bluuebunny/crossref_metadata_2025 huggingface dataset:
Commodity Prices and the Terms of Trade
Authors: Bidarkota Prasad , Crucini Mario J.
Published: April 2004

On combining national terms‐of‐trade data for developing countries with world prices of internationally traded primary commodities, it is found that variation in the world prices of three or fewer key exported commodities account for 50% or more of the annual variation in the terms of trade of a typical developing country. A considerable fraction of the variation is specific to a particular commodity and, given that the overall importance of primary commodities differs across developing countries, it is possible to account for much of the heterogeneity across them. It is concluded that commodity price fluctuations should be central features of two related literatures: studies of business cycle transmission across developing and industrialized nations, and empirical work aimed at constructing perpetual claims on developing country incomes as suggested by Shiller in 1995.
Infection studies on human cell lines with porcine circovirus type 1 and porcine circovirus type 2
Authors: Hattermann Kim , Roedner Claudia , Schmitt Cornelia , Finsterbusch Tim , Steinfeldt Tobias , Mankertz Annette
Published: April 2004

Abstract:  Background:  The lack of human donor organs in allotransplantation has led to a proposal for the use of porcine tissues and organs as alternative therapeutic material for humans. Besides immunological problems like graft rejection, one of the major concerns is the transmission of porcine microorganisms as viruses, bacteria and fungi to a human recipient.

Methods:  Human cell lines have been infected with porcine circovirus type 1 (PCV1) and porcine circovirus type 2 (PCV2) to investigate whether PCV can infect and replicate in human epithelial cells and lymphocytes. Infection of PCV1 was observed with 293, Hela and Chang liver cells, infection with PCV2 only in Rd cells. In addition, religated viral DNA of PCV1 and PCV2 has been used to transfect adherent human cell lines.

Results:  PCV1 persisted in most cell lines without causing any visible changes, while PCV2‐transfected cells showed a cytopathogenic effect. Presence of PCV DNA was detected in cells and supernatant by PCR, expression of viral proteins by an indirect immune fluorescence assay. A replication assay showed that the replication of PCV DNA was initiated at the origin of replication. When virus‐free cells were inoculated with the supernatant of PCV‐infected human cells, the infection was not passed.

Conclusion:  Although PCV gene expression and replication took place in human cells, the infection is non‐productive. Alteration of protein localization suggests that protein targeting may be disturbed in human cells.
Magnesium‐induced vasodilation in the dorsal hand vein⋆
Authors: Landau Ruth , Scott Jason A. , Smiley Richard M.
Published: April 2004

Objective  Magnesium affects blood pressure by modulating vascular tone and reactivity. In obstetric patients, magnesium is administered to prevent eclamptic seizures and as a tocolytic to treat preterm labour. Prior to studying vascular sensitivity in women with pre‐eclampsia, we sought to determine the effect of magnesium on venous tone in healthy women of childbearing age.

Design  Dose–response study.

Setting  Columbia‐Presbyterian Medical Center, New York.

Population  Ten healthy non‐pregnant women (age range 21–47 years).

Methods  Vascular response to magnesium sulphate (MgSO4) was measured in a dorsal hand vein using the linear variable differential transformer (LVDT) technique. Complete dose–response curves to MgSO4 (0.0000275–0.088 mmol/min) were determined after 50% preconstriction of the vein with phenylephrine.

Main outcome measures  The ED50 of MgSO4 (dose resulting in 50% of maximal effect, Emax) was determined. Blood samples from the contralateral upper extremity were obtained to assess total plasma magnesium levels at baseline and at the highest infused dose of magnesium. ED50 results are expressed as geometric mean (95% confidence interval, CI). Emax results and magnesium plasma concentrations are expressed as mean [SD].

Results  The ED50 of MgSO4 was 0.000307 mmol/min (95% CI 0.138, 0.666) and Emax was 102% [20%].

Conclusion  Magnesium induces dose‐dependent venodilation in healthy women in the absence of systemic haemodynamic effects. The dose resulting in vasodilation using the LVDT/hand vein model is two to three orders of magnitude less than the therapeutic doses of magnesium used for tocolysis or seizure prophylaxis. Studies of the effect of systemically administered therapeutic doses of magnesium on vascular reactivity in pre‐eclampsia will be of interest.
Evidence for suboptimal use of periconceptional folic acid supplements globally
Authors: Ray Joel G. , Singh Gita , Burrows Robert F.
Published: April 2004

Objective  To systematically summarise the available evidence concerning the rate of folic acid supplement use pre‐ and periconceptionally, to identify those characteristics associated with low rates of use and to assess whether folic acid public awareness campaigns are associated with higher folic acid use.

Design  Systematic overview.

Setting  Survey studies.

Population  Women of reproductive age, most of whom were currently or recently pregnant.

Methods  Two investigators searched MEDLINE, Embase and Nutriotiongate databases between 1990 and 2003. Bibliographies of retrieved references were scanned for other relevant publications, and authors were contacted if necessary. Studies were included that evaluated the rate of folic acid supplement use either before conception or in early pregnancy.

