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Sample records for 2-year study conducted

  1. Learning, Memory, and Executive Function in New MDMA Users: A 2-Year Follow-Up Study

    PubMed Central

    Wagner, Daniel; Tkotz, Simon; Koester, Philip; Becker, Benjamin; Gouzoulis-Mayfrank, Euphrosyne; Daumann, Joerg

    2015-01-01

    3,4-Methylenedioxymethamphetamine (MDMA) is associated with changes in neurocognitive performance. Recent studies in laboratory animals have provided additional support for the neurodegeneration hypothesis. However, results from animal research need to be applied to humans with caution. Moreover, several of the studies that examine MDMA users suffer from methodological shortcomings. Therefore, a prospective cohort study was designed in order to overcome these previous methodological shortcomings and to assess the relationship between the continuing use of MDMA and cognitive performance in incipient MDMA users. It was hypothesized that, depending on the amount of MDMA taken, the continued use of MDMA over a 2-year period would lead to further decreases in cognitive performance, especially in visual paired association learning tasks. Ninety-six subjects were assessed, at the second follow-up assessment: 31 of these were non-users, 55 moderate-users, and 10 heavy-users. Separate repeated measures analyses of variance were conducted for each cognitive domain, including attention and information processing speed, episodic memory, and executive functioning. Furthermore, possible confounders including age, general intelligence, cannabis use, alcohol use, use of other concomitant substances, recent medical treatment, participation in sports, level of nutrition, sleep patterns, and subjective well-being were assessed. The Repeated measures analysis of variance (rANOVA) revealed that a marginally significant change in immediate and delayed recall test performances of visual paired associates learning had taken place within the follow-up period of 2 years. No further deterioration in continuing MDMA-users was observed in the second follow-up period. No significant differences with the other neuropsychological tests were noted. It seems that MDMA use can impair visual paired associates learning in new users. However, the groups differed in their use of concomitant use of

  2. A 2-year longitudinal study of prospective predictors of pathological Internet use in adolescents.

    PubMed

    Strittmatter, Esther; Parzer, Peter; Brunner, Romuald; Fischer, Gloria; Durkee, Tony; Carli, Vladimir; Hoven, Christina W; Wasserman, Camilla; Sarchiapone, Marco; Wasserman, Danuta; Resch, Franz; Kaess, Michael

    2016-07-01

    Longitudinal studies of prospective predictors for pathological Internet use (PIU) in adolescents as well as its course are lacking. This three-wave longitudinal study was conducted within the framework of the European Union-funded project "Saving and Empowering Young Lives in Europe" over a 2-year period. The sample consisted of 1444 students at the baseline investigation (T0); 1202 students after 1 year (T1); and 515 students after 2 years (T2). Structured self-report questionnaires were administered at all three time points. PIU was assessed using the Young Diagnostic Questionnaire (YDQ). In addition, demographic (i.e., gender), social (i.e., parental involvement), psychological (i.e., emotional problems), and Internet use-related factors (i.e., online activities) were assessed as prospective predictors. The prevalence of PIU was 4.3 % at T0, 2.7 % at T1 and 3.1 % at T2. However, only 3 students (0.58 %) had persistent categorical PIU (YDQ score of ≥5) over the 2-year period. In univariate models, a variety of variables that have been previously identified in cross-sectional investigations predicted PIU at T2. However, multivariate regression demonstrated that only previous PIU symptoms and emotional problems were significant predictors of PIU 2 years later (adjusted R (2) 0.23). The stability of categorical PIU in adolescents over 2 years was lower than previously reported. However, current PIU symptoms were the best predictor of later PIU; emotional symptoms also predicted PIU over and above the influence of previous problematic Internet use. Both PIU symptoms and emotional problems may contribute to the vicious cycle that supports the perpetuation of PIU.

  3. Improving Social Competence through Emotion Knowledge in 2-Year-Old Children: A Pilot Study

    ERIC Educational Resources Information Center

    Giménez-Dasí, Marta; Fernández-Sánchez, Marta; Quintanilla, Laura

    2015-01-01

    Research Findings: The goal of this study was to determine the efficacy of an educational intervention program to improve emotion knowledge, emotion regulation, and social competence in 2-year-old Spanish children. This study makes two original contributions because there are no validated education programs for such young children and because it…

  4. Saliva in perimenopausal and early postmenopausal women. A 2-year follow-up study.

    PubMed

    Tarkkila, Laura; Furuholm, Jussi; Tiitinen, Aila; Meurman, Jukka H

    2012-06-01

    This study aims to investigate salivary flow and biochemical constituents of menopausal-age women with the hypothesis that women using hormone therapy (HT) might present better saliva values than non-users. Two hundred HT users and 200 non-users were selected at random from a cohort study of 3,173 peri- and postmenopausal women and invited to a 2-year clinical follow-up study. Clinical examination with saliva sampling was made at baseline and 2 years later. Salivary total protein, albumin, and immunoglobulin (Ig) concentrations were analyzed. Final material included 106 consistent HT users and 55 non-users. Backward logistic regression analysis was made to determine the risk factors for higher or lower than medium salivary protein values. No difference was seen in salivary flow rate, total protein, and IgA values between baseline and follow-up measurements or between the groups. Albumin, IgG, and IgM concentrations were significantly lower in the 2-year samples of the HT group when compared with baseline. IgA and IgM values were higher in the non-HT 2-year samples when compared with the corresponding HT samples. The only significant explanatory factor for higher than median salivary albumin concentration was the number of teeth both at baseline and 2 years later. HT possibly improved epithelial integrity since the concentrations of serum components albumin, IgG, and IgM decreased during the follow-up. HT as such does not seem to affect saliva, although it may modify it. The clinical relevance of these results needs to be assessed in future studies.

  5. Uric acid in relapsing-remitting multiple sclerosis: a 2-year longitudinal study.

    PubMed

    Moccia, Marcello; Lanzillo, Roberta; Costabile, Teresa; Russo, Cinzia; Carotenuto, Antonio; Sasso, Gabriella; Postiglione, Emanuela; De Luca Picione, Carla; Vastola, Michele; Maniscalco, Giorgia Teresa; Palladino, Raffaele; Brescia Morra, Vincenzo

    2015-01-01

    Uric acid (UA) is reduced in multiple sclerosis (MS), and possibly relates to MS outcomes, with lower UA levels in subjects experiencing a relapse or presenting higher disability scores. The present retrospective longitudinal study evaluated UA variations in MS, in relation to clinical relapses, disability progression, and cognitive functions. We included 141 subjects with relapsing-remitting MS (RRMS) and performed expanded disability status scale (EDSS), symbol digit modalities test (SDMT) and UA evaluation at baseline visit and after 2-year follow-up. Paired t test showed significantly lower UA levels after 2-year follow-up than at baseline (3.987 ± 1.135 and 4.167 ± 1.207 mg/dL, respectively) (p = 0.001). The difference in UA levels between 2-year follow-up and baseline related to EDSS sustained progression (p < 0.001; OR = 0.099), and presented a trend for clinical relapses at logistic regression (p = 0.211; OR = 0.711) and for the time to relapse at Cox regression (p = 0.236; HR = 0.792). Analysis of variance showed reduced baseline UA levels in subjects with impaired SDMT at baseline (p = 0.045; adjusted R(2) = 0.473) and after 2-year follow-up (p = 0.034; adjusted R(2) = 0.470). This is the first study showing a progressive reduction of UA levels during the course of RRMS, suggesting a progressive decrease of antioxidant reserves, in relation to relapse risk, disability progression and cognitive function.

  6. Financial impact of allogeneic hematopoietic cell transplantation on patients and families over 2 years: results from a multicenter pilot study.

    PubMed

    Denzen, E M; Thao, V; Hahn, T; Lee, S J; McCarthy, P L; Rizzo, J D; Ammi, M; Drexler, R; Flesch, S; James, H; Omondi, N; Murphy, E; Pederson, K; Majhail, N S

    2016-09-01

    Hematopoietic cell transplantation (HCT) is a procedure that can significantly influence the socioeconomic wellbeing of patients, caregivers and their families. Among 30 allogeneic HCT recipients and their caregivers enrolled on a pilot study evaluating the feasibility of studying financial impact of HCT, 16 agreed to participate in the long-term phase, completed a baseline questionnaire and received phone interviews at 6, 12, 18 and 24 months post HCT. Analyses showed that by 2 years post HCT, 54% of patients who previously contributed to household earnings had not returned to work and 80% of patients/caregivers reported transplant as having moderate to great impact on household income. However, patients' levels of confidence in their abilities to meet household financial obligations increased from baseline to 2 years. A relatively large proportion of patients reported inability to pay for medical care through this time period. Case studies demonstrated that patients' individual perceptions of the financial impact of HCT varies considerably, regardless of actual income. We demonstrate the feasibility of conducting a study to evaluate the financial impact of allogeneic HCT through 2 years post transplantation. Some patients/caregivers continue to experience a significant long-term financial burden after this procedure. Our study lays the foundation for a larger evaluation of patient/caregiver financial burden associated with HCT.

  7. Financial Impact of Allogeneic Hematopoietic Cell Transplantation on Patients and Families over 2-years: Results from a Multicenter Pilot Study

    PubMed Central

    Denzen, Ellen M.; Thao, Viengneesee; Hahn, Theresa; Lee, Stephanie J.; McCarthy, Philip L.; Rizzo, J. Douglas; Ammi, Monique; Drexler, Rebecca; Flesch, Susan; James, Heather; Omondi, Nancy; Murphy, Elizabeth; Pederson, Kate; Majhail, Navneet S.

    2016-01-01

    Hematopoietic cell transplantation (HCT) is a procedure that can significantly influence the socioeconomic wellbeing of patients, caregivers and their families. Among 30 allogeneic HCT recipients and their caregivers enrolled on a pilot study evaluating the feasibility of studying financial impact of HCT, 16 agreed to participate in the long-term phase, completed a baseline questionnaire and received phone interviews at 6, 12, 18 and 24 months post-HCT. Analyses showed that by 2-years post-HCT, 54% of patients who previously contributed to household earnings had not returned to work and 80% of patients/caregivers reported transplant as having moderate to great impact on household income. However, patients’ level of confidence in their ability to meet household financial obligations increased from baseline to 2-years. A relatively large proportion of patients reported inability to pay for medical care through this time period. Case studies demonstrated patient individual perception of financial impact of HCT varies considerably, regardless of actual income. We demonstrate the feasibility of conducting a study to evaluate financial impact of allogeneic HCT through 2-years post-transplantation. Some patients/caregivers continue to experience significant long-term financial burden after this procedure. Our study lays the foundation for a larger evaluation of patient/caregiver financial burden associated with HCT. PMID:27088381

  8. Clinical outcomes and mortality after hip fracture: a 2-year follow-up study.

    PubMed

    Baudoin, C; Fardellone, P; Bean, K; Ostertag-Ezembe, A; Hervy, F

    1996-03-01

    The aim of this study was to evaluate the burden of hip fractures, which occurred in the French region of Picardie, in 1992, among 1103 women and 356 men, whether the fractures occurred at home or in a community (i.e., patients who depended on a collective service). The data are part of the PICAROS study, which was designed to assess prospectively the outcome of patients as judged by clinical, economical, and quality of life factors. Patients and/or proxies were questioned during the 2nd or 3rd week following the fracture, and again at 3, 6, 12, and 24 months after the fracture. The survey was conducted by home interview. Recruitment criteria were: 1) all patients with a hip fracture as defined by the International Classification of Disease (ICD); 2) 20 years of age and over; 3) admitted to one of the 34 surgical units from the region, public and private, and had an operation or not. Patients with metastatic or myelomatous fractures or fractures on prothesis device were not included. For the present analysis, patients under 50 years of age were excluded. Among people aged 50 years and over, 3% of the general population lived in a community; 32% of hip fractures were from a community. Patients in a community, aged 60-69, had 15 times more risk of having a hip fracture than subjects of the same age at home. The excess risk decreased with age and stabilized over 85 years of age at two to threefold. During the 24 month follow-up, 394 women and 173 men died. Among those surviving, 87% were interviewed at 2 years. We analysed seven classes of complications, according to the ICD: (1) pressure sores and blisters; (2) pulmonary infections; (3) urinary infections; (4) surgical complications; (5) orthopedic complications; (6) thrombosis and embolisms; and (7) secondary hip fractures. Patients coming from a community had a higher risk of mortality, pressure sores, surgical complications, and pulmonary and urinary infections. From an economical perspective, the

  9. Efficacy and safety of eculizumab in atypical hemolytic uremic syndrome from 2-year extensions of phase 2 studies.

    PubMed

    Licht, Christoph; Greenbaum, Larry A; Muus, Petra; Babu, Sunil; Bedrosian, Camille L; Cohen, David J; Delmas, Yahsou; Douglas, Kenneth; Furman, Richard R; Gaber, Osama A; Goodship, Timothy; Herthelius, Maria; Hourmant, Maryvonne; Legendre, Christophe M; Remuzzi, Giuseppe; Sheerin, Neil; Trivelli, Antonella; Loirat, Chantal

    2015-05-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare, possibly life-threatening disease characterized by platelet activation, hemolysis and thrombotic microangiopathy (TMA) leading to renal and other end-organ damage. We originally conducted two phase 2 studies (26 weeks and 1 year) evaluating eculizumab, a terminal complement inhibitor, in patients with progressing TMA (trial 1) and those with long duration of aHUS and chronic kidney disease (trial 2). The current analysis assessed outcomes after 2 years (median eculizumab exposure 100 and 114 weeks, respectively). At all scheduled time points, eculizumab inhibited terminal complement activity. In trial 1 with 17 patients, the platelet count was significantly improved from baseline, and hematologic normalization was achieved in 13 patients at week 26, and in 15 patients at both 1 and 2 years. The estimated glomerular filtration rate (eGFR) was significantly improved compared with baseline and year 1. In trial 2 with 20 patients, TMA event-free status was achieved by 16 patients at week 26, 17 patients at year 1, and 19 patients at year 2. Criteria for hematologic normalization were met by 18 patients at each time point. Improvement of 15 ml/min per 1.73 m(2) or more in eGFR was achieved by 1 patient at week 26, 3 patients at 1 year, and 8 patients at 2 years. The mean change in eGFR was not significant compared with baseline, week 26, or year 1. Eculizumab was well tolerated, with no new safety concerns or meningococcal infections. Thus, a 2-year analysis found that the earlier clinical benefits achieved by eculizumab treatment of aHUS were maintained at 2 years of follow-up.

  10. Equipping public health professionals for youth engagement: lessons learned from a 2-year pilot study.

    PubMed

    Sahay, Tina Binita; Rempel, Benjamin; Lodge, Jennifer

    2014-01-01

    There is strong evidence of the positive role that youth engagement programs and policies play in creating resiliency and producing positive outcomes among youth populations, such as delaying or avoiding the onset of risk-taking behaviors. Research also suggests that achieving positive outcomes ideally includes influence from the individual, the family, the school, the community, and the field of public health (available in A Research Report and Recommendations for Ontario Public Health Association). The authors conducted a comprehensive evaluation of a 2-year pilot project designed to increase the application of engagement and resiliency theory, knowledge, and skills among public health professionals engaging students from Grades 6, 7, and 8 (11- to 14-year-olds). Qualitative methods assessed public health satisfaction with training, resources, and networking activities, whereas quantitative methods assessed changes in capacity with respect to youth engagement knowledge, awareness, confidence, and skills. The findings have helped shed light on public health professional needs concerning capacity and confidence to undertake youth engagement work. Key lessons learned about making youth engagement possible and effective for public health professionals are presented.

  11. Can patients with eating disorders learn to eat intuitively? A 2-year pilot study.

    PubMed

    Richards, P Scott; Crowton, Sabree; Berrett, Michael E; Smith, Melissa H; Passmore, Kimberly

    2017-01-01

    The present article reports on a 2-year pilot study that evaluated the effectiveness of an intuitive eating program for patients in an eating disorder treatment center. Standardized measures of intuitive eating and eating disorder and psychological symptoms were administered. Psychotherapists and dietitians rated patients on the healthiness of their eating attitudes and behaviors. Preliminary findings indicated that patients can develop the skills of intuitive eating, and that the ability to eat intuitively is associated with positive treatment outcomes for each diagnostic category (i.e., anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified). We conclude by offering recommendations about how to implement intuitive eating training safely and effectively in inpatient and residential treatment programs.

  12. Consultation training of nurses for cardiovascular prevention - a randomized study of 2 years duration.

    PubMed

    Drevenhorn, Eva; Bengtson, Ann; Nilsson, Peter M; Nyberg, Per; Kjellgren, Karin I

    2012-10-01

    The aim of this study was to increase patients' adherence to the treatment of hypertension through the consultation training of nurses. Thirty-three nurses were included in the study. In the intervention group (IG), 19 nurses took part in a 3-day residential training course on the Stages of Change model, Motivational Interviewing and guidelines for cardiovascular prevention, and recruited 153 patients. Sixteen nurses in the control group (CG) recruited 59 patients. A decrease in systolic and diastolic blood pressure and total cholesterol was noticed in both groups over the 2 years. Heart rate (p = 0.027), body mass index (p = 0.019), weight (p = 0.0001), waist (p = 0.041), low-density lipoprotein-cholesterol (p = 0.0001), the waist-hip ratio (p = 0.024), and perceived stress (p = 0.001) decreased to any great extent only in the IG. After 2 years, 52.6% of the patients in the IG (p = 0.13) reached the target of ≤ 140/90 mmHg in blood pressure compared with 39.2% in the CG. For self-reported physical activity, there was a significant (p = 0.021) difference between the groups. The beneficial effects of the consultation training on patients' weight parameters, physical activity, perceived stress and the proportion of patients who achieved blood pressure control emphasize consultation training and the use of behavioural models in motivating patients to adhere to treatment.

  13. Collagenase injections for Dupuytren's disease: prospective cohort study assessing 2-year treatment effect durability

    PubMed Central

    Lauritzson, Anna; Atroshi, Isam

    2017-01-01

    Objectives To assess 2-year durability of joint contracture correction following collagenase injections for Dupuytren's disease. Design Prospective cohort study. Setting Orthopaedic Department in Sweden. Participants Patients with palpable Dupuytren's cord and active extension deficit (AED) ≥30° in the metacarpophalangeal (MCP) and/or proximal interphalangeal (PIP) joint. A surgeon injected 0.80 mg collagenase into multiple cord parts and performed finger manipulation under local anaesthesia after 24–48 hours. A hand therapist measured joint contracture before and 5 weeks after injection in all treated patients. Of 57 consecutive patients (59 hands), 48 patients (50 hands) were examined by a hand therapist 24–35 months (mean 26) after injection. Five of the patients had received a second injection in the same finger within 6 months of the first injection. Outcome measures Primary outcome was proportion of treated joints with ≥20° worsening in AED from 5 weeks to 2 years. Results Between the 5-week and the 2-year measurements, AED had worsened by ≥20° in seven MCP and seven PIP joints (28% of the treated hands; all had received a single injection). Mean AED for the MCP joints was 54° before injection, 6° at 5 weeks and 9° at 2 years and for the PIP joints 30°, 13° and 16°, respectively. For joints with ≥10° contracture at baseline, mean (95 % CI) baseline to 2 years AED improvement was for MCP 49° (41–54) and for PIP 25° (17–32). No treatment-related adverse events were observed at the 2-year follow-up evaluation. Conclusions Two years after collagenase injections for Dupuytren's disease, improvement was maintained in 72% of the treated hands. Complete contracture correction was seen in more than 80% of the MCP but in less than half of the PIP joints. PMID:28298365

  14. Sustained efficacy of risedronate in men with primary and secondary osteoporosis: results of a 2-year study.

    PubMed

    Ringe, Johann D; Farahmand, Parvis; Faber, Herbert; Dorst, Alfred

    2009-01-01

    The aim of this study was to assess the effect of treatment with risedronate 5 mg daily relative to control in men with primary or secondary osteoporosis over 2 years. Osteoporosis is a common condition in men that can have serious clinical consequences. In an earlier interim report, we found that 1 year of risedronate therapy resulted in significant increases in bone mineral density (BMD) and a significant reduction in vertebral fractures compared to control in men with osteoporosis. We conducted an open-label, prospective, match-control trial on men with primary or secondary osteoporosis in a single center, outpatient setting. Men with primary or secondary osteoporosis, as defined by a baseline lumbar spine BMD T-score < or = -2.5 and a baseline femoral neck BMD T-score < or = 2.0, were eligible for this study. Patients who had been treated with bisphosphonates or fluoride within the last 12 months were excluded. A total of 316 men were randomized to risedronate (n = 158) or control (n = 158). Patients were stratified by the presence of prevalent vertebral fractures at baseline and case by case allocated to either daily treatment with risedronate 5 mg daily plus calcium (1,000 mg) and vitamin D (800 IU) or to a control group (daily alfacalcidol (1 microg) plus calcium (500 mg) for those with prevalent vertebral fractures; daily vitamin D (800 IU) plus calcium (1,200 mg) for those without previous vertebral fractures). Primary study end points were identified prior to study initiation as the incidence of new vertebral fractures and changes in BMD at the lumbar spine, femoral neck, and total hip. Other end points included incidence of nonvertebral fractures and change in body height and back pain. Compared to control, the incidence of new vertebral fractures was significantly reduced in the risedronate 5 mg daily group at 2 years [14/152 (9.2%) for risedronate vs. 35/148 (23.6%) for control (61% risk reduction; P = 0.0026)]. Treatment with risedronate 5 mg daily

  15. A 2-Year Psychological Autopsy Study of Completed Suicides in the Athens Greater Area, Greece

    PubMed Central

    Michopoulos, Ioannis; Christodoulou, Christos; Koutsaftis, Filippos; Lykouras, Lefteris; Douzenis, Athanassios

    2015-01-01

    Objective To study the characteristics of a sample of suicide victims from the Athens Greater Area using the psychological autopsy method for the first time in Greece. Methods We studied all recorded cases of completed suicide for the 2-year time period November 2007-October 2009 collecting data from the victims' forensic records as well as from the completion of a psychological autopsy questionnaire. Results 335 persons were recorded as suicide victims. We contacted relatives of 256 victims interviewing those of 248 of them (96.9%). The differences regarding sex, marital and employment status between our sample and the general population were statistically significant (p<0.001). The male/female ratio was 3:1. Comparatively more victims were divorced, separated or single and a greater proportion were pensioners or unemployed. 26.0% of the victims had history of prior attempts (64.4% once, 20.3% twice and 15.3% more times). 42.6% were taking psychiatric medication-significantly more women than men according to blood tests; 14.2% had been hospitalized in a psychiatric clinic the year prior to their death. 84.8% have deceased at the place of suicide and 15.2% died in the hospital; 80.3% died indoors and 19.7% outdoors. Men died primarily by hanging or shooting by a firearm while women preferred jumping from height instead (p<0.001). As many as 48.8% had expressed their intention to die to their relatives; 26.6% left a suicide note. Conclusion Our study has shown that the psychological autopsy method is applicable and widely accepted yielding results comparable to the international literature. Specific parameters associated with suicide have been studied for the first time in Greece. PMID:25866522

  16. Effect of exacerbations on quality of life in patients with chronic obstructive pulmonary disease: a 2 year follow up study

    PubMed Central

    Miravitlles, M; Ferrer, M; Pont, A; Zalacain, R; Alvarez-Sala, J; Masa, F; Verea, H; Murio, C; Ros, F; Vidal, R

    2004-01-01

    Background: A study was undertaken to evaluate exacerbations and their impact on the health related quality of life (HRQL) of patients with chronic obstructive pulmonary disease (COPD). Methods: A 2 year follow up study was performed in 336 patients with COPD of mean (SD) age 66 (8.2) years and mean (SD) forced expiratory volume in 1 second (FEV1) 33 (8)% predicted. Spirometric tests, questions regarding exacerbations of COPD, and HRQL measurements (St George's Respiratory Questionnaire (SGRQ) and SF-12 Health Survey) were conducted at 6 month intervals. Results: A total of 1015 exacerbations were recorded, and 103 (30.7%) patients required at least one hospital admission during the study. After adjustment for baseline characteristics and season of assessment, frequent exacerbations had a negative effect on HRQL in patients with moderate COPD (FEV1 35–50% predicted); the change in SGRQ total score of moderate patients with ⩾3 exacerbations was almost two points per year greater (worse) than those with <3 exacerbations during the follow up (p = 0.042). For patients with severe COPD (FEV1 <35% predicted) exacerbations had no effect on HRQL. The change in SGRQ total score of patients admitted to hospital was almost 2 points per year greater (worse) than patients not admitted, but this effect failed to show statistical significance in any severity group. There was a significant and independent seasonal effect on HRQL since SGRQ total scores were, on average, 3 points better in measurements performed in spring/summer than in those measured in the winter (p<0.001). Conclusions: Frequent exacerbations significantly impair HRQL of patients with moderate COPD. A significant and independent effect of seasonality was also observed. PMID:15115864

  17. Reduced prepulse inhibition in adolescents at risk for psychosis: a 2-year follow-up study

    PubMed Central

    Ziermans, Tim; Schothorst, Patricia; Magnée, Maurice; van Engeland, Herman; Kemner, Chantal

    2011-01-01

    Background Reduced prepulse inhibition (PPI) of the auditory startle reflex is a hallmark feature of attention-processing deficits in patients with schizophrenia and other psychotic disorders. Recent evidence suggests that these deficits may also be present before the onset of psychosis in individuals at ultra-high risk (UHR) and become progressively worse as psychosis develops. We conducted a longitudinal follow-up study to observe the development of PPI over time in UHR adolescents and healthy controls. Methods Two-year follow-up data of PPI measures were compared between UHR adolescents and a matched control group of typically developing individuals. Results We included 42 UHR adolescents and 32 matched controls in our study. Compared with controls, UHR individuals showed reduced PPI at both assessments. Clinical improvement in UHR individuals was associated with an increase in PPI parameters. Limitations A developmental increase in startle magnitude partially confined the interpretation of the association between clinical status and PPI. Furthermore, post hoc analyses for UHR individuals who became psychotic between assessments had limited power owing to a low transition rate (14%). Conclusion Deficits in PPI are present before the onset of psychosis and represent a stable vulnerability marker over time in UHR individuals. The magnitude of this marker may partially depend on the severity of clinical symptoms. PMID:21266126

  18. Anaphylaxis in an emergency department: a 2-year study in a tertiary-care hospital.

    PubMed

    Piromrat, Kanika; Chinratanapisit, Sasawan; Trathong, Sommai

    2008-01-01

    The aim of this study was to estimate the incidence of anaphylaxis in the emergency department of a tertiary-care hospital, describe the clinical features and the management of the patients and determine those with mild manifestations. A retrospective study was conducted from 2005 to 2006 using anaphylaxis-related ICD-10 terms. Two different sets of criteria for the diagnosis of anaphylaxis were applied, first the criteria previously accepted by emergency practice, followed by the recent criteria set forth at the 2005 international meeting. Sixty-four patients fulfilled the previous criteria with an average incidence of 52.5 per 100,000 patients per year with a shift towards females in 2006. The most common presentations were cutaneous, followed by respiratory symptoms. Food allergy was the most common cause, especially prawn. After applying the recent criteria, 13 patients (20.4%) were excluded, which reduced the incidence to 42.2 per 100,000 patients per year. Long term follow up is suggested for the possible or mild cases that were re-categorized.

  19. Injury risk factors in junior tennis players: a prospective 2-year study.

    PubMed

    Hjelm, N; Werner, S; Renstrom, P

    2012-02-01

    The aim was to investigate injury risk factors in junior tennis players. Fifty-five players, 35 boys and 20 girls, answered a questionnaire about training habits, time of exposure, previous injuries and equipment factors. A battery of clinical tests and functional performance tests were also carried out. All tennis-related injuries that occurred during a 2-year period were identified and recorded. An injury was defined as an injury if it was impossible to participate in regular tennis training or playing matches during at least one occasion, a time loss injury. Potential injury risk factors were tested in a forward stepwise logistic regression model for injury. Thirty-nine players sustained totally 100 new and recurrent injuries. Injuries to the lower extremity were the most common ones (51%) followed by the upper extremity (24%) and the trunk (24%). Injured players performed more singles per week (P<0.0001) and played more tennis hours per year (P=0.016) than the uninjured players. Playing tennis more than 6 h/week was found to be a risk factor for back pain. A previous injury regardless of location was identified as an injury risk factor, and a previous injury to the back was a risk factor for back pain.

  20. Temporal Stability of Obsessive-Compulsive Symptom Dimensions in an Undergraduate Sample: A Prospective 2-Year Follow-Up Study

    ERIC Educational Resources Information Center

    Fullana, Miquel A.; Tortella-Feliu, Miquel; Caseras, Xavier; Taberner, Joan; Torrubia, Rafael; Mataix-Cols, David

    2007-01-01

    The temporal stability of obsessive-compulsive symptom dimensions was studied in a nonclinical student sample. The Obsessive-Compulsive Inventory--Revised was administered twice to 132 undergraduate students during a 2-year period. There were no significant changes in symptom dimension scores between the baseline and follow-up, except for the…

  1. Evolution of Charcot-Marie-Tooth disease type 1A duplication: a 2-year clinico-electrophysiological and lower-limb muscle MRI longitudinal study.

    PubMed

    Pelayo-Negro, Ana L; Gallardo, Elena; García, Antonio; Sánchez-Juan, Pascual; Infante, Jon; Berciano, José

    2014-04-01

    The objective of this study was to analyze Charcot-Marie-Tooth disease type 1A (CMT1A) evolution. We conducted a 2-year longitudinal study in 14 CMT1A patients and 14 age- and sex-matched controls. In the patients, we performed neurological examination with hand-held dynamometry, electrophysiology, and lower-limb muscle MRI, both at baseline and 2 years later, while controls were examined at baseline only. Patients' ages ranged from 12 to 51 years. Outstanding manifestations on initial evaluation included pes cavus, areflexia, lower-limb weakness, and foot hypopallesthesia. In evaluating muscle power, good correlation was observed between manual testing and dynamometry. Compared to controls, Lunge, 10-Meter-Walking, and 9-Hole-Peg tests were impaired. Their CMT neuropathy score and functional disability scale showed that patients exhibited mild phenotype and at most slight walking difficulty. Electrophysiology revealed marked nerve conduction slowing and variable compound muscle action potential amplitude reduction. On lower-limb muscle MRI, there was distally accentuated fatty infiltration accompanied by edema in calf muscles. All these clinico-electrophysiological and imaging findings remained almost unaltered during monitoring. Using multivariate analysis, no significant predictors of progression associated to the disease were obtained. We conclude that in the 2-year period of study, CMT1A patients showed mild progression with good concordance between clinico-electrophysiological and imaging findings.

  2. Evidence for safety and efficacy of risedronate in men with osteoporosis over 4 years of treatment: Results from the 2-year, open-label, extension study of a 2-year, randomized, double-blind, placebo-controlled study.

    PubMed

    Boonen, Steven; Lorenc, Roman S; Wenderoth, Dietrich; Stoner, Karen J; Eusebio, Rachelle; Orwoll, Eric S

    2012-09-01

    A 2-year, randomized, double-blind, placebo-controlled study in men with osteoporosis demonstrated that treatment with risedronate 35mg once a week significantly decreased bone turnover markers (BTMs) and increased bone mineral density (BMD). This study was extended to include a 2-year, open-label extension to continue to assess the safety and efficacy of risedronate in men with osteoporosis. In the open-label extension, all patients received risedronate 35mg once a week, and 1000mg elemental calcium and 400 to 500IU vitamin D daily for up to 2 years. The safety of risedronate was evaluated based on adverse events, laboratory data, vital signs, and physical examination results. BMD, BTMs, and the incidence of new vertebral fractures were also assessed. A total of 218 (of 284) patients enrolled in the open-label extension. Risedronate continued to produce significant increases in lumbar spine BMD from baseline (7.87%) in the group of patients who took it for 4 years. Risedronate produced significant increases in lumbar spine BMD from baseline (6.27%) in the former placebo group who took it for 2 years during the open-label extension. Few new vertebral and clinical fractures occurred during the study. There were no significant differences in BTMs between the two groups at months 36 and 48. Incidences of any upper GI adverse events during the extension were low and similar in the two groups; however, the percent of moderate to severe events were higher (8% versus 2%) in the group that received placebo prior to the extension. Safety results continued to show that risedronate was well-tolerated in men with osteoporosis. Patients who received risedronate 35mg once a week for 2years in the open-label extension study showed similar safety and efficacy results compared with those who received risedronate treatment in the first 2 double-blind years of the study. Patients who received risedronate for 4 years in total showed similar safety and efficacy to that observed in

  3. Treatment Compliance of Adolescents after Attempted Suicide: A 2-Year Follow-Up Study

    ERIC Educational Resources Information Center

    Burns, Craig D.; Cortell, Ranon; Wagner, Barry M.

    2008-01-01

    The study investigates compliance with mental health treatments among suicidal adolescents. Results show that child psychopathology and parental attitudes toward treatment plays an important part in increasing compliance with mental health treatment for adolescent suicide attempters.

  4. The Development of Falling Intonation in Young Children with Cochlear Implants: A 2-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Snow, David P.; Ertmer, David J.

    2013-01-01

    This article describes the development of intonation in 12 cochlear implant (CI) recipients. In a previously reported study of the first year of CI use, children who were implanted late (after 24 months) acquired intonation more rapidly than the younger participants. The older children's advantage is plausibly owing to their greater maturity.…

  5. Pubertal Timing and Substance Use in Middle Adolescence: A 2-Year Follow-Up Study

    ERIC Educational Resources Information Center

    Kaltiala-Heino, Riittakerttu; Koivisto, Anna-Maija; Marttunen, Mauri; Frojd, Sari

    2011-01-01

    Earlier research has associated early puberty with emotional and behavioral symptoms particularly among girls, while among boys, findings have been contradictory as to whether risks are associated with early or late pubertal timing. We studied the association between pubertal timing and substance use behaviors in middle adolescence in a 2-year…

  6. Diagnosis of Autism Spectrum Disorders in 2-Year-Olds: A Study of Community Practice

    ERIC Educational Resources Information Center

    Corsello, Christina M.; Akshoomoff, Natacha; Stahmer, Aubyn C.

    2013-01-01

    Background: Longitudinal research studies have demonstrated that experienced clinicians using standardized assessment measures can make a reliable diagnosis of autism spectrum disorders (ASDs) in children under age 3. Limited data are available regarding the sensitivity and specificity of these measures in community settings. The aims of this…

  7. Development of Orthographic Knowledge in German-Speaking Children: A 2-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Ise, Elena; Arnoldi, Carolin Judith; Schulte-Körne, Gerd

    2014-01-01

    There is growing evidence that children develop orthographic knowledge from the very beginning of literacy acquisition. This study investigated the development of German-speaking children's orthographic knowledge with a nonword choice task. One nonword in each pair contained a frequent consonant doublet ("zommul") and the other…

  8. Predicting Expressive Vocabulary Acquisition in Children with Intellectual Disabilities: A 2-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Vandereet, Joke; Maes, Bea; Lembrechts, Dirk; Zink, Inge

    2010-01-01

    Purpose: This study's objectives were to describe expressive vocabulary acquisition in children with intellectual disabilities (ID) and to examine specific pre- and early linguistic behaviors used to request and comment, chronological age, cognitive skills, and vocabulary comprehension as predictors of expressive vocabulary. Method: This study…

  9. Psychological resilience in U.S. military veterans: A 2-year, nationally representative prospective cohort study.

    PubMed

    Isaacs, Kayla; Mota, Natalie P; Tsai, Jack; Harpaz-Rotem, Ilan; Cook, Joan M; Kirwin, Paul D; Krystal, John H; Southwick, Steven M; Pietrzak, Robert H

    2017-01-01

    Although many cross-sectional studies have examined the correlates of psychological resilience in U.S. military veterans, few longitudinal studies have identified long-term predictors of resilience in this population. The current prospective cohort study utilized data from a nationally representative sample of 2157 U.S. military veterans who completed web-based surveys in two waves (2011 and 2013) as part of the National Health and Resilience in Veterans Study (NHRVS). Cluster analysis of cumulative lifetime exposure to potentially traumatic events and Wave 2 measures of current symptoms of posttraumatic stress, major depressive, and generalized anxiety disorders was performed to characterize different profiles of current trauma-related psychological symptoms. Different profiles were compared with respect to sociodemographic, clinical, and psychosocial characteristics. A three-group cluster analysis revealed a Control group with low lifetime trauma exposure and low current psychological distress (59.5%), a Resilient group with high lifetime trauma and low current distress (27.4%), and a Distressed group with both high trauma exposure and current distress symptoms (13.1%). These results suggest that the majority of trauma-exposed veterans (67.7%) are psychologically resilient. Compared with the Distressed group, the Resilient group was younger, more likely to be Caucasian, and scored lower on measures of physical health difficulties, past psychiatric history, and substance abuse. Higher levels of emotional stability, extraversion, dispositional gratitude, purpose in life, and altruism, and lower levels of openness to experiences predicted resilient status. Prevention and treatment efforts designed to enhance modifiable factors such as gratitude, sense of purpose, and altruism may help promote resilience in highly trauma-exposed veterans.

  10. Chlorhexidine stabilizes the adhesive interface: a 2 year in vitro study

    PubMed Central

    Breschi, Lorenzo; Mazzoni, Annalisa; Nato, Fernando; Carrilho, Marcela; Visintini, Erika; Tjäderhane, Leo; Ruggeri, Alessandra; Tay, Franklin R; De Stefano Dorigo, Elettra; Pashley, David H

    2013-01-01

    Objectives This study evaluated the role of endogenous dentin MMPs in auto-degradation of collagen fibrils within adhesive-bonded interfaces. The null hypotheses tested were that adhesive blends or chlorhexidine digluconate (CHX) application does not modify dentin MMPs activity and that CHX used as therapeutic primer does not improve the stability of adhesive interfaces over time. Methods Zymograms of protein extracts from human dentin powder incubated with Adper Scotchbond 1XT (SB1XT) on untreated or 0.2–2% CHX treated dentin were obtained to assay dentin MMPs activity. Microtensile bond strength and interfacial nanoleakage expression of SB1XT bonded interfaces (with or without CHX pre-treatment for 30s on the etched surface) were analyzed immediately and after 2 yr of storage in artificial saliva at 37°C. Results Zymograms showed that application of SB1XT to human dentin powder increases MMP-2 activity, while CHX pre-treatment inhibited all dentin gelatinolytic activity, irrespective from the tested concentration. CHX significantly lowered the loss of bond strength and nanoleakage seen in acid-etched resin-bonded dentin artificially aged for 2 yr. Significance The study demonstrates the active role of SB1XT in dentin MMP-2 activation and the efficacy of CHX inhibition of MMPs even if used at low concentration (0.2%). PMID:20045177

  11. Involvement in bullying and suicidal ideation in middle adolescence: a 2-year follow-up study.

    PubMed

    Heikkilä, Hanna-Kaisa; Väänänen, Juha; Helminen, Mika; Fröjd, Sari; Marttunen, Mauri; Kaltiala-Heino, Riittakerttu

    2013-02-01

    The objective of the study was to ascertain whether involvement in bullying increases the risk for subsequent suicidal ideation. A total of 2,070 Finnish girls and boys aged 15 were surveyed in the ninth grade (age 15) in schools, and followed up 2 years later in the Adolescent Mental Health Cohort Study. Involvement in bullying was elicited at age 15 by two questions focusing on being a bully and being a victim of bullying. Suicidal ideation was elicited by one item of the short Beck Depression Inventory at age 17. Baseline depressive symptoms and externalizing symptoms, age and sex were controlled for. Statistical analyses were carried out using cross-tabulations with Chi-square/Fisher's exact test and logistic regression. Suicidal ideation at age 17 was 3-4 times more prevalent among those who had been involved in bullying at age 15 than among those not involved. Suicidal ideation at age 17 was most prevalent among former victims of bullying. Being a victim of bullying at age 15 continued to predict subsequent suicidal ideation when depressive and externalizing symptoms were controlled for. Being a bully at age 15 also persisted as borderline significantly predictive of suicidal ideation when baseline symptoms were controlled for. Findings indicate adolescent victims and perpetrators of bullying alike are at long-term risk for suicidal ideation.

  12. Mineral trioxide aggregate as pulp capping agent for primary teeth pulpotomy: 2 year follow up study.

    PubMed

    Subramaniam, Priya; Konde, Sapna; Mathew, Somy; Sugnani, Sony

    2009-01-01

    The aim of the present study was to clinically and radiographically evaluate Mineral Trioxide Aggregate (MTA) as an agent for pulpotomy in primary teeth and to compare it with that of formocresol (FC) pulpotomy. Nineteen children between the ages of 6 to 8 years with 40 carious primary molars were treated with pulpotomy using either FC or MTA. All the molars were evaluated clinically and radiographically at regular intervals over a twenty four month period. The observations were tabulated and statistically analyzed. Eighty five percent success was observed with FC pulpotomy whereas MTA showed 95% success. MTA showed a higher clinical and radiographic success rate than FC. MTA may be a favorable material for pulpotomy in primary teeth whose pulps have been compromised by a carious or mechanical pulp exposure.

  13. A longitudinal study of cryptosporidiosis in dairy cattle from birth to 2 years of age.

    PubMed

    Santín, Mónica; Trout, James M; Fayer, Ronald

    2008-08-01

    Fecal specimens were collected from 30 calves from birth to 24 months of age at a dairy farm in Maryland to determine the prevalence and age distribution of Cryptosporidium species/genotypes. After centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy and polymerase chain reaction (PCR). Fragments of the SSU-rDNA gene amplified by PCR were purified and PCR products were sequenced. All 30 calves shed Cryptosporidium oocysts at some time during the 24 months of the study. Of 990 specimens, 190 were Cryptosporidium-positive (19.2%). The highest prevalence of infection was at 2 weeks of age when 29 of the 30 calves were excreting oocysts. Prevalence was higher in pre-weaned calves (1-8 weeks of age) (45.8%) than in post-weaned calves (3-12 months of age) (18.5%) and heifers (12-24 months of age) (2.2%). Sequence data for 190 PCR-positive specimens identified: C. parvum, C. bovis, the Cryptosporidium deer-like genotype and C. andersoni, with cumulative prevalences of 100, 80, 60, and 3.3%, respectively. C. parvum constituted 97% of infections in pre-weaned calves but only 4% and 0% of infections in post-weaned calves and heifers, respectively. All C. parvum GP60 nucleotide sequences were subtype IIaA15G2R1.

  14. Psychiatric disorders in children with Prader-Willi syndrome-Results of a 2-year longitudinal study.

    PubMed

    Lo, S T; Collin, P J L; Hokken-Koelega, A C S

    2015-05-01

    Psychiatric disorders such as psychosis are highly prevalent in adults with Prader-Willi syndrome (PWS). However, knowledge about the presence and progression of psychiatric disorders in children with PWS is very limited. Sixty-one children with PWS aged 7-17 years were tested using the Diagnostic Interview Schedule for Children (DISC) and Compulsive Behaviour Checklist (CBC), and 38/61 were retested after 2 years. Prevalence of psychiatric disorders and the association with age, gender, genetic subtype, and total IQ were assessed. In addition, occurrence and characteristics of compulsions were determined. Prior to the study, two boys were known with psychotic symptoms and treated with antipsychotics. At baseline, none scored positive for psychotic disorder. During the follow-up, only one boy with known psychotic symptoms required a dose adjustment of his antipsychotic medication. After 2 years, none of the children had a psychotic disorder according to the DISC. Oppositional defiant disorder (ODD) was the most common diagnosis and present in 20% of children with PWS, and this was not associated with age (β = -0.081, P = 0.546), gender (β = 0.013, P = 0.923), genetic subtype (β = -0.073, P = 0.584), or total IQ (β = -0.150, P = 0.267). The most common compulsions were hoarding and fixed hygiene sequences. In our large group of 61 children with PWS, the majority had no psychotic disorder and no progression was found during 2-year follow-up. ODD was present in 20% of children. No changes in the prevalence of psychiatric disorders were found during the 2-year follow-up study and genetic subtype was not related to psychosis, depression, or ODD.

  15. Conducting Simulation Studies in Psychometrics

    ERIC Educational Resources Information Center

    Feinberg, Richard A.; Rubright, Jonathan D.

    2016-01-01

    Simulation studies are fundamental to psychometric discourse and play a crucial role in operational and academic research. Yet, resources for psychometricians interested in conducting simulations are scarce. This Instructional Topics in Educational Measurement Series (ITEMS) module is meant to address this deficiency by providing a comprehensive…

  16. Bioconversion study conducted by JPL

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J.

    1978-01-01

    The Jet Propulsion Laboratory (JPL) of Caltech conducted a study of bioconversion as a means of identifying the role of biomass for meeting the national energy fuel and chemical requirements and the role and means for JPL-Caltech involvement in bioconversion. The bioconversion study included the following categories; biomass sources, chemicals from biomass, thermochemical conversion of biomass to fuels, biological conversion of biomass to fuels and chemicals, and basic bioconversion sciences. A detailed review is included of the bioconversion fields cited with specific conclusions and recommendations given for future research and development and overall biomass system engineering and economic studies.

  17. Association between the high-dose use of benzodiazepines and rehospitalization in patients with schizophrenia: a 2-year naturalistic study

    PubMed Central

    Takita, Yukika; Takaesu, Yoshikazu; Ono, Kotaro; Futenma, Kunihiro; Shimura, Akiyoshi; Murakoshi, Akiko; Komada, Yoko; Inoue, Yuichi; Inoue, Takeshi

    2016-01-01

    Background High-dose use of benzodiazepines (BZPs) reportedly causes adverse effects on cognitive function and quality of life in patients with schizophrenia. However, effects of BZPs on the clinical course of schizophrenia have not been clarified. This study was set out to investigate the association between BZPs and rehospitalization of patients with schizophrenia. Methods In this retrospective study, patients with schizophrenia who were discharged from Tokyo Medical University Hospital between January 2009 and February 2012 were eligible as subjects. One hundred and eight patients who continued treatment for >2 years after hospital discharge were included in this study. Clinical characteristics, doses of prescribed medication such as BZPs and antipsychotics, and Global Assessment of Functioning scores at discharge were investigated. The primary outcome was rehospitalization of patients for any reason. Results In a total of 108 subjects with schizophrenia, 44 subjects (40.7%) experienced rehospitalization during the 2-year study period. A multivariate analysis by the Cox proportional hazards model revealed that low educational history (hazard ratio =2.43, P=0.032), younger onset age of schizophrenia (hazard ratio =2.10, P=0.021), and higher diazepam-equivalent dose (hazard ratio =6.53, P=0.011) were significantly associated with the time to rehospitalization after hospital discharge. Conclusion The results of this study suggest that high-dose use of BZPs at discharge in patients with schizophrenia might be associated with a shorter time to rehospitalization. PMID:28008260

  18. The Auckland Cataract Study: 2 year postoperative assessment of aspects of clinical, visual, corneal topographic and satisfaction outcomes

    PubMed Central

    Thompson, A M; Sachdev, N; Wong, T; Riley, A F; Grupcheva, C N; McGhee, C N

    2004-01-01

    Aim: To assess clinical, visual, computerised corneal topographic, and subjective satisfaction with visual acuity, in a cohort of subjects 2 years after phacoemulsification surgery in a public hospital in New Zealand. Methods: Prospective study of a representative sample of 97 subjects (20%) randomly selected from 480 subjects in the original Auckland Cataract Study (ACS) cohort. The clinical assessment protocol was identical to the ACS and included an extensive questionnaire to enable direct comparisons to be made between the two groups. Results: The study population was predominantly female (66%) with a mean age of 76.3 (SD 9.9) years. New systemic and ocular disease affected 18.4% and 10.3% of subjects respectively, and 10.3% required referral to either a general practitioner (2.1%) or ophthalmologist (8.2%). Mean best spectacle corrected visual acuity (BSCVA) was 0.2 (0.2) logMAR units (6/9 Snellen equivalent), with mean spherical equivalent −0.37 (1.01) dioptres (D) and astigmatism −1.07 (0.70) D 2 years postoperatively, compared to mean BSCVA 0.1 (0.2) logMAR units (6/7.5 Snellen equivalent), spherical equivalent −0.59 (1.07) D, and astigmatism −1.14 (0.77) D 4 weeks after surgery. 94.9% of subjects retained a BSCVA of 6/12 or better, irrespective of pre-existing ocular disease. The overall posterior capsule opacification (PCO) rate was 20.4% and this was visually insignificant in all but 3.1% of eyes that had already undergone Nd:YAG posterior capsulotomy. Orbscan II elevation technology demonstrated corneal stability 2 years after uncomplicated phacoemulsification. Although corneal astigmatism was eliminated in approximately half of the subjects 1 month postoperatively, astigmatism showed a tendency to regress towards the preoperative level with local corneal thickening at the site of incision 2 years after cataract surgery. Of fellow eyes, 61.2% had undergone cataract surgery. Overall, 75.3% of subjects were moderately to very satisfied with their

  19. NOAA's hydrolab conducts reef studies

    NASA Astrophysics Data System (ADS)

    This summer, scuba-diving scientists operating from Hydrolab, NOAA's undersea laboratory, are carrying out four experiments aimed at producing better management of coral reefs and their fishery resources. Hydrolab is located at a depth of 50 feet, near the mouth of the Salt River, off St. Croix, U.S. Virgin Islands. The lab houses four scientists for up to 2 weeks at a time, permitting them to swim out into the water to conduct research. The projects make use of both the natural coral reef near Hydrolab and the nearby artificial reef constructed for comparison studies.

  20. Randomized Trial of a Family-Centered Approach to the Prevention of Early Conduct Problems: 2-Year Effects of the Family Check-Up in Early Childhood

    ERIC Educational Resources Information Center

    Shaw, Daniel S.; Dishion, Thomas J.; Supplee, Lauren; Gardner, Frances; Arnds, Karin

    2006-01-01

    Despite recent research indicating that 1 of the pivotal times for identifying pathways to early conduct problems is the toddler period, few family-based preventive interventions have been specifically designed to modify child disruptive behavior during this age period. This randomized trial tested the effectiveness of the Family Check-Up in…

  1. Iron intakes and status of 2-year-old children in the Cork BASELINE Birth Cohort Study.

    PubMed

    McCarthy, Elaine K; Ní Chaoimh, Carol; O'B Hourihane, Jonathan; Kenny, Louise C; Irvine, Alan D; Murray, Deirdre M; Kiely, Mairead

    2016-08-09

    Young children are at risk of iron deficiency and subsequent anaemia, resulting in long-term consequences for cognitive, motor and behavioural development. This study aimed to describe the iron intakes, status and determinants of status in 2-year-old children. Data were collected prospectively in the mother-child Cork BASELINE Birth Cohort Study from 15 weeks' gestation throughout early childhood. At the 24-month assessment, serum ferritin, haemoglobin and mean corpuscular volume were measured, and food/nutrient intake data were collected using a 2-day weighed food diary. Iron status was assessed in 729 children (median [IQR] age: 2.1 [2.1, 2.2] years) and 468 completed a food diary. From the food diary, mean (SD) iron intakes were 6.8 (2.6) mg/day and 30% had intakes < UK Estimated Average Requirement (5.3 mg/day). Using WHO definitions, iron deficiency was observed in 4.6% (n = 31) and iron deficiency anaemia in five children (1.0%). Following an iron series workup, five more children were diagnosed with iron deficiency anaemia. Twenty-one per cent had ferritin concentrations <15 µg/L. Inadequate iron intakes (OR [95% CI]: 1.94 [1.09, 3.48]) and unmodified cows' milk intakes ≥ 400 mL/day (1.95 [1.07, 3.56]) increased the risk of low iron status. Iron-fortified formula consumption was associated with decreased risk (0.21 [0.11, 0.41] P < 0.05). In this, the largest study in toddlers in Europe, a lower prevalence of low iron status was observed than in previous reports. Compliance with dietary recommendations to limit cows' milk intakes in young children and consumption of iron-fortified products appears to have contributed to improved iron status at two years.

  2. Quantitative sensory tests before and 1(1/2) years after orthognathic surgery: a cross-sectional study.

    PubMed

    Baad-Hansen, L; Arima, T; Arendt-Nielsen, L; Neumann-Jensen, B; Svensson, P

    2010-05-01

    Quality control is very important in relation to invasive and lengthy treatments, such as integrated orthodontic and surgical correction of dentofacial deformities. The aim of this cross-sectional study was to compare self-reported somatosensory disturbances and quantitative sensory testing (QST) findings between two groups of patients and a healthy control group (n = 24); one group (n = 21) scheduled for bimaxillary orthognathic surgery (BOS) (pre-op) and one group (n = 24) examined 1(1/2) years after BOS (post-op). Self-reported data on pain and somatosensory disturbances were collected, and QST was performed at six trigeminal and one extratrigeminal site. Sensitivity to brush stroke, tactile stimuli, pinprick, two-point-discrimination threshold (2P-DT), pinch pain threshold (PiPT) and pressure pain threshold (PPT) was evaluated. Results were analysed with anovas, Spearman's Correlation, and chi square tests. Eight per cent of post-op patients reported intra-oral, 46% extra-oral, and 46% no somatosensory disturbances. Sensitivity to brush stroke, pinprick and 2P-DT was significantly increased at all examination sites in the post-op patients compared with healthy controls (P < 0.002). Tactile thresholds and PPT did not differ between groups (P > 0.071). Pinch pain threshold were decreased in pre-op patients compared with controls (P < 0.040). Self-reported somatosensory disturbances were not correlated with QST findings. In conclusion; 1(1/2) years after BOS, a large proportion of patients reported somatosensory disturbances and was hypersensitive to mechanical stimuli when compared with pre-op patients and healthy controls. Pre-op patients showed minor somatosensory changes. In addition to patients serving as their own control in prospective studies, a healthy control group and extratrigeminal control sites should be included in future studies.

  3. Disordered eating behaviors and body image in a longitudinal pilot study of adolescent girls: what happens 2 years later?

    PubMed

    Espinoza, Paola; Penelo, Eva; Raich, Rosa M

    2010-01-01

    We assessed the prospective association of risk factors for eating and body image disturbances after a 2-year follow-up in a community sample of Spanish adolescent girls. The participants included 128 Spanish girls aged 12-14, who took part in a 28-month prospective study. Aspects assessed were eating attitudes (Eating Attitudes Test), influence of the body shape model (questionnaire on influences of the aesthetic body shape model), extreme weight-control behaviors (Eating Disorder Examination-Questionnaire), body image (Body Image Questionnaire) and Body Mass Index (BMI). BMI, extreme weight-control behaviors and body image problems emerged as potential predictors of an increase in eating disturbances. An increased influence of the thinness model was significantly associated with reduced body satisfaction and body image problems. Preventive programs are needed to contribute reducing the impact of sociocultural influences with regard to thinness, the use of extreme weight-control behaviors and overweight in adolescents.

  4. Executive functioning correctly classified diagnoses in patients with first-episode psychosis: evidence from a 2-year longitudinal study.

    PubMed

    Peña, Javier; Ojeda, Natalia; Segarra, Rafael; Eguiluz, Jose Ignacio; García, Jon; Gutiérrez, Miguel

    2011-03-01

    Few studies have analysed factors that predict the ultimate clinical diagnosis in first-episode psychosis (FEP), and none has included cognitive factors. Eighty-six FEP patients and 34 healthy controls were recruited and followed up for two years. Positive and negative symptoms, depression, mania, duration of untreated psychosis (DUP), premorbid functioning, functional outcome and neurocognition were assessed over 2 years. Logistic regression models revealed that Wisconsin Card Sorting Test correctly distinguished the patients ultimately diagnosed with schizophrenia (87%) from those with bipolar disorder (80%) and those with other psychoses (85%), for an overall correct-diagnosis rate of 84.4%. The prediction was stable despite the inclusion of clinical and affective symptoms, DUP, clinical impression, and functional outcome scores. Results highlight the importance of reconsidering neurocognition as a diagnostic criterion for psychosis and schizophrenia.

  5. Prospective study of cognitive function in children receiving whole-brain radiotherapy and chemotherapy: 2-year results

    SciTech Connect

    Packer, R.J.; Sutton, L.N.; Atkins, T.E.; Radcliffe, J.; Bunin, G.R.; D'Angio, G.; Siegel, K.R.; Schut, L. )

    1989-05-01

    As survival rates have risen for children with malignant primary brain tumors, so has the concern that many survivors have significant permanent cognitive deficits. Cranial irradiation (CRT) has been implicated as the major cause for cognitive dysfunction. To clarify the etiology, incidence, and severity of intellectual compromise in children with brain tumors after CRT, a prospective study was undertaken comparing the neuropsychological outcome in 18 consecutive children with malignant brain tumors treated with CRT to outcome in 14 children harboring brain tumors in similar sites in the nervous system who had not received CRT. Children with cortical or subcortical brain tumors were not eligible for study. Neuropsychological testing was performed after surgery prior to radiotherapy, after radiotherapy, and at 1- and 2-year intervals thereafter. Children who had received CRT had a mean full-scale intelligence quotient (FSIQ) of 105 at diagnosis which fell to 91 by Year 2. Similar declines were noted in their performance intelligence quotient (IQ) and verbal IQ. After CRT, patients demonstrated a statistically significant decline from baseline in FSIQ (p less than 0.02) and verbal IQ (p less than 0.04). Children who had not received CRT did not demonstrate a fall in any cognitive parameter over time. The decline between baseline testing and testing performed at Year 2 in patients who had CRT was inversely correlated with age (p less than 0.02), as younger children demonstrated the greatest loss of intelligence. Children less than 7 years of age at diagnosis had a mean decline in FSIQ of 25 points 2 years posttreatment. No other clinical parameter correlated with the overall IQ or decline in IQ. After CRT, children demonstrated a wide range of dysfunction including deficits in fine motor, visual-motor, and visual-spatial skills and memory difficulties.

  6. Parental height and child growth from birth to 2 years in the WHO Multicentre Growth Reference Study.

    PubMed

    Garza, Cutberto; Borghi, Elaine; Onyango, Adelheid W; de Onis, Mercedes

    2013-09-01

    Linear growth from birth to 2 years of children enrolled in the World Health Organization Multicentre Growth Reference Study was similar despite substantial parental height differences among the six study sites. Within-site variability in child length attributable to parental height was estimated by repeated measures analysis of variance using generalized linear models. This approach was also used to examine relationships among selected traits (e.g. breastfeeding duration and child morbidity) and linear growth between 6 and 24 months of age. Differences in intergenerational adult heights were evaluated within sites by comparing mid-parental heights (average of the mother's and father's heights) to the children's predicted adult height. Mid-parental height consistently accounted for greater proportions of observed variability in attained child length than did either paternal or maternal height alone. The proportion of variability explained by mid-parental height ranged from 11% in Ghana to 21% in India. The average proportion of between-child variability accounted for by mid-parental height was 16% and the analogous within-child estimate was 6%. In the Norwegian and US samples, no significant differences were observed between mid-parental and children's predicted adult heights. For the other sites, predicted adult heights exceeded mid-parental heights by 6.2-7.8 cm. To the extent that adult height is predicted by height at age 2 years, these results support the expectation that significant community-wide advances in stature are attainable within one generation when care and nutrition approximate international recommendations, notwithstanding adverse conditions likely experienced by the previous generation.

  7. Use of Ergonomic Measures Related to Musculoskeletal Complaints among Construction Workers: A 2-year Follow-up Study

    PubMed Central

    Boschman, Julitta S.; Frings-Dresen, Monique H.W.; van der Molen, Henk F.

    2015-01-01

    Background The physical work demands of construction work can be reduced using ergonomic measures. The aim of this study was to evaluate the use of ergonomic measures related to musculoskeletal disorders (MSDs) among construction workers. Methods A questionnaire was sent at baseline and 2 years later to 1,130 construction workers. We established (1) the proportion of workers reporting an increase in their use of ergonomic measures, (2) the proportion of workers reporting a decrease in MSDs, (3) the relative risk for an increase in the use of ergonomic measures and a decrease in MSDs, and (4) workers' knowledge and opinions about the use of ergonomic measures. Results At follow-up, response rate was 63% (713/1,130). The proportion of workers using ergonomic measures for vertical transport increased (34%, 144/419, p < 0.01); for measures regarding horizontal transport and the positioning of materials, no change was reported. The proportion of workers reporting shoulder complaints decreased (28%, 176/638, p = 0.02). A relationship between the use of ergonomic measures and MSDs was not found; 83% (581/704) of the workers indicated having sufficient knowledge about ergonomic measures. Lightening the physical load was reported to be the main reason for using them. Conclusion Only the use of ergonomic measures for vertical transport increased over a 2-year period. No relationship between the use of ergonomic measures and MSDs was found. Strategies aimed at improving the availability of ergonomic equipment complemented with individualized advice and training in using them might be the required next steps to increase the use of ergonomic measures. PMID:26106507

  8. Effect of Workplace Noise on Hearing Ability in Tile and Ceramic Industry Workers in Iran: A 2-Year Follow-Up Study

    PubMed Central

    Mirmohammadi, Seyyed Jalil; Mehrparvar, Amir Houshang; Mollasadeghi, Abolfazl

    2013-01-01

    Introduction. Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers. Methods. This follow-up study was conducted on 555 workers (totally 1110 ears). Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear. Results. Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%), 49 (8.83%), 22 (3.96%), and 63 (11.35%) subjects in the first and second years of follow-up in the right and left ears, respectively. Conclusions. This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices. PMID:24453922

  9. The Effect of the Father-Child Relationship on the Social Conduct of 2 1/2 Year Old Children in Preschool

    ERIC Educational Resources Information Center

    Burgos, Louis

    2003-01-01

    Our goal is to study the effects of early paternal involvement on a child's socialization. Usually in works concerning the question, we study the father's contribution with questionnaires, we base our evaluation of involvement on the behavior declared by the subject. We have attempted to analyze the affective dimension of this involvement. We have…

  10. A 2-year follow-up study on muscle size and dynamic strength in teenage tennis players.

    PubMed

    Kanehisa, H; Kuno, S; Katsuta, S; Fukunaga, T

    2006-04-01

    Growth trends in the cross-sectional area of the quadriceps femoris (CSA(QF)) and its dynamic strength in 12 teenage tennis players (six boys and six girls), aged from 10.7 to 13.2 years at the onset of the study, were investigated through a 2-year follow-up survey. CSA(QF) values at the three levels (proximal, mid, and distal to the knee joint) and dynamic torques during knee extensions at three pre-set velocities (1.05, 3.14, and 5.24 rad/s) were determined year by year, i.e., three times (T1, T2, and T3), using magnetic resonance imaging and an isokinetic dynamometer, respectively. In both genders, the CSA(QF) values at the three levels tended to increase across the measurement times, with greater gains in the boys than in the girls at the levels mid and distal to the knee joint. Among these changes, only the CSA(QF) at the level proximal to the knee joint significantly increased regardless of changes in both skeletal age and body height. The ratios of torque to the sum of CSA(QF) at the three levels (T/CSA) at 3.14 and 5.24 rad/s for the boys and at 5.24 rad/s for the girls were significantly higher in T2 and T3 than T1. Further, the relative increases in torque and T/CSA values at 3.14 and 5.24 rad/s were greater in the boys than the girls. The findings presented here indicate that young tennis players who are in the earlier stage of adolescence increase the CSA of the QF muscle beyond normally expected growth change at the level proximal to the knee joint and show a predominant development in torque generation capability during high-velocity knee extensions, with a greater gain in boys compared with girls.

  11. A 2-year longitudinal study of eating attitudes, BMI, perfectionism, asceticism and family climate in adolescent girls and their parents.

    PubMed

    Westerberg, J; Edlund, B; Ghaderi, A

    2008-06-01

    The aim of this longitudinal study of 383 Swedish adolescent girls (11 and 13 years old at year 1) and their parents was to examine changes in eating attitudes over a two-year period, and to investigate the predictive value of eating attitudes, perfectionism, asceticism, family climate and body mass index (BMI) for the development of disturbed eating attitudes. The following self-report questionnaires were used: Children's Eating Attitudes test, Eating Attitudes Test, Eating Disorder Inventory for Children, Eating Disorder Inventory 2, I Think I Am and The Family Climate. The frequency of disturbed eating attitudes increased with increased age in the girls. Children's eating attitudes, higher BMI than peers, the girls rating of a less healthy relation to family and their fathers' eating attitudes at year 1 contributed most to the prediction of disturbed eating attitudes for the girls 2 years later. The results suggest that early signs of disturbed eating attitudes and higher BMI than peers may be important predictors for the development of more serious eating disturbances among adolescent girls.

  12. Differences in predictors of traditional and cyber-bullying: a 2-year longitudinal study in Korean school children.

    PubMed

    Yang, Su-Jin; Stewart, Robert; Kim, Jae-Min; Kim, Sung-Wan; Shin, Il-Seon; Dewey, Michael E; Maskey, Sean; Yoon, Jin-Sang

    2013-05-01

    Traditional bullying has received considerable research but the emerging phenomenon of cyber-bullying much less so. Our study aims to investigate environmental and psychological factors associated with traditional and cyber-bullying. In a school-based 2-year prospective survey, information was collected on 1,344 children aged 10 including bullying behavior/experience, depression, anxiety, coping strategies, self-esteem, and psychopathology. Parents reported demographic data, general health, and attention-deficit hyperactivity disorder (ADHD) symptoms. These were investigated in relation to traditional and cyber-bullying perpetration and victimization at age 12. Male gender and depressive symptoms were associated with all types of bullying behavior and experience. Living with a single parent was associated with perpetration of traditional bullying while higher ADHD symptoms were associated with victimization from this. Lower academic achievement and lower self esteem were associated with cyber-bullying perpetration and victimization, and anxiety symptoms with cyber-bullying perpetration. After adjustment, previous bullying perpetration was associated with victimization from cyber-bullying but not other outcomes. Cyber-bullying has differences in predictors from traditional bullying and intervention programmes need to take these into consideration.

  13. Associations between weather conditions and clinical symptoms in patients with hip osteoarthritis: a 2-year cohort study.

    PubMed

    Dorleijn, Desirée M J; Luijsterburg, Pim A J; Burdorf, Alex; Rozendaal, Rianne M; Verhaar, Jan A N; Bos, Pieter K; Bierma-Zeinstra, Sita M A

    2014-04-01

    The goal of this study was to assess whether there is an association between ambient weather conditions and patients' clinical symptoms in patients with hip osteoarthritis (OA). The design was a cohort study with a 2-year follow-up and 3-monthly measurements and prospectively collected data on weather variables. The study population consisted of 222 primary care patients with hip OA. Weather variables included temperature, wind speed, total amount of sun hours, precipitation, barometric pressure, and relative humidity. The primary outcomes were severity of hip pain and hip disability as measured with the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) pain and function subscales. Associations between hip pain and hip disability and the weather variables were assessed using crude and multivariate adjusted linear mixed-model analysis for repeated measurements. On the day of questionnaire completion, mean relative humidity was associated with WOMAC pain (estimate 0.1; 95% confidence interval=0.0-0.2; P=.02). Relative humidity contributed < or = 1% to the explained within-patient variance and between-patient variance of the WOMAC pain score. Mean barometric pressure was associated with WOMAC function (estimate 0.1; 95% confidence interval=0.0-0.1; P=.02). Barometric pressure contributed < or = 1% to the explained within-patient variance and between-patient variance of the WOMAC function score. The other weather variables were not associated with the WOMAC pain or function score. Our results support the general opinion of OA patients that barometric pressure and relative humidity influence perceived OA symptoms. However, the contribution of these weather variables (< or = 1%) to the severity of OA symptoms is not considered to be clinically relevant.

