bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Hydrocarbon Chain Length on Adsorption of Cationic Surfactants onto Clinoptilolite
Authors: Ersoy Bahri , Çelik Mehmet S.
Published: April 2003

The adsorption behavior of quaternary ammonium cationic surfactants with different hydrocarbon chain lengths, i.e. HDTMA (hexadecyltrimethylammonium), TDTMA (tetradecyltrimethylammonium) and DDTMA (dodecyltrimethylammonium), onto clinoptilolite has been investigated. The adsorption isotherms of these surfactants are correlated with the ζ potential curves of clinoptilolite. Accordingly, the applicability of the hemimicelle hypothesis to the adsorption of cationic surfactants at the clinoptilolite/water interface considering in the electrical double layer (EDL) of clinoptilolite is discussed. Even though the adsorption occurs in the EDL of clinoptilolite, the adsorption of HDTMA, TDTMA and DDTMA onto clinoptilolite is not conveniently described by the hemimicelle hypothesis. The absence of all expected marked increase in the ζ potential curves at the hemimicelle concentration is ascribed to the large external cation exchange capacity of clinoptilolite. The hydrocarbon chain length of surfactant molecules is found to have a significant effect on the ion exchange as well as hydrophobic interaction mechanisms. The effectiveness of both ion exchange and hydrophobic interactions increases with increasing chain length, and so the greatest surfactant adsorption onto clinoptilolite was obtained by HDTMA.
Structural Features of a Clay Film Hybridized with a Zwitterionic Molecule as Analyzed by Second-Harmonic Generation Behavior
Authors: Ogata Yuichirou , Kawamata Jun , Chong Chin-Hong , Yamagishi Akihiko , Saito Gunzi
Published: April 2003

Hybrid Langmuir-Blodgett (LB) films of a single clay layer and a donor-(π-electron system)-acceptor (Dδ-π-Aδ−) zwitterionic molecule (ind-TCNQ), prepared from 1,3,3-trimethyl-2-methyleneindoline (donor) and 7,7,8,8-tetracyanoquinodimethane (acceptor) were prepared. The characteristics of the electrostatic interaction between the clay layer and the ind-TCNQ molecules were investigated. The amount of ind-TCNQ molecules spread onto the air-water interface was increased systematically so that mono- and multi-layers of the molecules could be formed on the clay layer. The hybrid LB films, which were deposited onto a solid substrate, were characterized by means of UV-vis absorption spectroscopy and optical second-harmonic generation measurement. The amount of ind-TCNQ molecules adsorbed on the clay layer increased with an increase in the amount of ind-TCNQ molecules spread onto the air-water interface. On the other hand, the SHG intensities of the films did not change with the change in amount of ind-TCNQ spread. The results indicate that the electrostatic interaction between the clay layer and the ind-TCNQ molecules operates only in the region where the ind-TCNQ molecules are in direct contact with the clay layer.
The Destructive Role of Diffusion on Clay Membrane Behavior
Authors: Shackelford Charles D. , Lee Jae-Myung
Published: April 2003

The results of a combined chemico-osmotic/diffusion experiment conducted on a geosynthetic clay liner (GCL) containing Na-bentonite illustrate the destructive role of diffusion on the ability of the GCL to act as a semipermeable membrane. The experiment is conducted by maintaining a concentration difference of 5 mM CaCl2 across the GCL specimen while preventing the flow of solution through the specimen. A time-dependent membrane efficiency is derived from measured pressure differences induced across the specimen in response to the applied concentration difference. The diffusive mass fluxes of the solutes (Cl− and Ca2+) through the specimen are also measured simultaneously. An initial increase in induced pressure difference across the specimen to a peak value of 19.3 kPa is observed, followed by a gradual decrease to zero. The decrease in induced pressure difference is consistent with compression of diffuse double layers between clay particles and particle clusters due to diffusion of Ca2+, resulting in a concomitant increase in pore sizes and decrease in the observed membrane behavior. The time required for effective destruction of the initially observed semipermeable membrane behavior correlates well with the time required to achieve steady-state Ca2+ diffusion. The results have important implications for the ability of clays to sustain membrane behavior.
Arsenic Sorption onto Soils Enriched in Mn and Fe Minerals
Authors: Deschamps Eleonora , Ciminelli Virginia S. T. , Weidler Peter G. , Ramos Aline Y.
Published: April 2003

The As sorption capacity of a natural Mn and Fe mineral-containing sample from the Iron Quadrangle province, Brazil, was investigated. A detailed mineralogical identification was obtained by combining X-ray diffraction analyses (with Rietveld refinement), X-ray fluorescence spectroscopy, optical microscopy, and scanning electron microscopy coupled with X-ray energy dispersive spectrometry-EDS. The oxidation state of the adsorbed As species was determined by X-ray absorption near edge structure spectroscopy. The results demonstrate that the presence of naturally occurring Mn oxides promotes the effective oxidation of As (III) to As(V). Also, the Mn minerals show a significant uptake of both the trivalent and pentavalent As species. This study demonstrates that the combined influences of As(III) depletion by oxidation and adsorption on a natural oxide sample consisting of Mn minerals and Fe oxides may effectively contribute to the reduction the As concentration in waters.
Evolution of Clay Minerals in a Chronosequence of Poldered Sediments Under the Influence of a Natural Pasture Development
Authors: Velde B. , Goffé B. , Hoellard A.
Published: April 2003

