WorldWideScience

Sample records for high sleep pressure

  1. Sleep Deprivation: A Cause of High Blood Pressure?

    Science.gov (United States)

    ... it true that sleep deprivation can cause high blood pressure? Answers from Sheldon G. Sheps, M.D. Possibly. It's thought that ... hours a night could be linked to increased blood pressure. People who sleep five hours or less a ...

  2. Intraindividual Increase of Homeostatic Sleep Pressure Across Acute and Chronic Sleep Loss: A High-Density EEG Study.

    Science.gov (United States)

    Maric, Angelina; Lustenberger, Caroline; Werth, Esther; Baumann, Christian R; Poryazova, Rositsa; Huber, Reto

    2017-09-01

    To compare intraindividually the effects of acute sleep deprivation (ASD) and chronic sleep restriction (CSR) on the homeostatic increase in slow wave activity (SWA) and to relate it to impairments in basic cognitive functioning, that is, vigilance. The increase in SWA after ASD (40 hours of wakefulness) and after CSR (seven nights with time in bed restricted to 5 hours per night) relative to baseline sleep was assessed in nine healthy, male participants (age = 18-26 years) by high-density electroencephalography. The SWA increase during the initial part of sleep was compared between the two conditions of sleep loss. The increase in SWA was related to the increase in lapses of vigilance in the psychomotor vigilance task (PVT) during the preceding days. While ASD induced a stronger increase in initial SWA than CSR, the increase was globally correlated across the two conditions in most electrodes. The increase in initial SWA was positively associated with the increase in PVT lapses. The individual homeostatic response in SWA is globally preserved across acute and chronic sleep loss, that is, individuals showing a larger increase after ASD also do so after CSR and vice versa. Furthermore, the increase in SWA is globally correlated to vigilance impairments after sleep loss over both conditions. Thus, the increase in SWA might therefore provide a physiological marker for individual differences in performance impairments after sleep loss. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  3. Effects of interface pressure distribution on human sleep quality.

    Directory of Open Access Journals (Sweden)

    Zongyong Chen

    Full Text Available High sleep quality promotes efficient performance in the following day. Sleep quality is influenced by environmental factors, such as temperature, light, sound and smell. Here, we investigated whether differences in the interface pressure distribution on healthy individuals during sleep influenced sleep quality. We defined four types of pressure models by differences in the area distribution and the subjective feelings that occurred when participants slept on the mattresses. One type of model was showed "over-concentrated" distribution of pressure; one was displayed "over-evenly" distributed interface pressure while the other two models were displayed intermediate distribution of pressure. A polysomnography analysis demonstrated an increase in duration and proportion of non-rapid-eye-movement sleep stages 3 and 4, as well as decreased number of micro-arousals, in subjects sleeping on models with pressure intermediately distributed compared to models with over-concentrated or over-even distribution of pressure. Similarly, higher scores of self-reported sleep quality were obtained in subjects sleeping on the two models with intermediate pressure distribution. Thus, pressure distribution, at least to some degree, influences sleep quality and self-reported feelings of sleep-related events, though the underlying mechanisms remain unknown. The regulation of pressure models imposed by external sleep environment may be a new direction for improving sleep quality. Only an appropriate interface pressure distribution is beneficial for improving sleep quality, over-concentrated or -even distribution of pressure do not help for good sleep.

  4. Low physical activity is a determinant for elevated blood pressure in high cardiovascular risk obstructive sleep apnea.

    Science.gov (United States)

    Mendelson, Monique; Tamisier, Renaud; Laplaud, David; Dias-Domingos, Sonia; Baguet, Jean-Philippe; Moreau, Laurent; Koltes, Christian; Chavez, Léonidas; de Lamberterie, Gilles; Herengt, Frédéric; Levy, Patrick; Flore, Patrice; Pépin, Jean-Louis

    2014-08-01

    Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity, including hypertension. Beyond the severity of nocturnal hypoxia, other factors such as metabolic abnormalities but also sedentary behaviors and insufficient physical activity may contribute to elevated blood pressure (BP). To clarify the respective role of these factors as determinants of BP in OSA patients, we examined the relationship between BP and anthropometrics, severity of sleep apnea, and objectively measured physical activity and sedentary behaviors. Ninety-five adults presenting with OSA (apnea-hypopnea index > 10 events/h) and high cardiovascular risk (63.3 ± 8.8 y; body mass index: 29.9 ± 4.9 kg/m(2); apnea-hypopnea index: 41.3 ± 17.5/h; cardiovascular risk score: 13.5 ± 3.7%) were included. Physical activity and sedentary behaviors were objectively assessed by actigraphy, and self-measured home BP monitoring was measured. Logistic regression models adjusted for sex, age, and body mass index were built to identify the predictors of self-measured morning and evening BP. Physical activity was significantly related to obesity but not to the severity of sleep apnea or sleepiness. Sedentary behaviors were associated with self-measured morning and evening systolic BP (r = 0.32, P = .002; r = 0.29, P = .004). Steps per day were inversely associated with evening BP (r = -0.27, P = .01). Univariate analysis identified steps/d and time spent in vigorous physical activity as determinants for evening self-measured BP. In multivariate analysis, only steps/d were identified as a significant determinant of evening BP. Physical activity is the major determinant for evening BP in adults with OSA presenting high cardiovascular risk. Our results emphasize the need for lifestyle counseling programs in combination with CPAP to encourage regular physical activity in OSA subjects to obtain better BP control. (ClinicalTrials.gov registration NCT01226641.)

  5. Creatine supplementation reduces sleep need and homeostatic sleep pressure in rats.

    Science.gov (United States)

    Dworak, Markus; Kim, Tae; Mccarley, Robert W; Basheer, Radhika

    2017-06-01

    Sleep has been postulated to promote brain energy restoration. It is as yet unknown if increasing the energy availability within the brain reduces sleep need. The guanidine amino acid creatine (Cr) is a well-known energy booster in cellular energy homeostasis. Oral Cr-monohydrate supplementation (CS) increases exercise performance and has been shown to have substantial effects on cognitive performance, neuroprotection and circadian rhythms. The effect of CS on cellular high-energy molecules and sleep-wake behaviour is unclear. Here, we examined the sleep-wake behaviour and brain energy metabolism before and after 4-week-long oral administration of CS in the rat. CS decreased total sleep time and non-rapid eye movement (NREM) sleep significantly during the light (inactive) but not during the dark (active) period. NREM sleep and NREM delta activity were decreased significantly in CS rats after 6 h of sleep deprivation. Biochemical analysis of brain energy metabolites showed a tendency to increase in phosphocreatine after CS, while cellular adenosine triphosphate (ATP) level decreased. Microdialysis analysis showed that the sleep deprivation-induced increase in extracellular adenosine was attenuated after CS. These results suggest that CS reduces sleep need and homeostatic sleep pressure in rats, thereby indicating its potential in the treatment of sleep-related disorders. © 2017 European Sleep Research Society.

  6. Sleep in High Stress Occupations

    Science.gov (United States)

    Flynn-Evans, Erin

    2014-01-01

    High stress occupations are associated with sleep restriction, circadian misalignment and demanding workload. This presentation will provide an overview of sleep duration, circadian misalignment and fatigue countermeasures and performance outcomes during spaceflight and commercial aviation.

  7. Association between sleep duration and blood pressure in adolescents.

    Science.gov (United States)

    Paciência, Inês; Barros, Henrique; Araújo, Joana; Ramos, Elisabete

    2013-08-01

    In adults, sleep has an important role in the development of cardiovascular diseases. However, in young adolescents, the effect is unclear. The purpose of this cross-sectional study was to evaluate the association between sleep duration and blood pressure (BP) in subjects of 13 years of age. We evaluated 1771 adolescents as part of a population-based cohort (Epidemiological Health Investigation of Teenagers). Sleep duration was estimated based on the difference between self-reported usual bedtimes and wake-up times, and adolescents were classified into three categories: 8.5 h (reference class), >8.5 h and sleep duration, the odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed by fitting binary logistic regression models with adjustments for caffeine intake and depressive symptoms in females and for caffeine intake and sports activities in males. The mean (s.d.) sleep duration was 9.0 (0.80) h per day. The prevalence of high BP was 32.5%, higher in males (35.3%) than in females (30.1%, P=0.019). After adjustment, in females, a positive association was found between sleep duration and high BP (>8.5 and sleep duration and BP. Sleep duration was positively associated with BP in both sexes, although after adjustment for potential confounders, this association was significant only for female adolescents.

  8. Benefits of Sleep Extension on Sustained Attention and Sleep Pressure Before and During Total Sleep Deprivation and Recovery.

    Science.gov (United States)

    Arnal, Pierrick J; Sauvet, Fabien; Leger, Damien; van Beers, Pascal; Bayon, Virginie; Bougard, Clément; Rabat, Arnaud; Millet, Guillaume Y; Chennaoui, Mounir

    2015-12-01

    To investigate the effects of 6 nights of sleep extension on sustained attention and sleep pressure before and during total sleep deprivation and after a subsequent recovery sleep. Subjects participated in two experimental conditions (randomized cross-over design): extended sleep (EXT, 9.8 ± 0.1 h (mean ± SE) time in bed) and habitual sleep (HAB, 8.2 ± 0.1 h time in bed). In each condition, subjects performed two consecutive phases: (1) 6 nights of either EXT or HAB (2) three days in-laboratory: baseline, total sleep deprivation and after 10 h of recovery sleep. Residential sleep extension and sleep performance laboratory (continuous polysomnographic recording). 14 healthy men (age range: 26-37 years). EXT vs. HAB sleep durations prior to total sleep deprivation. Total sleep time and duration of all sleep stages during the 6 nights were significantly higher in EXT than HAB. EXT improved psychomotor vigilance task performance (PVT, both fewer lapses and faster speed) and reduced sleep pressure as evidenced by longer multiple sleep latencies (MSLT) at baseline compared to HAB. EXT limited PVT lapses and the number of involuntary microsleeps during total sleep deprivation. Differences in PVT lapses and speed and MSLT at baseline were maintained after one night of recovery sleep. Six nights of extended sleep improve sustained attention and reduce sleep pressure. Sleep extension also protects against psychomotor vigilance task lapses and microsleep degradation during total sleep deprivation. These beneficial effects persist after one night of recovery sleep. © 2015 Associated Professional Sleep Societies, LLC.

  9. [The association between blood pressure variability and sleep stability in essential hypertensive patients with sleep disorder].

    Science.gov (United States)

    Zhu, Y Q; Long, Q; Xiao, Q F; Zhang, M; Wei, Y L; Jiang, H; Tang, B

    2018-03-13

    Objective: To investigate the association of blood pressure variability and sleep stability in essential hypertensive patients with sleep disorder by cardiopulmonary coupling. Methods: Performed according to strict inclusion and exclusion criteria, 88 new cases of essential hypertension who came from the international department and the cardiology department of china-japan friendship hospital were enrolled. Sleep stability and 24 h ambulatory blood pressure data were collected by the portable sleep monitor based on cardiopulmonary coupling technique and 24 h ambulatory blood pressure monitor. Analysis the correlation of blood pressure variability and sleep stability. Results: In the nighttime, systolic blood pressure standard deviation, systolic blood pressure variation coefficient, the ratio of the systolic blood pressure minimum to the maximum, diastolic blood pressure standard deviation, diastolic blood pressure variation coefficient were positively correlated with unstable sleep duration ( r =0.185, 0.24, 0.237, 0.43, 0.276, P Blood pressure variability is associated with sleep stability, especially at night, the longer the unstable sleep duration, the greater the variability in night blood pressure.

  10. Recruitment Strategies and Costs Associated With Enrolling People With Insomnia and High Blood Pressure Into an Online Behavioral Sleep Intervention: A Single-Site Pilot Study.

    Science.gov (United States)

    Routledge, Faye S; Davis, Tara D; Dunbar, Sandra B

    Recruitment in clinical research is a common challenge and source of study failure. The reporting of recruitment methods and costs in hypertension trials is limited especially for smaller, single-site trials, online intervention trials, and trials using newer online recruitment strategies. The aims of this study are to describe and examine the feasibility of newer online-e-mail recruitment strategies and traditional recruitment strategies used to enroll participants with insomnia and high blood pressure into an online behavioral sleep intervention study (Sleeping for Heart Health). The 16 online-e-mail-based and traditional recruitment strategies used are described. Recruitment strategy feasibility was examined by study interest and enrollee yields, conversion rates, and costs (direct, remuneration, labor, and cost per enrollee). From August 2014 to October 2015, 183 people were screened and 58 (31.7%) enrolled in the study (51.1 ± 12.9 years, 63.8% female, 72.4% African American, 136 ± 12/88 ± 7 mm Hg, 87.9% self-reported hypertension, 67.2% self-reported antihypertensive medication use). The recruitment strategies yielding the highest enrollees were the university hospital phone waiting message system (25.4%), Craigslist (22.4%), and flyers (20.3%) at a per enrollee cost of $42.84, $98.90, and $128.27, respectively. The university hospital phone waiting message system (55.6%) and flyers (54.5%) had the highest interested participant to enrolled participant conversion rate of all recruitment strategies. Approximately 70% of all enrolled participants were recruited from the university hospital phone waiting message system, Craigslist, or flyers. Given the recruitment challenges that most researchers face, we encourage the documenting, assessing, and reporting of detailed recruitment strategies and associated recruitment costs so that other researchers may benefit.

  11. Pediatric sleep apnea

    Science.gov (United States)

    Sleep apnea - pediatric; Apnea - pediatric sleep apnea syndrome; Sleep-disordered breathing - pediatric ... Untreated pediatric sleep apnea may lead to: High blood pressure Heart or lung problems Slow growth and development

  12. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  13. High Blood Pressure Facts

    Science.gov (United States)

    ... Stroke Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir On ... Top of Page CDC Fact Sheets Related to High Blood Pressure High Blood Pressure Pulmonary Hypertension Heart Disease Signs ...

  14. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  15. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Teens / Hypertension (High Blood Pressure) What's ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  16. High blood pressure - children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007696.htm High blood pressure - children To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  17. Preventing High Blood Pressure

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

  18. High blood pressure - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007329.htm High blood pressure - infants To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  19. High blood pressure medications

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

  20. High-pressure microbiology

    National Research Council Canada - National Science Library

    Michiels, Chris; Bartlett, Douglas Hoyt; Aertsen, Abram

    2008-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. High Hydrostatic Pressure Effects in the Biosphere: from Molecules to Microbiology * Filip Meersman and Karel Heremans . . . . . . . . . . . . 2. Effects...

  1. High-pressure apparatus

    NARCIS (Netherlands)

    Schepdael, van L.J.M.; Bartels, P.V.; Berg, van den R.W.

    1999-01-01

    The invention relates to a high-pressure device (1) having a cylindrical high-pressure vessel (3) and prestressing means in order to exert an axial pressure on the vessel. The vessel (3) can have been formed from a number of layers of composite material, such as glass, carbon or aramide fibers which

  2. High blood pressure - adults

    Science.gov (United States)

    ... pressure is found. This is called essential hypertension. High blood pressure that is caused by another medical condition or medicine you are taking is called secondary hypertension. Secondary hypertension may be due to: Chronic ...

  3. Noninvasive Positive Pressure Ventilatory Support Begins During Sleep.

    Science.gov (United States)

    Bach, John R

    2017-12-01

    The goal of sleep doctors has been to titrate away apneas and hypopneas using noninvasive ventilation, a term that has become synonymous with continuous positive airway pressure and bilevel positive airway pressure at the lowest effective bilevel settings. It is now time to appreciate noninvasive ventilatory support as an alternative to invasive mechanical ventilation. This article discusses mechanisms of action, two paradigms, and ancillary techniques for noninvasive ventilatory support. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Sleep Insufficiency, Sleep Health Problems and Performance in High School Students

    OpenAIRE

    Ming, Xue; Koransky, Rebecca; Kang, Victor; Buchman, Sarah; Sarris, Christina E.; Wagner, George C.

    2011-01-01

    A survey on sleep schedule, sleep health, school performance and school start times was conducted in 1,941 adolescents. A high level of early and circadian-disadvantaged sleep/wake schedules during weekdays was observed. Shorter sleep duration on weekdays was reported, especially in upper classmen. Complaints of inadequate sleep and sleepiness during weekdays, alarm clock use, and napping were prevalent. Night awakening and prolonged sleep onset were common and associated with poor school per...

  5. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... other risk factors, like diabetes, you may need treatment. How does high blood pressure affect pregnant women? A few women will get ... HIV, Birth Control Heart Health for Women Pregnancy Menopause More Women's Health ... High Blood Pressure--Medicines to Help You Women and Diabetes Heart ...

  6. High-pressure crystallography

    Science.gov (United States)

    Katrusiak, A.

    2008-01-01

    The history and development of high-pressure crystallography are briefly described and examples of structural transformations in compressed compounds are given. The review is focused on the diamond-anvil cell, celebrating its 50th anniversary this year, the principles of its operation and the impact it has had on high-pressure X-ray diffraction.

  7. High Blood Pressure

    Science.gov (United States)

    ... kidney disease, diabetes, or metabolic syndrome Read less Unhealthy lifestyle habits Unhealthy lifestyle habits can increase the risk of high blood pressure. These habits include: Unhealthy eating patterns, such as eating too much sodium ...

  8. High Blood Pressure

    Science.gov (United States)

    ... factors Diabetes High blood pressure Family history Obesity Race/ethnicity Full list of causes and risk factors ... give Give monthly Memorials and tributes Donate a car Donate gently used items Stock donation Workplace giving ...

  9. High-pressure tritium

    International Nuclear Information System (INIS)

    Coffin, D.O.

    1976-01-01

    Some solutions to problems of compressing and containing tritium gas to 200 MPa at 700 0 K are discussed. The principal emphasis is on commercial compressors and high-pressure equipment that can be easily modified by the researcher for safe use with tritium. Experience with metal bellows and diaphragm compressors has been favorable. Selection of materials, fittings, and gauges for high-pressure tritium work is also reviewed briefly

  10. Sleep Insufficiency, Sleep Health Problems and Performance in High School Students

    Directory of Open Access Journals (Sweden)

    Xue Ming

    2011-01-01

    Full Text Available A survey on sleep schedule, sleep health, school performance and school start times was conducted in 1,941 adolescents. A high level of early and circadian-disadvantaged sleep/wake schedules during weekdays was observed. Shorter sleep duration on weekdays was reported, especially in upper classmen. Complaints of inadequate sleep and sleepiness during weekdays, alarm clock use, and napping were prevalent. Night awakening and prolonged sleep onset were common and associated with poor school performance. Students with a sleep length of less than 7 hours on both weekdays and weekends exhibited poorer performance, while those who made up this sleep loss on weekends did not. The total number of poor sleep factors in an individual also correlated with poor school performance. Earlier school start times were associated with a perception of poor sleep quality, shorter sleep duration and more sleep health problems. We conclude that sleep inadequacies and sleep health problems were prevalent in this population, especially in those who started school earlier in the morning, and that these poor sleep factors were associated with school performance.

  11. Deuterium high pressure target

    International Nuclear Information System (INIS)

    Perevozchikov, V.V.; Yukhimchuk, A.A.; Vinogradov, Yu.I.

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm 3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  12. Sleep deprivation increases blood pressure in healthy normotensive elderly and attenuates the blood pressure response to orthostatic challenge.

    Science.gov (United States)

    Robillard, Rébecca; Lanfranchi, Paola A; Prince, François; Filipini, Daniel; Carrier, Julie

    2011-03-01

    To determine how aging affects the impact of sleep deprivation on blood pressure at rest and under orthostatic challenge. Subjects underwent a night of sleep and 24.5 h of sleep deprivation in a crossover counterbalanced design. Sleep laboratory. Sixteen healthy normotensive men and women: 8 young adults (mean 24 years [SD 3.1], range 20-28 years) and 8 elderly adults (mean 64.1 years [SD 3.4], range 60-69 years). Sleep deprivation. Brachial cuff arterial blood pressure and heart rate were measured in semi-recumbent and upright positions. These measurements were compared across homeostatic sleep pressure conditions and age groups. Sleep deprivation induced a significant increase in systolic and diastolic blood pressure in elderly but not young adults. Moreover, sleep deprivation attenuated the systolic blood pressure orthostatic response in both age groups. Our results suggest that sleep deprivation alters the regulatory mechanisms of blood pressure and might increase the risk of hypertension in healthy normotensive elderly.

  13. High Pressure Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pradeep K [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2016-07-29

    According to the Billion Ton Report, the U.S. has a large supply of biomass available that can supplement fossil fuels for producing chemicals and transportation fuels. Agricultural waste, forest residue, and energy crops offer potential benefits: renewable feedstock, zero to low CO2 emissions depending on the specific source, and domestic supply availability. Biomass can be converted into chemicals and fuels using one of several approaches: (i) biological platform converts corn into ethanol by using depolymerization of cellulose to form sugars followed by fermentation, (ii) low-temperature pyrolysis to obtain bio-oils which must be treated to reduce oxygen content via HDO hydrodeoxygenation), and (iii) high temperature pyrolysis to produce syngas (CO + H2). This last approach consists of producing syngas using the thermal platform which can be used to produce a variety of chemicals and fuels. The goal of this project was to develop an improved understanding of the gasification of biomass at high pressure conditions and how various gasification parameters might affect the gasification behavior. Since most downstream applications of synags conversion (e.g., alcohol synthesis, Fischer-Tropsch synthesis etc) involve utilizing high pressure catalytic processes, there is an interest in carrying out the biomass gasification at high pressure which can potentially reduce the gasifier size and subsequent downstream cleaning processes. It is traditionally accepted that high pressure should increase the gasification rates (kinetic effect). There is also precedence from coal gasification literature from the 1970s that high pressure gasification would be a beneficial route to consider. Traditional approach of using thermogravimetric analyzer (TGA) or high-pressure themogravimetric analyzer (PTGA) worked well in understanding the gasification kinetics of coal gasification which was useful in designing high pressure coal gasification processes. However

  14. Fascination at high pressures

    International Nuclear Information System (INIS)

    Chidambaram, R.

    1992-01-01

    Research at high pressures has developed into an interdisciplinary area which has important implications for and applications in the areas of physics, chemistry, materials sciences, planetary sciences, biology, engineering sciences and technology. The state of-the-art in this field is reviewed and future directions are indicated. (M.G.B.)

  15. Sleep disorders among high school students in New Zealand

    OpenAIRE

    Fernando AT; Samaranayake CB; Blank CJ; Roberts G; Arroll B

    2013-01-01

    INTRODUCTION: Adolescents are known to have high risk factors for sleep disorders, yet the youth rates of sleep disturbances are unknown. AIM: This study aimed to determine the prevalence of sleep disorders among New Zealand high school students. METHODS: The Auckland Sleep Questionnaire (ASQ) was administered to high school students at six schools in the North Island. Schools were chosen to reflect a range of ethnicities and school deciles, which identify the socioeconomic status of househol...

  16. Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation

    Directory of Open Access Journals (Sweden)

    Micheline eMaire

    2014-03-01

    Full Text Available Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e. state instability in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3. By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER35/5 experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER34/4. These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioural vulnerability.

  17. Flextube reflectometry and pressure recordings for level diagnosis in obstructive sleep apnoea

    DEFF Research Database (Denmark)

    Faber, C E; Grymer, L; Hilberg, O

    2002-01-01

    The objective of this study was to compare sound reflections in a flexible tube (flextube reflectometry) with pressure-catheter recordings (ApneaGraph) for identifying the predominant obstructive level of the upper airway during sleep. Seventeen males with suspected obstructive sleep apnoea...... results were found in flextube reflectometry studies and pressure-recordings performed on different nights regarding the level distribution of obstructions during sleep. Possible explanations of this discrepancy are discussed....

  18. Sleep Sleeping Patch

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Sleep Sleeping Patch is a new kind of external patch based on modern sleep medicine research achievements, which uses the internationally advanced transdermal therapeutic system (TTS). The Sleep Sleeping Patch transmits natural sleep inducers such as peppermint and liquorice extracts and melatonin through the skin to induce sleep. Clinical research proves that the Sleep Sleeping Patch can effectively improve insomnia and the quality of sleep. Highly effective: With the modern TTS therapy,

  19. Proportional positive airway pressure: a new concept to treat obstructive sleep apnoea.

    Science.gov (United States)

    Juhász, J; Becker, H; Cassel, W; Rostig, S; Peter, J H

    2001-03-01

    Proportional positive airway pressure (PPAP) was designed to optimize airway pressure for the therapy of obstructive sleep apnoea (OSA). In a randomized crossover prospective study, the clinical feasibility of PPAP and its immediate effects on the breathing disorder and sleep in comparison with continuous positive airway pressure (CPAP) was evaluated. Twelve patients requiring CPAP therapy underwent CPAP and PPAP titration in a random order. Obstructive and mixed respiratory events could be completely abolished with both forms of treatment. This efficacy could be achieved at a significantly lower mean mask pressure during PPAP titration (8.45+/-2.42 cmH2O) compared to CPAP (9.96+/-2.7 cmH2O) (p=0.002). The mean minimal arterial oxygen saturation (Sa,O2) (82.8+/-6.5%) on the diagnostic night increased significantly (pPPAP titration. Total sleep time, slow wave sleep and rapid eye movement (REM) sleep increased significantly by the same amount during both CPAP and PPAP titration (pPPAP titration night, four patients did not have a preference, and two patients preferred CPAP. The present data show that proportional positive airway pressure is as effective as continuous positive airway pressure in eliminating obstructive events and has the same immediate effect on sleep. The lower average mask pressure during proportional positive airway pressure implies potential advantages compared to continuous positive airway pressure. Proportional positive airway pressure presents a new effective therapeutic approach to obstructive sleep apnoea.

  20. Cryogenic, Absolute, High Pressure Sensor

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  1. Cryogenic High Pressure Sensor Module

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

    1999-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  2. Influence of sleep apnea severity on blood pressure variability of patients with hypertension.

    Science.gov (United States)

    Steinhorst, Ana P; Gonçalves, Sandro C; Oliveira, Ana T; Massierer, Daniela; Gus, Miguel; Fuchs, Sandra C; Moreira, Leila B; Martinez, Denis; Fuchs, Flávio D

    2014-05-01

    Obstructive sleep apnea (OSA) is a risk factor for the development of hypertension and cardiovascular disease. Apnea overloads the autonomic cardiovascular control system and may influence blood pressure variability, a risk for vascular damage independent of blood pressure levels. This study investigates the hypothesis that blood pressure variability is associated with OSA. In a cross-sectional study, 107 patients with hypertension underwent 24-h ambulatory blood pressure monitoring and level III polysomnography to detect sleep apnea. Pressure variability was assessed by the first derivative of blood pressure over time, the time rate index, and by the standard deviation of blood pressure measurements. The association between the apnea-hypopnea index and blood pressure variability was tested by univariate and multivariate methods. The 57 patients with apnea were older, had higher blood pressure, and had longer duration of hypertension than the 50 patients without apnea. Patients with apnea-hypopnea index (AHI) ≥ 10 had higher blood pressure variability assessed by the standard deviation than patients with AHI variability assessed by the time rate index presented a trend for association during sleep (P = 0.07). Daytime blood pressure variability was not associated with the severity of sleep apnea. Sleep apnea increases nighttime blood pressure variability in patients with hypertension and may be another pathway linking sleep abnormalities to cardiovascular disease.

  3. Can High Altitude Influence Cytokines and Sleep?

    Directory of Open Access Journals (Sweden)

    Valdir de Aquino Lemos

    2013-01-01

    Full Text Available The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2 induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β, Interleukin-6 (IL-6, and tumor necrosis factor-alpha (TNF-α production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain.

  4. Can High Altitude Influence Cytokines and Sleep?

    Science.gov (United States)

    de Aquino Lemos, Valdir; dos Santos, Ronaldo Vagner Thomatieli; Lira, Fabio Santos; Rodrigues, Bruno; Tufik, Sergio; de Mello, Marco Tulio

    2013-01-01

    The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2) induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain. PMID:23690660

  5. Pressure Dome for High-Pressure Electrolyzer

    Science.gov (United States)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

  6. Is the Relationship between Race and Continuous Positive Airway Pressure Adherence Mediated by Sleep Duration?

    Science.gov (United States)

    Billings, Martha E.; Rosen, Carol L.; Wang, Rui; Auckley, Dennis; Benca, Ruth; Foldvary-Schaefer, Nancy; Iber, Conrad; Zee, Phyllis; Redline, Susan; Kapur, Vishesh K.

    2013-01-01

    Study Objectives: Black race has been associated with decreased continuous positive airway pressure (CPAP) adherence. Short sleep duration, long sleep latency, and insomnia complaints may affect CPAP adherence as they affect sleep and opportunity to use CPAP. We assessed whether self-reported sleep measures were associated with CPAP adherence and if racial variations in these sleep characteristics may explain racial differences in CPAP adherence. Design: Analysis of data from a randomized controlled trial (HomePAP), which investigated home versus laboratory-based diagnosis and treatment of obstructive sleep apnea. Setting: Seven American Academy of Sleep Medicine-accredited sleep centers in five cities in the United States. Patients or Participants: Enrolled subjects (n = 191) with apnea-hypopnea index ≥ 15 and sleepiness (Epworth Sleepiness Scale > 12). Interventions: N/A. Measurements and Results: Multivariable regression was used to assess if subjective sleep measures and symptoms predicted 3-mo CPAP use. Mediation analysis was used to assess if sleep measures mediated the association of race with CPAP adherence. Black participants reported shorter sleep duration and longer sleep latency at baseline than white and Hispanic participants. Shorter sleep duration and longer sleep latency predicted worse CPAP adherence. Sleep duration mediated the association of black race with lower CPAP adherence. However, insomnia symptoms were not associated with race or CPAP adherence. Conclusions: Among subjects with similar severity of obstructive sleep apnea and sleepiness, baseline self-reported sleep duration and latency, but not perceived insomnia, predicted CPAP adherence over 3 mo. Sleep duration explains some of the observed differences in CPAP use by race. Sleep duration and latency should be considered when evaluating poor CPAP adherence. Clinical Trial Information: Portable Monitoring for Diagnosis and Management of Sleep Apnea (HomePAP) URL: http

  7. Automatic limb identification and sleeping parameters assessment for pressure ulcer prevention.

    Science.gov (United States)

    Baran Pouyan, Maziyar; Birjandtalab, Javad; Nourani, Mehrdad; Matthew Pompeo, M D

    2016-08-01

    Pressure ulcers (PUs) are common among vulnerable patients such as elderly, bedridden and diabetic. PUs are very painful for patients and costly for hospitals and nursing homes. Assessment of sleeping parameters on at-risk limbs is critical for ulcer prevention. An effective assessment depends on automatic identification and tracking of at-risk limbs. An accurate limb identification can be used to analyze the pressure distribution and assess risk for each limb. In this paper, we propose a graph-based clustering approach to extract the body limbs from the pressure data collected by a commercial pressure map system. A robust signature-based technique is employed to automatically label each limb. Finally, an assessment technique is applied to evaluate the experienced stress by each limb over time. The experimental results indicate high performance and more than 94% average accuracy of the proposed approach. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Primate body temperature and sleep responses to lower body positive pressure

    Science.gov (United States)

    Edgar, D. M.; Fuller, C. A.

    1984-01-01

    Cephalic fluid shifts, induced by lower body positive pressure (LBPP) are known to influence various physiological systems (i.e., cardiovascular and renal). In earlier experiments, an apparent change in the arousal state of primates in such LBPP conditions was observed. This study was designed to examine the effects of LBPP on arousal state and body temperature level which is normally correlated with sleep. Chair-restrained male squirrel monkeys were exposed to 40 mmHg LBPP for 90-100 minutes between the daytime hours of 13:00-15:00. Each monkey was placed in a specially modified restraint chair to which they were highly trained. Deep body temperature (DBT) was collected from 10 animals. Sleep parameters were obtained from six animals chronically implanted for sleep recording. A video camera was used to observe each animal's apparent state of arousal. LBPP resulted in an approximate 0.9 C decrease in DBT. During video observation, some animals appeared drowsy during LBPP; however, sleep recording revealed no significant changes in the state of arousal. Thus, LBPP is capable of inducing a mild hyperthermia. Further, the mechanisms underlying the observed lowering of body temperature appear to be independent of arousal state.

  9. Sleep disorders among high school students in New Zealand.

    Science.gov (United States)

    Fernando, Antonio T; Samaranayake, Chinthaka B; Blank, Christopher J; Roberts, Gareth; Arroll, Bruce

    2013-12-01

    Adolescents are known to have high risk factors for sleep disorders, yet the youth rates of sleep disturbances are unknown. This study aimed to determine the prevalence of sleep disorders among New Zealand high school students. The Auckland Sleep Questionnaire (ASQ) was administered to high school students at six schools in the North Island. Schools were chosen to reflect a range of ethnicities and school deciles, which identify the socioeconomic status of households in the school catchment area. A total of 1388 students completed the ASQ. The median age was 17 years (range 14-23) and females represented 43.5% (n=604) of the total group. A total of 37.2% of the students surveyed reported having significant sleep symptoms lasting longer than one month. Depression and anxiety were present in 51.7% and 44.8% of students reporting a sleep problem, respectively. A moderate correlation was observed between sleep problems and depression (r=0.34, psleep problems and anxiety (r=0.31, pstudents with sleep symptoms (12.2% and 5.5% respectively). No difference was found in the rate of sleep problems reported by different ethnic groups. A considerable proportion of students surveyed reported significant sleep symptoms. This study has the potential to aid physicians within New Zealand in better appreciating the burden of sleep disorders faced by young people and in effectively assessing and managing different causes of sleep symptoms in this demographic.

  10. Functional role of diverse changes in sympathetic nerve activity in regulating arterial pressure during REM sleep.

    Science.gov (United States)

    Yoshimoto, Misa; Yoshida, Ikue; Miki, Kenju

    2011-08-01

    This study aimed to investigate whether REM sleep evoked diverse changes in sympathetic outflows and, if so, to elucidate why REM sleep evokes diverse changes in sympathetic outflows. Male Wistar rats were chronically implanted with electrodes to measure renal (RSNA) and lumbar sympathetic nerve activity (LSNA), electroencephalogram, electromyogram, and electrocardiogram, and catheters to measure systemic arterial and central venous pressure; these parameters were measured simultaneously and continuously during the sleep-awake cycle in the same rat. REM sleep resulted in a step reduction in RNSA by 36.1% ± 2.7% (P sleep. In contrast to REM sleep, RSNA, LSNA, systemic arterial pressure, and heart rate increased in a unidirectional manner associated with increases in physical activity levels in the order from NREM sleep, quiet awake, moving, and grooming state. Thus, the relationship between RSNA vs. LSNA and systemic arterial pressure vs. heart rate observed during REM sleep was dissociated compared with that obtained during the other behavioral states. It is suggested that the diverse changes in sympathetic outflows during REM sleep may be needed to increase systemic arterial pressure by balancing vascular resistance between muscles and vegetative organs without depending on the heart.

  11. Sleep homeostatic pressure and PER3 VNTR gene polymorphism influence antidepressant response to sleep deprivation in bipolar depression.

    Science.gov (United States)

    Dallaspezia, Sara; Locatelli, Clara; Lorenzi, Cristina; Pirovano, Adele; Colombo, Cristina; Benedetti, Francesco

    2016-03-01

    Combined Total sleep deprivation (TSD) and light therapy (LT) cause a rapid improvement in bipolar depression which has been hypothesized to be paralleled by changes in sleep homeostasis. Recent studies showed that bipolar patients had lower changes of EEG theta power after sleep and responders to antidepressant TSD+LT slept less and showed a lower increase of EEG theta power then non-responders. A polymorphism in PER3 gene has been associated with diurnal preference, sleep structure and homeostatic response to sleep deprivation in healthy subjects. We hypothesized that the individual variability in the homeostatic response to TSD could be a correlate of antidepressant response and be influenced by genetic factors. We administered three TSD+LT cycles to bipolar depressed patients. Severity of depression was rated on Hamilton Depression Rating Scale. Actigraphic recordings were performed in a group of patients. PER3 polymorphism influenced changes in total sleep time (F=2.24; p=0.024): while PER3(4/4) and PER3(4/5) patients showed a reduction in it after treatment, PER3(5/5) subjects showed an increase of about 40min, suggesting a higher homeostatic pressure. The same polymorphism influenced the change of depressive symptomatology during treatment (F=3.72; p=0.028). Sleep information was recorded till the day after the end of treatment: a longer period of observation could give more information about the possible maintenance of allostatic adaptation. A higher sleep homeostatic pressure reduced the antidepressant response to TSD+LT, while an allostatic adaptation to sleep loss was associated with better response. This process seems to be under genetic control. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Clinical predictors of central sleep apnea evoked by positive airway pressure titration

    OpenAIRE

    Bianchi, Matt; Gannon,Karen; Lovell,Kathy; Merlino,Margaret; Mojica,James; Moro,Marilyn

    2016-01-01

    Marilyn Moro,1 Karen Gannon,1 Kathy Lovell,1 Margaret Merlino,1 James Mojica,2 Matt T Bianchi,1,3 1Neurology Department, 2Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA; 3Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA Purpose: Treatment-emergent central sleep apnea (TECSA), also called complex apnea, occurs in 5%–15% of sleep apnea patients during positive airway pressure (PAP) therapy, but the clinical predictors are not w...

  13. Sleep architecture, insulin resistance and the nasal cycle: Implications for positive airway pressure therapy

    Directory of Open Access Journals (Sweden)

    Catherine A.P. Crofts

    2018-03-01

    Full Text Available Background: The global pandemic of metabolic disease is worsening. The metabolic theory of obesity proposes that hormonal changes, especially hyperinsulinaemia, precede metabolic disease development. Although quality sleep is recognised as a key factor for good health, less is known about disrupted sleep as a risk factor for hyperinsulinaemia.   Aim: To explore the relationship between sleep, especially sleep architecture and the nasal cycle, on insulin secretion in obstructive sleep apnoea (OSA with comorbid metabolic disease. This review includes a discussion of the potential role of Rest-Activity-Cycler positive airway pressure (RACer-PAP, a novel non-pharmacological OSA treatment strategy.   Methods: A narrative review of all the relevant papers known to the authors was conducted. This review also included results from a polysomnographic sleep clinic pilot study (n = 3 comparing sleep efficiency of RACer-PAP to nasal continuous positive airways pressure (n-CPAP in OSA patients.   Results: Metabolic disease is strongly associated with disturbed sleep. Sleep architecture influences cerebral hormonal secretion, lateral shifts in the autonomic nervous system and nasal airflow dominance. Disturbed sleep shortens short-wave sleep periods, decreasing insulin sensitivity and glucose tolerance. Improvements to metabolic function during n-CPAP treatment are inconsistent. If RACer-PAP demonstrates superior effects on sleep architecture and autonomic function, it may offer advantages in OSA patients with comorbid metabolic disease.   Conclusion: Improving sleep architecture by maintaining the nasal cycle proposes a novel non-pharmacological treatment paradigm for treating OSA with comorbid metabolic disease. Research is required to demonstrate if RACer-PAP therapy influences whole night sleep architecture, sympathovagal balance and markers of metabolic disease.

  14. High pressure mechanical seal

    Science.gov (United States)

    Babel, Henry W. (Inventor); Anderson, Raymond H. (Inventor)

    1996-01-01

    A relatively impervious mechanical seal is formed between the outer surface of a tube and the inside surface of a mechanical fitting of a high pressure fluid or hydraulic system by applying a very thin soft metal layer onto the outer surface of the hard metal tube and/or inner surface of the hard metal fitting. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After compression, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as measured using the Helium leak test.

  15. Common High Blood Pressure Myths

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More Common High Blood Pressure Myths Updated:May 4,2018 Knowing the facts ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  16. Medications for High Blood Pressure

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Medications for High Blood Pressure Share Tweet Linkedin Pin it More sharing options ... age and you cannot tell if you have high blood pressure by the way you feel, so have your ...

  17. High blood pressure and diet

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007483.htm High blood pressure and diet To use the sharing features on ... diet is a proven way to help control high blood pressure . These changes can also help you lose weight ...

  18. Controlling your high blood pressure

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000101.htm Controlling your high blood pressure To use the sharing features on this page, ... JavaScript. Hypertension is another term used to describe high blood pressure. High blood pressure can lead to: Stroke Heart ...

  19. Beneficial Effects of Long-Term CPAP Treatment on Sleep Quality and Blood Pressure in Adherent Subjects With Obstructive Sleep Apnea.

    Science.gov (United States)

    Yang, Mei-Chen; Huang, Yi-Chih; Lan, Chou-Chin; Wu, Yao-Kuang; Huang, Kuo-Feng

    2015-12-01

    Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular diseases. Although CPAP is the first treatment choice for moderate-to-severe OSA, acceptance of and adherence to CPAP remain problematic. High CPAP adherence is generally defined as ≥4 h of use/night for ≥70% of the nights monitored. We investigated the long-term beneficial effects of CPAP on sleep quality and blood pressure in subjects with moderate-to-severe OSA according to high or low CPAP adherence. We retrospectively analyzed 121 subjects with moderate-to-severe OSA from August 2008 to July 2012. These subjects were divided into 3 groups: (1) no CPAP treatment (n = 29), (2) low CPAP adherence (n = 28), and (3) high CPAP adherence (n = 64). All subjects were followed up for at least 1 y. The 3 groups were compared regarding anthropometric and polysomnographic variables, presence of cardiovascular comorbidities, and blood pressure at baseline and at the last follow-up. The no-treatment group showed significant increases in oxygen desaturation index and blood pressure. The high-adherence group showed significant improvement in daytime sleepiness, apnea-hypopnea index (AHI), oxygen desaturation index, and blood pressure. Although the AHI was also significantly decreased after CPAP treatment in the low-adherence group, blood pressure remained unchanged. CPAP treatment had beneficial effects on both sleep quality and blood pressure only in subjects with OSA and high CPAP adherence who used CPAP for ≥4 h/night for ≥70% of nights monitored. Subjects with low CPAP adherence received beneficial effects on AHI, but not blood pressure. Copyright © 2015 by Daedalus Enterprises.

  20. Insomnia complaints in lean patients with obstructive sleep apnea negatively affect positive airway pressure treatment adherence.

    Science.gov (United States)

    Eysteinsdottir, Bjorg; Gislason, Thorarinn; Pack, Allan I; Benediktsdottir, Bryndís; Arnardottir, Erna S; Kuna, Samuel T; Björnsdottir, Erla

    2017-04-01

    The objective of this study was to evaluate the determinants of long-term adherence to positive airway pressure treatment among patients with obstructive sleep apnea, with special emphasis on patients who stop positive airway pressure treatment within 1 year. This is a prospective long-term follow-up of subjects in the Icelandic Sleep Apnea Cohort who were diagnosed with obstructive sleep apnea between 2005 and 2009, and started on positive airway pressure treatment. In October 2014, positive airway pressure adherence was obtained by systematically evaluating available clinical files (n = 796; 644 males, 152 females) with moderate to severe obstructive sleep apnea (apnea-hypopnea index ≥15 events per h). The mean follow-up time was 6.7 ± 1.2 years. In total, 123 subjects (15.5%) returned their positive airway pressure device within the first year, 170 (21.4%) returned it later and 503 (63.2%) were still using positive airway pressure. The quitters within the first year had lower body mass index, milder obstructive sleep apnea, less sleepiness, and more often had symptoms of initial and late insomnia compared with long-term positive airway pressure users at baseline. Both initial and late insomnia were after adjustment still significantly associated with being an early quitter among subjects with body mass index insomnia are associated with early quitting on positive airway pressure among non-obese subjects. © 2016 European Sleep Research Society.

  1. Superconductivity at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, N B; Ginzburg, N I

    1969-07-01

    Work published during the last 3 or 4 yrs concerning the effect of pressure on superconductivity is reviewed. Superconducting modifications of Si, Ge, Sb, Te, Se, P and Ce. Change of Fermi surface under pressure for nontransition metals. First experiments on the influence of pressure on the tunneling effect in superconductors provide new information on the nature of the change in phonon and electron energy spectra of metals under hydrostatic compression. 78 references.

  2. Treatment of sleep-disordered breathing with positive airway pressure devices: technology update.

    Science.gov (United States)

    Johnson, Karin Gardner; Johnson, Douglas Clark

    2015-01-01

    Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features.

  3. High Blood Pressure in Pregnancy

    Science.gov (United States)

    ... of the baby. Controlling your blood pressure during pregnancy and getting regular prenatal care are important for ... your baby. Treatments for high blood pressure in pregnancy may include close monitoring of the baby, lifestyle ...

  4. Sleep disorders among high school students in New Zealand

    Directory of Open Access Journals (Sweden)

    Fernando AT

    2013-12-01

    Full Text Available INTRODUCTION: Adolescents are known to have high risk factors for sleep disorders, yet the youth rates of sleep disturbances are unknown. AIM: This study aimed to determine the prevalence of sleep disorders among New Zealand high school students. METHODS: The Auckland Sleep Questionnaire (ASQ was administered to high school students at six schools in the North Island. Schools were chosen to reflect a range of ethnicities and school deciles, which identify the socioeconomic status of households in the school catchment area. RESULTS: A total of 1388 students completed the ASQ. The median age was 17 years (range 14-23 and females represented 43.5% (n=604 of the total group. A total of 37.2% of the students surveyed reported having significant sleep symptoms lasting longer than one month. Depression and anxiety were present in 51.7% and 44.8% of students reporting a sleep problem, respectively. A moderate correlation was observed between sleep problems and depression (r=0.34, p<0.01, and sleep problems and anxiety (r=0.31, p<0.01. Problem alcohol use and other substance use were more common in students with sleep symptoms (12.2% and 5.5% respectively. No difference was found in the rate of sleep problems reported by different ethnic groups. DISCUSSION: A considerable proportion of students surveyed reported significant sleep symptoms. This study has the potential to aid physicians within New Zealand in better appreciating the burden of sleep disorders faced by young people and in effectively assessing and managing different causes of sleep symptoms in this demographic.

  5. AASM standards of practice compliant validation of actigraphic sleep analysis from SOMNOwatch(TM) versus polysomnographic sleep diagnostics shows high conformity also among subjects with sleep disordered breathing

    International Nuclear Information System (INIS)

    Dick, R; Schulz, J; Penzel, T; Fietze, I; Partinen, M; Hein, H

    2010-01-01

    In recent AASM practice, parameter actimetry is cited to measure total sleep time in obstructive sleep apnoea patients, when polysomnography is not available. An actigraph was therefore compared to polysomnographic data in 28 subjects with known sleep disordered breathing. Total sleep time (TST), sleep period time (SPT), sleep efficiency (SE), sustained sleep efficiency (SSE), sleep onset latency (SL) and sleep/wake pattern were compared to gold standard polysomnography. The results of an epoch-by-epoch comparison of sleep/wake from actigraphy to sleep stages from polysomnography gave a sensitivity of 90.2%, a specificity of 95.2% and an overall accuracy of 85.9%. Correlations were moderately strong for SE (0.71, p < 0.001) and SSE (0.65, p < 0.001) and high for TST (0.89, p < 0.001), SPT (0.91, p < 0.001) and SL (0.89, p < 0.001). It was concluded that actigraphy is not identical with PSG recording but gives good results in sleep/wake patterns and predicting TST, SPT, SSE, SE and SL also in sleep apnoea patients not suffering from other sleep disorders. The difficult detection of correct sleep onset causes SSE and SL to be less predictable. Therefore a 15-epoch criterion was introduced and resulted in high correlation of 0.89 for sleep latency, but has to be tested on a bigger population

  6. [Quality of sleep and academic performance in high school students].

    Science.gov (United States)

    Bugueño, Maithe; Curihual, Carolina; Olivares, Paulina; Wallace, Josefa; López-AlegrÍa, Fanny; Rivera-López, Gonzalo; Oyanedel, Juan Carlos

    2017-09-01

    Sleeping and studying are the day-to-day activities of a teenager attending school. To determine the quality of sleep and its relationship to the academic performance among students attending morning and afternoon shifts in a public high school. Students of the first and second year of high school answered an interview about socio-demographic background, academic performance, student activities and subjective sleep quality; they were evaluated using the Pittsburgh Sleep Quality Index (PSQI). The interview was answered by 322 first year students aged 15 ± 5 years attending the morning shift and 364 second year students, aged 16 ± 0.5 years, attending the afternoon shift. The components: sleep latency, habitual sleep efficiency, sleep disturbance, drug use and daytime dysfunction were similar and classified as good in both school shifts. The components subjective sleep quality and duration of sleep had higher scores among students of the morning shift. The mean grades during the first semester of the students attending morning and afternoon shifts were 5.9 and 5.8, respectively (of a scale from 1 to 7). Among students of both shifts, the PSQI scale was associated inversely and significantly with academic performance. A bad sleep quality influences academic performance in these students.

  7. Changes in blood pressure and sleep duration in patients with blue light-blocking/yellow-tinted intraocular lens (CHUKYO study).

    Science.gov (United States)

    Ichikawa, Kazuo

    2014-07-01

    Blood pressure and sleep duration may be influenced by retinal light exposure. Cataracts may exert such an influence by decreasing the transparency of the crystalline lens. A large-scale clinical study was conducted to examine changes in blood pressure and sleep duration after intraocular lens (IOL) implantation during cataract surgery and to investigate how different types of IOL influence the degree of these effects. Using a questionnaire, we collected information, including blood pressure measurement and sleep duration, from 1367 patients (1367 eyes) before IOL implantation, 1 week after IOL implantation and 1 month after IOL implantation. Systolic and diastolic blood pressures were significantly decreased in the total patient group after implantation. The decrease in systolic blood pressure 1 month after implantation was significantly more in patients who received a yellow-tinted IOL than it was in those who received an ultraviolet (UV) light-filtering IOL. The post-implantation sleep duration, including naps, became shorter in patients who had slept too much and became longer in those who had slept too little before IOL implantation. Our observations suggest that a yellow-tinted IOL is better for patients with high blood pressure than a UV light-filtering IOL. Furthermore, the yellow-tinted IOL is as good as the UV light-filtering IOL for improving sleep duration. A pale yellow-tinted IOL is likely to be superior to a moderate yellow-tinted IOL in terms of allowing patients to discriminate different colors. Thus, the pale yellow-tinted IOL appears to be better for patients than the UV light-filtering IOL and the moderate yellow-tinted IOL.

  8. Validation of a novel automatic sleep spindle detector with high performance during sleep in middle aged subjects

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Christensen, Julie A. E.; Kempfner, Jacob

    2012-01-01

    Many of the automatic sleep spindle detectors currently used to analyze sleep EEG are either validated on young subjects or not validated thoroughly. The purpose of this study is to develop and validate a fast and reliable sleep spindle detector with high performance in middle aged subjects....... An automatic sleep spindle detector using a bandpass filtering approach and a time varying threshold was developed. The validation was done on sleep epochs from EEG recordings with manually scored sleep spindles from 13 healthy subjects with a mean age of 57.9 ± 9.7 years. The sleep spindle detector reached...

  9. High Flow Nasal Cannula Therapy for Improving Obstructive Sleep Apnea: A Case Report

    Directory of Open Access Journals (Sweden)

    Se Joong Kim

    2015-06-01

    Full Text Available Although continuous positive airway pressure is the treatment of choice for obstructive sleep apnea, its compliance is low. Therefore, alternative therapeutic strategies are often required. High flow nasal cannula therapy uses an air compressor to deliver a constant flow of oxygen via the nasal cannula at a maximum of 60 L/m. It can produce positive end expiratory pressure and increase end expiratory pharyngeal pressure, which can help to alleviate upper airway obstruction. This is a case report of high flow nasal cannula therapy for a 71 year-old man. He had an obstructive sleep apnea and severe desaturation but failed to use continuous positive airway pressure. He underwent titration with high flow nasal cannula under polysomnography. Using high flow nasal cannula at an airflow of 45 L/m, his apnea-hypopnea, respiratory arousal and oxygen desaturation were improved. Importantly, he is very compliant with high flow nasal cannula therapy.

  10. What Is High Blood Pressure?

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More What is High Blood Pressure? Updated:Feb 27,2018 First, let’s define high ... resources . This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  11. Sleep patterns and habits in high school students in Iran

    Directory of Open Access Journals (Sweden)

    Moini Rozita

    2008-03-01

    Full Text Available Abstract Background Sleep patterns and habits in high school students in Iran have not been well studied to date. This paper aims to re-address this balance and analyse sleep patterns and habits in Iranian children of high school age. Methods The subjects were 1,420 high school students randomly selected by stratified cluster sampling. This was a self-report study using a questionnaire which included items about usual sleep/wake behaviours over the previous month, such as sleep schedule, falling asleep in class, difficulty falling asleep, tiredness or sleepiness during the day, difficulty getting up in the morning, nightmares, and taking sleeping pills. Results The mean duration of night sleep was 7.7 h, with no difference between girls, boys, and school year (grade. The mean time of waking in the morning was not different between genders. About 9.9% of the girls and 4.6% of the boys perceived their quality of sleep as being bad, and 58% of them reported sleepiness during the day. About 4.2% of the subjects had used medication to enhance sleep. The time of going to bed was associated with grade level and gender. Sleep latency was not associated with gender and grade leve, l and 1.4% experienced bruxism more than four times a week. Conclusion Our results are in contrast with that of previous studies that concluded sleep duration is shorter in Asia than in Europe, that boys woke-up significantly later than girls, and that the frequency of sleep latency category was associated with gender and grade level. The magnitude of the daytime sleepiness, daytime sleepiness during classes, sleep latency, and incidences of waking up at night represent major public health concerns for Iran.

  12. Sibutramine versus continuous positive airway pressure in obese obstructive sleep apnoea patients.

    Science.gov (United States)

    Ferland, A; Poirier, P; Sériès, F

    2009-09-01

    The aim of the present study was to compare the efficacy of 1 yr of sibutramine-induced weight loss versus continuous positive airway pressure (CPAP) treatment on sleep-disordered breathing, cardiac autonomic function and systemic blood pressure in obese patients with obstructive sleep apnoea. Subjects with a body mass index of > or =30 kg.m(-2) without previous treatment for obstructive sleep apnoea underwent either sibutramine (n = 22) or CPAP (n = 18) treatment for 1 yr. Sibutramine induced a 5.4+/-1.4 kg decrease in body weight compared to the CPAP group, in which no changes in anthropometric variables were observed. The CPAP treatment improved all sleep and respiratory variables, whereas sibutramine-induced weight loss improved only nocturnal arterial oxygen saturation profile. Only CPAP treatment improved night-time systolic and diastolic blood pressure and 24-h and daytime ambulatory diastolic blood pressure. Sibutramine-induced weight loss had no impact on indices of heart rate variability, whereas CPAP treatment increased daytime time domain indices. CPAP treatment for 1 yr had beneficial impacts on nocturnal breathing disturbances, and improved nocturnal oxygenation, night-time systolic and diastolic blood pressure, and daytime cardiac parasympathetic modulation. Sibutramine did not improve sleep-disordered breathing, systemic blood pressure or heart rate variability. There were no adverse effects, such as increment in blood pressure or arrhythmias, associated with this treatment regimen.

  13. Improvement in Physical Activity in Persons With Obstructive Sleep Apnea Treated With Continuous Positive Airway Pressure.

    Science.gov (United States)

    Jean, Raymonde E; Duttuluri, Manideep; Gibson, Charlisa D; Mir, Sadaf; Fuhrmann, Katherine; Eden, Edward; Supariwala, Azhar

    2017-03-01

    Exercise improves sleep quality, yet people with untreated obstructive sleep apnea (OSA) may engage in less physical activity (PA) due to fatigue and daytime sleepiness. We examined changes in PA and sleep quality before and after treatment with continuous positive airway pressure (CPAP) in OSA patients. In this prospective longitudinal study, persons with a primary diagnosis of OSA were enrolled at a community-based hospital in New York City. At 3 time intervals pre- and post-CPAP (3-8 months), we measured sleep quality using validated questionnaires, perceived PA using the International Physical Activity Questionnaire (IPAQ), and actual PA using pedometer steps per day. We sought to investigate how CPAP use and changes in sleep quality impacted the number of steps taken, as recorded in pedometer steps. In total, 62 patients were enrolled in the study from March 2012 to July 2014. In all, patients averaged 53 years of age, and 26 patients (42%) were female. Among all participants, 86% of persons had moderate to severe sleep apnea (AHI ≥15). Approximately 73% of participants were compliant with CPAP use. Poor sleep quality correlated with lower actual PA (P = .004) at baseline. At 3 and 7 months, there was significant improvement in sleep quality (Δ -2.63 ± 3.4 and Δ -3.5 ± 3.8; P improvement in sleep quality and actual PA.

  14. High pressure shaft seal

    International Nuclear Information System (INIS)

    Martinson, A.R.; Rogers, V.D.

    1980-01-01

    In relation to reactor primary coolant pumps, mechanical seal assembly for a pump shaft is disclosed which features a rotating seal ring mounting system which utilizes a rigid support ring loaded through narrow annular projections in combination with centering non-sealing O-rings which effectively isolate the rotating seal ring from temperature and pressure transients while securely positioning the ring to adjacent parts. A stationary seal ring mounting configuration allows the stationary seal ring freedom of motion to follow shaft axial movement up to 3/4 of an inch and shaft tilt about the pump axis without any change in the hydraulic or pressure loading on the stationary seal ring or its carrier. (author)

  15. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: A high density EEG investigation.

    Science.gov (United States)

    Plante, David T; Goldstein, Michael R; Cook, Jesse D; Smith, Richard; Riedner, Brady A; Rumble, Meredith E; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M; Peterson, Michael J

    2016-02-01

    Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. These results demonstrate a homeostatic response to partial sleep loss in humans. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  16. Oral appliance therapy versus nasal continuous positive airway pressure in obstructive sleep apnoea syndrome: a randomised, placebo-controlled trial on self-reported symptoms of common sleep disorders and sleep-related problems

    NARCIS (Netherlands)

    Nikolopoulou, M.; Byraki, A.; Ahlberg, J.; Heymans, M. W.; Hamburger, H. L.; de Lange, J.; Lobbezoo, F.; Aarab, G.

    2017-01-01

    Obstructive sleep apnoea syndrome (OSAS) is associated with several sleep disorders and sleep-related problems. Therefore, the aim of this study was to compare the effects of a mandibular advancement device (MAD) with those of nasal continuous positive airway pressure (nCPAP) on self-reported

  17. Association of sleep duration with arterial blood pressure profile of Gujarati Indian adolescents

    Directory of Open Access Journals (Sweden)

    Shaikh Wasim

    2010-01-01

    Full Text Available Background and Aim: Recently, National Health and Nutritional Examination Survey-1 data analysis found short sleep duration as a risk factor for hypertension in the U.S. population. However, since ethnic differences exist in the aetiopathogenesis of diseases, the current study was undertaken to study the effect of sleep duration on the blood pressure profile of Gujarati Indian adolescents. Materials and Methods: A cross-sectional study was conducted on 489 Gujarati Indian adolescents of age group 16-19 years studying in school and colleges in the local population. The participants were assessed for their sleep duration, physical activity status, body composition, blood pressure profile and cardiovascular reactivity. The sleep duration was reported by the subjects as the number of hours they slept on most of the nights in a week over the last one year. The observations of the study were then analyzed after grouping them into: 1 Adequate Sleep Duration at Night, ASDN (≥ 7 hrs and 2 Inadequate Sleep Duration at Night, ISDN (< 7 hrs groups. Student′s unpaired t-test was used to study if any significant difference (P< 0.05 existed between the groups. Results: No significant difference was found in Systolic blood pressure, Diastolic blood pressure, Pulse pressure and Mean arterial pressure between the ASDN group and the ISDN group. Physical activity status also did not differ between the two groups. However, adolescents of ISDN group showed a significantly higher level of adiposity and cardiovascular reactivity as compared to adolescents of ASDN group. Conclusion: Although short sleep duration is associated with a higher level of adiposity and cardiovascular reactivity in Gujarati Indian adolescents, it does not affect the resting blood pressure profile of these adolescents. However, longitudinal studies would be required to observe if the changes in adiposity and cardiovascular reactivity affect these adolescents in later life.