Main outcome measures  Rate of preconceptional and/or periconceptional folic acid use, rate of planned pregnancy in each study, as well as significant characteristics differentiating non‐users from users of folic acid, including the effect of folic acid awareness campaigns.

Results  A total of 52 studies were included. In 34 studies, reported preconceptional folic acid use varied from 0.9% to 50%. In 49 studies, the reported rate of periconceptional supplement use ranged from 0.5% to 52%. Significant predictors of reduced periconceptional folic acid use were a low level of formal education, immigrant status, young maternal age, lack of a partner and an unplanned pregnancy. Four studies examined the effect of mass media campaigns on periconceptional folic acid use; the reported rates increased significantly, by a factor of 1.7 to 7.2, but in no study was the post‐campaign rate above 50%.

Conclusions  In many countries, fewer than 50% of women take periconceptional folic acid supplements. Consideration should be given to the practical advantages of folic acid fortification of centrally processed foods, such as wheat, corn and rice flour, while further promoting vitamin tablet supplement use and planned pregnancy.
The accuracy of various tests for bacterial vaginosis in predicting preterm birth: a systematic review
Authors: Honest Honest , Bachmann Lucas M. , Knox Ellen M. , Gupta Janesh K. , Kleijnen Jos , Khan Khalid S.
Published: April 2004

Objective  To determine the accuracy with which various types of tests for bacterial vaginosis predict spontaneous preterm birth in pregnant women.

Data sources  Studies were identified without language restrictions through nine different databases, and manual searching of bibliographies of known primary and review articles.

Study selection and data extraction  There are four different bacterial vaginosis testing methods: Gram staining tests using either Nugent's or Spiegel's criteria, and gas liquid chromatography are laboratory based, and the fourth method uses clinical (Amsel's) criteria to diagnose bacterial vaginosis. Two reviewers independently selected studies and extracted data on their characteristics, quality and accuracy. Accuracy data were used to form 2 × 2 contingency tables of the bacterial vaginosis test results with spontaneous preterm birth as the reference standard.

Data synthesis  Data on asymptomatic women and women with symptoms of threatened preterm labour were analysed separately. Data were pooled to produce summary estimates of likelihood ratios for positive (LR+) and negative (LR−) test results for the various types of tests.

Results  There were 18 primary articles, involving altogether 17,868 women. There was unexplained heterogeneity in the meta‐analyses of the accuracy results, which requires caution in their interpretation. Meta‐analyses of studies testing asymptomatic women in the second trimester showed that clinical criteria had a LR+ of 0.98 (95% confidence interval 0.59 to 1.6) and a LR− of 1.00 (0.93 to 1.1), Gram staining (Nugent's criteria) had a LR+ of 1.6 (1.4 to 1.9) and a LR− of 0.9 (0.8 to 0.9), and Gram staining (Spiegel's criteria) had a LR+ of 2.4 (1.4 to 4.9) and a LR− of 0.81 (0.64 to 1.0). Among symptomatic women, Gram staining (Spiegel's criteria) had a LR+ of 1.3 (1.0 to 1.6) and LR− of 0.9 (0.7 to 1.0).

Conclusion  There was a lack of difference in the accuracy of the various bacterial vaginosis tests for predicting preterm birth in both asymptomatic and symptomatic women of threatened preterm labour.
The Benefits of Exercise for Individuals with Arthritis: An Integrative Review with Meta‐Analysis
Authors: Rogers Sharon
Published: April 2004

(1) While individuals with osteoarthritis (OA) and rheumatoid arthritis (RA) are frequently seen by caregivers in the health care system, some confusion still exists when it comes to making recommendations related to exercise and activity. While a number of research studies have supported the safety and benefits of moderate to rather intense exercise for both of these conditions, many practitioners continue to recommend limited activity for these populations. This review of the research literature and meta‐analysis seeks to explicate for the practitioner the “state‐of‐the‐art” in making exercise and activity recommendations to their clients with OA and RA.
The Effects of Saline Instillation Prior to Endotracheal Suctioning
Authors: Briening Eileen P.
Published: April 2004

(1) Instillation of a bolus of saline down the endotracheal or tracheostomy tube prior to suction is common nursing practice. The rationale is that saline will thin tenacious secretions and assist in removal of them. This article reviews the research related to the effects of saline instillation and the controversies about its use. Recommendations for practice and future research are made.
Agreement of Patients' and Nurses' Perceptions of Burn Pain: A Research Review
Authors: Calvin Amy O.
Published: April 2004

(1) The purpose of this study was to review all available research studies that reported the level of agreement between patients' and nurses' perceptions of burn pain. Findings from the eight studies included in this review varied, however, overall nurses appeared to be inclined to overestimate or underestimate patients' burn pain rather than rate patients' pain in accordance with patients' ratings. Possible factors that may have influenced the discrepancies in patients' and nurses' burn pain ratings and critiques of the eight research reports are discussed. Practice implications and recommendations for future research are provided.
An Integrative Review of Substance Abuse Among Nurses from 1981‐1997
Authors: Smardon Marguerite
Published: April 2004

