WorldWideScience

Sample records for bifida sb epidemiological

  1. Ultrasound in Prenatal Diagnostics and Its Impact on the Epidemiology of Spina Bifida in a National Cohort from Denmark with a Comparison to Sweden

    DEFF Research Database (Denmark)

    Bodin, Charlotte; Rasmussen, Mikkel Mylius; Tabor, Ann

    2018-01-01

    Objectives: The aim of this study was to assess the incidence, the prenatal detection rate by ultrasound, and the pregnancy outcome of spina bifida (SB) in Denmark (DK) in 2008-2015 and to compare results to national data from Sweden. Methods: Data were retrieved from the Danish Fetal Medicine Da...

  2. Osteoporosis in paediatric patients with spina bifida

    OpenAIRE

    Marreiros, Humberto; Loff, Clara; Calado, Eulalia

    2012-01-01

    The prevalence andmorbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified. Objective: To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state...

  3. Restrictions in social participation of young adults with spina bifida

    NARCIS (Netherlands)

    Barf, H. A.; Post, M. W. M.; Verhoef, M.; Jennekens-Schinkel, A.; Gooskens, R. H. J. M.; Prevo, A. J. H.

    2009-01-01

    Purpose. To determine participation restrictions of young adults with spina bifida (SB) in relation to health condition and activity limitations. Method. A total of 179 persons aged 16-25 years and born with SB participated in a cross-sectional study. The main outcome on four domains of

  4. Life satisfaction of young adults with spina bifida

    NARCIS (Netherlands)

    Barf, H. A.; Post, M. W. M.; Verhoef, M.; Jennekens-Schinkel, A.; Gooskens, R. H. J. M.; Prevo, A. J. H.

    This study concerns life satisfaction and its determinants in Dutch young adults with spina bifida (SB). Data on life satisfaction (Life Satisfaction Questionnaire [LiSat-9]) were related to hydrocephalus, lesion level, disabilities, and demographic variables. In total, 179 young adults with SB

  5. Predominant bacteria and patterns of antibiotic susceptibility in urinary tract infection in children with spina bifida.

    Science.gov (United States)

    Ortiz, Tara K; Velazquez, Nermarie; Ding, Laura; Routh, Jonathan C; Wiener, John S; Seed, Patrick C; Ross, Sherry S

    2018-04-20

    Urinary tract infection is more common in children with spina bifida (SB) than neurologically intact children, and Escherichiacoli is the most common urinary pathogen in the general pediatric population. Less is known of the pathogens responsible for urinary tract infections (UTI) in the pediatric SB population or their evolving antimicrobial resistance patterns. The goal of this study is to determine the epidemiology and antimicrobial resistance patterns of SB-associated urinary pathogens. Between January 1996 and August 2013, 231 patients aged 1 month to 18 years were identified with a diagnosis of SB-NB and at least one symptomatic urinary tract infection (UTI) event (Table). Two-hundred and thirty-one normally voiding children with a single symptomatic UTI were age-matched based on age at diagnosis of UTI at a 1:1 ratio. Chi-square tests and Generalized Estimating Equation analysis, controlling for clinicopathological factors, were performed to compare rates of pathogen-associations with UTI between groups and likelihood of UTI with multi-drug resistant (MDR) organisms. Children in the SB-NB group had a higher rate of non-E. coli UTI compared with controls (64% vs. 41%, p Children with SB-NB are more likely to have non-E. coli UTI, UTIs with MDR organisms, and urosepsis than the general pediatric population. Published by Elsevier Ltd.

  6. Spina Bifida Cystica

    African Journals Online (AJOL)

    andrew

    2012-01-20

    Jan 20, 2012 ... disability of the infant. The prevalence of Spina Bifida varies across time, region, race and ... Family history of Spina Bifida was present in 7.8%. Nearly all patients (98%) had myelomeningocele with a most ... Birth ranking was ascertained by history provided by the mother, miscarriages before 28 weeks.

  7. Spina Bifida. Fact Sheet = Espina Bifida. Hojas Informativas Sobre Discapacidades.

    Science.gov (United States)

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet offers definitions of the three types of spina bifida (spina bifida occulta, meningocele, and myelomeningocele), outlines their incidence, describes characteristics of individuals with spina bifida, and reviews educational implications. The fact sheet discusses the need for many children with myelomeningocele to learn to manage…

  8. Spina Bifida Data and Statistics

    Science.gov (United States)

    ... Us Information For… Media Policy Makers Data and Statistics Recommend on Facebook Tweet Share Compartir Spina bifida ... the spine. Read below for the latest national statistics on spina bifida in the United States. In ...

  9. Osteoporosis in paediatric patients with spina bifida.

    Science.gov (United States)

    Marreiros, Humberto; Marreiros, Humberto Filipe; Loff, Clara; Calado, Eulalia

    2012-01-01

    The prevalence and morbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified. To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis. Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury. Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

  10. Factors Associated With Pressure Ulcers in Individuals With Spina Bifida

    Science.gov (United States)

    Kim, Sunkyung; Ward, Elisabeth; Dicianno, Brad E.; Clayton, Gerald H.; Sawin, Kathleen J.; Beierwaltes, Patricia; Thibadeau, Judy

    2015-01-01

    Objective To describe factors associated with pressure ulcers in individuals with spina bifida (SB) enrolled in the National Spina Bifida Patient Registry (NSBPR). Design Unbalanced longitudinal multicenter cohort study. Setting Nineteen SB clinics. Participants Individuals with SB (N=3153) enrolled in 19 clinic sites that participate in the NSBPR. Interventions Not applicable. Main Outcome Measures Pressure ulcer status (yes/no) at the annual visit between 2009 and 2012. Results Of 3153 total participants, 19% (n=603) reported ulcers at their most recent annual clinic visit. Seven factors–level of lesion, wheelchair use, urinary incontinence, shunt presence, above the knee orthopedic surgery, recent surgery, and male sex–were significantly associated with the presence of pressure ulcers. Of these factors, level of lesion, urinary incontinence, recent surgery, and male sex were included in the final logistic regression model. The 3 adjusting variables–SB type, SB clinic, and age group–were significant in all analyses (all Ppressure ulcers. Identifying key factors associated with the onset of pressure ulcers can be incorporated into clinical practice in ways that prevent and enhance treatment of pressure ulcers in the population with SB. PMID:25796136

  11. Spina Bifida Clinic Directory

    Science.gov (United States)

    ... 7th Avenue S. Birmingham, AL 35233 (205) 939-5281 https://www.childrensal.org/SpinaBifidaProgram UAB Spain Rehab Adult ... Ave S Birmingham, AL 35249 Phone: (205) 934-4131 http://www.uabmedicine.org/locations/spain-rehabilitation-center Children’s ...

  12. Spina bifida and sexuality

    DEFF Research Database (Denmark)

    von Linstow, Michael Ernst; Biering-Sørensen, Ida; Liebach, Annette

    2014-01-01

    , neurological examination, personal interview, Functional Independence Measure (FIMTM), Medical Outcome Study Short Form 36 (SF-36) on quality of life, and questions on sexual function and related topics. Study cohort: Fifty-three participants (27 women, 26 men) with spina bifida (mean age 27.1, range 18......OBJECTIVE: To evaluate sexual function amongst adult individuals with spina bifida and to register their subjective satisfaction with their sexual life and relationships. SETTING: Department for Spinal Cord Injuries, East Denmark. STUDY DESIGN AND METHODS: Cohort study. Medical record information......-35) years. Response rate 74%. RESULTS: Fifty-one percent of subjects regarded their sexual life as a failure or dysfunctional. However, 45% reported being satisfied with their sexual life. Participants with partners were more satisfied with their sexual life than those without partners. Faecal...

  13. Spina bifida and parental occupation

    NARCIS (Netherlands)

    Blatter, B.M.

    1997-01-01

    The aims of this thesis were: (1) to identify parental occupations with an increased risk of spina bifida in offspring; (2) to study whether parental occupational exposure to chemicals or radiation during or shortly before pregnancy is a risk factor for the occurrence of spina bifida. In order to

  14. Physical fitness and physical behavior in (wheelchair-using) youth with spina bifida

    NARCIS (Netherlands)

    Bloemen, M.A.T.

    2017-01-01

    Associations between low physical fitness, unfavorable physical behavior and higher cardiovascular and overall mortality are well known. Children with a physical disability like spina bifida (SB) are at high risk of decreased levels of physical fitness and unfavorable physical behavior. They seem to

  15. Physical fitness, ambulation en physical activity in ambulatory children with spina bifida

    NARCIS (Netherlands)

    Groot, J.F. de

    2010-01-01

    Children with chronic disease or child-onset disability, like Spina Bifida (SB) are at increased risk of being inactive. Earlier studies in adolescents and young adults, have found correlations between an inactive lifestyle and lower levels of aerobic fitness. A second important issue being raised

  16. Daily time management in children with spina bifida.

    Science.gov (United States)

    Persson, Marika; Janeslätt, Gunnel; Peny-Dahlstrand, Marie

    2017-12-11

    Spina bifida (SB) often results in a complex disability and can also cause cognitive dysfunction. No previous study has investigated the ability to adapt to time in children with SB. This ability is crucial for an individual's possibility to develop autonomy in life. The purpose of this study was to investigate whether children aged 10-17 with SB have lower time-processing abilities than typically-developing children, and to describe the profile of time-processing in children with SB. Participants comprised a consecutive sample of 21 children (drawn from a geographical cohort of 45) aged 10-17 years (mean: 14 years, SD: 2 years); 13 were boys. The instruments used were KaTid-Y, Time-S, and Time-P. The children with SB had lower time-processing abilities than typically-developing children (52.4% under -2SD), particularly difficulties to orient to and to estimate objective time, to understand time perspectives and with time planning. They also self-rated low use of strategies to adapt to time. The parents rated their children as having extensive difficulties in daily time management. The low time-processing ability found in children with SB is likely to be an important contributing factor to low autonomy and independence.

  17. Validity and reliability of skill-related fitness tests for wheelchair-using youth with Spina Bifida.

    NARCIS (Netherlands)

    Bloemen, M.A.; Takken, T.; Backx, F.J.; Vos, M.; Kruitwagen, C.L.; Groot, J.F. de

    2017-01-01

    Objectives: To determine content validity of the Muscle Power Sprint Test (MPST), and construct validity and reliability of the MPST, 10x5 Meter Sprint Test (10x5MST), slalom test, and One Stroke Push Test (1SPT) in wheelchair-using youth with spina bifida (SB). Design: Clinimetric study. Setting:

  18. Central Somatosensory Networks Respond to a De Novo Innervated Penis : A Proof of Concept in Three Spina Bifida Patients

    NARCIS (Netherlands)

    Kortekaas, Rudie; Nanetti, Luca; Overgoor, Max L. E.; de Jong, Bauke M.; Georgiadis, Janniko R.

    Introduction. Spina bifida (SB) causes low spinal lesions, and patients often have absent genital sensation and a highly impaired sex life. TOMAX (TO MAX-imize sensation, sexuality and quality of life) is a surgical procedure whereby the penis is newly innervated using a sensory nerve originally

  19. Validity and Reliability of Skill-Related Fitness Tests for Wheelchair-Using Youth With Spina Bifida

    NARCIS (Netherlands)

    Bloemen, Manon A.; Takken, Tim; Backx, Frank J.; Vos, Marleen; Kruitwagen, Cas L.; de Groot, Janke F.

    OBJECTIVE: To determine content validity of the Muscle Power Sprint Test (MPST) and construct validity and reliability of the MPST, 10x5 Meter Sprint Test (10x5MST), slalom test and one stroke push test (1SPT) in wheelchair-using youth with spina bifida (SB). DESIGN: Clinimetric study SETTING:

  20. Validity and Reliability of Skill-Related Fitness Tests for Wheelchair-Using Youth with Spina Bifida

    NARCIS (Netherlands)

    Cas L.J.J. Kruitwagen; Frank J.G. Backx; Tim Takken; Janke de Groot; Marleen Vos; Manon A.T. Bloemen

    2016-01-01

    Objective: To determine content validity of the Muscle Power Sprint Test (MPST) and construct validity and reliability of the MPST, 10x5 Meter Sprint Test (10x5MST), slalom test and one stroke push test (1SPT) in wheelchair-using youth with spina bifida (SB). Design: Clinimetric study Setting:

  1. Motor contingency learning and infants with Spina Bifida.

    Science.gov (United States)

    Taylor, Heather B; Barnes, Marcia A; Landry, Susan H; Swank, Paul; Fletcher, Jack M; Huang, Furong

    2013-02-01

    Infants with Spina Bifida (SB) were compared to typically developing infants (TD) using a conjugate reinforcement paradigm at 6 months-of-age (n = 98) to evaluate learning, and retention of a sensory-motor contingency. Analyses evaluated infant arm-waving rates at baseline (wrist not tethered to mobile), during acquisition of the sensory-motor contingency (wrist tethered), and immediately after the acquisition phase and then after a delay (wrist not tethered), controlling for arm reaching ability, gestational age, and socioeconomic status. Although both groups responded to the contingency with increased arm-waving from baseline to acquisition, 15% to 29% fewer infants with SB than TD were found to learn the contingency depending on the criterion used to determine contingency learning. In addition, infants with SB who had learned the contingency had more difficulty retaining the contingency over time when sensory feedback was absent. The findings suggest that infants with SB do not learn motor contingencies as easily or at the same rate as TD infants, and are more likely to decrease motor responses when sensory feedback is absent. Results are discussed with reference to research on contingency learning in infants with and without neurodevelopmental disorders, and with reference to motor learning in school-age children with SB.

  2. Virtual socialization in adults with spina bifida.

    Science.gov (United States)

    Chan, Wendy M; Dicianno, Brad E

    2011-03-01

    To use spina bifida (SB) as a model of chronic physical disability to study the associations of virtual socialization, friendships, and quality of life (QOL) in adults. Cross-sectional survey. Subjects were recruited from residential living facilities, outpatient clinics, and the University of Pittsburgh Medical Center (UPMC) research registry. Inclusion criteria were age between 18 and 80 years and clinical diagnoses of SB cystica (myelomeningocele) and hydrocephalus. The exclusion criterion was the diagnosis of SB occulta. Sixty-three eligible adults were enrolled, and all completed the study. The survey via questionnaire was performed in person or over the telephone. Data collected included the World Health Organization's Medical Outcomes Study 26-item Short Form, Economic Self-Sufficiency from the Craig Handicap Assessment and Reporting Technique Short Form, virtual socializing habits, and number of friends. Three linear regression models were performed, each with a unique dependent variable: number of friends, psychological QOL, or social QOL. The following independent variables were included in all models: age, gender, ethnicity, economic self-sufficiency, marital status, education level, lesion level, health status, user group, collection method, and time spent virtually socializing. In addition, each regression model included the dependent variables from the other 2 models in its independent variables. Increased degree of virtual socialization (VS) was associated with a greater number of friends (P = .003, r = .684). Mean (standard deviation) numbers of friends by VS groups were the following: users, n = 4.9 ± 2.7; semi-users, n = 3.8 ± 2.7; and nonusers, n = 2.1 ± 2.3, which represent a 2.3 times greater number of friends between the users and nonusers. The effect of virtual socialization on QOL was also positive, however, not statistically significant. People with chronic physical disabilities, such as SB, are at high risk for peer rejection and long

  3. Spina Bifida: General Information. Fact Sheet Number 12 = La Espina Bifida: Informacion General. Fact Sheet Number 21.

    Science.gov (United States)

    Interstate Research Associates, McLean, VA.

    This fact sheet on spina bifida is offered in both English and Spanish. It provides definitions of the three types of spina bifida (spina bifida occulta, meningocele, and myelomeningocele). Incidence figures are given as are typical characteristics of children with spina bifida. Educational implications are briefly noted, including the need to…

  4. Spina Bifida. NICHCY Disability Fact Sheet #12

    Science.gov (United States)

    National Dissemination Center for Children with Disabilities, 2011

    2011-01-01

    "Spina bifida" is one of the most common birth defects in the United States, affecting some 1,500 babies each year. Spina bifida happens during the first month or so of pregnancy and means that the baby's spine did not close completely. Damage to the nerves and the spinal cord may result. Following a brief story about a child with a…

  5. Functional aspects of spina bifida in childhood

    NARCIS (Netherlands)

    Schoenmakers, Maria Adriana Gerdina Cornelia

    2003-01-01

    Due to advanced medical treatment, more children with spina bifida survive into adulthood. Most outcome studies in the field of spina bifida research focus on disease aspects (‘pathology’) and its relation to one of the domains in the ‘disablement process’ such as physical functioning, cognitive

  6. Adolescent predictors of emerging adulthood milestones in youth with spina bifida.

    Science.gov (United States)

    Zukerman, Jill M; Devine, Katie A; Holmbeck, Grayson N

    2011-04-01

    To examine the predictive utility of demographic (illness status and SES), individual (neurocognitive functioning and intrinsic motivation), and family-based (parental intrusiveness) factors during adolescence on the achievement of emerging adulthood milestones in youth with and without spina bifida (SB). Questionnaire and observational data were collected from 14/15-year-old adolescents with SB, typically developing peers, mothers, and teachers. Emerging adulthood milestones (i.e., leaving home, attending college, employment, romantic relationship experience, and number of friendships) were assessed at ages 18/19 years in the full sample and subset of youth who graduated from high school. Typically, developing youth were more likely to achieve milestones compared to youth with SB in the full sample but not when only high school graduates were compared. Executive function, SES, intrinsic motivation, and parental intrusiveness emerged as significant predictors for particular milestones. Interventions targeting executive function, intrinsic motivation, and parenting behavior may facilitate achievement of emerging adulthood milestones.

  7. Sexual identity and orientation in adult men and women with spina bifida.

    Science.gov (United States)

    Szymanski, Konrad M; Hensel, Devon J; Wiener, John S; Whittam, Benjamin; Cain, Mark P; Misseri, Rosalia

    2017-12-11

    Sexuality has received little attention in spina bifida (SB) care. The aim of this study was to assess sexual identity and orientation in adults with SB. An international online survey to adults with SB was administered over 10-months (recruitment: SB clinics, SB organizations via social media). Collected data included demographics, sexual identity and orientation. Non-parametric tests were used for analysis. Median age of 77 men and 119 women was 35 years old (52.0% shunted, 48.5% community ambulators, 42.3% outside United States). Most commonly, men identified as male (96.1%), while 1.3% each described themselves as female, transgender and other. All women reporting sexual identity identified as female (99.2%), 0.8% not providing an answer. Most men reported heterosexual orientation (89.6%), followed by gay (7.8%) and bisexual (2.6%). Most women reported heterosexual orientation (84.9%), followed by bisexual (10.4%), gay/lesbian (2.5%), asexual (0.8%) and other (1.7%). As in the general population, sexual identity typically coincides with biological gender. Sexual orientation of adults with SB mirrors the general population. Due to self-selection, these findings likely do not reflect exact prevalence in the SB population.

  8. Frequently Asked Questions about Spina Bifida

    Science.gov (United States)

    ... and internet sites that offer free and for purchase personal health records, go the The American Health ... team is a high-risk pregnancy specialist with experience managing a Spina Bifida pregnancy. Babies with myelomeningocele, ...

  9. Perineal Sensation Predictive of Spina Bifida Outcome

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2007-01-01

    Full Text Available Neurologic examination, including perineal sensation, was conducted in a prospective cohort study of 117 consecutive patients with open spina bifida at St George's, University of London, and Addenbrooke's Hospital, Cambridge, UK.

  10. Test Your Knowledge of Spina Bifida

    Science.gov (United States)

    ... specialize in spina bifida, to high health care costs from frequent surgeries and hospitalizations. Centers for Disease Control and Prevention (CDC) projects improve the quality of life and encourage full participation at every ...

  11. Bowel Management and Quality of Life in Children With Spina Bifida in South Korea.

    Science.gov (United States)

    Choi, Eun Kyoung; Im, Young Jae; Han, Sang Won

    Bowel management is a concern in patients with spina bifida. We evaluated the status of bowel management in children with spina bifida (SB) and the effects on quality of life (QoL) of children and their caregivers. Data were collected from 173 children with SB between January and June 2011, whose bowel management status and QoL were assessed using a self-administered questionnaire. Of the 173 children, 38 (22.0%) reported normal defecation, 73 (42.2%) reported constipation only, and 62 (35.8%) reported fecal incontinence with/without constipation. For defecation, 59 children (34.1%) used digital stimulation or manual extraction, 28 (16.2%) used suppositories or enemas, 35 (20.3%) used laxatives, 4 (2.3%) used an antegrade continence enema, and 3 (1.7%) used transanal irrigation. There were significant differences in QoL, depending on defecation symptoms. Children with fecal incontinence and their caregivers had difficulties in travel and socialization (p children with SB and their caregivers. Therefore, more attention should be paid to bowel problems and help should be provided to children and their caregivers to improve QoL.

  12. Is continence status associated with quality of life in young children with spina bifida?

    Science.gov (United States)

    Freeman, Kurt A; Smith, Kathryn; Adams, Elizabeth; Mizokawa, Stacey; Neville-Jan, Ann

    2013-01-01

    To evaluate the relationship between child- and parent-reported quality of life (QOL) and bowel and bladder continence among young children with spina bifida (SB). 104 children ages 5-12 years and one of their parents/guardians completed the Pediatric Quality of Life Inventory - Generic Form (PedsQL; parent and child) and the Quality of Life in Spina Bifida Questionnaire (QOLSBQ, parent only). Data on continence, child age, and condition-specific variables were obtained by chart review. Parent and child QOL scores (on all measures of QOL) were positively correlated; parents rated child QOL lower than children's self report. QOL scores did not differ based on continence status. Total PedsQL scores were associated with age and mobility based on child report and with mobility based on parent report. QOL may not be affected by continence status among young children with SB, though demographic (i.e., age) and condition-specific (i.e., functional mobility status) variables appear relevant. Additional research is needed to further evaluate condition-specific variables, other protective variables, and possible measurement issues that influence QOL in young children with SB.

  13. Presurgical assessment of spina bifida

    International Nuclear Information System (INIS)

    Stack, J.P.; Fitzgerald, P.; Redmond, O.; Ennis, J.T.

    1989-01-01

    Twenty-five children (mean age, 8 years) with spina bifida (occult in 10), who were under active consideration for surgical intervention became of clinical deterioration have been assessed with MR imaging. T1-weighted spin-echo (SE) images (500/17 [repetition time msec/echo time msec]) were obtained in at least two planes. T2-weighted SE sequences were reserved for further tissue characterization. Anomalies detected requiring surgical review included diastematomyelia (n = 6), tethered cord (n = 10), hydromyelia (n = 4), and cord cyst (n = 1). Eight were not considered for surgery (cord atrophy and small hydromyelias). Diastem spurs were best identified on CT. MR imaging provided accurate preoperative assessment (11 of 13 cases) and will replace invasive tests, which should now be reserved for those cases where MR imaging does not elucidate the clinical signs

  14. [Orthopedic management of spina bifida].

    Science.gov (United States)

    Biedermann, R

    2014-07-01

    Spina bifida is associated with congenital deformities, such as kyphosis, spinal malformations, teratological hip dislocations, clubfeet, vertical talus and also with acquired deformities due to muscle imbalance and impaired biomechanics. The degree of the acquired deformities and the mobility of the patient depend on the level of the spinal lesion. Neurological symptoms are mostly asymmetric and there is an inconsistent correlation between the anatomical level of the lesion and muscle function. Deficits of sensation are usually one to two levels lower than the motor level. An exact neurological diagnosis should not be made before the second or third year of life and an early prognosis about walking ability should be avoided. The level L3 and therefore function of the quadriceps is a functional milestone after which modified independent ambulation with the use of ankle foot orthoses (AFO) and crutches is possible. The basic principle is to support verticalization and gait even when loss of ambulation is later expected. It is also important to support and maintain sitting ability for high lesions, if necessary with correction of the spinal deformity. Findings in gait analysis have shifted the focus of treatment from radiological criteria to functional improvement, thus maintenance of the flexibility of the hip is the main goal of hip surgery. Reduction of the hip often leads to stiffness and has a high redislocation rate. Clubfoot deformities should be treated early and foot arthrodesis and stiffness have to be avoided. Another focus is the prevention of joint contracture by early prophylactic treatment. The purpose of management is to maximize the functional potential of the child. Subjective well-being, absence of pain, mobility and socialization are the main goals. This does not necessarily imply ambulation; nevertheless, verticalization and associated orthotic management is one major objective of the orthopedic management of spina bifida.

  15. Obesity Prevention for Individuals with Spina Bifida.

    Science.gov (United States)

    Polfuss, Michele; Bandini, Linda G; Sawin, Kathleen J

    2017-06-01

    Obesity is a common comorbidity in individuals with spina bifida. Carrying excess weight exacerbates the inherent health challenges associated with spina bifida, impedes the individual's ability to self-manage their condition, and creates further challenges for family members and caregivers. This manuscript provides a narrative review of key issues for understanding and prevention of obesity in persons with spina bifida within the context of the social ecological model. Specific variables related to obesity and spina bifida include individual factors (i.e., body composition and measurement issues, energy needs, eating patterns, physical activity, and sedentary activity) family factors (i.e., parenting/family, peers), community factors (i.e., culture, built environment, healthcare and healthcare providers, and school), and societal factors (i.e., policy issues). Due to the complex etiology of obesity and its increased prevalence in individuals with spina bifida, it is critical to initiate prevention efforts early with a multifactorial approach for this at-risk population. Increased research is warranted to support these efforts.

  16. Executive functions in adolescents with spina bifida: relations with autonomy development and parental intrusiveness.

    Science.gov (United States)

    Tuminello, Elizabeth R; Holmbeck, Grayson N; Olson, Rick

    2012-01-01

    The current study was part of a larger longitudinal investigation and examined the relation of parent-report and performance measures of executive functioning (EF) with measures of behavioral and emotional autonomy and parental intrusiveness in adolescents with and without spina bifida (SB; n=65 in a comparison sample and 61 in an SB sample; M age=14.55, SD=0.63). For both groups, higher levels of parent-reported EF problems predicted higher levels of observed child dependency and lower levels of teacher-reported intrinsic motivation. Higher scores on performance EF measures predicted lower levels of observed child dependency and observed maternal intrusiveness for both groups. In adolescents with SB only, higher performance EF scores predicted higher intrinsic motivation and emotional autonomy from both mother and father and predicted lower levels of observed paternal intrusiveness. While causal conclusions cannot be drawn, EFs appear to be closely related to autonomy development and parental intrusiveness, particularly for adolescents with SB. These results suggest that the inclusion of EF training in interventions targeting adolescents with SB may be beneficial for autonomy development.

  17. Discrepancies in mother and child perceptions of spina bifida medical responsibilities during the transition to adolescence: associations with family conflict and medical adherence.

    Science.gov (United States)

    Psihogios, Alexandra M; Holmbeck, Grayson N

    2013-09-01

    This study investigated mother-child discrepancies over perceptions of who is responsible for spina bifida (SB) medical tasks in relation to family conflict and medical adherence. 140 youth with SB and their mothers completed questionnaires regarding who is responsible for specific SB medical tasks, family conflict, and medical adherence. An observational measure was also used to assess family conflict. Although children viewed themselves as more responsible for medical management than mothers did, mother-child discrepancies were not associated with family conflict or medical adherence. Interaction effects revealed that adherence was better when family conflict was low and when parents were responsible for medical tasks. Parental involvement in SB medical care is essential for optimal medical adherence during adolescence. The presence of family conflict also plays an influential role on SB medical adherence. Future research should evaluate the relations between discrepancies, family conflict, and medical adherence across time.

  18. Youth and young adults with spina bifida: their utilization of physician and hospital services.

    Science.gov (United States)

    Young, Nancy L; Anselmo, Lianne A; Burke, Tricia A; McCormick, Anna; Mukherjee, Shubhra

    2014-03-01

    To describe current patterns of health care utilization of youth and young adults who have spina bifida (SB) and provide evidence to guide the development of health care for this growing population. We conducted a secondary analysis of health services utilization data from the Canadian Institute for Health Information to determine the rates and patterns of health care utilization, because comprehensive health care has been recognized as critical to positive health outcomes. Participants were identified from 6 publicly funded children's treatment centers. Health records from youth (n=164; age range, 13.0-17.9y) and adults (n=120; age range, 23.0-32.9y) with SB contributed to this study. Not applicable. The rates of outpatient physician visits and hospital admissions for the youth and adult groups were calculated. The proportion with a "medical home" was also calculated. The annual rates of outpatient physician visits per 1000 persons were 8031 for youth and 8524 for adults with SB. These rates were approximately 2.9 and 2.2 times higher, respectively, than for their age-matched peers. On average, 12% of youth and 24% of adults with SB had a medical home. The annual rates of hospital admissions per 1000 persons were 329 for youth and 285 for adults with SB. Rates of admissions were 19.4 and 12.4 times higher, respectively, for these groups than for the general population. It appears that persons with SB are accessing health services more often than their age-matched peers, and few have a medical home. We recommend that seamless medical care be provided to all adults with SB, coordinated by a primary care provider, to facilitate comprehensive care. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... Opportunities Grants Process, Policies & Strategies Peer Review Small Business Programs Training & Career ... Video: Surgery on Fetus Reduces Complications of Spina Bifida Share ...

  20. Parents' psychosocial adjustment in families of children with Spina Bifida

    NARCIS (Netherlands)

    Vermaes, Ignatius Petrus Renatus

    2007-01-01

    Spina bifida is the most common, congenital, neurological disorder. Children with spina bifida live with a range of impairments depending on the severity and the location of the spinal defect. Medical treatment of the disorder is very complex and can involve decision-making processes around

  1. Spina Bifida: General Information. Fact Sheet Number 12 = La Espina Bifida: Informacion General. Fact Sheet Number 12.

    Science.gov (United States)

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet offers definitions of the three types of spina bifida, outlines their incidence, describes characteristics of individuals with spina bifida, and reviews educational implications. The fact sheet emphasizes that school programs should be flexible to accommodate these students' special needs and frequent absences, that children with…

  2. Resilience, self-esteem and self-compassion in adults with spina bifida.

    Science.gov (United States)

    Hayter, M R; Dorstyn, D S

    2014-02-01

    Cross-sectional survey. To examine factors that may enhance and promote resilience in adults with spina bifida. Community-based disability organisations within Australia. Ninety-seven adults with a diagnosis of spina bifida (SB) completed a survey comprising of demographic questions in addition to standardised self-report measures of physical functioning (Craig Handicap Assessment and Reporting Technique), resilience (Connor-Davidson Resilience Scale, 10 item), self-esteem (Rosenberg Self-esteem Scale), self-compassion (Self-compassion Scale) and psychological distress (Depression Anxiety Stress Scales, 21 item). The majority (66%) of respondents reported moderate to high resilience. Physical disability impacted on coping, with greater CD-RISC 10 scores reported by individuals who were functionally independent in addition to those who experienced less medical co-morbidities. Significant correlations between resilience and psychological traits (self-esteem r=0.36, Pself-esteem and self-compassion. It follows that cognitive behavioural strategies with a focus on self-management may, in part, contribute to the process of resilience in this group. Further large-scale and longitudinal research will help to confirm these findings.

  3. Social Skills in Youth With Spina Bifida: A Longitudinal Multimethod Investigation Comparing Biopsychosocial Predictors.

    Science.gov (United States)

    Holbein, Christina E; Peugh, James L; Holmbeck, Grayson N

    2017-11-01

    To examine the relative contributions of neuropsychological (attention and executive function), family (cohesion and conflict), and health (body mass index, lesion level, gross motor function) domains on social skills over time in youth with spina bifida (SB). In all, 140 youth with SB (T1 mean age = 11.43 years) and their families participated in the study at baseline with an additional visit 2 years later. Study variables were assessed with multiple methods (questionnaire, medical chart review, observation, neuropsychological tests) and reporters (parents, teachers). Multivariate hierarchical linear regressions determined the predictive power of the three domains for T2 social skills. Neuropsychological variables accounted for significant variance in mother- and father-reported T2 social skills. Neither family nor health variables contributed significantly to later social skills when other domains were included in the model. Neuropsychological factors are particularly important for social skill development in youth with SB. Findings can inform screening and intervention practices. © The Author 2017. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  4. Spina Bifida: Pathogenesis, Mechanisms, and Genes in Mice and Humans

    Directory of Open Access Journals (Sweden)

    Siti W. Mohd-Zin

    2017-01-01

    Full Text Available Spina bifida is among the phenotypes of the larger condition known as neural tube defects (NTDs. It is the most common central nervous system malformation compatible with life and the second leading cause of birth defects after congenital heart defects. In this review paper, we define spina bifida and discuss the phenotypes seen in humans as described by both surgeons and embryologists in order to compare and ultimately contrast it to the leading animal model, the mouse. Our understanding of spina bifida is currently limited to the observations we make in mouse models, which reflect complete or targeted knockouts of genes, which perturb the whole gene(s without taking into account the issue of haploinsufficiency, which is most prominent in the human spina bifida condition. We thus conclude that the need to study spina bifida in all its forms, both aperta and occulta, is more indicative of the spina bifida in surviving humans and that the measure of deterioration arising from caudal neural tube defects, more commonly known as spina bifida, must be determined by the level of the lesion both in mouse and in man.

  5. Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Atta, Callie A M; Fiest, Kirsten M; Frolkis, Alexandra D; Jette, Nathalie; Pringsheim, Tamara; St Germaine-Smith, Christine; Rajapakse, Thilinie; Kaplan, Gilaad G; Metcalfe, Amy

    2016-01-01

    Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region's food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation. We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population. An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts. Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as "mandatory" or "voluntary" folic acid fortification according to each country's folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food

  6. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... is no longer being updated. Video: Surgery on Fetus Reduces Complications of Spina Bifida Wednesday, March 9, ... Institutes of Health and four research institutions. The fetal surgical procedure also increases the chances that a ...

  7. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... This page is no longer being updated. Video: Surgery on Fetus Reduces Complications of Spina Bifida Wednesday, ... the NICHD, describes the study’s findings. Read the Management of Myelomeningocele Study (MOMS) Interview text alternative . The ...

  8. Are There Disorders or Conditions Associated with Spina Bifida?

    Science.gov (United States)

    ... additional physical and psychological conditions, including digestive, vision, sexual, social, and emotional problems; obesity; and depression. Centers for Disease Control and Prevention. (2011). Spina bifida: Health issues and treatments. Retrieved March 30, 2012, from http://www.cdc. ...

  9. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... Scientific Director (OSD) Affinity Groups & Labs (AG&L) Scientists Emeriti National Center for Medical Rehabilitation Research (NCMRR) ... of Spina Bifida Wednesday, March 9, 2011 Recently, scientists in an NIH study reported that a surgical ...

  10. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... OLPP) Office of Science Policy, Reporting, and Program Analysis (OSPRA) Division of Extramural Research (DER) Extramural Scientific ... Fetus Reduces Complications of Spina Bifida Share Facebook Twitter Pinterest Email Print NICHD Archive Note: Information on ...

  11. Surgery on Fetus Reduces Complications of Spina Bifida

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  12. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... Institutes of Health Directory Follow follow us on Facebook follow us on Twitter follow us on Pinterest ... on Fetus Reduces Complications of Spina Bifida Share Facebook Twitter Pinterest Email Print NICHD Archive Note: Information ...

  13. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... bifida, a condition in which the spinal column fails to close around the spinal cord. With myelomeningocele, ... gov/ . The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers ...

  14. Mental health and parenting characteristics of caregivers of children with spina bifida.

    Science.gov (United States)

    Malm-Buatsi, Elizabeth; Aston, Christopher E; Ryan, Jamie; Tao, Yeun; Palmer, Blake W; Kropp, Bradley P; Klein, Jake; Wisniewski, Amy B; Frimberger, Dominic

    2015-04-01

    Within the chronic medical illness literature, associations exist between caring for an affected child and parent mental health. The few studies examining both mothers and fathers provide mixed results. The purpose of this study is to examine associations between caregiver anxiety, depression, and parenting variables in caregivers of youth with SB as these relate to marital status, age, education, household income, work status, and child's severity of SB. The aim of this study is to examine associations between anxiety, depression, and parenting variables in caregivers of youth with spina bifida and how they relate to demographic and disease variables. Exploratory analyses examined the relationship between participation in support activities and depressive and anxious symptomatology and parenting characteristics. Eighty-four primary caregivers (49 mothers) of 51 youth with spina bifida completed measures of depressive and anxious symptomology, parenting stress, parent overprotection, and perceived child vulnerability. There were differences between mothers and fathers on several parenting characteristics; however, these were related more to marital status and employment than to gender of the caretaker per se. In the 33 married/remarried couples for whom both spouses participated, stress for the mothers was correlated with stress for the fathers. This correlation was strongest in the 12 married couples in which the mother works. Higher perceived vulnerability scores were reported in parents of SB patients in the younger age group, especially preschoolers (0-4 years). Parents of children with shunts reported more anxiety, depression and perceived child vulnerability. Both male and female caregivers of younger children reported significantly higher protectiveness scores. Involvement in recreational activities with other families affected by SB was associated with more positive parenting characteristics for mothers. Stress and protectiveness were found to be positively

  15. Memory and selective learning in children with spina bifida-myelomeningocele and shunted hydrocephalus: A preliminary study

    Directory of Open Access Journals (Sweden)

    Vachha Behroze

    2005-11-01

    Full Text Available Abstract Background Selective learning is the ability to select items of relevance from among less important items. Limited evidence exists regarding the efficiency with which children with spina bifida-myelomeningocele and shunted hydrocephalus (SB/SH are able to learn information. This report describes initial data related to components of learning and metacognitive skills in children with SB/SH. Methods Twenty six children with SB/SH and 26 controls (age: 7 – 16 y with average intelligence, and monolingual English-speaking backgrounds participated in the study. Exclusion criteria for the SB/SH group were: prior history of shunt infection, history of seizure or shunt malfunction within the previous three months, prior diagnoses of attention disorders and/or clinical depression. Children were presented lists of words with equal exemplars each of two distinct semantic categories (e.g. fruits, animals, and told to make as high a score as possible by learning the words. The value of the words was designated by category membership (e.g. animals = low value; fruits = high value. The total number of words learned across three learning trials was used to determine memory span. Selective learning efficiency (SLE was computed as the efficiency with which items of greater value were selectively learned across three trials. Results Children with SB/SH did worse than controls on memory span (P Conclusion Success in school is often dependent on the ability to recall important facts selectively and ignore less important information. Children with SB/SH in our study had a poor memory span and were unable to monitor and report an efficient and workable metacognitive strategy required to remember a list of words. Preliminary findings may begin to explain our previous clinical and research findings wherein children with SB/SH often focus on extraneous details, but demonstrate difficulty remembering the main gist of a story/event.

  16. Variation in definitions of urinary tract infections in spina bifida patients: a systematic review.

    Science.gov (United States)

    Madden-Fuentes, Ramiro Jose; McNamara, Erin Rebekah; Lloyd, Jessica Catherine; Wiener, John Samuel; Routh, Jonathan Charles; Seed, Patrick Casey; Ross, Sherry Sedberry

    2013-07-01

    Urinary tract infections (UTIs) are a common source of morbidity among children with spina bifida (SB) and are a frequently reported outcome in studies of this patient population. However, the criteria for a diagnosis of UTI are often not stated. We evaluated the literature on SB patients for the criteria that authors use to define parameters in reporting UTI outcomes. Embase and Medline were queried with the medical subject heading terms “spinal dysraphism,” “myelomeningocele,” “infection,”and “urinary tract infection.” A second search with the exploded term“spina bifida” and “urinary tract infection” was performed. Original research studies reporting a UTI outcome in SB patients were included and evaluated by 2 independent reviewers for the presence of a UTI definition and diagnostic criteria. We identified 872 publications, of which 124 met inclusion criteria. Forty-five of 124 (36.3%) studies reporting UTI as an outcome provided a definition of UTI. Of 124 studies, 28 (22.6%) were published in pediatric journals and 69 (55.6%) in urology journals. A definition of UTI was provided in 11 (39.3%) and 26 (37.7%) studies, respectively. “Fever,culture, and symptoms” defined a UTI in 17 of 45 studies. Journal category and presence of UTI definitions did not correlate (P = .71). Explicit definitions for UTI are heterogeneous and infrequently applied in studies of SB patients, limiting study reliability and estimates of true UTI rates in this population. Future studies will benefit from the development and application of a standard definition for UTI in this population.

  17. Arnold-Chiari-II malformation and cognitive functioning in spina bifida.

    NARCIS (Netherlands)

    Vinck, A.; Maassen, B.A.M.; Mullaart, R.A.; Rotteveel, J.J.

    2006-01-01

    Spina bifida is a multifaceted neurological condition with complex neuropsychological sequelae. The cognitive outcome in spina bifida has frequently been attributed to the severity of the hydrocephalus. However, because of complex neuropathology, the influence of hydrocephalus alone does not

  18. Oral health status of a sample of Venezuelan patients with spina bifida. A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Mariana Morales-Chávez

    2016-09-01

    Full Text Available Spina bifida (SB is a congenital malformation of the spinal cord associated with several vertebral abnormalities caused by incomplete neural tube closure. The aim of this study is to report on the oral health status of a sample of Venezuelan patients with SB. Materials and Methods: An observational cross-sectional study was performed in 30 patients with SB to determine their oral health status and other variables of interest. Results: A 46.7% of the patients had a history of caries: 22% in the 1-4 year group, 71.4% in the 5-7 year group, and 100% in the 8-16 year group. The dmft and DMFT indices were 1.55 and 3.50, respectively. A 46.7% of the patients had gingivitis, 30% had dental calculus, with an OHI-S of 2. The 83% had Angle Class II and 17%, Angle Class I. A 40% had parafunctional habits such as digital suction, use of pacifiers and onicophagia. The 70% had deep palate. Conclusion: Patients with SB have specific oral characteristics and risk factors that must be taken into account in dental treatments to provide adequate care and improve their quality of life

  19. Differences between the events preceding spina bifida and anencephaly.

    Science.gov (United States)

    James, W H

    1981-02-01

    It is usually held that there is a time continuum in the formation of monoxygotic (MZ) twins which is indexed by their placentation, running from dichorionic to monochorionic diamniotic to monochorionic monoamniotic and conjoined pairs. There is good evidence that this continuum is characterised by a continuum of predisposition to anencephaly, slightly raised in dichorionic pairs but very high in some sorts of conjoined pairs. Although MZ twins, especially monoamniotic and conjoined pairs, are peculiarly liable to anencephaly, they are not particularly susceptible to spina bifida. Among twin pairs concordant for anencephaly or spina bifida, there are strikingly few concordant in the sense of one twin having anencephaly and the other spina bifida, in contrast with the numbers of pairs concordant for the same malformation. The prevalence of anencephaly in double monsters varies with the type of monster, being high in diprosopus. These findings may be explained by the timing of embryonic events.

  20. Paraoxonase 1 polymorphisms and haplotypes and the risk for having offspring affected with spina bifida in Southeast Mexico.

    Science.gov (United States)

    Gonzalez-Herrera, Lizbeth; Martín Cerda-Flores, Ricardo; Luna-Rivero, Marianne; Canto-Herrera, Jorge; Pinto-Escalante, Doris; Perez-Herrera, Norma; Quintanilla-Vega, Betzabet

    2010-11-01

    Spina bifida (SB) is a common congenital malformation in Southeast Mexico. Parents of children with SB reside in areas with frequent pesticide spraying or have agriculture activities, suggesting potential exposure to pesticides. Paraoxonase 1 (PON1) is the responsible enzyme for deactivation of organophosphates (OP) in the central nervous system. Polymorphisms of PON1 genes influence the catalytic activity and plasma protein level of the enzyme, therefore, genotypic characterization of PON1 gene represents a potential predictor for susceptibility to OP-related effects. The frequency of PON1 haplotypes and polymorphisms (-108CT, L55M, and Q192R) were determined in this study. A case-control study was performed to evaluate the risk for having offspring affected by SB in 152 cases and 160 control parents. Polymorphisms were determined by PCR amplification and restriction fragment length polymorphism and Real Time-PCR. Odds ratios and confidence interval 95% were estimated. Genotype frequencies for the three PON1 polymorphisms were distributed according to Hardy-Weinberg expectations (p > 0.05) and were significantly different between cases and controls (p Mexico. © 2010 Wiley-Liss, Inc.

  1. Cebocephaly, alobar holoprosencephaly, spina bifida, and sirenomelia in a stillbirth.

    Science.gov (United States)

    Chen, C P; Shih, S L; Liu, F F; Jan, S W

    1997-01-01

    Cebocephaly and sirenomelia are uncommon birth defects. Their association is extremely rare; however, the presence of spina bifida with both conditions is not unexpected. We report on a female still-birth with cebocephaly, alobar holoprosencephaly, cleft palate, lumbar spina bifida, sirenomelia, a single umbilical artery, and a 46,XX karyotype, but without maternal diabetes mellitus. Our case adds to the examples of overlapping cephalic and caudal defects, possibly related to vulnerability of the midline developmental field or axial mesodermal dysplasia spectrum. Images PMID:9132501

  2. Observed Macro- and Micro-Level Parenting Behaviors During Preadolescent Family Interactions as Predictors of Adjustment in Emerging Adults With and Without Spina Bifida

    Science.gov (United States)

    Amaro, Christina M.; Devine, Katie A.; Psihogios, Alexandra M.; Murphy, Lexa K.; Holmbeck, Grayson N.

    2015-01-01

    Objective To examine observed autonomy-promoting and -inhibiting parenting behaviors during preadolescence as predictors of adjustment outcomes in emerging adults with and without spina bifida (SB). Methods Demographic and videotaped interaction data were collected from families with 8/9-year-old children with SB (n = 68) and a matched group of typically developing youth (n = 68). Observed interaction data were coded with macro- and micro-coding schemes. Measures of emerging adulthood adjustment were collected 10 years later (ages 18/19 years; n = 50 and n = 60 for SB and comparison groups, respectively). Results Autonomy-promoting (behavioral control, autonomy-relatedness) and -inhibiting (psychological control) observed preadolescent parenting behaviors prospectively predicted emerging adulthood adjustment, particularly within educational, social, and emotional domains. Interestingly, high parent undermining of relatedness predicted better educational and social adjustment in the SB sample. Conclusions Parenting behaviors related to autonomy have long-term consequences for adjustment in emerging adults with and without SB. PMID:24864277

  3. Surgery on Fetus Reduces Complications of Spina Bifida

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    Full Text Available ... Fetus Reduces Complications of Spina Bifida Wednesday, March 9, 2011 Recently, scientists in an NIH study reported ... Owner Office of Communications Last Reviewed Date 3/9/2011 Contact Us Publications Sitemap Español facebook twitter ...

  4. Correlates of Self Esteem in Adolescents with Spina Bifida.

    Science.gov (United States)

    Eckart, M. L.

    The study examined correlates of self-esteem in 54 adolescents and young adults (ages 12-22) with spina bifida. Core issues identified were the relationships of global self-esteem and perceived competencies in specific areas, perceptions of control, and identification with the physically handicapped. Relationships of self-esteem to age, gender,…

  5. Pregnancy outcome and complications in women with spina bifida.

    Science.gov (United States)

    Arata, M; Grover, S; Dunne, K; Bryan, D

    2000-09-01

    To describe the antenatal complications, mode of delivery and outcome of pregnancy in women with spina bifida. Case series of women known to have attended the spina bifida clinic at the Royal Children's Hospital. Medical records, postal questionnaire and telephone interview were utilized to collect data on the effect of pregnancy on the health of women and the effect of spina bifida on pregnancy outcome. Of 207 women born between 1945 and 1975, 23 reported having a pregnancy, and 17 who had completed pregnancies agreed to participate. The 17 women had a total of 29 pregnancies, with 23 pregnancies progressing to births. Fourteen of 17 women had antenatal admissions, with wheelchair-dependent women requiring more-frequent and longer admissions. Recurrent urinary infections in pregnancy occurred in women with a prior history of urinary infections; stomal problems occurred but were not serious; mobility was reduced for two women during pregnancy, with full recovery afterwards; and preexisting pressure sores worsened during pregnancy. Vaginal deliveries occurred in one in five pregnancies of women who were wheelchair dependent and in ten of eighteen pregnancies in independently mobile women, including seven of eight pregnancies of independently mobile women without ileal conduits. Cesarean sections were accompanied by postoperative complications in 10 women. Women with spina bifida who become pregnant generally have a positive outcome, with relatively low complication rates.

  6. The spectrum of urological disease in patients with spina bifida.

    LENUS (Irish Health Repository)

    Cahill, R A

    2012-02-03

    BACKGROUND: [corrected] Urological complications are the major cause of ill health during childhood and adult life of patients with spina bifida but the significance of urinary tract disease on the individual and the healthcare services is underemphasised. AIM: To assess the effects of spina bifida on the individual and the healthcare services. METHODS: A retrospective review was performed to assess the frequency and significance of urological conditions requiring hospital attendance in patients with spina bifida currently attending a specialised multidisciplinary clinic over a period of six months. RESULTS: Urinary sepsis accounted for the majority of admissions (62%), while 38 of 62 patients required 60 surgical procedures. Targeting the primary urological abnormality (the dysfunctional and usually poorly compliant bladder) allows implementation of effective treatments, including regular intermittent bladder catherisation (52%) in order to preserve upper renal tract function. Associated postural abnormalities complicated both conservative and interventional therapies. CONCLUSION: This study highlights the surgical commitment for units caring for patients with spina bifida, the important considerations for the future healthcare services, and the range and severity of urological diseases encountered by these patients.

  7. Neonatal loss of motor function in human spina bifida aperta

    NARCIS (Netherlands)

    Sival, Deborah A; van Weerden, Tiemen W; Vles, Johan S H; Timmer, Albertus; den Dunnen, Wilfred F A; Staal-Schreinemachers, A L; Hoving, Eelco W.; Sollie, Krystyne M; Kranen-Mastenbroek, Vivianne J M; Sauer, Pieter J J; Brouwer, Oebele F

    OBJECTIVE: In neonates with spina bifida aperta (SBA), leg movements innervated by spinal segments located caudal to the meningomyelocele are transiently present. This study in neonates with SBA aimed to determine whether the presence of leg movements indicates functional integrity of neuronal

  8. Spina bifida: A multidisciplinary perspective on a many-faceted ...

    African Journals Online (AJOL)

    Open spina bifida or myelomeningocele (SBM) is the most common birth defect involving the central nervous system, second only in incidence to congenital cardiac disease. Although recognised since antiquity, with anthropological relics depicting affected individuals and suggestive descriptions in the writings of ...

  9. Yield of 117Sb, 118mSb, 120mSb, 122Sb, 124Sb in reactions Sn (p, xn)

    International Nuclear Information System (INIS)

    Dmitriev, P.P.; Konstantinov, I.O.

    1993-01-01

    Yield of 117 Sb, 118m Sb, 120m Sb, 122 Sb, 124 Sb from thick target depending on proton energy is measured. The maximum proton energy is 21.7±0.2 MeV. Antimony isotopes yield in separate reactions when irradiating of tin isotopes with 100% enrichment is determined using the method published earlier. The methods for production of 117 Sb, 118m Sb, 120m Sb, 122 Sb, 124 Sb with high radioisotope purity are shown. 13 refs., 1 fig., 3 tabs

  10. Central Somatosensory Networks Respond to a De Novo Innervated Penis: A Proof of Concept in Three Spina Bifida Patients.

    Science.gov (United States)

    Kortekaas, Rudie; Nanetti, Luca; Overgoor, Max L E; de Jong, Bauke M; Georgiadis, Janniko R

    2015-09-01

    Spina bifida (SB) causes low spinal lesions, and patients often have absent genital sensation and a highly impaired sex life. TOMAX (TO MAX-imize sensation, sexuality and quality of life) is a surgical procedure whereby the penis is newly innervated using a sensory nerve originally targeting the inguinal area. Most TOMAX-treated SB patients initially experience penile stimulation as inguinal sensation, but eventually, the perception shifts to penis sensation with erotic feelings. The brain mechanisms mediating this perceptual shift, which are completely unknown, could hold relevance for understanding the brain's role in sexual development. The aim of this study was to study how a newly perceived penis would be mapped onto the brain after a lifelong disconnection. Three TOMAX-treated SB patients participated in a functional magnetic resonance imagery experiment while glans penis, inguinal area, and index finger were stimulated with a paint brush. Brush stimulation-induced activation of the primary somatosensory cortex (SI) and functional connectivity between SI and remote cerebral regions. Stimulation of the re-innervated side of the glans penis and the intact contralateral inguinal area activated a very similar location on SI. Yet, connectivity analysis identified distinct SI functional networks. In all three subjects, the middle cingulate cortex (MCC) and the parietal operculum-insular cortex (OIC) were functionally connected to SI activity during glans penis stimulation, but not to SI activity induced by inguinal stimulation. Investigating central somatosensory network activity to a de novo innervated penis in SB patients is feasible and informative. The consistent involvement of MCC and OIC above and beyond the brain network expected on the basis of inguinal stimulation suggests that these areas mediate the novel penis sensation in these patients. The potential role of MCC and OIC in this process is discussed, along with recommendations for further research.

  11. MR imaging of the spine in children with spina bifida

    International Nuclear Information System (INIS)

    Williamson, M.R.; Glasier, C.M.; Angtuaco, E.J.C.; McConnell, J.R.; Chadduck, W.M.; Binet, E.F.

    1986-01-01

    Twenty infants and children with spina bifida were examined as outpatients with spinal MR imaging. Studies were performed using a 0.6-T imager and a surface coil. These examinations were performed in patients previously operated on who had progressive neurologic symptoms and in newly diagnosed patients to exclude lipomyeloschisis, low-lying cord, diastematomyelia, or syringomyelia. Predominantly T1-weighted sequences were obtained in at least two orthogonal planes with a 5-mm section thickness. Eighteen patients had a low-lying spinal cord. Six patients had syringomyelia, usually lumbar. Five patients had intraspinal lipomas, and three had diastematomyelia. MR imaging was diagnostic in 17 instances. Patient motion or severe kyphoscoliosis comprised three examinations. MR imaging is the screening examination of choice in children with spina bifida

  12. Reproductive Health Care for Women with Spina Bifida

    Directory of Open Access Journals (Sweden)

    Amie B. Jackson

    2007-01-01

    Full Text Available Women with spina bifida have unique health care concerns and as the life expectancy of this population increases, they are transitioning from adolescence to womanhood and entering their reproductive years with little information about what to expect. Likewise, their health care providers do not have the benefit of evidence-based research that comprehensively addresses the issues these women may face related to reproduction or aging. Few studies have focused on the effects that spina bifida may have on these women's reproductive systems, nor has attention been paid to the effects that possible reproductive endocrine changes may have on their disability. Needless to say, concerns about sexuality, sexual function, and pregnancy are just as important to these women as they are to their able-bodied counterparts.

  13. Models of Self in Families of People with Spina Bifida

    Directory of Open Access Journals (Sweden)

    Viviam Rafaela Barbosa Pinheiro Freire

    Full Text Available Abstract: Models of self reveal cultural views regarding the competences that children should acquire, and these views tend to be shared by people within the same environment. Thus, this study aims to evaluate the models of self in families of people with spina bifida. Seventeen caregivers answered an online questionnaire containing socio-demographic questions and three scales of self: autonomous, related and autonomous-related. The data were analyzed using descriptive statistics and techniques of multivariate analysis. The main results indicate that the most valued model of self was the autonomous-related model, reflecting the desire that children develop autonomy as well as interpersonal relationships. Such a model, however, is distinct from that of family groups of people with typical development living in the same cultural environment, indicating the need for families of people with spina bifida to receive support to reach their developmental goals.

  14. Cognitive Abilities of Pre- and Primary School Children with Spina Bifida in Uganda

    Science.gov (United States)

    Bannink, Femke; Fontaine, Johnny R. J.; Idro, Richard; van Hove, Geert

    2016-01-01

    This study investigates cognitive abilities of pre/primary school children without and with spina bifida in Uganda. Qualitative semi structured interviews and quantitative functioning scales measurements were combined and conducted with 133 parents, 133 children with spina bifida, and 35 siblings. ANCOVA was used to test for differences in…

  15. Milestone achievement in emerging adulthood in spina bifida: a longitudinal investigation of parental expectations

    Science.gov (United States)

    Holbein, Christina E; Zebracki, Kathy; Bechtel, Colleen F; Papadakis, Jaclyn Lennon; Bruno, Elizabeth Franks; Holmbeck, Grayson N

    2016-01-01

    Aim To assess changes over time in parents' expectations of adult milestone achievement (college attendance, full-time job attainment, independent living, marriage, parenthood) for young people with spina bifida, to examine how expectancies relate to actual milestone achievement, and to compare milestone achievement in emerging adults with spina bifida with that of peers with typical development. Method Sixty-eight families of children with spina bifida (mean=8.34y, 37 male, 31 female) and 68 families of children with typical development (mean=8.49y, 37 male, 31 female) participated at Time 1. At all subsequent timepoints, parents of young people with spina bifida were asked to rate their expectations of emerging adulthood milestone achievement. At Time 7, when participants were 22 to 23 years old, milestone achievement was assessed. Results Parents of young people with spina bifida lowered their expectations over time for most milestones; parents of children with higher cognitive ability reported decreases of lower magnitude. Parent expectancies were optimistic and unrelated to actual milestone achievement. Emerging adults with spina bifida were less likely than individuals with typical development to achieve all milestones. Interpretation Optimistic parental expectations may be adaptive for children with spina bifida and their families, although it is important for families to set realistic goals. Healthcare providers serve a key role in helping families of young people with spina bifida prepare for emerging adulthood. PMID:27651215

  16. Urological care for children with spina bifida : Individual, tailored and without antibiotic prophylaxis

    NARCIS (Netherlands)

    Zegers, S.H.J.

    2017-01-01

    In our SPIN UTI study, we have focused on the urological problems, urinary tract infections and Quality of Life in spina bifida children. For eighteen months, we have analyzed the diagnosing, treatment and prevention of urinary tract infections in 176 children with spina bifida from Utrecht and

  17. Marginal maternal vitamin B12 status increases the risk of offspring with spina bifida.

    NARCIS (Netherlands)

    Groenen, P.; Rooij, I.A.L.M. van; Peer, P.G.M.; Gooskens, R.H.; Zielhuis, G.A.; Steegers-Theunissen, R.P.M.

    2004-01-01

    OBJECTIVE: The purpose of this study was to investigate B vitamins and homocysteine as risk factor for offspring with spina bifida. STUDY DESIGN: Blood samples from 45 mothers and their children with spina bifida and from 83 control mothers and their children were obtained to determine the levels of

  18. Community Knowledge, Beliefs, Attitudes, and Practices towards Children with Spina Bifida and Hydrocephalus in Uganda

    Science.gov (United States)

    Bannink, Femke; Stroeken, Koenraad; Idro, Richard; van Hove, Geert

    2015-01-01

    This article describes the findings of a qualitative study on knowledge, beliefs, attitudes, and practices towards children with spina bifida and hydrocephalus in four regions of Uganda. Focus group discussions and semi-structured interviews were held with parents of children with spina bifida and hydrocephalus, policy-makers, and service…

  19. Spina Bifida Care In Kenya Through A Network Of Mobile Clinics ...

    African Journals Online (AJOL)

    Background: Children with spina bifida require ongoing multidisciplinary care in order to prevent complications and improve quality of life. Bethany Crippled Children's Centre of Kenya and BethanyKids at Kijabe Hospital have been providing such care for spina bifida patients through a network of mobile clinics throughout ...

  20. Diffusion tensor MRI and fiber tractography of the sacral plexus in children with spina bifida

    DEFF Research Database (Denmark)

    Haakma, Wieke; Dik, Pieter; ten Haken, Bennie

    2014-01-01

    anatomical and microstructural properties of the sacral plexus of patients with spina bifida using diffusion tensor imaging and fiber tractography. MATERIALS AND METHODS: Ten patients 8 to 16 years old with spina bifida underwent diffusion tensor imaging on a 3 Tesla magnetic resonance imaging system...... diffusivity values at S1-S3 were significantly lower in patients. CONCLUSIONS: To our knowledge this 3 Tesla magnetic resonance imaging study showed for the first time sacral plexus asymmetry and disorganization in 10 patients with spina bifida using diffusion tensor imaging and fiber tractography...

  1. Mood-Stabilizing Anticonvulsants, Spina Bifida, and Folate Supplementation: Commentary.

    Science.gov (United States)

    Patel, Neil; Viguera, Adele C; Baldessarini, Ross J

    2018-02-01

    High risks of neural tube defects and other teratogenic effects are associated with exposure in early pregnancy to some anticonvulsants, including in women with bipolar disorder. Based on a semistructured review of recent literature, we summarized findings pertaining to this topic. Valproate and carbamazepine are commonly used empirically (off-label) for putative long-term mood-stabilizing effects. Both anticonvulsants have high risks of teratogenic effects during pregnancy. Risks of neural tube defects (especially spina bifida) and other major malformations are especially great with valproate and can arise even before pregnancy is diagnosed. Standard supplementation of folic acid during pregnancy can reduce risk of spontaneous spina bifida, but not that associated with valproate or carbamazepine. In contrast, lamotrigine has regulatory approval for long-term use in bipolar disorder and appears not to have teratogenic effects in humans. Lack of protective effects against anticonvulsant-associated neural tube defects by folic acid supplements in anticipation of and during pregnancy is not widely recognized. This limitation and high risks of neural tube and other major teratogenic effects, especially of valproate, indicate the need for great caution in the use of valproate and carbamazepine to treat bipolar disorder in women of child-bearing age.

