Changes in ambient temperature elicit divergent control of metabolic and cardiovascular actions by leptin.

PubMed

do Carmo, Jussara M; da Silva, Alexandre A; Romero, Damian G; Hall, John E

2017-06-01

Interactions of hypothalamic signaling pathways that control body temperature (BT), blood pressure (BP), and energy balance are poorly understood. We investigated whether the chronic BP and metabolic actions of leptin are differentially modulated by changes in ambient temperature ( T A ). Mean arterial pressure (MAP), heart rate (HR), BT, motor activity (MA), and oxygen consumption ( V o 2 ) were measured 24 h/d at normal laboratory T A (23°C), at thermoneutral zone (TNZ, 30°C) for mice or during cold exposure (15°C) in male wild-type mice. After control measurements, leptin (4 μg/kg/min) or saline vehicle was infused for 7 d. At TNZ, leptin reduced food intake (-11.0 ± 0.5 g cumulative deficit) and body weight by 6% but caused no changes in MAP or HR. At 15°C, leptin infusion did not alter food intake but increased MAP and HR (8 ± 1 mmHg and 33 ± 7 bpm), while V o 2 increased by ∼10%. Leptin reduced plasma glucose and insulin levels at 15°C but not at 30°C. These results demonstrate that the chronic anorexic effects of leptin are enhanced at TNZ, while its effects on insulin and glucose levels are attenuated and its effects on BP and HR are abolished. Conversely, cold T A caused resistance to leptin's anorexic effects but amplified its effects to raise BP and reduce insulin and glucose levels. Thus, the brain circuits by which leptin regulates food intake and cardiovascular function are differentially influenced by changes in T A -Do Carmo, J. M., da Silva, A. A., Romero, D. G., Hall, J. E. Changes in ambient temperature elicit divergent control of metabolic and cardiovascular actions by leptin. © FASEB.

Evaluation of Plastic Media Blasting Equipment

DTIC Science & Technology

1987-04-01

the differential pressure across the filter element or by a timer with a differential pressure switch override. The timer and the differential pressure ...automatic. The mechanism should be activated by the differential pressure across the filter element or by a timer with a differential pressure switch override...The timer and the differential pressure switch settings should be adjustable. The dust then falls to the bottom of the baghouse for

Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor

PubMed Central

Ojeda, Norma B.; Royals, Thomas P.

2013-01-01

This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg−1·min−1) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg−1·min−1) significantly attenuated these hemodynamic changes (P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats. PMID:23344570

Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor.

PubMed

Ojeda, Norma B; Royals, Thomas P; Alexander, Barbara T

2013-04-01

This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg(-1)·min(-1)) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg(-1)·min(-1)) significantly attenuated these hemodynamic changes (P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats.

Visualization and quantification of capillary drainage in the pore space of laminated sandstone by a porous plate method using differential imaging X-ray microtomography

NASA Astrophysics Data System (ADS)

Lin, Qingyang; Bijeljic, Branko; Rieke, Holger; Blunt, Martin J.

2017-08-01

The experimental determination of capillary pressure drainage curves at the pore scale is of vital importance for the mapping of reservoir fluid distribution. To fully characterize capillary drainage in a complex pore space, we design a differential imaging-based porous plate (DIPP) method using X-ray microtomography. For an exemplar mm-scale laminated sandstone microcore with a porous plate, we quantify the displacement from resolvable macropores and subresolution micropores. Nitrogen (N2) was injected as the nonwetting phase at a constant pressure while the porous plate prevented its escape. The measured porosity and capillary pressure at the imaged saturations agree well with helium measurements and experiments on larger core samples, while providing a pore-scale explanation of the fluid distribution. We observed that the majority of the brine was displaced by N2 in macropores at low capillary pressures, followed by a further brine displacement in micropores when capillary pressure increases. Furthermore, we were able to discern that brine predominantly remained within the subresolution micropores, such as regions of fine lamination. The capillary pressure curve for pressures ranging from 0 to 1151 kPa is provided from the image analysis compares well with the conventional porous plate method for a cm-scale core but was conducted over a period of 10 days rather than up to few months with the conventional porous plate method. Overall, we demonstrate the capability of our method to provide quantitative information on two-phase saturation in heterogeneous core samples for a wide range of capillary pressures even at scales smaller than the micro-CT resolution.

Cardiovascular and Metabolic Consequences of Testosterone Supplements in Young and Old Male Spontaneously Hypertensive Rats: Implications for Testosterone Supplements in Men.

PubMed

Dalmasso, Carolina; Patil, Chetan N; Yanes Cardozo, Licy L; Romero, Damian G; Maranon, Rodrigo O

2017-10-17

The safety of testosterone supplements in men remains unclear. In the present study, we tested the hypothesis that in young and old male spontaneously hypertensive rats (SHR), long-term testosterone supplements increase blood pressure and that the mechanism is mediated in part by activation of the renin-angiotensin system. In untreated males, serum testosterone exhibited a sustained decrease after 5 months of age, reaching a nadir by 18 to 22 months of age. The reductions in serum testosterone were accompanied by an increase in body weight until very old age (18 months). Testosterone supplements were given for 6 weeks to young (12 weeks-YMSHR) and old (21-22 months-OMSHR) male SHR that increased serum testosterone by 2-fold in young males and by 4-fold in old males. Testosterone supplements decreased body weight, fat mass, lean mass, and plasma leptin, and increased plasma estradiol in YMSHR but had no effect in OMSHR. Mean arterial pressure (MAP) was significantly higher in OMSHR than in YMSHR and testosterone supplements decreased MAP in OMSHR, but significantly increased MAP in YMSHR. Enalapril, the angiotensin-converting enzyme inhibitor, reduced MAP in both control and testosterone-supplemented YMSHR, but had a greater effect on MAP in testosterone-treated rats, suggesting the mechanism responsible for the increase in MAP in YMSHR is mediated at least in part by activation of the renin-angiotensin system. Taken together with previous studies, these data suggest that testosterone supplements may have differential effects on men depending on age, cardiovascular and metabolic status, and dose and whether given long-term or short-term. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Ultrasoft Electronics for Hyperelastic Strain, Pressure, and Direct Curvature Sensing

NASA Astrophysics Data System (ADS)

Majidi, Carmel; Kramer, Rebecca; Wood, Robert

2011-03-01

Progress in soft robotics, wearable computing, and programmable matter demands a new class of ultrasoft electronics for tactile control, contact detection, and deformation mapping. This next generation of sensors will remain electrically functional under extreme deformation without influencing the natural mechanics of the host system. Ultrasoft strain and pressure sensing has previously been demonstrated with elastomer sheets (eg. PDMS, silicone rubber) embedded with microchannels of conductive liquid (mercury, eGaIn). Building on these efforts, we introduce a novel method for direct curvature sensing that registers the location and intensity of surface curvature. An elastomer sheet is embedded with micropatterned cavities and microchannels of conductive liquid. Bending the elastomer or placing it on a curved surface leads to a change in channel cross-section and a corresponding change in its electrical resistance. In contrast to conventional methods of curvature sensing, this approach does not depend on semi-rigid components or differential strain measurement. Direct curvature sensing completes the portfolio of sensing elements required to completely map hyperelastic deformation for future soft robotics and computing. NSF MRSEC DMR-0820484.

Algebra and topology for applications to physics

NASA Technical Reports Server (NTRS)

Rozhkov, S. S.

1987-01-01

The principal concepts of algebra and topology are examined with emphasis on applications to physics. In particular, attention is given to sets and mapping; topological spaces and continuous mapping; manifolds; and topological groups and Lie groups. The discussion also covers the tangential spaces of the differential manifolds, including Lie algebras, vector fields, and differential forms, properties of differential forms, mapping of tangential spaces, and integration of differential forms.

Relationships between cerebral autoregulation and markers of kidney and liver injury in neonatal encephalopathy and therapeutic hypothermia.

PubMed

Lee, J K; Perin, J; Parkinson, C; O'Connor, M; Gilmore, M M; Reyes, M; Armstrong, J; Jennings, J M; Northington, F J; Chavez-Valdez, R

2017-08-01

We studied whether cerebral blood pressure autoregulation and kidney and liver injuries are associated in neonatal encephalopathy (NE). We monitored autoregulation of 75 newborns who received hypothermia for NE in the neonatal intensive care unit to identify the mean arterial blood pressure with optimized autoregulation (MAP OPT ). Autoregulation parameters and creatinine, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed using adjusted regression models. Greater time with blood pressure within MAP OPT during hypothermia was associated with lower creatinine in girls. Blood pressure below MAP OPT related to higher ALT and AST during normothermia in all neonates and boys. The opposite occurred in rewarming when more time with blood pressure above MAP OPT related to higher AST. Blood pressures that optimize cerebral autoregulation may support the kidneys. Blood pressures below MAP OPT and liver injury during normothermia are associated. The relationship between MAP OPT and AST during rewarming requires further study.

Pressure Mapping in Elderly Care: A Tool to Increase Pressure Injury Knowledge and Awareness Among Staff.

PubMed

Hultin, Lisa; Olsson, Estrid; Carli, Cheryl; Gunningberg, Lena

The purpose of this study was to evaluate the use of a pressure mapping system with real-time feedback of pressure points in elderly care, with specific focus on pressure injury (PI) knowledge/attitudes (staff), interface pressure, and PI prevention activities (residents). Descriptive, 1-group pretest/posttest study. A convenience sample of 40 assistant nurses and aides participated in the study; staff members were recruited at daytime, and 1 nighttime meeting was held at the facility. A convenience sample of 12 residents with risk for PI were recruited, 4 from each ward. Inclusion criteria were participants older than 65 years, Modified Norton Scale score 20 or less, and in need of help with turning in order to prevent PI. The study setting was a care facility for the elderly in Uppsala, Sweden. A descriptive, comparative pretest/posttest study design was used. The intervention consisted of the use of a pressure mapping system, combined with theoretical and practical teaching. Theoretical and practical information related to PI prevention and the pressure mapping system was presented to the staff. The staff (n = 40) completed the Pressure Ulcer Knowledge and Assessment Tool (PUKAT) and Attitudes towards Pressure Ulcer (APuP) before and following study intervention. Residents' beds were equipped with a pressure mapping system during 7 consecutive days. Peak pressures and preventive interventions were registered 3 times a day by trained study nurses, assistant nurses, and aides. Staff members' PUKAT scores increased significantly (P = .002), while their attitude scores, which were high pretest, remained unchanged. Peak interface pressures were significantly reduced (P = .016), and more preventive interventions (n = 0.012) were implemented when the staff repositioned residents after feedback from the pressure mapping system. A limited educational intervention, combined with the use of a pressure mapping system, was successful as it improved staff members' knowledge about PI prevention, reduced interface pressure, and increased PI prevention activities. As many of the staff members lacked formal education in PI prevention and management, opportunities for teaching sessions and reflection upon PI prevention should be incorporated into the workplace. More research is needed to evaluate the effect of continuous pressure mapping on the incidence of PI.

Differential pressure sensing system for airfoils usable in turbine engines

DOEpatents

Yang, Wen-Ching; Stampahar, Maria E.

2005-09-13

A detection system for identifying airfoils having a cooling systems with orifices that are plugged with contaminants or with showerheads having a portion burned off. The detection system measures pressures at different locations and calculates or measures a differential pressure. The differential pressure may be compared with a known benchmark value to determine whether the differential pressure has changed. Changes in the differential pressure may indicate that one or more of the orifices in a cooling system of an airfoil are plugged or that portions of, or all of, a showerhead has burned off.

The kinases MEKK2 and MEKK3 regulate transforming growth factor-β-mediated helper T cell differentiation.

PubMed

Chang, Xing; Liu, Fang; Wang, Xiaofang; Lin, Aiping; Zhao, Hongyu; Su, Bing

2011-02-25

Mitogen-activated protein kinases (MAPKs) are key mediators of the T cell receptor (TCR) signals but their roles in T helper (Th) cell differentiation are unclear. Here we showed that the MAPK kinase kinases MEKK2 (encoded by Map3k2) and MEKK3 (encoded by Map3k3) negatively regulated transforming growth factor-β (TGF-β)-mediated Th cell differentiation. Map3k2(-/-)Map3k3(Lck-Cre/-) mice showed an abnormal accumulation of regulatory T (Treg) and Th17 cells in the periphery, consistent with Map3k2(-/-)Map3k3(Lck-Cre/-) naive CD4(+) T cells' differentiation into Treg and Th17 cells with a higher frequency than wild-type (WT) cells after TGF-β stimulation in vitro. In addition, Map3k2(-/-)Map3k3(Lck-Cre/-) mice developed more severe experimental autoimmune encephalomyelitis. Map3k2(-/-)Map3k3(Lck-Cre/-) T cells exhibited impaired phosphorylation of SMAD2 and SMAD3 proteins at their linker regions, which negatively regulated the TGF-β responses in T cells. Thus, the crosstalk between TCR-induced MAPK and the TGF-β signaling pathways is important in regulating Th cell differentiation. Copyright © 2011 Elsevier Inc. All rights reserved.

Super-resolution imaging using multi- electrode CMUTs: theoretical design and simulation using point targets.

PubMed

You, Wei; Cretu, Edmond; Rohling, Robert

2013-11-01

This paper investigates a low computational cost, super-resolution ultrasound imaging method that leverages the asymmetric vibration mode of CMUTs. Instead of focusing on the broadband received signal on the entire CMUT membrane, we utilize the differential signal received on the left and right part of the membrane obtained by a multi-electrode CMUT structure. The differential signal reflects the asymmetric vibration mode of the CMUT cell excited by the nonuniform acoustic pressure field impinging on the membrane, and has a resonant component in immersion. To improve the resolution, we propose an imaging method as follows: a set of manifold matrices of CMUT responses for multiple focal directions are constructed off-line with a grid of hypothetical point targets. During the subsequent imaging process, the array sequentially steers to multiple angles, and the amplitudes (weights) of all hypothetical targets at each angle are estimated in a maximum a posteriori (MAP) process with the manifold matrix corresponding to that angle. Then, the weight vector undergoes a directional pruning process to remove the false estimation at other angles caused by the side lobe energy. Ultrasound imaging simulation is performed on ring and linear arrays with a simulation program adapted with a multi-electrode CMUT structure capable of obtaining both average and differential received signals. Because the differential signals from all receiving channels form a more distinctive temporal pattern than the average signals, better MAP estimation results are expected than using the average signals. The imaging simulation shows that using differential signals alone or in combination with the average signals produces better lateral resolution than the traditional phased array or using the average signals alone. This study is an exploration into the potential benefits of asymmetric CMUT responses for super-resolution imaging.

High-Resolution Mapping of Yield Curve Shape and Evolution for Porous Rock: The Effect of Inelastic Compaction on Porous Bassanite

NASA Astrophysics Data System (ADS)

Bedford, John D.; Faulkner, Daniel R.; Leclère, Henri; Wheeler, John

2018-02-01

Porous rock deformation has important implications for fluid flow in a range of crustal settings as compaction can increase fluid pressure and alter permeability. The onset of inelastic strain for porous materials is typically defined by a yield curve plotted in differential stress (Q) versus effective mean stress (P) space. Empirical studies have shown that these curves are broadly elliptical in shape. Here conventional triaxial experiments are first performed to document (a) the yield curve of porous bassanite (porosity ≈ 27-28%), a material formed from the dehydration of gypsum, and (b) the postyield behavior, assuming that P and Q track along the yield surface as inelastic deformation accumulates. The data reveal that after initial yield, the yield surface cannot be perfectly elliptical and must evolve significantly as inelastic strain is accumulated. To investigate this further, a novel stress-probing methodology is developed to map precisely the yield curve shape and subsequent evolution for a single sample. These measurements confirm that the high-pressure side of the curve is partly composed of a near-vertical limb. Yield curve evolution is shown to be dependent on the nature of the loading path. Bassanite compacted under differential stress develops a heterogeneous microstructure and has a yield curve with a peak that is almost double that of an equal porosity sample that has been compacted hydrostatically. The dramatic effect of different loading histories on the strength of porous bassanite highlights the importance of understanding the associated microstructural controls on the nature of inelastic deformation in porous rock.

Site-specific microtubule-associated protein 4 dephosphorylation causes microtubule network densification in pressure overload cardiac hypertrophy.

PubMed

Chinnakkannu, Panneerselvam; Samanna, Venkatesababa; Cheng, Guangmao; Ablonczy, Zsolt; Baicu, Catalin F; Bethard, Jennifer R; Menick, Donald R; Kuppuswamy, Dhandapani; Cooper, George

2010-07-09

In severe pressure overload-induced cardiac hypertrophy, a dense, stabilized microtubule network forms that interferes with cardiocyte contraction and microtubule-based transport. This is associated with persistent transcriptional up-regulation of cardiac alpha- and beta-tubulin and microtubule-stabilizing microtubule-associated protein 4 (MAP4). There is also extensive microtubule decoration by MAP4, suggesting greater MAP4 affinity for microtubules. Because the major determinant of this affinity is site-specific MAP4 dephosphorylation, we characterized this in hypertrophied myocardium and then assessed the functional significance of each dephosphorylation site found by mimicking it in normal cardiocytes. We first isolated MAP4 from normal and pressure overload-hypertrophied feline myocardium; volume-overloaded myocardium, which has an equal degree and duration of hypertrophy but normal functional and cytoskeletal properties, served as a control for any nonspecific growth-related effects. After cloning cDNA-encoding feline MAP4 and obtaining its deduced amino acid sequence, we characterized by mass spectrometry any site-specific MAP4 dephosphorylation. Solely in pressure overload-hypertrophied myocardium, we identified striking MAP4 dephosphorylation at Ser-472 in the MAP4 N-terminal projection domain and at Ser-924 and Ser-1056 in the assembly-promoting region of the C-terminal microtubule-binding domain. Site-directed mutagenesis of MAP4 cDNA was then used to switch each serine to non-phosphorylatable alanine. Wild-type and mutated cDNAs were used to construct adenoviruses; microtubule network density, stability, and MAP4 decoration were assessed in normal cardiocytes following an equivalent level of MAP4 expression. The Ser-924 --> Ala MAP4 mutant produced a microtubule phenotype indistinguishable from that seen in pressure overload hypertrophy, such that Ser-924 MAP4 dephosphorylation during pressure overload hypertrophy may be central to this cytoskeletal abnormality.

Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

NASA Technical Reports Server (NTRS)

Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor); Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor)

2016-01-01

A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

Identification of hypertension-related genes through an integrated genomic-transcriptomic approach.

PubMed

Yagil, Chana; Hubner, Norbert; Monti, Jan; Schulz, Herbert; Sapojnikov, Marina; Luft, Friedrich C; Ganten, Detlev; Yagil, Yoram

2005-04-01

In search for the genetic basis of hypertension, we applied an integrated genomic-transcriptomic approach to identify genes involved in the pathogenesis of hypertension in the Sabra rat model of salt-susceptibility. In the genomic arm of the project, we previously detected in male rats two salt-susceptibility QTLs on chromosome 1, SS1a (D1Mgh2-D1Mit11; span 43.1 cM) and SS1b (D1Mit11-D1Mit4; span 18 cM). In the transcriptomic arm, we studied differential gene expression in kidneys of SBH/y and SBN/y rats that had been fed regular diet or salt-loaded. We used the Affymetrix Rat Genome RAE230 GeneChip and probed >30,000 transcripts. The research algorithm called for an initial genome-wide screen for differentially expressed transcripts between the study groups. This step was followed by cluster analysis based on 2x2 ANOVA to identify transcripts that were of relevance specifically to salt-sensitivity and hypertension and to salt-resistance. The two arms of the project were integrated by identifying those differentially expressed transcripts that showed an allele-specific hypertensive effect on salt-loading and that mapped within the defined boundaries of the salt-susceptibility QTLs on chromosome 1. The differentially expressed transcripts were confirmed by RT-PCR. Of the 2933 genes annotated to rat chromosome 1, 1102 genes were identified within the boundaries of the two blood pressure QTLs. The microarray identified 2470 transcripts that were differentially expressed between the study groups. Cluster analysis identified genome-wide 192 genes that were relevant to salt-susceptibility and/or hypertension, 19 of which mapped to chromosome 1. Eight of these genes mapped within the boundaries of QTLs SS1a and SS1b. RT-PCR confirmed 7 genes, leaving TcTex1, Myadm, Lisch7, Axl-like, Fah, PRC1-like, and Serpinh1. None of these genes has been implicated in hypertension before. These genes become henceforth targets for our continuing search for the genetic basis of hypertension.

Noninvasive measurement of beat-to-beat arterial blood pressure by the Korotkoff sound delay time.

PubMed

Xiang, Haiyan; Liu, Yanyong; Li, Yinhua; Qin, Yufei; Yu, Mengsun

2012-02-01

To propose a novel noninvasive beat-to-beat arterial blood pressure measurement method based on the Korotkoff sound delay time (KDT) and evaluate its accuracy in preliminary experiments. KDT decreases as the cuff pressure P deflates, which can be described by a function KDT=f (P). Actually, KDT is a function of arterial transmural pressure. Therefore, the variation in blood pressure can be obtained by the transmural pressure, which is estimated by the KDT. Holding the cuff pressure at an approximate constant pressure between systolic pressure and diastolic pressure, the variation in blood pressure ΔEBP between successive heartbeats can be estimated according to KDT and f'(p), which represents the variation of KDT corresponding to unit pressure. Then the blood pressure for each heartbeat can be obtained by accumulating the ΔEBP. Invasive and noninvasive blood pressure values of six participants were measured simultaneously to evaluate the method. The average of the correlation coefficients between the invasive mean arterial pressure (MAP) and the KDT for six participants was -0.91. The average of the correlation coefficients between the invasive MAP and the estimated mean blood pressure (EBP) was 0.92. The mean difference between EBP and MAP was 0.51 mmHg, and the SD was 2.65 mmHg. The mean blood pressure estimated by the KDT is consistent with the invasive MAP. The beat-to-beat blood pressure estimated by KDT provides an accurate estimate of MAP in the preliminary experiments and represents a potential acceptable alternative to invasive blood pressure monitoring during laboratory studies.

High accuracy differential pressure measurements using fluid-filled catheters - A feasibility study in compliant tubes.

PubMed

Rotman, Oren Moshe; Weiss, Dar; Zaretsky, Uri; Shitzer, Avraham; Einav, Shmuel

2015-09-18

High accuracy differential pressure measurements are required in various biomedical and medical applications, such as in fluid-dynamic test systems, or in the cath-lab. Differential pressure measurements using fluid-filled catheters are relatively inexpensive, yet may be subjected to common mode pressure errors (CMP), which can significantly reduce the measurement accuracy. Recently, a novel correction method for high accuracy differential pressure measurements was presented, and was shown to effectively remove CMP distortions from measurements acquired in rigid tubes. The purpose of the present study was to test the feasibility of this correction method inside compliant tubes, which effectively simulate arteries. Two tubes with varying compliance were tested under dynamic flow and pressure conditions to cover the physiological range of radial distensibility in coronary arteries. A third, compliant model, with a 70% stenosis severity was additionally tested. Differential pressure measurements were acquired over a 3 cm tube length using a fluid-filled double-lumen catheter, and were corrected using the proposed CMP correction method. Validation of the corrected differential pressure signals was performed by comparison to differential pressure recordings taken via a direct connection to the compliant tubes, and by comparison to predicted differential pressure readings of matching fluid-structure interaction (FSI) computational simulations. The results show excellent agreement between the experimentally acquired and computationally determined differential pressure signals. This validates the application of the CMP correction method in compliant tubes of the physiological range for up to intermediate size stenosis severity of 70%. Copyright © 2015 Elsevier Ltd. All rights reserved.

STE/ICE (Simplified Test Equipment/Internal Combustion Engines) Design Guide for Vehicle Diagnostic Connector Assemblies

DTIC Science & Technology

1982-08-01

19 3.2 Diesel Engine Speed Transducer 20 3.3 Pressure Transducer 20 3.4 Temperature Transducer 22 3.5 Differential Pressure Switch 22 3.6 Differential... Pressure Switch , Multi-Point 22 3.7 Current Measurement Transducer 23 - 3.8 Electrolyte Level Probes 23 3.9 Diagnostic Connector 24 3.10 Harness...12258933 Differential Pressure Switch - Multi-point 12258934 K -. Differential Pressure Switch 12258938 Electrolyte Level Sensor 12258935 Shunt 1000

Simultaneous Luminescence Pressure and Temperature Mapping

NASA Technical Reports Server (NTRS)

Buck, Gregory M. (Inventor)

1998-01-01

A simultaneous luminescence pressure and temperature mapping system is developed including improved dye application techniques for surface temperature and pressure measurements from 5 torr to 1000 torr with possible upgrade to from 0.5 torr to several atmospheres with improved camera resolution. Adsorbed perylene dye on slip-cast silica is pressure (oxygen) sensitive and reusable to relatively high temperatures (-150 C). Adsorbed luminescence has an approximately linear color shift with temperature, which can be used for independent temperature mapping and brightness pressure calibration with temperature.

Simultaneous Luminescence Pressure and Temperature Mapping System

NASA Technical Reports Server (NTRS)

Buck, Gregory M. (Inventor)

1995-01-01

A simultaneous luminescence pressure and temperature mapping system is developed including improved dye application techniques for surface temperature and pressure measurements from 5 torr to 1000 torr with possible upgrade to from 0.5 torr to several atmospheres with improved camera resolution. Adsorbed perylene dye on slip-cast silica is pressure (oxygen) sensitive and reusable to relatively high temperatures (approximately 150 C). Adsorbed luminescence has an approximately linear color shift with temperature, which can be used for independent temperature mapping and brightness pressure calibration with temperature.

Investigation of the Martian environment by infrared spectroscopy on Mariner 9

NASA Technical Reports Server (NTRS)

Conrath, H. R.; Conrath, B. J.; Novis, W.; Kunde, V. G.; Lowman, P.; Maguire, W.; Pearl, J. C.; Pirraglia, J.; Prabhakara, C.; Schlachman, B.

1972-01-01

Measurements obtained during and after the planet-wide dust storm indicate that large diurnal variations in atmospheric temperature existed up to at least 30 km; winds inferred from the temperature fields show a strong tidal component and significant ageostrophic behavior. With the dissipation of the dust, the daily maximum in the atmospheric temperature field moved from approximately latitude -60 and late afternoon local time to near the subsolar point in latitude and time. Analysis of spectral features due to the atmospheric dust indicates as SIO2 content of 60 ? 10%, implying that substantial geochemical differentiation has occurred. Water vapor estimates indicate abundances of 10 to 20 precipitable micrometers. Between November 1971 and April 1972 no gross latitudinal or temporal dependence in the water vapor distribution was detected from the south polar region to the equator. Water vapor was not detected over the north polar regions. Surface pressure mapping was carried out from which topographic relief of nearly two pressure scale heights is inferred. Extensive regions were found where the surface pressure exceeds the triple point pressure of water.

A novel isoform of MAP4 organises the paraxial microtubule array required for muscle cell differentiation

PubMed Central

Mogessie, Binyam; Roth, Daniel; Rahil, Zainab; Straube, Anne

2015-01-01

The microtubule cytoskeleton is critical for muscle cell differentiation and undergoes reorganisation into an array of paraxial microtubules, which serves as template for contractile sarcomere formation. In this study, we identify a previously uncharacterised isoform of microtubule-associated protein MAP4, oMAP4, as a microtubule organising factor that is crucial for myogenesis. We show that oMAP4 is expressed upon muscle cell differentiation and is the only MAP4 isoform essential for normal progression of the myogenic differentiation programme. Depletion of oMAP4 impairs cell elongation and cell–cell fusion. Most notably, oMAP4 is required for paraxial microtubule organisation in muscle cells and prevents dynein- and kinesin-driven microtubule–microtubule sliding. Purified oMAP4 aligns dynamic microtubules into antiparallel bundles that withstand motor forces in vitro. We propose a model in which the cooperation of dynein-mediated microtubule transport and oMAP4-mediated zippering of microtubules drives formation of a paraxial microtubule array that provides critical support for the polarisation and elongation of myotubes. DOI: http://dx.doi.org/10.7554/eLife.05697.001 PMID:25898002

Icariside II Promotes the Differentiation of Adipose Tissue-Derived Stem Cells to Schwann Cells to Preserve Erectile Function after Cavernous Nerve Injury.

PubMed

Zheng, Tao; Zhang, Tian-Biao; Wang, Chao-Liang; Zhang, Wei-Xing; Jia, Dong-Hui; Yang, Fan; Sun, Yang-Yang; Ding, Xiao-Ju; Wang, Rui

2018-06-14

Icariside II (ICA II) is used in erectile dysfunction treatment. Adipose tissue-derived stem cells (ADSCs) are efficient at improving erectile function. This study aimed to explore the action mechanism of ADSCs in improving erectile function. ADSCs were isolated from the adipose tissues of rats. Cell proliferation was determined using the Cell Counting Kit-8 (CCK-8) assay. The expressions of mRNA and protein were determined separately through qRT-PCR and western blot. The endogenous expressions of related genes were regulated using recombinant plasmids and cell transfection. A Dual- Luciferase Reporter Assay was performed to determine the interaction between miR-34a and STAT3. Rat models with bilateral cavernous nerve injuries (BCNIs) were used to assess erectile function through the detection of mean arterial pressure (MAP) and intracavernosal pressure (ICP). ICA II promoted ADSCs' proliferation and differentiation to Schwann cells (SCs) through the inhibition of miR-34a. Suppressed miR-34a promoted the differentiation of ADSCs to SCs by upregulating STAT3. ICA II promoted the differentiation of ADSCs to SCs through the miR-34a/STAT3 pathway. The combination of ICA II and ADSCs preserved the erectile function of the BCNI model rats. ADSCs treated with ICA II markedly preserved the erectile function of the BCNI model rats, which was reversed through miR-34a overexpression. ICA II promotes the differentiation of ADSCs to SCs through the miR- 34a/STAT3 pathway, contributing to erectile function preservation after the occurrence of a cavernous nerve injury.

Cyclooxygenases 1 and 2 Differentially Regulate Blood Pressure and Cerebrovascular Responses to Acute and Chronic Intermittent Hypoxia: Implications for Sleep Apnea

PubMed Central

Beaudin, Andrew E.; Pun, Matiram; Yang, Christina; Nicholl, David D. M.; Steinback, Craig D.; Slater, Donna M.; Wynne‐Edwards, Katherine E.; Hanly, Patrick J.; Ahmed, Sofia B.; Poulin, Marc J.

2014-01-01

Background Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular and cerebrovascular disease resulting from intermittent hypoxia (IH)‐induced inflammation. Cyclooxygenase (COX)‐formed prostanoids mediate the inflammatory response, and regulate blood pressure and cerebral blood flow (CBF), but their role in blood pressure and CBF responses to IH is unknown. Therefore, this study's objective was to determine the role of prostanoids in cardiovascular and cerebrovascular responses to IH. Methods and Results Twelve healthy, male participants underwent three, 6‐hour IH exposures. For 4 days before each IH exposure, participants ingested a placebo, indomethacin (nonselective COX inhibitor), or Celebrex® (selective COX‐2 inhibitor) in a double‐blind, randomized, crossover study design. Pre‐ and post‐IH blood pressure, CBF, and urinary prostanoids were assessed. Additionally, blood pressure and urinary prostanoids were assessed in newly diagnosed, untreated OSA patients (n=33). Nonselective COX inhibition increased pre‐IH blood pressure (P≤0.04) and decreased pre‐IH CBF (P=0.04) while neither physiological variable was affected by COX‐2 inhibition (P≥0.90). Post‐IH, MAP was elevated (P≤0.05) and CBF was unchanged with placebo and nonselective COX inhibition. Selective COX‐2 inhibition abrogated the IH‐induced MAP increase (P=0.19), but resulted in lower post‐IH CBF (P=0.01). Prostanoids were unaffected by IH, except prostaglandin E2 was elevated with the placebo (P=0.02). Finally, OSA patients had elevated blood pressure (P≤0.4) and COX‐1 formed thromboxane A2 concentrations (P=0.02). Conclusions COX‐2 and COX‐1 have divergent roles in modulating vascular responses to acute and chronic IH. Moreover, COX‐1 inhibition may mitigate cardiovascular and cerebrovascular morbidity in OSA. Clinical Trial Registration URL: www.clinicaltrials.gov. Unique identifier: NCT01280006 PMID:24815497

Flow behaviour of supercritical CO2 and brine in Berea sandstone during drainage and imbibition revealed by medical X-ray CT images

NASA Astrophysics Data System (ADS)

Zhang, Yi; Nishizawa, Osamu; Kiyama, Tamotsu; Chiyonobu, Shun; Xue, Ziqiu

2014-06-01

We injected Berea sandstone with supercritical CO2 and imaged the results with a medical X-ray computed tomography (CT) scanner. The images were acquired by injecting CO2 into a core of brine-saturated sandstone (drainage), and additional images were acquired during reinjection of brine (imbibition) after drainage. We then analysed the temporal variations of CO2 saturation maps obtained from the CT images. The experiments were performed under a confining pressure of 12 MPa, a pore pressure of 10 MPa and a temperature of 40 °C. Porosity and CO2 saturation were calculated for each image voxel of the rock on the basis of the Hounsfield unit values (CT numbers) measured at three states of saturation: dry, full brine saturation and full CO2 saturation. The saturation maps indicated that the distributions of CO2 and brine were controlled by the sub-core-scale heterogeneities which consisted of a laminated structure (bedding) with high- and low-porosity layers. During drainage, CO2 preferentially flowed through the high-porosity layers where most of the CO2 was entrapped during low flow-rate imbibition. The entrapped CO2 was flushed out when high flow-rate imbibition commenced. Plots of the voxel's CT number against porosity revealed the relationship between fluid replacement and porosity. By reference to the CT numbers at the full brine-saturated stage, differential CT numbers were classified into three bins corresponding to voxel porosity: high, medium and low porosity. Distributions of the differential CT number for the three porosity bins were bimodal and in order with respect to the porosity bins during both drainage and imbibitions; however, the order differed between the two stages. This difference suggested that different replacement mechanisms operated for the two processes. Spatial autocorrelation of CO2 saturation maps on sections perpendicular to the flow direction revealed remarkable changes during passage of the replacement fronts during both drainage and imbibition, changes reflecting the interfingering pattern across the replacement fronts. Although the permeability differences between high- and low-porosity layers were not sufficiently large to disturb the uniform flow of brine, the CO2 concentration in the high-porosity layers may have been caused by the differences of capillary pressure between wide and narrow pore throats, perhaps enhanced by an invasion percolation mechanism in flow-path networks.

Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones

NASA Astrophysics Data System (ADS)

Nakajima, Hideko Heidi; Dong, Wei; Olson, Elizabeth S.; Merchant, Saumil N.; Ravicz, Michael E.; Rosowski, John J.

2009-02-01

We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human cadaveric temporal bones. Micro-scale fiberoptic pressure sensors enabled the study of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving cochlear waves and auditory transduction. Results showed that: pressure of scala vestibuli was much greater than scala tympani except at low and high frequencies where scala tympani pressure affects the input to the cochlea; the differential pressure proved to be an excellent measure of normal ossicular transduction of sound (shown to decrease 30-50 dB with ossicular disarticulation, whereas the individual scala pressures were significantly affected by non-ossicular conduction of sound at high frequencies); the middle-ear gain and differential pressure were generally bandpass in frequency dependence; and the middle-ear delay in the human was over twice that of the gerbil. Concurrent stapes velocity measurements allowed determination of the differential impedance across the partition and round-window impedance. The differential impedance was generally resistive, while the round-window impedance was consistent with a compliance in conjunction with distributed inertia and damping. Our techniques can be used to study inner-ear conductive pathologies (e.g., semicircular dehiscence), as well as non-ossicular cochlear stimulation (e.g., round-window stimulation) - situations that cannot be completely quantified by measurements of stapes velocity or scala-vestibuli pressure by themselves.

Recapitulation of genome-wide association studies on pulse pressure and mean arterial pressure in the Korean population.

PubMed

Hong, Kyung-Won; Min, Haesook; Heo, Byeong-Mun; Joo, Seong Eun; Kim, Sung Soo; Kim, Yeonjung

2012-06-01

Increased pulse pressure (PP) and decreased mean arterial pressure (MAP) are strong prognostic predictors of adverse cardiovascular events. Recently, the International Consortium for Blood Pressure Genome-Wide Association Studies (ICBP-GWAS) reported eight loci that influenced PP and MAP. The ICBP-GWAS examined 51 cohorts--comprising 122 671 individuals of European ancestry--and identified eight SNPs: five that governed PP and three that controlled MAP. Six of these loci were novel. To replicate these newly identified loci and examine genetic architecture of PP and MAP between European and Asian populations, we conducted a meta-analysis of the eight SNPs combining data from ICBP and general population-based Korean cohorts. Two SNPs (rs13002573 (FIGN) and rs871606 (CHIC2)) for PP and two SNPs (rs1446468 (FIGN) and rs319690 (MAP4)) for MAP were replicated in Koreans. Although our GWAS only found moderate association, we believe that the findings promote us to propose that a similar genetic architecture governs PP and MAP in Asians and Europeans. However, further studies will be needed to confirm the possibility using other Asian population.

Implanted Blood-Pressure-Measuring Device

NASA Technical Reports Server (NTRS)

Fischell, Robert E.

1988-01-01

Arterial pressure compared with ambient bodily-fluid pressure. Implanted apparatus, capable of measuring blood pressure of patient, includes differential-pressure transducer connected to pressure sensor positioned in major artery. Electrical signal is function of differential pressure between blood-pressure sensor and reference-pressure sensor transmitted through skin of patient to recorder or indicator.

Rapid resetting of rabbit aortic baroreceptors and reflex heart rate responses by directional changes in blood pressure.

PubMed

Burke, S L; Dorward, P K; Korner, P I

1986-09-01

In both anaesthetized and conscious rabbits, perivascular balloon inflations slowly raised or lowered mean arterial pressure (M.A.P.), at 1-2 mmHg/s, from resting to various plateau pressures. Deflations then returned the M.A.P. to resting. 'Steady-state' curves relating M.A.P. to unitary aortic baroreceptor firing, integrated aortic nerve activity and heart rate were derived during the primary and return pressure changes and they formed typical hysteresis loops. In single units, return M.A.P.-frequency curves were shifted in the same direction as the primary pressure changes by an average 0.37 mmHg per mmHg change in M.A.P. Shifts were linearly related to the changes in M.A.P. between resting and plateau levels for all pressure rises and for falls less than 30 mmHg. They were established within 30 s and were quantitatively similar to the rapid resetting of baroreceptor function curves found 15 min-2 h after a change in resting M.A.P. (Dorward, Andresen, Burke, Oliver & Korner, 1982). Unit threshold pressures were shifted within 20 s to the same extent as the over-all curve shift to which they contributed. In the whole aortic nerve, return M.A.P.-integrated activity curves were shifted to same degree as unit function curves in both anaesthetized and conscious rabbits. Simultaneous shifts of return reflex M.A.P.-heart rate curves were also seen in conscious rabbits within 30 s. During M.A.P. falls, receptor and reflex hysteresis was similar, but during M.A.P. rises, reflex shifts were double baroreceptor shifts, suggesting the involvement of other pressure-sensitive receptors. We conclude that hysteresis shifts in baroreceptor function curves, which follow the reversal of slow ramp changes in blood pressure are a form of rapid resetting. They are accompanied by rapid resetting of reflex heart rate responses. We regard this as an important mechanism in blood pressure control which produces relatively high-gain reflex responses, during slow directional pressure changes, over a wider range of absolute pressure levels than would otherwise be possible.

Site-specific Microtubule-associated Protein 4 Dephosphorylation Causes Microtubule Network Densification in Pressure Overload Cardiac Hypertrophy*

PubMed Central

Chinnakkannu, Panneerselvam; Samanna, Venkatesababa; Cheng, Guangmao; Ablonczy, Zsolt; Baicu, Catalin F.; Bethard, Jennifer R.; Menick, Donald R.; Kuppuswamy, Dhandapani; Cooper, George

2010-01-01

In severe pressure overload-induced cardiac hypertrophy, a dense, stabilized microtubule network forms that interferes with cardiocyte contraction and microtubule-based transport. This is associated with persistent transcriptional up-regulation of cardiac α- and β-tubulin and microtubule-stabilizing microtubule-associated protein 4 (MAP4). There is also extensive microtubule decoration by MAP4, suggesting greater MAP4 affinity for microtubules. Because the major determinant of this affinity is site-specific MAP4 dephosphorylation, we characterized this in hypertrophied myocardium and then assessed the functional significance of each dephosphorylation site found by mimicking it in normal cardiocytes. We first isolated MAP4 from normal and pressure overload-hypertrophied feline myocardium; volume-overloaded myocardium, which has an equal degree and duration of hypertrophy but normal functional and cytoskeletal properties, served as a control for any nonspecific growth-related effects. After cloning cDNA-encoding feline MAP4 and obtaining its deduced amino acid sequence, we characterized by mass spectrometry any site-specific MAP4 dephosphorylation. Solely in pressure overload-hypertrophied myocardium, we identified striking MAP4 dephosphorylation at Ser-472 in the MAP4 N-terminal projection domain and at Ser-924 and Ser-1056 in the assembly-promoting region of the C-terminal microtubule-binding domain. Site-directed mutagenesis of MAP4 cDNA was then used to switch each serine to non-phosphorylatable alanine. Wild-type and mutated cDNAs were used to construct adenoviruses; microtubule network density, stability, and MAP4 decoration were assessed in normal cardiocytes following an equivalent level of MAP4 expression. The Ser-924 → Ala MAP4 mutant produced a microtubule phenotype indistinguishable from that seen in pressure overload hypertrophy, such that Ser-924 MAP4 dephosphorylation during pressure overload hypertrophy may be central to this cytoskeletal abnormality. PMID:20436166

State-resolved differential cross-section measurement of Cl+C 2H 6→HCl+C 2H 5 reaction using single-beam velocity mapping

NASA Astrophysics Data System (ADS)

Samartzis, Peter C.; Smith, Derek J.; Rakitzis, T. Peter; Kitsopoulos, Theofanis N.

2000-07-01

The bimolecular reaction of atomic chlorine with ethane at a collision energy of 0.36 eV is studied in a single-beam experiment, using velocity mapping of a state-selected reaction product. The differential cross-section for HCl( v=0, J=1) product is directly determined from its Abel-inverted velocity map image. Our results are similar to previous measurements of the differential cross-section and suggest that the HCl( v=0, J=1) scattering is broad with a side-scattered peak. This Letter demonstrates the power of velocity mapping for measuring differential cross-sections for reactions for which one of the reactants is produced photolytically.

A program to evaluate a control system based on feedback of aerodynamic pressure differentials

NASA Technical Reports Server (NTRS)

Levy, D. W.; Finn, P.; Roskam, J.

1981-01-01

The use of aerodynamic pressure differentials to position a control surface is evaluated. The system is a differential pressure command loop, analogous to a position command loop, where the surface is commanded to move until a desired differential pressure across the surface is achieved. This type of control is more direct and accurate because it is the differential pressure which causes the control forces and moments. A frequency response test was performed in a low speed wind tunnel to measure the performance of the system. Both pressure and position feedback were tested. The pressure feedback performed as well as position feedback implying that the actuator, with a break frequency on the order of 10 Rad/sec, was the limiting component. Theoretical considerations indicate that aerodynamic lags will not appear below frequencies of 50 Rad/sec, or higher.

EIT-based fabric pressure sensing.

PubMed

Yao, A; Yang, C L; Seo, J K; Soleimani, M

2013-01-01

This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results.

Selective stabilization of tau in axons and microtubule-associated protein 2C in cell bodies and dendrites contributes to polarized localization of cytoskeletal proteins in mature neurons.

PubMed

Hirokawa, N; Funakoshi, T; Sato-Harada, R; Kanai, Y

1996-02-01

In mature neurons, tau is abundant in axons, whereas microtubule-associated protein 2 (MAP2) and MAP2C are specifically localized in dendrites. Known mechanisms involved in the compartmentalization of these cytoskeletal proteins include the differential localization of mRNA (MAP2 mRNA in dendrites, MAP2C mRNA in cell body, and Tau mRNA in proximal axon revealed by in situ hybridization) (Garner, C.C., R.P. Tucker, and A. Matus. 1988. Nature (Lond.). 336:674-677; Litman, P., J. Barg, L. Rindzooski, and I. Ginzburg. 1993. Neuron. 10:627-638), suppressed transit of MAP2 into axons (revealed by cDNA transfection into neurons) (Kanai, Y., and N. Hirokawa. 1995. Neuron. 14:421-432), and differential turnover of MAP2 in axons vs dendrites (Okabe, S., and N. Hirokawa. 1989. Proc. Natl. Acad. Sci. USA. 86:4127-4131). To investigate whether differential turnover of MAPs contributes to localization of other major MAPs in general, we microinjected biotinylated tau, MAP2C, or MAP2 into mature spinal cord neurons in culture (approximately 3 wk) and then analyzed their fates by antibiotin immunocytochemistry. Initially, each was detected in axons and dendrites, although tau persisted only in axons, whereas MAP2C and MAP2 were restricted to cell bodies and dendrites. Injected MAP2C and MAP2 bound to dendritic microtubules more firmly than to microtubules in axons, while injected tau bound to axonal microtubules more firmly than to microtubules in dendrites. Thus, beyond contributions from mRNA localization and selective axonal transport, compartmentalization of each of the three major MAPs occurs through local differential turnover.

Evaluation of MIL-L-23699 Lubricant Performance in the TF41-A-2 Engine

DTIC Science & Technology

1975-05-01

provides the necessary signals to the cockpit indicator for the indication of engine oil pressure. The differential pressure switch controls a cockpit...light. If the light is on, it indicates that the differential oil pressure is low. The setting ot the differential pressure switch is 11 t 1 psi. The

Global terrestrial Human Footprint maps for 1993 and 2009

PubMed Central

Venter, Oscar; Sanderson, Eric W.; Magrach, Ainhoa; Allan, James R.; Beher, Jutta; Jones, Kendall R.; Possingham, Hugh P.; Laurance, William F.; Wood, Peter; Fekete, Balázs M.; Levy, Marc A.; Watson, James E.M.

2016-01-01

Remotely-sensed and bottom-up survey information were compiled on eight variables measuring the direct and indirect human pressures on the environment globally in 1993 and 2009. This represents not only the most current information of its type, but also the first temporally-consistent set of Human Footprint maps. Data on human pressures were acquired or developed for: 1) built environments, 2) population density, 3) electric infrastructure, 4) crop lands, 5) pasture lands, 6) roads, 7) railways, and 8) navigable waterways. Pressures were then overlaid to create the standardized Human Footprint maps for all non-Antarctic land areas. A validation analysis using scored pressures from 3114×1 km2 random sample plots revealed strong agreement with the Human Footprint maps. We anticipate that the Human Footprint maps will find a range of uses as proxies for human disturbance of natural systems. The updated maps should provide an increased understanding of the human pressures that drive macro-ecological patterns, as well as for tracking environmental change and informing conservation science and application. PMID:27552448

The relationship between oxidized serum albumin and blood pressure in hypoalbuminemic peritoneal dialysis patients.

PubMed

Hasan, Kamal; Hassan, Fadi; Michelis, Regina

2017-01-01

Oxidative stress produces molecular modifications of serum albumin that disturb its biological functions and interfere with its detection by the bromocresol green assay (BCG). Oxidative stress, inflammation, and hypoalbuminemia are common peritoneal dialysis (PD). This study aimed to evaluate the relationship between serum albumin, oxidized serum albumin (OSA), oncotic pressure, and blood pressure in hypoalbuminemic PD patients. Twenty-four PD patients with serum albumin levels <3.5 g/dl enrolled in the study. Data were compared between participants with the mean arterial pressure (MAP) <105 mmHg (n = 12) and MAP ≥ 105 mmHg (n = 12). Serum albumin levels were ≤3.0 g/dl and similar in both groups (p = 0.298). The calculated OSA and oncotic pressure were significantly higher in patients with MAP ≥ 105 mmHg than in those with MAP < 105 mmHg. MAP was positively and marginally correlated with serum albumin levels (measured by BCG) (r = 0.34, p = 0.05), and positively and significantly correlated with the calculated OSA and oncotic pressure (r = 0.44, p = 0.015, r = 0.58, p = 0.002; respectively). The oncotic pressure was positively correlated with the calculated OSA (r = 0.47, p = 0.011). OSA, undetectable by the commonly used BCG, may contribute to higher blood pressure in hypoalbuminemic PD patients.

Mice from lines selectively bred for high voluntary wheel running exhibit lower blood pressure during withdrawal from wheel access.

PubMed

Kolb, Erik M; Kelly, Scott A; Garland, Theodore

2013-03-15

Exercise is known to be rewarding and have positive effects on mental and physical health. Excessive exercise, however, can be the result of an underlying behavioral/physiological addiction. Both humans who exercise regularly and rodent models of exercise addiction sometimes display behavioral withdrawal symptoms, including depression and anxiety, when exercise is denied. However, few studies have examined the physiological state that occurs during this withdrawal period. Alterations in blood pressure (BP) are common physiological indicators of withdrawal in a variety of addictions. In this study, we examined exercise withdrawal in four replicate lines of mice selectively bred for high voluntary wheel running (HR lines). Mice from the HR lines run almost 3-fold greater distances on wheels than those from non-selected control lines, and have altered brain activity as well as increased behavioral despair when wheel access is removed. We tested the hypothesis that male HR mice have an altered cardiovascular response (heart rate, systolic, diastolic, and mean arterial pressure [MAP]) during exercise withdrawal. Measurements using an occlusion tail-cuff system were taken during 8 days of baseline, 6 days of wheel access, and 2 days of withdrawal (wheel access blocked). During withdrawal, HR mice had significantly lower systolic BP, diastolic BP, and MAP than controls, potentially indicating a differential dependence on voluntary wheel running in HR mice. This is the first characterization of a cardiovascular withdrawal response in an animal model of high voluntary exercise. Copyright © 2013. Published by Elsevier Inc.

Fracture Sustainability Pressure, Temperature, Differential Pressure, and Aperture Closure Data

DOE Data Explorer

Tim Kneafsey

2016-09-30

In these data sets, the experiment time, actual date and time, room temperature, sample temperature, upstream and downstream pressures (measured independently), corrected differential pressure (measured independently and corrected for offset and room temperature) indication of aperture closure by linear variable differential transformer are presented. An indication of the sample is in the file name and in the first line of data.

Metabolic Predictors of Change in Vascular Function: Prospective Associations From a Community-Based Cohort.

PubMed

Zachariah, Justin P; Rong, Jian; Larson, Martin G; Hamburg, Naomi M; Benjamin, Emelia J; Vasan, Ramachandran S; Mitchell, Gary F

2018-02-01

Vascular function varies with age because of physiological and pathological factors. We examined relations of longitudinal change in vascular function with change in metabolic traits. Longitudinal changes in vascular function and metabolic traits were examined in 5779 participants (mean age, 49.8±14.5 years; 54% women) who attended sequential examinations of the Framingham Offspring, Third Generation, and Omni-1 and Omni-2 cohorts. Multivariable regression analysis related changes in vascular measures (dependent variables), including carotid-femoral pulse wave velocity (CFPWV), forward pressure wave amplitude, characteristic impedance, central pulse pressure, and mean arterial pressure (MAP), with change in body mass index, fasting total:high-density lipoprotein cholesterol ratio, serum triglycerides, and blood glucose. Analyses accounted for baseline value of each vascular and metabolic measure, MAP change, and multiple comparisons. On follow-up (mean, 5.9±0.6 years), aortic stiffness (CFPWV, 0.2±1.6 m/s), and pressure pulsatility (forward pressure wave, 1.2±12.4 mm Hg; characteristic impedance, 23±73 dyne×sec/cm 5 ; central pulse pressure, 2.6±14.7 mm Hg; all P <0.0001) increased, whereas MAP fell (-3±10 mm Hg; P <0.0001). Worsening of each metabolic trait was associated with increases in CFPWV and MAP ( P <0.0001 for all associations) and an increase in MAP was associated with an increase in CFPWV. Overall, worsening metabolic traits were associated with worsening aortic stiffness and MAP. Opposite net change in aortic stiffness and MAP suggests that factors other than distending pressure contributed to the observed increase in aortic stiffness. Change in metabolic traits explained a greater proportion of the change in CFPWV and MAP than baseline metabolic values. © 2017 American Heart Association, Inc.

DiffNet: automatic differential functional summarization of dE-MAP networks.

PubMed

Seah, Boon-Siew; Bhowmick, Sourav S; Dewey, C Forbes

2014-10-01

The study of genetic interaction networks that respond to changing conditions is an emerging research problem. Recently, Bandyopadhyay et al. (2010) proposed a technique to construct a differential network (dE-MAPnetwork) from two static gene interaction networks in order to map the interaction differences between them under environment or condition change (e.g., DNA-damaging agent). This differential network is then manually analyzed to conclude that DNA repair is differentially effected by the condition change. Unfortunately, manual construction of differential functional summary from a dE-MAP network that summarizes all pertinent functional responses is time-consuming, laborious and error-prone, impeding large-scale analysis on it. To this end, we propose DiffNet, a novel data-driven algorithm that leverages Gene Ontology (go) annotations to automatically summarize a dE-MAP network to obtain a high-level map of functional responses due to condition change. We tested DiffNet on the dynamic interaction networks following MMS treatment and demonstrated the superiority of our approach in generating differential functional summaries compared to state-of-the-art graph clustering methods. We studied the effects of parameters in DiffNet in controlling the quality of the summary. We also performed a case study that illustrates its utility. Copyright © 2014 Elsevier Inc. All rights reserved.

Constant-Differential-Pressure Two-Fluid Accumulator

NASA Technical Reports Server (NTRS)

Piecuch, Benjamin; Dalton, Luke T.

2010-01-01

A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system.

EIT-Based Fabric Pressure Sensing

PubMed Central

Yao, A.; Yang, C. L.; Seo, J. K.; Soleimani, M.

2013-01-01

This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results. PMID:23533538

Schwarz maps of algebraic linear ordinary differential equations

NASA Astrophysics Data System (ADS)

Sanabria Malagón, Camilo

2017-12-01

A linear ordinary differential equation is called algebraic if all its solution are algebraic over its field of definition. In this paper we solve the problem of finding closed form solution to algebraic linear ordinary differential equations in terms of standard equations. Furthermore, we obtain a method to compute all algebraic linear ordinary differential equations with rational coefficients by studying their associated Schwarz map through the Picard-Vessiot Theory.

The Origin of Mercury's Surface Composition, an Experimental Investigation

NASA Technical Reports Server (NTRS)

Boujibar, A.; Righter, K.; Rapp, J. F.; Ross, D. K.; Pando, K. M.; Danielson, L. R.; Fontaine, E.

2016-01-01

Introduction: Results from MESSENGER spacecraft have confirmed the reduced nature of Mercury, based on its high core/mantle ratio and its FeO-poor and S-rich surface. Moreover, high resolution images revealed large volcanic plains and abundant pyroclastic deposits, suggesting major melting stages of the Mercurian mantle. In addition, MESSENGER has provided the most precise data to date on major elemental compositions of Mercury's surface. These results revealed considerable chemical heterogeneities that suggested several stages of differentiation and re-melting processes. This interpretation was challenged by our experimental previous study, which showed a similar compositional variation in the melting products of enstatite chondrites, which are a possible Mercury analogue. However, these experimental melts were obtained over a limited range of pressure (1 bar to 1 gigapascal) and were not compared to the most recent elemental maps. Therefore, here we extend the experimental dataset to higher pressures and perform a more quantitative comparison with Mercury's surface compositions measured by MESSENGER. In particular, we test whether these chemical heterogeneities result from mixing between polybaric melts. Our experiments and models show that the majority of chemical diversity of Mercury's surface can result from melting of a primitive mantle compositionally similar to enstatite chondrites in composition at various depths and degrees of melting. The high-Mg region's composition is reproduced by melting at high pressure (3 gigapascals) (Tab. 1), which is consistent with previous interpretation as being a large degraded impact basin based on its low elevation and thin average crust. While low-Mg NVP (North Volcanic Plains) are the result of melting at low pressure (1 bar), intermediate-Mg NVP, Caloris Basin and Rachmaninoff result from mixing of a high-pressure (3 gigapascals) and low-pressure components (1 bar for Rachmaninoff and 1 gigapascal for the other regions) (Tab. 1). Moreover, all compositions suggest mixing between low and high degree melts that indicate important differentiation processes.

Long-Term Dynamics of Autonomous Fractional Differential Equations

NASA Astrophysics Data System (ADS)

Liu, Tao; Xu, Wei; Xu, Yong; Han, Qun

This paper aims to investigate long-term dynamic behaviors of autonomous fractional differential equations with effective numerical method. The long-term dynamic behaviors predict where systems are heading after long-term evolution. We make some modification and transplant cell mapping methods to autonomous fractional differential equations. The mapping time duration of cell mapping is enlarged to deal with the long memory effect. Three illustrative examples, i.e. fractional Lotka-Volterra equation, fractional van der Pol oscillator and fractional Duffing equation, are studied with our revised generalized cell mapping method. We obtain long-term dynamics, such as attractors, basins of attraction, and saddles. Compared with some existing stability and numerical results, the validity of our method is verified. Furthermore, we find that the fractional order has its effect on the long-term dynamics of autonomous fractional differential equations.

Formal Integrals and Noether Operators of Nonlinear Hyperbolic Partial Differential Systems Admitting a Rich Set of Symmetries

NASA Astrophysics Data System (ADS)

Startsev, Sergey Ya.

2017-05-01

The paper is devoted to hyperbolic (generally speaking, non-Lagrangian and nonlinear) partial differential systems possessing a full set of differential operators that map any function of one independent variable into a symmetry of the corresponding system. We demonstrate that a system has the above property if and only if this system admits a full set of formal integrals (i.e., differential operators which map symmetries into integrals of the system). As a consequence, such systems possess both direct and inverse Noether operators (in the terminology of a work by B. Fuchssteiner and A.S. Fokas who have used these terms for operators that map cosymmetries into symmetries and perform transformations in the opposite direction). Systems admitting Noether operators are not exhausted by Euler-Lagrange systems and the systems with formal integrals. In particular, a hyperbolic system admits an inverse Noether operator if a differential substitution maps this system into a system possessing an inverse Noether operator.

Changes in arterial blood pressure elicited by severe passive heating at rest is associated with hyperthermia-induced hyperventilation in humans.

PubMed

Fujii, Naoto; Ichinose, Masashi; Honda, Yasushi; Tsuji, Bun; Watanabe, Kazuhito; Kondo, Narihiko; Nishiyasu, Takeshi

2013-01-01

The arterial blood pressure and ventilatory responses to severe passive heating at rest varies greatly among individuals. We tested the hypothesis that the increase in ventilation seen during severe passive heating of resting humans is associated with a decrease in arterial blood pressure. Passive heating was performed on 18 healthy males using hot water immersion to the level of the iliac crest and a water-perfused suit. We then divided the subjects into two groups: MAP(NOTINC) (n = 8), whose mean arterial blood pressure (MAP) at the end of heating had increased by ≤3 mmHg, and MAP(INC) (n = 10), whose MAP increased by >3 mmHg. Increases in esophageal temperature (T (es)) elicited by the heating were similar in the two groups (+2.3 ± 0.3 vs. +2.4 ± 0.4 °C). Early during heating (increase in T (es) was <1.5 °C), MAP, minute ventilation ([Formula: see text]), and end-tidal CO(2) pressure ([Formula: see text]) were similar between the groups. However, during the latter part of heating (increase in T (es) was ≥1.5 °C), the increase in [Formula: see text] and decrease in [Formula: see text] were significantly greater or tended to be greater, while the increase in MAP was significantly smaller in MAP(NOTINC) than MAP(INC). Among all subjects, heating-induced changes in [Formula: see text] significantly and negatively correlated with heating-induced changes in MAP during the latter part of heating (r = -0.52 to -0.74, P < 0.05). These results suggest that, in resting humans, 25-50 % of the variation in the magnitude of the arterial blood pressure response to severe passive heating can be explained by the magnitude of hyperthermia-induced hyperventilation.

Exponential Thurston maps and limits of quadratic differentials

NASA Astrophysics Data System (ADS)

Hubbard, John; Schleicher, Dierk; Shishikura, Mitsuhiro

2009-01-01

We give a topological characterization of postsingularly finite topological exponential maps, i.e., universal covers g\\colon{C}to{C}setminus\\{0\\} such that 0 has a finite orbit. Such a map either is Thurston equivalent to a unique holomorphic exponential map λ e^z or it has a topological obstruction called a degenerate Levy cycle. This is the first analog of Thurston's topological characterization theorem of rational maps, as published by Douady and Hubbard, for the case of infinite degree. One main tool is a theorem about the distribution of mass of an integrable quadratic differential with a given number of poles, providing an almost compact space of models for the entire mass of quadratic differentials. This theorem is given for arbitrary Riemann surfaces of finite type in a uniform way.

Advanced methods for preparation and characterization of infrared detector materials. [crystallization and phase diagrams of Hg sub 1-x Cd sub x Te

NASA Technical Reports Server (NTRS)

Lehoczy, S. L.

1979-01-01

Crystal growth of Hg sub 1-x Cd sub x Te and density measurements of ingot slices are discussed. Radial compositional variations are evaluated from the results of infrared transmission edge mapping. The pseudo-binary HgTe-CdTe phase diagram is examined with reference to differential thermal analysis measurements. The phase equilibria calculations, based on the 'regular association solution' theory (R.A.S.) are explained and, using the obtained R.A.S. parameters, the activities of Hg, Cd, and Te vapors and their partial pressures over the pseudo-binary melt are calculated.

Differential pressure distribution measurement for the development of insect-sized wings

NASA Astrophysics Data System (ADS)

Takahashi, Hidetoshi; Matsumoto, Kiyoshi; Shimoyama, Isao

2013-05-01

This paper reports on the measurement of the differential pressure distribution over a flat, thin wing using a micro-electro-mechanical systems sensor. Sensors featuring a piezoresistive cantilever were attached to a polyimide/Cu wing. Because the weight of the cantilever element was less than 10 ng, the sensor can measure the differential pressure without interference from inertial forces, such as wing flapping motions. The dimensions of the sensor chips and the wing were 1.0 mm × 1.0 mm × 0.3 mm and 100 mm × 30 mm × 1 mm, respectively. The differential pressure distribution along the wing's chord direction was measured in a wind tunnel at an air velocity of 4.0 m s­-1 by changing the angle of attack. It was confirmed that the pressure coefficient calculated by the measured differential pressure distribution was similar to the value measured by a load cell.

The investigation of parachute fabric permeability under an unsteady pressure differential

NASA Astrophysics Data System (ADS)

Rondeau, Nichole C.

An apparatus for assessing permeability of textiles subjected to time-varying pressure differentials is presented. A Computer Numerically Controlled Piston Permeability Apparatus (CNC-PPA) that can control the volume flow rate through a fabric has been designed and built. This test device has been developed in an effort to improve the understanding and design choices for aerodynamic decelerators. Preliminary results for a low permeability fabric (PIA-C-44378, Type IV) under both steady and unsteady loads are presented. The results from this investigation do indicate a small effect of unsteady pressure differential on the fabric permeability. The fabric permeability is slightly higher than the static permeability when the pressure differential is increasing with respect to time and the opposite is true when the pressure differential is decreasing. This change in permeability is more pronounced as the pressure is higher and the pressure changes more rapidly with respect to time, suggesting dynamic permeability likely affects highly unsteady phenomena such as parachute opening.

Differences in Clinical Features of Methamphetamine Users with Persistent Psychosis and Patients with Schizophrenia.

PubMed

Wang, Liang-Jen; Lin, Shih-Ku; Chen, Yi-Chih; Huang, Ming-Chyi; Chen, Tzu-Ting; Ree, Shao-Chun; Chen, Chih-Ken

Methamphetamine exerts neurotoxic effects and elicits psychotic symptoms. This study attempted to compare clinical differences between methamphetamine users with persistent psychosis (MAP) and patients with schizophrenia. In addition, we examined the discrimination validity by using symptom clusters to differentiate between MAP and schizophrenia. We enrolled 53 MAP patients and 53 patients with schizophrenia. The psychopathology of participants was assessed using the Chinese version of the Diagnostic Interview for Genetic Studies and the 18-item Brief Psychiatric Rating Scale. Logistic regression was used to examine the predicted probability scores of different symptom combinations on discriminating between MAP and schizophrenia. The receiver operating characteristic (ROC) analyses and area under the curve (AUC) were further applied to examine the discrimination validity of the predicted probability scores on differentiating between MAP and schizophrenia. We found that MAP and schizophrenia demonstrated similar patterns of delusions. Compared to patients with schizophrenia, MAP experienced significantly higher proportions of visual hallucinations and of somatic or tactile hallucinations. However, MAP exhibited significantly lower severity in conceptual disorganization, mannerism/posturing, blunted affect, emotional withdrawal, and motor retardation compared to patients with schizophrenia. The ROC analysis showed that a predicted probability score combining the aforementioned 7 items of symptoms could significantly differentiate between MAP and schizophrenia (AUC = 0.77). Findings in the current study suggest that nuanced differences might exist in the clinical presentation of secondary psychosis (MAP) and primary psychosis (schizophrenia). Combining the symptoms as a whole may help with differential diagnosis for MAP and schizophrenia. © 2016 S. Karger AG, Basel.

Reliability of Pressure Ulcer Rates: How Precisely Can We Differentiate Among Hospital Units, and Does the Standard Signal‐Noise Reliability Measure Reflect This Precision?

PubMed Central

Cramer, Emily

2016-01-01

Abstract Hospital performance reports often include rankings of unit pressure ulcer rates. Differentiating among units on the basis of quality requires reliable measurement. Our objectives were to describe and apply methods for assessing reliability of hospital‐acquired pressure ulcer rates and evaluate a standard signal‐noise reliability measure as an indicator of precision of differentiation among units. Quarterly pressure ulcer data from 8,199 critical care, step‐down, medical, surgical, and medical‐surgical nursing units from 1,299 US hospitals were analyzed. Using beta‐binomial models, we estimated between‐unit variability (signal) and within‐unit variability (noise) in annual unit pressure ulcer rates. Signal‐noise reliability was computed as the ratio of between‐unit variability to the total of between‐ and within‐unit variability. To assess precision of differentiation among units based on ranked pressure ulcer rates, we simulated data to estimate the probabilities of a unit's observed pressure ulcer rate rank in a given sample falling within five and ten percentiles of its true rank, and the probabilities of units with ulcer rates in the highest quartile and highest decile being identified as such. We assessed the signal‐noise measure as an indicator of differentiation precision by computing its correlations with these probabilities. Pressure ulcer rates based on a single year of quarterly or weekly prevalence surveys were too susceptible to noise to allow for precise differentiation among units, and signal‐noise reliability was a poor indicator of precision of differentiation. To ensure precise differentiation on the basis of true differences, alternative methods of assessing reliability should be applied to measures purported to differentiate among providers or units based on quality. © 2016 The Authors. Research in Nursing & Health published by Wiley Periodicals, Inc. PMID:27223598

Measurement of the differential pressure of liquid metals

DOEpatents

Metz, H.J.

1975-09-01

This patent relates to an improved means for measuring the differential pressure between any two points in a process liquid metal coolant loop, wherein the flow of liquid metal in a pipe is opposed by a permanent magnet liquid metal pump until there is almost zero flow shown by a magnetic type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of high-temperature bellows or diaphragm seals, and a permanent magnet liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed. (auth)

Coupling between arterial pressure, cerebral blood velocity, and cerebral tissue oxygenation with spontaneous and forced oscillations.

PubMed

Rickards, Caroline A; Sprick, Justin D; Colby, Hannah B; Kay, Victoria L; Tzeng, Yu-Chieh

2015-04-01

We tested the hypothesis that transmission of arterial pressure to brain tissue oxygenation is low under conditions of arterial pressure instability. Two experimental models of hemodynamic instability were used in healthy human volunteers; (1) oscillatory lower body negative pressure (OLBNP) (N = 8; 5 male, 3 female), and; (2) maximal LBNP to presyncope (N = 21; 13 male, 8 female). Mean arterial pressure (MAP), middle cerebral artery velocity (MCAv), and cerebral tissue oxygen saturation (ScO2) were measured non-invasively. For the OLBNP protocol, between 0 and -60 mmHg negative pressure was applied for 20 cycles at 0.05 Hz, then 20 cycles at 0.1 Hz. For the maximal LBNP protocol, progressive 5 min stages of chamber decompression were applied until the onset of presyncope. Spectral power of MAP, mean MCAv, and ScO2 were calculated within the VLF (0.04-0.07 Hz), and LF (0.07-0.2 Hz) ranges, and cross-spectral coherence was calculated for MAP-mean MCAv, MAP-ScO2, and mean MCAv-ScO2 at baseline, during each OLBNP protocol, and at the level prior to pre-syncope during maximal LBNP (sub-max). The key findings are (1) both 0.1 Hz OLBNP and sub-max LBNP elicited increases in LF power for MAP, mean MCAv, and ScO2 (p ≤ 0.08); (2) 0.05 Hz OLBNP increased VLF power in MAP and ScO2 only (p ≤ 0.06); (3) coherence between MAP-mean MCAv was consistently higher (≥0.71) compared with MAP-ScO2, and mean MCAv-ScO2 (≤0.43) during both OLBNP protocols, and sub-max LBNP (p ≤ 0.04). These data indicate high linearity between pressure and cerebral blood flow variations, but reduced linearity between cerebral tissue oxygenation and both arterial pressure and cerebral blood flow. Measuring arterial pressure variability may not always provide adequate information about the downstream effects on cerebral tissue oxygenation, the key end-point of interest for neuronal viability.

Central command differentially affects aortic and carotid sinus baroreflexes at the onset of spontaneous motor activity.

PubMed

Matsukawa, Kanji; Ishii, Kei; Idesako, Mitsuhiro; Ishida, Tomoko; Endo, Kana; Liang, Nan

2013-12-01

Our laboratory has recently demonstrated that central command provides selective inhibition of the cardiomotor component of aortic (AOR) baroreflex during exercise, preserving carotid sinus (CS) baroreflex. To further explore the differential effects of central command on the arterial baroreflexes, we surgically separated the AOR and CS baroreflex systems, to identify the input-output relationship of each baroreflex system using brief occlusion of the abdominal aorta in decerebrate cats. Baroreflex sensitivity for heart rate (HR) was estimated from the baroreflex ratio between the pressor and bradycardia responses during aortic occlusion and from the slope of the baroreflex curve between the changes in mean arterial blood pressure (ΔMAP) and ΔHR. Spontaneous motor activity accompanied the abrupt increases in HR and MAP. When aortic occlusion was given at the onset of spontaneous motor activity, the baroreflex ratio was blunted to 11-25% of the preexercise value in either intact or AOR baroreflex. The slope of the ΔMAP-ΔHR curve was similarly attenuated at the onset of spontaneous motor activity to 11-18% of the slope during the preexercise period. In contrast, in the CS baroreflex, the baroreflex ratio and curve slope were not significantly (P>0.05) altered by spontaneous motor activity. An upward shift of the baroreflex curve appeared at the onset of spontaneous motor activity, irrespective of the intact, AOR, and CS baroreflex conditions. Taken together, it is concluded that central command provides selective inhibition for the cardiomotor limb of the aortic baroreflex at the onset of exercise, which in turn contributes to an instantaneous increase in HR. © 2013.

Spatial Characteristics of the Unsteady Differential Pressures on 16 percent F/A-18 Vertical Tails

NASA Technical Reports Server (NTRS)

Moses, Robert W.; Ashley, Holt

1998-01-01

Buffeting is an aeroelastic phenomenon which plagues high performance aircraft at high angles of attack. For the F/A-18 at high angles of attack, vortices emanating from wing/fuselage leading edge extensions burst, immersing the vertical tails in their turbulent wake. The resulting buffeting of the vertical tails is a concern from fatigue and inspection points of view. Previous flight and wind-tunnel investigations to determine the buffet loads on the tail did not provide a complete description of the spatial characteristics of the unsteady differential pressures. Consequently, the unsteady differential pressures were considered to be fully correlated in the analyses of buffet and buffeting. The use of fully correlated pressures in estimating the generalized aerodynamic forces for the analysis of buffeting yielded responses that exceeded those measured in flight and in the wind tunnel. To learn more about the spatial characteristics of the unsteady differential pressures, an available 16%, sting-mounted, F-18 wind-tunnel model was modified and tested in the Transonic Dynamics Tunnel (TDT) at the NASA Langley Research Center as part of the ACROBAT (Actively Controlled Response Of Buffet-Affected Tails) program. Surface pressures were measured at high angles of attack on flexible and rigid tails. Cross-correlation and cross-spectral analyses of the pressure time histories indicate that the unsteady differential pressures are not fully correlated. In fact, the unsteady differential pressure resemble a wave that travels along the tail. At constant angle of attack, the pressure correlation varies with flight speed.

