Characterization of aerosolized particles in effluents from carbon fibre composites incorporating nanomaterials during simultaneous fire and impact.

This work investigates the aerosols emitted from carbon fibre-reinforced epoxy composites (CFC) incorporating nanomaterials (nanoclays and nanotubes), subjected to simultaneous fire and impact, representing an aeroplane or automotive crash. Simultaneous fire and impact tests were performed using a previously described bespoke testing methodology with the capability to collect particles released from the front/back faces of the impacted composites plus the effluents. In this work the methodology has been further developed by connecting the Dekati Low Pressure Impactor (DLPI) and Mini Particle Sampler (MPS) sampling system in the extraction chimney. The aerosols emitted have been characterized using various devices devoted to the analysis of aerosols. The influence of the nanoadditives in the matrix on the number concentration and the size distribution of airborne particles produced, was studied with a cascade impactor in the 5 nm-10 µm range. The morphology of the separated soot fractions was examined by SEM. The measurement of aerodynamic size of particles that can deposit in human respiratory tract indicate that 75% of the soot and particles released from CFC could deposit in the lungs reaching the bronchi region at a minimum. There was however, a minimal difference between the number particle concentrations or particle-size mass distribution of particles from CFC and CFC containing nanoadditives. Moreover, no fibres were found in the effluents.

Contribution to the study of particle resuspension kinetics during thermal degradation of polymers.

Experimental results are reported on the resuspension of particles deposited on polymer samples representative of glove boxes used in the nuclear industry, under thermal degradation. A parametric study was carried out on the effects of heat flux, air flow rate, fuel type and particle size distribution. Small-scale experiments were conducted on 10 cm × 10 cm PolyMethyl MethAcrylate (PMMA) and PolyCarbonate (PC) samples covered with aluminium oxide particles with physical geometric diameters of 0.7 and 3.6 µm. It was observed for both polymer (fuel) samples that heat flux has no effect on the airborne release fraction (ARF), whereas particle size is a significant parameter. In the case of the PMMA sample, ARF values for 0.7 and 3.6 µm diameter particles range from 12.2% (± 6.2%) to 2.1% (± 0.6%), respectively, whereas the respective values for the PC sample range from 3.2% (± 0.8%) to 6.9% (± 3.9%). As the particle diameter increases, a significant decrease in particle release is observed for the PMMA sample, whereas an increase is observed for the PC sample. Furthermore, a peak airborne release rate is observed during the first instants of PMMA exposure to thermal stress. An empirical relationship has been proposed between the duration of this peak release and the external heat flux.

The effect of a feedback signal in a computer mouse on hovering behaviour, productivity, comfort and usability in a field study.

The aim of this study was to determine the effect of a tactile feedback signal on hovering behaviour, productivity, usability and comfort after 1 week of using an experimental mouse. In a randomized controlled trial, a regular computer mouse was compared to a new developed mouse with a tactile, vibrating feedback signal to prevent unnecessary hovering above the computer mouse. According to this study, participants do decrease their hovering behaviour when using a mouse with tactile feedback. Furthermore, the mouse with tactile feedback did not influence productivity. Usability was rated somewhat mixed. The use of a mouse with a tactile vibrating feedback signal seems promising for preventing neck, shoulder and arm complaints. Further research is needed to study long-term effects on (prevention of) neck, shoulder and arm complaints and development of learning effects.

Mentoring Cambodian and Lao health professionals in tobacco control leadership and research skills.

