bluuebunny/crossref_metadata_2025 huggingface dataset:
Interrelationships Between Inflammation, C‐Reactive Protein, and Insulin Resistance
Authors: Ndumele Chiadi E. , Pradhan Aruna D. , Ridker Paul M
Published: February 2007

The recognition that inflammation plays a fundamental role in atherothrombosis has led to the measurement of circulating inflammatory biomarkers such as high‐sensitivity C‐reactive protein (hs‐CRP) as a means of improving cardiovascular disease detection and prevention. Clinically, levels of hs‐CRP >3 mg/L indicate elevated risk for myocardial infarction and stroke, even among apparently healthy individuals with low‐to‐normal lipid levels. Emerging laboratory and epidemiologic data now link inflammation and hs‐CRP to insulin resistance in that hs‐CRP levels have been associated with impaired insulin sensitivity and the development of dysglycemic conditions, including the cardiometabolic syndrome and incident type 2 diabetes. hs‐CRP has also been associated with each of the individual components of the cardiometabolic syndrome. Furthermore, in large prospective studies, hs‐CRP adds prognostic information about cardiovascular risk beyond that provided by the cardiometabolic syndrome. These findings have led to discussion about the addition of hs‐CRP measurement to the current definition of the cardiometabolic syndrome to improve detection of risk for both diabetes and cardiovascular events in patients. Multiple clinical studies are now underway that are evaluating whether agents traditionally used to improve glycemic control may also significantly reduce hs‐CRP.
Obesity and Insulin Resistance As Risk Factors for Chronic Kidney Disease
Authors: Whaley‐Connell Adam , Pavey Brian S. , Afroze Aneesa , Bakris George L.
Published: February 2007

The cardiometabolic syndrome is a state of metabolic and vascular dysregulation. The cardiometabolic syndrome is clinically composed of a cluster of metabolic abnormalities including insulin resistancelhyperinsulinemia, central/visceral obesity, dyslipidemia, hypertension, microalbuminuria, fibrinolytic and inflammatory abnormalities, endothelial dysfunction, oxidative stress, and hypercoagulability, which collectively lead to an increased risk of cardiovascular and renal outcomes. The development of microalbuminuria is now accepted as a marker of systemic endothelial dysfunction and, if it progresses to macroalbuminuria (i.e., >200 mgld albuminuria), then kidney disease is evident. Collectively, visceral obesity, insulin resistancelhyperinsulinemia, and other components of the cardiometabolic syndrome lead to an increased risk of microalbuminuria and progressive loss of renal function. Hence, aggressive management of risk factors for the metabolic syndrome, nonpharmacologic and pharmacologic, is essential to prevent or delay the progressive loss of renal function and chronic kidney disease.
Fat Cell‐Derived Modulators of Vascular Cell Pathophysiology: The List Keeps Growing
Authors: Marcus Yonit , Stern Naftali
Published: February 2007

Independent of the association of obesity with dyslipidemia, hypertension, and increased propensity for diabetes, fatness per se is increasingly recognized as a cardiovascular offender. That adipose tissue releases a wide range of adipokines, growth factors, enzymes, and enzyme substrates linked to vascular injury provides a plausible explanation for the role of fat in vascular disease: tumor necrosis factor‐α, leptin, resistin, interleukin‐1, ‐6, ‐8, and ‐18, serum amyloid A, monocyte chemoat‐tractant protein I, macrophage inhibitory factor, aortic carboxypeptidase, hepa‐rin‐binding epidermal growth factor‐like growth factor, vascular endothelial growth factor, transforming growth factor β, angiotensinogen, cathepsin S, estradiol, cortisol, mineralocorticoid releasing factor, and calcitonin peptides are probable fat‐derived prothrombotic, proinflammatory, and proatherosclerotic agents acting in a paracrine and/or endocrine manner. Other adipocyte products such as adiponectin, transforming growth factor β, and interleukin‐10 exert some antiatherogenic effects. The following is a short overview of how adipose tissue products affect the vasculature.
Effect of Body Mass Index on Insulin Resistance and Lipids in Prepubertal and Postpubertal Children: SCHOOL Observations
Authors: Murdock David K. , Olson Karen J. , Juza Ryan M. , Hendricks Bryan L.
Published: February 2007

As part of the School Children Have Early Onset of Leading Risk Factors for Cardiovascular Disease and Diabetes Mellitus (SCHOOL) project, this study examines the effect of elevated body mass index on metabolic parameters and its relationship to insulin resistance in prepubertal and postpubertal students from the Wausau School District in central Wisconsin. Two hundred forty‐seven nondiabetic students were randomly selected (125 prepubertal [2nd graders] and 122 postpubertal [11th graders]). Waist/hip ratio and body mass index corrected for age and sex were calculated. Fasting insulin, glucose, and nuclear magnetic resonance lipid profiles were measured. Relative insulin resistance was defined as quantitative insulin sensitivity check index >1 SD below the mean of normal‐weight children. Twentyeight percent of 2nd graders and 33% of 11th graders were overweight. Relative insulin resistance was present in 47% of overweight 2nd graders and 51% of overweight 11th graders and was associated with higher triglycerides, lower high‐density lipoprotein, smaller low‐density lipoprotein particles and, in 11th graders, higher waist/hip ratio. Relative insulin resistance prevalence is high among overweight children and adolescents. Biomarkers of increased risk of adverse cardiovascular outcomes are already present in overweight school children.
Factors Influencing Success Rate of Leukocyte Immunization and Anti‐paternal Antibodies in Spontaneous Recurrent Miscarriage
Authors: Chaichian Shahla , Shoaee Shervan , Saremi Abutaleb , Pedar Setareh , Firouzi Farzad
Published: February 2007

Problem

Paternal leukocyte immunotherapy has been used as treatment for spontaneous recurrent miscarriage, however, controversies have raged against the factors influencing its success.