The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. II. Differential-reddening Map

NASA Astrophysics Data System (ADS)

Bellini, A.; Anderson, J.; van der Marel, R. P.; King, I. R.; Piotto, G.; Bedin, L. R.

2017-06-01

We take advantage of the exquisite quality of the Hubble Space Telescope astro-photometric catalog of the core of ωCen presented in the first paper of this series to derive a high-resolution, high-precision, high-accuracy differential-reddening map of the field. The map has a spatial resolution of 2 × 2 arcsec2 over a total field of view of about 4.‧3 × 4.‧3. The differential reddening itself is estimated via an iterative procedure using five distinct color-magnitude diagrams, which provided consistent results to within the 0.1% level. Assuming an average reddening value E(B - V) = 0.12, the differential reddening within the cluster’s core can vary by up to ±10%, with a typical standard deviation of about 4%. Our differential-reddening map is made available to the astronomical community in the form of a multi-extension FITS file. This differential-reddening map is essential for a detailed understanding of the multiple stellar populations of ωCen, as presented in the next paper in this series. Moreover, it provides unique insight into the level of small spatial-scale extinction variations in the Galactic foreground. Based on archival observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

The effect of hydrostatic pressure on staurosporine-induced neural differentiation in mouse bone marrow‑derived mesenchymal stem cells.

PubMed

Javanmard, F; Azadbakht, M; Pourmoradi, M

2016-01-01

In this study, the role of hydrostatic pressure on staurosporine-induced neural differentiation in mouse bone marrow mesenchymal stem cells were investigated. The cells were cultured in treatment medium containing 100 nM of staurosporine for 4 hours; then the cells were affected by hydrostatic pressure (0, 25,50, 100 mmHg). The percentage of cell viability by trypan blue staining and the percentage of cell death by Hoechst/PI differential staining were assessed. We obtained the total neurite length. Expression of β-tubulin III and GFAP (Glial fibrillary acidic protein) proteins were also analyzed by immunocytochemistry. The percentage of cell viability in treatments decreased relative to the increase in hydrostatic pressure and time (p Keywords: bone marrow mesenchymal stem cell, hydrostatic pressure, immunocytochemistry, neural differentiation, neurite length, cell differentiation.

Balloon-Supported Loran Antenna, New Hardware for Tethered Balloons, and Payloads Used in BAMM Flights.

DTIC Science & Technology

1980-02-28

containing a command receiver, batteries, and a differential- pressure switch , all located immediately below the confluence point, with long leads and a...should break free, or during normal deflation at take- down. Purpose of the differential- pressure switch was to momentarily open the valves if the...otherwise was completely different. A differential- pressure switch of the type formerly used in the command package, but without the long pressure

Regulation of choroidal blood flow during combined changes in intraocular pressure and arterial blood pressure.

PubMed

Polska, Elzbieta; Simader, Christian; Weigert, Günter; Doelemeyer, Arno; Kolodjaschna, Julia; Scharmann, Ole; Schmetterer, Leopold

2007-08-01

To test the hypothesis that human choroidal blood flow (ChBF) may depend, not only on ocular perfusion pressure (OPP), but also on absolute mean arterial pressure (MAP) and intraocular pressure (IOP). There were two study days in an open design. On the first day, OPP was varied by elevating IOP during a squatting-induced increase in MAP (28 subjects). On the second day, only the IOP was increased (17 subjects). IOP was raised in stepwise increments by using the suction cup Subfoveal ChBF (laser Doppler flowmetry), MAP, and IOP were assessed, and OPP was calculated as (2/3)(MAP - IOP). For correlation analysis, data from all subjects were pooled according to IOP and MAP, and correlation analyses were performed. When data from study day 1 were grouped according to IOP, no correlation was observed between ChBF and MAP; but ChBFs were lower, the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001), but correlations were independent of MAP. When data of study day 2 were pooled according to IOP, a correlation between ChBF and OPP was seen only at IOP > 40 mm Hg (P < 0.05). The data confirm previously published observations that the choroid shows some autoregulatory capacity during changes in OPP. In addition, the data indicate that the choroid regulates its blood flow better during exercise-induced changes in MAP than during an experimental increase in IOP.

Active recovery attenuates the fall in sweat rate but not cutaneous vascular conductance after supine exercise.

PubMed

Wilson, Thad E; Carter, Robert; Cutler, Michael J; Cui, Jian; Smith, Michael L; Crandall, Craig G

2004-02-01

The purpose of this study was to identify whether baroreceptor unloading was responsible for less efficient heat loss responses (i.e., skin blood flow and sweat rate) previously reported during inactive compared with active recovery after upright cycle exercise (Carter R III, Wilson TE, Watenpaugh DE, Smith ML, and Crandall CG. J Appl Physiol 93: 1918-1929, 2002). Eight healthy adults performed two 15-min bouts of supine cycle exercise followed by inactive or active (no-load pedaling) supine recovery. Core temperature (T(core)), mean skin temperature (T(sk)), heart rate, mean arterial blood pressure (MAP), thoracic impedance, central venous pressure (n = 4), cutaneous vascular conductance (CVC; laser-Doppler flux/MAP expressed as percentage of maximal vasodilation), and sweat rate were measured throughout exercise and during 5 min of recovery. Exercise bouts were similar in power output, heart rate, T(core), and T(sk). Baroreceptor loading and thermal status were similar during trials because MAP (90 +/- 4, 88 +/- 4 mmHg), thoracic impedance (29 +/- 1, 28 +/- 2 Omega), central venous pressure (5 +/- 1, 4 +/- 1 mmHg), T(core) (37.5 +/- 0.1, 37.5 +/- 0.1 degrees C), and T(sk) (34.1 +/- 0.3, 34.2 +/- 0.2 degrees C) were not significantly different at 3 min of recovery between active and inactive recoveries, respectively; all P > 0.05. At 3 min of recovery, chest CVC was not significantly different between active (25 +/- 6% of maximum) and inactive (28 +/- 6% of maximum; P > 0.05) recovery. In contrast, at this time point, chest sweat rate was higher during active (0.45 +/- 0.16 mg.cm(-2).min(-1)) compared with inactive (0.34 +/- 0.19 mg.cm(-2).min(-1); P < 0.05) recovery. After exercise CVC and sweat rate are differentially controlled, with CVC being primarily influenced by baroreceptor loading status while sweat rate is influenced by other factors.

Regional maps of subsurface geopressure gradients of the onshore and offshore Gulf of Mexico basin

USGS Publications Warehouse

Burke, Lauri A.; Kinney, Scott A.; Dubiel, Russell F.; Pitman, Janet K.

2013-01-01

The U.S. Geological Survey created a comprehensive geopressure-gradient model of the regional pressure system spanning the onshore and offshore Gulf of Mexico basin, USA. This model was used to generate ten maps that included (1) five contour maps characterizing the depth to the surface defined by the first occurrence of isopressure gradients ranging from 0.60 psi/ft to 1.00 psi/ft, in 0.10-psi/ft increments; and (2) five supporting maps illustrating the spatial density of the data used to construct the contour maps. These contour maps of isopressure-gradients at various increments enable the identification and quantification of the occurrence, magnitude, location, and depth of the subsurface pressure system, which allows for the broad characterization of regions exhibiting overpressured, underpressured, and normally pressured strata. Identification of overpressured regions is critical for exploration and evaluation of potential undiscovered hydrocarbon accumulations based on petroleum-generation pressure signatures and pressure-retention properties of reservoir seals. Characterization of normally pressured regions is essential for field development decisions such as determining the dominant production drive mechanisms, evaluating well placement and drainage patterns, and deciding on well stimulation methods such as hydraulic fracturing. Identification of underpressured regions is essential for evaluating the feasibility of geological sequestration and long-term containment of fluids such as supercritical carbon dioxide for alternative disposal methods of greenhouse gases. This study is the first, quantitative investigation of the regional pressure systems of one of the most important petroleum provinces in the United States. Although this methodology was developed for pressure studies in the Gulf of Mexico basin, it is applicable to any basin worldwide.

Differential Epitope Mapping by STD NMR Spectroscopy To Reveal the Nature of Protein-Ligand Contacts.

PubMed

Monaco, Serena; Tailford, Louise E; Juge, Nathalie; Angulo, Jesus

2017-11-27

Saturation transfer difference (STD) NMR spectroscopy is extensively used to obtain epitope maps of ligands binding to protein receptors, thereby revealing structural details of the interaction, which is key to direct lead optimization efforts in drug discovery. However, it does not give information about the nature of the amino acids surrounding the ligand in the binding pocket. Herein, we report the development of the novel method differential epitope mapping by STD NMR (DEEP-STD NMR) for identifying the type of protein residues contacting the ligand. The method produces differential epitope maps through 1) differential frequency STD NMR and/or 2) differential solvent (D 2 O/H 2 O) STD NMR experiments. The two approaches provide different complementary information on the binding pocket. We demonstrate that DEEP-STD NMR can be used to readily obtain pharmacophore information on the protein. Furthermore, if the 3D structure of the protein is known, this information also helps in orienting the ligand in the binding pocket. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Preliminary Engineering Design Package for the Basin A Neck Groundwater Intercept and Treatment System Interim Response Action

DTIC Science & Technology

1989-02-01

INDICATOR pPOST-FILTERED VITER RPUESIC POST-FILTRATION POLYMER SOLUTION MCUUM BREAKER FILTRATION POLYMER D*+RENTALkL PRESSURE SWITCH FEED PUMPS POLYMER...differential pressure switch signals the need for backwash of the operating filter. At this time, flow is S automatically switched to the standby filter...filter is undergoing backwash or on standby. High differential pressure across the filter bed, as sensed by a differential pressure switch , signals

Elastic properties of overpressured and unconsolidated sediments

USGS Publications Warehouse

Lee, Myung W.

2003-01-01

Differential pressure affects elastic velocities and Poisson?s ratio of sediments in such a way that velocities increase as differential pressure increases. Overpressured zones in sediments can be detected by observing an increase in Poisson?s ratio with a corresponding drop in elastic velocities. In highly overpressured sands, such as shallow water flow sands, the P-to S-wave velocity ratio (Vp/Vs) is very high, on the order of 10 or higher, due to the unconsolidated and uncemented nature of sediments. In order to predict elastic characteristics of highly overpressured sands, Biot-Gassmann theory by Lee (BGTL) is used with a variable exponent n that depends on differential pressure and the degree of consolidation/compaction. The exponent n decreases as differential pressure and the degree of consolidation increases, and, as n decreases, velocity increases and Vp/Vs decreases. The predicted velocity ratio by BGTL agrees well with the measured velocity ratio at low differential pressure for unconsolidated sediments.

Static magnetic field blood pressure buffering, baroreflex vs. vascular blood pressure control mechanism.

PubMed

Gmitrov, Juraj

2010-02-01

We compared the effect of static magnetic field (SMF) and verapamil, a potent vascular calcium channel blocking agent, on sudden elevation in blood pressure in conjunction with arterial baroreflex sensitivity (BRS) and microcirculation. Forty-four experiments were performed on conscious rabbits sedated using pentobarbital intravenous (i.v.) infusion (5 mg kg(-1) h(-1)). Mean femoral artery blood pressure (MAP), heart rate, BRS and ear lobe skin microcirculatory blood flow, estimated using microphotoelectric plethysmography (MPPG), were simultaneously measured after a 40 min exposure of the sinocarotid baroreceptors to 350 mT SMF, generated by Nd(2)-Fe(14)-B magnets, or 30 min of verapamil i.v. administration (20 microg kg(-1) min(-1)). BRS was assessed from heart rate and MAP responses to i.v. bolus of nitroprusside and phenylephrine. The decrease in phenylephrine-induced abrupt elevation in MAP (DeltaMAP(AE)) was significantly larger after verapamil than after SMF exposure. DeltaMAP(AE) inversely correlated with verapamil-induced significant increase in DeltaMPPG (r = 0.53, p < 0.000) and with SMF-induced significant increase in DeltaBRS (r = 0.47, p < 0.016). Our results suggest that verapamil-potentiated vascular blood pressure buffering mechanism was more effective than SMF-potentiated baroreflex-mediated blood pressure buffering mechanism, and a potential benefit of both approaches in cardiovascular conditions with abrupt high elevation in blood pressure.

Surface pressure maps from scatterometer data

NASA Technical Reports Server (NTRS)

Brown, R. A.; Levy, Gad

1991-01-01

The ability to determine surface pressure fields from satellite scatterometer data was shown by Brown and Levy (1986). The surface winds are used to calculate the gradient winds above the planetary boundary layer, and these are directly related to the pressure gradients. There are corrections for variable stratification, variable surface roughness, horizontal inhomogeneity, humidity and baroclinity. The Seasat-A Satellite Scatterometer (SASS) data have been used in a systematic study of 50 synoptic weather events (regions of approximately 1000 X 1000 km). The preliminary statistics of agreement with national weather service surface pressure maps are calculated. The resulting surface pressure maps can be used together with SASS winds and Scanning Multichannel Microwave Radiometer (SMMR) water vapor and liquid water analyses to provide good front and storm system analyses.

Sequential compression device with thigh-high sleeves supports mean arterial pressure during Caesarean section under spinal anaesthesia.

PubMed

Adsumelli, R S N; Steinberg, E S; Schabel, J E; Saunders, T A; Poppers, P J

2003-11-01

This study investigated the use of a Sequential Compression Device (SCD) with thigh-high sleeves and a preset pressure of 50 mm Hg that recruits blood from the lower limbs intermittently, as a method to prevent spinal hypotension during elective Caesarean section. Possible association of arterial pressure changes with maternal, fetal, haemodynamic, and anaesthetic factors were studied. Fifty healthy parturients undergoing elective Caesarean section under spinal anaesthesia were randomly assigned to either SCD (n=25) or control (n=25) groups. A standardized protocol for pre-hydration and anaesthetic technique was followed. Hypotension was defined as a decrease in any mean arterial pressure (MAP) measurement by more than 20% of the baseline MAP. Systolic (SAP), MAP and diastolic (DAP) arterial pressure, pulse pressure (PP), and heart rate (HR) were noted at baseline and every minute after the spinal block until delivery. A greater than 20% decrease in MAP occurred in 52% of patients in the SCD group vs 92% in the control group (P=0.004, odds ratio 0.094, 95% CI 0.018-0.488). There were no significant differences in SAP, DAP, HR, and PP between the groups. SCD use in conjunction with vasopressor significantly reduced the incidence of a 20% reduction of MAP.

Bifurcation and chaos of a new discrete fractional-order logistic map

NASA Astrophysics Data System (ADS)

Ji, YuanDong; Lai, Li; Zhong, SuChuan; Zhang, Lu

2018-04-01

The fractional-order discrete maps with chaotic behaviors based on the theory of ;fractional difference; are proposed in recent years. In this paper, instead of using fractional difference, a new fractionalized logistic map is proposed based on the numerical algorithm of fractional differentiation definition. The bifurcation diagrams of this map with various differential orders are given by numerical simulation. The simulation results show that the fractional-order logistic map derived in this manner holds rich dynamical behaviors because of its memory effect. In addition, new types of behaviors of bifurcation and chaos are found, which are different from those of the integer-order and the previous fractional-order logistic maps.

Reliability of Pressure Ulcer Rates: How Precisely Can We Differentiate Among Hospital Units, and Does the Standard Signal-Noise Reliability Measure Reflect This Precision?

PubMed

Staggs, Vincent S; Cramer, Emily

2016-08-01

Hospital performance reports often include rankings of unit pressure ulcer rates. Differentiating among units on the basis of quality requires reliable measurement. Our objectives were to describe and apply methods for assessing reliability of hospital-acquired pressure ulcer rates and evaluate a standard signal-noise reliability measure as an indicator of precision of differentiation among units. Quarterly pressure ulcer data from 8,199 critical care, step-down, medical, surgical, and medical-surgical nursing units from 1,299 US hospitals were analyzed. Using beta-binomial models, we estimated between-unit variability (signal) and within-unit variability (noise) in annual unit pressure ulcer rates. Signal-noise reliability was computed as the ratio of between-unit variability to the total of between- and within-unit variability. To assess precision of differentiation among units based on ranked pressure ulcer rates, we simulated data to estimate the probabilities of a unit's observed pressure ulcer rate rank in a given sample falling within five and ten percentiles of its true rank, and the probabilities of units with ulcer rates in the highest quartile and highest decile being identified as such. We assessed the signal-noise measure as an indicator of differentiation precision by computing its correlations with these probabilities. Pressure ulcer rates based on a single year of quarterly or weekly prevalence surveys were too susceptible to noise to allow for precise differentiation among units, and signal-noise reliability was a poor indicator of precision of differentiation. To ensure precise differentiation on the basis of true differences, alternative methods of assessing reliability should be applied to measures purported to differentiate among providers or units based on quality. © 2016 The Authors. Research in Nursing & Health published by Wiley Periodicals, Inc. © 2016 The Authors. Research in Nursing & Health published by Wiley Periodicals, Inc.

Invasive blood pressure recording comparing nursing charts with an electronic monitor: a technical report.

PubMed

Wong, Benjamin T; Glassford, Neil J; Bion, Victoria; Chai, Syn Y; Bellomo, Rinaldo

2014-03-01

Blood pressure management (assessed using nursing charts) in the early phase of septic shock may have an effect on renal outcomes. Assessment of mean arterial pressure (MAP) values as recorded on nursing charts may be inaccurate. To determine the difference between hourly blood pressure values as recorded on the nursing charts and hourly average blood pressure values over the corresponding period obtained electronically from the bedside monitor. We studied 20 patients with shock requiring vasopressor support and invasive blood pressure monitoring. Hourly blood pressure measurements were recorded on the nursing charts over a 12-hour period. Blood pressure values recorded every 10 minutes were downloaded from electronic patient monitors over the corresponding period. The hourly average of the 10-minute blood pressure values was compared with the measurements recorded on the nursing charts. We assessed 240 chart readings and 1440 electronic recordings. Average chart MAP was 72.54 mmHg and average electronic monitor MAP was 71.54 mmHg. MAP data from the two sources showed a strong correlation (ρ0.71, P < 0.005). Bland-Altman assessment revealed acceptable agreement, with a mean bias of 1mmHg and 95% limits of agreement of -11.76 mmHg and 13.76 mmHg. Using average data over 6 hours, 95% limits of agreement narrowed to -6.79mmHg and 8.79mmHg. With multiple measurements over time, mean blood pressure as recorded on nursing charts reasonably approximates mean blood pressure recorded on the monitor.

Fuel cell system shutdown with anode pressure control

DOEpatents

Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

2002-01-01

A venting methodology and pressure sensing and vent valving arrangement for monitoring anode bypass valve operating during the normal shutdown of a fuel cell apparatus of the type used in vehicle propulsion systems. During a normal shutdown routine, the pressure differential between the anode inlet and anode outlet is monitored in real time in a period corresponding to the normal closing speed of the anode bypass valve and the pressure differential at the end of the closing cycle of the anode bypass valve is compared to the pressure differential at the beginning of the closing cycle. If the difference in pressure differential at the beginning and end of the anode bypass closing cycle indicates that the anode bypass valve has not properly closed, a system controller switches from a normal shutdown mode to a rapid shutdown mode in which the anode inlet is instantaneously vented by rapid vents.

Pulse Oximeter Derived Blood Pressure Measurement in Patients With a Continuous Flow Left Ventricular Assist Device.

PubMed

Hellman, Yaron; Malik, Adnan S; Lane, Kathleen A; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Munson, Sarah D; Pickrell, Jeanette; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

2017-05-01

Currently, blood pressure (BP) measurement is obtained noninvasively in patients with continuous flow left ventricular assist device (LVAD) by placing a Doppler probe over the brachial or radial artery with inflation and deflation of a manual BP cuff. We hypothesized that replacing the Doppler probe with a finger-based pulse oximeter can yield BP measurements similar to the Doppler derived mean arterial pressure (MAP). We conducted a prospective study consisting of patients with contemporary continuous flow LVADs. In a small pilot phase I inpatient study, we compared direct arterial line measurements with an automated blood pressure (ABP) cuff, Doppler and pulse oximeter derived MAP. Our main phase II study included LVAD outpatients with a comparison between Doppler, ABP, and pulse oximeter derived MAP. A total of five phase I and 36 phase II patients were recruited during February-June 2014. In phase I, the average MAP measured by pulse oximeter was closer to arterial line MAP rather than Doppler (P = 0.06) or ABP (P < 0.01). In phase II, pulse oximeter MAP (96.6 mm Hg) was significantly closer to Doppler MAP (96.5 mm Hg) when compared to ABP (82.1 mm Hg) (P = 0.0001). Pulse oximeter derived blood pressure measurement may be as reliable as Doppler in patients with continuous flow LVADs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

The heart, macrocirculation and microcirculation in hypertension: a unifying hypothesis.

PubMed

Struijker Boudier, Harry A J; Cohuet, Géraldine M S; Baumann, Marcus; Safar, Michel E

2003-06-01

Epidemiological studies in the past decade have stressed the importance of both pulse pressure and mean arterial pressure (MAP) as important risk factors in hypertension-related cardiovascular disease. Pulse pressure and MAP are determined by different segments of the cardiovascular system. Pulse pressure is the pulsatile component of the blood pressure curve. It is determined by left ventricular ejection, the cushioning capacity (compliance) of the large arteries, and the timing and intensity of wave reflections from the microcirculation. MAP is the steady component; it is determined by cardiac output and peripheral (micro)vascular resistance. To a large degree, the structural design of the heart and vascular tree determine the pulse pressure and MAP, in addition to the propagation of the pressure wave through the vasculature. Pressure and flow, in contrast, influence the composition and geometry of the heart and vasculature. Hypertensive disease is associated with important structural alterations of the heart, such as hypertrophy and fibrosis, and of the vasculature, such as large artery stiffening, small artery remodelling and microvascular rarefaction. Recent basic research has revealed some of the molecular pathways involved in the remodelling of the cardiovascular system under the influence of physical forces. For correct understanding of the pathophysiology of hypertensive disease, its risks for target-organ damage and its effective treatment, both the pulsatile and steady components of the blood pressure curve must be considered.

Real Time Ferrograph Development.

DTIC Science & Technology

1979-11-01

differential temperature of 65 0 C. Since opteo- electronic devices (photodiodes, photoresistors, etc.) have a maximum operating temperature around 85 0 C, it is...flow during the precipitation cycle. This regulator must keep the flow rate constant at any given temperature regardless of the differential pressure...across the sensing head. The pressure regulator achieved this by using the differential pressure across a fixed re;7trictor to move a bellows diaphragm

Fractional Order Spatiotemporal Chaos with Delay in Spatial Nonlinear Coupling

NASA Astrophysics Data System (ADS)

Zhang, Yingqian; Wang, Xingyuan; Liu, Liyan; Liu, Jia

We investigate the spatiotemporal dynamics with fractional order differential logistic map with delay under nonlinear chaotic maps for spatial coupling connections. Here, the coupling methods between lattices are the nonlinear chaotic map coupling of lattices. The fractional order differential logistic map with delay breaks the limits of the range of parameter μ ∈ [3.75, 4] in the classical logistic map for chaotic states. The Kolmogorov-Sinai entropy density and universality, and bifurcation diagrams are employed to investigate the chaotic behaviors of the proposed model in this paper. The proposed model can also be applied for cryptography, which is verified in a color image encryption scheme in this paper.

System for measuring multiphase flow using multiple pressure differentials

DOEpatents

Fincke, James R.

2003-01-01

An improved method and system for measuring a multi-phase flow in a pressure flow meter. An extended throat venturi is used and pressure of the multi-phase flow is measured at three or more positions in the venturi, which define two or more pressure differentials in the flow conduit. The differential pressures are then used to calculate the mass flow of the gas phase, the total mass flow, and the liquid phase. The system for determining the mass flow of the high void fraction fluid flow and the gas flow includes taking into account a pressure drop experienced by the gas phase due to work performed by the gas phase in accelerating the liquid phase.

Validation of Test Methods for Air Leak Rate Verification of Spaceflight Hardware

NASA Technical Reports Server (NTRS)

Oravec, Heather Ann; Daniels, Christopher C.; Mather, Janice L.

2017-01-01

As deep space exploration continues to be the goal of NASAs human spaceflight program, verification of the performance of spaceflight hardware becomes increasingly critical. Suitable test methods for verifying the leak rate of sealing systems are identified in program qualification testing requirements. One acceptable method for verifying the air leak rate of gas pressure seals is the tracer gas leak detector method. In this method, a tracer gas (commonly helium) leaks past the test seal and is transported to the leak detector where the leak rate is quantified. To predict the air leak rate, a conversion factor of helium-to-air is applied depending on the magnitude of the helium flow rate. The conversion factor is based on either the molecular mass ratio or the ratio of the dynamic viscosities. The current work was aimed at validating this approach for permeation-level leak rates using a series of tests with a silicone elastomer O-ring. An established pressure decay method with constant differential pressure was used to evaluate both the air and helium leak rates of the O-ring under similar temperature and pressure conditions. The results from the pressure decay tests showed, for the elastomer O-ring, that neither the molecular flow nor the viscous flow helium-to-air conversion factors were applicable. Leak rate tests were also performed using nitrogen and argon as the test gas. Molecular mass and viscosity based helium-to-test gas conversion factors were applied, but did not correctly predict the measured leak rates of either gas. To further this study, the effect of pressure boundary conditions was investigated. Often, pressure decay leak rate tests are performed at a differential pressure of 101.3 kPa with atmospheric pressure on the downstream side of the test seal. In space applications, the differential pressure is similar, but with vacuum as the downstream pressure. The same O-ring was tested at four unique differential pressures ranging from 34.5 to 137.9 kPa. Up to six combinations of upstream and downstream pressures for each differential pressure were compared. For a given differential pressure, the various combinations of upstream and downstream dry air pressures did not significantly affect the leak rate. As expected, the leak rate of the O-ring increased with increasing differential pressure. The results suggested that the current leak test pressure conditions, used to verify spacecraft sealing systems with elastomer seals, produce accurate values even though the boundary conditions do not model the space application.

Optimized surgical treatment for normal pressure hydrocephalus: comparison between gravitational and differential pressure valves.

PubMed

Suchorska, B; Kunz, M; Schniepp, R; Jahn, K; Goetz, C; Tonn, J C; Peraud, A

2015-04-01

In idiopathic normal pressure hydrocephalus (NPH) ventriculoperitoneal (VP) shunt insertion is the method of choice to improve cardinal symptoms such as gait disturbance, urge incontinence and/or dementia. With reduced compliance, the brain of the elderly is prone for overdrainage complications. This was especially true with the use of differential pressure valve implantation. The present study compares clinical outcome and complication rates after VP shunt insertion with differential pressure valves in the early years and gravitational valves since 2005. The authors reviewed patients treated at our institution for NPH since 1995. Differential pressure valves were solely used in the initial years, while the treatment regimen changed to gravitational valves in 2005. Clinical improvement/surgical success rates as well as complications were compared between the two groups. Eighty-nine patients were enrolled for the present study. Mean age at the time of surgery was 73.5 ± 6.3 years. Male patients predominated with 73, compared with 16 female patients. Median follow-up time was 28 ± 26 months. Date of last follow-up was 1st October 2013. Forty-nine patients received a gravitational valve, while 40 were treated with differential pressure valves. In the gravitational group a significant improvement was observed after shunt insertion for gait disorder, cognitive impairment and urge incontinence (p < 0.0001, resp. p = 0.004), while a significant change in the differential pressure group was only seen for gait disorder (p = 0.03) but not for cognition or urinary incontinency (p > 0.05). The risk of hygroma as a sign of shunt overdrainage requiring surgical intervention was significantly higher in the differential pressure group (5 versus 0 in the gravitational group). Patients with NPH treated with gravitational valves in the present cohort showed a more profound improvement in their initial symptoms, including gait disorder, cognitive impairment and urinary incontinency without the risk of overdrainage complications requiring surgical intervention when compared with patients who received differential pressure valves in previous years.

Tractor seating for operators with paraplegia.

PubMed

Wilhite, C S; Field, W E; Jaramillo, M

2017-01-01

This feasibility study explored the utility of using a pressure mapping instrument to explore the variable of pressure under subjects sitting on a commonly used tractor seat, and four other cushion interventions. The research model used single-subject with repeated measures during simulated tractor operation. In examining the graphical images and pressure mapping data available from the instrument; the contour tractor seat used in this study was not sufficient in redistributing pressure for people with paraplegia operating tractors, putting them at greater risk for acquiring a pressure ulcer. The use of pressure mapping equipment to study seated pressure within dynamic environments is achievable, and further studies need to be performed and replicated in simulated or in vivo environments. The data in this study suggest people with paraplegia operating agricultural equipment may not have acceptable pressure distribution using the manufacturer's installed seat and must rely on adding wheelchair cushions or other materials to the seat surface to create acceptable pressure distribution. However, doing so changes other aspects of the seating micro or macro climate that can also be problematic.

D-dimer, factor VIII and von Willebrand factor predict a non-dipping pattern of blood pressure in hypertensive patients.

PubMed

Agorasti, Athanasia; Trivellas, Theodoros; Mourvati, Efthimia; Papadopoulos, Vasilios; Tsatalas, Konstantinos; Vargemezis, Vasilios; Passadakis, Ploumis

2013-06-01

The aim of this study is to assess whether the haemostatic markers D-dimer, factor VIII (FVIII) and von Willebrand factor (VWF) are predictive of non-dipping status in treated hypertensive patients; so, as easy available laboratory data can predict non-dipping pattern and help with the selection of the patients whom circadian blood pressure should be re-examined. Forty treated hypertensive patients with essential hypertension were included in the study. Twenty-four-hour ambulatory blood pressure monitoring was performed in all patients. Daytime and nocturnal average systolic, diastolic and mean blood pressures were calculated. Patients were characterised as "non-dippers" on the basis of a less than 10 % decline in nocturnal blood pressure (BP); either systolic or diastolic or mean (MAP). D-dimer as marker of fibrinolytic function, FVIII activity and VWF antigen as marker of endothelial dysfunction were measured on plasma. The predictive efficiency was analysed by receiver operating characteristic (ROC) curves. Youden index was used for the estimation of the cut-off points and the associated values for sensitivity and 1-specificity. Plasma levels of D-dimer, FVIII and VWF were significantly higher in non-dippers as compared with dippers, irrespective of the classification used (BP index); all P < 0.05. The ROC curves indicated a good diagnostic efficiency for D-dimer (AUC(ROC) = 0.697, 0.715 and 0.774), FVIII (AUC(ROC) = 0.714, 0.692 and 0.755) and VWF (AUC(ROC) = 0.706, 0.740 and 0.708) in distinguishing non-dipping pattern (systolic, diastolic or mean) in the study population; all P < 0.05. Among the three haemostatic markers, D-dimer presents the most satisfactory sensitivity/1-specificity for the differentiation of non-dippers, with a cut-off point >168 ng/ml (sensitivity/1-specificity for systolic BP non-dippers of 0.789/0.381, for diastolic BP non-dippers 0.923/0.444 and for MAP non-dippers 0.875/0.375). In conclusion, D-dimer has a good predictive value for non-dipping pattern and the decision for the 24-h ambulatory blood pressure re-monitoring among dippers could rely on its values.

Artificial redirection of sensation from prosthetic fingers to the phantom hand map on transradial amputees: vibrotactile versus mechanotactile sensory feedback.

PubMed

Antfolk, Christian; D'Alonzo, Marco; Controzzi, Marco; Lundborg, Göran; Rosén, Birgitta; Sebelius, Fredrik; Cipriani, Christian

2013-01-01

This work assesses the ability of transradial amputees to discriminate multi-site tactile stimuli in sensory discrimination tasks. It compares different sensory feedback modalities using an artificial hand prosthesis in: 1) a modality matched paradigm where pressure recorded on the five fingertips of the hand was fed back as pressure stimulation on five target points on the residual limb; and 2) a modality mismatched paradigm where the pressures were transformed into mechanical vibrations and fed back. Eight transradial amputees took part in the study and were divided in two groups based on the integrity of their phantom map; group A had a complete phantom map on the residual limb whereas group B had an incomplete or nonexisting map. The ability in localizing stimuli was compared with that of 10 healthy subjects using the vibration feedback and 11 healthy subjects using the pressure feedback (in a previous study), on their forearms, in similar experiments. Results demonstrate that pressure stimulation surpassed vibrotactile stimulation in multi-site sensory feedback discrimination. Furthermore, we demonstrate that subjects with a detailed phantom map had the best discrimination performance and even surpassed healthy participants for both feedback paradigms whereas group B had the worst performance overall. Finally, we show that placement of feedback devices on a complete phantom map improves multi-site sensory feedback discrimination, independently of the feedback modality.

L02 RELIEF AND SHUTOFF VALVE, PRESSURE SENSITIVE CONTROLLER, AND DIFFERENTIAL PRESSURE SWITCH CHECKOUT AND ’END TO END’ CALIBRATION OF THE LOP MISSILE FUEL AND L02 PRESSURE METERS, COMPLEX 576-A,

DTIC Science & Technology

Differential Pressure Switch after the Missile is erected in the tower and connected to Launch Control Circuitry. In addition, a procedure for the ’end to end’ of the L02 and Fuel Tank Pressure Meters is provided. (Author)

New Hardware for Tethered Balloons,

DTIC Science & Technology

1980-01-01

package contained a differential- pressure switch , and a command receiver. Long wires extended up to the gas valves to actuate them, and a long tube was...similar in appear- ance to the former valve, but does contain batteries, an aneroid- operated switch, and a differential- pressure switch . Design is such...that either the aneroid-operated switch or the differential- pressure switch can be easily removed for checking Or setting in the laboratory. Likewise the

Phenylephrine-induced elevations in arterial blood pressure are attenuated in heat-stressed humans

NASA Technical Reports Server (NTRS)

Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

2002-01-01

To test the hypothesis that phenylephrine-induced elevations in blood pressure are attenuated in heat-stressed humans, blood pressure was elevated via steady-state infusion of three doses of phenylephrine HCl in 10 healthy subjects in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature by 0.5 degrees C, muscle sympathetic nerve activity (MSNA), heart rate, and cardiac output and decreased total peripheral vascular resistance (TPR; all P < 0.005) but did not change mean arterial blood pressure (MAP; P > 0.05). At the highest dose of phenylephrine, the increase in MAP and TPR from predrug baselines was significantly attenuated during the heat stress [DeltaMAP 8.4 +/- 1.2 mmHg; DeltaTPR 0.96 +/- 0.85 peripheral resistance units (PRU)] compared with normothermia (DeltaMAP 15.4 +/- 1.4 mmHg, DeltaTPR 7.13 +/- 1.18 PRU; all P < 0.001). The sensitivity of baroreflex control of MSNA and heart rate, expressed as the slope of the relationship between MSNA and diastolic blood pressure, as well as the slope of the relationship between heart rate and systolic blood pressure, respectively, was similar between thermal conditions (each P > 0.05). These data suggest that phenylephrine-induced elevations in MAP are attenuated in heat-stressed humans without affecting baroreflex control of MSNA or heart rate.

Period adding cascades: experiment and modeling in air bubbling.

PubMed

Pereira, Felipe Augusto Cardoso; Colli, Eduardo; Sartorelli, José Carlos

2012-03-01

Period adding cascades have been observed experimentally/numerically in the dynamics of neurons and pancreatic cells, lasers, electric circuits, chemical reactions, oceanic internal waves, and also in air bubbling. We show that the period adding cascades appearing in bubbling from a nozzle submerged in a viscous liquid can be reproduced by a simple model, based on some hydrodynamical principles, dealing with the time evolution of two variables, bubble position and pressure of the air chamber, through a system of differential equations with a rule of detachment based on force balance. The model further reduces to an iterating one-dimensional map giving the pressures at the detachments, where time between bubbles come out as an observable of the dynamics. The model has not only good agreement with experimental data, but is also able to predict the influence of the main parameters involved, like the length of the hose connecting the air supplier with the needle, the needle radius and the needle length.

Erectile Dysfunction Precedes Coronary Artery Endothelial Dysfunction in Rats Fed a High-Fat, High-Sucrose, Western Pattern Diet

PubMed Central

La Favor, Justin D.; Anderson, Ethan J.; Hickner, Robert C.; Wingard, Christopher J.

2016-01-01

Introduction It is suggested that erectile dysfunction (ED) may be an early risk factor for cardiovascular disease. Aim The goal of this study was to determine whether development of ED precedes the onset of coronary artery endothelial dysfunction in response to a Western diet (WD), thereby establishing whether the WD differentially impacts the endothelium in a time-dependent manner. Additionally, a goal was to determine if diet-induced ED is reversible with intracavernosal sepiapterin treatment. Methods Male Sprague-Dawley rats were fed a WD for 4, 8, or 12 weeks, or a control diet for 8 weeks. Erectile function was evaluated by measuring the mean arterial pressure (MAP) and intracavernosal pressure (ICP) in response to electrical field stimulation of the cavernosal nerve near the major pelvic ganglion, in the absence and presence of sepiapterin. Coronary artery endothelial function was evaluated ex vivo with cumulative doses of acetylcholine (ACh) applied to segments of the left anterior descending coronary artery preconstricted with serotonin. Main Outcome Measures Erectile function was assessed as the ICP response to electrical field stimulation (EFS), normalized to MAP. Coronary artery endothelial function was assessed as the effective concentration producing 50% of a maximal response (EC50) of the ACh response. Results The ICP/MAP response to EFS was significantly attenuated following both 8 and 12 weeks of the WD compared with the control diet (P < 0.05). Sepiapterin treatment augmented the ICP/MAP response in all WD groups (P < 0.05). The coronary artery EC50 of the ACh response was not different from control following 4 or 8 weeks but was significantly elevated following 12 weeks of the WD (P < 0.01). Conclusions These data suggest that erectile function is reduced prior to coronary artery endothelial function in response to the WD. Improvement of erectile function with sepiapterin in WD rats indicates that nitric oxide synthase uncoupling is a key mechanism in diet-induced ED. PMID:23170997

Selective loss of orientation column maps in visual cortex during brief elevation of intraocular pressure.

PubMed

Chen, Xin; Sun, Chao; Huang, Luoxiu; Shou, Tiande

2003-01-01

To compare the orientation column maps elicited by different spatial frequency gratings in cortical area 17 of cats before and during brief elevation of intraocular pressure (IOP). IOP was elevated by injecting saline into the anterior chamber of a cat's eye through a syringe needle. The IOP was elevated enough to cause a retinal perfusion pressure (arterial pressure minus IOP) of approximately 30 mm Hg during a brief elevation of IOP. The visual stimulus gratings were varied in spatial frequency, whereas other parameters were kept constant. The orientation column maps of the cortical area 17 were monocularly elicited by drifting gratings of different spatial frequencies and revealed by a brain intrinsic signal optical imaging system. These maps were compared before and during short-term elevation of IOP. The response amplitude of the orientation maps in area 17 decreased during a brief elevation of IOP. This decrease was dependent on the retinal perfusion pressure but not on the absolute IOP. The location of the most visible maps was spatial-frequency dependent. The blurring or loss of the pattern of the orientation maps was most severe when high-spatial-frequency gratings were used and appeared most significantly on the posterior part of the exposed cortex while IOP was elevated. However, the basic patterns of the maps remained unchanged. Changes in cortical signal were not due to changes in the optics of the eye with elevation of IOP. A stable normal IOP is essential for maintaining normal visual cortical functions. During a brief and high elevation of IOP, the cortical processing of high-spatial-frequency visual information was diminished because of a selectively functional decline of the retinogeniculocortical X pathway by a mechanism of retinal circulation origin.

Assessment of histological differentiation in gastric cancers using whole-volume histogram analysis of apparent diffusion coefficient maps.

PubMed

Zhang, Yujuan; Chen, Jun; Liu, Song; Shi, Hua; Guan, Wenxian; Ji, Changfeng; Guo, Tingting; Zheng, Huanhuan; Guan, Yue; Ge, Yun; He, Jian; Zhou, Zhengyang; Yang, Xiaofeng; Liu, Tian

2017-02-01

To investigate the efficacy of histogram analysis of the entire tumor volume in apparent diffusion coefficient (ADC) maps for differentiating between histological grades in gastric cancer. Seventy-eight patients with gastric cancer were enrolled in a retrospective 3.0T magnetic resonance imaging (MRI) study. ADC maps were obtained at two different b values (0 and 1000 sec/mm 2 ) for each patient. Tumors were delineated on each slice of the ADC maps, and a histogram for the entire tumor volume was subsequently generated. A series of histogram parameters (eg, skew and kurtosis) were calculated and correlated with the histological grade of the surgical specimen. The diagnostic performance of each parameter for distinguishing poorly from moderately well-differentiated gastric cancers was assessed by using the area under the receiver operating characteristic curve (AUC). There were significant differences in the 5 th , 10 th , 25 th , and 50 th percentiles, skew, and kurtosis between poorly and well-differentiated gastric cancers (P < 0.05). There were correlations between the degrees of differentiation and histogram parameters, including the 10 th percentile, skew, kurtosis, and max frequency; the correlation coefficients were 0.273, -0.361, -0.339, and -0.370, respectively. Among all the histogram parameters, the max frequency had the largest AUC value, which was 0.675. Histogram analysis of the ADC maps on the basis of the entire tumor volume can be useful in differentiating between histological grades for gastric cancer. 4 J. Magn. Reson. Imaging 2017;45:440-449. © 2016 International Society for Magnetic Resonance in Medicine.

Arg16Gly polymorphism of the beta2-adrenergic receptor is associated with differences in cardiovascular function at rest and during exercise in humans.

PubMed

Snyder, Eric M; Beck, Kenneth C; Dietz, Niki M; Eisenach, John H; Joyner, Michael J; Turner, Stephen T; Johnson, Bruce D

2006-02-15

In humans, subjects homozygous for arginine (ArgArg) at codon 16 of the beta2-adrenergic receptor (beta2AR) have been shown to have greater agonist-mediated desensitization than subjects homozygous for glycine (GlyGly). We sought to determine if this substitution differentially influenced cardiovascular function during short duration (9 min) low and high intensity exercise (40 and 75% of peak work). Healthy Caucasian ArgArg (n = 16), GlyGly (n = 31) and ArgGly (n = 17) subjects matched for age, sex and peak oxygen uptake were studied. There were no differences in adrenaline (ADR) at rest or with heavy exercise, but the ArgArg group had lower ADR with light exercise (P = 0.04). Resting heart rate (HR) was higher in ArgArg (P < 0.01), while cardiac output (Q), stroke volume (SV), and mean arterial pressure (MAP) were lower than the other groups (HR = 86+/-2, 78+/-2, 80+/-1 beats min(-1); Q = 5.7+/-0.81, 6.1+/-0.18, 6.7+/-0.22 l min(-1); SV = 68+/-3, 82+/-3, 89+/-4 ml beat(-1); MAP = 92+/-1, 103+/-2, 98+/-1 mmHg-- for ArgArg, ArgGly and GlyGly, respectively, means +/-s.e.m., P < 0.01), however, no differences were observed in systemic vascular resistance (SVR). With low intensity exercise and high intensity exercise the ArgArg group continued to have a lower , SV and MAP compared to the other groups (P < 0.05), with no differences observed in SVR. During recovery, the ArgArg subjects continued to have a lower MAP but there were no differences in HR, , or SVR. These data suggest that subjects homozygous for Arg at codon 16 of the beta2AR have reduced and MAP at rest that persist during exercise with no evidence for differential changes over the course of exercise despite large changes in catecholamines. This may suggest possible genotype-related differences in baseline receptor function or density which causes phenotypic differences at rest that are sustained during short-term exercise.

Pressure mapping to prevent pressure ulcers in a hospital setting: A pragmatic randomised controlled trial.

PubMed

Gunningberg, Lena; Sedin, Inga-Maj; Andersson, Sara; Pingel, Ronnie

2017-07-01

Pressure ulcers cause suffering to patients and costs to society. Reducing pressure at the interface between the patient's body and the support surface is a valid clinical intervention for reducing the risk of pressure ulcers. However, studies have shown that knowledge of how to reduce pressure and shear and to prevent pressure ulcers is lacking. To evaluate the effect of a pressure mapping system on pressure ulcer prevalence and incidence in a hospital setting. Pragmatic randomised controlled trial. A geriatric/internal medical ward with 26 beds in a Swedish university hospital. 190 patients were recruited (intervention: n=91; control: n=99) over a period of 9 months. Patients were eligible if they were over 50 years old, admitted to the ward between Sunday 4pm and Friday 4pm, and expected to stay in the ward ≥3 days. The continuous bedside pressure mapping system displays the patient's pressure points in real-time colour imagery showing how pressure is distributed at the body-mat interface. The system gives immediate feedback to staff about the patient's pressure points, facilitating preventive interventions related to repositioning. It was used from admittance to discharge from the ward (or 14 days at most). Both intervention and control groups received standard pressure ulcer prevention care. No significant difference in the prevalence and incidence of pressure ulcers was shown between intervention and control groups. The prevalence of pressure ulcers in the intervention group was 24.2% on day 1 and 28.2% on day 14. In the control group the corresponding numbers were 18.2% and 23.8%. Seven of 69 patients (10.1%) in the intervention group and seven of 81 patients (8.6%) in the control group who had no pressure ulcers on admission developed category 1 and category 2 ulcers during their hospital stay. The incidence rate ratio between the intervention and control groups was 1.13 (95% CI: 0.34-3.79). This study failed to demonstrate a beneficial effect of a pressure mapping system on pressure ulcer prevalence and incidence. However, the study could have increased staff awareness and focus on pressure ulcer prevention, thus affecting the prevalence and incidence of pressure ulcers in a positive way in both study groups. It is important to further investigate the experience of the multidisciplinary team and the patients regarding their use of the pressure mapping system, as well as strengths and weaknesses of the system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance back-deduction from a loading to flow coefficient map: Application to radial turbine

NASA Astrophysics Data System (ADS)

Carbonneau, Xavier; Binder, Nicolas

2012-12-01

Radial turbine stages are often used for applications requiring off-design operation, as turbocharging for instance. The off-design ability of such stages is commonly analyzed through the traditional turbine map, plotting the reduced mass-flow against the pressure-ratio, for reduced-speed lines. However, some alternatives are possible, such as the flow-coefficient ( Ψ) to loading-coefficient ( φ) diagram where the pressure-ratio lines are actually straight lines, very convenient property to perform prediction. A robust method re-creating this map from a predicted Ψ-φ diagram is needed. Recent work has shown that this back-deduction quality, without the use of any loss models, depends on the knowledge of an intermediate pressure-ratio. A modelization of this parameter is then proposed. The comparison with both experimental and CFD results is presented, with quite good agreement for mass flow rate and rotational speed, and for the intermediate pressure ratio. The last part of the paper is dedicated to the application of the intermediate pressure-ratio knowledge to the improvement of the deduction of the pressure ratio lines in the Ψ-φ diagram. Beside this improvement, the back-deduction method of the classical map is structured, applied and evaluated.

Seafloor Pressure Array Studies at Ultra-Low Frequencies

DTIC Science & Technology

1991-01-01

broadband instrument design and deployment. In order to measure broadband noise routinely, a low frequency pressure gauge designed for deep ocean...below the microseism band (Moore et al, 1981). A differential pressure gauge , developed for low frequency recordings by Cox et al (1984) and sensitive to...design differential pressure gauge (Cox et al, 1984) with a sensitivity -3- ULF Seafloor Pressure Array Studies range of 0.01-5 Hz. The high

Method for solvent extraction with near-equal density solutions

DOEpatents

Birdwell, Joseph F.; Randolph, John D.; Singh, S. Paul

2001-01-01

Disclosed is a modified centrifugal contactor for separating solutions of near equal density. The modified contactor has a pressure differential establishing means that allows the application of a pressure differential across fluid in the rotor of the contactor. The pressure differential is such that it causes the boundary between solutions of near-equal density to shift, thereby facilitating separation of the phases. Also disclosed is a method of separating solutions of near-equal density.

A Bifurcation Problem for a Nonlinear Partial Differential Equation of Parabolic Type,

DTIC Science & Technology

NONLINEAR DIFFERENTIAL EQUATIONS, INTEGRATION), (*PARTIAL DIFFERENTIAL EQUATIONS, BOUNDARY VALUE PROBLEMS), BANACH SPACE , MAPPING (TRANSFORMATIONS), SET THEORY, TOPOLOGY, ITERATIONS, STABILITY, THEOREMS

14 CFR 23.365 - Pressurized cabin loads.

Code of Federal Regulations, 2011 CFR

2011-01-01

... landing. (d) The airplane structure must be strong enough to withstand the pressure differential loads... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23... structure must be strong enough to withstand the flight loads combined with pressure differential loads from...

Tectonic stresses in the lithosphere: constraints provided by the experimental deformation of rocks.

USGS Publications Warehouse

Kirby, S.H.

1980-01-01

The strengths of rocks clearly place an upper limit on the stress that can be sustained by the upper half of the lithosphere. Laboratory data on rock rheology are generally lacking at intermediate temperatures and pressures on the important rock types expected in the lithosphere, so a definitive accounting of the strength distribution with depth in the upper lithosphere is presently unattainable. Analogies are drawn between the fragmentary strength data on slicates at intermediate temperature and the more extensive experimental data on marble and limestone, and several tentative conclusions are drawn: First, brittle processes, such as faulting and cataclasis, are expected to control rock strength at low pressures and temperatures. The strengths associated with these brittle mechanisms increase rapidly with increasing effective pressure and are relatively insensitive to temperature and strain rate. Second, the transitions between brittle and ductile processes occur at critical values of the least principal stress sigma3. I suggest that the concept of the deformation mechanism map of Ashby (1972) be extended to brittle-ductile transitions by normalizing the applied differential stress sigma by sigma3, i.e., the transitions occur at critical values of sigma/sigma3. -from Author

Spaces of differential forms and maps with controlled distortion

NASA Astrophysics Data System (ADS)

Vodop'yanov, Sergei K.

2010-09-01

We study necessary and sufficient conditions for an approximately differentiable map f\\colon M\\to M' between Riemannian manifolds to induce a bounded transfer operator of differential forms with respect to the norms of Lebesgue spaces. As a corollary, we see that every homeomorphism f\\colon M\\to M' of class \\operatorname{ACL}(M) whose transfer operator of differential forms with norm in L_p is an isomorphism must necessarily be either quasi-conformal or quasi-isometric. We give some applications of our results to the study of the functoriality of cohomology in Lebesgue spaces.

Mathematical Modelling of CSF Pulsatile Flow in Aqueduct Cerebri.

PubMed

Czosnyka, Zofia; Kim, Dong-Joo; Balédent, Olivier; Schmidt, Eric A; Smielewski, Peter; Czosnyka, Marek

2018-01-01

The phase-contrast MRI technique permits the non-invasive assessment of CSF movements in cerebrospinal fluid cavities of the central nervous system. Of particular interest is pulsatile cerebrospinal fluid (CSF) flow through the aqueduct cerebri. It is allegedly increased in hydrocephalus, having potential diagnostic value, although not all scientific reports contain unequivocally positive conclusions. For the mathematical simulation of CSF flow, we used a computational model of cerebrospinal blood/fluid circulation designed by a former student as his PhD project. With this model, cerebral blood flow and CSF may be simulated in various vessels using a system of non-linear differential equations as time-varying signals. The amplitude of CSF flow seems to be positively related to the amplitude of pulse waveforms of intracranial pressure (ICP) in situations where mean ICP increases, such as during simulated infusion tests and following step increases of resistance to CSF outflow. An additional positive association between the pulse amplitude of ICP and CSF flow can be seen during simulated increases in the amplitude of arterial pulses (without changes in mean arterial pressure, MAP). The opposite effect can be observed during step increases in the resistance of the aqueduct cerebri and with decreasing elasticity of the system, where the CSF flow amplitude and the ICP pulse amplitude are related inversely. Vasodilatation caused by both gradual decreases in MAP and by increases in PaCO2 provokes an elevation in the observed amplitude of pulsatile CSF flow. Preliminary results indicate that the pulsations of CSF flow may carry information about both CSF-circulatory and cerebral vasogenic components. In most cases, the pulsations of CSF flow are positively related to the pulse amplitudes of both arterial pressure and ICP and to a degree of cerebrovascular dilatation.

Mappings of Least Dirichlet Energy and their Hopf Differentials

NASA Astrophysics Data System (ADS)

Iwaniec, Tadeusz; Onninen, Jani

2013-08-01

The paper is concerned with mappings {h \\colon {X}} {{begin{array}{ll} onto \\ longrightarrow }} {{Y}} between planar domains having least Dirichlet energy. The existence and uniqueness (up to a conformal change of variables in {{X}}) of the energy-minimal mappings is established within the class {overline{fancyscript{H}}_2({X}, {Y})} of strong limits of homeomorphisms in the Sobolev space {fancyscript{W}^{1,2}({X}, {Y})} , a result of considerable interest in the mathematical models of nonlinear elasticity. The inner variation of the independent variable in {{X}} leads to the Hopf differential {hz overline{h_{bar{z}}} dz ⊗ dz} and its trajectories. For a pair of doubly connected domains, in which {{X}} has finite conformal modulus, we establish the following principle: A mapping {h in overline{fancyscript{H}}2 ({X}, {Y})} is energy-minimal if and only if its Hopf-differential is analytic in {{X}} and real along {partial {X}} . In general, the energy-minimal mappings may not be injective, in which case one observes the occurrence of slits in {{X}} (cognate with cracks). Slits are triggered by points of concavity of {{Y}} . They originate from {partial {X}} and advance along vertical trajectories of the Hopf differential toward {{X}} where they eventually terminate, so no crosscuts are created.

Application of a methodology for categorizing and differentiating urban soundscapes using acoustical descriptors and semantic-differential attributes.

PubMed

Torija, Antonio J; Ruiz, Diego P; Ramos-Ridao, A F

2013-07-01

A subjective and physical categorization of an ambient sound is the first step to evaluate the soundscape and provides a basis for designing or adapting this ambient sound to match people's expectations. For this reason, the main goal of this work is to develop a categorization and differentiation analysis of soundscapes on the basis of acoustical and perceptual variables. A hierarchical cluster analysis, using 15 semantic-differential attributes and acoustical descriptors to include an equivalent sound-pressure level, maximum-minimum sound-pressure level, impulsiveness of the sound-pressure level, sound-pressure level time course, and spectral composition, was conducted to classify soundscapes into different typologies. This analysis identified 15 different soundscape typologies. Furthermore, based on a discriminant analysis the acoustical descriptors, the crest factor (impulsiveness of the sound-pressure level), and the sound level at 125 Hz were found to be the acoustical variables with the highest impact in the differentiation of the recognized types of soundscapes. Finally, to determine how the different soundscape typologies differed from each other, both subjectively and acoustically, a study was performed.

Role of interfacial bonding in the design and realization of Magnetically Applied Pressure Shear (MAPS) experiments

NASA Astrophysics Data System (ADS)

Ding, Jow; Alexander, C. Scott

2017-06-01

MAPS (Magnetically Applied Pressure Shear) is a new technique that can be used to explore the material behavior under dynamic compression-shear loadings at strain rates and pressures that are much higher than those that can be achieved by gas-gun driven pressure shear experiments. A significant challenge for MAPS is the transmission of large shear stress through material interfaces. In this study, numerical simulations were used to gain insights on the behavior of the interface between molybdenum, which is the driver, and zirconia, the anvil, in MAPS experiments. Molybdenum was stressed into the plastic regime and zirconia stayed elastic but appeared to have incurred some spall damage at the later stage of the experiments. By including damage for the anvil and interfacial sliding in the simulations, both the longitudinal and transverse velocity data were able to be reasonably simulated. The results indicate that the interfacial slip appears to usually occur at the beginning stage of the shear loading when the pressure is relatively low. After the pressure reaches a certain level, the shear stress could be fully transmitted. Some other possible experiment designs to minimize the role of interface in MAPS are discussed. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Sensitivity of rough differential equations: An approach through the Omega lemma

NASA Astrophysics Data System (ADS)

Coutin, Laure; Lejay, Antoine

2018-03-01

The Itô map gives the solution of a Rough Differential Equation, a generalization of an Ordinary Differential Equation driven by an irregular path, when existence and uniqueness hold. By studying how a path is transformed through the vector field which is integrated, we prove that the Itô map is Hölder or Lipschitz continuous with respect to all its parameters. This result unifies and weakens the hypotheses of the regularity results already established in the literature.

Postcontrast T1 Mapping for Differential Diagnosis of Recurrence and Radionecrosis after Gamma Knife Radiosurgery for Brain Metastasis.

PubMed

Wang, B; Zhang, Y; Zhao, B; Zhao, P; Ge, M; Gao, M; Ding, F; Xu, S; Liu, Y

2018-06-01

The differential diagnosis of radionecrosis and tumor recurrence in brain metastases is challenging. We investigated the diagnostic efficiency of postcontrast T1 mapping in solving this problem. Between March 2016 and June 2017, fifty-six patients with brain metastases who underwent contrast-enhanced cerebral T1 mapping were recruited for this prospective study. The findings revealed new enhancement after gamma knife radiosurgery. The subjects were assigned to radionecrosis and recurrence groups based on follow-up (median, 11.5 months) and histopathologic results. T1 values of lesions 5 (T1 5min ) and 60 (T1 60min ) minutes after administration of contrast agent and their difference (T1 differ ) were compared between the 2 groups with the 2-tailed Mann-Whitney U test. Receiver operating characteristic curves were used to determine the optimum cutoff values for differential diagnosis. There were significant differences between the 2 groups in T1 5min , T1 60min , and T1 differ values ( P = .012, P = .004, and P < .001, respectively). Relative to T1 5min and T1 60min , T1 differ exhibited greater sensitivity and specificity ( P < .001, respectively) in identifying radionecrosis. The optimum T1 differ value for differential diagnosis was 71.1 ms (area under the curve = 0.97; 95% CI, 0.93-1.00), with sensitivity and specificity of 81.5% and 96.5%, respectively. Postcontrast T1 mapping is optimal for the differential diagnosis of radionecrosis and tumor recurrence. Among T1 parameters, T1 differ is the most powerful parameter for differential diagnosis. Advantages in terms of quantitative analysis and high resolution portend the wide use of postcontrast T1 mapping in the future. © 2018 by American Journal of Neuroradiology.

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

Dubovsky, E.V.; Curtis, J.J.; Luke, R.G.

Impaired function of renal allografts caused by recurrent disease or rejection is often accompanied by hypertension. The etiology of persistent severe hypertension in recipients with good renal function is more difficult to explain. To study this problem, 33 patients with mean arterial pressure (MAP) > 105 mm Hg (at least one year after transplantation) were tested. When compared to a normotensive group, they were found to have increased renal vascular resistance, lower ERPF, and increased renin-angiotensin activity. The effect of Captopril, a converting enzyme inhibitor, was studied to evaluate the role of angiotension. The paper concludes that Captopril test maymore » permit differentiation between native kidney-dependent hypertension (increase in ERPF) and functionally active renal artery stenosis (decline in ERPF) in patients with persistent hypertension and good renal function.« less

Adaptive genomic divergence under high gene flow between freshwater and brackish-water ecotypes of prickly sculpin (Cottus asper) revealed by Pool-Seq.

PubMed

Dennenmoser, Stefan; Vamosi, Steven M; Nolte, Arne W; Rogers, Sean M

2017-01-01

Understanding the genomic basis of adaptive divergence in the presence of gene flow remains a major challenge in evolutionary biology. In prickly sculpin (Cottus asper), an abundant euryhaline fish in northwestern North America, high genetic connectivity among brackish-water (estuarine) and freshwater (tributary) habitats of coastal rivers does not preclude the build-up of neutral genetic differentiation and emergence of different life history strategies. Because these two habitats present different osmotic niches, we predicted high genetic differentiation at known teleost candidate genes underlying salinity tolerance and osmoregulation. We applied whole-genome sequencing of pooled DNA samples (Pool-Seq) to explore adaptive divergence between two estuarine and two tributary habitats. Paired-end sequence reads were mapped against genomic contigs of European Cottus, and the gene content of candidate regions was explored based on comparisons with the threespine stickleback genome. Genes showing signals of repeated differentiation among brackish-water and freshwater habitats included functions such as ion transport and structural permeability in freshwater gills, which suggests that local adaptation to different osmotic niches might contribute to genomic divergence among habitats. Overall, the presence of both repeated and unique signatures of differentiation across many loci scattered throughout the genome is consistent with polygenic adaptation from standing genetic variation and locally variable selection pressures in the early stages of life history divergence. © 2016 John Wiley & Sons Ltd.

Differentiation of benign and malignant breast lesions by mechanical imaging

PubMed Central

Kearney, Thomas; Pollak, Stanley B.; Rohatgi, Chand; Sarvazyan, Noune; Airapetian, Suren; Browning, Stephanie; Sarvazyan, Armen

2009-01-01

Mechanical imaging yields tissue elasticity map and provides quantitative characterization of a detected pathology. The changes in the surface stress patterns as a function of applied load provide information about the elastic composition and geometry of the underlying tissue structures. The objective of this study is the clinical evaluation of breast mechanical imager for breast lesion characterization and differentiation between benign and malignant lesions. The breast mechanical imager includes a probe with pressure sensor array, an electronic unit providing data acquisition from the pressure sensors and communication with a touch-screen laptop computer. We have developed an examination procedure and algorithms to provide assessment of breast lesion features such as hardness related parameters, mobility, and shape. A statistical Bayesian classifier was constructed to distinguish between benign and malignant lesions by utilizing all the listed features as the input. Clinical results for 179 cases, collected at four different clinical sites, have demonstrated that the breast mechanical imager provides a reliable image formation of breast tissue abnormalities and calculation of lesion features. Malignant breast lesions (histologically confirmed) demonstrated increased hardness and strain hardening as well as decreased mobility and longer boundary length in comparison with benign lesions. Statistical analysis of differentiation capability for 147 benign and 32 malignant lesions revealed an average sensitivity of 91.4% and specificity of 86.8% with a standard deviation of ±6.1%. The area under the receiver operating characteristic curve characterizing benign and malignant lesion discrimination is 86.1% with the confidence interval ranging from 80.3 to 90.9%, with a significance level of P = 0.0001 (area = 50%). The multisite clinical study demonstrated the capability of mechanical imaging for characterization and differentiation of benign and malignant breast lesions. We hypothesize that the breast mechanical imager has the potential to be used as a cost effective device for cancer diagnostics that could reduce the benign biopsy rate, serve as an adjunct to mammography and to be utilized as a screening device for breast cancer detection. PMID:19306059

Differences in blood pressure by measurement technique in neurocritically ill patients: A technological assessment.

PubMed

Lele, Abhijit V; Wilson, Daren; Chalise, Prabhakar; Nazzaro, Jules; Krishnamoorthy, Vijay; Vavilala, Monica S

2018-01-01

Blood pressure data may vary by measurement technique. We performed a technological assessment of differences in blood pressure measurement between non-invasive blood pressure (NIBP) and invasive arterial blood pressure (ABP) in neurocritically ill patients. After IRB approval, a prospective observational study was performed to study differences in systolic blood pressure (SBP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) values measured by NIBP arm, ABP at level of the phlebostatic axis (ABP heart) and ABP at level of the external auditory meatus (ABP brain) at 30 and 45-degree head of bed elevation (HOB) using repeated measure analysis of covariance and correlation coefficients. Overall, 168 patients were studied with median age of 57 ± 15 years, were mostly female (57%), with body mass index ≤30 (66%). Twenty-three percent (n = 39) had indwelling intracranial pressure monitors, and 19.7% (n = 33) received vasoactive agents. ABP heart overestimated ABP brain for SBP (11.5 ± 2.7 mmHg, p < .001), MAP (mean difference 13.3 ± 0.5 mmHg, p < .001) and CPP (13.4 ± 3.2 mmHg, p < .001). ABP heart overestimated NIBP arm for SBP (8 ± 1.5 mmHg, p < .001), MAP (mean difference 8.6 ± 0.8 mmHg, p < .001), and CPP (mean difference 9.8 ± 3.2 mmHg, p < .001). Regardless of HOB elevation, ABP heart overestimates MAP compared to ABP brain and NIBP arm. Using ABP heart data overestimates CPP and may be responsible for not achieving SBP, MAP or CPP targets aimed at the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-invasive pulmonary blood flow analysis and blood pressure mapping derived from 4D flow MRI

NASA Astrophysics Data System (ADS)

Delles, Michael; Rengier, Fabian; Azad, Yoo-Jin; Bodenstedt, Sebastian; von Tengg-Kobligk, Hendrik; Ley, Sebastian; Unterhinninghofen, Roland; Kauczor, Hans-Ulrich; Dillmann, Rüdiger

2015-03-01

In diagnostics and therapy control of cardiovascular diseases, detailed knowledge about the patient-specific behavior of blood flow and pressure can be essential. The only method capable of measuring complete time-resolved three-dimensional vector fields of the blood flow velocities is velocity-encoded magnetic resonance imaging (MRI), often denoted as 4D flow MRI. Furthermore, relative pressure maps can be computed from this data source, as presented by different groups in recent years. Hence, analysis of blood flow and pressure using 4D flow MRI can be a valuable technique in management of cardiovascular diseases. In order to perform these tasks, all necessary steps in the corresponding process chain can be carried out in our in-house developed software framework MEDIFRAME. In this article, we apply MEDIFRAME for a study of hemodynamics in the pulmonary arteries of five healthy volunteers. The study included measuring vector fields of blood flow velocities by phase-contrast MRI and subsequently computing relative blood pressure maps. We visualized blood flow by streamline depictions and computed characteristic values for the left and the right pulmonary artery (LPA and RPA). In all volunteers, we observed a lower amount of blood flow in the LPA compared to the RPA. Furthermore, we visualized blood pressure maps using volume rendering and generated graphs of pressure differences between the LPA, the RPA and the main pulmonary artery. In most volunteers, blood pressure was increased near to the bifurcation and in the proximal LPA, leading to higher average pressure values in the LPA compared to the RPA.

Optical zero-differential pressure switch and its evaluation in a multiple pressure measuring system

NASA Technical Reports Server (NTRS)

Powell, J. A.

1977-01-01

The design of a clamped-diaphragm pressure switch is described in which diaphragm motion is detected by a simple fiber-optic displacement sensor. The switch was evaluated in a pressure measurement system where it detected the zero crossing of the differential pressure between a static test pressure and a tank pressure that was periodically ramped from near zero to fullscale gage pressure. With a ramping frequency of 1 hertz and a full-scale tank pressure of 69 N/sq cm gage (100 psig), the switch delay was as long as 2 milliseconds. Pressure measurement accuracies were 0.25 to 0.75 percent of full scale. Factors affecting switch performance are also discussed.

Nonlinear systems dynamics in cardiovascular physiology: The heart rate delay map and lower body negative pressure

NASA Technical Reports Server (NTRS)

Hooker, John C.

1990-01-01

A preliminary study of the applicability of nonlinear dynamic systems analysis techniques to low body negative pressure (LBNP) studies. In particular, the applicability of the heart rate delay map is investigated. It is suggested that the heart rate delay map has potential as a supplemental tool in the assessment of subject performance in LBNP tests and possibly in the determination of susceptibility to cardiovascular deconditioning with spaceflight.

A Genome-wide Combinatorial Strategy Dissects Complex Genetic Architecture of Seed Coat Color in Chickpea

PubMed Central

Bajaj, Deepak; Das, Shouvik; Upadhyaya, Hari D.; Ranjan, Rajeev; Badoni, Saurabh; Kumar, Vinod; Tripathi, Shailesh; Gowda, C. L. Laxmipathi; Sharma, Shivali; Singh, Sube; Tyagi, Akhilesh K.; Parida, Swarup K.

2015-01-01

The study identified 9045 high-quality SNPs employing both genome-wide GBS- and candidate gene-based SNP genotyping assays in 172, including 93 cultivated (desi and kabuli) and 79 wild chickpea accessions. The GWAS in a structured population of 93 sequenced accessions detected 15 major genomic loci exhibiting significant association with seed coat color. Five seed color-associated major genomic loci underlying robust QTLs mapped on a high-density intra-specific genetic linkage map were validated by QTL mapping. The integration of association and QTL mapping with gene haplotype-specific LD mapping and transcript profiling identified novel allelic variants (non-synonymous SNPs) and haplotypes in a MATE secondary transporter gene regulating light/yellow brown and beige seed coat color differentiation in chickpea. The down-regulation and decreased transcript expression of beige seed coat color-associated MATE gene haplotype was correlated with reduced proanthocyanidins accumulation in the mature seed coats of beige than light/yellow brown seed colored desi and kabuli accessions for their coloration/pigmentation. This seed color-regulating MATE gene revealed strong purifying selection pressure primarily in LB/YB seed colored desi and wild Cicer reticulatum accessions compared with the BE seed colored kabuli accessions. The functionally relevant molecular tags identified have potential to decipher the complex transcriptional regulatory gene function of seed coat coloration and for understanding the selective sweep-based seed color trait evolutionary pattern in cultivated and wild accessions during chickpea domestication. The genome-wide integrated approach employed will expedite marker-assisted genetic enhancement for developing cultivars with desirable seed coat color types in chickpea. PMID:26635822

Relations of Central Hemodynamics and Aortic Stiffness with Left Ventricular Structure and Function: The Framingham Heart Study.

PubMed

Kaess, Bernhard M; Rong, Jian; Larson, Martin G; Hamburg, Naomi M; Vita, Joseph A; Cheng, Susan; Aragam, Jayashree; Levy, Daniel; Benjamin, Emelia J; Vasan, Ramachandran S; Mitchell, Gary F

2016-03-25

The differing relations of steady and pulsatile components of central hemodynamics and aortic stiffness with cardiac dimensions and function have not been fully elucidated. Central hemodynamics and carotid-femoral pulse wave velocity (CFPWV, a measure of aortic stiffness) were measured by arterial tonometry in 5799 participants of the Framingham Heart Study (mean age 51 years, 54% women) and related to echocardiographic left ventricular (LV) dimensions and systolic and diastolic function using multivariable-adjusted partial Pearson correlations. Mean arterial pressure (MAP, steady component of central blood pressure) was associated positively with LV wall thickness (r=0.168; P<0.0001) but showed only a weak direct association with LV diastolic dimension (r=0.035, P=0.006). Central pulse pressure (pulsatile component of central blood pressure) showed a direct correlation with both LV diastolic dimension and LV wall thickness (r=0.08 and 0.044, both P<0.0001 in multivariable models that included MAP). CFPWV was not associated with LV structure (all P≥0.27) in MAP-adjusted models). Both MAP and CFPWV were associated inversely with LV diastolic function (E'; r=-0.140 and -0.153, respectively; both P<0.0001), and these associations persisted after additional adjustment for LV mass and central pulse pressure (r=-0.142 and -0.108, both P<0.0001). MAP and CFPWV were not associated with LV fractional shortening (P≥0.10), whereas central pulse pressure was positively related (r=0.064, P<0.0001). Pulsatile and steady components of central pressure are conjointly yet variably related to LV structure. CFPWV is related to LV diastolic function but not to systolic function. Additional studies are warranted to confirm these observations. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

On Small Disturbance Ascent Vent Behavior

NASA Technical Reports Server (NTRS)

Woronowicz, Michael

2015-01-01

As a spacecraft undergoes ascent in a launch vehicle, its ambient pressure environment transitions from one atmosphere to high vacuum in a matter of a few minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. These pressure differentials are often restricted to low levels to prevent violation of container integrity. Such vents usually consist of fixed orifices, ducts, or combinations of both. Duct conductance behavior is fundamentally different from that for orifices in pressure driven flows governing the launch vehicle ascent depressurization environment. Duct conductance is governed by the average pressure across its length, while orifice conductance is dictated by a pressure ratio. Hence, one cannot define a valid equivalent orifice for a given duct across a range of pressure levels. This presentation discusses development of expressions for these two types of vent elements in the limit of small pressure differentials, explores conditions for their validity, and compares their features regarding ascent depressurization performance.

Averaged ratio between complementary profiles for evaluating shape distortions of map projections and spherical hierarchical tessellations

NASA Astrophysics Data System (ADS)

Yan, Jin; Song, Xiao; Gong, Guanghong

2016-02-01

We describe a metric named averaged ratio between complementary profiles to represent the distortion of map projections, and the shape regularity of spherical cells derived from map projections or non-map-projection methods. The properties and statistical characteristics of our metric are investigated. Our metric (1) is a variable of numerical equivalence to both scale component and angular deformation component of Tissot indicatrix, and avoids the invalidation when using Tissot indicatrix and derived differential calculus for evaluating non-map-projection based tessellations where mathematical formulae do not exist (e.g., direct spherical subdivisions), (2) exhibits simplicity (neither differential nor integral calculus) and uniformity in the form of calculations, (3) requires low computational cost, while maintaining high correlation with the results of differential calculus, (4) is a quasi-invariant under rotations, and (5) reflects the distortions of map projections, distortion of spherical cells, and the associated distortions of texels. As an indicator of quantitative evaluation, we investigated typical spherical tessellation methods, some variants of tessellation methods, and map projections. The tessellation methods we evaluated are based on map projections or direct spherical subdivisions. The evaluation involves commonly used Platonic polyhedrons, Catalan polyhedrons, etc. Quantitative analyses based on our metric of shape regularity and an essential metric of area uniformity implied that (1) Uniform Spherical Grids and its variant show good qualities in both area uniformity and shape regularity, and (2) Crusta, Unicube map, and a variant of Unicube map exhibit fairly acceptable degrees of area uniformity and shape regularity.

