bluuebunny/crossref_metadata_2025 huggingface dataset:
Overactive bladder syndrome in older people
Authors: Wagg Adrian S. , Cardozo Linda , Chapple Christopher , De Ridder Dirk , Kelleher Con , Kirby Michael , Milsom Ian , Vierhout Mark ,   the Overactive Bladder Faculty
Published: February 2007

The overactive bladder symptom complex (OAB) is the commonest cause of urinary incontinence in older people, and is usually due to underlying detrusor overactivity, and as such is a treatable condition. Older people are a heterogeneous group, which includes fit community‐dwelling individuals and those with significant medical comorbidity; thus the requirements of care for this group are many and varied. The International Continence Society definition of the frail elderly, those aged >65 years with continence problems, who by virtue of comorbidity are house‐bound or living in an institution, is clearly not applicable to all. However, many conditions begin to appear in later life and practitioners need to be aware of the need to manage these, and their treatment, when dealing with older people. Studies of medication for OAB have included the elderly and there is evidence of an equivalent benefit in younger people. The impact of treatment on the cognitively impaired and those receiving acetylcholinesterase inhibitors is discussed.
A genetic algorithm for the partial binary constraint satisfaction problem: an application to a frequency assignment problem
Authors: Kolen Antoon
Published: February 2007

We describe a genetic algorithm for the partial constraint satisfaction problem. The typical elements of a genetic algorithm, selection, mutation and cross‐over, are filled in with combinatorial ideas. For instance, cross‐over of two solutions is performed by taking the one or two domain elements in the solutions of each of the variables as the complete domain of the variable. Then a branch‐and‐bound method is used for solving this small instance. When tested on a class of frequency assignment problems this genetic algorithm produced the best known solutions for all test problems. This feeds the idea that combinatorial ideas may well be useful in genetic algorithms.
THE EFFECTS OF FISCAL SHOCKS ON CONSUMPTION: RECONCILING THEORY AND DATA*
Authors: GANELLI GIOVANNI
Published: February 2007

Recent research has stressed the inconsistency between empirical evidence and the theoretical prediction of both the standard real business cycle and the New Keynesian models regarding the impact of fiscal shocks on consumption. Some authors have attempted to bridge this gap by relying on assumptions about the effects of government spending on preferences and production, or on deviations from the intertemporal optimizing framework. In this paper we follow a different route. We show that introducing at the same time imperfect competition, sticky prices and deviations from Ricardian equivalence through an overlapping generations model helps to solve the inconsistency between theory and data. Our paper can also be seen in the light of the classic controversy between Keynesians and monetarists on the effectiveness of fiscal policy. From this angle, our model can be considered a reincarnation of the classic work of Blinder and Solow (Journal of Public Economics, Vol. 2 (1973), pp. 319–337).
STRATEGIC CONTRACTS VERSUS MULTIPLE PLANTS: LOCATION UNDER SEQUENTIAL ENTRY*
Authors: ROTHSCHILD R. , HEYWOOD JOHN S. , MONACO KRISTEN
Published: February 2007

In this paper we explore the concept of a ‘strategic contract’ between two of three entrants that arrive sequentially in a spatial market and practise discriminatory pricing. We compare our results with those arising when two firms merge to create two plants. Although this second problem is superficially similar to the first, the underlying behavior and implications differ in crucial respects. The consequences, in terms of a variety of measures of welfare, of all of our results are demonstrated. We also consider the implications of the results for the so‐called ‘merger paradox’.
Quadratic Engel Curves with Measurement Error: Evidence from a Budget Survey*
Authors: Kedir Abbi , Girma Sourafel
Published: February 2007

This paper examines the importance of accounting for measurement error in total expenditure in the estimation of Engel curves, based on the 1994 Ethiopian Urban Household Survey. Using Lewbel's [Review of Economics and Statistics (1996), Vol. 78, pp. 718–725] estimator for demand models with correlated measurement errors in the dependent and independent variables, we find robust evidence of a quadratic relationship between food share and total expenditure in the capital city, and significant biases in various estimators that do not correct for correlated measurement errors.
MARKET TRANSACTION COSTS IN INDUSTRIALIZATION AND DEMOGRAPHIC TRANSITION*
Authors: Davis Lewis S.
Published: February 2007

Abstract.  This paper presents a unified theory of growth involving human capital accumulation, labour specialization, market expansion and falling fertility rates. The model suggests that these processes, often analysed separately, are intimately linked. The accumulation of specialized human capital increases the gains to labour specialization, leading agents to increase their participation in markets and reduce time spent at home. This raises the opportunity cost of child raising, lowering fertility rates. The model suggests a central role for market transaction costs in determining the timing and rate of fertility declines linked to rising income.
Prevalence of childhood acne, ephelides, warts, atopic dermatitis, psoriasis, alopecia areata and keloid in Kaohsiung County, Taiwan: a community‐based clinical survey
Authors: Yang Y‐C , Cheng Y‐W , Lai C‐S , Chen W
Published: February 2007

Background  Epidemiological study on childhood dermatoses performed by direct inspection of dermatologists is limited.

Objective  To investigate the prevalence of selective childhood dermatoses in Taiwan.

Methods  In a cross‐sectional study carried out in June 2004, 4067 of 7851 children aged between 6 and 11 years living in the Kaohsiung County in south Taiwan were clinically surveyed and examined by two board‐certified dermatologists (response rate 52%), regarding the point prevalence of acne, ephelides, warts, atopic dermatitis (AD), psoriasis, alopecia areata (AA) and keloid.

