Effects of naps at work on the sleepiness of 12-hour night shift nursing personnel

Background and objective: The purpose of the present study was to evaluate the effects of a nap at work on the sleepiness of 12-hour, night-shift (registered and assistant) nursing personnel.Methods: Twelve nurses filled out daily logs, the Karolinska Sleepiness Scale (KS), and wore wrist actigraphs for two periods of four continuous days.Results: Mean nap duration during the night shifts was 138.3 (SD+39.8) minutes. The mean sleepiness level assessed by the KS score was lower, 3.3 (SD±1.6), when the nap was taken during the first span (00:01 - 03:00h) of the night shift, compared with 6.6 (SD±1.0) when there was no nap. The mean sleepiness level assessed by the KS score was also lower, 3.6 (SD±0.9), when the nap was taken during the second span (03:01 - 06:00h) of the night shift, compared with 7.0 (SD±1.1) when there was no nap. Thus, napping either during the first or second part of the night shift reduces sleepiness of 12-hour, night-shift nursing personnel. Moreover, the mean duration of the first sleep episode after night work was longer in those who did not nap than in those who did. Conclusions: The results of this study show that napping during the 12-hour, night-shift results in less sleepiness at work and less need for recovery sleep after work

Exercise x BCAA supplementation in young trained rats: what are their effects on body growth?

The purpose of this study was to evaluate whether Branched-chain amino acids (BCAAs) supplementation had any beneficial effects on growth and metabolic parameters of young rats submitted to chronic aerobic exercise. Thirty-two young rats (age: 21-d) were randomly assigned to four experimental groups (n = 8): Supplemented Trained (Sup/Ex), Control Trained (Ctrl/Ex), Supplemented Sedentary (Sup/Sed) and Control Sedentary (Ctrl/Sed). The trained groups underwent a five-week swimming protocol and received supplemented (45 mg BCAA/body weight/day) or control ration. Trained animals presented a lower body length and a higher cartilage weight, regardless of supplementation. Physical activity was responsible for a substantial reduction in proteoglycan synthesis in cartilage tissue, and BCAA supplementation was able to attenuate this reduction and also to improve glycogen stores in the liver, although no major differences were found in body growth associated to this supplementation.

Mobility and social network effects on extremist opinions

Understanding the emergence of extreme opinions and in what kind of environment they might become less extreme is a central theme in our modern globalized society. A model combining continuous opinions and observed discrete actions (CODA) capable of addressing the important issue of measuring how extreme opinions might be has been recently proposed. In this paper I show extreme opinions to arise in a ubiquitous manner in the CODA model for a multitude of social network structures. Depending on network details reducing extremism seems to be possible. However, a large number of agents with extreme opinions is always observed. A significant decrease in the number of extremists can be observed by allowing agents to change their positions in the network.

Responsiveness to exercise training in juvenile dermatomyositis: a twin case study

Background: Patients with juvenile dermatomyositis (JDM) often present strong exercise intolerance and muscle weakness. However, the role of exercise training in this disease has not been investigated. Purpose: this longitudinal case study reports on the effects of exercise training on a 7-year-old patient with JDM and on her unaffected monozygotic twin sister, who served as a control. Methods: Both the patient who was diagnosed with JDM as well as her healthy twin underwent a 16-week exercise training program comprising aerobic and strengthening exercises. We assessed one repetition-maximum (1-RM) leg-press and bench-press strength, balance, mobility and muscle function, blood markers of inflammation and muscle enzymes, aerobic conditioning, and disease activity scores. As a result, the healthy child had an overall greater absolute strength, muscle function and aerobic conditioning compared to her JDM twin pair at baseline and after the trial. However, the twins presented comparable relative improvements in 1-RM bench press, 1-RM leg press, VO(2peak), and time-to-exhaustion. The healthy child had greater relative increments in low-back strength and handgrip, whereas the child with JDM presented a higher relative increase in ventilatory anaerobic threshold parameters and functional tests. Quality of life, inflammation, muscle damage and disease activity scores remained unchanged. Results and Conclusion: this was the first report to describe the training response of a patient with non-active JDM following an exercise training regimen. The child with JDM exhibited improved strength, muscle function and aerobic conditioning without presenting an exacerbation of the disease.