DESIGN: The aim of the programme was to ultimately affect public health practice and policy in the Kingdom of Cambodia and Lao People's Democratic Republic (Lao PDR) by training key health professionals to conduct tobacco control research. SETTING: Encouraged by the World Health Organization's Framework Convention on Tobacco Control, a global partnership formed to build effective leadership to develop and guide national tobacco control agendas. The partners were the Ministries of Health (Cambodia and Lao PDR), non-government organisations (Adventist Development and Relief Agency in Cambodia and Laos) and an academic institution (Loma Linda University, Loma Linda, California, USA). SUBJECTS: 16 health professionals, 10 from Cambodia and 6 from Lao PDR, were selected by local advisory committees to enter a two-year, intensive tobacco research graduate certificate and research training programme. INTERVENTION: We developed a "Global Tobacco Control Methods" (GTCM) 28 unit certificate programme that was offered in five sessions from September 2003 to September 2005 at the National Institute of Public Health, Phnom Penh, Cambodia. As part of their coursework, the 16 trainees actively participated in the development and implementation of two research projects. In the first project, "Healthy Doc Healthy Patient" (HDHP), trainees adapted an existing, self-administered questionnaire designed to assess health practices and beliefs of medical students in Cambodia and Lao PDR. The second project involved the design of a national prevalence of tobacco use and health beliefs study in Cambodia using a multi-stage, cluster sample method. Trainees were sponsored to attend and present at international tobacco control conferences to enhance their awareness of the tobacco epidemic. RESULTS: As of September 2005, 14 trainees (8 from Cambodia and 6 from Lao PDR) completed the courses in the GTCM certificate programme. The HDHP study sampled four medical school classes (years 3, 4, 5 and 6) in both Cambodia (n = 330, 71.1% response rate) and Lao PDR (n = 386, 87.3% response rate). As part of the Cambodian adult tobacco prevalence study in Cambodia, 13,988 adults (ages > or = 18 years) were interviewed from all 22 provinces during the summer of 2005. Over the two years, more than half of the trainees participated substantially in local and regional tobacco control and research activities. Programme challenges included the trainees' limited English language and computer proficiency skills, both of which improved during the two years. CONCLUSIONS: With the successful completion of the certificate programme, the remaining two years of the grant will be used to prepare the trainees for positions of leadership within their Ministries of Health and other agencies to implement effective tobacco control policies based on locally-derived research findings.

Efficacy and safety of bupropion SR for smoking cessation: data from clinical trials and five years of postmarketing experience.

Bupropion SR was introduced for smoking cessation in the US in 1997. This review assesses the efficacy and safety of bupropion SR for treatment of tobacco dependence based on data from clinical trials and five years of postmarketing experience. Through June 2001, there were approximately 32 million patient exposures to bupropion (9 million for smoking cessation) in clinical practice, and more than 8000 patients have been studied in clinical trials for tobacco dependence. In clinical trials, bupropion SR was more effective than placebo at improving initial and long-term abstinence rates and preventing relapse. Bupropion SR is generally well tolerated. The most common adverse event in clinical trials or clinical practice is insomnia, which can also be a symptom of nicotine withdrawal. The two main risks of treatment with bupropion SR are major motor seizure and hypersensitivity reaction. Clinical trials data suggest that the incidence of seizure is approximately 0.1%, and that of serious cases of hypersensitivity approximately 0.12%. Benefit-risk assessment, assuming a 30% one-year quit rate demonstrates that for every 10,000 smokers treated with bupropion SR, 19 lives are saved and 86 cases of smoking-attributed morbidity are averted in a five-year period while the risk of experiencing one of the two potentially serious adverse events during treatment is 0.22%. These data further establish both the efficacy and safety of bupropion SR and its use in preventing the adverse health effects of chronic tobacco use.

Bupropion SR as an aid to smoking cessation in smokers treated previously with bupropion: a randomized placebo-controlled study.

BACKGROUND: Many persons who attempt to quit smoking have made previous unsuccessful attempts to quit with pharmacologic aids. An understanding of the impact of these previous attempts to quit is vital for selecting medications that may be more successful in a future attempt to quit. In particular, the effect of repeated use of bupropion SR (Zyban; INN, amfebutamone) on abstinence rates has not been studied previously. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled study in 450 smokers who had previously used bupropion in a smoking cessation attempt. The study consisted of a screening phase, a 12-week treatment phase, and a follow-up at month 6. Participants made regular clinic visits throughout the treatment phase during which they received brief counseling sessions to encourage abstinence from smoking. The primary end point was continuous abstinence from smoking from weeks 4 through 7. Secondary efficacy end points were examined throughout the treatment phase and at follow-up after 6 months. RESULTS: In participants receiving bupropion SR, 27% (61 of 226) remained abstinent throughout the period from weeks 4 through 7 compared with 5% (11 of 224) of participants receiving placebo (P <.001). Significantly (P <.001) more participants who received bupropion SR during the treatment phase remained continuously abstinent from the start of week 4 through month 6 (27 of 226; 12%) compared with participants who received placebo (5 of 224; 2%). Eleven participants receiving placebo (5%) and 19 participants receiving bupropion SR (8%) stopped taking the study medication because of an adverse event. CONCLUSIONS: Bupropion SR is an effective medication for retreatment of smokers who have used bupropion SR previously.

