bluuebunny/crossref_metadata_2025 huggingface dataset:
Impulsivity, personality disorders and pathological gambling severity
Authors: Steel Zachary , Blaszczynski Alex
Published: July 2002

Aims. The present study seeks to replicate and expand findings from earlier studies that pathological gamblers manifest elevated traits of impulsivity. Secondly, the study aims to elucidate the relationship between impulsivity, indices reflecting severity of pathological gambling and other measures of psychopathology and personality dysfunction. Design. Case series. Participants. Eighty‐two consecutive gamblers seeking treatment for problem gambling. Setting. Impulse Disorders Research Unit, School of Psychiatry, University of New South Wales, Australia. Measurements. Semi‐structured interview designed to obtain demographic information and gambling history, the South Oaks Gambling Screen, the Eysenck Impulsivity Scale, the Personality Disorder Questionnaire‐Revised, the Beck Depression Inventory and the Beck Anxiety Inventory. Findings. Results show elevated traits of impulsivity among clinic samples of pathological gamblers compared to normative data and show that impulsivity is related to the severity of gambling behaviour as measured by the South Oaks Gambling Questionnaire. A principal component analysis of the Eysenck Impulsivity Scale and the Personality Disorder Questionnaire‐Revised, demonstrated that the concept of the "antisocial‐impulsivist" identified by Blaszczynski, Steel & McConaghy (1997) is not only characterized by impulsivity and antisocial personality disorder but also by high loadings from other cluster B and cluster C personality disorders. Conclusion. This research supports the role of the construct of impulsivity in mediating the severity of gambling behaviour and associated behavioural and psychological disturbance among pathological gamblers presenting for treatment. Impulsivity is best understood as part of a general personality disorder structure characterized primarily by DSM‐III‐R Axis II cluster B and some cluster C personality disorders.
Factor structures for DSM‐IV substance disorder criteria endorsed by alcohol, cannabis, cocaine and opiate users: results from the WHO reliability and validity study
Authors: Nelson Christopher B. , Rehm Jurgen , Bedirhan T. , Grant Bridget , Chatterji Somnath
Published: July 2002

Aims. The factor structure of DSM‐IV substance disorder criteria is examined among alcohol, cannabis, cocaine and opiate users to determine the dimensionality of abuse and dependence criteria within each of these drug classes and whether a common construct can be generalized across drug classes. Design. 12‐month criterion prevalence was assessed as part of the World Health Organization's Study on the Reliability and Validity of the Alcohol and Drug Use Disorder Instruments in various settings at eight sites around the world using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). A majority of respondents were recruited from non‐treatment settings. In addition to exploratory factor analysis, confirmatory factor analysis was used to analyse factor structures using weighted least square methods and tetrachoric correlation matrices. Multi‐sample analysis techniques were used to model differences between drug‐classes. Findings. In the full data analyses identified a single factor solution for each user population and across user populations. However, analyses of data from users reporting low to moderate symptomatology identified a two‐dimensional construct among alcohol, cannabis and opiate users consisting of a major "dependence" factor and a lesser "abuse" factor. In addition, results showed that neither the abuse criterion "(A2) use in physical hazardous situations" or the dependence criterion "(D7) use despite knowledge of psychological/physical problems" were central to the latent construct in any of the user populations, except for D7 among alcohol users. Conclusions. The multi‐dimensional results found among users with low to moderate symptomatology indicate that: (1) previous results from relatively homogeneous populations may have been biased towards lesser order solutions, and that (2) the DSM‐IV substance disorder criteria describe at least two distinct phenomena, supporting the current DSM‐IV organization of substance disorder criteria. Further work needs to evaluate whether prevalent symptoms are present in random or predictable combinations, whether combinations reflecting a specific hierarchy of severity can be identified, and whether incident symptoms are accumulated in a predictable pattern, within specific user populations and across user populations.
Level of current and past adolescent cigarette smoking as predictors of future substance use disorders in young adulthood
Authors: Lewinsohn Peter M. , Rohde Paul , Brown Richard A.
Published: July 2002

Aims. This study examined the impact of adolescent cigarette smoking (life‐time use, recency, frequency and age of onset) on the occurrence of substance use disorders during young adulthood. Design. Participants were assessed while in high school (T1), approximately 1 year later (T2) and then after they had turned 24 years of age (T3). Setting. Adolescents were randomly selected at T1 from nine senior high schools in western Oregon. Participants. A subset (n=684) of 1709 adolescents who had been assessed regarding cigarette smoking during high school were evaluated for alcohol, cannabis and other drug abuse/dependence up to age 24. Measurements. Semi‐structured interviews provided information regarding life‐time use of cigarettes and chewing tobacco, age of smoking onset, frequency and quantity of cigarette smoking and quit efforts in adolescence. Diagnoses of substance abuse and dependence in young adulthood were made as per DSM‐IV. Findings. Life‐time smoking among older adolescents significantly increased the probability of future alcohol, cannabis, hard drug and multiple drug use disorders during young adulthood. Having been a former smoker did not reduce the risk of future substance use disorder, although having maintained smoking cessation for more than 12 months was associated with significantly lower rates of future alcohol use disorder. Daily smoking was associated with increased risk of future cannabis, hard drug and multiple drug use disorders. Among daily smokers, earlier smoking onset age predicted future substance use disorders. Conclusions. The results extend knowledge about relationships between cigarette smoking during adolescence and the development of substance use disorders during young adulthood, illustrating additional risks associated with early cigarette smoking. Future research is needed to examine potential causal associations.
The ecology and management of the Saiga antelope in Kazakhstan
Authors: Bekenov A. B. , Grachev Iu. A. , Milner‐Gulland E. J.
Published: July 2002