  14. Effects of galantamine in a 2-year, randomized, placebo-controlled study in Alzheimer’s disease

    PubMed Central

    Hager, Klaus; Baseman, Alan S; Nye, Jeffrey S; Brashear, H Robert; Han, John; Sano, Mary; Davis, Bonnie; Richards, Henry M

    2014-01-01

    Background Currently available treatments for Alzheimer’s disease (AD) can produce mild improvements in cognitive function, behavior, and activities of daily living in patients, but their influence on long-term survival is not well established. This study was designed to assess patient survival and drug efficacy following a 2-year galantamine treatment in patients with mild to moderately severe AD. Methods In this multicenter, double-blind study, patients were randomized 1:1 to receive galantamine or placebo. One primary end point was safety; mortality was assessed. An independent Data Safety Monitoring Board monitored mortality for the total deaths reaching prespecified numbers, using a time-to-event method and a Cox-regression model. The primary efficacy end point was cognitive change from baseline to month 24, as measured by the Mini-Mental State Examination (MMSE) score, analyzed using intent-to-treat analysis with the ‘last observation carried forward’ approach, in an analysis of covariance model. Results In all, 1,024 galantamine- and 1,021 placebo-treated patients received study drug, with mean age ~73 years, and mean (standard deviation [SD]) baseline MMSE score of 19 (4.08). A total of 32% of patients (661/2,045) completed the study, 27% (554/2,045) withdrew, and 41% (830/2,045) did not complete the study and were discontinued due to a Data Safety Monitoring Board-recommended early study termination. The mortality rate was significantly lower in the galantamine group versus placebo (hazard ratio [HR] =0.58; 95% confidence interval [CI]: 0.37; 0.89) (P=0.011). Cognitive impairment, based on the mean (SD) change in MMSE scores from baseline to month 24, significantly worsened in the placebo (−2.14 [4.34]) compared with the galantamine group (−1.41 [4.05]) (P<0.001). Functional impairment, based on mean (SD) change in the Disability Assessment in Dementia score (secondary end point), at month 24 significantly worsened in the placebo (−10.81 [18

  15. Determinants of “return to work in good health” among workers with back pain who consult in primary care settings: a 2-year prospective study

    PubMed Central

    Bourbonnais, Renée; Frémont, Pierre; Rossignol, Michel; Stock, Susan R.; Nouwen, Arie; Larocque, Isabelle; Demers, Eric

    2006-01-01

    Many factors have been linked to return to work after a back pain episode, but our understanding of this phenomenon is limited and cross-sectional dichotomous indices of return to work are not valid measures of this construct. To describe the course of “return to work in good health” (RWGH—a composite index of back pain outcome) among workers who consulted in primary care settings for back pain and identify its determinants, a 2-year prospective study was conducted. Subjects (n = 1,007, 68.4%) were workers who consulted in primary care settings of the Quebec City area for a nonspecific back pain. They completed five telephone interviews over 2 years (follow-up = 86%). Analyses linking baseline variables with 2-year outcome were conducted with polytomous logistic regression. The proportion of “success” in RWGH increased from 18% at 6 weeks to 57% at 2 years. In women, persistent pain, pain radiating to extremities, increasing job seniority, not having a unionized job, feeling that the physician did listen carefully and increasing fear-avoidance beliefs towards work and activity were determinants of “failure” in RWGH. In men, decreasing age, cigarette smoking, poor self-reported health status, pain in the thoracic area, previous back surgeries, a non-compensated injury, high pain levels, belief that job is below qualifications, likelihood of losing job, job status, satisfaction with health services and fear-avoidance beliefs towards work were all significant. RWGH among workers with back pain receives multiple influences, especially among men. In both genders, however, fear-avoidance beliefs about work are associated with failure and high self-efficacy is associated with success. PMID:16868783

  16. Minimally Invasive Periodontal Treatment Using the Er,Cr: YSGG Laser. A 2-year Retrospective Preliminary Clinical Study

    PubMed Central

    Dyer, Bret; Sung, Eric C.

    2012-01-01

    Minimally invasive surgery (MIS) using the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser (Waterlase MD, Biolase, Irvine, CA) to treat moderate to advanced periodontal disease is presented as an alternative to conventional therapies. To date, there are few short- or long-term studies to demonstrate the effects of this laser in treating and maintaining periodontal health. Electronic clinical records from 16 patients – total of 126 teeth, with pocket depths ranging from 4 mm to 9 mm – were treated with the same protocol using the Er,Cr:YSGG laser. The mean baseline probing depths (PD) were 5 mm and clinical attachment levels (CAL) were 5 mm in the 4 - 6 mm pretreated laser group. The mean baseline probing depths were 7.5 and 7.6 mm for PD and CAL respectfully in the 7 – 9 mm pretreatment laser group. At the 2 year mark, the average PD was 3.2 ± 1.1 mm for the 4-6 mm pocket group and the 7-9 mm pocket group had a mean PD of 3.7 ± 1.2 mm. mean CAL was 3.1 ± 1.1 mm for the 4-6 mm group and 3.6 ± 1.2 for the 7-9 mm group with an overall reduction of 1.9 mm and 4.0 mm respectively. At one and two years, both groups remained stable with PD comparable to the three-month gains. The CAL measurements at one and two years were also comparable to the three-month gains. PMID:22615717

  17. Trajectories of CKD-MBD biochemical parameters over a 2-year period following diagnosis of secondary hyperparathyroidism: a pharmacoepidemiological study

    PubMed Central

    Filipozzi, Pierre; Ayav, Carole; Ngueyon Sime, Willy; Laurain, Emmanuelle; Kessler, Michèle; Brunaud, Laurent; Frimat, Luc

    2017-01-01

    Objectives To define groups of patients according to the changes of biochemical parameters, that is, serum calcium, phosphate and parathyroid hormone (PTH), over a 2-year follow-up period using group-based multi-trajectory modeling (GBMM) among a cohort of dialysis patients with newly diagnosed secondary hyperparathyroidism (SHPT) (ie, PTH≥500 ng/L for the first time) and to compare their patient characteristics and treatments. Design Pharmacoepidemiological study. Setting In the 12 dialysis units located in the French region of Lorraine. Participants A total of 269 dialysis patients with newly diagnosed SHPT were prospectively included from December 2009 to May 2012 and followed-up for 2 years. Results We identified four distinct trajectory groups: ‘rapid PTH drop’ experiencing a rapid and sharp decrease (over weeks) in PTH level associated with decreasing phosphate level within normal range (n=34; 12.7%), ‘gradual PTH decrease’ experiencing a gradual and continuous decrease (over months) in PTH level and maintaining phosphate at a middle level throughout the study (n=98; 36.4%), ‘slow PTH decrease with high phosphate’ experiencing a slow decrease in PTH level associated with a relatively high phosphate level (n=105; 39.0%) and ‘uncontrolled SHPT’ with high levels of PTH and phosphate throughout the study (n=32; 11.9%). Patients in the ‘uncontrolled SHPT’ group were significantly (p<0.00001) younger than patients in other groups. Kidney Disease Improving Global Outcomes (KDIGO) targets for PTH, phosphate and calcium were reached simultaneously for 14.9% of patients at baseline and 16.7% at the end of the study. Patients were given cinacalcet more frequently at months 3 and 6 in the ‘rapid PTH drop’ and at month 24 in the ‘uncontrolled SHPT’ groups. Conclusions Over 2 years following a new SHPT diagnosis, a younger age and a higher rate of alkaline phosphatase were associated to a continuous uncontrolled SHPT. Patients with the

  18. Conducting and Reporting Case Studies.

    ERIC Educational Resources Information Center

    Lichtman, Merilyn; Taylor, Satomi Izumi

    Issues and elements of case study research are explored and illustrated with the example of a case study of a kindergarten in a suburb of Tokyo (Japan). Case study research is a type of qualitative research that concentrates on a single unit or entity, with boundaries established by the researcher. The case is an example drawn from a larger class,…

  19. Conducting pilot and feasibility studies.

    PubMed

    Cope, Diane G

    2015-03-01

    Planning a well-designed research study can be tedious and laborious work. However, this process is critical and ultimately can produce valid, reliable study findings. Designing a large-scale randomized, controlled trial (RCT)-the gold standard in quantitative research-can be even more challenging. Even the most well-planned study potentially can result in issues with research procedures and design, such as recruitment, retention, or methodology. One strategy that may facilitate sound study design is the completion of a pilot or feasibility study prior to the initiation of a larger-scale trial. This article will discuss pilot and feasibility studies, their advantages and disadvantages, and implications for oncology nursing research. 
.

  20. Anterior cervical fusion with interbody cage containing beta-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up.

    PubMed

    Dai, Li-Yang; Jiang, Lei-Sheng

    2008-05-01

    A variety of bone graft substitutes, interbody cages, and anterior plates have been used in cervical interbody fusion, but no controlled study was conducted on the clinical performance of beta-tricalcium phosphate (beta-TCP) and the effect of supplemented anterior plate fixation. The objective of this prospective, randomized clinical study was to evaluate the effectiveness of implanting interbody fusion cage containing beta-TCP for the treatment of cervical radiculopathy and/or myelopathy, and the fusion rates and outcomes in patients with or without randomly assigned plate fixation. Sixty-two patients with cervical radiculopathy and/or myelopathy due to soft disc herniation or spondylosis were treated with one- or two-level discectomy and fusion with interbody cages containing beta-TCP. They were randomly assigned to receive supplemented anterior plate (n = 33) or not (n = 29). The patients were followed up for 2 years postoperatively. The radiological and clinical outcomes were assessed during a 2-year follow-up. The results showed that the fusion rate (75.0%) 3 months after surgery in patients treated without anterior cervical plating was significantly lower than that (97.9%) with plate fixation (P < 0.05), but successful bone fusion was achieved in all patients of both groups at 6-month follow-up assessment. Patients treated without anterior plate fixation had 11 of 52 (19.2%) cage subsidence at last follow-up. No difference (P > 0.05) was found regarding improvement in spinal curvature as well as neck and arm pain, and recovery rate of JOA score at all time intervals between the two groups. Based on the findings of this study, interbody fusion cage containing beta-TCP following one- or two-level discectomy proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Supplemented anterior plate fixation can promote interbody fusion and prevent cage subsidence but do not improve the 2-year outcome when compared with those treated

  1. DROPOUT STUDIES, DESIGN AND CONDUCT.

    ERIC Educational Resources Information Center

    SCHRIEBER, DANIEL; AND OTHERS

    ALTHOUGH THE DROPOUT PROBLEM IS ONE OF GREAT CONCERN AT BOTH LOCAL AND NATIONAL LEVELS, IT IS READILY APPARENT THAT THE PROBLEM IS NOT THE SAME EVERYWHERE IN THE COUNTRY. DROPOUT RATES VARY CONSIDERABLY FROM ONE COMMUNITY TO ANOTHER, AND EVEN DIFFER BETWEEN HIGH SCHOOLS IN THE SAME SCHOOL SYSTEM. LIMITATIONS IN PREVIOUS STUDIES OF THE PROBLEM HAVE…

  2. A 2-Year, Phase IV, Multicentre, Observational Study of Ranibizumab 0.5 mg in Patients with Neovascular Age-Related Macular Degeneration in Routine Clinical Practice: The EPICOHORT Study.

    PubMed

    Pagliarini, Sergio; Beatty, Stephen; Lipkova, Blandina; Perez-Salvador Garcia, Eduardo; Reynders, Stefaan; Gekkieva, Margarita; Si Bouazza, Abdelkader; Pilz, Stefan

    2014-01-01

    Purpose. To assess the safety profile of ranibizumab 0.5 mg in patients with neovascular age-related macular degeneration (nAMD) in routine clinical practice. Methods. This 2-year, multicentre, observational study was conducted to capture real-world early practice and outcomes across Europe, shortly after European licensing of ranibizumab for nAMD. Being observational in nature, the study did not impose diagnostic/therapeutic interventions/visit schedule. Patients were to be treated as per the EU summary of product characteristics (SmPC) in effect during the study. Key outcome measures were incidence of selected adverse events (AEs), treatment exposure, bilateral treatment, compliance to the EU SmPC, and best-corrected visual acuity (BCVA) over 2 years. Results. 755 of 770 patients received treatment. Ranibizumab was generally well tolerated with low incidence of selected AEs (0%-1.9%). Patients received 6.2 (mean) injections and 133 patients received bilateral treatment over 2 years. Protocol deviation to treatment compliance was reported in majority of patients. The observed decline in mean BCVA (Month 12, +1.5; Month 24, -1.3 letters) may be associated with undertreatment as suggested by BCVA subgroup analysis. Conclusion. The EPICOHORT study conducted in routine clinical practice reinforces the well-established safety profile of ranibizumab in nAMD. In early European practice it appeared that the nAMD patients were undertreated.

  3. Conducting a wind sensing study

    NASA Technical Reports Server (NTRS)

    Byer, R. L.

    1985-01-01

    Signal-to-noise requirements, and how signal-to-noise determines wind velocity measurement accuracy were studied. A Nd:YAG-based system was found to be competitive with a CO2-based system. Hardware was developed for a coherent Nd:YAG LIDAR system, and is being integrated into a functioning system. A diode-pumped monolithic rod laser to be used as a reference oscillator, a high-power, single-mode ring laser, for use as a master oscillator, and a high-gain, multipass amplifier were constructed.

  4. Developmental milestones record - 2 years

    MedlinePlus

    Growth milestones for children - 2 years; Normal childhood growth milestones - 2 years; Childhood growth milestones - 2 years ... a cause for concern if not seen by 2 years.) Can run with better coordination . (May still ...

  5. Quality of life after laparoscopic gastric banding: Prospective study (152 cases) with a follow-up of 2 years.

    PubMed

    Champault, Axèle; Duwat, Olivier; Polliand, Claude; Rizk, Nabil; Champault, Gérard G

    2006-06-01

    To evaluate influence of laparoscopic gastric banding (LGB) on quality of life (QOL) in patients with morbid obesity. Laparoscopic adjustable gastric banding is a popular bariatric operation in Europe. The objectives of surgical therapy in patients with morbid obesity are reduction of body weight, and a positive influence on the obesity-related comorbidity as well the concomitant psychologic and social restrictions of these patients. In a prospective clinical trial, development of the individual patient QOL was analyzed, after LGB in patients with morbid obesity. From October 1999 to January 2001, 152 patients [119 women, 33 men, mean age 38.4 y (range 24 to 62), mean body mass index 44.3 (range 38 to 63)] underwent evaluation for LGB according the following protocol: history of obesity; concise counseling of patients and relative on nonsurgical treatment alternatives, risk of surgery, psychologic testing, questionnaire for eating habits, necessity of lifestyle change after surgery; medical evaluation including endocrinologic and nutritionist work-up, upper GI endoscopy, evaluation of QOL using the Gastro Intestinal Quality of Life Index (GIQLI). Decision for surgery was a multidisciplinary consensus. This group was follow-up at least 2 years, focusing on weight loss and QOL. Mean operative time was 82 minutes; mean hospital stay was 2.3 days and the mean follow-up period was 34 months. The BMI dropped from 44.3 to 29.6 kg/m and all comorbid conditions improved markedly: diabetes melitus resolved in 71% of the patients, hypertension in 33%, and sleep apnea in 90%. However, 26 patients (17%) had late complications requiring reoperation. Preoperative global GIQLI score was 95 (range 56 to 140), significant different of the healthy volunteers score (120) (70 to 140) P < 0.001. Correlated with weight loss (percentage loss of overweight and BMI), the global score of the group increased to 100 at 3 months, 104 at 6, 111 at 1 year to reach 119 at 2 years which is no

  6. Towards a validation of a cellular biomarker suite in native and transplanted zebra mussels: a 2-year integrative field study of seasonal and pollution-induced variations.

    PubMed

    Guerlet, Edwige; Ledy, Karine; Meyer, Antoinette; Giambérini, Laure

    2007-03-30

    Two of the questions raised in the validation process of biomarkers are their relevance in the identification and discrimination of environmental perturbations, and the influence of seasonal factors on these biological endpoints. Determining the advantages and restrictions associated with the use of native or transplanted animals and comparing their responses is also needed. To obtain this information, a 2-year integrative field study was conducted in the vicinity of a nuclear power plant in northeastern France. A station was located in the reservoir receiving the cooling waters of the plant, and two other sites were studied 2 km upstream and 5 km downstream from the reservoir's discharge in the Moselle river. Elevated temperatures, copper contamination and a 1.4-fold-concentration factor of dissolved salts affected water quality of the reservoir. Native and transplanted zebra mussels (Dreissena polymorpha) were collected monthly and their digestive glands were processed for histochemical determinations of the lysosomal and peroxisomal systems and of the lipofuscin and neutral lipid contents. The responses were quantified using automated image analysis and stereology. Apart from neutral lipid contents, there were no systematic seasonal patterns in mussel populations or from 1 year to another. Principal Component Analyses showed a general higher discrimination potential of biological responses in transplanted organisms compared to native ones. They also pointed out the relationships between the cellular and physiological markers and abiotic factors. The present multiple biomarker integrative approach in transplanted D. polymorpha brings promising elements in their validation process as relevant biomonitoring tools.

  7. Iron-Folic Acid Supplementation During Pregnancy Reduces the Risk of Stunting in Children Less Than 2 Years of Age: A Retrospective Cohort Study from Nepal

    PubMed Central

    Nisar, Yasir Bin; Dibley, Michael J.; Aguayo, Victor M.

    2016-01-01

    The aim of the study was to investigate the effect of antenatal iron-folic acid (IFA) supplementation on child stunting in Nepalese children age <2 years. A retrospective cohort study design was used, in which a pooled cohort of 5235 most recent live births 2 years prior to interview from three Nepal Demographic and Health Surveys (2001, 2006 and 2011) was analysed. The primary outcome was stunting in children age <2 years. The main exposure variable was antenatal IFA supplementation. Multivariate Poisson regression analysis was performed. In our sample, 31% and 10% of Nepalese children age <2 years were stunted and severely stunted, respectively. The adjusted relative risk of being stunted was 14% lower in children whose mothers used IFA supplements compared to those whose mothers did not use (aRR = 0.86, 95% CI = 0.77–0.97). Additionally, the adjusted relative risk of being stunted was significantly reduced by 23% when antenatal IFA supplementation was started ≤6 months with ≥90 IFA supplements used during pregnancy (aRR = 0.77, 95% CI = 0.64–0.92). Antenatal IFA supplementation significantly reduced the risk of stunting in Nepalese children age <2 years. The greatest impact on the risk reduction of child stunting was when IFA supplements were started ≤6 months with ≥90 supplements were used. PMID:26828515

  8. Iron-Folic Acid Supplementation During Pregnancy Reduces the Risk of Stunting in Children Less Than 2 Years of Age: A Retrospective Cohort Study from Nepal.

    PubMed

    Nisar, Yasir Bin; Dibley, Michael J; Aguayo, Victor M

    2016-01-27

    The aim of the study was to investigate the effect of antenatal iron-folic acid (IFA) supplementation on child stunting in Nepalese children age <2 years. A retrospective cohort study design was used, in which a pooled cohort of 5235 most recent live births 2 years prior to interview from three Nepal Demographic and Health Surveys (2001, 2006 and 2011) was analysed. The primary outcome was stunting in children age <2 years. The main exposure variable was antenatal IFA supplementation. Multivariate Poisson regression analysis was performed. In our sample, 31% and 10% of Nepalese children age <2 years were stunted and severely stunted, respectively. The adjusted relative risk of being stunted was 14% lower in children whose mothers used IFA supplements compared to those whose mothers did not use (aRR = 0.86, 95% CI = 0.77-0.97). Additionally, the adjusted relative risk of being stunted was significantly reduced by 23% when antenatal IFA supplementation was started ≤6 months with ≥90 IFA supplements used during pregnancy (aRR = 0.77, 95% CI = 0.64-0.92). Antenatal IFA supplementation significantly reduced the risk of stunting in Nepalese children age <2 years. The greatest impact on the risk reduction of child stunting was when IFA supplements were started ≤6 months with ≥90 supplements were used.

  9. Plantar Pressure Changes and Correlating Risk Factors in Chinese Patients with Type 2 Diabetes: Preliminary 2-year Results of a Prospective Study

    PubMed Central

    Qiu, Xuan; Tian, De-Hu; Han, Chang-Ling; Chen, Wei; Wang, Zhan-Jian; Mu, Zhen-Yun; Liu, Kuan-Zhi

    2015-01-01

    Background: Plantar pressure serves as a key factor for predicting ulceration in the feet of diabetes patients. We designed this study to analyze plantar pressure changes and correlating risk factors in Chinese patients with type 2 diabetes. Methods: We recruited 65 patients with type 2 diabetes. They were invited to participate in the second wave 2 years later. The patients completed identical examinations at the baseline point and 2 years later. We obtained maximum force, maximum pressure, impulse, pressure-time integral, and loading rate values from 10 foot regions. We collected data on six history-based variables, six anthropometric variables, and four metabolic variables of the patients. Results: Over the course of the study, significant plantar pressure increases in some forefoot portions were identified (P < 0.05), especially in the second to forth metatarsal heads. Decreases in heel impulse and pressure-time integral levels were also found (P < 0.05). Plantar pressure parameters increased with body mass index (BMI) levels. Hemoglobin A1c (HbA1c) changes were positively correlated with maximum force (β = 0.364, P = 0.001) and maximum pressure (β = 0.366, P = 0.002) changes in the first metatarsal head. Cholesterol changes were positively correlated with impulse changes in the lateral portion of the heel (β = 0.179, P = 0.072) and pressure-time integral changes in the second metatarsal head (β = 0.236, P = 0.020). Ankle-brachial index (ABI) changes were positively correlated with maximum force changes in the first metatarsal head (β = 0.137, P = 0.048). Neuropathy symptom score (NSS) and common peroneal nerve sensory nerve conduction velocity (SCV) changes were positively correlated with some plantar pressure changes. In addition, plantar pressure changes had a correlation with the appearance of infections, blisters (β = 0.244, P = 0.014), and calluses over the course of the study. Conclusions: We should pay attention to the BMI, HbA1c, cholesterol, ABI

  10. Genetic profiles of Shiga toxin and intimin genes found in stool broth cultures: a 2-year reference laboratory study.

    PubMed

    Michel, Pierre A; Kase, Julie A

    2009-10-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) are associated with potentially serious illness in humans. STEC detection is often based on the presence of Stxs, Stx(1) and/or Stx(2), and intimin, encoded by the eae gene. A 2-year collection of stool broth cultures was tested for variants of stx(1), stx(2), and eae. Approximately 80% (138 of 174) were positive for stx(1) and/or stx(2), with stx(1) as the most prevalent (66%). Of the stx(1) variants, stx(1) was the most common (76%) followed by stx(1c) (22%). Analysis of stx(2)-positive isolates found 20 (53%) stx(2), 13 (34%) stx(2)/stx(2v-ha), 3 (8%) stx(2v-ha), 1 (3%) stx(2v-hb), and 1 (3%) stx(2d-activatable). Findings of stx(2)/stx(2v-ha) and stx(2d-activatable) are noteworthy given associations with hemolytic uremic syndrome and increased cytotoxicity, respectively. Of the Stx positive, 94 (68%) were eae positive with 31 (33%) eae(varepsilon1), 19 (20%) eae(gamma1), and 18 (19%) eae(beta1). A predominance of eae(varepsilon1) may suggest a new pathogenic significance because, reportedly, eae(beta1) is one of the most widespread variants.

  11. The Prognosis of Acute Low Back Pain in Primary Care in the U.S. A 2-Year Prospective Cohort Study

    PubMed Central

    Mehling, Wolf E.; Gopisetty, Viranjini; Bartmess-LeVasseur, Elizabeth; Acree, Mike; Pressman, Alice; Goldberg, Harley; Hecht, Frederick M; Carey, Tim; Avins, Andrew L

    2011-01-01

    Study Design Prospective cohort study Objective to assess the prognosis of patients presenting with acute low back pain (LBP) in a primary care setting in the U.S. Summary of Background Data Practice guidelines for acute LBP based on return-to-work outcomes underestimate the development of chronic pain in the primary care setting. Due to differences in inclusion criteria, chronic pain definitions and national health systems, prognostic cohort studies have reported a wide range of results limiting interpretation and generalization. Current data from carefully designed prognostic studies of acute LBP are lacking for the U.S. primary care system. Methods Members of a large health service organization were enrolled after seeking medical care for acute LBP, with or without sciatica, of up to 30 days duration, with no prior episode in the past 12 months and no history of spine surgery. We conducted phone interviews at baseline, six months and two years. Based on receiver operating characteristic analyses, a combination of global perceived recovery with pain intensity was used as primary outcome for chronic pain. Recurrence and multiple secondary outcomes were assessed to allow for comparison with other studies. Results 605 patients had an average pain intensity of 5.6 (numeric rating scale 0–10) and disability of 15.8 (Roland Morris scale 0–24). Eight percent had declared sick leave between pain onset and baseline interview. 13% of 521 patients (86% follow-up) suffered from chronic pain at six months and 19% of 443 patients at 2 years. At six months, 54% had experienced at least one LBP recurrence, and 47% in the subsequent 18 months. Conclusion The prognosis of strictly-defined acute LBP, with or without sciatica, is less favorable than commonly stated in practice guidelines based on failure to return to work. Broad initiatives to develop new means for the primary and secondary prevention of recurrent and chronic LBP are urgently needed. PMID:22504516

  12. Exploring the Relationship between Autistic-Like Traits and ADHD Behaviors in Early Childhood: Findings from a Community Twin Study of 2-Year-Olds

    ERIC Educational Resources Information Center

    Ronald, Angelica; Edelson, Lisa R.; Asherson, Philip; Saudino, Kimberly J.

    2010-01-01

    Behaviors characteristic of autism and ADHD emerge in early childhood, yet research investigating their comorbidity has focused on older children. This study aimed to explore the nature of the relationship between autistic-like traits and ADHD behaviors in a community sample of 2-year-olds. Twins from the Boston University Twin Project (N = 312…

  13. The Role of Pictures and Gestures as a Support Mechanism for Novel Word Learning: A Training Study with 2-Year-Old Children

    ERIC Educational Resources Information Center

    Kapalková, Svetlana; Polišenská, Kamila; Süssová, Martina

    2016-01-01

    A training study examined novel word learning in 2-year-old children and assessed two nonverbal mechanisms, pictures and gestures, which are commonly used as communication support. The aim was to (1) compare these two support mechanisms and measure their effects on expressive word learning and (2) to investigate these effects on word production…

  14. Do Deviant Peer Associations Mediate the Contributions of Self-Esteem to Problem Behavior During Early Adolescence? A 2-Year Longitudinal Study

    ERIC Educational Resources Information Center

    DuBois, David L.; Silverthorn, Naida

    2004-01-01

    We investigated deviant peer associations as a mediator of the influences of general and peer-oriented self-esteem on problem behavior using data from a 2-year longitudinal study of 350 young adolescents. Measures of problem behavior included substance use (alcohol use, smoking) and antisocial behavior (fighting, stealing). Using latent growth…

  15. A retrospective study of radiographic abnormalities in the repositories of 2-year-old Thoroughbred in-training sales in Japan

    PubMed Central

    MIYAKOSHI, Daisuke; SENBA, Hiroyuki; SHIKICHI, Mitsumori; MAEDA, Masaya; SHIBATA, Ryo; MISUMI, Kazuhiro

    2016-01-01

    ABSTRACT This study aimed to evaluate the influence of radiographic abnormalities of 2-year-old Thoroughbred horses that were listed at in-training sales in Japan, on whether they started to race or not at 2–3 years of age. Radiographs of 850 2-year-old Thoroughbreds in the in-training sales repository from 2007 to 2010 were reviewed, and 26 categories of radiographic abnormalities were found. Forty-three horses (5.1%, 43/850) did not start a race at 2–3 years of age. In accordance with the racing results for this age category, as determined by Fisher’s exact test and multiple logistic regression analysis, none of the radiographic abnormalities were significantly related to failure to start a race. At 2 years of age, 198 horses (23.3%, 198/850) did not start a race. Horses with enlargement of the proximal sesamoid bones in the fore (9 of 19 horses) and hind limbs (5 of 9 horses) did not start a race at the age of 2 years, and fewer of these horses (fore, P=0.021; hind, P=0.030) started a race at the age of 2 years compared with the population of horses without these radiographic abnormalities. These results suggest that identification of radiographic enlargement of the proximal sesamoid bones during training sales could derail the racing debut of horses at the age of 2 years. However, this might not necessarily indicate a poor prognosis and resulting in retirement from racing at 2–3 years of age. PMID:27330400

  16. GUIDE FOR CONDUCTING TREATABILITY STUDIES UNDER CERCLA

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the removal process, remedial investigation/ feasibility study (RI/FS) process and the remedial design/remedial action (RD/RA) process under the Comprehensive Environmental Response...

  17. Increased Regulatory T-Cell Percentage Contributes to Poor CD4(+) Lymphocytes Recovery: A 2-Year Prospective Study After Introduction of Antiretroviral Therapy.

    PubMed

    Saison, Julien; Maucort Boulch, Delphine; Chidiac, Christian; Demaret, Julie; Malcus, Christophe; Cotte, Laurent; Poitevin-Later, Francoise; Miailhes, Patrick; Venet, Fabienne; Trabaud, Mary Anne; Monneret, Guillaume; Ferry, Tristan

    2015-04-01

    Background.  The primary aim of this study was to determine the impact of regulatory T cells (Tregs) percentage on immune recovery in human immunodeficiency virus (HIV)-infected patients after antiretroviral therapy introduction. Methods.  A 2-year prospective study was conducted in HIV-1 chronically infected naive patients with CD4 count <500 cells/mm(3). Regulatory T cells were identified as CD4(+)CD25(high)CD127(low) cells among CD4(+) lymphocytes. Effect of Treg percentage at inclusion on CD4 evolution overtime was analyzed using a mixed-effect Poisson regression for count data. Results.  Fifty-eight patients were included (median CD4 = 293/mm(3), median Treg percentage = 6.1%). Percentage of Treg at baseline and CD4 nadir were independently related to the evolution of CD4 absolute value according to time: (1) at any given nadir CD4 count, 1% increase of initial Treg was associated with a 1.9% lower CD4 absolute value at month 24; (2) at any given Treg percentage at baseline, 10 cell/mm(3) increase of CD4 nadir was associated with a 2.4% increase of CD4 at month 24; and (3) both effects did not attenuate with time. The effect of Treg at baseline on CD4 evolution was as low as the CD4 nadir was high. Conclusions.  Regulatory T-cell percentage at baseline is a strong independent prognostic factor of immune recovery, particularly among patients with low CD4 nadir.

  18. Trait and State Attributes of Insight in First Episodes of Early-Onset Schizophrenia and Other Psychoses: A 2-Year Longitudinal Study

    PubMed Central

    Parellada, Mara; Boada, Leticia; Fraguas, David; Reig, Santiago; Castro-Fornieles, Josefina; Moreno, Dolores; Gonzalez-Pinto, Ana; Otero, Soraya; Rapado-Castro, Marta; Graell, Montserrat; Baeza, Inmaculada; Arango, Celso

    2011-01-01

    Background: Increasing evidence supports the important role of illness state and individual characteristics in insight. Methods: Insight, as measured with the Scale to Assess Unawareness of Mental Disorder, over the first 2 years of early-onset first-episode psychosis and its correlations with clinical, socio-demographic, cognitive, and structural brain variables are studied. Results: (1) insight at 2 years is poorer in schizophrenia spectrum disorders (SSDs) than in subjects with other psychoses; (2) the more severe the psychosis, the worse the insight. In SSD, depressive symptoms, poorer baseline executive functioning, lower IQ, longer duration of untreated psychosis (DUP), and poorer premorbid infancy adjustment are associated with poorer insight; frontal and parietal gray matter (GM) reductions at baseline correlate with worse insight into having psychotic symptoms at 2 years; (3) insight into having a mental disorder (Scale to Assess Unawareness of Mental Disorder [SUMD]1) at 1 year, DUP, and baseline IQ are the most consistent variables explaining different aspects of insight at 2 years in SSD patients. IQ and SUMD1 at 1 year, together with left frontal and parietal GM volumes, explain 80% of the variance of insight into having specific psychotic symptoms in SSD patients (adjusted R2 = 0.795, F = 15.576, P < .001). Conclusion: Insight is a complex phenomenon that depends both on severity of psychopathology and also on disease and subject characteristics, such as past adjustment, IQ, DUP, cognitive functioning, frontal and parietal GM volumes, and age, gender, and ethnicity. PMID:20884756

  19. Diurnal Cortisol Secretion at Home and in Child Care: A Prospective Study of 2-Year-Old Toddlers

    ERIC Educational Resources Information Center

    Ouellet-Morin, Isabelle; Tremblay, Richard E.; Boivin, Michel; Meaney, Michael; Kramer, Michael; Cote, Sylvana M.

    2010-01-01

    Background: Previous studies indicate that children may experience disrupted cortisol secretion in child care. The extent to which this is a transient or long-term disruption is not known, as most studies have relied on cross-sectional designs, and age-heterogeneous small sample sizes. This study aims to (a) compare cortisol secretion measured at…

  20. Guide for Conducting Energy Efficiency Potential Studies

    EPA Pesticide Factsheets

    The Guide for Conducting Energy Efficiency Potential Studies is provided to assist state officials, regulators, legislators, and others in implementing the recommendations of the National Action Plan for Energy Efficiency.

  1. The Role of Behavioral Self-Regulation in Learning to Read: A 2-Year Longitudinal Study of Icelandic Preschool Children

    ERIC Educational Resources Information Center

    Birgisdóttir, Freyja; Gestsdóttir, Steinunn; Thorsdóttir, Fanney

    2015-01-01

    Research Findings: Research suggests that behavioral self-regulation skills are critical for early school success, including success in literacy, but few studies have explored the relations that behavioral self-regulation may have with different components of early literacy development. The present study investigated the longitudinal contribution…

  2. DC electrical conductivity study of cerium doped conducting glass systems

    NASA Astrophysics Data System (ADS)

    Barde, R. V.; Waghuley, S. A.

    2013-06-01

    The glass samples of composition 60V2O5-5P2O5-(35-x)B2O3-xCeO2, (1 ≤ x ≤ 5) were prepared by the conventional melt quench method. The samples were characterized by X-ray diffraction and thermo gravimetric-differential thermal analysis. The glass transition temperature and crystallization temperature determined from TG-DTA analysis. The DC electrical conductivity has been carried out in the temperature range 303-473 K. The maximum conductivity and minimum activation energy were found to be 0.039 Scm-1 and 0.15 eV at 473 K for x=1, respectively.

  3. 2-Year Natural Decline of Cardiac Sympathetic Innervation in Idiopathic Parkinson Disease Studied with 11C-Hydroxyephedrine PET.

    PubMed

    Wong, Ka Kit; Raffel, David M; Bohnen, Nicolaas I; Altinok, Gulcin; Gilman, Sid; Frey, Kirk A

    2017-02-01

    The objective of this study was to detect regional patterns of cardiac sympathetic denervation in idiopathic Parkinson disease (IPD) using (11)C-hydroxyephedrine ((11)C-HED) PET and determine the denervation rate over 2 y.

  4. Alcoholics anonymous involvement and positive alcohol-related outcomes: cause, consequence, or just a correlate? A prospective 2-year study of 2,319 alcohol-dependent men.

    PubMed

    McKellar, John; Stewart, Eric; Humphreys, Keith

    2003-04-01

    A positive corelation between Alcoholics Anonymous (AA) involvement and better alcohol-related outcomes has been identified in research studies, but whether this correlation reflects a causal relationship remains a subject of meaningful debate. The present study evaluated the question of whether AA affiliation appears causally related to positive alcohol-related outcomes in a sample of 2,319 male alcohol-dependent patients. An initial structural equation model indicated that 1-year posttreatment levels of AA affiliation predicted lower alcohol-related problems at 2-year follow-up, whereas level of alcohol-related problems at 1-year did not predict AA affiliation at 2-year follow-up. Additional models found that these effects were not attributable to motivation or psychopathology. The findings are consistent with the hypothesis that AA participation has a positive effect on alcohol-related outcomes.

  5. Self-Regulation in Children Born with Extremely Low Birth Weight at 2 Years Old: A Comparison Study

    ERIC Educational Resources Information Center

    Lynn, Lisa N.; Cuskelly, Monica; Gray, Peter H.; O'Callaghan, Michael J.

    2012-01-01

    Survival rates for children born with extremely low birth weight (ELBW) are increasing; however, many of these children experience later problems with learning. This study adopted an integrated approach to these problems, involving the self-regulatory tasks of inhibition and delay of gratification and relevant individual factors including…

  6. Instructional Faculty and Staff in Public 2-year Colleges. Statistical Analysis Report. 1993 National Study of Postsecondary Faculty (NSOPF:93).

    ERIC Educational Resources Information Center

    Palmer, James C.

    Drawing on data from the 1993 National Study of Postsecondary Faculty, this analysis sought to differentiate instructional faculty and staff at public two-year colleges by age (under 35 vs. 55-64) and by years of experience in the current job (under 10 years vs. 20 or more years). The report examines differences by primary teaching field,…

  7. The Predictive Relationship between Temperament, School Adjustment, and Academic Achievement: A 2-Year Longitudinal Study of Children At-Risk

    ERIC Educational Resources Information Center

    Al-Hendawi, Maha

    2010-01-01

    Individual differences in temperament can be a risk or a protective factor for a child, especially for children at-risk who possess single or multiple risk factors that may interfere with their educational success and affect their healthy development and their life-long outcomes. This research study examined the concurrent and longitudinal…

  8. Educational system for transplant coordinators in Poland: postgraduate studies at Warsaw Medical University; 2 years of experience.

    PubMed

    Czerwiński, J; Jakubowska-Winecka, A; Becler, R; Kubik, T; Milecka, A; Sekta, S; Pabisiak, K; Malanowski, P; Rowinński, W

    2009-10-01

    Donor hospital transplant coordinators play crucial roles in the donation process. There are only a few coordinators in Poland, while there are about 400 hospitals with intensive care units (ICU). Coordinators must be professionals in medical sciences, clinical psychology, law, organization, management, and statistics. Coordinators acquire these skills during the Transplant Coordinators Postgraduate Studies at Warsaw Medical University which began in 2007. Lectures, seminars and exercises (99 hours, 6 weekends) are run by experts. The studies end with an examination and a diploma. The main criterion for acceptance of a candidate is employment in a key department in the donation process. The aim of studies is to educate coordinators for each hospital in the country. Until now 4 editions of the course have been completed. Among 123 graduates, 71 (60%) are employed in strategic departments of 48 hospitals. Preliminary results of graduates' activities in donor detection were compared in the periods before (2005-2006) and after the course (2007-2008). The background was the overall activity in Poland, where in 2007-2008 the activity fell to 79% of 2005-2006. This fall for hospitals with the graduates of this program was 82% versus hospitals without them (76%). Of the 48 hospitals that employed the graduates: 14 improved donation 5 were the same, in 12 in both periods showed no donations; whereas in 11 it was much lower (>20%), and in 6 lower but consistent with the national trend.

  9. Historical control data of neoplastic lesions in the Wistar Hannover Rat among eight 2-year carcinogenicity studies.

    PubMed

    Carlus, Marine; Elies, Laëtitia; Fouque, Marie-Claude; Maliver, Pierre; Schorsch, Frédéric

    2013-03-01

    Incidences of neoplastic lesions were evaluated in untreated Hannover Wistar Rats RjHan: WI (470 males and 470 females) used as control animals in eight carcinogenicity studies. All these studies were performed in a similar environment either for the in vivo and the postmortem evaluation. The major neoplastic lesions were found in the endocrine, integumentary and reproductive systems. Pituitary adenoma was the most frequent neoplasm and occurred in 33.9% of the males and 54.6% of the female rats. The other most frequent tumors in males were thyroid C-cell adenoma (8.6%), pancreatic islet cell adenoma (8.1%), subcutaneous fibrosarcoma (6.6%), subcutaneous fibroma (4.7%), benign pheochromocytoma (3.4%), and cutaneous keratoacanthoma (3.4%). In females, the other highest incidences were mammary fibroadenoma (29%), uterine endometrial stromal polyp (18.1%), mammary adenocarcinoma (14.2%), mammary fibroadenoma with atypia (13.7%), thyroid C-cell adenoma (7.5%), benign thymoma (3.7%), and subcutaneous fibrosarcoma (3.6%). All these data were compared to previously published historical control data. This retrospective analysis was undergone in order to illustrate the result of a stable organization which guarantees a robust historical data base for neoplastic and non neoplastic findings.

  10. Cardiovascular effects of dietary salt intake in aged healthy cats: a 2-year prospective randomized, blinded, and controlled study.

    PubMed

    Chetboul, Valérie; Reynolds, Brice Stéphane; Trehiou-Sechi, Emilie; Nguyen, Patrick; Concordet, Didier; Sampedrano, Carolina Carlos; Testault, Isabelle; Elliott, Jonathan; Abadie, Jérôme; Biourge, Vincent; Lefebvre, Hervé Pierre

    2014-01-01

    High salt dry expanded diets are commercially available for cats to increase water intake and urine volume, as part of the prevention or treatment of naturally occurring urinary stone formation (calcium oxalates and struvites). However, chronic high salt intake may have potential cardiovascular adverse effects in both humans, especially in aging individuals, and several animal models. The objective of this prospective, randomized, blinded, and controlled study was to assess the long-term cardiovascular effects of high salt intake in healthy aged cats. Twenty healthy neutered cats (10.1 ± 2.4 years) were randomly allocated into 2 matched groups. One group was fed a high salt diet (3.1 g/Mcal sodium, 5.5 g/Mcal chloride) and the other group a control diet of same composition except for salt content (1.0 g/Mcal sodium, 2.2 g/Mcal chloride). Clinical examination, systolic and diastolic arterial blood pressure measurements, standard transthoracic echocardiography and conventional Doppler examinations were repeatedly performed on non-sedated cats by trained observers before and over 24 months after diet implementation. Radial and longitudinal velocities of the left ventricular free wall and the interventricular septum were also assessed in systole and diastole using 2-dimensional color tissue Doppler imaging. Statistics were performed using a general linear model. No significant effect of dietary salt intake was observed on systolic and diastolic arterial blood pressure values. Out of the 33 tested imaging variables, the only one affected by dietary salt intake was the radial early on late diastolic velocity ratio assessed in the endocardium of the left ventricular free wall, statistically lower in the high salt diet group at 12 months only (P = 0.044). In conclusion, in this study involving healthy aged cats, chronic high dietary salt intake was not associated with an increased risk of systemic arterial hypertension and myocardial dysfunction, as observed in some

  11. Degrees of Antioxidant Protection: A 2-Year Study of the Bioactive Properties of Organic Milk in Poland.

    PubMed

    Puppel, Kamila; Sakowski, Tomasz; Kuczyńska, Beata; Grodkowski, Grzegorz; Gołębiewski, Marcin; Barszczewski, Jerzy; Wróbel, Barbara; Budziński, Arkadiusz; Kapusta, Aleksandra; Balcerak, Marek

    2017-02-01

    The aim of this study was to determine the nutritional value of organic milk in Poland, investigate the influence of diet on antioxidant capacity and degree of antioxidant protection (DAP), and to examine the effect of season on the bioactive properties of milk from organic farms. From 2014 to 2015, 820 milk samples were collected from 6 organic farms during indoor feeding season (IDS) and pasture feeding season (PS). Pasture feeding season + corn grain (PSCG) cows' daily ration during pasture feeding season was enriched with 4 kg a day of corn to improve dietary energy balance. Milk obtained during PS was found to have a higher fat content, slight but significantly lower protein content compared with milk from IDS. The study showed that the content of monounsaturated fatty acids (MUFA) in milk fat was strongly linked to the concentration of polyunsaturated fatty acids (PUFA) and, to a lesser extent, on the supply of MUFA. The IDS data (concentration of vitamin E, A, and β-carotene) showed the lowest values compared with the PS and PSCG groups. Total antioxidant status (TAS) and DAP showed an increasing trend in organic milk. PSCG was associated with highest level of DAP (9% higher than PS and 79% higher than IDS) and TAS (37% higher than PS and 79% higher than IDS). The results obtained show that supplementation of the basic ration with corn grain improved both TAS and DAP. The higher DAP and TAS value is responsible for product stability, considering the risk factor related to levels of cholesterol-oxide intake in humans.

  12. Proton Conductivity Studies on Biopolymer Electrolytes

    SciTech Connect

    Harun, N. I.; Sabri, N. S.; Rosli, N. H. A.; Taib, M. F. M.; Saaid, S. I. Y.; Kudin, T. I. T.; Ali, A. M. M.; Yahya, M. Z. A.

    2010-07-07

    Proton conducting solid biopolymer electrolyte membranes consisting of methyl cellulose (MC) and different wt.% of ammonium nitrate (NH{sub 4}NO{sub 3}) were prepared by solution cast technique. Impedance spectroscopy was carried out to study electrical characteristics of bulk materials. The ionic conductivity of the prepared samples was calculated using the bulk resistance (R{sub b}) obtained from impedance spectroscopy plot. The highest ionic conductivity obtained was 1.17x10{sup -4} Scm{sup -1} for the sample with composition ratio of MC(50): NH{sub 4}NO{sub 3}(50). To enhance the ionic conductivity, propylene carbonate (PC) and ethylene carbonate (EC) plasticizers were introduced. It was found that the ionic conductivity of polymer electrolyte membranes increased with the increase in plasticizers concentration. The ionic conductivities of solid polymer electrolytes based on MC-NH{sub 4}NO{sub 3}-PC was enhanced up to 4.91x10{sup -3} Scm{sup -1} while for the MC-NH{sub 4}NO{sub 3}-EC system, the highest conductivity was 1.74x10{sup -2} Scm{sup -1}. The addition of more plasticizer however decreases in mechanical stability of the membranes.

  13. Use of iron supplements in children aged 1-2 years with iron deficiency anemia: A cross-sectional study

    PubMed Central

    Sezik, Handan Atsiz; Can, Huseyin; Kurnaz, Mehmet Ali; Tuna, Mine; Ay, Zeynep

    2015-01-01

    Objectives: Iron deficiency (ID) is the most common nutritional problem in the world and is the most common cause of childhood anemia. In this study, our aim was to find out about the state of usage of iron preparation, which is distributed free of charge by the Ministry of Health, for the infants between 4-12 months in our country, as well as detecting the awareness degree of families those who are informed about iron-deficiency anemia (IDA), prophylaxis of the drug and to determine the drug’s effectiveness. Methods: It was a cross-sectional survey. The laboratory values from the files of the children aged 1-2 those who visited our hospital’s department of pediatrics, between January 2010 to August 2013, were collected. The survey included families who have children diagnosed with IDA. Questions included about families’ sociodemographic characteristics, the state of the usage of the iron drug, how much information received in terms of the side effects- consumption period and dosage. Results: A total of 139 children were enrolled in our study. While 77.7% of the families who participated stated that (n = 108) iron medicine was prescribed other 43.2% of families stated (n = 60) was prescribed and they were informed about iron pills and IDA. 25.9% of families had received information about drug’s side effects, 74.8% of them had information about period of consumption and 77.7% said they were given information about the drug dose. The average duration of use of iron medicine was 6.98±4.52 (min: 1, max: 24) months. It has been noted that; parent’s education level, mother’s occupation, child’s gender, how the child was born and receiving information about how to use the medicine had no effects on usage of the drug in children. Nevertheless, it has been noticed that, when the families were given proper information the drug use increased and the patients compliance with medications also increased. Conclusion: We believe that, due to frequent diagnosis of

  14. Cardiovascular Effects of Dietary Salt Intake in Aged Healthy Cats: A 2-Year Prospective Randomized, Blinded, and Controlled Study

    PubMed Central

    Chetboul, Valérie; Reynolds, Brice Stéphane; Trehiou-Sechi, Emilie; Nguyen, Patrick; Concordet, Didier; Sampedrano, Carolina Carlos; Testault, Isabelle; Elliott, Jonathan; Abadie, Jérôme; Biourge, Vincent; Lefebvre, Hervé Pierre

    2014-01-01

    High salt dry expanded diets are commercially available for cats to increase water intake and urine volume, as part of the prevention or treatment of naturally occurring urinary stone formation (calcium oxalates and struvites). However, chronic high salt intake may have potential cardiovascular adverse effects in both humans, especially in aging individuals, and several animal models. The objective of this prospective, randomized, blinded, and controlled study was to assess the long-term cardiovascular effects of high salt intake in healthy aged cats. Twenty healthy neutered cats (10.1±2.4 years) were randomly allocated into 2 matched groups. One group was fed a high salt diet (3.1 g/Mcal sodium, 5.5 g/Mcal chloride) and the other group a control diet of same composition except for salt content (1.0 g/Mcal sodium, 2.2 g/Mcal chloride). Clinical examination, systolic and diastolic arterial blood pressure measurements, standard transthoracic echocardiography and conventional Doppler examinations were repeatedly performed on non-sedated cats by trained observers before and over 24 months after diet implementation. Radial and longitudinal velocities of the left ventricular free wall and the interventricular septum were also assessed in systole and diastole using 2-dimensional color tissue Doppler imaging. Statistics were performed using a general linear model. No significant effect of dietary salt intake was observed on systolic and diastolic arterial blood pressure values. Out of the 33 tested imaging variables, the only one affected by dietary salt intake was the radial early on late diastolic velocity ratio assessed in the endocardium of the left ventricular free wall, statistically lower in the high salt diet group at 12 months only (P = 0.044). In conclusion, in this study involving healthy aged cats, chronic high dietary salt intake was not associated with an increased risk of systemic arterial hypertension and myocardial dysfunction, as observed in some

  15. 2-year study of chemical composition of bulk deposition in a South China coastal city: comparison with East Asian cities

    SciTech Connect

    K.M. Wai; P.A. Tanner; C.W.F. Tam

    2005-09-01

    Using the emission strengths of the precursor gases, the nature of soil in China, the ventilation power and half value rainout region length, the nss-SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Ca{sup 2+}, and NH{sub 4}{sup +} concentrations, and pH of rainwater at Hong Kong and other cities of China and Japan are compared and rationalized. The chemical composition of Hong Kong bulk deposition from 1998 to 2000 is taken from the collection and analysis of 156 daily samples. The volume-weighted average (VWA) pH is 4.2 over the whole study period. Nonsea salt- (nss-) sulfate is the most abundant species in the samples, and the pH mostly depended upon the concentrations of the major species nss-SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Ca{sup 2+}, and NH{sub 4}{sup +}. All species concentrations show higher levels in the cold season (especially NO{sub 3}- and Ca{sup 2+}), which indicates the dominant dilution effects in the warm season due to heavy rainfall and the influence of the continental outflow of pollutants during the cold season. For Hong Kong bulk deposition, the VWA pH is slightly lower in the cold season, and there is a slight decrease in VWA pH over the period from 1994 to 2000. The impact of acid rain in Hong Kong is briefly discussed. 36 refs., 3 figs., 5 tabs.

  16. A longitudinal study of Giardia duodenalis genotypes in dairy cows from birth to 2 years of age.

    PubMed

    Santín, Mónica; Trout, James M; Fayer, Ronald

    2009-05-26

    Fecal specimens were collected from 30 calves from birth to 24 months of age at a dairy farm in Maryland to determine the prevalence of Giardia duodenalis genotypes in cattle of different ages. Fecal samples were subjected to density gradient centrifugation to remove debris and concentrate cysts. Specimens were analyzed by immunofluorescence microscopy and polymerase chain reaction (PCR). All PCR positive specimens were sequenced using the SSU-rRNA gene of Giardia. All 30 calves shed G. duodenalis cysts at some time during the study. Of 990 specimens, 312 were positive for G. duodenalis (31.5%). The highest prevalence of infection occurred at weeks 4 and 5 of age with 25 out of 30 calves shedding cysts at those sampling times. Overall, pre-weaned calves (<8 weeks of age) exhibited the highest prevalence (60.8%), followed by post-weaned calves (3-12 months of age) (32.1%) and heifers (12-24 months of age) (11.4%). Sequence analysis of the 312 PCR-positive samples revealed the presence of both Assemblages A and E, G. duodenalis, with cumulative prevalences of 70% and 100%, respectively. Assemblage A was not detected in pre-weaned calves, but was detected in 6.9% and 4.7% of post-weaned calves and heifers, respectively. These data indicate not only that calves are infected with both Assemblages A and E simultaneously, but also that infections with zoonotic Assemblage A, G. duodenalis are more common than previously reported. Thus, calves appear to be a more significant reservoir of human infectious G. duodenalis than previous data have suggested.

  17. Cementless anatomical prosthesis for the treatment of 3-part and 4-part proximal humerus fractures: cadaver study and prospective clinical study with minimum 2 years followup

    PubMed Central

    Obert, Laurent; Saadnia, Rachid; Loisel, François; Uhring, Julien; Adam, Antoine; Rochet, Séverin; Clappaz, Pascal; Lascar, Tristan

    2016-01-01

    Introduction: The purpose of this study was to evaluate the functional and radiological outcomes of a cementless, trauma-specific locked stem for 3- and 4-part proximal humeral fractures. Materials and methods: This study consisted of two parts: a cadaver study with 22 shoulders and a multicenter prospective clinical study of 23 fracture patients evaluated at least 2 years after treatment. In the cadaver study, the locked stem (HumelockTM, FX Solutions) and its instrumentation were evaluated. In the clinical study, five senior surgeons at four different hospitals performed the surgical procedures. An independent surgeon evaluated the patients using clinical (Constant score, QuickDASH) and radiological (X-rays, CT scans) outcome measures. Results: The cadaver study allowed us to validate the height landmarks relative to the pectoralis major tendon. In the clinical study, at the review, abduction was 95° (60–160), forward flexion was 108° (70–160), external rotation (elbow at body) was 34° (0–55), the QuickDASH was 31 (4.5–59), the overall Constant score was 54 (27–75), and the weighted Constant score was 76 (31.5–109). Discussion: This preliminary study of hemiarthroplasty (HA) with a locked stem found results that were at least equivalent to published series. As all patients had at least a 2-year follow-up, integration of the locked stem did not cause any specific complications. These results suggest that it is possible to avoid using cement when hemiarthroplasty is performed for the humeral stem. This implant makes height adjustment and transosseous suturing of the tuberosities more reproducible. PMID:27194107

  18. Joint unloading implant modifies subchondral bone trabecular structure in medial knee osteoarthritis: 2-year outcomes of a pilot study using fractal signature analysis

    PubMed Central

    Miller, Larry E; Sode, Miki; Fuerst, Thomas; Block, Jon E

    2015-01-01

    Background Knee osteoarthritis (OA) is largely attributable to chronic excessive and aberrant joint loading. The purpose of this pilot study was to quantify radiographic changes in subchondral bone after treatment with a minimally invasive joint unloading implant (KineSpring® Knee Implant System). Methods Nine patients with unilateral medial knee OA resistant to nonsurgical therapy were treated with the KineSpring System and followed for 2 years. Main outcomes included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, and stiffness subscores and independent core laboratory determinations of joint space width and fractal signature of the tibial cortex. Results WOMAC scores, on average, improved by 92% for pain, 91% for function, and 79% for stiffness over the 2-year follow-up period. Joint space width in the medial compartment of the treated knee significantly increased from 0.9 mm at baseline to 3.1 mm at 2 years; joint space width in the medial compartment of the untreated knee was unchanged. Fractal signatures of the vertically oriented trabeculae in the medial compartment decreased by 2.8% in the treated knee and increased by 2.1% in the untreated knee over 2 years. No statistically significant fractal signature changes were observed in the horizontally oriented trabeculae in the medial compartment or in the horizontal or vertical trabeculae of the lateral compartment in the treated knee. Conclusion Preliminary evidence suggests that the KineSpring System may modify knee OA disease progression by increasing joint space width and improving subchondral bone trabecular integrity, thereby reducing pain and improving joint function. PMID:25670891

  19. Ethical issues in conducting migrant farmworker studies.

    PubMed

    Cooper, Sharon P; Heitman, Elizabeth; Fox, Erin E; Quill, Beth; Knudson, Paula; Zahm, Sheila H; MacNaughton, Nancy; Ryder, Roberta

    2004-01-01

    Migrant farmworkers should be considered a vulnerable population because they work in a hazardous industry, are often members of an ethnic minority, have known difficulty in accessing health care, and are often of lower socioeconomic status. For these reasons, too, it is extremely important to conduct health-related research with this often-underserved group. However, because migrant farmworkers are vulnerable, investigators must be especially vigilant in protecting them from the potential harms of research and in ensuring that the special ethical issues that arise in research with this population are identified and addressed for every project. In response to the National Cancer Institute's concerns about the feasibility of conducting epidemiologic studies among migrant farmworkers, researchers undertook four feasibility studies near the Texas-Mexico border. Each study raised different, complex ethical questions that challenged the investigators, but whose resolution turned out to be crucial to the success of the studies.

  20. A randomized study on migration of the Spectron EF and the Charnley flanged 40 cemented femoral components using radiostereometric analysis at 2 years

    PubMed Central

    2011-01-01

    Background and purpose We performed a randomized study to determine the migration patterns of the Spectron EF femoral stem and to compare them with those of the Charnley stem, which is regarded by many as the gold standard for comparison of implants due to its extensive documentation. Patients and methods 150 patients with a mean age of 70 years were randomized, single-blinded, to receive either a cemented Charnley flanged 40 monoblock, stainless steel, vaquasheen surface femoral stem with a 22.2-mm head (n = 30) or a cemented Spectron EF modular, matte, straight, collared, cobalt-chrome femoral stem with a 28-mm femoral head and a roughened proximal third of the stem (n = 120). The patients were followed with repeated radiostereometric analysis for 2 years to assess migration. Results At 2 years, stem retroversion was 2.3° and 0.7° (p < 0.001) and posterior translation was 0.44 mm and 0.17 mm (p = 0.002) for the Charnley group (n = 26) and the Spectron EF group (n = 74), respectively. Subsidence was 0.26 mm for the Charnley and 0.20 mm for the Spectron EF (p = 0.5). Interpretation The Spectron EF femoral stem was more stable than the Charnley flanged 40 stem in our study when evaluated at 2 years. In a report from the Norwegian arthroplasty register, the Spectron EF stem had a higher revision rate due to aseptic loosening beyond 5 years than the Charnley. Initial stability is not invariably related to good long-term results. Our results emphasize the importance of prospective long-term follow-up of prosthetic implants in clinical trials and national registries and a stepwise introduction of implants. PMID:21895504

  1. Respiratory symptoms and ventilatory function among health-care workers exposed to cleaning and disinfectant chemicals, a 2-year follow-up study.

    PubMed

    El-Helaly, Mohamed; Balkhy, Hanan H; Waseem, Khan; Khawaja, Sahdia

    2016-12-01

    Previous cross-sectional studies have shown that exposure to cleaning chemicals among health-care workers (HCWs) is associated with respiratory disorders and ventilatory function changes. This study aimed to further explore this association using a longitudinal approach. A prospective 2-year follow-up study was carried out at a tertiary care hospital in Saudi Arabia from June 2012 to June 2014 among 56 nurses who were responsible for disinfection and sterilization of medical instruments and equipment. The workplaces of the participants were assessed for engineering, environmental, and safety control measures. Self-administered questionnaires were distributed to all participants to assess their exposure to cleaning chemicals and their medical history. Spirometric parameters were measured for all nurses in 2012 (baseline) and again in 2014 (follow-up). The prevalence of work-related respiratory symptoms did not increase significantly over this time. Among all the spirometric parameters, only forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio decreased significantly, and only 10.7% of participants who were exposed to cleaning chemicals for more than 10 years had FEV1 and FVC less than their longitudinal normal limits at the end of the study. Smoking and gender were associated with statistically significant decreases in some of the spirometric parameters. Our 2-year follow-up study did not demonstrate significant association between exposure to cleaning chemicals among HCWs and changes in the prevalence of work-related respiratory symptoms, but indicated early effects on ventilatory function among them. The study highlights the importance of periodic spirometry, proper work practices, and effective control measures to protect HCWs against potentially harmful workplace chemicals for disinfection and sterilization.

  2. Amplitude of Low-frequency Oscillations in Parkinson's Disease: A 2-year Longitudinal Resting-state Functional Magnetic Resonance Imaging Study

    PubMed Central

    Hu, Xiao-Fei; Zhang, Jiu-Quan; Jiang, Xiao-Mei; Zhou, Chao-Yang; Wei, Lu-Qing; Yin, Xun-Tao; Li, Jing; Zhang, Yan-Ling; Wang, Jian

    2015-01-01

    Background: Neuroimaging studies have found that functional changes exist in patients with Parkinson's disease (PD). However, the majority of functional magnetic resonance imaging (fMRI) studies in patients with PD are task-related and cross-sectional. This study investigated the functional changes observed in patients with PD, at both baseline and after 2 years, using resting-state fMRI. It further investigated the relationship between whole-brain spontaneous neural activity of patients with PD and their clinical characteristics. Methods: Seventeen patients with PD underwent an MRI procedure at both baseline and after 2 years using resting-state fMRI that was derived from the same 3T MRI. In addition, 20 age- and sex-matched, healthy controls were examined using resting-state fMRI. The fractional amplitude of low-frequency fluctuation (fALFF) approach was used to analyze the fMRI data. Nonlinear registration was used to model within-subject changes over the scanning interval, as well as changes between the patients with PD and the healthy controls. A correlative analysis between the fALFF values and clinical characteristics was performed in the regions showing fALFF differences. Results: Compared to the control subjects, the patients with PD showed increased fALFF values in the left inferior temporal gyrus, right inferior parietal lobule (IPL) and right middle frontal gyrus. Compared to the baseline in the 2 years follow-up, the patients with PD presented with increased fALFF values in the right middle temporal gyrus and right middle occipital gyrus while also having decreased fALFF values in the right cerebellum, right thalamus, right striatum, left superior parietal lobule, left IPL, left precentral gyrus, and left postcentral gyrus (P < 0.01, after correction with AlphaSim). In addition, the fALFF values in the right cerebellum were positively correlated with the Unified PD Rating Scale (UPDRS) motor scores (r = 0.51, P < 0.05, uncorrected) and the change in

  3. Lack of effects of vagus nerve stimulation on drug-resistant epilepsy in eight pediatric patients with autism spectrum disorders: a prospective 2-year follow-up study.

    PubMed

    Danielsson, Susanna; Viggedal, Gerd; Gillberg, Christopher; Olsson, Ingrid

    2008-02-01

    Vagus nerve stimulation (VNS) therapy has been reported to reduce seizure frequency in some children with drug-resistant epilepsy who are not suitable candidates for epilepsy surgery. It has been suggested that there may be positive cognitive and/or behavioral effects independent of seizure control. We describe the effects of VNS with respect to seizure frequency, cognition, and autistic symptoms and behavior in eight children and adolescents with medically intractable epilepsy and autism. In comparison to baseline, seizure frequency had not decreased in anyone in our series at the 2-year follow-up. In three cases, minor improvements in general functioning were noted, but there were no positive cognitive effects. This open prospective pilot study highlights the need for more prospective studies to prevent false expectations of improvement in this severely disabled group.

  4. Two phase detonation studies conducted in 1971

    NASA Technical Reports Server (NTRS)

    Nicholls, J. A.

    1972-01-01

    A report is presented describing the research conducted on five phases: (1) ignition of fuel drops by a shock wave and passage of a shock wave over a burning drop, (2) the energy release pattern of a two-phase detonation with controlled drop sizes, (3) the attenuation of shock and detonation waves passing over an acoustic liner, (4) experimental and theoretical studies of film detonations, and (5) a simplified analytical model of a rotating two-phase detonation wave in a rocket motor.

  5. Effects of enzyme replacement therapy on five patients with advanced late-onset glycogen storage disease type II: a 2-year follow-up study.

    PubMed

    Furusawa, Yoshihiko; Mori-Yoshimura, Madoka; Yamamoto, Toshiyuki; Sakamoto, Chikako; Wakita, Mizuki; Kobayashi, Yoko; Fukumoto, Yutaka; Oya, Yasushi; Fukuda, Tokiko; Sugie, Hideo; Hayashi, Yukiko K; Nishino, Ichizo; Nonaka, Ikuya; Murata, Miho

    2012-03-01

    We examined the efficacy of 2-year enzyme replacement therapy (ERT) using recombinant human α-glucosidase (GAA; Myozyme®) in five long-term ventilator-dependent adults and aged patients with advanced, late-onset glycogen storage disease type II (GSDII, also known as Pompe disease). Although all patients had advanced respiratory failure and were ventilator-dependent for more than 6 years, four showed obvious improvements in muscle strength, pulmonary function, and activities of daily living after ERT. Improvement in each parameter was more prominent in the first year than in the second year. Values in the second year were still significantly better than those at study entry and indicate stabilization in the clinical status of all patients. These results suggest that ERT continues to be effective in the second year of treatment even in patients suffering from advanced late-onset GSDII disease with severe respiratory failure.

  6. Do deviant peer associations mediate the contributions of self-esteem to problem behavior during early adolescence? A 2-year longitudinal study.

    PubMed

    DuBois, David L; Silverthorn, Naida

    2004-06-01

    We investigated deviant peer associations as a mediator of the influences of general and peer-oriented self-esteem on problem behavior using data from a 2-year longitudinal study of 350 young adolescents. Measures of problem behavior included substance use (alcohol use, smoking) and antisocial behavior (fighting, stealing). Using latent growth curve modeling and covariance structure analysis, an extension of a model proposed by DuBois et al. (2002) was evaluated for each type of problem behavior. Findings revealed that lower general self-esteem and greater peer orientation in self-esteem each predicted deviant associations with peers and that deviant peer associations, in turn, were associated with higher levels and rates of change in problem behavior. Deviant peer associations mediated the associations of general and peer-oriented self-esteem with levels and rates of change in problem behavior such that direct paths from self-esteem to problem behavior generally were nonsignificant.

  7. Associations Among Symptoms of Autism, Symptoms of Depression and Executive Functions in Children with High-Functioning Autism: A 2 Year Follow-Up Study.

    PubMed

    Andersen, Per Normann; Skogli, Erik Winther; Hovik, Kjell Tore; Egeland, Jens; Øie, Merete

    2015-08-01

    This study investigated the course of and association among changes in autism symptoms, depression symptoms and executive functions (EF) in children with high-functioning autism (HFA). Thirty-four children with HFA and 45 typically developing children (age 9-16) were assessed at baseline and after 2 years. Children with HFA had impaired scores on all measures at both time points. According to parent reports, depressive symptoms decreased over time, while EF improved and autism symptoms were stable. Children's reports did not reveal less depressive symptoms over time. A positive association was found only between changes in autism symptoms and changes in symptoms of depression. A possible implication is that interventions aimed at either autism symptoms or symptoms of depression may improve the other.

  8. Real-Life ILUVIEN (Fluocinolone Acetonide) Case Study: Rapid Drying of the Macula and Improved Vision within 2 Years after Therapy Initiation

    PubMed Central

    Quhill, Hibba; Quhill, Fahd

    2016-01-01

    Importance A case showing sustained structural and functional responses 2 years after a single treatment with ILUVIEN (0.2 µg/day fluocinolone acetonide, FAc) despite suboptimal responses to ranibizumab. Observations A 68-year-old female patient with diabetic macular oedema (DME) from type 2 diabetes mellitus was first diagnosed in October 2010 and had a baseline visual acuity (VA) of 46 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in the left eye. Central foveal thickness (CFT) was 712 microns. The patient was treated with 11 intravitreal injections of ranibizumab (5 in combination with a small-interfering RNA agent), and by March 2014, VA and CFT were largely unchanged (55 ETDRS letters and 774 microns). The patient was treated with ILUVIEN as she had a pseudophakic lens and a clearly suboptimal response to the prior therapy with ranibizumab. An implant releasing FAc at a dosage of 0.2 µg/day was administered in March 2014, and the optical coherence tomography indicated that the macula was dry after 7 days (CFT was below 300 microns). This was sustained at 6, 12, and 24 months after the treatment. VA improved by 5 letters within 7 days and by 15 letters within 14 days, and this was maintained after 24 months. Throughout the duration of this study, the intraocular pressure was ≤22 mm Hg, and no glaucoma medication was administered. Conclusions and Relevance In real-life UK practice, this DME patient showed a suboptimal response to multiple intravitreal injections of ranibizumab. When subsequently treated with a single injection of ILUVIEN, there were large and rapid improvements in VA and CFT that were maintained for the following 2 years. PMID:28203186

  9. Social Development:: 2 Year Olds

    MedlinePlus

    ... Español Text Size Email Print Share Social Development: 2 Year Olds Page Content Article Body By nature, ... probably are acting the same way. At age two, children view the world almost exclusively through their ...

  10. Baseline increased 18F-fluoride uptake lesions at vertebral corners on positron emission tomography predict new syndesmophyte development in ankylosing spondylitis: a 2-year longitudinal study.

    PubMed

    Park, Eun-Kyoung; Pak, Kyoungjune; Park, Ji-Heh; Kim, Keunyoung; Kim, Seong-Jang; Kim, In-Joo; Kim, Geun-Tae; Lee, Seung-Geun

    2017-02-02

    The goal of this study was to demonstrate whether increased 18F-fluoride uptake lesions on positron emission tomography (PET) scan can predict new syndesmophyte development in patients with ankylosing spondylitis (AS). In 12 AS patients, 18F-fluoride PET and magnetic resonance imaging (MRI) was performed at baseline, and radiography was performed at baseline and the 2-year follow-up. The following data were recorded: the presence of increased 18F-fluoride uptake lesions on PET defined as an uptake greater than the uptake in the adjacent normal vertebral body; acute (type A) and advanced (type B) corner inflammatory lesions (CILs) and fat lesions on MRI; and syndesmophytes on radiography. Of 231 anterior vertebral corners without syndesmophyte at baseline, 13 type A CILs (5.5%), 2 type B CILs (0.9%), and 20 fat lesions (8.7%) on MRI and six increased fluoride uptake lesions (2.6%) on PET were observed. At the 2-year follow-up, 16 new syndesmophytes (6.9%) in eight AS patients (66.7%) occurred. New syndesmophytes developed significantly more frequently in anterior vertebral corners with increased 18F-fluoride uptake lesions (50%) or fat lesions (25%) at baseline than in those without such lesions (5.8 and 5.2%; p = 0.005 and p = 0.007, respectively). After adjusting confounding factors, baseline increased 18F-fluoride uptake lesions was independently associated with new syndesmophytes development (OR 13.8, 95% CI 1.5-124.3, p = 0.019). Fat lesions were also associated with new syndesmophytes formation. Our data suggest that 18F-fluoride PET may be applied to identify AS patients with high risk of future syndesmophyte formation.