Methods

Five hundred and forty‐nine women with three or more unexplained pregnancy losses were offered immunization. Two weeks after the second immunization, serum was tested for anti‐paternal cytotoxic antibody (APCA) by cross matching and if revealed positive she was advised pregnancy. Meanwhile, decision trees have been developed by Waikato Environment for Knowledge Analysis package to predict factors influencing APCA production and pregnancy.

Results

Of 549 subjects, 93 (16.9%) revealed to have positive APCA, among whom 49(52.7%) had clinically successful pregnancy (≥28 weeks). Patient's age, consanguinity between couples and previous history of surgery, and infectious, endocrine, immunologic, uterine and cervix disorders were inversely associated with APCA production and clinically successful pregnancy, whilst, number of children was a potent positive predictor.

Conclusion

Leukocyte immunization could be borne in mind as a therapeutic approach in selected subjects. Younger females with negative past medical history who are not frequent aborters are more likely to take benefit from this therapeutic approach if they do not have any familial relationship with their spouse.
Tumor Necrosis Factor‐alpha in Gestation and Puerperium of Women with Gestational Hypertension and Pre‐eclampsia
Authors: Peraçoli José Carlos , Rudge Marilza Vieira Cunha , Peraçoli Maria Terezinha Serrão
Published: February 2007

Problem

High plasma levels of tumor necrosis factor‐alpha (TNF‐α) in pregnant women have been associated with the pathogenesis of pre‐eclampsia (PE). This study evaluated TNF‐α plasma levels and monocyte production in gestational hypertension (GH) and PE during gestation and at puerperium.

Method of study

This study included 128 women, of whom 20 were non‐pregnant (NP) normotensive (NT), and 108 were pregnant: 36 NT, 27 with GH, and 45 with PE. Peripheral blood plasma was used for TNF‐α and uric acid determination. TNF‐α was determined in plasma and lipopolysaccharide (LPS)‐stimulated and non‐stimulated monocyte supernatants by L929 bioassay.

Results

Tumor necrosis factor‐alpha and uric acid plasma levels were higher in PE than in GH pregnancies. In both hypertensive groups, these parameters positively correlated and were significantly more elevated than in NT and NP women. TNF‐α plasma levels and monocyte production were higher in hypertensive than in NT women during gestation, and significantly decreased at puerperium. Although decreased, TNF‐α release in LPS‐stimulated PE monocytes, was still significantly higher than in the other pregnant groups.

Conclusion

In vivo monocyte activation in GH and PE pregnant women was characterized by in vitro TNF‐α production. The fact that higher circulating concentrations of TNF‐α and uric acid were observed in PE than in GH suggests an association with disease severity.
Putative Predictors of Antibodies Against Follicle‐Stimulating Hormone in Female Infertility: A Study Based on In Vitro Fertilization Patients
Authors: Haller Kadri , Salumets Andres , Grigorova Marina , Talja Ija , Salur Liina , Béné Marie Christine , Laan Maris , Uibo Raivo
Published: February 2007

Problem

We have previously demonstrated the presence of naturally occurring antibodies against follicle‐stimulating hormone (FSH) in patients with endometriosis and polycystic ovary syndrome (PCOS). Here, we investigated the parameters associated with anti‐FSH antibodies in in vitro fertilization (IVF) patients.

Methods of study

The following parameters were studied in 135 patients: peripheral FSH levels, FSH β‐subunit gene (FSHB) haplotypes, history of previous IVF, and susceptibility to autoimmune reactions in general [seven common autoantibodies (against nuclear antigens on human and rodent substrates, smooth muscle, gastric parietal cells, β2‐glycoprotein I, cardiolipin, and thyroid peroxidase) and HLA‐DQB1 alleles].

Results

Although the anti‐FSH levels were higher in patients when compared with controls, those higher levels were not associated with FSHB haplotypes. The anti‐FSH IgM associated with (i) the levels of FSH in women with male and tubal factor infertility; (ii) the history of IVF in patients with PCOS, endometriosis, and unexplained infertility; and (iii) the production of common autoantibodies among all IVF patients. The anti‐FSH IgA associated with HLA‐DQB1*03. The anti‐FSH IgG correlated with the values of anti‐FSH IgA and IgM.

Conclusion

Anti‐FSH may be naturally occurring antibodies associated with peripheral FSH concentrations, but increased in infertile women with dysregulation of immune reactions and repeatedly performed IVF.
Use of and satisfaction with Community Aged Care Packages in the eastern suburbs of Sydney
Authors: Thomas Marlene , Woodhouse Brian , Rees‐Mackenzie Jenny , Jeon Yun‐Hee
Published: February 2007

Objective: The pilot study aimed to examine the accessibility and the flexibility of the Community Aged Care Package (CACP) program, and provide recommendations for further improvement.

Method: Data were collected using structured interviews with 80 CACP recipients, and mail surveys with nine service coordinators of CACP services. Descriptive statistics and χ2 analysis were used for quantitative information, and thematic analysis for qualitative data.

Results: CACPs were utilised more frequently and for longer periods by clients with English‐speaking backgrounds and those living alone. The average level of client satisfaction with CACP was high, over 62% rating extremely satisfied. Participants expressed concerns related to CACPs including inflexibility, lack of communication between service providers and other health services, poor continuity and quality of care, inadequate funding, problems with recruitment, retention and support for staff.