The ecology and management of the Saiga antelope Saiga tatarica tatarica, a nomadic herding species of the desert, semi‐desert and steppe ecosystems of Central Asia, are reviewed. The range area and population size of the Saiga in Kazakhstan have changed substantially since they were first described, declining rapidly through the nineteenth century to a low point in the 1920s, followed by recovery until the 1950s and subsequent stabilization. A detailed description is given of the Saiga’s habitat and the differences between the winter and summer pastures. The species feeds mainly on grasses, although herbs and shrubs are seasonally important. The migratory patterns of the species divide into directional seasonal migrations and less structured local movements. Group sizes are largest in the calving season and during the autumn migration. Harems are formed in early December. Fertility rates are high, with females giving birth in their first year of life, and routinely twinning thereafter. However, mortality rates are also high in years of drought and harsh winters. The major factors limiting populations include climate, parasites and diseases, predators, and anthropogenic factors. The major human influences are commercial hunting and poaching. Agriculture and habitat alteration are less important currently, although they were probably responsible for the division of the Kazakhstan population into three separate populations. The species was well managed in the Soviet period, with strong institutional structures. However, a new political era requires a re‐evaluation of the Saiga’s needs, in the face of a growing threat from poaching.
Tissue expression of transforming growth factor‐β1 and transforming growth factor‐α during wound healing in human skin explants
Authors: Kratz Gunnar , Compton Carolyn C.
Published: July 2002

In the dynamic and complex process of wound healing, locally produced growth factors are important mediators, although their actual roles have not been fully established. In the present study, the presence of transforming growth factor‐β1 and ‐α during the re‐epithelialization of full‐thickness wounds was investigated in an in vitro model of wound healing in human skin. The amounts of transforming growth factor‐β1 and ‐α secreted from the wound area were measured with enzyme immunoassays, and immunohistochemistry was used to study the localization of these two growth factors in the healing wound. The wounds were followed until they were completely re‐epithelialized. The results showed a continuous increase in secreted transforming growth factor‐β1 throughout the re‐epithelialization phase of healing followed by a decrease after its completion. The keratinocytes migrating out from the wound edges showed intense staining for transforming growth factor‐β1 which declined to the level of the surrounding epidermis after the wound was covered by a new epidermis. After the skin was wounded, a decrease both in secreted transforming growth factor‐α and in immunostaining for this growth factor was apparent. Even though a minor increase in the immunoreactivity for transforming growth factor‐α occurred after the completion of re‐epithelialization, no increase in secreted transforming growth factor‐α could be detected by enzyme immunoassay. These data suggest that keratinocytes modulate their expression of transforming growth factor‐β1 and ‐α during the wound healing process in human skin and that these changes may be controlled in part by autocrine pathways.
Ultrastructural analysis of fetal rabbit wounds
Authors: Mast Bruce A. , Haynes Jeffrey H. , Krummel Thomas M. , Kelman Cohen I. , Diegelmann Robert F.
Published: July 2002

Fetal wound healing proceeds rapidly with minimal inflammation and fibroplasia and little or no scar formation. These observations have led to the hypothesis that fetal wound healing more closely resembles regeneration rather than adult wound repair. To test this hypothesis, this study used ultrastructural analysis of fetal and adult fibroblasts and collagen to gain greater insight into differences in the healing processes. Full‐thickness, primarily closed linear incisions were created dorsally on 24‐day gestational age fetal rabbits (n = 9). The fetuses were killed 5 days later, and the wounds were excised and evaluated with transmission electron microscopy. Similarly, uninjured fetal skin of the same gestational age was obtained and analyzed. Adult rabbit dermal wounds were analyzed after 8 days of healing. Resting adult dermal fibroblasts had features of quiescent, inactive cells, whereas adult wound fibroblasts were highly active and filled with secretory vesicles. In contrast, both fetal normal dermal and wound fibroblasts appeared highly active and contained numerous secretory vesicles. In the adult wound, collagen fibril diameter was only 45% of the diameter of normal dermal collagen. However, fetal wound collagen fibrils were basically the same as normal dermal collagen, having a diameter that was 82% of the size of dermal collagen. These observations suggest that fetal wound fibroblasts do not require activation from an inactivated state and that fetal wound collagen deposition undergoes more rapid organization and maturation. These findings have significance in extending our understanding of the rapidity and functional superiority of fetal wound healing compared with adult wound healing.
Fibroblast senescence in pressure ulcers
Authors: Vande Berg Jerry S. , Rudolph Ross , Hollan Carol , Haywood‐Reid Patricia L.
Published: July 2002