Multi-Fidelity Simulation of a Turbofan Engine With Results Zoomed Into Mini-Maps for a Zero-D Cycle Simulation

NASA Technical Reports Server (NTRS)

Turner, Mark G.; Reed, John A.; Ryder, Robert; Veres, Joseph P.

2004-01-01

A Zero-D cycle simulation of the GE90-94B high bypass turbofan engine has been achieved utilizing mini-maps generated from a high-fidelity simulation. The simulation utilizes the Numerical Propulsion System Simulation (NPSS) thermodynamic cycle modeling system coupled to a high-fidelity full-engine model represented by a set of coupled 3D computational fluid dynamic (CFD) component models. Boundary conditions from the balanced, steady state cycle model are used to define component boundary conditions in the full-engine model. Operating characteristics of the 3D component models are integrated into the cycle model via partial performance maps generated from the CFD flow solutions using one-dimensional mean line turbomachinery programs. This paper highlights the generation of the high-pressure compressor, booster, and fan partial performance maps, as well as turbine maps for the high pressure and low pressure turbine. These are actually "mini-maps" in the sense that they are developed only for a narrow operating range of the component. Results are compared between actual cycle data at a take-off condition and the comparable condition utilizing these mini-maps. The mini-maps are also presented with comparison to actual component data where possible.

Importance of Calibration Method in Central Blood Pressure for Cardiac Structural Abnormalities.

PubMed

Negishi, Kazuaki; Yang, Hong; Wang, Ying; Nolan, Mark T; Negishi, Tomoko; Pathan, Faraz; Marwick, Thomas H; Sharman, James E

2016-09-01

Central blood pressure (CBP) independently predicts cardiovascular risk, but calibration methods may affect accuracy of central systolic blood pressure (CSBP). Standard central systolic blood pressure (Stan-CSBP) from peripheral waveforms is usually derived with calibration using brachial SBP and diastolic BP (DBP). However, calibration using oscillometric mean arterial pressure (MAP) and DBP (MAP-CSBP) is purported to provide more accurate representation of true invasive CSBP. This study sought to determine which derived CSBP could more accurately discriminate cardiac structural abnormalities. A total of 349 community-based patients with risk factors (71±5years, 161 males) had CSBP measured by brachial oscillometry (Mobil-O-Graph, IEM GmbH, Stolberg, Germany) using 2 calibration methods: MAP-CSBP and Stan-CSBP. Left ventricular hypertrophy (LVH) and left atrial dilatation (LAD) were measured based on standard guidelines. MAP-CSBP was higher than Stan-CSBP (149±20 vs. 128±15mm Hg, P < 0.0001). Although they were modestly correlated (rho = 0.74, P < 0.001), the Bland-Altman plot demonstrated a large bias (21mm Hg) and limits of agreement (24mm Hg). In receiver operating characteristic (ROC) curve analyses, MAP-CSBP significantly better discriminated LVH compared with Stan-CSBP (area under the curve (AUC) 0.66 vs. 0.59, P = 0.0063) and brachial SBP (0.62, P = 0.027). Continuous net reclassification improvement (NRI) (P < 0.001) and integrated discrimination improvement (IDI) (P < 0.001) corroborated superior discrimination of LVH by MAP-CSBP. Similarly, MAP-CSBP better distinguished LAD than Stan-CSBP (AUC 0.63 vs. 0.56, P = 0.005) and conventional brachial SBP (0.58, P = 0.006), whereas Stan-CSBP provided no better discrimination than conventional brachial BP (P = 0.09). CSBP is calibration dependent and when oscillometric MAP and DBP are used, the derived CSBP is a better discriminator for cardiac structural abnormalities. © American Journal of Hypertension, Ltd 2016. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Backup Attitude Control Algorithms for the MAP Spacecraft

NASA Technical Reports Server (NTRS)

ODonnell, James R., Jr.; Andrews, Stephen F.; Ericsson-Jackson, Aprille J.; Flatley, Thomas W.; Ward, David K.; Bay, P. Michael

1999-01-01

The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. The MAP spacecraft will perform its mission, studying the early origins of the universe, in a Lissajous orbit around the Earth-Sun L(sub 2) Lagrange point. Due to limited mass, power, and financial resources, a traditional reliability concept involving fully redundant components was not feasible. This paper will discuss the redundancy philosophy used on MAP, describe the hardware redundancy selected (and why), and present backup modes and algorithms that were designed in lieu of additional attitude control hardware redundancy to improve the odds of mission success. Three of these modes have been implemented in the spacecraft flight software. The first onboard mode allows the MAP Kalman filter to be used with digital sun sensor (DSS) derived rates, in case of the failure of one of MAP's two two-axis inertial reference units. Similarly, the second onboard mode allows a star tracker only mode, using attitude and derived rate from one or both of MAP's star trackers for onboard attitude determination and control. The last backup mode onboard allows a sun-line angle offset to be commanded that will allow solar radiation pressure to be used for momentum management and orbit stationkeeping. In addition to the backup modes implemented on the spacecraft, two backup algorithms have been developed in the event of less likely contingencies. One of these is an algorithm for implementing an alternative scan pattern to MAP's nominal dual-spin science mode using only one or two reaction wheels and thrusters. Finally, an algorithm has been developed that uses thruster one shots while in science mode for momentum management. This algorithm has been developed in case system momentum builds up faster than anticipated, to allow adequate momentum management while minimizing interruptions to science. In this paper, each mode and algorithm will be discussed, and simulation results presented.

Halo Pressure Profile through the Skew Cross-power Spectrum of the Sunyaev-Zel’dovich Effect and CMB Lensing in Planck

NASA Astrophysics Data System (ADS)

Timmons, Nicholas; Cooray, Asantha; Feng, Chang; Keating, Brian

2017-11-01

We measure the cosmic microwave background (CMB) skewness power spectrum in Planck, using frequency maps of the HFI instrument and the Sunyaev-Zel’dovich (SZ) component map. The two-to-one skewness power spectrum measures the cross-correlation between CMB lensing and the thermal SZ effect. We also directly measure the same cross-correlation using the Planck CMB lensing map and the SZ map and compare it to the cross-correlation derived from the skewness power spectrum. We model fit the SZ power spectrum and CMB lensing-SZ cross-power spectrum via the skewness power spectrum to constrain the gas pressure profile of dark matter halos. The gas pressure profile is compared to existing measurements in the literature including a direct estimate based on the stacking of SZ clusters in Planck.

Real-Time Processing of Pressure-Sensitive Paint Images

DTIC Science & Technology

2006-12-01

intermediate or final data to the hard disk in 3D grid format. In addition to the pressure or pressure coefficient at every grid point, the saved file may...occurs. Nevertheless, to achieve an accurate mapping between 2D image coordinates and 3D spatial coordinates, additional parameters must be introduced. A...improved mapping between the 2D and 3D coordinates. In a more sophisticated approach, additional terms corresponding to specific deformation modes

Computing the Lyapunov spectrum of a dynamical system from an observed time series

NASA Technical Reports Server (NTRS)

Brown, Reggie; Bryant, Paul; Abarbanel, Henry D. I.

1991-01-01

The paper examines the problem of accurately determining, from an observed time series, the Liapunov exponents for the dynamical system generating the data. It is shown that, even with very large data sets, it is clearly advantageous to utilize local neighborhood-to-neighborhood mappings with higher-order Taylor series rather than just local linear maps. This procedure is demonstrated on the Henon and Ikeda maps of the plane itself, the Lorenz system of three ordinary differential equations, and the Mackey-Glass delay differential equation.

Integrated reservoir characterization and flow simulation for well targeting and reservoir management, Iagifu-Hedinia field, Southern Highlands Province, Papua New Guinea

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

Franklin, S.P.; Livingston, J.E.; Fitzmorris, R.E.

Infill drilling based on integrated reservoir characterization and flow simulation is increasing recoverable reserves by 20 MMBO, in lagifu-Hedinia Field (IHF). Stratigraphically-zoned models are input to window and full-field flow simulations, and results of the flow simulations target deviated and horizontal wells. Logging and pressure surveys facilitate detailed reservoir management. Flooding surfaces are the dominant control on differential depletion within and between reservoirs. The primary reservoir is the basal Cretaceous Toro Sandstone. Within the IHF, Toro is a 100 m quartz sandstone composed of stacked, coarsening-upward parasequences within a wave-dominated deltaic complex. Flooding surfaces are used to form a hydraulicmore » zonation. The zonation is refined using discontinuities in RIFT pressure gradients and logs from development wells. For flow simulation, models use 3D geostatistical techniques. First, variograms defining spatial correlation are developed. The variograms are used to construct 3D porosity and permeability models which reflect the stratigraphic facies models. Structure models are built using dipmeter, biostratigraphic, and surface data. Deviated wells often cross axial surfaces and geometry is predicted from dip domain and SCAT. Faults are identified using pressure transient data and dipmeter. The Toro reservoir is subnormally pressured and fluid contacts are hydrodynamically tilted. The hydrodynamic flow and tilted contacts are modeled by flow simulation and constrained by maps of the potentiometric surface.« less

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.

T1ρ is superior to T2 mapping for the evaluation of articular cartilage denaturalization with osteoarthritis: radiological-pathological correlation after total knee arthroplasty.

PubMed

Takayama, Yukihisa; Hatakenaka, Masamitsu; Tsushima, Hidetoshi; Okazaki, Ken; Yoshiura, Takashi; Yonezawa, Masato; Nishikawa, Kei; Iwamoto, Yukihide; Honda, Hiroshi

2013-04-01

We compared the diagnostic performance of T1ρ and T2 mappings in the evaluation of denatured articular cartilage with osteoarthritis of the knee. 2D-Sagittal T1ρ and T2 mappings of the knee were obtained from 16 patients before total knee arthroplasty. After surgery, specimens of the femur and tibia were regionally segmented according to a 5-point scale of the severity of denaturalization. The T1ρ and T2 values in the full thickness of the articular cartilage in each region were measured by two observers. The two mappings were compared for their ability to differentiate between normal and denatured articular cartilage and also for their usefulness in grading the severity of the denaturalization using the area under receiver operating characteristic curves (Az). A p<0.05 was considered significant for each analysis. The T1ρ mapping showed a significantly higher Az value than the T2 mapping for the differentiation between normal and denatured articular cartilage (p<0.05). Regarding the assessment of the severity of denaturalization, T1ρ mapping could differentiate between normal and mild denaturalization (p<0.05), but T2 mapping could not. However, there were no significant differences between the two mappings in the discrimination of mild versus moderate denaturalization or of moderate versus severe denaturalization. The two observers showed good agreement in the results (intraclass correlation coefficient=0.81 for T1ρ and 0.92 for T2). T1ρ mapping is superior to T2 mapping for the evaluation of denatured articular cartilage with osteoarthritis of the knee. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Stress field modelling from digital geological map data

NASA Astrophysics Data System (ADS)

Albert, Gáspár; Barancsuk, Ádám; Szentpéteri, Krisztián

2016-04-01

To create a model for the lithospheric stress a functional geodatabase is required which contains spatial and geodynamic parameters. A digital structural-geological map is a geodatabase, which usually contains enough attributes to create a stress field model. Such a model is not accurate enough for engineering-geological purposes because simplifications are always present in a map, but in many cases maps are the only sources for a tectonic analysis. The here presented method is designed for field geologist, who are interested to see the possible realization of the stress field over the area, on which they are working. This study presents an application which can produce a map of 3D stress vectors from a kml-file. The core application logic is implemented on top of a spatially aware relational database management system. This allows rapid and geographically accurate analysis of the imported geological features, taking advantage of standardized spatial algorithms and indexing. After pre-processing the map features in a GIS, according to the Type-Property-Orientation naming system, which was described in a previous study (Albert et al. 2014), the first stage of the algorithm generates an irregularly spaced point cloud by emitting a pattern of points within a user-defined buffer zone around each feature. For each point generated, a component-wise approximation of the tensor field at the point's position is computed, derived from the original feature's geodynamic properties. In a second stage a weighted moving average method calculates the stress vectors in a regular grid. Results can be exported as geospatial data for further analysis or cartographic visualization. Computation of the tensor field's components is based on the implementation of the Mohr diagram of a compressional model, which uses a Coulomb fracture criterion. Using a general assumption that the main principal stress must be greater than the stress from the overburden, the differential stress is calculated from the fracture criterion. The calculation includes the gravitational acceleration, the average density of rocks and the experimental 60 degree of the fracture angle from the normal of the fault plane. This way, the stress tensors are calculated as absolute pressure values per square meters on both sides of the faults. If the stress from the overburden is greater than 1 bar (i.e. the faults are buried), a confined compression would be present. Modelling this state of stress may result a confusing pattern of vectors, because in a confined position the horizontal stress vectors may point towards structures primarily associated with extension. To step over this, and to highlight the variability in the stress-field, the model calculates the vectors directly from the differential stress (practically subtracting the minimum principal stress from the critical stress). The result of the modelling is a vector map, which theoretically represents the minimum tectonic pressure in the moment, when the rock body breaks from an initial state. This map - together with the original fault-map - is suitable for determining those areas where unrevealed tectonic, sedimentary and lithological structures are possibly present (e.g. faults, sub-basins and intrusions). With modelling different deformational phases on the same area, change of the stress vectors can be detected which reveals not only the varying directions of the principal stresses, but the tectonic-driven sedimentation patterns too. The decrease of necessary critical stress in the case of a possible reactivation of a fault in subsequent deformation phase can be managed with the down-ranking of the concerning structural elements. Reference: Albert G., Ungvári ZS., Szentpéteri K. 2014: Modeling the present day stress field of the Pannonian Basin from neotectonic maps - In: Beqiraj A, Ionescu C, Christofides G, Uta A, Beqiraj Goga E, Marku S (eds.) Proceedings XX Congress of the Carpathian-Balkan Geological Association. Tirana: p. 2.

A U-shaped Association between Blood Pressure and Cognitive Impairment in Chinese Elderly

PubMed Central

Lv, Yue-Bin; Zhu, Peng-Fei; Yin, Zhao-Xue; Kraus, Virginia Byers; Threapleton, Diane; Chei, Choy-Lye; Brasher, Melanie Sereny; Zhang, Juan; Qian, Han-Zhu; Mao, Chen; Matchar, David Bruce; Luo, Jie-Si; Zeng, Yi; Shi, Xiao-Ming

2017-01-01

Objectives Higher or lower blood pressure may relate to cognitive impairment, while the relationship between blood pressure and cognitive impairment among the elderly is not well-studied. The study objective was to determine whether blood pressure is associated with cognitive impairment in the elderly, and, if so, to accurately describe the association. Design Cross-sectional data from the sixth wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) conducted in 2011 Setting Community-based setting in longevity areas in China Participants 7,144 Chinese elderly aged 65 years and older were included in the sample Measures Systolic blood pressures (SBP) and diastolic blood pressures (DBP) were measured, pulse pressure (PP) was calculated as (SBP)-(DBP) and mean arterial pressures (MAP) was calculated as 1/3(SBP) + 2/3(DBP). Cognitive function was assessed via a validated Mini-Mental State Examination (MMSE). Results Based on the results of generalized additive models (GAMs), U-shaped associations were identified between cognitive impairment and SBP, DBP, PP and MAP. The cut-points at which risk for cognitive impairment (MMSE<24) was minimized were determined by quadratic models as 141 mmHg, 85 mmHg, 62 mmHg and 103 mmHg, respectively. In the logistic models, U-shaped associations remained for SBP, DBP, and MAP but not PP. Below the identified cut-points, each 1mmHg decrease in blood pressure corresponded to 0.7%, 1.1%, and 1.1% greater risk in the risk of cognitive impairment, respectively. Above the cut-points, each 1mmHg increase in blood pressure corresponded to 1.2%, 1.8%, and 2.1% greater risk of cognitive impairment for SBP, DBP and MAP, respectively. Conclusion A U-shaped association between blood pressure and cognitive function in an elderly Chinese population was found. Recognition of these instances is important identifying the high-risk population for cognitive impairment and to individualize blood pressure management for cognitive impairment prevention. PMID:28126139

Spacecraft compartment venting

NASA Astrophysics Data System (ADS)

Scialdone, John J.

1998-10-01

At various times, concerns have been expressed that rapid decompressions of compartments of gas pockets and thermal blankets during spacecraft launches may have caused pressure differentials across their walls sufficient to cause minor structural failures, separations of adhesively-joined parts, ballooning, and flapping of blankets. This paper presents a close form equation expressing the expected pressure differentials across the walls of a compartment as a function of the external to the volume pressure drops, the pressure at which the rates occur and the vent capability of the compartment. The pressure profiles measured inside the shrouds of several spacecraft propelled by several vehicles and some profiles obtained from ground vacuum systems have been included. The equation can be used to design the appropriate vent, which will preclude excessive pressure differentials. Precautions and needed approaches for the evaluations of the expected pressures have been indicated. Methods to make a rapid assessment of the response of the compartment to rapid external pressure drops have been discussed. These are based on the evaluation of the compartment vent flow conductance, the volume and the length of time during which the rapid pressure drop occurs.

Spacecraft Compartment Venting

NASA Technical Reports Server (NTRS)

Scialdone, John J.

1998-01-01

At various time concerns have been expressed that rapid decompressions of compartments of gas pockets and thermal blankets during spacecraft launches may have caused pressure differentials across their walls sufficient to cause minor structural failures, separations of adhesively-joined parts, ballooning, and flapping of blankets. This paper presents a close form equation expressing the expected pressure differentials across the walls of a compartment as a function of the external to the volume pressure drops, the pressure at which the rates occur and the vent capability of the compartment. The pressure profiles measured inside the shrouds of several spacecraft propelled by several vehicles and some profiles obtained from ground vacuum systems have been included. The equation can be used to design the appropriate vent, which will preclude excessive pressure differentials. Precautions and needed approaches for the evaluations of the expected pressures have been indicated. Methods to make a rapid assessment of the response of the compartment to rapid external pressure drops have been discussed. These are based on the evaluation of the compartment vent flow conductance, the volume and the length of time during which the rapid pressure drop occurs.

The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

NASA Astrophysics Data System (ADS)

Nakajima, Hideko Heidi; Pisano, Dominic V.; Merchant, Saumil N.; Rosowski, John J.

2011-11-01

Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability is not fully understood. We use intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Simultaneous measurement of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) quantifies the complex differential pressure across the cochlear partition, the stimulus that excites the partition. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure are measured simultaneously for various sizes of SCD followed by SCD patching. At low frequencies (<600 Hz) our results show that SCD decreases the pressure in both SV and ST, as well as differential pressure, and these effects become more pronounced as dehiscence size is increased. For frequencies above 1 kHz, the smallest pinpoint dehiscence can have the larger effect on the differential pressure in some ears. These effects due to SCD are reversible by patching the dehiscence.

Pressure compensated flow control valve

DOEpatents

Minteer, Daniel J.

1999-01-01

The invention is an air flow control valve which is capable of maintaining a constant flow at the outlet despite changes in the inlet or outlet pressure. The device consists of a shell assembly with an inlet chamber and outlet chamber separated by a separation plate. The chambers are connected by an orifice. Also located within the inlet chamber is a port controller assembly. The port controller assembly consists of a differential pressure plate and port cap affixed thereon. The cap is able to slide in and out of the orifice separating the inlet and outlet chambers. When the pressure differential is sufficient, the differential pressure plate rises or falls to maintain a constant air flow. Movement of the port controller assembly does not require the use of seals, diaphragms, tight tolerances, bushings, bearings, hinges, guides, or lubricants.

Controlled differential pressure system for an enhanced fluid blending apparatus

DOEpatents

Hallman, Jr., Russell Louis

2009-02-24

A system and method for producing a controlled blend of two or more fluids. Thermally-induced permeation through a permeable tube is used to mix a first fluid from outside the tube with a second fluid flowing through the tube. Mixture ratios may be controlled by adjusting the temperature of the first fluid or by adjusting the pressure drop through the permeable tube. The combination of a back pressure control valve and a differential regulator is used to control the output pressure of the blended fluid. The combination of the back pressure control valve and differential regulator provides superior flow control of the second dry gas. A valve manifold system may be used to mix multiple fluids, and to adjust the volume of blended fluid produced, and to further modify the mixture ratio.

MAP stability, design, and analysis

NASA Technical Reports Server (NTRS)

Ericsson-Jackson, A. J.; Andrews, S. F.; O'Donnell, J. R., Jr.; Markley, F. L.

1998-01-01

The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. The design and analysis of the MAP attitude control system (ACS) have been refined since work previously reported. The full spacecraft and instrument flexible model was developed in NASTRAN, and the resulting flexible modes were plotted and reduced with the Modal Significance Analysis Package (MSAP). The reduced-order model was used to perform the linear stability analysis for each control mode, the results of which are presented in this paper. Although MAP is going to a relatively disturbance-free Lissajous orbit around the Earth-Sun L(2) Lagrange point, a detailed disturbance-torque analysis is required because there are only a small number of opportunities for momentum unloading each year. Environmental torques, including solar pressure at L(2), aerodynamic and gravity gradient during phasing-loop orbits, were calculated and simulated. Thruster plume impingement torques that could affect the performance of the thruster modes were estimated and simulated, and a simple model of fuel slosh was derived to model its effect on the motion of the spacecraft. In addition, a thruster mode linear impulse controller was developed to meet the accuracy requirements of the phasing loop burns. A dynamic attitude error limiter was added to improve the performance of the ACS during large attitude slews. The result of this analysis is a stable ACS subsystem that meets all of the mission's requirements.

Hydrostatic pressure promotes the proliferation and osteogenic/chondrogenic differentiation of mesenchymal stem cells: The roles of RhoA and Rac1.

PubMed

Zhao, Yin-Hua; Lv, Xin; Liu, Yan-Li; Zhao, Ying; Li, Qiang; Chen, Yong-Jin; Zhang, Min

2015-05-01

Our previous studies have shown that hydrostatic pressure can serve as an active regulator for bone marrow mesenchymal stem cells (BMSCs). The current work further investigates the roles of cytoskeletal regulatory proteins Ras homolog gene family member A (RhoA) and Ras-related C3 botulinum toxin substrate 1 (Rac1) in hydrostatic pressure-related effects on BMSCs. Flow cytometry assays showed that the hydrostatic pressure promoted cell cycle initiation in a RhoA- and Rac1-dependent manner. Furthermore, fluorescence assays confirmed that RhoA played a positive and Rac1 displayed a negative role in the hydrostatic pressure-induced F-actin stress fiber assembly. Western blots suggested that RhoA and Rac1 play central roles in the pressure-inhibited ERK phosphorylation, and Rac1 but not RhoA was involved in the pressure-promoted JNK phosphorylation. Finally, real-time polymerase chain reaction (PCR) experiments showed that pressure promoted the expression of osteogenic marker genes in BMSCs at an early stage of osteogenic differentiation through the up-regulation of RhoA activity. Additionally, the PCR results showed that pressure enhanced the expression of chondrogenic marker genes in BMSCs during chondrogenic differentiation via the up-regulation of Rac1 activity. Collectively, our results suggested that RhoA and Rac1 are critical to the pressure-induced proliferation and differentiation, the stress fiber assembly, and MAPK activation in BMSCs. Copyright © 2015. Published by Elsevier B.V.

Design of Novel FBG-Based Sensor of Differential Pressure with Magnetic Transfer.

PubMed

Lyu, Guohui; Che, Guohang; Li, Junqing; Jiang, Xu; Wang, Keda; Han, Yueqiang; Gao, Laixu

2017-02-15

In this paper, a differential pressure sensor with magnetic transfer is proposed, in which the non-electric measurement based on the fiber Bragg grating (FBG) with the position limiting mechanism is implemented without the direct contact of the sensing unit with the measuring fluid. The test shows that the designed sensor is effective for measuring differential pressure in the range of 0~10 kPa with a sensitivity of 0.0112 nm/kPa, which can be used in environments with high temperature, strong corrosion and high overload measurements.

A new barometer from stress fields around inclusions

NASA Astrophysics Data System (ADS)

Avadanii, Diana; Hansen, Lars; Wallis, David; Waters, David

2017-04-01

A key step in understanding geological and geodynamic processes is modelling the pressure-temperature paths of metamorphic rocks. Traditional thermobarometry relies on mineral assemblage equilibria and thermodynamic modelling to infer the pressures and temperatures of chemical equilibration. This approach requires the presence of specific mineral assemblages and compositions, which narrows its applicability. In this study we aim to develop a geobarometer based on mechanical interactions between inclusions and their host grains. Exhumation of minerals with inclusions causes heterogeneous residual stress fields due to the different, and often anisotropic, elastic properties of the inclusion and host. Recent studies measure residual mean stresses within inclusions using Raman spectroscopy and use those stresses as a barometer. In contrast, we map each component of the stress tensor around inclusions using high angular-resolution electron backscatter diffraction (HR-EBSD). This technique provides both higher spatial resolution and increased sensitivity to elastic strains relative to Raman spectroscopy. We focus on quartz inclusions in garnet, a common feature in metamorphic rocks. This assemblage also provides an opportunity to test our results with compositional thermobarometry. We analyse samples metamorphosed at pressures ranging from ˜ 300 MPa to ˜ 1600 MPa, as recorded by independent geobarometers. HR-EBSD reveals symmetric and lobate signals around inclusions, with elastic strains and residual stresses of the order 10-3 and ±102 -103 MPa, respectively. We solve Eshelby's problem for the 'inhomogeneous inclusion' case to simulate the elastic strain/stress field around an anisotropic ellipsoidal inclusion surrounded by an isotropic, homogeneous, infinite matrix. This model calculates the stress disturbances caused by differential expansion of an inclusion and host subjected to decompression. We additionally account for differential expansion related to cooling by imposing an eigenstrain in the inclusion, according to the thermal expansivity of quartz. Thermal contraction in the host garnet is accounted for by modifying the macroscopic pressure. The simulations reproduce the general pattern of the elastic fields that we observe from HR-EBSD and account for different geometries of the inclusion. The simulations provide the basis for quantitatively relating the stress fields measured by HR-EBSD to the entrapment pressures of inclusions.

The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

PubMed Central

Pisano, Dominic V.; Niesten, Marlien E.F.; Merchant, Saumil N.; Nakajima, Hideko Heidi

2013-01-01

Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) enable quantification of the differential pressure across the cochlear partition, the stimulus that excites the cochlear partition. We used intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure were measured simultaneously for various sizes of SCD followed by SCD patching. Our results showed that at low frequencies (<600 Hz), SCD decreased the pressure in both SV and ST, as well as differential pressure, and these effects became more pronounced as dehiscence size was increased. Near 100 Hz, SV decreased about 10 dB for a 0.5 mm dehiscence and 20 dB for a 2 mm dehiscence, while ST decreased about 8 dB for a 0.5 mm dehiscence and 18 dB for a 2mm dehiscence. Differential pressure decreased about 10 dB for a 0.5 mm dehiscence and about 20 dB for a 2 mm dehiscense at 100 Hz. In some ears, for frequencies above 1 kHz, the smallest pinpoint dehiscence had bigger effects on the differential pressure (10 dB decrease) than larger dehiscenses (less than 10 dB decrease), suggesting larger hearing losses in this frequency range. These effects due to SCD were reversible by patching the dehiscence. We also showed that under certain circumstances such as SCD, stapes velocity is not related to how the ear can transduce sound across the cochlear partition because it is not directly related to the differential pressure, emphasizing that certain pathologies cannot be fully assessed by measurements such as stapes velocity. PMID:22814034

A program to evaluate a control system based on feedback of aerodynamic pressure differentials, part 1

NASA Technical Reports Server (NTRS)

Hrabak, R. R.; Levy, D. W.; Finn, P.; Roskam, J.

1981-01-01

The use of pressure differentials in a flight control system was evaluated. The pressure profile around the test surface was determined using two techniques: (1) windtunnel data (actual); and (2) NASA/Langley Single Element Airfoil Computer Program (theoretical). The system designed to evaluate the concept of using pressure differentials is composed of a sensor drive and power amplifiers, actuator, position potentiometer, and a control surface. The characteristics (both desired and actual) of the system and each individual component were analyzed. The desired characteristics of the system as a whole are given. The flight control system developed, the testing procedures and data reduction methods used, and theoretical frequency response analysis are described.

Synchrotron radiation based STXM analysis and micro-XRF mapping of differential expression of extracellular thiol groups by Acidithiobacillus ferrooxidans grown on Fe(2+) and S(0).

PubMed

Xia, Jin-Lan; Liu, Hong-Chang; Nie, Zhen-Yuan; Peng, An-An; Zhen, Xiang-Jun; Yang, Yun; Zhang, Xiu-Li

2013-09-01

The differential expression of extracellular thiol groups by Acidithiobacillus ferrooxidans grown on substrates Fe(2+) and S(0) was investigated by using synchrotron radiation based scanning transmission X-ray microscopy (STXM) imaging and microbeam X-ray fluorescence (μ-XRF) mapping. The extracellular thiol groups (SH) were first alkylated by iodoacetic acid forming Protein-SCH2COOH and then the P-SCH2COOH was marked by calcium ions forming P-SCH2COOCa. The STXM imaging and μ-XRF mapping of SH were based on analysis of SCH2COO-bonded Ca(2+). The results indicated that the thiol group content of A. ferrooxidans grown on S(0) is 3.88 times to that on Fe(2+). Combined with selective labeling of SH by Ca(2+), the STXM imaging and μ-XRF mapping provided an in situ and rapid analysis of differential expression of extracellular thiol groups. © 2013.

Development of a high temperature capacitive pressure transducer

NASA Technical Reports Server (NTRS)

Egger, R. L.

1977-01-01

High temperature pressure transducers capable of continuous operation while exposed to 650 C were developed and evaluated over a full-scale differential pressure range of + or - 69 kPa. The design of the pressure transducers was based on the use of a diaphragm to respond to pressure, variable capacitive elements arranged to operate as a differential capacitor to measure diaphragm response and on the use of fused silica for the diaphragm and its supporting assembly. The uncertainty associated with measuring + or - 69 kPa pressures between 20C and 650C was less than + or - 6%.

Haemodynamic changes during neck pressure and suction in seated and supine positions

NASA Technical Reports Server (NTRS)

Ogoh, S.; Fadel, P. J.; Monteiro, F.; Wasmund, W. L.; Raven, P. B.

2002-01-01

We sought to quantify the contribution of cardiac output (Q) and total vascular conductance (TVC) to carotid baroreflex-mediated changes in mean arterial pressure (MAP) in the upright seated and supine positions. Acute changes in carotid sinus transmural pressure were evoked using brief 5 s pulses of neck pressure and neck suction (NP/NS) via a simplified paired neck chamber that was developed to enable beat-to-beat measurements of stroke volume using pulse-doppler ultrasound. Percentage contributions of Q and TVC were achieved by calculating the predicted change in MAP during carotid baroreflex stimulation if only the individual changes in Q or TVC occurred and all other parameters remained at control values. All NP and NS stimuli from +40 to -80 Torr (+5.33 to -10.67 kPa) induced significant changes in Q and TVC in both the upright seated and supine positions (P < 0.001). Cardiopulmonary baroreceptor loading with the supine position appeared to cause a greater reliance on carotid baroreflex-mediated changes in Q. Nevertheless, in both the seated and supine positions the changes in MAP were primarily mediated by alterations in TVC (percentage contribution of TVC at the time-of-peak MAP, seated 95 +/- 13, supine 76 +/- 17 %). These data indicate that alterations in vasomotor activity are the primary means by which the carotid baroreflex regulates blood pressure during acute changes in carotid sinus transmural pressure.

Racial differences in the impact of social support on nocturnal blood pressure.

PubMed

Cooper, Denise C; Ziegler, Michael G; Nelesen, Richard A; Dimsdale, Joel E

2009-06-01

To investigate whether black and white adults benefit similarly from perceived social support in relation to blood pressure (BP) dipping during sleep. The Interpersonal Support Evaluation List (ISEL, 12-item version), which measures the perceived availability of several types of functional social support, was examined for interactive effects with race on dipping of mean arterial pressure (MAP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) derived from 24-hour ambulatory blood pressure monitoring (ABPM). The sample consisted of 156 young to middle-aged adults (61 blacks, 95 whites; mean age = 35.7 years). Mean ISEL scores did not differ between racial groups. Controlling for age, body mass index (BMI), resting BP, and socioeconomic status (SES), the interaction of social support by race yielded associations with nighttime dipping in MAP and DBP (p < .001) as well as SBP (p < .01). As ISEL scores increased among white participants, the extent of dipping increased in MAP, SBP, and DBP (p < .01), explaining 10%, 10%, and 8% of the variance, respectively. Conversely, black participants exhibited associations between increasing ISEL scores and decreasing levels of dipping in MAP, SBP, and DBP (p < .05), accounting for 9%, 8%, and 8% of the variance, respectively. As perceived social support increased, white adults received cardiovascular benefits as suggested by enhanced nocturnal dipping of BP, but black adults accrued risks as evidenced by blunted declines in BP during sleep.

Factors influencing delivered mean airway pressure during nasal CPAP with the RAM cannula.

PubMed

Gerdes, Jeffrey S; Sivieri, Emidio M; Abbasi, Soraya

2016-01-01

To measure mean airway pressure (MAP) delivered through the RAM Cannula® when used with a ventilator in CPAP mode as a function of percent nares occlusion in a simulated nasal interface/test lung model and to compare the results to MAPs using a nasal continuous positive airway pressure (NCPAP) interface with nares fully occluded. An artificial airway model was connected to a spontaneous breathing lung model in which MAP was measured at set NCPAP levels between 4 and 8 cmH2 O provided by a Dräger Evita XL® ventilator and delivered through three sizes of RAM cannulae. Measurements were performed with varying leakage at the nasal interface by decreasing occlusion from 100% to 29%, half-way prong insertion, and simulated mouth leakage. Comparison measurements were made using the Dräger BabyFlow® NCPAP interface with a full nasal seal. With simulated mouth closed, the Dräger interface delivered MAPs within 0.5 cmH2 O of set CPAP levels. For the RAM cannula, with 60-80% nares occlusion, overall delivered MAPs were 60 ± 17% less than set CPAP levels (P < 0.001). Further, MAP decreased progressively with decreasing percent nares occlusion. The simulated open mouth condition resulted in significantly lower MAPs to <1.7 cmH2 O. The one-half prong insertion depth condition, with closed mouth, yielded MAPs approximately 35 ± 9% less than full insertion pressures (P < 0.001). In our bench tests, the RAM interface connected to a ventilator in NCPAP mode failed to deliver set CPAP levels when applied using the manufacturer recommended 60-80% nares occlusion, even with closed mouth and full nasal prong insertion conditions. © 2015 Wiley Periodicals, Inc.

Temporally inter-comparable maps of terrestrial wilderness and the Last of the Wild

NASA Astrophysics Data System (ADS)

Allan, James R.; Venter, Oscar; Watson, James E. M.

2017-12-01

Wilderness areas, defined as areas free of industrial scale activities and other human pressures which result in significant biophysical disturbance, are important for biodiversity conservation and sustaining the key ecological processes underpinning planetary life-support systems. Despite their importance, wilderness areas are being rapidly eroded in extent and fragmented. Here we present the most up-to-date temporally inter-comparable maps of global terrestrial wilderness areas, which are essential for monitoring changes in their extent, and for proactively planning conservation interventions to ensure their preservation. Using maps of human pressure on the natural environment for 1993 and 2009, we identified wilderness as all 'pressure free' lands with a contiguous area >10,000 km2. These places are likely operating in a natural state and represent the most intact habitats globally. We then created a regionally representative map of wilderness following the well-established 'Last of the Wild' methodology; which identifies the 10% area with the lowest human pressure within each of Earth's 60 biogeographic realms, and identifies the ten largest contiguous areas, along with all contiguous areas >10,000 km2.

System Would Regulate Low Gas Pressure

NASA Technical Reports Server (NTRS)

Frazer, Robert E.

1994-01-01

System intended to maintain gases in containers at pressures near atmospheric. Includes ballast volume in form of underinflated balloon that communicates with working volume. Balloon housed in rigid chamber not subjected to extremes of temperature of working volume. Pressure in chamber surrounding balloon regulated at ambient atmospheric pressure or at constant small differential pressure above or below ambient. Expansion and contraction of balloon accommodates expansion or contraction of gas during operational heating or cooling in working volume, maintaining pressure in working volume at ambient or constant differential above or below ambient. Gas lost from system due to leakage or diffusion, low-pressure sensor responds, signaling valve actuators to supply more gas to working volume. If pressure rises too high, overpressure relief valve opens before excessive pressure damages system.

Perioperative optimal blood pressure as determined by ultrasound tagged near infrared spectroscopy and its association with postoperative acute kidney injury in cardiac surgery patients.

PubMed

Hori, Daijiro; Hogue, Charles; Adachi, Hideo; Max, Laura; Price, Joel; Sciortino, Christopher; Zehr, Kenton; Conte, John; Cameron, Duke; Mandal, Kaushik

2016-04-01

Perioperative blood pressure management by targeting individualized optimal blood pressure, determined by cerebral blood flow autoregulation monitoring, may ensure sufficient renal perfusion. The purpose of this study was to evaluate changes in the optimal blood pressure for individual patients, determined during cardiopulmonary bypass (CPB) and during early postoperative period in intensive care unit (ICU). A secondary aim was to examine if excursions below optimal blood pressure in the ICU are associated with risk of cardiac surgery-associated acute kidney injury (CSA-AKI). One hundred and ten patients undergoing cardiac surgery had cerebral blood flow monitored with a novel technology using ultrasound tagged near infrared spectroscopy (UT-NIRS) during CPB and in the first 3 h after surgery in the ICU. The correlation flow index (CFx) was calculated as a moving, linear correlation coefficient between cerebral flow index measured using UT-NIRS and mean arterial pressure (MAP). Optimal blood pressure was defined as the MAP with the lowest CFx. Changes in optimal blood pressure in the perioperative period were observed and the association of blood pressure excursions (magnitude and duration) below the optimal blood pressure [area under the curve (AUC) < OptMAP mmHgxh] with incidence of CSA-AKI (defined using Kidney Disease: Improving Global Outcomes criteria) was examined. Optimal blood pressure during early ICU stay and CPB was correlated (r = 0.46, P < 0.0001), but was significantly higher in the ICU compared with during CPB (75 ± 8.7 vs 71 ± 10.3 mmHg, P = 0.0002). Thirty patients (27.3%) developed CSA-AKI within 48 h after the surgery. AUC < OptMAP was associated with CSA-AKI during CPB [median, 13.27 mmHgxh, interquartile range (IQR), 4.63-20.14 vs median, 6.05 mmHgxh, IQR 3.03-12.40, P = 0.008], and in the ICU (13.72 mmHgxh, IQR 5.09-25.54 vs 5.65 mmHgxh, IQR 1.71-13.07, P = 0.022). Optimal blood pressure during CPB and in the ICU was correlated. Excursions below optimal blood pressure (AUC < OptMAP mmHgXh) during perioperative period are associated with CSA-AKI. Individualized blood pressure management based on cerebral autoregulation monitoring during the perioperative period may help improve CSA-AKI-related outcomes. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Perioperative optimal blood pressure as determined by ultrasound tagged near infrared spectroscopy and its association with postoperative acute kidney injury in cardiac surgery patients

PubMed Central

Hori, Daijiro; Hogue, Charles; Adachi, Hideo; Max, Laura; Price, Joel; Sciortino, Christopher; Zehr, Kenton; Conte, John; Cameron, Duke; Mandal, Kaushik

2016-01-01

OBJECTIVES Perioperative blood pressure management by targeting individualized optimal blood pressure, determined by cerebral blood flow autoregulation monitoring, may ensure sufficient renal perfusion. The purpose of this study was to evaluate changes in the optimal blood pressure for individual patients, determined during cardiopulmonary bypass (CPB) and during early postoperative period in intensive care unit (ICU). A secondary aim was to examine if excursions below optimal blood pressure in the ICU are associated with risk of cardiac surgery-associated acute kidney injury (CSA-AKI). METHODS One hundred and ten patients undergoing cardiac surgery had cerebral blood flow monitored with a novel technology using ultrasound tagged near infrared spectroscopy (UT-NIRS) during CPB and in the first 3 h after surgery in the ICU. The correlation flow index (CFx) was calculated as a moving, linear correlation coefficient between cerebral flow index measured using UT-NIRS and mean arterial pressure (MAP). Optimal blood pressure was defined as the MAP with the lowest CFx. Changes in optimal blood pressure in the perioperative period were observed and the association of blood pressure excursions (magnitude and duration) below the optimal blood pressure [area under the curve (AUC) < OptMAP mmHgxh] with incidence of CSA-AKI (defined using Kidney Disease: Improving Global Outcomes criteria) was examined. RESULTS Optimal blood pressure during early ICU stay and CPB was correlated (r = 0.46, P < 0.0001), but was significantly higher in the ICU compared with during CPB (75 ± 8.7 vs 71 ± 10.3 mmHg, P = 0.0002). Thirty patients (27.3%) developed CSA-AKI within 48 h after the surgery. AUC < OptMAP was associated with CSA-AKI during CPB [median, 13.27 mmHgxh, interquartile range (IQR), 4.63–20.14 vs median, 6.05 mmHgxh, IQR 3.03–12.40, P = 0.008], and in the ICU (13.72 mmHgxh, IQR 5.09–25.54 vs 5.65 mmHgxh, IQR 1.71–13.07, P = 0.022). CONCLUSIONS Optimal blood pressure during CPB and in the ICU was correlated. Excursions below optimal blood pressure (AUC < OptMAP mmHgXh) during perioperative period are associated with CSA-AKI. Individualized blood pressure management based on cerebral autoregulation monitoring during the perioperative period may help improve CSA-AKI-related outcomes. PMID:26763042

Impaired cerebral autoregulation and brain injury in newborns with hypoxic-ischemic encephalopathy treated with hypothermia.

PubMed

Massaro, An N; Govindan, R B; Vezina, Gilbert; Chang, Taeun; Andescavage, Nickie N; Wang, Yunfei; Al-Shargabi, Tareq; Metzler, Marina; Harris, Kari; du Plessis, Adre J

2015-08-01

Impaired cerebral autoregulation may contribute to secondary injury in newborns with hypoxic-ischemic encephalopathy (HIE). Continuous, noninvasive assessment of cerebral pressure autoregulation can be achieved with bedside near-infrared spectroscopy (NIRS) and systemic mean arterial blood pressure (MAP) monitoring. This study aimed to evaluate whether impaired cerebral autoregulation measured by NIRS-MAP monitoring during therapeutic hypothermia and rewarming relates to outcome in 36 newborns with HIE. Spectral coherence analysis between NIRS and MAP was used to quantify changes in the duration [pressure passivity index (PPI)] and magnitude (gain) of cerebral autoregulatory impairment. Higher PPI in both cerebral hemispheres and gain in the right hemisphere were associated with neonatal adverse outcomes [death or detectable brain injury by magnetic resonance imaging (MRI), P < 0.001]. NIRS-MAP monitoring of cerebral autoregulation can provide an ongoing physiological biomarker that may help direct care in perinatal brain injury. Copyright © 2015 the American Physiological Society.

Halo Pressure Profile through the Skew Cross-power Spectrum of the Sunyaev–Zel’dovich Effect and CMB Lensing in Planck

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

Timmons, Nicholas; Cooray, Asantha; Feng, Chang

2017-11-01

We measure the cosmic microwave background (CMB) skewness power spectrum in Planck , using frequency maps of the HFI instrument and the Sunyaev–Zel’dovich (SZ) component map. The two-to-one skewness power spectrum measures the cross-correlation between CMB lensing and the thermal SZ effect. We also directly measure the same cross-correlation using the Planck CMB lensing map and the SZ map and compare it to the cross-correlation derived from the skewness power spectrum. We model fit the SZ power spectrum and CMB lensing–SZ cross-power spectrum via the skewness power spectrum to constrain the gas pressure profile of dark matter halos. The gasmore » pressure profile is compared to existing measurements in the literature including a direct estimate based on the stacking of SZ clusters in Planck .« less

A transmission-line model of back-cavity dynamics for in-plane pressure-differential microphones.

PubMed

Kim, Donghwan; Kuntzman, Michael L; Hall, Neal A

2014-11-01

Pressure-differential microphones inspired by the hearing mechanism of a special parasitoid fly have been described previously. The designs employ a beam structure that rotates about two pivots over an enclosed back volume. The back volume is only partially enclosed due to open slits around the perimeter of the beam. The open slits enable incoming sound waves to affect the pressure profile in the microphone's back volume. The goal of this work is to study the net moment applied to pressure-differential microphones by an incoming sound wave, which in-turn requires modeling the acoustic pressure distribution within the back volume. A lumped-element distributed transmission-line model of the back volume is introduced for this purpose. It is discovered that the net applied moment follows a low-pass filter behavior such that, at frequencies below a corner frequency depending on geometrical parameters of the design, the applied moment is unaffected by the open slits. This is in contrast to the high-pass filter behavior introduced by barometric pressure vents in conventional omnidirectional microphones. The model accurately predicts observed curvature in the frequency response of a prototype pressure-differential microphone 2 mm × 1 mm × 0.5 mm in size and employing piezoelectric readout.

Evaluation of indirect blood pressure monitoring in awake and anesthetized red-tailed hawks (Buteo jamaicensis): effects of cuff size, cuff placement, and monitoring equipment.

PubMed

Zehnder, Ashley M; Hawkins, Michelle G; Pascoe, Peter J; Kass, Philip H

2009-09-01

To compare Doppler and oscillometric methods of indirect arterial blood pressure (IBP) with direct arterial measurements in anesthetized and awake red-tailed hawks. Prospective, randomized, blinded study. Six, sex unknown, adult red-tailed hawks. Birds were anesthetized and IBP measurements were obtained by oscillometry (IBP-O) and Doppler (IBP-D) on the pectoral and pelvic limbs using three cuffs of different width based on limb circumference: cuff 1 (20-30% of circumference), cuff 2 (30-40%), and cuff 3 (40-50%). Direct arterial pressure measurements were obtained from the contralateral superficial ulnar artery. Indirect blood pressure measurements were compared to direct systolic arterial pressure (SAP) and mean arterial pressure (MAP) during normotension and induced states of hypotension and hypertension. Measurements were also obtained in awake, restrained birds. Three-way anova, linear regression and Bland-Altman analyses were used to evaluate the IBP-D data. Results are reported as mean bias (95% confidence intervals). The IBP-O monitor reported errors during 54% of the measurements. Indirect blood pressure Doppler measurements were most accurate with cuff 3 and were comparable to MAP with a bias of 2 (-9, 13 mmHg). However, this cuff consistently underestimated SAP with a bias of 33 (19, 48 mmHg). Variability in the readings within and among birds was high. There was no significant difference between sites of cuff placement. Awake birds had SAP, MAP and diastolic arterial pressure that were 56, 43, and 38 mmHg higher than anesthetized birds. Indirect blood pressure (oscillometric) measurements were unreliable in red-tailed hawks. Indirect blood pressure (Doppler) measurements were closer to MAP measurements than SAP measurements. There was slightly better agreement with the use of cuff 3 on either the pectoral or pelvic limbs. Awake, restrained birds have significantly higher arterial pressures than those under sevoflurane anesthesia.

Evidence for different origin of sex chromosomes in snakes, birds, and mammals and step-wise differentiation of snake sex chromosomes

PubMed Central

Matsubara, Kazumi; Tarui, Hiroshi; Toriba, Michihisa; Yamada, Kazuhiko; Nishida-Umehara, Chizuko; Agata, Kiyokazu; Matsuda, Yoichi

2006-01-01

All snake species exhibit genetic sex determination with the ZZ/ZW type of sex chromosomes. To investigate the origin and evolution of snake sex chromosomes, we constructed, by FISH, a cytogenetic map of the Japanese four-striped rat snake (Elaphe quadrivirgata) with 109 cDNA clones. Eleven of the 109 clones were localized to the Z chromosome. All human and chicken homologues of the snake Z-linked genes were located on autosomes, suggesting that the sex chromosomes of snakes, mammals, and birds were all derived from different autosomal pairs of the common ancestor. We mapped the 11 Z-linked genes of E. quadrivirgata to chromosomes of two other species, the Burmese python (Python molurus bivittatus) and the habu (Trimeresurus flavoviridis), to investigate the process of W chromosome differentiation. All and 3 of the 11 clones were localized to both the Z and W chromosomes in P. molurus and E. quadrivirgata, respectively, whereas no cDNA clones were mapped to the W chromosome in T. flavoviridis. Comparative mapping revealed that the sex chromosomes are only slightly differentiated in P. molurus, whereas they are fully differentiated in T. flavoviridis, and E. quadrivirgata is at a transitional stage of sex-chromosome differentiation. The differentiation of sex chromosomes was probably initiated from the distal region on the short arm of the protosex chromosome of the common ancestor, and then deletion and heterochromatization progressed on the sex-specific chromosome from the phylogenetically primitive boids to the more advanced viperids. PMID:17110446

CYP3A4 and CYP3A5 polymorphisms and blood pressure response to amlodipine among African-American men and women with early hypertensive renal disease.

PubMed

Bhatnagar, Vibha; Garcia, Erin P; O'Connor, Daniel T; Brophy, Victoria H; Alcaraz, John; Richard, Erin; Bakris, George L; Middleton, John P; Norris, Keith C; Wright, Jackson; Hiremath, Leena; Contreras, Gabriel; Appel, Lawrence J; Lipkowitz, Michael S

2010-01-01

To explore the association between CYP3A4 and CYP3A5 gene polymorphisms and blood pressure response to amlodipine among participants from the African-American Study of Kidney Disease and Hypertension Trial randomized to amlodipine (n = 164). Cox proportional hazards models were used to determine the risk of reaching a target mean arterial pressure (MAP) of < or =107 mm Hg by CYP3A4 (A-392G and T16090C) and CYP3A5 (A6986G) gene polymorphisms, stratified by MAP randomization group (low or usual) and controlling for other predictors for blood pressure response. Women randomized to a usual MAP goal with an A allele at CYP3A4 A-392G were more likely to reach a target MAP of 107 mm Hg. The adjusted hazard ratio (AA/AG compared to GG) with 95% confidence interval was 3.41 (1.20-9.64; p = 0.020). Among participants randomized to a lower MAP goal, those with the C allele at CYP3A4 T16090C were more likely to reach target MAP: The adjusted hazard ratio was 2.04 (1.17-3.56; p = 0.010). After adjustment for multiple testing using a threshold significance level of p = 0.016, only the CYP3A4 T16090C SNP remained significant. CYP3A5 A6986G was not associated with blood pressure response. Our findings suggest that blood pressure response to amlodipine among high-risk African-Americans appears to be determined by CYP3A4 genotypes, and sex specificity may be an important consideration. Clinical applications of CYP3A4 genotype testing for individualized treatment regimens warrant further study. Copyright (c) 2009 S. Karger AG, Basel.

CYP3A4 and CYP3A5 Polymorphisms and Blood Pressure Response to Amlodipine among African-American Men and Women with Early Hypertensive Renal Disease

PubMed Central

Bhatnagar, Vibha; Garcia, Erin P.; O’Connor, Daniel T.; Brophy, Victoria H.; Alcaraz, John; Richard, Erin; Bakris, George L.; Middleton, John P.; Norris, Keith C.; Wright, Jackson; Hiremath, Leena; Contreras, Gabriel; Appel, Lawrence J.; Lipkowitz, Michael S.

2010-01-01

Purpose To explore the association between CYP3A4 and CYP3A5 gene polymorphisms and blood pressure response to amlodipine among participants from the African-American Study of Kidney Disease and Hypertension Trial randomized to amlodipine (n = 164). Methods Cox proportional hazards models were used to determine the risk of reaching a target mean arterial pressure (MAP) of ≤107 mm Hg by CYP3A4 (A–392G and T16090C) and CYP3A5 (A6986G) gene polymorphisms, stratified by MAP randomization group (low or usual) and controlling for other predictors for blood pressure response. Results Women randomized to a usual MAP goal with an A allele at CYP3A4 A–392G were more likely to reach a target MAP of 107 mm Hg. The adjusted hazard ratio (AA/AG compared to GG) with 95% confidence interval was 3.41 (1.20–9.64; p = 0.020). Among participants randomized to a lower MAP goal, those with the C allele at CYP3A4 T16090C were more likely to reach target MAP: The adjusted hazard ratio was 2.04 (1.17–3.56; p = 0.010). After adjustment for multiple testing using a threshold significance level of p = 0.016, only the CYP3A4 T16090C SNP remained significant. CYP3A5 A6986G was not associated with blood pressure response. Conclusions Our findings suggest that blood pressure response to amlodipine among high-risk African-Americans appears to be determined by CYP3A4 genotypes, and sex specificity may be an important consideration. Clinical applications of CYP3A4 genotype testing for individualized treatment regimens warrant further study. PMID:19907160

One-stage free-vortex aerodynamic window with pressure ratio 100 and atmospheric exhaust

NASA Astrophysics Data System (ADS)

Malkov, Victor M.; Trilis, A. V.; Savin, Andrew V.; Druzhinin, S. L.

2005-03-01

The aerodynamic windows (AW) are intended for a high power extraction from the gas laser optical cavity, where the pressure is much lower than environment pressure. The main requirements for the aerodynamic windows are to satisfy a low level of optical disturbances in a laser beam extraction channel and an air leakage absence into the optical cavity. Free vortex AW are most economic from a point of working gas consumption and the greatest pressure differential is realized on them at an exhaust to atmosphere. For ideal gas it is possible to receive as much as large pressure differential, however for real gas a pressure differential more than P>=50 is difficult to achieve. To achieve the pressure ratio 100 in free vortex single-stage AW the method of stabilizing of boundary layer was used. The gas of curtain was decelerated in the diffuser and was exhausted into the atmosphere straightly. The pressure recovery improvement was achieved by using the boundary layer blowing inside the diffuser. Only 10% of total mass flow was used for boundary layer blowing.

Application of Zen sitting principles to microscopic surgery seating.

PubMed

Noro, Kageyu; Naruse, Tetsuya; Lueder, Rani; Nao-I, Nobuhisa; Kozawa, Maki

2012-03-01

This paper describes the application of an alternative seating concept for surgeons that reflects the research of Zen sitting postures, which require Zazen meditators to maintain fixed postures for long durations. The aim of this alternative approach is to provide sitters with a seat pan with sacral support(1) that provides a more even distribution of seat pressures, induces forward pelvic rotation and improves lumbar, buttock and thigh support. This approach was applied to the development of a chair for microscopic surgery. The experimental chair is a seat pan that closely matches the three-dimensional contours of the user's buttocks. Seat comfort was evaluated by comparing both changes in pelvic tilt and seat pressure distributions using Regionally-Differentiated Pressure Maps (RDPM) with subjective ratings of surgeons while operating in prototype and conventional chairs. Findings include that the sacral support of the prototype chair prevents backward pelvic rotation, as seen in zazen (Zen sitting postures). Preliminary data suggests that the prototype provided greater sitting comfort and support for constrained operating postures than did the conventional chair. These findings support the selective application of concave-shaped seat pans that conform to users' buttocks and reflect Zen sitting principles. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Using Concept Mapping to Improve Poor Readers' Understanding of Expository Text

ERIC Educational Resources Information Center

Morfidi, Eleni; Mikropoulos, Anastasios; Rogdaki, Aspasia

2018-01-01

The present study examined whether the use of concept mapping is more effective in teaching expository material in comparison to a traditional, lecture only, approach. Its objective was threefold. First, to determine if multimedia concept mapping produces differential learning outcomes compared to digital text-based concept mapping. Secondly, to…

Respiratory sinus arrhythmia: opposite effects on systolic and mean arterial pressure in supine humans

NASA Technical Reports Server (NTRS)

Elstad, M.; Toska, K.; Chon, K. H.; Raeder, E. A.; Cohen, R. J.

2001-01-01

1. Are arterial blood pressure fluctuations buffered or reinforced by respiratory sinus arrhythmia (RSA)? There is still considerable debate about this simple question. Different results have been obtained, triggering a discussion as to whether or not the baroreflexes are responsible for RSA. We suspected that the measurements of different aspects of arterial pressure (mean arterial pressure (MAP) and systolic pressure (SP)) can explain the conflicting results. 2. Simultaneous recordings of beat-to-beat MAP, SP, left cardiac stroke volume (SV, pulsed ultrasound Doppler), heart rate (HR) and respiration (RE) were obtained in 10 healthy young adults during spontaneous respiration. In order to eliminate HR variations at respiratory frequency we used propranolol and atropine administration in the supine and tilted positions. Respiration-synchronous variation in the recorded variables was quantified by spectral analysis of the recordings of each of these variables, and the phase relations between them were determined by cross-spectral analysis. 3. MAP fluctuations increased after removing heart rate variations in both supine and tilted position, whereas SP fluctuations decreased in the supine position and increased in the head-up tilted position. 4. RSA buffers respiration-synchronous fluctuations in MAP in both positions. However, fluctuations in SP were reinforced by RSA in the supine and buffered in the tilted position.

Diffusion maps for high-dimensional single-cell analysis of differentiation data.

PubMed

Haghverdi, Laleh; Buettner, Florian; Theis, Fabian J

2015-09-15

Single-cell technologies have recently gained popularity in cellular differentiation studies regarding their ability to resolve potential heterogeneities in cell populations. Analyzing such high-dimensional single-cell data has its own statistical and computational challenges. Popular multivariate approaches are based on data normalization, followed by dimension reduction and clustering to identify subgroups. However, in the case of cellular differentiation, we would not expect clear clusters to be present but instead expect the cells to follow continuous branching lineages. Here, we propose the use of diffusion maps to deal with the problem of defining differentiation trajectories. We adapt this method to single-cell data by adequate choice of kernel width and inclusion of uncertainties or missing measurement values, which enables the establishment of a pseudotemporal ordering of single cells in a high-dimensional gene expression space. We expect this output to reflect cell differentiation trajectories, where the data originates from intrinsic diffusion-like dynamics. Starting from a pluripotent stage, cells move smoothly within the transcriptional landscape towards more differentiated states with some stochasticity along their path. We demonstrate the robustness of our method with respect to extrinsic noise (e.g. measurement noise) and sampling density heterogeneities on simulated toy data as well as two single-cell quantitative polymerase chain reaction datasets (i.e. mouse haematopoietic stem cells and mouse embryonic stem cells) and an RNA-Seq data of human pre-implantation embryos. We show that diffusion maps perform considerably better than Principal Component Analysis and are advantageous over other techniques for non-linear dimension reduction such as t-distributed Stochastic Neighbour Embedding for preserving the global structures and pseudotemporal ordering of cells. The Matlab implementation of diffusion maps for single-cell data is available at https://www.helmholtz-muenchen.de/icb/single-cell-diffusion-map. fbuettner.phys@gmail.com, fabian.theis@helmholtz-muenchen.de Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The importance of valve alignment in determining the pressure/flow characteristics of differential pressure shunt valves with anti-gravity devices.

PubMed

Francel, P C; Stevens, F A; Tompkins, P; Pollay, M

2001-02-01

The proper functioning of shunt valves in vivo is dependent on many factors, including the valve itself, the anti-siphon device or ASD (if included), patency of inlet and outlet tubing, and location of the valve. One important, but sometimes overlooked, consideration in valve function is the valve location relative to the tip of the ventricular inlet catheter. As with any pressure measurement, the zero or reference position is an important concept. In the case of shunt valves, the position of the proximal inlet catheter tip is fixed and therefore serves as the reference point for all pressure measurements. This study was conducted to document the importance of this relationship for the pressure/flow characteristics of the shunt valve. We bench-tested differential pressure valves (with integral anti-gravity devices; AGDs) from three manufacturers. Valves were connected to an "infinite" reservoir, and the starting head pressure for each was determined from product inserts. The inlet catheter tip was fixed at this position, and the valve body was moved in relation to the inlet catheter tip. Outflow rates were determined gravimetrically for positions varying between 4 cm above and 8 cm below the inlet catheter tip. All differential pressure valves utilized in this study that contained AGDs showed significant increases in outflow rate as the valve body was moved incrementally below the level of the inlet catheter tip. To allow functioning as a zero-hydrostatic pressure differential pressure valve, the AGD and the inlet catheter tip should be aligned at the same horizontal level.

Wavelet analysis of polarization maps of polycrystalline biological fluids networks

NASA Astrophysics Data System (ADS)

Ushenko, Y. A.

2011-12-01

The optical model of human joints synovial fluid is proposed. The statistic (statistic moments), correlation (autocorrelation function) and self-similar (Log-Log dependencies of power spectrum) structure of polarization two-dimensional distributions (polarization maps) of synovial fluid has been analyzed. It has been shown that differentiation of polarization maps of joint synovial fluid with different physiological state samples is expected of scale-discriminative analysis. To mark out of small-scale domain structure of synovial fluid polarization maps, the wavelet analysis has been used. The set of parameters, which characterize statistic, correlation and self-similar structure of wavelet coefficients' distributions of different scales of polarization domains for diagnostics and differentiation of polycrystalline network transformation connected with the pathological processes, has been determined.

Miniaturized pressurization system

DOEpatents

Whitehead, John C.; Swink, Don G.

1991-01-01

The invention uses a fluid stored at a low pressure and provides the fluid at a high pressure. The invention allows the low pressure fluid to flow to a fluid bore of a differential pump and from the pump to a fluid pressure regulator. After flowing through the regulator the fluid is converted to a gas which is directed to a gas bore of the differential pump. By controlling the flow of gas entering and being exhausted from the gas bore, the invention provides pressure to the fluid. By setting the regulator, the high pressure fluid can be set at predetermined values. Because the invention only needs a low pressure fluid, the inventive apparatus has a low mass, and therefore would be useful in rocket propulsion systems.

Genome-wide Linkage and Positional Association Study of Blood Pressure Response to Dietary Sodium Intervention

PubMed Central

Mei, Hao; Gu, Dongfeng; Hixson, James E.; Rice, Treva K.; Chen, Jing; Shimmin, Lawrence C.; Schwander, Karen; Kelly, Tanika N.; Liu, De-Pei; Chen, Shufeng; Huang, Jian-feng; Jaquish, Cashell E.; Rao, Dabeeru C.; He, Jiang

2012-01-01

The authors conducted a genome-wide linkage scan and positional association analysis to identify the genetic determinants of salt sensitivity of blood pressure (BP) in a large family-based, dietary-feeding study. The dietary intervention was conducted among 1,906 participants in rural China (2003–2005). A 7-day low-sodium intervention was followed by a 7-day high-sodium intervention. Salt sensitivity was defined as BP responses to low- and high-sodium interventions. Signals of the logarithm of the odds to the base 10 (LOD ≥ 3) were detected at 33–42 centimorgans of chromosome 2 (2p24.3-2p24.1), with a maximum LOD score of 3.33 for diastolic blood pressure responses to high-sodium intervention. LOD scores were 2.35–2.91 for mean arterial pressure (MAP) and 0.80–1.49 for systolic blood pressure responses in this region, respectively. Correcting for multiple tests, single nucleotide polymorphism (SNP) rs11674786 (2.7 kilobases upstream of the family with sequence similarity 84, member A, gene (FAM84A)) in the linkage region was significantly associated with diastolic blood pressure (P = 0.0007) and MAP responses (P = 0.0007), and SNP rs16983422 (2.8 kilobases upstream of the visinin-like 1 gene (VSNL1)) was marginally associated with diastolic blood pressure (P = 0.005) and MAP responses (P = 0.005). An additive interaction between SNPs rs11674786 and rs16983422 was observed, with P = 7.00 × 10−5 and P = 7.23 × 10−5 for diastolic blood pressure and MAP responses, respectively. The authors concluded that genetic region 2p24.3-2p24.1 might harbor functional variants for the salt sensitivity of BP. PMID:22865701

Arterial pressure suffices to increase liver stiffness.

PubMed

Piecha, Felix; Peccerella, Teresa; Bruckner, Tom; Seitz, Helmut-Karl; Rausch, Vanessa; Mueller, Sebastian

2016-11-01

Noninvasive measurement of liver stiffness (LS) has been established to screen for liver fibrosis. Since LS is also elevated in response to pressure-related conditions such as liver congestion, this study was undertaken to learn more about the role of arterial pressure on LS. LS was measured by transient elastography (μFibroscan platform, Echosens, Paris, France) during single intravenous injections of catecholamines in anesthetized rats with and without thioacetamide (TAA)-induced fibrosis. The effect of vasodilating glycerol trinitrate (GTN) on LS was also studied. Pressures in the abdominal aorta and caval and portal veins were measured in real time with the PowerLab device (AD Instruments, Dunedin, New Zealand). Baseline LS values in all rats (3.8 ± 0.5 kPa, n = 25) did not significantly differ from those in humans. Epinephrine and norepinephrine drastically increased mean arterial pressure (MAP) from 82 to 173 and 156 mmHg. Concomitantly, LS almost doubled from 4 to 8 kPa, while central venous pressure remained unchanged. Likewise, portal pressure only showed a slight and delayed increase. In the TAA-induced fibrosis model, LS increased from 9.5 ± 1.0 to 25.6 ± 14.7 kPa upon epinephrine injection and could efficiently be decreased by GTN. We finally show a direct association in humans in a physiological setting of elevated cardiac output and MAP. During continuous spinning at 200 W, MAP increased from 84 ± 8 to 99 ± 11 mmHg while LS significantly increased from 4.4 ± 1.8 to 6.7 ± 2.1 kPa. In conclusion, our data show that arterial pressure suffices to increase LS. Moreover, lowering MAP efficiently decreases LS in fibrotic livers that are predominantly supplied by arterial blood. Copyright © 2016 the American Physiological Society.

Radial to femoral arterial blood pressure differences in septic shock patients receiving high-dose norepinephrine therapy.

PubMed

Kim, Won Young; Jun, Jong Hun; Huh, Jin Won; Hong, Sang Bum; Lim, Chae-Man; Koh, Younsuck

2013-12-01

The accuracy of arterial blood pressure (ABP) monitoring is crucial in treating septic shock patients. Clinically significant differences in central to peripheral ABP could develop into sepsis during vasopressor therapy. The aim of this study was to investigate the difference between radial (peripheral) and femoral (central) ABP in septic shock patients receiving high-dose norepinephrine (NE) therapy. This prospective observational study comparing simultaneous intra-arterial measurements of radial and femoral ABP was performed at a university-affiliated, tertiary referral center between October 2008 and March 2009. Patients with septic shock who needed continuous blood pressure monitoring and high-dose NE therapy 0.1 µg/kg per minute or greater to maintain mean arterial pressure (MAP) of 65 mmHg or greater were included. Statistical analysis was conducted using the Bland-Altman method for comparison of repeated measures. In total, 250 sets of systolic, mean, and diastolic femoral and radial ABP were recorded at baseline and after NE titration. Arterial blood pressure readings from the radial artery were underestimated compared with those from the femoral artery. Overall bias (mean difference between simultaneous measurements) between radial and femoral MAP was +4.9 mmHg; however, during high-dose NE therapy, the bias increased to +6.2 mmHg (95% limits of agreement: -6.0 to +18.3 mmHg). Clinically significant radial-femoral MAP differences (MAP ≥5 mmHg) occurred in up to 62.2% of patients with high-dose NE therapy. Radial artery pressure frequently underestimates central pressure in septic shock patients receiving high-dose NE therapy. Femoral arterial pressure monitoring may be more appropriate when high-dose NE therapy is administered.

Atmospheric pressure and temperature profiling using near IR differential absorption lidar

NASA Technical Reports Server (NTRS)

Korb, C. L.; Schwemmer, G. K.; Dombrowski, M.; Weng, C. Y.

1983-01-01

The present investigation is concerned with differential absorption lidar techniques for remotely measuring the atmospheric temperature and pressure profile, surface pressure, and cloud top pressure-height. The procedure used in determining the pressure is based on the conduction of high-resolution measurements of absorption in the wings of lines in the oxygen A band. Absorption with respect to these areas is highly pressure sensitive in connection with the mechanism of collisional line broadening. The method of temperature measurement utilizes a determination of the absorption at the center of a selected line in the oxygen A band which originates from a quantum state with high ground state energy.

Normal and Differential SAR Interferometry

DTIC Science & Technology

2005-02-01

incorporating the use of a rough DEM. [ Adragna 1995]. The same technique is also used for flat Earth removal, and for differential interferometry (Cap.5...and F. Adragna , 1994. Radar Interferometric Mapping of Deformation in the Year After the Landers Earthquake, Nature, Vol. 369, pp. 227-230 Massonnet...D., M. Rossi, C. Carmona, F. Adragna , G. Peltzer, K. Feigi, and T. Rabaute, 1993. The Displacement Field of the Landers Earthquake Mapped by Radar

Sea Ice Detection Based on Differential Delay-Doppler Maps from UK TechDemoSat-1

PubMed Central

Zhu, Yongchao; Yu, Kegen; Zou, Jingui; Wickert, Jens

2017-01-01

Global Navigation Satellite System (GNSS) signals can be exploited to remotely sense atmosphere and land and ocean surface to retrieve a range of geophysical parameters. This paper proposes two new methods, termed as power-summation of differential Delay-Doppler Maps (PS-D) and pixel-number of differential Delay-Doppler Maps (PN-D), to distinguish between sea ice and sea water using differential Delay-Doppler Maps (dDDMs). PS-D and PN-D make use of power-summation and pixel-number of dDDMs, respectively, to measure the degree of difference between two DDMs so as to determine the transition state (water-water, water-ice, ice-ice and ice-water) and hence ice and water are detected. Moreover, an adaptive incoherent averaging of DDMs is employed to improve the computational efficiency. A large number of DDMs recorded by UK TechDemoSat-1 (TDS-1) over the Arctic region are used to test the proposed sea ice detection methods. Through evaluating against ground-truth measurements from the Ocean Sea Ice SAF, the proposed PS-D and PN-D methods achieve a probability of detection of 99.72% and 99.69% respectively, while the probability of false detection is 0.28% and 0.31% respectively. PMID:28704948

Analysis of the Pressure Distribution Qualities of a Silicone Border Foam Dressing.

PubMed

Miller, Stephannie K; Sharma, Neal; Aberegg, Lauren C; Blasiole, Kimberly N; Fulton, Judith A

2015-01-01

To determine whether application of a silicone foam dressing is associated with decreased interface pressures when applied to the heel. Prospective, within-subjects design. The study was conducted in a community-based hospital using a convenience sample of 50 healthy volunteers with a mean age of 39.6 years and mean body mass index of 26.6; 70% were female. Application of the silicone border foam dressing was randomized between the left and right heels. Participants were asked to lie down in the supine position on a viscoelastic foam mattress. Interface pressure measurements were captured using a pressure mapping system; measurements were taken once with the dressing applied to the heel (intervention map) and once without (control map). Data were captured after a 4-minute time period allowing stabilization. Analysis was based on mean interface pressure; data points were collected for both heels in each of the 2 frames, yielding 4 observations per subject. Application of the dressing was associated with a significant decrease in average pressure measurements as compared to the heel with no dressing applied (P < .001). Application of the dressing did not impact pressure readings for the heel to which no dressing was applied (P = .53), and application of the dressing to either the left or right heel did not impact pressure readings (ie, the random effect was insignificant; P = .9). Application of a silicone border foam dressing is associated with significant reduction in interface pressure and may be considered as part of a pressure ulcer prevention program.

Piston rod seal for a Stirling engine

DOEpatents

Shapiro, Wilbur

1984-01-01

In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

Sex-specific associations between cerebrovascular blood pressure autoregulation and cardiopulmonary injury in neonatal encephalopathy and therapeutic hypothermia.