  2. The Infant and Young Child with Spina Bifida: Major Medical Concerns.

    Science.gov (United States)

    Shaer, Catherine M.

    1997-01-01

    This review of medical concerns in dealing with spina bifida examines neurologic and neurosurgical issues, learning issues, urological dysfunction, orthopedic issues, bowel control, latex allergy, and prenatal diagnosis and prevention. (JDD)

  3. Neuroependymal Denudation is in Progress in Full-term Human Foetal Spina Bifida Aperta

    NARCIS (Netherlands)

    Sival, Deborah A.; Guerra, Montserrat; den Dunnen, Wilfred F. A.; Batiz, Luis F.; Alvial, Genaro; Castaneyra-Perdomo, Agustin; Rodriguez, Esteban M.

    In human spina bifida aperta (SBA), cerebral pathogenesis [hydrocephalus, Sylvius aqueduct (SA) stenosis and heterotopias] is poorly understood. In animal models, loss of ventricular lining (ependymal denudation) causes SA stenosis and hydrocephalus. We aimed to investigate whether ependymal

  4. Trajectories of autonomy development across the adolescent transition in children with spina bifida.

    Science.gov (United States)

    Friedman, Deborah; Holmbeck, Grayson N; DeLucia, Christian; Jandasek, Barbara; Zebracki, Kathy

    2009-02-01

    The current study investigated individual growth in autonomy development across the adolescent transition, comparing the trajectories of children with and without spina bifida. Individual growth curve modeling procedures were utilized to describe the developmental course of autonomy across four waves of data collection, from ages 9 to 15, and to test whether illness status [spina bifida vs. matched comparison group (N = 68 for both groups at Time 1)] would significantly predict individual variability in autonomy development. Potential moderators [child gender, SES, and Peabody Picture Vocabulary Test (PPVT) score] of the association between illness status and autonomy development were also examined. Children with spina bifida demonstrated distinct developmental trajectories, though the nature of the group differences varied by type of autonomy development (emotional vs. behavioral), context (i.e. school vs. family), and reporter. Significant interactions with PPVT score and child gender were found. Overall, children with spina bifida show considerable developmental resiliency, but may lag behind their peers in specific areas of autonomy. Boys with spina bifida, and children with spina bifida who have lower than average levels of verbal intelligence, appear to be at greater risk for exhibiting delays in autonomy development.

  5. Comparison of the electrochemical performance of mesoscopic Cu2Sb, SnSb and Sn/SnSb alloy powders

    International Nuclear Information System (INIS)

    Zhang Ge; Huang Kelong; Liu Suqin; Zhang Wei; Gong Benli

    2006-01-01

    Cu 2 Sb, SnSb and Sn/SnSb mesoscopic alloy powders were prepared by chemical reduction, respectively. The crystal structures and particle morphology of Cu 2 Sb, SnSb and Sn/SnSb were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The electrochemical performances of the Cu 2 Sb, SnSb and Sn/SnSb electrodes were investigated by galvanostatic charge and discharge cycling and electrochemical impedance spectroscopy (EIS). The results showed the first charge and discharge capacities of SnSb and Sn/SnSb were higher than Cu 2 Sb, but after 15 cycles, the charge capacity fading rates of Cu 2 Sb, Sn/SnSb and Sn/SnSb were 26.16%, 55.33% and 47.39%, respectively. Cu 2 Sb had a better cycle performance, and Sn/SnSb multiphase alloy was prior to pure SnSb due to the existence of excessive Sn in Sn/SnSb system

  6. The Prevalence and Distribution of Spina Bifida in a Single Major Referral Center in Malaysia

    Directory of Open Access Journals (Sweden)

    Adibah Sahmat

    2017-11-01

    Full Text Available BackgroundThe aim of this study is to review the medical history of patients with spina bifida, encompassing both aperta and occulta types born between the years 2003 until 2016, spanning a 13-year time period. We assessed each patient and maternal parent information, details of the defects, and conditions associated with the primary defect. We also include information on patients’ ambulation and education level (where available.MethodsData from the Department of Patient Information University of Malaya Medical Centre (UMMC, Malaysia was captured from spina bifida patients (ICD10: Q05 spina bifida. Data involved patients referred to UMMC between 2003 and 2016 and/or born in UMMC within that particular time frame. We filtered and extracted the information according to the data of clinical examination, medical review, and social history provided in the medical records.ResultsA total of 86 patient records with spina bifida were analyzed. Spina bifida prevalence rate in this study ranged from 1.87 to 8.9 per 1,000 live births depending on weightage. We note that ethnicity was a factor whereby the highest numbers of spina bifida were from Malays (n = 36, 41.86%, followed by equal numbers of Chinese and Indians (n = 24, 27.91%. The highest number of diagnoses reported was myelomeningocele type-spina bifida (n = 39, 45.35%. The most common site of the spina bifida lesion was located at the lumbar region irrespective of aperta or occulta types (n = 23, 26.74%. Data on other associated phenotypes of spina bifida such as hydrocephalus and encephalocele was also captured at 37.21% (n = 32 and 1.16% (n = 1, respectively. In terms of mobility, 32.84% (n = 22/67 of patients between the ages 4 and 16 years old were found to be mobile. As many as 36.07% of patients ranging from 5 to 16 years of age (n = 22/61 received formal education ranging from preschool to secondary school.ConclusionThe prevalence of spina bifida in

  7. The Prevalence and Distribution of Spina Bifida in a Single Major Referral Center in Malaysia.

    Science.gov (United States)

    Sahmat, Adibah; Gunasekaran, Renuka; Mohd-Zin, Siti W; Balachandran, Lohis; Thong, Meow-Keong; Engkasan, Julia P; Ganesan, Dharmendra; Omar, Zaliha; Azizi, Abu Bakar; Ahmad-Annuar, Azlina; Abdul-Aziz, Noraishah M

    2017-01-01

    The aim of this study is to review the medical history of patients with spina bifida, encompassing both aperta and occulta types born between the years 2003 until 2016, spanning a 13-year time period. We assessed each patient and maternal parent information, details of the defects, and conditions associated with the primary defect. We also include information on patients' ambulation and education level (where available). Data from the Department of Patient Information University of Malaya Medical Centre (UMMC), Malaysia was captured from spina bifida patients (ICD10: Q05 spina bifida). Data involved patients referred to UMMC between 2003 and 2016 and/or born in UMMC within that particular time frame. We filtered and extracted the information according to the data of clinical examination, medical review, and social history provided in the medical records. A total of 86 patient records with spina bifida were analyzed. Spina bifida prevalence rate in this study ranged from 1.87 to 8.9 per 1,000 live births depending on weightage. We note that ethnicity was a factor whereby the highest numbers of spina bifida were from Malays ( n  = 36, 41.86%), followed by equal numbers of Chinese and Indians ( n  = 24, 27.91%). The highest number of diagnoses reported was myelomeningocele type-spina bifida ( n  = 39, 45.35%). The most common site of the spina bifida lesion was located at the lumbar region irrespective of aperta or occulta types ( n  = 23, 26.74%). Data on other associated phenotypes of spina bifida such as hydrocephalus and encephalocele was also captured at 37.21% ( n  = 32) and 1.16% ( n  = 1), respectively. In terms of mobility, 32.84% ( n  = 22/67) of patients between the ages 4 and 16 years old were found to be mobile. As many as 36.07% of patients ranging from 5 to 16 years of age ( n  = 22/61) received formal education ranging from preschool to secondary school. The prevalence of spina bifida in UMMC is as according to

  8. Surrogate Pregnancy After Prenatal Diagnosis of Spina Bifida.

    Science.gov (United States)

    Mazur, Lynnette J; Kisthardt, Mary Kay; Kim, Helen H; Rosas, Laura M; Lantos, John D

    2017-02-01

    Some pregnancies today involve infertile individuals or couples who contract with a fertile woman to carry a pregnancy for them. The woman who carries the pregnancy is referred to as a "gestational carrier." The use of such arrangements is increasing. Most of the time, these arrangements play out as planned; sometimes, however, problems arise. This article discusses a case in which a fetal diagnosis of spina bifida led the infertile couple to request that the gestational carrier terminate the pregnancy, and the gestational carrier did not wish to do so. Experts in the medical and legal issues surrounding surrogacy discuss the considerations that should go into resolving such a conflict. Copyright © 2017 by the American Academy of Pediatrics.

  9. Selective and sustained attention in children with spina bifida myelomeningocele

    DEFF Research Database (Denmark)

    Caspersen, Ida Dyhr; Habekost, Thomas

    2013-01-01

    distinguish perceptual from response-related components of attention. We used a verbal-report paradigm based on the Theory of Visual Attention (Bundesen, 1990) and a new continuous performance test, the Dual Attention to Response Task (Dockree et al., 2006), for measuring parameters of selective and sustained......Spina bifida myelomeningocele (SBM) is a neural tube defect that has been related to deficits in several cognitive domains including attention. Attention function in children with SBM has often been studied using tasks that are confounded by complex motor demands or tasks that do not clearly...... attention in 6 children with SBM and 18 healthy control children. The two tasks had minimal motor demands, were functionally specific and were sensitive to minor deficits. As a group, the children with SBM were significantly less efficient at filtering out irrelevant stimuli. Moreover, they exhibited...

  10. Quality of life among children with spina bifida in Uganda.

    Science.gov (United States)

    Sims-Williams, Helen J; Sims-Williams, Hugh P; Mbabazi Kabachelor, Edith; Warf, Benjamin C

    2017-11-01

    Children surviving after spina bifida repair often have significant disability, the consequences of which may be more profound in low-income countries. The aim of this cross-sectional study was to measure quality of life (QOL) reported by children with spina bifida in Uganda, and to define factors associated with QOL. QOL was measured using both the Health Utilities Index (HUI3) Tool and a visual analogue scale (VAS) marked from 0 to 10. In keeping with the WHO definition of QOL, further analysis was conducted using subjective QOL scores (using the VAS). Multivariate regression was used to investigate the association between VAS scores and prespecified variables: age, sex, hydrocephalus, mobility, urinary continence, school attendance and family size. Sixty two of 68 surviving children aged 10-14 were able to complete all aspects of the assessment. There was poor correlation between the VAS and HUI3 Tool (Pearson correlation 0.488). On multivariate regression, the following variables were associated with a significant change in the 10-point VAS (change in score; 95% CI): male sex (-1.45; -2.436 to -0.465), urinary continence (1.681; 0.190 to 3.172), large family size (-1.775; -2.773 to -0.777) and hydrocephalus (-1.382; -2.374 to -0.465). Urinary continence and family size are potentially modifiable, the former by simple and inexpensive medical management. Enhanced investment in community-based rehabilitation and support is urgently needed. Delivery of family planning services is a national priority in Uganda, and should be discussed with families as part of holistic care. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Small renal size in newborns with spina bifida: possible causes.

    Science.gov (United States)

    Montaldo, Paolo; Montaldo, Luisa; Iossa, Azzurra Concetta; Cennamo, Marina; Caredda, Elisabetta; Del Gado, Roberto

    2014-02-01

    Previous studies reported that children with neural tube defects, but without any history of intrinsic renal diseases, have small kidneys when compared with age-matched standard renal growth. The aim of this study was to investigate the possible causes of small renal size in children with spina bifida by comparing growth hormone deficiency, physical limitations and hyperhomocysteinemia. The sample included 187 newborns with spina bifida. Renal sizes in the patients were assessed by using maximum measurement of renal length and the measurements were compared by using the Sutherland monogram. According to the results, the sample was divided into two groups--a group of 120 patients with small kidneys (under the third percentile) and a control group of 67 newborns with normal kidney size. Plasma total homocysteine was investigated in mothers and in their children. Serum insulin-like growth factor-1 (IGF-1) levels were measured. Serum IGF-1 levels were normal in both groups. Children and mothers with homocysteine levels >10 μmol/l were more than twice as likely to have small kidneys and to give to birth children with small kidneys, respectively, compared with newborns and mothers with homocysteine levels <10 μmol/l. An inverse correlation was also found between the homocysteine levels of mothers and kidney sizes of children (r = - 0.6109 P ≤ 0.01). It is highly important for mothers with hyperhomocysteinemia to be educated about benefits of folate supplementation in order to reduce the risk of small renal size and lower renal function in children.

  12. Maternal myo-inositol, glucose, and zinc status is associated with the risk of offspring with spina bifida.

    NARCIS (Netherlands)

    Groenen, P.; Peer, P.G.M.; Wevers, R.A.; Swinkels, D.W.; Franke, B.; Mariman, E.C.M.; Steegers-Theunissen, R.P.M.

    2003-01-01

    OBJECTIVE: The purpose of this study was to investigate the maternal and children's myo-inositol, glucose, and zinc status in association with spina bifida risk. STUDY DESIGN: Sixty-three mothers and 70 children with spina bifida and 102 control mothers and 85 control children were investigated. The

  13. Audit of prenatal and postnatal diagnosis of isolated open spina bifida in three university hospitals in The Netherlands

    NARCIS (Netherlands)

    Olde Scholtenhuis, M. A. G.; Cohen-Overbeek, T. E.; Offringa, M.; Barth, P. G.; Stoutenbeek, Ph; Gooskens, R. H.; Wladimiroff, J. W.; Bilardo, C. M.

    2003-01-01

    Objective To audit the current Dutch policy of prenatal detection of isolated open spina bifida based on offering detailed ultrasound examination only on indication. Methods A retrospective analysis of prenatally diagnosed isolated spina bifida cases and of newborns diagnosed with this condition was

  14. Hospitalization for urinary tract infections and the quality of preventive health care received by people with spina bifida.

    Science.gov (United States)

    Armour, Brian S; Ouyang, Lijing; Thibadeau, Judy; Grosse, Scott D; Campbell, Vincent A; Joseph, David

    2009-07-01

    The preventive health care needs of people with disabilities often go unmet, resulting in medical complications that may require hospitalization. Such complications could be due, in part, to difficulty accessing care or the quality of ambulatory care services received. To use hospitalizations for urinary tract infections (UTIs) as a marker of the potential quality of ambulatory care services received by people affected by spina bifida. MarketScan inpatient and outpatient medical claims data for 2000 through 2003 were used to identify hospitalizations for UTI, which is an ambulatory care sensitive condition, for people affected by spina bifida and to calculate inpatient discharge rates, average lengths of stay, and average medical care expenditures for such hospitalizations. People affected by spina bifida averaged 0.5 hospitalizations per year, and there were 22.8 inpatient admissions with UTI per 1000 persons with spina bifida during the period 2000-2003, in comparison to an average of 0.44 admission with UTI per 1000 persons for those without spina bifida. If the number of UTI hospitalizations among people affected by spina bifida were reduced by 50%, expenditures could be reduced by $4.4 million per 1000 patients. Consensus on the evaluation and management of bacteriuria could enhance clinical care and reduce the disparity in UTI discharge rates among people affected by spina bifida compared to those without spina bifida. National evidence-based guidelines are needed.

  15. Genetic variation in biotransformation enzymes, air pollution exposures, and risk of spina bifida.

    Science.gov (United States)

    Padula, Amy M; Yang, Wei; Schultz, Kathleen; Lurmann, Fred; Hammond, S Katharine; Shaw, Gary M

    2018-05-01

    Spina bifida is a birth defect characterized by incomplete closure of the embryonic neural tube. Genetic factors as well as environmental factors have been observed to influence risks for spina bifida. Few studies have investigated possible gene-environment interactions that could contribute to spina bifida risk. The aim of this study is to examine the interaction between gene variants in biotransformation enzyme pathways and ambient air pollution exposures and risk of spina bifida. We evaluated the role of air pollution exposure during pregnancy and gene variants of biotransformation enzymes from bloodspots and buccal cells in a California population-based case-control (86 cases of spina bifida and 208 non-malformed controls) study. We considered race/ethnicity and folic acid vitamin use as potential effect modifiers and adjusted for those factors and smoking. We observed gene-environment interactions between each of the five pollutants and several gene variants: NO (ABCC2), NO 2 (ABCC2, SLC01B1), PM 10 (ABCC2, CYP1A1, CYP2B6, CYP2C19, CYP2D6, NAT2, SLC01B1, SLC01B3), PM 2.5 (CYP1A1 and CYP1A2). These analyses show positive interactions between air pollution exposure during early pregnancy and gene variants associated with metabolizing enzymes. These exploratory results suggest that some individuals based on their genetic background may be more susceptible to the adverse effects of pollution. © 2018 Wiley Periodicals, Inc.

  16. Health care expenditures of children and adults with spina bifida in a privately insured U.S. population.

    Science.gov (United States)

    Ouyang, Lijing; Grosse, Scott D; Armour, Brian S; Waitzman, Norman J

    2007-07-01

    We provide new estimates of medical care utilization and expenditures over the lifespan for persons living with spina bifida in the United States. Updated estimates are essential for calculations of lifetime costs and for economic evaluations of prevention and management strategies for spina bifida. We analyzed data from the 2001-2003 MarketScan database on paid medical and prescription drug claims of persons covered by employer-sponsored health insurance in the United States. Medical care utilization and expenditures during 2003 were analyzed for persons with a diagnosis of spina bifida recorded during 2001-2003 who had 12 months of coverage in a fee-for-service health plan. To calculate expenditures during infancy, a separate analysis was performed for those born during 2002 with claims and expenditures data during the first 12 months of life. We compared medical expenditures for persons with and without spina bifida by age groups. Average incremental medical expenditures comparing patients with spina bifida and those without were $41,460 per year at age 0, $14,070 at ages 1-17, $13,339 at ages 18-44, and $10,134 at ages 45-64. Children ages 1-17 years with spina bifida had average medical expenditures 13 times greater than children without spina bifida. Adults with spina bifida had average medical expenditures three to six times greater than adults without spina bifida in this privately insured population. Although per capita medical care utilization and expenditures are highest among children, adults constitute an important and growing share of the population living with spina bifida. (c) 2007 Wiley-Liss, Inc.

  17. Communicating about obesity and weight-related topics with children with a physical disability and their families: spina bifida as an example.

    Science.gov (United States)

    McPherson, Amy C; Swift, Judy A; Peters, Michelle; Lyons, Julia; Joy Knibbe, Tara; Church, Paige; Chen, Lorry; Farrell, Renée M; Willem Gorter, Jan

    2017-04-01

    The purpose of this study was to explore the experiences of children with spina bifida (SB), their families and healthcare professionals (HCPs) when discussing weight-related topics. In-depth qualitative interviews were conducted with HCPs from Canadian outpatient SB clinics (n = 13), children aged 6-18 years with SB (n = 17) and their parents (n = 20). Data were analyzed using a phenomenological approach within an interpretative paradigm. Many HCPs were not confident talking about weight, concerned that they would damage relationships with children and families. Parents wanted routine weight surveillance, but were worried about their children's self-esteem if their weight was discussed. They wanted HCPs to acknowledge the challenges of weight management in children with a physical disability and provide specialized solutions. Children wanted a positively framed and tailored approach to weight discussions, although this had generally not been their experience. Stakeholders describe therapeutic relationships that are currently disconnected around the issue of weight and obesity. However, children, parents and HCPs all believed that discussing this topic was critical. Positively framed, strengths-based and tailored approaches to weight-related discussions are warranted. Implications for Rehabilitation Rates of overweight and obesity in children and youth with physical disabilities are substantially higher than their typically developing peers. Healthcare professionals, children with physical disabilities and families often find weight-related discussions challenging and disconnected. Weight-related discussions should be tailored to the child and family's circumstances and priorities. Positively framed and strengths-based approaches to weight-related discussions are warranted.

  18. Subluxation and dislocation of the hip in children with spina bifida (review

    Directory of Open Access Journals (Sweden)

    A. G. Baindurashvili

    2013-01-01

    Full Text Available Subluxation or dislocation of the hip joint develops in 30-50% children with spina bifida during the first 2-3 years of life. These problems results from force disbalance between muscle group and other structural changes of the hip and pelvis components of the joint. The goal of treatment subluxation and dislocation of the hip joint in children with spina bifida is to make comfortable daily functions, eliminate the pain, provide the mobility and social independent. Management of subluxation and dislocation in children with spina bifida had changed in the last years because of the analysis long-term results. Indications for surgical treatment were determined more clearly, what made the results of treatment better.

  19. Labor market productivity costs for caregivers of children with spina bifida: a population-based analysis.

    Science.gov (United States)

    Tilford, John M; Grosse, Scott D; Goodman, Allen C; Li, Kemeng

    2009-01-01

    Caregiver productivity costs are an important component of the overall cost of care for individuals with birth defects and developmental disabilities, yet few studies provide estimates for use in economic evaluations. This study estimates labor market productivity costs for caregivers of children and adolescents with spina bifida. Case families were recruited from a state birth defects registry in Arkansas. Primary caregivers of children with spina bifida (N = 98) reported their employment status in the past year and demographic characteristics. Controls were abstracted from the Current Population Survey covering the state of Arkansas for the same time period (N = 416). Estimates from regression analyses of labor market outcomes were used to calculate differences in hours worked per week and lifetime costs. Caregivers of children with spina bifida worked an annual average of 7.5 to 11.3 hours less per week depending on the disability severity. Differences in work hours by caregivers of children with spina bifida translated into lifetime costs of $133,755 in 2002 dollars using a 3% discount rate and an age- and sex-adjusted earnings profile. Including caregivers' labor market productivity costs in prevention effectiveness estimates raises the net cost savings per averted case of spina bifida by 48% over the medical care costs alone. Information on labor market productivity costs for caregivers can be used to better inform economic evaluations of prevention and treatment strategies for spina bifida. Cost-effectiveness calculations that omit caregiver productivity costs substantially overstate the net costs of the intervention and underestimate societal value.

  20. The longest faun tail forming dreadlocks with underlying spina bifida occulta.

    Science.gov (United States)

    Brar, Balvinder Kaur; Mahajan, Bharat Bhushan; Mittal, Jyotisterna

    2013-04-15

    Spina bifida is a developmental anomaly characterized by defective closure of the bony encasement of the spinal cord through which the spinal cord and meninges may or may not protrude. We report a rare case of a very long faun tail, which was in the form of a 20 inch long tail originating from the lumbosacral area in a rhomboidal pattern, measuring 10 x 8 inches. The case is being reported for its rare presentation of a 20 inch long faun tail with underlying spina bifida occulta.

  1. Profesi Epidemiologi

    Directory of Open Access Journals (Sweden)

    Buchari Lapau

    2011-01-01

    Full Text Available Makalah ini pertama kali menjelaskan perlu adanya profesi kesehatan masyarakat dalam rangka pembangunan kesehatan. Lalu dijelaskan apa profesi itu dan standar keberadaan profesi, atas dasar mana dapat ditetapkan bahwa pelayanan epidemiologi merupakan salah satu profesi. Dalam rangka pembinaan profesi kesehatan masyarakat, IAKMI dan APTKMI telah membentuk Majelis Kolegium Kesehatan Masyarakat Indonesia (MKKMI yang terdiri atas 8 kolegium antara lain Kolegium Epidemiologi, yang telah menyusun Standar Profesi Epidemiologi yang terdiri atas beberapa standar. Masing-masing standar dijelaskan mulai dari kurikulum, standar pelayanan epidmiologi, profil epidemiolog kesehatan, peran epidemiolog kesehatan, fungsi epidemiolog kesehatan, standar kompetensi epidemiologi, dan standar pendidikan profesi epidemiologi.

  2. Growth and characterization of an InSb infrared photoconductor on Si via an AlSb/GaSb buffer

    Science.gov (United States)

    Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt

    2018-05-01

    A 99.6% relaxed InSb layer is grown on a 6° offcut (1 0 0) Si substrate via an AlSb/GaSb buffer using molecular beam epitaxy (MBE). A 200 nm GaSb buffer is first grown on Si and the lattice mismatch between them is accommodated by an interfacial misfit (IMF) array consisting of uniformly distributed 90° misfit dislocations. Si delta doping is introduced during the growth of GaSb to reduce the density of threading dislocation. Subsequently, a 50 nm AlSb buffer is grown followed by a 0.8 μm InSb layer. The InSb layer exhibits a 300 K electron mobility of 22,300 cm2/Vs. An InSb photoconductor on Si is demonstrated with a photoconductive gain from 77 K to 200 K under a 700 °C maintained blackbody.

  3. Diffusion tensor magnetic resonance imaging and fiber tractography of the sacral plexus in children with spina bifida

    DEFF Research Database (Denmark)

    Haakma, Wieke; Dik, Pieter; ten Haken, Bennie

    2014-01-01

    anatomical and microstructural properties of the sacral plexus of patients with spina bifida using diffusion tensor imaging and fiber tractography. MATERIALS AND METHODS: Ten patients 8 to 16 years old with spina bifida underwent diffusion tensor imaging on a 3 Tesla magnetic resonance imaging system...... diffusivity values at S1-S3 were significantly lower in patients. CONCLUSIONS: To our knowledge this 3 Tesla magnetic resonance imaging study showed for the first time sacral plexus asymmetry and disorganization in 10 patients with spina bifida using diffusion tensor imaging and fiber tractography...

  4. Spina bifida: implications for cognitive functioning, disability and health in young adults

    NARCIS (Netherlands)

    Barf, H.A.

    2008-01-01

    Spina bifida is a developmental birth defect involving the neural tube. It can result in a variety of problems, amongst them incontinence, restrictions of mobility and restrictions of cognitive functioning, depending on the severity of the defect. Due to improvements in medical care, the life

  5. Work participation among young adults with spina bifida in the Netherlands

    NARCIS (Netherlands)

    van Mechelen, M. C.; Verhoef, M.; van Asbeck, F. W. A.; Post, M. W. M.

    2008-01-01

    The aim of this study was to: (1) assess work participation among young adults with spina bifida, (2) identify problems perceived in finding employment, and (3) examine which determinants are related to work participation. This cross-sectional study was a follow-up study to the Adolescents with

  6. First-trimester visualization of the fourth ventricle in fetuses with and without spina bifida.

    Science.gov (United States)

    Solt, Ido; Acuna, Joann G; Adeniji, Beni A; Mirocha, James; Kim, Matthew J; Rotmensch, Siegfried

    2011-12-01

    The purpose of this study was to examine the efficacy of nonvisualization of the fourth ventricle for first-trimester detection of spina bifida. A total of 250 digitally stored sonographic examinations at gestational ages of 11 weeks to 13 weeks 6 days (245 normal and 5 randomly interspersed spina bifida cases) were retrospectively analyzed by 4 blinded reviewers for the presence or absence of the fourth ventricle followed by an anteroposterior ventricular dimension measurement. The ventricle size was related to the crown-rump length and gestational age by linear regression analysis and Pearson correlation. The fourth ventricle was identified in 971 of 1000 image readings (97.1%). False-negative and false-positive readings occurred in 11 of 20 (55.0%) and 20 of 980 (2.0%) cases, respectively (sensitivity, 0.45; specificity, 0.98.). False-negative and false-positive readings were evenly distributed throughout the gestational age range. When the ventricular size was measurable, its mean dimensions increased linearly with gestational age and were below the fifth percentile in 10 of 245 (4.0%) normal and 0 of 4 spina bifida cases, respectively. Intraclass correlation coefficient estimates were calculated based on the 2-way analysis of variance model and found to be 0.30 for a single rater and 0.64 for the mean of 4 raters. Nonvisualization of the first-trimester fourth ventricle is a less robust screening parameter for spina bifida than previously published.

  7. Home screening for bacteriuria in children with spina bifida and clean intermittent catheterization

    Directory of Open Access Journals (Sweden)

    Zegers Bas SHJ

    2012-10-01

    Full Text Available Abstract Background Significant bacteriuria (SBU and urinary tract infections (UTIs are common in patients with spina bifida and neuropathic detrusor sphincter dysfunction. Laboratory agar plated culture is the gold standard to establish SBU. It has the disadvantage of diagnostic and subsequent therapeutic delay. Leukocyte esterase tests (LETs and dip slides proved to be useful in the general populations to exclude SBU and UTI. The aim of this study was to evaluate the reliability of LET and dip slide in children with spina bifida without symptoms of UTI. The reliability in children with asymptomatic SBU was not studied before. Methods In one hundred and twelve children with spina bifida on clean intermittent catheterization LETs and dip slides were compared with laboratory cultures. Both tests and agar plated cultures were performed on catheterized urine samples. The hypothesis was that the home tests are as accurate as laboratory cultures. Results A SBU was found in 45 (40% of the 112 laboratory cultures. A negative LET excluded SBU (negative predictive value 96%, while a positive LET had a positive predictive value of 72%. The false positive rate was 28%. Dip slide determination of bacterial growth had no added value, other than serving as transport medium. Conclusions In spina bifida children, leukocyte esterase testing can be used to exclude significant bacteriuria at home, while dip slide tests have no added value to diagnose or exclude significant bacteriuria.

  8. A Pregnant Woman with Spina Bifida: Need for a Multidisciplinary Labor Plan

    Directory of Open Access Journals (Sweden)

    Mary Angela O’Neal

    2017-10-01

    Full Text Available Women with spina bifida present both obstetrical and anesthesia challenges. They are more likely to require a caesarian delivery and traditionally neuraxial anesthesia has been avoided due to concerns of worsening neurologic disability. The case of a pregnant woman with a history of a surgically corrected lipomeningocele and tethered cord is presented to illustrate the need for a comprehensive labor plan.

  9. Is autonomy related to the quality of performance of everyday activities in children with spina bifida?

    Science.gov (United States)

    Peny-Dahlstrand, Marie; Krumlinde-Sundholm, Lena; Gosman-Hedström, Gunilla

    2012-01-01

    To investigate the relationship between the level of autonomy and the quality of performance of everyday activities in a population-based cohort of children with spina bifida and to study the agreement between the children's and the parents' ratings of autonomy. 50 dyads of children (aged 6-14) with spina bifida and their parents rated the children's level of autonomy with an adapted, Swedish version of the Autonomy Scale from the Arc's Self-Determination Scale. Each child's quality of performance of everyday activities was assessed with the Assessment of Motor and Process Skills (AMPS). The autonomy levels of the children with spina bifida were rated to be lowest in daily routines and highest in leisure activities. Binary logistic regression analyses revealed that age, motor skills and process skills were all significantly related to the autonomy level, but that process skills appeared to predominate in this respect. Concerning the perception of the autonomy level, little agreement was found between each child and his/her parent. It is important to understand and support the development of process skills as expressed in task performance in children with spina bifida and to pay attention to both the parent's and the child's opinion when setting goals and plans for interventions.

  10. Treatment of pressure sores in spina bifida patients with calcium alginate and foam dressings.

    Science.gov (United States)

    Ausili, E; Paolucci, V; Triarico, S; Maestrini, C; Murolo, D; Focarelli, B; Rendeli, C

    2013-06-01

    Prospective study on local treatment of pressure sores using calcium alginate and foam dressings in spina bifida patients. Investigate if this sequential approach is valid and safe for selected patients with neurological impairments. Using European Pressure Ulcer Grading System, after clinical evaluation of local sore, selected patients of Spina Bifida Center of Rome were treated with sequential calcium alginate and foam dressings for 12 weeks. Pressure ulcere surfaces were measured monthly by ulcer tracing. The endpoints were the mean absolute areas surface reduction during every month and number of patients achieving a 50% or more during study. 14 patients (7 males aged 12-24 years) with spina bifida and pressure sores were treated. Mean and standard deviation of mean surface area reduction were 12.5 ± 7.5 cm 2 at start of the study versus 3.7 ± 5.2 cm 2 after 12 weeks, p pressure sores in selected patients with spina bifida. In fact, they protect the wound and create an environment favorable to healing.

  11. Neurological bypass for sensory innervation of the penis in patients with spina bifida

    NARCIS (Netherlands)

    Overgoor, Max L. E.; Kon, Moshe; Cohen-Kettenis, Peggy T.; Strijbos, Saskia A. M.; de Boer, Niels; de Jong, Tom P. V. M.

    2006-01-01

    Most male patients with spina bifida have normal sexual desires. During puberty they begin to realize that they can achieve erection and sexual intercourse but without any sensation in the penis. We hypothesized that restored sensation in the penis would greatly contribute to their quality of life

  12. The Language of Children with Spina Bifida and Hydrocephalus: Meeting Task Demands and Mastering Syntax.

    Science.gov (United States)

    Byrne, Karen; And Others

    1990-01-01

    Linguistic performance of 7 children (mean age=68 months) with spina bifida, hydrocephalus, and average intelligence was evaluated. Subjects dealt with the semantic-pragmatic requirements of linguistically posed problems in an age-appropriate manner. Performance declined as task demands increased but no more than performance of nondisabled…

  13. Mother and Child Depressive Symptoms in Youth with Spina Bifida: Additive, Moderator, and Mediator Models

    Science.gov (United States)

    Schellinger, Kriston B.; Holmbeck, Grayson N.; Essner, Bonnie S.; Alvarez, Renae

    2012-01-01

    The purpose of the study was to examine the extent to which parenting behaviors influence the relation between maternal and child depressive symptoms in youth with spina bifida and a comparison sample. Previous research has found that maternal depression not only negatively impacts the mother-child relationship, but also places the child at risk…

  14. The Management and Education of Children with Spina Bifida and Hydrocephalus.

    Science.gov (United States)

    Andrews, Robert J.; Elkins, John

    The report describes the population of children in Australia with spina bifida and/or hydrocephalus, notes their needs and characteristics, reviews their school placement and social circumstances, and considers future educational services for them. Initial chapters review the literature on medical, psychoeducational, and social-family aspects of…

  15. Spinal hemorrhages are associated with early neonatal motor function loss in human spina bifida aperta

    NARCIS (Netherlands)

    Sival, Deborah; Verbeek, R. J.; Brouwer, O. F.; Sollie, K. M.; Bos, A. F.; den Dunnen, W. F. A.

    Background: In spina bifida aperta (SBA), leg movements caudal to the meningomyelocele are present in utero, but they disappear shortly after birth. It is unclear whether leg movements disappear by impact of the neuro-developmental malformation or by superimposed traumatic damage. If superimposed

  16. The results of Grice Green subtalar arthrodesis of valgus foot in spina bifida

    Directory of Open Access Journals (Sweden)

    Fatih Küçükdurmaz

    2012-01-01

    Full Text Available Background: Valgus foot is a common foot deformity in spina bifida. The most popular operation for the valgus deformity has been the Grice talocalcaneal blocking. It has not been studied primarily in children with spina bifida. We report a prospective series, we present the results of hind foot valgus deformity of children with spina bifida, using Grice talocalcaneal arthrodesis with a tricortical iliac bone graft. Materials and Methods: Between May 2000 and December 2003, 21 patients with bilateral (42 feet valgus deformity of feet underwent surgery. There were 7 males and 14 females. The mean age of patients was 67.7 months (range 50-108 months. Results: The total number of feet that had nonunion was 11, in 7 of them the grafts were completely reabsorbed and the outcome of all these feet was unsatisfactory. Four feet had partial union of which three had unsatisfactory and one had satisfactory outcome. Sixteen feet had residual valgus deformity at the last followup visit, 10 patients had nonunion, and 6 had inadequate correction. Mean preoperative talocalcaneal and calcaneal pitch angles were 48.5΀ and 31.9΀, respectively, which decreased to 38.5΀ and 29.1΀, respectively, postoperatively. The decrease in talocalcaneal angle and calcaneal pitch was significant between preoperative and postoperative measurements (P<0.05. Conclusion: Grice subtalar arthrodesis technique is still a valuable option for valgus foot in patients with spina bifida. In this study, we found more encouraging results in older patients.

  17. DWPF SB6 Initial CPC Flowsheet Testing SB6-1 TO SB6-4L Tests Of SB6-A And SB6-B Simulants

    International Nuclear Information System (INIS)

    Lambert, D.; Pickenheim, B.; Best, D.

    2009-01-01

    The Defense Waste Processing Facility (DWPF) will transition from Sludge Batch 5 (SB5) processing to Sludge Batch 6 (SB6) processing in late fiscal year 2010. Tests were conducted using non-radioactive simulants of the expected SB6 composition to determine the impact of varying the acid stoichiometry during the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processes. The work was conducted to meet the Technical Task Request (TTR) HLW/DWPF/TTR-2008-0043, Rev.0 and followed the guidelines of a Task Technical and Quality Assurance Plan (TT and QAP). The flowsheet studies are performed to evaluate the potential chemical processing issues, hydrogen generation rates, and process slurry rheological properties as a function of acid stoichiometry. These studies were conducted with the estimated SB6 composition at the time of the study. This composition assumed a blend of 101,085 kg of Tank 4 insoluble solids and 179,000 kg of Tank 12 insoluble solids. The current plans are to subject Tank 12 sludge to aluminum dissolution. Liquid Waste Operations assumed that 75% of the aluminum would be dissolved during this process. After dissolution and blending of Tank 4 sludge slurry, plans included washing the contents of Tank 51 to ∼1M Na. After the completion of washing, the plan assumes that 40 inches on Tank 40 slurry would remain for blending with the qualified SB6 material. There are several parameters that are noteworthy concerning SB6 sludge: (1) This is the second batch DWPF will be processing that contains sludge that has had a significant fraction of aluminum removed through aluminum dissolution; (2) The sludge is high in mercury, but the projected concentration is lower than SB5; (3) The sludge is high in noble metals, but the projected concentrations are lower than SB5; and(4) The sludge is high in U and Pu - components that are not added in sludge simulants. Six DWPF process simulations were completed in 4-L laboratory-scale equipment using

  18. The adverse influence of spina bifida occulta on the medical treatment outcome of primary monosymptomatic nocturnal enuresis

    Directory of Open Access Journals (Sweden)

    Basri Cakiroglu

    2014-12-01

    Full Text Available Objective: Previous reports have suggested that the incidence of spina bifida occulta (SBO in patients with primary monosymptomatic nocturnal enuresis (PMNE is higher than the general population. The purpose of this study was to investigate the effect of spina bifida occulta on the medical treatment outcome of PMNE. Material and Methods: Between January 2008 and December 2011, a total of 223 children (151 boys and 72 girls, aged 6-16 years; mean age: 10.1 ± 3.04 years with PMNE were reviewed retrospectively. All of the children underwent physical examination, urine analysis, urinary tract ultrasonography and kidney ureter bladder (KUB scout film. All patients were initially treated with a timed voiding program and were given desmopressin acetate when necessary. Results: Spina bifida occulta was detected in 75 children (33.6%. Spina bifida occulta affected L4 in 2 children, L5 in 6 children, L4-L5 in 3 children, S1 in 52 children, S2 in 7 children and S1-S2 in 2 children. Treatment was successful in 79% of the children without SBO, and in only 48% of the children with SBO. Medical treatment success rates differed significantly between the study groups. Conclusion: The presence of spina bifida occulta significantly affects the response to medical treatment in patients with PMNE. Thus, verifying spina bifida occulta status in PMNE can facilitate prognostic predictions about the response to medical treatment.

  19. Distribution, speciation and availability of antimony (Sb) in soils and terrestrial plants from an active Sb mining area

    International Nuclear Information System (INIS)

    Okkenhaug, Gudny; Zhu Yongguan; Luo Lei; Lei Ming; Li Xi; Mulder, Jan

    2011-01-01

    Here, we present one of the first studies investigating the mobility, solubility and the speciation-dependent in-situ bioaccumulation of antimony (Sb) in an active Sb mining area (Xikuangshan, China). Total Sb concentrations in soils are high (527-11,798 mg kg -1 ), and all soils, including those taken from a paddy field and a vegetable garden, show a high bioavailable Sb fraction (6.3-748 mg kg -1 ), dominated by Sb(V). Elevated concentrations in native plant species (109-4029 mg kg -1 ) underpin this. Both chemical equilibrium studies and XANES data suggest the presence of Ca[Sb(OH) 6 ] 2 , controlling Sb solubility. A very close relationship was found between the citric acid extractable Sb in plants and water or sulfate extractable Sb in soil, indicating that citric acid extractable Sb content in plants may be a better predictor for bioavailable Sb in soil than total acid digestible Sb plant content. - Highlights: → Antimony (Sb) in soils from an active Sb mining area is highly bioavailable. → Sb occurs mainly as Sb(V) in Sb mining impacted soils and plants. → Sb solubility in Sb mining impacted soils is governed by Ca[Sb(OH) 6 ] 2 . → Citric acid extractable Sb in plants and bioavailable Sb in soils are strongly correlated. - Antimony (Sb) in soils from an active Sb mining area is highly bioavailable and controlled by the solubility of calcium antimonate.

  20. Medical adherence in young adolescents with spina bifida: longitudinal associations with family functioning.

    Science.gov (United States)

    Stepansky, Mona A; Roache, Caitlin R; Holmbeck, Grayson N; Schultz, Karen

    2010-03-01

    The purpose of this study was 2-fold: (1) to explore the transfer of responsibility of medical tasks from parent to child during the transition to adolescence, and (2) to examine the associations between family functioning and medical adherence in youth with spina bifida. Seventy families of children with spina bifida participated in this study. Data were collected during family interaction sessions by using questionnaires completed by mothers, fathers, youth, teachers and health professionals. Findings suggest that responsibility for medical regimens transfers gradually from parent to child over time. Additionally, family conflict and cohesion were correlated with medical adherence. Finally, family conflict over medical issues was related to a decrease in medical adherence over time. Results suggest that as youth take more responsibility over their medical regimens, family conflict regarding medical issues becomes a contributor to their adherence behaviors. Interventions that target family conflict may facilitate adherence behaviors.

  1. Primary care providers and medical homes for individuals with spina bifida.

    Science.gov (United States)

    Walker, William O

    2008-01-01

    The contributions of primary care providers to the successful care of children with spina bifida cannot be underestimated. Overcoming systemic barriers to their integration into a comprehensive care system is essential. By providing routine and disability specific care through the structure of a Medical Home, they are often the first line resource and support for individuals and their families. The Medical Home model encourages primary care providers to facilitate discussions on topics as varied as education and employment. Knowledge of specific medical issues unique to this population allows the primary care provider to complement the efforts of other specialty clinics and providers in often neglected areas such as sexual health, obesity and latex sensitization. As individuals with spina bifida live into adulthood, and access to traditional multidisciplinary care models evolves, these skills will take on increasing importance within the scope of providing comprehensive and coordinated care.

  2. Posterior brain in fetuses with open spina bifida at 11 to 13 weeks.

    Science.gov (United States)

    Lachmann, Robert; Chaoui, Rabih; Moratalla, Jose; Picciarelli, Gemma; Nicolaides, Kypros H

    2011-01-01

    To measure the changes in the posterior fossa in first-trimester fetuses with open spina bifida (OSB). The brain stem diameter and brain stem to occipital bone (BSOB) diameter were measured in stored images of the mid-sagittal view of the fetal face at 11(+0) to 13(+6) weeks from 30 fetuses with OSB and 1000 normal controls. In the control group, the brain stem and BSOB diameter increased significantly with crown-rump length (CRL) and the brain stem to BSOB ratio decreased. In the spina bifida group, the brain stem diameter was above the 95th percentile of the control group in 29 (96.7%) cases, the BSOB diameter was below the 5th percentile in 26 (86.7%) and the brain stem to BSOB ratio was above the 95th percentile in all cases. At 11 to 13 weeks the majority of fetuses with OSB have measurable abnormalities in the posterior brain.

  3. Bonding in ZnSb

    DEFF Research Database (Denmark)

    Bjerg, Lasse; Madsen, Georg K. H.; Iversen, Bo Brummerstedt

    Thermoelectric materials are capable of converting waste heat into usable electric energy. The conversion efficiency depends critically on the electronic band structure. Theoretical calculations predict the semiconducting ZnSb to have a promising efficiency if it is n-doped. The details of the lo......Thermoelectric materials are capable of converting waste heat into usable electric energy. The conversion efficiency depends critically on the electronic band structure. Theoretical calculations predict the semiconducting ZnSb to have a promising efficiency if it is n-doped. The details...... of the lowest conduction band have therefore been investigated. Electrons placed in the lowest conduction band are predicted to increase the bonding between second nearest neighbour atoms. This causes a lowering of the energy at special points in the first Brillouin zone. Thereby, the dispersion of the lowest...

  4. Neurological bypass for sensory innervation of the penis in patients with spina bifida.

    Science.gov (United States)

    Overgoor, Max L E; Kon, Moshe; Cohen-Kettenis, Peggy T; Strijbos, Saskia A M; de Boer, Niels; de Jong, Tom P V M

    2006-09-01

    Most male patients with spina bifida have normal sexual desires. During puberty they begin to realize that they can achieve erection and sexual intercourse but without any sensation in the penis. We hypothesized that restored sensation in the penis would greatly contribute to their quality of life and sexual health. In this prospective study we investigated the outcome of a new operative neurological bypass procedure in patients with spina bifida. In 3 patients who were 17, 18 and 21 years old with a spinal lesion at L5, L4 and L3-L4, respectively, the sensory ilioinguinal nerve (L1) was cut distal in the groin and joined by microneurorrhaphy to the divided ipsilateral dorsal nerve of the penis (S2-4) at the base of the penis. All patients underwent preoperative and postoperative neurological and psychological evaluations. By 15 months postoperatively all patients had achieved excellent sensation on the operated side of the glans penis. They were unequivocally positive about the results and the penis had become more integrated into the body image. In 2 patients masturbation became more meaningful and 1 became more sexually active with and without his partner. The newly designed neurological bypass procedure in patients with spina bifida resulted in excellent sensibility in the glans penis. The new sensation appeared to contribute to the quality of the patient sexuality and sexual functioning as well as to the feeling of being a more normal and complete individual who is more conscious of the penis. This new operation might become standard treatment in patients with spina bifida in the future.

  5. A reproductive history of mothers with spina bifida offspring-a new look at old issues

    Directory of Open Access Journals (Sweden)

    Farley Thomas L

    2006-08-01

    Full Text Available Abstract Background Spina bifida is a disorder of the cerebrospinal fluid system associated with failure of neural tube closure in the fetus. Reproductive history studies of mothers with spina bifida offspring have often been conducted shortly after the affected child's birth. In this study, a large group of community-based mothers were studied after most had completed their families. The aims were to present a more comprehensive reproductive history and to test several hypotheses regarding the nature of spina bifida. Methods Data from 271 mothers was collected by interview 18.3 mean years after the affected child's birth. Data analysis was by χ-square, Fisher exact test and t test with a p value less than 0.05 considered significant. Results Females made up 56.5% of affected offspring (probands and 53.1% of unaffected offspring. The spina bifida and anencephaly recurrence rate was 4.0%. The twinning rate was 8.6/1000 live births. 24.4% of mothers had a history of spontaneous abortion and the rate varied by pregnancy order from 87 to 185/1000 live births. Duration of pregnancies subsequent to probands was shorter for female than male probands. Mean birth weight of probands with high lesions exceeded those with low lesions. A spontaneous abortion preceded female probands more often than males as compared to live births. Affected males with high lesions conceived by white mothers were at greater risk to be spontaneously aborted. Previous inter-gestational interval for mothers with no history of spontaneous abortion was longer for probands than unaffected offspring but not for mothers with a history of spontaneous abortion. Conclusion Overall, and for every major subgroup of these mothers, more affected and unaffected female than male offspring were born. Differences by gender and lesion level among probands and between probands and unaffected offspring were consistent with an etiology of unknown genetic factors, hormonal and/or immune system

  6. A study of the clinical profile and outcome of spina bifida

    Directory of Open Access Journals (Sweden)

    Theophilus Nikita Kumar

    2016-02-01

    Full Text Available Neural tube defects (NTDs are a group of congenital anomalies characterized by defects in dorsal midline structures, including neural tissue, dura, muscle, bone and/or skin. The clinical presentations and the follow-up of these patients requires attention to various end organs besides the nervous system. To evaluate the clinical profile and surgical outcome of children with spina bifida. Out of a total of 74 patients treated at our institute for spina bifida between June 2013 to august 2015, 74 cases of spina bifida were analyzed retrospectively and prospectively. The clinical profile, radiological findings and urodynamic studies were recorded. Craniospinal MRI was done in patients to screen for Arnold Chiari malformations and monitoring of hydrocephalus was done as a management protocol at our institute for these children. All these patients except two underwent surgery for correction and closure of the spinal defect. Associated anomalies were treated accordingly. They were clinically assessed over a mean follow up period of 1.3years, ranging from 2months to 2½ years. 73% of the patients presented in the neonatal age group. Of which, 72% presented with a visible sac over the back.72% of the cases were Myelomeningocoeles. 79% of the defects were in the lumbosacral region.30% presented with sensorimotor loss or bladder bowel incontinence. Sensorimotor improvement was seen in 12.5% after repairing the defect with the help of physiotherapy and braces. 30% of the patients were diagnosed to have hydrocephalus, of which 33% required a CSF diversion procedure. The postoperative course of spina bifida repair was found to be uneventful in 90% of the patients

  7. Association between CFL1 gene polymorphisms and spina bifida risk in a California population

    Directory of Open Access Journals (Sweden)

    Lammer Edward J

    2007-03-01

    Full Text Available Abstract Background CFL1 encodes human non-muscle cofilin (n-cofilin, which is an actin-depolymerizing factor and is essential in cytokinesis, endocytosis, and in the development of all embryonic tissues. Cfl1 knockout mice exhibit failure of neural tube closure at E10.5 and die in utero. We hypothesized that genetic variation within the human CFL1 gene may alter the protein's function and result in defective actin depolymerizing and cellular activity during neural tube closure. Such alterations may be associated with an increased risk for neural tube defects (NTDs. Methods Having re-sequenced the human CFL1 gene and identified five common single nucleotide polymorphisms (SNPs in our target population, we investigated whether there existed a possible association between the genetic variations of the CFL1 gene and risk of spina bifida. Samples were obtained from a large population-based case-control study in California. Allele association, genotype association and haplotype association were evaluated in two different ethnicity groups, non-Hispanic white and Hispanic white. Results Homozygosity for the minor alleles of the SNPs studied (rs652021, rs665306, rs667555, rs4621 and rs11227332 appeared to produce an increased risk for spina bifida. Subjects with the haplotype composed of all minor alleles (CCGGT appeared to have increased spina bifida risk (OR = 1.6, 95% CI: 0.9~2.9, however, this finding is not statistically significant likely due to limited sample size. Conclusion The sequence variation of human CFL1 gene is a genetic modifier for spina bifida risk in this California population.

  8. Self-diffusion in 69Ga121Sb/71Ga123Sb isotope heterostructures

    OpenAIRE

    Bracht, H.; Nicols, S. P.; Haller, E. E.; Silveira, Juan Pedro; Briones Fernández-Pola, Fernando

    2001-01-01

    Gallium and antimony self-diffusion experiments have been performed in undoped 69Ga121Sb/71Ga123Sb isotope heterostructures at temperatures between 571 and 708 °C under Sb- and Ga-rich ambients. Ga and Sb profiles measured with secondary ion mass spectrometry reveal that Ga diffuses faster than Sb by several orders of magnitude. This strongly suggests that the two self-atom species diffuse independently on their own sublattices. Experimental results lead us to conclude that Ga and Sb diffusio...

  9. Self-diffusion in 69Ga121Sb/71Ga123Sb isotope heterostructures

    Science.gov (United States)

    Bracht, H.; Nicols, S. P.; Haller, E. E.; Silveira, J. P.; Briones, F.

    2001-05-01

    Gallium and antimony self-diffusion experiments have been performed in undoped 69Ga121Sb/71Ga123Sb isotope heterostructures at temperatures between 571 and 708 °C under Sb- and Ga-rich ambients. Ga and Sb profiles measured with secondary ion mass spectrometry reveal that Ga diffuses faster than Sb by several orders of magnitude. This strongly suggests that the two self-atom species diffuse independently on their own sublattices. Experimental results lead us to conclude that Ga and Sb diffusion are mediated by Ga vacancies and Sb interstitials, respectively, and not by the formation of a triple defect proposed earlier by Weiler and Mehrer [Philos. Mag. A 49, 309 (1984)]. The extremely slow diffusion of Sb up to the melting temperature of GaSb is proposed to be a consequence of amphoteric transformations between native point defects which suppress the formation of those native defects which control Sb diffusion. Preliminary experiments exploring the effect of Zn indiffusion at 550 °C on Ga and Sb diffusion reveal an enhanced intermixing of the Ga isotope layers compared to undoped GaSb. However, under the same conditions the diffusion of Sb was not significantly affected.

  10. Revision of Ascra with proposition of the bifida species group and description of two new species (Hemiptera: Pentatomidae: Edessinae).

    Science.gov (United States)

    Santos, Bianca Tamires Silva Dos; Silva, Valeria Juliete Da; Fernandes, Jose Antonio Marin

    2015-10-30

    Edessa is comprised of six subgenera, Aceratodes, Ascra, Dorypleura, Edessa, Hypoxys and Pygoda. Ascra is here elevated to genus status based on characteristics of the male and female genitalia and the gibbous pronotum. This genus is comprised of eight species previously placed in Edessa-E. bifida, E. cordifera, E. petersii, E. abdita, E. championi, E. privata, E. conspersa and E. morbosa, as well as six new species. The genus Ascra was further divided into two groups of species bifida and privata separated by a different pattern of punctuation on body and pygophore. Here we present only the bifida species group formed by A. bifida, A. cordifera, A. petersii, A. abdita, and A. championi, as well as two new species-A. vluteum and A. flavoscutellata. Lectotypes of Aceratodes sigillatus, Edessa abdita, E. championi, E. cornuta, E. densata and E. petersii are designated. Aceratodes sigillatus, Edessa cornuta, E. densata, E. picata, and E. florida are considered junior synonyms of A. bifida. Interestingly, some species of this genus are considered edible in Mexico.

  11. Sequential and simultaneous adsorption of Sb(III) and Sb(V) on ferrihydrite: Implications for oxidation and competition.

    Science.gov (United States)

    Qi, Pengfei; Pichler, Thomas

    2016-02-01

    Antimony (Sb) is a naturally occurring element of growing environmental concern whose toxicity, adsorption behavior and other chemical properties are similar to that of arsenic (As). However, less is known about Sb compared to As. Individual and simultaneous adsorption experiments with Sb(III) and Sb(V) were conducted in batch mode with focus on the Sb speciation of the remaining liquid phase during individual Sb(III) adsorption experiments. The simultaneous adsorption and oxidation of Sb(III) was confirmed by the appearance of Sb(V) in the solution at varying Fe/Sb ratios (500, 100 and 8) and varying pH values (3.8, 7 and 9). This newly formed Sb(V) was subsequently removed from solution at a Fe/Sb ratio of 500 or at a pH of 3.8. However, more or less only Sb(V) was observed in the liquid phase at the end of the experiments at lower Fe/Sb ratios and higher pH, indicating that competition took place between the newly formed Sb(V) and Sb(III), and that Sb(III) outcompeted Sb(V). This was independently confirmed by simultaneous adsorption experiments of Sb(III) and Sb(V) in binary systems. Under such conditions, the presence of Sb(V) had no influence on the adsorption of Sb(III) while Sb(V) adsorption was significantly inhibited by Sb(III) over a wide pH range (4-10). Thus, in the presence of ferrihydrite and under redox conditions, which allow the presence of both Sb species, Sb(V) should be the dominant species in aquatic environments, since Sb(III) is adsorbed preferentially and at the same time oxidized to Sb(V). Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Redundant Sb condensation on GaSb epilayers grown by molecular beam epitaxy during cooling procedure

    International Nuclear Information System (INIS)

    Arpapay, B.; Şahin, S.; Arıkan, B.; Serincan, U.

    2014-01-01

    The effect of four different cooling receipts on the surface morphologies of unintentionally-doped GaSb epilayers on GaSb (100) substrates grown by molecular beam epitaxy is reported. Those receipts include three different Sb beam equivalent pressure (BEP) levels and two different termination temperatures. Surface morphologies of epilayers were examined by wet etching, surface profiler, atomic force microscopy, scanning electron microscopy and Raman spectroscopy. The results demonstrate that during the cooling period, a Sb BEP of 4.00 × 10 −4 Pa at a termination temperature of 400 °C induces a smooth surface without Sb condensation whereas same Sb BEP at a termination temperature of 350 °C forms a 300 nm thick Sb layer on the surface. In addition, it is revealed that by applying a wet etching procedure and using a surface profiler it is possible to identify this condensed layer from the two-sloped feature of mesa profile. - Highlights: • Sb beam flux termination temperature is crucial for redundant Sb condensation. • Sb beam flux level has a role on the thickness of redundant condensed Sb layer. • Redundant Sb layer thickness can be measured by two-sloped mesa structure

  13. A comparison between placental and amniotic mesenchymal stem cells for transamniotic stem cell therapy (TRASCET) in experimental spina bifida.

    Science.gov (United States)

    Feng, Christina; D Graham, Christopher; Connors, John Patrick; Brazzo, Joseph; Zurakowski, David; Fauza, Dario O

    2016-06-01

    We compared placental-derived and amniotic fluid-derived mesenchymal stem cells (pMSCs and afMSCs, respectively) in transamniotic stem cell therapy (TRASCET) for experimental spina bifida. Pregnant dams (n=29) exposed to retinoic acid for the induction of fetal spina bifida were divided into four groups. Three groups received volume-matched intraamniotic injections of either saline (n=38 fetuses) or a suspension of 2×10(6) cells/mL of syngeneic, labeled afMSCs (n=73) or pMSCs (n=115) on gestational day 17 (term=21-22days). Untreated fetuses served as controls. Animals were killed before term. Statistical comparisons were by Fisher's exact test (pcell source for TRASCET as a potential alternative in the prenatal management of spina bifida. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Zr3NiSb7: a new antimony-enriched ZrSb2 derivative

    Directory of Open Access Journals (Sweden)

    V. Romaka

    2008-08-01

    Full Text Available Single crystals of trizirconium nickel heptaantimonide were synthesized from the constituent elements by arc-melting. The compound crystallizes in a unique structure type and belongs to the family of two-layer structures. All crystallographically unique atoms (3 × Zr, 1 × Ni and 7 × Sb are located at sites with m symmetry. The structure contains `Zr2Ni2Sb5' and `Zr4Sb9' fragments and might be described as a new ZrSb2 derivative with a high Sb content.

  15. Density functional simulations of Sb-rich GeSbTe phase change alloys

    OpenAIRE

    Gabardi, S; Caravati, S; Bernasconi, M; Parrinello, M

    2012-01-01

    We generated models of the amorphous phase of Sb rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge 1Sb 1Te 1 and Ge 2Sb 4Te 5. Comparison with previous results on the most studied Ge 2Sb 2Te 5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high fr...

  16. Dissimilatory Sb(V) reduction by microorganisms isolated from Sb-contaminated sediment

    Science.gov (United States)

    Dovick, M. A.; Kulp, T. R.

    2013-12-01

    Mining and smelting are major sources of trace metal contamination in freshwater systems. Arsenic (As) is a common contaminant derived from certain mining operations and is a known toxic metalloid and carcinogen. Antimony (Sb) is listed as a pollutant of priority interest by the EPA and is presumed to share similar geochemical and toxicological properties with arsenic. Both elements can occur in four different oxidation states (V, III, 0, and -III) under naturally occurring conditions. In aqueous solutions As(V) and Sb(V) predominate in oxygenated surface waters whereas As(III) and Sb(III) are stable in anoxic settings. Numerous studies have examined microbiological redox pathways that utilize As(V) as a terminal electron acceptor for anaerobic respiration, however there have been few studies on microbial mechanisms that may affect the biogeochemical cycling of Sb in the environment. Here we report bacterial reduction of Sb(V) to Sb(III) in anoxic enrichment cultures and bacterial isolates grown from sediment collected from an Sb contaminated pond at a mine tailings site in Idaho (total pond water Sb concentration = 235.2 +/- 136.3 ug/L). Anaerobic sediment microcosms (40 mL) were established in artificial freshwater mineral salt medium, amended with millimolar concentrations of Sb(V), acetate or lactate, and incubated at 27°C for several days. Antimony(V), lactate, and acetate concentrations were monitored during incubation by High Performance Liquid Chromatography (HPLC) and Ion Chromatography (IC). Live sediment microcosms reduced millimolar amendments of Sb(V) to Sb(III) coupled to the oxidation of acetate and lactate, while no activity occurred in killed controls. Enrichment cultures were established by serially diluting Sb(V)-reducing microcosms in mineral salt medium with Sb(V) and acetate, and a Sb(V)-reducing bacterial strain was isolated by plating on anaerobic agar plates amended with millimolar Sb(V) and acetate. Direct cell counting demonstrated that

  17. New superconductor LaRhSb

    International Nuclear Information System (INIS)

    Nishigori, S.; Moriwaki, H.; Suzuki, T.; Fujita, T.; Tanaka, H.; Takabatake, T.; Fujii, H.

    1994-01-01

    Superconductivity in LaRhSb was newly found below the transition temperature T c = 2.67 K by the measurements of the electrical resistivity, magnetic susceptibility and specific heat in magnetic fields. The characteristics of the superconductivity determined in this study indicate that LaRhSb is a type II superconductor following the BCS theory. (orig.)

