199 research outputs found
Structural interaction with control systems
A monograph which assesses the state of the art of space vehicle design and development is presented. The monograph presents criteria and recommended practices for determining the structural data and a mathematical structural model of the vehicle needed for accurate prediction of structure and control-system interaction; for design to minimize undesirable interactions between the structure and the control system; and for determining techniques to achieve the maximum desirable interactions and associated structural design benefits. All space vehicles are treated, including launch vehicles, spacecraft, and entry vehicles. Important structural characteristics which affect the structural model used for structural and control-system interaction analysis are given
A terminal guidance scheme for lifting body entry vehicles
Perturbation feedback guidance for terminal phase of lifting body entry vehicl
Total Energy Expenditure and Body Composition of Children with Developmental Disabilities
Background Obesity prevalence is increased in children with developmental disabilities, specifically in children with spina bifida and Down syndrome. Energy expenditure, a critical aspect of weight management, has been extensively studied in the typically developing population, but not adequately studied in children with developmental disabilities. Objective Determine energy expenditure, fat-free mass and body fat percentile and the impact of these findings on recommended caloric intake in children with spina bifida and Down syndrome. Methods/Measures This pilot study included 36 children, 18 with spina bifida, 9 with Down syndrome and 9 typically developing children. Half of the children with spina bifida were non-ambulatory. Doubly labeled water was used to measure energy expenditure and body composition. Descriptive statistics described the sample and MANOVA and ANOVA methods were used to evaluate differences between groups. Results Energy expenditure was significantly less for children with spina bifida who primarily used a wheelchair (p = .001) and children with Down syndrome (p = .041) when compared to children without a disability when adjusted for fat-free mass. However, no significant difference was detected in children with spina bifida who ambulated without assistance (p = .072). Conclusions Children with spina bifida and Down syndrome have a significantly decreased energy expenditure which directly impacts recommended caloric intake. No significant difference was detected for children with spina bifida who ambulated, although the small sample size of this pilot study may have limited these findings. Validating these results in a larger study is integral to supporting successful weight management of these children
A Non-Anesthetized Mouse Model for Recording Sensory Urinary Bladder Activity
The goal of this study was to develop an in vivo awake mouse model for extracellular bladder sensory nerve recording. A bipolar 125-μm silver electrode was positioned under a single postganglionic bladder nerve. Efferent nerve signals were eliminated by tying off the postganglionic bladder nerve between the major pelvic ganglion and the recording electrode. Sensory nerve activity was measured in the conscious animals 48 h after surgery during continuous intravesical infusion of 0.9% saline/0.5% acetic acid followed by 0.5% acetic acid with capsazepine (10 μM) at a rate of 0.75 ml/h. Continuous infusion of 0.9% NaCl led to a gradual increase in the frequency of sensory nerve firing that peaked upon reaching threshold pressure. Non-micturition contractions were observed in some animals during filling and other animals exhibited only minimal pressure fluctuations; both types of events were associated with a rise in sensory nerve activity. Intravesical infusion of 0.5% acetic acid reduced the intermicturition interval. This was associated with a 2.1-fold increase in bladder pressure during filling and a two-fold increase at both threshold and micturition pressures. Concurrent with these changes, sensory activity increased 2.8-fold during filling and 2.4-fold at threshold pressure. Subsequent intravesical infusion of capsazepine in 0.5% acetic acid reduced filling and threshold pressures by 21 and 31.2%, respectively, and produced corresponding decreases of 36 and 23.4% in sensory nerve activity. The current study shows that multifiber sensory nerve recordings can be reproducibly obtained from conscious mice
Fathers’ Involvement in Child Health Care: Associations with Prenatal Involvement, Parents’ Beliefs, and Maternal Gatekeeping
Using data from 182 dual-earner couples experiencing the transition to parenthood, this study examined associations between prenatal involvement, gender role beliefs, and maternal gatekeeping and new fathers’ involvement in child health care. Results indicated that prenatal father involvement was associated with both fathers’ direct engagement in child health care and fathers’ perceived influence in child health-related decision-making. Fathers also demonstrated greater direct engagement in child health care when mothers held more nontraditional beliefs about gender roles. Moreover, when mothers were more encouraging of fathers’ involvement in childrearing, fathers felt more influential in child health-related decision-making, whereas when mothers engaged in greater gate closing behavior, fathers with more traditional gender role beliefs felt less influential in child health-related decision-making. This study suggests that fathers’ prenatal involvement, mothers’ beliefs, and maternal gatekeeping may play a role in the development of new fathers’ involvement in child health care at the transition to parenthood
BMI as a Predictor for Potential Difficult Tracheal Intubation in Males
Introduction: Difficult tracheal intubation is a common source of mortality and morbidity insurgical and critical care settings. The incidence reported of difficult tracheal intubation is 0.1 to 13%and reaches 14% in the obese population. The objective of our retrospective study was to investigateand compare the utility of BMI as indicator of difficult tracheal intubation in males and females.Material and methods: We performed a retrospective chart review of patients who underwentabdominal surgeries with ASA I to V under general anesthesia requiring endotracheal intubation. Thefollowing information was obtained from medical records for analysis: gender, age, height, weight,BMI, length of patient stay in the Post Anesthesia Care Unit (PACU), past medical history of sleepapnea, Mallampati score, and the ASA classification assigned by the anesthesia care providerperforming the endotracheal intubation.Results: Of 4303 adult patients, 1970 (45.8%) men and 2333 (54.2%) women, were enrolled in thestudy. Within this group, a total of 1673 (38.9%) patients were morbidly obese. The average age of thestudy group was 51.4 ± 15.8 and the average BMI was 29.7 ± 8.2 kg/m². The overall incidence of theencountered difficult intubations was 5.23%, or 225 subjects. Thus, our results indicate that BMI is areliable predictor of difficult tracheal intubation predominantly in the male population; another strongpredictor, with a positive linear correlation, being the Mallampati score.Conclusions: In conclusion, our data shows that BMI is a reliable indicator of potential difficult trachealintubation only in male surgical patients