PubMed

Chavez-Valdez, Raul; O'Connor, Matthew; Perin, Jamie; Reyes, Michael; Armstrong, Jillian; Parkinson, Charlamaine; Gilmore, Maureen; Jennings, Jacky; Northington, Frances J; Lee, Jennifer K

2017-05-01

Cardiopulmonary injury is common in neonatal encephalopathy, but the link with cerebrovascular dysfunction is unknown. We hypothesized that alterations of cerebral autoregulation are associated with cardiopulmonary injury in neonates treated with therapeutic hypothermia (TH) for neonatal encephalopathy. The cerebral hemoglobin volume index (HVx) from near-infrared spectroscopy was used to identify the mean arterial blood pressure (MAP) with optimal autoregulatory vasoreactivity (MAP OPT ). We measured associations between MAP relative to MAP OPT and indicators of cardiopulmonary injury (duration of mechanical respiratory support and administration of inhaled nitric oxide (iNO), milrinone, or steroids). We identified associations between cerebrovascular autoregulation and cardiopulmonary injury that were often sex-specific. Greater MAP deviation above MAP OPT was associated with shorter duration of intubation in boys but longer ventilatory support in girls. Greater MAP deviation below MAP OPT related to longer intensive care stay in boys. Milrinone was associated with greater MAP deviation below MAP OPT in girls. MAP deviation from MAP OPT may relate to cardiopulmonary injury after neonatal encephalopathy, and sex may modulate this relationship. Whereas MAP above MAP OPT may protect the brain and lungs in boys, it may be related to cardiopulmonary injury in girls. Future studies are needed to characterize the role of sex in these associations.

Problem of Auroral Oval Mapping and Multiscale Auroral Structures

NASA Astrophysics Data System (ADS)

Antonova, Elizaveta; Stepanova, Marina; Kirpichev, Igor; Vovchenko, Vadim; Vorobjev, Viachislav; Yagodkina, Oksana

The problem of the auroral oval mapping to the equatorial plane is reanalyzed taking into account the latest results of the analysis of plasma pressure distribution at low altitudes and at the equatorial plane. Statistical pictures of pressure distribution at low latitudes are obtained using data of DMSP observations. We obtain the statistical pictures of pressure distribution at the equatorial plane using data of THEMIS mission. Results of THEMIS observations demonstrate the existence of plasma ring surrounding the Earth at geocentric distances from ~6 till ~12Re. Plasma pressure in the ring is near to isotropic and its averaged values are larger than 0.2 nPa. We take into account that isotropic plasma pressure is constant along the field line and that the existence of field-aligned potential drops in the region of the acceleration of auroral electrons leads to pressure decrease at low altitudes. We show that most part of quite time auroral oval does not map to the real plasma sheet. It maps to the surrounding the Earth plasma ring. We also show that transverse currents in the plasma ring are closed inside the magnetosphere forming the high latitude continuation of the ordinary ring current. The obtained results are used for the explanation of ring like form of the auroral oval. We also analyze the processes of the formation of multiscale auroral structures including thin auroral arcs and discuss the difficulties of the theories of alfvenic acceleration of auroral electrons.

Low Differential Pressure Generator

NASA Technical Reports Server (NTRS)

Stout, Stephen J. (Inventor); Deyoe, Richard T. (Inventor)

1997-01-01

A method and apparatus for evaluating low differential pressure transducers includes a pressure generator in the form of a piston-cylinder assembly having a piston that may be manually positioned precisely within the cylinder to change the volume and thus the pressure at respective sides of the piston. At one side of the piston the cylinder communicates with a first chamber and at the other side of the piston the cylinder communicates with a second chamber, the first and second chambers being formed within a common tank by a partition wall. The chambers each communicate with the transducer to be evaluated and a standard pre-calibrated transducer the transducers being connected fluidly in parallel so that a pressure differential between air in the two chambers resulting from movement of the piston within the cylinder is communicated to both the transducer to be evaluated and the standard transducer, and the outputs of the transducers is observed and recorded.

A Lateral Differential Resonant Pressure Microsensor Based on SOI-Glass Wafer-Level Vacuum Packaging.

PubMed

Xie, Bo; Xing, Yonghao; Wang, Yanshuang; Chen, Jian; Chen, Deyong; Wang, Junbo

2015-09-21

This paper presents the fabrication and characterization of a resonant pressure microsensor based on SOI-glass wafer-level vacuum packaging. The SOI-based pressure microsensor consists of a pressure-sensitive diaphragm at the handle layer and two lateral resonators (electrostatic excitation and capacitive detection) on the device layer as a differential setup. The resonators were vacuum packaged with a glass cap using anodic bonding and the wire interconnection was realized using a mask-free electrochemical etching approach by selectively patterning an Au film on highly topographic surfaces. The fabricated resonant pressure microsensor with dual resonators was characterized in a systematic manner, producing a quality factor higher than 10,000 (~6 months), a sensitivity of about 166 Hz/kPa and a reduced nonlinear error of 0.033% F.S. Based on the differential output, the sensitivity was increased to two times and the temperature-caused frequency drift was decreased to 25%.

A Lateral Differential Resonant Pressure Microsensor Based on SOI-Glass Wafer-Level Vacuum Packaging

PubMed Central

Xie, Bo; Xing, Yonghao; Wang, Yanshuang; Chen, Jian; Chen, Deyong; Wang, Junbo

2015-01-01

This paper presents the fabrication and characterization of a resonant pressure microsensor based on SOI-glass wafer-level vacuum packaging. The SOI-based pressure microsensor consists of a pressure-sensitive diaphragm at the handle layer and two lateral resonators (electrostatic excitation and capacitive detection) on the device layer as a differential setup. The resonators were vacuum packaged with a glass cap using anodic bonding and the wire interconnection was realized using a mask-free electrochemical etching approach by selectively patterning an Au film on highly topographic surfaces. The fabricated resonant pressure microsensor with dual resonators was characterized in a systematic manner, producing a quality factor higher than 10,000 (~6 months), a sensitivity of about 166 Hz/kPa and a reduced nonlinear error of 0.033% F.S. Based on the differential output, the sensitivity was increased to two times and the temperature-caused frequency drift was decreased to 25%. PMID:26402679

The Distinct Effects of Estrogen and Hydrostatic Pressure on Mesenchymal Stem Cells Differentiation: Involvement of Estrogen Receptor Signaling.

PubMed

Zhao, Ying; Yi, Fei-Zhou; Zhao, Yin-Hua; Chen, Yong-Jin; Ma, Heng; Zhang, Min

2016-10-01

This study aimed to investigate the differential and synergistic effects of mechanical stimulation and estrogen on the proliferation and osteogenic or chondrogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs) and the roles of estrogen receptor (ER) in them. BMSCs were isolated and cultured using the whole bone marrow adherence method, and flow cytometry was used to identify the surface marker molecules of BMSCs. Cells were pre-treated with 1 nM 17β-estradiol or 1 nM of the estrogen receptor antagonist tamoxifen. Then, the cells were stimulated with hydrostatic pressure. Assessment included flow cytometry analysis of the cell cycle; immunofluorescent staining for F-actin; protein quantification for MAPK protein; and mRNA analysis for Col I, OCN, OPN and BSP after osteogenic induction and Sox-9, Aggrecan and Col-II after chondrogenic induction. Hydrostatic pressure (90 kPa/1 h) and 1 nM 17β-estradiol enhanced the cellular proliferation ability and the cytoskeleton activity but without synergistic biological effects. Estrogen activated ERKs and JNKs simultaneously and promoted the osteogenic differentiation, whereas the pressure just caused JNK-1/2 activation and promoted the chondrogenic differentiation of BMSCs. Estrogen had antagonism effect on chondrogenic promotion of hydrostatic pressure. Mechanobiological effects of hydrostatic pressure are closely associated with ERα activity. MAPK molecules and F-actin were likely to be important mediator molecules in the ER-mediated mechanotransduction of BMSCs.

Reversible effects of oxygen partial pressure on genes associated with placental angiogenesis and differentiation in primary-term cytotrophoblast cell culture.

PubMed

Debiève, F; Depoix, C; Gruson, D; Hubinont, C

2013-09-01

Timely regulated changes in oxygen partial pressure are important for placental formation. Disturbances could be responsible for pregnancy-related diseases like preeclampsia and intrauterine growth restriction. We aimed to (i) determine the effect of oxygen partial pressure on cytotrophoblast differentiation; (ii) measure mRNA expression and protein secretion from genes associated with placental angiogenesis; and (iii) determine the reversibility of these effects at different oxygen partial pressures. Term cytotrophoblasts were incubated at 21% and 2.5% O2 for 96 hr, or were switched between the two oxygen concentrations after 48 hr. Real-time PCR and enzyme-linked immunosorbent assays (ELISAs) were used to evaluate cell fusion and differentiation, measuring transcript levels for those genes involved in cell fusion and placental angiogenesis, including VEGF, PlGF, VEGFR1, sVEGFR1, sENG, INHA, and GCM1. Cytotrophoblasts underwent fusion and differentiation in 2.5% O2 . PlGF expression was inhibited while sVEGFR1 expression increased. VEGF and sENG mRNA expressions increased in 2.5% compared to 21% O2 , but no protein was detected in the cell supernatants. Finally, GCM1 mRNA expression increased during trophoblast differentiation at 21% O2 , but was inhibited at 2.5% O2 . These mRNA expression effects were reversed by returning the cells to 21% O2 . Thus, low-oxygen partial pressure does not inhibit term-cytotrophoblast cell fusion and differentiation in vitro. Lowering the oxygen partial pressure from 21% to 2.5% caused normal-term trophoblasts to reversibly modify their expression of genes associated with placental angiogenesis. This suggests that modifications observed in pregnancy diseases such as preeclampsia or growth retardation are probably due to an extrinsic effect on trophoblasts. Copyright © 2013 Wiley Periodicals, Inc.

Pressure mapping at orthopaedic joint interfaces with fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Mohanty, Lipi; Tjin, Swee Chuan

2006-02-01

We present the concept of a fiber-optic sensor that can be used for pressure mapping at the prosthetic knee joint, in vitro and in vivo. An embedded array of fiber Bragg gratings is used to measure the load on the tibial spacer. The sensor gives the magnitude and the location of the applied load. The effect of material properties on the sensitivity of each subgrating is presented. The wavelength-shift maps show the malalignment of implants and demonstrate the potential of this sensor for use during total knee arthroplasty.

Self-Powered High-Resolution and Pressure-Sensitive Triboelectric Sensor Matrix for Real-Time Tactile Mapping.

PubMed

Wang, Xiandi; Zhang, Hanlu; Dong, Lin; Han, Xun; Du, Weiming; Zhai, Junyi; Pan, Caofeng; Wang, Zhong Lin

2016-04-20

A triboelectric sensor matrix (TESM) can accurately track and map 2D tactile sensing. A self-powered, high-resolution, pressure-sensitive, flexible and durable TESM with 16 × 16 pixels is fabricated for the fast detection of single-point and multi-point touching. Using cross-locating technology, a cross-type TESM with 32 × 20 pixels is developed for more rapid tactile mapping, which significantly reduces the addressing lines from m × n to m + n. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Noninvasive Hemodynamic Measurements During Neurosurgical Procedures in Sitting Position.

PubMed

Schramm, Patrick; Tzanova, Irene; Gööck, Tilman; Hagen, Frank; Schmidtmann, Irene; Engelhard, Kristin; Pestel, Gunther

2017-07-01

Neurosurgical procedures in sitting position need advanced cardiovascular monitoring. Transesophageal echocardiography (TEE) to measure cardiac output (CO)/cardiac index (CI) and stroke volume (SV), and invasive arterial blood pressure measurements for systolic (ABPsys), diastolic (ABPdiast) and mean arterial pressure (MAP) are established monitoring technologies for these kind of procedures. A noninvasive device for continuous monitoring of blood pressure and CO based on a modified Penaz technique (volume-clamp method) was introduced recently. In the present study the noninvasive blood pressure measurements were compared with invasive arterial blood pressure monitoring, and the noninvasive CO monitoring to TEE measurements. Measurements of blood pressure and CO were performed in 35 patients before/after giving a fluid bolus and a change from supine to sitting position, start of surgery, and repositioning from sitting to supine at the end of surgery. Data pairs from the noninvasive device (Nexfin HD) versus arterial line measurements (ABPsys, ABPdiast, MAP) and versus TEE (CO, CI, SV) were compared using Bland-Altman analysis and percentage error. All parameters compared (CO, CI, SV, ABPsys, ABPdiast, MAP) showed a large bias and wide limits of agreement. Percentage error was above 30% for all parameters except ABPsys. The noninvasive device based on a modified Penaz technique cannot replace arterial blood pressure monitoring or TEE in anesthetized patients undergoing neurosurgery in sitting position.

Regulation of Cell Cycle and Stress Responses to Hydrostatic Pressure in Fission Yeast

PubMed Central

George, Vinoj T.; Brooks, Gavin

2007-01-01

We have investigated the cellular responses to hydrostatic pressure by using the fission yeast Schizosaccharomyces pombe as a model system. Exposure to sublethal levels of hydrostatic pressure resulted in G2 cell cycle delay. This delay resulted from Cdc2 tyrosine-15 (Y-15) phosphorylation, and it was abrogated by simultaneous disruption of the Cdc2 kinase regulators Cdc25 and Wee1. However, cell cycle delay was independent of the DNA damage, cytokinesis, and cell size checkpoints, suggesting a novel mechanism of Cdc2-Y15 phosphorylation in response to hydrostatic pressure. Spc1/Sty1 mitogen-activated protein (MAP) kinase, a conserved member of the eukaryotic stress-activated p38, mitogen-activated protein (MAP) kinase family, was rapidly activated after pressure stress, and it was required for cell cycle recovery under these conditions, in part through promoting polo kinase (Plo1) phosphorylation on serine 402. Moreover, the Spc1 MAP kinase pathway played a key role in maintaining cell viability under hydrostatic pressure stress through the bZip transcription factor, Atf1. Further analysis revealed that prestressing cells with heat increased barotolerance, suggesting adaptational cross-talk between these stress responses. These findings provide new insight into eukaryotic homeostasis after exposure to pressure stress. PMID:17699598

Closed Loop Software Control of the MIDEX Power System

NASA Technical Reports Server (NTRS)

Castell, Karen; Hernandez-Pellerano, Amri; Wismer, Margaret

1998-01-01

The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. The design and analysis of the MAP attitude control system (ACS) have been refined since work previously reported. The full spacecraft and instrument flexible model was developed in NASTRAN, and the resulting flexible modes were plotted and reduced with the Modal Significance Analysis Package (MSAP). The reduced-order model was used to perform the linear stability analysis for each control mode, the results of which are presented in this paper. Although MAP is going to a relatively disturbance-free Lissajous orbit around the Earth-Sun L2 Lagrange point, a detailed disturbance-torque analysis is required because there are only a small number of opportunities for momentum unloading each year. Environmental torques, including solar pressure at L2, and aerodynamic and gravity gradient during phasing-loop orbits, were calculated and simulated. A simple model of fuel slosh was derived to model its effect on the motion of the spacecraft. In addition, a thruster mode linear impulse controller was developed to meet the accuracy requirements of the phasing loop burns. A dynamic attitude error limiter was added to improve the performance of the ACS during large attitude slews. The result of this analysis is a stable ACS subsystem that meets all of the mission's requirements.

A U-shaped Association Between Blood Pressure and Cognitive Impairment in Chinese Elderly.

PubMed

Lv, Yue-Bin; Zhu, Peng-Fei; Yin, Zhao-Xue; Kraus, Virginia Byers; Threapleton, Diane; Chei, Choy-Lye; Brasher, Melanie Sereny; Zhang, Juan; Qian, Han-Zhu; Mao, Chen; Matchar, David Bruce; Luo, Jie-Si; Zeng, Yi; Shi, Xiao-Ming

2017-02-01

Higher or lower blood pressure may relate to cognitive impairment, whereas the relationship between blood pressure and cognitive impairment among the elderly is not well-studied. The study objective was to determine whether blood pressure is associated with cognitive impairment in the elderly, and, if so, to accurately describe the association. Cross-sectional data from the sixth wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) conducted in 2011. Community-based setting in longevity areas in China. A total of 7144 Chinese elderly aged 65 years and older were included in the sample. Systolic blood pressures (SBP) and diastolic blood pressures (DBP) were measured, pulse pressure (PP) was calculated as (SBP) - (DBP) and mean arterial pressures (MAP) was calculated as 1/3(SBP) + 2/3(DBP). Cognitive function was assessed via a validated Mini-Mental State Examination (MMSE). Based on the results of generalized additive models (GAMs), U-shaped associations were identified between cognitive impairment and SBP, DBP, PP, and MAP. The cutpoints at which risk for cognitive impairment (MMSE <24) was minimized were determined by quadratic models as 141 mm Hg, 85 mm Hg, 62 mm Hg, and 103 mm Hg, respectively. In the logistic models, U-shaped associations remained for SBP, DBP, and MAP but not PP. Below the identified cutpoints, each 1-mm Hg decrease in blood pressure corresponded to 0.7%, 1.1%, and 1.1% greater risk in the risk of cognitive impairment, respectively. Above the cutpoints, each 1-mm Hg increase in blood pressure corresponded to 1.2%, 1.8%, and 2.1% greater risk of cognitive impairment for SBP, DBP, and MAP, respectively. A U-shaped association between blood pressure and cognitive function in an elderly Chinese population was found. Recognition of these instances is important in identifying the high-risk population for cognitive impairment and to individualize blood pressure management for cognitive impairment prevention. Copyright © 2016 AMDA – The Society for Post-Acute and Long-Term Care Medicine. All rights reserved.

Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis.

PubMed

Huang, Mu; Allen, Dustin R; Keller, David M; Fadel, Paul J; Frohman, Elliot M; Davis, Scott L

2016-07-01

Multiple sclerosis (MS), a progressive neurological disease, can lead to impairments in the autonomic control of cardiovascular function. We tested the hypothesis that individuals with relapsing-remitting MS (n = 10; 7 females, 3 males; 13 ± 4 yr from diagnosis) exhibit impaired carotid baroreflex control of blood pressure and heart rate compared with sex, age, and body weight-matched healthy individuals (CON: n = 10; 7 females, 3 males). At rest, 5-s trials of neck pressure (NP; +40 Torr) and neck suction (NS; -60 Torr) were applied to simulate carotid hypotension and hypertension, respectively, while mean arterial pressure (MAP; finger photoplethysmography), heart rate (HR), cardiac output (CO; Modelflow), and total vascular conductance (TVC) were continuously measured. In response to NP, there was a blunted increase in peak MAP responses (MS: 5 ± 2 mmHg) in individuals with MS compared with healthy controls (CON: 9 ± 3 mmHg; P = 0.005), whereas peak HR responses were not different between groups. At the peak MAP response to NP, individuals with MS demonstrated an attenuated decrease in TVC (MS, -10 ± 4% baseline vs. CON, -15 ± 4% baseline, P = 0.012), whereas changes in CO were similar between groups. Following NS, all cardiovascular responses (i.e., nadir MAP and HR and percent changes in CO and TVC) were not different between MS and CON groups. These data suggest that individuals with MS have impaired carotid baroreflex control of blood pressure via a blunted vascular conductance response resulting in a diminished ability to increase MAP in response to a hypotensive challenge. Copyright © 2016 the American Physiological Society.

Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis

PubMed Central

Huang, Mu; Allen, Dustin R.; Keller, David M.; Fadel, Paul J.; Frohman, Elliot M.

2016-01-01

Multiple sclerosis (MS), a progressive neurological disease, can lead to impairments in the autonomic control of cardiovascular function. We tested the hypothesis that individuals with relapsing-remitting MS (n = 10; 7 females, 3 males; 13 ± 4 yr from diagnosis) exhibit impaired carotid baroreflex control of blood pressure and heart rate compared with sex, age, and body weight-matched healthy individuals (CON: n = 10; 7 females, 3 males). At rest, 5-s trials of neck pressure (NP; +40 Torr) and neck suction (NS; −60 Torr) were applied to simulate carotid hypotension and hypertension, respectively, while mean arterial pressure (MAP; finger photoplethysmography), heart rate (HR), cardiac output (CO; Modelflow), and total vascular conductance (TVC) were continuously measured. In response to NP, there was a blunted increase in peak MAP responses (MS: 5 ± 2 mmHg) in individuals with MS compared with healthy controls (CON: 9 ± 3 mmHg; P = 0.005), whereas peak HR responses were not different between groups. At the peak MAP response to NP, individuals with MS demonstrated an attenuated decrease in TVC (MS, −10 ± 4% baseline vs. CON, −15 ± 4% baseline, P = 0.012), whereas changes in CO were similar between groups. Following NS, all cardiovascular responses (i.e., nadir MAP and HR and percent changes in CO and TVC) were not different between MS and CON groups. These data suggest that individuals with MS have impaired carotid baroreflex control of blood pressure via a blunted vascular conductance response resulting in a diminished ability to increase MAP in response to a hypotensive challenge. PMID:27075533

Intraspecific scaling of arterial blood pressure in the Burmese python.

PubMed

Enok, Sanne; Slay, Christopher; Abe, Augusto S; Hicks, James W; Wang, Tobias

2014-07-01

Interspecific allometric analyses indicate that mean arterial blood pressure (MAP) increases with body mass of snakes and mammals. In snakes, MAP increases in proportion to the increased distance between the heart and the head, when the heart-head vertical distance is expressed as ρgh (where ρ is the density of blood, G: is acceleration due to gravity and h is the vertical distance above the heart), and the rise in MAP is associated with a larger heart to normalize wall stress in the ventricular wall. Based on measurements of MAP in Burmese pythons ranging from 0.9 to 3.7 m in length (0.20-27 kg), we demonstrate that although MAP increases with body mass, the rise in MAP is merely half of that predicted by heart-head distance. Scaling relationships within individual species, therefore, may not be accurately predicted by existing interspecific analyses. © 2014. Published by The Company of Biologists Ltd.

Mapping simulated scenes with skeletal remains using differential GPS in open environments: an assessment of accuracy and practicality.

PubMed

Walter, Brittany S; Schultz, John J

2013-05-10

Scene mapping is an integral aspect of processing a scene with scattered human remains. By utilizing the appropriate mapping technique, investigators can accurately document the location of human remains and maintain a precise geospatial record of evidence. One option that has not received much attention for mapping forensic evidence is the differential global positioning (DGPS) unit, as this technology now provides decreased positional error suitable for mapping scenes. Because of the lack of knowledge concerning this utility in mapping a scene, controlled research is necessary to determine the practicality of using newer and enhanced DGPS units in mapping scattered human remains. The purpose of this research was to quantify the accuracy of a DGPS unit for mapping skeletal dispersals and to determine the applicability of this utility in mapping a scene with dispersed remains. First, the accuracy of the DGPS unit in open environments was determined using known survey markers in open areas. Secondly, three simulated scenes exhibiting different types of dispersals were constructed and mapped in an open environment using the DGPS. Variables considered during data collection included the extent of the dispersal, data collection time, data collected on different days, and different postprocessing techniques. Data were differentially postprocessed and compared in a geographic information system (GIS) to evaluate the most efficient recordation methods. Results of this study demonstrate that the DGPS is a viable option for mapping dispersed human remains in open areas. The accuracy of collected point data was 11.52 and 9.55 cm for 50- and 100-s collection times, respectfully, and the orientation and maximum length of long bones was maintained. Also, the use of error buffers for point data of bones in maps demonstrated the error of the DGPS unit, while showing that the context of the dispersed skeleton was accurately maintained. Furthermore, the application of a DGPS for accurate scene mapping is discussed and guidelines concerning the implementation of this technology for mapping human scattered skeletal remains in open environments are provided. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Surface pressure field mapping using luminescent coatings

NASA Technical Reports Server (NTRS)

Mclachlan, B. G.; Kavandi, J. L.; Callis, J. B.; Gouterman, M.; Green, E.; Khalil, G.; Burns, D.

1993-01-01

In recent experiments we demonstrated the feasibility of using the oxygen dependence of luminescent molecules for surface pressure measurement in aerodynamic testing. This technique is based on the observation that for many luminescent molecules the light emitted increases as the oxygen partial pressure, and thus the air pressure, the molecules see decreases. In practice the surface to be observed is coated with an oxygen permeable polymer containing a luminescent molecule and illuminated with ultraviolet radiation. The airflow induced surface pressure field is seen as a luminescence intensity distribution which can be measured using quantitative video techniques. Computer processing converts the video data into a map of the surface pressure field. The experiments consisted of evaluating a trial luminescent coating in measuring the static surface pressure field over a two-dimensional NACA-0012 section model airfoil for Mach numbers ranging from 0.3 and 0.66. Comparison of the luminescent coating derived pressures were made to those obtained from conventional pressure taps. The method along with the experiment and its results will be described.

RADON PRESSURE DIFFERENTIAL PROJECT - PHASE I - FLORIDA RESEARCH PROGRAM

EPA Science Inventory

The report gives results of tests on 70 central Florida houses to assess and characterize pressure differentials in new (age 5 years or less) Florida houses. Blower door tests determined house airtightness and air distribution system leakage. The 70 houses had an average airtight...

Temporally inter-comparable maps of terrestrial wilderness and the Last of the Wild

PubMed Central

Allan, James R.; Venter, Oscar; Watson, James E.M.

2017-01-01

Wilderness areas, defined as areas free of industrial scale activities and other human pressures which result in significant biophysical disturbance, are important for biodiversity conservation and sustaining the key ecological processes underpinning planetary life-support systems. Despite their importance, wilderness areas are being rapidly eroded in extent and fragmented. Here we present the most up-to-date temporally inter-comparable maps of global terrestrial wilderness areas, which are essential for monitoring changes in their extent, and for proactively planning conservation interventions to ensure their preservation. Using maps of human pressure on the natural environment for 1993 and 2009, we identified wilderness as all ‘pressure free’ lands with a contiguous area >10,000 km2. These places are likely operating in a natural state and represent the most intact habitats globally. We then created a regionally representative map of wilderness following the well-established ‘Last of the Wild’ methodology; which identifies the 10% area with the lowest human pressure within each of Earth’s 60 biogeographic realms, and identifies the ten largest contiguous areas, along with all contiguous areas >10,000 km2. PMID:29231923

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

Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

NASA Astrophysics Data System (ADS)

Rodi, A. R.; Leon, D. C.

2012-05-01

Geometric altitude data from a combined Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) system on the University of Wyoming King Air research aircraft are used to estimate acceleration effects on static pressure measurement. Using data collected during periods of accelerated flight, comparison of measured pressure with that derived from GNSS/IMU geometric altitude show that errors exceeding 150 Pa can occur which is significant in airspeed and atmospheric air motion determination. A method is developed to predict static pressure errors from analysis of differential pressure measurements from a Rosemount model 858 differential pressure air velocity probe. The method was evaluated with a carefully designed probe towed on connecting tubing behind the aircraft - a "trailing cone" - in steady flight, and shown to have a precision of about ±10 Pa over a wide range of conditions including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, compared to the GNSS/IMU data, this algorithm predicts corrections to a precision of better than ±20 Pa. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are examined.

The H2 + + He proton transfer reaction: quantum reactive differential cross sections to be linked with future velocity mapping experiments

NASA Astrophysics Data System (ADS)

Hernández Vera, Mario; Wester, Roland; Gianturco, Francesco Antonio

2018-01-01

We construct the velocity map images of the proton transfer reaction between helium and molecular hydrogen ion {{{H}}}2+. We perform simulations of imaging experiments at one representative total collision energy taking into account the inherent aberrations of the velocity mapping in order to explore the feasibility of direct comparisons between theory and future experiments planned in our laboratory. The asymptotic angular distributions of the fragments in a 3D velocity space is determined from the quantum state-to-state differential reactive cross sections and reaction probabilities which are computed by using the time-independent coupled channel hyperspherical coordinate method. The calculations employ an earlier ab initio potential energy surface computed at the FCI/cc-pVQZ level of theory. The present simulations indicate that the planned experiments would be selective enough to differentiate between product distributions resulting from different initial internal states of the reactants.

Quaternary Geologic Map of the Regina 4 Degrees x 6 Degrees Quadrangle, United States and Canada

USGS Publications Warehouse

Fullerton, David S.; Christiansen, Earl A.; Schreiner, Bryan T.; Colton, Roger B.; Clayton, Lee; Bush, Charles A.; Fullerton, David S.

2007-01-01

For scientific purposes, the map differentiates Quaternary surficial deposits and materials on the basis of clast lithology or composition, matrix texture or particle size, structure, genesis, stratigraphic relations, engineering geologic properties, and relative age, as shown on the correlation diagram and indicated in the 'Description of Map Units'. Deposits of some constructional landforms, such as end moraines, are distinguished as map units. Deposits of erosional landforms, such as outwash terraces, are not distinguished, although glaciofluvial, ice-contact, fluvial, and lacustrine deposits that are mapped may be terraced. Differentiation of sequences of fluvial and glaciofluvial deposits at this scale is not possible. For practical purposes, the map is a surficial materials map. Materials are distinguished on the basis of lithology or composition, texture or particle size, and other physical, chemical, and engineering characteristics. It is not a map of soils that are recognized and classified in pedology or agronomy. Rather, it is a generalized map of soils as recognized in engineering geology, or of substrata or parent materials in which pedologic or agronomic soils are formed. As a materials map, it serves as a base from which a variety of maps for use in planning engineering, land-use planning, or land-management projects can be derived and from which a variety of maps relating to earth surface processes and Quaternary geologic history can be derived.

Baroreflex dysfunction in sick newborns makes heart rate an unreliable surrogate for blood pressure changes.

PubMed

Govindan, Rathinaswamy B; Al-Shargabi, Tareq; Massaro, An N; Metzler, Marina; Andescavage, Nickie N; Joshi, Radhika; Dave, Rhiya; du Plessis, Adre

2016-06-01

Cerebral pressure passivity (CPP) in sick newborns can be detected by evaluating coupling between mean arterial pressure (MAP) and cerebral blood flow measured by near infra-red spectroscopy hemoglobin difference (HbD). However, continuous MAP monitoring requires invasive catheterization with its inherent risks. We tested whether heart rate (HR) could serve as a reliable surrogate for MAP in the detection of CPP in sick newborns. Continuous measurements of MAP, HR, and HbD were made and partitioned into 10-min epochs. Spectral coherence (COH) was computed between MAP and HbD (COHMAP-HbD) to detect CPP, between HR and HbD (COHHR-HbD) for comparison, and between MAP and HR (COHMAP-HR) to quantify baroreflex function (BRF). The agreement between COHMAP-HbD and COHHR-HbD was assessed using ROC analysis. We found poor agreement between COHMAP-HbD and COHHR-HbD in left hemisphere (area under the ROC curve (AUC) 0.68) and right hemisphere (AUC 0.71). Baroreflex failure (COHMAP-HR not significant) was present in 79% of epochs. Confining comparison to epochs with intact BRF showed an AUC of 0.85 for both hemispheres. In these sick newborns, HR was an unreliable surrogate for MAP required for the detection of CPP. This is likely due to the prevalence of BRF failure in these infants.

Global Ionospheric Perturbations Monitored by the Worldwide GPS Network

NASA Technical Reports Server (NTRS)

Ho, C. M.; Mannucci, A. T.; Lindqwister, U. J.; Pi, X. Q.

1996-01-01

Based on the delays of these (Global Positioning System-GPS)signals, we have generated high resolution global ionospheric TEC (Total Electronic Changes) maps at 15-minute intervals. Using a differential method comparing storm time maps with quiet time maps, we find that the ionopshere during this time storm has increased significantly (the percentage change relative to quiet times is greater than 150 percent) ...These preliminary results (those mentioned above plus other in the paper)indicate that the differential maping method, which is based on GPS network measurements appears to be a useful tool for studying the global pattern and evolution process of the entire ionospheric perturbation.

Differential Influence of Distinct Components of Increased Blood Pressure on Cardiovascular OutcomesR3

PubMed Central

Cheng, Susan; Gupta, Deepak K.; Claggett, Brian; Sharrett, A. Richey; Shah, Amil M.; Skali, Hicham; Takeuchi, Madoka; Ni, Hanyu; Solomon, Scott D.

2013-01-01

Elevation in blood pressure (BP) increases risk for all cardiovascular events. Nevertheless, the extent to which different indices of BP elevation may be associated to varying degrees with different cardiovascular outcomes remains unclear. We studied 13,340 participants (aged 54±6 years, 56% women, 27% black) of the Atherosclerosis Risk in Communities Study who were free of baseline cardiovascular disease. We used Cox proportional hazards models to compare the relative contributions of systolic (SBP), diastolic (DBP), pulse pressure (PP), and mean arterial pressure (MAP) to risk for coronary heart disease (CHD), heart failure (HF), stroke, and all-cause mortality. For each multivariable-adjusted model, the largest area under the receiver-operating curve (AUC) and smallest -2 log likelihood values were used to identify BP measures with the greatest contribution to risk prediction for each outcome. A total of 2095 CHD events, 1669 HF events, 771 stroke events, and 3016 deaths occurred during up to 18±5 years of follow up. In multivariable analyses adjusting for traditional cardiovascular risk factors, the BP measures with the greatest risk contributions were: SBP for CHD (AUC=0.74); PP for HF (AUC=0.79), SBP for stroke (AUC=0.74), and PP for all-cause mortality (AUC=0.74). With few exceptions, results were similar in analyses stratified by age, sex, and race. Our data indicate that distinct BP components contribute variably to risk for different cardiovascular outcomes. PMID:23876475

Influence of Partial O₂ Pressure on the Adhesion, Proliferation, and Osteogenic Differentiation of Human Dental Pulp Stem Cells on β-Tricalcium Phosphate Scaffold.

PubMed

Viña-Almunia, Jose; Mas-Bargues, Cristina; Borras, Consuelo; Gambini, Juan; El Alami, Marya; Sanz-Ros, Jorge; Peñarrocha, Miguel; Vina, Jose

To analyze, in vitro, the influence of O₂ pressure on the adhesion, proliferation, and osteogenic differentiation of human dental pulp stem cells (DPSC) on β-tricalcium phosphate (β-TCP) scaffold. DPSC, positive for the molecular markers CD133, Oct4, Nestin, Stro-1, and CD34, and negative for CD45, were isolated from extracted third molars. Experiments were started by seeding 200,000 cells on β-TCP cultured under 3% or 21% O₂ pressure. No osteogenic medium was used. Eight different cultures were performed at each time point under each O₂ pressure condition. Cell adhesion, proliferation, and differentiation over the biomaterial were evaluated at 7, 13, 18, and 23 days of culture. Cell adhesion was determined by light microscopy, proliferation by DNA quantification, and osteogenic differentiation by alkaline phosphatase (ALP) activity analysis. DPSC adhered to β-TCP with both O₂ conditions. Cell proliferation was found from day 7 of culture. Higher values were recorded at 3% O₂ in each time point. Statistically significant differences were recorded at 23 days of culture (P = .033). ALP activity was not detectable at 7 days. There was, however, an increase in ALP activity over time in both groups. At 13, 18, and 23 days of culture, higher ALP activity was recorded under 3% O₂ pressure. Statistical differences were found at day 23 (P = .014). DPSC display capacity of adhering to β-TCP under 3% or 21% O₂ pressure conditions. Cell proliferation on β-TCP phosphate is significantly higher at 3% than at 21% O₂ pressure, the most frequently used O₂ tension. β-TCP can itself promote osteogenic differentiation of DPSC and is enhanced under 3% O₂ compared with 21%.

Hypothalamic stimulation and baroceptor reflex interaction on renal nerve activity.

NASA Technical Reports Server (NTRS)

Wilson, M. F.; Ninomiya, I.; Franz, G. N.; Judy, W. V.

1971-01-01

The basal level of mean renal nerve activity (MRNA-0) measured in anesthetized cats was found to be modified by the additive interaction of hypothalamic and baroceptor reflex influences. Data were collected with the four major baroceptor nerves either intact or cut, and with mean aortic pressure (MAP) either clamped with a reservoir or raised with l-epinephrine. With intact baroceptor nerves, MRNA stayed essentially constant at level MRNA-0 for MAP below an initial pressure P1, and fell approximately linearly to zero as MAP was raised to P2. Cutting the baroceptor nerves kept MRNA at MRNA-0 (assumed to represent basal central neural output) independent of MAP. The addition of hypothalamic stimulation produced nearly constant increments in MRNA for all pressure levels up to P2, with complete inhibition at some level above P2. The increments in MRNA depended on frequency and location of the stimulus. A piecewise linear model describes MRNA as a linear combination of hypothalamic, basal central neural, and baroceptor reflex activity.

Roles for the sympathetic nervous system, renal nerves, and CNS melanocortin-4 receptor in the elevated blood pressure in hyperandrogenemic female rats.

PubMed

Maranon, Rodrigo; Lima, Roberta; Spradley, Frank T; do Carmo, Jussara M; Zhang, Howei; Smith, Andrew D; Bui, Elizabeth; Thomas, R Lucas; Moulana, Mohadetheh; Hall, John E; Granger, Joey P; Reckelhoff, Jane F

2015-04-15

Women with polycystic ovary syndrome (PCOS) have hyperandrogenemia and increased prevalence of risk factors for cardiovascular disease, including elevated blood pressure. We recently characterized a hyperandrogenemic female rat (HAF) model of PCOS [chronic dihydrotestosterone (DHT) beginning at 4 wk of age] that exhibits similar characteristics as women with PCOS. In the present studies we tested the hypotheses that the elevated blood pressure in HAF rats is mediated in part by sympathetic activation, renal nerves, and melanocortin-4 receptor (MC4R) activation. Adrenergic blockade with terazosin and propranolol or renal denervation reduced mean arterial pressure (MAP by telemetry) in HAF rats but not controls. Hypothalamic MC4R expression was higher in HAF rats than controls, and central nervous system MC4R antagonism with SHU-9119 (1 nmol/h icv) reduced MAP in HAF rats. Taking a genetic approach, MC4R null and wild-type (WT) female rats were treated with DHT or placebo from 5 to 16 wk of age. MC4R null rats were obese and had higher MAP than WT control rats, and while DHT increased MAP in WT controls, DHT failed to further increase MAP in MC4R null rats. These data suggest that increases in MAP with chronic hyperandrogenemia in female rats are due, in part, to activation of the sympathetic nervous system, renal nerves, and MC4R and may provide novel insights into the mechanisms responsible for hypertension in women with hyperandrogenemia such as PCOS. Copyright © 2015 the American Physiological Society.

Family history of diabetes modifies the effect of blood pressure for incident diabetes in Middle Eastern women: Tehran Lipid and Glucose Study.

PubMed

Hatami, M; Hadaegh, F; Khalili, D; Sheikholeslami, F; Azizi, F

2012-02-01

Elevated blood pressure (BP) may lead to incident diabetes. However, data about the effect of different BP components on incident diabetes in Middle Eastern women is lacking. We evaluated systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP) and mean arterial pressure (MAP) as independent predictors of diabetes in Iranian women. We performed a population-based prospective study among 3028 non-diabetic women, aged ≥20 years. Odds ratios (ORs) of diabetes were calculated for every 1 s.d. increase in SBP, DBP, PP and MAP. During ≈6 years of follow-up, 220 women developed diabetes. There were significant interactions between family history of diabetes and SBP, PP and MAP (P≤0.01) in predicting incident diabetes. In women without a family history of diabetes, all BP components were significantly associated with diabetes in the age-adjusted model; the risk factor-adjusted ORs were significant (P<0.05) for SBP, PP and MAP (1.30, 1.34 and 1.27, respectively) with similar predictive ability (area under the receiver operating characteristic curve ≈83%). In women with family history of diabetes, in the age-adjusted model, SBP, DBP and MAP were associated with diabetes; in multivariable model, they were not independent predictors of diabetes. In conclusion, in women without family history of diabetes, SBP, PP and MAP, were independent predictors of diabetes with almost similar predictive ability; hence, in the evaluation of the risk of BP components for prediction of diabetes, the presence of family history of diabetes should be considered.

Effects of arm elevation on radial artery pressure: a new method to distinguish hypovolemic shock and septic shock from hypotension.

PubMed

Xie, Zhiyi; Zhang, Zhenyu; Xu, Yuan; Zhou, Hua; Wu, Sheng; Wang, Zhong

2018-06-01

In this prospective observational study, we investigated the variability in radial artery invasive blood pressure associated with arm elevation in patients with different hemodynamic types. We carried out a prospective observational study using data from 73 general anesthesia hepatobiliary postoperative adult patients admitted to an ICU over a 1-year period. A standard procedure was used for the arm elevation test. The value of invasive radial arterial pressure was recorded at baseline, and 30 and 60 s after the arm had been raised from 0° to 90°. We compared the blood pressure before versus after arm elevation, and between hemodynamically stable, hypovolemic shock, and septic shock patient groups. In all 73 patients, systolic arterial pressure (SAP) decreased, diastolic arterial pressure (DAP) increased, and pulse pressure (PP) decreased at 30 and 60 s after arm elevation (P<0.01), but the mean arterial pressure (MAP) was unchanged (P>0.05). On comparing 30 and 60 s, there was no significant difference in SAP, DAP, PP, or MAP (P>0.05). In 40 hemodynamically stable patients, SAP and PP decreased, and DAP and MAP increased significantly at 30 and 60 s after arm elevation compared with baseline (P<0.01). In 16 hypovolemic patients, SAP, DAP, and MAP increased significantly compared with baseline at 30 and 60 s (P<0.01), but PP was unchanged (P>0.05). In 17 patients with septic shock, SAP, PP, and MAP decreased significantly versus baseline at 30 and 60 s (P<0.01), but DAP was unchanged (P>0.05). Comparison of the absolute value of pressure change of septic shock patients at 30 s after raising the arm showed that SAP, DAP, and MAP changes were significantly lower compared with those in hypovolemic shock and hemodynamically stable patients (P<0.01). The areas under the receiver operator characteristic curve for predicting septic shock was 0.930 [95% confidence interval (CI): 0.867-0.992, P< 0.001] for change value at 30 s after arm elevation of SAP. The best cut-off point for the SAP change value was -5 mmHg or less, with a sensitivity of 94.12%, a specificity of 80.36%, a positive likelihood ratio of 4.79 (95% CI: 2.8-8.2), and a negative likelihood ratio of 0.073 (95% CI: 0.01-0.5). Our study shows that hypovolemic shock and septic shock patients have significantly different radial artery invasive blood pressure changes in an arm elevation test, which could be applied as a new method to distinguish hypovolemic shock and septic shock from hypotension.

Modified Biot-Gassmann theory for calculating elastic velocities for unconsolidated and consolidated sediments

USGS Publications Warehouse

Lee, M.W.

2002-01-01

The classical Biot-Gassmann theory (BGT) generally overestimates shear-wave velocities of water-saturated sediments. To overcome this problem, a new theory is developed based on BGT and on the velocity ratio as a function of G(1 - ??)n, where ?? is porosity and n and G are constants. Based on laboratory data measured at ultrasonic frequencies, parameters for the new formulation are derived. This new theory is extended to include the effect of differential pressure and consolidation on the velocity ratio by making n a function of differential pressure and the rate of porosity reduction with respect to differential pressure. A scale G is introduced to compensate for discrepancies between measured and predicted velocities, mainly caused by the presence of clay in the matrix. As differential pressure increases and the rate of porosity reduction with respect to differential pressure decreases, the exponent n decreases and elastic velocities increase. Because velocity dispersion is not considered, this new formula is optimum for analyzing velocities measured at ultrasonic frequencies or for sediments having low dispersion characteristics such as clean sandstone with high permeability and lack of grain-scale local flow. The new formula is applied to predict velocities from porosity or from porosity and P-wave velocity and is in good agreement with laboratory and well log data. ?? 2004 Kluwer Academic Publishers. Printed in the Netherlands.

[Effect of external abdominal aorta compression on circulation during anesthesia induction in elderly patients].

PubMed

Li, Xiuman; Wang, Lixiang

2017-07-01

To investigate the effect of external abdominal aorta compression on circulation during anesthetic induction in elderly patients. A prospective randomized controlled trial was conducted. Patients with age of 60-75 years old, requiring a general anesthesia for non-abdominal surgery, and with II-III class of American Society of Anesthesiologists (ASA) physical status classification, and admitted to General Hospital of Chinese People's Armed Police Forces from January to April in 2017 were enrolled. They were divided into abdominal aorta pressure group and control group according to random number method, with 20 patients in each group. In both groups, anesthesia was induced with midazolam, propofol, fentanyl and cisatracurium, and was maintained with propofol, remifentanil and cisatracurium. After successful intubation, the anesthesia machine was changed into mechanical ventilation. The patients in abdominal aorta pressure group were given abdominal aorta pressure 1 minute after induction of general anesthesia with midazolam till 5 minutes after intubation. The mean arterial pressure (MAP), heart rate (HR) and blood oxygen saturation (SpO 2 ) were observed before anesthesia induction, immediately after anesthesia induction, immediately after intubation, 5 minutes and 10 minutes after intubation, respectively. The incidence of hypotension or bradycardia, and usage of ephedrine or atropine were recorded. There were no significant differences in MAP [mmHg (1 mmHg = 0.133 kPa): 83.6±4.7 vs. 82.9±4.7], HR (bpm: 67.3±5.9 vs. 65.9±5.7) and SpO 2 (0.962±0.007 vs. 0.960±0.009) before anesthesia induction between abdominal aorta pressure group and control group (all P > 0.05). Immediately after anesthesia induction, the MAP and HR in control group were significantly decreased as compared with those before anesthesia induction [MAP (mmHg): 70.0±8.7 vs. 82.9±4.7, HR (bpm): 60.7±6.7 vs. 65.9±5.7, both P < 0.05], and they were also significantly lower than those of abdominal aorta pressure group [MAP (mmHg): 83.1±3.9, HR (bpm): 66.8±4.9, both P < 0.05]. Immediately after intubation, the MAP and HR in control group were significantly increased as compared with those immediately after anesthesia induction [MAP (mmHg): 78.9±7.9 vs. 70.0±8.7, HR (bpm): 67.3±2.7 vs. 60.7±6.7, both P < 0.05], but the changes in MAP and HR in abdominal aorta pressure group were not obvious. During the anesthesia induction period, there was no statistical difference in SpO 2 change between the two groups. During induction of anesthesia, no adverse reaction was found in the abdominal aorta pressure group, but 4 patients with hypotension and 2 patients with bradycardia were found in the control group. Two patients with hypotension were treated with ephedrine, and 2 patients with bradycardia were treated with atropine. Anesthesia induction of elderly patients with abdominal aorta pressure can help maintain hemodynamic stability.

Poor Long-Term Blood Pressure Control after Intracerebral Hemorrhage

PubMed Central

Zahuranec, Darin B.; Wing, Jeffrey J.; Edwards, Dorothy F.; Menon, Ravi S.; Fernandez, Stephen J.; Burgess, Richard E.; Sobotka, Ian A.; German, Laura; Trouth, Anna J.; Shara, Nawar M.; Gibbons, M. Chris; Boden-Albala, Bernadette; Kidwell, Chelsea S.

2012-01-01

Background and Purpose Hypertension is the most important risk factor associated with intracerebral hemorrhage (ICH). We explored racial differences in blood pressure (BP) control after ICH and assessed predictors of BP control at presentation, 30 days, and 1 year in a prospective cohort study. Methods Subjects with spontaneous ICH were identified from the DiffErenCes in the Imaging of Primary Hemorrhage based on Ethnicity or Race (DECIPHER) Project. Blood pressure was compared by race at each time point. Multivariable linear regression was used to determine predictors of presenting mean arterial pressure (MAP), and longitudinal linear regression was used to assess predictors of MAP at follow-up. Results A total of 162 patients were included (mean age 59, 53% male, 77% black). MAP at presentation was 9.6 mmHg higher in blacks than whites despite adjustment for confounders (p=0.065). Fewer than 20% of patients had normal blood pressure (<120/80 mmHg) at 30 days or 1 year. While there was no difference at 30 days (p=0.331), blacks were more likely than whites to have Stage I/II hypertension at one year (p=0.036). Factors associated with lower MAP at follow-up in multivariable analysis were being married at baseline (p=0.032) and living in a facility (versus personal residence) at the time of BP measurement (p=0.023). Conclusions Long-term blood pressure control is inadequate in patients following ICH, particularly in blacks. Further studies are needed to understand the role of social support and barriers to control to identify optimal approaches to improve blood pressure in this high-risk population. PMID:22903494

First-trimester mean arterial blood pressure and the risk of preeclampsia: The Great Obstetrical Syndromes (GOS) study.

PubMed

Gasse, Cédric; Boutin, Amélie; Coté, Maxime; Chaillet, Nils; Bujold, Emmanuel; Demers, Suzanne

2018-04-01

To estimate the predictive value of first-trimester mean arterial pressure (MAP) for the hypertensive disorders of pregnancy (HDP). We performed a prospective cohort study of nulliparous women recruited at 11 0/7 -13 6/7  weeks. MAP was calculated from blood pressure measured on both arms simultaneously using an automated device taking a series of recordings until blood pressure stability was reached. MAP was reported as multiples of the median adjusted for gestational age. Participants were followed for development of gestational hypertension (GH), preeclampsia (PE), preterm PE (<37 weeks) and early-onset (EO) PE (<34 weeks). Receiver operating characteristic curves and the area under the curve (AUC) were used to estimate the predictive values of MAP. Multivariate logistic regressions were used to develop predictive models combining MAP and maternal characteristics. We obtained complete follow-up in 4700 (99%) out of 4749 eligible participants. GH without PE was observed in 250 (5.3%) participants, and PE in 241 (5.1%), including 33 (0.7%) preterm PE and 10 (0.2%) EO-PE. First-trimester MAP was associated with GH (AUC: 0.77; 95%CI: 0.74-0.80); term PE (0.73; 95%CI: 0.70-0.76), preterm PE (0.80; 95%CI: 0.73-0.87) and EO-PE (0.79; 95%CI: 0.62-0.96). At a 10% false-positive rate, first-trimester MAP could have predicted 39% of GH, 34% of term PE, 48% of preterm PE and 60% of EO-PE. The addition of maternal characteristics improved the predictive values (to 40%, 37%, 55% and 70%, respectively). First-trimester MAP is a strong predictor of GH and PE in nulliparous women. Copyright © 2017 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.

NO-dependent blood pressure regulation in RGS2-deficient mice

PubMed Central

Obst, Michael; Tank, Jens; Plehm, Ralph; Blumer, Kendall J.; Diedrich, Andrè; Jordan, Jens; Luft, Friedrich C.; Gross, Volkmar

2009-01-01

The regulator of G protein signaling (RGS) 2, a GTPase-activating protein, is activated via the nitric oxide (NO)-cGMP pathway and thereby may influence blood pressure regulation. To test that notion, we measured mean arterial blood pressure (MAP) and heart rate (HR) with telemetry in Nω-nitro-L-arginine methyl ester (L-NAME, 5 mg L-NAME/10 ml tap water)-treated RGS2-deficient (RGS2−/−) and RGS2-sufficient (RGS2+/+) mice and assessed autonomic function. Without L-NAME, RGS2−/− mice showed during day and night a similar increase of MAP compared with controls. L-NAME treatment increased MAP in both strains. nNOS is involved in this L-NAME-dependent blood pressure increase, since 7-nitroindazole increased MAP by 8 and 9 mmHg (P < 0.05) in both strains. The L-NAME-induced MAP increase of 14–15 mmHg during night was similar in both strains. However, the L-NAME-induced MAP increase during the day was smaller in RGS2−/− than in RGS2+/+ (11 ± 1 vs. 17 ± 2 mmHg; P < 0.05). Urinary norepinephrine and epinephrine excretion was higher in RGS2−/− than in RGS2+/+ mice. The MAP decrease after prazosin was more pronounced in L-NAME-RGS2−/−. HR variability parameters [root mean square of successive differences (RMSSD), low-frequency (LF) power, and high-frequency (HF) power] and baroreflex sensitivity were increased in RGS2−/−. Atropine and atropine plus metoprolol markedly reduced RMSSD, LF, and HF. Our data suggest an interaction between RGS2 and the NO-cGMP pathway. The blunted L-NAME response in RGS2−/− during the day suggests impaired NO signaling. The MAP increases during the active phase in RGS2−/− mice may be related to central sympathetic activation and increased vascular adrenergic responsiveness. PMID:16269576

System and method for bidirectional flow and controlling fluid flow in a conduit

DOEpatents

Ortiz, Marcos German

1999-01-01

A system for measuring bidirectional flow, including backflow, of fluid in a conduit. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit.

Acrylamide inhibits cellular differentiation of human neuroblastoma and glioblastoma cells.

PubMed

Chen, Jong-Hang; Chou, Chin-Cheng

2015-08-01

This study explores human neuroblastoma (SH-SY5Y) and human glioblastoma (U-1240 MG) cellular differentiation changes under exposure to acrylamide (ACR). Differentiation of SH-SY5Y and U-1240 MG cells were induced by retinoic acid (RA) and butyric acid (BA), respectively. Morphological observations and MTT assay showed that the induced cellular differentiation and cell proliferation were inhibited by ACR in a time- and dose-dependent manner. ACR co-treatment with RA attenuated SH-SY5Y expressions of neurofilament protein-L (NF-L), microtubule-associated protein 1b (MAP1b; 1.2 to 0.7, p < 0.001), MAP2c (2.2 to 0.8, p < 0.05), and Janus kinase1 (JAK1; 1.9 to 0.6, p < 0.001), while ACR co-treatment with BA attenuated U-1240 MG expressions of glial fibrillary acidic protein (GFAP), MAP1b (1.2 to 0.6, p < 0.001), MAP2c (1.5 to 0.7, p < 0.01), and JAK1 (2.1 to 0.5, p < 0.001), respectively. ACR also decreased the phosphorylation of extracellular-signal-regulated kinases (ERK) and c-Jun N-terminal kinases (JNK) in U-1240 MG cells, while caffeine reversed this suppression of ERK and JNK phosphorylation caused by ACR treatment. These results showed that RA-induced neurogenesis of SH-SY5Y and BA-induced astrogliogenesis of U-1240 MG cells were attenuated by ACR and were associated with down-regulation of MAPs expression and JAK-STAT signaling. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Impact of the Measures of Academic Progress (MAP) Program on Student Reading Achievement

ERIC Educational Resources Information Center

Cordray, David S.; Pion, Georgine M.; Brandt, Chris; Molefe, Ayrin

2013-01-01

One of the most widely used commercially available systems incorporating benchmark assessment and training in differentiated instruction is the Northwest Evaluation Association's (NWEA) Measures of Academic Progress (MAP) program. The MAP program involves two components: (1) computer-adaptive assessments administered to students three to four…

Differential 3D Mueller-matrix mapping of optically anisotropic depolarizing biological layers

NASA Astrophysics Data System (ADS)

Ushenko, O. G.; Grytsyuk, M.; Ushenko, V. O.; Bodnar, G. B.; Vanchulyak, O.; Meglinskiy, I.

2018-01-01

The paper consists of two parts. The first part is devoted to the short theoretical basics of the method of differential Mueller-matrix description of properties of partially depolarizing layers. It was provided the experimentally measured maps of differential matrix of the 2nd order of polycrystalline structure of the histological section of rectum wall tissue. It was defined the values of statistical moments of the1st-4th orders, which characterize the distribution of matrix elements. In the second part of the paper it was provided the data of statistic analysis of birefringence and dichroism of the histological sections of connecting component of vagina wall tissue (normal and with prolapse). It were defined the objective criteria of differential diagnostics of pathologies of vagina wall.

Transducer with a sense of touch

NASA Technical Reports Server (NTRS)

Bejczy, A. K.; Paine, G.

1979-01-01

Matrix of pressure sensors determines shape and pressure distribution of object in contact with its surface. Output can be used to develop pressure map of objects' surface and displayed as array of alphanumeric symbols on video monitor.

49 CFR 173.167 - Consumer commodities.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-toxic aerosols only), Class 3 (Packing Group II and III only), Division 6.1 (Packing Group III only.... Additionally, except for the pressure differential requirements in § 173.27(c), the requirements of § 173.27 do... appropriate, in accordance with subpart E of part 172 of this subchapter; and (2) Pressure differential...

Correlation of Noninvasive Blood Pressure and Invasive Intra-arterial Blood Pressure in Patients Treated with Vasoactive Medications in a Neurocritical Care Unit.

PubMed

Saherwala, Ali A; Stutzman, Sonja E; Osman, Mohamed; Kalia, Junaid; Figueroa, Stephen A; Olson, DaiWai M; Aiyagari, Venkatesh

2018-03-22

The correlation between noninvasive (oscillometric) blood pressure (NBP) and intra-arterial blood pressure (IAP) in critically ill patients receiving vasoactive medications in a Neurocritical Care Unit has not been systematically studied. The purpose of this study is to examine the relationship between simultaneously measured NBP and IAP recordings in these patients. Prospective observational study of patients (N = 70) admitted to a neurocritical care unit receiving continuous vasopressor or antihypertensive infusions. Paired NBP/IAP observations along with covariate and demographic data were abstracted via chart audit. Analysis was performed using SAS v9.4. A total of 2177 paired NBP/IAP observations from 70 subjects (49% male, 63% white, mean age 59 years) receiving vasopressors (n = 21) or antihypertensive agents (n = 49) were collected. Paired t test analysis showed significant differences between NBP versus IAP readings: ([systolic blood pressure (SBP): mean = 136 vs. 140 mmHg; p < 0.0001], [diastolic blood pressure (DBP): mean = 70 vs. 68 mmHg, p < 0.0001], [mean arterial blood pressure (MAP): mean = 86 vs. 90 mmHg, p < 0.0001]). Bland-Altman plots for MAP, SBP, and DBP demonstrate good inter-method agreement between paired measures (excluding outliers) and demonstrate NBP-IAP SBP differences at extremes of blood pressures. Pearson correlation coefficients show strong positive correlations for paired MAP (r = 0.82), SBP (r = 0.84), and DBP (r = 0.73) recordings. An absolute NBP-IAP SBP difference of > 20 mmHg was seen in ~ 20% of observations of nicardipine, ~ 25% of observations of norepinephrine, and ~ 35% of observations of phenylephrine. For MAP, the corresponding numbers were ~ 10, 15, and 25% for nicardipine, norepinephrine, and phenylephrine, respectively. Despite overall strong positive correlations between paired NBP and IAP readings of MAP and SBP, clinically relevant differences in blood pressure are frequent. When treating with vasoactive infusions targeted to a specific BP goal, it is important to keep in mind that NBP and IAP values are not interchangeable.

Childhood physical abuse predicts stressor-evoked activity within central visceral control regions

PubMed Central

Sheu, Lei K.; Midei, Aimee J.; Gianaros, Peter J.

2015-01-01

Early life experience differentially shapes later stress reactivity, as evidenced by both animal and human studies. However, early experience-related changes in the function of central visceral neural circuits that control stress responses have not been well characterized, particularly in humans. The paraventricular nucleus of the hypothalamus (PVN), bed nucleus of the stria terminalis (BNST), amygdala (Amyg) and subgenual anterior cingulate cortex (sgACC) form a core visceral stress-responsive circuit. The goal of this study is to examine how childhood emotional and physical abuse relates to adulthood stressor-evoked activity within these visceral brain regions. To evoke acute states of mental stress, participants (n = 155) performed functional magnetic resonance imaging (fMRI)-adapted versions of the multi-source interference task (MSIT) and the Stroop task with simultaneous monitoring of mean arterial pressure (MAP) and heart rate. Regression analyses revealed that childhood physical abuse correlated positively with stressor-evoked changes in MAP, and negatively with unbiased, a priori extractions of fMRI blood-oxygen level-dependent signal change values within the sgACC, BNST, PVN and Amyg (n = 138). Abuse-related changes in the function of visceral neural circuits may reflect neurobiological vulnerability to adverse health outcomes conferred by early adversity. PMID:24847113

Bond-selective imaging of deep tissue through the optical window between 1600 and 1850 nm.

PubMed

Wang, Pu; Wang, Han-Wei; Sturek, Michael; Cheng, Ji-Xin

2012-01-01

We report the employment of an optical window between 1600 nm and 1850 nm for bond-selective deep tissue imaging through harmonic vibrational excitation and acoustic detection of resultant pressure waves. In this window where a local minimum of water absorption resides, we found a 5 times enhancement of photoacoustic signal by first overtone excitation of the methylene group CH(2) at 1730 nm, compared to the second overtone excitation at 1210 nm. The enhancement allows 3D mapping of intramuscular fat with improved contrast and of lipid deposition inside an atherosclerotic artery wall in the presence of blood. Moreover, lipid and protein are differentiated based on the first overtone absorption profiles of CH(2) and methyl group CH(3) in this window. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interaction between graviception and carotid baroreflex function in humans during parabolic flight-induced microgravity.

PubMed

Ogoh, Shigehiko; Marais, Michaël; Lericollais, Romain; Denise, Pierre; Raven, Peter B; Normand, Hervé

2018-05-10

The aim of the present study was to assess carotid baroreflex (CBR) during acute changes in otolithic activity in humans. To address this question, we designed a set of experiments to identify the modulatory effects of microgravity on CBR function at a tilt angle of -2{degree sign}, which was identified to minimize changes in central blood volume during parabolic flight. During parabolic flight at 0g and 1g, CBR function curves were modelled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid pulse trains of neck pressure (NP) and neck suction (NS) ranging from +40 to -80 Torr; CBR control of HR (carotid-HR) and MAP (carotid-MAP) baroreflex function curves, respectively. The maximal gain (G max ) of both carotid-HR and carotid-MAP baroreflex function curves were augmented during microgravity compared to 1g (carotid-HR, -0.53 to -0.80 beats/min/mmHg, P<0.05; carotid-MAP, -0.24 to -0.30 mmHg/mmHg, P<0.05). These findings suggest that parabolic flight-induced acute change of otolithic activity may modify CBR function and identifies that the vestibular system contributes to blood pressure regulation under fluctuations in gravitational forces.

Low-Pressure Generator Makes Cleanrooms Cleaner

NASA Technical Reports Server (NTRS)

2005-01-01

Scientists at NASA's Kennedy Space Center work in cleanrooms: laboratories with high degrees of cleanliness provided by strict control of particles such as dust, lint, or human skin. They are contaminant-free facilities, where the air is repeatedly filtered, and surfaces are smooth to prevent particles from getting lodged. Technicians working in these environments wear specially designed cleanroom "bunny suits" and booties over their street clothes, as well as gloves and face masks to avoid any contamination that may be imparted from the outside world. Even normal paper is not allowed in cleanrooms, only cleanroom low-particulate paper. These are sensitive environments where precision work, like the production of silicon chips or hard disk drives, is performed. Often in cleanrooms, positive air pressure is used to force particles outside of the isolated area. The air pressure in the Kennedy cleanrooms is monitored using high-accuracy, low-differential pressure transducers that require periodic calibration. Calibration of the transducers is a tricky business. In prior years, the analysis was performed by sending the transducers to the Kennedy Standards Laboratory, where a very expensive cross-floated, labor- intensive, dead-weight test was conducted. In the early 1990s, scientists at Kennedy determined to develop a technique and find equipment to perform qualification testing on new low-differential pressure transducers in an accurate, cost-effective manner onsite, without requiring an environmentally controlled room. They decided to use the highly accurate, cost-effective Setra Model C264 as the test transducer. For qualification testing of the Setra, though, a portable, lower-cost calibrator was needed that could control the differential pressure to a high degree of resolution and transfer the accuracy of the Standards Laboratory testing to the qualification testing. The researchers decided that, to generate the low-differential pressure setpoints needed for qualification testing, very small gas volume changes could be made against the test article, and a corresponding pressure change would be detected by a pressure standard. This allowed the researchers to recreate cleanroom air pressure settings without the use of a cleanroom. Thus was born the low-differential pressure generator. In 1993, a prototype was developed using a pair of PVC tanks, a volume controller, and a 1-pound-per-square-inch pressure standard. By 1995, the prototype was perfected into the unit that is still used today.

Continuous hydrostatic pressure induces differentiation phenomena in chondrocytes mediated by changes in polycystins, SOX9, and RUNX2.

PubMed

Karamesinis, Konstantinos; Spyropoulou, Anastasia; Dalagiorgou, Georgia; Katsianou, Maria A; Nokhbehsaim, Marjan; Memmert, Svenja; Deschner, James; Vastardis, Heleni; Piperi, Christina

2017-01-01

The present study aimed to investigate the long-term effects of hydrostatic pressure on chondrocyte differentiation, as indicated by protein levels of transcription factors SOX9 and RUNX2, on transcriptional activity of SOX9, as determined by pSOX9 levels, and on the expression of polycystin-encoding genes Pkd1 and Pkd2. ATDC5 cells were cultured in insulin-supplemented differentiation medium (ITS) and/or exposed to 14.7 kPa of hydrostatic pressure for 12, 24, 48, and 96 h. Cell extracts were assessed for SOX9, pSOX9, and RUNX2 using western immunoblotting. The Pkd1 and Pkd2 mRNA levels were detected by real-time PCR. Hydrostatic pressure resulted in an early drop in SOX9 and pSOX9 protein levels at 12 h followed by an increase from 24 h onwards. A reverse pattern was followed by RUNX2, which reached peak levels at 24 h of hydrostatic pressure-treated chondrocytes in ITS culture. Pkd1 and Pkd2 mRNA levels increased at 24 h of combined hydrostatic pressure and ITS treatment, with the latter remaining elevated up to 96 h. Our data indicate that long periods of continuous hydrostatic pressure stimulate chondrocyte differentiation through a series of molecular events involving SOX9, RUNX2, and polycystins-1, 2, providing a theoretical background for functional orthopedic mechanotherapies.

Seismological Signature of Chemical Differentiation of Earth's Upper Mantle

NASA Astrophysics Data System (ADS)

Matsukage, K. N.; Nishihara, Y.; Karato, S.

2004-12-01

Chemical differentiation from a primitive rock (such as pyrolite) to harzburgite due to partial melting and melt extraction is one of the most important mechanisms that causes the chemical heterogeneity in Earth's upper mantle. In this study, we investigate the seismic signature of chemical differentiation that helps mapping chemical heterogeneity in the upper mantle. The relation between chemical differentiation and its seismological signature is not straightforward because a large number of unknown parameters are involved although the seismological observations provide only a few parameters (e.g., VP, VS, QP). Therefore it is critical to identify a small number of parameters by which the gross trend of chemical evolution can be described. The variation in major element composition in natural samples reflect complicated processes that include not only partial melting but also other complex processes (e.g., metasomatism, influx melting). We investigate the seismic velocities of hypothetical but well-defined simple chemical differentiation processes (e.g., partial melting of various pressure conditions, addition of Si-rich melt or fluid), which cover the chemical variation of the natural mantle peridotites with various tectonic settings (mid ocean ridge, island arc and continent). The seismic velocities of the peridotites were calculated to 13 GPa and 1730 K. We obtained two major conclusions. First is that the variations of seismic velocities of upper mantle peridotites can be interpreted in terms of a few distinct parameters. For one class of peridotites which is formed by simple partial melting (e.g. mid-ocean ridges peridotites), seismic velocities can be described in terms of one parameter, namely Mg# (=Mg/(Mg+Fe) atomic ratio). In contrast, some of the peridotites in the continental (cratonic) environment with high silica content and high Mg# need at least two parameters (such as Mg# and Opx# (the volume fraction of orthopyroxene)) are needed to characterize their seismic velocities. Second is the jump of seismic velocity at 300 km in harzburgite that is caused by orthorhombic (opx) to high-pressure monoclinic phase transition in MgSiO3 pyroxene. If opx-rich harzburgite (the maximum content of opx in continental harzburgite is ˜45 vol%) exists at around 300km, the maximum contrast of jump would be 2.5 % for VS and 0.9 % for VP. This phase transition will correspond to the seismological discontinuity around 300km (X-discontinuity).

Microtubule-dependent distribution of mRNA in adult cardiocytes.

PubMed

Scholz, Dimitri; Baicu, Catalin F; Tuxworth, William J; Xu, Lin; Kasiganesan, Harinath; Menick, Donald R; Cooper, George

2008-03-01

Synthesis of myofibrillar proteins in the diffusion-restricted adult cardiocyte requires microtubule-based active transport of mRNAs as part of messenger ribonucleoprotein particles (mRNPs) to translation sites adjacent to nascent myofibrils. This is especially important for compensatory hypertrophy in response to hemodynamic overloading. The hypothesis tested here is that excessive microtubule decoration by microtubule-associated protein 4 (MAP4) after cardiac pressure overloading could disrupt mRNP transport and thus hypertrophic growth. MAP4-overexpressing and pressure-overload hypertrophied adult feline cardiocytes were infected with an adenovirus encoding zipcode-binding protein 1-enhanced yellow fluorescent protein fusion protein, which is incorporated into mRNPs, to allow imaging of these particles. Speed and distance of particle movement were measured via time-lapse microscopy. Microtubule depolymerization was used to study microtubule-based transport and distribution of mRNPs. Protein synthesis was assessed as radioautographic incorporation of [3H]phenylalanine. After microtubule depolymerization, mRNPs persist only perinuclearly and apparent mRNP production and protein synthesis decrease. Reestablishing microtubules restores mRNP production and transport as well as protein synthesis. MAP4 overdecoration of microtubules via adenovirus infection in vitro or following pressure overloading in vivo reduces the speed and average distance of mRNP movement. Thus cardiocyte microtubules are required for mRNP transport and structural protein synthesis, and MAP4 decoration of microtubules, whether directly imposed or accompanying pressure-overload hypertrophy, causes disruption of mRNP transport and protein synthesis. The dense, highly MAP4-decorated microtubule network seen in severe pressure-overload hypertrophy both may cause contractile dysfunction and, perhaps even more importantly, may prevent a fully compensatory growth response to hemodynamic overloading.

Effects of pressure ulcer classification system education programme on knowledge and visual differential diagnostic ability of pressure ulcer classification and incontinence-associated dermatitis for clinical nurses in Korea.

PubMed

Lee, Yun Jin; Kim, Jung Yoon

2016-03-01

The objective of this study was to evaluate the effect of pressure ulcer classification system education on clinical nurses' knowledge and visual differential diagnostic ability of pressure ulcer (PU) classification and incontinence-associated dermatitis (IAD). One group pre and post-test was used. A convenience sample of 407 nurses, participating in PU classification education programme of continuing education, were enrolled. The education programme was composed of a 50-minute lecture on PU classification and case-studies. The PU Classification system and IAD knowledge test (PUCS-KT) and visual differential diagnostic ability tool (VDDAT), consisting of 21 photographs including clinical information were used. Paired t-test was performed using SPSS/WIN 20.0. The overall mean difference of PUCS-KT (t = -11·437, P<0·001) and VDDAT (t = -21·113, P<0·001) was significantly increased after PU classification education. Overall understanding of six PU classification and IAD after education programme was increased, but lacked visual differential diagnostic ability regarding Stage III PU, suspected deep tissue injury (SDTI), and Unstageable. Continuous differentiated education based on clinical practice is needed to improve knowledge and visual differential diagnostic ability for PU classification, and comparison experiment study is required to examine effects of education programmes. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

PubMed

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-07-22

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor

PubMed Central

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-01-01

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations. PMID:27455271

ROLE OF PRESSURE IN SMECTITE DEHYDRATION - EFFECTS ON GEOPRESSURE AND SMECTITE-TO-ILLITE TRANSFORMATION.

USGS Publications Warehouse

Colten-Bradley, Virginia

1987-01-01

Evaluation of the effects of pressure on the temperature of interlayer water loss (dehydration) by smectites under diagenetic conditions indicates that smectites are stable as hydrated phases in the deep subsurface. Hydraulic and differential pressure conditions affect dehydration differently. The temperature of dehydration increase with pore fluid pressure and interlayer water density. The temperatures of dehydration increase with pore fluid pressure and interlayer water density. The temperatures of dehydration under differential-presssure conditions are inversely related to pressure and interlayer water density. The model presented assumes the effects of pore fluid composition and 2:1 layer reactivity to be negligible. Agreement between theoretical and experimental results validate this assumption. Additional aspects of the subject are discussed.

Variable pressure ionization detector for gas chromatography

DOEpatents

Buchanan, Michelle V.; Wise, Marcus B.

1988-01-01

Method and apparatus for differentiating organic compounds based on their electron affinity. An electron capture detector cell (ECD) is operated at pressures ranging from atmospheric to less than 1 torr. Through variation of the pressure within the ECD cell, the organic compounds are induced to either capture or emit electrons. Differentiation of isomeric compounds can be obtianed when, at a given pressure, one isomer is in the emission mode and the other is in the capture mode. Output of the ECD is recorded by chromatogram. The invention also includes a method for obtaining the zero-crossing pressure of a compound, defined as the pressure at which the competing emission and capture reactions are balanced and which may be correlated to the electron affinity of a compound.

Mechanisms underlying the biphasic effect of vitamin K1 (phylloquinone) on arterial blood pressure.

