bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational Nanomechanics of Graphene Membranes
Authors: Perriot Romain , Gu Xiang , Oleynik Ivan I. 
Published: June 2009

AbstractMolecular Dynamics (MD) simulations of nanoindentation on graphene membranes were performed. The 2-d Young's modulus of the graphene monolayer was determined as 243 ± 18 N/m and the breaking strength as 41 ± 3 N/m. These values agree reasonably well with recent experimental results [1]. In addition, the simulations allowed us to examine the atomic-scale dynamics of membrane breaking during the nanoindentation, involving formation of an increasing number of lattice defects until membrane is completely broken. The onset of defect appearance allowed us to determine the true elastic limit of graphene and the corresponding yield strength 29 ± 1 N/m which was not accessible experimentally. The defects consist of vacancies and Stone-Wales type defects. Long stable linear chains ofspbonded carbon atoms (carbynes) were observed under the indenter at the advanced stages of indentation. The dynamics of fracture propagation is governed by the shear stresses developed in the sample.
Shell repair in the clam Ruditapes philippinarum, affected by the Brown Ring Disease (BRD): a biochemical and serological study
Authors: Trinkler Nolwenn , Marin Frederic , Guichard Nathalie , Labonne Maylis , Bardeau Jean-François , Paillard Christine 
Published: June 2009

AbstractFor more than two decades, the edible clam Ruditapes philippinarum has been affected by the Brown Ring Disease (BRD), a bacterial infection characterized by the formation of a brown organic deposit in the internal side of the valves. Although this infection is often lethal, in some cases specimens can overcome it by remineralizing over the organic deposit. The goal of the present study is to compare biochemically and immunologically the shell matrices of repaired and healthy zones. Our data suggest that the repair zones exhibit certain variability, which would be the direct consequence of a modification of the secretory regime of calcifying tissues responsible of the repair process.
The Effect of Cellular Architecture on the Ductility and Strength of Metal Foams
Authors: Mangipudi K. R. , Onck Patrick R 
Published: June 2009

AbstractA multiscale finite element model has been developed to study the fracture behaviour of two-dimensional random Voronoi structures. The influence of materials parameters and cellular architecture on the damage initiation and accumulation has been analyzed. The effect of the solid material’s strain hardening, relative density and architectural randomness on the ductility and fracture strength of the cellular solid are investigated. The results suggest materials-design directions in which the heat treatment, the solid material properties, its microstructure and the cellular architecture can be tuned for an optimized performance of cellular materials.
Acoustic Properties of Organic/Inorganic Composite Aerogels
Authors: Dong Winny , Faltens Tanya , Pantell Michael , Simon Diana , Thompson Travis , Dong Wayland 
Published: June 2009

AbstractComposite aerogels (with varying concentrations of silica and poly-dimethylsiloxane) were developed and their acoustic absorption coefficient as a function of composition and average pores size have been measured. The polydimethylsiloxane modified the ceramic structure of the silica aerogels, decreasing the material’s rigidity while maintaining the high porosity of the aerogel structure. The composite aerogels were found to exhibit different modes
of acoustic absorption than that of typical porous absorbers such as fiberglass. At some frequencies, the composite aerogels had 40% higher absorption than that of commercial fiberglass. Physical data show that these materials have a large surface area (> 400 m2/g) and varying pore sizes (d ˜ 5 - 20 nm).
Nanoparticle Based Multilayers as Multifunctional Optical Coatings
Authors: Colodrero Silvia , Calvo Mauricio E. , Sobrado Olalla Sánchez , Míguez Hernán 
Published: June 2009