  18. Density functional simulations of Sb-rich GeSbTe phase change alloys

    International Nuclear Information System (INIS)

    Gabardi, S; Bernasconi, M; Caravati, S; Parrinello, M

    2012-01-01

    We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge 1 Sb 1 Te 1 and Ge 2 Sb 4 Te 5 . Comparison with previous results on the most studied Ge 2 Sb 2 Te 5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm -1 are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge 2 Sb 2 Te 5 . All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

  19. Density functional simulations of Sb-rich GeSbTe phase change alloys

    Science.gov (United States)

    Gabardi, S.; Caravati, S.; Bernasconi, M.; Parrinello, M.

    2012-09-01

    We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge1Sb1Te1 and Ge2Sb4Te5. Comparison with previous results on the most studied Ge2Sb2Te5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm-1 are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge2Sb2Te5. All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

  20. High quality InAsSb grown on InP substrates using AlSb/AlAsSb buffer layers

    International Nuclear Information System (INIS)

    Wu, B.-R.; Liao, C.; Cheng, K. Y.

    2008-01-01

    High quality InAsSb grown on semi-insulating InP substrates by molecular beam epitaxy was achieved using AlSb/AlAsSb structure as the buffer layer. A 1000 A InAsSb layer grown on top of 1 μm AlSb/AlAsSb buffer layer showed a room temperature electron mobility of ∼12 000 cm 2 /V s. High structural quality and low misfit defect density were also demonstrated in the InAsSb layer. This novel AlSb/AlAsSb buffer layer structure with the AlAsSb layer lattice matched to InP substrates could enhance the performance of optoelectronic devices utilizing 6.1 A family of compound semiconductor alloys

  1. Paternal exposure to Agent Orange and spina bifida: a meta-analysis

    International Nuclear Information System (INIS)

    Ngo, Anh Duc; Taylor, Richard; Roberts, Christine L.

    2010-01-01

    The objective of this study is to conduct a meta-analysis of published and unpublished studies that examine the association between Agent Orange (AO) exposure and the risk of spina bifida. Relevant studies were identified through a computerized literature search of Medline and Embase from 1966 to 2008; a review of the reference list of retrieved articles and conference proceedings; and by contacting researchers for unpublished studies. Both fixed-effects and random-effects models were used to pool the results of individual studies. The Cochrane Q test and index of heterogeneity (I 2 ) were used to evaluate heterogeneity, and a funnel plot and Egger's test were used to evaluate publication bias. Seven studies, including two Vietnamese and five non-Vietnamese studies, involving 330 cases and 134,884 non-cases were included in the meta-analysis. The overall relative risk (RR) for spina bifida associated with paternal exposure to AO was 2.02 (95% confidence interval [CI]: 1.48-2.74), with no statistical evidence of heterogeneity across studies. Non-Vietnamese studies showed a slightly higher summary RR (RR = 2.22; 95% CI: 1.38-3.56) than Vietnamese studies (RR = 1.92 95% CI: 1.29-2.86). When analyzed separately, the overall association was statistically significant for the three case-control studies (Summary Odds Ratio = 2.25, 95% CI: 1.31-3.86) and the cross sectional study (RR = 1.97, 95% CI: 1.31-2.96), but not for the three cohort studies (RR: 2.11; 95% CI: 0.78-5.73). Paternal exposure to AO appears to be associated with a statistically increased risk of spina bifida.

  2. Neural Tube Defects: Epidemiologic Factors, Clinical Presentation ...

    African Journals Online (AJOL)

    Of the 103 babies, 87 (84.5%) had spina bifida cystica, 15 (14.6%) had occipital encephalocele, while 1 (0.9%) had anencephaly and died within 8 hours of delivery. All the 87 patients with spina bifida cystica were ruptured and infected at presentation, with seven of them dying from overwhelming sepsis. Most of the babies ...

  3. A unifying hypothesis for hydrocephalus, Chiari malformation, syringomyelia, anencephaly and spina bifida

    Directory of Open Access Journals (Sweden)

    Williams Helen

    2008-04-01

    Full Text Available Abstract This work is a modified version of the Casey Holter Memorial prize essay presented to the Society for Research into Hydrocephalus and Spina Bifida, June 29th 2007, Heidelberg, Germany. It describes the origin and consequences of the Chiari malformation, and proposes that hydrocephalus is caused by inadequate central nervous system (CNS venous drainage. A new hypothesis regarding the pathogenesis, anencephaly and spina bifida is described. Any volume increase in the central nervous system can increase venous pressure. This occurs because veins are compressible and a CNS volume increase may result in reduced venous blood flow. This has the potential to cause progressive increase in cerebrospinal fluid (CSF volume. Venous insufficiency may be caused by any disease that reduces space for venous volume. The flow of CSF has a beneficial effect on venous drainage. In health it moderates central nervous system pressure by moving between the head and spine. Conversely, obstruction to CSF flow causes localised pressure increases, which have an adverse effect on venous drainage. The Chiari malformation is associated with hindbrain herniation, which may be caused by low spinal pressure relative to cranial pressure. In these instances, there are hindbrain-related symptoms caused by cerebellar and brainstem compression. When spinal injury occurs as a result of a Chiari malformation, the primary pathology is posterior fossa hypoplasia, resulting in raised spinal pressure. The small posterior fossa prevents the flow of CSF from the spine to the head as blood enters the central nervous system during movement. Consequently, intermittent increases in spinal pressure caused by movement, result in injury to the spinal cord. It is proposed that posterior fossa hypoplasia, which has origins in fetal life, causes syringomyelia after birth and leads to damage to the spinal cord in spina bifida. It is proposed that hydrocephalus may occur as a result of

  4. Spina bifida and unilateral focal destruction of the distal femoral epiphysis

    Energy Technology Data Exchange (ETDEWEB)

    Wolverson, M.K.; Sundaram, M.; Graviss, E.R.

    1981-03-01

    Focal destruction of the postero-lateral distal femoral epiphysis was present on radiographs in two children with spina bifida and objective lower limb sensory loss. Each patient presented with painless swelling of the knee. In one patient the epiphysis showed sclerosis and fragmentation associated with a defect. In the second patient the destructive change was the dominant radiographic abnormality and simulated bone tumor. Computed tomography in this patient showed a bone fragment occupying the defect suggesting epiphyseal fracture. The lesions in each patient were believed to be traumatic in origin and to represent a stage in the development toward neuropathic arthropathy.

  5. Spina bifida and unilateral focal destruction of the distal femoral epiphysis

    International Nuclear Information System (INIS)

    Wolverson, M.K.; Sundaram, M.; Graviss, E.R.

    1981-01-01

    Focal destruction of the postero-lateral distal femoral epiphysis was present on radiographs in two children with spina bifida and objective lower limb sensory loss. Each patient presented with painless swelling of the knee. In one patient the epiphysis showed sclerosis and fragmentation associated with a defect. In the second patient the destructive change was the dominant radiographic abnormality and simulated bone tumor. Computed tomography in this patient showed a bone fragment occupying the defect suggesting epiphyseal fracture. The lesions in each patient was believed to be traumatic in origin and to represent a stage in the development toward neuropathic arthropathy. (orig.)

  6. Marjolin's ulcers: theories, prognostic factors and their peculiarities in spina bifida patients

    Directory of Open Access Journals (Sweden)

    Nthumba Peter M

    2010-12-01

    Full Text Available Abstract Background Due to improved care, more and more children born with spina bifida in rural Kenya are surviving into adulthood. This improved survival has led to significant challenges in their lifestyles, especially the need to ensure pressure ulcer prevention and treatment. Malignant degeneration of pressure ulcers in spina bifida patients is very rare. The author describes the clinical presentation of two pressure ulcer carcinomas that are at variance from classical descriptions. Materials and methods An internet/Medline/PubMed search of English literature for theories on Marjolin's ulcer evolution and prognostic features of Marjolin's ulcers was performed. A chart review of two young adults with spina bifida who had presented to the author's hospital between 2004 and August 2010 with chronic pressure ulcers found to be Marjolin's ulcers on histo-pathological examination was performed, and the clinical features are reported. Results The two ulcers appeared clinically benign: one was a deep ulcer, while the other was shallow; both had normal, benign-appearing edges, and a foul smelling discharge. The two ulcers were surrounded by induration and multiple communicating sinuses, with no evidence of chronic osteomyelitis. The internet search revealed a total of nine theories on Marjolin's ulcer development, as well as seven clinical and four histological prognostic features. Discussion The multifactorial theory, a coalescence of a number of proposed theories, best explains the evolution of Marjolin's ulcers. Poor prognostic features include pressure ulcer carcinomas, lesions and location in the lower limbs/trunks, all present in the two patients making their prognosis dim: this is despite the surgical margins being clear of tumor. Benign appearance, induration and presence of multiple communicating sinuses are features that have not been previously described as presenting features of pressure ulcers carcinomas. Conclusion There is need for

  7. Epidemiologic study of neural tube defects in Los Angeles County. I. Prevalence at birth based on multiple sources of case ascertainment

    Energy Technology Data Exchange (ETDEWEB)

    Sever, L.E. (Pacific Northwest Lab., Richland, WA); Sanders, M.; Monsen, R.

    1982-01-01

    Epidemiologic studies of the neural tube defects (NTDs), anencephalus and spina bifida, have for the most part been based on single sources of case ascertainment in past studies. The present investigation attempts total ascertainment of NTD cases in the newborn population of Los Angeles County residents for the period 1966 to 1972. Design of the study, sources of data, and estimates of prevalence rates based on single and multiple sources of case ascertainment are here discussed. Anencephalus cases totaled 448, spina bifida 442, and encephalocele 72, giving prevalence rates of 0.52, 0.51, and 0.08 per 1000 total births, respectively, for these neural tube defects - rates considered to be low. The Los Angeles County prevalence rates are compared with those of other recent North American studies and support is provided for earlier suggestions of low rates on the West Coast.

  8. Crystallographic study of the intermediate compounds SbZn, Sb3Zn4 and Sb2Zn3

    International Nuclear Information System (INIS)

    Adjadj, Fouzia; Belbacha, El-djemai; Bouharkat, Malek; Kerboub, Abdellah

    2006-01-01

    The processes of development of semiconductor ceramics made up of bismuth, antimony and zinc often require during their preparation to know the nature of the involved phases. For that, it is always essential to refer to the diagrams of balance between phases of the binary systems or ternary. We presented in this work the study by X-rays diffraction relating to the intermediate compounds SbZn, Sb 3 Zn 4 and Sb 2 Zn 3 . The analysis by X-rays is often useful to give supplement the results of the other experimental methods

  9. Birth Defects in Newborns: Spina Bifida Index at Rio Grande Do Norte State in Brazil

    Directory of Open Access Journals (Sweden)

    Arnaldo CM Junior

    2014-08-01

    Conclusion: Northeast region is the one that has the major incidence of SB in Brazil country, but RN state has a number lower than others states from its region. It was made an update about therapeutic options to minimize the morbidity and mortality in newborn with SB congenital defects. [J Interdiscipl Histopathol 2014; 2(4.000: 217-223

  10. Does folic acid use decrease the risk for spina bifida after in utero exposure to valproic acid?

    NARCIS (Netherlands)

    Jentink, J.; Bakker, M.K.; Nijenhuis, C.M.; Wilffert, B.; de Jong-van den Berg, L.T.W.

    Purpose Women with child wish are advised to take folic acid supplements to reduce the risk for spina bifida. However, there is less evidence for this protective effect in women using valproic acid (VPA). We investigated the effect of folic acid in women exposed to VPA in the first trimester of

  11. Arm cranking versus wheelchair propulsion for testing aerobic fitness in children with spina bifida who are wheelchair dependent

    NARCIS (Netherlands)

    Bloemen, Manon A T; De Groot, Janke F.; Backx, FJG; Westerveld, Rosalyne A.; Takken, Tim

    2015-01-01

    Objective: To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. Design: Validity and reliability study. Subjects: Young

  12. Arm cranking versus wheelchair propulsion for testing aerobic fitness in children with spina bifida who are wheelchair dependent.

    NARCIS (Netherlands)

    Bloemen, M.A.T.; Groot, J.F. de; Backx, F.J.G.; Westerveld, R.A.; Takken, T.

    2015-01-01

    OBJECTIVE: To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. DESIGN: Validity and reliability study. SUBJECTS: Young

  13. Thermodynamic stability studies of Ce-Sb compounds with Fe

    Science.gov (United States)

    Xie, Yi; Zhang, Jinsuo; Benson, Michael T.; Mariani, Robert D.

    2018-02-01

    Lanthanide fission products can migrate to the fuel periphery and react with cladding, causing fuel-cladding chemical interaction (FCCI). Adding a fuel additive dopant, such as Sb, can bind lanthanide, such as Ce, into metallic compounds and thus prevent migration. The present study focuses on the thermodynamic stability of Ce-Sb compounds when in contact with the major cladding constituent Fe by conducting diffusion couple tests. Ce-Sb compounds have shown high thermodynamic stability as they did not react with Fe. When Fe-Sb compounds contacted with Ce, Sb was separated out of Fe-Sb compounds and formed the more stable Ce-Sb compounds.

  14. 118 SNPs of folate-related genes and risks of spina bifida and conotruncal heart defects

    Directory of Open Access Journals (Sweden)

    Shaw Gary M

    2009-06-01

    Full Text Available Abstract Background Folic acid taken in early pregnancy reduces risks for delivering offspring with several congenital anomalies. The mechanism by which folic acid reduces risk is unknown. Investigations into genetic variation that influences transport and metabolism of folate will help fill this data gap. We focused on 118 SNPs involved in folate transport and metabolism. Methods Using data from a California population-based registry, we investigated whether risks of spina bifida or conotruncal heart defects were influenced by 118 single nucleotide polymorphisms (SNPs associated with the complex folate pathway. This case-control study included 259 infants with spina bifida and a random sample of 359 nonmalformed control infants born during 1983–86 or 1994–95. It also included 214 infants with conotruncal heart defects born during 1983–86. Infant genotyping was performed blinded to case or control status using a designed SNPlex assay. We examined single SNP effects for each of the 118 SNPs, as well as haplotypes, for each of the two outcomes. Results Few odds ratios (ORs revealed sizable departures from 1.0. With respect to spina bifida, we observed ORs with 95% confidence intervals that did not include 1.0 for the following SNPs (heterozygous or homozygous relative to the reference genotype: BHMT (rs3733890 OR = 1.8 (1.1–3.1, CBS (rs2851391 OR = 2.0 (1.2–3.1; CBS (rs234713 OR = 2.9 (1.3–6.7; MTHFD1 (rs2236224 OR = 1.7 (1.1–2.7; MTHFD1 (hcv11462908 OR = 0.2 (0–0.9; MTHFD2 (rs702465 OR = 0.6 (0.4–0.9; MTHFD2 (rs7571842 OR = 0.6 (0.4–0.9; MTHFR (rs1801133 OR = 2.0 (1.2–3.1; MTRR (rs162036 OR = 3.0 (1.5–5.9; MTRR (rs10380 OR = 3.4 (1.6–7.1; MTRR (rs1801394 OR = 0.7 (0.5–0.9; MTRR (rs9332 OR = 2.7 (1.3–5.3; TYMS (rs2847149 OR = 2.2 (1.4–3.5; TYMS (rs1001761 OR = 2.4 (1.5–3.8; and TYMS (rs502396 OR = 2.1 (1.3–3.3. However, multiple SNPs observed for a given gene showed evidence of linkage disequilibrium indicating

  15. Defect Structure of High-Temperature-Grown GaMnSb/GaSb

    International Nuclear Information System (INIS)

    Romanowski, P.; Bak-Misiuk, J.; Dynowska, E.; Domagala, J.Z.; Wojciechowski, T.; Jakiela, R.; Sadowski, J.; Barcz, A.; Caliebe, W.

    2010-01-01

    GaMnSb/GaSb(100) layers with embedded MnSb inclusions have been grown at 720 K using MBE technique. This paper presents the investigation of the defect structure of Ga1-xMnxSb layers with different content of manganese (up to x = 0.07). X-ray diffraction method using conventional and synchrotron radiation was applied. Dimensions and shapes of inclusions were detected by scanning electron microscopy. Depth profiles of elements were measured using secondary ion mass spectroscopy technique. (authors)

  16. Structural and Electronic Features of Sb-Based Electrode Materials: 121Sb Moessbauer Spectrometry

    International Nuclear Information System (INIS)

    Ionica, C. M.; Aldon, L.; Lippens, P. E.; Morato, F.; Olivier-Fourcade, J.; Jumas, J.-C.

    2004-01-01

    Lithium insertion mechanisms in two antimony based compounds: CoSb 3 and CoSb have been studied by means of 121 Sb Moessbauer spectrometry. Structural and electronic modifications induced by insertion of lithium have been characterised for different depths of discharge. In all cases the insertion mechanisms can be described from several steps. In the first step antimony is partially dispersed in the metallic matrix with amorphisation of the electrode material and in a second step we can observe the alloy forming (Li 3 Sb). However this amorphous alloy remains in interaction with the matrix allowing then a good reversibility.

  17. Tetrahedral 1B4Sb nanoclusters in GaP:(B, Sb)

    Energy Technology Data Exchange (ETDEWEB)

    Elyukhin, V A, E-mail: elyukhin@cinvestav.m [Departamento de Ingenieria Electrica-SEES, CINVESTAV-IPN, Avenida IPN 2508, Col. San Pedro Zacatenco, C. P. 07360, Mexico, D. F. (Mexico)

    2009-05-01

    Self-assembling conditions of 1B4Sb tetrahedral nanoclusters in GaP doped with boron and Sb isoelectronic impurities are represented in the ultradilute and dilute limits of the boron and Sb contents, respectively. The fulfilled estimates demonstrated the preferential complete or almost complete allocation of boron atoms in 1B4Sb nanoclusters at temperatures of 500 {sup 0}C and 900 {sup 0}C, respectively. The significant decrease of the sum of the free energies of the constituent compounds is the main origin of self-assembling. The reduction of the strain energy is the additional cause of this phenomenon.

  18. Prenatal diagnosis of parapagus diprosopus dibrachius dipus twins with spina bifida in the first trimester using two- and three-dimensional ultrasound

    OpenAIRE

    Pei-Yin Yang; Ching-Hua Wu; Guang-Perng Yeh; Charles Tsung-Che Hsieh

    2015-01-01

    Objective: Here, we report a case of parapagus diprosopus twins with spina bifida diagnosed in the first trimester of pregnancy using two-dimensional (2D) and three-dimensional (3D) ultrasound. Case report: A 28-year-old Taiwanese woman, gravid 1, para 0, visited our hospital due to an abnormal fetal head shape discovered by 2D ultrasound at 11-weeks gestation. Parapagus diprosopus twins with spina bifida were diagnosed after ultrasound examination. The characteristics of parapagus diproso...

  19. Decay of /sup 125/Sb

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K; Sahota, H S

    1983-01-01

    The 2.7 yr beta decay of /sup 125/Sb yields /sup 125/Te has been studied using Ge(Li), Si(Li) and Ge detectors and the directional correlation technique New lines at 58, 111, 642, 693 and 729 keV have been detected and fitted in the decay scheme in the already existing levels, besides the one suggested at 729 keV. The intensities of 20, 109, 111, 116, 172, 178 and 198 keV transitions have been measured more precisely than before. The ..gamma..-..gamma.. directional correlation measurements in the 208-463, 204-176 and 321-176 keV cascades have enabled to assign a uniquue spin 7/2/sup -/ to the 525 keV level. The multipole mixing ratios for the 204, 208 and 321 keV transitions have been found as M1 + (14.75 +- 3.55)%E2, M1 + (4.5 +- 2.0)%E2 and E1 + (2.70 +- 0.75)%M2, respectively.

  20. Epidemiological causality.

    Science.gov (United States)

    Morabia, Alfredo

    2005-01-01

    Epidemiological methods, which combine population thinking and group comparisons, can primarily identify causes of disease in populations. There is therefore a tension between our intuitive notion of a cause, which we want to be deterministic and invariant at the individual level, and the epidemiological notion of causes, which are invariant only at the population level. Epidemiologists have given heretofore a pragmatic solution to this tension. Causal inference in epidemiology consists in checking the logical coherence of a causality statement and determining whether what has been found grossly contradicts what we think we already know: how strong is the association? Is there a dose-response relationship? Does the cause precede the effect? Is the effect biologically plausible? Etc. This approach to causal inference can be traced back to the English philosophers David Hume and John Stuart Mill. On the other hand, the mode of establishing causality, devised by Jakob Henle and Robert Koch, which has been fruitful in bacteriology, requires that in every instance the effect invariably follows the cause (e.g., inoculation of Koch bacillus and tuberculosis). This is incompatible with epidemiological causality which has to deal with probabilistic effects (e.g., smoking and lung cancer), and is therefore invariant only for the population.

  1. The equilibrium diagram and some properties of alloys Gd5Sb3-Tb5Sb3 system

    International Nuclear Information System (INIS)

    Azizov, Yu.S.; Abulkhaev, V.D.; Ganiev, I.N.

    2001-01-01

    The purpose of present work is investigation equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system in total range of concentrations. Equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system investigated by methods of difference-thermal, roentgen-phase and metallographic analyses. For the first time on the base of difference-thermal, roentgen-phase and metallographic analyses was formed the equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system. Was determined the cristal-chemical parameters of solid solutions with general formula Gd x Tb 5 - x Sb 3

  2. Si-Sb-Te materials for phase change memory applications

    International Nuclear Information System (INIS)

    Rao Feng; Song Zhitang; Ren Kun; Zhou Xilin; Cheng Yan; Wu Liangcai; Liu Bo

    2011-01-01

    Si-Sb-Te materials including Te-rich Si 2 Sb 2 Te 6 and Si x Sb 2 Te 3 with different Si contents have been systemically studied with the aim of finding the most suitable Si-Sb-Te composition for phase change random access memory (PCRAM) use. Si x Sb 2 Te 3 shows better thermal stability than Ge 2 Sb 2 Te 5 or Si 2 Sb 2 Te 6 in that Si x Sb 2 Te 3 does not have serious Te separation under high annealing temperature. As Si content increases, the data retention ability of Si x Sb 2 Te 3 improves. The 10 years retention temperature for Si 3 Sb 2 Te 3 film is ∼ 393 K, which meets the long-term data storage requirements of automotive electronics. In addition, Si richer Si x Sb 2 Te 3 films also show improvement on thickness change upon annealing and adhesion on SiO 2 substrate compared to those of Ge 2 Sb 2 Te 5 or Si 2 Sb 2 Te 6 films. However, the electrical performance of PCRAM cells based on Si x Sb 2 Te 3 films with x > 3.5 becomes worse in terms of stable and long-term operations. Si x Sb 2 Te 3 materials with 3 < x < 3.5 are proved to be suitable for PCRAM use to ensure good overall performance.

  3. InSb semiconductors and (In,Mn)Sb diluted magnetic semiconductors. Growth and properties

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Lien

    2011-04-13

    This dissertation describes investigations of the growth by molecular beam epitaxy and the characterization of the semiconductor InSb as well as the diluted magnetic semiconductor (DMS) In{sub 1-x}Mn{sub x}Sb. The InSb films were grown on GaAs (001) substrate and Si (001) offcut by 4 toward (110) substrate up to a thickness of about 2 {mu}m, in spite of a large lattice mismatch between the epi-layer and substrate (14.6% between InSb and GaAs, and 19.3% between InSb and Si). After optimizing the growth conditions, the best InSb films grown directly on GaAs without any special technique results in a high crystal quality, low noise, and an electron mobility of 41100 cm{sup 2}/V s Vs with associated electron concentration of 2.9.10{sup 6} cm{sup -3} at 300 K. Such structures could be used, for example, for infrared detector structures. The growth of InSb on Si, however, is a challenge. In order to successfully grow InSb on Si, tilted substrates and the insertion of buffer layers were used, which helps to reduce the lattice mismatch as well as the formation of defects, and hence to improve the crystal quality. An electron mobility of 24000 cm{sup 2}/V s measured at 300 K, with an associated carrier concentration of 2.6.10{sup 1}6 cm{sup -3} is found for the best sample that was grown at 340 C with a 0.06 {mu}m-thick GaSb/AlSb superlattice buffer layer. The smaller value of electron mobility (compared to the best GaAsbased sample) is related to a higher density of microtwins and stacking faults as well as threading dislocations in the near-interface region as shown by transmission electron microscopy. Deep level noise spectra indicate the existence of deep levels in both GaAs and Si-based samples. The samples grown on Si exhibit the lowest Hooge factor at 300 K, lower than the samples grown on GaAs. Taking the optimized growth conditions of InSb/GaAs, the diluted magnetic semiconductor In{sub 1-x}Mn{sub x}Sb/GaAs (001) is prepared by adding a few percent of Mn into the

  4. Polarity-dependent resistance switching in GeSbTe phase-change thin films : The importance of excess Sb in filament formation

    NARCIS (Netherlands)

    Pandian, Ramanathaswamy; Kooi, Bart J.; Oosthoek, Jasper L. M.; van den Dool, Pim; Palasantzas, George; Pauza, Andrew

    2009-01-01

    We show that polarity-dependent resistance switching in GeSbTe thin films depends strongly on Sb composition by comparing current-voltage characteristics in Sb-excess Ge(2)Sb(2+x)Te(5) and stoichiometric Ge(2)Sb(2)Te(5) samples. This type of switching in Ge(2)Sb(2+x)Te(5) films is reversible with

  5. Altered expression of 14-3-3ζ protein in spinal cords of rat fetuses with spina bifida aperta.

    Directory of Open Access Journals (Sweden)

    Li-na Wu

    Full Text Available BACKGROUND: A large number of studies have confirmed that excessive apoptosis is one of the reasons for deficient neuronal function in neural tube defects (NTDs. A previous study from our laboratory used 2-D gel electrophoresis to demonstrate that 14-3-3ζ expression was low in the spinal cords of rat fetuses with spina bifida aperta at embryonic day (E 17. As a member of the 14-3-3 protein family, 14-3-3ζ plays a crucial role in the determination of cell fate and anti-apoptotic activity. However, neither the expression of 14-3-3ζ in defective spinal cords, nor the correlation between 14-3-3ζ and excessive apoptosis in NTDs has been fully confirmed. METHODOLOGY/PRINCIPAL FINDINGS: We used immunoblotting and quantitative real-time PCR (qRT-PCR to quantify the expression of 14-3-3ζ and double immunofluorescence to visualize 14-3-3ζ and apoptosis. We found that, compared with controls, 14-3-3ζ was down-regulated in spina bifida between E12 and E15. Excessive apoptotic cells and low expression of 14-3-3ζ were observed in the dorsal region of spinal cords with spina bifida during the same time period. To initially explore the molecular mechanisms of apoptosis in NTDs, we investigated the expression of microRNA-7 (miR-7, microRNA-375 (miR-375 and microRNA-451 (miR-451, which are known to down-regulate 14-3-3ζ in several different cell types. We also investigated the expression of p53, a molecule that is downstream of 14-3-3ζ and can be down-regulated by it. We discovered that, in contrast to the reduction of 14-3-3ζ expression, the expression of miR-451, miR-375 and p53 increased in spina bifida rat fetuses. CONCLUSIONS/SIGNIFICANCE: These data suggest that the reduced expression of 14-3-3ζ plays a role in the excessive apoptosis that occurs in spina bifida and may be partly regulated by the over-expression of miR-451 and miR-375, and the consequent up-regulation of p53 might further promote apoptosis in spina bifida.

  6. DWPF simulant CPC studies for SB8

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, D. C.; Zamecnik, J. R.

    2013-06-25

    The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain the Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing

  7. DWPF simulant CPC studies for SB8

    International Nuclear Information System (INIS)

    Koopman, D. C.; Zamecnik, J. R.

    2013-01-01

    The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain the Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing

  8. [Association of intercalary cervical bone and occult lumbar and sacral spina bifida. Case report].

    Science.gov (United States)

    Ruiz-Osuna, César; Avila-Zamorano, Myrna Lizeth; Suárez-Ahedo, Carlos; Trueba-Davalillo, Cesáreo

    2009-01-01

    The defects of the spinal cord enclose diverse malformations that go from spina bifida to myelomeningocele but there is also a rare variant that is the intercalary bone. The incidence of this phenomenon may vary in 1 to 1,000 to 5,000. At our knowledge, there are no cases reported where it can be an association of intercalary bone and a bifid spine in different levels. In this article we report the case of one patient that coincide with an intercalary cervical bone, bifid spine in lumbar column and bifid spine in sacral column. The objective of this article is also to comment how the clinical symptoms are unspecific, the chronic pain is the frequent symptom, and how the physiotherapy and anti-inflammatory drugs can provide excellent results in a short and medium term.

  9. Sonographic detection of open spina bifida in the first trimester: review of the literature.

    Science.gov (United States)

    Meller, César; Aiello, Horacio; Otaño, Lucas

    2017-07-01

    In the beginnings, sonographic diagnosis of open spina bifida (OSB) relied on the meticulous scanning of the fetal vertebrae for abnormalities but many defects were missed. After the mid-1980s, however, with the description of the intracranial findings in the second trimester (the "lemon sign" and the "banana sign"), the prenatal diagnosis of OSB was enhanced. In the last 2 decades, there has been widespread uptake of routine ultrasound examination in the first trimester of pregnancy with the purpose of the measurement of fetal crown-rump length to determine gestational age, to screen for trisomy 21 and other aneuploidies, mainly with the nuchal translucency, and for diagnosis of many major abnormalities. Many papers were published focusing on early diagnosis of myelomeningocele (MMC), and the objective of this review is to summarize the different techniques described regarding prenatal diagnosis of OSB in the first trimester of pregnancy.

  10. Assessing the prevalence of spina bifida and encephalocele in a Kenyan hospital from 2005–2010: implications for a neural tube defects surveillance system

    Science.gov (United States)

    Githuku, Jane N; Azofeifa, Alejandro; Valencia, Diana; Ao, Trong; Hamner, Heather; Amwayi, Samuel; Gura, Zeinab; Omolo, Jared; Albright, Leland; Guo, Jing; Arvelo, Wences

    2014-01-01

    Introduction Neural tube defects such as anencephaly, spina bifida, and encephalocele are congenital anomalies of the central nervous system. Data on the prevalence of neural tube defects in Kenya are limited. This study characterizes and estimates the prevalence of spina bifida and encephalocele reported in a referral hospital in Kenya from 2005-2010. Methods Cases were defined as a diagnosis of spina bifida or encephalocele. Prevalence was calculated as the number of cases by year and province of residence divided by the total number of live-births per province. Results From a total of 6,041 surgical records; 1,184 (93%) had reported diagnosis of spina bifida and 88 (7%) of encephalocele. Estimated prevalence of spina bifida and encephalocele from 2005-2010 was 3.3 [95% Confidence Interval (CI): 3.1-3.5] cases per 10,000 live-births. The highest prevalence of cases were reported in 2007 with 4.4 (95% CI: 3.9-5.0) cases per 10,000 live-births. Rift Valley province had the highest prevalence of spina bifida and encephalocele at 6.9 (95% CI: 6.3-7.5) cases per 10,000 live-births from 2005-2010. Conclusion Prevalence of spina bifida and encephalocele is likely underestimated, as only patients seeking care at the hospital were included. Variations in regional prevalence could be due to referral patterns and healthcare access. Implementation of a neural tube defects surveillance system would provide a more thorough assessment of the burden of neural tube defects in Kenya. PMID:26113894

  11. Assessing the prevalence of spina bifida and encephalocele in a Kenyan hospital from 2005-2010: implications for a neural tube defects surveillance system.

    Science.gov (United States)

    Githuku, Jane N; Azofeifa, Alejandro; Valencia, Diana; Ao, Trong; Hamner, Heather; Amwayi, Samuel; Gura, Zeinab; Omolo, Jared; Albright, Leland; Guo, Jing; Arvelo, Wences

    2014-01-01

    Neural tube defects such as anencephaly, spina bifida, and encephalocele are congenital anomalies of the central nervous system. Data on the prevalence of neural tube defects in Kenya are limited. This study characterizes and estimates the prevalence of spina bifida and encephalocele reported in a referral hospital in Kenya from 2005-2010. Cases were defined as a diagnosis of spina bifida or encephalocele. Prevalence was calculated as the number of cases by year and province of residence divided by the total number of live-births per province. From a total of 6,041 surgical records; 1,184 (93%) had reported diagnosis of spina bifida and 88 (7%) of encephalocele. Estimated prevalence of spina bifida and encephalocele from 2005-2010 was 3.3 [95% Confidence Interval (CI): 3.1-3.5] cases per 10,000 live-births. The highest prevalence of cases were reported in 2007 with 4.4 (95% CI: 3.9-5.0) cases per 10,000 live-births. Rift Valley province had the highest prevalence of spina bifida and encephalocele at 6.9 (95% CI: 6.3-7.5) cases per 10,000 live-births from 2005-2010. Prevalence of spina bifida and encephalocele is likely underestimated, as only patients seeking care at the hospital were included. Variations in regional prevalence could be due to referral patterns and healthcare access. Implementation of a neural tube defects surveillance system would provide a more thorough assessment of the burden of neural tube defects in Kenya.

  12. “I Like to Play with My Friends”: Children with Spina Bifida and Belonging in Uganda

    Directory of Open Access Journals (Sweden)

    Femke Bannink

    2016-06-01

    Full Text Available This paper describes experiences of living and belonging from the perspectives of Ugandan children with spina bifida and their siblings and parents. We explored belonging at micro, meso and macro level taking into consideration African Childhood Disability Studies, central concepts of family, cultural conceptions of disability, poverty, and the notion of ‘ubuntu’, and using child-friendly culturally adjusted interview methods including play. Whilst children with spina bifida had a strong sense of belonging at household level, they experienced more difficulties engaging in larger social networks, including school. Poverty and stigma were important barriers to inclusion. We propose strengthening the network at family level, where the environment is more enabling for the children to find a place of belonging and support, and expanding investment and awareness at community and national level.

  13. Reduction in thermal conductivity of BiSbTe lump

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Kaleem [King Saud University, Sustainable Energy Technologies Center, College of Engineering, PO Box 800, Riyadh (Saudi Arabia); Wan, C. [Tsinghua University, State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Beijing (China); Al-Eshaikh, M.A.; Kadachi, A.N. [King Saud University, Research Center, College of Engineering, PO Box 800, Riyadh (Saudi Arabia)

    2017-03-15

    In this work, systematic investigations on the thermal conductivities of BiSbTe lump, microstructured pristine BiSbTe bulk and single wall carbon nanotubes (SWCNTs)/BiSbTe bulk nanocomposites were performed. BiSbTe lumps were crushed to form a coarse powder (200 μm) and effect of particle size reduction on the effective thermal conductivity of BiSbTe (200 μm) bulk were analyzed. For further reduction in the conductivity, a two pronged strategy has been employed. First, additional refinement of BiSbTe (200 μm) were performed through ball milling in an inert environment. Second, SWCNTs in 0.75, and 1.0 vol% were distributed uniformly in the fine BiSbTe ball milled powder. The results showed that the effective thermal conductivities decrease with the reduction in the particle size from lump to BiSbTe (200 μm) bulk as well as with the addition of SWCNTs accompanied by further refinement of BiSbTe particles. The significant reduction in thermal conductivities of the lump was achieved for pure BiSbTe (200 μm) bulk and 0.75 vol% of SWCNTs/BiSbTe composite. This can be ascribed to the enhanced phonon scattering by the grain boundaries between the nanostructured BiSbTe particles as well as the interfaces between BiSbTe and the low dimensional carbon nanotubes. (orig.)

  14. Sb(V reactivity with human blood components: redox effects.

    Directory of Open Access Journals (Sweden)

    Silvana López

    Full Text Available We assessed the reactivity of Sb(V in human blood. Sb(V reactivity was determined using an HPLC-HG-AFS hyphenated system. Sb(V was partially reduced to Sb(III in blood incubation experiments; however, Sb(III was a highly unstable species. The addition of 0.1 mol L(-1 EDTA prevented Sb(III oxidation, thus enabling the detection of the reduction of Sb(V to Sb(III. The transformation of Sb(V to Sb(III in human whole blood was assessed because the reduction of Sb(V in human blood may likely generate redox side effects. Our results indicate that glutathione was the reducing agent in this reaction and that Sb(V significantly decreased the GSH/GSSG ratio from 0.32 ± 0.09 to 0.07 ± 0.03. Moreover, the presence of 200 ng mL(-1 of Sb(V increased the activity of superoxide dismutase from 4.4 ± 0.1 to 7.0 ± 0.4 U mL(-1 and decreased the activity of glutathione peroxidase from 62 ± 1 to 34 ± 2 nmol min(-1 mL(-1.

  15. Compositional and structural characterisation of GaSb and GaInSb

    International Nuclear Information System (INIS)

    Corregidor, V.; Alves, E.; Alves, L.C.; Barradas, N.P.; Duffar, Th.; Franco, N.; Marques, C.; Mitric, A.

    2005-01-01

    Low band gap III-V semiconductors are researched for applications in thermophotovoltaic technology. GaSb crystal is often used as a substrate. Ga 1-x In x Sb is also a promising substrate material, because its lattice parameters can be adjusted by controlling x. We used a new method to synthesise GaSb and GaInSb, in which a high frequency alternate magnetic field is used to heat, to melt and to mix the elements. We present a compositional and structural characterisation of the materials using a combination of complementary techniques. Rutherford backscattering was used to determine accurately the composition of the GaSb. With proton induced X-ray emission in conjunction with a 3 x 3 μm 2 micro-beam we studied the homogeneity of the samples. Structural analysis and phase identification were done with X-ray diffraction. The results for GaSb show a homogeneous composition while the GaInSb samples were found to be strongly heterogeneous at the end of the ingot. The ingots produced are competitive feed material, when compared to other growth techniques, to be used in a second step for the production of good quality ternary crystals

  16. The Fermi surface of CeSb

    International Nuclear Information System (INIS)

    Crabtree, G.W.; Aoki, H.; Joss, W.; Hulliger, F.

    1987-01-01

    This paper uses accurate Fermi surface measurements as a test of hybridization models in CeSb. Detailed measurements of the Fermi surface geometry and effective masses are presented which show a number of unusual properties associated with the magnetic structure and anisotropy. Measurements are compared with predictions of a band structure in which the f-electron is assumed to be local, interacting with the conduction electrons only through anisotropic Coulomb and exchange interactions. This model reproduces all the unusual features observed in the measurements and suggests that hybridization is not essential to describing the electronic properties of CeSb

  17. Binuclear model of an Sb-galaxy

    International Nuclear Information System (INIS)

    Nezhinskij, E.M.

    1980-01-01

    To explain the causes of origin of the observed peculiarities of SB-galaxies a self-consistent stable model of an Sb-galaxy is constructed. The evolutionary scheme of origin of this model is described. The model consists of an extensive spherical corona, of two point nuclei and of a cloud of particles of infinitely small mass, the latter being bar-shaped and situated in the neighbourhood of the nuclei. The model has the following properties: the nuclei move along the circular orbit, whose centre coincides with that of the corona; the motion of the particles of the bar-shaped cloud is stable in the sense of Hill [ru

  18. Quadrupole interaction studies of Hg in Sb

    International Nuclear Information System (INIS)

    Soares, J.C.; Krien, K.; Herzog, P.; Folle, H.R.; Freitag, K.; Reuschenbach, F.; Reuschenbach, M.; Trzcinski, R.

    1978-01-01

    Time differential perturbed angular correlation and nuclear orientation studies of the electric quadrupole interaction for Hg in Sb have been performed. The effective field gradients at room temperature and below 0.05K have been derived. These two values are no indication for an anomalous temperature dependence of the effective field gradient for Hg in Sb. The value of the electric field gradient fits well into the systematics for Hg in other hosts. It is shown that the electronic enhancements of the field gradients are correlated to the valence of the impurities and are rather insensitive to the host properties. (orig./HPOE) [de

  19. 121Sb-NMR study of filled skutterudite CeOs4Sb12

    International Nuclear Information System (INIS)

    Yogi, M.; Niki, H.; Mukuda, H.; Kitaoka, Y.; Sugawara, H.; Sato, H.

    2007-01-01

    121 Sb nuclear magnetic resonance (NMR) of filled skutterudite compound CeOs 4 Sb 12 has been carried out to investigate a spin fluctuation below T∼25K. In spite of a powdered sample, many sharp peaks, similar to a data for single crystal, were observed because of an orientation of the sample from the anisotropy of the magnetization. A numerical calculation well reproduces resonance fields for Sb(1) sites with H parallel V zz . The nuclear spin-lattice relaxation rate divided by temperature 1/T 1 T shows continuous decrease with increasing magnetic field, indicating a suppression of the spin fluctuation by the field

  20. Spina bifida and cleft lip among newborns of Norwegian women with epilepsy: changes related to the use of anticonvulsants.

    Science.gov (United States)

    King, P B; Lie, R T; Irgens, L M

    1996-01-01

    OBJECTIVES: This study examined the connection between the use of anticonvulsants for epilepsy during or before pregnancy and the risk of spina bifida and cleft lip in newborns. METHODS: Among mothers registered from 1967 to 1992 by the Medical Birth Registry of Norway, 7588 who had epilepsy were identified and their newborns' prevalence of spina bifida and cleft lip examined. RESULTS: The odds ratio of spina bifida in children of mothers with epilepsy compared with other children increased from 1.5 in 1967 through 1980 (95% confidence interval [CI] = 0.3, 4.5) to 4.4 in 1981 through 1992 (95% CI = 2.0, 8.5). The odds ratio of cleft lip, however, decreased from 3.0 before 1981 (95% CI = 1.6, 5.1) to 1.1 after 1981 (95% CI = 0.4, 2.3). CONCLUSIONS: This shift toward more serious birth defects is consistent with the different teratogenic effects of newer and older anticonvulsants. PMID:8876519

  1. Arm cranking versus wheelchair propulsion for testing aerobic fitness in children with spina bifida who are wheelchair dependent.

    Science.gov (United States)

    Bloemen, Manon A T; de Groot, Janke F; Backx, Frank J G; Westerveld, Rosalyne A; Takken, Tim

    2015-05-01

    To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. Validity and reliability study. Young people with spina bifida who use a wheelchair. Physiological responses were measured during a Graded Arm Cranking Test and a Graded Wheelchair Propulsion Test using a heart rate monitor and calibrated mobile gas analysis system (Cortex Metamax). For validity, peak oxygen uptake (VO2peak) and peak heart rate (HRpeak) were compared using paired t-tests. For reliability, the intra-class correlation coefficients, standard error of measurement, and standard detectable change were calculated. VO2peak and HRpeak were higher during wheelchair propulsion compared with arm cranking (23.1 vs 19.5 ml/kg/min, p = 0.11; 165 vs 150 beats/min, p propulsion showed high intra-class correlation coefficients (ICCs) for both VO2peak (ICC = 0.93) and HRpeak (ICC = 0.90). This pilot study shows higher HRpeak and a tendency to higher VO2peak in young people with spina bifida who are using a wheelchair when tested during wheelchair propulsion compared with arm cranking. Wheelchair propulsion showed good reliability. We recommend performing a wheelchair propulsion test for aerobic fitness testing in this population.

  2. InSb semiconductors and (In,Mn)Sb diluted magnetic semiconductors: Growth and properties

    International Nuclear Information System (INIS)

    Tran, Lien

    2011-01-01

    This dissertation describes investigations of the growth by molecular beam epitaxy and the characterization of the semiconductor InSb as well as the diluted magnetic semiconductor (DMS) In 1-x Mn x Sb. The InSb films were grown on GaAs (001) substrate and Si (001) offcut by 4 toward (110) substrate up to a thickness of about 2 μm, in spite of a large lattice mismatch between the epi-layer and substrate (14.6% between InSb and GaAs, and 19.3% between InSb and Si). After optimizing the growth conditions, the best InSb films grown directly on GaAs without any special technique results in a high crystal quality, low noise, and an electron mobility of 41100 cm 2 /V s Vs with associated electron concentration of 2.9.10 6 cm -3 at 300 K. Such structures could be used, for example, for infrared detector structures. The growth of InSb on Si, however, is a challenge. In order to successfully grow InSb on Si, tilted substrates and the insertion of buffer layers were used, which helps to reduce the lattice mismatch as well as the formation of defects, and hence to improve the crystal quality. An electron mobility of 24000 cm 2 /V s measured at 300 K, with an associated carrier concentration of 2.6.10 1 6 cm -3 is found for the best sample that was grown at 340 C with a 0.06 μm-thick GaSb/AlSb superlattice buffer layer. The smaller value of electron mobility (compared to the best GaAsbased sample) is related to a higher density of microtwins and stacking faults as well as threading dislocations in the near-interface region as shown by transmission electron microscopy. Deep level noise spectra indicate the existence of deep levels in both GaAs and Si-based samples. The samples grown on Si exhibit the lowest Hooge factor at 300 K, lower than the samples grown on GaAs. Taking the optimized growth conditions of InSb/GaAs, the diluted magnetic semiconductor In 1-x Mn x Sb/GaAs (001) is prepared by adding a few percent of Mn into the host material InSb during growth. I have

  3. Peculiarities in cases of spina bifida cystica managed recently in south-east Nigeria: could antimalarial drugs be a major but unrecognized etiologic factor?

    Science.gov (United States)

    Emejulu, Jude-Kennedy C; Okwaraoha, Blaise Ogedi

    2011-01-01

    Spina bifida is a long-known disease arising from the incomplete fusion of the caudal neuropore in the first month of intrauterine life. It is thought to have a multifactorial etiology, the most important of which is folic acid deficiency. In evaluating its etiology, the role of antifolate agents like antimalarial drugs is rarely given a strong mention. This is a 44-month prospective study of consecutive cases of spina bifida cystica presenting to the Neurosurgery Unit of Nnamdi Azikiwe University Teaching Hospital, Nnewi, South-East Nigeria. Data collection was with a structured proforma from presentation, and collation done with Microsoft Excel broadsheet and data analysis with SPSS and χ2 test. A total of 41 cases of spina bifida were attended to within the period, with 92.7% cases of spina bifida cystica. Most presented by >12-24 months, with a consistent history of maternal ingestion of antimalarial drugs during the first trimester of pregnancy. Spina bifida cystica was diagnosed mostly in children whose mothers ingested antimalarial drugs during the first trimester of gestation. There may be a need to critically evaluate the contribution of antimalarial drugs to the etiopathogenesis of this malformation and develop safer antimalarial treatment in pregnancy. Copyright © 2012 S. Karger AG, Basel.

  4. Sulfuric Acid Corrosion of Low Sb - Pb Battery Alloys | Ntukogu ...

    African Journals Online (AJOL)

    The corrosion properties of low Sb - Pb alloys developed for maintenance free motive power industrial batteries was studied by a bare grid constant current method and compared to those of the conventional Pb- 6% Sb alloy. Low Sb-Pb alloys with Se and As grain refiners were found to have higher corrosion rates than the ...

  5. SULFURIC ACID CORROSION OF LOW Sb - Pb BATTERY ALLOYS

    African Journals Online (AJOL)

    user

    1983-09-01

    Sep 1, 1983 ... (Manuscript received February,1983). ABSTRACT. The corrosion properties of low Sb - Pb alloys developed for maintenance free motive power industrial batteries was studied by a bare grid constant current method and compared to those of the conventional. Pb- 6% Sb alloy. Low Sb-Pb alloys with Se and ...

  6. Building Planner Commitment : Are California's SB 375 and Oregon's SB 1059 Models for Climate-Change Mitigation?

    Science.gov (United States)

    2017-11-01

    California's Sustainable Communities and Climate Protection Act (SB 375) and the Oregon Sustainable Transportation Initiative (SB 1059) have made them the first states in the nation to try and reduce greenhouse gas (GHG) emissions using the transport...

  7. Recovering Parameters of Johnson's SB Distribution

    Science.gov (United States)

    Bernard R. Parresol

    2003-01-01

    A new parameter recovery model for Johnson's SB distribution is developed. This latest alternative approach permits recovery of the range and both shape parameters. Previous models recovered only the two shape parameters. Also, a simple procedure for estimating the distribution minimum from sample values is presented. The new methodology...

  8. Electroluminescence in p-InAs/AlSb/InAsSb/AlSb/p(n)-GaSb type II heterostructures with deep quantum wells at the interface

    Czech Academy of Sciences Publication Activity Database

    Mikhailova, M. P.; Ivanov, E.V.; Moiseev, K. D.; Yakovlev, Yu. P.; Hulicius, Eduard; Hospodková, Alice; Pangrác, Jiří; Šimeček, Tomislav

    2010-01-01

    Roč. 44, č. 1 (2010), 66-71 ISSN 1063-7826 Institutional research plan: CEZ:AV0Z10100521 Keywords : electroluninescence * MOVPE * GaSb * InAs * quantum well Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.603, year: 2010

  9. Mathematical epidemiology

    CERN Document Server

    Driessche, Pauline; Wu, Jianhong

    2008-01-01

    Based on lecture notes of two summer schools with a mixed audience from mathematical sciences, epidemiology and public health, this volume offers a comprehensive introduction to basic ideas and techniques in modeling infectious diseases, for the comparison of strategies to plan for an anticipated epidemic or pandemic, and to deal with a disease outbreak in real time. It covers detailed case studies for diseases including pandemic influenza, West Nile virus, and childhood diseases. Models for other diseases including Severe Acute Respiratory Syndrome, fox rabies, and sexually transmitted infections are included as applications. Its chapters are coherent and complementary independent units. In order to accustom students to look at the current literature and to experience different perspectives, no attempt has been made to achieve united writing style or unified notation. Notes on some mathematical background (calculus, matrix algebra, differential equations, and probability) have been prepared and may be downlo...

  10. EPRI epidemiology

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    A fight is brewing within the electric power community over the fate of a proposed $5 to $8 million epidemiological study of the effects of radiation on US nuclear plant workers. Several industry experts, claiming the project would merely lead to confusion by producing no clear results, are trying to prevent the Electric Power Research Institute (EPRI) from funding what would be the largest ever occupational study of this kind, covering perhaps as many as 500,000 workers. Ralph Lapp, a well-known radiation physicist, says that EPRI is facing unprecedented technical dissent from within. He claims there is already plenty of evidence that nuclear utilities are among the safest places to work, at least in terms of cancer risk, and that the proposed EPRI study would raise new concerns without yielding any answers

  11. Can iron plaque affect Sb(III) and Sb(V) uptake by plants under hydroponic conditions

    NARCIS (Netherlands)

    Ji, Ying; Lenz, Markus; Lenz, Markus; Schulin, Rainer; Tandy, Susan

    2018-01-01

    Antimony (Sb) contamination of soils is of concern due to h uman activities such as recycling of Sb containing Pb acid batteries, shooting and mining. However Sb uptake by plants is poorly documented, especially when plants are growing on waterlogged soils and iron plaques form on their roots. The

  12. Spina Bifida

    Science.gov (United States)

    ... with language and reading comprehension, and trouble learning math. Additional problems such as latex allergies, skin problems, ... and fetal ultrasound. The MSAFP screen measures the level of a protein called alpha-fetoprotein (AFP), which ...

  13. Spina Bifida

    Science.gov (United States)

    ... how your baby’s brain, spine, spinal cord and meninges develop. Meninges are the tissues that cover and protect the ... defect . In this condition, the fat, bone or meninges around the spinal cord don’t form correctly. ...

  14. Lower lattice thermal conductivity in SbAs than As or Sb monolayers: a first-principles study.

    Science.gov (United States)

    Guo, San-Dong; Liu, Jiang-Tao

    2017-12-06

    Phonon transport in group-VA element (As, Sb and Bi) monolayer semiconductors has been widely investigated in theory, and, of them, monolayer Sb (antimonene) has recently been synthesized. In this work, phonon transport in monolayer SbAs is investigated with a combination of first-principles calculations and the linearized phonon Boltzmann equation. It is found that the lattice thermal conductivity of monolayer SbAs is lower than those of both monolayer As and Sb, and the corresponding sheet thermal conductance is 28.8 W K -1 at room temperature. To understand the lower lattice thermal conductivity in monolayer SbAs than those in monolayer As and Sb, the group velocities and phonon lifetimes of monolayer As, SbAs and Sb are calculated. The calculated results show that the group velocities of monolayer SbAs are between those of monolayer As and Sb, but that the phonon lifetimes of SbAs are smaller than those of both monolayer As and Sb. Hence, the low lattice thermal conductivity in monolayer SbAs is attributed to very small phonon lifetimes. Unexpectedly, the ZA branch has very little contribution to the total thermal conductivity, only 2.4%, which is obviously different from those of monolayer As and Sb with very large contributions. This can be explained by very small phonon lifetimes for the ZA branch of monolayer SbAs. The lower lattice thermal conductivity of monolayer SbAs compared to that of monolayer As or Sb can be understood by the alloying of As (Sb) with Sb (As), which should introduce phonon point defect scattering. We also consider the isotope and size effects on the lattice thermal conductivity. It is found that isotope scattering produces a neglectful effect, and the lattice thermal conductivity with a characteristic length smaller than 30 nm can reach a decrease of about 47%. These results may offer perspectives on tuning the lattice thermal conductivity by the mixture of multiple elements for applications of thermal management and

  15. Sorghum phytochrome B inhibits flowering in long days by activating expression of SbPRR37 and SbGHD7, repressors of SbEHD1, SbCN8 and SbCN12.

    Directory of Open Access Journals (Sweden)

    Shanshan Yang

    Full Text Available Light signaling by phytochrome B in long days inhibits flowering in sorghum by increasing expression of the long day floral repressors PSEUDORESPONSE REGULATOR PROTEIN (SbPRR37, Ma1 and GRAIN NUMBER, PLANT HEIGHT AND HEADING DATE 7 (SbGHD7, Ma6. SbPRR37 and SbGHD7 RNA abundance peaks in the morning and in the evening of long days through coordinate regulation by light and output from the circadian clock. 58 M, a phytochrome B deficient (phyB-1, ma3R genotype, flowered ∼60 days earlier than 100 M (PHYB, Ma3 in long days and ∼11 days earlier in short days. Populations derived from 58 M (Ma1, ma3R, Ma5, ma6 and R.07007 (Ma1, Ma3, ma5, Ma6 varied in flowering time due to QTL aligned to PHYB/phyB-1 (Ma3, Ma5, and GHD7/ghd7-1 (Ma6. PHYC was proposed as a candidate gene for Ma5 based on alignment and allelic variation. PHYB and Ma5 (PHYC were epistatic to Ma1 and Ma6 and progeny recessive for either gene flowered early in long days. Light signaling mediated by PhyB was required for high expression of the floral repressors SbPRR37 and SbGHD7 during the evening of long days. In 100 M (PHYB the floral activators SbEHD1, SbCN8 and SbCN12 were repressed in long days and de-repressed in short days. In 58 M (phyB-1 these genes were highly expressed in long and short days. Furthermore, SbCN15, the ortholog of rice Hd3a (FT, is expressed at low levels in 100 M but at high levels in 58 M (phyB-1 regardless of day length, indicating that PhyB regulation of SbCN15 expression may modify flowering time in a photoperiod-insensitive manner.

  16. Liquidus Projection and Isothermal Section of the Sb-Se-Sn System

    Science.gov (United States)

    Chang, Jui-shen; Chen, Sinn-wen

    2017-12-01

    Sb-Se-Sn ternary alloys are promising chalcogenide materials. The liquidus projection and 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system are determined. Numerous Sb-Se-Sn alloys are prepared, and their primary solidification phases are examined. In addition to the three terminal phases, (Sb), (Se) and (Sn), there are Sb2Sn3, SbSn, SnSe, SnSe2, Sb2Se3, Sn2Sb9Se9, and SnSb2Se4 phases. In addition, there are two miscibility gaps along the Sb-Se and Se-Sn and sides. There are ten invariant reactions in the Sb-Se-Sn ternary system, and seven of them are experimentally determined in this study. The lowest reaction temperature of determined invariant reaction is L + SbSn = (Sn) + SnSe at 515.4 K ± 5 K (242.2 °C ± 5 °C). There are nine tie-triangles, which are Liquid + SbSn + SnSe, SbSn + SnSe + (Sb), SnSe + (Sb) + Sn2Sb9Se9, (Sb) + Sb2Se3 + Sn2Sb9Se9, SnSe + Sn2Sb9Se9 + SnSb2Se4, Sb2Se3 + Sn2Sb9Se9 + SnSb2Se4, SnSe + SnSe2 + SnSb2Se4, SnSe2 + SnSb2Se4 + Sb2Se3, and SnSe2 + Sb2Se3 + Liquid in the 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system.

  17. Thermoelectric properties of ZnSb films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Venkatasubramanian, R; Watko, E; Colpitts, T

    1997-07-01

    The thermoelectric properties of ZnSb films grown by metallorganic chemical vapor deposition (MOCVD) are reported. The growth conditions necessary to obtain stoichiometric ZnSb films and the effects of various growth parameters on the electrical conductivity and Seebeck coefficients of the films are described. The as-grown ZnSb films are p-type. It was observed that the thicker ZnSb films offer improved carrier mobilities and lower free-carrier concentration levels. The Seebeck coefficient of ZnSb films was found to rise rapidly at approximately 160 C. The thicker films, due to the lower doping levels, indicate higher Seebeck coefficients between 25 to 200 C. A short annealing of the ZnSb film at temperatures of {approximately}200 C results in reduced free-carrier level. Thermal conductivity measurements of ZnSb films using the 3-{omega} method are also presented.

  18. Percutaneous fetoscopic closure of large open spina bifida using a bilaminar skin substitute.

    Science.gov (United States)

    Lapa Pedreira, Denise A; Acacio, Gregório L; Gonçalves, Rodrigo T; Sá, Renato Augusto M; Brandt, Reynaldo A; Chmait, Ramen; Kontopoulos, Eftichia; Quintero, Ruben A

    2018-01-04

    We have previously described our percutaneous fetoscopic technique for the treatment of open spina bifida (OSB). However, approximately 20-30% of OSB defects are too large to allow primary skin closure. We hereby describe a modification of our standard technique using a bilaminar skin substitute to allow closure of such large spinal defects. The aim of this study was to report our clinical experience with the use of a bilaminar skin substitute and a percutaneous fetoscopic technique for the prenatal closure of large spina bifida defects. Surgeries were performed between 24.0 and 28.9 gestational weeks under general anesthesia, using an entirely percutaneous fetoscopic approach with partial CO2 insufflation of the uterine cavity, as previously described. If there was enough skin to be sutured in the midline, only a biocellulose patch was placed over the placode. In cases where skin approximation was not possible, a bilaminar skin substitute (two layers: one silicone and one dermal matrix) was placed over the biocellulose. The surgical site was assessed at birth, and long-term follow-up was performed. Forty-seven consecutive fetuses underwent percutaneous fetoscopic OSB repair. Premature preterm rupture of membranes (PPROM) occurred in 38 (84%), and the mean gestational age at delivery was 32,8 + 2.5 weeks. A bilaminar skin substitute was required in 13 (29%), of which 5 was associated with myeloschisis. In all cases the skin substitute was found at the surgical site, at birth. In 3 (15%) of these cases, postnatal additional repair was needed. In the other 10 cases, the silicone layer detached spontaneously from the dermal matrix (average 25 days after birth), and the lesion healed by secondary-intention. Operating time was significantly longer in cases requiring the bilaminar skin substitute (additional 42 minutes). The subgroup with bilaminar skin substitute had similar PPROM rate and delivery gestational age compared to the one patch group. Complete reversal of

  19. In As{sub 1–x}Sb{sub x} heteroepitaxial structures on compositionally graded GaInSb and AlGaInSb buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Guseynov, R. R.; Tanriverdiyev, V. A. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan); Kipshidze, G., E-mail: gela.kishidze@stonybrook.ede [Stony Brook, Stony Brook University (United States); Aliyeva, Ye. N.; Aliguliyeva, Kh. V.; Abdullayev, N. A., E-mail: abnadir@mail.ru; Mamedov, N. T. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)

    2017-04-15

    Unrelaxed InAs{sub 1–x}Sb{sub x} (x = 0.43 and 0.38) alloy layers are produced by molecular-beam epitaxy on compositionally graded GaInSb and AlGaInSb buffer layers. The high quality of the thin films produced is confirmed by the results of high-resolution X-ray diffraction analysis and micro-Raman studies. The twomode type of transformation of the phonon spectra of InAs{sub 1–x}Sb{sub x} alloys is established.

  20. Effect of InSb/In0.9Al0.1Sb superlattice buffer layer on the structural and electronic properties of InSb films

    Science.gov (United States)

    Zhao, Xiaomeng; Zhang, Yang; Guan, Min; Cui, Lijie; Wang, Baoqiang; Zhu, Zhanping; Zeng, Yiping

    2017-07-01

    The effect of InSb/In0.9Al0.1Sb buffer layers on InSb thin films grown on GaAs (0 0 1) substrate by molecular beam epitaxy (MBE) is investigated. The crystal quality and the surface morphology of InSb are characterized by XRD and AFM. The carrier transport property is researched through variable temperature hall test. The sharp interface between InSb/In0.9Al0.1Sb is demonstrated important for the high quality InSb thin film. We try different superlattice buffer layers by changing ratios, 2-0.5, thickness, 300-450 nm, and periods, 20-50. According to the function of the dislocation density to the absolute temperature below 150 K with different periods of SL buffers, we can find that the number of periods of superlattice is a major factor to decrease the density of threading dislocations. With the 50 periods SL buffer layer, the electron mobility of InSb at the room temperature and liquid nitrogen cooling temperature is ∼63,000 and ∼4600 cm2/V s, respectively. We deduce that the interface in the SL structure works as a filter layer to prevent the dislocation propagating to the upper InSb thin films.