Conclusion: While the clients’ overall satisfaction levels were rated high, qualitative information suggested a need for improvement of the current delivery of the CACP program.
IκBα promoter polymorphisms in patients with rheumatoid arthritis
Authors: Lin C‐H. , Ou T‐T. , Wu C‐C. , Tsai W‐C. , Liu H‐W. , Yen J‐H.
Published: February 2007

To investigate the role of inhibitor of κBα promoter polymorphisms in the pathogenesis of rheumatoid arthritis (RA), 140 patients with RA and 115 healthy controls were enrolled in this study. The IκBα promoter polymorphisms were determined using the polymerase chain reaction/restriction fragment length polymorphisms method. In comparison with IκBα−826 C/C, the genotype frequency of IκBα−826 C/T was significantly higher in the patients with RA than that of the controls (P = 0.009, OR = 2.0, 95% CI = 1.2–3.4). The allele frequency of IκBα−826 T was also significantly increased in patients with RA when compared with that of the controls (P = 0.027, OR = 1.6, 95% CI = 1.1–2.4). In comparison with IκBα−550 A/A, the genotype frequency of IκBα−550 A/T was significantly decreased in patients with RA when compared with that of the controls (P = 0.02, OR = 0.2, 95% CI = 0.06–0.8). The allele frequency of IκBα−550 A was significantly increased in patients with RA (P = 0.007, OR = 5.1, 95% = 1.4–18.2). This study also revealed that the IκBα−826 T −550 A −519 C haplotype was significantly increased in patients with RA in comparison to that of controls (P = 0.01, OR = 1.8, 95% CI = 1.1–2.8). The IκBα−826 T and −550 A alleles are associated with susceptibility to RA. Moreover, the IκBα−826 T −550 A −519 C haplotype is associated with susceptibility to RA in Taiwan.
Optimization and integration of trimethylsilane-based organosilicate glass and organofluorinated silicate glass dielectric thin films for Cu damascene process
Authors: Cheng Y. L. , Wang Y. L. , Hwang G. J. , Lee W. H. , O’Neill M. L. , Tang Allen , Wu C. L.
Published: February 2007

Integration of organosilicate glass (OSG) and organofluorinated silicate glass (OFSG) low-k materials deposited using trimethylsilane precursor as interlayer dielectric (ILD) was investigated in this study. Although the full OSG structure showed the lowest capacitance, this structure suffered the integrated challenge, such as the poor deposition uniformity, chemical ashing damage, and cracking issues. Thus, a hybrid ILD scheme is introduced, which is stacked with OSG and OFSG dielectrics to address these issues. The process for this hybrid ILD scheme was optimized for deposition uniformity, permittivity, mechanical strength, low-k material damage, and electromigration resistance. An optimized ILD structure was integrated into 0.13μm Cu damascene process technology and showed much improvement compared to the full OSG or OFSG structure. The results of this study indicated that the hybrid structure which consists of the OSG and OFSG dielectrics can be successfully implemented in fully integrated interconnect structure.
Simple model for dielectrophoretic alignment of gallium nitride nanowires
Authors: Motayed Abhishek , He Maoqi , Davydov Albert V. , Melngailis John , Mohammad S. N.
Published: February 2007

A model describing the dielectrophoretic alignment of gallium nitride nanowires suspended in a solvent is presented here. The variations in the dielectrophoretic forces experienced by nanowires in different dispersing solvents have been calculated. It is shown that the relative sizes of the nanowires with respect to the spherical microparticles play a major role in the dielectrophoretic forces experienced by them.
A comparison of two design methods for unpaved roads reinforced with geogrids
Authors: Lyons C Kevin , Fannin Jonathan
Published: February 2007

The design of geosynthetic-reinforced unpaved roads is based on a limit equilibrium analysis of bearing capacity at the ultimate limit state. Two semiempirical design methods are shown to be predicated on a common fundamental relation, but differ in the parameterization of input groups. Degradation of subgrade strength with repeated loading is well characterized by each design method and is believed to be of primary importance in obtaining good agreement between the result from analysis and the observed response to field trafficking. The two design methods were found to require different values for the undrained shear strength of the subgrade, which is partly attributed to the significantly different load spread angles used to model the effect of the base course. Selection of the initial undrained shear strength deserves careful consideration in sensitive soils. In order to use one of the design methods, it is important to select this value so that it is consistent with the other parameter groups being used.Key words: bearing capacity, geogrid, unpaved road.
GUARANTEED TERMINATION IN THE VERIFICATION OF LTL PROPERTIES OF NON-LINEAR ROBUST DISCRETE TIME HYBRID SYSTEMS
Authors: DAMM WERNER , PINTO GUILHERME , RATSCHAN STEFAN
Published: February 2007

We present a novel approach to the automatic verification and falsification of LTL requirements of non-linear discrete-time hybrid systems. The verification tool uses an interval-based constraint solver for non-linear robust constraints to compute incrementally refined abstractions. Although the problem is in general undecidable, we prove termination of abstraction refinement based verification and falsification of such properties for the class of non-linear robust discrete-time hybrid systems. We argue, that—in industrial practice—safety critical control applications give rise to hybrid systems that are robust. We give first results on the application of this approach to a variant of an aircraft collision avoidance protocol.
THE D0L ω-EQUIVALENCE PROBLEM
Authors: HONKALA JUHA
Published: February 2007

Culik II and Harju have shown that the ω-equivalence problem is decidable for D0L systems. We give a new proof of this result.
Deep Platinum Deposition on Medium and highly doped N-type Porous Silicon by Immersion Plating
Authors: Brito-Neto Jose Geraldo A. , Araki Shintaro , Hayase Masanori
Published: February 2007