  18. High Blood Pressure - Multiple Languages

    Science.gov (United States)

    ... Being 8 - High Blood Pressure - Amarɨñña / አማርኛ (Amharic) MP3 Siloam Family Health Center Arabic (العربية) Expand Section ... Being 8 - High Blood Pressure - myanma bhasa (Burmese) MP3 Siloam Family Health Center Chinese, Simplified (Mandarin dialect) ( ...

  19. Cardiovascular risk in patients with sleep apnoea with or without continuous positive airway pressure therapy

    DEFF Research Database (Denmark)

    Lamberts, Morten; Nielsen, O W; Lip, G Y H

    2014-01-01

    BACKGROUND: The prognostic significance of age and continuous positive airway pressure (CPAP) therapy on cardiovascular disease in patients with sleep apnoea has not been assessed previously. METHODS: Using nationwide databases, the entire Danish population was followed from 2000 until 2011. First......-time sleep apnoea diagnoses and use of CPAP therapy were determined. Incidence rate ratios (IRRs) of ischaemic stroke and myocardial infarction (MI) were analysed using Poisson regression models. RESULTS: Amongst 4.5 million individuals included in the study, 33 274 developed sleep apnoea (mean age 53, 79......% men) of whom 44% received persistent CPAP therapy. Median time to initiation of CPAP therapy was 88 days (interquartile range 34-346). Patients with sleep apnoea had more comorbidities compared to the general population. Crude rates of MI and ischaemic stroke were increased for sleep apnoea patients...

  20. Identifying patients at high risk for obstructive sleep apnoea ...

    African Journals Online (AJOL)

    Background: Obstructive sleep apnoea is associated with significant health consequences. A significant proportion of hospitalized patients at risk for obstructive sleep apnoea were never identified and referred for polysomnography for diagnosis. The objective of this study was to determine the factors associated with high ...

  1. Fundamentals of high pressure adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

    2009-12-15

    High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

  2. Can Pillow Height Effect the Body Pressure Distribution and Sleep Comfort: a Study of Quinquagenarian Women

    Science.gov (United States)

    Li, Xinzhu; Hu, Huimin; Liao, Su

    2018-03-01

    A proper sleeping pillow can relax the neck muscles during sleep, yet does not impose stress on the spine or other tissues. By analyzing the different body pressure and subjective comfort evaluation of quinquagenarian women with different pillow heights (3cm, 7cm, 11cm and 15cm), this paper found that as the pillow height increased, the neck contact pressure, contact area and force increased at the same time, as well as the peak force and peak contact pressure gradually shifted from the head to the hip area. It was shown that the pillow with a height of 7cm was the most comfortable for supine positions.

  3. Predicting uptake of continuous positive airway pressure (CPAP) therapy in obstructive sleep apnoea (OSA)

    DEFF Research Database (Denmark)

    Skinner, Timothy; McNeil, Lindsay; Olaithe, Michelle

    2013-01-01

    diagnosed with OSA. Epworth sleepiness scale (ESS), Fatigue Severity Scale, Depression Anxiety Stress Scale and Illness Perception Questionnaire-Revised (IPQ-R) were administered at time of sleep study. These, patient demographics and sleep study variables were used to determine factors predicting patient......Purpose: Obstructive sleep apnoea (OSA) is a common disorder, for which continuous positive airway pressure (CPAP) therapy is a standard treatment. Despite its well-established efficacy, many patients choose not to initiate CPAP treatment. The present study investigated the degree to which...

  4. Sleep Monitoring Based on a Tri-Axial Accelerometer and a Pressure Sensor

    Directory of Open Access Journals (Sweden)

    Yunyoung Nam

    2016-05-01

    Full Text Available Sleep disorders are a common affliction for many people even though sleep is one of the most important factors in maintaining good physiological and emotional health. Numerous researchers have proposed various approaches to monitor sleep, such as polysomnography and actigraphy. However, such approaches are costly and often require overnight treatment in clinics. With this in mind, the research presented here has emerged from the question: “Can data be easily collected and analyzed without causing discomfort to patients?” Therefore, the aim of this study is to provide a novel monitoring system for quantifying sleep quality. The data acquisition system is equipped with multimodal sensors, including a three-axis accelerometer and a pressure sensor. To identify sleep quality based on measured data, a novel algorithm, which uses numerous physiological parameters, was proposed. Such parameters include non-REM sleep time, the number of apneic episodes, and sleep durations for dominant poses. To assess the effectiveness of the proposed system, three participants were enrolled in this experimental study for a duration of 20 days. From the experimental results, it can be seen that the proposed monitoring system is effective for quantifying sleep quality.

  5. Sleep

    Science.gov (United States)

    ... Institute (NHLBI). 1 Mood. Sleep affects your mood. Insufficient sleep can cause irritability that can lead to trouble with relationships, ... basics/understanding_sleep.htm#dynamic_activity Centers for Disease ... insufficient rest or sleep among adults—United States, 2008. MMWR, 58 (42), ...

  6. High pressure phase transformations revisited.

    Science.gov (United States)

    Levitas, Valery I

    2018-04-25

    High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

  7. High pressure phase transformations revisited

    Science.gov (United States)

    Levitas, Valery I.

    2018-04-01

    High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

  8. Blood Pressure, Sleep Quality and Fatigue in Shift Working Police Officers: Effects of a Twelve Hour Roster System on Cardiovascular and Sleep Health

    Directory of Open Access Journals (Sweden)

    Jaymen L. Elliott

    2016-01-01

    Full Text Available Background: Police officers have been reported to exhibit a high incidence of pathologies, which present prematurely in an otherwise healthy population. Shift work has also been associated with an increased risk of cardiovascular and sleep disorders, attributable to its propensity for circadian rhythm dysfunction. However, contention exists as to whether shift work has a direct effect upon blood pressure (BP regulation. Methods: This cross-sectional study sought to determine changes in BP and associations with the overall sleep quality and fatigue in 206 general duties police officers (n = 140 males of the New South Wales Police Force in Australia. The subjects’ BP was assessed before and after their twelve hour shift, during which time they also completed the Lifestyle Appraisal Questionnaire, Pittsburgh Sleep Quality Index (PSQI, Epworth Sleepiness Scale and Fatigue Severity Scale (FSS. Results: Poor sleep quality (PSQI and fatigue severity (FSS were found to predominate in the sample (69% and 51% respectively. Although there was no change in BP for male participants, female officers’ systolic blood pressure (SBP was found to increase significantly across the shift (p < 0.001, but with no change found in females’ diastolic blood pressure (DBP. Finally, higher pre and post-shift SBP (r = −0.26, p = 0.001; r = −0.25, p = 0.001, respectively and DBP (r = −0.26, p = 0.001; r = −0.26, p = 0.001, respectively were significantly correlated with lower FSS scores after accounting for age, waist-hip ratio and lifestyle risk factors. Conclusions: Based on these preliminary findings, there was a significant increase in SBP of female police officers after shift work, while BP and fatigue levels in all police officers were strongly related. Moreover, the predominating poor sleep quality and impact of fatigue in this sample remain a concern. Further research is required to ensure the physiological welfare of police officers, while strategies

  9. High pressure experimental water loop

    International Nuclear Information System (INIS)

    Grenon, M.

    1958-01-01

    A high pressure experimental water loop has been made for studying the detection and evolution of cladding failure in a pressurized reactor. The loop has been designed for a maximum temperature of 360 deg. C, a maximum of 160 kg/cm 2 and flow rates up to 5 m 3 /h. The entire loop consists of several parts: a main circuit with a canned rotor circulation pump, steam pressurizer, heating tubes, two hydro-cyclones (one de-gasser and one decanter) and one tubular heat exchanger; a continuous purification loop, connected in parallel, comprising pressure reducing valves and resin pots which also allow studies of the stability of resins under pressure, temperature and radiation; following the gas separator is a gas loop for studying the recombination of the radiolytic gases in the steam phase. The preceding circuits, as well as others, return to a low pressure storage circuit. The cold water of the low pressure storage flask is continuously reintroduced into the high pressure main circuit by means of a return pump at a maximum head of 160 kg /cm 2 , and adjusted to the pressurizer level. This loop is also a testing bench for the tight high pressure apparatus. The circulating pump and the connecting flanges (Oak Ridge type) are water-tight. The feed pump and the pressure reducing valves are not; the un-tight ones have a system of leak recovery. To permanently check the tightness the circuit has been fitted with a leak detection system (similar to the HRT one). (author) [fr

  10. Psoriasis and high blood pressure.

    Science.gov (United States)

    Salihbegovic, Eldina Malkic; Hadzigrahic, Nermina; Suljagic, Edin; Kurtalic, Nermina; Sadic, Sena; Zejcirovic, Alema; Mujacic, Almina

    2015-02-01

    Psoriasis is a chronic skin ailment which can be connected with an increased occurrence of other illnesses, including high blood pressure. A prospective study has been conducted which included 70 patients affected by psoriasis, both genders, older than 18 years. Average age being 47,14 (SD= ±15,41) years, from that there were 36 men or 51,43 and 34 women or 48,57%. Average duration of psoriasis was 15,52 (SD=±12,54) years. Frequency of high blood pressure in those affected by psoriasis was 54,28%. Average age of the patients with psoriasis and high blood pressure was 53,79 year (SD=±14,15) and average duration of psoriasis was 17,19 years (SD=±13,51). Average values of PASI score were 16,65. Increase in values of PASI score and high blood pressure were statistically highly related (r=0,36, p=0,0001). Psoriasis was related to high blood pressure and there was a correlation between the severity of psoriasis and high blood pressure.

  11. High Blood Pressure and Women

    Science.gov (United States)

    ... is known as gestational hypertension, a form of secondary hypertension caused by the pregnancy that usually disappears after delivery. If the mother is not treated, high blood pressure can be dangerous to both the mother ...

  12. High Pressure Industrial Water Facility

    Science.gov (United States)

    1992-01-01

    In conjunction with Space Shuttle Main Engine testing at Stennis, the Nordberg Water Pumps at the High Pressure Industrial Water Facility provide water for cooling the flame deflectors at the test stands during test firings.

  13. High Pressure Research on Materials

    Indian Academy of Sciences (India)

    example, represents the stress on the x plane in the y direction. There are three .... optical studies and studying compressibility of fluids. 3.2 Opposed ..... [4] G N Peggs, High Pressure Measurement Techniques, Applied Science. Publishers ...

  14. Preschool Children with Obstructive Sleep Apnea: The Beginnings of Elevated Blood Pressure?

    Science.gov (United States)

    Nisbet, Lauren C.; Yiallourou, Stephanie R.; Biggs, Sarah N.; Nixon, Gillian M.; Davey, Margot J.; Trinder, John A.; Walter, Lisa M.; Horne, Rosemary S. C.

    2013-01-01

    Study Objectives: In adults and older children, snoring and obstructive sleep apnea (OSA) are associated with elevated blood pressure (BP). However, BP has not been assessed in preschool children, the age of highest OSA prevalence. We aimed to assess overnight BP in preschool children with snoring and OSA using pulse transit time (PTT), an inverse continuous indicator of BP changes. Design: Overnight polysomnography including PTT. Children were grouped according to their obstructive apnea-hypopnea index (OAHI); control (no snoring, with OAHI of one event or less per hour), primary snoring (OAHI one event or less per hour), mild OSA (OAHI greater than one event to five events per hour) and moderate-severe OSA (OAHI more than five events per hour). Setting: Pediatric sleep laboratory. Patients: There were 128 clinically referred children (aged 3-5 years) and 35 nonsnoring community control children. Measurement and Results: PTT was averaged for each 30-sec epoch of rapid eye movement (REM) or nonrapid eye movement (NREM) sleep and normalized to each child's mean wake PTT. PTT during NREM was significantly higher than during REM sleep in all groups (P Biggs SN; Nixon GM; Davey MJ; Trinder JA; Walter LM; Horne RSC. Preschool children with obstructive sleep apnea: the beginnings of elevated blood pressure? SLEEP 2013;36(8):1219-1226. PMID:23904682

  15. High Blood Pressure (Hypertension) (For Parents)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Parents / Hypertension (High Blood Pressure) What's ... High Blood Pressure) Treated? Print What Is Hypertension (High Blood Pressure)? Blood pressure is the pressure of blood against ...

  16. Sleep apnea is associated with bronchial inflammation and continuous positive airway pressure-induced airway hyperresponsiveness.

    Science.gov (United States)

    Devouassoux, Gilles; Lévy, Patrick; Rossini, Eliane; Pin, Isabelle; Fior-Gozlan, Michèle; Henry, Mireille; Seigneurin, Daniel; Pépin, Jean-Louis

    2007-03-01

    Obstructive sleep apnea syndrome (OSA) is associated with systemic and upper airway inflammation. Pharyngeal inflammation has a potential role in upper airway collapse, whereas systemic inflammation relates to cardiovascular morbidity. However, the presence of an inflammatory involvement of lower airway has been poorly investigated. The aim of the study was to demonstrate an inflammatory process at the bronchial level in patients with OSA and to analyze effects of continuous positive airway pressure (CPAP) application and humidification on bronchial mucosa. The study was conducted by using sequential induced sputum for cell analysis and IL-8 production, nitric oxide exhalation measurement, and methacholine challenge before and after CPAP. Bronchial neutrophilia and a high IL-8 concentration were observed in untreated OSA compared with controls (75% +/- 20% vs 43% +/- 12%, P Obstructive sleep apnea syndrome is associated with bronchial inflammation. Our data demonstrate CPAP effect on the development of AHR, possibly facilitated by the pre-existing inflammation. Both issues should be evaluated during long-term CPAP use. Results showing a spontaneous bronchial inflammation in OSA and the development of a CPAP-related AHR require a long-term follow-up to evaluate consequences on chronic bronchial obstruction.

  17. Academic achievement of junior high school students with sleep disorders

    Directory of Open Access Journals (Sweden)

    Fijri Auliyanti

    2015-03-01

    Full Text Available Background Sleep disorders are prevalent in adolescents and may influence their academic achievement. To date, no study has been done in Indonesia on academic achievement in students with sleep disorders and its related factors. Objective To assess for relationships between academic achievement and related factors, including gender, motivation and learning strategies, IQ level, maternal educational level, socioeconomic status, family structure, after-hours education program, presence of TV/computer in the bedroom, sleep duration during school days, as well as bedtime and wakeup time difference in junior high school students with sleep disorders. Methods This cross-sectional study was performed from January to March 2013. Subjects were students from five junior high schools in Jakarta who fulfilled the criteria for sleep disorders based on the Sleep Disturbance Scale for Children questionnaire. Results There were 111 study subjects. The prevalence of sleep disorders was 39.7%, mostly in difficulties initiating and maintaining sleep (70.2%. Below-average academic achievement was seen in 47.6% of subjects. Factors significantly related to below-average academic achievement were after-hours education program (prevalence ratio 5.6; 95%CI 1.36 to 23.18; P = 0.017, average IQ level (prevalence ratio 3.26; 95%CI 1.38 to 7.71; P = 0.007, and male gender (prevalence ratio 2.68; 95%CI 1.06 to 6.78; P = 0.037. Conclusion Among junior high school students with sleep disorders, factors related to below-average academic achievement are afterhours education program (more than 2 types, the average IQ level, and male gender.

  18. Factors associated with sleep duration in Brazilian high school students.

    Science.gov (United States)

    Gomes Felden, Érico Pereira; Barbosa, Diego Grasel; Junior, Geraldo Jose Ferrari; Santos, Manoella De Oliveira; Pelegrini, Andreia; Silva, Diego Augusto Santos

    2017-01-01

    The aim of this study was to investigate the factors associated with short sleep duration on southern Brazilian high school students. Our study was comprised of 1,132 adolescents aged 14 to 19 years, enrolled in public high schools in São José, Brazil. The students answered a questionnaire about working (work and workload), health perception, smoking, school schedule, sleep (duration and daytime sleepiness), and socio-demographics data. The results showed that more than two thirds of adolescent workers had short sleep duration (76.7%), and those with a higher workload (more than 20 hours) had a shorter sleep duration (7.07 hours) compared to non-workers (7.83 hours). In the analysis of factors associated with short sleep duration, adolescents who worked (OR = 2.12, 95% CI 1.53 to 2.95) were more likely to have short sleep duration compared to those who did not work. In addition, older adolescents (17-19 years) and students with poor sleep quality were 40% and 55% more likely to have short sleep duration compared to younger adolescents (14-16 years) and students with good sleep quality, respectively. Adolescents with daytime sleepiness were more likely to have short sleep duration (OR = 1.49, 95% CI 1.06 to 2.07) compared to those without excessive daytime sleepiness. In addition students of the morning shift (OR = 6.02, 95% CI 4.23 to 8.57) and evening shift (OR = 2.16, 95% CI 1.45 to 3.22) were more likely to have short sleep duration compared to adolescents of the afternoon shift. Thereby adolescents who are workers, older, attended morning and evening classes and have excessive daytime sleepiness showed risk factors for short sleep duration. In this sense, it is pointed out the importance of raising awareness of these risk factors for short sleep duration of students from public schools from São José, located in southern Brazil.

  19. Unfinished tasks foster rumination and impair sleeping - particularly if leaders have high performance expectations.

    Science.gov (United States)

    Syrek, Christine J; Antoni, Conny H

    2014-10-01

    This study examines the relationship between time pressure and unfinished tasks as work stressors on employee well-being. Relatively little is known about the effect of unfinished tasks on well-being. Specifically, excluding the impact of time pressure, we examined whether the feeling of not having finished the week's tasks fosters perseverative cognitions and impairs sleep. Additionally, we proposed that leader performance expectations moderate these relationships. In more detail, we expected the detrimental effect of unfinished tasks on both rumination and sleep would be enhanced if leader expectations were perceived to be high. In total, 89 employees filled out online diary surveys both before and after the weekend over a 5-week period. Multilevel growth modeling revealed that time pressure and unfinished tasks impacted rumination and sleep on the weekend. Further, our results supported our hypothesis that unfinished tasks explain unique variance in the dependent variables above and beyond the influence of time pressure. Moreover, we found the relationship between unfinished tasks and both rumination and sleep was moderated by leader performance expectations. Our results emphasize the importance of unfinished tasks as a stressor and highlight that leadership, specifically in the form of performance expectations, contributes significantly to the strength of this relationship.

  20. High risk for obstructive sleep apnea and other sleep disorders among overweight and obese pregnant women.

    Science.gov (United States)

    Rice, Jayne R; Larrabure-Torrealva, Gloria T; Luque Fernandez, Miguel Angel; Grande, Mirtha; Motta, Vicky; Barrios, Yasmin V; Sanchez, Sixto; Gelaye, Bizu; Williams, Michelle A

    2015-09-02

    Obstructive sleep apnea (OSA), a common and serious disorder in which breathing repeatedly stops during sleep, is associated with excess weight and obesity. Little is known about the co-occurrence of OSA among pregnant women from low and middle-income countries. We examined the extent to which maternal pre-pregnancy overweight or obesity status are associated with high risk for OSA, poor sleep quality, and excessive daytime sleepiness in 1032 pregnant women in Lima, Peru. The Berlin questionnaire was used to identify women at high risk for OSA. The Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) were used to examine sleep quality and excessive daytime sleepiness, respectively. Multinomial logistic regression procedures were employed to estimate odds ratios (aOR) and 95% confidence intervals (CI) adjusted for putative confounding factors. Compared with lean women (overweight women (25-29.9 kg/m(2)) had 3.69-fold higher odds of high risk for OSA (95% CI 1.82-7.50). The corresponding aOR for obese women (≥30 kg/m(2)) was 13.23 (95% CI: 6.25-28.01). Obese women, as compared with their lean counterparts had a 1.61-fold higher odds of poor sleep quality (95% CI: 1.00-2.63). Overweight or obese pregnant women have increased odds of sleep disorders, particularly OSA. OSA screening and risk management may be indicated among pregnant women in low and middle income countries, particularly those undergoing rapid epidemiologic transitions characterized by increased prevalence of excessive adult weight gain.

  1. Treatment of sleep-disordered breathing with positive airway pressure devices: technology update

    Directory of Open Access Journals (Sweden)

    Johnson KG

    2015-10-01

    Full Text Available Karin Gardner Johnson, Douglas Clark Johnson Department of Medicine, Baystate Medical Center, Springfield, MA, USA Abstract: Many types of positive airway pressure (PAP devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features. Keywords: BiPAP, CPAP, iVAPS, AVAPS, ASV, positive pressure respiration, instrumentation, treatment algorithm

  2. Terbium oxide at high pressures

    International Nuclear Information System (INIS)

    Dogra, Sugandha; Sharma, Nita Dilawar; Singh, Jasveer; Bandhyopadhyay, A.K.

    2011-01-01

    In this work we report the behaviour of terbium oxide at high pressures. The as received sample was characterized at ambient by X-ray diffraction and Raman spectroscopy. The X-ray diffraction showed the sample to be predominantly cubic Tb 4 O 7 , although a few peaks also match closely with Tb 2 O 3 . In fact in a recent study done on the same sample, the sample has been shown to be a mixture of Tb 4 O 7 and Tb 2 O 3 . The sample was subjected to high pressures using a Mao-Bell type diamond anvil cell upto a pressure of about 42 GPa with ruby as pressure monitor

  3. High Pressure Treatment in Foods

    OpenAIRE

    Edwin Fabian Torres Bello; Gerardo González Martínez; Bernadette F. Klotz Ceberio; Dolores Rodrigo; Antonio Martínez López

    2014-01-01

    Abstract: High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non...

  4. Regional reductions in sleep electroencephalography power in obstructive sleep apnea: a high-density EEG study.

    Science.gov (United States)

    Jones, Stephanie G; Riedner, Brady A; Smith, Richard F; Ferrarelli, Fabio; Tononi, Giulio; Davidson, Richard J; Benca, Ruth M

    2014-02-01

    Obstructive sleep apnea (OSA) is associated with significant alterations in neuronal integrity resulting from either hypoxemia and/or sleep loss. A large body of imaging research supports reductions in gray matter volume, alterations in white matter integrity and resting state activity, and functional abnormalities in response to cognitive challenge in various brain regions in patients with OSA. In this study, we used high-density electroencephalography (hdEEG), a functional imaging tool that could potentially be used during routine clinical care, to examine the regional distribution of neural activity in a non-clinical sample of untreated men and women with moderate/severe OSA. Sleep was recorded with 256-channel EEG in relatively healthy subjects with apnea-hypopnea index (AHI) > 10, as well as age-, sex-, and body mass index-matched controls selected from a research population initially recruited for a study on sleep and meditation. Sleep laboratory. Nine subjects with AHI > 10 and nine matched controls. N/A. Topographic analysis of hdEEG data revealed a broadband reduction in EEG power in a circumscribed region overlying the parietal cortex in OSA subjects. This parietal reduction in neural activity was present, to some extent, across all frequency bands in all stages and episodes of nonrapid eye movement sleep. This investigation suggests that regional deficits in electroencephalography (EEG) power generation may be a useful clinical marker for neural disruption in obstructive sleep apnea, and that high-density EEG may have the sensitivity to detect pathological cortical changes early in the disease process.

  5. The effect of continuous positive airway pressure on blood pressure in patients with obstructive sleep apnea syndrome

    Directory of Open Access Journals (Sweden)

    Giorgiana Dediu

    2017-12-01

    Full Text Available Introduction. Obstructive sleep apnea syndrome (OSAS is a disease with increasing prevalence nowadays, being associated with multiple cardiovascular diseases, such as arterial hypertension. The objective of the study was to evaluate the effect of continuous positive airway pressure (CPAP on blood pressure values. Materials and methods. We performed a prospective interventional study on 52 patients with obstructive sleep apnea syndrome. The patients were divided into 2 groups: Group A (who received both pharmacological and CPAP treatment and Group B (who received only pharmacological treatment, and were followed up at 3 and 6 months. The statistical analysis was made with SPSS and Microsoft Excel. At the same time, using the surrogate marker –RDW, we tried to evaluate the persistence of systemic inflammation, knowing that OSAS is associated with inflammation. Results. The systolic blood pressure values decreased at 6 months in all OSAS patients who have used CPAP, including patients with normal values of blood pressure. At the same time, the lack of OSAS treatment led to increased values of blood pressure by approximately 10 mmHg. We noticed a link between RDW, age and blood pressure values, respectively the increase of RDW and age may result in an increase in blood pressure. Conclusions. The OSAS treatment can decrease the blood pressure values. A higher RDW may be considered a negative prognostic factor for these patients, reflecting the role of systemic inflammation in the appearance of cardiovascular disorders.

  6. The effect of nocturnal CPAP therapy on the intraocular pressure of patients with sleep apnea syndrome.

    Science.gov (United States)

    Cohen, Yuval; Ben-Mair, Eyal; Rosenzweig, Eyal; Shechter-Amir, Dalia; Solomon, Arieh S

    2015-12-01

    Few studies have documented that nocturnal continuous positive airway pressure (CPAP) therapy is associated with an increase in intraocular pressure (IOP) in patients with severe obstructive sleep apnea syndrome (OSAS). We re-examined the effect of CPAP therapy on the IOP of OSAS patients. The IOP of two different groups of newly diagnosed OSAS patients was compared at their first sleep lab exam without CPAP treatment (non-CPAP treated group; n = 20) and at the second sleep lab exam with CPAP treatment (CPAP treated group; n = 31). The sleep lab exam (sleep period: from 11:00 p.m. until 6:00 a.m.) included IOP measurements, a complete ophthalmologic exam, and nocturnal hemodynamic recordings. The IOP was measured serially using rebound tonometer (IOP; ICARE® PRO) performed while in sitting and supine positions before, during, and after the sleep period. We compared the difference in IOP of CPAP and non-CPAP groups. The mean IOP of the CPAP and non-CPAP groups measured in sitting position before the sleep period was 13.33 ± 2.04 mmHg and 14.02 ± 2.44 mmHg, respectively (p = 0.9). Assuming a supine position for 1 minute significantly increased the IOP by 1.93 mmHg and 2.13 mmHg for both the non-CPAP and CPAP groups (paired t-test; p = 0.02, p = 0.001 respectively), but this IOP rise showed no difference between the two groups. The IOP increased significantly further after 7 hours of sleep in the supine position, and the mean IOP of the CPAP and non-CPAP groups was 19.2 ± 5.68 mmHg and 19.69 ± 5.61 mmHg respectively (independent t-test; p = 0.74). The rise in IOP for both groups was not correlated with any hemodynamic parameters. Three OSAS patients with glaucoma treated with CPAP had mean IOP of 23.75 mmHg after 7 hours of sleep. OSAS patients have a significant rise in IOP during the sleep period when comparing measurements before and after the sleep period; however, CPAP therapy did not affect the measured

  7. Sleep disorders in high school and pre-university students

    OpenAIRE

    Célia R.S. Rocha; Sueli Rossini; Rubens Reimão

    2010-01-01

    Adolescence is a period in which youngsters have to make choices such as applying for university. The selection process is competitive, and it brings distress and anxiety, risk factors for the appearance of sleep disorders. Objective: To verify the occurrence of sleep disorders in third-year high school and pre-university students. Method: This cross-sectional descriptive study comprised a sample of 529 students (M=241, F=288) from three public schools, four private schools and two pre-univer...

  8. Impact of obstructive sleep apnea on blood pressure in patients with hypertension

    Directory of Open Access Journals (Sweden)

    Gurubhagavatula I

    2011-12-01

    Full Text Available Barry Fields1, Indira Gurubhagavatula1–31Division of Sleep Medicine, Perelman School of Medicine, University of Pennsylvania, 2Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, 3Philadelphia VA Medical Center, Philadelphia, Pennsylvania, USAAbstract: Hypertension is the most significant risk factor for death worldwide. Approximately 30%–40% of affected individuals have coexisting obstructive sleep apnea (OSA, a disorder resulting from the upper airway’s inability to remain patent during sleep. A causal relationship between OSA and hypertension has been demonstrated. Blunting or elimination of normal blood pressure (BP dipping during sleep is commonly seen in OSA patients, with corresponding increases in daytime BP. This dipping is clinically salient, because it is associated with the end-organ damage seen with chronic hypertension, such as cardiovascular, renal, and cerebrovascular disease. African-Americans are at greatest risk for non-dipping and end-organ damage. Rapidly fluctuating changes in sympathetic tone, intrathoracic pressure, oxyhemoglobin saturation, and carbon dioxide levels are all thought to play a role in acute and chronic BP elevation. Individuals with preexisting hypertension are most susceptible to OSA’s BP-raising effects. First-line therapy for OSA includes continuous positive airway pressure (CPAP delivered via a mask interface. Patients who show the greatest BP declines while using CPAP are more likely to be those who have at least moderate OSA, adhere to therapy, have preexisting hypertension, and whose blood vessels retain reversibility in disease-related remodeling. Given the heavy burden OSA-related hypertension places on the healthcare system, prevention, early detection, and prompt intervention should be the goals for all affected individuals.Keywords: obstructive sleep apnea (OSA, hypertension, nocturnal dipping, continuous positive airway pressure (CPAP

  9. Effects of sleep disruption and high fat intake on glucose metabolism in mice.

    Science.gov (United States)

    Ho, Jacqueline M; Barf, R Paulien; Opp, Mark R

    2016-06-01

    Poor sleep quality or quantity impairs glycemic control and increases risk of disease under chronic conditions. Recovery sleep may offset adverse metabolic outcomes of accumulated sleep debt, but the extent to which this occurs is unclear. We examined whether recovery sleep improves glucose metabolism in mice subjected to prolonged sleep disruption, and whether high fat intake during sleep disruption exacerbates glycemic control. Adult male C57BL/6J mice were subjected to 18-h sleep fragmentation daily for 9 days, followed by 1 day of recovery. During sleep disruption, one group of mice was fed a high-fat diet (HFD) while another group was fed standard laboratory chow. Insulin sensitivity and glucose tolerance were assessed by insulin and glucose tolerance testing at baseline, after 3 and 7 days of sleep disruption, and at the end of the protocol after 24h of undisturbed sleep opportunity (recovery). To characterize changes in sleep architecture that are associated with sleep debt and recovery, we quantified electroencephalogram (EEG) recordings during sleep fragmentation and recovery periods from an additional group of mice. We now report that 9 days of 18-h daily sleep fragmentation significantly reduces rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS). Mice respond with increases in REMS, but not NREMS, during the daily 6-h undisturbed sleep opportunity. However, both REMS and NREMS increase significantly during the 24-h recovery period. Although sleep disruption alone has no effect in this protocol, high fat feeding in combination with sleep disruption impairs glucose tolerance, effects that are reversed by recovery sleep. Insulin sensitivity modestly improves after 3 days of sleep fragmentation and after 24h of recovery, with significantly greater improvements in mice exposed to HFD during sleep disruption. Improvements in both glucose tolerance and insulin sensitivity are associated with NREMS rebound, raising the possibility that this

  10. Pressure vessel failure at high internal pressure

    International Nuclear Information System (INIS)

    Laemmer, H.; Ritter, B.

    1995-01-01

    A RPV failure due to plastic instability was investigated using the ABAQUS finite element code together with a material model of thermal plasticity for large deformations. Not only rotational symmetric temperature distributions were studied, but also 'hot spots'. Calculations show that merely by the depletion of strength of the material - even at internal wall temperatures well below the melting point of the fuel elements of about 2000/2400 C - the critical internal pressure can decrease to values smaller than the operational pressure of 16 Mpa. (orig.)

  11. [Comparison of different continuous positive airway pressure titration methods for obstructive sleep apnea hypopnea syndrome].

    Science.gov (United States)

    Li, Jingjing; Ye, Jingying; Zhang, Peng; Kang, Dan; Cao, Xin; Zhang, Yuhuan; Ding, Xiu; Zheng, Li; Li, Hongguang; Bian, Qiuli

    2014-10-01

    To explore whether there were differences between the results of automatic titration and the results of manual titration for positive airway pressure treatment in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and its influencing factors, the results might provide a theoretical basis for the rational use of two pressure titration methods. Sixty one patients with OSAHS were included in this study. All patients underwent a manual titration and an automatic titration within one week. The clinical informations, polysomnography data, and the results of both two titration of all patients were obtained for analysis. The overall apnea/hypopnea index was (63.1 ± 17.7)/h, with a range of 14.9/h to 110.4/h. The treatment pressure of manual titration was (8.4 ± 2.1) cmH(2)O, which was significantly lower than the treatment pressure of automatic titration, (11.5 ± 2.7) cmH(2)O (t = -9.797, P titration and manual titration), it was found that the pressure of automatic titration was significantly higher in patients with a ΔP > 3 cmH(2)O than in patients with a ΔP ≤ 3 cmH(2)O, which was (13.3 ± 2.3) cmH(2)O vs (10.0 ± 2.0) cmH(2)O (t = -6.159, P titration between these two groups, which was (8.6 ± 2.4) cmH(2)O vs (8.3 ± 2.0)cmH(2)O (P > 0.05). There was no significant difference in age, body mass index, neck circumference, abdomen circumference, apnea hypopnea index, and arterial oxygen saturation between these two groups. The treatment pressure of automatic titration is usually higher than that of manual titration. For patients with a high treatment pressure which is derived from automatic titration, a suggestion about manual titration could be given to decrease the potential treatment pressure of continuous positive airway pressure, which may be helpful in improving the comfortableness and the compliance of this treatment.

  12. Impact of microarousal associated with increased negative esophageal pressure in sleep-disordered breathing.

    Science.gov (United States)

    Sukegawa, Mayo; Noda, Akiko; Yasuda, Yoshinari; Nakata, Seiichi; Sugiura, Tatsuki; Miyata, Seiko; Honda, Kumiko; Hasegawa, Yoshinori; Nakashima, Tsutomu; Koike, Yasuo

    2009-11-01

    "Microarousals" during sleep have not been analyzed systematically. We investigated the importance of "microarousals" (lasting 1.5-3 s). Standard polysomnography including esophageal pressure (Pes) assessment was performed on ten patients (aged 54.0 +/- 5.0 years) with respiratory effort-related arousal > or =5/h. We measured the number of arousals per hour (American Sleep Disorders Association (ASDA) arousal index) and the number of microarousals lasting 1.5-3 s per hour (mASDA arousal index). On the night after the baseline sleep study, we performed overnight continuous positive airway pressure (CPAP) titration. mASDA arousals, characterized by lower Pes values, were observed more frequently in patients with sleep-disordered breathing. The Pes results did not differ significantly between ASDA and mASDA arousals (-15.6 +/- -5.0 vs -15.0 +/- -4.4 cmH(2)O). mASDA arousals were significantly improved by CPAP treatment (mASDA arousals, 82.6 +/- 60.1 vs 6.0 +/- 1.4/h). mASDA arousals were characterized by an increase in Pes. mASDA arousals are thus key to our understanding of clinical manifestations in patients with sleep-disordered breathing.

  13. Computer simulation at high pressure

    International Nuclear Information System (INIS)

    Alder, B.J.

    1977-11-01

    The use of either the Monte Carlo or molecular dynamics method to generate equations-of-state data for various materials at high pressure is discussed. Particular emphasis is given to phase diagrams, such as the generation of various types of critical lines for mixtures, melting, structural and electronic transitions in solids, two-phase ionic fluid systems of astrophysical interest, as well as a brief aside of possible eutectic behavior in the interior of the earth. Then the application of the molecular dynamics method to predict transport coefficients and the neutron scattering function is discussed with a view as to what special features high pressure brings out. Lastly, an analysis by these computational methods of the measured intensity and frequency spectrum of depolarized light and also of the deviation of the dielectric measurements from the constancy of the Clausius--Mosotti function is given that leads to predictions of how the electronic structure of an atom distorts with pressure

  14. Anxiety: A Cause of High Blood Pressure?

    Science.gov (United States)

    ... of high blood pressure? Can anxiety cause high blood pressure? Answers from Sheldon G. Sheps, M.D. Anxiety doesn't cause long-term high blood pressure (hypertension). But episodes of anxiety can cause dramatic, ...

  15. African Americans and High Blood Pressure

    Science.gov (United States)

    ANSWERS by heart Lifestyle + Risk Reduction High Blood Pressure What About African Americans and High Blood Pressure? African Americans in the U.S. have a higher prevalence of high blood pressure (HBP) than ...

  16. High Blood Pressure: Medicines to Help You

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women High Blood Pressure--Medicines to Help You Share Tweet Linkedin Pin ... Click here for the Color Version (PDF 533KB) High blood pressure is a serious illness. High blood pressure is ...

  17. High-pressure sodium lamp

    NARCIS (Netherlands)

    1996-01-01

    A high pressure sodium lamp of the invention is provided with a discharge vessel (20) which is enclosed with intervening space (1) by an outer bulb (10), which space contains a gas-fill with at least 70 mol. % nitrogen gas. Electrodes (30a, 30b) are positioned in the discharge vessel (20) and are

  18. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink

    2016-01-01

    In this project high-pressure single crystal X-ray diffraction has been combined with quantitative energy calculations to probe the energy landscape of three hydroquinone clathrates enclosing different guest molecules. The simplicity of the hydroquinone clathrate structures together with their st...

  19. High-pressure water facility

    Science.gov (United States)

    2006-01-01

    NASA Test Operations Group employees, from left, Todd Pearson, Tim Delcuze and Rodney Wilkinson maintain a water pump in Stennis Space Center's high-pressure water facility. The three were part of a group of employees who rode out Hurricane Katrina at the facility and helped protect NASA's rocket engine test complex.

  20. Vital Signs - High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    2012-10-02

    In the U.S., nearly one third of the adult population have high blood pressure, the leading risk factor for heart disease and stroke - two of the nation's leading causes of death.  Created: 10/2/2012 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/17/2012.

  1. Differential sensitivity of long-sleep and short-sleep mice to high doses of cocaine.

    Science.gov (United States)

    de Fiebre, C M; Ruth, J A; Collins, A C

    1989-12-01

    The cocaine sensitivity of male and female long-sleep (LS) and short-sleep (SS) mice, which have been selectively bred for differential ethanol-induced "sleep-time," was examined in a battery of behavioral and physiological tests. Differences between these two mouse lines were subtle and were seen primarily at high doses. At high doses, SS mice were more sensitive than LS mice, particularly to cocaine-induced hypothermia; however, significant hypothermia was not seen except at doses which were very near to the seizure threshold. During a 60-min test of locomotor activity, LS mice showed greater stimulation of Y-maze activity by 20 mg/kg cocaine than SS mice. Consistent with the finding of subtle differences in sensitivity to low doses of cocaine. LS and SS mice did not differ in sensitivity to cocaine inhibition of synaptosomal uptake of [3H]-dopamine, [3H]-norepinephrine or [3H]-5-hydroxytryptamine. However, consistent with the finding of differential sensitivity to high doses of cocaine, SS mice were more sensitive to the seizure-producing effects of the cocaine and lidocaine, a local anesthetic. It is hypothesized that the differential sensitivity of these mouse lines to high doses of cocaine is due to differential sensitivity to cocaine's actions on systems that regulate local anesthetic effects. Selective breeding for differential duration of alcohol-induced "sleep-time" may have resulted in differential ion channel structure or function in these mice.

  2. High Pressure Treatment in Foods

    Science.gov (United States)

    Torres Bello, Edwin Fabian; González Martínez, Gerardo; Klotz Ceberio, Bernadette F.; Rodrigo, Dolores; Martínez López, Antonio

    2014-01-01

    High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance. PMID:28234332

  3. High Pressure Treatment in Foods

    Directory of Open Access Journals (Sweden)

    Edwin Fabian Torres Bello

    2014-08-01

    Full Text Available High hydrostatic pressure (HHP, a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional. Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance.

  4. Phase transitions in solids under high pressure

    CERN Document Server

    Blank, Vladimir Davydovich

    2013-01-01

    Phase equilibria and kinetics of phase transformations under high pressureEquipment and methods for the study of phase transformations in solids at high pressuresPhase transformations of carbon and boron nitride at high pressure and deformation under pressurePhase transitions in Si and Ge at high pressure and deformation under pressurePolymorphic α-ω transformation in titanium, zirconium and zirconium-titanium alloys Phase transformations in iron and its alloys at high pressure Phase transformations in gallium and ceriumOn the possible polymorphic transformations in transition metals under pressurePressure-induced polymorphic transformations in АIBVII compoundsPhase transformations in AIIBVI and AIIIBV semiconductor compoundsEffect of pressure on the kinetics of phase transformations in iron alloysTransformations during deformation at high pressure Effects due to phase transformations at high pressureKinetics and hysteresis in high-temperature polymorphic transformations under pressureHysteresis and kineti...

  5. Sleep disorders in high school and pre-university students

    Directory of Open Access Journals (Sweden)

    Célia R.S. Rocha

    2010-12-01

    Full Text Available Adolescence is a period in which youngsters have to make choices such as applying for university. The selection process is competitive, and it brings distress and anxiety, risk factors for the appearance of sleep disorders. OBJECTIVE: To verify the occurrence of sleep disorders in third-year high school and pre-university students. METHOD: This cross-sectional descriptive study comprised a sample of 529 students (M=241, F=288 from three public schools, four private schools and two pre-university courses - a middle-class neighborhood in the city of São Paulo - aged between 16 and 19 years old. We used the Pittsburgh Sleep Quality Index (PSQI - a standardized questionnaire. RESULTS: The participants (52.9% took about 30 minutes to fall asleep, with an average of 306.4 minutes asleep, moderate daytime sleepiness (n=243, 45.9% and indisposition (n=402, 75.9% to develop the activities. The scores (M and F were similar regarding problems that affect sleep. CONCLUSION: The investigated population showed sleep disorders and poor sleep quality.

  6. Sleep disorders in high school and pre-university students.

    Science.gov (United States)

    Rocha, Célia R S; Rossini, Sueli; Reimão, Rubens

    2010-12-01

    Adolescence is a period in which youngsters have to make choices such as applying for university. The selection process is competitive, and it brings distress and anxiety, risk factors for the appearance of sleep disorders. To verify the occurrence of sleep disorders in third-year high school and pre-university students. This cross-sectional descriptive study comprised a sample of 529 students (M=241, F=288) from three public schools, four private schools and two pre-university courses - a middle-class neighborhood in the city of São Paulo - aged between 16 and 19 years old. We used the Pittsburgh Sleep Quality Index (PSQI) - a standardized questionnaire. The participants (52.9%) took about 30 minutes to fall asleep, with an average of 306.4 minutes asleep, moderate daytime sleepiness (n=243, 45.9%) and indisposition (n=402, 75.9%) to develop the activities. The scores (M and F) were similar regarding problems that affect sleep. The investigated population showed sleep disorders and poor sleep quality.

  7. [Investigation on sleep status of college and high school students].

    Science.gov (United States)

    Chen, Wei; Shen, Yue-di; Chen, Rong; Ding, Guo-xian

    2005-01-01

    To investigate the sleep status of college and high schools students. Pittsburgh sleep quality index (PSQI) and self-manufactured questionnaires about siesta habits were used as tools. Three groups of students from medical college (MC), senior high school (SS) and junior high school (JS) were surveyed. In the group MC, SS and JS, the occurrence rates of sleep disorders were 27%, 62% and 54%, respectively, and in which the appearance rates of insomnia were 17%, 19% and 19%, longing for sleep were 10%, 43% and 35% respectively. And there were no significant difference between schoolboy and schoolgirl. The occurrence rates of slack breathing were different (5/155, 1/154) significantly between group SS and JS. The distinct differences also were found in group JS and MC, in which students felt hot (10/155, 1/122) and in all the three groups, in which students felt sleepy (55/155, 62/154, 13/122) whereas the difference of sleepy between group SS and JS was comparatively distinct (55/155, 62/154). Significant differences were also found between group JS and SS, MC in average sleep time of (7.65 +/- 0.87) hours, (7.16 +/- 0.83) hours, and (7.10 +/- 0.57) hours. The time of falling asleep (median 15 min, 10 min, 20 min) and siesta habit (8/155, 19/154, 75/122) among group MC and SS, JS were different respectively and markedly, whereas siesta habit differences between group SS and JS were comparatively distinct (8/155, 19/154). Students in high school showed higher rate of longing for sleep, and this implicated they fall short of sleep time greatly and siesta could improve their sleepy signs.

  8. Propofol Anesthesia and Sleep: A High-Density EEG Study

    Science.gov (United States)

    Murphy, Michael; Bruno, Marie-Aurelie; Riedner, Brady A.; Boveroux, Pierre; Noirhomme, Quentin; Landsness, Eric C.; Brichant, Jean-Francois; Phillips, Christophe; Massimini, Marcello; Laureys, Steven; Tononi, Giulio; Boly, Melanie

    2011-01-01

    Study Objectives: The electrophysiological correlates of anesthetic sedation remain poorly understood. We used high-density electroencephalography (hd-EEG) and source modeling to investigate the cortical processes underlying propofol anesthesia and compare them to sleep. Design: 256-channel EEG recordings in humans during propofol anesthesia. Setting: Hospital operating room. Patients or Participants: 8 healthy subjects (4 males) Interventions: N/A Measurements and Results: Initially, propofol induced increases in EEG power from 12–25 Hz. Loss of consciousness (LOC) was accompanied by the appearance of EEG slow waves that resembled the slow waves of NREM sleep. We compared slow waves in propofol to slow waves recorded during natural sleep and found that both populations of waves share similar cortical origins and preferentially propagate along the mesial components of the default network. However, propofol slow waves were spatially blurred compared to sleep slow waves and failed to effectively entrain spindle activity. Propofol also caused an increase in gamma (25–40 Hz) power that persisted throughout LOC. Source modeling analysis showed that this increase in gamma power originated from the anterior and posterior cingulate cortices. During LOC, we found increased gamma functional connectivity between these regions compared to the wakefulness. Conclusions: Propofol anesthesia is a sleep-like state and slow waves are associated with diminished consciousness even in the presence of high gamma activity. Citation: Murphy M; Bruno MA; Riedner BA; Boveroux P; Noirhomme Q; Landsness EC; Brichant JF; Phillips C; Massimini M; Laureys S; Tononi G; Boly M. Propofol anesthesia and sleep: a high-density EEG study. SLEEP 2011;34(3):283-291. PMID:21358845

  9. Continuous positive airway pressure for the treatment of obstructive sleep apnea.

    Science.gov (United States)

    Nurwidya, Fariz; Susanto, Agus Dwi; Juzar, Dafsah A; Kobayashi, Isao; Yunus, Faisal

    2016-01-01

    Obstructive sleep apnea (OSA) is a recurrent episode of partial or complete upper airway obstruction during sleep despite ongoing respiratory efforts and is implicated as the risk factor of cardiovascular disease. The OSA syndrome is typified by recurring partial or total occlusion of the pharynx, sleep fragmentation, episodes of gasping, and, eventually, daytime sleepiness. If it is left untreated, OSA syndrome can cause hypertension, coronary artery disease congestive heart disease, insulin resistance and death. In this review, we describe the pathogenesis and diagnosis of OSA. We also focused on the continuous positive airway pressure (CPAP) as the main therapy for OSA. CPAP has been shown to provide benefit for not only respiratory system, but also for cardiovascular system and metabolic system. Finally, we discussed briefly about the issue of adherence of using CPAP that could contribute to lower compliant in patient with OSA.

  10. High Blood Pressure: Unique to Older Adults

    Science.gov (United States)

    ... our e-newsletter! Aging & Health A to Z High Blood Pressure Hypertension Unique to Older Adults This section provides ... Pressure Targets are Different for Very Old Adults High blood pressure (also called hypertension) increases your chance of having ...

  11. Prevalence of insufficient, borderline, and optimal hours of sleep among high school students - United States, 2007.

    Science.gov (United States)

    Eaton, Danice K; McKnight-Eily, Lela R; Lowry, Richard; Perry, Geraldine S; Presley-Cantrell, Letitia; Croft, Janet B

    2010-04-01

    We describe the prevalence of insufficient, borderline, and optimal sleep hours among U.S. high school students on an average school night. Most students (68.9%) reported insufficient sleep, whereas few (7.6%) reported optimal sleep. The prevalence of insufficient sleep was highest among female and black students, and students in grades 11 and 12. Published by Elsevier Inc.

  12. Effects of exercise timing on sleep architecture and nocturnal blood pressure in prehypertensives

    Directory of Open Access Journals (Sweden)

    Fairbrother K

    2014-12-01

    Full Text Available Kimberly Fairbrother,1 Ben Cartner,1 Jessica R Alley,1 Chelsea D Curry,1, David L Dickinson,2 David M Morris,1 Scott R Collier1 1Vascular Biology and Autonomic Studies Laboratory, Department of Health and Exercise Science, 2Department of Economics, Appalachian State University, Boone, NC, USA Background: During nocturnal sleep, blood pressure (BP “dips” compared to diurnal BP, reducing stress on the cardiovascular system. Both the hypotensive response elicited by acute aerobic exercise and sleep quality can impact this dipping response. Purpose: The purpose of this study was to investigate the effects of aerobic exercise timing on circadian BP changes and sleep architecture. Materials and methods: Twenty prehypertensive subjects completed the study. During four test sessions, participants first completed a graded exercise test to exhaustion and then performed 30 minutes of treadmill exercise at 7 am (7A, 1 pm (1P, and 7 pm (7P in a random, counterbalanced order at 65% of the heart rate obtained at peak oxygen uptake. An ambulatory cuff was used to monitor BP responses during 24 hours following exercise, and an ambulatory sleep-monitoring headband was worn during sleep following each session. Results: Aerobic exercise at 7A invoked a greater dip in nocturnal systolic BP than exercise at 1P or 7P, although the greatest dip in nocturnal diastolic BP occurred following 7P. Compared to 1P, 7A also invoked greater time spent in deep sleep. Conclusion: These data indicate that early morning may be the most beneficial time to engage in aerobic exercise to enhance nocturnal BP changes and quality of sleep. Keywords: nocturnal dipping, prehypertension, aerobic exercise

  13. Treatment of obstructive sleep apnea syndrome with nasal positive airway pressure improves golf performance.

    Science.gov (United States)

    Benton, Marc L; Friedman, Neil S

    2013-12-15

    Obstructive sleep apnea syndrome (OSAS) is associated with impairment of cognitive function, and improvement is often noted with treatment. Golf is a sport that requires a range of cognitive skills. We evaluated the impact of nasal positive airway pressure (PAP) therapy on the handicap index (HI) of golfers with OSAS. Golfers underwent a nocturnal polysomnogram (NPSG) to determine whether they had significant OSAS (respiratory disturbance index > 15). Twelve subjects with a positive NPSG were treated with PAP. HI, an Epworth Sleepiness Scale (ESS), and sleep questionnaire (SQ) were submitted upon study entry. After 20 rounds of golf on PAP treatment, the HI was recalculated, and the questionnaires were repeated. A matched control group composed of non-OSAS subjects was studied to assess the impact of the study construct on HI, ESS, and SQ. Statistical comparisons between pre- and post-PAP treatment were calculated. The control subjects demonstrated no significant change in HI, ESS, or SQ during this study, while the OSAS group demonstrated a significant drop in average HI (11.3%, p = 0.01), ESS, (p = 0.01), and SQ (p = 0.003). Among the more skilled golfers (defined as HI ≤ 12), the average HI dropped by an even greater degree (31.5%). Average utilization of PAP was 91.4% based on data card reporting. Treatment of OSAS with PAP enhanced performance in golfers with this condition. Treatment adherence was unusually high in this study. Non-medical performance improvement may be a strong motivator for selected subjects with OSAS to seek treatment and maximize adherence.

  14. High pressure effects on fruits and vegetables

    OpenAIRE

    Timmermans, R.A.H.; Matser, A.M.

    2016-01-01

    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure treatment can be used for product modification through pressure gelatinization of starch and pressure denaturation of proteins. Key pressure–thermal treatment effects on vitamin, enzymes, flavor, co...

  15. Brillouin scattering at high pressures

    International Nuclear Information System (INIS)

    Grimsditch, M.; Polian, A.

    1988-02-01

    Technical advances which have made Brillouin scattering a useful tool in high pressure diamond anvil cell (DAC) studies, viz. multipassing and tandem operation of Fabry-Perot interferometers, are reviewed. Experimental aspects, such as allowed scattering geometries, are outlined and the data analysis required to transform Brillouin spectra into sound velocities and elastic constants is presented. Experimental results on H 2 , N 2 , Ar, and He are presented, and the close relationship between the Brillouin scattering results and equations of state is highlighted

  16. Oral appliance therapy versus nasal continuous positive airway pressure in obstructive sleep apnoea syndrome: a randomised, placebo-controlled trial on self-reported symptoms of common sleep disorders and sleep-related problems.

    Science.gov (United States)

    Nikolopoulou, M; Byraki, A; Ahlberg, J; Heymans, M W; Hamburger, H L; De Lange, J; Lobbezoo, F; Aarab, G

    2017-06-01

    Obstructive sleep apnoea syndrome (OSAS) is associated with several sleep disorders and sleep-related problems. Therefore, the aim of this study was to compare the effects of a mandibular advancement device (MAD) with those of nasal continuous positive airway pressure (nCPAP) on self-reported symptoms of common sleep disorders and sleep-related problems in mild and moderate OSAS patients. In this randomised placebo-controlled trial, sixty-four OSAS patients (52·0 ± 9·6 years) were randomly assigned to an MAD, nCPAP or an intra-oral placebo appliance in a parallel design. All participants filled out the validated Dutch Sleep Disorders Questionnaire (SDQ) twice: one before treatment and one after six months of treatment. With 88 questions, thirteen scales were constructed, representing common sleep disorders and sleep-related problems. Linear mixed model analyses were performed to study differences between the groups for the different SDQ scales over time. The MAD group showed significant improvements over time in symptoms corresponding with 'insomnia', 'excessive daytime sleepiness', 'psychiatric sleep disorder', 'periodic limb movements', 'sleep apnoea', 'sleep paralysis', 'daytime dysfunction', 'hypnagogic hallucinations/dreaming', 'restless sleep', 'negative conditioning' and 'automatic behaviour' (range of P values: 0·000-0·014). These improvements in symptoms were, however, not significantly different from the improvements in symptoms observed in the nCPAP and placebo groups (range of P values: 0·090-0·897). It can be concluded that there is no significant difference between MAD and nCPAP in their positive effects on self-reported symptoms of common sleep disorders and sleep-related problems in mild and moderate OSAS patients. These beneficial effects may be a result of placebo effects. © 2017 John Wiley & Sons Ltd.

  17. High pressure effects on fruits and vegetables

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Matser, A.M.

    2016-01-01

    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure

  18. Clinical predictors of central sleep apnea evoked by positive airway pressure titration.

    Science.gov (United States)

    Moro, Marilyn; Gannon, Karen; Lovell, Kathy; Merlino, Margaret; Mojica, James; Bianchi, Matt T

    2016-01-01

    Treatment-emergent central sleep apnea (TECSA), also called complex apnea, occurs in 5%-15% of sleep apnea patients during positive airway pressure (PAP) therapy, but the clinical predictors are not well understood. The goal of this study was to explore possible predictors in a clinical sleep laboratory cohort, which may highlight those at risk during clinical management. We retrospectively analyzed 728 patients who underwent PAP titration (n=422 split-night; n=306 two-night). Demographics and self-reported medical comorbidities, medications, and behaviors as well as standard physiological parameters from the polysomnography (PSG) data were analyzed. We used regression analysis to assess predictors of binary presence or absence of central apnea index (CAI) ≥5 during split-night PSG (SN-PSG) versus full-night PSG (FN-PSG) titrations. CAI ≥5 was present in 24.2% of SN-PSG and 11.4% of FN-PSG patients during titration. Male sex, maximum continuous positive airway pressure, and use of bilevel positive airway pressure were predictors of TECSA, and rapid eye movement dominance was a negative predictor, for both SN-PSG and FN-PSG patients. Self-reported narcotics were a positive predictor of TECSA, and the time spent in stage N2 sleep was a negative predictor only for SN-PSG patients. Self-reported history of stroke and the CAI during the diagnostic recording predicted TECSA only for FN-PSG patients. Clinical predictors of treatment-evoked central apnea spanned demographic, medical history, sleep physiology, and titration factors. Improved predictive models may be increasingly important as diagnostic and therapeutic modalities move away from the laboratory setting, even as PSG remains the gold standard for characterizing primary central apnea and TECSA.

  19. Efficacy of daytime continuous positive airway pressure titration in severe obstructive sleep apnoea.

    Science.gov (United States)

    Rudkowski, J C; Verschelden, P; Kimoff, R J

    2001-09-01

    The aim of this study was to evaluate manual nasal continuous positive airway pressure (nCPAP) titration during daytime polysomnography compared with conventional overnight titration for patients with severe obstructive sleep apnoea. Thirty-two patients who underwent daytime titration were retrospectively matched (for age, sex, body mass index and apnoea/hypopnoea index (AHI)) to a group titrated overnight during the same period. Successful titration was defined as the identification of the nCPAP level (effective nCPAP (Peff)) required to eliminate respiratory events during all sleep stages. After 3 months of therapy on nCPAP at Peff, nCPAP utilization history was obtained and a group of patients underwent a repeat polysomnogram (PSG) and completed a follow-up Epworth Sleepiness Scale (ESS) score. Initial titration was successful in 91% of daytime patients and 91% of overnight patients. The success of daytime titration was not related to diagnostic AHI or ESS score. Subjective nCPAP utilization was statistically similar in both groups. On the follow-up PSG, there were no significant differences between daytime (n=11) and overnight (n=11) patients in measures of sleep quality or respiratory disturbance. Both groups demonstrated similar and significant improvements in ESS score. These findings suggest that the effective nasal continuous positive airway pressure can be accurately established during daytime titration in a substantial proportion of severe, symptomatic obstructive sleep apnoea patients.