  1. Coccidioidomycosis: epidemiology

    Directory of Open Access Journals (Sweden)

    Brown J

    2013-06-01

    Full Text Available Jennifer Brown,1 Kaitlin Benedict,2 Benjamin J Park,2 George R Thompson III1,31Department of Internal Medicine, Division of Infectious Diseases, University of California, Davis Medical Center, Sacramento, CA, USA; 2Mycotic Diseases Branch, Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA; 3Department of Medical Microbiology and Immunology, One Shields Avenue, Tupper Hall, Coccidioidomycosis Serology Laboratory, University of California, Davis, CA, USAAbstract: Coccidioidomycosis consists of a spectrum of disease, ranging from a mild, self-limited, febrile illness to severe, life-threatening infection. It is caused by the soil-dwelling fungi, Coccidioides immitis and C. posadasii, which are present in diverse endemic areas. Climate changes and environmental factors affect the Coccidioides lifecycle and influence infection rates. The incidence of coccidioidomycosis has risen substantially over the past two decades. The vast majority of Coccidioides infections occur in the endemic zones, such as California, Arizona, Mexico, and Central America. Infections occurring outside those zones appear to be increasingly common, and pose unique clinical and public health challenges. It has long been known that elderly persons, pregnant women, and members of certain ethnic groups are at risk for severe or disseminated coccidioidomycosis. In recent years, it has become evident that persons with immunodeficiency diseases, diabetics, transplant recipients, and prisoners are also particularly vulnerable.Keywords: coccidioidomycosis, Coccidioides, epidemiology, incidence, risk factors, geography

  2. 4. Managing Children with Spina Bifida in sub-Saharan Africa

    African Journals Online (AJOL)

    Esem

    taboos, religious beliefs, paucity of medical power. 1-5 ... interventions of rehabilitation for children with SB especially in Africa, some ... checked for and the central nervous system (CNS) ..... Thesis,. University of Zambia. 33. Sacko O, Boetto S, Lauwers-Cances V, Dupuy. M, Roux ... Nichols DS, Case-Smith J. Reliability and.

  3. Antimony Redox Biotransformation in the Subsurface: Effect of Indigenous Sb(V) Respiring Microbiota.

    Science.gov (United States)

    Wang, Liying; Ye, Li; Yu, Yaqin; Jing, Chuanyong

    2018-02-06

    Anaerobic microbiological antimonate [Sb(V)] respiration is a newly discovered process regulating the Sb redox transformation in soils. However, little is known about the role microbiological Sb(V) respiration plays in the fate of Sb in the subsurface, especially in the presence of sulfate and electron shuttles. Herein, we successfully enriched a Sb(V) reducing microbiota (SbRM) from the subsurface near an active Sb mine. SbRM was dominated by genus Alkaliphilus (18-36%), Clostridiaceae (17-18%), Tissierella (24-27%), and Lysinibacillus (16-37%). The incubation results showed that SbRM reduced 88% of dissolved Sb(V) to Sb(III), but the total Sb mobility remained the same as in the abiotic control, indicating that SbRM alone did not increase the total Sb release but regulated the Sb speciation in the subsurface. Micro X-ray fluorescence (μ-XRF) analysis suggested the association of Sb and Fe, and electron shuttles such as anthraquinone-2,6-disulfonic disodium salt (AQDS) markedly enhanced the Sb release due to its ability to facilitate Fe mineral dissolution. Sb L-edge and S K-edge X-ray absorption near edge structure (XANES) results demonstrated that indigenous SbRM immobilized Sb via Sb 2 S 3 formation, especially in a sulfur-rich environment. The insights gained from this study shed new light on Sb mobilization and its risk assessment in the subsurface environment.

  4. Evaporation of tetramers in Sb4n clusters and conditions for the formation of Sb2n+1 clusters

    International Nuclear Information System (INIS)

    Rayane, D.; Tribollet, B.; Broyer, M.; Melinon, P.; Cabaud, B.; Hoareau, A.

    1989-01-01

    Antimony clusters are produced by the inert gas condensation technique. They are found to be built from Sb 4 units. The fragmentation by evaporation of Sb 4 units is studied as a function of the excess energy in the cluster. By this way the binding energy of the Sb 4 units in the cluster is found to be about 1.5 eV, well below the binding energy of a Sb atom in the bulk and in Sb 4 (≅3 eV). The evolution of ionization potentials of Sb 4n clusters confirms that their structure is probably non metallic. Finally the possible metastable character of this Sb 4n structure is discussed. (orig.)

  5. [Eco-epidemiology: towards epidemiology of complexity].

    Science.gov (United States)

    Bizouarn, Philippe

    2016-05-01

    In order to solve public health problems posed by the epidemiology of risk factors centered on the individual and neglecting the causal processes linking the risk factors with the health outcomes, Mervyn Susser proposed a multilevel epidemiology called eco-epidemiology, addressing the interdependence of individuals and their connection with molecular, individual, societal, environmental levels of organization participating in the causal disease processes. The aim of this epidemiology is to integrate more than a level of organization in design, analysis and interpretation of health problems. After presenting the main criticisms of risk-factor epidemiology focused on the individual, we will try to show how eco-epidemiology and its development could help to understand the need for a broader and integrative epidemiology, in which studies designed to identify risk factors would be balanced by studies designed to answer other questions equally vital to public health. © 2016 médecine/sciences – Inserm.

  6. Hole-dominated transport in InSb nanowires grown on high-quality InSb films

    Energy Technology Data Exchange (ETDEWEB)

    Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U., E-mail: usha.philipose@unt.edu [University of North Texas, Department of Physics (United States)

    2016-12-15

    We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between Sb{sub 2}S{sub 3} and In and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40–60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 10{sup 17} cm{sup −3} and 1000 cm{sup 2} V{sup −1} s{sup −1}, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

  7. Synthesis and thermoelectric properties of Sb{sub 0.20}CoSb{sub 2.80} skutterudite

    Energy Technology Data Exchange (ETDEWEB)

    Figueirêdo, C.A., E-mail: camila_fig@hotmail.com [Universidade Federal do Rio Grande do Sul, PGCIMAT, Instituto de Física, 91501-970 Porto Alegre, RS (Brazil); Gallas, M.R. [Universidade Federal do Rio Grande do Sul, PGCIMAT, Instituto de Física, 91501-970 Porto Alegre, RS (Brazil); Institute for Multiscale Simulations, Friedrich-Alexander-Universität, Nägelsbachstrasse 49b, 91052 Erlangen (Germany); Zorzi, J.E. [Universidade de Caxias do Sul, Instituto de Materiais Cerâmicos, 95765-000 Bom Princípio, RS (Brazil); Perottoni, C.A. [Universidade Federal do Rio Grande do Sul, PGCIMAT, Instituto de Física, 91501-970 Porto Alegre, RS (Brazil); Universidade de Caxias do Sul, Instituto de Materiais Cerâmicos, 95765-000 Bom Princípio, RS (Brazil)

    2014-06-15

    Highlights: • A HP-HT Sb{sub 0.20}CoSb{sub 2.80} phase was prepared by processing cobalt antimonide at 7.7 GPa and 550 °C, for (at least) 5 min. • The mechanism of formation of this phase involves (i) decomposition of cobalt antimonide into CoSb{sub 2} and Sb, and (ii) insertion of Sb into the remaining cobalt antimonide. • The mechanism of formation is qualitatively different from that responsible for the formation of the high pressure (greater than 20 GPa) phase. - Abstract: Polycrystalline samples of cobalt antimonide (CoSb{sub 2.79}) were submitted to different conditions of pressure, temperature and processing time, in a high-pressure toroidal-type chamber, aiming to maximize the production of the high pressure phase previously observed in experiments with a diamond anvil cell. Rietveld refinements of X-ray powder diffraction data were performed to determine the phase composition and structural parameters. The maximum yield, 89(2) wt.% of Sb{sub x}CoSb{sub 3−x} phase, was obtained at 7.7 GPa, 550 °C and (at least) 5 min of processing time. The mechanism behind the formation of Sb{sub x}CoSb{sub 3−x} at high pressure and high temperature is actually not the same as that previously inferred from experiments at higher pressures (20 GPa) and room temperature with the diamond anvil cell. Indeed, evidences suggest that, at high pressure and high temperature, Sb{sub x}CoSb{sub 3−x} is formed by insertion of Sb resulting from decomposition of cobalt antimonide. Thermal conductivity, Seebeck coefficient and electrical conductivity were estimated for CoSb{sub 2.79} and Sb{sub 0.20}CoSb{sub 2.80}. The thermoelectric figure of merit at room temperature for Sb{sub 0.20}CoSb{sub 2.80} resulted 33% greater than that for CoSb{sub 2.79}.

  8. Clinical epidemiology.

    Science.gov (United States)

    Martin, S W; Bonnett, B

    1987-06-01

    Rational clinical practice requires deductive particularization of diagnostic findings, prognoses, and therapeutic responses from groups of animals (herds) to the individual animal (herd) under consideration This process utilizes concepts, skills, and methods of epidemiology, as they relate to the study of the distribution and determinants of health and disease in populations, and casts them in a clinical perspective.We briefly outline diagnostic strategies and introduce a measure of agreement, called kappa, between clinical diagnoses. This statistic is useful not only as a measure of diagnostic accuracy, but also as a means of quantifying and understanding disagreement between diagnosticians. It is disconcerting to many, clinicians included, that given a general deficit of data on sensitivity and specificity, the level of agreement between many clinical diagnoses is only moderate at best with kappa values of 0.3 to 0.6.Sensitivity, specificity, pretest odds, and posttest probability of disease are defined and related to the interpretation of clinical findings and ancillary diagnostic test results. An understanding of these features and how they relate to ruling-in or ruling-out a diagnosis, or minimizzing diagnostic errors will greatly enhance the diagnostic accuracy of the practitioner, and reduce the frequency of clinical disagreement. The approach of running multiple tests on every patient is not only wasteful and expensive, it is unlikely to improve the ability of the clinician to establish the correct diagnosis.We conclude with a discussion of how to decide on the best therapy, a discussion which centers on, and outlines the key features of, the well designed clinical trial. Like a diagnosis, the results from a clinical trial may not always be definitive, nonetheless it is the best available method of gleaning information about treatment efficacy.

  9. Anatomical and diffusion MRI of deep gray matter in pediatric spina bifida

    Directory of Open Access Journals (Sweden)

    Ashley L. Ware

    2014-01-01

    Full Text Available Individuals with spina bifida myelomeningocele (SBM exhibit brain abnormalities in cortical thickness, white matter integrity, and cerebellar structure. Little is known about deep gray matter macro- and microstructure in this population. The current study utilized volumetric and diffusion-weighted MRI techniques to examine gray matter volume and microstructure in several subcortical structures: basal ganglia nuclei, thalamus, hippocampus, and amygdala. Sixty-six children and adolescents (ages 8–18; M = 12.0, SD = 2.73 with SBM and typically developing (TD controls underwent T1- and diffusion-weighted neuroimaging. Microstructural results indicated that hippocampal volume was disproportionately reduced, whereas the putamen volume was enlarged in the group with SBM. Microstructural analyses indicated increased mean diffusivity (MD and fractional anisotropy (FA in the gray matter of most examined structures (i.e., thalamus, caudate, hippocampus, with the putamen exhibiting a unique pattern of decreased MD and increased FA. These results provide further support that SBM differentially disrupts brain regions whereby some structures are volumetrically normal whereas others are reduced or enlarged. In the hippocampus, volumetric reduction coupled with increased MD may imply reduced cellular density and aberrant organization. Alternatively, the enlarged volume and significantly reduced MD in the putamen suggest increased density.

  10. Attention in spina bifida myelomeningocele: Relations with brain volume and integrity

    Directory of Open Access Journals (Sweden)

    Paulina A. Kulesz

    2015-01-01

    Full Text Available This study investigated the relations of tectal volume and superior parietal cortex, as well as alterations in tectocortical white matter connectivity, with the orienting and executive control attention networks in individuals with spina bifida myelomeningocele (SBM. Probabilistic diffusion tractography and quantification of tectal and superior parietal cortical volume were performed on 74 individuals aged 8–29 with SBM and a history of hydrocephalus. Behavioral assessments measured posterior (covert orienting and anterior (conflict resolution, attentional control attention network functions. Reduced tectal volume was associated with slower covert orienting; reduced superior parietal cortical volume was associated with slower conflict resolution; and increased axial diffusivity and radial diffusivity along both frontal and parietal tectocortical pathways were associated with reduced attentional control. Results suggest that components of both the orienting and executive control attention networks are impaired in SBM. Neuroanatomical disruption to the orienting network appears more robust and a direct consequence of characteristic midbrain dysmorphology; whereas, executive control difficulties may emerge from parietal cortical anomalies and reduced frontal and parietal cortical–subcortical white matter pathways susceptible to the pathophysiological effects of congenital hydrocephalus.

  11. [The diagnostic process in spina bifida: parents perception and viewpoint of clinical specialists].

    Science.gov (United States)

    Herb, G; Streeck, S

    1995-01-01

    This is a study of the subjective experience of communicative understanding between parents of spina bifida children and medical personnel. Research methods include content analysis of data from semi-structured interviews, a questionnaire to explore the quality of life as well as conversation analytic reconstructions of the "real" communication processes during outpatient clinic which were tape-recorded. Results of the interviews with parents and personnel demonstrate the great relevance of the quality of the relationship in the providing of clinical care; equally important is that the relationship between parents and clinic staff is shaped in a reciprocal fashion. Discrepancies in the perceptions of parents and personnel indicate individual reality constructions. It is desirable that parents and personnel construct a shared reality during their interaction. With respect to this end, the emotional resources of personnel should be regarded as competences and drawn upon more systematically. The parents' role as "experts" should be validated and their active participation in the construction of the communicative situation - which is normally determined by the institution - should be encouraged.

  12. Neuroimaging parameters in early open spina bifida detection. Further benefit in first trimester screening?

    Science.gov (United States)

    Iliescu, D; Comănescu, A; Antsaklis, P; Tudorache, Stefania; Ghiluşi, Mirela; Comănescu, Violeta; Paulescu, Daniela; Ceauşu, Iuliana; Antsaklis, A; Novac, Liliana; Cernea, N

    2011-01-01

    Morphological investigation of the central nervous system (CNS) in fetuses with positive markers for open spina bifida (OSB) detection, visualized by ultrasound during the first trimester of pregnancy. Data from fetuses that underwent routine first trimester ultrasound scan in our center during September 2007-March 2011 and presented abnormal aspects of the fourth ventricle, also referred as intracranial translucency (IT), provided the morphological support to evaluate CNS features. A neuro-histological study of posterior cerebral fossa illustrated anatomical features of the structures involved in the sonographic first trimester detection of neural tube defects. Abnormal IT aspects were found in OSB cases examined in the first trimester, but also in other severe cerebral abnormalities. Brain stem antero-posterior diameter (BS) and brain stem to occipital bone (BSOB) ratio may be more specific for OSB detection. Correlations between histological aspects of posterior brain fossa and ultrasound standard assessment have been made; highlighting the anatomical features involved by the new techniques developed for OSB early detection. Preliminary results show that modern sonographic protocols are capable to detect abnormalities in the morphometry of the posterior brain. First trimester fourth ventricle abnormalities should be followed by careful CNS evaluation because are likely to appear in OSB affected fetuses, but also in other CNS severe anomalies; in such cases, normal BS and BSOB ratio may serve as indirect argument for spine integrity, if specificity is confirmed in large series of fetuses.

  13. Marital quality of parents of children with spina bifida: a case-comparison study.

    Science.gov (United States)

    Cappelli, M; McGarth, P J; Daniels, T; Manion, I; Schillinger, J

    1994-10-01

    The impact of childhood chronic illness on parents' marital quality has received limited attention. Most studies have relied solely on mothers' reports and have not examined differences between mothers and fathers. Using a case-control design, this study compared the marital quality within and between dyads of 46 couples with children matched on the age and children matched on the age and sex of the child. During a home visit, parents completed both self-report measures and a communication observational task. Mothers' and fathers' reports of marital quality did not differ between the two groups. Also, no significant differences were found on other marital and psychosocial measures. The most interesting correlations were observed for fathers of children with spinal bifida whose marital quality was associated with parenting stress (r = -.51), depression (r = -.34), and role strain (r = -.34). Overall, the results of this study contribute to the growing body of literature demonstrating that parents of children with a chronic condition are at no greater risk for psychosocial dysfunction, including marital distress, than parents of healthy children. However, to generalize the results, additional research on marital quality with other chronic conditions is required.

  14. Microbiological reduction of Sb(V) in anoxic freshwater sediments

    Science.gov (United States)

    Oremland, Ronald S.; Kulp, Thomas R.; Miller, Laurence G.; Braiotta, Franco; Webb, Samuel M.; Kocar, Benjamin D; Blum, Jodi S.

    2014-01-01

    Microbiological reduction of millimolar concentrations of Sb(V) to Sb(III) was observed in anoxic sediments from two freshwater settings: (1) a Sb- and As-contaminated mine site (Stibnite Mine) in central Idaho and 2) an uncontaminated suburban lake (Searsville Lake) in the San Francisco Bay Area. Rates of Sb(V) reduction in anoxic sediment microcosms and enrichment cultures were enhanced by amendment with lactate or acetate as electron donors but not by H2, and no reduction occurred in sterilized controls. Addition of 2-14C-acetate to Stibnite Mine microcosms resulted in the production of 14CO2 coupled to Sb(V) reduction, suggesting that this process proceeds by a dissimilatory respiratory pathway in those sediments. Antimony(V) reduction in Searsville Lake sediments was not coupled to acetate mineralization and may be associated with Sb-resistance. The microcosms and enrichment cultures also reduced sulfate, and the precipitation of insoluble Sb(III)-sulfide complexes was a major sink for reduced Sb. The reduction of Sb(V) by Stibnite Mine sediments was inhibited by As(V), suggesting that As(V) is a preferred electron acceptor for the indigenous community. These findings indicate a novel pathway for anaerobic microbiological respiration and suggest that communities capable of reducing high concentrations of Sb(V) commonly occur naturally in the environment.

  15. Epidemiologic study of neural tube defects in Los Angeles County. II. Etiologic factors in an area with low prevalence at birth

    Energy Technology Data Exchange (ETDEWEB)

    Sever, L.E.

    1982-01-01

    Epidemiologic characteristics of neural tube defect (NTD) births occurring in Los Angeles County, California, residents during the period 1966-1972 are presented. The prevalence at birth was 0.52/1000 births for anencephalus, 0.51/1000 for spina bifida, and 0.08/1000 for encephalocele, rates considered to be low for a predominantly white population. We hypothesized that environmental (nongenetic) factors are of less etiologic importance in a low-prevalence population than in areas or time periods with high prevalence. We tested that hypothesis by examining epidemiologic characteristics of NTDs in Los Angeles County and comparing them with high-prevalence populations. The data did not support a major etiologic role for environmental factors: (1) no significant differences between rates by month of birth or conception; (2) no significant association with maternal age or parity for anencephalus; for spina bifida a significant maternal age effect (P < 0.01) and for encephalocele a parity effect (P < 0.02); and (3) no significant relationship with father's occupational class for either anencephalus or encephalocele but a marginally significant (P < 0.05) inverse association for spina bifida when a statistic based on ordinal relationships was used. Findings supporting the importance of genetic factors in etiology included: (1) a high percentage of males; (2) a higher twin concordance rate than in high-prevalence populations; and (3) an anencephalus rate among blacks comparable with rates for blacks in other United States populations. Our findings in conjunction with those from other areas and times of low prevalence suggest environmental factors play a relatively insignificant role in the etiology of NTDs in such populations.

  16. DWPF Simulant CPC Studies For SB8

    Energy Technology Data Exchange (ETDEWEB)

    Newell, J. D.

    2013-09-25

    Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51 heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected

  17. First Case of Autonomic Dysreflexia Following Elective Lower Thoracic Spinal Cord Transection in a Spina Bifida Adult.

    Science.gov (United States)

    Garces, Juanita; Mathkour, Mansour; Scullen, Tyler; Kahn, Lora; Biro, Erin; Pham, Alex; Sulaiman, Olawale A R; Smith, Roger; Bui, Cuong J

    2017-12-01

    Spinal cord transection is a radical but effective treatment for highly selective cases of symptomatic spinal retethering in paraplegic spina bifida patients. Autonomic dysreflexia (AD) is a potentially life-threatening syndrome involving a dysregulated sympathetic discharge reflex commonly seen following cervical and high thoracic spinal cord injury, leading to a disconnect between autonomic pathways above and below the lesion that can lead to severe complications including uncontrolled hypertension, bradycardia, stroke, and potentially death. Herein we present a case in which a paraplegic spina bifida patient presenting with symptomatic spinal retethering experienced autonomic dysreflexia following an elective spinal cord transection. A 51-year-old male with a history of complex spina bifida presented with an active cerebrospinal fluid leak. Physical examination revealed a thin covering of abnormal epidermis over the large placode. Magnetic resonance imaging revealed a large myelomeningocele defect with posterior element defects spanning from L2 to the sacrum with evidence of tethering. The patient underwent an intradural transection of the spinal cord with a "blind-pouch" closure of the dura at the level of T12/L1. Postoperatively, the patient developed intermittent episodes of hypertension, bradycardia, headaches, altered mental status, severe perspiration, and red flushing of the upper torso, face, and arms. The diagnosis of AD was made clinically and managed with a positive response to a combination of beta- and alpha-blockade along with patient education on avoidance of common AD triggers. At 5-year follow-up the patient has continued to do well on medication. This case highlights a potential major side effect from elective transection of the spinal cord. If unrecognized and untreated, AD can cause significant distress and morbidity. We hope this first case report serves to supplement existing data and aid in future surgical and medical decision

  18. Sb{sup III} - Sb{sup V} Exchange Reaction in Hydrochloric: Acid Solutions; Echange Sb{sup III}-Sb{sup V} dans des Solutions d'Acide Chlorhydrique; Reaktsiya obmena Sb(III) - Sb(V) v rastvorakh khloristovodorodnoj kisloty; Intercambio Sb{sup III}-Sb{sup V} en Soluciones de HCl

    Energy Technology Data Exchange (ETDEWEB)

    Kambara, T.; Yamaguchi, K.; Yasuba, S. [Shizuoka University, Shizuoka City (Japan)

    1965-10-15

    The exchange reaction of Sb{sup III} - Sb{sup V} in solutions of low HCl concentrations was studied using {sup 124}Sb as a tracer. The effects of HCl concentrations and chemical forms of antimony on the exchange rate were investigated. The HCl concentrations of the antimony solutions ((Sb{sup III}) =(Sb{sup V}) = 6.8 x 10{sup -4}M) were changed from 0.8 to 4.0M and the half-time for the exchange was measured by plotting log (1 - F) versus time t to calculate the exchange rate assuming the second-ordet reaction. It was found that the exchange rate was sharply increased with the increase of HCl concentrations (at 25 Degree-Sign C, from 0.8 to 2.0M) and at 2.0M HCl concentration the rate reached the maximum, from which the rate was decreased with the increase of HCl concentrations (at 25 Degree-Sign C, from 2.0 to 4.0M). Two sorts of Sb{sup V} species were used for our investigations, i.e. one was used directly after the dilution of 10M HCl Sb{sup V} solution with water and the other was used after 24 hours standing at room temperature from the dilution. (The Sb{sup III} species were also kept standing after preparation from 10M HCl Sb{sup III} solution.) In both cases the maximum rates were found to exist at 2.0M HCl concentration. The rate R{sub 1} for the former (directly after dilution) was 4.5 x 10{sup -6} mole litre{sup -1} min{sup -1} and the rate R{sub 2} for the latter (24 hours standing) was 1.2 x 10{sup -}{sub 6} mole litre. Also the activation energy for these cases was found to be 12.2 kcal/mole and 19.1 kcal/mole. By spectrophotometric studies, the Sb{sup V} species of the former type were found to be mainly consisting of SbCl{sup -}{sub 6} and the species of the latter type to be of SbCl{sub 4}(OH){sup -}{sub 2}, etc. Besides these facts the form of Sb{sup III} species was found to have no influence on the exchange rate. A much sharper increase of the exchange rate was observed when the HCl concentration of the antimony solution was fixed at 0.8M and

  19. Optical and structural properties of MOVPE-grown GaInSb/GaSb quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Wagener, Viera, E-mail: viera.wagener@nmmu.ac.z [Physics Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Olivier, E.J.; Botha, J.R. [Physics Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2009-12-15

    This paper reports on the optical and structural properties of strained type-I Ga{sub 1-x}In{sub x}Sb quantum wells embedded in GaSb from a metal-organic vapour phase epitaxial growth perspective. Photoluminescence measurements and transmission electron microscopy were used to evaluate the effect of the growth temperature on the quality of Ga{sub 1-x}In{sub x}Sb strained layers with varied alloy compositions and thicknesses. Although the various factors contributing to the overall quality of the strained layers are difficult to separate, the quantum well characteristics are significantly altered by the growth temperature. Despite the high growth rates (approx2 nm/s), quantum wells grown at 607 deg. C display photoluminescence emissions with full-width at half-maximum of 3.5-5.0 meV for an indium solid content (x) up to 0.15.

  20. Electronic structure and high pressure phase transition in LaSb and CeSb

    International Nuclear Information System (INIS)

    Mathi Jaya, S.; Sanyal, S.P.

    1992-09-01

    The electronic structure and high pressure structural phase transition in cerium and lanthanum antimonides have been investigated using the tight binding LMTO method. The calculation of total energy reveals that the simple tetragonal structure is found to be stable at high pressures for both the compounds. In the case of LaSb, the calculated value of the equilibrium cell volume and the cell volume at which phase transition occurs are found to have a fairly good agreement with the experimental results. However, in the case of CeSb, the agreement is not as good as in LaSb. We also predicted the most favoured c/a value in the high pressure phase (simple tetragonal) for these compounds. Further we present the calculated results on the electronic structure of these systems at the equilibrium as well as at the reduced cell volumes. (author). 8 refs, 11 figs, 1 tab

  1. (In)GaSb/AlGaSb quantum wells grown on Si substrates

    International Nuclear Information System (INIS)

    Akahane, Kouichi; Yamamoto, Naokatsu; Gozu, Shin-ichiro; Ueta, Akio; Ohtani, Naoki

    2007-01-01

    We have successfully grown GaSb and InGaSb quantum wells (QW) on a Si(001) substrate, and evaluated their optical properties using photoluminescence (PL). The PL emissions from the QWs at room temperature were observed at around 1.55 μm, which is suitable for fiber optic communications systems. The measured ground state energy of each QW matched well with the theoretical value calculated by solving the Schroedinger equation for a finite potential QW. The temperature dependence of the PL intensity showed large activation energy (∼ 77.6 meV) from QW. The results indicated that the fabricated QW structure had a high crystalline quality, and the GaSb QW on Si for optical devices operating at temperatures higher than room temperature will be expected

  2. Optical and structural properties of MOVPE-grown GaInSb/GaSb quantum wells

    International Nuclear Information System (INIS)

    Wagener, Viera; Olivier, E.J.; Botha, J.R.

    2009-01-01

    This paper reports on the optical and structural properties of strained type-I Ga 1-x In x Sb quantum wells embedded in GaSb from a metal-organic vapour phase epitaxial growth perspective. Photoluminescence measurements and transmission electron microscopy were used to evaluate the effect of the growth temperature on the quality of Ga 1-x In x Sb strained layers with varied alloy compositions and thicknesses. Although the various factors contributing to the overall quality of the strained layers are difficult to separate, the quantum well characteristics are significantly altered by the growth temperature. Despite the high growth rates (∼2 nm/s), quantum wells grown at 607 deg. C display photoluminescence emissions with full-width at half-maximum of 3.5-5.0 meV for an indium solid content (x) up to 0.15.

  3. Electrodeposition and electrochemical characterisation of thick and thin coatings of Sb and Sb/Sb2O3 particles for Li-ion battery anodes

    International Nuclear Information System (INIS)

    Bryngelsson, Hanna; Eskhult, Jonas; Edstroem, Kristina; Nyholm, Leif

    2007-01-01

    The possibilities to electrodeposit thick coatings composed of nanoparticles of Sb and Sb 2 O 3 for use as high-capacity anode materials in Li-ion batteries have been investigated. It is demonstrated that the stability of the coatings depends on their Sb 2 O 3 concentrations as well as microstructure. The electrodeposition reactions in electrolytes with different pH and buffer capacities were studied using chronopotentiometry and electrochemical quartz crystal microbalance measurements. The obtained deposits, which were characterised with XRD and SEM, were also tested as anode materials in Li-ion batteries. The influence of the pH and buffer capacity of the deposition solution on the composition and particle size of the deposits were studied and it is concluded that depositions from a poorly buffered solution of antimony-tartrate give rise to good anode materials due to the inclusion of precipitated Sb 2 O 3 nanoparticles in the Sb coatings. Depositions under conditions yielding pure Sb coatings give rise to deposits composed of large crystalline particles with poor anode stabilities. The presence of a plateau at about 0.8 V versus Li + /Li due to SEI forming reactions and the origin of another plateau at about 0.4 V versus Li + /Li seen during the lithiation of thin Sb coatings are also discussed. It is demonstrated that the 0.4 V plateau is present for Sb coatings for which the (0 1 2) peak is the main peak in the XRD diffractogram

  4. Phase diagram of the Sb-Se-I system and thermodynamic properties of SbSeI

    International Nuclear Information System (INIS)

    Aliev, Z.S.; Musaeva, S.S.; Babanly, D.M.; Shevelkov, A.V.; Babanly, M.B.

    2010-01-01

    The Sb-Se-I system was investigated by using the DTA and XRD analyses and EMF measurements with an antimony electrode. The T-x diagram of the binary Sb-I system was accurately redefined. A number of polythermal sections and the projection of the liquidus surface were constructed. The fields of the primary crystallization, as well as the types and coordinates of non- and monovariant equilibria were determined. It is shown that the quasi-binary sections Sb 2 Se 3 -SbI 3 , Sb-SbSeI, SbI 3 -Se, and SbSeI-Se triangulate the Sb-Se-I system, leading to five independent subsystems. A broad area of immiscibility, that overlaps a certain part of the antimony primary crystallization field, was found. From the EMF measurements, the partial molar functions of antimony (ΔG-bar, ΔH-bar, ΔS-bar) as well as standard integral thermodynamic functions of SbSeI were calculated. The latter were found to have the following values: ΔG f,298 0 =-80.12±1.81kJ/mol; ΔH f,298 0 =-77.3±1.8kJ/mol; S 298 0 =155.2±9.5J/(molK).

  5. Phase diagram of the Sb-Se-I system and thermodynamic properties of SbSeI

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, Z S; Musaeva, S S; Babanly, D M [Baku State University, General and Inorganic Chemistry Department (Azerbaijan); Shevelkov, A.V., E-mail: shev@inorg.chem.msu.r [Moscow Lomonosov State University, Chemistry Department (Russian Federation); Babanly, M.B., E-mail: Babanly_mb@rambler.r [Baku State University, General and Inorganic Chemistry Department (Azerbaijan)

    2010-09-03

    The Sb-Se-I system was investigated by using the DTA and XRD analyses and EMF measurements with an antimony electrode. The T-x diagram of the binary Sb-I system was accurately redefined. A number of polythermal sections and the projection of the liquidus surface were constructed. The fields of the primary crystallization, as well as the types and coordinates of non- and monovariant equilibria were determined. It is shown that the quasi-binary sections Sb{sub 2}Se{sub 3}-SbI{sub 3}, Sb-SbSeI, SbI{sub 3}-Se, and SbSeI-Se triangulate the Sb-Se-I system, leading to five independent subsystems. A broad area of immiscibility, that overlaps a certain part of the antimony primary crystallization field, was found. From the EMF measurements, the partial molar functions of antimony ({Delta}G-bar, {Delta}H-bar, {Delta}S-bar) as well as standard integral thermodynamic functions of SbSeI were calculated. The latter were found to have the following values: {Delta}G{sub f,298}{sup 0}=-80.12{+-}1.81kJ/mol; {Delta}H{sub f,298}{sup 0}=-77.3{+-}1.8kJ/mol; S{sub 298}{sup 0}=155.2{+-}9.5J/(molK).

  6. Removal of Sb(III and Sb(V by Ferric Chloride Coagulation: Implications of Fe Solubility

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Inam

    2018-04-01

    Full Text Available Coagulation and precipitation appear to be the most efficient and economical methods for the removal of antimony from aqueous solution. In this study, antimony removal from synthetic water and Fe solubility with ferric chloride (FC coagulation has been investigated. The effects of pH, FC dosage, initial antimony loading and mixed Sb(III, Sb(V proportions on Fe solubility and antimony removal were studied. The results showed that the Sb(III removal efficiency increased with the increase of solution pH particularly due to an increase in Fe precipitation. The Sb(V removal was influenced by the solution pH due to a change in Fe solubility. However, the Fe solubility was only impaired by the Sb(III species at optimum pH 7. The removal efficiencies of both Sb species were enhanced with an increase in FC dose. The quantitative analysis of the isotherm study revealed the strong adsorption potential of Sb(III on Fe precipitates as compared to Sb(V. Furthermore, the removal behavior of antimony was inhibited in mixed proportion with high Sb(V fraction. In conclusion, this study contributes to better understanding the fate of Sb species, their mobilities, and comparative removal behavior, with implications for Fe solubility using ferric chloride in different aqueous environments.

  7. Hole-dominated transport in InSb nanowires grown on high-quality InSb films

    Science.gov (United States)

    Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U.

    2016-12-01

    We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between S b 2 S 3 and I n and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40-60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 1017 cm-3 and 1000 cm2 V-1 s-1, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

  8. Increased Sexual Health After Restored Genital Sensation in Male Patients with Spina Bifida or a Spinal Cord Injury: the TOMAX Procedure

    NARCIS (Netherlands)

    Overgoor, M. L. E.; de Jong, T. P. V. M.; Cohen-Kettenis, P. T.; Edens, M. A.; Kon, M.

    2013-01-01

    Purpose: In this study we prospectively investigated the contribution of restored penile sensation to sexual health in patients with low spinal lesions. Materials and Methods: In 30 patients (18 with spina bifida, 12 with spinal cord injury, age range 13 to 55 years) with no penile sensation but

  9. Inter-Tester Reliability and Precision of Manual Muscle Testing and Hand-Held Dynamometry in Lower Limb Muscles of Children with Spina Bifida

    Science.gov (United States)

    Mahony, Kate; Hunt, Adrienne; Daley, Deborah; Sims, Susan; Adams, Roger

    2009-01-01

    Reliability and measurement precision of manual muscle testing (MMT) and hand-held dynamometry (HHD) were compared for children with spina bifida. Strength measures were obtained of the hip flexors, hip abductors, and knee extensors of 20 children (10 males, 10 females; mean age 9 years 10 months; range: 5 to 15 years) by two experienced physical…

  10. The system Sb2Te3-InS

    International Nuclear Information System (INIS)

    Safarov, M.G.; Gamidov, R.S.; Poladov, P.M.

    1991-01-01

    The system Sb 2 Te 3 -InS was investigated by the methods of physicochemical analysis. Its state diagram was constructed. It represents the stable diagonal of the mutual ternary system InTe-Sb 2 Te 3 -Sb 2 S 3 -InS. It was established that limited regions of α- and β-solid solutions on the basis of Sb 2 Te 3 and InS, achieving 15.5 and 8 mol.% respectively, formed in the system. Lattice periods of α- and β-solid solutions, their lattice volumes, number of atoms in them and densities were calculated

  11. Optical response of confined excitons in GaInAsSb/GaSb Quantum Dots heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Cano, R [Departamento de Fisica, Universidad Autonoma de Occidente, A.A. 2790, Cali (Colombia); Tirado-Mejia, L; Fonthal, G; Ariza-Calderon, H [Laboratorio de Optoelectronica, Universidad del Quindio, A.A. 4603 Armenia (Colombia); Porras-Montenegro, N, E-mail: rsanchez40@gmail.co [Departamento de Fisica, Universidad del Valle, A.A. 25360, Cali (Colombia)

    2009-05-01

    The narrow-gap Ga{sub 1-x}In{sub x}As{sub y}Sb{sub 1-y} compounds are suitable materials for heterostructure devices operating in the infrared wavelength range. In these compounds grown by liquid phase epitaxy over GaSb single crystals, for x and y values in the range of 0.10 to 0.14 for both variables, the photoluminescence optical response at 12K is blue-shifted by 20 meV related to the photoreflectance response. We believe this behavior is due to possible higher electronic confinement in some places of the heterostructure, possibly formed in the interface during the growth process. In order to explain this behavior, in this work we study the exciton recombination energy in spherical Quantum Dots (QDs) on Ga{sub 1-x}In{sub x}As{sub y}Sb{sub 1-y}/GaSb, using the variational procedure within the effective-mass approximation and considering an electron in a Type I band alignment formed by two semiconductors with similar parabolic conduction bands. Our results are in good agreement with recent experimental results.

  12. Auditory agnosia due to long-term severe hydrocephalus caused by spina bifida - specific auditory pathway versus nonspecific auditory pathway.

    Science.gov (United States)

    Zhang, Qing; Kaga, Kimitaka; Hayashi, Akimasa

    2011-07-01

    A 27-year-old female showed auditory agnosia after long-term severe hydrocephalus due to congenital spina bifida. After years of hydrocephalus, she gradually suffered from hearing loss in her right ear at 19 years of age, followed by her left ear. During the time when she retained some ability to hear, she experienced severe difficulty in distinguishing verbal, environmental, and musical instrumental sounds. However, her auditory brainstem response and distortion product otoacoustic emissions were largely intact in the left ear. Her bilateral auditory cortices were preserved, as shown by neuroimaging, whereas her auditory radiations were severely damaged owing to progressive hydrocephalus. Although she had a complete bilateral hearing loss, she felt great pleasure when exposed to music. After years of self-training to read lips, she regained fluent ability to communicate. Clinical manifestations of this patient indicate that auditory agnosia can occur after long-term hydrocephalus due to spina bifida; the secondary auditory pathway may play a role in both auditory perception and hearing rehabilitation.

  13. Prenatal diagnosis and genetic counseling in a case of spina bifida in a family with Waardenburg syndrome type I.

    Science.gov (United States)

    Kujat, Annegret; Veith, Veit-Peter; Faber, Renaldo; Froster, Ursula G

    2007-01-01

    Waardenburg syndrome type I (WS I) is an autosomal dominant inherited disorder with an incidence of 1:45,000 in Europe. Mutations within the PAX3 gene are responsible for the clinical phenotype ranging from mild facial features to severe malformations detectable in prenatal diagnosis. Here, we report a four-generation family with several affected members showing various symptoms of WS I. We diagnosed the syndrome first in a pregnant young woman; she was referred because of a spina bifida in prenatal diagnosis. We performed clinical genetic investigations and molecular genetic analysis in all available family members. The phenotype displays a wide intra-familial clinical variability of pigmentary disturbances, facial anomalies and developmental defects. Molecular studies identified a novel splice site mutation within the PAX3 gene in intron 5 in all affected family members, but in none of the unaffected relatives. This case demonstrates the prenatal diagnosis of spina bifida in a fetus which leads to the initial diagnosis of WS I. Further studies could identify a private splice site mutation within the PAX3 gene responsible for the phenotype in this family.

  14. Crystallization and memory programming characteristics of Ge-doped SbTe materials of varying Sb : Te ratio

    International Nuclear Information System (INIS)

    Jeong, Jeung-hyun; Lee, Hyun Seok; Lee, Suyoun; Lee, Taek Sung; Kim, Won Mok; Wu Zhe; Cheong, Byung-ki; Kim, Seul Cham; Oh, Kyu Hwan

    2009-01-01

    A phase change memory (PCM) utilizes resistivity changes accompanying fast transitions from an amorphous to a crystalline phase (SET) and vice versa (RESET). An investigation was made on the SET characteristics of PCM cells with Ge-doped SbTe (Ge-ST) materials of two different Sb : Te ratios (4.53 and 2.08). For the material of higher Sb : Te (4.53), a SET operation was completed within several tens of nanoseconds via nucleation-free crystallization whereas the material of lower Sb : Te (2.08) rendered a slower SET operation requiring several hundred nanoseconds for a nucleation-mediated crystallization. From measurements of nucleation and growth kinetics via laser-induced crystallization, the observed SET characteristics of the former case were found to derive from a growth time about 10 3 times shorter than the nucleation time and those of the latter from a much shorter nucleation time as well as a longer growth time than in the former case. The measured nucleation kinetics of the lower Sb : Te (2.08) material is unexpected from the existing data, which has led us to advance an interesting finding that there occurs a trend-reversing change in the nucleation kinetics of the Ge-ST materials around the eutectic composition (Sb : Te ∼2.6); nucleation is accelerated with the increase in the Sb : Te ratio above Sb : Te of 2.6, but with a decrease in the Sb : Te ratio below it.

  15. Limiting scattering processes in high-mobility InSb quantum wells grown on GaSb buffer systems

    Science.gov (United States)

    Lehner, Ch. A.; Tschirky, T.; Ihn, T.; Dietsche, W.; Keller, J.; Fält, S.; Wegscheider, W.

    2018-05-01

    We present molecular beam epitaxial grown single- and double-side δ -doped InAlSb/InSb quantum wells with varying distances down to 50 nm to the surface on GaSb metamorphic buffers. We analyze the surface morphology as well as the impact of the crystalline quality on the electron transport. Comparing growth on GaSb and GaAs substrates indicates that the structural integrity of our InSb quantum wells is solely determined by the growth conditions at the GaSb/InAlSb transition and the InAlSb barrier growth. The two-dimensional electron gas samples show high mobilities of up to 349 000 cm2/Vs at cryogenic temperatures and 58 000 cm2/Vs at room temperature. With the calculated Dingle ratio and a transport lifetime model, ionized impurities predominantly remote from the quantum well are identified as the dominant source of scattering events. The analysis of the well-pronounced Shubnikov-de Haas oscillations reveals a high spin-orbit coupling with an effective g -factor of -38.4 in our samples. Along with the smooth surfaces and long mean free paths demonstrated, our InSb quantum wells are increasingly competitive for nanoscale implementations of Majorana mode devices.

  16. Sb-related defects in Sb-doped ZnO thin film grown by pulsed laser deposition

    Science.gov (United States)

    Luo, Caiqin; Ho, Lok-Ping; Azad, Fahad; Anwand, Wolfgang; Butterling, Maik; Wagner, Andreas; Kuznetsov, Andrej; Zhu, Hai; Su, Shichen; Ling, Francis Chi-Chung

    2018-04-01

    Sb-doped ZnO films were fabricated on c-plane sapphire using the pulsed laser deposition method and characterized by Hall effect measurement, X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and positron annihilation spectroscopy. Systematic studies on the growth conditions with different Sb composition, oxygen pressure, and post-growth annealing were conducted. If the Sb doping concentration is lower than the threshold ˜8 × 1020 cm-3, the as-grown films grown with an appropriate oxygen pressure could be n˜4 × 1020 cm-3. The shallow donor was attributed to the SbZn related defect. Annealing these samples led to the formation of the SbZn-2VZn shallow acceptor which subsequently compensated for the free carrier. For samples with Sb concentration exceeding the threshold, the yielded as-grown samples were highly resistive. X-ray diffraction results showed that the Sb dopant occupied the O site rather than the Zn site as the Sb doping exceeded the threshold, whereas the SbO related deep acceptor was responsible for the high resistivity of the samples.

  17. Improved structural and electrical properties in native Sb2Te3/GexSb2Te3+x van der Waals superlattices due to intermixing mitigation

    NARCIS (Netherlands)

    Cecchi, Stefano; Zallo, Eugenio; Momand, Jamo; Wang, Ruining; Kooi, Bart J.; Verheijen, Marcel A.; Calarco, Raffaella

    Superlattices made of Sb2Te3/GeTe phase change materials have demonstrated outstanding performance with respect to GeSbTe alloys in memory applications. Recently, epitaxial Sb2Te3/GeTe superlattices were found to feature GexSb2Te3+x blocks as a result of intermixing between constituting layers.

  18. Improved structural and electrical properties in native Sb2Te3/GexSb2Te3+x van der Waals superlattices due to intermixing mitigation

    NARCIS (Netherlands)

    Cecchi, S.; Zallo, E.; Momand, J.; Wang, R.; Kooi, B.J.; Verheijen, M.A.; Calarco, R.

    Superlattices made of Sb2Te3/GeTe phase change materials have demonstrated outstanding performance with respect to GeSbTe alloys in memory applications. Recently, epitaxial Sb2Te3/GeTe superlattices were found to feature GexSb2Te3+x blocks as a result of intermixing between constituting layers. Here

  19. Epidemiology of IBD

    Science.gov (United States)

    ... IBD? Projects and Partners Data and Statistics Resources Epidemiology of the IBD Recommend on Facebook Tweet Share ... 5:1424-9. 2 Loftus EV, Jr. Clinical epidemiology of inflammatory bowel disease: Incidence, prevalence, and environmental ...

  20. International Lymphoma Epidemiology Consortium

    Science.gov (United States)

    The InterLymph Consortium, or formally the International Consortium of Investigators Working on Non-Hodgkin's Lymphoma Epidemiologic Studies, is an open scientific forum for epidemiologic research in non-Hodgkin's lymphoma.

  1. Evaluation of epidemiological studies

    International Nuclear Information System (INIS)

    Breckow, J.

    1995-01-01

    The publication is intended for readers with a professional background in radiation protection who are not experts in the field of epidemiology. The potentials and the limits of epidemiology are shown and concepts and terminology of radioepidemilogic studies as well as epidemiology in general are explained, in order to provide the necessary basis for understanding or performing evaluations of epidemiologic studies. (orig./VHE) [de

  2. Preparation and crystal structure of Ca4Sb2O

    International Nuclear Information System (INIS)

    Eisenmann, B.; Limartha, H.; Schaefer, H.

    1980-01-01

    The formerly described compound Ca 2 Sb is to be corrected to Ca 4 Sb 2 O as shown by X-ray diffractometer data of single crystals and neutron diffraction diagrams of powders. The compound crystallizes in the K 2 NiF 4 structure type. (orig.)

  3. Neutron scattering study of Ce3Au3Sb4

    International Nuclear Information System (INIS)

    Kasaya, Mitsuo; Katoh, Kenichi; Kohgi, Masahumi; Osakabe, Toyotaka

    1993-01-01

    Rare-earth compounds with an Y 3 Au 3 Sb 4 -type crystal structure are semiconductors or semi-metals. Among them, Ce 3 Au 3 Sb 4 is a semiconductor with an activation energy of about 640 K and shows no magnetic order down to 1.5 K. The magnetic part of the specific heat for Ce 3 Au 3 Sb 4 obtained by subtracting the value for La 3 Au 3 Sb 4 from the total specific heat of Ce 3 Au 3 Sb 4 shows a broad peak at around 10 K, the origin of which is well explained by the crystalline-field splitting determined by neutron scattering. (author)

  4. Are Sb4n (n>1) clusters weakly interacting tetrahedra?

    International Nuclear Information System (INIS)

    Kumar, V.

    1993-03-01

    The electronic and atomic structure of Sb 4 and Sb 8 clusters is studied using the ab-initio molecular dynamics method in the local density approximation. While for Sb 4 we obtain a regular tetrahedron to be about 2.0 eV lower in energy than a bent rhombus, for Sb 8 two structures, (1) two weakly interaction tetrahedra and (2) a bent rhombus interacting with a stretched tetrahedron, obtained from the simulated annealing lie only within about 0.1 eV indicating the importance of the bent rhombus structure for larger clusters. As compared to two isolated tetrahedra, the binding energy of Sb 8 is about 0.5 eV. Our results are thus in excellent agreement with the experimental data which show predominantly the abundance of tetramers above room temperature. (author). 18 refs, 5 figs, 1 tab

  5. Thermoelectric properties and microstructure of Mg3Sb2

    International Nuclear Information System (INIS)

    Condron, Cathie L.; Kauzlarich, Susan M.; Gascoin, Franck; Snyder, G. Jeffrey

    2006-01-01

    Mg 3 Sb 2 has been prepared by direct reaction of the elements. Powder X-ray diffraction, thermal gravimetric, differential scanning calorimetery, and microprobe data were obtained on hot pressed samples. Single phase samples of Mg 3 Sb 2 were prepared and found to contain oxygen at the grain boundaries and to lose Mg and oxidize at temperatures above 900 K. Thermoelectric properties were characterized by Seebeck, electrical resistivity, and thermal conductivity measurements from 300 to 1023 K, and the maximum zT was found to be 0.21 at ∼875 K. - Graphical abstract: Dimensionless figure of merit for Mg 3 Sb 2 hot pressed and sintered at 873 K. The inset illustrates the crystal structure of Mg 3 Sb 2 along the [100] direction (white=Mg, black=Sb)

  6. A Summary of Rheology Data For SB3 and SB2/3 Blend Simulant Savannah River Site Wastes

    International Nuclear Information System (INIS)

    KOOPMAN, DAVIDC.

    2004-01-01

    The purpose of this study was to document the rheological measurements made for Sludge Batch 3 (SB3) and the blend of SB3 with Sludge Batch 2 (SB2). These measurements were primarily made on Slurry Mix Evaporator (SME) products, i.e. melter feeds. Some measurements were made on SB2/3 blend Sludge Receipt and Adjustment Tank (SRAT) products. Measurements on radioactive SB3 and SB2/3 samples have been limited to sludge characterization. SB2/3 measurements studied the impact of changing the SRAT acid addition strategy on the SRAT and SME product rheology. SB2/3 measurements also studied the impact of changing the waste loading target (sludge oxides content in glass) of the SME product. SB3 measurements studied the impact of changes in the wash end point and acid addition strategy on the SME product (melter feed) rheology. A summary of the significant findings is given below: SB3 radioactive sludge and blended SB2/3 radioactive sludge were less viscous than SB2 radioactive sludge. SB2/3 b lend sludge is more viscous than SB3 sludge. SB3 simulant SME product rheology was strongly impacted by changing the noble metal concentrations to more closely match those of the qualification sample. This reduction in noble metals produced a lower pH product that was also considerably less viscous. Increased acid addition in the SB2/3 SRAT generally led to less viscous simulant SRAT products. This trend did not persist in the SME products. SME products became more viscous when increased acid was used in the SRAT cycle from 135 per cent up to 170 per cent of stoichiometry, then became less viscous as total acid was increased further to 185 per cent. A significant increase in hydrogen generation occurred between 170 per cent and 185 per cent. The impact of acid addition on SB3 SME products was also variable. The impact of waste loading changes from 31 to 35 to 40 per cent on SB2/3 simulant SME products led to more viscous melter feeds as waste loading increased at constant wt. per cent

  7. Adducts of UF5 with SbF5 and structure of UF5 . 2SbF5

    International Nuclear Information System (INIS)

    Sawodny, W.; Rediess, K.

    1980-01-01

    Both α-UF 5 and β-UF 5 form only a 1:2 compound UF 5 . 2SbF 5 reacting directly with SbF 5 , from which UF 5 . SbF 5 can be obtained by thermal decomposition. UF 5 . 2SbF 5 crystallizes in the monoclinic space group P2 1 /c with the following lattice constants a = 8.110(4), b = 14.129(6), c = 10.032(6) A and β = 96.97(5) 0 ; Z = 4. An X-ray study shows centrosymmetric four-membered rings of alternating UF 8 and SbF 6 polyhedra connected by other SbF 6 entities. This structure is similar to that of UOF 5 . 2SbF 5 , but the distorted pentagonal-bipyramidal coordination of the U atom found there is increased to a dodecahedral coordination by an additional U-F-Sb bridge, though with a somewaht larger UF distance. (author)

  8. Role of interlayer coupling for the power factor of CuSbS2 and CuSbSe2

    KAUST Repository

    Alsaleh, Najebah Mohammed Abdullah; Singh, Nirpendra; Schwingenschlö gl, Udo

    2017-01-01

    The electronic and transport properties of bulk and monolayer CuSbS2 and CuSbSe2 are determined by using density functional theory and semiclassical Boltzmann transport theory, in order to investigate the role of interlayer coupling

  9. Photoemission study of the skutterudite compounds CoSb sub 3 and RhSb sub 3

    CERN Document Server

    Ishii, H; Fujimori, A; Nagamoto, Y; Koyanagi, T; Sofo, J O

    2002-01-01

    We have studied the electronic structure of the skutterudite compounds CoSb sub 3 and Co(Sb sub 0 sub . sub 9 sub 6 Te sub 0 sub . sub 0 sub 4) sub 3 by photoemission spectroscopy. Valence-band spectra revealed that a significant amount Sb 5p states are present near the Fermi level and are hybridized with Co 3d states just below it. The spectra are well reproduced by the band-structure calculation, suggesting that the effect of electron correlations is not important. When Te is substituted for Sb and n-type carriers are doped into CoSb sub 3 , the spectra are shifted to higher binding energies as described by the rigid-band model. From this shift and the free-electron model for the conduction and valence bands, we have estimated the band gap of CoSb sub 3 to be 0.03-0.04 eV, consistent with transport measurements. Photoemission spectra of RhSb sub 3 have also been measured and revealed expected similarities to and differences from those of CoSb sub 3. Unusual temperature dependence has been observed for the s...

  10. New Insights into the Origins of Sb-Induced Effects on Self-Catalyzed GaAsSb Nanowire Arrays

    DEFF Research Database (Denmark)

    Ren, Dingding; Dheeraj, Dasa L.; Jin, Chengjun

    2016-01-01

    and thermodynamically by the introduction of Sb. An anomalous decrease of the axial growth rate with increased Sb2 flux is found to be due to both the indirect kinetic influence via the Ga adatom diffusion induced catalyst geometry evolution and the direct composition modulation. From the fundamental growth analyses...

  11. Effect of antimony nano-scale surface-structures on a GaSb/AlAsSb distributed Bragg reflector

    International Nuclear Information System (INIS)

    Husaini, S.; Shima, D.; Ahirwar, P.; Rotter, T. J.; Hains, C. P.; Dang, T.; Bedford, R. G.; Balakrishnan, G.

    2013-01-01

    Effects of antimony crystallization on the surface of GaSb during low temperature molecular beam epitaxy growth are investigated. The geometry of these structures is studied via transmission electron and atomic force microscopies, which show the surface metal forms triangular-shaped, elongated nano-wires with a structured orientation composed entirely of crystalline antimony. By depositing antimony on a GaSb/AlAsSb distributed Bragg reflector, the field is localized within the antimony layer. Polarization dependent transmission measurements are carried out on these nano-structures deposited on a GaSb/AlAsSb distributed Bragg reflector. It is shown that the antimony-based structures at the surface favor transmission of light polarized perpendicular to the wires.

  12. Near-surface depletion of antimony during the growth of GaAsSb and GaAs/GaAsSb nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Kauko, H.; Helvoort, A. T. J. van, E-mail: a.helvoort@ntnu.no [Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Fimland, B. O.; Munshi, A. M. [Department of Electronics and Telecommunications, NTNU, Trondheim (Norway); Grieb, T.; Müller, K.; Rosenauer, A. [Institut für Festkörperphysik, Universität Bremen, Bremen (Germany)

    2014-10-14

    The near-surface reduction of the Sb mole fraction during the growth of GaAsSb nanowires (NWs) and GaAs NWs with GaAsSb inserts has been studied using quantitative high-angle annular dark field scanning transmission electron microscopy (STEM). A model for diffusion of Sb in the hexagonal NWs was developed and employed in combination with the quantitative STEM analysis. GaAsSb NWs grown by Ga-assisted molecular beam epitaxy (MBE) and GaAs/GaAsSb NWs grown by Ga- and Au-assisted MBE were investigated. At the high temperatures employed in the NW growth, As-Sb exchange at and outward diffusion of Sb towards the surface take place, resulting in reduction of the Sb concentration at and near the surface in the GaAsSb NWs and the GaAsSb inserts. In GaAsSb NWs, an increasing near-surface depletion of Sb was observed towards the bottom of the NW due to longer exposure to the As beam flux. In GaAsSb inserts, an increasing change in the Sb concentration profile was observed with increasing post-insert axial GaAs growth time, resulting from a combined effect of radial GaAs overgrowth and diffusion of Sb. The effect of growth temperature on the diffusion of Sb in the GaAsSb inserts was identified. The consequences of these findings for growth optimization and the optoelectronic properties of GaAsSb are discussed.

  13. Systematic review and practice policy statements on urinary tract infection prevention in adults with spina bifida

    Science.gov (United States)

    Tradewell, Michael; Pariser, Joseph J.; Nimeh, Tony

    2018-01-01

    Urinary tract infection (UTI) is a source of morbidity and healthcare costs in adults with spina bifida (ASB). UTI prevention strategies are often recommended, but the evidence of various approaches remains unclear. We performed a systematic review to inform a best practice policy statement for UTI prevention in ASB. On behalf of the Neurogenic Bladder Research Group (NBRG.org), we developed an a priori protocol and searched the published English literature for 30 outcomes questions addressing UTI prevention in ASB. The questions spanned the categories of antibiotics, oral supplements, bladder management factors and social support. Where there was little literature in ASB, we included literature from similar populations with neurogenic bladder (NB). Data was abstracted and then reviewed with recommendations made by consensus of all authors. Level of Evidence (LoE) and Grade of Recommendation (GoR) were according to the Oxford grading system. Of 6,433 articles identified by our search, we included 99 publications. There was sufficient evidence to support use of the following: saline bladder irrigation (LoE 1, GoR B), gentamicin bladder instillation (LoE 3, GoR C), single-use intermittent catheterization (IC) (LoE 2, GoR B), hydrophilic catheters for IC (LoE 2, GoR C), intradetrusor onabotulinumtoxinA injection (LoE 3, GoR C), hyaluronic acid (HA) instillation (LoE 1, GoR B), and care coordination (LoE 3, GoR C). There was sufficient evidence to recommend against use of the following: sterile IC (LoE 1, GoR B), oral antibiotic prophylaxis (LoE 2, GoR B), treatment of asymptomatic bacteriuria (LoE 2, GoR B), cranberry (LoE 2, GoR B), methenamine salts (LoE 1, GoR B), and ascorbic acid (LoE1, GoR B). There was insufficient evidence to make a recommendation for other outcomes. Overall, there are few studies in UTI prevention in the specific population of ASB. Research in populations similar to ASB helps to guide recommendations for UTI prevention in the challenging

  14. Study for material analogs of FeSb2: Material design for thermoelectric materials

    Science.gov (United States)

    Kang, Chang-Jong; Kotliar, Gabriel

    2018-03-01

    Using the ab initio evolutionary algorithm (implemented in uspex) and electronic structure calculations we investigate the properties of a new thermoelectric material FeSbAs, which is a material analog of the enigmatic thermoelectric FeSb2. We utilize the density functional theory and the Gutzwiller method to check the energetics. We find that FeSbAs can be made thermodynamically stable above ˜30 GPa. We investigate the electronic structure and thermoelectric properties of FeSbAs based on the density functional theory and compare with those of FeSb2. Above 50 K, FeSbAs has higher Seebeck coefficients than FeSb2. Upon doping, the figure of merit becomes larger for FeSbAs than for FeSb2. Another material analog FeSbP, was also investigated, and found thermodynamically unstable even at very high pressure. Regarding FeSb2 as a member of a family of compounds (FeSb2, FeSbAs, and FeSbP) we elucidate what are the chemical handles that control the gaps in this series. We also investigate solubility (As or P for Sb in FeSb2) we found As to be more soluble. Finally, we study a two-band model for thermoelectric properties and find that the temperature dependent chemical potential and the presence of the ionized impurities are important to explain the extremum in the Seebeck coefficient exhibited in experiments for FeSb2.

  15. Unusual crystallization behavior in Ga-Sb phase change alloys

    Directory of Open Access Journals (Sweden)

    Magali Putero

    2013-12-01

    Full Text Available Combined in situ X-ray scattering techniques using synchrotron radiation were applied to investigate the crystallization behavior of Sb-rich Ga-Sb alloys. Measurements of the sheet resistance during heating indicated a reduced crystallization temperature with increased Sb content, which was confirmed by in situ X-ray diffraction. The electrical contrast increased with increasing Sb content and the resistivities in both the amorphous and crystalline phases decreased. It was found that by tuning the composition between Ga:Sb = 9:91 (in at.% and Ga:Sb = 45:55, the change in mass density upon crystallization changes from an increase in mass density which is typical for most phase change materials to a decrease in mass density. At the composition of Ga:Sb = 30:70, no mass density change is observed which should be very beneficial for phase change random access memory (PCRAM applications where a change in mass density during cycling is assumed to cause void formation and PCRAM device failure.

  16. Positron annihilation studies of high dose Sb implanted silicon

    International Nuclear Information System (INIS)

    Schut, H.; Eijt, S.W.H.; Beling, C.D.; Ho, K.; Takamura, Y.