  11. CCL2, CCL18 and sIL-4R in renal, meningeal and pulmonary TB; a 2 year study of patients and contacts.

    PubMed

    Mendez, Armando; Hernandez-Pando, Rogelio; Contreras, Salvador; Aguilar, Diana; Rook, Graham A W

    2011-03-01

    The role of Th2 cytokines and Th2-associated chemokines in tuberculosis (TB) remains controversial, though in Mexico a polymorphism causing increased production of CCL2 is a risk factor. We studied levels of the Th2-associated chemokines CCL2 and CCL18, circulating soluble IL-4 receptors (sIL-4R), IL-4 and the inhibitory splice variant of IL-4 (IL-4δ2) in a cohort of patients with pulmonary TB and their healthy contacts. These were followed for 2 years during which time 10 contacts developed pulmonary TB. Results were compared with measurements made in renal and meningeal TB, and in disease controls with bacterial pneumonias or Dengue fever that have large Th2 components. In these disease controls both chemokines were significantly raised. They were also very significantly raised in all forms of TB, irrespective of age or disease site. Levels of CCL18 were raised least in meningeal TB, and most in pulmonary patients with long histories, when levels were similar to those in disease controls. Levels of CCL2, although also raised in all three forms of TB, were negatively correlated with CCL18. We found that levels of sIL-4R were strikingly reduced in all forms of TB, particularly meningeal. Contacts who progressed could not be distinguished from contacts who remained healthy at 2 years in terms of IL-4, sIL-4R, CCL2 or CCL18. However contacts had raised expression of IL-4δ2 as previously found. These results indicate vigorous and previously unrecorded activity within the Th2 axis, and further investigation is warranted.

  12. Conducting a multi family member interview study.

    PubMed

    Reczek, Corinne

    2014-06-01

    Family researchers have long recognized the utility of incorporating interview data from multiple family members. Yet, relatively few contemporary scholars utilize such an approach due to methodological underdevelopment. This article contributes to family scholarship by providing a roadmap for developing and executing in-depth interview studies that include more than one family member. Specifically, it outlines the epistemological frames that most commonly underlie this approach, illustrates thematic research questions that it best addresses, and critically reviews the best methodological practices of conducting research with this approach. The three most common approaches are addressed in depth: separate interviews with each family member, dyadic or group interviews with multiple family members, and a combined approach that uses separate and dyadic or group interviews. This article speaks to family scholars who are at the beginning stages of their research project but are unsure of the best qualitative approach to answer a given research question.

  13. Time to remission for eating disorder patients: a 2(1/2)-year follow-up study of outcome and predictors.

    PubMed

    Clausen, Loa

    2008-01-01

    The aim of the present study was to analyse outcome, time to remission, and predictors of time to remission in a cohort of Danish eating disorder patients. Seventy-eight patients (35 anorexic, 30 bulimic and 13 unspecified eating disorder patients) were interviewed 2(1/2) years after initial assessment. Method of assessment was Eating Disorder Examination (EDE), Longitudinal Interval Follow-up Evaluation of Eating Disorders (LIFE-EAT-II), Eating Disorder Inventory (EDI), Symptom Check List (SCL-90R), Present State Examination (PSE) and the Structured Clinical Interview for DSM-III-R Axis-II (SCID-II). Method of analysis was Kaplan-Meier estimate of survival, Log Rank test and Cox regression analysis. In total 48.7% reached remission with mean time to remission at 27 months. A trend difference between the diagnostic groups when measuring time to remission was found, i.e. patients with unspecified eating disorders remitted faster than bulimic (BN) patients who in turn remitted faster than anorexic (AN) patients. Body mass index (BMI) at baseline was the best predictor of time to remission for the total sample. Predictors differed when looking at diagnostic groups separately. Final outcome was comparable with earlier studies while relapse frequency was low. Patients with AN remitted faster than found in earlier survival analysis studies, while the remission rate for BN patients was comparable with earlier studies. Despite the prognostic value of BMI for the total sample, predictor analysis implied more disorder diversity than homogeneity.

  14. Acquired hemophilia A in the United Kingdom: a 2-year national surveillance study by the United Kingdom Haemophilia Centre Doctors' Organisation.

    PubMed

    Collins, Peter W; Hirsch, Sybil; Baglin, Trevor P; Dolan, Gerard; Hanley, John; Makris, Michael; Keeling, David M; Liesner, Ri; Brown, Simon A; Hay, Charles R M

    2007-03-01

    Acquired hemophilia A is a severe bleeding disorder caused by an autoantibody to factor VIII. Previous reports have focused on referral center patients and it is unclear whether these findings are generally applicable. To improve understanding of the disease, a 2-year observational study was established to identify and characterize the presenting features and outcome of all patients with acquired hemophilia A in the United Kingdom. This allowed a consecutive cohort of patients, unbiased by referral or reporting practice, to be studied. A total of 172 patients with a median age of 78 years were identified, an incidence of 1.48/million/y. The cohort was significantly older than previously reported series, but bleeding manifestations and underlying diseases were similar. Bleeding was the cause of death in 9% of the cohort and remained a risk until the inhibitor had been eradicated. There was no difference in inhibitor eradication or mortality between patients treated with steroids alone and a combination of steroids and cytotoxic agents. Relapse of the inhibitor was observed in 20% of the patients who had attained first complete remission. The data provide the most complete description of acquired hemophilia A available and are applicable to patients presenting to all centers.

  15. Bacterial community shift is induced by dynamic environmental parameters in a changing coastal ecosystem (northern Adriatic, northeastern Mediterranean Sea)--a 2-year time-series study.

    PubMed

    Tinta, T; Vojvoda, J; Mozetič, P; Talaber, I; Vodopivec, M; Malfatti, F; Turk, V

    2015-10-01

    The potential link between the microbial dynamics and the environmental parameters was investigated in a semi-enclosed and highly dynamic coastal system (Gulf of Trieste, northern Adriatic Sea, NE Mediterranean Sea). Our comprehensive 2-year time-series study showed that despite the shallowness of this area, there was a significant difference between the surface and the bottom bacterial community structure. The bottom bacterial community was more diverse than the surface one and influenced by sediment re-suspension. The surface seawater temperature had a profound effect on bacterial productivity, while the bacterial community structure was more affected by freshwater-borne nutrients and phytoplankton blooms. Phytoplankton blooms caused an increase of Gammaproteobacteria (Alteromonadaceae, SAR86 and Vibrionaceae) and shift in dominance from SAR11 to Rhodobacteraceae taxon at the surface. Our results propose the importance of the water mass movements as drivers of freshwater-borne nutrients and of allochthonous microbial taxa. This study emphasizes the prediction power based on association networks analyses that are fed with long-term measurements of microbial and environmental parameters. These interaction maps offer valuable insights into the response of marine ecosystem to climate- and anthropogenic-driven stressors.

  16. Twenty-four mini-pool HCV RNA screening outside a blood transfusion setting: results of a 2-year prospective study.

    PubMed

    Seme, Katja; Mocilnik, Tina; Fujs, Kristina; Babic, Dunja Z; Todorović, Aleksandra; Fras-Stefan, Tamara; Poljak, Mario

    2007-03-01

    The usefulness of 24 mini-pool hepatitis C virus (HCV) RNA screening was evaluated in a 2-year prospective study carried out on a total of 6432 consecutive anti-HCV negative specimens in a routine diagnostic laboratory setting. A total of 268 mini-pools were tested using an automated commercial PCR assay for qualitative detection of HCV RNA, with a lower limit of detection of 50 IU/ml. Eighteen (0.28%) anti-HCV negative/HCV RNA positive serum samples obtained from 12 patients (all intravenous drug users), were detected. Ten patients responded to an invitation for follow-up testing. Five, three and one patient seroconverted in the first, second and third follow-up sample, respectively. One patient had not seroconverted by the end of the study period. The interval between the first HCV RNA positive sample and the first anti-HCV positive samples was 24-192 days. The costs of detecting a single anti-HCV negative/HCV RNA positive sample and a single anti-HCV negative/HCV RNA positive patient using the 24 mini-pool HCV RNA screening strategy were estimated to be around euro 643 and 965, respectively. It was shown that screening for HCV infection using the 24 mini-pool HCV RNA screening strategy can also be both useful and cost effective outside a blood transfusion setting.

  17. Influence of Anti-TNF and Disease Modifying Antirheumatic Drugs Therapy on Pulmonary Forced Vital Capacity Associated to Ankylosing Spondylitis: A 2-Year Follow-Up Observational Study

    PubMed Central

    Rocha-Muñoz, Alberto Daniel; Brambila-Tapia, Aniel Jessica Leticia; Zavala-Cerna, María Guadalupe; Vásquez-Jiménez, José Clemente; De la Cerda-Trujillo, Liliana Faviola; Vázquez-Del Mercado, Mónica; Rodriguez-Jimenez, Norma Alejandra; Díaz-Rizo, Valeria; Díaz-González, Viviana; Cardona-Muñoz, Ernesto German; Dávalos-Rodríguez, Ingrid Patricia; Salazar-Paramo, Mario; Gamez-Nava, Jorge Ivan; Nava-Zavala, Arnulfo Hernan; Gonzalez-Lopez, Laura

    2015-01-01

    Objective. To evaluate the effect of anti-TNF agents plus synthetic disease modifying antirheumatic drugs (DMARDs) versus DMARDs alone for ankylosing spondylitis (AS) with reduced pulmonary function vital capacity (FVC%). Methods. In an observational study, we included AS who had FVC% <80% at baseline. Twenty patients were taking DMARDs and 16 received anti-TNF + DMARDs. Outcome measures: changes in FVC%, BASDAI, BASFI, 6-minute walk test (6MWT), Borg scale after 6MWT, and St. George's Respiratory Questionnaire at 24 months. Results. Both DMARDs and anti-TNF + DMARDs groups had similar baseline values in FVC%. Significant improvement was achieved with anti-TNF + DMARDs in FVC%, at 24 months, when compared to DMARDs alone (P = 0.04). Similarly, patients in anti-TNF + DMARDs group had greater improvement in BASDAI, BASFI, Borg scale, and 6MWT when compared to DMARDs alone. After 2 years of follow-up, 14/16 (87.5%) in the anti-TNF + DMARDs group achieved the primary outcome: FVC% ≥80%, compared with 11/20 (55%) in the DMARDs group (P = 0.04). Conclusions. Patients with anti-TNF + DMARDs had a greater improvement in FVC% and cardiopulmonary scales at 24 months compared with DMARDs. This preliminary study supports the fact that anti-TNF agents may offer additional benefits compared to DMARDs in patients with AS who have reduced FVC%. PMID:26078986

  18. A phase 1 study of obinutuzumab induction followed by 2 years of maintenance in patients with relapsed CD20-positive B-cell malignancies.

    PubMed

    Sehn, Laurie H; Assouline, Sarit E; Stewart, Douglas A; Mangel, Joy; Gascoyne, Randy D; Fine, Gregg; Frances-Lasserre, Susan; Carlile, David J; Crump, Michael

    2012-05-31

    This phase 1 study evaluated the safety, tolerability, pharmacokinetics, and antitumor activity of obinutuzumab (GA101), a glycoengineered type II anti-CD20 monoclonal antibody administered as induction followed by 2 years of maintenance. Cohorts of 3 to 6 patients received obinutuzumab (200-2000 mg) intravenously weekly for 4 weeks. Patients with a complete or partial response (or stable disease and clinical benefit) continued to receive obinutuzumab every 3 months, for a maximum of 8 doses. Twenty-two patients with relapsed CD20-positive non-Hodgkin lymphoma or chronic lymphocytic leukemia with an indication for treatment and no therapy of higher priority were enrolled. Patients received a median of 4 prior regimens; 86% had received at least 1 rituximab-containing regimen. No dose-limiting or unexpected AEs were observed. Infusion-related reactions were most common (all grades, 73%; grade 3/4, 18%), followed by infection (32%), pyrexia (23%), neutropenia (23%), headache (18%), and nausea (18%). At end of induction, 5 (23%) patients achieved partial responses and 12 (54%) had stable disease. Eight patients received maintenance; best overall response was 32% (6 partial responses/1 complete response). Obinutuzumab induction and maintenance therapy was well tolerated with promising efficacy in this heterogeneous, highly pretreated population and warrants further investigation. This study was registered at www.clinicaltrials.gov (identifier NCT00576758).

  19. Observation on therapeutic efficacy of ursodeoxycholic acid in Chinese patients with primary biliary cirrhosis: a 2-year follow-up study.

    PubMed

    Zhu, Jiangyi; Shi, Yongquan; Zhou, Xinmin; Li, Zengshan; Huang, Xiaofeng; Han, Zheyi; Wang, Jianhong; Wang, Ruian; Ding, Jie; Wu, Kaichun; Han, Ying; Fan, Daiming

    2013-06-01

    The efficacy of ursodeoxycholic acid (UDCA) on long-term outcome of primary biliary cirrhosis (PBC) has been less documented in Chinese cohort. We aimed to assess the therapeutic effect of UDCA on Chinese patients with PBC. In the present study, 67 patients with PBC were treated with UDCA (13-15 mg·kg(-1)·day(-1)) and followed up for 2 years to evaluate the changes of symptoms, laboratory values and histological features. As the results indicated, fatigue and pruritus were obviously improved by UDCA, particularly in patients with mild or moderate symptoms. The alkaline phosphatase and γ-glutamyl transpetidase levels significantly declined at year 2 comparing to baseline values, with the most profound effects achieved in patients at stage 2. The levels of alanine aminotransferase and aspartate aminotransferase significantly decreased whereas serum bilirubin and immunoglobulin M levels exhibited no significant change. Histological feature was stable in patients at stages 1-2 but still progressed in patients at stages 3-4. The biochemical response of patients at stage 2 was much better than that of patients at stages 3-4. These data suggest that, when treated in earlier stage, patients in long-term administration of UDCA can gain favorable results not only on symptoms and biochemical responses but also on histology. It is also indicated that later histological stage, bad biochemical response and severe symptom may be indicators of poor prognosis for UDCA therapy.

  20. Violence and Abuse Against Women Who Have Attempted Suicide by Deliberate Self-Poisoning: A 2-Year Follow-Up Study in Iran.

    PubMed

    Hassanian-Moghaddam, Hossein; Zamani, Nasim; Sarjami, Saeedeh

    2016-04-01

    Sources of data about the occurrence of domestic violence are scarce in Iran. The aim of this study was to evaluate the behavioral effects of different types of domestic violence on women who had attempted suicide by deliberate self-poisoning (DSP). A total of 195 women who had attempted suicide by DSP in response to "violence and abuse" were followed up for 2 years. The most common type of violence, as mentioned by the women themselves as the motive of self-poisoning, was physical abuse (92%) followed by verbal abuse (2.1%), multi-abuses (2.1%), emotional abuse (1.6%), and sexual abuse (1.1%). Suicidal ideation and attempt were more common in those who were consulted sometime after they had initially presented to the hospital with DSP or those who had suffered repeated domestic abuse. It was concluded that invention of methods other than the current consultation system is necessary to prevent repeated suicide attempts among abused women in Iran.

  1. The performance of moss, grass, and 1- and 2-year old spruce needles as bioindicators of contamination: a comparative study at the scale of the Czech Republic.

    PubMed

    Suchara, Ivan; Sucharova, Julie; Hola, Marie; Reimann, Clemens; Boyd, Rognvald; Filzmoser, Peter; Englmaier, Peter

    2011-05-01

    Moss (Pleurozium schreberi), grass (Avenella flexuosa), and 1- and 2-year old spruce (Picea abies) needles were collected over the territory of the Czech Republic at an average sample density of 1 site per 290km(2). The samples were analysed for 39 elements (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Hg, K, La, Li, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, Rb, S, Sb, Se, Sn, Sr, Th, Tl, U, V, Y and Zn) using ICP-MS and ICP-AES techniques (the major nutrients Ca, K, Mg and Na were not analysed in moss). Moss showed by far the highest element concentrations for most elements. Exceptions were Ba (spruce), Mn (spruce), Mo (grass), Ni (spruce), Rb (grass) and S (grass). Regional distribution maps and spatial trend analysis were used to study the suitability of the four materials as bioindicators of anthropogenic contamination. The highly industrialised areas in the north-west and the far east of the country and several more local contamination sources were indicated in the distribution maps of one or several sample materials. At the scale of the whole country moss was the best indicator of known contamination sources. However, on a more local scale, it appeared that spruce needles were especially well suited for detection of urban contamination.

  2. Working memory arrest in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder: results from a 2-year longitudinal study.

    PubMed

    Andersen, Per N; Skogli, Erik W; Hovik, Kjell T; Geurts, Hilde; Egeland, Jens; Øie, Merete

    2015-05-01

    The aim of this study was to analyse the development of verbal working memory in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder and typically developing children. A total of 34 children with high-functioning autism, 72 children with attention-deficit/hyperactivity disorder and 45 typically developing children (age 9-16 years) were included at baseline and followed up approximately 25 months later. The children were given a letter/number sequencing task to assess verbal working memory. The performance of children with high-functioning autism on verbal working memory did not improve after 2 years, while improvement was observed in children with attention-deficit/hyperactivity disorder and typically developing children. The results indicate a different developmental trajectory for verbal working memory in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder and typically developing children. More research is needed to construct a developmental framework more suitable for children with autism spectrum disorder.

  3. A 2-Year Field Study Shows Little Evidence That the Long-Term Planting of Transgenic Insect-Resistant Cotton Affects the Community Structure of Soil Nematodes

    PubMed Central

    Li, Xiaogang; Liu, Biao

    2013-01-01

    Transgenic insect-resistant cotton has been released into the environment for more than a decade in China to effectively control the cotton bollworm (Helicoverpa armigera) and other Lepidoptera. Because of concerns about undesirable ecological side-effects of transgenic crops, it is important to monitor the potential environmental impact of transgenic insect-resistant cotton after commercial release. Our 2-year study included 1 cotton field where non-transgenic cotton had been planted continuously and 2 other cotton fields where transgenic insect-resistant cotton had been planted for different lengths of time since 1997 and since 2002. In 2 consecutive years (2009 and 2010), we took soil samples from 3 cotton fields at 4 different growth stages (seedling, budding, boll-forming and boll-opening stages), collected soil nematodes from soil with the sugar flotation and centrifugation method and identified the soil nematodes to the genus level. The generic composition, individual densities and diversity indices of the soil nematodes did not differ significantly between the 2 transgenic cotton fields and the non-transgenic cotton field, but significant seasonal variation was found in the individual densities of the principal trophic groups and in the diversity indices of the nematodes in all 3 cotton fields. The study used a comparative perspective to monitor the impact of transgenic insect-resistant cotton grown in typical ‘real world’ conditions. The results of the study suggested that more than 10 years of cultivation of transgenic insect-resistant cotton had no significant effects–adverse or otherwise–on soil nematodes. This study provides a theoretical basis for ongoing environmental impact monitoring of transgenic plants. PMID:23613899

  4. Emotional Development: 2 Year Olds

    MedlinePlus

    ... Español Text Size Email Print Share Emotional Development: 2 Year Olds Page Content Article Body It’s so ... to follow the ups and downs of a two-year-old. One moment he’s beaming and friendly; ...

  5. Effect of ONO-5334 on bone mineral density and biochemical markers of bone turnover in postmenopausal osteoporosis: 2-year results from the OCEAN study.

    PubMed

    Eastell, Richard; Nagase, Shinichi; Small, Maria; Boonen, Steven; Spector, Tim; Ohyama, Michiyo; Kuwayama, Tomohiro; Deacon, Steve

    2014-02-01

    Cathepsin K inhibitors, such as ONO-5334, are being developed for the treatment of postmenopausal osteoporosis. However, their relative effects on bone resorption and formation, and how quickly the effects resolve after treatment cessation, are uncertain. The aim of this study was to examine the efficacy and safety of 24-month treatment with ONO-5334 and to assess the effect of treatment cessation over 2 months. We studied 197 postmenopausal women with osteoporosis or osteopenia with one fragility fracture. Patients were randomized to ONO-5334 50 mg twice daily, 100 mg or 300 mg once daily, alendronate 70 mg once weekly (positive control), or placebo for 24 months. After 24 months, all ONO-5334 doses were associated with increased bone mineral density (BMD) for lumbar spine, total hip, and femoral neck (p < 0.001). ONO-5334 300 mg significantly suppressed the bone-resorption markers urinary (u) NTX and serum and uCTX-I throughout 24 months of treatment and to a similar extent as alendronate; other resorption marker levels remained similar to placebo (fDPD for ONO-5334 300 mg qd) or were increased (ICTP, TRAP5b, all ONO-5334 doses). Levels of B-ALP and PINP were suppressed in all groups (including placebo) for approximately 6 months but then increased for ONO-5334 to close to baseline levels by 12 to 24 months. On treatment cessation, there were increases above baseline in uCTX-I, uNTX, and TRAP5b, and decreases in ICTP and fDPD. There were no clinically relevant safety concerns. Cathepsin K inhibition with ONO-5334 resulted in decreases in most resorption markers over 2 years but did not decrease most bone formation markers. This was associated with an increase in BMD; the effect on biochemical markers was rapidly reversible on treatment cessation.

  6. 40 CFR 792.130 - Conduct of a study.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Conduct of a study. 792.130 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Protocol for and Conduct of A Study § 792.130 Conduct of a study. (a) The study shall be conducted in accordance with the protocol. (b) The test...

  7. 40 CFR 792.130 - Conduct of a study.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Conduct of a study. 792.130 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Protocol for and Conduct of A Study § 792.130 Conduct of a study. (a) The study shall be conducted in accordance with the protocol. (b) The test...

  8. 40 CFR 792.130 - Conduct of a study.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Conduct of a study. 792.130 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Protocol for and Conduct of A Study § 792.130 Conduct of a study. (a) The study shall be conducted in accordance with the protocol. (b) The test...

  9. 40 CFR 792.130 - Conduct of a study.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Conduct of a study. 792.130 Section 792... (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Protocol for and Conduct of A Study § 792.130 Conduct of a study. (a) The study shall be conducted in accordance with the protocol. (b) The test systems shall...

  10. 40 CFR 792.130 - Conduct of a study.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 33 2013-07-01 2013-07-01 false Conduct of a study. 792.130 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Protocol for and Conduct of A Study § 792.130 Conduct of a study. (a) The study shall be conducted in accordance with the protocol. (b) The test...

  11. Neuroscience Investigations: An Overview of Studies Conducted

    NASA Technical Reports Server (NTRS)

    Reschke, Millard F.

    1999-01-01

    The neural processes that mediate human spatial orientation and adaptive changes occurring in response to the sensory rearrangement encountered during orbital flight are primarily studied through second and third order responses. In the Extended Duration Orbiter Medical Project (EDOMP) neuroscience investigations, the following were measured: (1) eye movements during acquisition of either static or moving visual targets, (2) postural and locomotor responses provoked by unexpected movement of the support surface, changes in the interaction of visual, proprioceptive, and vestibular information, changes in the major postural muscles via descending pathways, or changes in locomotor pathways, and (3) verbal reports of perceived self-orientation and self-motion which enhance and complement conclusions drawn from the analysis of oculomotor, postural, and locomotor responses. In spaceflight operations, spatial orientation can be defined as situational awareness, where crew member perception of attitude, position, or motion of the spacecraft or other objects in three-dimensional space, including orientation of one's own body, is congruent with actual physical events. Perception of spatial orientation is determined by integrating information from several sensory modalities. This involves higher levels of processing within the central nervous system that control eye movements, locomotion, and stable posture. Spaceflight operational problems occur when responses to the incorrectly perceived spatial orientation are compensatory in nature. Neuroscience investigations were conducted in conjunction with U. S. Space Shuttle flights to evaluate possible changes in the ability of an astronaut to land the Shuttle or effectively perform an emergency post-landing egress following microgravity adaptation during space flights of variable length. While the results of various sensory motor and spatial orientation tests could have an impact on future space flights, our knowledge of

  12. Oral health-related quality of life in partially edentulous patients before and after implant therapy: a 2-year longitudinal study

    PubMed Central

    BRAMANTI, E.; MATACENA, G.; CECCHETTI, F.; ARCURI, C.; CICCIÙ, M.

    2013-01-01

    SUMMARY Objectives. The aim of this study was to measure the Oral Health-Related Quality of Life (OHRQoL) before and after a prosthodontic implant therapy so to determine the physical and psychological impact of implant-supported fixed partial dentures (IFPD) rehabilitation among edentulous patients. Methods. 50 partially edentulous patients aged 40–70 years, treated with IFPD, completed the OHRQoL questionnaire before the implant surgery (Time 0) and 2 years after their whole implant-prosthetic rehabilitation (Time 1). The questionnaire was proposed in a short version of Oral Health Impact Profile (OHIP-14, range 0–56) and analyzed through the ‘additive method’. We evaluated statistical mean, standard deviation, median, variance and mode of all OHIP-14 domains and the statistical significance about oral changes at Time 0 and Time 1 using the Chi-square test (p-values < 0.05). Results. Patients reported significant changes in mean OHIP scores (Time 0: 2.15; Time 1: 0.65; p < 0.01). The most prevalently affected domain was “functional limitation”, followed by “psychological discomfort” and “physical pain”. There were no significant differences dependent on age, gender and antagonistic teeth (p > 0.05). Patients with I and IV Kennedy’s class edentulism showed better improvement (p < 0.05). Conclusions. Preoperative and post-treatment assessments of OHRQoL exhibited significant differences. The IFPD treatment had a positive effect on the OHRQoL, which improved better in patients with I and IV Kennedy’s edentulous class. PMID:24175052

  13. Scaling up family medicine training in Gezira, Sudan – a 2-year in-service master programme using modern information and communication technology: a survey study

    PubMed Central

    2014-01-01

    Background In 2010 the Gezira Family Medicine Project (GFMP) was initiated in Gezira state, Sudan, designed as an in-service training model. The project is a collaboration project between the University of Gezira, which aims to provide a 2-year master’s programme in family medicine for practicing doctors, and the Ministry of Health, which facilitates service provision and funds the training programme. This paper presents the programme, the teaching environment, and the first batch of candidates enrolled. Methods In this study a self-administered questionnaire was used to collect baseline data at the start of the project from doctors who joined the programme. A checklist was also used to assess the health centres where they work. A total of 188 out of 207 doctors responded (91%), while data were gathered from all 158 health centres (100%) staffed by the programme candidates. Results The Gezira model of in-service family medicine training has succeeded in recruiting 207 candidates in its first batch, providing health services in 158 centres, of which 84 had never been served by a doctor before. The curriculum is community oriented. The mean age of doctors was 32.5 years, 57% were males, and 32% were graduates from the University of Gezira. Respondents stated high confidence in practicing some skills such as asthma management and post-abortion uterine evacuation. They were least confident in other skills such as managing depression or inserting an intrauterine device. The majority of health centres was poorly equipped for management of noncommunicable diseases, as only 10% had an electrocardiography machine (ECG), 5% had spirometer, and 1% had a defibrillator. Conclusions The Gezira model has responded to local health system needs. Use of modern information and communication technology is used to facilitate both health service provision and training. The GFMP represents an example of a large-volume scaling-up programme of family medicine in Africa. PMID:24443978

  14. Anemia on Admission Is an Independent Predictor of Long-Term Mortality in Hip Fracture Population: A Prospective Study With 2-Year Follow-Up.

    PubMed

    Zhang, Licheng; Yin, Pengbin; Lv, Houchen; Long, Anhua; Gao, Yuan; Zhang, Lihai; Tang, Peifu

    2016-02-01

    Anemia is a disputable factor for long-term mortality in hip fracture population in previous studies. Previous studies indicated that the level of hemoglobin (Hb) might fluctuate due to various factors, such as comorbidities and in-hospital interventions, and the changing level of Hb, may lead to discordance diagnosis of anemia and thus to the conflicting conclusions on prognostic value of anemia. So in this study, we aim to compare factors affecting the diagnosis of anemia at different time-points, admission, postoperation, and discharge, and to determine which the time point is most suitable for mortality prediction.This prospective cohort study included 1330 hip fracture patients from 1 January 2000 to 18 November 2012. Hb levels at 3 different time points, such as admission, postoperation, and discharge, were collected and used to stratify the cohort into anemia and nonanemia groups. Candidate factors including commodities, perioperative factors, blood transfusion, and other in-hospital interventions were collected before discharge. Logistic regression analyses were performed to detect risk factors for anemia for the 3 time points separately. Kaplan-Meier and multivariate Cox regression analyses were used to evaluate the association between anemia and 2-year mortality.Factors affecting the diagnosis of anemia were different for the 3 time points. Age, female sex, American Society of Anesthesiologists score (ASA), and intertrochanteric fracture were associated with admission anemia, while surgical procedure, surgical duration, blood transfusion, blood loss during the operation, and drainage volume were major risk factors for postoperation anemia. Cox proportional-hazards regression analysis suggested that the risk of all-cause mortality was higher in the anemia group on admission (1.680, 95%CI: 1.201-2.350, P < 0.01), but not postoperation or on discharge, after adjustment for confounding factors.Our study showed that risk factors for anemia varied at

  15. Thermal and electrical contact conductance studies

    NASA Technical Reports Server (NTRS)

    Vansciver, S. W.; Nilles, M.

    1985-01-01

    Prediction of electrical and thermal contact resistance for pressed, nominally flat contacts is complicated by the large number of variables which influence contact formation. This is reflected in experimental results as a wide variation in contact resistances, spanning up to six orders of magnitude. A series of experiments were performed to observe the effects of oxidation and surface roughness on contact resistance. Electrical contact resistance and thermal contact conductance from 4 to 290 K on OFHC Cu contacts are reported. Electrical contact resistance was measured with a 4-wire DC technique. Thermal contact conductance was determined by steady-state longitudinal heat flow. Corrections for the bulk contribution ot the overall measured resistance were made, with the remaining resistance due solely to the presence of the contact.

  16. Nuts and bolts of conducting feasibility studies.

    PubMed

    Tickle-Degnen, Linda

    2013-01-01

    Many factors can affect the successful implementation and validity of intervention studies. A primary purpose of feasibility and pilot studies is to assess the potential for successful implementation of the proposed main intervention studies and to reduce threats to the validity of these studies. This article describes a typology to guide the aims of feasibility and pilot studies designed to support the development of randomized controlled trials and provides an example of the studies underlying the development of one rehabilitation trial. The purpose of most feasibility and pilot studies should be to describe information and evidence related to the successful implementation and validity of a planned main trial. Null hypothesis significance testing is not appropriate for these studies unless the sample size is properly powered. The primary tests of the intervention effectiveness hypotheses should occur in the main study, not in the studies that are serving as feasibility or pilot studies.

  17. Gas release and conductivity modification studies

    NASA Technical Reports Server (NTRS)

    Linson, L. M.; Baxter, D. C.

    1979-01-01

    The behavior of gas clouds produced by releases from orbital velocity in either a point release or venting mode is described by the modification of snowplow equations valid in an intermediate altitude regime. Quantitative estimates are produced for the time dependence of the radius of the cloud, the average internal energy, the translational velocity, and the distance traveled. The dependence of these quantities on the assumed density profile, the internal energy of the gas, and the ratio of specific heats is examined. The new feature is the inclusion of the effect of the large orbital velocity. The resulting gas cloud models are used to calculate the characteristics of the field line integrated Pedersen conductivity enhancements that would be produced by the release of barium thermite at orbital velocity in either the point release or venting modes as a function of release altitude and chemical payload weight.

  18. 40 CFR 160.130 - Conduct of a study.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date...

  19. 40 CFR 160.130 - Conduct of a study.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date...

  20. 40 CFR 160.130 - Conduct of a study.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date...

  1. 40 CFR 160.130 - Conduct of a study.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date...

  2. 40 CFR 160.130 - Conduct of a study.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date...

  3. Dietary arsenic consumption and urine arsenic in an endemic population: response to improvement of drinking water quality in a 2-year consecutive study.

    PubMed

    Biswas, Anirban; Deb, Debasree; Ghose, Aloke; Du Laing, Gijs; De Neve, Jan; Santra, Subhas Chandra; Guha Mazumder, Debendra Nath

    2014-01-01

    We assessed the association between arsenic intake through water and diet, and arsenic levels in first morning-void urine under variable conditions of water contamination. This was done in a 2-year consecutive study in an endemic population. Exposure of arsenic through water and diet was assessed for participants using arsenic-contaminated water (≥50 μg L(-1)) in a first year (group I) and for participants using water lower in arsenic (<50 μg L(-1)) in the next year (group II). Participants with and without arsenical skin lesions were considered in the statistical analysis. Median dose of arsenic intake through drinking water in groups I and II males was 7.44 and 0.85 μg kg body wt.(-1) day(-1) (p <0.0001). In females, it was 5.3 and 0.63 μg kg body wt.(-1) day(-1) (p <0.0001) for groups I and II, respectively. Arsenic dose through diet was 3.3 and 2.6 μg kg body wt.(-1) day(-1) (p = 0.088) in males and 2.6 and 1.9 μg kg body wt.(-1) day(-1) (p = 0.0081) in females. Median arsenic levels in urine of groups I and II males were 124 and 61 μg L(-1) (p = 0.052) and in females 130 and 52 μg L(-1) (p = 0.0001), respectively. When arsenic levels in the water were reduced to below 50 μg L(-1) (Indian permissible limit), total arsenic intake and arsenic intake through the water significantly decreased, but arsenic uptake through the diet was found to be not significantly affected. Moreover, it was found that drinking water mainly contributed to variations in urine arsenic concentrations. However, differences between male and female participants also indicate that not only arsenic uptake, but also many physiological factors affect arsenic behavior in the body and its excretion. As total median arsenic exposure still often exceeded 3.0 μg kg body wt.(-1) day(-1) (the permissible lower limit established by the Joint Expert Committee on Food Additives) after installation of the drinking water filters, it can be concluded that

  4. 18 CFR 5.15 - Conduct of studies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Conduct of studies. 5... Conduct of studies. (a) Implementation. The potential applicant must gather information and conduct studies as provided for in the approved study plan and schedule. (b) Progress reports. The...

  5. 18 CFR 5.15 - Conduct of studies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Conduct of studies. 5... Conduct of studies. (a) Implementation. The potential applicant must gather information and conduct studies as provided for in the approved study plan and schedule. (b) Progress reports. The...

  6. 18 CFR 5.15 - Conduct of studies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Conduct of studies. 5... Conduct of studies. (a) Implementation. The potential applicant must gather information and conduct studies as provided for in the approved study plan and schedule. (b) Progress reports. The...

  7. 18 CFR 5.15 - Conduct of studies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... to the facts of the case, a demonstration that: (1) Approved studies were not conducted as provided... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Conduct of studies. 5... Conduct of studies. (a) Implementation. The potential applicant must gather information and...

  8. 18 CFR 5.15 - Conduct of studies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... to the facts of the case, a demonstration that: (1) Approved studies were not conducted as provided... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Conduct of studies. 5... Conduct of studies. (a) Implementation. The potential applicant must gather information and...

  9. Etiological Role and Repeated Infections of Sapovirus among Children Aged Less than 2 Years in a Cohort Study in a Peri-urban Community of Peru

    PubMed Central

    Liu, Xiaofang; Jahuira, Helena; Gilman, Robert H.; Alva, Alicia; Cabrera, Lilia; Okamoto, Michiko; Xu, Hang; Windle, Henry J.; Kelleher, Dermot; Varela, Marco; Verastegui, Manuela; Calderon, Maritza; Sanchez, Gerardo; Sarabia, Vanessa; Ballard, Sarah B.; Bern, Caryn; Mayta, Holger; Crabtree, Jean E.; Cama, Vitaliano; Oshitani, Hitoshi

    2016-01-01

    Human sapovirus has been shown to be one of the most important etiologies in pediatric patients with acute diarrhea. However, very limited data are available about the causative roles and epidemiology of sapovirus in community settings. A nested matched case-control study within a birth cohort study of acute diarrhea in a peri-urban community in Peru from 2007 to 2010 was conducted to investigate the attributable fraction (AF) and genetic diversity of sapovirus. By quantitative reverse transcription–real-time PCR (qPCR) sapovirus was detected in 12.4% (37/299) of diarrheal and 5.7% (17/300) of nondiarrheal stools (P = 0.004). The sapovirus AF (7.1%) was higher in the second year (13.2%) than in the first year (1.4%) of life of children. Ten known genotypes and one novel cluster (n = 5) within four genogroups (GI, GII, GIV, and GV) were identified by phylogenetic analysis of a partial VP1 gene. Further sequence analysis of the full VP1 gene revealed a possible novel genotype, tentatively named GII.8. Notably, symptomatic reinfections with different genotypes within the same (n = 3) or different (n = 5) genogroups were observed in eight children. Sapovirus exhibited a high attributable burden for acute gastroenteritis, especially in the second year of life, of children in a Peruvian community. Further large-scale studies are needed to understand better the global burden, genetic diversity, and repeated infections of sapovirus. PMID:27076657

  10. Conductivity and electrical studies of plasticized carboxymethyl cellulose based proton conducting solid biopolymer electrolytes

    NASA Astrophysics Data System (ADS)

    Isa, M. I. N.; Noor, N. A. M.

    2015-12-01

    In this paper, a proton conducting solid biopolymer electrolytes (SBE) comprises of carboxymethyl cellulose (CMC) as polymer host, ammonium thiocyanate (NH4SCN) as doping salt and ethylene carbonate (EC) as plasticizer has been prepared via solution casting technique. Electrical Impedance Spectroscopy (EIS) was carried out to study the conductivity and electrical properties of plasticized CMC-NH4SCN SBE system over a wide range of frequency between 50 Hz and 1 MHz at temperature range of 303 to 353 K. Upon addition of plasticizer into CMC-NH4SCN SBE system, the conductivity increased from 10-5 to 10-2 Scm-1. The highest conductivity was obtained by the electrolyte containing 10 wt.% of EC. The conductivity of plasticized CMC-NH4SCN SBE system by various temperatures obeyed Arrhenius law where the ionic conductivity increased as the temperature increased. The activation energy, Ea was found to decrease with enhancement of EC concentration. Dielectric studies for the highest conductivity electrolyte obeyed non-Debye behavior. The conduction mechanism for the highest conductivity electrolyte was determined by employing Jonsher's universal power law and thus, can be represented by the quantum mechanical tunneling (QMT) model.

  11. Preoperative screening/decolonization for Staphylococcus aureus to prevent orthopedic surgical site infection: prospective cohort study with 2-year follow-up.

    PubMed

    Rao, Nalini; Cannella, Barbara A; Crossett, Lawrence S; Yates, Adolph J; McGough, Richard L; Hamilton, Cindy W

    2011-12-01

    We quantified surgical site infections (SSIs) after preoperative screening/selective decolonization before elective total joint arthroplasty (TJA) with 2-year follow-up and 2 controls. Concurrent controls (n = 2284) were patients of surgeons not participating in screening/decolonization. Preintervention controls (n = 741) were patients of participating surgeons who underwent TJA the previous year. Staphylococcus aureus nasal carriers (321/1285 [25%]) used intranasal mupirocin and chlorhexidine baths as outpatients. Staphylococcal SSIs occurred in no intervention patients (0/321) and 19 concurrent controls. If all SSIs occurred in carriers and 25% of controls were carriers, staphylococcal SSI rate would have been 3.3% in controls (19/571; P = .001). Overall SSI rate decreased from 2.7% (20/741) in preintervention controls to 1.2% (17/1440) in intervention patients (P = .009). Preoperative screening/selective decolonization was associated with fewer SSIs after elective TJA.

  12. Age 2: Findings from the 2-Year-Old Follow-Up of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B). E.D. TAB. NCES 2006-043

    ERIC Educational Resources Information Center

    Mulligan, Gail M.; Flanagan, Kristin Denton

    2006-01-01

    This E.D. TAB is the first report produced using data from the second round of data collection for the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), a study of a nationally representative sample of children born in the year 2001. The report provides descriptive information about these children when they were about 2 years old. It…

  13. Charge transport studies of proton and ion conducting materials

    NASA Astrophysics Data System (ADS)

    Versek, Craig Wm

    The development of a high-throughput impedance spectroscopy instrumentation platform for conductivity characterization of ion transport materials is outlined. Collaborative studies using this system are summarized. Charge conduction mechanisms and conductivity data for small molecule proton conducting liquids, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, and select mixtures of these compounds are documented. Furthermore, proton diffusivity measurements using a Pulse Field Gradient Nuclear Magnetic Resonance (PFG NMR) technique for imidazole and 1,2,3-triazole binary mixtures are compared. Studies of azole functionalized discotic and linear mesogens with conductivity, structural, and thermal characterizations are detailed.

  14. Serum levels of osteoprotegerin and receptor activator of nuclear factor -κB ligand in children with early juvenile idiopathic arthritis: a 2-year prospective controlled study

    PubMed Central

    2010-01-01

    Background The clinical relevance of observations of serum levels of osteoprotegerin (OPG) and receptor activator of nuclear factor -κB ligand (RANKL) in juvenile idiopathic arthritis (JIA) is not clear. To elucidate the potential role of OPG and RANKL in JIA we determined serum levels of OPG and RANKL in patients with early JIA compared to healthy children, and prospectively explored changes in relation to radiographic score, bone and lean mass, severity of the disease, and treatment. Methods Ninety children with early oligoarticular or polyarticular JIA (ages 6-18 years; mean disease duration 19.4 months) and 90 healthy children individually matched for age, sex, race, and county of residence, were examined at baseline and 2-year follow-up. OPG and RANKL were quantified by enzyme-immunoassay. Data were analyzed with the use of t-tests, ANOVA, and multiple regression analyses. Results Serum OPG was significantly lower in patients than controls at baseline, and there was a trend towards higher RANKL and a lower OPG/RANKL ratio. Patients with polyarthritis had significantly higher increments in RANKL from baseline to follow-up, compared to patients with oligoarthritis. RANKL was a significant negative predictor for increments in total body lean mass. Patients who were receiving corticosteroids (CS) or disease-modifying antirheumatic drugs (DMARDs) at follow-up had higher OPG/RANKL ratio compared with patients who did not receive this medication. Conclusions The data supports that levels of OPG are lower in patients with JIA compared to healthy children, and higher levels of RANKL is associated with more serious disease. RANKL was a significant negative predictor of lean mass in patients with JIA. The OPG/RANKL ratio was higher in patients on DMARDs or CS treatment. PMID:21134287

  15. The Role of Depressive Symptoms, Family Invalidation and Behavioral Impulsivity in the Occurrence and Repetition of Non-Suicidal Self-Injury in Chinese Adolescents: A 2-Year Follow-Up Study

    ERIC Educational Resources Information Center

    You, Jianing; Leung, Freedom

    2012-01-01

    This study used zero-inflated poisson regression analysis to examine the role of depressive symptoms, family invalidation, and behavioral impulsivity in the occurrence and repetition of non-suicidal self-injury among Chinese community adolescents over a 2-year period. Participants, 4782 high school students, were assessed twice during the…

  16. COMPARISON OF CONDUCT DISORDER AND HYPERKINETIC CONDUCT DISORDER : A RETROSPECTIVE CLINIAL STUDY FROM NORTH INDIA

    PubMed Central

    Malhotra, Savita; Aga, Vimal M.; Balraj; Gupta, Nitin

    1999-01-01

    In a retrospective descriptive study of hyperkinetic conduct disorders (HCD) and conduct disorders (CD), as per ICD-10 diagnostic criteria, their clinical and phenomenological correlates were compared; with an aim of describing their distinctive clinical profiles. 20 cases of HCD and 25 cases of CD were compared on socio-demographic variables, temperament and specified clinical variables. The two groups differed in terms of the HCD group having younger age of onset, a more gradual development of and longer duration of conduct symptoms as compared to CD children. HCD children also had temperamental deviance (in the form of inattention, distractibility), lower IQ, more perinatal complications and delayed milestones as compared to the CD group; which made significant contribution to discriminant functions between the two groups. Results point towards different pathways of development of conduct symptomatology in HCD group as compared to the CD group PMID:21455373

  17. 40 CFR 761.326 - Conducting the comparison study.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Conducting the comparison study. 761.326 Section 761.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC...-liquid PCB Remediation Waste Samples § 761.326 Conducting the comparison study. Extract or analyze...

  18. 40 CFR 761.326 - Conducting the comparison study.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Conducting the comparison study. 761.326 Section 761.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC...-liquid PCB Remediation Waste Samples § 761.326 Conducting the comparison study. Extract or analyze...

  19. 40 CFR 761.326 - Conducting the comparison study.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Conducting the comparison study. 761.326 Section 761.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC...-liquid PCB Remediation Waste Samples § 761.326 Conducting the comparison study. Extract or analyze...

  20. Maternal Attributions and Young Children's Conduct Problems: A Longitudinal Study

    ERIC Educational Resources Information Center

    Wilson, Charlotte; Gardner, Frances; Burton, Jennifer; Leung, Sarah

    2006-01-01

    The association between negative maternal attributions and child conduct problems is well established in correlational studies. However, little is known about how these variables influence each other over time. The present study examined patterns of prediction over time between maternal attributions and pre-school conduct problems. Sixty mothers…

  1. Assessment and 2-Year Institutions.

    ERIC Educational Resources Information Center

    Bradley, Jama L.; And Others

    1994-01-01

    Describes a national study of the current availability and use of commercially and institutionally developed educational assessment instruments. Indicates that two-year institutions reported less activity than four-year institutions in assessing the major fields of study but that 77% of all two-year institutions assessed basic skills. (MAB)

  2. Conducting the Salary-Equity Study: A Consultant's View.

    ERIC Educational Resources Information Center

    McLaughlin, Gerald W.; McLaughlin, Josetta S.

    2003-01-01

    A case study approach illustrates the various statistical and political issues that analysts encounter when conducting a salary-equity study for a single institution. Highlights the importance of integrating various stakeholders in the process of assessing salary equity. (EV)

  3. French multicenter phase III randomized study testing concurrent twice-a-day radiotherapy and cisplatin/5-fluorouracil chemotherapy (BiRCF) in unresectable pharyngeal carcinoma: Results at 2 years (FNCLCC-GORTEC)

    SciTech Connect

    Bensadoun, Rene-Jean . E-mail: rene-jean.bensadoun@nice.fnclcc.fr; Benezery, Karen; Dassonville, Olivier; Magne, Nicolas; Poissonnet, Gilles; Ramaioli, Alain; Lemanski, Claire; Bourdin, Sylvain; Tortochaux, Jacques; Peyrade, Frederic; Marcy, Pierre-Yves; Chamorey, Emmanuel Phar; Vallicioni, Jacques; Seng Hang; Alzieu, Claude; Gery, Bernard; Chauvel, Pierre; Schneider, Maurice; Santini, Jose; Demard, Francois; Calais, Gilles

    2006-03-15

    Background: Unresectable carcinomas of the oropharynx and hypopharynx still have a poor long-term prognosis. Following a previous phase II study, this phase III multicenter trial was conducted between November 1997 and March 2002. Methods: Nontreated, strictly unresectable cases were eligible. Twice-daily radiation: two fractions of 1.2 Gy/day, 5 days per week, with no split (D1{sup {yields}}D46). Total tumor doses: 80.4 Gy/46 day (oropharynx), 75.6 Gy/44 day (hypopharynx). Chemotherapy (arm B): Cisplatin 100 mg/m{sup 2} (D1, D22, D43); 5FU, continuous infusion (D1{sup {yields}}D5), 750 mg/m{sup 2}/day cycle 1; 430 mg/m{sup 2}/day cycles 2 and 3. Results: A total of 163 evaluable patients. Grade 3-4 acute mucositis 82.6% arm B/69.5% arm A (NS); Grade 3-4 neutropenia 33.3% arm B/2.4% arm A (p < 0.05). Enteral nutrition through gastrostomy tube was more frequent in arm B before treatment and at 6 months (p < 0.01). At 24 months, overall survival (OS), disease-free survival (DFS), and specific survival (SS) were significantly better in arm B. OS: 37.8% arm B vs. 20.1% arm A (p = 0.038); DFS: 48.2% vs. 25.2% (p = 0.002); SS: 44.5% vs. 30.2% (p 0.021). No significant difference between the two arms in the amount of side effects at 1 and 2 years. Conclusion: For these unresectable cases, chemoradiation provides better outcome than radiation alone, even with an 'aggressive' dose-intensity radiotherapy schedule.

  4. Your Child's Development: 2 Years (24 Months)

    MedlinePlus

    ... 1- to 2-Year-Old Your Child’s Development: 2 Years (24 Months) KidsHealth > For Parents > Your Child’s Development: 2 Years (24 Months) Print A A A en español El desarrollo de su hijo: 2 años (24 meses) Tired of changing diapers? When ...

  5. A Simulation Study of Electrical Fiber Composite Conductivity

    NASA Astrophysics Data System (ADS)

    Mezdour, D.; Sahli, S.

    2008-11-01

    Percolation concept has been used in this study to estimate the amount of conductive fibers embedded in polymeric matrix, necessary to establish conduction in this kind of composites. The resistance of composite materials is calculated by simulating composite samples with different size, containing conductive fibers with various lengths Calculation is based on detecting conductive pathways through the insulating matrix, these pathways are assumed to be resistances in parallel. Electrical resistance curves showed a percolative behavior of the samples versus volume fraction of filler. Lower conduction thresholds are obtained for fiber aspect ratio of 20 and sample size of 100. The electrical resistivity and the conduction thresholds of the carbon fiber reinforced polycarbonate composites have been characterized. Simulation results are in good agreement with an experimental result found in the literature.

  6. Predictors (0-10 Months) of Psychopathology at Age 1 1/2 Years--A General Population Study in the Copenhagen Child Cohort CCC 2000

    ERIC Educational Resources Information Center

    Skovgaard, A. M.; Olsen, E. M.; Christiansen, E.; Houmann, T.; Landorph, S. L.; Jorgensen, T.

    2008-01-01

    Background: Epidemiological studies of mental health problems in the first years of life are few. This study aims to investigate infancy predictors of psychopathology in the second year of life. Methods: A random general population sample of 210 children from the Copenhagen Child Birth Cohort CCC 2000 was investigated by data from National Danish…

  7. Working Memory Arrest in Children with High-Functioning Autism Compared to Children with Attention-Deficit/Hyperactivity Disorder: Results from a 2-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Andersen, Per N.; Skogli, Erik W.; Hovik, Kjell T.; Geurts, Hilde; Egeland, Jens; Øie, Merete

    2015-01-01

    The aim of this study was to analyse the development of verbal working memory in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder and typically developing children. A total of 34 children with high-functioning autism, 72 children with attention-deficit/hyperactivity disorder and 45 typically…

  8. [Growth of breastfed and bottle-fed infants up to 2 years of age: CLACYD (Lactation, Alimentation, Growth and Development) study 1993-1995].

    PubMed

    Agrelo, F; Lobo, B; Chesta, M; Berra, S; Sabulsky, J

    1999-07-01

    Studies done in various countries show important differences in the growth of breastfed and bottle-fed children. In addition, it has been found that breast-fed children grow more slowly beginning at the age of 2 or 3 months in comparison with the reference pattern of the U.S. National Center for Health Statistics (NCHS) and the World Health Organization (WHO). These results cast doubt on whether maximum growth is the same as optimal growth. The objective of this study was to compare the growth in weight and length, from birth to 24 months, for a group of children who were breast-fed with that of a group who were bottle-fed. The study was also intended to describe the growth of the breastfed group in relation to the NCHS/WHO norms and a WHO "12-month breast-fed pooled data set." For this research, data were analyzed from the "Cordoba: lactation, feeding, growth, and development" study (or CLACYD study, for its Spanish-language acronym). That study looked at a representative cohort, stratified by social class, of children born in 1993 in the city of Cordoba, Argentina. The researchers analyzed anthropometric data on 74 children who were breast-fed during the first year of life and on 108 bottle-fed children. The data had been recorded, using standardized techniques, at birth and at 6, 12, and 24 months of age. Both groups were homogenous with respect to the age and schooling of the parents, social stratum, birth order, maternal height, and child's weight and length at birth. The living conditions (housing construction and availability of water and sewer services) were better among the group that was bottle-fed (P = 0.04). The breast-fed children had a lower weight and a shorter length at 6, 12, and 24 months than did the bottle-fed children. The breast-fed children also showed a slowing in growth with respect to the NCHS/WHO guidelines beginning in the second semester. This indicates that the NCHS/WHO norms are not totally adequate for evaluating the growth of breast

  9. Variability of NT-proBNP and Its Relationship with Inflammatory Status in Patients with Stable Essential Hypertension: A 2-Year Follow-Up Study

    PubMed Central

    Roselló-Lletí, Esther; Calabuig, Jose R.; Morillas, Pedro; Cortés, Raquel; Martínez-Dolz, Luis; Almenar, Luis; González-Juanatey, Jose R.; Lauwers, Catheline; Salvador, Antonio; Portolés, Manuel; Bertomeu, Vicente; Rivera, Miguel

    2012-01-01

    Background The variability of NT-proBNP levels has been studied in heart failure, yet no data exist on these changes over time in hypertensive patients. Furthermore, studies on the relationship between natriuretic peptides and inflammatory status are limited. Methodology/Principal Findings 220 clinically and functionally asymptomatic stable patients (age 59±13, 120 male) out of 252 patients with essential hypertension were followed up, and NT-proBNP was measured at baseline, 12 and 24 months. No differences in NT-proBNP were found with respect to the basal stage in the hypertrophic group, but significant changes were found in non-hypertrophic subjects. The reproducibility of NT-proBNP measurements was better in patients with hypertrophy than in the non-hypertrophic group for the three intervals (stage I-basal; stage II-stage I; stage II-basal) with a reference change value of 34%, 35% and 41%, respectively, in the hypertrophic group. A more elevated coefficient of correlation was obtained in the hypertrophic group than in patients without hypertrophy: basal versus stage I (r = 0.79, p<0.0001 and r = 0.59, p<0.0001) and stage I versus stage II (r = 0.86, p<0.0001 and r = 0.56, p<0.0001). Finally, levels of NT-proBNP significantly correlated with sTNF-R1 (p<0.0001) and IL-6 (p<0.01) during follow-up. A multivariate linear regression analysis showed that sTNF-R1 is an independent factor of NT-proBNP. Conclusions/Significance This work shows that there is good stability in NT-proBNP levels in a follow-up study of asymptomatic patients with stable hypertension and left ventricular hypertrophy. As a consequence, assessment of NT-proBNP concentrations may be a useful tool for monitoring the follow-up of hypertensive patients with hypertrophy. Measured variations in peptide levels, exceeding 35% in a 12-month follow-up and 41% in a 24-month follow-up, may indicate an increase in cardiovascular risk, and therefore implies adjustment in the medical treatment

  10. Antimicrobial susceptibility profile, treatment outcome and serotype distribution of clinical isolates of Salmonella enterica subspecies enterica: a 2-year study from Kerala, South India

    PubMed Central

    Harichandran, Deepa; Dinesh, Kavitha Radhakrishnan

    2017-01-01

    Background/purpose Typhoid and paratyphoid fever continue to be important causes of illness and death in parts of Asia, being associated with poor sanitation and consumption of unsafe food and water. Antimicrobial resistance has emerged to traditional first-line drugs, namely, the fluoroquinolones, as well as to third-generation cephalosporins, posing challenges to treatment. Azithromycin has proven to be an effective alternative for treatment of uncomplicated typhoid fever. The purpose of this study was to determine the antimicrobial susceptibility, clinical outcome and serotype distribution pattern of clinical isolates belonging to Salmonella enterica subspecies enterica. Methodology All clinical isolates of S. enterica obtained from blood, sterile body fluids, as well as stool and urine samples at Amrita Institute of Medical Sciences and Research Centre, Kerala, India, between August 2011 and July 2013 were included in the study and processed based on standard microbiology protocols. Results A total of 118 isolates of Salmonella were obtained during the study period. Out of these, 79 were of S. Typhi (66.95%), followed by isolates of S. Paratyphi A (22; 18.64%) and S. Typhimurium 12 (10.17%). Five isolates could not be identified further. There was 100% susceptibility to ceftriaxone in all S. enterica subspecies. Ciprofloxacin susceptibility was 32.91% for S. Typhi and 40.90% for S. Paratyphi A as determined by the disk diffusion method. The susceptibility profile of S. Typhi isolates to different antimicrobials was as follows: chloramphenicol (94.93%), ampicillin (77.21%), cotrimoxazole (75.94%) and azithromycin (78.48%). For S. Typhi, the minimum inhibitory concentration (MIC) of ciprofloxacin required to inhibit the growth of 50% of organisms was 0.5 μg/mL (intermediate) and MIC required to inhibit the growth of 90% of organisms was 1 μg/mL (resistant). S. Typhimurium was 100% susceptible to cotrimoxazole, ampicillin, ceftriaxone, chloramphenicol, ofloxacin

  11. Detection of viruses in weekly stool specimens collected during the first 2 years of life: A pilot study of five healthy Australian infants in the rotavirus vaccine era.

    PubMed

    Ye, Suifang; Whiley, David M; Ware, Robert S; Sloots, Theo P; Kirkwood, Carl D; Grimwood, Keith; Lambert, Stephen B

    2017-05-01

    Several viruses are associated with gastroenteritis in infants. This pilot study, nested within a larger community-based project of early childhood infections, collected daily symptom data and 511 weekly stool samples from five healthy, fully vaccinated, term infants from birth until their second birthday. Real-time PCR assays were used to detect six enteric viruses. Frequent, silent shedding of one or more of the six viruses was observed, particularly involving adenovirus where shedding could be for up to 3 months without gastrointestinal symptoms. These pilot data demonstrate that a positive PCR result for enteric viruses may not always indicate the cause of childhood gastroenteritis. J. Med. Virol. 89:917-921, 2017. © 2016 Wiley Periodicals, Inc.

  12. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    NASA Astrophysics Data System (ADS)

    Nagendra, K.; Babu, G. Satish; Reddy, C. Narayana; Gowda, Veeranna

    2011-07-01

    Glasses in the system xLi2SO4-20Li2O-(80-x) [80P2O5-20V2O5] (5⩾x⩾20 mol%) has been prepared by melt quenching method. Dc and ac conductivity has been studied over a wide range of frequency (10 Hz to 10 MHz) and temperature (298 K-523 K). The dc conductivity found to increase with increase of Li2SO4 concentration. The ac conductivities have been fitted to the Almond-West type single power law equation σ(ω) = σ(0)+Aωs where `s' is the power law exponent. The ac conductivity found to increase with increase of Li2SO4 concentration. An attempt is made to elucidate the enhancement of lithium ion conduction in phosphor-vanadate glasses by considering the expansion of network structure.

  13. The Role of Human Coronaviruses in Children Hospitalized for Acute Bronchiolitis, Acute Gastroenteritis, and Febrile Seizures: A 2-Year Prospective Study

    PubMed Central

    Jevšnik, Monika; Steyer, Andrej; Pokorn, Marko; Mrvič, Tatjana; Grosek, Štefan; Strle, Franc; Lusa, Lara; Petrovec, Miroslav

    2016-01-01

    Human coronaviruses (HCoVs) are associated with a variety of clinical presentations in children, but their role in disease remains uncertain. The objective of our prospective study was to investigate HCoVs associations with various clinical presentations in hospitalized children up to 6 years of age. Children hospitalized with acute bronchiolitis (AB), acute gastroenteritis (AGE), or febrile seizures (FS), and children admitted for elective surgical procedures (healthy controls) were included in the study. In patients with AB, AGE, and FS, a nasopharyngeal (NP) swab and blood sample were obtained upon admission and the follow-up visit 14 days later, whereas in children with AGE a stool sample was also acquired upon admission; in healthy controls a NP swab and stool sample were taken upon admission. Amplification of polymerase 1b gene was used to detect HCoVs in the specimens. HCoVs-positive specimens were also examined for the presence of several other viruses. HCoVs were most often detected in children with FS (19/192, 9.9%, 95% CI: 6–15%), followed by children with AGE (19/218, 8.7%, 95% CI: 5.3–13.3%) and AB (20/308, 6.5%, 95% CI: 4.0–9.8%). The presence of other viruses was a common finding, most frequent in the group of children with AB (19/20, 95%, 95% CI: 75.1–99.8%), followed by FS (10/19, 52.6%, 95% CI: 28.9–75.6%) and AGE (7/19, 36.8%, 95% CI: 16.3–61.6%). In healthy control children HCoVs were detected in 3/156 (1.9%, 95% CI: 0.4–5.5%) NP swabs and 1/150 (0.7%, 95% CI: 0.02–3.3%) stool samples. It seems that an etiological role of HCoVs is most likely in children with FS, considering that they had a higher proportion of positive HCoVs results than patients with AB and those with AGE, and had the highest viral load; however, the co-detection of other viruses was 52.6%. Trial Registration: ClinicalTrials.gov NCT00987519 PMID:27171141

  14. Decreased use of glucocorticoids in biological-experienced patients with rheumatoid arthritis who initiated intravenous abatacept: results from the 2-year ACTION study

    PubMed Central

    Alten, Rieke; Nüßlein, Hubert; Galeazzi, Mauro; Lorenz, Hanns-Martin; Nurmohamed, Michael T; Bensen, William G; Burmester, Gerd R; Peter, Hans-Hartmut; Pavelka, Karel; Chartier, Mélanie; Poncet, Coralie; Rauch, Christiane; Elbez, Yedid; Le Bars, Manuela

    2016-01-01

    Introduction Prolonged glucocorticoid use may increase the risk of adverse safety outcomes, including cardiovascular events. The European League Against Rheumatism and the Canadian Rheumatology Association advise tapering glucocorticoid dose as rapidly as clinically feasible. There is a paucity of published data on RA that adequately describe concomitant treatment patterns. Methods ACTION (AbataCepT In rOutiNe clinical practice) is a non-interventional cohort study of patients from Europe and Canada that investigated the long-term retention of intravenous abatacept in clinical practice. We assessed concomitant glucocorticoids in patients with established RA who had participated in ACTION and received ≥1 biological agent prior to abatacept initiation. Results The analysis included 1009 patients. Glucocorticoids were prescribed at abatacept initiation in 734 (72.7%) patients at a median 7.5 mg/day dose (n=692). Of the patients who remained on abatacept at 24 months, 40.7% were able to decrease their dose of glucocorticoids, including 26.9% who decreased their dose from >5 mg/day to ≤5 mg/day. Conclusion Reduction and/or cessation of glucocorticoid therapy is possible with intravenous abatacept in clinical practice. PMID:26925253

  15. The ADVANCE Code of Conduct for collaborative vaccine studies.

    PubMed

    Kurz, Xavier; Bauchau, Vincent; Mahy, Patrick; Glismann, Steffen; van der Aa, Lieke Maria; Simondon, François

    2017-04-04

    Lessons learnt from the 2009 (H1N1) flu pandemic highlighted factors limiting the capacity to collect European data on vaccine exposure, safety and effectiveness, including lack of rapid access to available data sources or expertise, difficulties to establish efficient interactions between multiple parties, lack of confidence between private and public sectors, concerns about possible or actual conflicts of interest (or perceptions thereof) and inadequate funding mechanisms. The Innovative Medicines Initiative's Accelerated Development of VAccine benefit-risk Collaboration in Europe (ADVANCE) consortium was established to create an efficient and sustainable infrastructure for rapid and integrated monitoring of post-approval benefit-risk of vaccines, including a code of conduct and governance principles for collaborative studies. The development of the code of conduct was guided by three core and common values (best science, strengthening public health, transparency) and a review of existing guidance and relevant published articles. The ADVANCE Code of Conduct includes 45 recommendations in 10 topics (Scientific integrity, Scientific independence, Transparency, Conflicts of interest, Study protocol, Study report, Publication, Subject privacy, Sharing of study data, Research contract). Each topic includes a definition, a set of recommendations and a list of additional reading. The concept of the study team is introduced as a key component of the ADVANCE Code of Conduct with a core set of roles and responsibilities. It is hoped that adoption of the ADVANCE Code of Conduct by all partners involved in a study will facilitate and speed-up its initiation, design, conduct and reporting. Adoption of the ADVANCE Code of Conduct should be stated in the study protocol, study report and publications and journal editors are encouraged to use it as an indication that good principles of public health, science and transparency were followed throughout the study.

  16. The MCT-ketogenic diet as a treatment option in refractory childhood epilepsy: A prospective study with 2-year follow-up.

    PubMed

    Lambrechts, Danielle A J E; de Kinderen, Reina J A; Vles, Hans S H; de Louw, Anton J; Aldenkamp, Albert P; Majoie, Marian J M

    2015-10-01

    The present study assessed the long-term (i.e., 24months) efficacy of the ketogenic diet (KD) as an add-on therapy in children with refractory epilepsy, with focus on seizure frequency, seizure severity, and tolerability. Most patients were treated with the MCT-diet. At one and two years, 33% and 23%, respectively, of the 48 included patients were still on the KD. After three months, one year, and two years of treatment, 16.7% of the patients were responders. The highest responder rate (i.e., 22.9%) was seen at six and nine months of treatment. Of the fifteen patients with seizure clusters during baseline, 60% were responders after three months when looking at cluster reduction and most of them were not responders for the total seizure frequency. From three months of treatment onwards, most of the patients had a relevant decrease in seizure severity which was mainly related to the most severe seizure type. Gastrointestinal dysfunction was often reported, especially in the first six weeks of treatment. Growth deceleration was present in 30% of the patients, and weight reduction in 15%. Improved arousal was mentioned in 30% of patients. No patients developed ECG abnormalities or kidney stones. Increase in lipid profile was rare. The KD is an effective therapy for children with therapy-resistant epilepsy. Effectiveness is reflected in the reduction of seizure frequency as well as in the reduction of seizure severity. After 6months of treatment, it is obvious which patients are responders and tolerate the treatment well. Most of these patients will continue to benefit from the KD for a longer time. Long-term use of the diet was well tolerated.

  17. Change in Care Dependency and Nursing Care Problems in Nursing Home Residents with and without Dementia: A 2-Year Panel Study.

    PubMed

    Schüssler, Sandra; Lohrmann, Christa

    2015-01-01

    Over time, chronic conditions like dementia can lead to care dependency and nursing care problems, often necessitating nursing home admission. This panel study (2012-2014) aims to explore changes in care dependency and nursing care problems (incontinence, malnutrition, decubitus, falls and restraints) in residents with and without dementia over time. In total, nine Austrian nursing homes participated, including 258 residents (178 with, 80 without dementia) who completed all five measurements. Data were collected with the International Prevalence Measurement of Care Problems questionnaire, the Care Dependency Scale and the Mini-Mental State Examination-2. Repeated measures ANOVA and crosstabs were used to analyse changes. The results showed that care dependency in dementia residents increased significantly for all 15 items of the Care Dependency Scale, with the highest increase being residents' day-/night pattern, contact with others, sense of rules/values and communication. In contrast, care dependency in residents without dementia increased for four of the 15 items, with the highest increase being for continence, followed by getting (un)dressed. With respect to the assessed nursing care problems, residents with dementia and those without only differed significantly in terms of an increase in urinary- (12.3% vs. 14.2%), fecal- (17.4% vs. 10%), and double incontinence (16.7% vs. 11.9%). The results indicated that residents with dementia experienced increased care dependency in different areas than residents without dementia. Furthermore, residents with dementia experienced a lower increase in urinary incontinence but a higher increase in fecal- and double incontinence. These results help professionals to identify areas for improvement in dementia care.

  18. The relationships of change in work climate with changes in burnout and depression: a 2-year longitudinal study of Chinese mental health care workers.

    PubMed

    Fong, Ted C T; Ho, Rainbow T H; Au-Yeung, Friendly S W; Sing, C Y; Law, K Y; Lee, L F; Ng, S M

    2015-09-01

    Mental health care workers face heavy emotional demand and are prone to work burnout. Work burnout has been associated with poor mental health and work climate, which refers to individual perceptions about work setting. The purpose of this study was to examine whether intra-individual changes in work climate were associated with intra-individual changes in burnout and depression over two years. The present sample included Chinese mental health care workers (N = 312; mean age = 38.6, SD = 9.9) working in a psychosocial rehabilitation institution. The participants completed questionnaires on work climate, work burnout and depression at seven time points across two years. Parallel process latent growth modeling was used to analyze the associations of change between work climate and burnout and depression. Work climate displayed a logarithmic decreasing trend while burnout and depression displayed logarithmic increasing trends over two years. Baseline levels of work climate were negatively and moderately associated with baseline levels of burnout and depression (r = -.44 to -.60, p < .01). Changes in work climate were negatively and moderately associated with change in burnout (r = -.43, p < .01) and change in depression (r = -.31, p < .05). Change in burnout was positively and strongly associated (r = .58, p < .01) with change in depression. The current results support temporal relationships among changes in work climate, burnout and depression across time. Practical implications for future preventive work in burnout interventions were discussed within this population.

  19. Clinical instructors' perception of a faculty development programme promoting postgraduate year-1 (PGY1) residents' ACGME six core competencies: a 2-year study.