Pressure ulcers appear as localized chronic wounds in the middle of normal functioning skin. This study focuses on pressure ulcer fibroblasts cultured from the ulcer bed, ulcer margin, and normal, nonulcerated skin adjacent to the wound. From these areas we show that pressure ulcer fibroblasts become prematurely senescent. Verification of senescence was based on failure of cell populations to undergo a 0.5 population doubling after 1 week in culture, light micro‐scopic appearance of late‐passage senescent cells in culture, light microscopic verification of senescence in vivo and in vitro by anti‐terminin staining, and ultrastructural identification of senescent fibroblasts by anti‐terminin colloidal gold labeling. Although not all ulcer fibroblasts are senescent, there is a range of proliferative ability. The senescent phenotype of ulcer fibroblasts remains intact in vitro as these cells remain viable but are unable to complete DNA synthesis. Fibroblast senescence is not uniform in chronic wounds but varies within areas of the ulcer bed and from patient to patient. Although ulcer fibroblasts exhibit limited proliferative ability, fibroblasts from the ulcer margin and adjacent normal skin show a continued ability to divide. However, in all areas of the wound, the mean generation time of the fibroblast population is longer than commonly observed for cultured human diploid fibroblasts. At first passage, the mean generation time for fibroblasts from all patients is significantly different (p = .001, analysis of variance) among fibroblasts from the ulcer bed (4.2 ± 2.2 days), ulcer margin (2.9 ± 1.3 days), and adjacent normal skin (1.9 ± 0.6 days). Analysis of the three cell groups by the post hoc Tukey test, using corrected p values shows that the difference between mean generation times among fibroblast populations from adjacent normal skin and ulcer bed are significantly different (p < 0.05), whereas the difference between fibroblasts from adjacent normal skin and ulcer margin and ulcer margin and ulcer bed are not significantly different (p > 0.05). These data may help to explain the poor response of certain pressure sores to aggressive medical treatment.
Efficient debridement of necrotic wounds using proteolytic enzymes derived from Antarctic krill: a double‐blind, placebo‐controlled study in a standardized animal wound model
Authors: Mekkes Jan R. , Le Poole I. Caroline , Das Pranab K. , Bos Jan D. , Westerhof Wiete
Published: July 2002

Wound healing can be accelerated by removing necrotic tissue. Various methods of wound debridement have been developed, including enzymatic debridement. Recently potent proteolytic enzymes were isolated from the intestine of Euphausia superba (Antarctic krill) that might be useful for degrading necrotic tissue. The purpose of this study was to evaluate the debriding properties of krill enzymes, using a specially designed animal model and a computerized analysis system. In 10 female domestic pigs, each weighing 20 kg, 6 artificial ulcers were made on each animal's back using electrokeratome, followed by application of trichloracetic acid. Ulcers were treated twice daily for 7 days with either krill enzymes at different concentrations or with saline. Reduction of necrotic tissue was measured daily using computerized wound analysis. Histological examination included the determination of bromodeoxyuridine incorporation in order to detect cell proliferation as well as routine stains. The debriding effect of krill enzymes at a concentration of ≥ 3.0 casein units per ml was significantly better than saline control treatment (p < 0.05). The effect was dose dependent, and granulation tissue formation was enhanced. In conclusion, krill enzymes are effective in wound debridement, as measured in this animal model.
Ultrastructural changes during contraction of collagen lattices by ocular fibroblasts
Authors: Porter Rebecca A. , Brown Robert A. , Eastwood Mark , Occleston Nicholas L. , Khaw Peng T.
Published: July 2002

Contraction and scarring of the cornea and conjunctiva following disease or injury are major causes of visual morbidity. The aim of this study was to identify any specific ultrastructural features of ocular fibroblast behavior in different collagen lattices in order to understand some of the mechanisms of cell‐mediated contraction. Normal human Tenon's capsule fibroblasts were cultured within both restrained and floating collagen lattices for periods of up to 13 days and then analyzed using transmission electron microscopy. The contractile force of these fibroblasts was also tested using the culture force monitor, an instrument capable of measuring the minute forces exerted by cells within a collagen lattice. The results showed differences in the behavior of fibroblasts cultured in the two gel models. The features seen in restrained gels suggest that fibroblasts were actively migrating across and through the lattice. These migratory features were not seen to the same extent in untethered gels, which lack the inherent tension and support of the tethered model. We hypothesize that contraction of the collagen matrix in tethered lattices is due to cellular migration and that this fact cannot be ascertained from untethered gels. Both lattice models have experimental value, but it is important to appreciate what mechanical signals cells receive from the matrix in order to understand cellular behavior.
Histological characterization of a delayed wound healing model in pig
Authors: Bernatchez Stéphanie F. , Parks Patrick J. , Grussing Duane M. , Matalas Shawn L. , Nelson Gwen S.
Published: July 2002