Processability of cottonseed proteins into biodegradable materials.

The manufacture of biodegradable materials from agricultural sources is a real challenge, because of environmental concerns and the need to make full use of resources. Cottonseed is an important protein source that could be used in nonfood applications, as a substitute for synthetic polymers. For the first time, the viscoelastic behavior of cottonseed protein isolate (CPI), plasticized with glycerol, was characterized in order to determine the temperature range within which cottonseed protein-based materials can be formed by extrusion or thermomolding. Research involved three main techniques: dynamic mechanical analysis to study the alpha protein relaxation associated with glass transition, as a function of plasticization by glycerol; DSC analysis to determine the effect of glycerol content on the protein denaturation and degradation temperatures; and ATG-TG/FTIR to characterize the protein degradation. The results indicated that cottonseed proteins are thermoplastics with a T(g) ranging from 80 to 200 degrees C when the glycerol content varies from 0% to 40% (w/w, dry basis). The proteins' thermal denaturation temperature increased from 141 (without glycerol) to 195 degrees C in the presence of 40% (w/w) glycerol. Protein degradation occurred at 230 degrees C irrespective of glycerol content, with the release of a variety of compounds. Glycerol acts as a plasticizer and thermal stabilizer of the proteins and increases the range of temperatures (80-175 degrees C) at which the material can be processed.

Tobacco dependence curricula in US undergraduate medical education.

CONTEXT: Tobacco use is the leading preventable cause of death in the United States. And yet only 21% of practicing physicians claim they received adequate training to help their patients stop smoking. OBJECTIVE: To assess the content and extent of tobacco education and intervention skills in US medical schools' curricula. DESIGN: A survey with 13 multiple-response items on tobacco education. Survey questions were based on the recommendations of the Agency for Health Care Policy and Research and the National Cancer Institute Expert Panel. The Liaison Committee on Medical Education included 4 of these items in a modified form on the 1997 annual questionnaire. SETTING: One hundred twenty-six US medical schools. PARTICIPANTS: Surveys were obtained from 122 associate deans for medical education (98.6%). MAIN OUTCOME MEASURES: Curriculum content in basic science and clinical science, elective or required clinical experience, hours of instruction, and resource materials. RESULTS: Inclusion of all 6 tobacco curricula content areas recommended by the National Cancer Institute and the Agency for Health Care Policy and Research was higher in basic science (63/115 [54.8%]) than in clinical science (5/115 [4.4%]). Most medical schools (83/120 [69.2%]) did not require clinical training in smoking cessation techniques, while 23.5% (27/115) offered additional experience as an elective course. Thirty-one percent (32/102) of schools averaged less than 1 hour of instruction per year in smoking cessation techniques during the 4 years of medical school. A minority of schools reported 3 or more hours of clinical smoking cessation instruction in the third (14.7%) and fourth (4.9%) years. CONCLUSIONS: A majority of US medical school graduates are not adequately trained to treat nicotine dependence. The major deficit is the lack of smoking cessation instruction and evaluation in the clinical years. A model core tobacco curricula that meets national recommendations should be developed and implemented in all US medical schools.

Non-nicotine pharmacotherapy for smoking cessation.

The selection of a non-nicotine treatment is based on the acceptability of various treatments with smokers, the ability to address the specific neurobiology of nicotine addiction, and the option to provide treatment for co-morbid conditions of nicotine-dependent patients. The search for effective treatments for nicotine dependence has generated a wide variety of non-nicotine approaches based on the neuropharmacologic and sensory basis for tobacco use. The only non-nicotine, FDA-approved medication is bupropion, an amino-ketone agent that is believed to work on the dopaminergic and noradrenergic neurotransmitters involved in perpetuating nicotine dependence. This article reviews other unapproved medications, mechanisms of action, and their effectiveness in clinical trials.

