increase as did a calcineurin inhibitory peptide (CiP). In aortic smooth muscle, where FKBP12 was not associated with IP3R, the IP3-mediated Ca2+ release was unaffected by FK506 or rapamycin. Together, these results suggest that FKBP12 has little direct effect on IP3-mediated Ca2+ release, even though it is associated with IP3R in colonic myocytes. However, FKBP12 might indirectly modulate Ca2+ release through two effector proteins: (1) mTOR, which potentiates and (2) calcineurin, which inhibits Ca2+ release from IP3R in smooth muscle.
Secrets of a double agent: CDK7 in cell-cycle control and transcription
Authors: Fisher Robert P.
Published: November 2005

In metazoans, cyclin-dependent kinase 7 (CDK7) has essential roles in both the cell-division cycle and transcription, as a CDK-activating kinase (CAK) and as a component of the general transcription factor TFIIH, respectively. Controversy over its double duty has been resolved, but questions remain. First, how does CDK7 achieve the dual substrate specificity necessary to perform both roles? Second, is there a deeper connection implied by the dichotomy of CDK7 function, for example similar mechanisms controlling cell division and gene expression, and/or actual coordination of the two processes? Enzymological studies have revealed solutions to the unusual substrate recognition problem, and there is evidence that the distinct functions of CDK7 can be regulated independently. Finally, despite divergence in their wiring, the CAK-CDK networks of budding yeast, fission yeast and metazoans all link transcriptional regulation with operation of the cell-cycle machinery. This connection might help to ensure that mRNAs encoding effectors of cell division are expressed at the right time in the cycle.
Integrated Lot Sizing in Serial Supply Chains with Production Capacities
Authors: van Hoesel Stan , Romeijn H. Edwin , Morales Dolores Romero , Wagelmans Albert P. M.
Published: November 2005

We consider a model for a serial supply chain in which production, inventory, and transportation decisions are integrated in the presence of production capacities and concave cost functions. The model we study generalizes the uncapacitated serial single-item multilevel economic lot-sizing model by adding stationary production capacities at the manufacturer level. We present algorithms with a running time that is polynomial in the planning horizon when all cost functions are concave. In addition, we consider different transportation and inventory holding cost structures that yield improved running times: inventory holding cost functions that are linear and transportation cost functions that are either linear, or are concave with a fixed-charge structure. In the latter case, we make the additional common and reasonable assumption that the variable transportation and inventory costs are such that holding inventories at higher levels in the supply chain is more attractive from a variable cost perspective. While the running times of the algorithms are exponential in the number of levels in the supply chain in the general concave cost case, the running times are remarkably insensitive to the number of levels for the other two cost structures.
Lower Bounds for the Capacitated Facility Location Problem Based on Column Generation
Authors: Klose Andreas , Drexl Andreas
Published: November 2005

The capacitated facility location problem (CFLP) is a well-known combinatorial optimization problem with applications in distribution and production planning. A variety of lower bounds based on Lagrangean relaxation and subgradient optimization has been proposed for this problem. However, information about a primal (fractional) solution can be important to solve large or difficult problem instances. Therefore, we study various approaches for solving the master problems exactly. The algorithms employ different strategies for stabilizing the column-generation process. Furthermore, a new lower bound for the CFLP based on partitioning the plant set and employing column generation is proposed. Computational results are reported for a set of large problem instances.
Accounting Conservatism and Managerial Incentives
Authors: Kwon Young K.
Published: November 2005

There are two sources of agency costs under moral hazard: (1) distortions in incentive contracts and (2) implementation of suboptimal decisions. In the accounting literature, the relation between conservative accounting and agency costs of type (1) has received considerable attention (cf. Watts 2002). However, little appears to be known about the effects of accounting conservatism on agency costs of type (2) or trade-offs between agency costs of types (1) and (2). The purpose of this study is to examine this void. In a principal-agent setting in which the principal motivates the agent to expend effort using accounting earnings, this study shows that accounting earnings become more useful for reducing agency costs of type (2) when measured conservatively than when measured aggressively. Combined with the result in Kwon et al. (2001) that agency costs of type (1) decrease with accounting conservatism, this analysis suggests that conservative accounting enhances the incentive value of accounting signals with respect to both types of agency costs.
Antecedents and Consequences of Group Potency: A Study of Self-Managing Service Teams
Authors: de Jong Ad , de Ruyter Ko , Wetzels Martin
Published: November 2005