AbstractHerein we introduce nanoparticle based periodic multilayers as base materials to create different types of multifunctional coatings that combine optical, mechanical and diffusion properties. The technological potential of these versatile materials is demonstrated by showing applications in the fields of sensing and photovoltaic materials. Due to the porous nature of such structures, liquids and gases can infiltrate or condensate, respectively within the interstices, causing a variation of the refractive index (R.I.)of the layers. This gives rise to clear but gradual changes of the optical responses, either when liquids or the partial pressure of vapors are infiltrated in the structure. Also, photoconducting Bragg mirrors can be built by precise control of the spatial variation of the R.I. of the layers in a pure TiO2 multilayer. Rationally placed within a Dye Sensitized Solar Cell (DSSC), that gives rise to a significant enhancement of the solar to electric power conversion efficiency through the amplification of sunlight absorption. Direct observation of both optical absorption and photocurrent resonances can be seen.
Dynamic constitutional hybrid materials-toward adaptive self-organized devices
Authors: Barboiu Mihail , Cazacu Adinela , Mihai Simona , Legrand Yves-Marie , van der Lee Arie 
Published: June 2009

AbstractDynamic constitutional hybrid materials in which the functional self-organized macrocycles are reversibly connected with the inorganic silica mesopores through hydrophobic non-covalent interactions. Supramolecular columnar self-organized architectures confined within scaffolding hydrophobic silica mesopores can be structurally determined by using X-ray diffraction techniques.
Effect of Implant Design on Initial Stability of Tapered Implants
Authors: Chong Linus , Khocht Ahmed , Suzuki Jon B. , Gaughan John 
Published: June 2009

Abstract
Implant design is one of the parameters for achieving successful primary stability. This study aims to examine the effect of a self-tapping blades implant design on initial stability in tapered implants. Polyurethane blocks of different densities were used to simulate different bone densities. The two different implant designs included one with self-tapping blades and one without self-tapping blades. Implants were placed at 3 different depths: apical third, middle third, and fully inserted at 3 different densities of polyurethane blocks. A resonance frequency (RF) analyzer was then used to measure stability of the implants. Repeated-measures analysis of variance was used to examine the effect of implant design, insertion depth, and block density on RF. Analysis of covariance was used to examine the strength of association between RF and the aforementioned factors. In both medium-density (P = .017) and high-density (P = .002) blocks, fully inserted non-self-tapping implants showed higher initial stability than self-tapping implants. No differences were noted between the 2 implant designs that were not fully inserted. The highest strength of association was with insertion depth (standardized beta [std β] = −0.60, P = .0001), followed by block density (std β = −0.15, P = .0002). Implant design showed a weak association (std β = −0.07, P = .09). In conclusion, fully inserted implants without self-tapping blades have higher initial stability than implants with self-tapping blades. However, the association strength between implant design and initial stability is less relevant than other factors, such as insertion depth and block density. Thus, if bone quality and quantity are optimal, they may compensate for design inadequacy.
Immediate Placement and Temporization of Implants: Three- to Five-year Retrospective Results
Authors: Avvanzo Pierluigi , Ciavarella Domenico , Avvanzo Andrea , Giannone Nicola , Carella Mauro , Lo Muzio Lorenzo 
Published: June 2009

Abstract
The immediate placement of dental implants in esthetic areas is a primary challenge for modern implantology. The underlying treatment goal is to preserve the natural periodontal architecture; in recent years, however, a concurrent goal has been to reduce the period between implant placement in the fresh extraction socket and delivery of the definitive restoration, but adequate long-term data are still lacking on the efficacy of this technique. A 3- to 5-year retrospective analysis of 282 dental implants immediately placed into extraction sockets, and temporized with nonoccluding provisional prostheses has been undertaken. All recorded outcomes and complications, as well as a proposed protocol for management of immediate function, are discussed.
Political Economy of US States and Rates of Fatal Occupational Injury
Authors: Loomis Dana , Schulman Michael D. , Bailer A. John , Stainback Kevin , Wheeler Matthew , Richardson David B. , Marshall Stephen W. 
Published: June 2009

