The application of high-pressure treatment in the reduction of salt levels in reduced-phosphate breakfast sausages.

PubMed

O'Flynn, Claire C; Cruz-Romero, Malco C; Troy, Declan; Mullen, Anne M; Kerry, Joe P

2014-03-01

This study investigated the effects of high pressure (HP) treatment of pork meat before manufacturing sausages with reduced salt levels and compared them to sausages manufactured with untreated meat (control sausages). A 2×5 factorial design was set up incorporating two pressure levels (0 or 150 MPa) and five salt levels (0.5, 1.0, 1.5, 2.0 and 2.5%). Most quality attributes were affected when salt levels were reduced below 1.5%. Fat loss (FL) was (P<0.05) affected by salt level; samples with <1.5% salt had the highest FL. HP treatment increased emulsion stability and reduced cook loss (CL) compared to control sausages. Increased CL was observed when salt was reduced below 2.0%. Salt reduction below 1.5% adversely affected colour, sensory and texture attributes. Independent of salt, HP treatment affected adversely juiciness and cohesiveness while adhesiveness was improved. Overall, there is potential to manufacture sausages maintaining organoleptic and functional properties traditionally associated with sausages using HP treated meat. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modulatory Effect of Inflammation on Blood Pressure Reduction via Therapeutic Lifestyle Change

PubMed Central

Milani, Richard V.; Lavie, Carl J.

2009-01-01

Purpose: Since inflammatory status, as determined by C-reactive protein (CRP) levels, is correlated with many cardiovascular (CV) disease risk factors and major CV events, we sought to determine if median levels of CRP can modulate blood pressure changes as well as other CV risk factors that are typically improved by therapeutic lifestyle changes with formal cardiac rehabilitation and exercise training (CRET) programs. Methods: We retrospectively evaluated CRP status and standard CV risk factors both before and after formal, phase II CRET programs (12 weeks; 36 educational and exercise sessions) in 635 consecutive patients with coronary artery disease after major CV events. Results: The median CRP level at baseline was 3.2 mg/L (range, 0.2–80.1 mg/L; mean, 5.8±8.4 mg/L). After CRET, both the patients with high and those with low CRP concentrations exhibited statistically significant improvements in most CV risk factors when their CRP levels were divided by median levels. However, systolic, diastolic, and mean arterial blood pressure improved in patients with low CRP levels (each by −4%) but did not change significantly in patients with high CRP levels. In multiple regression models, only young age, low CRP levels, and low body mass index were significant independent predictors of improved mean arterial blood pressure after CRET. Conclusions: In contrast to patients with coronary artery disease and low levels of CRP, patients with high baseline CRP levels did not demonstrate significant reductions in blood pressure after therapeutic lifestyle changes via formal CRET programs. PMID:21603441

High-Reynolds-number turbulent-boundary-layer wall-pressure fluctuations with dilute polymer solutions

NASA Astrophysics Data System (ADS)

Elbing, Brian R.; Winkel, Eric S.; Ceccio, Steven L.; Perlin, Marc; Dowling, David R.

2010-08-01

Wall-pressure fluctuations were investigated within a high-Reynolds-number turbulent boundary layer (TBL) modified by the addition of dilute friction-drag-reducing polymer solutions. The experiment was conducted at the U.S. Navy's Large Cavitation Channel on a 12.9 m long flat-plate test model with the surface hydraulically smooth (k+<0.2) and achieving downstream-distance-based Reynolds numbers to 220×106. The polymer (polyethylene oxide) solution was injected into the TBL through a slot in the surface. The primary flow diagnostics were skin-friction drag balances and an array of flush-mounted dynamic pressure transducers 9.8 m from the model leading edge. Parameters varied included the free-stream speed (6.7, 13.4, and 20.2 m s-1) and the injection condition (polymer molecular weight, injection concentration, and volumetric injection flux). The behavior of the pressure spectra, convection velocity, and coherence, regardless of the injection condition, were determined primarily based on the level of drag reduction. Results were divided into two regimes dependent on the level of polymer drag reduction (PDR), nominally separated at a PDR of 40%. The low-PDR regime is characterized by decreasing mean-square pressure fluctuations and increasing convection velocity with increasing drag reduction. This shows that the decrease in the pressure spectra with increasing drag reduction is due in part to the moving of the turbulent structures from the wall. Conversely, with further increases in drag reduction, the high-PDR regime has negligible variation in the mean-squared pressure fluctuations and convection velocity. The convection velocity remains constant at approximately 10% above the baseline-flow convection velocity, which suggests that the turbulent structures no longer move farther from the wall with increasing drag reduction. In light of recent numerical work, the coherence results indicate that in the low-PDR regime, the turbulent structures are being elongated in the streamwise direction and occurring at decreasing frequency. In the high-PDR regime, the rate of occurrence continues to decrease until large-scale coherent turbulent structures are potentially no longer present.

Comparison of effects of high-pressure processing and heat treatment on immunoactivity of bovine milk immunoglobulin G in enriched soymilk under equivalent microbial inactivation levels.

PubMed

Li, Si-Quan; Zhang, Howard Q; Balasubramaniam, V M; Lee, Young-Zoon; Bomser, Joshua A; Schwartz, Steven J; Dunne, C Patrick

2006-02-08

Immunoglobulin-rich foods may provide health benefits to consumers. To extend the refrigerated shelf life of functional foods enriched with bovine immunoglobulin G (IgG), nonthermal alternatives such as high-pressure processing (HPP) may offer advantages to thermal processing for microbial reduction. To evaluate the effects of HPP on the immunoactivity of bovine IgG, a soymilk product enriched with milk protein concentrates, derived from dairy cows that were hyperimmunized with 26 human pathogens, was subjected to HPP or heat treatment. To achieve a 5 log reduction in inoculated Escherichia coli 8739, the HPP or heat treatment requirements were 345 MPa for 4 min at 30 degrees C or for 20 s at 70 degrees C, respectively. To achieve a 5 log reduction in natural flora in the enriched soymilk, the HPP or heat treatments needed were 552 MPa for 4 min at 30 degrees C or for 120 s at 78.2 degrees C, respectively. At equivalent levels for a 5 log reduction in E. coli, HPP and heat treatment caused 25% and no detectable loss in bovine IgG activity, respectively. However, at equivalent levels for a 5 log reduction in natural flora, HPP and heat resulted in 65 and 85% loss of bovine IgG activity, respectively. Results of combined pressure-thermal kinetic studies of bovine milk IgG activity were provided to determine the optimal process conditions to preserve product function.

The reduction of gunshot noise and auditory risk through the use of firearm suppressors and low-velocity ammunition.

PubMed

Murphy, William J; Flamme, Gregory A; Campbell, Adam R; Zechmann, Edward L; Tasko, Stephen M; Lankford, James E; Meinke, Deanna K; Finan, Donald S; Stewart, Michael

2018-02-01

This research assessed the reduction of peak levels, equivalent energy and sound power of firearm suppressors. The first study evaluated the effect of three suppressors at four microphone positions around four firearms. The second study assessed the suppressor-related reduction of sound power with a 3 m hemispherical microphone array for two firearms. The suppressors reduced exposures at the ear between 17 and 24 dB peak sound pressure level and reduced the 8 h equivalent A-weighted energy between 9 and 21 dB depending upon the firearm and ammunition. Noise reductions observed for the instructor's position about a metre behind the shooter were between 20 and 28 dB peak sound pressure level and between 11 and 26 dB L Aeq,8h . Firearm suppressors reduced the measured sound power levels between 2 and 23 dB. Sound power reductions were greater for the low-velocity ammunition than for the same firearms fired with high-velocity ammunition due to the effect of N-waves produced by a supersonic bullet. Firearm suppressors may reduce noise exposure, and the cumulative exposures of suppressed firearms can still present a significant hearing risk. Therefore, firearm users should always wear hearing protection whenever target shooting or hunting.

Harm reduction and law enforcement in Vietnam: influences on street policing

PubMed Central

2012-01-01

Background and rationale The HIV epidemic in Vietnam has from its start been concentrated among injecting drug users. Vietnam instituted the 2006 HIV/AIDS Law which includes comprehensive harm reduction measures, but these are unevenly accepted and inadequately implemented. Ward police are a major determinant of risk for IDUs, required to participate in drug control practices (especially meeting quotas for detention centres) which impede support for harm reduction. We studied influences on ward level police regarding harm reduction in Hanoi to learn how to better target education and structural change. Methods After document review, we interviewed informants from government, NGOs, INGOs, multilateral agencies, and police, using semi-structured guides. Topics covered included perceptions of harm reduction and the police role in drug law enforcement, and harm reduction training and advocacy among police. Results Police perceive conflicting responsibilities, but overwhelmingly see their responsibility as enforcing drug laws, identifying and knowing drug users, and selecting those for compulsory detention. Harm reduction training was very patchy, ward police not being seen as important to it; and understanding of harm reduction was limited, tending to reflect drug control priorities. Justification for methadone was as much crime prevention as HIV prevention. Competing pressures on ward police create much anxiety, with performance measures based around drug control; recourse to detention resolves competing pressures more safely. There is much recognition of the importance of discretion, and much use of it to maintain good social order. Policy dissemination approaches within the law enforcement sector were inconsistent, with little communication about harm reduction programs or approaches, and an unfounded assumption that training at senior levels would naturally reach to the street. Discussion Ward police have not been systematically included in harm reduction advocacy or training strategies to support or operationalise legalised harm reduction interventions. The practices of street police challenge harm reduction policies, entirely understandably given the competing pressures on them. For harm reduction to be effective in Vietnam, it is essential that the ambiguities and contradictions between laws to control HIV and to control drugs be resolved for the street-level police. PMID:22769590

Blood pressure as a therapeutic target in stroke.

PubMed

Armario, Pedro; de la Sierra, Alejandro

2009-01-01

Stroke, as a clinical manifestation of the cardiovascular diseases, is one of the leading causes of death and disability in both developed and developing countries. Hypertension is by far, the most important risk factor for stroke. Epidemiological data indicate that the risk of stroke increases with both systolic and diastolic blood pressure elevation, from levels of 115/75 mmHg. It is also evident that most adults worldwide have values above these limits, thus emphasizing the importance of blood pressure as a risk factor for stroke. Clinical trials of antihypertensive treatment, both in studies that have compared active drugs against placebo or in those comparing different types of drugs have clearly demonstrated a protective effect of blood pressure reduction in the prevention of stroke. The degree of protection is directly related to blood pressure reduction and, the lower the level, the better the prognosis. Although data on secondary stroke prevention are scarcer, studies also seem to indicate that lowering blood pressure with antihypertensive treatment protects against stroke recurrence. At the present moment there is still uncertainty on 2 different aspects regarding the relationship between antihypertensive treatment and stroke. First, the blood pressure management during acute stroke has not adequately investigated in clinical trials. Second, the possibility of a protective role of specific types of antihypertensive drugs beyond blood pressure reduction is a matter of debate. Independently of these unresolved issues, prevention of hypertension development by lifestyle changes and adequate treatment and control to the hypertensive population will be a very effective measure in reducing stroke incidence, stroke recurrence, and stroke mortality.

Long-term administration of pyridostigmine attenuates pressure overload-induced cardiac hypertrophy by inhibiting calcineurin signalling.

PubMed

Lu, Yi; Zhao, Ming; Liu, Jin-Jun; He, Xi; Yu, Xiao-Jiang; Liu, Long-Zhu; Sun, Lei; Chen, Li-Na; Zang, Wei-Jin

2017-09-01

Cardiac hypertrophy is associated with autonomic imbalance, characterized by enhanced sympathetic activity and withdrawal of parasympathetic control. Increased parasympathetic function improves ventricular performance. However, whether pyridostigmine, a reversible acetylcholinesterase inhibitor, can offset cardiac hypertrophy induced by pressure overload remains unclear. Hence, this study aimed to determine whether pyridostigmine can ameliorate pressure overload-induced cardiac hypertrophy and identify the underlying mechanisms. Rats were subjected to either sham or constriction of abdominal aorta surgery and treated with or without pyridostigmine for 8 weeks. Vagal activity and cardiac function were determined using PowerLab. Cardiac hypertrophy was evaluated using various histological stains. Protein markers for cardiac hypertrophy were quantitated by Western blot and immunoprecipitation. Pressure overload resulted in a marked reduction in vagal discharge and a profound increase in cardiac hypertrophy index and cardiac dysfunction. Pyridostigmine increased the acetylcholine levels by inhibiting acetylcholinesterase in rats with pressure overload. Pyridostigmine significantly attenuated cardiac hypertrophy based on reduction in left ventricular weight/body weight, suppression of the levels of atrial natriuretic peptide, brain natriuretic peptide and β-myosin heavy chain, and a reduction in cardiac fibrosis. These effects were accompanied by marked improvement of cardiac function. Additionally, pyridostigmine inhibited the CaN/NFAT3/GATA4 pathway and suppressed Orai1/STIM1 complex formation. In conclusion, pressure overload resulted in cardiac hypertrophy, cardiac dysfunction and a significant reduction in vagal discharge. Pyridostigmine attenuated cardiac hypertrophy and improved cardiac function, which was related to improved cholinergic transmission efficiency (decreased acetylcholinesterase and increased acetylcholine), inhibition of the CaN/NFAT3/GATA4 pathway and suppression of the interaction of Orai1/STIM1. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Studies of experimental hosiery in diabetic neuropathic patients with high foot pressures.

PubMed

Veves, A; Masson, E A; Fernando, D J; Boulton, A J

1990-05-01

High plantar pressures and painless trauma are associated with the development of foot ulcers in diabetic patients. Padded hosiery has been reported to reduce plantar pressures in patients at risk of ulceration. Using the optical pedobarograph we have studied 10 patients who regularly wore experimental padded hosiery for 6 months. The hosiery continued to provide substantial and significant reduction in peak forefoot pressures at 3 months (mean reduction 15.5%, p less than 0.01) and 6 months (17.6%, p less than 0.01), although the level of reduction was less than that seen at baseline (31.3%, p less than 0.05). In addition, commercially available hosiery designed as sportswear has been tested, and compared with experimental hosiery. Although these socks (with high or medium density padding) provided significant pressure reduction versus barefoot (mean 17.4% and 10.4%, p less than 0.01), this was not as great as that seen with experimental hosiery (27%, p less than 0.05). Thus the use of socks designed to reduce pressure stress on diabetic neuropathic feet is effective, and continues to be so for a considerable period of time. Commercially available sports socks may also have a place in the management of the diabetic insensitive foot.

Active Control of Fan Noise: Feasibility Study. Volume 4; Flyover System Noise Studies

NASA Technical Reports Server (NTRS)

Kraft, R. E.; Janardan, B. A.; Gliebe, P. R.; Kontos, G. C.

1996-01-01

An extension of a prior study has been completed to examine the potential reduction of aircraft flyover noise by the method of active noise control (ANC). It is assumed that the ANC system will be designed such that it cancels discrete tones radiating from the engine fan inlet or fan exhaust duct, at least to the extent that they no longer protrude above the surrounding broadband noise levels. Thus, without considering the engineering details of the ANC system design, tone levels am arbitrarily removed from the engine component noise spectrum and the flyover noise EPNL levels are compared with and without the presence of tones. The study was conducted for a range of engine cycles, corresponding to fan pressure ratios of 1.3, 1.45, 1.6, and 1.75. This report is an extension of an effort reported previously. The major conclusions drawn from the prior study, which was restricted to fan pressure ratios of 1.45 and 1.75, are that, for a fan pressure ratio of 1.75, ANC of tones gives about the same suppression as acoustic treatment without ANC. For a fan pressure ratio of 1.45, ANC appears to offer less effectiveness from passive treatment. In the present study, the other two fan pressure ratios are included in a more detailed examination of the benefits of the ANC suppression levels. The key results of this extended study are the following observations: (1) The maximum overall benefit obtained from suppression of BPF alone was 2.5 EPNdB at high fan speeds. The suppression benefit increases with increase in fan pressure ratio (FPR), (2) The maximum overall benefit obtained from suppression of the first three harmonics was 3 EPNdB at high speeds. Suppression benefit increases with increase in FPR, (3) At low FPR, only about 1.0 EPNdB maximum reduction was obtained. Suppression is primarily from reduction of BPF at high FPR values and from the combination of tones at low FPR, (4) The benefit from ANC is about the same as the benefit from passive treatment at fan pressure ratios of 1.75 and 1.60. At the two lower fan pressure ratios, the effectivness of treatment is much greater than that of ANC, and (5) No significant difference in ANC suppression behavior was found from the QCSEE engine database analysis compared to that of the E3 engine database, for the FPR = 1.3 engine cycle. The effects of ANC on EPNL noise reduction are difficult to generalize. It was found that the reduction obtained in any particular case depended upon the frequency of the tones and their shift with rpm, the amount of ANC suppression received by each tone (which depended on its protrusion from the background), and the NOY-value of the tone relative to the NOY-value of other tones and the peak broadband levels, because PNL is determined from the sum of the NOY-values.

Influence of cigarette smoking on human autonomic function

NASA Technical Reports Server (NTRS)

Niedermaier, O. N.; Smith, M. L.; Beightol, L. A.; Zukowska-Grojec, Z.; Goldstein, D. S.; Eckberg, D. L.

1993-01-01

BACKGROUND. Although cigarette smoking is known to lead to widespread augmentation of sympathetic nervous system activity, little is known about the effects of smoking on directly measured human sympathetic activity and its reflex control. METHODS AND RESULTS. We studied the acute effects of smoking two research-grade cigarettes on muscle sympathetic nerve activity and on arterial baroreflex-mediated changes of sympathetic and vagal neural cardiovascular outflows in eight healthy habitual smokers. Measurements were made during frequency-controlled breathing, graded Valsalva maneuvers, and carotid baroreceptor stimulation with ramped sequences of neck pressure and suction. Smoking provoked the following changes: Arterial pressure increased significantly, and RR intervals, RR interval spectral power at the respiratory frequency, and muscle sympathetic nerve activity decreased. Plasma nicotine levels increased significantly, but plasma epinephrine, norepinephrine, and neuropeptide Y levels did not change. Peak sympathetic nerve activity during and systolic pressure overshoots after Valsalva straining increased significantly in proportion to increases of plasma nicotine levels. The average carotid baroreceptor-cardiac reflex relation shifted rightward and downward on arterial pressure and RR interval axes; average gain, operational point, and response range did not change. CONCLUSIONS. In habitual smokers, smoking acutely reduces baseline levels of vagal-cardiac nerve activity and completely resets vagally mediated arterial baroreceptor-cardiac reflex responses. Smoking also reduces muscle sympathetic nerve activity but augments increases of sympathetic activity triggered by brief arterial pressure reductions. This pattern of autonomic changes is likely to influence smokers' responses to acute arterial pressure reductions importantly.

On the Propagation of Plane Acoustic Waves in a Duct With Flexible and Impedance Walls

NASA Technical Reports Server (NTRS)

Frendi, Abdelkader; Vu, Bruce

2003-01-01

This Technical Memorandum (TM) discusses the harmonic and random plane acoustic waves propagating from inside a duct to its surroundings. Various duct surfaces are considered, such as rigid, flexible, and impedance. In addition, the effects of a mean flow are studied when the duct alone is considered. Results show a significant reduction in overall sound pressure levels downstream of the impedance wall for both mean flow and no mean flow cases and for a narrow duct. When a wider duct is used, the overall sound pressure level (OSPL) reduction downstream of the impedance wall is much smaller. In the far field, the directivity is such that the overall sound pressure level is reduced by about 5 decibels (dB) on the side of the impedance wall. When a flexible surface is used, the far field directivity becomes asymmetric with an increase in the OSPL on the side of the flexible surface of about 7 dB.

Blood pressure lowering effect of a pea protein hydrolysate in hypertensive rats and humans.

PubMed

Li, Huan; Prairie, Natalie; Udenigwe, Chibuike C; Adebiyi, Abayomi P; Tappia, Paramjit S; Aukema, Harold M; Jones, Peter J H; Aluko, Rotimi E

2011-09-28

The blood pressure lowering effect of a pea protein hydrolysate (PPH) that contained <3 kDa peptides, isolated by membrane ultrafiltration from the thermolysin digest of pea protein isolate (PPI), was examined using different rat models of hypertension as well as hypertensive human subjects. The PPH showed weak in vitro activities against renin and angiotensin converting enzyme (ACE) with inhibitory activities of 17 and 19%, respectively, at 1 mg/mL test concentration. Oral administration of the PPH to spontaneously hypertensive rats (SHR) at doses of 100 and 200 mg/kg body weight led to a lowering of hourly systolic blood pressure (SBP), with a maximum reduction of 19 mmHg at 4 h. In contrast, orally administered unhydrolyzed PPI had no blood pressure reducing effect in SHR, suggesting that thermolysin hydrolysis may have been responsible for releasing bioactive peptides from the native protein. Oral administration of the PPH to the Han:SPRD-cy rat (a model of chronic kidney disease) over an 8-week period led to 29 and 25 mmHg reductions in SBP and diastolic blood pressure, respectively. The PPH-fed rats had lower plasma levels of angiotensin II, the major vasopressor involved in development of hypertension, but there was no effect on plasma activity or renal mRNA levels of ACE. However, renal expression of renin mRNA levels was reduced by approximately 50% in the PPH-fed rats, suggesting that reduced renin may be responsible for the reduced levels of angiotensin II. In a 3-week randomized double blind placebo-controlled crossover human intervention trial (7 volunteers), significant (p<0.05) reductions (over placebo) in SBP of 5 and 6 mmHg were obtained in the second and third weeks, respectively, for the PPH group. Therefore, thermolysin derived bioactive peptides from PPH reduced blood pressure in hypertensive rats and human subjects, likely via effects on the renal angiotensin system.

The design and development of an automatic control system for the in-duct cancellation of spinning modes of sound. M.S. Thesis

NASA Technical Reports Server (NTRS)

Harrington, W. W.

1973-01-01

The reduction is discussed of the discrete tones generated by jet engines which is essential for jet aircraft to meet present and proposed noise standards. The discrete tones generated by the blades and vanes propagate in the inlet and exhaust duct in the form of spiraling acoustic waves, or spinning modes. The reduction of these spinning modes by the cancellation effect of the combination of two acoustic fields was investigated. The spinning mode synthesizer provided the means for effective study of this noise reduction scheme. Two sets of electrical-acoustical transducers located in an equally-spaced circular array simultaneously generate a specified spinning mode and the cancelling mode. Analysis of the wave equation for the synthesizer established the optimum cancelling array acoustic parameters for maximum sound pressure level reduction. The parameter dependence of the frequency ranges of propagation of single, specified circumferential modes generated by a single array, and of effective cancellation of the modes generated by two arrays, was determined. Substantial sound pressure level reduction was obtained for modes within these limits.

Use of Foam to Reduce Gun Blast Noise Levels.

DTIC Science & Technology

1981-03-01

conclusively demonstrated that aqueous foam can effect significant (greater than 10 dB) reductions in gun muzzle blast peak sound pressure level...can yield large reductions in airblast noise level. In these experiments, the explosive charge was engulfed in aqueous foam such as that used in fire...within the foam was closely controlled. Coniguration "C" was also quite similar exc, -" !iat ab .. _ 1 gallon of aqueous foam , contained in a 1-mil

Enhanced H-mode pedestals with lithium injection in DIII-D

DOE PAGES

Osborne, Thomas H.; Jackson, Gary L.; Yan, Zheng; ...

2015-05-08

Periods of edge localized mode (ELM)-free H-mode with increased pedestal pressure and width were observed in the DIII-D tokamak when density fluctuations localized to the region near the separatrix were present. Injection of a powder of 45 μm diameter lithium particles increased the duration of the enhanced pedestal phases to up to 350 ms, and also increased the likelihood of a transition to the enhanced phase. Lithium injection at a level sufficient for triggering the extended enhanced phases resulted in significant lithium in the plasma core, but carbon and other higher Z impurities as well as radiated power levels weremore » reduced. Recycling of the working deuterium gas appeared unaffected by this level of lithium injection. The ion scale, k θ ρ s ~ 0.1–0.2, density fluctuations propagated in the electron drift direction with f ~ 80 kHz and occurred in bursts every ~1 ms. The fluctuation bursts correlated with plasma loss resulting in a flattening of the pressure profile in a region near the separatrix. This localized flattening 2 allowed higher overall pedestal pressure at the peeling-ballooning stability limit and higher pressure than expected under the EPED model due to reduction of the pressure gradient below the “ballooning critical profile”. Furthermore, reduction of the ion pressure by lithium dilution may contribute to the long ELM-free periods.« less

High sound pressure levels in Bavarian discotheques remain after introduction of voluntary agreements.

PubMed

Twardella, Dorothee; Wellhoefer, Andrea; Brix, Jutta; Fromme, Hermann

2008-01-01

While no legal rules or regulations exist in Germany, voluntary measures were introduced to achieve a reduction of sound pressure levels in discotheques to levels below 100 dB(A). To evaluate the current levels in Bavarian discotheques and to find out whether these voluntary measures ensured compliance with the recommended limits, sound pressure levels were measured in 20 Bavarian discotheques between 11 p.m. and 2 a.m. With respect to the equivalent continuous A-weighted sound pressure level for each 30-minute period (L Aeq,30min ), only 4/20 discotheques remained below the limit of 100 dB(A) in all time periods. Ten discotheques had sound pressure levels below 100 dB(A) for the total measurement period (L Aeq,180min ). None of the evaluated factors (weekday, size, estimated age of attendees, the use of voluntary measures such as participation of disc jockeys in a tutorial, or the availability of a sound level meter for the DJs) was significantly associated with the maximal L Aeq, 30min . Thus, the introduction of voluntary measures was not sufficient to ensure compliance with the recommended limits of sound pressure levels.

Testing the Effects of Helium Pressurant on Thermodynamic Vent System Performance with Liquid Hydrogen

NASA Technical Reports Server (NTRS)

Flachbart, R. H.; Hastings, L. J.; Hedayat, A.; Nelson, S.; Tucker, S.

2006-01-01

In support of the development of a zero gravity pressure control capability for liquid hydrogen, testing was conducted at the Marshall Space Flight Center using the Multipurpose Hydrogen Test Bed (MHTB) to evaluate the effects of helium pressurant on the performance of a spray bar thermodynamic vent system (TVS). Fourteen days of testing was performed in August - September 2005, with an ambient heat leak of about 70-80 watts and tank fill levels of 90%, 50%, and 25%. The TVS successfully controlled the tank pressure within a +/- 3.45 kPa (+/- 0.5 psi) band with various helium concentration levels in the ullage. Relative to pressure control with an "all hydrogen" ullage, the helium presence resulted in 10 to 30 per cent longer pressure reduction durations, depending on the fill level, during the mixing/venting phase of the control cycle. Additionally, the automated control cycle was based on mixing alone for pressure reduction until the pressure versus time slope became positive, at which time the Joule-Thomson vent was opened. Testing was also conducted to evaluate thermodynamic venting without the mixer operating, first with liquid then with vapor at the recirculation line inlet. Although ullage stratification was present, the ullage pressure was successfully controlled without the mixer operating. Thus, if vapor surrounded the pump inlet in a reduced gravity situation, the ullage pressure can still be controlled by venting through the TVS Joule Thomson valve and heat exchanger. It was evident that the spray bar configuration, which extends almost the entire length of the tank, enabled significant thermal energy removal from the ullage even without the mixer operating. Details regarding the test setup and procedures are presented in the paper. 1

Exenatide's effect in reducing weight and glycosylated hemoglobin level in an Arab population with type 2 diabetes.

PubMed

Bashier, Alaaeldin M; Abdelgadir, Elamin I; Khalifa, Azza A; Rashid, Fouzia; Abuelkeir, Sona M; Bachet, Fawzi E

2014-11-01

To determine whether exenatide is effective in reducing weight and glycosylated hemoglobin level (HbA1c), and to investigate its efficacy in improving lipid profile, blood pressure, and creatinine levels in the Arab population. This study was conducted at the Endocrine Unit, Dubai Hospital, Dubai, United Arab Emirates. We retrospectively collected data from patients with type 2 diabetes started on exenatide between November 2011 and February 2012. Data included demographics, clinical, laboratory results, and medications used. A general linear model adjusted by baseline characteristics (weight, HbA1C, age, use of statins, and duration of diabetes) was used to assess changes between baseline and end of trial in HbA1C, weight, low density lipoprotein cholesterol, total cholesterol, triglycerides, creatinine, and blood pressure. After 6 months of treatment with exenatide, the HbA1c decreased by 0.47% (95% confidence level [CI]: -0.01 - 0.95) (p=0.055). Weight reduction was highly significant; 5.6 kg (95% CI: 3.34 - 7.85) (p<0.001). Those reductions remained significant after adjustment for confounding factors. This study showed that weight reduction was highly significant with exenatide. The borderline significance in HbA1c reduction can be attributed to the small sample size. 

Effect of Negative Pressure on Proliferation, Virulence Factor Secretion, Biofilm Formation, and Virulence-Regulated Gene Expression of Pseudomonas aeruginosa In Vitro

PubMed Central

Wang, Guo-Qi; Li, Tong-Tong; Li, Zhi-Rui; Zhang, Li-Cheng

2016-01-01

Objective. To investigate the effect of negative pressure conditions induced by NPWT on P. aeruginosa. Methods. P. aeruginosa was cultured in a Luria–Bertani medium at negative pressure of −125 mmHg for 24 h in the experimental group and at atmospheric pressure in the control group. The diameters of the colonies of P. aeruginosa were measured after 24 h. ELISA kit, orcinol method, and elastin-Congo red assay were used to quantify the virulence factors. Biofilm formation was observed by staining with Alexa Fluor® 647 conjugate of concanavalin A (Con A). Virulence-regulated genes were determined by quantitative RT-PCR. Results. As compared with the control group, growth of P. aeruginosa was inhibited by negative pressure. The colony size under negative pressure was significantly smaller in the experimental group than that in the controls (p < 0.01). Besides, reductions in the total amount of virulence factors were observed in the negative pressure group, including exotoxin A, rhamnolipid, and elastase. RT-PCR results revealed a significant inhibition in the expression level of virulence-regulated genes. Conclusion. Negative pressure could significantly inhibit the growth of P. aeruginosa. It led to a decrease in the virulence factor secretion, biofilm formation, and a reduction in the expression level of virulence-regulated genes. PMID:28074188

A change in paradigm: lowering blood pressure in everyone over a certain age.

PubMed

Law, Malcolm

2012-06-01

Dividing people into 'hypertensives' and 'normotensives' is commonplace but problematic. The relationship between blood pressure and cardiovascular disease is continuous. The Prospective Studies Collaboration analysis shows a continuous straight line dose-response relationship across the entire population down to blood pressure levels of 115 mmHg systolic and 75 mmHg diastolic, the confidence limits on the individual data points being sufficiently narrow to exclude even a minor deviation from a linear relationship. Meta-analysis of randomized controlled trials shows that blood pressure-lowering drugs produce similar proportional reductions in risk of coronary heart disease (CHD) and stroke irrespective of pre-treatment blood pressure, down to levels of 110 mmHg systolic and 70 mmHg diastolic. There are also now sufficient trial data to show a statistically significant risk reduction in 'normotensive' people without known vascular disease on entry. The straight line (log-linear) relationship means that the benefit derived from lowering blood pressure is proportional to existing risk, so the decision on whom to treat with blood pressure-lowering drugs should depend on a person's overall absolute risk irrespective of blood pressure. In primary prevention, basing treatment on age alone rather than overall absolute risk entails little loss of efficacy and may be preferred on the basis of simplicity and avoidance of anxiety in telling people they are at elevated risk.

The Influences of Lamination Angles on the Interior Noise Levels of an Aircraft

NASA Technical Reports Server (NTRS)

Fernholz, Christian M.; Robinson, Jay H.

1996-01-01

The feasibility of reducing the interior noise levels of an aircraft passenger cabin through optimization of the composite lay up of the fuselage is investigated. MSC/NASTRAN, a commercially available finite element code, is used to perform the dynamic analysis and subsequent optimization of the fuselage. The numerical calculation of sensitivity of acoustic pressure to lamination angle is verified using a simple thin, cylindrical shell with point force excitations as noise sources. The thin shell used represents a geometry similar to the fuselage and analytic solutions are available for the cylindrical thin shell equations of motion. Optimization of lamination angle for the reduction of interior noise is performed using a finite element model of an actual aircraft fuselage. The aircraft modeled for this study is the Beech Starship. Point forces simulate the structure borne noise produced by the engines and are applied to the fuselage at the wing mounting locations. These forces are the noise source for the optimization problem. The acoustic pressure response is reduced at a number of points in the fuselage and over a number of frequencies. The objective function is minimized with the constraint that it be larger than the maximum sound pressure level at the response points in the passenger cabin for all excitation frequencies in the range of interest. Results from the study of the fuselage model indicate that a reduction in interior noise levels is possible over a finite frequency range through optimal configuration of the lamination angles in the fuselage. Noise reductions of roughly 4 dB were attained. For frequencies outside the optimization range, the acoustic pressure response may increase after optimization. The effects of changing lamination angle on the overall structural integrity of the airframe are not considered in this study.

Comparison of microbiological loads and physicochemical properties of raw milk treated with single-/multiple-cycle high hydrostatic pressure and ultraviolet-C light

NASA Astrophysics Data System (ADS)

Hu, Guanglan; Zheng, Yuanrong; Wang, Danfeng; Zha, Baoping; Liu, Zhenmin; Deng, Yun

2015-07-01

The effects of ultraviolet-C radiation (UV-C, 11.8 W/m2), single-cycle and multiple-cycle high hydrostatic pressure (HHP at 200, 400 or 600 MPa) on microbial load and physicochemical quality of raw milk were evaluated. Reductions of aerobic plate count (APC) and coliform count (CC) by HHP were more than 99.9% and 98.7%, respectively. Inactivation efficiency of microorganisms increased with pressure level. At the same pressure level, two-cycle treatments caused lower APC, but did not show CC differences compared with single-cycle treatments. Reductions of APC and CC by UV-C were somewhere between 200 MPa and 400/600 MPa. Both HHP and UV-C significantly decreased lightness and increased pH, but did not change soluble solids content and thiobarbituric acid-reactive substances' values. Two 2.5 min cycles of HHP at 600 MPa caused minimum APC and CC, and maximum conductivity. Compared with HHP, UV-C markedly increased protein oxidation and reduced darkening.

Helicopter Noise Reduction Design Trade-Off Study

DTIC Science & Technology

1977-01-01

level, A-weighted sound pressure level, perceived noise level and tone corrected perceived noise level time histories, and are further analyzed to...DATA ---------------------------- 101 10 BASELINE VEHICLE EFFECTIVE PERCEIVED NOISE LEVELS (EPiII.) AND RANGE FOR MAXIMIJM TONE CORRECTED PERCEIVED...and tone corrected perceived noise level (PNLT) units. All noise level calculation methods have been computerized in FORTRAN language for use on the

Metalloproteinase Inhibition Protects against Reductions in Circulating Adrenomedullin during Lead-induced Acute Hypertension.

PubMed

Nascimento, Regina A; Mendes, Gabryella; Possomato-Vieira, Jose S; Gonçalves-Rizzi, Victor Hugo; Kushima, Hélio; Delella, Flavia K; Dias-Junior, Carlos A

2015-06-01

Intoxication with lead (Pb) results in increased blood pressure by mechanisms involving matrix metalloproteinases (MMPs). Recent findings have revealed that MMP type two (MMP-2) seems to cleave vasoactive peptides. This study examined whether MMP-2 and MMP-9 levels/activities increase after acute intoxication with low lead concentrations and whether these changes were associated with increases in blood pressure and circulating endothelin-1 or with reductions in circulating adrenomedullin and calcitonin gene-related peptide (CGRP). Here, we expand previous findings and examine whether doxycycline (a MMPs inhibitor) affects these alterations. Wistar rats received intraperitoneally (i.p.) 1st dose 8 μg/100 g of lead (or sodium) acetate, a subsequent dose of 0.1 μg/100 g to cover daily loss and treatment with doxycycline (30 mg/kg/day) or water by gavage for 7 days. Similar whole-blood lead levels (9 μg/dL) were found in lead-exposed rats treated with either doxycycline or water. Lead-induced increases in systolic blood pressure (from 143 ± 2 to 167 ± 3 mmHg) and gelatin zymography of plasma samples showed that lead increased MMP-9 (but not MMP-2) levels. Both lead-induced increased MMP-9 activity and hypertension were blunted by doxycycline. Doxycycline also prevented lead-induced reductions in circulating adrenomedullin. No significant changes in plasma levels of endothelin-1 or CGRP were found. Lead-induced decreases in nitric oxide markers and antioxidant status were not prevented by doxycycline. In conclusion, acute lead exposure increases blood pressure and MMP-9 activity, which were blunted by doxycycline. These findings suggest that MMP-9 may contribute with lead-induced hypertension by cleaving the vasodilatory peptide adrenomedullin, thereby inhibiting adrenomedullin-dependent lowering of blood pressure. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Evaluation of possible head injuries ensuing a cricket ball impact.

PubMed

Mohotti, Damith; Fernando, P L N; Zaghloul, Amir

2018-05-01

The aim of this research is to study the behaviour of a human head during the event of an impact of a cricket ball. While many recent incidents were reported in relation to head injuries caused by the impact of cricket balls, there is no clear information available in the published literature about the possible threat levels and the protection level of the current protective equipment. This research investigates the effects of an impact of a cricket ball on a human head and the level of protection offered by the existing standard cricket helmet. An experimental program was carried out to measure the localised pressure caused by the impact of standard cricket balls. The balls were directed at a speed of 110 km/h on a 3D printed head model, with and without a standard cricket helmet. Numerical simulations were carried out using advanced finite element package LS-DYNA to validate the experimental results. The experimental and numerical results showed approximately a 60% reduction in the pressure on the head model when the helmet was used. Both frontal and side impact resulted in head acceleration values in the range of 225-250 g at a ball speed of 110 km/h. There was a 36% reduction observed in the peak acceleration of the brain when wearing a helmet. Furthermore, numerical simulations showed a 67% reduction in the force on the skull and a 95% reduction in the skull internal energy when introducing the helmet. (1) Upon impact, high localised pressure could cause concussion for a player without helmet. (2) When a helmet was used, the acceleration of the brain observed in the numerical results was at non-critical levels according to existing standards. (3) A significant increase in the threat levels was observed for a player without helmet, based on force, pressure, acceleration and energy criteria, which resulted in recommending the compulsory use of the cricket helmet. (4) Numerical results showed a good correlation with experimental results and hence, the numerical technique used in this study can be recommended for future applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Infectious Causes of Cholesteatoma and Treatment of Infected Ossicles prior to Reimplantation by Hydrostatic High-Pressure Inactivation

PubMed Central

Hinz, Rebecca

2015-01-01

Chronic inflammation, which is caused by recurrent infections, is one of the factors contributing to the pathogenesis of cholesteatoma. If reimplantation of autologous ossicles after a surgical intervention is intended, inactivation of planktonic bacteria and biofilms is desirable. High hydrostatic pressure treatment is a procedure, which has been used to inactivate cholesteatoma cells on ossicles. Here we discuss the potential inactivating effect of high hydrostatic pressure on microbial pathogens including biofilms. Recent experimental data suggest an incomplete inactivation at a pressure level, which is tolerable for the bone substance of ossicles and results at least in a considerable reduction of pathogen load. Further studies are necessary to access how far this quantitative reduction of pathogens is sufficient to prevent ongoing chronic infections, for example, due to forming of biofilms. PMID:25705686

Evaluation of lung volumes, vital capacity and respiratory muscle strength after cervical, thoracic and lumbar spinal surgery.

PubMed

Oliveira, Marcio Aparecido; Vidotto, Milena Carlos; Nascimento, Oliver Augusto; Almeida, Renato; Santoro, Ilka Lopes; Sperandio, Evandro Fornias; Jardim, José Roberto; Gazzotti, Mariana Rodrigues

2015-01-01

Studies have shown that physiopathological changes to the respiratory system can occur following thoracic and abdominal surgery. Laminectomy is considered to be a peripheral surgical procedure, but it is possible that thoracic spinal surgery exerts a greater influence on lung function. The aim of this study was to evaluate the pulmonary volumes and maximum respiratory pressures of patients undergoing cervical, thoracic or lumbar spinal surgery. Prospective study in a tertiary-level university hospital. Sixty-three patients undergoing laminectomy due to diagnoses of tumors or herniated discs were evaluated. Vital capacity, tidal volume, minute ventilation and maximum respiratory pressures were evaluated preoperatively and on the first and second postoperative days. Possible associations between the respiratory variables and the duration of the operation, surgical diagnosis and smoking status were investigated. Vital capacity and maximum inspiratory pressure presented reductions on the first postoperative day (20.9% and 91.6%, respectively) for thoracic surgery (P = 0.01), and maximum expiratory pressure showed reductions on the first postoperative day in cervical surgery patients (15.3%; P = 0.004). The incidence of pulmonary complications was 3.6%. There were reductions in vital capacity and maximum respiratory pressures during the postoperative period in patients undergoing laminectomy. Surgery in the thoracic region was associated with greater reductions in vital capacity and maximum inspiratory pressure, compared with cervical and lumbar surgery. Thus, surgical manipulation of the thoracic region appears to have more influence on pulmonary function and respiratory muscle action.

Estimating the Effectiveness of Imidacloprid When Used to Suppress Transmission of Tomato spotted wilt orthotospovirus in Commercial Agriculture.

PubMed

Chappell, Thomas M; Kennedy, George G

2018-06-21

Imidacloprid is widely used to manage tomato spotted wilt disease (TSW) in tobacco, tomato, and pepper, caused by Tomato spotted wilt orthotospovirus (TSWV) and spread by the tobacco thrips, Frankliniella fusca Hinds (Thysanoptera: Thripidae). Imidacloprid suppresses transmission of TSWV by reducing probing and feeding by adult thrips on treated plants, thereby reducing the probability of transmission by infectious thrips. Because imidacloprid does not reduce probing and feeding on treated plants to zero, the reduction in transmission probability per viruliferous thrips can be offset by an increase in the number of viruliferous thrips challenging treated plants. A composite of these effects which we call 'pathogen pressure' experienced by plants is a function of thrips population size, the proportion of those thrips that are viruliferous, and the probability that viruliferous thrips successfully inoculate plants. To better understand the relationship between imidacloprid's effect on virus transmission, pathogen pressure, and TSW incidence in tobacco, we modeled TSW incidence as a function of the two most important variables affecting components of pathogen pressure, temperature, and precipitation, and the dependence of imidacloprid's effect on pathogen pressure. A model incorporating imidacloprid's effect as a reduction in pathogen pressure was found to be more descriptive than models incorporating the effect as a reduction in TSW incidence. Results reveal maximum proportional reduction in TSW incidence resulting from imidacloprid use is associated with minimal potential TSW incidence. As pathogen pressure increases, potential TSW incidence approaches 100%, and the benefits of imidacloprid use are highest at intermediate levels of pathogen pressure.

Mechanical suppression: Modern technology applied to an old art. [MK 12 motors

NASA Technical Reports Server (NTRS)

Crockford, W. H.; Durney, T. E.; Scott, D. E.; Condon, J. A.

1980-01-01

Various suppressor configurations were analyzed and evaluated in an effort to reduce combustion instability and improved ballistic reproducibility of the MK 12 motor. A static firing test series of eight field return boosters featured two baseline motor firings with the existing suppressor in each motor, followed by two tests each of two different prototype suppressor designs. Results were analyzed and used to generate the design for the final two firings. Acoustic pressure pulsers were utilized to measure the damping effectiveness of the final design. The reduction in motor vibration and acoustic pressure levels between the baseline tests and the final two improved lightweight tests was significant. The average acceleration level of the motors equipped with flightweight rods was reduced to only 5% of the level in the unmodified motors; the average acoustic pressure level was reduced to 20%; maximum values were reduced to 6% for acceleration and 23% for pressure.

Reduction of the sonic boom level in supersonic aircraft flight by the method of surface cooling

NASA Astrophysics Data System (ADS)

Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

2013-12-01

Based on the analysis of various aspects of creating a supersonic transport aircraft of the second generation, the necessity of developing unconventional active methods of sonic boom level reduction is demonstrated. Surface cooling is shown to exert a significant effect on formation of the disturbed flow structure up to large distances from the body by an example of a supersonic flow around a body of revolution. A method of reducing the intensity of the intermediate shock wave and excess pressure momentum near the body is proposed. This method allows the length of the reduced (by 50%) sonic boom level to be increased and the bow shock wave intensity in the far zone to be reduced by 12%. A possibility of controlling the process of formation of wave structures, such as hanging pressure shocks arising near the aircraft surface, is demonstrated. The action of the cryogenic mechanism is explained.

Evaluation of AHRQ's on-time pressure ulcer prevention program: a facilitator-assisted clinical decision support intervention for nursing homes.

PubMed

Olsho, Lauren E W; Spector, William D; Williams, Christianna S; Rhodes, William; Fink, Rebecca V; Limcangco, Rhona; Hurd, Donna

2014-03-01

Pressure ulcers present serious health and economic consequences for nursing home residents. The Agency for Healthcare Research & Quality, in partnership with the New York State Department of Health, implemented the pressure ulcer module of On-Time Quality Improvement for Long Term Care (On-Time), a clinical decision support intervention to reduce pressure ulcer incidence rates. To evaluate the effectiveness of the On-Time program in reducing the rate of in-house-acquired pressure ulcers among nursing home residents. We employed an interrupted time-series design to identify impacts of 4 core On-Time program components on resident pressure ulcer incidence in 12 New York State nursing homes implementing the intervention (n=3463 residents). The sample was purposively selected to include nursing homes with high baseline prevalence and incidence of pressure ulcers and high motivation to reduce pressure ulcers. Differential timing and sequencing of 4 core On-Time components across intervention nursing homes and units enabled estimation of separate impacts for each component. Inclusion of a nonequivalent comparison group of 13 nursing homes not implementing On-Time (n=2698 residents) accounts for potential mean-reversion bias. Impacts were estimated via a random-effects Poisson model including resident-level and facility-level covariates. We find a large and statistically significant reduction in pressure ulcer incidence associated with the joint implementation of 4 core On-Time components (incidence rate ratio=0.409; P=0.035). Impacts vary with implementation of specific component combinations. On-Time implementation is associated with sizable reductions in pressure ulcer incidence.

Preliminary clinical trial with a new hypotensive, guanabenz, in a group of hypertensive patients.

PubMed

De Ridder, J H; Marchandise, P

1980-01-01

In a small preliminary clinical trial of guanabenz in 16 hypertensives also under treatment with diuretics (hydrochlorothiazide and amiloride), blood pressure was safely and completely controlled in 10 (64%), the criterion for "control" being a reduction to the strict level specified by the Society of Actuaries (130/85 m lambda Hg). The dosage of guanabenz was adjusted upward from 16 mg/day until blood pressure normalized or side effects intervened. The 16 patients accumulated 97 months of guanabenz treatment. The 6 unsuccessful cases included only 2 outright therapeutic failures; the other 4 patients discontinued treatment for various reasons: dry mouth and nausea (with good blood pressure reduction); aggravation of existing depression; or generalized urticaria. The fourth patient discontinued for reasons unknown.

Noise reduction in supersonic jets by nozzle fluidic inserts

NASA Astrophysics Data System (ADS)

Morris, Philip J.; McLaughlin, Dennis K.; Kuo, Ching-Wen

2013-08-01

Professor Philip Doak spent a very productive time as a consultant to the Lockheed-Georgia Company in the early 1970s. The focus of the overall research project was the prediction and reduction of noise from supersonic jets. Now, 40 years on, the present paper describes an innovative methodology and device for the reduction of supersonic jet noise. The goal is the development of a practical active noise reduction technique for low bypass ratio turbofan engines. This method introduces fluidic inserts installed in the divergent wall of a CD nozzle to replace hard-wall corrugation seals, which have been demonstrated to be effective by Seiner (2005) [1]. By altering the configuration and operating conditions of the fluidic inserts, active noise reduction for both mixing and shock noise has been obtained. Substantial noise reductions have been achieved for mixing noise in the maximum noise emission direction and in the forward arc for broadband shock-associated noise. To achieve these reductions (on the order of greater than 4 and 2 dB for the two main components respectively), practically achievable levels of injection mass flow rates have been used. The total injected mass flow rates are less than 4% of the core mass flow rate and the effective operating injection pressure ratio has been maintained at or below the same level as the nozzle pressure ratio of the core flow.

Music improves dopaminergic neurotransmission: demonstration based on the effect of music on blood pressure regulation.

PubMed

Sutoo, Den'etsu; Akiyama, Kayo

2004-08-06

The mechanism by which music modifies brain function is not clear. Clinical findings indicate that music reduces blood pressure in various patients. We investigated the effect of music on blood pressure in spontaneously hypertensive rats (SHR). Previous studies indicated that calcium increases brain dopamine (DA) synthesis through a calmodulin (CaM)-dependent system. Increased DA levels reduce blood pressure in SHR. In this study, we examined the effects of music on this pathway. Systolic blood pressure in SHR was reduced by exposure to Mozart's music (K.205), and the effect vanished when this pathway was inhibited. Exposure to music also significantly increased serum calcium levels and neostriatal DA levels. These results suggest that music leads to increased calcium/CaM-dependent DA synthesis in the brain, thus causing a reduction in blood pressure. Music might regulate and/or affect various brain functions through dopaminergic neurotransmission, and might therefore be effective for rectification of symptoms in various diseases that involve DA dysfunction.

A prospective double-blinded randomized controlled trial comparing systemic stress response in Laparoascopic cholecystectomy between low-pressure and standard-pressure pneumoperitoneum.

PubMed

Shoar, Saeed; Naderan, Mohammad; Ebrahimpour, Hossein; Soroush, Ahmadreza; Nasiri, Shirzad; Movafegh, Ali; Khorgami, Zhamak

2016-04-01

Laparoscopic cholecystectomy (LC) has become the gold-standard treatment for gallstone diseases. However, despite huge reduction in operative injury, systemic stress response remains high. This randomized controlled trial (RCT) aimed to compare systemic stress response between 2 different techniques of CO2 pneumoperitoneum. Trough a prospective, double-blinded RCT, serum levels of cortisol, adrenaline, glucose, and C-reactive protein (CRP) were compared between the two groups consisted of 50 patients undergoing LC under low-pressure and standard-pressure CO2 pneimoperitoneum. A total of fifty patients undergoing LC were equally assigned to 2 groups of twenty five patients. Average age was 48 ± 13.8 years (range, 19-74 years). Operative time was similar between standard-pressure group (47.8 ± 16.8 min) and low-pressure group (53.6 ± 25.1). Moreover, intra-operative IV volume administration and urine output did not differ significantly between the 2 groups (p > 0.05). Although the average heart rate and mean arterial pressure were slightly higher in a standard-pressure group compared with a low-pressure group, serial measurements of these parameters were statistically similar between the 2 groups. Serial changes of serum levels of cortisol, glucose, adrenaline, and CRP were compared between surgery day, postoperative 6-h and 1st postoperative day, which did not differ significantly between the standard-pressure and the low-pressure groups (p > 0.05). Our study did not reveal any alteration in systemic stress response with reduction in intra-abdominal pressure of pneumoperitoneum in LC. RCT REGISTRATION: irct.ir ID: IRCT201110072982N5. Copyright © 2016 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

10 CFR 50.62 - Requirements for reduction of risk from anticipated transients without scram (ATWS) events for...

Code of Federal Regulations, 2010 CFR

2010-01-01

... into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the... minute of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope...

10 CFR 50.62 - Requirements for reduction of risk from anticipated transients without scram (ATWS) events for...

Code of Federal Regulations, 2012 CFR

2012-01-01

... into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the... minute of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope...

10 CFR 50.62 - Requirements for reduction of risk from anticipated transients without scram (ATWS) events for...

Code of Federal Regulations, 2011 CFR

2011-01-01

... into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the... minute of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope...

10 CFR 50.62 - Requirements for reduction of risk from anticipated transients without scram (ATWS) events for...

Code of Federal Regulations, 2013 CFR

2013-01-01

... into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the... minute of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope...

10 CFR 50.62 - Requirements for reduction of risk from anticipated transients without scram (ATWS) events for...

Code of Federal Regulations, 2014 CFR

2014-01-01

... into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the... minute of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope...

Effects of endurance, circuit, and relaxing training on cardiovascular risk factors in hypertensive elderly patients.

PubMed

Venturelli, Massimo; Cè, Emiliano; Limonta, Eloisa; Schena, Federico; Caimi, Barbara; Carugo, Stefano; Veicsteinas, Arsenio; Esposito, Fabio

2015-10-01

Recommendations for prevention of cardiovascular diseases (CVDs) risk factors among older adults highlighted the importance of exercise-based interventions, including endurance training (ET). However, the evidence of efficacy of other interventions based on short-bouts of exercise (circuit training, CT), and the practice of breath-control and meditation (relaxing training, RT) is growing. The aim of this study was to elucidate if CT or RT are equally effective in CVD risk factors reduction compared to ET. To this purpose, in 40 elderly participants, with clinically diagnosed grade 1 hypertension, resting blood pressure, blood glucose, and cholesterol levels, peak oxygen uptake ([Formula: see text]), mechanical efficiency and quality of life were evaluated before and after 12 weeks of ET, CT, and RT treatments. Resting blood pressure reduced significantly in all groups by ∼11 %. In ET, blood cholesterol levels (-18 %), [Formula: see text] (+8 %), mechanical efficiency (+9 %), and quality of life scores (+36 %) ameliorated. In CT blood glucose levels (-11 %), [Formula: see text] (+7 %) and quality of life scores (+35 %) were bettered. Conversely, in RT, the lower blood pressure went along only with an improvement in the mental component of quality of life (+42 %). ET and CT were both appropriate interventions to reduce CVDs risk factors, because blood pressure reduction was accompanied by decreases in blood glucose and cholesterol levels, increases in [Formula: see text], mechanical efficiency, and quality of life. Although RT influenced only blood pressure and quality of life, this approach would be an attractive alternative for old individuals unable or reluctant to carry out ET or CT.

Does breast-feeding in infancy lower blood pressure in childhood? The Avon Longitudinal Study of Parents and Children (ALSPAC).

PubMed

Martin, Richard M; Ness, Andrew R; Gunnell, David; Emmett, Pauline; Davey Smith, George

2004-03-16

Breast-feeding in infancy has been associated with decreased coronary heart disease mortality, but the underlying mechanisms are unclear. We investigated the association of breast-feeding with blood pressure in a contemporary cohort. In a prospective cohort study (ALSPAC, United Kingdom), a total of 7276 singleton, term infants born in 1991 and 1992 were examined at 7.5 years. Complete data were available for 4763 children. The systolic and diastolic blood pressures of breast-fed children were 1.2 mm Hg lower (95% CI, 0.5 to 1.9) and 0.9 mm Hg lower (0.3 to 1.4), respectively, compared with children who were never breast-fed (models controlled for age, sex, room temperature, and field observer). Blood pressure differences were attenuated but remained statistically significant in fully adjusted models controlling for social, economic, maternal, and anthropometric variables (reduction in systolic blood pressure: 0.8 mm Hg [0.1 to 1.5]; reduction in diastolic blood pressure: 0.6 mm Hg [0.1 to 1.0]). Blood pressure differences were similar whether breast-feeding was partial or exclusive. We examined the effect of breast-feeding duration. In fully adjusted models, there was a 0.2-mm Hg reduction (0.0 to 0.3) in systolic pressure for each 3 months of breast-feeding. Breast-feeding is associated with a lowering of later blood pressure in children born at term. If the association is causal, the wider promotion of breast-feeding is a potential component of the public health strategy to reduce population levels of blood pressure.

Life style as a blood pressure determinant.

PubMed

Staessen, J A; Bieniaszewski, L; Pardaens, K; Petrov, V; Thijs, L; Fagard, R

1996-09-01

In Belgium, an affluent Western European country, participation in sports, alcohol intake, and living in a working class area were identified as the life style factors with the closest associations with the blood pressure level. Obesity was another important blood pressure correlate. Sodium intake, determined from the 24 h urinary output, and smoking were not associated with blood pressure. Controlled intervention studies have proven that weight reduction, endurance training and alcohol abstinence effectively reduce blood pressure. In the light of these intervention studies, the Belgian findings and the published work highlight the potential of preventive strategies aimed at these major life style factors.

[Health and exercise: effects of exercise on high blood pressure].

PubMed

Ikeda, M; Nanri, H; Himeno, E

1993-09-01

Many factors, such as genetic, psychological, environmental, and socioeconomical factors, influence the health of individuals. Recently behavioral risks which cause preventable chronic diseases or premature death have been increasing. These risk factors are mainly due to living habits, such as over-eating, less exercise and psychological stress. Physical activity or fitness is reported to be inversely associated with morbidity and mortality from chronic diseases, such as cardiovascular diseases diabetes mellitus, cancer and so on. Hypertension has also been reported to be associated with low physical fitness in cross-sectional studies. We have so far reported a significant blood pressure reduction in mild hypertensive patients who completed mild intensity exercise training in well controlled studies. Exercise seemed to modify the multiple factors that might participate in raising and maintaining high blood pressure. The mechanisms of lowering blood pressure by exercise training are mainly due to a depletion of blood volume or the reduction of both cardiac output and the sympathetic tone. They were supported by the evidence of increased levels of prostaglandin E, dopamine, taurine, and decreased levels of plasma norepinephrine and endogenous ouavain-like substance. In this article, we have reviewed the physiological and biochemical roles of exercise, the effects of exercise on high blood pressure, and the hypotensive mechanism of mild aerobic exercise hypertensive patients.

Importance of pressure reducing valves (PRVs) in water supply networks.

NASA Astrophysics Data System (ADS)

Signoreti, R. O. S.; Camargo, R. Z.; Canno, L. M.; Pires, M. S. G.; Ribeiro, L. C. L. J.

2016-08-01

Challenged with the high rate of leakage from water supply systems, these managers are committed to identify control mechanisms. In order to standardize and control the pressure Pressure Reducing Valves (VRP) are installed in the supply network, shown to be more effective and provide a faster return for the actual loss control measures. It is known that the control pressure is while controlling the occurrence of leakage. Usually the network is sectored in areas defined by pressure levels according to its topography, once inserted the VRP in the same system will limit the downstream pressure. This work aims to show the importance of VRP as loss reduction for tool.

Bactericide effect of methylene blue associated with low-level laser therapy in Escherichia coli bacteria isolated from pressure ulcers.

PubMed

Gomes, Thais Ferreira; Pedrosa, Matheus Masalskiene; de Toledo, Ana Claudia Laforga; Arnoni, Veridiana Wanshi; Dos Santos Monteiro, Mirian; Piai, Davi Cury; Sylvestre, Silvia Helena Zacarias; Ferreira, Bruno

2018-05-09

The present study analyzed the bactericidal effect of methylene blue associated with low-level lasers on Escherichia coli isolated from a pressure ulcer. Microbiological material from a pressure ulcer was isolated using an aseptic swab, and antimicrobial activity was verified using the diffusion disc method. Methylene blue was used at concentrations of 0.001 and 0.005%, and low-level lasers of 670, 830, and 904 nm, with the energy densities of 4, 8, 10, and 14 J/cm 2 , were tested on three plates each and combined with methylene blue of each concentration. In addition, three control plates were used, with each concentration and energy density separated without any interventions. The results were analyzed using the paired sample t test to determine the bactericidal effect of the methylene blue and using the ANOVA test to compare the effects of the energy densities and wavelengths among the low-level laser treatment protocols. The results showed bacterial reduction at wavelengths of 830 and 904 nm and more proliferation in wavelengths of 670 nm. In wavelength of 830 nm, a bacterial reduction was observed in the conditions with 0.001% methylene blue in all energy density utilized, with 0.005% methylene blue in energy density of 10 J/cm 2 , and without methylene blue in energy density at 10 J/cm 2 . And in a wavelength of 904 nm, all condition showed bacterial reduction with or without methylene blue. We concluded that the low-level lasers of 904 and 830 nm have bactericidal effects and at better energy densities (10 and 14 J/cm 2 ).

Attack on centrifugal costs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, P.F.

1986-03-01

The Monsanto Chocolate Bayou plant has had an aggressive and successful energy conservation program. The combined efforts have resulted in a 80% reduction in unit energy consumption compared to 1972. The approach of using system audits to optimize fluid systems was developed. Since most of the fluid movers are centrifugal, the name Centrifugal Savings Task Force was adopted. There are three tools that are particularly valuable in optimizing fluid systems. First, a working level understanding of the Affinity Laws seems a must. In addition, the performance curves for the fluid movers is needed. The last need is accurate system fieldmore » data. Systems effectively managed at the Chocolate Bayou plant were process air improvement, feed-water pressure reduction, combustion air blower turbine speed control, and cooling tower pressure reduction. Optimization of centrifugal systems is an often-overlooked opportunity for energy savings. The basic guidelines are to move only the fluid needed, and move it at as low a pressure as possible.« less

Comparison of muzzle suppression and ear-level hearing protection in firearm use.

PubMed

Branch, Matthew Parker

2011-06-01

To compare noise reduction of commercially available ear-level hearing protection (muffs/inserts) to that of firearm muzzle suppressors. Experimental sound measurements under consistent environmental conditions. None. Muzzle suppressors for 2 pistol and 2 rifle calibers were tested using the Bruel & Kjaer 2209 sound meter and Bruel & Kjaer 4136 microphone calibrated with the Bruel & Kjaer Pistonphone using Military-Standard 1474D placement protocol. Five shots were recorded unsuppressed and 10 shots suppressed under consistent environmental conditions. Sound reduction was then compared with the real-world noise reduction rate of the best available ear-level protectors. All suppressors offered significantly greater noise reduction than ear-level protection, usually greater than 50% better. Noise reduction of all ear-level protectors is unable to reduce the impulse pressure below 140 dB for certain common firearms, an international standard for prevention of sensorineural hearing loss. Modern muzzle-level suppression is vastly superior to ear-level protection and the only available form of suppression capable of making certain sporting arms safe for hearing. The inadequacy of standard hearing protectors with certain common firearms is not recognized by most hearing professionals or their patients and should affect the way hearing professionals counsel patients and the public.

Cholecalciferol administration blunts the systemic renin-angiotensin system in essential hypertensives with hypovitaminosis D.

PubMed

Carrara, Davide; Bernini, Matteo; Bacca, Alessandra; Rugani, Ilaria; Duranti, Emiliano; Virdis, Agostino; Ghiadoni, Lorenzo; Taddei, Stefano; Bernini, Giampaolo

2014-03-01

Vitamin D plasma levels are negatively associated with blood pressure and cardiovascular mortality, and vitamin D supplementation reduces cardiovascular events. Renin-angiotensin system (RAS) suppression may be one of the mechanisms involved. However, there are no interventional prospective studies demonstrating a reduction in circulating RAS components after vitamin D treatment. Fifteen consecutive drug-free patients with essential hypertension and hypovitaminosis D underwent therapy with an oral dose of 25000 I.U. of cholecalciferol once a week for two months, while maintaining a constant-salt diet. In basal conditions and at the end of the study, RAS activity (plasma angiotensinogen, renin, PRA, angiotensin II, aldosterone and urinary angiotensinogen) was investigated, in addition to blood pressure and plasma vitamin D levels (25(OH)D). After cholecalciferol administration, all patients exhibited normalized plasma 25(OH)D values. At the end of the study, a reduction (p < 0.05) in plasma renin and aldosterone, and a decrement, although not significant, of PRA and angiotensin II, was observed. No difference was found in plasma and urinary angiotensinogen or blood pressure values. Our data indicate that in essential hypertensives with hypovitaminosis D, pharmacological correction of vitamin D levels can blunt systemic RAS activity.

Rice Cakes Containing Dietary Fiber Supplemented with or without Artemisia Annua and Gynura Procumbens Merr. Alleviated the Risk Factors of Metabolic Syndrome.

PubMed

Yoon, Na Rae; Yoon, Sun; Lee, Seung-Min

2016-04-01

We investigated whether the consumption of Korean rice cakes enriched with dietary fiber with or without polyphenol rich plants might decrease the risk factors of metabolic syndrome (MetS). Rice cakes were manufactured using fructooligosaccharides, resistant starch, and psyllium as sources of dietary fibers with and without polyphenol rich Artemisia annua and Gynura procumbens Merr. (RC+FP and RC+F, respectively), and prepared in three forms (songpyeon, seolgidduk, and chaldduk). Ninety subjects with at least one MetS risk factor were recruited for 6 weeks of dietary intervention. Sixty subjects were finally included for the analysis. Compared to the initial values, RC+FP group had decreased levels of fasting blood glucose (FBG), HOMA-IR and blood pressure after 6 weeks, whereas RC+F group didn't have significant changes in them. Regarding the improvement of individual MetS risk factors, RC+FP group showed significant reduction in FBG and blood pressures but RC+F group only had reduction in systolic blood pressure. After the intervention, a reduction in the number of MetS risk factors was greatert in the RC+FP group than in the RC+F group. In conclusion, Dietary fiber enriched rice cakes with or without polyphenols decreased the number and/or the levels of MetS risk factors. Polyphenol rich plant components may provide additional health benefits in controlling FBG and blood pressure.

Rice Cakes Containing Dietary Fiber Supplemented with or without Artemisia Annua and Gynura Procumbens Merr. Alleviated the Risk Factors of Metabolic Syndrome

PubMed Central

2016-01-01

We investigated whether the consumption of Korean rice cakes enriched with dietary fiber with or without polyphenol rich plants might decrease the risk factors of metabolic syndrome (MetS). Rice cakes were manufactured using fructooligosaccharides, resistant starch, and psyllium as sources of dietary fibers with and without polyphenol rich Artemisia annua and Gynura procumbens Merr. (RC+FP and RC+F, respectively), and prepared in three forms (songpyeon, seolgidduk, and chaldduk). Ninety subjects with at least one MetS risk factor were recruited for 6 weeks of dietary intervention. Sixty subjects were finally included for the analysis. Compared to the initial values, RC+FP group had decreased levels of fasting blood glucose (FBG), HOMA-IR and blood pressure after 6 weeks, whereas RC+F group didn't have significant changes in them. Regarding the improvement of individual MetS risk factors, RC+FP group showed significant reduction in FBG and blood pressures but RC+F group only had reduction in systolic blood pressure. After the intervention, a reduction in the number of MetS risk factors was greatert in the RC+FP group than in the RC+F group. In conclusion, Dietary fiber enriched rice cakes with or without polyphenols decreased the number and/or the levels of MetS risk factors. Polyphenol rich plant components may provide additional health benefits in controlling FBG and blood pressure. PMID:27152297

Cardiopulmonary and arterial baroreceptor unloading during passive hyperthermia does not contribute to hyperthermia-induced hyperventilation

PubMed Central

Lucas, Rebekah A. I.; Pearson, James; Schlader, Zachary J.; Crandall, Craig G.

2016-01-01

This study tested the hypothesis that baroreceptor unloading during passive hyperthermia contributes to increases in ventilation and decreases in end-tidal partial pressure of carbon dioxide (PET,CO2) during that exposure. Two protocols were performed, in which healthy subjects underwent passive hyperthermia (increasing intestinal temperature by ~1.8°C) to cause a sustained increase in ventilation and reduction in PET,CO2. Upon attaining hyperthermic hyperventilation, in protocol 1 (n = 10; three females) a bolus (19 ± 2 ml kg−1) of warm (~38°C) isotonic saline was rapidly (5–10 min) infused intravenously to restore reductions in central venous pressure, whereas in protocol 2 (n = 11; five females) phenylephrine was infused intravenously (60–120 μg min−1) to return mean arterial pressure to normothermic levels. In protocol 1, hyperthermia increased ventilation (by 2.2 ± 1.7 l min−1, P < 0.01), while reducing PET,CO2 (by 4 ± 3 mmHg, P = 0.04) and central venous pressure (by 5 ± 1 mmHg, P <0.01). Saline infusion increased central venous pressure by 5 ± 1 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or PET,CO2 (P > 0.05). In protocol 2, hyperthermia increased ventilation (by 5.0 ± 2.7l min−1, P <0.01) and reduced PET ,CO2 (by 5 ± 2 mmHg, P < 0.01) and mean arterial pressure (by 9 ± 7 mmHg, P <0.01). Phenylephrine infusion increased mean arterial pressure by 12 ± 3 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or PET,CO2 (P > 0.05). The absence of a reduction in ventilation upon reloading the cardiopulmonary and arterial baroreceptors to pre-hyperthermic levels indicates that baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. PMID:26299270

MitoQ administration prevents endotoxin-induced cardiac dysfunction

PubMed Central

Murphy, M. P.; Callahan, L. A.

2009-01-01

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6′-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg·kg−1·day−1), saline + MitoQ (500 μM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction. PMID:19657095

MitoQ administration prevents endotoxin-induced cardiac dysfunction.

PubMed

Supinski, G S; Murphy, M P; Callahan, L A

2009-10-01

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6'-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg x kg(-1) x day(-1)), saline + MitoQ (500 microM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction.

Effect of salt types and concentrations on the high-pressure inactivation of Listeria monocytogenes in ground chicken.

PubMed

Balamurugan, S; Ahmed, Rafath; Chibeu, Andrew; Gao, Anli; Koutchma, Tatiana; Strange, Phil

2016-02-02

National and international health agencies have recommended a significant reduction in daily intake of sodium by reducing the amount of NaCl in foods, specifically processed meats. However, sodium reduction could increase the risk of survival and growth of spoilage and pathogenic microorganisms on these products. Therefore, alternate processing technologies to improve safety of sodium reduced foods are necessary. This study examined the effects of three different salt types and concentrations on high-pressure inactivation of Listeria monocytogenes in pre-blended ground chicken formulations. Ground chicken formulated with three salt types (NaCl, KCl, CaCl2), at three concentrations (0, 1.5, 2.5%) and inoculated with a four strain cocktail of L. monocytogenes (10(8) CFU g(-1)) were subjected to four pressure treatments (0, 100, 300, 600 MPa) and two durations (60, 180 s) in an experiment with factorial design. Surviving cells were enumerated by plating on Oxford agar and analysed by factorial ANOVA. Pressure treatments at 100 or 300 MPa did not significantly (P=0.19-050) reduce L. monocytogenes populations. Neither salt type nor concentration had a significant effect on L. monocytogenes populations at these pressure levels. At 600 MPa, salt types, concentrations and duration of pressure treatment all had a significant effect on L. monocytogenes populations. Formulations with increasing concentrations of NaCl or KCl showed significantly lower reduction in L. monocytogenes, while increase in CaCl2 concentration resulted in a significantly higher L. monocytogenes reduction. For instance, increase in NaCl concentration from 0 to 1.5 or 2.5% resulted in a log reduction of 6.16, 2.49 and 1.29, respectively, when exposed to 600 MPa for 60s. In the case of CaCl2, increase from 0 to 1.5 or 2.5% resulted in a log reduction of 6.16, 7.28 and 7.47, respectively. These results demonstrate that high-pressure processing is a viable process to improve microbial safety of sodium reduced poultry products. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Peripheral Microvascular Responses to Whole-Body Tilting, G(z) Centrifugation, and Lower Body Negative Pressure Stresses in Humans

NASA Technical Reports Server (NTRS)

Breit, G. A.; Watenpaugh, D. E.; Buckley, T. M.; Ballard, R. E.; Murthy, G.; Hargens, A. R.

1994-01-01

The response of the cutaneous microcirculation to orthostatic stress varies along the length of the body due to the interaction of central controls with regional responses to local blood pressure. We hypothesize that artificial orthostatic stresses such as Gz centrifugation and LBNP differ from whole-body tilting in terms of the distribution of microvascular blood flow. Cutaneous microvascular flows were measured by laser Doppler flowmetry at the neck, thigh, and leg of 15 normal subjects. Volunteers underwent stepwise head-up tilt (HUT) and short- and long-arm centrifugation protocols from supine control (0 Gz) to 0.2, 0.4, 0.6, 0.8, 1.0, 0.8, 0.6, 0.4, 0.2, and 0 Gz at the feet, for 30-s periods with 10-s transitions between levels. The same subjects underwent a corresponding supine LBNP protocol, up to 100 mmHg (in 20 mmHg increments) and back to zero pressure, which produced transmural pressure across blood vessels in the foot approximately equal to the HUT protocol. In general, application of all orthostatic stresses produced significant flow reductions in the lower body (p less than 0.05) and inconsistent changes in the neck. At low levels of each stress (0.4 Gz, 40 mmHg), LBNP generated the greatest relative reduction in flow in the lower body (-66.9+/-5.7%, thigh; -60.6 +/-5.7%, leg, mean +/- SE). HUT caused a less severe flow reduction than LBNP at the thigh and leg (-39.9 +/- 8.1% and -55.9+/-4.8%), while the effects induced by both forms of centrifugation were the least profound. Higher levels of each stress generally resulted in similar responses. These responses exhibit a consistent relationship to hypothesized changes in local microvascular transmural pressure, suggesting that myogenic and veno-arteriolar reflexes play a significant role in determining microvascular perfusion during orthostatic stress.

Pressurized chemical-looping combustion of coal with an iron ore-based oxygen carrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Rui; Song, Min; Zhang, Shuai

2010-06-15

Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO{sub 2}. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO{sub 2} sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasifiedmore » with 87.2% steam/N{sub 2} mixture and oxidation with 5% O{sub 2} in N{sub 2} at 970 C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H{sub 2} and CO{sub 2} are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO{sub 2} and lower fractions of CO, CH{sub 4}, and H{sub 2} during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis demonstrates that there is very little coal ash deposited on the oxygen carrier particles but no appreciable crystalline phases change as verified by X-ray diffraction (XRD) analysis. Overall, the limited pressurized CLC experiments carried out in the present work suggest that PCLC of coal is promising and further investigations are necessary. (author)« less

A data base and analysis program for shuttle main engine dynamic pressure measurements

NASA Technical Reports Server (NTRS)

Coffin, T.

1986-01-01

A dynamic pressure data base management system is described for measurements obtained from space shuttle main engine (SSME) hot firing tests. The data were provided in terms of engine power level and rms pressure time histories, and power spectra of the dynamic pressure measurements at selected times during each test. Test measurements and engine locations are defined along with a discussion of data acquisition and reduction procedures. A description of the data base management analysis system is provided and subroutines developed for obtaining selected measurement means, variances, ranges and other statistics of interest are discussed. A summary of pressure spectra obtained at SSME rated power level is provided for reference. Application of the singular value decomposition technique to spectrum interpolation is discussed and isoplots of interpolated spectra are presented to indicate measurement trends with engine power level. Program listings of the data base management and spectrum interpolation software are given. Appendices are included to document all data base measurements.

Energy dissipation in the blade tip region of an axial fan

NASA Astrophysics Data System (ADS)

Bizjan, B.; Milavec, M.; Širok, B.; Trenc, F.; Hočevar, M.

2016-11-01

A study of velocity and pressure fluctuations in the tip clearance flow of an axial fan is presented in this paper. Two different rotor blade tip designs were investigated: the standard one with straight blade tips and the modified one with swept-back tip winglets. Comparison of integral sound parameters indicates a significant noise level reduction for the modified blade tip design. To study the underlying mechanisms of the energy conversion and noise generation, a novel experimental method based on simultaneous measurements of local flow velocity and pressure has also been developed and is presented here. The method is based on the phase space analysis by the use of attractors, which enable more accurate identification and determination of the local flow structures and turbulent flow properties. Specific gap flow energy derived from the pressure and velocity time series was introduced as an additional attractor parameter to assess the flow energy distribution and dissipation within the phase space, and thus determines characteristic sources of the fan acoustic emission. The attractors reveal a more efficient conversion of the pressure to kinetic flow energy in the case of the modified (tip winglet) fan blade design, and also a reduction in emitted noise levels. The findings of the attractor analysis are in a good agreement with integral fan characteristics (efficiency and noise level), while offering a much more accurate and detailed representation of gap flow phenomena.

NOS II inhibition attenuates post-suspension hypotension in Sprague-Dawley rats

NASA Technical Reports Server (NTRS)

Eatman, D.; Walton, M.; Socci, R. R.; Emmett, N.; Bayorh, M. A.

2003-01-01

The reduction in mean arterial pressure observed in astronauts may be related to the impairment of autonomic function and/or excessive production of endothelium-derived relaxing factors. Here, we examined the role of a nitric oxide synthase II (NOS II) inhibitor AMT (2-amino-dihydro-6-methyl-4H-1,3-thiazine) against the post-suspension reduction in mean arterial pressure (MAP) in conscious male Sprague-Dawley rats. Direct MAP and heart rate were determined prior to tail-suspension, daily during the 7-day suspension and every 2 hrs post-suspension. Prior to release from suspension and at 2 and 4 hrs post-suspension, AMT (0.1 mg/kg), or saline, were administered intravenously. During the 7-day suspension, MAP was not altered, nor were there significant changes in heart rate. The reduction in MAP post-suspension in saline-treated rats was associated with significant increases in plasma nitric oxide and prostacyclin. 2-Amino-dihydro-6-methyl4H-1,3-thiazine reduced plasma nitric oxide levels, but not those of prostacyclin, attenuated the observed post-suspension reduction in MAP and modified the baroreflex sensitivity for heart rate. Thus, the post suspension reduction in mean arterial pressure is due, in part, to overproduction of nitric oxide, via the NOS II pathway, and alteration in baroreflex activity.

Impact of Fluidic Chevrons on Jet Noise

NASA Technical Reports Server (NTRS)

Henderson, Brenda S.; Kinzie, Kevin W.; Whitmire, Julia; Abeysinghe, Amal

2005-01-01

The impact of alternating fluidic core chevrons on the production of jet noise is investigated. Core nozzles for a representative 1/9th scale, bypass ratio 5 model system were manufactured with slots cut near the trailing edges to allow for air injection into the core and fan streams. The injectors followed an alternating pattern around the nozzle perimeter so that the injection alternated between injection into the core stream and injection into the fan stream. For the takeoff condition and a forward flight Mach number of 0.10, the overall sound pressure levels at the peak jet noise angle decrease with increasing injection pressure. Sound pressure levels increase for observation angles less than 110o at higher injection pressures due to increases in high frequency noise. Greater increases in high frequency noise are observed when the number of injectors increases from 8 to 12. When the forward flight Mach number is increased to 0.28, jet noise reduction (relative to the baseline) is observed at aft angles for increasing injection pressure while significant increases in jet noise are observed at forward observation angles due to substantial acoustic radiation at high frequencies. A comparison between inflow and alternating injectors shows that, for equal mass injection rates, the inflow nozzle produces greater low frequency noise reduction (relative to the baseline) than the alternating injectors at 90o and aft observation angles and a forward flight Mach number of 0.28. Preliminary computational fluid dynamic simulations indicate that the spatial decay rate of the hot potential core flow is less for the inflow nozzle than for the alternating nozzles which indicates that gentle mixing may be preferred over sever mixing when fluidic chevrons are used for jet noise reduction.

Pathophysiology and implications of intradialytic hypertension.

PubMed

Van Buren, Peter Noel

2017-07-01

Intradialytic hypertension occurs regularly in 10--15% of hemodialysis patients. A large observational study recently showed that intradialytic hypertension of any magnitude increased mortality risk comparable to the most severe degrees of intradialytic hypotension. The present review review discusses the most recent evidence underlying the pathophysiology of intradialytic hypertension and implications for its management. Patients with intradialytic hypertension typically have small interdialytic weight gains, but bioimpedance spectroscopy shows these patients have significant chronic extracellular volume excess. Intradialytic hypertension patients have lower albumin and predialysis urea nitrogen levels, which may contribute to small reductions in osmolarity that prevents blood pressure decreases. Intradialytic vascular resistance surges remain implicated as the driving force for blood pressure increases, but mediators other than endothelin-1 may be responsible. Beyond dry weight reduction, the only controlled intervention shown to interrupt the blood pressure increase is lowering dialysate sodium. Patients with recurrent intradialytic hypertension should be identified as high-risk patients. Dry weight should be re-evaluated, even if patients do not clinically appear volume overloaded. Antihypertensive drugs should be prescribed because of the persistently elevated ambulatory blood pressure. Dialysate sodium reduction should be considered, although the long term effects of this intervention are uncertain.

The Effect of a Coronary Artery Risk Evaluation Program on the Serum Lipid Values of a Selected Military Population

DTIC Science & Technology

1991-05-01

interventions reduced low density lipoproteins and serum cholesterol levels. The goals of risk factor reduction are disease prevention , delay of disease... preventing CAD (Lipid Research Clinics Program, 1984). A 1% reduction in cholesterol was associated with a 2 % reduction in risk (NIH, 1984). This includes...heart attack before age 65? Yes No 2 . Do you have Diabetes Mellitus ? Yes No 3. Do you have uncontrolled hypertension? (Blood Pressure consistently

Hydrodynamic Noise from Flexible Roughness Elements

DTIC Science & Technology

2015-06-29

Virginia Tech (Dr. William Devenport and graduate student Ian Clark) continue to carry out experimental work to test the developed trailing-edge and...work to take into account dynamic motions of the fiber and finite distances between fibers for more realistic aeroacoustic models of its turbulence...pressure levels which result from introduction of the fabric covering. First, Fig. 5 plots the decibel reduction in the experimental surface pressure

'Non-hypotensive' hypovolaemia reduces ascending aortic dimensions in humans

NASA Technical Reports Server (NTRS)

Taylor, J. A.; Halliwill, J. R.; Brown, T. E.; Hayano, J.; Eckberg, D. L.

1995-01-01

1. The notion that small, 'non-hypotensive' reductions of effective blood volume alter neither arterial pressure nor arterial baroreceptor activity is pervasive in the experimental literature. We tested two hypotheses: (a) that minute arterial pressure and cardiac autonomic outflow changes during hypovolaemia induced by lower body suction in humans are masked by alterations in breathing, and (b) that evidence for arterial baroreflex engagement might be obtained from measurements of thoracic aorta dimensions. 2. In two studies, responses to graded lower body suction at 0 (control), 5, 10, 15, 20 and 40 mmHg were examined in twelve and ten healthy young men, respectively. In the first, arterial pressure (photoplethysmograph), R-R interval, and respiratory sinus arrhythmia amplitude (complex demodulation) were measured during uncontrolled and controlled breathing (constant breathing frequency and tidal volume). In the second, cross-sectional areas of the ascending thoracic aorta were calculated from nuclear magnetic resonance images. 3. Lower body suction with controlled breathing resulted in an increased arterial pulse pressure at mild levels (5-20 mmHg; ANOVA, P < 0.05) and a decreased arterial pulse pressure at moderate levels (40 mmHg; ANOVA, P < 0.05). Both R-R intervals and respiratory sinus arrhythmia were negatively related to lower body suction level, whether group averages (general linear regression, r > 0.92) or individual subjects (orthogonal polynomials, 12 of 12 subjects) were assessed. 4. Aortic pulse area decreased progressively and significantly during mild lower body suction, with 47% of the total decline occurring by 5 mmHg. 5. These results suggest that small reductions of effective blood volume reduce aortic baroreceptive areas and trigger haemodynamic adjustments which are so efficient that alterations in arterial pressure escape detection by conventional means.

Method for growth of crystals by pressure reduction of supercritical or subcritical solution

NASA Technical Reports Server (NTRS)

Shlichta, P. J. (Inventor)

1985-01-01

Crystals of high morphological quality are grown by dissolution of a substance to be grown into the crystal in a suitable solvent under high pressure, and by subsequent slow, time-controlled reduction of the pressure of the resulting solution. During the reduction of the pressure interchange of heat between the solution and the environment is minimized by performing the pressure reduction either under isothermal or adiabatic conditions.

