bluuebunny/crossref_metadata_2025 huggingface dataset:
Systems biology-defined NF-κB regulons, interacting signal pathways and networks are implicated in the malignant phenotype of head and neck cancer cell lines differing in p53 status
Authors: Yan Bin , Chen Guang , Saigal Kunal , Yang Xinping , Jensen Shane T , Van Waes Carter , Stoeckert Christian J , Chen Zhong
Published: March 2008

Background

Aberrant activation of the nuclear factor kappaB (NF-κB) pathway has been previously implicated as a crucial signal promoting tumorigenesis. However, how NF-κB acts as a key regulatory node to modulate global gene expression, and contributes to the malignant heterogeneity of head and neck cancer, is not well understood.

Results

To address this question, we used a newly developed computational strategy, COGRIM (Clustering Of Gene Regulons using Integrated Modeling), to identify NF-κB regulons (a set of genes under regulation of the same transcription factor) for 1,265 genes differentially expressed by head and neck cancer cell lines differing in p53 status. There were 748 NF-κB targets predicted and individually annotated for RELA, NFκB1 or cREL regulation, and a prevalence of RELA related genes was observed in over-expressed clusters in a tumor subset. Using Ingenuity Pathway Analysis, the NF-κB targets were reverse-engineered into annotated signature networks and pathways, revealing relationships broadly altered in cancer lines (activated proinflammatory and down-regulated Wnt/β-catenin and transforming growth factor-β pathways), or specifically defective in cancer subsets (growth factors, cytokines, integrins, receptors and intermediate kinases). Representatives of predicted NF-κB target genes were experimentally validated through modulation by tumor necrosis factor-α or small interfering RNA for RELA or NFκB1.

Conclusion

NF-κB globally regulates diverse gene programs that are organized in signal networks and pathways differing in cancer subsets with distinct p53 status. The concerted alterations in gene expression patterns reflect cross-talk among NF-κB and other pathways, which may provide a basis for molecular classifications and targeted therapeutics for heterogeneous subsets of head and neck or other cancers.
Phase I Pharmacokinetic and Pharmacodynamic Study of the Oral Mammalian Target of Rapamycin Inhibitor Everolimus in Patients With Advanced Solid Tumors
Authors: O'Donnell Anne , Faivre Sandrine , Burris Howard A. , Rea Daniel , Papadimitrakopoulou Vassiliki , Shand Nicholas , Lane Heidi A. , Hazell Katharine , Zoellner Ulrike , Kovarik John M. , Brock Cathryn , Jones Suzanne , Raymond Eric , Judson Ian
Published: March 2008

Purpose

To identify the optimal regimen and dosage of the oral mammalian target of rapamycin inhibitor everolimus (RAD001).

Methods

We performed a dose-escalation study in advanced cancer patients administering oral everolimus 5 to 30 mg/wk, with pharmacokinetic (PK) and pharmacodynamic (PD) studies. PD data prompted investigation of 50 and 70 mg weekly and daily dosing at 5 and 10 mg.

Results

Ninety-two patients were treated. Dose-limiting toxicity was seen in one patient each at 50 mg/wk (stomatitis and fatigue) and 10 mg/d (hyperglycemia); hence, the maximum-tolerated dose was not reached. S6 kinase 1 activity in peripheral-blood mononuclear cells was inhibited for at least 7 days at doses ≥ 20 mg/wk. Area under the curve increased proportional to dose, but maximum serum concentration increased less than proportionally at doses ≥ 20 mg/wk. Terminal half-life was 30 hours (range, 26 to 38 hours). Partial responses were observed in four patients, and 12 patients remained progression free for ≥ 6 months, including five of 10 patients with renal cell carcinoma.

Conclusion

Everolimus was satisfactorily tolerated at dosages up to 70 mg/wk and 10 mg/d with predictable PK. Antitumor activity and PD in tumors require further clinical investigation. Doses of 20 mg/wk and 5 mg/d are recommended as appropriate starting doses for these studies.
Identifying Optimal Biologic Doses of Everolimus (RAD001) in Patients With Cancer Based on the Modeling of Preclinical and Clinical Pharmacokinetic and Pharmacodynamic Data
Authors: Tanaka Chiaki , O’Reilly Terence , Kovarik John M. , Shand Nicholas , Hazell Katharine , Judson Ian , Raymond Eric , Zumstein-Mecker Sabine , Stephan Christine , Boulay Anne , Hattenberger Marc , Thomas George , Lane Heidi A.
Published: March 2008

Purpose

To use preclinical and clinical pharmacokinetic (PK)/pharmacodynamic (PD) modeling to predict optimal clinical regimens of everolimus, a novel oral mammalian target of rapamycin (mTOR) inhibitor, to carry forward to expanded phase I with tumor biopsy studies in cancer patients.

Patients and Methods

Inhibition of S6 kinase 1 (S6K1), a molecular marker of mTOR signaling, was selected for PD analysis in peripheral blood mononuclear cells (PBMCs) in a phase I clinical trial. PK and PD were measured up to 11 days after the fourth weekly dose. A PK/PD model was used to describe the relationship between everolimus concentrations and S6K1 inhibition in PBMCs of cancer patients and in PBMCs and tumors of everolimus-treated CA20948 pancreatic tumor-bearing rats.

