Articoli di riviste: "Hydrostatic pressure"

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Bazhin, N. M., e V. N. Parmon. "Hydroosmotic pressure". Доклады Академии наук 484, n. 1 (1 maggio 2019): 52–55. http://dx.doi.org/10.31857/s0869-5652484152-55.

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This work proposes the term “hydroosmotic pressure” to define hydrostatic pressure emerging from an osmotic process during solvent diffusion through membranes. The usage of this term potentially clears the ambiguity of the term “osmotic pressure,” referring to the concentration of dissolved solids in a solution regardless of the existence of hydrostatic pressure. Hydroosmotic pressure is the difference between hydrostatic pressures on either side of the membrane; thus, the term “hydroosmotic pressure” allows for the most correct definition of many processes associated with osmotic phenomena.

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Burnett, J. C., J. A. Haas e M. S. Larson. "Renal interstitial pressure in mineralocorticoid escape". American Journal of Physiology-Renal Physiology 249, n. 3 (1 settembre 1985): F396—F399. http://dx.doi.org/10.1152/ajprenal.1985.249.3.f396.

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Studies were performed in normal and DOCA-treated rats to determine renal hydrostatic pressures within superficial peritubular capillaries, the vasa recta, and renal interstitium during mineralocorticoid escape to test the hypothesis that mineralocorticoid escape is associated with elevated renal interstitial hydrostatic pressure. Fractional sodium excretion was greater in the DOCA-treated rats (3.20 +/- 0.51%) compared with control rats (1.23 +/- 0.12%) with no difference in glomerular filtration rate and renal blood flow between the two groups. Superficial peritubular capillary hydrostatic pressure (13.4 +/- 0.6 vs. 8.3 +/- 0.3 mmHg), vasa recta hydrostatic pressure (13.8 +/- 0.5 vs. 9.0 +/- 0.4 mmHg), renal interstitial hydrostatic pressure (9.8 +/- 0.4 vs. 4.5 +/- 0.4 mmHg), and arterial pressure (145 +/- 6 vs. 120 +/- 7 mmHg) were greater in the DOCA-treated compared with the control rats. These studies establish that mineralocorticoid escape is characterized by high renal interstitial hydrostatic pressure.

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Riegel, J. A. "Hydrostatic pressures in glomeruli and renal vasculature of the hagfish, Eptatretus stouti". Journal of Experimental Biology 123, n. 1 (1 luglio 1986): 359–71. http://dx.doi.org/10.1242/jeb.123.1.359.

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Hydrostatic pressures in the renal vasculature of hagfish have been studied. Estimates of the blood colloid osmotic pressure (COP) have been made. In blood vessels supplying the renal corpuscles, the average hydrostatic pressure is about 1 kPa. The average hydrostatic pressure falls to a value of 0.04 kPa within the postcardinal vein efferent to the renal corpuscle. Within the glomerular capillaries the hydrostatic pressure averages 0.21 kPa. Since the blood COP averages about 1.4 kPa, it is clear that glomerular filtration in the hagfish is not underlain by the hydrostatic pressure of the arterial pulse. In some blood vessels efferent to the renal corpuscles, hydrostatic pressure may be as high as in the afferent supply. Evidence is presented that the glomerular capillaries are shunted by this high pressure vascular pathway.

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Škegro, Marko, Sven Karlović, Damir Ježek, Tomislav Bosiljkov, Mladen Brnčić, Marko Marelja e Filip Dujmić. "High Hydrostatic pressure". Hrvatski časopis za prehrambenu tehnologiju, biotehnologiju i nutricionizam 16, n. 3-4 (31 dicembre 2021): 101–8. http://dx.doi.org/10.31895/hcptbn.16.3-4.3.