  20. Sleep spindles during a nap correlate with post sleep memory performance for highly rewarded word-pairs.

    Science.gov (United States)

    Studte, Sara; Bridger, Emma; Mecklinger, Axel

    2017-04-01

    The consolidation of new associations is thought to depend in part on physiological processes engaged during non-REM (NREM) sleep, such as slow oscillations and sleep spindles. Moreover, NREM sleep is thought to selectively benefit associations that are adaptive for the future. In line with this, the current study investigated whether different reward cues at encoding are associated with changes in sleep physiology and memory retention. Participants' associative memory was tested after learning a list of arbitrarily paired words both before and after taking a 90-min nap. During learning, word-pairs were preceded by a cue indicating either a high or a low reward for correct memory performance at test. The motivation manipulation successfully impacted retention such that memory declined to a greater extent from pre- to post sleep for low rewarded than for high rewarded word-pairs. In line with previous studies, positive correlations between spindle density during NREM sleep and general memory performance pre- and post-sleep were found. In addition to this, however, a selective positive relationship between memory performance for highly rewarded word-pairs at posttest and spindle density during NREM sleep was also observed. These results support the view that motivationally salient memories are preferentially consolidated and that sleep spindles may be an important underlying mechanism for selective consolidation. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. High Pressure Electrolyzer System Evaluation

    Science.gov (United States)

    Prokopius, Kevin; Coloza, Anthony

    2010-01-01

    This report documents the continuing efforts to evaluate the operational state of a high pressure PEM based electrolyzer located at the NASA Glenn Research Center. This electrolyzer is a prototype system built by General Electric and refurbished by Hamilton Standard (now named Hamilton Sunstrand). It is capable of producing hydrogen and oxygen at an output pressure of 3000 psi. The electrolyzer has been in storage for a number of years. Evaluation and testing was performed to determine the state of the electrolyzer and provide an estimate of the cost for refurbishment. Pressure testing was performed using nitrogen gas through the oxygen ports to ascertain the status of the internal membranes and seals. It was determined that the integrity of the electrolyzer stack was good as there were no appreciable leaks in the membranes or seals within the stack. In addition to the integrity testing, an itemized list and part cost estimate was produced for the components of the electrolyzer system. An evaluation of the system s present state and an estimate of the cost to bring it back to operational status was also produced.

  2. Paradoxical reaction of blood pressure on sleep apnoea patients treated with Positive Airway Pressure

    Directory of Open Access Journals (Sweden)

    C. Chaves Loureiro

    2011-03-01

    Full Text Available Introduction: Obstructive Sleep Apnoea Syndrome (OSAS patients may develop hypertension and Positive Airway Pressure (PAP is an effective treatment in blood pressure (BP control. Objectives: Analyse a hypertensive OSAS population with unexpected BP rise after PAP usage and verify correlations between BP rise, either with OSAS severity index or nocturnal ventilatory support compliance. Methods: Descriptive, retrospective analysis of 30 patients with PAP treated OSA, for one year, on average, and with previous controlled hypertension, who developed a rise in BP, defined as augmentation of > 5 mmHg in systolic (SBP and/or diastolic BP (DBP, after PAP usage. Co-relational analysis of BP increase, with OSAS severity indexes and therapy compliance, using Pearson coefficient. Results: Of 508 consecutive patients followed in our Department, treated with nocturnal ventilatory support, 30 evolved with BP rise after initiating treatment (age 58 ± 10.8 years; Apnoea-Hypopnoea Index [AHI], 46.1 ± 18.68. After PAP usage, mean blood pressure (MBP, Systolic BP (SBP and Diastolic BP (DBP variation was 16 ± 15 mmHg, 20 ± 25 mmHg and 6 ± 19.4 mmHg, respectively. No patient showed significant BMI increase. Epworth Sleepiness Scale (ESS value decreased 8.9 ± 5.48 points. MBP, SBP and DBP variations were not correlated with P90/P95, residual AHI, leaks or PAP compliance. Conclusions: No specific characteristics were identified in the group who developed a rise in BP with PAP usage. No correlations were found between rises in BP and OSAS severity indexes or PAP compliance. Neither BMI nor variation in wakefulness status explained the rise in BP. Studies relate polymorphisms of b1-adrenoreceptors with different BP responses to ventilatory support. More studies are needed to clarify the cause of this paradoxical response. Resumo: Introdução: Doentes com síndrome de Apneia Obstrutiva do Sono (SAOS podem desenvolver hipertensão arterial (HTA sendo a

  3. High-density EEG characterization of brain responses to auditory rhythmic stimuli during wakefulness and NREM sleep.

    Science.gov (United States)

    Lustenberger, Caroline; Patel, Yogi A; Alagapan, Sankaraleengam; Page, Jessica M; Price, Betsy; Boyle, Michael R; Fröhlich, Flavio

    2018-04-01

    Auditory rhythmic sensory stimulation modulates brain oscillations by increasing phase-locking to the temporal structure of the stimuli and by increasing the power of specific frequency bands, resulting in Auditory Steady State Responses (ASSR). The ASSR is altered in different diseases of the central nervous system such as schizophrenia. However, in order to use the ASSR as biological markers for disease states, it needs to be understood how different vigilance states and underlying brain activity affect the ASSR. Here, we compared the effects of auditory rhythmic stimuli on EEG brain activity during wake and NREM sleep, investigated the influence of the presence of dominant sleep rhythms on the ASSR, and delineated the topographical distribution of these modulations. Participants (14 healthy males, 20-33 years) completed on the same day a 60 min nap session and two 30 min wakefulness sessions (before and after the nap). During these sessions, amplitude modulated (AM) white noise auditory stimuli at different frequencies were applied. High-density EEG was continuously recorded and time-frequency analyses were performed to assess ASSR during wakefulness and NREM periods. Our analysis revealed that depending on the electrode location, stimulation frequency applied and window/frequencies analysed the ASSR was significantly modulated by sleep pressure (before and after sleep), vigilance state (wake vs. NREM sleep), and the presence of slow wave activity and sleep spindles. Furthermore, AM stimuli increased spindle activity during NREM sleep but not during wakefulness. Thus, (1) electrode location, sleep history, vigilance state and ongoing brain activity needs to be carefully considered when investigating ASSR and (2) auditory rhythmic stimuli during sleep might represent a powerful tool to boost sleep spindles. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. High pressure research at CHESS

    International Nuclear Information System (INIS)

    Brister, K.

    1992-01-01

    Since February 1990 there has been a dedicated high pressure line at the Cornell High Energy Synchrotron Source (CHESS). This facility provides X-ray instrumentation for energy dispersive X-ray diffraction and Laue diffraction using diamond anvil cells. Both hard-bend magnet and wiggler radiation are available as well as focused monochromatic radiation. In addition, support instrumentation is also available; a ruby system, laser heating, sample loading, and data analysis software. Experienced users need only to bring their diamond anvil cells and samples and can leave with the initial data analysis finished. Research using diamond anvil cells will be introduced and the facility will be described. Some of the diamond anvil cell research done at CHESS will be reviewed, including crystalline to amorphous transitions (R.R. Winters et al., Chem. Phys, in press), properties of C 6 0 under stress (S.J. Duclos et al., Nature 351 (1991) 380), deep earthquakes (T.C. Wu et al., submitted to J. Geophys. Res.)l, and reaching pressures of the center of Earth (A.L. Ruoff et al., Rev. Sci. Instr. 61 (1990) 3830). (orig.)

  5. Clinical predictors of central sleep apnea evoked by positive airway pressure titration

    Directory of Open Access Journals (Sweden)

    Moro M

    2016-07-01

    Full Text Available Marilyn Moro,1 Karen Gannon,1 Kathy Lovell,1 Margaret Merlino,1 James Mojica,2 Matt T Bianchi,1,3 1Neurology Department, 2Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA; 3Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA Purpose: Treatment-emergent central sleep apnea (TECSA, also called complex apnea, occurs in 5%–15% of sleep apnea patients during positive airway pressure (PAP therapy, but the clinical predictors are not well understood. The goal of this study was to explore possible predictors in a clinical sleep laboratory cohort, which may highlight those at risk during clinical management.Methods: We retrospectively analyzed 728 patients who underwent PAP titration (n=422 split night; n=306 two-night. Demographics and self-reported medical comorbidities, medications, and behaviors as well as standard physiological parameters from the polysomnography (PSG data were analyzed. We used regression analysis to assess predictors of binary presence or absence of central apnea index (CAI ≥5 during split PSG (SN-PSG versus full-night PSG (FN-PSG titrations.Results: CAI ≥5 was present in 24.2% of SN-PSG and 11.4% of FN-PSG patients during titration. Male sex, maximum continuous positive airway pressure, and use of bilevel positive airway pressure were predictors of TECSA, and rapid eye movement dominance was a negative predictor, for both SN-PSG and FN-PSG patients. Self-reported narcotics were a positive predictor of TECSA, and the time spent in stage N2 sleep was a negative predictor only for SN-PSG patients. Self-reported history of stroke and the CAI during the diagnostic recording predicted TECSA only for FN-PSG patients.Conclusion: Clinical predictors of treatment-evoked central apnea spanned demographic, medical history, sleep physiology, and titration factors. Improved predictive models may be increasingly important as diagnostic and therapeutic modalities move away from the

  6. A Novel Therapy for Chronic Sleep-Onset Insomnia: A Retrospective, Nonrandomized Controlled Study of Auto-Adjusting, Dual-Level, Positive Airway Pressure Technology.

    Science.gov (United States)

    Krakow, Barry; Ulibarri, Victor A; McIver, Natalia D; Nadorff, Michael R

    2016-09-29

    Evidence indicates that behavioral or drug therapy may not target underlying pathophysiologic mechanisms for chronic insomnia, possibly due to previously unrecognized high rates (30%-90%) of sleep apnea in chronic insomnia patients. Although treatment studies with positive airway pressure (PAP) demonstrate decreased severity of chronic sleep maintenance insomnia in patients with co-occurring sleep apnea, sleep-onset insomnia has not shown similar results. We hypothesized advanced PAP technology would be associated with decreased sleep-onset insomnia severity in a sample of predominantly psychiatric patients with comorbid sleep apnea. We reviewed charts of 74 severe sleep-onset insomnia patients seen from March 2011 to August 2015, all meeting American Academy of Sleep Medicine Work Group criteria for a chronic insomnia disorder and all affirming behavioral and psychological origins for insomnia (averaging 10 of 18 indicators/patient), as well as averaging 2 or more psychiatric symptoms or conditions: depression (65.2%), anxiety (41.9%), traumatic exposure (35.1%), claustrophobia (29.7%), panic attacks (28.4%), and posttraumatic stress disorder (20.3%). All patients failed continuous or bilevel PAP and were manually titrated with auto-adjusting PAP modes (auto-bilevel and adaptive-servo ventilation). At 1-year follow-up, patients were compared through nonrandom assignment on the basis of a PAP compliance metric of > 20 h/wk (56 PAP users) versus insomnia severity (Hedges' g = 1.72) and sleep-onset insomnia (g = 2.07) compared to partial users (g = 1.04 and 0.91, respectively). Both global and sleep-onset insomnia severity decreased below moderate levels in PAP users compared to partial users whose outcomes persisted at moderately severe levels. In a nonrandomized controlled retrospective study, advanced PAP technology (both auto-bilevel and adaptive servo-ventilation) were associated with large decreases in insomnia severity for sleep-onset insomnia patients who

  7. Obstructive Sleep Apnea

    Medline Plus

    Full Text Available ... can also invite bacteria that lead to gum disease. Click here to find out more. Obstructive Sleep Apnea (OSA) Download Download the ebook for further information Obstructive sleep ... high blood pressure, heart disease and decreased libido. In addition, OSA causes daytime ...

  8. High-pressure microhydraulic actuator

    Science.gov (United States)

    Mosier, Bruce P [San Francisco, CA; Crocker, Robert W [Fremont, CA; Patel, Kamlesh D [Dublin, CA

    2008-06-10

    Electrokinetic ("EK") pumps convert electric to mechanical work when an electric field exerts a body force on ions in the Debye layer of a fluid in a packed bed, which then viscously drags the fluid. Porous silica and polymer monoliths (2.5-mm O.D., and 6-mm to 10-mm length) having a narrow pore size distribution have been developed that are capable of large pressure gradients (250-500 psi/mm) when large electric fields (1000-1500 V/cm) are applied. Flowrates up to 200 .mu.L/min and delivery pressures up to 1200 psi have been demonstrated. Forces up to 5 lb-force at 0.5 mm/s (12 mW) have been demonstrated with a battery-powered DC-DC converter. Hydraulic power of 17 mW (900 psi@ 180 uL/min) has been demonstrated with wall-powered high voltage supplies. The force and stroke delivered by an actuator utilizing an EK pump are shown to exceed the output of solenoids, stepper motors, and DC motors of similar size, despite the low thermodynamic efficiency.

  9. Nuclear magnetic resonance studies at high pressures

    International Nuclear Information System (INIS)

    Jonas, J.

    1980-01-01

    Recent advances in the field of NMR spectroscopy at high pressure are reviewed. After a brief discussion of two novel experimental techniques, the main focus of this review is on several specific studies which illustrate the versatility and power of this high pressure field. Experimental aspects of NMR measurements at high pressure and high temperature and the techniques for the high resolution NMR spectroscopy at high pressure are discussed. An overview of NMR studies of the dynamic structure of simple polyatomic liquids and hydrogen bonded liquids is followed by a discussion of high resolution spectroscopy at high pressure. Examples of NMR studies of disordered organic solids and polymers conclude the review. (author)

  10. Obstructive Sleep Apnea

    Medline Plus

    Full Text Available ... include heart attack, stroke, irregular heartbeat, high blood pressure, heart disease and decreased libido. In addition, OSA causes daytime drowsiness that can result in accidents, lost productivity and relationship problems. The National Sleep Foundation ...

  11. Positive airway pressure adherence and subthreshold adherence in posttraumatic stress disorder patients with comorbid sleep apnea

    Directory of Open Access Journals (Sweden)

    Krakow BJ

    2017-11-01

    Full Text Available Barry J Krakow,1–3 Jessica J Obando,2 Victor A Ulibarri,1,2 Natalia D McIver1,2 1Sleep & Human Health Institute, 2Maimonides Sleep Arts & Sciences, Albuquerque, 3Los Alamos Medical Center, Los Alamos, NM, USA Study objectives: Patients with comorbid posttraumatic stress disorder (PTSD and obstructive sleep apnea (OSA manifest low adherence to continuous positive airway pressure (CPAP due to fixed, pressure-induced expiratory pressure intolerance (EPI, a subjective symptom and objective sign aggravated by anxiety sensitivity and somatosensory amplification. As advanced PAP therapy modes (ie, auto-bilevel PAP [ABPAP] or adaptive servo-ventilation [ASV] may address these side effects, we hypothesized such treatment would be associated with decreased expiratory intolerance and increased adherence in posttraumatic stress patients with co-occurring OSA.Methods: We reviewed charts of 147 consecutive adult patients with moderately severe posttraumatic stress symptoms and objectively diagnosed OSA. All patients failed or rejected CPAP and were manually titrated on auto-adjusting, dual-pressure ABPAP or ASV modes in the sleep laboratory, a technique to eliminate flow limitation breathing events while resolving EPI. Patients were then prescribed either mode of therapy. Follow-up encounters assessed patient use, and objective data downloads (ODDs measured adherence.Results: Of 147 charts reviewed, 130 patients were deemed current PAP users, and 102 provided ODDs: 64 used ASV and 38 used ABPAP. ODDs yielded three groups: 59 adherent per insurance conventions, 19 subthreshold compliant partial users, and 24 noncompliant. Compliance based on available downloads was 58%, notably higher than recently reported rates in PTSD patients with OSA. Among the 19 partial users, 17 patients were minutes of PAP use or small percentages of nights removed from meeting insurance compliance criteria for PAP devices.Conclusion: Research is warranted on advanced PAP modes in

  12. High-intensity interval training improves obstructive sleep apnoea.

    Science.gov (United States)

    Karlsen, Trine; Nes, Bjarne Martens; Tjønna, Arnt Erik; Engstrøm, Morten; Støylen, Asbjørn; Steinshamn, Sigurd

    2016-01-01

    Three hours per week of vigorous physical activity is found to be associated with reduced odds of sleep-disordered breathing. To investigate whether 12 weeks of high-intensity interval training (HIIT) reduced the apnoea-hypopnea index (AHI) in obese subjects with moderate-to-severe obstructive sleep apnoea. In a prospective randomised controlled exercise study, 30 (body mass index 37±6 kg/m 2 , age 51±9 years) patients with sleep apnoea (AHI 41.5±25.3 events/hour) were randomised 1:1 to control or 12 weeks of supervised HIIT (4×4 min of treadmill running or walking at 90%-95% of maximal heart rate two times per week). In the HIIT group, the AHI was reduced by 7.5±11.6 events/hour (within-group pHIIT improved the AHI and self-reported daytime sleepiness in subjects with obese sleep apnoea without any change in the desaturation index and body weight.

  13. DASH diet to lower high blood pressure

    Science.gov (United States)

    ... patientinstructions/000770.htm DASH diet to lower high blood pressure To use the sharing features on this page, ... Hypertension. The DASH diet can help lower high blood pressure and cholesterol and other fats in your blood. ...

  14. What Is High Blood Pressure Medicine?

    Science.gov (United States)

    ... a medicine calendar. • Set a reminder on your smartphone. What types of medicine may be prescribed? One ... High Blood Pressure Medicine? What are their side effects? For many people, high blood pressure medicine can ...

  15. High blood pressure - medicine-related

    Science.gov (United States)

    Drug-induced hypertension is high blood pressure caused by using a chemical substance or medicine. ... of the arteries There are several types of high blood pressure : Essential hypertension has no cause that can be ...

  16. High blood pressure and eye disease

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000999.htm High blood pressure and eye disease To use the sharing features on this page, please enable JavaScript. High blood pressure can damage blood vessels in the retina . The ...

  17. High pressure metrology for industrial applications

    Science.gov (United States)

    Sabuga, Wladimir; Rabault, Thierry; Wüthrich, Christian; Pražák, Dominik; Chytil, Miroslav; Brouwer, Ludwig; Ahmed, Ahmed D. S.

    2017-12-01

    To meet the needs of industries using high pressure technologies, in traceable, reliable and accurate pressure measurements, a joint research project of the five national metrology institutes and the university was carried out within the European Metrology Research Programme. In particular, finite element methods were established for stress-strain analysis of elastic and nonlinear elastic-plastic deformation, as well as of contact processes in pressure-measuring piston-cylinder assemblies, and high-pressure components at pressures above 1 GPa. New pressure measuring multipliers were developed and characterised, which allow realisation of the pressure scale up to 1.6 GPa. This characterisation is based on research including measurements of material elastic constants by the resonant ultrasound spectroscopy, hardness of materials of high pressure components, density and viscosity of pressure transmitting liquids at pressures up to 1.4 GPa and dimensional measurements on piston-cylinders. A 1.6 GPa pressure system was created for operation of the 1.6 GPa multipliers and calibration of high pressure transducers. A transfer standard for 1.5 GPa pressure range, based on pressure transducers, was built and tested. Herewith, the project developed the capability of measuring pressures up to 1.6 GPa, from which industrial users can calibrate their pressure measurement devices for accurate measurements up to 1.5 GPa.

  18. High self-perceived exercise exertion before bedtime is associated with greater objectively assessed sleep efficiency.

    Science.gov (United States)

    Brand, Serge; Kalak, Nadeem; Gerber, Markus; Kirov, Roumen; Pühse, Uwe; Holsboer-Trachsler, Edith

    2014-09-01

    To assess the association between self-perceived exercise exertion before bedtime and objectively measured sleep. Fifty-two regularly exercising young adults (mean age, 19.70 years; 54% females) underwent sleep electroencephalographic recordings 1.5 h after completing moderate to vigorous exercise in the evening. Before sleeping, participants answered questions regarding degree of exertion of the exercise undertaken. Greater self-perceived exertion before bedtime was associated with higher objectively assessed sleep efficiency (r = 0.69, P associated with more deep sleep, shortened sleep onset time, fewer awakenings after sleep onset, and shorter wake duration after sleep onset. Multiple linear regression analysis showed that objective sleep efficiency was predicted by increased exercise exertion, shortened sleep onset time, increased deep sleep, and decreased light sleep. Against expectations and general recommendations for sleep hygiene, high self-perceived exercise exertion before bedtime was associated with better sleep patterns in a sample of healthy young adults. Further studies should also focus on elderly adults and adults suffering from insomnia. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. High-Flow Nasal Oxygen in Patient With Obstructive Sleep Apnea Undergoing Awake Craniotomy: A Case Report.

    Science.gov (United States)

    Wong, Jaclyn W M; Kong, Amy H S; Lam, Sau Yee; Woo, Peter Y M

    2017-12-15

    Patients with obstructive sleep apnea are frequently considered unsuitable candidates for awake craniotomy due to anticipated problems with oxygenation, ventilation, and a potentially difficult airway. At present, only a handful of such accounts exist in the literature. Our report describes the novel use of high-flow nasal oxygen therapy for a patient with moderate obstructive sleep apnea who underwent an awake craniotomy under deep sedation. The intraoperative application of high-flow nasal oxygen therapy achieved satisfactory oxygenation, maintained the partial carbon dioxide pressure within a reasonable range even during periods of deep sedation, permitted responsive patient monitoring during mapping, and provided excellent patient and surgeon satisfaction.

  20. Respiration and body movement analysis during sleep in bed using hetero-core fiber optic pressure sensors without constraint to human activity.

    Science.gov (United States)

    Nishyama, Michiko; Miyamoto, Mitsuo; Watanabe, Kazuhiro

    2011-01-01

    We describe respiration monitoring in sleep using hetero-core fiber optic pressure sensors. The proposed hetero-core fiber optic sensor is highly sensitive to macrobending as a result of the core diameter difference due to stable single-mode transmission. Pressure sensors based on hetero-core fiber optics were fabricated to have a high sensitivity to small pressure changes resulting from minute body motions, such as respiration, during sleep and large pressure changes, such as those caused by a rollover. The sensors are installed in a conventional bed. The pressure characteristic performance of all the fabricated hetero-core fiber optic pressure sensors is found to show a monotonic response with weight changes. A respiration monitoring test in seven subjects efficiently demonstrates the effective use of eight hetero-core pressure sensors installed in a bed. Additionally, even in the case of different body postures, such as lying on one's side, a slight body movement due to respiration is detected by the hetero-core pressure sensors.

  1. High-Pressure Lightweight Thrusters

    Science.gov (United States)

    Holmes, Richard; McKechnie, Timothy; Shchetkovskiy, Anatoliy; Smirnov, Alexander

    2013-01-01

    Returning samples of Martian soil and rock to Earth is of great interest to scientists. There were numerous studies to evaluate Mars Sample Return (MSR) mission architectures, technology needs, development plans, and requirements. The largest propulsion risk element of the MSR mission is the Mars Ascent Vehicle (MAV). Along with the baseline solid-propellant vehicle, liquid propellants have been considered. Similar requirements apply to other lander ascent engines and reaction control systems. The performance of current state-ofthe- art liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure. Pump-fed propulsion is suggested for a single-stage bipropellant MAV. Achieving a 90-percent stage propellant fraction is thought to be possible on a 100-kg scale, including sufficient thrust for lifting off Mars. To increase the performance of storable bipropellant rocket engines, a high-pressure, lightweight combustion chamber was designed. Iridium liner electrodeposition was investigated on complex-shaped thrust chamber mandrels. Dense, uniform iridium liners were produced on chamber and cylindrical mandrels. Carbon/carbon composite (C/C) structures were braided over iridium-lined mandrels and densified by chemical vapor infiltration. Niobium deposition was evaluated for forming a metallic attachment flange on the carbon/ carbon structure. The new thrust chamber was designed to exceed state-of-the-art performance, and was manufactured with an 83-percent weight savings. High-performance C/Cs possess a unique set of properties that make them desirable materials for high-temperature structures used in rocket propulsion components, hypersonic vehicles, and aircraft brakes. In particular, more attention is focused on 3D braided C/Cs due to their mesh-work structure. Research on the properties of C/Cs has shown that the strength of composites is strongly affected by the fiber-matrix interfacial bonding, and that weakening

  2. Evaluation of high temperature pressure sensors

    International Nuclear Information System (INIS)

    Choi, In-Mook; Woo, Sam-Yong; Kim, Yong-Kyu

    2011-01-01

    It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.

  3. Sleep duration modifies effects of free ad libitum school meals on adiposity and blood pressure

    DEFF Research Database (Denmark)

    Hjorth, Mads Fiil; Sjödin, Anders Mikael; Dalskov, Stine-Mathilde

    2016-01-01

    .03;0.38) kg, android fat mass by 0.02 (0.001;0.04) kg, waist circumference by 0.73 (0.23;1.24) cm, blood pressure by 1.5 (0.4;2.6) mmHg, fat intake by 1.1 (0.2;2.0) energy %, and decreased total physical activity by 7.2 (1.6;12.7) % (all P≤0.04), while HOMAIR and blood lipids were not modified by sleep...

  4. The effect of obstructive sleep apnea and treatment with continuous positive airway pressure on stroke rehabilitation: rationale, design and methods of the TOROS study

    NARCIS (Netherlands)

    Aaronson, Justine A.; van Bennekom, Coen A. M.; Hofman, Winni F.; van Bezeij, Tijs; van den Aardweg, Joost G.; Groet, Erny; Kylstra, Wytske A.; Schmand, Ben A.

    2014-01-01

    Obstructive sleep apnea is a common sleep disorder in stroke patients. Obstructive sleep apnea is associated with stroke severity and poor functional outcome. Continuous positive airway pressure seems to improve functional recovery in stroke rehabilitation. To date, the effect of continuous positive

  5. The effect of obstructive sleep apnea and treatment with continuous positive airway pressure on stroke rehabilitation: rationale, design and methods of the TOROS study

    NARCIS (Netherlands)

    Aaronson, J.A.; van Bennekom, C.A.M.; Hofman, W.F.; van Bezeij, T.; van den Aardweg, J.G.; Groet, E.; Kylstra, W.A.; Schmand, B.A.

    2014-01-01

    BACKGROUND: Obstructive sleep apnea is a common sleep disorder in stroke patients. Obstructive sleep apnea is associated with stroke severity and poor functional outcome. Continuous positive airway pressure seems to improve functional recovery in stroke rehabilitation. To date, the effect of

  6. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Multimedia

    2007-01-01

    To find out, the Medical Service's nurses are organising A HIGH BLOOD PRESSURE SCREENING AND PREVENTION CAMPAIGN from Monday, 26th to Thursday, 29th March 2007 at the Infirmary - Building 57 - ground floor A blood pressure test, advice, information and, if necessary, referral for specialist medical treatment will be offered to any person working on the CERN site. High blood pressure is a silent threat to health. So come and get your blood pressure checked.

  7. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Multimedia

    2007-01-01

    To find out, the Medical Service's nurses are organising A HIGH BLOOD PRESSURE SCREENING AND PREVENTION CAMPAIGN from Monday, 26th to Thursday, 29th March 2007 at the Infirmary - Building 57 - ground floor A blood pressure test, advice, information and, if necessary, referral for specialist medical treatment will be offered to any person working on the CERN site. High blood pressure is a stealth threat to health. So come and get your blood pressure checked.

  8. Natural history of treatment-emergent central sleep apnea on positive airway pressure: A systematic review.

    Science.gov (United States)

    Nigam, Gaurav; Riaz, Muhammad; Chang, Edward T; Camacho, Macario

    2018-01-01

    Treatment-emergent central sleep apnea (TECSA) is observed in some patients when they are treated with positive airway pressure (PAP) after significant resolution of the preexisting obstructive events in patients with obstructive sleep apnea. The objective of this study was to systematically review the literature for studies describing the natural history of TECSA. PubMed, Medline, Scopus, Web of Science, and Cochran Library databases were searched through June 29, 2017. Five studies were identified that discussed the natural history of TECSA. TECSA developed in 3.5%-19.8% of PAP-treated patients. Treatment-persistent central sleep apnea (TPCSA), representing protracted periods of PAP therapy-related central apneas, was noted in 14.3%-46.2% of patients with TECSA. Delayed-TECSA (D-TECSA) represents an anomalous TECSA entity appearing weeks to months after initial PAP therapy. D-TECSA was observed in 0.7%-4.2% of OSA patients undergoing PAP treatment (after at least 1 month). In patients with TECSA, a higher apnea-hypopnea index (AHI) and central apnea index at their baseline study or a higher residual AHI at their titration study may be associated with an increased likelihood of conversion to TPCSA. Overall, TECSA developed in 3.5%-19.8% of PAP-treated patients with OSA. The vast majority will experience complete resolution of central apneas over a few weeks to months. Unfortunately, about a third of patients with TECSA may continue to exhibit persistence of central sleep apnea on reevaluation. A small proportion may experience D-TECSA after few weeks to several months of initial exposure to PAP therapy.

  9. Amyloid burden and sleep blood pressure in amnestic mild cognitive impairment

    Science.gov (United States)

    Tarumi, Takashi; Harris, Thomas S.; Hill, Candace; German, Zohre; Riley, Jonathan; Turner, Marcel; Womack, Kyle B.; Kerwin, Diana R.; Monson, Nancy L.; Stowe, Ann M.; Mathews, Dana; Cullum, C. Munro

    2015-01-01

    Objective: To determine whether cortical β-amyloid (Aβ) deposition is associated with circadian blood pressure (BP) profiles and dynamic cerebral blood flow (CBF) regulation in patients with amnestic mild cognitive impairment (aMCI). Methods: Forty participants with aMCI were included in this study. Cortical Aβ depositions were measured by 18F-florbetapir PET and expressed as the standardized uptake value ratio (SUVR) relative to the cerebellum. Circadian BP profiles were measured by 24-hour ambulatory monitoring during awake and sleep periods. The dipping status of sleep BP (i.e., the percent changes from the awake BP) was calculated and dichotomized into the dipper (≥10%) and nondipper (<10%) groups. Dynamic CBF regulation was assessed by a transfer function analysis between beat-to-beat changes in BP and CBF velocity measured from the middle cerebral artery during a repeated sit-stand maneuver. Results: Age was positively correlated with a greater Aβ deposition in the posterior cingulate, precuneus, and mean cortex. Accounting for the age effect, attenuated reductions in sleep systolic BP were associated with higher levels of posterior cingulate SUVR. Consistently, the nondippers exhibited a higher SUVR in the posterior cingulate than the dippers. Transfer function gain between changes in BP and CBF velocity was diminished in the nondippers, and moreover those individuals with a lower gain exhibited a higher SUVR in the posterior cingulate. Conclusions: Attenuated reductions in sleep BP are associated with a greater Aβ burden in the posterior cingulate and altered dynamic CBF regulation in patients with aMCI. PMID:26537049

  10. High pressure effect for high-Tc superconductors

    International Nuclear Information System (INIS)

    Takahashi, Hiroki; Tomita, Takahiro

    2011-01-01

    A number of experimental and theoretical studies have been performed to understand the mechanism of high-T c superconductivity and to enhance T c . High-pressure techniques have played a very important role for these studies. In this paper, the high-pressure techniques and physical properties of high-T c superconductor under high pressure are presented. (author)

  11. Sleep habits of students attending elementary schools, and junior and senior high schools in Akita prefecture.

    Science.gov (United States)

    Takemura, Takaubu; Funaki, Kensaku; Kanbayashi, Takashi; Kawamoto, Kentaro; Tsutsui, Kou; Saito, Yasushi; Aizawa, Rika; Inomata, Shoko; Shimizu, Tetsuo

    2002-06-01

    It is widely accepted that students in Japan sleep fewer hours than what they actually need. However, epidemiological data on sleep habits among students are scarce. The sleep habits and related problems among 1650 students in Akita prefecture were studied. The results revealed that schoolchildren attending elementary schools seemed to sleep for a sufficient number of hours, whereas students attending junior or senior high schools were not sleeping enough. In particular, approximately half of the students attending senior high schools answered that they slept 6 h or less on weekdays and nodded off during classes more than twice a week.

  12. Pressure pressure-balanced pH sensing system for high temperature and high pressure water

    International Nuclear Information System (INIS)

    Tachibana, Koji

    1995-01-01

    As for the pH measurement system for high temperature, high pressure water, there have been the circumstances that first the reference electrodes for monitoring corrosion potential were developed, and subsequently, it was developed for the purpose of maintaining the soundness of metallic materials in high temperature, high pressure water in nuclear power generation. In the process of developing the reference electrodes for high temperature water, it was clarified that the occurrence of stress corrosion cracking in BWRs is closely related to the corrosion potential determined by dissolved oxygen concentration. As the types of pH electrodes, there are metal-hydrogen electrodes, glass electrodes, ZrO 2 diaphragm electrodes and TiO 2 semiconductor electrodes. The principle of pH measurement using ZrO 2 diaphragms is explained. The pH measuring system is composed of YSZ element, pressure-balanced type external reference electrode, pressure balancer and compressed air vessel. The stability and pH response of YSZ elements are reported. (K.I.)

  13. Oral pressure therapy for treatment of obstructive sleep apnea: clinical feasibility

    Directory of Open Access Journals (Sweden)

    Farid-Moayer M

    2013-05-01

    Full Text Available Mehran Farid-Moayer,1 Lawrence C Siegel,2,3 Jed Black41Peninsula Sleep Center, Burlingame, CA, USA; 2Department of Anesthesia, Stanford University School of Medicine, Stanford, CA, USA; 3Department of Clinical Affairs, ApniCure, Inc, Redwood City, CA, USA; 4Stanford Center for Sleep Research and Medicine, Stanford University School of Medicine, Stanford, CA, USAPurpose: This feasibility study examined the initial-use safety and effectiveness of a new noninvasive oral pressure therapy (OPT system developed to treat obstructive sleep apnea (OSA.Methods: The OPT system consists of a console that connects with flexible tubing to a premanufactured polymer mouthpiece. Through the mouthpiece, a pump in the console creates oral vacuum intended to move the soft palate anteriorly to decrease obstruction of the airway during sleep. The mouthpiece was produced in ten different sizes to accommodate a range of oral dimensions. Subjects with OSA in this single-center, single-night study underwent a polysomnography (PSG study at baseline, followed by PSG during use of OPT.Results: Fifty-six men and 20 women, aged 50.8 ± 12.0 years (mean ± standard deviation [SD], had OSA with apnea–hypopnea indices (AHI greater than five events per hour at baseline. Body weight averaged 98.0 ± 18.2 kg (mean ± SD, body mass index ranged from 22.6 kg/m2 to 57.9 kg/m2 and averaged 32.5 ± 5.8 kg/m2 (mean ± SD. OPT was generally well tolerated without any serious adverse events. Baseline AHI was 38.7 ± 27.5 events/hour (mean ± SD and was reduced with treatment to 24.6 ± 25.7 events/hour (P < 0.001, Cohen's d 0.53. Treatment produced AHI less than or equal to ten events/hour in 38% of the subjects. Oxygen desaturation index was 30.1 ± 23.7 events/hour at baseline versus 15.8 ± 19.1 events/hour with treatment (P < 0.001, Cohen's d 0.66. The minimum oxygen saturation increased with treatment from 77.9 ± 8.3 to 82.2 ± 7.9 (P < 0.001, Cohen's d 0.53. Stage-N1 sleep shifts

  14. Nocturnal Blood Pressure Variability in Patients with Obstructive Sleep Apnea Syndrome.

    Science.gov (United States)

    Martynowicz, H; Porębska, I; Poręba, R; Mazur, G; Brzecka, A

    2016-01-01

    Obstructive sleep apnea (OSA) is a common respiratory disorder associated with hypertension and cardiovascular complications. Blood pressure variability may be a sign of risk of cardiovascular events. The aim of this study was to investigate the hypothesis that severe OSA syndrome is associated with increased blood pressure variability. Based on respiratory polygraphy, 58 patients were categorized into two groups: severe OSA with apnea/hypopnea index (AHI) greater than 29 episodes per hour (mean 52.2 ± 19.0/h) and mild-to-moderate OSA with AHI between 5 and 30 episodes per hour (mean 20.2 ± 7.8/h). A 24-h noninvasive blood pressure monitoring was performed. The standard deviation of mean blood pressure was used as the indicator of blood pressure variability. In patients with severe, compared with mild-to-moderate OSA, a higher mean nocturnal systolic blood pressure (133.2 ± 17.4 mmHg vs. 117.7 ± 31.2 mmHg, p variability (12.1 ± 6.0 vs. 7.6 ± 4.3, p variability (10.5 ± 6.1 vs. 7.3 ± 4.0 p variability (9.1 ± 4.9 mmHg vs. 6.8 ± 3.5 mmHg) were detected. The findings of the study point to increased nocturnal systolic and diastolic arterial blood pressure and blood pressure variability as risk factors of cardiovascular complications in patients with severe OSA.

  15. High pressure gas reinjection unit

    Energy Technology Data Exchange (ETDEWEB)

    1976-03-01

    Nuovo Pignone has built for gas reinjection at Ekofisk the highest pressure injection unit to date: suction pressure 246 bar, discharge 647 bar, for 5.7 million cu m/day of natural gas, and driven by a GE MS 5001 gas turbine of 24,000 hp. The barrel-type compressor has been used already in Algeria at Hassi Messaoud. Full scale tests have shown that the unit is satisfactory; special attention being paid to the stability of the rotor. Air cooled heat exchangers were used in the test loop to cool the discharge gas; at Ekofisk, heat exchangers with sea water will be used. The valves in the test loop were of a special, low- noise type. Vibrations of the rotor system and changes in gas pressure monitored, showing that a pressure of 680 bars can be achieved without instability. Economic considerations lead to preference for rotary compressors driven by gas turbines for similar applications in the exploitation of oil fields. A graph of the characteristics of the unit is given.

  16. High-pressure boron hydride phases

    International Nuclear Information System (INIS)

    Barbee, T.W. III; McMahan, A.K.; Klepeis, J.E.; van Schilfgaarde, M.

    1997-01-01

    The stability of boron-hydrogen compounds (boranes) under pressure is studied from a theoretical point of view using total-energy methods. We find that the molecular forms of boranes known to be stable at ambient pressure become unstable at high pressure, while structures with extended networks of bonds or metallic bonding are energetically favored at high pressures. If such structures are metastable on return to ambient pressure, they would be energetic as well as dense hydrogen storage media. An AlH 3 -like structure of BH 3 is particularly interesting in that it may be accessible by high-pressure diamond anvil experiments, and should exhibit both second-order structural and metal-insulator transitions at lower pressures. copyright 1997 The American Physical Society

  17. Stress and sleep quality in high school brazilian adolescents

    Directory of Open Access Journals (Sweden)

    Gema Mesquita

    2010-06-01

    Full Text Available OBJECTIVE: The objective of the present study is to analyze the effect of stress on sleep quality in a group of adolescents. METHOD: Two high schools in Alfenas, southern Minas Gerais State, Brazil, were chosen to participate in the study. The sample consisted of both genders (n=160 with 65.63% females. The age range of participants was 15 to18 years. The Pittsburgh Sleep Quality Index (PSQI was applied for collection of data to quantify sleep quality. The Lipp Inventory of Stress Symptoms that objectively identifies symptoms of stress was applied. RESULTS: It was observed that 23.53% of stressed students and 45.33% of unstressed ones sleep well; 76.47% of stressed pupils and 54.67% of those unstressed do not sleep well. With regard to school performance, a mean of 0.65 was found for stressed students and 0.60 for those without stress, Mann-Whitney (p=0.0596. CONCLUSION: Stress contributed to raising the percentage of poor sleepers, as ell as increasing ean school performance.OBJETIVO: O objetivo do presente estudo foi analisar a influência do stress sobre a qualidade do sono em um grupo de adolescentes. MÉTODO: Foram escolhidas duas instituições educacionais do ensino médio, na cidade de Alfenas, sul de Minas Gerais, Brasil. A amostra foi composta por ambos os sexos (n=160, com 65,63% do sexo feminino. A faixa etária dos participantes foi de 15 a 18 anos. Para a coleta de dados aplicou-se: Índice de Qualidade de Sono de Pittsburgh (IQSP utilizado para quantificar a qualidade do sono; o Inventário de Sintomas de Stress para Adultos de Lipp (ISSL que identifica de modo objetivo a sintomatologia de stress foi aplicado. RESULTADOS: Observou-se que 23,53% dos estressados dormem bem e 45,33% dos não estressados dormem bem; 76,47% dos estressados não dormem bem e 54,67% dos não estressados não dormem bem. Quanto ao rendimento escolar têm-se as médias 0,65 para os alunos estressados e 0,60 para aqueles que não sofrem de stress, Mann

  18. Effects of High Altitude on Sleep and Respiratory System and Theirs Adaptations

    Directory of Open Access Journals (Sweden)

    Turhan San

    2013-01-01

    Full Text Available High-altitude (HA environments have adverse effects on the normal functioning body of people accustomed to living at low altitudes because of the change in barometric pressure which causes decrease in the amount of oxygen leading to hypobaric hypoxia. Sustained exposure to hypoxia has adverse effects on body weight, muscle structure and exercise capacity, mental functioning, and sleep quality. The most important step of acclimatization is the hyperventilation which is achieved by hypoxic ventilatory response of the peripheral chemoreceptors. Hyperventilation results in increase in arterial carbondioxide concentration. Altitude also affects sleep and cardiac output, which is the other determinant of oxygen delivery. Upon initial exposure to HA, the resting pulse rate increases rapidly, but with acclimatization, heart rate and cardiac output tend to fall. Another important component that leads to decrease in cardiac output is the reduction in the stroke volume with acclimatization. During sleep at HA, the levels of CO2 in the blood can drop very low and this can switch off the drive to breathe. Only after the body senses a further drop in O2 levels breathing is started again. Periodic breathing is thought to result from instability in the control system through the hypoxic drive or the response to CO2.

  19. High-pressure torsion of hafnium

    International Nuclear Information System (INIS)

    Edalati, Kaveh; Horita, Zenji; Mine, Yoji

    2010-01-01

    Pure Hf (99.99%) is processed by high-pressure torsion (HPT) under pressures of 4 and 30 GPa to form an ultrafine-grained structure with a gain size of ∼180 nm. X-ray diffraction analysis shows that, unlike Ti and Zr, no ω phase formation is detected after HPT processing even under a pressure of 30 GPa. A hydride formation is detected after straining at the pressure of 4 GPa. The hydride phase decomposes either by application of a higher pressure as 30 GPa or by unloading for prolong time after HPT processing. Microhardness, tensile and bending tests show that a high hardness (360 Hv) and an appreciable ductility (8%) as well as high tensile and bending strength (1.15 and 2.75 GPa, respectively) are achieved following the high-pressure torsion.

  20. High cardiac vagal control is related to better subjective and objective sleep quality.

    Science.gov (United States)

    Werner, Gabriela G; Ford, Brett Q; Mauss, Iris B; Schabus, Manuel; Blechert, Jens; Wilhelm, Frank H

    2015-03-01

    Cardiac vagal control (CVC) has been linked to both physical and mental health. One critical aspect of health, that has not received much attention, is sleep. We hypothesized that adults with higher CVC--operationalized by high-frequency heart rate variability (HF-HRV)--will exhibit better sleep quality assessed both subjectively (i.e., with Pittsburgh Sleep Quality Index) and objectively (i.e., with polysomnography). HF-HRV was measured in 29 healthy young women during an extended neutral film clip. Participants then underwent full polysomnography to obtain objective measures of sleep quality and HF-HRV during a night of sleep. As expected, higher resting HF-HRV was associated with higher subjective and objective sleep quality (i.e., shorter sleep latency and fewer arousals). HF-HRV during sleep (overall or separated by sleep phases) showed less consistent relationships with sleep quality. These findings indicate that high waking CVC may be a key predictor of healthy sleep. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Impact of Polysomnographic Parameters on Continuous Positive Airway Pressure in Patient with Obstructive Sleep Apnea in 2012

    Directory of Open Access Journals (Sweden)

    Abolfazl Mozafari

    2014-06-01

    Full Text Available Background & objectives : O bstructive sleep apnea is a preventable and prevalent major health hazard with serious health consequences including excessive daytime sleepiness, cognitive disturbances, depression, cardiovascular diseases and hypertension. Obstructive sleep apnea is a disorder affecting 2 to 4% of the adult population. The continuous positive airway pressur e (CPAP i s the most efficacious therapy and is often the first option for these patients. The pressure titration during laboratory polysomnography is required for treatment by CPAP.   Methods: The patients with obstructive sleep apnea requiring continuous positive airway pressure treatment were selected . CPAP titration was done according to American Academy of Sleep Medicine protocol. Comparison among continuous positive airway pressure with polysomnographic parameters was performed and analyzed with Pearson correlation coefficient. For analysis of qualitative parameters, we used chi-square and then checked with SPSS version 18 software.   Results: From 125 patients with obstructive sleep apnea, there were 112 cases with inclusion criteria. Mean age of participants was 55.07 ± 12, male frequency was 59.2%, apnea hypopnea index was 43.62 and mean continuous positive airway pressure was 12.50 . There was significant relationship among the pressure of continuous positive airway pressure with apnea hypopnea index (P=0.028, arousal index (P=0.011, body mass index (P=0.041 and O2 desaturation index (P=0.022, although age was not significantly related.   Conclusion: In accordance to this data, we found out a prediction equation for optimal CPAP in our patients

  2. Continuous Positive Airway Pressure Adherence In Patients with Obstructive Sleep Apnea & Symptomatic BPH.

    Science.gov (United States)

    Metta, Ramesh V V S; Zaka, Awais; Lee, Vincent C; Mador, M Jeffery

    2017-04-01

    Purpose To determine the short-term and long-term adherence rates with continuous positive airway pressure (CPAP) therapy in sleep apnea patients with benign prostatic hyperplasia (BPH) compared to matched controls. Methods A case-control retrospective analysis was performed in a veterans affairs hospital. All symptomatic patients with BPH (n = 107) ever started on CPAP therapy between 2006 and 2012 were compared with controls matched for severity of sleep apnea (AHI). Adherence measures were obtained at the third and twelfth month visits. The cases included symptomatic BPH patients on active medical therapy. Diuretic use among cases and controls, and severity of nocturia among the cases were also analyzed. Results The mean AHI among cases and controls was 35.6 ± 27.3 and 35.5 ± 31 (p = 0.96). The population was male and predominantly Caucasian. There was no statistically significant difference in percent days CPAP device use ≥4 h. between symptomatic BPH patients and controls at 3-month (51.6 ± 38 vs. 47.2 ± 36; p = 0.43) and 1-year (64 ± 40.5 vs. 64.7 ± 31.3; p = 0.90) visits. The use of diuretics in the cases and controls, and the severity of nocturia in the cases did not influence adherence with CPAP therapy. Conclusions BPH or diuretic use did not affect adherence with CPAP therapy in obstructive sleep apnea. Severity of nocturia did not have any influence on adherence among the cases. BPH, regardless of the severity of nocturia, and diuretic use does not influence CPAP adherence in patients with OSA.

  3. High pressure X-ray studies

    International Nuclear Information System (INIS)

    Sikka, S.K.

    1981-01-01

    High pressure research has already led to new insights in the physical properties of materials and at times to the synthesis of new ones. In all this, X-ray diffraction has been a valuable diagnostic experimental tool. In particular, X-rays in high pressure field have been used (a) for crystallographic identification of high pressure polymorphs and (b) for study of the effect of pressure on lattice parameters and volume under isothermal conditions. The results in the area (a) are reviewed. The techniques of applying high pressures are described. These include both static and dynamic shockwave X-ray apparatus. To illustrate the effect of pressure, some of the pressure induced phase transitions in pure metals are described. It has been found that there is a clear trend for elements in any group of the periodic table to adopt similar structures at high pressures. These studies have enabled to construct generalized phase diagrams for many groups. In the case of alloys, the high pressure work done on Ti-V alloys is presented. (author)

  4. Prevalence of central sleep apnea during continous positive airway pressure (CPAP) titration in subjects with obstructive sleep apnea syndrome at an altitude of 2640 m.

    Science.gov (United States)

    Bazurto Zapata, Maria Angelica; Martinez-Guzman, William; Vargas-Ramirez, Leslie; Herrera, Karen; Gonzalez-Garcia, Mauricio

    2015-03-01

    The occurrence of central apneas when applying positive pressure (CPAP) to patients with obstructive sleep apnea syndrome (OSAS) is called complex sleep apnea (CompSA). This causes poor adherence to CPAP and persistence of symptoms. In Bogota, a city located at an altitude of 2640 m above sea level, chronic hypoxemia can generate certain instability of the respiratory system during sleep which could increase the presence of central apnea. The aim was to establish the prevalence of central apnea (central apnea index >5/h) in adults with moderate or severe OSAS during CPAP titration, and the factors associated with this. Patients over 18 years old with OSAS were referred to the Fundacion Neumologica Colombiana Sleep Center, from January 2008 to June 2010. Polysomnogram (PSG) for CPAP titration was performed according to the American Academy of Sleep Medicine criteria. The prevalence was calculated and the clinical and baseline PSG factors associated with the CompSA were analyzed. We included 988 patients, 58% men. CompSA prevalence was 11.6%. Factors associated with CompSA were: central apneas in the baseline PSG (OR: 5.34 [3.49-8.16]), history of heart failure (OR: 2.53 [1.58-4.07]), and male sex (OR: 1.68 [1.06-2.69]). The prevalence of complex sleep apnea in Bogota (11.6%) was intermediate compared to the reported in lower altitudes. The factors associated with the development of CompSA were male sex, heart failure, and the presence of central apnea in the baseline PSG. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Managing Stress to Control High Blood Pressure

    Science.gov (United States)

    ... Aortic Aneurysm More Managing Stress to Control High Blood Pressure Updated:Jan 29,2018 The importance of stress ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  6. Application of High Pressure in Food Processing

    Directory of Open Access Journals (Sweden)

    Herceg, Z.

    2011-01-01

    Full Text Available In high pressure processing, foods are subjected to pressures generally in the range of 100 – 800 (1200 MPa. The processing temperature during pressure treatments can be adjusted from below 0 °C to above 100 °C, with exposure times ranging from a few seconds to 20 minutes and even longer, depending on process conditions. The effects of high pressure are system volume reduction and acceleration of reactions that lead to volume reduction. The main areas of interest regarding high-pressure processing of food include: inactivation of microorganisms, modification of biopolymers, quality retention (especially in terms of flavour and colour, and changes in product functionality. Food components responsible for the nutritive value and sensory properties of food remain unaffected by high pressure. Based on the theoretical background of high-pressure processing and taking into account its advantages and limitations, this paper aims to show its possible application in food processing. The paper gives an outline of the special equipment used in highpressure processing. Typical high pressure equipment in which pressure can be generated either by direct or indirect compression are presented together with three major types of high pressure food processing: the conventional (batch system, semicontinuous and continuous systems. In addition to looking at this technology’s ability to inactivate microorganisms at room temperature, which makes it the ultimate alternative to thermal treatments, this paper also explores its application in dairy, meat, fruit and vegetable processing. Here presented are the effects of high-pressure treatment in milk and dairy processing on the inactivation of microorganisms and the modification of milk protein, which has a major impact on rennet coagulation and curd formation properties of treated milk. The possible application of this treatment in controlling cheese manufacture, ripening and safety is discussed. The opportunities

  7. Asthma outcomes improve with continuous positive airway pressure for obstructive sleep apnea.

    Science.gov (United States)

    Serrano-Pariente, J; Plaza, V; Soriano, J B; Mayos, M; López-Viña, A; Picado, C; Vigil, L

    2017-05-01

    Continuous positive airway pressure (CPAP) in asthma patients with concomitant obstructive sleep apnea syndrome (OSAS) seems to have a favorable impact on asthma, but data are inconsistent due to methodological limitations of previous studies. Prospective, multicenter study. We examined asthma outcomes after 6 months of CPAP in 99 adult asthma patients (mean age 57 years) with OSAS (respiratory disturbance index ≥20). Asthma control and quality of life were assessed with the Asthma Control Questionnaire (ACQ) and the Mini Asthma Quality of Life Questionnaire (MiniAQLQ), respectively. Data were analyzed by intention-to-treat basis. The mean ± SD score of the ACQ decreased from 1.39 ± 0.91 at baseline to 1.0 ± 0.78 at 6 months (P = 0.003), the percentage of patients with uncontrolled asthma from 41.4% to 17.2% (P = 0.006), and the percentage of patients with asthma attacks in the 6 months before and after treatment from 35.4% to 17.2% (P = 0.015). The score of the mAQLQ increased from 5.12 ± 1.38 to 5.63 ± 1.17 (P = 0.009). There were also significant improvements in symptoms of gastroesophageal reflux and rhinitis, bronchial reversibility, and exhaled nitric oxide values (all P obstructive sleep apnea syndrome. © 2016 The Authors. Allergy published by John Wiley & Sons Ltd.

  8. High pressure injection of dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Glensvig, M.; Sorenson, S.C.; Abata, D.L.

    1997-08-01

    The purpose of this investigation was to achieve a better understanding of the fundamental spray behavior of DME (Dimenthyl Ether) using a standard diesel pump with pintle and hole nozzles. Fundamental spray behavior was characterized by determining fuel spray penetration and angle, atomization and evaporation. The influences of opening pressure, nozzle geometry and ambient pressure above and below the critical pressure of the fuel on the spray behavior were investigated. The influence of opening pressures on the spray characteristics for the hole nozzle was investigated. The results showed that for opening pressures of 120 bar and 180 bar the spray has a similar appearance. For the higher opening pressure (200 bar and 240 bar), the initial spray breaks up very rapidly giving a high initial spray angle. The opening pressure had little influence on spray penetration. The spray angle later in the injection increased as the opening pressure was decreased. Above the critical pressure, the spray from the hole nozzle had a more irregular shape. Penetration decreased and the spray angle increased above the critical pressure. Three pintle nozzles with different geometries and opening pressures were tested. The appearance of the three sprays were very similar. The sprays seemed to be more sharply pointed as the nozzle hole angle decreased. The nozzle with the 4 deg. hole nozzle angle and an opening pressure of 280 bar had the highest penetration and highest initial spray angle. The pintle nozzle with the 12 deg. hole nozzle angle and opening pressure of approx. 450 bar was tested above the critical ambient pressure. Penetration was very similar for injection above and below the critical ambient pressure, while the spray angle decreased for the spray above the critical ambient pressure. (au)

  9. High Pressure EVA Glove (HPEG), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Final Frontier Design's (FFD) High Pressure EVA Glove (HPEG) is a game changing technology enabling future exploration class space missions. The high operating...

  10. Consistently high sports/exercise activity is associated with better sleep quality, continuity and depth in midlife women: the SWAN sleep study.

    Science.gov (United States)

    Kline, Christopher E; Irish, Leah A; Krafty, Robert T; Sternfeld, Barbara; Kravitz, Howard M; Buysse, Daniel J; Bromberger, Joyce T; Dugan, Sheila A; Hall, Martica H

    2013-09-01

    To examine relationships between different physical activity (PA) domains and sleep, and the influence of consistent PA on sleep, in midlife women. Cross-sectional. Community-based. 339 women in the Study of Women's Health Across the Nation Sleep Study (52.1 ± 2.1 y). None. Sleep was examined using questionnaires, diaries and in-home polysomnography (PSG). PA was assessed in three domains (Active Living, Household/Caregiving, Sports/Exercise) using the Kaiser Physical Activity Survey (KPAS) up to 4 times over 6 years preceding the sleep assessments. The association between recent PA and sleep was evaluated using KPAS scores immediately preceding the sleep assessments. The association between the historical PA pattern and sleep was examined by categorizing PA in each KPAS domain according to its pattern over the 6 years preceding sleep assessments (consistently low, inconsistent/consistently moderate, or consistently high). Greater recent Sports/Exercise activity was associated with better sleep quality (diary "restedness" [P sleep continuity (diary sleep efficiency [SE; P = 0.02]) and depth (higher NREM delta electroencephalographic [EEG] power [P = 0.04], lower NREM beta EEG power [P Sports/Exercise activity was also associated with better Pittsburgh Sleep Quality Index scores (P = 0.02) and higher PSG-assessed SE (P sleep and Active Living or Household/Caregiving activity (either recent or historical pattern) were noted. Consistently high levels of recreational physical activity, but not lifestyle- or household-related activity, are associated with better sleep in midlife women. Increasing recreational physical activity early in midlife may protect against sleep disturbance in this population.

  11. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan

    2013-01-01

    Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

  12. Improvement in headaches with continuous positive airway pressure for obstructive sleep apnea: a retrospective analysis.

    Science.gov (United States)

    Johnson, Karin G; Ziemba, Alexis M; Garb, Jane L

    2013-02-01

    We aimed to identify clinical features in patients with severe headaches that predicted obstructive sleep apnea (OSA) and determine clinical and sleep study characteristics that predicted headache improvement with continuous positive airway pressure (CPAP). Many patients with headaches complain of sleep symptoms and have OSA. There is often improvement of headaches with CPAP treatment. We conducted a retrospective chart review of all patients referred to adult neurology clinic for headaches and sent for polysomnography between January 2008 and December 2009. Follow-up ranged from 18 to 42 months. Eighty-two headache patients (70 females, 12 males) were studied. Mean age was 45±13 years (females 45±13, males 43±11) and mean body mass index was 32±9. Headache types included 17% chronic migraine without aura, 22% episodic migraine without aura, 32% migraine with aura, 21% tension-type headache, 6% chronic post-traumatic headache, 11% medication overuse headache, and 7% other types. All patients were receiving standard treatment for their headaches by their neurologist. Fifty-two patients (63%) had OSA. Increasing age, female gender, and chronic migraine without aura were predictive of OSA. Of the patients with OSA, 33 (63%) used CPAP and 27 (82%) were adherent to CPAP. Headache improvement was reported by 40 patients (49%) due to either standard medical therapy or CPAP. Patients with OSA who were CPAP adherent (21/27) were more likely to have improvement in headaches than patients intolerant of CPAP (2/6), those that did not try CPAP (8/19), and those who did not have OSA (16/30) (P=.045). Of the 33 patients who used CPAP, 13 reported improvement in headaches specifically due to CPAP therapy and 10 additional patients noted benefit in sleep symptoms. The presence of witnessed apneas (P=.045) and male gender (P=.021) predicted improvement in headaches due to CPAP. Headache patients should be evaluated for the presence of OSA. Treating OSA improves headaches in some

  13. Short Sleep Duration Among Middle School and High School Students - United States, 2015.

    Science.gov (United States)

    Wheaton, Anne G; Jones, Sherry Everett; Cooper, Adina C; Croft, Janet B

    2018-01-26

    Insufficient sleep among children and adolescents is associated with increased risk for obesity, diabetes, injuries, poor mental health, attention and behavior problems, and poor academic performance (1-4). The American Academy of Sleep Medicine has recommended that, for optimal health, children aged 6-12 years should regularly sleep 9-12 hours per 24 hours and teens aged 13-18 years should sleep 8-10 hours per 24 hours (1). CDC analyzed data from the 2015 national, state, and large urban school district Youth Risk Behavior Surveys (YRBSs) to determine the prevalence of short sleep duration (school nights among middle school and high school students in the United States. In nine states that conducted the middle school YRBS and included a question about sleep duration in their questionnaire, the prevalence of short sleep duration among middle school students was 57.8%, with state-level estimates ranging from 50.2% (New Mexico) to 64.7% (Kentucky). The prevalence of short sleep duration among high school students in the national YRBS was 72.7%. State-level estimates of short sleep duration for the 30 states that conducted the high school YRBS and included a question about sleep duration in their questionnaire ranged from 61.8% (South Dakota) to 82.5% (West Virginia). The large percentage of middle school and high school students who do not get enough sleep on school nights suggests a need for promoting sleep health in schools and at home and delaying school start times to permit students adequate time for sleep.