Results  Acne vulgaris was found in girls and boys from the age of 6 and 7, respectively, with comedones being the earliest presentation. Ephelides were not infrequently observed in our children (prevalence rate 8.4%, 95% confidence interval, CI 7.9–9.3%). The prevalence of warts on hands was 2.4% (95% CI 1.9–2.9%). The prevalence of AD was 1.7% (95% CI 1.3–2.1%), without gender difference. There were only four cases of AA but no psoriasis was found. Keloid was identified in 13 boys and 10 girls, accounting for 0.6% (95% CI 0.598–0.602%) of the children.

Conclusion  Acne vulgaris is as common in Taiwan as in Western countries. Ephelides are not uncommon in our population with the main skin types III–IV. A clustered distribution of the wart infection was noted. The low prevalence of AD in Taiwan seems unaltered over the past decade. AA and psoriasis are rare in our series. Most keloids in our children are caused by BCG vaccination.
Assessing the Legitimacy of the EU's Treaty Revision Methods*
Authors: RISSE THOMAS , KLEINE MAREIKE
Published: February 2007

How legitimate are the EU's treaty revision procedures, that is, IGCs and the Convention? Since the rejection of the Constitutional Treaty the recurrence to intergovernmental procedures appears as one way out of the current dilemma. We argue instead that the Convention method is not to blame for the current crisis. On the contrary, it increases the legitimacy of EU constitutionalization considerably.
Commodity Currencies: Why Are Exchange Rate Futures Biased if Commodity Futures Are Not?*
Authors: KEARNS JONATHAN
Published: February 2007

This paper adds to the well‐documented puzzle of the forward bias of exchange rates. While the exchange rate of a small commodity‐exporting economy, such as Australia, can be closely tied to commodity prices, this paper demonstrates empirically that a portfolio of commodity futures exhibits little, if any, bias. A microfounded small open economy model is developed in which the exchange rate depends on export commodity prices. This is used to demonstrate how systematic expectation errors about the monetary process could cause the bias in exchange rate forwards when there is an absence of bias in commodity futures.
Are Nominal Exchange Rates and Price Levels Co‐Integrated? New Evidence from Threshold Autoregressive and Momentum‐Threshold Autoregressive Models*
Authors: NARAYAN PARESH KUMAR
Published: February 2007

The goal of this paper is to examine evidence for co‐integration between nominal exchange rates for Canada, the UK, Japan, Germany, Italy and France (G6) vis‐à‐vis the US dollar, and the relative price ratios using monthly data over the period 1973:01 to 1997:04. Motivated by the fact that exchange rate adjustment may be asymmetric, we allowed for asymmetric adjustment in exchange rates by using the threshold autoregressive model and the momentum threshold autoregressive model. We do not find any evidence of a co‐integrating relationship; hence, we fail to establish long‐run purchasing power parity.
Cumulative Irritancy Comparison of Topical Retinoid and Antimicrobial Combination Therapies
Authors: Dosik Jonathan S. , Gilbert Richard D. , Arsonnaud Stephanie
Published: February 2007

Background. The use of multiple topical drugs for the treatment of acne may cause elevated irritation. Therefore, the selection of a combination regimen should include a careful consideration of the irritation potential of the individual acne medications.

Objective and Methods. To compare the cumulative irritation potential of adapalene gel 0.1 %, tazarotene cream 0.05%, and tretinoin microsphere 0.04% when applied in combination with two benzoyl peroxide/clindamytin topical gels in 35 healthy subjects in a 3‐week, randomized, controlled study.

Results. The mean cumulative irritancy index of adapalene combinations was significantly lower relative to tretinoin and tazarotene regimens (all P<.01). Test areas exposed to tretinoin or tazarotene were also more likely to be discontinued for severe irritation than those exposed to adapalene. There were no serious adverse events. No significant difference in the irritancy potentials of tazarotene and tretinoin combination regimens was observed.

Conclusions. Adapalene gel 0.1% has tolerability superior to both tazarotene cream 0.05% and tretinoin microsphere 0.04% when used in topical combination therapy. In view of the lower irritation potential observed in this study, along with its demonstrated efficacy, adapalene gel 0.1% in combination with antimicrobial agents may be used as part of an aggressive treatment regimen for the management of acne.
A Possible Mechanism for Phenol‐Induced Pemphigus
Authors: Sarah Brenner , Vincenzo Ruocco , Eleonora Ruocco , Avigdor Srebrnik , Ilan Goldberg
Published: February 2007

A possible mechanism for phenol‐induced pemphigus lesions in genetically predisposed individuals is proposed that accounts for in vitro observations and cases of biochemical acantholysis, as well as the in vivo acantholysis in pemphigus induced by phenols. The mechanism involves the induction of interleukin‐ 1αand tumor necrosis factor‐α release by keratinocytes. These cytokines in turn have been shown to be involved in the regulation and synthesis of complement and proteases like plasminogen activator, which have been implicated in the pathogenesis of acantholysis in pemphigus vulgaris.
A Possible Additional Diagnostic Tool for Cutaneous Melanoma
Authors: Brenner Sarah
Published: February 2007