Porous platinum layers were synthesized on highly doped n-type porous silicon by immersion plating in HF-containing hexachloroplatinate solutions. Scanning electron microscopy showed that the deposits attained up to 8 um depth. The achieved platinum deposits have a random pore structure whereas the original porous silicon substrates show an organized honeycomb-like parallel pore array. Electron probe microanalysis measurements showed that the deposits have very good in-depth homogeneity, indicating also that almost all silicon originally presented was etched away by platinum. The electrochemically active surface area of the platinum deposits was determined to be on the order of 80 m^2/cm^3 by cyclic voltammetry.
Electrically Mediated Copper Electrodeposition for Interconnect Applications
Authors: McCrabb Heather , Taylor E.J. , Carpio Ron
Published: February 2007

The semiconductor industry's scaling towards smaller interconnect features on semiconductor wafers is anticipated to exacerbate the problems associated with additive incorporation and breakdown. As an alternative to traditional electrodeposition processes that involve direct current plating in conjunction with accelerator, suppressor and leveler chemistries to achieve defect-free metallization of sub-micron features, this paper investigates the electrodeposition of copper from a single component copper plating bath containing only the polyethylene glycol (PEG) - chloride suppressor system. Copper metallization of micron and sub-micron size interconnect features was achieved using an electrically mediated electrodeposition process that relies on pulse reverse waveforms to control the current distribution at the microscale. Due to the absence of the accelerating chemistries, the momentum bump that is formed over high density arrays of sub-micron features is eliminated and different feature sizes can be filled in the same processing step through the optimization of sequenced waveforms in a simplified plating chemistry.
In Situ Stress Measurements During Copper Deposition
Authors: Stafford Gery R. , Beauchamp Carlos , Kongstein Ole
Published: February 2007

In situ stress measurements were made during copper electrodeposition onto (111)-textured Au from acidic sulfate electrolyte using the wafer curvature method. During the bulk deposition of Cu, there is a rapid increase in tensile stress during the first 20 nm of growth that we attribute to nuclei coalescence and grain boundary formation. The magnitude of the tensile stress as well as the film thickness at which the maximum stress occurs are both dependent upon the electrode potential due to its influence on the nucleation density. As the deposit thickens, the average film stress decreases rather quickly and can become compressive in deposits formed at small deposition overpotentials. Both of these observations are consistent with stress-generation models proposed in the literature. When deposition is interrupted, both tensile and compressive components of the stress relax but are quickly re-established when deposition is resumed, suggesting that the relaxation is reversible and not due to irreversible microstructural changes.
Simulation and Experimental Results for Copper Deposition in a Moving Wafer Tool to Minimize Terminal Effects
Authors: McCrabb Heather , Lee Jong-Min , Taylor E.J. , Carpio Ron
Published: February 2007

Copper electrodepositon onto 200 mm silicon wafers containing a 30 nm ruthenium (Ru) barrier layer was studied using a novel horizontal research grade wafer processing tool. The wafer processing tool incorporates a virtual anode and a wafer holder that varies the wafer position vertically relative to the virtual anode opening during the plating process. The ability to change the distance between the wafer substrate and the virtual electrode opening during the plating process enables improved control of the dynamic current distribution across the wafer surface. The effect of the wafer position and wafer movement on the current distribution during the copper deposition process onto resistive Ru barrier layers is examined using numerical analysis. Experimental data for copper deposition onto the Ru barrier layer is compared with the simulation results.
Copper Electrodeposition on Diffusion Barrier Films- A Literature Review
Authors: Pesic Batric
Published: February 2007

Because of its lower electrical and significantly better electromigration and stress migration resistance, copper has emerged as a metal of choice for interconnect fabrication. Among various technologies for copper deposition, the fabrication based on electrochemical deposition has become an industrial standard. However, the electrochemical deposition of copper faces new challenges due to the requirements for the smaller interconnect size, which in turn mandates thinner seed and barrier layers. In this context, the interconnect fabrication issues can be subcategorized in two distinct areas: (1) the relevant properties (resistivity, adhesion, electromigration) of interconnects, specifically those at the barrier/copper interface, and (2) the electrodeposition methods. This paper reviews both areas.
Back-End Copper Metallization for Advanced Packaging
Authors: Kim Bioh , Sharbono Charles , Ritzdorf Tom , Schmauch Dan
Published: February 2007

We developed various back-end copper processes for advanced packaging. Deposition conditions for bump applications were optimized to achieve a high deposition rate (3-4um/min) due to thick deposits and simple die patterns. Bath composition, waveform, deposit thickness, and mask parameters (open area and resist thickness) significantly impact surface properties at high-rate deposition. For other through-mask applications such as redistribution lines and embedded passives, we modified process conditions and lowered deposition rate (1- 2um/min) to obtain better within-die thickness uniformity. Pattern complexity, deposition rate, waveform, and bath conductivity drastically impact within-die thickness distribution. For through-silicon-via applications, we investigated the impact of varying deposition conditions on the filling profile. Reducing current crowding at the via mouth and mass transfer limitations at the via bottom is critical in achieving void-free filling. Void-free filling can be achieved only with a proper combination of surface wettability, seed conformality, bath composition, waveform, current density, and flow conditions.
Epitaxial Growth of Cu on Au(111) and Ag (111) by Surface Limited Redox Replacement
Authors: Dimitrov Nikolay G. , Viyannalage Lasantha , Vasilic Rastko
Published: February 2007