Results

Time- and dose-dependent S6K1 inhibition was demonstrated in human PBMCs. In the rat model, a relationship was shown between S6K1 inhibition in tumors or PBMCs and antitumor effect. This allowed development of a direct-link PK/PD model that predicted PBMC S6K1 inhibition-time profiles in patients. Comparison of rat and human profiles simulated by the model suggested that a weekly 20- to 30-mg dose of everolimus would be associated with an antitumor effect in an everolimus-sensitive tumor and that daily administration would exert a greater effect than weekly administration at higher doses.

Conclusion

A direct-link PK/PD model predicting the time course of S6K1 inhibition during weekly and daily everolimus administration allowed extrapolation from preclinical studies and first clinical results to select optimal doses and regimens of everolimus to explore in future clinical trials.
Review of Field Studies of Aircraft Noise-Induced Sleep Disturbance
Authors: Michaud David S. , Fidell Sanford , Pearsons Karl , Campbell Kenneth C. , Keith Stephen E.
Published: March 2008

Aircraft noise-induced sleep disturbance (AN-ISD) is potentially among the more serious effects of aircraft noise on people. This literature review of recent field studies of AN-ISD finds that reliable generalization of findings to population-level effects is complicated by individual differences among subjects, methodological and analytic differences among studies, and predictive relationships that account for only a small fraction of the variance in the relationship between noise exposure and sleep disturbance. It is nonetheless apparent in the studied circumstances of residential exposure that sleep disturbance effects of nighttime aircraft noise intrusions are not dramatic on a per-event basis, and that linkages between outdoor aircraft noise exposure and sleep disturbance are tenuous. It is also apparent that AN-ISD occurs more often during later than earlier parts of the night; that indoor sound levels are more closely associated with sleep disturbance than outdoor measures; and that spontaneous awakenings, or awakenings attributable to nonaircraft indoor noises, occur more often than awakenings attributed to aircraft noise. Predictions of sleep disturbance due to aircraft noise should not be based on over-simplifications of the findings of the reviewed studies, and these reports should be treated with caution in developing regulatory policy for aircraft noise.
Power and Type I errors for pairwise comparisons of means in the unequal variances case
Authors: Ramsey Philip H. , Ramsey Patricia P.
Published: March 2008

A Monte Carlo simulation was conducted to compare pairwise multiple comparison procedures. The number of means varied from 4 to 8 and the sample sizes varied from 2 to 500. Procedures were evaluated on the basis of Type I errors, any‐pair power and all‐pairs power. Two modifications of the Games and Howell procedure were shown to make it conservative. No procedure was found to be uniformly most powerful. For any pair power the Games and Howell procedure was found to be generally most powerful even when applied at more stringent levels to control Type I errors. For all pairs power the Peritz procedure applied with modified Brown–Forsythe tests was found to be most powerful in most conditions.
„… sed vitae discimus“ Religionsunterricht zwischen Religiosität und christlicher Tradition – didaktische Orientierungen
Authors: Pohl-Patalong Uta
Published: March 2008

Religious education today is shaped by the tension between a vague “general religiousness” and an orientation in the Christian tradition. This tension should not be resolved on only one side, but should be shaped constructively. Therefore, the question of how the Christian tradition can serve life, is raised by the concept of general religiousness, should be considered. The most important task of Christian religious education in this perspective would be for pupils to experience the Christian tradition as serving their lives. This question should also be asked to other religions and forms of religiousness because these too are treated in religious education, which has an interreligious dimension. Christian religious education can thus show its ability for pluralism, without having a lack of position. This orientation has consequences for the training of the teachers.
New Wine and New Wineskins: Laity and a Liberative Future for the Church
Authors: Mannion Gerard
Published: March 2008

The purpose of this essay is to pose questions for practical theology concerning a liberative, community-based ecclesiology, and to pose questions for church leaders regarding the role of laity in shaping the future of the Roman Catholic Church. Identifying some critical issues before the church, the author proceeds to engage with liberative ecclesial visions, drawing particularly on the conceptual revisions advocated by Hermann Pottmeyer, the social and communitarian ecclesiologies of Latin American liberation theology (especially that of Leonardo Boff), and Paul Lakeland's work connecting liberation thinking with Euro-North American contexts. Mannion concludes with a vision for the future of the church, placed within a liberative ecclesiology and a vibrant lay ministry. He also suggests directions for practical theology. His intention throughout is to propose new wine (visions for the people of God) in new wineskins (ecclesial forms, policies, and structures) in which the new wine might mature.
A Study of Ministerial Identity and Theological reflection among Lay Ecclesial Ministers
Authors: O'Brien Maureen R
Published: March 2008

This essay explores ministerial identity and its formation in the context of theological reflection. In particular, it discusses theological premises, the values of narrative inquiry, and the results of a qualitative study of lay ministers participating in a university-based ministry education program. By engaging in a series of interviews, the author also gives a picture of the ambiguous and evolving nature of “lay ecclesial ministry” in the United States Catholic Church. This underscores the need of lay ministers for models of conversation-based theological reflection to aid their self-construction of ministerial identity. After an overview of the study's premises and methods, the essay presents key findings from analysis of the interviews. These findings focus on the construction of ministerial identity; the emergence of ministerial “touchstones”; the dynamics of informal and formal modes of theological reflection; and remaining questions and areas for continued research.
TRIPs, TRIPs-PLUS, Developing Countries and Public Health: The Case of Egypt
Authors: El Farag Mohamed Salem Abou
Published: March 2008

The article critically examines how Egyptian legislators made use of the degree of freedom left in the TRIPs Agreement for WTO Members to incorporate appropriate measures in their national laws aiming at meeting the public health needs and concerns, particularly access to quality health care and affordable pharmaceutical drugs. The article also explores and warns against the recent attempts made by a number of developed countries to impose TRIPs-plus obligations on several developing countries, including Egypt, for their detrimental effects on public health.
Take three cases: A reflection on the mission of applying law to human frailty
Authors: Levy Sharon
Published: March 2008