Objectives. We investigated the extent to which the political economy of US states, including the relative power of organized labor, predicts rates of fatal occupational injury. Methods. We described states’ political economies with 6 contextual variables measuring social and political conditions: “right-to-work” laws, union membership density, labor grievance rates, state government debt, unemployment rates, and social wage payments. We obtained data on fatal occupational injuries from the National Traumatic Occupational Fatality surveillance system and population data from the US national census. We used Poisson regression methods to analyze relationships for the years 1980 and 1995. Results. States differed notably with respect to political–economic characteristics and occupational fatality rates, although these characteristics were more homogeneous within rather than between regions. Industry and workforce composition contributed significantly to differences in state injury rates, but political–economic characteristics of states were also significantly associated with injury rates, after adjustment accounting for those factors. Conclusions. Higher rates of fatal occupational injury were associated with a state policy climate favoring business over labor, with distinct regional clustering of such state policies in the South and Northeast.
Real-Time Public Health Surveillance for Emergency Preparedness
Authors: Chretien Jean-Paul , Tomich Nancy E. , Gaydos Joel C. , Kelley Patrick W. 
Published: June 2009

Public health agencies conduct surveillance to identify and prioritize health issues and evaluate interventions. Recently, natural and deliberate epidemics have motivated supplementary approaches to traditional surveillance methods based on physician and laboratory reporting. Fueled initially by post–September 11, 2001, bioterrorism-related funding, and more recently used for detecting natural outbreaks, these systems, many of which are called “syndromic” systems because they focus on syndromes recorded before the diagnosis, capture real-time health data and scan for anomalies suggesting an outbreak. Although these systems as typically implemented have often proven unreliable for detecting natural and simulated epidemics, real-time health-related data hold promise for public health. If redesigned to reliably perform beyond outbreak detection, syndromic systems could demonstrate unprecedented capabilities in responding to public health emergencies.
Gender-Specific Correlates of Incarceration Among Marginally Housed Individuals in San Francisco
Authors: Weiser Sheri D. , Neilands Torsten B. , Comfort Megan L. , Dilworth Samantha E. , Cohen Jennifer , Tulsky Jacqueline P. , Riley Elise D. 
Published: June 2009

Objectives. We assessed how different patterns of housing instability affect incarceration and whether correlates of incarceration are gender specific. Methods. We used multivariate logistic regression to assess associations between patterns of housing instability and recent jail stays among a reproducible sample of 1175 marginally housed adults in San Francisco, California. Results. Over the previous year, 71% of men and 21% of women in the sample reported jail stays. Among women, long-term single-room occupancy hotel stays ( > 90 days) were protective for incarceration. Stays in the street were associated with incarceration among both genders, but among men, short-term (i.e., ≤ 90 days) street stays were associated with the highest odds of incarceration, and among women, long-term street stays were most correlated with incarceration. Sex trade increased the odds of incarceration among men only; recent drug use was associated with incarceration among both genders. Conclusions. Correlates of incarceration differed by gender, and patterns of housing instability differentially affected incarceration for men and women. Policies to improve housing options and drug treatment for the urban poor are critical to breaking the cycle of incarceration and homelessness and improving health outcomes.
Influences of Cross-Border Mobility on Tuberculosis Diagnoses and Treatment Interruption Among Injection Drug Users in Tijuana, Mexico
Authors: Deiss Robert , Garfein Richard S. , Lozada Remedios , Burgos Jose Luis , Brouwer Kimberly C. , Moser Kathleen S. , Zuniga Maria Luisa , Rodwell Timothy C. , Ojeda Victoria D. , Strathdee Steffanie A. 
Published: June 2009

Objectives. We sought to identify correlates of reported lifetime diagnoses of TB among injection drug users in the border city of Tijuana, Mexico. Methods. Injection drug users in Tijuana were recruited into a prospective cohort study during 2006 and 2007. We used weighted multivariate logistic regression to identify correlates of TB diagnoses. Results. Of the 1056 participants, 103 (9.8%) reported a history of TB, among whom 93% received anti-TB medication and 80% were diagnosed in the United States. Treatment was prematurely halted among 8% of patients; deportation from the United States was the cause of half of these treatment interruptions. History of travel to (odds ratio [OR] = 6.44; 95% confidence interval [CI] = 1.53, 27.20) or deportation from (OR = 1.83; 95% CI = 1.07, 3.12) the United States and incarceration (OR = 2.20; 95% CI = 1.06, 4.58) were independently associated with a reported lifetime diagnosis of TB. Conclusions. Mobility and migration are important factors in identifying and treating TB patients diagnosed in the US–Mexico border region. Strengthening capacity on both sides of the border to identify, monitor, and treat TB is a priority.
Pathways to and From Homelessness and Associated Psychosocial Outcomes Among Adolescents Leaving the Foster Care System
Authors: Fowler Patrick J. , Toro Paul A. , Miles Bart W. 
Published: June 2009