The rise in incidence of malignant melanoma and the dismal prognosis of late detection emphasize the need for early detection and recognition of the disease. The well‐known ABCD method for detection of melanoma has recently been revised by adding an “E” for changes in size, shape, color, crusting, itching, bleeding, and erythema. In an observational study, 8 of 14 (57%) melanoma patients exhibited a particular reddish hue to the skin adjacent to the melanoma, with no distinguishable borders. In another study, vascular endothelial growth factor was positive in biopsy specimens from 3 of 6 (50%) patients with erythema and in 4 of 7 (57%) patients without erythema. Platelet‐derived growth factor was positive in all 6 (100%) of the patients with erythema and in 4 of the 7 (57%) without erythema. This erythema can help alert the clinician to the presence of malignant melanoma and serve as a prognostic factor or an indicator of the efficacy of treatment.
Gelcasting of Alumina Using Epoxy Resin as a Gelling Agent
Authors: Mao Xiaojian , Shimai Shunzo , Dong Manjiang , Wang Shiwei
Published: February 2007

A water‐soluble epoxy resin and hardener system for gelcasting of ceramics was developed. Polymerization of the system is a nucleophilic addition reaction, and not affected by oxygen. Therefore, this gelcasting system can be carried out in an air atmosphere. The ceramic slurries were prepared by mixing the aqueous premix solution of epoxy resin with alumina powder and dispersant. For cross‐linking, a polyamine hardener was added. Both the rheological properties of the slurries and the gelling behaviors of the aqueous premix solutions were evaluated. The slurry with a solid loading of 80 wt% is optimized for gelcasting. The flexural strength of the sintered ceramics is 335±47 MPa with 98% of theoretical density.
On the Applicability of Secondary Dentin Formation to Radiological Age Estimation in Young Adults
Authors: Meinl Alexandra , Tangl Stefan , Pernicka Elisabeth , Fenes Caroline , Watzek Georg
Published: February 2007

ABSTRACT: The literature provides linear regression formulas for dental age estimation that is based on radiological two‐dimensional measurements of the pulp size. The aim of the present study was to explore whether the previously presented regression formulas could lead to statistically sound results and to appropriate repeatability when applied to young individuals. Orthopantomograms (OPGs) of 44 Austrian individuals, aged between 13 and 24 years, were selected at random. In accordance with the reported method, six teeth on each OPG were chosen to carry out the measurements. Statistical analysis was performed in order to assess the difference between the estimated and the true chronological age. The regression formulas reported by Kvaal et al. (1995) led to a consistent underestimation; the regression formulas reported by Paewinsky et al. (2005) resulted in a constant overestimation of age. The statistical analysis of intraobserver and interobserver variation revealed a variation width below 2%, respectively.
Comparison of Atherosclerotic Calcification Burden in Persons With the Cardiometabolic Syndrome and Diabetes
Authors: Wong Nathan D. , Gransar Heidi , Shaw Leslee J. , Polk Donna , Berman Daniel S.
Published: February 2007

The cardiometabolic syndrome (CMS) and diabetes are associated with higher cardiovascular risk. The authors compared the association of CMS risk factors and diabetes with coronary and aortic calcium. A total of 4468 adults (42% female) underwent computed tomography for determination of coronary artery calcium (CAC) and thoracic aortic calcium (TAC) and were classified according to the presence of diabetes mellitus (DM) and number of CMS risk factors. The prevalence of CAC ranged from 51% in men and 35% in women with neither DM nor CMS to 75% in men and 58% in women with both DM and CMS, whereas TAC ranged from 29% to 44% in men and 36% to 55% in women. Women with four or five CMS risk factors more often had CAC (53%) and TAC (51%) than those with DM without CMS (40% and 35%, respectively) (p<0.001 across all disease groups). Adjusted odds (and 95% confidence intervals) of CAC for those with three CMS risk factors, four CMS risk factors, DM without CMS, and DM with CMS vs. those without CMS were 1.14 (0.93–1.39), 1.46 (1.12–1.90), 1.59 (1.06–2.38), and 2.10 (1.52–2.90) for CAC and 1.14 (0.91–1.42), 1.03 (0.77–1.37), 1.03 (0.68–1.54), and 1.41 (1.03–1.92) for TAC. Multiple CMS risk factors are associated with increased CAC, but not TAC; DM with CMS has the highest prevalence of CAC and TAC.
Metabolic Inflexibility in Skeletal Muscle: A Prelude to the Cardiometabolic Syndrome?
Authors: Thyfault John P. , Rector R. Scott , Noland Robert C.
Published: February 2007

Peripheral insulin resistance, which is largely dependent on skeletal muscle, is closely linked to the development of the cardiometabolic syndrome. Metabolic flexibility is the capacity for skeletal muscle to acutely shift its reliance between lipids or glucose during fasting or postprandial conditions. Obese and insulin‐resistant individuals display elevated intramuscular lipids, impaired vasculature function, decreased fatty add oxidation during fasting, and reduced postprandial glucose metabolism. Impairments in metabolic flexibility are linked to physical inactivity, excess energy intake and obesity, and genetic predisposition. Each of these factors precludes the development of insulin resistance and the cardiometabolic syndrome by mechanistic links that are not fully understood.
Polycystic Ovarian Syndrome
Authors: Khan Khurshid A. , Stas Sameer , Kurukulasuriya L. Romayne
Published: February 2007