This paper proposes and tests a model of antecedents and consequences of group potency in self-managing teams in retail banking. Based on data collected from boundary-spanning service employees organized in 60 teams and their customers, our findings reveal a significant positive impact of group potency on customer-perceived service quality and a negative effect on service profitability. In addition, we find that team consensus regarding group potency positively moderates the effects of group potency, so that for teams with higher levels of potency consensus, the positive impact of group potency on customer-perceived service quality is stronger, whereas the negative impact of group potency on service productivity is weaker. Furthermore, we find significant positive effects of management and interteam support and functional diversity as well as a significant negative effect of team tenure on individual team member beliefs of group potency. Finally, social support consensus moderates the effects of management support, interteam support, and team tenure on group potency, so that the effects of these antecedents are weaker for teams with higher levels of social support consensus. Thus, we conclude that team confidence consensus increases the positive impact of group potency on customer perceptions of service quality and decreases the negative impact on profitability. Thus, team-member perceptual agreement on their team's potency should be stimulated.
Mikrogehäuste mediengetrennte Silizium-Druck- und Differenzdrucksensoren für industrielle Anwendungen (Silicon-based Microsensors for Pressure and Differential Pressure with Media Separation for Industrial Applications)
Authors: Wohlgemuth Christian , Sindlinger Stefan , Werthschützky Roland , Thiele Peter
Published: November 2005

Die mediengetrennte Gehäusung piezoresistiver Drucksensoren ist gegenüber den Kosten für das Silizium-Messelement unverhältnismäßig teuer. Der Einsatz neuer Werkstoffe und Fertigungsverfahren ermöglicht es, die Sensoren zu miniaturisieren, Kosten einzusparen und eine mikrocontrollerbasierte Fehlerkorrektur zu integrieren.
Effect of Sample Size on the Solidification Temperature and Microstructure of SnAgCu Near Eutectic Alloys
Authors: Kinyanjui R. , Lehman L.P. , Zavalij L. , Cotts E.
Published: November 2005

The degree of undercooling of Sn in near eutectic, SnAgCu solder balls upon cooling at a rate of 1 °C/s from the melt was examined and found to increase linearly with inverse nominal sample diameter (for balls of radius between 100 and 1000 μm). The mean undercooling for SnAgCu solder balls in a flip chip assembly was 62 °C. The microstructures of these different samples were examined by means of scanning electron microscopy. The Sn dendrite arm width was observed to monotonically increase with ball diameter, indicating a possible dependence of the mechanical response of such solder balls upon size.
Significant Increment of Photoluminescence Quantum Yield by Efficiently Prohibiting Fluorescence Quenching in Erbium(III) Organic Complexes
Authors: Li Yigang , Yang Hong , He Zian , Liu Liying , Wang Wencheng , Li Fuyou , Xu Lei
Published: November 2005

A systematic investigation and comparison of the photoluminescence (PL) quantum yields of six erbium(III) organic complexes are reported. We demonstrated that the PL quantum yield could be significantly improved by getting rid of OH and CH groups in the complexes. Moreover, perfluooctanoic acid with neither OH nor CH groups was used as a ligand to form complex with Er3+. The quantum yield of the newly synthesized erbium(III) complex was found to be as high as 2%, 100 times higher than ever reported.
Synthesis of Highly Porous Aluminas Mediated by Cationic Surfactant: Structural and Textural Properties
Authors: Toledo J.A. , Bokhimi X. , Lopez C. , Angeles C. , Hernandez F. , Fripiat J.J.
Published: November 2005

The cationic surfactant cetyltrimetylammonium bromide was used to synthesize mesostructured γ–Al2O3. The effects of the surfactant concentration and of the sol aging (at 95 °C for 24 h) were studied by x-ray powder diffraction, nuclear magnetic resonance, transmission electron microscopy, and analysis of the low-temperature nitrogen adsorption-desorption isotherms. Mesostructured alumina with wormhole morphology and amorphous walls was obtained through the precipitation by ammonium hydroxide of a 0.1 M aluminum nitrate aqueous solution in presence of 0.1 M surfactant. The pore size was smaller than 5 nm. After digesting the milky suspension under atmospheric pressure at 95 °C, a crystallized boehmite-surfactant phase, with fiber morphology, is formed which at 550 and 700 °C is transformed into a highly porous γ−Al2O3. A similar evolution was observed using 0.01 M CTAB solution and aging. Pore volume up to 1.1 cm3/g and pore size up to 16 nm were obtained. Without surfactant, the same aging treatment led to aggregated fibers: the pore size is less than 8 nm and the pore volume is smaller than 0.6 cm3/g. The γ-alumina surface area is determined mainly by the organization generated by the surfactant and to a lesser extent by the boehmite precursor particle size. From the point of view of catalyst preparation, the surfactant at the concentration of 0.01 M in 0.1 M aluminum nitrate and the aging treatment in solution play a beneficial role.
Flame Synthesis of Y2O3:Eu Nanophosphors Using Ethanol as Precursor Solvents
Authors: Qin Xiao , Ju Yiguang , Bernhard Stefan , Yao Nan
Published: November 2005