  14. Titration effectiveness of two autoadjustable continuous positive airway pressure devices driven by different algorithms in patients with obstructive sleep apnoea.

    Science.gov (United States)

    Damiani, Mario Francesco; Quaranta, Vitaliano Nicola; Tedeschi, Ersilia; Drigo, Riccardo; Ranieri, Teresa; Carratù, Pierluigi; Resta, Onofrio

    2013-08-01

    Nocturnal application of continuous positive airway pressure (CPAP) is the standard treatment for patients with obstructive sleep apnoea (OSA). Determination of the therapeutic pressure (CPAP titration) is usually performed by a technician in the sleep laboratory during attended polysomnography. One possible alternative to manual titration is automated titration. Indeed, during the last 15 years, devices have been developed that deliver autoadjustable CPAP (A-CPAP). The aim of the present study was to compare the titration effectiveness of two A-CPAP devices using different flow-based algorithms in patients with OSA. This is a randomized study; 79 subjects underwent two consecutive unattended home A-CPAP titration nights with two different devices (Autoset Resmed; Remstar Auto Respironics); during the third and the fourth night, patients underwent portable monitoring in the sleep laboratory during fixed CPAP at the A-CPAP recommended pressure. Bland Altman plots showed good agreement between the recommended median and maximal pressure levels obtained with the two devices. A significant improvement was observed in all the sleep parameters by both A-CPAP machines to a similar degree. It was observed that the two A-CPAP devices using different algorithms are equally effective in initial titration of CPAP. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

  15. Simulated driving in obstructive sleep apnoea-hypopnoea : effects of oral appliances and continuous positive airway pressure

    NARCIS (Netherlands)

    Hoekema, Aarnoud; Stegenga, Boudewijn; Bakker, Marije; Brouwer, Wiebo H.; de Bont, Lambert G. M.; Wijkstra, Peter J.; van der Hoeven, Johannes H.

    Impaired simulated driving performance has been demonstrated in obstructive sleep apnoea-hypopnoea syndrome (OSAHS) patients. Although continuous positive airway pressure (CPAP) generally improves simulated driving performance, the effects of oral-appliance (OA) therapy are unknown. The aims of this

  16. Impact of heated humidification with automatic positive airway pressure in obstructive sleep apnea therapy.

    Science.gov (United States)

    Salgado, Sara Moreira da Silva Trindade; Boléo-Tomé, José Pedro Correia Fernandes; Canhão, Cristina Maria Sardinha; Dias, Ana Rita Tavares; Teixeira, Joana Isaac; Pinto, Paula Maria Gonçalves; Caetano, Maria Cristina de Brito Eusébio Bárbara Prista

    2008-09-01

    To study the impact that heated humidification instituted in the beginning of automatic positive airway pressure (APAP) therapy has on compliance with and the side effects of the treatment. Thirty-nine treatment-naïve patients with obstructive sleep apnea were randomized into two groups to receive APAP using one of two modalities: with heated humidification (APAPwith group); and without heated humidification (APAPw/o group).Patients were evaluated at 7 and 30 days after APAP initiation. The following parameters were analyzed: compliance with treatment (mean number of hours/night); side effects (dry nose or mouth, nasal obstruction and rhinorrhea); daytime sleepiness (Epworth sleepiness scale score) and subjective comfort (visual analog scale score). Patients were also evaluated in terms of residual apnea-hypopnea index (AHI), as well as mean pressures and leaks registered in the ventilators. There were no differences between the two groups in terms of mean age (APAPwith: 57.4 +/- 9.2; APAPw/o: 56.5 +/- 10.7 years), AHI (APAPwith: 28.1 +/- 14.0; APAPw/o: 28.8 +/- 20.5 events/hour of sleep), baseline Epworth score (APAPwith: 11.2 +/- 5.8; APAPw/o: 11.9 +/- 6.3) and initial nasal symptoms. Compliance was similar in both groups (APAPwith: 5.3 +/- 2.4; APAPw/o: 5.2 +/- 2.3 h/night). There were no differences in any of the other parameters analyzed. The introduction of heated humidification at the beginning of APAP therapy provided no advantage in terms of treatment compliance or side effects of treatment.

  17. Exercise lowers blood pressure in university professors during subsequent teaching and sleeping hours

    Directory of Open Access Journals (Sweden)

    Ribeiro F

    2011-10-01

    Full Text Available Fabiana Ribeiro1, Carmen S Grubert Campbell1, Gisele Mendes1, Gisela Arsa1,3, Sérgio R Moreira2, Francisco M da Silva1, Jonato Prestes1, Rafael da Costa Sotero1, Herbert Gustavo Simões1 1Graduate Program on Physical Education and Health, Catholic University of Brasilia, Brasilia; 2Federal University of Vale do São Francisco, Petrolina, 3Graduate Program on Physical Education, Nine of July University, São Paulo SP, Brazil Background: University professors are subjected to psychological stress that contributes to blood pressure (BP reactivity and development of hypertension. The purpose of this study was to investigate the effects of exercise on BP in university professors during teaching and sleeping hours. Methods: Twelve normotensive professors (42.2 ± 10.8 years, 74.2 ± 11.2 kg, 172.8 ± 10.4 cm, 20.1% ± 6.7% body fat randomly underwent control (CONT and exercise (EX30 sessions before initiating their daily activities. EX30 consisted of 30 minutes of cycling at 80%–85% of heart rate reserve. Ambulatory BP was monitored for 24 hours following both sessions. Results: BP increased in comparison with pre-session resting values during teaching after CONT (P < 0.05 but not after EX30. Systolic, diastolic, and mean arterial BP showed a more pronounced nocturnal dip following EX30 (approximately -14.7, -12.7, and -9.6 mmHg, respectively when compared with CONT (approximately -6, -5 and -3 mmHg. Conclusion: Exercise induced a BP reduction in university professors, with the main effects being observed during subsequent teaching and sleeping hours. Keywords: post-exercise blood pressure, aerobic exercise, activities of daily living

  18. High-pressure mechanical instability in rocks.

    Science.gov (United States)

    Byerlee, J D; Brace, W F

    1969-05-09

    At a confining pressure of a few kilobars, deformation of many sedimentary rocks, altered mafic rocks, porous volcanic rocks, and sand is ductile, in that instabilities leading to audible elastic shocks are absent. At pressures of 7 to 10 kilobars, however, unstable faulting and stick-slip in certain of these rocks was observed. This high pressure-low temperature instability might be responsible for earthquakes in deeply buried sedimentary or volcanic sequences.

  19. Sleep Patterns in Adults with a Diagnosis of High-Functioning Autism Spectrum Disorder.

    Science.gov (United States)

    Baker, Emma K; Richdale, Amanda L

    2015-11-01

    To examine sleep patterns and sleep problems and their relationship with daytime functioning in adults with a diagnosis of an autism spectrum disorder and no comorbid intellectual disability (high-functioning autism spectrum disorder [HFASD]) compared to neurotypical (NT) adults. Cross-sectional. Home-based study. 36 adults with HFASD and 36 age-, intelligence quotient- and sex-matched NT adults. Participants completed an online questionnaire battery including the Pittsburgh Sleep Quality Index (PSQI), a 14-d sleep wake diary and 14-d actigraphy data collection. Adults with HFASD had significantly more general sleep disturbances and higher scores on the PSQI, longer sleep onset latencies (actigraphy), and poorer sleep efficiency (diary) and these results remained significant after accounting for the False Discovery Rate. Those adults with HFASD who did not have a comorbid diagnosis of anxiety/depression had significantly shorter total sleep time (diary and actigraphy) compared to NT adults. Compared to NT adults, the HFASD group self-reported significantly poorer refreshment scores upon waking in the morning and higher scores on the daytime dysfunction due to sleepiness subscale of the PSQI. These findings support the notion that problems related to sleep, in particular insomnia, continue into adulthood in individuals with high-functioning autism spectrum disorder. © 2015 Associated Professional Sleep Societies, LLC.

  20. Influences of obstructive sleep apnea on blood pressure variability might not be limited only nocturnally in middle-aged hypertensive males.

    Science.gov (United States)

    Shao, Liang; Heizhati, Mulalibieke; Yao, Xiaoguang; Wang, Yingchun; Abulikemu, Suofeiya; Zhang, Delian; Zhou, Ling; Hong, Jing; Li, Nanfang

    2018-05-01

    In this cross-sectional study, we analyzed the potential association between sleep measures and blood pressure variability. Ninety-three middle-aged hypertensive males, who underwent polysomnography and 24-h ambulatory blood pressure monitoring, were enrolled. Blood pressure variability was assessed by blood pressure standard deviation. Obstructive sleep apnea (apnea hypopnea index ≥ 15) was diagnosed in 52 (55.91%) patients. Mean body mass index and age were 27.77 ± 3.11 kg/m 2 and 44.05 ± 8.07 years, respectively. Hypertensive males with obstructive sleep apnea showed significantly higher 24-h, diurnal, and nocturnal diastolic blood pressure variability, compared to those without obstructive sleep apnea. While total cohort was further divided into two groups using the median of oxygen desaturation index, another indicator for severity of OSA, significant differences were also observed in 24-h, diurnal, and nocturnal diastolic blood pressure variability between two groups with higher and lower oxygen desaturation index. While subjects were also divided into two groups via the mean of sleep stage 1, hypertensive males with sleep stage 1 ≥ 8.1% showed significantly higher diurnal diastolic blood pressure variability than those with sleep stage 1 blood pressure variability; oxygen desaturation index of 3% with 24-h diastolic, diurnal, and nocturnal diastolic blood pressure; and sleep stage 1 was with 24-h and with diurnal diastolic blood pressure variability in all study subjects. Effects of obstructive sleep apnea on blood pressure variability may not be limited nocturnally.

  1. Gender, Headaches, and Sleep Health in High School Students.

    Science.gov (United States)

    Ming, Xue; Radhakrishnan, Varsha; Kang, Lilia; Pecor, Keith

    2016-09-01

    The effects of gender, headaches, and their interaction on sleep health (sleep duration, sleep onset and continuity, and indications of hypersomnolence) have not been well studied. For American adolescents, we contrasted sleep health variables between males (n = 378) and females (n = 372) and between individuals with chronic headaches (n = 102 females and 60 males) and without chronic headaches (n = 270 females and 318 males) using data from surveys. Not all measures of sleep health differed between groups, but the following patterns were observed for the measures that did differ. Females reported shorter sleep durations on school nights (p = 0.001), increased likelihood of sleepiness on school days (p sleep durations on weekends (p = 0.009) and higher hypersomnolence scores (p = 0.009) than individuals without headaches. Interestingly, females with headaches reported worse sleep health than females without headaches for multiple measures. Males with headaches did not differ from males without headaches, except for greater waking at night (p = 0.04). These results are consistent with other studies of gender-based differences in sleep health and emphasize the importance of recognizing the risk of headache in female adolescents and treating that condition to prevent additional sleep health issues.

  2. Nucleation at high pressure I: Theoretical considerations.

    NARCIS (Netherlands)

    Luijten, C.C.M.; Dongen, van M.E.H.

    1999-01-01

    A theoretical approach is presented that accounts for the influence of high pressure background gases on the vapor-to-liquid nucleation process. The key idea is to treat the carrier gas pressure as a perturbation parameter that modifies the properties of the nucleating substance. Two important

  3. High-pressure differential scanning microcalorimeter.

    Science.gov (United States)

    Senin, A A; Dzhavadov, L N; Potekhin, S A

    2016-03-01

    A differential scanning microcalorimeter for studying thermotropic conformational transitions of biopolymers at high pressure has been designed. The calorimeter allows taking measurements of partial heat capacity of biopolymer solutions vs. temperature at pressures up to 3000 atm. The principles of operation of the device, methods of its calibration, as well as possible applications are discussed.

  4. High-pressure oxidation of ethane

    DEFF Research Database (Denmark)

    Hashemi, Hamid; G. Jacobsen, Jon; Rasmussen, Christian T.

    2017-01-01

    Ethane oxidation at intermediate temperatures and high pressures has been investigated in both a laminar flow reactor and a rapid compression machine (RCM). The flow-reactor measurements at 600–900 K and 20–100 bar showed an onset temperature for oxidation of ethane between 700 and 825 K, depending...... on pressure, stoichiometry, and residence time. Measured ignition delay times in the RCM at pressures of 10–80 bar and temperatures of 900–1025 K decreased with increasing pressure and/or temperature. A detailed chemical kinetic model was developed with particular attention to the peroxide chemistry. Rate...

  5. High-pressure phase transitions of strontianite

    Science.gov (United States)

    Speziale, S.; Biedermann, N.; Reichmann, H. J.; Koch-Mueller, M.; Heide, G.

    2015-12-01

    Strontianite (SrCO3) is isostructural to aragonite, a major high-pressure polymorph of calcite. Thus it is a material of interest to investigate the high-pressure phase behavior of aragonite-group minerals. SrCO3 is a common component of natural carbonates and knowing its physical properties at high pressures is necessary to properly model the thermodynamic properties of complex carbonates, which are major crustal minerals but are also present in the deep Earth [Brenker et al., 2007] and control carbon cycling in the Earth's mantle. The few available high-pressure studies of SrCO3 disagree regarding both pressure stability and structure of the post-aragonite phase [Lin & Liu, 1997; Ono et al., 2005; Wang et al. 2015]. To clarify such controversies we investigated the high-pressure behavior of synthetic SrCO3 by Raman spectroscopy. Using a diamond anvil cell we compressed single-crystals or powder of strontianite (synthesized at 4 GPa and 1273 K for 24h in a multi anvil apparatus), and measured Raman scattering up to 78 GPa. SrCO3 presents a complex high-pressure behavior. We observe mode softening above 20 GPa and a phase transition at 25 - 26.9 GPa, which we interpret due to the CO3 groups rotation, in agreement with Lin & Liu [1997]. The lattice modes in the high-pressure phase show dramatic changes which may indicate a change from 9-fold coordinated Sr to a 12-fold-coordination [Ono, 2007]. Our results confirm that the high-pressure phase of strontianite is compatible with Pmmn symmetry. References Brenker, F.E. et al. (2007) Earth and Planet. Sci. Lett., 260, 1; Lin, C.-C. & Liu, L.-G. (1997) J. Phys. Chem. Solids, 58, 977; Ono, S. et al. (2005) Phys. Chem. Minerals, 32, 8; Ono, S. (2007) Phys. Chem. Minerals, 34, 215; Wang, M. et al. (2015) Phys Chem Minerals 42, 517.

  6. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  7. High pressure processing of meat

    DEFF Research Database (Denmark)

    Grossi, Alberto; Christensen, Mette; Ertbjerg, Per

    the rheological properties of pork meat batters by inducing formation of protein gels. HP induced protein gels are suggested to be formed by high molecular weight myofibrillar protein aggregates and by peptides formed by lysosomal enzyme-induced cleavage of myofibrillar proteins. Perspectives: The data presented...

  8. Blood pressure response to CPAP treatment in subjects with obstructive sleep apnoea: the predictive value of 24-h ambulatory blood pressure monitoring.

    Science.gov (United States)

    Castro-Grattoni, Anabel L; Torres, Gerard; Martínez-Alonso, Montserrat; Barbé, Ferran; Turino, Cecilia; Sánchez-de-la-Torre, Alicia; Cortijo, Anunciacion; Duran-Cantolla, Joaquin; Egea, Carlos; Cao, Gonzalo; Sánchez-de-la-Torre, Manuel

    2017-10-01

    The reduction in blood pressure (BP) with continuous positive airway pressure (CPAP) is modest and highly variable. In this study, we identified the variables that predict BP response to CPAP.24-h ambulatory BP monitoring (ABPM), C-reactive protein (CRP), leptin, adiponectin and 24-h urinary catecholamine were measured before and after 6 months of CPAP in obstructive sleep apnoea (OSA) patients.Overall, 88 middle-aged, obese male patients with severe OSA (median apnoea-hypopnoea index 42 events·h -1 ) were included; 28.4% had hypertension. 62 patients finished the study, and 60 were analysed. The daytime diastolic BP (-2 mmHg) and norepinephrine (-109.5 nmol·day -1 ) were reduced after CPAP, but no changes in the 24-h BP, night-time BP, dopamine, epinephrine, CRP, leptin or adiponectin were detected. The nocturnal normotension was associated with an increased night-time-BP (+4 mmHg) after CPAP, whereas nocturnal hypertension was associated with a reduction of 24-h BP (-3 mmHg). A multivariate linear regression model showed differential night-time BP changes after CPAP. Specifically, low night-time heart rate (CPAP and support the usefulness of 24-h ABPM for OSA patients before treatment initiation. These results need to be confirmed in further studies. Copyright ©ERS 2017.

  9. Raman spectroscopy of triolein under high pressures

    Science.gov (United States)

    Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

    2010-03-01

    This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

  10. Continuous Positive Airway Pressure Prevents Hypoxia in Dental Patient with Obstructive Sleep Apnea Syndrome under Intravenous Sedation.

    Science.gov (United States)

    Kasatkin, Anton A; Reshetnikov, Aleksei P; Urakov, Aleksandr L; Baimurzin, Dmitrii Y

    2017-01-01

    Use of sedation in patients with obstructive sleep apnea (OSA) in dentistry is limited. Hypoxia may develop during medication sleep in dental patients with OSA because of repetitive partial or complete obstruction of the upper airway. In this regard, anesthesiologists prefer not to give any sedative to surgical patients with OSA or support the use of general anesthesia due to good airway control. We report a case where we could successfully sedate a dental patient with OSA using intraoperative continuous positive airway pressure (CPAP) without hypoxia. Use of sedation and intraoperative CPAP in patients with OSA may be considered only if the effectiveness at home CPAP therapy is proven.

  11. Why sleep matters: differences in daytime functioning between adolescents with low and high chronic sleep reduction and short and long sleep durations

    NARCIS (Netherlands)

    Dewald-Kaufmann, J.F.; Oort, F.J.; Bögels, S.M.; Meijer, A.M.

    2013-01-01

    Sleep problems are prevalent in adolescents and can severely impair their daytime functioning. This study aims to investigate differences in daytime functioning (e.g., depressive symptoms, attention problems, school functioning, and school performance) between adolescents with high and low chronic

  12. High pressure semiconductor physics I

    CERN Document Server

    Willardson, R K; Paul, William; Suski, Tadeusz

    1998-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise indeed that this tra...

  13. Symptoms of insomnia among patients with obstructive sleep apnea before and after two years of positive airway pressure treatment.

    Science.gov (United States)

    Björnsdóttir, Erla; Janson, Christer; Sigurdsson, Jón F; Gehrman, Philip; Perlis, Michael; Juliusson, Sigurdur; Arnardottir, Erna S; Kuna, Samuel T; Pack, Allan I; Gislason, Thorarinn; Benediktsdóttir, Bryndis

    2013-12-01

    To assess the changes of insomnia symptoms among patients with obstructive sleep apnea (OSA) from starting treatment with positive airway pressure (PAP) to a 2-y follow-up. Longitudinal cohort study. Landspitali--The National University Hospital of Iceland. There were 705 adults with OSA who were assessed prior to and 2 y after starting PAP treatment. PAP treatment for OSA. All patients underwent a medical examination along with a type 3 sleep study and answered questionnaires on health and sleep before and 2 y after starting PAP treatment. The change in prevalence of insomnia symptoms by subtype was assessed by questionnaire and compared between individuals who were using or not using PAP at follow-up. Symptoms of middle insomnia were most common at baseline and improved significantly among patients using PAP (from 59.4% to 30.7%, P insomnia tended to persist regardless of PAP treatment, and symptoms of late insomnia were more likely to improve among patients not using PAP. Patients with symptoms of initial and late insomnia at baseline were less likely to adhere to PAP (odds ratio [OR] 0.56, P = 0.007, and OR 0.53, P insomnia. Symptoms of initial and late insomnia, however, tended to persist regardless of positive airway pressure treatment and had a negative effect on adherence. Targeted treatment for insomnia may be beneficial for patients with obstructive sleep apnea comorbid with insomnia and has the potential to positively affect adherence to positive airway pressure.

  14. Modeling High Pressure Micro Hollow Cathode Discharges

    National Research Council Canada - National Science Library

    Boeuf, Jean-Pierre; Pitchford, Leanne

    2004-01-01

    This report results from a contract tasking CPAT as follows: The Grantee will perform theoretical modeling of point, surface, and volume high-pressure plasmas created using Micro Hollow Cathode Discharge sources...

  15. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    Foam glass is a high added value product which contributes to waste recycling and energy efficiency through heat insulation. The foaming can be initiated by a chemical or physical process. Chemical foaming with aid of a foaming agent is the dominant industrial process. Physical foaming has two...... to expand. After heat-treatment foam glass can be obtained with porosities of 80–90 %. In this study we conduct physical foaming of cathode ray tube (CRT) panel glass by sintering under high pressure (5-25 MPa) using helium, nitrogen, or argon at 640 °C (~108 Pa s). Reheating a sample in a heating...... variations. One way is by saturation of glass melts with gas. The other involves sintering of powdered glass under a high gas pressure resulting in glass pellets with high pressure bubbles entrapped. Reheating the glass pellets above the glass transition temperature under ambient pressure allows the bubbles...

  16. Preeclampsia and High Blood Pressure During Pregnancy

    Science.gov (United States)

    ... Gynecologists f AQ FREQUENTLY ASKED QUESTIONS FAQ034 PREGNANCY Preeclampsia and High Blood Pressure During Pregnancy • What is ... is chronic hypertension during pregnancy managed? • What is preeclampsia? • When does preeclampsia occur? • What causes preeclampsia? • What ...

  17. Teaming Up Against High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    This podcast is based on the September 2012 CDC Vital Signs report. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.

  18. Relationship between chronic intermittent hypoxia and intraoperative mean arterial pressure in obstructive sleep apnea patients having laparoscopic bariatric surgery.

    Science.gov (United States)

    Turan, Alparslan; You, Jing; Egan, Cameron; Fu, Alex; Gazmuri, Ignazia; Khanna, Ashish; Eshraghi, Yashar; Ghosh, Raktim; Bose, Somnath; Qavi, Shahbaz; Arora, Lovkesh; Sessler, Daniel I; Doufas, Anthony G

    2015-01-01

    Recurrent nocturnal hypoxemia in obstructive sleep apnea enhances sympathetic function, decreases baroreceptor sensitivity, and weakens peripheral vascular responses to adrenergic signals. The authors hypothesized that the percentage of total sleep time spent at oxyhemoglobin saturation (SaO2) less than 90% and minimum nocturnal SaO2 on preoperative polysomnography are associated with decreased intraoperative mean arterial pressure. The authors examined the records of all patients who had laparoscopic bariatric surgery at Cleveland Clinic between 2005 and 2009 and an available polysomnography study. The authors assessed the relationships between the percentage of total sleep time spent at SaO2 less than 90% and minimum nocturnal SaO2, and the time-weighted average of mean arterial pressure. The authors used multivariable regression models to adjust for prespecified clinical confounders. Two hundred eighty-one patients were included in the analysis. The average change in the time-weighted average of mean arterial pressure was -0.02 (97.5% CI, -0.08, 0.04) mmHg for each 1% absolute increase in the percentage of sleep time spent at SaO2 less than 90% (P = 0.50). The average change was -0.13 (97.5% CI, -0.27, 0.01) mmHg, for each 1% absolute decrease in the minimum SaO2 (P = 0.04 > significance criterion of 0.025, Bonferroni correction). An unplanned analysis estimated 1% absolute decrease in minimum SaO2 was associated with -0.22 (98.75% CI, -0.39, -0.04) mmHg, change in mean arterial pressure (P = 0.002) in the time period between endotracheal intubation and trocar insertion. Recurrent nocturnal hypoxemia in obstructive sleep apnea is not a risk marker for intraoperative hypotension.

  19. High-pressure portable pneumatic drive unit.

    Science.gov (United States)

    Hete, B F; Savage, M; Batur, C; Smith, W A; Golding, L A; Nosé, Y

    1989-12-01

    The left ventricular assist device (LVAD) of the Cleveland Clinic Foundation (CCF) is a single-chamber assist pump, driven by a high-pressure pneumatic cylinder. A low-cost, portable driver that will allow cardiac care patients, with a high-pressure pneumatic ventricle assist, more freedom of movement has been developed. The compact and light-weight configuration can provide periods of 2 h of freedom from a fixed position driver and does not use exotic technology.

  20. High Pressure Physics at Brigham Young University

    Science.gov (United States)

    Decker, Daniel

    2000-09-01

    I will discuss the high pressure research of Drs. J. Dean Barnett, Daniel L. Decker and Howard B. Vanfleet of the department of Physics and Astronomy at Brigham Young University and their many graduate students. I will begin by giving a brief history of the beginning of high pressure research at Brigham Young University when H. Tracy Hall came to the University from General Elecrtric Labs. and then follow the work as it progressed from high pressure x-ray diffraction experiments, melting curve measurements under pressure to pressure effects on tracer diffusion and Mossbauer effect spectra. This will be followed by showing the development of pressure calibration techniques from the Decker equation of state of NaCl to the ruby fluorescence spectroscopy and a short discussion of using a liquid cell for hydrostatic measurements and temperature control for precision high pressure measurements. Then I will conclude with a description of thermoelectric measuremnts, critical phenomena at the magnetic Curie point, and the tricritical point of BaTiO_3.

  1. An examination of sleep health, lifestyle and mental health in junior high school students.

    Science.gov (United States)

    Tanaka, Hideki; Taira, Kazuhiko; Arakawa, Masashi; Masuda, Atushi; Yamamoto, Yukari; Komoda, Yoko; Kadegaru, Hathuko; Shirakawa, Shuichiro

    2002-06-01

    The factors that influence sleep health and mental health in junior high school students' lifestyles was examined. The proportion of students who replied that they feel bad in the morning, and who do not have breakfast was significantly higher in poor sleepers. The proportion of students who regularly take exercise was significantly lower among poor sleepers. Compared with good sleepers, poor sleepers had a higher number of illnesses and their General Health Questionnaire score was worse. The study's results suggest that sleep health is closely related to both physical and mental health, and that habits such as exercise, and regular sleeping and eating, are important for maintaining and improving students' sleep health.

  2. [Compliance with continuous positive airway pressure therapy in patients with sleep apnea/hypopnea syndrome].

    Science.gov (United States)

    Gallego, Claudio W; Dibur, Eduardo; Salomone, César; Di Bartolo, Carlos G

    2004-01-01

    Predictive factors and compliance level were evaluated in a group of patients with sleep apnea syndrome under CPAP treatment, assessing side effects and equipment condition: silicone interface (SI), mask-conectors (M-C), air tube (AT) and head strap (HS). Patients with >3mo treatment were included, clock counter reading was registered at the beginning, 2 and 4 mo. Patients were considered compliant (C+) when usage was >4h/day and >5day/week. Of 46 patients (male 34; age 62 +/- 9years; BMI 33 +/- 7kg/m2; AHI 38 +/- 18/h; time of therapy 2.1 +/- 1.7years; CPAP 9 +/- 1.4 cmH2O), 34 had a clock counter and 24 (71%) were C+. Initial symptoms included: somnolence (65%), snoring (39%), bed-partner witnessed apneas (28%). Comparing C+ and C- we didn't find significant difference in age, BMI, CPAP pressure, length of therapy, AHI and pre-treatment Epworth classification. Referred vs. measured time of use in C+ and C- were 6.6 +/- 1 vs. 6.1 +/- 1 h/d (p=0.02) and 5.6 +/- 1 vs. 2.4 +/- 1 h/d (pcongestion 27%, sleep disruption 11%, CPAP noisy 9%, dry nose, rhinorrhea and skin irritation 7%. Twenty seven percent of patients reduced the CPAP use because of the SE. Correction strategies included: humidifier, nasal steroid, surgery or infiltration of turbinates. Comparing the condition of SI, M-C, AT and HS between 1year of use, we observed a lower percentage of fine elements (87 to 44%, 74 to 44%, 83 to 44%, 91 to 78%, respectively). Most common defects included stiffness of SI, cracks in SI, M-C and AT, loose conexions. The study confirms the importance of objective monitoring in patients with CPAP. Side effects and equipment condition require special attention because this could affect an effective treatment.

  3. Barometric pressure change and heart rate response during sleeping at 3000 m altitude

    Science.gov (United States)

    Horiuchi, Masahiro; Endo, Junko; Handa, Yoko; Nose, Hiroshi

    2018-05-01

    We investigated effects of change in barometric pressure ( P B) with climate change on heart rate (HR) during sleep at 3000 m altitude. Nineteen healthy adults (15 males and four females; mean age 32 years) participated in this study. We measured P B (barometry) and HR (electrocardiography) every minute during their overnight stay in a mountain lodge at 3000 m. We also measured resting arterial oxygen saturation (SpO2) and evaluated symptoms of acute mountain sickness (AMS) by using the Lake Louise Questionnaire at 2305 and 3000 m, respectively. P B gradually decreased during the night at the speed of approximately - 0.5 hPa/h. We found that HR during sleep decreased linearly as P B decreased in all subjects, with significance ( r = 0.492-0.893; all, P < 0.001). Moreover, cross correlation analysis revealed that HR started to decrease after 15 min following the decrease in P B, on average. SpO2 was 93.8 ± 1.7% at 2305 m before climbing, then decreased significantly to 90.2 ± 2.2% at the lodge before going to bed, and further decreased to 87.5 ± 2.7% after waking (all, P < 0.05). Four of the 19 subjects showed a symptom of AMS after waking (21%). Further, the decrease in HR in response to a given decrease in P B (ΔHR/ΔPB) was negatively related with a decrease in SpO2 from before going to bed to after waking at 3000 m ( r = - 0.579, P = 0.009) and with total AMS scores after waking ( r = 0.489, P = 0.033).

  4. Holographic interferometry of high pressure

    International Nuclear Information System (INIS)

    McIlwain, M.E.

    1987-01-01

    Measurements in turbulent flows have been historically performed using various types of probes and optical diagnostic methods. In general, probes suffer from plasma perturbation effects and are single point determination methods. Optical methods appear to be better suited to determinations in turbulent flows, however interpretation of the resulting data can often be complex. Methods such as laser Doppler anemometry, which relies on entrained particles, suffers from the fact that particles small enough to be swept along by the plasma are usually melted or sublimed in the plasma. Light refraction or diffraction methods such as shadow photography, interferometry, and holography have also been used to observe plasma flows. These methods typically suffer from the difficulty of interpreting line of sight images and obtaining quantitative data. A new method based on multi-pass holographic interferometry will be discussed. This method has certain advantages which can significantly simplify the complexity of line of sight interferometry image deconvolution. When the method employs high speed cinematography, time resolved images of the plasma flow can be obtained. This method has been applied to both transferred and non-transferred arcs and various types of DC-plasma torch produced jets. These studies and conclusions as to the usefulness of the technique are presented

  5. High-pressure oxidation of methane

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Gersen, Sander

    2016-01-01

    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly...... diluted in nitrogen. It was found that under the investigated conditions, the onset temperature for methane oxidation ranged from 723 K under reducing conditions to 750 K under stoichiometric and oxidizing conditions. The RCM experiments were carried out at pressures of 15–80 bar and temperatures of 800......–1250 K under stoichiometric and fuel-lean (Φ=0.5) conditions. Ignition delays, in the range of 1–100 ms, decreased monotonically with increasing pressure and temperature. A chemical kinetic model for high-pressure methane oxidation was established, with particular emphasis on the peroxide chemistry...

  6. On high-pressure melting of tantalum

    Science.gov (United States)

    Luo, Sheng-Nian; Swift, Damian C.

    2007-01-01

    The issues related to high-pressure melting of Ta are discussed within the context of diamond-anvil cell (DAC) and shock wave experiments, theoretical calculations and common melting models. The discrepancies between the extrapolations of the DAC melting curve and the melting point inferred from shock wave experiments, cannot be reconciled either by superheating or solid-solid phase transition. The failure to reproduce low-pressure DAC melting curve by melting models such as dislocation-mediated melting and the Lindemann law, and molecular dynamics and quantum mechanics-based calculations, undermines their predictions at moderate and high pressures. Despite claims to the contrary, the melting curve of Ta (as well as Mo and W) remains inconclusive at high pressures.

  7. Adolescents' sleep in low-stress and high-stress (exam) times: a prospective quasi-experiment.

    Science.gov (United States)

    Dewald, Julia F; Meijer, Anne Marie; Oort, Frans J; Kerkhof, Gerard A; Bögels, Susan M

    2014-01-01

    This prospective quasi-experiment (N = 175; mean age = 15.14 years) investigates changes in adolescents' sleep from low-stress (regular school week) to high-stress times (exam week), and examines the (moderating) role of chronic sleep reduction, baseline stress, and gender. Sleep was monitored over three consecutive weeks using actigraphy. Adolescents' sleep was more fragmented during the high-stress time than during the low-stress time, meaning that individuals slept more restless during stressful times. However, sleep efficiency, total sleep time, and sleep onset latency remained stable throughout the three consecutive weeks. High chronic sleep reduction was related to later bedtimes, later sleep start times, later sleep end times, later getting up times, and more time spent in bed. Furthermore, low chronic sleep reduction and high baseline stress levels were related to more fragmented sleep during stressful times. This study shows that stressful times can have negative effects on adolescents' sleep fragmentation, especially for adolescents with low chronic sleep reduction or high baseline stress levels.

  8. Pressure sensor for high-temperature liquids

    International Nuclear Information System (INIS)

    Forster, G.A.

    1978-01-01

    A pressure sensor for use in measuring pressures in liquid at high temperatures, especially such as liquid sodium or liquid potassium, comprises a soft diaphragm in contact with the liquid. The soft diaphragm is coupled mechanically to a stiff diaphragm. Pressure is measured by measuring the displacement of both diaphragms, typically by measuring the capacitance between the stiff diaphragm and a fixed plate when the stiff diaphragm is deflected in response to the measured pressure through mechanical coupling from the soft diaphragm. Absolute calibration is achieved by admitting gas under pressure to the region between diaphragms and to the region between the stiff diaphragm and the fixed plate, breaking the coupling between the soft and stiff diaphragms. The apparatus can be calibrated rapidly and absolutely

  9. Self-Reported Napping Behavior Change After Continuous Positive Airway Pressure Treatment in Older Adults with Obstructive Sleep Apnea.

    Science.gov (United States)

    Hsieh, Cheng-Fang; Riha, Renata L; Morrison, Ian; Hsu, Chung-Yao

    2016-08-01

    To assess the effect of continuous positive airway pressure (CPAP) on napping behavior in adults aged 60 and older with obstructive sleep apnea-hypopnea syndrome (OSAHS). Retrospective cohort study using questionnaires. Sleep center. Individuals starting CPAP treatment between April 2010 and March 2012 (mean age 65.2 ± 4.7; M:F = 3.9:1; N = 107). All subjects underwent sleep studies, clinical reviews, and CPAP adherence checks and completed a questionnaire regarding CPAP adherence, current employment status, sleep patterns before and after CPAP, and factors affecting their current sleep patterns. CPAP treatment duration was 82.7 ± 30.0 weeks, and objective adherence was 5.4 ± 2.0 hours per night overall. Daytime nap frequency before CPAP treatment was higher in those with a history of stroke or cardiovascular disease. Both sexes had a significant reduction in daytime napping (men, P napping (men, P nap duration (men, P nap duration was associated with younger age (odds ratio (OR) = 0.86, P = .04), a decrease in ESS score (OR = 1.20, P = .03), and longer self-reported daily nap duration at baseline (OR = 31.52, P nap frequency and daily nap duration. Aging or shorter baseline daily nap duration may attenuate this effect. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  10. Solids, liquids, and gases under high pressure

    Science.gov (United States)

    Mao, Ho-Kwang; Chen, Xiao-Jia; Ding, Yang; Li, Bing; Wang, Lin

    2018-01-01

    Pressure has long been recognized as a fundamental thermodynamic variable but its application was previously limited by the available pressure vessels and probes. The development of megabar diamond anvil cells and a battery of associated in-laboratory and synchrotron techniques at the turn of the century have opened a vast new window of opportunities. With the addition of the pressure dimension, we are facing a new world with an order of magnitude more materials to be discovered than all that have been explored at ambient pressure. Pressure drastically and categorically alters all elastic, electronic, magnetic, structural, and chemical properties, and pushes materials across conventional barriers between insulators and superconductors, amorphous and crystalline solids, ionic and covalent compounds, vigorously reactive and inert chemicals, etc. In the process, it reveals surprising high-pressure physics and chemistry and creates novel materials. This review describes the principles and methodology used to reach ultrahigh static pressure: the in situ probes, the physical phenomena to be investigated, the long-pursued goals, the surprising discoveries, and the vast potential opportunities. Exciting examples include the quest for metallic hydrogen, the record-breaking superconducting temperature of 203 K in HnS , the complication of "free-electron gas" alkali metals, the magnetic collapse in 3 d transition elements, the pressure-induced superconductivity from topological insulators, the novel stoichiometry in simple compounds, the interaction of nanoscience, the accomplishment of 750 GPa pressure, etc. These highlights are the integral results of technological achievements, specific measurements, and theoretical advancement; therefore, the same highlights will appear in different sections corresponding to these different aspects. Overall, this review demonstrates that high-pressure research is a new dimension in condensed-matter physics.

  11. Radioresistance increase in polymers at high pressures

    International Nuclear Information System (INIS)

    Milinchuk, V.; Kirjukhin, V.; Klinshpont, E.

    1977-01-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibres were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures. (J.B.)

  12. Work schedule influence on sleep habits in elementary and high school teachers according to chronotype

    Directory of Open Access Journals (Sweden)

    Jane Carla de Souza

    2014-09-01

    Full Text Available The influence of work schedule on sleep habits and quality, and daytime sleepiness according to individual preferences in sleep schedules was assessed in 131 elementary and high school teachers through questionnaires. Teachers who initiate classes around 7:00 hr wake up earlier and show more frequency of poor sleep quality than those who start classes in the afternoon. Between them, those who have a preference for intermediate or later hours for sleep are more irregular in their wake up schedules and increase their sleep duration on the weekend compared to those with earlier sleep preferences. On the other hand, working only in the afternoon seems to provide better sleep/awake conditions for teachers, because they keep the same sleep duration during the week and on the weekend, and they are diagnosed with less daytime sleepiness. Therefore, the discussion of school start times, originally proposed for adolescents, needs to be magnified to teachers, contributing to improvement of sleep habits and life quality in school environments.

  13. Association of Sleep Duration with Obesity among US High School Students

    Directory of Open Access Journals (Sweden)

    Richard Lowry

    2012-01-01

    Full Text Available Increasing attention is being focused on sleep duration as a potential modifiable risk factor associated with obesity in children and adolescents. We analyzed data from the national Youth Risk Behavior Survey to describe the association of obesity (self-report BMI ≥95th percentile with self-reported sleep duration on an average school night, among a representative sample of US high school students. Using logistic regression to control for demographic and behavioral confounders, among female students, compared to 7 hours of sleep, both shortened (≤4 hours of sleep; adjusted odds ratio (95% confidence interval, AOR = 1.50 (1.05–2.15 and prolonged (≥9 hours of sleep; AOR = 1.54 (1.13–2.10 sleep durations were associated with increased likelihood of obesity. Among male students, there was no significant association between obesity and sleep duration. Better understanding of factors underlying the association between sleep duration and obesity is needed before recommending alteration of sleep time as a means of addressing the obesity epidemic among adolescents.

  14. Sleep patterns in high school and university students: a longitudinal study.

    Science.gov (United States)

    Urner, Martin; Tornic, Jure; Bloch, Konrad E

    2009-08-01

    We performed a longitudinal study to investigate whether changes in social zeitgebers and age alter sleep patterns in students during the transition from high school to university. Actimetry was performed on 24 high-school students (mean age+/-SD: 18.4+/-0.9 yrs; 12 females) for two weeks. Recordings were repeated in the same subjects 5 yrs later when they were university students. The sleep period duration and its center, the mid-sleep time, and total sleep time were estimated by actimetry. Actigraphic total sleep time was similar when in high school and at the university on school days (6.31+/-0.47 vs. 6.45+/-0.80 h, p = ns) and longer on leisure days by 1.10+/-1.10 h (p school days) when in high school, but not at the university. Compared to the high school situation, the mid-sleep time was delayed when at the university on school days (03:11+/-0.6 vs. 03:55+/-0.7 h, p sleep times on school and leisure days when in high school were significantly correlated with the corresponding values 5 yrs later when at the university (r = 0.58 and r = 0.55, p sleep time between school and leisure days when students attended high school and the delayed mid-sleep time on school days when students attended university are consistent with a circadian phase shift due to changes in class schedules, other zeitgebers, and lifestyle preferences. Age-related changes may also have occurred, although some individuality of the sleep pattern was maintained during the 5 yr study span. These findings have important implications for optimizing school and work schedules in students of different age and level of education.

  15. observed by high pressure NMR and NQR

    Indian Academy of Sciences (India)

    Akogun, Hyogo 678-1297, Japan. ∗. Email: kohara@sci.himeji tech.ac.jp. Abstract. NMR and NQR studies on two interesting systems (URu2Si2, CeTIn5) were performed under high pressure. (1) URu2Si2: In the pressure range 3.0 to 8.3 kbar, we have observed new 29Si. NMR signals arising from the antiferromagnetic ...

  16. Survey on a sleep habits for university and high school students.

    OpenAIRE

    林, 光緒; 堀, 忠雄

    1988-01-01

    A survey was performed on 466 high school students and 403 university students. 86% of high school students and 89% of university students estimated their customary sleep time to be 6-8 hours. Although there was no significant difference between high school students and university students with awake time, bed time was later for university students than high school students. So that sleep time was shorter for university students. Also there was more regular sleepers for high school students a...

  17. High pressure, high current, low inductance, high reliability sealed terminals

    Science.gov (United States)

    Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN

    2010-03-23

    The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

  18. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

    2014-01-01

    Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

  19. High-Pressure Polymorphism in Orthoamphiboles

    Science.gov (United States)

    Finkelstein, G. J.; Zhang, D.; Shelton, H.; Dera, P.

    2017-12-01

    Amphiboles are double-chain silicate minerals that are the structurally hydrated counterpart to single-chain, anhydrous pyroxenes. They may play an important role in the earth as a carrier for volatiles in subduction zones, as well as a generator for seismic anisotropy in the upper mantle. Recent work has described previously unrecognized high-pressure polymorphism at low temperatures in a variety of pyroxene minerals, which may be relevant for the structure and dynamics of thick, cold, subducted slabs. However, high-pressure polymorphism in amphiboles above a few GPa in pressure has not been well explored, and if similar polymorphism to pyroxenes exists in this mineral family, it may affect the extent and depth of volatile transport in amphiboles, as well as their rheological properties. At low temperatures and high pressures, orthopyroxenes undergo crystal structure transitions at lower pressures than clinopyroxenes (10-30 GPa vs. > 50 GPa), so for this study we have investigated polymorphism in the anthophyllite-gedrite (Al-free and Al rich) orthoamphibole solid solution series. Using neon gas-loaded diamond anvil cells, we compressed both phases to a maximum pressure of 31 GPa, and observed transitions to new monoclinic structures in both endmembers. In this presentation, we will discuss the details of these transitions and implications for the earth's interior.

  20. Sleep position and the ocular surface in a high airflow environment

    Directory of Open Access Journals (Sweden)

    Vinod Gauba, FRCOphth

    2014-01-01

    Full Text Available Purpose: To study the relationship between sleep position and ocular surface symptoms and signs in an high air flow environment. Methods: Prospective observational study of new patients attending the dry eye clinic was performed. Patients with pre-existing ocular history, relevant systemic history (e.g. Sjogren’s syndrome or who were using topical or systemic therapy for dry eye were not included. Data were collected from the patient to document their dry eye symptoms; preferred dependent sleeping side and their bedroom airflow. All patients were examined by a clinician blind to the patient’s responses where Schirmer’s test and slit lamp examination were performed looking for the presence of lagophthalmos and corneal epitheliopathy. Results: 48 patients enrolled into the study of which 23 were males and 25 were females with a normal and comparable age distribution. The study found a strong association between patients’ preferred sleeping side and the incidence of corneal epitheliopathy in the contralateral eye particularly in patients with evidence of lagophthalmos. Dry eye symptoms were found to be worse and tear production lower on the contralateral side to the preferred sleeping side particularly in patients who sleep in a high airflow environment. Conclusion: In patients sleeping in a high airflow environment with nocturnal lagophthalmos, this study observed an association between preferred dependent sleep position and increased dry eye symptoms, lower Schirmer’s scores and increased corneal epitheliopathy in the contralateral eye. Keywords: Sleep, Dry eyes, Lagophthalmos, Epiphora

  1. High-pressure oxidation of methane

    NARCIS (Netherlands)

    Hashemi, Hamid; Christensen, Jakob M.; Gersen, Sander; Levinsky, Howard; Klippenstein, Stephen J.; Glarborg, Peter

    2016-01-01

    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly

  2. High pressure synthesis of bismuth disulfide

    DEFF Research Database (Denmark)

    Søndergaard-Pedersen, Simone; Nielsen, Morten Bormann; Bremholm, Martin

    In this research the BiS2 compound was synthesized by a high pressure and high temperature method using a multi-anvil large volume press and the structure was solved by single crystal diffraction. The structure contains Bi atoms in distorted square-based pyramidal coordination to five surrounding...

  3. High-purity aluminium creep under high hydrostatic pressure

    International Nuclear Information System (INIS)

    Zajtsev, V.I.; Lyafer, E.I.; Tokij, V.V.

    1977-01-01

    The effect of the hydrostatic pressure on the rate of steady-state creep of high-purity aluminium was investigated. It is shown that the hydrostatic pressure inhibits the creep. The activation volume of the creep is independent of the direction in the range of (4.7-6.2) kg/mm 2 and of the pressure in the range of (1-7.8000) atm. It is concluded that self-diffusion does not control the creep of high-purity aluminium at room temperature in the investigated stress and pressure range

  4. Association between Sleep Duration and Perceived Stress: Salaried Worker in Circumstances of High Workload

    Directory of Open Access Journals (Sweden)

    Dong-Woo Choi

    2018-04-01

    Full Text Available The aim of this study was to find the association between sleep duration and perceived stress in salaried workers according to occupational categories and which lifestyle factors affected those correlations in South Korea. This study used data from the 2015 Community Health Survey (CHS. The self-reported sleep duration was used as the dependent variable in this study. We explored sleep duration and stress awareness among salaried workers, as well as household income and educational level with multiple logistic regression analysis. Salaried workers who slept for five or less hours had a higher odds ratio for high-stress awareness (OR: 1.86, 95% CI: 1.74–1.98. Stress awareness is associated with short sleep duration; specialized workers, office workers, those with above mid-high household income and graduate, university, or college level workers especially need to sleep adequately to manage stress.

  5. Hydrogen - High pressure production and storage

    International Nuclear Information System (INIS)

    Lauretta, J.R

    2005-01-01

    The development of simple, safe and more and more efficient technologies for the production and the storage of hydrogen is necessary condition for the transition towards the economy of hydrogen.In this work the hydrogen production studies experimentally to high pressure by electrolysis of alkaline solutions without the intervention of compressing systems and its direct storage in safe containers.The made tests show that the process of electrolysis to high pressure is feasible and has better yield than to low pressure, and that is possible to solve the operation problems, with relatively simple technology.The preliminary studies and tests indicate that the system container that studied is immune to the outbreak and can have forms and very different sizes, nevertheless, to reach or to surpass the efficiency of storage of the conventional systems the investments necessary will be due to make to be able to produce aluminum alloy tubes of high resistance

  6. Continuous Positive Airway Pressure: Is it a route for infection in those with Obstructive Sleep Apnoea?

    Directory of Open Access Journals (Sweden)

    Liam Mercieca

    Full Text Available Introduction: Continuous positive airway pressure (CPAP is the standard treatment for obstructive sleep apnoea (OSA, with limited data about the prevalence of respiratory infections and microbial colonization in these patients. Objectives: The aim of this study was to determine if CPAP use is associated with respiratory infections and to identify the organisms that colonize or infect these patients. Method: A retrospective, case-controlled study in patients diagnosed with OSA was carried out. 137 patients were recruited and interviewed using a questionnaire. A nasal swab was taken from each patient. Patients using CPAP machines had swabs taken from masks and humidifiers. Results: 66 (48.2% patients received CPAP treatment with 60.6% of them having a heated humidifier. 78.8% were male, with the majority using a full face mask (63.6%. No significant difference was seen in the prevalence of rhinosinusitis, lower respiratory tract infections and hospital admissions for pneumonia between CPAP and non-CPAP treated patients. The presence of a humidifier did not influence the prevalence of infections. Commensal flora was predominantly cultured from nasal swabs from both patient groups. Coagulase Negative Staphylococci and Diphtheroids were the main organisms cultured from masks and humidifiers respectively. Conclusions: This study shows that the use of CPAP, choice of mask and humidifier have no significant impact on the prevalence of infections and micro-organisms isolated. This is very reassuring to the physician prescribing CPAP therapy and users.

  7. High-Tc superconductors under very high pressure

    International Nuclear Information System (INIS)

    Wijngaarden, R.J.; Scholtz, J.J.; Eenige, E.N. van; Griessen, R.

    1991-01-01

    High pressure has played a crucial role in the short history of high T c superconductors. Soon after the discovery of superconductivity by Bednorz and Muller in La-Ba-Cu-O, Chu et al. showed that the critical temperature T c could be significantly increased by pressure. This observation led to the discovery of YBa 2 Cu 3 O 7 by Wu et al. with a T c above 90 K. Incidentally, this high T c is probably also due to the fact that YBa 2 Cu 3 O 7 has two CuO 2 layers per unit cell instead of a single one in La-Ba-Cu-O. The authors discuss the high pressure dependence of the oxide superconductors, particularly at pressures above 10 GPa, and the nonmonotonic dependence of transition temperature on pressure

  8. Effects of Continuous Positive Airway Pressure on Cognitive and Functional Outcome of Stroke Patients with Obstructive Sleep Apnea : A Randomized Controlled Trial

    NARCIS (Netherlands)

    Aaronson, J.A.; Hofman, W.F.; van Bennekom, C.A.M.; van Bezeij, T.; van den Aardweg, J.G.; Groet, E.; Kylstra, W.A.; Schmand, B.

    2016-01-01

    STUDY OBJECTIVES: Obstructive sleep apnea (OSA) in stroke patients is associated with worse functional and cognitive status during inpatient rehabilitation. We hypothesized that a four-week period of continuous positive airway pressure (CPAP) treatment would improve cognitive and functional

  9. Continuous positive airway pressure treatment increases bronchial reactivity in obstructive sleep apnea patients.

    Science.gov (United States)

    Korczynski, Piotr; Gorska, Katarzyna; Przybylowski, Tadeusz; Bielicki, Piotr; Zielinski, Jan; Chazan, Ryszarda

    2009-01-01

    The effects of continuous positive airway pressure (CPAP) treatment on the function of the lower airways are poorly understood. One of the methods used to determine the influence of positive pressure breathing on lower airways is the bronchial hyperreactivity test. Some authors report that CPAP increases bronchial hyperreactivity, while others report decreases. To assess the influence of CPAP treatment on bronchial reactivity and the effects of bronchial hyperreactivity on compliance to CPAP treatment. The study group consisted of 101 obstructive sleep apnea syndrome patients (88 men and 13 women) with a mean age of 51 ± 11 years, mean apnea-hypopnea index of 53 ± 20 and mean body mass index of 32.6 ± 5.4. Patients were randomly assigned to a treatment group that received 3 weeks of CPAP therapy (group 1) or to a nontreatment control group (group 2). Pulmonary function tests and the methacholine bronchial provocation test were performed at baseline and 3 weeks later. There were no statistically significant differences between treated and control groups in anthropometry and polysomnography variables. At baseline, bronchial hyperreactivity was found in 6 patients from group 1 and 5 patients from group 2. A significant increase in bronchial reactivity was observed after CPAP treatment. Log PC20M decreased from 1.38 ± 0.30 at baseline to 1.26 ± 0.50 (p bronchial hyperreactivity during CPAP treatment were characterized by significantly lower FEV1, FVC and MEF50 values. CPAP produces statistically significant bronchial hyperreactivity. However, there were no clinical symptoms and it is not necessary to withdraw previous therapies. Copyright © 2009 S. Karger AG, Basel.

  10. High pressure freon decontamination of remote equipment

    International Nuclear Information System (INIS)

    Wilson, C.E.

    1987-01-01

    A series of decontamination tests using high pressure FREON 113 was conducted in the 200 Area of the Hanford site. The intent of these tests was to evaluate the effectiveness of FREON 113 in decontamination of manipulator components, tools, and equipment items contaminated with mixed fission products. The test results indicated that high pressure FREON 113 is very effective in removing fissile material from a variety of objects and can reduce both the quantity and the volume of the radioactive waste material presently being buried

  11. High pressure water jet cutting and stripping

    Science.gov (United States)

    Hoppe, David T.; Babai, Majid K.

    1991-01-01

    High pressure water cutting techniques have a wide range of applications to the American space effort. Hydroblasting techniques are commonly used during the refurbishment of the reusable solid rocket motors. The process can be controlled to strip a thermal protective ablator without incurring any damage to the painted surface underneath by using a variation of possible parameters. Hydroblasting is a technique which is easily automated. Automation removes personnel from the hostile environment of the high pressure water. Computer controlled robots can perform the same task in a fraction of the time that would be required by manual operation.

  12. High pressure water jet mining machine

    Science.gov (United States)

    Barker, Clark R.

    1981-05-05

    A high pressure water jet mining machine for the longwall mining of coal is described. The machine is generally in the shape of a plowshare and is advanced in the direction in which the coal is cut. The machine has mounted thereon a plurality of nozzle modules each containing a high pressure water jet nozzle disposed to oscillate in a particular plane. The nozzle modules are oriented to cut in vertical and horizontal planes on the leading edge of the machine and the coal so cut is cleaved off by the wedge-shaped body.

  13. High-Intensity Interval Training Attenuates Insulin Resistance Induced by Sleep Deprivation in Healthy Males.

    Science.gov (United States)

    de Souza, Jorge F T; Dáttilo, Murilo; de Mello, Marco T; Tufik, Sergio; Antunes, Hanna K M

    2017-01-01

    Introduction: Sleep deprivation can impair several physiological systems and recently, new evidence has pointed to the relationship between a lack of sleep and carbohydrate metabolism, consequently resulting in insulin resistance. To minimize this effect, High-Intensity Interval Training (HIIT) is emerging as a potential strategy. Objective: The aim of this study was to investigate the effects of HIIT on insulin resistance induced by sleep deprivation. Method: Eleven healthy male volunteers were recruited, aged 18-35 years, who declared taking 7-8 h sleep per night. All volunteers were submitted to four different conditions: a single night of regular sleep (RS condition), 24 h of total sleep deprivation ( SD condition), HIIT training followed by regular sleep (HIIT+RS condition), and HIIT training followed by 24 h of total sleep deprivation (HIIT+ SD condition). They performed six training sessions over 2 weeks and each session consisted of 8-12 × 60 s intervals at 100% of peak power output. In each experimental condition, tests for glucose, insulin, cortisol, free fatty acids, and insulin sensitivity, measured by oral glucose tolerance test (OGTT), were performed. Results: Sleep deprivation increased glycaemia and insulin levels, as well as the area under the curve. Furthermore, an increase in free fatty acids concentrations and basal metabolism was observed. There were no differences in the concentrations of cortisol. However, HIIT before 24 h of sleep deprivation attenuated the increase of glucose, insulin, and free fatty acids. Conclusion: Twenty-four hours of sleep deprivation resulted in acute insulin resistance. However, HIIT is an effective strategy to minimize the deleterious effects promoted by this condition.

  14. High-Intensity Interval Training Attenuates Insulin Resistance Induced by Sleep Deprivation in Healthy Males

    Directory of Open Access Journals (Sweden)

    Jorge F. T. de Souza

    2017-12-01

    Full Text Available Introduction: Sleep deprivation can impair several physiological systems and recently, new evidence has pointed to the relationship between a lack of sleep and carbohydrate metabolism, consequently resulting in insulin resistance. To minimize this effect, High-Intensity Interval Training (HIIT is emerging as a potential strategy.Objective: The aim of this study was to investigate the effects of HIIT on insulin resistance induced by sleep deprivation.Method: Eleven healthy male volunteers were recruited, aged 18–35 years, who declared taking 7–8 h sleep per night. All volunteers were submitted to four different conditions: a single night of regular sleep (RS condition, 24 h of total sleep deprivation (SD condition, HIIT training followed by regular sleep (HIIT+RS condition, and HIIT training followed by 24 h of total sleep deprivation (HIIT+SD condition. They performed six training sessions over 2 weeks and each session consisted of 8–12 × 60 s intervals at 100% of peak power output. In each experimental condition, tests for glucose, insulin, cortisol, free fatty acids, and insulin sensitivity, measured by oral glucose tolerance test (OGTT, were performed.Results: Sleep deprivation increased glycaemia and insulin levels, as well as the area under the curve. Furthermore, an increase in free fatty acids concentrations and basal metabolism was observed. There were no differences in the concentrations of cortisol. However, HIIT before 24 h of sleep deprivation attenuated the increase of glucose, insulin, and free fatty acids.Conclusion: Twenty-four hours of sleep deprivation resulted in acute insulin resistance. However, HIIT is an effective strategy to minimize the deleterious effects promoted by this condition.

  15. High-Intensity Interval Training Attenuates Insulin Resistance Induced by Sleep Deprivation in Healthy Males

    Science.gov (United States)

    de Souza, Jorge F. T.; Dáttilo, Murilo; de Mello, Marco T.; Tufik, Sergio; Antunes, Hanna K. M.

    2017-01-01

    Introduction: Sleep deprivation can impair several physiological systems and recently, new evidence has pointed to the relationship between a lack of sleep and carbohydrate metabolism, consequently resulting in insulin resistance. To minimize this effect, High-Intensity Interval Training (HIIT) is emerging as a potential strategy. Objective: The aim of this study was to investigate the effects of HIIT on insulin resistance induced by sleep deprivation. Method: Eleven healthy male volunteers were recruited, aged 18–35 years, who declared taking 7–8 h sleep per night. All volunteers were submitted to four different conditions: a single night of regular sleep (RS condition), 24 h of total sleep deprivation (SD condition), HIIT training followed by regular sleep (HIIT+RS condition), and HIIT training followed by 24 h of total sleep deprivation (HIIT+SD condition). They performed six training sessions over 2 weeks and each session consisted of 8–12 × 60 s intervals at 100% of peak power output. In each experimental condition, tests for glucose, insulin, cortisol, free fatty acids, and insulin sensitivity, measured by oral glucose tolerance test (OGTT), were performed. Results: Sleep deprivation increased glycaemia and insulin levels, as well as the area under the curve. Furthermore, an increase in free fatty acids concentrations and basal metabolism was observed. There were no differences in the concentrations of cortisol. However, HIIT before 24 h of sleep deprivation attenuated the increase of glucose, insulin, and free fatty acids. Conclusion: Twenty-four hours of sleep deprivation resulted in acute insulin resistance. However, HIIT is an effective strategy to minimize the deleterious effects promoted by this condition. PMID:29270126

  16. Hourly awakening vs continuous contact lens sensor measurements of 24-hour intraocular pressure: effect on sleep macrostructure and intraocular pressure rhythm.