    2005-01-01

    The formation and evolution of vacancies and precipitates created by implantation of 60 keV, 2 x 10 16 cm -2 Sb + in pre-amorphized (0 0 1) Cz-Si is studied using the Doppler broadening (DB) and two-dimensional angular correlation of annihilation radiation (2D-ACAR) positron beam techniques. After implantation, samples were laser annealed (LTA) and subsequently thermal annealed at temperatures ranging from 400 to 1000 deg. C. Implantation-induced vacancy-type defects were detected up to a depth of 280 nm. After LTA, positron annihilation related to both Sb and remaining defects is observed in the first 100 nm below the surface. The deeper region only shows positron trapping at vacancy-type defects with strong reduced concentration. Complete removal is obtained after 600 deg. C anneal. At this temperature, the positron data for the upper region reveals trapping at Sb and Si sites only. With increasing annealing time (at 600 deg. C) or increasing temperature (up to 1000 deg. C) positron annihilation at Sb-sites associated with neighboring vacancies becomes apparent. Results are correlated with the observed Sb electrical deactivation above 600 deg. C, the shift from small Sb aggregates to precipitates and out-diffusion of Sb from the implantation region at higher temperatures

  17. Attention lapses in children with spina bifida and hydrocephalus and children with attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    De la Torre, Gabriel G; Martin, Alba; Cervantes, Elizabeth; Guil, Rocio; Mestre, Jose M

    2017-08-01

    Attentional lapses are usually defined as temporary and often brief shifts of attention away from some primary task to unrelated internal information processing. This study addressed the incidence of attention lapses and differences in attentional functioning in 30 children with attention-deficit/hyperactivity disorder (ADHD), 26 healthy children, and 29 children with spina bifida myelomeningocele and hydrocephalus (SBH). Assessments were conducted using computerized tonic and phasic attention tests, the Symbol Digit Modalities Test (SDMT), and the Trail Making Test Form B (TMT-B). The group with SBH differed from normal controls on cognitive measures of attention and executive functions. The ADHD group obtained lower scores than the SBH group and healthy children. ANOVA results showed that there was an effect of shunt revisions and shunt-related infections on neuropsychological performance. Lapses of attention together with reaction time may thus represent important factors for the understanding of cognitive deficits in SBH.

  18. Bluish Discolouration of Urine Drainage Tube and Bag in a Female Patient with Spina Bifida, Paraplegia, and Suprapubic Cystostomy

    Directory of Open Access Journals (Sweden)

    Subramanian Vaidyanathan

    2007-01-01

    Full Text Available We present a female patient with spina bifida, paraplegia, suprapubic cystostomy, and chronic constipation, who became anxious when she noticed a bluish discolouration of her urine drainage system. Urine microbiology revealed growth of Providencia stuartii and Staphylococcus aureus. There were no systemic features of infection and, therefore, antibiotics were not prescribed for asymptomatic bacteriuria. This patient was advised to change the urine bag every day, and was prescribed senna to facilitate bowel evacuation. She was reassured that bluish discolouration of the urine drainage tube and bag was a transient, benign phenomenon and not indicative of any underlying pathology. Over the next 7 days, the bluish discolouration gradually faded away. Clinical characteristics of patients who are likely to develop this phenomenon and the underlying biochemical mechanism for bluish discolouration of the urine drainage system are discussed in brief.

  19. Point defect balance in epitaxial GaSb

    International Nuclear Information System (INIS)

    Segercrantz, N.; Slotte, J.; Makkonen, I.; Kujala, J.; Tuomisto, F.; Song, Y.; Wang, S.

    2014-01-01

    Positron annihilation spectroscopy in both conventional and coincidence Doppler broadening mode is used for studying the effect of growth conditions on the point defect balance in GaSb:Bi epitaxial layers grown by molecular beam epitaxy. Positron annihilation characteristics in GaSb are also calculated using density functional theory and compared to experimental results. We conclude that while the main positron trapping defect in bulk samples is the Ga antisite, the Ga vacancy is the most prominent trap in the samples grown by molecular beam epitaxy. The results suggest that the p–type conductivity is caused by different defects in GaSb grown with different methods.

  20. Quaternary InGaAsSb Thermophotovoltaic Diode Technology

    International Nuclear Information System (INIS)

    M Dashiell; J Beausang; H Ehsani; G Nichols; D DePoy; L Danielson; P Talamo; K Rahner; E Brown; S Burger; P Fourspring; W Topper; P Baldasaro; C Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; Jizhong Li; R Martinelli; D Donetski; S Anikeev; G Belenky; S Luryl

    2005-01-01

    Thermophotovoltaic (TPV) diodes fabricated from InGaAsSb alloys lattice-matched to GaSb substrates are grown by Metal Organic Vapor Phase Epitaxy (MOVPE). 0.53eV InGaAsSb TPV diodes utilizing front-surface spectral control filters have been tested in a vacuum cavity and a TPV thermal-to-electric conversion efficiency (η TPV ) and a power density (PD) of η TPV = 19% and PD=0.58 W/cm 2 were measured for T radiator = 950 C and T diode = 27 C. Recombination coefficients deduced from minority carrier measurements and the theory reviewed in this article predict a practical limit to the maximum achievable conversion efficiency and power density for 0.53eV InGaAsSb TPV. The limits for the above operating temperatures are projected to be η TPV = 26% and PD = 0.75 W/cm 2 . These limits are extended to η TPV = 30% and PD = 0.85W/cm 2 if the diode active region is bounded by a reflective back surface to enable photon recycling and a two-pass optical path length. The internal quantum efficiency of the InGaAsSb TPV diode is close to the theoretically predicted limits, with the exception of short wavelength absorption in GaSb contact layers. Experiments show that the open circuit voltage of the 0.53eV InGaAsSb TPV diodes is not strongly dependent on the device architectures studied in this work where both N/P and P/N double heterostructure diodes have been grown with various acceptor and donor doping levels, having GaSb and AlGaAsSb confinement, and also partial back surface reflectors. Lattice matched InGaAsSb TPV diodes were fabricated with bandgaps ranging from 0.6 to 0.5eV without significant degradation of the open circuit voltage factor, quantum efficiency, or fill factor as the composition approached the miscibility gap. The key diode performance parameter which is limiting efficiency and power density below the theoretical limits in InGaAsSb TPV devices is the open circuit voltage. The open circuit voltages of state-of-the-art 0.53eV InGaAsSb TPV diode are ∼10

  1. First principles simulation of amorphous InSb

    Science.gov (United States)

    Los, Jan H.; Kühne, Thomas D.; Gabardi, Silvia; Bernasconi, Marco

    2013-05-01

    Ab initio molecular dynamics simulations based on density functional theory have been performed to generate a model of amorphous InSb by quenching from the melt. The resulting network is mostly tetrahedral with a minor fraction (10%) of atoms in a fivefold coordination. The structural properties are in good agreement with available x-ray diffraction and extended x-ray-absorption fine structure data and confirm the proposed presence of a sizable fraction of homopolar In-In and Sb-Sb bonds whose concentration in our model amounts to about 20% of the total number of bonds.

  2. Serial casting versus stretching technique to treat knee flexion contracture in children with spina bifida: a comparative study.

    Science.gov (United States)

    Al-Oraibi, S; Tariah, Hashem Abu; Alanazi, Abdullah

    2013-01-01

    Severe knee contractures that develop soon after muscle imbalance may not improve with stretching exercises and splinting. An alternative treatment is serial casting, which has been used to promote increased range of motion. The purpose of this study was to compare the effectiveness of using serial casting and passive stretching approaches to treat knee flexion contracture in children with spina bifida. In a pre/post randomized controlled study, ten participants were included in the serial casting group, while eight participants were included in the passive stretching intervention group. The degree of knee extension was measured at baseline, immediately after intervention, and at a one-year follow-up using a standard goniometer. Both groups showed significant improvements in the degree of flexion contracture at the post-treatment evaluation and the follow-up evaluation. The serial casting group showed significant improvements in knee flexion contracture at the post-treatment evaluation, t (9)=13.4, p casting group compared with passive stretching group in relation to the degree of flexion contracture were found at the immediate post-treatment evaluation, F(1, 15)=246, p=0.0001, and the one-year follow-up evaluation, F (1, 15)=51.5, p=0.0001. The outcomes of this study provide the first evidence that serial casting may be a useful intervention in treating knee flexion contracture in children with spina bifida. However, further investigations into serial casting, as well as investigations into the use of serial casting with other interventions, are warranted.

  3. Evaluation of sexual function in young men with spina bifida and myelomeningocele using the International Index of Erectile Function.

    Science.gov (United States)

    Gamé, Xavier; Moscovici, Jacques; Gamé, Laurence; Sarramon, Jean-Pierre; Rischmann, Pascal; Malavaud, Bernard

    2006-03-01

    To assess sexual function in young men with spina bifida and myelomeningocele. Between November 2003 and February 2004, a cross-sectional study was performed in 55 men older than 18 years of age who had been regularly followed up for myelomeningocele since childhood, between 1961 and 1985, in the Pediatric Internal Surgery Department. The International Index of Erectile Function (IIEF) questionnaire was mailed to each man. The response rate was 72.7%. Of the 40 men who replied, 16 (40%) had had sexual intercourse at least once during the previous month. These were the older men (age 31.9 +/- 5.7 years versus 27.7 +/- 5.5 years, P = 0.027). The IIEF scores for the whole group were erectile function 11.61 +/- 9.44, orgasmic function 3.53 +/- 3.86, sexual desire 6.94 +/- 2.4, intercourse satisfaction 3.7 +/- 4.81, and overall satisfaction 4.7 +/- 3.34. According to the classification of Cappelleri, of the 16 men who had had sexual intercourse during the previous month, 4 had no erectile dysfunction, 3 had mild, 4 mild to moderate, and 5 severe dysfunction. Erectile function was statistically related to the ability to maintain erections (mean IIEF score 4 and 5 for men with no erectile dysfunction versus a mean IIEF score of 4 and 5 for men with erectile dysfunction: 4.75 +/- 0.5 versus 2.00 +/- 1.32, P = 0.011 for IIEF score of 4 and 4.50 +/- 1.5 versus 3 +/- 2, P = 0.040 for IIEF score of 5). Young adult men with spina bifida and myelomeningocele begin sexual activity late. Moreover, 75% have erectile dysfunction that is related to difficulty in maintaining erections.

  4. Formation Mechanism of Self Assembled Horizontal ErSb Nanowires Embedded in a GaSb(001) Matrix

    Science.gov (United States)

    Wilson, Nathaniel; Kraemer, Stephan; PalmstrøM, Chris

    The ErxGa1-xSb exhibits a variety of self-assembling nanostructures. In order to harness these nanostructures for use in devices and other material systems it is important to understand their formation. We have characterized the growth mechanism of self-assembled horizontal ErSb nanowires in a GaSb(001) matrix through the use of in-situ Scanning Tunneling Microscopy (STM) as well as ex-situ Transmission Electron Microscopy (TEM). We observe large GaSb macrosteps on the growth surface of Er.3Ga.7Sb samples. The areas near the ledge and base of the macrosteps show significant differences in size and distribution of ErSb nanowires. Results suggest that the formation of macrosteps drives the transition from vertical to horizontal nanowires in the ErxGa1-xSb system. We also observe a low temperature growth mode, which results in horizontal nanowire formation under a wide range of flux conditions. This new growth mode does not exhibit the embedded growth observed in the formation of nanowires at higher temperatures and may allow for horizontal nanowire formation without the presence of macrosteps, as well as the formation of smaller nanoparticles which may be useful for achieving smaller nanoparticle dimensions and electron confinement effects. This work was supported by NSF-DMR under 1507875.

  5. Reactive ion etching of GaSb, (Al,Ga)Sb, and InAs for novel device applications

    International Nuclear Information System (INIS)

    LaTulipe, D.C.; Frank, D.J.; Munekata, H.

    1991-01-01

    Although a variety of novel device proposals for GaSb/(Al,Ga)Sb/InAs heterostructures have been made, relatively little is known about processing these materials. The authors of this paper have studied the reactive ion etching characteristics of GaSb, (Al,Ga)Sb, and InAs in both methane/hydrogen and chlorine gas chemistries. At conditions similar to those reported elsewhere for RIE of InP and GaAs in CH 4 /H 2 , the etch rate of (Al,Ga)Sb was found to be near zero, while GaSb and InAs etched at 200 Angstrom/minute. Under conditions where the etch mechanism is primarily physical sputtering, the three compounds etch at similar rates. Etching in Cl 2 was found to yield anistropic profiles, with the etch rate of (Al,Ga)Sb increasing with Al mole fraction, while InAs remains unetched. Damage to the InAs stop layer was investigated by sheet resistance and mobility measurements. These etching techniques were used to fabricate a novel InAs- channel FET composed of these materials. Several scanning electron micrographs of etching results are shown along with preliminary electrical characteristics

  6. Low dose epidemiology

    International Nuclear Information System (INIS)

    Tirmarche, M.; Hubert, P.

    1992-01-01

    Actually, epidemiological studies have to establish if the assessment of cancer risk can be verified at low chronic radiation doses. The population surveillance must be very long, the side effects and cancers of such radiation appearing much later. In France, this epidemiological study on nuclear workers have been decided recently. Before describing the experiment and french projects in epidemiology of nuclear workers, the authors present the main english and american studies

  7. Prenatal diagnosis of parapagus diprosopus dibrachius dipus twins with spina bifida in the first trimester using two- and three-dimensional ultrasound.

    Science.gov (United States)

    Yang, Pei-Yin; Wu, Ching-Hua; Yeh, Guang-Perng; Hsieh, Charles Tsung-Che

    2015-12-01

    Here, we report a case of parapagus diprosopus twins with spina bifida diagnosed in the first trimester of pregnancy using two-dimensional (2D) and three-dimensional (3D) ultrasound. A 28-year-old Taiwanese woman, gravid 1, para 0, visited our hospital due to an abnormal fetal head shape discovered by 2D ultrasound at 11-weeks gestation. Parapagus diprosopus twins with spina bifida were diagnosed after ultrasound examination. The characteristics of parapagus diprosopus twins are more illustrative in 3D ultrasound than in 2D ultrasound. After counseling, termination of pregnancy was chosen by the couple. Although necropsy was declined, the gross appearance and radiograph of the abortus confirmed our diagnosis. With the help of 3D ultrasound, we made an early and definitive diagnosis of conjoined twins. Copyright © 2015. Published by Elsevier B.V.

  8. 'Die verswygde storie': ’n gevallestudie oor die manifestasie van bates by ’n kleuter met spina bifida miëlomeningoseel

    Directory of Open Access Journals (Sweden)

    I. Eloff

    2007-07-01

    Full Text Available 'The unmentioned story': a case study of the manifestation of assets in a toddler with spina bifida miëlomeningoseel In South Africa a few major discourses with regard to disability can be distinguished. Although these discourses construct disability differently, three of them – the lay, charity and medical discourses – tend to view disability negatively. This article endeavours to challenge the stereotypical “picture” of a person with a disability. By conducting an intrinsic case study the unique intrapersonal assets of a boy (who has a physical disability, spina bifida is identified. An asset-based approach accompanied the research design as a theoretical framework in order to explore whether positive aspects of this boy’s life-world could be identified. This article identifies and embraces the positive side of living with a physical disability and illustrates ways in which positive constructions of an individual with disabilities can be pursued.

  9. Chemical consequences of the neutron irradiation of ionic antimony oxides and Fe Sb2O4

    Energy Technology Data Exchange (ETDEWEB)

    Facetti, J F [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

    1970-01-01

    The chemical consequences fo the neutron irradiation of ionic antimony oxides and Fe Sb2O4 are studied. The nature of the Sb-O2 bond effects the yield of SbV the higher the yield the more covalent the bond. In addition, the Fe Sb2O4 obeys the Maddock's rule.

  10. Oxidation of 1-butene over uranium oxide (UO3)-antimony oxide (Sb2O3) catalysts

    NARCIS (Netherlands)

    Simons, T.; Houtman, P.N.; Schuit, G.C.A.

    1971-01-01

    The oxidative dehydrogenation of butene to butadiene over U-Sb catalysts was investigated. The presence of two compds., (UO2)Sb3O7 and Sb3U3O14, reported by Grasselli and Callahan (1969), was confirmed with (UO2)Sb3O7 being the actual catalyst. The reaction is first order in butene and zero order in

  11. Increasing the thermoelectric power factor of Ge17Sb2Te20 by adjusting the Ge/Sb ratio

    Science.gov (United States)

    Williams, Jared B.; Mather, Spencer P.; Page, Alexander; Uher, Ctirad; Morelli, Donald T.

    2017-07-01

    We have investigated the thermoelectric properties of Ge17Sb2Te20. This compound is a known phase change material with electronic properties that depend strongly on temperature. The thermoelectric properties of this compound can be tuned by altering the stoichiometry of Ge and Sb without the use of additional foreign elements during synthesis. This tuning results in a 26% increase in the thermoelectric power factor at 723 K. Based on a single parabolic band model we show that the pristine material is optimally doped, and thus, a reduction in the lattice thermal conductivity of pure Ge17Sb2Te20 should result in an enhanced thermoelectric figure of merit.

  12. Study of conformational changes and protein aggregation of bovine serum albumin in presence of Sb(III) and Sb(V).

    Science.gov (United States)

    Verdugo, Marcelo; Ruiz Encinar, Jorge; Costa-Fernández, José Manuel; Menendez-Miranda, Mario; Bouzas-Ramos, Diego; Bravo, Manuel; Quiroz, Waldo

    2017-01-01

    Antimony is a metalloid that affects biological functions in humans due to a mechanism still not understood. There is no doubt that the toxicity and physicochemical properties of Sb are strongly related with its chemical state. In this paper, the interaction between Sb(III) and Sb(V) with bovine serum albumin (BSA) was investigated in vitro by fluorescence spectroscopy, and circular dichroism (CD) under simulated physiological conditions. Moreover, the coupling of the separation technique, asymmetric flow field-flow fractionation, with elemental mass spectrometry to understand the interaction of Sb(V) and Sb(III) with the BSA was also used. Our results showed a different behaviour of Sb(III) vs. Sb(V) regarding their effects on the interaction with the BSA. The effects in terms of protein aggregates and conformational changes were higher in the presence of Sb(III) compared to Sb(V) which may explain the differences in toxicity between both Sb species in vivo. Obtained results demonstrated the protective effect of GSH that modifies the degree of interaction between the Sb species with BSA. Interestingly, in our experiments it was possible to detect an interaction between BSA and Sb species, which may be related with the presence of labile complex between the Sb and a protein for the first time.

  13. Sb{sub 7}Te{sub 3}/ZnSb multilayer thin films for high thermal stability and long data retention phase-change memory

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shiyu; Wu, Weihua [Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, Shanghai 201804 (China); Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, Shanghai 201804 (China); Song, Sannian; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Science, Shanghai 200050 (China)

    2017-04-15

    Highlights: • Sb{sub 7}Te{sub 3} (ST) provides a fast crystallization speed, low melting temperature. • The Sb{sub 7}Te{sub 3}/ZnSb films exhibits faster crystallization speed, high thermal stability. • The calculated temperature for 10-year data retention is about 127 {sup o}C. • The Sb{sub 7}Te{sub 3}/ZnSb multilayer configuration with low power consumption. - Abstract: Phase-change memory is regard as one of the most promising candidates for the next-generation non-volatile memory. In this work, we proposed a Sb{sub 7}Te{sub 3}/ZnSb multilayer thin films to improve the thermal stability of Sb-rich Sb{sub 3}Te{sub 7}. The sheet resistance ratio between amorphous and crystalline states reached up to 4 orders of magnitude. With regard to the thermal stability, the calculated temperature for 10-year data retention is about 127 °C. The threshold current and threshold voltage of a cell based on Sb{sub 7}Te{sub 3}/ZnSb are 6.9 μA and 1.9 V, respectively. The lower RESET power is presented in the PCM cells of Sb{sub 7}Te{sub 3}/ZnSb films, benefiting from its high resistivity.

  14. Phase transformation in Mg—Sb3Te thin films

    International Nuclear Information System (INIS)

    Li Jun-Jian; Chen Yi-Min; Nie Qiu-Hua; Lü Ye-Gang; Wang Guo-Xiang; Shen Xiang; Dai Shi-Xun; Xu Tie-Feng

    2014-01-01

    Mg-doped Sb 3 Te films are proposed to improve the performance of phase-change memory (PCM). We prepare Mg-doped Sb 3 Te films and investigate their crystallization behaviors, structural, optical and electrical properties. We find that Mg-doping can increase the crystallization temperature, enhance the activation energy, and improve the 10-year data retention of Sb 3 Te. Especially Mg 25.19 (Sb 3 Te)74.81 shows higher T c (∼ 190 °C) and larger E a (∼ 3.49 eV), which results in a better data retention maintaining for 10 yr at ∼ 112 °C. Moreover R a /R c value is also improved. These excellent properties make Mg—Sb—Te material a promising candidate for the phase-change memory (PCM). (special topic — international conference on nanoscience and technology, china 2013)

  15. The crystal structure of ferdowsiite Ag8Sb4(As,Sb)4S16 and its relations to other ABX2 (A=Ag; B=As,Sb,Bi; X=S,Se) structures

    DEFF Research Database (Denmark)

    Makovicky, Emil; Topa, Dan

    2014-01-01

    arsenic. The crystal structure of ferdowsiite is a superstructure of a PbS like motif. The {100} planes of the PbS-like substructure are the (105̅), (301) and (010) planes in terms of the ferdowsiite lattice. The structure contains zig-zag chains of Sb1 connected via short Sb-S bonds and flanked by (Sb...

  16. A Novel Occulta-Type Spina Bifida Mediated by Murine Double Heterozygotes EphA2 and EphA4 Receptor Tyrosine Kinases

    Directory of Open Access Journals (Sweden)

    Nor Linda Abdullah

    2017-12-01

    Full Text Available Members of the Eph receptor tyrosine kinase have previously been implicated in cranial neural tube development. Failure of neural tube closure leads to the devastating conditions known as anencephaly and spina bifida. EphA2 and EphA4 are expressed at the tips of the closing spinal neural folds prior and during neural tube closure. We investigated the possible role of murine EphA2 and EphA4 during the last step of primary neural tube closure, which is adhesion and fusion. The individual mouse knockouts of EphA2 and EphA4 per se do not exhibit neural tube defects (NTDs. The embryos generated by the crossing of double heterozygotes Epha2tm1Jrui/+Epha4rb-2J/+ displayed NTDs with a wide degree of severity including close exencephaly and close spina bifida (spina bifida occulta. Interestingly, mutants displaying NTDs had skin covering the underlying lesion. The tissue sections revealed the elevated neural folds had not adhered and fused. The phenotypes seen in Epha2tm1Jrui/+Epha4rb-2J/+ double heterozygous embryos suggest both genes play a compensatory role with each other in the adhesion and fusion of the neural tube. In this study, there exists a >50% penetrance of NTDs in the mouse mutants, which genetically have a single allele each of EphA2 and EphA4 absent.

  17. Modeling of InGaSb thermophotovoltaic cells and materials

    Energy Technology Data Exchange (ETDEWEB)

    Zierak, M.; Borrego, J.M.; Bhat, I.; Gutmann, R.J. [Rensselaer Polytechnic Inst., Troy, NY (United States); Charache, G. [Lockheed Martin, Inc., Schenectady, NY (United States)

    1997-05-01

    A closed form computer program has been developed for the simulation and optimization of In{sub x}Ga{sub 1{minus}x}Sb thermophotovoltaic cells operating at room temperature. The program includes material parameter models of the energy bandgap, optical absorption constant, electron and hole mobility, intrinsic carrier concentration and index of refraction for any composition of GaInSb alloys.

  18. Fermi surface study of CeSb

    International Nuclear Information System (INIS)

    Aoki, H.; Crabtree, G.W.; Joss, W.; Hulliger, F.

    1984-09-01

    A Fermi surface study of the ferromagnetic phase of CeSb is presented. The γ frequency branches arising from the electron surfaces at the X points, three separate frequency branches from the hole surfaces at the GAMMA point and the low frequency branch α have been observed. The effective mass ratios are low and range from approx. 0.2 for the α branch to approx. 1.0 for the high frequency branch of γ. The low effective mass ratios suggest that the admixture of the conduction states with the f state is small. We have observed a drastic change in the appearance of the dHvA signal at the phase transition between the ferromagnetic and lower field antiferromagnetic phases: The low frequency α oscillation suddenly disappears as the crystal enters the antiferromagnetic phase. By utilizing the change in the signal appearance, the transition field strength has been measured as a function of the field direction. The present experimental results, particularly the origin of the α oscillation, are discussed in the light of the p-f mixing theory and recent band structure calculations based on localized f orbitals

  19. Fermi surface study of CeSb

    International Nuclear Information System (INIS)

    Aoki, H.; Crabtree, G.; Joss, W.; Hulliger, F.

    1985-01-01

    A Fermi surface study of the ferromagnetic phase of CeSb is presented. The γ frequency branches arising from the electron surfaces at the X points, three separate frequency branches from the hole surfaces at the GAMMA point, and the low-frequency branch α have been observed. The effective mass ratios are low and range from approx.0.2 for the α branch to approx.1.0 for the high-frequency branch of γ. The low effective mass ratios suggest that the admixture of the conduction states with the f state is small. We have observed a drastic change in the appearance of the de Haas--van Alpen signal at the phase transition between the ferromagnetic and lower field antiferromagnetic phases: the low-frequency α oscillation suddenly disappears as the crystal enters the antiferromagnetic phase. By utilizing the change in the signal appearance, the transition field strength has been measured as a function of the field direction. The present experimental results particularly the origin of the α oscillation, are discussed in the light of the p-f mixing theory and recent band-structure calculations based on localized f orbitals

  20. GaSb and GaSb/AlSb Superlattice Buffer Layers for High-Quality Photodiodes Grown on Commercial GaAs and Si Substrates

    Science.gov (United States)

    Gutiérrez, M.; Lloret, F.; Jurczak, P.; Wu, J.; Liu, H. Y.; Araújo, D.

    2018-05-01

    The objective of this work is the integration of InGaAs/GaSb/GaAs heterostructures, with high indium content, on GaAs and Si commercial wafers. The design of an interfacial misfit dislocation array, either on GaAs or Si substrates, allowed growth of strain-free devices. The growth of purposely designed superlattices with their active region free of extended defects on both GaAs and Si substrates is demonstrated. Transmission electron microscopy technique is used for the structural characterization and plastic relaxation study. In the first case, on GaAs substrates, the presence of dopants was demonstrated to reduce several times the threading dislocation density through a strain-hardening mechanism avoiding dislocation interactions, while in the second case, on Si substrates, similar reduction of dislocation interactions is obtained using an AlSb/GaSb superlattice. The latter is shown to redistribute spatially the interfacial misfit dislocation array to reduce dislocation interactions.

  1. Thermoelectric properties of ZnSb films grown by MOCVD

    International Nuclear Information System (INIS)

    Venkatasubramanian, R.; Watko, E.; Colpitts, T.

    1997-04-01

    The thermoelectric properties of metallorganic chemical vapor deposited (MOCVD) ZnSb films are reported. The growth conditions necessary to obtain stoichiometric ZnSb films and the effects of various growth parameters on the electrical conductivity and Seebeck coefficients of the films are described. The as-grown ZnSb films are p-type. It was observed that the growth of thicker ZnSb films lead to improved carrier mobilities and lower free-carrier concentrations. The Seebeck coefficient of ZnSb films was found to rise rapidly at approximately 160 to 170 C, with peak Seebeck coefficients as high as 470 microV/K at 220 C. The various growth conditions, including the use of intentional dopants, to improve the Seebeck coefficients at room temperature and above, are discussed. A short annealing of the ZnSb films at temperatures of ∼ 200 C resulted in reduced free-carrier levels and higher Seebeck coefficients at 300 K. Finally, ZT values based on preliminary thermal conductivity measurements using the 3-ω method are reported

  2. The contribution of epidemiology

    NARCIS (Netherlands)

    Brandt, P. van den; Voorrips, L.; Hertz-Picciotto, I.; Shuker, D.; Boeing, H.; Speijers, G.; Guittard, C.; Kleiner, J.; Knowles, M.; Wolk, A.; Goldbohm, A.

    2002-01-01

    Epidemiologic studies directly contribute data on risk (or benefit) in humans as the investigated species, and in the full food intake range normally encountered by humans. This paper starts with introducing the epidemiologic approach, followed by a discussion of perceived differences between

  3. The system analysis of temperature and melting enthalpy of intermetallic compounds of antimony-lanthanoids system of Sb Ln, Sb2Ln composition

    International Nuclear Information System (INIS)

    Badalova, M.A.; Chamanova, M.; Dodkhoev, E.S.; Badalov, A.; Abdusalyamova, M.N.

    2015-01-01

    Present article is devoted to system analysis of temperature and melting enthalpy of intermetallic compounds of antimony-lanthanoids system of Sb Ln, Sb 2 Ln composition. The melting enthalpy was estimated. The temperature value was determined.

  4. Role of interlayer coupling for the power factor of CuSbS2 and CuSbSe2

    KAUST Repository

    Alsaleh, Najebah Mohammed Abdullah; Singh, Nirpendra; Schwingenschlö gl, Udo

    2016-01-01

    The electronic and transport properties of bulk and monolayer CuSbS2 and CuSbSe2 are determined by using density functional theory and semiclassical Boltzmann transport theory, in order to investigate the role of interlayer coupling for the thermoelectric properties. The calculated band gaps of the bulk compounds are in agreement with experiments and significantly higher than those of the monolayers, which thus show lower Seebeck coefficients. Since also the electrical conductivity is lower, the monolayers are characterized by lower power factors. Therefore, interlayer coupling is found to be essential for the excellent thermoelectric response of CuSbS2 and CuSbSe2, even though it is weak.

  5. Ferro electrical properties of GeSbTe thin films; Propiedades ferroelectricas de peliculas delgadas de GeSbTe

    Energy Technology Data Exchange (ETDEWEB)

    Gervacio A, J. J.; Prokhorov, E.; Espinoza B, F. J., E-mail: jgervacio@qro.cinvestav.m [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Juriquilla, 76230 Queretaro (Mexico)

    2011-07-01

    The aim of this work is to investigate and compare ferro electrical properties of thin GeSbTe films with composition Ge{sub 4}Sb{sub 1}Te{sub 5} (with well defined ferro electrical properties) and Ge{sub 2}Sb{sub 2}Te{sub 5} using impedance, optical reflection, XRD, DSc and Piezo response Force Microscopy techniques. The temperature dependence of the capacitance in both materials shows an abrupt change at the temperature corresponding to ferroelectric-paraelectric transition and the Curie-Weiss dependence. In Ge{sub 2}Sb{sub 2}Te{sub 5} films this transition corresponds to the end from a NaCl-type to a hexagonal transformation. Piezo response Force Microscopy measurements found ferroelectric domains with dimension approximately equal to the dimension of grains. (Author)

  6. Role of interlayer coupling for the power factor of CuSbS2 and CuSbSe2

    KAUST Repository

    Alsaleh, Najebah Mohammed Abdullah

    2017-01-08

    The electronic and transport properties of bulk and monolayer CuSbS2 and CuSbSe2 are determined by using density functional theory and semiclassical Boltzmann transport theory, in order to investigate the role of interlayer coupling for the thermoelectric properties. The calculated band gaps of the bulk compounds are in agreement with experiments and significantly higher than those of the monolayers, which thus show lower Seebeck coefficients. Since also the electrical conductivity is lower, the monolayers are characterized by lower power factors. Therefore, interlayer coupling is found to be essential for the excellent thermoelectric response of CuSbS2 and CuSbSe2, even though it is weak.

  7. Role of interlayer coupling for the power factor of CuSbS2 and CuSbSe2

    KAUST Repository

    Alsaleh, Najebah M.

    2016-09-26

    The electronic and transport properties of bulk and monolayer CuSbS2 and CuSbSe2 are determined by using density functional theory and semiclassical Boltzmann transport theory, in order to investigate the role of interlayer coupling for the thermoelectric properties. The calculated band gaps of the bulk compounds are in agreement with experiments and significantly higher than those of the monolayers, which thus show lower Seebeck coefficients. Since also the electrical conductivity is lower, the monolayers are characterized by lower power factors. Therefore, interlayer coupling is found to be essential for the excellent thermoelectric response of CuSbS2 and CuSbSe2, even though it is weak.

  8. Crystal structure, magnetism, {sup 89}Y solid state NMR, and {sup 121}Sb Moessbauer spectroscopic investigations of YIrSb

    Energy Technology Data Exchange (ETDEWEB)

    Benndorf, Christopher [Institut fuer Physikalische Chemie, Universitaet Muenster (Germany); Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster (Germany); Heletta, Lukas; Block, Theresa; Poettgen, Rainer [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster (Germany); Eckert, Hellmut [Institut fuer Physikalische Chemie, Universitaet Muenster (Germany); Institute of Physics in Sao Carlos, University of Sao Paulo, Sao Carlos (Brazil)

    2017-02-15

    The ternary antimonide YIrSb was synthesized from the binary precursor YIr and elemental antimony by a diffusion controlled solid-state reaction. Single crystals were obtained by a flux technique with elemental bismuth as an inert solvent. The YIrSb structure (TiNiSi type, space group Pnma) was refined from single-crystal X-ray diffractometer data: a = 711.06(9), b = 447.74(5), c = 784.20(8) pm, wR{sub 2} = 0.0455, 535 F{sup 2} values, 20 variables. {sup 89}Y solid state MAS NMR and {sup 121}Sb Moessbauer spectra show single resonance lines in agreement with single-crystal X-ray data. YIrSb is a Pauli paramagnet. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. AgSbSe2 and AgSb(S,Se)2 thin films for photovoltaic applications

    International Nuclear Information System (INIS)

    Garza, J.G.; Shaji, S.; Rodriguez, A.C.; Das Roy, T.K.; Krishnan, B.

    2011-01-01

    Silver antimony selenide (AgSbSe 2 ) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb 2 S 3 ), silver selenide (Ag 2 Se), selenium (Se) and silver (Ag). Sb 2 S 3 thin film was prepared from a chemical bath containing SbCl 3 and Na 2 S 2 O 3 , Ag 2 Se from a solution containing AgNO 3 and Na 2 SeSO 3 and Se thin films from an acidified solution of Na 2 SeSO 3 , at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10 -3 Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe 2 or AgSb(S,Se) 2 depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe 2 /Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V oc = 435 mV and J sc = 0.08 mA/cm 2 under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe 2 as an absorber material by a non-toxic selenization process is achieved.

  10. InAs/GaSb/AlSb composite quantum well structure preparation with help of reflectance anisotropy spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Hospodková, Alice; Hulicius, Eduard; Pangrác, Jiří; Dominec, Filip; Mikhailova, M. P.; Veinger, A.I.; Kochman, I.V.

    2017-01-01

    Roč. 464, Apr (2017), s. 206-210 ISSN 0022-0248 R&D Projects: GA MŠk LM2015087; GA MŠk LO1603 Institutional support: RVO:68378271 Keywords : low dimensional structures * MOVPE * InAs/GaSb composite quantum wells * AlSb Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.751, year: 2016

  11. AgSbSe{sub 2} and AgSb(S,Se){sub 2} thin films for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garza, J.G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Rodriguez, A.C.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2011-10-01

    Silver antimony selenide (AgSbSe{sub 2}) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb{sub 2}S{sub 3}), silver selenide (Ag{sub 2}Se), selenium (Se) and silver (Ag). Sb{sub 2}S{sub 3} thin film was prepared from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}, Ag{sub 2}Se from a solution containing AgNO{sub 3} and Na{sub 2}SeSO{sub 3} and Se thin films from an acidified solution of Na{sub 2}SeSO{sub 3}, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10{sup -3} Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe{sub 2} or AgSb(S,Se){sub 2} depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe{sub 2}/Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V{sub oc} = 435 mV and J{sub sc} = 0.08 mA/cm{sup 2} under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe{sub 2} as an absorber material by a non-toxic selenization process is achieved.

  12. Optimization of growth parameters for MOVPE-grown GaSb and Ga1−xInxSb

    International Nuclear Information System (INIS)

    Miya, S.S.; Wagener, V.; Botha, J.R.

    2012-01-01

    The triethylgallium/trimethylantimony (TEGa/TMSb) precursor combination was used for the metal-organic vapour phase epitaxial growth of GaSb at a growth temperature of 520 °C at atmospheric pressure. Trimethylindium was added in the case of Ga 1−x In x Sb growth. The effects of group V flux to group III flux ratio (V/III ratio) on the crystallinity and optical properties of GaSb layers are reported. It has been observed from the crystalline quality and optical properties that nominal V/III ratios of values greater than unity are required for GaSb epitaxial layers grown at this temperature. It has also been shown that Ga 1−x In x Sb can be grown using TEGa as a source of gallium species at atmospheric pressure. The relationship between Ga 1−x In x Sb vapour composition and solid composition has been studied at a V/III ratio of 0.78.

  13. Photoluminescence and structural properties of unintentional single and double InGaSb/GaSb quantum wells grown by MOVPE

    Science.gov (United States)

    Ahia, Chinedu Christian; Tile, Ngcali; Botha, Johannes R.; Olivier, E. J.

    2018-04-01

    The structural and photoluminescence (PL) characterization of InGaSb quantum well (QW) structures grown on GaSb substrate (100) using atmospheric pressure Metalorganic Vapor Phase Epitaxy (MOVPE) is presented. Both structures (single and double-InGaSb QWs) were inadvertently formed during an attempt to grow capped InSb/GaSb quantum dots (QDs). In this work, 10 K PL peak energies at 735 meV and 740 meV are suggested to be emissions from the single and double QWs, respectively. These lines exhibit red shifts, accompanied by a reduction in their full-widths at half-maximum (FWHM) as the excitation power decreases. The presence of a GaSb spacer in the double QW was found to increase the strength of the PL emission, which consequently gives rise to a reduced blue-shift and broadening of the PL emission line observed for the double QW with an increase in laser power, while the low thermal activation energy for the quenching of the PL from the double QW is attributed to the existence of threading dislocations, as seen in the bright field TEM image for this sample.

  14. New Insights into the Origins of Sb-Induced Effects on Self-Catalyzed GaAsSb Nanowire Arrays.

    Science.gov (United States)

    Ren, Dingding; Dheeraj, Dasa L; Jin, Chengjun; Nilsen, Julie S; Huh, Junghwan; Reinertsen, Johannes F; Munshi, A Mazid; Gustafsson, Anders; van Helvoort, Antonius T J; Weman, Helge; Fimland, Bjørn-Ove

    2016-02-10

    Ternary semiconductor nanowire arrays enable scalable fabrication of nano-optoelectronic devices with tunable bandgap. However, the lack of insight into the effects of the incorporation of Vy element results in lack of control on the growth of ternary III-V(1-y)Vy nanowires and hinders the development of high-performance nanowire devices based on such ternaries. Here, we report on the origins of Sb-induced effects affecting the morphology and crystal structure of self-catalyzed GaAsSb nanowire arrays. The nanowire growth by molecular beam epitaxy is changed both kinetically and thermodynamically by the introduction of Sb. An anomalous decrease of the axial growth rate with increased Sb2 flux is found to be due to both the indirect kinetic influence via the Ga adatom diffusion induced catalyst geometry evolution and the direct composition modulation. From the fundamental growth analyses and the crystal phase evolution mechanism proposed in this Letter, the phase transition/stability in catalyst-assisted ternary III-V-V nanowire growth can be well explained. Wavelength tunability with good homogeneity of the optical emission from the self-catalyzed GaAsSb nanowire arrays with high crystal phase purity is demonstrated by only adjusting the Sb2 flux.

  15. Gel-combustion synthesis of CoSb2O6 and its reduction to powdery Sb2Co alloy

    Directory of Open Access Journals (Sweden)

    MAJA JOVIC

    2009-01-01

    Full Text Available Sb2Co alloy in powdery form was synthesized via reduction with gaseous hydrogen of the oxide CoSb2O6, obtained by the citrate gel-combustion technique. The precursor was an aqueous solution of antimony nitrate, cobalt nitrate and citric acid. The precursor solution with mole ratio Co(II/Sb(V of 1:2 was gelatinized by evaporation of water. The gel was heated in air up to the temperature of self-ignition. The product of gel combustion was a mixture of oxides and it had to be additionally thermally treated in order to be converted to pure CoSb2O6. The reduction of CoSb2O6 by gaseous hydrogen yielded powdery Sb2Co as the sole phase. The process of oxide reduction to alloy was controlled by thermogravimetry, while X-ray diffractometry was used to control the phase compositions of both the oxides and alloys.

  16. Epitaxial Growth and Electronic Structure of Half Heuslers Co1-xNixTiSb (001), Ni1-xCoxTiSn, and PtLuSb

    Science.gov (United States)

    2016-01-09

    lineup of CoTiSb with conventional III/V’s, the valence-band discontinuities in abrupt CoTiSb/InGaAs(001) and CoTiSb/InAlAs(001) heterojunctions were...confirm identification of a topological surface state: first, the state must be confined and show no out-of-plane dispersion; second, the state

  17. WHO - IPHECA: Epidemiological aspects

    International Nuclear Information System (INIS)

    Souchkevitch, G.

    1996-01-01

    In May 1991 the World Health Assembly endorsed the establishment of the International Programme on the Health Effects of the Chernobyl Accident (IPHECA) under the auspices of WHO. Five pilot projects have been carried out within IPHECA in the study territories of Belarus, Russian Federation and Ukraine in a period from 1991 to 1994. This pilot projects dealt with the detection and treatment of leukaemia and related diseases (Haematology Project), thyroid disorders (Thyroid project), brain damage during exposure 'in-utero' (Brain Damage 'in-Utero' project) and with the development of the Chernobyl registries (Epidemiological Registry Project). A fifth pilot project on oral health was performed only in Belarus. Epidemiological investigations have been an important component of all IPHECA pilot projects. Within 'Epidemiological Registry' Project such investigations have been the principal activity. But with respect to other IPHECA projects it was carried out in addition to main objectives relating to medical monitoring, early diagnosis and treatment of specific diseases included in project protocols. To support the epidemiological investigations within IPHECA, WHO supplied 41 computers in Belarus, Russian Federation and Ukraine and provided training for specialists from these countries in internationally recognized centres. The training programmes and host countries were as follows: standardization of epidemiological investigations (United Kingdom), radiation epidemiology (Russia), development of software (United Kingdom), principles of epidemiological investigations (The Czech Republic), cohort investigations (Japan)

  18. WHO - IPHECA: Epidemiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Souchkevitch, G [World Health Organization, Geneva (Swaziland)

    1996-07-01

    In May 1991 the World Health Assembly endorsed the establishment of the International Programme on the Health Effects of the Chernobyl Accident (IPHECA) under the auspices of WHO. Five pilot projects have been carried out within IPHECA in the study territories of Belarus, Russian Federation and Ukraine in a period from 1991 to 1994. This pilot projects dealt with the detection and treatment of leukaemia and related diseases (Haematology Project), thyroid disorders (Thyroid project), brain damage during exposure 'in-utero' (Brain Damage 'in-Utero' project) and with the development of the Chernobyl registries (Epidemiological Registry Project). A fifth pilot project on oral health was performed only in Belarus. Epidemiological investigations have been an important component of all IPHECA pilot projects. Within 'Epidemiological Registry' Project such investigations have been the principal activity. But with respect to other IPHECA projects it was carried out in addition to main objectives relating to medical monitoring, early diagnosis and treatment of specific diseases included in project protocols. To support the epidemiological investigations within IPHECA, WHO supplied 41 computers in Belarus, Russian Federation and Ukraine and provided training for specialists from these countries in internationally recognized centres. The training programmes and host countries were as follows: standardization of epidemiological investigations (United Kingdom), radiation epidemiology (Russia), development of software (United Kingdom), principles of epidemiological investigations (The Czech Republic), cohort investigations (Japan)

  19. Basic concepts of epidemiology

    International Nuclear Information System (INIS)

    Savitz, D.A.

    1984-01-01

    Epidemiology can be defined simply as the science of the distribution and determinants of disease in human populations. As a descriptive tool, epidemiology can aid health care service providers, for example, in allocation of resources. In its analytic capacity, the epidemiologic approach can help identify determinants of disease through the study of human populations. Epidemiology is primarily an observational rather than experimental methodology, with corresponding strengths and limitations. Relative to other approaches for assessing disease etiology and impacts of potential health hazards, epidemiology has a rather unique role that is complementary to, but independent of, both basic biologic sciences and clinical medicine. Experimental biologic sciences such as toxicology and physiology provide critical information on biologic mechanisms of disease required for causal inference. Clinical medicine often serves as the warning system that provides etiologic clues to be pursued through systematic investigation. The advantage of the epidemiologic approach is its reliance on human field experience, that is, the real world. While laboratory experimentation is uniquely well suited to defining potential hazards, it can neither determine whether human populations have actually been affected nor quantify that effect. Building all the complexities of human behavior and external factors into a laboratory study or mathematical model is impossible. By studying the world as it exists, epidemiology examines the integrated, summarized product of the myriad factors influencing health

  20. Epidemiology: Then and Now.

    Science.gov (United States)

    Kuller, Lewis H

    2016-03-01

    Twenty-five years ago, on the 75th anniversary of the Johns Hopkins Bloomberg School of Public Health, I noted that epidemiologic research was moving away from the traditional approaches used to investigate "epidemics" and their close relationship with preventive medicine. Twenty-five years later, the role of epidemiology as an important contribution to human population research, preventive medicine, and public health is under substantial pressure because of the emphasis on "big data," phenomenology, and personalized medical therapies. Epidemiology is the study of epidemics. The primary role of epidemiology is to identify the epidemics and parameters of interest of host, agent, and environment and to generate and test hypotheses in search of causal pathways. Almost all diseases have a specific distribution in relation to time, place, and person and specific "causes" with high effect sizes. Epidemiology then uses such information to develop interventions and test (through clinical trials and natural experiments) their efficacy and effectiveness. Epidemiology is dependent on new technologies to evaluate improved measurements of host (genomics), epigenetics, identification of agents (metabolomics, proteomics), new technology to evaluate both physical and social environment, and modern methods of data collection. Epidemiology does poorly in studying anything other than epidemics and collections of numerators and denominators without specific hypotheses even with improved statistical methodologies. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Ab Initio Molecular Dynamics Studies of Pb m Sb n ( m + n ≤ 9) Alloy Clusters

    Science.gov (United States)

    Song, Bingyi; Xu, Baoqiang; Yang, Bin; Jiang, Wenlong; Chen, Xiumin; Xu, Na; Liu, Dachun; Dai, Yongnian

    2017-10-01

    Structure, stability, and dynamics of Pb m Sb n ( m + n ≤ 9) clusters were investigated using ab initio molecular dynamics. Size dependence of binding energies, the second-order energy difference of clusters, dissociation energy, HOMO-LUMO gaps, Mayer bond order, and the diffusion coefficient of Pb m Sb n clusters were discussed. Results suggest that Pb3Sb2, Pb4Sb2, and Pb5Sb4 ( n = 2 or 4) clusters have higher stability than other clusters, which is consistent with previous findings. In case of Pb-Sb alloy, the dynamics results show that Pb4Sb2 (Pb-22.71 wt pct Sb) can exist in gas phase at 1073 K (800 °C), which reasonably explains the azeotropic phenomenon, and the calculated values are in agreement with the experimental results (Pb-22 wt pct Sb).

  2. Epidemiology and Radiation Protection

    International Nuclear Information System (INIS)

    1987-01-01

    Epidemiology aims at providing direct evidence of the long term health effects in humans due to potentially dangerous exposures to various nuisance agents, including ionising radiation. Inappropriate interpretation and use of the results of epidemiological studies may result in inaccurate assessments of the risks associated with radiation exposure. This report presents the proceedings of a Workshop organised by the NEA to create an opportunity for epidemiologists and radiation protection specialists to exchange their experiences and views on the problems of methodology in epidemiological research and on the application of its results to the assessment of radiation risks

  3. First-principles study of amorphous Ga4Sb6Te3 phase-change alloys

    Science.gov (United States)

    Bouzid, Assil; Gabardi, Silvia; Massobrio, Carlo; Boero, Mauro; Bernasconi, Marco

    2015-05-01

    First-principles molecular dynamics simulations within the density functional theory framework were performed to generate amorphous models of the Ga4Sb6Te3 phase change alloy by quenching from the melt. We find that Ga-Sb and Ga-Te are the most abundant bonds with only a minor amount of Sb-Te bonds participating to the alloy network. Ga and four-coordinated Sb atoms present a tetrahedral-like geometry, whereas three-coordinated Sb atoms are in a pyramidal configuration. The tetrahedral-like geometries are similar to those of the crystalline phase of the two binary compounds GaTe and GaSb. A sizable fraction of Sb-Sb bonds is also present, indicating a partial nanoscale segregation of Sb. Despite the fact that the composition Ga4Sb6Te3 lies on the pseudobinary Ga Sb -Sb2Te3 tie line, the amorphous network can be seen as a mixture of the two binary compounds GaTe and GaSb with intertwined elemental Sb.

  4. Sb interactions with TaC precipitates and Cu in ion-implanted α-Fe

    International Nuclear Information System (INIS)

    Follstaedt, D.M.; Myers, S.M.

    1980-01-01

    The interactions of Sb with the other species implanted into Fe to form Fe-Ta-C-Sb and Fe-Cu-Sb alloys have been examined with transmission electron microscopy and Rutherford backscattering following annealing at 873 0 K. Trapping of Sb at TaC precipitates is observed in the former alloy just as was previously observed in Fe-Ti-C-Sb. In Fe-Cu-Sb, Sb interactions are governed by the atomic ratio of Sb to Cu. For ratios between 0.2 to 0.4, the compound β-Cu 3 Sb was observed to form. For Sb to Cu ratios approx.< 0.1, fcc Cu precipitates were observed. In addition to the expected Sb dissolution in Cu, Sb trapping by Cu precipitates is also observed. The binding enthalpy of Sb at both TaC and Cu precipitates with respect to a solution site in the bcc Fe is the same as observed for TiC, approx. 0.4 eV. The constancy of the binding enthalpy at such chemically dissimilar precipitates supports the hypothesis that the trapping is due to the structural discontinuity of the precipitate-host interface. The observed Sb trapping at precipitates is of potential significance for the control of temper embrittlement in bcc steels

  5. Crystal structure and bonding characteristics of In-doped β-Zn4Sb3

    International Nuclear Information System (INIS)

    Tang, Dingguo; Zhao, Wenyu; Cheng, Sudan; Wei, Ping; Yu, Jian; Zhang, Qingjie

    2012-01-01

    The effects of indium impurity on the crystal structure and bonding characteristics of In-doped β-Zn 4 Sb 3 were investigated by powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD Rietveld refinement indicates that the indium impurity preferentially substitutes one of Sb atoms in Sb–Sb dimer at the 12c Sb(2) site and simultaneously leads to the increase of Zn occupancy. The observations of binding energy shift and a new valence state in Sb 3d core-level XPS spectra can be attributed to the charge transfer from In and Zn to Sb. As a result, more electropositive Zn atoms are needed to maintain the charge balance. The reduction of the lattice thermal conductivity is ascribed to the formation of the asymmetric Sb–In bond, resulting in much low lattice thermal conductivity of 0.49 W −1 K −1 of Zn 4 Sb 2.96 In 0.04 . - Graphical abstract: The indium impurity substitutes one of Sb atoms in Sb–Sb dimer, resulting the charge transfer from In to Sb, which leads to the binding energy of Sb 3d core level XPS spectra shift to low value. Highlights: ► The indium impurity preferentially substitutes one of Sb atoms in Sb–Sb dimer at the 12c Sb(2) site. ► The occupancy of Zn increases by the In substitution for Sb, whereas that of Sb keeps constant. ► The binding energy of Sb 3d shifts to low value. ► The charge transfer occurs from In and Zn to Sb.

  6. Phase equilibria melt-solid in the systems Pb-InSb-CaSb and Pb-InCs-GaAs

    International Nuclear Information System (INIS)

    Grebenyuk, A.M.; Charykov, N.A.; Puchkov, L.V.

    1992-01-01

    Results of experimental investigation and thermodynamic calculation of fusibility curves of Pb-InSb-GaSb and Pb-InAs-GaAs thernary systems, which haven't been investigated earlier, are presented. Fusibility curves of Pb-InSb-GaSb and Pb-InAs-GaAs systems contain two crystallization fields: solid solutions of In x Ga 1-x Sb and Pb, In x Ga 1-x As and Pb. The latter fields are retained against Pb figurative point and conform to 582 K < T < 593 K crystallization temperatures

  7. Electronic and magnetic properties of SmCrSb3 and GdCrSb3: A first principles study

    International Nuclear Information System (INIS)

    Sandeep; Ghimire, M.P.; Thapa, R.K.

    2011-01-01

    The density of states (DOS) and the magnetic moments of SmCrSb 3 and GdCrSb 3 have been studied by first principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). For the exchange-correlation potential, the local-spin density approximations with correlation energy (LSDA+U) method have been used. Total and partial DOS have been computed using the WIEN2k code. DOS result shows the exchange-splittings of Cr-3d and rare-earth (R) 4f states electrons, which are responsible for the ground state ferromagnetic (FM) behavior of the systems. The FM behavior of these systems is strongly influenced by the average number of Cr-3d and Sm (Gd) 4f-electrons. The effective moment of SmCrSb 3 is found to be 7.07 μ B while for GdCrSb 3 it is 8.27 μ B . The Cr atom plays a significant role on the magnetic properties due to the hybridization between Cr-3d and Sb-5p states. - Highlights: → DOS and the magnetic moments of SmCrSb 3 and GdCrSb 3 are studied by full-FP-LAPW method. → Exchange splitting of eg and t2g of Cr-3d states and the rare-earth 4f state electrons are responsible for ground state ferromagnetism. → Rare-earth magnetic moments are greater than Cr moment indicating presence of 4f states.

  8. Large subcapsular hematoma following ureteroscopic laser lithotripsy of renal calculi in a spina bifida patient: lessons we learn

    Directory of Open Access Journals (Sweden)

    Vaidyanathan S

    2016-08-01

    Full Text Available Subramanian Vaidyanathan,1 Azi Samsudin,2 Gurpreet Singh,3 Peter L Hughes,4 Bakul M Soni,1 Fahed Selmi1 1Regional Spinal Injuries Center, Southport and Formby District General Hospital, Southport, UK; 2Department of Urology, Whiston Hospital, Prescot, UK; 3Department of Urology, 4Department of Radiology, Southport and Formby District General Hospital, Southport, UK Introduction: Paraplegic patients are at greater risk of developing complications following ureteroscopic lithotripsy because of urine infection associated with neuropathic bladder, difficulties in access due to altered anatomy of urinary bladder and urethra, spinal curvature, spasticity, and contractures. We report the occurrence of large subcapsular hematoma following ureteroscopy and discuss lessons we learn from this case.Case report: A 48-year-old male patient with spina bifida underwent ureteroscopy with laser lithotripsy and ureteric stenting for left ureteric stone and staghorn calculus with hydronephrosis; laser lithotripsy was repeated after 3 months; both procedures were performed by a senior urologist and did not result in any complications. Ureteroscopic laser lithotripsy was performed 5 months later by a urological trainee; it was difficult to negotiate the scope as vision became poor because of bleeding (as a result of the procedure. Postoperatively, hematuria persisted; temperature was 39°C. Cefuroxime was given intravenously followed by gentamicin for 5 days; hematuria subsided gradually; he was discharged home. Ten days later, this patient developed temperature, the urine culture grew Pseudomonas aeruginosa, and ciprofloxacin was given orally. Computed tomography (CT of the urinary tract, performed 4 weeks after ureteroscopy, revealed a 9×7 cm subcapsular collection on the left kidney compressing underlying parenchyma. Percutaneous drainage was not feasible because of severe curvature of spine. Isotope renogram revealed deterioration in left renal function from 30

  9. Quaternary InGaAsSb Thermophotovoltaic Diodes

    International Nuclear Information System (INIS)

    MW Dashiell; JF Beausang; H Ehsani; GJ Nichols; DM Depoy; LR Danielson; P Talamo; KD Rahner; EJ Brown; SR Burger; PM Foruspring; WF Topper; PF Baldasaro; CA Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; J Li; R Martinelli; D Donetski; S Anikeev; G Belenky; S Luryi

    2006-01-01

    In x Ga 1-x As y Sb 1-y thermophotovoltaic (TPV) diodes were grown lattice-matched to GaSb substrates by Metal Organic Vapor Phase Epitaxy (MOVPE) in the bandgap range of E G = 0.5 to 0.6eV. InGaAsSb TPV diodes, utilizing front-surface spectral control filters, are measured with thermal-to-electric conversion efficiency and power density of η TPV = 19.7% and PD =0.58 W/cm 2 respectively for a radiator temperature of T radiator = 950 C, diode temperature of T diode = 27 C, and diode bandgap of E G = 0.53eV. Practical limits to TPV energy conversion efficiency are established using measured recombination coefficients and optical properties of front surface spectral control filters, which for 0.53eV InGaAsSb TPV energy conversion is η TPV = 28% and PD = 0.85W/cm 2 at the above operating temperatures. The most severe performance limits are imposed by (1) diode open-circuit voltage (VOC) limits due to intrinsic Auger recombination and (2) parasitic photon absorption in the inactive regions of the module. Experimentally, the diode V OC is 15% below the practical limit imposed by intrinsic Auger recombination processes. Analysis of InGaAsSb diode electrical performance vs. diode architecture indicate that the V OC and thus efficiency is limited by extrinsic recombination processes such as through bulk defects

  10. Characterization of midwave infrared InSb avalanche photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Abautret, J., E-mail: johan.abautret@ies.univ-montp2.fr; Evirgen, A. [Université Montpellier, IES, UMR 5214, F-34095 Montpellier (France); CNRS, IES, UMR 5214, F-34095 Montpellier (France); SOFRADIR, BP 21, 38113 Veurey-Voroize (France); Perez, J. P.; Christol, P. [Université Montpellier, IES, UMR 5214, F-34095 Montpellier (France); CNRS, IES, UMR 5214, F-34095 Montpellier (France); Rothman, J. [CEA-LETI, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Cordat, A. [SOFRADIR, BP 21, 38113 Veurey-Voroize (France)

    2015-06-28

    This paper focuses on the InSb material potential for the elaboration of Avalanche Photodiodes (APD) for high performance infrared imaging applications, both in passive or active mode. The first InSb electron-APD structure was grown by molecular beam epitaxy, processed and electrically characterized. The device performances are at the state of the art for the InSb epi-diode technology, with a dark current density J(−50 mV) = 32 nA/cm{sup 2} at 77 K. Then, a pure electron injection was performed, and an avalanche gain, increasing exponentially, was observed with a gain value near 3 at −4 V at 77 K. The Okuto–Crowell model was used to determine the electron ionization coefficient α(E) in InSb, and the InSb gain behavior is compared with the one of InAs and MCT APDs.

  11. (Ga,Fe)Sb: A p-type ferromagnetic semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Nguyen Thanh; Anh, Le Duc; Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Hai, Pham Nam [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-0033 (Japan)

    2014-09-29

    A p-type ferromagnetic semiconductor (Ga{sub 1−x},Fe{sub x})Sb (x = 3.9%–13.7%) has been grown by low-temperature molecular beam epitaxy (MBE) on GaAs(001) substrates. Reflection high energy electron diffraction patterns during the MBE growth and X-ray diffraction spectra indicate that (Ga,Fe)Sb layers have the zinc-blende crystal structure without any other crystallographic phase of precipitates. Magnetic circular dichroism (MCD) spectroscopy characterizations indicate that (Ga,Fe)Sb has the zinc-blende band structure with spin-splitting induced by s,p-d exchange interactions. The magnetic field dependence of the MCD intensity and anomalous Hall resistance of (Ga,Fe)Sb show clear hysteresis, demonstrating the presence of ferromagnetic order. The Curie temperature (T{sub C}) increases with increasing x and reaches 140 K at x = 13.7%. The crystal structure analyses, magneto-transport, and magneto-optical properties indicate that (Ga,Fe)Sb is an intrinsic ferromagnetic semiconductor.

  12. Cancer Epidemiology Cohorts

    Science.gov (United States)

    Cohort studies are fundamental for epidemiological research by helping researchers better understand the etiology of cancer and provide insights into the key determinants of this disease and its outcomes.

  13. Epidemiology & Genomics Research Program

    Science.gov (United States)

    The Epidemiology and Genomics Research Program, in the National Cancer Institute's Division of Cancer Control and Population Sciences, funds research in human populations to understand the determinants of cancer occurrence and outcomes.

  14. Investigation of InAs/GaSb-based superlattices by diffraction methods

    Energy Technology Data Exchange (ETDEWEB)

    Ashuach, Y.; Kauffmann, Y.; Lakin, E. [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Zolotoyabko, E., E-mail: zloto@tx.technion.ac.i [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Grossman, S.; Klin, O.; Weiss, E. [SCD, SemiConductor Devices, P. O. Box 2250, Haifa 31021 (Israel)

    2010-02-15

    We use high-resolution X-ray diffraction and high-resolution transmission electron microscopy in order to study the strain state, atomic intermixing and layer thicknesses in the MBE-grown GaSb/InSb/InAs/InSb superlattices. Simple and fast metrology procedure is developed, which allows us to obtain the most important technological parameters, such as the thicknesses of the GaSb, InAs and ultra-thin InSb sub-layers, the superlattice period and the fraction of atomic substitutions in the InSb sub-layers.