Clay minerals appear to change significantly under the influence of pasture development on poldered sediments in the Baie d'Authie area (Somme, France). Cores 40–90 cm deep from recent salt marsh sediments and poldered sediments developing grass pastures since 1737, 1575 and 1158 indicate that the natural mineral suite of kaolinite, mica, illite, and two disordered mixed-layered illite-smectite (I-S) phases common to the sedimentary input changes gradually but significantly in the materials. In the oldest, best-developed profile, there is a dominance of a disordered, illitic I-S in the humic upper part of the profile and a more abundant, more smectitic I-S mineral below. It appears that grass-derived humic materials tend to stabilize closed (collapsed) or illitic behavior in I-S clays. The natural evolution of the sediment (lower part of the profile) is towards a smectitic clay assemblage. Destruction of organic matter of the smectitic I-S minerals by oxidation indicates that this material can significantly modify the physical behavior of the clays keeping the structure open to polar molecules.
A Simple Sample-Mounting Method for Random Powder X-Ray Diffraction
Authors: Zhang Guoping , Germaine John T. , Martin R. Torrence , Whittle Andrew J.
Published: April 2003

This paper describes an improved simple, sample-mounting method for random powder X-ray diffraction (XRD), namely the razor tamped surface (RTS) method, which prepares a powder mount by tamping the loose powder with the sharp edge of a razor blade. Four kaolinites and a quartz powder were used to evaluate the RTS method by quantifying the degree of orientation in the sample mounts using orientation indices. Comparisons between the RTS and other published simple methods, consisting of front loading, back loading and side loading, indicate that the RTS method produces minimum packing density and minimum preferred orientation in the powder mounts of all five samples. The quartz powder used in this study does exhibit a tendency to preferred orientation. The mechanism by which the RTS method reduces preferred orientation is examined by comparing the width of the sharp blade edge with the size of clay particles. The advantages and disadvantages of the RTS method are also discussed.
Contact and the ecology of racial division: Some varieties of informal segregation
Authors: Dixon John , Durrheim Kevin
Published: April 2003

The analysis of contact between groups must proceed from an uncomfortable realization. Notwithstanding its formal abolition in many societies, segregation remains pervasive as an informal mechanism for ordering and defining social relations. Social psychologists' tendency to investigate contact under ‘optimal’ conditions may obscure this fact. This article discusses an observational study that attempted to chart some varieties of informal segregation on an ‘open’ beach in post‐apartheid South Africa. The study used a novel methodology to plot the ecology of racial distribution within this public setting over time. The analysis, which included measures of dissimilarity (D) and exposure (P), indicated that processes of segregation operated in various ways to limit the opportunities for racial contact. Follow‐up interviews conducted with ‘white’ holiday‐makers suggested that such processes embodied shared assumptions about the ‘proper’ socio‐spatial organization of race relations. Some implications for research on the contact hypothesis are discussed.
Taking a stand: Using psychoanalysis to explore the positioning of subjects in discourse
Authors: Frosh Stephen , Phoenix Ann , Pattman Rob
Published: April 2003

This paper is concerned with thinking through the cultural construction of personal identities whilst avoiding the classical social‐individual division. Our starting point is the notion that there is no such thing as ‘the individual’, standing outside the social; however, there is an arena of personal subjectivity, even though this does not exist other than as already inscribed in the sociocultural domain. Our argument is that there are psychoanalytic concepts which can be helpful in exploring this ‘inscription’ and thus in explaining the trajectory of individual subjects; that is, their specific positioning in discourse. The argument is illustrated by data from a qualitative study of young masculinities, exploring the ways in which some individual boys take up positions in various degrees of opposition to the dominant ideology of ‘hegemonic’ masculinity.
Risk: From perception to social representation
Authors: Joffe Hélène
Published: April 2003

This paper is concerned with how people make meaning of the risks they face. It explores certain assumptions of the risk perception approaches, which dominate the area. It argues that despite changes currently taking place in the field, such models still focus on static, intrapersonal processes, with many viewing human thinking as analogous to erroneous information processing. In the place of an individual ‘deficit’ focus, the paper proposes a more intersubjective theory of the response to risk. Social representations theory is evaluated and its validity assessed by highlighting empirical work on representations of biotechnological and health risks. The review reveals that the response to risk is a highly social, emotive and symbolic entity. Therefore a theory and methods appropriate to such qualities are proposed, to produce a valid psychology of risk.
Moderating role of attitudinal ambivalence within the theory of planned behaviour
Authors: Conner Mark , Povey Rachel , Sparks Paul , James Rhiannon , Shepherd Richard
Published: April 2003

The present study examined the moderating role of attitudinal ambivalence within the theory of planned behaviour (TPB). Attitude, subjective norm, perceived behavioural control (PBC), behavioural intentions and self‐reported behaviour were assessed in relation to 20 healthy eating behaviours in a prospective questionnaire design in 232 members of the general public in the UK. Between‐participants univariate and multivariate analyses indicated attitude‐behaviour and PBC‐behaviour relationships to be weaker in higher ambivalence compared to lower ambivalence respondents. These effects were confirmed in within‐participants analyses. The findings are discussed in terms of the role of ambivalence in furthering our understanding of relationships in the TPB.
Personality systems interactions theory and the theory of planned behaviour: Evidence that self‐regulatory volitional components enhance enactment of studying behaviour
Authors: Orbell Sheina
Published: April 2003