    Science.gov (United States)

    Aptel, Florent; Tamisier, Renaud; Pépin, Jean-Louis; Mottet, Benjamin; Hubanova, Ralitsa; Romanet, Jean-Paul; Chiquet, Christophe

    2014-10-01

    All studies of 24-hour intraocular pressure (IOP) rhythm conducted to date have used repeated IOP measurements requiring nocturnal awakenings, potentially disturbing sleep macrostructure. To evaluate the effects on sleep architecture and IOP rhythm of hourly awakening vs a contact lens sensor (CLS) to continuously monitor IOP without awakening. Cross-sectional study at a referral center of chronobiology among 12 young healthy volunteers, with a mean (SD) age of 22.3 (2.3) years. Volunteers underwent two 24-hour IOP measurement sessions during a 2-month period. The eye order and session order were randomized. During one session, the IOP of the first eye was continuously monitored using a CLS, and the IOP of the fellow eye was measured hourly using a portable noncontact tonometer (session with nocturnal hourly awakening). During the other session, the IOP of the first eye was continuously monitored using a CLS, and the IOP of the fellow eye was not measured (session without nocturnal awakening). Overnight polysomnography was performed during the 2 sessions. A nonlinear least squares, dual-harmonic regression analysis was used to model the 24-hour IOP rhythm from the CLS data. Comparisons of acrophase, bathyphase, amplitude, and the midline estimating statistic of rhythm were used to evaluate the effect of hourly awakening on IOP rhythm. To evaluate the effects of hourly awakening on sleep architecture, comparisons of sleep structure were used, including total sleep period, rapid eye movement, wake after sleep onset, absolute and relative total sleep time, and non-rapid eye movement sleep (N1, N2, and N3). A 24-hour IOP rhythm was found in all individuals for the sessions with and without awakening (P  .30). Hourly awakening during noncontact tonometer IOP measurements did not seem to alter the mean variables of the 24-hour IOP pattern evaluated using CLS, including signal, maximum signal, minimum signal, acrophase, and bathyphase (P > .15). The 24-hour IOP

  17. Sleep and metabolic function.

    Science.gov (United States)

    Morselli, Lisa L; Guyon, Aurore; Spiegel, Karine

    2012-01-01

    Evidence for the role of sleep on metabolic and endocrine function has been reported more than four decades ago. In the past 30 years, the prevalence of obesity and diabetes has greatly increased in industrialized countries, and self-imposed sleep curtailment, now very common, is starting to be recognized as a contributing factor, alongside with increased caloric intake and decreased physical activity. Furthermore, obstructive sleep apnea, a chronic condition characterized by recurrent upper airway obstruction leading to intermittent hypoxemia and sleep fragmentation, has also become highly prevalent as a consequence of the epidemic of obesity and has been shown to contribute, in a vicious circle, to the metabolic disturbances observed in obese patients. In this article, we summarize the current data supporting the role of sleep in the regulation of glucose homeostasis and the hormones involved in the regulation of appetite. We also review the results of the epidemiologic and laboratory studies that investigated the impact of sleep duration and quality on the risk of developing diabetes and obesity, as well as the mechanisms underlying this increased risk. Finally, we discuss how obstructive sleep apnea affects glucose metabolism and the beneficial impact of its treatment, the continuous positive airway pressure. In conclusion, the data available in the literature highlight the importance of getting enough good sleep for metabolic health.

  18. Raman study of opal at high pressure

    Science.gov (United States)

    Farfan, G.; Wang, S.; Mao, W. L.

    2011-12-01

    More commonly known for their beauty and lore as gemstones, opals are also intriguing geological materials which may have potential for materials science applications. Opal lacks a definite crystalline structure, and is composed of an amorphous packing of hydrated silica (SiO2) spheroids, which provides us with a unique nano-scaled mineraloid with properties unlike those of other amorphous materials like glass. Opals from different localities were studied at high pressure using a diamond anvil cell to apply pressure and Raman spectroscopy to look at changes in bonding as pressure was increased. We first tested different samples from Virgin Valley, NV, Spencer, ID, Juniper Ridge, OR, and Australia, which contain varying amounts of water at ambient conditions, using Raman spectroscopy to determine if they were opal-CT (semicrystalline cristobalite-trydimite volcanic origin) or opal-A (amorphous sedimentary origin). We then used x-ray diffraction and Raman spectroscopy in a diamond anvil cell to see how their bonding and structure changed under compression and to determine what effect water content had on their high pressure behavior. Comparison of our results on opal to other high pressure studies of amorphous materials like glass has implications from a geological and materials science standpoint.

  19. HIGH PRESSURE COAL COMBUSTON KINETICS PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Stefano Orsino

    2005-03-30

    As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two series of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No.8 and Illinois No.6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No.8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical

  20. Dynamism or Disorder at High Pressures?

    Science.gov (United States)

    Angel, R. J.; Bismayer, U.; Marshall, W. G.

    2002-12-01

    Phase transitions in minerals at elevated temperatures typically involve dynamics as a natural consequence of the increase in thermal energy available to the system. Classic examples include quartz, cristobalite, and carbonates in which the high-temperature, high symmetry phase is dynamically disordered. This disorder has important thermodynamic consequences, including displacement and curvature of phase boundaries (e.g. calcite-aragonite). In other minerals such as clinopyroxenes and anorthite feldspar, the dynamic behaviour is restricted to the neighbourhood of the phase transition. The fundamental question is whether increasing pressure generally suppresses such dynamic behaviour (as in anorthite; Angel, 1988), or not. In the latter case it must be included in thermodynamic models of high-pressure phase equilibria and seismological modelling of the mantle; the potential dynamics and softening in stishovite may provide the critical observational constraint on the presence or otherwise of free silica in the lower mantle. We have continued to use the lead phosphate as a prototype ferroelastic in which to understand dynamic behaviour, simply because its dynamics and transition behaviour is far better characterised than any mineral. Furthermore, the phase transition is at a pressure where experimental difficulties do not dominate the experimental results. Our previous neutron diffraction study (Angel et al., 2001) revealed that some disorder, either dynamic or static, is retained in the high-symmetry, high-pressure phase just above the phase transition. New neutron diffraction data on the pure material now suggests that this disorder slowly decreases with increasing pressure until at twice the transition pressure it is ordered. Further data for doped material provides insights into the nature of this disorder. Angel (1988) Amer. Mineral. 73:1114. Angel et al (2001) J PhysC 13: 5353.

  1. Sleep duration's association with diet, physical activity, mental status, and weight among Korean high school students.

    Science.gov (United States)

    Lee, Jounghee

    2017-01-01

    Sleep deprivation is a critical public health problem, especially in Korean adolescents. This study aimed to identify the association between sleep duration and dietary behaviors, physical activity, mental status, and nutritional status among high school students in South Korea. Based on the data collected from the 2014 Korea Youth Risk Behavior Web-based Survey, 31,407 high school students who met the inclusion criteria were selected and the association between sleep duration and selected health risk factors was identified using multivariable logistic regression models. The average daily sleep duration was 5.7 hours, and the mean BMI was 21.3 kg/m2. Participants with shorter durations of sleep (=7 hours of sleep) were more likely to feel sad or hopeless (adjusted OR, 1.09; 95% CI, 1.00-1.18), have suicidal ideation (adjusted OR, 1.13; 95% CI, 1.01-1.27), and feel much or very much stressed (adjusted OR, 1.82; 95% CI, 1.66-2.00). Moreover, shorter sleep was associated with less frequent muscle-strengthening exercises, >=3 times per week (adjusted OR, 0.86; 95% CI, 0.78-0.94), and more frequent cracker consumption, >=3 times per week (adjusted OR, 1.24; 95% CI, 1.13-1.35). High school students in South Korea suffer from extreme sleep deprivation; only 16% of the students were found to have >=7 hours of sleep during weekdays. Sleep education should be provided to students to improve their physical and mental health.

  2. High pressure photoinduced ring opening of benzene

    International Nuclear Information System (INIS)

    Ciabini, Lucia; Santoro, Mario; Bini, Roberto; Schettino, Vincenzo

    2002-01-01

    The chemical transformation of crystalline benzene into an amorphous solid (a-C:H) was induced at high pressure by employing laser light of suitable wavelengths. The reaction was forced to occur at 16 GPa, well below the pressure value (23 GPa) where the reaction normally occurs. Different laser sources were used to tune the pumping wavelength into the red wing of the first excited singlet state S 1 ( 1 B 2u ) absorption edge. Here the benzene ring is distorted, presenting a greater flexibility which makes the molecule unstable at high pressure. The selective pumping of the S 1 level, in addition to structural considerations, was of paramount importance to clarify the mechanism of the reaction

  3. Sleep health, messaging, headaches, and academic performance in high school students.

    Science.gov (United States)

    Pecor, Keith; Kang, Lilia; Henderson, Matthew; Yin, Sunny; Radhakrishnan, Varsha; Ming, Xue

    2016-06-01

    We tested for associations of bedtime, sleep duration, instant messaging, and chronic headaches with hypersomnolence and academic performance in a sample of high school students in New Jersey, USA. Students were surveyed anonymously and asked to report their sleep and messaging habits, headache status, and overall grades. We found that greater hypersomnolence was associated with later bedtimes, shorter sleep durations, and the presence of chronic headaches, but not with messaging after lights out. Also, we found that academic performance was lower in students who messaged after lights out, but it was not affected by headache status, bedtime, or sleep duration. These results are consistent with other studies that have demonstrated associations between headaches and hypersomnolence and between instant messaging habits and academic performance. They also add to a growing literature on the relationships among use of electronic devices, sleep health, and academic performance by adolescents. Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  4. Advanced Diagnostics for High Pressure Spray Combustion.

    Energy Technology Data Exchange (ETDEWEB)

    Skeen, Scott A.; Manin, Julien Luc; Pickett, Lyle M.

    2014-06-01

    The development of accurate predictive engine simulations requires experimental data to both inform and validate the models, but very limited information is presently available about the chemical structure of high pressure spray flames under engine- relevant conditions. Probing such flames for chemical information using non- intrusive optical methods or intrusive sampling techniques, however, is challenging because of the physical and optical harshness of the environment. This work details two new diagnostics that have been developed and deployed to obtain quantitative species concentrations and soot volume fractions from a high-pressure combusting spray. A high-speed, high-pressure sampling system was developed to extract gaseous species (including soot precursor species) from within the flame for offline analysis by time-of-flight mass spectrometry. A high-speed multi-wavelength optical extinction diagnostic was also developed to quantify transient and quasi-steady soot processes. High-pressure sampling and offline characterization of gas-phase species formed following the pre-burn event was accomplished as well as characterization of gas-phase species present in the lift-off region of a high-pressure n-dodecane spray flame. For the initial samples discussed in this work several species were identified, including polycyclic aromatic hydrocarbons (PAH); however, quantitative mole fractions were not determined. Nevertheless, the diagnostic developed here does have this capability. Quantitative, time-resolved measurements of soot extinction were also accomplished and the novel use of multiple incident wavelengths proved valuable toward characterizing changes in soot optical properties within different regions of the spray flame.

  5. Cobalt ferrite nanoparticles under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Saccone, F. D.; Ferrari, S.; Grinblat, F.; Bilovol, V. [Instituto de Tecnologías y Ciencias de la Ingeniería, “Ing. H. Fernández Long,” Av. Paseo Colón 850 (1063), Buenos Aires (Argentina); Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Fisica Aplicada, Institut Universitari de Ciència dels Materials, Universitat de Valencia, c/ Doctor Moliner 50, E-46100 Burjassot, Valencia (Spain); Agouram, S. [Departamento de Física Aplicada y Electromagnetismo, Universitat de València, 46100 Burjassot, Valencia (Spain)

    2015-08-21

    We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20–27 GPa to 7.5–12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B{sub 0} = 204 GPa) is considerably larger than the value previously reported for bulk CoFe{sub 2}O{sub 4} (B{sub 0} = 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B{sub 0} = 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible.

  6. Utility of home sleep apnea testing in high-risk veterans.

    Science.gov (United States)

    Cairns, Alyssa; Sarmiento, Kathleen; Bogan, Richard

    2017-09-01

    Many Veterans Affairs Medical Centers (VAMCs) have implemented home sleep apnea testing (HSAT) in lieu of traditional in-lab testing to establish a timely and cost-sensitive diagnosis of obstructive sleep apnea (OSA). However, concern remains for the sensitivity and specificity of said technology in this population as many veterans are at increased risk for many of the comorbid conditions that can limit the accuracy of HSAT results. Hence, the purpose of this study is to evaluate rate of incongruent outcomes (e.g., negative HSAT results despite high clinical symptomology) as well as differences in study quality metrics and predictors of OSA between veteran sleep patients and general sleep patients being evaluated by a home sleep test. A random sample of HSAT outcomes from 1500 veterans and 1500 general sleep clinic patients was retrieved from a repository of anonymized HSAT outcomes from 2009 to 2013. General sleep clinic data were from patients referred for home sleep testing from a variety of clinical practices across North America, whereas VAMC patients were tested using a central dissemination process. All patients were tested for OSA using the Apnea Risk and Evaluation System (ARES), an HSAT that simultaneously records airflow, pulse oximetry, snoring, accelerometry, and EEG. Sample differences and rates of comorbidities, HSAT outcomes, predictors of OSA, and pretest OSA risk information were evaluated between groups. The presence of OSA was defined as an apnea-hypopnea index (AHI; using 4% desaturation criterion) of ≥5 and ≥15 events per hour. Sample differences in predictors of OSA were evaluated using logistic multiple regression. Veterans (91.3% male) were more likely to report comorbidities, especially depression, insomnia, hypertension, diabetes, restless legs syndrome (RLS), and use of sleep and pain medications compared to general sleep clinic patients (57.1% male). Despite differences in the rate of medical comorbidities, no differences were

  7. Sleep Apnea Related Risk of Motor Vehicle Accidents is Reduced by Continuous Positive Airway Pressure: Swedish Traffic Accident Registry Data

    Science.gov (United States)

    Karimi, Mahssa; Hedner, Jan; Häbel, Henrike; Nerman, Olle; Grote, Ludger

    2015-01-01

    Study Objectives: Obstructive sleep apnea (OSA) is associated with an increased risk of motor vehicle accidents (MVAs). The rate of MVAs in patients suspected of having OSA was determined and the effect of continuous positive airway pressure (CPAP) was investigated. Design: MVA rate in patients referred for OSA was compared to the rate in the general population using data from the Swedish Traffic Accident Registry (STRADA), stratified for age and calendar year. The risk factors for MVAs, using demographic and polygraphy data, and MVA rate before and after CPAP were evaluated in the patient group. Setting: Clinical sleep laboratory and population based control (n = 635,786). Patients: There were 1,478 patients, male sex 70.4%, mean age 53.6 (12.8) y. Interventions: CPAP. Measurements and Results: The number of accidents (n = 74) among patients was compared with the expected number (n = 30) from a control population (STRADA). An increased MVA risk ratio of 2.45 was found among patients compared with controls (P accident risk was most prominent in the elderly patients (65–80 y, seven versus two MVAs). In patients, driving distance (km/y), EDS (Epworth Sleepiness score ≥ 16), short habitual sleep time (≤ 5 h/night), and use of hypnotics were associated with increased MVA risk (odds ratios 1.2, 2.1, 2.7 and 2.1, all P ≤ 0.03). CPAP use ≥ 4 h/night was associated with a reduction of MVA incidence (7.6 to 2.5 accidents/1,000 drivers/y). Conclusions: The motor vehicle accident risk in this large cohort of unselected patients with obstructive sleep apnea suggests a need for accurate tools to identify individuals at risk. Sleep apnea severity (e.g., apnea-hypopnea index) failed to identify patients at risk. Citation: Karimi M, Hedner J, Häbel H, Nerman O, Grote L. Sleep apnea related risk of motor vehicle accidents is reduced by continuous positive airway pressure: Swedish traffic accident registry data. SLEEP 2015;38(3):341–349. PMID:25325460

  8. Sounding experiments of high pressure gas discharge

    International Nuclear Information System (INIS)

    Biele, Joachim K.

    1998-01-01

    A high pressure discharge experiment (200 MPa, 5·10 21 molecules/cm 3 , 3000 K) has been set up to study electrically induced shock waves. The apparatus consists of the combustion chamber (4.2 cm 3 ) to produce high pressure gas by burning solid propellant grains to fill the electrical pump chamber (2.5 cm 3 ) containing an insulated coaxial electrode. Electrical pump energy up to 7.8 kJ at 10 kV, which is roughly three times of the gas energy in the pump chamber, was delivered by a capacitor bank. From the current-voltage relationship the discharge develops at rapidly decreasing voltage. Pressure at the combustion chamber indicating significant underpressure as well as overpressure peaks is followed by an increase of static pressure level. These data are not yet completely understood. However, Lorentz forces are believed to generate pinching with subsequent pinch heating, resulting in fast pressure variations to be propagated as rarefaction and shock waves, respectively. Utilizing pure axisymmetric electrode initiation rather than often used exploding wire technology in the pump chamber, repeatable experiments were achieved

  9. High Pressure Inactivation of HAV within Mussels

    Science.gov (United States)

    The potential of hepatitis A virus (HAV) to be inactivated within Mediterranean mussels (Mytilus galloprovincialis) and blue mussels (Mytilus edulis) by high pressure processing was evaluated. HAV was bioaccumulated within mussels to approximately 6-log10 PFU by exposure of mussels to HAV-contamina...

  10. Teaming Up Against High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    2012-09-04

    This podcast is based on the September 2012 CDC Vital Signs report. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.  Created: 9/4/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 9/4/2012.

  11. High pressure and synchrotron radiation satellite workshop

    Energy Technology Data Exchange (ETDEWEB)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A

    2006-07-01

    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations.

  12. Study of ceramics sintering under high pressures

    International Nuclear Information System (INIS)

    Kunrath Neto, A.O.

    1990-01-01

    A systematic study was made on high pressure sintering of ceramics in order to obtain materials with controlled microstructure, which are not accessible by conventional methods. Some aspects with particular interest were: to achieve very low porosity, with fine grains; to produce dispersed metastable and denser phases which can act as toughening agents; the study of new possibilities for toughening enhancement. (author)

  13. Analysis of high-pressure safety valves

    NARCIS (Netherlands)

    Beune, A.

    2009-01-01

    In presently used safety valve sizing standards the gas discharge capacity is based on a nozzle flow derived from ideal gas theory. At high pressures or low temperatures real gas effects can no longer be neglected, so the discharge coefficient corrected for flow losses cannot be assumed constant

  14. High pressure studies of planetary matter

    International Nuclear Information System (INIS)

    Ross, M.

    1989-06-01

    Those materials which are of greatest interest to the physics of the deep planetary interiors are Fe, H 2 , He and the Ices. These are sufficiently diverse and intensively studied to offer an overview of present day high pressure research. 13 refs., 1 fig

  15. High pressure and synchrotron radiation satellite workshop

    International Nuclear Information System (INIS)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A.

    2006-01-01

    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations

  16. Effects of 12 months continuous positive airway pressure on sympathetic activity related brainstem function and structure in obstructive sleep apnea.

    Directory of Open Access Journals (Sweden)

    Luke Anthony Henderson

    2016-03-01

    Full Text Available Muscle sympathetic nerve activity (MSNA is greatly elevated in patients with obstructive sleep apnoea (OSA during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 subjects with OSA prior to and following 6 and 12 months of continuous positive airway pressure (CPAP treatment. We found that 6 and 12 months of CPAP treatment significantly reduced the elevated resting MSNA in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MNSA likely due to its effects on restoring brainstem structure and function.

  17. Effects of continuous positive airway pressure on hemorheology and serum inflammatory factors in patients with obstructive sleep apnea hypopnea syndrome

    Directory of Open Access Journals (Sweden)

    Ye-Jun Liu

    2016-02-01

    Full Text Available Objective: To investigate the effects of continuous positive airway pressure (CPAP on hemorheology and serum inflammatory factors in patients with obstructive sleep apnea hypopnea syndrome (OSAHS. Methods: A total of 87 patients with moderate and severe OSAHS from Department of Otolaryngology-Head and Neck Surgery of South Central Hospital of Wuhan University and Qianjiang Central Hospital were selected as research objects in the treatment group, while 37 healthy individuals were chosen as objects in the control group. The changes of hemorheology indexes including hematocrit (HCT, whole blood viscosity, platelet aggregation (PAG and endothelin (ET as well as serum inflammatory factors including interleukin-6 (IL-6, IL-18 and tumor necrosis factor-α (TNF-α were measured in the control group and the treatment group, and comparisons involving these indexes were made between the two groups. Results: Before treatment, the hemorheology indexes HCT, whole blood viscosity (high, medium and low sheer rates, PAG and ET as well as the inflammatory factors IL-6, IL-18 and TNF-α levels were significantly higher than those in the control group; after CPAP treatment, all these indexed mentioned above in the treatment group were significantly decreased compared with before treatment. Conclusion: CPAP treatment has a reliable therapeutic effect on OSAHS patients, which can obviously improve the hemorheology and largely reduce the inflammatory response.

  18. High hydrostatic pressure processing of tropical fruits.

    Science.gov (United States)

    Lopes, Maria Lúcia M; Valente Mesquita, Vera L; Chiaradia, Ana Cristina N; Fernandes, Antônio Alberto R; Fernandes, Patricia M B

    2010-02-01

    Interest in the nonthermal method of high hydrostatic pressure (HHP) for food preservation has increased recently due to the possibility of inactivating microorganisms and enzymes while maintaining product sensorial and nutritional properties. This work deals with HHP use for the preservation of tropical fruit products. HHP is shown to be a practical approach to obtaining high-quality tropical fruit products that are both nutritive and safe.

  19. High pressure neutron powder diffraction at LANSCE

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1994-01-01

    By making use of the recently developed ''Paris-Edinburgh'' high pressure cell, the author has successfully performed neutron powder experiments to 10GPa at ambient temperature. Results for the structural compression of the high Tc 1223-Hg superconductor to 9.2 GPa, the compression and possible hydrogen bond formation in brucite, Mg(OD) 2 , to 9.3 GPa, and the molecular reorientation in nitromethane to 5.5 GPa will be presented

  20. High temperature and high pressure equation of state of gold

    International Nuclear Information System (INIS)

    Matsui, Masanori

    2010-01-01

    High-temperature and high-pressure equation of state (EOS) of Au has been developed using measured data from shock compression up to 240 GPa, volume thermal expansion between 100 and 1300 K and 0 GPa, and temperature dependence of bulk modulus at 0 GPa from ultrasonic measurements. The lattice thermal pressures at high temperatures have been estimated based on the Mie-Grueneisen-Debye type treatment with the Vinet isothermal EOS. The contribution of electronic thermal pressure at high temperatures, which is relatively insignificant for Au, has also been included here. The optimized EOS parameters are K' 0T = 6.0 and q = 1.6 with fixed K 0T = 167 GPa, γ 0 = 2.97, and Θ 0 = 170 K from previous investigations. We propose the present EOS to be used as a reliable pressure standard for static experiments up to 3000K and 300 GPa.

  1. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita

    2016-01-01

    This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure and inter......This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure...... and intermolecular self-organization that typically determine transport and optical emission in π-conjugated oligomers and polymers. In this context, hydrostatic pressure through diamond anvil cells has proven to be an elegant tool to control structure and interactions without chemical intervention. This has been...... and intermolecular interactions on optical excitations, electron–phonon interaction, and changes in backbone conformations. This picture is connected to the optical high pressure studies of other π-conjugated systems and emerging x-ray scattering experiments from polyfluorenes which provides a structure-property map...

  2. Bullying as a risk for poor sleep quality among high school students in China.

    Directory of Open Access Journals (Sweden)

    Ying Zhou

    Full Text Available To determine whether involvement in bullying as a bully, victim, or bully-victim was associated with a higher risk of poor sleep quality among high school students in China.A cross-sectional study was conducted. A total of 23,877 high school students were surveyed in six cities in Guangdong Province. All students were asked to complete the adolescent health status questionnaire, which included the Chinese version of the Pittsburgh Sleep Quality Index (PSQI and bullying involvement. Descriptive statistics were used to evaluate sleep quality and the prevalence of school bullying. Multi-level logistic regression analyses were conducted to examine the association between being victimized and bullying others with sleep quality.Among the 23,877 students, 6,127 (25.66% reported having poor sleep quality, and 10.89% reported being involved in bullying behaviors. Of the respondents, 1,410 (5.91% were pure victims of bullying, 401 (1.68% were bullies and 784 (3.28% were bully-victims. Frequently being involved in bullying behaviors (being bullied or bullying others was related to increased risks of poor sleep quality compared with adolescents who were not involved in bullying behaviors. After adjusting for age, sex, and other confounding factors, the students who were being bullied (OR=2.05, 95%CI=1.81-2.32, bullied others (OR=2.30, 95%CI=1.85-2.86 or both (OR=2.58, 95%CI=2.20-3.03 were at a higher risk for poor sleep quality.Poor sleep quality among high school students is highly prevalent, and school bullying is prevalent among adolescents in China. The present results suggested that being involved in school bullying might be a risk factor for poor sleep quality among adolescents.

  3. Bullying as a risk for poor sleep quality among high school students in China.

    Science.gov (United States)

    Zhou, Ying; Guo, Lan; Lu, Ci-yong; Deng, Jian-xiong; He, Yuan; Huang, Jing-hui; Huang, Guo-liang; Deng, Xue-qing; Gao, Xue

    2015-01-01

    To determine whether involvement in bullying as a bully, victim, or bully-victim was associated with a higher risk of poor sleep quality among high school students in China. A cross-sectional study was conducted. A total of 23,877 high school students were surveyed in six cities in Guangdong Province. All students were asked to complete the adolescent health status questionnaire, which included the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) and bullying involvement. Descriptive statistics were used to evaluate sleep quality and the prevalence of school bullying. Multi-level logistic regression analyses were conducted to examine the association between being victimized and bullying others with sleep quality. Among the 23,877 students, 6,127 (25.66%) reported having poor sleep quality, and 10.89% reported being involved in bullying behaviors. Of the respondents, 1,410 (5.91%) were pure victims of bullying, 401 (1.68%) were bullies and 784 (3.28%) were bully-victims. Frequently being involved in bullying behaviors (being bullied or bullying others) was related to increased risks of poor sleep quality compared with adolescents who were not involved in bullying behaviors. After adjusting for age, sex, and other confounding factors, the students who were being bullied (OR=2.05, 95%CI=1.81-2.32), bullied others (OR=2.30, 95%CI=1.85-2.86) or both (OR=2.58, 95%CI=2.20-3.03) were at a higher risk for poor sleep quality. Poor sleep quality among high school students is highly prevalent, and school bullying is prevalent among adolescents in China. The present results suggested that being involved in school bullying might be a risk factor for poor sleep quality among adolescents.

  4. The high-pressure behavior of bloedite

    DEFF Research Database (Denmark)

    Comodi, Paola; Nazzareni, Sabrina; Balic Zunic, Tonci

    2014-01-01

    High-pressure single-crystal synchrotron X‑ray diffraction was carried out on a single crystal of bloedite [Na2Mg(SO4)24H2O] compressed in a diamond-anvil cell. The volume-pressure data, collected up to 11.2 GPa, were fitted by a second- and a third-order Birch-Murnaghan equation of state (EOS....... Pressure decreases significantly the distortion of Na coordination. Up to 10 GPa, the donor-acceptor oxygen distances decrease significantly and the difference between the two water molecules decreases with an increase in the strengths of hydrogen bonds. At the same time, the bond lengths from Na and Mg...... to O atoms of the water molecules decrease faster than other bonds to these cations suggesting that there is a coupling between the Na-Ow and Mg-Ow bond strengths and the “hydrogen transfer” to acceptor O atoms....

  5. Study into the use of continuous positive airway pressure in obstructive sleep apnoea-hypopnoea syndrome patients with daytime drowsiness

    Directory of Open Access Journals (Sweden)

    Clélia Maria Ribeiro Franco

    2009-03-01

    Full Text Available Background: Obstructive sleep apnoea-hypopnoea syndrome (OSAHS is a respiratory disorder with high morbidity and mortality. Continuous positive airway pressure (CPAP is the most commonly prescribed conservative treatment for adults with OSAHS. CPAP therapy normalises or decreases OSAHS symptoms and can reduce and prevent OSAHS complications. Aims: To evaluate adherence to nasal CPAP treatment and CPAP impact on daytime drowsiness. Method: A sample of 20 patients evaluated for daytime drowsiness using the Epworth sleepiness scale and interviewed for adherence to nasal CPAP use. Results: There was a significant decrease in the level of daytime sleepiness of the patients users of nasal CPAP (p=0.017; patients not using nasal CPAP experienced a decrease without statistical significance (p=0.162. 100% of CPAP users reported benefits and 50% of these reported related discomforts. Conclusions: Patients with OSAHS that use CPAP have a greater reduced level of sleepiness than those who do not use it. Resumo: Introdução: A síndroma da apneia-hipopneia obstrutiva do sono (SAHOS é um distúrbio respiratório de elevada morbimortalidade. A terapia com pressão positiva contínua das vias aéreas (CPAP representa o tratamento conservador mais prescrito para a SAHOS e tem o intuito de restabelecer a patência das vias aéreas, normalizando o índice de eventos respiratórios obstrutivos, corrigindo os sintomas. Objectivo: Avaliar o impacto do uso do CPAP nasal sobre a hipersonia diurna em portadores de SAHOS. Método: Amostra de vinte doentes portadores de SAHOS diagnosticados por estudo de polissonografia de noite inteira, usuários ou não de CPAP nasal, todos avaliados quanto à hipersonia diurna através da escala de sonolência de Epworth. Resultados: O decréscimo do nível de sonolência diurna dos usuários de CPAP nasal foi significante (p=0,017, enquanto para não usuários de CPAP nasal a m

  6. Adolescents' sleep in low-stress and high-stress (exam) times: a prospective quasi-experiment

    NARCIS (Netherlands)

    Dewald, J.F.; Meijer, A.M.; Oort, F.J.; Kerkhof, G.A.; Bögels, S.M.

    2014-01-01

    This prospective quasi-experiment (N=175; mean age: 15.14 years) investigates changes in adolescents' sleep from low-stress (regular school week) to high-stress times (exam week) and examines the (moderating) role of chronic sleep reduction, baseline stress, and gender. Sleep was monitored over

  7. Adolescents' Sleep in Low-Stress and High-Stress (Exam) Times: A Prospective Quasi-Experiment

    NARCIS (Netherlands)

    Dewald, Julia F.; Meijer, Anne Marie; Oort, Frans J.; Kerkhof, Gerard A.; Bögels, Susan M.

    2014-01-01

    This prospective quasi-experiment (N = 175; mean age = 15.14 years) investigates changes in adolescents' sleep from low-stress (regular school week) to high-stress times (exam week), and examines the (moderating) role of chronic sleep reduction, baseline stress, and gender. Sleep was monitored over

  8. High Mallampati score, obesity and obstructive sleep apnea: triple insult to lung function?

    Directory of Open Access Journals (Sweden)

    Nazia Uzma

    2014-07-01

    Full Text Available The paper assesses the combined effect of high Mallampati score, obesity and obstructive sleep apnea (OSA on lung function as measured by spirometry. Our results showed that the combination of sleep apnea, obesity and high Mallampati score resulted in a degree of restriction that was significantly greater than that produced by each factor alone. These observations underscore the importance of factoring in the Mallampati score in the assessment of respiratory disease.

  9. Plasma apelin levels in obstructive sleep apnea and the effect of continuous positive airway pressure therapy.

    Science.gov (United States)

    Henley, David E; Buchanan, Fiona; Gibson, Rosemary; Douthwaite, Jennie A; Wood, Susan A; Woltersdorf, Wolfram W; Catterall, James R; Lightman, Stafford L

    2009-10-01

    Apelin is a peptide hormone with cardiovascular and glucose homeostasis properties, and obstructive sleep apnea (OSA) is complicated by cardiovascular and metabolic comorbidities. Plasma apelin has not been previously assessed in OSA. We investigated the response of plasma apelin to a 2-h 75 g oral glucose tolerance test (OGTT) and the effect of 3 months compliant continuous positive airway pressure (CPAP) therapy in 15 obese males with newly diagnosed OSA. Plasma apelin and serum cortisol were recorded 10 minutely, while serum insulin and glucose were measured 30 minutely. Ten subjects had plasma apelin measured at intervals across a 24-h period to investigate for circadian variation in apelin levels, and this was repeated following 3 months compliant CPAP therapy. Fasting (0.342+/-0.038 vs 0.288+/-0.024 ng/ml, P=0.04), 30 min (0.399+/-0.035 vs 0.312+/-0.036 ng/ml, P=0.007) and 120 min (0.402+/-0.030 vs 0.259+/-0.024 ng/ml, P<0.001) apelin levels were reduced following CPAP. The area under curve for apelin OGTT response was lower post-CPAP (44.1+/-3.3 vs 35.8+/-2.3 ng/ml per min, P<0.001). Mean OGTT apelin levels showed a significant treatment effect (P=0.006) and a time effect (P<0.001), and the effect of time was different pre- versus post-CPAP (P=0.005). No significant variability in apelin levels existed across the 24-h period at diagnosis. Lower levels were evident overnight following treatment (P=0.004). Improvements in insulin and glucose parameters and reduced cortisol levels were found post-CPAP. In summary, untreated OSA was associated with elevated plasma apelin levels, altered apelin secretory dynamics in response to oral glucose and lack of an apparent circadian variability, which was restored following CPAP.

  10. Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study.

    Directory of Open Access Journals (Sweden)

    Sébastien Baillieul

    Full Text Available Severe obstructive sleep apnoea (OSA can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients.In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m-2, apnoea-hypopnoea index = 46.3±11.7 events·h-1 and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment.Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5% and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment.Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences.

  11. Continuous positive air pressure improves orthonasal olfactory function of patients with obstructive sleep apnea.

    Science.gov (United States)

    Walliczek-Dworschak, Ute; Cassel, Werner; Mittendorf, Luisa; Pellegrino, Robert; Koehler, Ulrich; Güldner, Christian; Dworschak, Philipp Otto Georg; Hildebrandt, Olaf; Daniel, Hanna; Günzel, Thomas; Teymoortash, Afshin; Hummel, Thomas

    2017-06-01

    Recent studies have suggested that patients with obstructive sleep apnea (OSA) might be affected by olfactory impairment. However, more evidence is needed on the effect that OSA has on the chemical senses (olfaction and gustatory) of these patients, and whether continuous positive airway pressure (CPAP) treatment might help to reverse possible impairment. A prospective study was conducted with 44 OSA patients (17 female and 27 male, mean age 54 ± 9.9 years) who were diagnosed via polysomnography and eligible for CPAP treatment. Orthonasal olfactory and gustatory function was measured with the extended Sniffin' Sticks test battery and "taste strips," respectively, before and after CPAP treatment. Baseline olfaction was decreased in OSA patients and after CPAP therapy olfactory scores (odor threshold-discrimination-identification score [TDI]: baseline 29.4 ± 4.11 after CPAP 32.3 ± 4.82; p = 0.001; odor threshold [THR]: baseline 5.28 ± 1.69 after CPAP 6.78 ± 2.61; p = 0.000; odor identification [ID]: baseline 12.9 ± 1.95 after CPAP 13.6 ± 1.33; p = 0.013) improved significantly. In contrast, neither baseline taste function in OSA patients nor gustatory function after treatment seemed to be affected. Orthonasal olfactory function in patients with OSA improves under CPAP therapy; however, gustatory function is not impaired in OSA patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Rapid eye movements during sleep in mice: High trait-like stability qualifies rapid eye movement density for characterization of phenotypic variation in sleep patterns of rodents

    Directory of Open Access Journals (Sweden)

    Fulda Stephany

    2011-11-01

    Full Text Available Abstract Background In humans, rapid eye movements (REM density during REM sleep plays a prominent role in psychiatric diseases. Especially in depression, an increased REM density is a vulnerability marker for depression. In clinical practice and research measurement of REM density is highly standardized. In basic animal research, almost no tools are available to obtain and systematically evaluate eye movement data, although, this would create increased comparability between human and animal sleep studies. Methods We obtained standardized electroencephalographic (EEG, electromyographic (EMG and electrooculographic (EOG signals from freely behaving mice. EOG electrodes were bilaterally and chronically implanted with placement of the electrodes directly between the musculus rectus superior and musculus rectus lateralis. After recovery, EEG, EMG and EOG signals were obtained for four days. Subsequent to the implantation process, we developed and validated an Eye Movement scoring in Mice Algorithm (EMMA to detect REM as singularities of the EOG signal, based on wavelet methodology. Results The distribution of wakefulness, non-REM (NREM sleep and rapid eye movement (REM sleep was typical of nocturnal rodents with small amounts of wakefulness and large amounts of NREM sleep during the light period and reversed proportions during the dark period. REM sleep was distributed correspondingly. REM density was significantly higher during REM sleep than NREM sleep. REM bursts were detected more often at the end of the dark period than the beginning of the light period. During REM sleep REM density showed an ultradian course, and during NREM sleep REM density peaked at the beginning of the dark period. Concerning individual eye movements, REM duration was longer and amplitude was lower during REM sleep than NREM sleep. The majority of single REM and REM bursts were associated with micro-arousals during NREM sleep, but not during REM sleep. Conclusions Sleep

  13. Prevalence and correlates of delayed sleep phase in high school students.

    Science.gov (United States)

    Saxvig, Ingvild W; Pallesen, Ståle; Wilhelmsen-Langeland, Ane; Molde, Helge; Bjorvatn, Bjørn

    2012-02-01

    To investigate prevalence and correlates of delayed sleep phase, characterized by problems falling asleep in the evening and rising at adequate times in the morning, in a large sample of Norwegian high school students. A randomized sample of 1285 high school students (aged 16-19 years) participated in an internet based study answering questions about sleep habits, height, weight, smoking, alcohol use, school grades, and anxiety and depression symptoms. Delayed sleep phase was operationalized as difficulties falling asleep before 2 a.m. at least three nights per week together with much or very much difficulty waking up in the morning. The results show a prevalence of delayed sleep phase of 8.4%. In all, 68% of these students (5.7% of the total sample) also reported problems advancing their sleep period as well as one daytime consequence (oversleeping at least two days a week or experiencing much/very much sleepiness at school). Delayed sleep phase was associated with lower average school grades, smoking, alcohol usage, and elevated anxiety and depression scores. Delayed sleep phase appears to be common amongst Norwegian adolescents and is associated with negative outcomes such as lower average school grades, smoking, alcohol usage, and elevated anxiety and depression scores. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Longitudinal Outcomes of Start Time Delay on Sleep, Behavior, and Achievement in High School

    Science.gov (United States)

    Thacher, Pamela V.; Onyper, Serge V.

    2016-01-01

    Study Objectives: To establish whether sleep, health, mood, behavior, and academics improved after a 45-minute delay in high school start time, and whether changes persisted longitudinally. Methods: We collected data from school records and student self-report across a number of domains at baseline (May 2012) and at two follow-up time points (November 2012 and May 2013), at a public high school in upstate New York. Students enrolled during academic years (AY) 2011–2012 and 2012–2013 completed the Pittsburgh Sleep Quality Index; the DASS-21; the “Owl-Lark” Scale; the Daytime Sleepiness Index; and a brief self-report of health. Reports from school records regarding attendance, tardiness, disciplinary violations, and academic performance were collected for AY 2010–2011 through 2013–2014. Results: Students delayed but did not extend their sleep period; we found lasting improvements in tardiness and disciplinary violations after the start-time delay, but no changes to other variables. At the first follow-up, students reported 20 minutes longer sleep, driven by later rise times and stable bed times. At the second follow-up, students maintained later rise times but delayed bedtimes, returning total sleep to baseline levels. A delay in rise time, paralleling the delay in the start time that occurred, resulted in less tardiness and decreased disciplinary incidents, but larger improvements to sleep patterns may be necessary to affect health, attendance, sleepiness, and academic performance. Conclusions: Later start times improved tardiness and disciplinary issues at this school district. A delay in start time may be a necessary but not sufficient means to increase sleep time and may depend on preexisting individual differences. Commentary: A commentary on this article appears in this issue on page 267. Citation: Thacher PV, Onyper SV. Longitudinal outcomes of start time delay on sleep, behavior, and achievement in high school. SLEEP 2016;39(2):271–281. PMID

  15. Gel pillow designed specifically for obstructive sleep apnea treatment with continuous positive airway pressure.

    Science.gov (United States)

    Salvaggio, Adriana; Lo Bue, Anna; Isidoro, Serena Iacono; Romano, Salvatore; Marrone, Oreste; Insalaco, Giuseppe

    2016-01-01

    To determine whether the use of a gel pillow with side cutouts designed to accommodate a continuous positive airway pressure (CPAP) mask and reduce head temperature improves the efficacy of and adherence to auto-CPAP therapy. Twenty-three consecutive CPAP-naïve patients with obstructive sleep apnea were enrolled in the study. Patients were given an auto-CPAP machine with an appropriate CPAP mask and were instructed to use CPAP for 15 nights. They were instructed to sleep with their own pillow (the control pillow) from nights 1 to 5 and with either a foam pillow or a gel pillow, both of which had side cutouts, for 5 consecutive nights each, in random order. After night 15, auto-CPAP machine data were downloaded and patients rated their satisfaction with each pillow on a visual analog scale. Twenty-two patients completed the protocol. The pressures administered, residual apnea-hypopnea index, air leaks, and mean duration of CPAP use did not differ among the periods during which each pillow was used. Patients were significantly more satisfied with the gel pillow than with the control pillow and the foam pillow (p = 0.022 and p = 0.004, respectively), their level of satisfaction with the gel pillow correlating significantly with excessive daytime sleepiness (r2 = 0.19; p = 0.0443). Among obstructive sleep apnea patients treated with nasal CPAP, the use of a gel pillow with side cutouts appears to have no impact on treatment effectiveness. Nevertheless, such patients seem to prefer a gel pillow over other types of pillows. Determinar se o uso de um travesseiro de gel com recortes laterais para acomodar a máscara de continuous positive airway pressure (CPAP, pressão positiva contínua nas vias aéreas) e diminuir a temperatura em torno da cabeça melhora a eficácia do tratamento com auto-CPAP e a adesão dos pacientes ao tratamento. Foram incluídos no estudo 23 pacientes consecutivos com apneia obstrutiva do sono que nunca haviam recebido tratamento com CPAP. Os

  16. Strain engineered pyrochlore at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Rittman, Dylan R.; Turner, Katlyn M.; Park, Sulgiye; Fuentes, Antonio F.; Park, Changyong; Ewing, Rodney C.; Mao, Wendy L.

    2017-05-22

    Strain engineering is a promising method for next-generation materials processing techniques. Here, we use mechanical milling and annealing followed by compression in diamond anvil cell to tailor the intrinsic and extrinsic strain in pyrochlore, Dy2Ti2O7 and Dy2Zr2O7. Raman spectroscopy, X-ray pair distribution function analysis, and X-ray diffraction were used to characterize atomic order over short-, medium-, and long-range spatial scales, respectively, under ambient conditions. Raman spectroscopy and X-ray diffraction were further employed to interrogate the material in situ at high pressure. High-pressure behavior is found to depend on the species and concentration of defects in the sample at ambient conditions. Overall, we show that defects can be engineered to lower the phase transformation onset pressure by ~50% in the ordered pyrochlore Dy2Zr2O7, and lower the phase transformation completion pressure by ~20% in the disordered pyrochlore Dy2Zr2O7. These improvements are achieved without significantly sacrificing mechanical integrity, as characterized by bulk modulus.

  17. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  18. Adults with Attention Deficit Hyperactivity Disorder Report High Symptom Levels of Troubled Sleep, Restless Legs, and Cataplexy

    Directory of Open Access Journals (Sweden)

    Bjørn Bjorvatn

    2017-09-01

    Full Text Available Objective: To compare the occurrence of a spectrum of different self-reported sleep problems in adults with ADHD and a control group, and to study the impact of current ADHD medication use and clinical ADHD subtype.Method: Cross-sectional study of 268 clinically ascertained adult ADHD patients (DSM-IV criteria and 202 randomly selected controls. Sleep problems were self-reported using validated questions, partly from Global Sleep Assessment Questionnaire.Results: ADHD patients reported more sleep problems than controls: Lifetime occurrence of sleep problems (82.6 vs. 36.5%, hypnotics use (61.4 vs. 20.2%, current sleep duration below 6 h (26.6 vs. 7.6%, and symptoms/signs during the past 4 weeks of excessive daytime sleepiness, cataplexy, loud snoring, breathing pauses during sleep, restless legs, and periodic limb movements in sleep (significant odds ratios ranged from 1.82 to 14.55. Current ADHD medication use was associated with less cataplexy compared with not using medication. Patients with inattentive subtype reported better sleep quality and less restless legs than patients with hyperactive/impulsive subtypes.Conclusions: Adults with ADHD reported a very high occurrence of many different self-reported sleep problems, underlining the importance of screening for sleep disorders. Among the ADHD patients, medication use was not associated with more sleep-related symptoms, but in fact less cataplexy. When comparing ADHD subtypes, the inattentive subtype was associated with less sleep problems.

  19. Is There an Association between Sleeping Patterns and Other Environmental Factors with Obesity and Blood Pressure in an Urban African Population?

    Directory of Open Access Journals (Sweden)

    Sandra Pretorius

    Full Text Available Beyond changing dietary patterns, there is a paucity of data to fully explain the high prevalence of obesity and hypertension in urban African populations. The aim of this study was to determine whether other environmental factors (including sleep duration, smoking and physical activity are related to body anthropometry and blood pressure (BP. Data were collected on 1311 subjects, attending two primary health care clinics in Soweto, South Africa. Questionnaires were used to obtain data on education, employment, exercise, smoking and sleep duration. Anthropometric and BP measurements were taken. Subjects comprised 862 women (mean age 41 ± 16 years and mean BMI 29.9 ± 9.2 kg/m² and 449 men (38 ± 14 years and 24.8 ± 8.3 kg/m². In females, ANOVA showed that former smokers had a higher BMI (p 30 minutes was related to a lower BMI (β = -0.04, p30 minutes/day was related to lower systolic (β = -0.02, p<0.05 and lower diastolic BP (β = -0.02, p = 0.05. Longer night time sleep duration was associated with higher diastolic (β = 0.005, p<0.01 and systolic BP (β = 0.003, p<0.05 in females. No health benefits were noted for physical activity. These data suggest that environmental factors rarely collected in African populations are related, in gender-specific ways, to body anthropometry and blood pressure. Further research is required to fully elucidate these associations and how they might be translated into public health programs to combat high levels of obesity and hypertension.

  20. 7 CFR 58.219 - High pressure pumps and lines.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false High pressure pumps and lines. 58.219 Section 58.219....219 High pressure pumps and lines. High pressure lines may be cleaned-in-place and shall be of such construction that dead ends, valves and the high pressure pumps can be disassembled for hand cleaning. The high...

  1. Assessment Sleep Quality and its Relationship with Test Anxiety among High School Students in Qom- Iran

    Directory of Open Access Journals (Sweden)

    Saman barmeh ziyar

    2016-10-01

    Full Text Available Background Test anxiety is a special case of a general anxiety which is of particular importance in students, because students will be the future of the country and the society activists. On the other hand, sleep quality and sleep disorders, have correlation with ailments, poor performance, decreased quality of life and increase of associated costs; This study aimed to determine the quality of sleep and its relationship with test anxiety among students in Qom city, Iran. Materials and Methods This study was a cross-sectional study, which was performed among 250 students who were going to pass the exam preparation classes. In order to collect data Pittsburgh Sleep Quality Index (PSQI questionnaires and Test Anxiety Inventory (TAI questionnaire were used. Data were analyzed using SPSS-16 with descriptive statistics and statistical methods, independent t-test, ANOVA and Pearson correlation coefficient. Results In this study, 50% of participants were boys (n=125 and 50 percent were girls (n=125. 81.4% of subjects had poor sleep quality and 69.6% had average to high score for test anxiety. Based on the results of anxiety test and sleep quality index there was a significant correlation between anxiety and sleep quality with gender (P=0.003, r=0.447. Conclusion School children had poor sleep quality and high test anxiety, and due to their direct and significant correlation, attention to this category of students, especially for girls, is important. Therefore, anxiety and promoting sleep quality control programs are recommended in this group.

  2. Comparative effects of melatonin, zolpidem and diazepam on sleep, body temperature, blood pressure and heart rate measured by radiotelemetry in Wistar rats.

    Science.gov (United States)

    Mailliet, F; Galloux, P; Poisson, D

    2001-08-01

    The role of melatonin (MLT) in mediating the sleep-wake cycle has been previously suspected of indicating that this substance could be a candidate for a new generation of hypnotics. We investigated whether MLT acted as a sleep promoter or a modulator of sleep temporal timing related to cardiovascular and body temperature (Tb) adaptations to sleep induction. The pharmacological effects of MLT on sleep were compared with zolpidem (ZP) and diazepam (DZ). The radiotelemetry system was used to record the electrocorticogram [slow wave sleep (SWS), paradoxical sleep (PS)], Tb, blood pressure and heart rate in six Wistar rats. DZ (3 mg/kg and 6 mg/kg), ZP (1, 3, 5 and 10 mg/kg) and MLT (2.5 and 5 mg/kg) were delivered intraperitoneally during light (L) and dark (D) periods. MLT increased the number of sleep cycles (L: 30%, D: 110%) and total duration (P<0.05) of PS (L: 70%, D: 150%). In return, ZP (10 mg/kg) presented no effect during L but increased total (40%) and mean duration (37%) of SWS during the D period. DZ modified mean duration of SWS (L: -27%, D: +26%) and increased total duration of SWS (+47%). ZP and DZ induced a more pronounced decrease in Tb than MLT but only DZ induced tachycardia and hypertension. We showed that MLT could not promote sleep and its cardiovascular adaptations despite hypothermia, but modulated the period of ultradian sleep cycles. DZ and ZP promoted sleep and induced hypothermia during the D period. Only DZ disrupted sleep architecture and induced adverse effects on cardiovascular parameters.

  3. Inspection technology for high pressure pipes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae H.; Lee, Jae C.; Eum, Heung S.; Choi, Yu R.; Moon, Soon S.; Jang, Jong H

    2000-02-01

    Various kinds of defects are likely to be occurred in the welds of high pressure pipes in nuclear power plants. Considering the recent accident of Zuruga nuclear power plant in Japan, reasonable policy is strongly requested for the high pressure pipe integrity. In this study, we developed the technologies to inspect pipe welds automatically. After development of scanning robot prototype in the first research year, we developed and implemented the algorithm of automatic tracking of the scanning robot along the weld line of the pipes. We use laser slit beam on weld area and capture the image using digital camera. Through processing of the captures image, we finally determine the weld line automatically. In addition, we investigated a new technology on micro systems for developing micro scanning robotic inspection of the pipe welds. The technology developed in this study is being transferred to the industry. (author)

  4. High pressure injection injuries: an overview.

    Science.gov (United States)

    Fialkov, J A; Freiberg, A

    1991-01-01

    Injuries resulting from the use of high pressure injectors and spray guns are relatively rare; however, the potential tissue damage caused by the injury as well as the extent of the injury itself may go unrecognized by the primary physician. The purpose of this paper is to inform the emergency physician of the nature and standard management of this type of injury. A basic understanding of the pathophysiology of the high pressure injection injury (HPII) is essential in avoiding the mistakes in management that have been reported in the literature. The emergency management of the HPII includes: evaluation and immobilization, tetanus and antimicrobial prophylaxis, supportive and resuscitative measures, analgesia, and minimizing the time to definitive surgical treatment.

  5. Stress concentration effects in high pressure components

    International Nuclear Information System (INIS)

    Aller, J.E.

    1990-01-01

    This paper examines the stress concentration effects of sideholes in thick walled, high pressure cylinders. It has been shown that the theoretical stress concentration factor at the intersection of a small crossbore in a closed end, thick walled cylinder varies between 3.0 and 4.0. Tests have shown that this effect can be greatly reduced in practice by carefully radiusing the bore intersection and autofrettaging the cylinder. It has also been shown that the minimum stress concentration factor occurs when the main bore and sidehole or crossbore have the same diameter, and the radius of the intersection is approximately equal to the sidehole radius. When the bore and sidehole intersection angle decreases from 90 degrees, the stress concentration factor increases significantly. Knowledge of these fundamental relationships can be used in maintaining, as well ad designing, high pressure equipment

  6. High Pressure Multicomponent Adsorption in Porous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1999-01-01

    We analyse adsorption of a multicomponent mixture at high pressure on the basis of the potential theory of adsorption. The adsorbate is considered as a segregated mixture in the external field produced by a solid adsorbent. we derive an analytical equation for the thickness of a multicomponent fi...... close to a dew point. This equation (asymptotic adsorption equation, AAE) is a first order approximation with regard to the distance from a phase envelope....

  7. Social stress induces high intensity sleep in rats

    NARCIS (Netherlands)

    Meerlo, P; Pragt, Bertrand J.; Daan, S

    1997-01-01

    We studied the effect of social stress on sleep electroencephalogram (EEG) in rats. Animals were subjected to a single social defeat by introducing them in the cage of an aggressive male conspecific for 1 h. The animals responded to the social conflict by a sharp increase in EEG slow-wave activity

  8. Path Dependency of High Pressure Phase Transformations

    Science.gov (United States)

    Cerreta, Ellen

    2017-06-01

    At high pressures titanium and zirconium are known to undergo a phase transformation from the hexagonal close packed (HCP), alpha-phase to the simple-hexagonal, omega-phase. Under conditions of shock loading, the high-pressure omega-phase can be retained upon release. It has been shown that temperature, peak shock stress, and texture can influence the transformation. Moreover, under these same loading conditions, plastic processes of slip and twinning are also affected by similar differences in the loading path. To understand this path dependency, in-situ velocimetry measurements along with post-mortem metallographic and neutron diffraction characterization of soft recovered specimens have been utilized to qualitatively understand the kinetics of transformation, quantify volume fraction of retained omega-phase and characterize the shocked alpha and omega-phases. Together the work described here can be utilized to map the non-equilibrium phase diagram for these metals and lend insight into the partitioning of plastic processes between phases during high pressure transformation. In collaboration with: Frank Addesssio, Curt Bronkhorst, Donald Brown, David Jones, Turab Lookman, Benjamin Morrow, Carl Trujillo, Los Alamos National Lab.; Juan Pablo Escobedo-Diaz, University of New South Wales; Paulo Rigg, Washington State University.

  9. High pressure phase transitions in Europous oxide

    International Nuclear Information System (INIS)

    Kremser, D.T.

    1982-01-01

    The pressure-volume relationship for EuO was investigated to 630 kilobars at room temperature with a diamond-anvil, high-pressure cell. Volumes were determined by x-ray diffraction; pressures were determined by the ruby R 1 fluorescence method. The preferred interpretation involves normal compression behavior for EuO, initially in the B1 (NaCl-type) structure, to about 280 kilobars. Between approx. =280 and approx. =350 kilobars a region of anomalous compressibility in which the volume drops continuously by approximately 2% is observed. A second-order electronic transition is proposed with the 6s band overlapping with the 4f levels, thereby reducing the volume of EuO without changing the structure. This is not a semiconductor-to-metal transition. In reflected light, this transition is correlated with a subtle and continuous change in color from brown-black to a light brown. The collapsed B1 phase (postelectronic transition) is stable between approx. =350 and approx. =400 kilobars. At about 400 kilobars the collapsed B1 structure transforms to the B2 (CsCl-type) structure, with a zero pressure-volume change of approximately 12 +/- 1.5%

  10. THE EFFECTIVENESS OF CHRONOTHERAPY IN HYPERTENSIVE PATIENTS WITH AN INSUFFICIENT DEGREE OF SLEEP-TIME SYSTOLIC BLOOD PRESSURE DECLINE

    Directory of Open Access Journals (Sweden)

    Petrenko O. V.

    2017-12-01

    Full Text Available Blood pressure (BP circadian rhythm violation, manifested as an insufficient degree of its sleep-time relative decline, is an independent cardiovascular risk factor. The main method of the correction is chronotherapeutic approach, when at least one antihypertensive drug is taken at bedtime. However, most researchers focus on normalizing the daily profile of systolic blood pressure (SBP and do not pay enough attention to changes in the daily profile of diastolic blood pressure (DBP and blood pressure in general. The aim of the study was to evaluate the influence of the chronotherapeutic approach on the SBP and DBP levels and the DBP daily profile in hypertensive patients with an insufficient degree of sleep-time relative SBP decline. The study included 12 patients with arterial hypertension (AH with an insufficient degree of sleep-time relative SBP decline. Participants were divided into two groups: group 1 included patients who take at least one antihypertensive drug at bedtime, group 2 – patients who take all antihypertensive drugs in the morning. All patients underwent 24-hour blood pressure monitoring using the computer system «Cardiosens» (KhAI Medica, Ukraine, with the oscillometric method of BP measuring when enrolling in the study and after 3 months. The type of SBP and DBP diurnal profile, the mean values of SBP, DBP and hyperbaric indices were determined and compared between groups 1 and 2 at each visit, as well as within groups between visits. The results showed that the SBP daily profile normalization in patients with insufficient degree of sleep-time relative SBP decline from group 2 was achieved only in 11 % of cases, and in group 1 SBP and DBP daily profile normalized in 1/3 patients. In some patients from group 2 SBP and DBP daily profile converted into the overdipper type, while in group 1 overdippers did not appear at the end of the study. It was concluded that conversion of daily DBP profile to overdipper as a consequence

  11. Energy Systems High-Pressure Test Laboratory | Energy Systems Integration

    Science.gov (United States)

    Facility | NREL Energy Systems High-Pressure Test Laboratory Energy Systems High-Pressure Test Laboratory In the Energy Systems Integration Facility's High-Pressure Test Laboratory, researchers can safely test high-pressure hydrogen components. Photo of researchers running an experiment with a hydrogen fuel

  12. Association of Sleep Duration with Obesity among US High School Students

    OpenAIRE

    Lowry, Richard; Eaton, Danice K.; Foti, Kathryn; McKnight-Eily, Lela; Perry, Geraldine; Galuska, Deborah A.

    2012-01-01

    Increasing attention is being focused on sleep duration as a potential modifiable risk factor associated with obesity in children and adolescents. We analyzed data from the national Youth Risk Behavior Survey to describe the association of obesity (self-report BMI ≥95th percentile) with self-reported sleep duration on an average school night, among a representative sample of US high school students. Using logistic regression to control for demographic and behavioral confounders, among female ...

  13. Sleep and your health

    Science.gov (United States)

    ... to perform basic functions. You may find it hard to concentrate or remember things. You may become moody and lash out at ... lead to high blood pressure and inflammation, two things that can ... often make it hard to sleep. They also can become worse after ...

  14. Hydrogen high pressure proportional drift detector

    International Nuclear Information System (INIS)

    Arefiev, A.; Balaev, A.