Chronic wounds, such as venous ulcers and pressure ulcers, frequently remain unresponsive to currently available treatments. Several animal models of wound healing have been published, including models of impaired healing developed to mimic the clinical condition of chronic wounds better. We used a delayed wound healing model in the pig that uses irradiation of the skin prior to creation of the surgical wounds and characterized it histologically. Radiation was used on one side of the back prior to making four full‐thickness wounds on each side. Clinical observations were performed to record granulation tissue, reepithelialization, and wound area as a function of time. Histology data were obtained at 1, 2, 3, and 4 weeks, and slides were stained with hematoxylin and eosin for general observations. Immunohistochemistry was performed using laminin as a marker for blood vessels, and the number, size, and circularity of blood vessels found in the granulation tissue were measured. Our results show that this model causes a delay in wound healing that is mostly apparent between days 7 and 15. Granulation tissue took more time to form and fill the wounds on the irradiated side, and blood vessels were slower to develop. Blood vessels were larger and more irregular in shape on the irradiated side than on the control side. After 2 weeks, healing resumed, indicating that the induced damage was not irreversible. These results suggest that this model can be used to test the effects of therapeutic approaches intended to treat chronic wounds.
Isolation of genes involved in intestinal remodeling during anuran metamorphosis
Authors: Amano Tosikazu
Published: July 2002

The small intestine of tadpoles is an organ that undergoes extensive changes during the process of morphogenesis. These changes include the transformation of the intestine from a single layer of larval epithelia with thin connective tissue to an extensively folded adult epithelia with a native connective tissue layer. To investigate the molecular events that lead to these dramatic morphological changes, a novel 5′‐suppression subtraction hybridization method was developed. We succeeded in identifying 24 upregulated genes in the remodeling intestine, of which 22 genes were unique Xenopus homologues of genes previously identified in other organisms. The homologue genes included transcription factors, extracellular matrix proteins, immunosuppressant‐binding proteins, enzymes, cell adhesion molecules, morphogenetic proteins, growth factors, member of the ubiquitin proteosome pathway, RNA‐binding proteins, and signal‐transduction proteins. This approach to study the molecular events of intestinal metamorphosis holds great potential for understanding this complex biological process.
The use of planarians to dissect the molecular basis of metazoan regeneration
Authors: Alvarado Alejandro Sánchez , Newmark Phillip A.
Published: July 2002

Freshwater planarians possess remarkable regenerative abilities that make them one of the classic model organisms for the study of regeneration. These free‐living members of the phylum Platyhelminthes are representatives of the simplest triploblastic organisms possessing bilateral symmetry and cephalization. Furthermore, planarians occupy an important position in the evolution of Metazoa, which allows for the possibility of vertically integrating molecular studies of regeneration in this organism to other, more widely studied animal model systems. Because of their relative simplicity, developmental plasticity, and evolutionary position, planarians are an attractive system to dissect the molecular processes underlying regeneration. The objective of this article is to present a molecular strategy to identify and functionally manipulate genes involved in the process of blastema‐derived regeneration. Ultimately, the genes identified in planarians and their interactions during regeneration will define a series of useful molecular templates that may help unravel the more complex epigenetic processes of vertebrate regeneration and may perhaps uncover the factors that make regeneration permissive in some, but not all, metazoans.
Stimulation of regeneration in mammals: pipe dream or realistic goal?
Authors: Carlson Bruce M.
Published: July 2002

This article covers a broad spectrum of mammalian regenerative phenomena, including the natural capacity for regeneration of organs and tissues and the classification of mammalian reparative responses. Several broad strategies have been formulated for the stimulation or enhancement of regeneration. Historically, the most common strategy has been to alter the environment surrounding a damaged or regenerating structure. A more contemporary approach to the stimulation of regeneration is the application of cellular engineering principles, which involve strategies such as the implantation of cultured cells, with or without appropriate substrates. Genetic engineering, involving the implantation of genetically engineered cells or the introduction of genes directly into cells in vivo is in the early stages of practical application, although certain laboratory applications have been quite successful.
Role of hair papilla cells on induction and regeneration processes of hair follicles
Authors: Matsuzaki Takashi , Yoshizato Katsutoshi
Published: July 2002

Hair dermal papilla cells are specialized mesenchymal cells that exist in the dermal papilla located at the bottom of hair follicles. These cells play pivotal roles in hair formation, growth, and cycling. Hair follicle formation is usually directed by an aggregation of dermal mesenchymal cells, the origin of dermal papilla cells, in the embryonic skin. We noticed that cultured dermal papilla cells also have hair‐forming activity and do not lose the activity even after long‐term cultivation, if they are cultured with conditioned medium from keratinocytes obtained from the sole or with a medium containing fibroblast growth factor. The secreted factors from keratinocytes and fibroblast growth factor are, therefore, important for maintaining the cellular properties of dermal papilla cells. Even if the hair bulb, including the hair matrix and the dermal papilla, has been removed from vibrissal follicles in vivo, the new hair matrix and papilla can regenerate from the rest of the follicle, and eventually a hair shaft regrows. It has been reported that hair bulb regeneration does not occur when the lower half of a hair follicle is removed. However, new hair bulbs were formed in the remaining upper halves of vibrissal follicles if the amputated follicles had been implanted under the kidney capsule. The formed bulbs were small and pelage‐type, not large vibrissa‐type. Histological studies showed that the new dermal papillae were derived from dermal sheath cells surrounding upper follicular epidermis, and the new hair matrices were produced from the follicular epidermis. Moreover, the upper halves of vibrissal follicles reformed large vibrissa‐type bulbs when they were associated with dermal papillae or cultured papilla cells and implanted in the kidney. Thus, dermal papilla cells and probably dermal sheath cells have the ability to induce and form hair bulbs under preferred environmental conditions. Attempts to identify the genes and proteins associated with hair‐forming activity of dermal papilla cells have been carried out. We and other groups successfully isolated the molecules that were specifically expressed in dermal papilla cells. The nature of the hair‐producing factors could be understood through the studies of these molecules.
Muscle morphogenetic protein induces myogenic gene expression in Swiss‐3T3 cells
Authors: Young Henry E. , Rogers John J. , Adkison Linda R. , Lucas Paul A. , Black Asa C.
Published: July 2002