  15. Syntheses, and crystal and electronic structures of the new Zintl phases Na2ACdSb2 and K2ACdSb2 (A=Ca, Sr, Ba, Eu, Yb): Structural relationship with Yb2CdSb2 and the solid solutions Sr2-xAxCdSb2, Ba2-xAxCdSb2 and Eu2-xYbxCdSb2

    International Nuclear Information System (INIS)

    Saparov, Bayrammurad; Saito, Maia; Bobev, Svilen

    2011-01-01

    Presented are the details of the syntheses, crystal and electronic structures of a new family of Zintl phases Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb), as well as the solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 and Eu 2-x Yb x CdSb 2 . The structures of Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) were determined to be of a new type with the non-centrosymmetric space group Pmc2 1 (no. 26), Pearson symbol oP12, with lattice parameters a=4.684(1)-4.788(1) A; b=9.099(3)-9.117(2) A; c=7.837(1)-8.057(2) A for the Na 2 ACdSb 2 series, and a=4.6637(9)-5.0368(8) A; b=9.100(2)-9.8183(15) A; and c=7.7954(15)-8.4924(13) A for K 2 ACdSb 2 , respectively. The solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 and Eu 2-x Yb x CdSb 2 (x∼1) are isostructural and isoelectronic to the recently reported Yb 2 CdSb 2 (space group Cmc2 1 (no. 36), Pearson symbol cP20). All discussed structures are based upon CdSb 2 4- polyanionic layers, similar to the ones observed in Yb 2 CdSb 2 , with various alkali- and/or alkaline-earth cations coordinated to them. Magnetic susceptibility and Seebeck coefficient measurements on selected Eu 2-x Yb x CdSb 2 samples, taken at low temperatures up to 300 K, are also reported. -- Graphical abstract: The quaternary Zintl phases Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) with novel layered structures have been synthesized for the first time and structurally characterized by single-crystal X-ray diffraction. Reported as well are the results from crystallographic and property studies of the closely related solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 (x∼1), and Eu 2-x Yb x CdSb 2 (1 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) are new quaternary Zintl phases. → Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 (x∼1), and Eu 2-x Yb x CdSb 2 (1 4 tetrahedra. → Eu 2-x Yb x CdSb 2 (1< x<2) exhibit high Seebeck coefficient (217 μV/K at RT).

  16. Super VHS video cassette recorder, A-SB88; Super VHS video A-SB88

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    A super VHS video cassette recorder, A-SB88, was commercialized having no compromised aspects at all in picture quality, sound quality, operability, energy conservation, design, etc. In the picture quality, the VCR is mounted with the S-ET system capable of realizing a quality comparable to SVHS with a three-dimensional Y/C detached circuit for dynamic moving image detection, three-dimensional DNR(digital noise reduction) and TBC(time base corrector), FE(flying erase) circuit, and a normal tape. In the operability, it is provided with a remote control transfer in large LCD, 400x high speed rewind, reservation system capable of simply reserving a serial drama for example, and a function for searching the end of picture recording; also, in the environmental aspect, the stand-by power consumption was reduced to 1/10 of conventional models (ratio with Toshiba A-BS6 at display power off). (translated by NEDO)

  17. Improved structural and electrical properties in native Sb2Te3/GexSb2Te3+x van der Waals superlattices due to intermixing mitigation

    Directory of Open Access Journals (Sweden)

    Stefano Cecchi

    2017-02-01

    Full Text Available Superlattices made of Sb2Te3/GeTe phase change materials have demonstrated outstanding performance with respect to GeSbTe alloys in memory applications. Recently, epitaxial Sb2Te3/GeTe superlattices were found to feature GexSb2Te3+x blocks as a result of intermixing between constituting layers. Here we present the epitaxy and characterization of Sb2Te3/GexSb2Te3+x van der Waals superlattices, where GexSb2Te3+x was intentionally fabricated. X-ray diffraction, Raman spectroscopy, scanning transmission electron microscopy, and lateral electrical transport data are reported. The intrinsic 2D nature of both sublayers is found to mitigate the intermixing in the structures, significantly improving the interface sharpness and ultimately the superlattice structural and electrical properties.

  18. Methodologic frontiers in environmental epidemiology.

    OpenAIRE

    Rothman, K J

    1993-01-01

    Environmental epidemiology comprises the epidemiologic study of those environmental factors that are outside the immediate control of the individual. Exposures of interest to environmental epidemiologists include air pollution, water pollution, occupational exposure to physical and chemical agents, as well as psychosocial elements of environmental concern. The main methodologic problem in environmental epidemiology is exposure assessment, a problem that extends through all of epidemiologic re...

  19. [Sb{sub 4}Au{sub 4}Sb{sub 4}]{sup 2−}: A designer all-metal aromatic sandwich

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Wen-Juan; You, Xue-Rui [Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China); Guo, Jin-Chang [Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000 (China); Li, Da-Zhi, E-mail: hj.zhai@sxu.edu.cn, E-mail: ldz005@126.com [Department of Chemical Engineering, Binzhou University, Binzhou 256603 (China); Wang, Ying-Jin [Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China); Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000 (China); Sun, Zhong-Ming [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhai, Hua-Jin, E-mail: hj.zhai@sxu.edu.cn, E-mail: ldz005@126.com [Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China); State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006 (China)

    2016-07-28

    We report on the computational design of an all-metal aromatic sandwich, [Sb{sub 4}Au{sub 4}Sb{sub 4}]{sup 2−}. The triple-layered, square-prismatic sandwich complex is the global minimum of the system from Coalescence Kick and Minima Hopping structural searches. Following a standard, qualitative chemical bonding analysis via canonical molecular orbitals, the sandwich complex can be formally described as [Sb{sub 4}]{sup +}[Au{sub 4}]{sup 4−}[Sb{sub 4}]{sup +}, showing ionic bonding characters with electron transfers in between the Sb{sub 4}/Au{sub 4}/Sb{sub 4} layers. For an in-depth understanding of the system, one needs to go beyond the above picture. Significant Sb → Au donation and Sb ← Au back-donation occur, redistributing electrons from the Sb{sub 4}/Au{sub 4}/Sb{sub 4} layers to the interlayer Sb–Au–Sb edges, which effectively lead to four Sb–Au–Sb three-center two-electron bonds. The complex is a system with 30 valence electrons, excluding the Sb 5s and Au 5d lone-pairs. The two [Sb{sub 4}]{sup +} ligands constitute an unusual three-fold (π and σ) aromatic system with all 22 electrons being delocalized. An energy gap of ∼1.6 eV is predicted for this all-metal sandwich. The complex is a rare example for rational design of cluster compounds and invites forth-coming synthetic efforts.

  20. Effects upon metabolic pathways and energy production by Sb(III and As(III/Sb(III-oxidase gene aioA in Agrobacterium tumefaciens GW4.

    Directory of Open Access Journals (Sweden)

    Jingxin Li

    Full Text Available Agrobacterium tumefaciens GW4 is a heterotrophic arsenite [As(III]/antimonite [Sb(III]-oxidizing strain. The As(III oxidase AioAB is responsible for As(III oxidation in the periplasm and it is also involved in Sb(III oxidation in Agrobacterium tumefaciens 5A. In addition, Sb(III oxidase AnoA and cellular H2O2 are also responsible for Sb(III oxidation in strain GW4. However, the deletion of aioA increased the Sb(III oxidation efficiency in strain GW4. In the present study, we found that the cell mobility to Sb(III, ATP and NADH contents and heat release were also increased by Sb(III and more significantly in the aioA mutant. Proteomics and transcriptional analyses showed that proteins/genes involved in Sb(III oxidation and resistance, stress responses, carbon metabolism, cell mobility, phosphonate and phosphinate metabolism, and amino acid and nucleotide metabolism were induced by Sb(III and were more significantly induced in the aioA mutant. The results suggested that Sb(III oxidation may produce energy. In addition, without periplasmic AioAB, more Sb(III would enter bacterial cells, however, the cytoplasmic AnoA and the oxidative stress response proteins were significantly up-regulated, which may contribute to the increased Sb(III oxidation efficiency. Moreover, the carbon metabolism was also activated to generate more energy against Sb(III stress. The generated energy may be used in Sb transportation, DNA repair, amino acid synthesis, and cell mobility, and may be released in the form of heat.

  1. Long-range order in InAsSb

    Science.gov (United States)

    Jen, H. R.; Ma, K. Y.; Stringfellow, G. B.

    1989-03-01

    Results are presented of transmission electron diffraction (TED) observations, demonstrating, for the first time, a CuPt-type ordering in InAs(1-x)Sb(x) alloys, over a wide range of x values (from x = 0.22 to 0.88). The InAsSb alloys were prepared by OMVPE on (001) oriented undoped InSb or InAs substrates. The ordering-induced spots on the TED patterns show the highest intensity for x of about 0.5 and the lowest intensity toward each binary end compound. Only two of the four variants are formed during growth. In some areas, the degree of order for these two variants, 1/2(-1 1 1) and 1/2(1 -1 1), is equal, and in other areas, one variant dominates.

  2. Old friends in a new light: 'SnSb' revisited

    International Nuclear Information System (INIS)

    Noren, Lasse; Withers, Ray L.; Schmid, Siegbert; Brink, Frank J.; Ting, Valeska

    2006-01-01

    The binary pnictide 'SnSb' has been re-investigated using a combination of X-ray, synchrotron and electron diffraction as well as electron microprobe analysis. Its structure was found to be incommensurately modulated with an underlying rhombohedral parent structure of space group symmetry R3-bar m (No. 166), unit cell parameters a h =b h =4.3251(4)A, c h =5.3376(6)A in the hexagonal setting. The incommensurate primary modulation wave vector q h =1.3109(9)c h * and the superspace group symmetry is R3-bar m (0, 0, ∼1.311) (No. 166.1). The refinement of the incommensurate structure indicates that the satellite reflections arise from displacive shifts of presumably essentially pure Sn and Sb layers along the hexagonal c-axis, with increasing distance between the Sn-layers and decreasing distance between the Sb layers

  3. Extremely large magnetoresistance and electronic structure of TmSb

    Science.gov (United States)

    Wang, Yi-Yan; Zhang, Hongyun; Lu, Xiao-Qin; Sun, Lin-Lin; Xu, Sheng; Lu, Zhong-Yi; Liu, Kai; Zhou, Shuyun; Xia, Tian-Long

    2018-02-01

    We report the magnetotransport properties and the electronic structure of TmSb. TmSb exhibits extremely large transverse magnetoresistance and Shubnikov-de Haas (SdH) oscillation at low temperature and high magnetic field. Interestingly, the split of Fermi surfaces induced by the nonsymmetric spin-orbit interaction has been observed from SdH oscillation. The analysis of the angle-dependent SdH oscillation illustrates the contribution of each Fermi surface to the conductivity. The electronic structure revealed by angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations demonstrates a gap at the X point and the absence of band inversion. Combined with the trivial Berry phase extracted from SdH oscillation and the nearly equal concentrations of electron and hole from Hall measurements, it is suggested that TmSb is a topologically trivial semimetal and the observed XMR originates from the electron-hole compensation and high mobility.

  4. Radiation-modified structure of Ge25Sb15S60 and Ge35Sb5S60 glasses

    International Nuclear Information System (INIS)

    Kavetskyy, T.; Shpotyuk, O.; Kaban, I.; Hoyer, W.

    2008-01-01

    Atomic structures of Ge 25 Sb 15 S 60 and Ge 35 Sb 5 S 60 glasses are investigated in the γ-irradiated and annealed after γ-irradiation states by means of high-energy synchrotron x-ray diffraction technique. The first sharp diffraction peak (FSDP) is detected at around 1.1 A -1 in the structure factors of both alloys studied. The FSDP position is found to be stable for radiation/annealing treatment of the samples, while the FSDP intensity shows some changes between γ-irradiated and annealed states. The peaks in the pair distribution functions observed between 2 and 4 A are related to the Ge-S, Ge-Sb, and Sb-Sb first neighbor correlations and Ge-Ge second neighbor correlations in the edge-shared GeS 4/2 tetrahedra, and S-S and/or Ge-Ge second neighbor correlations in the corner-shared GeS 4/2 tetrahedra. Three mechanisms of the radiation-/annealing-induced changes are discussed in the framework of coordination topological defect formation and bond-free solid angle concepts

  5. Investigation on the structural stability and electronic properties of InSb nanostructures – A DFT approach

    Directory of Open Access Journals (Sweden)

    V. Nagarajan

    2014-06-01

    Full Text Available The realistic InSb nanostructures namely InSb nanoring, InSb nanocube, InSb nanocube-18, InSb nanosheet, InSb nanocage and InSb nanocube-27 are simulated and optimized successfully using B3LYP/LanL2DZ basis set. The stability of InSb nanostructures is studied in terms of binding energy, vibrational studies and calculated energy. The electronic properties of InSb nanostructures are discussed using ionization potential, electron affinity and HOMO–LUMO gap. Point symmetry and dipole moment of InSb nanostructures are reported. Incorporation of impurity atom in InSb nanostructures is studied using embedding energy. The present study provides the information regarding the enhanced electronic properties of InSb nanostructure which finds its potential importance in microelectronics and optoelectronic devices.

  6. Amenorrhea after Endoscopic Third Ventriculostomy for a Failed Shunt in Spina Bifida: Case Report and Review of the Literature.

    Science.gov (United States)

    Giordano, Flavio; Spacca, Barbara; Danti, Alfredo; Taverna, Maria; Losi, Stefania; Stagi, Stefano; Genitori, Lorenzo

    2016-01-01

    Secondary endoscopic third ventriculostomy (ETV) for the management of shunt failure may be efficacious, though it may be followed by more frequent complications (including endocrinological impairment, e.g., amenorrhea) compared to primary ETV. These complications are usually underreported in the literature. We report a case of secondary amenorrhea after ETV for the management of shunt failure in a young woman with hydrocephalus associated with myelomeningocele. A 25-year-old woman affected by hydrocephalus and myelomeningocele was admitted for secondary ETV for the management of shunt failure. The endoscopic procedure was preferred over shunt revision based on good results of secondary ETV, especially in patients with hydrocephalus associated with Chiari II malformation and spina bifida. Despite the surgery being uneventful, the patient had early (postoperative seizure) and late (secondary amenorrhea) complications. In the early postoperative period, she received external ventricular drainage followed by VP shunt reimplantation 2 weeks later. There was no neurological morbidity, but 1 month after the ETV she reported secondary amenorrhea and weight gain. Laboratory investigations ruled out hyperprolactinemia, which had been treated with cabergoline administration with no efficacy since the patient was still without regular periods 1 year later. ETV may be followed by endocrinological complications like amenorrhea that are rarely reported. © 2015 S. Karger AG, Basel.

  7. Generation of Induced Pluripotent Stem Cells and Neural Stem/Progenitor Cells from Newborns with Spina Bifida Aperta.

    Science.gov (United States)

    Bamba, Yohei; Nonaka, Masahiro; Sasaki, Natsu; Shofuda, Tomoko; Kanematsu, Daisuke; Suemizu, Hiroshi; Higuchi, Yuichiro; Pooh, Ritsuko K; Kanemura, Yonehiro; Okano, Hideyuki; Yamasaki, Mami

    2017-12-01

    We established induced pluripotent stem cells (iPSCs) and neural stem/progenitor cells (NSPCs) from three newborns with spina bifida aperta (SBa) using clinically practical methods. We aimed to develop stem cell lines derived from newborns with SBa for future therapeutic use. SBa is a common congenital spinal cord abnormality that causes defects in neurological and urological functions. Stem cell transplantation therapies are predicted to provide beneficial effects for patients with SBa. However, the availability of appropriate cell sources is inadequate for clinical use because of their limited accessibility and expandability, as well as ethical issues. Fibroblast cultures were established from small fragments of skin obtained from newborns with SBa during SBa repair surgery. The cultured cells were transfected with episomal plasmid vectors encoding reprogramming factors necessary for generating iPSCs. These cells were then differentiated into NSPCs by chemical compound treatment, and NSPCs were expanded using neurosphere technology. We successfully generated iPSC lines from the neonatal dermal fibroblasts of three newborns with SBa. We confirmed that these lines exhibited the characteristics of human pluripotent stem cells. We successfully generated NSPCs from all SBa newborn-derived iPSCs with a combination of neural induction and neurosphere technology. We successfully generated iPSCs and iPSC-NSPCs from surgical samples obtained from newborns with SBa with the goal of future clinical use in patients with SBa.

  8. The relationship between intellectual skills and the computerised axial tomograms of children with spina bifida and hydrocephalus

    International Nuclear Information System (INIS)

    Lonton, A.P.

    1979-01-01

    Cranial CT-scans of 467 patients were graded in degrees of severity of hydrocephalus. The patients were aged from 2-22 years and had spina bifida and/or hydrocephalus or related disorders. Even large increases in the degree of hydrocephalus were found to have an insignificant effect upon verbal IQ, but there was a small but statistically significant effect upon performance scale IQ on the WISC. The abilities most affected were those involving the use of motor and perceptuo-motor skills. Assymmetrical or other abnormal scans were found to be associated with lower IQ. Children with valves were only found to be substantially inferior in skills to those without valves when their ventricles were either very large, or abnormally small. The highest proportion of children with valves was found in the group with the smallest ventricles, followed by the group with the largest ventricles. Very small ventricles are known to be associated with an increased rate of valve complications, and this paper shows that there are psychological disadvantages also. (orig.) [de

  9. Experimental determination of the energy levels of the antimony atom (Sb II), ions of the antimony (Sb II, Sb III), mercury (Hg IV) and cesium (Cs X)

    International Nuclear Information System (INIS)

    Arcimowicz, B.

    1993-01-01

    The thesis concerns establishing the energy scheme of the electronic levels, obtained from the analysis of the investigated spectra of antimony atom and ions (Sb I, Sb II, Sb III) and higher ionized mercury (Hg IV) and cesium (Cs X) atoms. The experimental studies were performed with optical spectroscopy methods. The spectra of the elements under study obtained in the spectral range from visible (680 nm) to vacuum UV (40 nm) were analysed. The classification and spectroscopic designation of the experimentally established 169 energy levels were obtained on the basis of the performed calculations and the fine structure analysis. The following configurations were considered: 5s 2 5p 2 ns, 5s 2 5p 2 n'd, 5s5p 4 of the antimony atom, 5s 2 5pns, 5s 2 5pn'd, 5s5p 3 of the ion Sb II, 5s 2 ns, 5s 2 n'd, 5s5p 2 of the on Sb III, 5d 8 6p of the ion Hg IV 4d 9 5s and 4d 9 5p Cs X. A reclassification was performed and some changes were introduced to the existing energy level scheme of the antimony atom, with the use of the information obtained from the absorption spectrum taken in the VUV region by the ''flash pyrolysis'' technique. The measurements of the hyperfine splittings in 19 spectral lines belonging to the antimony atom and ions additionally confirmed the assumed classification of the levels involved in these lines. The energy level scheme, obtained for Sb III, was compared to the other ones in the isoelectronic sequence starting with In I. On the basis of the analysis of the Hg IV spectrum it was proved that ground configuration of the three times ionized mercury atom is 5d 9 not 5d 8 6s as assumed until now. The fine structure, established from the analysis of the spectra of the elements under study was examined in multiconfiguration approximation. As a result of the performed calculations the fine structure parameters and wavefunctions were determined for the levels whose energy values were experimentally established in the thesis. (author). 140 refs, 22 figs, 17

  10. Development in Zn4Sb-based thermoelectric materials

    DEFF Research Database (Denmark)

    Yin, Hao

    or thermopower,  the electrical conductivity, the thermal conductivity and T the absolute temperature. The best thermoelectrics are heavily doped semiconductors with high thermoelectric power factors and low thermal conductivities, known as “Phonon Glasses Electrical Crystals”. Zn4Sb3 is one such material......-section. The following part reports the effect of nano-particles on the thermoelectric properties and thermal stability of Zn4Sb3. Though TiO2 nano particles have remarkably enhanced the stability, the thermoelectric performance of all the nano-composites deteriorates. Optimization of the content of the nano...

  11. Cathodoluminescence study of ytterbium doped GaSb

    International Nuclear Information System (INIS)

    Hidalgo, P.; Mendez, B.; Ruiz, C.; Bermudez, V.; Piqueras, J.; Dieguez, E.

    2005-01-01

    Yb-doped GaSb ingots have been grown by the Bridgman method. The defect structure and compositional homogeneity of the crystals have been investigated by cathodoluminescence and X-ray microanalysis in the scanning electron microscope. The nature of the point defects has been found to depend on the position along the growth axis. Doping with Yb has been found to reduce the luminescence intensity of GaSb and no infrared emission related to intra-ionic transitions of the Yb 3+ ions has been detected

  12. Magnetic Phase Transitions of CeSb. I

    DEFF Research Database (Denmark)

    Fischer, Pernille Hertz; Lebech, Bente; Meier, G.

    1978-01-01

    The magnetic ordering of the anomalous antiferromagnet CeSb, which has a NaCl crystal structure, was determined in zero applied magnetic field by means of neutron diffraction investigations of single crystals and powder. Below the Neel temperature TN of (16.1+or-0.1)K, there exist six partially...... a first-order phase transition at TN. At approximately TN/2 there is a first-order phase transition to a FCC type IA low-temperature configuration. The unusual magnetic properties of CeSb, which result from anisotropic exchange and crystalline electric field effects, resemble those of certain actinide Na...

  13. Decays of 116Sb isomers to levels in 116Sn

    International Nuclear Information System (INIS)

    Gacsi, Z.; Raman, S.

    1994-01-01

    The excited states of 116 Sn were studied by means of the decays of the 15.8-min, 3 + 116 Sb ground state, and the 60.3-min, 8 - 116 Sb isomer. Over 50 γ rays were observed; these were incorporated into a level scheme consisting of 32 excited states. Except for one new level proposed at 3.986 MeV, the current study fully supports an exhaustive study of levels in 116 Sn reported earlier. The previous study was an attempt to develop a nearly ''complete'' level scheme of 116 Sn up to an excitation energy of 4.3 MeV

  14. Lead activity in Pb-Sb-Bi alloys

    Directory of Open Access Journals (Sweden)

    A. S. Kholkina

    2014-11-01

    Full Text Available The present work is devoted to the study of lead thermodynamic activity in the Pb-Sb-Bi alloys. The method for EMF measurements of the concentration cell: (–Pb|KCl-PbCl2¦¦KCl-PbCl2|Pb-(Sb-Bi(+ was used. The obtained concentration dependences of the galvanic cell EMF are described by linear equations. The lead activity in the ternary liquid-metal alloy demonstrates insignificant negative deviations from the behavior of ideal solutions.

  15. Optical and structural characterization of GaSb and Te-doped GaSb single crystals

    International Nuclear Information System (INIS)

    Tirado-Mejia, L.; Villada, J.A.; Rios, M. de los; Penafiel, J.A.; Fonthal, G.; Espinosa-Arbelaez, D.G.; Ariza-Calderon, H.; Rodriguez-Garcia, M.E.

    2008-01-01

    Optical and structural properties of GaSb and Te-doped GaSb single crystals are reported herein. Utilizing the photoreflectance technique, the band gap energy for doped samples was obtained at 0.814 eV. Photoluminescence (PL) spectra showed a peak at 0.748 eV that according to this research, belongs to electronic states of pure GaSb and not to the longitudinal optical (LO) phonon replica as has been reported by other authors. Analysis of the full width at half maximum (FWHM) values of X-ray diffraction, as well as micro-Raman peaks showed that the inclusion of Te decreases the crystalline quality

  16. Fatores genéticos e ambientais associados a espinha bífida Genetic and ambient factors and profile of the newborns with spina bifida

    Directory of Open Access Journals (Sweden)

    Cristiane de Jesus da Cunha

    2005-05-01

    Full Text Available OBJETIVOS: analisar a freqüência e os fatores associados à ocorrência da espinha bífida. MÉTODOS: os dados foram obtidos por meio de entrevista de 47 casos e 47 controles, nascidos nas cinco maternidades da cidade de Pelotas, durante o período de 1 de Janeiro de 1990 a 31 de Dezembro de 2003. É estudo com delineamento de caso-controle, de base populacional que abrangeu todos os nascimentos hospitalares. O controle foi o neonato normal que nasceu após cada caso com malformação. Todos os dados foram obtidos mediante questionário-modelo. A análise do planejamento de análise de dados incluiu o uso do teste t de Student, chi² e odds ratio. RESULTADOS: ocorreram aproximadamente 77.000 nascimentos nesse período. Desses, 1.043 (1,3% apresentaram algum tipo de malformação congênita. Dentre essas, 47 de 162 anomalias do fechamento do tubo neural foram diagnosticadas como espinha bífida. Foram encontradas diferenças significativas quanto ao número de natimortos prévios, bem como proporção superior de casos de espinha bífida em recém-nascidos do sexo feminino. Neste estudo, muitos fatores como o uso de medicamentos; doenças agudas; afecções crônicas; número de gestações; idade, escolaridade e ocupação dos pais, entre outros, não mostraram associação com o nascimento de recém-nascido com espinha bífida. CONCLUSÕES: a espinha bífida deve ser considerada como importante fator de risco para a morbidade perinatal, e sua ocorrência está associada a um histórico gestacional de natimortos prévios.PURPOSES: to analyze the frequency, associated risk factors for the occurrence of spina bifida and differences between the newborns carrying this malformation and the newborns' morbidities. METHODS: data were obtained through interview of 47 cases and 47 controls, born in the five maternities of the city of Pelotas, during the period from January 1, 1990 to December 31, 2003. This is a population-based case-control study

  17. Uncooled High-Performance InAsSb Focal Plane Arrays, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SVT Associates proposes an innovative digital alloy technique to extend the cutoff wavelength of InAsSb beyond 5 um, a wider band gap InAlAsSb layer inserted into...

  18. AEMnSb2 (AE=Sr, Ba): a new class of Dirac materials

    International Nuclear Information System (INIS)

    Farhan, M Arshad; Lee, Geunsik; Shim, Ji Hoon

    2014-01-01

    The Dirac fermions of Sb square net in AEMnSb 2 (AE=Sr, Ba) are investigated by using first-principles calculation. BaMnSb 2 contains Sb square net layers with a coincident stacking of Ba atoms, exhibiting Dirac fermion behavior. On the other hand, SrMnSb 2 has a staggered stacking of Sr atoms with distorted zig-zag chains of Sb atoms. Application of hydrostatic pressure on the latter induces a structural change from a staggered to a coincident arrangement of AE ions accompanying a transition from insulator to a metal containing Dirac fermions. The structural investigations show that the stacking type of cation and orthorhombic distortion of Sb layers are the main factors to decide the crystal symmetry of the material. We propose that the Dirac fermions can be obtained by controlling the size of cation and the volume of AEMnSb 2 compounds. (fast track communication)

  19. Raman spectra of the system TeCl4-SbCl5

    International Nuclear Information System (INIS)

    Brockner, W.; Demiray, A.F.

    1980-01-01

    Raman spectra of the solid and molten TeCl 4 . SbCl 5 addition compound and of some TeCl 4 -SbCl 5 mixtures have been recorded. Two modifications of the crystalline TeCl 4 -SbCl 5 compound have been found. The structure of the melt can be described by the equilibrium TeCl 3 + + SbCl 6 - reversible TeCl 4 + SbCl 5 lying on the left side. Mixtures with other stoichiometry contain the 1:1 adduct only and excess TeCl 4 or SbCl 5 , respectively. Such melts are built up by the ionic species TeCl 3 + and SbCl 6 - also and TeCl 4 or SbCl 5 according to stoichiometry. (author)

  20. Fate and chemical speciation of antimony (Sb) during uptake, translocation and storage by rye grass using XANES spectroscopy.

    Science.gov (United States)

    Ji, Ying; Sarret, Géraldine; Schulin, Rainer; Tandy, Susan

    2017-12-01

    Antimony (Sb) is a contaminant of increased prevalence in the environment, but there is little knowledge about the mechanisms of its uptake and translocation within plants. Here, we applied for the synchrotron based X-ray absorption near-edge structure (XANES) spectroscopy to analyze the speciation of Sb in roots and shoots of rye grass (Lolium perenne L. Calibra). Seedlings were grown in nutrient solutions to which either antimonite (Sb(III)), antimonate (Sb(V)) or trimethyl-Sb(V) (TMSb) were added. While exposure to Sb(III) led to around 100 times higher Sb accumulation in the roots than the other two treatments, there was no difference in total Sb in the shoots. Antimony taken up in the Sb(III) treatment was mainly found as Sb-thiol complexes (roots: >76% and shoots: 60%), suggesting detoxification reactions with compounds such as glutathione and phytochelatins. No reduction of accumulated Sb(V) was found in the roots, but half of the translocated Sb was reduced to Sb(III) in the Sb(V) treatment. Antimony accumulated in the TMSb treatment remained in the methylated form in the roots. By synchrotron based XANES spectroscopy, we were able to distinguish the major Sb compounds in plant tissue under different Sb treatments. The results help to understand the translocation and transformation of different Sb species in plants after uptake and provide information for risk assessment of plant growth in Sb contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of FeSb6 octahedral deformations on the electronic structure of LaFe4Sb12

    KAUST Repository

    Pulikkotil, Jiji Thomas Joseph

    2011-09-01

    First-principles density functional based electronic structure calculations are performed in order to clarify the influence of FeSb6 octahedral deformations on the structural and electronic structure properties of LaFe 4Sb12. Our results show that octahedral tiltings correlate with the band dispersions and, consequently, the band masses. While total energy variation points at an enhanced role of lattice anharmonicity, flat bands emerge from a redistribution of the electronic states. © 2011 Elsevier B.V. All rights reserved.

  2. A girl with spina bifida, an extra leg, and ectopic intestinal loops--a "foetus in foetu" or a whim of the neural crest?

    Science.gov (United States)

    Lende, G; Wendemu, W; Mørk, S; Wester, K

    2007-10-01

    This article describes a girl with an extra leg attached to her lower back, combined with a spina bifida and a myelomeningocele. Despite lacking sensory or motor functions, the leg grew proportionately with the rest of the body. The bony structures were almost normal. A cross section showed fat tissue with some centrally situated blood vessels, nerve bundles, and muscular fragments. Proximally, an isolated colon loop was found. The extra leg and intestine respected the dorsal fascia, without connection with the peritoneal or retroperitoneal compartments. The finding is discussed with reference to existing hypotheses for limb formation.

  3. Against Popperized epidemiology.

    Science.gov (United States)

    Jacobsen, M

    1976-03-01

    The recommendation of Popper's philosophy of science should be adopted by epidemiologists is disputed. Reference is made to other authors who have shown that the most constructive elements in Popper's ideas have been advocated by earlier philosophers and have been used in epidemiology without abandoning inductive reasoning. It is argued that Popper's denigration of inductive methods is particularly harmful to epidemiology. Inductive reasoning and statistical inference play a key role in the science; it is suggested that unfamiliarity with these ideas contributes to widespread misunderstanding of the function of epidemiology. Attention is drawn to a common fallacy involving correlations between three random variables. The prevalence of the fallacy may be related to confusion between deductive and inductive logic.

  4. Ophthalmic epidemiology in Europe

    DEFF Research Database (Denmark)

    Delcourt, Cécile; Korobelnik, Jean-François; Buitendijk, Gabriëlle H S

    2016-01-01

    The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 population-based studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170,000 Euro......The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 population-based studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170......,000 European participants. The aim of the consortium is to promote and sustain collaboration and sharing of data and knowledge in the field of ophthalmic epidemiology in Europe, with particular focus on the harmonization of methods for future research, estimation and projection of frequency and impact...

  5. Single step hydrothermal based synthesis of M(II)Sb2O6 (M = Cd ...

    Indian Academy of Sciences (India)

    characterized by powder X-ray diffraction, scanning electron microscopy, energy dispersive .... SEM images and EDAX analysis of (a) and (b) CdSb2O6 and (c) and (d) ZnSb2O6. ... The parent compound, ilmenite (NaSbO3) could degrade MB.

  6. Stress-Induced Crystallization of Ge-Doped Sb Phase-Change Thin Films

    NARCIS (Netherlands)

    Eising, Gert; Pauza, Andrew; Kooi, Bart J.

    The large effects of moderate stresses on the crystal growth rate in Ge-doped Sb phase-change thin films are demonstrated using direct optical imaging. For Ge6Sb94 and Ge7Sb93 phase-change films, a large increase in crystallization temperature is found when using a polycarbonate substrate instead of

  7. Assessing Intellectual Functioning in Young Adolescents: How Do the WISC-IV and SB5 Compare?

    Science.gov (United States)

    Wilson, Kimberley; Gilmore, Linda

    2012-01-01

    The Wechsler Intelligence Scale for Children--Fourth Edition (WISC-IV) and the Stanford-Binet--Fifth Edition (SB5) are two of the most commonly used intelligence tests for children and adolescents. No comparative studies of the WISC-IV and SB5 have yet been published. In the current study the WISC-IV and SB5 were administered in counterbalanced…

  8. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    International Nuclear Information System (INIS)

    Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam; Singh, Chandan K.; Kabir, Mukul; Thakur, Gohil S.; Haque, Zeba; Gupta, L. C.; Ganguli, Ashok K.

    2016-01-01

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  9. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    Energy Technology Data Exchange (ETDEWEB)

    Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO 140306 (India); Singh, Chandan K.; Kabir, Mukul [Department of Physics, Indian Institute of Science Education and Research, Pune 411008 (India); Thakur, Gohil S.; Haque, Zeba; Gupta, L. C. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Institute of Nano Science & Technology, Mohali 160064 (India)

    2016-06-13

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  10. Optical characteristics of crystalline antimony sulphide (Sb 2 S 3 ...

    African Journals Online (AJOL)

    This paper presents the important optical characteristics of crystalline Sb2S3 film deposited on glass substrate using solution growth technique at 300k. These characteristics were analyzed using PYEUNICAM SP8-100 spectrophotometer in the range of UV-VIS-NIR while the morphology and the structural composition were ...

  11. Experimental Study of the Sb-Sn-Zn Alloy System

    Czech Academy of Sciences Publication Activity Database

    Zobač, O.; Sopoušek, J.; Buršík, Jiří; Zemanová, Adéla; Roupcová, Pavla

    2014-01-01

    Roč. 45, č. 3 (2014), s. 1181-1188 ISSN 1073-5623 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Sb-Sn-Zn system * thermal analysis * CALPHAD method Subject RIV: BJ - Thermodynamics Impact factor: 1.730, year: 2014

  12. Resonant photoemission study of CeRu4Sb12

    International Nuclear Information System (INIS)

    Ishii, Hiroyoshi; Miyahara, Tsuneaki; Takayama, Yasuhiro; Shiozawa, Hidetsugu; Obu, Kenji; Matsuda, Tatsuma D.; Aoki, Yuji; Sugawara, Hitoshi; Sato, Hideyuki

    2005-01-01

    We have measured the Ce 4d-4f and Ce 3d-4f resonant photoemission spectra of CeRu 4 Sb 12 . The Ce 4f spectra show the spectral features corresponding to a weakly hybridized system. The number of 4f electrons is estimated to be ∼1.0

  13. Draft Genome Sequence of Corynebacterium kefirresidentii SB, Isolated from Kefir.

    Science.gov (United States)

    Blasche, Sonja; Kim, Yongkyu; Patil, Kiran R

    2017-09-14

    The genus Corynebacterium includes Gram-positive species with a high G+C content. We report here a novel species, Corynebacterium kefirresidentii SB, isolated from kefir grains collected in Germany. Its draft genome sequence was remarkably dissimilar (average nucleotide identity, 76.54%) to those of other Corynebacterium spp., confirming that this is a unique novel species. Copyright © 2017 Blasche et al.

  14. Two-band superlinear electroluminescence in GaSb based nanoheterostructures with AlSb/InAs.sub.1-x./sub.Sb.sub.x./sub./AlSb deep quantum well

    Czech Academy of Sciences Publication Activity Database

    Mikhailova, M. P.; Ivanov, E.V.; Danilov, L.V.; Petukhov, A.A.; Kalinina, K.V.; Slobozhanyuk, S.I.; Zegrya, G.G.; Stoyanov, N. D.; Yakovlev, Yu. P.; Hospodková, Alice; Pangrác, Jiří; Oswald, Jiří; Zíková, Markéta; Hulicius, Eduard

    2014-01-01

    Roč. 115, č. 22 (2014), "223102-1"-"223102-5" ISSN 0021-8979 R&D Projects: GA ČR GA13-15286S Institutional support: RVO:68378271 Keywords : MOVPE * GaSb * InAs * electroluminescence * quantum well Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2014

  15. Commensurate-commensurate magnetic phase transitions in CeSb

    DEFF Research Database (Denmark)

    Lebech, Bente; Broholm, C.; Clausen, K.

    1986-01-01

    The q=2/3 to q=4/7 commensurate-commensurate phase transition in CeSb has been studied by neutron diffraction. On cooling the commensurate wave vector q changes abruptly from 2/3 to a higher-order commensurate value (≈14/23) at T1

  16. Triplet superconductivity in PrOs4Sb12

    International Nuclear Information System (INIS)

    Maki, K.; Won, H.; Parker, David; Haas, Stephan; Izawa, K.; Matsuda, Y.

    2005-01-01

    Here we propose spin triplet superconductors for the A- and B-phase in PrOs 4 Sb 12 . The present model describes consistently the thermal conductivity κ zz data obtained by Izawa et al. for T>=150mK

  17. Programming biological models in Python using PySB.

    Science.gov (United States)

    Lopez, Carlos F; Muhlich, Jeremy L; Bachman, John A; Sorger, Peter K

    2013-01-01

    Mathematical equations are fundamental to modeling biological networks, but as networks get large and revisions frequent, it becomes difficult to manage equations directly or to combine previously developed models. Multiple simultaneous efforts to create graphical standards, rule-based languages, and integrated software workbenches aim to simplify biological modeling but none fully meets the need for transparent, extensible, and reusable models. In this paper we describe PySB, an approach in which models are not only created using programs, they are programs. PySB draws on programmatic modeling concepts from little b and ProMot, the rule-based languages BioNetGen and Kappa and the growing library of Python numerical tools. Central to PySB is a library of macros encoding familiar biochemical actions such as binding, catalysis, and polymerization, making it possible to use a high-level, action-oriented vocabulary to construct detailed models. As Python programs, PySB models leverage tools and practices from the open-source software community, substantially advancing our ability to distribute and manage the work of testing biochemical hypotheses. We illustrate these ideas using new and previously published models of apoptosis.

  18. Nuclear accidents and epidemiology

    International Nuclear Information System (INIS)

    1987-01-01

    A consultation on epidemiology related to the Chernobyl accident was held in Copenhagen in May 1987 as a basis for concerted action. This was followed by a joint IAEA/WHO workshop in Vienna, which reviewed appropriate methodologies for possible long-term effects of radiation following nuclear accidents. The reports of these two meetings are included in this volume, and cover the subjects: 1) Epidemiology related to the Chernobyl nuclear accident. 2) Appropriate methodologies for studying possible long-term effects of radiation on individuals exposed in a nuclear accident. Figs and tabs

  19. Advances in radiation epidemiology

    International Nuclear Information System (INIS)

    Boice, J.

    1997-01-01

    The 1994 UNSCEAR report provides an informative review of radiation epidemiology. During the past 2 years there have been several major advances in our understanding of radiation effects based on new studies of atomic bomb survivors in Japan, of patients given diagnostic and therapeutic radiation (including iodine-131), of workers occupationally exposed, and of general populations exposed to residential radon. Laboratory approaches are also being incorporated into epidemiological investigations to learn more about the biological mechanism by which radiation causes cancer in man. (author)

  20. Effect of Sb content on the thermoelectric properties of annealed CoSb{sub 3} thin films deposited via RF co-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Aziz, E-mail: aziz_ahmed@ust.ac.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Han, Seungwoo, E-mail: swhan@kimm.re.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

    2017-06-30

    Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb{sub 3} phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb{sub 2} phase possess the largest power factor. - Abstract: A series of CoSb{sub 3} thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb{sub 3} thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb{sub 2} and CoSb{sub 3} components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb{sub 3} thin films. The CoSb{sub 2} phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb{sub 3} thin films. We report maximum power factor of 7.92 mW/m K{sup 2} for the CoSb{sub 2}-containing mixed phase thin film and 1

  1. Effect of Sb content on the thermoelectric properties of annealed CoSb_3 thin films deposited via RF co-sputtering

    International Nuclear Information System (INIS)

    Ahmed, Aziz; Han, Seungwoo

    2017-01-01

    Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb_3 phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb_2 phase possess the largest power factor. - Abstract: A series of CoSb_3 thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb_3 thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb_2 and CoSb_3 components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb_3 thin films. The CoSb_2 phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb_3 thin films. We report maximum power factor of 7.92 mW/m K"2 for the CoSb_2-containing mixed phase thin film and 1.26 mW/m K"2 for the stoichiometric CoSb_3 thin film.

  2. Thermoelectric and mechanical properties of spark plasma sintered Cu3SbSe3 and Cu3SbSe4: Promising thermoelectric materials

    Science.gov (United States)

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

    2014-12-01

    We report the synthesis of thermoelectric compounds, Cu3SbSe3 and Cu3SbSe4, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu3SbSe4 exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu3SbSe3, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu3SbSe4 was found to be ˜1.2 as compared to 0.2 V-1 for Cu3SbSe3 at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

  3. Sb(III)-Imprinted Organic-Inorganic Hybrid Sorbent Prepared by Hydrothermal-Assisted Surface Imprinting Technique for Selective Adsorption of Sb(III)

    Science.gov (United States)

    Zhang, Dan; Zhao, Yue; Xu, Hong-Bo

    2018-03-01

    Sb(III)-imprinted organic-inorganic hybrid sorbent was prepared by hydrothermal-assisted surface imprinting technique and was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy coupled to an energy dispersive spectrometer and N2 adsorption/desorption isotherms. Hydrothermal-assisted process can improve the selectivity of the Sb(III)-imprinted hybrid sorbent for Sb(III) due to stable control of temperature and pressure. The Sb(III)-imprinted hybrid sorbent IIS indicated higher selectivity for Sb(III), had high static adsorption capacity of 37.3 mg g-1 for Sb(III), displayed stable adsorption capacity in pH range from 4 to 8, reached an rapid adsorption equilibrium within 30 min. According to the correlation coefficient ( r 2 > 0.99), the experimental data fitted better the pseudo-second-order kinetic model and Langmuir equilibrium isotherm.

  4. A 121Sb Moessbauer Study of the Chemical State of Antimony in V-Sb-O Mixed-Oxide Catalysts for the Ammoxidation of Propane

    International Nuclear Information System (INIS)

    Stievano, L.; Wagner, F. E.; Zanthoff, H. W.; Calogero, S.

    2002-01-01

    The structural changes of two representative samples of a group of V-Sb-oxide catalysts, a vanadium-rich and an antimony-rich specimen, are investigated by 121 Sb Moessbauer spectroscopy after treatment under propene or hydrogen at 673 K. The as-prepared catalysts contain both Sb(V) and Sb(III) as crystalline and microcrystalline α-Sb 2 O 4 and VSbO 4 , as well as an additional amorphous V 5+ oxide phase. The oxidation state of antimony does not change upon exposure to propene, whereas a partial reduction can be obtained by a more intense reduction under hydrogen. The Moessbauer results indicate that the antimony in VSbO 4 can be reduced more easily than that in α-Sb 2 O 4 , which appears to be more stable. These results are discussed in view of the observed depletion of vanadium at the surface of the catalyst particles under reaction conditions.

  5. Interface between Sn-Sb-Cu solder and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sebo, P., E-mail: Pavel.Sebo@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Svec, P. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janickovic, D.; Illekova, E. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine)

    2011-07-15

    Highlights: {yields} New lead-free solder materials based on Sn-Sb-Cu were designed and prepared. {yields} Melting and solidification temperatures of the solders have been determined. {yields} Cu-substrate/solder interaction has been analyzed and quantified. {yields} Phases formed at the solder-substrate interface have been identified. {yields} Composition and soldering atmospheres were correlated with joint strength. - Abstract: Influence of antimony and copper in Sn-Sb-Cu solder on the melting and solidification temperatures and on the microstructure of the interface between the solder and copper substrate after wetting the substrate at 623 K for 1800 s were studied. Microstructure of the interface between the solder and copper substrates in Cu-solder-Cu joints prepared at the same temperature for 1800 s was observed and shear strength of the joints was measured. Influence of the atmosphere - air with the flux and deoxidising N{sub 2} + 10H{sub 2} gas - was taken into account. Thermal stability and microstructure were studied by differential scanning calorimetry (DSC), light microscopy, scanning electron microscopy (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). Melting and solidification temperatures of the solders were determined. An interfacial transition zone was formed by diffusion reaction between solid copper and liquid solder. At the interface Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} phases arise. Cu{sub 3}Sn is adjacent to the Cu substrate and its thickness decreases with increasing the amount of copper in solder. Scallop Cu{sub 6}Sn{sub 5} phase is formed also inside the solder drop. The solid solution Sn(Sb) and SbSn phase compose the interior of the solder drop. Shear strength of the joints measured by push-off method decreases with increasing Sb concentration. Copper in the solder shows even bigger negative effect on the strength.

  6. Complexation of HSA with different forms of antimony (Sb): An application of fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Song, Wenjuan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong

    2013-01-01

    Antimony (Sb) pollution has been of a great environmental concern in some areas in China. Sb enters human body via drinking water, inhalation and food chain, unavoidably interacts with human serum albumin (HSA) in blood plasma, and consequently does harm to human health. The harmful effects of Sb on human health depend on the Sb species and their binding ability to HSA. In the present study, binding of three forms of Sb with HSA was investigated by excitation-emission matrix (EEM) spectroscopy. All of antimony potassium tartrate, antimony trichloride and potassium pyroantimonate quenched fluorescence of HSA. Values of conditional stability constant K a (×10 5 /M) for Sb and HSA systems were 8.13–9.12 for antimony potassium tartrate, 2.51–4.27 for antimony trichloride and 3.63–9.77 for potassium pyroantimonate. The binding constant K b (×10 4 /M) values of HSA with antimony potassium tartrate, antimony trichloride and potassium pyroantimonate were 0.02–0.07, 3.55–5.01, and 0.07–1.08, respectively. There was one independent class of binding site for antimony trichloride towards HSA. There was more than one Sb binding site and negative cooperativity between multiple binding sites for potassium pyroantimonate and antimony potassium tartrate towards HSA. The binding ability of HSA to complex Sb followed the order: antimony trichloride>potassium pyroantimonate>antimony potassium tartrate. -- Highlights: ► The first study reporting interaction of Sb with HSA. ► Sb can effectively quench the fluorescence of HSA. ► The binding ability of HSA to Sb was dependent on the form of Sb. ► Binding differences indicate differences in toxicity of various forms Sb to human. ► HAS-Sb binding parameters are important for understanding toxicity of Sb

  7. Complexation of HSA with different forms of antimony (Sb): An application of fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Wenjuan [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Zhang, Daoyong [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Pan, Xiangliang, E-mail: xlpan@ms.xjb.ac.cn [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Lee, Duu-Jong [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China)

    2013-04-15

    Antimony (Sb) pollution has been of a great environmental concern in some areas in China. Sb enters human body via drinking water, inhalation and food chain, unavoidably interacts with human serum albumin (HSA) in blood plasma, and consequently does harm to human health. The harmful effects of Sb on human health depend on the Sb species and their binding ability to HSA. In the present study, binding of three forms of Sb with HSA was investigated by excitation-emission matrix (EEM) spectroscopy. All of antimony potassium tartrate, antimony trichloride and potassium pyroantimonate quenched fluorescence of HSA. Values of conditional stability constant K{sub a} (×10{sup 5}/M) for Sb and HSA systems were 8.13–9.12 for antimony potassium tartrate, 2.51–4.27 for antimony trichloride and 3.63–9.77 for potassium pyroantimonate. The binding constant K{sub b} (×10{sup 4}/M) values of HSA with antimony potassium tartrate, antimony trichloride and potassium pyroantimonate were 0.02–0.07, 3.55–5.01, and 0.07–1.08, respectively. There was one independent class of binding site for antimony trichloride towards HSA. There was more than one Sb binding site and negative cooperativity between multiple binding sites for potassium pyroantimonate and antimony potassium tartrate towards HSA. The binding ability of HSA to complex Sb followed the order: antimony trichloride>potassium pyroantimonate>antimony potassium tartrate. -- Highlights: ► The first study reporting interaction of Sb with HSA. ► Sb can effectively quench the fluorescence of HSA. ► The binding ability of HSA to Sb was dependent on the form of Sb. ► Binding differences indicate differences in toxicity of various forms Sb to human. ► HAS-Sb binding parameters are important for understanding toxicity of Sb.

  8. Oral administration of the 5-HT6 receptor antagonists SB-357134 and SB-399885 improves memory formation in an autoshaping learning task.

    Science.gov (United States)

    Perez-García, Georgina; Meneses, Alfredo

    2005-07-01

    In this work we aimed to re-examine the 5-HT6 receptor role, by testing the selective antagonists SB-357134 (1-30 mg/kg p.o.) and SB-399885 (1-30 mg/kg p.o.) during memory consolidation of conditioned responses (CR%), in an autoshaping Pavlovian/instrumental learning task. Bioavailability, half-life and minimum effective dose to induce inappetence for SB-357134 were 65%, 3.4 h, and 30 mg/kg p.o., and for SB-399885 were 52%, 2.2 h, and 50 mg/kg p.o., respectively. Oral acute and chronic administration of either SB-357134 or SB-399885 improved memory consolidation compared to control groups. Acute administration of SB-357134, at 1, 3, 10 and 30 mg/kg, produced a CR% inverted-U curve, eliciting the latter dose a 7-fold increase relative to saline group. Acute injection of SB-399885 produced significant CR% increments, being 1 mg/kg the most effective dose. Repeated administration (7 days) of either SB-357134 (10 mg/kg) or SB-399885 (1 mg/kg) elicited the most significant CR% increments. Moreover, modeling the potential therapeutic benefits of 5-HT6 receptor blockade, acute or repeated administration of SB-399885, at 10 mg/kg reversed memory deficits produced by scopolamine or dizocilpine, and SB-357134 (3 and 10 mg/kg) prevented amnesia and even improved performance. These data support the notion that endogenously 5-HT acting, via 5-HT6 receptor, improves memory consolidation.

  9. Effect of Sb Segregation on Conductance and Catalytic Activity at Pt/Sb-Doped SnO2 Interface: A Synergetic Computational and Experimental Study

    DEFF Research Database (Denmark)

    Hu, Qiang; Colmenares Rausseo, Luis César; Martinez, Umberto

    2015-01-01

    a combined computational and experimental study. It was found that Sb-dopant atoms prefer to segregate toward the ATO/Pt interface. The deposited Pt catalysts, interestingly, not only promote Sb segregation, but also suppress the occurrence of Sb3+ species, a charge carrier neutralizer at the interface...... to support future applications of ATO/Pt-based materials as possible cathodes for PEMFC applications with enhanced durability under practical applications....

  10. Single-Longitudinal-Mode In-GaAsSb/AlGaAsSb Lasers for Gas Sensing

    International Nuclear Information System (INIS)

    Barrios, P.; Gupta, J.; Lapointe, J.; Aers, G.; Storey, C.

    2009-01-01

    Regrowth-free gain-coupled Ga Sb-based Dfb lasers suitable for gas sensing were fabricated. Threshold currents for 2.4μm emission of 400μm-long Dfb devices were 45mA with a total output power of nearly 11mW in C W operation at 20 o C. (Author)

  11. Laser irradiation and thermal treatment inducing selective crystallization in Sb2O3-Sb2S3 glassy films

    Science.gov (United States)

    Avila, L. F.; Pradel, A.; Ribeiro, S. J. L.; Messaddeq, Y.; Nalin, M.

    2015-02-01

    The influence of both thermal treatment and laser irradiation on the structural and optical properties of films in the Sb2O3-Sb2S3 system was investigated. The films were prepared by RF-sputtering using glass compositions as raw materials. Irreversible photodarkening effect was observed after exposure the films to a 458 nm solid state laser. It is shown, for the first time, the use of holographic technique to measure "in situ", simultaneously and independently, the phase and amplitude modulations in glassy films. The films were also photo-crystallized and analysed "in situ" using a laser coupled to a micro-Raman equipment. Results showed that Sb2S3 crystalline phase was obtained after irradiation. The effect of thermal annealing on the structure of the films was carried out. Different from the result obtained by irradiation, thermal annealing induces the crystallization of the Sb2O3 phase. Photo and thermal induced effects on films were studied using UV-Vis and Raman spectroscopy, atomic force microscopy (AFM), thermal analysis (DSC), X-ray diffraction, scanning electron microscopy (MEV) and energy-dispersive X-ray spectroscopy (EDX).

  12. Epidemiology of burns

    NARCIS (Netherlands)

    Dokter, Jan

    2016-01-01

    The aim of this thesis is to understand the epidemiology, treatment and outcomes of specialized burn care in The Netherlands. This thesis is mainly based on historical data of the burn centre in Rotterdam from 1986, combined with historical data from the burn centres in Groningen and Beverwijk from

  13. Translational Epidemiology in Psychiatry

    Science.gov (United States)

    Weissman, Myrna M.; Brown, Alan S.; Talati, Ardesheer

    2012-01-01

    Translational research generally refers to the application of knowledge generated by advances in basic sciences research translated into new approaches for diagnosis, prevention, and treatment of disease. This direction is called bench-to-bedside. Psychiatry has similarly emphasized the basic sciences as the starting point of translational research. This article introduces the term translational epidemiology for psychiatry research as a bidirectional concept in which the knowledge generated from the bedside or the population can also be translated to the benches of laboratory science. Epidemiologic studies are primarily observational but can generate representative samples, novel designs, and hypotheses that can be translated into more tractable experimental approaches in the clinical and basic sciences. This bedside-to-bench concept has not been explicated in psychiatry, although there are an increasing number of examples in the research literature. This article describes selected epidemiologic designs, providing examples and opportunities for translational research from community surveys and prospective, birth cohort, and family-based designs. Rapid developments in informatics, emphases on large sample collection for genetic and biomarker studies, and interest in personalized medicine—which requires information on relative and absolute risk factors—make this topic timely. The approach described has implications for providing fresh metaphors to communicate complex issues in interdisciplinary collaborations and for training in epidemiology and other sciences in psychiatry. PMID:21646577

  14. The Epidemiology of Pheochromocytoma

    DEFF Research Database (Denmark)

    Ladefoged Ebbehøj, Andreas

    2017-01-01

    Pheochromocytoma and catecholamine secreting paraganglioma (PPGL) are exceedingly rare endocrine tumours, but remain a frequent diagnostic dilemma due to their potential life-threatening nature. Reliable data on the epidemiology of PPGL is lacking and no time trends in incidence rates (IR) have...

  15. Synthesis and crystal structure of Cd2SbBr2

    International Nuclear Information System (INIS)

    Reshetova, L.N.; Shevel'kov, A.V.; Popovkin, B.A.

    1999-01-01

    A new cadmium antimonidobromide, i.e. Cd 2 SbBr 2 , has been synthesized by the standard ampoule method. The compound is crystallized in monoclinic system of sp. gr. P2 1 :a=8.244 (1), b=9.920(1), c=8.492(1) A, Β=116.80(1) deg. Binuclear anions of Sb 2 4- (Sb-Sb 2.78 A), octahedrically surrounded by six cadmium atoms, are a basic specific feature of the structure. Octahedrons of Sb 2 Cd 6 , by collectivizing the equatorial vertices. form layers, the alternation mode of which is similar to the one described for cadmium and mercury arsenidochlorides

  16. In situ study of the formation kinetics of InSb quantum dots grown in an InAs(Sb) matrix

    International Nuclear Information System (INIS)

    Semenov, A. N.; Lyublinskaya, O. G.; Solov’ev, V. A.; Mel’tser, B. Ya.; Ivanov, S. V.

    2008-01-01

    Formation of InSb quantum dots grown in an InAs matrix by molecular-beam epitaxy that does not involve forced deposition of InSb is studied. Detection of intensity oscillations in the reflection of high-energy electron diffraction patterns was used to study in situ the kinetics of the formation of InSb quantum dots and an InAsSb wetting layer. The effects of the substrate temperature, the shutter operation sequence, and the introduction of growth interruptions on the properties of the array of InSb quantum dots are examined. Introduction of a growth interruption immediately after completing the exposure of the InAs surface to the antimony flux leads to a reduction in the nominal thickness of InSb and to an enhancement in the uniformity of the quantum-dot array. It is shown that, in the case of deposition of submonolayer-thickness InSb/InAs quantum dots, the segregation layer of InAsSb plays the role of the wetting layer. The Sb segregation length and segregation ratio, as well as their temperature dependences, are determined.

  17. Spondylolysis and spina bifida occulta in pediatric patients: prevalence study using computed tomography as a screening method.

    Science.gov (United States)

    Urrutia, Julio; Cuellar, Jorge; Zamora, Tomas

    2016-02-01

    The prevalence of spondylolysis reported from radiograph-based studies has been questioned in recent computed tomography (CT)-based studies in adults; however, no new data are available in pediatric patients. Spina bifida occulta (SBO), which has been associated to spondylolysis, may be increasing its prevalence, according to recent studies in adults in the last decades, but without new data in pediatric patients. We aimed to determine the prevalence of spondylolysis and SBO in pediatric patients using abdomen and pelvis CT as a screening tool. We studied 228 patients 4-15 years old (107 males), who were evaluated with abdomen and pelvis CT scans for reasons not related to the spine. The entire lumbo-sacral spine was evaluated to detect the presence of spondylolysis and SBO. We compared the prevalence of spondylolysis in patients with and without SBO. A logistic regression analysis was performed to determine the effect of age and sex as independent predictors of spondylolysis and SBO. The prevalence of spondylolysis was 3.5 % (1.1-5.9 %); 2/8 patients presented with olisthesis, both with grade I slip. The prevalence of SBO was 41.2 % (34.8-59.2 %) (94 patients). Spondylolysis was not more frequent in patients with SBO than in patients without SBO. Male sex and decreasing age independently predicted the presence of SBO, but not of spondylolysis. We observed a 3.5 % prevalence of spondylolysis and a 41.2 % prevalence of SBO. SBO was significantly more frequent in males and younger patients.

  18. Local structural environments of Ge doped in eutectic Sb-Te film before and after crystallization

    Science.gov (United States)

    Shin, Sang Yeol; Cheong, Byung-ki; Choi, Yong Gyu

    2018-06-01

    Electrical phase change device using the Ge-doped eutectic Sb-Te (e.g., Ge1Sb8Te2) film is known to exhibit improved energy efficiency thanks to lowered threshold voltage as well as decreased power consumption for the reset operation, as compared with Ge2Sb2Te5 film. Ge K-edge EXAFS analysis is employed in this study in an effort to elucidate such merits of Ge1Sb8Te2 film in connection with its local atomic arrangements. It is then verified that a Ge atom is four-fold coordinated in its nearest-neighboring shell both in the as-deposited and in the annealed films. It needs to be highlighted that approximately two Sb atoms constitute the Ge tetrahedral units in its amorphous state; however, after being crystallized, heteropolar Ge-Sb bonds hardly exist in this Ge1Sb8Te2 film. It has been known that crystallization temperature and activation energy for crystallization of this Ge1Sb8Te2 composition are greater than those of Ge2Sb2Te5 composition. In addition, these two phase change materials exhibit distinctly different crystallization mechanisms, i.e., nucleation-dominant for Ge2Sb2Te5 film but growth-dominant for Ge1Sb8Te2 film. These discrepancies in the crystallization-related properties are delineated in terms of the local structural changes verified from the present EXAFS analysis.

  19. The formation mechanisms and optical characteristics of GaSb quantum rings

    International Nuclear Information System (INIS)

    Lin, Wei-Hsun; Pao, Chun-Wei; Wang, Kai-Wei; Liao, Yu-An; Lin, Shih-Yen

    2013-01-01

    The growth mechanisms and optical characteristics of GaSb quantum rings (QRs) are investigated. Although As-for-Sb exchange is the mechanism responsible for the dot-to-ring transition, significant height difference between GaSb quantum dots (QDs) and QRs in a dot/ring mixture sample suggests that the dot-to-ring transition is not a spontaneous procedure. Instead, it is a rapid transition procedure as long as it initiates. A model is established to explain this phenomenon. Larger ring inner diameters and heights of the sample with longer post Sb soaking time suggest that As-for-Sb exchange takes places in both vertical and lateral directions. The decreasing ring densities, enlarged ring inner/outer diameters and eventually flat GaSb surfaces observed with increasing growth temperatures are resulted from enhanced adatom migration and As-for-Sb exchange with increasing growth temperatures

  20. Structural transition of (InSb)n clusters at n = 6-10

    Science.gov (United States)

    Lu, Qi Liang; Luo, Qi Quan; Huang, Shou Guo; Li, Yi De

    2016-10-01

    An optimization strategy combining global semi-empirical quantum mechanical search with all-electron density functional theory was adopted to determine the lowest energy structure of (InSb)n clusters with n = 6-10. A new structural growth pattern of the clusters was observed. The lowest energy structures of (InSb)6 and (InSb)8 were different from that of previously reported results. Competition existed between core-shell and cage-like structures of (InSb)8. The structural transition of (InSb)n clusters occurred at size n = 8-9. For (InSb)9 and (InSb)10 clusters, core-shell structure were more energetically favorable than the cage. The corresponding electronic properties were investigated.