(1) The body of literature suggests that the prevalence of substance abuse among nurses and nursing students is less than or similar to the general population, but that younger nurses may be more at risk. Male nurses may be at increased risk for substance abuse. Prevalence of substance abuse by clinical specialty remains unclear. Several risk factors for impairment including depression and lack of social support were identified in the descriptive and qualitative studies. Perceptions and attitudes toward impaired nurses and colleagues reveal a lack of optimism about treatment by nursing management. Acceptance of the illness concept varied by ethnicity. Impaired nurses did not feel supported by nursing management. Peer assistance groups may be an effective means of addressing substance abuse among nurses.
Flushing Protocols for Tunneled Central Venous Catheters: An Integrative Review of the Literature
Authors: Buswell Lori , Beyea Suzanne C.
Published: April 2004

(1) The flushing regimes for and associated practices related to tunneled central venous catheters (Hickman and Broviac) vary widely. Recommendations for flushing tunneled central venous catheters are abundant in the literature, but few are research‐based. This manuscript describes the clinical problem and summarizes six research‐based studies that appear in the literature. Practice recommendations based on this review include using 5 mL of 10 unit/mL of heparin once or twice weekly. It is clear that additional prospective randomized studies are needed to elucidate the optimal flushing regime for patients with tunneled central venous catheters.
Incongruent Hierarchies: Daughters and Younger Sons as Company CEOs
Authors: Barnes Louis B.
Published: April 2004

The daughter or younger son who becomes head of the family business must struggle with both self-identity and changing family role expectations. How do they do this?

Father CEO: My oldest son is the nicest guy in the world and expects to become president of the company. But, my second son would be better. I also have a younger daughter in the business. I don't know what to do. I've told the kids they may have to decide.

Daughter CEO: From the time I became president eleven years after I joined the company, I was competing with my father—not from my side but from his side. Then the family struggle really started, particularly when my older brother wanted to join the business.

Younger brother CEO: I can't replace him, because he's my older brother, and I have to think my way out of it, or we may have a confrontation.
Family Firm and Community Culture
Authors: Astrachan Joseph H.
Published: April 2004

When a family firm is acquired, how will its culture and performance be affected by the culture of the new parent company?
Understanding of Father-Daughter and Father-Son Dyads in Family-Owned Businesses
Authors: Dumas Colette
Published: April 2004

This article compares the results of an empirical study of the father-daughter dyad in family-owned businesses with the literature on the father-son dyad in family-owned businesses, stresses the similarities and differences between these two dyads, and presents some implications for practice and research.
Family Farmers' Reactions to Their Work: A Job Diagnostic Survey
Authors: Hinsz Verlin B. , Nelson Leissa C.
Published: April 2004

Responses of family farmers to the Job Diagnostic Survey were examined to assess the internal rewards farmers receive from their work. It is suggested that family farmers' high motivation and commitment to farming are largely influenced by the positive job characteristics associated with farming.
at Interview with Craig E. Aronoff, Founder of the Kennesaw State College Family Business Forum
Authors: Astrachan Joseph H.
Published: April 2004

Craig E. Aronoff shares his experiences in setting up and managing the Family Business Forum, an innovative institution devoted to educating family business members about family business issues. It achieves this through a regular schedule of presentations by national experts, presentations by sponsor organizations, newsletters, and through promoting interaction and informal learning among members.
Preparing the New CEO: Managing the Father-Daughter Succession Process in Family Businesses
Authors: Dumas Colette A.
Published: April 2004

The personality of the CEO has a profound impact on the structure, culture, and strategy of small- and medium-sized firms, and the relationship between CEO-father and successor-daughter is a key element in the development of the daughter's personality.
Location Preferences of Family Firms: Strategic Decision Making or “Home Sweet Home”?
Authors: Kahn Joel A. , Henderson Douglas A.
Published: April 2004

Selecting a business location is among the most important strategic decisions for family firms. Yet the separate demands of the family and the business often prove difficult to balance. A comparison of location preferences in family and nonfamily firms provides insight into the family influence on strategic decision making.
Theoretical Foundations for Family-Owned Business: A Conceptual and Research-Based Paradigm
Authors: Wortman Max S.
Published: April 2004

As a field of study, family-owned business has lacked a coherent comprehensive framework. Currently the field is based largely on the succession literature, where the number of conceptual and empirical studies has doubled in the past five years. By using a conceptual and research-based typology for the field, the conceptual and empirical studies can be evaluated. Based upon the typology, potential studies and questions have been suggested for future research.
Healthy Family Functioning: Conceptual and Research Developments
Authors: Walsh Froma
Published: April 2004

An important development in family process research has been the redirection from a family deficit focus to a normality based orientation. This approach seeks to identify the family strengths and resources that are crucial in mastering life challenges and promoting the well-being and healthy development of individual family members. Drawing on conceptual and research contributions from the field of family therapy and the social sciences, this article presents recent developments in our understanding of normal family processes and the patterns that distinguish well-functioning families from dysfunctional ones. Emerging research findings are synthesized in an integrative framework that specifies key components of family functioning in three domains: organizational patterns, communication processes, and multigenerational life cycle patterns and belief systems.
Farm Women as Full-Time Partners: Some Evidence of Sharing Traditional Gender-Based Tasks
Authors: Rappaport Allen
Published: April 2004