    PubMed

    Lee, Fa-Yauh; Yang, Ying-Ying; Hsu, Hui-Chi; Chuang, Chiao-Lin; Lee, Wei-Shin; Chang, Ching-Chih; Huang, Chia-Chang; Chen, Jaw-Wen; Cheng, Hao-Min; Jap, Tjin-Shing

    2011-01-01

    Objective The six core competencies designated by Accreditation Council for Graduate Medical Education (ACGME) are essential for establishing a patient centre holistic medical system. The authors developed a faculty programme to promote the postgraduate year 1 (PGY(1)) resident, ACGME six core competencies. The study aims to assess the clinical instructors' perception, attitudes and subjective impression towards the various sessions of the 'faculty development programme for teaching ACGME competencies.' Methods During 2009 and 2010, 134 clinical instructors participated in the programme to establish their ability to teach and assess PGY(1) residents about ACGME competencies. Results The participants in the faculty development programme reported that the skills most often used while teaching were learnt during circuit and itinerant bedside, physical examination teaching, mini-clinical evaluation exercise (mini-CEX) evaluation demonstration, training workshop and videotapes of 'how to teach ACGME competencies.' Participants reported that circuit bedside teaching and mini-CEX evaluation demonstrations helped them in the interpersonal and communication skills domain, and that the itinerant teaching demonstrations helped them in the professionalism domain, while physical examination teaching and mini-CEX evaluation demonstrations helped them in the patients' care domain. Both the training workshop and videotape session increase familiarity with teaching and assessing skills. Participants who applied the skills learnt from the faculty development programme the most in their teaching and assessment came from internal medicine departments, were young attending physician and had experience as PGY(1) clinical instructors. Conclusions According to the clinical instructors' response, our faculty development programme effectively increased their familiarity with various teaching and assessment skills needed to teach PGY(1) residents and ACGME competencies, and these clinical

  20. Study of AC electrical conduction mechanisms in an epoxy polymer

    NASA Astrophysics Data System (ADS)

    Jilani, Wissal; Mzabi, Nissaf; Gallot-Lavallée, Olivier; Fourati, Najla; Zerrouki, Chouki; Zerrouki, Rachida; Guermazi, Hajer

    2015-11-01

    The AC conductivity of an epoxy resin was investigated in the frequency range 10^{-1} - 106 Hz at temperatures ranging from -100 to 120 °C. The frequency dependence of σ_{ac} was described by the law: σ_{ac}=ω \\varepsilon0\\varepsilon^''_{HN}+Aωs. The study of temperature variation of the exponent (s) reveals two conduction models: the AC conduction dependence upon temperature is governed by the small polaron tunneling mechanism (SPTM) at low temperature (-100 -60 °C) and the correlated barrier hopping (CHB) model at high temperature (80-120 °C).

  1. Thermal conductivity of penta-graphene from molecular dynamics study.

    PubMed

    Xu, Wen; Zhang, Gang; Li, Baowen

    2015-10-21

    Using classical equilibrium molecular dynamics simulations and applying the original Tersoff interatomic potential, we study the thermal transport property of the latest two dimensional carbon allotrope, penta-graphene. It is predicted that its room-temperature thermal conductivity is about 167 W/mK, which is much lower than that of graphene. With normal mode decomposition, the accumulated thermal conductivity with respect to phonon frequency and mean free path is analyzed. It is found that the acoustic phonons make a contribution of about 90% to the thermal conductivity, and phonons with mean free paths larger than 100 nm make a contribution over 50%. We demonstrate that the remarkably lower thermal conductivity of penta-graphene compared with graphene results from the lower phonon group velocities and fewer collective phonon excitations. Our study highlights the importance of structure-property relationship and provides better understanding of thermal transport property and valuable insight into thermal management of penta-graphene.

  2. Electrical studies on silver based fast ion conducting glassy materials

    SciTech Connect

    Rao, B. Appa Kumar, E. Ramesh Kumari, K. Rajani Bhikshamaiah, G.

    2014-04-24

    Among all the available fast ion conductors, silver based glasses exhibit high conductivity. Further, glasses containing silver iodide enhances fast ion conducting behavior at room temperature. Glasses of various compositions of silver based fast ion conductors in the AgI−Ag{sub 2}O−[(1−x)B{sub 2}O{sub 3}−xTeO{sub 2}] (x=0 to1 mol% in steps of 0.2) glassy system have been prepared by melt quenching method. The glassy nature of the compounds has been confirmed by X-ray diffraction. The electrical conductivity (AC) measurements have been carried out in the frequency range of 1 KHz–3MHz by Impedance Analyzer in the temperature range 303–423K. The DC conductivity measurements were also carried out in the temperature range 300–523K. From both AC and DC conductivity studies, it is found that the conductivity increases and activation energy decreases with increasing the concentration of TeO{sub 2} as well as with temperature. The conductivity of the present glass system is found to be of the order of 10{sup −2} S/cm at room temperature. The ionic transport number of these glasses is found to be 0.999 indicating that these glasses can be used as electrolyte in batteries.

  3. Establishing improved normal values for nerve conduction studies.

    PubMed

    Buschbacher, Ralph M

    2006-01-01

    Nerve conduction studies are commonly performed to diagnose injuries of the peripheral nerves. In the past, normal ranges have been derived on relatively small samples of normal subjects. These ranges were often suboptimal for clinical use. Therefore, this series of articles was created to establish an improved database of normative values. It highlights the key contributions of a number of authors. In this foreword, the contributions of the various authors to the special issue on the development of an improved database for nerve conduction studies are described. The authors are introduced, including their training, gifts, and which articles they were involved in writing. In addition, there is a brief review of each of the articles in this special supplement. The fundamentals of ulnar motor nerve conduction to the first dorsal interosseous muscle are described, as is the contribution of Nate Prahlow, MD. In addition, the median motor nerve conduction to the pronator teres muscle and flexor carpi radialis muscle is highlighted including the contributions of Brian Foley, MD. The radial sensory nerve and dorsal ulnar cutaneous sensory nerve studies are described, as well as the contributions of Van Evanoff, Jr., MD, in creating this research. Median motor conduction to the lumbrical muscles and ulnar motor conduction to the palmar interosseous muscles are described, again highlighting the contributions of Dr. Foley. In addition, medial and lateral antebrachial cutaneous nerve studies are described, along with the contributions of Dr. Nathan Prahlow. Median and ulnar sensory conduction studies recording from the fourth digit, as well as median and radial sensory conduction to the first digit, are described, as are the contributions of James Lohman, MD, and Andrew Berkson, DO. The side-to-side differences in median and ulnar sensory conduction studies and the importance of performing such studies are described, as are the contributions in this research of Dr. Nathan

  4. Methodology for the Conduct of a Seismic Risk Mitigation Study.

    DTIC Science & Technology

    1985-06-01

    33 3. The Base..................34 4. The Study Group ................34 III. DETERMINATION OF MISSION ESSENTIAL FACILITIES .. 36 A...97 APPENDIX C: NAVY EARTHQUAKE ADVISORY GROUP MODELS . 115 A. SEISMIC RISK MITIGATION MODEL...........115 B. ILLUSTRATIVE EXAMPLE OF THE BASIC MODEL...study group formed to conduct the Seismic Risk Mitigation Study. The first phase of the study is determining the missions of the base and determining

  5. Paraphasias in Multilingual Conduction Aphasia: A Single Case Study

    ERIC Educational Resources Information Center

    Hegde, Medha; Bhat, Sapna

    2007-01-01

    Conduction aphasia is a type of fluent aphasia, which is caused due to the damage to the supramarginal gyrus and arcuate fasciculus resulting in repetition disturbance. It has been speculated that linguistic system in bilingual aphasics can breakdown in different ways across languages. There is a lack of detailed linguistic studies in specific…

  6. The medial antebrachial cutaneous nerve: antidromic and orthodromic conduction studies.

    PubMed

    Seror, Paul

    2002-09-01

    Medial antebrachial cutaneous nerve (MABCN) conduction studies were performed antidromically and orthodromically in 70 control subjects to determine normal values and define the lower limits of normality. The mean sensory action potential (SAP) amplitudes were 17.7 and 17.5 microV and the sensory conduction velocities were 60 and 61 m/s, respectively, with the antidromic and orthodromic techniques. With both techniques, no SAP amplitude was lower than 6 microV. The lower limits of normal of the interside amplitude ratio were 1.66 when both techniques were used and 2.0 when only one was used.

  7. Heat conduction in multifunctional nanotrusses studied using Boltzmann transport equation

    NASA Astrophysics Data System (ADS)

    Dou, Nicholas G.; Minnich, Austin J.

    2016-01-01

    Materials that possess low density, low thermal conductivity, and high stiffness are desirable for engineering applications, but most materials cannot realize these properties simultaneously due to the coupling between them. Nanotrusses, which consist of hollow nanoscale beams architected into a periodic truss structure, can potentially break these couplings due to their lattice architecture and nanoscale features. In this work, we study heat conduction in the exact nanotruss geometry by solving the frequency-dependent Boltzmann transport equation using a variance-reduced Monte Carlo algorithm. We show that their thermal conductivity can be described with only two parameters, solid fraction and wall thickness. Our simulations predict that nanotrusses can realize unique combinations of mechanical and thermal properties that are challenging to achieve in typical materials.

  8. Heat conduction in multifunctional nanotrusses studied using Boltzmann transport equation

    SciTech Connect

    Dou, Nicholas G.; Minnich, Austin J.

    2016-01-04

    Materials that possess low density, low thermal conductivity, and high stiffness are desirable for engineering applications, but most materials cannot realize these properties simultaneously due to the coupling between them. Nanotrusses, which consist of hollow nanoscale beams architected into a periodic truss structure, can potentially break these couplings due to their lattice architecture and nanoscale features. In this work, we study heat conduction in the exact nanotruss geometry by solving the frequency-dependent Boltzmann transport equation using a variance-reduced Monte Carlo algorithm. We show that their thermal conductivity can be described with only two parameters, solid fraction and wall thickness. Our simulations predict that nanotrusses can realize unique combinations of mechanical and thermal properties that are challenging to achieve in typical materials.

  9. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    SciTech Connect

    Nagendra, K.; Babu, G. Satish; Gowda, Veeranna; Reddy, C. Narayana

    2011-07-15

    Glasses in the system xLi{sub 2}SO{sub 4}-20Li{sub 2}O-(80-x) [80P{sub 2}O{sub 5}-20V{sub 2}O{sub 5}](5{>=}x{>=}20 mol%) has been prepared by melt quenching method. Dc and ac conductivity has been studied over a wide range of frequency (10 Hz to 10 MHz) and temperature (298 K-523 K). The dc conductivity found to increase with increase of Li{sub 2}SO{sub 4} concentration. The ac conductivities have been fitted to the Almond-West type single power law equation {sigma}({omega}) = {sigma}(0)+A{omega}{sup s} where 's' is the power law exponent. The ac conductivity found to increase with increase of Li{sub 2}SO{sub 4} concentration. An attempt is made to elucidate the enhancement of lithium ion conduction in phosphor-vanadate glasses by considering the expansion of network structure.

  10. Time resolved strain dependent morphological study of electrically conducting nanocomposites

    NASA Astrophysics Data System (ADS)

    Khan, Imran; Mitchell, Geoffrey; Mateus, Artur; Kamma-Lorger, Christina S.

    2015-10-01

    An efficient and reliable method is introduced to understand the network behaviour of nano-fillers in a polymeric matrix under uniaxial strain coupled with small angle x-ray scattering measurements. The nanoparticles (carbon nanotubes) are conductive and the particles form a percolating network that becomes apparent source of electrical conduction and consequently the samples behave as a bulk conductor. Polyurethane based nanocomposites containing 2% w/w multiwall carbon nanotubes are studied. The electrical conductivity of the nanocomposite was (3.28×10-5s/m).The sample was able to be extended to an extension ratio of 1.7 before fracture. A slight variation in the electrical conductivity is observed under uniaxial strain which we attribute to the disturbance of conductive pathways. Further, this work is coupled with in- situ time resolved small angle x-ray scattering measurements using a synchrotron beam line to enable its measurements to be made during the deformation cycle. We use a multiscale structure to model the small angle x-ray data. The results of the analysis are interpreted as the presence of aggregates which would also go some way towards understanding why there is no alignment of the carbon nanotubes.

  11. Temporal study of wake formation behind a conducting body

    NASA Technical Reports Server (NTRS)

    Meassick, S.; Chan, C.; Qian, Y.; Sroda, T.; Azar, T.

    1991-01-01

    The temporal evolution of the wake of a conducting body is studied experimentally in a pulsed plasma device. Three-dimensional measurements of the plasma potential, density, particle energy distribution, and ion currents are measured throughout the near- and mid-wake regions during the wake formation. It is found that the potential behind the conducting body is initially negative. This negative potential is caused by the higher mobility of the electrons, allowing them to flow into the ion free wake region. The negative potential in the wake region induces an electric field that pulls ions into the region behind the conducting body. However, the dominant factor in determining the length of the near wake is the thermal energy spread of the ions. At later times, as the sheath forms around the conducting body, ions are deflected by the potential gradient in the sheath region. This deflection, in addition to the thermal energy spread of the ions, determines the length of the near wake.

  12. Studies on conducting polymer and conducting polymerinorganic composite electrodes prepared via a new cathodic polymerization method

    NASA Astrophysics Data System (ADS)

    Singh, Nikhilendra

    A novel approach for the electrodeposition of conducting polymers and conducting polymer-inorganic composite materials is presented. The approach shows that conducting polymers, such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) can be electrodeposited by the application of a cathodic bias that generates an oxidizing agent, NO+, via the in-situ reduction of nitrate anions. This new cathodic polymerization method allows for the deposition of PPy and PEDOT as three dimensional, porous films composed of spherical polymer particles. The method is also suitable for the co-deposition of inorganic species producing conducting polymer-inorganic composite electrodes. Such composites are used as high surface area electrodes in Li-ion batteries, electrochemical hydrogen evolution and in the development of various other conducting polymer-inorganic composite electrodes. New Sn-PPy and Sb-PPy composite electrodes where Sn and Sb nanoparticles are well dispersed among the PPy framework are reported. These structures allow for decreased stress during expansion and contraction of the active material (Sn, Sb) during the alloying and de-alloying processes of a Li-ion battery anode, significantly alleviating the loss of active material due to pulverization processes. The new electrochemical synthesis mechanism allows for the fabrication of Sn-PPy and Sb-PPy composite electrodes directly from a conducting substrate and eliminates the use of binding materials and conducting carbon used in modern battery anodes, which significantly simplifies their fabrication procedures. Platinum (Pt) has long been identified as the most efficient catalyst for electrochemical water splitting, while nickel (Ni) is a cheaper, though less efficient alternative to Pt. A new morphology of PPy attained via the aforementioned cathodic deposition method allows for the use of minimal quantities of Pt and Ni dispersed over a very high surface area PPy substrate. These composite electrodes

  13. The role of depressive symptoms, family invalidation and behavioral impulsivity in the occurrence and repetition of non-suicidal self-injury in Chinese adolescents: a 2-year follow-up study.

    PubMed

    You, Jianing; Leung, Freedom

    2012-04-01

    This study used zero-inflated poisson regression analysis to examine the role of depressive symptoms, family invalidation, and behavioral impulsivity in the occurrence and repetition of non-suicidal self-injury among Chinese community adolescents over a 2-year period. Participants, 4782 high school students, were assessed twice during the follow-up period. Results indicate that while Year 1 depressive symptoms and family invalidation were significantly associated with the occurrence of Year 2 NSSI, Year 1 behavioral impulsivity contributed to both the occurrence and repetition of Year 2 NSSI. Findings of this study suggest that adolescents who display multiple impulsive behaviors may be at particular risk for engaging in repetitive NSSI. Clinical implications of these findings and future research directions were discussed.

  14. Ultrasound-Guided Lateral Femoral Cutaneous Nerve Conduction Study

    PubMed Central

    Park, Bum Jun; Joeng, Eui Soo; Choi, Jun Kyu; Kang, Seok; Yoon, Joon Shik

    2015-01-01

    Objective To verify the utility of the lateral femoral cutaneous nerve (LFCN) ultrasound-guided conduction technique compared to that of the conventional nerve conduction technique. Methods Fifty-eight legs of 29 healthy participants (18 males and 11 females; mean age, 42.7±14.9 years) were recruited. The conventional technique was performed bilaterally. The LFCN was localized by ultrasound. Cross-sectional area (CSA) of the LFCN and the distance between the anterior superior iliac spine (ASIS) and the LFCN was measured. The nerve conduction study was repeated with the corrected cathode location. Sensory nerve action potential (SNAP) amplitudes of the LFCN were recorded and compared between the ultrasound-guided and conventional techniques. Results Mean body mass index of the participants was 23.7±3.5 kg/m2, CSA was 4.2±1.9 mm2, and the distance between the ASIS and LFCN was 5.6±1.7 mm. The mean amplitude values were 6.07±0.52 µV and 6.66±0.54 µV using the conventional and ultrasound-guided techniques, respectively. The SNAP amplitude of the LFCN using the ultrasound-guided technique was significantly larger than that recorded using the conventional technique. Conclusion Correcting the stimulation position using the ultrasound-guided technique helped obtain increased SNAP amplitude. PMID:25750871

  15. Electronic conductivity studies on oxyhalide glasses containing TMO

    NASA Astrophysics Data System (ADS)

    Vijayatha, D.; Viswanatha, R.; Sujatha, B.; Narayana Reddy, C.

    2016-05-01

    Microwave-assisted synthesis is cleaner, more economical and much faster than conventional methods. The development of new routes for the synthesis of solid materials is an integral part of material science and technology. The electronic conductivity studies on xPbCl2 - 60 PbO - (40-x) V2O5 (1 ≥ x ≤ 10) glass system has been carried out over a wide range of composition and temperature (300 K to 423 K). X-ray diffraction study confirms the amorphous nature of the samples. The Scanning electron microscopic studies reveal the formation of cluster like morphology in PbCl2 containing glasses. The d.c conductivity exhibits Arrhenius behaviour and increases with V2O5 concentration. Analysis of the results is interpreted in view Austin-Mott's small polaron model of electron transport. Activation energies calculated using regression analysis exhibit composition dependent trend and the variation is explained in view of the structure of lead-vanadate glass.

  16. Conducting Simulation Studies in the R Programming Environment.

    PubMed

    Hallgren, Kevin A

    2013-10-12

    Simulation studies allow researchers to answer specific questions about data analysis, statistical power, and best-practices for obtaining accurate results in empirical research. Despite the benefits that simulation research can provide, many researchers are unfamiliar with available tools for conducting their own simulation studies. The use of simulation studies need not be restricted to researchers with advanced skills in statistics and computer programming, and such methods can be implemented by researchers with a variety of abilities and interests. The present paper provides an introduction to methods used for running simulation studies using the R statistical programming environment and is written for individuals with minimal experience running simulation studies or using R. The paper describes the rationale and benefits of using simulations and introduces R functions relevant for many simulation studies. Three examples illustrate different applications for simulation studies, including (a) the use of simulations to answer a novel question about statistical analysis, (b) the use of simulations to estimate statistical power, and (c) the use of simulations to obtain confidence intervals of parameter estimates through bootstrapping. Results and fully annotated syntax from these examples are provided.

  17. Thermal conductivity and rectification study of restructured Graphene

    NASA Astrophysics Data System (ADS)

    Arora, Anuj

    Electronics' miniaturization, has led to search for better thermal management techniques and discovery of important transport phenomenon. Thermal rectification, directionally preferential heat transport analogous to electrical diode, is one such technique, garnering tremendous interest. Its possibility has been explored through structural asymmetry, introducing a differential phonon density of states in hot and cold regions. As of now, mass and shape asymmetries have been studied, both experimentally and theoretically. However, strict requirements of material length being shorter than phonon mean free path and phonon coherence preservation at surface, makes connecting two materials with different temperature-dependent thermal conductivities, a more natural approach. To avoid resultant thermal boundary resistance and integration complexities, we achieve the affect in single material, by restructuring a region of Graphene by introducing defects. The asymmetry impedes ballistic phonon transport, modulating temperature dependence of thermal conductivity in the two regions. We perform deviational Monte Carlo simulations based on Energy-based formulation to microscopically investigate phonon transport, possibility and optimal conditions for thermal rectification. The proposed method uses phonon properties obtained from first principle, treat phonon-boundary scattering explicitly with properties drawn from Bose-Einstein Distribution.

  18. Computer-Guided Implant Surgery in Fresh Extraction Sockets and Immediate Loading of a Full Arch Restoration: A 2-Year Follow-Up Study of 14 Consecutively Treated Patients

    PubMed Central

    Daas, M.; Assaf, A.; Dada, K.; Makzoumé, J.

    2015-01-01

    Statement of Problem. Low scientific evidence is identified in the literature for combining implant placement in fresh extraction sockets with immediate function. Moreover, the few studies available on immediate implants in postextraction sites supporting immediate full-arch rehabilitation clearly lack comprehensive protocols. Purpose. The purpose of this study is to report outcomes of a comprehensive protocol using CAD-CAM technology for surgical planning and fabrication of a surgical template and to demonstrate that immediate function can be easily performed with immediate implants in postextraction sites supporting full-arch rehabilitation. Material and Methods. 14 subjects were consecutively rehabilitated (13 maxillae and 1 mandible) with 99 implants supporting full-arch fixed prostheses followed between 6 and 24 months (mean of 16 months). Outcome measures were prosthesis and implant success, biologic and prosthetic complications, pain, oedema evaluation, and radiographic marginal bone levels at surgery and then at 6, 12, 18, and 24 months. Data were analyzed with descriptive statistics. Results. The overall cumulative implant survival rate at mean follow-up time of 16 months was 97.97%. The average marginal bone loss was 0,9 mm. Conclusions. Within the limitations of this study, the results validate this treatment modality for full-arch rehabilitations with predictable outcomes and high survival rate after 2 years. PMID:26064119

  19. Skin conductance fear conditioning impairments and aggression: a longitudinal study.

    PubMed

    Gao, Yu; Tuvblad, Catherine; Schell, Anne; Baker, Laura; Raine, Adrian

    2015-02-01

    Autonomic fear conditioning deficits have been linked to child aggression and adult criminal behavior. However, it is unknown if fear conditioning deficits are specific to certain subtypes of aggression, and longitudinal research is rare. In the current study, reactive and proactive aggression were assessed in a sample of males and females when aged 10, 12, 15, and 18 years old. Skin conductance fear conditioning data were collected when they were 18 years old. Individuals who were persistently high on proactive aggression measures had significantly poorer conditioned responses at 18 years old when compared to others. This association was not found for reactive aggression. Consistent with prior literature, findings suggest that persistent antisocial individuals have unique neurobiological characteristics and that poor autonomic fear conditioning is associated with the presence of increased instrumental aggressive behavior.

  20. Skin Conductance Fear Conditioning Impairments and Aggression: A Longitudinal Study

    PubMed Central

    Gao, Yu; Tuvblad, Catherine; Schell, Anne; Baker, Laura; Raine, Adrian

    2014-01-01

    Autonomic fear conditioning deficits have been linked to child aggression and adult criminal behavior. However, it is unknown if fear conditioning deficits are specific to certain subtypes of aggression, and longitudinal research is rare. In the current study, reactive and proactive aggression were assessed in a sample of males and females when aged 10, 12, 15, and 18 years old. Skin conductance fear conditioning data were collected when they were 18 years old. Individuals who were persistently high on proactive aggression measures had significantly poorer conditioned responses at 18 years old when compared to others. This association was not found for reactive aggression. Consistent with prior literature, findings suggest that persistent antisocial individuals have unique neurobiological characteristics and that poor autonomic fear conditioning is associated with the presence of increased instrumental aggressive behavior. PMID:25174802

  1. Clinical and radiological evaluation of Trabecular Metal and the Smith-Robinson technique in anterior cervical fusion for degenerative disease: a prospective, randomized, controlled study with 2-year follow-up.

    PubMed

    Löfgren, Håkan; Engquist, M; Hoffmann, P; Sigstedt, B; Vavruch, L

    2010-03-01

    A prospective, randomized, controlled study was carried out to compare the radiological and clinical outcomes after anterior cervical decompression and fusion (ACDF) with Trabecular Metal (TM) to the traditional Smith-Robinson (SR) procedure with autograft. The clinical results of cervical fusion with autograft from the iliac crest are typically satisfactory, but implications from the donor site are frequently reported. Alternative materials for cervical body interfusion have shown lower fusion rates. Trabecular Metal is a porous tantalum biomaterial with structure and mechanical properties similar to that of trabecular bone and with proven osteoconductivity. As much as 80 consecutive patients planned for ACDF were randomized for fusion with either TM or tricortical autograft from the iliac crest (SR) after discectomy and decompression. Digitized plain radiographic images of 78 (98%) patients were obtained preoperatively and at 2-year follow-up and were subsequently evaluated by two senior radiologists. Fusion/non-fusion was classified by visual evaluation of the A-P and lateral views in forced flexion/extension of the cervical spine and by measuring the mobility between the fused vertebrae. MRI of 20 TM cases at 2 years was successfully used to assess the decompression of the neural structures, but was not helpful in determining fusion/non-fusion. Pain intensity in the neck, arms and pelvis/hip were rated by patients on a visual analog scale (VAS) and neck function was rated using the Neck Disability Index (NDI) the day before surgery and 4, 12 and 24 months postoperatively. Follow-ups at 12 and 24 months were performed by an unbiased observer, when patients also assessed their global outcome. Fusion rate in the SR group was 92%, and in the TM group 69% (P < 0.05). The accuracy of the measurements was calculated to be 2.4 degrees . Operating time was shorter for fusion with TM compared with autograft; mean times were 100 min (SD 18) and 123 min (SD 23

  2. Comprehensive study of back and leg pain improvements after adult spinal deformity surgery: analysis of 421 patients with 2-year follow-up and of the impact of the surgery on treatment satisfaction.

    PubMed

    Scheer, Justin K; Smith, Justin S; Clark, Aaron J; Lafage, Virginie; Kim, Han Jo; Rolston, John D; Eastlack, Robert; Hart, Robert A; Protopsaltis, Themistocles S; Kelly, Michael P; Kebaish, Khaled; Gupta, Munish; Klineberg, Eric; Hostin, Richard; Shaffrey, Christopher I; Schwab, Frank; Ames, Christopher P

    2015-05-01

    OBJECT Back and leg pain are the primary outcomes of adult spinal deformity (ASD) and predict patients' seeking of surgical management. The authors sought to characterize changes in back and leg pain after operative or nonoperative management of ASD. Outcomes were assessed according to pain severity, type of surgical procedure, Scoliosis Research Society (SRS)-Schwab spine deformity class, and patient satisfaction. METHODS This study retrospectively reviewed data in a prospective multicenter database of ASD patients. Inclusion criteria were the following: age > 18 years and presence of spinal deformity as defined by a scoliosis Cobb angle ≥ 20°, sagittal vertical axis length ≥ 5 cm, pelvic tilt angle ≥ 25°, or thoracic kyphosis angle ≥ 60°. Patients were grouped into nonoperated and operated subcohorts and by the type of surgical procedure, spine SRS-Schwab deformity class, preoperative pain severity, and patient satisfaction. Numerical rating scale (NRS) scores of back and leg pain, Oswestry Disability Index (ODI) scores, physical component summary (PCS) scores of the 36-Item Short Form Health Survey, minimum clinically important differences (MCIDs), and substantial clinical benefits (SCBs) were assessed. RESULTS Patients in whom ASD had been operatively managed were 6 times more likely to have an improvement in back pain and 3 times more likely to have an improvement in leg pain than patients in whom ASD had been nonoperatively managed. Patients whose ASD had been managed nonoperatively were more likely to have their back or leg pain remain the same or worsen. The incidence of postoperative leg pain was 37.0% at 6 weeks postoperatively and 33.3% at the 2-year follow-up (FU). At the 2-year FU, among patients with any preoperative back or leg pain, 24.3% and 37.8% were free of back and leg pain, respectively, and among patients with severe (NRS scores of 7-10) preoperative back or leg pain, 21.0% and 32.8% were free of back and leg pain, respectively

  3. Exploring Faculty Retirement Issues in Public 2-Year Institutions

    ERIC Educational Resources Information Center

    Conley, Valerie Martin

    2005-01-01

    Much of the research on faculty retirement focuses exclusively on 4-year institutions. This study fills a gap by describing the age distribution of faculty in public 2-year institutions, the retirement plans of these faculty, and factors related to the retirement decision-making process using data from the 1999 National Study of Postsecondary…

  4. Triadic Interaction among Newly Acquainted 2-Year-Olds

    ERIC Educational Resources Information Center

    Ishikawa, Fumiko; Hay, Dale F.

    2006-01-01

    Are children as young as 2 years old able to interact in groups of three? The study applied the family triad model first introduced by Parke, Power, and Gottman (1979) to the case of peer interaction. In Experiment 1, the model was refined for use in studies of peer interaction and applied to an existing dataset of 16 triads of newly acquainted…

  5. Phase behaviour and conductivity study of electrolytes in supercritical hydrofluorocarbons.

    PubMed

    Bartlett, Philip N; Cook, David C; George, Michael W; Ke, Jie; Levason, William; Reid, Gillian; Su, Wenta; Zhang, Wenjian

    2011-01-07

    The purpose of this work was to characterise supercritical hydrofluorocarbons (HFC) that can be used as solvents for electrodeposition. The phase behaviour of CHF(3), CH(2)F(2), and CH(2)FCF(3) containing [NBu(n)(4)][BF(4)], [NBu(n)(4)][B{3,5-C(6)H(3)(CF(3))(2)}(4)] and Na[B{3,5-C(6)H(3)(CF(3))(2)}(4)] was studied and the conditions for forming a single supercritical phase established. Although all three HFCs are good solvents for [NBu(n)(4)][BF(4)] the results show that the CH(2)F(2) system has the lowest p(r) for dissolving a given amount of [NBu(n)(4)][BF(4)]. The solubility of Na[B{3,5-C(6)H(3)(CF(3))(2)}(4)] in CH(2)F(2) was found to be unexpectedly high. Studies of the phase behaviour of CH(2)F(2) containing [NBu(n)(4)][BF(4)] and [Cu(CH(3)CN)(4)][BF(4)] showed that the copper complex was unstable in the absence of CH(3)CN. For CHF(3), [Cu(hfac)(2)] was more soluble and more stable than [Cu(CH(3)CN)(4)][BF(4)] and only increased the phase-separation pressure by a moderate amount. Studies of the conductivity of [NBu(n)(4)][B(C(6)F(5))(4)], [NBu(n)(4)][B{3,5-C(6)H(3)(CF(3))(2)}(4)], [NR(f)Bu(n)(3)][B{3,5-C(6)H(3)(CF(3))(2)}(4)] (R(f) = (CH(2))(3)C(7)F(15)), and Na[B{3,5-C(6)H(3)(CF(3))(2)}(4)] were carried out in scCH(2)F(2). The results show that these salts are more conducting than [NBu(n)(4)][BF(4)] under the same conditions although the increase is much less significant than that reported in previous work in supercritical CO(2) + CH(3)CN. Consequently, either [NBu(n)(4)][BF(4)] or the corresponding BARF salts would be suitable background electrolytes for electrodeposition from scCH(2)F(2).

  6. Electrical Conductivity and Dielectric Studies of Hydraulic Cements

    NASA Astrophysics Data System (ADS)

    Pena, Marianela Perez

    Electrical properties of portland cements and other non-portland cementitious materials have been studied at two different stages of hydration. The following relationships have been observed:. Higher water/cement (w/c) ratio (0.5 compared to 0.4) resulted in an increase of the relative permittivity and electrical conductivity of early stage hydrating materials. The relative permittivity values were close to 10('7). The phenomena giving rise to changes in electrical conductivity have been related to the heat of hydration. Higher alkali ion concentration resulted in higher electrical conductivity and relative permittivity values in cement pastes. Cations of inorganic admixtures were found to increase maximum peak of electrical conductivity and relative permittivity in the order: Ca('++) > Mg('++) > Sr('++) and K('+) (TURNEQ) Na('+) > Li('+). Dielectric properties of pressed hardened materials cured over water for 1 day with w/c = 0.20 and heat treated to 500(DEGREES)C prepared with type I, type III, and a microfine calcium silicate (MC500) cement have been compared as a function of temperature and frequency. The relative permittivity for type I hardened materials at 30(DEGREES)C was found to range from 12.5 to 9.4 at frequencies from 1 KHz to 2 MHz. The dissipation factor was found to range from 0.122 to 0.014. The relative permittivity and dissipation factors for type III hardened materials were found to range from 17.8 to 13.0 and from 0.035 to 0.071, respectively, and for MC500 hardened materials were determined to range from 7.6 to 6.9 and from 0.033 to 0.002, respectively. The activation energies determined from Arrhenius plots for the relaxation mechanism operating in these materials correspond to 0.33, 0.30, and 0.46 eV for type I, type III, and MC500 densified hardened materials, respectively. Cement/polymer composites have been prepared using 1.76 wt.% methyl cellulose polymer and a w/c ratio of 0.17. The relative permittivity and loss factor the samples

  7. A Protocol for Conducting Rainfall Simulation to Study Soil Runoff

    PubMed Central

    Kibet, Leonard C.; Saporito, Louis S.; Allen, Arthur L.; May, Eric B.; Kleinman, Peter J. A.; Hashem, Fawzy M.; Bryant, Ray B.

    2014-01-01

    Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial urea, a common form of nitrogen (N) fertilizer, following a rainfall event that occurs within 24 hr after fertilizer application. Although urea is assumed to be readily hydrolyzed to ammonium and therefore not often available for transport, recent studies suggest that urea can be transported from agricultural soils to coastal waters where it is implicated in harmful algal blooms. A rainfall simulator was used to apply a consistent rate of uniform rainfall across packed soil boxes that had been prewetted to different soil moisture contents. By controlling rainfall and soil physical characteristics, the effects of antecedent soil moisture on urea loss were isolated. Wetter soils exhibited shorter time from rainfall initiation to runoff initiation, greater total volume of runoff, higher urea concentrations in runoff, and greater mass loadings of urea in runoff. These results also demonstrate the importance of controlling for antecedent soil moisture content in studies designed to isolate other variables, such as soil physical or chemical characteristics, slope, soil cover, management, or rainfall characteristics. Because rainfall simulators are designed to deliver raindrops of similar size and velocity as natural rainfall, studies conducted under a standardized protocol can yield valuable data that, in turn, can be used to develop models for predicting the fate and transport of pollutants in runoff. PMID:24748061

  8. Ionic conductivity and battery characteristic studies of a new PAN-based Na+ ion conducting gel polymer electrolyte system

    NASA Astrophysics Data System (ADS)

    Krishna Jyothi, N.; Vijaya Kumar, K.; Sunita Sundari, G.; Narayana Murthy, P.

    2016-03-01

    Sodium ion conducting gel polymer electrolytes based on polyacrylonitrile (PAN) with ethylene carbonate and dimethyl formamide as plasticizing solvents are prepared by the solution cast technique. These electrolyte films are free standing, transparent and dimensionally stable. Na+ ions are derived from NaI. The structural properties of pure and complex formations have been examined by X-ray diffraction, Fourier transform infrared spectroscopic studies and differential scanning calorimetric studies. The variation of the conductivity with salt concentration ranging from 10 to 40 wt% is studied. The sample containing 30 wt% of NaI exhibits the highest conductivity of 2.35 × 10-4 S cm-1 at room temperature (303 K) and 1 × 10-3 S cm-1 at 373 K. The conductivity-temperature dependence of polymer electrolyte films obeys Arrhenius behavior with activation energy in the range of 0.25-0.46 eV. The transport numbers both electronic ( t e) and ionic ( t i) are evaluated using Wagner's polarization technique. It is revealed that the conducting species are predominantly due to ions. The ionic transport number of highest conducting film is found to be 0.991. Solid-state battery with configuration Na/(PAN + NaI)/(I2 + C + electrolyte) is developed using the highest conducting gel polymer electrolyte system and the discharge characteristics of the cell are evaluated over the load of 100 KΩ.

  9. River Seepage Conductance in Large-Scale Regional Studies.

    PubMed

    Morel-Seytoux, Hubert J; Miller, Calvin D; Miracapillo, Cinzia; Mehl, Steffen

    2016-12-20

    Flow exchange between surface and groundwater is of great importance be it for beneficial allocation and use of water resources or for the proper exercise of water rights. In large-scale regional studies, most numerical models use coarse grid sizes, which make it difficult to provide an accurate depiction of the phenomenon. In particular, a somewhat arbitrary leakance coefficient in a third type (i.e., Cauchy, General Head) boundary condition is used to calculate the seepage discharge as a function of the difference of head in the river and in the aquifer, whose value is often found by calibration. A different approach is presented to analytically estimate that leakance coefficient. It is shown that a simple equivalence can be deduced from the analytical solution for the empirical coefficient, so that it provides the accuracy of the analytical solution while the model maintains a very coarse grid, treating the water-table aquifer as a single calculation layer. Relating the empirical leakance coefficient to the exact conductance, derived from physical principles, provides a physical basis for the leakance coefficient. Factors such as normalized wetted perimeter, degree of penetration of the river, presence of a clogging layer, and anisotropy can be included with little computational demand. In addition the river coefficient in models such as MODFLOW, for example, can be easily modified when grid size is changed without need for recalibration.

  10. Perovskite transparent conducting oxides: an ab initio study.

    PubMed

    Dabaghmanesh, S; Saniz, R; Amini, M N; Lamoen, D; Partoens, B

    2013-10-16

    We present an ab initio study of the electronic structure and of the formation energies of various point defects in BaSnO3 and SrGeO3. We show that La and Y impurities substituting Ba or Sr are shallow donors with a preferred 1 + charge state. These defects have a low formation energy within all the suitable equilibrium growth conditions considered. Oxygen vacancies behave as shallow donors as well, preferring the 2 + charge state. Their formation energies, however, are higher in most growth conditions, indicating a limited contribution to conductivity. The calculated electron effective mass in BaSnO3, with a value of 0.21 m(e), and the very high mobility reported recently in La-doped BaSnO3 single-crystals, suggest that remarkably low scattering rates can be achieved in the latter. In the case of SrGeO3, our results point to carrier density and mobility values in the low range for typical polycrystalline TCOs, in line with experiment.

  11. A numerical study of transient, thermally-conductive solar wind

    NASA Technical Reports Server (NTRS)

    Han, S. M.; Wu, S. T.; Dryer, M.

    1987-01-01

    A numerical analysis of transient solar wind starting at the solar surface and arriving at 1 AU is performed by an implicit numerical method. The model hydrodynamic equations include thermal conduction terms for both steady and unsteady simulations. Simulation results show significant influence of thermal conduction on both steady and time-dependent solar wind. Higher thermal conduction results in higher solar wind speed, higher temperature, but lower plasma density at 1 AU. Higher base temperature at the solar surface gives lower plasma speed, lower temperature, but higher density at 1 AU. Higher base density, on the other hand, gives lower velocity, lower temperature, but higher density at 1 AU.

  12. Carbonyl mediated conductance through metal bound peptides: a computational study

    NASA Astrophysics Data System (ADS)

    Perrine, Trilisa M.; Dunietz, Barry D.

    2007-10-01

    Large increases in the conductance of peptides upon binding to metal ions have recently been reported experimentally. The mechanism of the conductance switching is examined computationally. It is suggested that oxidation of the metal ion occurs after binding to the peptide. This is caused by the bias potential placed across the metal-peptide complex. A combination of configurational changes, metal ion involvement and interactions between carbonyl group oxygen atoms and the gold leads are all shown to be necessary for the large improvement in the conductance seen experimentally. Differences in the molecular orbitals of the nickel and copper complexes are noted and serve to explain the variation of the improvement in conductance upon binding to either a nickel or copper ion.

  13. Comparative Study of the Thermal Conductivity of Solid Biomass Fuels

    PubMed Central

    2016-01-01

    The thermal conductivity of solid biomass fuels is useful information in the investigation of biomass combustion behavior and the development of modeling especially in the context of large scale power generation. There are little published data on the thermal conductivity of certain types of biomass such as wheat straw, miscanthus, and torrefied woods. Much published data on wood is in the context of bulk materials. A method for determining the thermal conductivities of small particles of biomass fuels has been developed using a custom built test apparatus. Fourteen different samples of various solid biomass fuel were processed to form a homogenized pellet for analysis. The thermal conductivities of the pelletized materials were determined and compared against each other and to existing data. PMID:27041819

  14. Molecular Dynamics study of the mixed oxide fuel thermal conductivity

    NASA Astrophysics Data System (ADS)

    Nichenko, S.; Staicu, D.

    2013-08-01

    There is still no clear understanding of the plutonium content influence on the thermal conductivity behaviour of the (U,Pu) O2 MOX fuels. In this work Classical Molecular Dynamics (MD) was used to investigate the (U,Pu) O2 thermal conductivity in the whole concentration range and in the temperature range from 400 K to 1600 K. The Green-Kubo approach was used for the thermal conductivity calculation and an algorithm was proposed to improve the accuracy of the calculation. The obtained results are in good agreement with the literature experimental data and results of modelling of other authors. On the basis of the obtained results we give recommendations for the MOX thermal conductivity evaluation in the concentration range from pure UO2 up to pure PuO2.

  15. Repetitive Behaviours in Typically Developing 2-Year-Olds

    ERIC Educational Resources Information Center

    Leekam, Susan; Tandos, Jonathan; McConachie, Helen; Meins, Elizabeth; Parkinson, Kathryn; Wright, Charlotte; Turner, Michelle; Arnott, Bronia; Vittorini, Lucia; Le Couteur, Ann

    2007-01-01

    Background: Repetitive behaviours are an essential part of the diagnosis of autism but are also commonly seen in typically developing children. The current study investigated the frequency and factor structure of repetitive behaviours in a large community sample of 2-year-olds. Methods: A new measure, the Repetitive Behaviour Questionnaire (RBQ-2)…

  16. Association between inflammatory cytokines and the risk of post-stroke depression, and the effect of depression on outcomes of patients with ischemic stroke in a 2-year prospective study

    PubMed Central

    Jiao, Jian-Tong; Cheng, Chao; Ma, Ying-Jun; Huang, Jin; Dai, Min-Chao; Jiang, Chen; Wang, Cheng; Shao, Jun-Fei

    2016-01-01

    The association between inflammatory cytokines and the risk of post-stroke depression (PSD) remains unclear. The aim of the present study was to investigate this association and the effect of PSD on the outcomes of ischemic stroke patients. A total of 355 patients who had experienced ischemic stroke participated in inflammatory cytokine detection by ELISA, in addition to depression, quality of life (QOL) and body performance testing. Cox regression was used to evaluate the associations between PSD risk, inflammatory cytokines and the outcomes of patients. Measurement data was evaluated using Student's t test, and counted data was measured by χ2 test. The incidence of PSD during the 2-year follow-up was 23.1%. The risk of PSD elevated with increased interleukin (IL)-6 expression levels [hazard ratio (HR)=3.18; 95% confidence interval (CI), 1.37–7.36] following the adjustment of confounders. However, no significant associations were identified between PSD and other inflammatory cytokines. QOL and body performance in the depressed group were significantly worse compared with those in the non-depressed group. The risk of stroke recurrence in patients with depression increased two-fold compared with patients without depression (HR=2.020; 95% CI, 1.123–3.635; Ptrend=0.019). No significant associations between PSD and the risk of mortality (HR=1.497; 95% CI, 0.547–4.098) were observed. In conclusion, depression is prevalent in patients following ischemic stroke. IL-6 is positively associated with the risk of PSD, and may predict its development in patients following ischemic stroke. PSD correlates with outcomes of patients, and the effective management of PSD may improve the prognosis of patients. PMID:27588080

  17. Electrical Characterization and Morphological Studies of Conducting Polymer Nanofibers

    NASA Technical Reports Server (NTRS)

    Pinto, N. J.; Zhou, Y. X.; Freitag, M.; Johnson, A. T.; MacDiarmid, A. G.; Mueller, C. H.; Theofylaktos, N.; Robinson, D. C.; Miranda, F. A.

    2003-01-01

    Doped polyaniline blended with poly(ethylene oxide) has been electrospun in air to give fibers with diameters in the range 3 nm 200 nm. These fibers were captured on wafers of degenerately doped Si/SiO2 by placing the wafer in the path of the fiber jet formed during the electrospinning process. Individual fibers were contacted using shadow mask evaporation and were also captured on prepatterned wafers. Fibers having diameters greater than 100 nm show a slight increase in the conductivity as compared to the bulk film, while fibers with diameters less than 30 nm had lower conductivity than the bulk. Data on Scanning Conductance Microscopy along the length of individual fibers will be presented. For fibers where the diameter was not uniform, we found that below a certain diameter ( approx.15 nm) the fiber was less conducting as compared to thicker diameter fibers. Dependence of the fiber conductivity on a gate bias is underway and these results will also be presented.

  18. Materials characterization study of conductive flexible second surface mirrors

    NASA Technical Reports Server (NTRS)

    Levadou, F.; Bosma, S. J.; Paillous, A.

    1981-01-01

    The status of prequalification and qualification work on conductive flexible second surface mirrors is described. The basic material is FEP Teflon witn either aluminium or silver vacuum deposited reflectors. The top layer has been made conductive by deposition of layer of a indium oxide. The results of a prequalification program comprised of decontamination, humidity, thermal cycling, thermal shock and vibration tests are presented. Thermo-optical and electrical properties. The results of a prequalification program comprised of decontamination, humidity, thermal cycling, thermal shock and vibration tests are presented. Thermo-optical and electrical properties, the electrostatic behavior of the materials under simulated substorm environment and electrical conductivity at low temperatures are characterized. The effects of simulated ultra violet and particles irradiation on electrical and thermo-optical properties of the materials are also presented.

  19. Mössbauer study of conductive oxide glass

    SciTech Connect

    Matsuda, Koken; Kubuki, Shiro; Nishida, Tetsuaki

    2014-10-27

    Heat treatment of barium iron vanadate glass, BaO‐Fe{sub 2}O{sub 3}‐V{sub 2}O{sub 5}, at temperatures higher than crystallization temperature causes a marked decrease in resistivity (ρ) from several MΩcm to several Ωcm. {sup 57}Fe Mössbauer spectrum of heat-treated vanadate glass shows a marked decrease in quadrupole splitting (Δ) of Fe{sup III}, reflecting a structural relaxation, i.e., an increased symmetry of 'distorted' FeO{sub 4} and VO{sub 4} tetrahedra which are connected to each other by sharing corner oxygen atoms. Structural relaxation of 3D-network of vanadate glass accompanies a decrease in the activation energy for the conduction, reflecting a decreased energy gap between the donor level and conduction band. A marked increase in the conductivity was observed in CuO- or Cu{sub 2}O-containing barium iron vanadate glass after heat treatment at 450 °C for 30 min or more. 'n-type semiconductor model combined with small polaron hopping theory' was proposed in order to explain the high conductivity.

  20. A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

    PubMed

    Yamagata, Toru; Naito, Kentaro; Arima, Hironori; Yoshimura, Masaki; Ohata, Kenji; Takami, Toshihiro

    2016-07-01

    Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion.

  1. Comparative study of ion conducting pathways in borate glasses

    SciTech Connect

    Hall, Andreas; Swenson, Jan; Adams, Stefan

    2006-11-01

    The conduction pathways in metal-halide doped silver, lithium, and sodium diborate glasses have been examined by bond valence analysis of reverse Monte Carlo (RMC) produced structural models of the glasses. Although all glass compositions have basically the same short-range structure of the boron-oxygen network, it is evident that the intermediate-range structure is strongly dependent on the type of mobile ion. The topography of the pathways and the coordination of the pathway sites differ distinctly between the three glass systems. The mobile silver ions in the AgI-doped glass tend to be mainly iodine-coordinated and travel in homogeneously distributed pathways located in salt-rich channels of the borate network. In the NaCl-doped glass, there is an inhomogeneous spatial distribution of pathways that reflects the inhomogeneous introduction of salt ions into the glass. However, since the salt clusters are not connected, no long-range conduction pathways are formed without including also oxygen-rich regions. The pathways in the LiCl-doped glass are slightly more evenly distributed compared to the NaCl-doped glass (but not as ordered as in the AgI-doped glass), and the regions of mainly oxygen-coordinated pathway sites are of higher importance for the long-range migration. In order to more accurately investigate how these differences in the intermediate-range order of the glasses affect the ionic conductivity, we have compared the realistic structure models to more or less randomized structures. An important conclusion from this comparison is that we find no evidence that a pronounced intermediate-range order in the atomic structure or in the network of conduction pathways, as in the AgI-doped glass, is beneficial for the dc conductivity.

  2. Performance of p16INK4a ELISA as a primary cervical cancer screening test among a large cohort of HIV-infected women in western Kenya: a 2-year cross-sectional study

    PubMed Central

    Wu, Tara J; Smith-McCune, Karen; Reuschenbach, Miriam; von Knebel Doeberitz, Magnus; Maloba, May; Huchko, Megan J

    2016-01-01

    Objective A biomarker with increased specificity for cervical dysplasia compared with human papillomavirus (HPV) testing would be an attractive option for cervical cancer screening among HIV-infected women in resource-limited settings. p16INK4a has been explored as a biomarker for screening in general populations. Design A 2-year cross-sectional study. Setting 2 large HIV primary care clinics in western Kenya. Participants 1054 HIV-infected women in western Kenya undergoing cervical cancer screening as part of routine HIV care from October 2010 to November 2012. Interventions Participants underwent p16INK4a specimen collection and colposcopy. Lesions with unsatisfactory colposcopy or suspicious for cervical intraepithelial neoplasia 2+ (CIN2+; including CIN2/3 or invasive cervical cancer) were biopsied. Following biopsy, disease status was determined by histopathological diagnosis. Primary and secondary outcome measures We measured the sensitivity, specificity and predictive values of p16INK4a ELISA for CIN2+ detection among HIV-infected women and compared them to the test characteristics of current screening methods used in general as well as HIV-infected populations. Results Average p16INK4a concentration in cervical samples was 37.4 U/mL. After colposcopically directed biopsy, 127 (12%) women were determined to have CIN2+. Receiver operating characteristic analysis showed an area under the curve of 0.664 for p16INK4a to detect biopsy-proven CIN2+. At a p16INK4a cut-off level of 9 U/mL, sensitivity, specificity, positive and negative predictive values were 89.0%, 22.9%, 13.6% and 93.8%, respectively. The overall p16INK4a positivity at a cut-off level of 9 U/mL was 828 (78.6%) women. There were 325 (30.8%) cases of correct p16INK4a prediction to detect or rule out CIN2+, and 729 (69.2%) cases of incorrect p16INK4a prediction. Conclusions p16INK4a ELISA did not perform well as a screening test for CIN2+ detection among HIV-infected women due to low

  3. Smoking Patterns, Attitudes and Motives: Unique Characteristics among 2-Year versus 4-Year College Students

    ERIC Educational Resources Information Center

    Berg, C. J.; An, L. C.; Thomas, J. L.; Lust, K. A.; Sanem, J. R.; Swan, D. W.; Ahluwalia, J. S.

    2011-01-01

    Given the previously documented higher rates of smoking among 2-year college students in comparison with 4-year university students, this study compares smoking patterns, attitudes and motives among 2-year and 4-year college students. Two thousand two hundred and sixty-five undergraduate students aged 18-25 years at a 2-year college and a 4-year…

  4. Nuclear Spin Lattice Relaxation and Conductivity Studies of the Non-Arrhenius Conductivity Behavior in Lithium Fast Ion Conducting Sulfide Glasses

    SciTech Connect

    Meyer, Benjamin Michael

    2003-01-01

    As time progresses, the world is using up more of the planet's natural resources. Without technological advances, the day will eventually arrive when these natural resources will no longer be sufficient to supply all of the energy needs. As a result, society is seeing a push for the development of alternative fuel sources such as wind power, solar power, fuel cells, and etc. These pursuits are even occurring in the state of Iowa with increasing social pressure to incorporate larger percentages of ethanol in gasoline. Consumers are increasingly demanding that energy sources be more powerful, more durable, and, ultimately, more cost efficient. Fast Ionic Conducting (FIC) glasses are a material that offers great potential for the development of new batteries and/or fuel cells to help inspire the energy density of battery power supplies. This dissertation probes the mechanisms by which ions conduct in these glasses. A variety of different experimental techniques give a better understanding of the interesting materials science taking place within these systems. This dissertation discusses Nuclear Magnetic Resonance (NMR) techniques performed on FIC glasses over the past few years. These NMR results have been complimented with other measurement techniques, primarily impedance spectroscopy, to develop models that describe the mechanisms by which ionic conduction takes place and the dependence of the ion dynamics on the local structure of the glass. The aim of these measurements was to probe the cause of a non-Arrhenius behavior of the conductivity which has been seen at high temperatures in the silver thio-borosilicate glasses. One aspect that will be addressed is if this behavior is unique to silver containing fast ion conducting glasses. more specifically, this study will determine if a non-Arrhenius correlation time, τ, can be observed in the Nuclear Spin Lattice Relaxation (NSLR) measurements. If so, then can this behavior be modeled with a new single distribution of

  5. Ionic Conductivity And Structural Relaxation Studies on Lithium Niobophosphate Glass

    SciTech Connect

    Dabas, Prashant; Hariharan, K.

    2011-07-15

    Niobium pentoxide (Nb{sub 2}O{sub 5}) increases the chemical and thermal stability of otherwise hygroscopic alkali phosphate glasses and also enhances the conduction characteristics. Ion dynamics and structural relaxation have been investigated for mol%50Li{sub 2}0-45P{sub 2}0{sub 5}-5Nb{sub 2}O{sub 5}. The non-linearity parameter 'x' in the Tool-Narayanaswamy model is evaluated using the dependence of fictive and glass transition temperatures on the cooling and heating rates.

  6. Molecular modelling approaches for cystic fibrosis transmembrane conductance regulator studies.

    PubMed

    Odolczyk, Norbert; Zielenkiewicz, Piotr

    2014-07-01

    Cystic fibrosis (CF) is one of the most common genetic disorders, caused by loss of function mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein. CFTR is a member of ATP-binding cassette (ABC) transporters superfamily and functions as an ATP-gated anion channel. This review summarises the vast majority of the efforts which utilised molecular modelling approaches to gain insight into the various aspects of CFTR protein, related to its structure, dynamic properties, function and interactions with other protein partners, or drug-like compounds, with emphasis to its relation to CF disease.

  7. Distance-Dependent Measurements of the Conductance of Porphyrin Nanorods Studied with Conductive Probe Atomic Force Microscopy.

    PubMed

    Zhai, Xianglin; Alexander, Denzel; Derosa, Pedro; Garno, Jayne C

    2017-02-07

    Protocols for nanopatterning porphyrins on Au(111) were developed based on immersion particle lithography. Porphyrins with and without a central metal ion, 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin cobalt(II) (CoTPP), were selected for study, which spontaneously formed nanorod geometries depending on concentration parameters. The elongated shapes of the nanorods offers an opportunity for successive distance-dependent conductive probe atomic force microscopy (CP-AFM) measurements along the length of the nanorods. To prepare patterns of TPP and CoTPP nanorods, a mask of silica mesospheres was placed on gold substrates to generate nanoholes within an alkanethiol matrix film. The nanoholes prepared by particle lithography with an immersion step were backfilled with porphyrins by a second immersion step. By controlling the concentration and immersion interval, nanorods of porphyrins were generated with one end of the nanostructure attached to gold within a nanohole. The porphyrin nanorods exhibited slight differences in dimensions at the nanoscale to enable size-dependent measurements of conductive properties. The conductivity along the horizontal direction of the nanorods was evaluated with CP-AFM studies. Changes in conductivity were measured along the long axis of TPP and CoTPP nanorods. The TPP nanorods exhibited conductive profiles of an insulating material, and the CoTPP nanorods exhibited profiles of a semiconductor. The experiments demonstrate the applicability of particle lithography for preparing unique and functional surface platforms of porphyrins to measure distance-dependent conductive properties on gold.

  8. Scanning Ion Conductance Microscopy for Studying Biological Samples

    PubMed Central

    Happel, Patrick; Thatenhorst, Denis; Dietzel, Irmgard D.

    2012-01-01

    Scanning ion conductance microscopy (SICM) is a scanning probe technique that utilizes the increase in access resistance that occurs if an electrolyte filled glass micro-pipette is approached towards a poorly conducting surface. Since an increase in resistance can be monitored before the physical contact between scanning probe tip and sample, this technique is particularly useful to investigate the topography of delicate samples such as living cells. SICM has shown its potential in various applications such as high resolution and long-time imaging of living cells or the determination of local changes in cellular volume. Furthermore, SICM has been combined with various techniques such as fluorescence microscopy or patch clamping to reveal localized information about proteins or protein functions. This review details the various advantages and pitfalls of SICM and provides an overview of the recent developments and applications of SICM in biological imaging. Furthermore, we show that in principle, a combination of SICM and ion selective micro-electrodes enables one to monitor the local ion activity surrounding a living cell. PMID:23202197

  9. NAFTA Guidance Document for Conducting Terrestrial Field Dissipation Studies

    EPA Pesticide Factsheets

    Harmonized guidance for TFD studies that demonstrate transformation, transport and fate of pesticides under representative actual use conditions. Field studies substantiate physicochemical, mobility and biotransformation data from laboratory studies.

  10. Nuclear spin lattice relaxation and conductivity studies of the non-Arrhenius conductivity behavior in lithium fast ion conducting sulfide glasses

    NASA Astrophysics Data System (ADS)

    Meyer, Benjamin Michael

    Homogeneous xB2O3 + (1-x)B 2S3 glasses were prepared between 0 ≤ x ≤ 0.80. Raman, IR, and 11B NMR spectroscopies show that the boron oxide structures of B2O3, especially the six-membered rings, quickly diminish with increasing sulfide content, whereas the corresponding sulfide structures in B2S3 remain relatively intense as oxide content is increased. Differential scanning calorimetry (DSC) and density measurements show that physical properties of these boron oxysulfide glasses heavily favor the B2S3 properties regardless of the amount of B2O3 added to the system. It is hypothesized that the stability of the thioboroxol ring group relative to that of the BS 3/2 trigonal group is a possible source of this behavior. The formation of mixed boron oxysulfide structures of composition BSzO3-z where 0 < z < 3 is proposed. Structural studies of the ternary xLi2S + (1-x)[0.5 B2S3 + 0.5 GeS2] glasses using IR, Raman, and 11B NMR show that these glasses do not have equal sharing of the lithium atoms between GeS2 and B2S3. The IR spectra indicates that the B2S3 glass network are under-doped in comparison to corresponding compositions in the xLi 2S + (1-x)B2S3 binary system. Additionally, the Raman spectra show that the GeS2 glass network is over-modified. 11Boron static NMR gives evidence that ˜80% of the boron atoms are in tetrahedral coordinated. A super macro tetrahedron is proposed as one of the structures in these glasses in which some of them may contain boron sites substituted by germanium atoms at lower Li2S content. Nuclear Spin Lattice Relaxation and ionic conductivity measurements of Li doped Li2S + GeS2 + B2S3 glasses were performed to investigate the ion hopping dynamics and the non-Arrhenius conductivity behavior that has been observed in some fast ion conducting glasses. A distribution of activation energies model was used to fit the NSLR results and conductivity results. Comparisons are made to previously studied binary lithium thio-germanate and binary

  11. [Molecular genetic study of a family featuring cardiac conduction block].

    PubMed

    Tan, Xiaojun; Huang, He; Zhu, Li; Lu, Yongjuan; Jiang, Yunshan; Li, Hui; Huang, Xianghong; Sun, Zhishan; Li, Zhihong

    2015-10-01

    OBJECTIVE To explore the genetic mechanism for a family affected with cardiac conduction block. METHODS Affected family members were screened for potential mutations of known candidate genes. As no pathogenic mutation was found, two patients and one healthy member from the family were further analyzed by exomic sequencing followed by Sanger sequencing. The pathogenicity of suspected mutation was analyzed using bioinformatics software. RESULTS Sequencing of the full exome has identified a c.G1725T mutation in the CLCA2 gene. Sanger sequencing has detected the same mutation in all five patients, but not in the normal member from the family. Bioinformatics analysis indicated that the mutation has resulted in substitution of the 575th amino acid cysteine (C) by tryptophan (W). The site is highly conserved and becomes pathogenic with the mutation. CONCLUSION The heterozygous c.G1725T mutation in exon 11 of the CLCA2 gene probably underlies the disease and fit the autosomal dominant pattern of inheritance.

  12. Scanning ion conductance microscopy studies of amyloid fibrils at nanoscale

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Cho, Sang-Joon; Busuttil, Katerina; Wang, Chen; Besenbacher, Flemming; Dong, Mingdong

    2012-05-01

    Atomic force microscopy (AFM) has developed to become a very versatile nano-scale technique to reveal the three-dimensional (3D) morphology of amyloid aggregates under physiological conditions. However, the imaging principle of AFM is based on measuring the `force' between a sharp tip and a given nanostructure, which may cause mechanical deformation of relatively soft objects. To avoid the deformation, scanning ion conductance microscopy (SICM) is an alternative scanning probe microscopy technique, operating with alternating current mode. Here we can indeed reveal the 3D morphology of amyloid fibrils and it is capable of exploring proteins with nanoscale resolution. Compared with conventional AFM, we show that SICM can provide precise height measurements of amyloid protein aggregates, a feature that enables us to obtain unique insight into the detailed nucleation and growth mechanisms behind amyloid self-assembly.

  13. Interface proximity effects on ionic conductivity in nanoscale oxide-ion conducting yttria stabilized zirconia: an atomistic simulation study.

    PubMed

    Sankaranarayanan, Subramanian K R S; Ramanathan, Shriram

    2011-02-14

    We present an atomistic simulation study on the size dependence of dopant distribution and the influence of nanoscale film thickness on carrier transport properties of the model oxide-ion conductor yttria stabilized zirconia (YSZ). Simulated amorphization and recrystallization approach was utilized to generate YSZ films with varying thicknesses (3-9 nm) on insulating MgO substrates. The atomic trajectories generated in the molecular dynamics simulations are used to study the structural evolution of the YSZ thin films and correlate the resulting microstructure with ionic transport properties at the nanoscale. The interfacial conductivity increases by 2 orders of magnitude as the YSZ film size decreases from 9 to 3 nm owing to a decrease in activation energy barrier from 0.54 to 0.35 eV in the 1200-2000 K temperature range. Analysis of dopant distribution indicates surface enrichment, the extent of which depends on the film thickness. The mechanisms of oxygen conductivity for the various film thicknesses at the nanoscale are discussed in detail and comparisons with experimental and other modeling studies are presented where possible. The study offers insights into mesoscopic ion conduction mechanisms in low-dimensional solid oxide electrolytes.

  14. Procedures for Conducting Installation Compatible Use Zone (ICUZ) studies

    DTIC Science & Technology

    1988-08-01

    literature was also surveyed; findings are reviewed briefly in Appendix B. The most common questions about ICUZ studies are: e What is ICUZ? e What are the...steps in preparing an ICUZ study? a What roles do various members of an ICUZ committee play? * What kinds of information should be contained in the ICUZ...study? * How can this information be gathered? * How should this information be presented? * What should be done with the ICUZ study after it is

  15. The Study of Diagnostic Efficacy of Nerve Conduction Study Parameters in Cervical Radiculopathy

    PubMed Central

    Pawar, Sachin; Kashikar, Aditi; Shende, Vinod; Waghmare, Satish

    2013-01-01

    Background: Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria. Aim: To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy. Setting and Design: It was a cross-sectional study conducted on 100 subjects of age > 40 years. Material and Methods: The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves. Statistical Analysis: Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0. Results: Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared

  16. 43 CFR 404.18 - How can I request assistance to conduct a feasibility study?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... feasibility study? 404.18 Section 404.18 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... request assistance to conduct a feasibility study? To request assistance to conduct a feasibility study... submit a full proposal to conduct a feasibility study in response to the program announcement,...

  17. 43 CFR 404.18 - How can I request assistance to conduct a feasibility study?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... feasibility study? 404.18 Section 404.18 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... request assistance to conduct a feasibility study? To request assistance to conduct a feasibility study... submit a full proposal to conduct a feasibility study in response to the program announcement,...

  18. Conducting influenza virus pathogenesis studies in avian species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian infection studies with influenza A are an important means of assessing host susceptibility, viral pathogenesis, host responses to infection, mechanisms of transmission and viral pathotype. Complex systems and natural settings may also be explored with carefully designed infection studies. In ...

  19. Guidelines for conducting Smolt survival studies in the Columbia River

    USGS Publications Warehouse

    Giorgi,; Skalski,; Pevin,; Smith,; Langeslay,; Counihan, Timothy D.; Perry, Russell W.; Bickford, Shane

    2010-01-01

    For more than a decade, investigators from different research groups in the Pacific Northwest have been using electronic tags to estimate survival of salmonid smolts as they migrate seaward past hydroelectric dams and through impoundments on the Snake and Columbia Rivers. Over the years, they have refined both analytical and field methods associated with such studies. In this collaborative paper, they synthesize years of experience to formulate a set of guidelines that may assist others with the design and execution of survival studies involving smolts during their migratory phase.

  20. Issues in Conducting an Institutional Salary-Equity Study.

    ERIC Educational Resources Information Center

    Ferber, Marianne A.; Loeb, Jane W.

    2002-01-01

    Discusses how the selection of variables used in the salary model, and the functional form of the salary model, can influence the findings from an institutional salary-equity study. Also demonstrates how an institution's salary model can be used to identify pay disparities for individual faculty members. (EV)

  1. A protocol for conducting rainfall simulation to study soil runoff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial ur...

  2. Involvement of Professional Staff in Conducting an Organizational Study.

    ERIC Educational Resources Information Center

    Thibodeau, Janice A.; Vance, Carmen L.

    1986-01-01

    An organizational study of the residential life staff shows responses on time, personal and physical space, and motivation and morale. Provides a systematic, objective database upon which to develop departmental objectives and priorities. Affords staff the opportunity to further develop research skills and to work on team-building skills.…

  3. A NASA DC-8 conducts high-altitude hurricane studies

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This NASA Dryden Flight Research Center DC-8 takes off from Patrick Air Force Base to pursue its goal of collecting high- altitude information about Atlantic hurricanes and tropical storms. Flying at 35,000 to 40,000 feet, the plane is equipped with instruments to measure the storm's structure, environment and changes in intensity and tracking. The DC-8 is part of the NASA-led Atmospheric Dynamics and Remote Sensing program that includes other government weather researchers and the university community in a study of Atlantic hurricanes and tropical storms. The hurricane study, which lasts through September, is part of NASA's Earth Science enterprise to better understand the total Earth system and the effects of natural and human-induced changes on the global environment.

  4. Recent propeller development and studies conducted at ONERA

    NASA Astrophysics Data System (ADS)

    Jouaillec, F.

    Based on recent research, the common interests that exist between aeronautical and naval propeller design is presented. A review of aeronautical propeller evolution up to the introduction of unducted fan technology is offered, along with a history of the marine propeller. Specific areas covered include airflow calculation through Euler three-dimensional methodology, acoustic calculations for discrete-frequency noise of helicopter rotors, and vibration studies of aircraft and ship propellers. Similarity of test results and possible commonality applications for the two propeller types are discussed.

  5. Analysis of the clinical effects of transforaminal endoscopic discectomy on lumbar disk herniation combined with common peroneal nerve paralysis: a 2-year follow-up retrospective study on 32 patients

    PubMed Central

    Wang, Ya-peng; Zhang, Wei; Zhang, Jian; Sun, Ya-peng; An, Ji-long; Ding, Wen-yuan

    2017-01-01

    Background Very few studies have discussed transforaminal endoscopic discectomy (TED) in the treatment of common peroneal nerve paralysis induced by lumbar disk herniation (LDH). This study aimed to evaluate the efficacy of TED in the treatment of LDH combined with common peroneal nerve paralysis. Materials and methods The clinical and follow-up data of 32 patients with common peroneal nerve paralysis induced by LDH undergoing TED from March 2011 to April 2014 were retrospectively analyzed in this study. Follow-up was conducted immediately after the surgery, as well as 3, 12, and 24 months postoperatively. The parameters (including muscle strength recovery of the anterior tibial muscle, leg pain visual analog scale score, neurological function Japanese Orthopaedic Association [JOA] score, MacNab scores in the last follow-up, and the intraoperative and postoperative complications) were recorded. Results Three patients (9.4%) had the anterior tibial muscle strength recovered to ≥ grade 4 immediately after the surgery. The anterior tibial muscle strength of patients recovered to basically stable form in the 6-month postoperative follow-up and that in the last follow-up were as follows: one case of grade 1, one case of grade 2, 28 cases of grade 4, and two cases of grade 5. The visual analog scale scores of leg pain were significantly reduced immediately after the surgery and also on 3, 12, and 24 months compared with preoperative period (all P<0.05). The postoperative JOA scores in the last follow-up were significantly higher than the preoperative JOA scores (P<0.05), and there were nine excellent cases (28.2%), 21 good cases (65.6%), one fair case (3.1%) and one poor case (3.1%) in the last follow-up, with an overall excellent and good rate of 93.8%. Conclusion TED, which can offer sufficient decompression of the nerve root, has excellent overall clinical effects in treating common peroneal nerve paralysis induced by LDH. PMID:28115870

  6. 41 CFR 101-5.104-6 - Conduct of feasibility studies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... FEDERAL BUILDINGS AND COMPLEXES 5.1-General § 101-5.104-6 Conduct of feasibility studies. An initial... and detailed procedures to be followed in the conduct of each feasibility study. Arrangements will be... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Conduct of...

  7. Feeding Your 1- to 2-Year-Old

    MedlinePlus

    ... to 2-Year-Old Feeding Your 1- to 2-Year-Old KidsHealth > For Parents > Feeding Your 1- to 2-Year-Old Print A A A What's in ... español Alimentar a su hijo de 1 a 2 años de edad Toddlers this age are moving ...