The role of volitional components specified by personality systems interactions theory in enhancing behavioural prediction was examined in a longitudinal investigation of students' studying. Participants completed measures specified by the theory of planned behaviour and questionnaire measures of ‘conscious attention control’, ‘implicit attention control’ and ‘self‐determination’ from the volitional components inventory. Behaviour was assessed 2 weeks later. Regression analyses showed that volitional components increased variance explained in behaviour by 10–18%, after taking into account strength of motivation to study assessed by attitude, subjective norm, perceived behavioural control and intention from the theory of planned behaviour. Moreover, consistent with elements of personality systems interactions theory, moderator effects were obtained. Participants who reported self‐determination, conscious attention control and implicit attention control were more likely to enact their intentions. Volitional components were also associated with increased studying among participants who perceived a low subjective norm for studying. Volitional components improved prediction of studying after accounting for past behaviour in the regression models.
Disrupting the sexual double standard: Young women's talk about heterosexuality
Authors: Jackson Susan M. , Cram Fiona
Published: April 2003

Despite significant changes in the social landscape over the past two decades, much ethnographic research suggests that young women's negotiations of (hetero)sexuality remain dominated by the sexual double standard. Within the sexual double standard, an active, desiring sexuality is positively regarded in men, but denigrated and regulated by negative labelling in women. This article analyses young women's talk on the subject of negotiating (hetero)sexual relationships, drawn from focus‐group interviews with six groups of young women aged 16–18 years. A feminist, post‐structuralist form of discourse analysis is used to analyse the material, the aim being to examine young women's talk about (hetero)sexuality from the standpoints of agency and resistance. Analyses identified various ways in which the sexual double standard was disrupted, including challenging the language of the sexual double standard, articulating sexual desire, and positioning of self and (hetero)sex within alternative discourses. The findings also suggest, however, that voices of resistance to the sexual double standard may be muted and individual rather than collective, and that, accordingly, every effort should be made by those working with young women to recognize and support attempts to disrupt the sexual double standard.
Investigating multiple components of attitude, subjective norm, and perceived control: An examination of the theory of planned behaviour in the exercise domain
Authors: Rhodes Ryan E. , Courneya Kerry S.
Published: April 2003

The presence of two subcomponents within each theory of planned behaviour (TPB) concept of attitude (affective and instrumental), subjective norm (injunctive and descriptive), and PBC (self‐efficacy and controllability) has been widely supported. However, research has not examined whether the commonality of variance between these components (i.e. a general factor) or the specificity of variance within the subcomponents influences intention and behaviour. Therefore, the purpose of this study was to examine the optimal conceptualization of either two subcomponents or a general common factor for each TPB concept within an omnibus model. Further, to test whether conceptualizations may differ by population even within the same behavioural domain, we examined these research questions with 300 undergraduates (M age = 20) and 272 cancer survivors (M age = 61) for exercise behaviour. Results identified that a general subjective norm factor was an optimal predictive conceptualization over two separate injunctive and descriptive norm components. In contrast, a specific self‐efficacy component, and not controllability or a general factor of PBC, predicted intention optimally for both samples. Finally, optimal models of attitude differed between the populations, with a general factor best predicting intention for undergraduates but only affective attitude influencing intention for cancer survivors. The findings of these studies underscore the possibility for optimal tailored interventions based on population and behaviour. Finally, a discussion of the theoretical ambiguity of the PBC concept led to suggestions for future research and possible re‐conceptualization.
Television Watching and Other Sedentary Behaviors in Relation to Risk of Obesity and Type 2 Diabetes Mellitus in Women
Authors: Hu Frank B. , Li Tricia Y. , Colditz Graham A. , Willett Walter C. , Manson JoAnn E.
Published: April 2003

Context

Current public health campaigns to reduce obesity and type 2 diabetes have largely focused on increasing exercise, but have paid little attention to the reduction of sedentary behaviors.

Objective

To examine the relationship between various sedentary behaviors, especially prolonged television (TV) watching, and risk of obesity and type 2 diabetes in women.

Design, Setting, and Participants

Prospective cohort study conducted from 1992 to 1998 among women from 11 states in the Nurses' Health Study. The obesity analysis included 50 277 women who had a body mass index (BMI) of less than 30 and were free from diagnosed cardiovascular disease, diabetes, or cancer and completed questions on physical activity and sedentary behaviors at baseline. The diabetes analysis included 68 497 women who at baseline were free from diagnosed diabetes mellitus, cardiovascular disease, or cancer.

Main Outcome Measures

Onset of obesity and type 2 diabetes mellitus.

Results

During 6 years of follow-up, 3757 (7.5%) of 50 277 women who had a BMI of less than 30 in 1992 became obese (BMI ≥30). Overall, we documented 1515 new cases of type 2 diabetes. Time spent watching TV was positively associated with risk of obesity and type 2 diabetes. In the multivariate analyses adjusting for age, smoking, exercise levels, dietary factors, and other covariates, each 2-h/d increment in TV watching was associated with a 23% (95% confidence interval [CI], 17%-30%) increase in obesity and a 14% (95% CI, 5%-23%) increase in risk of diabetes; each 2-h/d increment in sitting at work was associated with a 5% (95% CI, 0%-10%) increase in obesity and a 7% (95% CI, 0%-16%) increase in diabetes. In contrast, standing or walking around at home (2 h/d) was associated with a 9% (95% CI, 6%-12%) reduction in obesity and a 12% (95% CI, 7%-16%) reduction in diabetes. Each 1 hour per day of brisk walking was associated with a 24% (95% CI, 19%-29%) reduction in obesity and a 34% (95% CI, 27%-41%) reduction in diabetes. We estimated that in our cohort, 30% (95% CI, 24%-36%) of new cases of obesity and 43% (95% CI, 32%-52%) of new cases of diabetes could be prevented by adopting a relatively active lifestyle (<10 h/wk of TV watching and ≥30 min/d of brisk walking).