Objectives. We evaluated the prevalence and nature of housing problems among adolescents leaving foster care because of their age to provide evidence that can inform public and programmatic policies designed to prevent homelessness. Methods. Housing and psychosocial outcomes in a sample of 265 adolescents who left the foster care system in 2002 and 2003 in a large midwestern metropolitan area were evaluated over a 2-year follow-up period. Analyses focused on identifying latent housing trajectory categories across the first 2 years after participants' exit from foster care. Results. Findings revealed 4 latent housing classifications. Most participants (57%) had experienced stable housing situations since their exit from foster care. Those in the remaining 3 categories endured housing problems, and 20% were chronically homeless during the follow-up period. Housing instability was related to emotional and behavioral problems, physical and sexual victimization, criminal conviction, and high school dropout. Conclusions. Adolescents in foster care are at considerable risk of homelessness. Preventive initiatives can reduce homelessness in this population by implementing improved foster care programming and developing empirically informed interventions targeting foster care adolescents.
Use of a Social and Character Development Program to Prevent Substance Use, Violent Behaviors, and Sexual Activity Among Elementary-School Students in Hawaii
Authors: Beets Michael W. , Flay Brian R. , Vuchinich Samuel , Snyder Frank J. , Acock Alan , Li Kin-Kit , Burns Kate , Washburn Isaac J. , Durlak Joseph 
Published: June 2009

Objectives. We assessed the effectiveness of a 5-year trial of a comprehensive school-based program designed to prevent substance use, violent behaviors, and sexual activity among elementary-school students. Methods. We used a matched-pair, cluster-randomized, controlled design, with 10 intervention schools and 10 control schools. Fifth-graders (N = 1714) self-reported on lifetime substance use, violence, and voluntary sexual activity. Teachers of participant students reported on student (N = 1225) substance use and violence. Results. Two-level random-effects count models (with students nested within schools) indicated that student-reported substance use (rate ratio [RR] = 0.41; 90% confidence interval [CI] = 0.25, 0.66) and violence (RR = 0.42; 90% CI = 0.24, 0.73) were significantly lower for students attending intervention schools. A 2-level random-effects binary model indicated that sexual activity was lower (odds ratio = 0.24; 90% CI = 0.08, 0.66) for intervention students. Teacher reports substantiated the effects seen for student-reported data. Dose-response analyses indicated that students exposed to the program for at least 3 years had significantly lower rates of all negative behaviors. Conclusions. Risk-related behaviors were substantially reduced for students who participated in the program, providing evidence that a comprehensive school-based program can have a strong beneficial effect on student behavior.
Secondhand Smoke in Pennsylvania Casinos: A Study of Nonsmokers' Exposure, Dose, and Risk
Authors: Repace James L. 
Published: June 2009

Objectives. I assessed air pollution, ventilation, and nonsmokers' risk from secondhand smoke (SHS) in Pennsylvania casinos exempted from a statewide smoke-free workplace law. Methods. I measured respirable suspended particles (RSPs), particulate polycyclic aromatic hydrocarbons (PPAHs), and carbon dioxide inside and outside casinos; measured changes in patrons' urine cotinine after casino visits; and assessed SHS impact on workers and patrons, using exposure–response models, air quality standards, and odor and irritation thresholds. Results. PPAH and RSP concentrations in casinos were, on average, 4 and 6 times, respectively, that of outdoor levels despite generous ventilation and low smoking prevalence. SHS infiltrated into nonsmoking gaming areas. Patrons' urine cotinine increased 1.9 ng/mL on average after about 4-hour visits. Conclusions. SHS-induced heart disease and lung cancer will cause an estimated 6 Pennsylvania casino workers' deaths annually per 10 000 at risk, 5-fold the death rate from Pennsylvania mining disasters. Casinos should not be exempt from smoke-free workplace laws.
Prevalence, Characteristics, and Associated Health and Health Care of Family Homelessness Among Fifth-Grade Students
Authors: Coker Tumaini R. , Elliott Marc N. , Kanouse David E. , Grunbaum Jo Anne , Gilliland M. Janice , Tortolero Susan R. , Cuccaro Paula , Schuster Mark A. 
Published: June 2009