  8. Growth and Your 1- to 2-Year-Old

    MedlinePlus

    ... 2-Year-Old Growth and Your 1- to 2-Year-Old KidsHealth > For Parents > Growth and Your 1- to 2-Year-Old Print A A A You're ... down. Your toddler may gain about 5 pounds (2.27 kg) and grow about 4 or 5 ...

  9. An Examination of University Conducting Faculty Members' Score Study Attitudes and Practices

    ERIC Educational Resources Information Center

    Silvey, Brian A.; Springer, D. Gregory; Eubanks, Stephen C.

    2016-01-01

    The purpose of this study was to examine university conducting teachers' attitudes about score study, the source materials they used to teach score study, their personal score study practices, and the score study approaches they taught their undergraduate conducting students. Respondents (N = 236) were members of the College Band Directors…

  10. 43 CFR 404.47 - How will a feasibility study be conducted under this program?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false How will a feasibility study be conducted... Studies § 404.47 How will a feasibility study be conducted under this program? Feasibility studies will be... feasibility study, including the Principles and Guidelines (incorporated by reference at § 404.4). You...

  11. 43 CFR 404.47 - How will a feasibility study be conducted under this program?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false How will a feasibility study be conducted... Studies § 404.47 How will a feasibility study be conducted under this program? Feasibility studies will be... feasibility study, including the Principles and Guidelines (incorporated by reference at § 404.4). You...

  12. Design and Conduct of the CALERIE Study: Comprehensive Assessment of the Long-term Effects of Reducing Intake of Energy

    PubMed Central

    Bales, Connie W.; Ravussin, Eric; Redman, Leanne M.; Holloszy, John O.; Racette, Susan B.; Roberts, Susan B.; Das, Sai Krupa; Romashkan, Sergei; Galan, Katherine M.; Hadley, Evan C.; Kraus, William E.

    2011-01-01

    Background. In a robust and consistent manner, sustained caloric restriction (CR) has been shown to retard the aging process in a variety of animal species. Nonhuman primate studies suggest that CR may have similar effects in longer-lived species. The CALERIE (Comprehensive Assessment of the Long-term Effects of Reducing Intake of Energy) research program is the first systematic investigation of CR in nonobese human beings. In the phase 2 study, it is hypothesized that 2 years of sustained CR, involving a 25% reduction of ad libitum energy intake, results in beneficial effects similar to those observed in animal studies. This article presents the design and implementation of this study. Methods. The study is a multicenter, parallel-group, randomized controlled trial. A sample of 225 participants (22.0 ≤ body mass index [BMI] < 28.0 kg/m2) is being enrolled with 2:1 allocation to CR. Results. An intensive dietary and behavioral intervention was developed to achieve 25% CR and sustain it over the 2 years. Adherence is monitored using a doubly labeled water technique. Primary outcomes are resting metabolic rate and core temperature, and are assessed at baseline and at 6-month intervals. Secondary outcomes address oxyradical formation, cardiovascular risk markers, insulin sensitivity and secretion, immune function, neuroendocrine function, quality of life and cognitive function. Biologic materials are stored in a central repository. Conclusions. An intricate protocol has been developed to conduct this study. Procedures have been implemented to safeguard the integrity of the data and the conclusions drawn. The results will provide insight into the detrimental changes associated with the human aging process and how CR mitigates these effects. PMID:20923909

  13. Social competence at 2 years following child traumatic brain injury.

    PubMed

    Anderson, Vicki; Beauchamp, Miriam Helen; Yeates, Keith Owen; Crossley, Louise; Ryan, Nicholas Peter; Hearps, Stephen J C; Catroppa, Cathy

    2017-02-08

    Children with traumatic brain injury (TBI) are at risk of social impairment, but research is yet to document the trajectory of these skills post-injury and factors that may predict social problems. The study addressed these gaps in knowledge, reporting on findings from a prospective, longitudinal follow-up study which investigated social outcomes post injury and explored factors contributing to these outcomes at 2 years post-injury. The sample included 113 children, 74 with TBI and 39 typically developing (TD) controls. TBI participants were recruited on presentation to hospital. Parents rated pre-injury function at that time and all children underwent magnetic resonance imaging (MRI) scan. Participants were followed up at 2 years post-injury. Outcomes were social adjustment, social participation, social relationships, and social cognition. Predictors of social outcomes examined included brain lesion characteristics, child cognition (6 months post-TBI) and behavior and environmental factors (pre-injury and 2 years). Reduced social adjustment (p=.011) and social participation (p<.001) were evident in children with TBI compared to TD controls. Poor social adjustment was predicted by externalizing behaviour problems and younger age at injury. Reduced social participation was linked to internalizing behavior problems. Greater lesion volume, lower socioeconomic status and family burden contributed to poorer social relationships, while age at injury predicted social cognition. Within the TBI group, 23% of children exhibited social impairment: younger age at injury, greater pre-injury and current behavior problems and family dysfunction, poorer IQ, processing speed, and empathy were linked to impairment. Further follow-up is required to track social recovery and the influences of cognition, brain, and environment over time.

  14. The association of maternal vitamin D status with infant birth outcomes, postnatal growth and adiposity in the first 2 years of life in a multi-ethnic Asian population: the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort study.

    PubMed

    Ong, Yi Lin; Quah, Phaik Ling; Tint, Mya Thway; Aris, Izzuddin M; Chen, Ling Wei; van Dam, Rob M; Heppe, Denise; Saw, Seang-Mei; Godfrey, Keith M; Gluckman, Peter D; Chong, Yap Seng; Yap, Fabian; Lee, Yung Seng; Foong-Fong Chong, Mary

    2016-08-01

    Maternal vitamin D status during pregnancy has been associated with infant birth and postnatal growth outcomes, but reported findings have been inconsistent, especially in relation to postnatal growth and adiposity outcomes. In a mother-offspring cohort in Singapore, maternal plasma vitamin D was measured between 26 and 28 weeks of gestation, and anthropometric measurements were obtained from singleton offspring during the first 2 years of life with 3-month follow-up intervals to examine birth, growth and adiposity outcomes. Associations were analysed using multivariable linear regression. Of a total of 910 mothers, 13·2 % were vitamin D deficient (<50 nmol/l) and 26·5 % were insufficient (50-75 nmol/l). After adjustment for potential confounders and multiple testing, no statistically significant associations were observed between maternal vitamin D status and any of the birth outcomes - small for gestational age (OR 1·00; 95 % CI 0·56, 1·79) and pre-term birth (OR 1·16; 95 % CI 0·64, 2·11) - growth outcomes - weight-for-age z-scores, length-for-age z-scores, circumferences of the head, abdomen and mid-arm at birth or postnatally - and adiposity outcomes - BMI, and skinfold thickness (triceps, biceps and subscapular) at birth or postnatally. Maternal vitamin D status in pregnancy did not influence infant birth outcomes, postnatal growth and adiposity outcomes in this cohort, perhaps due to the low prevalence (1·6 % of the cohort) of severe maternal vitamin D deficiency (defined as of <30·0 nmol/l) in our population.

  15. Chief Student Affairs Officers in 2-Year Colleges: Their Demographics and Educational Backgrounds

    ERIC Educational Resources Information Center

    Keim, Marybelle C.

    2008-01-01

    The purpose of this study was to determine demographics and educational backgrounds of chief student affairs officers (CSAOs) in public 2-year colleges. Using systematic sampling techniques, 300 2-year colleges were selected from the AACC Membership Directory for inclusion in the study. Each college's website was visited to determine the name of…

  16. Infantile Amnesia across the Years: A 2-Year Follow-Up of Children's Earliest Memories

    ERIC Educational Resources Information Center

    Peterson, Carole; Warren, Kelly L.; Short, Megan M.

    2011-01-01

    Although infantile amnesia has been investigated for many years in adults, only recently has it been investigated in children. This study was a 2-year follow-up and extension of an earlier study. Children (4-13 years old) were asked initially and 2 years later for their earliest 3 memories. At follow-up, their age at the time of these memories…

  17. B-type natriuretic peptide and high sensitive C-reactive protein predict 2-year all cause mortality in chest pain patients: a prospective observational study from Salta, Argentina

    PubMed Central

    2011-01-01

    Background Several mechanisms are involved in the pathophysiology of the Acute Coronary Syndrome (ACS). We have addressed whether B-type natriuretic peptide (BNP) and high-sensitive C-reactive protein (hsCRP) in admission samples may improve risk stratification in chest pain patients with suspected ACS. Methods We included 982 patients consecutively admitted with chest pain and suspected ACS at nine hospitals in Salta, Northern Argentina. Total and cardiac mortality were recorded during a 2-year follow up period. Patients were divided into quartiles according to BNP and hsCRP levels, respectively, and inter quartile differences in mortality were statistically evaluated applying univariate and multivariate analyses. Results 119 patients died, and the BNP and hsCRP levels were significantly higher among these patients than in survivors. In a multivariable Cox regression model for total death and cardiac death in all patients, the hazard ratio (HR) in the highest quartile (Q4) as compared to the lowest quartile (Q1) of BNP was 2.32 (95% confidence interval (CI), 1.24-4.35), p = 0.009 and 3.34 (95% CI, 1.26-8.85), p = 0.015, respectively. In the TnT positive patients (TnT > 0.01 ng/mL), the HR for total death and cardiac death in Q4 as compared to Q1 was 2.12 (95% CI, 1.07-4.18), p = 0.031 and 3.42 (95% CI, 1.13-10.32), p = 0.029, respectively. The HR for total death for hsCRP in Q4 as compared to Q1 was 1.97 (95% CI, 1.17-3.32), p = 0.011, but this biomarker did not predict cardiac death (p = 0.21). No prognostic impact of these two biomarkers was found in the TnT negative patients. Conclusion BNP and hsCRP may act as clinically useful biomarkers when obtained at admission in a population with suspected ACS. Trial Registration ClinicalTrials.gov Identifier: NCT01377402. PMID:21958326

  18. 41 CFR 101-5.104-6 - Conduct of feasibility studies.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... studies. 101-5.104-6 Section 101-5.104-6 Public Contracts and Property Management Federal Property... FEDERAL BUILDINGS AND COMPLEXES 5.1-General § 101-5.104-6 Conduct of feasibility studies. An initial... and detailed procedures to be followed in the conduct of each feasibility study. Arrangements will...

  19. 41 CFR 101-5.104-6 - Conduct of feasibility studies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... studies. 101-5.104-6 Section 101-5.104-6 Public Contracts and Property Management Federal Property... FEDERAL BUILDINGS AND COMPLEXES 5.1-General § 101-5.104-6 Conduct of feasibility studies. An initial... and detailed procedures to be followed in the conduct of each feasibility study. Arrangements will...

  20. 41 CFR 101-5.104-6 - Conduct of feasibility studies.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... studies. 101-5.104-6 Section 101-5.104-6 Public Contracts and Property Management Federal Property... FEDERAL BUILDINGS AND COMPLEXES 5.1-General § 101-5.104-6 Conduct of feasibility studies. An initial... and detailed procedures to be followed in the conduct of each feasibility study. Arrangements will...

  1. 41 CFR 101-5.104-6 - Conduct of feasibility studies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... studies. 101-5.104-6 Section 101-5.104-6 Public Contracts and Property Management Federal Property... FEDERAL BUILDINGS AND COMPLEXES 5.1-General § 101-5.104-6 Conduct of feasibility studies. An initial... and detailed procedures to be followed in the conduct of each feasibility study. Arrangements will...

  2. 21 CFR 312.120 - Foreign clinical studies not conducted under an IND.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., recording, analysis, and reporting of clinical trials in a way that provides assurance that the data and... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Foreign clinical studies not conducted under an....120 Foreign clinical studies not conducted under an IND. (a) Acceptance of studies. (1) FDA...

  3. 21 CFR 312.120 - Foreign clinical studies not conducted under an IND.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., recording, analysis, and reporting of clinical trials in a way that provides assurance that the data and... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Foreign clinical studies not conducted under an....120 Foreign clinical studies not conducted under an IND. (a) Acceptance of studies. (1) FDA...

  4. 21 CFR 312.120 - Foreign clinical studies not conducted under an IND.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., recording, analysis, and reporting of clinical trials in a way that provides assurance that the data and... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Foreign clinical studies not conducted under an....120 Foreign clinical studies not conducted under an IND. (a) Acceptance of studies. (1) FDA...

  5. 21 CFR 312.120 - Foreign clinical studies not conducted under an IND.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., recording, analysis, and reporting of clinical trials in a way that provides assurance that the data and... 21 Food and Drugs 5 2013-04-01 2013-04-01 false Foreign clinical studies not conducted under an....120 Foreign clinical studies not conducted under an IND. (a) Acceptance of studies. (1) FDA...

  6. A Collection of Studies Conducted in Education about "Global Warming" Problem

    ERIC Educational Resources Information Center

    Bozdogan, Aykut Emre

    2011-01-01

    The studies global warming problem conducted in education discipline in the world and in Turkey were analysed for this study. The literature was reviewed extensively especially through the articles in the indexed journals of Ebsco Host, Science Direct, Taylor and Francis and Web of Science databases and this study was conducted according to the…

  7. Langerhans cell histiocytosis in children under 2 years of age.

    PubMed

    Rivera-Luna, R; Alter-Molchadsky, N; Cardenas-Cardos, R; Martínez-Guerra, G

    1996-05-01

    This is a retrospective study of 55 children under the age of 2 years diagnosed with Langerhans cell histiocytosis (LCH). They were classified according to age and organ function and dysfunction following Lahey's criteria. The studied population was divided into four groups by age of diagnosis (0-6, 7-12, 13-18, and 19-24 months). Statistical analysis showed no significant difference in outcome between age groups, although the population under 6 months had a 81.3% fatality rate. The presence of organ dysfunction was a major cause of death in all age groups, being statistically significant in outcome (P > 0.005) compared with patients without organ dysfunction. The presence of thrombocytopenia and/or respiratory dysfunction was also highly associated with a fatal outcome. In the surviving population, no second malignancies have been reported. The late secondary effects of therapy include endocrine, orofacial, and osseous pathologies.

  8. Practical Issues of Conducting a Q Methodology Study: Lessons Learned From a Cross-cultural Study.

    PubMed

    Stone, Teresa Elizabeth; Maguire, Jane; Kang, Sook Jung; Cha, Chiyoung

    2016-12-06

    This article advances nursing research by presenting the methodological challenges experienced in conducting a multination Q-methodology study. This article critically analyzes the relevance of the methodology for cross-cultural and nursing research and the challenges that led to specific responses by the investigators. The use of focus groups with key stakeholders supplemented the Q-analysis results. The authors discuss practical issues and shared innovative approaches and provide best-practice suggestions on the use of this flexible methodology. Q methodology has the versatility to explore complexities of contemporary nursing practice and cross-cultural health research.

  9. 21 CFR 58.130 - Conduct of a nonclinical laboratory study.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Conduct of a nonclinical laboratory study. 58.130 Section 58.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL GOOD LABORATORY PRACTICE FOR NONCLINICAL LABORATORY STUDIES Protocol for and Conduct of...

  10. Conductivity study and fourier transform infrared (FTIR) characterization of methyl cellulose solid polymer electrolyte with sodium iodide conducting ion

    SciTech Connect

    Abiddin, Jamal Farghali Bin Zainal; Ahmad, Azizah Hanom

    2015-08-28

    Sodium ion (Na{sup +}) based solid polymer electrolyte (SPE) has been prepared using solution cast technique with distilled water as solvent and Methylcellulose (MC) as a polymer host. Methylcellulose polymer was chosen as the polymer host due to the abundance of lone pair electrons in the carbonyl and C-O-C constituents, which in turn provide multiple hopping sites for the Na{sup +} conducting ions. Variable compositions of sodium iodide (NaI) salt were prepared to investigate the optimum MC-NaI weight ratio. Results from Electrical Impedance Spectroscopy (EIS) technique show that pure methylcellulose has a low conductivity of 3.61 × 10{sup −11} S/cm.The conductivity increases as NaI content increases up to optimum NaIcomposition of 40 wt%, which yields an average conductivity of 2.70 × 10{sup −5} S/cm.

  11. Outcomes of childhood conduct problem trajectories in early adulthood: findings from the ALSPAC study.

    PubMed

    Kretschmer, Tina; Hickman, Matthew; Doerner, Rita; Emond, Alan; Lewis, Glyn; Macleod, John; Maughan, Barbara; Munafò, Marcus R; Heron, Jon

    2014-07-01

    Although conduct problems in childhood are stably associated with problem outcomes, not every child who presents with conduct problems is at risk. This study extends previous studies by testing whether childhood conduct problem trajectories are predictive of a wide range of other health and behavior problems in early adulthood using a general population sample. Based on 7,218 individuals from the Avon longitudinal study of parents and children, a three-step approach was used to model childhood conduct problem development and identify differences in early adult health and behavior problems. Childhood conduct problems were assessed on six occasions between age 4 and 13 and health and behavior outcomes were measured at age 18. Individuals who displayed early-onset persistent conduct problems throughout childhood were at greater risk for almost all forms of later problems. Individuals on the adolescent-onset conduct problem path consumed more tobacco and illegal drugs and engaged more often in risky sexual behavior than individuals without childhood conduct problems. Levels of health and behavior problems for individuals on the childhood-limited path were in between those for stable low and stable high trajectories. Childhood conduct problems are pervasive and substantially affect adjustment in early adulthood both in at-risk samples as shown in previous studies, but also in a general population sample. Knowing a child's developmental course can help to evaluate the risk for later maladjustment and be indicative of the need for early intervention.

  12. GUIDE FOR CONDUCTING TREATABILITY STUDIES UNDER CERCLA: THERMAL DESORPTION - INTERIM GUIDANCE

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the remedial investigation/feasibility study (RI/FS) process and the remedial design remedial action (RD/RA) process under the Comprehensive Environmental Response, Compensation, and Liab...

  13. GUIDE FOR CONDUCTING TREATABILITY STUDIES UNDER CERCLA: AEROBIC BIODEGRADATION REMEDY SCREENING

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the remedial investigation/feasibility study (KU FS) process and the remedial design/remedial action (RD/RA) process under the Comprehensive Environmental Response, Compensation, and L...

  14. Note: Optimization of the numerical data analysis for conductivity percolation studies of drying moist porous systems

    SciTech Connect

    Moscicki, J. K.; Sokolowska, D.; Dziob, D.; Nowak, J.; Kwiatkowski, L.

    2014-02-15

    A simplified data analysis protocol, for dielectric spectroscopy use to study conductivity percolation in dehydrating granular media is discussed. To enhance visibility of the protonic conductivity contribution to the dielectric loss spectrum, detrimental effects of either low-frequency dielectric relaxation or electrode polarization are removed. Use of the directly measurable monofrequency dielectric loss factor rather than estimated DC conductivity to parameterize the percolation transition substantially reduces the analysis work and time.

  15. Note: optimization of the numerical data analysis for conductivity percolation studies of drying moist porous systems.

    PubMed

    Moscicki, J K; Sokolowska, D; Kwiatkowski, L; Dziob, D; Nowak, J

    2014-02-01

    A simplified data analysis protocol, for dielectric spectroscopy use to study conductivity percolation in dehydrating granular media is discussed. To enhance visibility of the protonic conductivity contribution to the dielectric loss spectrum, detrimental effects of either low-frequency dielectric relaxation or electrode polarization are removed. Use of the directly measurable monofrequency dielectric loss factor rather than estimated DC conductivity to parameterize the percolation transition substantially reduces the analysis work and time.

  16. Medical Care and Your 1- to 2-Year-Old

    MedlinePlus

    ... Year-Old Medical Care and Your 1- to 2-Year-Old KidsHealth > For Parents > Medical Care and Your 1- to 2-Year-Old A A A The toddler months ... Following simple instructions? Saying a few words? Combining two words by age 2? The doctor may ask ...

  17. Neonates with extra-renal pelvis: the first 2 years.

    PubMed

    Katzir, Ze'ev; Witzling, Michaela; Nikolov, Gallina; Gvirtz, Gabriela; Arbel, Eliana; Kohelet, David; Boaz, Mona; Smetana, Shmuel; Lorberboym, Mordechai

    2005-06-01

    Extra-renal pelvis (ERpel) is a common ultrasonographic finding among neonates who have undergone recurrent ultrasound examinations for a better definition of prenatal renal pelvic dilatation. This study tries to determine whether or not ERpel has important prognostic implications. Seventy-nine neonates (17 female) were examined. All had a diagnosis of prenatal renal pelvis dilatation, which was shown by postnatal ultrasound to be ERpel. Sixty ERpel neonates were examined 1.5 months to 2.5 months after the ultrasound (US) diagnosis by both Tc-99m diethylene triamine penta-acetic acid (DPTA) dynamic renal scanning and (99m)Tc-pertechnetate direct cystography. Clinical assessment, urine cultures and renal ultrasound follow-up were maintained for 2 years. The proportion of urinary tract infections (UTIs) in patients with ERpel was compared with that of the total neonatal and infantile population with normal US scans in the region of our hospital. Associated minor congenital malformations were found in 12 of 79 neonates (15.2%). Four had a family history of ERpel. Among 60 neonates who underwent renal scanning, 36 (60%) were found to have urinary retention in the collecting system. Another nine (15%) had vesico-ureteral (VU) reflux, of which seven had urinary retention. Fifteen (25%) showed normal isotope imaging. Urinary tract infection was diagnosed in 16 ERpel neonates in whom only one exhibited VU reflux (grade 2). The incidence of neonatal UTI in the ERpel group was more than that of either neonatal or infantile UTI in those with normal US scans in the local population (20.2% vs 1.2% and 4.3%, respectively). Fifty-three infants completed a 2-year follow-up. Repeat renal ultrasonography indicated that one infant (1.8%) had developed bilateral hydronephrosis, 12 (22.6%) had unchanged findings, 18 (40%) showed an improvement (decrease of ERpel width or resolution in one side) and, in 22 (41.5%) infants, the condition had resolved. No clinical or kidney function

  18. Conducting Real-Time Videofluoroscopic Swallow Study via Telepractice: A Preliminary Feasibility and Reliability Study.

    PubMed

    Burns, Clare L; Ward, Elizabeth C; Hill, Anne J; Phillips, Nick; Porter, Linda

    2016-06-01

    A small number of studies have examined the feasibility of conducting videofluoroscopic swallow studies (VFSS) via telepractice. While the results have confirmed this potential, the systems tested to date have either reported issues that impacted the ability to analyze/interpret the VFSS recordings in real time, or they were not designed to enable real-time interpretation. Further system design is needed to establish a telepractice model that enables the VFSS assessment to be both guided and interpreted live in real time. The aim of this study was to test the feasibility and reliability of using a telepractice system to enable live VFSS assessment. Twenty adult patients underwent a VFSS assessment directed by a telepractice SLP with competency in VFSS located in another room of the hospital. The telepractice clinician led the sessions using a C20 Cisco TelePresence System. This was linked in real time via a secure telehealth network (at 4 megabits per second (Mbit/s)) to a C60 Cisco TelePresence System located in a fluoroscopy suite, connected to the digital fluoroscopy system. Levels of agreement were calculated between the telepractice clinician and a face-to-face clinician who simultaneously rated the VFSS in real time. High levels of agreement for swallowing parameters (range = 75-100 %; k = -0.34 to 1.0) and management decisions (range = 70-100 %, k = 0.64-1.0) were found. A post-session questionnaire revealed clinicians agreed that the telepractice system enabled successful remote assessment of VFSS. The findings support the potential to conduct live VFSS assessment via a telepractice model.

  19. "Conducting Is Everywhere!" A Case Study of the Development of Preservice Music Teacher Occupational Identity in a Beginning Conducting Course

    ERIC Educational Resources Information Center

    Johnson, Erik

    2014-01-01

    Research on pre-service music teacher occupational identity often highlights two competing identities: performer and teacher (L'Roy, 1983; Roberts, 1991; Pellegrino, 2009). Of the many factors that contribute to the occupational identity of the pre-service music teacher (Woodford, 2002), conducting has the potential to integrate performer and…

  20. Bias-dependent conductive characteristics of individual GeSi quantum dots studied by conductive atomic force microscopy.

    PubMed

    Wu, R; Zhang, S L; Lin, J H; Jiang, Z M; Yang, X J

    2011-03-04

    The bias-dependent electrical characteristics of individual self-assembled GeSi quantum dots (QDs) are investigated by conductive atomic force microscopy. The results reveal that the conductive characteristics of QDs are strongly influenced by the applied bias. At low (-0.5 to - 2.0 V) and high (-2.5 to - 4.0 V) biases, the current distributions of individual GeSi QDs exhibit ring-like and disc-like characteristics respectively. The current of the QD's central part increases more quickly than that of the other parts as the bias magnitude increases. Histograms of the magnitude of the current on a number of QDs exhibit the same single-peak feature at low biases, and double- or three-peak features at high biases, where additional peaks appear at large-current locations. On the other hand, histograms of the magnitude of the current on the wetting layers exhibit the same single-peak feature for all biases. This indicates the conductive mechanism is significantly different for QDs and wetting layers. While the small-current peak of QDs can be attributed to the Fowler-Nordheim tunneling model at low biases and the Schottky emission model at high biases respectively, the large-current peak(s) may be attributed to the discrete energy levels of QDs. The results suggest the conductive mechanisms of GeSi QDs can be regulated by the applied bias.

  1. Latent rheumatic heart disease: outcomes 2 years after echocardiographic detection.

    PubMed

    Beaton, Andrea; Okello, Emmy; Aliku, Twalib; Lubega, Sulaiman; Lwabi, Peter; Mondo, Charles; McCarter, Robert; Sable, Craig

    2014-10-01

    Screening with portable echocardiography has uncovered a large burden of latent rheumatic heart disease (RHD) among asymptomatic children in endemic regions, the significance of which remains unclear. This study aimed to determine the 2-year outcomes for children with latent RHD diagnosed by echocardiographic screening. Children identified with latent RHD enrolled in a biannual follow-up program. Risk factors for disease persistence and progression were examined. Of 62 children, 51 (82 %) with latent RHD had a median follow-up period of 25 months. Of these 51 children, 17 (33.3 %) reported an interval sore throat or symptoms consistent with acute rheumatic fever (ARF). Of 43 children initially classified as having borderline RHD, 21 (49 %) remained stable, 18 (42 %) improved (to no RHD) and 4 (10 %) worsened to definite RHD. Of the 8 children initially classified as having definite RHD, 6 (75 %) remained stable, and 2 (25 %) improved to borderline RHD. Two children had confirmed episodes of recurrent ARF, one of which represented the sole case of clinical worsening. The risk factors for disease persistence or progression included younger age (p = 0.05), higher antistreptolysin O titers at diagnosis (p = 0.05), and more morphologic valve abnormalities (p = 0.01). After 2 years, most of the children had a benign course, with 91 % remaining stable or showing improvement. Education may improve recognition of streptococcal sore throat. Longer-term follow-up evaluation, however, is warranted to confirm disease progression and risk factor profile. This could help tailor screening protocols for those at highest risk.

  2. First-Year Students' Expectations of Conduct and Consequence: A Case Study

    ERIC Educational Resources Information Center

    Crance Gutmann, Gina-Lyn

    2008-01-01

    Research on first-year students' expectations about college has explored areas of academic and social expectations, but not first-year college students' expectations about judicial conduct and consequence. The purpose of this study was to empirically explore two questions: what are first year students' expectations about campus conduct and…

  3. The effects of dutasteride, tamsulosin, and the combination on storage and voiding in men with benign prostatic hyperplasia and prostatic enlargement: 2-year results from the Combination of Avodart and Tamsulosin study.

    PubMed

    Becher, E; Roehrborn, C G; Siami, P; Gagnier, R P; Wilson, T H; Montorsi, F

    2009-01-01

    This article reports the results of a post hoc analysis of the multicenter, randomized, double-blind Combination of Avodart and Tamsulosin (CombAT) study, which aimed to investigate the effects of dutasteride (0.5 mg), tamsulosin (0.4 mg), and their combination on storage and voiding symptoms in 4844 men aged > or =50 years with moderate-to-severe lower urinary tract symptoms (International Prostate Symptom Score > or =12), prostate volume (PV) > or =30 cm(3) and PSA 1.5-10 ng ml(-1). After 24 months, combination treatment achieved significantly greater mean reductions in both voiding and storage symptoms than either monotherapy, in each of the three baseline PV tertiles (30 to <42, 42 to <58, > or =58 cm(3)). Dutasteride was as effective as tamsulosin for control of storage symptoms, but provided significantly greater relief of voiding symptoms than tamsulosin.

  4. Assessing the efficacy of 2 years of maintenance treatment with venlafaxine extended release 75–225 mg/day in patients with recurrent major depression: a secondary analysis of data from the PREVENT study

    PubMed Central

    Kornstein, Susan G.; Kocsis, James H.; Ahmed, Saeeduddin; Thase, Michael; Friedman, Edward S.; Dunlop, Boadie W.; Yan, Bing; Pedersen, Ron; Ninan, Philip T.; Li, Thomas; Keller, Martin

    2013-01-01

    The objective of this study was to evaluate the long-term efficacy of venlafaxine extended release (ER) ≤225 mg/ day in patients with recurrent major depressive disorder (MDD). In this double-blind trial, outpatients with recurrent MDD (N=1096) were randomized to 10 weeks of acute-phase treatment with venlafaxine ER (75–300 mg/ day) or fluoxetine (20–60 mg/day) followed by a 6-month continuation phase and two consecutive 12-month maintenance phases. At the start of each maintenance period, venlafaxine ER responders were randomized to double-blind venlafaxine ER or placebo. In this analysis, data from responders to acute and continuation treatment were analyzed during the combined maintenance phases while receiving venlafaxine ER ≤225 mg/day. Failure to maintain response was defined as an increase in maintenance dose to 300 mg/day or recurrence. Differences were calculated using Kaplan–Meier methods and compared using log-rank tests. Continuation-phase responders (n =114) receiving venlafaxine ER ≤225 mg/ day comprised the analysis population (venlafaxine ER: n= 55; placebo: n= 59). The estimated probability for remaining well across 24 months of maintenance treatment was 67% for venlafaxine ER and 41% for placebo (P = 0.007). Venlafaxine ER effectively maintained response at doses ≤225 mg/day for up to 2.5 years in patients with recurrent MDD. The findings are consistent with those of the full data set. PMID:18854724

  5. Latino Community-Based Participatory Research Studies: A Model for Conducting Bilingual Translations

    PubMed Central

    Sánchez-Johnsen, Lisa; Escamilla, Julia; Rodriguez, Erin M.; Vega, Susan; Bolaños, Liliana

    2015-01-01

    Many behavioral health materials have not been translated into Spanish. Of those that are available in Spanish, some of them have not been translated correctly, many are only appropriate for a subgroup of Latinos, and/or multiple versions of the same materials exist. This article describes an innovative model of conducting bilingual English–Spanish translations as part of community-based participatory research studies and provides recommendations based on this model. In this article, the traditional process of conducting bilingual translations is reviewed, and an innovative model for conducting translations in collaboration with community partners is described. Finally, recommendations for conducting future health research studies with community partners are provided. Researchers, health care providers, educators, and community partners will benefit from learning about this innovative model that helps produce materials that are more culturally appropriate than those that are produced with the most commonly used method of conducting translations. PMID:25741929

  6. Electrochemical, In Situ Raman Spectroscopic, and Conductivity Studies of Polypyrrole Incorporating Large Size Anions: Conducting Nature of Reduced Form

    DTIC Science & Technology

    1990-05-21

    oxidized (conducting) and reduced (nonconducting).I On the other hand, in our previous report a Pry thin-film incorporating copper phthalocyanine ...tetrasulfonates (PPy-MPcTs), copper phthalocyanine monosulfonate (PPy-CuPcS), copper porpyrin tetrasulfonate (PPy-CuPrTs), and a couple of anionic...Acetonitrile (MeCN) was purified by the method reported by Forcier and Olver.14 The copper phthalocyanine -3,4’,4’’,4’’’-tetrasulfonic acid tetrasodium

  7. 21 CFR 58.130 - Conduct of a nonclinical laboratory study.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... GENERAL GOOD LABORATORY PRACTICE FOR NONCLINICAL LABORATORY STUDIES Protocol for and Conduct of a... date of collection. This information shall be located on the specimen container or shall accompany...

  8. Preliminary study on improvement of cementitious grout thermal conductivity for geothermal heat pump applications

    SciTech Connect

    Allan, M.L.

    1996-06-01

    Preliminary studies were preformed to determine whether thermal conductivity of cementitious grouts used to backfill heat exchanger loops for geothermal heat pumps could be improved, thus improving efficiency. Grouts containing selected additives were compares with conventional bentonite and cement grouts. Significant enhancement of grout alumina grit, steel fibers, and silicon carbide increased the thermal conductivity when compared to unfilled, high solids bentonite grouts and conventional cement grouts. Furthermore, the developed grouts retained high thermal conductivity in the dry state, where as conventional bentonite and cement grouts tend to act as insulators if moisture is lost. The cementitious grouts studied can be mixed and placed using conventional grouting equipment.

  9. 75 FR 77958 - Gravesite Reservation Survey (2 Year); Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF VETERANS AFFAIRS Gravesite Reservation Survey (2 Year); Correction AGENCY: National Cemetery Administration, Department of Veterans Affairs. ACTION: Notice; correction. SUMMARY: The Department of Veterans Affairs...

  10. Prevalence and comorbidity of eating disorders among a community sample of adolescents: 2-year follow-up.

    PubMed

    Rojo-Moreno, Luis; Arribas, Pilar; Plumed, Javier; Gimeno, Natalia; García-Blanco, Ana; Vaz-Leal, Francisco; Luisa Vila, María; Livianos, Lorenzo

    2015-05-30

    The previous literature about comorbidity between eating disorders (ED) and other DSM-IV psychiatric disorders in adolescence has employed cross-sectional studies with clinical samples, where the comorbid disorders were diagnosed retrospectively. The present study aims to overcome these limitations by the analysis of comorbidity in a community population during 2-year follow-up. A semi-structured interview was applied to a teenager sample. Firstly, a cross-sectional and non-randomized study on psychiatric morbidity was conducted with 993 teenagers between the ages of 12 and 16 from five schools. Secondly, 326 students between 14 and 17 years old of one school were reassessed 2 years later in order to detect ED new cases and find associations with previous psychiatric disorders. The ED prevalence was 3.6%. Cross-sectional analysis revealed that 62.9% of individuals with an ED had comorbid disorders: anxiety disorders (51.4%), Attention Deficit Hyperactivity Disorder (31.4%), oppositional defiant disorder (11.4%), and obsessive compulsive disorder (8.6%). Prospective longitudinal analysis showed an ED incidence rate of 2.76% over the course of 2 years. 22.2% of new cases had received previous psychiatric diagnoses, of which all were anxiety disorders. Thus, ED exhibited a high comorbidity rate among adolescent populations and anxiety disorders were the most common comorbid diagnosis.

  11. Developmental Associations Between Conduct Problems and Expressive Language in Early Childhood: A Population-Based Study.

    PubMed

    Girard, Lisa-Christine; Pingault, Jean-Baptiste; Doyle, Orla; Falissard, Bruno; Tremblay, Richard E

    2016-08-01

    Conduct problems have been associated with poor language development, however the direction of this association in early childhood remains unclear. This study examined the longitudinal directional associations between conduct problems and expressive language ability. Children enrolled in the UK Millennium Cohort Study (N = 14, 004; 50.3 % boys) were assessed at 3 and 5 years of age. Parent reports of conduct problems and standardised assessments of expressive language were analyzed using cross-lagged modeling. Conduct problems at 3 years was associated with poorer expressive language at 5 years and poorer expressive language at 3 years was associated with increased conduct problems by 5 years. The results support reciprocal associations, rather than a specific unidirectional path, which is commonly found with samples of older children. The emergence of problems in either domain can thus negatively impact upon the other over time, albeit the effects were modest. Studies examining the effects of intervention targeting conduct problems and language acquisition prior to school entry may be warranted in testing the efficacy of prevention programmes related to conduct problems and poor language ability early in childhood.

  12. Diameter Dependence of Lattice Thermal Conductivity of Single-Walled Carbon Nanotubes: Study from Ab Initio.

    PubMed

    Yue, Sheng-Ying; Ouyang, Tao; Hu, Ming

    2015-10-22

    The effects of temperature, tube length, defects, and surface functionalization on the thermal conductivity (κ) of single-walled carbon nanotubes (SWCNTs) were well documented in literature. However, diameter dependence of thermal conductivity of SWCNTs received less attentions. So far, diverse trends of the diameter dependence have been discussed by different methods and all the previous results were based on empirical interatomic potentials. In this paper, we emphasize to clarify accurate κ values of SWCNTs with different diameters and in-plane κ of graphene. All the studies were under the framework of anharmonic lattice dynamics and Boltzmann transport equation (BTE) based on first principle calculations. We try to infer the right trend of diameter dependent thermal conductivity of SWCNTs. We infer that graphene is the limitation as SWCNT with an infinite diameter. We analyzed the thermal conductivity contributions from each phonon mode in SWCNTs to explain the trend. Meanwhile, we also identify the extremely low thermal conductivity of ultra-thin SWCNTs.

  13. The Relationship between Nerve Conduction Study and Clinical Grading of Carpal Tunnel Syndrome

    PubMed Central

    Cheluvaiah, Janardhan D.; Agadi, Jagadish B.; Nagaraj, Karthik

    2016-01-01

    Introduction Carpal Tunnel Syndrome (CTS) is the most common nerve entrapment. Subjective sensory symptoms are common place in patients with CTS, but sometimes they are not supported by objective findings in the neurological examination. Electrodiagnostic (EDx) studies are a valid and reliable means of confirming the diagnosis. The amplitudes along with the conduction velocities of the sensory nerve action potential and motor nerve action potential reflect the functional state of axons, and are useful parameters and complement the clinical grading in the assessment of severity of CTS. Aim To conduct median nerve sensory and motor conduction studies on patients with carpal tunnel syndrome and correlate the relationship between nerve conduction study parameters and the clinical severity grading. Materials and Methods Based on clinical assessment, the study patients were divided into 03 groups with mild CTS, moderate CTS and severe CTS respectively as per Mackinnson’s classification. Median and ulnar nerve conduction studies were performed on bilateral upper limbs of 50 patients with symptoms of CTS and 50 age and sex matched healthy control subjects. The relationship between the clinical severity grade and various nerve conduction study parameters were correlated. Results In this prospective case control study, 50 patients with symptoms consistent with CTS and 50 age and sex matched healthy control subjects were examined over a 10 month period. A total of 30 patients had unilateral CTS (right upper limb in 19 and left upper limb in 11) and 20 patients had bilateral CTS. Female to male ratio was 3.54 to 1. Age ranged from 25 to 81 years. The mean age at presentation was 49.68±11.7 years. Tingling paresthesias of hand and first three fingers were the most frequent symptoms 48 (98%). Tinel’s and Phalen’s sign were positive in 36 (72%) and 44 (88%) patients respectively. The mean duration of symptoms at presentation was 52.68±99.81 weeks. 16 patients (32%) had

  14. Photoconductivity, low-temperature conductivity, and magnetoresistance studies on the layered semiconductor GaTe

    SciTech Connect

    Bose, D. N.; Pal, Sarbari

    2001-06-15

    Single crystals of p-GaTe were grown by the Bridgman technique and characterized through x-ray diffraction, energy-dispersive x-ray analysis, x-ray photoemission spectroscopy, and transmission electron microscopy studies. The photoconductivity spectral response for in-plane conduction showed a peak at 747 nm (1.66 eV). Photoconductivity gain was determined in two orthogonal directions from which the majority carrier (hole) lifetimes were found to be 3.43{times}10{sup {minus}7} and 2.03{times}10{sup {minus}6}s, respectively, parallel and perpendicular to the layer planes. Studies of the temperature dependence of conductivity in the directions along and perpendicular to the layer planes were carried out between 10 and 80 K. Along the layer planes the conductance G{sub {parallel}} varied as lnT between 12 and 20 K, characteristic of weak localization, while between 20 and 50 K the conductivity {sigma}{sub {parallel}} varied as T{sup 1/2}. In the perpendicular direction the conductance G{sub {perpendicular}} varied as exp(T/T{sub 0}){sup 1/3} between 9 and 20 K and the conductivity {sigma}{sub {perpendicular}} varied as exp(T/T{sub 0}){sup 1/4} between 20 and 50 K, characteristic of hopping conduction in two and three dimensions, respectively. Negative transverse magnetoresistance was observed at 10 K for conduction in both directions for magnetic fields H{lt}0.4T, the increase in conductance being found to be proportional to H{sup 2}. Band conduction with positive magnetoresistance was observed for both current directions at T{gt}70K. The I-V characteristics at 10 K showed quantized behavior due to electron tunneling across potential barriers caused by stacking faults between layer planes.

  15. A general population twin study of conduct problems and the auditory P300 waveform.

    PubMed

    Bertoletti, Eleonora; Michelini, Giorgia; Moruzzi, Sara; Ferrer, Giuseppina; Ferini-Strambi, Luigi; Stazi, Maria Antonietta; Ogliari, Anna; Battaglia, Marco

    2014-01-01

    Reduced amplitude of the P300 event-related potential has been consistently associated with a variety of externalising problems, including conduct disorder. The few available genetically-informative studies of these relationships, however, were conducted among adolescents/adults (i.e., at an age when conduct disorder has typically already become manifest). Among 200 general population twins with a mean age of 9 years (range 6-14 years), we studied the relationship between the P300 waveform elicited by an auditory oddball task and the DSM-oriented conduct problems scale of the Child Behavior Checklist 6-18. Conduct problems scores were negatively and significantly correlated (r = -0.19, p = 0.01) with P300 amplitude; correlations between P300 amplitude and the other DSM-oriented Child Behavior Checklist scales were non-significant, except for oppositional defiant problems (p = 0.01). We found moderate heritability estimates for both P300 amplitude (0.58, CI:0.37;0.73) and conduct problems (0.52, CI:0.25;0.70). Bivariate twin analyses indicated that the covariation between these two phenotypes can be explained by additive genetic factors only, with a genetic correlation of -0.33. An association between reduced P300 amplitude and conduct problems can be substantiated already in childhood, at an age that precedes the most typical onset of conduct disorder. This relationship appears to be genetic in nature. Reduced P300 amplitude can represent a valuable marker for conduct problems, and can contribute to the early identification of children at high-risk for conduct disorder.

  16. Shock wave over hand muscles: a neurophysiological study on peripheral conduction nerves in normal subjects

    PubMed Central

    Manganotti, Paolo; Amelio, Ernesto; Guerra, Claudio

    2012-01-01

    Summary Background and purpose: shock waves are defined as a sequence of single sonic pulses largely used in the treatment of bone and tendon diseases and recently on muscular hypertonia in stroke patients. Our purpose is to investigate the short and long term effect of extra-corporeal shock wave therapy (ESWT) on the peripheral nerve conduction and central conductions from the treated muscles in normal human subjects in order to define safety criteria. Methods: we studied 10 patients normal subjects. Motor and sensory nerve conduction velocity and F response from right ipothenar eminence (abductor digiti minimi) of the hand was recorded. Furthermore MEP latency and amplitude and central conduction from the same muscles by transcranial magnetic stimulation was evaluated. In all subjects each neurophysiological measures were monitored before, immediately after, 15 minutes and after 30 minutes from the active ESWT treatment (1600 shots with an energy applied of 0.030 mj/mm2). Results: no significant short or long term changes were noted in sensory and motor peripheral nerve conduction and in central motor conduction in all the subjects evaluated after ESWT. Conclusions: the ESWT has no effect on sensory and motor peripheral nerve conduction and in central motor conduction. The ESWT using low level of energy represent a safety method for treating the muscles in human subjects without involvement of motor or sensory nervous trunks. Different mechanisms of action of ESWT are discussed. PMID:23738282

  17. An Assessment of Treatment Integrity in Behavioral Intervention Studies Conducted with Persons with Mental Retardation

    ERIC Educational Resources Information Center

    Wheeler, John J.; Mayton, Michael R.; Carter, Stacy L.; Chitiyo, Morgan; Menendez, Anthony L.; Huang, Ann

    2009-01-01

    The purpose of this study was to assess the degree to which behavioral intervention studies conducted with persons with mental retardation operationally defined the independent variables and evaluated and reported measures of treatment integrity. The study expands the previous work in this area reported by Gresham, Gansle, and Noell (1993) and…

  18. Vapor sensing mechanism of acid on copper phthalocyanine thin films studied by electrical conductivity

    NASA Astrophysics Data System (ADS)

    Singh, Sukhwinder; Saini, G. S. S.; Tripathi, S. K.

    2013-06-01

    The electrical conductivity of thin films of iron phthalocyanine on glass substrates by thermal evaporation technique have been investigated. The electrical conductivity of thin films of these complexes changes when exposed to oxidizing and reducing gases such as halogens, ammonia, water and NOX. Thermal activation energy in the intrinsic region and impurity scattering region can be calculated by using Arrhenius plot. The dark conductivity and photoconductivity have been taken at different temperatures in the range 312-389 K. These films have been studied as chemical sensors for dilute sulphuric acid.

  19. Clinical Features and Treatment Outcomes of Primary Immune Thrombocytopenic Purpura in Hospitalized Children Under 2-Years Old

    PubMed Central

    Farhangi, H; Ghasemi, A; Banihashem, A; Badiei, Z; Jarahi, L; Eslami, G; Langaee, T

    2016-01-01

    Background Immune thrombocytopenic purpura (ITP) is the most prevalent cause of thrombocytopenia in children. Despite the importance of ITP in children under 2-years old, only a few publications are available in the literature.ITP usually presents itself as isolated thrombocytopenia and mucocutaneous bleeding. Materials and Methods This study was conducted on 187 under 2-year-old children diagnosed with ITP and treated at Dr. Sheikh Hospital from 2004 to 2011.In this retrospective study, clinical symptoms, laboratory findings, history of viral infections, vaccination history, and treatment efficacy in children under 2-years old with ITP were investigated.Patients were followed for one year after being discharged from the hospital. Results The risk of the disease developing into chronic form was higher in older children (0.001). ITP in children under 3-months old was significantly associated with vaccination (p=0.007). There was no significant differences between male and female patients in regards to newly diagnosed ITP, persistent, and chronic disease status (p = 0.21). No significant difference in bleeding symptoms was observed between patients under 3-months old and 3 to 24-months old (p=0.18). Conclusion Infantile ITP respond favorably to treatment. The risk of the disease developing into chronic form is higher in 3-to-24-month-old children compared to under-three-month olds. PMID:27222699

  20. Cost and Schedule Analytical Techniques Development: Option 2 Year

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This Final Report summarizes the activities performed by Science Applications International Corporation (SAIC) for the Option 2 Year from December 1, 1996 through November 30, 1997. The Final Report is in compliance with Paragraph 5 of Section F of the contract. This CSATD contract provides products and deliverable in the form of models, data bases, methodologies, studies and analyses for the NASA Marshall Space Flight Center's (MSFC) Engineering Cost Office (PPO3) the Program Plans and Requirements Officer (PP02), and other user organizations. Detailed Monthly Progress reports were submitted to MSFC in accordance with the contract's Statement of Work, Section TV "Reporting and Documentation". These reports spelled out each month's specific work accomplishments, deliverables submitted, major meetings held, and other pertinent information. This Final Report will summarize these activities at higher level. During this contract Option Year, SAIC expended 29,830 man-hours in tile performance of tasks called out in the Statement of Work and reported oil in this yearly Final Report. This represents approximately 16 full-time EPs. Included are the basis Huntsville-based team, plus SAIC specialists in San Diego, Ames Research Center, Chicago, and Colorado Springs performing specific tasks for which they are uniquely qualified.

  1. Conductivity Studies of Plasticized-poly(methylmethacrylate) (PMMA) Polymer Electrolytes Films

    NASA Astrophysics Data System (ADS)

    Ahmad, A.; Isa, K. B. Md; Othman, L.; Osman, Z.

    2008-05-01

    In the present study, five systems of samples have been prepared by the solution casting technique. Polymethylmethacrylate (PMMA) is used as a based polymer. Ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. The salt that was selected for this study is lithium triflate (LiCF3SO3). The pure PMMA sample is taken as a reference. The five systems are the (PMMA-EC) system, the (PMMA-PC) system, the (PMMA-LiCF3SO3) system, the ([PMMA-EC]-LiCF3SO3) system and the ([PMMA-PC]-LiCF3SO3) system. The conductivity for each system is characterized using impedance spectroscopy. The conductivity of the pure PMMA, the (PMMA-EC) system and the (PMMA-PC) system at room temperature is 2.37×10-9 Scm-1, 3.63×10-8 Scm-1 and 4.18×10-8 Scm-1 respectively. On addition of salt in the (PMMA-LiCF3SO3) system, the conductivity is increased by two orders of magnitude. The conductivity for the ([PMMA-EC]-LiCF3SO3) system and the ([PMMA-PC]-LiCF3SO3) system is 3.54×10-5 Scm-1 and 2.06×10-5 Scm-1 respectively. The conductivity temperature-dependence studies are then performed on the highest conducting film from the (PMMA-LiCF3SO3) system, the ([PMMA—EC]-LiCF3SO3) system and the (PMMA-PC]-LiCF3SO3) system. The conductivity temperature studies are conducted in the temperature range between 303 K and 373 K. The result shows that the conductivity is increased as the temperature increased. The increase of conductivity is due to the increase in number of mobile ions. It shows that the conductivity for all of these systems obeys Arrhenius rule where it indicates that the points lie in an almost straight line. The activation energy, Ea for the (PMMA-35wt % LiCF3SO3) system, the ([PMMA-EC]-35wt % LiCF3SO3) system and the ([PMMA-PC]-35wt % LiCF3SO3) system is 0.21 eV, 0.10 eV and 0.15 eV respectively.

  2. Effect of extracellular potassium accumulation on muscle fiber conduction velocity: a simulation study.

    PubMed

    Fortune, Emma; Lowery, Madeleine M

    2009-10-01

    A progressive reduction in muscle fiber conduction velocity is typically observed during fatiguing muscle contraction. Although the exact causes of the conduction velocity decrease have not yet been fully established, increasing evidence suggests that changes in extracellular potassium concentration may be largely responsible. In this study, a mathematical model was developed to examine the effect of extracellular potassium concentration on the muscle fiber action potential and conduction velocity. The model was used to simulate changes in extracellular potassium concentration at a range of temperatures and extracellular potassium accumulation during repetitive stimulation of the muscle fiber at 37 degrees C. The action potential broadened, and its amplitude and conduction velocity decreased as extracellular potassium concentration increased. The potassium-induced changes in action potential shape and conduction velocity were eliminated when the inward rectifier channels were removed from the model. The results support the hypothesis that accumulation of extracellular potassium ions may be a major contributor to the reduction in muscle fiber conduction velocity and loss of membrane excitability during fatiguing contractions. They additionally suggest that inward rectifier currents play a critical role in potassium-induced membrane depolarization, leading to increased sodium inactivation and resulting in the observed reduction in conduction velocity and membrane excitability.

  3. Experimental and theoretical study of AC electrical conduction mechanisms of semicrystalline parylene C thin films.

    PubMed

    Kahouli, Abdelkader; Sylvestre, Alain; Jomni, Fethi; Yangui, Béchir; Legrand, Julien

    2012-01-26

    The electrical conduction mechanisms of semicrystalline thermoplastic parylene C (-H(2)C-C(6)H(3)Cl-CH(2)-)(n) thin films were studied in large temperature and frequency regions. The alternative current (AC) electrical conduction in parylene C is governed by two processes which can be ascribed to a hopping transport mechanism: correlated barrier hopping (CBH) model at low [77-155 K] and high [473-533 K] temperature and the small polaron tunneling mechanism (SPTM) from 193 to 413 K within the framework of the universal law of dielectric response. The conduction mechanism is explained with the help of Elliot's theory, and the Elliot's parameters are determined. From frequency- and temperature-conductivity characteristics, the activation energy is found to be 1.27 eV for direct current (DC) conduction interpreted in terms of ionic conduction mechanism. The power law dependence of AC conductivity is interpreted in terms of electron hopping with a density N(E(F)) (~10(18) eV cm(-3)) over a 0.023-0.03 eV high barrier across a distance of 1.46-1.54 Å.

  4. Formal feasibility studies in palliative care: why they are important and how to conduct them.

    PubMed

    Hagen, Neil A; Biondo, Patricia D; Brasher, Penny M A; Stiles, Carla R

    2011-08-01

    The concept of clinical trial feasibility is of great interest to the community of palliative care researchers, clinicians, and granting agencies. Significant allocation of resources is required in the form of funding, time, intellect, and motivation to carry out clinical research, and understandably, clinical investigators, institutions, and granting agencies are disappointed when funded trials are unsuccessfully conducted. We argue that for many trials conducted in palliative care, the feasibility of conducting the proposed trial should be formally explored before implementation. There is substantial information available within the literature on the topic of study feasibility but no singular guide on how one can pragmatically apply this advice in the palliative care setting. We suggest that a Formal Feasibility Study for palliative care trials should be commonly conducted before development of a larger pivotal trial, to prospectively identify barriers to research, develop strategies to address these barriers, and predict whether the larger study is feasible. If a Formal Feasibility Study is not required, elements of feasibility can be specifically tested before launching clinical trials. The purpose of this article is to offer a draft framework for the design and conduct of a Formal Feasibility Study that, if implemented, could concretely support successful completion of high-quality research in a timely fashion. Additionally, we hope to foster dialogue within the palliative care research community regarding the relevance of establishing feasibility before initiation of definitive trials in the palliative care population.

  5. Methodological, Theoretical, Infrastructural, and Design Issues in Conducting Good Outcome Studies

    ERIC Educational Resources Information Center

    Kelly, Michael P.; Moore, Tessa A.

    2011-01-01

    This article outlines a set of methodological, theoretical, and other issues relating to the conduct of good outcome studies. The article begins by considering the contribution of evidence-based medicine to the methodology of outcome research. The lessons which can be applied in outcome studies in nonmedical settings are described. The article…

  6. Study of the Kinetics of an S[subscript N]1 Reaction by Conductivity Measurement

    ERIC Educational Resources Information Center

    Marzluff, Elaine M.; Crawford, Mary A.; Reynolds, Helen

    2011-01-01

    Substitution reactions, a central part of organic chemistry, provide a model system in physical chemistry to study reaction rates and mechanisms. Here, the use of inexpensive and readily available commercial conductivity probes coupled with computer data acquisition for the study of the temperature and solvent dependence of the solvolysis of…

  7. GUIDE FOR CONDUCTING TREATABILITY STUDIES UNDER CERCLA: SOLVENT EXTRACTION - INTERIM GUIDANCE

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the remedial investigation/feasibility study (RI/FS) process and the remedial design/remedial action (RD/RA) process under the Comprehensive Environmental Response, Compensation and Liabi...

  8. 42 CFR 90.8 - Conduct of health assessments and health effects studies.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Conduct of health assessments and health effects studies. 90.8 Section 90.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES HEALTH ASSESSMENTS AND HEALTH EFFECTS STUDIES OF HAZARDOUS SUBSTANCES RELEASES AND...

  9. 42 CFR 90.8 - Conduct of health assessments and health effects studies.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Conduct of health assessments and health effects studies. 90.8 Section 90.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES HEALTH ASSESSMENTS AND HEALTH EFFECTS STUDIES OF HAZARDOUS SUBSTANCES RELEASES AND...

  10. GUIDE TO CONDUCTING TREATABILITY STUDIES UNDER CERCLA: SOIL WASHING - INTERIM GUIDANCE

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the remedial investigation/feasibility study (RI/FS) process and the remedial design/remedial action (RD/RA) process under the Comprehensive Environmental Response, Compensation, and Liab...

  11. Dielectric and ac conductivity studies of ZnO/Eu3+: Titanosilicate matrix

    NASA Astrophysics Data System (ADS)

    Arun Kumar, K. V.; Sunil, Thomas; Ann Mary, K. A.; Cyriac, Joseph; Biju, P. R.; Unnikrishnan, N. V.

    2014-01-01

    ZnO nanoparticles /Eu3+ doped SiO2-TiO2 matrices were synthesized through sol-gel route. Structural and dielectric properties of ZnO nanocrystallites co-doped with Eu3+ in SiO2-TiO2 matrices were presented. The HRTEM and XRD measurements confirm the presence of ZnO nanocrystallites. The dielectric and electrical conductivity studies of the samples are completed for a frequency of 100 Hz to 2 MHz. The conductivity variation with the ZnO content in the Eu3+ doped SiO2-TiO2 system were explained by correlating the presence of ionic contribution to the electrical conductivity process. From the frequency dependence of dielectric constant and conductivity, the Cole-Cole parameters and power law parameters were evaluated. The dielectric relaxation phenomena were investigated using the dielectric moduli formulation.

  12. A preliminary study on the thermal conductivity and flammability of WPC based on some tropical woods

    NASA Astrophysics Data System (ADS)

    Chia, L. H. L.; Chua, P. H.; Lee, E. E. N.

    Selected local woods and their wood-polymer combinations or composites (WPC) were tested for their thermal conductivity and their fire resistance. WPC were prepared by polymerizing monomers " in situ" in oven dried woods by gamma radiation. The monomers included acrylonitrile (AN), 60% styrene-40% acrylonitrile (STAN), methyl methacrylate (MMA), 95% methyl methacrylate —5% dioxane (MD), and vinylidene chloride (VDC). A reduction in thermal conductivity was exhibited by all the composites prepared. W-PAN showed the greatest reduction in thermal conductivity and W-PSTAN in general showed the least. An explanation is suggested for this behaviour. The polymers PMMA and PMD were found to enhance flammability of the woods while PVDC, PAN, and PSTAN imparted fire resistance to the woods. Of the six local woods studied, Ramin-and-Keruing-polymer composites showed the highest flammable tendencies obtained. The correlation of thermal conductivity to flammability is discussed.

  13. AC Conductivity Studies in Lithium-Borate Glass Containing Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Shivaprakash, Y.; Anavekar, R. V.

    2011-07-01

    Gold nanoparticles have been synthesized in a base glass with composition 30Li2O-70B2O3 using gold chloride (HAuCl4.3H2O) as a dopant. The samples are characterized using XRD, ESR, SEM and optical absorption in the visible range. AC conductivity studies have been performed at RT over a frequency range 100 to 10 MHz. The dc conductivity is calculated from the complex impedence plot. The dc conductivity is found to be increasing with the increase of dopant concentration. AC conductivity data is fitted with Almond-West law with power exponent `s'. The values of `s' is found to lie in the range of 0.70-0.73.

  14. The conductive properties of single DNA molecules studied by torsion tunneling atomic force microscopy.

    PubMed

    Wang, W; Niu, D X; Jiang, C R; Yang, X J

    2014-01-17

    The conductive properties of single natural λ-DNA molecules are studied by torsion tunneling atomic force microscopy (TR-TUNA). The currents both parallel to and perpendicular to the DNA chains are investigated, but only weak or even no current signals are detected by TR-TUNA. To improve the conductance of DNA molecules, silver and copper metallized DNAs are fabricated and their conductivities are checked by TR-TUNA. It is found that for both Cu- and Ag-DNAs, the conductivity perpendicular to the DNA chain is enhanced significantly as the metal clusters are attached to the DNA chains. But parallel to the chain the electrical transport is still weak, most probably due to the 'beads-on-a-string' constructions of metallized DNAs.

  15. The conductive properties of single DNA molecules studied by torsion tunneling atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Wang, W.; Niu, D. X.; Jiang, C. R.; Yang, X. J.

    2014-01-01

    The conductive properties of single natural λ-DNA molecules are studied by torsion tunneling atomic force microscopy (TR-TUNA). The currents both parallel to and perpendicular to the DNA chains are investigated, but only weak or even no current signals are detected by TR-TUNA. To improve the conductance of DNA molecules, silver and copper metallized DNAs are fabricated and their conductivities are checked by TR-TUNA. It is found that for both Cu- and Ag-DNAs, the conductivity perpendicular to the DNA chain is enhanced significantly as the metal clusters are attached to the DNA chains. But parallel to the chain the electrical transport is still weak, most probably due to the ‘beads-on-a-string’ constructions of metallized DNAs.

  16. Studies on Proton Conducting Polymer Electrolytes Based on Pvdf-Pva with NH4NO3

    NASA Astrophysics Data System (ADS)

    Muthuvinayagam, M.; Gopinathan, C.; Rajeswari, N.; Selvasekarapandian, S.; Sanjeeviraja, C.

    2013-07-01

    PVDF-PVA polymer electrolytes with various blend ratios are prepared by solution casting technique with DMF (Merck) as solvent to optimize the blend ratio on the basis of high ionic conductivity. Then, different concentrations of NH4NO3 are doped with the optimized PVDF-PVA blend ratio and polymer blend electrolytes are prepared. The complex formation has been confirmed by XRD and FTIR analysis. The ac impedance studies are performed to evaluate the ionic conductivity of the polymer electrolyte membranes in the range 303-323K and it is found that the temperature dependence of ionic conductivity of the polymer blend electrolytes obey the Arrhenius relation. The maximum ionic conductivity is found to be 5.99×10-4 S/cm with activation energy Ea=0.21 eV for PVDF-PVA-NH4NO3 (80:20:0.4MWt%) polymer electrolyte.

  17. Authoritarian parenting attitudes as a risk for conduct problems Results from a British national cohort study.

    PubMed

    Thompson, Anne; Hollis, Chris; Dagger, David Richards

    2003-04-01

    This study examines the associations, and possible causal relationship, between mothers' authoritarian attitudes to discipline and child behaviour using cross-sectional and prospective data from a large population sample surveyed in the 1970 British Cohort Study. Results show a clear linear relationship between the degree of maternal approval of authoritarian child-rearing attitudes and the rates of conduct problems at age 5 and age 10. This association is independent of the confounding effects of socio-economic status and maternal psychological distress. Maternal authoritarian attitudes independently predicted the development of conduct problems 5 years later at age 10. The results of this longitudinal study suggest that authoritarian parenting attitudes expressed by mothers may be of significance in the development of conduct problems.

  18. In Situ Study of Strain-Dependent Ion Conductivity of Stretchable Polyethylene Oxide Electrolyte

    PubMed Central

    Kelly, Taylor; Ghadi, Bahar Moradi; Berg, Sean; Ardebili, Haleh

    2016-01-01

    There is a strong need in developing stretchable batteries that can accommodate stretchable or irregularly shaped applications including medical implants, wearable devices and stretchable electronics. Stretchable solid polymer electrolytes are ideal candidates for creating fully stretchable lithium ion batteries mainly due to their mechanical and electrochemical stability, thin-film manufacturability and enhanced safety. However, the characteristics of ion conductivity of polymer electrolytes during tensile deformation are not well understood. Here, we investigate the effects of tensile strain on the ion conductivity of thin-film polyethylene oxide (PEO) through an in situ study. The results of this investigation demonstrate that both in-plane and through-plane ion conductivities of PEO undergo steady and linear growths with respect to the tensile strain. The coefficients of strain-dependent ion conductivity enhancement (CSDICE) for in-plane and through-plane conduction were found to be 28.5 and 27.2, respectively. Tensile stress-strain curves and polarization light microscopy (PLM) of the polymer electrolyte film reveal critical insights on the microstructural transformation of stretched PEO and the potential consequences on ionic conductivity. PMID:26831948

  19. In Situ Study of Strain-Dependent Ion Conductivity of Stretchable Polyethylene Oxide Electrolyte

    NASA Astrophysics Data System (ADS)

    Kelly, Taylor; Ghadi, Bahar Moradi; Berg, Sean; Ardebili, Haleh

    2016-02-01

    There is a strong need in developing stretchable batteries that can accommodate stretchable or irregularly shaped applications including medical implants, wearable devices and stretchable electronics. Stretchable solid polymer electrolytes are ideal candidates for creating fully stretchable lithium ion batteries mainly due to their mechanical and electrochemical stability, thin-film manufacturability and enhanced safety. However, the characteristics of ion conductivity of polymer electrolytes during tensile deformation are not well understood. Here, we investigate the effects of tensile strain on the ion conductivity of thin-film polyethylene oxide (PEO) through an in situ study. The results of this investigation demonstrate that both in-plane and through-plane ion conductivities of PEO undergo steady and linear growths with respect to the tensile strain. The coefficients of strain-dependent ion conductivity enhancement (CSDICE) for in-plane and through-plane conduction were found to be 28.5 and 27.2, respectively. Tensile stress-strain curves and polarization light microscopy (PLM) of the polymer electrolyte film reveal critical insights on the microstructural transformation of stretched PEO and the potential consequences on ionic conductivity.

  20. Resistivity and Conductivity Studies of the Rattlesnake Springs, New Mexico Watershed

    NASA Astrophysics Data System (ADS)

    Santiago, C.; Doser, D. I.

    2009-12-01

    Rattlesnake Springs are a high-discharge artesian springs situated in the upper Black River Valley in southwestern Eddy Country, New Mexico. The aquifer that supplies the Rattlesnake Springs has been the main water source for domestic use by visitors of Carlsbad Caverns National Park and residents of neighboring ranches since the 1930s. Several geological studies relying on surface geology and limited water wells had previously been conducted in the area to examine the trend of ground water flow. We collected ground conductivity data at ~10m spacing around the perimeter and easily accessible areas owned by the National Park and surrounding ranches. In addition, we conducted Schlumberger and Wenner vertical electrical sounding at 10 sites, primarily to investigate the depth extend of conductivity anomalies, and a lateral resistivity survey across a suspected barrier to fluid flow. The conductivity and resistivity data indicate higher conductivities north and east of the springs reflecting moist soils, while two other highs at the eastern and western boundaries of the park are likely due to increased clay content of the soil.

  1. A feasibility study for conducting unattended night-time operations at WMKO

    NASA Astrophysics Data System (ADS)

    Stomski, Paul J.; Gajadhar, Sarah; Dahm, Scott; Jordan, Carolyn; Nordin, Tom

    2016-08-01

    In 2015, W. M. Keck Observatory conducted a study of the feasibility of conducting nighttime operations on Maunakea without any staff on the mountain. The study was motivated by the possibility of long term operational costs savings as well as other expected benefits. The goals of the study were to understand the technical feasibility and risk as well as to provide labor and cost estimates for implementation. The results of the study would be used to inform a decision about whether or not to fund and initiate a formal project aimed at the development of this new unattended nighttime operating capability. In this paper we will describe the study process as well as a brief summary of the results including the identified viable design alternative, the risk analysis, and the scope of work. We will also share the decisions made as a result of the study and current status of related follow-on activity.

  2. The Prediction of Speech Recognition in Noise With a Semi-Implantable Bone Conduction Hearing System by External Bone Conduction Stimulation With Headband: A Prospective Study.

    PubMed

    Ihler, Friedrich; Blum, Jenny; Berger, Max-Ulrich; Weiss, Bernhard G; Welz, Christian; Canis, Martin

    2016-10-03

    Semi-implantable transcutaneous bone conduction devices are treatment options for conductive and mixed hearing loss (CHL/MHL). For counseling of patients, realistic simulation of the functional result is desirable. This study compared speech recognition in noise with a semi-implantable transcutaneous bone conduction device to external stimulation with a bone conduction device fixed by a headband. Eight German-language adult patients were enrolled after a semi-implantable transcutaneous bone conduction device (Bonebridge, Med-El) was implanted and fitted. Patients received a bone conduction device for external stimulation (Baha BP110, Cochlear) fixed by a headband for comparison. The main outcome measure was speech recognition in noise (Oldenburg Sentence Test). Pure-tone audiometry was performed and subjective benefit was assessed using the Glasgow Benefit Inventory and Abbreviated Profile of Hearing Aid Benefit questionnaires. Unaided, patients showed a mean signal-to-noise ratio threshold of 4.6 ± 4.2 dB S/N for speech recognition. The aided results were -3.3 ± 7.2 dB S/N by external bone conduction stimulation and -1.2 ± 4.0 dB S/N by the semi-implantable bone conduction device. The difference between the two devices was not statistically significant, while the difference was significant between unaided and aided situation for both devices. Both questionnaires for subjective benefit favored the semi-implantable device over external stimulation. We conclude that it is possible to simulate the result of speech recognition in noise with a semi-implantable transcutaneous bone conduction device by external stimulation. This should be part of preoperative counseling of patients with CHL/MHL before implantation of a bone conduction device.

  3. Cu Doping in Ligand Free CdS Nanocrystals: Conductivity and Electronic Structure Study.

    PubMed

    Grandhi, G Krishnamurthy; Swathi, K; Narayan, K S; Viswanatha, Ranjani

    2014-07-03

    Ligand-free Cu-doped CdS nanocrystals (NCs) have been synthesized to elucidate their surface electronic structure. The Cu-doped ligand-free NCs unlike their undoped counterparts are shown to be luminescent. We used this Cu-related emission as a probe to study the nature of the surface trap states that results in negligible luminescence in the undoped NCs. The concentration of the sulfide ligands is shown to play a crucial role in the surface passivation of the NCs. Electrical conductivity of these NCs was also studied, and they were shown to exhibit significant conductivity of ∼10(-4) S cm(-1). Further we have shown that the electrical conductivity is closely correlated to the surface charge and hence the trap states of the individual NCs have far-reaching consequences in the device optimization.