Myogenesis is thought to be regulated by the MyoD family of regulatory genes, which includes MyoD, myogenin, MRF‐4/myf‐6, and myf‐5. In situ hybridization studies of vertebrate skeletal muscle development have shown the colocalization of the MyoD family of regulatory genes to specific stages of muscle development. Although many studies have analyzed the regulatory role of these genes during myogenesis, there have been few reports dealing with the activation of these myogenic regulatory genes by exogenous agents. We have previously shown that muscle morphogenetic protein induces myogenesis in clonal populations of avian pluripotent stem cells. The current study was designed to examine the ability of muscle morphogenetic protein to induce myogenesis in a clonal population derived from the established fibroblastic Swiss‐3T3 cell line. Swiss‐3T3 cells were cloned to generate separate cell populations, tested for pluripotency, propagated through 690 cell doublings, retested for pluripotency, treated with muscle morphogenetic protein, and examined for the induction of gene expression using probes for the transcription products of MyoD and myogenin. Muscle morphogenetic protein induced the expression of mRNAs for MyoD and myogenin, suggesting a role for this compound as an exogenous activator of myogenesis.
In vitro safety profile of G–CSF‐mobilized whole blood after storage for 7 days in an infusable‐grade L15 medium
Authors: De Kreuk Arne M. , Jonkhoff Andries R. , Zevenbergen Adri , Wilhelm Abraham J. , Van Oostveen Johan W. , Schuurhuis Gerrit J. , Huijgens Peter C.
Published: July 2002

BACKGROUND: G–CSF‐mobilized whole blood (WB) is a cost‐reducing and simple alternative for peripheral blood progenitor cell transplantation. Recently, it was demonstrated that mobilized WB supplemented with Leibovitz's L15 medium permitted prolonged preservation of clonogenic cells at ambient temperature. In this study, an infusable‐grade L15 medium (IG‐L15) was developed, and the safety profile of mobilized WB after 7 days of storage was investigated.

STUDY DESIGN AND METHODS: IG‐L15 was manufactured in a closed system under good manufacturing practice conditions. Proinflammatory cytokine levels and hemolysis in mobilized WB were determined after 7 days of storage in different containers and were compared with current clinical mobilized WB values after 1 to 3 days of storage at 4°C.

RESULTS: IG‐L15 and L15 maintained clonogenic cells equally. In the samples of mobilized WB that were returned to the patient, cytokine levels were not elevated in comparison with freshly collected mobilized WB. By using IG‐L15 in polystyrene‐coated cell culture bags, median (range) levels of 9.4 (2.2‐69.8) pg per mL (IL‐1β), 31.6 (6.1‐146.5) pg per mL (TNF‐α), 76.9 (15.5‐934.9) pg per mL (IL‐6), and 7195 (104‐205,600) pg per mL (IL‐8) were found after 7 days. Higher cytokine levels were found with L15 and different containers. He‐ molysis was less than 0.5 g per dL in all cases.

CONCLUSION: The storage of mobilized WB for 7 days in IG‐L15 at ambient temperature is possible with adequate preservation of clonogenic cells, but cytokine levels may require plasma removal before return.
Carbamazepine versus Valproate Monotherapy for Epilepsy: A Meta‐analysis
Authors: Marson Anthony G. , Williamson Paula R. , Clough Helen , Hutton Jane L. , Chadwick David W. , On Behalf Of The Epilepsy Monotherapy Trial Group
Published: July 2002

Summary:  Purpose: To provide an overview of the evidence comparing carbamazepine (CBZ) and valproate (VPA) monotherapy for epilepsy, investigating whether existing data support the current practice of preferring CBZ for partial‐onset and VPA for generalized‐onset seizures.

Methods: We performed meta‐analysis of randomized controlled trials by using individual patient data. Our strategy included searches of (a) Medline, 1966–2000; (b) The Cochrane Library 2000, issue 4; and (c) the pharmaceutical industry. Outcome measures were time to discontinuation of allocated treatment, time to 12‐month remission, and time to first seizure after randomization. Results are expressed as hazard ratios (HRs; 95% CI), where HR>1 indicates that an event is more likely with VPA. A test for an interaction between treatment and seizure type (partial vs. generalized onset) also was undertaken.