PubMed

Tirapelli, Carlos R; Resstel, Leonardo B M; de Oliveira, Ana M; Corrêa, Fernando M A

2008-07-01

Phylloquinone (vitamin K(1), VK(1)) is widely used therapeutically and intravenous administration of this quinone can induce hypotension. We aimed to investigate the mechanisms underlying the effects induced by VK(1) on arterial blood pressure. With this purpose a catheter was inserted into the abdominal aorta of male Wistar rats for blood pressure and heart rate recording. Bolus intravenous injection of VK(1) (0.5-20 mgkg(-1)) produced a transient increase in blood pressure followed by a fall. Both the pressor and depressor response induced by VK(1) were dose-dependent. On the other hand, intravenous injection of VK(1) did not alter heart rate. The nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 10 and 20 mgkg(-1)) reduced both the increase and decrease in blood pressure induced by VK(1) (5 mgkg(-1)). On the other hand, indometacin (10 mg kg(-1)), a non-selective cyclooxygenase inhibitor, did not alter the increase in mean arterial pressure (MAP) induced by VK(1). However, VK(1)-induced fall in MAP was significantly attenuated by indometacin. We concluded that VK(1) induces a dose-dependent effect on blood pressure that consists of an acute increase followed by a more sustained decrease in MAP. The hypotension induced by VK(1) involves the activation of the nitric oxide (NO) pathway and the release of vasodilator prostanoid(s).

Fast neutron background characterization with the Radiological Multi-sensor Analysis Platform (RadMAP)

DOE PAGES

Davis, John R.; Brubaker, Erik; Vetter, Kai

2017-03-29

In an effort to characterize the fast neutron radiation background, 16 EJ-309 liquid scintillator cells were installed in the Radiological Multi-sensor Analysis Platform (RadMAP) to collect data in the San Francisco Bay Area. Each fast neutron event was associated with specific weather metrics (pressure, temperature, absolute humidity) and GPS coordinates. Furthermore, the expected exponential dependence of the fast neutron count rate on atmospheric pressure was demonstrated and event rates were subsequently adjusted given the measured pressure at the time of detection. Pressure adjusted data was also used to investigate the influence of other environmental conditions on the neutron background rate.more » Using National Oceanic and Atmospheric Administration (NOAA) coastal area lidar data, an algorithm was implemented to approximate sky-view factors (the total fraction of visible sky) for points along RadMAPs route. In the three areas we analyzed, San Francisco, Downtown Oakland, and Berkeley, all demonstrated a suppression in the background rate of over 50% for the range of sky-view factors measured. This effect, which is due to the shielding of cosmic-ray produced neutrons by surrounding buildings, was comparable to the pressure influence which yielded a 32% suppression in the count rate over the range of pressures measured.« less

Stretchable energy-harvesting tactile electronic skin capable of differentiating multiple mechanical stimuli modes.

PubMed

Park, Steve; Kim, Hyunjin; Vosgueritchian, Michael; Cheon, Sangmo; Kim, Hyeok; Koo, Ja Hoon; Kim, Taeho Roy; Lee, Sanghyo; Schwartz, Gregory; Chang, Hyuk; Bao, Zhenan

2014-11-19

The first stretchable energy-harvesting electronic-skin device capable of differentiating and generating energy from various mechanical stimuli, such as normal pressure, lateral strain, bending, and vibration, is presented. A pressure sensitivity of 0.7 kPa(-1) is achieved in the pressure region <1 kPa with power generation of tens of μW cm(-2) from a gentle finger touch. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study on Temperature and Synthetic Compensation of Piezo-Resistive Differential Pressure Sensors by Coupled Simulated Annealing and Simplex Optimized Kernel Extreme Learning Machine

PubMed Central

Li, Ji; Hu, Guoqing; Zhou, Yonghong; Zou, Chong; Peng, Wei; Alam SM, Jahangir

2017-01-01

As a high performance-cost ratio solution for differential pressure measurement, piezo-resistive differential pressure sensors are widely used in engineering processes. However, their performance is severely affected by the environmental temperature and the static pressure applied to them. In order to modify the non-linear measuring characteristics of the piezo-resistive differential pressure sensor, compensation actions should synthetically consider these two aspects. Advantages such as nonlinear approximation capability, highly desirable generalization ability and computational efficiency make the kernel extreme learning machine (KELM) a practical approach for this critical task. Since the KELM model is intrinsically sensitive to the regularization parameter and the kernel parameter, a searching scheme combining the coupled simulated annealing (CSA) algorithm and the Nelder-Mead simplex algorithm is adopted to find an optimal KLEM parameter set. A calibration experiment at different working pressure levels was conducted within the temperature range to assess the proposed method. In comparison with other compensation models such as the back-propagation neural network (BP), radius basis neural network (RBF), particle swarm optimization optimized support vector machine (PSO-SVM), particle swarm optimization optimized least squares support vector machine (PSO-LSSVM) and extreme learning machine (ELM), the compensation results show that the presented compensation algorithm exhibits a more satisfactory performance with respect to temperature compensation and synthetic compensation problems. PMID:28422080

Hydrostatic pressure enhances chondrogenic differentiation of human bone marrow stromal cells in osteochondrogenic medium.

PubMed

Wagner, Diane R; Lindsey, Derek P; Li, Kelvin W; Tummala, Padmaja; Chandran, Sheena E; Smith, R Lane; Longaker, Michael T; Carter, Dennis R; Beaupre, Gary S

2008-05-01

This study demonstrated the chondrogenic effect of hydrostatic pressure on human bone marrow stromal cells (MSCs) cultured in a mixed medium containing osteogenic and chondrogenic factors. MSCs seeded in type I collagen sponges were exposed to 1 MPa of intermittent hydrostatic pressure at a frequency of 1 Hz for 4 h per day for 10 days, or remained in identical culture conditions but without exposure to pressure. Afterwards, we compared the proteoglycan content of loaded and control cell/scaffold constructs with Alcian blue staining. We also used real-time PCR to evaluate the change in mRNA expression of selected genes associated with chondrogenic and osteogenic differentiation (aggrecan, type I collagen, type II collagen, Runx2 (Cbfa-1), Sox9, and TGF-beta1). With the hydrostatic pressure loading regime, proteoglycan staining increased markedly. Correspondingly, the mRNA expression of chondrogenic genes such as aggrecan, type II collagen, and Sox9 increased significantly. We also saw a significant increase in the mRNA expression of type I collagen, but no change in the expression of Runx2 or TGF-beta1 mRNA. This study demonstrated that hydrostatic pressure enhanced differentiation of MSCs in the presence of multipotent differentiation factors in vitro, and suggests the critical role that this loading regime may play during cartilage development and regeneration in vivo.

Study on Temperature and Synthetic Compensation of Piezo-Resistive Differential Pressure Sensors by Coupled Simulated Annealing and Simplex Optimized Kernel Extreme Learning Machine.

PubMed

Li, Ji; Hu, Guoqing; Zhou, Yonghong; Zou, Chong; Peng, Wei; Alam Sm, Jahangir

2017-04-19

As a high performance-cost ratio solution for differential pressure measurement, piezo-resistive differential pressure sensors are widely used in engineering processes. However, their performance is severely affected by the environmental temperature and the static pressure applied to them. In order to modify the non-linear measuring characteristics of the piezo-resistive differential pressure sensor, compensation actions should synthetically consider these two aspects. Advantages such as nonlinear approximation capability, highly desirable generalization ability and computational efficiency make the kernel extreme learning machine (KELM) a practical approach for this critical task. Since the KELM model is intrinsically sensitive to the regularization parameter and the kernel parameter, a searching scheme combining the coupled simulated annealing (CSA) algorithm and the Nelder-Mead simplex algorithm is adopted to find an optimal KLEM parameter set. A calibration experiment at different working pressure levels was conducted within the temperature range to assess the proposed method. In comparison with other compensation models such as the back-propagation neural network (BP), radius basis neural network (RBF), particle swarm optimization optimized support vector machine (PSO-SVM), particle swarm optimization optimized least squares support vector machine (PSO-LSSVM) and extreme learning machine (ELM), the compensation results show that the presented compensation algorithm exhibits a more satisfactory performance with respect to temperature compensation and synthetic compensation problems.

Quantitative validation of sensory mapping in persistent postherniorrhaphy inguinal pain patients undergoing triple neurectomy.

PubMed

Bjurström, M F; Álvarez, R; Nicol, A L; Olmstead, R; Amid, P K; Chen, D C

2017-04-01

Neurectomy of the inguinal nerves may be considered for selected refractory cases of chronic postherniorrhaphy inguinal pain (CPIP). There is to date a paucity of easily applicable clinical tools to identify neuropathic pain and examine the neurosensory effects of remedial surgery. The present quantitative sensory testing (QST) pilot study evaluates a sensory mapping technique. Longitudinal (preoperative, immediate postoperative, and late postoperative) dermatomal sensory mapping and a comprehensive QST protocol were conducted in CPIP patients with unilateral, predominantly neuropathic inguinodynia presenting for triple neurectomy (n = 13). QST was conducted in four areas on the affected, painful side and in one contralateral comparison site. QST variables were compared according to sensory mapping outcomes: (o)/normal sensation, (+)/pain, and (-)/numbness. Diagnostic ability of the sensory mapping outcomes to detect QST-assessed allodynia or hypoesthesia was estimated through calculation of specificity and sensitivity values. Preoperatively, patients exhibited mechanical hypoesthesia and allodynia and pressure allodynia and hyperalgesia in painful areas mapped (+) (p < .05); sensory mapping outcome (+) demonstrated high ability to detect mechanical allodynia [sensitivity 0.74 (95% CI 0.61-0.86), specificity 0.94 (0.84-1.00)] and pressure allodynia [sensitivity 0.96 (0.89-1.00), specificity 1.00 (1.00-1.00)], but not thermal allodynia. Postoperatively, mapped areas of numbness (-) were associated with mechanical and thermal hypoesthesia (p < .05); (-) showed high sensitivity and specificity to detect mechanical and cold hypoesthesia. Sensory mapping provides an accurate clinical neuropathic assessment with strong correlation to QST findings of preoperative mechanical and pressure allodynia, and postoperative mechanical and thermal hypoesthesia in CPIP patients undergoing neurectomy.

Significantly Reduced Blood Pressure Measurement Variability for Both Normotensive and Hypertensive Subjects: Effect of Polynomial Curve Fitting of Oscillometric Pulses

PubMed Central

Zhu, Mingping; Chen, Aiqing

2017-01-01

This study aimed to compare within-subject blood pressure (BP) variabilities from different measurement techniques. Cuff pressures from three repeated BP measurements were obtained from 30 normotensive and 30 hypertensive subjects. Automatic BPs were determined from the pulses with normalised peak amplitude larger than a threshold (0.5 for SBP, 0.7 for DBP, and 1.0 for MAP). They were also determined from cuff pressures associated with the above thresholds on a fitted curve polynomial curve of the oscillometric pulse peaks. Finally, the standard deviation (SD) of three repeats and its coefficient of variability (CV) were compared between the two automatic techniques. For the normotensive group, polynomial curve fitting significantly reduced SD of repeats from 3.6 to 2.5 mmHg for SBP and from 3.7 to 2.1 mmHg for MAP and reduced CV from 3.0% to 2.2% for SBP and from 4.3% to 2.4% for MAP (all P < 0.01). For the hypertensive group, SD of repeats decreased from 6.5 to 5.5 mmHg for SBP and from 6.7 to 4.2 mmHg for MAP, and CV decreased from 4.2% to 3.6% for SBP and from 5.8% to 3.8% for MAP (all P < 0.05). In conclusion, polynomial curve fitting of oscillometric pulses had the ability to reduce automatic BP measurement variability. PMID:28785580

Review of Cytoskeleton Research in Cell Differentiation and Development.

DTIC Science & Technology

1987-09-10

tetrameric mol- molecule and the corresponding site on ecule of dumbbell-like structure. Plec - ,MAP’s underwent molecular coevolution and tin’s globular...coworkers as plectin’s interaction by dlffe~ent MAP’s. Limited proteolysis partners. Thus, Wiche suggests that plec - of tubulin and MAP’s to analyze the

Evolution families of conformal mappings with fixed points and the Löwner-Kufarev equation

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

Goryainov, V V

2015-01-31

The paper is concerned with evolution families of conformal mappings of the unit disc to itself that fix an interior point and a boundary point. Conditions are obtained for the evolution families to be differentiable, and an existence and uniqueness theorem for an evolution equation is proved. A convergence theorem is established which describes the topology of locally uniform convergence of evolution families in terms of infinitesimal generating functions. The main result in this paper is the embedding theorem which shows that any conformal mapping of the unit disc to itself with two fixed points can be embedded into a differentiable evolution familymore » of such mappings. This result extends the range of the parametric method in the theory of univalent functions. In this way the problem of the mutual change of the derivative at an interior point and the angular derivative at a fixed point on the boundary is solved for a class of mappings of the unit disc to itself. In particular, the rotation theorem is established for this class of mappings. Bibliography: 27 titles.« less

Wiener filtering of the COBE Differential Microwave Radiometer data

NASA Technical Reports Server (NTRS)

Bunn, Emory F.; Fisher, Karl B.; Hoffman, Yehuda; Lahav, Ofer; Silk, Joseph; Zaroubi, Saleem

1994-01-01

We derive an optimal linear filter to suppress the noise from the cosmic background explorer satellite (COBE) Differential Microwave Radiometer (DMR) sky maps for a given power spectrum. We then apply the filter to the first-year DMR data, after removing pixels within 20 deg of the Galactic plane from the data. We are able to identify particular hot and cold spots in the filtered maps at a level 2 to 3 times the noise level. We use the formalism of constrained realizations of Gaussian random fields to assess the uncertainty in the filtered sky maps. In addition to improving the signal-to-noise ratio of the map as a whole, these techniques allow us to recover some information about the cosmic microwave background anisotropy in the missing Galactic plane region. From these maps we are able to determine which hot and cold spots in the data are statistically significant, and which may have been produced by noise. In addition, the filtered maps can be used for comparison with other experiments on similar angular scales.

Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer

NASA Technical Reports Server (NTRS)

Schofield, J. T.; Mccleese, Daniel J.

1988-01-01

An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

Pressure deformation of tires using differential stiffness for triangular solid-of-revolution elements

NASA Technical Reports Server (NTRS)

Chen, C. H. S.

1975-01-01

The derivation is presented of the differential stiffness for triangular solid of revolution elements. The derivation takes into account the element rigid body rotation only, the rotation being about the circumferential axis. Internal pressurization of a pneumatic tire is used to illustrate the application of this feature.

Pressure mapping and performance of the compression bandage/garment for venous leg ulcer treatment.

PubMed

Ghosh, S; Mukhopadhyay, A; Sikka, M; Nagla, K S

2008-08-01

A study has been conducted on the commercially available compression bandages as regards their performance with time. Pressure mapping of these bandages has been done using a fabricated pressure-measuring device on a mannequin leg to see the effect on pressure due to creep, fabric friction and angle of bandaging. The results show that the creep behavior, frictional behavior and the angle of bandaging have a significant effect on the pressure profile generated by the bandages during application. The regression analysis shows that the surface friction restricts the slippage in a multilayer system. Also the diameters of the limb and the amount of stretch given to the bandage during application have definite impact on the bandage pressure. In case of compression garments, washing improves the pressure generated but not to the extent of the pressure of a virgin garment. Comparing the two compression materials i.e. bandage and garment, it is found that the presence of higher percentage of elastomeric material and a highly close construction in case of garment provides better holding power and a more homogeneous pressure distribution.

[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.

Theoretical Thermodynamics of Mixtures at High Pressures

NASA Technical Reports Server (NTRS)

Hubbard, W. B.

1985-01-01

The development of an understanding of the chemistry of mixtures of metallic hydrogen and abundant, higher-z material such as oxygen, carbon, etc., is important for understanding of fundamental processes of energy release, differentiation, and development of atmospheric abundances in the Jovian planets. It provides a significant theoretical base for the interpretation of atmospheric elemental abundances to be provided by atmospheric entry probes in coming years. Significant differences are found when non-perturbative approaches such as Thomas-Fermi-Dirac (TFD) theory are used. Mapping of the phase diagrams of such binary mixtures in the pressure range from approx. 10 Mbar to approx. 1000 Mbar, using results from three-dimensional TFD calculations is undertaken. Derivation of a general and flexible thermodynamic model for such binary mixtures in the relevant pressure range was facilitated by the following breakthrough: there exists an accurate nd fairly simple thermodynamic representation of a liquid two-component plasma (TCP) in which the Helmholtz free energy is represented as a suitable linear combination of terms dependent only on density and terms which depend only on the ion coupling parameter. It is found that the crystal energies of mixtures of H-He, H-C, and H-O can be satisfactorily reproduced by the same type of model, except that an effective, density-dependent ionic charge must be used in place of the actual total ionic charge.

System and method for bidirectional flow and controlling fluid flow in a conduit

DOEpatents

Ortiz, M.G.

1999-03-23

A system for measuring bidirectional flow, including backflow, of fluid in a conduit is disclosed. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit. 3 figs.

Migration rates and formation injectivity to determine containment time scales of sequestered carbon dioxide

USGS Publications Warehouse

Burke, Lauri

2012-01-01

Additionally, this research establishes a methodology to calculate the injectivity of a target formation. Because injectivity describes the pressure increase due to the introduction of fluids into a formation, the relevant application of injectivity is to determine the pressure increase, due to an injection volume and flow rate, that will induce fractures in the reservoir rocks. This quantity is defined mathematically as the maximum pressure differential between the hydrostatic gradient and the fracture gradient of the target formation. Injectivity is mathematically related to the maximum pressure differential of the formation, and can be used to determine the upper limit for the pressure increase that an injection target can withstand before fracturing.

Rat Cardiovascular Responses to Whole Body Suspension: Head-down and Non-Head-Down Tilt

NASA Technical Reports Server (NTRS)

Musacchia, X. J.; Steffen, Joseph M.; Dombrowski, Judy

1992-01-01

The rat whole body suspension technique mimics responses seen during exposure to microgravity and was evaluated as a model for cardiovascular responses with two series of experiments. In one series, changes were monitored in chronically catheterized rats during 7 days of Head-Down Tilt (HDT) or Non-Head-Down Tilt (N-HDT) and after several hours of recovery. Elevations of mean arterial (MAP), systolic, and diastolic pressures of approx. 20 % (P less than 0.05) in HDT rats began as early as day 1 and were maintained for the duration of suspension. Pulse pressures were relatively unaffected, but heart rates were elevated approx. 10 %. During postsuspension (2-7 h), most cardiovascular parameters returned to presuspension levels. N-HDT rats exhibited elevations chiefly on days 3 and 7. In the second series, blood pressure was monitored in 1- and 3-day HDT and N-HDT rats to evaluate responses to rapid head-up tilt. MAP, systolic and diastolic pressures, and HR were elevated (P less than 0.05) in HDT and N-HDT rats during head-up tilt after 1 day of suspension, while pulse pressures remained un changed. HDT rats exhibited elevated pretilt MAP and failed to respond to rapid head-up tilt with further increase of MAP on day 3, indicating some degree of deconditioning. The whole body suspended rat may be useful as a model to better understand responses of rats exposed to microgravity.

Mueller matrix mapping of biological polycrystalline layers using reference wave

NASA Astrophysics Data System (ADS)

Dubolazov, A.; Ushenko, O. G.; Ushenko, Yu. O.; Pidkamin, L. Y.; Sidor, M. I.; Grytsyuk, M.; Prysyazhnyuk, P. V.

2018-01-01

The paper consists of two parts. The first part is devoted to the short theoretical basics of the method of differential Mueller-matrix description of properties of partially depolarizing layers. It was provided the experimentally measured maps of differential matrix of the 1st order of polycrystalline structure of the histological section of brain tissue. It was defined the statistical moments of the 1st-4th orders, which characterize the distribution of matrix elements. In the second part of the paper it was provided the data of statistic analysis of birefringence and dichroism of the histological sections of mice liver tissue (normal and with diabetes). It were defined the objective criteria of differential diagnostics of diabetes.

Differential Geometry and Lie Groups for Physicists

NASA Astrophysics Data System (ADS)

Fecko, Marián.

2006-10-01

Introduction; 1. The concept of a manifold; 2. Vector and tensor fields; 3. Mappings of tensors induced by mappings of manifolds; 4. Lie derivative; 5. Exterior algebra; 6. Differential calculus of forms; 7. Integral calculus of forms; 8. Particular cases and applications of Stoke's Theorem; 9. Poincaré Lemma and cohomologies; 10. Lie Groups - basic facts; 11. Differential geometry of Lie Groups; 12. Representations of Lie Groups and Lie Algebras; 13. Actions of Lie Groups and Lie Algebras on manifolds; 14. Hamiltonian mechanics and symplectic manifolds; 15. Parallel transport and linear connection on M; 16. Field theory and the language of forms; 17. Differential geometry on TM and T*M; 18. Hamiltonian and Lagrangian equations; 19. Linear connection and the frame bundle; 20. Connection on a principal G-bundle; 21. Gauge theories and connections; 22. Spinor fields and Dirac operator; Appendices; Bibliography; Index.

Differential Geometry and Lie Groups for Physicists

NASA Astrophysics Data System (ADS)

Fecko, Marián.

2011-03-01

Introduction; 1. The concept of a manifold; 2. Vector and tensor fields; 3. Mappings of tensors induced by mappings of manifolds; 4. Lie derivative; 5. Exterior algebra; 6. Differential calculus of forms; 7. Integral calculus of forms; 8. Particular cases and applications of Stoke's Theorem; 9. Poincaré Lemma and cohomologies; 10. Lie Groups - basic facts; 11. Differential geometry of Lie Groups; 12. Representations of Lie Groups and Lie Algebras; 13. Actions of Lie Groups and Lie Algebras on manifolds; 14. Hamiltonian mechanics and symplectic manifolds; 15. Parallel transport and linear connection on M; 16. Field theory and the language of forms; 17. Differential geometry on TM and T*M; 18. Hamiltonian and Lagrangian equations; 19. Linear connection and the frame bundle; 20. Connection on a principal G-bundle; 21. Gauge theories and connections; 22. Spinor fields and Dirac operator; Appendices; Bibliography; Index.

Arterial and intraocular pressure changes after a single-session hot-water immersion.

PubMed

Findikoglu, Gulin; Cetin, Ebru Nevin; Sarsan, Ayse; Senol, Hande; Yildirim, Cem; Ardic, Fusun

2015-01-01

The aim of this study is to investigate the effect of head-out hot-water immersion on the intraocular pressure (IOP) of healthy subjects and investigate whether this intervention alters cardiovascular and microcirculatory responses. METHODs: 16 male and 18 female healthy young adults were immersed in 39 degrees C water up to shoulder level for 20 minutes. Blood pressure (BP), heart rate (HR) and IOP were measured pre-immersion, post-immersion and five minutes after immersion on the same day. Tono-Pen was used to measure IOP. Mean arterial blood pressure (MAP), systolic pressure rate product (S-PRP), diastolic pressure rate product (D-PRP), pulse pressure (PP), mean ocular perfusion pressure (mean-OPP), systolic ocular perfusion pressure (S-OPP) and diastolic ocular perfusion pressure (D-OPP) were calculated. Systolic BP (SBP), diastolic BP (DBP), MAP, IOP, S-OPP, D-OPP and mean-OPP decreased; HR increased five minutes after immersion in the pool and post-immersion out of the pool significantly, compared to pre-immersion data (p < 0.05). HR, S-PRP and D-PRP measured five minutes after immersion were significantly higher from post-immersion (p < 0.05). PP and S-OPP were significantly different five minutes after immersion compared to pre-immersion. There was no statistically significant correlation between IOP and SBP, DBP, MAP, S-PRP, D-PRP, PP, S-OPP, D-OPP, or mean-OPP (p > 0.05). Physiological hemodynamic response to single head-out hot-water immersion caused a statistically significant decrease in IOP. Preliminary results could help to clarify vascular reactions and IOP changes during hot-water immersion that might be potentially therapeutic in glaucoma patients.

Investigation of the effects of extravehicular activity (EVA) gloves on performance

NASA Technical Reports Server (NTRS)

Bishu, Ram R.; Klute, Glenn

1993-01-01

The objective was to assess the effects of extravehicular activity (EVA) gloves at different pressures on human hand capabilities. A factorial experiment was performed in which three types of EVA gloves were tested at five pressure differentials. The independent variables tested in this experiment were gender, glove type, pressure differential, and glove make. Six subjects participated in an experiment where a number of dexterity measures, namely time to tie a rope, and the time to assemble a nut and bolt were recorded. Tactility was measured through a two point discrimination test. The results indicate that with EVA gloves strength is reduced by nearly 50 percent, there is a considerable reduction in dexterity, performance decrements increase with increasing pressure differential, and some interesting gender glove interactions were observed, some of which may have been due to the extent (or lack of) fit of the glove to the hand. The implications for the designer are discussed.

Evaluation of ERTS-1 imagery for mapping Quaternary deposits and landforms in the Great Plains and Midwest

NASA Technical Reports Server (NTRS)

Morrison, R. B. (Principal Investigator); Hallberg, G. R.

1973-01-01

The author has identified the following significant results. The main landform associations and larger landforms are readily identifiable on the better images and commonly the gross associations of surficial Quaternary deposits also can be differentiated, primarily by information on landforms and soils. Maps showing the Quaternary geologic-terrain units that can be differentiated from the ERTS-1 images are being prepared for study areas in Illinois, Iowa, Missouri, Kansas, Nebraska, and South Dakota. Preliminary maps at 1:1 million scale are given of two of the study areas, the Peoria and Decatur, Illinois, 1 deg x 2 quadrangles. These maps exemplify the first phase of investigations, which consists of identifying and mapping landform and land use characteristics and geologic-surficial materials directly from ERTS-1 images alone, without input of additional data. These maps shown that commonly the boundaries of geologic-terrain units can be identified more accurately on ERTS-1 images than on topographic maps of 1:250,000 scale. From analysis of drainage patterns, stream-divide relations, and tone and textural variations on the ERTS-1 images, the trends of numerous moraines of Wisconsinan and possibly some of Illinoian age were mapped. In the Peoria study area the trend of a buried valley of the Mississippi River is revealed.

Pressure Mapping Mat for Tele-Home Care Applications

PubMed Central

Saenz-Cogollo, Jose Francisco; Pau, Massimiliano; Fraboni, Beatrice; Bonfiglio, Annalisa

2016-01-01

In this paper we present the development of a mat-like pressure mapping system based on a single layer textile sensor and intended to be used in home environments for monitoring the physical condition of persons with limited mobility. The sensor is fabricated by embroidering silver-coated yarns on a light cotton fabric and creating pressure-sensitive resistive elements by stamping the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) at the crossing points of conductive stitches. A battery-operated mat prototype was developed and includes the scanning circuitry and a wireless communication module. A functional description of the system is presented together with a preliminary experimental evaluation of the mat prototype in the extraction of plantar pressure parameters. PMID:26978369

Relationship between glacier melting and atmospheric circulation in the southeast Siberia

NASA Astrophysics Data System (ADS)

Osipova, O. P.; Osipov, E. Y.

2018-01-01

The interaction between climate and cryosphere is a key issue in recent years. Changes in surface mass balance of mountain glaciers closely correspond to differential changes in atmospheric circulation. Mountain glaciers in southeast Siberia located on East Sayan, Baikalsky and Kodar ridges have been continuously shrinking since the end of the Little Ice Age. In this study we used daily synoptic weather maps (Irkutsk Center of Hydrometeorology and Environmental Monitoring), 500 hPa, 700 hPa and 850 hPa geopotential height and air temperature data of NCEP/NCAR reanalysis to assess relationships between atmospheric circulation patterns and the sum of positive temperature (SPT), a predictor of summer ice/snow ablation. Results show that increased SPT (ablation) is generally associated with anticyclones and anticyclonic pressure fields (with cloudless weather conditions) and warm atmospheric fronts. Decreased SPT (ablation) is strongly correlated with cyclones and cyclonic type pressure fields, cold atmospheric fronts and air advections. Significant correlations have been found between ablation and cyclonic/anticyclonic activity. Revealed decreasing trends in the SPT in three glaciarized ridges at the beginning of the 21st century led to changes of air temperature and snow/ice melt climates.

Mycobacterium avium subspecies paratuberculosis in bioaerosols after depopulation and cleaning of two cattle barns.

PubMed

Eisenberg, S; Nielen, M; Hoeboer, J; Bouman, M; Heederik, D; Koets, A

2011-06-04

Settled dust samples were collected on a commercial dairy farm in the Netherlands with a high prevalence of Mycobacterium avium subspecies paratuberculosis (MAP) (barn A) and on a Dutch experimental cattle farm (barn B) stocked with cattle confirmed to be MAP shedders. Barns were sampled while animals were present, after both barns were destocked and cleaned by cold high-pressure cleaning, and after being kept empty for two weeks (barn A) or after additional disinfection (barn B). MAP DNA was detected by IS900 real-time PCR and viable MAP were detected by liquid culture. MAP DNA was detected in 78 per cent of samples from barn A and 86 per cent of samples from barn B collected while animals were still present. Viable MAP was detected in six of nine samples from barn A and in three of seven samples from barn B. After cold high-pressure cleaning, viable MAP could be detected in only two samples from each barn. After leaving barn A empty for two weeks, and following additional disinfection of barn B, no viable MAP could be detected in any settled dust sample.

CdS nanorods/organic hybrid LED array and the piezo-phototronic effect of the device for pressure mapping.

PubMed

Bao, Rongrong; Wang, Chunfeng; Dong, Lin; Shen, Changyu; Zhao, Kun; Pan, Caofeng

2016-04-21

As widely applied in light-emitting diodes and optical devices, CdS has attracted the attention of many researchers due to its nonlinear properties and piezo-electronic effect. Here, we demonstrate a LED array composed of PSS and CdS nanorods and research the piezo-photonic effect of the array device. The emission intensity of the device depends on the electron-hole recombination at the interface of the p-n junction which can be adjusted using the piezo-phototronic effect and can be used to map the pressure applied on the surface of the device with spatial resolution as high as 1.5 μm. A flexible LED device array has been prepared using a CdS nanorod array on a Au/Cr/kapton substrate. This device may be used in the field of strain mapping using its high pressure spatial-resolution and flexibility.

Senses & Sensibility: Predator-Prey Experiments Reveal How Fish Perceive & Respond to Threats

ERIC Educational Resources Information Center

Jones, Jason; Holloway, Barbara; Ketcham, Elizabeth; Long, John

2008-01-01

The predator-prey relationship is one of the most recognizable and well-studied animal relationships. One of the more striking aspects of this relationship is the differential natural selection pressure placed on predators and their prey. This differential pressure results from differing costs of failure, the so-called life-dinner principle. If a…

Automated method to differentiate between native and mirror protein models obtained from contact maps.

PubMed

Kurczynska, Monika; Kotulska, Malgorzata

2018-01-01

Mirror protein structures are often considered as artifacts in modeling protein structures. However, they may soon become a new branch of biochemistry. Moreover, methods of protein structure reconstruction, based on their residue-residue contact maps, need methodology to differentiate between models of native and mirror orientation, especially regarding the reconstructed backbones. We analyzed 130 500 structural protein models obtained from contact maps of 1 305 SCOP domains belonging to all 7 structural classes. On average, the same numbers of native and mirror models were obtained among 100 models generated for each domain. Since their structural features are often not sufficient for differentiating between the two types of model orientations, we proposed to apply various energy terms (ETs) from PyRosetta to separate native and mirror models. To automate the procedure for differentiating these models, the k-means clustering algorithm was applied. Using total energy did not allow to obtain appropriate clusters-the accuracy of the clustering for class A (all helices) was no more than 0.52. Therefore, we tested a series of different k-means clusterings based on various combinations of ETs. Finally, applying two most differentiating ETs for each class allowed to obtain satisfying results. To unify the method for differentiating between native and mirror models, independent of their structural class, the two best ETs for each class were considered. Finally, the k-means clustering algorithm used three common ETs: probability of amino acid assuming certain values of dihedral angles Φ and Ψ, Ramachandran preferences and Coulomb interactions. The accuracies of clustering with these ETs were in the range between 0.68 and 0.76, with sensitivity and selectivity in the range between 0.68 and 0.87, depending on the structural class. The method can be applied to all fully-automated tools for protein structure reconstruction based on contact maps, especially those analyzing big sets of models.

Automated method to differentiate between native and mirror protein models obtained from contact maps

PubMed Central

Kurczynska, Monika

2018-01-01

Mirror protein structures are often considered as artifacts in modeling protein structures. However, they may soon become a new branch of biochemistry. Moreover, methods of protein structure reconstruction, based on their residue-residue contact maps, need methodology to differentiate between models of native and mirror orientation, especially regarding the reconstructed backbones. We analyzed 130 500 structural protein models obtained from contact maps of 1 305 SCOP domains belonging to all 7 structural classes. On average, the same numbers of native and mirror models were obtained among 100 models generated for each domain. Since their structural features are often not sufficient for differentiating between the two types of model orientations, we proposed to apply various energy terms (ETs) from PyRosetta to separate native and mirror models. To automate the procedure for differentiating these models, the k-means clustering algorithm was applied. Using total energy did not allow to obtain appropriate clusters–the accuracy of the clustering for class A (all helices) was no more than 0.52. Therefore, we tested a series of different k-means clusterings based on various combinations of ETs. Finally, applying two most differentiating ETs for each class allowed to obtain satisfying results. To unify the method for differentiating between native and mirror models, independent of their structural class, the two best ETs for each class were considered. Finally, the k-means clustering algorithm used three common ETs: probability of amino acid assuming certain values of dihedral angles Φ and Ψ, Ramachandran preferences and Coulomb interactions. The accuracies of clustering with these ETs were in the range between 0.68 and 0.76, with sensitivity and selectivity in the range between 0.68 and 0.87, depending on the structural class. The method can be applied to all fully-automated tools for protein structure reconstruction based on contact maps, especially those analyzing big sets of models. PMID:29787567

Invariants, Attractors and Bifurcation in Two Dimensional Maps with Polynomial Interaction

NASA Astrophysics Data System (ADS)

Hacinliyan, Avadis Simon; Aybar, Orhan Ozgur; Aybar, Ilknur Kusbeyzi

This work will present an extended discrete-time analysis on maps and their generalizations including iteration in order to better understand the resulting enrichment of the bifurcation properties. The standard concepts of stability analysis and bifurcation theory for maps will be used. Both iterated maps and flows are used as models for chaotic behavior. It is well known that when flows are converted to maps by discretization, the equilibrium points remain the same but a richer bifurcation scheme is observed. For example, the logistic map has a very simple behavior as a differential equation but as a map fold and period doubling bifurcations are observed. A way to gain information about the global structure of the state space of a dynamical system is investigating invariant manifolds of saddle equilibrium points. Studying the intersections of the stable and unstable manifolds are essential for understanding the structure of a dynamical system. It has been known that the Lotka-Volterra map and systems that can be reduced to it or its generalizations in special cases involving local and polynomial interactions admit invariant manifolds. Bifurcation analysis of this map and its higher iterates can be done to understand the global structure of the system and the artifacts of the discretization by comparing with the corresponding results from the differential equation on which they are based.

Separating myoblast differentiation from muscle cell fusion using IGF-I and the p38 MAP kinase inhibitor SB202190.

PubMed

Gardner, Samantha; Gross, Sean M; David, Larry L; Klimek, John E; Rotwein, Peter

2015-10-01

The p38 MAP kinases play critical roles in skeletal muscle biology, but the specific processes regulated by these kinases remain poorly defined. Here we find that activity of p38α/β is important not only in early phases of myoblast differentiation, but also in later stages of myocyte fusion and myofibrillogenesis. By treatment of C2 myoblasts with the promyogenic growth factor insulin-like growth factor (IGF)-I, the early block in differentiation imposed by the p38 chemical inhibitor SB202190 could be overcome. Yet, under these conditions, IGF-I could not prevent the later impairment of muscle cell fusion, as marked by the nearly complete absence of multinucleated myofibers. Removal of SB202190 from the medium of differentiating myoblasts reversed the fusion block, as multinucleated myofibers were detected several hours later and reached ∼90% of the culture within 30 h. Analysis by quantitative mass spectroscopy of proteins that changed in abundance following removal of the inhibitor revealed a cohort of upregulated muscle-enriched molecules that may be important for both myofibrillogenesis and fusion. We have thus developed a model system that allows separation of myoblast differentiation from muscle cell fusion and should be useful in identifying specific steps regulated by p38 MAP kinase-mediated signaling in myogenesis. Copyright © 2015 the American Physiological Society.

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.

New developments in cerebral blood flow autoregulation analysis in preterm infants: a mechanistic approach.

PubMed

Riera, Joan; Cabañas, Fernando; Serrano, José Javier; Madero, Rosario; Pellicer, Adelina

2016-03-01

Impaired autoregulation capacity implies that changes in cerebral perfusion follow changes in blood pressure; however, no analytical method has explored such a signal causality relationship in infants. We sought to develop a method to assess cerebral autoregulation from a mechanistic point of view and explored the predictive capacity of the method to classify infants at risk for adverse outcomes. The partial directed coherence (PDC) method, which considers synchronicity and directionality of signal dependence across frequencies, was used to analyze the relationship between spontaneous changes in mean arterial pressure (MAP) and the cerebral tissue oxygenation index (TOI). PDCMAP>TOI indicated that changes in TOI were induced by MAP changes, and PDCTOI>MAP indicated the opposite. The PDCMAP>TOI and PDCTOI>MAP values differed. PDCMAP>TOI adjusted by gestational age predicted low superior vena cava flow (≤41 ml/kg per min), with an area under the receiver operating characteristic curve of 0.72 (95% CI: 0.63-0.81; P < 0.001), whereas PDCTOI>MAP did not. The adjusted pPDCMAP>TOI (the average value per patient) predicted severe intracranial hemorrhage and mortality. PDCMAP>TOI allows for a noninvasive physiological interpretation of the pressure autoregulation process in neonates. PDCMAP>TOI is a good classifier for infants at risk of brain hypoperfusion and adverse outcomes.

Effect of Intensive Blood Pressure Control on Cardiovascular Remodeling in Hypertensive Patients with Nephrosclerosis

PubMed Central

Kwagyan, John; Pogue, Velvie; Xu, Shichen; Greene, Tom; Wang, Xuelei; Agodoa, Lawrence

2013-01-01

Pulse pressure (PP), a marker of arterial system properties, has been linked to cardiovascular (CV) complications. We examined (a) association between unit changes of PP and (i) composite CV outcomes and (ii) development of left-ventricular hypertrophy (LVH) and (b) effect of mean arterial pressure (MAP) control on rate of change in PP. We studied 1094 nondiabetics with nephrosclerosis in the African American Study of Kidney Disease and Hypertension. Subjects were randomly assigned to usual MAP goal (102–107 mmHg) or a lower MAP goal (≤92 mmHg) and randomized to beta-blocker, angiotensin converting enzyme inhibitor, or calcium channel blocker. After covariate adjustment, a higher PP was associated with increased risk of CV outcome (RR = 1.28, CI = 1.11–1.47, P < 0.01) and new LVH (RR = 1.26, CI = 1.04–1.54, P = 0.02). PP increased at a greater rate in the usual than in lower MAP groups (slope ± SE: 1.08 ± 0.15 versus 0.42 ± 0.15 mmHg/year, P = 0.002), but not by the antihypertensive treatment assignment. Observations indicate that control to a lower MAP slows the progression of PP, a correlate of cardiovascular remodeling and complications, and may be beneficial to CV health. PMID:24102027

Automatic transducer switching provides accurate wide range measurement of pressure differential

NASA Technical Reports Server (NTRS)

Yoder, S. K.

1967-01-01

Automatic pressure transducer switching network sequentially selects any one of a number of limited-range transducers as gas pressure rises or falls, extending the range of measurement and lessening the chances of damage due to high pressure.

Development of a Nutritional Delivery System to Feed Crew in a Pressurized Suit

NASA Technical Reports Server (NTRS)

Glass, J. W.; Leonig, M. L.; Douglas, G. L.

2014-01-01

The contingency scenario for an emergency cabin depressurization event may require crewmembers to subsist in a pressurized suit for up to 144 hours. This scenario requires the capability for safe nutrition delivery through a helmet feed port against a 4 psi pressure differential to enable crewmembers to maintain strength and cognition to perform critical tasks. Two nutritional delivery prototypes were developed and analyzed for compatibility with the helmet feed port interface and for operational effectiveness against the pressure differential. The bag-in-bag (BiB) prototype, designed to equalize the suit pressure with the beverage pouch and enable a crewmember to drink normally, delivered water successfully to three different subjects in suits pressurized to 4 psi. The Boa restrainer pouch, designed to provide mechanical leverage to overcome the pressure differential, did not operate sufficiently. Guidelines were developed and compiled for contingency beverages that provide macro-nutritional requirements, a minimum one-year shelf life, and compatibility with the delivery hardware. Evaluation results and food product parameters have the potential to be used to improve future prototype designs and develop complete nutritional beverages for contingency events. These feeding capabilities would have additional use on extended surface mission EVAs, where the current in-suit drinking device may be insufficient.

Tank depletion flow controller

DOEpatents

Georgeson, Melvin A.

1976-10-26

A flow control system includes two bubbler tubes installed at different levels within a tank containing such as radioactive liquid. As the tank is depleted, a differential pressure transmitter monitors pressure differences imparted by the two bubbler tubes at a remote, shielded location during uniform time intervals. At the end of each uniform interval, balance pots containing a dense liquid are valved together to equalize the pressures. The resulting sawtooth-shaped signal generated by the differential pressure transmitter is compared with a second sawtooth signal representing the desired flow rate during each time interval. Variations in the two signals are employed by a control instrument to regulate flow rate.

The effect of losartan on differential reflex control of sympathetic nerve activity in chronic kidney disease.

PubMed

Yao, Yimin; Hildreth, Cara M; Farnham, Melissa M; Saha, Manash; Sun, Qi-Jian; Pilowsky, Paul M; Phillips, Jacqueline K

2015-06-01

The effect of angiotensin II type I receptor (AT1R) inhibition on the pattern of reflex sympathetic nerve activity (SNA) to multiple target organs in the Lewis polycystic kidney (LPK) rat model of chronic kidney disease was determined. Mean arterial pressure (MAP), splanchnic SNA (sSNA), renal SNA (rSNA) and lumbar SNA (lSNA) were recorded in urethane-anaesthetized LPK and Lewis controls (total n = 39). Baroreflex, peripheral and central chemoreflex, and somatosensory reflex control of SNA (evoked by phenylephrine/sodium nitroprusside infusion, 10% O2 in N2 or 100% N2 ventilation, 5% CO2 ventilation and sciatic nerve stimulation, respectively) were determined before and after administration of losartan (AT1R antagonist 3 mg/kg, intravenous). Baseline MAP was higher in LPK rats and baroreflex control of sSNA and rSNA, but not lSNA, was reduced. Losartan reduced MAP in both strains and selectively improved baroreflex gain for sSNA (-1.2 ± 0.1 vs. -0.7 ± 0.07 %/mmHg; P < 0.05) in LPK. The peripheral and central chemoreflex increased MAP and all SNA in Lewis controls, but reduced or had no effect on these parameters, respectively, in LPK. The SNA response to somatosensory stimulation was biphasic, with latency to second peak less in LPK. Losartan ameliorated the depressor and sympathoinhibitory responses to peripheral chemoreflex stimulation in the LPK, but did not alter the central chemoreflex or somatosympathetic responses. Inhibition of the AT1R selectively improved baroreflex control of sSNA and peripheral chemoreflex control of all three sympathetic nerve outflows in the LPK rat, suggesting these anomalies in reflex function are driven in part by angiotensin II.

Suited Contingency Ops Food - 2

NASA Technical Reports Server (NTRS)

Glass, J. W.; Leong, M. L.; Douglas, G. L.

2014-01-01

The contingency scenario for an emergency cabin depressurization event may require crewmembers to subsist in a pressurized suit for up to 144 hours. This scenario requires the capability for safe nutrition delivery through a helmet feed port against a 4 psi pressure differential to enable crewmembers to maintain strength and cognition to perform critical tasks. Two nutritional delivery prototypes were developed and analyzed for compatibility with the helmet feed port interface and for operational effectiveness against the pressure differential. The bag-in-bag (BiB) prototype, designed to equalize the suit pressure with the beverage pouch and enable a crewmember to drink normally, delivered water successfully to three different subjects in suits pressurized to 4 psi. The Boa restrainer pouch, designed to provide mechanical leverage to overcome the pressure differential, did not operate sufficiently. Guidelines were developed and compiled for contingency beverages that provide macro-nutritional requirements, a minimum one-year shelf life, and compatibility with the delivery hardware. Evaluation results and food product parameters have the potential to be used to improve future prototype designs and develop complete nutritional beverages for contingency events. These feeding capabilities would have additional use on extended surface mission EVAs, where the current in-suit drinking device may be insufficient.

Identification of ideal resuscitation pressure with concurrent traumatic brain injury in a rat model of hemorrhagic shock.

PubMed

Hu, Yi; Wu, Yue; Tian, Kunlun; Lan, Dan; Chen, Xiangyun; Xue, Mingying; Liu, Liangming; Li, Tao

2015-05-01

Traumatic brain injury (TBI) is often associated with uncontrolled hemorrhagic shock (UHS), which contributes significantly to the mortality of severe trauma. Studies have demonstrated that permissive hypotension resuscitation improves the survival for uncontrolled hemorrhage. What the ideal target mean arterial pressure (MAP) is for TBI with UHS remains unclear. With the rat model of TBI in combination with UHS, we investigated the effects of a series of target resuscitation pressures (MAP from 50-90 mm Hg) on animal survival, brain perfusion, and organ function before hemorrhage controlled. Rats in 50-, 60-, and 70-mm Hg target MAP groups had less blood loss and less fluid requirement, a better vital organ including mitochondrial function and better cerebral blood flow, and animal survival (8, 6, and 7 of 10, respectively) than 80- and 90-mm Hg groups. The 70-mm Hg group had a better cerebral blood flow and cerebral mitochondrial function than in 50- and 60-mm Hg groups. In contrast, 80- and 90-mm Hg groups resulted in an excessive hemodilution, a decreased blood flow, an increased brain water content, and more severe cerebral edema. A 50-mm Hg target MAP is not suitable for the resuscitation of TBI combined with UHS. A 70 mm Hg of MAP is the ideal target resuscitation pressure for this trauma, which can keep sufficient perfusion to the brain and keep good organ function including cerebral mitochondrial function. Copyright © 2015 Elsevier Inc. All rights reserved.

Comparison of Measurements from Pressure-recording Inverted Echo Sounders and Satellite Altimetry in the North Equatorial Current Region of the Western Pacific

NASA Astrophysics Data System (ADS)

Jeon, Chanhyung; Park, Jae-Hun; Kim, Dong Guk; Kim, Eung; Jeon, Dongchull

2018-04-01

An array of 5 pressure-recording inverted echo sounders (PIESs) was deployed along the Jason-2 214 ground track in the North Equatorial Current (NEC) region of the western Pacific Ocean for about 2 years from June 2012. Round-trip acoustic travel time from the bottom to the sea surface and bottom pressure measurements from PIES were converted to sea level anomaly (SLA). AVISO along-track mono-mission SLA (Mono-SLA), reference mapped SLA (Ref-MSLA), and up-to-date mapped SLA (Upd-MSLA) products were used for comparison with PIESderived SLA (η tot). Comparisons of η tot with Mono-SLA revealed that hump artifact errors significantly contaminate the Mono-SLA. Differences of η tot from both Ref-MSLA and Upd-MSLA decreased as the hump errors were reduced in mapped SLA products. Comparisons of Mono-SLA measurements at crossover points of ground tracks near the observation sites revealed large differences though the time differences of their measurements were only 1.53 and 4.58 days. Comparisons between Mono-SLA and mapped SLA suggested that mapped SLA smooths out the hump artifact errors by taking values between the two discrepant Mono-SLA measurements at the crossover points. Consequently, mapped SLA showed better agreement with η tot at our observation sites. AVISO mapped sea surface height (SSH) products are the preferable dataset for studying SSH variability in the NEC region of the western Pacific, though some portions of hump artifact errors seem to still remain in them.

Prevalence of elevated mean arterial pressure and how fitness moderates its association with BMI in youth.

PubMed

Ogunleye, Ayodele A; Sandercock, Gavin R; Voss, Christine; Eisenmann, Joey C; Reed, Katharine

2013-11-01

Cardiorespiratory fitness is known to be cardioprotective and its association with the components of the metabolic syndrome in children is becoming clearer. The aim of the present study was to examine the extent to which cardiorespiratory fitness may offset the weight-related association with mean arterial pressure (MAP) in schoolchildren. Cross-sectional study. Schoolchildren from the East of England, U.K. A total of 5983 (48% females) schoolchildren, 10 to 16 years of age, had height, weight and blood pressure measured by standard procedures and cardiorespiratory fitness assessed by the 20 m shuttle-run test. Participants were classified as fit or unfit using internationally accepted fitness cut-off points; and as normal weight, overweight or obese based on BMI, again using international cut-off points. Age-adjusted ANCOVA was used to determine the main effects and interaction of fitness and BMI on MAP Z-score. Logistic regression models were used to estimate odds ratios of elevated MAP. Prevalence of elevated MAP in schoolchildren was 14.8% overall and 35.7% in those who were obese-unfit. Approximately 21% of participants were overweight and 5% obese, while 23% were classified as unfit. MAP generally increased across BMI categories and was higher in the aerobically unfit participants. Obese-fit males had lower MAP compared with obese-unfit males (P < 0.001); this trend was similar in females (P = 0.05). Increasing fitness level may have a positive impact on the weight-related elevations of MAP seen in obese and overweight schoolchildren.

High Versus Low Blood-Pressure Target in Experimental Ischemic Prolonged Cardiac Arrest Treated with Extra Corporeal Life Support.

PubMed

Fritz, Caroline; Kimmoun, Antoine; Vanhuyse, Fabrice; Trifan, Bogdan Florin; Orlowski, Sophie; Falanga, Aude; Marie, Vanessa; Groubatch, Frederique; Albuisson, Eliane; Tran, N'Guyen; Levy, Bruno

2017-06-01

There is currently no recommendation for the mean arterial pressure target in the particular setting of Extracorporeal Cardiopulmonary Resuscitation (ECPR) in the first hours following cardiogenic shock complicated by cardiac arrest. This study aimed to assess the effects of two different levels of mean arterial pressure on macrocirculatory, microcirculatory, and metabolic functions. Randomized animal study. University research laboratory. Ventricular fibrillation was induced in 14 male pigs by surgical ligature of the interventricular coronary artery. After 20 min of cardiopulmonary resuscitation, Extracorporeal Life Support (ECLS) was initiated to restore circulatory flow. Thereafter, animals were randomly allocated to a high mean arterial pressure group (High-MAP, 80-85 mm Hg) or to a standard mean arterial pressure group (Standard-MAP, 65-70 mm Hg). Assessments conducted at baseline, immediately following and 6 h after ECLS initiation were focused on lactate evolution, amount of infused fluid, and microcirculatory parameters. There was no significant difference between the two groups at the time of ECLS initiation and at 6 h with regard to lactate levels (High-MAP vs. Standard-MAP: 8.8 [6.7-12.9] vs. 9.6 [9.1-9.8] mmol·l, P = 0.779 and 8.9 [4.3-11.1] vs. 3.3 [2.4-11] mmol·l, P = 0.603). Infused fluid volume did not significantly differ between the two groups (4,000 [3,500-12,000] vs. 5,000 [2,500-18,000] mL, P = 0.977). There was also no significant difference between the two groups regarding renal and liver functions, and sublingual capillary microvascular flow index assessed by Sidestream Dark Field imaging. Compared with a standard mean arterial pressure regimen, targeting a high mean arterial pressure in the first hours of an experimental ECPR model did not result in any hemodynamic improvement nor in a decrease in the amount of infused fluid.

A wet/wet differential pressure sensor for measuring vertical hydraulic gradient.

PubMed

Fritz, Brad G; Mackley, Rob D

2010-01-01

Vertical hydraulic gradient is commonly measured in rivers, lakes, and streams for studies of groundwater-surface water interaction. While a number of methods with subtle differences have been applied, these methods can generally be separated into two categories; measuring surface water elevation and pressure in the subsurface separately or making direct measurements of the head difference with a manometer. Making separate head measurements allows for the use of electronic pressure sensors, providing large datasets that are particularly useful when the vertical hydraulic gradient fluctuates over time. On the other hand, using a manometer-based method provides an easier and more rapid measurement with a simpler computation to calculate the vertical hydraulic gradient. In this study, we evaluated a wet/wet differential pressure sensor for use in measuring vertical hydraulic gradient. This approach combines the advantage of high-temporal frequency measurements obtained with instrumented piezometers with the simplicity and reduced potential for human-induced error obtained with a manometer board method. Our results showed that the wet/wet differential pressure sensor provided results comparable to more traditional methods, making it an acceptable method for future use.

Glaucoma-related Changes in the Mechanical Properties and Collagen Micro-architecture of the Human Sclera

PubMed Central

Coudrillier, Baptiste; Pijanka, Jacek K.; Jefferys, Joan L.; Goel, Adhiraj; Quigley, Harry A.; Boote, Craig; Nguyen, Thao D.

2015-01-01

Objective The biomechanical behavior of the sclera determines the level of mechanical insult from intraocular pressure to the axons and tissues of the optic nerve head, as is of interest in glaucoma. In this study, we measure the collagen fiber structure and the strain response, and estimate the material properties of glaucomatous and normal human donor scleras. Methods Twenty-two posterior scleras from normal and diagnosed glaucoma donors were obtained from an eyebank. Optic nerve cross-sections were graded to determine the presence of axon loss. The specimens were subjected to pressure-controlled inflation testing. Full-field displacement maps were measured by digital image correlation (DIC) and spatially differentiated to compute surface strains. Maps of the collagen fiber structure across the posterior sclera of each inflated specimen were obtained using synchrotron wide-angle X-ray scattering (WAXS). Finite element (FE) models of the posterior scleras, incorporating a specimen-specific representation of the collagen structure, were constructed from the DIC-measured geometry. An inverse finite element analysis was developed to estimate the stiffness of the collagen fiber and inter-fiber matrix. Results The differences between glaucoma and non-glaucoma eyes were small in magnitude. Sectorial variations of degree of fiber alignment and peripapillary scleral strain significantly differed between normal and diagnosed glaucoma specimens. Meridional strains were on average larger in diagnosed glaucoma eyes compared with normal specimens. Non-glaucoma specimens had on average the lowest matrix and fiber stiffness, followed by undamaged glaucoma eyes, and damaged glaucoma eyes but the differences in stiffness were not significant. Conclusion The observed biomechanical and microstructural changes could be the result of tissue remodeling occuring in glaucoma and are likely to alter the mechanical environment of the optic nerve head and contribute to axonal damage. PMID:26161963

The effects of dietary fish oil on exercising skeletal muscle vascular and metabolic control in chronic heart failure rats.

PubMed

Holdsworth, Clark T; Copp, Steven W; Hirai, Daniel M; Ferguson, Scott K; Sims, Gabrielle E; Hageman, Karen S; Stebbins, Charles L; Poole, David C; Musch, Timothy I

2014-03-01

Impaired vasomotor control in chronic heart failure (CHF) is due partly to decrements in nitric oxide synthase (NOS) mediated vasodilation. Exercising muscle blood flow (BF) is augmented with polyunsaturated fatty acid (PUFA) supplementation via fish oil (FO) in healthy rats. We hypothesized that FO would augment exercising muscle BF in CHF rats via increased NO-bioavailability. Myocardial infarction (coronary artery ligation) induced CHF in Sprague-Dawley rats which were subsequently randomized to dietary FO (20% docosahexaenoic acid, 30% eicosapentaenoic acid, n = 15) or safflower oil (SO, 5%, n = 10) for 6-8 weeks. Mean arterial pressure (MAP), blood [lactate], and hindlimb muscles BF (radiolabeled microspheres) were determined at rest, during treadmill exercise (20 m·min(-1), 5% incline) and exercise + N(G)-nitro-l-arginine-methyl-ester (l-NAME) (a nonspecific NOS inhibitor). FO did not change left ventricular end-diastolic pressure (SO: 14 ± 2; FO: 11 ± 1 mm Hg, p > 0.05). During exercise, MAP (SO: 128 ± 3; FO: 132 ± 3 mm Hg) and blood [lactate] (SO: 3.8 ± 0.4; FO: 4.6 ± 0.5 mmol·L(-1)) were not different (p > 0.05). Exercising hindlimb muscle BF was lower in FO than SO (SO: 120 ± 11; FO: 93 ± 4 mL·min(-1)·100 g(-1), p < 0.05) but was not differentially affected by l-NAME. Specifically, 17 of 28 individual muscle BF's were lower (p < 0.05) in FO demonstrating that PUFA supplementation with FO in CHF rats does not augment muscle BF during exercise but may lower metabolic cost.

High-resolution mapping of yield curve shape and evolution for high porosity sandstones

NASA Astrophysics Data System (ADS)

Bedford, J. D.; Faulkner, D.; Wheeler, J.; Leclere, H.

2017-12-01

The onset of permanent inelastic deformation for porous rock is typically defined by a yield curve plotted in P-Q space, where P is the effective mean stress and Q is the differential stress. Sandstones usually have broadly elliptical shaped yield curves, with the low pressure side of the ellipse associated with localized brittle faulting (dilation) and the high pressure side with distributed ductile deformation (compaction). However recent works have shown that these curves might not be perfectly elliptical and that significant evolution in shape occurs with continued deformation. We therefore use a novel stress-probing methodology to map in high-resolution the yield curve shape for Boise and Idaho Gray sandstones (36-38% porosity) and also investigate curve evolution with increasing deformation. The data reveal yield curves with a much flatter geometry than previously recorded for porous sandstone and that the compactive side of the curve is partly comprised of a near vertical limb. The yield curve evolution is found to be strongly dependent on the nature of inelastic strain. Samples that were compacted under a deviatoric load, with a component of inelastic shear strain, were found to have yield curves with peaks that are approximately 50% higher than similar porosity samples that were hydrostatically compacted (i.e. purely volumetric strain). The difference in yield curve evolution along the different loading paths is attributed to mechanical anisotropy that develops during deviatoric loading by the closure of preferentially orientated fractures. Increased shear strain also leads to the formation of a plateau at the peak of the yield curve as samples deform along the deviatoric loading path. These results have important implications for understanding how the strength of porous rock evolves along different stress paths, including during fluid extraction from hydrocarbon reservoirs where the stress state is rarely isotropic.

Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

PubMed

Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

2016-09-01

Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

Mean Arterial Blood Pressure Correlates with Neurological Recovery after Human Spinal Cord Injury: Analysis of High Frequency Physiologic Data

PubMed Central

Hawryluk, Gregory; Whetstone, William; Saigal, Rajiv; Ferguson, Adam; Talbott, Jason; Bresnahan, Jacqueline; Dhall, Sanjay; Pan, Jonathan; Beattie, Michael

2015-01-01

Abstract Current guidelines for the care of patients with acute spinal cord injuries (SCIs) recommend maintaining mean arterial pressure (MAP) values of 85–90 mm Hg for 7 days after an acute SCI however, little evidence supports this recommendation. We sought to better inform the relationship between MAP values and neurological recovery. A computer system automatically collected and stored q1 min physiological data from intensive care unit monitors on patients with SCI over a 6-year period. Data for 100 patients with acute SCI were collected. 74 of these patients had American Spinal Injury Association Impairment Scale (AIS) grades determined by physical examination on admission and at time of hospital discharge. Average MAP values as well as the proportion of MAP values below thresholds were explored for values from 120 mm Hg to 40 mm Hg in 1 mm Hg increments; the relationship between these measures and outcome was explored at various time points up to 30 days from the time of injury. A total of 994,875 q1 min arterial line blood pressure measurements were recorded for the included patients amid 1,688,194 min of recorded intensive care observations. A large proportion of measures were below 85 mm Hg despite generally acceptable average MAP values. Higher average MAP values correlated with improved recovery in the first 2–3 days after SCI while the proportion of MAP values below the accepted threshold of 85 mm Hg seemed a stronger correlate, decreasing in strength over the first 5–7 days after injury. This study provides strong evidence supporting a correlation between MAP values and neurological recovery. It does not, however, provide evidence of a causal relationship. Duration of hypotension may be more important than average MAP. It provides support for the notion of MAP thresholds in SCI recovery, and the highest MAP values correlated with the greatest degree of neurological recovery. The results are concordant with current guidelines in suggesting that MAP thresholds >85 mm Hg may be appropriate after acute SCI. PMID:25669633

The Structure-Mapping Engine.

DTIC Science & Technology

1986-05-01

according to the following mapping rules: (1) Attributes of objects are dropped: e.g. RED ( b1 ) -I> RED (t ~) -4 .(2) Relations between objects in the...beaker,viai,water, pipe) B1 T2 T3 TEMPERATURE(coffee) TEMPERATURE(ice cube) ’ . B2 B3 PRESSURE(beaker) PRESSURE(vial) GREATER B4 FLOW(ice cube,coffee,heat...Wasnington, DC 20057 ERIC Facility-Acquisitions Dr Kenneth D. Forbus .5 V 4833 Rugby Avenue University of Illinois Dr. Robert Glaser Bethesda, MD 20014

Role of central command in carotid baroreflex resetting in humans during static exercise

NASA Technical Reports Server (NTRS)

Ogoh, S.; Wasmund, W. L.; Keller, D. M.; O-Yurvati, A.; Gallagher, K. M.; Mitchell, J. H.; Raven, P. B.

2002-01-01

The purpose of the experiments was to examine the role of central command in the exercise-induced resetting of the carotid baroreflex. Eight subjects performed 30 % maximal voluntary contraction (MVC) static knee extension and flexion with manipulation of central command (CC) by patellar tendon vibration (PTV). The same subjects also performed static knee extension and flexion exercise without PTV at a force development that elicited the same ratings of perceived exertion (RPE) as those observed during exercise with PTV in order to assess involvement of the exercise pressor reflex. Carotid baroreflex (CBR) function curves were modelled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid changes in neck pressure and suction during steady state static exercise. Knee extension exercise with PTV (decreased CC activation) reset the CBR-HR and CBR-MAP to a lower operating pressure (P < 0.05) and knee flexion exercise with PTV (increased CC activation) reset the CBR-HR and CBR-MAP to a higher operating pressure (P < 0.05). Comparison between knee extension and flexion exercise at the same RPE with and without PTV found no difference in the resetting of the CBR-HR function curves (P > 0.05) suggesting the response was determined primarily by CC activation. However, the CBR-MAP function curves were reset to operating pressures determined by both exercise pressor reflex (EPR) and central command activation. Thus the physiological response to exercise requires CC activation to reset the carotid-cardiac reflex but requires either CC or EPR to reset the carotid-vasomotor reflex.

Pooled analysis of higher versus lower blood pressure targets for vasopressor therapy septic and vasodilatory shock.

PubMed

Lamontagne, François; Day, Andrew G; Meade, Maureen O; Cook, Deborah J; Guyatt, Gordon H; Hylands, Mathieu; Radermacher, Peter; Chrétien, Jean-Marie; Beaudoin, Nicolas; Hébert, Paul; D'Aragon, Frédérick; Meziani, Ferhat; Asfar, Pierre

2018-01-01

Guidelines for shock recommend mean arterial pressure (MAP) targets for vasopressor therapy of at least 65 mmHg and, until recently, suggested that patients with underlying chronic hypertension and atherosclerosis may benefit from higher targets. We conducted an individual patient-data meta-analysis of recent trials to determine if patient variables modify the effect of different MAP targets. We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials for randomized controlled trials of higher versus lower blood pressure targets for vasopressor therapy in adult patients in shock (until November 2017). After obtaining individual patient data from both eligible trials, we used a modified version of the Cochrane Collaboration's instrument to assess the risk of bias of included trials. The primary outcome was 28-day mortality. Included trials enrolled 894 patients. Controlling for trial and site, the OR for 28-day mortality for the higher versus lower MAP targets was 1.15 (95% CI 0.87-1.52). Treatment effect varied by duration of vasopressors before randomization (interaction p = 0.017), but not by chronic hypertension, congestive heart failure or age. Risk of death increased in higher MAP groups among patients on vasopressors > 6 h before randomization (OR 3.00, 95% CI 1.33-6.74). Targeting higher blood pressure targets may increase mortality in patients who have been treated with vasopressors for more than 6 h. Lower blood pressure targets were not associated with patient-important adverse events in any subgroup, including chronically hypertensive patients.

Geometrical Model of Solar Radiation Pressure Based on High-Performing Galileo Clocks - First Geometrical Mapping of the Yarkowsky effect

NASA Astrophysics Data System (ADS)

Svehla, Drazen; Rothacher, Markus; Hugentobler, Urs; Steigenberger, Peter; Ziebart, Marek

2014-05-01

Solar radiation pressure is the main source of errors in the precise orbit determination of GNSS satellites. All deficiencies in the modeling of Solar radiation pressure map into estimated terrestrial reference frame parameters as well as into derived gravity field coefficients and altimetry results when LEO orbits are determined using GPS. Here we introduce a new approach to geometrically map radial orbit perturbations of GNSS satellites using highly-performing clocks on board the first Galileo satellites. Only a linear model (time bias and time drift) needs to be removed from the estimated clock parameters and the remaining clock residuals map all radial orbit perturbations along the orbit. With the independent SLR measurements, we show that a Galileo clock is stable enough to map radial orbit perturbations continuously along the orbit with a negative sign in comparison to SLR residuals. Agreement between the SLR residuals and the clock residuals is at the 1 cm RMS for an orbit arc of 24 h. Looking at the clock parameters determined along one orbit revolution over a period of one year, we show that the so-called SLR bias in Galileo and GPS orbits can be explained by the translation of the determined orbit in the orbital plane towards the Sun. This orbit translation is due to thermal re-radiation and not accounting for the Sun elevation in the parameterization of the estimated Solar radiation pressure parameters. SLR ranging to GNSS satellites takes place typically at night, e.g. between 6 pm and 6 am local time when the Sun is in opposition to the satellite. Therefore, SLR observes only one part of the GNSS orbit with a negative radial orbit error that is mapped as an artificial bias in SLR observables. The Galileo clocks clearly show orbit translation for all Sun elevations: the radial orbit error is positive when the Sun is in conjuction (orbit noon) and negative when the Sun is in opposition (orbit midnight). The magnitude of this artificial negative SLR bias depends on the orbit quality and should rather be called GNSS orbit bias instead of SLR bias. When LEO satellite orbits are estimated using GPS, this GPS orbit bias is mapped into the antenna phase center. All LEO satellites, such as CHAMP, GRACE and JASON-1/2, need an adjustment of the radial antenna phase center offset. GNSS orbit translations towards the Sun in the orbital plane do not only propagate into the estimated LEO orbits, but also into derived gravity field and altimetry products. Geometrical mapping of orbit perturbations using an on board GNSS clock is a new technique to monitor orbit perturbations along the orbit and was successfully applied in the modeling of Solar radiation pressure. We show that CODE Solar radiation pressure parameterization lacks dependency with the Sun's elevation, i.e. elongation angle (rotation of Solar arrays), especially at low Sun elevations (eclipses). Parameterisation with the Sun elongation angle is used in the so-called T30 model (ROCK-model) that includes thermal re-radiation. A preliminary version of Solar radiation pressure for the first five Galileo and the GPS-36 satellite is based on 2×180 days of the MGEX Campaign. We show that Galileo clocks map the Yarkowsky effect along the orbit, i.e. the lag between the Sun's illumination and thermal re-radiation. We present the first geometrical mapping of anisotropic thermal emission of absorbed sunlight of an illuminated satellite. In this way, the effects of Solar radiation pressure can be modelled with only two paramaters for all Sun elevations.

Mechanical characterization and durability of sintered porous transport layers for polymer electrolyte membrane electrolysis

NASA Astrophysics Data System (ADS)

Borgardt, Elena; Panchenko, Olha; Hackemüller, Franz Josef; Giffin, Jürgen; Bram, Martin; Müller, Martin; Lehnert, Werner; Stolten, Detlef

2018-01-01

Differential pressure electrolysis offers the potential for more efficient hydrogen compression. Due to the differential pressures acting within the electrolytic cell, the porous transport layer (PTL) is subjected to high stress. For safety reasons, the PTL's mechanical stability must be ensured. However, the requirements for high porosity and low thickness stand in contrast to that for mechanical stability. Porous transport layers for polymer electrolyte membrane (PEM) electrolysis are typically prepared by means of the thermal sintering of titanium powder. Thus far, the factors that influence the mechanical strength of the sintered bodies and how all requirements can be simultaneously fulfilled have not been investigated. Here, the static and dynamic mechanical properties of thin sintered titanium sheets are investigated ex-situ via tensile tests and periodic loading in a test cell, respectively. In order for a sintered PTL with a thickness of 500 μm and porosities above 25% to be able to withstand 50 bar differential pressure in the cell, the maximum flow field width should be limited to 3 mm. Thus, a method was developed to test the suitability of PTL materials for use in electrolysis for various differential pressures and flow field widths.

Concomitant administration of nitrous oxide and remifentanil reduces oral tissue blood flow without decreasing blood pressure during sevoflurane anesthesia in rabbits.

PubMed

Kasahara, Masataka; Ichinohe, Tatsuya; Okamoto, Sota; Okada, Reina; Kanbe, Hiroaki; Matsuura, Nobuyuki

2015-06-01

To determine whether continuous administration of nitrous oxide and remifentanil—either alone or together—alters blood flow in oral tissues during sevoflurane anesthesia. Eight male tracheotomized Japanese white rabbits were anesthetized with sevoflurane under mechanical ventilation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), common carotid arterial blood flow (CCBF), tongue mucosal blood flow (TMBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF) were recorded in the absence of all test agents and after administration of the test agents (50 % nitrous oxide, 0.4 μg/kg/min remifentanil, and their combination) for 20 min. Nitrous oxide increased SBP, DBP, MAP, CCBF, BBF, MBF, UBF, and LBF relative to baseline values but did not affect HR or TMBF. Remifentanil decreased all hemodynamic variables except DBP. Combined administration of nitrous oxide and remifentanil recovered SBP, DBP, MAP, and CCBF to baseline levels, but HR and oral tissue blood flow remained lower than control values. Our findings suggest that concomitant administration of nitrous oxide and remifentanil reduces blood flow in oral tissues without decreasing blood pressure during sevoflurane anesthesia in rabbits.

Factors affecting the healing of pressure ulcers in a Korean acute care hospital.

PubMed

Sung, Young Hee; Park, Kyung Hee

2011-01-01

We sought to determine the factors affecting pressure ulcer (PU) healing in an acute care facility in Korea. Data were collected between October 1, 2006, and September 30, 2007, regarding PU status and factors hypothesized to influence wound healing. We developed a form that queried factors thought to affect PU healing based on literature review. We also administered the Pressure Ulcer Scale for Healing (PUSH) tool to assess healing of PUs and calculated change in PUSH scale as the outcome variable reflecting the magnitude of the healing of PU. One hundred fifty eight patients with a total of 326 PUs in an acute care hospital located in Seoul, Korea, comprised the sample. The variables found to significantly affect PU healing included mean arterial pressure (MAP), serum albumin level, urinary incontinence, consultation with nutritionist, Braden Scale scale, wound size, and exudate amount. Pressure ulcer healing was improved when the MAP was higher (B = 0.034) and the serum albumin level was more than 2.8 g/dL (20.8 grams/liter) (B = 1.107). When managing patients in an acute care setting, PU healing may be improved by maintaining MAP and providing protein supplements to keep serum albumin level greater than 2.8 g/dL (20.8 grams/liter).

Map of forest ownership in the conterminous United States. [Scale 1:7,500,000].

Treesearch

Mark D. Nelson; Greg C. Liknes; Brett J. Butler

2010-01-01

This map depicts the spatial distribution of forest land across the conterminous United States, in 2007, differentiated into public vs. private forest land, and the percentage of corporate ownership of private forest land. Notable differences between eastern and western United States are evident on the map. Over two-thirds of western forest land is publicly owned, the...

Application of multispectral remote sensing to soil survey research in Indiana

NASA Technical Reports Server (NTRS)

Zachary, A. L.; Cipra, J. E.; Diderickson, R. I.; Kristof, S. J.; Baumgardner, M. F.

1972-01-01

Computer-implemented mappings based on spectral properties of bare soil surfaces were compared with mapping units of interest to soil surveyors. Some soil types could be differentiated by their spectral properties. In other cases, soils with similar surface colors and textures could not be distinguished spectrally. The spectral maps seemed useful for delineating boundaries between soils in many cases.

Polynomial approximation of Poincare maps for Hamiltonian system

NASA Technical Reports Server (NTRS)

Froeschle, Claude; Petit, Jean-Marc

1992-01-01

Different methods are proposed and tested for transforming a non-linear differential system, and more particularly a Hamiltonian one, into a map without integrating the whole orbit as in the well-known Poincare return map technique. We construct piecewise polynomial maps by coarse-graining the phase-space surface of section into parallelograms and using either only values of the Poincare maps at the vertices or also the gradient information at the nearest neighbors to define a polynomial approximation within each cell. The numerical experiments are in good agreement with both the real symplectic and Poincare maps.