The growth of ultra thin copper films by surface limited redox replacement is discussed and experimentally illustrated. Cyclic Voltammetry and Scanning Tunneling Microscopy are employed to carry out and monitor the two-dimensional growth of up to 60 monolayers of Cu on Ag (111) and Au(111) by multiple redox replacement of underpotentially deposited Pb used as a sacrificial metal. Open circuit potential monitoring during the replacement reaction is used to control the completion of each deposition event. Anodic film stripping is performed to determine the film thickness and calculate the yield of the employed deposition strategy. The excellent film quality is manifested by a distinct peak voltammetry and ascertained by in- situ STM showing uniform surface morphology maintained during the entire growth process.
Electrodeposition of Serpentine CoCu/Cu Multilayered GMR Micro-device
Authors: Podlaha Elizabeth J. , Li Yutong , Moldovan M. , Young D. P. , Wang W. , Fan Ruili
Published: February 2007

A serpentine microdevice consisting of Co/Cu multilayers were galvanostatically electrodeposited onto a silicon substrate patterned via UV lithography in a two-step process. SEM was used to investigate the morphology of the deposit and edge effect regions were identified. The magnetoresistance was measured with the current perpendicular to the magnetic field along the long length area and parallel to the magnetic field at the short length area due to the serpentine shape. The influence of line width, bilayer number and a pulse train scheme on the giant magnetoresistive property of patterned thin films were examined.
Gold Electrodeposition On Silicon
Authors: Huang Qiang , Deligianni Hariklia (Lili) , Romankiw Lubomyr
Published: February 2007

Gold electrodeposition on n-Si (100) surface was investigated by performing a detailed study on nucleation and growth. The effects of additives such as thallium, applied potential and current density, and bulk gold concentration were studied. With addition of thallium in the solution, enhancement and inhibition of the gold deposition were observed at low potential and high potential, respectively. The nucleation of gold on Si was found to depend on the Au concentration and applied potential as well as the Tl+ addition. At low current densities Tl+ increases the Au nuclei size and decreases the density by catalyzing the nuclei growth. At high current densities, an opposite effect was observed. An adsorbed thallium intermediate species is proposed to explain both the catalytic and suppressive effects.
Electrochemical Mechanical Planarization (eCMP) of Copper Thin Films
Authors: Aksu Serdar , Emesh Ismail , Uzoh Cyprian , Basol Bulent
Published: February 2007

A novel Electrochemical Mechanical Planarization (eCMP) process was developed and integrated on the copper plating platform to meet the stringent technical requirements including higher planarization efficiency, higher throughput at lower down force and lower defectivity for the manufacture of devices at 65 nm and beyond technology nodes. In the integrated system, following the electroplating process, the wafer is transferred to the planarization module where the bulk of copper is polished and planarized at a high rate, leaving a thin, planar copper film. It was determined that the resulting planar thin film enables conventional chemical mechanical polishing to clear the remaining copper and barrier with low dishing and erosion. The planarization mechanism of the eCMP process was explained on the basis of electrochemical experimental results.
Small-Batch Reactor Development for Silicon Epitaxial Film Growth Based on Theory of Transport Phenomena
Authors: Habuka Hitoshi , Sakakibara Hisashi , Kawaoka Masayuki , Arimura Kenichi , Scudder Lance , Okabe Akira
Published: February 2007

Transport phenomena and surface reaction rate in the small- batch horizontal cold-wall silicon epitaxial reactor at atmospheric pressure are studied using computational fluid dynamics. According to the effect and the role of the gas inlet in a trichlorosilane-hydrogen system, the combination of two or three gas inlet zones is considered to achieve the uniform epitaxial film profile. The susceptor rotation rate is also a parameter to adjust the film thickness profile.
Liquid delivery MOCVD of Ruthenium Films from Ru(EtCp)2 with Toluene Solvent
Authors: Lisker Marco , Hur'yeva Tetyana , Burte Edmund
Published: February 2007

Pure ruthenium thin films were prepared using bis (ethylcyclopentadienyl)ruthenium (Ru(EtCp)2) with toluene solvent by liquid delivery MOCVD. The deposition of Ru thin films was carried out on various substrates at temperatures of 330 - 460 {degree sign}C via the oxygen-assisted pyrolysis of Ru(EtCp)2. The Ru single phase could be obtained at all growth conditions. The reaction kinetics, film composition, film morphology, mechanical and electrical properties of deposited Ru films were investigated. Obtained films showed low stress values of about 70 MPa and a low resistivity of about 20 µW×cm which offers the application for storage capacitor electrodes.
The Influence of the Deposition and Annealing Temperatures on the Structure and Properties of Zirconium Oxide
Authors: Lisker Marco , Silinskas Mindaugas , Matichyn Serhiy , Burte Edmund
Published: February 2007

ZrO2 thin films were deposited by atomic vapor deposition (AVD) using Zr[OC(CH3)3]4 as precursor. The maximum growth rate (~7 nm/min) and the strongest crystalline phase with preferential tetragonal/cubic orientation were obtained at 400{degree sign} C. Growth rate and crystallinity dropped down with increasing or decreasing deposition temperature. Additionally, the increase of the deposition temperature changed the crystalline ZrO2 phase from cubic/tetragonal to monoclinic. Annealing reduced the cubic/tetragonal phase and enhanced the monoclinic one. The values of the dielectric constant (up to 32) varied depending on the deposition temperature, film thickness, and annealing temperature. Leakage current density measurements showed typical values of about 2×10-7 Acm-2 at 1×106 Vcm-1. The midgap density of interface states was Dit = 5×1011 eV-1cm- 2. Due to annealing the leakage current density and the density of interface states were lowered to 10-7 A/cm-2 and to 1010 eV-1cm-2, respectively. However, the dielectric constant also decreased.
Characterisation of High Temperature CVD Iron
Authors: Low Yee Hooi , Montgomery John H. , Gamble Harold S.
Published: February 2007