Polycystic ovarian syndrome (PCOS) is the most common reproductive endocrinopathy of women during their childbearing years. A significant degree of controversy exists regarding the etiology of this syndrome, but there is a growing consensus that the key features include insulin resistance, androgen excess, and abnormal gonadotropin dynamics. Familial and genetic factors cause predisposition to PCOS. Insulin resistance and adiposity put women with PCOS at a higher risk for diabetes, hypertension, dyslipidemia, and cardiovascular disease. Even though the adverse health consequences associated with PCOS are substantial, most women are not aware of these risks. Early recognition and treatment of metabolic sequelae should be the main focus of clinicians. Lifestyle modifications, mainly a balanced diet, weight loss, and regular exercise, are of utmost importance. On the pharmacologic front, various therapies including metformin, thiazolidinediones, and others appear to be very promising in the management of cardiometabolic aspects of PCOS.
Effect of Short‐Term Pritikin Diet Therapy on the Metabolic Syndrome
Authors: Sullivan Shelby , Samuel Samuel
Published: February 2007

The Pritikin Program (Aventura, FL) involves the use of a very‐low‐fat, low‐sodium, high‐fiber diet and exercise to decrease the risk of coronary heart disease (CHD). This study evaluated the effect of short‐term Pritikin therapy on the metabolic risk factors for CHD in patients with the metabolic syndrome. Sixty‐seven subjects who had the metabolic syndrome and attended the Pritikin Longevity Center & Spa for 12–15 days were studied. Short‐term Pritikin therapy improved most CHD risk factors: body mass index decreased by 3% (P<.001); systolic and diastolic blood pressure, and serum glucose and low‐density lipoprotein cholesterol concentrations decreased by 10%–15% (P<.001); serum triglyceride concentration decreased by 36% (P<.001); and 37% of subjects no longer met National Cholesterol Education Program criteria for the metabolic syndrome. Serum high‐density lipoprotein cholesterol, however, decreased by 3% (P<.05). These data demonstrate that brief treatment with a very‐low‐fat, low‐sodium, high‐fiber diet and regular exercise simultaneously improves multiple CHD risk factors in patients with the metabolic syndrome.
The N‐terminus Domain of the a2 Isoform of Vacuolar ATPase Can Regulate Interleukin‐1β Production from Mononuclear Cells in Co‐culture with JEG‐3 Choriocarcinoma Cells
Authors: Ntrivalas Evangelos , Gilman‐Sachs Alice , Kwak‐Kim Joanne , Beaman Kenneth
Published: February 2007

Problem

a2V‐ATPase is the a2 isoform of vacuolar ATPase and is expressed in human trophoblast cells. a2V‐ATPase resides as a 70‐kDa molecule in intracellular vesicles. Upon cell stimulation, it migrates to the surface as a 50‐kDa molecule, after a 20‐kDa portion [N‐terminus domain of the a2V‐ATPase (a2NTD)] is cleaved and secreted to the extracellular environment. Previous studies showed that a2NTD‐regulated cytokine production from stimulated T cells. The aim of this study was to determine if a2NTD can regulate cytokine production from immune cells that were in contact with JEG‐3 cells.

Method of study

Peripheral blood mononuclear cells (PBMC) from females were co‐cultured with JEG‐3 cells in the presence or absence of a2NTD, and supernatants were analyzed by enzyme‐linked immunosorbent assay for interleukin (IL)‐1β. Additionally, PBMC cultured with JEG‐3 cells, in the presence or absence of a2NTD, were analyzed for cytokine gene expression by gene arrays.

Results

There was an increased secretion of IL‐1β and a decrease in type I and II IL‐1 receptors (IL1RA and IL‐1R2) gene expression in PBMC that were co‐cultured with JEG‐3 cells in the presence of a2NTD.

Conclusion

These data suggest a role for a2NTD in the regulation of IL‐1β pro‐inflammatory cytokine production at the fetal–maternal interface.
Introduction: Three Papers from The Texas A&M John Donne Collection: A Symposium and Exhibition
Authors: Stringer Gary A.
Published: February 2007

This paper introduces a Literature Compass panel cluster arising from the The Texas A&M John Donne Collection: A Symposium and Exhibition. Comprising an introduction by Gary Stringer and three of the papers presented at the symposium, this cluster seeks to examine the current state of Donne Studies and aims to provide a snapshot of the field. The symposium was held April 6–7, 2006.

The cluster is made up of the following articles:

‘Introduction: Three Papers from The Texas A&M John Donne Collection: A Symposium and Exhibition,’ Gary A. Stringer, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00420.x.

‘Donne and Disbelief: The Early Prose,’ Ernest W. Sullivan, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00421.x.

‘The Cultural Significance of Donne's Sermons,’ Jeanne Shami, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00422.x.

‘T. R. O’Flahertie's Copy of Donne's Letters,’ Donald R. Dickson, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00423.x.
Donne and Disbelief: The Early Prose
Authors: Sullivan Ernest W.
Published: February 2007

This paper is part of a Literature Compass panel cluster arising from the The Texas A&M John Donne Collection: A Symposium and Exhibition. Comprising an introduction by Gary Stringer and three of the papers presented at the symposium, this cluster seeks to examine the current state of Donne Studies and aims to provide a snapshot of the field. The symposium was held April 6–7, 2006.

The cluster is made up of the following articles:

“Introduction: Three Papers from The Texas A&M John Donne Collection: A Symposium and Exhibition,” Gary A. Stringer, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00420.x.

“Donne and Disbelief: The Early Prose,” Ernest W. Sullivan, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00421.x.

“The Cultural Significance of Donne's Sermons,” Jeanne Shami, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00422.x.