Quasipolynomial generalization of Lotka-Volterra mappings

NASA Astrophysics Data System (ADS)

Hernández-Bermejo, Benito; Brenig, Léon

2002-07-01

In recent years, it has been shown that Lotka-Volterra mappings constitute a valuable tool from both the theoretical and the applied points of view, with developments in very diverse fields such as physics, population dynamics, chemistry and economy. The purpose of this work is to demonstrate that many of the most important ideas and algebraic methods that constitute the basis of the quasipolynomial formalism (originally conceived for the analysis of ordinary differential equations) can be extended into the mapping domain. The extension of the formalism into the discrete-time context is remarkable as far as the quasipolynomial methodology had never been shown to be applicable beyond the differential case. It will be demonstrated that Lotka-Volterra mappings play a central role in the quasipolynomial formalism for the discrete-time case. Moreover, the extension of the formalism into the discrete-time domain allows a significant generalization of Lotka-Volterra mappings as well as a whole transfer of algebraic methods into the discrete-time context. The result is a novel and more general conceptual framework for the understanding of Lotka-Volterra mappings as well as a new range of possibilities that become open not only for the theoretical analysis of Lotka-Volterra mappings and their generalizations, but also for the development of new applications.

Development of a 5,000 m(3) super-pressure balloon with a diamond-shaped net

NASA Astrophysics Data System (ADS)

Saito, Yoshitaka; Tanaka, Shigeki; Nakashino, Kyoichi; Matsushima, Kiyoho; Goto, Ken; Furuta, Ryosuke; Domoto, Kodai; Akita, Daisuke; Hashimoto, Hiroyuki

A light super-pressure balloon of which weight will be comparable to the weight of the zero-pressure balloon has been developed using a method to cover a balloon with a diamond-shaped net of high-tensile fibers. The goal is to fly a payload of 900 kg to the altitude of 37 km with a 300,000 m(3) balloon. A flight test of a 3,000 m(3) balloon in the tandem balloon configuration with a 15,000 m(3) zero-pressure balloon was performed in 2012. Although a small gas leak occurred in the super-pressure balloon at the differential pressure of 400 to 500 Pa, the differential pressure reached the highest value of 814 Pa and kept positive through the level flight lasting for 25 minutes due to its slow leakage. To avoid a possible stress concentration to films at the polar area, a new design setting the meridian length of the balloon gore film equal to the length of the net was adopted. A 3-m balloon with the design was developed and its capacity to resist pressure at room temperature and at -30 (°) C was checked through the ground inflation tests. In 2013, a balloon of the same model was launched in the tandem balloon configuration with 2 kg rubber balloons. It was confirmed that the balloon could withstand the maximum differential pressure of 6,280 Pa, could withstand the differential pressure of 5,600 Pa for 2 hours, and there was a small gas leak through a hole with an area of 0.4 mm(2) which was also found in the ground leakage test. These results indicated that the improvement was adequate and there was no problem for the super-pressure balloon to fly in the environment of the stratosphere except for the problem of the small gas leak. In 2014, a flight test of a 5,000 m(3) balloon will be performed. In this paper, after reviewing the method to cover a balloon with a diamond-shaped net, the current status of the development will be reported.

Acute Radiation Hypotension in the Rabbit: a Model for the Human Radiation Shock Syndrome.

NASA Astrophysics Data System (ADS)

Makale, Milan Theodore

This study has shown that total body irradiation (TBI) of immature (40 to 100 day old) rabbits leads to an acute fall in mean arterial pressure (MAP) 30 to 90 minutes after exposure, which takes no more than about three minutes, and often results in pressures which are less than 50% of the lowest pre-exposure MAP. This is termed acute cardiovascular collapse (ACC). ACC is often accompanied by ECG T-wave elevation, a sharp rise in ear temperature, labored breathing, pupillary constriction, bladder emptying, and loss of abdominal muscle tone. About 73% of 40 to 100 day rabbits exhibit ACC; the others and most older rabbits display gradual pressure reductions (deliberate hypotension) which may be profound, and which may be accompanied by the same changes associated with ACC. ACC and deliberate hypotension occurred in rabbits cannulated in the dorsal aorta, and in non-operated animals. The decline in MAP for all 40 to 100 day cannulated rabbits (deliberate and ACC responders) is 55.4%. The experiments described below only involved 40 to 100 day cannulated TBI rabbits. Heart region irradiation resulted in an average MAP decline of 29.1%, with 1/15 rabbits showing ACC. Heart shielding during TBI reduced the decline in MAP to 19%, with 1/10 rabbits experiencing ACC. These results imply that the heart region, which includes the heart, part of the lungs, neural receptors, roots of the systemic vessels, and the blood, is a sensitive target. Bilateral vagotomy reduced the decline in MAP to 24.9%, and abolished ACC. Atropine (6 mg/kg) reduced the frequency of ACC to 26%, and the decline in MAP to 41.4%. In 11/13 rabbits the voltage generated by left vagal transmission rose after TBI. The vagi appear to participate in radiation hypotension. Heart shielding together with bilateral vagotomy reduced the decline in MAP to only 9.9%, with no ACC responders. The mean right ventricular pressure (MRVP) rose after TBI in 8/10 rabbits. In animals which displayed either ACC or steep deliberate hypotension, the MRVP rose sharply prior to the rapid decline in MAP. This suggests that the pulmonary blood flow was impeded, possibly causing right heart failure (cor pulmonale), and consequent cardiovascular collapse.

Method and system for measuring multiphase flow using multiple pressure differentials

DOEpatents

Fincke, James R.

2001-01-01

An improved method and system for measuring a multiphase flow in a pressure flow meter. An extended throat venturi is used and pressure of the multiphase flow is measured at three or more positions in the venturi, which define two or more pressure differentials in the flow conduit. The differential pressures are then used to calculate the mass flow of the gas phase, the total mass flow, and the liquid phase. The method for determining the mass flow of the high void fraction fluid flow and the gas flow includes certain steps. The first step is calculating a gas density for the gas flow. The next two steps are finding a normalized gas mass flow rate through the venturi and computing a gas mass flow rate. The following step is estimating the gas velocity in the venturi tube throat. The next step is calculating the pressure drop experienced by the gas-phase due to work performed by the gas phase in accelerating the liquid phase between the upstream pressure measuring point and the pressure measuring point in the venturi throat. Another step is estimating the liquid velocity in the venturi throat using the calculated pressure drop experienced by the gas-phase due to work performed by the gas phase. Then the friction is computed between the liquid phase and a wall in the venturi tube. Finally, the total mass flow rate based on measured pressure in the venturi throat is calculated, and the mass flow rate of the liquid phase is calculated from the difference of the total mass flow rate and the gas mass flow rate.

[Differentiation between moisture lesions and pressure ulcers using photographs in a critical area].

PubMed

Valls-Matarín, Josefa; Del Cotillo-Fuente, Mercedes; Pujol-Vila, María; Ribal-Prior, Rosa; Sandalinas-Mulero, Inmaculada

2016-01-01

To identify difficulties for nurses in differentiating between moisture lesions and pressure ulcers, proper classification of pressure ulcers to assess the adequate classification of the Grupo Nacional para el Estudio y Asesoramiento de Úlceras por Presión y Heridas Crónicas (GNEAUPP) and the degree of agreement in the correct assessment by type and category of injury. Cross-sectional study in a critical area during 2014. All nurses who agreed to participate were included. They performed a questionnaire with 14 photographs validated by experts of moisture lesions or pressure ulcers in the sacral area and buttocks, with 6 possible answers: Pressure ulcer category I, II, III, IV, moisture lesions and unknown. Demographics and knowledge of the classification system of the pressure ulcers were collected according to GNEAUPP. It involved 98% of the population (n=56); 98.2% knew the classification system of the GNEAUPP; 35.2% of moisture lesions were considered as pressure ulcers, most of them as a category II (18.9%). The 14.8% of the pressure ulcers photographs were identified as moisture lesions and 16.1% were classified in another category. The agreement between nurses earned a global Kappa index of .38 (95% CI: .29-.57). There are difficulties differentiating between pressure ulcers and moisture lesions, especially within initial categories. Nurses have the perception they know the pressure ulcers classification, but they do not classify them correctly. The degree of concordance in the diagnosis of skin lesions was low. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

Check valve installation in pilot operated relief valve prevents reverse pressurization

NASA Technical Reports Server (NTRS)

Oswalt, L.

1966-01-01

Two check valves prevent reverse flow through pilot-operated relief valves of differential area piston design. Title valves control pressure flow to ensure that the piston dome pressure is always at least as great as the main relief valve discharge pressure.

Evoked Pressure Pain Sensitivity Is Associated with Differential Analgesic Response to Verum and Sham Acupuncture in Fibromyalgia.

PubMed

Zucker, Noah A; Tsodikov, Alex; Mist, Scott D; Cina, Stephen; Napadow, Vitaly; Harris, Richard E

2017-08-01

Fibromyalgia is a chronic pain condition with few effective treatments. Many fibromyalgia patients seek acupuncture for analgesia; however, its efficacy is limited and not fully understood. This may be due to heterogeneous pathologies among participants in acupuncture clinical trials. We hypothesized that pressure pain tenderness would differentially classify treatment response to verum and sham acupuncture in fibromyalgia patients. Baseline pressure pain sensitivity at the thumbnail at baseline was used in linear mixed models as a modifier of differential treatment response to sham versus verum acupuncture. Similarly, needle-induced sensation was also analyzed to determine its differential effect of treatment on clinical pain. A cohort of 114 fibromyalgia patients received baseline pressure pain testing and were randomized to either verum (N = 59) or sham (N = 55) acupuncture. Participants received treatments from once a week to three times a week, increasing in three-week blocks for a total of 18 treatments. Clinical pain was measured on a 101-point visual analog scale, and needle sensation was measured by questionnaire throughout the trial. Participants who had higher pain pressure thresholds had greater reduction in clinical pain following verum acupuncture while participants who had lower pain pressure thresholds showed better analgesic response to sham acupuncture. Moreover, patients with lower pressure pain thresholds had exacerbated clinical pain following verum acupuncture. Similar relationships were observed for sensitivity to acupuncture needling. These findings suggest that acupuncture efficacy in fibromyalgia may be underestimated and a more personalized treatment for fibromyalgia may also be possible. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

High-pressure differential thermal analysis/dilatometric apparatus based on an Instron capillary rheometer

NASA Astrophysics Data System (ADS)

Hsiao, B. S.; Shaw, M. T.; Samulski, E. T.

1987-06-01

A high-pressure apparatus in the form of a modified Instron capillary rheometer capable of measuring differential thermal analysis (DTA) data and pressure-volume-temperature (P-V-T) relations was constructed in our laboratory. Temperatures from 20 to 370 °C and pressures from 1 to 6000 bar are achievable with a data-acquisition and control system based on an APPLE II+ microcomputer. Measurements of pressure to an accuracy of 1%, temperature of 0.5%, and volume change of 0.1% have been obtained. Software was developed to operate the experiments at fixed heating or cooling rates as well as at a constant pressure or with isothermal pressure sweeps. Polymer samples were compressed into rods preceding the experiment by a vacuum molder to eliminate voids. Low-density polyethylene (LDPE) was run as an example to demonstrate the performance of this pressure apparatus. The results revealed an excellent match between our experimental data and the published data.

Mapping soil total nitrogen of cultivated land at county scale by using hyperspectral image

NASA Astrophysics Data System (ADS)

Gu, Xiaohe; Zhang, Li Yan; Shu, Meiyan; Yang, Guijun

2018-02-01

Monitoring total nitrogen content (TNC) in the soil of cultivated land quantitively and mastering its spatial distribution are helpful for crop growing, soil fertility adjustment and sustainable development of agriculture. The study aimed to develop a universal method to map total nitrogen content in soil of cultivated land by HSI image at county scale. Several mathematical transformations were used to improve the expression ability of HSI image. The correlations between soil TNC and the reflectivity and its mathematical transformations were analyzed. Then the susceptible bands and its transformations were screened to develop the optimizing model of map soil TNC in the Anping County based on the method of multiple linear regression. Results showed that the bands of 14th, 16th, 19th, 37th and 60th with different mathematical transformations were screened as susceptible bands. Differential transformation was helpful for reducing the noise interference to the diagnosis ability of the target spectrum. The determination coefficient of the first order differential of logarithmic transformation was biggest (0.505), while the RMSE was lowest. The study confirmed the first order differential of logarithm transformation as the optimal inversion model for soil TNC, which was used to map soil TNC of cultivated land in the study area.

Renal sympathetic nerve activity measured by norepinephrine spillover rate in response to changes in blood pressure in conscious rabbits.

PubMed

Sano, N; Way, D; McGrath, B P

1989-04-01

1. Renal sympathetic nerve activity (RSNA) in response to changes in mean arterial pressure (MAP) was examined by measuring renal norepinephrine (NE) spillover rate in conscious rabbits. 2. A chronic renal vein catheter was implanted for sampling renal venous blood without stress in conscious animals. 3. RSNA estimated by renal NE spillover rate significantly increased in response to moderate falls in MAP produced by sodium nitroprusside (SNP) infusion and decreased in response to moderate rises in MAP produced by phenylephrine (PE) infusion. 4. The NE spillover method is sufficiently sensitive to detect responses of RSNA to physiological stimuli in conscious rabbits.

Extracellular Volume Fraction for Characterization of Patients With Heart Failure and Preserved Ejection Fraction.

PubMed

Rommel, Karl-Philipp; von Roeder, Maximilian; Latuscynski, Konrad; Oberueck, Christian; Blazek, Stephan; Fengler, Karl; Besler, Christian; Sandri, Marcus; Lücke, Christian; Gutberlet, Matthias; Linke, Axel; Schuler, Gerhard; Lurz, Philipp

2016-04-19

Optimal patient characterization in heart failure with preserved ejection fraction (HFpEF) is essential to tailor successful treatment strategies. Cardiac magnetic resonance (CMR)-derived T1 mapping can noninvasively quantify diffuse myocardial fibrosis as extracellular volume fraction (ECV). This study aimed to elucidate the diagnostic performance of T1 mapping in HFpEF by examining the relationship between ECV and invasively measured parameters of diastolic function. It also investigated the potential of ECV to differentiate among pathomechanisms in HFpEF. We performed T1 mapping in 24 patients with HFpEF and 12 patients without heart failure symptoms. Pressure-volume loops were obtained with a conductance catheter during basal conditions and handgrip exercise. Transient pre-load reduction was used to extrapolate the diastolic stiffness constant. Patients with HFpEF showed higher ECV (p < 0.01), elevated load-independent passive left ventricular (LV) stiffness constant (beta) (p < 0.001), and a longer time constant of active LV relaxation (p = 0.02). ECV correlated highly with beta (r = 0.75; p < 0.001). Within the HFpEF cohort, patients with ECV greater than the median showed a higher beta (p = 0.05), whereas ECV below the median identified patients with prolonged active LV relaxation (p = 0.01) and a marked hypertensive reaction to exercise due to pathologic arterial elastance (p = 0.04). On multiple linear regression analyses, ECV independently predicted intrinsic LV stiffness (β = 0.75; p < 0.01). Diffuse myocardial fibrosis, assessed by CMR-derived T1 mapping, independently predicts invasively measured LV stiffness in HFpEF. Additionally, ECV helps to noninvasively distinguish the role of passive stiffness and hypertensive exercise response with impaired active relaxation. (Left Ventricular Stiffness vs. Fibrosis Quantification by T1 Mapping in Heart Failure With Preserved Ejection Fraction [STIFFMAP]; NCT02459626). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Challenges in Unmanned Aerial Vehicle Photogrammetry for Archaeological Mapping at High Elevations

NASA Astrophysics Data System (ADS)

Adams, J. A.; Wernke, S.

2015-12-01

Unmanned Aerial Vehicles (UAVs), especially multi-rotor vehicles, are becoming ubiquitous and their appeal for generating photogrammetry-based maps has grown. The options are many and costs have plummeted in last five years; however, many challenges persist with their deployment. We mapped the archaeological site Maw­chu Llacta, a settlement in the southern highlands of Peru (Figure 1). Mawchu Llacta is a planned colonial town built over a major Inka-era center in the high-elevation grasslands at ~4,000m asl. The "general resettlement of Indians" was a massive forced resettlement program, for which very little local-level documentation exists. Mawachu Llacta's excellently preserved architecture includes >500 buildings and hundreds of walls spread across ~13h posed significant mapping challenges. Many environmental factors impact UAV deployment. The air pressure at 4,100 m asl is dramatically lower than at sea level. The dry season diurnal temperature differentials can vary from 7°C to 22°C daily. High and hot conditions frequently occur from late morning to early afternoon. Reaching Mawchu Llacta requires hiking 4km with 400m of vertical gain over steep and rocky terrain. There is also no on-site power or secure storage. Thus, the UAV must be packable. FAA regulations govern US UAV deployments, but regulations were less stringent in Peru. However, ITAR exemptions and Peruvian customs requirements were required. The Peruvian government has established an importation and approval process that entails leaving the UAV at customs, while obtaining the necessary government approvals, both of which can be problematic. We have deployed the Aurora Flight Sciences Skate fixed wing ßUAV, an in-house fixed wing UAV based on the Skywalker X-5 flying wing, and a tethered 9 m3 capacity latex meteorological weather balloon. Development of an autonomous blimp/balloon has been ruled-out. A 3DR Solo is being assessed for excavation mapping.

Method of fabricating an article with cavities. [with thin bottom walls

NASA Technical Reports Server (NTRS)

Dale, W. J.; Jurscaga, G. M. (Inventor)

1974-01-01

An article having a cavity with a thin bottom wall is provided by assembling a thin sheet, for example, a metal sheet, adjacent to the surface of a member having one or more apertures. A bonding adhesive is interposed between the thin sheet and the subadjacent member, and the thin sheet is subjected to a high fluid pressure. In order to prevent the differential pressure from being exerted against the thin sheet, the aperture is filled with a plug of solid material having a linear coefficient of thermal expansion higher than that of the member. When the assembly is subjected to pressure, the material is heated to a temperature such that its expansion exerts a pressure against the thin sheet thus reducing the differential pressure.

Exposure of young dairy cattle to Mycobacterium avium subsp. paratuberculosis (MAP) through intensive grazing of contaminated pastures in a herd positive for Johne's disease.

PubMed

Fecteau, Marie-Eve; Whitlock, Robert H; Buergelt, Claus D; Sweeney, Raymond W

2010-02-01

This study investigated the susceptibility of 1- to 2-year-old cattle to Mycobacterium avium subsp. paratuberculosis (MAP) on pasture previously grazed by infected cattle. The exposure of yearling cattle to pastures contaminated with MAP resulted in infection with MAP, showing that age resistance to infection can be overcome by pressure of infection.

Mitochondrial complex I and NAD(P)H oxidase are major sources of exacerbated oxidative stress in pressure-overloaded ischemic-reperfused hearts.

PubMed

Mozaffari, Mahmood S; Baban, Babak; Liu, Jun Yao; Abebe, Worku; Sullivan, Jennifer C; El-Marakby, Ahmed

2011-03-01

We tested the hypothesis that pressure overload exacerbates oxidative stress associated with augmented mitochondrial permeability transition (MPT) pore opening and cell death in ischemic-reperfused hearts. Pressure overload decreased the level of reduced glutathione but increased nitrotyrosine and 8-hydroxydeoxyguanosine levels in ischemic-reperfused hearts. The activity of catalase, but not superoxide dismutase (SOD), was lower in ischemic-reperfused hearts perfused at higher pressure. Mitochondria from ischemic-reperfused hearts subjected to higher perfusion pressure displayed significantly greater [³H]-2-deoxyglucose-6-P entrapment suggestive of greater MPT pore opening and consistent with greater necrosis and apoptosis. Tempol (SOD mimetic) reduced infarct size in both groups but it remained greater in the higher pressure group. By contrast, uric acid (peroxynitrite scavenger) markedly reduced infarct size at higher pressure, effectively eliminating the differential between the two groups. Inhibition of xanthine oxidase, with allopurinol, reduced infarct size but did not eliminate the differential between the two groups. However, amobarbital (inhibitor of mitochondrial complex I) or apocynin [inhibitor of NAD(P)H oxidase] reduced infarct size at both pressures and also abrogated the differential between the two groups. Consistent with the effect of apocynin, pressure-overloaded hearts displayed significantly higher NAD(P)H oxidase activity. Furthermore, pressure-overloaded hearts displayed increased nitric oxide synthase activity which, along with increased propensity to superoxide generation, may underlie uric acid-induced cardioprotection. In conclusion, increased oxidative and nitrosative stress, coupled with lack of augmented SOD and catalase activities, contributes importantly to the exacerbating impact of pressure overload on MPT pore opening and cell death in ischemic-reperfused hearts.

Mapping the Landscape of Domain-Wall Pinning in Ferromagnetic Films Using Differential Magneto-Optical Microscopy

NASA Astrophysics Data System (ADS)

Badea, Robert; Berezovsky, Jesse

2016-06-01

The propagation of domain walls in a ferromagnetic film is largely determined by domain-wall pinning at defects in the material. In this article, we map the effective potential landscape for domain-wall pinning in permalloy films by raster scanning a single ferromagnetic vortex and monitoring the hysteretic vortex displacement vs applied magnetic field. The measurement is carried out using a differential magneto-optical microscopy technique which yields spatial sensitivity of approximately 10 nm. We present a simple algorithm for extracting an effective pinning potential from the measurement of vortex displacement vs applied field. The resulting maps of the pinning potential reveal distinct types of pinning sites, which we attribute to quasi-zero-, one-, and two-dimensional defects in the permalloy film.

Shaping the Herders' "Mental Maps": Participatory Mapping with Pastoralists' to Understand Their Grazing Area Differentiation and Characterization

NASA Astrophysics Data System (ADS)

Wario, Hussein T.; Roba, Hassan G.; Kaufmann, Brigitte

2015-09-01

Understanding the perception of environmental resources by the users is an important element in planning its sustainable use and management. Pastoralist communities manage their vast grazing territories and exploit resource variability through strategic mobility. However, the knowledge on which pastoralists' resource management is based and their perception of the grazing areas has received limited attention. To improve this understanding and to document this knowledge in a way that can be communicated with `outsiders', we adopted a participatory mapping approach using satellite imagery to explore how Borana pastoralists of southern Ethiopia differentiated and characterized their grazing areas. The Borana herders conceptualized their grazing areas as set of distinctive grazing units each having specific names and characteristics. The precise location and the borders of each grazing unit were identified on the satellite image. In naming of the grazing units, the main differentiating criteria were landforms, vegetation types, prevalence of wildlife species, and manmade features. Based on the dominant soil type, the grazing units were aggregated into seasonal grazing areas that were described using factors such as soil drainage properties, extent of woody cover, main grass species, and prevalence of ecto-parasites. Pastoralists ranking of the seasonal grazing areas according to their suitability for cattle grazing matched with vegetation assessment results on the abundance of desirable fodder varieties. Approaching grazing area differentiation from the pastoralists' perspectives improves the understanding of rangeland characteristics that pastoralists considered important in their grazing management and visualization of their mental representation in digital maps eases communication of this knowledge.

The association between smoking and blood pressure in men: a cross-sectional study.

PubMed

Li, Guoju; Wang, Hailing; Wang, Ke; Wang, Wenrui; Dong, Fen; Qian, Yonggang; Gong, Haiying; Hui, Chunxia; Xu, Guodong; Li, Yanlong; Pan, Li; Zhang, Biao; Shan, Guangliang

2017-10-10

Cigarette smoking is a known risk factor for cardiovascular disease (CVD), but the association between smoking and blood pressure is unclear. Thus, the current study examined the association between cigarette smoking and blood pressure in men. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and pulse pressure (PP) were examined using digital blood pressure measuring device, and smoking status was determined with China National Health Survey. The ANCOVA showed that the adjusted DBP and MAP were lower in current smokers versus nonsmokers and the adjusted SBP was lower in current smokers versus former smokers (P < 0.05). Additionally, the adjusted PP tend to be decreased steadily as the pack·years increased in current smokers. In a fully adjusted logistic regression model, former smokers had increased ORs (95% CI) of 1.48 (1.01, 2.18) of hypertension and current smokers had not increased ORs (95% CI) of 0.83 (0.61, 1.12), compared with never smokers. The findings revealed that the adjusted blood pressure were lower in current smokers versus nonsmokers and former smokers. No significant dose-dependent effect of current smoking on blood pressure indices except PP was observed. Smoking cessation was significantly associated with an increased risk of hypertension. However, current smoking was not a risk factor of hypertension.

cudaMap: a GPU accelerated program for gene expression connectivity mapping.

PubMed

McArt, Darragh G; Bankhead, Peter; Dunne, Philip D; Salto-Tellez, Manuel; Hamilton, Peter; Zhang, Shu-Dong

2013-10-11

Modern cancer research often involves large datasets and the use of sophisticated statistical techniques. Together these add a heavy computational load to the analysis, which is often coupled with issues surrounding data accessibility. Connectivity mapping is an advanced bioinformatic and computational technique dedicated to therapeutics discovery and drug re-purposing around differential gene expression analysis. On a normal desktop PC, it is common for the connectivity mapping task with a single gene signature to take > 2h to complete using sscMap, a popular Java application that runs on standard CPUs (Central Processing Units). Here, we describe new software, cudaMap, which has been implemented using CUDA C/C++ to harness the computational power of NVIDIA GPUs (Graphics Processing Units) to greatly reduce processing times for connectivity mapping. cudaMap can identify candidate therapeutics from the same signature in just over thirty seconds when using an NVIDIA Tesla C2050 GPU. Results from the analysis of multiple gene signatures, which would previously have taken several days, can now be obtained in as little as 10 minutes, greatly facilitating candidate therapeutics discovery with high throughput. We are able to demonstrate dramatic speed differentials between GPU assisted performance and CPU executions as the computational load increases for high accuracy evaluation of statistical significance. Emerging 'omics' technologies are constantly increasing the volume of data and information to be processed in all areas of biomedical research. Embracing the multicore functionality of GPUs represents a major avenue of local accelerated computing. cudaMap will make a strong contribution in the discovery of candidate therapeutics by enabling speedy execution of heavy duty connectivity mapping tasks, which are increasingly required in modern cancer research. cudaMap is open source and can be freely downloaded from http://purl.oclc.org/NET/cudaMap.

Effects of elevated artificial pneumoperitoneum pressure on invasive blood pressure and levels of blood gases.

PubMed

Hypolito, Octavio; Azevedo, João Luiz; Gama, Fernanda; Azevedo, Otavio; Miyahira, Susana Abe; Pires, Oscar César; Caldeira, Fabiana Alvarenga; Silva, Thamiris

2014-01-01

to evaluate the clinical, hemodynamic, gas analysis and metabolic repercussions of high transient pressures of pneumoperitoneum for a short period of time to ensure greater security for introduction of the first trocar. sixty-seven patients undergoing laparoscopic procedures were studied and randomly distributed in P12 group: n=30 (intraperitoneal pressure [IPP] 12mmHg) and P20 group: n=37 (IPP of 20mmHg). Mean arterial pressure (MAP) was evaluated by catheterization of the radial artery; and through gas analysis, pH, partial pressure of oxygen (PaO2), partial pressure of CO2 (PaCO2), bicarbonate (HCO3) and alkalinity (BE) were evaluated. These parameters were measured in both groups at time zero before pneumoperitoneum (TP0); at time 1 (TP1) when IPP reaches 12mmHg in both groups; at time 2 (TP2) after five min with IPP=12mmHg in P12 and after 5min with IPP=20mmHg at P20; and at time 3 (TP3) after 10min with IPP=12mmHg in P12 and with return of IPP from 20 to 12mmHg, starting 10min after TP1 in P20. Different values from those considered normal for all parameters assessed, or the appearance of atypical organic phenomena, were considered as clinical changes. there were statistically significant differences in P20 group in MAP, pH, HCO3 and BE, but within normal limits. No clinical and pathological changes were observed. high and transient intra-abdominal pressure causes changes in MAP, pH, HCO3 and BE, but without any clinical impact on the patient. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Making Large Composite Vessels Without Autoclaves

NASA Technical Reports Server (NTRS)

Sigur, W. A.

1989-01-01

Method for making fiber-reinforced composite structure relies on heating and differential thermal expansion to provide temperature and pressure necessary to develop full strength, without having to place structure in large, expensive autoclave. Layers of differentially expanding material squeeze fiber-reinforce composite between them when heated. Method suitable for such cylindrical structures as pressure vessels and tanks. Used for both resin-matrix and metal-matrix composites.

A conserved pattern of differential expansion of cortical areas in simian primates.

PubMed

Chaplin, Tristan A; Yu, Hsin-Hao; Soares, Juliana G M; Gattass, Ricardo; Rosa, Marcello G P

2013-09-18

The layout of areas in the cerebral cortex of different primates is quite similar, despite significant variations in brain size. However, it is clear that larger brains are not simply scaled up versions of smaller brains: some regions of the cortex are disproportionately large in larger species. It is currently debated whether these expanded areas arise through natural selection pressures for increased cognitive capacity or as a result of the application of a common developmental sequence on different scales. Here, we used computational methods to map and quantify the expansion of the cortex in simian primates of different sizes to investigate whether there is any common pattern of cortical expansion. Surface models of the marmoset, capuchin, and macaque monkey cortex were registered using the software package CARET and the spherical landmark vector difference algorithm. The registration was constrained by the location of identified homologous cortical areas. When comparing marmosets with both capuchins and macaques, we found a high degree of expansion in the temporal parietal junction, the ventrolateral prefrontal cortex, and the dorsal anterior cingulate cortex, all of which are high-level association areas typically involved in complex cognitive and behavioral functions. These expanded maps correlated well with previously published macaque to human registrations, suggesting that there is a general pattern of primate cortical scaling.

Stability analysis of coupled torsional vibration and pressure in oilwell drillstring system

NASA Astrophysics Data System (ADS)

Toumi, S.; Beji, L.; Mlayeh, R.; Abichou, A.

2018-01-01

To address security issues in oilwell drillstring system, the drilling operation handling which is in generally not autonomous but ensured by an operator may be drill bit destructive or fatal for the machine. To control of stick-slip phenomenon, the drillstring control at the right speed taking only the drillstring vibration is not sufficient as the mud dynamics and the pressure change around the drill pipes cannot be neglected. A coupled torsional vibration and pressure model is presented, and the well-posedness problem is addressed. As a Partial Differential Equation-Ordinary Differential Equation (PDE-ODE) coupled system, and in order to maintain a non destructive downhole pressure, we investigate the control stability with and without the damping term in the wave PDE. In terms of, the torsional variable, the downhole pressure, and the annulus pressure, the coupled system equilibrium is shown to be exponentially stable.

Identification and Characterization of Three Differentially Expressed Genes, Encoding S-Adenosylhomocysteine Hydrolase, Methionine Aminopeptidase, and a Histone-Like Protein, in the Toxic Dinoflagellate Alexandrium fundyense†

PubMed Central

Taroncher-Oldenburg, Gaspar; Anderson, Donald M.

2000-01-01

Genes showing differential expression related to the early G1 phase of the cell cycle during synchronized circadian growth of the toxic dinoflagellate Alexandrium fundyense were identified and characterized by differential display (DD). The determination in our previous work that toxin production in Alexandrium is relegated to a narrow time frame in early G1 led to the hypothesis that transcriptionally up- or downregulated genes during this subphase of the cell cycle might be related to toxin biosynthesis. Three genes, encoding S-adenosylhomocysteine hydrolase (Sahh), methionine aminopeptidase (Map), and a histone-like protein (HAf), were isolated. Sahh was downregulated, while Map and HAf were upregulated, during the early G1 phase of the cell cycle. Sahh and Map encoded amino acid sequences with about 90 and 70% similarity to those encoded by several eukaryotic and prokaryotic Sahh and Map genes, respectively. The partial Map sequence also contained three cobalt binding motifs characteristic of all Map genes. HAf encoded an amino acid sequence with 60% similarity to those of two histone-like proteins from the dinoflagellate Crypthecodinium cohnii Biecheler. This study documents the potential of applying DD to the identification of genes that are related to physiological processes or cell cycle events in phytoplankton under conditions where small sample volumes represent an experimental constraint. The identification of an additional 21 genes with various cell cycle-related DD patterns also provides evidence for the importance of pretranslational or transcriptional regulation in dinoflagellates, contrary to previous reports suggesting the possibility that translational mechanisms are the primary means of circadian regulation in this group of organisms. PMID:10788388

mapDIA: Preprocessing and statistical analysis of quantitative proteomics data from data independent acquisition mass spectrometry.

PubMed

Teo, Guoshou; Kim, Sinae; Tsou, Chih-Chiang; Collins, Ben; Gingras, Anne-Claude; Nesvizhskii, Alexey I; Choi, Hyungwon

2015-11-03

Data independent acquisition (DIA) mass spectrometry is an emerging technique that offers more complete detection and quantification of peptides and proteins across multiple samples. DIA allows fragment-level quantification, which can be considered as repeated measurements of the abundance of the corresponding peptides and proteins in the downstream statistical analysis. However, few statistical approaches are available for aggregating these complex fragment-level data into peptide- or protein-level statistical summaries. In this work, we describe a software package, mapDIA, for statistical analysis of differential protein expression using DIA fragment-level intensities. The workflow consists of three major steps: intensity normalization, peptide/fragment selection, and statistical analysis. First, mapDIA offers normalization of fragment-level intensities by total intensity sums as well as a novel alternative normalization by local intensity sums in retention time space. Second, mapDIA removes outlier observations and selects peptides/fragments that preserve the major quantitative patterns across all samples for each protein. Last, using the selected fragments and peptides, mapDIA performs model-based statistical significance analysis of protein-level differential expression between specified groups of samples. Using a comprehensive set of simulation datasets, we show that mapDIA detects differentially expressed proteins with accurate control of the false discovery rates. We also describe the analysis procedure in detail using two recently published DIA datasets generated for 14-3-3β dynamic interaction network and prostate cancer glycoproteome. The software was written in C++ language and the source code is available for free through SourceForge website http://sourceforge.net/projects/mapdia/.This article is part of a Special Issue entitled: Computational Proteomics. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of the postagrogenic transformation of soddy-podzolic soils: Cartographic and analytic support

NASA Astrophysics Data System (ADS)

Sorokina, N. P.; Kozlov, D. N.; Kuznetsova, I. V.

2013-10-01

The results of experimental studies of the postagrogenic transformation of loamy soddy-podzolic soils on the southern slope of the Klin-Dmitrov Moraine Ridge are discussed. A chronosequence of soils (arable soils (cropland)-soils under fallow with meadow vegetation-soils under secondary forests of different ages-soils under a conventionally initial native forest) was examined, and the stages of the postagrogenic transformation of the automorphic soddy-podzolic soils were identified. The differentiation of the former plow horizon into the A1 and A1A2 horizons (according to the differences in the humus content, texture, and acidity) served as the major criterion of the soil transformation. A stage of textural differentiation with clay depletion from the uppermost layer was identified in the soils of the 20- to 60-year-old fallows. The specificity of the postagrogenic transformation of the soils on the slopes was demonstrated. From the methodological point of view, it was important to differentiate between the chronosequences of automorphic and semihydromorphic soils of the leveled interfluves and the soils of the slopes. For this purpose, a series of maps reflecting the history of the land use and the soil cover pattern was analyzed. The cartographic model included the attribute data of the soil surveys, the cartographic sources (a series of historical maps of the land use, topographic maps, remote sensing data, and a digital elevation model), and two base maps: (a) the integral map of the land use and (b) the map of the soil combinations with the separation of the zonal automorphic, semihydromorphic, and erosional soil combinations. This scheme served as a matrix for the organization and analysis of the already available and new materials.

Effect of DA-9701 on Colorectal Distension-Induced Visceral Hypersensitivity in a Rat Model

PubMed Central

Kim, Eun Ran; Min, Byung-Hoon; Lee, Tae Ho; Son, Miwon; Rhee, Poong-Lyul

2014-01-01

Background/Aims DA-9701 is a newly developed drug made from the vegetal extracts of Pharbitidis semen and Co-rydalis tuber. The aim of this study was to evaluate the effect of DA-9701 on colorectal distension (CRD)-induced visceral hypersensitivity in a rat model. Methods Male Sprague-Dawley rats were subjected to neonatal colon irritation (CI) using CRD at 1 week after birth (CI group). At 6 weeks after birth, CRD was applied to these rats with a pressure of 20 to 90 mm Hg, and changes in the mean arterial pressure (MAP) were measured at baseline (i.e., without any drug administration) and after the administration of different doses of DA-9701. Results In the absence of DA-9701, the MAP changes after CRD were significantly higher in the CI group than in the control group at all applied pressures. In the control group, MAP changes after CRD were not significantly affected by the administration of DA-9701. In the CI group, however, the administration of DA-9701 resulted in a significant decrease in MAP changes after CRD. The administration of DA-9701 at a dose of 1.0 mg/kg produced a more significant decrease in MAP changes than the 0.3 mg/kg dose. Conclusions The administration of DA-9701 resulted in a significant increase in pain threshold in rats with CRD-induced visceral hypersensitivity. PMID:25071903

Effect of DA-9701 on colorectal distension-induced visceral hypersensitivity in a rat model.

PubMed

Kim, Eun Ran; Min, Byung-Hoon; Lee, Tae Ho; Son, Miwon; Rhee, Poong-Lyul

2014-07-01

DA-9701 is a newly developed drug made from the vegetal extracts of Pharbitidis semen and Co-rydalis tuber. The aim of this study was to evaluate the effect of DA-9701 on colorectal distension (CRD)-induced visceral hypersensitivity in a rat model. Male Sprague-Dawley rats were subjected to neonatal colon irritation (CI) using CRD at 1 week after birth (CI group). At 6 weeks after birth, CRD was applied to these rats with a pressure of 20 to 90 mm Hg, and changes in the mean arterial pressure (MAP) were measured at baseline (i.e., without any drug administration) and after the administration of different doses of DA-9701. In the absence of DA-9701, the MAP changes after CRD were significantly higher in the CI group than in the control group at all applied pressures. In the control group, MAP changes after CRD were not significantly affected by the administration of DA-9701. In the CI group, however, the administration of DA-9701 resulted in a significant decrease in MAP changes after CRD. The administration of DA-9701 at a dose of 1.0 mg/kg produced a more significant decrease in MAP changes than the 0.3 mg/kg dose. The administration of DA-9701 resulted in a significant increase in pain threshold in rats with CRD-induced visceral hypersensitivity.

Mapping the spatial patterns of field traffic and traffic intensity to predict soil compaction risks at the field scale

NASA Astrophysics Data System (ADS)

Duttmann, Rainer; Kuhwald, Michael; Nolde, Michael

2015-04-01

Soil compaction is one of the main threats to cropland soils in present days. In contrast to easily visible phenomena of soil degradation, soil compaction, however, is obscured by other signals such as reduced crop yield, delayed crop growth, and the ponding of water, which makes it difficult to recognize and locate areas impacted by soil compaction directly. Although it is known that trafficking intensity is a key factor for soil compaction, until today only modest work has been concerned with the mapping of the spatially distributed patterns of field traffic and with the visual representation of the loads and pressures applied by farm traffic within single fields. A promising method for for spatial detection and mapping of soil compaction risks of individual fields is to process dGPS data, collected from vehicle-mounted GPS receivers and to compare the soil stress induced by farm machinery to the load bearing capacity derived from given soil map data. The application of position-based machinery data enables the mapping of vehicle movements over time as well as the assessment of trafficking intensity. It also facilitates the calculation of the trafficked area and the modeling of the loads and pressures applied to soil by individual vehicles. This paper focuses on the modeling and mapping of the spatial patterns of traffic intensity in silage maize fields during harvest, considering the spatio-temporal changes in wheel load and ground contact pressure along the loading sections. In addition to scenarios calculated for varying mechanical soil strengths, an example for visualizing the three-dimensional stress propagation inside the soil will be given, using the Visualization Toolkit (VTK) to construct 2D or 3D maps supporting to decision making due to sustainable field traffic management.

Focus control system for stretched-membrane mirror module

DOEpatents

Butler, B.L.; Beninga, K.J.

1991-05-21

A focus control system dynamically sets and controls the focal length of a reflective membrane supported between a perimeter frame. A rear membrane is also supported between the perimeter frame rearward and spaced apart from a back side of the reflective membrane. The space between the membranes defines a plenum space into which a mass of gas at a first pressure is inserted. The pressure differential between the first pressure and an external pressure, such as the atmospheric pressure, causes the reflective membrane to assume a first curvature relative to a reference plane associated with the perimeter frame. This curvature defines the focal length of the reflective membrane. The focal length is dynamically controlled by changing the volume of the plenum space, thereby changing the first pressure. The system can be used to change or maintain the pressure differential and hence the front membrane curvature. The plenum volume is changed by pushing or pulling on a central section of the rear membrane using a suitable actuator. Sensing means continuously sense the location of the reflective membrane relative to the reference plane. This sensed position is compared to a reference position, and a resulting error signal, comprising the difference between the sensed position and reference position, drives the actuator in a direction to minimize the difference. A vent value compensates for temperature changes or leaks in the closed volume by allowing the pressure differential to be adjusted as required to center the working range of the actuator about the desired focal length. 13 figures.

Focus control system for stretched-membrane mirror module

DOEpatents

Butler, Barry L.; Beninga, Kelly J.

1991-01-01

A focus control system dynamically sets and controls the focal length of a reflective membrane supported between a perimeter frame. A rear membrane is also supported between the perimeter frame rearward and spaced apart from a back side of the reflective membrane. The space between the membranes defines a plenum space into which a mass of gas at a first pressure is inserted. The pressure differential between the first pressure and an external pressure, such as the atmospheric pressure, causes the reflective membrane to assume a first curvature relative to a reference plane associated with the perimeter frame. This curvature defines the focal length of the reflective membrane. The focal length is dynamically controlled by changing the volume of the plenum space, thereby changing the first pressure. The system can be used to change or maintain the pressure differential and hence the front membrane curvature. The plenum volume is changed by pushing or pulling on a central section of the rear membrane using a suitable actuator. Sensing means continuously sense the location of the reflective membrane relative to the reference plane. This sensed position is compared to a reference position, and a resulting error signal, comprising the difference between the sensed position and reference position, drives the actuator in a direction to minimize the difference. A vent value compensates for temperature changes or leaks in the closed volume by allowing the pressure differential to be adjusted as required to center the working range of the actuator about the desired focal length.

Role of proopiomelanocortin neuron Stat3 in regulating arterial pressure and mediating the chronic effects of leptin.

PubMed

Dubinion, John H; do Carmo, Jussara M; Adi, Ahmad; Hamza, Shereen; da Silva, Alexandre A; Hall, John E

2013-05-01

Although signal transducer and activator of transcription 3 (Stat3) is a key second messenger by which leptin regulates appetite and body weight, its role in specific neuronal populations in metabolic regulation and in mediating the chronic effects of leptin on blood pressure is unknown. The current study tested the hypothesis that Stat3 signaling in proopiomelanocortin (POMC) neurons mediates the chronic effects of leptin on mean arterial pressure (MAP), as well as on glucose regulation, energy expenditure, and food intake. Stat3(flox/flox) mice were crossed with POMC-Cre mice to generate mice with Stat3 deletion specifically in POMC neurons (Stat3(flox/flox)/POMC-Cre). Oxygen consumption (Vo2), carbon dioxide respiration (Vco2), motor activity, heat production, food intake, and MAP were measured 24 hours/d. After baseline measurements, leptin was infused (4 μg/kg per min, IP) for 7 days. Stat3(flox/flox)/POMC-Cre mice were hyperphagic, heavier, and had increased respiratory quotients compared with control Stat3(flox/flox) mice. Baseline MAP was not different between the groups, and chronic leptin infusion reduced food intake similarly in both groups (27 versus 29%). Vo2, Vco2, and heat production responses to leptin were not significantly different in control and Stat3(flox/flox)/POMC-Cre mice. However, leptin-mediated increases in MAP were completely abolished, and blood pressure responses to acute air-jet stress were attenuated in male Stat3(flox/flox)/POMC-Cre mice. These results indicate that Stat3 signaling in POMC neurons is essential for leptin-mediated increases in MAP, but not for anorexic or thermogenic effects of leptin.

Identification of differentially expressed genes in cucumber (Cucumis sativus L.) root under waterlogging stress by digital gene expression profile.

PubMed

Qi, Xiao-Hua; Xu, Xue-Wen; Lin, Xiao-Jian; Zhang, Wen-Jie; Chen, Xue-Hao

2012-03-01

High-throughput tag-sequencing (Tag-seq) analysis based on the Solexa Genome Analyzer platform was applied to analyze the gene expression profiling of cucumber plant at 5 time points over a 24h period of waterlogging treatment. Approximately 5.8 million total clean sequence tags per library were obtained with 143013 distinct clean tag sequences. Approximately 23.69%-29.61% of the distinct clean tags were mapped unambiguously to the unigene database, and 53.78%-60.66% of the distinct clean tags were mapped to the cucumber genome database. Analysis of the differentially expressed genes revealed that most of the genes were down-regulated in the waterlogging stages, and the differentially expressed genes mainly linked to carbon metabolism, photosynthesis, reactive oxygen species generation/scavenging, and hormone synthesis/signaling. Finally, quantitative real-time polymerase chain reaction using nine genes independently verified the tag-mapped results. This present study reveals the comprehensive mechanisms of waterlogging-responsive transcription in cucumber. Copyright © 2011 Elsevier Inc. All rights reserved.

Hexamethonium attenuates sympathetic activity and blood pressure in spontaneously hypertensive rats.

PubMed

Li, Peng; Gong, Jue-Xiao; Sun, Wei; Zhou, Bin; Kong, Xiang-Qing

2015-11-01

Sympathetic activity is enhanced in heart failure and hypertensive rats. The aims of the current study were: i) To investigate the association between renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) in response to intravenous injection of the ganglionic blocker hexamethonium; and ii) to determine whether normal Wistar rats and spontaneously hypertensive rats (SHRs) differ in their response to hexamethonium. RSNA and MAP were recorded in anaesthetized rats. Intravenous injection of four doses of hexamethonium significantly reduced the RSNA, MAP and heart rate (HR) in the Wistar rats and SHRs. There were no significant differences in the RSNA, MAP or HR between Wistar rats and SHRs at the two lowest doses of hexamethonium. However, the two highest doses of hexamethonium resulted in a greater reduction in the RSNA and MAP in SHRs compared with Wistar rats. There was a significant positive correlation between the alterations in RSNA and MAP in response to the intravenous injection of hexamethonium in the Wistar rats and SHRs. There were no significant differences in the timing of the maximal effects on RSNA, MAP or HR or in recovery following hexamethonium treatment. These results suggest that there is an association between the RSNA and MAP response to intravenous injection of hexamethonium and that the alterations in MAP in response to hexamethonium may be used to evaluate basal sympathetic nerve activity.

PodNet, a protein-protein interaction network of the podocyte.

PubMed

Warsow, Gregor; Endlich, Nicole; Schordan, Eric; Schordan, Sandra; Chilukoti, Ravi K; Homuth, Georg; Moeller, Marcus J; Fuellen, Georg; Endlich, Karlhans

2013-07-01

Interactions between proteins crucially determine cellular structure and function. Differential analysis of the interactome may help elucidate molecular mechanisms during disease development; however, this analysis necessitates mapping of expression data on protein-protein interaction networks. These networks do not exist for the podocyte; therefore, we built PodNet, a literature-based mouse podocyte network in Cytoscape format. Using database protein-protein interactions, we expanded PodNet to XPodNet with enhanced connectivity. In order to test the performance of XPodNet in differential interactome analysis, we examined podocyte developmental differentiation and the effect of cell culture. Transcriptomes of podocytes in 10 different states were mapped on XPodNet and analyzed with the Cytoscape plugin ExprEssence, based on the law of mass action. Interactions between slit diaphragm proteins are most significantly upregulated during podocyte development and most significantly downregulated in culture. On the other hand, our analysis revealed that interactions lost during podocyte differentiation are not regained in culture, suggesting a loss rather than a reversal of differentiation for podocytes in culture. Thus, we have developed PodNet as a valuable tool for differential interactome analysis in podocytes, and we have identified established and unexplored regulated interactions in developing and cultured podocytes.

14 CFR 25.365 - Pressurized compartment loads.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Pressurized compartment loads. For airplanes with one or more pressurized compartments the following apply: (a... differential loads from zero up to the maximum relief valve setting. (b) The external pressure distribution in... zero up to the maximum allowed during landing. (d) The airplane structure must be designed to be able...

How to Differentiate an Integer Modulo n

ERIC Educational Resources Information Center

Emmons, Caleb; Krebs, Mike; Shaheen, Anthony

2009-01-01

A number derivative is a numerical mapping that satisfies the product rule. In this paper, we determine all number derivatives on the set of integers modulo n. We also give a list of undergraduate research projects to pursue using these maps as a starting point.

Mapping vegetation communities using statistical data fusion in the Ozark National Scenic Riverways, Missouri, USA

USGS Publications Warehouse

Chastain, R.A.; Struckhoff, M.A.; He, H.S.; Larsen, D.R.

2008-01-01

A vegetation community map was produced for the Ozark National Scenic Riverways consistent with the association level of the National Vegetation Classification System. Vegetation communities were differentiated using a large array of variables derived from remote sensing and topographic data, which were fused into independent mathematical functions using a discriminant analysis classification approach. Remote sensing data provided variables that discriminated vegetation communities based on differences in color, spectral reflectance, greenness, brightness, and texture. Topographic data facilitated differentiation of vegetation communities based on indirect gradients (e.g., landform position, slope, aspect), which relate to variations in resource and disturbance gradients. Variables derived from these data sources represent both actual and potential vegetation community patterns on the landscape. A hybrid combination of statistical and photointerpretation methods was used to obtain an overall accuracy of 63 percent for a map with 49 vegetation community and land-cover classes, and 78 percent for a 33-class map of the study area.

Comparison of aortic and carotid baroreflex stimulus-response characteristics in humans

NASA Technical Reports Server (NTRS)

Smith, S. A.; Querry, R. G.; Fadel, P. J.; Weiss, M. W.; Olivencia-Yurvati, A.; Shi, X.; Raven, P. B.

2001-01-01

In order to characterize the stimulus-response relationships of the arterial, aortic, and carotid baroreflexes in mediating cardiac chronotropic function, we measured heart rate (HR) responses elicited by acute changes in mean arterial pressure (MAP) and carotid sinus pressure (CSP) in 11 healthy individuals. Arterial (aortic + carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of phenylephrine (PE) and sodium nitroprusside (SN). To assess aortic-cardiac responses, neck pressure (NP) and suction (NS) were applied during PE and SN administration, respectively, to counter alterations in CSP thereby isolating the aortic baroreflex. Graded levels of NP and NS were delivered to the carotid sinus using a customized neck collar device to assess the carotid-cardiac baroreflex, independent of drug infusion. The operating characteristics of each reflex were determined from the logistic function of the elicited HR response to the induced change in MAP. The arterial pressures at which the threshold was located on the stimulus-response curves determined for the arterial, aortic and carotid baroreflexes were not significantly different (72+/-4, 67+/-3, and 72+/-4 mm Hg, respectively, P > 0.05). Similarly, the MAP at which the saturation of the reflex responses were elicited did not differ among the baroreflex arcs examined (98+/-3, 99+/-2, and 102+/-3 mm Hg, respectively). These data suggest that the baroreceptor populations studied operate over the same range of arterial pressures. This finding indicates each baroreflex functions as both an important anti-hypotensive and anti-hypertensive mechanism. In addition, this investigation describes a model of aortic baroreflex function in normal healthy humans, which may prove useful in identifying the origin of baroreflex dysfunction in disease- and training-induced conditions.

Relationship between long-term exposure to low-level arsenic in drinking water and the prevalence of abnormal blood pressure.

PubMed

Zhang, Chuanwu; Mao, Guangyun; He, Suxia; Yang, Zuopeng; Yang, Wei; Zhang, Xiaojing; Qiu, Wenting; Ta, Na; Cao, Li; Yang, Hui; Guo, Xiaojuan

2013-11-15

Arsenic increases the risk and incidence of cardiovascular disease. To explore the impact of long-term exposure to low-level arsenic in drinking water on blood pressure including pulse pressure (PP) and mean arterial blood pressure (MAP), a cross-sectional study was conducted in 2010 in which the blood pressure of 405 villagers was measured, who had been drinking water with an inorganic arsenic content <50 μg/L. A multivariate logistic regression model was used to estimate odds ratios and 95% confidence intervals. After adjusting for age, gender, Body Mass Index (BMI), alcohol consumption and smoking, the odds ratios showed a 1.45-fold (95%CI: 0.63-3.35) increase in the group with >30-50 years of arsenic exposure and a 2.95-fold (95%CI: 1.31-6.67) increase in the group with >50 years exposure. Furthermore, the odds ratio for prevalence of abnormal PP and MAP were 1.06 (95%CI: 0.24-4.66) and 0.87 (95%CI: 0.36-2.14) in the group with >30-50 years of exposure, and were 2.46 (95%CI: 0.87-6.97) and 3.75 (95%CI: 1.61-8.71) for the group with >50 years exposure, compared to the group with arsenic exposure ≤ 30 years respectively. Significant trends for Hypertension (p<0.0001), PP (p<0.0001) and MAP (p=0.0016) were found. The prevalence of hypertension and abnormal PP as well as MAP is marked among a low-level arsenic exposure population, and significantly increases with the duration of arsenic exposure. Copyright © 2012 Elsevier B.V. All rights reserved.

Investigation on the energy absorption performance of a fixed-bottom pressure-differential wave energy converter

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

Babarit, A.; Wendt, F.; Yu, Y. -H.

2017-04-01

In this article, we investigate the energy absorption performance of a fixed-bottom pressure-differential wave energy converter. Two versions of the technology are considered: one has the moving surfaces on the bottom of the air chambers whereas the other has the moving surfaces on the top. We developed numerical models in the frequency domain, thereby enabling the power absorption of the two versions of the device to be assessed. It is observed that the moving surfaces on the top allow for easier tuning of the natural period of the system. Taking into account stroke limitations, the design is optimized. Results indicatemore » that the pressure-differential wave energy converter is a highly efficient technology both with respect to energy absorption and selected economic performance indicators.« less

Leak Rate Quantification Method for Gas Pressure Seals with Controlled Pressure Differential

NASA Technical Reports Server (NTRS)

Daniels, Christopher C.; Braun, Minel J.; Oravec, Heather A.; Mather, Janice L.; Taylor, Shawn C.

2015-01-01

An enhancement to the pressure decay leak rate method with mass point analysis solved deficiencies in the standard method. By adding a control system, a constant gas pressure differential across the test article was maintained. As a result, the desired pressure condition was met at the onset of the test, and the mass leak rate and measurement uncertainty were computed in real-time. The data acquisition and control system were programmed to automatically stop when specified criteria were met. Typically, the test was stopped when a specified level of measurement uncertainty was attained. Using silicone O-ring test articles, the new method was compared with the standard method that permitted the downstream pressure to be non-constant atmospheric pressure. The two methods recorded comparable leak rates, but the new method recorded leak rates with significantly lower measurement uncertainty, statistical variance, and test duration. Utilizing this new method in leak rate quantification, projects will reduce cost and schedule, improve test results, and ease interpretation between data sets.

Pressure measurement in supersonic air flow by differential absorptive laser-induced thermal acoustics.

PubMed

Hart, Roger C; Herring, G C; Balla, R Jeffrey

2007-06-15

Nonintrusive, off-body flow barometry in Mach 2 airflow has been demonstrated in a large-scale supersonic wind tunnel using seedless laser-induced thermal acoustics (LITA). The static pressure of the gas flow is determined with a novel differential absorption measurement of the ultrasonic sound produced by the LITA pump process. Simultaneously, the streamwise velocity and static gas temperature of the same spatially resolved sample volume were measured with this nonresonant time-averaged LITA technique. Mach number, temperature, and pressure have 0.2%, 0.4%, and 4% rms agreement, respectively, in comparison with known free-stream conditions.

Pressure Measurement in Supersonic Air Flow by Differential Absorptive Laser-Induced Thermal Acoustics

NASA Technical Reports Server (NTRS)

Hart, Roger C.; Herring, Gregory C.; Balla, Robert J.

2007-01-01

Nonintrusive, off-body flow barometry in Mach-2 airflow has been demonstrated in a large-scale supersonic wind tunnel using seedless laser-induced thermal acoustics (LITA). The static pressure of the gas flow is determined with a novel differential absorption measurement of the ultrasonic sound produced by the LITA pump process. Simultaneously, stream-wise velocity and static gas temperature of the same spatially-resolved sample volume were measured with this nonresonant time-averaged LITA technique. Mach number, temperature and pressure have 0.2%, 0.4%, and 4% rms agreement, respectively, in comparison with known free-stream conditions.

Differentiation of orbital lymphoma and idiopathic orbital inflammatory pseudotumor: combined diagnostic value of conventional MRI and histogram analysis of ADC maps.

PubMed

Ren, Jiliang; Yuan, Ying; Wu, Yingwei; Tao, Xiaofeng

2018-05-02

The overlap of morphological feature and mean ADC value restricted clinical application of MRI in the differential diagnosis of orbital lymphoma and idiopathic orbital inflammatory pseudotumor (IOIP). In this paper, we aimed to retrospectively evaluate the combined diagnostic value of conventional magnetic resonance imaging (MRI) and whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in the differentiation of the two lesions. In total, 18 patients with orbital lymphoma and 22 patients with IOIP were included, who underwent both conventional MRI and diffusion weighted imaging before treatment. Conventional MRI features and histogram parameters derived from ADC maps, including mean ADC (ADC mean ), median ADC (ADC median ), skewness, kurtosis, 10th, 25th, 75th and 90th percentiles of ADC (ADC 10 , ADC 25 , ADC 75 , ADC 90 ) were evaluated and compared between orbital lymphoma and IOIP. Multivariate logistic regression analysis was used to identify the most valuable variables for discriminating. Differential model was built upon the selected variables and receiver operating characteristic (ROC) analysis was also performed to determine the differential ability of the model. Multivariate logistic regression showed ADC 10 (P = 0.023) and involvement of orbit preseptal space (P = 0.029) were the most promising indexes in the discrimination of orbital lymphoma and IOIP. The logistic model defined by ADC 10 and involvement of orbit preseptal space was built, which achieved an AUC of 0.939, with sensitivity of 77.30% and specificity of 94.40%. Conventional MRI feature of involvement of orbit preseptal space and ADC histogram parameter of ADC 10 are valuable in differential diagnosis of orbital lymphoma and IOIP.

Controlled Tests of Eductors and Submersible Pumps

DTIC Science & Technology

1994-09-01

5 1. " 20 25 3 0 510 15 20 25 30 Time (min) Plate B63 Slurry Specific Gravity H & H Submersible Pump Clean Sand Test 1 2 I S-SG Densit MeterI SG...22 Using Differential Pressure to Measure Specific Gravity ...... .32 4-Conclusions and Recommendations ..................... 34 References...33 Figure 21. Comparison of specific gravity of the slurry as measured by the nuclear density meter and differential pressure

Numerical evaluation of the skull for human neuromodulation with transcranial focused ultrasound

NASA Astrophysics Data System (ADS)

Mueller, Jerel K.; Ai, Leo; Bansal, Priya; Legon, Wynn

2017-12-01

Objective. Transcranial focused ultrasound is an emerging field for human non-invasive neuromodulation, but its dosing in humans is difficult to know due to the skull. The objective of the present study was to establish modeling methods based on medical images to assess skull differences between individuals on the wave propagation of ultrasound. Approach. Computational models of transcranial focused ultrasound were constructed using CT and MR scans to solve for intracranial pressure. We explored the effect of including the skull base in models, different transducer placements on the head, and differences between 250 kHz or 500 kHz acoustic frequency for both female and male models. We further tested these features using linear, nonlinear, and elastic simulations. To better understand inter-subject skull thickness and composition effects we evaluated the intracranial pressure maps between twelve individuals at two different skull sites. Main results. Nonlinear acoustic simulations resulted in virtually identical intracranial pressure maps with linear acoustic simulations. Elastic simulations showed a difference in max pressures and full width half maximum volumes of 15% at most. Ultrasound at an acoustic frequency of 250 kHz resulted in the creation of more prominent intracranial standing waves compared to 500 kHz. Finally, across twelve model human skulls, a significant linear relationship to characterize intracranial pressure maps was not found. Significance. Despite its appeal, an inherent problem with the use of a noninvasive transcranial ultrasound method is the difficulty of knowing intracranial effects because of the skull. Here we develop detailed computational models derived from medical images of individuals to simulate the propagation of neuromodulatory ultrasound across the skull and solve for intracranial pressure maps. These methods allow for a much better understanding of the intracranial effects of ultrasound for an individual in order to ensure proper targeting and more tightly control dosing.

Quantitative Skeletal Muscle MRI: Part 2, MR Spectroscopy and T2 Relaxation Time Mapping-Comparison Between Boys With Duchenne Muscular Dystrophy and Healthy Boys.

PubMed

Kim, Hee Kyung; Serai, Suraj; Lindquist, Diana; Merrow, Arnold C; Horn, Paul S; Kim, Dong Hoon; Wong, Brenda L

2015-08-01

The purpose of this study is to validate the use of MR spectroscopy (MRS) in measuring muscular fat and to compare it with T2 maps in differentiating boys with Duchenne muscular dystrophy (DMD) from healthy boys. Forty-two boys with DMD and 31 healthy boys were evaluated with MRI with (1)H-MRS and T2 maps. Grading of muscle fat and edema on conventional images, calculation of fat fractions ([fat / fat] + water) on MRS, and calculation of T2 fat values on T2 maps of the gluteus maximus and vastus lateralis muscles were performed. Group comparisons were made. The 95% reference interval (RI) of fat fraction for the control group was applied and compared with T2 map results. Minimal fat on T1-weighted images was seen in 90.3% (gluteus maximus) and 71.0% (vastus lateralis) of healthy boys, versus 33.3% (gluteus maximus) and 52.4% (vastus lateralis) of boys with DMD. Muscle edema was seen in none of the healthy boys versus 52.4% (gluteus maximus) and 57.1% (vastus lateralis) of the boys with DMD. Fat fractions were higher in the DMD group (52.7%, gluteus maximus; 27.3%, vastus lateralis) than in the control group (12.8%, gluteus maximus; 13.7%, vastus lateralis) (p < 0.001). The 95% RI for gluteus maximus (38.7%) resulted in 61.9% sensitivity and 100% specificity for differentiating boys with DMD from healthy boys, whereas the value for vastus lateralis (17.8%) resulted in 76.2% sensitivity and 100% specificity; both had lower accuracy than did T2 maps (100% sensitivity and specificity). There was a positive correlation between T2 fat values and fat fractions (p < 0.0001). In differentiation of the two groups, T2 maps were more accurate than MRS. Fat fractions can underestimate the actual amount of fat because of coexisting muscle edema in DMD.

Hydrogen bonding Part 53. Correlation of differential scanning calorimetric data with IR and dissociation vapor pressure studies of transitions of hexamethonium chloride and bromide dihydrates and hexamethonium bromide monohydrate

NASA Astrophysics Data System (ADS)

Snider, Barbara L.; Harmon, Kenneth M.

1994-03-01

Differential scanning calorimetry of hexamethonium chloride dihydrate shows an endothermic transition of 2.70 kcal mol -1 at 36.81°C. This correlates well with the temperatures observed by IR spectra (36°C) and equilibrium dissociation vapor pressure studies (37°C) for the transition between Type I planar cluster and Type II extended linear HOH⋯Cl - hydrogen bonding, and with the value of 2.77 kcal mol -1 for this transition derived by Hess' law treatment of dissociation vapor pressure data. Differential scanning calorimetry of hexamethonium bromide shows a rapid endothermic transition of 2.38 kcal mol -1 at 35.15°C and a very slow endothermic transition of about 12-13 kcal mol -1 centered near 50°C. This latter endotherm corresponds to the transition between Type I and Type II HOH⋯Br - hydrogen bonding observed by IR and vapor pressure studies at 49°C. The nature of the 35.15°C endotherm is not known. Hexamethonium bromide also shows a third endotherm at 142.91°C, which presumably results from melting of hydrate in the sealed DSC cell. Combined analysis of differential scanning calorimetry and dissociation vapor pressure data predicts a value of about -13 kcal mol -1 for an exothermic disproportionation at 52°C of two hexamethonium bromide monohydrate to Type II dihydrate and anhydrous bromide.

Deploying QTL-seq for rapid delineation of a potential candidate gene underlying major trait-associated QTL in chickpea

PubMed Central

Das, Shouvik; Upadhyaya, Hari D.; Bajaj, Deepak; Kujur, Alice; Badoni, Saurabh; Laxmi; Kumar, Vinod; Tripathi, Shailesh; Gowda, C. L. Laxmipathi; Sharma, Shivali; Singh, Sube; Tyagi, Akhilesh K.; Parida, Swarup K.

2015-01-01

A rapid high-resolution genome-wide strategy for molecular mapping of major QTL(s)/gene(s) regulating important agronomic traits is vital for in-depth dissection of complex quantitative traits and genetic enhancement in chickpea. The present study for the first time employed a NGS-based whole-genome QTL-seq strategy to identify one major genomic region harbouring a robust 100-seed weight QTL using an intra-specific 221 chickpea mapping population (desi cv. ICC 7184 × desi cv. ICC 15061). The QTL-seq-derived major SW QTL (CaqSW1.1) was further validated by single-nucleotide polymorphism (SNP) and simple sequence repeat (SSR) marker-based traditional QTL mapping (47.6% R2 at higher LOD >19). This reflects the reliability and efficacy of QTL-seq as a strategy for rapid genome-wide scanning and fine mapping of major trait regulatory QTLs in chickpea. The use of QTL-seq and classical QTL mapping in combination narrowed down the 1.37 Mb (comprising 177 genes) major SW QTL (CaqSW1.1) region into a 35 kb genomic interval on desi chickpea chromosome 1 containing six genes. One coding SNP (G/A)-carrying constitutive photomorphogenic9 (COP9) signalosome complex subunit 8 (CSN8) gene of these exhibited seed-specific expression, including pronounced differential up-/down-regulation in low and high seed weight mapping parents and homozygous individuals during seed development. The coding SNP mined in this potential seed weight-governing candidate CSN8 gene was found to be present exclusively in all cultivated species/genotypes, but not in any wild species/genotypes of primary, secondary and tertiary gene pools. This indicates the effect of strong artificial and/or natural selection pressure on target SW locus during chickpea domestication. The proposed QTL-seq-driven integrated genome-wide strategy has potential to delineate major candidate gene(s) harbouring a robust trait regulatory QTL rapidly with optimal use of resources. This will further assist us to extrapolate the molecular mechanism underlying complex quantitative traits at a genome-wide scale leading to fast-paced marker-assisted genetic improvement in diverse crop plants, including chickpea. PMID:25922536

Characterizing fishing effort and spatial extent of coastal fisheries.

PubMed

Stewart, Kelly R; Lewison, Rebecca L; Dunn, Daniel C; Bjorkland, Rhema H; Kelez, Shaleyla; Halpin, Patrick N; Crowder, Larry B

2010-12-29

Biodiverse coastal zones are often areas of intense fishing pressure due to the high relative density of fishing capacity in these nearshore regions. Although overcapacity is one of the central challenges to fisheries sustainability in coastal zones, accurate estimates of fishing pressure in coastal zones are limited, hampering the assessment of the direct and collateral impacts (e.g., habitat degradation, bycatch) of fishing. We compiled a comprehensive database of fishing effort metrics and the corresponding spatial limits of fisheries and used a spatial analysis program (FEET) to map fishing effort density (measured as boat-meters per km²) in the coastal zones of six ocean regions. We also considered the utility of a number of socioeconomic variables as indicators of fishing pressure at the national level; fishing density increased as a function of population size and decreased as a function of coastline length. Our mapping exercise points to intra and interregional 'hotspots' of coastal fishing pressure. The significant and intuitive relationships we found between fishing density and population size and coastline length may help with coarse regional characterizations of fishing pressure. However, spatially-delimited fishing effort data are needed to accurately map fishing hotspots, i.e., areas of intense fishing activity. We suggest that estimates of fishing effort, not just target catch or yield, serve as a necessary measure of fishing activity, which is a key link to evaluating sustainability and environmental impacts of coastal fisheries.

A comparative study of RNA-Seq and microarray data analysis on the two examples of rectal-cancer patients and Burkitt Lymphoma cells.

PubMed

Wolff, Alexander; Bayerlová, Michaela; Gaedcke, Jochen; Kube, Dieter; Beißbarth, Tim

2018-01-01

Pipeline comparisons for gene expression data are highly valuable for applied real data analyses, as they enable the selection of suitable analysis strategies for the dataset at hand. Such pipelines for RNA-Seq data should include mapping of reads, counting and differential gene expression analysis or preprocessing, normalization and differential gene expression in case of microarray analysis, in order to give a global insight into pipeline performances. Four commonly used RNA-Seq pipelines (STAR/HTSeq-Count/edgeR, STAR/RSEM/edgeR, Sailfish/edgeR, TopHat2/Cufflinks/CuffDiff)) were investigated on multiple levels (alignment and counting) and cross-compared with the microarray counterpart on the level of gene expression and gene ontology enrichment. For these comparisons we generated two matched microarray and RNA-Seq datasets: Burkitt Lymphoma cell line data and rectal cancer patient data. The overall mapping rate of STAR was 98.98% for the cell line dataset and 98.49% for the patient dataset. Tophat's overall mapping rate was 97.02% and 96.73%, respectively, while Sailfish had only an overall mapping rate of 84.81% and 54.44%. The correlation of gene expression in microarray and RNA-Seq data was moderately worse for the patient dataset (ρ = 0.67-0.69) than for the cell line dataset (ρ = 0.87-0.88). An exception were the correlation results of Cufflinks, which were substantially lower (ρ = 0.21-0.29 and 0.34-0.53). For both datasets we identified very low numbers of differentially expressed genes using the microarray platform. For RNA-Seq we checked the agreement of differentially expressed genes identified in the different pipelines and of GO-term enrichment results. In conclusion the combination of STAR aligner with HTSeq-Count followed by STAR aligner with RSEM and Sailfish generated differentially expressed genes best suited for the dataset at hand and in agreement with most of the other transcriptomics pipelines.

Geomorphology and depositional subenvironments of Gulf Islands National Seashore, Perdido Key and Santa Rosa Island, Florida

USGS Publications Warehouse

Morton, Robert A.; Montgomery, Marilyn C.

2010-01-01

The primary mapping procedures were supervised functions within a Geographic Information System (GIS) that were applied to delineate and classify depositional subenvironments and features, collectively referred to as map units. The delineated boundaries of the map units were exported to create one shapefile, and are differentiated by the field "Type" in the associated attribute table. Map units were delineated and classified based on differences in tonal patterns of features in contrast to adjacent features observed on orthophotography. Land elevations from recent lidar surveys served as supplementary data to assist in delineating the map unit boundaries.

Effects of Aging and Environmental Conditions on Ammunition/Explosives Storage Magazines - Paper 2

DTIC Science & Technology

2010-07-01

characterized as destructive. The destructive category is apparently limited to reactions with impure dolomitic aggregates and are a result of either...extreme pressures that eventually overcome the tensile strength of the structure. These pressures will cause spalling, map cracking, discoloration, or...fill with this gel and expand to create extreme tensile pressures . These pressures cause micro-scale cracking and eventually develop into

24 CFR 200.926e - Supplemental information for use with the CABO One and Two Family Dwelling Code.

Code of Federal Regulations, 2014 CFR

2014-04-01

... shall be in accordance with section 7 of ASCE 7-88. (c) Wind pressures. The minimum Design Wind Pressures (net pressures) set forth below apply to areas designated as experiencing basic wind speeds up to and including 80 mph, as shown in ASCE 7-88, Figure 1, Basic Wind Speed Map. These pressures also...

24 CFR 200.926e - Supplemental information for use with the CABO One and Two Family Dwelling Code.

Code of Federal Regulations, 2013 CFR

2013-04-01

... shall be in accordance with section 7 of ASCE 7-88. (c) Wind pressures. The minimum Design Wind Pressures (net pressures) set forth below apply to areas designated as experiencing basic wind speeds up to and including 80 mph, as shown in ASCE 7-88, Figure 1, Basic Wind Speed Map. These pressures also...

24 CFR 200.926e - Supplemental information for use with the CABO One and Two Family Dwelling Code.

Code of Federal Regulations, 2012 CFR

2012-04-01

... shall be in accordance with section 7 of ASCE 7-88. (c) Wind pressures. The minimum Design Wind Pressures (net pressures) set forth below apply to areas designated as experiencing basic wind speeds up to and including 80 mph, as shown in ASCE 7-88, Figure 1, Basic Wind Speed Map. These pressures also...