  1. Simultaneous removal of Cd(II) and Sb(V) by Fe–Mn binary oxide: Positive effects of Cd(II) on Sb(V) adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ruiping [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Liu, Feng [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Hu, Chengzhi, E-mail: czhu@rcees.ac.cn [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); He, Zan [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Huijuan; Qu, Jiuhui [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2015-12-30

    Highlights: • Fe–Mn binary oxide achieves the simultaneous removal of Cd(II) and Sb(V). • Cd(II) at above 0.25 mmol/L improves Sb(V) adsorption onto FMBO. • Cd(II) improves more significant Sb(V) adsorption than Ca{sup 2+} and Mn{sup 2+}. • Sb(V) adsorption decreases whereas Cd(II) adsorption increases with elevated pH. • The increased ζ-potential and Cd(II)–Sb(V) precipitation favors Sb(V) adsorption. - Abstract: The coexistence of cadmium ion (Cd(II)) and antimonate (Sb(V)) creates the need for their simultaneous removal. This study aims to investigate the effects of positively-charged Cd(II) on the removal of negative Sb(V) ions by Fe–Mn binary oxide (FMBO) and associated mechanisms. The maximum Sb(V) adsorption density (Q{sub max,Sb(V)}) increased from 1.02 to 1.32 and 2.01 mmol/g in the presence of Cd(II) at 0.25 and 0.50 mmol/L. Cd{sup 2+} exhibited a more significant positive effect than both calcium ion (Ca{sup 2+}) and manganese ion (Mn{sup 2+}). Cd{sup 2+} showed higher affinity towards FMBO and increased its ζ-potential more significantly compared to Ca{sup 2+} and Mn{sup 2+}. The simultaneous adsorption of Sb(V) and Cd(II) onto FMBO can be achieved over a wide initial pH (pH{sub i}) range from 2 to 9, and Q{sub Sb(V)} decreases whereas Q{sub Cd(II)} increases with elevated pH{sub i}. Their combined values, as expressed by Q{sub Sb(V)+Cd(II)}, amount to about 2 mmol/g and vary slightly in the pH{sub i} range 4–9. FTIR and XPS spectra indicate the significant synergistic effect of Cd(II) on Sb(V) adsorption onto FMBO, and that little chemical valence transformation occurs. These results may be valuable for the treatment of wastewater with coexisting heavy metals such as Cd(II) and Sb(V).

  2. GaSb solar cells grown on GaAs via interfacial misfit arrays for use in the III-Sb multi-junction cell

    Science.gov (United States)

    Nelson, George T.; Juang, Bor-Chau; Slocum, Michael A.; Bittner, Zachary S.; Laghumavarapu, Ramesh B.; Huffaker, Diana L.; Hubbard, Seth M.

    2017-12-01

    Growth of GaSb with low threading dislocation density directly on GaAs may be possible with the strategic strain relaxation of interfacial misfit arrays. This creates an opportunity for a multi-junction solar cell with access to a wide range of well-developed direct bandgap materials. Multi-junction cells with a single layer of GaSb/GaAs interfacial misfit arrays could achieve higher efficiency than state-of-the-art inverted metamorphic multi-junction cells while forgoing the need for costly compositionally graded buffer layers. To develop this technology, GaSb single junction cells were grown via molecular beam epitaxy on both GaSb and GaAs substrates to compare homoepitaxial and heteroepitaxial GaSb device results. The GaSb-on-GaSb cell had an AM1.5g efficiency of 5.5% and a 44-sun AM1.5d efficiency of 8.9%. The GaSb-on-GaAs cell was 1.0% efficient under AM1.5g and 4.5% at 44 suns. The lower performance of the heteroepitaxial cell was due to low minority carrier Shockley-Read-Hall lifetimes and bulk shunting caused by defects related to the mismatched growth. A physics-based device simulator was used to create an inverted triple-junction GaInP/GaAs/GaSb model. The model predicted that, with current GaSb-on-GaAs material quality, the not-current-matched, proof-of-concept cell would provide 0.5% absolute efficiency gain over a tandem GaInP/GaAs cell at 1 sun and 2.5% gain at 44 suns, indicating that the effectiveness of the GaSb junction was a function of concentration.

  3. Three-Dimensional Reduced Graphene Oxide Coupled with Mn3O4 for Highly Efficient Removal of Sb(III) and Sb(V) from Water.

    Science.gov (United States)

    Zou, Jian-Ping; Liu, Hui-Long; Luo, Jinming; Xing, Qiu-Ju; Du, Hong-Mei; Jiang, Xun-Heng; Luo, Xu-Biao; Luo, Sheng-Lian; Suib, Steven L

    2016-07-20

    Highly porous, three-dimensional (3D) nanostructured composite adsorbents of reduced graphene oxides/Mn3O4 (RGO/Mn3O4) were fabricated by a facile method of a combination of reflux condensation and solvothermal reactions and systemically characterized. The as-prepared RGO/Mn3O4 possesses a mesoporous 3D structure, in which Mn3O4 nanoparticles are uniformly deposited on the surface of the reduced graphene oxide. The adsorption properties of RGO/Mn3O4 to antimonite (Sb(III)) and antimonate (Sb(V)) were investigated using batch experiments of adsorption isotherms and kinetics. Experimental results show that the RGO/Mn3O4 composite has fast liquid transport and superior adsorption capacity toward antimony (Sb) species in comparison to six recent adsorbents reported in the literature and summarized in a table in this paper. Theoretical maximum adsorption capacities of RGO/Mn3O4 toward Sb(III) and Sb(V) are 151.84 and 105.50 mg/g, respectively, modeled by Langmuir isotherms. The application of RGO/Mn3O4 was demonstrated by using drinking water spiked with Sb (320 μg/L). Fixed-bed column adsorption experiments indicate that the effective breakthrough volumes were 859 and 633 mL bed volumes (BVs) for the Sb(III) and Sb(V), respectively, until the maximum contaminant level of 5 ppb was reached, which is below the maximum limits allowed in drinking water according to the most stringent regulations. The advantages of being nontoxic, highly stable, and resistant to acid and alkali and having high adsorption capacity toward Sb(III) and Sb(V) confirm the great potential application of RGO/Mn3O4 in Sb-spiked water treatment.

  4. New uranium chalcoantimonates, RbU{sub 2}SbS{sub 8} and KU{sub 2}SbSe{sub 8}, with a polar noncentrosymmetric structure

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K S; Kanatzidis, M G

    1999-09-01

    The new compounds, RbU{sub 2}SbS{sub 8} and KU{sub 2}SbSe{sub 8}, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU{sub 2}SbS{sub 8} has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U{sup 4+} atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the a-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb{sup 3+} ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb{sup +} ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU{sub 2}SbSe{sub 8} has essentially the same structure as RbU{sub 2}SbS{sub 8}. However, Sb{sup 3+} and K{sup +} ions appear disordered in every other layer resulting in a different unit cell. RbU{sub 2}SbS{sub 8} is a semiconductor with a band gap of 1.38 eV. The band gap of KU{sub 2}SbSe{sub 8} could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5--1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU{sub 2}SbS{sub 8} at 479 cm{sup {minus}1} and the diselenide stretching vibration in KU{sub 2}SbSe{sub 8} at 252 cm{sup {minus}1}. Magnetic susceptibility measurements indicate the presence of U{sup 4+} centers in the compounds. The compounds do not melt below 1,000 C under vacuum.

  5. Epidemiology applied to health physics

    International Nuclear Information System (INIS)

    1983-01-01

    The technical program of the mid-year meeting of the Health Physics Society, entitled Epidemiology Applied to Health physics, was developed to meet three objectives: (1) give health physicists a deeper understanding of the basics of epidemiological methods and their use in developing standards, regulations, and criteria and in risk assessment; (2) present current reports on recently completed or on-going epidemiology studies; and (3) encourage greater interaction between the health physics and epidemiology disciplines. Included are studies relating methods in epidemiology to radiation protection standards, risk assessment from exposure to bone-seekers, from occupational exposures in mines, mills and nuclear facilities, and from radioactivity in building materials

  6. Investigation of environmental friendly Te-free SiSb material for applications of phase-change memory

    International Nuclear Information System (INIS)

    Zhang Ting; Song Zhitang; Liu Bo; Feng Songlin

    2008-01-01

    Te-free environmental friendly Si x Sb 100−x phase-change materials are investigated. The binary material, which is compatible with the complementary metal-oxide-semiconductor manufacturing process, is outstanding in various properties. Si x Sb 100−x shows a much better data retention as compared with Ge 2 Sb 2 Te 5 . The density change for Si 10 Sb 90 and Si 16 Sb 84 is only about 3% and 3.8%, respectively. The failure times for Si 10 Sb 90 and Si 16 Sb 84 are about 10 3 and 10 6 times longer than that of Ge 2 Sb 2 Te 5 at 110 °C. The crystallization temperature of Si x Sb 100−x increases with silicon content within the material. Si x Sb 100−x materials are good candidates for the phase-change memory applications

  7. Epidemiology and ionizing radiations

    International Nuclear Information System (INIS)

    Bourguignon, M.; Masse, R.; Slama, R.; Spira, A.; Timarche, M.; Laurier, D.; Billon, S.; Rogel, A.; Telle Lamberton, M.; Catelinois, O.; Thierry, I.; Grosche, B.; Ron, E.; Vathaire, F. de; Cherie Challine, L.; Donadieu, J.; Pirard, Ph.; Bloch, J.; Setbon, M.

    2004-01-01

    The ionizing radiations have effects on living being. The determinist effects appear since a threshold of absorbed dose of radiation is reached. In return, the stochastic effects of ionizing radiations are these ones whom apparition cannot be described except in terms of probabilities. They are in one hand, cancers and leukemia, on the other hand, lesions of the genome potentially transmissible to the descendants. That is why epidemiology, defined by specialists as the science that studies the frequency and distribution of illness in time and space, the contribution of factors that determine this frequency and this distribution among human populations. This issue gathers and synthesizes the knowledge and examines the difficulties of methodologies. It allows to give its true place to epidemiology. (N.C.)

  8. Epidemiology of Gout

    Science.gov (United States)

    Choi, Hyon

    2014-01-01

    Synopsis Gout is the most prevalent inflammatory arthritis in men. The findings of several epidemiological studies from a diverse range of countries suggest that the prevalence of gout has risen over the last few decades. Whilst incidence data are scarce, data from the US suggests that the incidence of gout is also rising. Evidence from prospective epidemiological studies has confirmed dietary factors (animal purines, alcohol and fructose), obesity, the metabolic syndrome, hypertension, diuretic use, and chronic kidney disease as clinically relevant risk factors for hyperuricemia and gout. Low-fat dairy products, coffee, and vitamin C appear to have a protective effect. Further prospective studies are required to examine other proposed risk factors for hyperuricaemia and gout such as the use of β-blockers and angiotension-II receptor antagonists (other than losartan), obstructive sleep apnoea, and osteoarthritis, and putative protective factors such as calcium-channel blockers and losartan. PMID:24703341

  9. Epidemiological studies on syncope

    DEFF Research Database (Denmark)

    Ruwald, Martin Huth

    2013-01-01

    of the patients play an essential role. In epidemiology these factors have major impact on the outcome of the patients. Until recently, even the definition of syncope differed from one study to another which has made literature reviews difficult. Traditionally the data on epidemiology of syncope has been taken...... from smaller studies from different clinical settings with wide differences in patient morbidity. Through the extensive Danish registries we examined the characteristics and prognosis of the patients hospitalized due to syncope in a nationwide study. The aims of the present thesis were to investigate......, prevalence and cardiovascular factors associated with the risk of syncope, 4) the prognosis in healthy individuals discharged after syncope, and 5) the prognosis of patients after syncope and evaluation of the CHADS2 score as a tool for short- and long-term risk prediction. The first studies of the present...

  10. Properties of the low-lying levels of 122Sb

    International Nuclear Information System (INIS)

    Gunsteren, W.F. van; Rabenstein, D.

    1977-01-01

    Nanosecond lifetimes of low-lying levels in the doubly odd nucleus 122 Sb have been measured. On the basis of these results and of already published experimental material, spins and parities for most of the low-lying states are proposed. A simple theoretical description of this nucleus is presented. The model used is that of a proton coupled to a number projected neutron quasiparticle wave function, assuming a Z=N=50 core. The spectrum and transition rates were calculated in a shell model space consisting of eight subshells and using a renormalized Schiffer interaction. The shell model parameters were derived from adjadent nuclei. Good agreement with the experimental level scheme is found. Also the gamma decay properties can be accounted for rather well. Spectroscopic factors for the one-neutron transfer reactions leading to 122 Sb are predicted. Their measurement with high resolution techniques would be a helpful test for the interpretations given. (orig.) [de

  11. Optical nonlinear absorption characteristics of Sb2Se3 nanoparticles

    Science.gov (United States)

    Muralikrishna, Molli; Kiran, Aditha Sai; Ravikanth, B.; Sowmendran, P.; Muthukumar, V. Sai; Venkataramaniah, Kamisetti

    2014-04-01

    In this work, we report for the first time, the nonlinear optical absorption properties of antimony selenide (Sb2Se3) nanoparticles synthesized through solvothermal route. X-ray diffraction results revealed the crystalline nature of the nanoparticles. Electron microscopy studies revealed that the nanoparticles are in the range of 10 - 40 nm. Elemental analysis was performed using EDAX. By employing open aperture z-scan technique, we have evaluated the effective two-photon absorption coefficient of Sb2Se3 nanoparticles to be 5e-10 m/W at 532 nm. These nanoparticles exhibit strong intensity dependent nonlinear optical absorption and hence could be considered to have optical power limiting applications in the visible range.

  12. GeSbTe deposition for the PRAM application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Junghyun [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Choi, Sangjoon [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Lee, Changsoo [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Kang, Yoonho [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Kim, Daeil [School of Materials Science and Engineering. University of Ulsan, San 29, Mugeo-Dong, Nam-Gu, Ulsan 680-749 (Korea, Republic of)]. E-mail: dkim84@mail.ulsan.ac.kr

    2007-02-15

    GeSbTe (GST) chalcogenide thin films for the phase-change random access memory (PRAM) were deposited by an atomic layer deposition (ALD) process. New precursors for GST thin films made with an ALD process were synthesized. Among the synthesized precursors, Ge(N(CH{sub 3}){sub 2}){sub 4}, Sb(N(CH{sub 3}){sub 2}){sub 4}, and Te(i-Pr){sub 2} (i-Pr = iso-propyl) were selected. Using the above precursors, GST thin films were deposited using an H{sub 2} plasma-assisted ALD process. Film resistivity abruptly changed after an N{sub 2} annealing process above a temperature of 350 deg. C. Cross-sectional scanning electron microscope (SEM) photographs of the GST films on the patterned substrate with aspect ratio of 7 shows that the step coverage is about 90%.

  13. Microalloying with Cd of Antifriction Sn-Sb-Cu Alloys

    Directory of Open Access Journals (Sweden)

    Cinca Ionel Lupinca

    2012-09-01

    Full Text Available In the case of bimetallic sliding linings with superior technological characteristics, the use of an antifriction ally is imposed an alloy of the type Sn-Sb-Cu, which possesses a high adherence to the steel stand and a high durability in exploitation. For this reason we use the microalloying of the antifriction alloy with cadmium. The microalloying with Cd of antifriction alloys Sn-Sb-Cu determines an increase of the adhesion property of the antifriction alloy on the steel stand. The steel stand is previously subjected to a process of degreasing with ZnCl2 and washing so that is can later be subjected to a thermal-chemical treatment of tinning.

  14. The leukemias: Epidemiologic aspects

    International Nuclear Information System (INIS)

    Linet, M.S.

    1984-01-01

    Particularly geared to physicians and cancer researchers, this study of the epidemiology and etiology of leukemia analyzes the four major leukemia subtypes in terms of genetic and familial determinant factors and examines the incidence, distribution and frequency of reported leukemia clusters. Linet discusses the connection between other types of malignancies, their treatments, and the subsequent development of leukemia and evaluates the impact on leukemia onset of such environmental factors as radiation therapy, drugs, and occupational hazards

  15. Worldwide Report, Epidemiology

    Science.gov (United States)

    1985-11-22

    caused by ingesting eggs of the pork tapeworm, Taenia solium . It has been described as the most com- mon parasitic disease of the central nervous...rather difficult to detect in stool specimens and at this stage it is impossible to distinguish between T. solium and T. saginata eggs either by...Knowledge and Perspectives, pp. 25-38. Academic Press, New York. 12. Pawlowskz S. (1982). Epidemiology and prevention of Taenia saginata infec- tion. In

  16. Epidemiology and moral philosophy.

    OpenAIRE

    Westrin, C G; Nilstun, T; Smedby, B; Haglund, B

    1992-01-01

    To an increasing extent ethical controversies affect and sometimes obstruct public health work and epidemiological research. In order to improve communication between the concerned parties a model for identification and analysis of ethical conflicts in individual-based research has been worked out in co-operation between epidemiologists and moral philosophers. The model has two dimensions. One dimension specifies relevant ethical principles (as beneficence, non-maleficence, autonomy and justi...

  17. Defect-induced magnetic structure of CuMnSb

    Czech Academy of Sciences Publication Activity Database

    Máca, František; Kudrnovský, Josef; Drchal, Václav; Turek, I.; Stelmakhovych, O.; Beran, Přemysl; Llobet, A.; Martí, Xavier

    2016-01-01

    Roč. 94, č. 9 (2016), 1-9, č. článku 094407. ISSN 2469-9950 R&D Projects: GA ČR GB14-37427G Institutional support: RVO:68378271 ; RVO:61389005 Keywords : CuMnSb * electronic structure * defects * magnetic order * ab initio calculations * neutron diffraction analysis Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

  18. Magneto-optical effect in Mn-Sb thin films

    International Nuclear Information System (INIS)

    Attaran, E.; Sadabadi, M.

    2003-01-01

    The magneto-optic Kerr and Faraday effect of Mn-Sb thin films have been studied. The single and multilayer of this film have grown on glass substrate by evaporation. The optical rotation of linear polarized light has been measured by an optical hysteresis plotter in a I/O converter amplifier circuit. Our results indicate a polar Kerr rotation up to 0.5 degree and in a double Mn S b this rotation research to maximum

  19. Temperature Variation of the Magnetic Structure of HoSb

    DEFF Research Database (Denmark)

    Andersen, Nils Axel; Kjems, Jørgen; Vogt, O.

    1980-01-01

    Neutron diffraction has been used to show that the magnetic moment vector in the antiferromagnet HoSb changes direction as a function of temperature below TN=5.7K. The experimental results are in qualitative agreement with a recent theoretical prediction by Jensen et al. (1980) which ascribe the ...... the changing directions to a competition between the crystal fields and the dipolar interactions....

  20. Approaching the Hole Mobility Limit of GaSb Nanowires.

    Science.gov (United States)

    Yang, Zai-xing; Yip, SenPo; Li, Dapan; Han, Ning; Dong, Guofa; Liang, Xiaoguang; Shu, Lei; Hung, Tak Fu; Mo, Xiaoliang; Ho, Johnny C

    2015-09-22

    In recent years, high-mobility GaSb nanowires have received tremendous attention for high-performance p-type transistors; however, due to the difficulty in achieving thin and uniform nanowires (NWs), there is limited report until now addressing their diameter-dependent properties and their hole mobility limit in this important one-dimensional material system, where all these are essential information for the deployment of GaSb NWs in various applications. Here, by employing the newly developed surfactant-assisted chemical vapor deposition, high-quality and uniform GaSb NWs with controllable diameters, spanning from 16 to 70 nm, are successfully prepared, enabling the direct assessment of their growth orientation and hole mobility as a function of diameter while elucidating the role of sulfur surfactant and the interplay between surface and interface energies of NWs on their electrical properties. The sulfur passivation is found to efficiently stabilize the high-energy NW sidewalls of (111) and (311) in order to yield the thin NWs (i.e., 40 nm in diameters) would grow along the most energy-favorable close-packed planes with the orientation of ⟨111⟩, supported by the approximate atomic models. Importantly, through the reliable control of sulfur passivation, growth orientation and surface roughness, GaSb NWs with the peak hole mobility of ∼400 cm(2)V s(-1) for the diameter of 48 nm, approaching the theoretical limit under the hole concentration of ∼2.2 × 10(18) cm(-3), can be achieved for the first time. All these indicate their promising potency for utilizations in different technological domains.

  1. Thermoelectric nanocrystalline YbCoSb laser prepared layers

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Zeipl, Radek; Kocourek, Tomáš; Remsa, Jan; Navrátil, Jiří

    2016-01-01

    Roč. 122, č. 3 (2016), s. 1-5, č. článku 155. ISSN 0947-8396 R&D Projects: GA ČR(CZ) GA13-33056S Institutional support: RVO:68378271 ; RVO:61389013 Keywords : nanocrystalline YbCoSb * thermoelectric layers * pulsed laser deposition Subject RIV: BM - Solid Matter Physics ; Magnetism; CA - Inorganic Chemistry (UMCH-V) Impact factor: 1.455, year: 2016

  2. Thermoelectric properties of RuSb2Te ternary skutterudites

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Jiří; Plecháček, T.; Drašar, Č.; Laufek, F.

    2013-01-01

    Roč. 42, č. 7 (2013), s. 1864-1869 ISSN 0361-5235 R&D Projects: GA ČR GAP108/10/1315 Institutional support: RVO:61389013 Keywords : RuSb2Te * ternary skutterudite * doping Subject RIV: CA - Inorganic Chemistry Impact factor: 1.675, year: 2013 http://link.springer.com/article/10.1007/s11664-012-2451-5

  3. High-spin, multiparticle isomers in 121,123Sb

    International Nuclear Information System (INIS)

    Jones, G. A.; Walker, P. M.; Podolyak, Zs.; Cullen, I. J.; Garnsworthy, A. B.; Liu, Z.; Thompson, N. J.; Williams, S. J.; Zhu, S.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Seweryniak, D.; Carroll, J. J.; Chakrawarthy, R. S.; Hackman, G.; Chowdhury, P.; Dracoulis, G. D.; Lane, G. J.; Kondev, F. G.

    2008-01-01

    Isomers in near-spherical Z=51, antimony isotopes are reported here for the first time using fusion-fission reactions between 27 Al and a pulsed 178 Hf beam of energy, 1150 MeV. γ rays were observed from the decay of isomeric states with half-lives, T 1/2 =200(30) and 52(3)μs, and angular momenta I=((25/2)) and I π =(23/2) + , in 121,123 Sb, respectively. These states are proposed to correspond to ν(h (11/2) ) 2 configurations, coupled to an odd d (5/2) or g (7/2) proton. Nanosecond isomers were also identified at I π =(19/2) - [T 1/2 =8.5(5) ns] in 121 Sb and I π =((15/2) - ) [T 1/2 =37(4) ns] in 123 Sb. Information on spins and parities of states in these nuclei was obtained using a combination of angular correlation and intensity-balance measurements. The configurations of states in these nuclei are discussed using a combination of spin/energy systematics and shell-model calculations for neighboring tin isotones and antimony isotopes

  4. Grain boundary engineering with nano-scale InSb producing high performance InxCeyCo4Sb12+z skutterudite thermoelectrics

    Directory of Open Access Journals (Sweden)

    Han Li

    2017-12-01

    Full Text Available Thermoelectric semiconductors based on CoSb3 hold the best promise for recovering industrial or automotive waste heat because of their high efficiency and relatively abundant, lead-free constituent elements. However, higher efficiency is needed before thermoelectrics reach economic viability for widespread use. In this study, n-type InxCeyCo4Sb12+z skutterudites with high thermoelectric performance are produced by combining several phonon scattering mechanisms in a panoscopic synthesis. Using melt spinning followed by spark plasma sintering (MS-SPS, bulk InxCeyCo4Sb12+z alloys are formed with grain boundaries decorated with nano-phase of InSb. The skutterudite matrix has grains on a scale of 100–200 nm and the InSb nano-phase with a typical size of 5–15 nm is evenly dispersed at the grain boundaries of the skutterudite matrix. Coupled with the presence of defects on the Sb sublattice, this multi-scale nanometer structure is exceptionally effective in scattering phonons and, therefore, InxCeyCo4Sb12/InSb nano-composites have very low lattice thermal conductivity and high zT values reaching in excess of 1.5 at 800 K.

  5. Synthesis, characterization and photovoltaic properties of Mn-doped Sb2S3 thin film

    Directory of Open Access Journals (Sweden)

    Horoz Sabit

    2018-03-01

    Full Text Available Synthesis and characterization of Mn-doped Sb2S3 thin films (TFs prepared by chemical bath deposition (CBD at room temperature have been documented and their structural, optical, morphological, magnetic and photovoltaic properties have been examined for the first time. Their structural properties reveal that the Mn-doped Sb2S3 TF has an orthorhombic phase structure of Sb2S3, and that the grain size of the Mn-doped Sb2S3 TF (72.9 nm becomes larger than that of undoped Sb2S3 TF (69.3 nm. It has been observed that Mn content causes the Sb2S3 TF band gap to decrease. This situation clearly correlates with band tailing due to the impurities that are involved. The morphological properties have revealed that the shape of the Mn-doped Sb2S3 TF is more uniform than the shape of its undoped counterpart. The study on its magnetic properties has demonstrated that the Mn-doped Sb2S3 TF exhibits paramagnetic behavior. Its paramagnetic Curie-Weiss temperature was found to be -4.1 K. This result suggests that there is an anti-ferromagnetic interaction between Mn moments in the Mn-doped Sb2S3 TF. Incident photon to electron conversion efficiency (IPCE and J-V measurements were also carried out for the Mn-doped Sb2S3 TF for the first time. The results have indicated that the Mn-doped Sb2S3 TF can be utilized as a sensitizer to improve the performance of solar cells. Another important observation on the photovoltaic properties of Mn-doped Sb2S3 TF is that the spectral response range is wider than that of undoped Sb2S3 TF. Our study suggests that the introduction of dopant could serve as an effective means of improving the device performance of solar cells.

  6. Structure and Chemical Bond of Thermoelectric Ce-Co-Sb Skutterudites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The correlations among composition,structure,chemical bond and thermoelectric property of skutterudites CoSb3 and CeCo5Fe3Sb12 have been studied by using density function and discrete variation (DFT-DVM) method.Three models for this study were proposed and calculated by which the "rattling" pattern was described.Model 1 is with Ce in the center,model 2 is with Ce away the center and near to Sb,and model 3 is also with Ce away the center but near to Fe.The calculated results show that in model 3,the ionic bond is the strongest,but the covalent bond is the weakest.Due to the different changes between ionic and covalent bond,there is less difference in the stability among the models 1,2 and 3.Therefore,these different models can exist at the same time,or can translate from one to another more easily.In other words,the "rattling" pattern has taken place.Unfilled model of CoSb3,without Ce and Fe,is called model 4.The covalent bond of Co-Sb or Fe-Sb in models 1,2 and 3 is weaker than that of Co-Sb in model 4,as some electrical cloud of Sb takes part in the covalent bond of Ce-Sb in the filled models.The result is consistent with the experimental result that the thermal conductivity of CeCo5Fe3Sb12 is lower than that of CoSb3,and the thermoelectric property of CeCo5Fe3Sb12 is superior to that of CoSb3.

  7. Formation of the InAs-, InSb-, GaAs-, and GaSb-polished surface

    Science.gov (United States)

    Levchenko, Iryna; Tomashyk, Vasyl; Stratiychuk, Iryna; Malanych, Galyna; Korchovyi, Andrii; Kryvyi, Serhii; Kolomys, Oleksandr

    2018-04-01

    The features of the InAs, InSb, GaAs, and GaSb ultra-smooth surface have been investigated using chemical-mechanical polishing with the (NH4)2Cr2O7-HBr-CH2(OH)CH2(OH)-etching solutions. The etching rate of the semiconductors has been measured as a function of the solution saturation by organic solvent (ethylene glycol). It was found that mechanical effect significantly increases the etching rate from 1.5 to 57 µm/min, and the increase of the organic solvent concentration promotes the decrease of the damaged layer-removing rate. According to AFM, RS, HRXRD results, the treatment with the (NH4)2Cr2O7-HBr-ethylene glycol solutions produces the clean surface of the nanosize level (R a < 0.5 nm).

  8. Short-wave infrared barriode detectors using InGaAsSb absorption material lattice matched to GaSb

    Energy Technology Data Exchange (ETDEWEB)

    Craig, A. P.; Percy, B.; Marshall, A. R. J. [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Jain, M. [Amethyst Research Ltd., Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP (United Kingdom); Wicks, G.; Hossain, K. [Amethyst Research, Inc., 123 Case Circle, Ardmore, Oklahoma 73401 (United States); Golding, T. [Amethyst Research Ltd., Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP (United Kingdom); Amethyst Research, Inc., 123 Case Circle, Ardmore, Oklahoma 73401 (United States); McEwan, K.; Howle, C. [Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ (United Kingdom)

    2015-05-18

    Short-wave infrared barriode detectors were grown by molecular beam epitaxy. An absorption layer composition of In{sub 0.28}Ga{sub 0.72}As{sub 0.25}Sb{sub 0.75} allowed for lattice matching to GaSb and cut-off wavelengths of 2.9 μm at 250 K and 3.0 μm at room temperature. Arrhenius plots of the dark current density showed diffusion limited dark currents approaching those expected for optimized HgCdTe-based detectors. Specific detectivity figures of around 7×10{sup 10} Jones and 1×10{sup 10} Jones were calculated, for 240 K and room temperature, respectively. Significantly, these devices could support focal plane arrays working at higher operating temperatures.

  9. Measurement of the Auger lifetime in GaInAsSb/GaSb heterostructures using the photoacoustic technique

    International Nuclear Information System (INIS)

    Riech, I.; Gomez-Herrera, M. L.; Diaz, P.; Mendoza-Alvarez, J. G.; Herrera-Perez, J. L.; Marin, E.

    2001-01-01

    We have studied Ga x In 1-x As y Sb 1-y /GaSb heterostructures for x=0.84 and y=0.14 using the photoacoustic technique with the heat transmission configuration. A theoretical model, which includes all the possible nonradiative recombination mechanisms that contribute to heat generation, was developed to calculate the photoacoustic signal for this type of heterostructure. The Auger recombination lifetime τ Auger was determined by fitting our experimental results to the calculated frequency dependence of the theoretical photoacoustic signal. The obtained value for τ Auger is compatible with those reported in the literature for semiconductors with band-gap energies below and above 0.5 eV, the energy region where there is a lack of experimental τ Auger values. Copyright 2001 American Institute of Physics

  10. Effects of Sb-doping on the formation of (K, Na)(Nb, Sb)O3 solid solution under hydrothermal conditions

    International Nuclear Information System (INIS)

    Su Likui; Zhu Kongjun; Bai Lin; Qiu Jinhao; Ji Hongli

    2010-01-01

    (K, Na)(Nb, Sb)O 3 (KNNS) lead-free peizoceramic powders were successfully synthesized by hydrothermal treatment at 240 o C for 8 h using the KOH, NaOH, Nb 2 O 5 and Sb 2 O 3 as raw materials. Effects of Sb-doping on the crystal structure and morphology of the as-prepared powders were investigated by powder X-ray diffraction (XRD), Raman spectra (Raman), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The Sb element was successfully doped into the alkaline niobate perovskite structure to form crystalline (K 0.7 Na 0.3 )(Nb 0.95 Sb 0.05 )O 3 lead-free piezoelectric ceramic powder, which has a hexagonal morphology due to the aggregation growth of small grains. Phase and morphology evolutions with the reaction time were also studied, and a possible formation mechanism was proposed.

  11. CRYSTAL-QUASICHEMICAL ANALYSIS OF DEFECT SUBSYSTEM OF DOPED PbTe: Sb CRYSTALS AND Pb-Sb-Te SOLID SOLUTIONS

    Directory of Open Access Journals (Sweden)

    D.M. Freik

    2014-05-01

    Full Text Available Within crystalquasichemical formalism models of point defects of crystals in the Pb-Sb-Te system were specified. Based on proposed crystalquasichemical formulae of antimony doped crystals PbTe:Sb amphoteric dopant effect was explained. Mechanisms of solid solution formation for РbТе-Sb2Те3: replacement of antimony ions lead sites  with the formation of cation vacancies  (I or neutral interstitial tellurium atoms  (II were examined. Dominant point defects in doped crystals PbTe:Sb and РbТе-Sb2Те3 solid solutions based on p-PbTe were defined. Dependences of concentration of dominant point defects, current carriers and Hall concentration on content of dopant compound and the initial deviation from stoichiometry in the basic matrix were calculated.

  12. Physics of bandgap formation in Cu-Sb-Se based novel thermoelectrics: the role of Sb valency and Cu d levels.

    Science.gov (United States)

    Do, Dat; Ozolins, Vidvuds; Mahanti, S D; Lee, Mal-Soon; Zhang, Yongsheng; Wolverton, C

    2012-10-17

    In this paper we discuss the results of ab initio electronic structure calculations for Cu(3)SbSe(4) (Se4) and Cu(3)SbSe(3) (Se3), two narrow bandgap semiconductors of thermoelectric interest. We find that Sb is trivalent in both the compounds, in contrast to a simple nominal valence (ionic) picture which suggests that Sb should be 5 + in Se4. The gap formation in Se4 is quite subtle, with hybridization between Sb 5s and the neighboring Se 4s, 4p orbitals, position of Cu d states, and non-local exchange interaction, each playing significant roles. Thermopower calculations show that Se4 is a better p-type system. Our theoretical results for Se4 agree very well with recent experimental results obtained by Skoug et al (2011 Sci. Adv. Mater. 3 602).

  13. High-Temperature Characteristics of an InAsSb/AlAsSb n+Bn Detector

    Science.gov (United States)

    Ting, David Z.; Soibel, Alexander; Höglund, Linda; Hill, Cory J.; Keo, Sam A.; Fisher, Anita; Gunapala, Sarath D.

    2016-09-01

    The high-temperature characteristics of a mid-wavelength infrared (MWIR) detector based on the Maimon-Wicks InAsSb/AlAsSb nBn architecture was analyzed. The dark current characteristics are examined in reference to recent minority carrier lifetime results. The difference between the responsivity and absorption quantum efficiency (QE) at shorter wavelengths is clarified in terms of preferential absorption of higher-energy photons in the top contact layer, which cannot provide reverse-bias photo-response due to the AlAsSb electron blocking layer and strong recombination. Although the QE does not degrade when the operating temperature increases to 325 K, the turn-on bias becomes larger at higher temperatures. This behavior was originally attributed to the change in the valence band alignment between the absorber and top contact layers caused by the shift in Fermi level with temperature. In this work, we demonstrated the inadequacy of the original description, and offer a more likely explanation based on temperature-dependent band-bending effects.

  14. TANK 40 FINAL SB4 CHEMICAL CHARACTERIZATION RESULTS

    International Nuclear Information System (INIS)

    Best, J.

    2008-01-01

    A sample of Sludge Batch 4 (SB4) was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). This sample was also analyzed for elemental and chemical composition including noble metals. These analyses along with the WAPS analyses will help define the composition of the sludge currently in Tank 40 which is currently being fed to DWPF and will become part of Sludge Batch 5 (SB5). At SRNL the 3-L Tank 40 SB4 sample was transferred from the shipping container into a 4-L vessel and solids allowed to settle overnight. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 280 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO 3 /HCl in sealed Teflon(reg s ign) vessels and four in Na 2 O 2 using Zr crucibles. Due to the use of Zr crucibles and Na in the peroxide fusions, Na and Zr cannot be determined from this preparation. Three glass standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted and submitted to Analytical Development (AD) for inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma-mass spectrometry (ICP-MS) analysis, and cold vapor atomic absorption (CV-AA) analysis. Equivalent dilutions of the peroxide fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB4 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES and ICP-MS. Weighted dilutions of slurry were submitted for ion chromatography (IC), total inorganic carbon/total organic carbon (TIC/TOC), and total base analyses. A sample of Tank 40 SB4 decant was collected by carefully removing the supernate phase

  15. [Ultrasound measurement of fetal posterior fossa at 11 to 13⁺⁶ gestational weeks for screening open spina bifida].

    Science.gov (United States)

    Qin, Feng-Zhen; Li, Sheng-Li; Wen, Hua-Xuan; Ouyang, Yu-Rong; Zheng, Qiong; Bi, Jing-Ru

    2014-06-01

    To establish the normal reference ranges of transabdominal ultrasound measurements of the posterior fossa structure in fetuses at 11 to 13⁺⁶ gestational weeks and explore their clinical value in screening open spina bifida (OSB). Between January, 2013 and September, 541 randomly selected normal fetuses underwent nuchal translucency at the gestational age 11 to 13⁺⁶ weeks. The parameters of the posterior fossa were measured in mid-sagittal view of the fetal face and the axial view of the transverse cerebellum insonated through the anterior fontanel by transabdominal ultrasound to establish the normal reference ranges. The measurements were obtained from 3 fetuses with OSB for comparison with the reference ranges. In normal fetuses, the parameters of the posterior fossa measured in the two views showed no significant differences (P>0.05). Two high echogenic lines were observed in normal fetuses, as compared with one in fetuses with OSB representing the posterior border of the brain stem and the anterior border of the fourth ventricle. The line between the posterior border of the fourth ventricle and the anterior border of the cisterna magna was not displayed in fetuses with OSB. The anteroposterior diameters of the brain stem, the fourth ventricle, and cisterna magna all increased in positive correlation with the crown-lump length in normal fetuses. In the 3 OSB fetuses, the anteroposterior diameter of the brain stem exceeded the 95th percentile and the anteroposterior diameter of fourth ventrical-cisterner magena was below the 5th percentile of the reference range for CRL; the brain stem to fourth ventrical-cisterner magena anteroposterior diameter ratio was increased to above 1. The established normal reference ranges of the parameters of fetal posterior fossa may provide assistance in early OSB detection. The absence of the posterior border of the fourth ventricle and the anterior border of the cisterna magna and a brainstem to fourth ventrical

  16. Thermodynamics of (Ga, In)-Sb-O-Si and impact on dewetting process

    Energy Technology Data Exchange (ETDEWEB)

    Sylla, L. [Cyberstar, Echirolles (France); Duffar, T. [SIMaP-EPM, Saint Martin d' Heres (France)

    2011-11-15

    A thermodynamic study is performed for the systems (Ga or In)-Sb-O-Si in order to better understand the difference observed during dewetting experiments of GaSb and InSb in silica ampoules. Results show that the melts can be considered as non reactive toward silica. When the atmosphere is clean ({<=}1 ppm O{sub 2}), no oxide is formed, while, under oxidising atmosphere, oxides exist above the melting point of the antimonide and are known to increase the wetting angle of the melt on the crucible. However the temperature range for oxide stability is smaller in the case of InSb and this may explain why dewetting is easy for GaSb in presence of oxygen, while it is difficult for InSb. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Three dimensional atom probe imaging of GaAsSb quantum rings

    International Nuclear Information System (INIS)

    Beltran, A.M.; Marquis, E.A.; Taboada, A.G.; Ripalda, J.M.; Garcia, J.M.; Molina, S.I.

    2011-01-01

    Unambiguous evidence of ring-shaped self-assembled GaSb nanostructures grown by molecular beam epitaxy is presented on the basis of atom-probe tomography reconstructions and dark field transmission electron microscopy imaging. The GaAs capping process causes a strong segregation of Sb out of the center of GaSb quantum dots, leading to the self-assembled GaAs x Sb 1-x quantum rings of 20-30 nm in diameter with x∼0.33. -- Highlights: → Atom-probe tomography resolves QR morphology of GaSb self-assembled GaSb buried nanostructures. → From atom-probe tomography compositional distribution has been obtained. → Strong segregation and morphological changes are observed with respect to uncapped QR.

  18. Enhanced photovoltaic performance of Sb2S3-sensitized solar cells through surface treatments

    Science.gov (United States)

    Ye, Qing; Xu, Yafeng; Chen, Wenyong; Yang, Shangfeng; Zhu, Jun; Weng, Jian

    2018-05-01

    Efficient antimony sulfide (Sb2S3)-sensitized solar cells were obtained by a sequential treatment with thioacetamide (TA) and 1-decylphosphonic acid (DPA). Compared with the untreated Sb2S3-sensitized solar cells, the power conversion efficiency of the treated Sb2S3 solar cells was improved by 1.80% to 3.23%. The TA treatment improved the Sb2S3 films by reducing impurities and decreasing the film's surface defects, which inhibited the emergence of recombination centers. The DPA treatment reduced the recombination between hole transport materials (HTMs) and the Sb2S3. Therefore, we have presented an efficient strategy to improve the performance of Sb2S3-sensitized solar cells.

  19. Worldwide epidemiology of fibromyalgia.

    Science.gov (United States)

    Queiroz, Luiz Paulo

    2013-08-01

    Studying the epidemiology of fibromyalgia (FM) is very important to understand the impact of this disorder on persons, families and society. The recent modified 2010 classification criteria of the American College of Rheumatology (ACR), without the need of tender points palpation, allows that larger and nationwide surveys may be done, worldwide. This article reviews the prevalence and incidence studies done in the general population, in several countries/continents, the prevalence of FM in special groups/settings, the association of FM with some sociodemographic characteristics of the population, and the comorbidity of FM with others disorders, especially with headaches.

  20. Epidemiology of Posttraumatic Osteoarthritis.

    Science.gov (United States)

    Thomas, Abbey C; Hubbard-Turner, Tricia; Wikstrom, Erik A; Palmieri-Smith, Riann M

    2017-06-02

    Osteoarthritis is a leading cause of disability whose prevalence and incidence continue to increase. History of joint injury represents an important risk factor for posttraumatic osteoarthritis and is a significant contributor to the rapidly growing percentage of the population with osteoarthritis. This review will present the epidemiology associated with posttraumatic osteoarthritis, with particular emphasis on the knee and ankle joints. It is important to understand the effect of posttraumatic osteoarthritis on the population so that sufficient resources can be devoted to countering the disease and promoting optimal long-term health for patients after joint injury.

  1. Molecular epidemiology of ascariasis

    DEFF Research Database (Denmark)

    Betson, Martha; Halstead, Fennella; Nejsum, Peter

      We are using molecular epidemiology techniques to study the population structure of Ascaris obtained from humans and pigs. Worms were obtained from human hosts on Zanzibar and in Uganda, Bangladesh, Guatemala and Nepal and Ascaris from pigs were collected from in Uganda, Tanzania, Denmark......, Guatemala and the Philippines. Genomic DNA was extracted from each worm and a 450 base pair fragment of the mitochondrial cytochrome oxidase gene subunit 1 (COI) was PCR amplified. The products were sequenced from both strands and sequences were manually edited. Fifty different Ascaris CO1 haplotypes were...

  2. Averaged currents induced by alpha particles in an InSb compound semiconductor detector

    International Nuclear Information System (INIS)

    Kanno, Ikuo; Hishiki, Shigeomi; Kogetsu, Yoshitaka; Nakamura, Tatsuya; Katagiri, Masaki

    2008-01-01

    Very fast pulses due to alpha particle incidence were observed by an undoped-type InSb Schottky detector. This InSb detector was operated without applying bias voltage and its depletion layer thickness was less than the range of alpha particles. The averaged current induced by alpha particles was analyzed as a function of operating temperature and was shown to be proportional to the Hall mobility of InSb. (author)

  3. Ultra-high carrier mobility InSb film by rapid thermal annealing on glass substrate

    Directory of Open Access Journals (Sweden)

    Charith Jayanada Koswaththage

    2016-11-01

    Full Text Available InSb films were deposited on both mica and glass substrates using thermal evaporation and subjected to FA or RTA. Crystallinity, composition and electrical properties were investigated. High Hall electron mobility as high as 25,000 cm2/(Vs was obtained with the capped InSb film by keeping the In:Sb ratio after RTA at 520°C for 30 sec or more without adopting epitaxial growth on glass.

  4. Electronic structure of FeTiSb using relativistic and scalar-relativistic approaches

    Energy Technology Data Exchange (ETDEWEB)

    Sahariya, Jagrati [Department of Physics, Manipal University Jaipur, Jaipur-303007, Rajasthan (India); Mund, H. S., E-mail: hmoond@gmail.com [Department of Physics, M. L. Sukhadia University, Udaipur-313001, Rajasthan (India)

    2016-05-06

    Electronic and magnetic properties of FeTiSb have been reported. The calculations are performed using spin polarized relativistic Korringa-Kohn-Rostoker scheme based on Green’s function method. Within SPR-KKR a fully relativistic and scalar-relativistic approaches have been used to investigate electronic structure of FeTiSb. Energy bands, total and partial density of states, atom specific magnetic moment along with total moment of FeTiSb alloys are presented.

  5. Antimony (SbIII) reduces growth, declines photosynthesis, and modifies leaf tissue anatomy in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Vaculík, Marek; Mrázová, Anna; Lux, Alexander

    2015-12-01

    The role of antimony (Sb)--a non-essential trace metalloid--in physiological processes running in crops is still poorly understood. Present paper describes the effect of Sb tartrate (SbIII) on growth, Sb uptake, photosynthesis, photosynthetic pigments, and leaf tissue organization in young sunflower plants grown in hydroponics. We found that growth of below- and aboveground part was reduced with increasing concentration of Sb in the medium. Although Sb was mostly taken up by sunflower roots and only small part (1-2%) was translocated to the shoots, decline in photosynthesis, transpiration, and decreased content of photosynthetic pigments were observed. This indicates that despite relatively low mobility of Sb in root-shoot system, Sb in shoot noticeably modifies physiological status and reduced plant growth. Additionally, leaf anatomical changes indicated that Sb reduced the size of intercellular spaces and made leaf tissue more compact.

  6. Worldwide Report, Epidemiology, No. 327

    National Research Council Canada - National Science Library

    1983-01-01

    Partial Contents: Epidemiology, Human Diseases, Health, Malaria, AIDS, Homosexual Male, Medical Administration, Rabies, Tuberculosis, Encephalitis Statistics, Gastroenteritie, Mystery Diseases, Children, Epidemics...

  7. Epidemiology, hunger and development

    Directory of Open Access Journals (Sweden)

    Paulo H. Battaglin Machado

    2008-06-01

    Full Text Available Understanding the relationship between epidemiology and food security implies in disclosing famine causes, the way it is distributed in the society and to which extent it affects the populations. Building up from that perspective, this paper attempts to understand the famine logic throughout the various transitions accomplished in the past decades: epidemiologic, demographic, risk, nutritional and development. The reflexes of the demographic transition that took place in Brazil in the XXth century are related to the population nutritional status standard changes, that is, they shifted from malnutrition high prevalence to a significant increase in obesity. However, the paradox of this situation is due to the fact that most risk factors that bring about diseases of the modern world come from the “excess”, while millions die around the globe because of “deprivation”. The food production alone does not ensure its equitable distribution among the various groups of the society. The access alone does not lead to quality. The choices are made individually, but life style options imply in a set of correlations that go from economy to culture. It means that this field has a collective basis and encompasses environment and development.

  8. Global epidemiology of sporotrichosis.

    Science.gov (United States)

    Chakrabarti, Arunaloke; Bonifaz, Alexandro; Gutierrez-Galhardo, Maria Clara; Mochizuki, Takashi; Li, Shanshan

    2015-01-01

    Sporotrichosis is an endemic mycosis caused by the dimorphic fungus Sporothrix schenckii sensu lato. It has gained importance in recent years due to its worldwide prevalence, recognition of multiple cryptic species within the originally described species, and its distinctive ecology, distribution, and epidemiology across the globe. In this review, we describe the current knowledge of the taxonomy, ecology, prevalence, molecular epidemiology, and outbreaks due to S. schenckii sensu lato. Despite its omnipresence in the environment, this fungus has remarkably diverse modes of infection and distribution patterns across the world. We have delved into the nuances of how sporotrichosis is intimately linked to different forms of human activities, habitats, lifestyles, and environmental and zoonotic interactions. The purpose of this review is to stimulate discussion about the peculiarities of this unique fungal pathogen and increase the awareness of clinicians and microbiologists, especially in regions of high endemicity, to its emergence and evolving presentations and to kindle further research into understanding the unorthodox mechanisms by which this fungus afflicts different human populations. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Clinical Epidemiology Of Stroke

    Directory of Open Access Journals (Sweden)

    Nagaraja D

    2005-01-01

    Full Text Available Stroke is a huge public health problem because of its high morbidity and disability. The epidemiology of stroke is of relevance to construct practical paradigms to tackle this major health issue in the community. Recent data have shown that about 72-86% of strokes are ischemic, 9-18% are due to hemorrhage (intracerebral of subarachnoid and the rest are undefined. The risk factors for stroke are multiple and combined. At present, stroke is no more considered as unavoidable and untreatable. It is an emergency and specialized units and teams improve outcome and lower costs. Death related to stroke is declining in many countries and in both sexes. This decrease in multifactorial. The detection and more effective treatment of hypertension may play an important factor, as well as the improved medical care and improvement in diagnostic procedures. While stroke incidence appears stable and stroke mortality is slowly declining, the absolute magnitude of stroke is likely to grow over the next 30 years. as the population ages, the absolute number of stroke victims and demands on healthcare and other support systems is likely to increase substantially in the future. Keeping this in perspective, this chapter shall focus on the epidemiology of stroke in the world and in Indian, in particular.

  10. Effects of reading goals on reading comprehension, reading rate, and allocation of working memory in children and adolescents with spina bifida meningomyelocele

    Science.gov (United States)

    ENGLISH, LIANNE; BARNES, MARCIA A.; FLETCHER, JACK M.; DENNIS, MAUREEN; RAGHUBAR, KIMBERLY P.

    2011-01-01

    Spina bifida meningomyelocele (SBM) is a neurodevelopmental disorder associated with intact word decoding and deficient text and discourse comprehension. This study investigated the ability to adjust reading in accordance with specified reading goals in 79 children and adolescents with SBM (9–19 years of age) and 39 controls (8–17 years of age). Both groups demonstrated slower reading times and enhanced comprehension when reading to study or to come up with a title than when reading for specific information or for entertainment. For both groups, verbal working memory contributed to comprehension performance in those reading conditions hypothesized to require more cognitive effort. Despite their sensitivity to the goals of reading, the group with SBM answered fewer comprehension questions correctly across all reading goal conditions. The results are discussed in relation to the hypothesized cognitive underpinnings of comprehension deficits in SBM and to current models of text comprehension. PMID:20338082

  11. Effects of reading goals on reading comprehension, reading rate, and allocation of working memory in children and adolescents with spina bifida meningomyelocele.

    Science.gov (United States)

    English, Lianne; Barnes, Marcia A; Fletcher, Jack M; Dennis, Maureen; Raghubar, Kimberly P

    2010-05-01

    Spina bifida meningomyelocele (SBM) is a neurodevelopmental disorder associated with intact word decoding and deficient text and discourse comprehension. This study investigated the ability to adjust reading in accordance with specified reading goals in 79 children and adolescents with SBM (9-19 years of age) and 39 controls (8-17 years of age). Both groups demonstrated slower reading times and enhanced comprehension when reading to study or to come up with a title than when reading for specific information or for entertainment. For both groups, verbal working memory contributed to comprehension performance in those reading conditions hypothesized to require more cognitive effort. Despite their sensitivity to the goals of reading, the group with SBM answered fewer comprehension questions correctly across all reading goal conditions. The results are discussed in relation to the hypothesized cognitive underpinnings of comprehension deficits in SBM and to current models of text comprehension.

  12. Synthesis and cathodoluminescence of Sb/P co-doped GaN nanowires

    International Nuclear Information System (INIS)

    Wang, Zaien; Liu, Baodan; Yuan, Fang; Hu, Tao; Zhang, Guifeng; Dierre, Benjamin; Hirosaki, Naoto; Sekiguchi, Takashi; Jiang, Xin

    2014-01-01

    Sb/P co-doped Gallium Nitride (GaN) nanowires were synthesized via a simple chemical vapor deposition (CVD) process by heating Ga 2 O 3 and Sb powders in NH 3 atmosphere. Scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS) measurements confirmed the as-synthesized products were Sb/P co-doped GaN nanowires with rough morphology and hexagonal wurtzite structure. Room temperature cathodoluminescence (CL) demonstrated that an obvious band shift of GaN nanowires can be observed due to Sb/P co-doping. Possible explanation for the growth and luminescence mechanism of Sb/P co-doped GaN nanowires was discussed. Highlight: • Sb/P co-doped GaN nanowires were synthesized through a well-designed multi-channel chemical vapor deposition (CVD) process. • Sb/P co-doping leads to the crystallinity deterioration of GaN nanowires. • Sb/P co-doping caused the red-shift of GaN nanowires band-gap in UV range. • Compared with Sb doping, P atoms are more easy to incorporate into the GaN lattice

  13. Self-organized formation of GaSb/GaAs quantum rings.

    Science.gov (United States)

    Timm, R; Eisele, H; Lenz, A; Ivanova, L; Balakrishnan, G; Huffaker, D L; Dähne, M

    2008-12-19

    Ring-shaped GaSb/GaAs quantum dots, grown by molecular beam epitaxy, were studied using cross-sectional scanning tunneling microscopy. These quantum rings have an outer shape of a truncated pyramid with baselengths around 15 nm and heights of about 2 nm but are characterized by a clear central opening extending over about 40% of the outer baselength. They form spontaneously during the growth and subsequent continuous capping of GaSb/GaAs quantum dots due to the large strain and substantial As-for-Sb exchange reactions leading to strong Sb segregation.

  14. Three dimensional atom probe imaging of GaAsSb quantum rings.

    Science.gov (United States)

    Beltrán, A M; Marquis, E A; Taboada, A G; Ripalda, J M; García, J M; Molina, S I

    2011-07-01

    Unambiguous evidence of ring-shaped self-assembled GaSb nanostructures grown by molecular beam epitaxy is presented on the basis of atom-probe tomography reconstructions and dark field transmission electron microscopy imaging. The GaAs capping process causes a strong segregation of Sb out of the center of GaSb quantum dots, leading to the self-assembled GaAs(x)Sb(1-x) quantum rings of 20-30 nm in diameter with x ∼ 0.33. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. N-doped Sb2Te phase change materials for higher data retention

    International Nuclear Information System (INIS)

    Zhu Min; Wu Liangcai; Rao Feng; Song Zhitang; Li Xuelai; Peng Cheng; Zhou Xilin; Ren Kun; Yao Dongning; Feng Songlin

    2011-01-01

    Highlights: → Crystallization temperatures of the N-doped Sb 2 Te films increase remarkably. → The E a of N-doped Sb 2 Te films increase first, and then decrease. → The best 10-years lifetime at temperature up to 141 deg. C is found in Sb 2 TeN1 films. → The power consumption of PCRAM test cell based on Sb 2 TeN1 film is low. - Abstract: Crystallization temperatures of the Sb 2 Te films increase remarkably from 139.4 deg. C to 223.0 deg. C as the N 2 flow rates increasing from 0 sccm to 1.5 sccm. Electrical conduction activation energies for amorphous and crystalline states increase by doping nitrogen. A small amount of nitrogen atoms can locate at interstitial sites in the hexagonal structure, generating a strain field, and improving the thermal stability of amorphous state. The best 10-years lifetime at temperature up to 141 deg. C is found in Sb 2 TeN 1 films. Doping excessively high nitrogen in Sb 2 Te film will form nitride and make Te separate out. As a result, the activation energy for crystallization decreases instead, accompanying with the deterioration of thermal stability. The power consumption of PCRAM test cell based on Sb 2 TeN 1 film is ten times lower than that of PCRAM device using Ge 2 Sb 2 Te 5 films.

  16. Electrochemical performance of Sn-Sb-Cu film anodes prepared by layer-by-layer electrodeposition

    International Nuclear Information System (INIS)

    Jiang Qianlei; Xue Ruisheng; Jia Mengqiu

    2012-01-01

    A novel layer-by-layer electrodeposition and heat-treatment approach was attempted to obtain Sn-Sb-Cu film anode for lithium ion batteries. The preparation of Sn-Sb-Cu anodes started with galvanostatic electrochemically depositing antimony and tin sequentially on the substrate of copper foil collector. Sn-Sb and Cu-Sb alloys were formed when heated. The SEM analysis showed that the crystalline grains become bigger and the surface of the Sn-Sb-Cu anode becomes more denser after annealing. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed the antimony, tin and copper were alloyed to form SnSb and Cu 2 Sb after heat treatment. The X-ray photoelectron spectroscopy (XPS) analysis showed the surface of the Sn-Sb-Cu electrode was covered by a thin oxide layer. Electrochemical measurements showed that the annealed Sn-Sb-Cu anode has high reversible capacity and good capacity retention. It exhibited a reversible capacity of about 962 mAh/g in the initial cycle, which still remained 715 mAh/g after 30 cycles.

  17. The Quantum Chemistry Calculation and Thermoelectrics of Bi-Sb-Te Series

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The density function theory and discrete variation method(DFT-DVM) was used to study correlation between composition, structure, chemical bond,and property of thermoelectrics of Bi-Sb-Te series.8 models of Bi20-xSbxTe32(x=0,2,6,8,12,14,18 and 20) were calculated.The results show that there is less difference in the ionic bonds between Te(Ⅰ)-Bi(Sb) and Te(Ⅱ)-Bi(Sb), but the covalent bond of Te(Ⅰ)-Bi(Sb) is stronger than that of Te(Ⅱ)-Bi(Sb).The interaction between Te(Ⅰ) and Te(Ⅰ) in different layers is the weakest and the interaction should be Van Der Waals power.The charge of Sb is lower than that of Bi,and the ionic bond of Te-Sb is weaker than that of Te-Bi.The covalent bond of Te-Sb is also weaker than that of Te-Bi.Therefore,the thermoelectric property may be improved by adjusting the electrical conductivity and thermal conductivity through changing the composition in the compounds of Bi-Sb-Te. The calculated results are consistent with the experiments.

  18. 0+ analogue state in 118Sb from 117Sn(p,nγ) reaction

    International Nuclear Information System (INIS)

    Pal, J.; Dey, C.C.; Bose, S.; Sinha, B.K.; Chatterjee, M.B.; Mahapatra, D.P.

    1996-01-01

    The analogue of the 0 + ground state in 118 Sn has been observed in the compound nucleus 118 Sb through 117 Sn(p,nγ) 117 Sb reaction. The neutron decays of this analogue resonance have been studied from the deexciting γ-rays of the residual nucleus 117 Sb. From off resonance excitation functions, spin assignments have been made to states in 117 Sb, on the basis of Hauser-Feshbach formalism. The resonance parameters of the isobaric analogue resonance have been determined, including the total, proton and neutron decay widths. (orig.)

  19. Atomistic explanation of brittle failure of thermoelectric skutterudite CoSb3

    International Nuclear Information System (INIS)

    Li, Guodong; An, Qi; Goddard, William A.; Hanus, Riley; Zhai, Pengcheng; Zhang, Qingjie; Snyder, G. Jeffrey

    2016-01-01

    CoSb 3 based skutterudite thermoelectric material has superior thermoelectric properties, but the low fracture toughness prevents its widespread commercial application. To determine the origin of its brittle failure, we examined the response of shear deformation in CoSb 3 along the most plausible slip system (010)/<100>, using large-scale molecular dynamics simulations. We find that the brittle failure of CoSb 3 arises from the formation of shear bands due to the destruction of Sb4-rings and the slippage of Co-octahedraes. This leads to the breakage of Co-octahedraes and cavitation, resulting in the crack opening and mechanical failure.

  20. Multilayer SnSb4-SbSe Thin Films for Phase Change Materials Possessing Ultrafast Phase Change Speed and Enhanced Stability.

    Science.gov (United States)

    Liu, Ruirui; Zhou, Xiao; Zhai, Jiwei; Song, Jun; Wu, Pengzhi; Lai, Tianshu; Song, Sannian; Song, Zhitang

    2017-08-16

    A multilayer thin film, comprising two different phase change material (PCM) components alternatively deposited, provides an effective means to tune and leverage good properties of its components, promising a new route toward high-performance PCMs. The present study systematically investigated the SnSb 4 -SbSe multilayer thin film as a potential PCM, combining experiments and first-principles calculations, and demonstrated that these multilayer thin films exhibit good electrical resistivity, robust thermal stability, and superior phase change speed. In particular, the potential operating temperature for 10 years is shown to be 122.0 °C and the phase change speed reaches 5 ns in the device test. The good thermal stability of the multilayer thin film is shown to come from the formation of the Sb 2 Se 3 phase, whereas the fast phase change speed can be attributed to the formation of vacancies and a SbSe metastable phase. It is also demonstrated that the SbSe metastable phase contributes to further enhancing the electrical resistivity of the crystalline state and the thermal stability of the amorphous state, being vital to determining the properties of the multilayer SnSb 4 -SbSe thin film.

  1. Sb-Te Phase-change Materials under Nanoscale Confinement

    Science.gov (United States)

    Ihalawela, Chandrasiri A.