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Proces obrade visokim hidrostatskim tlakom, kao netoplinski proces, se koristi za inaktivaciju mikroorganizama uz minimalnu preinaku same namirnice. Postiže se jednaki standard sigurnosti hrane kao kod toplinske pasterizacije te se zadovoljavaju zahtjevi potrošača za svježim i minimalno procesiranim proizvodima uz kraće vrijeme obrade za razliku od konvencionalnih tehnika. U novijim istraživanjima, visoki tlak se smatra zaslužnim za promjene u strukturi stanice i biopolimera u stanicama obrađivanih namirnica što rezultira boljem vezivanju vode, procesima želiranja te nastanku novih tekstura i proizvoda. Ovaj rad prezentira upotrebu visokog hidrostatskog tlaka kod procesiranja crvenog mesa i mesnih prerađevina, voća i povrća te utjecaj na mikroorganizme u namirnici. Uz pasterizaciju, proces se koristi i za ekstrakciju bioaktivnih tvari iz sirovina, uz značajno bolje prinose i kvalitetu u usporedbi s konvencionalnim metodama ekstrakcije.

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Inamoto, Ryuhei, Takenori Miyashita, Kosuke Akiyama, Terushige Mori e Nozomu Mori. "Endolymphatic sac is involved in the regulation of hydrostatic pressure of cochlear endolymph". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 297, n. 5 (novembre 2009): R1610—R1614. http://dx.doi.org/10.1152/ajpregu.00073.2009.

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To clarify the role of the endolymphatic sac (ES) in the regulation of endolymphatic pressure, the effects of isoproterenol, a β-adrenergic receptor agonist, and acetazolamide, a potent carbonic anhydrase inhibitor, both of which decrease ES direct current potential on cochlear hydrostatic pressure, were examined in guinea pigs. When isoproterenol was applied intravenously, hydrostatic pressures of cochlear endolymph and perilymph were significantly increased with no change in endocochlear potential or the hydrostatic pressure of cerebrospinal fluid. Acetazolamide produced no marked change in the hydrostatic pressure of cochlear endolymph. In ears with an obstructed ES, the action of isoproterenol on the hydrostatic pressure of cochlear endolymph and perilymph was suppressed. These results suggest that the ES may regulate the hydrostatic pressure of the endolymphatic system via the action of the agents such as catecholamines on the ES.

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Kaye, Jonathan Z., e John A. Baross. "Synchronous Effects of Temperature, Hydrostatic Pressure, and Salinity on Growth, Phospholipid Profiles, and Protein Patterns of Four Halomonas Species Isolated from Deep-Sea Hydrothermal-Vent and Sea Surface Environments". Applied and Environmental Microbiology 70, n. 10 (ottobre 2004): 6220–29. http://dx.doi.org/10.1128/aem.70.10.6220-6229.2004.

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ABSTRACT Four strains of euryhaline bacteria belonging to the genus Halomonas were tested for their response to a range of temperatures (2, 13, and 30°C), hydrostatic pressures (0.1, 7.5, 15, 25, 35, 45, and 55 MPa), and salinities (4, 11, and 17% total salts). The isolates were psychrotolerant, halophilic to moderately halophilic, and piezotolerant, growing fastest at 30°C, 0.1 MPa, and 4% total salts. Little or no growth occurred at the highest hydrostatic pressures tested, an effect that was more pronounced with decreasing temperatures. Growth curves suggested that the Halomonas strains tested would grow well in cool to warm hydrothermal-vent and associated subseafloor habitats, but poorly or not at all under cold deep-sea conditions. The intermediate salinity tested enhanced growth under certain high-hydrostatic-pressure and low-temperature conditions, highlighting a synergistic effect on growth for these combined stresses. Phospholipid profiles obtained at 30°C indicated that hydrostatic pressure exerted the dominant control on the degree of lipid saturation, although elevated salinity slightly mitigated the increased degree of lipid unsaturation caused by increased hydrostatic pressure. Profiles of cytosolic and membrane proteins of Halomonas axialensis and H. hydrothermalis performed at 30°C under various salinities and hydrostatic pressure conditions indicated several hydrostatic pressure and salinity effects, including proteins whose expression was induced by either an elevated salinity or hydrostatic pressure, but not by a combination of the two. The interplay between salinity and hydrostatic pressure on microbial growth and physiology suggests that adaptations to hydrostatic pressure and possibly other stresses may partially explain the euryhaline phenotype of members of the genus Halomonas living in deep-sea environments.