24 CFR 200.926e - Supplemental information for use with the CABO One and Two Family Dwelling Code.

Code of Federal Regulations, 2010 CFR

2010-04-01

... shall be in accordance with section 7 of ASCE 7-88. (c) Wind pressures. The minimum Design Wind Pressures (net pressures) set forth below apply to areas designated as experiencing basic wind speeds up to and including 80 mph, as shown in ASCE 7-88, Figure 1, Basic Wind Speed Map. These pressures also...

24 CFR 200.926e - Supplemental information for use with the CABO One and Two Family Dwelling Code.

Code of Federal Regulations, 2011 CFR

2011-04-01

... shall be in accordance with section 7 of ASCE 7-88. (c) Wind pressures. The minimum Design Wind Pressures (net pressures) set forth below apply to areas designated as experiencing basic wind speeds up to and including 80 mph, as shown in ASCE 7-88, Figure 1, Basic Wind Speed Map. These pressures also...

The role of non-thermal atmospheric pressure biocompatible plasma in the differentiation of osteoblastic precursor cells, MC3T3-E1.

PubMed

Han, Ihn; Choi, Eun Ha

2017-05-30

Non-thermal atmospheric pressure plasma is ionized matter, composed of highly reactive species that include positive ions, negative ions, free radicals, neutral atoms, and molecules. Recent reports have suggested that non-thermal biocompatible plasma (NBP) can selectively kill a variety of cancer cells, and promote stem cell differentiation. However as of yet, the regulation of proliferation and differentiation potential of NBP has been poorly understood.Here, we investigated the effects of NBP on the osteogenic differentiation of precursor cell lines of osteoblasts, MC3T3 E1 and SaOS-2. For in vitro osteogenic differentiation, precursor cell lines were treated with NBP, and cultured with osteogenic induction medium. After 10 days of treatment, the NBP was shown to be effective in osteogenic differentiation in MC3T3 E1 cells by von Kossa and Alizarin Red S staining assay. Real-time PCR was then performed to investigate the expression of osteogenic specific genes, Runx2, OCN, COL1, ALP and osterix in MC3T3 E1 cells after treatment with NBP for 4 days. Furthermore, analysis of the protein expression showed that NBP treatment significantly reduced PI3K/AKT signaling and MAPK family signaling. However, p38 controlled phosphorylation of transcription factor forkhead box O1 (FoxO1) that related to cell differentiation with increased phosphorylated p38. These results suggest that non-thermal atmospheric pressure plasma can induce osteogenic differentiation, and enhance bone formation.

Role of Salt, Pressure, and Water Activity on Homogeneous Ice Nucleation.

PubMed

Espinosa, Jorge R; Soria, Guiomar D; Ramirez, Jorge; Valeriani, Chantal; Vega, Carlos; Sanz, Eduardo

2017-09-21

Pure water can be substantially supercooled below the melting temperature without transforming into ice. The achievable supercooling can be enhanced by adding solutes or by applying hydrostatic pressure. Avoiding ice formation is of great importance in the cryopreservation of food or biological samples. In this Letter, we investigate the similarity between the effects of pressure and salt on ice formation using a combination of state-of-the-art simulation techniques. We find that both hinder ice formation by increasing the energetic cost of creating the ice-fluid interface. Moreover, we examine the widely accepted proposal that the ice nucleation rate for different pressures and solute concentrations can be mapped through the activity of water [ Koop , L. ; Tsias , P. Nature , 2000 , 406 , 611 ]. We show that such a proposal is not consistent with the nucleation rates predicted in our simulations because it does not include all parameters affecting ice nucleation. Therefore, even though salt and pressure have a qualitatively similar effect on ice formation, they cannot be quantitatively mapped onto one another.

Optical fiber Bragg grating-instrumented silicone liner for interface pressure measurement within prosthetic sockets of lower-limb amputees

NASA Astrophysics Data System (ADS)

Al-Fakih, Ebrahim; Arifin, Nooranida; Pirouzi, Gholamhossein; Mahamd Adikan, Faisal Rafiq; Shasmin, Hanie Nadia; Abu Osman, Noor Azuan

2017-08-01

This paper presents a fiber Bragg grating (FBG)-instrumented prosthetic silicone liner that provides cushioning for the residual limb and can successfully measure interface pressures inside prosthetic sockets of lower-limb amputees in a simple and practical means of sensing. The liner is made of two silicone layers between which 12 FBG sensors were embedded at locations of clinical interest. The sensors were then calibrated using a custom calibration platform that mimics a real-life situation. Afterward, a custom gait simulating machine was built to test the liner performance during an amputee's simulated gait. To validate the findings, the results were compared to those obtained by the commonly used F-socket mats. As the statistical findings reveal, both pressure mapping methods measured the interface pressure in a consistent way, with no significant difference (P-values ≥0.05). This pressure mapping technique in the form of a prosthetic liner will allow prosthetics professionals to quickly and accurately create an overall picture of the interface pressure distribution inside sockets in research and clinical settings, thereby improving the socket fit and amputee's satisfaction.

The First Slow Step: Differential Effects of Object and Word-Form Familiarization on Retention of Fast-Mapped Words

ERIC Educational Resources Information Center

Kucker, Sarah C.; Samuelson, Larissa K.

2012-01-01

Recent research demonstrated that although 24-month-old infants do well on the initial pairing of a novel word and novel object in fast-mapping tasks, they are unable to retain the mapping after a 5 min delay. The current study examines the role of familiarity with the objects and words on infants' ability to bridge between the initial fast…

Comparison of remote sensing indices for monitoring of desert cienegas

USGS Publications Warehouse

Wilson, Natalie R.; Norman, Laura M.; Villarreal, Miguel; Gass, Leila; Tiller, Ron; Salywon, Andrew

2016-01-01

This research considers the applicability of different vegetation indices at 30 m resolution for mapping and monitoring desert wetland (cienega) health and spatial extent through time at Cienega Creek in southeastern Arizona, USA. Multiple stressors including the risk of decadal-scale drought, the effects of current and predicted global warming, and continued anthropogenic pressures threaten aquatic habitats in the southwest and cienegas are recognized as important sites for conservation and restoration efforts. However, cienegas present a challenge to satellite-imagery based analysis due to their small size and mixed surface cover of open water, exposed soils, and vegetation. We created time series of five well-known vegetation indices using annual Landsat Thematic Mapper (TM) images retrieved during the April–June dry season, from 1984 to 2011 to map landscape-level distribution of wetlands and monitor the temporal dynamics of individual sites. Indices included the Normalized Difference Vegetation Index (NDVI), the Soil-Adjusted Vegetation Index (SAVI), the Normalized Difference Water Index (NDWI), and the Normalized Difference Infrared Index (NDII). One topographic index, the Topographic Wetness Index (TWI), was analyzed to examine the utility of topography in mapping distribution of cienegas. Our results indicate that the NDII, calculated using Landsat TM band 5, outperforms the other indices at differentiating cienegas from riparian and upland sites, and was the best means to analyze change. As such, it offers a critical baseline for future studies that seek to extend the analysis of cienegas to other regions and time scales, and has broader applicability to the remote sensing of wetland features in arid landscapes.

Unraveling the complexity of iron oxides at high pressure and temperature: Synthesis of Fe 5O 6

DOE PAGES

Lavina, Barbara; Meng, Yue

2015-06-26

The iron-oxygen system is the most important reference of rocks’ redox state. Even as minor components, iron oxides can play a critical role in redox equilibria, which affect the speciation of the fluid phases chemical differentiation, melting, and physical properties. Until our recent finding of Fe 4O 5, iron oxides were assumed to comprise only the polymorphs of FeO, Fe 3O 4, and Fe 2O 3. Combining synthesis at high pressure and temperature with micro- diffraction mapping, we have identified yet another distinct iron oxide, Fe 5O 6. The new compound, which has an orthorhombic structure, was obtained in themore » pressure range from 10 to 20 GPa upon laser heating mixtures of iron and hematite at ~2000 K, and is recoverable to ambient conditions. The high-pressure orthorhombic iron oxides Fe 5O 6, Fe 4O 5, and h-Fe 3O 4 display similar iron coordination geometries and structural arrangements, and indeed exhibit coherent systematic behavior of crystallographic parameters and compressibility. Fe 5O 6, along with FeO and Fe 4O 5, is a candidate key minor phase of planetary interiors; as such, it is of major petrological and geo- chemical importance. Here, we are revealing an unforeseen complexity in the Fe-O system with four different compounds—FeO, Fe 5O 6, Fe 4O 5, and h-Fe 3O 4—in a narrow compositional range (0.75 < Fe/O < 1.0). New, finely spaced oxygen buffers at conditions of the Earth’s mantle can be defined.« less

High Precision Pressure Measurement with a Funnel

ERIC Educational Resources Information Center

Lopez-Arias, T.; Gratton, L. M.; Oss, S.

2008-01-01

A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

Sex-specific associations between cerebrovascular blood pressure autoregulation and cardiopulmonary injury in neonatal encephalopathy and therapeutic hypothermia

PubMed Central

Chavez-Valdez, Raul; O’Connor, Matthew; Perin, Jamie; Reyes, Michael; Armstrong, Jillian; Parkinson, Charlamaine; Gilmore, Maureen; Jennings, Jacky; Northington, Frances J.; Lee, Jennifer K.

2017-01-01

Background Cardiopulmonary injury is common in neonatal encephalopathy, but the link with cerebrovascular dysfunction is unknown. We hypothesized that cerebral autoregulation is associated with cardiopulmonary injury in neonates treated with therapeutic hypothermia (TH) for neonatal encephalopathy. Methods The cerebral hemoglobin volume index (HVx) from near-infrared spectroscopy was used to identify the mean arterial blood pressure (MAP) with optimal autoregulatory vasoreactivity (MAPOPT). We measured associations between MAP relative to MAPOPT and indicators of cardiopulmonary injury (duration of mechanical respiratory support and administration of inhaled nitric oxide (iNO), milrinone, or steroids). Results We identified associations between cerebrovascular autoregulation and cardiopulmonary injury that were often sex-specific. Greater MAP deviation above MAPOPT was associated with shorter duration of intubation in boys but longer ventilatory support in girls. Greater MAP deviation below MAPOPT related to longer intensive care stay in boys. Milrinone was associated with greater MAP deviation below MAPOPT in girls. Conclusion MAP deviation from MAPOPT may relate to cardiopulmonary injury after neonatal encephalopathy, and sex may modulate this relationship. Whereas MAP above MAPOPT may protect the brain and lungs in boys, it may be related to cardiopulmonary injury in girls. Future studies are needed to characterize the role of sex in these associations. PMID:28141793

Function Clustering Self-Organization Maps (FCSOMs) for mining differentially expressed genes in Drosophila and its correlation with the growth medium.

PubMed

Liu, L L; Liu, M J; Ma, M

2015-09-28

The central task of this study was to mine the gene-to-medium relationship. Adequate knowledge of this relationship could potentially improve the accuracy of differentially expressed gene mining. One of the approaches to differentially expressed gene mining uses conventional clustering algorithms to identify the gene-to-medium relationship. Compared to conventional clustering algorithms, self-organization maps (SOMs) identify the nonlinear aspects of the gene-to-medium relationships by mapping the input space into another higher dimensional feature space. However, SOMs are not suitable for huge datasets consisting of millions of samples. Therefore, a new computational model, the Function Clustering Self-Organization Maps (FCSOMs), was developed. FCSOMs take advantage of the theory of granular computing as well as advanced statistical learning methodologies, and are built specifically for each information granule (a function cluster of genes), which are intelligently partitioned by the clustering algorithm provided by the DAVID_6.7 software platform. However, only the gene functions, and not their expression values, are considered in the fuzzy clustering algorithm of DAVID. Compared to the clustering algorithm of DAVID, these experimental results show a marked improvement in the accuracy of classification with the application of FCSOMs. FCSOMs can handle huge datasets and their complex classification problems, as each FCSOM (modeled for each function cluster) can be easily parallelized.

Transcriptome sequencing of Eucalyptus camaldulensis seedlings subjected to water stress reveals functional single nucleotide polymorphisms and genes under selection

PubMed Central

2012-01-01

Background Water stress limits plant survival and production in many parts of the world. Identification of genes and alleles responding to water stress conditions is important in breeding plants better adapted to drought. Currently there are no studies examining the transcriptome wide gene and allelic expression patterns under water stress conditions. We used RNA sequencing (RNA-seq) to identify the candidate genes and alleles and to explore the evolutionary signatures of selection. Results We studied the effect of water stress on gene expression in Eucalyptus camaldulensis seedlings derived from three natural populations. We used reference-guided transcriptome mapping to study gene expression. Several genes showed differential expression between control and stress conditions. Gene ontology (GO) enrichment tests revealed up-regulation of 140 stress-related gene categories and down-regulation of 35 metabolic and cell wall organisation gene categories. More than 190,000 single nucleotide polymorphisms (SNPs) were detected and 2737 of these showed differential allelic expression. Allelic expression of 52% of these variants was correlated with differential gene expression. Signatures of selection patterns were studied by estimating the proportion of nonsynonymous to synonymous substitution rates (Ka/Ks). The average Ka/Ks ratio among the 13,719 genes was 0.39 indicating that most of the genes are under purifying selection. Among the positively selected genes (Ka/Ks > 1.5) apoptosis and cell death categories were enriched. Of the 287 positively selected genes, ninety genes showed differential expression and 27 SNPs from 17 positively selected genes showed differential allelic expression between treatments. Conclusions Correlation of allelic expression of several SNPs with total gene expression indicates that these variants may be the cis-acting variants or in linkage disequilibrium with such variants. Enrichment of apoptosis and cell death gene categories among the positively selected genes reveals the past selection pressures experienced by the populations used in this study. PMID:22853646

Retrieving Ice Basal Motion Using the Hydrologically Coupled JPL/UCI Ice Sheet System Model (ISSM)

NASA Astrophysics Data System (ADS)

Khakbaz, B.; Morlighem, M.; Seroussi, H. L.; Larour, E. Y.

2011-12-01

The study of basal sliding in ice sheets requires coupling ice-flow models with subglacial water flow. In fact, subglacial hydrology models can be used to model basal water-pressure explicitly and to generate basal sliding velocities. This study addresses the addition of a thin-film-based subglacial hydrologic module to the Ice Sheet System Model (ISSM) developed by JPL in collaboration with the University of California Irvine (UCI). The subglacial hydrology model follows the study of J. Johnson (2002) who assumed a non-arborscent distributed drainage system in the form of a thin film beneath ice sheets. The differential equation that arises from conservation of mass in the water system is solved numerically with the finite element method in order to obtain the spatial distribution of basal water over the study domain. The resulting sheet water thickness is then used to model the basal water-pressure and subsequently the basal sliding velocity. In this study, an introduction and preliminary results of the subglacial water flow and basal sliding velocity will be presented for the Pine Island Glacier west Antarctica.This work was performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Modeling, Analysis and Prediction (MAP) Program.

The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate.

PubMed

Damkjaer, M; Wang, T; Brøndum, E; Østergaard, K H; Baandrup, U; Hørlyck, A; Hasenkam, J M; Smerup, M; Funder, J; Marcussen, N; Danielsen, C C; Bertelsen, M F; Grøndahl, C; Pedersen, M; Agger, P; Candy, G; Aalkjaer, C; Bie, P

2015-08-01

The tallest animal on earth, the giraffe (Giraffa camelopardalis) is endowed with a mean arterial blood pressure (MAP) twice that of other mammals. The kidneys reside at heart level and show no sign of hypertension-related damage. We hypothesized that a species-specific evolutionary adaption in the giraffe kidney allows normal for size renal haemodynamics and glomerular filtration rate (GFR) despite a MAP double that of other mammals. Fourteen anaesthetized giraffes were instrumented with vascular and bladder catheters to measure glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Renal interstitial hydrostatic pressure (RIHP) was assessed by inserting a needle into the medullary parenchyma. Doppler ultrasound measurements provided renal artery resistive index (RI). Hormone concentrations as well as biomechanical, structural and histological characteristics of vascular and renal tissues were determined. GFR averaged 342 ± 99 mL min(-1) and ERPF 1252 ± 305 mL min(-1) . RIHP varied between 45 and 140 mmHg. Renal pelvic pressure was 39 ± 2 mmHg and renal venous pressure 32 ± 4 mmHg. A valve-like structure at the junction of the renal and vena cava generated a pressure drop of 12 ± 2 mmHg. RI was 0.27. The renal capsule was durable with a calculated burst pressure of 600 mmHg. Plasma renin and AngII were 2.6 ± 0.5 mIU L(-1) and 9.1 ± 1.5 pg mL(-1) respectively. In giraffes, GFR, ERPF and RI appear much lower than expected based on body mass. A strong renal capsule supports a RIHP, which is >10-fold that of other mammals effectively reducing the net filtration pressure and protecting against the high MAP. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Aortic-Brachial Pulse Wave Velocity Ratio: A Measure of Arterial Stiffness Gradient Not Affected by Mean Arterial Pressure.

PubMed

Fortier, Catherine; Desjardins, Marie-Pier; Agharazii, Mohsen

2018-03-01

Aortic stiffness, measured by carotid-femoral pulse wave velocity (cf-PWV), is used for the prediction of cardiovascular risk. This mini-review describes the nonlinear relationship between cf-PWV and operational blood pressure, presents the proposed methods to adjust for this relationship, and discusses a potential place for aortic-brachial PWV ratio (a measure of arterial stiffness gradient) as a blood pressure-independent measure of vascular aging. PWV is inherently dependent on the operational blood pressure. In cross-sectional studies, PWV adjustment for mean arterial pressure (MAP) is preferred, but still remains a nonoptimal approach, as the relationship between PWV and blood pressure is nonlinear and varies considerably among individuals due to heterogeneity in genetic background, vascular tone, and vascular remodeling. Extrapolations from the blood pressure-independent stiffness parameter β (β 0 ) have led to the creation of stiffness index β, which can be used for local stiffness. A similar approach has been used for cardio-ankle PWV to generate a blood pressure-independent cardio-ankle vascular index (CAVI). It was recently demonstrated that stiffness index β and CAVI remain slightly blood pressure-dependent, and a more appropriate formula has been proposed to make the proper adjustments. On the other hand, the negative impact of aortic stiffness on clinical outcomes is thought to be mediated through attenuation or reversal of the arterial stiffness gradient, which can also be influenced by a reduction in peripheral medium-sized muscular arteries in conditions that predispose to accelerate vascular aging. Arterial stiffness gradient, assessed by aortic-brachial PWV ratio, is emerging to be at least as good as cf-PWV for risk prediction, but has the advantage of not being affected by operating MAP. The negative impacts of aortic stiffness on clinical outcomes are proposed to be mediated through attenuation or reversal of arterial stiffness gradient. Aortic-brachial PWV ratio, a measure of arterial stiffness gradient, is independent of MAP.

Dynamic Hydrostatic Pressure Promotes Differentiation of Human Dental Pulp Stem Cells

PubMed Central

Yu, V; Damek-Poprawa, M.; Nicoll, S. B.; Akintoye, S.O.

2009-01-01

The masticatory apparatus absorbs high occlusal forces, but uncontrolled parafunctional or orthodontic forces damage periodontal ligament (PDL), cause pulpal calcification, pulp necrosis and tooth loss. Morphology and functional differentiation of connective tissue cells can be controlled by mechanical stimuli but effects of uncontrolled forces on intra-pulpal homeostasis and ability of dental pulp stem cells (DPSCs) to withstand direct external forces are unclear. Using dynamic hydrostatic pressure (HSP), we tested the hypothesis that direct HSP disrupts DPSC survival and odontogenic differentiation. DPSCs from four teenage patients were subjected to HSP followed by assessment of cell adhesion, survival and recovery capacity based on odontogenic differentiation, mineralization and responsiveness to bone morphogenetic protein-2 (BMP-2). HSP down-regulated DPSC adhesion and survival but promoted differentiation by increasing mineralization, in vivo hard tissue regeneration and BMP-2 responsiveness despite reduced cell numbers. HSP-treated DPSCs displayed enhanced odontogenic differentiation, an indication of favorable recovery from HSP-induced cellular stress. PMID:19555657

Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

NASA Astrophysics Data System (ADS)

Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

2016-06-01

Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

Earthquake dynamics. Mapping pressurized volcanic fluids from induced crustal seismic velocity drops.

PubMed

Brenguier, F; Campillo, M; Takeda, T; Aoki, Y; Shapiro, N M; Briand, X; Emoto, K; Miyake, H

2014-07-04

Volcanic eruptions are caused by the release of pressure that has accumulated due to hot volcanic fluids at depth. Here, we show that the extent of the regions affected by pressurized fluids can be imaged through the measurement of their response to transient stress perturbations. We used records of seismic noise from the Japanese Hi-net seismic network to measure the crustal seismic velocity changes below volcanic regions caused by the 2011 moment magnitude (M(w)) 9.0 Tohoku-Oki earthquake. We interpret coseismic crustal seismic velocity reductions as related to the mechanical weakening of the pressurized crust by the dynamic stress associated with the seismic waves. We suggest, therefore, that mapping seismic velocity susceptibility to dynamic stress perturbations can be used for the imaging and characterization of volcanic systems. Copyright © 2014, American Association for the Advancement of Science.

Agreement between invasive blood pressures measured in three peripheral arteries in anaesthetized horses under clinical conditions.

PubMed

Wilson, Keely A T; Raisis, Anthea L; Drynan, Eleanor A; Lester, Guy D; Hosgood, Giselle L

2018-05-01

To determine agreement between invasive blood pressures measured in three peripheral arteries in anaesthetized horses undergoing elective surgery. Prospective balanced incomplete block design. A total of 18 client-owned horses. Invasive blood pressure (IBP) was measured simultaneously in one of the following three combinations: 1) transverse facial and facial artery; 2) transverse facial and metatarsal artery; and 3) facial and metatarsal artery. The agreement in blood pressure measured for each combination was performed in six horses. At each sample time, systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were measured concurrently in each artery, and the mean of three consecutive measurements was recorded. The position of horse, heart rate and use of dobutamine were also recorded. Bland-Altman analysis was used to assess agreement between sites. A total of 54 paired measurements were obtained, with 18 paired measurements from each combination. All paired measurements showed poor and haphazard (nonsystematic) agreement. The widest limit of agreement was 51 mmHg for SAP measured in the facial artery and metatarsal artery, with a bias of -11 mmHg. The smallest limit of agreement was 16 mmHg for MAP measured in the transverse facial and metatarsal artery, with a bias of 1 mmHg. There was poor and haphazard agreement for SAP, MAP and DAP measured in each pair of peripheral arteries in this study. These results show that blood pressure measured in different peripheral arteries cannot be used interchangeably. This has implications for studies that use IBP as an outcome variable and studies determining agreement between noninvasive blood pressure and IBP measurements in horses under general anaesthesia. Copyright © 2018 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.

A linear shock cell model for non-circular jets using conformal mapping with a pseudo-spectral hybrid scheme

NASA Technical Reports Server (NTRS)

Bhat, Thonse R. S.; Baty, Roy S.; Morris, Philip J.

1990-01-01

The shock structure in non-circular supersonic jets is predicted using a linear model. This model includes the effects of the finite thickness of the mixing layer and the turbulence in the jet shear layer. A numerical solution is obtained using a conformal mapping grid generation scheme with a hybrid pseudo-spectral discretization method. The uniform pressure perturbation at the jet exit is approximated by a Fourier-Mathieu series. The pressure at downstream locations is obtained from an eigenfunction expansion that is matched to the pressure perturbation at the jet exit. Results are presented for a circular jet and for an elliptic jet of aspect ratio 2.0. Comparisons are made with experimental data.

Comparison of directly measured arterial blood pressure at various anatomic locations in anesthetized dogs.

PubMed

Acierno, Mark J; Domingues, Michelle E; Ramos, Sara J; Shelby, Amanda M; da Cunha, Anderson F

2015-03-01

To determine whether directly measured arterial blood pressure differs among anatomic locations and whether arterial blood pressure is influenced by body position. 33 client-owned dogs undergoing anesthesia. Dogs undergoing anesthetic procedures had 20-gauge catheters placed in both the superficial palmar arch and the contralateral dorsal pedal artery (group 1 [n = 20]) or the superficial palmar arch and median sacral artery (group 2 [13]). Dogs were positioned in dorsal recumbency, and mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), and diastolic arterial blood pressure (DAP) were recorded for both arteries 4 times (2-minute interval between successive measurements). Dogs were positioned in right lateral recumbency, and blood pressure measurements were repeated. Differences were detected between pressures measured at the 2 arterial sites in both groups. This was especially true for SAP measurements in group 1, in which hind limb measurements were a mean of 16.12 mm Hg higher than carpus measurements when dogs were in dorsal recumbency and 14.70 mm Hg higher than carpus measurements when dogs were in lateral recumbency. Also, there was significant dispersion about the mean for all SAP, DAP, and MAP measurements. Results suggested that arterial blood pressures may be dependent on anatomic location and body position. Because this may affect outcomes of studies conducted to validate indirect blood pressure measurement systems, care must be used when developing future studies or interpreting previous results.

Fusion of Location Fingerprinting and Trilateration Based on the Example of Differential Wi-Fi Positioning

NASA Astrophysics Data System (ADS)

Retscher, G.

2017-09-01

Positioning of mobile users in indoor environments with Wireless Fidelity (Wi-Fi) has become very popular whereby location fingerprinting and trilateration are the most commonly employed methods. In both the received signal strength (RSS) of the surrounding access points (APs) are scanned and used to estimate the user's position. Within the scope of this study the advantageous qualities of both methods are identified and selected to benefit their combination. By a fusion of these technologies a higher performance for Wi-Fi positioning is achievable. For that purpose, a novel approach based on the well-known Differential GPS (DGPS) principle of operation is developed and applied. This approach for user localization and tracking is termed Differential Wi-Fi (DWi-Fi) by analogy with DGPS. From reference stations deployed in the area of interest differential measurement corrections are derived and applied at the mobile user side. Hence, range or coordinate corrections can be estimated from a network of reference station observations as it is done in common CORS GNSS networks. A low-cost realization with Raspberry Pi units is employed for these reference stations. These units serve at the same time as APs broadcasting Wi-Fi signals as well as reference stations scanning the receivable Wi-Fi signals of the surrounding APs. As the RSS measurements are carried out continuously at the reference stations dynamically changing maps of RSS distributions, so-called radio maps, are derived. Similar as in location fingerprinting this radio maps represent the RSS fingerprints at certain locations. From the areal modelling of the correction parameters in combination with the dynamically updated radio maps the location of the user can be estimated in real-time. The novel approach is presented and its performance demonstrated in this paper.

Land use mapping in Erie County, Pennsylvania: A pilot study

NASA Technical Reports Server (NTRS)

Mcmurtry, G. J.; Petersen, G. W. (Principal Investigator); May, G. A.

1974-01-01

The author has identified the following significant results. A pilot study was conducted to determine the feasibility of mapping land use in the Great Lakes Basin area utilizing ERTS-1 data. Small streams were clearly defined by the presence of trees along their length in predominantly agricultural country. Field patterns were easily differentiated from forested areas; dairy and beef farms were differentiated from other farmlands, but no attempt was made to identify crops. Large railroad lines and major highway systems were identified. The city of Erie and several smaller towns were identified, as well as residential areas between these towns, and docks along the shoreline in Erie. Marshes, forests, and beaches within Presque Isle State Park were correctly identified, using the DCLUS program. Bay water was differentiated from lake water, with a small amount of misclassification.

The differential path phase comparison method for determining pressure derivatives of elastic constants of solids

NASA Astrophysics Data System (ADS)

Peselnick, L.

1982-08-01

An ultrasonic method is presented which combines features of the differential path and the phase comparison methods. The proposed differential path phase comparison method, referred to as the `hybrid' method for brevity, eliminates errors resulting from phase changes in the bond between the sample and buffer rod. Define r(P) [and R(P)] as the square of the normalized frequency for cancellation of sample waves for shear [and for compressional] waves. Define N as the number of wavelengths in twice the sample length. The pressure derivatives r'(P) and R' (P) for samples of Alcoa 2024-T4 aluminum were obtained by using the phase comparison and the hybrid methods. The values of the pressure derivatives obtained by using the phase comparison method show variations by as much as 40% for small values of N (N < 50). The pressure derivatives as determined from the hybrid method are reproducible to within ±2% independent of N. The values of the pressure derivatives determined by the phase comparison method for large N are the same as those determined by the hybrid method. Advantages of the hybrid method are (1) no pressure dependent phase shift at the buffer-sample interface, (2) elimination of deviatoric stress in the sample portion of the sample assembly with application of hydrostatic pressure, and (3) operation at lower ultrasonic frequencies (for comparable sample lengths), which eliminates detrimental high frequency ultrasonic problems. A reduction of the uncertainties of the pressure derivatives of single crystals and of low porosity polycrystals permits extrapolation of such experimental data to deeper mantle depths.

Comparison of magnetic resonance elastography and diffusion-weighted imaging for differentiating benign and malignant liver lesions.

PubMed

Hennedige, Tiffany P; Hallinan, James Thomas Patrick Decourcy; Leung, Fiona P; Teo, Lynette Li San; Iyer, Sridhar; Wang, Gang; Chang, Stephen; Madhavan, Krishna Kumar; Wee, Aileen; Venkatesh, Sudhakar K

2016-02-01

Comparison of magnetic resonance elastography (MRE) and diffusion-weighted imaging (DWI) for differentiating malignant and benign focal liver lesions (FLLs). Seventy-nine subjects with 124 FLLs (44 benign and 80 malignant) underwent both MRE and DWI. MRE was performed with a modified gradient-echo sequence and DWI with a free breathing technique (b = 0.500). Apparent diffusion coefficient (ADC) maps and stiffness maps were generated. FLL mean stiffness and ADC values were obtained by placing regions of interest over the FLLs on stiffness and ADC maps. The accuracy of MRE and DWI for differentiation of benign and malignant FLL was compared using receiver operating curve (ROC) analysis. There was a significant negative correlation between stiffness and ADC (r = -0.54, p < 0.0001) of FLLs. Malignant FLLs had significantly higher mean stiffness (7.9kPa vs. 3.1kPa, p < 0.001) and lower mean ADC (129 vs. 200 × 10(-3)mm(2)/s, p < 0.001) than benign FLLs. The sensitivity/specificity/positive predictive value/negative predictive value for differentiating malignant from benign FLLs with MRE (cut-off, >4.54kPa) and DWI (cut-off, <151 × 10(-3)mm(2)/s) were 96.3/95.5/97.5/93.3% (p < 0.001) and 85/81.8/88.3/75% (p < 0.001), respectively. ROC analysis showed significantly higher accuracy for MRE than DWI (0.986 vs. 0.82, p = 0.0016). MRE is significantly more accurate than DWI for differentiating benign and malignant FLLs. • MRE is superior to DWI for differentiating benign and malignant focal liver lesions. • Benign lesions with large fibrous components may have higher stiffness with MRE. • Cholangiocarcinomas tend to have higher stiffness than hepatocellular carcinomas. • Hepatocellular adenomas tend to have lower stiffness than focal nodular hyperplasia. • MRE is superior to conventional MRI in differentiating benign and malignant liver lesions.

Fluidic angular velocity sensor

NASA Technical Reports Server (NTRS)

Berdahl, C. M. (Inventor)

1986-01-01

A fluidic sensor providing a differential pressure signal proportional to the angular velocity of a rotary input is described. In one embodiment the sensor includes a fluid pump having an impeller coupled to a rotary input. A housing forming a constricting fluid flow chamber is connected to the fluid input of the pump. The housing is provided with a fluid flow restrictive input to the flow chamber and a port communicating with the interior of the flow chamber. The differential pressure signal measured across the flow restrictive input is relatively noise free and proportional to the square of the angular velocity of the impeller. In an alternative embodiment, the flow chamber has a generally cylindrical configuration and plates having flow restrictive apertures are disposed within the chamber downstream from the housing port. In this embodiment, the differential pressure signal is found to be approximately linear with the angular velocity of the impeller.

Method for automatically scramming a nuclear reactor

DOEpatents

Ougouag, Abderrafi M.; Schultz, Richard R.; Terry, William K.

2005-12-27

An automatically scramming nuclear reactor system. One embodiment comprises a core having a coolant inlet end and a coolant outlet end. A cooling system operatively associated with the core provides coolant to the coolant inlet end and removes heated coolant from the coolant outlet end, thus maintaining a pressure differential therebetween during a normal operating condition of the nuclear reactor system. A guide tube is positioned within the core with a first end of the guide tube in fluid communication with the coolant inlet end of the core, and a second end of the guide tube in fluid communication with the coolant outlet end of the core. A control element is positioned within the guide tube and is movable therein between upper and lower positions, and automatically falls under the action of gravity to the lower position when the pressure differential drops below a safe pressure differential.

Calcium ion propagation in cultured keratinocytes and other cells in skin in response to hydraulic pressure stimulation.

PubMed

Goto, Makiko; Ikeyama, Kazuyuki; Tsutsumi, Moe; Denda, Sumiko; Denda, Mitsuhiro

2010-07-01

We have previously suggested that a variety of environmental factors might be first sensed by epidermal keratinocytes, which represent the frontier of the body. To further examine this idea, in the present study, we examined the intracellular calcium responses of cultured keratinocytes to external hydraulic pressure. First, we compared the responses of undifferentiated and differentiated keratinocytes with those of fibroblasts, vascular endothelial cells (VEC), and lymphatic endothelial cells. Elevation of intracellular calcium was observed after application of pressure to keratinocytes, fibroblasts, and VEC. The calcium propagation extended over a larger area and continued for a longer period of time in differentiated keratinocytes, as compared with the other cells. The response of the keratinocytes was dramatically reduced when the cells were incubated in medium without calcium. Application of a non-selective transient receptor potential (TRP) channel blocker also attenuated the calcium response. These results suggest that differentiated keratinocytes are sensitive to external pressure and that TRP might be involved in the mechanism of their response. (c) 2010 Wiley-Liss, Inc.

Analytic Formulation and Numerical Implementation of an Acoustic Pressure Gradient Prediction

NASA Technical Reports Server (NTRS)

Lee, Seongkyu; Brentner, Kenneth S.; Farassat, F.; Morris, Philip J.

2008-01-01

Two new analytical formulations of the acoustic pressure gradient have been developed and implemented in the PSU-WOPWOP rotor noise prediction code. The pressure gradient can be used to solve the boundary condition for scattering problems and it is a key aspect to solve acoustic scattering problems. The first formulation is derived from the gradient of the Ffowcs Williams-Hawkings (FW-H) equation. This formulation has a form involving the observer time differentiation outside the integrals. In the second formulation, the time differentiation is taken inside the integrals analytically. This formulation avoids the numerical time differentiation with respect to the observer time, which is computationally more efficient. The acoustic pressure gradient predicted by these new formulations is validated through comparison with available exact solutions for a stationary and moving monopole sources. The agreement between the predictions and exact solutions is excellent. The formulations are applied to the rotor noise problems for two model rotors. A purely numerical approach is compared with the analytical formulations. The agreement between the analytical formulations and the numerical method is excellent for both stationary and moving observer cases.

Pressure overload differentially affects respiratory capacity in interfibrillar and subsarcolemmal mitochondria.

PubMed

Schwarzer, Michael; Schrepper, Andrea; Amorim, Paulo A; Osterholt, Moritz; Doenst, Torsten

2013-02-15

Years ago a debate arose as to whether two functionally different mitochondrial subpopulations, subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM), exist in heart muscle. Nowadays potential differences are often ignored. Presumably, SSM are providing ATP for basic cell function, whereas IFM provide energy for the contractile apparatus. We speculated that two distinguishable subpopulations exist that are differentially affected by pressure overload. Male Sprague-Dawley rats were subjected to transverse aortic constriction for 20 wk or sham operation. Contractile function was assessed by echocardiography. Heart tissue was analyzed by electron microscopy. Mitochondria were isolated by differential centrifugation, and respiratory capacity was analyzed using a Clark electrode. Pressure overload induced left ventricular hypertrophy with increased posterior wall diameter and impaired contractile function. Mitochondrial state 3 respiration in control was 50% higher in IFM than in SSM. Pressure overload significantly impaired respiratory rates in both IFM and SSM, but in SSM to a lower extent. As a result, there were no differences between SSM and IFM after 20 wk of pressure overload. Pressure overload reduced total citrate synthase activity, suggesting reduced total mitochondrial content. Electron microscopy revealed normal morphology of mitochondria but reduced total mitochondrial volume density. In conclusion, IFM show greater respiratory capacity in the healthy rat heart and a greater depression of respiratory capacity by pressure overload than SSM. The differences in respiratory capacity of cardiac IFM and SSM in healthy hearts are eliminated with pressure overload-induced heart failure. The strong effect of pressure overload on IFM together with the simultaneous appearance of mitochondrial and contractile dysfunction may support the notion of IFM primarily producing ATP for contractile function.

Role of Re-entry Tears on the Dynamics of Type B Dissection Flap.

PubMed

Canchi, Saranya; Guo, Xiaomei; Phillips, Matt; Berwick, Zachary; Kratzberg, Jarin; Krieger, Joshua; Roeder, Blayne; Haulon, Stephan; Chambers, Sean; Kassab, Ghassan S

2018-01-01

Mortality during follow-up after acute Type B aortic dissection is substantial with aortic expansion observed in over 59% of the patients. Lumen pressure differential is considered a prime contributing factor for aortic dilation after propagation. The objective of the study was to evaluate the relationship between changes in vessel geometry with and without lumen pressure differential post propagation in an ex vivo porcine model with comparison with patient clinical data. A pulse duplicator system was utilized to propagate the dissection within descending thoracic porcine aortic vessels for set proximal (%circumference of the entry tear: 40%, axial length: 2 cm) and re-entry (50% of distal vessel circumference) tear geometry. Measurements of lumen pressure differential were made along with quantification of vessel geometry (n = 16). The magnitude of mean lumen pressure difference measured after propagation was low (~ 5 mmHg) with higher pressures measured in false lumen and as anticipated the pressure difference approached zero after the creation of distal re-entry tear. False lumen Dissection Ratio (FDR) defined as arc length of dissected wall divided by arc length of dissection flap, had mean value of 1.59 ± 0.01 at pressure of 120/80 mmHg post propagation with increasing values with increase in pulse pressure that was not rescued with the creation of distal re-entry tear (p < 0.01). An average FDR of 1.87 ± 0.27 was measured in patients with acute Type B dissection. Higher FDR value (FDR = 1 implies zero dissection) in the presence of distal re-entry tear demonstrates an acute change in vessel morphology in response to the dissection independent of local pressure changes challenges the re-apposition of the aortic wall.

The Hemodynamic Changes in Patients with Cerebral Arteriovenous Malformations before and after Interventional Embolization Therapy with Glubran 2 Acrylic Glue.

PubMed

Chen, Qi-Yu; Zhu, Xiao-Rui; Zhang, Yu

2017-01-01

The study explored hemodynamic changes in patients with cerebral arteriovenous malformations (CAVM) before and -after interventional embolization therapy with Glubran 2 acrylic glue and analyzed the related factors. CAVM patients received endovascular embolization therapy with Glubran 2. Patients' systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), blood flow velocity (BFV), and pulsatility index (PI) were measured. The location of malformed vessels, Spetzler-Martin (SM) grade, CAVM size, and type of feeding artery and venous drainage were analyzed. CAVM patients showed increased DBP, SBP, MAP, and PI and decreased average BFV compared to before therapy. CAVM patients with big CAVM size, SM grade IV/V, deep location malformed vessels, deep, and mixed venous drainage, and cortical branch and mixed artery blood-supply exhibited lower DBP, SBP, MAP, and PI but higher average BFV. Hypertensive CAVM patients showed lower DBP, SBP, MAP, average BFV, and PI before or after embolization. Hypertension, SM grade, CAVM size, malformed vessels location, venous drainage, and artery blood-supply were correlated to the hemodynamic changes of CAVM patients. Embolization with Glubran 2 acrylic glue could enhance hemodynamics in CAVM patients, and the hemodynamic changes were in correlation with the SM grade, CAVM size, and malformed vessels location. © 2017 S. Karger AG, Basel.

Inhibition of KATP channel activity augments baroreflex-mediated vasoconstriction in exercising human skeletal muscle

PubMed Central

Keller, David Melvin; Ogoh, Shigehiko; Greene, Shane; Olivencia-Yurvati, A; Raven, Peter B

2004-01-01

In the present investigation we examined the role of ATP-sensitive potassium (KATP) channel activity in modulating carotid baroreflex (CBR)-induced vasoconstriction in the vasculature of the leg. The CBR control of mean arterial pressure (MAP) and leg vascular conductance (LVC) was determined in seven subjects (25 ± 1 years, mean ± s.e.m.) using the variable-pressure neck collar technique at rest and during one-legged knee extension exercise. The oral ingestion of glyburide (5 mg) did not change mean arterial pressure (MAP) at rest (86 versus 89 mmHg, P > 0.05), but did appear to increase MAP during exercise (87 versus 92 mmHg, P = 0.053). However, the CBR–MAP function curves were similar at rest before and after glyburide ingestion. The CBR-mediated decrease in LVC observed at rest (∼39%) was attenuated during exercise in the exercising leg (∼15%, P < 0.05). Oral glyburide ingestion partially restored CBR-mediated vasoconstriction in the exercising leg (∼40% restoration, P < 0.05) compared to control exercise. These findings indicate that KATP channel activity modulates sympathetic vasoconstriction in humans and may prove to be an important mechanism by which functional sympatholysis operates in humans during exercise. PMID:15345750

Effect of celecoxib on the antihypertensive effect of losartan in a rat model of renovascular hypertension.

PubMed

Boshra, Vivian; El Wakeel, Gehan Abdel Hamid; Nader, Manar A

2011-02-01

Certain nonsteroidal anti-inflammatory drugs have been reported to elevate blood pressure in some hypertensive patients, who are either untreated or treated with antihypertensive agents. This study was undertaken to determine the effect of a selective cyclooxygenase-2 (COX-2) inhibitor, celecoxib, on the antihypertensive effects of the angiotensin II type 1 receptor (AT1) antagonist, losartan potassium. We studied the effect of oral treatment with losartan (30 mg/kg), celecoxib (3 mg/kg), and their combination on the mean arterial blood pressure (MAP), plasma renin activity (PRA), and plasma prostaglandin E2 (PGE2) in male Sprague-Dawley rats with renovascular hypertension (RVH) induced by partial subdiaphragmatic aortic constriction. Treatment was continued for 7 days after aortic coarctation. Aortic coarctation led to significant increases in the MAP, PRA, and plasma PGE2. In RVH rats, losartan treatment caused a significant decrease of MAP with a significant increase in both plasma PGE2 and PRA. Celecoxib caused a nonsignificant change in MAP with a significant decrease in the raised levels of plasma PGE2 and PRA. Concomitant administration of celecoxib and losartan did not significantly affect the lowering effect of losartan on MAP with a subsequent significant decrease in the plasma PGE2 and PRA in RVH rats. Therefore, celecoxib could be used in renin-dependent hypertensive patients who receive losartan, without fear of a rise in their blood pressure.

Pressure suppression containment system for boiling water reactor

DOEpatents

Gluntz, Douglas M.; Nesbitt, Loyd B.

1997-01-01

A system for suppressing the pressure inside the containment of a BWR following a postulated accident. A piping subsystem is provided which features a main process pipe that communicates the wetwell airspace to a connection point downstream of the guard charcoal bed in an offgas system and upstream of the main bank of delay charcoal beds which give extensive holdup to offgases. The main process pipe is fitted with both inboard and outboard containment isolation valves. Also incorporated in the main process pipe is a low-differential-pressure rupture disk which prevents any gas outflow in this piping whatsoever until or unless rupture occurs by virtue of pressure inside this main process pipe on the wetwell airspace side of the disk exceeding the design opening (rupture) pressure differential. The charcoal holds up the radioactive species in the noncondensable gas from the wetwell plenum by adsorption, allowing time for radioactive decay before the gas is vented to the environs.

Thermal and structural alternations in CuAlMnNi shape memory alloy by the effect of different pressure applications

NASA Astrophysics Data System (ADS)

Canbay, Canan Aksu; Polat, Tercan

2017-09-01

In this work the effects of the applied pressure on the characteristic transformation temperatures, the high temperature order-disorder phase transitions, the variation in diffraction peaks and the surface morphology of the CuAlMnNi shape memory alloy was investigated. The evolution of the transformation temperatures was studied by differential scanning calorimetry (DSC) with different heating and cooling rates. The differential thermal analysis measurements were performed to obtain the ordered-disordered phase transformations from room temperature to 900 °C. The characteristic transformation temperatures and the thermodynamic parameters were highly sensitive to variations in the applied pressure and also the applied pressure affected the thermodynamic parameters. The activation energy of the sample according to applied pressure values calculated by Kissinger method. The structural changes of the samples were studied by X-ray diffraction (XRD) measurements and by optical microscope observations at room temperature.

Apparatus and process to eliminate diffusional limitations in a membrane biological reactor by pressure cycling

DOEpatents

Efthymiou, George S.; Shuler, Michael L.

1989-08-29

An improved multilayer continuous biological membrane reactor and a process to eliminate diffusional limitations in membrane reactors in achieved by causing a convective flux of nutrient to move into and out of an immobilized biocatalyst cell layer. In a pressure cycled mode, by increasing and decreasing the pressure in the respective layers, the differential pressure between the gaseous layer and the nutrient layer is alternately changed from positive to negative. The intermittent change in pressure differential accelerates the transfer of nutrient from the nutrient layers to the biocatalyst cell layer, the transfer of product from the cell layer to the nutrient layer and the transfer of byproduct gas from the cell layer to the gaseous layer. Such intermittent cycling substantially eliminates mass transfer gradients in diffusion inhibited systems and greatly increases product yield and throughput in both inhibited and noninhibited systems.

Differential absorption lidar measurements of atmospheric temperature and pressure profiles

NASA Technical Reports Server (NTRS)

Korb, C. L.

1981-01-01

The theory and methodology of using differential absorption lidar techniques for the remote measurement of atmospheric pressure profiles, surface pressure, and temperature profiles from ground, air, and space-based platforms are presented. Pressure measurements are effected by means of high resolution measurement of absorption at the edges of the oxygen A band lines where absorption is pressure dependent due to collisional line broadening. Temperature is assessed using measurements of the absorption at the center of the oxygen A band line originating from a quantum state with high ground state energy. The population of the state is temperature dependent, allowing determination of the temperature through the Boltzmann term. The results of simulations of the techniques using Voigt profile and variational analysis are reported for ground-based, airborne, and Shuttle-based systems. Accuracies in the 0.5-1.0 K and 0.1-0.3% range are projected.

Safety Analysis LOX-30 Liquid Oxygen Generator.

DTIC Science & Technology

1978-05-22

Valve. Protects the LOX—30 plant against over—pressurization. Valve opens at approximately 100 psig. (3) Oil Pressure Switch . Protects compressor...29 psig. d. Cryogenerator. •0 (1) 011 Pressure Switch . Prevents cryogenerator damage due to inadequate lubrication. The switch initiates system shut...when helium pressure is less than 200 psig, will result in compressor shut—down within ten seconds. (2) Differential Pressure Switch (2 each). These

Research and Development of Advanced Life Support Equipment.

DTIC Science & Technology

1999-02-01

kg.) were catheterized f or measurement of left ventricular pressure (LVP), right ventricular pressure (RVP), mean aortic pressure (MAP), central ...Orientation Laboratory Venous Gas Emboli Variable Profile Breathing Simulator Wingate Anaerobic Test Weapons System Trainer World Wide Web... history screening of the potential subjects was conducted to eliminate those individuals who have known health conditions/ histories which would

Determination of the heat of hydride formation/decomposition by high-pressure differential scanning calorimetry (HP-DSC).

PubMed

Rongeat, Carine; Llamas-Jansa, Isabel; Doppiu, Stefania; Deledda, Stefano; Borgschulte, Andreas; Schultz, Ludwig; Gutfleisch, Oliver

2007-11-22

Among the thermodynamic properties of novel materials for solid-state hydrogen storage, the heat of formation/decomposition of hydrides is the most important parameter to evaluate the stability of the compound and its temperature and pressure of operation. In this work, the desorption and absorption behaviors of three different classes of hydrides are investigated under different hydrogen pressures using high-pressure differential scanning calorimetry (HP-DSC). The HP-DSC technique is used to estimate the equilibrium pressures as a function of temperature, from which the heat of formation is derived. The relevance of this procedure is demonstrated for (i) magnesium-based compounds (Ni-doped MgH2), (ii) Mg-Co-based ternary hydrides (Mg-CoHx) and (iii) Alanate complex hydrides (Ti-doped NaAlH4). From these results, it can be concluded that HP-DSC is a powerful tool to obtain a good approximation of the thermodynamic properties of hydride compounds by a simple and fast study of desorption and absorption properties under different pressures.

Macrophage differentiation increases expression of the ascorbate transporter (SVCT2)

PubMed Central

Qiao, Huan; May, James M.

2013-01-01

To determine whether macrophage differentiation involves increased uptake of vitamin C, or ascorbic acid, we assessed the expression and function of its transporter SVCT2 during phorbol ester-induced differentiation of human-derived THP-1 monocytes. Induction of THP-1 monocyte differentiation by phorbol 12-myristate 13-acetate (PMA) markedly increased SVCT2 mRNA, protein, and function. When ascorbate was present during PMA-induced differentiation, the increase in SVCT2 protein expression was inhibited, but differentiation was enhanced. PMA-induced SVCT2 protein expression was blocked by inhibitors of protein kinase C (PKC), with most of the affect due to the PKCβI and βII isoforms. Activation of MEK/ERK was sustained up to 48 h after PMA treatment, and the inhibitors completely blocked PMA-stimulated SVCT2 protein expression, indicating an exclusive role for the classical MAP kinase pathway. However, inhibitors of NF-κB activation, NADPH oxidase inhibitors, and several antioxidants also partially prevented SVCT2 induction, suggesting diverse distal routes for control of SVCT2 transcription. Both known promoters for the SVCT2 were involved in these effects. In conclusion, PMA-induced monocyte-macrophage differentiation is enhanced by ascorbate and associated with increased expression and function of the SVCT2 protein through a pathway involving sustained activation of PKCβI/II, MAP kinase, NADPH oxidase, and NF-κB. PMID:19232538

Calcium: A novel and efficient inducer of differentiation of adipose-derived stem cells into neuron-like cells.

PubMed

Goudarzi, Farjam; Tayebinia, Heidar; Karimi, Jamshid; Habibitabar, Elahe; Khodadadi, Iraj

2018-06-05

This study comparatively investigated the effectiveness of calcium and other well-known inducers such as isobutylmethylxanthine (IBMX) and insulin in differentiating human adipose-derived stem cells (ADSCs) into neuronal-like cells. ADSCs were immunophenotyped and differentiated into neuron-like cells with different combinations of calcium, IBMX, and insulin. Calcium mobilization across the membrane was determined. Differentiated cells were characterized by cell cycle profiling, staining of Nissl bodies, detecting the gene expression level of markers such as neuronal nuclear antigen (NeuN), microtubule associated protein 2 (MAP2), neuron-specific enolase (NSE), doublecortin, synapsin I, glial fibrillary acidic protein (GFAP), and myelin basic protein (MBP) by quantitative real-time polymerase chain reaction (quantitative real-time polymerase chain reaction (qRT-PCR) and protein level by the immunofluorescence technique. Treatment with Ca + IBMX + Ins induced neuronal appearance and projection of neurite-like processes in the cells, accompanied with inhibition of proliferation and halt in the cell cycle. A significantly higher expression of MBP, GFAP, NeuN, NSE, synapsin 1, doublecortin, and MAP2 was detected in differentiated cells, confirming the advantages of Ca + IBMX + Ins to the other combinations of inducers. Here, we showed an efficient protocol for neuronal differentiation of ADSCs, and calcium fostered differentiation by augmenting the number of neuron-like cells and instantaneous increase in the expression of neuronal markers. © 2018 Wiley Periodicals, Inc.

Placental growth factor (PlGF) is a surrogate marker in preeclamptic hypertension.

PubMed

Teixeira, Patrícia Gonçalves; Cabral, Antônio Carlos Vieira; Andrade, Silvia Passos; Reis, Zilma Silveira Nogueira; da Cruz, Lívia Pieroni Barroso; Pereira, Jacqueline Braga; Martins, Breno Oliveira de Barcelos; Rezende, Cezar Alencar de Lima

2008-01-01

To evaluate plasma levels of angiogenic factors and their association with preeclampsia. Twenty-three women with preeclampsia and nine normotensive pregnant women from the Maternity of Hospital das Clínicas of Belo Horizonte/MG-Brazil were assessed by National High Blood Pressure Education Program Working Group Creteria (NHBPEPWG). The plasma levels of vascular endothelial growth factor (VEGF) and Placental growth factor (PlGF) were determined by ELISA assay. Plasma concentration of PlGF was 12-fold lower in preeclampsia versus non preeclampsia pregnancies. An inverse correlation was observed between PlGF plasma levels and mean arterial pressure (MAP); a decrease in 1pg/mL of PlGF resulted in 6.18 mm Hg increase in MAP. These results indicate that PlGF is related to MAP in pregnant women.

Analytical study of effect of casing treatment on performance of a multistage compressor

NASA Technical Reports Server (NTRS)

Snyder, R. W.; Blade, R. J.

1972-01-01

The simulation was based on individual stage pressure and efficiency maps. These maps were modified to account for casing treatment effects on the individual stage characteristics. The individual stage maps effects on overall compressor performance were observed. The results show that to improve the performance of the compressor in its normal operating range, casing treatment of the rear stages is required.

Oil field management system

DOEpatents

Fincke, James R.

2003-09-23

Oil field management systems and methods for managing operation of one or more wells producing a high void fraction multiphase flow. The system includes a differential pressure flow meter which samples pressure readings at various points of interest throughout the system and uses pressure differentials derived from the pressure readings to determine gas and liquid phase mass flow rates of the high void fraction multiphase flow. One or both of the gas and liquid phase mass flow rates are then compared with predetermined criteria. In the event such mass flow rates satisfy the predetermined criteria, a well control system implements a correlating adjustment action respecting the multiphase flow. In this way, various parameters regarding the high void fraction multiphase flow are used as control inputs to the well control system and thus facilitate management of well operations.

Alpha-adrenergic blocker mediated osteoblastic stem cell differentiation

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

Choi, Yoon Jung; Lee, Jue Yeon; Research Center, Nano Intelligent Biomedical Engineering Corporation

Highlights: Black-Right-Pointing-Pointer Doxazocin directly up-regulated bone metabolism at a low dose. Black-Right-Pointing-Pointer Doxazocin induced osteoblastic stem cell differentiation without affecting cell proliferation. Black-Right-Pointing-Pointer This osteogenic stem cell differentiation is mediated by ERK-signal dependent pathway. -- Abstract: Recent researches have indicated a role for antihypertensive drugs including alpha- or beta-blockers in the prevention of bone loss. Some epidemiological studies reported the protective effects of those agents on fracture risk. However, there is limited information on the association with those agents especially at the mechanism of action. In the present study, we investigated the effects of doxazosin, an alpha-blocker that is clinicallymore » used for the treatment of benign prostatic hyperplasia (BPH) along with antihypertensive medication, on the osteogenic stem cell differentiation. We found that doxazosin increased osteogenic differentiation of human mesenchymal stem cells, detected by Alizarin red S staining and calcein. Doxazosin not only induced expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin, it also resulted in increased phosphorylation of extracellular signal-regulated kinase (ERK1/2), a MAP kinase involved in osteoblastic differentiation. Treatment with U0126, a MAP kinase inhibitor, significantly blocked doxazosin-induced osteoblastic differentiation. Unrelated to activation of osteogenic differentiation by doxazosin, we found that there were no significant changes in adipogenic differentiation or in the expression of adipose-specific genes, including peroxisome proliferator-activated receptor {gamma}, aP2, or LPL. In this report, we suggest that doxazosin has the ability to increase osteogenic cell differentiation via ERK1/2 activation in osteogenic differentiation of adult stem cells, which supports the protective effects of antihypertensive drug on fracture risk and according to our data doxazosin might be useful for application in the field of bone metabolism.« less

Recent Developments Related To An Optically Controlled Microwave Phased Array Antenna.

NASA Astrophysics Data System (ADS)

Kittel, A.; Peinke, J.; Klein, M.; Baier, G.; Parisi, J.; Rössler, O. E.

1990-12-01

A generic 3-dimensional diffeomorphic map, with constant Jacobian determinant, is proposed and looked at numerically. It contains a lower-dimensional basin boundary along which a chaotic motion takes place. This boundary is nowhere differentiable in one direction. Therefore, nowhere differentiable limit sets exist generically in nature.

Acute effects of glossopharyngeal insufflation in people with cervical spinal cord injury.

PubMed

Nygren-Bonnier, Malin; Schiffer, Tomas A; Lindholm, Peter

2018-01-01

To evaluate acute effects of glossopharyngeal insufflation (GI) on lung function, airway pressure (P aw ), blood pressure and heart rate (HR) in people with cervical spinal cord injury (CSCI). Case-control design. Karolinska Institutet, Stockholm, Sweden. Ten participants with CSCI suffering from lesions between C4 and C8, and ASIA classification of A or B were recruited. Ten healthy particpants familiar with GI were recruited as a reference group. Spirometry, mean arterial blood pressure (MAP), P aw, and HR were measured in a sitting and a supine position before, during, and after GI. GI in the study group in a sitting position increased total lung capacity (TLC) by 712 ml: P < 0.001, vital capacity (VC) by 587 ml: P < 0.0001, P aw by 13 cm H 2 O: P < 0.01, and HR by 10 beats/min: P < 0.001. MAP decreased by 25 mmHg, P < 0.0001. Significant differences were observed between groups comparing baseline with GI. The reference group had a higher increase in; TLC (P < 0.01), VC (P < 0.001), P aw (P < 0.001) and HR (P < 0.05) and a higher decrease in MAP (P < 0.001). With GI in a sitting compared to a supine position, TLC, MAP, HR, P aw remained unchanged in the study group, while residual volume decreased in the supine position (P < 0.01). There was a difference between the groups in the increase in TLC; VC; P aw, HR and in the decrease in MAP with GI, however MAP, HR and P aw responded in similar way in both groups in a sitting as well as a supine position. If performed correctly, the risks of GI resulting in clinically significant hemodynamic changes is low, although syncope may still occur.

Effect of increased surface tension and assisted ventilation on /sup 99m/Tc-DTPA clearance

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

Jefferies, A.L.; Kawano, T.; Mori, S.

1988-02-01

Experiments were performed to determine the effects of conventional mechanical ventilation (CMV) and high-frequency oscillation (HFO) on the clearance of technetium-99m-labeled diethylenetriamine pentaacetate (/sup 99m/Tc-DTPA) from lungs with altered surface tension properties. A submicronic aerosol of /sup 99m/Tc-DTPA was insufflated into the lungs of anesthetized, tracheotomized rabbits before and 1 h after the administration of the aerosolized detergent dioctyl sodium sulfosuccinate (OT). Rabbits were ventilated by one of four methods: 1) spontaneous breathing; 2) CMV at 12 cmH2O mean airway pressure (MAP); 3) HFO at 12 cmH2O MAP; 4) HFO at 16 cmH2O MAP. Administration of OT resulted in decreasedmore » arterial PO2 (PaO2), increased lung wet-to-dry weight ratios, and abnormal lung pressure-volume relationships, compatible with increased surface tension. /sup 99m/Tc-DTPA clearance was accelerated after OT in all groups. The post-OT rate of clearance (k) was significantly faster (P less than 0.05) in the CMV at 12 cmH2O MAP (k = 7.57 +/- 0.71%/min (SE)) and HFO at 16 cmH2O MAP (k = 6.92 +/- 0.61%/min) groups than in the spontaneously breathing (k = 4.32 +/- 0.55%/min) and HFO at 12 cmH2O MAP (4.68 +/- 0.63%/min) groups. The clearance curves were biexponential in the former two groups. We conclude that pulmonary clearance of /sup 99m/Tc-DTPA is accelerated in high surface tension pulmonary edema, and this effect is enhanced by both conventional ventilation and HFO at high mean airway pressure.« less

Cardiovascular activity of rasagiline, a selective and potent inhibitor of mitochondrial monoamine oxidase B: comparison with selegiline

PubMed Central

Abassi, Zaid A; Binah, Ofer; Youdim, Moussa B H

2004-01-01

Selegiline is used for treating Parkinson's disease. Despite its efficacy, the clinical use of selegiline in combination with L-dihydroxphenylalanine in Parkinsonian patients is hampered by cardiovascular complications, such as hypotension. This study was designed to compare in rats the cardiovascular effects of selegiline and rasagiline, their metabolites L-methamphetamine and aminoindan (TVP-136), respectively, and the second rasagiline metabolite non-monoamine oxidase (MAO) inhibitor TVP-1022 (N-propargyl-1S(−)aminoindan). Intravenous (i.v.) administration of selegiline and rasagiline (1 mg kg−1) to anaesthetized rats (thiobutabarbital, 100 mg kg−1, i.p.) did not affect mean arterial pressure (MAP), carotid blood flow (CBF) or carotid vascular resistance (CVR). Selegiline (10 mg kg−1, i.v.) decreased MAP, CBF and increased CVR. In contrast, rasagiline (10 mg kg−1, i.v.) caused a small transient decrease in MAP, while CBF and CVR were unchanged. L-methamphetamine (1 mg kg−1, i.v.) administration provoked a dramatic and long-lasting depressor response, decreased CBF and increased CVR. In contrast, injection of aminoindan or TVP-1022 at a similar dose produced gradual nonsignificant decreases in MAP and CBF. Chronic oral treatment (21 days) of awake rats with selegiline at 10 mg kg−1 decreased systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP, whereas heart rate was unaffected. Since the effective MAO-B inhibitory and clinical dose of rasagiline is about one-tenth that of selegiline, administration of 1 mg kg−1 day−1 rasagiline resulted in moderate decreases in SBP, DBP, and MAP, which were significantly lower than those caused by the 10 mg kg−1 day−1 dose of selegiline. These findings indicate that rasagiline, when given at doses equivalent to selegiline, is less likely to be hypotensive. PMID:15339864

Cardiovascular activity of rasagiline, a selective and potent inhibitor of mitochondrial monoamine oxidase B: comparison with selegiline.

PubMed

Abassi, Zaid A; Binah, Ofer; Youdim, Moussa B H

2004-10-01

Selegiline is used for treating Parkinson's disease. Despite its efficacy, the clinical use of selegiline in combination with l-dihydroxphenylalanine in Parkinsonian patients is hampered by cardiovascular complications, such as hypotension. This study was designed to compare in rats the cardiovascular effects of selegiline and rasagiline, their metabolites l-methamphetamine and aminoindan (TVP-136), respectively, and the second rasagiline metabolite non-monoamine oxidase (MAO) inhibitor TVP-1022 (N-propargyl-1S(-)aminoindan). Intravenous (i.v.) administration of selegiline and rasagiline (1 mg kg(-1)) to anaesthetized rats (thiobutabarbital, 100 mg kg(-1), i.p.) did not affect mean arterial pressure (MAP), carotid blood flow (CBF) or carotid vascular resistance (CVR). Selegiline (10 mg kg(-1), i.v.) decreased MAP, CBF and increased CVR. In contrast, rasagiline (10 mg kg(-1), i.v.) caused a small transient decrease in MAP, while CBF and CVR were unchanged. l-methamphetamine (1 mg kg(-1), i.v.) administration provoked a dramatic and long-lasting depressor response, decreased CBF and increased CVR. In contrast, injection of aminoindan or TVP-1022 at a similar dose produced gradual nonsignificant decreases in MAP and CBF. Chronic oral treatment (21 days) of awake rats with selegiline at 10 mg kg(-1) decreased systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP, whereas heart rate was unaffected. Since the effective MAO-B inhibitory and clinical dose of rasagiline is about one-tenth that of selegiline, administration of 1 mg kg(-1) day(-1) rasagiline resulted in moderate decreases in SBP, DBP, and MAP, which were significantly lower than those caused by the 10 mg kg(-1) day(-1) dose of selegiline. These findings indicate that rasagiline, when given at doses equivalent to selegiline, is less likely to be hypotensive.

The cerebrovascular response to carbon dioxide in humans

PubMed Central

Battisti-Charbonney, A; Fisher, J; Duffin, J

2011-01-01

Abstract Carbon dioxide (CO2) increases cerebral blood flow and arterial blood pressure. Cerebral blood flow increases not only due to the vasodilating effect of CO2 but also because of the increased perfusion pressure after autoregulation is exhausted. Our objective was to measure the responses of both middle cerebral artery velocity (MCAv) and mean arterial blood pressure (MAP) to CO2 in human subjects using Duffin-type isoxic rebreathing tests. Comparisons of isoxic hyperoxic with isoxic hypoxic tests enabled the effect of oxygen tension to be determined. During rebreathing the MCAv response to CO2 was sigmoidal below a discernible threshold CO2 tension, increasing from a hypocapnic minimum to a hypercapnic maximum. In most subjects this threshold corresponded with the CO2 tension at which MAP began to increase. Above this threshold both MCAv and MAP increased linearly with CO2 tension. The sigmoidal MCAv response was centred at a CO2 tension close to normal resting values (overall mean 36 mmHg). While hypoxia increased the hypercapnic maximum percentage increase in MCAv with CO2 (overall means from 76.5 to 108%) it did not affect other sigmoid parameters. Hypoxia also did not alter the supra-threshold MCAv and MAP responses to CO2 (overall mean slopes 5.5% mmHg-1 and 2.1 mmHg mmHg−1, respectively), but did reduce the threshold (overall means from 51.5 to 46.8 mmHg). We concluded that in the MCAv response range below the threshold for the increase of MAP with CO2, the MCAv measurement reflects vascular reactivity to CO2 alone at a constant MAP. PMID:21521758

COBE DMR results and implications. [Differential Microwave Radiometer

NASA Technical Reports Server (NTRS)

Smoot, George F.

1992-01-01

This lecture presents early results obtained from the first six months of measurements of the Cosmic Microwave Background (CMB) by Differential Microwave Radiometers (DMR) aboard COBE and discusses significant cosmological implications. The DMR maps show the dipole anisotropy and some galactic emission but otherwise a spatially smooth early universe. The measurements are sufficiently precise that we must pay careful attention to potential systematic errors. Maps of galactic and local emission such as those produced by the FIRAS and DIRBE instruments will be needed to identify foregrounds from extragalactic emission and thus to interpret the results in terms of events in the early universe. The current DMR results are significant for Cosmology.

The mapping and differentiation of biological and environmental elemental signatures in the fossil remains of a 50 million year old bird

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

Egerton, Victoria M.; Wogelius, Roy A.; Norell, Mark A.

The preservation of fossils reflects the interplay of inorganic and organic chemical processes, which should be clearly differentiated to make interpretations about the biology of extinct organisms. A new coliiformes bird (mouse bird) from the ~50 million year old Green River Formation (Wyoming, USA) has here been analysed using synchrotron X-ray fluorescence and environmental scanning electron microscopy with an attached X-ray energy dispersive system (ESEM-EDS). The concentration and distribution of 16 elements (Si, P, S, Cl, K, Ca, Ti, Mg, Fe, Ni, Cu, Zn, As, Br, Ba, Hg) has been mapped for individual points on the sample. S, Cu andmore » Zn map distinctly within visibly preserved feathers and X-ray Absorption Spectroscopy (XAS) shows that S and Cu within the feathers are organically bound in a similar manner to modern feathers. The morphological preservation of the feathers, on both macro- and microscopic scales, is variable throughout the fossil and the differences in the lateral microfacies have resulted in a morphological preservation gradient. This study clearly differentiates endogenous organic remains from those representing exogenous overprinted geochemical precipitates and illustrates the chemical complexity of the overall taphonomic process.« less

The mapping and differentiation of biological and environmental elemental signatures in the fossil remains of a 50 million year old bird

DOE PAGES

Egerton, Victoria M.; Wogelius, Roy A.; Norell, Mark A.; ...

2015-01-22

The preservation of fossils reflects the interplay of inorganic and organic chemical processes, which should be clearly differentiated to make interpretations about the biology of extinct organisms. A new coliiformes bird (mouse bird) from the ~50 million year old Green River Formation (Wyoming, USA) has here been analysed using synchrotron X-ray fluorescence and environmental scanning electron microscopy with an attached X-ray energy dispersive system (ESEM-EDS). The concentration and distribution of 16 elements (Si, P, S, Cl, K, Ca, Ti, Mg, Fe, Ni, Cu, Zn, As, Br, Ba, Hg) has been mapped for individual points on the sample. S, Cu andmore » Zn map distinctly within visibly preserved feathers and X-ray Absorption Spectroscopy (XAS) shows that S and Cu within the feathers are organically bound in a similar manner to modern feathers. The morphological preservation of the feathers, on both macro- and microscopic scales, is variable throughout the fossil and the differences in the lateral microfacies have resulted in a morphological preservation gradient. This study clearly differentiates endogenous organic remains from those representing exogenous overprinted geochemical precipitates and illustrates the chemical complexity of the overall taphonomic process.« less

Ambulatory blood pressure monitoring in healthy children with parental hypertension.

PubMed

Alpay, Harika; Ozdemir, Nihal; Wühl, Elke; Topuzoğlu, Ahmet

2009-01-01

The aim of this study was to compare ambulatory blood pressure monitoring (ABPM) parameters in offspring with at least one hypertensive parent (HP) to offspring with normotensive parents (NP) and to determine whether gender of parent or child might influence the association between parental hypertension and blood pressure (BP). Eighty-nine healthy children (mean age 11.1 +/- 3.9 years) with HP and 90 controls (mean age 10.5 +/- 3.1 years) with NP were recruited. Age, gender, and height did not differ between the two groups, whereas children of HP had higher weight, body mass index (BMI), and waist circumference compared with healthy controls. No difference was found in casual BP between the two groups. In contrast, during ABPM daytime and nighttime mean systolic and diastolic BP and mean arterial pressure (MAP) standard deviation scores (SDS) were significantly elevated in children with HP. The mean percentage of nocturnal BP decline (dipping) was not significantly different between the two groups. Children with hypertensive mothers had higher daytime systolic and MAP SDS than controls; no such difference was detected for children with hypertensive fathers. Daytime systolic and MAP SDS were significantly elevated in boys with HP compared with boys with NP but failed to be significant in girls. Multiple linear regression analysis showed that parental history of hypertension (B = 0.29) and BMI (B = 0.03) were independently correlated with increase of daytime MAP SDS. Early changes in ambulatory BP parameters were present in healthy children of HP. BP in HP offspring was influenced by the gender of the affected parent and the offspring.

Restoring Redundancy to the MAP Propulsion System

NASA Technical Reports Server (NTRS)

O'Donnell, James R., Jr.; Davis, Gary T.; Ward, David K.; Bauer, Frank H. (Technical Monitor)

2002-01-01

The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE). Due to the MAP project's limited mass, power, and financial resources, a traditional reliability concept including fully redundant components was not feasible. The MAP design employs selective hardware redundancy, along with backup software modes and algorithms, to improve the odds of mission success. In particular, MAP's propulsion system, which is used for orbit maneuvers and momentum management, uses eight thrusters positioned and oriented in such a way that its thruster-based attitude control modes can maintain three-axis attitude control in the event of the failure of any one thruster.

Compensated vibrating optical fiber pressure measuring device

DOEpatents

Fasching, George E.; Goff, David R.

1987-01-01

A microbending optical fiber is attached under tension to a diaphragm to se a differential pressure applied across the diaphragm which it causes it to deflect. The fiber is attached to the diaphragm so that one portion of the fiber, attached to a central portion of the diaphragm, undergoes a change in tension; proportional to the differential pressure applied to the diaphragm while a second portion attached at the periphery of the diaphragm remains at a reference tension. Both portions of the fiber are caused to vibrate at their natural frequencies. Light transmitted through the fiber is attenuated by both portions of the tensioned sections of the fiber by an amount which increases with the curvature of fiber bending so that the light signal is modulated by both portions of the fiber at separate frequencies. The modulated light signal is transduced into a electrical signal. The separate modulation signals are detected to generate separate signals having frequencies corresponding to the reference and measuring vibrating sections of the continuous fiber, respectively. A signal proportional to the difference between these signals is generated which is indicative of the measured pressure differential across the diaphragm. The reference portion of the fiber is used to compensate the pressure signal for zero and span changes resulting from ambient temperature and humidity effects upon the fiber and the transducer fixture.

Comparing effects of perfusion and hydrostatic pressure on gene profiles of human chondrocyte.