The farm and home decision and task responsibilities of husbands and wives for two groups are examined: (1) five hundred ninety-two married male respondents who are husbands in traditional farm families including those with children under twenty-one and wives who work off the farm; and (2) forty married male respondents who consider their wives full-time partners, who indicate that their wives work equally hard on the farm, have no children under twenty-one at home, and do not have off-the-farm employment. For the 592-respondent group, the traditional gender-based division of farm and home decisions and tasks applied. For the full-time partners group, men continued to perform the traditional farm tasks, while wives shared to a greater extent in but did not have sole responsibility for farm decisions or tasks. The forty male respondents reported crossing over and sharing domestic tasks.
Myths and Realities: Family Businesses' Contribution to the US Economy— A Framework for Assessing Family Business Statistics
Authors: Shanker Melissa Carey , Astrachan Joseph H.
Published: April 2004

This article presents a framework for assessing commonly accepted family business statistics, based on the criteria used to define a family business. Using existing research from multiple fields and sources, a range is extrapolated for the total number of family businesses in the US, their contribution to Gross Domestic Product (GDP) and employment.
Load/Unload Systems With Multiple Flying Height States
Authors: Suk M. , Ruiz O. , Gillis D.
Published: April 2004

In hard disk drives that utilize load/unload technology, the slider loads onto the disk from hundreds of microns away before the slider settles into the designed flying height. Due to the forces acting on the slider after the transition from the unloaded state to the fully loaded state, the resulting flying height of the slider may be about two orders of magnitude higher than the intended nominal flying height. Under certain circumstances, the slider may never reach the nominal flying height required for proper operation of the magnetic recording process. In this paper, the existence of multiple flying heights is demonstrated and verified both by experimentation and simulation. The effect of some of the critical parameters is also identified by both methods. We show that necessary care must be taken to avoid unwanted loading sequences where the system may be unable to store or retrieve data.
A Bulk-Flow Analysis of Static and Dynamic Characteristics of Eccentric Circumferentially-Grooved Liquid Annular Seals
Authors: Arghir Mihai , Frene Jean
Published: April 2004

The bulk-flow equations used for inertia dominated thin-film flows is an attractive model for the analysis of circumferentially grooved annular seals because the solutions based on the numerical integration of the complete Navier-Stokes equations can be very time-consuming. By using three types of control volumes and some user-tuned constants, the bulk-flow model can be used for calculating the static and the dynamic characteristics. Until now, this has been carried out for centered seals where the flow is governed by ordinary differential equations but no solutions have yet been given for eccentric working conditions. In this latter case, the model is governed by partial differential equations of an elliptic type. The main problem is that for describing the groove effects, the pressure field must incorporate the concentrated drop or recovery effects that occur at the interface between the groove and the land zone. This means that the numerical procedure used for solving the elliptic equations should be able to handle a pressure field having discontinuous values and discontinuous first order derivatives. In the present work, the method used for integrating the system of bulk-flow equations is the SIMPLE algorithm. The algorithm is extended for handling pressure jumps by adding two pressure values on each side of the discontinuity. These values are then expressed in terms of cell centered pressures by imposing the mass conservation and the generalized Bernoulli equation at the discontinuity. This numerical solution is original and has never previously been presented in the finite volume related literature. Comparisons between the numerical predictions (leakage flow rate and rotordynamic coefficients) and experimental data taken from the literature Marquette and Childs (1997) are subsequently presented for an eccentric ten-groove annular seal.
Topology Designs of Slider Air Bearings
Authors: Yoon Sang-Joon , Choi Dong-Hoon
Published: April 2004

A new approach for topology designs of slider air bearings in magnetic recording disk drives is suggested by using large-scale discrete variable optimization techniques. Conventional optimization techniques are restricted to the original topology of the slider by modifying the initial designs. To overcome the restriction, a new topology design approach is presented with enhanced mathematical techniques. Topology optimization of slider air bearings typically has a large number of design variables because the finite mesh must be fine enough to represent the shape of the air bearing surface (ABS). To handle a large number of design variables, an efficient strategy for the optimization including the sensitivity analysis must be established. As a gradient-based local optimization algorithm, the sequential unconstrained minimization technique (SUMT) using an exterior penalty function is used, which requires little computational effort and computer memory. For the gradient calculation, the analytical design sensitivity analysis method introducing an adjoint variable is employed. A topology design problem is formulated as a function of the residuals which is calculated by solving the generalized Reynolds equation. A very large number of discrete design variables (=9409) are dealt with, which denote the rail heights at grid cells. To validate the suggested design methodology, a developed program is applied to two slider models with one and three trailing rails. The simulation results demonstrated the effectiveness of the proposed design methodology by showing that the optimized topologies have reasonable shapes without any initial designs.
The calculation of radiated acoustic pressure fields from irregular multi-sided polygons
Authors: Neild Adrian , Hutchins David A.
Published: April 2004