  4. A study of rock matrix diffusion properties by electrical conductivity measurements

    SciTech Connect

    Ohlsson, Y.; Neretnieks, I.

    1999-07-01

    Traditional rock matrix diffusion experiments on crystalline rock are very time consuming due to the low porosity and extensive analysis requirements. Electrical conductivity measurements are, on the other hand, very fast and larger samples can be used than are practical in ordinary diffusion experiments. The effective diffusivity of a non-charged molecule is readily evaluated from the measurements, and influences from surface conductivity on diffusion of cations can be studied. A large number of samples of varying thickness can be measured within a short period, and the changes in transport properties with position in a rock core can be examined. In this study the formation factor of a large number of Aespoe diorite samples is determined by electrical conductivity measurements. The formation factor is a geometric factor defined as the ratio between the effective diffusivity of a non-charged molecule, to that of the same molecule in free liquid. The variation of this factor with position among a borecore and with sample length, and its coupling to the porosity of the sample is studied. Also the surface conductivity is studied. This was determined as the residual conductivity after leaching of the pore solution ions. The formation factor of most of the samples is in the range 1E-5 to 1E-4, with a mean value of about 5E-5. Even large samples (4--13 cm) give such values. The formation factor increases with increasing porosity and the change in both formation factor and porosity with position in the borecore can be large, even for samples close to each other. The surface conductivity increases with increasing formation factor for the various samples but the influence on the pore diffusion seems to be higher for samples of lower formation factor. This suggests that the relation between the pore surface area and the pore volume is larger for samples of low formation factor.

  5. Thermal conduction tensor imaging and energy flow analysis of brain: a feasibility study using MRI.

    PubMed

    Khundrakpam, Budhachandra S; Shukla, Vinay K; Roy, Prasun K

    2010-10-01

    The imaging of the distribution of thermal conductivity tensor at various points in a tissue is an essential need when accurate knowledge of heat energy flow in tissue is required for diagnostic and therapeutic management in oncology, neurology, and interventional radiology. Conventionally, tissue thermal conductivity is assumed as scalar, which induces errors in obtaining proper heat flow distribution. Using statistical thermodynamics principles, we present a method for constructing thermal conductivity tensor image of a tissue or an organ, using an MRI scanner. We elucidate the necessary tensorial cross-property relationship between different transport processes and confirm the same by experimental data. Using the proposed method, we perform a preliminary study of the procedure of thermal conductivity tensor imaging of the human brain as a case study. The methodology is quantitatively elucidated by measurement of tissue anisotropy distribution, tensor eigenvalues, and path tracking, along with three illustrative examples showing that transport properties estimated by the proposed thermal conductivity approach closely corroborates, with over 90% accuracy, to the experimentally measured values of the transport parameters which have been independently experimentally measured directly. By combining diffusion and perfusion tensor imaging approaches using mobility-encoding and spin-labelling methodologies respectively, we delineate the possible applications of this novel imaging modality to clinical problems of energy flow mapping involving biological heat transfer equations, such as planning of hyperthermic treatment to brain tumors, and electrode localization for deep brain stimulation in Parkinson's disease.

  6. Electrochemical studies of thin films of conducting polymers and conducting polymer composites deposited on metal and semiconductor electrodes

    NASA Technical Reports Server (NTRS)

    Nagasubramanian, G.; Di Stefano, S.; Moacanin, J.

    1987-01-01

    Electrochemical studies indicate that poly(Isothianaphthene) or PITN, can be p-doped only. Electrochemical properties of PITN and Nafion-PITN in acetonitrile solutions containing tetra-phenyl Phosphonium chloride as supporting electrolyte are compared. In both cases, the electrochemical behavior of thin films are different from that of thick films. In addition, Nafion does not seem to alter the electrochemical properties of PITN. Cyclic voltammetric and chronocoulometric measurements were made to compute the diffusion coefficient of the counter ions. Electrochemical behavior of both PITN and Nafion-PITN in acetonitrile solution containing different counter ions are described. PITN, when electrochemically deposited, apparently neither passivates surface states present nor forms ohmic contacts with p-Si or p(+)Si single-crystal electrodes.

  7. Childhood Bereavement: Psychopathology in the 2 Years Postparental Death

    ERIC Educational Resources Information Center

    Cerel, Julie; Fristad, Mary A.; Verducci, Joseph; Weller, Ronald A.; Weller, Elizabeth B.

    2006-01-01

    Objective: Although the death of a parent is one of the most significant stressors a child can experience, the psychiatric sequelae of parental death are not fully understood. Method: A total of 360 parent-bereaved children (ages 6-17) and their surviving parents were directly interviewed four times during the first 2 years following the death (at…

  8. [Constrictive pericarditis in children under 2 years of age].

    PubMed

    Silva, Lia; Anjos, Rui; Martins, Fernando Maymone; Telo, Margarida

    2002-01-01

    Two cases of constrictive pericarditis, in children under 2 years of age, of non-tuberculosis aetiology, diagnosed from June 97 to May 98 are reported. This entity is rare in paediatrics and it may progress to severe condition. Surgical treatment has a low risk and is generally associated with good prognosis. Aetiology, clinic presentation, differential diagnosis with restrictive cardiomyopathy and treatment are discussed.

  9. Intensity Accents in French 2 Year Olds' Speech.

    ERIC Educational Resources Information Center

    Allen, George D.

    The acoustic features and functions of accentuation in French are discussed, and features of accentuation in the speech of French 2-year-olds are explored. The four major acoustic features used to signal accentual distinctions are fundamental frequency of voicing, duration of segments and syllables, intensity of segments and syllables, and…

  10. USING CONTINUOUS MONITORS FOR CONDUCTING TRACER STUDIES IN WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    The use of online monitors for conducting a distribution system tracer study is proving to be an essential tool to accurately understand the flow dynamics in a distribution system. In a series of field testing sponsored by U. S. Environmental Protection Agency (EPA) and Greater ...

  11. Paychecks: A Guide to Conducting Salary-Equity Studies for Higher Education Faculty. Second Edition.

    ERIC Educational Resources Information Center

    Haignere, Lois

    This guidebook is designed as a resource for those in the higher education community who want to conduct analyses of bias in faculty salaries or to understand and interpret the results of studies presented to them. This edition will help readers detect gender and face bias in current rank, select a salary-equity consultant, understand different…

  12. 21 CFR 320.25 - Guidelines for the conduct of an in vivo bioavailability study.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Food and Drug Administration may permit this determination if the pharmacokinetics and the interactions... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Guidelines for the conduct of an in vivo bioavailability study. 320.25 Section 320.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH...

  13. 21 CFR 320.25 - Guidelines for the conduct of an in vivo bioavailability study.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Food and Drug Administration may permit this determination if the pharmacokinetics and the interactions... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Guidelines for the conduct of an in vivo bioavailability study. 320.25 Section 320.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH...

  14. 21 CFR 320.25 - Guidelines for the conduct of an in vivo bioavailability study.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Food and Drug Administration may permit this determination if the pharmacokinetics and the interactions... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Guidelines for the conduct of an in vivo bioavailability study. 320.25 Section 320.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH...

  15. Handbook of Instructions for Conducting Follow-Up Studies of High School Graduates. Book I.

    ERIC Educational Resources Information Center

    Donaldson, Evelyn T. Comp.; And Others

    This handbook is designed to enable high schools to conduct follow-up studies on their graduates for 5 years after graduation. The information gathered should give schools pertinent data about: (1) post high school activities of graduates; (2) reactions of graduates to counseling and guidance opportunities; (3) reactions of graduates to…

  16. The Use of Relational Databases as a Tool for Conducting Clinical Studies

    PubMed Central

    Miller, Randolph A.; Kapoor, Wishwa N.; Peterson, Jacqueline

    1983-01-01

    Many clinical investigators already have access to powerful university mainframe-based relational database management systems. Many of these programs, with minimal expense in time and money, can be employed to assist the investigator in conducting clinical trials. We describe our experience using one such general relational database system (System 1022) in completing several academic studies.

  17. Qualitative Research and Educational Leadership: Essential Dynamics to Consider When Designing and Conducting Studies

    ERIC Educational Resources Information Center

    Brooks, Jeffrey S.; Normore, Anthony H.

    2015-01-01

    Purpose: The purpose of this paper is to highlight issues relayed to appropriate design and conduct of qualitative studies in educational leadership. Design/Methodology/Approach: The paper is a conceptual/logical argument that centers around the notion that while scholars in the field have at times paid attention to such dynamics, it is important…

  18. 41 CFR 105-50.202-2 - Preparation of or assistance in the conduct of statistical or other studies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... assistance in the conduct of statistical or other studies. 105-50.202-2 Section 105-50.202-2 Public Contracts... statistical or other studies. (a) This service includes preparation of statistical or other studies and... available. (b) Specific areas in which GSA can conduct or participate in the conduct of studies include:...

  19. 41 CFR 105-50.202-2 - Preparation of or assistance in the conduct of statistical or other studies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... assistance in the conduct of statistical or other studies. 105-50.202-2 Section 105-50.202-2 Public Contracts... statistical or other studies. (a) This service includes preparation of statistical or other studies and... available. (b) Specific areas in which GSA can conduct or participate in the conduct of studies include:...

  20. 41 CFR 105-50.202-2 - Preparation of or assistance in the conduct of statistical or other studies.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... assistance in the conduct of statistical or other studies. 105-50.202-2 Section 105-50.202-2 Public Contracts... statistical or other studies. (a) This service includes preparation of statistical or other studies and... available. (b) Specific areas in which GSA can conduct or participate in the conduct of studies include:...

  1. Electrical conductivity of activated carbon-metal oxide nanocomposites under compression: a comparison study.

    PubMed

    Barroso-Bogeat, A; Alexandre-Franco, M; Fernández-González, C; Macías-García, A; Gómez-Serrano, V

    2014-12-07

    From a granular commercial activated carbon (AC) and six metal oxide (Al2O3, Fe2O3, SnO2, TiO2, WO3 and ZnO) precursors, two series of AC-metal oxide nanocomposites were prepared by wet impregnation, oven-drying at 120 °C, and subsequent heat treatment at 200 or 850 °C in an inert atmosphere. Here, the electrical conductivity of the resulting products was studied under moderate compression. The influence of the applied pressure, sample volume, mechanical work, and density of the hybrid materials was thoroughly investigated. The DC electrical conductivity of the compressed samples was measured at room temperature by the four-probe method. Compaction assays suggest that the mechanical properties of the nanocomposites are largely determined by the carbon matrix. Both the decrease in volume and the increase in density were relatively small and only significant at pressures lower than 100 kPa for AC and most nanocomposites. In contrast, the bulk electrical conductivity of the hybrid materials was strongly influenced by the intrinsic conductivity, mean crystallite size, content and chemical nature of the supported phases, which ultimately depend on the metal oxide precursor and heat treatment temperature. The supported nanoparticles may be considered to act as electrical switches either hindering or favouring the effective electron transport between the AC cores of neighbouring composite particles in contact under compression. Conductivity values as a rule were lower for the nanocomposites than for the raw AC, all of them falling in the range of semiconductor materials. With the increase in heat treatment temperature, the trend is toward the improvement of conductivity due to the increase in the crystallite size and, in some cases, to the formation of metals in the elemental state and even metal carbides. The patterns of variation of the electrical conductivity with pressure and mechanical work were slightly similar, thus suggesting the predominance of the pressure

  2. Recommended guidelines for the conduct and evaluation of prognostic studies in veterinary oncology.

    PubMed

    Webster, J D; Dennis, M M; Dervisis, N; Heller, J; Bacon, N J; Bergman, P J; Bienzle, D; Cassali, G; Castagnaro, M; Cullen, J; Esplin, D G; Peña, L; Goldschmidt, M H; Hahn, K A; Henry, C J; Hellmén, E; Kamstock, D; Kirpensteijn, J; Kitchell, B E; Amorim, R L; Lenz, S D; Lipscomb, T P; McEntee, M; McGill, L D; McKnight, C A; McManus, P M; Moore, A S; Moore, P F; Moroff, S D; Nakayama, H; Northrup, N C; Sarli, G; Scase, T; Sorenmo, K; Schulman, F Y; Shoieb, A M; Smedley, R C; Spangler, W L; Teske, E; Thamm, D H; Valli, V E; Vernau, W; von Euler, H; Withrow, S J; Weisbrode, S E; Yager, J; Kiupel, M

    2011-01-01

    There is an increasing need for more accurate prognostic and predictive markers in veterinary oncology because of an increasing number of treatment options, the increased financial costs associated with treatment, and the emotional stress experienced by owners in association with the disease and its treatment. Numerous studies have evaluated potential prognostic and predictive markers for veterinary neoplastic diseases, but there are no established guidelines or standards for the conduct and reporting of prognostic studies in veterinary medicine. This lack of standardization has made the evaluation and comparison of studies difficult. Most important, translating these results to clinical applications is problematic. To address this issue, the American College of Veterinary Pathologists' Oncology Committee organized an initiative to establish guidelines for the conduct and reporting of prognostic studies in veterinary oncology. The goal of this initiative is to increase the quality and standardization of veterinary prognostic studies to facilitate independent evaluation, validation, comparison, and implementation of study results. This article represents a consensus statement on the conduct and reporting of prognostic studies in veterinary oncology from veterinary pathologists and oncologists from around the world. These guidelines should be considered a recommendation based on the current state of knowledge in the field, and they will need to be continually reevaluated and revised as the field of veterinary oncology continues to progress. As mentioned, these guidelines were developed through an initiative of the American College of Veterinary Pathologists' Oncology Committee, and they have been reviewed and endorsed by the World Small Animal Veterinary Association.

  3. A study of phonon anisotropic scattering effect on silicon thermal conductivity at nanoscale

    SciTech Connect

    Bong, Victor N-S; Wong, Basil T.

    2015-08-28

    Previous studies have shown that anisotropy in phonon transport exist because of the difference in phonon dispersion relation due to different lattice direction, as observed by a difference in in-plane and cross-plane thermal conductivity. The directional preference (such as forward or backward scattering) in phonon propagation however, remains a relatively unexplored frontier. Our current work adopts a simple scattering probability in radiative transfer, which is called Henyey and Greenstein probability density function, and incorporates it into the phonon Monte Carlo simulation to investigate the effect of directional scattering in phonon transport. In this work, the effect of applying the anisotropy scattering is discussed, as well as its impact on the simulated thermal conductivity of silicon thin films. While the forward and backward scattering will increase and decrease thermal conductivity respectively, the extent of the effect is non-linear such that forward scattering has a more obvious effect than backward scattering.

  4. Thermal conductivity study at CH/Be interface by refraction-enhanced x-ray radiography

    NASA Astrophysics Data System (ADS)

    Ping, Yuan; Landen, Otto; Koch, Jeff; Hicks, Damien; Wallace, Russel; Collins, Gilbert

    2012-10-01

    Transport properties near the fuel-ablator interface at the edge of an ICF capsule are important for modeling the growth of hydrodynamic instabilities, which determines the mix level in the fuel and is critical for successful ignition (Hammel, et al. HEDP 6, 671, 2010). A novel technique, time-resolved refraction-enhanced x-ray radiography, is developed to study thermal conductivity at the interface (Ping et al. J. Instru. 2011). Experiments using OMEGA laser have been carried out for CH/Be targets isochorically heated by x-rays to measure the evolution of the density gradient at the interface due to thermal conduction. The sensitivity of this radiographic technique to discontinuities enabled observation of shock/rarefraction waves propagating away from the interface. Comparison of data and simulation results using various conductivity models will be presented.

  5. Lessons learned during the conduct of clinical studies in the dental PBRN.

    PubMed

    Gilbert, Gregg H; Richman, Joshua S; Gordan, Valeria V; Rindal, D Brad; Fellows, Jeffrey L; Benjamin, Paul L; Wallace-Dawson, Martha; Williams, O Dale

    2011-04-01

    Effectively addressing challenges of conducting research in nonacademic settings is crucial to its success. A dental practice-based research network called The Dental Practice-Based Research Network (DPBRN) is comprised of practitioner- investigators in two health maintenance organizations, several universities, many U.S. states, and three Scandinavian countries. Our objective in this article is to describe lessons learned from conducting studies in this research context; the studies are conducted by clinicians in community settings who may be doing their first research study. To date, twenty-one studies have been completed or are in implementation. These include a broad range of topic areas, enrollment sizes, and study designs. A total of 1,126 practitioner-investigators have participated in at least one study. After excluding one study because it involved electronic records queries only, these studies included more than 70,000 patient/participant units. Because the DPBRN is committed to being both practitioner- and patient-driven, all studies must be approved by its Executive Committee and a formal study section of academic clinical scientists. As a result of interacting with a diverse range of institutional and regulatory entities, funding agencies, practitioners, clinic staff, patients, academic scientists, and geographic areas, twenty-three key lessons have been learned. Patients' acceptance of these studies has been very high, judging from high participation rates and their completion of data forms. Early studies substantially informed later studies with regard to study design, practicality, forms design, informed consent process, and training and monitoring methods. Although time-intensive and complex, these solutions improved acceptability of practice-based research to patients, practitioners, and university researchers.

  6. Lessons Learned During the Conduct of Clinical Studies in The Dental PBRN

    PubMed Central

    Gilbert, Gregg H.; Richman, Joshua S.; Gordan, Valeria V.; Rindal, D. Brad; Fellows, Jeffrey L.; Benjamin, Paul L.; Wallace-Dawson, Martha; Williams, O. Dale

    2012-01-01

    Effectively addressing challenges of conducting research in nonacademic settings is crucial to its success. A dental practice-based research network called The Dental Practice-Based Research Network (DPBRN) is comprised of practitioner-investigators in two health maintenance organizations, several universities, many U.S. states, and three Scandinavian countries. Our objective in this article is to describe lessons learned from conducting studies in this research context; the studies are conducted by clinicians in community settings who may be doing their first research study. To date, twenty-one studies have been completed or are in implementation. These include a broad range of topic areas, enrollment sizes, and study designs. A total of 1,126 practitioner-investigators have participated in at least one study. After excluding one study because it involved electronic records queries only, these studies included more than 70,000 patient/participant units. Because the DPBRN is committed to being both practitioner- and patient-driven, all studies must be approved by its Executive Committee and a formal study section of academic clinical scientists. As a result of interacting with a diverse range of institutional and regulatory entities, funding agencies, practitioners, clinic staff, patients, academic scientists, and geographic areas, twenty-three key lessons have been learned. Patients’ acceptance of these studies has been very high, judging from high participation rates and their completion of data forms. Early studies substantially informed later studies with regard to study design, practicality, forms design, informed consent process, and training and monitoring methods. Although time-intensive and complex, these solutions improved acceptability of practice-based research to patients, practitioners, and university researchers. PMID:21460266

  7. A Checklist for the Conduct, Reporting, and Appraisal of Microcosting Studies in Health Care: Protocol Development

    PubMed Central

    Reiff, Marian

    2016-01-01

    Background Microcosting is a cost estimation method that requires the collection of detailed data on resources utilized, and the unit costs of those resources in order to identify actual resource use and economic costs. Microcosting findings reflect the true costs to health care systems and to society, and are able to provide transparent and consistent estimates. Many economic evaluations in health and medicine use charges, prices, or payments as a proxy for cost. However, using charges, prices, or payments rather than the true costs of resources can result in inaccurate estimates. There is currently no existing checklist or guideline for the conduct, reporting, or appraisal of microcosting studies in health care interventions. Objective The aim of this study is to create a checklist and guideline for the conduct, reporting, and appraisal of microcosting studies in health care interventions. Methods Appropriate potential domains and items will be identified through (1) a systematic review of all published microcosting studies of health and medical interventions, strategies, and programs; (2) review of published checklists and guidelines for economic evaluations of health interventions, and selection of items relevant for microcosting studies; and (3) theoretical analysis of economic concepts relevant for microcosting. Item selection, formulation, and reduction will be conducted by the research team in order to develop an initial pool of items for evaluation by an expert panel comprising individuals with expertise in microcosting and economic evaluation of health interventions. A modified Delphi process will be conducted to achieve consensus on the checklist. A pilot test will be conducted on a selection of the articles selected for the previous systematic review of published microcosting studies. Results The project is currently in progress. Conclusions Standardization of the methods used to conduct, report or appraise microcosting studies will enhance the

  8. Study on phase stability and ionic conductivity in TiIV-substituted bismuth vanadate

    NASA Astrophysics Data System (ADS)

    Beg, Saba; Haneef, Sadaf

    2014-09-01

    The solid solutions Bi4TixV2-xO11-(x/2)-δ in the composition range 0.05 ≤ x ≤ 0.30 were obtained by solid state reaction according to the substitution equation: ? The sample characterization and the study of phase transition were performed by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), alternating current (AC) impedance and electrical conductivity measurements. The solid solutions with composition 0.05 ≤ x ≤ 0.17 are isostructural with the orthorhombic β-phase, and those with x ≥ 0.20 represent tetragonal γ‧-phase as confirmed by the XRD and DSC results. Arrhenius plots of conductivity show that with increase in Ti concentration, the conductivity of solid solutions increase and reaches a maximum value of 4.38 × 10-5 Scm-1 for x = 0.17 at 340 °C. It is seen that the highly conducting tetragonal γ‧-phase is effectively stabilized to room temperature for the composition x ≥ 0.20. AC impedance plots show that the conductivity is mainly due to the grain and the grain boundary contribution which is confirmed by the existence of two semicircles along with an inclined spike.

  9. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste.

    PubMed

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-01

    Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10(-10), 2.08 × 10(-9) and 6.8 × 10(-10)m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m(3)). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH=2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m(3)) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  10. Thermal conductivity model for powdered materials under vacuum based on experimental studies

    NASA Astrophysics Data System (ADS)

    Sakatani, N.; Ogawa, K.; Iijima, Y.; Arakawa, M.; Honda, R.; Tanaka, S.

    2017-01-01

    The thermal conductivity of powdered media is characteristically very low in vacuum, and is effectively dependent on many parameters of their constituent particles and packing structure. Understanding of the heat transfer mechanism within powder layers in vacuum and theoretical modeling of their thermal conductivity are of great importance for several scientific and engineering problems. In this paper, we report the results of systematic thermal conductivity measurements of powdered media of varied particle size, porosity, and temperature under vacuum using glass beads as a model material. Based on the obtained experimental data, we investigated the heat transfer mechanism in powdered media in detail, and constructed a new theoretical thermal conductivity model for the vacuum condition. This model enables an absolute thermal conductivity to be calculated for a powder with the input of a set of powder parameters including particle size, porosity, temperature, and compressional stress or gravity, and vice versa. Our model is expected to be a competent tool for several scientific and engineering fields of study related to powders, such as the thermal infrared observation of air-less planetary bodies, thermal evolution of planetesimals, and performance of thermal insulators and heat storage powders.

  11. Single-Molecule Conductance Studies of Organometallic Complexes Bearing 3-Thienyl Contacting Groups.

    PubMed

    Bock, Sören; Al-Owaedi, Oday A; Eaves, Samantha G; Milan, David C; Lemmer, Mario; Skelton, Brian W; Osorio, Henrry M; Nichols, Richard J; Higgins, Simon J; Cea, Pilar; Long, Nicholas J; Albrecht, Tim; Martín, Santiago; Lambert, Colin J; Low, Paul J

    2017-02-10

    The compounds and complexes 1,4-C6 H4 (C≡C-cyclo-3-C4 H3 S)2 (2), trans-[Pt(C≡C-cyclo-3-C4 H3 S)2 (PEt3 )2 ] (3), trans-[Ru(C≡C-cyclo-3-C4 H3 S)2 (dppe)2 ] (4; dppe=1,2-bis(diphenylphosphino)ethane) and trans-[Ru(C≡C-cyclo-3-C4 H3 S)2 {P(OEt)3 }4 ] (5) featuring the 3-thienyl moiety as a surface contacting group for gold electrodes have been prepared, crystallographically characterised in the case of 3-5 and studied in metal|molecule|metal junctions by using both scanning tunnelling microscope break-junction (STM-BJ) and STM-I(s) methods (measuring the tunnelling current (I) as a function of distance (s)). The compounds exhibit similar conductance profiles, with a low conductance feature being more readily identified by STM-I(s) methods, and a higher feature by the STM-BJ method. The lower conductance feature was further characterised by analysis using an unsupervised, automated multi-parameter vector classification (MPVC) of the conductance traces. The combination of similarly structured HOMOs and non-resonant tunnelling mechanism accounts for the remarkably similar conductance values across the chemically distinct members of the family 2-5.

  12. Thermal conductivity studies of CdZnTe with varying Te excess

    SciTech Connect

    Jackson, Maxx; Bennett, Brittany; Giltnane, Dustin; Babalola, Stephen; Ohmes, Martin F.; Stowe, A. C.

    2016-08-28

    Cadmium Zine Telluride (CZT) has been extensively studied as a room temperature semiconductor gamma radiation detector. CZT continues to show promise as a bulk and pixelated gamma spectrometer with less than one percent energy resolution; however the fabrication costs are high. Improved yields of high quality, large CZT spectroscopy grade crystals must be achieved. CZT is grown by the Traveling Heater Method (THM) with a Te overpressure to account for vaporization losses. This procedure creates Te rich zones. During growth, boules will often cleave limiting the number of harvestable crystals. As a result, crystal growth parameter optimization was evaluated by modeling the heat flow within the system. Interestingly, Cadmium Telluride (CdTe) is used as a thermal conductivity surrogate in the absence of a thorough study of the CZT thermal properties. The current study has measured the thermal conductivity of CZT pressed powders with varying Te concentrations from 50-100% over 25-800°C to understand the variation in this parameter from CdTe. Cd0.9Zn0.1Te1.0 is the base CZT (designated 50%). CZT exhibits a thermal conductivity of nearly 1 W/mK, an order of magnitude greater than CdTe. Lastly, the thermal conductivity decreased with increasing Te concentration.

  13. Electrical conductivity and dielectric studies of MnO2 doped V2O5

    NASA Astrophysics Data System (ADS)

    Tan, Foo Khoon; Hassan, Jumiah; Wahab, Zaidan Abd.; Azis, Raba'ah Syahidah

    The investigation on electrical conductivity and dielectric properties of mixed oxide of manganese (Mn) and vanadium (V) was carried out to study the mixed oxides response to different frequencies and different measuring temperatures. The frequency and temperature dependence of AC conductivity, dielectric constant and dielectric loss factor of mixed oxides were studied in the frequency range of 40 Hz-1 MHz and a temperature range of 30-250 °C. Since the mixed oxides are multi phase materials, hence the properties of the pure oxides are also presented in this study to discuss the multi phase behaviour of the mixed oxides. The XRD pattern shows the Mn-V oxide is multiphase and quantitative phase analysis was performed to determine the relative phases. The overall results indicate that with increasing temperature, the AC conductivity, dielectric constant, dielectric loss factor and loss tangent of the Mn-V mixed oxide increases. However, it shows an overlap in the dielectric constant at 225 °C and 250 °C due to the V2O5 phase in the mixed oxide. From the AC activation energy, the mixed oxides underwent conduction mechanism transition from band to hopping in the investigated frequency range. The MnV2O6 has relatively good resistivity, therefore the mixed oxide sintered at 550 °C with the highest composition of MnV2O6 gives the highest dielectric constant of 9845 at 1 kHz, and at 250 °C.

  14. Thermal conductivity studies of CdZnTe with varying Te excess

    DOE PAGES

    Jackson, Maxx; Bennett, Brittany; Giltnane, Dustin; ...

    2016-08-28

    Cadmium Zine Telluride (CZT) has been extensively studied as a room temperature semiconductor gamma radiation detector. CZT continues to show promise as a bulk and pixelated gamma spectrometer with less than one percent energy resolution; however the fabrication costs are high. Improved yields of high quality, large CZT spectroscopy grade crystals must be achieved. CZT is grown by the Traveling Heater Method (THM) with a Te overpressure to account for vaporization losses. This procedure creates Te rich zones. During growth, boules will often cleave limiting the number of harvestable crystals. As a result, crystal growth parameter optimization was evaluated bymore » modeling the heat flow within the system. Interestingly, Cadmium Telluride (CdTe) is used as a thermal conductivity surrogate in the absence of a thorough study of the CZT thermal properties. The current study has measured the thermal conductivity of CZT pressed powders with varying Te concentrations from 50-100% over 25-800°C to understand the variation in this parameter from CdTe. Cd0.9Zn0.1Te1.0 is the base CZT (designated 50%). CZT exhibits a thermal conductivity of nearly 1 W/mK, an order of magnitude greater than CdTe. Lastly, the thermal conductivity decreased with increasing Te concentration.« less

  15. Thermal conductivity studies of CdZnTe with varying Te excess

    NASA Astrophysics Data System (ADS)

    Jackson, Maxx; Bennett, Brittany; Giltnane, Dustin; Babalola, Stephen; Ohmes, Martin F.; Stowe, A. C.

    2016-09-01

    Cadmium Zine Telluride (CZT) has been extensively studied as a room temperature semiconductor gamma radiation detector. CZT continues to show promise as a bulk and pixelated gamma spectrometer with less than one percent energy resolution; however the fabrication costs are high. Improved yields of high quality, large CZT spectroscopy grade crystals must be achieved. CZT is grown by the Traveling Heater Method (THM) with a Te overpressure to account for vaporization losses. This procedure creates Te rich zones. During growth, boules will often cleave limiting the number of harvestable crystals. As a result, crystal growth parameter optimization was evaluated by modeling the heat flow within the system. Interestingly, Cadmium Telluride (CdTe) is used as a thermal conductivity surrogate in the absence of a thorough study of the CZT thermal properties. The current study has measured the thermal conductivity of CZT pressed powders with varying Te concentrations from 50-100% over 25-800°C to understand the variation in this parameter from CdTe. Cd0.9Zn0.1Te1.0 is the base CZT (designated 50%). CZT exhibits a thermal conductivity of nearly 1 W/mK, an order of magnitude greater than CdTe. Further, the thermal conductivity decreased with increasing Te concentration.

  16. Impaired small fiber conduction in patients with Fabry disease: a neurophysiological case–control study

    PubMed Central

    2013-01-01

    Background Fabry disease is an inborn lysosomal storage disorder which is associated with small fiber neuropathy. We set out to investigate small fiber conduction in Fabry patients using pain-related evoked potentials (PREP). Methods In this case–control study we prospectively studied 76 consecutive Fabry patients for electrical small fiber conduction in correlation with small fiber function and morphology. Data were compared with healthy controls using non-parametric statistical tests. All patients underwent neurological examination and were investigated with pain and depression questionnaires. Small fiber function (quantitative sensory testing, QST), morphology (skin punch biopsy), and electrical conduction (PREP) were assessed and correlated. Patients were stratified for gender and disease severity as reflected by renal function. Results All Fabry patients (31 men, 45 women) had small fiber neuropathy. Men with Fabry disease showed impaired cold (p < 0.01) and warm perception (p < 0.05), while women did not differ from controls. Intraepidermal nerve fiber density (IENFD) was reduced at the lower leg (p < 0.001) and the back (p < 0.05) mainly of men with impaired renal function. When investigating A-delta fiber conduction with PREP, men but not women with Fabry disease had lower amplitudes upon stimulation at face (p < 0.01), hands (p < 0.05), and feet (p < 0.01) compared to controls. PREP amplitudes further decreased with advance in disease severity. PREP amplitudes and warm (p < 0.05) and cold detection thresholds (p < 0.01) at the feet correlated positively in male patients. Conclusion Small fiber conduction is impaired in men with Fabry disease and worsens with advanced disease severity. PREP are well-suited to measure A-delta fiber conduction. PMID:23705943

  17. Analytical study on two-phase MHD flow of electrically conducting magnetic fluid

    SciTech Connect

    Okubo, Masaaki; Ishimoto, Jun; Nishiyama, Hideya; Kamiyama, Shinichi

    1994-01-01

    An energy conversion system using magnetic fluids proposed by Resler and Rosensweig was based on the principle that the magnetization of magnetic fluids changes with temperature. However, significant results have not been obtained up to the present. To overcome this limit and to increase the acceleration of fluid flow the authors have contributed a new energy conversion system using two-phase flow produced by heat addition. This idea came from the two-phase liquid-metal MHD power generation system proposed by Petrick and Branover. If temperature sensitive magnetic fluids are used, such a system can produce a larger force than conventional systems because the properties of apparent magnetization change not only by temperature rise but also by gas inclusion. In the present paper, an analytical study is extended to the case of electrically conducting magnetic fluid as a basic study for demonstrating the possibility of application of electrically conducting magnetic fluid to working fluid in a liquid-metal MHD power generation system. Electrically conducting magnetic fluid is usually prepared by dispersing fine iron particles into a liquid metal such as mercury. To prevent a solidification of particles and keep a homogeneous dispersion, a thin film of tin is attached to the particle`s surface. Thus the electrically conducting liquid behaves as fluid itself having magnetization. The equations governing a one-dimensional boiling two-phase duct flow of such an electrically conducting magnetic fluid in a traverse magnetic field are numerically solved. The analytical results of the two-phase flow characteristics of the magnetic fluid are compared with ones of an electrically conducting nonmagnetic fluid.

  18. Meteoric dust effect on the lower E-region currents and conductivities - a statistical study

    NASA Astrophysics Data System (ADS)

    Muralikrishna, Polinaya; Vineeth, C.

    Electric field changes in the low latitude E-Region are attributed to changing neutral winds and to remote causes like the mapping of storm time electric field changes or changes in the neutral winds caused by Sudden Stratospheric Warming (SSW). Variation of electrojet currents is a manifestation of changing electric fields and/or electrical conductivities. Changes in the conductivity parameters, especially in the lower E-region are mainly caused by the ambient dust particles of meteoric origin. Statistical study of the monthly averaged meteor counts and the monthly occurrence of afternoon partial or total reversals in the electrojet currents during the years 2006 and 2007, clearly shows that the two parameters have a correlation coefficient as high as 0.94. This high correlation is seen even during geomagnetically disturbed periods. However, the high correlation is not seen in the two parameters when their daily averages are considered, most probably due to the delayed action of the dust particles on the conductivity parameters. The present study clearly shows that the meteoric dust particles play a very important role in altering the local electrical conductivities in the lower E-region. The possible physical processes responsible for this seem to be the capture of local free electrons by the ambient dust particles creating local electron bite outs and the reversal of the ambient polarization electric fields.

  19. First principles study of thermal conductivity cross-over in nanostructured zinc-chalcogenides

    SciTech Connect

    Katre, Ankita; Madsen, Georg K. H.; Togo, Atsushi; Tanaka, Isao

    2015-01-28

    Systematic first principles studies of zinc-chalcogenides have been performed to understand their thermal transport behaviour. We have applied the Boltzmann transport equation in the relaxation time approximation to calculate the thermal conductivity of ZnS, ZnSe, and ZnTe. We find a thermal conductivity cross-over between ZnS and ZnSe at nanostructure sizes around 0.1–0.2 μm and explain this in terms of the different contributions of phonon modes in these materials. We study the effect of nanostructuring using both the diffusive boundary scattering and confined mean free path limit and discuss the variations in the results. Furthermore, we show the strong influence of isotope scattering on the thermal conductivity. The calculated thermal conductivity is found to be strongly dependent on the volume and we explain the observed differences between local density and generalized gradient approximation calculations. We compare further calculated thermal properties, such as the thermal expansion coefficient, to experiment to validate our approach.

  20. Neurological Assessment and Nerve Conduction Study Findings in 22 Patients with Alkaptonuria from Jordan

    PubMed Central

    Alrawashdeh, Omar; Alsbou, Mohammad; Alzoubi, Hamed; Al-shagahin, Hani

    2017-01-01

    Alkaptonuria is a rare metabolic disease characterised by accumulative deposition of homogentisic acid in the connective tissue of the body. This results in early degeneration of tendons, cartilages, heart valves, and other tissues. The main objective of the study is to examine the possibility of the nervous system involvement in patients with alkaptonuria The sample consists of two groups; 22 patients with AKU and 20 controls. A neurological assessment has been carried out including detailed medical history, neurological examination, and a nerve conduction study of the nerves of the dominant hand. The prevalence of any abnormality was compared between the two groups using chi square test. The mean values of the nerve conduction study were compared between the two groups using student t-test. There was a higher prevalence of low back pain, hearing problems and tinnitus, numbness and neuropathic pain in alkaptonuria patients. There was no significant difference between the two groups in other conditions such as seizures, headache, and syncope. The values of the nerve conduction study did not show significant difference between the two groups. Neurologically related symptoms in alkaptonuria mostly represent complications of the connective tissue degeneration rather than direct involvement of the nervous system. This has been supported further by the normal findings of the neurophysiology study in patients with alkaptonuria. PMID:28217270

  1. Thermal conductivity of ordered-disordered material: a case study of superionic Ag2Te.

    PubMed

    Ouyang, Tao; Zhang, Xiaoliang; Hu, Ming

    2015-01-16

    Thermoelectric devices, which can generate electricity from waste heat, offer an attractive pathway for addressing an important niche in the globally growing landscape of energy demand. In the past few decades, the search for high-efficiency thermoelectrics has been guided by the concept of 'phonon-glass electron-crystal' (PGEC), i.e. an ideal thermoelectric material should have high carrier mobility and low thermal conductivity. Although remarkable progress has already been made along this line, the efficiency of thermoelectrics is still too poor to compete with other electricity producing methods. Ordered-disordered material, an emerging trend of high performance thermoelectrics under the concept of PGEC, is a new hot topic in the current thermoelectric research community. Taking superionic phase silver telluride (α-Ag2Te) as an example, we performed a comprehensive study of the thermal transport properties and of its physical mechanism by means of equilibrium molecular dynamic simulations. The results show that the thermal conductivity of α-Ag2Te is intrinsically very low. By analyzing the different contributions to the overall thermal conductivity, we revealed for the first time from atomistic simulations that the vibration of the Te(2-) sublattice dominates the thermal transport of α-Ag2Te, while the collision between the randomly diffusing Ag(+) ions and the Te(2-) sublattice yields a significant negative contribution to the thermal transport. We also studied the effect of isotropic compressive stain and carrier concentration on the thermal conductivity of α-Ag2Te. It has been found that the thermal conductivity can be largely reduced by applying compressive strain or with stoichiometric quantity modulation. Our studies shed light on the governing mechanism of thermal transport in ordered-disordered materials and could offer useful guidance for engineering the thermal transport properties of superionic conductors in terms of enhancing their thermoelectric

  2. AC Conductivity and Diffuse Reflectance Studies of Ag-TiO2 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Abdul Gafoor, A. K.; Musthafa, M. M.; Pradyumnan, P. P.

    2012-09-01

    Silver (Ag)-TiO2 nanoparticles synthesized by a low-temperature hydrothermal method in the anatase phase have been investigated by x-ray diffraction. Transmission electron microscopy has been used for morphological studies. Surface areas were studied by the Brunauer-Emmett-Teller method. Alternating-current (AC) conductivity and dielectric properties were studied for various dopant levels of 0.25 wt.%, 0.5 wt.%, and 1.0 wt.% at 300 K in the frequency range from 42 Hz to 5 MHz. AC conductivity and dielectric properties of TiO2 nanoparticles were greatly affected by loading with Ag. At high frequencies, the materials showed high AC conductivity and low dielectric constant. Diffuse reflectance studies were carried out for various dopant levels at 300 K by ultraviolet-visible (UV-Vis) spectroscopy. Considerable absorption of visible light by 0.5 wt.% and 1.0 wt.% Ag-TiO2 nanoparticles was observed due to the decrease of the energy band gap on Ag loading.

  3. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste

    SciTech Connect

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Examined the hydraulic conductivity evolution as function of dry density of Tunisian clay soil. Black-Right-Pointing-Pointer Follow the hydraulic conductivity evolution at long-term of three clay materials using the waste solution (pH=2.7). Black-Right-Pointing-Pointer Determined how compaction affects the hydraulic conductivity of clay soils. Black-Right-Pointing-Pointer Analyzed the concentration of F and P and examined the retention of each soil. - Abstract: Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 Multiplication-Sign 10{sup -10}, 2.08 Multiplication-Sign 10{sup -9} and 6.8 Multiplication-Sign 10{sup -10} m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m{sup 3}). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH = 2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m{sup 3}) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  4. Pharmacologic study of muscarinic receptor subtypes and arteriolar dilations: a comparison of conducted and local responses.

    PubMed

    Rivers, R J

    1999-03-01

    Arteriolar relaxation caused by the application of muscarinic agonists is mediated by multiple factors. One factor causes dilation only at the point of drug microapplication (local response), and a second factor causes responses remote (500 microm away) from the site of application (conducted response). This study was performed to determine if different muscarinic subtypes mediate the two responses. Arterioles of anesthetized hamster cheek pouch were studied with videomicroscopy. Muscarinic antagonists methscopolamine, scopolamine, pirenzepine, 4-DAMP (4-diphenylacetoxy-N-methylpiperidine methiodide), and AFDX-116 [(11-2[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5, 11-dihydro-6H-pyrido [2,3-b][1,4]benzodiazepin-6-one)] were cumulatively applied, and the K(B) for each antagonist was determined for the local and conducted responses caused by methacholine microapplication (10(-4) M, 5 s). The pK(B) (local, conducted) were not significantly different for the two responses when using scopolamine (10.5, 10.4). When the antagonist AFDX-116 (5.6, 6.3), selective for muscarinic receptor (m2) subtype was applied, the K(B) was greater for the conducted response. The pK(B) was greater, however, for the local response when the m1 subtype-selective pirenzepine (7.7, 6.9) or m3 subtype-selective 4-DAMP (10.1, 9.8) was applied. Thus the antagonist pK(B) ratio for on the local and conducted responses depends on the subtype selectivity of the antagonist. These data strongly suggest that different receptors are involved in the two responses.

  5. Comparing the similarity of responses received from studies in Amazon's Mechanical Turk to studies conducted online and with direct recruitment.

    PubMed

    Bartneck, Christoph; Duenser, Andreas; Moltchanova, Elena; Zawieska, Karolina

    2015-01-01

    Computer and internet based questionnaires have become a standard tool in Human-Computer Interaction research and other related fields, such as psychology and sociology. Amazon's Mechanical Turk (AMT) service is a new method of recruiting participants and conducting certain types of experiments. This study compares whether participants recruited through AMT give different responses than participants recruited through an online forum or recruited directly on a university campus. Moreover, we compare whether a study conducted within AMT results in different responses compared to a study for which participants are recruited through AMT but which is conducted using an external online questionnaire service. The results of this study show that there is a statistical difference between results obtained from participants recruited through AMT compared to the results from the participant recruited on campus or through online forums. We do, however, argue that this difference is so small that it has no practical consequence. There was no significant difference between running the study within AMT compared to running it with an online questionnaire service. There was no significant difference between results obtained directly from within AMT compared to results obtained in the campus and online forum condition. This may suggest that AMT is a viable and economical option for recruiting participants and for conducting studies as setting up and running a study with AMT generally requires less effort and time compared to other frequently used methods. We discuss our findings as well as limitations of using AMT for empirical studies.

  6. Techniques for Conducting Effective Concept Design and Design-to-Cost Trade Studies

    NASA Technical Reports Server (NTRS)

    Di Pietro, David A.

    2015-01-01

    Concept design plays a central role in project success as its product effectively locks the majority of system life cycle cost. Such extraordinary leverage presents a business case for conducting concept design in a credible fashion, particularly for first-of-a-kind systems that advance the state of the art and that have high design uncertainty. A key challenge, however, is to know when credible design convergence has been achieved in such systems. Using a space system example, this paper characterizes the level of convergence needed for concept design in the context of technical and programmatic resource margins available in preliminary design and highlights the importance of design and cost evaluation learning curves in determining credible convergence. It also provides techniques for selecting trade study cases that promote objective concept evaluation, help reveal unknowns, and expedite convergence within the trade space and conveys general practices for conducting effective concept design-to-cost studies.

  7. A facile approach for shape selective synthesis of rhodium nanostructures and conductivity studies

    SciTech Connect

    Sathe, Bhaskar R.

    2012-12-15

    Shape selective synthesis of Rh nanostructures has been demonstrated with the help of a single step chemical vapor deposition, where different shapes like cubes at 500 Degree-Sign C, pyramids and hexagons at 500 Degree-Sign C, 700 Degree-Sign C and 900 Degree-Sign C respectively have been obtained as a function of temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and four probe conductivity measurements were used to study the morphology, crystallinity and phase purity of the structures. The conductivity values for as synthesised nanostructures have been obtained in the range of 2-7 kS/cm{sup 2}. On the basis of the experimental results, from TGA and XPS studies possible mechanistic pathway for the evolution of Rh nanostructures was discussed.

  8. Feasibility study to conduct windblown sediment experiments aboard a space station

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Iversen, J. D.

    1983-01-01

    A feasibility study was undertaken to determine if a suitable apparatus could be designed to analyze aeolian processes for operation in space and to assess the feasibility of conducting meaningful experiments to address key aspects of aeolian processes. To meet this objective a prototype apparatus was fabricated and some limited experiments were run to determine its suitability for this application. At least three general types of experiments were devised that could be carried out aboard a space station: threshold studies, swirl (dust devil) experiments, and analyses of windblown particle trajectories. How experiments in a zero-g environment could advance knowledge of aeolian processes was studied.

  9. An experimental study on thermal conductivity and viscosity of nanofluids containing carbon nanotubes

    PubMed Central

    2014-01-01

    Recently, there has been considerable interest in the use of nanofluids for enhancing thermal performance. It has been shown that carbon nanotubes (CNTs) are capable of enhancing the thermal performance of conventional working liquids. Although much work has been devoted on the impact of CNT concentrations on the thermo-physical properties of nanofluids, the effects of preparation methods on the stability, thermal conductivity and viscosity of CNT suspensions are not well understood. This study is focused on providing experimental data on the effects of ultrasonication, temperature and surfactant on the thermo-physical properties of multi-walled carbon nanotube (MWCNT) nanofluids. Three types of surfactants were used in the experiments, namely, gum arabic (GA), sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS). The thermal conductivity and viscosity of the nanofluid suspensions were measured at various temperatures. The results showed that the use of GA in the nanofluid leads to superior thermal conductivity compared to the use of SDBS and SDS. With distilled water as the base liquid, the samples were prepared with 0.5 wt.% MWCNTs and 0.25% GA and sonicated at various times. The results showed that the sonication time influences the thermal conductivity, viscosity and dispersion of nanofluids. The thermal conductivity of nanofluids was typically enhanced with an increase in temperature and sonication time. In the present study, the maximum thermal conductivity enhancement was found to be 22.31% (the ratio of 1.22) at temperature of 45°C and sonication time of 40 min. The viscosity of nanofluids exhibited non-Newtonian shear-thinning behaviour. It was found that the viscosity of MWCNT nanofluids increases to a maximum value at a sonication time of 7 min and subsequently decreases with a further increase in sonication time. The presented data clearly indicated that the viscosity and thermal conductivity of nanofluids are influenced by the

  10. An experimental study on thermal conductivity and viscosity of nanofluids containing carbon nanotubes.

    PubMed

    Sadri, Rad; Ahmadi, Goodarz; Togun, Hussein; Dahari, Mahidzal; Kazi, Salim Newaz; Sadeghinezhad, Emad; Zubir, Nashrul

    2014-01-01

    Recently, there has been considerable interest in the use of nanofluids for enhancing thermal performance. It has been shown that carbon nanotubes (CNTs) are capable of enhancing the thermal performance of conventional working liquids. Although much work has been devoted on the impact of CNT concentrations on the thermo-physical properties of nanofluids, the effects of preparation methods on the stability, thermal conductivity and viscosity of CNT suspensions are not well understood. This study is focused on providing experimental data on the effects of ultrasonication, temperature and surfactant on the thermo-physical properties of multi-walled carbon nanotube (MWCNT) nanofluids. Three types of surfactants were used in the experiments, namely, gum arabic (GA), sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS). The thermal conductivity and viscosity of the nanofluid suspensions were measured at various temperatures. The results showed that the use of GA in the nanofluid leads to superior thermal conductivity compared to the use of SDBS and SDS. With distilled water as the base liquid, the samples were prepared with 0.5 wt.% MWCNTs and 0.25% GA and sonicated at various times. The results showed that the sonication time influences the thermal conductivity, viscosity and dispersion of nanofluids. The thermal conductivity of nanofluids was typically enhanced with an increase in temperature and sonication time. In the present study, the maximum thermal conductivity enhancement was found to be 22.31% (the ratio of 1.22) at temperature of 45°C and sonication time of 40 min. The viscosity of nanofluids exhibited non-Newtonian shear-thinning behaviour. It was found that the viscosity of MWCNT nanofluids increases to a maximum value at a sonication time of 7 min and subsequently decreases with a further increase in sonication time. The presented data clearly indicated that the viscosity and thermal conductivity of nanofluids are influenced by the

  11. An experimental study on thermal conductivity and viscosity of nanofluids containing carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Sadri, Rad; Ahmadi, Goodarz; Togun, Hussein; Dahari, Mahidzal; Kazi, Salim Newaz; Sadeghinezhad, Emad; Zubir, Nashrul

    2014-03-01

    Recently, there has been considerable interest in the use of nanofluids for enhancing thermal performance. It has been shown that carbon nanotubes (CNTs) are capable of enhancing the thermal performance of conventional working liquids. Although much work has been devoted on the impact of CNT concentrations on the thermo-physical properties of nanofluids, the effects of preparation methods on the stability, thermal conductivity and viscosity of CNT suspensions are not well understood. This study is focused on providing experimental data on the effects of ultrasonication, temperature and surfactant on the thermo-physical properties of multi-walled carbon nanotube (MWCNT) nanofluids. Three types of surfactants were used in the experiments, namely, gum arabic (GA), sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS). The thermal conductivity and viscosity of the nanofluid suspensions were measured at various temperatures. The results showed that the use of GA in the nanofluid leads to superior thermal conductivity compared to the use of SDBS and SDS. With distilled water as the base liquid, the samples were prepared with 0.5 wt.% MWCNTs and 0.25% GA and sonicated at various times. The results showed that the sonication time influences the thermal conductivity, viscosity and dispersion of nanofluids. The thermal conductivity of nanofluids was typically enhanced with an increase in temperature and sonication time. In the present study, the maximum thermal conductivity enhancement was found to be 22.31% (the ratio of 1.22) at temperature of 45°C and sonication time of 40 min. The viscosity of nanofluids exhibited non-Newtonian shear-thinning behaviour. It was found that the viscosity of MWCNT nanofluids increases to a maximum value at a sonication time of 7 min and subsequently decreases with a further increase in sonication time. The presented data clearly indicated that the viscosity and thermal conductivity of nanofluids are influenced by the

  12. Conductivity study of nitrogen-doped calcium zinc oxide prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Ting; Lan, Wen-How; Huang, Kai-Feng; Lin, Jia-Ching; Chang, Kuo-Jen

    2016-01-01

    In this study, the spray pyrolysis method was used to prepare unintentionally doped and nitrogen-doped calcium zinc oxide films by using zinc acetate, calcium nitrate precursor, and ammonium acetate precursor. Morphological and structural analyses were conducted using scanning electron microscopy and X-ray diffraction. The results indicated that film grain size decreased as the nitrogen doping was increased. Both calcium oxide and zinc oxide structures were identified in the unintentionally doped calcium zinc oxide. When nitrogen doping was introduced, the film mainly exhibited a zinc oxide structure with preferred (002) and (101) orientations. The concentration and mobility were investigated using a Hall measurement system. P-type films with a mobility and concentration of 10.6 cm2 V-1 s-1 and 2.8×1017 cm-3, respectively, were obtained. Moreover, according to a temperature-dependent conductivity analysis, an acceptor state with activation energy 0.266 eV dominated the p-type conduction for the unintentionally doped calcium zinc oxide. By contrast, a grain boundary with a barrier height of 0.274-0.292 eV dominated the hole conduction for the nitrogen-doped calcium zinc oxide films.

  13. Fluid stimulation elicits hearing in the absence of air and bone conduction--An animal study.

    PubMed

    Perez, Ronen; Adelman, Cahtia; Sohmer, Haim

    2016-01-01

    Conclusion Cochlea can be directly excited by fluid (soft-tissue) stimulation. Objective To determine whether there is no difference in auditory-nerve-brainstem evoked response (ABR) thresholds to fluid stimulation between normal and animal models of post radical-mastoidectomy, as seen in a previous human study. Background It has been shown in humans that hearing can be elicited with stimulation to fluid in the external auditory meatus (EAM), and radical-mastoidectomy cavity. These groups differed in age, initial hearing, and drilling exposure. To overcome this difference, experiments were conducted in sand-rats, first intact, and after inducing a radical-mastoidectomy. Methods The EAM of five sand-rats was filled with 0.3 ml saline. ABR thresholds were determined in response to vibratory stimulation by a clinical bone-vibrator with a plastic rod, applied to the saline in the EAM. Then the tympanic membrane was removed, and malleus dislocated (radical-mastoidectomy model). The cavity was filled with 0.45 ml saline and the ABR threshold was determined in response to vibratory stimulation to the cavity fluid. Results There was no difference in ABR fluid thresholds to EAM and mastoidectomy cavity stimulation. Air-conduction stimulation from the bone-vibrator was not involved (conductive loss due to fluid). Bone-conduction stimulation was not involved (large difference in acoustic impedance between fluid and bone).

  14. Child Weight Growth Trajectory and its Determinants in a Sample of Iranian Children from Birth until 2 Years of Age

    PubMed Central

    Hosseini, Sayed-Mohsen; Maracy, Mohamad-Reza; Sarrafzade, Sheida; Kelishadi, Roya

    2014-01-01

    Background: Growth is one of the most important indices in child health. The best and most effective way to investigate child health is measuring the physical growth indices such as weight, height and head circumference. Among these measures, weight growth is the simplest and the most effective way to determine child growth status. Weight trend at a given age is the result of cumulative growth experience, whereas growth velocity represents what is happening at the time. Methods: This longitudinal study was conducted among 606 children repeatedly measured from birth until 2 years of age. We used linear mixed model to analyze repeated measures and to determine factors affecting the growth trajectory. LOWESS smooth curve was used to draw velocity curves. Results: Gender, child rank, birth status and feeding mode had a significant effect on weight trajectory. Boys had higher weight during the study. Infants with exclusive breast feeding had higher weight than other infants. Boys had higher growth velocity up to age 6 month. Breast fed infants had higher growth velocity up to 6 month, but thereafter the velocity was higher in other infants. Conclusions: Many of the studies have investigated child growth, but most of them used cross-sectional design. In this study, we used longitudinal method to determine effective factors on weight trend in children from birth until 2-year-old. The effects of perinatal factors on further growth should be considered for prevention of growth disorders and their late complications. PMID:24829720

  15. Fibroblast proliferation alters cardiac excitation conduction and contraction: a computational study*

    PubMed Central

    Zhan, He-qing; Xia, Ling; Shou, Guo-fa; Zang, Yun-liang; Liu, Feng; Crozier, Stuart

    2014-01-01

    In this study, the effects of cardiac fibroblast proliferation on cardiac electric excitation conduction and mechanical contraction were investigated using a proposed integrated myocardial-fibroblastic electromechanical model. At the cellular level, models of the human ventricular myocyte and fibroblast were modified to incorporate a model of cardiac mechanical contraction and cooperativity mechanisms. Cellular electromechanical coupling was realized with a calcium buffer. At the tissue level, electrical excitation conduction was coupled to an elastic mechanics model in which the finite difference method (FDM) was used to solve electrical excitation equations, and the finite element method (FEM) was used to solve mechanics equations. The electromechanical properties of the proposed integrated model were investigated in one or two dimensions under normal and ischemic pathological conditions. Fibroblast proliferation slowed wave propagation, induced a conduction block, decreased strains in the fibroblast proliferous tissue, and increased dispersions in depolarization, repolarization, and action potential duration (APD). It also distorted the wave-front, leading to the initiation and maintenance of re-entry, and resulted in a sustained contraction in the proliferous areas. This study demonstrated the important role that fibroblast proliferation plays in modulating cardiac electromechanical behaviour and which should be considered in planning future heart-modeling studies. PMID:24599687

  16. Preliminary Study on the Lesion Location and Prognosis of Cubital Tunnel Syndrome by Motor Nerve Conduction Studies

    PubMed Central

    Liu, Zhu; Jia, Zhi-Rong; Wang, Ting-Ting; Shi, Xin; Liang, Wei

    2015-01-01

    Background: To study lesions’ location and prognosis of cubital tunnel syndrome (CubTS) by routine motor nerve conduction studies (MNCSs) and short-segment nerve conduction studies (SSNCSs, inching test). Methods: Thirty healthy subjects were included and 60 ulnar nerves were studied by inching studies for normal values. Sixty-six patients who diagnosed CubTS clinically were performed bilaterally by routine MNCSs and SSNCSs. Follow-up for 1-year, the information of brief complaints, clinical symptoms, and physical examination were collected. Results: Sixty-six patients were included, 88 of nerves was abnormal by MNCS, while 105 was abnormal by the inching studies. Medial epicondyle to 2 cm above medial epicondyle is the most common segment to be detected abnormally (59.09%), P < 0.01. Twenty-two patients were followed-up, 17 patients’ symptoms were improved. Most of the patients were treated with drugs and modification of bad habits. Conclusions: (1) SSNCSs can detect lesions of compressive neuropathy in CubTS more precisely than the routine motor conduction studies. (2) SSNCSs can diagnose CubTS more sensitively than routine motor conduction studies. (3) In this study, we found that medial epicondyle to 2 cm above the medial epicondyle is the most vulnerable place that the ulnar nerve compressed. (4) The patients had a better prognosis who were abnormal in motor nerve conduction time only, but not amplitude in compressed lesions than those who were abnormal both in velocity and amplitude. Our study suggests that SSNCSs is a practical method in detecting ulnar nerve compressed neuropathy, and sensitive in diagnosing CubTS. The compound muscle action potentials by SSNCSs may predict prognosis of CubTS. PMID:25947398

  17. Communication Apprehension: Levels of First-Generation College Students at 2-Year Institutions

    ERIC Educational Resources Information Center

    Francis, Trevor A.; Miller, Michael T.

    2008-01-01

    The study explored the oral communication apprehension (CA) levels of first-generation college students at a 2-year case study community institution. Overall and general-context CA were measured using the Personal Report of Communication Apprehension-24 (PRCA-24). The survey was sent by e-mail to 2,040 institutionally-identified first-generation…

  18. Conductivity percolation in loosely compacted microcrystalline cellulose: An in situ study by dielectric spectroscopy during densification.

    PubMed

    Nilsson, Martin; Frenning, Göran; Gråsjö, Johan; Alderborn, Göran; Strømme, Maria

    2006-10-19

    The present study aims at contributing to a complete understanding of the water-induced ionic charge transport in cellulose. The behavior of this transport in loosely compacted microcrystalline cellulose (MCC) powder was investigated as a function of density utilizing a new type of measurement setup, allowing for dielectric spectroscopy measurement in situ during compaction. The ionic conductivity in MCC was found to increase with increasing density until a leveling-out was observed for densities above approximately 0.7 g/cm3. Further, it was shown that the ionic conductivity vs density followed a percolation type behavior signifying the percolation of conductive paths in a 3D conducting network. The density percolation threshold was found to be between approximately 0.2 and 0.4 g/cm3, depending strongly on the cellulose moisture content. The observed percolation behavior was attributed to the forming of interparticulate bonds in the MCC and the percolation threshold dependence on moisture was linked to the moisture dependence of particle rearrangement and plastic deformation in MCC during compaction. The obtained results add to the understanding of the density-dependent water-induced ionic transport in cellulose showing that, at given moisture content, the two major parameters determining the magnitude of the conductivity are the connectedness of the interparticluate bonds and the connectedness of pores with a diameter in the 5-20 nm size range. At densities between approximately 0.7 and 1.2 g/cm3 both the bond and the pore networks have percolated, facilitating charge transport through the MCC compact.

  19. Negative symptom improvement during cognitive rehabilitation: results from a 2-year trial of Cognitive Enhancement Therapy.

    PubMed

    Eack, Shaun M; Mesholam-Gately, Raquelle I; Greenwald, Deborah P; Hogarty, Susan S; Keshavan, Matcheri S

    2013-08-30

    Cognitive rehabilitation has shown beneficial effects on cognition in patients with schizophrenia, which may also help to improve negative symptoms due to overlapping pathophysiology between these two domains. To better understand the possible relationship between these areas, we conducted an exploratory analysis of the effects of Cognitive Enhancement Therapy (CET) on negative symptoms. Early course schizophrenia outpatients (n=58) were randomized to 2 years of CET or an Enriched Supportive Therapy (EST) control condition. Results revealed significant and medium-sized (d=0.61) differential improvements favoring CET in overall negative symptoms, particularly social withdrawal, affective flattening, and motor retardation. Neurocognitive improvement was associated with reduced negative symptoms in CET, but not EST patients. No relationships were observed between improvements in emotion processing aspects of social cognition, as measured by the Mayer-Salovey-Caruso Emotional Intelligence Test, and negative symptoms. CET represents an effective cognitive rehabilitation intervention for schizophrenia that may also have benefits to negative symptoms. Future studies specifically designed to examine negative symptoms during the course of cognitive rehabilitation are needed.

  20. A 2-year young adult obesity prevention trial in the US: Process evaluation results.

    PubMed

    Laska, Melissa N; Sevcik, Sarah M; Moe, Stacey G; Petrich, Christine A; Nanney, Marilyn S; Linde, Jennifer A; Lytle, Leslie A

    2016-12-01

    Our objective was to conduct a process evaluation of the CHOICES (Choosing Healthy Options in College Environments and Settings) study, a large, randomized, controlled trial designed to prevent unhealthy weight gain in young adults (aged 18-35) attending 2-year community colleges in the USA. The 24-month intervention consisted of participation in an academic course and a social networking and support website. Among intervention participants, completion rates for most course activities were >80%, reflecting a high level of dose received. Course retention and participant satisfaction were also high. Engagement results, however, were mixed with less than half of participants in the online and hybrid sections of the course reporting that they interacted with course materials ≥3 h/week, but 50-75% reporting that they completed required lessons 'all/very thoroughly'. Engagement in the website activities was also mixed with more than half of intervention participants logging onto the website during the first month, but then declining to 25-40% during the following 23 months of the intervention. Intervention engagement is a challenge of online interventions and a challenge of working with the young adult age group in general. Additional research is needed to explore strategies to support engagement among this population, particularly for relatively long intervention durations.

  1. Study of the solution thermal conductivity effect on nonlinear refraction of colloidal gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Sarkhosh, L.; Mansour, N.

    2015-06-01

    In nanoparticle colloidal systems, the thermal nonlinearity is affected by the thermal parameters of the surrounding solution. Having a low temperature gradient rate solution may be a key factor in producing high thermal nonlinear properties in colloids. In this manuscript, the effect of the thermal conductivity of the surrounding liquid environment on the thermal nonlinear refraction of gold nanoparticles (AuNPs) synthesized by laser ablation of a gold target in different solutions is investigated. Gold nanoparticles colloids have been fabricated by the nanosecond pulsed laser ablation of a pure gold plate in different liquid environments with a thermal conductivity range of 0.14-0.60 W mK-1 including cyclohexanone, castor oil, dimethyl sulfoxide, ethylene glycol, glycerin and water. The AuNPs colloids exhibit a UV-Vis absorption spectrum with a surface plasmon absorption peak at about 540  ±  20 nm. The thermal nonlinear optical responses of the gold colloids are measured using the Z-scan technique under low power CW laser irradiation at 532 nm near the surface plasmon peak of the nanoparticles. Our results show that the nonlinear refractive index of the nanoparticle colloids is considerably affected by the thermal conductivity of liquid medium. The largest nonlinear refractive index of -3.1  ×  10-7 cm2 W-1 is obtained for AuNP in cyclohexanone with the lowest thermal conductivity of 0.14 W mK-1 whereas the lowest one of -0.1  ×  10-7 cm2 W-1 is obtained for AuNP in water with the highest thermal conductivity of 0.60 W mK-1. This study shows that the nonlinear refractive index value of colloids can be controlled by the thermal conductivity of the used liquid’s environment. This allows us to design low threshold optical limiters by choosing a solution with low thermal conductivity for colloidal nanoparticles.

  2. Brainstem Auditory Evoked Potentials (BAEP)- A Pilot Study Conducted on Young Healthy Adults from Central India

    PubMed Central

    Gandhe, Mahendra Bhauraoji; Gandhe, Swapnali Mahendra; Puttewar, A.N.; Saraf, Chhaya; Singh, Ramji

    2014-01-01

    Objective: To Evaluate I, II, III, IV, V wave latencies and I-III, III-V, I-V inter-peak latencies and V/I wave amplitude ratio in Normal subjects in Central India. Methods: We recorded BAEP from 50 healthy normal subjects from the community of same sex and geographical setup. The absolute, interpeak and wave V/I amplitude ratio were measurement and recording was done using RMS EMG EP MARK II machine manufactured by RMS recorders and Medicare system, Chandigarh. Result: Absolute, interpeak and wave V/I amplitude ratio were measured in normal subjects and compared with other previous studies. Conclusion: This study was conducted as exploratory pilot study only on male healthy controls. Since, the study conducted in different regions, there are some differences in the latencies and interpeak latencies and amplitude ratio but they are within range, so reference range of this study can be used for future studies in this Wardha region of Central India. PMID:25120971

  3. A PIC Simulation Study of Electron Viscosity and Thermal Conduction in Collisionless Plasmas

    NASA Astrophysics Data System (ADS)

    Riquelme, Mario; Quataert, Eliot; Verscharen, Daniel

    2016-10-01

    We use particle-in-cell (PIC) simulations to study the interplay between electron- and ion-scale velocity-space instabilities and their effect on electron pressure anisotropy, viscous heating, and thermal conduction. The adiabatic invariance of the magnetic moment in low-collisionality plasmas gives rise to pressure anisotropy, with p⊥ , j -p∥ , j > 0 (< 0) if the magnetic field magnitude | B-> | grows (decreases), where p⊥ , j and p∥ , j denote the pressure of species j [electron or ion] perpendicular and parallel to B-> . If the resulting anisotropy is large enough, it can trigger small-scale plasma instabilities. By imposing a shear in the plasma we either amplify or decrease the magnetic field | B-> | . When | B-> | is amplified, we explored the nonlinear regime of the mirror, ion-cyclotron, and electron whistler instabilities. When | B-> | is decreased, we studied the nonlinear regime of the ion- and electron-firehose instabilities. We discuss the implications of our results for electron heating and thermal conduction in low-collisionality accretion flows onto black holes, like Sgr A*. We also discuss the possible implications for the thermal conductivity of plasma in the outer parts of massive, hot, galaxy clusters.

  4. Study of the electrical conductivity at finite temperature in 2D Si- MOSFETs

    SciTech Connect

    Limouny, L. Kaaouachi, A. El Tata, O.; Daoudi, E.; Errai, M.; Dlimi, S.; Idrissi, H. El; Zatni, A.

    2014-01-27

    We investigate the low temperature density dependent conductivity of two dimensional electron systems in zero magnetic field for sample Si-15 MOSFETs. The first purpose of this paper is to establish that the knee of the conductivity σ{sub 0} (σ{sub 0} is the T = 0.3 conductivity obtained by linear extrapolation of the curves of σ (T) for different values of electron density, n{sub s}) as a function of the carrier densities n{sub s} for T = 0.3 K, observed by Lai et al. and Limouny et al. in previous work for two different samples, is independent of temperature. The second aim is the determination of the critical density, n{sub c}, of the metal-insulator transition. Many methods are used in this investigation of n{sub c} which have been already used for other samples. The motivation behind this last study is the observation of many values of n{sub c} that have been obtained from different methods and that are slightly different. We will use in this study three methods with the intention to infer which one is more appropriate to obtain n{sub c}.

  5. Conductive Education as a Method of Stroke Rehabilitation: A Single Blinded Randomised Controlled Feasibility Study

    PubMed Central

    Jutley-Neilson, Jagjeet; Russell, Nicholas C. C.; Sackley, Catherine M.

    2016-01-01

    Background. Conductive Education for stroke survivors has shown promise but randomised evidence is unavailable. This study assessed the feasibility of a definitive randomised controlled trial to evaluate efficacy. Methods. Adult stroke survivors were recruited through local community notices. Those completing the baseline assessment were randomised using an online program and group allocation was independent. Intervention group participants received 10 weekly 1.5-hour sessions of Conductive Education at the National Institute of Conductive Education in Birmingham, UK. The control group participants attended two group meetings. The study evaluated the feasibility of recruitment procedures, delivery of the intervention, retention of participants, and appropriateness of outcome measures and data collection methods. Independent assessments included the Barthel Index, the Stroke Impact Scale, the Timed Up and Go test, and the Hospital Anxiety and Depression Scale. Results. Eighty-two patients were enrolled; 77 completed the baseline assessment (46 men, mean age 62.1 yrs.) and were randomised. 70 commenced the intervention (n = 37) or an equivalent waiting period (n = 33). 32/37 completed the 10-week training and 32/33 the waiting period. There were no missing items from completed questionnaires and no adverse events. Discussion. Recruitment, intervention, and assessment methods worked well. Transport issues for intervention and assessment appointments require review. Conclusion. A definitive trial is feasible. This trial is registered with ISRCTN84064492. PMID:27418997

  6. AC impedance spectroscopy and conductivity studies of Dy doped Bi4V2O11 ceramics

    NASA Astrophysics Data System (ADS)

    Bag, Sasmitarani; Das, Parthasarathi; Behera, Banarji

    2017-03-01

    The ac impedance and conductivity properties of Dy doped Bi4V2 - x Dy x O11 (x = 0.05, 0.10, 0.15 and 0.20) ceramics prepared by solid-state reaction technique, in a wide frequency range at different temperatures have been studied. All the samples exhibited β-type phase orthorhombic structure at room temperature. The Nyquist plot confirmed the presence of both grain and grain boundary effects for all Dy doped samples. Double relaxation behavior was also observed. The grain and grain boundary resistance decreases with rise in temperature for all the concentration and exhibits a typical negative temperature co-efficient of resistance (NTCR) behavior. An analysis of the electric modulus suggests the possible hopping mechanism for electrical transport processes of all the materials. The ac conductivity spectrum obeys Jonscher's universal power law. DC conductivity of the materials were also studied and values of the activation energy found to be 0.40, 0.49, 0.73 and 0.78 eV for the compositions x = 0.05, 0.10, 0.15 and 0.20, respectively, at different temperatures (150-375 °C).