PubMed

Zhu, Ge; Mayer-Wagner, Susanne; Schröder, Christian; Woiczinski, Matthias; Blum, Helmut; Lavagi, Ilaria; Krebs, Stefan; Redeker, Julia I; Hölzer, Andreas; Jansson, Volkmar; Betz, Oliver; Müller, Peter E

2015-09-20

Hydrostatic pressure and perfusion have been shown to regulate the chondrogenic potential of articular chondrocytes. In order to compare the effects of hydrostatic pressure plus perfusion (HPP) and perfusion (P) we investigated the complete gene expression profiles of human chondrocytes under HPP and P. A simplified bioreactor was constructed to apply loading (0.1 MPa for 2 h) and perfusion (2 ml) through the same piping by pressurizing the medium directly. High-density monolayer cultures of human chondrocytes were exposed to HPP or P for 4 days. Controls (C) were maintained in static cultures. Gene expression was evaluated by sequencing (RNAseq) and quantitative real-time PCR analysis. Both treatments changed gene expression levels of human chondrocytes significantly. Specifically, HPP and P increased COL2A1 expression and decreased COL1A1 and MMP-13 expression. Despite of these similarities, RNAseq revealed a list of cartilage genes including ACAN, ITGA10 and TNC, which were differentially expressed by HPP and P. Of these candidates, adhesion related molecules were found to be upregulated in HPP. Both HPP and P treatment had beneficial effects on chondrocyte differentiation and decreased catabolic enzyme expression. The study provides new insight into how hydrostatic pressure and perfusion enhance cartilage differentiation and inhibit catabolic effects. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of dipeptidyl peptidase-4 inhibition on circadian blood pressure during the development of salt-dependent hypertension in rats

PubMed Central

Sufiun, Abu; Rafiq, Kazi; Fujisawa, Yoshihide; Rahman, Asadur; Mori, Hirohito; Nakano, Daisuke; Kobori, Hiroyuki; Ohmori, Koji; Masaki, Tsutomu; Kohno, Masakazu; Nishiyama, Akira

2015-01-01

A growing body of evidence has indicated that dipeptidyl peptidase-4 (DPP-4) inhibitors have antihypertensive effects. Here, we aim to examine the effect of vildagliptin, a DPP-4-specific inhibitor, on blood pressure and its circadian-dipping pattern during the development of salt-dependent hypertension in Dahl salt-sensitive (DSS) rats. DSS rats were treated with a high-salt diet (8% NaCl) plus vehicle or vildagliptin (3 or 10 mg kg−1 twice daily by oral gavage) for 7 days. Blood pressure was measured by the telemetry system. High-salt diet for 7 days significantly increased the mean arterial pressure (MAP), systolic blood pressure (SBP) and were also associated with an extreme dipping pattern of blood pressure in DSS rats. Treatment with vildagliptin dose-dependently decreased plasma DPP-4 activity, increased plasma glucagon-like peptide 1 (GLP-1) levels and attenuated the development of salt-induced hypertension. Furthermore, vildagliptin significantly increased urine sodium excretion and normalized the dipping pattern of blood pressure. In contrast, intracerebroventricular infusion of vildagliptin (50, 500 or 2500 μg) did not alter MAP and heart rate in DSS rats. These data suggest that salt-dependent hypertension initially develops with an extreme blood pressure dipping pattern. The DPP-4 inhibitor, vildagliptin, may elicit beneficial antihypertensive effects, including the improvement of abnormal circadian blood pressure pattern, by enhancing urinary sodium excretion. PMID:25588850

Dissecting Stages of Human Kidney Development and Tumorigenesis with Surface Markers Affords Simple Prospective Purification of Nephron Stem Cells.

PubMed

Pode-Shakked, Naomi; Pleniceanu, Oren; Gershon, Rotem; Shukrun, Rachel; Kanter, Itamar; Bucris, Efrat; Pode-Shakked, Ben; Tam, Gal; Tam, Hadar; Caspi, Revital; Pri-Chen, Sara; Vax, Einav; Katz, Guy; Omer, Dorit; Harari-Steinberg, Orit; Kalisky, Tomer; Dekel, Benjamin

2016-03-29

When assembling a nephron during development a multipotent stem cell pool becomes restricted as differentiation ensues. A faulty differentiation arrest in this process leads to transformation and initiation of a Wilms' tumor. Mapping these transitions with respective surface markers affords accessibility to specific cell subpopulations. NCAM1 and CD133 have been previously suggested to mark human renal progenitor populations. Herein, using cell sorting, RNA sequencing, in vitro studies with serum-free media and in vivo xenotransplantation we demonstrate a sequential map that links human kidney development and tumorigenesis; In nephrogenesis, NCAM1(+)CD133(-) marks SIX2(+) multipotent renal stem cells transiting to NCAM1(+)CD133(+) differentiating segment-specific SIX2(-) epithelial progenitors and NCAM1(-)CD133(+) differentiated nephron cells. In tumorigenesis, NCAM1(+)CD133(-) marks SIX2(+) blastema that includes the ALDH1(+) WT cancer stem/initiating cells, while NCAM1(+)CD133(+) and NCAM1(-)CD133(+) specifying early and late epithelial differentiation, are severely restricted in tumor initiation capacity and tumor self-renewal. Thus, negative selection for CD133 is required for defining NCAM1(+) nephron stem cells in normal and malignant nephrogenesis.

Intercellular signaling pathways active during intervertebral disc growth, differentiation, and aging.

PubMed

Dahia, Chitra Lekha; Mahoney, Eric J; Durrani, Atiq A; Wylie, Christopher

2009-03-01

Intervertebral discs at different postnatal ages were assessed for active intercellular signaling pathways. To generate a spatial and temporal map of the signaling pathways active in the postnatal intervertebral disc (IVD). The postnatal IVD is a complex structure, consisting of 3 histologically distinct components, the nucleus pulposus, fibrous anulus fibrosus, and endplate. These differentiate and grow during the first 9 weeks of age in the mouse. Identification of the major signaling pathways active during and after the growth and differentiation period will allow functional analysis using mouse genetics and identify targets for therapy for individual components of the disc. Antibodies specific for individual cell signaling pathways were used on cryostat sections of IVD at different postnatal ages to identify which components of the IVD were responding to major classes of intercellular signal, including sonic hedgehog, Wnt, TGFbeta, FGF, and BMPs. We present a spatial/temporal map of these signaling pathways during growth, differentiation, and aging of the disc. During growth and differentiation of the disc, its different components respond at different times to different intercellular signaling ligands. Most of these are dramatically downregulated at the end of disc growth.

Elevated hydrostatic pressure triggers release of OPA1 and cytochrome C, and induces apoptotic cell death in differentiated RGC-5 cells

PubMed Central

Kim, Keun-Young; Lindsey, James D.; Angert, Mila; Patel, Ankur; Scott, Ray T.; Liu, Quan; Crowston, Jonathan G.; Ellisman, Mark H.; Perkins, Guy A.; Weinreb, Robert N.

2009-01-01

Purpose This study was conducted to determine whether elevated hydrostatic pressure alters mitochondrial structure, triggers release of the dynamin-related guanosine triphosphatase (GTPase) optic atrophy type 1 (OPA1) or cytochrome C from mitochondria, alters OPA1 gene expression, and can directly induce apoptotic cell death in cultured retinal ganglion cell (RGC)-5 cells. Methods Differentiated RGC-5 cells were exposed to 30 mmHg for three days in a pressurized incubator. As a control, differentiated RGC-5 cell cultures were incubated simultaneously in a conventional incubator. Live RGC-5 cells were then labeled with MitoTracker Red and mitochondrial morphology was assessed by fluorescence microscopy. Mitochondrial structural changes were also assessed by electron microscopy and three-dimenstional (3D) electron microscope tomography. OPA1 mRNA was measured by Taqman quantitative PCR. The cellular distribution of OPA1 protein and cytochrome C was assessed by immunocytochemistry and western blot. Caspase-3 activation was examined by western blot. Apoptotic cell death was evaluated by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method. Results Mitochondrial fission, characterized by the conversion of tubular fused mitochondria into isolated small organelles, was triggered after three days exposure to elevated hydrostatic pressure. Electron microscopy confirmed the fission and noted no changes to mitochondrial architecture, nor outer membrane rupture. Electron microscope tomography showed that elevated pressure depleted mitochondrial cristae content by fourfold. Elevated hydrostatic pressure increased OPA1 gene expression by 35±14% on day 2, but reduced expression by 36±4% on day 3. Total OPA1 protein content was not changed on day 2 or 3. However, pressure treatment induced release of OPA1 and cytochrome C from mitochondria to the cytoplasm. Elevated pressure also activated caspase-3 and induced apoptotic cell death. Conclusions Elevated hydrostatic pressure triggered mitochondrial changes including mitochondrial fission and abnormal cristae depletion, alteration of OPA1 gene expression, and release of OPA1 and cytochrome C into the cytoplasm before the onset of apoptotic cell death in differentiated RGC-5 cells. These results suggest that sustained moderate pressure elevation may directly damage RGC integrity by injuring mitochondria. PMID:19169378

Linear response formula for piecewise expanding unimodal maps

NASA Astrophysics Data System (ADS)

Baladi, Viviane; Smania, Daniel

2008-04-01

The average R(t)=\\int \\varphi\\,\\rmd \\mu_t of a smooth function phiv with respect to the SRB measure μt of a smooth one-parameter family ft of piecewise expanding interval maps is not always Lipschitz (Baladi 2007 Commun. Math. Phys. 275 839-59, Mazzolena 2007 Master's Thesis Rome 2, Tor Vergata). We prove that if ft is tangent to the topological class of f, and if ∂t ft|t = 0 = X circle f, then R(t) is differentiable at zero, and R'(0) coincides with the resummation proposed (Baladi 2007) of the (a priori divergent) series \\sum_{n=0}^\\infty \\int X(y) \\partial_y (\\varphi \\circ f^n)(y)\\,\\rmd \\mu_0(y) given by Ruelle's conjecture. In fact, we show that t map μt is differentiable within Radon measures. Linear response is violated if and only if ft is transversal to the topological class of f.

Use of acoustic classification of sidescan sonar data for mapping benthic habitat in the Northern Channel Islands, California

USGS Publications Warehouse

Cochrane, Guy R.; Lafferty, Kevin D.

2002-01-01

Highly reflective seafloor features imaged by sidescan sonar in nearshore waters off the Northern Channel Islands (California, USA) have been observed in subsequent submersible dives to be areas of thin sand covering bedrock. Adjacent areas of rocky seafloor, suitable as habitat for endangered species of abalone and rockfish, and encrusting organisms, cannot be differentiated from the areas of thin sand on the basis of acoustic backscatter (i.e. grey level) alone. We found second-order textural analysis of sidescan sonar data useful to differentiate the bottom types where data is not degraded by near-range distortion (caused by slant-range and ground-range corrections), and where data is not degraded by far-range signal attenuation. Hand editing based on submersible observations is necessary to completely convert the sidescan sonar image to a bottom character classification map suitable for habitat mapping.

Control of bed height in a fluidized bed gasification system

DOEpatents

Mehta, Gautam I.; Rogers, Lynn M.

1983-12-20

In a fluidized bed apparatus a method for controlling the height of the fdized bed, taking into account variations in the density of the bed. The method comprises taking simultaneous differential pressure measurements at different vertical elevations within the vessel, averaging the differential pressures, determining an average fluidized bed density, then periodically calculating a weighting factor. The weighting factor is used in the determination of the actual bed height which is used in controlling the fluidizing means.

Differential absorption lidars for remote sensing of atmospheric pressure and temperature profiles

NASA Technical Reports Server (NTRS)

Korb, C. Laurence; Schwemmer, Geary K.; Famiglietti, Joseph; Walden, Harvey; Prasad, Coorg

1995-01-01

A near infrared differential absorption lidar technique is developed using atmospheric oxygen as a tracer for high resolution vertical profiles of pressure and temperature with high accuracy. Solid-state tunable lasers and high-resolution spectrum analyzers are developed to carry out ground-based and airborne measurement demonstrations and results of the measurements presented. Numerical error analysis of high-altitude airborne and spaceborne experiments is carried out, and system concepts developed for their implementation.

Differential high pressure survival in stationary-phase Escherichia coli MG1655

NASA Astrophysics Data System (ADS)

Griffin, Patrick L.; Kish, Adrienne; Steele, Andrew; Hemley, Russell J.

2011-06-01

Hydrostatic pressure exerts a profound influence on nearly all facets of cellular structure and function with exposures to sufficiently high pressure leading to microbial inactivation. We report the first observation of a persistent, pressure-resistant subpopulation within stationary-phase samples of Escherichia coli MG1655, a mesophilic bacterium adapted to surface pressure. This high pressure-resistant subpopulation exhibits pressure survival ranging from 0.6 to 2.0 orders of magnitude greater survival than high pressure treatments at pressures of 225-400 MPa. We also examine some aspects of pressure treatment protocol that may influence the measurements of high pressure survival.

cudaMap: a GPU accelerated program for gene expression connectivity mapping

PubMed Central

2013-01-01

Background Modern cancer research often involves large datasets and the use of sophisticated statistical techniques. Together these add a heavy computational load to the analysis, which is often coupled with issues surrounding data accessibility. Connectivity mapping is an advanced bioinformatic and computational technique dedicated to therapeutics discovery and drug re-purposing around differential gene expression analysis. On a normal desktop PC, it is common for the connectivity mapping task with a single gene signature to take > 2h to complete using sscMap, a popular Java application that runs on standard CPUs (Central Processing Units). Here, we describe new software, cudaMap, which has been implemented using CUDA C/C++ to harness the computational power of NVIDIA GPUs (Graphics Processing Units) to greatly reduce processing times for connectivity mapping. Results cudaMap can identify candidate therapeutics from the same signature in just over thirty seconds when using an NVIDIA Tesla C2050 GPU. Results from the analysis of multiple gene signatures, which would previously have taken several days, can now be obtained in as little as 10 minutes, greatly facilitating candidate therapeutics discovery with high throughput. We are able to demonstrate dramatic speed differentials between GPU assisted performance and CPU executions as the computational load increases for high accuracy evaluation of statistical significance. Conclusion Emerging ‘omics’ technologies are constantly increasing the volume of data and information to be processed in all areas of biomedical research. Embracing the multicore functionality of GPUs represents a major avenue of local accelerated computing. cudaMap will make a strong contribution in the discovery of candidate therapeutics by enabling speedy execution of heavy duty connectivity mapping tasks, which are increasingly required in modern cancer research. cudaMap is open source and can be freely downloaded from http://purl.oclc.org/NET/cudaMap. PMID:24112435

Subtle differences in selective pressures applied on the envelope gene of HIV-1 in pregnant versus non-pregnant women.

PubMed

Ransy, Doris G; Lord, Etienne; Caty, Martine; Lapointe, Normand; Boucher, Marc; Diallo, Abdoulaye Baniré; Soudeyns, Hugo

2018-04-17

Pregnancy is associated with modulations of maternal immunity that contribute to foeto-maternal tolerance. To understand whether and how these alterations impact antiviral immunity, a detailed cross-sectional analysis of selective pressures exerted on HIV-1 envelope amino-acid sequences was performed in a group of pregnant (n = 32) and non-pregnant (n = 44) HIV-infected women in absence of treatment with antiretroviral therapy (ART). Independent of HIV-1 subtype, p-distance, dN and dS were all strongly correlated with one another but were not significantly different in pregnant as compared to non-pregnant patients. Differential levels of selective pressure applied on different Env subdomains displayed similar yet non-identical patterns between the two groups, with pressure applied on C1 being significantly lower in constant regions C1 and C2 than in V1, V2, V3 and C3. To draw a general picture of the selection applied on the envelope and compensate for inter-individual variations, we performed a binomial test on selection frequency data pooled from pregnant and non-pregnant women. This analysis uncovered 42 positions, present in both groups, exhibiting statistically-significant frequency of selection that invariably mapped to the surface of the Env protein, with the great majority located within epitopes recognized by Env-specific antibodies or sites associated with the development of cross-reactive neutralizing activity. The median frequency of occurrence of positive selection per site was significantly lower in pregnant versus non-pregnant women. Furthermore, examination of the distribution of positively selected sites using a hypergeometric test revealed that only 2 positions (D137 and S142) significantly differed between the 2 groups. Taken together, these result indicate that pregnancy is associated with subtle yet distinctive changes in selective pressures exerted on the HIV-1 Env protein that are compatible with transient modulations of maternal immunity. Copyright © 2018 Elsevier B.V. All rights reserved.

Heat stress attenuates the increase in arterial blood pressure during the cold pressor test.

PubMed

Cui, Jian; Shibasaki, Manabu; Low, David A; Keller, David M; Davis, Scott L; Crandall, Craig G

2010-11-01

The mechanisms by which heat stress impairs the control of blood pressure leading to compromised orthostatic tolerance are not thoroughly understood. A possible mechanism may be an attenuated blood pressure response to a given increase in sympathetic activity. This study tested the hypothesis that whole body heating attenuates the blood pressure response to a non-baroreflex-mediated sympathoexcitatory stimulus. Ten healthy subjects were instrumented for the measurement of integrated muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP), heart rate, sweat rate, and forearm skin blood flow. Subjects were exposed to a cold pressor test (CPT) by immersing a hand in an ice water slurry for 3 min while otherwise normothermic and while heat stressed (i.e., increase core temperature ~0.7°C via water-perfused suit). Mean responses from the final minute of the CPT were evaluated. In both thermal conditions CPT induced significant increases in MSNA and MAP without altering heart rate. Although the increase in MSNA to the CPT was similar between thermal conditions (normothermia: Δ14.0 ± 2.6; heat stress: Δ19.1 ± 2.6 bursts/min; P = 0.09), the accompanying increase in MAP was attenuated when subjects were heat stressed (normothermia: Δ25.6 ± 2.3, heat stress: Δ13.4 ± 3.0 mmHg; P < 0.001). The results demonstrate that heat stress can attenuate the pressor response to a sympathoexcitatory stimulus.

Characterizing Fishing Effort and Spatial Extent of Coastal Fisheries

PubMed Central

Stewart, Kelly R.; Lewison, Rebecca L.; Dunn, Daniel C.; Bjorkland, Rhema H.; Kelez, Shaleyla; Halpin, Patrick N.; Crowder, Larry B.

2010-01-01

Biodiverse coastal zones are often areas of intense fishing pressure due to the high relative density of fishing capacity in these nearshore regions. Although overcapacity is one of the central challenges to fisheries sustainability in coastal zones, accurate estimates of fishing pressure in coastal zones are limited, hampering the assessment of the direct and collateral impacts (e.g., habitat degradation, bycatch) of fishing. We compiled a comprehensive database of fishing effort metrics and the corresponding spatial limits of fisheries and used a spatial analysis program (FEET) to map fishing effort density (measured as boat-meters per km2) in the coastal zones of six ocean regions. We also considered the utility of a number of socioeconomic variables as indicators of fishing pressure at the national level; fishing density increased as a function of population size and decreased as a function of coastline length. Our mapping exercise points to intra and interregional ‘hotspots’ of coastal fishing pressure. The significant and intuitive relationships we found between fishing density and population size and coastline length may help with coarse regional characterizations of fishing pressure. However, spatially-delimited fishing effort data are needed to accurately map fishing hotspots, i.e., areas of intense fishing activity. We suggest that estimates of fishing effort, not just target catch or yield, serve as a necessary measure of fishing activity, which is a key link to evaluating sustainability and environmental impacts of coastal fisheries. PMID:21206903

Back to the Basics: Birmingham, Alabama, Measurement and Scale

ERIC Educational Resources Information Center

Handley, Lawrence R.; Lockwood, Catherine M.; Handley, Nathan

2005-01-01

"Back to the Basics: Birmingham, Alabama" is the fourth in a series of workshops that focus on teaching foundational map reading and spatial differentiation skills. It is the second published exercise from the Back to the Basics series developed by the Wetland Education through Maps and Aerial Photography (WETMAAP) Program (see…

Back to the Basics: Lake Tahoe, California/Nevada--Spatial Measurement

ERIC Educational Resources Information Center

Handley, Lawrence R.; Lockwood, Catherine M.; Handley, Nathan

2006-01-01

"Back to the Basics: South Lake Tahoe, California/Nevada" continues the series of exercises on teaching foundational map reading and spatial differentiation skills. It is the third published exercise from the Back to the Basics series developed by the Wetland Education through Maps and Aerial Photography (WETMAAP) Program. The current…

Communist China. Section 23. Weather and Climate. Part 3 - North China

DTIC Science & Technology

1964-06-01

Introduction 1 2. Climatic controls 2 a. General circulation and air masses 2 b. Migratory pressure systems and fronts 3 (1) Extratropical ...Sea-level pressure and surface airflow, January (map) 2 Fig. 2 Sea-level pressure and surface airflow, July (mop) 2 Fig. 3 Tracks of extratropical ...become weaker and less frequent as those of the invading monsoon become more prevalent. b. MIGRATORY PRESSURE SYSTEMS AND FRONTS (1) Extratropical

Effect of patient position and PEEP on hepatic, portal and central venous pressures during liver resection.

PubMed

Sand, L; Rizell, M; Houltz, E; Karlsen, K; Wiklund, J; Odenstedt Hergès, H; Stenqvist, O; Lundin, S

2011-10-01

It has been suggested that blood loss during liver resection may be reduced if central venous pressure (CVP) is kept at a low level. This can be achieved by changing patient position but it is not known how position changes affect portal (PVP) and hepatic (HVP) venous pressures. The aim of the study was to assess if changes in body position result in clinically significant changes in these pressures. We studied 10 patients undergoing liver resection. Mean arterial pressure (MAP) and CVP were measured using fluid-filled catheters, PVP and HVP with tip manometers. Measurements were performed in the horizontal, head up and head down tilt position with two positive end expiratory pressure (PEEP) levels. A 10° head down tilt at PEEP 5 cm H(2) O significantly increased CVP (11 ± 3 to 15 ± 3 mmHg) and MAP (72 ± 8 to 76 ± 8 mmHg) while head up tilt at PEEP 5 cm H(2) O decreased CVP (11 ± 3 to 6 ± 4 mmHg) and MAP (72 ± 8 to 63 ± 7 mmHg) with minimal changes in transhepatic venous pressures. Increasing PEEP from 5 to 10 resulted in small increases, around 1 mmHg in CVP, PVP and HVP. There was no significant correlation between changes in CVP vs. PVP and HVP during head up tilt and only a weak correlation between CVP and HVP by head down tilt. Changes of body position resulted in marked changes in CVP but not in HVPs. Head down or head up tilt to reduce venous pressures in the liver may therefore not be effective measures to reduce blood loss during liver surgery. 2011 The Authors Acta Anaesthesiologica Scandinavica, 2011 The Acta Anaesthesiologica Scandinavica Foundation.

Defective Number Sense or Impaired Access? Differential Impairments in Different Subgroups of Children With Mathematics Difficulties.

PubMed

Wong, Terry T-Y; Ho, Connie S-H; Tang, Joey

2017-01-01

Developmental dyscalculia (DD) is a specific learning disability in mathematics that affects around 6% of the population. Currently, the core deficit of DD remains unknown. While the number sense deficit hypothesis suggests that the core deficit of DD lies in the inability to represent nonsymbolic numerosity, the access deficit hypothesis suggests that the origin of this disability lies in the inability to associate numbers with the underlying magnitude representation. The present study compared the performance of DDs with their low-achieving (LA) and normally achieving peers in nonsymbolic numerosity processing and number-magnitude mapping over 1 year (from kindergarten to 1st grade). The results demonstrated differential impairments in different subgroups of children with mathematics difficulties. While DDs showed deficits in both nonsymbolic numerosity processing and number-magnitude mapping, LAs showed deficit only in the number-magnitude mapping. Furthermore, the deficit in number-magnitude mapping among the DD group was partially explained by their number sense deficit. The number sense deficit hypothesis is supported. Theoretical and practical implications are discussed. © Hammill Institute on Disabilities 2015.

Mapping optical path length and image enhancement using quantitative orientation-independent differential interference contrast microscopy

PubMed Central

Shribak, Michael; Larkin, Kieran G.; Biggs, David

2017-01-01

Abstract. We describe the principles of using orientation-independent differential interference contrast (OI-DIC) microscopy for mapping optical path length (OPL). Computation of the scalar two-dimensional OPL map is based on an experimentally received map of the OPL gradient vector field. Two methods of contrast enhancement for the OPL image, which reveal hardly visible structures and organelles, are presented. The results obtained can be used for reconstruction of a volume image. We have confirmed that a standard research grade light microscope equipped with the OI-DIC and 100×/1.3 NA objective lens, which was not specially selected for minimum wavefront and polarization aberrations, provides OPL noise level of ∼0.5  nm and lateral resolution if ∼300  nm at a wavelength of 546 nm. The new technology is the next step in the development of the DIC microscopy. It can replace standard DIC prisms on existing commercial microscope systems without modification. This will allow biological researchers that already have microscopy setups to expand the performance of their systems. PMID:28060991

Partial differential equations constrained combinatorial optimization on an adiabatic quantum computer

NASA Astrophysics Data System (ADS)

Chandra, Rishabh

Partial differential equation-constrained combinatorial optimization (PDECCO) problems are a mixture of continuous and discrete optimization problems. PDECCO problems have discrete controls, but since the partial differential equations (PDE) are continuous, the optimization space is continuous as well. Such problems have several applications, such as gas/water network optimization, traffic optimization, micro-chip cooling optimization, etc. Currently, no efficient classical algorithm which guarantees a global minimum for PDECCO problems exists. A new mapping has been developed that transforms PDECCO problem, which only have linear PDEs as constraints, into quadratic unconstrained binary optimization (QUBO) problems that can be solved using an adiabatic quantum optimizer (AQO). The mapping is efficient, it scales polynomially with the size of the PDECCO problem, requires only one PDE solve to form the QUBO problem, and if the QUBO problem is solved correctly and efficiently on an AQO, guarantees a global optimal solution for the original PDECCO problem.

Rat chromosome 1: regional localization of seven genes (Slc9a3, Srd5a1, Esr, Tcp1, Grik5, Tnnt3, Jak2) and anchoring of the genetic linkage map to the cytogenetic map.

PubMed

Szpirer, C; Szpirer, J; Tissir, F; Stephanova, E; Vanvooren, P; Kurtz, T W; Iwai, N; Inagami, T; Pravenec, M; Kren, V; Klinga-Levan, K; Levan, G

1997-09-01

Seven genes were regionally localized on rat Chromosome (Chr) 1, from 1p11 to 1q42, and two of these genes were also included in a linkage map. This mapping work integrates the genetic linkage map and the cytogenetic map, and allows us to orient the linkage map with respect to the centromere, and to deduce the approximate position of the centromere in the linkage map. These mapping data also indicate that the Slc9a3 gene, encoding the Na+/H+ exchanger 3, is an unlikely candidate for the blood pressure loci assigned to rat Chr 1. These new localizations expand comparative mapping between rat Chr 1 and mouse or human chromosomes.

The Effects of Core Composition on Iron Isotope Fractionation During Planetary Differentiation

NASA Astrophysics Data System (ADS)

Elardo, S. M.; Shahar, A.; Caracas, R.; Mock, T. D.; Sio, C. K. I.

2018-05-01

High pressure and temperature isotope exchange experiments and density functional theory calculations show how the composition of planetary cores affects the fractionation of iron isotopes during planetary differentiation.

Control of blood pressure, appetite, and glucose by leptin in mice lacking leptin receptors in proopiomelanocortin neurons.

PubMed

do Carmo, Jussara M; da Silva, Alexandre A; Cai, Zhengwei; Lin, Shuying; Dubinion, John H; Hall, John E

2011-05-01

Although the central nervous system melanocortin system is an important regulator of energy balance, the role of proopiomelanocortin (POMC) neurons in mediating the chronic effects of leptin on appetite, blood pressure, and glucose regulation is unknown. Using Cre/loxP technology we tested whether leptin receptor deletion in POMC neurons (LepR(flox/flox)/POMC-Cre mice) attenuates the chronic effects of leptin to increase mean arterial pressure (MAP), enhance glucose use and oxygen consumption, and reduce appetite. LepR(flox/flox)/POMC-Cre, wild-type, LepR(flox/flox), and POMC-Cre mice were instrumented for MAP and heart rate measurement by telemetry and venous catheters for infusions. LepR(flox/flox)/POMC-Cre mice were heavier, hyperglycemic, hyperinsulinemic, and hyperleptinemic compared with wild-type, LepR(flox/flox), and POMC-Cre mice. Despite exhibiting features of metabolic syndrome, LepR(flox/flox)/POMC-Cre mice had normal MAP and heart rate compared with LepR(flox/flox) but lower MAP and heart rate compared with wild-type mice. After a 5-day control period, leptin was infused (2 μg/kg per minute, IV) for 7 days. In control mice, leptin increased MAP by ≈5 mm Hg despite decreasing food intake by ≈35%. In contrast, leptin infusion in LepR(flox/flox)/POMC-Cre mice reduced MAP by ≈3 mm Hg and food intake by ≈28%. Leptin significantly decreased insulin and glucose levels in control mice but not in LepR(flox/flox)/POMC-Cre mice. Leptin increased oxygen consumption in LepR(flox/flox)/POMC-Cre and wild-type mice. Activation of POMC neurons is necessary for the chronic effects of leptin to raise MAP and reduce insulin and glucose levels, whereas leptin receptors in other areas of the brain other than POMC neurons appear to play a key role in mediating the chronic effects of leptin on appetite and oxygen consumption.

Identification and analysis of evolutionary selection pressures acting at the molecular level in five forkhead subfamilies.

PubMed

Fetterman, Christina D; Rannala, Bruce; Walter, Michael A

2008-09-24

Members of the forkhead gene family act as transcription regulators in biological processes including development and metabolism. The evolution of forkhead genes has not been widely examined and selection pressures at the molecular level influencing subfamily evolution and differentiation have not been explored. Here, in silico methods were used to examine selection pressures acting on the coding sequence of five multi-species FOX protein subfamily clusters; FoxA, FoxD, FoxI, FoxO and FoxP. Application of site models, which estimate overall selection pressures on individual codons throughout the phylogeny, showed that the amino acid changes observed were either neutral or under negative selection. Branch-site models, which allow estimated selection pressures along specified lineages to vary as compared to the remaining phylogeny, identified positive selection along branches leading to the FoxA3 and Protostomia clades in the FoxA cluster and the branch leading to the FoxO3 clade in the FoxO cluster. Residues that may differentiate paralogs were identified in the FoxA and FoxO clusters and residues that differentiate orthologs were identified in the FoxA cluster. Neutral amino acid changes were identified in the forkhead domain of the FoxA, FoxD and FoxP clusters while positive selection was identified in the forkhead domain of the Protostomia lineage of the FoxA cluster. A series of residues under strong negative selection adjacent to the N- and C-termini of the forkhead domain were identified in all clusters analyzed suggesting a new method for refinement of domain boundaries. Extrapolation of domains among cluster members in conjunction with selection pressure information allowed prediction of residue function in the FoxA, FoxO and FoxP clusters and exclusion of known domain function in residues of the FoxA and FoxI clusters. Consideration of selection pressures observed in conjunction with known functional information allowed prediction of residue function and refinement of domain boundaries. Identification of residues that differentiate orthologs and paralogs provided insight into the development and functional consequences of paralogs and forkhead subfamily composition differences among species. Overall we found that after gene duplication of forkhead family members, rapid differentiation and subsequent fixation of amino acid changes through negative selection has occurred.

Pulse thermal energy transport/storage system

DOEpatents

Weislogel, Mark M.

1992-07-07

A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

Optical fiber Bragg grating-instrumented silicone liner for interface pressure measurement within prosthetic sockets of lower-limb amputees.

PubMed

Al-Fakih, Ebrahim; Arifin, Nooranida; Pirouzi, Gholamhossein; Mahamd Adikan, Faisal Rafiq; Shasmin, Hanie Nadia; Abu Osman, Noor Azuan

2017-08-01

This paper presents a fiber Bragg grating (FBG)-instrumented prosthetic silicone liner that provides cushioning for the residual limb and can successfully measure interface pressures inside prosthetic sockets of lower-limb amputees in a simple and practical means of sensing. The liner is made of two silicone layers between which 12 FBG sensors were embedded at locations of clinical interest. The sensors were then calibrated using a custom calibration platform that mimics a real-life situation. Afterward, a custom gait simulating machine was built to test the liner performance during an amputee's simulated gait. To validate the findings, the results were compared to those obtained by the commonly used F-socket mats. As the statistical findings reveal, both pressure mapping methods measured the interface pressure in a consistent way, with no significant difference (P-values ≥0.05). This pressure mapping technique in the form of a prosthetic liner will allow prosthetics professionals to quickly and accurately create an overall picture of the interface pressure distribution inside sockets in research and clinical settings, thereby improving the socket fit and amputee's satisfaction. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Effect of interpolation on parameters extracted from seating interface pressure arrays.

PubMed

Wininger, Michael; Crane, Barbara

2014-01-01

Interpolation is a common data processing step in the study of interface pressure data collected at the wheelchair seating interface. However, there has been no focused study on the effect of interpolation on features extracted from these pressure maps, nor on whether these parameters are sensitive to the manner in which the interpolation is implemented. Here, two different interpolation paradigms, bilinear versus bicubic spline, are tested for their influence on parameters extracted from pressure array data and compared against a conventional low-pass filtering operation. Additionally, analysis of the effect of tandem filtering and interpolation, as well as the interpolation degree (interpolating to 2, 4, and 8 times sampling density), was undertaken. The following recommendations are made regarding approaches that minimized distortion of features extracted from the pressure maps: (1) filter prior to interpolate (strong effect); (2) use of cubic interpolation versus linear (slight effect); and (3) nominal difference between interpolation orders of 2, 4, and 8 times (negligible effect). We invite other investigators to perform similar benchmark analyses on their own data in the interest of establishing a community consensus of best practices in pressure array data processing.

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

Davis, John R.; Brubaker, Erik; Vetter, Kai

In an effort to characterize the fast neutron radiation background, 16 EJ-309 liquid scintillator cells were installed in the Radiological Multi-sensor Analysis Platform (RadMAP) to collect data in the San Francisco Bay Area. Each fast neutron event was associated with specific weather metrics (pressure, temperature, absolute humidity) and GPS coordinates. Furthermore, the expected exponential dependence of the fast neutron count rate on atmospheric pressure was demonstrated and event rates were subsequently adjusted given the measured pressure at the time of detection. Pressure adjusted data was also used to investigate the influence of other environmental conditions on the neutron background rate.more » Using National Oceanic and Atmospheric Administration (NOAA) coastal area lidar data, an algorithm was implemented to approximate sky-view factors (the total fraction of visible sky) for points along RadMAPs route. In the three areas we analyzed, San Francisco, Downtown Oakland, and Berkeley, all demonstrated a suppression in the background rate of over 50% for the range of sky-view factors measured. This effect, which is due to the shielding of cosmic-ray produced neutrons by surrounding buildings, was comparable to the pressure influence which yielded a 32% suppression in the count rate over the range of pressures measured.« less

Multiplexing Transducers Based on Tunnel-Diode Oscillators

NASA Technical Reports Server (NTRS)

Chui, Talso; Penanen, Konstantin; Young, Joseph

2006-01-01

Multiplexing and differential transducers based on tunnel-diode oscillators (TDOs) would be developed, according to a proposal, for operation at very low and/or widely varying temperatures in applications that involve requirements to minimize the power and mass of transducer electronic circuitry. It has been known since 1975 that TDOs are useful for making high-resolution (of the order of 10(exp -9)) measurements at low temperatures. Since that time, TDO transducers have been found to offer the following additional advantages, which the present proposal is intended to exploit: TDO transducers can operate at temperatures ranging from 1 K to about 400 K. Most electronic components other than tunnel diodes do not operate over such a wide temperature range. TDO transducers can be made to operate at very low power - typically, <1 mW. Inasmuch as the response of a TDO transducer is a small change in an arbitrarily set oscillation frequency, the outputs of many TDOs operating at sufficiently different set frequencies can be multiplexed through a single wire. Inasmuch as frequencies can be easily subtracted by means of mixing circuitry, one can easily use two TDOs to make differential measurements. Differential measurements are generally more precise and less susceptible to environmental variations than are absolute measurements. TDO transducers are tolerant to ionizing radiation. Ultimately, the response of a TDO transducer is measured by use of a frequency counter. Because frequency counting can be easily implemented by use of clock signals available from most microprocessors, it is not necessary to incorporate additional readout circuitry that would, if included, add to the mass and power consumption of the transducer circuitry. In one example of many potential variations on the basic theme of the proposal, the figure schematically depicts a conceptual differential-pressure transducer containing a symmetrical pair of TDOs. The differential pressure would be exerted on an electrically conductive and grounded diaphragm, which, at zero differential pressure, would nominally be sprung to a middle position between two capacitor plates that would be parts of the two TDOs. The frequencies of the two TDOs would vary in opposite directions as variations in differential pressure bent the diaphragm away from one capacitor plate and toward the other. The outputs of the TDOs would be mixed and lowpass filtered to obtain a signal at the difference between the frequencies of the two TDOs. The difference frequency would be measured by a frequency counter and converted to differential pressure by a computer.

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2013 CFR

2013-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2010 CFR

2010-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2014 CFR

2014-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2011 CFR

2011-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

14 CFR 25.841 - Pressurized cabins.

Code of Federal Regulations, 2012 CFR

2012-01-01

... differentials up to the maximum relief valve setting in combination with landing loads. (8) The pressure sensors... located and the sensing system designed so that, in the event of loss of cabin pressure in any passenger... increase the hazards resulting from decompression. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., a fixed trycock line, or a differential pressure liquid level gauge must be used as the primary... control for filling. (2) The design pressure of each liquid level gauging device must be at least that of... openings for dip tube gauging devices and pressure gauges in flammable cryogenic liquid service must be...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

49 CFR 178.338-14 - Gauging devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... gauging devices, which accurately indicate the maximum permitted liquid level at the loading pressure, in... trycock line, or a differential pressure liquid level gauge must be used as the primary control for... filling. (2) The design pressure of each liquid level gauging device must be at least that of the tank. (3...

Saturation meter

DOEpatents

Gregurech, S.

1984-08-01

A saturation meter for use in a pressurized water reactor plant comprising a differential pressure transducer having a first and second pressure sensing means and an alarm. The alarm is connected to the transducer and is preset to activate at a level of saturation prior to the formation of a steam void in the reactor vessel.

49 CFR 232.103 - General requirements for all train brake systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the air compressor governor starting or loading pressure. (l) Except as otherwise provided in this... brake pipe air pressure: Road Service 90 Switch Service 60 (2) Minimum differential between brake pipe and main reservoir air pressures, with brake valve in running position 15 (3) Safety valve for...

49 CFR 232.103 - General requirements for all train brake systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the air compressor governor starting or loading pressure. (l) Except as otherwise provided in this... brake pipe air pressure: Road Service 90 Switch Service 60 (2) Minimum differential between brake pipe and main reservoir air pressures, with brake valve in running position 15 (3) Safety valve for...

Chondrocyte response to cyclic hydrostatic pressure in alginate versus pellet culture.

PubMed

Elder, Steven H; Sanders, Shawn W; McCulley, William R; Marr, Misti L; Shim, Joon W; Hasty, Karen A

2006-04-01

Cells are often cultured at high density (e.g., confluent monolayer and as pellets) to promote chondrogenic differentiation and to maintain the chondrocyte phenotype. They are also frequently suspended in hydrogels such as agarose or alginate for the same purposes. These culture techniques differ markedly with respect to frequency of direct contact between cells and overall intercellular spacing. Because these factors may significantly affect mechanotransduction, the purpose of this study was to determine if the response of articular chondrocytes to cyclic hydrostatic pressure would depend on the culture condition. Primary articular chondrocytes from young and mature pigs were cultured either as pellets or suspended in alginate beads. Both groups were exposed to dynamic hydrostatic pressure (4 MPa, 1 Hz, 5400 cycles per day) for 7 days. Cell proliferation was unaffected by pressure, but pressurized chondrocytes in pellet culture had significantly greater sGAG content and incorporated [3H]proline at a higher rate than nonpressurized controls. Electron microscopy revealed a fibrous extracellular matrix (ECM) surrounding pellets, but not cells in alginate. In addition, expression of Connexin 43 (Cx43) mRNA was slightly lower in alginate than in pellet cultures and was not significantly altered by loading. Thus, metabolic response of chondrocytes to dynamic hydrostatic pressure was affected by culture technique; chondrocytes cultured as pellets exhibited the classical anabolic response to dynamic hydrostatic pressure, but those in alginate did not. Although cell-ECM interaction could be important, the differential response is not likely attributable to differential expression of Cx43 mRNA. Copyright 2006 Orthopaedic Research Society

Recovering Aerodynamic Side Loads on Rocket Nozzles using Quasi-Static Strain-Gage Measurements

NASA Technical Reports Server (NTRS)

Brown, Andrew; Ruf, Joseph H.; McDaniels, David M.

2009-01-01

During over-expanded operation of rocket nozzles, which is defined to be when the exit pressure is greater than internal pressure over some part of the nozzle, the nozzle will experience a transverse forcing function due to the pressure differential across the nozzle wall. Over-expansion occurs during the nozzle start-up and shutdown transient, even in high-altitude engines, because most test facilities cannot completely reproduce the near-vacuum pressures at those altitudes. During this transient, the pressure differential moves axially down the nozzle as it becomes pressurized, but this differential is never perfectly symmetric circumferentially. The character of the forcing function is highly complex and defined by a series of restricted and free shock separations. The subject of this paper is the determination of the magnitude of this loading during sub-scale testing via measurement of the structural dynamic response of the nozzle and its support structure. An initial attempt at back-calculating this load using the inverse of the transfer function was performed, but this attempt was shown to be highly susceptible to numerical error. The final method chosen was to use statically calibrated strain data and to filter out the system fundamental frequency such that the measured response yields close to the correct dynamic loading function. This method was shown to capture 93% of the pressure spectral energy using controlled load shaker testing. This method is one of the only practical ways for the inverse determination of the forcing function for non-stationary excitations, and, to the authors' knowledge, has not been described in the literature to date.

Mobility of an elastic glove for extravehicular activity without prebreathing.

PubMed

Tanaka, Kunihiko; Ikeda, Mizuki; Mochizuki, Yosuke; Katafuchi, Tetsuro

2011-09-01

The current U.S. extravehicular activity (EVA) suit is pressurized at 0.29 atm, which is much lower than the pressures of sea level and inside a space station. Higher pressure can reduce the risk of decompression sickness (DCS), but mobility would be sacrificed. We have demonstrated that a glove and sleeve made of elastic material increased mobility when compared with those made of nonelastic material, such as that found in the current suit. We hypothesized that an elastic glove of 0.65 atm that has no risk of DCS also has greater mobility compared with a non-elastic glove of 0.29 atm. The right hands of 10 healthy volunteers were studied in a chamber with their bare hands at normal ambient pressure, after donning a non-elastic glove with a pressure differential of 0.29 atm, and after donning an elastic glove with a pressure differential of 0.29 and 0.65 atm. Range of motion (ROM) of the index finger and surface electromyography (EMG) amplitudes during finger flexion were measured. ROM with gloves was significantly smaller than that of bare hands, but was similar between conditions of gloves regardless of elasticity and pressure differentials. However, EMG amplitudes with the elastic glove of 0.29 and 0.65 atm were significantly smaller than those with the non-elastic glove of 0.29 atm. The results suggest that mobility of the elastic glove of 0.65 atm may be better than that of the non-elastic glove of 0.29 atm, similar to that used in the current EVA suit.

Connectivity Mapping for Candidate Therapeutics Identification Using Next Generation Sequencing RNA-Seq Data

PubMed Central

McArt, Darragh G.; Dunne, Philip D.; Blayney, Jaine K.; Salto-Tellez, Manuel; Van Schaeybroeck, Sandra; Hamilton, Peter W.; Zhang, Shu-Dong

2013-01-01

The advent of next generation sequencing technologies (NGS) has expanded the area of genomic research, offering high coverage and increased sensitivity over older microarray platforms. Although the current cost of next generation sequencing is still exceeding that of microarray approaches, the rapid advances in NGS will likely make it the platform of choice for future research in differential gene expression. Connectivity mapping is a procedure for examining the connections among diseases, genes and drugs by differential gene expression initially based on microarray technology, with which a large collection of compound-induced reference gene expression profiles have been accumulated. In this work, we aim to test the feasibility of incorporating NGS RNA-Seq data into the current connectivity mapping framework by utilizing the microarray based reference profiles and the construction of a differentially expressed gene signature from a NGS dataset. This would allow for the establishment of connections between the NGS gene signature and those microarray reference profiles, alleviating the associated incurring cost of re-creating drug profiles with NGS technology. We examined the connectivity mapping approach on a publicly available NGS dataset with androgen stimulation of LNCaP cells in order to extract candidate compounds that could inhibit the proliferative phenotype of LNCaP cells and to elucidate their potential in a laboratory setting. In addition, we also analyzed an independent microarray dataset of similar experimental settings. We found a high level of concordance between the top compounds identified using the gene signatures from the two datasets. The nicotine derivative cotinine was returned as the top candidate among the overlapping compounds with potential to suppress this proliferative phenotype. Subsequent lab experiments validated this connectivity mapping hit, showing that cotinine inhibits cell proliferation in an androgen dependent manner. Thus the results in this study suggest a promising prospect of integrating NGS data with connectivity mapping. PMID:23840550

Assessing potential climate change pressures across the conterminous United States: mapping plant hardiness zones, heat zones, growing degree days, and cumulative drought severity throughout this century

Treesearch

Stephen N. Matthews; Louis R. Iverson; Matthew P. Peters; Anantha M. Prasad

2018-01-01

The maps and tables presented here represent potential variability of projected climate change across the conterminous United States during three 30-year periods in this century and emphasizes the importance of evaluating multiple signals of change across large spatial domains. Maps of growing degree days, plant hardiness zones, heat zones, and cumulative drought...

User-interactive electronic skin for instantaneous pressure visualization

NASA Astrophysics Data System (ADS)

Wang, Chuan; Hwang, David; Yu, Zhibin; Takei, Kuniharu; Park, Junwoo; Chen, Teresa; Ma, Biwu; Javey, Ali

2013-10-01

Electronic skin (e-skin) presents a network of mechanically flexible sensors that can conformally wrap irregular surfaces and spatially map and quantify various stimuli. Previous works on e-skin have focused on the optimization of pressure sensors interfaced with an electronic readout, whereas user interfaces based on a human-readable output were not explored. Here, we report the first user-interactive e-skin that not only spatially maps the applied pressure but also provides an instantaneous visual response through a built-in active-matrix organic light-emitting diode display with red, green and blue pixels. In this system, organic light-emitting diodes (OLEDs) are turned on locally where the surface is touched, and the intensity of the emitted light quantifies the magnitude of the applied pressure. This work represents a system-on-plastic demonstration where three distinct electronic components—thin-film transistor, pressure sensor and OLED arrays—are monolithically integrated over large areas on a single plastic substrate. The reported e-skin may find a wide range of applications in interactive input/control devices, smart wallpapers, robotics and medical/health monitoring devices.

User-interactive electronic skin for instantaneous pressure visualization.

PubMed

Wang, Chuan; Hwang, David; Yu, Zhibin; Takei, Kuniharu; Park, Junwoo; Chen, Teresa; Ma, Biwu; Javey, Ali

2013-10-01

Electronic skin (e-skin) presents a network of mechanically flexible sensors that can conformally wrap irregular surfaces and spatially map and quantify various stimuli. Previous works on e-skin have focused on the optimization of pressure sensors interfaced with an electronic readout, whereas user interfaces based on a human-readable output were not explored. Here, we report the first user-interactive e-skin that not only spatially maps the applied pressure but also provides an instantaneous visual response through a built-in active-matrix organic light-emitting diode display with red, green and blue pixels. In this system, organic light-emitting diodes (OLEDs) are turned on locally where the surface is touched, and the intensity of the emitted light quantifies the magnitude of the applied pressure. This work represents a system-on-plastic demonstration where three distinct electronic components--thin-film transistor, pressure sensor and OLED arrays--are monolithically integrated over large areas on a single plastic substrate. The reported e-skin may find a wide range of applications in interactive input/control devices, smart wallpapers, robotics and medical/health monitoring devices.

Forces and dynamics in epithelial domes of controlled size and shape

NASA Astrophysics Data System (ADS)

Latorre-Ibars, Ernest; Casares, Laura; Gomez-Gonzalez, Manuel; Uroz, Marina; Arroyo, Marino; Trepat, Xavier

Mechanobiology of epithelia plays a central role in morphogenesis, wound healing, and tumor progression. Its current understanding relies on mechanical measurements on flat epithelial layers. However, most epithelia in vivo exhibit a curved 3D shape enclosing a pressurized lumen. Using soft micropatterned substrates we produce massive parallel arrays of epithelial domes with controlled size and basal shape. We measure epithelial traction, tension, and luminal pressure in epithelial domes. The local stress tensor on the freestanding epithelial membrane is then mapped by combining measured luminal pressure and local curvature. We show that tension and cell shape are highly anisotropic and vary along the meridional position of the domes. Finally, we establish constitutive relations between shape, tension, and pressure during perturbations of the contractile machinery, osmotic shocks, and spontaneous fluctuations of dome volume. Our findings contradict a description of the epithelium as a fluid capillary surface. Cells in the dome are unable to relax into a uniform and isotropic tensional state through sub- and supra-cellular rearrangements. Mapping epithelial shape, tension, and pressure will enable quantitative studies of mechanobiology in 3D epithelia of controlled size and shape.

Differential screening and mass mapping of proteins from premalignant and cancer cell lines using nonporous reversed-phase HPLC coupled with mass spectrometric analysis.

PubMed

Chong, B E; Hamler, R L; Lubman, D M; Ethier, S P; Rosenspire, A J; Miller, F R

2001-03-15

Nonporous (NPS) RP-HPLC has been used to rapidly separate proteins from whole cell lysates of human breast cell lines. The nonporous separation involves the use of hard-sphere silica beads of 1.5-microm diameter coated with C18, which can be used to separate proteins ranging from 5 to 90 kDa. Using only 30-40 microg of total protein, the protein molecular weights are detectable on-line using an ESI-oaTOF MS. Of hundreds of proteins detected in this mass range, approxinately 75-80 are more highly expressed. The molecular weight profiles can be displayed as a mass map analogous to a virtual "1-D gel" and differentially expressed proteins can be compared by image analysis. The separated proteins can also be detected by UV absorption and differentially expressed proteins quantified. The eluting proteins can be collected in the liquid phase and the molecular weight and peptide maps determined by MALDI-TOF MS for identification. It is demonstrated that the expressed protein profiles change during neoplastic progression and that many oncoproteins are readily detected. It is also shown that the response of premalignant cancer cells to estradiol can be rapidly screened by this method, demonstrating significant changes in response to an external agent. Ultimately, the proteins can be studied by peptide mapping to search for posttranslational modifications of the oncoproteins accompanying progression.

Calcium Hydroxide-induced Proliferation, Migration, Osteogenic Differentiation, and Mineralization via the Mitogen-activated Protein Kinase Pathway in Human Dental Pulp Stem Cells.

PubMed

Chen, Luoping; Zheng, Lisha; Jiang, Jingyi; Gui, Jinpeng; Zhang, Lingyu; Huang, Yan; Chen, Xiaofang; Ji, Jing; Fan, Yubo

2016-09-01

Calcium hydroxide has been extensively used as the gold standard for direct pulp capping in clinical dentistry. It induces proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying mechanisms are still unclear. The aim of this study was to investigate the role of the mitogen-activated protein (MAP) kinase pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Human DPSCs between passages 3 and 6 were used. DPSCs were preincubated with inhibitors of MAP kinases and cultured with calcium hydroxide. The phosphorylated MAP kinases were detected by Western blot analysis. Cell viability was analyzed via the methylthiazol tetrazolium assay. Cell migration was estimated using the wound healing assay. Alkaline phosphatase (ALP) expression was analyzed using the ALP staining assay. Mineralization was studied by alizarin red staining analysis. Calcium hydroxide significantly promoted the phosphorylation of the c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase. The inhibition of JNK and p38 signaling abolished calcium hydroxide-induced proliferation of DPSCs. The inhibition of JNK, p38, and extracellular signal-regulated kinase signaling suppressed the migration, ALP expression, and mineralization of DPSCs. Our study showed that the MAP kinase pathway was involved in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Analysis Of Direct Numerical Simulation Results Of Adverse Pressure Gradient Boundary Layer Through Anisotropy Invariant Mapping And Comparison With The Rans Simulations

NASA Astrophysics Data System (ADS)

Gungor, Ayse Gul; Nural, Ozan Ekin; Ertunc, Ozgur

2017-11-01

Purpose of this study is to analyze the direct numerical simulation data of a turbulent boundary layer subjected to strong adverse pressure gradient through anisotropy invariant mapping. RANS simulation using the ``Elliptic Blending Model'' of Manceau and Hanjolic (2002) is also conducted for the same flow case with commercial software Star-CCM+ and comparison of the results with DNS data is done. RANS simulation captures the general trends in the velocity field but, significant deviations are found when skin friction coefficients are compared. Anisotropy invariant map of Lumley and Newman (1977) and barycentric map of Banerjee et al. (2007) are used for the analysis. Invariant mapping of the DNS data has yielded that at locations away from the wall, flow is close to one component turbulence state. In the vicinity of the wall, turbulence is at two component limit which is one border of the barycentric map and as the flow evolves along the streamwise direction, it approaches to two component turbulence state. Additionally, at the locations away from the wall, turbulence approaches to two component limit. Furthermore, analysis of the invariants of the RANS simulations shows dissimilar results. In RANS simulations invariants do not approach to any of the limit states unlike the DNS.

Gas-Liquid Packed Bed Reactors in Microgravity

NASA Technical Reports Server (NTRS)

Balakotaiah, Vemuri; Motil, Brian J.; McCready, Mark J.; Kamotani, Yasuhiro

2004-01-01

Flow regime and pressure drop data was obtained and analyzed. Pulse flow exists at lower liquid flow rates in 0-g compared to 1-g. 1-g flow regime maps do not apply in microgravity. Pressure drop is higher in microgravity (enhanced interfacial effects).

Effect of ambient pressure variation on closed loop gas system for India based Neutrino Observatory (INO)

NASA Astrophysics Data System (ADS)

Satyanarayana, B.; Majumder, G.; Mondal, N. K.; Kalmani, S. D.; Shinde, R. R.; Joshi, A.

2014-10-01

Pilot unit of a closed loop gas mixing and distribution system for the INO project was designed and is being operated with 1.8meters × 1.9meters RPCs for about two years. A number of studies on controlling the flow and optimisation of the gas mixture through the RPC stack were carried out during this period. The gas system essentially measures and attempts to maintain absolute pressure inside the RPC gas volume. During typical Mumbai monsoon seasons, the barometric pressure changes rather rapidly, due to which the gas system fails to maintain the set differential pressure between the ambience and the RPC gas volume. As the safety bubblers on the RPC gas input lines are set to work on fixed pressure differentials, the ambient pressure changes lead to either venting out and thus wasting gas through safety bubblers or over pressuring the RPCs gas volume and thus degrading its performance. The above problem also leads to gas mixture contamination through minute leaks in gas gap. The problem stated above was solved by including the ambient barometric pressure as an input parameter in the closed loop. Using this, it is now possible to maintain any set differential pressure between the ambience and RPC gas volumes between 0 to 20mm of water column, thus always ensuring a positive pressure inside the RPC gas volume with respect to the ambience. This has resulted in improved performance of the gas system by maintaining the constant gas flow and reducing the gas toping up frequency. In this paper, we will highlight the design features and improvements of the closed loop gas system. We will present some of the performance studies and considerations for scaling up the system to be used with the engineering module and then followed by Iron Calorimeter detector (ICAL), which is designed to deploy about 30,000 RPCs of 1.8meters × 1.9 meters in area.

Satellite Earth observation data to identify anthropogenic pressures in selected protected areas

NASA Astrophysics Data System (ADS)

Nagendra, Harini; Mairota, Paola; Marangi, Carmela; Lucas, Richard; Dimopoulos, Panayotis; Honrado, João Pradinho; Niphadkar, Madhura; Mücher, Caspar A.; Tomaselli, Valeria; Panitsa, Maria; Tarantino, Cristina; Manakos, Ioannis; Blonda, Palma

2015-05-01

Protected areas are experiencing increased levels of human pressure. To enable appropriate conservation action, it is critical to map and monitor changes in the type and extent of land cover/use and habitat classes, which can be related to human pressures over time. Satellite Earth observation (EO) data and techniques offer the opportunity to detect such changes. Yet association with field information and expert interpretation by ecologists is required to interpret, qualify and link these changes to human pressure. There is thus an urgent need to harmonize the technical background of experts in the field of EO data analysis with the terminology of ecologists, protected area management authorities and policy makers in order to provide meaningful, context-specific value-added EO products. This paper builds on the DPSIR framework, providing a terminology to relate the concepts of state, pressures, and drivers with the application of EO analysis. The type of pressure can be inferred through the detection of changes in state (i.e. changes in land cover and/or habitat type and/or condition). Four broad categories of changes in state are identified, i.e. land cover/habitat conversion, land cover/habitat modification, habitat fragmentation and changes in landscape connectivity, and changes in plant community structure. These categories of change in state can be mapped through EO analyses, with the goal of using expert judgement to relate changes in state to causal direct anthropogenic pressures. Drawing on expert knowledge, a set of protected areas located in diverse socio-ecological contexts and subject to a variety of pressures are analysed to (a) link the four categories of changes in state of land cover/habitats to the drivers (anthropogenic pressure), as relevant to specific target land cover and habitat classes; (b) identify (for pressure mapping) the most appropriate spatial and temporal EO data sources as well as interpretations from ecologists and field data useful in connection with EO data analysis. We provide detailed examples for two protected areas, demonstrating the use of EO data for detection of land cover/habitat change, coupled with expert interpretation to relate such change to specific anthropogenic pressures. We conclude with a discussion of the limitations and feasibility of using EO data and techniques to identify anthropogenic pressures, suggesting additional research efforts required in this direction.

Genomic rearrangements and signatures of breeding in the allo-octoploid strawberry as revealed through an allele dose based SSR linkage map

PubMed Central

2014-01-01

Background Breeders in the allo-octoploid strawberry currently make little use of molecular marker tools. As a first step of a QTL discovery project on fruit quality traits and resistance to soil-borne pathogens such as Phytophthora cactorum and Verticillium we built a genome-wide SSR linkage map for the cross Holiday x Korona. We used the previously published MADCE method to obtain full haplotype information for both of the parental cultivars, facilitating in-depth studies on their genomic organisation. Results The linkage map incorporates 508 segregating loci and represents each of the 28 chromosome pairs of octoploid strawberry, spanning an estimated length of 2050 cM. The sub-genomes are denoted according to their sequence divergence from F. vesca as revealed by marker performance. The map revealed high overall synteny between the sub-genomes, but also revealed two large inversions on LG2C and LG2D, of which the latter was confirmed using a separate mapping population. We discovered interesting breeding features within the parental cultivars by in-depth analysis of our haplotype data. The linkage map-derived homozygosity level of Holiday was similar to the pedigree-derived inbreeding level (33% and 29%, respectively). For Korona we found that the observed homozygosity level was over three times higher than expected from the pedigree (13% versus 3.6%). This could indicate selection pressure on genes that have favourable effects in homozygous states. The level of kinship between Holiday and Korona derived from our linkage map was 2.5 times higher than the pedigree-derived value. This large difference could be evidence of selection pressure enacted by strawberry breeders towards specific haplotypes. Conclusion The obtained SSR linkage map provides a good base for QTL discovery. It also provides the first biologically relevant basis for the discernment and notation of sub-genomes. For the first time, we revealed genomic rearrangements that were verified in a separate mapping population. We believe that haplotype information will become increasingly important in identifying marker-trait relationships and regions that are under selection pressure within breeding material. Our attempt at providing a biological basis for the discernment of sub-genomes warrants follow-up studies to streamline the naming of the sub-genomes among different octoploid strawberry maps. PMID:24581289

Genomic rearrangements and signatures of breeding in the allo-octoploid strawberry as revealed through an allele dose based SSR linkage map.

PubMed

van Dijk, Thijs; Pagliarani, Giulia; Pikunova, Anna; Noordijk, Yolanda; Yilmaz-Temel, Hulya; Meulenbroek, Bert; Visser, Richard G F; van de Weg, Eric

2014-03-01

Breeders in the allo-octoploid strawberry currently make little use of molecular marker tools. As a first step of a QTL discovery project on fruit quality traits and resistance to soil-borne pathogens such as Phytophthora cactorum and Verticillium we built a genome-wide SSR linkage map for the cross Holiday x Korona. We used the previously published MADCE method to obtain full haplotype information for both of the parental cultivars, facilitating in-depth studies on their genomic organisation. The linkage map incorporates 508 segregating loci and represents each of the 28 chromosome pairs of octoploid strawberry, spanning an estimated length of 2050 cM. The sub-genomes are denoted according to their sequence divergence from F. vesca as revealed by marker performance. The map revealed high overall synteny between the sub-genomes, but also revealed two large inversions on LG2C and LG2D, of which the latter was confirmed using a separate mapping population. We discovered interesting breeding features within the parental cultivars by in-depth analysis of our haplotype data. The linkage map-derived homozygosity level of Holiday was similar to the pedigree-derived inbreeding level (33% and 29%, respectively). For Korona we found that the observed homozygosity level was over three times higher than expected from the pedigree (13% versus 3.6%). This could indicate selection pressure on genes that have favourable effects in homozygous states. The level of kinship between Holiday and Korona derived from our linkage map was 2.5 times higher than the pedigree-derived value. This large difference could be evidence of selection pressure enacted by strawberry breeders towards specific haplotypes. The obtained SSR linkage map provides a good base for QTL discovery. It also provides the first biologically relevant basis for the discernment and notation of sub-genomes. For the first time, we revealed genomic rearrangements that were verified in a separate mapping population. We believe that haplotype information will become increasingly important in identifying marker-trait relationships and regions that are under selection pressure within breeding material. Our attempt at providing a biological basis for the discernment of sub-genomes warrants follow-up studies to streamline the naming of the sub-genomes among different octoploid strawberry maps.

ULF/VLF (0.001 to 50 Hz) Seismo-Acoustic Noise in the Ocean. Proceedings of a Workshop Held at Austin, Texas on November 29-December 1, 1988

DTIC Science & Technology

1989-08-03

holes drilled in the seafloor from the D/V JOIDES Resolution through petrological , geochemical and paleomagnetic studies of the samples and logging...seismome- ters and/or hydrophones (or differential pressure gauges , DPG). Testing of the new instruments at very early stages is important to ensure...resolved using ocean bottom seismometers, suspended hydrophones and differential pressure gauges assisted by an orbiting radar altimeter (GEOSAT

Restrike Particle Beam Experiments on a Dense Plasma Focus.

DTIC Science & Technology

1980-11-30

differentially pumped drift tube as shown in Figure 1. However, even the lOI of gas pressure in the drift space is sufficient to establish an equilibrium...pumped drift tube concept are five-fold: 1) Lower energy attenuation of the beam by neutral gas 2) Lower lateral spread of the beam caused by multiple...relatively low gas pressure through the use of a differentially pumped drift tube . The path makes it possible to observe ion energies to considerably lower

Control of differential strain during heating and cooling of mixed conducting metal oxide membranes

DOEpatents

Carolan, Michael Francis

2007-12-25

Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side and a permeate side, which method comprises controlling the differential strain between the oxidant feed side and the permeate side by varying either or both of the oxygen partial pressure and the total gas pressure on either or both of the oxidant feed side and the permeate side of the membrane while changing the temperature of the membrane from a first temperature to a second temperature.

BPS sectors of the Skyrme model and their non-BPS extensions

NASA Astrophysics Data System (ADS)

Adam, C.; Foster, D.; Krusch, S.; Wereszczynski, A.

2018-02-01

Two recently found coupled Bogomol'nyi-Prasad-Sommerfield (BPS) submodels of the Skyrme model are further analyzed. First, we provide a geometrical formulation of the submodels in terms of the eigenvalues of the strain tensor. Second, we study their thermodynamical properties and show that the mean-field equations of state coincide at high pressure and read p =ρ ¯/3 . We also provide evidence that matter described by the first BPS submodel has some similarity with a Bose-Einstein condensate. Moreover, we show that extending the second submodel to a non-BPS model by including certain additional terms of the full Skyrme model does not spoil the respective ansatz, leading to an ordinary differential equation for the profile of the Skymion, for any value of the topological charge. This allows for an almost analytical description of the properties of Skyrmions in this model. In particular, we analytically study the breaking and restoration of the BPS property. Finally, we provide an explanation of the success of the rational map ansatz.

A Whole-Tumor Histogram Analysis of Apparent Diffusion Coefficient Maps for Differentiating Thymic Carcinoma from Lymphoma.

PubMed

Zhang, Wei; Zhou, Yue; Xu, Xiao-Quan; Kong, Ling-Yan; Xu, Hai; Yu, Tong-Fu; Shi, Hai-Bin; Feng, Qing

2018-01-01

To assess the performance of a whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating thymic carcinoma from lymphoma, and compare it with that of a commonly used hot-spot region-of-interest (ROI)-based ADC measurement. Diffusion weighted imaging data of 15 patients with thymic carcinoma and 13 patients with lymphoma were retrospectively collected and processed with a mono-exponential model. ADC measurements were performed by using a histogram-based and hot-spot-ROI-based approach. In the histogram-based approach, the following parameters were generated: mean ADC (ADC mean ), median ADC (ADC median ), 10th and 90th percentile of ADC (ADC 10 and ADC 90 ), kurtosis, and skewness. The difference in ADCs between thymic carcinoma and lymphoma was compared using a t test. Receiver operating characteristic analyses were conducted to determine and compare the differentiating performance of ADCs. Lymphoma demonstrated significantly lower ADC mean , ADC median , ADC 10 , ADC 90 , and hot-spot-ROI-based mean ADC than those found in thymic carcinoma (all p values < 0.05). There were no differences found in the kurtosis ( p = 0.412) and skewness ( p = 0.273). The ADC 10 demonstrated optimal differentiating performance (cut-off value, 0.403 × 10 -3 mm 2 /s; area under the receiver operating characteristic curve [AUC], 0.977; sensitivity, 92.3%; specificity, 93.3%), followed by the ADC mean , ADC median , ADC 90 , and hot-spot-ROI-based mean ADC. The AUC of ADC 10 was significantly higher than that of the hot spot ROI based ADC (0.977 vs. 0.797, p = 0.036). Compared with the commonly used hot spot ROI based ADC measurement, a histogram analysis of ADC maps can improve the differentiating performance between thymic carcinoma and lymphoma.

Radiological indeterminate vestibular schwannoma and meningioma in cerebellopontine angle area: differentiating using whole-tumor histogram analysis of apparent diffusion coefficient.

PubMed

Xu, Xiao-Quan; Li, Yan; Hong, Xun-Ning; Wu, Fei-Yun; Shi, Hai-Bin

2017-02-01

To assess the role of whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating radiological indeterminate vestibular schwannoma (VS) from meningioma in cerebellopontine angle (CPA). Diffusion-weighted (DW) images (b = 0 and 1000 s/mm 2 ) of pathologically confirmed and radiological indeterminate CPA meningioma (CPAM) (n = 27) and VS (n = 12) were retrospectively collected and processed with mono-exponential model. Whole-tumor regions of interest were drawn on all slices of the ADC maps to obtain histogram parameters, including the mean ADC (ADC mean ), median ADC (ADC median ), 10th/25th/75th/90th percentile ADC (ADC 10 , ADC 25 , ADC 75 and ADC 90 ), skewness and kurtosis. The differences of ADC histogram parameters between CPAM and VS were compared using unpaired t-test. Multiple receiver operating characteristic (ROC) curves analysis was used to determine and compare the diagnostic value of each significant parameter. Significant differences were found on the ADC mean , ADC median , ADC 10 , ADC 25 , ADC 75 and ADC 90 between CPAM and VS (all p values < 0.001), while no significant difference was found on kurtosis (p = 0.562) and skewness (p = 0.047). ROC curves analysis revealed, a cut-off value of 1.126 × 10 -3 mm 2 /s for the ADC 90 value generated highest area under curves (AUC) for differentiating CPAM from VS (AUC, 0.975; sensitivity, 100%; specificity, 88.9%). Histogram analysis of ADC maps based on whole tumor can be a useful tool for differentiating radiological indeterminate CPAM from VS. The ADC 90 value was the most promising parameter for differentiating these two entities.

The Iron Law of Hierarchy? Institutional Differentiation in UK Higher Education

ERIC Educational Resources Information Center

Croxford, Linda; Raffe, David

2015-01-01

This paper maps the main dimensions of differentiation among institutions and "faculties" (subject areas within institutions) of higher education in the United Kingdom. It does so through a principal components analysis based on the characteristics of applicants and entrants. A single status dimension accounts for a quarter of the…

Applications of Differential Geometry to Cartography

ERIC Educational Resources Information Center

Benitez, Julio; Thome, Nestor

2004-01-01

This work introduces an application of differential geometry to cartography. The mathematical aspects of some geographical projections of Earth surface are revealed together with some of its more important properties. An important problem since the discovery of the 'spherical' form of the Earth is how to compose a reliable map of the surface of…

The Streaming Potential Generated by Flow of Wet Steam in Capillary Tubes

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

Marsden, S.S. Jr.; Tyran, Craig K.

1986-01-21

For a constant pressure differential, the flow of wet steam generated electric potentials which increased with time and did not reach equilibrium values. These potentials were found to increase to values greater than 100 volts. The reason for this kind of potential build-up behavior was the presence of tiny flowing water slugs which were interspersed with electrically nonconductive steam vapor slugs. The measured electric potential for wet steam increased with pressure differential, but the relationship was not linear. The increase in potential with pressure drop was attributed both to an increase in fluid flow rate and changes in the wetmore » steam quality.« less

Flowrate testing of the bag filter LANCS-BOP 6CPVC-1.5-2SPVC (LANCS Industries) at 1 psig

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

Moore, Murray E.; Currie, Karissa Lyn; Berg, Charlotte Katherine

2016-09-13

The air flowrate through a flexible HEPA grade filter (Part LANCS-BOP 6CPVC-1.5-2SPVC www.lancsindustries.com) was measured at 48 ALPM for a differential pressure drop of 1.0 psig (28 inWC, 7.0 kPa). These filters are rated by the manufacturer to have a flowrate of 3 ALPM at a differential pressure drop of 1 inWC (0.25 kPa). The Los Alamos National Laboratory Aerosol Engineering Facility used one of their test rigs (originally developed to measure the pressure drop in capsule HEPA filters) to measure the airflow through the LANCS bag filter.

Rugged switch responds to minute pressure differentials

NASA Technical Reports Server (NTRS)

Friend, L. C.; Shaub, K. D.

1967-01-01

Pressure responsive switching device exhibits high sensitivity but is extremely rugged and resistant to large amplitude shock and velocity loading. This snap-action, single pole-double throw switch operates over a wide temperature range.

Common pressure vessel battery performance

NASA Technical Reports Server (NTRS)

Otzinger, B.

1978-01-01

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

Determinants of elevated pulse pressure in middle-aged and older subjects with uncomplicated systolic hypertension: the role of proximal aortic diameter and the aortic pressure-flow relationship.

PubMed

Mitchell, Gary F; Lacourcière, Yves; Ouellet, Jean-Pascal; Izzo, Joseph L; Neutel, Joel; Kerwin, Linda J; Block, Alan J; Pfeffer, Marc A

2003-09-30

Elevated pulse pressure (PP) is associated with increased cardiovascular risk and is thought to be secondary to elastin fragmentation with secondary collagen deposition and stiffening of the aortic wall, leading to a dilated, noncompliant vasculature. By use of calibrated tonometry and pulsed Doppler, arterial stiffness and pulsatile hemodynamics were assessed in 128 subjects with uncomplicated systolic hypertension (supine systolic pressure > or =140 mm Hg off medication) and 30 normotensive control subjects of comparable age and gender. Pulse-wave velocity was assessed from tonometry and body surface measurements. Characteristic impedance (Zc) was calculated from the ratio of change in carotid pressure and aortic flow in early systole. Effective aortic diameter was assessed by use of the water hammer equation. Hypertensives were heavier (P<0.001) and had higher PP (P<0.001), which was attributable primarily to higher Zc (P<0.001), especially in women. Pulse-wave velocity was higher in hypertensives (P=0.001); however, this difference was not significant after adjustment for differences in mean arterial pressure (MAP) (P>0.153), whereas increased Zc remained highly significant (P<0.001). Increased Zc in women and in hypertensive men was attributable to decreased effective aortic diameter, with no difference in wall stiffness at comparable MAP and body weight. Elevated PP in systolic hypertension was independent of MAP and was attributable primarily to elevated Zc and reduced effective diameter of the proximal aorta. These findings are not consistent with the hypothesis of secondary aortic degeneration, dilation, and wall stiffening but rather suggest that aortic function may play an active role in the pathophysiology of systolic hypertension.

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.