This paper presents a method of calculating the pressure at any point emerging from a plane piston of polygonal shape in an infinite baffle. This is achieved by calculation of the impulse response as a time-stepped function, and considering the effect of each edge of the polygon in turn. The pressure is found from the convolution of this function with the time derivative of the piston velocity multiplied by the density of the propagation medium. Calculated pressure fields are shown for both a series of sources shaped as regular polygons, and for a source with an irregular shape. It is shown that the approach could be useful for the calculation of radiated fields from sources of arbitrary shape.
Tunneling effect in sound transmission loss determination: Theoretical approach
Authors: Kim Bong-Ki , Kang Hyun-Ju , Kim Jae-Seung , Kim Hyun-Sil , Kim Sang-Ryul
Published: April 2004

The aim of this study is to numerically evaluate a tunneling effect in the laboratory measurement of sound transmission loss. The tunneling effect arises from the depth of an aperture in the common wall between the source and receiving rooms. Variations of the sound transmission loss with the parameters of panel location, tunnel depth, and panel size are investigated. The difference in sound transmission loss is quite evident below the coincidence frequency and it greatly depends on the panel location in the tunnel. In comparison with the transmission loss of a finite plate in an infinite rigid baffle (with no tunnel) the maximum difference occurs in the laboratory measurement when the panel is placed at the center of the tunnel, while a better estimation of true transmission loss is obtained when the panel is located at either end. The results provide an added guideline for the standard laboratory test method for sound transmission loss.
An echo analysis technique for estimating the fish population
Authors: Kumar C. P. Anil , Pai Sajith N. , Soniraj N. , Supriya M. H. , Kurian James , Madhavan C. , Pillai P. R. Saseendran
Published: April 2004

The development of an algorithm for the estimation of biomass by acoustic remote sensing is presented in this paper. The distinctive features of the algorithm include the implementation of time-varied gain function, proper accounting of beam factor effects, implementation of backscattering levels for selected species and processing for echo-count as well as echo-integration. In order to optimize the backscattering levels, numerical analysis for geometrical backscattering of selected marine species were carried out and validated with in situ measurements. The biomass information of the concerned marine specie is made available by subjecting the backscattered raw data to a series of processes. The performance validation of the algorithm under in situ conditions yielded encouraging population estimation results and is being fine-tuned with the field data. This algorithm will provide an efficient technique to parametrically compute the target strength, leading to the estimation of the stock of commercially important selected marine species under varied environmental conditions in different regions.
QUANTUM RESOLUTION OF THE NONLINEAR SUPER-SCHRÖDINGER EQUATION
Authors: CAUDRELIER V. , RAGOUCY E.
Published: April 2004

We introduce a ℤ2-graded version of the nonlinear Schrödinger equation that includes one fermion and one boson at the same time. This equation is shown to possess a supersymmetry which proves to be itself part of a super-Yangian symmetry based on gl (1|1). The solution exhibits a super version form of the classical Rosales solution. Then, we second quantize these results, and give a Lax pair formulation (based on gl (2|1)) for the model.
OPTICAL SPECTROSCOPY AND NONLINEAR TRANSMITTANCE STUDY OF FULLERENE C60 IN MIXTURES WITH 2-CYCLOOCTYLAMINO-5-NITROPYRIDINE (COANP)
Authors: SARKISOV SERGEY S. , RADOVANOVA ELENA I. , PETERSON BURL H. , LEYDERMAN ALEX , CURLEY MICHAEL , FLEITZ PAUL A.
Published: April 2004

Characterization of the infrared absorption spectrum of the solutions of fullerene C 60 with 2-cyclooctylamino-5-nitropyridine additive has been performed with the focus on possible bonding with the amino-group of the additive. No occurrence of such bonding was found at normal conditions. Also no change of optical absorption in visible region and optical limiting of fullerene due to chemical bonding with the additive was detected. The resulting optical properties of the mixture were simply a sum of the properties of the components for a molar proportion of the additive to fullerene approaching 200:1.
OPTICAL AMPLITUDE AND PHASE EVOLUTION IN NONLINEAR MAGNETO-OPTICAL BRAGG GRATINGS
Authors: JONSSON FREDRIK , FLYTZANIS CHRISTOS
Published: April 2004

We present a theory on stratified nonlinear magneto-photonic crystals, with arbitrary spatial distribution of the refractive index and magneto-optical coefficients. The coupled mode theory is formulated for plane waves inside the crystal, and a perturbation series of integral solutions for the spectral response of the crystal is presented. Material issues and configurations are discussed, and the described theory is applied to the calculation of transmission spectra of binary magneto-photonic crystals.
Fabrication of Highly Ordered Anodic Porous Alumina Using Self-organized Polystyrene Particle Array
Authors: Masuda Hideki , Matsui Yoshitaka , Yotsuya Masato , Matsumoto Futoshi , Nishio Kazuyuki
Published: April 2004