  7. Analytical study of electrophoretic characterization of kidney cells. [conducted during the Apollo Soyuz Test Project

    NASA Technical Reports Server (NTRS)

    Knox, R. J.

    1978-01-01

    Embryonic kidney cells were studied as a follow-up to the MA-011 Electrophoresis Technology Experiment which was conducted during the Apollo Soyuz Test Project (ASTP). The postflight analysis of the performance of the ASTP zone electrophoresis experiment involving embryonic kidney cells is reported. The feasibility of producing standard particles for electrophoresis was also studied. This work was undertaken in response to a need for standardization of methods for producing, calibrating, and storing electrophoretic particle standards which could be employed in performance tests of various types of electrophoresis equipment. Promising procedures were tested for their suitability in the production of standard test particles from red blood cells.

  8. Analysis on Thermal Conductivity of Graphite/Al Composite by Experimental and Modeling Study

    NASA Astrophysics Data System (ADS)

    Xue, C.; Bai, H.; Tao, P. F.; Jiang, N.; Wang, S. L.

    2017-01-01

    Graphite/Al composites were fabricated by vacuum hot pressing technology in this study. The main factors affecting the thermal conductivity (TC) of graphite/Al composites were deeply investigated by experimental and modeling study. The results showed that the TC of graphite/Al composite can be improved via designing the preferred orientation of graphite flakes, selecting graphite flakes with large diameter, increasing the content of graphite flakes in graphite/Al composite and solving the poor wettability between Al and graphite. The modified model can well predict the heat transfer behavior of graphite/Al composite.

  9. AC conductivity and electrochemical studies of PVA/PEG based polymer blend electrolyte films

    NASA Astrophysics Data System (ADS)

    Polu, Anji Reddy; Kumar, Ranveer; Dehariya, Harsha

    2012-06-01

    Polymer blend electrolyte films based on Polyvinyl alcohol(PVA)/Poly(ethylene glycol)(PEG) and magnesium nitrate (Mg(NO3)2) were prepared by solution casting technique. Conductivity in the temperature range 303-373 K and transference number measurements have been employed to investigate the charge transport in this polymer blend electrolyte system. The highest conductivity is found to be 9.63 × 10-5 S/cm at 30°C for sample with 30 weight percent of Mg(NO3)2 in PVA/PEG blend matrix. Transport number data shows that the charge transport in this polymer electrolyte system is predominantly due to ions. Using this electrolyte, an electrochemical cell with configuration Mg/(PVA+PEG+Mg(NO3)2)/(I2+C+electrolyte) was fabricated and its discharge characteristics profile has been studied.

  10. Tuning the thermal conductivity of silicon carbide by twin boundary: a molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Liu, Qunfeng; Luo, Hao; Wang, Liang; Shen, Shengping

    2017-02-01

    Silicon carbide (SiC) is a semiconductor with excellent mechanical and physical properties. We study the thermal transport in SiC by using non-equilibrium molecular dynamics simulations. The work is focused on the effects of twin boundaries and temperature on the thermal conductivity of 3C-SiC. We find that compared to perfect SiC, twinned SiC has a markedly reduced thermal conductivity when the twin boundary spacing is less than 100 nm. The Si-Si twin boundary is more effective to phonon scattering than the C-C twin boundary. We also find that the phonon scattering effect of twin boundary decreases with increasing temperature. Our findings provide insights into the thermal management of SiC-based electronic devices and thermoelectric applications.

  11. Compensated Arrhenius formalism applied to a conductivity study in poly(propylene glycol) diacrylate monomers.

    PubMed

    Dubois, F; Derouiche, Y; Leblond, J M; Maschke, U; Douali, R

    2015-09-01

    The temperature dependence of the ionic conductivity is studied in a series of poly(propylene glycol) diacrylate monomers. The experimental data are analyzed by means of the approach recently proposed by Petrowsky et al. [J. Phys. Chem. B. 113, 5996 (2009)10.1021/jp810095g]. This so-called compensated Arrhenius formalism (CAF) approach takes into account the influence of the dielectric permittivity on the exponential prefactor in the classical Arrhenius equation. The experimental data presented in this paper show a good agreement with the CAF; this means that the exponential prefactor is principally dielectric permittivity dependent. The compensated data revealed two conduction processes with different activation energies; they correspond to low and high temperature ranges, respectively.

  12. Electron thermalization and attachment in pulse-irradiated oxygen studied by time-resolved microwave conductivity

    NASA Astrophysics Data System (ADS)

    Warman, John M.; Cooper, Ronald

    The microwave conductivity of oxygen gas following nanosecond pulsed irradiation has been studied for pressures from 5 to 50 torr. The conductivity is found to decrease by a factor of approx. 20 in the early stages ( tN < 2 x 10 11 s cm -3) following the pulse. This is attributed to a decrease in the electron collision frequency as the initial excess energy of the electrons becomes degraded. A further decrease found at longer times is due to the three-body attachment of electrons to O 2 with a rate constant of 2.4 x 10 -30 cm 6s -1. Above a pressure of approx. 30 torr significant attachment begins to occur while electrons are still superthermal. The time at which the microwave signal is within 10% of the value corresponding to thermal energies is given by τ thP ≈ 15 μs.torr.

  13. Doping and Thermal Conductivity Studies of CrSiTe3

    NASA Astrophysics Data System (ADS)

    Haglund, Amanda; Yan, Jiaqiang; Keppens, Veerle; Mandrus, David

    CrSiTe3 is a layered material with a 2-dimensional crystal structure, and has recently become of more interest due to the possibility of using its ferromagnetic and semiconducting properties for spintronics applications. To further investigate the properties of CrSiTe3, we doped it with various transition elements on the Cr site in an attempt to tune and control the magnetism, as well as study changes in the thermal conductivity. We synthesized pure CrSiTe3 and doped samples through flux growth, producing plate-like bulk crystals. Crystal quality was checked by x-ray diffraction and energy dispersive spectroscopy, and then thermal conductivity and magnetization measurements were obtained on the doped materials to compare variations from the pristine CrSiTe3.

  14. Thermal conduction study of warm dense aluminum by proton differential heating

    NASA Astrophysics Data System (ADS)

    Ping, Y.; Kemp, G.; McKelvey, A.; Fernandez-Panella, A.; Shepherd, R.; Collins, G.; Sio, H.; King, J.; Freeman, R.; Hua, R.; McGuffey, C.; Kim, J.; Beg, F.

    2016-10-01

    A differential heating platform has been developed for thermal conduction study (Ping et al. PoP 2015), where a temperature gradient is induced and subsequent heat flow is probed by time-resolved diagnostics. An experiment using proton differential heating has been carried out at Titan laser for Au/Al targets. Two single-shot time-resolved diagnostics are employed, SOP (streaked optical pyrometry) for surface temperature and FDI (Fourier Domain Interferometry) for surface expansion. Hydrodynamic simulations show that after 15ps, absorption in underdense plasma needs to be taken into account to correctly interpret SOP data. Comparison between simulations with different thermal conductivity models and a set of data with varying target thickness will be presented. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  15. Stratton Sagebrush Hydrology Study Area: An annotated bibliography of research conducted 1968-1990

    USGS Publications Warehouse

    Burgess, Leah M.; Schoenecker, Kathryn A.

    2004-01-01

    This annotated bibliography provides an overview of research projects conducted on the Stratton Sagebrush Hydrology Study Area (Stratton) since its designation as such in 1967. Sources include the Rocky Mountain Forest and Range Experiment Station records storage room, Laramie, Wyoming, the USGS and USFS online reference libraries, and scientific journal databases at the University of Wyoming and Colorado State University. This annotated bibliography summarizes publications from research conducted at Stratton during the prime of its tenure as a research lab from 1968 to 1990. In addition, an appendix is included that catalogues all data on file at the Rocky Mountain Forest and Range Experiment Station in Laramie, Wyoming. Each file folder was searched and its contents recorded here for the researcher seeking original data sets, charts, photographs and records.

  16. Compensated Arrhenius formalism applied to a conductivity study in poly(propylene glycol) diacrylate monomers

    NASA Astrophysics Data System (ADS)

    Dubois, F.; Derouiche, Y.; Leblond, J. M.; Maschke, U.; Douali, R.

    2015-09-01

    The temperature dependence of the ionic conductivity is studied in a series of poly(propylene glycol) diacrylate monomers. The experimental data are analyzed by means of the approach recently proposed by Petrowsky et al. [J. Phys. Chem. B. 113, 5996 (2009), 10.1021/jp810095g]. This so-called compensated Arrhenius formalism (CAF) approach takes into account the influence of the dielectric permittivity on the exponential prefactor in the classical Arrhenius equation. The experimental data presented in this paper show a good agreement with the CAF; this means that the exponential prefactor is principally dielectric permittivity dependent. The compensated data revealed two conduction processes with different activation energies; they correspond to low and high temperature ranges, respectively.

  17. Ballpoint pen ingestion in a 2-year-old child.

    PubMed

    Rameau, Anaïs; Anand, Sumeet M; Nguyen, Lily H

    2011-07-01

    A 2-year-old girl ingested a ballpoint pen, which was found on chest x-ray to have lodged in the lower esophagus and stomach. The pen, which measured nearly 15 cm in length, was removed via rigid esophagoscopy without complication. To the best of our knowledge, this is the longest nonflexible foreign body ingested by a young child ever reported in the English-language literature. We describe the presentation of this case and the current guidelines for safety as enumerated in the Small Parts Regulations established by the U.S. Consumer Product Safety Commission.

  18. Mixed ionic and electronic conducting electrode studies for an alkali metal thermal to electric converter

    NASA Astrophysics Data System (ADS)

    Guo, Yuyan

    This research focuses on preparation, kinetics, and performance studies of mixed ionic and electronic conducting electrodes (MIEE) applied in an alkali metal thermal to electric converter (AMTEC). Two types of MIEE, metal/sodium titanate and metal/beta″-alumina were investigated, using Ni, Cu, Co and W as the metal components. Pure metal electrodes (PME) were also studied, including Ta, Ni, Nb, Ir, W and MoRe electrodes. The stability of MIEE/beta″-alumina solid electrolyte (BASE) interface was studied in terms of the chemical potential of Na-Al-Ti-O system at 1100K (typical AMTEC operating temperature). Ni metal was compatible with sodium titanate and BASE and displayed the best initial performance among all tested PMEs. Ni/sodium titanate electrodes with 4/1 mass ratios of metal/ceramic performed best among all tested electrodes. Scanning Electron Microscope (SEM) observations showed that grain agglomeration, which is the main mechanism for electrode degradation, occurred in all tested electrodes. Ceramic components were able to effectively limit the growth of metal grains and resulted in a long lifetime for MIEEs. Ni particles in the MIEE formed a network microstructure that was close to the theoretical morphology of the ideal electrode. A model based on percolation theory was constructed to interpret and predict the performance of MIEEs. The electrode kinetics was studied and a theoretical expression for the interface impedance was derived for both PME and MIEE, using electrochemical impedance spectroscopy (EIS). The conductivity of the Na2Ti 3O7 and Na2Ti6O13 mixture was measured. The average activation energy for the bulk conductivity was 0.87ev. Finally, theoretical analysis clarified that the transfer coefficient alpha value change would cause at most a few percent change in the electrode performance parameter B.

  19. Promoting good clinical practices in the conduct of clinical trials: experiences in the Department of Veterans Affairs Cooperative Studies Program.

    PubMed

    Sather, Mike R; Raisch, Dennis W; Haakenson, Clair M; Buckelew, Julia M; Feussner, John R

    2003-10-01

    The ever-increasing concern for the welfare of volunteers participating in clinical trials and for the integrity of the data derived from those trials has generated the concept of Good Clinical Practice (GCP). The Veterans Affairs Cooperative Studies Program, in anticipation of the need to comply with GCP guidelines, developed a Site Monitoring and Review Team (SMART), which consists of a Good Clinical Practice Monitoring Group and a Good Clinical Practice Review Group. The review group conducted 335 site reviews from fiscal years (FY) 1999 through 2001 to assess and encourage adherence to GCP. Data from reviews were compared for two time periods, a 2-year implementation period (FYs 1999/2000, n=204) and a continuing follow-up period (FY 2001, n=131). Overall, high GCP adherence was exhibited by 11.3% (n=23) of study sites in FY 1999/2000 versus 20.6% (n=27) in FY 2001, average to good adherence was exhibited by 84.3% (n=172) in FY 1999/2000 versus 77.0% (n=101) in FY 2001, and below average adherence was exhibited by 4.4% (n=9) versus 1.5% (n=3) in these two periods. These changes were statistically significant by chi square analysis (p=0.029). Moreover, GCP adherence was assessed within eight GCP focus areas: patient informed consent, protocol adherence, safety monitoring, institutional review board interactions, regulatory document management, patient records in investigator file, drug/device accountability, and general site operations. Median assessment scores for all 62 GCP review elements improved from 0.82 to 0.89 (p<0.001). Median assessment scores for the 14 selected critical GCP items improved from 0.78 to 0.89 (p<0.001). Median scores for five of the eight GCP focus areas improved significantly (p<0.001) between the two time periods. These data suggest that the site-oriented activities of SMART combined with centralized quality assurance activities of the coordinating centers represent an integrated, versatile program to promote and assure GCP adherence

  20. Study of single-nucleotide polymorphisms by means of electrical conductance measurements

    NASA Astrophysics Data System (ADS)

    Hihath, Joshua; Xu, Bingqian; Zhang, Peiming; Tao, Nongjian

    2005-11-01

    Understanding the complexities of DNA has been a hallmark of science for over a half century, and one of the important topics in DNA research is recognizing the occurrence of mutations in the base-stack. In this article, we present a study of SNPs by direct-contact electrical measurements to a single DNA duplex. We have used short, 11- and 12-bp dsDNA to investigate the change in conductance that occurs if a single base pair, a single base, or two separate bases in the stack are modified. All measurements are carried out in aqueous solution with the DNA chemically bound to the electrodes. These measurements demonstrate that the presence of a single base pair mismatch can be identified by the conductance of the molecule and can cause a change in the conductance of dsDNA by as much as an order of magnitude, depending on the specific details of the double helix and the single nucleotide polymorphism. molecular electronics | scanning tunneling microscope break junction

  1. Computational Study of Subdural Cortical Stimulation: Effects of Simulating Anisotropic Conductivity on Activation of Cortical Neurons

    PubMed Central

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2015-01-01

    Subdural cortical stimulation (SuCS) is an appealing method in the treatment of neurological disorders, and computational modeling studies of SuCS have been applied to determine the optimal design for electrotherapy. To achieve a better understanding of computational modeling on the stimulation effects of SuCS, the influence of anisotropic white matter conductivity on the activation of cortical neurons was investigated in a realistic head model. In this paper, we constructed pyramidal neuronal models (layers 3 and 5) that showed primary excitation of the corticospinal tract, and an anatomically realistic head model reflecting complex brain geometry. The anisotropic information was acquired from diffusion tensor magnetic resonance imaging (DT-MRI) and then applied to the white matter at various ratios of anisotropic conductivity. First, we compared the isotropic and anisotropic models; compared to the isotropic model, the anisotropic model showed that neurons were activated in the deeper bank during cathodal stimulation and in the wider crown during anodal stimulation. Second, several popular anisotropic principles were adapted to investigate the effects of variations in anisotropic information. We observed that excitation thresholds varied with anisotropic principles, especially with anodal stimulation. Overall, incorporating anisotropic conductivity into the anatomically realistic head model is critical for accurate estimation of neuronal responses; however, caution should be used in the selection of anisotropic information. PMID:26057524

  2. A theoretical study of wave dispersion and thermal conduction for HMX/additive interfaces

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2014-04-01

    The wave dispersion rule for non-uniform material is useful for ultrasonic inspection and engine life prediction, and also is key in achieving an understanding of the energy dissipation and thermal conduction properties of solid material. On the basis of linear response theory and molecular dynamics, we derive a set of formulas for calculating the wave dispersion rate of interface systems, and study four kinds of interfaces inside plastic bonded explosives: HMX/{HMX, TATB, F2312, F2313}. (HMX: octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine; TATB: 1,3,5-triamino-2,4,6-trinitrobenzene; F2312, F2313: fluoropolymers). The wave dispersion rate is obtained over a wide frequency range from kHz to PHz. We find that at low frequency, the rate is proportional to the square of the frequency, and at high frequency, the rate couples with the molecular vibration modes at the interface. By using the results, the thermal conductivities of HMX/additive interfaces are derived, and a physical model is built for describing the total thermal conductivity of mixture explosives, including HMX multi-particle systems and {TATB, F2312, F2313}-coated HMX.

  3. Impact of vacancies on the thermal conductivity of graphene nanoribbons: A molecular dynamics simulation study

    NASA Astrophysics Data System (ADS)

    Noshin, Maliha; Khan, Asir Intisar; Navid, Ishtiaque Ahmed; Uddin, H. M. Ahsan; Subrina, Samia

    2017-01-01

    Equilibrium molecular dynamics simulation using 2nd generation Reactive Bond Order interatomic potential has been performed to model the thermal transport of nanometer sized zigzag defected graphene nanoribbons (GNRs) containing several types of vacancies. We have investigated the thermal conductivity of defected GNRs as a function of vacancy concentration within a range of 0.5% to 5% and temperature ranging from 300K to 600K, along with a comparative analysis of those for pristine GNRs. We find that, a vacancy concentration of 0.5% leads to over 90% reduction in the thermal conductivity of GNRs. At low defect concentration, the decay rate is faster but ceases gradually at higher defect concentration. With the increasing temperature, thermal conductivity of defected GNRs decreases but shows less variation in comparison with that of pristine GNRs at higher temperatures. Such comprehensive study on several vacancy type defects in GNRs can provide further insight to tune up the thermal transport characteristics of low dimensional carbon nanostructures. This eventually would encourage the characterization of more stable thermal properties in thermal devices at an elevated temperature as well as the potential applicability of GNRs as thermoelectrics.

  4. Defining components of the research process needed to conduct and critique studies.

    PubMed

    Summers, S

    1991-02-01

    The research process consists of a five-chapter approach. Chapters one through three are written during the planning stages of a study. Chapter one consists of problem, purpose, hypotheses or research questions, definitions, theoretical framework, and significance for nursing. Chapter two consists of the review of literature. Chapter three consists of the methodology: sample, setting, design, data analysis methods, and ethical concerns. Chapters four and five are written after the study is completed. Chapter four consists of results of data analysis. Chapter five consists of a discussion of results, conclusions, implications for nurses, and recommended future studies. It is important for nurses to review and apply this five-chapter approach when conducting or critiquing research studies.

  5. Thermal conductivity studies of novel nanofluids based on metallic silver decorated mesoporous silica nanoparticles

    SciTech Connect

    Tadjarodi, Azadeh; Zabihi, Fatemeh

    2013-10-15

    Graphical abstract: - Highlights: • Metallic silver was decorated in mSiO{sub 2} with grafted hemiaminal functional groups. • Synthesized nanoparticles were used for preparation of glycerol based nanofluids. • The effect of temperature, weight fraction of mSiO{sub 2} and concentration of silver nanoparticles on thermal conductivity of nanofluids was investigated. - Abstract: In the present study, the mesoporous structure of silica (mSiO{sub 2}) nanoparticles as well as hemiaminal grafted mSiO{sub 2} decorated by metallic silver (Ag/mSiO{sub 2}) has been used for the preparation of glycerol based nanofluids. Structural and morphological characterization of the synthesized products have been carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), UV–vis spectroscopy, inductively coupled plasma (ICP) and N{sub 2} adsorption–desorption isotherms. The thermal conductivity and viscosity of the nanofluids have been measured as a function of temperature for various weight fractions and silver concentrations of mSiO{sub 2} and Ag/mSiO{sub 2} nanoparticles, respectively. The results show that the thermal conductivity of the nanofluids increase up to 9.24% as the weight fraction of mSiO{sub 2} increases up to 4 wt%. Also, increasing the percent of the silver decorated mSiO{sub 2} (Ag/mSiO{sub 2}) up to 2.98% caused an enhancement in the thermal conductivity of the base fluid up to 10.95%. Furthermore, the results show that the nanofluids have Newtonian behavior in the tested temperature range for various concentrations of nanoparticles.

  6. A study of conductive hydrogel composites of pH-responsive microgels and carbon nanotubes.

    PubMed

    Cui, Zhengxing; Zhou, Mi; Greensmith, Paula J; Wang, Wenkai; Hoyland, Judith A; Kinloch, Ian A; Freemont, Tony; Saunders, Brian R

    2016-05-14

    Conductive gel composites are attracting considerable attention because of their interesting electrical and mechanical properties. Here, we report conductive gel composites constructed using only colloidal particles as building blocks. The composites were prepared from mixed dispersions of vinyl-functionalised pH-responsive microgel particles (MGs) and multi-walled carbon nanotubes (CNTs). MGs are crosslinked pH-responsive polymer colloid particles that swell when the pH approaches the pKa of the particles. Two MG systems were used which contained ethyl acrylate (EA) or methyl acrylate (MA) and around 30 mol% of methacrylic acid (MAA). The MA-based MG is a new pH-responsive system. The mixed MG/CNT dispersions formed thixotropic physical gels. Those gels were transformed into covalent interlinked electrically conducting doubly crosslinked microgel/CNT composites (DX MG/CNT) by free-radical reaction. The MGs provided the dual roles of dispersant for the CNTs and macro-crosslinker for the composite. TEM data showed evidence for strong attraction between the MG and the CNTs which facilitated CNT dispersion. An SEM study confirmed CNT dispersion throughout the composites. The mechanical properties of the composites were studied using dynamic rheology and uniaxial compression measurements. Surprisingly, both the ductility and the modulus of the gel composites increased with increasing CNT concentration used for their preparation. Human adipose-derived mesenchymal stem cells (AD-MSCs) exposed to DX MG/CNT maintained over 99% viability with metabolic activity retained over 7 days, which indicated non-cytotoxicity. The results of this study suggest that our approach could be used to prepare other DX MG/CNT gel composites and that these materials may lead to future injectable gels for advanced soft-tissue repair.

  7. Simultaneous Single Molecule Fluorescence and Conductivity Studies Reveal Distinct Classes of Aβ Species on Lipid Bilayers

    PubMed Central

    Schauerte, Joseph A.; Wong, Pamela T.; Wisser, Kathleen C.; Ding, Hao; Steel, Duncan G.; Gafni, Ari

    2010-01-01

    The extracellular senile plaques prevalent in brain tissue in Alzheimer's disease (AD) are composed of amyloid fibrils formed by the Aβ peptide. These fibrils have been traditionally believed to feature in neurotoxicity; however, numerous recent studies provide evidence that cytotoxicity in AD may be associated with low molecular weight oligomers of Aβ that associate with neuronal membranes and may lead to membrane permeabilization and disruption of the ion balance in the cell. The underlying mechanism leading to disruption of the membrane is the subject of many recent studies. Here we report the application of single molecule optical detection, using fluorescently labeled human Aβ40, combined with membrane conductivity measurements, to monitor the interaction of single oligomeric peptide structures with model planar black lipid membranes (BLM). In a qualitative study, we show that the binding of Aβ to the membrane can be described by three distinctly different behaviors, depending on the Aβ monomer concentration. For concentrations much below 10 nM, there is uniform binding of monomers over the surface of the membrane with no evidence of oligomer formation or membrane permeabilization. Between 10 nM and a few 100 nM, the uniform monomer binding is accompanied by the presence of peptide species ranging from dimers to small oligomers. The dimers are not found to permeabilize the membrane but the larger oligomers lead to permeabilization with individual oligomers producing ion conductances of less than 10 pS/pore. At higher concentration, perhaps beyond physiologically relevant concentrations, larger extended and dynamic structures are found with large conductance (100's of pS) suggesting major disruption of the membrane. PMID:20201586

  8. Enhanced ionic conductivity and optical studies of plasticized (PEO-KCl) solid polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    Solid polymer electrolytes (SPEs) based on Polyethylene oxide (PEO) doped with potassium chloride (KCl) were prepared by the solution cast technique. The conductivity increases from 10-10 to 10-6 Scm-1 at 303K with dopant. Optical absorption study shows that the direct & indirect optical band gaps were found decreased from 5.45-4.46eV and 4.96-3.86eV respectively with increasing the KCl. The XRD patterns reveal increasing the amorphous with increasing the dopent. The obtained results suggest that, these polymer systems are suitable candidates for solid state battery, electro chromic devices & optoelectronics display etc.

  9. Parametric Study of the Absorption Cross-Section for a Moderately Conducting Thin Cylinder.

    NASA Astrophysics Data System (ADS)

    Gurton, Kristan Peter

    A system has been developed to measure the absorption cross section of a single carbon fiber at 35 GHz as a function of length, orientation, and diameter. Typical lengths considered ranged from 1 to 20 mm, and diameters ranged from 3 to 8 um. The results were compared with the modified integral equation calculations of Waterman and Pedersen that describe the scattering and absorption behavior for a wire of finite length and conductivity. Good agreement was found for all lengths, orientations, and diameters studied.

  10. Parametric study of the absorption cross section for a moderately conducting thin cylinder

    NASA Astrophysics Data System (ADS)

    Gurton, Kristan P.; Bruce, Charles W.

    1995-05-01

    A system has been developed to measure the absorption cross section for a single carbon fiber at 35 GHz as a function of length, orientation, and diameter. Typical lengths of the fibers considered ranged from 1 to 20 mm, and diameters ranged from 3 to 8 mu m. The results were compared with the modified integral equation calculations of Waterman and Pedersen that describe the scattering and absorption behavior for a wire of finite length and conductivity. Good agreement was found for all lengths, orientations, and diameters studied.

  11. Structural and Conductivity Studies on Lanthanum Doped LiNiPO4 Prepared by Polyol Method

    NASA Astrophysics Data System (ADS)

    Karthickprabhu, S.; Hirankumar, G.; Maheswaran, A.; Bella, R. S. Daries; Sanjeeviraja, C.

    2013-07-01

    Pure and Lanthanum doped LiNiPO4 (with different Molar concentrations) have been prepared by polyol method using 1,2 propanediol as a polyol medium. XRD analysis reveal that sample calcined at 650°C for 6 hrs shows good crystalline nature with orthorhombic structure and this result is consistent with TG/DTA result. It is found that the conductivity enhances upon doping of Lanthanum while backhoprate decreases compared with pure LiNiPO4. Dielectric studies have also been discussed.

  12. Changing Network Support for Drinking: Network Support Project 2-Year Follow-up

    ERIC Educational Resources Information Center

    Litt, Mark D.; Kadden, Ronald M.; Kabela-Cormier, Elise; Petry, Nancy M.

    2009-01-01

    The Network Support Project was designed to determine whether a treatment could lead patients to change their social network from one that supports drinking to one that supports sobriety. This study reports 2-year posttreatment outcomes. Alcohol-dependent men and women (N = 210) were randomly assigned to 1 of 3 outpatient treatment conditions:…

  13. Japanese Female Students' Perceptions of 2-Year Colleges as a Choice for Postsecondary Education

    ERIC Educational Resources Information Center

    Anzai, Shinobu; Paik, Chie Matsuzawa

    2012-01-01

    Two-year colleges have played an important role in providing postsecondary education for women in postwar Japan. More recently, a dwindling college-bound population in Japan has resulted in a drastic decrease in the number of and enrollment in 2-year colleges. This study explored the motivations and aspirations of 12 Japanese female students to…

  14. Attitudes of College Students Enrolled in 2-Year Health Care Programs towards Online Learning

    ERIC Educational Resources Information Center

    Abdulla, Dalya

    2012-01-01

    Colleges offering 2-year diplomas to high-school graduates were among the forefront leaders in online learning however studies illustrating appropriate course construction for such student populations are scarce. Pharmacy Math (MATH16532) is a core course for students enrolled in the Practical Nursing (PN) and Pharmacy Technician (PT) programs at…

  15. Phonetic Modification of Vowel Space in Storybook Speech to Infants up to 2 Years of Age

    ERIC Educational Resources Information Center

    Burnham, Evamarie B.; Wieland, Elizabeth A.; Kondaurova, Maria V.; McAuley, J. Devin; Bergeson, Tonya R.; Dilley, Laura C.

    2015-01-01

    Purpose: A large body of literature has indicated vowel space area expansion in infant-directed (ID) speech compared with adult-directed (AD) speech, which may promote language acquisition. The current study tested whether this expansion occurs in storybook speech read to infants at various points during their first 2 years of life. Method: In 2…

  16. Persistence by 2-Year College Graduates to 4-Year Colleges and Universities.

    ERIC Educational Resources Information Center

    Dworkin, Stephen L.

    1996-01-01

    Presents findings from a study of the relationship between the characteristics of 3,762 Connecticut 2-year college students 25 or older and their persistence to 4-year colleges. Reports that students with higher perceptions of social and institutional support and those over 35 were more likely to persist to 4-year institutions. (10 citations) (AJL)

  17. Behavior Predictors of Language Development over 2 Years in Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Bopp, Karen D.; Mirenda, Pat; Zumbo, Bruno D.

    2009-01-01

    Purpose: This exploratory study examined predictive relationships between 5 types of behaviors and the trajectories of vocabulary and language development in young children with autism over 2 years. Method: Participants were 69 children with autism assessed using standardized measures prior to the initiation of early intervention (T1) and 6 months…

  18. Emotionally Focused Interventions for Couples with Chronically Ill Children: A 2-Year Follow-Up

    ERIC Educational Resources Information Center

    Cloutier, Paula F.; Manion, Ian G.; Walker, Jan Gordon; Johnson, Susan M.

    2002-01-01

    Couples with chronically ill children are particularly at risk for experiencing marital distress. The study presented here is a 2-year follow-up of a randomized control trial that assessed the efficacy of Emotionally Focused Therapy (EFT) in decreasing marital distress in a sample of couples with a chronically ill child. Thirteen couples with…

  19. How Are 2-Year US Colleges Addressing Student Alcohol Use and Related Problems?

    ERIC Educational Resources Information Center

    Lenk, Kathleen M.; Nelson, Toben F.; Erickson, Darin J.; Toomey, Traci L.

    2015-01-01

    A considerable amount of attention and research has been dedicated to addressing alcohol use and related problems among students at 4-year colleges; however, less attention has been given to alcohol-related issues among students at 2-year technical/community colleges. This article describes research that expands on a study by Chiauzzi and…

  20. How Joint Attention Relates to Cooperation in 1- and 2-Year-Olds

    ERIC Educational Resources Information Center

    Wu, Zhen; Pan, Jingtong; Su, Yanjie; Gros-Louis, Julie

    2013-01-01

    Joint attention has been suggested to contribute to children's development of cooperation; however, few empirical studies have directly tested this hypothesis. Children aged 1 and 2 years participated in two joint action activities to assess their cooperation with an adult partner, who stopped participating at a specific moment during the tasks.…

  1. Common Aetiology for Diverse Language Skills in 4 1/2-Year-Old Twins

    ERIC Educational Resources Information Center

    Hayiou-Thomas, Marianna E.; Kovas, Yulia; Harlaar, Nicole; Plomin, Robert; Bishop, Dorothy V. M.; Dale, Philip S.

    2006-01-01

    Multivariate genetic analysis was used to examine the genetic and environmental aetiology of the interrelationships of diverse linguistic skills. This study used data from a large sample of 4 1/2-year-old twins who were tested on measures assessing articulation, phonology, grammar, vocabulary, and verbal memory. Phenotypic analysis suggested two…

  2. The Validity of Graduate Management Admission Test Scores: A Summary of Studies Conducted from 1997 to 2004

    ERIC Educational Resources Information Center

    Talento-Miller, Eileen; Rudner, Lawrence M.

    2008-01-01

    The validity of Graduate Management Admission Test (GMAT) scores is examined by summarizing 273 studies conducted between 1997 and 2004. Each of the studies was conducted through the Validity Study Service of the test sponsor and contained identical variables and statistical methods. Validity coefficients from each of the studies were corrected…

  3. Study of correlations between microstructure and conductivity in a thermoplastic polyurethane electrolyte

    SciTech Connect

    Furtado, C.A.

    1999-08-26

    Micro-Raman and positron annihilation lifetime spectroscopy (PALS) have been used to investigate the structure of a thermoplastic polyurethane/LiClO{sub 4} solid flexible polymer electrolyte at room temperature. Correlation between the free volume and carrier concentration with ionic conductivity was observed. The polyurethane soft phase consisted of a poly(tetramethylene glycol-co-ethylene glycol) copolymer reinforced by condensation with hexamethyldiisocianate. The range of salt concentration between 5 and 35 wt %, which attained the beginning of phase segregation, was also studied by differential scanning calorimetry (DSC), which showed the presence of three thermal events; the soft-phase T{sub g}, a change in heat capacity suggested as the hard-phase T{sub g}, and a hard-phase ordering endotherm. The total ionic conductivity was found to be approximately 4 {times} 10{sup {minus}6} S cm{sup {minus}1} at 23 C up to 27 wt % salt, whereas there were pronounced changes observed by the spectroscopic techniques. The PALS measurements indicated a decrease of 40% of the ratio (V{sub f}I{sub 3}/(V{sub f}I{sub 3}){sub 0}) between the free volume parameters probed by the positron particle. This ratio is proportional to the fractional free volume of the system. The micro-Raman results showed an increase of ionic aggregation, although the charge carrier concentration increased significantly in the range of compositions studied. The opposite effects of the microstructural changes and the maximum conductivity value, in the observed range of concentrations, are discussed.

  4. Asymptomatic rhythm and conduction abnormalities in children with acute rheumatic fever: 24-hour electrocardiography study.

    PubMed

    Karacan, Mehmet; Işıkay, Sedat; Olgun, Haşim; Ceviz, Naci

    2010-12-01

    Some rhythm and conduction abnormalities can occur in children with acute rheumatic fever. These abnormalities have been defined based on standard electrocardiography; however, the real prevalence of these abnormalities has not been investigated previously by the evaluation of long-term electrocardiographic recordings. In this study, we evaluated the asymptomatic rhythm and conduction abnormalities in children with acute rheumatic fever by evaluating the 24-hour electrocardiography. We evaluated the standard electrocardiography and the 24-hour electrocardiography of 64 children with acute rheumatic fever. On standard electrocardiography, the frequency of the first-degree atrioventricular block was found to be 21.9%. Electrocardiography at 24 hours detected three additional and separate patients with a long PR interval. Mobitz type I block and atypical Wenckebach periodicity were determined in one patient (1.56%) on 24-hour electrocardiography. While accelerated junctional rhythm was detected in three patients on standard electrocardiography, it was present in nine patients according to 24-hour electrocardiography. Premature contractions were present in 1.7% of standard electrocardiography, but in 29.7% of 24-hour electrocardiography. Absence of carditis was found to be related to the presence of accelerated junctional rhythm (p > 0.05), and the presence of carditis was found to be related to the presence of premature contractions (p = 0.000). In conclusion, our results suggest that in children with acute rheumatic fever, the prevalence of rhythm and conduction abnormalities may be much higher than determined on standard electrocardiography. Further studies are needed to clarify whether or not these abnormalities are specific to acute rheumatic fever.

  5. Depressive and anxiety disorders: Associated with losing or gaining weight over 2 years?

    PubMed

    de Wit, Leonore M; van Straten, Annemieke; Lamers, Femke; Cuijpers, Pim; Penninx, Brenda W J H

    2015-06-30

    This longitudinal study examines to what extent different depressive and anxiety disorders and clinical characteristics are associated with subsequent weight change, while controlling for baseline weight, sociodemographics, health status, psychotropic medication use and (un)healthy lifestyle factors. Data are from a sample of 2447 respondents aged 18-65 years of the Netherlands Study of Depression and Anxiety (NESDA). Baseline depressive disorders and anxiety disorders were determined with the Composite International Diagnostic Interview (CIDI). Weight at baseline and after 2 years was measured and analyzed as continuous change score (mean change in weight 1kg) and in categories of significant weight loss (<1S.D. weight change equaling <4kg), weight maintenance and weight gain (>1S.D., >6kg). After full adjustment for covariates baseline comorbid anxiety and depressive disorder and baseline Major Depressive Disorder (MDD) were associated with significant 2-year weight gain. Both current and remitted MDD at baseline and a baseline dysthymia, but none of the anxiety disorders, were associated with significant weight loss. This longitudinal study confirms a U-curved link between depression and weight change over 2 years. Furthermore, a dose-response effect of depression severity on 2-year weight gain was found.

  6. Electrical and Nonlinear Optical Studies of Specific Organic Molecular and Nonconjugated Conductive Polymeric Systems

    NASA Astrophysics Data System (ADS)

    Narayanan, Ananthakrishnan

    In this research, structural, electrical and nonlinear optical characteristics of: (a) single crystal films involving a noncentrosymmetric molecule DAST and a laser dye IR125 and (b) specific nonconjugated conducting polymers including poly(beta-pinene) and polynorbornene have been studied. 4'-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) is a well known second order nonlinear optical material. This material has exceptionally high electro-optic coefficients, high thermal stability and ultrafast response time. In this work single crystal films involving a combination of DAST and IR125 have been prepared using modified shear method and the films have been characterized using polarized optical microscopy, X-ray diffraction, polarization dependent optical absorption and photoluminescence spectroscopy. The electro-optic coefficient of these films measured at 633nm was found to be 300pm/V. Since IR-125 has a strong absorption band from 500nm to 800nm, these films are promising for various applications in nonlinear optics at longer wavelength and for light emission. Nonconjugated conducting polymers are a class of polymers that have at least one double bond in their repeat units. 1,4-cis polyisoprene, polyalloocimene, styrene butadiene rubber, poly(ethylenepyrrolediyl) derivatives, and poly(beta-pinene) are some of the well known examples of nonconjugated conducting polymers. In this work, polynorborne, a new addition to the class of nonconjugated conducting polymers is discussed. Like other polymers in this class, polynorbornene exhibits increase in electrical conductivity by many orders of magnitude upon doping with iodine. The maximum electrical conductivity of this material is 0.01 S/cm. As shown by using FTIR microscopy, the C=C bonds are transformed into cation radicals when polynorborne is doped. This is due to the charge-transfer from the double bond to the dopant (iodine). These materials like other nonconjugated conducting polymers have significant

  7. A phonological system at 2 years after cochlear implantation

    PubMed Central

    CHIN, STEVEN B.; PISONI, DAVID B.

    2011-01-01

    This report is a description of a developing phonological system as manifested in the productions of a prelingually deafened child approximately 2 years after fitting with a Nucleus 22-Channel Multi-Electrode Cochlear Implant. A probe list consisting of 23 proper nouns familiar to the child was used to elicit samples of her speech; stimulus materials consisted of photographs of those persons (friends and family members) whose names were included in the probe list. Analysis of the child's productions addressed the composition of the phonetic inventory of consonants and vowels and the presence of syllable structure and other phonotactic constraints. Results indicated a rich inventory of speech sound segments (among both consonants and vowels) and a lack of stringent constraints on syllable structure and consonants permitted in specified word positions. A further comparative analysis of correspondences with the ambient language showed a number of patterns that are also common in the speech of children with normal hearing. PMID:22091697

  8. The potential influence of Internet-based social networking on the conduct of clinical research studies.

    PubMed

    Glickman, Seth W; Galhenage, Sam; McNair, Lindsay; Barber, Zachry; Patel, Keyur; Schulman, Kevin A; McHutchison, John G

    2012-02-01

    The rapid growth of internet usage has led to an explosion of social networking sites for discussion of health issues. This provides a forum for subjects to communicate with one another during the course of the studies. Previous studies have raised concerns about the quality of health information on social networking sites, although none have evaluated content related to ongoing clinical trials. We reviewed material posted in virtual communities by self-identified clinical trial participants. We identified material posted in online health forums that could introduce bias into clinical research studies; we believe that this issue warrants further study and discussion. Physicians and others who conduct clinical trials should be aware of this issue. Study investigators and research teams should also talk to their study subjects about where and how they are obtaining information in order to prevent behaviors and correct misinformation that could put a subject's safety or the study objectives at risk. Given the rapid increase in Internet use for health care, a broader evaluation of both the benefits and potential risks of social networking among research participants during the course of a clinical trial appears warranted.

  9. [Physiological approach to peripheral neuropathy. Conventional nerve conduction studies and magnetic motor root stimulation].

    PubMed

    Ugawa, Yoshikazu

    2004-11-01

    In this communication, I first show some points we should mind in the conventional peripheral nerve conduction studies and later present clinical usefulness of motor root stimulation for peripheral neuropathy. CONVENTIONAL NERVE CONDUCTION STUDIES (NCS): The most important point revealed by the conventional NCSs is whether neuropathy is due to axonal degeneration or demyelinating process. Precise clinical examination with this neurophysiological information leads us to a diagnosis and treatment. Poor clinical examination makes these findings useless. Long standing axonal degeneration sometimes induces secondary demyelination at the most distal part of involved nerves. On the other hand, severe segmental demyelination often provokes secondary axonal degeneration at distal parts to the site of demyelination. These secondary changes show the same abnormal neurophysiological findings as those of the primary involvement. We should be careful of this possibility when interpreting the results of NCS. NCS of sensory nerves is not good at revealing demyelinating process. Mild temporal dispersion of potentials often reduces an amplitude of SNAP or loss of responses, which usually suggests axonal degeneration, because of short duration of sensory nerve potentials. MOTOR ROOT STIMULATION IN PERIPHERAL NEUROPATHY: Magnetic stimulation with a coil placed over the spine activates motor roots and evokes EMG responses from upper and lower limb muscles. The site of activation with this method was determined to be where the motor roots exit from the spinal canal (intervertebral foramina) (J Neurol Neurosurg Psychiatry 52 (9): 1025-1032, 1989) because induced currents are very dense at such a foramen made by electric resistant bones. In several kinds of peripheral neuropathy, this method has been used to detect a lesion at a proximal part of the peripheral nerves which can not be detected by the conventional NCSs. I present a few cases in whom motor root stimulation had a clinical

  10. The first BETS radical cation salts with dicyanamide anion: Crystal growth, structure and conductivity study

    SciTech Connect

    Kushch, N.D.; Buravov, L.I.; Chekhlov, A.N.; Spitsina, N.G.; Kushch, P.P.; Yagubskii, E.B.; Herdtweck, E.; Kobayashi, A.

    2011-11-15

    Electrochemical oxidation of bis(ethylenedithio)tetraselenafulvalene (BETS) has been investigated. Simple and complex dicyanamides of transition metals (Mn{sup 2+}, Ni{sup 2+} and Fe{sup 2+}) were used as electrolytes. The correlation between composition of prepared radical cation salts and metal nature in electrolytes was established. Manganese dicyanamides provide the formation of BETS salts with the {l_brace}Mn[N(CN){sub 2}]{sub 3}{r_brace}- and [N(CN){sub 2}]-XH{sub 2}O anions. When Ni- or Fe-containing electrolytes were used only metalless BETS salts, {alpha}''-BETS{sub 2}[N(CN){sub 2}].2H{sub 2}O (I) and {theta}-BETS{sub 2}[N(CN){sub 2}].3.6H{sub 2}O (II), formed. Structures and conducting properties of these salts were analyzed. Both salts exhibit layered structure. Conducting radical cation layers have {alpha}'' (I)- or {theta}-type (II). Anion sheets appear as two-dimensional polymer networks of different types. These networks are formed by [N(CN)]{sub 2}{sup -} anions and water molecules interlinked by hydrogen bonds. Salt I is a semiconductor and II demonstrates resistance drop down to150 K at normal pressure and down to 72 K at {approx}0.4 kbar pressure. - Graphical abstract: We studied electrochemical oxidation of BETS donor in the presence of simple and/or complex dicyanamides of transition metals (Ni, Fe, Mn) as electrolytes. New conducting salts {alpha}''-BETS{sub 2}[N(CN){sub 2}].2H{sub 2}O and {theta}-BETS{sub 2}[N(CN){sub 2}].3.8H{sub 2}O have been synthesized and characterized. Highlights: > We studied electrochemical oxidation of BETS donor. > Dicyanamides of transition metals (Ni, Fe, Mn) were used as electrolytes. > We found a well-reproducible synthesis of magnetic superconductor BETS{sub 2}Mn[N(CN){sub 2}]{sub 3}. > Two new metalless BETS salts form when Ni and Fe electrolytes were used. > Their structure and conductivity were investigated.

  11. Prospective multicenter assessment of perioperative and minimum 2-year postoperative complication rates associated with adult spinal deformity surgery.

    PubMed

    Smith, Justin S; Klineberg, Eric; Lafage, Virginie; Shaffrey, Christopher I; Schwab, Frank; Lafage, Renaud; Hostin, Richard; Mundis, Gregory M; Errico, Thomas J; Kim, Han Jo; Protopsaltis, Themistocles S; Hamilton, D Kojo; Scheer, Justin K; Soroceanu, Alex; Kelly, Michael P; Line, Breton; Gupta, Munish; Deviren, Vedat; Hart, Robert; Burton, Douglas C; Bess, Shay; Ames, Christopher P

    2016-07-01

    OBJECTIVE Although multiple reports have documented significant benefit from surgical treatment of adult spinal deformity (ASD), these procedures can have high complication rates. Previously reported complications rates associated with ASD surgery are limited by retrospective design, single-surgeon or single-center cohorts, lack of rigorous data on complications, and/or limited follow-up. Accurate definition of complications associated with ASD surgery is important and may serve as a resource for patient counseling and efforts to improve the safety of patient care. The authors conducted a study to prospectively assess the rates of complications associated with ASD surgery with a minimum 2-year follow-up based on a multicenter study design that incorporated standardized data-collection forms, on-site study coordinators, and regular auditing of data to help ensure complete and accurate reporting of complications. In addition, they report age stratification of complication rates and provide a general assessment of factors that may be associated with the occurrence of complications. METHODS As part of a prospective, multicenter ASD database, standardized forms were used to collect data on surgery-related complications. On-site coordinators and central auditing helped ensure complete capture of complication data. Inclusion criteria were age older than 18 years, ASD, and plan for operative treatment. Complications were classified as perioperative (within 6 weeks of surgery) or delayed (between 6 weeks after surgery and time of last follow-up), and as minor or major. The primary focus for analyses was on patients who reached a minimum follow-up of 2 years. RESULTS Of 346 patients who met the inclusion criteria, 291 (84%) had a minimum 2-year follow-up (mean 2.1 years); their mean age was 56.2 years. The vast majority (99%) had treatment including a posterior procedure, 25% had an anterior procedure, and 19% had a 3-column osteotomy. At least 1 revision was required in 82

  12. Synthesis, Spectroscopic, ac Conductivity and Thermal Studies on Co(III) Acetylacetonate-Iodine Complex

    NASA Astrophysics Data System (ADS)

    Hashem, H. A.; Refat, M. S.

    A spectrophotometric study of 1:1 donor-acceptor complex, cobalt (III) acetylacetonate (donor) and iodine (σ-acceptor) has been preformed. The equilibrium constants, (K) and the absorpitivity (ɛ) for the formation of the iodine complex have been calculated. The predicted structure of the solid triiodide charge-transfer complex reported in this study is further supported by thermal, far and mid infrared spectroscopic measurements. Electron transfer from Co (acac = 2, 4-pentanedionate)3 to iodine leads to the formation of an organic semiconductor with the formula of [Co(acac)3]_2 I+. I3-. The kinetic parameters (nonisothermal method) for their decomposition have been evaluated by graphical methods using the equations of Freeman-Carroll (FC), Horowitz-Metzger (HM) and Coats-Redfern (CR). The ac conductivity and dielectric properties of [Co(acac)3]_2 I+. I3- have been measured over the frequency 50-106 Hz at temperature 298 K.

  13. 43 CFR 404.19 - What requirements must be met before I can request assistance to conduct a feasibility study?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... request assistance to conduct a feasibility study? 404.19 Section 404.19 Public Lands: Interior... a feasibility study? All of the following requirements must be met before you can request assistance to conduct a feasibility study: (a) An appraisal investigation must be completed, with or...

  14. Mechanism of Origin of Conduction Disturbances in Aging Human Atrial Bundles: Experimental and Model Study

    PubMed Central

    Spach, Madison S.; Heidlage, J. Francis; Dolber, Paul C.; Barr, Roger C.

    2007-01-01

    BACKGROUND Aging is associated with a significant increase in atrial tachyarrhythmias, especially atrial fibrillation. A macroscopic repolarization gradient created artificially by a stimulus at one site prior to a premature stimulus from a second site is widely considered to be part of the experimental protocol necessary for the initiation of such arrhythmias in the laboratory. How such gradients occur naturally in aging atrial tissue has remained unknown. OBJECTIVE This study was to determine if the pattern of cellular connectivity in aging human atrial bundles produces a mechanism for variable early premature responses. METHODS Extracellular and intracellular potentials were recorded following control and premature stimuli at a single site in aging human atrial bundles. We also measured cellular geometry, the distribution of connexins, and the distribution of collagenous septa. A model of the atrial bundles was constructed based on the morphological results. Action potential propagation and the sodium current were analyzed following premature stimuli in the model. RESULTS Similar extracellular potential waveform responses occurred following early premature stimuli in the aging bundles and in the model. Variable premature conduction patterns were accounted for by the single model of aging atrial structure. A major feature of the model results was that the conduction events and the magnitude of the sodium current at multiple sites were very sensitive to small changes in the location and the timing of premature stimuli. CONCLUSION In aging human atrial bundles stimulated from only a single site, premature stimuli induce variable arrhythmogenic conduction responses. The generation of these responses is greatly enhanced by remodeling of cellular connectivity during aging. The results provide insight into sodium current-structural interactions as a general mechanism of arrhythmogenic atrial responses to premature stimuli. PMID:17275753

  15. Sponsors’ participation in conduct and reporting of industry trials: a descriptive study

    PubMed Central

    2012-01-01

    Background Bias in industry-sponsored trials is common and the interpretation of the results can be particularly distorted in favour of the sponsor’s product. We investigated sponsors’ involvement in the conduct and reporting of industry-sponsored trials. Methods We included all industry-sponsored trials published in The Lancet in 2008 and 2009 and corresponding trial protocols provided by The Lancet. For each protocol and publication, we extracted information on trial conduct and reporting. Results We identified 169 publications of randomised trials and included 69 (41%) that were industry-sponsored, and 12 (7%) industry-funded but seemingly independently conducted as a subsample. Entry of data into the study database was done independently by academic authors without the involvement of the sponsor or a contract research organisation in one of the 69 trials. Two trials had independent data analysis and one independent reporting of results. In 11 of the trials, there was a discrepancy between the information in the protocols and papers concerning who analysed the data. In four of the 12 seemingly independent trials, the protocol described sponsors’ involvement in writing the report while the published paper explicitly stated that the sponsor was not involved. Conclusions The sponsors are usually involved in the analysis and reporting of results in industry-sponsored trials, but their exact role is not always clear from the published papers. Journals should require more transparent reporting of the sponsors’ role in crucial elements such as data processing, statistical analysis and writing of the manuscript and should consider requiring access to trial protocols, independent data analysis and submission of the raw data. PMID:22920226

  16. Myopia Control with a Novel Peripheral Gradient Soft Lens and Orthokeratology: A 2-Year Clinical Trial

    PubMed Central

    Pauné, Jaime; Morales, Hari; Armengol, Jesús; Quevedo, Lluisa; Faria-Ribeiro, Miguel; González-Méijome, José M.

    2015-01-01

    Objective. To evaluate the degree of axial elongation with soft radial refractive gradient (SRRG) contact lenses, orthokeratology (OK), and single vision (SV) spectacle lenses (control) during a period of 1 year before treatment and 2 years after treatment. Methods. This was a prospective, longitudinal, nonrandomized study. The study groups consisted of 30, 29, and 41 children, respectively. The axial length (AL) was measured during 2 years after recruitment and lens fitting. Results. The baseline refractive sphere was correlated significantly (Spearman's Rho (ρ) correlation = 0.542; P < 0.0001) with the amount of myopia progression before baseline. After 2 years, the mean myopia progression values for the SRRG, OK, and SV groups were −0.56 ± 0.51, −0.32 ± 0.53, and −0.98 ± 0.58 diopter, respectively. The results represent reductions in myopic progression of 43% and 67% for the SRRG and OK groups, respectively, compared to the SV group. The AL increased 27% and 38% less in the SRRG and OK groups, respectively compared with the SV group at the 2-year visit (P < 0.05). Axial elongation was not significantly different between SRRG and OK (P = 0.430). Conclusion. The SRRG lens significantly decreased AL elongation compared to the SV control group. The SRRG lens was similarly effective to OK in preventing myopia progression in myopic children and adolescent. PMID:26605331

  17. Ion transport study in polymer-nanocomposite films by dielectric spectroscopy and conductivity scaling

    NASA Astrophysics Data System (ADS)

    Tripathi, Namrata; Thakur, Awalendra K.; Shukla, Archana; Marx, David T.

    2015-07-01

    The dielectric and conductivity response of polymer nanocomposite electrolytes (films of PMMA4LiClO4 dispersed with nano-CeO2 powder) have been investigated. The dielectric behavior was analyzed via the dielectric permittivity (ε‧) and dissipation factor (tan δ) of the samples. The analysis has shown the presence of space charge polarization at lower frequencies. The real part of ac conductivity spectra of materials obeys the Jonscher power law. Parameters such as dc conductivity, hopping rate, activation energies and the concentration of charge carriers were determined from conductivity data using the Almond West formalism. It is observed that the higher ionic conductivity at higher temperature is due to increased thermally-activated hopping rates accompanied by a significant increase in carrier concentration. The contribution of carrier concentration to the total conductivity is also confirmed from activation energy of migration conduction and from Summerfield scaling. The ac conductivity results are also well correlated with TEM results.

  18. IN-SERVICE HYDRAULIC CONDUCTIVITY OF GCLS IN LANDFILL COVERS - LABORATORY AND FIELD STUDIES

    EPA Science Inventory

    Laboratory experiments using multi-species inorganic solutions (containing calcium and sodium) were conducted on specimens of a new geosynthetic clay liner (GCL) containing sodium bentonite to determine how cation exchange and desiccation affected the hydraulic conductivity. Calc...

  19. Study of poly (3-hexylthiophene) conducting polymer thin film micro-sensor for hydrazine vapor detection

    NASA Astrophysics Data System (ADS)

    Yang, Hong

    This dissertation discussed the construction and investigation of a poly (3-hexylthiophene) conducting polymer based thin film micro-sensor for a real-time detection of hydrazine vapor at ambient pressure. A type of low cost, small size, passive poly (3-hexylthiophene) thin film micro-sensor was designed and fabricated. The micro-sensor platform consisted of a rectangular shaped inert substrate and gold interdigited electrode pairs. A layer of poly (3-hexylthiophene) thin film was coated onto the sensor platform using a spin coating method, and nitrosonium hexafluorophosphate (NOPF6) was used to dope the poly (3-hexylthiophene) thin film to increase its electrical conductivity and form the finished sensor. The basic responses of the sensor to hydrazine vapor were experimentally investigated. The primary results showed that the sensor responded to hydrazine vapor in less than a few seconds; attained orders of magnitude change in normalized resistance during hydrazine exposure, and was not easily saturated. The interaction between the hydrazine gas molecules and doped poly (3-hexylthiophene) thin film was studied. The plausible mechanism was determined as: Charge carriers inside the doped poly (3-hexylthiophene) thin film were depleted during the oxidation-reduction chemical reaction between the hydrazine vapor and polymer film, resulting a reduction in the polymer film's electrical conductivity. Experiments were also conducted to find out the effects of hydrazine concentration, poly (3-hexylthiophene) thin film thickness, sensor storage time, environment temperature, and environment humidity on the sensor's performance. The response rate of the sensor under different sensing conditions was calculated and discussed. A diffusion-reaction model was applied to simulate the interaction between hydrazine molecules and doped poly (3-hexylthiophene) thin film. The profiles of hydrazine gas diffusion and positive charge carrier neutralization in the polymer film were

  20. Application of the thermoelectric phenomena to study the unsteady-state thermal conductivity

    NASA Astrophysics Data System (ADS)

    Poprawski, W.; Radojewska, E. B.

    2016-09-01

    We present an experimental set-up designed to investigate the unsteady-state thermal conductivity. A sine-shaped thermal wave is produced by a thermoelectric device and the change in temperature at two points in a metal rod is measured. The investigation is carried out for seven thermal wave frequencies. The thermal wave penetration depth and the thermal conductivity are determined by two methods: from the wave amplitude ratio and from the wave phase shift at two locations. The presented system also offers a determination of the thermal wave propagation velocity and the thermal diffusivity coefficient of the medium. The obtained measurement results are discussed. The specification of the measurement system is preceded by a theoretical and comprehensive description of the phenomena taking part in the experiment. With regard to the role of thermoelectric phenomena in contemporary science and technology the presented experiment is suitable for students in university laboratories studying metrology, electronics, space technology, energy harvesting, energo-mechanics, renewable energy science, chemical technology, bio-engineering and other similar courses.

  1. Quantum molecular dynamics study on the structures and dc conductivity of warm dense silane

    NASA Astrophysics Data System (ADS)

    Sun, Huayang; Kang, Dongdong; Dai, Jiayu; Zeng, Jiaolong; Yuan, Jianmin

    2014-02-01

    The ionic and electronic structures of warm dense silane at the densities of 1.795, 2.260, 3.382, and 3.844 g/cm3 have been studied with temperatures from 1000 K to 3 eV using quantum molecular dynamics simulations. At all densities, the structures are melted above 1000 K. The matter states are characterized as polymeric from 1000 to 4000 K and become dense plasma states with further increasing temperature to 1 eV. At two lower densities of 1.795 and 2.260 g/cm3, silane first dissociates and then becomes the polymeric state via a chain state from the initial crystalline structure. At higher densities, however, no dissociation stage was found. These findings can help us understand how the warm dense matter forms. A rise is found for the direct current electric conductivity at T ˜1000 K, indicating the nonmetal-to-metal transition. The conductivity decreases slightly with the increase of temperature, which is due to the more disordered structures at higher temperatures.

  2. Computational study on hole conduction in normal alkanes: Anisotropy and effect of dynamic disorder

    NASA Astrophysics Data System (ADS)

    Sato, M.; Kumada, A.; Hidaka, K.; Hirano, T.; Sato, F.

    2017-02-01

    Despite its importance, carrier conduction in electrical insulators is poorly understood. This work presents a computational study of hole conduction in single crystalline alkanes (n-C18H38 and n-C36H74). Hole mobilities are computed with the combination of molecular dynamics simulation, quantum chemical calculation, and the kinetic Monte Carlo method. The hole hopping rate is computed by the Fermi golden rule rate kernel without high temperature approximation. A strong correlation between the anisotropy of hole mobility and crystalline morphology is found. Hole mobilities in the direction of the c axis are more than an order of magnitude larger than those in the a - b plane. At room temperature, hole mobility is increased by roughly a factor of 10 due to the thermal motion of molecules. Computed anisotropic hole mobilities are in reasonable agreement with experimental values when the effect of dynamic disorder is taken into account. The results strongly indicate that hole transfer in crystalline alkane occurs in the phonon-assisted transport regime.

  3. Lead retention mechanisms and hydraulic conductivity studies of various bentonites for geoenvironment applications.

    PubMed

    Nakano, A; Li, L Y; Ohtsubo, M; Mishra, A K; Higashi, T

    2008-05-01

    Four bentonites from various sources were exposed to batch adsorption testing, selective sequential extraction and consolidation tests to investigate their metal retention capacity and hydraulic conductivity for geoenvironmental application such as in clay barrier materials. The Japanese bentonites (JB1-JB3) contain approximately 2-4% of carbonate and trace amount of zeolite (JB2 and JB3), whereas the US bentonite has < 1% carbonate and no zeolite. The rank of smectite content in the bentonites are USB > JB1 > JB3 > JB2. The materials ranked as JB2 approximately JB3 > JB1 > USB, according to retention capacity, while after the removal of carbonate the retention capacity order was JB1 approximately JB2 approximately JB3 > USB. SSE results indicate that carbonate plays a major role at low Pb solution concentration and precipitate as PbCO3. Once the carbonate is exhausted, the clay composition dominates the sorption process. The hydraulic conductivity of the bentonite mixtures (basalt + 10% bentonite) using water was kUSB < kJB1 < kJB3 < kJB2, consistent with the smectite content and swelling power, with USB having the highest proportion of smectite. Among the Japanese bentonites studied, JB1 is the best candidate for barrier material, comparable to the widely used USB.

  4. Density functional theory and conductivity studies of boron-based anion receptors

    DOE PAGES

    Leung, Kevin; Chaudhari, Mangesh I.; Rempe, Susan B.; ...

    2015-07-10

    Anion receptors that bind strongly to fluoride anions in organic solvents can help dissolve the lithium fluoride discharge products of primary carbon monofluoride (CFx) batteries, thereby preventing the clogging of cathode surfaces and improving ion conductivity. The receptors are also potentially beneficial to rechargeable lithium ion and lithium air batteries. We apply Density Functional Theory (DFT) to show that an oxalate-based pentafluorophenyl-boron anion receptor binds as strongly, or more strongly, to fluoride anions than many phenyl-boron anion receptors proposed in the literature. Experimental data shows marked improvement in electrolyte conductivity when this oxalate anion receptor is present. The receptor ismore » sufficiently electrophilic that organic solvent molecules compete with F– for boron-site binding, and specific solvent effects must be considered when predicting its F– affinity. To further illustrate the last point, we also perform computational studies on a geometrically constrained boron ester that exhibits much stronger gas-phase affinity for both F– and organic solvent molecules. After accounting for specific solvent effects, however, its net F– affinity is about the same as the simple oxalate-based anion receptor. Lastly, we propose that LiF dissolution in cyclic carbonate organic solvents, in the absence of anion receptors, is due mostly to the formation of ionic aggregates, not isolated F– ions.« less

  5. Density functional theory and conductivity studies of boron-based anion receptors

    SciTech Connect

    Leung, Kevin; Chaudhari, Mangesh I.; Rempe, Susan B.; Fenton, Kyle R.; Pratt, III, Harry D.; Staiger, Chad L.; Nagasubramanian, Ganesan

    2015-07-10

    Anion receptors that bind strongly to fluoride anions in organic solvents can help dissolve the lithium fluoride discharge products of primary carbon monofluoride (CFx) batteries, thereby preventing the clogging of cathode surfaces and improving ion conductivity. The receptors are also potentially beneficial to rechargeable lithium ion and lithium air batteries. We apply Density Functional Theory (DFT) to show that an oxalate-based pentafluorophenyl-boron anion receptor binds as strongly, or more strongly, to fluoride anions than many phenyl-boron anion receptors proposed in the literature. Experimental data shows marked improvement in electrolyte conductivity when this oxalate anion receptor is present. The receptor is sufficiently electrophilic that organic solvent molecules compete with F for boron-site binding, and specific solvent effects must be considered when predicting its F affinity. To further illustrate the last point, we also perform computational studies on a geometrically constrained boron ester that exhibits much stronger gas-phase affinity for both F and organic solvent molecules. After accounting for specific solvent effects, however, its net F affinity is about the same as the simple oxalate-based anion receptor. Lastly, we propose that LiF dissolution in cyclic carbonate organic solvents, in the absence of anion receptors, is due mostly to the formation of ionic aggregates, not isolated F ions.

  6. Environmental studies conducted at the Fenton Hill Hot Dry Rock geothermal development site

    SciTech Connect

    Miera, F.R. Jr.; Langhorst, G.; McEllin, S.; Montoya, C.

    1984-05-01

    An environmental investigation of Hot Dry Rock (HDR) geothermal development was conducted at Fenton Hill, New Mexico, during 1976-1979. Activities at the Fenton Hill Site included an evaluation of baseline data for biotic and abiotic ecosystem components. Identification of contaminants produced by HDR processes that had the potential for reaching the surrounding environment is also discussed. Three dominant vegetative communities were identified in the vicinity of the site. These included grass-forb, aspen, and mixed conifer communities. The grass-forb area was identified as having the highest number of species encountered, with Phleum pratense and Dactylis glomerata being the dominant grass species. Frequency of occurrence and mean coverage values are also given for other species in the three main vegetative complexes. Live trapping of small mammals was conducted to determine species composition, densities, population, and diversity estimates for this component of the ecosystem. The data indicate that Peromyscus maniculatus was the dominant species across all trapping sites during the study. Comparisons of relative density of small mammals among the various trapping sites show the grass-forb vegetative community to have had the highest overall density. Comparisons of small mammal diversity for the three main vegetative complexes indicate that the aspen habitat had the highest diversity and the grass-forb habitat had the lowest. Analyses of waste waters from the closed circulation loop indicate that several trace contaminants (e.g., arsenic, cadmium, fluoride, boron, and lithium) were present at concentrations greater than those reported for surface waters of the region.

  7. Study of the dependence the thermal conductivity of nanofluids on different parameters

    NASA Astrophysics Data System (ADS)

    Pryazhnikov, M. I.; Minakov, A. V.; Guzei, D. V.; Rudyak, V. Ya

    2016-10-01

    The paper presents the results of systematic measurements of the thermal conductivity coefficient of nanofluids at room temperature. It is shown that the thermal conductivity of all considered nanofluids depend on concentration, nanopartical size, as well as the base fluid properties. It was revealed that thermal conductivity coefficient of nanofluids increases with increasing concentration and size of nanoparticles.

  8. Change over Time: Conducting Longitudinal Studies of Children’s Cognitive Development

    PubMed Central

    Grammer, Jennie K.; Coffman, Jennifer L.; Ornstein, Peter A.; Morrison, Frederick J.

    2014-01-01

    Developmental scientists have argued that the implementation of longitudinal methods is necessary for obtaining an accurate picture of the nature and sources of developmental change (Magnusson & Cairns, 1996; Morrison & Ornstein, 1996; Magnusson & Stattin, 2006). Developmentalists studying cognition have been relatively slow to embrace longitudinal research, and thus few exemplar studies have tracked individual children’s cognitive performance over time and even fewer have examined contexts that are associated with this growth. In this article we first outline some of the benefits of implementing longitudinal designs. Using illustrations from existing studies of children’s basic cognitive development and of their school-based academic performance, we discuss when it may be appropriate to employ longitudinal (versus other) methods. We then outline methods for integrating longitudinal data into one’s research portfolio, contrasting the leveraging of existing longitudinal data sets with the launching of new longitudinal studies in order to address specific questions concerning cognitive development. Finally, for those who are interested in conducting longitudinal investigations of their own, we provide practical on-the-ground guidelines for designing and carrying out such studies of cognitive development. PMID:24955035

  9. An overview of German cockroach, Blattella germanica, studies conducted in Iran.

    PubMed

    Nasirian, Hassan

    2010-11-15

    The control and elimination of German cockroach, the most important worldwide pest species, has been an economic and public health success. Too many studies have been conducted in Iran, whereas these researches was scattered in form of national and international articles that has needed to add up of them in an overview article. With doing of this work the way is smooth to future studies and the strategies of these studies will be distinguished. This article is outlook in direction of above aims. The susceptibility level and insecticide resistance mechanisms of German cockroach to organochlorated, organophosphate, carbamate and pyrethroid insecticide groups have been studied. The new insecticidal compounds include fipronil and avermectins acting at GABA and glutamate receptors in proximity to chloride channels, diacylhydrazines mimicking the action of ecdysone, indoxacarb acting at a novel site in sodium channels and imidacloprid, thiamethoxam and spinosad acting at novel sites on the nicotinic acetylcholine receptor, several promising products acting at new target sites, which are currently not affected by resistance that will be used for pest control specially Blattella germanica. Attentive to resistance of B. germanica to current consuming insecticides and ever-increasing add to intensity of it, the researchers have been considering the susceptibility level of B. germanica and efficiency estimation of them to above-mentioned insecticides for control of this pest. The strategies of future researches are study of the susceptibility level of B. germanica and efficiency estimation of them to above-mentioned insecticides for control of this pest in Iran.