Conclusions

Independent of exercise levels, sedentary behaviors, especially TV watching, were associated with significantly elevated risk of obesity and type 2 diabetes, whereas even light to moderate activity was associated with substantially lower risk. This study emphasizes the importance of reducing prolonged TV watching and other sedentary behaviors for preventing obesity and diabetes.
Weight Loss With Self-help Compared With a Structured Commercial Program
Authors: Heshka Stanley , Anderson James W. , Atkinson Richard L. , Greenway Frank L. , Hill James O. , Phinney Stephen D. , Kolotkin Ronette L. , Miller-Kovach Karen , Pi-Sunyer F. Xavier
Published: April 2003

Context

Although commercial weight loss programs provide treatment to millions of clients, their efficacy has not been evaluated in rigorous long-term trials.

Objective

To compare weight loss and health benefits achieved and maintained through self-help weight loss vs with a structured commercial program.

Design and Setting

A 2-year, multicenter randomized clinical trial with clinic visits at 12, 26, 52, 78, and 104 weeks conducted at 6 academic research centers in the United States between January 1998 and January 2001.

Participants

Overweight and obese men (n = 65) and women (n = 358) (body mass index, 27-40) aged 18 to 65 years.

Intervention

Random assignment to either a self-help program (n = 212) consisting of two 20-minute counseling sessions with a nutritionist and provision of self-help resources or to a commercial weight loss program (n = 211) consisting of a food plan, an activity plan, and a cognitive restructuring behavior modification plan, delivered at weekly meetings.

Main Outcome Measures

Weight change was the primary outcome measure. Secondary outcomes included waist circumference, body mass index, blood pressure, serum lipids, glucose, and insulin levels.

Results

At 2 years, 150 participants (71%) in the commercial group and 159 (75%) in the self-help group completed the study. In the intent-to-treat analysis, mean (SD) weight loss of participants in the commercial group was greater than in the self-help group at 1 year (−4.3 [6.1] kg vs −1.3 [6.1] kg, respectively; P<.001) and at 2 years (−2.9 [6.5] kg vs −0.2 [6.5] kg, respectively; P<.001). Waist circumference (P = .003) and body mass index (P<.001) decreased more in the commercial group. Changes in blood pressure, lipids, glucose, and insulin levels were related to changes in weight in both groups, but between-group differences in biological parameters were mainly nonsignificant by year 2.

Conclusion

The structured commercial weight loss program provided modest weight loss but more than self-help over a 2-year period.
Effect of Weight Loss and Lifestyle Changes on Vascular Inflammatory Markers in Obese Women
Authors: Esposito Katherine , Pontillo Alessandro , Di Palo Carmen , Giugliano Giovanni , Masella Mariangela , Marfella Raffaele , Giugliano Dario
Published: April 2003

Context

Obesity is an independent risk factor for cardiovascular disease, which may be mediated by increased secretion of proinflammatory cytokines by adipose tissue.

Objective

To determine the effect of a program of changes in lifestyle designed to obtain a sustained reduction of body weight on markers of systemic vascular inflammation and insulin resistance.

Design and Setting

Randomized single-blind trial conducted from February 1999 to February 2002 at a university hospital in Italy.

Patients

One hundred twenty premenopausal obese women (body mass index ≥30) aged 20 to 46 years without diabetes, hypertension, or hyperlipidemia.

Interventions

The 60 women randomly assigned to the intervention group received detailed advice about how to achieve a reduction of weight of 10% or more through a low-energy Mediterranean-style diet and increased physical activity. The control group (n = 60) was given general information about healthy food choices and exercise.

Main Outcome Measures

Lipid and glucose intake; blood pressure; homeostatic model assessment of insulin sensitivity; and circulating levels of interleukin 6 (IL-6), interleukin 18 (IL-18), C-reactive protein (CRP), and adiponectin.

Results

After 2 years, women in the intervention group consumed more foods rich in complex carbohydrates (9% corrected difference; P<.001), monounsaturated fat (2%; P = .009), and fiber (7 g/d; P<.001); had a lower ratio of omega-6 to omega-3 fatty acids (−5; P<.001); and had lower energy (−310 kcal/d; P<.001), saturated fat (−3.5%; P = .007), and cholesterol intake (−92 mg/d; P<.001) than controls. Body mass index decreased more in the intervention group than in controls (−4.2; P<.001), as did serum concentrations of IL-6 (−1.1 pg/mL; P = .009), IL-18 (−57 pg/mL; P = .02), and CRP (−1.6 mg/L; P = .008), while adiponectin levels increased significantly (2.2 µg/mL; P = .01). In multivariate analyses, changes in free fatty acids (P = .008), IL-6 (P = .02), and adiponectin (P = .007) levels were independently associated with changes in insulin sensitivity.