Steady-State Plant Model to Predict Hydroden Levels in Power Plant Components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glatzmaier, Greg C.; Cable, Robert; Newmarker, Marc

The National Renewable Energy Laboratory (NREL) and Acciona Energy North America developed a full-plant steady-state computational model that estimates levels of hydrogen in parabolic trough power plant components. The model estimated dissolved hydrogen concentrations in the circulating heat transfer fluid (HTF), and corresponding partial pressures within each component. Additionally for collector field receivers, the model estimated hydrogen pressure in the receiver annuli. The model was developed to estimate long-term equilibrium hydrogen levels in power plant components, and to predict the benefit of hydrogen mitigation strategies for commercial power plants. Specifically, the model predicted reductions in hydrogen levels within the circulatingmore » HTF that result from purging hydrogen from the power plant expansion tanks at a specified target rate. Our model predicted hydrogen partial pressures from 8.3 mbar to 9.6 mbar in the power plant components when no mitigation treatment was employed at the expansion tanks. Hydrogen pressures in the receiver annuli were 8.3 to 8.4 mbar. When hydrogen partial pressure was reduced to 0.001 mbar in the expansion tanks, hydrogen pressures in the receiver annuli fell to a range of 0.001 mbar to 0.02 mbar. When hydrogen partial pressure was reduced to 0.3 mbar in the expansion tanks, hydrogen pressures in the receiver annuli fell to a range of 0.25 mbar to 0.28 mbar. Our results show that controlling hydrogen partial pressure in the expansion tanks allows us to reduce and maintain hydrogen pressures in the receiver annuli to any practical level.« less

A new thermally driven refrigeration system with environmental benefits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garris, C.A. Jr.; Hong, W.J.; Mavriplis, C.

1998-07-01

The pressure-exchange ejector offers the possibility of attaining a breakthrough in the level of performance of ejectors by means of utilizing non-dissipative non-steady flow mechanisms. Yet, the device retains much of the mechanical simplicity of conventional steady-flow ejectors. If such a substantial improvement in performance is demonstrated, its application to ejector refrigeration will be very important. Such a development would provide significant benefits for the environment in terms of both CFC usage reduction and greenhouse gas reduction. The current paper will discuss in detail the concept of pressure-exchange ejector refrigeration, compare it with existing technologies, and discuss the potential impactmore » that might be derived if certain levels of ejector performance can be achieved. Since the limiting issue on the system performance is in the fluid dynamics of non-steady flow induction, research issues and recent progress will be discussed.« less

Experimental and numerical analysis on noise reduction in a multi-blade centrifugal fan

NASA Astrophysics Data System (ADS)

Chen, X. J.; Y Cao, T.; Su, J.; Qin, G. L.

2013-12-01

In this work, analysis on noise source and reduction in a multi-blade centrifugal fan used for air-conditioners was carried out by experimental and numerical methods. Firstly, an experimental system using microphone mounted on volute surface for measuring surface pressure fluctuations of volute was designed and introduced, then surface pressure fluctuations of the whole volute for a multi-blade centrifugal fan were measured by this system, and the inlet noise for this fan was also obtained. And then, based on the experimental results, the aerodynamic noise source of the studied fan was analysed. The surface pressure fluctuations of the volute showed that there were largest surface pressure fluctuations near the volute tongue, and peaks appeared at the Blade Passing Frequency (BPF). The spectra of fan inlet noise showed that the peaks also appeared at BPF, and noise levels in a wide range of frequency were also larger. Secondly, the internal flow of the fan was simulated by commercial software under the same conditions with the experiment, and then the fluid flow and acoustic power field were obtained and discussed. The contours of acoustic power level showed that the larger noise was generated at the impeller area close to the outlet of scroll and at the volute tongue, which is same as that from experiment. Based on all of the results, we can find that the vortex noise is an important part of fan noise for the studied fan, and the rotation noise also cannot be neglected. Finally, several reduction methods that are thought to be effective based on experimental and numerical results were suggested.

Quiet PROPELLER MRI techniques match the quality of conventional PROPELLER brain imaging techniques.

PubMed

Corcuera-Solano, I; Doshi, A; Pawha, P S; Gui, D; Gaddipati, A; Tanenbaum, L

2015-06-01

Switching of magnetic field gradients is the primary source of acoustic noise in MR imaging. Sound pressure levels can run as high as 120 dB, capable of producing physical discomfort and at least temporary hearing loss, mandating hearing protection. New technology has made quieter techniques feasible, which range from as low as 80 dB to nearly silent. The purpose of this study was to evaluate the image quality of new commercially available quiet T2 and quiet FLAIR fast spin-echo PROPELLER acquisitions in comparison with equivalent conventional PROPELLER techniques in current day-to-day practice in imaging of the brain. Thirty-four consecutive patients were prospectively scanned with quiet T2 and quiet T2 FLAIR PROPELLER, in addition to spatial resolution-matched conventional T2 and T2 FLAIR PROPELLER imaging sequences on a clinical 1.5T MR imaging scanner. Measurement of sound pressure levels and qualitative evaluation of relative image quality was performed. Quiet T2 and quiet T2 FLAIR were comparable in image quality with conventional acquisitions, with sound levels of approximately 75 dB, a reduction in average sound pressure levels of up to 28.5 dB, with no significant trade-offs aside from longer scan times. Quiet FSE provides equivalent image quality at comfortable sound pressure levels at the cost of slightly longer scan times. The significant reduction in potentially injurious noise is particularly important in vulnerable populations such as children, the elderly, and the debilitated. Quiet techniques should be considered in these special situations for routine use in clinical practice. © 2015 by American Journal of Neuroradiology.

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry.

PubMed

Holloway, Paul H; Pritchard, David G

2017-08-01

The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (pressure versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. © The Author 2017. Published by Oxford University Press on behalf of Poultry Science Association.

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry

PubMed Central

Holloway, Paul H.; Pritchard, David G.

2017-01-01

Abstract The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (pressure versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. PMID:28521045

Thermodynamic Vent System Performance Testing with Subcooled Liquid Methane and Gaseous Helium Pressurant

NASA Technical Reports Server (NTRS)

Flachbart, R. H.; Hastings, L. J.; Hedayat, A.; Nelson, S. L.; Tucker, S. P.

2007-01-01

Due to its high specific impulse and favorable thermal properties for storage, liquid methane (LCH4) is being considered as a candidate propellant for exploration architectures. In order to gain an -understanding of any unique considerations involving micro-gravity pressure control with LCH4, testing was conducted at the Marshall Space Flight Center using the Multipurpose Hydrogen Test Bed (MHTB) to evaluate the performance of a spray-bar thermodynamic vent system (TVS) with subcooled LCH4 and gaseous helium (GHe) pressurant. Thirteen days of testing were performed in November 2006, with total tank heat leak conditions of about 715 W and 420 W at a fill level of approximately 90%. The TVS system was used to subcool the LCH4 to a liquid saturation pressure of approximately 55.2 kPa before the tank was pressurized with GHe to a total pressure of 165.5 kPa. A total of 23 TVS cycles were completed. The TVS successfully controlled the ullage pressure within a prescribed control band but did not maintain a stable liquid saturation pressure. This was likely. due to a TVS design not optimized for this particular propellant and test conditions, and possibly due to a large artificially induced heat input directly into the liquid. The capability to reduce liquid saturation pressure as well as maintain it within a prescribed control band, demonstrated that the TVS could be used to seek and maintain a desired liquid inlet temperature for an engine (at a cost of propellant lost through the TVS vent). One special test was conducted at the conclusion of the planned test activities. Reduction of the tank ullage pressure by opening the Joule-Thomson valve (JT) without operating the pump was attempted. The JT remained open for over 9300 seconds, resulting in an ullage pressure reduction of 30 kPa. The special test demonstrated the feasibility of using the JT valve for limited ullage pressure reduction in the event of a pump failure.

Diet enriched with fresh coconut decreases blood glucose levels and body weight in normal adults.

PubMed

Vijayakumar, Venugopal; Shankar, Nagashree R; Mavathur, Ramesh; Mooventhan, A; Anju, Sood; Manjunath, N K

2018-02-20

Background There exist controversies about the health effects of coconut. Fresh coconut consumption on human health has not been studied substantially. Fresh coconut consumption is a regular part of the diet for many people in tropical countries like India, and thus there is an increasing need to understand the effects of fresh coconut on various aspects of health. Aim To compare the effects of increased saturated fatty acid (SFA) and fiber intake, provided by fresh coconut, versus monounsaturated fatty acid (MUFA) and fiber intake, provided by a combination of groundnut oil and groundnuts, on anthropometry, serum insulin, glucose levels and blood pressure in healthy adults. Materials Eighty healthy volunteers, randomized into two groups, were provided with a standardized diet along with either 100 g fresh coconut or an equivalent amount of groundnuts and groundnut oil for a period of 90 days. Assessments such as anthropometric measurements, blood pressure, blood sugar and insulin levels were performed before and after the supplementation period. Results Results of this study showed a significant reduction in fasting blood sugar (FBS) in both the groups. However, a significant reduction in body weight was observed in the coconut group, while a significant increase in diastolic pressure was observed in the groundnut group. Conclusions Results of this study suggest that fresh coconut-added diet helps reduce blood glucose levels and body weight in normal healthy individuals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tewari, Somesh Vinayak, E-mail: somesh-vinayak@yahoo.com, E-mail: svtewari@barc.gov.in; Sharma, Archana; Mittal, K. C.

An experimental investigation of surface flashover characteristics of PMMA and POM is studied in compressed nitrogen gas environment with nitrogen as the background gas. The operating pressure range is from 1kg/cm{sup 2} to 4kg/cm{sup 2}. It is observed that the breakdown voltage of PMMA is higher than POM owing to a higher permittivity mismatch between POM- nitrogen interface as compared to the PMMA- nitrogen interface. The reduction in spacer efficiency with pressure for PMMA is 11% as compared to POM which shows a higher reduction of 18%. This paper further emphasizes on the role of energy level and density ofmore » charge carrier trapping centers for a reduced breakdown voltage in POM as compared to PMMA.« less

A person-centered approach to the multifaceted nature of young adult sexual behavior.

PubMed

McGuire, Jenifer K; Barber, Bonnie L

2010-07-01

Young adult sexual relationships were examined using a multifaceted, person-centered approach with data from Wave 7 (aged 20-21; N = 1,126) of the Michigan Study of Adolescent Life Transitions. The study utilized hierarchical cluster analyses based on the following measured variables: frequency of sex, importance of regularly having sex, satisfaction with sex life, experience of coercion for sex, and sexual risk reduction. Five distinct clusters emerged for females (Satisfied, Moderate, Active Unprotected, Pressured, and Inactive) and represented patterns such as more partners paired with less risk reduction (Active Unprotected), high satisfaction paired with frequent sex and high-risk reduction (Satisfied), or higher levels of coercion paired with low satisfaction and low-risk reduction (Pressured). Similar clusters emerged for males, with one additional cluster: the Dissatisfied cluster. Clusters differed with respect to relationship status, marital status, and psychological well-being (both males and females) and parental divorce, living situation, and sexual orientation (females only).

Pressure-reduction and preservation in custom-made footwear of patients with diabetes and a history of plantar ulceration.

PubMed

Waaijman, R; Arts, M L J; Haspels, R; Busch-Westbroek, T E; Nollet, F; Bus, S A

2012-12-01

To assess the value of using in-shoe plantar pressure analysis to improve and preserve the offloading properties of custom-made footwear in patients with diabetes. Dynamic in-shoe plantar pressures were measured in new custom-made footwear of 117 patients with diabetes, neuropathy, and a healed plantar foot ulcer. In 85 of these patients, high peak pressure locations (peak pressure > 200 kPa) were targeted for pressure reduction (goal: > 25% relief or below an absolute level of 200 kPa) by modifying the footwear. After each of a maximum three rounds of modifications, pressures were measured. In a subgroup of 32 patients, pressures were measured and, if needed, footwear was modified at 3-monthly visits for 1 year. Pressures were compared with those measured in 32 control patients who had no footwear modifications based on pressure analysis. At the previous ulcer location and the highest and second highest pressure locations, peak pressures were significantly reduced by 23%, 21% and 15%, respectively, after modification of footwear. These lowered pressures were maintained or further reduced over time and were significantly lower, by 24-28%, compared with pressures in the control group. The offloading capacity of custom-made footwear for high-risk patients can be effectively improved and preserved using in-shoe plantar pressure analysis as guidance tool for footwear modification. This provides a useful approach to obtain better offloading footwear that may reduce the risk for pressure-related diabetic foot ulcers. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

Endpoint design for future renal denervation trials - Novel implications for a new definition of treatment response to renal denervation.

PubMed

Lambert, Thomas; Nahler, Alexander; Rohla, Miklos; Reiter, Christian; Grund, Michael; Kammler, Jürgen; Blessberger, Hermann; Kypta, Alexander; Kellermair, Jörg; Schwarz, Stefan; Starnawski, Jennifer A; Lichtenauer, Michael; Weiss, Thomas W; Huber, Kurt; Steinwender, Clemens

2016-10-01

Defining an adequate endpoint for renal denervation trials represents a major challenge. A high inter-individual and intra-individual variability of blood pressure levels as well as a partial or total non-adherence on antihypertensive drugs hamper treatment evaluations after renal denervation. Blood pressure measurements at a single point in time as used as primary endpoint in most clinical trials on renal denervation, might not be sufficient to discriminate between patients who do or do not respond to renal denervation. We compared the traditional responder classification (defined as systolic 24-hour blood pressure reduction of -5mmHg six months after renal denervation) with a novel definition of an ideal respondership (based on a 24h blood pressure reduction at no point in time, one, or all follow-up timepoints). We were able to re-classify almost a quarter of patients. Blood pressure variability was substantial in patients traditionally defined as responders. On the other hand, our novel classification of an ideal respondership seems to be clinically superior in discriminating sustained from pseudo-response to renal denervation. Based on our observations, we recommend that the traditional response classification should be reconsidered and possibly strengthened by using a composite endpoint of 24h-BP reductions at different follow-up-visits. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Adding a custom made pressure release valve during air enema for intussusception: A new technique.

PubMed

Ahmed, Hosni Morsi; Ahmed, Osama; Ahmed, Refaat Khodary

2015-01-01

Non-surgical reduction remains the first line treatment of choice for intussusception. The major complication of air enema reduction is bowel perforation. The authors developed a custom made pressure release valve to be added to portable insufflation devices, delivering air at pressures accepted as safe for effective reduction of intussusception in children under fluoroscopic guidance. The aim of this study was to develop a custom made pressure release valve that is suitable for the insufflation devices used for air enema reduction of intussusception and to put this valve into regular clinical practice. An adjustable, custom made pressure release valve was assembled by the authors using readily available components. The valve was coupled to a simple air enema insufflation device. The device was used for the trial of reduction of intussusception in a prospective study that included 132 patients. The success rate for air enema reduction with the new device was 88.2%. The mean pressure required to achieve complete reduction was 100 mmHg. The insufflation pressure never exceeded the preset value (120 mmHg). Of the successful cases, 58.3% were reduced from the first attempt while 36.1% required a second insufflation. Only 5.55% required a third insufflation to complete the reduction. In cases with unsuccessful pneumatic reduction attempt (18.1%), surgical treatment was required. Surgery ranged from simple reduction to resection with a primary end to end anastomosis. No complications from air enema were recorded. The authors recommend adding pressure release valves to ensure safety by avoiding pressure overshoot during the procedure.

Characterization of Sodium Mobility and Binding by 23 Na NMR Spectroscopy in a Model Lipoproteic Emulsion Gel for Sodium Reduction.

PubMed

Okada, Kyle S; Lee, Youngsoo

2017-07-01

The effects of formulation and processing parameters on sodium availability in a model lipid/protein-based emulsion gel were studied for purposes of sodium reduction. Heat-set model gels were prepared with varying levels of protein, lipid, and NaCl contents and high pressure homogenization treatments. Single quantum and double quantum-filtered 23 Na NMR spectroscopy experiments were used to characterize sodium mobility, structural order around "bound" (restricted mobility) sodium, and sodium binding, which have been correlated to saltiness perception in food systems previously. Total sodium mobility was lower in gels with higher protein or fat content, and was not affected by changes in homogenization pressure. The gels with increased protein, fat, or homogenization pressure had increased structure surrounding "bound" sodium and more relative "bound" sodium due to increased interfacial protein interactions. The data obtained in this study provide information on factors affecting sodium availability, which can be applied towards sodium reduction in lipid/protein-based foods. © 2017 Institute of Food Technologists®.

Urinary protein as a marker for systolic blood pressure reduction in patients with type 2 diabetes mellitus participating in an in-hospital diabetes education program.

PubMed

Okada, Kenta; Miyamoto, Michiaki; Kotani, Kazuhiko; Yagyu, Hiroaki; Osuga, Junichi; Nagasaka, Shoichiro; Ishibashi, Shun

2011-10-01

Increased blood pressure (BP) and urinary protein (UP)/microalbuminuria are risk factors for cardiovascular disease in patients with diabetes. Although the management of BP in patients with diabetes should involve a multidisciplinary therapy, there are no reports in which modulators have been identified in an in-hospital diabetes education program. The aim of the present study was to investigate the change in BP levels in patients with type 2 diabetes mellitus (T2DM) during a short-term (2-week) in-hospital education program on lifestyle modifications. A total of 167 patients with T2DM (101 men, 66 women; mean age, 61.1 years; glycated hemoglobin, 9.2%) were divided into 2 groups on the basis of their urinary albumin levels: 1 group without UP (urinary albumin level < 30 mg/day) and 1 group with UP (urinary albumin level ≥ 30 mg/day). We defined efficacy in reducing BP as a 20-mm Hg reduction in systolic BP (SBP) and a 10-mm Hg reduction in diastolic BP, and compared the changes between the 2 groups. Although the group with UP had higher SBP levels than the group without UP at baseline, this difference disappeared at the end of the program. Adjusted multivariate logistic regression analysis showed that UP at baseline was associated with a reduction in SBP (odds ratio, 3.361; 95% confidence interval, 1.29-8.79; P = 0.013). The data suggest that UP may be a marker related to the management of SBP through lifestyle modifications in patients with T2DM.

High-pressure insulator-to-metal transition in Sr3Ir2O7 studied by x-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Donnerer, C.; Sala, M. Moretti; Pascarelli, S.; Rosa, A. D.; Andreev, S. N.; Mazurenko, V. V.; Irifune, T.; Hunter, E. C.; Perry, R. S.; McMorrow, D. F.

2018-01-01

High-pressure x-ray absorption spectroscopy was performed at the Ir L3 and L2 absorption edges of Sr3Ir2O7 . The branching ratio of white-line intensities continuously decreases with pressure, reflecting a reduction in the angular part of the expectation value of the spin-orbit coupling operator, 〈L .S 〉 . Up to the high-pressure structural transition at 53 GPa, this behavior can be explained within a single-ion model, where pressure increases the strength of the cubic crystal field, which suppresses the spin-orbit induced hybridization of Jeff=3 /2 and eg levels. We observe a further reduction of the branching ratio above the structural transition, which cannot be explained within a single-ion model of spin-orbit coupling and cubic crystal fields. This change in 〈L .S 〉 in the high-pressure, metallic phase of Sr3Ir2O7 could arise from noncubic crystal fields or a bandwidth-driven hybridization of Jeff=1 /2 ,3 /2 states and suggests that the electronic ground state significantly deviates from the Jeff=1 /2 limit.

Primary water chemistry improvement for radiation exposure reduction at Japanese PWR Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishizawa, Eiichi

1995-03-01

Radiation exposure during the refueling outages at Japanese Pressurized Water Reactor (PWR) Plants has been gradually decreased through continuous efforts keeping the radiation dose rates at relatively low level. The improvement of primary water chemistry in respect to reduction of the radiation sources appears as one of the most important contributions to the achieved results and can be classified by the plant operation conditions as follows

Kidney Mass Reduction Leads to l-Arginine Metabolism-Dependent Blood Pressure Increase in Mice.

PubMed

Pillai, Samyuktha Muralidharan; Seebeck, Petra; Fingerhut, Ralph; Huang, Ji; Ming, Xiu-Fen; Yang, Zhihong; Verrey, François

2018-02-25

Uninephrectomy (UNX) is performed for various reasons, including kidney cancer or donation. Kidneys being the main site of l-arginine production in the body, we tested whether UNX mediated kidney mass reduction impacts l-arginine metabolism and thereby nitric oxide production and blood pressure regulation in mice. In a first series of experiments, we observed a significant increase in arterial blood pressure 8 days post-UNX in female and not in male mice. Further experimental series were performed in female mice, and the blood pressure increase was confirmed by telemetry. l-citrulline, that is used in the kidney to produce l-arginine, was elevated post-UNX as was also asymmetric dimethylarginine, an inhibitor of nitric oxide synthase that competes with l-arginine and is a marker for renal failure. Interestingly, the UNX-induced blood pressure increase was prevented by supplementation of the diet with 5% of the l-arginine precursor, l-citrulline. Because l-arginine is metabolized in the kidney and other peripheral tissues by arginase-2, we tested whether the lack of this metabolic pathway also compensates for decreased l-arginine production in the kidney and/or for local nitric oxide synthase inhibition and consecutive blood pressure increase. Indeed, upon uninephrectomy, arginase-2 knockout mice (Arg-2 -/- ) neither displayed an increase in asymmetric dimethylarginine and l-citrulline plasma levels nor a significant increase in blood pressure. UNX leads to a small increase in blood pressure that is prevented by l-citrulline supplementation or arginase deficiency, 2 measures that appear to compensate for the impact of kidney mass reduction on l-arginine metabolism. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Effects of exercise and excitement on mesenteric and renal dynamics in conscious, unrestrained baboons

NASA Technical Reports Server (NTRS)

Vatner, S. F.

1978-01-01

Radiotelemetry was used to measure arterial pressure and mesenteric and renal blood flows from nine unrestrained, conscious baboons during periods of rest, moderate exercise, and extreme excitement. A description of the experiments hardware is presented, including artificial depressants phenylcyclidine hydrochloride, 0.5-1.0 mg/kg, and pentobarbital sodium, 15 mg/kg, and an ultrasonic telemetry flow meter. Results showed rising heart rate and arterial pressure coupled with a reduction of mesenteric and renal flows as the level of exercise was increased. These findings are compared with mesenteric and renal flows somewhat above control level, but relatively stable heart rate and arterial pressure, postprandially. Attention is given to a quantitative analysis of the experimental results.

The controlling effect of viscous dissipation on magma flow in silicic conduits

USGS Publications Warehouse

Mastin, L.G.

2005-01-01

Nearly all volcanic conduit models assume that flow is Newtonian and isothermal. Such models predict that, during high-flux silicic eruptions, gradients in pressure with depth increase upward as magma accelerates and becomes more viscous, leading to extremely low pressure and fragmentation at a depth of kilometers below the surface. In this paper I show that shear heating, also known as viscous dissipation, dramatically reduces the pressure gradient required for flow and concentrates shear in narrow zones along the conduit margin. The reduction in friction may eliminate the zone of low pressure predicted by isothermal models and move the fragmentation level up to the surface.

[Analysis on the trend of long-term change of blood pressure in hypertensive patients treated with benazepril].

PubMed

Lu, Jun; Li, Li-Ming; He, Ping-Ping; Cao, Wei-Hua; Zhan, Si-Yan; Hu, Yong-Hua

2004-06-01

To introduce the application of mixed linear model in the analysis of secular trend of blood pressure under antihypertensive treatment. A community-based postmarketing surveillance of benazepril was conducted in 1831 essential hypertensive patients (age range from 35 to 88 years) in Shanghai. Data of blood pressure was analyzed every 3 months with mixed linear model to describe the secular trend of blood pressure and changes of age-specific and gender-specific. The changing trends of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were found to fit the curvilinear models. A piecewise model was fit for pulse pressure (PP), i.e., curvilinear model in the first 9 months and linear model after 9 months of taking medication. Both blood pressure and its velocity gradually slowed down. There were significant variation for the curve parameters of intercept, slope, and acceleration. Blood pressure in patients with higher initial levels was persistently declining in the 3-year-treatment. However blood pressures of patients with relatively low initial levels remained low when dropped down to some degree. Elderly patients showed high SBP but low DBP, so as with higher PP. The velocity and sizes of blood pressure reductions increased with the initial level of blood pressure. Mixed linear model is flexible and robust when applied to the analysis of longitudinal data but with missing values and can also make the maximum use of available information.

Pulsed pressure treatment for inactivation of escherichia coli and listeria innocua in whole milk

NASA Astrophysics Data System (ADS)

Buzrul, S.; Largeteau, A.; Alpas, H.; Demazeau, G.

2008-07-01

E. coli and L. innocua in whole milk were subjected to continuous pressure treatments (300, 350, 400, 450, 500, 550 and 600 MPa) at ambient temperature for 5, 10, 15 and 20 min. These treatments underlined that at moderate pressure values (300, 350 and 400 MPa), increasing the pressurization time from 5 to 20 min did not improve cell death to a great extent. Therefore, pulsed pressure treatments (at 300, 350 and 400 MPa) for 5 min (2.5 min × 2 pulses, 1 min × 5 pulses and 0.5 min × 10 pulses), 10 min (5 min × 2 pulses, 2 min × 5 pulses and 1 min × 10 pulses), 15 min (5 min × 3 pulses, 3 min × 5 pulses and 1.5 min × 10 pulses) and 20 min (10 min × 2 pulses, 5 min × 4 pulses, 4 min × 5 pulses and 2 min × 10 pulses) were applied. As already observed in continuous pressure experiments, in pulsed pressure treatments the inactivation level is improved with increasing pressure level and in addition with the number of applied pulses; however, the effect of pulse number is not additive. Results obtained in this study indicated that pulsed pressure treatments could be used to pasteurize the whole milk at lower pressure values than the continuous pressure treatments. Nevertheless, an optimization appears definetely necessary between the number of pulses and pressure levels to reach the desirable number of log-reduction of microorganisms.

[Regression of left heart hypertrophy in arterial hypertension: principles, experimental and clinical findings].

PubMed

Klaus, D

1985-01-01

Left ventricular hypertrophy is the consequence of a structural adaptation of the heart in response to the chronic pressure load, leading to a reduction of the increased systolic wall stress. Studies in spontaneously hypertensive rats have shown, that left ventricular hypertrophy can be influenced by various, but not all antihypertensive agents. Alpha-methyldopa, captopril, beta-blockers and calcium channel blockers resulted in reversal of hypertrophy. Treatment with diuretics, hydralazine or minoxidil did not increase or alter degree of myocardial hypertrophy despite normalization of blood pressure. The biochemical profile after reversal of hypertrophy differs according to antihypertensive therapy, i.e. alpha-methyldopa induces an increase in collagen content, whereas captopril does not alter the collagen content of the myocardium. Adrenergic factors play an important role in modulating the response of the heart. In clinical studies the reduction in cardiac mass does not depend solely on the antihypertensive effect on blood pressure levels. There is only a weak correlation between decrease of left ventricular hypertrophy and fall of blood pressure level, as is shown in 12 patients with essential hypertension, treated with captopril over 6 months. The degree of regression of hypertrophy is influenced by stability of blood pressure control (diurnal variations and response to stress are more important than single casual values), neurohumoral response, presence of associated cardiac diseases, cause and severity of hypertension, genetic factors and age. We studied the regression of left ventricular hypertrophy by M-mode-echocardiography in 12 patients with mild or moderate essential hypertension during a 6-month therapy with captopril (50-75 mg p.d.) and hydrochlorothiazide (50 mg p.d.). In 11 of 12 patients captopril treatment resulted in a reduction of LV-mass of 30.9 +/- 15.1% and wall thickness. Peak systolic and endsystolic wall stress decreased significantly (-29.1% and -27.2%, resp.) after blood pressure reduction, but were still slightly elevated. Ejection fraction increased by 5.4% (p less than or equal to 0.05). 6 hypertensive patients treated for 6 months with metoprolol (150 mg p.d.) and hydrochlorothiazide (50 mg p.d.) do not show significant reduction of LV-mass (-6.5%). Peak and endsystolic wall stress were significantly reduced (-33.1% and -11.5%, resp.) as in captopril therapy. In 34 patients with severe hypertension treated with captopril, hydrochlorothiazide and metoprolol over 30 months, we observed a decline in the Sokolow-Lyon-Index from 4.8 +/- 1.1 mV to 3.8 +/- 0.5 mV after 6 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Moderately high frequency ventilation with a conventional ventilator allows reduction of tidal volume without increasing mean airway pressure.

PubMed

Cordioli, Ricardo Luiz; Park, Marcelo; Costa, Eduardo Leite Vieira; Gomes, Susimeire; Brochard, Laurent; Amato, Marcelo Britto Passos; Azevedo, Luciano Cesar Pontes

2014-12-01

The aim of this study was to explore if positive-pressure ventilation delivered by a conventional ICU ventilator at a moderately high frequency (HFPPV) allows a safe reduction of tidal volume (V T) below 6 mL/kg in a porcine model of severe acute respiratory distress syndrome (ARDS) and at a lower mean airway pressure than high-frequency oscillatory ventilation (HFOV). This is a prospective study. In eight pigs (median weight 34 [29,36] kg), ARDS was induced by pulmonary lavage and injurious ventilation. The animals were ventilated with a randomized sequence of respiratory rates: 30, 60, 90, 120, 150, followed by HFOV at 5 Hz. At each step, V T was adjusted to allow partial pressure of arterial carbon dioxide (PaCO2) to stabilize between 57 and 63 mmHg. Data are shown as median [P25th,P75th]. After lung injury, the PaO2/FiO2 (P/F) ratio was 92 [63,118] mmHg, pulmonary shunt 26 [17,31]%, and static compliance 11 [8,14] mL/cmH2O. Positive end-expiratory pressure (PEEP) was 14 [10,17] cmH2O. At 30 breaths/min, V T was higher than 6 (7.5 [6.8,10.2]) mL/kg, but at all higher frequencies, V T could be reduced and PaCO2 maintained, leading to reductions in plateau pressures and driving pressures. For frequencies of 60 to 150/min, V T progressively fell from 5.2 [5.1,5.9] to 3.8 [3.7,4.2] mL/kg (p < 0.001). There were no detrimental effects in terms of lung mechanics, auto-PEEP generation, hemodynamics, or gas exchange. Mean airway pressure was maintained constant and was increased only during HFOV. During protective mechanical ventilation, HFPPV delivered by a conventional ventilator in a severe ARDS swine model safely allows further tidal volume reductions. This strategy also allowed decreasing airway pressures while maintaining stable PaCO2 levels.

Effect of Sahaja yoga meditation on quality of life, anxiety, and blood pressure control.

PubMed

Chung, Sheng-Chia; Brooks, Maria M; Rai, Madhur; Balk, Judith L; Rai, Sandeep

2012-06-01

The present study investigates the effect of Sahaja yoga meditation on quality of life, anxiety, and blood pressure control. The prospective observational cohort study enrolled two study groups: those receiving treatment from the International Sahaja Yoga Research and Health Center (meditation group) and those receiving treatment from the Mahatma Gandhi Mission Hospital (control group). Researchers measured quality of life, anxiety, and blood pressure before and after treatment. Sixty-seven (67) participants in the meditation group and 62 participants in the control group completed the study. The two groups were comparable in demographic and clinical characteristics. At baseline, the meditation group had higher quality of life (p<0.001) than controls but similar anxiety level (p=0.74) to controls. Within-group pre- versus post-treatment comparisons showed significant improvement in quality of life, anxiety, and blood pressure in the meditation group (p<0.001), while in controls, quality of life deteriorated and there was no improvement in blood pressure. The improvement in quality of life, anxiety reduction, and blood pressure control was greater in the meditation group. The beneficial effect of meditation remained significant after adjusting for confounders. Meditation treatment was associated with significant improvements in quality of life, anxiety reduction, and blood pressure control.

Non-invasive assessment of negative pressure wound therapy using high frequency diagnostic ultrasound: oedema reduction and new tissue accumulation.

PubMed

Young, Stephen R; Hampton, Sylvie; Martin, Robin

2013-08-01

Tissue oedema plays an important role in the pathology of chronic and traumatic wounds. Negative pressure wound therapy (NPWT) is thought to contribute to active oedema reduction, yet few studies have showed this effect. In this study, high frequency diagnostic ultrasound at 20 MHz with an axial resolution of 60 µm was used to assess the effect of NPWT at - 80 mmHg on pressure ulcers and the surrounding tissue. Wounds were monitored in four patients over a 3-month period during which changes in oedema and wound bed thickness (granulation tissue) were measured non-invasively. The results showed a rapid reduction of periwound tissue oedema in all patients with levels falling by a mean of 43% after 4 days of therapy. A 20% increase in the thickness of the wound bed was observed after 7 days due to new granulation tissue formation. Ultrasound scans through the in situ gauze NPWT filler also revealed the existence of macrodeformation in the tissue produced by the negative pressure. These preliminary studies suggest that non-invasive assessment using high frequency diagnostic ultrasound could be a valuable tool in clinical studies of NPWT. © 2012 The Authors. International Wound Journal © 2012 John Wiley & Sons Ltd and Medicalhelplines.com Inc.

Clinical experience in treating hypertension with fixed-dose combination therapy: angiotensin II receptor blocker losartan plus hydrochlorothiazide.

PubMed

Abe, Masanori; Okada, Kazuyoshi; Matsumoto, Koichi

2009-10-01

The goal of antihypertensive treatment is to reduce cardiovascular and cerebrovascular events associated with high blood pressure. A combination therapy with different antihypertensive agents is more successful than monotherapy in most hypertensive patients, with the added advantage of a better safety profile. Therefore, treatment of hypertensive patients with fixed-dose combination therapy consisting of the angiotensin II receptor blocker losartan along with hydrochlorothiazide (HCTZ) has several potential benefits over monotherapy with each individual component. It provides more effective blood pressure control, a reduction in the likelihood of adverse effects and facilitation of patient compliance due to a simple once-daily regimen. One of the advantages of the combination of losartan with HCTZ is the potential reduction in HCTZ-induced metabolic disorders; in particular, this combination can have attractive benefits for patients of hyperuricemia. Losartan plus HCTZ fixed-dose combination therapy is frequently recommended for the treatment of hypertension and lowers blood pressure in mild-to-moderate and even severe hypertensive patients to a level comparable with other classes of antihypertensive agents in combination with HCTZ. Fixed-dose combination therapy with losartan plus HCTZ is a logical choice as antihypertensive therapy for patients in whom combination therapy is necessary to achieve additional blood pressure reduction.

[Assessment of acoustic environment and its effect on hearing in jet engine technical personnel].

PubMed

Konopka, Wiesław; Pawlaczyk-Luszczyńska, Małgorzata; Straszyński, Piotr; Sliwińska-Kowalska, Mariola

2004-01-01

Noise produced by jet engines may be harmful to aircraft servicing personnel because of high levels of acoustic pressure. The aim of the study was to assess the acoustic environment of persons exposed to jet engine noise and its effect on hearing. Noise measurements were performed on three jet engines. During the target practice, the following parameters were measured: equivalent noise, pressure level A, maximum sound pressure level A, and peak sound pressure level C. The spectro-analysis covering the range from 0.1 to 20 kHz was conducted. Hearing was assessed in 50 noise-exposed men, aged 24-51 years (mean age, 35.5 years), using PTA, tympanometry and DPOAE. The control group consisted of 40 non-exposed persons with good hearing condition. Maximum levels of acoustic pressure exceeded Polish standards. Comparison between two groups showed that PTA was higher in the exposed persons by 6.3-6.8 dB on average and DPOAE was reduced in the group exposed to jet engine noise more than it could have been expected. Even during a single test, aircraft technical personnel was exposed to (audible) noise that significantly exceeded admissible values. The reduction in DPOAE values in persons exposed to noise of jet engines was incommensurably higher than changes in PTA.

Factors determining the level and changes in intra-articular pressure in the knee joint of the dog.

PubMed Central

Nade, S; Newbold, P J

1983-01-01

Intra-articular pressure levels were determined for joint positions throughout the normal physiological range of movement of dogs' knee joints. Change in joint position resulted in change in intra-articular pressure. It was demonstrated that intra-articular pressure is highest with the joint in the fully flexed position. Minimum pressure was recorded at a position between 80 degrees and 120 degrees. Minimum pressures were usually subatmospheric. The rate of change of joint position affected intra-articular pressure. The relationship of intra-articular pressure and joint position before and after full flexion demonstrated a hysteresis effect; the pressures were lower than for the same joint position before flexion. Maintenance of the joint in the fully flexed position for increasing periods of time between repeated movement cycles resulted in a similar reduction, of constant magnitude, in pressure between joint positions before and after each period of flexion. However, there was also a progressive decrease in pressure for all joint angles over the total number of movement cycles. There is a contribution to intra-articular pressure of joint capsular compliance and fluid movement into and out of the joint (both of which are time-dependent). The recording of intra-articular pressure in conscious, upright dogs revealed similar pressure levels to those measured in anaesthetized supine dogs. The major determinants of intra-articular pressure in normal dog knee joints include joint size, synovial fluid volume, position of joint, peri-articular tissue and joint anatomy, membrane permeability, capsular compliance, and movement of fluid into and out of the joint. Images Fig. 1 PMID:6875957

HHP treatment of liquid egg at 200-350 MPa

NASA Astrophysics Data System (ADS)

Tóth, A.; Németh, Cs; Palotás, P.; Surányi, J.; Zeke, I.; Csehi, B.; Castillo, L. A.; Friedrich, L.; Balla, Cs

2017-10-01

High hydrostatic pressure (HHP) treatment of egg proteins partially limits their sensitivity to pressure. According to the literature, at the 450 MPa level, denaturation of some proteins sets in to the extent that sensory and functional characteristics are impacted. This study involved treating liquid egg (egg white, yolk, and melange) at less than the above-mentioned value, after which the microbiological effect was examined. For the study, pressure pouches were filled with 100ml of raw liquid egg per pouch. Then the samples were treated at 200, 250, 300 and 350 MPa. In each case, the level was reached by increasing pressure at a rate of 100 MPa/min. Measurements were taken at the Corvinus University of Budapest, Faculty of Food Science, Dept. of Refrigeration and Livestock Products Technology RESATO FPU 100-2000 equipment. Denaturation was determined with calorimetric (DSC) tests. From our results, it appears that even at 250 MPa pressure treatment, the viable cell count decreases. Further, it can be said that microbe count went down in the egg white samples at 300-350 MPa, below the impact level. Significant denaturation was not detected during our examinations. In summary, we state that the most HHP-sensitive liquid egg type, egg white, can be pressure treated to reduce microbe count at a level less than that which causes denaturation. Microbe reduction was smaller in yolk and melange, so higher pressure values are appropriate for these products.

Human autonomic rhythms: vagal cardiac mechanisms in tetraplegic subjects

NASA Technical Reports Server (NTRS)

Koh, J.; Brown, T. E.; Beightol, L. A.; Ha, C. Y.; Eckberg, D. L.

1994-01-01

1. We studied eight young men (age range: 20-37 years) with chronic, clinically complete high cervical spinal cord injuries and ten age-matched healthy men to determine how interruption of connections between the central nervous system and spinal sympathetic motoneurones affects autonomic cardiovascular control. 2. Baseline diastolic pressures and R-R intervals (heart periods) were similar in the two groups. Slopes of R-R interval responses to brief neck pressure changes were significantly lower in tetraplegic than in healthy subjects, but slopes of R-R interval responses to steady-state arterial pressure reductions and increases were comparable. Plasma noradrenaline levels did not change significantly during steady-state arterial pressure reductions in tetraplegic patients, but rose sharply in healthy subjects. The range of arterial pressure and R-R interval responses to vasoactive drugs (nitroprusside and phenylephrine) was significantly greater in tetraplegic than healthy subjects. 3. Resting R-R interval spectral power at respiratory and low frequencies was similar in the two groups. During infusions of vasoactive drugs, low-frequency R-R interval spectral power was directly proportional to arterial pressure in tetraplegic patients, but was unrelated to arterial pressure in healthy subjects. Vagolytic doses of atropine nearly abolished both low- and respiratory-frequency R-R interval spectral power in both groups. 4. Our conclusions are as follows. First, since tetraplegic patients have significant levels of low-frequency arterial pressure and R-R interval spectral power, human Mayer arterial pressure waves may result from mechanisms that do not involve stimulation of spinal sympathetic motoneurones by brainstem neurones. Second, since in tetraplegic patients, low-frequency R-R interval spectral power is proportional to arterial pressure, it is likely to be mediated by a baroreflex mechanism. Third, since low-frequency R-R interval rhythms were nearly abolished by atropine in both tetraplegic and healthy subjects, these rhythms reflect in an important way rhythmic firing of vagal cardiac motoneurones.

Alterations in blood pressure, antioxidant status and caspase 8 expression in cobalt chloride-induced cardio-renal dysfunction are reversed by Ocimum gratissimum and gallic acid in Wistar rats.

PubMed

Akinrinde, A S; Oyagbemi, A A; Omobowale, T O; Asenuga, E R; Ajibade, T O

2016-07-01

The protective abilities of the chloroform extract of Ocimum gratissimum (COG) and gallic acid against cobalt chloride (CoCl2) - induced cardiac and renal toxicity were evaluated. Rats were exposed to CoCl2 (350ppm) for 7 days, either alone, or in combination with COG (100 and 200mg/kg) or gallic acid (120mg/kg). CoCl2 given alone, caused significant increases (p<0.05) in oxidative stress parameters (hydrogen peroxide, H2O2 and malondialdehyde, MDA) and increased expression of the apoptotic initiator caspase 8 in the heart and kidneys. There was significant reduction (p<0.05) in reduced glutathione (GSH) in cardiac and renal tissues; reduction in superoxide dismutase (SOD) activity in the kidneys and adaptive increases in Glutathione S-transferase (GST) and catalase (CAT). CoCl2 also produced significant reduction (p<0.05) in systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressures. Oral COG and gallic acid treatment significantly reduced (p<0.05) the levels of H2O2 and MDA; with reduced expression of caspase 8 and restoration of GSH levels, GPx, SOD and CAT activities, howbeit, to varying degrees in the heart and kidneys. COG (200mg/kg) was most effective in restoring the blood pressures in the rats to near control levels. CoCl2-induced histopathological lesions including myocardial infarction and inflammation and renal tubular necrosis and inflammation were effectively ameliorated by the treatments administered. This study provides evidence for the protective roles of O. gratissimum and gallic acid by modulation of CoCl2-induced alterations in blood pressure, antioxidant status and pro-apoptotic caspase 8 in Wistar rats. Copyright © 2016 Elsevier GmbH. All rights reserved.

Brachial blood flow under relative levels of blood flow restriction is decreased in a nonlinear fashion.

PubMed

Mouser, J Grant; Ade, Carl J; Black, Christopher D; Bemben, Debra A; Bemben, Michael G

2018-05-01

Blood flow restriction (BFR), the application of external pressure to occlude venous return and restrict arterial inflow, has been shown to increase muscular size and strength when combined with low-load resistance exercise. BFR in the research setting uses a wide range of pressures, applying a pressure based upon an individual's systolic pressure or a percentage of occlusion pressure; not a directly determined reduction in blood flow. The relationship between relative pressure and blood flow has not been established. To measure blood flow in the arm under relative levels of BFR. Forty-five people (18-40 years old) participated. Arterial occlusion pressure in the right arm was measured using a 5-cm pneumatic cuff. Blood flow in the brachial artery was measured at rest and at pressures between 10% and 90% of occlusion using ultrasound. Blood flow decreased in a nonlinear, stepped fashion. Blood flow decreased at 10% of occlusion and remained constant until decreasing again at 40%, where it remained until 90% of occlusion. The decrease in brachial blood flow is not proportional to the applied relative pressure. The prescription of blood flow restriction should take into account the stimulus provided at each relative level of blood flow. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

High-sodium intake prevents pregnancy-induced decrease of blood pressure in the rat.

PubMed

Beauséjour, Annie; Auger, Karine; St-Louis, Jean; Brochu, Michéle

2003-07-01

Despite an increase of circulatory volume and of renin-angiotensin-aldosterone system (RAAS) activity, pregnancy is paradoxically accompanied by a decrease in blood pressure. We have reported that the decrease in blood pressure was maintained in pregnant rats despite overactivation of RAAS following reduction in sodium intake. The purpose of this study was to evaluate the impact of the opposite condition, e.g., decreased activation of RAAS during pregnancy in the rat. To do so, 0.9% or 1.8% NaCl in drinking water was given to nonpregnant and pregnant Sprague-Dawley rats for 7 days (last week of gestation). Increased sodium intakes (between 10- and 20-fold) produced reduction of plasma renin activity and aldosterone in both nonpregnant and pregnant rats. Systolic blood pressure was not affected in nonpregnant rats. However, in pregnant rats, 0.9% sodium supplement prevented the decreased blood pressure. Moreover, an increase of systolic blood pressure was obtained in pregnant rats receiving 1.8% NaCl. The 0.9% sodium supplement did not affect plasma and fetal parameters. However, 1.8% NaCl supplement has larger effects during gestation as shown by increased plasma sodium concentration, hematocrit level, negative water balance, proteinuria, and intrauterine growth restriction. With both sodium supplements, decreased AT1 mRNA levels in the kidney and in the placenta were observed. Our results showed that a high-sodium intake prevents the pregnancy-induced decrease of blood pressure in rats. Nonpregnant rats were able to maintain homeostasis but not the pregnant ones in response to sodium load. Furthermore, pregnant rats on a high-sodium intake (1.8% NaCl) showed some physiological responses that resemble manifestations observed in preeclampsia.

Therapeutic effect of captopril, pentoxifylline, and cordyceps sinensis in pre-hepatic portal hypertensive rats.

PubMed

Ahmed, Ahmed F; El-Maraghy, Nabila N; Abdel Ghaney, Rasha H; Elshazly, Shimaa M

2012-01-01

Portal hypertension is an important and potentially fatal complication of liver disease whereby cellular and fibrotic alterations manifest to increase portal venous pressure. The aim of this study is to investigate the effect of captopril, pentoxifylline (PTX), and cordyceps sinensis in pre-hepatic portal hypertensive rats. Wistar male rats were divided at random into 3 main groups: the first group: control rats. The second group: sham-operated rats and the third group: prehepatic portal hypertensive rats (PHPHT) induced by regulated pre-hepatic portal vein ligation. After 14 days, Group 3 was subdivided into 5 subgroups. Subgroup (1): portal vein-ligated (PVL) was killed at once; Subgroup (2): received distilled water for 30 days (untreated PVL group); subgroups 3-5 were treated with captopril (60 mg/kg, orally); PTX (100 mg/kg, orally); and C. sinensis (200 mg/kg, orally), respectively, as a single daily dose for 30 days. Portal pressure, nitric oxide (NO), antioxidant enzymes, Liver enzymes, and creatinine levels were measured to evaluate the status of the liver state. Portal vein ligation produced significant increments in liver enzymes, NO, creatinine and portal pressure concomitant with significant decrements in glutathione content and superoxide dismutase activity. Treatment with captopril, PTX, and C. sinensis resulted in a significant reduction in liver enzymes, NO, creatinine and portal pressure and observable increase in antioxidant enzymes. captopril, PTX, and C. sinensis have promising effect in controlling PHPHT and reducing hyperdynamic circulatory state through reduction of portal pressure and NO level.

Non-linear pressure/temperature-dependence of high pressure thermal inactivation of proteolytic Clostridium botulinum type B in foods.

PubMed

Maier, Maximilian B; Lenz, Christian A; Vogel, Rudi F

2017-01-01

The effect of high pressure thermal (HPT) processing on the inactivation of spores of proteolytic type B Clostridium botulinum TMW 2.357 in four differently composed low-acid foods (green peas with ham, steamed sole, vegetable soup, braised veal) was studied in an industrially feasible pressure range and temperatures between 100 and 120°C. Inactivation curves exhibited rapid inactivation during compression and decompression followed by strong tailing effects. The highest inactivation (approx. 6-log cycle reduction) was obtained in braised veal at 600 MPa and 110°C after 300 s pressure-holding time. In general, inactivation curves exhibited similar negative exponential shapes, but maximum achievable inactivation levels were lower in foods with higher fat contents. At high treatment temperatures, spore inactivation was more effective at lower pressure levels (300 vs. 600 MPa), which indicates a non-linear pressure/temperature-dependence of the HPT spore inactivation efficiency. A comparison of spore inactivation levels achievable using HPT treatments versus a conventional heat sterilization treatment (121.1°C, 3 min) illustrates the potential of combining high pressures and temperatures to replace conventional retorting with the possibility to reduce the process temperature or shorten the processing time. Finally, experiments using varying spore inoculation levels suggested the presence of a resistant fraction comprising approximately 0.01% of a spore population as reason for the pronounced tailing effects in survivor curves. The loss of the high resistance properties upon cultivation indicates that those differences develop during sporulation and are not linked to permanent modifications at the genetic level.

Noise Reduction of Ocean-Bottom Pressure Data Toward Real-Time Tsunami Forecasting

NASA Astrophysics Data System (ADS)

Tsushima, H.; Hino, R.

2008-12-01

We discuss a method of noise reduction of ocean-bottom pressure data to be fed into the near-field tsunami forecasting scheme proposed by Tsushima et al. [2008a]. In their scheme, the pressure data is processed in real time as follows: (1) removing ocean tide components by subtracting the sea-level variation computed from a theoretical tide model, (2) applying low-pass digital filter to remove high-frequency fluctuation due to seismic waves, and (3) removing DC-offset and linear-trend component to determine a baseline of relative sea level. However, it turns out this simple method is not always successful in extracting tsunami waveforms from the data, when the observed amplitude is ~1cm. For disaster mitigation, accurate forecasting of small tsunamis is important as well as large tsunamis. Since small tsunami events occur frequently, successful tsunami forecasting of those events are critical to obtain public reliance upon tsunami warnings. As a test case, we applied the data-processing described above to the bottom pressure records containing tsunami with amplitude less than 1 cm which was generated by the 2003 Off-Fukushima earthquake occurring in the Japan Trench subduction zone. The observed pressure variation due to the ocean tide is well explained by the calculated tide signals from NAO99Jb model [Matsumoto et al., 2000]. However, the tide components estimated by BAYTAP-G [Tamura et al., 1991] from the pressure data is more appropriate for predicting and removing the ocean tide signals. In the pressure data after removing the tide variations, there remain pressure fluctuations with frequencies ranging from about 0.1 to 1 mHz and with amplitudes around ~10 cm. These fluctuations distort the estimation of zero-level and linear trend to define relative sea-level variation, which is treated as tsunami waveform in the subsequent analysis. Since the linear trend is estimated from the data prior to the origin time of the earthquake, an artificial linear trend is produced in the processed waveform. This artificial linear trend degrades the accuracy of the tsunami forecasting, although the forecasting result is expected to be robust against the existence of short-period noise [Tsushima et al., 2008a]. Since the bottom pressure show gradual increase (or decrease) in the tsunami source region [Tsushima et al., 2008b], it is important to remove the linear trend not related to the tsunami generation from the data before fed into the analysis. Therefore, the reduction of the noise in sub-mHz band is critical for the forecasting small tsunamis. Applying a kind of frequency filters to eliminate this noise cannot be a solution for this problem because actual tsunami signals may also contain components of this frequency band. We investigate whether any statistical modelings of the noise are effective for reducing the sub-mHz noise.

The application of high-pressure treatment in the reduction of phosphate levels in breakfast sausages.

PubMed

O'Flynn, C C; Cruz-Romero, M C; Troy, D J; Mullen, A M; Kerry, J P

2014-01-01

This study investigated effects of high pressure (HP) treatment of pork meat at 150 or 300 MPa for 5 min before manufacturing sausages on the reduction of phosphate levels and compared to sausages manufactured with untreated pork meat (control sausages). Improvement in perceived saltiness, juiciness and overall flavour was observed in sausages manufactured using HP-treated meat at 150 MPa and 0% phosphate, compared to control sausages. Sausages manufactured using meat HP-treated at 150 MPa and 0.25% phosphate (P<0.05) improved hardness of sausages. HP-treated meat at 300 MPa and 0% phosphate decreased juiciness and adhesiveness, while at 0.25% phosphate, adversely affected emulsion stability and sensory attributes. HP treatment did not affect significantly the lightness of the sausages; however, elimination of phosphate reduced (P<0.05) the yellowness, while HP treatment at 150 MPa with 0.25 or 0.5% phosphate increased (P<0.05) redness. HP reatment at 150 MPa has potential for reducing phosphate levels in sausages without significant changes in their functionality and improved acceptability. © 2013.

The respiratory pressure-abdominal volume curve in a porcine model.

PubMed

Regli, Adrian; De Keulenaer, Bart Leon; Singh, Bhajan; Hockings, Lisen Emma; Noffsinger, Bill; van Heerden, Peter Vernon

2017-12-01

Increasing intra-abdominal volume (IAV) can lead to intra-abdominal hypertension (IAH) or abdominal compartment syndrome. Both are associated with raised morbidity and mortality. IAH can increase airway pressures and impair ventilation. The relationship between increasing IAV and airway pressures is not known. We therefore assessed the effect of increasing IAV on airway and intra-abdominal pressures (IAP). Seven pigs (41.4 +/-8.5 kg) received standardized anesthesia and mechanical ventilation. A latex balloon inserted in the peritoneal cavity was inflated in 1-L increments until IAP exceeded 40 cmH 2 O. Peak airway pressure (pP AW ), respiratory compliance, and IAP (bladder pressure) were measured. Abdominal compliance was calculated. Different equations were tested that best described the measured pressure-volume curves. An exponential equation best described the measured pressure-volume curves. Raising IAV increased pP AW and IAP in an exponential manner. Increases in IAP were associated with parallel increases in pP AW with an approximate 40% transmission of IAP to pP AW . The higher the IAP, the greater IAV effected pP AW and IAP. The exponential nature of the effect of IAV on pP AW and IAP implies that, in the presence of high grades of IAH, small reductions in IAV can lead to significant reductions in airway and abdominal pressures. Conversely, in the presence of normal IAP levels, large increases in IAV may not affect airway and abdominal pressures.

Effects of Sodium Reduction and the DASH Diet in Relation to Baseline Blood Pressure.

PubMed

Juraschek, Stephen P; Miller, Edgar R; Weaver, Connie M; Appel, Lawrence J

2017-12-12

Both sodium reduction and the DASH (Dietary Approaches to Stop Hypertension) diet, a diet rich in fruits, vegetables, and low-fat dairy products, and reduced in saturated fat and cholesterol, lower blood pressure. The separate and combined effects of these dietary interventions by baseline blood pressure (BP) has not been reported. The authors compared the effects of low versus high sodium, DASH versus control, and both (low sodium-DASH vs. high sodium-control diets) on systolic blood pressure (SBP) by baseline BP. In the DASH-Sodium (Dietary Patterns, Sodium Intake and Blood Pressure) trial, adults with pre- or stage 1 hypertension and not using antihypertensive medications, were randomized to either DASH or a control diet. On either diet, participants were fed each of 3 sodium levels (50, 100, and 150 mmol/day at 2,100 kcal) in random order over 4 weeks separated by 5-day breaks. Strata of baseline SBP were <130, 130 to 139, 140 to 149, and ≥150 mm Hg. Of 412 participants, 57% were women, and 57% were black; mean age was 48 years, and mean SBP/diastolic BP was 135/86 mm Hg. In the context of the control diet, reducing sodium (from high to low) was associated with mean SBP differences of -3.20, -8.56, -8.99, and -7.04 mm Hg across the respective baseline SBP strata listed (p for trend = 0.004). In the context of high sodium, consuming the DASH compared with the control diet was associated with mean SBP differences of -4.5, -4.3, -4.7, and -10.6 mm Hg, respectively (p for trend = 0.66). The combined effects of the low sodium-DASH diet versus the high sodium-control diet on SBP were -5.3, -7.5, -9.7, and -20.8 mm Hg, respectively (p for trend <0.001). The combination of reduced sodium intake and the DASH diet lowered SBP throughout the range of pre- and stage 1 hypertension, with progressively greater reductions at higher levels of baseline SBP. SBP reductions in adults with the highest levels of SBP (≥150 mm Hg) were striking and reinforce the importance of both sodium reduction and the DASH diet in this high-risk group. Further research is needed to determine the effects of these interventions among adults with SBP ≥160 mm Hg. (Dietary Patterns, Sodium Intake and Blood Pressure [DASH-Sodium]; NCT00000608). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Post-suspension hypotension is attenuated in Sprague-Dawley rats by prostacyclin synthase inhibition

NASA Technical Reports Server (NTRS)

Bayorh, M. A.; Eatman, D.; Walton, M.; Socci, R. R.; Emmett, N.

2002-01-01

Cardiovascular deconditioning, sometimes manifested in astronauts during standing postflight, may be related to the impairment of autonomic function and/or excessive production of endothelium-dependent relaxing factors. In the present study, we examined the cardiovascular responses to 7-day 30 degrees tail-suspension and a subsequent 6-h post-suspension period in conscious male Sprague-Dawley rats to determine the role of prostacyclin in the observed post-suspension reduction in mean arterial pressure (MAP). The specific prostacyclin synthase inhibitor U-51605 (0.3 mg/kg), or saline, was administered intravenously prior to release from suspension and at 2 and 4 h post-suspension. During 7 days of suspension, MAP did not change, however, there was a post-suspension reduction in MAP which was associated with significant increases in plasma prostacyclin and nitric oxide. U-51605 attenuated the observed post-suspension hypotension and reduced plasma prostacyclin levels, but not nitric oxide levels. The baroreflex sensitivity for heart rate was modified by U-51605: increased MAP threshold and effective MAP range. Thus, the post-suspension reduction in mean arterial pressure may be due to overproduction of prostacyclin and/or other endothelium-dependent relaxing factors and alteration in baroreflex activity.

Health Gain by Salt Reduction in Europe: A Modelling Study

PubMed Central

Hendriksen, Marieke A. H.; van Raaij, Joop M. A.; Geleijnse, Johanna M.; Breda, Joao; Boshuizen, Hendriek C.

2015-01-01

Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France, Ireland, Italy, Netherlands, Poland, Spain, Sweden and United Kingdom). Through literature research we obtained current salt intake and systolic blood pressure levels of the nine countries. The population health modeling tool DYNAMO-HIA including country-specific disease data was used to predict the changes in prevalence of ischemic heart disease and stroke for each country estimating the effect of salt reduction through its effect on blood pressure levels. A 30% salt reduction would reduce the prevalence of stroke by 6.4% in Finland to 13.5% in Poland. Ischemic heart disease would be decreased by 4.1% in Finland to 8.9% in Poland. When salt intake is reduced to the WHO population nutrient goal, it would reduce the prevalence of stroke from 10.1% in Finland to 23.1% in Poland. Ischemic heart disease would decrease by 6.6% in Finland to 15.5% in Poland. The number of postponed deaths would be 102,100 (0.9%) in France, and 191,300 (2.3%) in Poland. A reduction of salt intake to 5 grams per day is expected to substantially reduce the burden of cardiovascular disease and mortality in several European countries. PMID:25826317

Responses of aortic depressor nerve-evoked neurones in rat nucleus of the solitary tract to changes in blood pressure

PubMed Central

Zhang, Jing; Mifflin, Steven W

2000-01-01

Using electrophysiological techniques, the discharge of neurones in the nucleus of the solitary tract (NTS) receiving aortic depressor nerve (ADN) inputs was examined during blood pressure changes induced by I.V. phenylephrine or nitroprusside in anaesthetized, paralysed and artificially ventilated rats. Various changes in discharge rate were observed during phenylephrine-induced blood pressure elevations: an increase (n = 38), a decrease (n = 5), an increase followed by a decrease (n = 4) and no response (n = 11). In cells receiving a monosynaptic ADN input (MSNs), the peak discharge frequency response was correlated to the rate of increase in mean arterial pressure (P < 0.01) but was not correlated to the absolute increase in blood pressure. The peak discharge frequency response of cells receiving a polysynaptic ADN input (PSNs) was correlated to neither the absolute increase in blood pressure nor the rate of increase in mean arterial pressure. Diverse changes in discharge rate were observed during nitroprusside-induced reductions in blood pressure: an increase (n = 3), a decrease (n = 10), an increase followed by a decrease (n = 3) and no response (n = 6). Reductions in pressure of 64 ± 2 mmHg produced weak reductions in spontaneous discharge of 1.3 ± 0.9 Hz and only totally abolished spontaneous discharge in one neurone. These response patterns of NTS neurones during changes in arterial pressure suggest that baroreceptor inputs are integrated differently in MSNs compared to PSNs. The sensitivity of MSNs to the rate of change of pressure provides a mechanism for the rapid regulation of cardiovascular function. The lack of sensitivity to the mean level of a pressure increase in both MSNs and PSNs suggests that steady-state changes in pressure are encoded by the number of active neurones and not graded changes in the discharge of individual neurones. Both MSNs and PSNs receive tonic excitatory inputs from the arterial baroreceptors; however, these tonic inputs appear to be insufficient to totally account for their spontaneous discharge. PMID:11101652

Dietary sodium intake: scientific basis for public policy.

PubMed

Whelton, Paul K

2015-01-01

National and international agencies recommend a reduction in dietary sodium intake. However, some have questioned the wisdom of these policies. The goal of this report was to assess the findings and quality of studies that have examined the relationship between dietary sodium and both blood pressure and cardiovascular disease. Literature review of the available observational studies and randomized controlled trials, including systematic reviews and meta-analyses. A large body of evidence from observational studies and clinical trials documents a direct relationship between dietary sodium intake and the level of blood pressure, especially in persons with a higher level of blood pressure, African-Americans, and those who are older or have comorbidity, including chronic kidney disease. A majority of the available observational reports support the presence of a direct relationship between dietary sodium intake and cardiovascular disease but the quality of the evidence according to most studies is poor. The limited information available from clinical trials is consistent with a beneficial effect of reduced sodium intake on incidence of cardiovascular disease. The scientific underpinning for policies to reduce the usual intake of dietary sodium is strong. In the United States and many other countries, addition of sodium during food processing has led to a very high average intake of dietary sodium, with almost everyone exceeding the recommended goals. National programs utilizing voluntary and mandatory approaches have resulted in a successful reduction in sodium intake. Even a small reduction in sodium consumption is likely to yield sizable improvement in population health. © 2015 S. Karger AG, Basel.

Short-duration spaceflight impairs human carotid baroreceptor-cardiac reflex responses

NASA Astrophysics Data System (ADS)

Fritsch, Janice M.; Charles, John B.; Bennett, Barbara S.; Jones, Michele M.; Eckberg, Dwain L.

1992-08-01

The effect of a spaceflight on the vagally mediated baroreceptor-cardiac reflex responses of humans were investigated by measuring the responses (provoked by neck pressure changes) in supine position and the heart rate and blood pressure in the supine and standing positions in 16 astronauts before and after 4- to 5-day long Space Shuttle missions. The results showed that exposures to spaceflight resulted in reduced baseline levels of the vagal-cardiac outflow and the vagally mediated responses to changes of the arterial baroreceptor input and that these changes contribute to postflight reductions of astronauts' ability to maintain standing arterial pressures.

Effect of varying the pressurisation rate during noninvasive pressure support ventilation.

PubMed

Prinianakis, G; Delmastro, M; Carlucci, A; Ceriana, P; Nava, S

2004-02-01

The aim of the study was to assess the effects of varying the pressurisation rate during noninvasive pressure support ventilation on patients' breathing pattern, inspiratory effort, arterial blood gases, tolerance to ventilation and amount of air leakage. A total of 15 chronic obstructive pulmonary disease patients recovering from an acute episode of hypercapnic acute respiratory failure were studied during four randomised trials with different levels of pressurisation rate. No significant changes were observed in breathing pattern and arterial blood gases between the different runs. The pressure time product of the diaphragm, an estimate of its metabolic consumption, was significantly lower with all pressurisation rates than with spontaneous breathing, but was significantly lowest with the fastest rate. However, air leak, assessed by the ratio between expired and inspired tidal volumes, increased and the patients' tolerance of ventilation, measured using a standardised scale, was significantly poorer with the fastest pressurisation rate. In chronic obstructive pulmonary disease patients recovering from an episode of acute hypercapnic respiratory failure and ventilated with noninvasive pressure support ventilation, different pressurisation rates resulted in different reductions in the pressure time product of the diaphragm; this reduction was greater with the fastest rate, but was accompanied by significant air leaks and poor tolerance.

Is topical haloperidol a useful glaucoma treatment?

PubMed Central

Lavin, M. J.; Andrews, V.

1986-01-01

A randomised, double blind, single dose study of topical haloperidol, a dopamine receptor blocking drug, was performed on 20 healthy volunteers. After its administration a modest reduction in intraocular pressure was recorded over the six-hour study period, but the difference was not significant at the p less than 0.05 level. Although dopamine blocking agents are effective in reducing intraocular pressure in experimental animals, topical haloperidol appears unlikely to be clinically useful in the treatment of glaucoma. PMID:3718908

Blood pressure reduction due to hemoglobin glycosylation in type 2 diabetic patients

PubMed Central

Cabrales, Pedro; Vázquez, Miguel A Salazar; Vázquez, Beatriz Y Salazar; Rodríguez-Morán, Martha; Intaglietta, Marcos; Guerrero-Romero, Fernando

2008-01-01

Objective: To test the hypothesis that glycosylation of hemoglobin constitutes a risk factor for hypertension. Methods: A total of 129 relative uniform diabetic subjects (86 women and 42 men) were enrolled in a cross sectional study. Exclusion criteria included alcohol consumption, smoking, ischemic heart disease, stroke, neoplasia, renal, hepatic, and chronic inflammatory disease. Systolic and diastolic pressures were recorded in subsequent days and mean arterial blood pressure (MAP) was determined. Hemoglobin glycosylation was measured by determining the percentage glycosylated hemoglobin (HbA1c) by means of the automated microparticle enzyme immunoassay test. Results: MAP was found to be independent of the concentration of HbA1c; however, correcting MAP for the variability in hematocrit, to evidence the level of vasoconstriction (or vasodilatation) showed that MAP is negatively correlated with the concentration of HbA1c (p for trend <0.05), when patients treated for hypertension are excluded from the analysis. Patients treated for hypertension showed the opposite trend with increasing MAP as HbA1c increased (p for the difference in trends <0.05). Conclusions: Glycosylation per se appears to lead to blood pressure reduction in type 2 diabetic patients untreated for hypertension. Treatment for hypertension may be associated with a level of endothelial dysfunction that interferes with the antihypertensive effect of HbA1c. PMID:19066010

A theoretical investigation of noise reduction through the cylindrical fuselage of a twin-engine, propeller-driven aircraft

NASA Technical Reports Server (NTRS)

Bhat, R. B.; Mixson, J. S.

1978-01-01

Interior noise in the fuselage of a twin-engine, propeller-driven aircraft with two propellers rotating in opposite directions is studied analytically. The fuselage was modeled as a stiffened cylindrical shell with simply supported ends, and the effects of stringers and frames were averaged over the shell surface. An approximate mathematical model of the propeller noise excitation was formulated which includes some of the propeller noise characteristics such as sweeping pressure waves around the sidewalls due to propeller rotation and the localized nature of the excitation with the highest levels near the propeller plane. Results are presented in the form of noise reduction, which is the difference between the levels of external and interior noise. The influence of propeller noise characteristics on the noise reduction was studied. The results indicate that the sweep velocity of the excitation around the fuselage sidewalls is critical to noise reduction.

Effect of pressure and magnetic field on the electrical resistivity of TbB6

NASA Astrophysics Data System (ADS)

Sakai, Takeshi; Oomi, Gendo; Kunii, Satoru

2009-06-01

Electrical resistivity of a single crystal of TbB6 was studied under hydrostatic pressures up to 2.1 GPa and magnetic fields up to 9 T. The Néel temperature, rN, decreases linearly with increasing pressure: \\ddiff lnTN/\\ddiff P = 3.14×10-2 GPa-1 at zero external field. This pressure dependence of TN weakens as external fields increase. At ambient pressure, the magnetoresistance at 4.2 K is positive up to 4.8 T and becomes negative above 4.8 T. The positive magnetoresistance observed at ambient pressure is suppressed by applying pressure, which enhances the negative magnetoresistance. These results are interpreted in terms of the reduction of the scattering of conduction electrons, due to disordered magnetic moment being suppressed by derealization of 4f electrons at high pressure, and the magnetic field variation of the large transition probability between the ground state and the excited levels.

Effect of high pressure on the electrical resistivity of Ge-Te-In glasses

NASA Astrophysics Data System (ADS)

Prasad, K. N. N.; Varma, G. Sreevidya; Rukmani, K.; Asokan, S.

2015-06-01

The variation in the electrical resistivity of the chalcogenide glasses Ge15Te85-xInx has been studied as a function of high pressure for pressures up to 8.5GPa. All the samples studied undergo a semi-conductor to metallic transition in a continuous manner at pressures between 1.5-2.5GPa. The transition pressure at which the samples turn metallic increases with increase in percentage of Indium. This increase is a direct consequence of the increase in network rigidity with the addition of Indium. At a constant pressure of 0.5GPa, the normalized resistivity shows some signature of the existence of the intermediate phase. Samples recovered after a pressure cycle remain amorphous suggesting that the semi-conductor to metallic transition arises from a reduction of the band gap due to pressure or the movement of the Fermi level into the conduction or valence band.

Neuropeptide Y as an indicator of successful alterations in sympathetic nervous activity after renal sympathetic denervation.

PubMed

Dörr, Oliver; Ewen, Sebastian; Liebetrau, Christoph; Möllmann, Helge; Gaede, Luise; Linz, Dominik; Hohl, Mathias; Troidl, Christian; Bauer, Timm; Böhm, Michael; Hamm, Christian; Mahfoud, Felix; Nef, Holger

2015-12-01

Renal sympathetic denervation (RSD) represents a safe and effective treatment option for certain patients with resistant hypertension and has been shown to decrease sympathetic activity. Neuropeptide Y (NPY) is a neurotransmitter that is co-released with norepinephrine and is up-regulated during increased sympathetic activity. The aim of the present study was to examine the effect of RSD on NPY and to analyze the association between changes in NPY levels and blood pressure reduction after RSD. A total of 150 consecutive patients (age 64.9 ± 10.2 years) from three clinical centers undergoing RSD were included in this study. Response to RSD was defined as an office systolic blood pressure (SBP) reduction of >10 mmHg 6 months after RSD. Venous blood samples for measurement of NPY were collected prior to and 6 months after RSD. BP and NPY levels were significantly reduced by 23/9 mmHg (p = 0.001/0.001) and 0.24 mg/dL (p < 0.01) 6 months after RSD. There was a significant correlation between baseline SBP- and RSD-related systolic BP reduction (r = -0.43; p < 0.001) and between serum NPY baseline values and NPY level changes (r = -0.52; p < 0.001) at the 6-month follow-up. The BP response to RSD (>10 mmHg) was associated with a significantly greater reduction in NPY level when compared with BP non-responders (p = 0.001). This study demonstrates an effect of RSD on serum NPY levels, a specific marker for sympathetic activity. The association between RSD-related changes in SBP and NPY levels provides further evidence of the effect of RSD on the sympathetic nervous system.

Importance of the mitral apparatus for left ventricular function: an experimental approach.

PubMed

Gams, E; Hagl, S; Schad, H; Heimisch, W; Mendler, N; Sebening, F

1992-01-01

In an experimental study of 31 anesthetized dogs the importance of the mitral apparatus for the left ventricular function was investigated. During extracorporeal circulation bileaflet mitral valve prostheses were implanted preserving the mitral subvalvular apparatus. Flexible wires were slung around the chordae tendineae and exteriorized through the left ventricular wall to cut the chordae by electrocautery from the outside when the heart was beating again. External and internal left ventricular dimensions were measured by sonomicrometry, left ventricular stroke volume by electromagnetic flowmeters around the ascending aorta, left ventricular end-diastolic volume by dye dilution technique, and left ventricular pressure by catheter tip manometers. Different preload levels were achieved by volume loading with blood transfusion before and after cutting the chordae tendineae. When the chordae had been divided peak systolic left ventricular pressure did not change. Heart rate only increased at the lowest left ventricular end-diastolic pressures of 3-4 mmHg, but remained unchanged at higher preload levels. Cardiac output decreased significantly up to -9% at left ventricular end-diastolic pressures of 5-10 mmHg, while left ventricular dp/dtmax showed a consistent reduction of up to -15% at any preload level. Significant reductions were also seen in systolic shortening in the left ventricular major axis (by external measurements -27%, by internal recording -43%). Left ventricular end-diastolic dimensions increased in the major axis by +2% when recorded externally, by +10% when measured internally. Systolic and diastolic changes in the minor axis were not consistent and different in the external and internal recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of high pressure treatment on liquid whole egg

NASA Astrophysics Data System (ADS)

Németh, Csaba; Dalmadi, István; Mráz, Balázs; Friedrich, László; Zeke, Ildikó; Juhász, Réka; Suhajda, Ágnes; Balla, Csaba

2012-06-01

In our tests, we artificially infected liquid whole egg samples with Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus bacteria, and then treated the samples in "Food Lab900" high hydrostatic pressure (HHP) instrument for 3-17 min at 200-400 MPa. Subsequently, the change of the viable cell count of the specific bacteria has been tested. In addition to the samples infected with various bacteria, non-infected samples were also treated in each test and the change in viable cell count, colour and viscosity of the samples upon the effect of the treatment. In summary, it can be concluded that in each test of our investigations, the viable cell count of S. enteritidis critical for egg products is reduced significantly, while the reduction of the total viable cell count was around two magnitudes. Additionally, based on our results, microbial destruction, reduction of enthalpy (denaturation of egg white) caused by the treatment at HPP, and colour change are primarily affected by the pressure level, while the changes in rheological properties are also significantly affected by the duration of high pressure treatment (p<0.05).

Assessment of Closed-Loop Control Using Multi-Mode Sensor Fusion For a High Reynolds Number Transonic Jet

NASA Astrophysics Data System (ADS)

Low, Kerwin; Elhadidi, Basman; Glauser, Mark

2009-11-01

Understanding the different noise production mechanisms caused by the free shear flows in a turbulent jet flow provides insight to improve ``intelligent'' feedback mechanisms to control the noise. Towards this effort, a control scheme is based on feedback of azimuthal pressure measurements in the near field of the jet at two streamwise locations. Previous studies suggested that noise reduction can be achieved by azimuthal actuators perturbing the shear layer at the jet lip. The closed-loop actuation will be based on a low-dimensional Fourier representation of the hydrodynamic pressure measurements. Preliminary results show that control authority and reduction in the overall sound pressure level was possible. These results provide motivation to move forward with the overall vision of developing innovative multi-mode sensing methods to improve state estimation and derive dynamical systems. It is envisioned that estimating velocity-field and dynamic pressure information from various locations both local and in the far-field regions, sensor fusion techniques can be utilized to ascertain greater overall control authority.

Effects of Sacubitril/Valsartan (LCZ696) on Natriuresis, Diuresis, Blood Pressures, and NT-proBNP in Salt-Sensitive Hypertension.

PubMed

Wang, Tzung-Dau; Tan, Ru-San; Lee, Hae-Young; Ihm, Sang-Hyun; Rhee, Moo-Yong; Tomlinson, Brian; Pal, Parasar; Yang, Fan; Hirschhorn, Elizabeth; Prescott, Margaret F; Hinder, Markus; Langenickel, Thomas H

2017-01-01

Salt-sensitive hypertension (SSH) is characterized by impaired sodium excretion and subnormal vasodilatory response to salt loading. Sacubitril/valsartan (LCZ696) was hypothesized to increase natriuresis and diuresis and result in superior blood pressure control compared with valsartan in Asian patients with SSH. In this randomized, double-blind, crossover study, 72 patients with SSH received sacubitril/valsartan 400 mg and valsartan 320 mg once daily for 4 weeks each. SSH was diagnosed if the mean arterial pressure increased by ≥10% when patients switched from low (50 mmol/d) to high (320 mmol/d) sodium diet. The primary outcome was cumulative 6- and 24-hour sodium excretion after first dose administration. Compared with valsartan, sacubitril/valsartan was associated with a significant increase in natriuresis (adjusted treatment difference: 24.5 mmol/6 hours, 50.3 mmol/24 hours, both P<0.001) and diuresis (adjusted treatment difference: 291.2 mL/6 hours, P<0.001; 356.4 mL/24 hours, P=0.002) on day 1, but not on day 28, and greater reductions in office and ambulatory blood pressure on day 28. Despite morning dosing of both drugs, ambulatory blood pressure reductions were more pronounced at nighttime than at daytime or the 24-hour average. Compared with valsartan, sacubitril/valsartan significantly reduced N-terminal pro B-type natriuretic peptide levels on day 28 (adjusted treatment difference: -20%; P=0.001). Sacubitril/valsartan and valsartan were safe and well tolerated with no significant changes in body weight or serum sodium and potassium levels with either treatments. In conclusion, sacubitril/valsartan compared with valsartan was associated with short-term increases in natriuresis and diuresis, superior office and ambulatory blood pressure control, and significantly reduced N-terminal pro B-type natriuretic peptide levels in Asian patients with SSH. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01681576. © 2016 American Heart Association, Inc.

Potential application of high hydrostatic pressure to eliminate Escherichia coli O157:H7 on alfalfa sprouted seeds.

PubMed

Neetoo, Hudaa; Ye, Mu; Chen, Haiqiang

2008-12-10

Sprouts eaten raw are increasingly being perceived as hazardous foods as they have been implicated in Escherichia coli O157:H7 outbreaks where the seeds were found to be the likely source of contamination. The objective of our study was to evaluate the potential of using high hydrostatic pressure (HHP) technology for alfalfa seed decontamination. Alfalfa seeds inoculated with a cocktail of five strains of E. coli O157:H7 were subjected to pressures of 500 and 600 MPa for 2 min at 20 degrees C in a dry or wet (immersed in water) state. Immersing seeds in water during pressurization considerably enhanced inactivation of E. coli O157:H7 achieving reductions of 3.5 log and 5.7 log at 500 and 600 MPa, respectively. When dry seeds were pressurized, both pressure levels reduced the counts by <0.7 log. To test the efficacy of HHP to completely decontaminate seeds whilst meeting the FDA requirement of 5 log reductions, seeds inoculated with a ~5 log CFU/g of E. coli O157:H7 were pressure-treated at 600 and 650 MPa at 20 degrees C for holding times of 2 to 20 min. A >5 log reduction in the population was achieved when 600 MPa was applied for durations of > or =6 min although survivors were still detected by enrichment. When the pressure was stepped up to 650 MPa, the threshold time required to achieve complete elimination was 15 min. Un-inoculated seeds pressure-treated at 650 MPa for 15 min at 20 degrees C successfully sprouted achieving a germination rate identical to untreated seeds after eight days of sprouting. These results therefore demonstrate the promising application of HHP on alfalfa seeds to eliminate the risk of E. coli O157:H7 infections associated with consumption of raw alfalfa sprouts.

Bench experiments comparing simulated inspiratory effort when breathing helium-oxygen mixtures to that during positive pressure support with air.

PubMed

Martin, Andrew R; Katz, Ira M; Jenöfi, Katharina; Caillibotte, Georges; Brochard, Laurent; Texereau, Joëlle

2012-10-03

Inhalation of helium-oxygen (He/O2) mixtures has been explored as a means to lower the work of breathing of patients with obstructive lung disease. Non-invasive ventilation (NIV) with positive pressure support is also used for this purpose. The bench experiments presented herein were conducted in order to compare simulated patient inspiratory effort breathing He/O2 with that breathing medical air, with or without pressure support, across a range of adult, obstructive disease patterns. Patient breathing was simulated using a dual-chamber mechanical test lung, with the breathing compartment connected to an ICU ventilator operated in NIV mode with medical air or He/O2 (78/22 or 65/35%). Parabolic or linear resistances were inserted at the inlet to the breathing chamber. Breathing chamber compliance was also varied. The inspiratory effort was assessed for the different gas mixtures, for three breathing patterns, with zero pressure support (simulating unassisted spontaneous breathing), and with varying levels of pressure support. Inspiratory effort increased with increasing resistance and decreasing compliance. At a fixed resistance and compliance, inspiratory effort increased with increasing minute ventilation, and decreased with increasing pressure support. For parabolic resistors, inspiratory effort was lower for He/O2 mixtures than for air, whereas little difference was measured for nominally linear resistance. Relatively small differences in inspiratory effort were measured between the two He/O2 mixtures. Used in combination, reductions in inspiratory effort provided by He/O2 and pressure support were additive. The reduction in inspiratory effort afforded by breathing He/O2 is strongly dependent on the severity and type of airway obstruction. Varying helium concentration between 78% and 65% has small impact on inspiratory effort, while combining He/O2 with pressure support provides an additive reduction in inspiratory effort. In addition, breathing He/O2 alone may provide an alternative to pressure support in circumstances where NIV is not available or poorly tolerated.

Factors associated with positive outcomes in 131 patients treated with gauze-based negative pressure wound therapy.

PubMed

Dunn, Raymond; Hurd, Theresa; Chadwick, P; Cote, Julien; Cockwill, John; Mole, Trevor; Smith, Jennifer

2011-01-01

Negative Pressure Wound Therapy (NPWT) is commonly used in many surgical specialties to improve wound management and healing outcomes. This study reports the ability of gauze-based NPWT to address several treatment goals commonly defined at the onset of therapy. A prospective, multi-center, non-comparative clinical investigation was carried out using gauze-based NPWT in chronic and acute wounds. 131 patients including traumatic, post-surgical and chronic wounds were assessed. Weekly percentage reductions in wound area, depth and volume were 8.3%, 15.8% and 20.5% respectively (p < 0.001). A reduction in exudate level was observed from baseline to treatment discontinuation (p < 0.001). An increase (p = 0.007) in red granulation tissue and a decrease (p < 0.001) in non-viable tissue was observed. Baseline wound characteristics associated with slower rates of progress included chronic wound aetiologies, longer wound duration prior to NPWT and presence of diabetes as a co-morbidity. Important indicators of wounds which had improved sufficiently and no longer required NPWT included reduction in volume and exudate levels. Gauze-based NPWT can be used to address many of the treatment goals commonly defined at the onset of therapy including reduction in wound volume, management of exudate and infection status, and improvement in wound bed quality. Copyright © 2011 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Active control of fan noise

NASA Astrophysics Data System (ADS)

Yamasaki, Nobuhiko; Tajima, Hirotoshi

2008-06-01

In the wake-rotor interaction fan noise, a number of the interacting modes at the blade passing frequency (BPF) and its harmonics are generated which are prescribed by the number of stator and rotor blades etc. In the present study, the dominant mode is tried to be suppressed by the secondary sound from the loudspeaker actuators. One of the novel features of the present system is the adoption of the control board with the Field Programmable Gate Array (FPGA) hardware and the LabVIEW software to synchronize the circumferentially installed loudspeaker actuators with the relative location of rotational blades under arbitrary fan rotational speeds. The experiments were conducted under the conditions of three rotational speeds of 2004, 3150, and 4002 [rpm]. The reduction in the sound pressure level (SPL) was observed for all three rotational speeds. The sound pressure level at the BPF was reduced approximately 13 [dB] for 2004 [rpm] case, but not so large reduction was attained for other cases probably due to the inefficiency of the loudspeaker actuators at high frequencies

Development of a nuclear technique for monitoring water levels in pressurized vehicles

NASA Technical Reports Server (NTRS)

Singh, J. J.; Davis, W. T.; Mall, G. H.

1983-01-01

A new technique for monitoring water levels in pressurized stainless steel cylinders was developed. It is based on differences in attenuation coefficients of water and air for Cs137 (662 keV) gamma rays. Experimentally observed gamma ray counting rates with and without water in model reservoir cylinder were compared with corresponding calculated values for two different gamma ray detection theshold energies. Calculated values include the effects of multiple scattering and attendant gamma ray energy reductions. The agreement between the measured and calculated values is reasonably good. Computer programs for calculating angular and spectral distributions of scattered radition in various media are included.

Intraocular pressure reduction and regulation system

NASA Technical Reports Server (NTRS)

Baehr, E. F.; Burnett, J. E.; Felder, S. F.; Mcgannon, W. J.