Y2O3:Eu nanophosphors were prepared by flame synthesis using ethanol or water as precursor solutions. The effects of precursor solvents and flame temperature on particle size, morphology, and photoluminescence intensity were investigated. The results showed that flame synthesis using ethanol solution could produce nanoparticles with better homogeneity, smoother surface structure, and stronger photoluminescence intensity than using water. It was found that the concentration quenching limit of the as-prepared nanophosphors from both ethanol and water solution was 18 mol% Eu, which is higher than the reported limit at similar particle size. The x-ray diffraction (XRD) spectra showed that the ethanol precursor solvent produced monoclinic phase Y2O3:Eu nanoparticles at a lower flame temperature than previously reported. It was also shown that the particle size could be controlled by varying the precursor concentration and flame temperature.
Assessment of Chemical Solution Synthesis and Properties of Gd2Zr2O7 Thin Films as Buffer Layers for Second-Generation High-Temperature Superconductor Wires
Authors: Aytug T. , Paranthaman M. , Leonard K.J. , Zhai H.Y. , Bhuiyan M.S. , Payzant E.A. , Goyal A. , Sathyamurthy S. , Beach D.B. , Martin P.M. , Christen D.K. , Li X. , Kodenkandath T. , Schoop U. , Rupich M.W. , Smith H.E. , Haugan T. , Barnes P.N.
Published: November 2005

Chemical solution processing of Gd2Zr2O7 (GZO) thin films via sol-gel and metalorganic decomposition (MOD) precursor routes have been studied on textured Ni-based tape substrates. Even though films processed by both techniques showed similar property characteristics, the MOD-derived samples developed a high degree of texture alignment at significantly lower temperatures. Both precursor chemistries resulted in exceptionally dense, pore-free, and smooth microstructures, reflected in the cross-sectional and plan-view high-resolution scanning and transmission electron microscopy studies. On the MOD GZO buffered Ni–3at.% W (Ni–W) substrates with additional CeO2/YSZ sputtered over layers, a 0.8-μm-thick YBa2Cu3O7−δ (YBCO) film, grown by an ex situ metalorganic trifluoroacetate precursor method, yielded critical current, Ic (77 K, self-field), of 100 A/cm width. Furthermore, using pulsed-laser deposited YBCO films, a zero-field superconducting critical current density, Jc (77 K), of 1 × 106 A/cm2 was demonstrated on an all-solution, simplified CeO2(MOD)/GZO(MOD)/Ni–W architecture. The present study establishes GZO buffers as a candidate material for low-cost, all-solution coated conductor fabrication.
Synthesis and Characterization of Copper Hydroxide Acetate With a Layered Discoid Crystal
Authors: Kozai Naofumi , Mitamura Hisayoshi , Fukuyama Hiroyasu , Esaka Fumitaka , Komarneni Sridhar
Published: November 2005

Titration of copper acetate solution with a dilute NaOH solution to pH 6.5 and subsequent aging at 313 K yielded copper hydroxide acetate with an analytical composition of Cu2(OH)3.1(OCOCH3)0.9nH2O (n ∼ 0.7) and layered discoid crystals. The chemical composition, structure, and holistic trend in thermal behavior are similar to those of the previously known Cu2(OH)3(OCOCH3)H2O phase with layered rectangular crystals. The most obvious difference between the two compounds is morphology of the crystals. The other major differences are found in stability of bonding of the interlayer acetate ions to solid phase and behavior in anion-containing solutions. The interlayer acetate ions in the present compound begin to be dissociated from the solid phase at ∼343 K while those in the previous compound are not dissociated below 383 K. The reaction of the present compound is topotactic in Cl− and NO3− aqueous solutions but reconstructive in a SO42− aqueous solution while the reaction of the previous compound in those solutions is topotactic.
Controlled Growth of Gold Nanoparticles on Silica Nanowires
Authors: LaLonde Aaron D. , Norton M. Grant , Zhang Daqing , Gangadean Devananda , Alkhateeb Abdullah , Padmanabhan Radhakrishnan , McIlroy David N.
Published: November 2005