Conclusion

In this study, a multidisciplinary program aimed to reduce body weight in obese women through lifestyle changes was associated with a reduction in markers of vascular inflammation and insulin resistance.
Behavior Therapy and Sibutramine for the Treatment of Adolescent Obesity
Authors: Berkowitz Robert I. , Wadden Thomas A. , Tershakovec Andrew M. , Cronquist Joanna L.
Published: April 2003

Context

Adolescent obesity is becoming a national public health problem. Weight-loss medications including sibutramine facilitate weight control in adults and could be used with obese adolescents in combination with behavior therapy (BT).

Objective

To examine whether increased weight loss in obese adolescents is induced when sibutramine is added to a family-based, behavioral weight control program.

Design, Setting, and Participants

Randomized, double-blind, placebo-controlled trial consisting of 82 adolescents aged 13 to 17 years with a body mass index (BMI) of 32 to 44 conducted from March 1999 to August 2002 at a university-based clinic for 6 months, followed by open-label treatment during months 7 to 12.

Interventions

For the first 6 months, participants received either BT and sibutramine or BT and placebo. From months 7 to 12, all participants received sibutramine in open-label treatment.

Main Outcome Measures

Percentage change in BMI; systolic and diastolic blood pressure and pulse; and hunger.

Results

In intention-to-treat analysis at month 6, participants in the BT and sibutramine group lost a mean (SD) of 7.8 kg (6.3 kg) and had an 8.5% (6.8%) reduction in BMI, which was significantly more than weight loss of 3.2 kg (6.1 kg) and reduction in BMI of 4.0% (5.4%) in the BT and placebo group. Significantly greater reductions in hunger (P = .002) also were reported by participants who received BT and sibutramine. From months 7 to 12, adolescents initially treated with sibutramine gained 0.8 kg (10.5 kg) with continued use of the medication, whereas those who switched from placebo to sibutramine lost an additional 1.3 kg (5.4 kg). Medication dose was reduced (n = 23) or discontinued (n = 10) to manage increases in blood pressure, pulse rate, or other symptoms.

Conclusions

The addition of sibutramine to a comprehensive behavioral program induced significantly more weight loss than did BT and placebo. Until more extensive safety and efficacy data are available, medications for weight loss should be used only on an experimental basis in adolescents and children.
Health-Related Quality of Life of Severely Obese Children and Adolescents
Authors: Schwimmer Jeffrey B. , Burwinkle Tasha M. , Varni James W.
Published: April 2003

Context

One in 7 US children and adolescents is obese, yet little is known about their health-related quality of life (QOL).

Objective

To examine the health-related QOL of obese children and adolescents compared with children and adolescents who are healthy or those diagnosed as having cancer.

Design, Setting, and Participants

Cross-sectional study of 106 children and adolescents (57 males) between the ages of 5 and 18 years (mean [SD], 12.1 [3] years), who had been referred to an academic children's hospital for evaluation of obesity between January and June 2002. Children and adolescents had a mean (SD) body mass index (BMI) of 34.7 (9.3) and BMI z score of 2.6 (0.5).

Main Outcome Measures

Child self-report and parent proxy report using a pediatric QOL inventory generic core scale (range, 0-100). The inventory was administered by an interviewer for children aged 5 through 7 years. Scores were compared with previously published scores for healthy children and adolescents and children and adolescents diagnosed as having cancer.

Results

Compared with healthy children and adolescents, obese children and adolescents reported significantly (P<.001) lower health-related QOL in all domains (mean [SD] total score, 67 [16.3] for obese children and adolescents; 83 [14.8] for healthy children and adolescents). Obese children and adolescents were more likely to have impaired health-related QOL than healthy children and adolescents (odds ratio [OR], 5.5; 95% confidence interval [CI], 3.4-8.7) and were similar to children and adolescents diagnosed as having cancer (OR, 1.3; 95% CI, 0.8-2.3). Children and adolescents with obstructive sleep apnea reported a significantly lower health-related QOL total score (mean [SD], 53.8 [13.3]) than obese children and adolescents without obstructive sleep apnea (mean [SD], 67.9 [16.2]). For parent proxy report, the child or adolescent's BMI z score was significantly inversely correlated with total score (r = −0.246; P = .01), physical functioning (r = −0.263; P<.01), social functioning (r = −0.347; P<.001), and psychosocial functioning (r = −0.209; P = .03).

Conclusions

Severely obese children and adolescents have lower health-related QOL than children and adolescents who are healthy and similar QOL as those diagnosed as having cancer. Physicians, parents, and teachers need to be informed of the risk for impaired health-related QOL among obese children and adolescents to target interventions that could enhance health outcomes.
Zonisamide for Weight Loss in Obese Adults
Authors: Gadde Kishore M. , Franciscy Deborah M. , Wagner H. Ryan , Krishnan K. Ranga R.
Published: April 2003

Context

Zonisamide is a marketed antiepileptic drug that has serotonergic and dopaminergic activity in addition to blockade of sodium and calcium channels. Weight loss was an adverse effect associated with zonisamide treatment in epilepsy clinical trials.

Objective

To evaluate the efficacy of zonisamide for weight loss in obese adults.

Design and Setting

Sixteen-week randomized, double-blind, placebo-controlled trial with an optional single-blind extension of the same treatment for another 16 weeks, conducted at Duke University Medical Center from March 2001 to March 2002.

Participants

Fifty-five (92%) women and 5 (8%) men (mean [SE] body mass index, 36.3 [0.5]; mean age, 37.0 (1.0) years).