“T. R. O’Flahertie's Copy of Donne's Letters,” Donald R. Dickson, Literature Compass 4 (2007), 10.1111/j.1741‐4113.2007.00423.x.

Unlike his ancester, Sir Thomas More, who attempted to control audience response to his printed Utopia by encoding paradoxical and ambiguous elements into his text, John Donne attempted to control his audience and its response to his Paradoxes and Problems as well as his Biathanatos by restricting their manuscript circulation and by using “metacommentary” in the form of letters to his readers calling attention to the paradoxical qualities of these works. When the Paradoxes and Problems as well as Biathanatos were printed after Donne's death, however, his now unrestricted audience no longer had access to his personal letters of metacommentary, resulting in substantial confusion and ambiguity regarding Donne's intended messages.
The site‐specific epidemiology of hip fracture in the Australian Capital Territory with projections for the first half of the 21st century: Implications for clinical management and health services planning
Authors: Fisher AA , Davis MW , Rubenach SE , Le Couteur DG , McLean AJ
Published: February 2007

Objectives: To analyse the site‐specific epidemiology of hip fracture (HF) for the ACT and to project HF up to 2051.

Methods: Age‐ and sex‐specific rates of HF and projections of the number of HFs were calculated by applying the age‐ and sex‐specific rates to the median population projections.

Results: Analysis of patterns of HF by anatomical site of fracture revealed a diverse relationship according to age and sex. Fracture rates were higher in men before age 60 (1.8 : 1), and thereafter in women (3.1 : 1). In the age group of 60–64 years, the female : male ratio was 8.2 : 1 for cervical versus 1.8 : 1 for trochanteric fractures. Treatment for osteoporosis was under‐utilised. HF in people aged > 60 years will almost double by 2011, and increase 2.5‐fold and 5.4‐fold by the years 2021 and 2051, respectively. The greatest increase will occur in older men.

Conclusions: The number of HFs in the first half of the 21st century will increase dramatically. Aetiological and pathophysiological differences in HF emphasise the need to individualise preventative strategies.
A Support Group Intervention for Children Bereaved by Parental Suicide
Authors: Mitchell Ann M. , Wesner Sue , Garand Linda , Gale Deborah Dysart , Havill Allyson , Brownson Lynn
Published: February 2007

TOPIC:  Bereavement is considered by many to be among the most stressful of life events, and it becomes particularly distressing when it concerns the suicide death of a parent. Such an event is especially traumatic for children.

PURPOSE AND SOURCES:  The purpose of this paper is to present a case for support group interventions designed specifically for child survivors of parental suicide. The authors provide a theoretical framework for supportive group interventions with these children and describe the structure of an 8‐week bereavement support group for this special population of suicide survivors.

CONCLUSIONS:  A case is made for designing and implementing group interventions to meet the mental health needs of this important group of individuals.
Fabrication of high-resolution multiwall carbon nanotube field-emission cathodes at room temperature
Authors: Peng Yitian , Hu Yuanzhong , Wang Hui
Published: February 2007

Patterned films of multiwall carbon nanotubes (MWCNTs) were fabricated by the “wet” deposition of MWCNT dispersion on a patterned substrate. Films in the form of stripes or lattices of micrometer dimensions and variable thickness were obtained. The films were uniform and adhered strongly to the substrates. Field-emission property of the MWCNT film was investigated. The method can be used at room temperature for the assembly and integration of MWCNTs in the fabrication of nanodevices, including field-emission displays.
Surface treatments of SiGe for scanning tunneling microscopy/spectroscopy and characterization of SiGe p-n junction
Authors: Okui Toshiko , Tanaka Yuma , Shiraki Yasuhiro
Published: February 2007

Hydrogen-termination of SiGe(001) surfaces for scanning tunneling microscopy/spectroscopy (STM/STS) measurements was realized by optimizing the chemical treatment. It was found that the chemical oxidation with H2SO4 made the SiO2∕SiGe interface smooth and that the resultant hydrogen-terminated surface treated in the HF+HCl solution had few surface states in the band gap. This surface enabled the authors to evaluate the electrical properties of SiGe by STM/STS. Using the chemical method developed here, STM images of SiGe p-n junctions clearly visualized the existence of the depletion region. Furthermore, the distribution of the local electric properties of SiGe p-n junctions could be revealed with the spatial resolution better than 5×5nm2. It is concluded that STM/STS is a powerful technique to evaluate the local properties of Si∕SiGe devices.
Fringe field theory and experiment for electrostatic chucking of extreme ultraviolet photomasks
Authors: Raghunathan S. , Govindaraju L. , Ruan J. , Hartley J. G.
Published: February 2007

Fringe fields during electrostatic chucking depend on a variety of factors including the type and design of the chuck, chucking voltage, the proximity of other hardware and the electrical characteristics of the mask. The effects of uniform target potentials on the degradation of the position and imaging of an electron beam from a mask writer has been reported previously [J. Ruan and J. G. Hartley, Proc. SPIE 5992, 1385 (2005)]. In this article the authors are reporting on our modeling and experimental studies of the asymmetrical field environment induced by the fringe fields from electrostatic chucks. It has been proposed that masks for extreme ultraviolet (EUV) lithography be patterned in an electron beam mask writer equipped with the same style of chuck that will hold the mask in the exposure tool. Modeling of the fringe fields was performed using Munro’s electron beam software (MEBS SW Ltd., 14 Cornwall Eardens, London SW7 4AN, England) (MEBS) and an experimental apparatus was constructed which enabled a direct measurement of the axial electric potential for various styles of EUV masks and chucks in simulated electron beam writer environments. This article examines the fringing fields due to electrostatic chucking of EUV masks on two different chucks and three electron optic column designs as well as masks with a continuous conductive coating and ones with electrical isolation between the top and bottom sides. Specific recommendations are made for an optimal mask patterning strategy when using electrostatic chucks to hold the mask.
Influence of starting material on analog technology fabrication yield and device component performance
Authors: Mahalingam Pushpa , Wu Xiaoju , Knerr Ron , Patton Yvonne , Khan Imran
Published: February 2007