Production of gold nanoparticles with the specific goal of particle size control has been investigated by systematic variation of chamber pressure and substrate temperature. Gold nanoparticles have been synthesized on SiO2 nanowires by plasma-enhanced chemical vapor deposition. Determination of particle size and particle size distribution was done using transmission electron microscopy. Average nanoparticle diameters were between 4 and 12 nm, with particle size increasing as substrate temperature increased from 573 to 873 K. A bimodal size distribution was observed at temperatures ≥723 K indicating Ostwald ripening dominated by surface diffusion. The activation energy for surface diffusion of gold on SiO2 was determined to be 10.4 kJ/mol. Particle sizes were found to go through a maximum with increases in chamber pressure. Competition between diffusion within the vapor and dissociation of the precursor caused the pressure effect.
Aluminum Nitride Tunnel Barrier Formation with Low-Energy Nitrogen Ion Beams
Authors: Kaul Anupama B. , Kleinsasser Alan W. , Bumble Bruce , LeDuc Henry G. , Lee Karen A.
Published: November 2005

We report the use of low-energy nitrogen ion beams to form ultra-thin (<2 nm) layers of AlNx to act as tunnel barriers in Nb/Al–AlNx/Nb Josephson junctions. We fabricated reproducible, high-quality devices with independent control of the ion energy and dose, enabling exploration of a wide parameter space. Critical current density Jc ranged from 550 to 9400 A/cm2 with subgap-to-normal resistance ratios from 50 to 12.6. The spatial variation of ion-current density was roughly correlated with Jc over a large-area on a Si substrate. The junctions were stable on annealing up to temperatures of at least 200 °C. This technique could be applied to form other metal nitrides at room temperature for device applications where a high degree of control is desired.
Phase Stability, Phase Transformations, and Elastic Properties of Cu6Sn5: Ab initio Calculations and Experimental Results
Authors: Ghosh G. , Asta M.
Published: November 2005

Among many Sn-based intermetallics, Cu6Sn5(η and η′) is ubiquitous in modern solder interconnects. Using the published structural models of η and η′ and also related structures, the total energies and equilibrium cohesive properties are calculated from first-principles employing electronic density-functional theory, ultrasoft pseudopotentials, and both the local density approximation (LDA) and the generalized gradient approximation (GGA) for the exchange-correlation energy. The accuracy of our calculations is assessed through comparisons between theoretical results and experimental measurements for lattice parameters, elastic properties, and formation and transformation energies. The ambient-temperature experimental lattice constants of η and η′ are found to lie between the LDA and GGA level calculated zero-temperature lattice constants. The Wyckoff positions in the structural models of η and η′ agree very well with the ab initio results. The calculated formation energy of η′ lies between −3.2 and −4.0 kJ/mol, which is more positive by about 3 to 4 kJ/mol compared to reported experimental data obtained by solution calorimetry. Our systematic differential scanning calorimetry (DSC) experiments show that the η′ → η transformation enthalpy is 438 ± 18 J/mol, which is about 66% higher than the literature value. In view of our DSC results on heating and cooling, the nature of η′ → η and η → η′ is discussed. Our experimental bulk modulus of η and η′, and the heat of η′ → η transformation agree very well with the ab initio total energy calculations at the GGA level. Based on these results, we conclude that other isotropic elastic moduli (Young’s modulus, shear, and Poissons ratio) of η and η′ phases measured by pulse-echo technique are representative of their actual properties. The scatter in experimental elastic constants in the literature may be attributed to various factors, such as the measurement technique (pulse-echo versus nanoindentation), type of specimen (bulk, Cu6Sn5-layer in diffusion couple, thin-film), and anisotropy effects (particularly in Cu6Sn5-layer in diffusion couples).
Restructuring tungsten thin films into nanowires and hollow square cross-section microducts
Authors: Parthangal Prahalad M. , Cavicchi Richard E. , Montgomery Christopher B. , Turner Shirley , Zachariah Michael R.
Published: November 2005