Highly ordered anodic porous alumina was fabricated by anodization of vapor-deposited Al that had been deposited on a self-organized periodic array of polystyrene particles with a submicron-scale diameter on a glass plate. The ordered bumpy structure of the particle array surface was replicated on the deposited Al surface. Anodization was initiated at the concaves of the Al surface. Employment of the self-organized particle array to produce highly ordered anodic porous alumina with a submicron-scale channel structure was shown to be feasible.
Comments on “Regulation of the Rent-to-Own Industry: Implications of the Wisconsin Settlement with Rent-A-Center”
Authors: Winn Edward L.
Published: April 2004

This commentary offers an industry perspective on several of Hastak's (2004) premises pertaining to the future of the rent-to-own industry in Wisconsin. The commentary focuses on the legal characterization of rent-to-own transactions in Wisconsin as credit sales and practical issues that such a characterization pose for the industry. The commentary also offers an explanation of why Rent-A-Center adopted its new business format in the state.
Spatial and Orientational Templating of Semiconducting Polymers in a Cholesteric Liquid Crystal
Authors: Kang S.‐W. , Jin S.‐H. , Chien L.‐C. , Sprunt S.
Published: April 2004

A one‐dimensional pattern‐forming state of a cholesteric liquid crystal (CLC) is used as a template for the self‐organization of ordered, spatially orientated, acetylene‐based semiconducting polymers. The polymers are formed by metathesis reaction with all chemical components contained in an ordinary electro‐optic cell. The polymer morphology consists of parallel ∼ 1 μm thick bundles, uniformly spaced at ∼ 10 μm over the full macroscopic active area of the cell substrates. The polymer templating can be explained by a model that predicts a corrugation in polymer density determined by the spatially periodic profile of the orientational energy density associated with the pattern‐forming CLC state.
Synthesis of Nickel Sulfide Submicrometer‐Sized Hollow Spheres Using a γ‐Irradiation Route
Authors: Hu Y. , Chen J. F. , Chen W. M. , Li X. L.
Published: April 2004

Nickel sulfide (NiS) hollow spheres have been successfully synthesized by γ‐irradiation, at room temperature, of an aqueous PMMA–CS2–ethanol solution that contains NiSO4·6H2O. Electron microscopy results show that the diameter of the NiS hollow spheres and the thickness of the sphere shells are about 500 nm and 20 nm, respectively. The room‐temperature UV‐vis absorption spectrum of the NiS hollow spheres gives a peak centered at around 233 nm (5.56 eV) with a remarkable blue‐shift relative to that of bulk NiS (2.1 eV). This remarkable blue‐shift may be attributed to the small dimensions of the materials. A possible growth mechanism of NiS hollow spheres by γ‐irradiation method is also presented. The successful preparation of NiS hollow spheres on a large scale under mild conditions could be of interest for both applications and fundamental studies.
Robustness of Generalized Estimating Equation (GEE) Tests of Significance against Misspecification of the Error Structure Model
Authors: Overall John E. , Tonidandel Scott
Published: April 2004

Generalized linear model analyses of repeated measurements typically rely on simplifying mathematical models of the error covariance structure for testing the significance of differences in patterns of change across time. The robustness of the tests of significance depends, not only on the degree of agreement between the specified mathematical model and the actual population data structure, but also on the precision and robustness of the computational criteria for fitting the specified covariance structure to the data. Generalized estimating equation (GEE) solutions utilizing the robust empirical sandwich estimator for modeling of the error structure were compared with general linear mixed model (GLMM) solutions that utilized the commonly employed restricted maximum likelihood (REML) procedure. Under the conditions considered, the GEE and GLMM procedures were identical in assuming that the data are normally distributed and that the variance‐covariance structure of the data is the one specified by the user.

The question addressed in this article concerns relative sensitivity of tests of significance for treatment effects to varying degrees of misspecification of the error covariance structure model when fitted by the alternative procedures. Simulated data that were subjected to monte carlo evaluation of actual Type I error and power of tests of the equal slopes hypothesis conformed to assumptions of ordinary linear model ANOVA for repeated measures except for autoregressive covariance structures and missing data due to dropouts. The actual within‐groups correlation structures of the simulated repeated measurements ranged from AR(1) to compound symmetry in graded steps, whereas the GEE and GLMM formulations restricted the respective error structure models to be either AR(1), compound symmetry (CS), or unstructured (UN). The GEE‐based tests utilizing empirical sandwich estimator criteria were documented to be relatively insensitive to misspecification of the covariance structure models, whereas GLMM tests which relied on restricted maximum likelihood (REML) were highly sensitive to relatively modest misspecification of the error correlation structure even though normality, variance homogeneity, and linearity were not an issue in the simulated data.Goodness‐of‐fit statistics were of little utility in identifying cases in which relatively minor misspecification of the GLMM error structure model resulted in inadequate alpha protection for tests of the equal slopes hypothesis. Both GEE and GLMM formulations that relied on unstructured (UN) error model specification produced nonconservative results regardless of the actual correlation structure of the repeated measurements. A random coefficients model produced robust tests with competitive power across all conditions examined. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized Estimating Equations in Controlled Clinical Trials: Hypotheses Testing
Authors: Dahmen G. , Ziegler A.
Published: April 2004