The acute effects of varying strength exercises bouts on 5km running

This study investigated if there were acute interference effects of strength exercises on subsequent continuous and intermittent 5Km aerobic exercises. Eleven physically active males (23.1 +/- 3.1 yrs, 1.75 +/- 0.07 m, 70.5 +/- 8.8 kg, and 58.2 +/- 8.3 VO(2)max) performed the following experimental sessions: A) 5 sets of 5 RM on the leg press followed by a 5km run performed continuously (average velocity of the first and second ventilatory thresholds, nu Delta 50), B) 5 sets of 5 RM on the leg press followed by a 5km run performed intermittently (1 min run at the nu VO(2)max : 1 min of rest); C) 2 sets of 15 RM on the leg press followed by a 5km continuous run; and D) 2 sets of 15 RM on the leg press followed by a 5km intermittent run. Heart rate, blood lactate concentration, rate of perceived exertion, and VO(2) at the first and the fifth km were considered for statistical purposes. There were no significant effects of both strength bouts on any of the variables associated with endurance performance (p > 0.05). It seems that both maximum and strength endurance bouts do not acutely impair aerobic performance.

Effects of Variations in Nonlinear Damping Coefficients on the Parametric Vibration of a Cantilever Beam with a Lumped Mass

Uncertainties in damping estimates can significantly affect the dynamic response of a given flexible structure. A common practice in linear structural dynamics is to consider a linear viscous damping model as the major energy dissipation mechanism. However, it is well known that different forms of energy dissipation can affect the structure's dynamic response. The major goal of this paper is to address the effects of the turbulent frictional damping force, also known as drag force on the dynamic behavior of a typical flexible structure composed of a slender cantilever beam carrying a lumped-mass on the tip. First, the system's analytical equation is obtained and solved by employing a perturbation technique. The solution process considers variations of the drag force coefficient and its effects on the system's response. Then, experimental results are presented to demonstrate the effects of the nonlinear quadratic damping due to the turbulent frictional force on the system's dynamic response. In particular, the effects of the quadratic damping on the frequency-response and amplitude-response curves are investigated. Numerically simulated as well as experimental results indicate that variations on the drag force coefficient significantly alter the dynamics of the structure under investigation. Copyright (c) 2008 D. G. Silva and P. S. Varoto.

Analysis of the tip roundness effects on the micro- and macroindentation response of elastic-plastic materials

In this work, the effects of indenter tip roundness oil the load-depth indentation curves were analyzed using finite element modeling. The tip roundness level was Studied based on the ratio between tip radius and maximum penetration depth (R/h(max)), which varied from 0.02 to 1. The proportional Curvature constant (C), the exponent of depth during loading (alpha), the initial unloading slope (S), the correction factor (beta), the level of piling-up or sinking-in (h(c)/h(max)), and the ratio h(max)/h(f) are shown to be strongly influenced by the ratio R/h(max). The hardness (H) was found to be independent of R/h(max) in the range studied. The Oliver and Pharr method was successful in following the variation of h(c)/h(max) with the ratio R/h(max) through the variation of S with the ratio R/h(max). However, this work confirmed the differences between the hardness values calculated using the Oliver-Pharr method and those obtained directly from finite element calculations; differences which derive from the error in area calculation that Occurs when given combinations of indented material properties are present. The ratio of plastic work to total work (W(p)/W(t)) was found to be independent of the ratio R/h(max), which demonstrates that the methods for the Calculation of mechanical properties based on the *indentation energy are potentially not Susceptible to errors caused by tip roundness.

Trapezoidal cross-sectional influence on FinFET threshold voltage and corner effects

Fin field effect transistors (FinFETS) are silicon-on-insulator (SOI) transistors with three-dimensional structures. As a result of some fabrication-process limitations (as nonideal anisotropic overetch) some FinFETs have inclined surfaces, which results in trapezoidal cross sections instead of rectangular sections, as expected. This geometric alteration results in some device issues, like carrier profile, threshold voltage, and corner effects. This work analyzes these consequences based on three-dimensional numeric simulation of several dual-gate and triple-gate FinFETs. The simulation results show that the threshold voltage depends on the sidewall inclination angle and that this dependence varies according to the body doping level. The corner effects also depend on the inclination angle and doping level. (C) 2008 The Electrochemical Society.