Objectives. We describe the lifetime prevalence and associated health-related concerns of family homelessness among fifth-grade students. Methods. We used a population-based, cross-sectional survey of 5147 fifth-grade students in 3 US cities to analyze parent-reported measures of family homelessness, child health status, health care access and use, and emotional, developmental, and behavioral health and child-reported measures of health-related quality of life and exposure to violence. Results. Seven percent of parents reported that they and their child had experienced homelessness (i.e., staying in shelters, cars, or on the street). Black children and children in the poorest families had the highest prevalence of homelessness (11%). In adjusted analyses, most general health measures were similar for children who had and had not been homeless. Children who had ever experienced homelessness were more likely to have an emotional, behavioral, or developmental problem (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.1, 2.6; P = .01), to have received mental health care (OR = 2.2; 95% CI = 1.6, 3.2; P < .001), and to have witnessed serious violence with a knife (OR = 1.6; 95% CI = 1.1, 2.3; P = .007) than were children who were never homeless. Conclusions. Family homelessness affects a substantial minority of fifth-grade children and may have an impact on their emotional, developmental, and behavioral health.
Effects of a Prekindergarten Educational Intervention on Adult Health: 37-Year Follow-Up Results of a Randomized Controlled Trial
Authors: Muennig Peter , Schweinhart Lawrence , Montie Jeanne , Neidell Matthew 
Published: June 2009

Objectives. We used 37 years of follow-up data from a randomized controlled trial to explore the linkage between an early educational intervention and adult health. Methods. We analyzed data from the High/Scope Perry Preschool Program (PPP), an early school-based intervention in which 123 children were randomized to a prekindergarten education group or a control group. In addition to exploring the effects of the program on health behavioral risk factors and health outcomes, we examined the extent to which educational attainment, income, family environment, and health insurance access mediated the relationship between randomization to PPP and behavioral and health outcomes. Results. The PPP led to improvements in educational attainment, health insurance, income, and family environment Improvements in these domains, in turn, lead to improvements in an array of behavioral risk factors and health (P = .01). However, despite these reductions in behavioral risk factors, participants did not exhibit any overall improvement in physical health outcomes by the age of 40 years. Conclusions. Early education reduces health behavioral risk factors by enhancing educational attainment, health insurance coverage, income, and family environments. Further follow-up will be needed to determine the long-term health effects of PPP.
The Limits of Collaboration: A Qualitative Study of Community Ethical Review of Environmental Health Research
Authors: McGrath Moriah McSharry , Fullilove Robert E. , Kaufman Molly Rose , Wallace Rodrick , Fullilove Mindy Thompson 
Published: June 2009

Objectives. We assessed the effectiveness of various systems of community participation in ethical review of environmental health research.Methods. We used situation analysis methods and a global workspace theoretical framework to conduct comparative case studies of 3 research organizations at 1 medical center.Results. We found a general institutional commitment to community review as well as personal commitment from some participants in the process. However, difficulty in communicating across divides of knowledge and privilege created serious gaps in implementation, leaving research vulnerable to validity threats (such as misinterpretation of findings) and communities vulnerable to harm. The methods used in each collaboration solved some, but not all, of the problems that hindered communication.Conclusions. Researchers, community spokespersons, and institutional review boards constitute organizational groups with strong internal ties and highly developed cultures. Few cross-linkages and little knowledge of each other cause significant distortion of information and other forms of miscommunication between groups. Our data suggest that organizations designed to protect human volunteers are in the best position to take the lead in implementing community review.