The growth and analysis of iron thin films by low-pressure chemical vapor deposition (CVD) from a liquid source precursor iron pentacarbonyl (Fe(CO)5) is reported. The layers were deposited at 200-400C and 0.75 mbar on 100mm oxidised silicon substrates. Hydrogen was used as diluent gas. Layers between 120nm and 245nm were achieved for 20-minute process runs. Lower temperature layers were more porous. The resistivity of a 120nm thick layer deposited at 300C was 20 micro-ohm-cm. X- ray diffraction (XRD) analysis yielded peaks of α-Fe 110 & 200 body-centered-cubic (bcc) lattice. The highest magnetisation value was 1518emu/cm3 for the 300C layer. The lowest coercivity was 31Oe. Conformal coating of CVD Iron is demonstrated.
Langmuir-probe Characterization of an Inductively-Coupled Remote Plasma System intended for CVD and ALD
Authors: Boogaard Arjen , Kovalgin Alexey , Aarnink Tom , Wolters Rob , Holleman Jisk , Brunets Ihor , Schmitz Jurriaan
Published: February 2007

We measured electron density and electron energy distribution function (EEDF) vertically through our reactor for a range of process conditions and for various gases. The EEDF of Ar plasma could largely be described by the Maxwell-Boltzmann distribution function, but it also contained a fraction (~ 1E- 03) of electrons which were faster (20-40 eV). At low pressures (6.8-11 μbar), the fast-electron tail shifted to higher energies (Emax ~ 50 eV) as we measured more towards the chuck. The fast-electron tail shifted to lower energies (Emax ~ 30 eV) when we increased pressure to 120 μbar or applied an axial magnetic field of 9.5 μT. Addition of small amounts of N2 (1- 10%) or N2O (5%) to Ar plasma lowered the total density of slow electrons (approx. by a factor of two) but did not change the shape of the fast-electron tail of the EEDF. The ionization degree of Ar-plasma increased from 2.5E-04 to 5E-04 when a magnetic field of 9.5 μT was applied.
Surface Characterization Of Chromium Oxide Thin Films in Dependence on CVD Growth Process Parameters
Authors: Gesheva Kostadinka A. , Ivanova Tatyana , Szekeres Anna Maria , Trofimov Oleg
Published: February 2007

Thin chromium oxide films were deposited by low-temperature carbonyl CVD process at atmospheric pressure. The deposition temperature of 200oC was found for optimal leading to obtaining thin films with a good adhesion to glass and silicon substrates. With respect to electrochromic applications, the electrode surface is a main factor for ion-intercalation processes determining the electrochromic device performance. The aim of the present paper is investigation of the surface of chromium oxide films by atomic force microscopy (AFM). Additional surface characterization is derived from spectral ellipsometric measurements.
Non-Conventional Tight-Binding Molecular Dynamics Simulation of Bare Silicon and Silicon-Hydrogen Clusters
Authors: Swihart M. T. , Khakimov Z.M. , Sulaymanov N.T. , Umarova F.T. , Mukhtarov A.P. , Tereshchuk P.L.
Published: February 2007

Bare silicon clusters with non-diamond and diamond-core structures, as well as silicon-hydrogen clusters, were simulated using a recently developed non-conventional tight- binding molecular-dynamics method. In the range of cluster sizes considered (up to 71 atoms), clusters with a diamond core were found to be energetically unfavorable compared to representative non-diamond clusters from a regular, one- dimensional growth pattern, proposed by the authors. It is shown that the method used here can reproduce the results of high-level ab initio methods including multi-level multi-step methods such as G3/B3LYP.
Determination of the Rate Constants of Hydrogen Evolution and Permeation into Steel in Acidic Sulphate Solutions by IPZ method
Authors: Tsygankova Liudmila , Kosyanenko Evgeny
Published: February 2007

Hydrogen absorption into steel membrane was studied using an electrochemical hydrogen permeation technique. The investigations were conducted in the H2SO4 + Na2SO4 solutions with the constant ionic strength equal to 1 and pH equal to 1.80 and 1.13. The influence of CNS- anions has been studied. The Iyer, Pickering, Zamanzadeh (IPZ) analysis of the measured steady-state hydrogen permeation rates gives the rate constants of the steps of the HER, hydrogen surface coverage OH, exchange current density, io, and kinetic-diffusion constant. The kinetic parameters of the HER have been estimated at a constant potential and a constant hydrogen overpotential. These data testify about the Volmer rate determining step (rds) in the HER.
Localized Corrosion of Silicon-Reinforced Aluminum Composites in Na2SO4 Solution
Authors: Ding Hongbo , Hihara Lloyd H.
Published: February 2007

Localized corrosion formed on an Al-based metal-matrix composite (MMC) reinforced with 40 wt% Si particles in an air-exposed 0.5 M Na2SO4 solution. Scanning vibrating electrode technique revealed that the net currents over the localized corrosion region were cathodic. Scanning ion-selective electrode technique revealed that the solution near the localized corrosion region was alkalized. Scanning electron microscopy indicated that corrosion initiated around Fe-containing intermetallic particles, which serve as cathodic sites. It is hypothesized that during the processing of the Al/Si MMC, inter-diffusion causes Al atoms to diffuse into Si particles forming a layer of highly p-doped Si at the Al/Si interface. Thus, following the immersion of the MMC into the Na2SO4 solution, at the sites adjacent to the Fe-containing intermetallic particles where the Al matrix dissolved, highly p-doped Si surfaces were exposed to the solution. The highly p-doped surfaces can therefore serve as cathodic sites and exacerbate corrosion.
Thermal Degradation of Selected Alloys for SOFC Interconnectors
Authors: Mustala Sanni A. , Veivo Juha , Auerkari Pertti , Kiviaho Jari
Published: February 2007