Homeotropic surface anchoring and the layer-thinning transition in free-standing films

In this work, we investigate the interplay between surface anchoring and finite-size effects on the smectic-isotropic transition in free-standing smectic films. Using an extended McMillan model, we study how a homeotropic anchoring stabilizes the smectic order above the bulk transition temperature. In particular, we determine how the transition temperature depends on the surface ordering and film thickness. We identify a characteristic anchoring for which the transition temperature does not depend on the film thickness. For strong surface ordering, we found that the thickness dependence of the transition temperature can be well represented by a power-law relation. The power-law exponent exhibits a weak dependence on the range of film thicknesses, as well as on the molecular alkyl tail length. Our results reproduce the main experimental findings concerning the layer-thinning transitions in free-standing smectic films.

EFFECTS OF THERMAL TREATMENT ON THE PHYSICOCHEMICAL CHARACTERISTICS OF GIANT BAMBOO

Despite countless use possibilities for bamboo, this material has two major disadvantages. One drawback is the low natural durability of most bamboo species due to presence of starch in their parenchyma cells. The other equally important drawback is the tendency bamboo has to present dimensional variations if subjected to environmental change conditions. In an attempt to minimize these inconveniences, strips (laths) of Dendrocalamus giganteus Munro were taken from different portions of the culm and subjected to several temperatures, namely 140 degrees C, 180 degrees C, 220 degrees C, 260 degrees C and 300 degrees C under laboratory conditions, at the ESALQ-USP college of agriculture. The thermal treatment process was conducted in noninert and inert atmospheres (with nitrogen), depending on temperature Specimens were then subjected to physicomechanical characterization tests in order to determine optimum thermal treatment conditions in which to preserve to the extent possible the original bamboo properties. Results revealed that there is an optimum temperature range, between 140 degrees and 220 degrees C, whereby thermally treated bamboo does not significantly lose its mechanical properties while at the same time showing greater dimensional stability in the presence of moisture.

Effects of enriched colostrum supply in intestinal mucosa morphology of newborn calves

Colostrum intake in neonatal calves is essential to obtain passive immunity and to influence metabolism, endocrine systems and the nutritional state. This study compares morphologic features of small intestine of calves fed a colostrum second meal at 12 hours of life with concentrations of immunoglobulin G (IgG) higher than 100mg mL(-1) (fresh colostrum or artificially prepared with addition of lyophilized colostrum) or smaller than 30mg mL(-1). Twenty-four Holstein calves were randomly grouped according to concentration of IgG intake at 12 hours of life: low (less than 30mg mL(-1)); high (more than 100mg mL(-1)); plus lyophilized colostrum (more than 120mg mL(-1)). Intestinal tissue samples were collected at 0, 10, 24 and 72 hours after birth to evaluate morphology in segments: duodenum; proximal, middle and distal jejunum and ileum by examined with a scanning electron microscope. Villi of all segments showed more organized and uniform morphology characteristics with age. Only the animals fed colostrum with more than 100mg mL(-1) of IgG at 24 hours after birth still showed the distal jejunum villi disoriented and more united in comparison to the other ages and groups. Intake of lyophilized colostrum affected ileum morphology along experiment period. Higher concentration of immunologic and bioactive elements supplied for longer period of time could be responsible for promoting effects on the enterocytes. Use of colostrum with high IgG concentrations, with or without addition of lyophilized colostrum, influenced the precocity of the intestinal mucosa development in newborn calves, suggesting earlier maturation of the mucosa.

Non-additive genetic effects on weights and performance of a Brazilian Bos taurus x Bos indicus beef composite

The aim of the present study was to evaluate the heterosis effects on weaning weight at 205 days (WW, N = 146,464), yearling weight at 390 days (YW, N = 69,315) and weight gain from weaning to yearling (WG, N = 59,307) in composite beef cattle. The fixed models were: RM, which included contemporary groups, class of age of dam, outcrossing percentages for direct and maternal effects, and additive direct and maternal ( AM) breed effects; R, RM model, minus AM breed effects, and H, RM model, minus additive breed effects. The estimates for W205 were in general positive (P < 0.01). The R and H models resulted in similar estimates, but they were very different from the ones estimated by the RM model. For W390, the R and H models resulted in general positive estimates (P < 0.05). For WG, the RM model resulted in general significant heterosis effects (P < 0.05). It can be concluded that the RM model seems to supply estimates of better quality (P < 0.01).