1979-01-01

An intraocular pressure reduction and regulation system is described and data are presented covering performance in: (1) reducing intraocular pressure to a preselected value, (2) maintaining a set minimum intraocular pressure, and (3) reducing the dynamic increases in intraocular pressure resulting from external loads applied to the eye.

The reduction of takeoff ground roll by the application of a nose gear jump strut

NASA Technical Reports Server (NTRS)

Eppel, Joseph C.; Maisel, Martin D.; Mcclain, J. Greer; Luce, W.

1994-01-01

A series of flight tests were conducted to evaluate the reduction of takeoff ground roll distance obtainable from a rapid extension of the nose gear strut. The NASA Quiet Short-haul Research Aircraft (QSRA) used for this investigation is a transport-size short take off and landing (STOL) research vehicle with a slightly swept wing that employs the upper surface blowing (USB) concept to attain the high lift levels required for its low-speed, short-field performance. Minor modifications to the conventional nose gear assembly and the addition of a high-pressure pneumatic system and a control system provided the extendable nose gear, or jump strut, capability. The limited flight test program explored the effects of thrust-to-weight ratio, wing loading, storage tank initial pressure, and control valve open time duration on the ground roll distance. The data show that a reduction of takeoff ground roll on the order of 10 percent was achieved with the use of the jump strut, as predicted. Takeoff performance with the jump strut was also found to be essentially independent of the pneumatic supply pressure and was only slightly affected by control valve open time within the range of the parameters examined.

Investigation of gene expression and serum levels of PIN1 and eNOS with high blood pressure in patients with Alzheimer disease.

PubMed

Azimi, Mina; Nikanfar, Masoud; Khakikhatibi, Fatemeh; Rahbarghazi, Reza; Nourazarian, Seyed Manuchehr; Biray Avci, Cigir; Nourazarian, Alireza

2017-09-01

According to evidence, Alzheimer's disease is known as one of the most serious neurodegenerative diseases, for which hypertension has been observed to be a key risk factor. Therefore, this study aims to examine the relationship between the PIN1 and eNOS genes expression, as well as serum levels and hypertension in Alzheimer's disease sufferers. Blood samples were obtained from subjects who were divided into four groups: the control group, normotensive Alzheimer's patients, the Alzheimer's sufferers group with hypertension, and the healthy group with only hypertension, considering the inhibition of confounding factors. Thereafter, eNOS and PIN1 genes expression along with serum levels were studied. Based on the obtained results, a statistically significant correlation didn't exist between serum level of PIN1 and the systolic and diastolic blood pressure, between serum level of eNOS and diastolic blood pressure in the norm tension Alzheimer's disease patients, between serum levels of PIN1, eNOS and systolic blood pressure, and between serum eNOS and systolic and diastolic blood pressure in the patients with hypertension (p<0.05). According to the results obtained from this study, measuring the serum levels of eNOS and Pin1 may contribute to the prognosis, prevention, and monitoring of hypertension and also to the reduction of death rates from cardiovascular diseases in Alzheimer's disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

Parameter dependence of ELM loss reduction by magnetic perturbations at low pedestal density and collisionality in ASDEX upgrade

NASA Astrophysics Data System (ADS)

Leuthold, N.; Suttrop, W.; Fischer, R.; Kappatou, A.; Kirk, A.; McDermott, R.; Mlynek, A.; Valovič, M.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

2017-05-01

ELM mitigation by magnetic perturbations is studied at low pedestal collisionalities down to ITER-like values ({ν }{e,{PED}}* =0.1) in ASDEX Upgrade. A comprehensive database of ELM energy losses for varying plasma density, heating power, edge safety factor and magnetic perturbation structure has been assembled to investigate parameter dependencies of ELM mitigation. It is found that magnetic perturbations with a toroidal mode number n = 2 can reduce the ELM energy loss normalized to the energy stored in the plasma pedestal from about 30% to less than 5%, i.e. by a factor of six, below an electron pedestal collisionality of {ν }{e,{PED}}* =0.4. At this level of ELM mitigation a significant reduction of the pedestal pressure and, therefore, global plasma confinement occurs. This pedestal pressure reduction is mostly due to a reduction of plasma density, the so-called ‘pump-out’ effect. Refueling by neutral beams and in particular by pellet injection is possible and can re-establish confinement, however, the ELM energy loss increases as well with increasing density.

Assessment of nurses' knowledge on evidence-based preventive practices for pressure ulcer risk reduction in patients with impaired mobility.

PubMed

Akese, M I; Adejumo, P O; Ilesanmi, R E; Obilor, H N

2014-09-01

The increase in the prevalence of pressure ulcer among patients with impaired physical mobility has currently been associated with nurses' inadequate knowledge of preventive interventions. To assess nurses' knowledge of pressure ulcer identification/staging, risk factors and evidence-based preventive practices. This descriptive study was carried out at the University Teaching Hospital Maiduguri (UMTH), Borno State, Nigeria. Total sampling technique was utilized in the recruitment of the study participants. An adapted 75-item-pressure ulcer questionnaire was used for data collection. The data were analyzed using SPSS version 16. The hypotheses on nurses' knowledge were tested at 0.05 level of significance using Chi square test. A total of 219 nurses participated in this study with response rate of 68.0%. The nurses' years of professional practice ranged from 1 to 35 years with a mean of 11.7 (± 7.8) years. Approximately, 73% of the nurses demonstrated a low level of knowledge of pressure ulcer identification/staging, 69.4% demonstrated an average level of knowledge of risk factors and 79.9% demonstrated high level of knowledge of preventive practices. The relationship between nurses' knowledge of risk factors and knowledge of preventive practices (p = 0.37) was not significant. Nurses demonstrated a knowledge deficit in core areas on pressure ulcer identification/staging, risk factors' assessment and evidence-based preventive practices. In order to address this dearth, there is a need to institute an educational-based practice-guideline on pressure ulcer prevention for nurses.

In-Situ Nondestructive Evaluation of Kevlar(Registered Trademark)and Carbon Fiber Reinforced Composite Micromechanics for Improved Composite Overwrapped Pressure Vessel Health Monitoring

NASA Technical Reports Server (NTRS)

Waller, Jess; Saulsberry, Regor

2012-01-01

NASA has been faced with recertification and life extension issues for epoxy-impregnated Kevlar 49 (K/Ep) and carbon (C/Ep) composite overwrapped pressure vessels (COPVs) used in various systems on the Space Shuttle and International Space Station, respectively. Each COPV has varying criticality, damage and repair histories, time at pressure, and pressure cycles. COPVs are of particular concern due to the insidious and catastrophic burst-before-leak failure mode caused by stress rupture (SR) of the composite overwrap. SR life has been defined [1] as the minimum time during which the composite maintains structural integrity considering the combined effects of stress level(s), time at stress level(s), and associated environment. SR has none of the features of predictability associated with metal pressure vessels, such as crack geometry, growth rate and size, or other features that lend themselves to nondestructive evaluation (NDE). In essence, the variability or surprise factor associated with SR cannot be eliminated. C/Ep COPVs are also susceptible to impact damage that can lead to reduced burst pressure even when the amount of damage to the COPV is below the visual detection threshold [2], thus necessitating implementation of a mechanical damage control plan [1]. Last, COPVs can also fail prematurely due to material or design noncompliance. In each case (SR, impact or noncompliance), out-of-family behavior is expected leading to a higher probability of failure at a given stress, hence, greater uncertainty in performance. For these reasons, NASA has been actively engaged in research to develop NDE methods that can be used during post-manufacture qualification, in-service inspection, and in-situ structural health monitoring. Acoustic emission (AE) is one of the more promising NDE techniques for detecting and monitoring, in real-time, the strain energy release and corresponding stress-wave propagation produced by actively growing flaws and defects in composite materials [3,4,5,6,7,8]. To gain further insight into the mechanisms responsible for composite rupture, broadband modal acoustic emission analysis was used. Also, since AE data reduction proved to be very time consuming, specialized data reduction software was written to automate the process.

Evaluation of atomic pressure in the multiple time-step integration algorithm.

PubMed

Andoh, Yoshimichi; Yoshii, Noriyuki; Yamada, Atsushi; Okazaki, Susumu

2017-04-15

In molecular dynamics (MD) calculations, reduction in calculation time per MD loop is essential. A multiple time-step (MTS) integration algorithm, the RESPA (Tuckerman and Berne, J. Chem. Phys. 1992, 97, 1990-2001), enables reductions in calculation time by decreasing the frequency of time-consuming long-range interaction calculations. However, the RESPA MTS algorithm involves uncertainties in evaluating the atomic interaction-based pressure (i.e., atomic pressure) of systems with and without holonomic constraints. It is not clear which intermediate forces and constraint forces in the MTS integration procedure should be used to calculate the atomic pressure. In this article, we propose a series of equations to evaluate the atomic pressure in the RESPA MTS integration procedure on the basis of its equivalence to the Velocity-Verlet integration procedure with a single time step (STS). The equations guarantee time-reversibility even for the system with holonomic constrants. Furthermore, we generalize the equations to both (i) arbitrary number of inner time steps and (ii) arbitrary number of force components (RESPA levels). The atomic pressure calculated by our equations with the MTS integration shows excellent agreement with the reference value with the STS, whereas pressures calculated using the conventional ad hoc equations deviated from it. Our equations can be extended straightforwardly to the MTS integration algorithm for the isothermal NVT and isothermal-isobaric NPT ensembles. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Levosimendan reduces plasma B-type natriuretic peptide and interleukin 6, and improves central hemodynamics in severe heart failure patients.

PubMed

Kyrzopoulos, Stamos; Adamopoulos, Stamatis; Parissis, John T; Rassias, John; Kostakis, George; Iliodromitis, Efstathios; Degiannis, Dimitrios; Kremastinos, Dimitrios Th

2005-03-30

Plasma B-type natriuretic peptide (BNP) and interleukin 6 (IL-6) levels have recently been demonstrated as significant neurohormonal markers associated with the progression of chronic heart failure (CHF). Additionally, clinical studies have shown that the calcium sensitizer, levosimendan, beneficially affects the central hemodynamics of CHF patients and improves their long-term prognosis. This study investigates whether levosimendan-induced hemodynamic improvement of CHF patients is related to the respective changes of NT-proBNP and IL-6 levels. Circulating levels of NT-pro BNP and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA) in 12 patients with decompensated advanced CHF at baseline, immediately after the end of a 24-h levosimendan infusion and 72 h after the initiation of treatment. Hemodynamic parameters of patients (pulmonary wedge and pulmonary artery pressure (PAP), systemic and pulmonary vascular resistance (PVR), stroke volume, and cardiac output and index) were also monitored during the same period. NT-proBNP and IL-6 levels were significantly reduced in severe CHF patients within 72 h after the initiation of levosimendan treatment (p<0.01 and p<0.05, respectively). A significant reduction of pulmonary wedge (p<0.01) and artery pressure values (p<0.05) was also found during the same period. A good correlation between the levosimendan-induced changes in NT-proBNP levels and the respective reduction of pulmonary wedge pressure (r(s)=0.65, p<0.05) was observed. Our results indicate that changes of NT-pro BNP and IL-6 levels may be useful biochemical markers related with the levosimendan-induced improvement in central hemodynamics and the clinical status of decompensated advanced CHF patients.

Cardiopulmonary and arterial baroreceptor unloading during passive hyperthermia does not contribute to hyperthermia-induced hyperventilation.

PubMed

Lucas, Rebekah A I; Pearson, James; Schlader, Zachary J; Crandall, Craig G

2015-11-01

What is the central question of this study? Does baroreceptor unloading during passive hyperthermia contribute to increases in ventilation and decreases in end-tidal carbon dioxide during that exposure? What is the main finding and its importance? Hyperthermic hyperventilation is not mitigated by expanding central blood volume and reloading the cardiopulmonary baroreceptors via rapid saline infusion or by reloading the arterial baroreceptors via phenylephrine administration. The absence of a reduction in ventilation upon reloading the baroreceptors to pre-hyperthermic levels indicates that cardiopulmonary and arterial baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. This study tested the hypothesis that baroreceptor unloading during passive hyperthermia contributes to increases in ventilation and decreases in end-tidal partial pressure of carbon dioxide (P ET ,CO2) during that exposure. Two protocols were performed, in which healthy subjects underwent passive hyperthermia (increasing intestinal temperature by ∼1.8°C) to cause a sustained increase in ventilation and reduction in P ET ,CO2. Upon attaining hyperthermic hyperventilation, in protocol 1 (n = 10; three females) a bolus (19 ± 2 ml kg(-1) ) of warm (∼38°C) isotonic saline was rapidly (5-10 min) infused intravenously to restore reductions in central venous pressure, whereas in protocol 2 (n = 11; five females) phenylephrine was infused intravenously (60-120 μg min(-1) ) to return mean arterial pressure to normothermic levels. In protocol 1, hyperthermia increased ventilation (by 2.2 ± 1.7 l min(-1) , P < 0.01), while reducing P ET ,CO2 (by 4 ± 3 mmHg, P = 0.04) and central venous pressure (by 5 ± 1 mmHg, P <0.01). Saline infusion increased central venous pressure by 5 ± 1 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or P ET ,CO2 (P > 0.05). In protocol 2, hyperthermia increased ventilation (by 5.0 ± 2.7 l min(-1) , P <0.01) and reduced P ET ,CO2 (by 5 ± 2 mmHg, P < 0.01) and mean arterial pressure (by 9 ± 7 mmHg, P <0.01). Phenylephrine infusion increased mean arterial pressure by 12 ± 3 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or P ET ,CO2 (P > 0.05). The absence of a reduction in ventilation upon reloading the cardiopulmonary and arterial baroreceptors to pre-hyperthermic levels indicates that baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Neuroendocrine and Inflammatory Responses to Losartan and Continuous Positive Airway Pressure in Patients with Hypertension and Obstructive Sleep Apnea. A Randomized Controlled Trial.

PubMed

Thunström, Erik; Manhem, Karin; Yucel-Lindberg, Tülay; Rosengren, Annika; Lindberg, Caroline; Peker, Yüksel

2016-11-01

Blood pressure reduction in response to antihypertensive agents is less for patients with obstructive sleep apnea (OSA). Increased sympathetic and inflammatory activity, as well as alterations in the renin-angiotensin-aldosterone system, may play a role in this context. To address the cardiovascular mechanisms involved in response to an angiotensin II receptor antagonist, losartan, and continuous positive airway pressure (CPAP) as add-on treatment for hypertension and OSA. Newly diagnosed hypertensive patients with or without OSA (allocated in a 2:1 ratio for OSA vs. no OSA) were treated with losartan 50 mg daily during a 6-week two-center, open-label, prospective, case-control, parallel-design study. In the second 6-week, sex-stratified, open-label, randomized, parallel-design study, all subjects with OSA continued to receive losartan and were randomly assigned to either CPAP as add-on therapy or to no CPAP (1:1 ratio for CPAP vs. no CPAP). Study subjects without OSA were followed in parallel while they continued to take losartan. Blood samples were collected at baseline, after 6 weeks, and after 12 weeks for analysis of renin, aldosterone, noradrenaline, adrenaline, and inflammatory markers. Fifty-four patients with OSA and 35 without OSA were included in the first 6-week study. Losartan significantly increased renin levels and reduced aldosterone levels in the group without OSA. There was no significant decrease in aldosterone levels among patients with OSA. Add-on CPAP treatment tended to lower aldosterone levels, but reductions were more pronounced in measures of sympathetic activity. No significant changes in inflammatory markers were observed following treatment with losartan and CPAP. Hypertensive patients with OSA responded to losartan treatment with smaller reductions in aldosterone compared with hypertensive patients without OSA. Sympathetic system activity seemed to respond primarily to add-on CPAP treatment in patients with newly discovered hypertension and OSA. Clinical trial registered with www.clinicaltrials.gov (NCT00701428).

Ankle joint pressure changes in a pes cavovarus model: supramalleolar valgus osteotomy versus lateralizing calcaneal osteotomy.

PubMed

Schmid, Timo; Zurbriggen, Sebastian; Zderic, Ivan; Gueorguiev, Boyko; Weber, Martin; Krause, Fabian G

2013-09-01

A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared. A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors. A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen. LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was seen. In patients with fixed cavovarus feet, both SMOT and LCOT provided equally good redistribution of elevated ankle joint contact forces. Increasing the amount of displacement did not seem to equally improve the joint pressures. The site of osteotomy could therefore be chosen on the basis of surgeon's preference, simplicity, or local factors in case of more complex reconstructions.

Acute effects of traditional Thai massage on cortisol levels, arterial blood pressure and stress perception in academic stress condition: A single blind randomised controlled trial.

PubMed

Bennett, Surussawadi; Bennett, Michael John; Chatchawan, Uraiwon; Jenjaiwit, Patcharaporn; Pantumethakul, Rungthip; Kunhasura, Soontorn; Eungpinichpong, Wichai

2016-04-01

Traditional Thai massage (TTM) has been applied widely to promote relaxation. However, there is little evidence to support its efficacy on academic stress. A randomised controlled trial was performed to examine the acute effects of TTM on cortisol level, blood pressure, heart rate and stress perception in academic stress. This prospective trial included 36 physiotherapy students with a self perceived stress score of between 3 and 5. They were randomly allocated into the TTM (18 people) group or the control group (18 people). Saliva cortisol level, blood pressure, heart rate and stress perception rating were measured before and after the intervention. Both groups showed a significant reduction in cortisol level and heart rate when compared with baseline (p < 0.001). There were no significant differences in cortisol level between the two groups. The results suggest the need for further study into other possible physiological effects on stress of TTM. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling subharmonic response from contrast microbubbles as a function of ambient static pressure

PubMed Central

Katiyar, Amit; Sarkar, Kausik; Forsberg, Flemming

2011-01-01

Variation of subharmonic response from contrast microbubbles with ambient pressure is numerically investigated for non-invasive monitoring of organ-level blood pressure. Previously, several contrast microbubbles both in vitro and in vivo registered approximately linear (5–15 dB) subharmonic response reduction with 188 mm Hg change in ambient pressure. In contrast, simulated subharmonic response from a single microbubble is seen here to either increase or decrease with ambient pressure. This is shown using the code BUBBLESIM for encapsulated microbubbles, and then the underlying dynamics is investigated using a free bubble model. The ratio of the excitation frequency to the natural frequency of the bubble is the determining parameter—increasing ambient pressure increases natural frequency thereby changing this ratio. For frequency ratio below a lower critical value, increasing ambient pressure monotonically decreases subharmonic response. Above an upper critical value of the same ratio, increasing ambient pressure increases subharmonic response; in between, the subharmonic variation is non-monotonic. The precise values of frequency ratio for these three different trends depend on bubble radius and excitation amplitude. The modeled increase or decrease of subharmonic with ambient pressure, when one happens, is approximately linear only for certain range of excitation levels. Possible reasons for discrepancies between model and previous experiments are discussed. PMID:21476688

Compartment syndromes

NASA Technical Reports Server (NTRS)

Mubarak, S. J.; Pedowitz, R. A.; Hargens, A. R.

1989-01-01

The compartment syndrome is defined as a condition in which high pressure within a closed fascial space (muscle compartment) reduces capillary blood perfusion below the level necessary for tissue viability'. This condition occurs in acute and chronic (exertional) forms, and may be secondary to a variety of causes. The end-result of an extended period of elevated intramuscular pressure may be the development of irreversible tissue injury and Volkmann's contracture. The goal of treatment of the compartment syndrome is the reduction of intracompartmental pressure thus facilitating reperfusion of ischaemic tissue and this goal may be achieved by decompressive fasciotomy. Controversy exists regarding the critical pressure-time thresholds for surgical decompression and the optimal diagnostic methods of measuring intracompartmental pressures. This paper will update and review some current knowledge regarding the pathophysiology, aetiology, diagnosis, and treatment of the acute compartment syndrome.

Experimental clean combustor program, phase 1

NASA Technical Reports Server (NTRS)

Bahr, D. W.; Gleason, C. C.

1975-01-01

Full annular versions of advanced combustor designs, sized to fit within the CF6-50 engine, were defined, manufactured, and tested at high pressure conditions. Configurations were screened, and significant reductions in CO, HC, and NOx emissions levels were achieved with two of these advanced combustor design concepts. Emissions and performance data at a typical AST cruise condition were also obtained along with combustor noise data as a part of an addendum to the basic program. The two promising combustor design approaches evolved in these efforts were the Double Annular Combustor and the Radial/Axial Combustor. With versions of these two basic combustor designs, CO and HC emissions levels at or near the target levels were obtained. Although the low target NOx emissions level was not obtained with these two advanced combustor designs, significant reductions were relative to the NOx levels of current technology combustors. Smoke emission levels below the target value were obtained.

[Physical activity and blood pressure. An epidemiological brief review of primary preventive effects of physical exercise activities].

PubMed

Marti, B

1992-04-07

The relation between physical exercise and blood pressure as well as the risk of hypertension has been investigated extensively during recent years. Cross-sectional studies on exercising and physically fit subjects have shown that endurance capacity (i. e. maximum aerobic capacity) is inversely related to resting blood pressure. However, not all physical activities are associated with lower blood pressure levels; e.g. swimming, weight lifting and competitive cross-country skiing were found to be related to elevated blood pressure values in some studies. Population-based investigations reveal a trend towards lower blood pressure values in physically habitually active persons, with the difference between active and inactive subjects not exceeding 5 mmHg. Three epidemiological cohort studies have consistently demonstrated that sedentary, unfit persons have a 20 to 50% higher prospective risk of hypertension, as compared to exercising, physically fit persons. Some intervention studies with normotensive subjects show a reduction in resting blood pressure of 5 to 10 mmHg at best after several months of aerobic training, while other studies show no effect. At least two factors could be responsible for these somewhat inconsistent observations: 1. exercise intensity may act as an 'effect modifier', since vigorous to maximally hard exercise rather increases than lowers resting blood pressure, 2. in statistical analysis on the effect of physical training on blood pressure, it is crucial whether concomitant changes in body weight and body composition are taken into account: any adjustment for changes in body composition will substantially reduce the magnitude of 'exercise-induced' reductions in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic Effect of Captopril, Pentoxifylline, and Cordyceps Sinensis in Pre-Hepatic Portal Hypertensive Rats

PubMed Central

Ahmed, Ahmed F.; El-Maraghy, Nabila N.; Ghaney, Rasha H. Abdel; Elshazly, Shimaa M.

2012-01-01

Background/Aim: Portal hypertension is an important and potentially fatal complication of liver disease whereby cellular and fibrotic alterations manifest to increase portal venous pressure. The aim of this study is to investigate the effect of captopril, pentoxifylline (PTX), and cordyceps sinensis in pre-hepatic portal hypertensive rats. Settings and Design: Wister male rats were divided at random into 3 main groups: the first group: control rats. The second group: sham-operated rats and the third group: prehepatic portal hypertensive rats (PHPHT) induced by regulated pre-hepatic portal vein ligation. After 14 days, Group 3 was subdivided into 5 subgroups. Subgroup (1): portal vein-ligated (PVL) was killed at once; Subgroup (2): received distilled water for 30 days (untreated PVL group); subgroups 3-5 were treated with captopril (60 mg/kg, orally); PTX (100 mg/kg, orally); and C. sinensis (200 mg/kg, orally), respectively, as a single daily dose for 30 days. Patients and Methods: Portal pressure, nitric oxide (NO), antioxidant enzymes, Liver enzymes, and creatinine levels were measured to evaluate the status of the liver state. Results: Portal vein ligation produced significant increments in liver enzymes, NO, creatinine and portal pressure concomitant with significant decrements in glutathione content and superoxide dismutase activity. Treatment with captopril, PTX, and C. sinensis resulted in a significant reduction in liver enzymes, NO, creatinine and portal pressure and observable increase in antioxidant enzymes. Conclusions: captopril, PTX, and C. sinensis have promising effect in controlling PHPHT and reducing hyperdynamic circulatory state through reduction of portal pressure and NO level. PMID:22626797

A physics link between venous stenosis and multiple sclerosis.

PubMed

Tucker, Trevor W

2011-12-01

This paper hypothesizes that a stenosis or obstruction at a lower extremity of an internal jugular vein (IJV) would, in accordance with the physics of fluid dynamics, cause a standing pressure wave within the vein. This pressure wave would possess regions of large pressure fluctuations and other regions of relatively little fluctuation which also have substantially lower peak pressure values. If the wavelength of the hypothesized pressure wave is comparable to the distance from the obstruction to the venule end of the capillary bed, then a region of high pressure fluctuation would exist at the venules. Depending on the degree of obstruction, the pressure fluctuations at the venules of the capillary bed would be substantially greater than those that would exist in a healthy unobstructed vein. This increase in blood pressure fluctuation located at the venule end of the capillary bed, which would be equivalent to local hypertension, is predicted to reduce the pressure drop across the bed which, in turn, would reduce blood flow through the bed in accordance with Darcy's Law. Such a reduction in blood flow through the bed would be accompanied by a reduction in the transfer of oxygen, glucose and other nutrients into the brain tissue in accordance with Fick's Principle. The reduction in oxygen levels in the brain tissue (i.e. hypoxia), would, in turn, be associated with increased fatigue and decreased mental acuity in the subject patient. Also the deprivation of oxygen in the brain tissue may result in the death of oligodendrocyte cells, which, in turn would result in the deterioration of the myelin surrounding the brain's neural axons. In addition, the paper also predicts that, in cases of extreme obstruction, the predicted localized hypertension at the venule end of the capillary bed may be sufficiently high to cause a localized disruption in the blood-brain barrier. Such a disruption of the blood-brain barrier could then allow the migration of leukocytes (auto-immune attack cells), from the blood into the brain tissue, enabling them to attack myelin, which has degenerated or deteriorated from the reduction in repair function normally provided by oligodendrocyte cells. Such leukocyte attack on myelin has long been associated with multiple sclerosis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Jet Noise Reduction Potential from Emerging Variable Cycle Technologies

NASA Technical Reports Server (NTRS)

Henderson, Brenda; Bridges, James; Wernet, Mark

2012-01-01

Acoustic and flow-field experiments were conducted on exhaust concepts for the next generation supersonic, commercial aircraft. The concepts were developed by Lockheed Martin (LM), Rolls-Royce Liberty Works (RRLW), and General Electric Global Research (GEGR) as part of an N+2 (next generation forward) aircraft system study initiated by the Supersonics Project in NASA s Fundamental Aeronautics Program. The experiments were conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center. The exhaust concepts utilized ejectors, inverted velocity profiles, and fluidic shields. One of the ejector concepts was found to produce stagnant flow within the ejector and the other ejector concept produced discrete-frequency tones that degraded the acoustic performance of the model. The concept incorporating an inverted velocity profile and fluid shield produced overall-sound-pressure-level reductions of 6 dB relative to a single stream nozzle at the peak jet noise angle for some nozzle pressure ratios. Flow separations in the nozzle degraded the acoustic performance of the inverted velocity profile model at low nozzle pressure ratios.

Jet Noise Reduction Potential From Emerging Variable Cycle Technologies

NASA Technical Reports Server (NTRS)

2012-01-01

Acoustic and flow-field experiments were conducted on exhaust concepts for the next generation supersonic, commercial aircraft. The concepts were developed by Lockheed Martin (LM), Rolls-Royce Liberty Works (RRLW), and General Electric Global Research (GEGR) as part of an N+2 (next generation forward) aircraft system study initiated by the Supersonics Project in NASA s Fundamental Aeronautics Program. The experiments were conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center. The exhaust concepts utilized ejectors, inverted velocity profiles, and fluidic shields. One of the ejector concepts was found to produce stagnant flow within the ejector and the other ejector concept produced discrete-frequency tones that degraded the acoustic performance of the model. The concept incorporating an inverted velocity profile and fluid shield produced overall-sound-pressure-level reductions of 6 dB relative to a single stream nozzle at the peak jet noise angle for some nozzle pressure ratios. Flow separations in the nozzle degraded the acoustic performance of the inverted velocity profile model at low nozzle pressure ratios.

Effect of Turkish classical music on blood pressure: a randomized controlled trial in hypertensive elderly patients.

PubMed

Bekiroğlu, Tansel; Ovayolu, Nimet; Ergün, Yusuf; Ekerbiçer, Hasan Çetin

2013-06-01

Existing studies suggest that music therapy can have favorable effects on hypertension and anxiety. We therefore set out to investigate the effect of Turkish classical music. To investigate whether Turkish classical music has positive effects on blood pressures and anxiety levels in elderly patients. This was a randomized controlled trial performed on 60 hypertensive patients living in a local elderly home in Adana, Turkey. Following the completion of a socio-demographic form for each patient, Hamilton anxiety scale was applied. Thereafter, the subjects were randomly divided into two equal-size groups and were allowed to either listen to Turkish classical music (music therapy group) or have a resting period (control group) for 25 min. The primary and secondary outcome measures were blood pressure and Hamilton anxiety scale scores, respectively. The mean reduction in systolic blood pressure was 13.00 mmHg in the music therapy group and 6.50 mmHg in the control group. The baseline adjusted between treatment group difference was not statistically significant (95% CI 6.80-9.36). The median reductions in diastolic blood pressures were 10 mmHg both in the music therapy and control groups. The between treatment group difference was not statistically significant (Mann-Whitney U test, P = 0.839). The mean reduction in HAMA-A was 1.63 in the music therapy group and 0.77 in the control group. The baseline adjusted between treatment group difference was not statistically significant (95% CI 0.82-1.92). The study demonstrated that both Turkish classical music and resting alone have positive effects on blood pressure in patients with hypertension. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Supraglottic Effect of a Reduction in Expiratory Mask Pressure During Continuous Positive Airway Pressure

PubMed Central

Masdeu, Maria J.; Patel, Amit V.; Seelall, Vijay; Rapoport, David M.; Ayappa, Indu

2012-01-01

Study Objectives: Patients with obstructive sleep apnea may have difficulty exhaling against positive pressure, hence limiting their acceptance of continuous positive airway pressure (CPAP). C-Flex is designed to improve comfort by reducing pressure in the mask during expiration proportionally to expiratory airflow (3 settings correspond to increasing pressure changes). When patients use CPAP, nasal resistance determines how much higher supraglottic pressure is than mask pressure. We hypothesized that increased nasal resistance results in increased expiratory supraglottic pressure swings that could be mitigated by the effects of C-Flex on mask pressure. Design: Cohort study. Setting: Sleep center. Participants: Seventeen patients with obstructive sleep apnea/hypopnea syndrome and a mechanical model of the upper airway. Interventions: In patients on fixed CPAP, CPAP with different C-Flex levels was applied multiple times during the night. In the model, 2 different respiratory patterns and resistances were tested. Measurements and Results: Airflow, expiratory mask, and supraglottic pressures were measured on CPAP and on C-Flex. Swings in pressure during expiration were determined. On CPAP, higher nasal resistance produced greater expiratory pressure swings in the supraglottis in the patients and in the model, as expected. C-Flex 3 produced expiratory drops in mask pressure (range −0.03 to −2.49 cm H2O) but mitigated the expira-tory pressure rise in the supraglottis only during a sinusoidal respiratory pattern in the model. Conclusions: Expiratory changes in mask pressure induced by C-Flex did not uniformly transmit to the supraglottis in either patients with obstructive sleep apnea on CPAP or in a mechanical model of the upper airway with fixed resistance. Data suggest that the observed lack of expiratory drop in supraglottic pressure swings is related to dynamics of the C-Flex algorithm. Citation: Masdeu MJ; Patel AV; Seelall V; Rapoport DM; Ayappa I. The supraglottic effect of a reduction in expiratory mask pressure during continuous positive airway pressure. SLEEP 2012;35(2):263-272. PMID:22294817

Mechanism of reduction of mitral regurgitation with vasodilator therapy.

PubMed

Yoran, C; Yellin, E L; Becker, R M; Gabbay, S; Frater, R W; Sonnenblick, E H

1979-04-01

Acute mitral regurgitation was produced in six open chest dogs by excising a portion of the anterior valve leaflet. Electromagnetic flow probes were placed in the left atrium around the mitral anulus and in the ascending aorta to determine phasic left ventricular filling volume, regurgitant volume and stroke volume. The systolic pressure gradient was calculated from simultaneously measured high fidelity left atrial and left ventricular pressures. The effective mitral regurgitant orifice area was calculated from Gorlin's hydraulic equation. Infusion of nitroprusside resulted in a significant reduction in mitral regurgitation. No significant change occurred in the systolic pressure gradient between the left ventricle and the left atrium because both peak left ventricular pressure and left atrial pressure were reduced. The reduction of mitral regurgitation was largely due to reduction in the size of the mitral regurgitant orifice. Reduction of ventricular volume rather than the traditional concept of reduction of impedance of left ventricular ejection may explain the effects of vasodilators in reducing mitral regurgitation.

Anxiety as a Predictor of Behavioral Therapy Outcome for Cancer Chemotherapy Patients.

ERIC Educational Resources Information Center

Carey, Michael P.; Burish, Thomas G.

1985-01-01

Determined if baseline anxiety levels are predictive of outcome on treatments associated with cancer chemotherapy. Results indicated low-anxiety patients reported less anxiety and depression before behavioral training but nonetheless exhibited significantly greater reductions in anxiety, depression, and diastolic blood pressure after training.…

Hearing with an atympanic ear: good vibration and poor sound-pressure detection in the royal python, Python regius.

PubMed

Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian; Madsen, Peter Teglberg

2012-01-15

Snakes lack both an outer ear and a tympanic middle ear, which in most tetrapods provide impedance matching between the air and inner ear fluids and hence improve pressure hearing in air. Snakes would therefore be expected to have very poor pressure hearing and generally be insensitive to airborne sound, whereas the connection of the middle ear bone to the jaw bones in snakes should confer acute sensitivity to substrate vibrations. Some studies have nevertheless claimed that snakes are quite sensitive to both vibration and sound pressure. Here we test the two hypotheses that: (1) snakes are sensitive to sound pressure and (2) snakes are sensitive to vibrations, but cannot hear the sound pressure per se. Vibration and sound-pressure sensitivities were quantified by measuring brainstem evoked potentials in 11 royal pythons, Python regius. Vibrograms and audiograms showed greatest sensitivity at low frequencies of 80-160 Hz, with sensitivities of -54 dB re. 1 m s(-2) and 78 dB re. 20 μPa, respectively. To investigate whether pythons detect sound pressure or sound-induced head vibrations, we measured the sound-induced head vibrations in three dimensions when snakes were exposed to sound pressure at threshold levels. In general, head vibrations induced by threshold-level sound pressure were equal to or greater than those induced by threshold-level vibrations, and therefore sound-pressure sensitivity can be explained by sound-induced head vibration. From this we conclude that pythons, and possibly all snakes, lost effective pressure hearing with the complete reduction of a functional outer and middle ear, but have an acute vibration sensitivity that may be used for communication and detection of predators and prey.

Cardiopulmonary and Metabolic Effects of Yoga in Healthy Volunteers

PubMed Central

Divya, T Satheesh; Vijayalakshmi, MT; Mini, K; Asish, K; Pushpalatha, M; Suresh, Varun

2017-01-01

Background: Yoga the spiritual union of mind with the divine intelligence of the universe aims to liberate a human being from conflicts of body–mind duality. Beneficial cardiovascular and pulmonary effects of yoga are in par with aerobic exercise, even amounting to replace the exercise model. We conducted an interventional study in healthy volunteers, to analyze the impact of short-term yoga training on cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests. Materials and Methods: A sample of fifty new recruits attending the district yoga center was subject to 75 min yoga practice a day for 41 days. Basal values of cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests were recorded before yoga training and were reassessed for postyoga changes after 41 days. Results: After yoga practice there was a significant reduction in the resting heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure of the participants. Effects on autonomic function tests were variable and inconclusive. There was a significant increase in forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow rate after yoga. A significant reduction in body mass index was observed. Effects on metabolic parameters were promising with a significant reduction in fasting blood sugar level, serum total cholesterol, serum triglycerides serum low-density lipoprotein levels, and significant increase in high-density lipoprotein. There was no significant change in thyroid function tests after yoga. Conclusion: Short-term yoga practice has no effect on thyroid functions. Yoga practice was found beneficial in maintaining physiological milieu pertaining to cardiovascular and other metabolic parameters. PMID:29422741

Cardiopulmonary and Metabolic Effects of Yoga in Healthy Volunteers.

PubMed

Divya, T Satheesh; Vijayalakshmi, M T; Mini, K; Asish, K; Pushpalatha, M; Suresh, Varun

2017-01-01

Yoga the spiritual union of mind with the divine intelligence of the universe aims to liberate a human being from conflicts of body-mind duality. Beneficial cardiovascular and pulmonary effects of yoga are in par with aerobic exercise, even amounting to replace the exercise model. We conducted an interventional study in healthy volunteers, to analyze the impact of short-term yoga training on cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests. A sample of fifty new recruits attending the district yoga center was subject to 75 min yoga practice a day for 41 days. Basal values of cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests were recorded before yoga training and were reassessed for postyoga changes after 41 days. After yoga practice there was a significant reduction in the resting heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure of the participants. Effects on autonomic function tests were variable and inconclusive. There was a significant increase in forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow rate after yoga. A significant reduction in body mass index was observed. Effects on metabolic parameters were promising with a significant reduction in fasting blood sugar level, serum total cholesterol, serum triglycerides serum low-density lipoprotein levels, and significant increase in high-density lipoprotein. There was no significant change in thyroid function tests after yoga. Short-term yoga practice has no effect on thyroid functions. Yoga practice was found beneficial in maintaining physiological milieu pertaining to cardiovascular and other metabolic parameters.

Antihypertensive treatment and stroke prevention: are angiotensin receptor blockers superior to other antihypertensive agents?

PubMed

Armario, Pedro; de la Sierra, Alejandro

2009-06-01

Stroke remains a common vascular event with high mortality and morbidity. After heart disease, stroke is the second leading cause of death worldwide in adult persons. Silent or subclinical stroke is likely to occur with even greater frequency than clinical stroke and increases the risk of subsequent cerebrovascular events. Hypertension is by far the single most important controllable risk factor for stroke. The relationship between blood pressure (BP) and stroke mortality is strong, linear, and continuous in subjects with levels of BP higher than 115/75 mm Hg. Blood pressure reduction by antihypertensive treatment is clearly efficacious in the prevention of stroke (both primary and secondary). Although meta-analyses suggest that BP reduction, per se, is the most important determinant for stroke risk reduction, the question is if specific classes of antihypertensive drugs offer special protection against stroke is still controversial. Some studies have suggested that angiotensin receptors blockers (ARBs) appear to offer additional protection against stroke. This has been hypothesized in studies in hypertensives, such as LIFE and SCOPE, and especially in the only comparative trial focused on secondary stroke prevention. In the MOSES trial, the comparison of eprosartan versus nitrendipine in patients with a previous stroke resulted, despite a similar BP reduction, in a significant reduction in the primary composite endpoint of total mortality plus cardiovascular and cerebrovascular events, including recurrent events. These results may suggest a blood pressure-independent effect of ARBs, which can be mediated through several mechanisms, including their ability to counteract other markers of target organ damage, but also through a direct neuroprotective effect.

Effect of two different hypocaloric diets in transaminases and insulin resistance in nonalcoholic fatty liver disease and obese patients.

PubMed

de Luis, D A; Aller, R; Izaola, O; Gonzalez Sagrado, M; Conde, R

2010-01-01

The aim of our study was to examine the changes in hypertransaminasemia after weight reduction in obese patients with and without NAFLD and the relation with insulin resistance. A population of 162 obese patients was randomly allocated to two groups: a) diet I (low fat) and b) diet II (low carbohydrate), dieting along 3 months. Patients were classified as group I (n=112) when serum ALT activity was normal or group II (NAFLD, n=30) when serum ALT activity was (>or=43 UI/L). In control group with diet I, BMI, weight, fat mass, waist to hip ratio, waist circumference, systolic pressure, total cholesterol, LDL cholesterol, HOMA and insulin levels decreased. In NAFLD group with diet I improved the same parameters and glucose, triglycerides, ALT, AST, gamaglutamine transferase levels, too. In control group with diet II, BMI, weight, fat mass, waist to hip ratio, waist circumference, systolic pressure, total cholesterol, LDL cholesterol, HOMA and insulin levels decreased. In NAFLD group with diet II improved the same parameters and glucose, triglycerides, ALT and gamaglutamine transferase levels, without statistical changes in AST. We showed that weight reduction secondary to two hypocaloric diets was associated with improvement in hipertransaminasemia and insulin resistance in NAFLD patients.

Structural, functional and blood perfusion changes in the rat retina associated with elevated intraocular pressure, measured simultaneously with a combined OCT+ERG system

PubMed Central

Tan, Bingyao; MacLellan, Benjamin; Mason, Erik

2018-01-01

Acute elevation of intraocular pressure (IOP) to ischemic and non-ischemic levels can cause temporary or permanent changes in the retinal morphology, function and blood flow/blood perfusion. Previously, such changes in the retina were assessed separately with different methods in clinical studies and animal models. In this study, we used a combined OCT+ ERG system in combination with Doppler OCT and OCT angiography (OCTA) imaging protocols, in order to evaluate simultaneously and correlate changes in the retinal morphology, the retinal functional response to visual stimulation, and the retinal blood flow/blood perfusion, associated with IOP elevation to ischemic and non-ischemic levels in rats. Results from this study suggest that the inner retina responds faster to IOP elevation to levels greater than 30 mmHg with significant reduction of the total retinal blood flow (TRBF), decrease of the capillaries’ perfusion and reduction of the ON bipolar cells contribution to the ERG traces. Furthermore, this study showed that ischemic levels of IOP elevation cause an additional significant decrease in the ERG photoreceptor response in the posterior retina. Thirty minutes after IOP normalization, retinal morphology, blood flow and blood perfusion recovered to baseline values, while retinal function did not recover completely. PMID:29509807

Comparative effectiveness of quality improvement interventions for pressure ulcer prevention in academic medical centers in the United States.

PubMed

Padula, William V; Makic, Mary Beth F; Mishra, Manish K; Campbell, Jonathan D; Nair, Kavita V; Wald, Heidi L; Valuck, Robert J

2015-06-01

Prevention of pressure ulcers, one of the hospital-acquired conditions (HACs) targeted by the 2008 nonpayment policy of the Centers for Medicare & Medicaid Services (CMS), is a critical issue. This study was conducted to determine the comparative effectiveness of quality improvement (QI) interventions associated with reduced hospital-acquired pressure ulcer (HAPU) rates. In an quasi-experimental design, interrupted time series analyses were conducted to determine the correlation between HAPU incidence rates and adoption of QI interventions. Among University HealthSystem Consortium hospitals, 55 academic medical centers were surveyed from September 2007 through February 2012 for adoption patterns of QI interventions for pressure ulcer prevention, and hospital-level data for 5,208 pressure ulcer cases were analyzed. Between- and within-hospital reduction significance was tested with t-tests post-CMS policy intervention. Fifty-three (96%) of the 55 hospitals used QI interventions for pressure ulcer prevention. The effect size analysis identified five effective interventions that each reduced pressure ulcer rates by greater than 1 case per 1,000 patient discharges per quarter: leadership initiatives, visual tools, pressure ulcer staging, skin care, and patient nutrition. The greatest reductions in rates occurred earlier in the adoption process (p<.05). Five QI interventions had clinically meaningful associations with reduced stage III and IV HAPU incidence rates in 55 academic medical centers. These QI interventions can be used in support of an evidence-based prevention protocol for pressure ulcers. Hospitals can not only use these findings from this study as part of a QI bundle for preventing HAPUs.

Ischemia causes muscle fatigue

NASA Technical Reports Server (NTRS)

Murthy, G.; Hargens, A. R.; Lehman, S.; Rempel, D. M.

2001-01-01

The purpose of this investigation was to determine whether ischemia, which reduces oxygenation in the extensor carpi radialis (ECR) muscle, causes a reduction in muscle force production. In eight subjects, muscle oxygenation (TO2) of the right ECR was measured noninvasively and continuously using near infrared spectroscopy (NIRS) while muscle twitch force was elicited by transcutaneous electrical stimulation (1 Hz, 0.1 ms). Baseline measurements of blood volume, muscle oxygenation and twitch force were recorded continuously, then a tourniquet on the upper arm was inflated to one of five different pressure levels: 20, 40, 60 mm Hg (randomized order) and diastolic (69 +/- 9.8 mm Hg) and systolic (106 +/- 12.8 mm Hg) blood pressures. Each pressure level was maintained for 3-5 min, and was followed by a recovery period sufficient to allow measurements to return to baseline. For each respective tourniquet pressure level, mean TO2 decreased from resting baseline (100% TO2) to 99 +/- 1.2% (SEM), 96 +/- 1.9%, 93 +/- 2.8%, 90 +/- 2.5%, and 86 +/- 2.7%, and mean twitch force decreased from resting baseline (100% force) to 99 +/- 0.7% (SEM), 96 +/- 2.7%, 93 +/- 3.1%, 88 +/- 3.2%, and 86 +/- 2.6%. Muscle oxygenation and twitch force at 60 mm Hg tourniquet compression and above were significantly lower (P < 0.05) than baseline value. Reduced twitch force was correlated in a dose-dependent manner with reduced muscle oxygenation (r = 0.78, P < 0.001). Although the correlation does not prove causation, the results indicate that ischemia leading to a 7% or greater reduction in muscle oxygenation causes decreased muscle force production in the forearm extensor muscle. Thus, ischemia associated with a modest decline in TO2 causes muscle fatigue.

Cardiac autonomic tone during trandolapril-irbesartan low-dose combined therapy in hypertension: a pilot project.

PubMed

Franchi, F; Lazzeri, C; Foschi, M; Tosti-Guerra, C; Barletta, G

2002-08-01

Pharmacological and clinical studies on the effects of angiotensin-converting enzyme (ACE) inhibitors support the idea of a central role played Angiotensin II which is able to cause cardiovascular and renal diseases also independently of its blood pressure elevating effects. The present investigation was aimed at evaluating the effect(s) of three different pharmacological regimens on both blood pressure and sympathetic drive in uncomplicated essential hypertension, by means of blood pressure laboratory measurements and ambulatory monitoring, 24-h heart rate variability and plasma noradrenaline levels. Thus, an ACE-inhibitor monotherapy (trandolapril, 2 mg/day), an AT(1)-receptor antagonist monotherapy (irbesartan, 300 mg/day), their low-dose combination (0.5 mg/day plus 150 mg/day, respectively) and placebo were given, in a randomised, single-blind, crossover fashion for a period of 3 weeks each to 12 mild essential hypertensives. Power spectral analysis (short recordings) and noradrenaline measurements were also performed in the supine position and after a postural challenge (60 degrees head-up tilting test: HUT). The low-dose combination therapy induced the greatest reduction in LF component and in LF/HF ratio, both in the resting and tilted positions, as well as in blood pressure. However, the physiological autonomic response to HUT was maintained. Noradrenaline plasma levels were lower after the combined therapy than after each drug alone. Our data demonstrate that in mild and uncomplicated essential hypertension, the chronic low-dose combination therapy with an ACE-inhibitor and an AT(1)-antagonist is more effective than the recommended full-dose monotherapy with either drug in influencing the autonomic regulation of the heart, suggesting a relative reduction in sympathetic drive both at cardiac and systemic levels.

A low-dimensional approach to closed-loop control of a Mach 0.6 jet

NASA Astrophysics Data System (ADS)

Low, Kerwin R.; Berger, Zachary P.; Kostka, Stanislav; ElHadidi, Basman; Gogineni, Sivaram; Glauser, Mark N.

2013-04-01

Simultaneous time-resolved measurements of the near-field hydrodynamic pressure field, 2-component streamwise velocity field, and far-field acoustics are taken for an un-heated, axisymmetric Mach 0.6 jet in co-flow. Synthetic jet actuators placed around the periphery of the nozzle lip provide localized perturbations to the shear layer. The goal of this study was to develop an understanding of how the acoustic nature of the jet responds to unsteady shear layer excitation, and subsequently how this can be used to reduce the far-field noise. Review of the cross-correlations between the most energetic low-order spatial Fourier modes of the pressure and the far-field region reveals that mode 0 has a strong correlation and mode 1 has a weak correlation with the far-field. These modes are emulated with the synthetic jet array and used as drivers of the developing shear layer. In open loop forcing configurations, there is energy transfer among spatial scales, enhanced mixing, a reconfiguration of the low-dimensional spatial structure, and an increase in the overall sound pressure level (OASPL). In the closed loop configuration, changes to these quantities are more subtle but there is a reduction in the overall fluctuating sound pressure level OASPLf by 1.35 dB. It is argued that this reduction is correlated with the closed loop control feeding back the dynamical low-order information measured in the largest noise producing region.

[POSITIVE END-EXPIRATORY PRESSURE (PEEP) INFLUENCES ON INTRACRANIAL PRESSURE, SYSTEMIC HEMODYNAMICS AND PULMONARY GAS EXCHANGE IN PATIENTS WITH INTRACRANIAl HEMORRHAGE IN CRITICAL STATE].

PubMed

Solodov, A A; Petrikov, S S; Krylov, V V

2016-01-01

Positive end-expiratory pressure is one of the main parameters of respiratory support influencing the gas exchange. However, despite the number ofpositive effects, PEEP can compromise venous outflow from the cranial cavity, increased intracranial pressure, decreased venous return and cardiac output and, consequently, reduced blood pressure and cerebral perfusion. The article presents the results of a survey of 39 patients with intracranial hemorrhage in critical state, undergoing respiratory support with different levels of positive end-expiratory pressure. Increasing of PEEP to 15 cm H2O had no adverse effect on mean arterial pressure, heart rate and cerebral perfusion pressure and led only to an clinical insignificant increase (maximum on 2.4 +/- 5.1 mmHg) in intracranial pressure. The greatest hemodynamic changes were observed with increasing PEEP up to 20 cm H2O in patients with preserved compliance ofthe respiratory system. The instability of cerebral perfusion and intracranial pressure associated with a decrease in cardiac output and preload and the exhaustion of compensatory mechanism of peripheral vascular resistance. High levels of PEEP despite the trend towards Cstat reduction will not lead to an increase in the content of extravascular lung water Thus a gradual increase of PEEP to 15 cm H2O can be safe and effective method of improving pulmonary gas exchange in patients with intracranial hemorrhage in critical state.

Left ventricular function during lower body negative pressure

NASA Technical Reports Server (NTRS)

Ahmad, M.; Blomqvist, C. G.; Mullins, C. B.; Willerson, J. T.

1977-01-01

The response of the human left ventricle to lower body negative pressure (LBNP) and the relation between left ventricular function and hemodynamic response were investigated. Ventricular function curves relating stroke volume to end-diastolic volume were obtained in 12 normal men. Volume data were derived from echocardiographic measurements of left ventricular end-systolic and end-diastolic diameters at rest and during lower body negative pressure (LBNP) at minus 40 mm Hg. End-diastolic volume decreased by 19% and stroke volume by 22%. There were no significant changes in heart rate, arterial blood pressure, or end-systolic volume. Thus, moderate levels of LBNP significantly reduce preload and stroke volume without affecting contractile state. The absence of significant changes in heart rate and arterial blood pressure in the presence of a significant reduction in stroke volume is consistent with an increase in systemic peripheral resistance mediated by low-pressure baroreceptors.

Muscle Sympathetic Nerve Activity During Intense Lower Body Negative Pressure to Presyncope in Humans

DTIC Science & Technology

2009-08-24

frequency rhythms. Arterial pressure oscillations increase with reductions in central blood volume induced by haemorrhage (Guyton & Harris, 1951), head...a finger cuff to record beat-by-beat finger arterial pressure (Finometer Blood Pressure Monitor, TNO-TPD Biomedical Instrumentation, Amsterdam, The...experienced reductions in arterial pressure at presyncope. The lowest blood pressures recorded for each subject are shown in the upper right of each

Effectiveness of Total Contact Orthosis for Plantar Pressure Redistribution in Neuropathic Diabetic Patients During Different Walking Activities.

PubMed

Nouman, Muhammad; Leelasamran, Wipawan; Chatpun, Surapong

2017-08-01

Using a total contact orthosis (TCO) is an effective method to offload in diabetic patients with foot neuropathy. However, the redistribution of peak plantar pressure is mostly observed during level walking, which may differ from other walking activities. The aim of this study was to investigate the plantar pressure from 4 regions of the foot during different walking activities (level walking, ramp ascending, ramp descending, stair ascending, and stair descending) in neuropathic diabetic patients with and without a TCO. Sixteen neuropathic diabetic patients aged 40 to 60 years with calluses and hallux valgus were included in this study and were provided with TCOs made up of multifoam, Plastazote, and microcellular rubber. The plantar pressure and contact area with the TCO and without the TCO were recorded using the Pedar X system during different walking activities. A significant reduction of plantar pressure during different walking activities at the toes and forefoot regions was observed while walking with the TCO compared with walking without the TCO (control condition). Plantar pressure increased at the midfoot region when walking with the TCO, and no significant difference was observed at the hindfoot region between the control and TCO conditions. Furthermore, maximum contact area was observed during level walking with the TCO compared with other walking activities. The TCO significantly reduced and redistributed the peak plantar pressure from the sites where the ulceration rate is higher at the toes and forefoot compared with the other regions of the foot. Therapeutic level II, lesser quality randomized controlled trial.

On the study of wavy leading-edge vanes to achieve low fan interaction noise

NASA Astrophysics Data System (ADS)

Tong, Fan; Qiao, Weiyang; Xu, Kunbo; Wang, Liangfeng; Chen, Weijie; Wang, Xunnian

2018-04-01

The application of wavy leading-edge vanes to reduce a single-stage axial fan noise is numerically studied. The aerodynamic and acoustic performance of the fan is numerically investigated using a hybrid unsteady Reynolds averaged Navier-Stokes (URANS)/acoustic analogy method (Goldstein equations). First, the hybrid URANS/Goldstein method is developed and successfully validated against experiment results. Next, numerical simulations are performed to investigate the noise reduction effects of the wavy leading-edge vanes. The aerodynamic and acoustic performance is assessed for a fan with vanes equipped with two different wavy leading-edge profiles and compared with the performance of conventional straight leading-edge vanes. Results indicate that a fan with wavy leading-edge vanes produces lower interaction noise than the baseline fan without a significant loss in aerodynamic performance. In fact, it is demonstrated that wavy leading-edge vanes have the potential to lead to both aerodynamic and acoustic improvements. The two different wavy leading-edge profiles are shown to successfully reduce the fan tone sound power level by 1.2 dB and 4.3 dB, respectively. Fan efficiency is also improved by about 1% with one of the tested wavy leading-edge profiles. Large eddy simulation (LES) is also performed for a simplified fan stage model to assess the effects of wavy leading-edge vanes on the broadband fan noise. Results indicate that the overall sound power level of a fan can be reduced by about 4 dB with the larger wavy leading-edge profile. Finally, the noise reduction mechanisms are investigated and analysed. It is found that the wavy leading-edge profiles can induce significant streamwise vorticity around the leading-edge protuberances and reduce pressure fluctuations (especially at locations of wavy leading-edge hills) and unsteady forces on the stator vanes. The underlying mechanism of the reduced pressure fluctuations is also discussed by examining the magnitude-squared coherence between the velocity and pressure fluctuations in the vicinity of the noise sources. Moreover, a reduction in the correlation level of the wall pressure fluctuations along the vane leading-edge is observed, as well as destructive phase interference along the vane leading-edge.

Heading in football. Part 3: Effect of ball properties on head response

PubMed Central

Shewchenko, N; Withnall, C; Keown, M; Gittens, R; Dvorak, J

2005-01-01

Objectives: Head impacts from footballs are an essential part of the game but have been implicated in mild and acute neuropsychological impairment. Ball characteristics have been noted in literature to affect the impact response of the head; however, the biomechanics are not well understood. The present study determined whether ball mass, pressure, and construction characteristics help reduce head and neck can impact response. Methods: Head responses under ball impact (6–7 m/s) were measured with a biofidelic numerical human model and controlled human subject trials (n = 3). Three ball masses and four ball pressures were investigated for frontal heading. Further, the effect of ball construction in wet/dry conditions was studied with the numerical model. The dynamic ball characteristics were determined experimentally. Head linear and angular accelerations were measured and compared with injury assessment functions comprising peak values and head impact power. Neck responses were assessed with the numerical model. Results: Ball mass reductions up to 35% resulted in decreased head responses up to 23–35% for the numerical and subject trials. Similar decreases in neck axial and shear responses were observed. Ball pressure reductions of 50% resulted in head and neck response reductions up to 10–31% for the subject trials and numerical model. Head response reductions up to 15% were observed between different ball constructions. The wet condition generally resulted in greater head and neck responses of up to 20%. Conclusion: Ball mass, pressure, and construction can reduce the impact severity to the head and neck. It is foreseeable that the benefits can be extended to players of all ages and skill levels. PMID:16046354

USACE Extreme Sea Levels Advice on Guidance on Procedures to Evaluate and Adapt to Changes in Mean and Extreme Sea Levels.

DTIC Science & Technology

2014-09-09

influences of changes in extreme sea levels as they affect the four mission areas of USACE: storm damage reduction, flood risk mitigation, ecosystems...winds and surface pressure can occur on the scale of the inundation area under investigation, cyclonic climatologies and more sophisticated inundation...Federal and State agencies (particularly the Bureau of Meteorology) providing forecast data (e.g. DIPNR, 2005, Appendix N). In more developed areas of

Inactivation of Vibrio parahaemolyticus in hard clams (Mercanaria mercanaria) by high hydrostatic pressure (HHP) and the effect of HHP on the physical characteristics of hard clam meat.

PubMed

Mootian, Gabriel K; Flimlin, George E; Karwe, Mukund V; Schaffner, Donald W

2013-02-01

Shellfish may internalize dangerous pathogens during filter feeding. Traditional methods of depuration have been found ineffective against certain pathogens. The objective was to explore high hydrostatic pressure (HHP) as an alternative to the traditional depuration process. The effect of HHP on the survival of Vibrio parahaemolyticus in live clams (Mercanaria mercanaria) and the impact of HHP on physical characteristics of clam meat were investigated. Clams were inoculated with up to 7 log CFU/g of a cocktail of V. parahaemolyticus strains via filter feeding. Clams were processed at pressures ranging from 250 to 552 MPa for hold times ranging between 2 and 6 min. Processing conditions of 450 MPa for 4 min and 350 MPa for 6 min reduced the initial concentration of V. parahaemolyticus to a nondetectable level (<10(1) CFU/g), achieving >5 log reductions. The volume of clam meat (processed in shell) increased with negligible change in mass after exposure to pressure at 552 MPa for 3 min, while the drip loss was reduced. Clams processed at 552 MPa were softer compared to those processed at 276 MPa. However, all HHP processed clams were found to be harder compared to unprocessed. The lightness (L*) of the meat increased although the redness (a*) decreased with increasing pressure. Although high pressure-processed clams may pose a significantly lower risk from V. parahaemolyticus, the effect of the accompanied physical changes on the consumer's decision to purchase HHP clams remains to be determined. Shellfish may contain dangerous foodborne pathogens. Traditional methods of removing those pathogen have been found ineffective against certain pathogens. The objective of this research was to determine the effect of high hydrostatic pressure on V. parahaemolyticus in clams. Processing conditions of 450 MPa for 4 min and 350 MPa for 6 min reduced the initial concentration of V. parahaemolyticus to a nondetectable level, achieving >5 log reductions. © 2013 Institute of Food Technologists®

[Hemodynamic effects of the synthetic analogue of endogenous nitric oxide (II) donors a dinitrosyl iron complex in hypertensive patients with uncomplicated hypertensive crisis].

PubMed

Gosteev, A Iu; Zorin, A V; Rodnenkov, O V; Dragnev, A G; Chazov, E I

2014-01-01

To examine the antihypertensive effect of the synthetic analogue of the endogenous nitric oxide donors in patients with grades 2-3 hypertension and uncomplicated hypertensive crisis (HC). The study included 30 male patients aged 35 to 73 years (mean age 55.5 ± 10.8 years). All the patients had grades 2-3 essential or secondary hypertension. Thirteen (43.3%) patients were observed to have signs of HC; 17 (56.7%) patients had persistent blood pressure (BP) elevation. A dinitrosyl iron complex was injected in a dose of 1.5 or 3 mg per kg of body weight. The purpose of its administration was to lower BP by at least 20% of its baseline level. No significant side effects associated with the administration of the test drug were recorded when the clinical trial protocol was implemented. All the patients reported fever and facial hyperemia during and 10-20 minutes after injection. They all (100%) showed efficient blood pressure reduction of at least 20% of the baseline level. Blood pressure changes were similar when the agent was administered in doses of 1.5 or 3 mg/kg. At 6-8 minutes after the drug was injected, there was a maximal decrease in blood pressure, then its gradual rise and stabilization at a lower level than the baseline one within the following 8 hours. There were no significant differences in the magnitude of a blood pressure reduction after administration of 1.5 and 3 mg/kg. The findings suggest that the dinitrosyl iron complex is highly effective in treating uncomplicated HC. The antihypertensive effect of the drug persists for 8 hours after its injection, which is very important during prehospital therapy. The drug is well tolerated by patients and causes an insignificant number of side effects.

Effect of Multifactorial Treatment Targets and Relative Importance of Hemoglobin A1c, Blood Pressure, and Low-Density Lipoprotein-Cholesterol on Cardiovascular Diseases in Chinese Primary Care Patients With Type 2 Diabetes Mellitus: A Population-Based Retrospective Cohort Study.

PubMed

Wan, Eric Yuk Fai; Fung, Colman Siu Cheung; Yu, Esther Yee Tak; Chin, Weng Yee; Fong, Daniel Yee Tak; Chan, Anca Ka Chun; Lam, Cindy Lo Kuen

2017-08-17

The relative effect of hemoglobin A1c, blood pressure, and low-density lipoprotein-cholesterol (LDL-C) ("ABC" factors) on the prevention of cardiovascular diseases (CVD) among patients with type 2 diabetes mellitus is poorly understood. This study aimed to evaluate the association of key clinical parameters on CVD risk using a multifactorial optimal control approach in Chinese primary care patients with type 2 diabetes mellitus. A population-based retrospective cohort study was conducted on 144 271 Chinese type 2 diabetes mellitus primary care patients, aged 18 to 79 and without prior clinical diagnosis of CVD in 2008-2011. Cox regressions were conducted to examine the association between the combinations of ABC targets (hemoglobin A1c <7%, blood pressure <130/90 mm Hg, and LDL-C <2.6 mmol/L) and risks of CVD (overall), coronary heart disease, stroke, and heart failure. Achieving more ABC targets incrementally reduced the incidence of total CVD and individual disease including coronary heart disease, stroke, and heart failure, irrespective of other patient characteristics. Compared with suboptimal control in all ABC levels, achieving any 1, 2, and all 3 ABC targets reduced the relative risk of CVD by 13% to 42%, 31% to 52%, and 55%, respectively. Among those achieving only 1 ABC target, LDL-C reduction was associated with the greatest CVD risk reduction (42%), followed by blood pressure reduction (18%), and hemoglobin A1c reduction (13%). To achieve the greatest risk reduction for the incidence of CVD, the ultimate goal of treatment should be to achieve target control of hemoglobin A1c, blood pressure, and LDL-C. If it is not possible to achieve all 3 targets, efforts should be prioritized on treating the LDL-C to minimize CVD risk. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Telmisartan is more effective than losartan in reducing proteinuria in patients with diabetic nephropathy.

PubMed

Bakris, George; Burgess, Ellen; Weir, Matthew; Davidai, Giora; Koval, Stephen

2008-08-01

In patients with diabetic nephropathy, lowering blood pressure and reducing proteinuria by over 30% correlates with a slower progression to kidney failure. We compared two different angiotensin receptor-blockers in a double blind, prospective trial of 860 patients with type 2 diabetes whose blood pressure levels was over 130/80 mmHg or who were receiving antihypertensive medication(s) and who had a morning spot urinary protein to creatinine ratio of 700 or more. Patients were randomized to telmisartan (a highly lipophilic agent with a long half-life) or losartan (with low lipophilicity and short half-life). The primary endpoint was the difference in the urinary albumin to creatinine ratio between the groups at 52 weeks. The geometric coefficient of variation and the mean of the urinary albumin to creatinine ratio fell in both groups at 52 weeks but both were significantly greater for the telmisartan compared to the losartan cohort. Mean systolic blood pressure reductions were not significantly different between groups at trial end. We conclude that telmisartan is superior to losartan in reducing proteinuria in hypertensive patients with diabetic nephropathy, despite a similar reduction in blood pressure.

Multiscale modeling and experimental interpretation of perovskite oxide materials in thermochemical energy storage and conversion for application in concentrating solar power

NASA Astrophysics Data System (ADS)

Albrecht, Kevin J.

Decarbonization of the electric grid is fundamentally limited by the intermittency of renewable resources such as wind and solar. Therefore, energy storage will play a significant role in the future of grid-scale energy generation to overcome the intermittency issues. For this reason, concentrating solar power (CSP) plants have been a renewable energy generation technology of interest due to their ability to participate in cost effective and efficient thermal energy storage. However, the ability to dynamically dispatch a CSP plant to meet energy demands is currently limited by the large quantities of sensible thermal energy storage material needed in a molten salt plant. Perovskite oxides have been suggested as a thermochemical energy storage material to enhance the energy storage capabilities of particle-based CSP plants, which combine sensible and chemical modes of energy storage. In this dissertation, computational models are used to establish the thermochemical energy storage potential of select perovskite compositions, identify system configurations that promote high values of energy storage and solar-to-electric efficiency, assess the kinetic and transport limitation of the chemical mode of energy storage, and create receiver and reoxidation reactor models capable of aiding in component design. A methodology for determining perovskite thermochemical energy storage potential is developed based on point defect models to represent perovskite non-stoichiometry as a function of temperature and gas phase oxygen partial pressure. The thermodynamic parameters necessary for the model are extracted from non-stoichiometry measurements by fitting the model using an optimization routine. The procedure is demonstrated for Ca0.9Sr0.1MnO 3-d which displayed combined energy storage values of 705.7 kJ/kg -1 by cycling between 773 K and 0.21 bar oxygen to 1173 K and 10 -4 bar oxygen. Thermodynamic system-level models capable of exploiting perovskite redox chemistry for energy storage in CSP plants are presented. Comparisons of sweep gas and vacuum pumping reduction as well as hot storage conditions indicate that solar-to-electric efficiencies are higher for sweep gas reduction system at equivalent values of energy storage if the energy parasitics of commercially available devices are considered. However, if vacuum pump efficiency between 15% and 30% can be achieved, the reduction methods will be approximately equal. Reducing condition oxygen partial pressures below 10-3 bar for sweep gas reduction and 10-2 bar for vacuum pumping reduction result in large electrical parasitics, which significantly reduce solar-to-electric efficiency. A model based interpretation of experimental measurements made for perovskite redox cycling using sweep gas in a packed bed is presented. The model indicates that long reduction times for equilibrating perovskites with low oxygen partial pressure sweep gas, compared to reoxidation, are primarily due to the oxygen carrying capacity of high purity sweep gas and not surface kinetic limitations. Therefore, achieving rapid reduction in the limited receiver residence time will be controlled by the quantity of sweep gas introduced. Effective kinetic parameters considering surface reaction and radial particle diffusion are fit to the experimental data. Variable order rate expressions without significant particle radial diffusion limitations are shown to be capable of representing the reduction and oxidation data. Modeling of a particle reduction receiver using continuous flow of perovskite solid and sweep gas in counter-flow configuration has identified issues with managing the oxygen evolved by the solid as well as sweep gas flow rates. Introducing sweep gas quantities necessary for equilibrating the solid with oxygen partial pressures below 10-2 are shown to result in gas phase velocities above the entrainment velocity of 500 um particles. Receiver designs with considerations for gas management are investigated and the results indicate that degrees of reduction corresponding to only oxygen partial pressures of 10-2 bar are attained. Numerical investigation into perovskite thermochemical energy storage indicates that achieving high levels of reduction through sweep gas or vacuum pumping to lower gas phase oxygen partial pressure below 10-2 bar display issues with parasitic energy consumption and gas phase management. Therefore, focus on material development should place a premium on thermal reduction and reduction by shifting oxygen partial pressure between ambient and 10-2 bar. Such a material would enable the development of a system with high solar-to-electric efficiencies and degrees of reduction which are attainable in realistic component geometries.

A review of nickel hydrogen battery technology

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Odonnell, Patricia M.

1995-01-01

This paper on nickel hydrogen batteries is an overview of the various nickel hydrogen battery design options, technical accomplishments, validation test results and trends. There is more than one nickel hydrogen battery design, each having its advantage for specific applications. The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar and low pressure metal hydride. State-of-the-art (SOA) nickel hydrogen batteries are replacing nickel cadmium batteries in almost all geosynchronous orbit (GEO) applications requiring power above 1 kW. However, for the more severe low earth orbit (LEO) applications (greater than 30,000 cycles), the current cycle life of 4000 to 10,000 cycles at 60 percent DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low cost satellites. Hence, the challenge is to reduce battery mass, volume and cost. A key is to develop a light weight nickel electrode and alternate battery designs. A common pressure vessel (CPV) nickel hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume and manufacturing costs. A 10 Ah CPV battery has successfully provided power on the relatively short lived Clementine Spacecraft. A bipolar nickel hydrogen battery design has been demonstrated (15,000 LEO cycles, 40 percent DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high pulse power capability. A low pressure aerospace nickel metal hydride battery cell has been developed and is on the market. It is a prismatic design which has the advantage of a significant reduction in volume and a reduction in manufacturing cost.

Nickel hydrogen batteries: An overview

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Odonnell, Patricia M.

1994-01-01

This paper on nickel hydrogen batteries is an overview of the various nickel hydrogen battery design options, technical accomplishments, validation test results and trends. There is more than one nickel hydrogen battery design, each having its advantage for specific applications. The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar and low pressure metal hydride. State-of-the-art (SOA) nickel hydrogen batteries are replacing nickel cadmium batteries in almost all geosynchronous orbit (GEO) applications requiring power above 1 kW. However, for the more severe low earth orbit (LEO) applications (greater than 30,000 cycles), the current cycle life of 4000 to 10,000 cycles at 60 percent DOD should be improved. A LeRC innovative advanced design IPV nickel hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low cost satellites. Hence, the challenge is to reduce battery mass,volume, and cost. A key is to develop a light weight nickel electrode and alternate battery designs. A common pressure vessel (CPV) nickel hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume and manufacturing costs. A 10 Ah CPV battery has successfully provided power on the relatively short lived Clementine Spacecraft. A bipolar nickel hydrogen battery design has been demonstrated (15,000 LEO cycles, 40 percent DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high pulse power capability. A low pressure aerospace nickel metal hydride battery cell has been developed and is on the market. It is a prismatic design which has the advantage of a significant reduction in volume and a reduction in manufacturing cost.

Altered carnitine transport in pressure-overload hypertrophied rat hearts

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Rourke, B.; Foster, K.; Reibel, D.K.

1986-03-01

The authors have previously observed reduced carnitine levels in hypertrophied hearts of rats subjected to aortic constriction. In an attempt to determine the mechanism for reduced myocardial carnitine content, carnitine transport was examined in isolated perfused hearts. Hearts were excised from sham-operated and aortic-constricted rats 3 weeks following surgery and perfused at 60 mm Hg aortic pressure with buffer containing various concentrations of L-/sup 14/C-carnitine. Carnitine uptake by control and hypertrophied hearts was linear throughout 30 minutes of perfusion with 40 ..mu..M carnitine. Total carnitine uptake was significantly reduced by 25% in hypertrophied hearts at each time point examined. Themore » reduction in uptake by hypertrophied hearts was also evident when hearts were perfused with 100 or 200 ..mu..M carnitine. When 0.05 mM mersalyl acid was included in the buffer to inhibit the carrier-mediated component of transport, no difference in carnitine uptake was observed indicating that the transport of carnitine by diffusion was unaltered in the hypertrophied myocardium. Carrier-mediated carnitine uptake (total uptake - uptake by diffusion) was significantly reduced by approximately 40% in hypertrophied hearts at all concentrations examined. Thus, the reduction in carnitine content in the pressure-overload hypertrophied rat heart appears to be due to a reduction in carrier-mediated carnitine uptake by the heart.« less

Evolution of high-level resistance during low-level antibiotic exposure.

PubMed

Wistrand-Yuen, Erik; Knopp, Michael; Hjort, Karin; Koskiniemi, Sanna; Berg, Otto G; Andersson, Dan I

2018-04-23

It has become increasingly clear that low levels of antibiotics present in many environments can select for resistant bacteria, yet the evolutionary pathways for resistance development during exposure to low amounts of antibiotics remain poorly defined. Here we show that Salmonella enterica exposed to sub-MIC levels of streptomycin evolved high-level resistance via novel mechanisms that are different from those observed during lethal selections. During lethal selection only rpsL mutations are found, whereas at sub-MIC selection resistance is generated by several small-effect resistance mutations that combined confer high-level resistance via three different mechanisms: (i) alteration of the ribosomal RNA target (gidB mutations), (ii) reduction in aminoglycoside uptake (cyoB, nuoG, and trkH mutations), and (iii) induction of the aminoglycoside-modifying enzyme AadA (znuA mutations). These results demonstrate how the strength of the selective pressure influences evolutionary trajectories and that even weak selective pressures can cause evolution of high-level resistance.

Simulating the Impact of Improved Cardiovascular Risk Interventions on Clinical and Economic Outcomes in Russia

PubMed Central

Shum, Kenny; Alperin, Peter; Shalnova, Svetlana; Boytsov, Sergey; Kontsevaya, Anna; Vigdorchik, Alexey; Guetz, Adam; Eriksson, Jennifer; Hughes, David

2014-01-01

Objectives Russia faces a high burden of cardiovascular disease. Prevalence of all cardiovascular risk factors, especially hypertension, is high. Elevated blood pressure is generally poorly controlled and medication usage is suboptimal. With a disease-model simulation, we forecast how various treatment programs aimed at increasing blood pressure control would affect cardiovascular outcomes. In addition, we investigated what additional benefit adding lipid control and smoking cessation to blood pressure control would generate in terms of reduced cardiovascular events. Finally, we estimated the direct health care costs saved by treating fewer cardiovascular events. Methods The Archimedes Model, a detailed computer model of human physiology, disease progression, and health care delivery was adapted to the Russian setting. Intervention scenarios of achieving systolic blood pressure control rates (defined as systolic blood pressure <140 mmHg) of 40% and 60% were simulated by modifying adherence rates of an antihypertensive medication combination and compared with current care (23.9% blood pressure control rate). Outcomes of major adverse cardiovascular events; cerebrovascular event (stroke), myocardial infarction, and cardiovascular death over a 10-year time horizon were reported. Direct health care costs of strokes and myocardial infarctions were derived from official Russian statistics and tariff lists. Results To achieve systolic blood pressure control rates of 40% and 60%, adherence rates to the antihypertensive treatment program were 29.4% and 65.9%. Cardiovascular death relative risk reductions were 13.2%, and 29.6%, respectively. For the current estimated 43,855,000-person Russian hypertensive population, each control-rate scenario resulted in an absolute reduction of 1.0 million and 2.4 million cardiovascular deaths, and a reduction of 1.2 million and 2.7 million stroke/myocardial infarction diagnoses, respectively. Averted direct costs from current care levels ($7.6 billion [in United States dollars]) were $1.1 billion and $2.6 billion, respectively. PMID:25141122

To Legislate or Not to Legislate? A Comparison of the UK and South African Approaches to the Development and Implementation of Salt Reduction Programs

PubMed Central

Charlton, Karen; Webster, Jacqui; Kowal, Paul

2014-01-01

The World Health Organization promotes salt reduction as a best-buy strategy to reduce chronic diseases, and Member States have agreed to a 30% reduction target in mean population salt intake by 2025. Whilst the UK has made the most progress on salt reduction, South Africa was the first country to pass legislation for salt levels in a range of processed foods. This paper compares the process of developing salt reduction strategies in both countries and highlights lessons for other countries. Like the UK, the benefits of salt reduction were being debated in South Africa long before it became a policy priority. Whilst salt reduction was gaining a higher profile internationally, undoubtedly, local research to produce context-specific, domestic costs and outcome indicators for South Africa was crucial in influencing the decision to legislate. In the UK, strong government leadership and extensive advocacy activities initiated in the early 2000s have helped drive the voluntary uptake of salt targets by the food industry. It is too early to say which strategy will be most effective regarding reductions in population-level blood pressure. Robust monitoring and transparent mechanisms for holding the industry accountable will be key to continued progress in each of the countries. PMID:25230210

Development of a three-man preprototype CO2 collection subsystem for spacecraft application

NASA Technical Reports Server (NTRS)

Schubert, F. H.; Wynveen, R. A.; Quattrone, P. D.; Marshall, R. D.

1977-01-01

Future long-duration manned space missions will require regenerable carbon dioxide (CO2) collection concepts such as the Electrochemical Depolarized CO2 Concentrator (EDC). A three-man-capacity preprototype CO2 Collection Subsystem (CS-3) is being developed for eventual flight demonstration as part of the Air Revitalization System (ARS) of the Regenerative Life Support Evaluation (RLSE) experiment. The CS-3 employs an EDC to concentrate CO2 from the low partial-pressure levels required of spacecraft atmospheres to high partial-pressure levels needed for oxygen (O2) recovery through CO2 reduction processes. The CS-3 is sized to remove a nominal 3.0 kg/day (6.6 lb/day) of the CO2 to maintain the CO2 partial pressure (pCO2) of the cabin atmosphere at 400 Pa (3 mm Hg) or less. This paper presents the preprototype design, configuration, operation, and projected performance characteristics.

Low-speed wind tunnel tests of a 50.8-centimeter (20-in.) 1.15-pressure-ratio fan engine model

NASA Technical Reports Server (NTRS)

Wesoky, H. L.; Abbott, J. M.; Albers, J. A.; Dietrich, D. A.

1974-01-01

At a typical STOL aircraft takeoff and landing velocity, wind tunnel aerodynamic and acoustic measurements demonstrated that an inlet lip-area contraction ratio of 1.35 was superior to a ratio of 1.26 at high incidence angles. A 17 percent reduction in net thrust and an increase of 9 decibels in sound pressure level at the blade passing frequency resulted from inlet flow separation at an incidence angle of 50 deg with the 1.26-contraction-ratio inlet. Reverse-thrust forces obtained with blade rotation through the feathered angle were 1.8 times larger than with blade rotation through the flat angle. Reverse-thrust force was reduced from 30 to 50 percent and sound pressure level increased from 3 to 7 decibels at the blade passing frequency between the wind-tunnel-off condition and a typical STOL aircraft landing velocity.

Focus on prevention, diagnosis and treatment of hypertension in children and adolescents

PubMed Central

2013-01-01

The European Society of Hypertension has recently published its recommendations on prevention, diagnosis and treatment of high blood pressure in children and adolescents. Taking this contribution as a starting point the Study Group of Hypertension of the Italian Society of Pediatrics together with the Italian Society of Hypertension has conducted a reappraisal of the most recent literature on this subject. The present review does not claim to be an exhaustive description of hypertension in the pediatric population but intends to provide Pediatricians with practical and updated indications in order to guide them in this often unappreciated problem. This document pays particular attention to the primary hypertension which represents a growing problem in children and adolescents. Subjects at elevated risk of hypertension are those overweight, with low birth weight and presenting a family history of hypertension. However, also children who do not present these risk factors may have elevated blood pressure levels. In pediatric age diagnosis of hypertension or high normal blood pressure is made with repeated office blood pressure measurements that show values exceeding the reference values. Blood pressure should be monitored at least once a year with adequate methods and instrumentation and the observed values have to be interpreted according to the most updated nomograms that are adjusted for children’s gender, age and height. Currently other available methods such as ambulatory blood pressure monitoring and home blood pressure measurement are not yet adequately validated for use as diagnostic instruments. To diagnose primary hypertension it is necessary to exclude secondary forms. The probability of facing a secondary form of hypertension is inversely proportional to the child’s age and directly proportional to blood pressure levels. Medical history, clinical data and blood tests may guide the differential diagnosis of primary versus secondary forms. The prevention of high blood pressure is based on correct lifestyle and nutrition, starting from childhood age. The treatment of primary hypertension in children is almost exclusively dietary/behavioral and includes: a) reduction of overweight whenever present b) reduction of dietary sodium intake c) increase in physical activity. Pharmacological therapy will be needed rarely and only in specific cases. PMID:23510329

Enhanced viscous flow drag reduction using acoustic excitation

NASA Technical Reports Server (NTRS)

Nagel, R. T.

1988-01-01

Large eddy break up devices (LEBUs) constitute a promising method of obtaining drag reduction in a turbulent boundary layer. Enhancement of the LEBU effectiveness by exciting its trailing edge with acoustic waves phase locked to the large scale structure influencing the momentum transfer to the wall is sought. An initial estimate of the required sound pressure level for an effective pulse was obtained by considering the magnitude of the pressure perturbations at the near wake of a thin plate in inviscid flow. Detailed skin friction measurments were obtained in the flow region downstream of a LEBU excited with acoustic waves. The data are compared with skin friction measurements of a simply manipulated flow, without acoustic excitation and with a plain flow configuration. The properties and the scales of motion in the flow regime downstream of the acoustically excited LEBU are studied. A parametric study based upon the characteristics of the acoustic input was pursued in addition to the careful mapping of the drag reduction phenomenon within the acoustically manipulated boundary layer. This study of boundary layer manipulation has lead to improved skin friction drag reduction and further understanding of the turbulent boundary layer.

Blood pressure management and guideline adherence in hypertensive emergencies and urgencies: A comparison between telemedically supported and conventional out-of-hospital care.

PubMed

Brokmann, Jörg C; Rossaint, Rolf; Müller, Michael; Fitzner, Christina; Villa, Luigi; Beckers, Stefan K; Bergrath, Sebastian

2017-07-01

Prehospital hypertensive emergencies and urgencies are common, but evidence is lacking. Telemedically supported hypertensive emergencies and urgencies were prospectively collected (April 2014-March 2015) and compared retrospectively with a historical control group of on-scene physician care in the emergency medical service of Aachen, Germany. Blood pressure management and guideline adherence were evaluated. Telemedical (n=159) vs conventional (n=172) cases: blood pressure reductions of 35±24 mm Hg vs 44±23 mm Hg revealed a group effect adjusted for baseline differences (P=.0006). Blood pressure management in categories: no reduction 6 vs 0 (P=.0121); reduction ≤25% (recommended range) 113 vs 110 patients (P=.2356); reduction >25% to 30% 13 vs 29 (0.020); reduction >30% 12 vs 16 patients (P=.5608). The telemedical approach led to less pronounced blood pressure reductions and a tendency to improved guideline adherence. Telemedically guided antihypertensive care may be an alternative to conventional care especially for potentially underserved areas. ©2017 Wiley Periodicals, Inc.

Impact of changes in blood pressure during the treatment of acute decompensated heart failure on renal and clinical outcomes†

PubMed Central

Testani, Jeffrey M.; Coca, Steven G.; McCauley, Brian D.; Shannon, Richard P.; Kimmel, Stephen E.

2011-01-01

Aims One of the primary determinants of blood flow in regional vascular beds is perfusion pressure. Our aim was to investigate if reduction in blood pressure during the treatment of decompensated heart failure would be associated with worsening renal function (WRF). Our secondary aim was to evaluate the prognostic significance of this potentially treatment-induced form of WRF. Methods and results Subjects included in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial limited data were studied (386 patients). Reduction in systolic blood pressure (SBP) was greater in patients experiencing WRF (−10.3 ± 18.5 vs. −2.8 ± 16.0 mmHg, P < 0.001) with larger reductions associated with greater odds for WRF (odds ratio = 1.3 per 10 mmHg reduction, P < 0.001). Systolic blood pressure reduction (relative change > median) was associated with greater doses of in-hospital oral vasodilators (P ≤ 0.017), thiazide diuretic use (P = 0.035), and greater weight reduction (P = 0.023). In patients with SBP-reduction, WRF was not associated with worsened survival [adjusted hazard ratio (HR) = 0.76, P = 0.58]. However, in patients without SBP-reduction, WRF was strongly associated with increased mortality (adjusted HR = 5.3, P < 0.001, P interaction = 0.001). Conclusion During the treatment of decompensated heart failure, significant blood pressure reduction is strongly associated with WRF. However, WRF that occurs in the setting of SBP-reduction is not associated with an adverse prognosis, whereas WRF in the absence of this provocation is strongly associated with increased mortality. These data suggest that WRF may represent the final common pathway of several mechanistically distinct processes, each with potentially different prognostic implications. PMID:21693504

Impact of changes in blood pressure during the treatment of acute decompensated heart failure on renal and clinical outcomes.