The birth in 1968 of Louise Brown, the first English test tube baby, was a beacon of hope to the estimated 1 in 7 couples who experience difficulty in conceiving a child. It was obvious that the process of assisted conception required regulation to deal with the legal and ethical ramifications of the developments science had given us and after much consultation and debate, The Human Fertilisation and Embryology Act 1990 was passed.
Post-Merck KGaA v. Integra, A Negative Impact On “Research Tools”?
Authors: Olson Bradley J
Published: March 2008

In the approximately two and a half years since the United States Supreme Court issued its opinion in
The shaping of Gorbachev: On framing in an interpreter-mediated talk-show interview
Authors: Wadensjö Cecilia
Published: March 2008

This paper examines a televised interview that BBC journalist and show host Clive Anderson conducted with the former head of state of the dissolved USSR, Mikhail Gorbachev, assisted by the interpreter Pavel Palazchenko. The paper explores this interview, focusing on its opening and closing, its local organization, and the involvement of the audience. Applying conversation analysis, the paper traces the generic belonging of current talk and looks into a variety of features that shaped the image of Gorbachev as a television personality in British TV. It demonstrates how Gorbachev and Anderson moved between and played with a ‘talk show interview’ and a ‘news interview’ framing of interaction. The analysis demonstrates how the encounter helped portray Gorbachev as a witty and adequate performer, irrespective of the fact that he did not speak English—the language of the broadcast and of the viewers. This was due to what he said, but no less to how he performed, and not least to his way of utilizing the assistance of the highly skilled interpreter, and also, I will argue, to the fact that the interview allowed him to take part in a shared game of entertainment, in a genuinely hybrid form of talk.
Fahrlässige Mittäterschaft in Japan
Authors: Utsumi Tomoko
Published: March 2008

I. Einleitung

Im 20. Jahrhundert hat die Entwicklung der Technik zur Zunahme der Produktivität und zur Erhöhung des Lebensstandards geführt. Unsere Gesellschaft ist jedoch andererseits einer erhöhten Gefahr von Rechtsgutverletzungen durch den Missbrauch von Technologien ausgesetzt. Es ist den Einzelnen unmöglich, sämtliche technischen Gefahren allein zu überwachen und Unfälle zu vermeiden. Daher ist es eine Aufgabe der Gesellschaft, die neuen Technologien für das Alltagsleben nützlich zu machen und ihre Gefahren angemessen zu kontrollieren. Es steht allerdings zu erwarten, dass Fälle zunehmen werden, in denen die Nachlässigkeit mehrerer Personen zusammenwirkt. Die wissenschaftliche Beschäftigung mit dieser Konstellation wird deshalb immer wichtiger.
Long-term Safety and Efficacy Results of Once-Daily Emtricitabine-Based Highly Active Antiretroviral Therapy Regimens in Human Immunodeficiency Virus-Infected Pediatric Subjects
Authors: Saez-Llorens Xavier , Violari Avy , Ndiweni Dalubuhle , Yogev Ram , Cashat Miguel , Wiznia Andrew , Chittick Greg , Harris Jeanette , Hinkle John , Blum M. Robert , Adda Nathalie , Rousseau Franck ,   for the FTC-203 Study Team
Published: March 2008

OBJECTIVES. The purpose of this work was to obtain long-term safety and efficacy data for antiretroviral regimens containing emtricitabine in HIV-infected pediatric subjects and confirm that a pediatric dose of 6 mg/kg once daily would provide steady-state emtricitabine concentrations comparable to those observed in adults given 200 mg of emtricitabine once daily.

PATIENTS AND METHODS. HIV-infected subjects between 3 months and 16 years of age were enrolled, including 71 antiretroviral-naïve subjects and 45 antiretroviral-experienced subjects. Naive subjects received emtricitabine plus stavudine plus lopinavir or ritonavir. Experienced subjects replaced the lamivudine in their existing regimens with emtricitabine. Tolerance, safety, disease progression, and virologic and immunologic responses were evaluated.

RESULTS. The Kaplan-Meier probability of persistent virologic response in the intent-to-treat population through week 164 at ≤400 copies per mL and ≤50 copies per mL was 74% and 62%, respectively. Three subjects (3%) discontinued the study for adverse events, 8 (7%) for virologic failure, and 1 died through a median follow-up of 164 weeks. The annualized incidence rate of grade 3 to 4 adverse events and grade 3 to 4 laboratory abnormalities was 6% and 3%, respectively. The annualized incidence rate of serious adverse events was 9%, with 1% attributed as related to emtricitabine. Genotypic analysis showed the emergence of the M184V mutation in 4 of the 15 subjects who experienced virologic failure through week 164. Pharmacokinetic evaluation demonstrated plasma drug exposures in these children comparable to adults receiving the approved dose of 200 mg once daily.

CONCLUSIONS. These results demonstrate the safety and efficacy of emtricitabine in pediatric patients. They also support that the safety and efficacy profile of emtricitabine in children is similar to that demonstrated in adults.
Randomized, Double-Blind, Placebo-Controlled Trial of Probiotics for Primary Prevention: No Clinical Effects ofLactobacillusGG Supplementation
Authors: Kopp Matthias Volkmar , Hennemuth Isabell , Heinzmann Andrea , Urbanek Radvan
Published: March 2008

BACKGROUND. The value of probiotics for primary prevention is controversial. Published trials vary considerably in study design and the applied probiotics, thereby limiting comparability of the results.