Interventions

Patients were randomly assigned to receive zonisamide (n = 30) or placebo (n = 30). All participants were prescribed a balanced hypocaloric diet (500 kcal/d deficit) and compliance was monitored with self-rated food diaries. Zonisamide therapy was started at 100 mg/d orally, with gradual increase to 400 mg/d and further increase to 600 mg/d for patients losing less than 5% of body weight at the end of 12 weeks. Placebo dosing was identical.

Main Outcome Measure

Change in body weight.

Results

Of the 60 randomized patients, 51 completed the 16-week acute phase. In an intent-to-treat analysis using the available data for all randomized participants with the last observation carried forward, the zonisamide group lost more body weight than the placebo group (mean [SE], 5.9 [0.8] kg [6.0% loss] vs 0.9 [0.4] kg [1.0% loss]; t = 5.5; P<.001) during the 16-week period. A longitudinal mixed-model regression for weight change controlling for age, race, sex, body mass index, and percent body fat estimated that zonisamide treatment over the 16-week study duration was associated with significantly greater weight loss than was placebo (t = 6.4; P<.001). Seventeen (57%) of 30 in the zonisamide group and 3 (10%) of 30 in the placebo group lost at least 5% of body weight (P<.001) by week 16. Of the 37 participants who entered the extension phase, 36 completed week 32. The zonisamide group (n = 19) had a mean weight loss of 9.2 kg (1.7 kg) (9.4% loss) at week 32 compared with 1.5 kg (0.7 kg) (1.8% loss) for the placebo group (n = 17) (t = 4.0; P<.001). Zonisamide was tolerated well, with few adverse effects.

Conclusion

In this short-term, preliminary trial, zonisamide and hypocaloric diet resulted in more weight loss than placebo and hypocaloric diet in the treatment of obesity.
Recombinant Variant of Ciliary Neurotrophic Factor for Weight Loss in Obese Adults
Authors: Ettinger Mark P. , Littlejohn Thomas W. , Schwartz Sherwyn L. , Weiss Stuart R. , McIlwain Harris H. , Heymsfield Steven B. , Bray George A. , Roberts William G. , Heyman Eugene R. , Stambler Nancy , Heshka Stanley , Vicary Catherine , Guler Hans-Peter
Published: April 2003

Context

Obese individuals tend to resist the weight-regulating effects of exogenously administered leptin. A genetically engineered recombinant human variant ciliary neurotrophic factor (rhvCNTF) that signals through leptinlike pathways in the hypothalamus has been shown to bypass leptin resistance in animal models of obesity.

Objective

To identify a safe and well-tolerated dose of rhvCNTF that causes weight loss in obese adults.

Design, Setting, and Patients

Twelve-week, double-blind, randomized, parallel-group, dose-ranging, multicenter clinical trial conducted at 2 university obesity clinics and at 5 independent clinical research clinics from March 2000 to August 2001, and including 173 nondiabetic obese adults, 82.6% of whom were women, with a mean (SD) body mass index of 41.1 (4.1).

Interventions

Patients were randomly assigned to receive daily for 12 weeks subcutaneous injections of placebo (n = 32) or 0.3 µg/kg (n = 32), 1.0 µg/kg (n = 38), or 2.0 µg/kg (n = 33) of rhvCNTF. Another group received 1.0 µg/kg for 8 weeks and placebo for 4 weeks (n = 38), but they were not included in the primary analysis. All participants received instructions for a reduced-calorie diet (World Health Organization formula minus 500 kcal/d).

Main Outcome Measures

Change in weight during the 12-week double-blind treatment period and proportion of patients who achieved a weight loss of at least 5%.

Results

Of the 173 randomized patients, 123 (71%) completed the double-blind dosing period. Mean (SEM) changes in kilograms from baseline body weights were 0.1 (0.6) for placebo and −1.5 (0.6) for the 0.3, −4.1 (0.6) for the 1.0, and –3.4 (0.7) for the 2.0 µg/kg of rhvCNTF dosage groups (P<.001, test for trend). Two patients (8.7%) in the placebo and 2 (8.3%) in the 0.3-µg/kg, 8 (29.6%) in the 1.0-µg/kg, and 5 (26%) in the 2.0-µg/kg treatment groups achieved a weight loss of at least 5%. Recombinant human variant CNTF was generally well tolerated although adverse events occurred in 75% of patients receiving placebo and 78% to 93% of patients receiving rhvCNTF, in a dose-related fashion, with mild injection site reactions as the most frequently reported adverse event.

Conclusions

In this initial, dose-ranging, 12-week study, treatment with rhvCNTF resulted in more weight loss than placebo. These preliminary findings require confirmation in large prospective clinical trials.
Effects of Internet Behavioral Counseling on Weight Loss in Adults at Risk for Type 2 Diabetes
Authors: Tate Deborah F. , Jackvony Elizabeth H. , Wing Rena R.
Published: April 2003

Context

Weight loss programs on the Internet appear promising for short-term weight loss but have not been studied for weight loss in individuals at risk of type 2 diabetes; thus, the longer-term efficacy is unknown.

Objective

To compare the effects of an Internet weight loss program alone vs with the addition of behavioral counseling via e-mail provided for 1 year to individuals at risk of type 2 diabetes.

Design, Setting, and Participants

A single-center randomized controlled trial conducted from September 2001 to September 2002 in Providence, RI, of 92 overweight adults whose mean (SD) age was 48.5 (9.4) years and body mass index, 33.1 (3.8).