PubMed

Testani, Jeffrey M; Coca, Steven G; McCauley, Brian D; Shannon, Richard P; Kimmel, Stephen E

2011-08-01

One of the primary determinants of blood flow in regional vascular beds is perfusion pressure. Our aim was to investigate if reduction in blood pressure during the treatment of decompensated heart failure would be associated with worsening renal function (WRF). Our secondary aim was to evaluate the prognostic significance of this potentially treatment-induced form of WRF. Subjects included in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial limited data were studied (386 patients). Reduction in systolic blood pressure (SBP) was greater in patients experiencing WRF (-10.3 ± 18.5 vs. -2.8 ± 16.0 mmHg, P < 0.001) with larger reductions associated with greater odds for WRF (odds ratio = 1.3 per 10 mmHg reduction, P < 0.001). Systolic blood pressure reduction (relative change > median) was associated with greater doses of in-hospital oral vasodilators (P ≤ 0.017), thiazide diuretic use (P = 0.035), and greater weight reduction (P = 0.023). In patients with SBP-reduction, WRF was not associated with worsened survival [adjusted hazard ratio (HR) = 0.76, P = 0.58]. However, in patients without SBP-reduction, WRF was strongly associated with increased mortality (adjusted HR = 5.3, P < 0.001, P interaction = 0.001). During the treatment of decompensated heart failure, significant blood pressure reduction is strongly associated with WRF. However, WRF that occurs in the setting of SBP-reduction is not associated with an adverse prognosis, whereas WRF in the absence of this provocation is strongly associated with increased mortality. These data suggest that WRF may represent the final common pathway of several mechanistically distinct processes, each with potentially different prognostic implications.

Blood pressure and stroke: an overview of published reviews.

PubMed

Lawes, Carlene M M; Bennett, Derrick A; Feigin, Valery L; Rodgers, Anthony

2004-03-01

The last few years have seen a considerable increase in the amount of information available concerning blood pressure (BP) and stroke associations. This article provides an overview of published reviews of the effects on stroke seen in trials of BP-lowering drugs and compares these with the results available from cohort studies. We present a review of major overviews of prospective cohort studies and an updated meta-analysis of >40 randomized controlled trials of BP lowering, which included >188 000 participants and approximately 6800 stroke events. Cohort studies now indicate that in the Asia Pacific region as well as in North America and Western Europe, each 10 mm Hg lower systolic BP is associated with a decrease in risk of approximately one third in subjects aged 60 to 79 years. The association is continuous down to levels of at least 115/75 mm Hg and is consistent across sexes, regions, and stroke subtypes and for fatal and nonfatal events. The proportional association is age dependent but is still a strong and positive association in those aged 80 years. Data from randomized controlled trials, in which mean age at event was approximately 70 years, indicate that a 10 mm Hg reduction in systolic BP is associated with a reduction in risk of stroke of approximately one third. Per mm Hg systolic BP reduction, the benefits for stroke appear similar between agents, by baseline BP levels, and whether or not individuals have a past history of cardiovascular disease. There is, however, evidence of greater benefit with a larger BP reduction. The epidemiologically expected benefits of BP lowering for stroke risk reduction are broadly consistent across a range of different population subgroups. There are greater benefits from larger BP reductions, and initiating and maintaining BP reduction for stroke prevention is a more important issue than choice of initial agent.

Blood pressure and stroke: an overview of published reviews.

PubMed

Lawes, Carlene M M; Bennett, Derrick A; Feigin, Valery L; Rodgers, Anthony

2004-04-01

The last few years have seen a considerable increase in the amount of information available concerning blood pressure (BP) and stroke associations. This article provides an overview of published reviews of the effects on stroke seen in trials of BP-lowering drugs and compares these with the results available from cohort studies. We present a review of major overviews of prospective cohort studies and an updated meta-analysis of >40 randomized controlled trials of BP lowering, which included >188 000 participants and approximately 6800 stroke events. Cohort studies now indicate that in the Asia Pacific region as well as in North America and Western Europe, each 10 mm Hg lower systolic BP is associated with a decrease in risk of stroke of approximately one third in subjects aged 60 to 79 years. The association is continuous down to levels of at least 115/75 mm Hg and is consistent across sexes, regions, and stroke subtypes and for fatal and nonfatal events. The proportional association is age dependent but is still strong and positive in those aged 80 years. Data from randomized controlled trials, in which mean age at event was approximately 70 years, indicate that a 10 mm Hg reduction in systolic BP is associated with a reduction in risk of stroke of approximately one third. Per mm Hg systolic BP reduction, the relative benefits for stroke appear similar between agents, by baseline BP levels, and whether or not individuals have a past history of cardiovascular disease. There is, however, evidence of greater benefit with a larger BP reduction. The epidemiologically expected benefits of BP lowering for stroke risk reduction are broadly consistent across a range of different population subgroups. There are greater benefits from larger BP reductions, and initiating and maintaining BP reduction for stroke prevention is a more important issue than choice of initial agent.

A Gnotobiotic Pig Model for Determining Human Norovirus Inactivation by High-Pressure Processing

PubMed Central

Lou, Fangfei; Ye, Mu; Ma, Yuanmei; Li, Xinhui; DiCaprio, Erin; Chen, Haiqiang; Krakowka, Steven; Hughes, John; Kingsley, David

2015-01-01

Human norovirus (NoV) is responsible for over 90% of outbreaks of acute nonbacterial gastroenteritis worldwide and accounts for 60% of cases of foodborne illness in the United States. Currently, the infectivity of human NoVs is poorly understood due to the lack of a cell culture system. In this study, we determined the survival of a human NoV genogroup II, genotype 4 (GII.4) strain in seeded oyster homogenates after high-pressure processing (HPP) using a novel receptor binding assay and a gnotobiotic pig model. Pressure conditions of 350 MPa at 0°C for 2 min led to a 3.7-log10 reduction in the number of viral RNA copies in oysters, as measured by the porcine gastric mucin-conjugated magnetic bead (PGM-MB) binding assay and real-time RT-PCR, whereas pressure conditions of 350 MPa at 35°C for 2 min achieved only a 1-log10 reduction in the number of RNA copies. Newborn gnotobiotic piglets orally fed oyster homogenate treated at 350 MPa and 0°C for 2 min did not have viral RNA shedding in feces, histologic lesions, or viral replication in the small intestine. In contrast, gnotobiotic piglets fed oysters treated at 350 MPa and 35°C for 2 min had high levels of viral shedding in feces and exhibited significant histologic lesions and viral replication in the small intestine. Collectively, these data demonstrate that (i) human NoV survival estimated by an in vitro PGM-MB virus binding assay is consistent with the infectivity determined by an in vivo gnotobiotic piglet model and (ii) HPP is capable of inactivating a human NoV GII.4 strain at commercially acceptable pressure levels. PMID:26187968

Upper cretaceous microbial petroleum systems in north-central Montana

USGS Publications Warehouse

Lillis, Paul G.

2007-01-01

Methanogenesis began soon after the deposition (early-stage methanogenesis) of the Cenomanian to Campanian source sediments, and was either sustained or rejuvenated by episodic meteoric water influx until sometime in the Paleogene. Methanogenesis probably continued until CO2 and hydrogen were depleted or the pore size was compacted to below tolerance levels of the methanogens. The composition of the Montana and Colorado Group gases and coproduced formation water precludes a scenario of late-stage methanogenesis like the Antrim gas system in the Michigan basin. Some portion of the methane charge was originally dissolved in the pore waters, and subsequent reduction in hydrostatic pressure caused the methane to exsolve and migrate into local stratigraphic and structural traps. The critical moment of the microbial gas systems is this timing of exsolution rather than the time of generation (methanogenesis). Other studies suggest that the reduction in hydrostatic pressure may have been caused by multiple geologic events including the lowering of sea level in the Late Cretaceous, and subsequent uplift and erosion events, the youngest of which began about 5 Ma.

Flow noise of an underwater vector sensor embedded in a flexible towed array.

PubMed

Korenbaum, Vladimir I; Tagiltsev, Alexander A

2012-05-01

The objective of this work is to simulate the flow noise of a vector sensor embedded in a flexible towed array. The mathematical model developed, based on long-wavelength analysis of the inner space of a cylindrical multipole source, predicts the reduction of the flow noise of a vector sensor embedded in an underwater flexible towed array by means of intensimetric processing (cross-spectral density calculation of oscillatory velocity and sound-pressure-sensor responses). It is found experimentally that intensimetric processing results in flow noise reduction by 12-25 dB at mean levels and by 10-30 dB in fluctuations compared to a squared oscillatory velocity channel. The effect of flow noise suppression in the intensimetry channel relative to a squared sound pressure channel is observed, but only for frequencies above the threshold. These suppression values are 10-15 dB at mean noise levels and 3-6 dB in fluctuations. At towing velocities of 1.5-3 ms(-1) and an accumulation time of 98.3 s, the threshold frequency in fluctuations is between 30 and 45 Hz.

[Analysis of the Effectiveness of Renoprotection of Low-Protein Diet and Ketoanalogues of Amino Acids In Patients With Chronic Kidney Disease].

PubMed

Sigitova, O N; Arkhipov, E V; Kim, T Y

2015-01-01

Analysis of the effectiveness of renoprotection in patients with chronic kidney disease (CKD), who is observed by general practitioners for up to 72.1 months, keeping traditional LPD or LPD with prescription of ketoanalogues of amino acids (KA/AK). 63 patients with CKD stages 3-4, mainly with glomerulonephritis (GN), were divided into 3 groups: 1 gr--31 patients (53.3 ± 3.1 years old; M/F--18/13), LPD with prescription of ketoanalogues of amino acids; 2 gr--22 patients (54.9 3.2 years old; M/F--13/9) traditional LPD without ketoanalogues; 3 gr--10 patients (51.7 ± 4.2 years old; M/F--6/4) with natural course of CKD. Group 4 (control)--30 healthy subjects (52.3 ± 2.2 years old; M/F--16/14). The following parameters were studied: dynamics of the glomerular filtration rate (GFR), systolic blood pressure (SBP), diastolic blood pressure (DBP), hemoglobin levels (Hb), daily proteinuria, and basic parameters of protein, lipid and phosphate- calcium metabolism. The rate of decline in GFR was significantly lower in patients of the first group (-0.78 mL/min/year) than those of the second group (-4.9 ml/min/year). 9.7% of patients of the first group needed the start of renal replacement therapy at the end of the observation, 18.1%--of the second group and 40%--of the third. All patients who received renoprotective therapy, including low-protein diet with KA/AA reached target levels of blood pressure < 140/90 mm Hg. Patients of this group was able to achieve a significant reduction in proteinuria, improvement of lipid metabolism, prevent of reduction of Hb and the development of metabolic disorders of protein and calcium-phosphate metabolism. The second group of patients, following nephroprotection recommendations and LPD without KA/AA, had fewer reductions in BP without reaching the target level, DBP did not change; reduction of proteinuria was less significant than in group 1. There was no negative dynamics of protein and calcium-phosphate metabolism, though significantly increased levels of total cholesterol and LHD were observed. The third group of patients, who did not follow the renoprotection recommendations demonstrated negative dynamics of the studied parameters. Renoprotection based on the use KA/AA in patients with CKD stages 3-4 proved to be more effective than without it in slowing the rate of decline in GFR, hypertension correction, proteinuria reduction, maintaining the level of Hb, prevention of disorders of protein and calcium-phosphate metabolism, as well as correction of the lipid metabolism.

Non-invasive Positive Pressure Ventilation during Sleep at 3800m: relationship to Acute Mountain Sickness and sleeping oxyhemoglobin saturation

PubMed Central

Johnson, PL; Popa, DA; Prisk, GK; Sullivan, CE; Edwards, N

2014-01-01

Background and objectives Ascent to high altitude results in hypobaric hypoxia and some individuals will develop Acute Mountain Sickness, which has been shown to be associated with low oxyhemoglobin saturation during sleep. Previous research has shown that positive end-expiratory pressure by use of expiratory valves in a face mask while awake, results in a reduction in AMS symptoms and higher oxyhemoglobin saturation. We aimed to test whether pressure ventilation during sleep would prevent AMS by keeping oxyhaemoglobin higher during sleep. Methods We compared sleeping oxyhemoglobin saturation and the incidence and severity of Acute Mountain Sickness in seven subjects sleeping for two consecutive nights at 3800m above sea level using either non-invasive positive pressure ventilation that delivered positive inspiratory and expiratory airway pressure via a face mask, or sleeping without assisted ventilation. The presence and severity of Acute Mountain Sickness was assessed by administration of the Lake Louise questionnaire. Results We found significant increases in the mean and minimum sleeping oxyhemoglobin saturation and decreases in AMS symptoms in subjects who used positive pressure ventilation during sleep. Mean and minimum sleeping SaO2 was lower in subjects who developed AMS after the night spent without positive pressure ventilation. Conclusion The use of positive pressure ventilation during sleep at 3800m significantly increased the sleeping oxygen saturation; we suggest that the marked reduction in symptoms of AMS is due to this higher sleeping SaO2. We agree with the findings from previous studies that the development of AMS is associated with a lower sleeping oxygen saturation. PMID:20051046

Bench experiments comparing simulated inspiratory effort when breathing helium-oxygen mixtures to that during positive pressure support with air

PubMed Central

2012-01-01

Background Inhalation of helium-oxygen (He/O2) mixtures has been explored as a means to lower the work of breathing of patients with obstructive lung disease. Non-invasive ventilation (NIV) with positive pressure support is also used for this purpose. The bench experiments presented herein were conducted in order to compare simulated patient inspiratory effort breathing He/O2 with that breathing medical air, with or without pressure support, across a range of adult, obstructive disease patterns. Methods Patient breathing was simulated using a dual-chamber mechanical test lung, with the breathing compartment connected to an ICU ventilator operated in NIV mode with medical air or He/O2 (78/22 or 65/35%). Parabolic or linear resistances were inserted at the inlet to the breathing chamber. Breathing chamber compliance was also varied. The inspiratory effort was assessed for the different gas mixtures, for three breathing patterns, with zero pressure support (simulating unassisted spontaneous breathing), and with varying levels of pressure support. Results Inspiratory effort increased with increasing resistance and decreasing compliance. At a fixed resistance and compliance, inspiratory effort increased with increasing minute ventilation, and decreased with increasing pressure support. For parabolic resistors, inspiratory effort was lower for He/O2 mixtures than for air, whereas little difference was measured for nominally linear resistance. Relatively small differences in inspiratory effort were measured between the two He/O2 mixtures. Used in combination, reductions in inspiratory effort provided by He/O2 and pressure support were additive. Conclusions The reduction in inspiratory effort afforded by breathing He/O2 is strongly dependent on the severity and type of airway obstruction. Varying helium concentration between 78% and 65% has small impact on inspiratory effort, while combining He/O2 with pressure support provides an additive reduction in inspiratory effort. In addition, breathing He/O2 alone may provide an alternative to pressure support in circumstances where NIV is not available or poorly tolerated. PMID:23031537

Urocortin-2 infusion in acute decompensated heart failure: findings from the UNICORN study (urocortin-2 in the treatment of acute heart failure as an adjunct over conventional therapy).

PubMed

Chan, W Y Wandy; Frampton, Christopher M; Crozier, Ian G; Troughton, Richard W; Richards, A Mark

2013-10-01

The purpose of this study is to investigate the effects of urocortin-2 as adjunct therapy in acute decompensated heart failure (ADHF). Urocortin-2 produced favorable integrated effects in experimental heart failure but there are no equivalent human data. We describe the first therapeutic study of urocortin-2 infusion in ADHF. Fifty-three patients with ADHF were randomly assigned to 5 ng/kg/min of urocortin-2 or placebo infusion for 4 h as an adjunct therapy. Changes in vital signs, plasma neurohormonal and renal indices during treatment were compared using repeated-measures analysis of covariance. Ten patients in each arm underwent more detailed invasive hemodynamic evaluation. Urocortin-2 produced greater falls in systolic blood pressure compared to placebo (16 ± 5.8 mm Hg, p < 0.001) with nonsignificant increases in heart rate (5.7 ± 3.8 beats/min, p = 0.07) and increased cardiac output (2.1 ± 0.4 l/min vs. -0.1 ± 0.4 l/min, p < 0.001) associated with a 47% reduction in calculated total peripheral resistance (p = 0.015). Falls in pulmonary artery and pulmonary capillary wedge pressures did not differ significantly between groups. Urocortin-2 reduced urine volume and creatinine clearance during infusion but these returned to above baseline level in the 8 h after infusion. Plasma renin activity rose briefly with urocortin-2 coinciding with reductions in blood pressure (p < 0.001). B-type natriuretic peptide levels fell significantly over 24 h with urocortin-2 (p < 0.01) but not with placebo. Urocortin-2 infusion in ADHF markedly augmented cardiac output without significant reflex tachycardia. Renal indices fell transiently concurrent with urocortin-2-induced reductions in blood pressure. Further investigations are required to uncover the full potential of urocortin-2 in treating ADHF. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Daily potassium intake and sodium-to-potassium ratio in the reduction of blood pressure: a meta-analysis of randomized controlled trials.

PubMed

Binia, Aristea; Jaeger, Jonathan; Hu, Youyou; Singh, Anurag; Zimmermann, Diane

2015-08-01

To evaluate the efficacy of daily potassium intake on decreasing blood pressure in non-medicated normotensive or hypertensive patients, and to determine the relationship between potassium intake, sodium-to-potassium ratio and reduction in blood pressure. Mixed-effect meta-analyses and meta-regression models. Medline and the references of previous meta-analyses. Randomized controlled trials with potassium supplementation, with blood pressure as the primary outcome, in non-medicated patients. Fifteen randomized controlled trials of potassium supplementation in patients without antihypertensive medication were selected for the meta-analyses (917 patients). Potassium supplementation resulted in reduction of SBP by 4.7 mmHg [95% confidence interval (CI) 2.4-7.0] and DBP by 3.5 mmHg (95% CI 1.3-5.7) in all patients. The effect was found to be greater in hypertensive patients, with a reduction of SBP by 6.8 mmHg (95% CI 4.3-9.3) and DBP by 4.6 mmHg (95% CI 1.8-7.5). Meta-regression analysis showed that both increased daily potassium excretion and decreased sodium-to-potassium ratio were associated with blood pressure reduction (P < 0.05). Increased total daily potassium urinary excretion from 60 to 100 mmol/day and decrease of sodium-to-potassium ratio were shown to be necessary to explain the estimated effect. Potassium supplementation is associated with reduction of blood pressure in patients who are not on antihypertensive medication, and the effect is significant in hypertensive patients. The reduction in blood pressure significantly correlates with decreased daily urinary sodium-to-potassium ratio and increased urinary potassium. Patients with elevated blood pressure may benefit from increased potassium intake along with controlled or decreased sodium intake.

NOS3 genotype-dependent correlation between blood pressure and physical activity.

PubMed

Kimura, Tomomi; Yokoyama, Tetsuji; Matsumura, Yasuhiro; Yoshiike, Nobuo; Date, Chigusa; Muramatsu, Masaaki; Tanaka, Heizo

2003-02-01

Endothelium-dependent vasorelaxation plays an important role in reduction of blood pressure and is mediated through release of nitric oxide (NO), which is generated by constitutively expressed endothelial nitric oxide synthase (NOS3). Exercise also augments NO release and has been recommended for primary prevention and improvement of hypertension, but individual responses are highly variable. We therefore postulated that genetic polymorphisms of NOS3 might interact with physical activity level to differentially influence blood pressure level. We genotyped 832 healthy Japanese (mean age of 54.4+/-8.6 years, 372 men and 460 women) for a polymorphism of NOS3 in intron 4 (ecNOS4a/b), using the polymerase chain reaction method, and scored their habitual physical activity level by using the rate of energy expenditure per resting metabolic rate through an interview according to a semiquantitative assessment method. Only in the subjects who had the rarer a allele (aa+ba type), systolic blood pressure was found to be inversely correlated with physical activity level (P for linear trend=0.0496, for interaction=0.0071). Eventually, this polymorphism was significantly associated with the prevalence of systolic hypertension only in the subjects who were in the lowest tertile of physical activity level (OR=2.4, 95% CI, 1.1 to 5.6, P for interaction=0.0474). In the present study, we found a significant interaction between the genotype and physical activity level on systolic blood pressure. These results might allow a better understanding of the mechanism to improve hypertension by exercise and to thereby reduce the risk of cardiovascular disease.

The decrease in yield strength in NiAl due to hydrostatic pressure

NASA Technical Reports Server (NTRS)

Margevicius, R. W.; Lewandowski, J. J.; Locci, I.

1992-01-01

The decrease in yield strength in NiAl due to hydrostatic pressure is examined via a comparison of the tensile flow behavior in the low strain regime at 0.1 MPa for NiAl which was cast, extruded, and annealed for 2 hr at 827 C in argon and very slowly cooled to room temperature. Pressurization to 1.4 GPa produces a subsequent reduction at 0.1 MP in proportional limit by 40 percent as well as a 25-percent reduction in the 0.2-percent offset yield strength, while pressurization with lower pressures produces a similar reduction, although smaller in magnitude.

Inactivation of Staphylococcus aureus and Salmonella enteritidis in tryptic soy broth and caviar samples by high pressure processing.

PubMed

Fioretto, F; Cruz, C; Largeteau, A; Sarli, T A; Demazeau, G; El Moueffak, A

2005-08-01

We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 10(8)-10(9) colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar.

Reduction of ventricular size after shunting for normal pressure hydrocephalus related to CSF dynamics before shunting.

PubMed Central

Tans, J T; Poortvliet, D C

1988-01-01

Reduction of ventricular size was determined by repeated computed tomography in 30 adult patients shunted for normal pressure hydrocephalus (NPH) and related to the pressure-volume index (PVI) and resistance to outflow of cerebrospinal fluid (Rcsf) measured before shunting. Rapid and marked reduction of ventricular size (n = 10) was associated with a significantly lower PVI than slow and moderate to marked (n = 13) or minimal to mild reduction (n = 7). Otherwise no relationship could be found between the reduction of ventricular size and PVI or Rcsf. It is concluded that both rate and magnitude of reduction of ventricular size after shunting for NPH are extremely variable. High brain elasticity seems to be the best predictor of rapid and marked reduction. PMID:3379425

Non-invasive positive pressure ventilation during sleep at 3800 m: Relationship to acute mountain sickness and sleeping oxyhaemoglobin saturation.

PubMed

Johnson, Pamela L; Popa, Daniel A; Prisk, G Kim; Edwards, Natalie; Sullivan, Colin E

2010-02-01

Overnight oxyhaemoglobin desaturation is related to AMS. AMS can be debilitating and may require descent. Positive pressure ventilation during sleep at high altitude may prevent AMS and therefore be useful in people travelling to high altitude, who are known to suffer from AMS. Ascent to high altitude results in hypobaric hypoxia and some individuals will develop acute mountain sickness (AMS), which has been shown to be associated with low oxyhaemoglobin saturation during sleep. Previous research has shown that positive end-expiratory pressure by use of expiratory valves in a face mask while awake results in a reduction in AMS symptoms and higher oxyhaemoglobin saturation. We aimed to determine whether positive pressure ventilation would prevent AMS by increasing oxygenation during sleep. We compared sleeping oxyhaemoglobin saturation and the incidence and severity of AMS in seven subjects sleeping for two consecutive nights at 3800 m above sea level using either non-invasive positive pressure ventilation that delivered positive inspiratory and expiratory airway pressure via a face mask, or sleeping without assisted ventilation. The presence and severity of AMS were assessed by administration of the Lake Louise questionnaire. We found significant increases in the mean and minimum sleeping oxyhaemoglobin saturation and decreases in AMS symptoms in subjects who used positive pressure ventilation during sleep. Mean and minimum sleeping SaO2 was lower in subjects who developed AMS after the night spent without positive pressure ventilation. The use of positive pressure ventilation during sleep at 3800 m significantly increased the sleeping oxygen saturation; we suggest that the marked reduction in symptoms of AMS is due to this higher sleeping SaO2. We agree with the findings from previous studies that the development of AMS is associated with a lower sleeping oxygen saturation.

Experimental investigation of shock-cell noise reduction for dual-stream nozzles in simulated flight comprehensive data report. Volume 1: Test nozzles and acoustic data

NASA Technical Reports Server (NTRS)

Yamamoto, K.; Janardan, B. A.; Brausch, J. F.; Hoerst, D. J.; Price, A. O.

1984-01-01

Parameters which contribute to supersonic jet shock noise were investigated for the purpose of determining means to reduce such noise generation to acceptable levels. Six dual-stream test nozzles with varying flow passage and plug closure designs were evaluated under simulated flight conditions in an anechoic chamber. All nozzles had combined convergent-divergent or convergent flow passages. Acoustic behavior as a function of nozzle flow passage geometry was measured. The acoustic data consist primarily of 1/3 octave band sound pressure levels and overall sound pressure levels. Detailed schematics and geometric characteristics of the six scale model nozzle configurations and acoustic test point definitions are presented. Tabulation of aerodynamic test conditions and a computer listing of the measured acoustic data are displayed.

Dietary and urinary metabonomic factors possibly accounting for higher blood pressure of black compared with white Americans: results of International Collaborative Study on macro-/micronutrients and blood pressure.

PubMed

Stamler, Jeremiah; Brown, Ian J; Yap, Ivan K S; Chan, Queenie; Wijeyesekera, Anisha; Garcia-Perez, Isabel; Chadeau-Hyam, Marc; Ebbels, Timothy M D; De Iorio, Maria; Posma, Joram; Daviglus, Martha L; Carnethon, Mercedes; Holmes, Elaine; Nicholson, Jeremy K; Elliott, Paul

2013-12-01

Black compared with non-Hispanic white Americans have higher systolic and diastolic blood pressure and rates of prehypertension/hypertension. Reasons for these adverse findings remain obscure. Analyses here focused on relations of foods/nutrients/urinary metabolites and higher black blood pressure for 369 black compared with 1190 non-Hispanic white Americans aged 40 to 59 years from 8 population samples. Multiple linear regression, standardized data from four 24-hour dietary recalls per person, two 24-hour urine collections, and 8 blood pressure measurements were used to quantitate the role of foods, nutrients, and metabolites in higher black blood pressure. Compared with non-Hispanic white Americans, blacks' average systolic/diastolic pressure was higher by 4.7/3.4 mm Hg (men) and 9.0/4.8 mm Hg (women). Control for higher body mass index of black women reduced excess black systolic/diastolic pressure to 6.8/3.8 mm Hg. Lesser intake of vegetables, fruits, grains, vegetable protein, glutamic acid, starch, fiber, minerals, and potassium, and higher intake of processed meats, pork, eggs, and sugar-sweetened beverages, along with higher cholesterol and higher Na/K ratio, related to in higher black blood pressure. Control for 11 nutrient and 10 non-nutrient correlates reduced higher black systolic/diastolic pressure to 2.3/2.3 mm Hg (52% and 33% reduction in men) and to 5.3/2.8 mm Hg (21% and 27% reduction in women). Control for foods/urinary metabolites had little further influence on higher black blood pressure. Less favorable multiple nutrient intake by blacks than non-Hispanic white Americans accounted, at least in part, for higher black blood pressure. Improved dietary patterns can contribute to prevention/control of more adverse black blood pressure levels.

Performance of an Active Noise Control System for Fan Tones Using Vane Actuators

NASA Technical Reports Server (NTRS)

Sutliff, Daniel L.; Curtis, Alan R. D.; Heidelberg, Laurence J.; Remington, Paul J.

2000-01-01

An Active Noise Control (ANC) system for ducted fan noise was built that uses actuators located in stator vanes. The custom designed actuators A,ere piezoelectric benders manufactured using THUNDER technology. The ANC system was tested in the NASA Active Noise Control Fan rig. A total of 168 actuators in 28 stator vanes were used (six per vane). Simultaneous inlet and exhaust acoustic power level reductions were demonstrated for a fan modal structure that contained two radial modes in each direction. Total circumferential mode power levels were reduced by up to 9 dB in the inlet and 3 dB in the exhaust. The corresponding total 2BPF tone level reductions were by 6 dB in the inlet and 2 dB in the exhaust. Farfield sound pressure level reductions of up to 17 dB were achieved at the peak mode lobe angle. The performance of the system was limited by the constraints of the power amplifiers and the presence of control spillover. Simpler control/actuator systems using carefully selected subsets of the full system and random simulated failures of up to 7% of the actuators were investigated. (The actuators were robust and none failed during the test). Useful reductions still occurred under these conditions.

A research program to reduce interior noise in general aviation airplanes: Investigation of the characteristics of an acoustic panel test facility

NASA Technical Reports Server (NTRS)

Grosveld, F.; Vanaken, J.

1978-01-01

Sound pressure levels in the test facility were studied that are caused by varying: (1) microphone positions; (2) equalizer setting; and (3) panel clamping forces. Measurements were done by using a Beranek tube or this Beranek tube in combinations with an extension tube and a special test section. In all configurations tests were executed with and without a test panel installed. The influence of the speaker back panel and the back panel of the Beranek tube on the sound pressure levels inside the test tube were also investigated. It is shown that the definition of noise reduction is more useful in relation to this test facility than transmission loss.

Myosin light chain phosphorylation is critical for adaptation to cardiac stress.

PubMed

Warren, Sonisha A; Briggs, Laura E; Zeng, Huadong; Chuang, Joyce; Chang, Eileen I; Terada, Ryota; Li, Moyi; Swanson, Maurice S; Lecker, Stewart H; Willis, Monte S; Spinale, Francis G; Maupin-Furlowe, Julie; McMullen, Julie R; Moss, Richard L; Kasahara, Hideko

2012-11-27

Cardiac hypertrophy is a common response to circulatory or neurohumoral stressors as a mechanism to augment contractility. When the heart is under sustained stress, the hypertrophic response can evolve into decompensated heart failure, although the mechanism(s) underlying this transition remain largely unknown. Because phosphorylation of cardiac myosin light chain 2 (MLC2v), bound to myosin at the head-rod junction, facilitates actin-myosin interactions and enhances contractility, we hypothesized that phosphorylation of MLC2v plays a role in the adaptation of the heart to stress. We previously identified an enzyme that predominantly phosphorylates MLC2v in cardiomyocytes, cardiac myosin light-chain kinase (cMLCK), yet the role(s) played by cMLCK in regulating cardiac function in health and disease remain to be determined. We found that pressure overload induced by transaortic constriction in wild-type mice reduced phosphorylated MLC2v levels by ≈40% and cMLCK levels by ≈85%. To examine how a reduction in cMLCK and the corresponding reduction in phosphorylated MLC2v affect function, we generated Mylk3 gene-targeted mice and transgenic mice overexpressing cMLCK specifically in cardiomyocytes. Pressure overload led to severe heart failure in cMLCK knockout mice but not in mice with cMLCK overexpression in which cMLCK protein synthesis exceeded degradation. The reduction in cMLCK protein during pressure overload was attenuated by inhibition of ubiquitin-proteasome protein degradation systems. Our results suggest the novel idea that accelerated cMLCK protein turnover by the ubiquitin-proteasome system underlies the transition from compensated hypertrophy to decompensated heart failure as a result of reduced phosphorylation of MLC2v.

Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure: randomised controlled trial.

PubMed

Slagman, Maartje C J; Waanders, Femke; Hemmelder, Marc H; Woittiez, Arend-Jan; Janssen, Wilbert M T; Lambers Heerspink, Hiddo J; Navis, Gerjan; Laverman, Gozewijn D

2011-07-26

To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE) inhibition at maximum dose. Multicentre crossover randomised controlled trial. Outpatient clinics in the Netherlands. 52 patients with non-diabetic nephropathy. All patients were treated during four 6 week periods, in random order, with angiotensin receptor blockade (valsartan 320 mg/day) or placebo, each combined with, consecutively, a low sodium diet (target 50 mmol Na(+)/day) and a regular sodium diet (target 200 mmol Na(+)/day), with a background of ACE inhibition (lisinopril 40 mg/day) during the entire study. The drug interventions were double blind; the dietary interventions were open label. The primary outcome measure was proteinuria; the secondary outcome measure was blood pressure. Mean urinary sodium excretion, a measure of dietary sodium intake, was 106 (SE 5) mmol Na(+)/day during a low sodium diet and 184 (6) mmol Na(+)/day during a regular sodium diet (P<0.001). Geometric mean residual proteinuria was 1.68 (95% confidence interval 1.31 to 2.14) g/day during ACE inhibition plus a regular sodium diet. Addition of angiotensin receptor blockade to ACE inhibition reduced proteinuria to 1.44 (1.07 to 1.93) g/day (P=0.003), addition of a low sodium diet reduced it to 0.85 (0.66 to 1.10) g/day (P<0.001), and addition of angiotensin receptor blockade plus a low sodium diet reduced it to 0.67 (0.50 to 0.91) g/day (P<0.001). The reduction of proteinuria by the addition of a low sodium diet to ACE inhibition (51%, 95% confidence interval 43% to 58%) was significantly larger (P<0.001) than the reduction of proteinuria by the addition of angiotensin receptor blockade to ACE inhibition (21%, (8% to 32%) and was comparable (P=0.009, not significant after Bonferroni correction) to the reduction of proteinuria by the addition of both angiotensin receptor blockade and a low sodium diet to ACE inhibition (62%, 53% to 70%). Mean systolic blood pressure was 134 (3) mm Hg during ACE inhibition plus a regular sodium diet. Mean systolic blood pressure was not significantly altered by the addition of angiotensin receptor blockade (131 (3) mm Hg; P=0.12) but was reduced by the addition of a low sodium diet (123 (2) mm Hg; P<0.001) and angiotensin receptor blockade plus a low sodium diet (121 (3) mm Hg; P<0.001) to ACE inhibition. The reduction of systolic blood pressure by the addition of a low sodium diet (7% (SE 1%)) was significantly larger (P=0.003) than the reduction of systolic blood pressure by the addition of angiotensin receptor blockade (2% (1)) and was similar (P=0.14) to the reduction of systolic blood pressure by the addition of both angiotensin receptor blockade and low sodium diet (9% (1)), to ACE inhibition. Dietary sodium restriction to a level recommended in guidelines was more effective than dual blockade for reduction of proteinuria and blood pressure in non-diabetic nephropathy. The findings support the combined endeavours of patients and health professionals to reduce sodium intake. Trial registration Netherlands Trial Register NTR675.

Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure: randomised controlled trial

PubMed Central

Slagman, Maartje C J; Waanders, Femke; Hemmelder, Marc H; Woittiez, Arend-Jan; Janssen, Wilbert M T; Lambers Heerspink, Hiddo J; Navis, Gerjan

2011-01-01

Objective To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE) inhibition at maximum dose. Design Multicentre crossover randomised controlled trial. Setting Outpatient clinics in the Netherlands. Participants 52 patients with non-diabetic nephropathy. Interventions All patients were treated during four 6 week periods, in random order, with angiotensin receptor blockade (valsartan 320 mg/day) or placebo, each combined with, consecutively, a low sodium diet (target 50 mmol Na+/day) and a regular sodium diet (target 200 mmol Na+/day), with a background of ACE inhibition (lisinopril 40 mg/day) during the entire study. The drug interventions were double blind; the dietary interventions were open label. Main outcome measures The primary outcome measure was proteinuria; the secondary outcome measure was blood pressure. Results Mean urinary sodium excretion, a measure of dietary sodium intake, was 106 (SE 5) mmol Na+/day during a low sodium diet and 184 (6) mmol Na+/day during a regular sodium diet (P<0.001). Geometric mean residual proteinuria was 1.68 (95% confidence interval 1.31 to 2.14) g/day during ACE inhibition plus a regular sodium diet. Addition of angiotensin receptor blockade to ACE inhibition reduced proteinuria to 1.44 (1.07 to 1.93) g/day (P=0.003), addition of a low sodium diet reduced it to 0.85 (0.66 to 1.10) g/day (P<0.001), and addition of angiotensin receptor blockade plus a low sodium diet reduced it to 0.67 (0.50 to 0.91) g/day (P<0.001). The reduction of proteinuria by the addition of a low sodium diet to ACE inhibition (51%, 95% confidence interval 43% to 58%) was significantly larger (P<0.001) than the reduction of proteinuria by the addition of angiotensin receptor blockade to ACE inhibition (21%, (8% to 32%) and was comparable (P=0.009, not significant after Bonferroni correction) to the reduction of proteinuria by the addition of both angiotensin receptor blockade and a low sodium diet to ACE inhibition (62%, 53% to 70%). Mean systolic blood pressure was 134 (3) mm Hg during ACE inhibition plus a regular sodium diet. Mean systolic blood pressure was not significantly altered by the addition of angiotensin receptor blockade (131 (3) mm Hg; P=0.12) but was reduced by the addition of a low sodium diet (123 (2) mm Hg; P<0.001) and angiotensin receptor blockade plus a low sodium diet (121 (3) mm Hg; P<0.001) to ACE inhibition. The reduction of systolic blood pressure by the addition of a low sodium diet (7% (SE 1%)) was significantly larger (P=0.003) than the reduction of systolic blood pressure by the addition of angiotensin receptor blockade (2% (1)) and was similar (P=0.14) to the reduction of systolic blood pressure by the addition of both angiotensin receptor blockade and low sodium diet (9% (1)), to ACE inhibition. Conclusions Dietary sodium restriction to a level recommended in guidelines was more effective than dual blockade for reduction of proteinuria and blood pressure in non-diabetic nephropathy. The findings support the combined endeavours of patients and health professionals to reduce sodium intake. Trial registration Netherlands Trial Register NTR675. PMID:21791491

Noise reduction of pneumatic nailers of up to 8 bar working pressure, considering handling properties and service life

NASA Astrophysics Data System (ADS)

Damberg, W.; Floegel, K.; Sahm, A.

1983-02-01

A noise reduction device for pneumatic nailers was developed. Conditions of use, range of products available, market regulations and measuring methods were studied. Ease of operation, service life, functional reliability and maintenance capacity were studied. Results show that the essential noise sources of the device are the compressed air blasts of the working and relation phases and the impact of the piston on the bumper. Packages of measures implemented on a laboratory scale indicate noise reduction possibilities for nailers in the short, medium and long term. The sound level of a single shot can be reduced from 110 dB to 93 dB.

The effect of deep-tissue massage therapy on blood pressure and heart rate.

PubMed

Kaye, Alan David; Kaye, Aaron J; Swinford, Jan; Baluch, Amir; Bawcom, Brad A; Lambert, Thomas J; Hoover, Jason M

2008-03-01

In the present study, we describe the effects of deep tissue massage on systolic, diastolic, and mean arterial blood pressure. The study involved 263 volunteers (12% males and 88% females), with an average age of 48.5. Overall muscle spasm/muscle strain was described as either moderate or severe for each patient. Baseline blood pressure and heart rate were measured via an automatic blood pressure cuff. Twenty-one (21) different soothing CDs played in the background as the deep tissue massage was performed over the course of the study. The massages were between 45 and 60 minutes in duration. The data were analyzed using analysis of variance with post-hoc Scheffe's F-test. Results of the present study demonstrated an average systolic pressure reduction of 10.4 mm Hg (p<0.06), a diastolic pressure reduction of 5.3 mm Hg (p<0.04), a mean arterial pressure reduction of 7.0 mm Hg (p<0.47), and an average heart rate reduction of 10.8 beats per minute (p<0.0003), respectively. Additional scientific research in this area is warranted.

Dietary fiber and blood pressure control.

PubMed

Aleixandre, A; Miguel, M

2016-04-01

In the past few years, new strategies to control blood pressure levels are emerging by developing new bioactive components of foods. Fiber has been linked to the prevention of a number of cardiovascular diseases and disorders. β-Glucan, the main soluble fiber component in oat grains, was initially linked to a reduction in plasma cholesterol. Several studies have shown afterward that dietary fiber may also improve glycaemia, insulin resistance and weight loss. The effect of dietary fiber on arterial blood pressure has been the subject of far fewer studies than its effect on the above-mentioned variables, but research has already shown that fiber intake can decrease arterial blood pressure in hypertensive rats. Moreover, certain fibers can improve arterial blood pressure when administered to hypertensive and pre-hypertensive subjects. The present review summarizes all those studies which attempt to establish the antihypertensive effects of dietary fiber, as well as its effect on other cardiovascular risk factors.

SGLT2 inhibitors: their potential reduction in blood pressure.

PubMed

Maliha, George; Townsend, Raymond R

2015-01-01

The sodium glucose co-transporter 2 (SGLT2) inhibitors represent a promising treatment option for diabetes and its common comorbidity, hypertension. Emerging data suggests that the SGLT2 inhibitors provide a meaningful reduction in blood pressure, although the precise mechanism of the blood pressure drop remains incompletely elucidated. Based on current data, the blood pressure reduction is partially due to a combination of diuresis, nephron remodeling, reduction in arterial stiffness, and weight loss. While current trials are underway focusing on cardiovascular endpoints, the SGLT2 inhibitors present a novel treatment modality for diabetes and its associated hypertension as well as an opportunity to elucidate the pathophysiology of hypertension in diabetes. Copyright © 2015 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

Antihypertensive treatment differentially affects vascular sphingolipid biology in spontaneously hypertensive rats.

PubMed

Spijkers, Léon J A; Janssen, Ben J A; Nelissen, Jelly; Meens, Merlijn J P M T; Wijesinghe, Dayanjan; Chalfant, Charles E; De Mey, Jo G R; Alewijnse, Astrid E; Peters, Stephan L M

2011-01-01

We have previously shown that essential hypertension in humans and spontaneously hypertensive rats (SHR), is associated with increased levels of ceramide and marked alterations in sphingolipid biology. Pharmacological elevation of ceramide in isolated carotid arteries of SHR leads to vasoconstriction via a calcium-independent phospholipase A(2), cyclooxygenase-1 and thromboxane synthase-dependent release of thromboxane A(2). This phenomenon is almost absent in vessels from normotensive Wistar Kyoto (WKY) rats. Here we investigated whether lowering of blood pressure can reverse elevated ceramide levels and reduce ceramide-mediated contractions in SHR. For this purpose SHR were treated for 4 weeks with the angiotensin II type 1 receptor antagonist losartan or the vasodilator hydralazine. Both drugs decreased blood pressure equally (SBP untreated SHR: 191±7 mmHg, losartan: 125±5 mmHg and hydralazine: 113±14 mmHg). The blood pressure lowering was associated with a 20-25% reduction in vascular ceramide levels and improved endothelial function of isolated carotid arteries in both groups. Interestingly, losartan, but not hydralazine treatment, markedly reduced sphingomyelinase-induced contractions. While both drugs lowered cyclooxygenase-1 expression, only losartan and not hydralazine, reduced the endothelial expression of calcium-independent phospholipase A(2). The latter finding may explain the effect of losartan treatment on sphingomyelinase-induced vascular contraction. In summary, this study corroborates the importance of sphingolipid biology in blood pressure control and specifically shows that blood pressure lowering reduces vascular ceramide levels in SHR and that losartan treatment, but not blood pressure lowering per se, reduces ceramide-mediated arterial contractions.

Antihypertensive Treatment Differentially Affects Vascular Sphingolipid Biology in Spontaneously Hypertensive Rats

PubMed Central

Spijkers, Léon J. A.; Janssen, Ben J. A.; Nelissen, Jelly; Meens, Merlijn J. P. M. T.; Wijesinghe, Dayanjan; Chalfant, Charles E.; De Mey, Jo G. R.; Alewijnse, Astrid E.; Peters, Stephan L. M.

2011-01-01

Background We have previously shown that essential hypertension in humans and spontaneously hypertensive rats (SHR), is associated with increased levels of ceramide and marked alterations in sphingolipid biology. Pharmacological elevation of ceramide in isolated carotid arteries of SHR leads to vasoconstriction via a calcium-independent phospholipase A2, cyclooxygenase-1 and thromboxane synthase-dependent release of thromboxane A2. This phenomenon is almost absent in vessels from normotensive Wistar Kyoto (WKY) rats. Here we investigated whether lowering of blood pressure can reverse elevated ceramide levels and reduce ceramide-mediated contractions in SHR. Methods and Findings For this purpose SHR were treated for 4 weeks with the angiotensin II type 1 receptor antagonist losartan or the vasodilator hydralazine. Both drugs decreased blood pressure equally (SBP untreated SHR: 191±7 mmHg, losartan: 125±5 mmHg and hydralazine: 113±14 mmHg). The blood pressure lowering was associated with a 20–25% reduction in vascular ceramide levels and improved endothelial function of isolated carotid arteries in both groups. Interestingly, losartan, but not hydralazine treatment, markedly reduced sphingomyelinase-induced contractions. While both drugs lowered cyclooxygenase-1 expression, only losartan and not hydralazine, reduced the endothelial expression of calcium-independent phospholipase A2. The latter finding may explain the effect of losartan treatment on sphingomyelinase-induced vascular contraction. Conclusion In summary, this study corroborates the importance of sphingolipid biology in blood pressure control and specifically shows that blood pressure lowering reduces vascular ceramide levels in SHR and that losartan treatment, but not blood pressure lowering per se, reduces ceramide-mediated arterial contractions. PMID:22195025

Active control of fan noise from a turbofan engine

NASA Technical Reports Server (NTRS)

Thomas, Russell H.; Burdisso, Ricardo A.; Fuller, Christopher R.; O'Brien, Walter F.

1994-01-01

A three-channel active control system is applied to an operational turbofan engine to reduce tonal noise produced by both the fan and the high-pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provide blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. To minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three-channel controller by up to 16 dB over a +/- 30-deg angle about the engine axis. A single-channel controller could produce reduction over a +/- 15-deg angle. The experimental results show the control to be robust. Outside of the areas contolled, the levels of the tone actually increased due to the generation of radial modes by the control sources. Simultaneous control of two tones is achieved with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high-pressure compressor fundamental tones.

Long-term effects of a plant-based dietary portfolio of cholesterol-lowering foods on blood pressure.

PubMed

Jenkins, D J A; Kendall, C W C; Faulkner, D A; Kemp, T; Marchie, A; Nguyen, T H; Wong, J M W; de Souza, R; Emam, A; Vidgen, E; Trautwein, E A; Lapsley, K G; Josse, R G; Leiter, L A; Singer, W

2008-06-01

To determine the effect on blood pressure of dietary advice to consume a combination of plant-based cholesterol-lowering foods (dietary portfolio). For 1 year, 66 hyperlipidemic subjects were prescribed diets high in plant sterols (1.0 g/1000 kcal), soy protein (22.5 g/1000 kcal), viscous fibers (10 g/1000 kcal) and almonds (22.5 g/1000 kcal). There was no control group. Seven-day diet record, blood pressure and body weight were monitored initially monthly and later at 2-monthly intervals throughout the study. Fifty subjects completed the 1-year study. When the last observation was carried forward for non-completers (n=9) or those who changed their blood pressure medications (n=7), a small mean reduction was seen in body weight 0.7+/-0.3 kg (P=0.036). The corresponding reductions from baseline in systolic and diastolic blood pressure at 1 year (n=66 subjects) were -4.2+/-1.3 mm Hg (P=0.002) and -2.3+/-0.7 mm Hg (P=0.001), respectively. Blood pressure reductions occurred within the first 2 weeks, with stable blood pressures 6 weeks before and 4 weeks after starting the diet. Diastolic blood pressure reduction was significantly related to weight change (r=0.30, n=50, P=0.036). Only compliance with almond intake advice related to blood pressure reduction (systolic: r=-0.34, n=50, P=0.017; diastolic: r=-0.29, n=50, P=0.041). A dietary portfolio of plant-based cholesterol-lowering foods reduced blood pressure significantly, related to almond intake. The dietary portfolio approach of combining a range of cholesterol-lowering plant foods may benefit cardiovascular disease risk both by reducing serum lipids and also blood pressure.

Augmentor emissions reduction technology program. [for turbofan engines

NASA Technical Reports Server (NTRS)

Colley, W. C.; Kenworthy, M. J.; Bahr, D. W.

1977-01-01

Technology to reduce pollutant emissions from duct-burner-type augmentors for use on advanced supersonic cruise aircraft was investigated. Test configurations, representing variations of two duct-burner design concepts, were tested in a rectangular sector rig at inlet temperature and pressure conditions corresponding to takeoff, transonic climb, and supersonic cruise flight conditions. Both design concepts used piloted flameholders to stabilize combustion of lean, premixed fuel/air mixtures. The concepts differed in the flameholder type used. High combustion efficiency (97%) and low levels of emissions (1.19 g/kg fuel) were achieved. The detailed measurements suggested the direction that future development efforts should take to obtain further reductions in emission levels and associated improvements in combustion efficiency over an increased range of temperature rise conditions.

Effects of combination of aliskiren and pentoxyfylline on renal function in the rat remnant kidney model of chronic renal failure.

PubMed

Soni, Hitesh M; Patel, Praful P; Patel, Savan; Rath, Akshyaya C; Acharya, Aviseka; Trivedi, Harshkant D; Jain, Mukul R

2015-01-01

The aim was to investigate the nephroprotective effect of combination of aliskiren (ASK), a direct renin inhibitor and pentoxifylline (PTX), inhibitor of tumor necrotic factor-alpha (TNF-alpha), in rat remnant kidney model of chronic kidney disease (CKD). Nephrectomized (NPX) rats were treated with ASK (10 mg/kg, p.o.), PTX (100 mg/kg, p.o.), and combination of PTX + ASK once daily for 28 days. We have performed analysis of various renal injury parameters after 4 weeks of treatment. Treatment with PTX, ASK and combination showed significant improvement in urea, creatinine and total protein in plasma when compared with vehicle treated group in NPX rats. ASK and combination of PTX + ASK elicited significant reduction in blood pressure but PTX alone did not produce blood pressure reduction. ASK treatment showed significant elevation in TNF-alpha, whereas PTX and ASK + PTX showed significant reduction in TNF-alpha in plasma. Histopathologically, the extent of the kidney injury was similar in NPX + vehicle and NPX + ASK-treated rats. PTX and ASK + PTX-treated group showed lesser extent of kidney injury. There was good correlation of mRNA expression levels of kidney injury molecule-1 and bradykinin B1 receptor data with histopathological findings in kidney samples and elevated TNF-alpha levels in plasma. We conclude that combination of PTX + ASK may be better therapeutic intervention for nephroprotection in CKD patients.

European EVA decompression sickness risks

NASA Astrophysics Data System (ADS)

Vogt, Lorenz; Wenzel, Jürgen; Skoog, A. I.; Luck, S.; Svensson, Bengt

For the first manned flight of Hermes there will be a capability of performing EVA. The European EVA Space Suit will be an anthropomorphic system with an internal pressure of 500 hPa of pure oxygen. The pressure reduction from the Hermes cabin pressure of 1013 hPa will induce a risk for Decompression Sickness (DCS) for the EVA crewmember if no adequate protective procedures are implemented. Specific decompression procedures have to be developed. From a critical review of the literature and by using knowledge gained from research conducted in the past in the fields of diving and aerospace medicine safe protective procedures are proposed for the European EVA scenario. An R factor of 1.2 and a tissue half-time ( t1/2) of 360 minutes in a single-tissue model have been identified as appropriate operational values. On the basis of an acceptable risk level of approximately 1%, oxygen prebreathing times are proposed for (a) direct pressure reduction from 1013 hPa to a suit pressure of 500 hPa, and (b) staged decompression using a 700 hPa intermediate stage in the spacecraft cabin. In addition, factors which influence individual susceptibility to DCS are identified. Recommendations are also given in the areas of crew selection and medical monitoring requirements together with therapeutic measures that can be implemented in the Hermes scenario. A method for demonstration of the validity of proposed risks and procedures is proposed.

Dual fuel diesel engine operation using LPG

NASA Astrophysics Data System (ADS)

Mirica, I.; Pana, C.; Negurescu, N.; Cernat, Al; Nutu, N. C.

2016-08-01

Diesel engine fuelling with LPG represents a good solution to reduce the pollutant emissions and to improve its energetic performances. The high autoignition endurance of LPG requires specialized fuelling methods. From all possible LPG fuelling methods the authors chose the diesel-gas method because of the following reasons: is easy to be implemented even at already in use engines; the engine does not need important modifications; the LPG-air mixture has a high homogeneity with favorable influences over the combustion efficiency and over the level of the pollutant emissions, especially on the nitrogen oxides emissions. This paper presents results of the theoretical and experimental investigations on operation of a LPG fuelled heavy duty diesel engine at two operating regimens, 40% and 55%. For 55% engine load is also presented the exhaust gas recirculation influence on the pollutant emission level. Was determined the influence of the diesel fuel with LPG substitution ratio on the combustion parameters (rate of heat released, combustion duration, maximum pressure, maximum pressure rise rate), on the energetic parameters (indicate mean effective pressure, effective efficiency, energetic specific fuel consumption) and on the pollutant emissions level. Therefore with increasing substitute ratio of the diesel fuel with LPG are obtained the following results: the increase of the engine efficiency, the decrease of the specific energetic consumption, the increase of the maximum pressure and of the maximum pressure rise rate (considered as criteria to establish the optimum substitute ratio), the accentuated reduction of the nitrogen oxides emissions level.

The effects of listening environment and earphone style on preferred listening levels of normal hearing adults using an MP3 player.

PubMed

Hodgetts, William E; Rieger, Jana M; Szarko, Ryan A

2007-06-01

The main objective of this study was to determine the influence of listening environment and earphone style on the preferred-listening levels (PLLs) measured in users' ear canals with a commercially-available MP3 player. It was hypothesized that listeners would prefer higher levels with earbud headphones as opposed to over-the-ear headphones, and that the effects would depend on the environment in which the user was listening. A secondary objective was to use the measured PLLs to determine the permissible listening duration to reach 100% daily noise dose. There were two independent variables in this study. The first, headphone style, had three levels: earbud, over-the-ear, and over-the-ear with noise reduction (the same headphones with a noise reduction circuit). The second, environment, also had 3 levels: quiet, street noise and multi-talker babble. The dependent variable was ear canal A-weighted sound pressure level. A 3 x 3 within-subjects repeated-measures ANOVA was used to analyze the data. Thirty-eight normal hearing adults were recruited from the Faculty of Rehabilitation Medicine at the University of Alberta. Each subject listened to the same song and adjusted the level until it "sounded best" to them in each of the 9 conditions. Significant main effects were found for both the headphone style and environment factors. On average, listeners had higher preferred listening levels with the earbud headphones, than with the over-the-ear headphones. When the noise reduction circuit was used with the over-the-ear headphones, the average PLL was even lower. On average, listeners had higher PLLs in street noise than in multi-talker babble and both of these were higher than the PLL for the quiet condition. The interaction between headphone style and environment was also significant. Details of individual contrasts are explored. Overall, PLLs were quite conservative, which would theoretically allow for extended permissible listening durations. Finally, we investigated the maximum output level of the MP3 player in the ear canals of authors 1 and 3 of this paper. Levels were highest with the earbud style, followed by the over-the-ear with noise reduction. The over-the-ear headphone without noise reduction had the lowest maximum output. The majority of MP3 players are sold with the earbud style of headphones. Preferred listening levels are higher with this style of headphone compared to the over-the-ear style. Moreover, as the noise level in the environment increases, earbud users are even more susceptible to background noise and consequently increase the level of the music to overcome this. The result is an increased sound pressure level at the eardrum. However, the levels chosen by our subjects suggest that MP3 listening levels may not be as significant a concern as has been reported recently in the mainstream media.

LB01.06: VISIT-TO-VISIT BLOOD PRESSURE VARIABILITY AND CARDIOVASCULAR OUTCOMES IN FELODIPINE EVENT REDUCTION STUDY.

PubMed

Zhang, Y; Zhang, X; Liu, L; Zanchetti, A

2015-06-01

Many antihypertensive outcome trials have shown that visit-to-visit blood pressure variability is correlated closely with clinical outcomes in hypertensive patients. The objective of the study was to investigate the relationship between visit-to-visit blood pressure variability (BPV) and the major cardiovascular outcomes in the Chinese hypertensive patients. Felodipine Event Reduction (FEVER) study was a double-blind, randomized trial on 9711 Chinese hypertensive patients, in whom cardiovascular outcomes were significantly reduced by more intense therapy achieving a mean of 138 mmHg SBP compared with less-intense therapy achieving a mean of 142 mmHg. Visit-to-visit BPV during the follow-up period [defined as standard deviation (SD), coefficient of variation (CV), and average real variability(ARV)] was derived from casual cuff BP measures after six months follow-up until the end of the study. Hazard ratios (HRs), for the incidence of CVD associated with SD, CV, and ARV of SBP and DBP were calculated using Cox proportional hazard models. Overall predictive power [area under receiver operating characteristic (AUC ROC) curve] of the level of blood pressure, blood pressure variability and other baseline characteristics was calculated. In FEVER study, visit-to-visit variability in SBP were significant predictors of subsequent stroke [eg, hazard ratios [HR] for ARV, SD and CV was 1.071 (95% CI: 1.025-1.118), 1.373 (95% CI: 1.159-1.626) and 0.572 (95% CI: 0.451-0,726)]. Visit-to-visit variability in DBP were also showed similar trend [eg, HR for ARV, SD and CV was 1.066 (95% CI: 0.992-1.145), 1.931 (95% CI: 1.435-2.598) and 0.558 (95% CI: 0.438-0,710)]. However, using the analysis of AUC ROC analysis, the risk importance sequence of the stroke events in this cohort was level of SBP, age, level of DBP ARV, SD, sex, CV and treatment. Visit-to-visit blood pressure variability has some effects on the cardiovascular outcomes in the Chinese hypertensive patents in the cohort in FEVER Study. However, blood pressure per se is even more important for the development of stroke in this group of patients.

Intensive versus conventional blood pressure monitoring in a general practice population. The Blood Pressure Reduction in Danish General Practice trial: a randomized controlled parallel group trial.

PubMed

Klarskov, Pia; Bang, Lia E; Schultz-Larsen, Peter; Gregers Petersen, Hans; Benee Olsen, David; Berg, Ronan M G; Abrahamsen, Henrik; Wiinberg, Niels

2018-01-17

To compare the effect of a conventional to an intensive blood pressure monitoring regimen on blood pressure in hypertensive patients in the general practice setting. Randomized controlled parallel group trial with 12-month follow-up. One hundred and ten general practices in all regions of Denmark. One thousand forty-eight patients with essential hypertension. Conventional blood pressure monitoring ('usual group') continued usual ad hoc blood pressure monitoring by office blood pressure measurements, while intensive blood pressure monitoring ('intensive group') supplemented this with frequent home blood pressure monitoring and 24-hour ambulatory blood pressure monitoring. Mean day- and night-time systolic and diastolic 24-hour ambulatory blood pressure. Change in systolic and diastolic office blood pressure and change in cardiovascular risk profile. Of the patients, 515 (49%) were allocated to the usual group, and 533 (51%) to the intensive group. The reductions in day- and night-time 24-hour ambulatory blood pressure were similar (usual group: 4.6 ± 13.5/2.8 ± 82 mmHg; intensive group: 5.6 ± 13.0/3.5 ± 8.2 mmHg; P = 0.27/P = 0.20). Cardiovascular risk scores were reduced in both groups at follow-up, but more so in the intensive than in the usual group (P = 0.02). An intensive blood pressure monitoring strategy led to a similar blood pressure reduction to conventional monitoring. However, the intensive strategy appeared to improve patients' cardiovascular risk profile through other effects than a reduction of blood pressure. Clinical Trials NCT00244660. © The Author 2018. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Beneficial effects of renal sympathetic denervation on cardiovascular inflammation and remodeling in essential hypertension.

PubMed

Dörr, Oliver; Liebetrau, Christoph; Möllmann, Helge; Mahfoud, Felix; Ewen, Sebastian; Gaede, Luise; Troidl, Christian; Hoffmann, Jedrzej; Busch, Nikolai; Laux, Gerald; Wiebe, Jens; Bauer, Timm; Hamm, Christian; Nef, Holger

2015-02-01

Renal sympathetic denervation (RSD) represents a potential treatment option for certain patients with resistant arterial hypertension (HT). HT is associated with chronic vascular inflammation and remodeling, contributing to progressive vascular damage, and atherosclerosis. The present study aimed to evaluate the influence of RSD on cardiovascular inflammation and remodeling by determining serum levels of interleukin-6 (IL-6), high-sensitive C-reactive protein (hsCRP), matrix metalloproteinases (MMP), and tissue inhibitor of metalloproteinases (TIMP). A total of 60 consecutive patients (age 67.9 ± 9.6 years) undergoing RSD were included. A therapeutic response was defined as an office systolic blood pressure (SBP) reduction of >10 mmHg 6 months after RSD. Venous serum samples for measurement of hsCRP, IL-6, MMP-2, MMP-9, and TIMP-1 were collected prior to and 6 months after RSD. A significant reduction in office SBP of 26.4 mmHg [SBPbaseline 169.3 mmHg (SD 11.3), p < 0.001] was documented 6 months after RSD. The serum levels of hsCRP (p < 0.001) and the pro-inflammatory cytokine IL-6 (p < 0.001) were significantly decreased compared to baseline values. The levels of MMP-9 (p = 0.024) and MMP-2 (p < 0.01) were significantly increased compared to baseline values. In addition to the effective blood pressure reduction in response to RSD, this study demonstrates a positive effect of RSD on biomarkers reflecting vascular inflammation and remodeling. These results suggest a possible prognostic benefit of RSD in high-risk patients for endothelial dysfunction and cardiovascular remodeling as well as end-organ damage.

Experimental Study of a Three-Dimensional Shear-Driven Turbulent Boundary Layer with Streamwise Adverse Pressure Gradient

NASA Technical Reports Server (NTRS)

Driver, David M.; Johnston, James P.

1990-01-01

The effects of a strong adverse pressure gradient on a three-dimensional turbulent boundary layer are studied in an axisymmetric spinning cylinder geometry. Velocity measurements made with a three-component laser Doppler velocimeter include all three mean flow components, all six Reynolds stress components, and all ten triple-product correlations. Reynolds stress diminishes as the flow becomes three-dimensional. Lower levels of shear stress were seen to persist under adverse pressure gradient conditions. This low level of stress was seen to roughly correlate with the magnitude of cross-flow (relative to free stream flow) for this experiment as well as most of the other experiments in the literature. Variations in pressure gradient do not appear to alter this correlation. For this reason, it is hypothesized that a three-dimensional boundary layer is more prone to separate than a two-dimensional boundary layer, although it could not be directly shown here. None of the computations performed with either a Prandtl mixing length, k-epsilon, or a Launder-Reece-Rodi full Reynolds-stress model were able to predict the reduction in Reynolds stress.

The role of dietary potassium in hypertension and diabetes.

PubMed

Ekmekcioglu, Cem; Elmadfa, Ibrahim; Meyer, Alexa L; Moeslinger, Thomas

2016-03-01

Potassium is an essential mineral which plays major roles for the resting membrane potential and the intracellular osmolarity. In addition, for several years, it has been known that potassium also affects endothelial and vascular smooth muscle functions and it has been repeatedly shown that an increase in potassium intake shifts blood pressure to a more preferable level. Meanwhile, the blood pressure lowering effects of potassium were presented in several intervention trials and summarized in a handful of meta-analyses. Furthermore, accumulating epidemiological evidence from, especially, the last decade relates low dietary potassium intake or serum potassium levels to an increased risk for insulin resistance or diabetes. However, intervention trials are required to confirm this association. So, in addition to reduction of sodium intake, increasing dietary potassium intake may positively affect blood pressure and possibly also glucose metabolism in many populations. This concise review not only summarizes the studies linking potassium to blood pressure and diabetes but also discusses potential mechanisms involved, like vascular smooth muscle relaxation and endothelium-dependent vasodilation or stimulation of insulin secretion in pancreatic β-cells, respectively.

49 CFR 236.554 - Rate of pressure reduction; equalizing reservoir or brake pipe.

Code of Federal Regulations, 2011 CFR

2011-10-01

... GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Rules and Instructions... pressure or brake-pipe pressure reduction during an automatic brake application shall be at a rate not less...

49 CFR 236.554 - Rate of pressure reduction; equalizing reservoir or brake pipe.

Code of Federal Regulations, 2010 CFR

2010-10-01

... GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Rules and Instructions... pressure or brake-pipe pressure reduction during an automatic brake application shall be at a rate not less...

Specific features of electron scattering in uniaxially deformed n-Ge single crystals in the presence of radiation defects

NASA Astrophysics Data System (ADS)

Luniov, S. V.; Zimych, A. I.; Nazarchuk, P. F.; Maslyuk, V. T.; Megela, I. G.

2016-12-01

Temperature dependencies for concentration of electrons and the Hall mobility for unirradiated and irradiated by the flow of electrons ? single crystals ?, with the energy of ?, for different values of uniaxial pressures along the crystallographic directions ?, ? and ? are obtained on the basis of piezo-Hall effect measurements. Non-typical growth of the Hall mobility of electrons for irradiated single crystals ? in comparison with unirradiated with the increasing of value of uniaxial pressures along the crystallographic directions ? (for the entire range of the investigated temperatures) and ? (to temperatures ?) has been revealed. Such an effect of the Hall mobility increase for uniaxially deformed single crystals ? is explained by the reduction of gradients of a resistance as a result of reduction in the amplitude of a large-scale potential with deformation and concentration of charged A-centers in the process of their recharge by the increasing of uniaxial pressure and consequently the probability of scattering on these centers. Theoretical calculations for temperature dependencies of the Hall mobility for uniaxially deformed single crystals ? in terms of the electrons scattering on the ions of shallow donors, acoustic, optical and intervalley phonons, regions of disordering and large-scale potential is good conformed to the corresponding experimental results at temperatures T<220 K for the case of uniaxial pressures along the crystallographic directions ? and ? and for temperatures ? when the uniaxial pressure is directed along the crystallographic directions ?. The mechanism of electron scattering on a charged radiation defects (which correspond to the deep energy levels of A-centers) 'is turned off' for the given temperatures due to the uniaxial pressure. Reduction of the Hall mobility in transition through a maximum of dependence ? with the increasing temperature for cases of the uniaxial deformation of the irradiated single crystals ? along the crystallographic directions ? and ? is explained by the deforming redistribution of electrons between the minima of conduction band of germanium with different mobility.

Food insecurity and effectiveness of behavioral interventions to reduce blood pressure, New York City, 2012-2013.

PubMed

Grilo, Stephanie A; Shallcross, Amanda J; Ogedegbe, Gbenga; Odedosu, Taiye; Levy, Natalie; Lehrer, Susan; Chaplin, William; Spruill, Tanya M

2015-02-12

Food insecurity is associated with diet-sensitive diseases and may be a barrier to successful chronic disease self-management. To evaluate the impact of food insecurity on blood pressure reduction in a pilot clinical trial, we tested the effectiveness of 2 behavioral interventions for hypertension in people with and without food security. A group of 28 men and women with type 2 diabetes and uncontrolled hypertension were randomized to either 1) home blood pressure telemonitoring alone or 2) home blood pressure telemonitoring plus telephone-based nurse case management. The primary outcome was 6-month change in systolic blood pressure. The 2 interventions resulted in modest, nonsignificant blood pressure reductions. Food-secure patients experienced clinically and statistically significant reductions in blood pressure, whereas no significant change was seen among food-insecure patients. Screening for food insecurity may help identify patients in need of tailored disease management interventions.

Reduction of the incidence of pressure sores by an education program on nursing care.

PubMed

Srisupan, Vijitr; Senaratana, Wilawan; Picheansatian, Wilawan; Chittreecheur, Jittaporn; Watanakool, Malinee; Chaisri, Pratin; Singhakumfu, Laddawan; Tribuddharat, Chanwit; Danchaivijitr, Somwang

2005-12-01

To determine whether an education and campaign program would reduce the incidence of pressure sores. The study was performed in a 1,400-bed teaching hospital in Thailand with a total number of 697patients from 47 wards for a point prevalence study; 1,201 and 1,268 patients from 12 wards to determine whether reduction of pressure sore occurrence would be obtained by an education program. The point prevalence of pressure sores was 10.8%. The significant risk factors were age older than 60 years, fecal incontinence, and history of diarrhea. The occurrence of pressure sores was significantly reduced after the educational program from 9.91% to 5. 76%. The education on patient care aiming at reduction of the occurrence of pressure sores could be adopted nation-wide in order to reduce the morbidity, mortality and expenses. The education program was effective in reducing the incidence of pressure sores.

Broadband Noise Reduction of a Low-Speed Fan Noise Using Trailing Edge Blowing

NASA Technical Reports Server (NTRS)

Sutliff, Daniel L.

2005-01-01

An experimental proof-of-concept test was conducted to demonstrate reduction of rotor-stator interaction noise through the use of rotor-trailing edge blowing. The velocity deficit from the viscous wake of the rotor blades was reduced by injecting air into the wake from a continuous trailing edge slot. Hollow blades with interior guide vanes create flow channels through which externally supplied air flows from the blade root to the trailing edge. A previous paper documented the substantial tonal reductions of this Trailing Edge Rotor Blowing (TERB) fan. This report documents the broadband characteristics of TERB. The Active Noise Control Fan (ANCF), located at the NASA Glenn Research Center, was used as the proof-of-concept test bed. Two-component hotwire data behind the rotor, unsteady surface pressures on the stator vane, and farfield directivity acoustic data were acquired at blowing rates of 1.1, 1.5, and 1.8 percent of the total fan mass flow. The results indicate a substantial reduction in the rotor wake turbulent velocity and in the stator vane unsteady surface pressures. Based on the physics of the noise generation, these indirect measurements indicate the prospect of broadband noise reduction. However, since the broadband noise generated by the ANCF is rotor-dominated, any change in the rotor-stator interaction broadband noise levels is barely distinguishable in the farfield measurements.

Dietary Salt Intake and Hypertension

PubMed Central

2014-01-01

Over the past century, salt has been the subject of intense scientific research related to blood pressure elevation and cardiovascular mortalities. Moderate reduction of dietary salt intake is generally an effective measure to reduce blood pressure. However, recently some in the academic society and lay media dispute the benefits of salt restriction, pointing to inconsistent outcomes noted in some observational studies. A reduction in dietary salt from the current intake of 9-12 g/day to the recommended level of less than 5-6 g/day will have major beneficial effects on cardiovascular health along with major healthcare cost savings around the world. The World Health Organization (WHO) strongly recommended to reduce dietary salt intake as one of the top priority actions to tackle the global non-communicable disease crisis and has urged member nations to take action to reduce population wide dietary salt intake to decrease the number of deaths from hypertension, cardiovascular disease and stroke. However, some scientists still advocate the possibility of increased risk of CVD morbidity and mortality at extremes of low salt intake. Future research may inform the optimal sodium reduction strategies and intake targets for general populations. Until then, we have to continue to build consensus around the greatest benefits of salt reduction for CVD prevention, and dietary salt intake reduction strategies must remain at the top of the public health agenda. PMID:25061468

Minimizing noise in fiberglass aquaculture tanks: Noise reduction potential of various retrofits

USGS Publications Warehouse

Davidson, J.; Frankel, A.S.; Ellison, W.T.; Summerfelt, S.; Popper, A.N.; Mazik, P.; Bebak, J.

2007-01-01

Equipment used in intensive aquaculture systems, such as pumps and blowers can produce underwater sound levels and frequencies within the range of fish hearing. The impacts of underwater noise on fish are not well known, but limited research suggests that subjecting fish to noise could result in impairment of the auditory system, reduced growth rates, and increased stress. Consequently, reducing sound in fish tanks could result in advantages for cultured species and increased productivity for the aquaculture industry. The objective of this study was to evaluate the noise reduction potential of various retrofits to fiberglass fish culture tanks. The following structural changes were applied to tanks to reduce underwater noise: (1) inlet piping was suspended to avoid contact with the tank, (2) effluent piping was disconnected from a common drain line, (3) effluent piping was insulated beneath tanks, and (4) tanks were elevated on cement blocks and seated on insulated padding. Four combinations of the aforementioned structural changes were evaluated in duplicate and two tanks were left unchanged as controls. Control tanks had sound levels of 120.6 dB re 1 ??Pa. Each retrofit contributed to a reduction of underwater sound. As structural changes were combined, a cumulative reduction in sound level was observed. Tanks designed with a combination of retrofits had sound levels of 108.6 dB re 1 ??Pa, a four-fold reduction in sound pressure level. Sound frequency spectra indicated that the greatest sound reductions occurred between 2 and 100 Hz and demonstrated that nearby pumps and blowers created tonal frequencies that were transmitted into the tanks. The tank modifications used during this study were simple and inexpensive and could be applied to existing systems or considered when designing aquaculture facilities. ?? 2007 Elsevier B.V. All rights reserved.

High-pressure processing of apple juice: kinetics of pectin methyl esterase inactivation.

PubMed

Riahi, Esmaeil; Ramaswamy, Hosahalli S

2003-01-01

High-pressure (HP) inactivation kinetics of pectin methyl esterase (PME) in apple juice were evaluated. Commercial PME was dispensed in clarified apple juice, sealed in dual peel sterilizable plastic bags, and subjected to different high-pressure processing conditions (200-400 MPa, 0-180 min). Residual enzyme activity was determined by a titration method estimating the rate of free carboxyl group released by the enzyme acting on pectin substrate at pH 7.5 (30 degrees C). The effects of pressure level and pressure holding time on enzyme inactivation were significant (p < 0.05). PME from the microbial source was found to be more resistant (p < 0.05) to pressure inactivation than PME from the orange peel. Almost a full decimal reduction in the activity of commercial PME was achieved by HP treatment at 400 MPa for 25 min. Inactivation kinetics were evaluated on the basis of a dual effect model involving a pressure pulse effect and a first-order rate model, and the pressure sensitivity of rate constants was modeled by using the z-value concept.

Diagnostic and therapeutic approach to the hypertensive crisis.

PubMed

Arbe, Guillermo; Pastor, Irene; Franco, Jonathan

2018-04-23

High blood pressure is a problem with elevated prevalence in the world population. The acute forms of presentation are "hypertensive crises," which represent a frequent cause for emergency room and primary care consultations. Hypertensive crises are divided into hypertensive emergencies and hypertensive urgencies, depending on whether or not there is acute damage to the target organ, respectively. Each situation has a different prognosis and treatment. More specifically, hypertensive emergencies are potentially serious and usually require rapid reductions in blood pressure, whereas hypertensive urgencies can be treated as outpatients by reducing blood pressure in hours or days. A significant number of patients who consult medical professionals regarding a hypertensive crisis do not have a prior diagnosis of hypertension; therefore, it is important to periodically monitor blood pressure levels in the community. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Correlated environmental corrections in TOPEX/POSEIDON, with a note on ionospheric accuracy

NASA Technical Reports Server (NTRS)

Zlotnicki, V.

1994-01-01

Estimates of the effectiveness of an altimetric correction, and interpretation of sea level variability as a response to atmospheric forcing, both depend upon assuming that residual errors in altimetric corrections are uncorrelated among themselves and with residual sea level, or knowing the correlations. Not surprisingly, many corrections are highly correlated since they involve atmospheric properties and the ocean surface's response to them. The full corrections (including their geographically varying time mean values), show correlations between electromagnetic bias (mostly the height of wind waves) and either atmospheric pressure or water vapor of -40%, and between atmospheric pressure and water vapor of 28%. In the more commonly used collinear differences (after removal of the geographically varying time mean), atmospheric pressure and wave height show a -30% correlation, atmospheric pressure and water vapor a -10% correlation, both pressure and water vapor a 7% correlation with residual sea level, and a bit surprisingly, ionospheric electron content and wave height a 15% correlation. Only the ocean tide is totally uncorrelated with other corrections or residual sea level. The effectiveness of three ionospheric corrections (TOPEX dual-frequency, a smoothed version of the TOPEX dual-frequency, and Doppler orbitography and radiopositioning integrated by satellite (DORIS) is also evaluated in terms of their reduction in variance of residual sea level. Smooth (90-200 km along-track) versions of the dual-frequency altimeter ionosphere perform best both globally and within 20 deg in latitude from the equator. The noise variance in the 1/s TOPEX inospheric samples is approximately (11 mm) squared, about the same as noise in the DORIS-based correction; however, the latter has its error over scales of order 10(exp 3) km. Within 20 deg of the equator, the DORIS-based correction adds (14 mm) squared to the residual sea level variance.

Do improvements in dietary behaviour contribute to cardiovascular risk factor reduction over and above cardio-protective medication in newly diagnosed diabetes patients?

PubMed

Cooper, A J M; Schliemann, D; Long, G H; Griffin, S J; Simmons, R K

2014-10-01

A healthy diet is an integral component of successful diabetes management. However, the comparative importance of adopting a healthy diet for cardiovascular risk factor reduction over and above medication use among newly diagnosed diabetes patients remains unclear. We computed a dietary score consistent with American Diabetes Association and Diabetes UK recommendations in 574 newly diagnosed diabetes patients by summing standardised values for the intake of total energy, saturated fat, sodium, fibre and plasma vitamin C. In linear regression analyses, stratified by cardio-protective medication use (yes/no), we quantified the comparative longitudinal associations of baseline diet and change in diet over 1 year with change in blood pressure, HbA1c and lipids. Baseline diet was generally not predictive of change in cardiovascular risk factor levels at 1 year. In contrast, dietary change over 1 year among patients prescribed and not prescribed cardio-protective medication after baseline was associated with comparative (p-interaction all ⩾0.95) reductions in diastolic blood pressure (-2.38 vs -2.93 mm Hg, respectively) and triglycerides (-0.31 vs -0.21 mmol/l, respectively), independent of potential confounding factors and change from baseline to follow-up in physical activity and smoking status. Modest dietary change over the first year following diagnosis of diabetes was associated with reductions in blood pressure and triglycerides, over and above the effects of cardio-protective medication. Our findings support the notion that dietary change should be viewed as an integral component of successful diabetes self-management, irrespective of medication use.

Comparison of speech intelligibility in cockpit noise using SPH-4 flight helmet with and without active noise reduction

NASA Technical Reports Server (NTRS)

Chan, Jeffrey W.; Simpson, Carol A.

1990-01-01

Active Noise Reduction (ANR) is a new technology which can reduce the level of aircraft cockpit noise that reaches the pilot's ear while simultaneously improving the signal to noise ratio for voice communications and other information bearing sound signals in the cockpit. A miniature, ear-cup mounted ANR system was tested to determine whether speech intelligibility is better for helicopter pilots using ANR compared to a control condition of ANR turned off. Two signal to noise ratios (S/N), representative of actual cockpit conditions, were used for the ratio of the speech to cockpit noise sound pressure levels. Speech intelligibility was significantly better with ANR compared to no ANR for both S/N conditions. Variability of speech intelligibility among pilots was also significantly less with ANR. When the stock helmet was used with ANR turned off, the average PB Word speech intelligibility score was below the Normally Acceptable level. In comparison, it was above that level with ANR on in both S/N levels.

The role of a small posterior malleolar fragment in trimalleolar fractures: a biomechanical study.

PubMed

Evers, J; Fischer, M; Zderic, I; Wähnert, D; Richards, R G; Gueorguiev, B; Raschke, M J; Ochman, S

2018-01-01

The aim of this study was to investigate the effect of a posterior malleolar fragment (PMF), with < 25% ankle joint surface, on pressure distribution and joint-stability. There is still little scientific evidence available to advise on the size of PMF, which is essential to provide treatment. To date, studies show inconsistent results and recommendations for surgical treatment date from 1940. A total of 12 cadaveric ankles were assigned to two study groups. A trimalleolar fracture was created, followed by open reduction and internal fixation. PMF was fixed in Group I, but not in Group II. Intra-articular pressure was measured and cyclic loading was performed. Contact area decreased following each fracture, while anatomical fixation restored it nearly to its intact level. Contact pressure decreased significantly with fixation of the PMF. In plantarflexion, the centre of force shifted significantly posteriorly in Group II and anteriorly in Group I. Load to failure testing showed no difference between the groups. Surgical reduction of a small PMF with less than 25% ankle joint surface improves pressure distribution but does not affect ankle joint stability. Cite this article: Bone Joint J 2018;100-B:95-100. ©2018 The British Editorial Society of Bone & Joint Surgery.

High-pressure processing and antimicrobial biodegradable packaging to control Listeria monocytogenes during storage of cooked ham.

PubMed

Marcos, Begonya; Aymerich, Teresa; Monfort, Josep M; Garriga, Margarita

2008-02-01

The efficiency of combining high-pressure processing (HPP) and active packaging technologies to control Listeria monocytogenes growth during the shelf life of artificially inoculated cooked ham was assessed. Three lots of cooked ham were prepared: control, packaging with alginate films, and packaging with antimicrobial alginate films containing enterocins. After packaging, half of the samples were pressurized. Sliced cooked ham stored at 6 degrees C experienced a quick growth of L. monocytogenes. Both antimicrobial packaging and pressurization delayed the growth of the pathogen. However, at 6 degrees C the combination of antimicrobial packaging and HPP was necessary to achieve a reduction of inoculated levels without recovery during 60 days of storage. Further storage at 6 degrees C of pressurized antimicrobial packed cooked ham resulted in L. monocytogenes levels below the detection limit (day 90). On the other hand, storage at 1 degrees C controlled the growth of the pathogen until day 39 in non-pressurized ham, while antimicrobial packaging and storage at 1 degrees C exerted a bacteriostatic effect for 60 days. All HPP lots stored at 1 degrees C led to counts <100CFU/g at day 60. Similar results were observed when combining both technologies. After a cold chain break no growth of L. monocytogenes was observed in pressurized ham packed with antimicrobial films, showing the efficiency of combining both technologies.

Occupational leg oedema is more reduced by antigraduated than by graduated stockings.

PubMed

Mosti, G; Partsch, H

2013-05-01

Elastic compression stockings exerting a progressive pressure, higher at the calf than at the ankle (progressive elastic compression stockings, PECS), have already proved to be more comfortable, easier to put on and more effective in improving venous pumping function compared to graduated compression elastic stockings (GECS). Nevertheless, PECS could have a negative effect on the prevention and treatment of oedema or even favour oedema formation. The aim of the present study was to investigate if, in normal volunteers, PECS are able to prevent leg swelling during their working shift. A total of 30 normal volunteers (14 males, 16 females aged 36.4 ± 6.6 years) staying standing or sitting during their shift were enrolled into the study. Their leg volume was measured at the beginning and at the end of their working shift on 2 consecutive days. On one day, the volunteers did not put on any stockings; on the other day, they wore GECS on one leg and PECS on the other. The difference between the leg volume measured at the end of the shift and the basal volume in the morning was called 'occupational oedema'. Interface pressure at points B1 and C was measured immediately after stockings' application and before removal. The volunteers were asked to report about difficulty of putting on the stockings and comfort during wearing time. The results were submitted to statistical analysis. The GECS and PECS groups had similar baseline leg volumes (3143 vs. 3154 ml) and occupational oedema (134 vs. 137.5 ml); after putting on the stockings, occupational oedema was reduced in both legs but the reduction was significantly greater with PECS (20 vs. 40 ml with GECS) (P < 0.05). Interface pressure at ankle level is higher with GECS both in supine and in standing position while at calf level it is higher with PECS both in supine and standing position. PECS are easier to put on and slightly more comfortable. PECS are easier to put on and more comfortable and produce a significantly higher reduction of occupational oedema compared with GECS in normal volunteers. Nevertheless leg volumetry, providing a global leg-volume evaluation, is not able to localise the oedema reduction and to assess if it occurs more in the calf or the ankle area. Theoretically, despite a global volume reduction, PECS could even promote a slight oedema formation at ankle level over-compensated by a greater oedema reduction at calf level. Further studies need to concentrate on patients with venous disease and on the local distribution of this global effect. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Lower Sodium Intake and Risk of Headaches: Results From the Trial of Nonpharmacologic Interventions in the Elderly.