Choice of substrate used for analog complementary metal-oxide-semiconductor (CMOS) technologies impacts device performance and fabrication yields significantly. This study examines the impact of low-angle (<5°) off-axis Si(100) substrate rotated around ⟨110⟩ axis and 0° Si(100) on-axis starting material on inline process control, parametric device performance, and ultimately fabrication yields. The interaction of thermal processes and silicon epitaxial growth process variation on inline photoalignment and its influence on device design and performance is discussed for both types of substrates. The device components include 3 and 5V analog CMOS, lateral p-n-p bipolar transistor, junction field effect transistors, and drain extended transistors, DENMOS and DEPMOS, where the drain extensions are formed using well implants. The necessity to reintegrate silicon epitaxial growth, well photolithography and implants, Vt implants, and gate oxide process loop to accommodate substrate crystal orientation changes will be presented. A novel front-end-of-the-line integration scheme to improve interwafer and intrawafer electrical distributions with excellent transistor matching and 1∕f noise performance for aforementioned device components will also be discussed in this context.
Interface chemical characterization of novel W∕HfO2∕GeON∕Ge stacks
Authors: Martinez E. , Renault O. , Clavelier L. , Le Royer C. , Hartmann J.-M. , Loup V. , Minoret S. , Cosnier V. , Campidelli Y. , Zegenhagen J. , Lee T.-L.
Published: February 2007

The downscaling of complementary metal-oxide semiconductor transistors requires new materials such as Ge substrates for high carrier mobility and high-k dielectrics to decrease the equivalent oxide thickness while reducing the leakage current from the channel to the gate. Photoemission and Auger electron spectroscopies are used to investigate the interfaces of the W∕HfO2∕GeON∕Ge stack. Hard x-ray photoemission spectroscopy is also used to achieve bulk sensitivity. The GeON thin interfacial layer is obtained by nitridation of the germanium native oxide. Nitridation at 480°C and 120mbars yields the highest nitrogen incorporation (nearly 20at.%). X-ray photoemission spectroscopy analysis shows the presence of Ge–Hf bonding states, indicating direct interaction between the germanium and the hafnium oxide despite the GeON passivating layer. High energy photoemission is used to probe the buried W∕HfO2 interface. No interfacial layer such as WOx is observed between W and HfO2.
Low temperature ZEP-520A development process for enhanced critical dimension realization in reactive ion etch etched polysilicon
Authors: Wang H. , Laws G. M. , Milicic S. , Boland P. , Handugan A. , Pratt M. , Eschrich T. , Myhajlenko S. , Allgair J. A. , Bunday B.
Published: February 2007

The authors report on the realization of an enhanced process protocol for producing sub-20nm wide lines with extremely narrow pitches in electron beam resist using a low temperature development process. Linewidths ranging from 10to50nm with a pitch range of 40–250nm have been fabricated on 8in. silicon wafers, using a JEOL JBX 6000 FS/E electron beam lithography tool at 50kV accelerating voltage. ZEP-520A (Nippon Zeon) resist, a nonchemically amplified positive electron beam resist was employed for this effort due to its dry-etch resistance and high-resolution characteristics. The development of the ZEP-520A resist in ZED-N50 developer (Nippon Zeon) has been characterized and optimized for both low and room temperature developer conditions. In addition, standard reactive ion etch technologies have been utilized in conjunction with the low temperature developed ZEP-520A patterns to produce 10nm range gratings in polysilicon substrates with aspect ratios of 10:1. These gratings are intended for evaluation by angle-dependent and wavelength-dependent optical scatterometry methods for critical dimension measurements. The authors report on the preliminary etch optimization as well as advanced inductively coupled plasma etch characteristics of the pattern transfer.
Effects of corona discharge ions on the synthesis of silver nanoparticles by a supersonic nozzle expansion method
Authors: Jung Jae Hee , Park Hyung Ho , Kim Sang Soo
Published: February 2007

The synthesis of silver nanoparticles by a supersonic nozzle expansion method with corona discharge ions was investigated. For supplying ions in the developed nanoparticles generator, a corona discharger was used as an ionizer. Corona discharge ions function as nuclei for heterogeneous nucleation in the silver nanoparticle formation process and provide silver nanoparticles with a repulsive electrical force that prevents aggregation of the particles. For detailed analysis of such properties of synthesized nanoparticles as size, morphology, composition, and charge, sampled nanoparticles were investigated by means of transmission electron microscopy, x-ray diffraction analysis, energy-dispersive spectroscopy, and Faraday cup current measurement. Upon application of the corona discharge ions, the mean diameter of the synthesized nanoparticles was found to decrease. Further, charged and nonagglomerated silver nanoparticles can be synthesized.
Study of plasma-induced damage of porous ultralow-k dielectric films during photoresist stripping
Authors: Xu Songlin , Qin Ce , Diao Li , Gilbert Dave , Hou Li , Wiesnoski Allan , Busch Eric , McGowan Ricky , White Brian , Weber Frank
Published: February 2007