We report on the growth of nanowires and unusual hollow microducts of tungsten oxide by thermal treatment of tungsten films in a radio frequency H2/Ar plasma at temperatures between 550 and 620 °C. Nanowires with diameters of 10–30 nm and lengths between 50 and 300 nm were formed directly from the tungsten film, while under certain specific operating conditions hollow microducts having edge lengths∼0.5 μm and lengths between 10 and 200 μm were observed. Presence of a reducing gas such as H2 was crucial in growing these nanostructures as were trace quantities of oxygen, which was necessary to form a volatile tungsten species. Preferential restructuring of the film surface into nanowires or microducts appeared to be influenced significantly by the rate of mass transfer of gas-phase species to the surface. Nanowires were also observed to grow on tungsten wires under similar conditions. A surface containing nanowires, annealed at 500 °C in air, exhibited the capability of sensing trace quantities of nitrous oxides (NOx).
Characterization of Highly-Oriented Ferroelectric PbxBa1−x TiO3 Thin Films Grown by Metalorganic Chemical Vapor Deposition
Authors: El-Naggar Mohamed Y. , Boyd David A. , Goodwin David G.
Published: November 2005

PbxBa1−xTiO3 (0.2 ⩽ x ⩽ 1) thin films were deposited on single-crystal MgO as well as amorphous Si3N4/Si substrates using biaxially textured MgO buffer templates, grown by ion beam-assisted deposition (IBAD). The ferroelectric films were stoichiometric and highly oriented, with only (001) and (100) orientations evident in x-ray diffraction (XRD) scans. Films on biaxially textured templates had smaller grains (60 nm average) than those deposited on single-crystal MgO (300 nm average). Electron backscatter diffraction (EBSD) has been used to study the microtexture on both types of substrates and the results were consistent with x-ray pole figures and transmission electron microscopy (TEM) micrographs that indicated the presence of 90° domain boundaries, twins, in films deposited on single-crystal MgO substrates. In contrast, films on biaxially textured substrates consisted of small single-domain grains that were either c or a oriented. The surface-sensitive EBSD technique was used to measure the tetragonal tilt angle as well as in-plane and out-of-plane texture. High-temperature x-ray diffraction (HTXRD) of films with 90° domain walls indicated large changes, as much as 60%, in the c and a domain fractions with temperature, while such changes were not observed for PbxBa1−xTiO3 (PBT) films on biaxially textured MgO/Si3N4/Si substrates, which lacked 90° domain boundaries.
Synthesis of Nitrogen-Doped Titanium Oxide Nanostructures Via a Surfactant-Free Hydrothermal Route
Authors: Rhee Chang Houn , Lee Jae Sung , Chung Soo Hyun
Published: November 2005

Nitrogen-doped titanium oxides nanostructures were synthesized by a new method proposed here from titanium oxysulfate precursor in a NH4OH solution under hydrothermal conditions without any extra templates as structure driving agents. The material synthesized with NH4OH was an ammonium titanate and showed curled nanosheets, nanofibers or nanorods morphologies depending on the molar ratio of NH4OH to titanium precursor and the hydrothermal temperature. The nanofibrous titanates had a high surface area over 500 m2 g−1 and a pore volume of 0.72 cm3 g−1. The calcination of as-synthesized material at 673 K produced a titanium oxynitride TiO2−xNx with anatase phase, which absorbed visible light. Ion exchange of ammonium ion of the titanate with sodium Na2Ti3O7−xNx enhanced the thermal stability of the titanate phase.
Preparation of Polymer-Covered Metal Nanorods and Metal Microcrystals by Intrinsic Two-Dimensional Crystalline Lattice Templating
Authors: Pavel Alexandru C. , Romanovicz Dwight K. , Yacaman Miguel J. , McDevitt John T.
Published: November 2005

Two-dimensional layered ceramics, highly anisotropic materials in terms of structure and properties, were used to produce polymer-covered metal nanorods and metal microcrystals. The procedure took advantage of the intrinsic planar, layered ordering of the metal cations suitable to be reduced and could be further used to engineer one-dimensional metal alloy nanostructures by appropriate doping of the initial layered ceramic lattice with suitable cationic species. The procedure involved the formation in an intermediate step of a polymer-intercalated ceramic nanocomposite, highly porous to the diffusion of the polymerizable reducing agent, pyrrole. Two structurally similar layered bismuthates, Bi2Sr2CaCu2O8+δand Bi6Sr2CaO12and a partially Rh-substituted ceramic, Bi4Rh2Sr2CaO12were used as the precursor layered ceramics and the reducible metal cations were Cu2+, Bi3+, and Rh3+, respectively. The formation of the polymer-covered metal nanorods and metal microcrystals took place at relatively high temperatures of reaction (325 °C) and long reaction times (10–12 days).
Uniaxial and biaxial mechanical behavior of human amnion
Authors: Oyen Michelle L. , Cook Robert F. , Stylianopoulos Triantafyllos , Barocas Victor H. , Calvin Steven E. , Landers Daniel V.
Published: November 2005