PubMed

Chen, Liwei; Zhang, Zhenzhen; Chen, Wen; Whelton, Paul K; Appel, Lawrence J

2016-07-01

To determine the effect of sodium (Na) reduction on occurrence of headaches. In the Trial of Nonpharmacologic Interventions in the Elderly, 975 men and woman (aged 60-80 years) with hypertension were randomized to a Na-reduction intervention or control group and were followed for up to 36 months. The study was conducted between 1992 and 1995 at 4 clinical centers (Johns Hopkins University, Wake Forest University School of Medicine, Robert Wood Johnson Medical School, and the University of Tennessee). Mean difference in Na excretion between the Na-reduction intervention and control group was significant at each follow-up visit (P < .001) with an average difference of 38.8 millimoles per 24 hours. The occurrence of headaches was significantly lower in the Na-reduction intervention group (10.5%) compared with control (14.3%) with a hazard ratio of 0.59 (95% confidence interval = 0.40, 0.88; P = .009). The risk of headaches was significantly associated with average level of Na excretion during follow-up, independent of most recent blood pressure. The relationship appeared to be nonlinear with a spline relationship and a knot at 150 millimoles per 24 hours. Reduced sodium intake, currently recommended for blood pressure control, may also reduce the occurrence of headaches in older persons with hypertension.

Magnesium sulphate attenuates arterial pressure increase during laparoscopic cholecystectomy.

PubMed

Jee, D; Lee, D; Yun, S; Lee, C

2009-10-01

Magnesium is well known to inhibit catecholamine release and attenuate vasopressin-stimulated vasoconstriction. We investigated whether i.v. magnesium sulphate attenuates the haemodynamic stress responses to pneumoperitoneum by changing neurohumoral responses during laparoscopic cholecystectomy. Thirty-two patients undergoing laparoscopic cholecystectomy were randomly assigned to two groups; a control group was given saline, and a magnesium group received magnesium sulphate 50 mg kg(-1) immediately before pneumoperitoneum. Arterial pressure, heart rate, serum magnesium, plasma renin activity (PRA), and catecholamine, cortisol, and vasopressin levels were measured. Systolic and diastolic arterial pressures were greater in the control group (P<0.05) than in the magnesium group at 10, 20, and 30 min post-pneumoperitoneum. Norepinephrine or epinephrine levels [pg ml(-1), mean (SD)] were higher in the control group than in the magnesium group at 5 [211 (37) vs 138 (18)] or 10 min [59 (19) vs 39 (9)] post-pneumoperitoneum, respectively (P<0.05). In the control group, vasopressin levels [pg ml(-1), mean (SD)] were higher compared with the magnesium group at 5 [64 (18) vs 35 (9), P<0.01] and 10 min [65 (18) vs 47 (11), P<0.05] post-pneumoperitoneum. There were no significant differences between the groups in PRA and cortisol levels. I.V. magnesium sulphate before pneumoperitoneum attenuates arterial pressure increases during laparoscopic cholecystectomy. This attenuation is apparently related to reductions in the release of catecholamine, vasopressin, or both.

Evaluation of Stress and a Stress-Reduction Program Among Radiologic Technologists.

PubMed

Reingold, Lynn

2015-01-01

To investigate stress levels and causes of stress among radiologic technologists and determine whether an intervention could reduce stress in a selected radiologic technologist population. Demographic characteristics and data on preintervention stress sources and levels were collected through Internet-based questionnaires. A 6-week, self-administered, mindfulness-based stress-reduction program was conducted as a pilot intervention with 42 radiologic technologists from the Veterans Administration Medical Center. Data also were collected postintervention. Identified sources of stress were compared with findings from previous studies. Some radiologic technologists experienced improvement in their perceptions of stress after the intervention. Sources of stress for radiologic technologists were similar to those shown in earlier research, including inconsistent management, poor management communication, conflicting demands, long work hours, excessive workloads, lack of work breaks, and time pressures. The mindfulness-based stress-reduction program is an example of an inexpensive method that could improve personal well-being, reduce work errors, improve relationships in the workplace, and increase job satisfaction. More research is needed to determine the best type of intervention for stress reduction in a larger radiologic technologist population.

Quiet Clean Short-haul Experimental Engine (QCSEE) clean combustor test report

NASA Technical Reports Server (NTRS)

1975-01-01

A component pressure test was conducted on a F101 PFRT combustor to evaluate the emissions levels of this combustor design at selected under the wing and over the wing operating conditions for the quiet clean short haul experimental engine (QCSEE). Emissions reduction techniques were evaluated which included compressor discharge bleed and sector burning in the combustor. The results of this test were utilized to compare the expected QCSEE emissions levels with the emission goals of the QCSEE engine program.

Projected Impact of a Sodium Consumption Reduction Initiative in Argentina: An Analysis from the CVD Policy Model – Argentina

PubMed Central

Konfino, Jonatan; Mekonnen, Tekeshe A.; Coxson, Pamela G.; Ferrante, Daniel; Bibbins-Domingo, Kirsten

2013-01-01

Background Cardiovascular disease (CVD) is the leading cause of death in adults in Argentina. Sodium reduction policies targeting processed foods were implemented in 2011 in Argentina, but the impact has not been evaluated. The aims of this study are to use Argentina-specific data on sodium excretion and project the impact of Argentina’s sodium reduction policies under two scenarios - the 2-year intervention currently being undertaken or a more persistent 10 year sodium reduction strategy. Methods We used Argentina-specific data on sodium excretion by sex and projected the impact of the current strategy on sodium consumption and blood pressure decrease. We assessed the projected impact of sodium reduction policies on CVD using the Cardiovascular Disease (CVD) Policy Model, adapted to Argentina, modeling two alternative policy scenarios over the next decade. Results Our study finds that the initiative to reduce sodium consumption currently in place in Argentina will have substantial impact on CVD over the next 10 years. Under the current proposed policy of 2-year sodium reduction, the mean sodium consumption is projected to decrease by 319–387 mg/day. This decrease is expected to translate into an absolute reduction of systolic blood pressure from 0.93 mmHg to 1.81 mmHg. This would avert about 19,000 all-cause mortality, 13,000 total myocardial infarctions, and 10,000 total strokes over the next decade. A more persistent sodium reduction strategy would yield even greater CVD benefits. Conclusion The impact of the Argentinean initiative would be effective in substantially reducing mortality and morbidity from CVD. This paper provides evidence-based support to continue implementing strategies to reduce sodium consumption at a population level. PMID:24040085

Decreasing the Hydroxylation Affinity of La 1–x Sr x MnO 3 Perovskites To Promote Oxygen Reduction Electrocatalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoerzinger, Kelsey A.; Hong, Wesley T.; Wang, Xiao Renshaw

Understanding the interaction between oxides and water is critical to design many of their functionalities, including the electrocatalysis of molecular oxygen reduction. In this study, we probed the hydroxylation of model (001)-oriented La(1-x)SrxMnO3 (LSMO) perovskite surfaces, where the electronic structure and manganese valence was controlled by five substitution levels of lanthanum with strontium, using ambient pressure X-ray photoelectron spectroscopy in a humid environment. The degree of hydroxyl formation on the oxide surface correlated with the proximity of the valence band center relative to the Fermi level. LSMO perovskites with a valence band center closer to the Fermi level were moremore » reactive toward water, forming more hydroxyl species at a given relative humidity. More hydroxyl species correlate with greater electron-donating character to the surface free energy in wetting, and reduce the activity to catalyze oxygen reduction reaction (ORR) kinetics in basic solution. New strategies to design more active catalysts should include design of electronically conducting oxides with lower valence band centers relative to the Fermi level at ORR-relevant potentials.« less

Apparatus and method to inject a reductant into an exhaust gas feedstream

DOEpatents

Viola, Michael B [Macomb Township, MI

2009-09-22

An exhaust aftertreatment system for an internal combustion engine is provided including an apparatus and method to inject a reductant into the exhaust gas feedstream. Included is a fuel metering device adapted to inject reductant into the exhaust gas feedstream and a controllable pressure regulating device. A control module is operatively connected to the reductant metering device and the controllable pressure regulating device, and, adapted to effect flow of reductant into the exhaust gas feedstream over a controllable flow range.

Optimization of Sound Absorbers Number and Placement in an Enclosed Room by Finite Element Simulation

NASA Astrophysics Data System (ADS)

Lau, S. F.; Zainulabidin, M. H.; Yahya, M. N.; Zaman, I.; Azmir, N. A.; Madlan, M. A.; Ismon, M.; Kasron, M. Z.; Ismail, A. E.

2017-10-01

Giving a room proper acoustic treatment is both art and science. Acoustic design brings comfort in the built environment and reduces noise level by using sound absorbers. There is a need to give a room acoustic treatment by installing absorbers in order to decrease the reverberant sound. However, they are usually high in price which cost much for installation and there is no system to locate the optimum number and placement of sound absorbers. It would be a waste if the room is overly treated with absorbers or cause improper treatment if the room is treated with insufficient absorbers. This study aims to determine the amount of sound absorbers needed and optimum location of sound absorbers placement in order to reduce the overall sound pressure level in specified room by using ANSYS APDL software. The size of sound absorbers needed is found to be 11 m 2 by using Sabine equation and different unit sets of absorbers are applied on walls, each with the same total areas to investigate the best configurations. All three sets (single absorber, 11 absorbers and 44 absorbers) has successfully treating the room by reducing the overall sound pressure level. The greatest reduction in overall sound pressure level is that of 44 absorbers evenly distributed around the walls, which has reduced as much as 24.2 dB and the least effective configuration is single absorber whereby it has reduced the overall sound pressure level by 18.4 dB.

Pollution measurements of a swirl-can combustor

NASA Technical Reports Server (NTRS)

Niedzwiecki, R. W.; Jones, R. E.

1972-01-01

Pollutant levels of oxides of nitrogen, unburned hydrocarbons, and carbon monoxide were measured for an experimental, annular, swirl can combustor. The combustor was 42 inches in diameter, incorporated 120 modules, and was specifically designed for elevated exit temperature performance. Test conditions included combustor inlet temperatures of 600, 900 and 1050 F, inlet pressures of 5 to 6 atmospheres, reference velocities of 69 to 120 feet per second and fuel-air ratios of 0.014 to 0.0695. Tests were also conducted at a simulated engine idle condition. Results demonstrated that swirl can combustors produce oxides of nitrogen levels substantially lower than conventional combustor designs. These reductions are attributed to reduced dwell times resulting from short combustor length, quick mixing of combustion gases with diluent air, and to uniform fuel distributions resulting from the swirl can approach. Radial staging of fuel at idle conditions resulted in increases in combustion efficiencies and corresponding reductions in pollutant levels.

Calculated effects of turbine rotor-blade cooling-air flow, altitude, and compressor bleed point on performance of a turbojet engine

NASA Technical Reports Server (NTRS)

Arne, Vernon L; Nachtigall, Alfred J

1951-01-01

Effects of air-cooling turbine rotor blades on performance of a turbojet engine were calculated for a range of altitudes from sea level to 40,000 feet and a range of coolant flows up to 3 percent of compressor air flow, for two conditions of coolant bleed from the compressor. Bleeding at required coolant pressure resulted in a sea-level thrust reduction approximately twice the percentage coolant flow and in an increase in specific fuel consumption approximately equal to percentage coolant flow. For any fixed value of coolant flow ratio the percentage thrust reduction and percentage increase in specific fuel consumption decreased with altitude. Bleeding coolant at the compressor discharge resulted in an additional 1 percent loss in performance at sea level and in smaller increase in loss of performance at higher altitudes.

Noise reduction tests of large-scale-model externally blown flap using trailing-edge blowing and partial flap slot covering. [jet aircraft noise reduction

NASA Technical Reports Server (NTRS)

Mckinzie, D. J., Jr.; Burns, R. J.; Wagner, J. M.

1976-01-01

Noise data were obtained with a large-scale cold-flow model of a two-flap, under-the-wing, externally blown flap proposed for use on future STOL aircraft. The noise suppression effectiveness of locating a slot conical nozzle at the trailing edge of the second flap and of applying partial covers to the slots between the wing and flaps was evaluated. Overall-sound-pressure-level reductions of 5 db occurred below the wing in the flyover plane. Existing models of several noise sources were applied to the test results. The resulting analytical relation compares favorably with the test data. The noise source mechanisms were analyzed and are discussed.

Pressure garment design tool to monitor exerted pressures.

PubMed

Macintyre, Lisa; Ferguson, Rhona

2013-09-01

Pressure garments are used in the treatment of hypertrophic scarring following serious burns. The use of pressure garments is believed to hasten the maturation process, reduce pruritus associated with immature hypertrophic scars and prevent the formation of contractures over flexor joints. Pressure garments are normally made to measure for individual patients from elastic fabrics and are worn continuously for up to 2 years or until scar maturation. There are 2 methods of constructing pressure garments. The most common method, called the Reduction Factor method, involves reducing the patient's circumferential measurements by a certain percentage. The second method uses the Laplace Law to calculate the dimensions of pressure garments based on the circumferential measurements of the patient and the tension profile of the fabric. The Laplace Law method is complicated to utilise manually and no design tool is currently available to aid this process. This paper presents the development and suggested use of 2 new pressure garment design tools that will aid pressure garment design using the Reduction Factor and Laplace Law methods. Both tools calculate the pressure garment dimensions and the mean pressure that will be exerted around the body at each measurement point. Monitoring the pressures exerted by pressure garments and noting the clinical outcome would enable clinicians to build an understanding of the implications of particular pressures on scar outcome, maturation times and patient compliance rates. Once the optimum pressure for particular treatments is known, the Laplace Law method described in this paper can be used to deliver those average pressures to all patients. This paper also presents the results of a small scale audit of measurements taken for the fabrication of pressure garments in two UK hospitals. This audit highlights the wide range of pressures that are exerted using the Reduction Factor method and that manual pattern 'smoothing' can dramatically change the actual Reduction Factors used. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Scattering of turbulent-jet wavepackets by a swept trailing edge.

PubMed

Piantanida, Selene; Jaunet, Vincent; Huber, Jérôme; Wolf, William R; Jordan, Peter; Cavalieri, André V G

2016-12-01

Installed jet noise is studied by means of a simplified configuration comprising a flat plate in the vicinity of a round jet. The effects of Mach number, jet-plate radial distance, and trailing-edge sweep angle are explored. Acoustic measurements are performed using a traversable 18-microphone azimuthal array, providing pressure data at 360 points on a cylindrical surface surrounding the jet-plate system. Key observations include a decrease, with increasing Mach number, of the relative level of the scattered field in comparison to the uninstalled jet; an exponential dependence of the scattered sound pressure level on the radial jet-plate separation; and considerable sideline noise reductions with increasing sweep angle, with which there is an overall reduction in acoustic efficiency. The measurements are compared with results obtained using a kinematic wavepacket source model, whose radiation is computed in two ways. A TGF for a semi-infinite flat plate is used to provide a low-order approximation of the scattering effect. Use of a more computationally intensive boundary element method provides additional precision. Good agreement between model predictions and experiment, encouraging from the perspective of low-cost prediction strategies, demonstrates that the models comprise the essential sound generation mechanisms.

Shaping and timing gradient pulses to reduce MRI acoustic noise.

PubMed

Segbers, Marcel; Rizzo Sierra, Carlos V; Duifhuis, Hendrikus; Hoogduin, Johannes M

2010-08-01

A method to reduce the acoustic noise generated by gradient systems in MRI has been recently proposed; such a method is based on the linear response theory. Since the physical cause of MRI acoustic noise is the time derivative of the gradient current, a common trapezoid current shape produces an acoustic gradient coil response mainly during the rising and falling edge. In the falling edge, the coil acoustic response presents a 180 degrees phase difference compared to the rising edge. Therefore, by varying the width of the trapezoid and keeping the ramps constant, it is possible to suppress one selected frequency and its higher harmonics. This value is matched to one of the prominent resonance frequencies of the gradient coil system. The idea of cancelling a single frequency is extended to a second frequency, using two successive trapezoid-shaped pulses presented at a selected interval. Overall sound pressure level reduction of 6 and 10 dB is found for the two trapezoid shapes and a single pulse shape, respectively. The acoustically optimized pulse shape proposed is additionally tested in a simulated echo planar imaging readout train, obtaining a sound pressure level reduction of 12 dB for the best case.

Blood pressure reduction by reducing sodium intake in the population: one shoe fits all?

PubMed

Teo, Koon; Mente, Andrew

2014-07-01

Current guidelines, based on extrapolations of observational studies or short-term relatively small clinical trials, recommend that daily sodium intake should be around 2 g/day or less. The assumption is that the relationship between sodium consumption and blood pressure (BP) levels is linear in all populations. Recent development suggests this may not be correct. We reviewed the literature on the association between sodium reduction and BP lowering, and preliminary data on 100,000 individuals from the Prospective Urban Rural Epidemiology study on sodium excretion and the association of sodium excretion with BP in general populations from 17 countries in five continents, with a focus on major subgroups. Earlier observational studies have shown inconsistencies in their findings which were not addressed by the recommendations. The PURE results showed that associations between sodium intake and BP were not linear; proportionally, higher BP was found in individuals with higher sodium intake compared with those with lower sodium intake, in individuals with hypertension compared to those without hypertension, and in older individuals compared with younger individuals. Recent data do not support the recommendation that all populations should reduce their sodium intake to one low level.

MEMS tandem ion-sorption micropump

NASA Astrophysics Data System (ADS)

Grzebyk, T.

2017-12-01

This paper presents a two-stage MEMS ion-sorption micropump, which works in a wide range of pressures—it allows efficient evacuation of gases from the internal volume of any microsystem starting from atmospheric pressure down to 10-6 hPa. The miniature pre-vacuum pump is realized as a two-electrode silicon-glass structure with a very close inter-electrode distance. The use of the silicon substrate as a getter material instead of a metallic layer significantly increases the pumping capacity and as a result, the initial pressure can be reduced to a level of 1 hPa. From this point the pumping is continued with the second glow-discharge high vacuum micropump. This pump is a multilayer structure, in which ions are trapped in crossed electric and magnetic fields. It allows further reduction of pressure down to 10-6 hPa. Both pumps are technologically compatible and together they enable the on-chip generation of avacuum at the desired level in a variety of miniaturized devices.

Spaceflight alters autonomic regulation of arterial pressure in humans

NASA Technical Reports Server (NTRS)

Fritsch-Yelle, Janice M.; Charles, John B.; Jones, Michele M.; Beightol, Larry A.; Eckberg, Dwain L.

1994-01-01

Spaceflight is associated with decreased orthostatic tolerance after landing. Short-duration spaceflight (4 - 5 days) impairs one neutral mechanism: the carotid baroreceptor-cardiac reflex. To understand the effects of longer-duration spaceflight on baroreflex function, we measured R-R interval power spectra, antecubital vein plasma catecholamine levels, carotid baroreceptor-cardiac reflex responses, responses to Valsalva maneuvers, and orthostatic tolerance in 16 astronauts before and after shuttle missions lasting 8 - 14 days. We found the following changes between preflight and landing day: (1) orthostatic tolerance decreased; (2) R-R interval spectral power in the 0.05- to 0.15-Hz band increased; (3) plasma norepinephrine and epinephrine levels increased; (4) the slope, range, and operational point of the carotid baroreceptor cardiac reflex response decreased; and (5) blood pressure and heart rate responses to Valsalva maneuvers were altered. Autonomic changes persisted for several days after landing. These results provide further evidence of functionally relevent reductions in parasympathetic and increases in sympathetic influences on arterial pressure control after spaceflight.

Redox Signaling via Oxidative Inactivation of PTEN Modulates Pressure-Dependent Myogenic Tone in Rat Middle Cerebral Arteries

PubMed Central

Gebremedhin, Debebe; Terashvili, Maia; Wickramasekera, Nadi; Zhang, David X.; Rau, Nicole; Miura, Hiroto; Harder, David R.

2013-01-01

The present study examined the level of generation of reactive oxygen species (ROS) and roles of inactivation of the phosphatase PTEN and the PI3K/Akt signaling pathway in response to an increase in intramural pressure-induced myogenic cerebral arterial constriction. Step increases in intraluminal pressure of cannulated cerebral arteries induced myogenic constriction and concomitant formation of superoxide (O2 .−) and its dismutation product hydrogen peroxide (H2O2) as determined by fluorescent HPLC analysis, microscopic analysis of intensity of dihydroethidium fluorescence and attenuation of pressure-induced myogenic constriction by pretreatment with the ROS scavenger 4,hydroxyl-2,2,6,6-tetramethylpiperidine1-oxyl (tempol) or Mito-tempol or MitoQ in the presence or absence of PEG-catalase. An increase in intraluminal pressure induced oxidation of PTEN and activation of Akt. Pharmacological inhibition of endogenous PTEN activity potentiated pressure-dependent myogenic constriction and caused a reduction in NPo of a 238 pS arterial KCa channel current and an increase in [Ca2+]i level in freshly isolated cerebral arterial muscle cells (CAMCs), responses that were attenuated by Inhibition of the PI3K/Akt pathway. These findings demonstrate an increase in intraluminal pressure induced increase in ROS production triggered redox-sensitive signaling mechanism emanating from the cross-talk between oxidative inactivation of PTEN and activation of the PI3K/Akt signaling pathway that involves in the regulation of pressure-dependent myogenic cerebral arterial constriction. PMID:23861911

Redox signaling via oxidative inactivation of PTEN modulates pressure-dependent myogenic tone in rat middle cerebral arteries.

PubMed

Gebremedhin, Debebe; Terashvili, Maia; Wickramasekera, Nadi; Zhang, David X; Rau, Nicole; Miura, Hiroto; Harder, David R

2013-01-01

The present study examined the level of generation of reactive oxygen species (ROS) and roles of inactivation of the phosphatase PTEN and the PI3K/Akt signaling pathway in response to an increase in intramural pressure-induced myogenic cerebral arterial constriction. Step increases in intraluminal pressure of cannulated cerebral arteries induced myogenic constriction and concomitant formation of superoxide (O2 (.-)) and its dismutation product hydrogen peroxide (H2O2) as determined by fluorescent HPLC analysis, microscopic analysis of intensity of dihydroethidium fluorescence and attenuation of pressure-induced myogenic constriction by pretreatment with the ROS scavenger 4,hydroxyl-2,2,6,6-tetramethylpiperidine1-oxyl (tempol) or Mito-tempol or MitoQ in the presence or absence of PEG-catalase. An increase in intraluminal pressure induced oxidation of PTEN and activation of Akt. Pharmacological inhibition of endogenous PTEN activity potentiated pressure-dependent myogenic constriction and caused a reduction in NPo of a 238 pS arterial KCa channel current and an increase in [Ca(2+)]i level in freshly isolated cerebral arterial muscle cells (CAMCs), responses that were attenuated by Inhibition of the PI3K/Akt pathway. These findings demonstrate an increase in intraluminal pressure induced increase in ROS production triggered redox-sensitive signaling mechanism emanating from the cross-talk between oxidative inactivation of PTEN and activation of the PI3K/Akt signaling pathway that involves in the regulation of pressure-dependent myogenic cerebral arterial constriction.

Nickel-Hydrogen Batteries - An Overview

NASA Technical Reports Server (NTRS)

Smithrick, John J.; ODonnell, Patricia M.

1996-01-01

This article on nickel-hydrogen batteries is an overview of the various nickel-hydrogen battery design options, technical accomplishments, validation test results, and trends. There is more than one nickel-hydrogen battery design, each having its advantage for specific applications. The major battery designs are Individual Pressure Vessel (IPV), Common Pressure Vessel (CPV), bipolar, and low-pressure metal hydride. State-of-the-art nickel-hydrogen batteries are replacing nickel-cadmium batteries in almost all geosynchronous Earth orbit applications requiring power above 1 kW. However, for the more severe Low-Earth Orbit (LEO) applications (greater than 30,000 cycles), the current cycle life of 4000-10,000 cycles at 60 - 80 % DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel-hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep Depths of Discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low-cost satellites. Hence, the challenge is to reduce battery mass, volume, and cost. A key is to develop a lightweight nickel electrode and alternate battery designs. A CPV nickel-hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume, and manufacturing costs. A 10-A-h CPV battery has successfully provided power on the relatively short-lived Clementine spacecraft. A bipolar nickel -hydrogen battery design has been demonstrated (15,000 LEO cycles, 40 % DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high-pulse power capability. A low-pressure aerospace nickel-metal-hydride battery cell has been developed and is on the market. It is a prismatic design that has the advantage of a significant reduction in volume and a reduction in manufacturing cost.

[Evaluation of antihypertensive therapy by ambulatory blood pressure monitoring and establishment of the level of antihypertensive goal on the circadian rhythm of blood pressure].

PubMed

Fujioka, T; Tamaki, S; Fudo, T; Nakae, I; Sugawara, A; Kambara, H

1990-01-01

We have developed a new method for the evaluation of antihypertensive therapy on the circadian rhythm of blood pressure and attempted to determine the indications for antihypertensive therapy and the level of antihypertensive goal. Blood pressures were measured for 24 hours by the use of ambulatory blood pressure monitoring using 630 (ABPM-630) in 50 normotensives, 50 untreated hypertensives and 50 hypertensives undertreatment with various antihypertensive drugs (110 males and 40 females, with a mean age of 53.4 +/- 13.3 yrs). Blood pressure profiles were prepared for determination of the hyperbaric and hypobaric indexes. According to the WHO's definitions for blood pressure, the hyperbaric index was defined as the area above 140 mmHg in systolic blood pressure or 90 mmHg in diastolic blood pressure, and the hypobaric index, as the area below 100 mmHg or 60 mmHg, respectively. The criteria of the hypobaric index was obtained from the mean basal blood pressure (the lowest blood pressure during sleep) of the 50 normotensives. The mean hyperbaric index of the 50 normotensives was 20.4 +/- 40.2/5.5 +/- 15.3 (systole/diastole) mmHg.hour/day and the mean hypobaric index, 12.2 +/- 22.5/9.0 +/- 24.0 mmHg.hour/day. The 50 untreated hypertensives showed a mean hyperbaric index of 281.8 +/- 197.0/156.0 +/- 126.1 mmHg.hour/day and a mean hypobaric index of 0.1 +/- 0.6/0.3 +/- 1.5 mmHg.hour/day. Comparison of the indexes before and after treatment with various antihypertensives showed that a decrease in the hyperbaric index without an increase in the hypobaric index was the most optimal reduction of blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

[The predictive value of dynamic arterial elastance in arterial pressure response after norepinephrine dosage reduction in patients with septic shock].

PubMed

Liang, F M; Yang, T; Dong, L; Hui, J J; Yan, J

2017-05-01

Objective: To assess whether dynamic arterial elastance(Ea(dyn))can be used to predict the reduction of arterial pressure after decreasing norepinephrine (NE) dosage in patients with septic shock. Methods: A prospective observational cohort study was conducted. Thirty-two patients with septic shock and mechanical ventilationwere enrolledfrom January 2014 to December 2015 in ICU of Wuxi People's Hospital of Nanjing Medical University. Hemodynamic parameters were recorded by pulse contour cardiac output(PiCCO)monitoring technology before and after decreasing norepinephrine dosage. Ea(dyn) was defined as the ratio of pulse pressure variation (PPV) to stroke volume variation (SVV). Mean arterial pressure(MAP) variation was calculated after decreasing the dose of NE. Response was defined as a ≥15% decrease of MAP. AUC was plotted to assess the value of Ea(dyn) in predicting MAP response. Results: A total of 32 patients were enrolled in our study, with 13 responding to NE dose decrease where as the other 19 did not. Ea(dyn) was lower in responders than in nonresponders (0.77±0.13 vs 1.09±0.31, P <0.05). Baseline Ea(dyn) was positively correlated with systolic blood pressure variation, diastolic blood pressure variation, systemic vascular resistance variation and MAP variation( r =0.621, P =0.000; r =0.735, P =0.000; r =0.756, P =0.000; r =0.568, P =0.000 respectively). However, stoke volume variation, baseline level of systemic vascular resistance and NE baseline dose were not correlated with Ea(dyn) baseline value( r =0.264, P =0.076; r =0.078, P =0.545; r =0.002, P =0.987 respectively). Ea(dyn)≤0.97 predicted a decrease of MAP when decreasing NE dose, with an area under the receiver-operating characteristic curve of 0.85.The sensitivity was 100.0% and specificity was 73.7%. Conclusions: In septic shock patients treated with NE, Ea(dyn) is an index to predict the decrease of arterial pressure in response to NE dose reduction.

Sodium-Glucose linked transporter 2 (SGLT2) inhibitors--fighting diabetes from a new perspective.

PubMed

Angelopoulos, Theodoros P; Doupis, John

2014-06-01

Sodium-Glucose linked transporter 2 (SGLT2) inhibitors are a new family of antidiabetic pharmaceutical agents whose action is based on the inhibition of the glucose reabsorption pathway, resulting in glucosuria and a consequent reduction of the blood glucose levels, in patients with type 2 diabetes mellitus. Apart from lowering both fasting and postprandial blood glucose levels, without causing hypoglycemia, SGLT2 inhibitors have also shown a reduction in body weight and the systolic blood pressure. This review paper explores the renal involvement in glucose homeostasis providing also the latest safety and efficacy data for the European Medicines Agency and U.S. Food and Drug Administration approved SGLT2 inhibitors, looking, finally, into the future of this novel antidiabetic category of pharmaceutical agents.

Effectiveness of perindopril/amlodipine fixed dose combination in everyday clinical practice: results from the EMERALD study.

PubMed

Vlachopoulos, C; Grammatikou, V; Kallistratos, M; Karagiannis, A

2016-09-01

The rates of blood pressure (BP) control worldwide are discouraging. This study had the purpose of assessing the effectiveness of perindopril/amlodipine fixed dose combination on BP-lowering efficacy, and recording adherence, safety and tolerability during a 4 month treatment period. In this multicenter, observational study 2269 hypertensive patients were prospectively enrolled. The data were recorded at 1 and 4 months of treatment. Between the first and third visits mean BP values (systolic/diastolic) decreased from 158.4 ± 13.6/89.9 ± 8.7 mmHg to 130.0 ± 7.9/77.7 ± 6.3 mmHg (P < 0.001). The magnitude of BP reduction depended on baseline blood pressure levels and total cardiovascular (CV) risk (P < 0.001). Patients with grade 1, 2 and 3 showed a BP reduction of 21.9/10.0 mmHg, 34.4/14.2 mmHg and 51.4/21.2 mmHg, accordingly (P < 0.001). Patients with very high, high, moderate and low added CV risk showed a BP reduction of 35.7/14.9 mmHg, 27.5/12.1 mmHg, 28.6/12.2 mmHg and 14.5/5.8 mmHg respectively (P < 0.001). Adherence to treatment was high: 98.3% of the sample was taking the treatment "every day" or "quite often", while only 15 patients (0.7% of the sample) prematurely discontinued treatment. Study interpretation may be limited by the fact that this is an observational study with no comparator and a short follow-up period. A perindopril/amlodipine fixed dose combination significantly decreases BP levels. The degree of BP reduction is related to baseline BP levels and total CV risk.

Role of triple fixed combination valsartan, amlodipine and hydrochlorothiazide in controlling blood pressure

PubMed Central

Doménech, Monica; Coca, Antonio

2010-01-01

Hypertension is one of the main risk factors for the development of cardiovascular diseases and the search for new therapeutic strategies aimed at optimizing its control remains an ongoing research and clinical challenge. In recent years, there has been a marked increase in the use of combinations of antihypertensive drugs with complementary mechanisms of action, with the aims of reducing blood pressure levels more rapidly and vigorously than strategies employing monotherapy and improving treatment compliance and adhesion. Therefore, as recommended by the 2009 reappraisal of the European Society of Hypertension/European Society of Cardiology Guidelines, the use of a triple combination that combines a calcium channel blocker, an angiotensin II receptor blocker and a thiazide diuretic seems a reasonable and efficacious combination for the management of hypertensive patients with moderate, high or very high risk. This article reviews the clinical trials carried out with the fixed combination of amlodipine/valsartan/hydrochlorothiazide at the doses recommended for each drug in monotherapy. The data show that this combination achieved greater reductions in mean sitting diastolic and systolic blood pressure than amlodipine, valsartan or hydrochlorothiazide in monotherapy, with favorable pharmacodynamic and pharmacokinetic profiles. The triple combination at high single doses should be used with caution in elderly patients and those with renal or liver failure. Although the tolerability and safety of the triple combination are good, the most-frequently reported adverse effects were peripheral edema, headache and dizziness. Analytical alterations were consistent with the already-known biochemical effects of amlodipine, valsartan or hydrochlorothiazide in monotherapy. In summary, triple-therapy with amlodipine/valsartan/hydrochlorothiazide in a single pill contributes additional advantages to fixed -combinations of two drugs, achieving a greater and more rapid reduction in blood pressure levels in a safe, well-tolerated manner. PMID:20517471

Evaluating the effectiveness of induced seismicity mitigation: Numerical modeling of wastewater injection near Greeley, Colorado

NASA Astrophysics Data System (ADS)

Brown, Megan R. M.; Ge, Shemin; Sheehan, Anne F.; Nakai, Jenny S.

2017-08-01

Mitigation of injection-induced seismicity in Greeley, Colorado, is based largely on proximity of wastewater disposal wells to seismicity and consists of cementation of the bottom of wells to eliminate connection between the disposal interval and crystalline basement. Brief injection rate reductions followed felt events, but injection rates returned to high levels, >250,000 barrels/month, within 6 months. While brief rate reduction reduces seismicity in the short term, overall seismicity is not reduced. We examine contributions to pore pressure change by injection from 22 wells within 30 km of the center of seismicity. The combined injection rate of seven disposal wells within 15 km of the seismicity (Greeley Wells) is correlated with the seismicity rate. We find that injection from NGL-C4A, the well previously suspected as the likely cause of the induced seismicity, is responsible for 28% of pore pressure increase. The other six Greeley Wells contribute 28% of pore pressure increase, and the 15 Far-field Wells between 15 and 30 km from the seismicity contribute 44% of pore pressure increase. Modeling results show that NGL-C4A plays the largest role in increased pore pressure but shows that the six other Greeley Wells have approximately the same influence as NGL-C4A. Furthermore, the 15 Far-field Wells have significant influence on pore pressure near the seismicity. Since the main mitigation action of cementing the bottom of wells has not decreased seismicity, mitigation based on reduced injection rates and spacing wells farther apart would likely have a higher potential for success.

Effects of Lifestyle Modification on Telomerase Gene Expression in Hypertensive Patients: A Pilot Trial of Stress Reduction and Health Education Programs in African Americans.

PubMed

Duraimani, Shanthi; Schneider, Robert H; Randall, Otelio S; Nidich, Sanford I; Xu, Shichen; Ketete, Muluemebet; Rainforth, Maxwell A; Gaylord-King, Carolyn; Salerno, John W; Fagan, John

2015-01-01

African Americans suffer from disproportionately high rates of hypertension and cardiovascular disease. Psychosocial stress, lifestyle and telomere dysfunction contribute to the pathogenesis of hypertension and cardiovascular disease. This study evaluated effects of stress reduction and lifestyle modification on blood pressure, telomerase gene expression and lifestyle factors in African Americans. Forty-eight African American men and women with stage I hypertension who participated in a larger randomized controlled trial volunteered for this substudy. These subjects participated in either stress reduction with the Transcendental Meditation technique and a basic health education course (SR) or an extensive health education program (EHE) for 16 weeks. Primary outcomes were telomerase gene expression (hTERT and hTR) and clinic blood pressure. Secondary outcomes included lifestyle-related factors. Data were analyzed for within-group and between-group changes. Both groups showed increases in the two measures of telomerase gene expression, hTR mRNA levels (SR: p< 0.001; EHE: p< 0.001) and hTERT mRNA levels (SR: p = 0.055; EHE: p< 0.002). However, no statistically significant between-group changes were observed. Both groups showed reductions in systolic BP. Adjusted changes were SR = -5.7 mm Hg, p< 0.01; EHE = -9.0 mm Hg, p < 0.001 with no statistically significant difference between group difference. There was a significant reduction in diastolic BP in the EHE group (-5.3 mm Hg, p< 0.001) but not in SR (-1.2 mm Hg, p = 0.42); the between-group difference was significant (p = 0.04). The EHE group showed a greater number of changes in lifestyle behaviors. In this pilot trial, both stress reduction (Transcendental Meditation technique plus health education) and extensive health education groups demonstrated increased telomerase gene expression and reduced BP. The association between increased telomerase gene expression and reduced BP observed in this high-risk population suggest hypotheses that telomerase gene expression may either be a biomarker for reduced BP or a mechanism by which stress reduction and lifestyle modification reduces BP. ClinicalTrials.gov NCT00681200.

Effects of Lifestyle Modification on Telomerase Gene Expression in Hypertensive Patients: A Pilot Trial of Stress Reduction and Health Education Programs in African Americans

PubMed Central

Duraimani, Shanthi; Schneider, Robert H.; Randall, Otelio S.; Nidich, Sanford I.; Xu, Shichen; Ketete, Muluemebet; Rainforth, Maxwell A.; Gaylord-King, Carolyn; Salerno, John W.; Fagan, John

2015-01-01

Background African Americans suffer from disproportionately high rates of hypertension and cardiovascular disease. Psychosocial stress, lifestyle and telomere dysfunction contribute to the pathogenesis of hypertension and cardiovascular disease. This study evaluated effects of stress reduction and lifestyle modification on blood pressure, telomerase gene expression and lifestyle factors in African Americans. Methods Forty-eight African American men and women with stage I hypertension who participated in a larger randomized controlled trial volunteered for this substudy. These subjects participated in either stress reduction with the Transcendental Meditation technique and a basic health education course (SR) or an extensive health education program (EHE) for 16 weeks. Primary outcomes were telomerase gene expression (hTERT and hTR) and clinic blood pressure. Secondary outcomes included lifestyle-related factors. Data were analyzed for within-group and between-group changes. Results Both groups showed increases in the two measures of telomerase gene expression, hTR mRNA levels (SR: p< 0.001; EHE: p< 0.001) and hTERT mRNA levels (SR: p = 0.055; EHE: p< 0.002). However, no statistically significant between-group changes were observed. Both groups showed reductions in systolic BP. Adjusted changes were SR = -5.7 mm Hg, p< 0.01; EHE = -9.0 mm Hg, p < 0.001 with no statistically significant difference between group difference. There was a significant reduction in diastolic BP in the EHE group (-5.3 mm Hg, p< 0.001) but not in SR (-1.2 mm Hg, p = 0.42); the between-group difference was significant (p = 0.04). The EHE group showed a greater number of changes in lifestyle behaviors. Conclusion In this pilot trial, both stress reduction (Transcendental Meditation technique plus health education) and extensive health education groups demonstrated increased telomerase gene expression and reduced BP. The association between increased telomerase gene expression and reduced BP observed in this high-risk population suggest hypotheses that telomerase gene expression may either be a biomarker for reduced BP or a mechanism by which stress reduction and lifestyle modification reduces BP. Trial Registration ClinicalTrials.gov NCT00681200 PMID:26571023

Reduction of Altitude Diffuser Jet Noise Using Water Injection

NASA Technical Reports Server (NTRS)

Allgood, Daniel C.; Saunders, Grady P.; Langford, Lester A.

2014-01-01

A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser.

Reduction of Altitude Diffuser Jet Noise Using Water Injection

NASA Technical Reports Server (NTRS)

Allgood, Daniel C.; Saunders, Grady P.; Langford, Lester A.

2011-01-01

A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser.

Optimal ventilatory patterns in periodic breathing.

PubMed

Ghazanshahi, S D; Khoo, M C

1993-01-01

The goal of this study was to determine whether periodic breathing (PB), which is highly prevalent during sleep at high altitudes, imposes physiological penalties on the respiratory system in the absence of any accompanying disease. Using a computer model of respiratory gas exchange, we compared the effects of a variety of PB patterns on the chemical and mechanical costs of breathing to those resulting from regular tidal breathing. Although PB produced considerable fluctuation in arterial blood gas tensions, for the same cycle-averaged ventilation, higher arterial oxygen saturation and lower arterial carbon dioxide levels were achieved. This result can be explained by the fact that the combination of large breaths and apnea in PB leads to a substantial reduction in dead space ventilation. At the same time, the savings in mechanical cost achieved by the respiratory muscles during apnea partially offset the increase during the breathing phase. Consequently, the "pressure cost," a criterion based on mean inspiratory pressure, was elevated only slightly, although the average work rate of breathing increased significantly. We found that, at extreme altitudes, PB patterns with clusters of 2 to 4 large breaths that alternate with apnea produce the highest arterial oxygenation levels and lowest pressure costs. The common occurrence of PB patterns with closely similar features has been reported in sleeping healthy sojourners at extreme altitudes. Taken together, these findings suggest that PB favors a reduction in the oxygen demands of the respiratory muscles and therefore may not be as detrimental as it is generally believed to be.

The influence of tumour necrosis factor-alpha on the cardiovascular system of anaesthetized rats.

PubMed

Tabrizchi, R

2001-03-01

The effects of two vasoactive agents (adenosine A2A agonist, CGS 21680, and adrenoceptor agonist, noradrenaline) were examined on cardiac output (CO), heart rate (HR), blood pressure (BP), mean circulatory filling pressure (Pmcf), resistance to venous return, arterial resistance, dP/dt, plasma levels of NO2-/NO3-, and inducible nitric oxide synthase (iNOS) activity in lungs ex vivo, following treatment with tumour necrosis factor-alpha (TNF-alpha; 30 microg/kg) in anaesthetized rats. Treatment with TNF-alpha produced significant reduction in CO (41+/-2%), dP/dt (26+/-3%), BP (26+/-2%) and Pmcf (27+/-4%; n=6; mean+/-SEM), but increased arterial resistance. There were no significant changes in the plasma levels of NO2-/NO3-levels over time following treatment with TNF-alpha, but there was a significant increase (approximately twofold) in the activity of the iNOS in the lungs of animals treated with TNF-alpha. Administration of CGS 21680 (1.0 microg/kg per min) significantly increased CO (44+/-6%), HR (12+/-2%), Pmcf (24+/-4%) and dP/dt (24+/-5%) in TNF-alpha-treated rats. CGS 21680 also significantly reduced arterial resistance (33+/-2%) without altering resistance to venous return in TNF-alpha-treated rats. While noradrenaline (1.0 microg/kg per min) infusion did not significantly increase CO, it did significantly increase HR (12+/-1%), BP (55+/-9%), Pmcf (47+/-5%), dP/dt (65+/-7%), resistance to venous return (64+/-20%), and arterial resistance (41+/-16%) in TNF-alpha-treated animals. The reduction in BP due to administration of TNF-alpha is the result of significant reduction in CO. Consequently, the decline in CO can be attributed to a combination of a negative inotropic effect as well as a reduction in Pmcf. It is evident that infusion with CGS 21680 could reverse the negative impact of TNF-alpha on CO by increasing dP/dt, Pmcf and HR as well as a reduction in arterial resistance. The fact that noradrenaline did not significantly increase CO in TNF-alpha-treated rats can be attributed to increased arterial resistance as well increase in resistance to venous return.

Reduction of mean arterial pressure and proteinuria by the effect of ACEIs (Lisinopril) in Kurdish hypertensive patients in Hawler City.

PubMed

Muslih, A I

2012-06-30

The angiotensin converting enzyme inhibitors (ACEIs) are a group of pharmaceuticals that are used primarily in treatment of hypertension and congestive heart failure, in some cases as the drugs of first choice. The renin-angiotensin system is activated in response to hypotension, decreased sodium concentration in the distal tubule, decreased blood volume and in renal sympathetic nerve stimulation. This study examines the effects of angiotensin converting enzyme inhibitor (Lisinopril) on blood pressure (BP) 131 ± 2.4 and proteinuria 0.198 ± 0.005 in Kurd hypertensive patients, mean arterial blood pressure and proteinuria excretion were measured weekly along the period of 12 weeks. Lisinopril significantly reduced mean arterial blood pressure, and attenuated proteinuria level in patients subjected to this study in lisinopril 10mg dose dependent manner (p<0.05, n=24). In conclusion, lisinopril is of beneficial of renoprotection and in lowering BP.

Pressure and temperature dependence of the Ce valence and c -f hybridization gap in Ce T2In5(T =Co ,Rh ,Ir ) heavy-fermion superconductors

NASA Astrophysics Data System (ADS)

Yamaoka, H.; Yamamoto, Y.; Schwier, E. F.; Honda, F.; Zekko, Y.; Ohta, Y.; Lin, J.-F.; Nakatake, M.; Iwasawa, H.; Arita, M.; Shimada, K.; Hiraoka, N.; Ishii, H.; Tsuei, K.-D.; Mizuki, J.

2015-12-01

Pressure- and temperature-induced changes in the Ce valence and c -f hybridization of the Ce115 superconductors have been studied systematically. Resonant x-ray-emission spectroscopy indicated that the increase of the Ce valence with pressure was significant for CeCoIn5, and moderate for CeIr (In0.925Cd0.075)5 . We found no abrupt change of the Ce valence in the Kondo regime for CeIr (In0.925Cd0.075)5 , which suggests that valence fluctuations are unlikely to mediate the superconductivity in this material. X-ray-diffraction results were consistent with the pressure-induced change in the Ce valence. High-resolution photoelectron spectroscopy revealed a temperature-dependent reduction of the spectral intensity at the Fermi level, indicating enhanced c -f hybridization on cooling.

Effect of metatarsal pad placement on plantar pressure in people with diabetes mellitus and peripheral neuropathy.

PubMed

Hastings, Mary K; Mueller, Michael J; Pilgram, Thomas K; Lott, Donovan J; Commean, Paul K; Johnson, Jeffrey E

2007-01-01

Standard prevention and treatment strategies to decrease peak plantar pressure include a total contact insert with a metatarsal pad, but no clear guidelines exist to determine optimal placement of the pad with respect to the metatarsal head. The purpose of this study was to determine the effect of metatarsal pad location on peak plantar pressure in subjects with diabetes mellitus and peripheral neuropathy. Twenty subjects with diabetes mellitus, peripheral neuropathy, and a history of forefoot plantar ulcers were studied (12 men and eight women, mean age=57+/-9 years). CT determined the position of the metatarsal pad relative to metatarsal head and peak plantar pressures were measured on subjects in three footwear conditions: extra-depth shoes and a 1) total contact insert, 2) total contact insert and a proximal metatarsal pad, and 3) total contact insert and a distal metatarsal pad. The change in peak plantar pressure between shoe conditions was plotted and compared to metatarsal pad position relative to the second metatarsal head. Compared to the total contact insert, all metatarsal pad placements between 6.1 mm to 10.6 mm proximal to the metatarsal head line resulted in a pressure reduction (average reduction=32+/-16%). Metatarsal pad placements between 1.8 mm distal and 6.1 mm proximal and between 10.6 mm proximal and 16.8 mm proximal to the metatarsal head line resulted in variable peak plantar pressure reduction (average reduction=16+/-21%). Peak plantar pressure increased when the metatarsal pad was located more than 1.8 mm distal to the metatarsal head line. Consistent peak plantar pressure reduction occurred when the metatarsal pad in this study was located between 6 to 11 mm proximal to the metatarsal head line. Pressure reduction lessened as the metatarsal pad moved outside of this range and actually increased if the pad was located too distal of this range. Computational models are needed to help predict optimal location of metatarsal pad with a variety of sizes, shapes, and material properties.

Peptide YY kinetics and effects on blood pressure and circulating pancreatic and gastrointestinal hormones and metabolites in man.

PubMed

Adrian, T E; Sagor, G R; Savage, A P; Bacarese-Hamilton, A J; Hall, G M; Bloom, S R

1986-10-01

Peptide YY (PYY) is a 36 amino acid peptide produced by mucosal endocrine cells of the ileum and colon which inhibits acid secretion and intestinal transit in man. To assess its effects on metabolites and digestive hormones PYY was infused into 18 fasting normal subjects at three dose levels (0.06, 0.19, and 0.57 pmol kg-1 min-1), each for a period of 1 h. During the infusions mean plasma PYY levels increased by 8, 25, and 73 pmol/liter, respectively. The mean disappearance half-time on stopping the infusions was 9.2 +/- 0.4 (SEM) min. The mean MCR was 7.3 +/- 0.7 ml kg-1 min-1 and the apparent volume of distribution was calculated to be 94 +/- 9 ml kg-1. During the highest dose infusion there was a significant increase in both systolic and diastolic blood pressure, of 8.6 +/- 3.7 mmHg (P less than 0.05) and 10.9 +/- 3.0 mmHg (P less than 0.01), respectively. PYY caused a significant 50% reduction in plasma pancreatic polypeptide concentrations (P less than 0.05) and a 55% reduction in circulating motilin levels (P less than 0.05). PYY had no significant effect on circulating concentrations of insulin, glucagon, gastrin, gastric inhibitory peptide, neurotensin, enteroglucagon, or vasoactive intestinal peptide. PYY also had no significant effect on circulating concentrations of glucose, lactate, glycerol, or nonesterified fatty acids. This recently discovered human intestinal hormonal peptide thus has significant effects both on gastrointestinal hormones (motilin and pancreatic polypeptide) and blood pressure in man, but appears not to influence glucose or lipid metabolism.

Bacteria permeabilization and disruption caused by sludge reduction technologies evaluated by flow cytometry.

PubMed

Foladori, P; Tamburini, S; Bruni, L

2010-09-01

Technologies proposed in the last decades for the reduction of the sludge production in wastewater treatment plants and based on the mechanism of cell lysis-cryptic growth (physical, mechanical, thermal, chemical, oxidative treatments) have been widely investigated at lab-, pilot- and, in some cases, at full-scale but the effects on cellular lysis have not always been demonstrated in depth. The research presented in this paper aims to investigate how these sludge reduction technologies affect the integrity and permeabilization of bacterial cells in sludge using flow cytometry (FCM), which permits the rapid and statistically accurate quantification of intact, permeabilised or disrupted bacteria in the sludge using a double fluorescent DNA-staining instead of using conventional methods like plate counts and microscope. Physical/mechanical treatments (ultrasonication and high pressure homogenisation) caused moderate effects on cell integrity and caused significant cell disruption only at high specific energy levels. Conversely, thermal treatment caused significant damage of bacterial membranes even at moderate temperatures (45-55 °C). Ozonation significantly affected cell integrity, even at low ozone dosages, below 10 mgO(3)/gTSS, causing an increase of permeabilised and disrupted cells. At higher ozone dosages the compounds solubilised after cell lysis act as scavengers in the competition between soluble compounds and (particulate) bacterial cells. An original aspect of this paper, not yet reported in the literature, is the comparison of the effects of these sludge reduction technologies on bacterial cell integrity and permeabilization by converting pressure, temperature and ozone dosage to an equivalent value of specific energy. Among these technologies, comparison of the applied specific energy demonstrates that achieving the complete disruption of bacterial cells is not always economically advantageous because excessive energy levels may be required. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effect of soya protein on blood pressure: a meta-analysis of randomised controlled trials.

PubMed

Dong, Jia-Yi; Tong, Xing; Wu, Zhi-Wei; Xun, Peng-Cheng; He, Ka; Qin, Li-Qiang

2011-08-01

Observational studies have indicated that soya food consumption is inversely associated with blood pressure (BP). Evidence from randomised controlled trials (RCT) on the BP-lowering effects of soya protein intake is inconclusive. We aimed to evaluate the effectiveness of soya protein intake in lowering BP. The PubMed database was searched for published RCT in the English language through to April 2010, which compared a soya protein diet with a control diet. We conducted a random-effects meta-analysis to examine the effects of soya protein on BP. Subgroup and meta-regression analyses were performed to explore possible explanations for heterogeneity among trials. Meta-analyses of twenty-seven RCT showed a mean decrease of 2·21 mmHg (95 % CI - 4·10, - 0·33; P = 0·021) for systolic BP (SBP) and 1·44 mmHg (95 % CI - 2·56, - 0·31; P = 0·012) for diastolic BP (DBP), comparing the participants in the soya protein group with those in the control group. Soya protein consumption significantly reduced SBP and DBP in both hypertensive and normotensive subjects, and the reductions were markedly greater in hypertensive subjects. Significant and greater BP reductions were also observed in trials using carbohydrate, but not milk products, as the control diet. Meta-regression analyses further revealed a significantly inverse association between pre-treatment BP and the level of BP reductions. In conclusion, soya protein intake, compared with a control diet, significantly reduces both SBP and DBP, but the BP reductions are related to pre-treatment BP levels of subjects and the type of control diet used as comparison.

Effects of end-stage renal disease and dialysis modalities on blood ammonia level

PubMed Central

VAZIRI, Nosratola D.; KHAZAELI, Mahyar; NUNES, Ane C. F.; HARLEY, Kevin T.; SAID, Hyder; ALIPOUR, Omeed; LAU, Wei Ling; PAHL, Madeleine V.

2018-01-01

Introduction Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 1 0-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Methods Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. Findings No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P<0.001) which was paradoxically accompanied by a modest but significant (P<0.05) rise in blood ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r=0.61, P<0.01). On subgroup analysis of patients who had a rise in blood ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r=0.88, P<0.01). The nadir intradialytic systolic blood pressure trended lower in the hemodialysis patients who had a rise in blood ammonia compared to the patients who manifested a fall in blood ammonia (124±8vs.136±6mmHg respectively, P=0.27). Discussion Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure. PMID:27804262

Effects of end-stage renal disease and dialysis modalities on blood ammonia level.

PubMed

Vaziri, Nosratola D; Khazaeli, Mahyar; Nunes, Ane C F; Harley, Kevin T; Said, Hyder; Alipour, Omeed; Lau, Wei Ling; Pahl, Madeleine V

2017-07-01

Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P < 0.001) which was paradoxically accompanied by a modest but significant (P < 0.05) rise in blood ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P < 0.01). On subgroup analysis of patients who had a rise in blood ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P < 0.01). The nadir intradialytic systolic blood pressure trended lower in the hemodialysis patients who had a rise in blood ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27). Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure. © 2016 International Society for Hemodialysis.

Pressure as a limit to bloater (Coregonus hoyi) vertical migration

USGS Publications Warehouse

TeWinkel, Leslie M.; Fleischer, Guy W.

1998-01-01

Observations of bloater vertical migration showed a limit to the vertical depth changes that bloater experience. In this paper, we conducted an analysis of maximum differences in pressure encountered by bloater during vertical migration. Throughout the bottom depths studied, bloater experienced maximum reductions in swim bladder volume equal to approximately 50-60% of the volume in midwater. The analysis indicated that the limit in vertical depth change may be related to a maximum level of positive or negative buoyancy for which bloater can compensate using alternative mechanisms such as hydrodynamic lift. Bloater may be limited in the extent of migration by either their depth of neutral buoyancy or the distance above the depth of neutral buoyancy at which they can still maintain their position in the water column. Although a migration limit for the bloater population was evident, individual distances of migration varied at each site. These variations in migration distances may indicate differences in depths of neutral buoyancy within the population. However, in spite of these variations, the strong correlation between shallowest depths of migration and swim bladder volume reduction across depths provides evidence that hydrostatic pressure limits the extent of daily vertical movement in bloater.

Active control of fan noise from a turbofan engine

NASA Technical Reports Server (NTRS)

Thomas, Russell H.; Burdisso, Ricardo A.; Fuller, Christopher R.; O'Brien, Walter F.

1993-01-01

A three channel active control system is applied to an operational turbofan engine in order to reduce tonal noise produced by both the fan and high pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provides blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. In order to minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three channel controller by up to 16 dB over a 60 deg angle about the engine axis. A single channel controller could produce reduction over a 30 deg angle. The experimental results show the control to be robust. Simultaneous control of two tones is done with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 dBA and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high pressure compressor fundamental tones.

Flight investigation of the use of a nose gear jump strut to reduce takeoff ground roll distance of STOL aircraft

NASA Technical Reports Server (NTRS)

Eppel, Joseph C.; Hardy, Gordon; Martin, James L.

1994-01-01

A series of flight tests was conducted to evaluate the reduction of takeoff ground roll distance obtainable from a rapid extension of the nose gear strut. The NASA Quiet Short-haul Research Aircraft (QSRA) used for this investigation is a transport-size short takeoff and landing (STOL) research vehicle with a slightly swept wing that employs the upper surface blowing (USB) concept to attain the high lift levels required for its low speed, short-field performance. Minor modifications to the conventional nose gear assembly and the addition of a high pressure pneumatic system and a control system provided the extendible nose gear, or 'jump strut,' capability. The limited flight test program explored the effects of thrust-to-weight ratio, storage tank initial pressure, and control valve open time duration on the ground roll distance. The data show that the predicted reduction of takeoff ground roll on the order of 10 percent was achieved with the use of the jump strut. Takeoff performance with the jump strut was also found to be essentially independent of the pneumatic supply pressure and was only slightly affected by control valve open time within the range of the parameters examined.

Regulation of Renin Secretion and Arterial Pressure During Prolonged Baroreflex Activation: Influence of Salt Intake

PubMed Central

Hildebrandt, Drew A.; Irwin, Eric D.; Cates, Adam W.; Lohmeier, Thomas E.

2014-01-01

Chronic electrical activation of the carotid baroreflex produces sustained reductions in sympathetic activity and arterial pressure and is currently being evaluated as antihypertensive therapy for patients with resistant hypertension. However, the influence of variations in salt intake on blood pressure lowering during baroreflex activation has not been determined. As sensitivity of arterial pressure to salt intake is linked to the responsiveness of renin secretion, we determined steady-state levels of arterial pressure and neurohormonal responses in 6 dogs on low, normal, and high salt intakes ( 5, 40, 450 mmol/day, respectively) under control conditions and during a 7-day constant level of baroreflex activation. Under control conditions, there was no difference in mean arterial pressure at low (92±1) and normal (92±2 mmHg) sodium intakes, but pressure increased 9 ±2 mmHg during high salt. Plasma renin activity (2.01±0.23, 0.93±0.20, 0.01±0.01 ng ANGI/mL/hr) and plasma aldosterone (10.3±1.9, 3.5±0.5, 1.7±0.1ng/dL) were inversely related to salt intake, whereas there were no changes in plasma norepinephrine. Although mean arterial pressure (19-22 mmHg) and norepinephrine (20-40%) were lower at all salt intakes during baroreflex activation, neither the changes in pressure nor the absolute values for plasma renin activity or aldosterone in response to salt were different from control conditions. These findings demonstrate that suppression of sympathetic activity by baroreflex activation lowers arterial pressure without increasing renin release and indicate that changes in sympathetic activity are not primary mediators of the effect of salt on renin secretion. Consequently, blood pressure lowering during baroreflex activation is independent of salt intake. PMID:24935941

Super, Red Palm and Palm Oleins Improve the Blood Pressure, Heart Size, Aortic Media Thickness and Lipid Profile in Spontaneously Hypertensive Rats

PubMed Central

Boon, Chee-Meng; Ng, Mei-Han; Choo, Yuen-May; Mok, Shiueh-Lian

2013-01-01

Background Oleic acid has been shown to lower high blood pressure and provide cardiovascular protection. Curiosity arises as to whether super olein (SO), red palm olein (RPO) and palm olein (PO), which have high oleic acid content, are able to prevent the development of hypertension. Methodology/Principal Findings Four-week-old male spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were fed 15% SO, RPO or PO supplemented diet for 15 weeks. After 15 weeks of treatment, the systolic blood pressure (SBP) of SHR treated with SO, RPO and PO were 158.4±5.0 mmHg (p<0.001), 178.9±2.7 mmHg (p<0.001) and 167.7±2.1 mmHg (p<0.001), respectively, compared with SHR controls (220.9±1.5 mmHg). Bradycardia was observed with SO and PO. In contrast, the SBP and heart rate of treated WKY rats were not different from those of WKY controls. The SO and PO significantly reduced the increased heart size and thoracic aortic media thickness observed in untreated SHR but RPO reduced only the latter. No such differences, however, were observed between the treated and untreated WKY rats. Oil Red O enface staining of thoracic-abdominal aorta did not show any lipid deposition in all treated rats. The SO and RPO significantly raised serum alkaline phosphatase levels in the SHR while body weight and renal biochemical indices were unaltered in both strains. Serum lipid profiles of treated SHR and WKY rats were unchanged, with the exception of a significant reduction in LDL-C level and total cholesterol/HDL ratio (atherogenic index) in SO and RPO treated SHR compared with untreated SHR. Conclusion The SO, RPO and PO attenuate the rise in blood pressure in SHR, accompanied by bradycardia and heart size reduction with SO and PO, and aortic media thickness reduction with SO, RPO and PO. The SO and RPO are antiatherogenic in nature by improving blood lipid profiles in SHR. PMID:23409085

Reducing the population's sodium intake: the UK Food Standards Agency's salt reduction programme.

PubMed

Wyness, Laura A; Butriss, Judith L; Stanner, Sara A

2012-02-01

To describe the UK Food Standards Agency's (FSA) salt reduction programme undertaken between 2003 and 2010 and to discuss its effectiveness. Relevant scientific papers, campaign materials and evaluations and consultation responses to the FSA's salt reduction programme were used. Adult salt intakes, monitored using urinary Na data collected from UK-wide surveys, indicate a statistically significant reduction in the population's average salt intake from 9·5 g/d in 2000-2001 to 8·6 g/d in 2008, which is likely to have health benefits. Reducing salt intake will have an impact on blood pressure; an estimated 6 % of deaths from CHD in the UK can be avoided if the number of people with high blood pressure is reduced by 50 %. Salt levels in food, monitored using commercial label data and information collected through an industry self-reporting framework, indicated that substantial reductions of up to 70 % in some foods had been achieved. The FSA's consumer campaign evaluation showed increased awareness of the benefits of reducing salt intake on health, with 43 % of adults in 2009 claiming to have made a special effort to reduce salt in their diet compared with 34 % of adults in 2004, before the campaign commenced. The UK's salt reduction programme successfully reduced the average salt intake of the population and increased consumers' awareness. Significant challenges remain in achieving the population average salt intake of 6 g/d recommended by the UK's Scientific Advisory Committee on Nutrition. However, the UK has demonstrated the success of its programme and this approach is now being implemented elsewhere in the world.

A large-scale cluster randomized trial to determine the effects of community-based dietary sodium reduction--the China Rural Health Initiative Sodium Reduction Study.

PubMed

Li, Nicole; Yan, Lijing L; Niu, Wenyi; Labarthe, Darwin; Feng, Xiangxian; Shi, Jingpu; Zhang, Jianxin; Zhang, Ruijuan; Zhang, Yuhong; Chu, Hongling; Neiman, Andrea; Engelgau, Michael; Elliott, Paul; Wu, Yangfeng; Neal, Bruce

2013-11-01

Cardiovascular diseases are the leading cause of death and disability in China. High blood pressure caused by excess intake of dietary sodium is widespread and an effective sodium reduction program has potential to improve cardiovascular health. This study is a large-scale, cluster-randomized, trial done in five Northern Chinese provinces. Two counties have been selected from each province and 12 townships in each county making a total of 120 clusters. Within each township one village has been selected for participation with 1:1 randomization stratified by county. The sodium reduction intervention comprises community health education and a food supply strategy based upon providing access to salt substitute. Subsidization of the price of salt substitute was done in 30 intervention villages selected at random. Control villages continued usual practices. The primary outcome for the study is dietary sodium intake level estimated from assays of 24-hour urine. The trial recruited and randomized 120 townships in April 2011. The sodium reduction program was commenced in the 60 intervention villages between May and June of that year with outcome surveys scheduled for October to December 2012. Baseline data collection shows that randomisation achieved good balance across groups. The establishment of the China Rural Health Initiative has enabled the launch of this large-scale trial designed to identify a novel, scalable strategy for reduction of dietary sodium and control of blood pressure. If proved effective, the intervention could plausibly be implemented at low cost in large parts of China and other countries worldwide. © 2013.

Sewage sludge solubilization by high-pressure homogenization.

PubMed

Zhang, Yuxuan; Zhang, Panyue; Guo, Jianbin; Ma, Weifang; Fang, Wei; Ma, Boqiang; Xu, Xiangzhe

2013-01-01

The behavior of sludge solubilization using high-pressure homogenization (HPH) treatment was examined by investigating the sludge solid reduction and organics solubilization. The sludge volatile suspended solids (VSS) decreased from 10.58 to 6.67 g/L for the sludge sample with a total solids content (TS) of 1.49% after HPH treatment at a homogenization pressure of 80 MPa with four homogenization cycles; total suspended solids (TSS) correspondingly decreased from 14.26 to 9.91 g/L. About 86.15% of the TSS reduction was attributed to the VSS reduction. The increase of homogenization pressure from 20 to 80 MPa or homogenization cycle number from 1 to 4 was favorable to the sludge organics solubilization, and the protein and polysaccharide solubilization linearly increased with the soluble chemical oxygen demand (SCOD) solubilization. More proteins were solubilized than polysaccharides. The linear relationship between SCOD solubilization and VSS reduction had no significant change under different homogenization pressures, homogenization cycles and sludge solid contents. The SCOD of 1.65 g/L was solubilized for the VSS reduction of 1.00 g/L for the three experimental sludge samples with a TS of 1.00, 1.49 and 2.48% under all HPH operating conditions. The energy efficiency results showed that the HPH treatment at a homogenization pressure of 30 MPa with a single homogenization cycle for the sludge sample with a TS of 2.48% was the most energy efficient.

A multi-level system quality improvement intervention to reduce racial disparities in hypertension care and control: study protocol

PubMed Central

2013-01-01

Background Racial disparities in blood pressure control have been well documented in the United States. Research suggests that many factors contribute to this disparity, including barriers to care at patient, clinician, healthcare system, and community levels. To date, few interventions aimed at reducing hypertension disparities have addressed factors at all of these levels. This paper describes the design of Project ReD CHiP (Reducing Disparities and Controlling Hypertension in Primary Care), a multi-level system quality improvement project. By intervening on multiple levels, this project aims to reduce disparities in blood pressure control and improve guideline concordant hypertension care. Methods Using a pragmatic trial design, we are implementing three complementary multi-level interventions designed to improve blood pressure measurement, provide patient care management services and offer expanded provider education resources in six primary care clinics in Baltimore, Maryland. We are staggering the introduction of the interventions and will use Statistical Process Control (SPC) charting to determine if there are changes in outcomes at each clinic after implementation of each intervention. The main hypothesis is that each intervention will have an additive effect on improvements in guideline concordant care and reductions in hypertension disparities, but the combination of all three interventions will result in the greatest impact, followed by blood pressure measurement with care management support, blood pressure measurement with provider education, and blood pressure measurement only. This study also examines how organizational functioning and cultural competence affect the success of the interventions. Discussion As a quality improvement project, Project ReD CHiP employs a novel study design that specifically targets multi-level factors known to contribute to hypertension disparities. To facilitate its implementation and improve its sustainability, we have incorporated stakeholder input and tailored components of the interventions to meet the specific needs of the involved clinics and communities. Results from this study will provide knowledge about how integrated multi-level interventions can improve hypertension care and reduce disparities. Trial Registration ClinicalTrials.gov NCT01566864 PMID:23734703

Effect of a Modest Weight Loss in Normalizing Blood Pressure in Obese Subjects on Antihypertensive Drugs.

PubMed

Gilardini, Luisa; Redaelli, Gabriella; Croci, Marina; Conti, Antonio; Pasqualinotto, Lucia; Invitti, Cecilia

2016-01-01

To assess the effect of a lifestyle intervention in lowering/normalizing blood pressure (BP) levels in hypertensive (controlled or not) obese patients. In this prospective observational study, 490 obese hypertensive patients, 389 controlled (BP < 140/90 mm Hg; CH) and 101 uncontrolled (BP ≥ 140/90 mm Hg; UH) attended a 3-month lifestyle intervention. Before and after the intervention we assessed weight, waist circumference, fat mass, BP, metabolic and renal variables, and physical activity. A multivariate regression model was used to determine the predictors of BP changes. 18.9% of CH and 20.0% of UH were on ≥ 3 antihypertensive drugs. Weight change (average -4.9 ± 2.7%) was independent of the antihypertensive drugs employed. Systolic BP (SBP) decreased by 23 mm Hg and diastolic BP (DBP) by 9 mm Hg, in patients with UH most of whom (89%) normalized BP levels (in 49% after a weight loss < 5%). Age, gender, whole and central obesity, concomitance of type 2 diabetes, chronic renal disease, physical activity intensification, and pharmacological therapy did not affect BP lowering. In the regression analysis with SBP change as dependent variable, weight reduction (β = 0.523, p = 0.005) and group (UH vs. CH, β = -19.40, p = 0.0005) remained associated with SBP reduction. When DBP change was entered as dependent variable, baseline uric acid remained associated with DBP reduction (β = 0.824, p < 0.05). Lifestyle interventions are useful for all obese hypertensive patients in most of whom a modest weight loss is sufficient to normalize BP levels avoiding the aggressive use of multiple antihypertensive drugs. © 2016 The Author(s) Published by S. Karger GmbH, Freiburg.

Effect of a Modest Weight Loss in Normalizing Blood Pressure in Obese Subjects on Antihypertensive Drugs

PubMed Central

Gilardini, Luisa; Redaelli, Gabriella; Croci, Marina; Conti, Antonio; Pasqualinotto, Lucia; Invitti, Cecilia

2016-01-01

Objective To assess the effect of a lifestyle intervention in lowering/normalizing blood pressure (BP) levels in hypertensive (controlled or not) obese patients. Methods In this prospective observational study, 490 obese hypertensive patients, 389 controlled (BP < 140/90 mm Hg; CH) and 101 uncontrolled (BP ≥ 140/90 mm Hg; UH) attended a 3-month lifestyle intervention. Before and after the intervention we assessed weight, waist circumference, fat mass, BP, metabolic and renal variables, and physical activity. A multivariate regression model was used to determine the predictors of BP changes. Results 18.9% of CH and 20.0% of UH were on ≥ 3 antihypertensive drugs. Weight change (average −4.9 ± 2.7%) was independent of the antihypertensive drugs employed. Systolic BP (SBP) decreased by 23 mm Hg and diastolic BP (DBP) by 9 mm Hg, in patients with UH most of whom (89%) normalized BP levels (in 49% after a weight loss < 5%). Age, gender, whole and central obesity, concomitance of type 2 diabetes, chronic renal disease, physical activity intensification, and pharmacological therapy did not affect BP lowering. In the regression analysis with SBP change as dependent variable, weight reduction (β = 0.523, p = 0.005) and group (UH vs. CH, β = −19.40, p = 0.0005) remained associated with SBP reduction. When DBP change was entered as dependent variable, baseline uric acid remained associated with DBP reduction (β = 0.824, p < 0.05). Conclusion Lifestyle interventions are useful for all obese hypertensive patients in most of whom a modest weight loss is sufficient to normalize BP levels avoiding the aggressive use of multiple antihypertensive drugs. PMID:27454447

Restoration of Pulsatile Flow Reduces Sympathetic Nerve Activity Among Individuals With Continuous-Flow Left Ventricular Assist Devices.

PubMed

Cornwell, William K; Tarumi, Takashi; Stickford, Abigail; Lawley, Justin; Roberts, Monique; Parker, Rosemary; Fitzsimmons, Catherine; Kibe, Julius; Ayers, Colby; Markham, David; Drazner, Mark H; Fu, Qi; Levine, Benjamin D

2015-12-15

Current-generation left ventricular assist devices provide circulatory support that is minimally or entirely nonpulsatile and are associated with marked increases in muscle sympathetic nerve activity (MSNA), likely through a baroreceptor-mediated pathway. We sought to determine whether the restoration of pulsatile flow through modulations in pump speed would reduce MSNA through the arterial baroreceptor reflex. Ten men and 3 women (54 ± 14 years) with Heartmate II continuous-flow left ventricular assist devices underwent hemodynamic and sympathetic neural assessment. Beat-to-beat blood pressure, carotid ultrasonography at the level of the arterial baroreceptors, and MSNA via microneurography were continuously recorded to determine steady-state responses to step changes (200-400 revolutions per minute) in continuous-flow left ventricular assist device pump speed from a maximum of 10,480 ± 315 revolutions per minute to a minimum of 8500 ± 380 revolutions per minute. Reductions in pump speed led to increases in pulse pressure (high versus low speed: 17 ± 7 versus 26 ± 12 mm Hg; P<0.01), distension of the carotid artery, and carotid arterial wall tension (P<0.05 for all measures). In addition, MSNA was reduced (high versus low speed: 41 ± 15 versus 33 ± 16 bursts per minute; P<0.01) despite a reduction in mean arterial pressure and was inversely related to pulse pressure (P=0.037). Among subjects with continuous-flow left ventricular assist devices, the restoration of pulsatile flow through modulations in pump speed leads to increased distortion of the arterial baroreceptors with a subsequent decline in MSNA. Additional study is needed to determine whether reduction of MSNA in this setting leads to improved outcomes. © 2015 American Heart Association, Inc.

Measuring Global Surface Pressures on a Circulation Control Concept Using Pressure Sensitive Paint

NASA Technical Reports Server (NTRS)

Watkins, Anthony N.; Lipford, William E.; Leighty, Bradley D.; Goodman, Kyle Z.; Goad, William K.

2012-01-01

This report will present the results obtained from the Pressure Sensitive Paint (PSP) technique on a circulation control concept model. This test was conducted at the National Transonic Facility (NTF) at the NASA Langley Research Center. PSP was collected on the upper wing surface while the facility was operating in cryogenic mode at 227 K (-50 oF). The test envelope for the PSP portion included Mach numbers from 0.7 to 0.8 with angle of attack varying between 0 and 8 degrees and a total pressure of approximately 168 kPa (24.4 psi), resulting in a chord Reynolds number of approximately 15 million. While the PSP results did exhibit high levels of noise in certain conditions (where the oxygen content of the flow was very small), some conditions provided good correlation between the PSP and pressure taps, showing the ability of the PSP technique. This work also served as a risk reduction opportunity for future testing in cryogenic conditions at the NTF.

Staged, High-Pressure Oxy-Combustion Technology: Development and Scale-Up

DOE Office of Scientific and Technical Information (OSTI.GOV)

Axelbaum, Richard; Kumfer, Benjamin; Gopan, Akshay

The immediate need for a high efficiency, low cost carbon capture process has prompted the recent development of pressurized oxy-combustion. With a greater combustion pressure the dew point of the flue gas is increased, allowing for effective integration of the latent heat of flue gas moisture into the Rankine cycle. This increases the net plant efficiency and reduces costs. A novel, transformational process, named Staged, Pressurized Oxy-Combustion (SPOC), achieves additional step changes in efficiency and cost reduction by significantly reducing the recycle of flue gas. The research and development activities conducted under Phases I and II of this project (FE0009702)more » include: SPOC power plant cost and performance modeling, CFD-assisted design of pressurized SPOC boilers, theoretical analysis of radiant heat transfer and ash deposition, boiler materials corrosion testing, construction of a 100 kWth POC test facility, and experimental testing. The results of this project have advanced the technology readiness level (TRL) of the SPOC technology from 1 to 5.« less

Effect of different pressure magnitudes on hypertrophic scar in a Chinese population.

PubMed

Candy, Lai Hoi Yan; Cecilia, Li-Tsang Wai Ping; Ping, Zheng Yong

2010-12-01

This study aimed to investigate the effect of different pressure magnitudes on treatment outcomes of hypertrophic scars, and determine pressure loss over time. A randomized clinical trial was adopted. 53 hypertrophic scar samples from 17 Chinese participants were recruited and randomly assigned into a high pressure group (20-25 mmHg) and low pressure group (10-15 mmHg) for a five-month intervention program. The scars were assessed objectively before intervention and monthly after intervention for thickness, color (redness, yellowness and lightness) and scar pliability. Pressure magnitude at each assessment was also measured. Two-way repeated ANOVA was used to compare for differences between groups. The results showed that both levels of pressure produced reduction in scar thickness and redness, but the improvement in the high pressure group was statistically better than that of the counterpart (both p<0.05). Monthly pressure measurement revealed that pressure loss in the high pressure group was more severe. However, no major changes in other color parameters and pliability were observed for both the groups. High pressure was demonstrated to be more effective for scar management, but it was also more prone to higher pressure loss. Pressure therapy integrated with regular monitoring of the interface pressure is suggested to improve its therapeutic efficacy. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

Korean Red Ginseng Improves Blood Pressure Stability in Patients with Intradialytic Hypotension

PubMed Central

Chen, I-Ju; Chang, Ming-Yang; Chiao, Sheng-Lin; Chen, Jiun-Liang; Yu, Chun-Chen; Yang, Sien-Hung; Liu, Ju-Mei; Hung, Cheng-Chieh; Yang, Rong-Chi; Chang, Hui-Chi; Hsu, Chung-Hua; Fang, Ji-Tseng

2012-01-01

Introduction. Intradialytic hypotension (IDH) is a common complication during hemodialysis which may increase mortality risks. Low dose of Korean red ginseng (KRG) has been reported to increase blood pressure. Whether KRG can improve hemodynamic stability during hemodialysis has not been examined. Methods. The 8-week study consisted of two phases: observation phase and active treatment phase. According to prehemodialysis blood pressure (BP), 38 patients with IDH were divided into group A (BP ≥ 140/90 mmHg, n = 18) and group B (BP < 140/90 mmHg, n = 20). Patients were instructed to chew 3.5 gm KRG slices at each hemodialysis session during the 4-week treatment phase. Blood pressure changes, number of sessions disturbed by symptomatic IDH, plasma levels of vasoconstrictors, blood biochemistry, and adverse effects were recorded. Results. KRG significantly reduced the degree of blood pressure drop during hemodialysis (P < 0.05) and the frequency of symptomatic IDH (P < 0.05). More activation of vasoconstrictors (endothelin-1 and angiotensin II) during hemodialysis was found. The postdialytic levels of endothelin-1 and angiotensin II increased significantly (P < 0.01). Conclusion. Chewing KRG renders IDH patients better resistance to acute BP reduction during hemodialysis via activation of vasoconstrictors. Our results suggest that KRG could be an adjuvant treatment for IDH. PMID:22645630

Effects of music intervention on physiological stress response and anxiety level of mechanically ventilated patients in China: a randomised controlled trial.

PubMed

Han, Lin; Li, Ji P; Sit, Janet W H; Chung, Loretta; Jiao, Zuo Y; Ma, Wei G

2010-04-01

To examine the effects of music intervention on the physiological stress response and the anxiety level among mechanically ventilated patients in intensive care unit. Despite the fact that previous studies have found music interventions to be effective in stress and anxiety reduction, effects of music on the Chinese population are inconclusive and warranted systematic study to evaluate its effect fully for a different Asian culture. A randomised placebo-controlled trial. A total of 137 patients receiving mechanical ventilation were randomly assigned to either music listening group, headphone group or control group. Outcome measures included the Chinese version of Spielberger State-Trait Anxiety Scale and physiological parameters (heart rate, respiratory rate, saturation of oxygen and blood pressure). Comparison of mean differences (pretest score-posttest score) showed significant differences in heart rate, respiratory rate, systolic blood pressure and diastolic blood pressure as well as the Chinese version of Spielberger State-Trait Anxiety Scale, but not in SaO(2) among the three groups (ranging from p < 0.001 to p = 0.007), of which greater mean differences were found in music listening group. A significant reduction in physiological stress response (heart rate and respiratory rate) over time was found in music listening group (p < 0.001 for both variables) and a significant increase in heart rate and respiratory rate over time in control group (p < 0.001 and p = 0.032), with no significant change over time in headphone group. Within group pretest-posttest comparison of the Chinese version of Spielberger State-Trait Anxiety Scale demonstrated a significant reduction in anxiety for the music listening group (p < 0.001) and headphone group (p < 0.001) but not the control group. Our findings confirm that short-term therapeutic effects of music listening results in substantial reduction in physiological stress responses arising from anxiety in mechanically ventilated patients. Music as a non-pharmacological nursing intervention can be used as complementary adjunct in the care of patients with low-energy states who tire easily, such as those requiring mechanical ventilator support.

The Efficacy of Low-Level Continuous Positive Airway Pressure for the Treatment of Snoring

PubMed Central

Guzman, Michelle A.; Sgambati, Francis P.; Pho, Huy; Arias, Rafael S.; Hawks, Erin M.; Wolfe, Erica M.; Ötvös, Tamás; Rosenberg, Russell; Dakheel, Riad; Schneider, Hartmut; Kirkness, Jason P.; Smith, Philip L.; Schwartz, Alan R.

2017-01-01

Study Objectives: To assess effects of low-level continuous positive airway pressure (CPAP) on snoring in habitual snorers without obstructive sleep apnea (OSA). Methods: A multicenter prospective in-laboratory reversal crossover intervention trial was conducted between September 2013 and August 2014. Habitual snorers were included if they snored (inspiratory sound pressure level ≥ 40 dBA) for ≥ 30% all sleep breaths on a baseline sleep study (Night 1), and if significant OSA and daytime somnolence were absent. Included participants then underwent a CPAP titration study at 2, 4, or 6 cm H2O (Night 2) to examine snoring responses to step-increases in nasal pressure, a treatment night at optimal pressure (Night 3), followed by baseline night (Night 4). At each pressure, snoring intensity was measured on each breath. Snoring frequency was quantified as a percentage of sleep breaths at thresholds of 40, 45, 50, and 55 dBA. Sleep architecture and OSA severity were characterized using standard measurements. Results: On baseline sleep studies, participants demonstrated snoring at ≥ 40 dBA on 53 ± 3% and ≥ 45 dBA on 35 ± 4% of breaths. Snoring frequency decreased progressively as nasal pressure increased from 0 to 4 cm H2O at each threshold, and plateaued thereafter. CPAP decreased snoring frequency by 67% and 85% at 40 and 45 dBA, respectively. Intervention did not alter sleep architecture and sleep apnea decreased minimally. Conclusions: Low-level CPAP below the range required to treat OSA diminished nocturnal snoring, and produced uniform reduction in nightly noise production below the World Health Organization's limit of 45 dBA. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT01949584. Citation: Guzman MA, Sgambati FP, Pho H, Arias RS, Hawks EM, Wolfe EM, Ötvös T, Rosenberg R, Dakheel R, Schneider H, Kirkness JP, Smith PL, Schwartz AR. The efficacy of low-level continuous positive airway pressure for the treatment of snoring. J Clin Sleep Med. 2017;13(5):703–711. PMID:28356182

Overweight is associated with lower serum leptin in Peruvian Indian than in Caucasian women: A dissociation contributing to low blood pressure?

PubMed

Lindgärde, F; Söderberg, S; Olsson, T; Ercilla, M B; Correa, L R; Ahrén, B

2001-03-01

We tested whether plasma levels of leptin and insulin are associated with the lower blood pressure in women of Peruvian Indian heritage compared with Caucasian women. A total of 181 women from Peru and 85 from Sweden, aged 20 to 60 years, with normal plasma glucose levels participated in the study. Measurements of anthropometry, blood pressure, and blood tests were performed after overnight fasting. Compared with women from Umeå in Sweden, women from Lima, Peru had higher body mass index (BMI) (26.2 +/- 4.9 v 24.4 +/- 3.8 kg/m(2)), waist circumference (85 +/- 11 v 79 +/- 10 cm), lower systolic blood pressure (99 +/- 15 v 114 +/- 14 mm; P <.001) and diastolic blood pressure (67 +/- 7 v 74 +/- 10 mm; P <.001). In addition, they had a reduction of the ratio of plasma leptin to BMI (0.52 +/- 0.22 v 0.61 +/- 0.36; P <.001), greater plasma insulin (80 +/- 42 v 41 +/- 21 pmol/L), but lower plasma glucose (4.2 +/- 0.5 v 5.1 +/- 0.5 mmol/L; P <.001). Furthermore, the 181 women from Lima had higher plasma triglyceride levels (1.5 +/- 0.8 v 1.3 +/- 0.7; P =.039), but lower plasma high-density lipoprotein (HDL)-cholesterol (1.0 +/- 0.2 v 1.5 +/- 0.4 mmol/L; P <.001) and total plasma cholesterol (5.0 +/- 1.1 v 5.9 +/- 1.3 mmol/L; P <.001) levels. Plasma leptin correlated with blood pressure and BMI in both populations (P <.001). In multiple regression analysis, BMI, but not log leptin, emerged as the determinant for systolic blood pressure. We concluded that women living in Lima have significant lower blood pressure levels in association with elevated plasma insulin concentrations, but lower plasma leptin values adjusted for BMI in comparison with women from northern Sweden. This may suggest that the concept of metabolic syndrome is different among women with Peruvian Indian heritage in comparison to a Caucasian population. Copyright 2001 by W.B. Saunders Company

Effect of modest salt reduction on blood pressure, urinary albumin, and pulse wave velocity in white, black, and Asian mild hypertensives.