Plasma damage of low-k dielectrics during photoresist (PR) stripping in a dual-damascene process is a critical issue in the application of copper/low-k technology for ⩽45nm nodes to increase the signal processing speed of integrated circuit devices. In this article, a detailed and systematic work has been conducted to study the low-k damage on porous methyl silsesquioxane ultralow-k films using various PR strip chemistries and process conditions on a high density plasma reactor. The experimental results obtained from different test methodologies show that the low-k damage generated under fixed process conditions increases in the order of NH3<N2<H2∕N2<H2<O2. Among plasma control parameters, bias power has a very pronounced effect on low-k damage for reducing chemistries due to the acceleration of Si–C bond breaking by ion bombardment. Source power also affects the low-k damage significantly as it controls the ion density and flux to the wafer surface. The pressure effect is more complicated and shows different characteristics for oxidizing and reducing chemistries. The extent of low-k damage depends on the orientation of the wafer surface exposed to the plasma, leading to different sensitivity of the damage to the strip chemistry and process condition. Based on this work, an optimized chemistry and process regime are identified to effectively reduce low-k damage and achieve good strip process performance.
Negative resist behavior of neutral sodium atoms deposited on self-assembled monolayers
Authors: Ju Sanghyun , Mills A. K. , Hang Qingling , Elliott D. S. , Janes D. B.
Published: February 2007

The authors report their initial studies of the negative resist behavior of neutral sodium atoms deposited on alkanethiol molecules during neutral atom lithographic processing. Their results show that neutral sodium atoms incident upon octadecanethiol, the longest molecule of the various alkanethiols among alkanethiol self-assembled monolayers (SAMs), formed the most robust negative resist during the patterning process and made high quality patterning profile. In order to interpret the nature of the surface interaction between neutral sodium atoms and SAMs, they examine the surface components using x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and rinse tests. Their results indicate that sodium neutral atoms do not chemically react with or physically damage the SAMs but rather accumulate on and possibly diffuse into the SAMs.
Self-aligned microtriode for plasma generation at atmospheric pressure
Authors: Han S. H. , Kim Y. M.
Published: February 2007

The authors report a monolithically fabricated triode for microplasma generation at atmospheric pressure. The microstructure is fabricated using a self-aligned electroplating process and a stable glow discharge is generated at atmospheric pressure. The generated plasma can be expanded by applying a lateral electric field using an integrated secondary cathode. I-V characteristics of the microtriode were measured in the glow discharge mode and indicated significant amounts of the ionized gas atoms were drifted to the secondary cathode, demonstrating its ability to enlarge the volume of the plasma.
Orogenic movement mechanism for the formation of symmetrical relief features in copper nitride thin films
Authors: Ji A. L. , Du Y. , Li C. R. , Wang Y. Q. , Cao Z. X.
Published: February 2007

Nonequilibrium growth of crystals has revealed an astonishing variety of structures, resulting from the interplay of relevant factors such as atomic mobility, thermal effect, dynamic heterogeneity, etc. In preparing thin films of the thermally unstable copper nitride Cu3N, growth proceeds with simultaneous nitrogen reemission, which both bestows a preferred, Cu-terminated {111} facet on the Cu3N crystallites and limits their size to about 45nm. The authors observed an orogenic movement of Cu3N nanocrystals via glide along the {111} planes, resulting in a hollow, relief morphology primarily of round caps and later of mesoscale rosettes which often demonstrate a fivefold symmetry at the center. The area expansion in the thin film by a few percent is sustained through the rearrangement of nanocrystals into ragged steps and terraces, while the ongoing fast growth prevents the relief features from cracking. The results bear broad significance for the film growth of thermally unstable materials.
Stability analysis and charts for slopes susceptible to translational failure
Authors: Eid Hisham T , Elleboudy Azza M , Elmarsafawi Hazem G , Salama Amani G
Published: February 2007

The aim of this paper is to develop two- and three-dimensional stability charts for slopes susceptible to translational failure. An extensive parametric study was conducted using a slope model that is designed to simulate field conditions with respect to configurations of the sliding mass, and unit weight and shear strength of the involved materials. Slopes subjected to different conditions of pore-water pressures and seismic forces were considered in the study. The study shows the special importance and difficulties of considering the end effects in the analysis of translational slope failures and suggests a method for quantifying and incorporating them. Charts presented in this paper do not require an iterative procedure in determining factor of safety. They give the practicing geotechnical engineer a fast and reliable method to estimate the two and three-dimensional factors of safety for slopes susceptible to translational mode of failure and to back-calculate the mobilized shear strength of materials involved in slope failures following such mode. Numerical examples are given to illustrate different uses of these charts.Key words: slope stability analysis, translational failure, two-dimensional analysis, three-dimensional analysis, seismic forces.
MINIMAL COOPERATION IN SYMPORT/ANTIPORT TISSUE P SYSTEMS
Authors: ALHAZOV ARTIOM , ROGOZHIN YURII , VERLAN SERGEY
Published: February 2007