OBJECTIVE. The purpose of this trial was to study the preventive effect of the probiotic Lactobacillus GG on the development of atopic dermatitis.

METHODS. In a double-blind, placebo-controlled prospective trial, 105 pregnant women from families with ≥1 member (mother, father, or child) with an atopic disease were randomly assigned to receive either the probiotic Lactobacillus GG (American Type Culture Collection 53103; 5 × 109 colony-forming units of Lactobacillus GG twice daily) or placebo. Ninety-four families (89.5%) completed the trial. The supplementation period started 4 to 6 weeks before expected delivery, followed by a postnatal period of 6 months. The primary end point was the occurrence of atopic dermatitis at the age of 2 years. Secondary outcomes were severity of atopic dermatitis, recurrent episodes of wheezing bronchitis, and allergic sensitization at the age of 2 years.

RESULTS. Atopic dermatitis was diagnosed in 14 (28%) of 50 in the Lactobacillus GG group and in 12 (27.3%) of 44 in the placebo group. The risk of atopic dermatitis in children on probiotics relative to placebo was 0.96 (confidence interval 0.38–2.33). Severity of atopic dermatitis was comparable between the 2 groups. Notably, children with recurrent (≥5) episodes of wheezing bronchitis were more frequent in the Lactobacillus GG group (26%; n = 13), as compared with the placebo group (9.1%; n = 4). No difference was observed between both groups in total immunoglobulin E concentrations or numbers of specific sensitization to inhalant allergens.

CONCLUSIONS. Supplementation with Lactobacillus GG during pregnancy and early infancy neither reduced the incidence of atopic dermatitis nor altered the severity of atopic dermatitis in affected children but was associated with an increased rate of recurrent episodes of wheezing bronchitis. Therefore, Lactobacillus GG cannot be generally recommended for primary prevention.
Whisker/matrix interface and microstructure of MgO-whisker reinforced (Bi, Pb)2Sr2Ca2Cu3Ox high-temperature superconducting composite
Authors: Yuan Y. S. , Wong M. S. , Wang S. S.
Published: March 2008

In this paper, a comprehensive study of the microstructure and the whisker/matrix interface of a (MgO)w/BPSCCOhigh-temperature superconducting composite is reported. The bulk MgO-whisker reinforced HTS BPSCCO (2223) composite was fabricated using a recently developed solid-state processing method. The (MgO)w/BPSCCO composite has been demonstrated to possess excellent combined superconducting and mechanical properties. The favorable microstructure of the HTS BPSCCO (2223) matrix and the (MgO)w/BPSCCO interfacial properties are recognized to be the critical material parameters governing electric and mechanical performance of the HTS composite. Effects of detailed microstructure variables on superconducting properties of the composite are addressed, including the aspect ratio and the orientation of MgO whiskers, structure, and texturing of the BPSCCO matrix phase, and the (MgO)w/BPSCCO interfacial microchemistry. The results obtained reveal unique characteristics of the reinforcing MgO whiskers dispersion, distribution, and orientation in the HTS composites. The evolution of the microstructure and texture of thematrix BPSCCO grains has also been studied in the process of repeated hot-pressing and annealing heat treatment. The thermodynamic compatibility and microchemistry in the MgO whisker and BPSCCO interfaceare also examined.
A two-powder process for Bi-2223 precursors
Authors: Holesinger T. G. , Salazar K. V. , Phillips D. S. , Sargent B. L. , Bremser J. K. , Bingert J. F. , Willis J. O. , Peterson D. E.
Published: March 2008

A two-powder process is described for the production of uniform, fine-grained Bi2Sr2Ca2Cu3Oy (Bi-2223) powders. One powder is the Bi2.1−xPbxSr1.9−yCayOz (2:2 Cu-free) phase. The other is a multi-phase powder of approximate overall composition SrCaCu3Oy. The 2:2 Cu-free is one of the first Bi-containing phases to form from a nominal Bi-2223 mixture of oxides and carbonates. This precursor route was chosen for investigation because (1) the powders have very similar particle morphologies and (2) the mixing volumes are closely matched. Both of these characteristics facilitate the milling and blending process. This precursor mix was found to be stable in that explosive grain growth of undesirable phases was not observed during sintering. Critical current densities up to 26,900 A/cm2 in self field at 75 K were obtained in tapes.
Lattice distortion of thick epitaxial layers
Authors: Bickmann K. , Hauck J.
Published: March 2008

Precise x-ray diffraction measurements between room temperature and ∼400 °C (Bond method) exhibit some details in the variations of strain in ∼ 1 μm thick epitaxial layers of GaAs, InP, CdTe, EuS, or SrS on Si or GaAs substrates. The lattice parameters of the cubic layers, which are deposited at high temperatures, deviate from the lattice parameters, a0, of small unconstrained single crystals by Δa/a0 = ∈0 ≲ 10−3. The layers adhere to the substrates below Tc and adopt different strains, ∈‖ and ∈⊥, parallel and perpendicular to the substrate. Frequently the Tc and ∈0 values vary on annealing at 160–400 °C. The ratio E = —(∈⊥ — ∈0)/(∈‖ — ∈0) remains constant for each sample. The change of the relative volume ΔV/V0 = ∈‖ (2—E) +∈0 (1 + E) at the variation of ∈0 can give rise to corrugations, blisters, or microcracks in the epitaxial layers. Stable epitaxial layers with constant ∈0 and Tc values can be obtained by deposition on buffer layers or stepped substrates.
Latest developments for microstructural and chemical characterization of diffusion bonding in superplastic 8090 Al–Li alloys
Authors: Ureña A. , de Salazar J. M. Gómez , Martín J. J. , Quiñones J.
Published: March 2008