Chorioamnion, the membrane surrounding a fetus during gestation, is a structural soft tissue critical for maintaining a successful pregnancy and delivery. However, the mechanical behavior of this tissue membrane is poorly understood. The structural component of chorioamnion is the amnion sublayer, which provides the membrane’s mechanical integrity via a dense collagen network and is the focus of this investigation. Amnion uniaxial and planar equi-biaxial tension testing was performed using cyclic loading and stress-relaxation. Cyclic testing demonstrated dramatic energy dissipation in the first cycle followed by less hysteresis on subsequent cycles. Fractional energy dissipation per cycle was strain dependent, with greatest dissipation at small strain levels. Stress-relaxation testing demonstrated a level-dependent response and continued relaxation after long relaxation times. A nonlinear viscoelastic (separable) hereditary integral approach was inadequate to model the amnion response due to intrinsic coupling of the strain- and time-dependent responses.
Low Loss Dielectrics in Ba[(Mg1/3Ta2/3)1−xTix]O3 and Ba[(Mg1−xZnx)1/3Ta2/3]O3 Systems
Authors: Surendran Kuzhichalil Peethambaran , Sebastian Mailadil Thomas
Published: November 2005

The microwave dielectric properties of ceramics based on Ba[(Mg1/3Ta2/3)1−xTix]O3 (BMT-BT) and Ba[(Mg1−xZnx)1/3Ta2/3]O3 (BMT-BZT) were investigated as a function of composition x. In BMT-BT solid solution, the dielectric properties deteriorated with increasing concentration of Ti substitution at the B-site of BMT. A correlation was established between the quality factors of the solid solution phases and their tolerance factor. In BMT-BZT solid solution, where both the end compounds are ordered perovskites, the unit cell expands with increasing mole fraction of the Zn in Mg site of BMT while the dielectric constant increases monotonously from 24.8 (for BMT) to 29.7 (BZT). In BMT-BZT solid solution, the quality factor reaches a maximum (Qu·f = 109,900 GHz) for 60 mol/ of BZT.
Phase Equilibria in the Sn-Rich Corner of the Sn–Cu–Ni Ternary Alloy System at 240 °C
Authors: Li Chia-Ying , Duh Jenq-Gong
Published: November 2005

The interfacial reactions between solders and under bump metallization (UBM) have been of great interest recently in flip chip technology. Intermetallic compounds (IMCs), i.e., (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4, usually formed between solders and UBM. To fully understand the interfacial reactions and phase transformation phenomenon, a suitable phase diagram concerning solders, IMCs, and UBM materials is required. In particular, a Sn-rich phase region in the Sn–Cu–Ni ternary diagram is very critical in determining the concentration tendency of x and y values in (Ni1−x,Cux)3Sn4 and (Cu1−y,Niy)6Sn5 compounds. In this study, ternary Sn–Cu–Ni alloys were prepared and annealed at 240 °C. Three equilibrium phases, Sn, Ni3Sn4, and Cu6Sn5, were identified by x-ray diffraction analysis and also showed in backscattered electron imaging. Using electron probe microanalysis quantitative analysis, three acme compositions of the ternary region in the Sn–Cu–Ni isotherm near the Sn-rich corner were determined as 98.5 at.% Sn, (Ni0.80, Cu0.20)3Sn4 and (Cu0.59,Ni0.41)6Sn5. In addition, the solubility of Cu and Ni in (Ni,Cu)3Sn4 and (Cu,Ni)6Sn5 compounds was evaluated. Finally, the isothermal section of the ternary Sn–Cu–Ni system at 240 °C was proposed on the basis of experimental results in this study.
Wavelength Dependence of Crystallization of Alkoxy-Derived ZrO2 Thin Films Prepared by Ultraviolet Irradiation
Authors: Nishizawa Kaori , Miki Takeshi , Suzuki Kazuyuki , Kato Kazumi
Published: November 2005

Wavelength dependence was observed in the ultraviolet (UV) irradiation-assisted crystallization of alkoxy-derived ZrO2 thin films. The surface grains of thin films deposited on Si(100) substrates became enlarged by UV irradiation using an ultrahigh-pressure mercury lamp. The crystallinity of thin films deposited on Si(100) substrates was improved by UV irradiation using a low-pressure mercury lamp. The reaction using the ultrahigh-pressure mercury lamp depended on the substrate type.