We investigate tissue P systems with symport/antiport with minimal cooperation, i.e., when only 2 objects may interact. We show that 2 cells are enough in order to generate all recursively enumerable sets of numbers. Moreover, constructed systems simulate register machines and have purely deterministic behavior. We also investigate systems with one cell and we show that they may generate only finite sets of numbers.
INSTABILITY IN SCALAR CHANNEL OF FERMION–ANTIFERMION SCATTERING AMPLITUDE IN MASSLESS QED3 AND ANOMALOUS DIMENSIONS OF COMPOSITE OPERATORS
Authors: MITRA INDRAJIT , RATABOLE RAGHUNATH , SHARATCHANDRA H. S.
Published: February 2007

Instability in the scalar channel of the fermion–antifermion scattering amplitude in massless QED3 for number of flavors less than the critical value 128/3π2 is demonstrated. The anomalous dimensions of gauge-invariant composite operators are determined to O(1/N). Exponentiation of the O(1/N) infrared logarithm is explicitly demonstrated by evaluating the contribution of the ladder diagrams.
MAXIMALLY SYMMETRIC MINIMAL UNIFICATION MODEL SO(32) WITH THREE FAMILIES IN TEN-DIMENSIONAL SPACETIME
Authors: WU YUE-LIANG
Published: February 2007

Based on a maximally symmetric minimal unification hypothesis and a quantum charge-dimension correspondence principle, it is demonstrated that each family of quarks and leptons belongs to the Majorana–Weyl spinor representation of 14 dimensions that relate to quantum spin-isospin-color charges. Families of quarks and leptons attribute to a spinor structure of extra six dimensions that relate to quantum family charges. Of particular, it is shown that ten dimensions relating to quantum spin-family charges form a motional ten-dimensional quantum spacetime with a generalized Lorentz symmetry SO (1, 9), and ten dimensions relating to quantum isospin-color charges become a motionless ten-dimensional quantum intrinsic space. Its corresponding 32-component fermions in the spinor representation possess a maximal gauge symmetry SO (32). As a consequence, a maximally symmetric minimal unification model SO (32) containing three families in ten-dimensional quantum spacetime is naturally obtained by choosing a suitable Majorana–Weyl spinor structure into which quarks and leptons are directly embedded. Both resulting symmetry and dimensions coincide with those of type I string and heterotic string SO (32) in string theory.
HEURISTIC DEVELOPMENT OF A DIRAC–GOLDHABER MODEL FOR LEPTON AND QUARK STRUCTURE
Authors: ROSEN GERALD
Published: February 2007

All three charged lepton pole masses are given to O(10-5) accuracy by [Formula: see text], where θk = 2πk/3 + 2/9 with the generation number k = 1, 2, 3. In the context of a Dirac model, it is shown that this empirical formula for the charged leptons admits a satisfactory S3-parametrized extension for the scale-independent pole masses of quarks and Majorana neutrinos; in particular, the top quark mass emerges as 177.698 GeV. A physical-geometrical interpretation of the mass formula supports Dirac's and Goldhaber's proposals: leptons and quarks of the same generation are identical in size and shape. Specifically, their self-interaction mass appears to be concentrated on spherical surfaces of radii [Formula: see text], in which the Kähler radial complex coordinate zk is a root of the Calabi–Yau condition [Formula: see text] for the envelopment of the particle surfaces and ℓ is a fundamental length constant.
An In Situ Ellipsometric Study of the Competitive Adsorption of PEG-/Cl-/(SPS/MPS)on Cu
Authors: Walker Marlon L. , Richter Lee , Moffat T.
Published: February 2007

The adsorption of Cu electrodeposition accelerating agents bis- (3-sodiumsulfopropyl disulfide) (SPS) and (3-mercaptopropyl) sulfonate (MPS) on evaporated Cu thin films was examined in- situ using spectroscopic ellipsometry under quiescent conditions. Both the thiol MPS and disulfide SPS resulted in definitive changes in the optical response of the interface, indicative of irreversible chemisorption. The optical responses of the two additives were different, however, suggesting a difference in the adsorbed states. Cl¯ can reversibly co-adsorb with either MPS or SPS. Pre-adsorption of either MPS or SPS inhibit the specific adsorption of polyethylene glycol (PEG) in the presence of Cl¯. Both SPS and MPS adsorption displace pre-adsorbed PEG layers. The kinetics of the PEG displacement reaction differ significantly between the thiol and disulfide, consistent with observations of their respective effect on metal deposition kinetics.
Silver Direct Electrodeposition on Ru Thin Film
Authors: Koo Hyo-Chol , Kim Jae Jeong , Kim Keeho
Published: February 2007

Ag electrodeposition was performed on Ru thin films following electrochemical reduction of native Ru oxide. Oxide reduction was critical for the formation of continuous Ag film, and large overpotential was important for high-density nucleation. Thermal stability of the Ag film was also improved with more negative applied potential.
Numerical and Experimental Investigation of Wet Chemical Etching of Silicon Wafers
Authors: Kaneko Kimihisa , Tamenori Akira , Alleborn Norbert , Durst Franz
Published: February 2007

Wet chemical etching is widely used in semiconductor production processes. The advantage lies in low investment costs and the absence of mechanical stress during etching. This method allows producing of extremely thin and flat wafers. However, etching is strongly influenced by hydrodynamics. To estimate the wafer surface profile after wet chemical etching, numerical simulations of fluid flow coupled with species transport using a simplified chemical reaction are carried out. It is shown that this approach can be applied with good accuracy to estimate etching rate for various operation conditions.