Oxide growth and thermal degradation of three ferritic SOFC interconnector alloys have been investigated. The materials included a standard grade (alloy 430) and two alloys (Crofer 22 APU, ZMG 232) specifically designed for interconnector service. All alloys appear to follow parabolic oxidation up to 500 h at 740{degree sign}C in air. During oxidation, a consistent decrease of iron and increase of chromium and manganese were observed in the surface oxide. Some chromium transport was detected on the cathode side surface of the cell after 500 h at 740{degree sign}C. The results emphasise the importance of appropriate coating of the interconnectors, to prevent chromium poisoning on the cathode. A natural coating material would be similar or compatible with the ceramic cathode. Such a coating also has the additional advantage that simpler and cheaper steel grades could be used as the interconnector material.
Dependence of Energy and Electron Transfer on Length and Configuration of Bridged Oligosilane in Porphyrin-C60 Dyad
Authors: Ito O. , Sasaki Mikio , Tsuji Hayato , Shibano Yuki , Araki Yasuyuki , Tamao Kohei
Published: February 2007

We have investigated the photophysical properties of the oligosilane-bridged zinc porphyrin-fullerene[60] dyads. Dependence of the rate of the relaxation processes of the singlet-excited state of the ZnP moiety of the dyads on the oligosilane linker was mostly ascribable to the conformational differences of the silicon chain. The charge-separated state with sub-microsecond lifetime was observed in the time-resolved absorption measurements of benzonitrile solution of the dyads. The lifetime of the radical-ion pair scarcely depended on the length and little on the conformation of the oligosilane linkage, which suggests that the super-exchange mechanism disciplines the charge recombination process.
Uses of Single Wall Carbon Nanotube Salts in Organic Syntheses
Authors: Billups W E. , Liang Feng , Chattopadhyay Jayanta , Beach Jonathan
Published: February 2007

Reductive alkylation of single-walled carbon nanotubes (SWNTs) using alkali metals and alkyl halides in liquid ammonia yields debundled sidewall-functionalized nanotubes that are soluble in common organic solvents. GC-MS analysis of the byproduct hydrocarbons demonstrates that alkyl radicals are intermediates in the alkylation step. Electron transfer from lithium to the SWNTs was investigated by in-situ monitoring of the Raman spectrum as lithium was added incrementally to a dispersion of the SWNTs in liquid ammonia. The electron/lithium uptake saturation level was determined to be ~C2/Li. This is similar to C2F, which is the limit found previously for direct fluorination of SWNTs. TGA-FTIR analyses of samples prepared from sodium and potassium revealed radically different thermal behavior during detachment of the alkyl groups. These differences can be observed by analysis of the solid-state 13C NMR spectra of dodecylated SWNTs and may indicate the relative amounts of 1,2- and 1,4-addition products. SWNTs that have been functionalized by carboxylic acid groups can be PEGylated by H2N-mPEG-OMe (MW = 5000) to yield water soluble SWNTs.
An Alternative Approach for Separating Metallic Nitride Fullerenes (MNFs) from Nanomaterial Mixtures
Authors: Stevenson Steven , Yu Helen , Heaps David T. , Stephen Ryan R. , Coumbe Curtis , Harich Kim , Carpenter Katie , Phillips Janice Paige
Published: February 2007

Metallic nitride fullerenes (MNFs) are of interest to fundamental studies and applications. However, MNF sample availability for these studies has been limited. The lack of samples is related to the currently used chromatographic (HPLC) separation protocol, a tedious approach that is solvent intensive, expensive, and has a limited throughput. To address these drawbacks, we developed an alternative method (non-chromatographic) for removing contaminant C60 and C70 empty-cage fullerenes and other classical metallofullerenes (i.e. non-nitrogen containing endohedrals) from soot extracts. Specifically, we present a purification approach based on differences of cage reactivity of MNFs versus other fullerenes. Results indicate that reactive silica can preferentially bind to contaminant fullerenes and metallofullerenes using our Stir and Filter Approach (SAFA). With this process, fullerene contaminants are immobilized onto reactive silica, while unreacted MNFs remain in the filtrate. In this manner, purified samples of Sc3N@C80 are readily obtained.
Non-Destructive Extraction of Semiconducting Single Walled Carbon Nanotubes by Wrapping with Flexible Porphyrin Polypeptides and the Supramolecular Photodynamics
Authors: Saito Kenji , Troiani Vincent , Qiu Hongjin , Solladie N. , Sakata Takao , Mori Hirotaro , Araki Yasuyuki , Ito O. , Fukuzumi S.
Published: February 2007

Porphyrin-peptide hexadecamer molecules form supramolecular nanohybrids preferentially with semiconducting carbon nanotubes (SWCNTs) by wrapping of peptidic backbone in P(H2P)16 and π-π interaction between porphyrins and nanotubes. Such supramolecular nanohybrid formation results in de-bundling of nanotubes and extraction of semiconducting SWCNTs from starting purified SWCNTs as indicated by the high-resolution transmission electron microscopy (HRTEM) image and the Raman spectrum of SWCNTs wrapped with P(H2P)16, respectively. The photoexcitation of the supramolecular nanohybrids affords the long-lived charge-separated state via photoinduced electron transfer from P(H2P)16 to SWCNTs.
Determination of Cr(VI) in Water with Amperometric Detection at Conductive Polymer Electrodes
Authors: Stotter Jason M. , Carter Michael T.
Published: February 2007