This paper describes a new application of two complementary surface characterization techniques to study solid-state bonding in an Al–Li alloy. Through the two mentioned techniques, Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS), important findings about what takes place in the bond interface have been determined. These findings enclose both the formation of discontinuous mixed oxides and the evolution of Li through the bond line and into theadjacent diffusion affected zones. Homogenization of Li and Cu alloyelements has been detected even in those cases where a metallic interlayer was used to favor the union.
Relationships among thermomechanical treatments, microstructure, and tensile properties of a near beta-titanium alloy: β-CEZ: Part I. Relationships between thermomechanical treatments and microstructure
Authors: Mora L. , Quesne C. , Haut C. , Servant C. , Penelle R.
Published: March 2008

The high strength medium temperature and β metastable titanium alloy, β-CEZ, is designed for use in the compressor of a jet engine. The purpose of this research was to investigate how the thermomechanical treatments (forging or solutioning conditions and quenching) influence the microstructure. A series of various heat-treating steps were conducted in order to quantify the relationship between thermomechanical parameters and microstructural factors. The detailed characterization of microstructure was based on SEM observations of primary alpha platelets with the aid of an Image Analysis system. A pronounced influence of thermomechanical treatments on microstructure was found. Several parameters characterizing the microstructure of alpha platelets such as the area fraction, length, width, perimeter, surface, density, and aspect ratio, have been found to depend on the solutioning conditions. Furthermore, with the exception of the area fraction, these different microstructural parameters were found to be also governed by the forging conditions.
Amorphous ceramics as the particulate phase in electrorheological materials systems
Authors: Gamota Daniel R. , Schubring Adam W. , Mueller Brian L. , Filisko Frank E.
Published: March 2008

Several electrorheological (ER) materials systems composed of amorphous ceramic powders dispersed in light paraffin oil were developed to determine if relationships among ER activities, dielectric properties, compositions, porosities, and oxide species could be identified. The results of the studies suggested that trends among ER activity, dielectric phenomena, and alkali metal species existed. The aluminosilicate powders developed with various alkali metals showed that the ER activity increased as the activation energy decreased. The sodium aluminosilicate appeared to have the greatest ER activity and the lowest activation energy, while the cesium aluminosilicate displayed the weakest ER response, but had the highest activation energy. The thermodielectric responses of the different oxide materials systems developed with sodium showed that the mechanisms contributing to the dielectric dispersions had similar activation energies; however, the magnitudes of the recorded ER activities varied, and thus a direct correlation was not apparent. In addition, studies conducted with ER materials composed of sodium aluminosilicate powders of varying porosities showed that ER activities increased with increasing porosity. Furthermore, the analysis of the results of the thermodielectric and rheological studies of the different amorphous materials ER systems suggested that these materials may have an optimal stimulus frequency/temperature for ER activity.
Electrochemical synthesis of barium titanate thin films
Authors: Bacsa R. R. , Rutsch G. , Dougherty J. P.
Published: March 2008

Polycrystalline films of barium titanate (BaTiO3) have been synthesized on titanium (Ti) substrates by the galvanostatic anodization of Ti in a solution of 0.4 M Ba(OH)2. Crystalline films are formed at temperatures under 100 °C within 10 min at a current density of 25 mA/cm2 at atmospheric pressure. Crystallinity of the films is found to increase with both current density and time of reaction. At 90 °C, a film of 1 μm thickness is formed after 10 min; grain sizes up to 0.5 μm are obtained. Microstructure of the films is found to be critically dependent on the pretreatment of the titanium anode. Capacitance measurements on the film yield a dielectric constant of 200 with a minimum tan delta of 0.09 at 10 kHz. On the basis of the voltage-time curves, it is interpreted that an amorphous intermediate is formed which crystallizes to form perovskite BaTiO3.
Chromium implantation in silica glass
Authors: Cattaruzza E. , Bertoncello R. , Trivillin F. , Mazzoldi P. , Battaglin G. , Mirenghi L. , Rotolo P.
Published: March 2008

Silica glass was implanted with chromium at the energy of 35 and 160 keV and at fluences varying from 1 × 1016 to 11 × 1016 ions cm−2. In a set of chromium-implanted samples significant amounts of carbon were detected. Samples were characterized by x-ray photoelectron spectroscopy, x-ray-excited Auger electron spectroscopy, secondary ion mass spectrometry, and Rutherford backscattering spectrometry. Chromium silicide and chromium oxide compounds were observed; the presence of carbon in the implanted layers induces the further formation of chromium carbide species. Thermodynamic considerations applied to the investigated systems supply indications in agreement with the experimental evidences.
From small angle x-ray scattering to reflectivity: Instrumentation and sample study
Authors: Hua D. W. , Beaucage G. , Kent M. S.
Published: March 2008

In this study, we described the first results from an x-ray reflectometer which has been modified from an existing Kratky small angle x-ray scattering (SAXS) camera at the UNM/Sandia scattering center. Typically, seven orders of magnitude of reflectivity can be obtained over a range of 0.02 to 0.5 Å−1 in q. This allows the resolution of surface features of 10 to 1000 Å. The conversion to reflectometer is reversible and can be achieved in a short time, allowing for dual use of an existing Kratky camera.
Phase identification in a U–Zr/Ni–Cr diffusion couple using synchrotron radiation
Authors: Petri M. C. , Leibowitz L. , Mueller M. H. , Richardson J. W. , Keiser D. D.
Published: March 2008