    1983-01-01

    The design and operation performances of a proportional drift detector PDD are described. High sensitivity of the applied PAD makes it possible to detect the neutron-proton elastic scattering in the energy range of recoil protons as low as 1 keV. The PDD is filled with hydrogen up to the pressure at 40 bars. High purity of the gas is maintained by a continuously operating purification system. The detector has been operating for several years in a neutron beam at the North Area of the CERN SPS

  15. CPAP therapy for patients with sleep apnea and type 2 diabetes mellitus improves control of blood pressure.

    Science.gov (United States)

    Lam, Jamie Chung Mei; Lai, Agnes Yuen Kwan; Tam, Terence Chi Chun; Yuen, Michele Mae Ann; Lam, Karen Siu Ling; Ip, Mary Sau Man

    2017-05-01

    Obstructive sleep apnea (OSA) is highly associated with type 2 diabetes mellitus (DM), and treatment of OSA may have a positive impact on cardiometabolic profile. This study investigates the effects of continuous positive airway pressure (CPAP) treatment on glycemic control and cardiometabolic parameters in patients with diabetes. Diabetic patients, who were newly diagnosed of OSA with an apnea hypopnea index (AHI) ≥15 and HbA1c ≥7%, were randomly assigned to either CPAP treatment or no treatment (control) for 3 months. Measurements included HbA1c, blood pressure, fasting glucose and lipids, urinary albumin, and peripheral arterial tonometry (to assess endothelial function). Sixty-four patients (52 men) were randomized, with mean (±SD) age of 55.0 ± 9.6 years, body mass index of 29.9 ± 5.3 kg/m 2 , HbA1c of 8.1 ± 1.1%, and AHI of 45.3 ± 23.2 events/h. In the intention-to-treat analysis, no significant change in HbA1c but reduction of systolic (10 mmHg (-18 to -2), p CPAP group compared to the control group. Excluding those with medication changes or initiated dietary program during the study period and those who dropped out, CPAP treatment decreased HbA1c (intervention group, n = 27; control group, n = 26) by 0.4% (-0.7 to -0.1), p = 0.027. In patients with type 2 DM and moderate to severe OSA, 3 months of CPAP therapy did not decrease HbA1c but lowered systolic and diastolic blood pressures. In view of a potentially limited effect size of CPAP treatment on glycemic control, sample size estimation for future randomized controlled studies must make adequate allowance for influence from external factors of medications/diet and CPAP use.

  16. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography.

    Directory of Open Access Journals (Sweden)

    Kate E Sprecher

    Full Text Available Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel electroencephalography (EEG during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18-65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson's coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

  17. Superconductivity from magnetic elements under high pressure

    International Nuclear Information System (INIS)

    Shimizu, Katsuya; Amaya, Kiichi; Suzuki, Naoshi; Onuki, Yoshichika

    2006-01-01

    Can we expect the appearance of superconductivity from magnetic elements? In general, superconductivity occurs in nonmagnetic metal at low temperature and magnetic impurities destroy superconductivity; magnetism and superconductivity are as incompatible as oil and water. Here, we present our experimental example of superconducting elements, iron and oxygen. They are magnetic at ambient pressure, however, they become nonmagnetic under high pressure, then superconductor at low temperature. What is the driving force of the superconductivity? Our understanding in the early stages was a simple scenario that the superconductive state was obtained as a consequence of an emergence of the nonmagnetic states. In both cases, we may consider another scenario for the appearance of superconductivity; the magnetic fluctuation mechanism in the same way as unconventional superconductors

  18. Sizing of high-pressure restriction orifices

    International Nuclear Information System (INIS)

    Casado Flores, E.

    1995-01-01

    Constant up-grading of power plants sometimes requires the modification of components which form part of suppliers' packages. In order to protect technology they have developed, however, the suppliers do not supply their calculation criteria. In order to reduce the costs of such improvements, and so as to be able to undertake the modification without having to rely on the original supplier, this paper describes the basic criteria applicable to the study of high-pressure restriction orifices, which can be considered to be representative of the components in question. The restriction orifices discussed are: - Insert - Multiplates in series with one perforation in each plate - Multiplates in series with several perforations in each plate For each type, an explanation of their sizing is given, together with the equations relating the corresponding flow and pressure drop. (Author)

  19. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg

    2013-01-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 ◦C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive...... media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells...... and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures...

  20. SrWO4 at high pressures

    International Nuclear Information System (INIS)

    Grzechnik, A.; Crichton, W.A.; Hanfland, M.

    2005-01-01

    Room-temperature high-pressure behaviour of SrWO 4 scheelite (I4 1 /a, Z=4) has been studied to 20.7 GPa in a diamond anvil cell using synchrotron angle-dispersive X-ray powder diffraction. Above 10 GPa, it transforms to the fergusonite structure (I2/a, Z=4). Both scheelite and fergusonite types are ordered superstructures of fluorite (Fm anti 3m, Z=4). There is no significant volume collapse at the scheelite-fergusonite phase transition. However, the compression data including both phases of strontium tungstate cannot be fitted by a common Birch-Murnaghan equation of state. An onset of decomposition into component oxides occurs at about 15 GPa. The pressure-induced transformations are irreversible. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Treatment of sleep central apnea with non-invasive mechanical ventilation with 2 levels of positive pressure (bilevel in a patient with myotonic dystrophy type 1

    Directory of Open Access Journals (Sweden)

    Ricardo Tera Akamine

    2014-06-01

    Bi-level positive airway pressure treatment at spontaneous/timed mode showed an improvement in snoring, apneas, and Epworth sleepiness scale decreased from 20 to 10. This case illustrates the beneficial effects of Bi-level positive airway pressure support in central sleep apnea syndrome of a patient with myotonic dystrophy type 1.

  2. [Influence of nasal continuous positive airway pressure on response to exercise in patients with obstructive sleep apnea syndrome].

    Science.gov (United States)

    Przybyłowski, Tadeusz; Bielicki, Piotr; Kumor, Marta; Hildebrand, Katarzyna; Maskey-Warzechowska, Marta; Wiwała, Joanna; Kościuch, Justyna; Korczyński, Piotr; Chazan, Ryszarda

    2006-01-01

    Obstructive sleep apnea syndrome (OSAS) patients are at risk of cardiovascular complications. The aim of this study was to assess the effect of treatment with continuous positive airway pressure (CPAP) on the response to symptom limited exercise test. twenty nine OSAS patients (1 F, 28 M), mean age 50.7+/-9.7 yrs with body mass index of 32.6+/-4.5 kg/m2 participated in the study. OSAS was diagnosed by overnight polysomnography. Incremental cardiopulmonary exercise test (CPET) on a treadmill was performed twice: before and after 2-3 weeks of regular treatment with CPAP. mean apnea + hypopnea index (AHI) before therapy was 57.6+/-12 h(-1). CPAP treatment did not change peak oxygen consumption (VO2max) (38.3+/-9.0 vs. 38.9+/-6.9 mlO2/kg/min, p=ns) or peak heart rate (153.4+/-21 min- vs. 155.5+/-22 min(-1), p=ns). There were no significant changes in ventilation or gas exchange variables. However, a decrease in peak systolic blood pressure from 194.5+/-24 mmHg to 186.7+/-27.9 mmHg (prate (at 1st minute and minutes 3 - 6) and mean arterial pressure (MAP) (minutes 4-7) with CPAP treatment was observed. Significant correlations between VO2max and AHI (r=-0,38, p<0,05); MAP at peak exercise and: AHI, mean oxygen saturation (SaO2) during sleep, minutes of sleep with SaO2<90% (T90); MAP at recovery (minutes 3-8) and T90 before CPAP treatment were also noted. OSAS patients are not limited on exercise. Treatment with nasal CPAP attenuates circulatory response to incremental exercise on a treadmill.

  3. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

    The current thesis studies experimentally the effect of high external pressure on high-T{sub c} superconductors. The structure and lattice dynamics of several members of the high-T{sub c} cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa{sub 2}Cu{sub 3}O{sub 6.55} samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa{sub 2}Cu{sub 4}O{sub 8}. A clear renormalization of some of the Raman phonons is seen below T{sub c} as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B{sub 1g}-like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa{sub 2}Cu{sub 3}O{sub 6+x}. At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group

  4. High pressure study of high-temperature superconductors

    International Nuclear Information System (INIS)

    Souliou, Sofia-Michaela

    2014-01-01

    The current thesis studies experimentally the effect of high external pressure on high-T c superconductors. The structure and lattice dynamics of several members of the high-T c cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T c superconductor YBa 2 Cu 3 O 6+x have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa 2 Cu 3 O 6.55 samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa 2 Cu 4 O 8 . A clear renormalization of some of the Raman phonons is seen below T c as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B 1g -like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa 2 Cu 3 O 6+x . At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group Imm2). The structural transition is clearly reflected in the high pressure

  5. Sleep Disrupts High-Level Speech Parsing Despite Significant Basic Auditory Processing.

    Science.gov (United States)

    Makov, Shiri; Sharon, Omer; Ding, Nai; Ben-Shachar, Michal; Nir, Yuval; Zion Golumbic, Elana

    2017-08-09

    The extent to which the sleeping brain processes sensory information remains unclear. This is particularly true for continuous and complex stimuli such as speech, in which information is organized into hierarchically embedded structures. Recently, novel metrics for assessing the neural representation of continuous speech have been developed using noninvasive brain recordings that have thus far only been tested during wakefulness. Here we investigated, for the first time, the sleeping brain's capacity to process continuous speech at different hierarchical levels using a newly developed Concurrent Hierarchical Tracking (CHT) approach that allows monitoring the neural representation and processing-depth of continuous speech online. Speech sequences were compiled with syllables, words, phrases, and sentences occurring at fixed time intervals such that different linguistic levels correspond to distinct frequencies. This enabled us to distinguish their neural signatures in brain activity. We compared the neural tracking of intelligible versus unintelligible (scrambled and foreign) speech across states of wakefulness and sleep using high-density EEG in humans. We found that neural tracking of stimulus acoustics was comparable across wakefulness and sleep and similar across all conditions regardless of speech intelligibility. In contrast, neural tracking of higher-order linguistic constructs (words, phrases, and sentences) was only observed for intelligible speech during wakefulness and could not be detected at all during nonrapid eye movement or rapid eye movement sleep. These results suggest that, whereas low-level auditory processing is relatively preserved during sleep, higher-level hierarchical linguistic parsing is severely disrupted, thereby revealing the capacity and limits of language processing during sleep. SIGNIFICANCE STATEMENT Despite the persistence of some sensory processing during sleep, it is unclear whether high-level cognitive processes such as speech

  6. Effects of continuous positive airway pressure on energy intake in obstructive sleep apnea: A pilot sham-controlled study

    OpenAIRE

    Shechter, Ari; Kovtun, Kyle; St-Onge, Marie-Pierre

    2016-01-01

    Obesity is among the leading risk factors for obstructive sleep apnea (OSA). A reciprocal relationship between obesity and OSA has been proposed, which may be due to excessive food intake. We conducted a pilot study to test the effects of continuous positive airway pressure (CPAP) on energy intake (EI) in OSA patients using a sham-controlled crossover design. In-laboratory total daily EI was assessed after 2 mo of active and sham CPAP. Four men were enrolled (age ± SEM: 51.8 ± 2.1 y; body mas...

  7. Effects of positive airway pressure therapy on cardiovascular and metabolic markers in males with obstructive sleep apnea.

    Science.gov (United States)

    Feliciano, A; Oliveira, M J; Cysneiros, A; Martinho, C; Reis, R P; Penque, D; Pinto, P; Bárbara, C

    Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular/metabolic complications. Some analytical parameters (homocysteine, glycemic and lipidic profiles) are recognized markers of these consequences. Limited data is available on the association of these markers and OSAS's severity/response to positive airway pressure therapy (PAP). In this prospective study we analyzed polysomnographic and analytical data of male patients admitted to sleep laboratory. The aim was to evaluate metabolic/cardiovascular markers in snorers and OSAS patients, to relate with sleep parameters and PAP response. One-hundred and three patients were included, and 73 (71%) were OSAS patients. OSAS patients were similar to snorers except for higher body mass index (BMI) and dyslipidemia. Severe OSAS patients showed higher glycemia, HbA1c, insulin, and insulin resistance, and lower HDL cholesterol in comparison to mild-moderate (pprofile and triglycerides were slightly correlated with OSAS severity. 46 OSAS patients were submitted to 6 months of PAP, with a statistical decrease in mean values of homocysteine, glycemia, total and LDL cholesterol (pprofiles changed significantly after 6 months of PAP therapy in OSAS, supporting its cardiovascular and metabolic protective effect. Our study has reinforced the importance of analytical cardiovascular/metabolic evaluation as complementary tool of diagnosis/treatment response in OSAS. Copyright © 2017 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.

  8. Brain reactivity differentiates subjects with high and low dream recall frequencies during both sleep and wakefulness.

    Science.gov (United States)

    Eichenlaub, Jean-Baptiste; Bertrand, Olivier; Morlet, Dominique; Ruby, Perrine

    2014-05-01

    The neurophysiological correlates of dreaming remain unclear. According to the "arousal-retrieval" model, dream encoding depends on intrasleep wakefulness. Consistent with this model, subjects with high and low dream recall frequency (DRF) report differences in intrasleep awakenings. This suggests a possible neurophysiological trait difference between the 2 groups. To test this hypothesis, we compared the brain reactivity (evoked potentials) of subjects with high (HR, N = 18) and low (LR, N = 18) DRF during wakefulness and sleep. During data acquisition, the subjects were presented with sounds to be ignored (first names randomly presented among pure tones) while they were watching a silent movie or sleeping. Brain responses to first names dramatically differed between the 2 groups during both sleep and wakefulness. During wakefulness, the attention-orienting brain response (P3a) and a late parietal response were larger in HR than in LR. During sleep, we also observed between-group differences at the latency of the P3a during N2 and at later latencies during all sleep stages. Our results demonstrate differences in the brain reactivity of HR and LR during both sleep and wakefulness. These results suggest that the ability to recall dreaming is associated with a particular cerebral functional organization, regardless of the state of vigilance.

  9. 30 CFR 57.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-pressure hose connections. 57.13021... Air and Boilers § 57.13021 High-pressure hose connections. Except where automatic shutoff valves are...-pressure hose lines of 3/4-inch inside diameter or larger, and between high-pressure hose lines of 3/4-inch...

  10. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V

    2002-01-01

    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  11. Longitudinal Outcomes of Start Time Delay on Sleep, Behavior, and Achievement in High School.

    Science.gov (United States)

    Thacher, Pamela V; Onyper, Serge V

    2016-02-01

    To establish whether sleep, health, mood, behavior, and academics improved after a 45-minute delay in high school start time, and whether changes persisted longitudinally. We collected data from school records and student self-report across a number of domains at baseline (May 2012) and at two follow-up time points (November 2012 and May 2013), at a public high school in upstate New York. Students enrolled during academic years (AY) 2011-2012 and 2012-2013 completed the Pittsburgh Sleep Quality Index; the DASS-21; the "Owl-Lark" Scale; the Daytime Sleepiness Index; and a brief self-report of health. Reports from school records regarding attendance, tardiness, disciplinary violations, and academic performance were collected for AY 2010-2011 through 2013-2014. Students delayed but did not extend their sleep period; we found lasting improvements in tardiness and disciplinary violations after the start-time delay, but no changes to other variables. At the first follow-up, students reported 20 minutes longer sleep, driven by later rise times and stable bed times. At the second follow-up, students maintained later rise times but delayed bedtimes, returning total sleep to baseline levels. A delay in rise time, paralleling the delay in the start time that occurred, resulted in less tardiness and decreased disciplinary incidents, but larger improvements to sleep patterns may be necessary to affect health, attendance, sleepiness, and academic performance. Later start times improved tardiness and disciplinary issues at this school district. A delay in start time may be a necessary but not sufficient means to increase sleep time and may depend on preexisting individual differences. A commentary on this article appears in this issue on page 267. © 2016 Associated Professional Sleep Societies, LLC.

  12. Sleep Duration, Sleep Quality, Body Mass Index, and Waist Circumference among Young Adults from 24 Low- and Middle-Income and Two High-Income Countries.

    Science.gov (United States)

    Peltzer, Karl; Pengpid, Supa

    2017-05-26

    Obesity and its comorbidities have emerged as a leading public health concern. The aim of this study was to explore the relationship between body mass index (BMI), waist circumference (WC) and sleep patterns, including duration and disturbances. A cross-sectional questionnaire survey and anthropometric measurements were conducted with undergraduate university students that were randomly recruited in 26 universities in 24 low- and middle-income and two high-income countries. The sample included 18,211 (42.1% male and 57.9% female, mean age 21.0 in male and 20.7 years in female students) undergraduate university students. The overall BMI was a mean of 22.5 kg/m² for men and 22.0 kg/m² for women, and the mean WC was 78.4 cm for men and 73.8 cm for women. More than 39% of the students reported short sleep duration (≤6 h/day) and over 30% reported moderate to extreme sleep problems. In a linear multivariable regression, adjusted for sociodemographic and lifestyle factors, short sleep duration was positively associated with BMI in both men and women, and was positively associated with WC among women but not among men. Sleep quality or problems among men were not associated with BMI, while among women mild sleep problems were inversely associated with BMI, and poor sleep quality or problems were positively associated with WC both among men and women. The study confirmed an association between short sleep duration and increased BMI and, among women, increased WC, and an association between poor sleep quality and increased WC but not BMI. Further, differences in the association between sleep characteristics and BMI and WC were found by region and country income.

  13. Role of Positive Airway Pressure Therapy for Obstructive Sleep Apnea in Patients With Stroke: A Randomized Controlled Trial

    Science.gov (United States)

    Gupta, Anupama; Shukla, Garima; Afsar, Mohammed; Poornima, Shivani; Pandey, Ravindra M.; Goyal, Vinay; Srivastava, Achal; Vibha, Deepti; Behari, Madhuri

    2018-01-01

    Study Objectives: Obstructive sleep apnea (OSA) is an independent risk factor for stroke. The objective of this study was to assess the effect of continuous positive airway pressure (CPAP) treatment on prevention of new vascular events among patients with stroke and OSA. Methods: Consecutive conscious patients presenting with first imaging-confirmed arterial stroke were included, 6 weeks or more after ictus. All patients underwent clinical and polysomnography (PSG) testing. Patients with an apnea-hypopnea index (AHI) of > 15 events/h were randomized to posttitration nightly CPAP treatment and non-CPAP (received best medical treatment) groups. On follow-up at 3, 6, and 12 months from randomization, evaluation was carried out for any new vascular events as the primary outcome measure, and for clinical stroke outcomes (using the Barthel Index and modified Rankin scale) and neuropsychological parameters as the secondary outcome measures. Results: Among the 679 patients with stroke who were screened, 116 reported for PSG, 83 had AHI > 15 events/h, and 70 (34 in CPAP and 36 in non-CPAP) were randomized. Thirteen patients could not be randomized because of a lack of CPAP devices. Four patients crossed over from the CPAP to the non-CPAP group. Age (mean age 53.41 ± 9.85 in CPAP versus 52.69 ± 13.23 years in non-CPAP, P = .81) and sex distribution (24 males in CPAP versus 33 males in non-CPAP, P = .79) were similar in both groups. At 12-month follow-up, there was 1 vascular event (3.33%) in the CPAP group and 6 events (15%) in the non-CPAP group (P = .23). Modified Rankin scale score improvement by ≥ 1 at 12-month follow-up was found in significantly more patients in the CPAP group than in the non-CPAP group (53% versus 27%). Conclusions: These findings suggest significantly better stroke outcomes and statistically nonsignificant favorable outcomes in terms of recurrence of vascular events for patients with stroke and OSA who use CPAP treatment. Clinical Trial

  14. Development and evaluation of a self-efficacy instrument for Japanese sleep apnea patients receiving continuous positive airway pressure treatment

    Directory of Open Access Journals (Sweden)

    Saito A

    2015-01-01

    Full Text Available Ayako Saito,1 Shigeko Kojima,2 Fumihiko Sasaki,3 Masamichi Hayashi,4 Yuki Mieno,4 Hiroki Sakakibara,5 Shuji Hashimoto1 1Department of Hygiene, School of Medicine, Fujita Health University, Toyoake, Japan; 2Department of Rehabilitation, Faculty of Health Sciences, Nihon Fukushi University, Handa, Japan; 3SDB Research Laboratory, Takaoka Clinic, Nagoya, Japan; 4Department of Internal Medicine, Division of Respiratory Medicine and Clinical Allergy, Fujita Health University, Toyoake, Japan; 5Tokushige Kokyuki Clinic, Nagoya, Japan Abstract: The purpose of this study was to develop and evaluate a self-efficacy instrument for Japanese obstructive sleep apnea (OSA patients treated with continuous positive airway pressure (CPAP. Analyzed subjects were 653 Japanese OSA patients (619 males and 34 females treated with CPAP at a sleep laboratory in a respiratory clinic in a Japanese city. Based on Bandura's social cognitive theory, the CPAP Self-Efficacy Questionnaire for Sleep Apnea in Japanese (CSESA-J was developed by a focus group of experts, using a group interview of OSA patients for the items of two previous self-efficacy scales for Western sleep apnea patients receiving CPAP treatment. CSESA-J has two subscales, one for self-efficacy and the other for outcome expectancy, and consists of a total of 15 items. Content validity was confirmed by the focus group. Confirmatory factor analysis showed that the factor loadings of self-efficacy and outcome expectancy were 0.47–0.76 and 0.41–0.92, respectively, for the corresponding items. CSESA-J had a significant but weak positive association with the General Self-Efficacy Scale, and a strong positive association with “Self-efficacy scale on health behavior in patients with chronic disease.” Cronbach’s alpha coefficient was 0.85 for the self-efficacy subscale and 0.89 for the outcome expectancy subscale. The intraclass correlation coefficient using data from the first and second measurements with

  15. 49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

  16. Recent progress in high-pressure studies on organic conductors

    Directory of Open Access Journals (Sweden)

    Syuma Yasuzuka and Keizo Murata

    2009-01-01

    Full Text Available Recent high-pressure studies of organic conductors and superconductors are reviewed. The discovery of the highest Tc superconductivity among organics under high pressure has triggered the further progress of the high-pressure research. Owing to this finding, various organic conductors with the strong electron correlation were investigated under high pressures. This review includes the pressure techniques using the cubic anvil apparatus, as well as high-pressure studies of the organic conductors up to 10 GPa showing extraordinary temperature and pressure dependent transport phenomena.

  17. Sleep quality and its relationship with quality of life among high-risk pregnant women (gestational diabetes and hypertension).

    Science.gov (United States)

    Saadati, Fatemeh; Sehhatiei Shafaei, Fahimeh; Mirghafourvand, Mozhgan

    2018-01-01

    Sleep is one of the most basic human requirements. This research aims at determining the status of sleep quality and its relationship with quality of life among high-risk pregnant women in Tabriz, Iran, in 2015. This research was a sectional study done on 364 qualified women in 28-36 weeks of pregnancy suffering from mild preeclampsia and gestational diabetes. The sampling was done as convenience. Personal-social-midwifery questionnaire, Pittsburg sleep quality, and quality of life in pregnancy (QOL-ORAV) were used for gathering data. Multivariate linear regression model was used for determining the relationship between sleep quality and its subsets with quality of life and controlling confounders. In the current study, the prevalence of sleep disturbance was 96.4%. Mean (SD) of the total score of sleep quality was 10.1 (4.1) and the total score of quality of life was 61.7 (17.3). According to Pearson's correlation test, there was statistically significant relationship between quality of life and sleep quality and all its subsets except sleep duration and use of sleep medication (p quality of life. The findings of current research show that sleep quality is low among high-risk pregnant women and quality of life is medium. So, it is necessary that required training is given by health cares for improving sleep quality and quality of life to mothers.

  18. Condensed matter at high shock pressures

    International Nuclear Information System (INIS)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Radousky, H.B.; Hamilton, D.

    1985-01-01

    Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N 2 , CO, SiO 2 -aerogel, H 2 O, and C 6 H 6 . The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab

  19. Commentary on differential-pressure measurements at high reference pressures

    International Nuclear Information System (INIS)

    Hasbrouck, R.T.; Noyes, R.P.

    1981-01-01

    Some practical approaches to the difficult problems in calibrating and implementing differential-pressure measurements are discussed. The data presented were gathered several years ago in separate investigations. An attempt is made to compare the results of these investigations to the common mode concept as described by Peter K. Stein in his publication, The Measurement of Differential Quantities - Problems and Approaches. Although one of these investigations involed a 10,000- to 20,000-psi reference-pressure gas measured at an ambient temperature and the other a classic /sup Δ/P flow measurement of cryogenic temperature, the problems encountered were the same

  20. Conformable pressure vessel for high pressure gas storage

    Science.gov (United States)

    Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

    2016-01-12

    A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

  1. Novel method for high-throughput phenotyping of sleep in mice.

    Science.gov (United States)

    Pack, Allan I; Galante, Raymond J; Maislin, Greg; Cater, Jacqueline; Metaxas, Dimitris; Lu, Shan; Zhang, Lin; Von Smith, Randy; Kay, Timothy; Lian, Jie; Svenson, Karen; Peters, Luanne L

    2007-01-17

    Assessment of sleep in mice currently requires initial implantation of chronic electrodes for assessment of electroencephalogram (EEG) and electromyogram (EMG) followed by time to recover from surgery. Hence, it is not ideal for high-throughput screening. To address this deficiency, a method of assessment of sleep and wakefulness in mice has been developed based on assessment of activity/inactivity either by digital video analysis or by breaking infrared beams in the mouse cage. It is based on the algorithm that any episode of continuous inactivity of > or =40 s is predicted to be sleep. The method gives excellent agreement in C57BL/6J male mice with simultaneous assessment of sleep by EEG/EMG recording. The average agreement over 8,640 10-s epochs in 24 h is 92% (n = 7 mice) with agreement in individual mice being 88-94%. Average EEG/EMG determined sleep per 2-h interval across the day was 59.4 min. The estimated mean difference (bias) per 2-h interval between inactivity-defined sleep and EEG/EMG-defined sleep was only 1.0 min (95% confidence interval for mean bias -0.06 to +2.6 min). The standard deviation of differences (precision) was 7.5 min per 2-h interval with 95% limits of agreement ranging from -13.7 to +15.7 min. Although bias significantly varied by time of day (P = 0.0007), the magnitude of time-of-day differences was not large (average bias during lights on and lights off was +5.0 and -3.0 min per 2-h interval, respectively). This method has applications in chemical mutagenesis and for studies of molecular changes in brain with sleep/wakefulness.

  2. High blood pressure and visual sensitivity

    Science.gov (United States)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  3. Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

    Science.gov (United States)

    Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

    2015-07-03

    The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Effect of continuous positive airway pressure treatment on short-term memory performance over 24 h of sustained wakefulness in patients with obstructive sleep apnea-hypopnea syndrome.

    Science.gov (United States)

    Grenèche, Jérôme; Krieger, Jean; Bertrand, Frédéric; Erhardt, Christine; Maumy, Myriam; Tassi, Patricia

    2013-10-01

    Few studies have examined the impact of continuous positive airway pressure (CPAP) therapy on short-term memory (STM) over sustained wakefulness in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). We have investigated if impaired STM can be reversed by CPAP treatment in a 24-h sustained wakefulness paradigm. Our follow-up study was conducted with repeated-memory tasks within 12 OSAHS patients and 10 healthy controls who underwent three 32-h sessions, one before CPAP (T0) and the second (T3) and the third (T6), after 3 and 6 months of treatment, respectively, for OSAHS patients. Each session included one night of sleep followed by 24h of sustained wakefulness, during which both groups performed STM tasks including both digit span (DS) and Sternberg tasks. Untreated OSAHS patients had no deficit in the forward DS task measuring immediate memory but were impaired in STM, especially working memory assessed by the complex Sternberg task and the backward DS. However, only performance in the latter was improved after 6 months of CPAP treatment. Because the high level of memory scanning required high speed in information processing, persistent impairment on the complex Sternberg task may be attributable to working memory slowing, possibly enhanced by sustained wakefulness. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  5. Sleep variability and fatigue in adolescents: Associations with school-related features.

    Science.gov (United States)

    Matos, M G; Gaspar, T; Tomé, G; Paiva, T

    2016-10-01

    This study aims to evaluate the influences of sleep duration and sleep variability (SleepV), upon adolescents' school-related situations. The Health Behaviour in School-Aged Children (HBSC) survey is based on a self-completed questionnaire. The participants were 3164 pupils (53.7% girls), attending the 8th and 10th grades, 14.9 years old, and were inquired about subjective sleep duration during the week and weekends, SleepV, fatigue, difficulties in sleep initiation, school achievement, feelings towards schools, pressure with school work and skipping classes. Multiple regression models used, as dependent variables: (a) school achievement, (b) disliking school, (c) pressure with school work and (d) skipping classes, using as independent variables, each of the remaining school-related variables, fatigue, total sleep duration and difficulties in sleep initiation. The average sleep duration in the week and during weekdays was lower than recommended for these age groups, and almost half of students had high SleepV between weekdays and weekends. A logistic model revealed that the absence of SleepV was associated with lower perception of school work pressure, less frequent skipping classes, more infrequent fatigue and more infrequent difficulties in sleep initiation. Poor sleep quality, SleepV and insufficient sleep duration affected negatively school-related variables. © 2015 International Union of Psychological Science.

  6. Food processing by high hydrostatic pressure.

    Science.gov (United States)

    Yamamoto, Kazutaka

    2017-04-01

    High hydrostatic pressure (HHP) process, as a nonthermal process, can be used to inactivate microbes while minimizing chemical reactions in food. In this regard, a HHP level of 100 MPa (986.9 atm/1019.7 kgf/cm 2 ) and more is applied to food. Conventional thermal process damages food components relating color, flavor, and nutrition via enhanced chemical reactions. However, HHP process minimizes the damages and inactivates microbes toward processing high quality safe foods. The first commercial HHP-processed foods were launched in 1990 as fruit products such as jams, and then some other products have been commercialized: retort rice products (enhanced water impregnation), cooked hams and sausages (shelf life extension), soy sauce with minimized salt (short-time fermentation owing to enhanced enzymatic reactions), and beverages (shelf life extension). The characteristics of HHP food processing are reviewed from viewpoints of nonthermal process, history, research and development, physical and biochemical changes, and processing equipment.

  7. Effects of continuous positive airway pressure on neurocognitive function in obstructive sleep apnea patients: The Apnea Positive Pressure Long-term Efficacy Study (APPLES).

    Science.gov (United States)

    Kushida, Clete A; Nichols, Deborah A; Holmes, Tyson H; Quan, Stuart F; Walsh, James K; Gottlieb, Daniel J; Simon, Richard D; Guilleminault, Christian; White, David P; Goodwin, James L; Schweitzer, Paula K; Leary, Eileen B; Hyde, Pamela R; Hirshkowitz, Max; Green, Sylvan; McEvoy, Linda K; Chan, Cynthia; Gevins, Alan; Kay, Gary G; Bloch, Daniel A; Crabtree, Tami; Dement, William C

    2012-12-01

    To determine the neurocognitive effects of continuous positive airway pressure (CPAP) therapy on patients with obstructive sleep apnea (OSA). The Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blind, 2-arm, sham-controlled, multicenter trial conducted at 5 U.S. university, hospital, or private practices. Of 1,516 participants enrolled, 1,105 were randomized, and 1,098 participants diagnosed with OSA contributed to the analysis of the primary outcome measures. Active or sham CPAP MEASUREMENTS: THREE NEUROCOGNITIVE VARIABLES, EACH REPRESENTING A NEUROCOGNITIVE DOMAIN: Pathfinder Number Test-Total Time (attention and psychomotor function [A/P]), Buschke Selective Reminding Test-Sum Recall (learning and memory [L/M]), and Sustained Working Memory Test-Overall Mid-Day Score (executive and frontal-lobe function [E/F]) The primary neurocognitive analyses showed a difference between groups for only the E/F variable at the 2 month CPAP visit, but no difference at the 6 month CPAP visit or for the A/P or L/M variables at either the 2 or 6 month visits. When stratified by measures of OSA severity (AHI or oxygen saturation parameters), the primary E/F variable and one secondary E/F neurocognitive variable revealed transient differences between study arms for those with the most severe OSA. Participants in the active CPAP group had a significantly greater ability to remain awake whether measured subjectively by the Epworth Sleepiness Scale or objectively by the maintenance of wakefulness test. CPAP treatment improved both subjectively and objectively measured sleepiness, especially in individuals with severe OSA (AHI > 30). CPAP use resulted in mild, transient improvement in the most sensitive measures of executive and frontal-lobe function for those with severe disease, which suggests the existence of a complex OSA-neurocognitive relationship. Registered at clinicaltrials.gov. Identifier: NCT00051363. Kushida CA; Nichols DA; Holmes

  8. Rheological assessment of nanofluids at high pressure high temperature

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza

    2013-11-01

    High pressure high temperature (HPHT) fluids are commonly encountered in industry, for example in cooling and/or lubrications applications. Nanofluids, engineered suspensions of nano-sized particles dispersed in a base fluid, have shown prospective as industrial cooling fluids due to their enhanced rheological and heat transfer properties. Nanofluids can be potentially utilized in oil industry for drilling fluids and for high pressure water jet cooling/lubrication in machining. In present work rheological characteristics of oil based nanofluids are investigated at HPHT condition. Nanofluids used in this study are prepared by dispersing commercially available SiO2 nanoparticles (~20 nm) in a mineral oil. The basefluid and nanofluids with two concentrations, namely 1%, and 2%, by volume, are considered in this investigation. The rheological characteristics of base fluid and the nanofluids are measured using an industrial HPHT viscometer. Viscosity values of the nanofluids are measured at pressures of 100 kPa to 42 MPa and temperatures ranging from 25°C to 140°C. The viscosity values of both nanofluids as well as basefluid are observed to have increased with the increase in pressure. Funded by Qatar National Research Fund (NPRP 08-574-2-239).

  9. EFFECT OF OBSTRUCTIVE SLEEP APNEA SYNDROME ON ARTERIAL STIFFNESS IN PATIENTS AT HIGH CARDIOVASCULAR RISK

    Directory of Open Access Journals (Sweden)

    V. E. Oleynikov

    2016-01-01

    Full Text Available Aim. To assess the impact of metabolic abnormalities in combination with obstructive sleep apnea on endothelial function and vascular stiffness parameters in patients with arterial hypertension 1-2 degrees. Material and methods. Patients (n=74 with metabolic syndrome and obstructive sleep apnea were included into the study. All patients underwent cardiorespiratory monitoring of sleep using SomnoCheck2 device (Wiennmann, Germany and were divided into two groups based on its results. Patients with apnea-hypopnea index (AHI <30 episodes per hour were included into group 1 and patients with AHI >30 episodes per hour – into group 2. Monitoring of ambulatory blood pressure (BP and arterial stiffness was performed by the device BPLab ("Peter Telegin", Russia. Endothelial function was assessed in a probe of flow-mediated dilation by the ultrasound device MyLab 90 (Esaote, Italy. Diameter of the common carotid artery (DCCA and the intima-media thickness (IMT were determined. Results. Patients with AHI >30 episodes per hour had higher mean daily and night systolic BP and pulse BP in aorta and brachial artery. Pulse wave velocity in aorta in per day averaged was also higher in these patients (8.2±0.8 vs 9.1±1.1 m/sec; p<0.05. Mean level of flow-mediated dilation was significantly lower in patients with severe sleep apnea> (8.8% (5.6; 13.1 vs 4.5% (2.2; 8.0; p<0.05. Prevalence of negative index of reactivity in group 2 was 2 times higher than this in group 1. An increase in IMT and DCCA in patients with severe obstructive sleep apnea was also revealed. Conclusion. Severe sleep apnea in patients with metabolic syndrome in combination with hypertension aggravates structural changes and endothelial dysfunction of the main arteries, as well as contributes to the progression of atherosclerosis.

  10. Continuous positive airway pressure reduces blood pressure in patients with obstructive sleep apnea; a systematic review and meta-analysis with 1000 patients.

    Science.gov (United States)

    Schein, Andressa S O; Kerkhoff, Alessandra C; Coronel, Christian C; Plentz, Rodrigo D M; Sbruzzi, Graciele

    2014-09-01

    Obstructive sleep apnea (OSA) may lead to the development of hypertension and therapy with continuous positive airway pressure (CPAP) can promote reduction in blood pressure. The objective of this study is to review systematically the effects of CPAP on blood pressure in patients with OSA. The search was conducted in the following databases, from their beginning until February 2013: MEDLINE, Embase, Cochrane CENTRAL, Lilacs and PEDro. In addition, a manual search was performed on references of published studies. Randomized clinical trials (RCTs) that used CPAP compared with placebo CPAP or subtherapeutic CPAP for treatment of patients with OSA and that evaluated office SBP and DBP and 24-h ambulatory blood pressure were selected. Sixteen RCTs were included among 3409 publications, totaling 1166 patients. The use of CPAP resulted in reductions in office SBP [-3.20  mmHg; 95% confidence interval (CI) -4.67 to -1.72] and DBP (-2.87  mmHg; 95% CI -5.18 to -0.55); in night-time SBP (-4.92  mmHg; 95% CI -8.70 to -1.14); in mean 24-h blood pressure (-3.56  mmHg; 95% CI -6.79 to -0.33), mean night-time blood pressure (-2.56  mmHg; 95% CI -4.43 to -0.68) and 24-h DBP (-3.46  mmHg; 95% CI -6.75 to -0.17). However, no significant change was observed in daytime SBP (-0.74  mmHg; 95% CI -3.90 to 2.41) and daytime DBP (-1.86  mmHg; 95% CI -4.55 to 0.83). Treatment with CPAP promoted significantly but small reductions in blood pressure in individuals with OSA. Further studies should be performed to evaluate the effects of long-term CPAP and the impact on cardiovascular risk.

  11. Engineering Model of High Pressure Moist Air

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš

    2017-01-01

    Full Text Available The article deals with the moist air equation of state. There are equations of state discussed in the article, i.e. the model of an ideal mixture of ideal gases, the model of an ideal mixture of real gases and the model based on the virial equation of state. The evaluation of sound speed based on the ideal mixture concept is mentioned. The sound speed calculated by the model of an ideal mixture of ideal gases is compared with the sound speed calculated by using the model based on the concept of an ideal mixture of real gases. The comparison of enthalpy end entropy based on the model of an ideal mixture of ideal gases and the model of an ideal mixture of real gases is performed. It is shown that the model of an ideal mixture of real gases deviates from the model of an ideal mixture of ideal gases only in the case of high pressure. An impossibility of the definition of partial pressure in the mixture of real gases is discussed, where the virial equation of state is used.

  12. [High blood pressure and physical exercise].

    Science.gov (United States)

    Sosner, P; Gremeaux, V; Bosquet, L; Herpin, D

    2014-06-01

    High blood pressure is a frequent pathology with many cardiovascular complications. As highlighted in guidelines, the therapeutic management of hypertension relies on non-pharmacological measures, which are diet and regular physical activity, but both patients and physicians are reluctant to physical activity prescription. To acquire the conviction that physical activity is beneficial, necessary and possible, we can take into account some fundamental and clinical studies, as well as the feedback of our clinical practice. Physical inactivity is a major risk factor for cardiovascular morbidity and mortality, and hypertension contributes to increase this risk. Conversely, regular practice of physical activity decreases very significantly the risk by up to 60%. The acute blood pressure changes during exercise and post-exercise hypotension differs according to the dynamic component (endurance or aerobic and/or strength exercises), but the repetition of the sessions leads to the chronic hypotensive benefit of physical activity. Moreover, physical activity prescription must take into account the assessment of global cardiovascular risk, the control of the hypertension, and the opportunities and desires of the patient in order to promote good adherence and beneficial lifestyle change. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. High incidence of sleep problems in children with developmental disorders: results of a questionnaire survey in a Japanese elementary school.

    Science.gov (United States)

    Matsuoka, Michiko; Nagamitsu, Shinichiro; Iwasaki, Mizue; Iemura, Akiko; Yamashita, Yushiro; Maeda, Masaharu; Kitani, Shingo; Kakuma, Tatsuyuki; Uchimura, Naohisa; Matsuishi, Toyojiro

    2014-01-01

    The aim of the present school-based questionnaire was to analyze the sleep problems of children with developmental disorders, such as pervasive developmental disorder and attention deficit hyperactivity disorder. The sleep problems of 43 children with developmental disorders were compared with those of 372 healthy children (control group). All children attended one public elementary school in Kurume, Japan; thus, the study avoided the potential bias associated with hospital-based surveys (i.e. a high prevalence of sleep disturbance) and provided a more complete picture of the children's academic performance and family situation compared with a control group under identical conditions. Children's sleep problems were measured with the Japanese version of the Children's Sleep Habits Questionnaire (CSHQ). Children with developmental disorders had significantly higher total CSHQ scores, as well as mean scores on the parasomnias and sleep breathing subscales, than children in the control group. The total CSHQ score, bedtime resistance, sleep onset delay, and daytime sleepiness worsened with increasing age in children with developmental disorders; in contrast, these parameters were unchanged or became better with age in the control group. In children with developmental disorders, there was a significant association between a higher total CSHQ score and lower academic performance, but no such association was found in the control group. For both groups, children's sleep problems affected their parents' quality of sleep. There were no significant differences in physical, lifestyle, and sleep environmental factors, or in sleep/wake patterns, between the two groups. Children with developmental disorders have poor sleep quality, which may affect academic performance. It is important for physicians to be aware of age-related differences in sleep problems in children with developmental disorders. Further studies are needed to identify the association between sleep quality and

  14. Development of Home-Based Sleep Monitoring System for Obstructive Sleep Apnea.

    Science.gov (United States)

    Wu, Peirong; Chen, Guan-Ting; Cui, Yanyan; Li, Jin-Wei; Kuo, Terry B J; Chang, Polun

    2017-01-01

    Obstructive Sleep Apnea (OSA) has been proven to increase the risk of high blood pressure, heart attack, stroke, obesity, and diabetes. If people would like to know whether they are suffering from this sleep disorder, they need to go to particular hospital with which a sleep center that could perform polysomnography (PSG); however, for most people, this is not convenient. Consequently, the goal of this study is to develop a convenient, lower priced, and easy-to-use home-based sleep monitoring system. The researchers have developed the "Sleep Healthcare Management System" for OSA patients and healthcare providers. It combines smartphone and wearable devices that can perform real-time sleep monitoring. Healthcare providers could apply their professional knowledge to provide customized feedback via a web application. When the patient is diagnosed with an abnormal sleep health condition, healthcare providers may be able to provide appropriate and timely care.

  15. High pressure fiber optic sensor system

    Science.gov (United States)

    Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

    2013-11-26

    The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

  16. Effect of low and high glycaemic index drink on sleep pattern in children

    International Nuclear Information System (INIS)

    Jalilolghadr, S.; Afaghi, A.; Connor, H.O.; Chow, C.M.

    2011-01-01

    Objectives: To evaluate the effect of high and low glycaemic index drinks on children's sleep pattern. Methods: Eight children underwent 3 nights of full polysomnography study, one familiarization and two test nights consecutively. On the test nights, 1 hour before bedtime, the children had a milk drink of either low or high GI in a random order. The glycaemic loads (GL) were 7.4 and 52.8 for low and high GI drink respectively. Results: The mean of total arousal index in the first half of night after the high GI was greater than that of low GI drink. (12.9 +- 4.6 vs. 9.9 +- 2.2, P=0.03). NREM arousal index in the first half of night after the high GI was also higher than that of low GI drink. (12.7+- 4.8 vs. 9.6 +- 2.3, P=0.05). Other sleep parameters did not show any significant difference in low GI and high GI diets. Conclusion: NREM and total arousal indices were higher in those who consumed high GI drinks compared with low GI, one hour before sleep. It seems that the high quantity consumption of carbohydrates close to the bedtime is accompanied by frequent arousals and may affect the sleep quality. (author)

  17. Computer simulations of high pressure systems

    International Nuclear Information System (INIS)

    Wilkins, M.L.

    1977-01-01

    Numerical methods are capable of solving very difficult problems in solid mechanics and gas dynamics. In the design of engineering structures, critical decisions are possible if the behavior of materials is correctly described in the calculation. Problems of current interest require accurate analysis of stress-strain fields that range from very small elastic displacement to very large plastic deformation. A finite difference program is described that solves problems over this range and in two and three space-dimensions and time. A series of experiments and calculations serve to establish confidence in the plasticity formulation. The program can be used to design high pressure systems where plastic flow occurs. The purpose is to identify material properties, strength and elongation, that meet the operating requirements. An objective is to be able to perform destructive testing on a computer rather than on the engineering structure. Examples of topical interest are given

  18. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  19. Recent developments in high pressure water technology

    International Nuclear Information System (INIS)

    Johnson, N.A.; Johnson, T.

    1992-01-01

    High Pressure Water Jetting has advanced rapidly in the last decade to a point where the field is splitting into specialised areas. This has left the end user or client in the dark as to whether water jetting will work and if so what equipment is best suited to their particular application. The aim of this paper is to give an overview of:-1. The way water is delivered to the surface and the parameters which control the concentration of energy available on impact. 2. The factors governing application driven selection of equipment. 3. The effects to technical advances in pumps and delivery systems on equipment selection with reference to their to their application to concrete removal and nuclear decontamination. (Author)

  20. Condensed matter at high shock pressures

    Energy Technology Data Exchange (ETDEWEB)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Radousky, H.B.; Hamilton, D.

    1985-07-12

    Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N/sub 2/, CO, SiO/sub 2/-aerogel, H/sub 2/O, and C/sub 6/H/sub 6/. The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab.

  1. High-pressure structures of methane hydrate

    International Nuclear Information System (INIS)

    Hirai, H; Uchihara, Y; Fujihisa, H; Sakashita, M; Katoh, E; Aoki, K; Yamamoto, Y; Nagashima, K; Yagi, T

    2002-01-01

    Three high-pressure structures of methane hydrate, a hexagonal structure (str. A) and two orthorhombic structures (str. B and str. C), were found by in situ x-ray diffractometry and Raman spectroscopy. The well-known structure I (str. I) decomposed into str. A and fluid at 0.8 GPa. Str. A transformed into str. B at 1.6 GPa, and str. B further transformed into str. C at 2.1 GPa which survived above 7.8 GPa. The fluid solidified as ice VI at 1.4 GPa, and the ice VI transformed to ice VII at 2.1 GPa. The bulk moduli, K 0 , for str. I, str. A, and str. C were calculated to be 7.4, 9.8, and 25.0 GPa, respectively

  2. High Pressure Quick Disconnect Particle Impact Tests

    Science.gov (United States)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact testing to determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). Testing included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This paper summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs. KEYWORDS: quick disconnect, high pressure, particle impact testing, stainless steel

  3. A Nutritional Strategy for the Treatment of High Blood Pressure.

    Science.gov (United States)

    Podell, Richard N.

    1984-01-01

    Some physicians wonder if high blood pressure can be controlled without the use of drugs and their potential side effects. Current findings concerning nutrition and high blood pressure are presented. (RM)

  4. Stress and High Blood Pressure: What's the Connection?

    Science.gov (United States)

    Stress and high blood pressure: What's the connection? Stress and long-term high blood pressure may not be linked, but taking steps to reduce your stress can improve your general health, including your blood ...

  5. High blood pressure - what to ask your doctor

    Science.gov (United States)

    What to ask your doctor about high blood pressure; Hypertension - what to ask your doctor ... problems? What medicines am I taking to treat high blood pressure? Do they have any side effects? What should ...

  6. High Blood Pressure, Afib and Your Risk of Stroke

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More High Blood Pressure, AFib and Your Risk of Stroke Updated:Aug ... have a stroke for the first time have high blood pressure . And an irregular atrial heart rhythm — a condition ...

  7. Corneal Neovascularization with Associated Lipid Keratopathy in a Patient with Obstructive Sleep Apnea-Hypopnea Syndrome Using a Continuous Positive Airway Pressure Machine

    Directory of Open Access Journals (Sweden)

    Konstantinos Oikonomakis

    2017-08-01

    Full Text Available Objective: To report a case of corneal neovascularization with secondary lipid keratopathy in a patient treated with continuous positive airway pressure (CPAP for obstructive sleep apnea-hypopnea syndrome (OSAHS. Case Report: A 49-year-old male had been diagnosed with obstructive sleep apnea syndrome 10 years ago and has been treated with the application of a CPAP machine during night sleep ever since. For the past year, the patient had been complaining for ocular irritation and excessive tearing of the left eye on awakening. Slit-lamp biomicroscopy revealed the presence of neovascularization and lipid exudation in the inferior third of the cornea of the left eye. Ocular patching during night sleep resulted in recession of the reported symptoms and shrinkage of the neovascularization, while the area of lipid exudation ceased to enlarge. Conclusion: To the best of our knowledge, this is the first report of corneal neovascularization in a patient using a CPAP machine for OSAHS.

  8. Corneal Neovascularization with Associated Lipid Keratopathy in a Patient with Obstructive Sleep Apnea-Hypopnea Syndrome Using a Continuous Positive Airway Pressure Machine.

    Science.gov (United States)

    Oikonomakis, Konstantinos; Petrelli, Myrsini; Andreanos, Konstantinos; Mouchtouris, Andreas; Petrou, Petros; Georgalas, Ilias; Papaconstantinou, Dimitrios; Kymionis, George

    2017-01-01

    To report a case of corneal neovascularization with secondary lipid keratopathy in a patient treated with continuous positive airway pressure (CPAP) for obstructive sleep apnea-hypopnea syndrome (OSAHS). A 49-year-old male had been diagnosed with obstructive sleep apnea syndrome 10 years ago and has been treated with the application of a CPAP machine during night sleep ever since. For the past year, the patient had been complaining for ocular irritation and excessive tearing of the left eye on awakening. Slit-lamp biomicroscopy revealed the presence of neovascularization and lipid exudation in the inferior third of the cornea of the left eye. Ocular patching during night sleep resulted in recession of the reported symptoms and shrinkage of the neovascularization, while the area of lipid exudation ceased to enlarge. To the best of our knowledge, this is the first report of corneal neovascularization in a patient using a CPAP machine for OSAHS.

  9. Adverse respiratory events after general anesthesia in patients at high risk of obstructive sleep apnea syndrome.

    Science.gov (United States)

    Xará, Daniela; Mendonça, Júlia; Pereira, Helder; Santos, Alice; Abelha, Fernando José

    2015-01-01

    Patients with STOP-BANG score >3 have a high risk of Obstructive sleep apnea. The aim of this study was to evaluate early postoperative respiratory complications in adults with STOP-BANG score >3 after general anesthesia. This is a prospective double cohort study matching 59 pairs of adult patients with STOP-BANG score >3 (high risk of obstructive sleep apnea) and patients with STOP-BANG score <3 (low risk of obstructive sleep apnea), similar with respect to gender, age and type of surgery, admitted after elective surgery in the Post-Anaesthesia Care Unit in May 2011. Primary outcome was the development of adverse respiratory events. Demographics data, perioperative variables, and postoperative length of stay in the Post-Anesthesia Care Unit and in hospital were recorded. The Mann-Whitney test, the chi-square test and the Fisher exact test were used for comparisons. Subjects in both pairs of study subjects had a median age of 56 years, including 25% males, and 59% were submitted to intra-abdominal surgery. High risk of obstructive sleep apnea patients had a higher median body mass index (31 versus 24kg/m(2), p<0.001) and had more frequently co-morbidities, including hypertension (58% versus 24%, p<0.001), dyslipidemia (46% versus 17%, p<0.001) and insulin-treated diabetes mellitus (17% versus 2%, p=0.004). These patients were submitted more frequently to bariatric surgery (20% versus 2%, p=0.002). Patients with high risk of obstructive sleep apnea had more frequently adverse respiratory events (39% versus 10%, p<0.001), mild to moderate desaturation (15% versus 0%, p=0.001) and inability to breathe deeply (34% versus 9%, p=0.001). After general anesthesia high risk of obstructive sleep apnea patients had an increased incidence of postoperative respiratory complications. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  10. [Adverse respiratory events after general anesthesia in patients at high risk of obstructive sleep apnea syndrome].

    Science.gov (United States)

    Xará, Daniela; Mendonça, Júlia; Pereira, Helder; Santos, Alice; Abelha, Fernando José

    2015-01-01

    Patients with STOP-BANG score >3 have a high risk of Obstructive sleep apnea. The aim of this study was to evaluate early postoperative respiratory complications in adults with STOP-BANG score >3 after general anesthesia. This is a prospective double cohort study matching 59 pairs of adult patients with STOP-BANG score >3 (high risk of obstructive sleep apnea) and patients with STOP-BANG score <3 (low risk of obstructive sleep apnea), similar with respect to gender, age and type of surgery, admitted after elective surgery in the Post-Anaesthesia Care Unit in May 2011. Primary outcome was the development of adverse respiratory events. Demographics data, perioperative variables, and postoperative length of stay in the Post-Anesthesia Care Unit and in hospital were recorded. The Mann-Whitney test, the chi-square test and the Fisher exact test were used for comparisons. Subjects in both pairs of study subjects had a median age of 56 years, including 25% males, and 59% were submitted to intra-abdominal surgery. High risk of obstructive sleep apnea patients had a higher median body mass index (31 versus 24kg/m(2), p<0.001) and had more frequently co-morbidities, including hypertension (58% versus 24%, p<0.001), dyslipidemia (46% versus 17%, p<0.001) and insulin-treated diabetes mellitus (17% versus 2%, p=0.004). These patients were submitted more frequently to bariatric surgery (20% versus 2%, p=0.002). Patients with high risk of obstructive sleep apnea had more frequently adverse respiratory events (39% versus 10%, p<0.001), mild to moderate desaturation (15% versus 0%, p=0.001) and inability to breathe deeply (34% versus 9%, p=0.001). After general anesthesia high risk of obstructive sleep apnea patients had an increased incidence of postoperative respiratory complications. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  11. Natural history of treatment-emergent central sleep apnea on positive airway pressure: A systematic review

    Directory of Open Access Journals (Sweden)

    Gaurav Nigam

    2018-01-01

    CONCLUSIONS: Overall, TECSA developed in 3.5%–19.8% of PAP-treated patients with OSA. The vast majority will experience complete resolution of central apneas over a few weeks to months. Unfortunately, about a third of patients with TECSA may continue to exhibit persistence of central sleep apnea on reevaluation. A small proportion may experience D-TECSA after few weeks to several months of initial exposure to PAP therapy.

  12. Long working hours and sleep problems among public junior high school teachers in Japan.

    Science.gov (United States)

    Bannai, Akira; Ukawa, Shigekazu; Tamakoshi, Akiko

    2015-01-01

    Long working hours may impact human health. In Japan, teachers tend to work long hours. From 2002 to 2012, the number of leaves of absence due to diseases other than mental disorders, or mental disorders among public school teachers increased by 1.3 times (from 2,616 to 3,381), or 1.8 times (from 2,687 to 4,960), respectively. The present study aimed to investigate the association between long working hours and sleep problems among public school teachers. This cross-sectional study was conducted from mid-July to September 2013 in Hokkaido Prefecture, Japan. Questionnaires were distributed to 1,245 teachers in public junior high schools. Information about basic characteristics including working hours, and responses to the Pittsburgh Sleep Quality Index were collected anonymously. Multiple logistic regression analysis was used to calculate odds ratios (ORs) for the association between long working hours and sleep problems separately by sex. The response rate was 44.8% (n=558). After excluding ineligible responses, the final sample comprised 515 teachers (335 males and 180 females). Sleep problems was identified in 41.5% of males and 44.4% of females. Our results showed a significantly increased risk of sleep problems in males working >60 hours per week (OR 2.05 [95% CI 1.01-4.30]) compared with those working ≤40 hours per week. No significant association was found in females. There is a significant association between long working hours and sleep problems in male teachers. Reducing working hours may contribute to a reduction in sleep problems.

  13. Effect of high pressure on mesophilic lactic fermentation streptococci

    Energy Technology Data Exchange (ETDEWEB)

    Reps, A; Kuzmicka, M; Wisniewska, K [Chair of Food Biotechnology, University of Warmia and Mazury, ul. Heweliusza 1, 10-724 Olsztyn (Poland)], E-mail: arnold.reps@uwm.edu.pl

    2008-07-15

    The research concerned the effect of high pressure on mesophilic lactic fermentation streptococci, present in two cheese-making commercial inocula produced by Christian-Hansen. Water solutions of inocula were pressurized at 50-800 MPa, at room temperature, for 30-120 min. Pressurization at 50-100 MPa slightly increased or reduced the number of lactic streptococci, depending on the inoculum and pressurization time. Pressurization at 200 MPa caused a reduction in the number of streptococci by over 99.9%, whereas the pressure of 400 MPa and above almost completely inactivated streptococci. Pressurization also reduced the dynamics of microorganism growth and acidification, to the degree depending on the pressure.

  14. [Associations of the work duration, sleep duration and number of holidays with an exaggerated blood pressure response during an exercise stress test among workers].

    Science.gov (United States)

    Michishita, Ryoma; Ohta, Masanori; Ikeda, Masaharu; Jiang, Ying; Yamato, Hiroshi

    2016-01-01

    It has been reported that an exaggerated systolic blood pressure (ESBP) response during exercise, even if resting blood pressure is normal, is associated with an increased risk of future hypertension and cardiovascular disease (CVD). This study was designed to investigate the relationships of work duration, sleep duration and number of holidays with blood pressure response during an exercise stress test among normotensive workers. The subjects were 362 normotensive workers (79 males and 283 females; age, 49.1 years). A multi-stage graded submaximal exercise stress test was performed on each subject using an electric bicycle ergometer. The workload was increased every 3 minutes, and blood pressure was measured at rest and during the last 1 minute of each stage. In this study, an ESBP response during exercise was defined according to the criteria of the Framingham Study (peak systolic blood pressure ≥210 mmHg in males, or ≥190 mmHg in females). Working environments, work duration, sleep duration, number of holidays, and physical activity during commuting and work, and leisure time exercise duration were evaluated using a questionnaire. An ESBP response during exercise was observed in 94 (26.0%) workers. The adjusted odds ratio for the prevalence of an ESBP response during exercise was found to be significantly higher with an increase in work duration, decreases in sleep duration and number of holidays (pwork duration with lowest sleep duration and number of holidays groups had significantly higher adjusted odds ratio for the prevalence of an ESBP response during exercise than the lowest work duration with highest sleep duration and number of holidays groups (pwork duration, short sleep duration and small number of holidays.

  15. Subnanosecond breakdown in high-pressure gases

    Science.gov (United States)

    Naidis, George V.; Tarasenko, Victor F.; Babaeva, Natalia Yu; Lomaev, Mikhail I.