    Size, speed and efficiency are the major challenges of next generation nonvolatile memory (NVM), and phase-change memory (PCM) has captured a great attention due to its promising features. The key for PCM is rapid and reversible switching between amorphous and crystalline phases with optical or electrical excitation. The structural transition is associated with significant contrast in material properties which can be utilized in optical (CD, DVD, BD) and electronic (PCRAM) memory applications. Importantly, both the functionality and the success of PCM technology significantly depend on the core material and its properties. So investigating PC materials is crucial for the development of PCM technology to realized enhanced solutions. In regards to PC materials, Sb-Te binary plays a significant role as a basis to the well-known Ge-Sb-Te system. Unlike the conventional deposition methods (sputtering, evaporation), electrochemical deposition method is used due to its multiple advantages, such as conformality, via filling capability, etc. First, the controllable synthesis of Sb-Te thin films was studied for a wide range of compositions using this novel deposition method. Secondly, the solid electrolytic nature of stoichiometric Sb2Te3 was studied with respect to precious metals. With the understanding of 2D thin film synthesis, Sb-Te 1D nanowires (18 - 220 nm) were synthesized using templated electrodeposition, where nanoporous anodic aluminum oxide (AAO) was used as a template for the growth of nanowires. In order to gain the controllability over the deposition in high aspect ratio structures, growth mechanisms of both the thin films and nanowires were investigated. Systematic understanding gained thorough previous studies helped to formulate the ultimate goal of this dissertation. In this dissertation, the main objective is to understand the size effect of PC materials on their phase transition properties. The reduction of effective memory cell size in conjunction with

  2. Neuromuscular training based on whole body vibration in children with spina bifida: a retrospective analysis of a new physiotherapy treatment program.

    Science.gov (United States)

    Stark, C; Hoyer-Kuhn, H-K; Semler, O; Hoebing, L; Duran, I; Cremer, R; Schoenau, E

    2015-02-01

    Spina bifida is the most common congenital cause of spinal cord lesions resulting in paralysis and secondary conditions like osteoporosis due to immobilization. Physiotherapy is performed for optimizing muscle function and prevention of secondary conditions. Therefore, training of the musculoskeletal system is one of the major aims in the rehabilitation of children with spinal cord lesions. The neuromuscular physiotherapy treatment program Auf die Beine combines 6 months of home-based whole body vibration (WBV) with interval blocks at the rehabilitation center: 13 days of intensive therapy at the beginning and 6 days after 3 months. Measurements are taken at the beginning (M0), after 6 months of training (M6), and after a 6-month follow-up period (M12). Gait parameters are assessed by ground reaction force and motor function by the Gross Motor Function Measurement (GMFM-66). Sixty children (mean age 8.71 ± 4.7 years) who participated in the program until February 2014 were retrospectively analyzed. Walking velocity improved significantly by 0.11 m/s (p = 0.0026) and mobility (GMFM-66) by 2.54 points (p = 0.001) after the training. All changes at follow-up were not significant, but significant changes were observed after the training period. Decreased contractures were observed with increased muscle function. Significant improvements in motor function were observed after the active training period of the new neuromuscular training concept. This first analysis of the new neuromuscular rehabilitation concept Auf die Beine showed encouraging results for a safe and efficient physiotherapy treatment program which increases motor function in children with spina bifida.

  3. Formate supplementation enhances folate-dependent nucleotide biosynthesis and prevents spina bifida in a mouse model of folic acid-resistant neural tube defects.

    Science.gov (United States)

    Sudiwala, Sonia; De Castro, Sandra C P; Leung, Kit-Yi; Brosnan, John T; Brosnan, Margaret E; Mills, Kevin; Copp, Andrew J; Greene, Nicholas D E

    2016-07-01

    The curly tail mouse provides a model for neural tube defects (spina bifida and exencephaly) that are resistant to prevention by folic acid. The major ct gene, responsible for spina bifida, corresponds to a hypomorphic allele of grainyhead-like 3 (Grhl3) but the frequency of NTDs is strongly influenced by modifiers in the genetic background. Moreover, exencephaly in the curly tail strain is not prevented by reinstatement of Grhl3 expression. In the current study we found that expression of Mthfd1L, encoding a key component of mitochondrial folate one-carbon metabolism (FOCM), is significantly reduced in ct/ct embryos compared to a partially congenic wild-type strain. This expression change is not attributable to regulation by Grhl3 or the genetic background at the Mthfd1L locus. Mitochondrial FOCM provides one-carbon units as formate for FOCM reactions in the cytosol. We found that maternal supplementation with formate prevented NTDs in curly tail embryos and also resulted in increased litter size. Analysis of the folate profile of neurulation-stage embryos showed that formate supplementation resulted in an increased proportion of formyl-THF and THF but a reduction in proportion of 5-methyl THF. In contrast, THF decreased and 5-methyl THF was relatively more abundant in the liver of supplemented dams than in controls. In embryos cultured through the period of spinal neurulation, incorporation of labelled thymidine and adenine into genomic DNA was suppressed by supplemental formate, suggesting that de novo folate-dependent biosynthesis of nucleotides (thymidylate and purines) was enhanced. We hypothesise that reduced Mthfd1L expression may contribute to susceptibility to NTDs in the curly tail strain and that formate acts as a one-carbon donor to prevent NTDs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  4. A new experimental phase diagram investigation of Cu-Sb.

    Science.gov (United States)

    Fürtauer, Siegfried; Flandorfer, Hans

    The binary system Cu-Sb is a constituent system that is studied in investigations of technically important ternary and quaternary alloy systems (e.g., casting alloys and lead-free solders). Although this binary system has been thoroughly investigated over the last century, there are still some uncertainties regarding its high-temperature phases. Thus, parts of its phase diagram have been drawn with dashed lines in reviews published in the literature. The aim of this work was to resolve these uncertainties in the current phase diagram of Cu-Sb by performing XRD, SEM-EDX, EPMA, and DTA. The results from thermal analysis agreed well with those given in the literature, although some modifications due to the invariant reaction temperatures were necessary. In particular, reactions located on the Cu-rich side of the nonquenchable high-temperature β phase (BiF 3 -type) left considerable scope for interpretation. Generally, the structural descriptions of the various binary phases given in the literature were verified. The range of homogeneity of the ε phase (Cu 3 Ti type) was found to be higher on the Sb-rich side. Most of the reaction temperatures were verified, but a few had to be revised, such as the eutectoid reaction [Formula: see text] at 440 °C (found to occur at 427 °C in this work) and the eutectoid reaction [Formula: see text] at 400 °C (found to occur at 440 °C in this work). Further phase transformations that had previously only been estimated were confirmed, and their characteristic temperatures were determined.

  5. Radiation-induced defects in As-Sb-S glass

    International Nuclear Information System (INIS)

    Balitska, V; Shpotyuk, Ya; Filipecki, J; Shpotyuk, O

    2010-01-01

    Defect-related instability was studied in γ-irradiated (As 2 S 3 ) 1-x (Sb 2 S 3 ) x glasses (x = 0, 0.1, 0.2 and 0.3) using positron annihilation lifetime spectroscopy treated within high-measurement statistics. The observed decrease in average positron lifetime in the studied glasses is explained as a renovation of destroyed covalent chemical bonds after irradiation. This process is governed by monomolecular relaxation kinetics, being described in the framework of universal configuration-coordinate model.

  6. Radiation-induced defects in As-Sb-S glass

    Energy Technology Data Exchange (ETDEWEB)

    Balitska, V; Shpotyuk, Ya; Filipecki, J; Shpotyuk, O, E-mail: shpotyuk@novas.lviv.ua

    2010-11-15

    Defect-related instability was studied in {gamma}-irradiated (As{sub 2}S{sub 3}){sub 1-x}(Sb{sub 2}S{sub 3}){sub x} glasses (x = 0, 0.1, 0.2 and 0.3) using positron annihilation lifetime spectroscopy treated within high-measurement statistics. The observed decrease in average positron lifetime in the studied glasses is explained as a renovation of destroyed covalent chemical bonds after irradiation. This process is governed by monomolecular relaxation kinetics, being described in the framework of universal configuration-coordinate model.

  7. Recombination coefficients in extrinsic n-InSb

    International Nuclear Information System (INIS)

    Schneider, W.; Groh, H.; Huebner, K.

    1976-01-01

    The bulk recombination coefficients for linear recombination via recombination centers as well as for direct recombination have been determined measuring the conductivity decay after two-photon absorption with a CO 2 laser. The Suhl effect was applied to measure the surface recombination velocity. The corresponding literature is discussed and compared with our results. We conclude that two different kinds of recombination centers are possible in n-InSb, with energy levels (0.1-0.12)eV above the valence band, or (0.14-0.2)eV respectively. (orig.) [de

  8. Defect analysis of NiMnSb epitaxial layers

    Energy Technology Data Exchange (ETDEWEB)

    Nowicki, L. [Andrzej SoItan Institute for Nuclear Studies, ul. Hoza 69, 00-681 Warsaw (Poland)]. E-mail: lech.nowicki@fuw.edu.pl; Turos, A. [Andrzej SoItan Institute for Nuclear Studies, ul. Hoza 69, 00-681 Warsaw (Poland); Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Stonert, A. [Andrzej SoItan Institute for Nuclear Studies, ul. Hoza 69, 00-681 Warsaw (Poland); Garrido, F. [Centre de Spectrometrie Nucleaire et Spectrometrie de Masse, CNRS-IN2P3-Universite Paris-Sud, 91405 Orsay (France); Molenkamp, L.W. [Department of Physics, University Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Bach, P. [Department of Physics, University Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Schmidt, G. [Department of Physics, University Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Karczewski, G. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Muecklich, A. [Forschungszentrum Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, POB 510119, 01314 Dresden (Germany)

    2005-10-15

    NiMnSb layers grown on InP substrates with InGaAs buffer were studied by the backscattering/channeling spectrometry (RBS/C) with He beams. The nature of predominant defects observed in the layers was studied by determination of incident-energy dependence of the relative channeling yield. The defects are described as a combination of large amount of interstitial atoms and of stacking faults or grain boundaries. The presence of grains was confirmed by transmission electron microscopy.

  9. Transmutation doping and lattice defects in degenerate InSb

    International Nuclear Information System (INIS)

    Gerstenberg, H.; Glaeser, W.

    1990-01-01

    n-type InSb single crystals were irradiated with thermal neutrons below T = 6 K. The Shubnikov-de Haas effect and the resistivity ρ(T = 4.6 K) were measured as a function of the neutron dose and the holding temperature of a subsequent annealing program. The results are discussed in terms of the transport scattering rate and the lifetime of the Landau-levels. They have to be interpreted by means of n-doping due to nuclear reactions and irradiation induced negatively charged defects. Almost complete annealing of the transport parameters can be achieved by heating the samples to T A = 400 K. (author)

  10. Simultaneous removal of Cd(II) and Sb(V) by Fe–Mn binary oxide: Positive effects of Cd(II) on Sb(V) adsorption

    International Nuclear Information System (INIS)

    Liu, Ruiping; Liu, Feng; Hu, Chengzhi; He, Zan; Liu, Huijuan; Qu, Jiuhui

    2015-01-01

    Highlights: • Fe–Mn binary oxide achieves the simultaneous removal of Cd(II) and Sb(V). • Cd(II) at above 0.25 mmol/L improves Sb(V) adsorption onto FMBO. • Cd(II) improves more significant Sb(V) adsorption than Ca"2"+ and Mn"2"+. • Sb(V) adsorption decreases whereas Cd(II) adsorption increases with elevated pH. • The increased ζ-potential and Cd(II)–Sb(V) precipitation favors Sb(V) adsorption. - Abstract: The coexistence of cadmium ion (Cd(II)) and antimonate (Sb(V)) creates the need for their simultaneous removal. This study aims to investigate the effects of positively-charged Cd(II) on the removal of negative Sb(V) ions by Fe–Mn binary oxide (FMBO) and associated mechanisms. The maximum Sb(V) adsorption density (Q_m_a_x_,_S_b_(_V_)) increased from 1.02 to 1.32 and 2.01 mmol/g in the presence of Cd(II) at 0.25 and 0.50 mmol/L. Cd"2"+ exhibited a more significant positive effect than both calcium ion (Ca"2"+) and manganese ion (Mn"2"+). Cd"2"+ showed higher affinity towards FMBO and increased its ζ-potential more significantly compared to Ca"2"+ and Mn"2"+. The simultaneous adsorption of Sb(V) and Cd(II) onto FMBO can be achieved over a wide initial pH (pH_i) range from 2 to 9, and Q_S_b_(_V_) decreases whereas Q_C_d_(_I_I_) increases with elevated pH_i. Their combined values, as expressed by Q_S_b_(_V_)_+_C_d_(_I_I_), amount to about 2 mmol/g and vary slightly in the pH_i range 4–9. FTIR and XPS spectra indicate the significant synergistic effect of Cd(II) on Sb(V) adsorption onto FMBO, and that little chemical valence transformation occurs. These results may be valuable for the treatment of wastewater with coexisting heavy metals such as Cd(II) and Sb(V).

  11. Characterization of Cu3SbS3 thin films grown by thermally diffusing Cu2S and Sb2S3 layers

    OpenAIRE

    Hussain, Arshad; Ahmed, Rashid; Ali, N.; Shaari, A.; Luo, Jing-Ting; Fu, Yong Qing

    2017-01-01

    Copper antimony sulphide (Cu3SbS3) with a p-type conductivity and optical band gaps in the range of 1.38 to 1.84 eV is considered to be a promising solar harvesting material with non-toxic and economical elements. In this study, we reported the fabrication of Cu3SbS3 thin films using successive thermal evaporation of Cu2S and Sb2S3 layers followed by annealing in an argon atmosphere at a temperature range of 300-375°C. The structural and optical properties of the as-deposited and annealed fil...

  12. First-principles study of electronic structure of CuSbS{sub 2} and CuSbSe{sub 2} photovoltaic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, T., E-mail: tmaeda@ad.ryukoku.ac.jp; Wada, T.

    2015-05-01

    We studied the features of CuSbS{sub 2} (CAS) and CuSbSe{sub 2} (CASe), two proposed photovoltaic compounds, and clarified their electronic structures by first-principles calculations and compared them to the chalcopyrite-type CuInSe{sub 2} results. For both CAS and CASe, the calculated enthalpies of formation of the chalcostibite phases were considerably lower than those of the chalcopyrite phases. Therefore, we considered that the chalcostibite phase is more stable for CAS and CASe. In their band structure calculated with the HSE06 hybrid functional, the valence band maxima of CAS and CASe were located at the Γ-point, and the conduction band minima were located at the R-point. Their second lowest conduction band was located at the Γ-point, whose energy level nearly equaled the R-point. For CAS (CASe), the partial density of the states shows the character of the Cu 3d and S 3p (Se 4p) orbitals at the top of the valence bands and the Sb 5p and S 3p (Se 4p) orbitals at the bottom of the conduction bands. The conduction bands of CAS and CASe have a p-orbital character (Sb 5p) that differs from the s-orbital character (In 5s) of CuInSe{sub 2}. It is for the reason that CAS and CASe do not have a chalcopyrite structure but a chalcostibite-type structure. The calculated absorption coefficient of CuSbS{sub 2} (10{sup 4}-10{sup 5} cm{sup −1}) is comparable to that of CuInSe{sub 2}. - Highlights: • We studied the features of CuSbS{sub 2} and CuSbSe{sub 2}, newly proposed photovoltaic compounds. • Chalcostibite phase is more stable in CuSbS{sub 2} and CuSbSe{sub 2}. • Band structures of CuSbS{sub 2} and CuSbS{sub 2} were calculated with HSE06 hybrid functional. • Absorption coefficient of chalcostibite-type CuSbS{sub 2} is comparable to that of CuInSe{sub 2}.

  13. The Influence of Growth Temperature on Sb Incorporation in InAsSb, and the Temperature-dependent Impact of Bi Surfactants

    Science.gov (United States)

    2014-01-01

    temperature was set to give a beam equivalent pressure ( BEP ) of 4.8x10-7 Torr, as measured in this configuration. 10 4 We have shown in prior...to the value needed to grow lattice matched InAsSb on GaSb without using Bi surfactant at 415 C. The In growth rate was 1 m/hr. The Sb BEP was...1.2x10-7 Torr and the As BEP was 5.71x10-7 Torr. The absolute flux of all the constituents and the V/III ratios were kept constant for both layers of

  14. Optical and electrical properties of Te doped AlGaAsSb/AlAsSb Bragg mirrors on InP

    OpenAIRE

    Toginho Filho, D. O.; Dias, I. F. L.; Duarte, J. L.; Laureto, E.

    2006-01-01

    We present a comparative study carried out on the optical and electrical characteristics of undoped and Te doped AlGaAsSb/AlAsSb Bragg mirrors with 6.5 pairs of layers and bulk undoped and Te doped AlGaAsSb epilayers alloys lattice matched on InP, grown by molecular beam epitaxy, using SIMS, photoluminescence, reflectivity and IxV techniques. The temperature dependence of PL transitions observed in the Bragg mirrors are similar to that observed in bulk samples and associated with the donor an...

  15. Microstructure evolution in pulsed laser deposited epitaxial Ge-Sb-Te chalcogenide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Ulrich; Lotnyk, Andriy, E-mail: andriy.lotnyk@iom-leipzig.de; Thelander, Erik; Rauschenbach, Bernd

    2016-08-15

    The thin film deposition and structure of highly oriented telluride compounds is of particular interest for phase-change applications in next-generation non-volatile memory such as heterostructure designs, as well as for the investigation of novel optical, thermoelectric and ferroelectric properties in layered telluride compounds. In this work, epitaxial Ge-Sb-Te thin films were successfully produced by pulsed laser deposition on silicon with and without amorphous SiO{sub x} interlayer at elevated process temperatures from a Ge{sub 2}Sb{sub 2}Te{sub 5} target. Aberration-corrected high-resolution scanning transmission electron microscopy (STEM) imaging reveals a distinct interface configuration of the trigonal phase connected by a quasi van der Waals gap (vacancy) to the Sb/Te-passivated single crystalline Si substrate, yet also an intermediate textured growth regime in which the substrate symmetry is only weakly coupled to the thin film orientation, as well as strong deviation of composition at high deposition temperatures. Textured growth of Ge-Sb-Te thin film was also observed on SiO{sub x}/Si substrate with no evidence of an intermediate Sb/Te surface layer on top of an SiO{sub x} layer. In addition, particular defect structures formed by local reorganization of the stacking sequence across the vacancy gap are observed and appear to be intrinsic to these van der Waals-layered compounds. Theoretical image simulations of preferred stacking sequences can be matched to individual building blocks in the Ge-Sb-Te grain. - Highlights: • Atomic-resolution Cs-corrected STEM imaging of PLD deposited Ge-Sb-Te thin films. • Changing of overall composition with increasing deposition temperature. • Direct imaging of surface passivation Sb/Te layer at the Ge-Sb-Te/Si(111) interface. • The Sb/Te passivation layer is not a prerequisite for highly oriented growth of Ge-Sb-Te thin films.

  16. Peculiarities of thermoelectric half-Heusler phase formation in Zr–Co–Sb ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Romaka, V.V., E-mail: romakav@lp.edu.ua [Department of Applied Material Science and Materials Engineering, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Institut für Physikalische Chemie, Universität Wien, Währingerstr. 42, A-1090 Wien (Austria); Romaka, L. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Rogl, P. [Institut für Physikalische Chemie, Universität Wien, Währingerstr. 42, A-1090 Wien (Austria); Stadnyk, Yu. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Melnychenko, N. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Army Academy named after Hetman Petro Sahaydachnyi, Gvardijska Str. 32, 79012 Lviv (Ukraine); Korzh, R.; Duriagina, Z. [Department of Applied Material Science and Materials Engineering, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Horyn, A. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine)

    2014-02-05

    Highlights: • Phase relations for the Zr–Co–Sb system at 500 °C. • Homogeneity region for half-Heusler phase. • The distribution of DOS for Zr{sub 1+x}Co{sub 1−x}Sb predicts transition from semiconductor (x = 0) to metallic (x = 0.13) like behavior. • The existence of the solid solution Zr{sub 5}Co{sub x}Sb{sub 3+y} (x = 0.0–1.0, y = 0.0–1.0). -- Abstract: The phase equilibria in the Zr–Co–Sb ternary system were studied at 873 K by means of X-ray and metallographic analyses in the whole concentration range. The interaction between the elements results the formation of four ternary compounds at investigated temperature: ZrCoSb (MgAgAs-type), Zr{sub 6}CoSb{sub 2} (K{sub 2}UF{sub 6}-type), Zr{sub 5}CoSb{sub 3} (Hf{sub 5}CuSn{sub 3}-type) and Zr{sub 5}Co{sub 0.5}Sb{sub 2.5} (W{sub 5}Si{sub 3}-type). The limited composition Zr{sub 5}CoSb{sub 3} of the solid solution based on the Zr{sub 5}Sb{sub 3−4} binaries is considered as compound with Hf{sub 5}CuSn{sub 3} structure type. The influence of the disordering and defects in the crystal structure of ZrCoSb on the physical properties was analyzed. The performed electronic structure calculations are in good agreement with electrical and magnetic studies.

  17. Cancer Epidemiology Data Repository (CEDR)

    Science.gov (United States)

    In an effort to broaden access and facilitate efficient data sharing, the Epidemiology and Genomics Research Program (EGRP) has created the Cancer Epidemiology Data Repository (CEDR), a centralized, controlled-access database, where Investigators can deposit individual-level de-identified observational cancer datasets.

  18. CEDR: Comprehensive Epidemiologic Data Resource

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    The Department of Energy (DOE) and its predecessor agencies have a long history of epidemiologic research programs. The main focus of these programs has been the Health and Mortality Study of the DOE work force. This epidemiologic study began in 1964 with a feasibility study of workers at the Hanford facility. Studies of other populations exposed to radiation have also been supported, including the classic epidemiologic study of radium dial painters and studies of atomic bomb survivors. From a scientific perspective, these epidemiologic research program have been productive, highly credible, and formed the bases for many radiological protection standards. Recently, there has been concern that, although research results were available, the data on which these results were based were not easily obtained by interested investigators outside DOE. Therefore, as part of an effort to integrate and broaden access to its epidemiologic information, the DOE has developed the Comprehensive Epidemiologic Data Resource (CEDR) Program. Included in this effort is the development of a computer information system for accessing the collection of CEDR data and its related descriptive information. The epidemiologic data currently available through the CEDAR Program consist of analytic data sets, working data sets, and their associated documentation files. In general, data sets are the result of epidemiologic studies that have been conducted on various groups of workers at different DOE facilities during the past 30 years.

  19. Epidemiology of fibromyalgia.

    Science.gov (United States)

    Neumann, Lily; Buskila, Dan

    2003-10-01

    Chronic widespread pain, the cardinal symptom of fibromyalgia (FM), is common in the general population, with comparable prevalence rates of 7.3% to 12.9% across different countries. The prevalence of FM in the general population was reported to range from 0.5% to 5% and up to 15.7% in the clinic. The common association of FM with other rheumatic disorders, chronic viral infections, and systemic illnesses has been well documented in several studies. Up to 65% of patients with systemic lupus erythematosus meet the criteria for FM. FM is considered a member of the family of functional somatic syndromes. These syndromes are very common and share a similar phenomenology, epidemiologic characteristics, high rates of occurrence, a common pathogenesis, and similar management strategies. A high prevalence of FM was demonstrated among relatives of patients with FM and it may be attributed to genetic and environmental factors.

  20. [Epidemiology of osteoporosis].

    Science.gov (United States)

    Grazio, Simeon

    2006-01-01

    Osteoporosis represents a major and increasing public health problem with the aging of population. Major clinical consequences and economic burden of the disease are fractures. Many risk factors are associated with the fractures including low bone mass, hormonal disorders, personal and family history of fractures, low body weight, use of certain drugs (e.g. glucocorticoids), cigarette smoking, elevated intake of alchohol, low physical activity, insufficient level of vitamin D and low intake of calcium. This epidemiological review describes frequency, importance of risk factors and impact of osteoporosis and osteoporotic fractures. Objective measures of bone mineral density along with clinical assessment of risk factors can help identify patients who will benefit from prevention and intervention efforts and eventually reduce the morbidity and mortality associated with osteoporosis-related fractures.

  1. Temporal network epidemiology

    CERN Document Server

    Holme, Petter

    2017-01-01

    This book covers recent developments in epidemic process models and related data on temporally varying networks. It is widely recognized that contact networks are indispensable for describing, understanding, and intervening to stop the spread of infectious diseases in human and animal populations; “network epidemiology” is an umbrella term to describe this research field. More recently, contact networks have been recognized as being highly dynamic. This observation, also supported by an increasing amount of new data, has led to research on temporal networks, a rapidly growing area. Changes in network structure are often informed by epidemic (or other) dynamics, in which case they are referred to as adaptive networks. This volume gathers contributions by prominent authors working in temporal and adaptive network epidemiology, a field essential to understanding infectious diseases in real society.

  2. [Ethics and epidemiology].

    Science.gov (United States)

    Barata, Rita Barradas

    2005-01-01

    Human actions take place at the confluence of circumstances that require us to discern the proper way to act. Ethics falls within the terrain of practical knowledge, of knowledge about what is contingent. It belongs to the domain of moral judgments or value judgments. The counterpart of disenchantment with our contemporary world lies in an effort to re-establish an interest in ethics. There are basically three orders of relations between public health and human rights: the quest for balance between the collective good and individual rights; methods and techniques for identifying human rights violations and assessing their negative impact; and the tie between protecting individual rights and promoting health. The relationship between ethics and epidemiology goes beyond the ethical aspects involving research on human beings to encompass political commitments, practices within health services, and the production of knowledge.

  3. The Epidemiology of Sarcoma

    Directory of Open Access Journals (Sweden)

    Burningham Zachary

    2012-10-01

    Full Text Available Abstract Sarcomas account for over 20% of all pediatric solid malignant cancers and less than 1% of all adult solid malignant cancers. The vast majority of diagnosed sarcomas will be soft tissue sarcomas, while malignant bone tumors make up just over 10% of sarcomas. The risks for sarcoma are not well-understood. We evaluated the existing literature on the epidemiology and etiology of sarcoma. Risks for sarcoma development can be divided into environmental exposures, genetic susceptibility, and an interaction between the two. HIV-positive individuals are at an increased risk for Kaposi’s sarcoma, even though HHV8 is the causative virus. Radiation exposure from radiotherapy has been strongly associated with secondary sarcoma development in certain cancer patients. In fact, the risk of malignant bone tumors increases as the cumulative dose of radiation to the bone increases (p for trend

  4. Epidemiology of Lyme Disease

    Directory of Open Access Journals (Sweden)

    Dennis J White

    1991-01-01

    Full Text Available Investigation of the epidemiology of Lyme disease depends upon information generated from several sources. Human disease surveillance can be conducted by both passive and active means involving physicians, public health agencies and laboratories. Passive and active tick surveillance programs can document the extent of tick-borne activity, identify the geographic range of potential vector species, and determine the relative risk of exposure to Lyme disease in specific areas. Standardized laboratory services can play an important role in providing data. Epidemiologists can gain a better understanding of Lyme disease through the collection of data from such programs. The interpretation of data and provision of information to the medical and general communities are important functions of public health agencies.

  5. Point defect states in Sb-doped germanium

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Neil S., E-mail: neilp@mit.edu; Monmeyran, Corentin, E-mail: comonmey@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States); Agarwal, Anuradha [Microphotonics Center, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States); Kimerling, Lionel C. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States); Microphotonics Center, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States)

    2015-10-21

    Defect states in n-type Sb-doped germanium were investigated by deep-level transient spectroscopy. Cobalt-60 gamma rays were used to generate isolated vacancies and interstitials which diffuse and react with impurities in the material to form four defect states (E{sub 37}, E{sub 30}, E{sub 22}, and E{sub 21}) in the upper half of the bandgap. Irradiations at 77 K and 300 K as well as isothermal anneals were performed to characterize the relationships between the four observable defects. E{sub 37} is assigned to the Sb donor-vacancy associate (E-center) and is the only vacancy containing defect giving an estimate of 2 × 10{sup 11 }cm{sup −3} Mrad{sup −1} for the uncorrelated vacancy-interstitial pair introduction rate. The remaining three defect states are interstitial associates and transform among one another. Conversion ratios between E{sub 22}, E{sub 21}, and E{sub 30} indicate that E{sub 22} likely contains two interstitials.

  6. SB LOCA analyses for Krsko Full Scope Simulator verification

    International Nuclear Information System (INIS)

    Prosek, A.; Parzer, I.; Mavko, B.

    2000-01-01

    Nuclear power plant simulators are intended to be used for training and maintaining competence to ensure safe, reliable operation of nuclear power plants throughout the world. The simulator shall be specified to a reference unit and its performance validation testing shall be provided. In this study a small-break loss-of-coolant accident (SB LOCA) response of Krsko nuclear power plant (NPP) was calculated for full scope simulator verification. The investigation included five cases with varying the break size in the cold leg of reactor coolant system. The plant specific and verified RELAP5/MOD2 model of Krsko nuclear power plant (NPP), developed in the past for 1882 MWt power, was adapted for 2000 MWt power (cycle 17) including the model for replacement steam generators. The results showed that the plant system response to breaks with small break area was slower compared to breaks with larger break area. The core heatup occurred in most of the cases analyzed. The acceptance criteria for emergency core cooling system were also met. The predicted results of the SB LOCA analysis for Krsko NPP suggest that they may be used for verification of the Krsko Full Scope Simulator performance. (author)

  7. Production of 122Sb for the study of environmental pollution

    International Nuclear Information System (INIS)

    Mahdi Sadeghi; Mohammadreza Aboudzadeh; Parvin Sarabadani; Milad Enferadi

    2011-01-01

    This article presents, 122 Sb (T 1/2 = 2.723 days, I β- 97.59%) was produced via the nat Sn(p,xn) nuclear process at the AMIRS (Cyclone-30, IBA, Belgium). The electrodeposition experiments were carried out by potassium stannate trihydrate (K 2 Sn(OH) 6 ) and potassium hydroxide. The optimum conditions of the electrodeposition of tin were as follows: 40 g/L nat Sn, 20 g/L KOH, 115 g/L K 2 Sn(OH) 6 , DC current density of 5 A/dm 2 with a bath temperature of 75 deg C. The electroplated Tin-target was irradiated with 26.5 MeV protons at current of 180 μA for 20 min. Solvent extraction of no-carrier-added 122 Sb from irradiated Tin-natural target hydrochloric solution was investigated using di-n-butyl ether (C 8 H 18 O). Yields of about 3.61 MBq/μAh were experimentally obtained. (author)

  8. Synthesis and characterisation of YbPdSb

    Energy Technology Data Exchange (ETDEWEB)

    Haines, Charles R.S.; Brown, Philip A.C.; Grosche, Friedrich M. [Department of Physics, Cavendish Laboratory, University of Cambridge (United Kingdom)

    2016-07-01

    The intermetallic compound YbPdSb can form in two structures: the low temperature (LT) half-Heusler phase, in which the Yb atoms form a frustrated fcc structure, and the high temperature (HT) Pnma modification. We have prepared phase pure samples of both structures and report resistivity, magnetisation and heat capacity measurements on both. The LT phase is a Kondo lattice system showing large-moment Curie-Weiss paramagnet behaviour without any phase transition anomalies down to the lowest temperatures measured. The resistivity is rather insensitive to temperature from room temperature down to ∝50 K where it decreases steeply with further cooling. By contrast, in the HT phase the magnetic susceptibility displays weak temperature dependence and the resistivity falls with decreasing temperature in the way expected of a weakly correlated metal. These findings suggest that in contrast to the electronic state in the LT structure, the 4f-shell of Yb is completely filled in the HT structure of YbPdSb, presenting an interesting opportunity to study the interplay between lattice and electronic structure within the same compound.

  9. Pseudopotential calculations of AlSb under pressure

    Science.gov (United States)

    Algarni, H.; Al-Hagan, O. A.; Bouarissa, N.; Khan, M. A.; Alhuwaymel, T. F.

    2018-02-01

    The dependence on hydrostatic pressure of the electronic and optical properties of zinc-blende AlSb semiconducting material in the pressure range of 0-20 kbar has been reported using a pseudopotential approach. At zero pressure, our findings showed that the electron and heavy hole effective masses are 0.11 and 0.38 m0, respectively. Moreover, our results yielded values of 3.3289 and 11.08 for refractive index and high frequency dielectric constant, respectively. These results are found to be in good accord with experiment. Upon compression, all physical parameters of interest showed a monotonic behavior. The pressure-induced energy shifts for the optical transition related to band-gaps indicated that AlSb remains an indirect (D-X) band-gap semiconductor at pressures from 0 to 20 kbar. The trend in all features of interest versus pressure has been presented and discussed. It is found that the lattice parameter is reduced from 0.61355 to 0.60705 nm when pressure is raised from 0 to 20 kbar. The present investigation may be useful for mid-infrared lasers applications, detectors and communication devices.

  10. Comparisons of TRAC-PF-1 calculations with semiscale Mod-3 small-break tests S-SB-P1 and S-SB-P7

    International Nuclear Information System (INIS)

    Sahota, M.S.

    1982-01-01

    Semiscale Tests S-SB-P1 and S-SB-P7 conducted in the Semiscale Mod-3 facility at the Idaho National Engineering Laboratory are analyzed using the latest released version of the Transient Reactor Analysis Code (TRAC-PF1). The results are used to assess TRAC-PF1 predictions of thermal-hydraulic phenomena and the effects of break size and pump operation on system response during slow transients. Tests S-SB-P1 and S-SB-P7 simulated an equivalent pressurized-water-reactor (PWR) 2.5% communicative cold-leg break for early and late pump trips, respectively, with only high-pressure injection (HPI) into the cold legs. The parameters examined include break flow, primary-system pressure response, primary-system mass distribution, and core characteristics

  11. In-Ga-Zn-oxide thin-film transistors with Sb2TeOx gate insulators fabricated by reactive sputtering using a metallic Sb2Te target

    International Nuclear Information System (INIS)

    Cheong, Woo-Seok

    2011-01-01

    Using reactive sputtering, we made transparent amorphous Sb 2 TeO x thin films from a metallic Sb 2 Te target in an oxidizing atmosphere. In-Ga-Zn-oxide thin-film transistors (IGZO TFTs) with Sb 2 TeO x gate insulators deposited at room temperature showed a large hysteresis with a counter clockwise direction, which was caused by mobile charges in the gate insulators. The problems of the mobile charges was solved by using Sb 2 TeO x films formed at 250 .deg. C. After the IGZO TFT had been annealed at 200 .deg. C for 1 hour in an O 2 ambient, the mobility of the IGZO TFT was 22.41 cm 2 /Vs, and the drain current on-off ratio was ∼10 8 .

  12. Participatory epidemiology: the contribution of participatory research to epidemiology

    Directory of Open Access Journals (Sweden)

    Mario Bach

    2017-02-01

    Full Text Available Abstract Background Epidemiology has contributed in many ways to identifying various risk factors for disease and to promoting population health. However, there is a continuing debate about the ability of epidemiology not only to describe, but also to provide results which can be better translated into public health practice. It has been proposed that participatory research approaches be applied to epidemiology as a way to bridge this gap between description and action. A systematic account of what constitutes participatory epidemiology practice has, however, been lacking. Methods A scoping review was carried out focused on the question of what constitutes participatory approaches to epidemiology for the purpose of demonstrating their potential for advancing epidemiologic research. Relevant databases were searched, including both the published and non-published (grey literature. The 102 identified sources were analyzed in terms of comparing common epidemiologic approaches to participatory counterparts regarding central aspects of the research process. Exemplary studies applying participatory approaches were examined more closely. Results A highly diverse, interdisciplinary body of literature was synthesized, resulting in a framework comprised of seven aspects of the research process: research goal, research question, population, context, data synthesis, research management, and dissemination of findings. The framework specifies how participatory approaches not only differ from, but also how they can enhance common approaches in epidemiology. Finally, recommendations for the further development of participatory approaches are given. These include: enhancing data collection, data analysis, and data validation; advancing capacity building for research at the local level; and developing data synthesis. Conclusion The proposed framework provides a basis for systematically developing the emergent science of participatory epidemiology.

  13. 77 FR 34073 - Manufacturer of Controlled Substances; Notice of Application; S&B Pharma, Inc.

    Science.gov (United States)

    2012-06-08

    ... DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances; Notice of Application; S&B Pharma, Inc. Pursuant to Sec. 1301.33(a), Title 21 of the Code of Federal Regulations (CFR), this is notice that on April 4, 2012, S&B Pharma Inc., 405 South Motor Avenue, Azusa...

  14. Atomic structure of the SbCu surface alloy: A surface X-ray diffraction study

    DEFF Research Database (Denmark)

    Meunier, I.; Gay, J.M.; Lapena, L.

    1999-01-01

    The dissolution at 400 degrees C of an antimony layer deposited at room temperature on a Cu(111) substrate leads to a surface alloy with a p(root 3x root 3)R 30 degrees x 30 degrees superstructure and a Sb composition of 1/3.We present here a structural study of this Sb-Cu compound by surface X...

  15. The Cu-Sb-Se phase system at temperatures between 350 and 700 degree C

    DEFF Research Database (Denmark)

    Karup-Møller, Sven

    1999-01-01

    Phase relations were determined in the Cu-Sb-Se phase system at 300o, 400o, 450o, 500o, 600o and 700oC. Five three-component phases are present at 300oC: permingeatite (Cu3SbSe4), phase A (Cu3SbSe3, the Se-equivalent to skinnerite Cu3SbS3), phase B (CuSbSe2, the Se-equivalent to chalcostibite Cu......SbS2), phase C (Cu5.04Sb35.9Se59.1) and phase D (Cu38.8Sb6.10Se55.1). An X-ray crystallographic study is currently in progress on phase C. Phase D is present in insufficient amounts for such a study. At 400oC phase C and D does not exist and at 500oC all solid ternary phase are absent. At 450oC two...

  16. Preparation and crystal structure of Ca/sub 4/Sb/sub 2/O

    Energy Technology Data Exchange (ETDEWEB)

    Eisenmann, B; Limartha, H; Schaefer, H; Graf, H A

    1980-12-01

    The formerly described compound Ca/sub 2/Sb is to be corrected to Ca/sub 4/Sb/sub 2/O as shown by X-ray diffractometer data of single crystals and neutron diffraction diagrams of powders. The compound crystallizes in the K/sub 2/NiF/sub 4/ type structure.

  17. Ionothermal Synthesis, Structure, and Bonding of the Catena -Heteropolycation 1 ∞ [Sb 2 Se 2 ] +

    KAUST Repository

    Groh, Matthias F.

    2015-01-26

    The reaction of antimony and selenium in the Lewis-acidic ionic liquid 1-butyl-3-methyl-imidazolium tetrachloridoaluminate, [BMIm]Cl•4.7AlCl3, yielded dark-red crystals of [Sb2Se2]AlCl4. The formation starts above 160 ° C; at about 190 ° C, irreversible decomposition takes place. The compound crystallizes in the triclinic space group P 1¯ with a = 919.39(2) pm, b = 1137.92(3) pm, c = 1152.30(3) pm, α = 68.047(1)° , β = 78.115(1)° , γ = 72.530(1)° , and Z = 4. The structure is similar to that of [Sb2Te2]AlCl4 but has only half the number of crystallographically independent atoms. Polycationic chains 1∞ [Sb2Se2]+ form a pseudo-hexagonal arrangement along [011¯] ], which is interlaced by tetrahedral AlCl4 - groups. The catena-heteropolycation 1∞ [Sb2Se2]+ is a sequence of three different four-membered [Sb2Se2 ] rings. The chemical bonding scheme, established from the topological analysis of the real-space bonding indicator ELI-D, includes significantly polar covalent bonding in four-member rings withinthepolycation.Theringsareconnectedintoaninfinitechainbyhomonuclear non-polar Sb-Sb bonds and highly polar Sb-Se bonds. Half of the selenium atoms are three-bonded.

  18. Biocompatibility of GaSb thin films grown by RF magnetron sputtering

    Science.gov (United States)

    Nishimoto, Naoki; Fujihara, Junko; Yoshino, Katsumi

    2017-07-01

    GaSb may be suitable for biological applications, such as cellular sensors and bio-medical instrumentation because of its low toxicity compared with As (III) compounds and its band gap energy. Therefore, the biocompatibility and the film properties under physiological conditions were investigated for GaSb thin films with or without a surface coating. GaSb thin films were grown on quartz substrates by RF magnetron sputtering, and then coated with (3-mercaptopropyl) trimethoxysilane (MPT). The electrical properties, surface morphology, and crystal structure of the GaSb thin film were unaffected by the MPT coating. The cell viability assay suggested that MPT-coated GaSb thin films are biocompatible. Bare GaSb was particularly unstable in pH9 buffer. Ga elution was prevented by the MPT coating, although the Ga concentration in the pH 9 buffer was higher than that in the other solutions. The surface morphology and crystal structure were not changed by exposure to the solutions, except for the pH 9 buffer, and the thin film properties of MPT-coated GaSb exposed to distilled water and H2O2 in saline were maintained. These results indicate that MPT-coated GaSb thin films are biocompatible and could be used for temporary biomedical devices.

  19. Effect of laser irradiation on Ag4In12Sb56Te28

    Science.gov (United States)

    Chinnusamy, Rangasami

    2018-04-01

    Ag4In12Sb56Te28 has been synthesized by melt-quench method. Phase homogeneity, crystal structure and effect of laser irradiation have been investigated using X-ray diffraction (XRD) and Raman spectroscopy. Rietveld refinement of crystal structure revealed that Ag4In12Sb56Te28 is a multiphase system with AgIn3Te5, Sb8Te3 and Sb phases. Combined optical microscopy and Raman spectroscopy have been used to understand the distribution of different phases on the surface of the samples, which substantiated the results of Rietveld analysis. Interaction of 20 mW laser beam with samples has been investigated using Raman measurements. The results have shown that regions with large phase fraction of AgIn3Te5 become amorphous during laser-sample interaction, but the starting phase remains nearly same after the interaction. Regions with AgIn3Te5 and nearly equal or larger amount of Sb8Te3 have shown significant growth of α-Sb2O3 during and after laser-sample interaction. Regions rich in Sb have shown formation of AgIn3Te5 and growth of α-Sb2O3 during and after interaction. These observations have been explained based on the maximum temperature rise at different regions during laser-sample interaction.

  20. Fluorometric and molecular docking investigation on the binding characteristics of SB202190 to human serum albumin

    International Nuclear Information System (INIS)

    Nasruddin, Ahmad N.; Feroz, Shevin R.; Mukarram, Abdul K.; Mohamad, Saharuddin B.; Tayyab, Saad

    2016-01-01

    The interaction of SB202190, a p38 mitogen-activated protein kinase inhibitor with the main drug transporter in human circulation, human serum albumin (HSA) was studied using fluorescence spectroscopy and in silico docking methods. The association constant, K a of the binding reaction was determined to be 3.24±0.07×10 4 M −1 at 25 °C based on fluorescence quenching titration results. The values of enthalpy change and entropy change for the interaction were found as −8.54 kJ mol −1 and 58.01 J mol −1 K −1 , respectively. Both thermodynamic data and docking results suggested the involvement of hydrophobic and van der Waals forces in the complex formation. Three-dimensional fluorescence data of SB202190–HSA complex demonstrated significant changes in the microenvironment around the protein fluorophores upon drug binding. Comparison of HSA thermograms obtained in the absence and the presence of SB202190 suggested improved protein thermal stability upon complexation with the drug. Competitive drug displacement results as well as modeling data concluded the preferred binding site of SB202190 on HSA as Sudlow's site I. - Highlights: • SB202190 interacts with HSA with moderate affinity. • Involvement of hydrophobic and van der Waals forces in SB202190 binding. • SB202190 binding results in microenvironmental changes around fluorophores. • Sudlow's site I is the preferred binding site of SB202190.

  1. Investigation of broken symmetry of Sb/Cu(111) surface alloys by VT-STM

    CSIR Research Space (South Africa)

    Ndlovu, GF

    2011-07-01

    Full Text Available This work present an in situ Variable Temperature Scanning Tunneling Microscopy (VT-STM) study of the Sb/Cu(111) system studied at various temperatures. The experimental data support a structural model in which Sb atoms displace up to 1...

  2. Bismuth-induced restructuring of the GaSb(110) surface

    DEFF Research Database (Denmark)

    Gemmeren, T. van; Lottermoser, L.; Falkenberg, G.

    1998-01-01

    The structure of the GaSb(110)(1 x 2)-Bi reconstruction has been solved using surface x-ray diffraction, scanning tunneling microscopy, and photoelectron spectroscopy. The ideal GaSb(110) surface is terminated with zigzag chains of anions and cations running in the [1 (1) over bar 0] direction...

  3. Room temperature synthesis of crystalline Sb2S3 for SnO2 ...

    Indian Academy of Sciences (India)

    attention of researchers owing to their low cost, simple fabrication technique and .... The typical SEM images of as-deposited Sb2S3 in figure 3a show the .... reduce back the excited Sb2S3 to its ground state and to set the system for next ...

  4. SB431542 treatment promotes the hypertrophy of skeletal muscle fibers but decreases specific force

    NARCIS (Netherlands)

    Watt, K.I.; Jaspers, R.T.; Atherton, P.; Smith, K.; Rennie, M.J.; Ratkevicius, A.; Wackerhage, H.

    2010-01-01

    The small molecule inhibitor SB431542 inhibits activin type I receptors. The muscle growth-inhibitor myostatin binds to and signals via these receptors. The aim of this study was to test the hypothesis that SB431542 can inhibit myostatinrelated Smad signaling and induce muscle growth in cultured

  5. Orientation control and thermoelectric properties of FeSb2 films

    DEFF Research Database (Denmark)

    Sun, Ye; Zhang, Eryun; Johnsen, Simon

    2010-01-01

    FeSb2 has a high potential for technological applications due to its colossal thermoelectric power, giant carrier mobility and large magnetoresistance. Earlier, growth of lang1 0 1rang-textured FeSb2 films on quartz (0 0 0 1) substrates has been reported. Here magnetron sputtering is used to obtain...

  6. Tunable surface wettability and water adhesion of Sb2S3 micro-/nanorod films

    International Nuclear Information System (INIS)

    Zhong, Xin; Zhao, Huiping; Yang, Hao; Liu, Yunling; Yan, Guoping; Chen, Rong

    2014-01-01

    Antimony sulfide (Sb 2 S 3 ) films were successfully prepared by spin coating Sb 2 S 3 micro-/nanorods with different sizes on glass slides, which was synthesized via a facile and rapid microwave irradiation method. The prepared Sb 2 S 3 micro-/nanorods and films were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (CA). The as-prepared Sb 2 S 3 films exhibited different surface wettabilities ranging from superhydrophilicity to superhydrophobicity, which was strongly dependent on the diameter of Sb 2 S 3 micro-/nanorod. Sb 2 S 3 film made by nanorods possessed superhydrophobic surface and high water adhesive property. After surface modification with stearic acid, the superhydrophobic surface exhibited an excellent self-cleaning property owing to its low adhesive force. The clarification of three possible states including Wenzel's state, “Gecko” state and Cassie's state for Sb 2 S 3 film surfaces was also proposed to provide a better understanding of interesting surface phenomena on Sb 2 S 3 films.

  7. Two-mode Diode-laser Spectroscopy with a InAsSb/InAsSbP Laser near 3.6 ćm

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Danilova, A. P.; Imenkov, A. N.; Kolchanova, N. M.; Sherstnev, V. V.; Yakovlev, Yu. P.

    1999-01-01

    Roč. 33, č. 12 (1999), s. 1322-1327 ISSN 1063-7826 R&D Projects: GA AV ČR IAA4040708 Institutional research plan: CEZ:A54/98:Z4-040-9-ii Keywords : output frequency of InAsSb/InAsSbP * current dependence Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.565, year: 1999

  8. Microwave radiation absorption and Shubnikov-de Haas oscillations in semimetal InAs/GaSb/AlSb composite quantum wells

    Czech Academy of Sciences Publication Activity Database

    Mikhailova, M. P.; Veinger, A.I.; Kochman, I.V.; Semenikhin, P.V.; Kalinina, K.V.; Parfeniev, R.V.; Berezovets, V.A.; Safonchik, M.O.; Hospodková, Alice; Pangrác, Jiří; Zíková, Markéta; Hulicius, Eduard

    2016-01-01

    Roč. 10, č. 4 (2016), 1-8, č. článku 046013. ISSN 1934-2608 R&D Projects: GA ČR GA13-15286S; GA MŠk LO1603 Institutional support: RVO:68378271 Keywords : Shubnikov-de Haas oscillations * microwave absorption * electron-paramagnetic resonance * composite quantum wells * InAs/GaSb/AlSb * MOVPE Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.325, year: 2016

  9. The Enzyme Activity and Substrate Specificity of Two Major Cinnamyl Alcohol Dehydrogenases in Sorghum (Sorghum bicolor), SbCAD2 and SbCAD4.

    Science.gov (United States)

    Jun, Se-Young; Walker, Alexander M; Kim, Hoon; Ralph, John; Vermerris, Wilfred; Sattler, Scott E; Kang, ChulHee

    2017-08-01

    Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in monolignol biosynthesis, reducing sinapaldehyde, coniferaldehyde, and p -coumaraldehyde to their corresponding alcohols in an NADPH-dependent manner. Because of its terminal location in monolignol biosynthesis, the variation in substrate specificity and activity of CAD can result in significant changes in overall composition and amount of lignin. Our in-depth characterization of two major CAD isoforms, SbCAD2 (Brown midrib 6 [bmr6]) and SbCAD4, in lignifying tissues of sorghum ( Sorghum bicolor ), a strategic plant for generating renewable chemicals and fuels, indicates their similarity in both structure and activity to Arabidopsis ( Arabidopsis thaliana ) CAD5 and Populus tremuloides sinapyl alcohol dehydrogenase, respectively. This first crystal structure of a monocot CAD combined with enzyme kinetic data and a catalytic model supported by site-directed mutagenesis allows full comparison with dicot CADs and elucidates the potential signature sequence for their substrate specificity and activity. The L119W/G301F-SbCAD4 double mutant displayed its substrate preference in the order coniferaldehyde > p -coumaraldehyde > sinapaldehyde, with higher catalytic efficiency than that of both wild-type SbCAD4 and SbCAD2. As SbCAD4 is the only major CAD isoform in bmr6 mutants, replacing SbCAD4 with L119W/G301F-SbCAD4 in bmr6 plants could produce a phenotype that is more amenable to biomass processing. © 2017 American Society of Plant Biologists. All Rights Reserved.

  10. 纳米 Sb2O3/MMA原位乳液聚合研究%Nano-sized Sb2O3/MMA in-situ emulsion polymerization

    Institute of Scientific and Technical Information of China (English)

    谭菁; 吴红兵; 胡红春; 张经武; 解孝林

    2002-01-01

    研究了纳米 Sb2O3/MMA体系的原位乳液聚合反应.结果表明,纳米 Sb2O3对 MMA的聚合无阻聚作用,表面包覆的聚甲基丙烯酸甲酯能有效地解决纳米粒子的团聚问题 .

  11. Growth of InTlSB and InTlP for Long Wavelength Infrared Detector Applications

    National Research Council Canada - National Science Library

    Razeghi, M

    1998-01-01

    .... Other novel alloys such as InAsSb and InSbBi are also investigated. The structural, optical, and electrical properties of these novel materials have been investigated in detail with various ex-situ characterization techniques...

  12. Characteristics of phase transition and separation in a In-Ge-Sb-Te system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Jin [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Jang, Moon Hyung [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States); Park, Seung-Jong [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Cho, Mann-Ho, E-mail: mh.cho@yonsei.ac.kr [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Ko, Dae-Hong [Department of Material Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer InGeSbTe films were fabricated via co-deposition stoichiometric GST and IST targets. Black-Right-Pointing-Pointer As the amount of IST was increased in InGeSbTe, the value for V{sub th} and the phase transition temperature were increased. Black-Right-Pointing-Pointer The phase separation in InGeSbTe is caused by differences in the enthalpy change for formation and different atomic concentrations. - Abstract: In-doped GeSbTe films were deposited by ion beam sputtering deposition (IBSD) using Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) and In{sub 3}Sb{sub 1}Te{sub 2} (IST) as targets. The phase change characteristics of the resulting films were then investigated by electrical measurements, including static testing, in situ 4-point R{sub s} measurements, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The threshold voltage of the films increased, with increasing levels of IST. This phenomenon is consistent with the increased crystallization temperature in X-ray data and in situ 4-point R{sub s} data. In addition, in In{sub 28}Ge{sub 12}Sb{sub 26}Te{sub 34}, multiple V{sub th} values with a stepwise change are observed. The minimum time for the crystallization of InGeSbTe films was shorter than that for GST. X-ray data and Raman data for the crystalline structure show that phase separation to In{sub 2}Te{sub 3} occurred in all of the InGeSbTe samples after annealing at 350 Degree-Sign C. Moreover, in the case of InGeSbTe films with high concentrations of In (28 at.%), Sb phase separation was also observed. The observed phases indicate that the origin of the phase separation of InGeSbTe films is from the enthalpy change of formation and differences in Ge-Te, In-Te, Sb-Te, In-Sb and In-In bond energies.

  13. Optimization of growth parameters for MOVPE-grown GaSb and Ga{sub 1-x}In{sub x}Sb

    Energy Technology Data Exchange (ETDEWEB)

    Miya, S.S.; Wagener, V. [Department of Physics, Private Bag X 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6001 (South Africa); Botha, J.R., E-mail: reinhardt.botha@nmmu.ac.za [Department of Physics, Private Bag X 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6001 (South Africa)

    2012-05-15

    The triethylgallium/trimethylantimony (TEGa/TMSb) precursor combination was used for the metal-organic vapour phase epitaxial growth of GaSb at a growth temperature of 520 Degree-Sign C at atmospheric pressure. Trimethylindium was added in the case of Ga{sub 1-x}In{sub x}Sb growth. The effects of group V flux to group III flux ratio (V/III ratio) on the crystallinity and optical properties of GaSb layers are reported. It has been observed from the crystalline quality and optical properties that nominal V/III ratios of values greater than unity are required for GaSb epitaxial layers grown at this temperature. It has also been shown that Ga{sub 1-x}In{sub x}Sb can be grown using TEGa as a source of gallium species at atmospheric pressure. The relationship between Ga{sub 1-x}In{sub x}Sb vapour composition and solid composition has been studied at a V/III ratio of 0.78.

  14. Effects of Radiative Recombination and Photon Recycling on Minority Carrier Lifetime in Epitaxial GaINAsSb Lattice-matched to GaSb

    International Nuclear Information System (INIS)

    S Anikeev; D Donetsky; G Belenky; S Luryl; CA Wang; DA Shiau; M Dashiell; J Beausang; G Nichols

    2004-01-01

    Radiative coefficient (B) is a fundamental recombination parameter which is of importance for a variety of optoelectronic minority carrier devices. Radiative recombination was comprehensively studied for wide-bandgap III-V compounds, while for 0.5-0.6 eV materials experimental data are quite limited and demonstrate significant spreading. Here we report excess carrier lifetime in isotype double heterostructures (DHs) of 0.54-eV p-GaInAsSb capped with p-AlGaAsSb, and grown lattice-matched to GaSb. Lifetime was measured by time-resolved photoluminescence (dynamic lifetime) as well as by optical response to sinusoidal excitation (static lifetime). Wide range of GaInAsSb layer thickness was used to separate contributions from interface and radiative recombination processes. Radiative coefficient and recombination velocity at GaInAsSb/AlGaAsSb heterointerface were determined. Temperature dependence of lifetime demonstrated significant contribution of radiative effects to the total recombination

  15. The electronic band structures of InNxAs1-x, InNxSb1-x and InAsxSb1-x alloys

    International Nuclear Information System (INIS)

    Mohammad, Rezek; Katircioglu, Senay

    2009-01-01

    The band gap bowings of InN x As 1-x , InN x Sb 1-x , and InAs x Sb 1-x alloys defined by the optimized lattice constants are investigated using empirical tight binding (ETB) method. The present ETB energy parameters which take the nearest neighbor interactions into account with sp 3 d 2 basis are determined to be sufficient to provide a typical feature for the band gap bowings of the alloys. The band gap bowing parameter is found to be relatively large in both InN x As 1-x and InN x Sb 1-x compared to InAs x Sb 1-x alloys. Moreover, the variation of the fundamental band gaps of InN x Sb 1-x alloys is sharper than that of InN x As 1-x alloys for small concentrations of N. Besides, a small amount of nitrogen is determined to be more effective in InN x Sb 1-x than in InN x As 1-x alloys to decrease the corresponding effective masses of the electrons around Γ points

  16. Nanoscale nuclei in phase change materials: Origin of different crystallization mechanisms of Ge2Sb2Te5 and AgInSbTe

    International Nuclear Information System (INIS)

    Lee, Bong-Sub; Bogle, Stephanie N.; Darmawikarta, Kristof; Abelson, John R.; Shelby, Robert M.; Retter, Charles T.; Burr, Geoffrey W.; Raoux, Simone; Bishop, Stephen G.

    2014-01-01

    Phase change memory devices are based on the rapid and reversible amorphous-to-crystalline transformations of phase change materials, such as Ge 2 Sb 2 Te 5 and AgInSbTe. Since the maximum switching speed of these devices is typically limited by crystallization speed, understanding the crystallization process is of crucial importance. While Ge 2 Sb 2 Te 5 and AgInSbTe show very different crystallization mechanisms from their melt-quenched states, the nanostructural origin of this difference has not been clearly demonstrated. Here, we show that an amorphous state includes different sizes and number of nanoscale nuclei, after thermal treatment such as melt-quenching or furnace annealing is performed. We employ fluctuation transmission electron microscopy to detect nanoscale nuclei embedded in amorphous materials, and use a pump-probe laser technique and atomic force microscopy to study the kinetics of nucleation and growth. We confirm that melt-quenched amorphous Ge 2 Sb 2 Te 5 includes considerably larger and more quenched-in nuclei than its as-deposited state, while melt-quenched AgInSbTe does not, and explain this contrast by the different ratio between quenching time and nucleation time in these materials. In addition to providing insights to the crystallization process in these technologically important devices, this study presents experimental illustrations of temperature-dependence of nucleation rate and growth speed, which was predicted by theory of phase transformation but rarely demonstrated

  17. Effect of Sb on physical properties and microstructures of laser nano/amorphous-composite film

    International Nuclear Information System (INIS)

    Li, Jia-Ning; Gong, Shui-Li; Sun, Mei; Shan, Fei-Hu; Wang, Xi-Chang; Jiang, Shuai

    2013-01-01

    A nano/amorphous-composite film was fabricated by laser cladding (LC) of the Co–Ti–B 4 C–Sb mixed powders on a TA15 alloy. Such film mainly consisted of Ti–Al, Co–Ti, Co–Sb intermetallics, TiC, TiB 2 , TiB, and the amorphous phases. Experimental results indicated that the crystal systems of TiB 2 (hexagonal)/TiC (cubic) and Sb (rhombohedral) played important role on the formation of such film. Due to the mismatch of these crystals systems and mutual immiscibility of the metallic components, Sb was not incorporated in TiB 2 /TiC, but formed separate nuclei during the film growth. Thus, the growth of TiB 2 /TiC was stopped by the Sb nucleus in such LC molten pool, so as to form the nanoscale particles

  18. Structural instability and photoacoustic study of AlSb prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Triches, D.M.; Souza, S.M.; Poffo, C.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Lima, J.C. de, E-mail: fsc1jcd@fsc.ufsc.b [Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Grandi, T.A. [Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Biasi, R.S. de [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)

    2010-09-03

    High-purity elemental Al and Sb powders were blended with equiatomic composition and submitted to mechanical alloying. For all milling times, the milled powders showed a mixture of AlSb and elemental Sb. The largest amount of AlSb was reached for milling times between 7 and 10 h. For milling times larger than 10 h, decomposition of AlSb was observed. The volume fractions of the crystalline and interfacial components were estimated using the X-ray diffraction pattern of a sample milled for 10 h. Photoacoustic absorption spectroscopy (PAS) was used to determine the thermal diffusivity and other heat transport parameters in the same sample. A combination of XRD and PAS data was used to estimate the thermal diffusivity of the interfacial component, which has a significant contribution to the thermal diffusivity of the sample.

  19. Structural instability and photoacoustic study of AlSb prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Triches, D.M.; Souza, S.M.; Poffo, C.M.; Lima, J.C. de; Grandi, T.A.; Biasi, R.S. de

    2010-01-01

    High-purity elemental Al and Sb powders were blended with equiatomic composition and submitted to mechanical alloying. For all milling times, the milled powders showed a mixture of AlSb and elemental Sb. The largest amount of AlSb was reached for milling times between 7 and 10 h. For milling times larger than 10 h, decomposition of AlSb was observed. The volume fractions of the crystalline and interfacial components were estimated using the X-ray diffraction pattern of a sample milled for 10 h. Photoacoustic absorption spectroscopy (PAS) was used to determine the thermal diffusivity and other heat transport parameters in the same sample. A combination of XRD and PAS data was used to estimate the thermal diffusivity of the interfacial component, which has a significant contribution to the thermal diffusivity of the sample.

  20. Magnetic and structural properties of Bi(2223doped by pb and Sb

    Directory of Open Access Journals (Sweden)

    H. Salamati

    1998-04-01

    Full Text Available   In a systematic approach, we have investigated the effect of the presence of Pb and Sb in the Bi site in a BSCCO (2223 phase superconductor. There are some contradictory reports in substitution of Sb in the Bi site. Some researchers report an increase in the Tc of these materials. So, we have made an accurate stoichiometry of these superconductors and selected extra pure starting materials with appropriate ratios of Pb+Sb.   The susceptility of these samples have been measured and the structures of the systems have been studied by SEM and XRD. The results of this investigation show that, Although the presence of Pb is essential for formation of (2223 phase, but addition of small amount of Sb helps to stabilize and enhance the ratio of higher phase. Our results show that, presence of Sb would raise the critical current density, but would not affect the Tc of these superconductors.