PubMed

He, Feng J; Marciniak, Maciej; Visagie, Elisabeth; Markandu, Nirmala D; Anand, Vidya; Dalton, R Neil; MacGregor, Graham A

2009-09-01

A reduction in salt intake lowers blood pressure. However, most previous trials were in whites with few in blacks and Asians. Salt reduction may also reduce other cardiovascular risk factors (eg, urinary albumin excretion, arterial stiffness). However, few well-controlled trials have studied these effects. We carried out a randomized double-blind crossover trial of salt restriction with slow sodium or placebo, each for 6 weeks, in 71 whites, 69 blacks, and 29 Asians with untreated mildly raised blood pressure. From slow sodium to placebo, urinary sodium was reduced from 165+/-58 (+/-SD) to 110+/-49 mmol/24 hours (9.7 to 6.5 g/d salt). With this reduction in salt intake, there was a significant decrease in blood pressure from 146+/-13/91+/-8 to 141+/-12/88+/-9 mm Hg (P<0.001), urinary albumin from 10.2 (IQR: 6.8 to 18.9) to 9.1 (6.6 to 14.0) mg/24 hours (P<0.001), albumin/creatinine ratio from 0.81 (0.47 to 1.43) to 0.66 (0.44 to 1.22) mg/mmol (P<0.001), and carotid-femoral pulse wave velocity from 11.5+/-2.3 to 11.1+/-1.9 m/s (P<0.01). Subgroup analysis showed that the reductions in blood pressure and urinary albumin/creatinine ratio were significant in all groups, and the decrease in pulse wave velocity was significant in blacks only. These results demonstrate that a modest reduction in salt intake, approximately the amount of the current public health recommendations, causes significant falls in blood pressure in all 3 ethnic groups. Furthermore, it reduces urinary albumin and improves large artery compliance. Although both could be attributable to the falls in blood pressure, they may carry additional benefits on reducing cardiovascular disease above that obtained from the blood pressure falls alone.

Improvement of Expansive Soils Using Chemical Stabilizers

NASA Astrophysics Data System (ADS)

Ikizler, S. B.; Senol, A.; Khosrowshahi, S. K.; Hatipoğlu, M.

2014-12-01

The aim of this study is to investigate the effect of two chemical stabilizers on the swelling potential of expansive soil. A high plasticity sodium bentonite was used as the expansive soil. The additive materials including fly ash (FA) and lime (L) were evaluated as potential stabilizers to decrease the swelling pressure of bentonite. Depending on the type of additive materials, they were blended with bentonite in different percentages to assess the optimum state and approch the maximum swell pressure reduction. According to the results of swell pressure test, both fly ash and lime reduce the swelling potential of bentonite but the maximum improvement occurs using bentonite-lime mixture while the swelling pressure reduction approaches to 49%. The results reveal a significant reduction of swelling potential of expansive soil using chemical stabilizers. Keywords: Expansive soil; swell pressure; chemical stabilization; fly ash; lime

High pressure gas storage capacities. Example of a solution using filament windings

NASA Technical Reports Server (NTRS)

Phan, A.; Lamalle, J.

1981-01-01

The use of epoxy resin fiber glass and economic factors affecting the choice of materials for gas storage are discussed. The physical nature of the filament windings are described together with the results obtained. It is demonstrated that a substantial reduction in mass and an enhanced level of safety can be assured at a competitive cost by storing gases in this way.

Effect of Microjet Injection on Supersonic Jet Noise

NASA Technical Reports Server (NTRS)

Zaman, K. B. M. Q.; Podboy, G. G.

2010-01-01

The effect of microjet (jet) injection on the noise from supersonic jets is investigated. Three convergent-divergent (C-D) nozzles and one convergent nozzle, all having the same exit diameters, are used in the study. The jets are injected perpendicular to the primary jet close to the nozzle lip from six equally-spaced ports having a jet-to-primary-jet diameter ratio of 0.0054. Effects in the over-expanded, fully expanded as well as underexpanded flow regimes are explored. Relative to the effect on subsonic jets, larger reductions in the overall sound pressure level (OASPL) are achieved in most supersonic conditions. The largest reductions are typically associated with suppression of screech and transonic tones. For a shock-free, fully expanded case, the OASPL reductions achieved are comparable to that in the subsonic case; the same correlation, found for subsonic jet noise reduction at shallow observation angle, applies.

Pollution reduction technology program for small jet aircraft engines, phase 1

NASA Technical Reports Server (NTRS)

Bruce, T. W.; Davis, F. G.; Kuhn, T. E.; Mongia, H. C.

1977-01-01

A series of combustor pressure rig screening tests was conducted on three combustor concepts applied to the TFE731-2 turbofan engine combustion system for the purpose of evaluating their relative emissions reduction potential consistent with prescribed performance, durability, and envelope contraints. The three concepts and their modifications represented increasing potential for reducing emission levels with the penalty of increased hardware complexity and operational risk. Concept 1 entailed advanced modifications to the present production TFE731-2 combustion system. Concept 2 was based on the incorporation of an axial air-assisted airblast fuel injection system. Concept 3 was a staged premix/prevaporizing combustion system. Significant emissions reductions were achieved in all three concepts, consistent with acceptable combustion system performance. Concepts 2 and 3 were identified as having the greatest achievable emissions reduction potential, and were selected to undergo refinement to prepare for ultimate incorporation within an engine.

The effect of nimodipine on cerebral oxygenation in patients with poor-grade subarachnoid hemorrhage.

PubMed

Stiefel, Michael F; Heuer, Gregory G; Abrahams, John M; Bloom, Stephanie; Smith, Michelle J; Maloney-Wilensky, Eileen; Grady, M Sean; LeRoux, Peter D

2004-10-01

Nimodipine has been shown to improve neurological outcome after subarachnoid hemorrhage (SAH); the mechanism of this improvement, however, is uncertain. In addition, adverse systemic effects such as hypotension have been described. The authors investigated the effect of nimodipine on brain tissue PO2. Patients in whom Hunt and Hess Grade IV or V SAH had occurred who underwent aneurysm occlusion and had stable blood pressure were prospectively evaluated using continuous brain tissue PO2 monitoring. Nimodipine (60 mg) was delivered through a nasogastric or Dobhoff tube every 4 hours. Data were obtained from 11 patients and measurements of brain tissue PO2, intracranial pressure (ICP), mean arterial blood pressure (MABP), and cerebral perfusion pressure (CPP) were recorded every 15 minutes. Nimodipine resulted in a significant reduction in brain tissue PO2 in seven (64%) of 11 patients. The baseline PO2 before nimodipine administration was 38.4+/-10.9 mm Hg. The baseline MABP and CPP were 90+/-20 and 84+/-19 mm Hg, respectively. The greatest reduction in brain tissue PO2 occurred 15 minutes after administration, when the mean pressure was 26.9+/-7.7 mm Hg (p < 0.05). The PO2 remained suppressed at 30 minutes (27.5+/-7.7 mm Hg [p < 0.05]) and at 60 minutes (29.7+/-11.1 mm Hg [p < 0.05]) after nimodipine administration but returned to baseline levels 2 hours later. In the seven patients in whom brain tissue PO2 decreased, other physiological variables such as arterial saturation, end-tidal CO2, heart rate, MABP, ICP, and CPP did not demonstrate any association with the nimodipine-induced reduction in PO2. In four patients PO2 remained stable and none of these patients had a significant increase in brain tissue PO2. Although nimodipine use is associated with improved outcome following SAH, in some patients it can temporarily reduce brain tissue PO2.

Randomized comparison of renal denervation versus intensified pharmacotherapy including spironolactone in true-resistant hypertension: six-month results from the Prague-15 study.

PubMed

Rosa, Ján; Widimský, Petr; Toušek, Petr; Petrák, Ondřej; Čurila, Karol; Waldauf, Petr; Bednář, František; Zelinka, Tomáš; Holaj, Robert; Štrauch, Branislav; Šomlóová, Zuzana; Táborský, Miloš; Václavík, Jan; Kociánová, Eva; Branny, Marian; Nykl, Igor; Jiravský, Otakar; Widimský, Jiří

2015-02-01

This prospective, randomized, open-label multicenter trial evaluated the efficacy of catheter-based renal denervation (Symplicity, Medtronic) versus intensified pharmacological treatment including spironolactone (if tolerated) in patients with true-resistant hypertension. This was confirmed by 24-hour ambulatory blood pressure monitoring after excluding secondary hypertension and confirmation of adherence to therapy by measurement of plasma antihypertensive drug levels before enrollment. One-hundred six patients were randomized to renal denervation (n=52), or intensified pharmacological treatment (n=54) with baseline systolic blood pressure of 159±17 and 155±17 mm Hg and average number of drugs 5.1 and 5.4, respectively. A significant reduction in 24-hour average systolic blood pressure after 6 months (-8.6 [95% cofidence interval: -11.8, -5.3] mm Hg; P<0.001 in renal denervation versus -8.1 [95% cofidence interval: -12.7, -3.4] mm Hg; P=0.001 in pharmacological group) was observed, which was comparable in both groups. Similarly, a significant reduction in systolic office blood pressure (-12.4 [95% cofidence interval: -17.0, -7.8] mm Hg; P<0.001 in renal denervation versus -14.3 [95% cofidence interval: -19.7, -8.9] mm Hg; P<0.001 in pharmacological group) was present. Between-group differences in change were not significant. The average number of antihypertensive drugs used after 6 months was significantly higher in the pharmacological group (+0.3 drugs; P<0.001). A significant increase in serum creatinine and a parallel decrease of creatinine clearance were observed in the pharmacological group; between-group difference were borderline significant. The 6-month results of this study confirmed the safety of renal denervation. In conclusion, renal denervation achieved reduction of blood pressure comparable with intensified pharmacotherapy. © 2014 American Heart Association, Inc.

The effect of high pressures on the yoghurt from milk with the stabilizer

NASA Astrophysics Data System (ADS)

Reps, A.; Jankowska, A.; Wiśniewska, K.

2008-07-01

The effect of high pressures on the microbiological and physio-chemical properties of yoghurt was investigated. The best results were obtained when the yoghurt was manufactured from milk with the addition of MYO 752 stabilizer (starch, gelatin, pectin) selected from 10 stabilizers. Yoghurt manufactured with the addition of 0, 6% MYO 752 stabilizer was processed at the pressure of 400-600 MPa/15 min. in the range of 50 MPa. Pressurization caused a total reduction of number of Lactobacillus delbrueckii ssp. Bulgaricus and reduced the number of Streptococcus thermophilus by 1-2 orders of magnitude. Pressurized and non-pressurized yoghurts characterized of a homogenous consistency and typical plain yoghurt taste. The decrease of the number of living bacteria was observed in yoghurts during the storage. The acidity of pressurized yoghurts remained on the some level at the temperature of 4°C and 20°C. The more intensive antibacterial activity of microflora was observed in yoghurts storaged at 20°C in comparison with yoghurts storaged at 4°C. Disadvantageous changes of the pressurized yoghurts consistency were not found. The taste and aroma of yoghurts remained without any changes.

Oblateness, radius, and mean stratospheric temperature of Neptune from the 1985 August 20 occultation

NASA Technical Reports Server (NTRS)

Hubbard, W. B.; Nicholson, Philip D.; Lellouch, Emmanuel; Sicardy, Bruno; Brahic, Andre; Vilas, Faith

1987-01-01

The oblateness and equatorial radius of Neptune at the 1-microbar pressure level, together with the position angle of the projected spin axis, are the goals of a general oblate atmosphere model for Neptune employing a data ensemble obtained from the occultation of a bright IR star that provided accurate measurements of the limb position at these and several other stations. The observed reduction in central flash intensity is explained by a 150-135 K temperature decrease as pressure rises from 1 to 400 microbar. Attention is given to the implications of these oblateness results for models of the Neptune interior.

Bayesian identification of acoustic impedance in treated ducts.

PubMed

Buot de l'Épine, Y; Chazot, J-D; Ville, J-M

2015-07-01

The noise reduction of a liner placed in the nacelle of a turbofan engine is still difficult to predict due to the lack of knowledge of its acoustic impedance that depends on grazing flow profile, mode order, and sound pressure level. An eduction method, based on a Bayesian approach, is presented here to adjust an impedance model of the liner from sound pressures measured in a rectangular treated duct under multimodal propagation and flow. The cost function is regularized with prior information provided by Guess's [J. Sound Vib. 40, 119-137 (1975)] impedance of a perforated plate. The multi-parameter optimization is achieved with an Evolutionary-Markov-Chain-Monte-Carlo algorithm.

Development of Personalized Fitting Device With 3-Dimensional Solution for Prevention of NIV Oronasal Mask-Related Pressure Ulcers.

PubMed

Shikama, Maiko; Nakagami, Gojiro; Noguchi, Hiroshi; Mori, Taketoshi; Sanada, Hiromi

2018-05-22

Pressure ulcers related to oronasal masks used with noninvasive ventilation (NIV), along with patient discomfort, occur due to improper fit of the mask. We developed a personalized fitting device using a 3-dimensional (3D) scanning solution to prevent the formation of NIV mask-related pressure ulcers. This study aimed to evaluate the effectiveness of the proposed personalized fitting device. We conducted a randomized crossover experimental study of 20 healthy participants to study the use of this personalized fitting device between the face and an NIV mask designed with 3D solutions. The fitting device was not used under the NIV mask for the control. The outcome measures were the presence of blanchable erythema, standardized redness intensity, discomfort level, and contact pressure. The incidence of blanchable erythema and standardized redness intensity values were significantly lower for subjects who used the fitting device when worn for 30 min ( P < .001). The discomfort levels at the forehead, nasal bridge, and both cheeks, as well as leakage, were significantly reduced as well ( P = .008, P < .001, P = .001, P = .002, P = .001, P = .02, P < .001, P < .001, P < .001). Contact pressure at the nasal bridge, where pressure ulcers most frequently develop, was significantly decreased with the fitting device ( P < .001). Personalized fitting devices that incorporate 3D scanning solutions may contribute to the prevention of NIV mask-related pressure ulcers and the reduction of discomfort. Copyright © 2018 by Daedalus Enterprises.

Prevalence of Atherogenic Dyslipidemia in Spanish Hypertensive Patients and Its Relationship With Blood Pressure Control and Silent Organ Damage.

PubMed

de la Sierra, Alejandro; Gorostidi, Manuel; Aranda, Pedro; Corbella, Emili; Pintó, Xavier

2015-07-01

To assess the prevalence of atherogenic dyslipidemia in hypertensive patients and its relationship with risk profile and blood pressure control. The study included 24 351 hypertensive patients from the Spanish Ambulatory Blood Pressure Monitoring Registry. Atherogenic dyslipidemia was defined as the presence of hypertriglyceridemia (> 150mg/dL) and low levels of high-density lipoprotein cholesterol (< 40mg/dL in men and < 46mg/dL in women). Blood pressure control was assessed by office and ambulatory monitoring. Atherogenic dyslipidemia was present in 2705 patients (11.1%). Of these, 30% had hypertriglyceridemia and 21.7% had low levels of high-density lipoprotein cholesterol. Compared with patients without these risk factors, the former group were more often male (60% vs 52%), younger (57 years vs 59 years), had other risk factors and organ damage (microalbuminuria, reduced estimated glomerular filtration rate, and left ventricular hypertrophy), worse office, diurnal, and nocturnal blood pressure values (odds ratio 1.09, 1.06, and 1.10, respectively), and the lowest nocturnal blood pressure reduction (odds ratio=1.07), despite the greater use of antihypertensive drugs. Atherogenic dyslipidemia is present in more than 10% of hypertensive patients and is associated with other risk factors, organ damage, and poorer blood pressure control. Greater therapeutic effort is needed to reduce overall risk in these patients. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 7: High pressure fuel turbo-pump third stage impeller analysis

NASA Technical Reports Server (NTRS)

Pool, Kirby V.

1989-01-01

This volume summarizes the analysis used to assess the structural life of the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbo-Pump (HPFTP) Third Stage Impeller. This analysis was performed in three phases, all using the DIAL finite element code. The first phase was a static stress analysis to determine the mean (non-varying) stress and static margin of safety for the part. The loads involved were steady state pressure and centrifugal force due to spinning. The second phase of the analysis was a modal survey to determine the vibrational modes and natural frequencies of the impeller. The third phase was a dynamic response analysis to determine the alternating component of the stress due to time varying pressure impulses at the outlet (diffuser) side of the impeller. The results of the three phases of the analysis show that the Third Stage Impeller operates very near the upper limits of its capability at full power level (FPL) loading. The static loading alone creates stresses in some areas of the shroud which exceed the yield point of the material. Additional cyclic loading due to the dynamic force could lead to a significant reduction in the life of this part. The cyclic stresses determined in the dynamic response phase of this study are based on an assumption regarding the magnitude of the forcing function.

[Changes of right atrial myoendocrine cells during hypertension and after arterial pressure decrease].

PubMed

Maksimov, V F; Korostyshevskaia, I M; Kurganov, S A; Markel', A L; Rudenko, N S; Iakobson, G S

2014-01-01

It is well known now that atrial cardiomyocytes carry out both contractile and endocrine activities--they synthesize, accumulate in specific secretory granules and release the natriuretic peptides. The main physiological effects of natriuretic peptides are antagonistic to the renin-angiotensin-aldostrol system, but their role in the development of hypertension is still disputable. The aim of this investigation is to estimate using electron microscopy the secretory activities of atrial myoendocrine cells in rats with inherited stress-induced arterial hypertension (ISIAH stain). It has been shown that myoendocrine cells in the ISIAH rats with arterial pressure about 180 mm Hg reveal morphological features of increased synthesis, extra accumulation and release of natriuretic peptides compared with normotensive control rats. In the ISIAH rats treated with losartan (angiotensin II receptor blocker) and therefore having a sustained decrease in arterial pressure to 140 mm Hg, changes in granular pool composition, reduction of the number and diameter of the secretory granules, reduction of Golgi complexes, and increased intracellular degradation of secretory stores were found in the myoendocrine cells. At the same time the marked capillary hyperemia and interstitial edema in the myocardium were observed. Thus, in rats with severe inherited hypertension, the secretory activity of heart myoendocrine cells is sharply increased and directly depends on the arterial blood pressure level. This proves that natriuretic peptides actively participate in the regulation of hemodynamics during with cardiovascular pathology.

Metabolic syndrome and hypertension: regular exercise as part of lifestyle management.

PubMed

Lackland, Daniel T; Voeks, Jenifer H

2014-11-01

The incorporation of physical activity and exercise represents a clinically important aspect in the management of metabolic syndrome, hypertension, and diabetes. While the benefit of exercise and active lifestyles is well documented for prevention and risk reduction of cardiovascular and stroke outcomes, the detailed regiment and recommendations are less clear. The components of a prescribed physical activity include consideration of activity type, frequency of an activity, activity duration, and intensity of a specific physical movement. The exercise parameters prescribed as part of the management of metabolic syndrome, diabetes, and elevated blood pressure are most often proposed as separate documents while the general recommendations are similar. The evidence is strong such that physical activity and exercise recommendations in disease management guidelines are considered high quality. The general recommendations for both blood pressure and glycemic management include a regiment of physical activity with moderate- to high-intensity exercise of 30-min bouts on multiple days with a desired goal of a total of 150 min of exercise per week. While additional research is needed to identify the specific exercise/activity mode, frequencies for exercise training, intensity levels, and duration of exercise that achieve maximal blood pressure and glycemic lowering, this general recommendation showed a consistent and significant benefit in risk reduction. Similarly, the current available evidence also indicates that aerobic exercise, dynamic resistance exercise, and isometric exercises can lower blood pressure and improve glycemic control.

Addressing challenges for future strategic-level emergency management: reframing, networking, and capacity-building.

PubMed

Bosomworth, Karyn; Owen, Christine; Curnin, Steven

2017-04-01

The mounting frequency and intensity of natural hazards, alongside growing interdependencies between social-technical and ecological systems, are placing increased pressure on emergency management. This is particularly true at the strategic level of emergency management, which involves planning for and managing non-routine, high-consequence events. Drawing on the literature, a survey, and interviews and workshops with Australia's senior emergency managers, this paper presents an analysis of five core challenges that these pressures are creating for strategic-level emergency management. It argues that emphasising 'emergency management' as a primary adaptation strategy is a retrograde step that ignores the importance of addressing socio-political drivers of vulnerabilities. Three key suggestions are presented that could assist the country's strategic-level emergency management in tackling these challenges: (i) reframe emergency management as a component of disaster risk reduction rather than them being one and the same; (ii) adopt a network governance approach; and (iii) further develop the capacities of strategic-level emergency managers. © 2017 The Author(s). Disasters © Overseas Development Institute, 2017.

In-shoe plantar pressure measurements for the evaluation and adaptation of foot orthoses in patients with rheumatoid arthritis: A proof of concept study.

PubMed

Tenten-Diepenmaat, Marloes; Dekker, Joost; Steenbergen, Menno; Huybrechts, Elleke; Roorda, Leo D; van Schaardenburg, Dirkjan; Bus, Sicco A; van der Leeden, Marike

2016-03-01

Improving foot orthoses (FOs) in patients with rheumatoid arthritis (RA) by using in-shoe plantar pressure measurements seems promising. The objectives of this study were to evaluate (1) the outcome on plantar pressure distribution of FOs that were adapted using in-shoe plantar pressure measurements according to a protocol and (2) the protocol feasibility. Forty-five RA patients with foot problems were included in this observational proof-of concept study. FOs were custom-made by a podiatrist according to usual care. Regions of Interest (ROIs) for plantar pressure reduction were selected. According to a protocol, usual care FOs were evaluated using in-shoe plantar pressure measurements and, if necessary, adapted. Plantar pressure-time integrals at the ROIs were compared between the following conditions: (1) no-FO versus usual care FO and (2) usual care FO versus adapted FO. Semi-structured interviews were held with patients and podiatrists to evaluate the feasibility of the protocol. Adapted FOs were developed in 70% of the patients. In these patients, usual care FOs showed a mean 9% reduction in pressure-time integral at forefoot ROIs compared to no-FOs (p=0.01). FO adaptation led to an additional mean 3% reduction in pressure-time integral (p=0.05). The protocol was considered feasible by patients. Podiatrists considered the protocol more useful to achieve individual rather than general treatment goals. A final protocol was proposed. Using in-shoe plantar pressure measurements for adapting foot orthoses for patients with RA leads to a small additional plantar pressure reduction in the forefoot. Further research on the clinical relevance of this outcome is required. Copyright © 2016. Published by Elsevier B.V.

Parenting stress, salivary biomarkers, and ambulatory blood pressure: a comparison between mothers and fathers of children with autism spectrum disorders.

PubMed

Foody, Ciara; James, Jack E; Leader, Geraldine

2015-04-01

Parents of children with autism spectrum disorders (ASD) may experience higher levels of stress and health problems than parents of children with typical development. However, most research has focused on mothers, with emphasis on parent-reported stress and wellbeing. This study compared parenting responsibility, distress, anxiety, depression, cortisol, alpha-amylase, and cardiovascular activity between 19 mother-father dyads of children with ASD. Mothers reported higher parenting responsibility, distress, anxiety, and depression than fathers, while fathers had higher blood pressure and heart rate variability. Mothers and fathers had lower than average morning cortisol levels, suggesting stress effects on the hypothalamic-pituitary-adrenal-axis. Parents of children with ASD may benefit from routine health screening (particularly adrenal and cardiovascular function) and referral for stress reduction interventions or supports.

Investigation of Thrust Augmentation and Acoustic Performance by Ejectors on PDE

NASA Astrophysics Data System (ADS)

Xu, Gui-yang; Weng, Chun-sheng; Li, Ning; Huang, Xiao-long

2016-04-01

Thrust augmentation and acoustic performance of a Pulse Detonation Engine (PDE) with ejector system is experimentally investigated. For these tests the LEjector/DEjector is varied from 1.18 to 4 and the axial placement of the ejector relative to the PDE exhaust is varied from an x/DPDE of -3 to 3. Results from the tests show that the optimum LEjector/DEjector based on thrust augmentation and Overall Sound Pressure Level (OASPL) is found to be 2.61. The divergent ejector performed the best based on thrust augmentation, while the reduction effect for OASPL and Peak Sound Pressure Level (PSPL) at 60° is most prominent for the convergent ejector. The optimum axial position based on thrust augmentation is determined to be x/DPDE = 2, while, x/DPDE = 0 based on OASPL and PSPL.

[Bio-electrochemical effect on hydrogenotrophic sulfate reduction stimulated by electrical field in the presence of H2 under atmospheric pressure].

PubMed

Xu, Hui-Wei; Zhang, Xu; Yang, Shan-Shan; Li, Guang-He

2009-07-15

Microbial sulfate reduction rate is limited with H2 as electron donor. In order to improve hydrogenotrophic sulfate reduction under normal atmospheric H2 pressure, a bio-electrochemical system with direct current was designed and performed in this study. Results indicates that sulfate reduction rate (SRR) increases with the augment of current intensity under lower current intensity (I < or = 1.50 mA). When optimum current intensity of 1.50 mA is applied, the SRR is 1.7 to 2.1 times higher than that of the control reactor. The synergistic effect of electrochemistry and microbiology on sulfate reduction varies at different current intensity. Under the condition of I < or = 1.50 mA, the most probable mechanism of SRR increase is that electric or magnetic field stimulates the proliferation of sulfate-reducing bacteria (SRB) and the activity of the enzymes. When I is higher than 1.50 mA, the activity of SRB is inhibited, resulting in lower reduction rate compared with that at lower current. If controlling the cathode potential lower than -0.69 V and H2 partial pressure 1.01 x 10(5) Pa, electro-catalytic sulfate reduction process takes place with H2 as reductant in this bio-electrochemical system. However, the overall reduction rate is still lower than that when I = 1.50 mA is applied, and additionally the energy consumption is much higher. Therefore, electric field of low intensity can enhance hydrogenotrophic sulfate reduction in the presence of H2 under atmospheric pressure.

Statistical analysis of the El Niño-Southern Oscillation and sea-floor seismicity in the eastern tropical Pacific.

PubMed

Guillas, Serge; Day, Simon J; McGuire, B

2010-05-28

We present statistical evidence for a temporal link between variations in the El Niño-Southern Oscillation (ENSO) and the occurrence of earthquakes on the East Pacific Rise (EPR). We adopt a zero-inflated Poisson regression model to represent the relationship between the number of earthquakes in the Easter microplate on the EPR and ENSO (expressed using the southern oscillation index (SOI) for east Pacific sea-level pressure anomalies) from February 1973 to February 2009. We also examine the relationship between the numbers of earthquakes and sea levels, as retrieved by Topex/Poseidon from October 1992 to July 2002. We observe a significant (95% confidence level) positive influence of SOI on seismicity: positive SOI values trigger more earthquakes over the following 2 to 6 months than negative SOI values. There is a significant negative influence of absolute sea levels on seismicity (at 6 months lag). We propose that increased seismicity is associated with ENSO-driven sea-surface gradients (rising from east to west) in the equatorial Pacific, leading to a reduction in ocean-bottom pressure over the EPR by a few kilopascal. This relationship is opposite to reservoir-triggered seismicity and suggests that EPR fault activity may be triggered by plate flexure associated with the reduced pressure.

Safety and efficacy of combined epidural/general anesthesia during major abdominal surgery in patients with increased intracranial pressure: a cohort study.

PubMed

Zabolotskikh, Igor; Trembach, Nikita

2015-05-15

The increased intracranial pressure can significantly complicate the perioperative period in major abdominal surgery, increasing the risk of complications, the length of recovery from the surgery, worsening the outcome. Epidural anesthesia has become a routine component of abdominal surgery, but its use in patients with increased intracranial pressure remains controversial. The goal of the study was to evaluate the safety and efficacy of epidural anesthesia, according to monitoring of intracranial pressure in patients with increased intracranial pressure. The study includes 65 surgical patients who were routinely undergone the major abdominal surgery under combined epidural/general anesthesia. Depending on the initial ICP all patients were divided into 2 groups: 1 (N group) - patients with the normal intracranial pressure (≤12 mm Hg, n = 35) and 2 (E group) - patients with the elevated intracranial pressure (ICP > 12 mm Hg, n = 30). During the surgery we evaluated ICP, blood pressure, cerebral perfusion pressure (CPP). The parameters of recovery from anesthesia and the effectiveness of postoperative analgesia were also assessed. In N group ICP remained stable. In E group ICP decreased during anesthesia, the overall decline was 40% at the end of the operation (from 15 to 9 mm Hg (P <0.05)). The correction of MAP with vasopressors to maintain normal CPP was required mainly in patients with increased ICP (70% vs. 45%, p <0.05). CPP declined by 19% in N group. In E group the CPP reduction was 23%, and then it remained stable at 60 mm Hg. No significant differences in time of the recovery of consciousness, effectiveness of postoperative analgesia and complications between patients with initially normal levels of ICP and patients with ICH were noted. The combination of general and epidural anesthesia is safe and effective in patients with increased intracranial pressure undergoing elective abdominal surgery under the condition of maintaining the arterial pressure. Its use is not associated with the increase in intracranial pressure during the anesthesia, but it needs an intraoperative monitoring of ICP in order to prevent CPP reduction.

Increased Notch3 Activity Mediates pathological Changes in Structure of Cerebral arteries

PubMed Central

Baron-Menguy, Celine; Domenga-Denier, Valérie; Ghezali, Lamia; Faraci, Frank; Joutel, Anne

2016-01-01

CADASIL, the most frequent genetic cause of stroke and vascular dementia, is caused by highly stereotyped mutations in the NOTCH3 receptor, which is predominantly expressed in vascular smooth muscle. The well-established TgNotch3R169C mouse model develops characteristic features of the human disease, with deposition of NOTCH3 and other proteins, including TIMP3 (tissue inhibitor of metalloproteinase 3), on brain vessels as well as reduced maximal dilation, and attenuated myogenic tone of cerebral arteries, but without elevated blood pressure. Increased TIMP3 levels were recently shown to be a major determinant of altered myogenic tone. In this study, we investigated the contribution of TIMP3 and Notch3 signaling to the impairment of maximal vasodilator capacity caused by the archetypal R169C mutation. Maximally dilated cerebral arteries in TgNotch3R169C mice exhibited a decrease in lumen diameter over a range of physiological pressures that occurred prior to myogenic tone deficits. This defect was not prevented by genetic reduction of TIMP3 in TgNotch3R169C mice and was not observed in mice overexpressing TIMP3. Knock-in mice with the R169C mutation (Notch3R170C/R170C) exhibited similar reductions in arterial lumen, and both TgNotch3R169C and Notch3R170C/R170C mice showed increased cerebral artery expression of Notch3 target genes. Reduced maximal vasodilation was prevented by conditional reduction of Notch activity in smooth muscle of TgNotch3R169C mice and mimicked by conditional activation of Notch3 in smooth muscle, an effect that was blood pressure-independent. We conclude that increased Notch3 activity mediates reduction in maximal dilator capacity of cerebral arteries in CADASIL and may contribute to reductions in cerebral blood flow. PMID:27821617

Increased Notch3 Activity Mediates Pathological Changes in Structure of Cerebral Arteries.

PubMed

Baron-Menguy, Celine; Domenga-Denier, Valérie; Ghezali, Lamia; Faraci, Frank M; Joutel, Anne

2017-01-01

CADASIL (Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy), the most frequent genetic cause of stroke and vascular dementia, is caused by highly stereotyped mutations in the NOTCH3 receptor, which is predominantly expressed in vascular smooth muscle. The well-established TgNotch3 R169C mouse model develops characteristic features of the human disease, with deposition of NOTCH3 and other proteins, including TIMP3 (tissue inhibitor of metalloproteinase 3), on brain vessels, as well as reduced maximal dilation, and attenuated myogenic tone of cerebral arteries, but without elevated blood pressure. Increased TIMP3 levels were recently shown to be a major determinant of altered myogenic tone. In this study, we investigated the contribution of TIMP3 and Notch3 signaling to the impairment of maximal vasodilator capacity caused by the archetypal R169C mutation. Maximally dilated cerebral arteries in TgNotch3 R169C mice exhibited a decrease in lumen diameter over a range of physiological pressures that occurred before myogenic tone deficits. This defect was not prevented by genetic reduction of TIMP3 in TgNotch3 R169C mice and was not observed in mice overexpressing TIMP3. Knock-in mice with the R169C mutation (Notch3 R170C/R170C ) exhibited similar reductions in arterial lumen, and both TgNotch3 R169C and Notch3 R170C/R170C mice showed increased cerebral artery expression of Notch3 target genes. Reduced maximal vasodilation was prevented by conditional reduction of Notch activity in smooth muscle of TgNotch3 R169C mice and mimicked by conditional activation of Notch3 in smooth muscle, an effect that was blood pressure-independent. We conclude that increased Notch3 activity mediates reduction in maximal dilator capacity of cerebral arteries in CADASIL and may contribute to reductions in cerebral blood flow. © 2016 American Heart Association, Inc.

The effects of endothelin-1 on the cardiorespiratory physiology of the freshwater trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias).

PubMed

Perry, S F; Montpetit, C J; McKendry, J; Desforges, P R; Gilmour, K M; Wood, C M; Olson, K R

2001-11-01

The aim of the present study was to evaluate the effects of endothelin-l-elicited cardiovascular events on respiratory gas transfer in the freshwater rainbow trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias). In both species, endothelin-1 (666 pmol kg(-1)) caused a rapid (within 4 min) reduction (ca. 30-50 mmHg) in arterial blood partial pressure of O2. The effects of endothelin-1 on arterial blood partial pressure of CO2 were not synchronised with the changes in O2 partial pressure and the responses were markedly different in trout and dogfish. In trout, arterial CO2 partial pressure was increased transiently by approximately 1.0 mmHg but the onset of the response was delayed and occurred 12 min after endothelin-1 injection. In contrast, CO2 partial pressure remained more-or-less constant in dogfish after injection of endothelin-1 and was increased only slightly (approximately 0.1 mmHg) after 60 min. Pre-treatment of trout with bovine carbonic anhydrase (5 mg ml(-1)) eliminated the increase in CO2 partial pressure that was normally observed after endothelin-1 injection. In both species, endothelin-1 injection caused a decrease in arterial blood pH that mirrored the changes in CO2 partial pressure. Endothelin-1 injection was associated with transient (trout) or persistent (dogfish) hyperventilation as indicated by pronounced increases in breathing frequency and amplitude. In trout, arterial blood pressure remained constant or was decreased slightly and was accompanied by a transient increase in systemic resistance, and a temporary reduction in cardiac output. The decrease in cardiac output was caused solely by a reduction in cardiac frequency; cardiac stroke volume was unaffected. In dogfish, arterial blood pressure was lowered by approximately 10 mmHg at 6-10 min after endothelin-1 injection but then was rapidly restored to pre-injection levels. The decrease in arterial blood pressure reflected an increase in branchial vascular resistance (as determined using in situ perfused gill preparations) that was accompanied by simultaneous decreases in systemic resistance and cardiac output. Cardiac frequency and stroke volume were reduced by endothelin-1 injection and thus both variables contributed to the changes in cardiac output. We conclude that the net consequences of endothelin-1 on arterial blood gases result from the opposing effects of reduced gill functional surface area (caused by vasoconstriction) and an increase in blood residence time within the gill (caused by decreased cardiac output.

Raisins compared with other snack effects on glycemia and blood pressure: a randomized, controlled trial.

PubMed

Anderson, James W; Weiter, Kathy M; Christian, Amber L; Ritchey, Michelle B; Bays, Harold E

2014-01-01

To compare effects of raisin snacks with conventional snacks on glycemia and cardiovascular risk factors. A 12-week, randomized, controlled trial compared 3-times-a-day consumption of raisins with intake of processed snacks on glycemia and cardiovascular risk factors. Men and women were randomized to snacks (n = 15) or raisins (n = 31). Outcome measures were performed at baseline, 4, 8, and 12 weeks. Fasting plasma glucose levels were not significantly affected by intake of raisins or snacks. Mean subject post prandial glucose levels were significantly reduced by raisin intake at 12 weeks; changes with raisin intake were -13.1 mg/dL (P = 0.003 vs baseline; P = 0.03 vs snacks). Eating raisins significantly decreased glycated hemoglobin (HbA1c) level (-0.12%; P = 0.004), a significantly greater level decrease than seen with snack intake (P = 0.036). Snack intake did not significantly affect subject systolic or diastolic blood pressure (BP). Raisin intake was associated with reductions in systolic blood pressure (SBP) at 4, 8, and 12 weeks with mean changes of -6.0 to 10.2 mmHg; all these changes were statistically significant (P = 0.015 to 0.001). Raisins were associated with significantly greater changes in diastolic blood pressure (DBP) at 4, 8, and 12 weeks than snacks (P < 0.05). Body weight did not significantly change within or between groups. Regular consumption of raisins may reduce glycemia and cardiovascular risk factors, including BP rate.

Does bacteremia occur during high pressure lavage of contaminated wounds?

PubMed

Tabor, O B; Bosse, M J; Hudson, M C; Greene, K G; Nousiainen, M T; Meyer, R A; Sims, S H; Kellam, J F

1998-02-01

The risk of bacteremia secondary to high pressure lavage of contaminated wounds was assessed. Twenty canines were divided randomly into four treatment groups. A 10-cm incision was made over the left shoulder of each dog. The deltoideus muscle was disrupted and traumatized. Groups A and B (n = 8) had wound contamination with 1.4 x 10(9) Staphylococcus aureus followed 75 minutes later by high pressure lavage or bulb syringe irrigation, respectively. Groups C and D (n = 2) had no contamination, followed by the same treatment. Bacterial counts were obtained before and after wound irrigation. Blood cultures were obtained before, during, and 15 minutes after irrigation. Positive control cultures were obtained during injection of bacteria into the antecubital vein. A detectable bacteremia did not occur during or after high pressure lavage or bulb syringe irrigation of acute contaminated wounds but did occur in 18 of 20 positive controls. Bacterial levels were reduced by an average of 70% +/- 10% by high pressure lavage and 44% +/- 50% by bulb irrigation. Reduction of wound bacteria was achieved more consistently with high pressure lavage than with bulb syringe irrigation.

Review of noise reduction methods for centrifugal fans

NASA Astrophysics Data System (ADS)

Neise, W.

1981-11-01

Several methods for the reduction of centrifugal fan noise are presented, the most of which are aimed at a lower blade passage frequency level. The methods are grouped into five categories: casing modifications to increase the distance between impeller and cutoff, the introduction of a phase shift of the source pressure fluctuations, impeller modifications, radial clearance between impeller eye and inlet nozzle, and acoustical measures. Resonators mounted at the cutoff of centrifugal fans appear to be a highly efficient and simple means of reducing the blade passage tone, and the method can be used for new fan construction and existing installations without affecting the aerodynamic performance of the fan.

Estimating risk reduction required to break even in a health promotion program.

PubMed

Ozminkowski, Ronald J; Goetzel, Ron Z; Santoro, Jan; Saenz, Betty-Jo; Eley, Christine; Gorsky, Bob

2004-01-01

To illustrate a formula to estimate the amount of risk reduction required to break even on a corporate health promotion program. A case study design was implemented. Base year (2001) health risk and medical expenditure data from the company, along with published information on the relationships between employee demographics, health risks, and medical expenditures, were used to forecast demographics, risks, and expenditures for 2002 through 2011 and estimate the required amount of risk reduction. Motorola. 52,124 domestic employees. Demographics included age, gender, race, and job type. Health risks for 2001 were measured via health risk appraisal. Risks were noted as either high or low and related to exercise/eating habits, body weight, blood pressure, blood sugar levels, cholesterol levels, depression, stress, smoking/drinking habits, and seat belt use. Medical claims for 2001 were used to calculate medical expenditures per employee. Assuming a dollar 282 per employee program cost, Motorola employees would need to reduce their lifestyle-related health risks by 1.08% to 1.42% per year to break even on health promotion programming, depending upon the discount rate. Higher or lower program investments would change the risk reduction percentages. Employers can use information from published studies, along with their own data, to estimate the amount of risk reduction required to break even on their health promotion programs.

Lower Sodium Intake and Risk of Headaches: Results From the Trial of Nonpharmacologic Interventions in the Elderly

PubMed Central

Chen, Liwei; Zhang, Zhenzhen; Chen, Wen; Whelton, Paul K.; Appel, Lawrence J.

2016-01-01

Objectives To determine the effect of sodium (Na) reduction on occurrence of headaches. Methods In the Trial of Nonpharmacologic Interventions in the Elderly, 975 men and woman (aged 60–80 years) with hypertension were randomized to a Na-reduction intervention or control group and were followed for up to 36 months. The study was conducted between 1992 and 1995 at 4 clinical centers (Johns Hopkins University, Wake Forest University School of Medicine, Robert Wood Johnson Medical School, and the University of Tennessee). Results Mean difference in Na excretion between the Na-reduction intervention and control group was significant at each follow-up visit (P < .001) with an average difference of 38.8 millimoles per 24 hours. The occurrence of headaches was significantly lower in the Na-reduction intervention group (10.5%) compared with control (14.3%) with a hazard ratio of 0.59 (95% confidence interval = 0.40, 0.88; P = .009). The risk of headaches was significantly associated with average level of Na excretion during follow-up, independent of most recent blood pressure. The relationship appeared to be nonlinear with a spline relationship and a knot at 150 millimoles per 24 hours. Conclusions Reduced sodium intake, currently recommended for blood pressure control, may also reduce the occurrence of headaches in older persons with hypertension. PMID:27077348

Rotorcraft In-Plane Noise Reduction Using Active/Passive Approaches with Induced Vibration Tracking

NASA Astrophysics Data System (ADS)

Chia, Miang Hwee

A comprehensive study of the use of active and passive approaches for in-plane noise reduction, including the vibrations induced during noise reduction, was conducted on a hingeless rotor configuration resembling the MBB BO-105 rotor. First, a parametric study was performed to examine the effects of rotor blade stiffness on the vibration and noise reduction performance of a 20%c plain trailing edge flap and a 1.5%c sliding microflap. This was accomplished using a comprehensive code AVINOR (for Active VIbration and NOise Reduction). A two-dimensional unsteady reduced order aerodynamic model (ROM), using the Rational Function Approximation approach and CFD-based oscillatory aerodynamic load data, was used in the comprehensive code. The study identified a hingeless blade configuration with torsional frequency of 3.17/rev as an optimum configuration for studying vibration and noise reduction using on-blade control devices such as flaps or microflaps. Subsequently, a new suite of computational tools capable of predicting in-plane low frequency sound pressure level (LFSPL) rotorcraft noise and its control was developed, replacing the acoustic module WOPWOP in AVINOR with a new acoustic module HELINOIR (for HELIcopter NOIse Reduction), which overcomes certain limitations associated with WOPWOP. The new suite, consisting of the AVINOR/HELINOIR combination, was used to study active flaps, as well as microflaps operating in closed-loop mode for in-plane noise reduction. An alternative passive in-plane noise reduction approach using modification to the blade tip in the 10%R outboard region was also studied. The new suite consisting of the AVINOR/HELINOIR combination based on a compact aeroacoustic model was validated by comparing with wind tunnel test results, and subsequently verified by comparing with computational results. For active control, the in-plane noise reduction obtained with a single 20%c plain trailing edge flap during level flight at a moderate advance ratio was examined. Different configurations of far-field and near-field feedback microphone locations were examined to develop a fundamental understanding of the feedback microphone locations on the noise reduction process A near-field microphone located on the tip of a nose boom was found to produce a LFSPL reduction of up to 6dB. However, this noise reduction was accompanied by an out-of-plane noise increase of 18dB and 60% increase in vertical hub shear. For passive control, three tip geometries having sweep, dihedral, and anhedral, were considered. The tip dihedral reduced LFSPL by up to 2dB without a vibratory load penalty. However, this was accompanied by an increase in the mid frequency sound pressure levels (MFSPL). The tip sweep and tip anhedral produced an increase in in-plane LFSPL below the horizon. A comparison of the active and passive approaches indicated that active approaches implemented by a plain flap with a feedback microphone located on the nose boom is superior to the passive control approaches. However, there is a general trade-off between LFSPL reduction, MFSPL generation and vibratory hub loads induced by noise control.

Determinants of systemic zero-flow arterial pressure.

PubMed

Brunner, M J; Greene, A S; Sagawa, K; Shoukas, A A

1983-09-01

Thirteen pentobarbital-anesthetized dogs whose carotid sinuses were isolated and perfused at a constant pressure were placed on total cardiac bypass. With systemic venous pressure held at 0 mmHg (condition 1), arterial inflow was stopped for 20 s at intrasinus pressures of 50, 125, and 200 mmHg. Zero-flow arterial pressures under condition 1 were 16.2 +/- 1.3 (SE), 13.8 +/- 1.1, and 12.5 +/- 0.8 mmHg, respectively. In condition 2, the venous outflow tube was clamped at the instant of stopping the inflow, causing venous pressure to rise. The zero-flow arterial pressures were 19.7 +/- 1.3, 18.5 +/- 1.4, and 16.4 +/- 1.2 mmHg for intrasinus pressures of 50, 125, and 200 mmHg, respectively. At all levels of intrasinus pressure, the zero-flow arterial pressure in condition 2 was higher (P less than 0.005) than in condition 1. In seven dogs, at an intrasinus pressure of 125 mmHg, epinephrine increased the zero-flow arterial pressure by 3.0 mmHg, whereas hexamethonium and papaverine decreased the zero-flow arterial pressure by 2 mmHg. Reductions in the hematocrit from 52 to 11% resulted in statistically significant changes (P less than 0.01) in zero-flow arterial pressures. Thus zero-flow arterial pressure was found to be affected by changes in venous pressure, hematocrit, and vasomotor tone. The evidence does not support the literally interpreted concept of the vascular waterfall as the model for the finite arteriovenous pressure difference at zero flow.

Response of the water status of soybean to changes in soil water potentials controlled by the water pressure in microporous tubes.

PubMed

Steinberg, S L; Henninger, D L

1997-12-01

Water transport through a microporous tube-soil-plant system was investigated by measuring the response of soil and plant water status to step change reductions in the water pressure within the tubes. Soybeans were germinated and grown in a porous ceramic 'soil' at a porous tube water pressure of -0.5 kpa for 28 d. During this time, the soil matric potential was nearly in equilibrium with tube water pressure. Water pressure in the porous tubes was then reduced to either -1.0, -1.5 or -2.0 kPa. Sap flow rates, leaf conductance and soil, root and leaf water potentials were measured before and after this change. A reduction in porous tube water pressure from -0.5 to -1.0 or -1.5 kPa did not result in any significant change in soil or plant water status. A reduction in porous tube water pressure to -2.0 kPa resulted in significant reductions in sap flow, leaf conductance, and soil, root and leaf water potentials. Hydraulic conductance, calculated as the transpiration rate/delta psi between two points in the water transport pathway, was used to analyse water transport through the tube-soil-plant continuum. At porous tube water pressures of -0.5 to-1.5 kPa soil moisture was readily available and hydraulic conductance of the plant limited water transport. At -2.0 kPa, hydraulic conductance of the bulk soil was the dominant factor in water movement.

Response of the water status of soybean to changes in soil water potentials controlled by the water pressure in microporous tubes

NASA Technical Reports Server (NTRS)

Steinberg, S. L.; Henninger, D. L.

1997-01-01

Water transport through a microporous tube-soil-plant system was investigated by measuring the response of soil and plant water status to step change reductions in the water pressure within the tubes. Soybeans were germinated and grown in a porous ceramic 'soil' at a porous tube water pressure of -0.5 kpa for 28 d. During this time, the soil matric potential was nearly in equilibrium with tube water pressure. Water pressure in the porous tubes was then reduced to either -1.0, -1.5 or -2.0 kPa. Sap flow rates, leaf conductance and soil, root and leaf water potentials were measured before and after this change. A reduction in porous tube water pressure from -0.5 to -1.0 or -1.5 kPa did not result in any significant change in soil or plant water status. A reduction in porous tube water pressure to -2.0 kPa resulted in significant reductions in sap flow, leaf conductance, and soil, root and leaf water potentials. Hydraulic conductance, calculated as the transpiration rate/delta psi between two points in the water transport pathway, was used to analyse water transport through the tube-soil-plant continuum. At porous tube water pressures of -0.5 to-1.5 kPa soil moisture was readily available and hydraulic conductance of the plant limited water transport. At -2.0 kPa, hydraulic conductance of the bulk soil was the dominant factor in water movement.

Estimating the potential health impact and costs of implementing a local policy for food procurement to reduce the consumption of sodium in the county of Los Angeles.

PubMed

Gase, Lauren N; Kuo, Tony; Dunet, Diane; Schmidt, Steven M; Simon, Paul A; Fielding, Jonathan E

2011-08-01

We examined approaches to reduce sodium content of food served in settings operated or funded by the government of the County of Los Angeles, California. We adapted health impact assessment methods to mathematically simulate various levels of reduction in the sodium content of food served by the County of Los Angeles and to estimate the reductions' potential impacts on mean systolic blood pressure (SBP) among food-service customers. We used data provided by county government food-service vendors to generate these simulations. Our analysis predicted that if the postulated sodium-reduction strategies were implemented, adults would consume, on average, 233 fewer milligrams of sodium each day. This would correspond to an average decrease of 0.71 millimeters of mercury in SBP among adult hypertensives, 388 fewer cases of uncontrolled hypertension in the study population, and an annual decrease of $629,724 in direct health care costs. Our findings suggest that a food-procurement policy can contribute to positive health and economic effects at the local level. Our approach may serve as an example of sodium-reduction analysis for other jurisdictions to follow.

Blood-pressure targets in patients with recent lacunar stroke: the SPS3 randomised trial.

PubMed

Benavente, O R; Coffey, C S; Conwit, R; Hart, R G; McClure, L A; Pearce, L A; Pergola, P E; Szychowski, J M

2013-08-10

Lowering of blood pressure prevents stroke but optimum target levels to prevent recurrent stroke are unknown. We investigated the effects of different blood-pressure targets on the rate of recurrent stroke in patients with recent lacunar stroke. In this randomised open-label trial, eligible patients lived in North America, Latin America, and Spain and had recent, MRI-defined symptomatic lacunar infarctions. Patients were recruited between March, 2003, and April, 2011, and randomly assigned, according to a two-by-two multifactorial design, to a systolic-blood-pressure target of 130-149 mm Hg or less than 130 mm Hg. The primary endpoint was reduction in all stroke (including ischaemic strokes and intracranial haemorrhages). Analysis was done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT 00059306. 3020 enrolled patients, 1519 in the higher-target group and 1501 in the lower-target group, were followed up for a mean of 3·7 (SD 2·0) years. Mean age was 63 (SD 11) years. After 1 year, mean systolic blood pressure was 138 mm Hg (95% CI 137-139) in the higher-target group and 127 mm Hg (95% CI 126-128) in the lower-target group. Non-significant rate reductions were seen for all stroke (hazard ratio 0·81, 95% CI 0·64-1·03, p=0·08), disabling or fatal stroke (0·81, 0·53-1·23, p=0·32), and the composite outcome of myocardial infarction or vascular death (0·84, 0·68-1·04, p=0·32) with the lower target. The rate of intracerebral haemorrhage was reduced significantly (0·37, 0·15-0·95, p=0·03). Treatment-related serious adverse events were infrequent. Although the reduction in stroke was not significant, our results support that in patients with recent lacunar stroke, the use of a systolic-blood-pressure target of less than 130 mm Hg is likely to be beneficial. National Institutes of Health-National Institute of Neurological Disorders and Stroke (NIH-NINDS). Copyright © 2013 Elsevier Ltd. All rights reserved.

An Experimental Investigation of Unsteady Surface Pressure on an Airfoil in Turbulence

NASA Technical Reports Server (NTRS)

Mish, Patrick F.; Devenport, William J.

2003-01-01

Measurements of fluctuating surface pressure were made on a NACA 0015 airfoil immersed in grid generated turbulence. The airfoil model has a 2 ft chord and spans the 6 ft Virginia Tech Stability Wind Tunnel test section. Two grids were used to investigate the effects of turbulence length scale on the surface pressure response. A large grid which produced turbulence with an integral scale 13% of the chord and a smaller grid which produced turbulence with an integral scale 1.3% of the chord. Measurements were performed at angles of attack, alpha from 0 to 20 . An array of microphones mounted subsurface was used to measure the unsteady surface pressure. The goal of this measurement was to characterize the effects of angle of attack on the inviscid response. Lift spectra calculated from pressure measurements at each angle of attack revealed two distinct interaction regions; for omega(sub r) = omega b / U(sub infinity) is less than 10 a reduction in unsteady lift of up to 7 decibels (dB) occurs while an increase occurs for omega(sub r) is greater than 10 as the angle of attack is increased. The reduction in unsteady lift at low omega(sub r) with increasing angle of attack is a result that has never before been shown either experimentally or theoretically. The source of the reduction in lift spectral level appears to be closely related to the distortion of inflow turbulence based on analysis of surface pressure spanwise correlation length scales. Furthermore, while the distortion of the inflow appears to be critical in this experiment, this effect does not seem to be significant in larger integral scale (relative to the chord) flows based on the previous experimental work of McKeough suggesting the airfoils size relative to the inflow integral scale is critical in defining how the airfoil will respond under variation of angle of attack. A prediction scheme is developed that correctly accounts for the effects of distortion when the inflow integral scale is small relative to the airfoil chord. This scheme utilizes Rapid Distortion Theory to account for the distortion of the inflow with the distortion field modeled using a circular cylinder.

Surgical treatment reduces blood pressure in children with unilateral congenital hydronephrosis.

PubMed

Al-Mashhadi, Ammar; Nevéus, Tryggve; Stenberg, Arne; Karanikas, Birgitta; Persson, A Erik G; Carlström, Mattias; Wåhlin, Nils

2015-04-01

Renal disorders can cause hypertension, but less is known about the influence of hydronephrosis on blood pressure. Hydronephrosis due to pelvo-ureteric junction obstruction (PUJO) is a fairly common condition (incidence in newborns of 0.5-1%). Although hypertensive effects of hydronephrosis have been suggested, this has not been substantiated by prospective studies in humans [1-3]. Experimental studies with PUJO have shown that animals with induced hydronephrosis develop salt-sensitive hypertension, which strongly correlate to the degree of obstruction [4-7]. Moreover, relief of the obstruction normalized blood pressure [8]. In this first prospective study our aim was to study the blood pressure pattern in pediatric patients with hydronephrosis before and after surgical correction of the ureteral obstruction. Specifically, we investigated if preoperative blood pressure is reduced after surgery and if split renal function and renographic excretion curves provide any prognostic information. Twelve patients with unilateral congenital hydronephrosis were included in this prospective study. Ambulatory blood pressure (24 h) was measured preoperatively and six months after surgery. Preoperative evaluations of bilateral renal function by Tc99m-MAG3 scintigraphy, and renography curves, classified according to O'Reilly, were also performed. As shown in the summary figure, postoperative systolic (103 ± 2 mmHg) and diastolic (62 ± 2 mmHg) blood pressure were significantly lower than those obtained preoperatively (110 ± 4 and 69 ± 2 mmHg, respectively), whereas no changes in circadian variation or pulse pressure were observed. Renal functional share of the hydronephrotic kidney ranged from 11 to 55%. There was no correlation between the degree of renal function impairment and the preoperative excretory pattern, or between the preoperative excretory pattern and the blood pressure reduction postoperatively. However, preoperative MAG3 function of the affected kidney correlated with the magnitude of blood pressure change after surgery. Correction of the obstruction lowered blood pressure, and the reduction in blood pressure appeared to correlate with the degree of renal functional impairment, but not with the excretory pattern. Thus, in the setting of hypertension, it appears that the functional share of the hydronephrotic kidney should be considered an indicator of the need for surgery, whereas the renography curve is less reliable. The strength of the present study is the prospective nature and that ambulatory blood pressure monitoring was used. Future longitudinal prolonged follow-up studies are warranted to confirm the present findings, and to understand if a real nephrogenic hypertension with potential necessity of treatment will develop. This novel prospective study in patients with congenital hydronephrosis demonstrates a reduction in blood pressure following relief of the obstruction. Based on the present results, we propose that the blood pressure level should also be taken into account when deciding whether to correct hydronephrosis surgically or not. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Effects of blood pressure reduction in mild hypertension: a systematic review and meta-analysis.

PubMed

Sundström, Johan; Arima, Hisatomi; Jackson, Rod; Turnbull, Fiona; Rahimi, Kazem; Chalmers, John; Woodward, Mark; Neal, Bruce

2015-02-03

Effects of blood pressure reduction in persons with grade 1 hypertension are unclear. To investigate whether pharmacologic blood pressure reduction prevents cardiovascular events and deaths in persons with grade 1 hypertension. Trials included in the BPLTTC (Blood Pressure Lowering Treatment Trialists' Collaboration) and trials identified from a previous review and electronic database searches. Patients without cardiovascular disease with blood pressures in the grade 1 hypertension range (140 to 159/90 to 99 mm Hg) who were randomly assigned to an active (antihypertensive drug or more intensive regimen) or control (placebo or less intensive regimen) blood pressure-lowering regimen. Individual-patient data from BPLTTC trials and aggregate data from other trials were extracted. Risk of bias was assessed for all trials. Individual-patient data involved 10 comparisons from trials where most patients had diabetes, and aggregate data involved 3 comparisons from trials of patients without diabetes. The average blood pressure reduction was about 3.6/2.4 mm Hg. Over 5 years, odds ratios were 0.86 (95% CI, 0.74 to 1.01) for total cardiovascular events, 0.72 (CI, 0.55 to 0.94) for strokes, 0.91 (CI, 0.74 to 1.12) for coronary events, 0.80 (CI, 0.57 to 1.12) for heart failure, 0.75 (CI, 0.57 to 0.98) for cardiovascular deaths, and 0.78 (CI, 0.67 to 0.92) for total deaths. Results were similar in secondary analyses. Withdrawal from treatment due to adverse effects was more common in the active groups. Blood pressure reductions and numbers of events were small. Blood pressure-lowering therapy is likely to prevent stroke and death in patients with uncomplicated grade 1 hypertension. Swedish Heart-Lung Foundation, Swedish Research Council, Australian Research Council, and National Health and Medical Research Council of Australia.

The influence of recovery posture on post-exercise hypotension in normotensive men.

PubMed

Raine, N M; Cable, N T; George, K P; Campbell, I G

2001-03-01

Postexercise hypotension may be the result of an impaired vasoconstrictor response. This hypothesis was investigated by examining the central and peripheral hemodynamic responses during supine and seated recovery after maximal upright exercise. After supine or seated baseline measurements, seven normotensive male volunteers completed a graded upright cycling protocol to volitional exhaustion. This was immediately followed by either supine or seated recovery. Measurements of pulsatile arterial blood pressure and central and peripheral hemodynamic variables recorded 30 min before exercise were compared with those taken throughout 60 min of recovery. Compared with baseline, mean arterial pressure (MAP) was reduced after exercise (P < 0.05) although the degree of change was not different between the supine (-9 +/- 4 mm Hg) and seated positions (-6 +/- 2 mm Hg). This change in MAP was associated with a reduction in diastolic blood pressure (DBP) (P < 0.05) and arterial pulse pressure (APP) (P < 0.01) for the supine and seated positions, respectively. The reduction in APP during seated recovery was accompanied by a decline in stroke volume (SV) (P < 0.05), not seen in the supine position, that limited the contribution of cardiac output (CO) to the maintenance of MAP. This effect of seated recovery was compensated by greater systemic (SVR) and regional vascular resistances in the forearm (FVR) and the forearm skin (SkVRA). There was also evidence of an augmented return of FVR and SkVRA to resting levels in the seated position after exercise. The lower peripheral resistance in the supine compared with seated recovery position suggests there is potential for greater vasoconstriction, although this is not evoked to increase blood pressure. This further suggests that the arterial baroreceptor reflex is reset to a lower operating pressure after exercise.

[Forefoot relief with shoe inserts : Effects of different construction strategies].

PubMed

Baur, H; Merz, N; Muster, A; Flückiger, G; Hirschmüller, A

2018-04-01

Shoe inserts and shoe modifications are used to reduce plantar peak pressure. The effects of different shoe inserts and shoe construction strategies for relief of the forefoot have not yet been sufficiently evaluated. The aim of this study was to analyze the effects of shoe inserts and shoe construction strategies (e.g. metatarsal pad, forefoot cushioning and control) and shoe modifications (e.g. flexible or stiff) on the peak plantar pressure in the forefoot region. In this study 15 healthy subjects were recruited. Plantar pressure distribution was measured using an in-shoe system during walking (3.5km∙h -1 ) on a treadmill and the average plantar peak pressure (kPa) in the forefoot was calculated. The statistics for testing the hypothesis were carried out using 2‑factorial ANOVA with repeat measurements (factors: shoe, insert; α = 0.05). The metatarsal pad and forefoot cushioning led to a reduction of peak pressure, which was statistically significant compared to the control condition (p = 0.009). No differences were observed between both shoe inserts (p > 0.05). A comparison between stiff and flexible shoes revealed a statistically significant pressure reduction in favor of stiff shoes (p = 0.0001). The metatarsal pad led to a peak pressure increase in the midfoot of 12% and by 21% compared to control and forefoot cushioning, respectively. A peak pressure reduction in the forefoot can be achieved with a metatarsal pad or with cushioning; however, the metatarsal pad resulted in a subsequent increase in midfoot pressure. Moreover, shoe construction is crucial because a stiff shoe contributes to a better peak pressure reduction compared to a flexible shoe. Prospective clinical studies should be carried out to prove whether this results in beneficial effects for patients with metatarsalgia.

[Metformin and changes in blood pressure and heart rate in lean patients with polycystic ovary syndrome (PCOS)--preliminary study].

PubMed

Tomczyk, Rita; Ociepka, Agnieszka; Kiałka, Marta; Milewicz, Tomasz; Migacz, Kamila; Kowalczuk, Aleksandra; Klocek, Marek

2015-01-01

The aim of our study was to assess the value of blood pressure and heart rate using the 24-hour blood pressure monitoring (ABPM) before and after treatment with metformin to patients with polycystic ovary syndrome (PCOS) and normal lean. 5 patients received metformin 1500 mg per day in three divided doses. ABPM was performed to each patient with PCOS twice: before and after 6 months of treatment with metformin. In patients with PCOS and normal lean after treatment with metformin we observed: statistically significant lower systolic blood pressure (120.2 ± 22.33 mmHg vs 113.22 ± 21.43 mm Hg, p = 0.0248); lower systolic blood pressure of daily measurements (127.1 ± 32.13 mmHg vs 116.1 ± 22.08 mmHg, p = 0.0062); reduction in average arterial pressure MAP in the measurement of the day (95.52 ± 22.76 mmHg vs 88.36 ± 16.41 mmHg, p = 0.048); oscillometric pressure reduction (96.27 ± 27.93 mmHg vs 87.82 ± 21.61, p = 0.0004 mmHg); oscillometric pressure reduction of daily measurements (102.1 ± 27.93 mmHg vs 91.85 ± 21.61 mmHg, p = 0.0032); oscillometric pressure reduction in the measure- ment of the night (88.81 ± 24.85 mmHg vs 82.22 ± 20.54 mmHg, p = 0.0089). In women after treatment with metformin has also been observed higher average heart rate (65.82 ± 13.48 / min vs. 70.71 ± 16.04 min; p < 0.01). The calculations included 500 measurements. Treatment with metformin in patients with PCOS and normal lean leads to lower blood pressure and increases the frequency of heart rate.

Experimental investigation of the noise reduction of supersonic exhaust jets with fluidic inserts

NASA Astrophysics Data System (ADS)

Powers, Russell William Walter

The noise produced by the supersonic, high temperature jets that exhaust from military aircraft is becoming a hazard to naval personnel and a disturbance to communities near military bases. Methods to reduce the noise produced from these jets in a practical full-scale environment are difficult. The development and analysis of distributed nozzle blowing for the reduction of radiated noise from supersonic jets is described. Model scale experiments of jets that simulate the exhaust jets from typical low-bypass ratio military jet aircraft engines during takeoff are performed. Fluidic inserts are created that use distributed blowing in the divergent section of the nozzle to simulate mechanical, hardwall corrugations, while having the advantage of being an active control method. This research focuses on model scale experiments to better understand the fluidic insert noise reduction method. Distributed blowing within the divergent section of the military-style convergent divergent nozzle alters the shock structure of the jet in addition to creating streamwise vorticity for the reduction of mixing noise. Enhancements to the fluidic insert design have been performed along with experiments over a large number of injection parameters and core jet conditions. Primarily military-style round nozzles have been used, with preliminary measurements of hardwall corrugations and fluidic inserts in rectangular nozzle geometries also performed. It has been shown that the noise reduction of the fluidic inserts is most heavily dependent upon the momentum flux ratio between the injector and core jet. Maximum reductions of approximately 5.5 dB OASPL have been observed with practical mass flow rates and injection pressures. The first measurements with fluidic inserts in the presence of a forward flight stream have been performed. Optimal noise reduction occurs at similar injector parameters in the presence of forward flight. Fluidic inserts in the presence of a forward flight stream were observed to reduce the peak mixing noise below the already reduced levels by nearly 4 dB OASP and the broadband shock-associated noise by nearly 3 dB OASP. Unsteady velocity measurements are used to complement acoustic results of jets with fluidic inserts. Measured axial turbulence intensities and mean axial velocity are examined to illuminate the differences in the flow field from jets with fluidic inserts. Comparisons of laser Doppler measurements with RANS CFD simulations are shown with good agreement. Analysis of the effect of spatial turbulence on the measured quantities is performed. Experimental model scale measurements of jets with and without fluidic inserts over a simulated carrier deck are presented. The model carrier environment consists of a ground plane of adjustable distance below the jet, and a simulated jet blast deflector similar to those found in practice. Measurements are performed with far-field microphones, near-field microphones, and unsteady pressure sensors. The constructive and destructive interference that results from the interaction of the direct and reflected sound waves is observed and compared with results from free jets. The noise reduction of fluidic inserts in a realistic carrier deck environment with steering of the "quiet planes" is examined. The overall sound pressure level in heat-simulated jets is reduced by 3-5 dB depending on the specific angle and ground plane height. Jets impinging upon a modeled jet blast deflector are tested in addition to jets solely in the presence of the carrier deck. Observed modifications to the acoustic field from the presence of the jet blast deflector include downstream acoustic shielding and low frequency augmentation. The region of maximum noise radiation for heat-simulated jets from nozzles with fluidic inserts impinging on the jet blast deflector is reduced in overall sound pressure level by 4-7 dB. This region includes areas where aircraft carrier personnel are located. iv.

Supersonic turbulent boundary layers with periodic mechanical non-equilibrium

NASA Astrophysics Data System (ADS)

Ekoto, Isaac Wesley

Previous studies have shown that favorable pressure gradients reduce the turbulence levels and length scales in supersonic flow. Wall roughness has been shown to reduce the large-scales in wall bounded flow. Based on these previous observations new questions have been raised. The fundamental questions this dissertation addressed are: (1) What are the effects of wall topology with sharp versus blunt leading edges? and (2) Is it possible that a further reduction of turbulent scales can occur if surface roughness and favorable pressure gradients are combined? To answer these questions and to enhance the current experimental database, an experimental analysis was performed to provide high fidelity documentation of the mean and turbulent flow properties along with surface and flow visualizations of a high-speed (M = 2.86), high Reynolds number (Retheta ≈ 60,000) supersonic turbulent boundary layer distorted by curvature-induced favorable pressure gradients and large-scale ( k+s ≈ 300) uniform surface roughness. Nine models were tested at three separate locations. Three pressure gradient models strengths (a nominally zero, a weak, and a strong favorable pressure gradient) and three roughness topologies (aerodynamically smooth, square, and diamond shaped roughness elements) were used. Highly resolved planar measurements of mean and fluctuating velocity components were accomplished using particle image velocimetry. Stagnation pressure profiles were acquired with a traversing Pitot probe. Surface pressure distributions were characterized using pressure sensitive paint. Finally flow visualization was accomplished using schlieren photographs. Roughness topology had a significant effect on the boundary layer mean and turbulent properties due to shock boundary layer interactions. Favorable pressure gradients had the expected stabilizing effect on turbulent properties, but the improvements were less significant for models with surface roughness near the wall due to increased tendency towards flow separation. It was documented that proper roughness selection coupled with a sufficiently strong favorable pressure gradient produced regions of "negative" production in the transport of turbulent stress. This led to localized areas of significant turbulence stress reduction. With proper roughness selection and sufficient favorable pressure gradient strength, it is believed that localized relaminarization of the boundary layer is possible.

What Is High Blood Pressure Medicine?

MedlinePlus

ANSWERS by heart Lifestyle + Risk Reduction High Blood Pressure What Is High Blood Pressure Medicine? Your doctor has prescribed medicine to help lower your blood pressure. You also need to make the ...

African Americans and High Blood Pressure

MedlinePlus

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) ...

In-flight acoustic measurements on a light twin-engined turboprop airplane

NASA Technical Reports Server (NTRS)

Wilby, J. F.; Mcdaniel, C. D.; Wilby, E. G.

1985-01-01

Four series of flight tests were conducted to measure sound pressure levels inside and outside the cabin of a twin-engined turboprop airplane. Particular emphasis was placed on harmonics of the propeller blade passage frequency. The cabin was unfurnished for the first three flights, when the main objective was to investigate the repeatability of the data. For the fourth flight, the cabin was treated with fiberglass batts. Typically, the exterior sound pressure levels were found to vary 3 to 5 dB for a given harmonic, but variations as high as 8 dB were observed. The variability of harmonic levels within the cabin was slightly higher but depended on control of the relative phase between the propellers; when phase was not controlled the average variability was about 10 dB. Noise reductions provided by the fuselage structure were in the range of 20 to 40 dB, when an exterior microphone in the plane of rotation of the propeller was used as reference.

Pressure dependence of the oxygen reduction reaction at the platinum microelectrode/nafion interface - Electrode kinetics and mass transport

NASA Technical Reports Server (NTRS)

Parthasarathy, Arvind; Srinivasan, Supramaniam; Appleby, A. J.; Martin, Charles R.

1992-01-01

The investigation of oxygen reduction kinetics at the platinum/Nafion interface is of great importance in the advancement of proton-exchange-membrane (PEM) fuel-cell technology. This study focuses on the dependence of the oxygen reduction kinetics on oxygen pressure. Conventional Tafel analysis of the data shows that the reaction order with respect to oxygen is unity at both high and low current densities. Chronoamperometric measurements of the transport parameters for oxygen in Nafion show that oxygen dissolution follows Henry's isotherm. The diffusion coefficient of oxygen is invariant with pressure; however, the diffusion coefficient for oxygen is lower when air is used as the equilibrating gas as compared to when oxygen is used for equilibration. These results are of value in understanding the influence of O2 partial pressure on the performance of PEM fuel cells and also in elucidating the mechanism of oxygen reduction at the platinum/Nafion interface.

Effects of electrical stimulation-induced gluteal versus gluteal and hamstring muscles activation on sitting pressure distribution in persons with a spinal cord injury.

PubMed

Smit, C A J; Haverkamp, G L G; de Groot, S; Stolwijk-Swuste, J M; Janssen, T W J

2012-08-01

Ten participants underwent two electrical stimulation (ES) protocols applied using a custom-made electrode garment with built-in electrodes. Interface pressure was measured using a force-sensitive area. In one protocol, both the gluteal and hamstring (g+h) muscles were activated, in the other gluteal (g) muscles only. To study and compare the effects of electrically induced activation of g+h muscles versus g muscles only on sitting pressure distribution in individuals with a spinal cord injury (SCI). Ischial tuberosities interface pressure (ITs pressure) and pressure gradient. In all participants, both protocols of g and g+h ES-induced activation caused a significant decrease in IT pressure. IT pressure after g+h muscles activation was reduced significantly by 34.5% compared with rest pressure, whereas a significant reduction of 10.2% after activation of g muscles only was found. Pressure gradient reduced significantly only after stimulation of g+h muscles (49.3%). g+h muscles activation showed a decrease in pressure relief (Δ IT) over time compared with g muscles only. Both protocols of surface ES-induced of g and g+h activation gave pressure relief from the ITs. Activation of both g+h muscles in SCI resulted in better IT pressure reduction in sitting individuals with a SCI than activation of g muscles only. ES might be a promising method in preventing pressure ulcers (PUs) on the ITs in people with SCI. Further research needs to show which pressure reduction is sufficient in preventing PUs.

Atorvastatin May Correct Dyslipidemia in Adult Patients at Risk for Alzheimer's Disease Through an Anti-Inflammatory Pathway.

PubMed

Zhao, Liandong; Zhao, Qitao; Zhou, Yong; Zhao, Ying; Wan, Qi

2016-01-01

Dyslipidemia is a risk factor for the pathogenesis of Alzheimer's disease. Although, atorvastatin is a well-accepted lipid-lowering agent, the benefits of atorvastatin treatment through an anti-inflammatory mechanism are still unclear. The present study was designed to examine changes in inflammatory markers following administration of atorvastatin in dyslipidemic patients with a parental history of Alzheimer's disease. Dyslipidemic adults with a parental history of Alzheimer's disease were administered either 40 mg of atorvastatin or placebo for 18 months. Before and after the study, lpid levels, blood pressure, body weight and body mass index, and the inflammatory markers hs-Creactive protein, serum monocyte chemoattractant protien-1, interleukin-1β, interleukin-6, and tumor necrosis factor-α were tested. Baseline levels of lipids, body mass index, hs-Creactive protein, monocyte chemoattractant protien-1, interleukin- 1β, interleukin-6 and tumor necrosis factor-α did not show any difference between the two groups. However, after 18 months of atorvastatin treatment, all inflammatory markers significantly decreased in association with a reduction of lipid profiles, body mass index, bodyweight, and blood pressure, compared with those patients treated with placebo. Administration of atorvastatin corrected dyslipidemia in association with a reduction in inflammatory markers. Our results suggest that the therapeutic benefits of atorvastatin possibly involve an anti-inflammatory pathway.

Measurements of Infrared and Acoustic Source Distributions in Jet Plumes

NASA Technical Reports Server (NTRS)

Agboola, Femi A.; Bridges, James; Saiyed, Naseem

2004-01-01

The aim of this investigation was to use the linear phased array (LPA) microphones and infrared (IR) imaging to study the effects of advanced nozzle-mixing techniques on jet noise reduction. Several full-scale engine nozzles were tested at varying power cycles with the linear phased array setup parallel to the jet axis. The array consisted of 16 sparsely distributed microphones. The phased array microphone measurements were taken at a distance of 51.0 ft (15.5 m) from the jet axis, and the results were used to obtain relative overall sound pressure levels from one nozzle design to the other. The IR imaging system was used to acquire real-time dynamic thermal patterns of the exhaust jet from the nozzles tested. The IR camera measured the IR radiation from the nozzle exit to a distance of six fan diameters (X/D(sub FAN) = 6), along the jet plume axis. The images confirmed the expected jet plume mixing intensity, and the phased array results showed the differences in sound pressure level with respect to nozzle configurations. The results show the effects of changes in configurations to the exit nozzles on both the flows mixing patterns and radiant energy dissipation patterns. By comparing the results from these two measurements, a relationship between noise reduction and core/bypass flow mixing is demonstrated.

Energy Efficient High-Pressure Turbine Leakage Technology Report

NASA Technical Reports Server (NTRS)

Gardner, W. B.

1980-01-01

The leakage test program was one of such supporting technology programs structured to provide guidance to the Energy Efficient Engine High Pressure Turbine Component Design Effort. Leakage reduction techniques were identified and evaluated. Test models were used to simulate component leak paths and to evaluate leakage reduction techniques. These models simulated the blade/disk attachment, the vane inner platform attachment, and the vane outer platform attachment combined with the blade outer airseal. Disk blade attachment testing indicated that leakage in this area could be reduced to very low levels by paying careful attention to the tolerances along the contact surface between the blade vibration damper and the blade platform contact surface. The aim of feather seal testing was to achieve a goal for an effective leakage gap of one mil (.001 inch) per inch of feather seal length. Results indicated that effective gaps even below the goal level were achievable by (1) maintaining close tolerances between feather seals and their slots to minimize end gaps and limit seal rotation, (2) avoiding feather seal overlap, and (3) minimizing feather seal intersections. W seals were shown to be effective leakage control devices. Wire rope, in its present state of development, was shown not to be an effective sealing concept for application to the component design.

Effects of canola and high-oleic-acid canola oils on abdominal fat mass in individuals with central obesity.

PubMed

Liu, Xiaoran; Kris-Etherton, Penny M; West, Sheila G; Lamarche, Benoît; Jenkins, David J A; Fleming, Jennifer A; McCrea, Cindy E; Pu, Shuaihua; Couture, Patrick; Connelly, Philip W; Jones, Peter J H

2016-11-01

To determine the effect of diets low in saturated fatty acids and high in monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids on body composition in participants at risk for metabolic syndrome (MetS). This study was a randomized, crossover, controlled feeding study. Participants (n = 101, ages 49.5 ± 1.2, BMI 29.4 ± 0.4 kg/m 2 ) were randomized to five isocaloric diets containing treatment oils: Canola, CanolaOleic, CanolaDHA, Corn/Safflower, and Flax/Safflower. Each diet period was 4 weeks followed by a 2- to 4-week washout period. Canola (3.1 kg, P = 0.026) and CanolaOleic oil diets (3.09 kg, P = 0.03) reduced android fat mass compared with the Flax/Saff oil diet (3.2 kg), particularly in men. The decrease in abdominal fat mass was correlated with the reduction in blood pressure after the Canola (systolic blood pressure: r = 0.26, P = 0.062; diastolic blood pressure: r = 0.38, P = 0.0049) and CanolaOleic oil diets (systolic blood pressure: r = 0.39 P = 0.004; diastolic blood pressure: r = 0.45, P = 0.0006). The decrease in abdominal fat mass also was associated with a reduction in triglyceride levels after the CanolaOleic oil diet (r = 0.42, P = 0.002). Diets high in MUFA (compared with PUFA) reduced central obesity with an accompanying improvement in MetS risk factors. Diets high in MUFA may be beneficial for treating and perhaps preventing MetS. © 2016 The Obesity Society.

An improved source model for aircraft interior noise studies

NASA Technical Reports Server (NTRS)

Mahan, J. R.; Fuller, C. R.

1985-01-01

There is concern that advanced turboprop engines currently being developed may produce excessive aircraft cabin noise levels. This concern has stimulated renewed interest in developing aircraft interior noise reduction methods that do not significantly increase take off weight. An existing analytical model for noise transmission into aircraft cabins was utilized to investigate the behavior of an improved propeller source model for use in aircraft interior noise studies. The new source model, a virtually rotating dipole, is shown to adequately match measured fuselage sound pressure distributions, including the correct phase relationships, for published data. The virtually rotating dipole is used to study the sensitivity of synchrophasing effectiveness to the fuselage sound pressure trace velocity distribution. Results of calculations are presented which reveal the importance of correctly modeling the surface pressure phase relations in synchrophasing and other aircraft interior noise studies.

An improved source model for aircraft interior noise studies

NASA Technical Reports Server (NTRS)

Mahan, J. R.; Fuller, C. R.

1985-01-01

There is concern that advanced turboprop engines currently being developed may produce excessive aircraft cabin noise level. This concern has stimulated renewed interest in developing aircraft interior noise reduction methods that do not significnatly increase take off weight. An existing analytical model for noise transmission into aircraft cabins was utilized to investigate the behavior of an improved propeller source model for use in aircraft interior noise studies. The new source model, a virtually rotating dipole, is shown to adequately match measured fuselage sound pressure distributions, including the correct phase relationships, for published data. The virtually rotating dipole is used to study the sensitivity of synchrophasing effectiveness to the fuselage sound pressure trace velocity distribution. Results of calculations are presented which reveal the importance of correctly modeling the surface pressure phase relations in synchrophasing and other aircraft interior noise studies.

Pressure dependence of effective Coulomb interaction parameters in BaFe2As2 by first-principle calculation

NASA Astrophysics Data System (ADS)

Aghajani, M.; Hadipour, H.; Akhavan, M.

2018-05-01

Pressure dependence of the onsite Coulomb interactions of the BaFe2As2 has been studied by employing the constrained random phase approximation within first-principle calculations. Analyzing total and projected density of states, a pseudogap is found for dxy band at the energy roughly 0.25 eV higher than the Fermi level. Also, by applying pressure the spectral weight of the dxy orbital vanishes while other orbitals remain metallic. The different screening channels, as discussed in four different models, affect significantly on the Hubbard U while the Hund J remains almost unchanged. The average onsite bare and partially and fully screened Coulomb interactions increase with different rates upon compression. These different rates can be explained by competition between the electronic screening and reduction of bond lengths.

Effects of High-Hydrostatic Pressure on Inactivation of Human Norovirus and Physical and Sensory Characteristics of Oysters.

PubMed

Ye, Mu; Lingham, Talaysha; Huang, Yaoxin; Ozbay, Gulnihal; Ji, Lin; Karwe, Mukund; Chen, Haiqiang

2015-06-01

The purpose of the study was to determine the effect of high-hydrostatic pressure (HHP) on inactivation of human norovirus (HuNoV) in oysters and to evaluate organoleptic characteristics of oysters treated at pressure levels required for HuNoV inactivation. Genogroup I.1 (GI.1) or Genogroup II.4 (GII.4) HuNoV was inoculated into oysters and treated at 300 to 600 MPa at 25 and 0 °C for 2 min. After HHP, viral particles were extracted by porcine gastric mucin-conjugated magnetic beads (PGM-MBs) and viral RNA was quantified by real-time RT-PCR. Lower initial temperature (0 °C) significantly enhanced HHP inactivation of HuNoV compared to ambient temperature (25 °C; P < 0.05). HHP at 350 and 500 MPa at 0 °C could achieve more than 4 log10 reduction of GII.4 and GI.1 HuNoV in oysters, respectively. HHP treatments did not significantly change color or texture of oyster tissue. A 1- to 5-scale hedonic sensory evaluation on appearance, aroma, color, and overall acceptability showed that pressure-treated oysters received significantly higher quality scores than the untreated control (P < 0.05). Elevated pressure levels at 450 and 500 MPa did not significantly affect scores compared to 300 MPa at 0 °C, indicating increasing pressure level did not affect sensory acceptability of oysters. Oysters treated at 0 °C had slightly lower acceptability than the group treated at room temperature on day 1 (P < 0.05), but after 1 wk storage, no significant difference in sensory attributes and consumer desirability was observed (P > 0.05). © 2015 Institute of Food Technologists®

Effects of acoustic treatment on the interior noise levels of a twin-engine propeller aircraft - Experimental flight results and theoretical predictions

NASA Technical Reports Server (NTRS)

Beyer, T. B.; Powell, C. A.; Daniels, E. F.; Pope, L. D.