The diffusion zone between a U–23 at. % Zr alloy and a Ni–16.4 at. % Cr alloy exhibited nine distinct phase layers, many of which were mixtures of two phases. Four single-phase regions were less than 10 μm wide. To identify these phases by diffractometry, a synchrotron x-ray beam was collimated by a 50 μm by 1 mm slit. This beam was translated across the sample to obtain diffraction patterns throughout the diffusion zone. In this way, only a few phases were simultaneously within the beam, easing identification of the phases. Strains in the lattice due to solid solution were also observed. These microdiffraction techniques are applicable to a wide range of material systems.
Rapid consolidation processing of silicon nitride powders
Authors: Schneider J. A. , Risbud S. H. , Mukherjee A. K.
Published: March 2008

Using a Plasma Assisted Sintering (PAS) process, submicron size, silicon nitride powders were consolidated to >99% of the theoretical density (TD) at 1750 °C in less than 5 min with retention of the a phase and the submicron grain size. The silicon nitride powders were sintered with 5 wt.% Y2O3 and 5 wt.% Y2O3 + 5 wt. % MgAl2O4 additives. The PAS processing method for the silicon nitride additive mixtures is attractive for retention of fine-grained microstructures favorable for superplastic deformation. Post superplastic forming heat treatments to transform the α−Si3N4 to lath-like, creep-resistant β−Si3N4 is another feature of the present processing method.
Preparation and characterization of GeS2
Authors: Stanić Vesna , Pierre Alain C. , Etsell Thomas H. , Mikula Randy J.
Published: March 2008

Synthesis of GeS2 via a sol-gel process using germanium ethoxide and hydrogen sulfide in toluene resulted in a gel aggregate with an apparent Ge/S ratio 1:1.8. Special precautions were necessary to protect the reaction mixture from water contamination which produced GeO2. Results indicated that the main source of water was the hydrogen sulfide gas. Heat treatment of the produced GeSx gel yielded a product with Ge/S ratio 1:2.3. The sol-gel prepared materials and their heat-treated products were characterized by various methods.
Eutectoid temperature of carbon steel during laser surface hardening
Authors: Chen Chin-Cheng , Tao Chun-Ju , Shyu Lih-Tyan
Published: March 2008

A new method was developed to determine the eutectoid temperature, Ac1, of carbon steel during laser surface hardening. In the method a three-dimensional heat flow model with temperature-dependent physical properties was set up and solved for the temperature distribution employing a finite element method (FEM). Workpieces were heat-treated to produce a melted and hardened zone by a single pass of a continuous-wave TEM00 CO2 laser beam. The depth profile of the melted zone was used as a calibrator to solve the uncertainty imposed by the unknown surface absorptivity. Obtained was an Ac1 of, on average, 770 °C, a superheat of 47 °C compared to the equilibrium Ac1 of 723 °C. Furthermore, the numerical model was also employed to predict the hardened depth, and the results show that, for a depth of more than 100 μm, the eutectoid temperature 770 °C leads to a depth about 10% smaller than that predicted at 723 °C. The use of the temperature-dependent physical properties is critical; an error up to 80% could result if constant physical properties are used.
Microstructural changes in welded Zn–Al alloy
Authors: Zhu Yao Hua
Published: March 2008

Extruded eutectoid Zn–Al alloy was welded by a melt of the same eutectoid alloy. Two different microstructures were observed in the joint part and in the bulk of the welded alloy. Typical dendritic structure of as-cast Zn–Al alloy was observed in the joint part of the welded alloy. The bulk of the welded Zn–Al alloy appeared as fine grain structure. Two different metastable phases, η′T decomposed from η′s of the chilled as-cast state and η′E of the extruded state, were found to be unstable during the early stages of aging. A four-phase transformation occurred after the decompositions of these two metastable phases of η′T. Microstructures of both the joint part and bulk of the welded alloy were investigated simultaneously during the aging processes.
A study of solid-state amorphization in Zr–30 at. % Al by mechanical attrition
Authors: Biswas A. , Dey G. K. , Haq A. J. , Bose D. K. , Banerjee S.
Published: March 2008

Elemental powders of zirconium and aluminum in the atomic ratio of 70:30 were mechanically alloyed in an attritor under argon atmosphere using zirconia balls as milling media. Samples have been taken out for characterization after different durations of milling. The process of alloying and resultant amorphization had been studied using x-ray diffraction (XRD) and transmission electron microscopy (TEM). Scanning electron microscopy (SEM) was carried out to study the morphological changes occurring during repeated cold welding and breaking of the particles. Samples for TEM study were prepared by dispersing the mechanically attrited particles in the nickel foil by electrochemical codeposition. TEM study of the initial stages of milling revealed that localized structural changes precede the bulk amorphization process during mechanical alloying (MA). The sequence of phase evolution has been identified as (i) the formation of nanocrystalline supersaturated solid solution of aluminum in α-zirconium, (ii) amorphization of localized regions at powder interfaces, (iii) ordering of aluminum-rich regions in the metastable Zr3Al (DO19) phase, and, finally, (iv) bulk amorphization of the powders.
Sol-gel synthesis of microcrystalline rare earth orthophosphates
Authors: Guo Yan , Woznicki Patricia , Barkatt Aaron , Saad Elie E. , Talmy Inna G.
Published: March 2008