Generalized estimating equations (GEE) for the analysis of clustered data have gained increasing popularity. Recently, the first monograph on this method has been published. GEE have been repeatedly applied in controlled clinical trials. They have, however, been generally used as secondary or supplementary analysis. Instead, the primary analysis was mostly based on a classical method that usually ignored the clustered – mostly longitudinal – nature of the data. In this paper, we discuss the applicability of GEE as primary analysis in controlled clinical trials. From theoretical results in the literature, we derive recommendations how GEE should be used in therapeutic studies for testing statistical hypotheses. We hope that our paper is the starting point for a thorough discussion on the most appropriate analysis of controlled clinical trials with clustered dependent variables. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ monitoring of cell death using Raman microspectroscopy
Authors: Verrier S. , Notingher I. , Polak J. M. , Hench L. L.
Published: April 2004

We investigated the use of Raman microspectroscopy to monitor the molecular changes in human lung carcinoma epithelial cells (A549) when cell death was induced by a toxic chemical. We treated A549 cells with 100 μM Triton X‐100 and carried out Raman microspectroscopy measurements in parallel with cell viability and DNA integrity assays at time points of 0, 24, 48, and 72 hours. We found that the important biochemical changes taking place during cell death, such as the degradation of proteins, DNA breakdown, and the formation of lipid vesicles, can be detected with Raman microspectroscopy. A decrease in the intensity of the O‐P‐O stretching Raman peak corresponding to the DNA molecule phosphate‐sugar backbone at 788 cm‐1 indicated DNA disintegration, an observation which was confirmed by DNA integrity analysis. We also found a decrease in the intensity of the Raman peaks corresponding to proteins (1005 cm‐1, 1342 cm‐1) and an increase in the concentration of lipids (1660 cm‐1, 1303 cm‐1). These changes are the effects of the complex molecular mechanisms during the induction of cell death, such as protein cleavage due to the activation of caspases, followed by DNA fragmentation. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Stereoscopic vision provides a significant advantage for precision robotic laparoscopy
Authors: Jourdan I C , Dutson E , Garcia A , Vleugels T , Leroy J , Mutter D , Marescaux J
Published: April 2004

Background

Current surgical robots provide no sense of touch and rely solely upon vision. This study evaluated the effect of new stereoscopic technology on the performance of robotic precision laparoscopy.

Methods

Eight experienced laparoscopists with no experience in robotics performed five tasks of increasing complexity using a laparoscopic robot. The tasks were as follows: rope pass, paper cut, needle capping, knot tying and needle threading. Each test was performed ten times under both stereoscopic and monoscopic conditions. Performance times and errors were recorded.

Results

Mean(s.e.m.) final performance times were calculated from the final five trial times for each test, and were as follows for monoscopic and stereoscopic conditions respectively: rope pass 112·8(4·2) and 97·0(3·7) s (P = 0·013), paper cut 117·1(6·0) and 98·4(9·8) s (P = 0·020), needle capping 144·5(12·7) and 99·7(6·8) s (P = 0·008), knot tying 138·7(14·3) and 70·3(6·0) s (P = 0·002), and needle threading 210·8(28·2) and 92·3(4·1) s (P = 0·002). The mean(s.e.m.) number of errors per candidate was 60·6(7·8) and 20·8(3·9) under monoscopic and stereoscopic conditions respectively (P = 0·004).

Conclusion

Stereoscopic vision provided a significant advantage during robotic laparoscopy in situations that required a precise understanding of structural orientation.
Endothelin axis expression is markedly different in the two main subtypes of renal cell carcinoma
Authors: Douglas Meaghan L. , Richardson Michelle M. , Nicol David L.
Published: April 2004

BACKGROUND

The endothelin axis has been implicated in cancer growth, angiogenesis, and metastasis, but to the authors' knowledge the expression of endothelin genes has not been defined in renal cell carcinoma (RCC).

METHODS

Tissue specimens were harvested from both normal and tumor‐affected regions at the time of radical nephrectomy from 35 patients with RCC (22 with clear cell RCC [ccRCC] and 13 with papillary RCC [PRCC]). Real‐time reverse transcriptase‐polymerase chain reaction analysis determined the expression profile of the preproendothelins (PPET‐1, PPET‐2, and PPET‐3), the endothelin receptors (ETA and ETB), and the endothelin‐converting enzymes (ECE‐1 and ECE‐2).

RESULTS

PPET‐1 was found to be up‐regulated in ccRCC tumor specimens and down‐regulated in PRCC tumor specimens. ETA was significantly down‐regulated in PRCC tumor specimens. ECE‐1 was expressed in all tissue specimens at comparable levels, with moderate but significant elevation in normal tissue specimens associated with PRCC. Of the other genes, PPET‐2 and ETB were expressed in all tissue specimens and no differences were observed between tumor subtypes or tumor‐affected and normal tissue specimens, whereas PPET‐3 and ECE‐2 were present in all tissue specimens but were barely detectable.