    2018-01-01

    Pulsed discharges in high-pressure gases are of considerable interest as sources of nonequilibrium plasma for various technological applications: pollution control, pumping of laser media, plasma-assisted combustion, etc. Recently, attention has been attracted to the use of subnanosecond voltage fronts, producing diffuse discharges with radii of several millimeters. Such plasma structures, similar to pulsed glow discharges, are of special interest for applications due to quasi-uniformity of plasma parameters in relatively large gas volumes. This review presents the results of experimental and computational study of subnanosecond diffuse discharge formation. A description of generators of short high-voltage pulses with subnanosecond fronts and of discharge setups is given. Diagnostic methods for the measurement of various discharge parameters with high temporal and spatial resolution are described. Obtained experimental data on plasma properties for a wide range of governing factors are discussed. A review of various theoretical approaches used for computational study of the dynamics and structure of fast ionization waves is given; the applicability of conventional fluid streamer models for simulation of subnanosecond ionization waves is discussed. Calculated spatial-temporal profiles of plasma parameters during streamer propagation are presented. The efficiency of subnanosecond discharges for the production of reactive species is evaluated. On the basis of the comparison of simulation results and experimental data the effects of various factors (voltage rise time, polarity, etc.) on discharge characteristics are revealed. The major physical phenomena governing the properties of subnanosecond breakdown are analyzed.

  16. High pressure apparatus transport properties study in high magnetic field

    Czech Academy of Sciences Publication Activity Database

    Honda, F.; Sechovský, V.; Mikulina, O.; Kamarád, Jiří; Alsmadi, A. M.; Nakotte, H.; Lacerda, A. H.

    2002-01-01

    Roč. 16, 20, 21 & 22 (2002), s. 3330-3333 ISSN 0217-9792 R&D Projects: GA ČR GP202/01/D045; GA ČR GA202/00/1217; GA MŠk ME 165 Grant - others:NSF(XX) DMR-0094241 Institutional research plan: CEZ:AV0Z1010914 Keywords : high-pressure apparatus Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.604, year: 2002

  17. [Relationships between prevalence of youth risk behaviors and sleep duration among Japanese high school students].

    Science.gov (United States)

    Kataoka, Chie; Nozu, Yuji; Kudo, Masako; Sato, Yuki; Kubo, Motoyoshi; Nakayama, Naoko; Iwata, Hideki; Watanabe, Motoi

    2014-01-01

    This study aimed to clarify relationships between prevalence of risk behaviors and sleep duration among Japanese high school students. Data from a national survey, the Japan Youth Risk Behavior Survey 2011 (the subjects were 9,778 students: 5,027 males, 4,751 females, in the first grade to the third grade of 102 schools randomly selected among high schools throughout Japan) was used for this analysis. We focused on nine items of risk behavior in JYRBS: "lack of vigorous physical activity," "skipping breakfast," "current cigarette use," "current alcohol use," "lifetime thinner use," "ever had sexual intercourse," "rarely or never wore seatbelts," "in a physical fight," and "seriously considered attempting suicide." Students with less than six hours of sleep duration accounted for approximately 40% of males and females. The odds ratios of prevalence of each of the nine risk behaviors were calculated on the basis of the group "six hours or more and less than eight hours" of sleep, whose prevalence of risk behaviors was the lowest. In the group with "four hours or more and less than six hours," the odds ratios of "lack of vigorous physical activity" and "skipping breakfast" for both males and females were significantly high. Furthermore, in the group with shorter sleep duration of "less than four hours," the odds ratios of all nine risk behaviors for males (odds ratios: 1.47-3.28) and eight risk behaviors (except for "rarely or never wore seatbelts") for females (1.54-4.68) were significantly high. On the other hand, in the group with long sleep duration of "10 hours or more," the odds ratios of "current cigarette use" and "lifetime thinner use" for both males and females were significantly high. It was shown that short sleep duration of less than six hours and long sleep duration of 10 hours or more related to the prevalence of youth risk behaviors among Japanese high school students. It was suggested that sleep duration should be considered as an important category

  18. 30 CFR 56.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-pressure hose connections. 56.13021... and Boilers § 56.13021 High-pressure hose connections. Except where automatic shutoff valves are used, safety chains or other suitable locking devices shall be used at connections to machines of high-pressure...

  19. 76 FR 38697 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2011-07-01

    ... imports from China of high pressure steel cylinders, provided for in subheading 7311.00.00 of the... threatened with material injury by reason of LTFV and subsidized imports of high pressure steel cylinders... contained in USITC Publication 4241 (July 2011), entitled High Pressure Steel Cylinders from China...

  20. 77 FR 37712 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2012-06-22

    ...), that an industry in the United States is materially injured by reason of imports of high pressure steel... preliminary determinations by Commerce that imports of high pressure steel cylinders from China were... Publication 4328 (June 2012), entitled High Pressure Steel Cylinders from China: Investigation Nos. 701-TA-480...

  1. Restoring the salivary cortisol awakening response through nasal continuous positive airway pressure therapy in obstructive sleep apnea.

    Science.gov (United States)

    Ghiciuc, Cristina Mihaela; Dima Cozma, Lucia Corina; Bercea, Raluca Mihaela; Lupusoru, Catalina Elena; Mihaescu, Traian; Szalontay, Andreea; Gianfreda, Angela; Patacchioli, Francesca Romana

    2013-10-01

    Partial and largely conflicting data are currently available on the interplay between obstructive sleep apnea (OSA) and hypothalamus-pituitary-adrenal axis (HPA) activity in adult obese men. This study was performed to evaluate the daily trajectories of salivary cortisol, specifically with respect to the salivary cortisol awakening response (CAR), a common method used to assess HPA axis activity. The main findings of this study were that adult male obese subjects who were newly diagnosed with severe OSA showed the following: (1) a flattening of the CAR; (2) levels of cortisol at awakening that were lower than those of the controls; and (3) maintenance of the physiological circadian activity of the HPA axis, with the highest hormone concentrations produced in the morning and the lowest in the evening. This study was also designed to investigate the effects of 3 and 6 mos of treatment with continuous airways positive pressure (CPAP). CPAP use resulted in a significant recovery of the sleep patterns disrupted by OSA; moreover, mild neuropsychological signs of depression and anxiety in severe OSA patients were concomitantly progressively improved by CPAP treatment. Furthermore, this study reports that 3 and 6 mos of CPAP therapy restored the presence of CAR and was able to significantly reduce the difference in the morning cortisol levels between the OSA and control groups. In conclusion, we report here that compared with obese nonapneic matched controls, OSA patients present a dysregulation of HPA axis activity, as shown by the flattening of the diurnal pattern of cortisol production in response to repeated challenge due to hypoxia and sleep fragmentation. This dysregulation was especially detectable in the first hour after awakening and restored after 3 and 6 mos of treatment with CPAP.

  2. Effect of CPAP on blood pressure in patients with obstructive sleep apnea and resistant hypertension: the HIPARCO randomized clinical trial.

    Science.gov (United States)

    Martínez-García, Miguel-Angel; Capote, Francisco; Campos-Rodríguez, Francisco; Lloberes, Patricia; Díaz de Atauri, María Josefa; Somoza, María; Masa, Juan F; González, Mónica; Sacristán, Lirios; Barbé, Ferrán; Durán-Cantolla, Joaquín; Aizpuru, Felipe; Mañas, Eva; Barreiro, Bienvenido; Mosteiro, Mar; Cebrián, Juan J; de la Peña, Mónica; García-Río, Francisco; Maimó, Andrés; Zapater, Jordi; Hernández, Concepción; Grau SanMarti, Nuria; Montserrat, Josep María

    2013-12-11

    More than 70% of patients with resistant hypertension have obstructive sleep apnea (OSA). However, there is little evidence about the effect of continuous positive airway pressure (CPAP) treatment on blood pressure in patients with resistant hypertension. To assess the effect of CPAP treatment on blood pressure values and nocturnal blood pressure patterns in patients with resistant hypertension and OSA. Open-label, randomized, multicenter clinical trial of parallel groups with blinded end point design conducted in 24 teaching hospitals in Spain involving 194 patients with resistant hypertension and an apnea-hypopnea index (AHI) of 15 or higher. Data were collected from June 2009 to October 2011. CPAP or no therapy while maintaining usual blood pressure control medication. The primary end point was the change in 24-hour mean blood pressure after 12 weeks. Secondary end points included changes in other blood pressure values and changes in nocturnal blood pressure patterns. Both intention-to-treat (ITT) and per-protocol analyses were performed. A total of 194 patients were randomly assigned to receive CPAP (n = 98) or no CPAP (control; n = 96). The mean AHI was 40.4 (SD, 18.9) and an average of 3.8 antihypertensive drugs were taken per patient. Baseline 24-hour mean blood pressure was 103.4 mm Hg; systolic blood pressure (SBP), 144.2 mm Hg; and diastolic blood pressure (DBP), 83 mm Hg. At baseline, 25.8% of patients displayed a dipper pattern (a decrease of at least 10% in the average nighttime blood pressure compared with the average daytime blood pressure). The percentage of patients using CPAP for 4 or more hours per day was 72.4%. When the changes in blood pressure over the study period were compared between groups by ITT, the CPAP group achieved a greater decrease in 24-hour mean blood pressure (3.1 mm Hg [95% CI, 0.6 to 5.6]; P = .02) and 24-hour DBP (3.2 mm Hg [95% CI, 1.0 to 5.4]; P = .005), but not in 24-hour SBP (3.1 mm Hg [95% CI, -0.6 to 6

  3. Obstructive sleep apnea syndrome and sleep quality in hypertensive patients.

    Science.gov (United States)

    Bacci, Marcelo Rodrigues; Emboz, Jonathan Naim Mora; Alves, Beatriz da Costa Aguiar; Veiga, Glaucia Luciano da; Murad, Neif; Meneghini, Adriano; Chagas, Antonio Carlos P; Fonseca, Fernando Luiz Affonso

    2017-12-01

    Obstructive sleep apnea and hypopnea syndrome (OSAHS) is one of the developmental factors of high blood pressure (HBP), a relevant global public health problem. OSAHS is characterized by the reduction or complete cessation of respiratory airflow due to intermittent airway collapse. Additionally, significant changes in sleep rhythm and pattern are observed in these patients. To evaluate the association between OSAHS and sleep quality in essential and resistant hypertensives. A cross-sectional, observational study evaluated 43 hypertensive patients treated at the outpatient clinics of the Faculdade de Medicina do ABC (FMABC) who were medicated with two or more antihypertensive drugs and divided into nonresistant or resistant to treatment. Group I (using up to two antihypertensive agents - 60.47% of the sample) presented mean systolic blood pressure (SBP) of 127.5±6.4 mmHg, mean diastolic blood pressure (DBP) of 79.6±5.2 mmHg, mean body mass index (BMI) of 27.2±5.3 kg/m2 and mean age of 51.2±15.1 years. Group II (using more than two antihypertensive drugs - 37.2% of the sample) presented mean SBP of 132.1±9.3 mmHg, mean DBP of 84.5±5.8 mmHg, mean BMI of 27.2±7.2 kg/m2 and mean age of 55.5±13.4 years. The patients presented low quality of sleep/sleep disorder evaluated by the Pittsburgh Sleep Quality Index (PSQI), which represents a preponderant factor for OSAHS. Patients at high risk for OSAHS had poor sleep quality and high levels of DBP, suggesting a causal relation between these parameters. However, they did not present a higher prevalence of resistant high blood pressure (RHBP).

  4. Complex sleep apnea syndrome

    Directory of Open Access Journals (Sweden)

    Wang J

    2013-07-01

    Full Text Available Juan Wang,1,* Yan Wang,1,* Jing Feng,1,2 Bao-yuan Chen,1 Jie Cao1 1Respiratory Department of Tianjin Medical University General Hospital, Tianjin, People's Republic of China; 2Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, NC, USA *The first two authors contributed equally to this work Abstract: Complex sleep apnea syndrome (CompSAS is a distinct form of sleep-disordered breathing characterized as central sleep apnea (CSA, and presents in obstructive sleep apnea (OSA patients during initial treatment with a continuous positive airway pressure (CPAP device. The mechanisms of why CompSAS occurs are not well understood, though we have a high loop gain theory that may help to explain it. It is still controversial regarding the prevalence and the clinical significance of CompSAS. Patients with CompSAS have clinical features similar to OSA, but they do exhibit breathing patterns like CSA. In most CompSAS cases, CSA events during initial CPAP titration are transient and they may disappear after continued CPAP use for 4–8 weeks or even longer. However, the poor initial experience of CompSAS patients with CPAP may not be avoided, and nonadherence with continued therapy may often result. Treatment options like adaptive servo-ventilation are available now that may rapidly resolve the disorder and relieve the symptoms of this disease with the potential of increasing early adherence to therapy. But these approaches are associated with more expensive and complicated devices. In this review, the definition, potential plausible mechanisms, clinical characteristics, and treatment approaches of CompSAS will be summarized. Keywords: complex sleep apnea syndrome, obstructive sleep apnea, central sleep apnea, apnea threshold, continuous positive airway pressure, adaptive servo-ventilation

  5. Association of Sleep Groups and Sleep Survey Results of High School Students

    Science.gov (United States)

    Anderson, Stephen A.; MacDonald, Lawrence; Frost, Frederica C.

    2006-01-01

    In January 2003 the High School Late Start Committee of the Northville Public Schools sent surveys to all families, faculty, and middle and high school students. The descriptive results of this survey can be found at www.northville.k12.mi.us/hr/late_start_committee_surveysummary.htm. This study focuses on the responses of the high school students,…

  6. The Impact of Altitude on Sleep-Disordered Breathing in Children Dwelling at High Altitude: A Crossover Study.

    Science.gov (United States)

    Hughes, Benjamin H; Brinton, John T; Ingram, David G; Halbower, Ann C

    2017-09-01

    Sleep-disordered breathing (SDB) is prevalent among children and is associated with adverse health outcomes. Worldwide, approximately 250 million individuals reside at altitudes higher than 2000 meters above sea level (masl). The effect of chronic high-altitude exposure on children with SDB is unknown. This study aims to determine the impact of altitude on sleep study outcomes in children with SDB dwelling at high altitude. A single-center crossover study was performed to compare results of high-altitude home polysomnography (H-PSG) with lower altitude laboratory polysomnography (L-PSG) in school-age children dwelling at high altitude with symptoms consistent with SDB. The primary outcome was apnea-hypopnea index (AHI), with secondary outcomes including obstructive AHI; central AHI; and measures of oxygenation, sleep quality, and pulse rate. Twelve participants were enrolled, with 10 included in the final analysis. Median altitude was 1644 masl on L-PSG and 2531 masl on H-PSG. Median AHI was 2.40 on L-PSG and 10.95 on H-PSG. Both obstructive and central respiratory events accounted for the difference in AHI. Oxygenation and sleep fragmentation were worse and pulse rate higher on H-PSG compared to L-PSG. These findings reveal a clinically substantial impact of altitude on respiratory, sleep, and cardiovascular outcomes in children with SDB who dwell at high altitude. Within this population, L-PSG underestimates obstructive sleep apnea and central sleep apnea compared to H-PSG. Given the shortage of high-altitude pediatric sleep laboratories, these results suggest a role for home sleep apnea testing for children residing at high altitude. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  7. Sleep habits, excessive daytime sleepiness and school performance in high school students.

    Science.gov (United States)

    Shin, Chol; Kim, Jinkwan; Lee, Sangduck; Ahn, Yongkyu; Joo, Soonjae

    2003-08-01

    A questionnaire survey was carried out to examine the sleep habits and excessive daytime sleepiness (EDS) of 3871 high school students with a mean age of 16.8 years in Korea. The results showed that mean total sleep time was 6.3 h/day for male students and 6.5 h/day for female students, which may be insufficient for adolescence during puberty. The overall prevalence of EDS (defined as an Epworth sleepiness scale score of >10) was 15.9% (14.9% for boys and 18.2% for girls). The prevalence of EDS increased significantly (P performance.

  8. Sleep education improves the sleep duration of adolescents: a randomized controlled pilot study.

    Science.gov (United States)

    Kira, Geoff; Maddison, Ralph; Hull, Michelle; Blunden, Sarah; Olds, Timothy

    2014-07-15

    To determine the feasibility and pilot a sleep education program in New Zealand high school students. A parallel, two-arm randomized controlled pilot trial was conducted. High school students (13 to 16 years) were randomly allocated to either a classroom-based sleep education program intervention (n = 15) or to a usual curriculum control group (n = 14). The sleep education program involved four 50-minute classroom-based education sessions with interactive groups. Students completed a 7-day sleep diary, a sleep questionnaire (including sleep hygiene, knowledge and problems) at baseline, post-intervention (4 weeks) and 10 weeks follow-up. An overall treatment effect was observed for weekend sleep duration (F 1,24 = 5.21, p = 0.03). Participants in the intervention group slept longer during weekend nights at 5 weeks (1:37 h:min, p = 0.01) and 10 weeks: (1:32 h:min, p = 0.03) compared to those in the control group. No differences were found between groups for sleep duration on weekday nights. No significant differences were observed between groups for any of the secondary outcomes (sleep hygiene, sleep problems, or sleep knowledge). A sleep education program appears to increase weekend sleep duration in the short term. Although this program was feasible, most schools are under time and resource pressure, thus alternative methods of delivery should be assessed for feasibility and efficacy. Larger trials of longer duration are needed to confirm these findings and determine the sustained effect of sleep education on sleep behavior and its impact on health and psychosocial outcomes. A commentary on this article appears in this issue on page 793.

  9. Prevalence, sleep characteristics, and comorbidities in a population at high risk for obstructive sleep apnea: A nationwide questionnaire study in South Korea.

    Directory of Open Access Journals (Sweden)

    Jun-Sang Sunwoo

    Full Text Available To determine the prevalence, sleep characteristics, and comorbidities associated with a high risk for obstructive sleep apnea (OSA in the Korean adult population.We analyzed data from 2,740 subjects who responded to a nationwide questionnaire survey of sleep characteristics. Those who qualified under two or more symptom categories of the Berlin questionnaire were defined as "at high risk for OSA". We investigated their socio-demographic information, sleep habits, and medical and psychiatric comorbidities. Logistic regression analyses were performed to identify factors and consequences significantly associated with a high risk for OSA.The prevalence of a high risk for OSA was 15.8% (95% confidence interval [CI] 14.5-17.2%. Multiple logistic regression analysis showed that old age (≥ 70 years, odds ratio [OR] 2.68 and body mass index ≥ 25 kg/m2 (OR 10.75 were significantly related with a high risk for OSA, whereas regular physical activity (OR 0.70 had a protective effect. Subjective sleep characteristics associated with a high risk for OSA were perceived insufficient sleep (OR 1.49, excessive daytime sleepiness (OR 1.88, and insomnia (OR 3.70. In addition, hypertension (OR 5.83, diabetes mellitus (OR 2.54, hyperlipidemia (OR 2.85, and anxiety (OR 1.63 were comorbid conditions independently associated with a high risk for OSA.This is the first study to demonstrate the prevalence of a high risk for OSA in a nationwide representative sample of the Korean adult population. These findings elucidate the epidemiology and clinical characteristics of those at high risk for OSA.

  10. Sleep and sleepiness among working and non-working high school evening students.

    Science.gov (United States)

    Teixeira, Liliane Reis; Lowden, Arne; Turte, Samantha Lemos; Nagai, Roberta; Moreno, Claudia Roberta de Castro; Latorre, Maria do Rosário Dias de Oliveira; Fischer, Frida Marina

    2007-01-01

    The aim of this study was to evaluate patterns of sleepiness, comparing working and non-working students. The study was conducted on high school students attending evening classes (19:00-22:30 h) at a public school in São Paulo, Brazil. The study group consisted of working (n=51) and non-working (n=41) students, aged 14-21 yrs. The students answered a questionnaire about working and living conditions and reported health symptoms and diseases. For seven consecutive days, actigraphy measurements were recorded, and the students also filled in a sleep diary. Sleepiness ratings were given six times per day, including upon waking and at bedtime, using the Karolinska Sleepiness Scale. Statistical analyses included three-way ANOVA and t-test. The mean sleep duration during weekdays was shorter among workers (7.2 h) than non-workers (8.8 h) (t=4.34; pSleep efficiency was lower on Fridays among non-workers. Working students were moderately sleepier than non-workers during the week and also during class on specific days: Mondays (13:00-15:00 h), Wednesdays (19:00-22:00 h), and Fridays (22:00-00:59 h). The study found that daytime sleepiness of workers is moderately higher in the evening. This might be due to a work effect, reducing the available time for sleep and shortening the sleep duration. Sleepiness and shorter sleep duration can have a negative impact on the quality of life and school development of high school students.

  11. Effects of positive airway pressure therapy on cardiovascular and metabolic markers in males with obstructive sleep apnea

    Directory of Open Access Journals (Sweden)

    A. Feliciano

    2017-07-01

    Full Text Available Introduction: Obstructive sleep apnea syndrome (OSAS is associated with cardiovascular/metabolic complications. Some analytical parameters (homocysteine, glycemic and lipidic profiles are recognized markers of these consequences. Limited data is available on the association of these markers and OSAS's severity/response to positive airway pressure therapy (PAP. Material and methods: In this prospective study we analyzed polysomnographic and analytical data of male patients admitted to sleep laboratory. The aim was to evaluate metabolic/cardiovascular markers in snorers and OSAS patients, to relate with sleep parameters and PAP response. One-hundred and three patients were included, and 73 (71% were OSAS patients. OSAS patients were similar to snorers except for higher body mass index (BMI and dyslipidemia. Severe OSAS patients showed higher glycemia, HbA1c, insulin, and insulin resistance, and lower HDL cholesterol in comparison to mild–moderate (p < 0.05, p < 0.05, p < 0.001, p < 0.001, p < 0.05, respectively. Glycemic profile and triglycerides were slightly correlated with OSAS severity. 46 OSAS patients were submitted to 6 months of PAP, with a statistical decrease in mean values of homocysteine, glycemia, total and LDL cholesterol (p < 0.05, p < 0.05, p < 0.05, respectively, and in glycemia and LDL cholesterol in severe group only (p < 0.05, p < 0.05, respectively. Results: This study demonstrated an association between glucose metabolism parameters and triglycerides with OSAS severity underlying the complexity of the process leading to cardiovascular/metabolic complications in this disorder. Moreover, homocysteine, glycemic and lipidic profiles changed significantly after 6 months of PAP therapy in OSAS, supporting its cardiovascular and metabolic protective effect. Conclusion: Our study has reinforced the importance of analytical cardiovascular/metabolic evaluation as

  12. Erectile Dysfunction and Sexual Hormone Levels in Men With Obstructive Sleep Apnea: Efficacy of Continuous Positive Airway Pressure.

    Science.gov (United States)

    Zhang, Xiao-Bin; Lin, Qi-Chang; Zeng, Hui-Qing; Jiang, Xing-Tang; Chen, Bo; Chen, Xiao

    2016-01-01

    In this study, the prevalence of erectile dysfunction (ED) and serum sexual hormone levels were evaluated in men with obstructive sleep apnea (OSA). In these patients, the efficacy of continuous positive airway pressure (CPAP) was determined. The 207 men (mean age 44.0 ± 11.1 years) enrolled in the study were stratified within four groups based on their apnea-hypopnea index score: simple snoring (n = 32), mild OSA (n = 29), moderate OSA (n = 38), and severe OSA (n = 108). The International Index of Erectile Dysfunction-5 (IIEF-5) score was obtained from each patient, and blood samples for the analysis of sexual hormones (prolactin, luteotropin, follicle-stimulating hormone, estradiol, progestin, and testosterone) were drawn in the morning after polysomnography. The IIEF-5 test and serum sexual hormone measurements were repeated after 3 months of CPAP treatment in 53 men with severe OSA. The prevalence of ED was 60.6 % in OSA patients overall and 72.2 % in those with severe OSA. Compared with the simple snoring group, patients with severe OSA had significantly lower testosterone levels (14.06 ± 5.62 vs. 17.02 ± 4.68, p = .018) and lower IIEF-5 scores (16.33 ± 6.50 vs. 24.09 ± 1.94, p = .001). The differences in the other sexual hormones between groups were not significant. After 3 months of CPAP treatment, there were no significant changes in sexual hormone levels, but the IIEF-5 score had improved significantly (18.21 ± 4.05 vs. 19.21 ± 3.86, p = .001). Severe OSA patients have low testosterone concentration and high ED prevalence. IIEF-5 scores increased significantly after CPAP treatment, but there was no effect on serum testosterone levels.

  13. Single stage high pressure centrifugal slurry pump

    Science.gov (United States)

    Meyer, John W.; Bonin, John H.; Daniel, Arnold D.

    1984-03-27

    Apparatus is shown for feeding a slurry to a pressurized housing. An impeller that includes radial passages is mounted in the loose fitting housing. The impeller hub is connected to a drive means and a slurry supply means which extends through the housing. Pressured gas is fed into the housing for substantially enveloping the impeller in a bubble of gas.

  14. Recombination times in germanium under high pressure

    International Nuclear Information System (INIS)

    Kuyt, J.H.

    1975-01-01

    The influence of pressure on a well defined recombination process was studied. The centres were introduced by γirradiation and the lifetime determined by the decay time of photoconductivity. An optical pressure vessel is described which allows for a hydrostatic variation of 3000 bars. The diffusion constant and lifetime measurements are presented and analysed. (V.J.C.)

  15. Cardiovascular reactivity to acute psychological stress following sleep deprivation.

    Science.gov (United States)

    Franzen, Peter L; Gianaros, Peter J; Marsland, Anna L; Hall, Martica H; Siegle, Greg J; Dahl, Ronald E; Buysse, Daniel J

    2011-10-01

    Psychological stress and sleep disturbances are highly prevalent and are both implicated in the etiology of cardiovascular diseases. Given the common co-occurrence of psychological distress and sleep disturbances including short sleep duration, this study examined the combined effects of these two factors on blood pressure reactivity to immediate mental challenge tasks after well-rested and sleep-deprived experimental conditions. Participants (n = 20) were healthy young adults free from current or past sleep, psychiatric, or major medical disorders. Using a within-subjects crossover design, we examined acute stress reactivity under two experimental conditions: after a night of normal sleep in the laboratory and after a night of total sleep deprivation. Two standardized psychological stress tasks were administered, a Stroop color-word naming interference task and a speech task, which were preceded by a prestress baseline period and followed by a poststress recovery period. Each period was 10 minutes in duration, and blood pressure recordings were collected every 2.5 minutes throughout each period. Mean blood pressure responses during stress and recovery periods were examined with a mixed-effects analysis of covariance, controlling for baseline blood pressure. There was a significant interaction between sleep deprivation and stress on systolic blood pressure (F(2,82.7) = 4.05, p = .02). Systolic blood pressure was higher in the sleep deprivation condition compared with the normal sleep condition during the speech task and during the two baseline periods. Sleep deprivation amplified systolic blood pressure increases to psychological stress. Sleep loss may increase cardiovascular risk by dysregulating stress physiology.

  16. Analysis of the effects of non-supine sleeping positions on the stress, strain, deformation and intraocular pressure of the human eye

    Science.gov (United States)

    Volpe, Peter A.

    This thesis presents analytical models, finite element models and experimental data to investigate the response of the human eye to loads that can be experienced when in a non-supine sleeping position. The hypothesis being investigated is that non-supine sleeping positions can lead to stress, strain and deformation of the eye as well as changes in intraocular pressure (IOP) that may exacerbate vision loss in individuals who have glaucoma. To investigate the quasi-static changes in stress and internal pressure, a Fluid-Structure Interaction simulation was performed on an axisymmetrical model of an eye. Common Aerospace Engineering methods for analyzing pressure vessels and hyperelastic structural walls are applied to developing a suitable model. The quasi-static pressure increase was used in an iterative code to analyze changes in IOP over time.

  17. Homeostasis in Primates in the Hyperdynamic Environment. [circadian timekeeping and effects of lower body positive pressure on sleep

    Science.gov (United States)

    Fuller, C. A.

    1985-01-01

    The influence of chronic centrifugation upon the homestatic regulation of the circadian timekeeping system was examined. The interactions of body temperature regulation and the behavioral state of arousal were studied by evaluating the influence of cephalic fluid shifts induced by lower body positive air pressure (LBPP), upon these systems. The small diurnal squirrel monkey (Saimiri sciureus) was used as the non-human primate model. Results show that the circadian timekeeping system of these primates is functional in the hyperdynamic environment, however, some of its components appear to be regulated at different homeostatic levels. The LBPP resulted in an approximate 0.7 C decrease in DBT (p 0.01). However, although on video some animals appeared drowsy during LBPP, sleep recording revealed no significant changes in state of arousal. Thus, the physiological mechanisms underlying this lowering of body temperature can be independent of the arousal state.

  18. Effect of continuous positive airway pressure ventilation on prethrombotic state in patients with obstructive sleep apnea-hypopnea syndrome

    International Nuclear Information System (INIS)

    Guo Dianbao; Chen Xiangkun; Sheng Chunyong; Zhang Yingying

    2009-01-01

    To investigate the prethrombotic state (PTS) in patients with obstructive sleep apnea syndrome (OS-AS) and the effect of continuous positive airway pressure ventilation (CPAP) on their PTS, the blood samples of 49 patients with OSAS were taken before treatment and on day 30 after treatment respectively. The platelet aggregation ( PAG), P-selections, endothdlin-1 (ET-1) and plasma vom willebrand factor (vWF) in 49 patients and 42 health controls were detected by radioimmunoassay and enzyme-immunoassay. The results showed that the PAG, P-selections, ET-1 and vWF in patients with OSAS before treatment were significantly higher than those after treatment and in control group (P 0.05). The results indicate that there were PTS in most patients with OSAS before treatment. The activity of platelet could be corrected, and the function of endotheliocyte could be repaired after CPAP treatment. It had certain effect in lightening the clinical symptoms. (authors)

  19. Sexual function and obstructive sleep apnea-hypopnea : A randomized clinical trial evaluating the effects of oral-appliance and continuous positive airway pressure therapy

    NARCIS (Netherlands)

    Hoekema, Aarnoud; Stel, Anna-Lucia; Stegenga, Boudewijn; van der Hoeven, Johannes H.; Wijkstra, Peter J.; van Driel, Mels F.; de Bont, Lambert G. M.

    Introduction. The obstructive sleep apnea-hypopnea syndrome (OSAHS) is associated with sexual dysfunction. Although successful treatment with continuous positive airway pressure (CPAP) has been demonstrated to improve sexual function, the effects of oral-appliance therapy are unknown. Aim. The aims

  20. All-cause mortality from obstructive sleep apnea in male and female patients with and without continuous positive airway pressure treatment

    DEFF Research Database (Denmark)

    Jennum, Poul; Tønnesen, Philip; Ibsen, Rikke

    2015-01-01

    BACKGROUND: More information is needed about the effect on mortality of continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea (OSA), especially in women. METHODS: We employed a historical cohort study design, using data from 25,389 patients with a diagnosis of OSA...

  1. Effects of Continuous Positive Airway Pressure on Cognitive and Functional Outcome of Stroke Patients with Obstructive Sleep Apnea: A Randomized Controlled Trial

    NARCIS (Netherlands)

    Aaronson, Justine A.; Hofman, Winni F.; van Bennekom, Coen A. M.; van Bezeij, Tijs; van den Aardweg, Joost G.; Groet, Erny; Kylstra, Wytske A.; Schmand, Ben

    2016-01-01

    Obstructive sleep apnea (OSA) in stroke patients is associated with worse functional and cognitive status during inpatient rehabilitation. We hypothesized that a four-week period of continuous positive airway pressure (CPAP) treatment would improve cognitive and functional outcomes. We performed a

  2. High Pressure Laminates with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Sandra Magina

    2016-02-01

    Full Text Available High-pressure laminates (HPLs are durable, resistant to environmental effects and good cost-benefit decorative surface composite materials with special properties tailored to meet market demand. In the present work, polyhexamethylene biguanide (PHMB was incorporated for the first time into melamine-formaldehyde resin (MF matrix on the outer layer of HPLs to provide them antimicrobial properties. Chemical binding of PHMB to resin matrix was detected on the surface of produced HPLs by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR. Antimicrobial evaluation tests were carried out on the ensuing HPLs doped with PHMB against gram-positive Listeria innocua and gram-negative Escherichia coli bacteria. The results revealed that laminates prepared with 1.0 wt % PHMB in MF resin were bacteriostatic (i.e., inhibited the growth of microorganisms, whereas those prepared with 2.4 wt % PHMB in MF resin exhibited bactericidal activity (i.e., inactivated the inoculated microorganisms. The results herein reported disclose a promising strategy for the production of HPLs with antimicrobial activity without affecting basic intrinsic quality parameters of composite material.

  3. Automated high pressure cell for pressure jump x-ray diffraction.

    Science.gov (United States)

    Brooks, Nicholas J; Gauthe, Beatrice L L E; Terrill, Nick J; Rogers, Sarah E; Templer, Richard H; Ces, Oscar; Seddon, John M

    2010-06-01

    A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

  4. Automated high pressure cell for pressure jump x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M. [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Terrill, Nick J. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Rogers, Sarah E. [ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2010-06-15

    A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

  5. Automated high pressure cell for pressure jump x-ray diffraction

    International Nuclear Information System (INIS)

    Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M.; Terrill, Nick J.; Rogers, Sarah E.

    2010-01-01

    A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

  6. Activity, sleep and ambient light have a different impact on circadian blood pressure, heart rate and body temperature rhythms.

    Science.gov (United States)

    Gubin, D G; Weinert, D; Rybina, S V; Danilova, L A; Solovieva, S V; Durov, A M; Prokopiev, N Y; Ushakov, P A

    2017-01-01

    The aim of the present study was to investigate the impact of endogenous and exogenous factors for the expression of the daily rhythms of body temperature (BT), blood pressure (BP) and heart rate (HR). One hundred and seventy-three young adults (YA), 17-24 years old (y.o.), of both genders were studied under a modified constant-routine (CR) protocol for 26 h. Participants were assigned randomly to groups with different lighting regimens: CR-LD, n = 77, lights (>400 l×) on from 09:00 to 17:00 h and off (lights on (>400 l×) during the whole experimental session; CR-DD, n = 15, constant dim light (Blood Pressure Monitoring (ABPM) records from 27 YA (16-38 y.o.) and BT self-measurement data from 70 YA (17-30 y.o.) taken on ≥ 3 successive days at 08:00, 11:00, 14:00, 17:00, 20:00, 23:00 and 03:00 were available. The obtained daily patterns were different between Control and CR-DD groups, due to effects of activity, sleep and light. The comparison of Control and CR-LD groups allowed the effects of sleep and activity to be estimated since the lighting conditions were similar. The activity level substantially elevated SBP, but not DBP. Sleep, on the other hand, lowered the nighttime DBP, but has no effect on SBP. HR was affected both by activity and sleep. In accordance with previous studies, these results confirm that the steep BP increase in the morning is not driven by the circadian clock, but rather by sympathoadrenal factors related to awakening and corresponding anticipatory mechanisms. The effect on BT was not significant. To investigate the impact of light during the former dark time and darkness during the former light time, the CR-LL and CR-DD groups were each compared with the CR-LD group. Light delayed the evening decrease of BT, most likely via a suppression of the melatonin rise. Besides, it had a prominent arousal effect on SBP both in the former light and dark phases, a moderate effect on DBP and no effect on HR. Darkness induced decline in BT. BP

  7. High stress, lack of sleep, low school performance, and suicide attempts are associated with high energy drink intake in adolescents.

    Directory of Open Access Journals (Sweden)

    So Young Kim

    Full Text Available Although an association between energy drinks and suicide has been suggested, few prior studies have considered the role of emotional factors including stress, sleep, and school performance in adolescents. This study aimed to evaluate the association of energy drinks with suicide, independent of possible confounders including stress, sleep, and school performance.In total, 121,106 adolescents with 13-18 years olds from the 2014 and 2015 Korea Youth Risk Behavior Web-based Survey were surveyed for age, sex, region of residence, economic level, paternal and maternal education level, sleep time, stress level, school performance, frequency of energy drink intake, and suicide attempts. Subjective stress levels were classified into severe, moderate, mild, a little, and no stress. Sleep time was divided into 6 groups: < 6 h; 6 ≤ h < 7; 7 ≤ h < 8; 8 ≤ h < 9; and ≥ 9 h. School performance was classified into 5 levels: A (highest, B (middle, high, C (middle, D (middle, low, and E (lowest. Frequency of energy drink consumption was divided into 3 groups: ≥ 3, 1-2, and 0 times a week. The associations of sleep time, stress level, and school performance with suicide attempts and the frequency of energy drink intake were analyzed using multiple and ordinal logistic regression analysis, respectively, with complex sampling. The relationship between frequency of energy drink intake and suicide attempts was analyzed using multiple logistic regression analysis with complex sampling.Higher stress levels, lack of sleep, and low school performance were significantly associated with suicide attempts (each P < 0.001. These variables of high stress level, abnormal sleep time, and low school performance were also proportionally related with higher energy drink intake (P < 0.001. Frequent energy drink intake was significantly associated with suicide attempts in multiple logistic regression analyses (AOR for frequency of energy intake ≥ 3 times a week = 3.03, 95

  8. High-Flow, Heated, Humidified Air Via Nasal Cannula Treats CPAP-Intolerant Children With Obstructive Sleep Apnea

    Science.gov (United States)

    Hawkins, Stephen; Huston, Stephanie; Campbell, Kristen; Halbower, Ann

    2017-01-01

    Study Objectives: Continuous positive airway pressure (CPAP) is effective but challenging for children with obstructive sleep apnea (OSA). High-flow air via open nasal cannula (HFNC) as treatment in children remains controversial. We report the efficacy of HFNC in children with OSA and CPAP intolerance, a titration protocol, and a discussion of potential mechanisms. Methods: Patients aged 1 to 18 years with OSA (defined by obstructive apnea-hypopnea index [OAHI] greater than 1 event/h) and CPAP intolerance were enrolled. Routine polysomnography data obtained during 1 night wearing HFNC was compared with diagnostic data by Wilcoxon rank-sum test. Results: Ten school-age subjects (representing all patients attempting HFNC at our institution to date) with varied medical conditions, moderate to severe OSA, and CPAP intolerance wore HFNC from 10 to 50 L/min of room air with oxygen supplementation if needed (room air alone for 6 of the 10). HFNC reduced median OAHI from 11.1 events/h (interquartile range 8.7–18.8 events/h) to 2.1 events/h (1.7–2.2 events/h; P = .002); increased oxyhemoglobin saturation (SpO2) mean from 91.3% (89.6% to 93.5%) to 94.9% (92.4% to 96.0%; P Hawkins S, Huston S, Campbell K, Halbower A. High-flow, heated, humidified air via nasal cannula treats CPAP-intolerant children with obstructive sleep apnea. J Clin Sleep Med. 2017;13(8):981–989. PMID:28728621

  9. High cost of stage IV pressure ulcers.

    Science.gov (United States)

    Brem, Harold; Maggi, Jason; Nierman, David; Rolnitzky, Linda; Bell, David; Rennert, Robert; Golinko, Michael; Yan, Alan; Lyder, Courtney; Vladeck, Bruce

    2010-10-01

    The aim of this study was to calculate and analyze the cost of treatment for stage IV pressure ulcers. A retrospective chart analysis of patients with stage IV pressure ulcers was conducted. Hospital records and treatment outcomes of these patients were followed up for a maximum of 29 months and analyzed. Costs directly related to the treatment of pressure ulcers and their associated complications were calculated. Nineteen patients with stage IV pressure ulcers (11 hospital-acquired and 8 community-acquired) were identified and their charts were reviewed. The average hospital treatment cost associated with stage IV pressure ulcers and related complications was $129,248 for hospital-acquired ulcers during 1 admission, and $124,327 for community-acquired ulcers over an average of 4 admissions. The costs incurred from stage IV pressure ulcers are much greater than previously estimated. Halting the progression of early stage pressure ulcers has the potential to eradicate enormous pain and suffering, save thousands of lives, and reduce health care expenditures by millions of dollars. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. High Pressure Electrochemical Oxygen Generation for ISS, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Giner, Inc. has developed an advanced high pressure electrochemical oxygen concentrator (EOC) that offers a simple alternative to the use of pressure swing...

  11. High-frequency oscillations in human and monkey neocortex during the wake-sleep cycle.

    Science.gov (United States)

    Le Van Quyen, Michel; Muller, Lyle E; Telenczuk, Bartosz; Halgren, Eric; Cash, Sydney; Hatsopoulos, Nicholas G; Dehghani, Nima; Destexhe, Alain

    2016-08-16

    Beta (β)- and gamma (γ)-oscillations are present in different cortical areas and are thought to be inhibition-driven, but it is not known if these properties also apply to γ-oscillations in humans. Here, we analyze such oscillations in high-density microelectrode array recordings in human and monkey during the wake-sleep cycle. In these recordings, units were classified as excitatory and inhibitory cells. We find that γ-oscillations in human and β-oscillations in monkey are characterized by a strong implication of inhibitory neurons, both in terms of their firing rate and their phasic firing with the oscillation cycle. The β- and γ-waves systematically propagate across the array, with similar velocities, during both wake and sleep. However, only in slow-wave sleep (SWS) β- and γ-oscillations are associated with highly coherent and functional interactions across several millimeters of the neocortex. This interaction is specifically pronounced between inhibitory cells. These results suggest that inhibitory cells are dominantly involved in the genesis of β- and γ-oscillations, as well as in the organization of their large-scale coherence in the awake and sleeping brain. The highest oscillation coherence found during SWS suggests that fast oscillations implement a highly coherent reactivation of wake patterns that may support memory consolidation during SWS.

  12. High-frequency oscillations in human and monkey neocortex during the wake–sleep cycle

    Science.gov (United States)

    Le Van Quyen, Michel; Muller, Lyle E.; Telenczuk, Bartosz; Halgren, Eric; Cash, Sydney; Hatsopoulos, Nicholas G.; Dehghani, Nima; Destexhe, Alain

    2016-01-01

    Beta (β)- and gamma (γ)-oscillations are present in different cortical areas and are thought to be inhibition-driven, but it is not known if these properties also apply to γ-oscillations in humans. Here, we analyze such oscillations in high-density microelectrode array recordings in human and monkey during the wake–sleep cycle. In these recordings, units were classified as excitatory and inhibitory cells. We find that γ-oscillations in human and β-oscillations in monkey are characterized by a strong implication of inhibitory neurons, both in terms of their firing rate and their phasic firing with the oscillation cycle. The β- and γ-waves systematically propagate across the array, with similar velocities, during both wake and sleep. However, only in slow-wave sleep (SWS) β- and γ-oscillations are associated with highly coherent and functional interactions across several millimeters of the neocortex. This interaction is specifically pronounced between inhibitory cells. These results suggest that inhibitory cells are dominantly involved in the genesis of β- and γ-oscillations, as well as in the organization of their large-scale coherence in the awake and sleeping brain. The highest oscillation coherence found during SWS suggests that fast oscillations implement a highly coherent reactivation of wake patterns that may support memory consolidation during SWS. PMID:27482084

  13. High-temperature fiber optic pressure sensor

    Science.gov (United States)

    Berthold, J. W.

    1984-01-01

    Attention is given to a program to develop fiber optic methods to measure diaphragm deflection. The end application is intended for pressure transducers capable of operating to 540 C. In this paper are reported the results of a laboratory study to characterize the performance of the fiber-optic microbend sensor. The data presented include sensitivity and spring constant. The advantages and limitations of the microbend sensor for static pressure measurement applications are described. A proposed design is presented for a 540 C pressure transducer using the fiber optic microbend sensor.

  14. GENERATION OF HIGH SHOCK PRESSURES BY LASER PULSES

    OpenAIRE

    Romain , J.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 µm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of ...

  15. High Temperature Characterization of Ceramic Pressure Sensors

    National Research Council Canada - National Science Library

    Fonseca, Michael A; English, Jennifer M; Von Arx, Martin; Allen, Mark G

    2001-01-01

    This work reports functional wireless ceramic micromachined pressure sensors operating at 450 C, with demonstrated materials and readout capability indicating potential extension to temperatures in excess of 600 C...

  16. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  17. Elasticity of stishovite at high pressure

    Science.gov (United States)

    Li, Baosheng; Rigden, Sally M.; Liebermann, Robert C.

    1996-08-01

    The elastic-wave velocities of stishovite, the rutile-structured polymorph of SiO 2, were measured to 3 GPa at room temperature in a piston cylinder apparatus using ultrasonic interferometry on polycrystalline samples. These polycrystalline samples (2-3 mm in length and diameter) were hot-pressed at 14 GPa and 1050°C in a 2000 ton uniaxial split-sphere apparatus (USSA-2000) using fused silica rods as starting material. They were characterized as low porosity (less than 1%), single phase, fine grained, free of cracks and preferred orientation, and acoustically isotropic by using density measurement, X-ray diffraction, scanning electron microscopy, and bench-top velocity measurements. On the basis of subsequent in situ X-ray diffraction study at high P and T on peak broadening on similar specimens, it is evident that the single crystal grains within these polycrystalline aggregates are well equilibrated and that these specimens are free of residual strain. P- and S-wave velocities measured at 1 atm are within 1.5% of the Hashin-Shtrikman bounds calculated from single-crystal elastic moduli. Measured pressure derivatives of the bulk and shear moduli, K' 0 = 5.3 ± 0.1 and G' 0 = 1.8 ± 0.1, are not unusual compared with values measured for other transition zone phases such as silicate spinel and majorite garnet. Isothermal compression curves calculated with the measured values of K0 and K' 0 agree well with experimental P-V data to 16 GPa. The experimental value of dG /dP is in excellent agreement with predictions based on elasticity systematics. Theoretical models are not yet able to replicate the measured values of K' 0 and G' 0.

  18. Bi-level positive airway pressure ventilation for treating heart failure with central sleep apnea that is unresponsive to continuous positive airway pressure.

    Science.gov (United States)

    Dohi, Tomotaka; Kasai, Takatoshi; Narui, Koji; Ishiwata, Sugao; Ohno, Minoru; Yamaguchi, Tetsu; Momomura, Shin-Ichi

    2008-07-01

    Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) is associated with a poor prognosis in patients with heart failure (HF). However, some patients do not respond to continuous positive airway pressure (CPAP), so other therapeutic modalities should be considered, such as bi-level positive airway pressure (PAP), which also assists respiration and might be effective for such patients. The 20 patients with HF because of left ventricular systolic dysfunction were assessed: 8 had ischemic etiology, and all had severe CSA according to the apnea - hypopnea index (AHI) determined by polysomnography. All diagnosed patients underwent repeat polysomnography using CPAP. The AHI improved significantly in 11 (AHI or=15). Bi-level PAP titration significantly improved the AHI in the latter group. Those who were unresponsive to CPAP had significantly lower PaCO(2), higher plasma brain natriuretic peptide (BNP), longer mean duration of CSR and fewer obstructive episodes than CPAP responders. After 6 months of positive airway support with either CPAP (n=9) or bi-level PAP (n=7), BNP levels significantly decreased and left ventricular ejection fraction significantly increased. Bi-level PAP could be an effective alternative for patients with HF and pure CSR-CSA who are unresponsive to CPAP.

  19. High-pressure system for Compton scattering experiments

    International Nuclear Information System (INIS)

    Oomi, G.; Honda, F.; Kagayama, T.; Itoh, F.; Sakurai, H.; Kawata, H.; Shimomura, O.

    1998-01-01

    High-pressure apparatus for Compton scattering experiments has been developed to study the momentum distribution of conduction electrons in metals and alloys at high pressure. This apparatus was applied to observe the Compton profile of metallic Li under pressure. It was found that the Compton profile at high pressure could be obtained within several hours by using this apparatus and synchrotron radiation. The result on the pressure dependence of the Fermi momentum of Li obtained here is in good agreement with that predicted from the free-electron model

  20. Advances in high pressure science and technology: proceedings of the fourth national conference on high pressure science and technology

    International Nuclear Information System (INIS)

    Yousuf, Mohammad; Subramanian, N.; Govinda Rajan, K.

    1997-09-01

    The proceedings of the fourth National Conference on High Pressure Science and Technology covers a wide area of research and development activities in the field of high pressure science and technology, broadly classified into the following themes: mechanical behaviour of materials; instrumentation and methods in high pressure research; pressure calibration, standards and safety aspects; phase transitions; shock induced reactions; mineral science, geophysics, geochemistry and planetary sciences; optical, electronic and transport properties; synthesis of materials; soft condensed matter physics and liquid crystals; computational methods in high pressure research. Papers relevant to INIS are indexed separately

  1. Modeling, Parameters Identification, and Control of High Pressure Fuel Cell Back-Pressure Valve

    Directory of Open Access Journals (Sweden)

    Fengxiang Chen

    2014-01-01

    Full Text Available The reactant pressure is crucial to the efficiency and lifespan of a high pressure PEMFC engine. This paper analyses a regulated back-pressure valve (BPV for the cathode outlet flow in a high pressure PEMFC engine, which can achieve precisely pressure control. The modeling, parameters identification, and nonlinear controller design of a BPV system are considered. The identified parameters are used in designing active disturbance rejection controller (ADRC. Simulations and extensive experiments are conducted with the xPC Target and show that the proposed controller can not only achieve good dynamic and static performance but also have strong robustness against parameters’ disturbance and external disturbance.

  2. Neutron powder diffraction under high pressure at J-PARC

    International Nuclear Information System (INIS)

    Utsumi, Wataru; Kagi, Hiroyuki; Komatsu, Kazuki; Arima, Hiroshi; Nagai, Takaya; Okuchi, Takuo; Kamiyama, Takashi; Uwatoko, Yoshiya; Matsubayashi, Kazuyuki; Yagi, Takehiko

    2009-01-01

    It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a 'day-one' high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

  3. High Pressure, High Gradient RF Cavities for Muon Beam Cooling

    CERN Document Server

    Johnson, R P

    2004-01-01

    High intensity, low emittance muon beams are needed for new applications such as muon colliders and neutrino factories based on muon storage rings. Ionization cooling, where muon energy is lost in a low-Z absorber and only the longitudinal component is regenerated using RF cavities, is presently the only known cooling technique that is fast enough to be effective in the short muon lifetime. RF cavities filled with high-pressure hydrogen gas bring two advantages to the ionization technique: the energy absorption and energy regeneration happen simultaneously rather than sequentially, and higher RF gradients and better cavity breakdown behavior are possible than in vacuum due to the Paschen effect. These advantages and some disadvantages and risks will be discussed along with a description of the present and desired RF R&D efforts needed to make accelerators and colliders based on muon beams less futuristic.

  4. Curative effect of continuous positive airway pressure on treatment of patients with obstructive sleep apnea hypopnea syndrome and hypertension: A Meta-analysis

    Directory of Open Access Journals (Sweden)

    Bi-fang MIAO

    2016-12-01

    Full Text Available Objective  To systematically evaluate the curative effect of continuous positive airway pressure (CPAP on treatment of patients with obstructive sleep apnea hypopnea syndrome (OSAHS and hypertension. Methods  The data were retrieved of randomized controlled trials (RCTs about the curative effect of CPAP on treatment of patients with OSAHS and hypertension from PubMed, Cochrane Library, CNKI, VIP, CBM and WanFang database from inception to Oct. 2015. Literature screening, data extraction and risk bias assessment were performed by two independent reviewers, and meta-analysis was then carried out by using RevMan 5.3 software. Results  A total of 16 RCTs involving 2101 patients were included. Meta-analysis revealed that, compared with the antihypertensive drug therapy alone, CPAP plus antihypertensive drug therapy significantly reduced the daytime systolic pressure [MD=–12.60, 95%CI(–17.68 to –7.52, P<0.00001], nighttime systolic pressure [MD=–21.90, 95%CI(–25.94 to –17.86, P<0.00001] and nighttime diastolic pressure [MD=–11.90, 95%CI(–15.44 to –8.36, P<0.00001], while created no significant difference in daytime diastolic pressure, 24-h mean systolic pressure and 24-h mean diastolic pressure in a following-up less than 12 weeks. Whereas in the following-up no less than 12 weeks, compared with the antihypertensive drug therapy alone, CPAP plus antihypertensive drug therapy significantly reduced the 24-h mean systolic pressure [MD=–7.88, 95%CI(–12.09 to –3.66, P=0.00002], 24-h mean diastolic pressure [MD=–5.14, 95%CI(–6.00 to –4.28, P<0.00001], daytime systolic pressure [MD=–5.89, 95%CI(–8.79 to –2.98, P<0.0001], daytime diastolic pressure [MD=–4.34, 95%CI(–6.32 to –2.36, P<0.0001]; nighttime systolic pressure [MD=–7.06, 95%CI(–11.12 to –2.99, P=0.0007] and nighttime diastolic pressure [MD=–4.49, 95%CI (–7.39 to –1.58, P=0.006]. Conclusions  The current evidences suggest that on the basis

  5. Nasal pillows as an alternative interface in patients with obstructive sleep apnoea syndrome initiating continuous positive airway pressure therapy.

    LENUS (Irish Health Repository)

    Ryan, Silke

    2012-02-01

    Side-effects directly due to the nasal mask are common in patients with obstructive sleep apnoea syndrome (OSAS) commencing continuous positive airway pressure (CPAP). Recently, nasal pillows have been designed to overcome these issues. Limited evidence exists of the benefits and effectiveness of these devices. Twenty-one patients (19 male, 49+\\/-10years) with the established diagnosis of OSAS [apnoea\\/hypopnoea index (AHI): 52+\\/-22] and who had a successful CPAP titration were commenced on CPAP therapy (10+\\/-2cmH2O), and randomized to 4weeks of a nasal pillow (P) and a standard nasal mask (M) in a crossover design. Outcome measures were objective compliance, AHI, quality of life, Epworth Sleepiness Score (ESS) and CPAP side-effects. There was no difference in compliance (M versus P: 5.1+\\/-1.9h versus 5.0+\\/-1.7h; P=0.701) and AHI (2.6+\\/-2.7 versus 3.0+\\/-2.9; P=0.509). Quality of life and ESS improved with CPAP, but there was no difference in the extent of improvement between both devices. Usage of nasal pillows resulted in less reported pressure on the face and more subjects found the nasal pillow the more comfortable device. However, there was no clear overall preference for either device at the end of the study (mask=57%, pillow=43%; P=0.513). The applied CPAP pressure did not correlate with compliance, AHI and ESS. Furthermore, no differences in outcome parameters were noted comparing groups with CPAP pressure <10 and >\\/=10cm H(2) O. Nasal pillows are equally effective in CPAP therapy, but do not generally lead to improved compliance.

  6. Pressure effects on high temperature steam oxidation of Zircaloy-4

    International Nuclear Information System (INIS)

    Park, Kwangheon; Kim, Kwangpyo; Ryu, Taegeun

    2000-01-01

    The pressure effects on Zircaloy-4 (Zry-4) cladding in high temperature steam have been analyzed. A double layer autoclave was made for the high pressure, high temperature oxidation tests. The experimental test temperature range was 700 - 900 deg C, and pressures were 0.1 - 15 MPa. Steam partial pressure turns out to be an important one rather than total pressure. Steam pressure enhances the oxidation rate of Zry-4 exponentially. The enhancement depends on the temperature, and the maximum exists between 750 - 800 deg C. Pre-existing oxide layer decreases the enhancement about 40 - 60%. The acceleration of oxidation rate by high pressure team seems to be originated from the formation of cracks by abrupt transformation of tetragonal phase in oxide, where the un-stability of tetragonal phase comes from the reduction of surface energy by steam. (author)

  7. High pressure apparatus for neutron scattering at low temperature

    International Nuclear Information System (INIS)

    Munakata, Koji; Uwatoko, Yoshiya; Aso, Naofumi

    2010-01-01

    Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity and magnetically ordered non-Fermi liquid have been observed. Up to now, many scientists have developed a lot of high pressure apparatus for each purpose. The characteristic features of various materials and pressure transmitting media for use of high pressure apparatus are reported. Then, two kinds of clamp type high-pressure cell designed for low-temperature neutron diffraction measurements are shown; one is a piston cylinder type high-pressure cell which can be attached to the dilution refrigerator, and the other one is a newly-developed cubic anvil type high-pressure cell which can generate pressure above 7GPa. We also introduce the results of magnetic neutron scattering under pressure on a pressure-induced superconducting ferromagnet UGe 2 in use of the piston cylinder type clamp cell, and those on an iron arsenide superconductor SrFe 2 As 2 in use of the cubic anvil type clamp cell. (author)

  8. Partial sleep in the context of augmentation of brain function.

    Directory of Open Access Journals (Sweden)

    Ivan N. Pigarev

    2014-05-01

    Full Text Available Inability to solve complex problems or errors in decision making is often attributed to poor brain processing, and raises the issue of brain augmentation. Investigation of neuronal activity in the cerebral cortex in the sleep-wake cycle offers insights into the mechanisms underlying the reduction in mental abilities for complex problem solving. Some cortical areas may transit into a sleep state while an organism is still awake. Such local sleep would reduce behavioral ability in the tasks for which the sleeping areas are crucial. The studies of this phenomenon have indicated that local sleep develops in high order cortical areas. This is why complex problem solving is mostly affected by local sleep, and prevention of local sleep might be a potential way of augmentation of brain function. For this approach to brain augmentation not to entail negative consequences for the organism, it is necessary to understand the functional role of sleep. Our studies have given an unexpected answer to this question. It was shown that cortical areas that process signals from extero- and proprioreceptors during wakefulness, switch to the processing of interoceptive information during sleep. It became clear that during sleep all computational power of the brain is directed to the restoration of the vital functions of internal organs. These results explain the logic behind the initiation of total and local sleep. Indeed, a mismatch between the current parameters of any visceral system and the genetically determined normal range would provide the feeling of tiredness, or sleep pressure. If an environmental situation allows falling asleep, the organism would transit to a normal total sleep in all cortical areas. However, if it is impossible to go to sleep immediately, partial sleep may develop in some cortical areas in the still behaviorally awake organism. This local sleep may reduce both the intellectual power and the restorative function of sleep for visceral

  9. Verifying the Relative Efficacy between Continuous Positive Airway Pressure Therapy and Its Alternatives for Obstructive Sleep Apnea: A Network Meta-analysis

    Directory of Open Access Journals (Sweden)

    Tingwei Liu

    2017-06-01

    Full Text Available Obstructive sleep apnea (OSA is a common breathing disorder, and continuous positive airway pressure (CPAP therapy together with its alternatives has been developed to treat this disease. This network meta-analysis (NMA was aimed to compare the efficacy of treatments for OSA. Cochrane Library, MEDLINE, and Embase were searched for eligible studies. A conventional and NMA was carried out to compare all therapies. Sleeping characteristics, including Apnea–Hypopnea Index (AHI, Epworth Sleepiness Scale (ESS, arterial oxygen saturation, and arousal index (AI, and changes of blood pressure were selected as outcomes. A total of 84 studies were finally included after rigorous screenings. For the primary outcomes of AHI and ESS, the value of auto-adjusting positive airway pressure (APAP, CPAP, and oral appliance (OA all showed statistically reduction compared with inactive control (IC. Similar observation was obtained in AI, with treatments of the three active interventions. A lower effect of IC in SaO2 was exhibited when compared with APAP, CPAP, and OA. Similar statistically significant results were presented in 24 h systolic blood pressure and 24 h DBP when comparing with CPAP. Our NMA identified CPAP as the most efficacious treatment for OSA patients after the evaluation of sleeping characteristics and blood pressures. In addition, more clinical trials are needed for further investigation due to the existence of inconsistency observed in this study.