Studies of the reactions between rare earth salts and phosphoric acid in aqueous or ethanolic media have shown that in both cases stable gels can be formed. Upon drying, gels prepared in aqueous environments yield macrocrystalline REPO4 products similar to those produced by conventional precipitation and drying. Gels prepared in ethanol, on the other hand, undergo dehydration to form dense microcrystalline products. This observation is based on optical and scanning electron microscopy, as well as on x-ray diffraction studies and infrared spectroscopy. These techniques, as well as differential thermal analysis, indicate that crystal growth of these products takes place around 600−700 °C. The composition of the dehydrated gels produced in both the aqueous and ethanolic systems corresponds to an orthophosphate structure. Other characteristics of the microcrystalline REPO4 products include high resistance to attack by water, absence of coloration upon exposure to gamma rays, and a high index of refraction.
Elevated temperature deformation of fine-grained La0.9Sr0.1MnO3
Authors: Wolfenstine J. , Armstrong T. R. , Weber W. J. , Boling-Risser M. A. , Goretta K. C. , Routbort J. L.
Published: March 2008

Compressive creep behavior of fine-grained (5 μm) La0.9Sr0.1MnO3with a relative theoretical density between 85 and 90% was investigated over the temperature range 1150–1300 °C in air. The fine grain size, brief creep transients, stress exponent close to unity, and absence of deformation-induced dislocations, suggested that the deformation was controlled by a diffusional creep mechanism. The activation energy for creep of La0.9Sr0.1MnO3was 490 kJ/mole. A comparison of the activation energy for creep of La0.9Sr0.1MnO3with existing diffusion and creep data for perovskite oxides suggested that the diffusional creep of La0.9Sr0.1MnO3was controlled by lattice diffusion of the cations, either lanthanum or manganese.
Electrically conductive CuS–poly(acrylic acid) composite coatings
Authors: Hu H. , Campos J. , Nair P. K.
Published: March 2008

Copper sulfide (CuS) powder precipitated from a chemical bath containing Cu(II) chloride and thiourea and annealed in air at 150 °C for 1 h was dispersed in a poly(acrylic acid) aqueous solution (with additional water or propylene glycol as a dispersive agent) and cast on glass slides. Upon evaporation of the solvent, coatings of ∼50 μm in thickness of a CuS-poly(acrylic acid) composite are formed. Measurement of sheet resistance (R□) indicates a percolation threshold of electrical conduction at a weight fraction [wf is wt. % of CuS to poly(acrylic acid) + CuS] of about 40%; the composite undergoes a transition from insulator (R□ ∼ 1013 Ω) to conductive state (R□ ∼ 102 Ω). The morphology and thermal stability of the composite depend on the choice of the dispersive agent for the CuS powder; smoother and thermally stable (up to a temperature of 250 °C) coatings are obtained when propylene glycol is used. The results on x-ray diffraction, thermogravimetric analysis, and Fourier transform infrared spectroscopy studies are given to indicate the structure and bonding mechanisms and their dependence on temperature and dispersive agents.
Influence of the composition of gas mixture on the stoichiometry of sputter-deposited compound films: The case of zirconium nitrides
Authors: Wautelet M. , Dauchot J. P. , Debal F. , Edart S. , Hecq M.
Published: March 2008

By means of dc-reactive sputtering, it is possible to vary the stoichiometry of deposited zirconium nitrides, by varying the molar fraction of N2 in an Ar–N2 gas mixture. In order to understand the origin of this effect, a theoretical model of reactive sputtering is devised. It is based on the study of reaction kinetics taking place at the surfaces of the cathode and the chamber walls. In fitting the model with experimental data, it turns out that one has to introduce the roles of Ar, N2, and N species. For reactive sputtering of ZrNz films, a good fit is obtained when it is assumed that the molar fraction of N is constant when the molar fraction of N2 increases up to about 75% (under our experimental conditions). Above this concentration of N2, the concentration of N has to increase. By the analysis of the theoretical model, general scaling laws between experimental parameters (current, pressure, and areas of the cathode and the chamber walls) are easily obtained.
A simple method for the manufacture of mesoscopic metal wires
Authors: Noel S. , Batalla E. , Rochon P.
Published: March 2008

A process for the manufacture of very thin parallel wires has been developed. A series of parallel silver wires have been written for the study of one-dimensional electron transport. The wires are approximately 200 nm wide and 8 mm long. The method used can produce longer and thinner wires.
Characterization of surface microroughness of silicon wafers by a multipass Fabry–Perot Rayleigh–Brillouin scattering spectrometer
Authors: Taijing Lu , Ng S. C. , Furukawa J. , Furuya H.
Published: March 2008

Surface microroughness of various Si(100) wafers was detected and characterized by a 180° backscattering Rayleigh–Brillouin scattering spectrometer (RBSS), and measured by an atomic force microscopy (AFM). The intensity of the scattered light from the wafers is found to increase with increasing surface microroughness which was measured by AFM. By scanning across the wafer, the inhomogeneous distribution of surface microroughness is detected and characterized. The system can be easily developed into a mapping technique. The results of the surface microroughness detected by AFM and RBSS suggest that they are complementary for the characterization of the surface microroughness from a microarea to a whole wafer.
RF aerosol plasma fabrication of indium tin oxide and tin oxide thin films
Authors: Lee D. H. , Vuong K. D. , Williams J. A. A. , Fagan J. , Condrate R. A. , Wang X. W.
Published: March 2008