Overcoming barriers to nicotine dependence treatment.

Tobacco dependence is the most overlooked and undertreated preventable cause of chronic disease in the developed world. Three barriers to effective treatment must be overcome: the reluctance of nicotine addicts to seek help; inadequate training of health professionals to treat hard core smokers; and a health care system that does not acknowledge the need for professional treatment of nicotine addiction. Effective physicians are equipped with the knowledge and skills to identify high-risk smokers who need more assistance to quit. All smokers should be engaged in a tailored office intervention based on their needs. Adoption of simple clinical protocols can eliminate the barriers that prevent effective counseling and treatment in the office setting.

Association of the serotonin transporter gene with serum cholesterol levels and heart disease.

In a study of a group of elderly athletes we observed an unexpected association between serum cholesterol levels and the HTTLPR insertion/deletion polymorphism of the promoter region of the serotonin transporter gene (HTT, SLC6A4). As a follow-up we examined the potential association of this polymorphism with cholesterol and triglyceride levels, or heart disease, in two other groups of subjects. We examined the possible association between cholesterol levels and heart disease and genotypes of the HTTLPR insertion/deletion polymorphism of the promoter region of the HTT gene, in three independent study populations ranging from 42 to 90 years of age. For subjects 55 to 70 years of age in Group 1, cholesterol levels were significantly greater in the LS heterozygotes than either LL or SS homozygotes, indicating a heterosis effect (P 70 years of age. While these studies are preliminary and exploratory, they are consistent with a relationship of the HTT gene in cholesterol levels and a risk for heart disease. Replication of these findings in independent, epidemiologically based studies is required.

Iontophoresis of poly-L-lysines: the role of molecular weight?

PURPOSE: (1) To determine the extent of iontophoretic transport as a function of molecular weight (MW) of the penetrant; and (2) to visually and quantitatively characterize the iontophoretic transport pathways (follicular (F) versus nonfollicular (NF) of the fluorescently-labeled poly-L-lysines employed. METHODS: A series of fluorescently-labeled poly-L-lysines (FITC-PLLs) [4 KDa, 7 KDa and 26 KDa] were used to study the extent and distribution of iontophoretic skin penetration as a function of MW using laser scanning confocal microscopy (LSCM). RESULTS: It was found that, relative to the passive controls, and under the electrical conditions considered, iontophoresis greatly enhanced the penetration of the 4 KDa analog, slightly elevated the delivery of the 7 KDa FITC-PLL, but had no effect on the transport of the larger 26 KDa FITC-PLL. Quantitative analyses of LSCM images revealed that iontophoresis increased transport via F pathways only slightly more than that through NF pathways for the 4 KDa and 7 KDa FITC-PLL molecules. CONCLUSIONS: It is visually apparent that the iontophoretic transport pathways taken are importantly determined by the physicochemical properties (including size and charge) of the penetrant. The results presented here demonstrate an inverse dependence of iontophoretic delivery upon the MW of the penetrant.

Studies of the potential role of the dopamine D1 receptor gene in addictive behaviors.

Abnormalities in the dopaminergic reward pathways have frequently been implicated in substance abuse and addictive behaviors. Recent studies by Self and coworkers have suggested an important interaction between the dopamine D1 and D2 receptors in cocaine abuse. To test the hypothesis that the DRD1 gene might play a role in addictive behaviors we examined the alleles of the Dde I polymorphism in three independent groups of subjects with varying types of compulsive, addictive behaviors-Tourette syndrome probands, smokers and pathological gamblers. In all three groups there was a significant in the frequency of homozygosity for the DRD1 Dde I 1 or 2 alleles in subjects with addictive behaviors. The DRD1 11 or 22 genotype was present in 41.3% of 63 controls and 57.3% of 227 TS probands (P = 0.024). When 23 quantitative traits were examined by ANOVA those carrying the 11 genotype consistently had the highest scores. Based on these results, we examined the prevalence of the 11 genotype in controls, TS probands without a specific behavior, and TS probands with a specific behavior. There was a progressive, linear increase, significant at alpha < or = 0.005 for scores for gambling, alcohol use and compulsive shopping. Problems with three additional behaviors, drug use, compulsive eating and smoking were significant at alpha < or = 0.05. All six variables were related to addictive behaviors. In a totally separate group of controls and individuals attending a smoking cessation clinic, and smoking at least one pack per day, 39.3% of the controls versus 66.1% of the smokers carried the 11 or 22 genotype (P = 0.0002). In a third independent group of pathological gamblers, 55.8% carried the 11 or 22 genotype (P = 0.009 vs the combined controls). In the TS group and smokers there was a significant additive effect of the DRD1 and DRD2 genes. The results for both the DRD1 and DRD2 genes, which have opposing effects on cyclic AMP, were consistent with negative and positive heterosis, respectively. These results support a role for genetic variants of the DRD1 gene in some addictive behaviors, and an interaction of genetic variants at the DRD1 and DRD2 genes.