Interventions

Participants were randomized to a basic Internet (n = 46) or to an Internet plus behavioral e-counseling program (n = 46). Both groups received 1 face-to-face counseling session and the same core Internet programs and were instructed to submit weekly weights. Participants in e-counseling submitted calorie and exercise information and received weekly e-mail behavioral counseling and feedback from a counselor.

Main Outcome Measures

Measured weight and waist circumference at 0 and 12 months.

Results

Intent-to-treat analyses showed the behavioral e-counseling group lost more mean (SD) weight at 12 months than the basic Internet group (−4.4 [6.2] vs −2.0 [5.7] kg; P = .04), and had greater decreases in percentage of initial body weight (4.8% vs 2.2%; P = .03), body mass index (−1.6 [2.2] vs −0.8 [2.1]; P = .03), and waist circumference (−7.2 [7.5] vs −4.4 [5.7] cm; P = .05).

Conclusion

Adding e-mail counseling to a basic Internet weight loss intervention program significantly improved weight loss in adults at risk of diabetes.
Efficacy and Safety of Low-Carbohydrate Diets
Authors: Bravata Dena M. , Sanders Lisa , Huang Jane , Krumholz Harlan M. , Olkin Ingram , Gardner Christopher D. , Bravata Dawn M.
Published: April 2003

Context

Low-carbohydrate diets have been popularized without detailed evidence of their efficacy or safety. The literature has no clear consensus as to what amount of carbohydrates per day constitutes a low-carbohydrate diet.

Objective

To evaluate changes in weight, serum lipids, fasting serum glucose, and fasting serum insulin levels, and blood pressure among adults using low-carbohydrate diets in the outpatient setting.

Data Sources

We performed MEDLINE and bibliographic searches for English-language studies published between January 1, 1966, and February 15, 2003, with key words such as low carbohydrate, ketogenic, and diet.

Study Selection

We included articles describing adult, outpatient recipients of low-carbohydrate diets of 4 days or more in duration and 500 kcal/d or more, and which reported both carbohydrate content and total calories consumed. Literature searches identified 2609 potentially relevant articles of low-carbohydrate diets. We included 107 articles describing 94 dietary interventions reporting data for 3268 participants; 663 participants received diets of 60 g/d or less of carbohydrates—of whom only 71 received 20 g/d or less of carbohydrates. Study variables (eg, number of participants, design of dietary evaluation), participant variables (eg, age, sex, baseline weight, fasting serum glucose level), diet variables (eg, carbohydrate content, caloric content, duration) were abstracted from each study.

Data Extraction

Two authors independently reviewed articles meeting inclusion criteria and abstracted data onto pretested abstraction forms.

Data Synthesis

The included studies were highly heterogeneous with respect to design, carbohydrate content (range, 0-901 g/d), total caloric content (range, 525-4629 kcal/d), diet duration (range, 4-365 days), and participant characteristics (eg, baseline weight range, 57-217 kg). No study evaluated diets of 60 g/d or less of carbohydrates in participants with a mean age older than 53.1 years. Only 5 studies (nonrandomized and no comparison groups) evaluated these diets for more than 90 days. Among obese patients, weight loss was associated with longer diet duration (P = .002), restriction of calorie intake (P = .03), but not with reduced carbohydrate content (P = .90). Low-carbohydrate diets had no significant adverse effect on serum lipid, fasting serum glucose, and fasting serum insulin levels, or blood pressure.

Conclusions

There is insufficient evidence to make recommendations for or against the use of low-carbohydrate diets, particularly among participants older than age 50 years, for use longer than 90 days, or for diets of 20 g/d or less of carbohydrates. Among the published studies, participant weight loss while using low-carbohydrate diets was principally associated with decreased caloric intake and increased diet duration but not with reduced carbohydrate content.
The effect of a prior cognitive interview on children's acceptance of misinformation
Authors: Holliday Robyn E.
Published: April 2003

This research examined whether a Cognitive interview facilitates correct recall in children aged 4 to 5 and 9 to 10 years, and whether a Cognitive interview given before post‐event misinformation reduces children's reporting of suggestions on subsequent memory tests. Children were presented with an event followed the next day by a Cognitive or a Memorandum interview. Children were then read a post‐event summary containing misleading suggestions. The next day all children were given both standard test and modified forced‐choice cued‐recall tests. The free recall phase of the Cognitive interview elicited the greatest number of correct details. Age differences were found such that 9‐ to 10‐year‐old children's reports were more accurate and more complete than those of the 4‐ to 5‐year‐olds. More correct person, action and object details were reported in a Cognitive interview. Misinformation effects were found in both age groups on the standard test whereas on the modified test such an effect was only found in the 4‐ to 5‐year‐olds. Children's reporting of suggestions was unaffected by prior interview. Copyright © 2003 John Wiley & Sons, Ltd.
Mental reinstatement of the misinformation context and the misinformation effect in children and adults
Authors: Roebers Claudia M. , McConkey Kevin M.
Published: April 2003