1984-01-01

In-flight noise level measurements were made within two cabin configurations of a general aviation business aircraft. The Fairchild Merlin IVC twin-engine aircraft was tested with bare walls and fiberglass insulation and in an executive trim configuration. Narrow-band and octave format data were subjected to analyses which permitted identification of the blade passage harmonics (BPH). Cabin noise level reductions (insertion losses) due to added insulation varied with position in the cabin, the BPH number, cabin pressure, and engine torque. The measurements were closely predicted using the propeller aircraft interior noise (PAIN) mode.

Potassium and Health123

PubMed Central

Weaver, Connie M.

2013-01-01

Potassium was identified as a shortfall nutrient by the Dietary Guidelines for Americans 2010 Advisory Committee. The committee concluded that there was a moderate body of evidence of the association between potassium intake and blood pressure reduction in adults, which in turn influences the risk of stroke and coronary heart disease. Evidence is also accumulating of the protective effect of adequate dietary potassium on age-related bone loss and reduction of kidney stones. These benefits depend on organic anions associated with potassium as occurs in foods such as fruits and vegetables, in contrast to similar blood pressure-lowering benefits of potassium chloride. Benefits to blood pressure and bone health may occur at levels below current recommendations for potassium intake, especially from diet, but dose-response trials are needed to confirm this. Nevertheless, intakes considerably above current levels are needed for optimal health, and studies evaluating small increases in fruit and vegetable intake on bone and heart outcomes for short periods have had disappointing results. In modern societies, Western diets have led to a decrease in potassium intake with reduced consumption of fruits and vegetables with a concomitant increase in sodium consumption through increased consumption of processed foods. Consumption of white vegetables is associated with decreased risk of stroke, possibly related to their high potassium content. Potatoes are the highest source of dietary potassium, but the addition of salt should be limited. Low potassium-to-sodium intake ratios are more strongly related to cardiovascular disease risk than either nutrient alone. This relationship deserves further attention for multiple target tissue endpoints. PMID:23674806

Effects of topical anaesthetics and repeated tonometry on intraocular pressure.

PubMed

Jóhannesson, Gauti; Hallberg, Per; Eklund, Anders; Behndig, Anders; Lindén, Christina

2014-03-01

To investigate the effects of repeated measurements of intraocular pressure (IOP) using Goldmann applanation tonometry (GAT) and applanation resonance tonometry (ART) to identify mechanisms contributing to the expected IOP reduction. A prospective, single-centre study with six healthy volunteers. Consecutive repeated series (six measurements/serie/method) were made alternately on both eyes for 1 hr with oxybuprocaine/fluorescein in the right eye and tetracaine in the left. The left eye was Pentacam(®) photographed before and repeatedly for 20 min after the IOP measurements. On a separate occasion, the same volunteers received the same amount of anaesthetic drops for 1 hr but without repeated IOP measurements. A significant IOP reduction occurred with both ART and GAT in the oxybuprocaine-treated eye, -4.4 mmHg and -3.8 mmHg, respectively and with ART in the tetracaine eye, -2.1 mmHg. There was a significant difference in IOP reduction between the oxybuprocaine and tetracaine eyes with ART. There was a significant drop in anterior chamber volume (ACV) immediately after the IOP measurements, -12.6 μl that returned to pretrial level after 2 min. After 1 hr of receiving anaesthetic eye drops (without IOP measurements), the IOP decreased significantly in the oxybuprocaine eye for both ART and GAT, -3.1 and -1.7 mmHg, respectively, but not in the tetracaine eye (p = 0.72). The IOP reduction cannot be explained solely by aqueous humor being pressed out of the anterior chamber. While significant IOP reduction occurred with both tetracaine and oxybuprocaine after repeated mechanical applanation, the IOP reduction was significantly greater with oxybuprocaine. © 2013 The Authors. Acta Ophthalmologica © 2013 Acta Ophthalmologica Scandinavica Foundation.

Identification of the inactivating factors and mechanisms exerted on MS2 coliphage in concentrated synthetic urine.

PubMed

Oishi, Wakana; Sano, Daisuke; Decrey, Loic; Kadoya, Syunsuke; Kohn, Tamar; Funamizu, Naoyuki

2017-11-15

Volume reduction (condensation) is a key for the practical usage of human urine as a fertilizer because it enables the saving of storage space and the reduction of transportation cost. However, concentrated urine may carry infectious disease risks resulting from human pathogens frequently present in excreta, though the survival of pathogens in concentrated urine is not well understood. In this study, the inactivation of MS2 coliphage, a surrogate for single-stranded RNA human enteric viruses, in concentrated synthetic urine was investigated. The infectious titer reduction of MS2 coliphage in synthetic urine samples was measured by plaque assay, and the reduction of genome copy number was monitored by reverse transcription-quantitative PCR (RTqPCR). Among chemical-physical conditions such as pH and osmotic pressure, uncharged ammonia was shown to be the predominant factor responsible for MS2 inactivation, independently of urine concentration level. The reduction rate of the viral genome number varied among genome regions, but the comprehensive reduction rate of six genome regions was well correlated with that of the infectious titer of MS2 coliphage. This indicates that genome degradation is the main mechanism driving loss of infectivity, and that RT-qPCR targeting the six genome regions can be used as a culture-independent assay for monitoring infectivity loss of the coliphage in urine. MS2 inactivation rate constants were well predicted by a model using ion composition and speciation in synthetic urine samples, which suggests that MS2 infectivity loss can be estimated solely based on the solution composition, temperature and pH, without explicitly accounting for effects of osmotic pressure. Copyright © 2017 Elsevier B.V. All rights reserved.

A LARGE-SCALE CLUSTER RANDOMIZED TRIAL TO DETERMINE THE EFFECTS OF COMMUNITY-BASED DIETARY SODIUM REDUCTION – THE CHINA RURAL HEALTH INITIATIVE SODIUM REDUCTION STUDY

PubMed Central

Li, Nicole; Yan, Lijing L.; Niu, Wenyi; Labarthe, Darwin; Feng, Xiangxian; Shi, Jingpu; Zhang, Jianxin; Zhang, Ruijuan; Zhang, Yuhong; Chu, Hongling; Neiman, Andrea; Engelgau, Michael; Elliott, Paul; Wu, Yangfeng; Neal, Bruce

2013-01-01

Background Cardiovascular diseases are the leading cause of death and disability in China. High blood pressure caused by excess intake of dietary sodium is widespread and an effective sodium reduction program has potential to improve cardiovascular health. Design This study is a large-scale, cluster-randomized, trial done in five Northern Chinese provinces. Two counties have been selected from each province and 12 townships in each county making a total of 120 clusters. Within each township one village has been selected for participation with 1:1 randomization stratified by county. The sodium reduction intervention comprises community health education and a food supply strategy based upon providing access to salt substitute. Subsidization of the price of salt substitute was done in 30 intervention villages selected at random. Control villages continued usual practices. The primary outcome for the study is dietary sodium intake level estimated from assays of 24 hour urine. Trial status The trial recruited and randomized 120 townships in April 2011. The sodium reduction program was commenced in the 60 intervention villages between May and June of that year with outcome surveys scheduled for October to December 2012. Baseline data collection shows that randomisation achieved good balance across groups. Discussion The establishment of the China Rural Health Initiative has enabled the launch of this large-scale trial designed to identify a novel, scalable strategy for reduction of dietary sodium and control of blood pressure. If proved effective, the intervention could plausibly be implemented at low cost in large parts of China and other countries worldwide. PMID:24176436

The effect of music on preprocedure anxiety in Hong Kong Chinese day patients.

PubMed

Lee, David; Henderson, Amanda; Shum, David

2004-03-01

To identify the effect of music on preprocedure anxiety levels of Hong Kong Chinese patients undergoing day procedures in a local community based hospital. Pre and post-test quasi experimental design with non-random assignment. A total of 113 participants were assigned to the control group or intervention group depending on the day of their procedure. Participants' anxiety levels were measured objectively by comparing their vital signs and subjectively by the Spielberger State Trait Anxiety Scale. Participants' physiological parameters (blood pressure, pulse and respiration) and State Trait Anxiety Scale were measured at two time periods. The control group undertook the usual relaxing activities provided in the waiting room compared with the intervention group who listened to music of their own choice in reclining chairs while waiting for the procedure. The physiological parameters for both the control and intervention groups dropped significantly during the waiting period, however, only the intervention group had a significant reduction in reported anxiety levels. These results suggest that providing self-selected music to day procedure patients in the preprocedure period assists in the reduction of physiological parameters and anxiety, yet, a relaxing environment can assist in the reduction of physiological parameters. The administration of self-selected music to day procedure patients in the preprocedure period can be effective in the reduction of physiological parameters and anxiety.

Role of GABAergic neurones in the nucleus tractus solitarii in modulation of cardiovascular activity.

PubMed

Zubcevic, Jasenka; Potts, Jeffrey T

2010-09-01

GABAergic neurones are interspersed throughout the nucleus tractus solitarii (NTS), and their tonic activity is crucial to the maintenance of cardiorespiratory homeostasis. However, the mechanisms that regulate the magnitude of GABAergic inhibition in the NTS remain unknown. We hypothesized that the level of GABAergic inhibition is proportionally regulated by the level of excitatory synaptic input to the NTS from baroreceptors. Using the in situ working heart-brainstem preparation in normotensive and spontaneously hypertensive rats, we blocked GABA(A) receptor-mediated neurotransmission in the NTS with gabazine (a specific GABA(A) receptor antagonist) at two levels of perfusion pressure (low PP, 60-70 mmHg; and high PP, 105-125 mmHg) while monitoring the immediate changes in cardiorespiratory variables. In normotensive rats, gabazine produced an immediate bradycardia consistent with disinhibition of NTS circuit neurones that regulate heart rate (HR) which was proportional to the level of arterial pressure (HR at low PP, 57 +/- 9 beats min(1); at high PP, 177 +/- 9 beats min(1); P < 0.001), suggesting that GABAergic circuitry in the NTS modulating heart rate was arterial pressure dependent. In contrast, there was no significant difference in the magnitude of gabazine-induced bradycardia in spontaneously hypertensive rats at low or high PP (HR at low PP, 45 +/- 10 beats min(1); at high PP, 58 +/- 7 beats min(1)). With regard to thoracic sympathetic nerve activity (tSNA), at high PP there was a significant reduction in tSNA during the inspiratory (I) phase of the respiratory cycle, but only in the normotensive rat (tSNA = 18.7 +/- 10%). At low PP, gabazine caused an elevation of the postinspiration phase of tSNA in both normotensive (tSNA = 23.7 +/- 2.9%) and hypertensive rats (tSNA = 44.2 +/- 14%). At low PP, gabazine produced no change in tSNA during the mid-expiration phase in either rat strain, but at high PP we observed a significant reduction in the mid-expiration phase tSNA, but only in the spontaneously hypertensive rat (tSNA = 25.2 +/- 8%). Gabazine at both low and high PP produced a reduction in the late expiration phase of tSNA in the hypertensive rat (low PP, tSNA = 29.4 +/- 4.4%; high PP, tSNA = 22.8 +/- 3%), whereas in the normotensive rat this was only significant at high PP (tSNA = 42.5 +/- 6.1%). Therefore, in the spontaneously hypertensive rat, contrary to the GABA(A) receptor-mediated control of HR, it appears that GABA(A) receptor-mediated control of tSNA in the NTS is arterial pressure dependent. This study provides new insight into the origin of GABAergic inhibition in NTS circuitry affecting heart rate and sympathetic activity.

Combined effects of high pressure and sodium hydrogen carbonate treatment on beef: improvement of texture and color

NASA Astrophysics Data System (ADS)

Ohnuma, Shun; Kim, Yun-Jung; Suzuki, Atsushi; Nishiumi, Tadayuki

2013-06-01

We investigated the effect of combined high pressure and sodium hydrogen carbonate (NaHCO3) treatment on the physical properties and color of silverside Australian beef. Meat samples were pressurized at 100-500 MPa and the water content, weight reduction, rupture stress, and meat color were determined. The water content of meat treated with NaHCO3 and high pressure (300 MPa) reached a maximum of 70.1%. Weight reduction tended to decrease with high pressure treatment at 300 MPa. Meats treated with NaHCO3 and high pressure at 400 MPa showed a>50% decrease in hardness. Whitening of the meat was reduced by the combined high pressure and NaHCO3 treatment. Therefore, the combined high pressure and NaHCO3 treatment is effective for improvement of beef quality.

Effect of losartan combined with amlodipine or with a thiazide on uric acid levels in hypertensive patients.

PubMed

Rubio-Guerra, Alberto F; Garro-Almendaro, Ana K; Elizalde-Barrera, Cesar I; Suarez-Cuenca, Juan A; Duran-Salgado, Montserrat B

2017-02-01

Hyperuricemia leads to endothelial dysfunction and insulin resistance, and has been associated with diseases such as hypertension. Antihypertensive drugs modify serum uric acid levels, however, few data are available about their combinations on uricemia. In this study we evaluate the effect of two combinations of losartan, with amlodipine or with hydrochlorothiazide, on serum uric acid levels in hypertensive patients. A total of 60 hypertensive patients were randomized in two groups; group LA received losartan/amlodipine (100/5 mg) once a day, whereas LH group received losartan hydrochlorothiazide (100/12.5 mg) once a day for 3 months. In both groups serum uric acid levels were measured at the beginning and end of the study. Patients were evaluated monthly for blood pressure (BP) and adverse events. Statistical analysis was performed with a two-way analysis of variance (ANOVA) for repeated measures. All patients experienced a significant reduction of BP to the same extent (LA 155/94 to 123/79, LH 157/92 to 124/78 mmHg, p > 0.05). In the LA group, serum uric acid decreased from 6.5 ± 1.6 to 4.6 ± 1.3 mg/ml ( p = 0.0001), whereas in the LH group there was a nonsignificant increase from 5.82 ± 1.4 to 5.85 ± 1.5 mg/ml, ( p = 0.936). When both groups were compared, we found a significant reduction ( p < 0.00013) on serum uric acid levels in the LA group. Both combinations decrease BP values to the same extent, however, LA combination showed a reduction on serum uric acid levels, which may contribute to a reduction in the metabolic risk in hypertensive patients.

Effects of Metformin on Endocrine and Metabolic Parameters in Patients with Polycystic Ovary Syndrome.

PubMed

Zahra, M; Shah, M; Ali, A; Rahim, R

2017-02-01

The present study was designed to evaluate the effects of metformin on metabolic and endocrine parameters in patients with polycystic ovary syndrome (PCOS). The study included 40 patients with PCOS. Patients were divided into 2 groups based on whether they will receive metformin (500 mg 3 times a day, n=20) or placebo (n=20) for 3 consecutive months. Serum concentrations of fasting blood glucose, insulin, HOMA-IR, INSL-3, visfatin, FSH, and LH were measured at baseline and after 3 months of therapy. The key endocrine and metabolic parameters significantly changed after metformin treatment. The systolic and diastolic blood pressures were significantly reduced in the metformin group after treatment compared to placebo (p<0.001). A significant reduction in the size of the right ovary was observed after metformin treatment (p=0.05), while no change was found in the size of left ovary (p>0.12). Moreover, a significant reduction was observed in the serum levels of FSH (p>0.01), LH (p>0.001), and visfatin (p>0.001) after metformin treatment. However, HOMA-IR (which is used to assess insulin resistance) failed to reach the statistical significance (p=0.20). We conclude that metformin treatment in females with PCOS showed significant improvement in systolic and diastolic blood pressures. In addition, an improvement in the hormonal profile in the form of reduction in LH, FSH, and visfatin levels was observed. Thus, therapeutic intervention with metformin could be of clinical importance in high-risk group of young females with PCOS. © Georg Thieme Verlag KG Stuttgart · New York.

Articular Contact Area and Pressure in Posteromedial Rotatory Instability of the Elbow.

PubMed

Bellato, Enrico; Fitzsimmons, James S; Kim, Youngbok; Bachman, Daniel R; Berglund, Lawrence J; Hooke, Alexander W; O'Driscoll, Shawn W

2018-03-21

Joint incongruity in posteromedial rotatory instability (PMRI) has been theorized to determine early articular degenerative changes. Our hypothesis was that the articular contact area and contact pressure differ significantly between an intact elbow and an elbow affected by PMRI. Seven cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and allow passive elbow flexion (0° to 90°). The mean contact area and contact pressure data were collected and processed using the Tekscan sensor and software. After testing the intact specimen (intact elbow), a PMRI injury was simulated (PMRI elbow) and the specimen was tested again. The PMRI elbows were characterized by initial joint subluxation and significantly elevated articular contact pressure. Both worsened, corresponding with a reduction in contact area, as the elbow was flexed from 0° until the joint subluxation and incongruity spontaneously reduced (at a mean [and standard error] of 60° ± 5° of flexion), at which point the mean contact pressure decreased from 870 ± 50 kPa (pre-reduction) to 440 ± 40 kPa (post-reduction) (p < 0.001) and the mean contact area increased from 80 ± 8 mm to 150 ± 58 mm (p < 0.001). This reduction of the subluxation was also followed by a shift of the contact area from the coronoid fracture edge toward the lower portion of the coronoid. At the flexion angle at which the PMRI elbows reduced, both the contact area and the contact pressure of the intact elbows differed significantly from those of the PMRI elbows, both before and after the elbow reduction (p < 0.001). The reduction in contact area and increased contact pressures due to joint subluxation and incongruity could explain the progressive arthritis seen in some elbows affected by PMRI. This biomechanical study suggests that the early degenerative changes associated with PMRI reported in the literature could be subsequent to joint incongruity and an increase in contact pressure between the coronoid fracture surface and the trochlea.

Combination of endolysins and high pressure to inactivate Listeria monocytogenes.

PubMed

van Nassau, Tomas J; Lenz, Christian A; Scherzinger, Anna S; Vogel, Rudi F

2017-12-01

Outbreaks of listeriosis are often related to the consumption of low-processed ready-to-eat food products (e.g. soft cheeses or smoked fish) contaminated with Listeria monocytogenes. Traditional preservation techniques, such as heat treatment, cannot eliminate Listeria from these products without strongly affecting the quality of the foods. We therefore investigated the use of endolysin (PlyP40, Ply511, or PlyP825) in combination with high hydrostatic pressure processing to kill L. monocytogenes in buffer. The results demonstrated a more than additive effect when both treatments were combined. For example, whereas 0.16 μg/mL PlyP825 or 300 MPa (1 min, 30 °C) applied individually reduced the cell count by 0.2 and 0.3 log cfu, respectively, a combined treatment resulted in a reduction of 5.5 log cfu. Similar results were obtained for the other endolysins combined with high pressure processing. We also showed that the synergistic inactivation of cells by endolysin and HHP is possible at a pressure level of only 200 MPa (2 min, 30 °C). Thus, the application of endolysins did not only substantially increase the bactericidal effect of high pressure, but it also enabled the inactivation of bacterial cells at much lower pressure levels. This shows the potential of using such combined processes for the inactivation of L. monocytogenes and food preservation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using Decomposition Analysis to Identify Modifiable Racial Disparities in the Distribution of Blood Pressure in the United States.

PubMed

Basu, Sanjay; Hong, Anthony; Siddiqi, Arjumand

2015-08-15

To lower the prevalence of hypertension and racial disparities in hypertension, public health agencies have attempted to reduce modifiable risk factors for high blood pressure, such as excess sodium intake or high body mass index. In the present study, we used decomposition methods to identify how population-level reductions in key risk factors for hypertension could reshape entire population distributions of blood pressure and associated disparities among racial/ethnic groups. We compared blood pressure distributions among non-Hispanic white, non-Hispanic black, and Mexican-American persons using data from the US National Health and Nutrition Examination Survey (2003-2010). When using standard adjusted logistic regression analysis, we found that differences in body mass index were the only significant explanatory correlate to racial disparities in blood pressure. By contrast, our decomposition approach provided more nuanced revelations; we found that disparities in hypertension related to tobacco use might be masked by differences in body mass index that significantly increase the disparities between black and white participants. Analysis of disparities between white and Mexican-American participants also reveal hidden relationships between tobacco use, body mass index, and blood pressure. Decomposition offers an approach to understand how modifying risk factors might alter population-level health disparities in overall outcome distributions that can be obscured by standard regression analyses. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.

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

PubMed

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 < 0.05), while LSNA increased in a step manner by 15.3% ± 2% (P < 0.05) relative to the NREM level. Systemic arterial pressure increased gradually (P < 0.05), while heart rate decreased in a step manner (P < 0.05) during REM 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.

Geometry and starvation effects in hydrodynamic lubrication

NASA Technical Reports Server (NTRS)

Brewe, D.; Hamrock, B. J.

1982-01-01

Numerical methods were used to detemine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. A minimum film thickness equation as a function of both the ratio of dimensionless load to dimensionless speed and inlet supply level was determined. By comparing the film generated under the starved inlet condition with the film generated from the fully flooded inlet, an expression for the film reduction factor was obtained. Based on this factor a starvation threshold was defined as well as a critically starved inlet. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three dimensional isometric plots and also in the form of contour plots.

Single-dose volume regulation algorithm for a gas-compensated intrathecal infusion pump.

PubMed

Nam, Kyoung Won; Kim, Kwang Gi; Sung, Mun Hyun; Choi, Seong Wook; Kim, Dae Hyun; Jo, Yung Ho

2011-01-01

The internal pressures of medication reservoirs of gas-compensated intrathecal medication infusion pumps decrease when medication is discharged, and these discharge-induced pressure drops can decrease the volume of medication discharged. To prevent these reductions, the volumes discharged must be adjusted to maintain the required dosage levels. In this study, the authors developed an automatic control algorithm for an intrathecal infusion pump developed by the Korean National Cancer Center that regulates single-dose volumes. The proposed algorithm estimates the amount of medication remaining and adjusts control parameters automatically to maintain single-dose volumes at predetermined levels. Experimental results demonstrated that the proposed algorithm can regulate mean single-dose volumes with a variation of <3% and estimate the remaining medication volume with an accuracy of >98%. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Analysis of starvation effects on hydrodynamic lubrication in nonconforming contacts

NASA Technical Reports Server (NTRS)

Brewe, D. E.; Hamrock, B. J.

1981-01-01

Numerical methods were used to determine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. A minimum-fill-thickness equation as a function of both the ratio of dimensionless load to dimensionless speed and inlet supply level was determined. By comparing the film generated under the starved inlet condition with the film generated from the fully flooded inlet, an expression for the film reduction factor was obtained. Based on this factor a starvation threshold was defined as well as a critically starved inlet. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three dimensional isometric plots and also in the form of contour plots.

Geometry and starvation effects in hydrodynamic lubrication

NASA Technical Reports Server (NTRS)

Brewe, D. E.; Hamrock, B. J.

1982-01-01

Numerical methods were used to determine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. A minimum-film-thickness equation as a function of both the ratio of dimensionless load to dimensionless speed and inlet supply level was determined. By comparing the film generated under the starved inlet condition with the film generated from the fully flooded inlet, an expression for the film reduction factor was obtained. Based on this factor a starvation threshold was defined as well as a critically starved inlet. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three dimensional isometric plots and also in the form of contour plots.

Intravenous human umbilical cord blood improves electrophysiological and metabolic properties in ISO induced myocardial necrosis in rats.

PubMed

Mohan, Mahalaxmi; Rokade, Rahul; Kasturet, Sanjay

2013-03-01

Rats treated with isoproterenol (ISO, 85 mg/kg, sc, twice at an interval of 24 h) showed a significant increase in heart rate, mean arterial blood pressure, pressure rate index, ST elevation on ECG, and a significant increase in the levels of cardiac marker enzymes- lactate dehydrogenase, and creatine kinase in serum and a significant reduction in superoxide dismutase, and catalase and increase in thiobarbituric acid reactive substance activity in heart tissue. Treatment with Human umbilical cord blood (hUCBC; 500 and 1000 microL, iv, via the tail vein; 2 h after the second dose of ISO) significantly restored back to normal levels and showed a lesser degree of cellular infiltration and infarct size in histopathological and planimetry studies respectively. Thus, hUCBC ameliorates cardiotoxic effects of isoproterenol and may be of value in the treatment of myocardial infarction.

[Music and Glaucoma].

PubMed

Plange, N

2017-02-01

Music may have multiple influences on the human organism. A possible therapeutic effect for patients with glaucoma has been postulated, aside from the known impact of music on the cardiovascular system, psychogenic effects and a short-term improvement in mental performance (Mozart effect). The higher level of mental stress in patients with glaucoma and type-A personality behaviour may be related to higher intraocular pressure in patients with glaucoma. Relaxing music may have a positive impact in these patients, related to a reduction in intraocular pressure or its fluctuations. However, only limited data exist on the effects of music on intraocular pressure. No clinical studies have yet been performed to investigate the effect of music or music therapy on glaucoma progression. The music of Mozart may influence visual field examinations, possibly due to a positive short term effect on mental performance. This factor needs to be addressed in studies dealing with the effect of music in glaucoma. The relevance of intraocular pressure increases in professional wind instrument players is controversial. An increased level of care might be advisable in patients with advanced glaucoma. The influences of music on humans, altered personality profiles in patients with glaucoma and the studies showing some effect of stress on intraocular pressure stress the relevance of psychological support for glaucoma patients, who are confronted with a disease with a high longterm risk of blindness. Georg Thieme Verlag KG Stuttgart · New York.

Chronic effects of workplace noise on blood pressure and heart rate.

PubMed

Lusk, Sally L; Hagerty, Bonnie M; Gillespie, Brenda; Caruso, Claire C

2002-01-01

Environmental noise levels in the United States are increasing, yet there are few studies in which the nonauditory effects of workplace noise are assessed. In the current study, the authors examined chronic effects of noise on blood pressure and heart rate in 374 workers at an automobile plant. Data were collected from subjects prior to the start of their workshift. Participants completed questionnaires about diet, alcohol use, lifestyle, noise annoyance, use of hearing protection, noise exposure outside of the work environment, personal and family health histories, and demographic information. Resting blood pressure, heart rate, and body mass index were obtained. Noise exposure levels were extracted retrospectively from company records for each participant for the past 5 yr. Summary statistics were generated for each variable, and the authors performed bivariate correlations to identify any unadjusted associations. The authors then completed statistical modeling to investigate the effects of noise on blood pressure and heart rate, after they controlled for other variables (e.g., gender, race, age). The authors controlled for confounding variables, after which use of hearing protection in high-noise areas was a significant predictor of a decrease in both systolic and diastolic blood pressures. The results suggested that the reduction of noise exposure by means of engineering controls or by consistent use of hearing protection by workers may positively affect health outcomes.

Achieved Blood Pressure and Outcomes in the Secondary Prevention of Small Subcortical Strokes Trial.

PubMed

Odden, Michelle C; McClure, Leslie A; Sawaya, B Peter; White, Carole L; Peralta, Carmen A; Field, Thalia S; Hart, Robert G; Benavente, Oscar R; Pergola, Pablo E

2016-01-01

Studies suggest a J-shaped association between blood pressure and cardiovascular events in the setting of intensive systolic blood pressure control; whether there is a similar association with stroke remains less well established. The Secondary Prevention of Small Subcortical Strokes was a randomized trial to evaluate higher (130-149 mm Hg) versus lower (<130 mm Hg) systolic blood pressure targets in participants with recent lacunar infarcts. We evaluated the association of mean achieved blood pressure, 6 months after randomization, and recurrent stroke, major vascular events, and all-cause mortality. After a mean follow up of 3.7 years, there was a J-shaped association between achieved blood pressure and outcomes; the lowest risk was at ≈124 and 67 mm Hg systolic and diastolic blood pressure, respectively. For example, above a systolic blood pressure of 124 mm Hg, 1 standard deviation higher (11.1 mm Hg) was associated with increased mortality (adjusted hazard ratio: 1.9; 95% confidence interval: 1.4, 2.7), whereas below this level, this relationship was inverted (0.29; 0.10, 0.79), P<0.001 for interaction. Above a diastolic blood pressure of 67 mm Hg, a 1 standard deviation higher (8.2 mm Hg) was associated with an increased risk of stroke (2.2; 1.4, 3.6), whereas below this level, the association was in the opposite direction (0.34; 0.13, 0.89), P=0.02 for interaction. The lowest risk of all events occurred at a nadir of ≈120 to 128 mm Hg systolic blood pressure and 65 to 70 mm Hg diastolic blood pressure. Future studies should evaluate the impact of excessive blood pressure reduction, especially in older populations with preexisting vascular disease. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00059306. © 2015 American Heart Association, Inc.

Blood pressure reduction and antihypertensive medication use in the losartan intervention for endpoint reduction in hypertension (LIFE) study in patients with hypertension and left ventricular hypertrophy.

PubMed

Devereux, Richard B; de Faire, Ulf; Fyhrquist, Frej; Harris, Katherine E; Ibsen, Hans; Kjeldsen, Sverre E; Lederballe-Pedersen, Ole; Lindholm, Lars H; Nieminen, Markku S; Omvik, Per; Oparil, Suzanne; Wedel, Hans; Hille, Darcy A; Dahlöf, Björn

2007-02-01

To compare blood pressure response and antihypertensive medication use visit-by-visit from baseline in patients receiving losartan-based or atenolol-based therapy in the LIFE study. LIFE was a randomized, double-blind trial comparing losartan-based and atenolol-based treatment regimens on the primary composite endpoint of death, myocardial infarction (MI), or stroke in 9193 patients aged 55-80 years with hypertension and left ventricular hypertrophy. Systolic and diastolic, pulse, and mean arterial pressures, blood pressure responder rates, distribution of open-label antihypertensive agents utilized, and the proportion of patients on randomized treatment were determined for each group at each clinic visit over a follow-up period of at least 4 years. Overall blood pressure reductions were comparable in the losartan-based and atenolol-based treatment groups. The mean reductions in sitting trough systolic and diastolic blood pressures from baseline to the end of follow-up (or last visit before a primary endpoint event) were 30.2/16.6 mmHg in the losartan group and 29.1/16.8 mmHg in the atenolol group. The time-averaged difference in overall mean arterial pressure was similar between groups. The proportion of patients on individual dose combinations varied visit by visit but was generally comparable between groups. During the entire study, 56% (2579/4605) of losartan-treated patients received at least one dose of the combination of losartan 100 mg plus hydrochlorothiazide 12.5 mg and 51% of atenolol-treated patients received 100 mg of atenolol plus hydrochlorothiazide 12.5 mg at some time during the study. Differences in blood pressure or distribution of add-on medications between treatment groups were not evident in the LIFE trial and, thus, cannot account for the observed outcome difference in the primary endpoint of risk reduction of the composite of cardiovascular death, stroke and MI favoring losartan.

Quantitative Discomanometry: Correlation of Intradiscal Pressure Values to Pain Reduction in Patients With Intervertebral Disc Herniation Treated With Percutaneous, Minimally Invasive, Image-Guided Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filippiadis, Dimitrios K., E-mail: dfilippiadis@yahoo.gr; Mazioti, A., E-mail: argyromazioti@yahoo.gr; Papakonstantinou, O., E-mail: sogofianol@gmail.com

Purpose: To illustrate quantitative discomanometry's (QD) diagnostic efficacy and predictive value in discogenic-pain evaluation in a prospective study correlating intradiscal pressure values with pain reduction after percutaneous image-guided technique (i.e., percutaneous decompression, PD). Materials and Methods: During the last 3 years, 36 patients [21 male and 15 female (mean age 36 {+-} 5.8 years)] with intervertebral disc hernia underwent QD before PD. Under absolute sterilization and fluoroscopy, a mixture of contrast medium and normal saline (3:1 ratio) was injected. A discmonitor performed a constant rate injection and recorded pressure and volume values, thus producing the relative pressure-volume curve. PD wasmore » then performed. Pain reduction and improved mobility were recorded at 3, 12, and 24 months after PD using clinical evaluation and a numeric visual scale (NVS; 0 to 10 units). Results: Mean pain values of 7.5 {+-} 1.9 (range 4 to 8) NVS units were recorded before PD; these decreased to 2.9 {+-} 2.44 at 3 months, 1.0 {+-} 1.9 at 12 months, and 1.0 {+-} 1.9 NVS units at 24 months after PD. Recorded correlations (pressure, volume, significant pain-reduction values) with bilateral statistical significance included a maximum injected volume of 2.4 ml (p = 0.045), P{sub o} < 14 psi [initial pressure required to inject 0.1 ml of the mixture inside the disc (p = 0.05)], P{sub max} {<=} 65 psi [greatest pressure value on the curve (p = 0.018)], and P{sub max} - P{sub o} {<=} 47 psi (p = 0.038). Patients meeting these pressure or volume cut-off points, either independently or as a total, had significant pain reduction (>4 NVS units) after PD. No complications were noted. Conclusions: QD is an efficient technique that may have predictive value for discogenic pain evaluation. It might serve as a useful tool for patient selection for intervertebral disc therapies.« less

Prediction on the Enhancement of the Impact Sound Insulation to a Floating Floor with Resilient Interlayer

NASA Astrophysics Data System (ADS)

Huang, Xianfeng; Meng, Yao; Huang, Riming

2017-10-01

This paper describes a theoretical method for predicting the improvement of the impact sound insulation to a floating floor with the resilient interlayer. Statistical energy analysis (SEA) model, which is skilful in calculating the floor impact sound, is set up for calculating the reduction in impact sound pressure level in downstairs room. The sound transmission paths which include direct path and flanking paths are analyzed to find the dominant one; the factors that affect impact sound reduction for a floating floor are explored. Then, the impact sound level in downstairs room is determined and comparisons between predicted and measured data are conducted. It is indicated that for the impact sound transmission across a floating floor, the flanking path impact sound level contribute tiny influence on overall sound level in downstairs room, and a floating floor with low stiffness interlayer exhibits favorable sound insulation on direct path. The SEA approach applies to the floating floors with resilient interlayers, which are experimentally verified, provides a guidance in sound insulation design.

Use of negative-pressure dressings and split-thickness skin grafts following penile shaft reduction and reduction scrotoplasty in the management of penoscrotal elephantiasis.

PubMed

Stokes, Tracey H; Follmar, Keith E; Silverstein, Ari D; Weizer, Alon Z; Donatucci, Craig F; Anderson, Everett E; Erdmann, Detlev

2006-06-01

From 1988 to 2005, 8 men who presented with penoscrotal elephantiasis underwent penile shaft degloving and reduction scrotoplasty, followed by transplantation of a split-thickness skin graft (STSG) to the penile shaft. The etiology of elephantiasis in these patients included self-injection of viscous fluid and postsurgical obstructive lymphedema. In the 6 most recent cases, negative-pressure dressings were applied over the STSG to promote graft take, and STSG take rate was 100%. The results of our series corroborate those of a previous report, which showed circumferential negative-pressure dressings to be safe and efficacious in bolstering STSGs to the penile shaft. Furthermore, these results suggest that the use of negative-pressure dressings may improve graft take in this patient population.

Jet Noise Reduction by Microjets - A Parametric Study

NASA Technical Reports Server (NTRS)

Zaman, K. B. M. Q.

2010-01-01

The effect of injecting tiny secondary jets (microjets ) on the radiated noise from a subsonic primary jet is studied experimentally. The microjets are injected on to the primary jet near the nozzle exit with variable port geometry, working fluid and driving pressure. A clear noise reduction is observed that improves with increasing jet pressure. It is found that smaller diameter ports with higher driving pressure, but involving less thrust and mass fraction, can produce better noise reduction. A collection of data from the present as well as past experiments is examined in an attempt to correlate the noise reduction with the operating parameters. The results indicate that turbulent mixing noise reduction, as monitored by OASPL at a shallow angle, correlates with the ratio of jet to primary jet driving pressures normalized by the ratio of corresponding diameters (p d /pjD). With gaseous injection, the spectral amplitudes decrease at lower frequencies while an increase is noted at higher frequencies. It is apparent that this amplitude crossover is at least partly due to shock-associated noise from the underexpanded jets themselves. Such crossover is not seen with water injection since the flow in that case is incompressible and there is no shock-associated noise. Centerline velocity data show that larger noise reduction is accompanied by faster jet decay as well as significant reduction in turbulence intensities. While a physical understanding of the dependence of noise reduction on p d /pjD remains unclear, given this correlation, an analysis explains the observed dependence of the effect on various other parameters.

Computational Quantification of the Cardiac Energy Consumption during Intra-Aortic Balloon Pumping Using a Cardiac Electromechanics Model

PubMed Central

Lim, Ki Moo; Lee, Jeong Sang; Gyeong, Min-Soo; Choi, Jae-Sung; Choi, Seong Wook

2013-01-01

To quantify the reduction in workload during intra-aortic balloon pump (IABP) therapy, indirect parameters are used, such as the mean arterial pressure during diastole, product of heart rate and peak systolic pressure, and pressure-volume area. Therefore, we investigated the cardiac energy consumption during IABP therapy using a cardiac electromechanics model. We incorporated an IABP function into a previously developed electromechanical model of the ventricle with a lumped model of the circulatory system and investigated the cardiac energy consumption at different IABP inflation volumes. When the IABP was used at inflation level 5, the cardiac output and stroke volume increased 11%, the ejection fraction increased 21%, the stroke work decreased 1%, the mean arterial pressure increased 10%, and the ATP consumption decreased 12%. These results show that although the ATP consumption is decreased significantly, stroke work is decreased only slightly, which indicates that the IABP helps the failed ventricle to pump blood efficiently. PMID:23341718

Computational quantification of the cardiac energy consumption during intra-aortic balloon pumping using a cardiac electromechanics model.

PubMed

Lim, Ki Moo; Lee, Jeong Sang; Gyeong, Min-Soo; Choi, Jae-Sung; Choi, Seong Wook; Shim, Eun Bo

2013-01-01

To quantify the reduction in workload during intra-aortic balloon pump (IABP) therapy, indirect parameters are used, such as the mean arterial pressure during diastole, product of heart rate and peak systolic pressure, and pressure-volume area. Therefore, we investigated the cardiac energy consumption during IABP therapy using a cardiac electromechanics model. We incorporated an IABP function into a previously developed electromechanical model of the ventricle with a lumped model of the circulatory system and investigated the cardiac energy consumption at different IABP inflation volumes. When the IABP was used at inflation level 5, the cardiac output and stroke volume increased 11%, the ejection fraction increased 21%, the stroke work decreased 1%, the mean arterial pressure increased 10%, and the ATP consumption decreased 12%. These results show that although the ATP consumption is decreased significantly, stroke work is decreased only slightly, which indicates that the IABP helps the failed ventricle to pump blood efficiently.

Canagliflozin-current status in the treatment of type 2 diabetes mellitus with focus on clinical trial data

PubMed Central

Bhatia, Jagriti; Gamad, Nanda; Bharti, Saurabh; Arya, Dharamvir Singh

2014-01-01

Canagliflozin (CFZ) is a member of new class of glucose lowering agents, sodium-glucose co-transporter (SGLT) inhibitors, which got approval by food and drug administration. It has insulin independent action by blocking the transporter protein SGLT2 in the kidneys, resulting in urinary glucose excretion and reduction in blood glucose levels. In clinical trials, CFZ significantly decreased HbA1c level when administered either as monotherapy or as combined therapy with other anti-diabetic drugs. Intriguingly, it showed additional benefits like weight reduction and lowering of blood pressure. The commonly observed side effects were urinary and genital infections. It has exhibited favorable pharmacokinetic and pharmacodynamic profiles even in patients with renal and hepatic damage. Hence, this review purports to outline CFZ as a newer beneficial drug for type 2 diabetes mellitus. PMID:24936262

The role of ants, birds and bats for ecosystem functions and yield in oil palm plantations.

PubMed

Denmead, Lisa H; Darras, Kevin; Clough, Yann; Diaz, Patrick; Grass, Ingo; Hoffmann, Munir P; Nurdiansyah, Fuad; Fardiansah, Rico; Tscharntke, Teja

2017-07-01

One of the world's most important and rapidly expanding crops, oil palm, is associated with low levels of biodiversity. Changes in predator communities might alter ecosystem services and subsequently sustainable management but these links have received little attention to date. Here, for the first time, we manipulated ant and flying vertebrate (birds and bats) access to oil palms in six smallholder plantations in Sumatra (Indonesia) and measured effects on arthropod communities, related ecosystem functions (herbivory, predation, decomposition and pollination) and crop yield. Arthropod predators increased in response to reductions in ant and bird access, but the overall effect of experimental manipulations on ecosystem functions was minimal. Similarly, effects on yield were not significant. We conclude that ecosystem functions and productivity in oil palm are, under current levels of low pest pressure and large pollinator populations, robust to large reductions of major predators. © 2017 by the Ecological Society of America.

Baroreflex Responses to Acute Changes in Blood Volume in Humans

NASA Technical Reports Server (NTRS)

Thompson, Cynthia A.; Tatro, Dana L.; Ludwig, David A.; Convertino, Victor A.

1990-01-01

To test the hypothesis that acute changes in plasma volume affect the stimulus-response relations of high- and low- pressure baroreflexes, eight men (27-44 yr old) underwent measurements for carotid-cardiac and cardiopulmonary baro-reflex responses under the following three volemic conditions: hypovolemic, normovolemic, and hypervolemic. The stimulus- response relation of the carotid-cardiac response curve was generated using a neck cuff device, which delivered pressure changes between +40 and -65 mmHg in continuous steps of 15 mmHg. The stimulus-response relationship, of the cardio-pulmonary baroreflex were studied by measurements of Forearm Vascular Resistance (FVR) and Peripheral Venous Pressure (PVP) during low levels of lower body negative pressure (O to -20 mmHg). The results indicate greater demand for vasoconstriction for equal reductions in venous pressure during progressive hypovolemia; this condition may compromise the capacity to provide adequate peripheral resistance during severe orthostatic stress. Fluid loading before reentry after spaceflight may act to restore vasoconstrictive capacity of the cardiopulmonary baroreflex but may not be an effective countermeasure against potential post- flight impairment of the carotid-cardiac baroreflex.

Report From BPTCS Project Team On Evaluation Of Additive Manufacturing For Pressure Retaining Equipment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rawls, G.

ASME is evaluating the use of additive manufacturing (AM) for the construction of pressure equipment. The information in this report assesses available AM technologies for direct metal fabrication of pressure equipment. Background information is included in the report to provide context for those not experienced in AM technology. Only commercially available technologies for direct metal fabrication are addressed in the report because these AM methods are the only viable approaches for the construction of pressure equipment. Metal AM technologies can produce near-net shape parts by using multiple layers of material from a three dimensional (3D) design model of the geometry.more » Additive manufacturing of metal components was developed from polymer based rapid prototyping or 3D printing. At the current maturity level, AM application for pressure equipment has the potential to reduce delivery times and costs for complex shapes. AM will also lead to a reduction in the use of high cost materials, since parts can be created with corrosion resistant layers of high alloy material and structural layers of lower cost materials.« less

Despite similar reduction of blood pressure and renal ANG II and ET-1 levels aliskiren but not losartan normalizes albuminuria in hypertensive Ren-2 rats.

PubMed

Vanourková, Z; Kramer, H J; Husková, Z; Cervenka, L; Vanecková, I

2010-01-01

The relationship between angiotensin II (ANG II) and endothelin-1 (ET-1) is known to be complex; both peptides can initiate and potentiate the gene expression of each other. This pilot study investigated the effects of the AT(1) receptor blocker losartan or the direct renin inhibitor aliskiren on mean arterial pressure (MAP) and albuminuria and the renal ANG II and ET-1 levels. 3-month-old male Ren-2 transgenic rats (TGR) were treated either with losartan (5 mg kg(-1) day(-1)) or aliskiren (10 mg kg(-1) day(-1)) for 10 weeks. At the end of the experiment, rats were decapitated and cortical and papillary parts of kidneys were separated. Plasma and tissue ANG II levels were measured by RIA and tissue ET-1 concentrations by ELISA. In all four groups of animals ET-1 levels were lowest in renal cortex and more than 100-fold higher in the papilla. Cortical and papillary ET-1 concentrations in untreated TGR significantly exceeded those of control HanSD rats and were significantly depressed by both drugs. In both strains, papillary ANG II concentrations were moderately but significantly higher than cortical ANG II, TGR exhibited higher ANG II levels both in cortex and papilla as compared to control HanSD rats. Aliskiren and losartan at the doses used depressed similarly the levels of ANG II in cortex and papilla and reduced ET-1 significantly in the renal cortex and papilla below control levels in HanSD rats. Albuminuria, which was more than twice as high in TGR as in HanSD rats, was normalized with aliskiren and reduced by 28% with losartan, although MAP was reduced to a similar degree by both drugs. Despite similar reductions of MAP and renal ET-1 and ANG II levels aliskiren appears to be more effective than losartan, at the doses used, in reducing albuminuria in heterozygous hypertensive Ren-2 rats.

Statistical parametric mapping of the regional distribution and ontogenetic scaling of foot pressures during walking in Asian elephants (Elephas maximus).

PubMed

Panagiotopoulou, Olga; Pataky, Todd C; Hill, Zoe; Hutchinson, John R

2012-05-01

Foot pressure distributions during locomotion have causal links with the anatomical and structural configurations of the foot tissues and the mechanics of locomotion. Elephant feet have five toes bound in a flexible pad of fibrous tissue (digital cushion). Does this specialized foot design control peak foot pressures in such giant animals? And how does body size, such as during ontogenetic growth, influence foot pressures? We addressed these questions by studying foot pressure distributions in elephant feet and their correlation with body mass and centre of pressure trajectories, using statistical parametric mapping (SPM), a neuro-imaging technology. Our results show a positive correlation between body mass and peak pressures, with the highest pressures dominated by the distal ends of the lateral toes (digits 3, 4 and 5). We also demonstrate that pressure reduction in the elephant digital cushion is a complex interaction of its viscoelastic tissue structure and its centre of pressure trajectories, because there is a tendency to avoid rear 'heel' contact as an elephant grows. Using SPM, we present a complete map of pressure distributions in elephant feet during ontogeny by performing statistical analysis at the pixel level across the entire plantar/palmar surface. We hope that our study will build confidence in the potential clinical and scaling applications of mammalian foot pressures, given our findings in support of a link between regional peak pressures and pathogenesis in elephant feet.

Problem of intensity reduction of acoustic fields generated by gas-dynamic jets of motors of the rocket-launch vehicles at launch

NASA Astrophysics Data System (ADS)

Vorobyov, A. M.; Abdurashidov, T. O.; Bakulev, V. L.; But, A. B.; Kuznetsov, A. B.; Makaveev, A. T.

2015-04-01

The present work experimentally investigates suppression of acoustic fields generated by supersonic jets of the rocket-launch vehicles at the initial period of launch by water injection. Water jets are injected to the combined jet along its perimeter at an angle of 0° and 60°. The solid rocket motor with the rocket-launch vehicles simulator case is used at tests. Effectiveness of reduction of acoustic loads on the rocket-launch vehicles surface by way of creation of water barrier was proved. It was determined that injection angle of 60° has greater effectiveness to reduce pressure pulsation levels.

Central systolic blood pressure is associated with ethnicity and cardiovascular disease risk factors in Chinese middle-aged population.

PubMed

Wang, Zengwu; Hao, Guang; Zhang, Linfeng; Chen, Zuo; Wang, Xin; Guo, Min; Tian, Ye; Shao, Lan; Zhu, Manlu

2016-02-01

Central systolic blood pressure (CSBP) is a useful prognostic aid in the reduction and prevention of cardiovascular diseases. However, data regarding the distribution of CSBP in China are not available. The study aimed at assessing the distribution of CSBP and examining its relationship with potential cardiovascular risk factors in the Chinese middle-aged population. A cross-sectional study. A cross-sectional survey on cardiovascular risk factors across China was conducted in 2009-2010. CSBP levels were estimated using the non-invasive BPro device with A-Pulse central aortic systolic pressure software. The study population included 9113 individuals (mean age 49.84 years; 53.37% women). The CSBP levels (mean (standard deviation)) were 119.46 (17.51) mmHg in men and 119.81 (19.29) mmHg in women. CSBP levels were higher in rural than urban and lower in the southern than the northern populations (both P < 0.05). The Han ethnic group had higher CSBP levels than the Tibetans (P < 0.05) but similar to those in the Mongolian, Uyghur, Kazak and Akha groups. Irrespective of gender, the mean CSBP level was higher in individuals with diabetes and hypertension than in those without these disorders (P < 0.05). CSBP was positively associated with cardiovascular risk factors such as age, female gender, body mass index, systolic and diastolic blood pressure, and negatively associated with heart rate. CSBP estimated using the BPro device correlates with various cardiovascular risk factors. Our results may help establish future reference values in the Chinese middle-aged population. © The European Society of Cardiology 2015.

Investigation of powder injection moulded oblique fin heat sinks

NASA Astrophysics Data System (ADS)

Sai, Vadri Siva

The present work attempts to study the fluid flow and heat transfer characteristics of PIM oblique finned microchannel heat sink both numerically and experimentally. Experimental results such as thermal resistance and pressure drop have been well validated with ANSYS FLUENT simulations. Hot spots are observed at the most downstream location of the channel is due to the effect of flow migration. Finally, a novel technique has been proposed to reduce the pressure drop on creating additional channels by removing some material at the middle portion of oblique fins. It is found that the creation of oblique cuts incurred a reduction in both pressure drop and Nuavg up to 31.36 % and 16.66 % respectively at a flow rate of 500 ml/min. Nevertheless, for all the flowrates considered in this analysis. % reduction in pressure drop is almost double as compared with % reduction in Nuavg. Therefore, this analysis is beneflcial in reducing the additional cost incurs due to pressure drop penalty.

Influence of hydrostatic pressure on dynamics and spatial distribution of protein partial molar volume: time-resolved surficial Kirkwood-Buff approach.

PubMed

Yu, Isseki; Tasaki, Tomohiro; Nakada, Kyoko; Nagaoka, Masataka

2010-09-30

The influence of hydrostatic pressure on the partial molar volume (PMV) of the protein apomyoglobin (AMb) was investigated by all-atom molecular dynamics (MD) simulations. Using the time-resolved Kirkwood-Buff (KB) approach, the dynamic behavior of the PMV was identified. The simulated time average value of the PMV and its reduction by 3000 bar pressurization correlated with experimental data. In addition, with the aid of the surficial KB integral method, we obtained the spatial distributions of the components of PMV to elucidate the detailed mechanism of the PMV reduction. New R-dependent PMV profiles identified the regions that increase or decrease the PMV under the high pressure condition. The results indicate that besides the hydration in the vicinity of the protein surface, the outer space of the first hydration layer also significantly influences the total PMV change. These results provide a direct and detailed picture of pressure induced PMV reduction.

Safety and feasibility of achieving lower systolic blood pressure goals in persons with type 2 diabetes: the SANDS trial.

PubMed

Weir, Matthew R; Yeh, Fawn; Silverman, Angela; Devereux, Richard B; Galloway, James M; Henderson, Jeffrey A; Howard, William J; Russell, Marie; Wilson, Charlton; Ratner, Robert; Sorkin, John; Umans, Jason G; Fleg, Jerome L; Stylianou, Mario; Lee, Elisa; Howard, Barbara V

2009-10-01

The Stop Atherosclerosis in Native Diabetics Study (SANDS) was a randomized open-label clinical trial in type 2 diabetics designed to examine the effects of intensive reduction of blood pressure, aggressive vs standard goals (< or =115/75 mm Hg vs < or =130/80 mm Hg), and low-density lipoprotein (LDL) cholesterol on the composite outcome of change in carotid intimal-medial thickness and cardiovascular events. The study demonstrated that in conjunction with a lower LDL cholesterol target of 70 mg/dL, aggressive systolic blood pressure-lowering resulted in a reduction in carotid intimal-medial thickness and left ventricular mass without measurable differences in cardiovascular events. The blood pressure treatment algorithm included renin-angiotensin system blockade, with other agents added if necessary. The authors conclude that both standard and more aggressive systolic blood pressure reduction can be achieved with excellent safety and good tolerability in patients with type 2 diabetes mellitus.

Efficacy of a church-based lifestyle intervention programme to control high normal blood pressure and/or high normal blood glucose in church members: a randomized controlled trial in Pretoria, South Africa.

PubMed

Pengpid, Supa; Peltzer, Karl; Skaal, Linda

2014-06-06

In persons 15 years and above in South Africa the prevalence of pre-diabetes and diabetes has been estimated at 9.1% and 9.6%, respectively, and the prevalence of systolic prehypertension and hypertension, 38.2% and 24.6%, respectively. Elevated blood glucose and elevated blood pressure are prototype of preventable chronic cardiovascular disease risk factors.Lifestyle interventions have been shown to control high normal blood pressure and/or high normal blood glucose. This study proposes to evaluate the efficacy of a community (church)-based lifestyle intervention programme to control high normal blood pressure and/or high normal blood glucose in church members in a randomized controlled trial in Gauteng, South Africa. The objectives are to: (1) measure non-communicable diseases profile, including hypertension and diabetes, health behaviours, weight management and psychological distress of church members; (2) measure the reduction of blood glucose and blood pressure levels after the intervention; (3) prevent the development of impaired glucose tolerance; (4) compare health behaviours, weight management and psychological distress, blood glucose and blood pressure levels between intervention and control groups, and within group during 6, 12, 24 and 36 months during and post intervention. The study will use a group-randomized design, recruiting 300 church members from 12 churches. Churches will be randomly assigned to experimental and control conditions. Lifestyle interventions may prevent from the development of high blood pressure and/or diabetes. The findings will impact public health and will enable the health ministry to formulate policy related to lifestyle interventions to control blood pressure and glucose. PACTR201105000297151.

Impact of a cleaner-burning cookstove intervention on blood pressure in Nicaraguan women.

PubMed

Clark, M L; Bachand, A M; Heiderscheidt, J M; Yoder, S A; Luna, B; Volckens, J; Koehler, K A; Conway, S; Reynolds, S J; Peel, J L

2013-04-01

Few studies have evaluated the cardiovascular-related effects of indoor biomass burning or the role of characteristics such as age and obesity status, in this relationship. We examined the impact of a cleaner-burning cookstove intervention on blood pressure among Nicaraguan women using an open fire at baseline; we also evaluated heterogeneity of the impact by subgroups of the population. We evaluated changes in systolic and diastolic blood pressure from baseline to post-intervention (range: 273-383 days) among 74 female cooks. We measured indoor fine particulate matter (PM(2.5); N = 25), indoor carbon monoxide (CO; N = 32), and personal CO (N = 30) concentrations. Large mean reductions in pollutant concentrations were observed for all pollutants; for example, indoor PM(2.5) was reduced 77% following the intervention. However, pollution distributions (baseline and post-intervention) were wide and overlapping. Although substantial reductions in blood pressure were not observed among the entire population, a 5.9 mmHg reduction [95% confidence interval (CI): -11.3, -0.4] in systolic blood pressure was observed among women aged 40 or more years and a 4.6 mmHg reduction (95% CI: -10.0, 0.8) was observed among obese women. Results from this study provide an indication that certain subgroups may be more likely to experience improvements in blood pressure following a cookstove intervention. © 2012 John Wiley & Sons A/S.

Hover Acoustic Characteristics of the XV-15 with Advanced Technology Blades

NASA Technical Reports Server (NTRS)

Conner, David A.; Wellman, J. Brent

1993-01-01

An experiment has been performed to investigate the far-field hover acoustic characteristics of the XV-15 aircraft with advanced technology blades (ATB). An extensive, high-quality, far-field acoustics data base was obtained for a rotor tip speed range of 645-771 ft/s. A 12-microphone, 500-ft radius semicircular array combined with two aircraft headings provided acoustic data over the full 360-deg azimuth about the aircraft with a resolution of 15 deg. Altitude variations provided data from near in-plane to 45 deg below the rotor tip path plane. Acoustic directivity characteristics in the lower hemisphere are explored through pressure time histories, narrow-band spectra, and contour plots. Directivity patterns were found to vary greatly with azimuth angle, especially in the forward quadrants. Sharp positive pressure pulses typical of blade-vortex interactions were found to propagate aft of the aircraft and were most intense at 45 deg below the rotor plane. Modest overall sound pressure levels were measured near in-plane indicating that thickness noise is not a major problem for this aircraft when operating in the hover mode with ATB. Rotor tip speed reductions reduced the average overall sound pressure level (dB (0.0002 dyne/cm(exp 2)) by nearly 8 dB in-plane, and 12.6 deg below the rotor plane.

Experimental study of the effect of drag reducing agent on pressure drop and thermal efficiency of an air cooler

NASA Astrophysics Data System (ADS)

Peyghambarzadeh, S. M.; Hashemabadi, S. H.; Saffarian, H.; Shekari, F.

2016-01-01

Effect of polymeric drag reduction agents (DRAs) on pressure drop and heat transfer was studied. Aqueous solutions of carboxy methyl cellulose were used inside an air-finned heat exchanger. Despite the previous studies which indicated the importance of drag reduction just in turbulent flow, results of this study in laminar flow indicated that the addition of DRA increases drag reduction, and decreases the overall heat transfer coefficient.

Changes in left ventricular function as determined by the multi-wire gamma camera at near presyncopal levels of lower body negative pressure

NASA Technical Reports Server (NTRS)

Pintner, R.; Fortney, S.; Mulvagh, S.; Lacy, J.

1992-01-01

At presyncopal levels of lower body negative pressure (LBNP), we have frequently observed electrocardiographic responses that may be due to changes in cardiac position and/or shape, but could be indicative of altered myocardial function. To further investigate this, we evaluated cardiac function using a nuclear imaging technique in 21 healthy subjects (17 men and 4 women) after 30 minutes of supine rest and near the end of a presyncopal-limited LBNP exposure (LBNP averaged 65 plus or minus 3 mmHg at injection). Cardiac first pass images were obtained with a Multi-Wire Gamma Camera following an intravenous bolus injection of 30-50 millicurries of Tantalum-178. Manual blood pressures and electrocardiograms were obtained throughout the 3 minute graded LBNP protocol. Between rest and injection during LBNP, heart rate increased (P less than 0.01) from 67 plus or minus 3 beats per minute to 99 plus or minus beats per minute, systolic blood pressure decreased (P less than 0.01) from 110 plus or minus 3 mmHg to 107 plus or minus 3 mmHg and left ventricular ejection fraction (EF) decreased (P less than 0.01) from 0.57 plus or minus 0.02 to 0.48 plus or minus 0.02. During LBNP, ST segment depression of at least 0.5 mm occurred in 7 subjects. Subjects with ST depression had greater reductions (P = 0.05) in EF than subjects without ST depression (0.15 plus or minus 0.07 versus 0.005 plus or minus 0.03), but also tolerated greater levels (P less than 0.05) of negative pressure (88 plus or minus mmHg versus 69 plus or minus 5 mmHg). There was a significant relationship between presyncopal LBNP level and EF (R(exp 2) = 0.50, P less than 0.05). Our findings suggest there may be a decrease in systolic myocardial function at high levels of LBNP.

Methylene blue prevents surgery-induced peritoneal adhesions but impairs the early phase of anastomotic wound healing

PubMed Central

Dinc, Soykan; Ozaslan, Cihangir; Kuru, Bekir; Karaca, Sefa; Ustun, Huseyin; Alagol, Haluk; Renda, Nurten; Oz, Murat

2006-01-01

Objectives Adhesion formation continues to be an important problem in gastrointestinal surgery. In recent years, methylene blue (MB) has been reported to be an effective agent for preventing peritoneal adhesions. However, its effects on the wound healing process are unknown. In the present study, we investigated the effects of MB on the early and late phases of anastomotic wound healing and on adhesion formation. Methods We randomly categorized 92 rats into 2 groups in bursting pressure measurements and 50 rats into 3 groups in the adhesion model. We divided the animals into saline-treated (n = 46) or MB-treated (n = 46) groups. Bursting pressures of the anastomoses were measured on postoperative days 3 and 7. In biochemical studies, tissue hydroxyproline levels, total nitrite/nitrate levels and nitric oxide synthase activity were measured on postoperative days 3 and 7. In the adhesion model, we randomly categorized rats into sham (n = 10), saline-treated (n = 20) and MB-treated (n = 20) groups, and the formation of intraperitoneal adhesions was scored on postoperative day 14. We compared the measurement of bursting pressure and biochemical measurements of tissue hydroxyproline levels, total nitrite/nitrate levels and nitric oxide synthase activity. Histopathological findings of specimens were presented. Results During the early phase of wound healing (postoperative day 3), bursting pressures, tissue hydroxyproline, total nitrite/nitrate levels and nitric oxide synthase activity in the MB-treated group were significantly lower than those of the saline-treated group. On postoperative day 7, there was no significant difference in these parameters between MB and saline-treated groups. In the adhesion model, MB caused a significant reduction in the formation of peritoneal adhesions. Conclusion MB prevents peritoneal adhesions but causes a significant impairment of anastomotic bursting pressure during the early phase of the wound healing process by its transient inhibitory effect on the nitric oxide pathway. PMID:17152569

A Computational-Experimental Development of Vortex Generator Use for a Transitioning S-Diffuser

NASA Technical Reports Server (NTRS)

Wendt, Bruce J.; Dudek, Julianne C.

1996-01-01

The development of an effective design strategy for surface-mounted vortex generator arrays in a subsonic diffuser is described in this report. This strategy uses the strengths of both computational and experimental analyses to determine beneficial vortex generator locations and sizes. A parabolized Navier-Stokes solver, RNS3D, was used to establish proper placement of the vortex generators for reduction in circumferential total pressure distortion. Experimental measurements were used to determine proper vortex generator sizing to minimize total pressure recovery losses associated with vortex generator device drag. The best result achieved a 59% reduction in the distortion index DC60, with a 0.3% reduction in total pressure recovery.

The change in NT-pro-BNP and post-PTMC echocardiography parameters in patients with mitral stenosis. A pilot study.

PubMed

Safi, Morteza; Bayat, Fariba; Ahmadi, Zahra; Shekarchizadeh, Masood; Khaheshi, Isa; Naderian, Mohammadreza

2017-06-01

The change in the level of NT-pro-BNP (N-terminal-pro-Brain Natriuretic Peptide) is now considered as a reflection of the hemodynamic alterations and its circulatory reductions reported early after successful PTMC (percutaneous transvenous mitral commissurotomy). The present study aims to assess the change in the level of NT-pro BNP following PTMC in patients with mitral stenosis and also to determine the association between circulatory NT-pro-BNP reduction and post-PTMC echocardiography parameters. Twenty five symptomatic consecutive patients with severe MS undergoing elective PTMC were prospectively enrolled. All patients underwent echocardiography before and also 24 to 48 hours after PTMC. Peripheral blood samples were taken for measurement of NT-pro-BNP before as well as 24 to 48 hours after PTMC. The patients were also classified in group with normal sinus rhythm or having atrial fibrillation (AF) based on their 12-lead electrocardiogram. It was shown a significant decrease in the parameters of PPG (Peak Pressure Gradient), MPG (Mean Pressure Gradient), PHT (Pressure Half Time), PAP (Pulmonary Arterial Pressure), LAV (Left Atrial Volume), and also a significant increase in MVA (Mitral Valve Area) RVS (Right Ventricular S velocity), and strains of lateral, septal, inferior and anterior walls of LA following PTMC. The mean LVEF remained unchanged after PTMC. The mean NT-pro-BNP before PTMC was 309.20 ± 17.97 pg/lit that significantly diminished after PTMC to 235.72 ± 22.46 pg/lit (p = 0.009). Among all echocardiography parameters, only MPG was positively associated with the change in NT-pro-BNP after PTMC. Comparing the change in echocardiography indices between the patients with normal rhythm and those with AF, lower change in PAP was shown in the group with AF. However, more change in the level of NT-pro-BNP after PTMC was shown in the patients with AF compared to those without this arrhythmia. PTMC procedure leads to reduce the level of NT-pro-BNP. The change in NT-pro-BNP is an indicator for change in MS severity indicated by decreasing MPG parameter. Lower change in PAP as well as higher change in NT-pro-BNP is predicted following PTMC in the group with AF compared to those with normal sinus rhythm.

Natrium dischargement from peripheral blood as a predominant factor influenced by the administration of banana (Musa paradisiaca) on elderly female hypertensive patient

NASA Astrophysics Data System (ADS)

Pramono, A.; Noriko, N.; Komara, S. B.

2017-04-01

Hypertension is more common in eldery female that triggered by diet and lifestyle changes. Bananas were not only useful for the food, but also for hypertension therapy and preserving life. Administration of bananas decreased blood pressure in hypertensive patients. This study aims to identify of factors that influenced by the administration of banana (Musa paradisiaca) on elderly female hypertensive patient. Twenty of eldery female patient were divided into 2 respondents group: control (11 patients) and treatment (9 patients). The treatment groups received banana twice a day during 2 weeks, but the control group didn’t. Here, we showed the administration of banana significantly decreased blood pressure on elderly female hypertensive patient (p = 0.00) in both systole and diastole. There was a significant decrease in sodium levels (p = 0.037) in the blood, but potassium levels remained the same. Erythrocyte sedimentation level (p = 0.136) and trombocyte count (p = 0.176) in treatment group, were not affected by banana administration. Taken together, banana administration on elderly female hypertensive patient decreased the blood pressure significantly, greatly affected by the natrium dischargement from the blood. Thus, our findings contribute to preliminary comprehension of banana effect on hypertension reduction.

Effects of combined pressure and temperature on enzymes related to quality of fruits and vegetables: from kinetic information to process engineering aspects.

PubMed

Ludikhuyze, L; Van Loey, A; Indrawati; Smout, C; Hendrickx, M

2003-01-01

Throughout the last decade, high pressure technology has been shown to offer great potential to the food processing and preservation industry in delivering safe and high quality products. Implementation of this new technology will be largely facilitated when a scientific basis to assess quantitatively the impact of high pressure processes on food safety and quality becomes available. Besides, quantitative data on the effects of pressure and temperature on safety and quality aspects of foods are indispensable for design and evaluation of optimal high pressure processes, i.e., processes resulting in maximal quality retention within the constraints of the required reduction of microbial load and enzyme activity. Indeed it has to be stressed that new technologies should deliver, apart from the promised quality improvement, an equivalent or preferably enhanced level of safety. The present paper will give an overview from a quantitative point of view of the combined effects of pressure and temperature on enzymes related to quality of fruits and vegetables. Complete kinetic characterization of the inactivation of the individual enzymes will be discussed, as well as the use of integrated kinetic information in process engineering.

Effects of a beta-adrenergic blocking agent timolol on intra ocular pressure responses induced by stimulation of cervical sympathetic nerve in the cat.

PubMed

Naito, A; Izumi, H; Karita, K; Tamai, M

2001-12-01

We clarified whether the intraocular pressure (IOP) response elicited by stimulation of the cervical sympathetic nerve (CSN) is influenced by changes in the baseline of IOP level and by beta-adrenergic blockade. The CSN was stimulated electrically for 30 seconds (10 V, 0.1-100 Hz, 2 milliseconds pulse duration) in urethane (100 mg/kg i.v.)-chloralose (50 mg/kg i.v.)-anesthetized, paralyzed cats. The IOP was monitored manometrically, and a controlled saline infusion was delivered into the anterior chamber to gradually increase IOP. CSN stimulation was delivered at the various baseline IOP levels so obtained. When required, a beta-adrenergic blocker timolol (2%) was delivered into the conjunctival cul-de-sac. The normal IOP in our cats was 25+/-3 mmHg. This value decreased transiently on CSN stimulation. The amplitude of this IOP response depended on stimulus frequency and the pre-stimulus baseline IOP level. Topical administration of timolol increased the IOP response to CSN stimulation at a given baseline level. These results suggest that beta-adrenergic blockade increases the alpha-adrenergic mediated-IOP reduction elicited by CSN stimulation at given baseline IOP level.

Priority issues for pressure injury research: An Australian consensus study.

PubMed

Haesler, Emily; Carville, Keryln; Haesler, Paul

2018-06-08

Pressure injuries are a significant health concern in all clinical settings. The current body of research on pressure injuries reported in the literature presents primarily low level evidence. The purpose of the current study was to identify and prioritize pressure injury research issues. The approach entailed evidence scoping and implementing a formal consensus process using a modified nominal group technique based on the Research and Development/University of California at Los Angeles appropriateness method. Sixteen Australian pressure injury experts participated in five consensus voting rounds in May to June 2015. From 60 initial research issues, the experts reached agreement that 26 issues are a priority for future pressure injury research. The highest priorities were strategies to assess skin and tissues, appropriate outcome measures for indicators of pressure injury healing and recurrence, heel pressure off-loading and shear reduction strategies, economic cost of pressure injuries and their management and effectiveness of skin moisturizers and barrier products. Developing a prioritized research agenda, informed by clinical and academic pressure injury experts, can assist in reducing the burden of pressure injuries by identifying topics of the highest need for further research. A web-based nominal group voting process was successful in engaging expert decision-making and has wide-reaching international appeal in facilitating cost-effective consensus methodologies. The priority list generated from this research is currently used in Australia to inform government investment in pressure injury research. © 2018 Wiley Periodicals, Inc.

Antihypertensive effects of continuous oral administration of nattokinase and its fragments in spontaneously hypertensive rats.

PubMed

Fujita, Mitsugu; Ohnishi, Katsunori; Takaoka, Shinsaku; Ogasawara, Kazuya; Fukuyama, Ryo; Nakamuta, Hiromichi

2011-01-01

To determine whether the antihypertensive effect of nattokinase is associated with the protease activity of this enzyme, we compared nattokinase with the fragments derived from nattokinase, which possessed no protease activity, in terms of the effect on hypertension in spontaneously hypertensive rats (SHR). In the continuous oral administration test, the groups were given a basic diet alone (control), the basic diet containing nattokinase (0.2, 2.6 mg/g diet) or the basic diet containing the fragments derived from nattokinase (0.2, 0.6 mg/g diet). The group fed the basic diet containing high-dosage nattokinase (2.6 mg/g diet) showed significant reductions in systolic blood pressure (SBP), diastolic blood pressure (DBP) and plasma fibrinogen level, compared with control group and no influence on activities of renin and angiotensin-converting enzyme (ACE, EC 3.4.15.1), and plasma angiotensin II level in the renin-angiotensin system. The treatment of the basic diet containing high-dosage fragments (0.6 mg/g diet) significantly decreased SBP, DBP and plasma angiotensin II level in plasma but the treatment did not influence on plasma fibrinogen level. These results suggest that nattokinase and its fragments are different from each other in the mechanism to reduce hypertension. Nattokinase, retained its protease activity after absorbance across the intestines, may decrease blood pressure through cleavage of fibrinogen in plasma. The fragments, which absorbed as nattokinase-degradation products, prevents the elevation of plasma angiotensin II level to suppress hypertension.

A blend of sesame oil and rice bran oil lowers blood pressure and improves the lipid profile in mild-to-moderate hypertensive patients.

PubMed

Devarajan, Sankar; Singh, Ravinder; Chatterjee, Biprabuddha; Zhang, Bo; Ali, Amanat

2016-01-01

Sesame oil and rice bran oil are known for their unsaturated fatty acids and antioxidants contents and have been reported to reduce the cardiovascular risk. To determine the effect of a blend of 20% unrefined cold-pressed lignans-rich sesame oil and 80% physically refined γ-oryzanol-rich rice bran oil (Vivo) as cooking oil in mild-to-moderate hypertensive patients. In this prospective, open-label dietary approach, 300 hypertensive patients and 100 normotensives were divided into groups as: (1) normotensives treated with sesame oil blend, (2) hypertensives treated with sesame oil blend, (3) hypertensives treated with nifedipine, a calcium channel blocker (20 mg/d), and (4) hypertensives receiving the combination of sesame oil blend and nifedipine (20 mg/d). Sesame oil blend was supplied to respective groups, and they were instructed to use it as the only cooking oil for 60 days. Resting blood pressure was measured at days 0, 15, 30, 45, and 60, whereas the fasting lipid profile was measured at days 0 and 60. Significant reduction in blood pressure (systolic, diastolic, and mean arterial) from days 0 to 15, 30, 45, and 60 were observed in hypertensives treated with sesame oil blend alone (P < .001), nifedipine alone (P < .001), and combination of sesame oil blend and nifedipine (P < .001). Sesame oil blend with nifedipine-treated group showed greatest reduction in blood pressure. Total cholesterol, low-density lipoprotein cholesterol, triglycerides, and non-high-density lipoprotein cholesterol levels reduced, whereas high-density lipoprotein cholesterol levels increased significantly only in hypertensives treated with sesame oil blend alone and the combination of sesame oil blend and nifedipine (P < .001). We demonstrate for the first time that using a blend of sesame oil and rice bran oil as cooking oil showed a significant antihypertensive and lipid-lowering action and had noteworthy additive effect with antihypertensive medication. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Stepping Up the Pressure: Arousal Can Be Associated with a Reduction in Male Aggression

PubMed Central

Ward, Andrew; Mann, Traci; Westling, Erika H.; Creswell, J. David; Ebert, Jeffrey P.; Wallaert, Matthew

2009-01-01

The attentional myopia model of behavioral control (Mann & Ward, 2007) was tested in an experiment investigating the relationship between physiological arousal and aggression. Drawing on previous work linking arousal and narrowed attentional focus, the model predicts that arousal will lead to behavior that is relatively disinhibited in situations in which promoting pressures to aggress are highly salient. In situations in which inhibitory pressures are more salient, the model predicts behavior that is relatively restrained. In the experiment, 81 male undergraduates delivered noise-blasts against a provoking confederate while experiencing either high or low levels of physiological arousal and, at the same time, being exposed to cues that served either to promote or inhibit aggression. In addition to supporting the predictions of the model, this experiment provided some of the first evidence for enhanced control of aggression under conditions of heightened physiological arousal. Implications for interventions designed to reduce aggression are discussed. PMID:18561301

Effects of Açai (Euterpe oleracea Mart.) berry preparation on metabolic parameters in a healthy overweight population: a pilot study.

PubMed

Udani, Jay K; Singh, Betsy B; Singh, Vijay J; Barrett, Marilyn L

2011-05-12

The purpose of this study was to evaluate the effect of açai fruit pulp on risk factors for metabolic disorders in overweight subjects. The açaí palm (Euterpe oleracea Mart.), which is native to South America, produces a small, black-purple fruit which is edible. The fruit has recently become popular as a functional food due to its antioxidant potential. Although several studies have been conducted in vitro and with animals, little is known about the potential health benefits in humans aside from an increase in plasma anti-oxidant capacity. Metabolic syndrome is a condition which is defined by a cluster of risk factors for cardiovascular disease and/or type-2 diabetes. Preliminary studies indicate that a reduction in reactive oxygen species can assist in the normalization of the metabolic pathways involved in this syndrome. This was an open label pilot study conducted with 10 overweight adults (BMI ≥ 25 kg/m² and ≤ 30 kg/m²) who took 100 g açai pulp twice daily for 1 month. The study endpoints included levels of fasting plasma glucose, insulin, cholesterol, triglycerides, exhaled (breath) nitric oxide metabolites (eNO) and plasma levels of high sensitivity C-reactive protein (hs-CRP). The response of blood glucose, blood pressure and eNO to a standardized meal was determined at baseline and following the 30 day treatment. Compared to baseline, there were reductions in fasting glucose and insulin levels following the 30 day treatment (both p < 0.02). There was also a reduction in total cholesterol (p = 0.03), as well as borderline significant reductions in LDL-cholesterol and the ratio of total cholesterol to HDL-cholesterol (both p = 0.051). Compared to baseline, treatment with açai ameliorated the post-prandial increase in plasma glucose following the standardized meal, measured as the area under the curve (p = 0.047). There was no effect on blood pressure, hs-CRP or eNO. In this uncontrolled pilot study, consumption of açai fruit pulp reduced levels of selected markers of metabolic disease risk in overweight adults, indicating that further studies are warranted.

Effects of Açai (Euterpe oleracea Mart.) berry preparation on metabolic parameters in a healthy overweight population: A pilot study

PubMed Central

2011-01-01

Background The purpose of this study was to evaluate the effect of açai fruit pulp on risk factors for metabolic disorders in overweight subjects. The açaí palm (Euterpe oleracea Mart.), which is native to South America, produces a small, black-purple fruit which is edible. The fruit has recently become popular as a functional food due to its antioxidant potential. Although several studies have been conducted in vitro and with animals, little is known about the potential health benefits in humans aside from an increase in plasma anti-oxidant capacity. Metabolic syndrome is a condition which is defined by a cluster of risk factors for cardiovascular disease and/or type-2 diabetes. Preliminary studies indicate that a reduction in reactive oxygen species can assist in the normalization of the metabolic pathways involved in this syndrome. Methods This was an open label pilot study conducted with 10 overweight adults (BMI ≥ 25 kg/m2 and ≤ 30 kg/m2) who took 100 g açai pulp twice daily for 1 month. The study endpoints included levels of fasting plasma glucose, insulin, cholesterol, triglycerides, exhaled (breath) nitric oxide metabolites (eNO) and plasma levels of high sensitivity C-reactive protein (hs-CRP). The response of blood glucose, blood pressure and eNO to a standardized meal was determined at baseline and following the 30 day treatment. Results Compared to baseline, there were reductions in fasting glucose and insulin levels following the 30 day treatment (both p < 0.02). There was also a reduction in total cholesterol (p = 0.03), as well as borderline significant reductions in LDL-cholesterol and the ratio of total cholesterol to HDL-cholesterol (both p = 0.051). Compared to baseline, treatment with açai ameliorated the post-prandial increase in plasma glucose following the standardized meal, measured as the area under the curve (p = 0.047). There was no effect on blood pressure, hs-CRP or eNO. Conclusion In this uncontrolled pilot study, consumption of açai fruit pulp reduced levels of selected markers of metabolic disease risk in overweight adults, indicating that further studies are warranted. PMID:21569436

Brain blood flow and cardiovascular responses to hot flashes in postmenopausal women

PubMed Central

Lucas, Rebekah A. I.; Ganio, Matthew S.; Pearson, James; Crandall, Craig G.

2012-01-01

Objective This study tested two related hypotheses: 1) that brain blood flow is reduced during the postmenopausal hot flash; and, 2) the magnitude of this reduction in brain blood flow is greater during hot flashes where blood pressure is reduced. Methods Eleven healthy, normotensive, postmenopausal women rested in a temperature-controlled laboratory (~25°C) for approximately 120 minutes while waiting for a hot flash to occur. The onset of a hot flash was objectively identified by an abrupt increase in sternal sweat rate (capacitance hygrometry). Middle cerebral artery blood velocity (MCAv, transcranial Doppler) and mean arterial pressure (Finometer®) were measured continuously. Each hot flash was divided into 8 equal segments and the segment with the largest reduction in MCAv and mean arterial pressure identified for each hot flash. Results Twenty-five hot flashes occurred during the experimental sessions (lasting 6.2 ± 2.8 min, 3 ± 1 hot flashes per participant). Seventy-six percent of hot flashes were accompanied by a clear reduction (greater than 5%) in brain blood flow. For all hot flashes, the average maximum decrease in MCAv was 12 ± 9% (7 ± 6 cm.s−1). This value did not correlate with corresponding changes in mean arterial pressure (R=0.36). Conclusion These findings demonstrate that hot flashes are often accompanied by clear reductions in brain blood flow that do not correspond with acute reductions in mean arterial blood pressure. PMID:23435027

Evaluation of SSME test data reduction methods

NASA Technical Reports Server (NTRS)

Santi, L. Michael

1994-01-01

Accurate prediction of hardware and flow characteristics within the Space Shuttle Main Engine (SSME) during transient and main-stage operation requires a significant integration of ground test data, flight experience, and computational models. The process of integrating SSME test measurements with physical model predictions is commonly referred to as data reduction. Uncertainties within both test measurements and simplified models of the SSME flow environment compound the data integration problem. The first objective of this effort was to establish an acceptability criterion for data reduction solutions. The second objective of this effort was to investigate the data reduction potential of the ROCETS (Rocket Engine Transient Simulation) simulation platform. A simplified ROCETS model of the SSME was obtained from the MSFC Performance Analysis Branch . This model was examined and tested for physical consistency. Two modules were constructed and added to the ROCETS library to independently check the mass and energy balances of selected engine subsystems including the low pressure fuel turbopump, the high pressure fuel turbopump, the low pressure oxidizer turbopump, the high pressure oxidizer turbopump, the fuel preburner, the oxidizer preburner, the main combustion chamber coolant circuit, and the nozzle coolant circuit. A sensitivity study was then conducted to determine the individual influences of forty-two hardware characteristics on fourteen high pressure region prediction variables as returned by the SSME ROCETS model.

Acoustic challenges of the A400M for active systems

NASA Astrophysics Data System (ADS)

Breitbach, Harald; Sachau, Delf; Böhme, Sten

2006-03-01

In some types of aircraft tonal interior noise with high sound pressure level (up to 110 dB(A)) occurs at low frequencies (f < 500 Hz). Typical examples are propeller driven aircraft, for which the excitation frequencies are given by the blade passage frequency (BPF) and its higher harmonics. The high tonal noise levels at these frequencies can occur due to the fact that the blades' profiles are only optimized in terms of aerodynamics. The acoustic properties are usually not taken into account. In order to obtain an acceptable interior noise level, and to guarantee both work-safety and comfort in the aircraft interiors, passive methods are commonly used - e.g. adding material with high damping or vibration absorbing qualities. Especially when low frequency noise has to be reduced, adding material results in a lot of unwanted additional weight. In order to avoid this extra weight, the concept of active noise reduction (ANR) and tunable vibration absorber systems (TVA), which focus on the unwanted tonal noise, are a good compromise of treating noise and the amount of additional weight in aircraft design. This paper briefly discusses two different possible methods to reduce the low frequency noise. The noise reduction of tuned vibration absorbers (TVA) mounted on the airframe are nowadays commonly used in propeller driven aircraft and can be predicted by vibroacoustic finite element calculations, which is described in this paper. In order to abide to industrial safety regulations, the noise level inside the semi closed loadmaster area (LMA) must be reduced down to a noise level, which is even 8 dB(A) below the specified cargo hold noise level. The paper describes also the phases of development of an ANR system that could be used to control the sound pressure level inside the LMA. The concept is verified by experimental investigations within a mock up of the LMA.

Tree water dynamics in a drying and warming world: Future tree water dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grossiord, Charlotte; Sevanto, Sanna; Borrego, Isaac

Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD), stomatal conductance (Gs), hydraulic conductivity (KL) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD formore » both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD, Gs and KL. Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs, FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions.« less

Tree water dynamics in a drying and warming world

DOE PAGES

Grossiord, Charlotte; Sevanto, Sanna Annika; Borrego, Isaac Anthony; ...

2017-05-26

Disentangling the relative impacts of precipitation reduction and vapour pressure deficit ( VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density ( FD), stomatal conductance ( Gs), hydraulic conductivity ( KL) and xylem anatomy in piñon pine ( Pinus edulis) and juniper ( Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced themore » sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD, Gs and KL. Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs, FD and KL took place to similar levels as under single stresses for both species. Here our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions.« less

Tree water dynamics in a drying and warming world

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grossiord, Charlotte; Sevanto, Sanna Annika; Borrego, Isaac Anthony

Disentangling the relative impacts of precipitation reduction and vapour pressure deficit ( VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density ( FD), stomatal conductance ( Gs), hydraulic conductivity ( KL) and xylem anatomy in piñon pine ( Pinus edulis) and juniper ( Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced themore » sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD, Gs and KL. Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs, FD and KL took place to similar levels as under single stresses for both species. Here our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions.« less

Pressure drop reduction and heat transfer deterioration of slush nitrogen in triangular and circular pipe flows

NASA Astrophysics Data System (ADS)

Ohira, Katsuhide; Kurose, Kizuku; Okuyama, Jun; Saito, Yutaro; Takahashi, Koichi

2017-01-01

Slush fluids such as slush hydrogen and slush nitrogen are characterized by superior properties as functional thermal fluids due to their density and heat of fusion. In addition to allowing efficient hydrogen transport and storage, slush hydrogen can serve as a refrigerant for high-temperature superconducting (HTS) equipment using MgB2, with the potential for synergistic effects. In this study, pressure drop reduction and heat transfer deterioration experiments were performed on slush nitrogen flowing in a horizontal triangular pipe with sides of 20 mm under the conditions of three different cross-sectional orientations. Experimental conditions consisted of flow velocity (0.3-4.2 m/s), solid fraction (0-25 wt.%), and heat flux (0, 10, and 20 kW/m2). Pressure drop reduction became apparent at flow velocities exceeding about 1.3-1.8 m/s, representing a maximum amount of reduction of 16-19% in comparison with liquid nitrogen, regardless of heating. Heat transfer deterioration was seen at flow velocities of over 1.2-1.8 m/s, for a maximum amount of deterioration of 13-16%. The authors of the current study compared the results for pressure drop reduction and heat transfer deterioration in triangular pipe with those obtained previously for circular and square pipes, clarifying differences in flow and heat transfer properties. Also, a correlation equation was obtained between the slush Reynolds number and the pipe friction factor, which is important in the estimation of pressure drop in unheated triangular pipe. Furthermore, a second correlation equation was derived between the modified slush Reynolds number and the pipe friction factor, enabling the integrated prediction of pressure drop in both unheated triangular and circular pipes.