Electrochemical sensors can provide sensitive detection for monitoring of contaminant leakage from storage areas, plume movement in ground and surface water, and residual contamination following cleanup using inexpensive, portable equipment. While hexavalent chromium, Cr(VI), exhibits slow electron transfer kinetics at most electrodes, it is catalytically reduced by the reduced form of polyaniline (PANI). In the present device, the reduction of PANI oxidized by Cr(VI) provides an analytical signal proportional to Cr(VI) concentration in aqueous samples, allowing amperometric detection of Cr(VI) with ppb detection limits. Calibration curves, limits of detection, S/N ratios, and effects of interferences on the sensor response in a flow injection analysis configuration are presented.
Determination of Water in 1-Ethyl-3-methylimidazolium tetrafluoroborate
Authors: Cheek Graham T. , O'Grady William , Lawrence Steven
Published: February 2007

Determination of water in 1-ethyl-3-methylimidazolium tetrafluoroborate has been carried out using both electrochemical and infrared spectroscopic methods. At platinum electrodes, voltammetric responses for water oxidation and reduction have been used to prepare calibration curves. It has been found that the water oxidation current at +2.4V vs Ag/AgCl is suitable for water determination to at least 40 mM. Infrared spectroscopy of water in quartz cells in the OH stretching region revealed an IR feature at 3550 cm- 1 for water additions to 20 mM, with another feature at 3650 cm-1 appearing at higher water concentrations. For the low- frequency feature, a calibration curve is linear to 14 mM. Both electrochemical and IR methods provide a lower limit of detection of approximately 1 mM water in this ionic liquid.
Growth and Properties of Oxide Films on Platinum II. pH Dependence in Alkaline Solutions
Authors: Sun Adan , Macdonald Digby D.
Published: February 2007

The kinetics of growth of the oxide film on platinum has been studied in alkaline solutions as a function of pH. The experimental data confirm the existence of steady states in the current and thickness. Diagnostic criteria for the dependence of the steady state current and thickness on applied potential and pH are derived from the PDM, in which the point defects in the barrier layer are postulated to be cation vacancies, cation interstitials, and oxygen vacancies. The steady state thickness is then predicted to vary linearly with the applied potential and pH. These predictions are in good agreement with the experimental findings. The kinetic order of the barrier layer dissolution reaction with respect to the hydrogen ion concentration in the alkaline solutions is found to be negative, which indicates that the platinate anion might be formed during film dissolution.
Kinetic and Thermodynamic Parameters of Hydrogen Sorption in Pd, Pd-Pt and on Pt
Authors: Lasia A. , Jurczakowski Rafal , Losiewicz Bozena
Published: February 2007

Hydrogen may be adsorbed on Pt while it can be adsorbed on and absorbed in Pd and its alloys. Kinetics of hydrogen adsorption on Pt and Pd-Pt alloys is very fast but it is much slower on Pd. The kinetics of these reactions was studied using the electrochemical impedance spectroscopy, EIS, with a twin electrode configuration. The studies in the presence of crystal violet, which poisons hydrogen adsorption and accelerates hydrogen absorption, indicate that the absorption process proceeds via direct absorption mechanism.
Electrochemical Synthesis of Silver and Gold Nanoparticles
Authors: Cojocaru Paula , Vicenzo Antonello , Cavallotti Pietro Luigi
Published: February 2007

Silver and gold nanoparticles were prepared by electrodeposition from sulfite based solutions as a possible alternative to the standard chemistry usually proposed in the literature for electrochemical deposition of silver and gold nanoparticles. The voltammetric behavior of the electrolytes is studied at glassy carbon and titanium surface, showing that kinetic control plays a role in the discharge of the sulfite complex of either silver or gold. The formation of particles on titanium substrate and their morphological features are examined, changing the deposition conditions, pulse potential and duration or potential scan rate. Remarkable differences in the formation of Ag and Au particles on the titanium substrate are highlighted: growth and aggregation characterize the formation of Ag particles; on the contrary, Au particles are deposited with high nucleation density and uniform size distribution, though the particle dimension is rather on the mesoscale than in the nanoscale dimension.
The Visible Photocatalysis Properties of Nitrogen-doped TiO2 Thin Film
Authors: Lu Yang-Ming , Liu Chung-Kai , Huang Chao-Ming
Published: February 2007

Titanium oxide films with different amounts of nitrogen doping have been deposited by the DC magnetron sputtering technique. The characteristics of the TiO2 films, such as crystal structures, chemical compositions, analyses, surface morphologies and photocatalyst effects were examined. The anatase phase of pure titanium oxide was observed to be deposited on the Al substrate at 250°C, while the mixed phase of anatase and rutile appeared as the temperature was increased to 350°C. The intensity of the anatase phase (101) was enhanced after nitrogen-doping the TiO2 films. A daylight lamp was used as the visible light source to analyze the IPA decomposition reaction on the surface of the TiO2 films. The nitrogen doped TiO2 films had good photocatalyst properties and followed the first-order kinetic model regarding decomposition of IPA. The apparent first-order rate constant of the TiO2 films with nitrogen doping was about 2.6 times larger than that of undoped TiO2 films. The results show that nitrogen doped TiO2 films can be active under visible light radiation.