Results: Data were available for 1,265 patients from five trials. Overall results (HR, 95% CI) were Time to treatment discontinuation, 0.97 (0.79–1.18); 12‐Month remission, 0.87 (0.74–1.02); and First seizure, 1.09 (0.96–1.25), suggesting no overall difference for these outcomes. The test for an interaction between Treatment and Seizure type was significant for time to first seizure, but for no other outcome. The age distribution of adults classified as having generalized seizures indicated that significant numbers of patients may have had their seizures misclassified.

Conclusions: We found some evidence to support the preference of CBZ for partial‐onset seizures, but no evidence to support the preference of VPA for generalized‐onset seizures. Confidence intervals are too wide to infer equivalence. Misclassification of patients may have confounded our results and has important implications for future trials.
Correlation in time-dependent density-functional theory
Authors: Hessler Paul , Maitra Neepa T. , Burke Kieron
Published: July 2002

The exact time-dependent correlation energy in time-dependent density-functional theory is shown to sometimes become positive, which is impossible with most present TDDFT approximations. Both the correlation potential and energy can be strongly nonlocal in time. A new inequality is derived for the time-dependent exchange-correlation energy. The correlation energy appears to scale to a constant function of scaled time in the high-density limit. In the linear response regime, the correlation energy is shown to become purely adiabatic, but the correlation potential is generally nonadiabatic. The usefulness of the virial theorem as a test of numerical accuracy is demonstrated. All results are found or inspired by exact numerical solution of a simple model system (Hooke’s atom), and inversion of the corresponding Kohn–Sham equations.
Equi-g(r) sequence of systems derived from the square-well potential
Authors: Sakai H. , Stillinger F. H. , Torquato S.
Published: July 2002

We introduce the idea of an “equi-g(r) sequence.” This consists of a series of equilibrium many-body systems which have different number densities ρ but share, at a given temperature, the same form of pair correlation function, termed “target g(r).” Each system is defined by a pair potential indexed by ρ as in uρ(r). It is shown that for such a sequence a terminal density ρ⋆ exists, beyond which no physically realizable system can be found. As an illustration we derive explicit values of ρ⋆ for target g(r) that is based on a square-well potential in the limit ρ→0. Possible application of this terminal phenomenon to the investigation into limiting amorphous packing structures of hard spheres is proposed. Virial expansions of uρ(r) and pressure are carried out and compared with the corresponding expressions for imperfect gas. The behaviors of uρ(r) and pressure close to ρ=ρ⋆ are examined as well, and associated exponents extracted when they exist. The distinction between equi-g(r) sequence and the related, recently introduced concept of “iso-g(2) process” is briefly discussed.
Association of two semiflexible polyelectrolytes by interchain linkers: Theory and simulations
Authors: Borukhov Itamar , Lee Kun-Chun , Bruinsma Robijn F. , Gelbart William M. , Liu Andrea J. , Stevens Mark J.
Published: July 2002

The aggregation of two highly charged semiflexible polyelectrolytes in the presence of generalized linkers is studied theoretically. This model provides insight into biological processes such as DNA condensation and F-actin self-assembly induced by either multivalent counterions or bundling proteins. The interplay between the bending rigidity of the chains and their electrostatic interactions leads to an effective interlinker interaction that is repulsive at large distances and attractive at short ones. We find a rounded phase transition from a dilute linker gas where the chains form large loops to a dense disordered linker fluid where the chains are almost parallel. The onset of chain pairing occurs as soon as the free energy of a pair of chains becomes lower than that of two isolated chains and is located well within the crossover regime between the two linker phases. Our main findings are confirmed by molecular dynamics simulations of two semiflexible charged chains in a mixture of monovalent and polyvalent counterions. This simple model allows us to recover qualitative features of experimental aggregation diagrams of DNA and F-actin and can also be used to study DNA denaturation.
Simultaneous measurements of all three components of velocity and vorticity vectors in a lobed jet flow by means of dual-plane stereoscopic particle image velocimetry
Authors: Hu Hui , Saga Tetsuo , Kobayashi Toshio , Taniguchi Nubuyuki
Published: July 2002

Results from an advanced particle image velocimetry (PIV) technique, named as dual-plane stereoscopic PIV technique, for making simultaneous measurements of all three components of velocity and vorticity vectors are presented for a lobed jet flow. The dual-plane stereoscopic PIV technique uses polarization conservation characteristic of Mie scattering to achieve simultaneous stereoscopic PIV measurements at two spatially separated planes. Unlike “classical” PIV systems or conventional stereoscopic PIV systems, which can only get one component of vorticity vectors, the present dual-plane stereoscopic PIV system can provide all three components of velocity and vorticity distributions in fluid flows instantaneously and simultaneously. The evolution and interaction characteristics of the large-scale streamwise vortices and azimuthal Kelvin–Helmholtz vortices in the lobed jet flow are revealed very clearly and quantitatively from the simultaneous measurement results of the dual-plane stereoscopic PIV system. A discussion about the satisfaction of the measurement results of the present dual-plane stereoscopic PIV system to mass conservation equation is also conducted in the present paper to evaluate the error levels of the measurement results.
Electron transport in strained Si inversion layers grown on SiGe-on-insulator substrates
Authors: Gámiz F. , Cartujo-Cassinello P. , Roldán J. B. , Jiménez-Molinos F.
Published: July 2002