Effect of Leaf Water Potential on Internal Humidity and CO 2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure

DOE PAGES

Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia; ...

2017-02-06

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flatmore » surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2, thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Here, our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. Lastly, the omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange measurements. Manufactures of leaf gas exchange measurement systems should incorporate leaf water potentials in measurement set-ups.« less

Effect of Leaf Water Potential on Internal Humidity and CO 2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flatmore » surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2, thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Here, our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. Lastly, the omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange measurements. Manufactures of leaf gas exchange measurement systems should incorporate leaf water potentials in measurement set-ups.« less

Effect of Leaf Water Potential on Internal Humidity and CO2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure

PubMed Central

Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia; Salmon, Yann; Nikinmaa, Eero; Hari, Pertti; Hölttä, Teemu

2017-01-01

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flat surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO2, thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Our results indicate that the reduction in vapor pressures of water and CO2 could enhance plant water use efficiency up to about 10% at a leaf water potential of −2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. The omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO2 concentration based on leaf gas exchange measurements. Manufactures of leaf gas exchange measurement systems should incorporate leaf water potentials in measurement set-ups. PMID:28220128

Effect of Leaf Water Potential on Internal Humidity and CO2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure.

PubMed

Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia; Salmon, Yann; Nikinmaa, Eero; Hari, Pertti; Hölttä, Teemu

2017-01-01

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flat surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2 , thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. The omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange measurements. Manufactures of leaf gas exchange measurement systems should incorporate leaf water potentials in measurement set-ups.

Advanced Acid Gas Separation Technology for the Utilization of Low Rank Coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kloosterman, Jeff

2012-12-31

Air Products has developed a potentially ground-breaking technology – Sour Pressure Swing Adsorption (PSA) – to replace the solvent-based acid gas removal (AGR) systems currently employed to separate sulfur containing species, along with CO{sub 2} and other impurities, from gasifier syngas streams. The Sour PSA technology is based on adsorption processes that utilize pressure swing or temperature swing regeneration methods. Sour PSA technology has already been shown with higher rank coals to provide a significant reduction in the cost of CO{sub 2} capture for power generation, which should translate to a reduction in cost of electricity (COE), compared to baselinemore » CO{sub 2} capture plant design. The objective of this project is to test the performance and capability of the adsorbents in handling tar and other impurities using a gaseous mixture generated from the gasification of lower rank, lignite coal. The results of this testing are used to generate a high-level pilot process design, and to prepare a techno-economic assessment evaluating the applicability of the technology to plants utilizing these coals.« less

Oleic acid content is responsible for the reduction in blood pressure induced by olive oil.

PubMed

Terés, S; Barceló-Coblijn, G; Benet, M; Alvarez, R; Bressani, R; Halver, J E; Escribá, P V

2008-09-16

Numerous studies have shown that high olive oil intake reduces blood pressure (BP). These positive effects of olive oil have frequently been ascribed to its minor components, such as alpha-tocopherol, polyphenols, and other phenolic compounds that are not present in other oils. However, in this study we demonstrate that the hypotensive effect of olive oil is caused by its high oleic acid (OA) content (approximately 70-80%). We propose that olive oil intake increases OA levels in membranes, which regulates membrane lipid structure (H(II) phase propensity) in such a way as to control G protein-mediated signaling, causing a reduction in BP. This effect is in part caused by its regulatory action on G protein-associated cascades that regulate adenylyl cyclase and phospholipase C. In turn, the OA analogues, elaidic and stearic acids, had no hypotensive activity, indicating that the molecular mechanisms that link membrane lipid structure and BP regulation are very specific. Similarly, soybean oil (with low OA content) did not reduce BP. This study demonstrates that olive oil induces its hypotensive effects through the action of OA.

Mechanism study on pressure fluctuation of pump-turbine runner with large blade lean angle

NASA Astrophysics Data System (ADS)

Yulin, Fan; Xuhe, Wang; Baoshan, Zhu; Dongyue, Zhou; Xijun, Zhou

2016-11-01

Excessive pressure fluctuations in the vaneless space can cause mechanical vibration and even mechanical failures in pump-turbine operation. Mechanism studies on the pressure fluctuations and optimization design of blade geometry to reduce the pressure fluctuations have important significance in industrial production. In the present paper, two pump-turbine runners with big positive and negative blade lean angle were designed by using a multiobjective design strategy. Model test showed that the runner with negative blade lean angle not only had better power performance, but also had lower pressure fluctuation than the runner with positive blade lean angle. In order to figure out the mechanism of pressure fluctuation reduction in the vaneless;jik8space, full passage model for both runners were built and transient CFD computations were conducted to simulate the flow states inside the channel. Detailed flow field analyses indicated that the difference of low-pressure area in the trailing edge of blade pressure side were the main causes of pressure fluctuation reduction in the vaneless space.

The impact of parity on life course blood pressure trajectories: the HUNT study in Norway.

PubMed

Haug, Eirin B; Horn, Julie; Markovitz, Amanda Rose; Fraser, Abigail; Macdonald-Wallis, Corrie; Tilling, Kate; Romundstad, Pål Richard; Rich-Edwards, Janet Wilson; Åsvold, Bjørn Olav

2018-01-24

The drop in blood pressure during pregnancy may persist postpartum, but the impact of pregnancy on blood pressure across the life course is not known. In this study we examined blood pressure trajectories for women in the years preceding and following pregnancy and compared life course trajectories of blood pressure for parous and nulliparous women. We linked information on all women who participated in the population-based, longitudinal HUNT Study, Norway with pregnancy information from the Medical Birth Registry of Norway. A total of 23,438 women were included with up to 3 blood pressure measurements per woman. Blood pressure trajectories were compared using a mixed effects linear spline model. Before first pregnancy, women who later gave birth had similar mean blood pressure to women who never gave birth. Women who delivered experienced a drop after their first birth of - 3.32 mmHg (95% CI, - 3.93, - 2.71) and - 1.98 mmHg (95% CI, - 2.43, - 1.53) in systolic and diastolic blood pressure, respectively. Subsequent pregnancies were associated with smaller reductions. These pregnancy-related reductions in blood pressure led to persistent differences in mean blood pressure, and at age 50, parous women still had lower systolic (- 1.93 mmHg; 95% CI, - 3.33, - 0.53) and diastolic (- 1.36 mmHg; 95% CI, - 2.26, - 0.46) blood pressure compared to nulliparous women. The findings suggest that the first pregnancy and, to a lesser extent, successive pregnancies are associated with lasting and clinically relevant reductions in systolic and diastolic blood pressure.

The influence of tobacco smoking on the relationship between pressure and flow in the middle cerebral artery in humans.

PubMed

Peebles, Karen C; Horsman, Helen; Tzeng, Yu-Chieh

2013-01-01

Cigarette smoking is associated with an increased risk of stroke but the mechanism is unclear. The study examined whether acute and chronic cigarette smoking alters the dynamic relationship between blood pressure and cerebral blood flow. We hypothesised that acute and chronic smoking would result in a cerebral circulation that was less capable of buffering against dynamic fluctuations in blood pressure. Further, these changes would be accompanied by a reduction in baroreflex sensitivity, which is reduced after smoking (acute smoking). We recruited 17 non-smokers and 15 habitual smokers (13 ± 5 pack years). Continuous measurements of mean cerebral blood flow velocity (transcranial Doppler ultrasound), blood pressure (finger photoplethysmography) and heart rate enabled transfer function analysis of the dynamic relationship between pressure and flow (gain, normalised gain, phase and coherence) and baroreflex sensitivity during supine rest before and after smoking a single cigarette (acute smoking). There were no between-group differences in gain, phase or coherence before acute smoking. However, both groups showed a reduction in gain and coherence, associated with a reduction in baroreflex sensitivity, and increase in phase after acute smoking. Contrary to our hypothesis, these findings suggest that in the face of a reduction in baroreflex sensitivity acute smoking may potentially improve the ability of the cerebral circulation to buffer against changes in blood pressure. However, chronic smoking did not alter the dynamic relationship between blood pressure and cerebral blood flow velocity. These results have implications on understanding mechanisms for attenuating stroke risk.

The efficacy of novel anatomical sites for the assessment of muscle oxygenation during central hypovolemia.

PubMed

Sprick, Justin D; Soller, Babs R; Rickards, Caroline A

2016-11-01

Muscle tissue oxygenation (SmO 2 ) can track central blood volume loss associated with hemorrhage. Traditional peripheral measurement sites (e.g., forearm) may not be practical due to excessive movement or injury (e.g., amputation). The aim of this study was to evaluate the efficacy of three novel anatomical sites for the assessment of SmO 2 under progressive central hypovolemia. 10 male volunteers were exposed to stepwise prone lower body negative pressure to decrease central blood volume, while SmO 2 was assessed at four sites-the traditional site of the flexor carpi ulnaris (ARM), and three novel sites not previously investigated during lower body negative pressure, the deltoid, latissimus dorsi, and trapezius. SmO 2 at the novel sites was compared to the ARM sensor and to stroke volume responses. A reduction in SmO 2 was detected by the ARM sensor at the first level of lower body negative pressure (-15 mmHg; P = 0.007), and at -30 (the deltoid), -45 (latissimus dorsi), and -60 mmHg lower body negative pressure (trapezius) at the novel sites (P ≤ 0.04). SmO 2 responses at all novel sites were correlated with responses at the ARM (R ≥ 0.89), and tracked the reduction in stroke volume (R ≥ 0.87); the latissimus dorsi site exhibited the strongest linear correlations (R ≥ 0.96). Of the novel sensor sites, the latissimus dorsi exhibited the strongest linear associations with SmO 2 at the ARM, and with reductions in central blood volume. These findings have important implications for detection of hemorrhage in austere environments (e.g., combat) when use of a peripheral sensor may not be ideal, and may facilitate incorporation of these sensors into uniforms. © 2016 by the Society for Experimental Biology and Medicine.

A Wireless Lingual Feedback Device to Reduce Overpressures in Seated Posture: A Feasibility Study

PubMed Central

Chenu, Olivier; Vuillerme, Nicolas; Demongeot, Jacques; Payan, Yohan

2009-01-01

Background Pressure sores are localized injuries to the skin and underlying tissues and are mainly resulting from overpressure. Paraplegic peoples are particularly subjects to pressure sores because of long-time seated postures and sensory deprivation at the lower limbs. Methodology/Principal Findings Here we report outcomes of a feasibility trial involving a biofeedback system aimed at reducing buttock overpressure whilst an individual is seated. The system consists of (1) pressure sensors, (2) a laptop coupling sensors and actuator (3) a wireless Tongue Display Unit (TDU) consisting of a circuit embedded in a dental retainer with electrodes put in contact with the tongue. The principle consists in (1) detecting overpressures in people who are seated over long periods of time, (2) estimating a postural change that could reduce these overpressures and (3) communicating this change through directional information transmitted by the TDU.Twenty-four healthy subjects voluntarily participated in this study. Twelve healthy subjects initially formed the experimental group (EG) and were seated on a chair with the wireless TDU inside their mouth. They were asked to follow TDU orders that were randomly spread throughout the session. They were evaluated during two experimental sessions during which 20 electro-stimulations were sent. Twelve other subjects, added retrospectively, formed the control group (CG). These subjects participated in one session of the same experiment without any biofeedback.Three dependent variables were computed: (1) the ability of subjects to reach target posture (EG versus CG), (2) high pressure reductions after a biofeedback (EG versus CG) and (3) the level of these reductions relative to their initial values (EG only). Results show (1) that EG reached target postures in 90.2% of the trials, against 5,3% in the CG, (2) a significant reduction in overpressures in the EG compared to the CG and (3), for the EG, that the higher the initial pressures were, the more they were decreased. Conclusions/Significance The findings suggest that, in this trial, subjects were able to use a tongue tactile feedback system to reduce buttock overpressure while seated. Further evaluation of this system on paraplegic subjects remains to be done. PMID:19888336

[C-reactive protein changes with antihypertensive and statin treatment].

PubMed

Rodilla, Enrique; Gómez-Belda, Ana; Costa, José A; Aragó, Miriam; Miralles, Amparo; González, Carmen; Pascual, José M

2005-10-29

The aim of this study was to evaluate the modifications of high sensitivity C-reactive protein (CRP) with antihypertensive and statin treatment in a hypertensive population with a wide range of coronary risks (CR). Retrospective follow-up study in 665 hypertensive patients: 556 (52% male) without dyslipidemia and CR (Framingham at 10 years) of 8.3 (7.6) as a control group (C) and 109 (61% male) with dyslipidemia and CR of 13.1 (8.8) who were treated with statins (T). Statins treatment was established according to NCEP-ATP-III. In both groups, the antihypertensive treatment was optimized in order to achieve blood pressure (BP) control (< 140/90 mmHg). A lipid profile and high sensitivity CRP (analyzed by nephelometry) was performed at the beginning and at the end of follow up [14.3 (3.6) months]. CRP levels were reduced in the T group -0.17 (0.2) mg/L vs. 0.14 (0.09) mg/L (p = 0.003, Mann-Whitney) in C. The lessening of CRP was not related to the reduction of lipids levels: total cholesterol (r = 0.06; p = 0.49), LDL-C (r = 0.11; p = 0.24), triglycerides (r = -0.02; p = 0.81) (Spearman), or to the reduction of systolic BP (r = -0.07; p = 0.44) and diastolic BP (r = -0.121; p = 0.21). The T group was treated with more antihypertensive drugs than C (2.2 [2.3] vs. 2.5 [1.2]; p = 0.02). Patients treated with ECA inhibitors or angiotensin II antagonist showed a tendency to decreasing the CRP levels more (p = 0.08). In hypertensive populations, statins induce a reduction of CRP levels. The reduction is not related to the lowering of lipids levels or BP values. The effect of statins on the reduction of CRP in hypertensive patients is not related to the lowering of lipids or BP.

Combined analysis of trabectome and phaco-trabectome outcomes by glaucoma severity

PubMed Central

Bussel, Igor I.; Loewen, Ralitsa T.; Parikh, Hardik; Loewen, Nils A.

2016-01-01

Prior glaucoma severity staging systems were mostly concerned with visual field function and retinal nerve fiber layer, but did not include intraocular pressure or medications to capture resistance to treatment. We recently introduced a simple index that combines pressure, medications, and visual field damage and applied it to stratify outcomes of trabectome surgery. In the analysis presented here, we combined data of trabectome alone and trabectome with same session cataract surgery to increase testing power and chances of effect discovery. This microincisional glaucoma surgery removes the primary resistance to outflow in glaucoma, the trabecular meshwork, and has been mostly used in mild glaucoma. Traditional glaucoma surgeries have a relatively high complication rate and have been reserved for more advanced disease stages. In the analysis presented here we include our data of trabectome combined with cataract surgery. This is a common practice pattern as both occur in the same age group with increasing frequency. For patients in higher glaucoma index (GI) groups, the intraocular pressure (IOP) reduction was 2.34+/-0.19 mmHg more than those in a GI group one level lower while holding everything else constant. Those who had undergone trabectome combined with phacoemulsification had an IOP reduction that was 1.29+/-0.39 mmHg less compared to those with trabectome alone. No statistically significant difference was found between genders and age groups while holding everything else constant. Hispanics had a 3.81+/-1.08 mmHg greater IOP reduction. Pseudoexfoliation and steroid glaucoma patients had an IOP reduction that was greater by 2.91+/-0.56 and 3.86+/-0.81 mmHg, respectively, than those with primary open angle glaucoma. These results suggest a role for trabectome-mediated ab interno trabeculectomy beyond mild forms of glaucoma. Additionally, the multifactorial glaucoma index demonstrates a role in staging patients when comparing glaucoma surgical modalities. PMID:27239278

Numerical experiment on the flow field properties of a blunted body with a counterflowing jet in supersonic flows

NASA Astrophysics Data System (ADS)

Huang, Wei; Zhang, Rui-Rui; Yan, Li; Ou, Min; Moradi, R.

2018-06-01

The prediction of the drag and heat flux reduction characteristics is a very important issue in the conceptual design phase of the hypersonic vehicle. In this paper, the flow field properties around a blunted body with a counterflowing jet in the supersonic flow with the freestream Mach number being 3.98 were investigated numerically, and they are obtained by means of the two-dimensional axisymmetric Reynolds-averaged Navier-Stokes (RANS) equations coupled with the two equation standard k-ε turbulence model. The surface Stanton number distributions, as well as the surface static pressures, were extracted from the flow field structures in order to evaluate the drag and heat flux reduction characteristics. Further, the influences of the jet pressure ratio and the jet Mach number on the drag and heat flux reduction were analyzed based on the detailed code validation and grid independency analysis process. The obtained results show that the flow cell Reynolds number has a great impact on the heat flux prediction, and its best value is 5.0 for the case studied in the current study. However, the flow cell Reynolds number and the grid scale both have only a slight impact on the prediction of the surface static pressure distribution, as well as the turbulence model. The larger jet pressure ratio is beneficial for the drag and heat flux reduction, and the smaller jet Mach number is beneficial for the heat flux reduction. Further, the long penetration mode is beneficial for the drag reduction, but it is not beneficial for the heat flux reduction.

Mechanism of Headward Fluid Shift During Exposure To Microgravity

NASA Technical Reports Server (NTRS)

Hargens, Alan R.; Parazynski, Scott E.; Watenpaugh, Donald E.; Aratow, Michael; Murthy, Gita; Kawai, Yasuaki

1994-01-01

A prominent feature of early cardiovascular adaptation to the microgravity of space flight is a shift of blood and tissue fluid from the lower body to the upper body. Symptoms of this fluid shift include facial edema, nasal congestion, and headache. Normally on Earth, the human body is exposed to hydrostatic (gravitational) blood pressure gradients during upright posture. In this posture, mean arterial pressures at head, heart, and foot levels are approximately 70, 100, and 200 mm Hg, respectively. Theoretically, all hydrostatic pressures within arteries and veins are lost during exposure to microgravity so that mean arterial pressure in all regions of the body is uniform and approximately equal to that at heart level (100 mm Hg). Acute studies of 60 head-down tilt (simulated microgravity on Earth) indicate that facial edema is caused by: 1) elevation of capillary blood pressure from 28 to 34 mm Hg, 2) reduction of blood colloid osmotic pressure 22 to 18 mm Hg, and 3) 50% increase of blood perfusion in tissues of the head. Furthermore, as compared to microvasculature in the feet, microvessels of the head have a low capacity to constrict and diminish local perfusion. Elevation of blood and tissue fluid pressures/flow in the head may also explain the higher headward bone density associated with long-term head-down tilt. These mechanistic studies of head-down tilt, along with a better understanding of the relative stresses involved with upright posture and lower body negative pressure, have facilitated development of physiologic countermeasures to maintain astronaut health during microgravity. Presently no exercise hardware is available to provide a blood pressure gradient from head to feet in space. However, recent studies in our laboratory suggest that treadmill exercise within lower body negative pressure provides equivalent or greater physiologic stress as compared to similar upright exercise on Earth.

Passive continuous positive airway pressure ventilation during cardiopulmonary resuscitation: a randomized cross-over manikin simulation study.

PubMed

Winkler, Bernd E; Muellenbach, Ralf M; Wurmb, Thomas; Struck, Manuel F; Roewer, Norbert; Kranke, Peter

2017-02-01

While controlled ventilation is most frequently used during cardiopulmonary resuscitation (CPR), the application of continuous positive airway pressure (CPAP) and passive ventilation of the lung synchronously with chest compressions and decompressions might represent a promising alternative approach. One benefit of CPAP during CPR is the reduction of peak airway pressures and therefore a potential enhancement in haemodynamics. We therefore evaluated the tidal volumes and airway pressures achieved during CPAP-CPR. During CPR with the LUCAS™ 2 compression device, a manikin model was passively ventilated at CPAP levels of 5, 10, 20 and 30 hPa with the Boussignac tracheal tube and the ventilators Evita ® V500, Medumat ® Transport, Oxylator ® EMX, Oxylog ® 2000, Oxylog ® 3000, Primus ® and Servo ® -i as well as the Wenoll ® diver rescue system. Tidal volumes and airway pressures during CPAP-CPR were recorded and analyzed. Tidal volumes during CPAP-CPR were higher than during compression-only CPR without positive airway pressure. The passively generated tidal volumes increased with increasing CPAP levels and were significantly influenced by the ventilators used. During ventilation at 20 hPa CPAP via a tracheal tube, the mean tidal volumes ranged from 125 ml (Medumat ® ) to 309 ml (Wenoll ® ) and the peak airway pressures from 23 hPa (Primus ® ) to 49 hPa (Oxylog ® 3000). Transport ventilators generated lower tidal volumes than intensive care ventilators or closed-circuit systems. Peak airway pressures during CPAP-CPR were lower than those during controlled ventilation CPR reported in literature. High peak airway pressures are known to limit the applicability of ventilation via facemask or via supraglottic airway devices and may adversely affect haemodynamics. Hence, the application of ventilators generating high tidal volumes with low peak airway pressures appears desirable during CPAP-CPR. The limited CPAP-CPR capabilities of transport ventilators in our study might be prerequisite for future developments of transport ventilators.

Cabin noise and weight reduction program for the Gulfstream G200

NASA Astrophysics Data System (ADS)

Barton, C. Kearney

2002-11-01

This paper describes the approach and logic involved in a cabin noise and weight reduction program for an existing aircraft that was already in service with a pre-existing insulation package. The aircraft, a Gulfstream G200, was formally an IAI Galaxy, and the program was purchased from IAI in 2001. The approach was to investigate every aspect of the aircraft that could be a factor for cabin noise. This included such items as engine mounting and balancing criteria, the hydraulic system, the pressurization and air-conditioning system, the outflow valve, the interior shell and mounting system, antennae and other hull protuberances, as well as the insulation package. Each of these items was evaluated as potential candidates for noise and weight control modifications. Although the program is still ongoing, the results to date include a 175-lb weight savings and a 5-dB reduction in the cabin average Speech Interference Level (SIL).

Active Noise Control of Radiated Noise from Jets Originating NASA

NASA Technical Reports Server (NTRS)

Doty, Michael J.; Fuller, Christopher R.; Schiller, Noah H.; Turner, Travis L.

2013-01-01

The reduction of jet noise using a closed-loop active noise control system with highbandwidth active chevrons was investigated. The high frequency energy introduced by piezoelectrically-driven chevrons was demonstrated to achieve a broadband reduction of jet noise, presumably due to the suppression of large-scale turbulence. For a nozzle with one active chevron, benefits of up to 0.8 dB overall sound pressure level (OASPL) were observed compared to a static chevron nozzle near the maximum noise emission angle, and benefits of up to 1.9 dB OASPL were observed compared to a baseline nozzle with no chevrons. The closed-loop actuation system was able to effectively reduce noise at select frequencies by 1-3 dB. However, integrated OASPL did not indicate further reduction beyond the open-loop benefits, most likely due to the preliminary controller design, which was focused on narrowband performance.

Vascular and metabolic effects of ezetimibe combined with simvastatin in patients with hypercholesterolemia.

PubMed

Koh, Kwang Kon; Oh, Pyung Chun; Sakuma, Ichiro; Kim, Eun Young; Lee, Yonghee; Hayashi, Toshio; Han, Seung Hwan; Park, Yae Min; Shin, Eak Kyun

2015-11-15

Ezetimibe demonstrates decreasing visceral fat and improving insulin sensitivity (IS) in animals and humans. We first reported that simvastatin dose-dependently worsens insulin sensitivity. Whether ezetimibe may compensate untoward effects of simvastatin, depending on dosages of simvastatin has not been investigated in patients with hypercholesterolemia, compared with simvastatin alone. This was a randomized, single-blind, placebo-controlled, parallel study. Fifty-one in each group were given placebo, ezetimibe 10mg combined with simvastatin 10mg (Vyto10), ezetimibe 10mg combined with simvastatin 20mg (Vyto20), or simvastatin 20mg alone (Simva20) daily for 2months. Placebo, Vyto10, Vyto20, and Simva20 improved flow-mediated dilation relative to baseline measurements. Placebo therapy did not significantly change insulin and IS and adiponectin levels and visceral fat area (VFA) and VFA/subcutaneous fat area (SFA) relative to baseline measurements. Vyto10 therapy significantly decreased CRP and insulin levels and increased adiponectin levels and IS, and reduced VFA, VFA/SFA, and blood pressure. Vyto20 therapy did not significantly change insulin levels and IS and adiponectin levels but significantly reduced CRP levels and VFA, VFA/SFA, and blood pressure. Simva20 therapy significantly decreased adiponectin levels and IS but did not significantly change VFA, VFA/SFA, and blood pressure. Of note, these different effects of each therapy were significant by ANOVA. Vyto10, Vyto20, and Simva20 showed significant reduction of LDL cholesterol levels and improvement of flow-mediated dilation in patients with hypercholesterolemia. However, Vyto10, Vyto20, and Simva20 showed significantly differential metabolic effects, depending on dosages of simvastatin. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Beta-erythropoietin effects on ventricular remodeling, left and right systolic function, pulmonary pressure, and hospitalizations in patients affected with heart failure and anemia.

PubMed

Palazzuoli, Alberto; Silverberg, Donald S; Calabrò, Anna; Spinelli, Tommaso; Quatrini, Ilaria; Campagna, Maria S; Franci, Beatrice; Nuti, Ranuccio

2009-06-01

Anemia in heart failure is related to advanced New York Heart Association classes, severe systolic dysfunction, and reduced exercise tolerance. Although anemia is frequently found in congestive heart failure (CHF), little is known about the effect of its' correction with erythropoietin (EPO) on cardiac structure and function. The present study examines, in patients with advanced CHF and anemia, the effects of beta-EPO on left ventricular volumes, left ventricular ejection fraction (LVEF), left and right longitudinal function mitral anular plane systolic excursion (MAPSE), tricuspid anular plane excursion (TAPSE), and pulmonary artery pressures in 58 patients during 1-year follow-up in a double-blind controlled study of correction of anemia with subcutaneous beta-EPO. Echocardiographic evaluation, B-Type natriuretic peptide (BNP) levels, and hematological parameters are reported at 4 and 12 months. The patients in group A after 4 months of follow-up period demonstrated an increase in LVEF and MAPSE (P < 0.05 and P < 0.01, respectively) with left ventricular systolic volume reduction (P < 0.02) with respect to baseline and controls. After 12 months, results regarding left ventricular systolic volume LVEF and MAPSE persisted (P < 0.001). In addition, TAPSE increased and pulmonary artery pressures fell significantly in group A (P < 0.01). All these changes occurred together with a significant BNP reduction and significant hemoglobin increase in the treated group. Therefore, we revealed a reduced hospitalization rate in treated patients with respect to the controls (25% in treated vs. 54% in controls). In patients with anemia and CHF, correction of anemia with beta-EPO and oral iron over 1 year leads to an improvement in left and right ventricular systolic function by reducing cardiac remodeling, BNP levels, and hospitalization rate.

Effects of exercise training on cardiovascular adrenergic system.

PubMed

Leosco, Dario; Parisi, Valentina; Femminella, Grazia D; Formisano, Roberto; Petraglia, Laura; Allocca, Elena; Bonaduce, Domenico

2013-11-28

In heart failure (HF), exercise has been shown to modulate cardiac sympathetic hyperactivation which is one of the earliest features of neurohormonal derangement in this syndrome and correlates with adverse outcome. An important molecular alteration related to chronic sympathetic overstimulation in HF is represented by cardiac β-adrenergic receptor (β-AR) dysfunction. It has been demonstrated that exercise reverses β-AR dysfunction by restoring cardiac receptor membrane density and G-protein-dependent adenylyl cyclase activation. In particular, several evidence indicate that exercise reduces levels of cardiac G-protein coupled receptor kinase-2 (GRK2) which is known to be involved in both β1-AR and β2-AR dysregulation in HF. Similar alterations of β-AR system have been described also in the senescent heart. It has also been demonstrated that exercise training restores adrenal GRK2/α-2AR/catecholamine (CA) production axis. At vascular level, exercise shows a therapeutic effect on age-related impairment of vascular reactivity to adrenergic stimulation and restores β-AR-dependent vasodilatation by increasing vascular β-AR responsiveness and reducing endothelial GRK2 activity. Sympathetic nervous system overdrive is thought to account for >50% of all cases of hypertension and a lack of balance between parasympathetic and sympathetic modulation has been observed in hypertensive subjects. Non-pharmacological, lifestyle interventions have been associated with reductions in SNS overactivity and blood pressure in hypertension. Several evidence have highlighted the blood pressure lowering effects of aerobic endurance exercise in patients with hypertension and the significant reduction in sympathetic neural activity has been reported as one of the main mechanisms explaining the favorable effects of exercise on blood pressure control.

Respiratory-Induced Haemodynamic Changes: A Contributing Factor to IVC Filter Penetration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laborda, Alicia, E-mail: alaborda@unizar.es; Kuo, William T., E-mail: wkuo@stanford.edu; Ioakeim, Ignatios, E-mail: ignacio.ioakim@hotmail.es

2015-10-15

PurposeThe purpose of the study is to evaluate the influence of respiratory-induced vena caval hemodynamic changes on filter migration/penetration.Materials and MethodsAfter placement of either a Gunther Tulip or Celect IVC filter, 101 consecutive patients scheduled for filter retrieval were prospectively enrolled in this study. Pre-retrieval CT scans were used to assess filter complications and to calculate cross-sectional area in three locations: at level of filter strut fixation, 3 cm above and 3 cm below. A 3D finite element simulation was constructed on these data and direct IVC pressure was recorded during filter retrieval. Cross-sectional areas and pressures of the vena cava weremore » measured during neutral breathing and in Valsalva maneuver and identified filter complications were recorded. A statistical analysis of these variables was then performed.ResultsDuring Valsalva maneuvers, a 60 % decrease of the IVC cross-sectional area and a fivefold increase in the IVC pressure were identified (p < 0.001). There was a statistically significant difference in the reduction of the cross-sectional area at the filter strut level (p < 0.001) in patient with filter penetration. Difficulty in filter retrieval was higher in penetrated or tilted filters (p < 0.001; p = 0.005). 3D computational models showed significant IVC deformation around the filter during Valsalva maneuver.ConclusionCaval morphology and hemodynamics are clearly affected by Valsalva maneuvers. A physiological reduction of IVC cross-sectional area is associated with higher risk of filter penetration, despite short dwell times. Physiologic data should be used to improve future filter designs to remain safely implanted over longer dwell times.« less

Synergistic effect of high hydrostatic pressure and natural antimicrobials on inactivation kinetics of Bacillus cereus in a liquid whole egg and skim milk mixed beverage.

PubMed

Pina-Pérez, Maria Consuelo; Silva-Angulo, Angela B; Muguerza-Marquínez, Begoña; Aliaga, D Rodrigo; López, Antonio Martínez

2009-01-01

An in-depth study was conducted in order to extend the storage life of a liquid whole egg-skim milk (LWE-SM) mixed beverage to enhance its safety and the safety of related beverages. Bacillus cereus vegetative cells (1 x 10(8) colony-forming units [CFU]/mL) were inoculated in LWE-SM beverages with or without natural antimicrobial supplements: flavonol rich-cocoa powder (cocoanOX 12%, CCX) (700 ppm), vanillin (700 ppm), anise (700 ppm), and cinnamon (700 ppm). B. cereus cells were maintained at 10 degrees C for 10 days in the different beverages to test the bacteriostatic or inhibitory effect of the aforementioned ingredients. Beverages were treated with high hydrostatic pressure (HHP) technology and stored at 10 degrees C for 15 days after treatment. All natural antimicrobials reduced the micro(max) values and increased the lag phase time of B. cereus, and Gompertz growth curves showed different inhibitory effects depending on the substance. The maximum inhibitory effect (1.330 log cycle reduction) was achieved in LWE-SM-cinnamon-supplemented beverage. The maximum inactivation achieved by HHP in LWE-SM beverage was a reduction of around 3.89 +/- 0.25 log cycles at 300 MPa for 12 minutes. When supplemented beverages were treated under the same conditions, enhanced inactivation levels were achieved. This increased inactivation can be attributed to a synergistic effect when the LWE-SM was supplemented with flavonol-rich cocoa powder, cinnamon, and vanillin. The maximum synergistic effect was observed in LWE-SM-CCX-supplemented beverage. During the refrigerated storage of B. cereus HHP-treated cells in beverages to which antimicrobials had been added, the inhibitory effect was dependent on the previously applied pressure level.

A major event of Antarctic ozone hole influence in southern Brazil in October 2016: an analysis of tropospheric and stratospheric dynamics

NASA Astrophysics Data System (ADS)

Dornelles Bittencourt, Gabriela; Bresciani, Caroline; Kirsch Pinheiro, Damaris; Valentin Bageston, José; Schuch, Nelson Jorge; Bencherif, Hassan; Paes Leme, Neusa; Vaz Peres, Lucas

2018-03-01

The Antarctic ozone hole is a cyclical phenomenon that occurs during the austral spring where there is a large decrease in ozone content in the Antarctic region. Ozone-poor air mass can be released and leave through the Antarctic ozone hole, thus reaching midlatitude regions. This phenomenon is known as the secondary effect of the Antarctic ozone hole. The objective of this study is to show how tropospheric and stratospheric dynamics behaved during the occurrence of this event. The ozone-poor air mass began to operate in the region on 20 October 2016. A reduction of ozone content of approximately 23 % was observed in relation to the climatology average recorded between 1992 and 2016. The same air mass persisted over the region and a drop of 19.8 % ozone content was observed on 21 October. Evidence of the 2016 event occurred through daily mean measurements of the total ozone column made with a surface instrument (Brewer MkIII no. 167 Spectrophotometer) located at the Southern Space Observatory (29.42° S, 53.87° W) in São Martinho da Serra, Rio Grande do Sul. Tropospheric dynamic analysis showed a post-frontal high pressure system on 20 and 21 October 2016, with pressure levels at sea level and thickness between 1000 and 500 hPa. Horizontal wind cuts at 250 hPa and omega values at 500 hPa revealed the presence of subtropical jet streams. When these streams were allied with positive omega values at 500 hPa and a high pressure system in southern Brazil and Uruguay, the advance of the ozone-poor air mass that caused intense reductions in total ozone content could be explained.

The J-shaped Curve for Blood Pressure and Cardiovascular Disease Risk: Historical Context and Recent Updates.

PubMed

Rahman, Faisal; McEvoy, John W

2017-08-01

The definition and treatment of hypertension have both changed dramatically over the last century, with recent trials suggesting benefit for lower blood pressure (BP) targets than ever before considered. However, tempering the enthusiasm for more intensive BP targets are long-held concerns that BP reduction below a certain threshold may pose dangers, the so-called "J-curve." In this review, we summarize the evidence for a J-curve in the treatment of hypertension. The Systolic Blood Pressure Intervention Trial (SPRINT) reported that achieving a systolic BP target of 120 mmHg reduces cardiovascular disease in high-risk individuals, supporting more intensive BP reduction. However, contemporary observational studies consistently demonstrate a BP J-curve, the threshold of which is often close to the SPRINT target. Studies also suggest that the BP level of this J-curve may vary based on patient characteristics, including age and comorbidities. There is also more compelling evidence for the specific presence of a J-curve between diastolic BP and coronary events, in contrast to conflicting evidence of a J-curve with systolic BP and cardiovascular disease more generally. There is increased risk of coronary events below a diastolic BP of 60-70 mmHg. In comparison, the presence of a systolic J-curve is less clear and some persons at high risk may actually benefit from systolic levels down to 120 mmHg. Therefore, we suggest a personalized approach to BP management considering individual risks, benefits, and preferences when choosing therapeutic targets. Further, well-designed studies are required to support our suggestions and to define J-curve thresholds more clearly.

Monitoring transient changes within overpressured regions of subduction zones using ambient seismic noise.

PubMed

Chaves, Esteban J; Schwartz, Susan Y

2016-01-01

In subduction zones, elevated pore fluid pressure, generally linked to metamorphic dehydration reactions, has a profound influence on the mechanical behavior of the plate interface and forearc crust through its control on effective stress. We use seismic noise-based monitoring to characterize seismic velocity variations following the 2012 Nicoya Peninsula, Costa Rica earthquake [M w (moment magnitude) 7.6] that we attribute to the presence of pressurized pore fluids. Our study reveals a strong velocity reduction (~0.6%) in a region where previous work identified high forearc pore fluid pressure. The depth of this velocity reduction is constrained to be below 5 km and therefore not the result of near-surface damage due to strong ground motions; rather, we posit that it is caused by fracturing of the fluid-pressurized weakened crust due to dynamic stresses. Although pressurized fluids have been implicated in causing coseismic velocity reductions beneath the Japanese volcanic arc, this is the first report of a similar phenomenon in a subduction zone setting. It demonstrates the potential to identify pressurized fluids in subduction zones using temporal variations of seismic velocity inferred from ambient seismic noise correlations.

Effects of reducing blood pressure on cardiovascular outcomes and mortality in patients with type 2 diabetes: Focus on SGLT2 inhibitors and EMPA-REG OUTCOME.

PubMed

Scheen, André J

2016-11-01

Empagliflozin, a sodium-glucose cotransporter type 2 (SGLT2) inhibitor, has shown a remarkable reduction in cardiovascular and all-cause mortality in patients with type 2 diabetes (T2D) and antecedents of cardiovascular disease in the EMPA-REG OUTCOME trial. This effect has been attributed to a hemodynamic rather than a metabolic effect, partly due to the osmotic/diuretic effect of empagliflozin and to the reduction in arterial blood pressure. The present review will: (1) summarize the results of specific studies having tested the blood pressure lowering effects of SGLT2 inhibitors; (2) describe the results of meta-analyses of trials having evaluated the effects on mortality and cardiovascular outcomes of lowering blood pressure in patients with T2D, with a special focus on baseline and target blood pressures; (3) compare the cardiovascular outcome results in EMPA-REG OUTCOME versus other major trials with antihypertensive agents in patients with T2D; and (4) evaluate post-hoc analyses from EMPA-REG OUTCOME, especially subgroups of patients of special interest regarding the blood pressure lowering hypothesis. Although BP reduction associated to empagliflozin therapy may partly contribute to the benefits reported in EMPA-REG OUTCOME, other mechanisms most probably play a greater role in the overall CV protection and reduction in mortality observed in this trial. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Epidural blood patch for refractory low CSF pressure headache: a pilot study.

PubMed

Madsen, Søren Aalbæk; Fomsgaard, Jonna Storm; Jensen, Rigmor

2011-08-01

Once believed an exceedingly rare disorder, recent evidence suggests that low cerebrospinal fluid (CSF) pressure headache has to be considered an important cause of new daily persistent headaches, particularly among young and middle-aged individuals. Treatment of low CSF pressure headache consists of non-invasive/conservative measures and invasive measures with epidural blood patch providing the cornerstone of the invasive measures. In the present pilot study we therefore aimed to evaluate the treatment efficacy of epidural blood patch (EBP) in treatment-refractory low-pressure headache. Our primary effect parameter was total headache burden defined as area under the curve (AUC: intensity × duration) and as secondary effect parameters we identified: intensity (VAS 0-10), frequency (days per month), duration in hours (total hours/month) and also medication days (days on medication/month). In our primary effect parameter we found a significant reduction in AUC with more than 25% and this is considered to be clinically relevant. We found also a significant and relevant reduction at -22% in intensity. A trend towards reduction in duration was seen. We found no statistically significant reduction in frequency. An increase in days with use of medication was found. Increased awareness of low CSF pressure headache is emphasized and a controlled larger randomized study is needed to confirm the results. However the present results, allows us to conclude that EBP in treatment-refractory low CSF pressure headache can be considered as a treatment option.

OPERATION DOMINIC, SHOT SWORD FISH. Project Officer’s Report. Project 1. 1. Underwater Pressures

DTIC Science & Technology

1985-09-01

LEVEL ACCESSION FOR NT1S GRAfcl DTK TAB UNANNOUNCED JUSTIFICATION D D BY DISTRIBUTION / AVAILABILrTY CODES DIST AW AVAIL AND/OR SPECIAL...The batteries ueed to power the recorderi were composed of new nickel-cadnlum cells with the ssse capacity rating as those used during Hardtack...the better cell quality and approximately 35-percent reduction in power requirements. A new battery-charging circuit of Increased convenience and

Influence of Renal Sympathetic Denervation on Cardiac Extracellular Matrix Turnover and Cardiac Fibrosis.

PubMed

Dörr, Oliver; Liebetrau, Christoph; Möllmann, Helge; Gaede, Luise; Troidl, Christian; Morczeck, Kareen; Wiebe, Jens; Hoffmann, Jedrzej; Voss, Sandra; Bauer, Timm; Hamm, Christian; Nef, Holger

2015-10-01

Renal sympathetic denervation (RSD) represents an effective treatment option for patients with resistant arterial hypertension (HT). Extracellular matrix (ECM) turnover and deposition are essential processes in HT-related cardiovascular remodeling, fibrosis, and cardiac hypertrophy and contribute to hypertensive heart disease. The primary aim of the present study was to examine the effect of RSD on increased collagen turnover as reflected by serum levels of amino-terminal pro-peptides (PINP, PIIINP) and a carboxyl-terminal pro-peptide (PICP), specific biomarkers for cardiac ECM turnover and cardiovascular fibrosis. A total of 100 consecutive patients (mean age: 65.9±10.1 years) undergoing RSD were included in this study. A therapeutic response was defined as an office systolic blood pressure (SBP) reduction of >10mm Hg 6 months after RSD. Venous serum samples for measurement of PICP, PINP, and PIIINP were collected prior to and 6 months after RSD. A significant reduction in the office SBP of 24.3 mm Hg (SBP baseline: 166.9±14.3 mm Hg (P < 0.001) was documented 6 months after RSD. At this time point, the serum levels of PICP, PINP, and PIIINP (P < 0.01) were significantly decreased compared to baseline values in patients with an increased collagen turnover, showing significant differences comparing BP responders and nonresponders. In addition to the effective blood pressure reduction in response to RSD, this study demonstrates a positive effect of RSD on biomarkers reflecting cardiovascular ECM turnover and deposition. These results suggest a beneficial effect of RSD on cardiovascular fibrosis, hypertensive heart disease, and end-organ damage in high-risk patients. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sterically controlled mechanochemistry under hydrostatic pressure

DOE PAGES

Yan, Hao; Yang, Fan; Pan, Ding; ...

2018-02-21

Mechanical stimuli can modify the energy landscape of chemical reactions and enable reaction pathways, offering a synthetic strategy that complements conventional chemistry. These mechanochemical mechanisms have been studied extensively in one-dimensional polymers under tensile stress using ring-opening and reorganization, polymer unzipping and disulfide reduction as model reactions. In these systems, the pulling force stretches chemical bonds, initiating the reaction. Additionally, it has been shown that forces orthogonal to the chemical bonds can alter the rate of bond dissociation. Furthermore, these bond activation mechanisms have not been possible under isotropic, compressive stress (that is, hydrostatic pressure). Here we show that mechanochemistrymore » through isotropic compression is possible by molecularly engineering structures that can translate macroscopic isotropic stress into molecular-level anisotropic strain.« less

Renal denervation: unde venis et quo vadis?

PubMed

Nähle, C P; Düsing, R; Schild, H

2015-04-01

Renal denervation is a minimally invasive, catheter-based option for the treatment of refractory hypertension. Indications and contraindications for renal denervation have been defined in an interdisciplinary manner. The efficacy and safety of the procedure were evaluated. Currently, indication for renal denervation is limited to patients with primary hypertension and a systolic blood pressure of ≥ 160 mm Hg (or ≥ 150 mm Hg in diabetes type 2) despite optimal medical therapy with ≥ 3 different antihypertensive drugs. In this specific patient population, an average blood pressure reduction of 32/14 mmHg was observed in non-randomized/-controlled trials after renal denervation. These results were not confirmed in the first randomized controlled trial with a non-significantly superior blood pressure reduction of 14.1 ± 23.9 mm Hg compared to controls (-11.74 ± 25.94 mm Hg, difference -2.39 mm Hg p = 0.26 for superiority with a margin of 5 mm Hg) who underwent a sham procedure. The efficacy and long-term effects of renal denervation need to be re-evaluated in light of the HTN3 study results. To date, renal denervation should not be performed outside of clinical trials. Future trials should also assess if renal denervation can be performed with sufficient safety and efficacy in patients with hypertension-associated diseases. The use of renal denervation as an alternative therapy (e. g. in patients with drug intolerance) can currently not be advocated. The indication for renal denervation should be assessed in an interdisciplinary fashion and according to current guidelines with a special focus on ruling out secondary causes for arterial hypertension. 5 - 10 % of patients with hypertension suffer from refractory hypertension, but only about 1 % of patients meet the criteria for a renal denervation. Renal denervation leads to a significant decrease in office blood pressure; however, the impact on 24-hour blood pressure measurements remains unclear. In the first randomized controlled trial on renal denervation with a control group undergoing a sham procedure, blood pressure reduction failed to reach the anticipated level of superiority over best medical treatment. Periprocedural complications are rare, but long-term safety can currently not be appraised due to the limited data available. © Georg Thieme Verlag KG Stuttgart · New York.

Estimated cardiovascular relative risk reduction from fixed-dose combination pill (polypill) treatment in a wide range of patients with a moderate risk of cardiovascular disease.

PubMed

Lafeber, Melvin; Webster, Ruth; Visseren, Frank Lj; Bots, Michiel L; Grobbee, Diederick E; Spiering, W; Rodgers, Anthony

2016-08-01

Recent data indicate that fixed-dose combination (FDC) pills, polypills, can produce sizeable risk factor reductions. There are very few published data on the consistency of the effects of a polypill in different patient populations. It is unclear for example whether the effects of the polypill are mainly driven by the individuals with high individual risk factor levels. The aim of the present study is to examine whether baseline risk factor levels modify the effect of polypill treatment on low-density lipoprotein (LDL)-cholesterol, blood pressure (BP), calculated cardiovascular relative risk reduction and adverse events. This paper describes a post-hoc analysis of a randomised, placebo-controlled trial of a polypill (containing aspirin 75 mg, simvastatin 20 mg, lisinopril 10 mg and hydrochlorothiazide 12.5 mg) in 378 individuals without an indication for any component of the polypill, but who had an estimated five-year risk for cardiovascular disease ≥7.5%. The outcomes considered were effect modification by baseline risk factor levels on change in LDL-cholesterol, systolic BP, calculated cardiovascular relative risk reduction and adverse events. The mean LDL-cholesterol in the polypill group was 0.9 mmol/l (95% confidence interval (CI): 0.8-1.0) lower compared with the placebo group during follow-up. Those with a baseline LDL-cholesterol >3.6 mmol/l achieved a greater absolute LDL-cholesterol reduction with the polypill compared with placebo, than patients with an LDL-cholesterol ≤3.6 mmol/l (-1.1 versus -0.6 mmol/l, respectively). The mean systolic BP was 10 mm Hg (95% CI: 8-12) lower in the polypill group. In participants with a baseline systolic BP >135 mm Hg the polypill resulted in a greater absolute systolic BP reduction with the polypill compared with placebo, than participants with a systolic BP ≤ 135 mm Hg (-12 versus -7 mm Hg, respectively). Calculated from individual risk factor reductions, the mean cardiovascular relative risk reduction was 48% (95% CI: 43-52) in the polypill group. Both baseline LDL-cholesterol and estimated cardiovascular risk were significant modifiers of the estimated cardiovascular relative risk reduction caused by the polypill. Adverse events did not appear to be related to baseline risk factor levels or the estimated cardiovascular risk. This study demonstrated that the effect of a cardiovascular polypill on risk factor levels is modified by the level of these risk factors. Groups defined by baseline LDL-cholesterol or systolic BP had large differences in risk factor reductions but only moderate differences in estimated cardiovascular relative risk reduction, suggesting also that patients with mildly increased risk factor levels but an overall raised cardiovascular risk benefit from being treated with a polypill. © The European Society of Cardiology 2016.

The effectiveness of age-appropriate pre-operative information session on the anxiety level of school-age children undergoing elective surgery in Jordan.

PubMed

Shaheen, Abeer; Nassar, Omayyah; Khalaf, Inaam; Kridli, Suha Al-Oballi; Jarrah, Samiha; Halasa, Suhaila

2018-06-01

Undergoing surgery is an anxious experience for children. Applying anxiety reduction age-appropriate programs by nurses would be beneficial in reducing anxiety to children. To test the effectiveness of age-appropriate preoperative information session in reducing anxiety levels of school-age children undergoing elective surgery in Jordan. The study used a quasi-experimental design. One hundred and twenty-six children were recruited from an educational hospital in Amman from January to June 2012 and were randomly assigned to intervention and control groups. The anxiety levels of children were assessed using the State Anxiety Scale for children, and children's levels of cooperation after surgery were assessed using Children Emotional Manifestation Scale. The heart rate and blood pressure of children were also measured 1 hour before going to operation room. The study results revealed that children in the intervention group reported lower anxiety levels and more cooperation than children in the control group. Also, they displayed lower heart rate and blood pressure than children in the control group. The application of age-appropriate preoperative intervention for children could be beneficial in decreasing anxiety levels and increasing their cooperation post surgery. © 2018 John Wiley & Sons Australia, Ltd.

[Producing know-how and making recommendations for promoting high blood pressure management in Colombia , 1998-2005].

PubMed

Ortega-Bolaños, Jesús

2008-01-01

Producing know-how and making recommendations concerning the most effective health promotion community interventions for managing high blood pressure in Colombia. A systematic review was made of the Cochrane, Lilacs, Ovid, Proquest and Pubmed databases, the main interest of the study lying within the framework of the most effective community interventions around the world for managing high blood pressure. The following search words were used: systematic review, community intervention, cost effectiveness, health promotion and high blood pressure. Studies published in Spanish, English and Portuguese were reviewed. The research strategies used were derived from defining the most pertinent methodological approach for involving individual, interpersonal and community levels in developing the project. 1,041 articles were obtained from the systematic review of the literature: 246 abstracts, 197 articles about educational interventions for preventing and controlling high blood pressure and 53 articles adopting different approaches regarding informative interventions and communication. Only 11 complete referenced articles from this world of information fulfilled the levels of evidence and evaluation criteria necessary for producing recommendations. The available evidence concerning effective, culturally-suitable programmes and for promoting a reduction in these risk factors is limited. Greater evidence regarding community interventions is required for reducing risk factors directed towards special population groups adapted to the cultural characteristics of the participating population. This must involve determinants of the social and physical context related to social practices, these being developed on a large scale within the daily settings in which the subjects and their families are living.

Aldosterone antagonists: effective add-on therapy for the treatment of resistant hypertension.

PubMed

Gaddam, Krishna K; Pratt-Ubunama, Monique N; Calhoun, David A

2006-05-01

Resistant hypertension is defined as blood pressure that remains above target levels despite treatment with three different antihypertensive agents. Cross-sectional analyses and hypertension outcome studies indicate that it is a common clinical problem, which will undoubtedly become increasingly prevalent with an aging and increasingly overweight population. Secondary causes of hypertension are common in patients with resistant hypertension, particularly hyperaldosteronism, with a prevalence of approximately 15-20%. This, however, is likely to be an underestimation of the role excess aldosterone plays in causing resistance to treatment. In subjects with resistant hypertension, suppressed renin levels are common, exceeding 60% in studies conducted by the authors and from centers elsewhere in the world, suggesting occurrence of excess aldosterone beyond cases of true primary aldosteronism. Recent clinical studies indicate that aldosterone antagonists provide significant additional blood pressure reduction when added to treatment regimens of patients with resistant hypertension independent of aldosterone levels. These agents are generally well tolerated. Hyperkalemia is an uncommon complication of aldosterone antagonists, but it can occur. Therefore, biochemical monitoring is necessary, particularly in high-risk patients.

Reducing the Blood Pressure-Related Burden of Cardiovascular Disease: Impact of Achievable Improvements in Blood Pressure Prevention and Control.

PubMed

Hardy, Shakia T; Loehr, Laura R; Butler, Kenneth R; Chakladar, Sujatro; Chang, Patricia P; Folsom, Aaron R; Heiss, Gerardo; MacLehose, Richard F; Matsushita, Kunihiro; Avery, Christy L

2015-10-27

US blood pressure reduction policies are largely restricted to hypertensive populations and associated benefits are often estimated based on unrealistic interventions. We used multivariable linear regression to estimate incidence rate differences contrasting the impact of 2 pragmatic hypothetical interventions to reduce coronary heart disease, stroke, and heart failure (HF) incidence: (1) a population-wide intervention that reduced systolic blood pressure by 1 mm Hg and (2) targeted interventions that reduced the prevalence of unaware, untreated, or uncontrolled blood pressure above goal (per Eighth Joint National Committee treatment thresholds) by 10%. In the Atherosclerosis Risk in Communities Study (n=15 744; 45 to 64 years at baseline, 1987-1989), incident coronary heart disease and stroke were adjudicated by physician panels. Incident HF was defined as the first hospitalization with discharge diagnosis code of "428." A 10% proportional reduction in unaware, untreated, or uncontrolled blood pressure above goal resulted in ≈4.61, 3.55, and 11.01 fewer HF events per 100,000 person-years in African Americans, and 3.77, 1.63, and 4.44 fewer HF events per 100 000 person-years, respectively, in whites. In contrast, a 1 mm Hg population-wide systolic blood pressure reduction was associated with 20.3 and 13.3 fewer HF events per 100 000 person-years in African Americans and whites, respectively. Estimated event reductions for coronary heart disease and stroke were smaller than for HF, but followed a similar pattern for both population-wide and targeted interventions. Modest population-wide shifts in systolic blood pressure could have a substantial impact on cardiovascular disease incidence and should be developed in parallel with interventions targeting populations with blood pressure above goal. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

The efficacy of isometric resistance training utilizing handgrip exercise for blood pressure management: A randomized trial.

PubMed

Carlson, Debra J; Inder, Jodie; Palanisamy, Suresh K A; McFarlane, James R; Dieberg, Gudrun; Smart, Neil A

2016-12-01

Hypertension is a major risk factor contributing to cardiovascular disease, which is the number one cause of deaths worldwide. Although antihypertensive medications are effective at controlling blood pressure, current first-line treatment for hypertension is nonpharmacological lifestyle modifications. Recent studies indicate that isometric resistance training (IRT) may also be effective for assisting with blood pressure management. The aim of this study was to determine the efficacy of IRT for blood pressure management and the suitability of a low-intensity working control group. Forty hypertensive individuals, aged between 36 and 65 years, conducted IRT for 8 weeks. Participants were randomized into 2 groups, working at an intensity of either 5% or 30% of their maximum voluntary contraction. Participants performed 4 × 2 minute isometric handgrip exercises with their nondominant hand, each separated by a 3-minute rest period, 3 days a week. Blood pressure measurements were conducted at baseline and at the end of the protocol using a Finometer. Eight weeks of isometric resistance training resulted in a 7-mmHg reduction of resting systolic blood pressure (SBP) (136 ± 12 to 129 ± 15; P = 0.04) in the 30% group. Reductions of 4 mmHg were also seen in mean arterial pressure (MAP) (100 ± 8 to 96 ± 11; P = 0.04) in the 30% group. There were no statistically significant reductions in diastolic blood pressure for the 30% group, or any of the data for the 5% group. Isometric resistance training conducted using handgrip exercise at 30% of maximum voluntary contraction significantly reduced SBP and MAP. A lack of reduction in blood pressure in the 5% group indicates that a low-intensity group may be suitable as a working control for future studies.

Effect of aromatherapy massage on anxiety, depression, and physiologic parameters in older patients with the acute coronary syndrome: A randomized clinical trial.

PubMed

Bahrami, Tahereh; Rejeh, Nahid; Heravi-Karimooi, Majideh; Vaismoradi, Mojtaba; Tadrisi, Seyed Davood; Sieloff, Christina

2017-12-01

This study aimed to investigate the effect of aromatherapy massage on anxiety, depression, and physiologic parameters in older patients with acute coronary syndrome. This randomized controlled trial was conducted on 90 older women with acute coronary syndrome. The participants were randomly assigned into the intervention and control groups (n = 45). The intervention group received reflexology with lavender essential oil, but the control group only received routine care. Physiologic parameters, the levels of anxiety and depression in the hospital were evaluated using a checklist and the Hospital's Anxiety and Depression Scale, respectively, before and immediately after the intervention. Significant differences in the levels of anxiety and depression were reported between the groups after the intervention. The analysis of physiological parameters revealed a statistically significant reduction (P < .05) in systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate. However, no significant difference was observed in the respiratory rate. Aromatherapy massage can be considered by clinical nurses an efficient therapy for alleviating psychological and physiological responses among older women suffering from acute coronary syndrome. © 2017 John Wiley & Sons Australia, Ltd.

Reduction of oxidative stress by compression stockings in standing workers.

PubMed

Flore, Roberto; Gerardino, Laura; Santoliquido, Angelo; Catananti, Cesare; Pola, Paolo; Tondi, Paolo

2007-08-01

Healthy workers who stand for prolonged periods show enhanced production of reactive oxygen species (ROS) in their systemic circulation. Oxidative stress is thought to be a risk factor for chronic venous insufficiency and other systemic diseases. To evaluate the effectiveness of compression stockings in the prevention of oxidative stress at work. ROS and venous pressure of the lower limbs were measured in 55 theatre nurses who stood in the operating theatre for >6 h, 23 industrial ironers who stood for up to 5 h during their shift and 65 outpatient department nurses and 35 laundry workers who acted as controls. Subjects and controls were examined on two consecutive days before and after work and with and without compression stockings. Without compression stockings, lower limb venous pressure increased significantly after work in all subjects and controls (P < 0.001), while only operating theatre nurses showed significantly higher mean levels of ROS (P < 0.001). There was no significant difference in venous pressures and ROS levels after work in subjects or controls when wearing compression stockings. Our data suggest a preventive role of compression stockings against oxidative stress in healthy workers with a standing occupation.

Internal performance characteristics of thrust-vectored axisymmetric ejector nozzles

NASA Technical Reports Server (NTRS)

Lamb, Milton

1995-01-01

A series of thrust-vectored axisymmetric ejector nozzles were designed and experimentally tested for internal performance and pumping characteristics at the Langley research center. This study indicated that discontinuities in the performance occurred at low primary nozzle pressure ratios and that these discontinuities were mitigated by decreasing expansion area ratio. The addition of secondary flow increased the performance of the nozzles. The mid-to-high range of secondary flow provided the most overall improvements, and the greatest improvements were seen for the largest ejector area ratio. Thrust vectoring the ejector nozzles caused a reduction in performance and discharge coefficient. With or without secondary flow, the vectored ejector nozzles produced thrust vector angles that were equivalent to or greater than the geometric turning angle. With or without secondary flow, spacing ratio (ejector passage symmetry) had little effect on performance (gross thrust ratio), discharge coefficient, or thrust vector angle. For the unvectored ejectors, a small amount of secondary flow was sufficient to reduce the pressure levels on the shroud to provide cooling, but for the vectored ejector nozzles, a larger amount of secondary air was required to reduce the pressure levels to provide cooling.

Suppression of tonal noise in a centrifugal fan using guide vanes

NASA Astrophysics Data System (ADS)

Paramasivam, Kishokanna; Rajoo, Srithar; Romagnoli, Alessandro

2015-11-01

This paper presents the work aiming for tonal noise reduction in a centrifugal fan. In previous studies, it is well documented that tonal noise is the dominant noise source generated in centrifugal fans. Tonal noise is generated due to the aerodynamic interaction between the rotating impeller and stationary diffuser vanes. The generation of tonal noise is related to the pressure fluctuation at the leading edge of the stationary vane. The tonal noise is periodic in time which occurs at the blade passing frequency (BPF) and its harmonics. Much of previous studies, have shown that the stationary vane causes the tonal noise and generation of non-rotational turbulent noise. However, omitting stationary vanes will lead to the increase of non-rotational turbulent noise resulted from the high velocity of the flow leaving the impeller. Hence in order to reduce the tonal noise and the non-rotational noise, guide vanes were designed as part of this study to replace the diffuser vanes, which were originally used in the chosen centrifugal fan. The leading edge of the guide vane is tapered. This modification reduces the strength of pressure fluctuation resulting from the interaction between the impeller outflow and stationary vane. The sound pressure level at blade passing frequency (BPF) is reduced by 6.8 dB, the 2nd BPF is reduced by 4.1 dB and the 3rd BPF reduced by about 17.5 dB. The overall reduction was 0.9 dB. The centrifugal fan with tapered guide vanes radiates lower tonal noise compared to the existing diffuser vanes. These reductions are achieved without compromising the performance of the centrifugal fan. The behavior of the fluid flow was studied using computational fluid dynamics (CFD) tools and the acoustics characteristics were determined through experiments in an anechoic chamber.

Shock Tunnel Studies of the Hypersonic Flowfield around the Hypervelocity Ballistic Models with Aerospikes

NASA Astrophysics Data System (ADS)

Balakalyani, G.; Saravanan, S.; Jagadeesh, G.

Reduced drag and aerodynamic heating are the two basic design requirements for any hypersonic vehicle [1]. The flowfield around an axisymmetric blunt body is characterized by a bow shockwave standing ahead of its nose. The pressure and temperature behind this shock wave are very high. This increased pressure and temperature are responsible for the high levels of drag and aerodynamic heating over the body. In the past, there have been many investigations on the use of aerospikes as a drag reduction tool. These studies on spiked bodies aim at reducing both the drag and aerodynamic heating by modifying the hypersonic flowfield ahead of the nose of the body [2]. However, most of them used very simple configurations to experimentally study the drag reduction using spikes at hypersonic speeds [3] and therefore very little experimental data is available for a realistic geometric configuration. In the present study, the standard AGARD Hypervelocity Ballistic model 1 is used as the test model. The addition of the spike to the blunt body significantly alters the flowfield ahead of the nose, leading to the formation of a low pressure conical recirculation region, thus causing a reduction in drag and wall heat flux [4]. In the present investigation, aerodynamic drag force is measured over the Hypervelocity Ballistic model-1, with and without spike, at a flow enthalpy of 1.7 MJ/kg. The experiments are carried out at a Mach number of 8 and at zero angle of attack. An internally mountable accelerometer based 3-component force balance system is used to measure the aerodynamic forces on the model. Also computational studies are carried out to complement the experiments.

Quantifying voids effecting delamination in carbon/epoxy composites: static and fatigue fracture behavior

NASA Astrophysics Data System (ADS)

Hakim, I.; May, D.; Abo Ras, M.; Meyendorf, N.; Donaldson, S.

2016-04-01

On the present work, samples of carbon fiber/epoxy composites with different void levels were fabricated using hand layup vacuum bagging process by varying the pressure. Thermal nondestructive methods: thermal conductivity measurement, pulse thermography, pulse phase thermography and lock-in-thermography, and mechanical testing: modes I and II interlaminar fracture toughness were conducted. Comparing the parameters resulted from the thermal nondestructive testing revealed that voids lead to reductions in thermal properties in all directions of composites. The results of mode I and mode II interlaminar fracture toughness showed that voids lead to reductions in interlaminar fracture toughness. The parameters resulted from thermal nondestructive testing were correlated to the results of mode I and mode II interlaminar fracture toughness and voids were quantified.

Gas dynamic improvement of the axial compressor design for reduction of the flow non-uniformity level

NASA Astrophysics Data System (ADS)

Matveev, V. N.; Baturin, O. V.; Kolmakova, D. A.; Popov, G. M.

2017-01-01

Circumferential nonuniformity of gas flow is one of the main problems in the gas turbine engine. Usually, the flow circumferential nonuniformity appears near the annular frame located in the flow passage of the engine. The presence of circumferential nonuniformity leads to the increased dynamic stresses in the blade rows and the blade damage. The goal of this research was to find the ways of the flow non-uniformity reduction, which would not require a fundamental changing of the engine design. A new method for reducing the circumferential nonuniformity of the gas flow was proposed that allows the prediction of the pressure peak values of the rotor blades without computationally expensive CFD calculations.

Evaluation of Millstone-2 steam generator chemical decontamination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, D.T.; Blok, J.

The steam generator channel heads at Millstone-2 were decontaminated prior to carrying out extensive maintenance work in 1983. Isotopic gamma ray measurements were made of the inner channel head surfaces before and after the decontamination to evaluate the effectiveness of the process. The Combustion Engineering/Kraftwerk Union chemical decontamination, by itself, provided a decontamination factor ranging from 2.7 to 6.6 for the various steam generator surfaces. The corresponding average dose rate reduction factor, based on gross-gamma radiation surveys, was approximately 1.5 to 2.5. Following the chemical treatment, high pressure water flushing reduced the radiation levels still further, to an average overallmore » dose reduction factor of 5.3 to 7.2.« less

[Human venous hemodynamics in microgravity and prediction of orthostatic tolerance in flight].

PubMed

Kotovskaya, A R; Fomina, G A

2013-01-01

The paper presents the results of investigating the lower limbs venous status in cosmonauts (n = 13) with the use of occlusion plethysmography in 6-month missions to the Russian segment of the International space station (ISS). An interrelation of shifts in venous capacitance, compliance and filling with orthostatic tolerance (OT) in the lower body negative pressure test (LBNP) was stated. OT predictability by the leg vein status in the course of space flight was demonstrated. The objective changes of veins predictive of OT reduction were identified. There are 3 levels of changes in venous capacitance, compliance and filling that prognosticate respective reductions in LBNP tolerance and were attested in 91% of the in-flight LBNP testing.

The effect of music on biochemical markers and self-perceived stress among first-line nurses: a randomized controlled crossover trial.

PubMed

Lai, Hui-Ling; Li, Yin-Ming

2011-11-01

The aim of this study was to examine the effects of music on stress indices and to examine the association between music preference and stress. Although clinical studies have demonstrated the effectiveness of music on stress, study results have been inconsistent. At the time of writing, no known publications had investigated the effects of preferred music on workers in high-stress professions such as nursing. Using a randomized crossover controlled trial, 54 nurses were randomly assigned to a music/chair rest sequence or chair rest/music sequence during the period February to June 2006. Each intervention lasted for 30 minutes. Participants in the music condition listened to self-selected soothing music using headphones for 30 minutes. In the chair rest condition, participants sat quietly for 30 minutes. Serial measurements of participants' heart rate, mean arterial pressure, finger temperature and cortisol levels were taken with a BP monitor and chemillumincent immunoassay every 15 minutes throughout the procedure. Compared with chair rest, participants had a lower perceived stress level, cortisol, heart rate, mean arterial pressure and higher finger temperature while listening to music (P < 0·05). Significant differences were also found between the two conditions in terms of post-test heart rate, cortisol levels, finger temperature and mean arterial pressure (P < 0·05). Music preference scores ranged between 7 and 10, with a mean score of 8·81 (sd = 1·05), and was significantly associated with mean arterial pressure, cortisol levels, self-perceived stress and finger temperature. The findings provided evidence for nurses to use soothing music as a research-based nursing intervention for stress reduction. © 2011 The Authors. Journal of Advanced Nursing © 2011 Blackwell Publishing Ltd.

Hydrostatic Pressure Regulates MicroRNA Expression Levels in Osteoarthritic Chondrocyte Cultures via the Wnt/β-Catenin Pathway.

PubMed

Cheleschi, Sara; De Palma, Anna; Pecorelli, Alessandra; Pascarelli, Nicola Antonio; Valacchi, Giuseppe; Belmonte, Giuseppe; Carta, Serafino; Galeazzi, Mauro; Fioravanti, Antonella

2017-01-12

Mechanical loading and hydrostatic pressure (HP) regulate chondrocytes' metabolism; however, how mechanical stimulation acts remain unclear. MicroRNAs (miRNAs) play an important role in cartilage homeostasis, mechanotransduction, and in the pathogenesis of osteoarthritis (OA). This study investigated the effects of a cyclic HP (1-5 MPa), in both normal and OA human chondrocytes, on the expression of miR-27a/b , miR-140 , miR-146a/b , and miR-365 , and of their target genes ( MMP-13 , ADAMTS-5 , IGFBP-5 , and HDAC-4 ). Furthermore, we assessed the possible involvement of Wnt/β-catenin pathway in response to HP. Chondrocytes were exposed to HP for 3h and the evaluations were performed immediately after pressurization, and following 12, 24, and 48 h. Total RNA was extracted and used for real-time PCR. β-catenin was detected by Western blotting analysis and immunofluorescence. In OA chondrocytes, HP induced a significant increase ( p < 0.01) of the expression levels of miR-27a/b , miR-140 , and miR-146a , and a significant reduction ( p < 0.01) of miR-365 at all analyzed time points. MMP-13 , ADAMTS-5 , and HDAC-4 were significantly downregulated following HP, while no significant modification was found for IGFBP-5 . β-catenin levels were significantly increased ( p < 0.001) in OA chondrocytes at basal conditions and significantly reduced ( p < 0.01) by HP. Pressurization did not cause any significant modification in normal cells. In conclusion, in OA chondrocytes, HP restores the expression levels of some miRNAs, downregulates MMP-13, ADAMTS-5, and HDAC-4, and modulates the Wnt/β-catenin pathway activation.

Hydrostatic Pressure Regulates MicroRNA Expression Levels in Osteoarthritic Chondrocyte Cultures via the Wnt/β-Catenin Pathway

PubMed Central

Cheleschi, Sara; De Palma, Anna; Pecorelli, Alessandra; Pascarelli, Nicola Antonio; Valacchi, Giuseppe; Belmonte, Giuseppe; Carta, Serafino; Galeazzi, Mauro; Fioravanti, Antonella

2017-01-01

Mechanical loading and hydrostatic pressure (HP) regulate chondrocytes’ metabolism; however, how mechanical stimulation acts remain unclear. MicroRNAs (miRNAs) play an important role in cartilage homeostasis, mechanotransduction, and in the pathogenesis of osteoarthritis (OA). This study investigated the effects of a cyclic HP (1–5 MPa), in both normal and OA human chondrocytes, on the expression of miR-27a/b, miR-140, miR-146a/b, and miR-365, and of their target genes (MMP-13, ADAMTS-5, IGFBP-5, and HDAC-4). Furthermore, we assessed the possible involvement of Wnt/β-catenin pathway in response to HP. Chondrocytes were exposed to HP for 3h and the evaluations were performed immediately after pressurization, and following 12, 24, and 48 h. Total RNA was extracted and used for real-time PCR. β-catenin was detected by Western blotting analysis and immunofluorescence. In OA chondrocytes, HP induced a significant increase (p < 0.01) of the expression levels of miR-27a/b, miR-140, and miR-146a, and a significant reduction (p < 0.01) of miR-365 at all analyzed time points. MMP-13, ADAMTS-5, and HDAC-4 were significantly downregulated following HP, while no significant modification was found for IGFBP-5. β-catenin levels were significantly increased (p < 0.001) in OA chondrocytes at basal conditions and significantly reduced (p < 0.01) by HP. Pressurization did not cause any significant modification in normal cells. In conclusion, in OA chondrocytes, HP restores the expression levels of some miRNAs, downregulates MMP-13, ADAMTS-5, and HDAC-4, and modulates the Wnt/β-catenin pathway activation. PMID:28085114

Understanding the Effect of Biomineralization on Subsurface Injection Processes

NASA Astrophysics Data System (ADS)

Zamani, A.; Montoya, B.; Gabr, M.

2017-12-01

Microbial induced calcium carbonate precipitation (MICP) is a natural soil improvement technique. The calcium carbonate cementation increases the soil's shear strength, stiffness, and dilative tendencies; however, it may also reduce the permeability of the soil due to the reduction in pore space. Reduction in permeability can lead to an increase in treatment injection pressures or decrease in injection distance. Therefore, an investigation of the extent of permeability reduction is necessary to understand the effect on in situ injection procedures. A suite of soil column experiments were conducted on clean loose silica sand and loose silty sand (i.e., 15% non-plastic silt) by inducing MICP to incrementally higher levels of biomineralization (e.g., from an untreated state to a moderately cemented state for each soil type). The level of biomineralization was assessed using shear wave velocity measurements. Once the target levels of shear wave velocity were reached, the MICP treatments were terminated, and constant head permeability tests were conducted. The experimental results provided a relationship between permeability reduction and level of biomineralization. Upon completion of the permeability tests, the calcium carbonate minerals were evaluated with scanning electron microscopy and the distribution of cementation along the soil column height was assessed using gravimetric acid washing. The changes in permeability are upscaled towards in situ treatment by evaluating the resulting changes in allowable injection rate and radius of influence due to the MICP implementation by numerically modeling the groundwater flow using the finite element programs Seep/W and Sigma/W. The numerical results indicate the allowable injection rate and radius of influence are affected by both the reduction in permeability and the increase in stiffness from the MICP process. The injection simulations with clean sand indicate the reduction of permeability is overshadowed by the increase in stiffness of the material, and the allowable injection rate can increase as biomineralization occurs. However, the injection simulations with silty sand indicate the increase in stiffness compensates for the reduction in permeability, and allowable injection rate remains constant during the treatment.

Dietary Flavanols: A Review of Select Effects on Vascular Function, Blood Pressure, and Exercise Performance.

PubMed

Al-Dashti, Yousef A; Holt, Roberta R; Stebbins, Charles L; Keen, Carl L; Hackman, Robert M

2018-05-02

An individual's diet affects numerous physiological functions and can play an important role in reducing the risk of cardiovascular disease. Epidemiological and clinical studies suggest that dietary flavanols can be an important modulator of vascular risk. Diets and plant extracts rich in flavanols have been reported to lower blood pressure, especially in prehypertensive and hypertensive individuals. Flavanols may act in part through signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxing and constricting factors. During exercise, flavanols have been reported to modulate metabolism and respiration (e.g., maximal oxygen uptake, O 2 cost of exercise, and energy expenditure), and reduce oxidative stress and inflammation, resulting in increased skeletal muscle efficiency and endurance capacity. Flavanol-induced reductions in blood pressure during exercise may decrease the work of the heart. Collectively, these effects suggest that flavanols can act as an ergogenic aid to help delay the onset of fatigue. More research is needed to better clarify the effects of flavanols on vascular function, blood pressure regulation, and exercise performance and establish safe and effective levels of intake. Flavanol-rich foods and food products can be useful components of a healthy diet and lifestyle program for those seeking to better control their blood pressure or to enhance their physical activity. Key teaching points • Epidemiological and clinical studies indicate that dietary flavanols can reduce the risk of vascular disease. • Diets and plant extracts rich in flavanols have been reported to lower blood pressure and improve exercise performance in humans. • Mechanisms by which flavanols may reduce blood pressure function include alterations in signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxation and constriction factors. • Mechanisms by which flavanols may enhance exercise performance include modulation of metabolism and respiration (e.g., maximal oxygen uptake, O 2 cost of exercise, and energy expenditure) and reduction of oxidative stress and inflammation. These effects can result in increased skeletal muscle efficiency and endurance capacity. • Further research is needed to clarify the amount, timing, and frequency of flavanol intake for blood pressure regulation and exercise performance.

Optimal Flow Control Design

NASA Technical Reports Server (NTRS)

Allan, Brian; Owens, Lewis

2010-01-01

In support of the Blended-Wing-Body aircraft concept, a new flow control hybrid vane/jet design has been developed for use in a boundary-layer-ingesting (BLI) offset inlet in transonic flows. This inlet flow control is designed to minimize the engine fan-face distortion levels and the first five Fourier harmonic half amplitudes while maximizing the inlet pressure recovery. This concept represents a potentially enabling technology for quieter and more environmentally friendly transport aircraft. An optimum vane design was found by minimizing the engine fan-face distortion, DC60, and the first five Fourier harmonic half amplitudes, while maximizing the total pressure recovery. The optimal vane design was then used in a BLI inlet wind tunnel experiment at NASA Langley's 0.3-meter transonic cryogenic tunnel. The experimental results demonstrated an 80-percent decrease in DPCPavg, the reduction in the circumferential distortion levels, at an inlet mass flow rate corresponding to the middle of the operational range at the cruise condition. Even though the vanes were designed at a single inlet mass flow rate, they performed very well over the entire inlet mass flow range tested in the wind tunnel experiment with the addition of a small amount of jet flow control. While the circumferential distortion was decreased, the radial distortion on the outer rings at the aerodynamic interface plane (AIP) increased. This was a result of the large boundary layer being distributed from the bottom of the AIP in the baseline case to the outer edges of the AIP when using the vortex generator (VG) vane flow control. Experimental results, as already mentioned, showed an 80-percent reduction of DPCPavg, the circumferential distortion level at the engine fan-face. The hybrid approach leverages strengths of vane and jet flow control devices, increasing inlet performance over a broader operational range with significant reduction in mass flow requirements. Minimal distortion level requirements are met using vanes alone, avoiding engine stall and increasing robustness of this hybrid inlet flow control approach. This design applies to aerospace applications needing flush-mounted boundary-layer-ingesting inlets.

Association of Intensive Blood Pressure Control and Kidney Disease Progression in Nondiabetic Patients With Chronic Kidney Disease: A Systematic Review and Meta-analysis.

PubMed

Tsai, Wan-Chuan; Wu, Hon-Yen; Peng, Yu-Sen; Yang, Ju-Yeh; Chen, Hung-Yuan; Chiu, Yen-Ling; Hsu, Shih-Ping; Ko, Mei-Ju; Pai, Mei-Fen; Tu, Yu-Kang; Hung, Kuan-Yu; Chien, Kuo-Liong

2017-06-01

The optimal blood pressure (BP) target remains debated in nondiabetic patients with chronic kidney disease (CKD). To compare intensive BP control (<130/80 mm Hg) with standard BP control (<140/90 mm Hg) on major renal outcomes in patients with CKD without diabetes. Searches of PubMed, MEDLINE, Embase, and Cochrane Library for publications up to March 24, 2016. Randomized clinical trials that compared an intensive vs a standard BP target in nondiabetic adults with CKD, reporting changes in glomerular filtration rate (GFR), doubling of serum creatinine level, 50% reduction in GFR, end-stage renal disease (ESRD), or all-cause mortality. Random-effects meta-analyses for pooling effect measures. Meta-regression and subgroup analyses for exploring heterogeneity. Differences in annual rate of change in GFR were expressed as mean differences with 95% CIs. Differences in doubling of serum creatinine or 50% reduction in GFR, ESRD, composite renal outcome, and all-cause mortality were expressed as risk ratios (RRs) with 95% CIs. We identified 9 trials with 8127 patients and a median follow-up of 3.3 years. Compared with standard BP control, intensive BP control did not show a significant difference on the annual rate of change in GFR (mean difference, 0.07; 95% CI, -0.16 to 0.29 mL/min/1.73 m2/y), doubling of serum creatinine level or 50% reduction in GFR (RR, 0.99; 95% CI, 0.76-1.29), ESRD (RR, 0.96; 95% CI, 0.78-1.18), composite renal outcome (RR, 0.99; 95% CI, 0.81-1.21), or all-cause mortality (RR, 0.95; 95% CI, 0.66-1.37). Nonblacks and patients with higher levels of proteinuria showed a trend of lower risk of kidney disease progression with intensive BP control. Targeting BP below the current standard did not provide additional benefit for renal outcomes compared with standard treatment during a follow-up of 3.3 years in patients with CKD without diabetes. However, nonblack patients or those with higher levels of proteinuria might benefit from the intensive BP-lowering treatments.

Underwater sound from vessel traffic reduces the effective communication range in Atlantic cod and haddock.

PubMed

Stanley, Jenni A; Van Parijs, Sofie M; Hatch, Leila T

2017-11-07

Stellwagen Bank National Marine Sanctuary is located in Massachusetts Bay off the densely populated northeast coast of the United States; subsequently, the marine inhabitants of the area are exposed to elevated levels of anthropogenic underwater sound, particularly due to commercial shipping. The current study investigated the alteration of estimated effective communication spaces at three spawning locations for populations of the commercially and ecologically important fishes, Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Both the ambient sound pressure levels and the estimated effective vocalization radii, estimated through spherical spreading models, fluctuated dramatically during the three-month recording periods. Increases in sound pressure level appeared to be largely driven by large vessel activity, and accordingly exhibited a significant positive correlation with the number of Automatic Identification System tracked vessels at the two of the three sites. The near constant high levels of low frequency sound and consequential reduction in the communication space observed at these recording sites during times of high vocalization activity raises significant concerns that communication between conspecifics may be compromised during critical biological periods. This study takes the first steps in evaluating these animals' communication spaces and alteration of these spaces due to anthropogenic underwater sound.

The benefit of HH during the CPAP titration in the cool sleeping environment.

PubMed

Li, Yayong; Wang, Yina

2016-12-01

Upper airway symptom associated with continuous positive airway pressure (CPAP) treatment is an important factor influencing CPAP adherence. There are conflicting data on the effect of a heated humidifier (HH) during CPAP titration for patients with obstructive sleep apnea hypopnea syndrome (OSAHS). This study investigated the effects of HH during CPAP titration in the cool sleeping environment. Forty newly diagnosed OSAHS patients who received CPAP titration in the cool sleeping environment were randomly assigned to HH and non-HH groups. A questionnaire was used to evaluate upper airway symptoms, satisfaction with initial CPAP treatment, and willingness to further use CPAP. Some therapy parameters including leak, apnea hypopnea index (AHI) reduction, and optimal CPAP pressure level were analyzed. We compared these subjective and objective data between the two groups. In subjective sensation, the use of HH can alleviate upper airway symptoms associated with CPAP titration (P < 0.001). The HH group has benefit in satisfaction with initial CPAP treatment (P < 0.001) and further willingness to use CPAP (P < 0.01), although there were no significant differences in leak, AHI reduction, and optimal CPAP pressure between the two groups. The use of HH is recommended during CPAP titration in the cool sleeping environment because of its benefit in the treatment of upper airway symptoms associated with CPAP therapy and improvement of the CPAP acceptance.

Simulation on a car interior aerodynamic noise control based on statistical energy analysis

NASA Astrophysics Data System (ADS)

Chen, Xin; Wang, Dengfeng; Ma, Zhengdong

2012-09-01

How to simulate interior aerodynamic noise accurately is an important question of a car interior noise reduction. The unsteady aerodynamic pressure on body surfaces is proved to be the key effect factor of car interior aerodynamic noise control in high frequency on high speed. In this paper, a detail statistical energy analysis (SEA) model is built. And the vibra-acoustic power inputs are loaded on the model for the valid result of car interior noise analysis. The model is the solid foundation for further optimization on car interior noise control. After the most sensitive subsystems for the power contribution to car interior noise are pointed by SEA comprehensive analysis, the sound pressure level of car interior aerodynamic noise can be reduced by improving their sound and damping characteristics. The further vehicle testing results show that it is available to improve the interior acoustic performance by using detailed SEA model, which comprised by more than 80 subsystems, with the unsteady aerodynamic pressure calculation on body surfaces and the materials improvement of sound/damping properties. It is able to acquire more than 2 dB reduction on the central frequency in the spectrum over 800 Hz. The proposed optimization method can be looked as a reference of car interior aerodynamic noise control by the detail SEA model integrated unsteady computational fluid dynamics (CFD) and sensitivity analysis of acoustic contribution.