Transparent, conductive indium-tin oxide (ITO) and tin oxide thin films were deposited on soda-lime-silicate (SLS) float glass and silica glass substrates by an RF aerosol plasma technique in an atmospheric environment. The ITO films were deposited from solutions with various In: Sn ratios. The dependence of the film properties on the substrate temperature, deposition time, and tin concentration has been studied. The films were characterized by several techniques including XRD, EDS, electrical resistivity, SEM, optical (IR-UV-Vis transmission), Mössbauer, and infrared spectroscopy. The results showed that film phase, morphology, thickness, crystallite size, and conductivity depend on the solution composition and deposition parameters. XRD revealed that In2O3 was present in the film when a In: Sn ratio of 5: 5 or higher was used; otherwise only SnO2 shown. SEM analysis showed that dense and uniform films were formed with particle sizes ranging from approximately 50 nm to 150 nm. The resistivity of the ITO films ranged from 0.12 to 5.0 ohm-cm at room temperature. Optical transmission of the ITO-coated glasses was not different from the uncoated samples. Infrared results indicated that the structure of the near surface of the glasses was significantly modified with a higher indium concentration. The advantages of the atmospheric, RF aerosol plasma deposition process over other techniques are discussed.
Microstructural characterization of ordered nickel silicide structures grown on (111) nickel silicide films
Authors: Ho Herbert L. , Bauer Charles L. , Mahajan Subhash , Laughlin David E. , Milnes Arthur G.
Published: March 2008

The formation processes of epitaxial nickel silicides, resulting from the interaction of nickel silicide films (10 nm–100 nm) on (111) silicon (Si) substrates after furnace annealing, have been studied using transmission electron microscopy (TEM) and x-ray diffraction (XRD) techniques. The formation of type-A epitaxial grains (i.e., grown with the same orientation of the underlying Si substrate) and type-B epitaxial grains (i.e., rotated by 180± around the surface normal) in “thick” epitaxial films (i.e., greater than 35 nm) is proposed to be linked to the formation of a fluorite-based CuPt (L11)-like NiSi phase. This phase is found to be a metastable phase and is believed to be a transitional phase toward the formation of the equilibrium NiSi2 phase in both type-A and type-B orientations. In addition, we have found that a fluorite-based CuPt-like NiSi may even coexist with a fluorite-based CuAu I-like structure. The interrelationship between these two structures is discussed in the context of a displacive transformation process in fcc structures as originally proposed by Hansson and Barnes [Acta Metall. 12, 315 (1964)] and Pashley et al. [Philos. Mag. 19, 83 (1969)].
X-ray diffractometry investigation for ion-exchange properties on alpha-type manganese dioxides
Authors: Tanaka Yasuo
Published: March 2008

Two materials of α-type manganese dioxide were synthesized and examined. They were prepared by the pyrolysis of mixtures of MnCO3 and (CH3)3COK. An ill-ordered material was obtained when prepared at large (CH3)3COK content. Both samples behave as acids, but their apparent capacities are obviously different: about 0.9 meq/g for a well-ordered sample and about 2.6 meq/g for an ill-ordered sample. Ion-exchange properties were examined on Kielland's plot. Zero intersections of the two samples are almost the same but slopes are different (about −50 for a well-ordered sample and about −10 for an ill-ordered sample). The difference in slope is likely caused by the flexibility. An evidence of the flexibility can be seen by x-ray diffractometry.
Preparation of molecular alloys by the ball-milling technique
Authors: Font J. , Muntasell J. , Cesari E. , Pons J.
Published: March 2008

Ball milling is a technique used extensively in metallic powders to obtain adequated properties for their applications. In this study we show that this technique is also useful for preparing organic molecular alloys. Pentaglycerin/Pentaerythritol alloys have been obtained mechanically at room temperature. Calorimetric and crystallographic characterizations establish that the mechanically obtained alloys have the same solid crystalline structure and transform to the plastic phase as the conventionally prepared alloys from the melt of the pure compounds.
Oxygen partial pressure dependence of the yttrium solubility in Y–Ba–Cu–O solution
Authors: Nakamura Masaru , Krauns Christian , Shiohara Yuh
Published: March 2008

The ytrrium solubility in Ba–Cu–O solvent with a Ba to Cu ratio of 3 to 5 was investigated under different oxygen partial pressure [P(O2) = 2, 21, 100%]. A small amount of the solution was taken out by dipping thermally equilibrated MgO single crystals, and compositions of these specimens were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). The measurements were performed for the samples prepared in the temperature range from approximately 950 °C up to 1100 °C. The peritectic temperature of YBa2Cu3O72x (Y123) decreased with decreasing oxygen partial pressure. On the other hand, the Y123 liquidus lines do not show remarkable oxygen partial pressure dependency. Accordingly, the yttrium solubility at the peritectic temperature of Y123 under P(O2) = 100% was larger than those for the other conditions [P(O2) = 2% and 21%]. Assuming a regular solution, expressions for the solubility and the enthalpy of dissolution of Y123 and Y2BaCuO5 (Y211) were derived from classical thermodynamic calculations and found to be 289 kJ/mol at P(O2) = 0.02, 239 kJ/mol at P(O2) = 0.21 atm, 206 kJ/mol at P(O2) = 1 atm for Y123, and 105 kJ/mol at P(O2) = 0.02 atm, 88.0 kJ/mol at P(O2) = 0.21 atm, and 88.4 kJ/mol at P(O2) = 1 atm for Y211. Furthermore, the Jackson α factor of Y123 was estimated to be about 20, confirming a faceted growth nature of this crystal.