The safety of transdermal nicotine as an aid to smoking cessation in patients with cardiac disease.

BACKGROUND: Transdermal nicotine therapy is widely used to aid smoking cessation, but there is uncertainty about its safety in patients with cardiac disease. METHODS: In a randomized, double-blind, placebo-controlled trial at 10 Veterans Affairs medical centers, we randomly assigned 584 outpatients (of whom 576 were men) with at least one diagnosis of cardiovascular disease to a 10-week course of transdermal nicotine or placebo as an aid to smoking cessation. The subjects were monitored for a total of 14 weeks for the primary end points of the study (death, myocardial infarction, cardiac arrest, and admission to the hospital due to increased severity of angina, arrhythmia, or congestive heart failure); the secondary end points (admission to the hospital for other reasons and outpatient visits necessitated by increased severity of heart disease); any side effects of therapy; and abstinence from smoking. RESULTS: There were 48 primary and 78 secondary end points noted in a total of 95 subjects. At least one of the primary end points was reached by 5.4 percent of the subjects in the nicotine group and 7.9 percent of the subjects in the placebo group (difference, 2.5 percent; 95 percent confidence interval, -1.6 to 6.5 percent; P=0.23). In the nicotine group, 11.9 percent of the subjects had at least one of the secondary end points, as compared with 9.7 percent in the placebo group (difference, 2.2 percent; 95 percent confidence interval, -2.2 to 7.4 percent; P= 0.37). After 14 weeks the rate of abstinence from smoking was 21 percent in the nicotine group, as compared with 9 percent in the placebo group (P=0.001), but after 24 weeks the abstinence rates were not significantly different (14 percent vs. 11 percent, P= 0.67). CONCLUSIONS: Transdermal nicotine does not cause a significant increase in cardiovascular events in high-risk outpatients with cardiac disease. However, the efficacy of transdermal nicotine as an aid to smoking cessation in such patients is limited and may not be sustained over time.

Exon and intron variants in the human tryptophan 2,3-dioxygenase gene: potential association with Tourette syndrome, substance abuse and other disorders.

Defects in serotonin metabolism, and abnormalities in both blood serotonin and tryptophan levels, have been reported in many psychiatric disorders. Tryptophan 2,3-dioxygenase (TDO2) is the rate limiting enzyme for the breakdown of tryptophan to N-formyl kenurenine. Functional variants of this gene could account for the observed simultaneous increases or decreases of both serotonin and tryptophan in various disorders. We have identified four different polymorphisms of the human TDO2 gene. Association studies show a significant association of one or more of these polymorphisms and Tourette syndrome (TS), attention deficit hyperactivity disorder (ADHD) and drug dependence. The intron 6G-->T variant was significantly associated with platelet serotonin levels. Only the association with TS was significant with a Bonferroni correction (p = 0.005). Our purpose here is not to claim these associations are proven, but rather to report preliminary results and show that easily testable polymorphisms are available. We hope to encourage additional research into the potential role the TDO2 gene in these and other psychiatric disorders.

The dopamine D2 receptor (DRD2) gene: a genetic risk factor in smoking.