  10. Cavitation-induced reactions in high-pressure carbon dioxide

    NARCIS (Netherlands)

    Kuijpers, M.W.A.; van Eck, D.; Kemmere, M.F.; Keurentjes, J.T.F.

    2002-01-01

    The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of

  11. Viscosity of liquid sulfur under high pressure

    International Nuclear Information System (INIS)

    Terasaki, Hidenori; Kato, T; Funakoshi, K; Suzuki, A; Urakawa, S

    2004-01-01

    The viscosity of liquid sulfur up to 9.7 GPa and 1067 K was measured using the in situ x-ray radiography falling sphere method. The viscosity coefficients were found to range from 0.11 to 0.69 Pa s, and decreased continuously with increasing pressure under approximately constant homologous temperature conditions. The observed viscosity variation suggests that a gradual structural change occurs in liquid sulfur with pressure up to 10 GPa. The L-L' transition in liquid sulfur proposed by Brazhkin et al (1991 Phys. Lett. A 154 413) from thermobaric measurements has not been confirmed by the present viscometry

  12. Announcement: National High Blood Pressure Education Month - May 2016.

    Science.gov (United States)

    2016-05-27

    May is National High Blood Pressure Education Month. High blood pressure (hypertension) is a major contributor to heart disease and stroke, two leading causes of death in the United States.* High blood pressure affects one third of U.S. adults, or approximately 75 million persons, yet approximately 11 million of these persons are not aware they have hypertension, and approximately 18 million are not being treated (unpublished data) (1,2).

  13. Safety regulation on high-pressure gas and gas business

    International Nuclear Information System (INIS)

    Kim, Du Yeoung; An, Dae Jun

    1978-09-01

    This book is divided into two parts. The first part introduces safety regulation on high-pressure gas, enforcement ordinance on safety regulation about high-pressure gas and enforcement regulation on safety regulation about high-pressure gas. The second part indicates regulations on gas business such as general rules, gas business gas supplies, using land, supervision, supple mentary rules and penalty. It has two appendixes on expected questions and questions during last years.

  14. Teaming Up Against High Blood Pressure PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    Nearly one-third of American adults have high blood pressure, and more than half of them don’t have it under control. Simply seeing a doctor and taking medications isn’t enough for many people who have high blood pressure. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.

  15. Transportable, small high-pressure preservation vessel for cells

    International Nuclear Information System (INIS)

    Kamimura, N; Sotome, S; Shimizu, A; Nakajima, K; Yoshimura, Y

    2010-01-01

    We have previously reported that the survival rate of astrocytes increases under high-pressure conditions at 4 0 C. However, pressure vessels generally have numerous problems for use in cell preservation and transportation: (1) they cannot be readily separated from the pressurizing pump in the pressurized state; (2) they are typically heavy and expensive due the use of materials such as stainless steel; and (3) it is difficult to regulate pressurization rate with hand pumps. Therefore, we developed a transportable high-pressure system suitable for cell preservation under high-pressure conditions. This high-pressure vessel has the following characteristics: (1) it can be easily separated from the pressurizing pump due to the use of a cock-type stop valve; (2) it is small and compact, is made of PEEK and weighs less than 200 g; and (3) pressurization rate is regulated by an electric pump instead of a hand pump. Using this transportable high-pressure vessel for cell preservation, we found that astrocytes can survive for 4 days at 1.6 MPa and 4 0 C.

  16. Magnetic structures of erbium under high pressure

    DEFF Research Database (Denmark)

    Kawano, S.; Lebech, B.; Achiwa, N.

    1993-01-01

    Neutron diffraction studies of the magnetic structures of erbium metal at 4.5 K and 11.5 kbar hydrostatic pressure have revealed that the transition to a conical structure at low temperatures is suppressed and that the cycloidal structure, with modulation vector Q congruent-to (2/7 2pi/c)c persists...

  17. Generation of high shock pressures by laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Romain, J.P. (GRECO ILM, Laboratoire d' Energetique et Detonique, E.N.S.M.A., 86 - Poitiers (France))

    1984-11-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 ..mu..m wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined.

  18. Generation of high shock pressures by laser pulses

    International Nuclear Information System (INIS)

    Romain, J.P.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 μm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined

  19. Vibrational spectroscopy at high external pressures the diamond anvil cell

    CERN Document Server

    Ferraro, John R

    1984-01-01

    Vibrational Spectroscopy at High External Pressures: The Diamond Anvil Cell presents the effects of high pressure on the vibrational properties of materials as accomplished in a diamond anvil cell (DAC). The DAC serves the dual purpose of generating the pressures and being transparent to infrared radiation, allowing the observation of changes caused by pressure. The optical probes highlighted will deal principally with infrared and Raman scattering, although some observations in the visible region will also be presented. The book begins with a discussion of the effects of pressure and pres

  20. Magnetization at high pressure in CeP

    Science.gov (United States)

    Naka, T.; Matsumoto, T.; Okayama, Y.; Môri, N.; Haga, Y.; Suzuki, T.

    1995-02-01

    We have investigated the pressure dependence of magnetization below 60 K up to 1.6 GPa in the low-carrier concentration system CeP showing two step transitions at T = TL and TH under high pressure. At high pressure, M( P, T) exhibits a maximum at around the lower transition temperature TL. This behavior implies that the magnetic state changes at TL. The pressure dependence of isothermal magnetization M( P) is different above and below TL. In fact, M( P) below TL exhibits a maximum at around 1.4 GPa, whereas M( P) above TL increases steeply with pressure up to 1.6 GPa.

  1. High pressure studies of fluorenone emission in plastic media

    International Nuclear Information System (INIS)

    Mitchell, D.J.; Schuster, G.B.; Drickamer, H.G.

    1977-01-01

    The energy and the quantum efficiency for fluorenone fluorescence in the crystalline state and in polymeric matrices was measured as a function of external pressure over the range 0--140 kbar. The application of high pressure induces changes in the quantum yield, which ranges from 0.001 at low pressure to a maximum of approx.0.1 at high pressure in hydrocarbon plastics. These results are interpreted as arising from the decrease in the energy of the lowest ππ excited singlet state relative to other relevant states as the external pressure is increased

  2. Proposed dedicated high pressure beam lines at CHESS

    International Nuclear Information System (INIS)

    Ruoff, A.L.; Vohra, Y.K.; Bassett, W.A.; Batterman, B.W.; Bilderback, D.H.

    1988-01-01

    An instrumentation proposal for dedicated high pressure beam lines at CHESS is described. It is the purpose of this proposed program to provide researchers in high pressure science with beam lines for X-ray diffraction studies in the megabar regime. This will involve radiation from a bending magnet as well as from a wiggler. Examples of the high pressure results up to 2.16 Mbar are shown. Diffraction patterns from bending magnet and wiggler beams are shown and compared. The need for this facility by the high pressure community is discussed. (orig.)

  3. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  4. High pressure argon detector of high energy neutrinos

    International Nuclear Information System (INIS)

    Vishnevskii, A.V.; Golutvin, I.A.; Sarantsev, V.L.; Sviridov, V.A.; Dolgoshein, B.A.; Kalinovskii, A.N.; Sosnovtsev, V.V.; Chernyatin, V.K.; Kaftanov, V.S.; Khovanskii, V.D.; Shevchenko, V.G.

    1979-01-01

    In the present paper, we suggest an electron neutrino detector of a new type where track information is available for all charged particles. As a working medium we use Argon compressed up to a pressure of 100 to 150 atm (approximately 0.2-0.3 g/cm 3 ). The spatial reconstruction of tracks are accomplished with an accuracy not inferior to that of bubble chambers. The detector has a high sensitivity in ionization measurements. An assembly with a working medium mass of approximately 100 tons seem to be realisable. This makes it possible to perform tasks with cross-sections of (10 -5 + 10 -3 ) x delty tot at an intensity of the neutrino beam which is available in present-day accelerators. (orig.)

  5. Blood pressure in childhood : epidemiological probes into the aetiology of high blood pressure

    NARCIS (Netherlands)

    A. Hofman (Albert)

    1983-01-01

    textabstractHigh arterial blood pressure takes a heavy toll in western populations (1 ). Its causes are still largely unknown, but its sequelae, a variety of cardiovascular and renal diseases, have been referred to as "a modern scourge" (2). High blood pressure of unknown cause, or

  6. The role of severity of obstructive sleep apnea measured by apnea-hypopnea index in predicting compliance with pressure therapy, a meta-analysis.

    Science.gov (United States)

    Madbouly, Essam M; Nadeem, Rashid; Nida, Mahwish; Molnar, Janos; Aggarwal, Saurabh; Loomba, Rohit

    2014-01-01

    Obstructive sleep apnea (OSA) is associated with diabetes, hypertension, stroke, coronary artery disease, and premature death. Positive airway pressure (PAP) is the mainstay of therapy. Despite its effective treatment with PAP therapy, noncompliance remains high. Many factors determine compliance. The role of severity of OSA measured by the apnea-hypopnea index (AHI) remains controversial. Meta-analysis of studies examining this role of AHI was performed. A systematic review of the medical literature was conducted using PubMed and Cochrane library by utilizing different combinations of key words: sleep apnea, AHI, compliance, and nonadherence. Inclusion criteria were English articles; Studies with adult population; with 2 groups of patients (compliant and noncompliant); Studies utilizing objective definition of compliance (PAP usage of >4 hours per night for 70% of days or usage >5 d/wk and for >4 hours per night). Studies were analyzed by standard methods of meta-analysis. The studies were heterogeneous for AHI; therefore, the random effect model was used. Six hundred forty-one manuscripts were found. Of these, 230 were found to be appropriate for full text evaluation. Thirty-one met inclusion criteria. Twelve of these studies used objective criteria for PAP compliance and were hence included in meta-analysis. All the subjects had OSA determined by polysomnography, for whom PAP was employed. Compliance to PAP therapy was evaluated after a period of time ranging from 4 weeks to 8 years. There were 1438 subjects included in the meta-analysis; 886 subjects were PAP compliant, whereas 552 subjects were noncompliant. A greater AHI was found in PAP compliant patients. The mean difference between compliant and noncompliant groups was 5.9 (95% confidence interval: 0.19-11.67, P compliance.

  7. High pressure behaviour of uranium mono pnictides

    International Nuclear Information System (INIS)

    Pagare, Gitanjali; Ojha, Poonam; Sanyal, S.P.; Aynyas, Mahendra

    2006-01-01

    The pressure induced structural phase transition of three actinide mono pnictides AX (A=U and X=As, Sb, Bi), have been studied theoretically using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 5f electrons of the actinide (uranium) ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band. The calculated compression curves are compared with the experimental results. These compounds exhibits first order crystallographic phase transition from their NaCl (B 1 ) phase to CsCl (B 2 ) phase at 17GPa, 9.5GPa and 5.3 GPa respectively. The NaCl phase possesses lower energy than CsCl phase and stable at ambient pressure. (author)

  8. High pressure multiple shock response of aluminum

    International Nuclear Information System (INIS)

    Lawrence, R.J.; Asay, J.R.

    1977-01-01

    It is well known that both dynamic yield strength and rate-dependent material response exert direct influence on the development of surface and interface instabilities under conditions of strong shock loading. A detailed understanding of these phenomena is therefore an important aspect of the analysis of dynamic inertial confinement techniques which are being used in such applications as the generation of controlled thermonuclear fusion. In these types of applications the surfaces and interfaces under consideration can be subjected to cyclic loading characterized by shock pressures on the order of 100 GPa or more. It thus becomes important to understand how rate effects and material strength differ from the values observed in the low pressure regime where they are usually measured, as well as how they are altered by the loading history

  9. Associations between sleep disturbance and mental health status: a longitudinal study of Japanese junior high school students.

    Science.gov (United States)

    Kaneita, Yoshitaka; Yokoyama, Eise; Harano, Satoru; Tamaki, Tetsuo; Suzuki, Hiroyuki; Munezawa, Takeshi; Nakajima, Hiromi; Asai, Takami; Ohida, Takashi

    2009-08-01

    A limited number of longitudinal studies have addressed the association between sleep disturbance and mental health status among adolescents. To examine whether each of these is a risk factor for the onset of the other, we conducted a prospective longitudinal study of Japanese adolescents. In 2004, we performed a baseline study of students attending three private junior high schools in Tokyo, and in 2006, a follow-up study was performed on the same population. The mean age of the subjects was 13 years. The Pittsburgh Sleep Quality Index was used to evaluate sleep disturbance, and the 12-item General Health Questionnaire was used to evaluate mental health status. The subjects were 698 students, of whom 516 were suitable for analysis. The incidence of newly developed poor mental health status during the 2 years leading to the follow-up study was 35.1%. New onset of poor mental health status was significantly associated with new onset of sleep disturbance and lasting sleep disturbance. The incidence of sleep disturbance during the 2 years leading to the follow-up study was 33.3%. New onset of sleep disturbance was significantly associated with new onset of poor mental health status and lasting poor mental health status. Sleep disturbance and poor mental health status increase each other's onset risk.

  10. Designing high pressure containers for research- principles and applications

    International Nuclear Information System (INIS)

    Anandkumar, V.

    1997-01-01

    The high pressure scientist looks for a well engineered pressure apparatus for high pressure experiments for 1 kbar (0.1 GPa) and above. Often, a variety of difficulties including the choice of materials, design configuration, optimum utilisation of the strength of materials used in the design, are encountered. This article is intended to help the high pressure scientist to select the design approach for pressure retaining container. The limitations imposed by the strength of available materials and engineering standards in building high pressure containers are discussed. Engineering solutions to overcome these limitations with optimal utilisation of the strength of the materials are also discussed. Novel methods to boost up the pressure retaining capacity like multilayered design and autofrettaging are compared along with their relative advantages and disadvantages. Special methods by which it is possible to attain pressures which are several times the yield strength of the materials of construction are presented. In this aspects such as the basis of the codes and their relevance in the design of high pressure equipment will also be described. Discussions are centered around the methods to tackle situations where experimental constraints dictate requirements of pressures higher than those permitted by design codes. Safety features are also discussed. (author)

  11. High risk for obstructive sleep apnea in patients with acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Carla Renata Silva Andrechuk

    2015-10-01

    Full Text Available Objectives: to stratify the risk for obstructive sleep apnea in patients with acute myocardial infarction, treated at a public, tertiary, teaching hospital of the state of São Paulo, Brazil, and to identify related sociodemographic and clinical factors.Method: cross-sectional analytical study with 113 patients (mean age 59.57 years, 70.8% male. A specific questionnaire was used for the sociodemographic and clinical characterization and the Berlin Questionnaire for the stratification of the risk of obstructive sleep apnea syndrome.Results: the prevalence of high risk was 60.2% and the outcome of clinical worsening during hospitalization was more frequent among these patients. The factors related to high risk were body mass index over 30 kg/m2, arterial hypertension and waist circumference indicative of cardiovascular risk, while older age (60 years and over constituted a protective factor.Conclusion: considering the high prevalence of obstructive sleep apnea and its relation to clinical worsening, it is suggested that nurses should monitor, in their clinical practice, people at high risk for this syndrome, guiding control measures of modifiable factors and aiming to prevent the associated complications, including worsening of cardiovascular diseases.

  12. [Comorbidities of heart failure: sleep apnea].

    Science.gov (United States)

    Woehrle, H; Oldenburg, O; Stadler, S; Arzt, M

    2018-05-01

    Since sleep apnea often occurs in heart failure, physicians regularly need to decide whether further diagnostic procedures and/or treatment are required. Which types of sleep apnea occur in heart failure patients? When is treatment needed? Which treatments and treatment goals are appropriate? Clinical trials and guidelines as well as their implementation in clinical practice are discussed. At least 40% of patients with heart failure, both with reduced and preserved left ventricular ejection fraction (HFrEF and HFpEF, respectively), suffer from relevant sleep apnea. In heart failure patients both obstructive and central sleep apnea are associated with increased mortality. In HFrEF as well as in HFpEF patients with obstructive sleep apnea, treatment with continuous positive airway pressure (CPAP) achieves symptomatic and functional improvements. In patients with HFpEF, positive airway pressure treatment of central sleep apnea may be beneficial. In patients with HFrEF and left ventricular ejection fraction ≤45%, adaptive servoventilation is contraindicated. Sleep apnea is highly prevalent in heart failure patients and its treatment in specific patient groups can improve symptoms and functional outcomes. Thus, testing for sleep apnea is recommended.

  13. Solid gas reaction phase diagram under high gas pressure

    International Nuclear Information System (INIS)

    Ishizaki, K.

    1992-01-01

    This paper reports that to evaluate which are the stable phases under high gas pressure conditions, a solid-gas reaction phase diagram under high gas pressure (HIP phase diagram) has been proposed by the author. The variables of the diagram are temperature, reactant gas partial pressure and total gas pressure. Up to the present time the diagrams have been constructed using isobaric conditions. In this work, the stable phases for a real HIP process were evaluated assuming an isochoric condition. To understand the effect of the total gas pressure on stability is of primary importance. Two possibilities were considered and evaluated, those are: the total gas pressure acts as an independent variable, or it only affects the fugacity values. The results of this work indicate that the total gas pressure acts as an independent variable, and in turn also affects the fugacity values

  14. Practical conditions in the neutron diffraction under high pressure

    International Nuclear Information System (INIS)

    Kamigaki, Kazuo; Ohashi, Masayoshi

    1993-01-01

    Practical analysis is made on some conditions in utilizing neutrons for the study of atomistic structure of materials under high pressure. Investigation is made on the geometrical conditions; size of the specimen, width of slits, and the rate of extra-scattering. Experiments are performed on the effects of absorption by high pressure cell and the disturbance due to an overlapping of diffraction peaks. An observation is presented on the pressure-induced transformation in RbBr. (author)

  15. [Treatment compliance with continuous positive airway pressure device among adults with obstructive sleep apnea (OSA): how many adhere to treatment?].

    Science.gov (United States)

    Sarrell, E Michael; Chomsky, Ofer; Shechter, Dalia

    2013-03-01

    Obstructive sleep apnea syndrome (OSA) afflicts approximately 5% of the adult population and increases with age. The gold standard treatment is with the Continuous Positive Airways Pressure (CPAP) machine. Well-designed prospective trials to elucidate long term compliance with CPAP machine are rare. Assessing compliance and long-term use of CPAP machines among patients with OSA who were referred for treatment with this machine. A 4 years prospective cohort observational study was conducted using telephone interviews of 371 newly diagnosed patients with moderate to severe OSA, who received a specialist recommendation to use the CPAP machine which was bought and adjusted to their use. At the end of the first year, 126 (34%) of the OSA patients used the CPAP machine on a nightly basis (regular users), 120 (32.3%) had not used it at all, and 125 (33.7%) had used it only intermittently. The number of regular users increased between the 1st and 2nd year from 126 (34%), to 163 (44%) (p < 0.07) due to additions from the intermittent users group. The non-users group grew from 120 (32.3%) in the first year, and every year afterwards, up to 221 (59.6%) in the fourth year (p < 0.02). In contrast, there was a significant decrease in the intermittent users group, which declined from 125 (33.7%) in the first year to only 18 (4.8%) in the 4th year (p < 0.005). Most of the patients (92.9%) were males. The average age of the regular users was 59.6 years (+/- 11), which was higher in comparison to 55.9 years (+/- 10.3) for the non-users or 58.9 years (+/- 12.6) among the intermittent users (p = 0.064). There were no statistical differences in co-morbidities or demographics between the three groups. However, the regular users were found to have a higher score in the Epworth Sleepiness Scale (ESS) and a minimal arterial oxygen saturation (SaO2) level lower than the patients in the non-users and intermittent users groups (p = 0.019 and p = 0.03 respectively). Four years follow

  16. Pressurizer pump reliability analysis high flux isotope reactor

    International Nuclear Information System (INIS)

    Merryman, L.; Christie, B.

    1993-01-01

    During a prolonged outage from November 1986 to May 1990, numerous changes were made at the High Flux Isotope Reactor (HFIR). Some of these changes involved the pressurizer pumps. An analysis was performed to calculate the impact of these changes on the pressurizer system availability. The analysis showed that the availability of the pressurizer system dropped from essentially 100% to approximately 96%. The primary reason for the decrease in availability comes because off-site power grid disturbances sometimes result in a reactor trip with the present pressurizer pump configuration. Changes are being made to the present pressurizer pump configuration to regain some of the lost availability

  17. The prevalence of probable delayed-sleep-phase syndrome in students from junior high school to university in Tottori, Japan.

    Science.gov (United States)

    Hazama, Gen-i; Inoue, Yuichi; Kojima, Kazushige; Ueta, Toshiyuki; Nakagome, Kazuyuki

    2008-09-01

    Delayed sleep phase syndrome (DSPS) is a circadian rhythm sleep disorder with a typical onset in the second decade of life. DSPS is characterized by the sleep-onset insomnia and the difficulty in waking at the desired time in the morning. Although DSPS is associated with inability to attend school, the prevalence has been controversial. To elucidate a change in the prevalence of DSPS among young population, epidemiological survey was conducted on Japanese students. A total of 4,971 students of junior high school, senior high school, and university were enrolled in this cross sectional study in Tottori Prefecture. They answered anonymous screening questionnaire regarding school schedule, sleep hygiene and symptomatic items of sleep disorders. The prevalence of probable DSPS was estimated at 0.48% among the total subject students without gender difference. In university, the prevalence of the last year students showed the highest value (1.66%), while that of the first year students showed the lowest value (0.09%) among all school years from junior high school to university. The prevalence increased with advancing university school years. Thus, a considerable number of Japanese students are affected with DSPS. Senior students of university are more vulnerable to the disorder than younger students. Appropriate school schedule may decrease the mismatch between the individual's sleep-wake cycle and the school schedule. Promotion of a regular sleep habit is necessary to prevent DSPS among this population.

  18. Sleep Duration and Injury-Related Risk Behaviors Among High School Students--United States, 2007-2013.

    Science.gov (United States)

    Wheaton, Anne G; Olsen, Emily O'Malley; Miller, Gabrielle F; Croft, Janet B

    2016-04-08

    Insufficient sleep is common among high school students and has been associated with an increased risk for motor vehicle crashes (1), sports injuries (2), and occupational injuries (3). To evaluate the association between self-reported sleep duration on an average school night and several injury-related risk behaviors (infrequent bicycle helmet use, infrequent seatbelt use, riding with a driver who had been drinking, drinking and driving, and texting while driving) among U.S. high school students, CDC analyzed data from 50,370 high school students (grades 9-12) who participated in the national Youth Risk Behavior Surveys (YRBSs) in 2007, 2009, 2011, or 2013. The likelihood of each of the five risk behaviors was significantly higher for students who reported sleeping ≤7 hours on an average school night; infrequent seatbelt use, riding with a drinking driver, and drinking and driving were also more likely for students who reported sleeping ≥10 hours compared with 9 hours on an average school night. Although insufficient sleep directly contributes to injury risk, some of the increased risk associated with insufficient sleep might be caused by engaging in injury-related risk behaviors. Intervention efforts aimed at these behaviors might help reduce injuries resulting from sleepiness, as well as provide opportunities for increasing awareness of the importance of sleep.

  19. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    against conventional technologies for hydrogen production, such as natural gas reforming, the production and investment costs have to be reduced. A reduction of the investment costs may be achieved by increasing the operational pressure and temperature of the electrolyzer, as this will result in: 1.......3 A cm-2 combined with relatively small production costs may lead to both reduced investment and operating costs for hydrogen and oxygen production. One of the produced electrolysis cells was operated for 350 h. Based on the successful results a patent application covering this novel cell was filed...

  20. High-Performance Pressure Sensor for Monitoring Mechanical Vibration and Air Pressure

    Directory of Open Access Journals (Sweden)

    Yancheng Meng

    2018-05-01

    Full Text Available To realize the practical applications of flexible pressure sensors, the high performance (sensitivity and response time as well as more functionalities are highly desired. In this work, we fabricated a piezoresistive pressure sensor based on the micro-structured composites films of multi-walled carbon nanotubes (MWCNTs and poly (dimethylsiloxane (PDMS. In addition, we establish efficient strategies to improve key performance of our pressure sensor. Its sensitivity is improved up to 474.13 kPa−1 by minimizing pressure independent resistance of sensor, and response time is shorten as small as 2 μs by enhancing the elastic modulus of polymer elastomer. Benefiting from the high performance, the functionalities of sensors are successfully extended to the accurate detection of high frequency mechanical vibration (~300 Hz and large range of air pressure (6–101 kPa, both of which are not achieved before.

  1. What You Should Know About High Blood Pressure and Medications

    Science.gov (United States)

    ... Aortic Aneurysm More What You Should Know About High Blood Pressure and Medications Updated:Jan 18,2017 Is medication ... resources . This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  2. How Potassium Can Help Control High Blood Pressure

    Science.gov (United States)

    ... Aneurysm More How Potassium Can Help Control High Blood Pressure Updated:Jan 29,2018 Understanding the heart-healthy ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  3. How High Blood Pressure Can Lead to Stroke

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More How High Blood Pressure Can Lead to Stroke Updated:Jan 29,2018 ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  4. High Blood Pressure and Cold Remedies: Which Are Safe?

    Science.gov (United States)

    ... counter cold remedies safe for people who have high blood pressure? Answers from Sheldon G. Sheps, M.D. Over- ... remedies aren't off-limits if you have high blood pressure, but it's important to make careful choices. Among ...

  5. High pressure discharges in cavities formed by microfabrication techniques

    International Nuclear Information System (INIS)

    Khan, B.A.; Cammack, D.A.; Pinker, R.D.; Racz, J.

    1997-01-01

    High pressure discharges are the basis of small high intensity light sources. In this work, we demonstrate the formation of high pressure discharges, in cavities formed by applying micromachining and integrated circuit techniques to quartz substrates. Cavities containing varying amounts of mercury and argon were fabricated to obtain high pressure discharges. A high pressure mercury discharge was formed in the electrodeless cavities by exciting them with a microwave source, operating at 2.45 GHz and in the electroded cavities by applying a dc voltage. The contraction of the discharge into a high pressure arc was observed. A broad emission spectrum due to self-absorption and collisions between excited atoms and normal atoms, typical of high pressure mercury discharges, was measured. The light output and efficacy increased with increasing pressure. The measured voltage was used to estimate the pressure within the electroded cavities, which is as high as 127 atm for one of the two cavities discussed in this work. Efficacies over 40 lumens per watt were obtained for the electrodeless cavities and over 50 scr(l)m/W for the electroded cavities. copyright 1997 American Institute of Physics

  6. Chronic sleep reduction in adolescents

    NARCIS (Netherlands)

    Dewald-Kaufmann, J.F.

    2012-01-01

    Based on the results of this thesis, it can be concluded that sleep problems and chronic sleep reduction have a high impact on adolescents’ daytime functioning. Additionally, this research shows that gradual sleep extension can improve adolescents’ sleep and especially their chronic sleep reduction.

  7. Impurity trapped excitons under high hydrostatic pressure

    Science.gov (United States)

    Grinberg, Marek

    2013-09-01

    Paper summarizes the results on pressure effect on energies of the 4fn → 4fn and 4fn-15d1 → 4fn transitions as well as influence of pressure on anomalous luminescence in Lnα+ doped oxides and fluorides. A model of impurity trapped exciton (ITE) was developed. Two types of ITE were considered. The first where a hole is localized at the Lnα+ ion (creation of Ln(α+1)+) and an electron is attracted by Coulomb potential at Rydberg-like states and the second where an electron captured at the Lnα+ ion (creation of Ln(α-1)+) and a hole is attracted by Coulomb potential at Rydberg-like states. Paper presents detailed analysis of nonlinear changes of energy of anomalous luminescence of BaxSr1-xF2:Eu2+ (x > 0.3) and LiBaF3:Eu2+, and relate them to ITE-4f65d1 states mixing.

  8. Topographic and sex-related differences in sleep spindles in major depressive disorder: a high-density EEG investigation.

    Science.gov (United States)

    Plante, D T; Goldstein, M R; Landsness, E C; Peterson, M J; Riedner, B A; Ferrarelli, F; Wanger, T; Guokas, J J; Tononi, G; Benca, R M

    2013-03-20

    Sleep spindles are believed to mediate several sleep-related functions including maintaining disconnection from the external environment during sleep, cortical development, and sleep-dependent memory consolidation. Prior studies that have examined sleep spindles in major depressive disorder (MDD) have not demonstrated consistent differences relative to control subjects, which may be due to sex-related variation and limited spatial resolution of spindle detection. Thus, this study sought to characterize sleep spindles in MDD using high-density electroencephalography (hdEEG) to examine the topography of sleep spindles across the cortex in MDD, as well as sex-related variation in spindle topography in the disorder. All-night hdEEG recordings were collected in 30 unipolar MDD participants (19 women) and 30 age and sex-matched controls. Topography of sleep spindle density, amplitude, duration, and integrated spindle activity (ISA) were assessed to determine group differences. Spindle parameters were compared between MDD and controls, including analysis stratified by sex. As a group, MDD subjects demonstrated significant increases in frontal and parietal spindle density and ISA compared to controls. When stratified by sex, MDD women demonstrated increases in frontal and parietal spindle density, amplitude, duration, and ISA; whereas MDD men demonstrated either no differences or decreases in spindle parameters. Given the number of male subjects, this study may be underpowered to detect differences in spindle parameters in male MDD participants. This study demonstrates topographic and sex-related differences in sleep spindles in MDD. Further research is warranted to investigate the role of sleep spindles and sex in the pathophysiology of MDD. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Microstructures define melting of molybdenum at high pressures

    Science.gov (United States)

    Hrubiak, Rostislav; Meng, Yue; Shen, Guoyin

    2017-03-01

    High-pressure melting anchors the phase diagram of a material, revealing the effect of pressure on the breakdown of the ordering of atoms in the solid. An important case is molybdenum, which has long been speculated to undergo an exceptionally steep increase in melting temperature when compressed. On the other hand, previous experiments showed nearly constant melting temperature as a function of pressure, in large discrepancy with theoretical expectations. Here we report a high-slope melting curve in molybdenum by synchrotron X-ray diffraction analysis of crystalline microstructures, generated by heating and subsequently rapidly quenching samples in a laser-heated diamond anvil cell. Distinct microstructural changes, observed at pressures up to 130 gigapascals, appear exclusively after melting, thus offering a reliable melting criterion. In addition, our study reveals a previously unsuspected transition in molybdenum at high pressure and high temperature, which yields highly textured body-centred cubic nanograins above a transition temperature.

  10. High-Pressure Oxygen Generation for Outpost EVA Study

    Science.gov (United States)

    Jeng, Frank F.; Conger, Bruce; Ewert, Michael K.; Anderson, Molly S.

    2009-01-01

    The amount of oxygen consumption for crew extravehicular activity (EVA) in future lunar exploration missions will be significant. Eight technologies to provide high pressure EVA O2 were investigated. They are: high pressure O2 storage, liquid oxygen (LOX) storage followed by vaporization, scavenging LOX from Lander followed by vaporization, LOX delivery followed by sorption compression, water electrolysis followed by compression, stand-alone high pressure water electrolyzer, Environmental Control and Life Support System (ECLSS) and Power Elements sharing a high pressure water electrolyzer, and ECLSS and In-Situ Resource Utilization (ISRU) Elements sharing a high pressure electrolyzer. A trade analysis was conducted comparing launch mass and equivalent system mass (ESM) of the eight technologies in open and closed ECLSS architectures. Technologies considered appropriate for the two architectures were selected and suggested for development.

  11. Regional Patterns of Elevated Alpha and High-Frequency Electroencephalographic Activity during Nonrapid Eye Movement Sleep in Chronic Insomnia: A Pilot Study.

    Science.gov (United States)

    Riedner, Brady A; Goldstein, Michael R; Plante, David T; Rumble, Meredith E; Ferrarelli, Fabio; Tononi, Giulio; Benca, Ruth M

    2016-04-01

    To examine nonrapid eye movement (NREM) sleep in insomnia using high-density electroencephalography (EEG). All-night sleep recordings with 256 channel high-density EEG were analyzed for 8 insomnia subjects (5 females) and 8 sex and age-matched controls without sleep complaints. Spectral analyses were conducted using unpaired t-tests and topographical differences between groups were assessed using statistical non-parametric mapping. Five minute segments of deep NREM sleep were further analyzed using sLORETA cortical source imaging. The initial topographic analysis of all-night NREM sleep EEG revealed that insomnia subjects had more high-frequency EEG activity (> 16 Hz) compared to good sleeping controls and that the difference between groups was widespread across the scalp. In addition, the analysis also showed that there was a more circumscribed difference in theta (4-8 Hz) and alpha (8-12 Hz) power bands between groups. When deep NREM sleep (N3) was examined separately, the high-frequency difference between groups diminished, whereas the higher regional alpha activity in insomnia subjects persisted. Source imaging analysis demonstrated that sensory and sensorimotor cortical areas consistently exhibited elevated levels of alpha activity during deep NREM sleep in insomnia subjects relative to good sleeping controls. These results suggest that even during the deepest stage of sleep, sensory and sensorimotor areas in insomnia subjects may still be relatively active compared to control subjects and to the rest of the sleeping brain. © 2016 Associated Professional Sleep Societies, LLC.

  12. High blood pressure in acute ischemic stroke and clinical outcome.

    Science.gov (United States)

    Manabe, Yasuhiro; Kono, Syoichiro; Tanaka, Tomotaka; Narai, Hisashi; Omori, Nobuhiko

    2009-11-16

    This study aimed to evaluate the prognostic value of acute phase blood pressure in patients with acute ischemic stroke by determining whether or not it contributes to clinical outcome. We studied 515 consecutive patients admitted within the first 48 hours after the onset of ischemic strokes, employing systolic and diastolic blood pressure measurements recorded within 36 hours after admission. High blood pressure was defined when the mean of at least 2 blood pressure measurements was ≥200 mmHg systolic and/or ≥110 mmHg diastolic at 6 to 24 hours after admission or ≥180 mmHg systolic and/or ≥105 mmHg diastolic at 24 to 36 hours after admission. The high blood pressure group was found to include 16% of the patients. Age, sex, diabetes mellitus, hypercholesterolemia, atrial fibrillation, ischemic heart disease, stroke history, carotid artery stenosis, leukoaraiosis, NIH Stroke Scale (NIHSS) on admission and mortality were not significantly correlated with either the high blood pressure or non-high blood pressure group. High blood pressure on admission was significantly associated with a past history of hypertension, kidney disease, the modified Rankin Scale (mRS) on discharge and the length of stay. On logistic regression analysis, with no previous history of hypertension, diabetes mellitus, atrial fibrillation, and kidney disease were independent risk factors associated with the presence of high blood pressure [odds ratio (OR), 1.85 (95% confidence interval (CI): 1.06-3.22), 1.89 (95% CI: 1.11-3.22), and 3.31 (95% CI: 1.36-8.04), respectively]. Multi-organ injury may be presented in acute stroke patients with high blood pressure. Patients with high blood pressure had a poor functional outcome after acute ischemic stroke.

  13. The behavioral and health consequences of sleep deprivation among U.S. high school students: relative deprivation matters.

    Science.gov (United States)

    Meldrum, Ryan Charles; Restivo, Emily

    2014-06-01

    To evaluate whether the strength of the association between sleep deprivation and negative behavioral and health outcomes varies according to the relative amount of sleep deprivation experienced by adolescents. 2011 Youth Risk Behavior Survey data of high school students (N=15,364) were analyzed. Associations were examined on weighted data using logistic regression. Twelve outcomes were examined, ranging from weapon carrying to obesity. The primary independent variable was a self-reported measure of average number of hours slept on school nights. Participants who reported deprivations in sleep were at an increased risk of a number of negative outcomes. However, this varied considerably across different degrees of sleep deprivation. For each of the outcomes considered, those who slept less than 5h were more likely to report negative outcomes (adjusted odds ratios ranging from 1.38 to 2.72; psleeping 8 or more hours. However, less extreme forms of sleep deprivation were, in many instances, unrelated to the outcomes considered. Among U.S. high school students, deficits in sleep are significantly and substantively associated with a variety of negative outcomes, and this association is particularly pronounced for students achieving fewer than 5h of sleep at night. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Restricted use of electronic media, sleep, performance, and mood in high school athletes--a randomized trial.

    Science.gov (United States)

    Harris, Anette; Gundersen, Hilde; Mørk-Andreassen, Pia; Thun, Eirunn; Bjorvatn, Bjørn; Pallesen, Ståle

    2015-12-01

    The study aims to evaluate whether 4 weeks with restricted use of electronic media after 22:00 affects sleep, athletic performance, cognitive performance, and mood in high school athletes. Eighty-five athletes were randomized to either an intervention group (n = 44), who was instructed to not use any electronic media after 22:00, or a control condition (n = 41), where they could act as they preferred in terms of media use. Primary outcomes were sleep habits measured with a sleep diary. Secondary outcomes were (a) physical performance measured with a set of standardized tests (beep test, 20-m linear sprint, chin-up test, hanging sit-ups test, counter movement jump and sit-n-reach test); (b) cognitive performance (response time and response accuracy); and (c) positive and negative affect. Differences between groups were tested with mixed between-within subject analyses of variance. Thirty-five and 40 of the athletes in the intervention and control group, respectively, completed the study. Results showed that restricted use of electronic media after 22:00 did not improve sleep habits, athletic performance, cognitive performance, or mood in a group of high school top athletes with already good sleep habits. However, these findings give us knowledge about sleep habits and performance in this population that is of importance when designing future studies. Copyright © 2015 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.

  15. Radioresistance increase in polymers at high pressures. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Milinchuk, V; KIRJUKHIN, V; KLINSHPONT, E

    1977-06-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibers were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene, 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures.

  16. Protection against high intravascular pressure in giraffe legs

    DEFF Research Database (Denmark)

    Petersen, Karin K; Hørlyck, Arne; Østergaard, Kristine Hovkjær

    2013-01-01

    The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination....... All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure....... revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along...

  17. CARS diagnostics of high pressure discharges

    International Nuclear Information System (INIS)

    Uhlenbusch, J.

    2001-01-01

    After a short description of the principles of the CARS, RECARS and POLCARS techniques and a discussion of setups for CARS experiments some experimental results are summarized. The results concern mainly plasma under atmospheric pressure, in particular the determination of temperature in a CO 2 laser-induced pyrolysis flame burning in a silane-acetylene gas mixture, the measurements of N 2 vibrational and rotational temperatures as well as the electron density by CARS and of an NO minority by POLCARS in an atmospheric microwave discharge, and finally RECARS experiments on indium iodide, Which is present in metal halide discharge lamps. Guided by these examples some problems and difficulties arising when performing CARS measurements are discussed

  18. Development of high pressure pipe scanners

    International Nuclear Information System (INIS)

    Kim, Jae H.; Lee, Jae C.; Moon, Soon S.; Eom, Heung S.; Choi, Yu R.

    1998-12-01

    This report describes an automatic ultrasonic scanning system for pressure pipe welds, which was developed in this project using recent advanced technologies on mobile robot and computer. The system consists of two modules: a robot scanner module which navigates and manipulates scanning devices, and a data acquisition module which generates ultrasonic signal and processes the data from the scanner. The robot has 4 magnetic wheels and 2 -axis manipulator on which ultrasonic transducer attached. The wheeled robot can navigate curved surface such as outer wall of circular pipes. Magnetic wheels were optimally designed through magnetic field analysis. Free surface sensing and line tracking control algorithm were developed and implemented, and the control devices and software can be used in practical inspection works. We expect our system can contribute to reduction of inspection time, performance enhancement, and effective management of inspection results

  19. Influence of continuous positive airway pressure on outcomes of rehabilitation in stroke patients with obstructive sleep apnea.

    Science.gov (United States)

    Ryan, Clodagh M; Bayley, Mark; Green, Robin; Murray, Brian J; Bradley, T Douglas

    2011-04-01

    In stroke patients, obstructive sleep apnea (OSA) is associated with poorer functional outcomes than in those without OSA. We hypothesized that treatment of OSA by continuous positive airway pressure (CPAP) in stroke patients would enhance motor, functional, and neurocognitive recovery. This was a randomized, open label, parallel group trial with blind assessment of outcomes performed in stroke patients with OSA in a stroke rehabilitation unit. Patients were assigned to standard rehabilitation alone (control group) or to CPAP (CPAP group). The primary outcomes were the Canadian Neurological scale, the 6-minute walk test distance, sustained attention response test, and the digit or spatial span-backward. Secondary outcomes included Epworth Sleepiness scale, Stanford Sleepiness scale, Functional Independence measure, Chedoke McMaster Stroke assessment, neurocognitive function, and Beck depression inventory. Tests were performed at baseline and 1 month later. Patients assigned to CPAP (n=22) experienced no adverse events. Regarding primary outcomes, compared to the control group (n=22), the CPAP group experienced improvement in stroke-related impairment (Canadian Neurological scale score, PStroke assessment of upper and lower limb motor recovery test of the leg (P=0.001), and the affective component of depression (P=0.006), but not neurocognitive function. Treatment of OSA by CPAP in stroke patients undergoing rehabilitation improved functional and motor, but not neurocognitive outcomes. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00221065.

  20. [Intraabdominal fat redistribution in long-term continuous positive airway pressure treatment in obstructive sleep apnea patients].

    Science.gov (United States)

    Català, Raquel; Ferré, Raimón; Sangenís, Sandra; Cabré, Anna; Hernández-Flix, Salvador; Masana, Lluís

    2016-06-03

    Obesity is the main risk factor for obstructive sleep apnoea (OSA). The aim was to evaluate the long-term effect of continuous positive airway pressure (CPAP) on intraabdominal fat distribution in OSA patients. Fifty OSA patients with and 35 without CPAP treatment criteria were followed-up for 2 years. Visceral and subcutaneous adipose tissue (VAT and SAT) and preaortic intraabdominal fat (PIF) were assessed by sonography. In the non CPAP treated group, SAT and VAT mean values didn't change, while a significantly PIF growth was observed (55.19 [23.44] vs. 63.45 [23.94] mm, P=.021). In the CPAP treated group, VAT and PIF mean were not changed, while SAT decreased significantly (11.29 [5.69] vs. 10.47 [5.71] mm, P=.012). Long-term CPAP treatment produces intraabdominal fat redistribution and is associated with an anthropometric profile of lower cardiovascular risk in OSA patients. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  1. Effect of Continuous Positive Airway Pressure on Adiponectin in Patients with Obstructive Sleep Apnea: A Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Li-Da Chen

    Full Text Available Obstructive sleep apnea (OSA has been suggested to be associated with low levels of adiponectin. Continuous positive airway pressure (CPAP is the gold standard treatment for OSA; however, previous studies assessing the effect of CPAP on adiponectin in patients with OSA yielded conflicting results. The present meta-analysis was performed to determine whether CPAP therapy could increase adiponectin levels.Two reviewers independently searched PubMed, Cochrane library, Embase and Web of Science before February 2015. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of serum adiponectin was extracted for analysis. Standardized mean difference (SMD was used to analyze the summary estimates for CPAP therapy.Eleven studies involving 240 patients were included in this meta-analysis, including ten observational studies and one randomized controlled study. The meta-analysis showed that there was no change of adiponectin levels before and after CPAP treatment in OSA patients (SMD = 0.059, 95% confidence interval (CI = -0.250 to 0.368, z = 0.37, p = 0.710. Subgroup analyses indicated that the results were not affected by age, baseline body mass index, severity of OSA, CPAP therapy duration, sample size and racial differences.This meta-analysis suggested that CPAP therapy has no impact on adiponectin in OSA patients, without significant changes in body weight. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

  2. Oxidative stress mediated arterial dysfunction in patients with obstructive sleep apnoea and the effect of continuous positive airway pressure treatment

    Directory of Open Access Journals (Sweden)

    Del Ben Maria

    2012-07-01

    Full Text Available Abstract Background Several studies suggest an increase of oxidative stress and a reduction of endothelial function in obstructive sleep apnoea syndrome (OSAS. We assessed the association between OSAS, endothelial dysfunction and oxidative stress. Further aim was to evaluate the effect of nasal continuous positive airway pressure (nCPAP on oxidative stress and arterial dysfunction. Methods We studied 138 consecutive patients with heavy snoring and possible OSAS. Patients underwent unattended overnight home polysomnography. Ten patients with severe OSAS were revaluated after 6 months of nCPAP therapy. To assess oxidative stress in vivo, we measured urinary 8-iso-PGF2α and serum levels of soluble NOX2-derived peptide (sNOX2-dp. Serum levels of nitrite/nitrate (NOx were also determined. Flow-mediated brachial artery dilation (FMD was measured to asses endothelial function. Results Patients with severe OSAS had higher urinary 8-iso-PGF2α (p Conclusions The results of our study indicate that patients with OSAS and cardiometabolic comorbidities have increased oxidative stress and arterial dysfunction that are partially reversed by nCPAP treatment.

  3. The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600)

    Science.gov (United States)

    Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

    2013-01-01

    Background Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Methods Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. Results The Australians’ sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians’ sleep tended to be better than that of the Australians at altitude. Conclusions Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives. PMID:24282197

  4. The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600).

    Science.gov (United States)

    Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

    2013-12-01

    Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. The Australians' sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians' sleep tended to be better than that of the Australians at altitude. Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives.

  5. Various high precision measurements of pressure in atomic energy industry

    International Nuclear Information System (INIS)

    Aritomi, Masanori; Inoue, Akira; Hosoma, Takashi; Tanaka, Izumi; Gabane, Tsunemichi.

    1987-01-01

    As for the pressure measurement in atomic energy industry, it is mostly the measurement using differential pressure transmitters and pressure transmitters for process measurement with the general accuracy of measurement of 0.2 - 0.5 % FS/year. However, recently for the development of nuclear fusion reactors and the establishment of nuclear fuel cycle accompanying new atomic energy technology, there are the needs of the pressure measurement having higher accuracy of 0.01 % FS/year and high resolution, and quartz vibration type pressure sensors appeared. New high accuracy pressure measurement techniques were developed by the advance of data processing and the rationalization of data transmission. As the results, the measurement of the differential pressure of helium-lithium two-phase flow in the cooling system of nuclear fusion reactors, the high accuracy measuring system for the level of plutonium nitrate and other fuel substance in tanks in fuel reprocessing and conversion, the high accuracy measurement of atmospheric pressure and wind velocity in ducts, chimneys and tunnels in nuclear facilities and so on became feasible. The principle and the measured data of quartz vibration type pressure sensors are shown. (Kako, I.)

  6. High-pressure applications in medicine and pharmacology

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jerson L; Foguel, Debora; Suarez, Marisa; Gomes, Andre M O; Oliveira, Andrea C [Centro Nacional de Ressonancia Magnetica Nuclear, Departamento de Bioquimica Medica, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590 (Brazil)

    2004-04-14

    High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic.

  7. High-pressure applications in medicine and pharmacology

    International Nuclear Information System (INIS)

    Silva, Jerson L; Foguel, Debora; Suarez, Marisa; Gomes, Andre M O; Oliveira, Andrea C

    2004-01-01

    High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic

  8. Temperature control for high pressure processes up to 1400 MPa

    International Nuclear Information System (INIS)

    Reineke, K; Mathys, A; Knorr, D; Heinz, V

    2008-01-01

    Pressure- assisted sterilisation is an emerging technology. Hydrostatic high pressure can reduce the thermal load of the product and this allows quality retention in food products. To guarantee the safety of the sterilisation process it is necessary to investigate inactivation kinetics especially of bacterial spores. A significant roll during the inactivation of microorganisms under high pressure has the thermodynamic effect of the adiabatic heating. To analyse the individual effect of pressure and temperature on microorganism inactivation an exact temperature control of the sample to reach ideal adiabatic conditions and isothermal dwell times is necessary. Hence a heating/cooling block for a high pressure unit (Stansted Mini-Food-lab; high pressure capillary with 300 μL sample volume) was constructed. Without temperature control the sample would be cooled down during pressure built up, because of the non-adiabatic heating of the steel made vessel. The heating/cooling block allows an ideal adiabatic heat up and cooling of the pressure vessel during compression and decompression. The high pressure unit has a pressure build-up rate up to 250 MPa s -1 and a maximum pressure of 1400 MPa. Sebacate acid was chosen as pressure transmitting medium because it had no phase shift over the investigate pressure and temperature range. To eliminate the temperature difference between sample and vessel during compression and decompression phase, the mathematical model of the adiabatic heating/cooling of water and sebacate acid was implemented into a computational routine, written in Test Point. The calculated temperature is the setpoint of the PID controller for the heating/cooling block. This software allows an online measurement of the pressure and temperature in the vessel and the temperature at the outer wall of the vessel. The accurate temperature control, including the model of the adiabatic heating opens up the possibility to realise an ideal adiabatic heating and cooling

  9. A novel SOI pressure sensor for high temperature application

    International Nuclear Information System (INIS)

    Li Sainan; Liang Ting; Wang Wei; Hong Yingping; Zheng Tingli; Xiong Jijun

    2015-01-01

    The silicon on insulator (SOI) high temperature pressure sensor is a novel pressure sensor with high-performance and high-quality. A structure of a SOI high-temperature pressure sensor is presented in this paper. The key factors including doping concentration and power are analyzed. The process of the sensor is designed with the critical process parameters set appropriately. The test result at room temperature and high temperature shows that nonlinear error below is 0.1%, and hysteresis is less than 0.5%. High temperature measuring results show that the sensor can be used for from room temperature to 350 °C in harsh environments. It offers a reference for the development of high temperature piezoresistive pressure sensors. (semiconductor devices)

  10. High pressure Moessbauer spectroscopy of perovskite iron oxide

    CERN Document Server

    Nasu, S; Morimoto, S; Kawakami, T; Kuzushita, K; Takano, M

    2003-01-01

    High-pressure sup 5 sup 7 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO sub 3 , CaFeO sub 3 and La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 O sub 3. The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO sub 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

  11. High pressure processing reaches the U.S. market

    International Nuclear Information System (INIS)

    Mermelstein, N.H.

    1997-01-01

    The first food product commercially produced by a U.S. company using high-pressure processing has had successful test market results. High-pressure processing permits food to be preserved by subjecting it to pressures in the range of 60,000-100,000 psi for a short time instead of exposing the food to heat, freezing, chemicals, or irradiation. To produce Classic Guacamole, Avomex of Keller, Texas, uses a batch isostatic press to deactivate the enzymes in the avocado and to kill bacteria, obtaining a refrigerated shelf life of over 30 days. The guacamole is then vacuum packed and processed again. The product undergoes no heat treatment and does not contain preservatives, and the high pressure does not affect its texture, color, or taste. Meanwhile, a continuous system for high-pressure processing of pumpable foods is currently being developed by Flow International of Kent, Washington, and will be used for testing and applications work at Oregon State University

  12. High pressure orthorhombic structure of CuInSe2

    International Nuclear Information System (INIS)

    Bovornratanaraks, T; Saengsuwan, V; Yoodee, K; McMahon, M I; Hejny, C; Ruffolo, D

    2010-01-01

    The structural behaviour of CuInSe 2 under high pressure has been studied up to 53 GPa using angle-dispersive x-ray powder diffraction techniques. The previously reported structural phase transition from its ambient pressure tetragonal structure to a high pressure phase with a NaCl-like cubic structure at 7.6 GPa has been confirmed. On further compression, another structural phase transition is observed at 39 GPa. A full structural study of this high pressure phase has been carried out and the high pressure structure has been identified as orthorhombic with space group Cmcm and lattice parameters a = 4.867(8) A, b = 5.023(8) A and c = 4.980(3) A at 53.2(2) GPa. This phase transition behaviour is similar to those of analogous binary and trinary semiconductors, where the orthorhombic Cmcm structure can also be viewed as a distortion of the cubic NaCl-type structure.

  13. High pressure Moessbauer spectroscopy of perovskite iron oxide

    International Nuclear Information System (INIS)

    Nasu, Saburo; Suenaga, Tomoya; Morimoto, Shotaro; Kawakami, Takateru; Kuzushita, Kaori; Takano, Mikio

    2003-01-01

    High-pressure 57 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO 3 , CaFeO 3 and La 1/3 Sr 2/3 O 3 . The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

  14. Fluorinert as a pressure-transmitting medium for high-pressure diffraction studies

    International Nuclear Information System (INIS)

    Varga, Tamas; Wilkinson, Angus P.; Angel, Ross J.

    2003-01-01

    Fluorinert is a liquid pressure-transmitting medium that is widely used in high-pressure diffraction work. A systematic study of five different fluorinerts was carried out using single-crystal x-ray diffraction in a diamond-anvil cell in order to determine the pressure range over which they provide a hydrostatic stress state to the sample. It was found that none of the fluorinerts studied can be considered hydrostatic above 1.2 GPa, a lower pressure than reported previously

  15. Moessbauer study of phase transitions under high hydrostatic pressures. 1

    International Nuclear Information System (INIS)

    Kapitanov, E.V.; Yakovlev, E.N.

    1979-01-01

    Experimental results of the hydrostatic pressure influence on Moessbauer spectrum parameters are obtained over the pressure range including the area of structural phase transition. A linear increase of the Moessbauer effect probability (recoilless fraction) is accompanied by a linear decrease of the electron density at tin nuclei within the pressure range foregoing the phase transition. The electric resistance and the recoilless fraction of the new phase of Mg 2 Sn are lower, but the electron density at tin nuclei is greater than the initial phase ones. Hydrostatic conditions allow to fix clearly the diphasic transition area and to determine the influence of the pressure on the Moessbauer line position and on the recoilless fraction of the high pressure phase. The phase transition heat Q = 415 cal mol -1 is calculated using recoilless fractions of the high and low pressure phases at 25 kbar. The present results are qualitatively and quantitatively different from the results, obtained at nonhydrostatic conditions. (author)

  16. The effect of high pressure on nitrogen compounds of milk

    International Nuclear Information System (INIS)

    Kielczewska, Katarzyna; Czerniewicz, Maria; Michalak, Joanna; Brandt, Waldemar

    2004-01-01

    The effect of pressurization at different pressures (from 200 to 1000 MPa, at 200 MPa intervals, t const. = 15 min) and periods of time (from 15 to 35 min, at 10 min intervals, p const. = 800 MPa) on the changes of proteins and nitrogen compounds of skimmed milk was studied. The pressurization caused an increase in the amount of soluble casein and denaturation of whey proteins. The level of nonprotein nitrogen compounds and proteoso-peptone nitrogen compounds increased as a result of the high-pressure treatment. These changes increased with an increase in pressure and exposure time. High-pressure treatment considerably affected the changes in the conformation of milk proteins, which was reflected in the changes in the content of proteins sedimenting and an increase in their degree of hydration

  17. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    International Nuclear Information System (INIS)

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  18. High temperature pressure water's blowdown into water. Experimental results

    International Nuclear Information System (INIS)

    Ishida, Toshihisa; Kusunoki, Tsuyoshi; Kasahara, Yoshiyuki; Iida, Hiromasa

    1994-01-01

    The purpose of the present experimental study is to clarify the phenomena in blowdown of high temperature and pressure water in pressure vessel into the containment water for evaluation of design of an advanced marine reactor(MRX). The water blown into the containment water flushed and formed steam jet plume. The steam jet condensed in the water, but some stream penetrated to gas phase of containment and contributed to increase of containment pressure. (author)

  19. Fixed-pressure CPAP versus auto-adjusting CPAP: comparison of efficacy on blood pressure in obstructive sleep apnoea, a randomised clinical trial.

    Science.gov (United States)

    Pépin, J L; Tamisier, R; Baguet, J P; Lepaulle, B; Arbib, F; Arnol, N; Timsit, J F; Lévy, P

    2016-08-01

    Millions of individuals with obstructive sleep apnoea (OSA) are treated by CPAP aimed at reducing blood pressure (BP) and thus cardiovascular risk. However, evidence is scarce concerning the impact of different CPAP modalities on BP evolution. This double-blind, randomised clinical trial of parallel groups of patients with OSA indicated for CPAP treatment compared the efficacy of fixed-pressure CPAP (FP-CPAP) with auto-adjusting CPAP (AutoCPAP) in reducing BP. The primary endpoint was the change in office systolic BP after 4 months. Secondary endpoints included 24 h BP measurements. Patients (322) were randomised to FP-CPAP (n=161) or AutoCPAP (n=161). The mean apnoea+hypopnoea index (AHI) was 43/h (SD, 21); mean age was 57 (SD, 11), with 70% of males; mean body mass index was 31.3 kg/m(2) (SD, 6.6) and median device use was 5.1 h/night. In the intention-to-treat analysis, office systolic blood pressure decreased by 2.2 mm Hg (95% CI -5.8 to 1.4) and 0.4 mm Hg (-4.3 to 3.4) in the FP-CPAP and AutoCPAP group, respectively (group difference: -1.3 mm Hg (95% CI -4.1 to 1.5); p=0.37, adjusted for baseline BP values). 24 h diastolic BP (DBP) decreased by 1.7 mm Hg (95% CI -3.9 to 0.5) and 0.5 mm Hg (95% CI -2.3 to 1.3) in the FP-CPAP and AutoCPAP group, respectively (group difference: -1.4 mm Hg (95% CI -2.7 to -0.01); p=0.048, adjusted for baseline BP values). The result was negative regarding the primary outcome of office BP, while FP-CPAP was more effective in reducing 24 h DBP (a secondary outcome). NCT01090297. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. Obstructive sleep apnea is associated with increased QT corrected interval dispersion: the effects of continuous positive airway pressure.

    Science.gov (United States)

    Bilal, Nagihan; Dikmen, Nursel; Bozkus, Fulsen; Sungur, Aylin; Sarica, Selman; Orhan, Israfil; Samur, Anil

    2017-03-31

    Severe obstructive sleep apnea (OSA) is associated with increased QT corrected interval dispersion (QTcd) and continuous positive airway pressure (CPAP) is thought to improve this arrhythmogenic marker. The aim of the study was to determine the decrease of ratio of cardiovascular risk in patients with obstructive sleep apnea. The study included 65 patients with severe OSA who had an apnea-hypopnea index (AHI) score of >30. Each patient underwent 12-channel electrocardiogram (ECG) monitoring and polysomnography. Patients with an AHI score of <5 were used as the control group. The control group also underwent ECG monitoring and polysomnography testing. The QTcd levels of both groups were calculated. Three months after CPAP treatment, ECG recordings were obtained from the 65 patients with severe OSA again, and their QTcd values were calculated. There were 44 male and 21 female patients with severe OSA syndrome. The age, gender, body mass index, initial saturation, minimum saturation, average saturation, and desaturation index were determined in both groups. The QTc intervals of the OSA patients (62.48±16.29ms) were significantly higher (p=0.001) than those of the control group (29.72±6.30ms). There were statistically significant differences between the QTc values before and after the CPAP treatment, with pretreatment QTc intervals of 62.48±16.29ms and 3-month post-treatment values of 41.42±16.96ms (p=0.001). There was a positive and significant correlation between QTcd periods and the AHI and hypopnea index (HI) in OSA patients (p=0.001; r=0.71; p=0.001; r=0.679, respectively). CPAP treatment reduced the QTcd in patients with severe OSA. In addition, shortening the QTcd periods in patients with severe OSA may reduce their risk of arrhythmias and cardiovascular disease. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.