  10. Upper limb movements and outcome in intrauterine-growth-retarded infants at 2 years.

    PubMed

    Zuk, Luba; Harel, Shaul; Leitner, Yael; Jaffa, Ariel; Fattal-Valevski, Aviva

    2008-11-01

    This study aims to examine the usefulness of spontaneous upper limb movements (ULM) as an early marker for predicting neurodevelopmental outcome in infants with intrauterine-growth retardation (IUGR). The assessment of general movements (GMs) during the first 20 weeks is an accepted method for early detection of brain dysfunction. During this period, spontaneous upper limb movements were examined in 32 infants with IUGR and 32 appropriate-for-gestational-age-matched controls. ULM (arms, forearms and hands) were scored as optimal or suboptimal by sequential videotape recordings in the writhing (term-2 weeks: score 0-5); early fidgety (9-11 weeks: score 0-6); and late fidgety (14-16 weeks: score 0-6) periods, and correlated with neurodevelopmental score at 2 years of age. The mean ULM score was lower in the IUGR infants than the controls (p<0.05) and in the IUGR group was lower in the infants with abnormal outcome (p<0.05). Significant correlations were found between ULM and 2-year neurodevelopmental scores in the IUGR group. The ULM during late-fidgety period was most predictive for 2-year neurodevelopmental score. No difference was found in the mean ULM score between the pre-term and term IUGR infants. We conclude that ULM score can serve as an early predictor for neurodevelopmental outcome at 2 years of age in infants with IUGR.

  11. Coordination of Lip Muscle Activity by 2-Year-Old Children During Speech and Nonspeech Tasks

    PubMed Central

    Ruark, Jacki L.; Moore, Christopher A.

    2014-01-01

    This investigation was designed to quantify the coordinative organization of lip muscle activity of 2-year-old children during speech and nonspeech behaviors. Electromyographic (EMG) recordings of right upper and lower lip activity of seven 2-year-old children were obtained during productions of chewing, syllable repetition, lip protrusion, and speech (repeated two-word utterances) tasks. Task comparisons revealed that the coordinative organization of upper and lower lip activity is task specific; different coordinative strategies are employed for different tasks. Lip protrusion and syllable repetition tasks yielded strong coupling of upper and lower lip activity. Lip rounding (sentences containing the lip-rounding vowel /u/) and “nonlabial” speech tasks (sentences free of bilabials and lip-rounding vowels) resulted in low coupling of upper and lower lip activity. Moderate levels of coupling of upper and lower lip activity were evident for chewing and bilabial speech tasks (sentences loaded with bilabial plosion). This finding, that the coordinative elements of the perioral system of 2-year-olds are task specific, extends the results of previous studies of adults and children, where task-specific coordinative strategies were employed by the mandibular and perioral systems (Moore, 1993; Moore & Ruark, 1996; Moore, Smith, & Ringel, 1988; Wohlert & Goffman, 1994). The task-dependent coordination of the perioral system of 2-year-olds supports the notion that developing speech and earlier developing oromotor behaviors (i.e., sucking, chewing) are mediated by different control mechanisms. PMID:9430757

  12. Pseudogap studied by optical conductivity spectra of Zn-substituted YBa2Cu3Oy

    NASA Astrophysics Data System (ADS)

    Uykur, Ece; Masui, Takahiko; Tanaka, Kiyohisa; Miyasaka, Shigeki; Tajima, Setsuko

    2012-02-01

    The pseudogap and the superconducting gap cause a similar suppression of the low energy optical conductivity, but the behaviors of the spectral weight transfers are different, which enables us to distinguish these two gaps. In the c-axis spectra of YBa2Cu3Oy, however, it is difficult to discuss these spectral weight transfers because of the additional structures due to a transverse Josephson plasma mode [1]. To overcome this problem, we substituted Zn for Cu, which is known to suppress those supplementary structures [2]. In this study, we performed temperature dependent reflectivity measurements in Zn-substituted YBa2Cu3Oy system. We have revealed the continuous transfer of the low energy spectral weight to the higher energy region even below Tc, which suggests the coexistence of the pseudogap and the superconducting gap. [1]C. Bernhard et al. Phys. Rev. B, 61 (2000) 618. [2]R. Hauff et al., Phys. Rev. Lett., 77 (1996) 4620.

  13. Synthesis, characterization and conductivity studies of ZnFe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Narsimulu, D.; Venkateswarlu, M.; Satyanarayana, N.

    2015-06-01

    Transition metal ferrites with general formula AB2O4 (A=Co, Cu, Mn, Zn, B=Fe+3) could be used as an anode materials in lithium ion battery (LIB), because, lithium ion batteries fabricated using ferrite materials show the high capacity than commonly used graphite. The ZnFe2O4 with cubic spinel structured material was prepared by acrylamide assisted citrate combustion process. Phase, structural coordination and thermal behavior of the prepared ZnFe2O4 were confirmed by powder X-ray diffraction, FTIR spectra and TG/DTA thermogram respectively. Morphology and specific surface area of the ZnFe2O4 were identified by SEM and BET surface analyzer respectively and its conductivity studies were made through impedance spectroscopy.

  14. Synthesis, characterization and conductivity studies of ZnFe{sub 2}O{sub 4} nanoparticles

    SciTech Connect

    Narsimulu, D.; Satyanarayana, N.; Venkateswarlu, M.

    2015-06-24

    Transition metal ferrites with general formula AB{sub 2}O{sub 4} (A=Co, Cu, Mn, Zn, B=Fe{sup +3}) could be used as an anode materials in lithium ion battery (LIB), because, lithium ion batteries fabricated using ferrite materials show the high capacity than commonly used graphite. The ZnFe{sub 2}O{sub 4} with cubic spinel structured material was prepared by acrylamide assisted citrate combustion process. Phase, structural coordination and thermal behavior of the prepared ZnFe{sub 2}O{sub 4} were confirmed by powder X-ray diffraction, FTIR spectra and TG/DTA thermogram respectively. Morphology and specific surface area of the ZnFe{sub 2}O{sub 4} were identified by SEM and BET surface analyzer respectively and its conductivity studies were made through impedance spectroscopy.

  15. Computational studies of solid-state alkali conduction in rechargeable alkali-ion batteries

    SciTech Connect

    Deng, Zhi; Mo, Yifei; Ong, Shyue Ping

    2016-03-25

    The facile conduction of alkali ions in a crystal host is of crucial importance in rechargeable alkali-ion batteries, the dominant form of energy storage today. In this review, we provide a comprehensive survey of computational approaches to study solid-state alkali diffusion. We demonstrate how these methods have provided useful insights into the design of materials that form the main components of a rechargeable alkali-ion battery, namely the electrodes, superionic conductor solid electrolytes and interfaces. We will also provide a perspective on future challenges and directions. Here, the scope of this review includes the monovalent lithium- and sodium-ion chemistries that are currently of the most commercial interest.

  16. Computational studies of solid-state alkali conduction in rechargeable alkali-ion batteries

    DOE PAGES

    Deng, Zhi; Mo, Yifei; Ong, Shyue Ping

    2016-03-25

    The facile conduction of alkali ions in a crystal host is of crucial importance in rechargeable alkali-ion batteries, the dominant form of energy storage today. In this review, we provide a comprehensive survey of computational approaches to study solid-state alkali diffusion. We demonstrate how these methods have provided useful insights into the design of materials that form the main components of a rechargeable alkali-ion battery, namely the electrodes, superionic conductor solid electrolytes and interfaces. We will also provide a perspective on future challenges and directions. Here, the scope of this review includes the monovalent lithium- and sodium-ion chemistries that aremore » currently of the most commercial interest.« less

  17. New geoscience teachers division for 2-year colleges

    NASA Astrophysics Data System (ADS)

    Krumm, Debra; Granshaw, Frank

    2011-11-01

    The role of 2-year colleges (2YCs) in geoscience education is growing as the number of students enrolled in Earth and space science courses increases and as these institutions—which include community colleges and junior colleges—provide more students majoring in geoscience at public universities. In recognition of the increasing role of 2YCs in geoscience education, the National Association of Geoscience Teachers (NAGT) recently created a Geo2YC division for faculty, administrators, graduate students, and other geoscience professionals who share a professional interest in geoscience education at 2YCs. The mission of the new division, which is NAGT's first national division, is to serve as a forum for exchanging curricular ideas, concerns, and resources; establish a network of geoscience educators at 2YCs and other institutions with shared interests; sponsor NAGT 2YC activities and make recommendations to the NAGT Council in support of 2YC geoscience education; support and coordinate research on 2YC geoscience education; and advocate for 2YC geoscience education within NAGT and with other organizations.

  18. Tacrolimus ointment: utilization patterns in children under age 2 years.

    PubMed

    Housman, Tamara Salam; Norton, Amy B; Feldman, Steven R; Fleischer, Alan B; Simpson, Eric L; Hanifin, Jon M; Antaya, Richard J

    2004-07-15

    Atopic dermatitis (AD) is a common eczematous skin condition; as many as 10-17 percent of all children are affected, and 35-60 percent of affected patients manifest symptoms manifest during the first year of life. Treatment principles for AD in young children involve conservative measures such as avoidance of hot water and environmental irritants, combined with liberal use of emollients after bathing. Low potency topical corticosteroids (TCS) are the current standard of therapy for AD in young children, reserving mid- and high-potency TCS for severe disease. However, complications of long-term use of TCS include skin atrophy, stria formation, telangiectasia, hypopigmentation, secondary infections, steroid acne, allergic contact dermatitis, and miliaria. The pediatric population is also at increased risk for systemic absorption because of their high ratio of skin surface to body mass. Systemic absorption may result in hypothalamic-pituitary-adrenal axis suppression and ultimately growth retardation. Although most topical and systemic corticosteroids are not approved by the Food and Drug Administration for use in children less than 2 years of age, conservative treatment often fails in this age group and frequently patients are treated with TCS, antibiotics, and antihistamines.

  19. Conductivity studies of LiCF3SO3 doped PVA: PVdF blend polymer electrolyte

    NASA Astrophysics Data System (ADS)

    Tamilselvi, P.; Hema, M.

    2014-03-01

    Different composition of lithium ion conducting PVA: PVdF: Lithium triflate (LiCF3SO3) polymer electrolytes have been prepared by solution casting technique. Dielectric and conductivity studies have been carried out for the prepared samples. The addition of salt into the polymer matrix increases the ionic conductivity of blend polymer electrolytes. The conductivity analysis reveals 80PVA: 20PVdF: 15LiCF3SO3 polymer electrolyte exhibits the maximum ionic conductivity of 2.7×10-3 S cm-1 at 303 K. The temperature dependence of ionic conductivity for all the composition of PVA: PVdF: LiCF3SO3 polymer films obey Arrhenius relation. Low activation energy has been obtained for highest conducting sample. The dielectric spectra show absolute β-relaxation peak.

  20. Thermal boundary conductance enhancement using experimentally achievable nanostructured interfaces - analytical study combined with molecular dynamics simulation.

    PubMed

    Lee, Eungkyu; Zhang, Teng; Hu, Ming; Luo, Tengfei

    2016-06-22

    Interfacial thermal resistance presents great challenges to the thermal management of modern electronics. In this work, we perform an analytical study to enhance the thermal boundary conductance (TBC) of nanostructured interfaces with square-shape pillar arrays, extendable to the characteristic lengths that can be fabricated in practice. As a representative system, we investigate a SiC substrate with the square-shape pillar array combined with epitaxial GaN as the nanostructured interface. By applying a first-order ray tracing method and molecular dynamics simulations to analyze phonon incidence and transmission at the nanostructured interface, we systematically study the impact of the characteristic dimensions of the pillar array on the TBC. Based on the multi-scale analysis we provide a general guideline to optimize the nanostructured interfaces to achieve higher TBC, demonstrating that the optimized TBC value of the nanostructured SiC/GaN interfaces can be 42% higher than that of the planar SiC/GaN interfaces without nanostructures. The model used and results obtained in this study will guide the further experimental realization of nanostructured interfaces for better thermal management in microelectronics.

  1. The REporting of studies Conducted using Observational Routinely-collected health Data (RECORD) Statement

    PubMed Central

    Benchimol, Eric I.; Smeeth, Liam; Guttmann, Astrid; Harron, Katie; Moher, David; Petersen, Irene; Sørensen, Henrik T.; von Elm, Erik; Langan, Sinéad M.

    2015-01-01

    Routinely collected health data, obtained for administrative and clinical purposes without specific a priori research goals, are increasingly used for research. The rapid evolution and availability of these data have revealed issues not addressed by existing reporting guidelines, such as Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). The REporting of studies Conducted using Observational Routinely collected health Data (RECORD) statement was created to fill these gaps. RECORD was created as an extension to the STROBE statement to address reporting items specific to observational studies using routinely collected health data. RECORD consists of a checklist of 13 items related to the title, abstract, introduction, methods, results, and discussion section of articles, and other information required for inclusion in such research reports. This document contains the checklist and explanatory and elaboration information to enhance the use of the checklist. Examples of good reporting for each RECORD checklist item are also included herein. This document, as well as the accompanying website and message board (http://www.record-statement.org), will enhance the implementation and understanding of RECORD. Through implementation of RECORD, authors, journals editors, and peer reviewers can encourage transparency of research reporting. PMID:26440803

  2. [The REporting of studies Conducted using Observational Routinely-collected health Data (RECORD) statement].

    PubMed

    Benchimol, Eric I; Smeeth, Liam; Guttmann, Astrid; Harron, Katie; Hemkens, Lars G; Moher, David; Petersen, Irene; Sørensen, Henrik T; von Elm, Erik; Langan, Sinéad M

    2016-10-01

    Routinely collected health data, obtained for administrative and clinical purposes without specific a priori research goals, are increasingly used for research. The rapid evolution and availability of these data have revealed issues not addressed by existing reporting guidelines, such as Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). The REporting of studies Conducted using Observational Routinely collected health Data (RECORD) statement was created to fill these gaps. RECORD was created as an extension to the STROBE statement to address reporting items specific to observational studies using routinely collected health data. RECORD consists of a checklist of 13 items related to the title, abstract, introduction, methods, results, and discussion section of articles, and other information required for inclusion in such research reports. This document contains the checklist as well as explanatory and elaboration information to enhance the use of the checklist. Examples of good reporting for each RECORD checklist item are also included. This document, as well as the accompanying website and message board (http://www.record-statement.org), will improve the implementation and understanding of RECORD. By implementing RECORD, authors, journals editors, and peer reviewers can enhance transparency of research reporting.

  3. Experimental and numerical study of the effective thermal conductivity of silica nanocomposites with thermal boundary resistance

    SciTech Connect

    Kothari, Rushabh M; Dinwiddie, Ralph Barton; Wang, Hsin

    2013-01-01

    . The current study presents experimental study of thermal boundary resistance for silica nano particles embedded inside epoxy resin. The bulk conductivity of the sample is measured and Rc is back calculated using Hasselman-Johnson s (H-J) equation. The numerical validation of the equation is also presented, including extrapolation study to predict effective conductivity of the nanocomposite TIM.

  4. Study of thermally reworkable epoxy materials and thermal conductivity enhancement using carbon fiber for electronics packaging

    NASA Astrophysics Data System (ADS)

    Li, Haiying

    Epoxy resins are widely used as the underfill materials for the integrated circuit (IC) chips for the reliability enhancement and as the binder of electrically conductive adhesives (ECA). However, cured epoxy materials are infusible and insoluble networks which is a problem for the repair of a printed circuit board assembly packaged with epoxy materials. In this study, six diepoxides containing aromatic moieties and low temperature degradable linkages, secondary and tertiary benzoates, and carbonates, were synthesized and characterized. Underfills based on four of these epoxides were developed and evaluated respect to their properties and reworkabilility. One of the reworkable underfills was evaluated with the 85°C/85% relative humidity test as the underfill of several ball-grid-array components on a organic board, which showed a high enhanced reliability. Underfill materials based on a synthesized bisphenol-A diepoxide were developed for the no-flow underfill process and were evaluated regarding the application on both tin/lead and lead-free solders. The latent curing mechanism of the catalyst and the influence of fluxing agents were studied. The reworkable underfills showed satisfying overall properties on both Sn/Pb and Sn/Ag/Cu solders. A unique approach for solving the problem of low reliability of ECAs was demonstrated. Small amount of sacrificial metal and alloy powders were added in silver flake based ECA and applied on six pad surfaces. The aging of bulk resistivity and contact resistance of ECA/metal surface pairs were studied and two alloys stabilized the contact resistance on all tested metal surfaces. The internal heat generation of IC devices quickly increases which leads to deteriorated performance and low reliability. The thermally insulating property of polymeric underfills make this even worse with slow heat dissipation. In this study, a carbon fiber of high thermal conductivity was used together with silica in epoxy underfill materials and a 300

  5. Thermal conductivity and localization in glasses: Numerical study of a model of amorphous silicon

    NASA Astrophysics Data System (ADS)

    Feldman, Joseph L.; Kluge, Mark D.; Allen, Philip B.; Wooten, Frederick

    1993-11-01

    Numerical calculations of thermal conductivity κ(T) are reported for realistic atomic structure models of amorphous silicon with 1000 atoms and periodic boundary conditions. Using Stillinger-Weber forces, the vibrational eigenstates are computed by exact diagonalization in harmonic approximation. Only the uppermost 3% of the states are localized. The finite size of the system prevents accurate information about low-energy vibrations, but the 98% of the modes with energies above 10 meV are densely enough represented to permit a lot of information to be extracted. Each harmonic mode has an intrinsic (harmonic) diffusivity defined by the Kubo formula, which we can accurately calculate for ω>10 meV. If the mode could be assigned a wave vector k and a velocity v=∂ω/∂k, then Boltzmann theory assigns a diffusivity Dk=1/3vl, where l is the mean free path. We find that we cannot define a wave vector for the majority of the states, but the intrinsic harmonic diffusivity is still well-defined and has a numerical value similar to what one gets by using the Boltzmann result, replacing v by a sound velocity and replacing l by an interatomic distance a. This appears to justify the notion of a minimum thermal conductivity as discussed by Kittel, Slack, and others. In order to fit the experimental κ(T) it is necessary to add a Debye-like continuation from 10 meV down to 0 meV. The harmonic diffusivity becomes a Rayleigh ω-4 law and gives a divergent κ(T) as T-->0. To eliminate this we make the standard assumption of resonant-plus-relaxational absorption from two-level systems (this is an anharmonic effect which would lie outside our model even if it did contain two-level systems implicitly). A reasonable fit and explanation then results for the behavior of κ(T) in all temperature regimes. We also study the effect of increasing the harmonic disorder by substitutional mass defects (modeling amorphous Si/Ge alloys). The additional disorder increases the fraction of

  6. A study of the conductive properties of nanostructured metal oxide films

    NASA Astrophysics Data System (ADS)

    D'Olembert, Andre A.

    Fuel cells which were first employed in spacecraft, producing both electricity and water for astronaut consumption during the mid-1960's, are part of the ongoing pursuit for renewable energy sources, and environmentally compatible electric power generation. Recent enhancements in design and materials might establish fuel cells in a sustainable hydrogen energy economy (SHEE) as viable alternatives to the internal combustion engine. In tune with our principal objectives, this study investigates the conductive properties of metal-oxide thin films by developing a new deposition technique called dual channel ultrasonic spray pyrolysis (DC-USP). The DC-USP process has proved to be a reliable and cost-effective method to fabricate thin films. Extending the DC-USP technique, we have created a novel mixed ionic electronic conductor (MIEC) composed of two metal-oxides: lanthanum strontium ferrite and copper-doped bismuth vanadate (LSF.40:BiCuVOx.10). When the two materials are mixed, their grain boundary regions are heavily defected because of the dissimilarity of the two crystal structures, which maintain their integrity in the formed heterogenous composite. Oxygen ion diffusion occurs as it migrates through an ionic crystal, hopping from defect site to defect site. Furthermore, a nanostructured material - with crystallite grains less than 100 nm in diameter - will improve oxygen diffusion by increasing the density of defect sites. The rate of diffusion is increased as well as the quantity of diffusion pathways. Ultimately, as the ionic current density is increased, the total efficiency (nuSOFCtotal) of the solid oxide fuel cell (SOFC) can be improved. Therefore, the LSF-40:BiCuVOx.10 material can contribute to solve the major outstanding problem of the three-phase boundary (TPB) that limits the oxygen reduction reaction to within a microscopic region near the cathode-electrolyte interface in the SOFC device. Materials were tested and analyzed using atomic force microscopy

  7. Glycosylated Conductive Polymer: A Multimodal Biointerface for Studying Carbohydrate-Protein Interactions.

    PubMed

    Zeng, Xiangqun; Qu, Ke; Rehman, Abdul

    2016-09-20

    Carbohydrate-protein interactions occur through glycoproteins, glycolipids, or polysaccharides displayed on the cell surface with lectins. However, studying these interactions is challenging because of the complexity and heterogeneity of the cell surface, the inherent structural complexity of carbohydrates, and the typically weak affinities of the binding reactions between the lectins and monovalent carbohydrates. The lack of chromophores and fluorophores in carbohydrate structures often drives such investigations toward fluorescence labeling techniques, which usually require tedious and complex synthetic work to conjugate fluorescent tags with additional risk of altering the reaction dynamics. Probing these interactions directly on the cell surface is even more difficult since cells could be too fragile for labeling or labile dynamics could be affected by the labeled molecules that may interfere with the cellular activities, resulting in unwanted cell responses. In contrast, label-free biosensors allow real-time monitoring of carbohydrate-protein interactions in their natural states. A prerequisite, though, for this strategy to work is to mimic the coding information on potential interactions of cell surfaces onto different biosensing platforms, while the complementary binding process can be transduced into a useful signal noninvasively. Through carbohydrate self-assembled monolayers and glycopolymer scaffolds, the multivalency of the naturally existing simple and complex carbohydrates can be mimicked and exploited with label-free readouts (e.g., optical, acoustic, mechanical, electrochemical, and electrical sensors), yet such inquiries reflect only limited aspects of complicated biointeraction processes due to the unimodal transduction. In this Account, we illustrate that functionalized glycosylated conductive polymer scaffolds are the ideal multimodal biointerfaces that not only simplify the immobilization process for surface fabrication via electrochemical

  8. Thermal conductivity of sawtooth-like graphene nanoribbons: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Zhang, Hui-Sheng; Guo, Zhi-Xin; Gong, Xin-Gao; Cao, Jue-Xian

    2012-12-01

    In this work, we have employed the classical non-equilibrium molecular dynamics method to investigate the thermal conductivity of sawtooth-like graphene nanoribbons (SGNRs). It is found that the thermal conductivity of SGNRs is much smaller than that of straight armchair-GNRs. When the length of SGNRs is fixed, the thermal conductivity of SGNRs is very sensitive to n (length of the segmented graphene nanoribbons (GNRs)). Our results indicate that the thermal conductivity of SGNRs reduces remarkably at first and then increases with n increasing. The length and width dependence of thermal conductivity for SGNRs is further explored. Interestingly, we find the thermal conductivity of SGNRs is nearly independent on the length, while it is more sensitive to the width. Our results provide a better understanding for GNR and GNR based nanostructures in thermal management.

  9. Mapping longitudinal development of local cortical gyrification in infants from birth to 2 years of age.

    PubMed

    Li, Gang; Wang, Li; Shi, Feng; Lyall, Amanda E; Lin, Weili; Gilmore, John H; Shen, Dinggang

    2014-03-19

    Human cortical folding is believed to correlate with cognitive functions. This likely correlation may have something to do with why abnormalities of cortical folding have been found in many neurodevelopmental disorders. However, little is known about how cortical gyrification, the cortical folding process, develops in the first 2 years of life, a period of dynamic and regionally heterogeneous cortex growth. In this article, we show how we developed a novel infant-specific method for mapping longitudinal development of local cortical gyrification in infants. By using this method, via 219 longitudinal 3T magnetic resonance imaging scans from 73 healthy infants, we systemically and quantitatively characterized for the first time the longitudinal cortical global gyrification index (GI) and local GI (LGI) development in the first 2 years of life. We found that the cortical GI had age-related and marked development, with 16.1% increase in the first year and 6.6% increase in the second year. We also found marked and regionally heterogeneous cortical LGI development in the first 2 years of life, with the high-growth regions located in the association cortex, whereas the low-growth regions located in sensorimotor, auditory, and visual cortices. Meanwhile, we also showed that LGI growth in most cortical regions was positively correlated with the brain volume growth, which is particularly significant in the prefrontal cortex in the first year. In addition, we observed gender differences in both cortical GIs and LGIs in the first 2 years, with the males having larger GIs than females at 2 years of age. This study provides valuable information on normal cortical folding development in infancy and early childhood.

  10. Cytokines as a predictor of clinical response following hip arthroscopy: minimum 2-year follow-up

    PubMed Central

    Shapiro, Lauren M.; Safran, Marc R.; Maloney, William J.; Goodman, Stuart B.; Huddleston, James I.; Bellino, Michael J.; Scuderi, Gaetano J.; Abrams, Geoffrey D.

    2016-01-01

    Hip arthroscopy in patients with osteoarthritis has been shown to have suboptimal outcomes. Elevated cytokine concentrations in hip synovial fluid have previously been shown to be associated with cartilage pathology. The purpose of this study was to determine whether a relationship exists between hip synovial fluid cytokine concentration and clinical outcomes at a minimum of 2 years following hip arthroscopy. Seventeen patients without radiographic evidence of osteoarthritis had synovial fluid aspirated at time of portal establishment during hip arthroscopy. Analytes included fibronectin–aggrecan complex as well as a multiplex cytokine array. Patients completed the modified Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index and the International Hip Outcomes Tool pre-operatively and at a minimum of 2 years following surgery. Pre and post-operative scores were compared with a paired t-test, and the association between cytokine values and clinical outcome scores was performed with Pearson’s correlation coefficient with an alpha value of 0.05 set as significant. Sixteen of seventeen patients completed 2-year follow-up questionnaires (94%). There was a significant increase in pre-operative to post-operative score for each clinical outcome measure. No statistically significant correlation was seen between any of the intra-operative cytokine values and either the 2-year follow-up scores or the change from pre-operative to final follow-up outcome values. No statistically significant associations were seen between hip synovial fluid cytokine concentrations and 2-year follow-up clinical outcome assessment scores for those undergoing hip arthroscopy. PMID:27583163

  11. Severe bronchiolitis in infants born very preterm and neurodevelopmental outcome at 2 years.

    PubMed

    Gouin, Marion; Nguyen, Sylvie; Savagner, Christophe; Troussier, Francoise; Gascouin, Géraldine; Rozé, Jean-Christophe; Flamant, Cyril

    2013-05-01

    Preterm infants are at greater risk of bronchopulmonary dysplasia, which is associated with neurodevelopmental impairment. These infants are also more likely to develop severe bronchiolitis, which can contribute to neurodevelopmental impairment. The aim of this study was to determine whether severe bronchiolitis in very preterm infants (born before 33 weeks of gestation) was associated with an increased risk of neurodevelopmental impairment at 2 years of age. We analyzed a population-based cohort of infants (the Loire Infant Follow-up Team cohort) born between 1 January 2003 and 31 December 2009. Severe bronchiolitis was defined as hospitalization due to bronchiolitis during the first year of life. Neurodevelopmental outcome was assessed at 2 years of corrected age. A total of 2,405 infants were included in this analysis and categorized based on neonatal respiratory status: 1,308 (54.4 %) received no respiratory assistance, 864(35.9 %) received oxygen for <28 days, and 167 (6.9 %) had mild and 66 (2.7) moderate or severe bronchopulmonary dysplasia. At 2 years, 502 children displayed non-optimal neurodevelopmental outcome (20.9 %). Moderate or severe bronchopulmonary dysplasia was significantly associated with non-optimal neurodevelopmental outcome at 2 years (adjusted odds ratios (OR) = 2.3 [95 % confidence interval (CI): 1.3-3.9], p = 0.003). In the first year, 318 infants acquired severe bronchiolitis (13.2 %), which was not associated with non-optimal neurodevelopmental outcome (adjusted OR = 1.0 [95 % CI: 0.8-1.4]; p = 0.88). In conclusion, respiratory status in the neonatal period was significantly associated with non-optimal neurodevelopmental outcome at 2 years, while severe bronchiolitis was not.

  12. Risk factors for cardiovascular disease during the first 2 years after renal transplantation.

    PubMed

    Laurés, A S; Gómez, E; Baltar, J; Alvarez-Grande, J

    2005-11-01

    The aim of the present study was to assess the role of cardiovascular risk factors in the occurrence of cardiovascular events among 100 consecutive renal transplant recipients during the first 2 years after transplantation. The following parameters were analyzed: (1) demographic data (gender, age, dialysis duration, preexistent diabetes, and pretransplantation events) as well as (2) basal 1-year, and 2-year posttransplantation data for events, body mass index, arterial hypertension, number of drugs for hypertension control, use of ACE or ARA II inhibitors, treatment with lipid- lowering drugs, de novo diabetes, anemia, immunosuppression with cyclosporine versus tacrolimus, and homocysteine, folic acid, serum creatinine, uric acid, PTH-i, and cholesterol total, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, and triglyceride levels. At the end of the second posttransplantation year, 14 patients versus 86 who did not experience a new cardiovascular event. Patients in the event group had more events pretransplantation and during the first posttransplantation year than those in the non event group (57.1% vs 17.4%; P = .003 and 78.6% vs 2.3%; P = .000, respectively). Furthermore, the former cohort of patients were older, had greater ventricular hypertrophy and had higher triglyceride and serum creatinine concentrations during the 2 years after transplantation. A multiple logistic regression analysis confirmed the relationship between events within 1 year of transplantation and serum creatinine level at the end of 2 years as well as the development of cardiovascular disease within 2 years. In conclusion, our data suggest the need for aggressive intervention during the first year to prevent the development of new cardiovascular events. Renoprotective strategies may also contribute to reduce the cardiovascular risk of renal transplant recipients.

  13. RSV frequency in children below 2 years hospitalized for lower respiratory tract infections.

    PubMed

    Hacımustafaoğlu, Mustafa; Celebi, Solmaz; Bozdemir, Sefika Elmas; Ozgür, Taner; Ozcan, Ismail; Güray, Atilla; Cakır, Deniz

    2013-01-01

    Respiratory syncytial virus (RSV) is the most frequent agent of acute lower respiratory diseases and creates a significant burden of disease in children under 5 years all over the world. RSV causes severe lower respiratory tract infections (LRTI) that require hospitalization, especially in children ≤2 years. The aim of this study was to determine the incidence of RSV in children ≤2 years of age hospitalized for LRTI. Children ≤2 years of age hospitalized for one year for LRTI in the three largest hospitals of Bursa City Center, Turkey were evaluated. These three hospitals comprise 67.5% of all child beds in central Bursa, so this study allows us to evaluate the total disease burden and hospitalization incidence in central Bursa. Nasal swabs of the children were evaluated with RSV Respi- Strip (Coris Bioconcept Organization). A total of 671 children were hospitalized for LRTI, and 254 (37.9%) had at least one hospitalization that was positive for RSV. Of all patients with LRTI, 54.8% (368/671) were hospitalized for acute bronchiolitis, while 45.2% (303/671) were hospitalized for pneumonia. Of patients with acute bronchiolitis or pneumonia, 41% (151/368) and 34% (103/303) were RSV+, respectively. Of RSV+ hospitalized children, 59.5% (151/254) were diagnosed as acute bronchiolitis and 40.5% (103/254) as pneumonia. The annual incidences of hospitalization due to LRTI, acute bronchiolitis and pneumonia were 20.5/1000, 11.2/1000 and 9.3/1000, respectively, in children ≤2 years of age. The annual incidences of hospitalization due to RSV+ LRTI, acute bronchiolitis and pneumonia were found as 7.8/1000, 4.6/1000 and 3.2/1000, respectively, in children ≤2 years of age. More than one-third of all children hospitalized with LRTI (38.3%, n=257) were in the 0-3 months age group. Compared to other age groups, RSV positivity was highest in that age group for acute bronchiolitis (57%), pneumonia (39.5%) and also total children with LRTI (47.9%). RSV is a very important

  14. Inhibitor studies of leaf lamina hydraulic conductance in trembling aspen (Populus tremuloides Michx.) leaves.

    PubMed

    Voicu, Mihaela C; Zwiazek, Janusz J

    2010-02-01

    The present study investigated leaf water transport properties in trembling aspen (Populus tremuloides) leaves. Leaf lamina hydraulic conductance (K(lam)) and stomatal conductance (g(s)) were drastically suppressed by NaF (a general metabolic inhibitor). In leaves treated with 0.2 mM HgCl(2) (an aquaporin blocker), K(lam) declined by 22% when the leaves were sampled in June but the decline was not significant when the leaves were sampled in August. The leaves sampled in June that transpired 30 mM beta-mercaptoethanol following mercury application showed similar K(lam) as those in control leaves transpiring distilled water. When leaves were pressure-infiltrated with 0.1 mM HgCl(2), K(lam) significantly declined by 25%. Atrazine (a photosystem II inhibitor) drastically reduced leaf net CO(2) uptake by the leaves from seedlings and mature trees but did not have any effect on K(lam) regardless of the irradiance at the leaf level during the K(lam) measurements. When PTS(3) (trisodium 3-hydroxy-5,8,10-pyrenetrisulphonate) apoplastic tracer was pressure-infiltrated inside the leaves, its concentration in the leaf exudates did not change from ambient light to high irradiance treatment and declined in the presence of HgCl(2) in the treatment solution. Trembling aspen K(lam) appears to be linked to leaf metabolism and is uncoupled from the short-term variations in photosynthesis. Aquaporin-mediated water transport does not appear to constitute the dominant pathway for the pressure-driven water flow in the leaves of trembling aspen trees.

  15. An Experimental Study of the Effects of A Rotating Magnetic Field on Electrically Conducting Aqueous Solutions

    NASA Technical Reports Server (NTRS)

    Ramachandran Narayanan; Mazuruk, Konstantin

    1998-01-01

    The use of a rotating magnetic field for stirring metallic melts has been a commonly adopted practice for a fairly long period. The elegance of the technique stems from its non-intrusive nature and the intense stirring it can produce in an electrically conducting medium. A further application of the method in recent times has been in the area of crystal growth from melts (e.g. germanium). The latter experiments have been mainly research oriented in order to understand the basic physics of the process and to establish norms for optimizing such a technique for the commercial production of crystals. When adapted for crystal growth applications, the rotating magnetic field is used to induce a slow flow or rotation in the melt which in effect significantly curtails temperature field oscillations in the melt. These oscillations are known to cause dopant striations and thereby inhomogeneities in the grown crystal that essentially degrades the crystal quality. The applied field strength is typically of the order of milli-Teslas with a frequency range between 50-400 Hz. In this investigation, we report findings from experiments that explore the feasibility of applying a rotating magnetic field to aqueous salt solutions, that are characterized by conductivities that are several orders of magnitude smaller than semi-conductor melts. The aim is to study the induced magnetic field and consequently the induced flow in such in application. Detailed flow field description obtained through non-intrusive particle displacement tracking will be reported along with an analytical assessment of the results. It is anticipated that the obtained results will facilitate in establishing a parameter range over which the technique can be applied to obtain a desired flow field distribution. This method can find applicability in the growth of crystals from aqueous solutions and give an experimenter another controllable parameter towards improving the quality of the grown crystal.

  16. An experimental study of perovskite-structured mixed ionic- electronic conducting oxides and membranes

    NASA Astrophysics Data System (ADS)

    Zeng, Pingying

    In recent decades, ceramic membranes based on mixed ionic and electronic conducting (MIEC) perovskite-structured oxides have received many attentions for their applications for air separation, or as a membrane reactor for methane oxidation. While numerous perovskite oxide materials have been explored over the past two decades; there are hardly any materials with sufficient practical economic value and performance for large scale applications, which justifies continuing the search for new materials. The main purposes of this thesis study are: (1) develop several novel SrCoO3-delta based MIEC oxides, SrCoCo1-xMxO3-delta, based on which membranes exhibit excellent oxygen permeability; (2) investigate the significant effects of the species and concentration of the dopants M (metal ions with fixed valences) on the various properties of these membranes; (3) investigate the significant effects of sintering temperature on the microstructures and performance of oxygen permeation membranes; and (4) study the performance of oxygen permeation membranes as a membrane reactor for methane combustion. To stabilize the cubic phase structure of the SrCoO3-delta oxide, various amounts of scandium was doped into the B-site of SrCoO 3-delta to form a series of new perovskite oxides, SrScxCoCo 1-xO3-delta (SSCx, x = 0-0.7). The significant effects of scandium-doping concentration on the phase structure, electrical conductivity, sintering performance, thermal and structural stability, cathode performance, and oxygen permeation performance of the SSCx membranes, were systematically studied. Also for a more in-depth understanding, the rate determination steps for the oxygen transport process through the membranes were clarified by theoretical and experimental investigation. It was found that only a minor amount of scandium (5 mol%) doping into the B-site of SrCoO3-delta can effectively stabilize the cubic phase structure, and thus significantly improve the electrical conductivity and

  17. Sage grouse on the Yakima Training Center: A summary of studies conducted during 1989 and 1990

    SciTech Connect

    Eberhardt, L.E. ); Hofmann, L.A. . Coe-Truman Technologies)

    1991-03-01

    A two-year study, sponsored by the U.S. Department of the Army and conducted by Pacific Northwest Laboratory, was initiated in 1989 to study sage grouse on the Yakima Training Center (YTC). The specific objectives of this study were (1) to obtain detailed information on the distribution and relative density of sage grouse on the YTC, (2) to identify movement and habitat use patterns of sage grouse on the YTC, (3) to identify crucial habitat for sage grouse on the YTC, and (4) to provide management recommendations. Sage grouse were selected for study because they are a US Fish and Wildlife Service candidate species for the threatened and endangered list in Washington, and because the YTC probably contains the largest population of sage grouse left on federally owned lands in this state. The locations of 11 sage grouse leks, or breeding grounds, were determined on the YTC during extensive spring helicopter surveys. The maximum number of sage grouse observed during ground surveys of these leks varied from 2 to 55 birds. One lek, located near Range 19, was probably used by 40 to 50% of the YTC sage grouse population. Fifteen years of counts of males on leks indicate that the YTC sage grouse population was most numerous during the early to mid 1980s. Since the mid-1980s, sage grouse numbers appear to have declined on the YTC and in other locations in Washington. Forty-six sage grouse (17 females and 29 males) were captured and fitted with radio transmitters during 1989 and 1990. Movements by these sage grouse were both erratic and large when compared with other studies. We believe that many of the atypical movements were in response to military training activities. Sage grouse appeared to seek out areas on the YTC where human disturbance was low. Recommendations are made for improving the management of grouse habitat.

  18. A Roentgen-anatomic study of the relationships between conduction defects and coronary disease.

    PubMed

    Veress, G; Romoda, T; Szatmáry, L; Keltai, M; Palik, I; Gábor, G

    1979-01-01

    Intraventricular conduction defects of various types were correlated to the extent of coronary disease and to the parameters reflecting the function of the left ventricle in 125 patients who had been subjected to coronary arteriography. In the patients with conduction disturbances, coronary disease was found to be more extensive and the proportion of abnormal parameters of left ventricular function higher than in those with normal conduction. The relationship of the various conduction defects with the lesions of the individual coronary branches and with the parameters of left ventricular function are discussed in detail.

  19. A theoretical computerized study for the electrical conductivity of arterial pulsatile blood flow by an elastic tube model.

    PubMed

    Shen, Hua; Zhu, Yong; Qin, Kai-Rong

    2016-12-01

    The electrical conductivity of pulsatile blood flow in arteries is an important factor for the application of the electrical impedance measurement system in clinical settings. The electrical conductivity of pulsatile blood flow depends not only on blood-flow-induced red blood cell (RBC) orientation and deformation but also on artery wall motion. Numerous studies have investigated the conductivity of pulsatile blood based on a rigid tube model, in which the effects of wall motion on blood conductivity are not considered. In this study, integrating Ling and Atabek's local flow theory and Maxwell-Fricke theory, we develop an elastic tube model to explore the effects of wall motion as well as blood flow velocity on blood conductivity. The simulation results suggest that wall motion, rather than blood flow velocity, is the primary factor that affects the conductivity of flowing blood in arteries.

  20. The OAO heat pipes - 8 1/2 years of flight data

    NASA Technical Reports Server (NTRS)

    Harwell, W.; Mcintosh, R.

    1981-01-01

    Heat pipe performance data taken during the 8 1/2 years of flight of the OAO-C (Copernicus) spacecraft are presented. Three fixed conductance heat pipes (FCHP), each with different wicking concepts (axial groove, pedestal artery, and self-priming spiral artery), and one variable conductance heat pipe (VCHP) are onboard. Aluminum tubes (1/2 in. diameter) rolled into a 48 in. loop containing ultra high purity ammonia as the heat transfer fluid comprise all FCHP, whose purpose is to circumferentially isothermalize the central tube housing the telescope. The VCHP is a hot, non-wicked reservoir concept including a composite artery and methanol heat transfer fluid, and is used to maintain the temperature of the onboard processor. Flight thermal data analysis reveals that no degradation in performance occurred since launch and agrees well with pre-flight data; the onboard processor still shows an offset in control range of 4 F, and the pipes perform the same after 8 1/2 years in orbit.

  1. A genome-wide association study of upper aerodigestive tract cancers conducted within the INHANCE consortium.

    PubMed

    McKay, James D; Truong, Therese; Gaborieau, Valerie; Chabrier, Amelie; Chuang, Shu-Chun; Byrnes, Graham; Zaridze, David; Shangina, Oxana; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Rudnai, Peter; Fabianova, Eleonora; Bucur, Alexandru; Bencko, Vladimir; Holcatova, Ivana; Janout, Vladimir; Foretova, Lenka; Lagiou, Pagona; Trichopoulos, Dimitrios; Benhamou, Simone; Bouchardy, Christine; Ahrens, Wolfgang; Merletti, Franco; Richiardi, Lorenzo; Talamini, Renato; Barzan, Luigi; Kjaerheim, Kristina; Macfarlane, Gary J; Macfarlane, Tatiana V; Simonato, Lorenzo; Canova, Cristina; Agudo, Antonio; Castellsagué, Xavier; Lowry, Ray; Conway, David I; McKinney, Patricia A; Healy, Claire M; Toner, Mary E; Znaor, Ariana; Curado, Maria Paula; Koifman, Sergio; Menezes, Ana; Wünsch-Filho, Victor; Neto, José Eluf; Garrote, Leticia Fernández; Boccia, Stefania; Cadoni, Gabriella; Arzani, Dario; Olshan, Andrew F; Weissler, Mark C; Funkhouser, William K; Luo, Jingchun; Lubiński, Jan; Trubicka, Joanna; Lener, Marcin; Oszutowska, Dorota; Schwartz, Stephen M; Chen, Chu; Fish, Sherianne; Doody, David R; Muscat, Joshua E; Lazarus, Philip; Gallagher, Carla J; Chang, Shen-Chih; Zhang, Zuo-Feng; Wei, Qingyi; Sturgis, Erich M; Wang, Li-E; Franceschi, Silvia; Herrero, Rolando; Kelsey, Karl T; McClean, Michael D; Marsit, Carmen J; Nelson, Heather H; Romkes, Marjorie; Buch, Shama; Nukui, Tomoko; Zhong, Shilong; Lacko, Martin; Manni, Johannes J; Peters, Wilbert H M; Hung, Rayjean J; McLaughlin, John; Vatten, Lars; Njølstad, Inger; Goodman, Gary E; Field, John K; Liloglou, Triantafillos; Vineis, Paolo; Clavel-Chapelon, Francoise; Palli, Domenico; Tumino, Rosario; Krogh, Vittorio; Panico, Salvatore; González, Carlos A; Quirós, J Ramón; Martínez, Carmen; Navarro, Carmen; Ardanaz, Eva; Larrañaga, Nerea; Khaw, Kay-Tee; Key, Timothy; Bueno-de-Mesquita, H Bas; Peeters, Petra H M; Trichopoulou, Antonia; Linseisen, Jakob; Boeing, Heiner; Hallmans, Göran; Overvad, Kim; Tjønneland, Anne; Kumle, Merethe; Riboli, Elio; Välk, Kristjan; Vooder, Tõnu; Voodern, Tõnu; Metspalu, Andres; Zelenika, Diana; Boland, Anne; Delepine, Marc; Foglio, Mario; Lechner, Doris; Blanché, Hélène; Gut, Ivo G; Galan, Pilar; Heath, Simon; Hashibe, Mia; Hayes, Richard B; Boffetta, Paolo; Lathrop, Mark; Brennan, Paul

    2011-03-01

    Genome-wide association studies (GWAS) have been successful in identifying common genetic variation involved in susceptibility to etiologically complex disease. We conducted a GWAS to identify common genetic variation involved in susceptibility to upper aero-digestive tract (UADT) cancers. Genome-wide genotyping was carried out using the Illumina HumanHap300 beadchips in 2,091 UADT cancer cases and 3,513 controls from two large European multi-centre UADT cancer studies, as well as 4,821 generic controls. The 19 top-ranked variants were investigated further in an additional 6,514 UADT cancer cases and 7,892 controls of European descent from an additional 13 UADT cancer studies participating in the INHANCE consortium. Five common variants presented evidence for significant association in the combined analysis (p ≤ 5 × 10⁻⁷). Two novel variants were identified, a 4q21 variant (rs1494961, p = 1×10⁻⁸) located near DNA repair related genes HEL308 and FAM175A (or Abraxas) and a 12q24 variant (rs4767364, p =2 × 10⁻⁸) located in an extended linkage disequilibrium region that contains multiple genes including the aldehyde dehydrogenase 2 (ALDH2) gene. Three remaining variants are located in the ADH gene cluster and were identified previously in a candidate gene study involving some of these samples. The association between these three variants and UADT cancers was independently replicated in 5,092 UADT cancer cases and 6,794 controls non-overlapping samples presented here (rs1573496-ADH7, p = 5 × 10⁻⁸); rs1229984-ADH1B, p = 7 × 10⁻⁹; and rs698-ADH1C, p = 0.02). These results implicate two variants at 4q21 and 12q24 and further highlight three ADH variants in UADT cancer susceptibility.

  2. A Genome-Wide Association Study of Upper Aerodigestive Tract Cancers Conducted within the INHANCE Consortium

    PubMed Central

    McKay, James D.; Truong, Therese; Gaborieau, Valerie; Chabrier, Amelie; Chuang, Shu-Chun; Byrnes, Graham; Zaridze, David; Shangina, Oxana; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Rudnai, Peter; Fabianova, Eleonora; Bucur, Alexandru; Bencko, Vladimir; Holcatova, Ivana; Janout, Vladimir; Foretova, Lenka; Lagiou, Pagona; Trichopoulos, Dimitrios; Benhamou, Simone; Bouchardy, Christine; Ahrens, Wolfgang; Merletti, Franco; Richiardi, Lorenzo; Talamini, Renato; Barzan, Luigi; Kjaerheim, Kristina; Macfarlane, Gary J.; Macfarlane, Tatiana V.; Simonato, Lorenzo; Canova, Cristina; Agudo, Antonio; Castellsagué, Xavier; Lowry, Ray; Conway, David I.; McKinney, Patricia A.; Healy, Claire M.; Toner, Mary E.; Znaor, Ariana; Curado, Maria Paula; Koifman, Sergio; Menezes, Ana; Wünsch-Filho, Victor; Neto, José Eluf; Garrote, Leticia Fernández; Boccia, Stefania; Cadoni, Gabriella; Arzani, Dario; Olshan, Andrew F.; Weissler, Mark C.; Funkhouser, William K.; Luo, Jingchun; Lubiński, Jan; Trubicka, Joanna; Lener, Marcin; Oszutowska, Dorota; Schwartz, Stephen M.; Chen, Chu; Fish, Sherianne; Doody, David R.; Muscat, Joshua E.; Lazarus, Philip; Gallagher, Carla J.; Chang, Shen-Chih; Zhang, Zuo-Feng; Wei, Qingyi; Sturgis, Erich M.; Wang, Li-E; Franceschi, Silvia; Herrero, Rolando; Kelsey, Karl T.; McClean, Michael D.; Marsit, Carmen J.; Nelson, Heather H.; Romkes, Marjorie; Buch, Shama; Nukui, Tomoko; Zhong, Shilong; Lacko, Martin; Manni, Johannes J.; Peters, Wilbert H. M.; Hung, Rayjean J.; McLaughlin, John; Vatten, Lars; Njølstad, Inger; Goodman, Gary E.; Field, John K.; Liloglou, Triantafillos; Vineis, Paolo; Clavel-Chapelon, Francoise; Palli, Domenico; Tumino, Rosario; Krogh, Vittorio; Panico, Salvatore; González, Carlos A.; Quirós, J. Ramón; Martínez, Carmen; Navarro, Carmen; Ardanaz, Eva; Larrañaga, Nerea; Khaw, Kay-Tee; Key, Timothy; Bueno-de-Mesquita, H. Bas; Peeters, Petra H. M.; Trichopoulou, Antonia; Linseisen, Jakob; Boeing, Heiner; Hallmans, Göran; Overvad, Kim; Tjønneland, Anne; Kumle, Merethe; Riboli, Elio; Välk, Kristjan; Voodern, Tõnu; Metspalu, Andres; Zelenika, Diana; Boland, Anne; Delepine, Marc; Foglio, Mario; Lechner, Doris; Blanché, Hélène; Gut, Ivo G.; Galan, Pilar; Heath, Simon; Hashibe, Mia; Hayes, Richard B.; Boffetta, Paolo; Lathrop, Mark; Brennan, Paul

    2011-01-01

    Genome-wide association studies (GWAS) have been successful in identifying common genetic variation involved in susceptibility to etiologically complex disease. We conducted a GWAS to identify common genetic variation involved in susceptibility to upper aero-digestive tract (UADT) cancers. Genome-wide genotyping was carried out using the Illumina HumanHap300 beadchips in 2,091 UADT cancer cases and 3,513 controls from two large European multi-centre UADT cancer studies, as well as 4,821 generic controls. The 19 top-ranked variants were investigated further in an additional 6,514 UADT cancer cases and 7,892 controls of European descent from an additional 13 UADT cancer studies participating in the INHANCE consortium. Five common variants presented evidence for significant association in the combined analysis (p≤5×10−7). Two novel variants were identified, a 4q21 variant (rs1494961, p = 1×10−8) located near DNA repair related genes HEL308 and FAM175A (or Abraxas) and a 12q24 variant (rs4767364, p = 2×10−8) located in an extended linkage disequilibrium region that contains multiple genes including the aldehyde dehydrogenase 2 (ALDH2) gene. Three remaining variants are located in the ADH gene cluster and were identified previously in a candidate gene study involving some of these samples. The association between these three variants and UADT cancers was independently replicated in 5,092 UADT cancer cases and 6,794 controls non-overlapping samples presented here (rs1573496-ADH7, p = 5×10−8; rs1229984-ADH1B, p = 7×10−9; and rs698-ADH1C, p = 0.02). These results implicate two variants at 4q21 and 12q24 and further highlight three ADH variants in UADT cancer susceptibility. PMID:21437268

  3. Experimental Study on the Electrical Conductivity of Pyroxene Andesite at High Temperature and High Pressure

    NASA Astrophysics Data System (ADS)

    Hui, KeShi; Dai, LiDong; Li, HePing; Hu, HaiYing; Jiang, JianJun; Sun, WenQing; Zhang, Hui

    2016-09-01

    The electrical conductivity of pyroxene andesite was in situ measured under conditions of 1.0-2.0 GPa and 673-1073 K using a YJ-3000t multi-anvil press and Solartron-1260 Impedance/Gain-phase analyzer. Experimental results indicate that the electrical conductivities of pyroxene andesite increase with increasing temperature, and the electrical conductivities decrease with the rise of pressure, and the relationship between electrical conductivity (σ) and temperature (T) conforms to an Arrhenius relation within a given pressure and temperature range. When temperature rises up to 873-923 K, the electrical conductivities of pyroxene andesite abruptly increase, and the activation enthalpy increases at this range, which demonstrates that pyroxene andesite starts to dehydrate. By the virtue of the activation enthalpy (0.35-0.42 eV) and the activation volume (-6.75 ± 1.67 cm3/mole) which characterizes the electrical properties of sample after dehydration, we consider that the conduction mechanism is the small polaron conduction before and after dehydration, and that the rise of carrier concentration is the most important reason of increased electrical conductivity.

  4. A 30-Year Prospective Follow-Up Study of Hyperactive Boys with Conduct Problems: Adult Criminality

    ERIC Educational Resources Information Center

    Satterfield, James H.; Faller, Katherine J.; Crinella, Francis M.; Schell, Anne M.; Swanson, James M.; Homer, Louis D.

    2007-01-01

    Objective: To compare the official arrest records for a large number of hyperactive boys (N = 179), most with conduct problems, and 75 control boys; to examine childhood IQ, socioeconomic status, and parent reports of childhood hyperactivity and conduct problems for their contribution to criminal behavior in adulthood; and to compare adult outcome…

  5. A Study of Master's Degrees in Orchestral Conducting in the United States

    ERIC Educational Resources Information Center

    St. John, Brian Allen

    2010-01-01

    In order to learn to be an orchestra conductor in the United States of America, students often begins their formal education by seeking to earn a master's degree in orchestral conducting. This project compiled a listing of American universities which offer a master's degree in orchestral conducting and categorized the component parts of their…

  6. Experimental Study on the Electrical Conductivity of Pyroxene Andesite at High Temperature and High Pressure

    NASA Astrophysics Data System (ADS)

    Hui, KeShi; Dai, LiDong; Li, HePing; Hu, HaiYing; Jiang, JianJun; Sun, WenQing; Zhang, Hui

    2017-03-01

    The electrical conductivity of pyroxene andesite was in situ measured under conditions of 1.0-2.0 GPa and 673-1073 K using a YJ-3000t multi-anvil press and Solartron-1260 Impedance/Gain-phase analyzer. Experimental results indicate that the electrical conductivities of pyroxene andesite increase with increasing temperature, and the electrical conductivities decrease with the rise of pressure, and the relationship between electrical conductivity ( σ) and temperature ( T) conforms to an Arrhenius relation within a given pressure and temperature range. When temperature rises up to 873-923 K, the electrical conductivities of pyroxene andesite abruptly increase, and the activation enthalpy increases at this range, which demonstrates that pyroxene andesite starts to dehydrate. By the virtue of the activation enthalpy (0.35-0.42 eV) and the activation volume (-6.75 ± 1.67 cm3/mole) which characterizes the electrical properties of sample after dehydration, we consider that the conduction mechanism is the small polaron conduction before and after dehydration, and that the rise of carrier concentration is the most important reason of increased electrical conductivity.

  7. On the Feasibility of Conducting Randomised Trials in Education: Case Study of a Sex Education Intervention

    ERIC Educational Resources Information Center

    Moore, Laurence; Graham, Anna; Diamond, Ian

    2003-01-01

    This article reports on the conduct and results of a randomised controlled trial to test the effectiveness of a teacher-led intervention to improve teenagers' knowledge of emergency contraception. The trial was successfully conducted in 24 mixed-sex state secondary schools in Avon, South-west England. The intervention was popular with both…

  8. Case-control studies of sporadic enteric infections: a review and discussion of studies conducted internationally from 1990 to 2009.

    PubMed

    Fullerton, Kathleen E; Scallan, Elaine; Kirk, Martyn D; Mahon, Barbara E; Angulo, Frederick J; de Valk, Henriette; van Pelt, Wilfrid; Gauci, Charmaine; Hauri, Anja M; Majowicz, Shannon; O'Brien, Sarah J

    2012-04-01

    Epidemiologists have used case-control studies to investigate enteric disease outbreaks for many decades. Increasingly, case-control studies are also used to investigate risk factors for sporadic (not outbreak-associated) disease. While the same basic approach is used, there are important differences between outbreak and sporadic disease settings that need to be considered in the design and implementation of the case-control study for sporadic disease. Through the International Collaboration on Enteric Disease "Burden of Illness" Studies (the International Collaboration), we reviewed 79 case-control studies of sporadic enteric infections caused by nine pathogens that were conducted in 22 countries and published from 1990 through to 2009. We highlight important methodological and study design issues (including case definition, control selection, and exposure assessment) and discuss how approaches to the study of sporadic enteric disease have changed over the last 20 years (e.g., making use of more sensitive case definitions, databases of controls, and computer-assisted interviewing). As our understanding of sporadic enteric infections grows, methods and topics for case-control studies are expected to continue to evolve; for example, advances in understanding of the role of immunity can be used to improve control selection, the apparent protective effects of certain foods can be further explored, and case-control studies can be used to provide population-based measures of the burden of disease.

  9. An International Round-Robin Study, Part II: Thermal Diffusivity, Specific Heat and Thermal Conductivity

    SciTech Connect

    Wang, Hsin; Porter, Wallace D; Bottner, Harold; Konig, Jan; Chen, Lidong; Bai, Shengqiang; Tritt, Terry M.; Mayolett, Alex; Senawiratne, Jayantha; Smith, Charlene; Harris, Fred; Gilbert, Partricia; Sharp, J; Lo, Jason; Keinke, Holger; Kiss, Laszlo I.

    2013-01-01

    For bulk thermoelectrics, figure-of-merit, ZT, still needs to improve from the current value of 1.0 - 1.5 to above 2 to be competitive to other alternative technologies. In recent years, the most significant improvements in ZT were mainly due to successful reduction of thermal conductivity. However, thermal conductivity cannot be measured directly at high temperatures. The combined measurements of thermal diffusivity and specific heat and density are required. It has been shown that thermal conductivity is the property with the greatest uncertainty and has a direct influence on the accuracy of the figure of merit. The International Energy Agency (IEA) group under the implementing agreement for Advanced Materials for Transportation (AMT) has conducted two international round-robins since 2009. This paper is Part II of the international round-robin testing of transport properties of bulk bismuth telluride. The main focuses in Part II are on thermal diffusivity, specific heat and thermal conductivity.

  10. Pathology Working Group review and evaluation of proliferative lesions of mammary gland tissues in female rats fed ammonium perfluorooctanoate (APFO) in the diet for 2 years.

    PubMed

    Hardisty, Jerry F; Willson, Gabrielle A; Brown, W Ray; McConnell, Ernest E; Frame, Steven R; Gaylor, David W; Kennedy, Gerald L; Butenhoff, John L

    2010-04-01

    Perfluorooctanoate (PFO) is a perfluorinated carboxylate that is widely distributed in the environment. A 2-year chronic study was conducted in rats fed either 30 or 300 ppm of ammonium perfluorooctanoate (APFO). To investigate the possible relationship of APFO exposure to proliferative mammary lesions, a Pathology Working Group (PWG) review of the original slides was performed. The consensus reached by the PWG was that the incidence of mammary-gland neoplasms was not affected by chronic dietary administration of APFO. Therefore, feeding female rats up to 300 ppm of APFO resulted in no increase in proliferative lesions of the mammary tissue.

  11. 77 FR 60441 - Pediatric Studies of Sodium Nitroprusside Conducted in Accordance With Section 409I of the Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... HUMAN SERVICES Food and Drug Administration Pediatric Studies of Sodium Nitroprusside Conducted in... of sodium nitroprusside that were conducted in accordance with the Public Health Service Act (the PHS.... 107-109), the priority list included specific drugs instead of therapeutic areas. Sodium...

  12. Conduct Disorder Symptoms and Subsequent Pregnancy, Child-Birth and Abortion: A Population-Based Longitudinal Study of Adolescents

    ERIC Educational Resources Information Center

    Pedersen, Willy; Mastekaasa, Arne

    2011-01-01

    Research on teenage pregnancy and abortion has primarily focused on socio-economic disadvantage. However, a few studies suggest that risk of unwanted pregnancy is related to conduct disorder symptoms. We examined the relationship between level of conduct disorder symptoms at age 15 and subsequent pregnancy, child-birth and abortion. A…

  13. Numerical study of magnetoacoustic signal generation with magnetic induction based on inhomogeneous conductivity anisotropy.

    PubMed

    Li, Xun; Hu, Sanqing; Li, Lihua; Zhu, Shanan

    2013-01-01

    Magnetoacoustic tomography with magnetic induction (MAT-MI) is a noninvasive imaging modality for generating electrical conductivity images of biological tissues with high spatial resolution. In this paper, we create a numerical model, including a permanent magnet, a coil, and a two-layer coaxial cylinder with anisotropic electrical conductivities, for the MAT-MI forward problem. We analyze the MAT-MI sources in two cases, on a thin conductive boundary layer and in a homogeneous medium, and then develop a feasible numerical approach to solve the MAT-MI sound source densities in the anisotropic conductive model based on finite element analysis of electromagnetic field. Using the numerical finite element method, we then investigate the magnetoacoustic effect of anisotropic conductivity under the inhomogeneous static magnetic field and inhomogeneous magnetic field, quantitatively compute the boundary source densities in the conductive model, and calculate the sound pressure. The anisotropic conductivity contributes to the distribution of the eddy current density, Lorentz force density, and acoustic signal. The proposed models and approaches provide a more realistic simulation environment for MAT-MI.

  14. Study of thermal conductivity enhancement of aqueous suspensions containing silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Iyahraja, S.; Rajadurai, J. Selwin

    2015-05-01

    Nanofluids are prepared by dispersing polyvinylpyrrolidone coated silver nanoparticles in distilled water. The thermal conductivity of nanofluids is measured by KD2 Pro thermal analyzer which is based on transient hot wire method. The influence of size and concentration of nanoparticles, surfactant and temperature of suspensions on the enhancement of the thermal conductivity is analyzed. The experimental results show that the thermal conductivity of nanofluids increases with the decrease in the size and increase in the concentration of the nanoparticles. Even with low volume fraction of 0.1 % and 20 nm size of silver nanoparticles, a high thermal conductivity enhancement of 54 % has been achieved. The surfactant and the temperature have a significant effect on the thermal conductivity enhancement of the nanofluids. The increase in temperature of the nanofluid from 30oC to 60oC increases its thermal conductivity up to 69 % whereas the addition of surfactant lessens the thermal conductivity enhancement to 34.2% with polyvinylpyrrolidone and 31.5 % with sodium dodecyl sulfate. The experimental results are compared with the existing theoretical models.

  15. Validation of a one-stop carpal tunnel clinic including nerve conduction studies and hand therapy

    PubMed Central

    Ball, C; Pearse, M; Kennedy, D; Hall, A; Nanchahal, J

    2011-01-01

    INTRODUCTION Carpal tunnel syndrome is the most common hand disorder. We describe a pathway that includes clinical assessment, neurophysiological testing, surgery and physical therapy all at the same visit. METHODS All referrals for carpal tunnel syndrome were screened for inclusion in a ‘one-stop’ surgeon-led clinic. Prospective clinical data collected included patient reported outcome measures and satisfaction scores, touch threshold, pinch and grip strength. Patients were assessed clinically, underwent nerve conduction studies and surgery as indicated, all on the same day. Baseline and one-year follow-up data were analysed for 57 patients (62 hands). RESULTS There was significant improvement in all domains of the Boston Carpal Tunnel and Michigan Hand Outcomes questionnaires, grip strength and touch threshold. There were no adverse events. The total mean operating time was 12.8 minutes (range: 5–15 minutes) and the mean tourniquet time was 2.5 minutes (range: 1–11 minutes). Using a dual theatre model produced a short mean turnaround time of 14.8 minutes (range: 2–37 minutes). Patient satisfaction as judged using a Picker questionnaire was very high. CONCLUSIONS A highly efficient clinical service involving both diagnostics and treatment can be delivered at a single hospital visit while maintaining optimal outcomes and high patient satisfaction. PMID:22041242

  16. Studies on the defluoridation of water using conducting polymer/montmorillonite composites.

    PubMed

    Karthikeyan, M; Kumar, K K Satheesh; Elango, K P

    2012-01-01

    Conducting polymer/inorganic hybrid composites have large surface areas, which makes the adsorbent properties of the polymer composites as good the constituents. Polyaniline/montmorilonite (PANi-MMT) and polypyrrole/montmorillonite (PPy-MMT) composites were prepared, characterized (Fourier transform infrared, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction patterns) and were employed as adsorbents for the removal of fluoride ions from aqueous solution by the batch sorption method. The spectral studies of the adsorbents before and after the adsorption are recorded to get better insight into the mechanism of the adsorption process. The results indicated that the removal of fluoride ions from water by these composites occurs via the combined effect of both the constituents, that is, through a physico-chemical mechanism. The amount of fluoride ion adsorbed by PANi-MMT and PPy-MMT at 30 degrees C is observed to be 2.3 and 5.1 mg g(-1), respectively, when compared to 0.77 and 2.66 mg g(-1), respectively, for the polymers alone. The Langmuir, Freundlich and Dubinin-Radushkevich isotherms were used to describe the adsorption equilibrium.

  17. A Unified Frequency Domain Model to Study the Effect of Demyelination on Axonal Conduction

    PubMed Central

    Chaubey, Saurabh; Goodwin, Shikha J.

    2016-01-01

    Multiple sclerosis is a disease caused by demyelination of nerve fibers. In order to determine the loss of signal with the percentage of demyelination, we need to develop models that can simulate this effect. Existing time-based models does not provide a method to determine the influences of demyelination based on simulation results. Our goal is to develop a system identification approach to generate a transfer function in the frequency domain. The idea is to create a unified modeling approach for neural action potential propagation along the length of an axon containing number of Nodes of Ranvier (N). A system identification approach has been used to identify a transfer function of the classical Hodgkin–Huxley equations for membrane voltage potential. Using this approach, we model cable properties and signal propagation along the length of the axon with N node myelination. MATLAB/Simulink platform is used to analyze an N node-myelinated neuronal axon. The ability to transfer function in the frequency domain will help reduce effort and will give a much more realistic feel when compared to the classical time-based approach. Once a transfer function is identified, the conduction as a cascade of each linear time invariant system-based transfer function can be modeled. Using this approach, future studies can model the loss of myelin in various parts of nervous system. PMID:27103847

  18. A Unified Frequency Domain Model to Study the Effect of Demyelination on Axonal Conduction.

    PubMed

    Chaubey, Saurabh; Goodwin, Shikha J

    2016-01-01

    Multiple sclerosis is a disease caused by demyelination of nerve fibers. In order to determine the loss of signal with the percentage of demyelination, we need to develop models that can simulate this effect. Existing time-based models does not provide a method to determine the influences of demyelination based on simulation results. Our goal is to develop a system identification approach to generate a transfer function in the frequency domain. The idea is to create a unified modeling approach for neural action potential propagation along the length of an axon containing number of Nodes of Ranvier (N). A system identification approach has been used to identify a transfer function of the classical Hodgkin-Huxley equations for membrane voltage potential. Using this approach, we model cable properties and signal propagation along the length of the axon with N node myelination. MATLAB/Simulink platform is used to analyze an N node-myelinated neuronal axon. The ability to transfer function in the frequency domain will help reduce effort and will give a much more realistic feel when compared to the classical time-based approach. Once a transfer function is identified, the conduction as a cascade of each linear time invariant system-based transfer function can be modeled. Using this approach, future studies can model the loss of myelin in various parts of nervous system.

  19. Study of a guarded electrode system in the dc conductivity measurement of insulating liquid

    NASA Astrophysics Data System (ADS)

    Zhou, Yuan; Hao, Miao; Chen, George; Wilson, Gordon; Jarman, Paul

    2014-07-01

    The design and choice of an electrode system is important in dc conductivity measurement of insulating liquid. In this paper, the electric field distribution of an electrode system which consists of two parallel circular metallic electrodes and a guard electrode has been studied using Comsol Multiphysics software. A new parameter, which is not yet involved in current standards, the edge radius, has been mentioned in the literature formerly and is currently discussed in a CIGRE working group. In this paper, the influence of this parameter has been investigated by means of field calculation. As seen from the simulating result, there are regions in the vicinity of the edges of the guard and measuring electrode that are under high electric field. If the edges of these two electrodes are sharp, the maximum electric field in the test cell will be much higher than the average field between the measuring electrode and the high voltage electrode. An empirical equation has been proposed to calculate this maximum field. The classic correction expression for an effective radius has been re-evaluated with the edge radius being taken into account. Experimental work has been performed to confirm this conclusion. Three kinds of mineral oils with different ageing times have been tested under the dc field using a guarded electrode system and the electric strengths of these oils have been estimated. A recommendation has been made to current standards in insulating liquid measurement.

  20. The Heritability of the Skin Conductance Orienting Response: A Longitudinal Twin Study

    PubMed Central

    Tuvblad, Catherine; Gao, Yu; Isen, Joshua; Botwick, Theodore; Raine, Adrian; Baker, Laura A.

    2011-01-01

    The orienting response is a widely used experimental paradigm that reflects the association between electrodermal activity and psychological processes. The present study examined the genetic and environmental etiology of skin conductance orienting response (SCOR) magnitude in a sample of twins assessed at ages 9-10, 11-13 and 14-16 years. Structural equation modeling at each visit showed that genetic influences explained 56%, 83%, and 48% of the total variance in SCOR at visit 1, 2, and 3 respectively, with the remaining variance explained by non-shared environmental factors. SCOR was moderately stable across ages, with phenotypic correlations between time points ranging from .35 to .45. A common genetic factor explained 36%, 45% and 49% of the variance in SCOR magnitude across development. Additional age-specific genetic effects were found at ages 9-10 and 11-13 years, explaining 18% and 35% of the variance, respectively. The genetic correlations among the three time points were high, ranging from .55 to .73, indicating a substantial continuity in genetic influences from ages 9 to 16. These findings suggest that genetic factors are important influences in SCOR magnitude during late childhood and adolescence. PMID:21945549