We show by simulation that electron mobility and velocity overshoot are greater when strained inversion layers are grown on SiGe-On-insulator substrates (strained Si/SiGe-OI) than when unstrained silicon-on-insulator (SOI) devices are employed. In addition, mobility in these strained inversion layers is only slightly degraded compared with strained bulk Si/SiGe inversion layers, due to the phonon scattering increase produced by greater carrier confinement. Poisson and Schroedinger equations are self-consistently solved to evaluate the carrier distribution in this structure. A Monte Carlo simulator is used to solve the Boltzmann transport equation. Electron mobility in these devices is compared to that in SOI inversion layers and in bulk Si/SiGe inversion layers. The effect of the germanium mole fraction x, the strained-silicon layer thickness, TSi, and the total width of semiconductor (Si+SiGe) slab sandwiched between the two oxide layers, Tw were carefully analyzed. We observed strong dependence of the electron mobility on TSi, due to the increase in the phonon scattering rate as the silicon layer thickness is reduced, a consequence of the greater confinement of the carriers. This effect is less important as the germanium mole fraction, x, is reduced, and as the value of TSi increases. For TSi>20 nm, mobility does not depend on TSi, and maximum mobility values are obtained.
Optical study of high-biased AlGaN/GaN high-electron-mobility transistors
Authors: Shigekawa Naoteru , Shiojima Kenji , Suemitsu Tetsuya
Published: July 2002

Microscopic electroluminescence (EL) and photoluminescence (PL) measurements of high-biased AlGaN/GaN high-electron-mobility transistors are reported. We observed that the EL intensity reveals peaks around the edge of the channel and the electron temperature there is higher than the electron temperature at the center of the channel. These EL features were found to be consistent with the change in the junction temperature, which we locally estimated by comparing the PL data with measurements in raised ambient temperatures.
3nj-coefficients of su(1,1) as connection coefficients between orthogonal polynomials in n variables
Authors: Lievens S. , Van der Jeugt J.
Published: July 2002

In the tensor product of n+1 positive discrete series representations of su(1,1), a coupled basis vector can be described by a certain binary coupling tree. To every such binary coupling tree, polynomials Rl(k)(x) and Rl(k)(x) are associated. These polynomials are n-variable Jacobi and continuous Hahn polynomials, and are orthogonal with respect to a weight function. The connection coefficients expressing such a polynomial associated with a given binary coupling tree in terms of those polynomials associated with another binary coupling tree are proportional to 3nj-coefficients of su(1,1).
Reconstruction of Abel-transformable images: The Gaussian basis-set expansion Abel transform method
Authors: Dribinski Vladimir , Ossadtchi Alexei , Mandelshtam Vladimir A. , Reisler Hanna
Published: July 2002

In this article we present a new method for reconstructing three-dimensional (3D) images with cylindrical symmetry from their two-dimensional projections. The method is based on expanding the projection in a basis set of functions that are analytical projections of known well-behaved functions. The original 3D image can then be reconstructed as a linear combination of these well-behaved functions, which have a Gaussian-like shape, with the same expansion coefficients as the projection. In the process of finding the expansion coefficients, regularization is used to achieve a more reliable reconstruction of noisy projections. The method is efficient and computationally cheap and is particularly well suited for transforming projections obtained in photoion and photoelectron imaging experiments. It can be used for any image with cylindrical symmetry, requires minimal user’s input, and provides a reliable reconstruction in certain cases when the commonly used Fourier–Hankel Abel transform method fails.
Numerical study of fast ignition of ablatively imploded deuterium–tritium fusion capsules by ultra-intense proton beams
Authors: Temporal M. , Honrubia J. J. , Atzeni S.
Published: July 2002

Compression and ignition of deuterium–tritium fuel under conditions relevant to the scheme of fast ignition by laser generated proton beams [Roth et al., Phys. Rev. Lett. 86, 436 (2001)] are studied by numerical simulation. Compression of a fuel containing spherical capsule driven by a pulse of thermal radiation is studied by a one-dimensional radiation hydrodynamics code. Irradiation of the compressed fuel by an intense proton beam, generated by a target at distance d from the capsule center, and subsequent ignition and burn are simulated by a two-dimensional code. A robust capsule, absorbing 635 kJ of 210 eV (peak) thermal x rays, with fusion yield of almost 500 MJ, has been designed, which could allow for target gain of 200. On the other hand, for a reasonable proton spectrum the required proton beam energy Eig, exceeds 25 kJ (for d=4 mm), even neglecting beam losses in the hohlraum and assuming that the beam can be focused on a spot with radius of 10 μm. The effects of proton range lengthening due to the increasing plasma temperature and of beam temporal spread caused by velocity dispersion are discussed. Ways to reduce Eig to about 10 kJ are discussed and analyzed by simulations.
On the Chemla effect in molten alkali nitrates
Authors: Ribeiro Mauro C. C.
Published: July 2002