CONCLUSIONS

The endothelin axis was expressed differently in the two main subtypes of RCC and appeared to match macroscopic features commonly observed in these tumors (i.e., high expression of PPET‐1 in hypervascular ccRCC contrasted against low PPET‐1 and ETA expression in hypovascular PRCC). The presence of ECE‐1 mRNA in these tissue specimens suggested that active endothelin ligands were present, indicating endothelin axis activity was elevated in ccRCC compared with normal kidney, but impaired in PRCC. The current study provided further evidence that it is not appropriate to consider ccRCC and PRCC indiscriminately in regard to treatment. Cancer 2004. © 2004 American Cancer Society.
Mott‐hopping processes in neodymium oxide thin films prepared on Si(100) substrates
Authors: Dakhel A. A.
Published: April 2004

Thin Nd oxide films were prepared on Si (P) substrates to form MOS structure. The oxide films were annealed at different conditions and their crystal structures were determined by X‐ray diffraction (XRD). The dc electrical transport properties of the devices with amorphous and crystalline Nd oxide were investigated. The current‐temperature J(T) characteristics suggest that the carrier transport through the insulator follows Mott's variable‐range hopping (VRH) mechanism and its results were compared with the results obtained from X‐ray diffraction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal growth, thermal, optical and microhardness studies of tris (thiourea) zinc sulphate ‐ a semiorganic NLO material
Authors: Ramajothi J. , Dhanuskodi S. , Nagarajan K.
Published: April 2004

Tris (thiourea) zinc sulphate (ZTS), a semiorganic nonlinear optical (NLO) material has been synthesized at 30 °C. The solubility was determined in different solvents such as water, ethanol and water mixture of ethanol (1:1). Good quality single crystals with size 10 × 8 × 6 mm3 were grown by slow evaporation technique within three weeks with approximate growth rate of 0.5 mm/day. The grown crystals have been subjected to single crystal X‐ray diffraction to determine the unit cell dimensions and morphology. The TGA and DTA reveal that the material has good thermal stability. The UV‐Vis spectrum shows that the material has wide optical transparency in the entire visible region. The second harmonic generation was confirmed by Kurtz powder method. The birefringence of the crystal was measured in the visible region and it was found to vary with the wavelength. The microhardness test was carried out in (100) plane and the load dependent hardness was measured. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamic and lamella models relationship for the eutectic system benzoic acid – cinnamic acid
Authors: Sharma B. L. , Jamwal R. , Kant R.
Published: April 2004

The present investigation reveals the relationship between excess thermodynamic functions and the growth habits of the eutectic phases from the melt by continuous melt‐growth technique. Excess thermodynamic functions computed for different compositions of the benzoic acid – cinnamic acid eutectic system have been found consistent with the criteria of spontaneity and Planck formulation, and their reliability has been ascertained by the application of Guggenheim lattice theory. The results on the kinetics of anisotropic growth of the eutectic phases from the melt, evidentially evince the dislocation mechanism. Evidences have been obtained for a parabolic variation of mechanical strength with growth velocity of the eutectic material grown anisotropically from the melt at different intervals, which offer supporting complement to the dislocation mechanism governing the dependence of growth velocity on supercooling ΔT in the solidus – liquidus interface in a form : V = k(ΔT)2. A moderate anisotropic growth region has been explored by unique results of strength properties and microscopic results as well, to growing a layer of lamellae in a unidirectional lamina. An anisotropic eutectic composite lamellae lamina developed by moderate growth velocity (7.3 × 10‐8m3s‐1), is of greater interest offering optimum hardness, approximately varying between three‐and eight fold average increase in different modes of the mechanical strength in comparison to its isotropic growth carried out in an ice‐bath (∼273K), and manifold superior to its constituent phases irrespective of the growth mode. The directional lamina of uniform microstructural parameter lamellae, indicates that there is a perfect lamella‐ matrix equilibrium for which excess thermodynamic functions do vanish. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron microscopy investigations on structures of ZrO2‐rich phases in the quasibinary system ZrO2‐Zr3N4
Authors: Tham A. T. , Rödel C. , Lerch M. , Wang D. , Su D. S. , Klein‐Hoffmann A. , Schlögl R.
Published: April 2004

Slowly cooled nitrided zirconia samples were investigated and characterized by means of transmission electron microscopy (TEM). Besides the well‐known different modifications of ZrO2 some ZrO2‐rich oxynitride phases could be further found, called β‐type phases. An overview regarding the formation of such different structural modifications could be gained, supported by previously performed measurements using powder X‐ray diffractometry (XRD). Similar to fast cooled nitrided zirconia samples Zr(N,O), the slowly cooled ones also contain different kinds of ZrO2 precipitates, which can be obviously emphasized by using the methods of diffraction contrast. A super cell was successively built, derived from the unit cells of the β and β′ phase, in order to explain the structure of the observed modulated β″ phase. Agreements from the comparisons between experimental high resolution images and the simulated ones of such modulated structures confirm the suggested starting points. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)