Self-Compassion and Depressive Symptoms as Determinants of Sensitive Parenting: Associations with Sociodemographic Characteristics in a Sample of Mothers and Toddlers
Parenting that is sensitive and responsive to children’s needs has been shown to support children’s optimal growth and development in many cultural contexts. Numerous studies suggest that self-compassion is positively related to sensitive parenting. Despite growing research interest linking self-compassion to responsive parenting, there are considerable gaps in the literature. The current study examined the associations between self-compassion, depressive symptoms, socioeconomic status, and sensitive parenting. Data was obtained from a cohort study of 300 families in central Ohio enrolled when children were a mean (SD) calendar age of 18.2 (0.7) months. Children of all gestational ages at birth are included, and 37% were born preterm (<37 weeks’ gestation). Observational protocols were used to determine maternal sensitivity in a semi-structured play setting. Self-compassion was assessed with the Self-Compassion Scale when children were 24 months old. Self-compassion was not associated with sociodemographic characteristics including maternal education, household income, child sex and gestational age. In unadjusted regression models, depressive symptoms were related to sensitive parenting (B = −0.036, SE = 0.016, p = 0.03), but self-compassion was not a statistically significant predictor (p = 0.35) of sensitivity, and neither self-compassion nor depressive symptoms were statistically significant predictors of sensitive parenting after adjustment for covariates. Considerations for future studies are discussed
Parenting and children’s representations of family predict disruptive and callous-unemotional behaviors.
Data from a large prospective longitudinal study (n = 1,239) was used to investigate the association between observed sensitive parenting in early childhood and children's representations of family relationships as measured by the Family Drawing Paradigm (FDP) in first grade as well as the extent to which these representations partially mediate the influences of early caregiving experiences on later conduct problems and callous-unemotional behaviors. A structural equation modeling approach revealed that less sensitive parenting at 24, 36, and 58 months predicts higher levels of conduct problems (CP) and callous-unemotional (CU) behaviors in first grade controlling for earlier measures of CP and CU behaviors. Results also indicated that greater dysfunctional family representations, as assessed with the FDP, are significantly associated with higher CU behaviors in the first grade, but not CP. Finally, a test of the indirect pathway suggests that children's dysfunctional family representations may, in part, account for the association between sensitive parenting and CU behaviors
Mothers' and fathers' sensitivity and children's cognitive development in low-income, rural families
This study examines associations between maternal and paternal sensitive parenting and child cognitive development across the first 3 years of life using longitudinal data from 630 families with co-residing biological mothers and fathers. Sensitive parenting was measured by observational coding of parent-child interactions and child cognitive development was assessed with the Bayley Scales of Infant Development and the Wechsler Preschool and Primary Scales of Intelligence. There were multiple direct and indirect associations between parenting and cognitive development across mothers and fathers, suggesting primary effects, carry-forward effects, spillover effects across parents, and transactional effects across parents and children. Associations between parenting and cognitive development were statistically consistent across mothers and fathers, and the cumulative effects of early parenting on later cognitive development were comparable to the effects of later parenting on later cognitive development. As interpreted through a family systems framework, findings suggest additive and interdependent effects across parents and children
The critical role of intracellular zinc in adenosine A2 receptor activation induced cardioprotection against reperfusion injury
Exogenous zinc can protect cardiac cells from reperfusion injury, but the exact roles of endogenous zinc in the pathogenesis of reperfusion injury and in adenosine A2 receptor activation-induced cardioprotection against reperfusion injury remain unknown. Adenosine A1/A2 receptor agonist 5′-(N-ethylcarboxamido) adenosine (NECA) given at reperfusion reduced infarct size in isolated rat hearts subjected to 30 min ischemia followed by 2 h of reperfusion. This effect of NECA was partially but significantly blocked by the zinc chelator N,N,N′,N′-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN), and ZnCl2 given at reperfusion mimicked the effect of NECA by reducing infarct size. Total tissue zinc concentrations measured with inductively coupled plasma optical emission spectroscopy (ICPOES) were decreased upon reperfusion in rat hearts and this was reversed by NECA. NECA increased intracellular free zinc during reperfusion in the heart. Confocal imaging study showed a rapid increase in intracellular free zinc in isolated rat cardiomyocytes treated with NECA. Further experiments revealed that NECA increased total zinc levels upon reperfusion in mitochondria isolated from isolated hearts. NECA attenuated mitochondrial swelling upon reperfusion in isolated hearts and this was inhibited by TPEN. Similarly, NECA prevented the loss of mitochondrial membrane potential (ΔΨm) caused by oxidant stress in cardiomyocytes. Finally, both NECA and ZnCl2 inhibited the mitochondrial metabolic activity. NECA-induced cardioprotection against reperfusion injury is mediated by intracellular zinc. NECA prevents reperfusion-induced zinc loss and relocates zinc to mitochondria. The inhibitory effects of zinc on both the mPTP opening and the mitochondrial metabolic activity may account for the cardioprotective effect of NECA
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