The Chemla effect concerns the strong composition dependence of the internal ionic mobilities of cations in mixtures of two molten salts with a common anion, in which the mobility of the large cation can be higher than the small one at low concentrations of the latter. Molecular dynamics simulations of molten (Li,Cs)NO3, (Li,K)NO3, (Li,Na)NO3, (Na,Cs)NO3, each at two different compositions at a given temperature, and also pure LiNO3 and pure KNO3, have been performed with the aim of reproducing the Chemla effect. The key role played by anion polarization on the Chemla effect in molten alkali nitrates is demonstrated by comparing the calculated mobilities using nonpolarizable and polarizable models. Polarization effects were included in the simulations by using a previously proposed fluctuating charge model (FCM) for the NO3− anion. It is shown that a single potential model for a (M1,M2)NO3 mixture gives the correct composition dependence of the M1 and the M2 mobilities provided that polarization effects are included in the model. The FCM is thus transferable between different systems, but not its nonpolarizable counterpart. Structure and dynamics of the simulated systems are discussed in light of proposed models for the Chemla effect.
Thickness-dependent dielectric constants of (Ba,Sr)TiO3 thin films with Pt or conducting oxide electrodes
Authors: Hwang Cheol Seong
Published: July 2002

The decrease in the measured dielectric constant of sputter-deposited (Ba,Sr)TiO3 thin films having Pt electrodes with decreasing dielectric film thickness was analyzed by a combination of theories regarding the finite charge-screening length of the metal electrode and the intrinsic-dead layer of the dielectric surface. It was found that the decreasing dielectric constant was mainly due to the metal electrode capacitance rather than the intrinsic-dead-layer capacitance. The almost film-thickness-independent dielectric constant of the (Ba,Sr)TiO3 thin films with conducting oxide electrodes, IrO2 and SrRuO3, when the dielectric film thickness >20 nm, was attributed to the very high capacitance values of the charge-screening layer of the oxide electrodes. The very high capacitance value appeared to originate from the strain-induced high dielectric constant of the oxide electrodes.
Corrections to scaling in the hydrodynamic properties of dilute polymer solutions
Authors: Dünweg Burkhard , Reith Dirk , Steinhauser Martin , Kremer Kurt
Published: July 2002

We discuss the hydrodynamic radius RH of polymer chains in good solvent, and show that the leading order correction to the asymptotic law RH∝Nν (N degree of polymerization, ν≈0.59) is an “analytic” term of order N−(1−ν), which is directly related to the discretization of the chain into a finite number of beads. This result is further corroborated by exact calculations for Gaussian chains, and extensive numerical simulations of different models of good-solvent chains, where we find a value of 1.591±0.007 for the asymptotic universal ratio RG/RH, RG being the chain’s gyration radius. For Θ chains the data apparently extrapolate to RG/RH≈1.44, which is different from the Gaussian value 1.5045, but in accordance with previous simulations. We also show that the experimentally observed deviations of the initial decay rate in dynamic light scattering from the asymptotic Benmouna–Akcasu value can partly be understood by similar arguments.
Permeability of periodic arrays of cylinders for viscoelastic flows
Authors: Alcocer F. J. , Singh P.
Published: July 2002

In this paper we numerically investigate the motion of viscoelastic liquids passing through two-dimensional periodic arrays of cylindrical particles using the finite element method. The viscoelastic liquid is modeled by the Chilcott–Rallison version of the finitely extensible, nonlinear elastic (FENE) dumbbell model. The permeability and the viscoelastic stress distribution are studied as functions of the dimensionless relaxation time De and the dimensionless wave number kD, where k=2π/λ is the wave number, λ is the distance between the particles in the flow direction and D is the cylinder diameter. The porosity and D are held fixed. Our simulations show that for a fixed value of De the viscoelastic permeability increases with kD, but, as is the case for Newtonian fluid [Alcocer, Kumar, and Singh, Phys. Rev. E 59, 711 (1999)], this increase is not monotonic. The permeability decreases between kD≈5.0, where it is locally maximum, and kD≈7.7, where it is locally minimum. The difference between the locally maximum and minimum values of permeability increases with increasing De. When De=O(1) the locally minimum value of the permeability is ∼40% smaller than the value at the local maximum. This implies that a substantial change in permeability can be achieved by changing the distance between the particles in the flow direction while keeping De, D, and porosity fixed.
Fully leaky guided mode study of the flexoelectric effect and surface polarization in hybrid aligned nematic cells
Authors: Jewell S. A. , Sambles J. R.
Published: July 2002

The fully leaky guided-mode optical-waveguide technique has been used to characterize the tilt profiles in two E7-filled hybrid-aligned nematic cells. The director distortion was measured with ac and dc voltages applied perpendicular to the substrates. By comparing the tilt profiles with model profiles produced using a free-energy minimization program, the flexoelectric coefficient of E7 at 20 °C has been measured as +1.5±0.2×10−11 C m. The effect of surface polarization in the cells has also been observed. This surface polarization is attributed to the influence of the homeotropic surface. The dipole alignment imbalance of the liquid crystal at the homeotropic surface has then been estimated.