The present study investigated the effects of mental reinstatement of the context in which misleading information about an event was presented on later recognition memory for the event. Five‐year‐olds, 7‐year‐olds and adults were shown a short video depicting a children's adventure and were asked a set of misleading questions to introduce misinformation one week later. Before the recognition memory test was administered another week later, half of the participants were given instructions to mentally reinstate the context of the misleading interview. Memory was assessed with a set of forced‐choice recognition questions once in the misleading interview context and for the children a second time at home one week later. When participants were instructed to mentally reinstate the context of the misleading interview prior to the recognition test, false memory reports occurred more often for adults than for children and had a stronger impact on peripheral information than on central information for both 7‐year‐olds and adults. When 5‐ and 7‐year‐olds were tested at home, false memory reports decreased. Thus, reinstating the context of an interview introducing misinformation can reduce the accuracy of memory reports; the context dependence of both accurate and inaccurate memory reports in children and adults is discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Surface Functionalization of Thermoplastic Polymers for the Fabrication of Microfluidic Devices by Photoinitiated Grafting
Authors: Rohr T. , Ogletree D.F. , Svec F. , Fréchet J.M.J.
Published: April 2003

Photografting has been used for the surface modification of a wide range of commercial commodity polymers such as poly‐ styrene, poly(methyl methacrylate), poly(dimethyl siloxane), polycarbonate, Parylene C, polypropylene, cyclic olefin copolymer, and hydrogenated polystyrene that are useful substrate materials for the fabrication of microfluidic chips. Since the chain propagation is initiated after UV light‐activated abstraction of a hydrogen atom from the surface of channels within the materials, their permeability for UV light was tested and polyolefins were found to be the best candidates. A number of monomers with a variety of functional groups such as perfluorinated, hydrophobic, hydrophilic, reactive, acidic, basic, and zwitterionic have been successfully grafted from the surface of selected substrates, and the grafting efficiency determined using X‐ray photoemission spectroscopy. Layered surface structures were prepared by consecutive grafting of different monomers. Our approach also enables photolithographic patterning of surfaces and specific functionalization of confined areas within the microchannel.
Reactive Ion Etching of Cylindrical Polyferrocenylsilane Block Copolymer Micelles: Fabrication of Ceramic Nanolines on Semiconducting Substrates
Authors: Cao L. , Massey J.A. , Winnik M.A. , Manners I. , Riethmüller S. , Banhart F. , Spatz J.P. , Möller M.
Published: April 2003

The diblock copolymers, poly(isoprene‐block‐ferrocenyldimethylsilane) (PI‐b‐PFDMS) and poly(ferrocenyldimethylsilane‐block‐dimethylsiloxane) (PFDMS‐b‐PDMS), form cylindrical micelles with an organometallic polyferrocenylsilane core in a solvent of hexanes. These cylindrical micelles were deposited onto a Si substrate from solution by either spin or dip coating, and upon reactive ion etching, continuous ceramic nanolines with lengths of micrometers and widths as small as 8 nm were created. The nanolines were characterized by scanning force microscopy (SFM) and transmission electron microscopy (TEM), and were shown to contain Fe, Si, and O from X‐ray photoelectron spectroscopy (XPS) studies. The widths of the nanolines could be varied from ca. 8 to 30 nm, depending on the composition of the corona (PI or PDMS). The oriented deposition of these cylindrical micelles can be achieved along pre‐patterned grooves on a resist film using capillary forces. Following treatment with hydrogen or oxygen plasma, oriented ceramic nanolines can be fabricated. The approach reported here represents a relatively simple method to create ceramic nanolines with large aspect ratio on semiconducting substrates.
Stabilization of Isolated Hydrous Amorphous and Tetragonal Zirconia Nanoparticles Through the Formation of a Passivating Alumina Shell
Authors: Kirsch B.L. , Tolbert S.H.
Published: April 2003

In this work, we explore the high‐temperature phase stability of isolated, alumina‐coated zirconia nanocrystals with a goal of understanding how interfacial energy affects phase stability. Isolated tetragonal and hydrous amorphous zirconia colloids were synthesized and coated with alumina through the hydrolysis of aluminum isopropoxide. Alumina‐coated samples exhibited phase behavior that was markedly different from that of the uncoated analogs. Uncoated tetragonal particles transformed to the monoclinic phase at 1100 °C while alumina‐coated tetragonal particles did not transform until 1400 °C. Uncoated hydrous amorphous particles crystallized to the tetragonal phase after heating at 600 °C and transformed to the monoclinic phase after heating at 800 °C. Alumina‐coated hydrous amorphous particles crystallized only after heating at 1050 °C, and transformed to the monoclinic phase after heating at 1400 °C. Differences in phase behavior are postulated to depend on the zirconia–alumina interface, which must be disrupted before zirconia particles can fuse and facilitate the tetragonal‐to‐monoclinic phase transition. By coating the nanocrystals with a thin alumina shell and studying the resultant phase stability, we explore the effect of reproducibly modified interfacial chemistry on phase behavior in nanoscale ceramic composites.
Fast and High‐Contrast Electro‐optical Switching of Liquid‐Crystalline Physical Gels: Formation of Oriented Microphase‐Separated Structures
Authors: Mizoshita N. , Hanabusa K. , Kato T.
Published: April 2003

Fast and high‐contrast responses with low driving voltages in twisted nematic (TN) cells are achieved for anisotropically oriented structures of liquid‐crystalline physical gels. They are prepared by hydrogen‐bonded aggregation of an L‐lysine‐based gelator in nematic liquid crystals. When the mixtures of the nematic liquid crystals and the gelator are prepared in TN cells, fibrous aggregates of the gelator align along the twisted‐nematic orientation of the liquid crystal, forming oriented phase‐separated structures.