Of a group of 312 non-Hispanic Caucasians who smoked at least one pack per day, had unsuccessfully attempted to stop smoking, and were free of alcohol or other drug dependence, 48.7% carried the A1 allele of the DRD2 gene. This was significantly greater than the 25.9% prevalence in the 714 known non-Hispanic Caucasian controls without alcohol or drug abuse, p < 10(-8), and significantly greater than in a smaller set of our study controls. There was a significant, inverse relationship between the prevalence of the D2A1 allele and the age of onset of smoking, p = 0.02, and the maximum duration of time the smokers had been able to quit smoking on their own, p = 0.02. These results suggest the DRD2 gene is one of a multifactorial set of risk factors associated with smoking.

Heterocercal tail function in leopard sharks: a three-dimensional kinematic analysis of two models

Two different models have been proposed to explain the function of the heterocercal tail in shark locomotion. The classical model proposes that, as a result of lift generated by the tail as it beats, the net force acting on the tail is directed dorsally and anteriorly. In contrast, Thomson's model suggests that the tail generates a net force directed through the shark's center of gravity, i.e. ventrally and anteriorly. In this study, we evaluate these two models by describing the three-dimensional kinematics of the heterocercal tail in the leopard shark Triakis semifasciata during swimming. Lateral and posterior views of the tail were examined from four individuals swimming in a flow tank at 1.2 L s-1 (where L is total length) using two high-speed video cameras filming simultaneously at 250 fields s-1. These two simultaneous views allowed eight landmarks on the tail to be followed in three dimensions through time. These landmarks allowed the tail to be divided into separate surfaces whose orientation over time was calculated. Points located anteriorly on the tail go through significantly smaller excursions and reach their maximum lateral excursion significantly earlier in the beat cycle than points on the trailing edge of the tail. Three-dimensional angle calculations show that the terminal lobe leads the ventral lobe through a beat, as predicted by the classical model. Dye-stream visualizations confirmed that this pattern of movement deflects water ventrally and posteriorly to the moving tail, providing strong support for the classical model. Additionally, our results show that a three-dimensional analysis is critical to understanding the function of the heterocercal tail.

Theoretical model of iontophoresis utilized in transdermal drug delivery.

A theoretical model of in vitro iontophoresis that utilizes radial mass transport is presented. The applicability of radial transport to the skin morphology of different species is determined by the density of low-resistance pores, which represents the density of skin appendages such as hair follicles or sweat glands. Radial transport is expected to dominate in the case where appendage density is low, in contrast to the linear transport mechanism that would dominate in the case of skin with high appendage density. Parameters such as the effective surface area of highly conductive pores and boundary-layer thickness are defined for the radial and linear transport limits and evaluated for the iontophoretic flux of pindolol hydrochloride through porcine skin. Based upon a decrease in the calculated boundary-layer thickness and an increase in drug flux with current density to a limiting value, it is concluded that radial mass transport is the dominant mechanism of iontophoretic transport under the experimental conditions described.

Smoking characteristics of female veterans.

Recent studies suggest that the prevalence of smoking among active duty military women is higher than that of active duty military men or civilians of either gender. No data have been published on cessation rates among female veterans. We wanted to report such rates in a group of female veterans at Pettis VAMC Preventive Medicine Clinic and to study predictive factors for smoking cessation and prevention. We identified female patients at Pettis VAMC Preventive Medicine Women's Clinic who had received services in the past 3 years or who enrolled as new patients during the study period; 529 received questionnaires by mail or at the clinic; 409 returned completed surveys. A high proportion (32.5%) of our sample of female veterans were current smokers, and 67% of female veteran smokers reported smoking at least one pack daily. More than one-third of ever-smokers began smoking during military service. Thirty-nine percent of the female veteran sample had CES-D scores of 16 or greater, and current smokers had significantly greater mean CES-D scores than former smokers. Twenty-three percent of current smokers had high nicotine dependence scores (> 7). The highest proportion of CES-D scores compatible with depressive symptoms (55%) was seen among current smokers who consumed a pack or more of cigarettes per day. Ever-smokers who screened as depressed were significantly less likely to have quit than those with lower CES-D scores; however, in multivariate models, CES-D scores were not significantly related to cessation. The prevalence of current, ever, and heavy smoking was high among this sample of female veterans attending a VAMC Preventive Medicine clinic. An unexpectedly high prevalence of screening scores compatible with depression was found among this sample, particularly among smokers. This warrants further investigation, particularly in light of the reported relationship between depression and smoking.