Effects of trans-10, cis-12 conjugated linoleic acid on gene expression and lipid metabolism of adipose tissue of growing pigs

The objective of the present study was to determine the effects of trans-10, cis-12 conjugated linoleic acid (CLA) in adipose tissue explant cultures of growing pigs on the following responses: lipogenesis (measured as rate of C-14-labeled glucose incorporation over a subsequent 2-h incubation in the presence or absence of insulin), lipolysis (release of non-esterified fatty acid over a 2-h incubation in the presence or absence of isoproterenol), activities of lipogenic enzymes, and mRNA abundance of fatty acid synthase (FAS). Adipose tissue explants from nine growing pigs (78 +/- 3 kg) were cultured in 199 medium with insulin, dexamethasone and antibiotics for 4, 12, 24, and 48 h. The treatments were 1) control: 100 mu M polyvinyl alcohol (PVA); 2) pGH: 100 ng/mL porcine growth hormone (pGH) plus 100 mu M PVA; 3) CLA200: 200 mu M trans-10, cis-12 CLA; 4) CLA50: 50 mu M trans-10, cis-12 CLA, and 5) LA: 200 mu M linoleic acid. Fatty acids were added along with PVA (2: 1), respectively, for 24 h. Explants were collected after each culture period and assayed for lipogenesis. Transcripts of FAS mRNA were quantified by real-time RT-PCR after 24 and 48 h. Lipolysis and activities of FAS, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NADP-malate dehydrogenase were determined after 48 h. As expected, glucose incorporation was decreased (P < 0.05) in response to pGH treatment (positive control). LA had no effect on any parameter evaluated. Treatment with trans-10, cis-12 CLA decreased FAS activity (P < 0.05), but NADPH-generating enzymes were unaffected by treatments. Consistent with reduction in FAS activity, both lipid synthesis and FAS mRNA abundance were reduced with chronic CLA treatment, pGH increased baseline and stimulated lipolysis (P < 0.05) after 48 h of culture, while CLA treatment had no effect on non-esterified fatty acid release. Results of this study showed that trans-10, cis-12 CLA alters lipogenesis but has no effect on lipolysis in cultures of pig adipose tissue.

Modification of composition of a nanoemulsion with different cholesteryl ester molecular species: Effects on stability, peroxidation, and cell uptake

Purpose: Use of lipid nanoemulsions as carriers of drugs for therapeutic or diagnostic purposes has been increasingly studied. Here, it was tested whether modifications of core particle constitution could affect the characteristics and biologic properties of lipid nanoemulsions. Methods: Three nanoemulsions were prepared using cholesteryl oleate, cholesteryl stearate, or cholesteryl linoleate as main core constituents. Particle size, stability, pH, peroxidation of the nanoemulsions, and cell survival and uptake by different cell lines were evaluated. Results: It was shown that cholesteryl stearate nanoemulsions had the greatest particle size and all three nanoemulsions were stable during the 237-day observation period. The pH of the three nanoemulsion preparations tended to decrease over time, but the decrease in pH of cholesteryl stearate was smaller than that of cholesteryl oleate and cholesteryl linoleate. Lipoperoxidation was greater in cholesteryl linoleate than in cholesteryl oleate and cholesteryl stearate. After four hours' incubation of human umbilical vein endothelial cells (HUVEC) with nanoemulsions, peroxidation was minimal in the presence of cholesteryl oleate and more pronounced with cholesteryl linoleate and cholesteryl stearate. In contrast, macrophage incubates showed the highest peroxidation rates with cholesteryl oleate. Cholesteryl linoleate induced the highest cell peroxidation rates, except in macrophages. Uptake of cholesteryl oleate nanoemulsion by HUVEC and fibroblasts was greater than that of cholesteryl linoleate and cholesteryl stearate. Uptake of the three nanoemulsions by monocytes was equal. Uptake of cholesteryl oleate and cholesteryl linoleate by macrophages was negligible, but macrophage uptake of cholesteryl stearate was higher. In H292 tumor cells, cholesteryl oleate showed the highest uptakes. HUVEC showed higher survival rates when incubated with cholesteryl stearate and smaller survival with cholesteryl linoleate. H292 survival was greater with cholesteryl stearate. Conclusion: Although all three nanoemulsion types were stable for a long period, considerable differences were observed in size, oxidation status, and cell survival and nanoemulsion uptake in all tested cell lines. Those differences may be helpful in protocol planning and interpretation of data from experiments with lipid nanoemulsions.