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Harte, Federico M., Subba Rao Gurram, Lloyd O. Luedecke, Barry G. Swanson e Gustavo V. Barbosa-Cánovas. "Effect of high hydrostatic pressure and whey proteins on the disruption of casein micelle isolates". Journal of Dairy Research 74, n. 4 (26 ottobre 2007): 452–58. http://dx.doi.org/10.1017/s0022029907002762.

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High hydrostatic pressure disruption of casein micelle isolates was studied by analytical ultracentrifugation and transmission electron microscopy. Casein micelles were isolated from skim milk and subjected to combinations of thermal treatment (85°C, 20 min) and high hydrostatic pressure (up to 676 MPa) with and without whey protein added. High hydrostatic pressure promoted extensive disruption of the casein micelles in the 250 to 310 MPa pressure range. At pressures greater than 310 MPa no further disruption was observed. The addition of whey protein to casein micelle isolates protected the micelles from high hydrostatic pressure induced disruption only when the mix was thermally processed before pressure treatment. The more whey protein was added (up to 5 g/l) the more the protection against high hydrostatic pressure induced micelle disruption was observed in thermally treated samples subjected to 310 MPa.

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Mahmood, Rabeea, Anwer Mhannawee e Esraa Mohsen. "Effect of hydrostatic pressure on some quality properties in Iraqi rams and calves’ meats". Bionatura 8, n. 4 (15 dicembre 2023): 1–9. http://dx.doi.org/10.21931/rb/2023.08.04.74.

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Two experiments have been conducted in this research to determine the effects of hydrostatic pressure on Iraqi rams and calves’ meats. (One experiment for each kind of meat), Four treatments were designed for each experiment: control with no hydrostatic pressure, T1 with 100 bar exposed pressure, T2 with 200 bar and T3 with 300 bar. The pressures were generated and handled via a device designed and manufactured for this goal. The studied properties were water holding capacity WHC, thaw loss, fragmentation index FI, myofibril fragmentation index MFI, protein solubility and shear force. All these properties are strongly related to meat tenderness. All studied properties were affected significantly by applying hydrostatic pressure on meat samples to rams and calves’ meat samples. Therefore, exposing the meat to hydrostatic pressure enhances its tenderness-related properties. Keywords: hydrostatic pressure; tenderness; Protein solubility.

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Liu, Huanqiang, Xueqing Yang, Linhua Jiang, Keliang Li e Weizhun Jin. "Effects of Hydrostatic Pressure and Cation Type on the Chloride Ion Transport Rate in Marine Concrete: An Experimental Study". Materials 17, n. 13 (29 giugno 2024): 3195. http://dx.doi.org/10.3390/ma17133195.

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The effect of hydrostatic pressure and cation type on chloride ion transport in marine underwater concrete cannot be ignored. The study of the chloride ion transport behavior of concrete under the effect of hydrostatic pressure and cation type coupling can provide a basis for durability design and the protection of marine concrete. In this work, the chloride ion transport behavior of marine concrete in four common chloride salt solutions under different hydrostatic pressures is studied by a hydrostatic pressure test device developed by the authors. The results show that hydrostatic pressure and its action time significantly influence the chloride ion transport behavior in marine concrete; the higher the hydrostatic pressure of concrete, the faster the chloride ion transport rate. The longer the time, the more chloride ions accumulated in the same position, and the farther the chloride ion transport distance. Cation type has a certain influence on the transport process of chloride ions. Under the same test conditions, the chloride ion transport rate in a divalent cation solution is about 5% higher than that in a monovalent cation solution. The results also show that the chloride ion binding capacity under hydrostatic pressure is only 10~20% of that under natural diffusion. Using the test results, a predictive model of a chloride ion apparent transport coefficient based on the hydrostatic pressure and hydrostatic pressure action time corrected by a cation type influence coefficient is established.

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Tamošiūnas, Tadas, e Šarūnas Skuodis. "Non-cohesive Soil Direct Shear Strength Affected with Hydrostatic Pressure". Mokslas - Lietuvos ateitis 9, n. 5 (27 dicembre 2017): 520–23. http://dx.doi.org/10.3846/mla.2017.1078.

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This paper presents first results of noncohesive soil direct shear tests with hydrostatic pressure. To reach this aim, it was chosen the Baltic Sea Klaipėda sand, due to granulometry composition and particles shape. According to this, investigated Baltic Sea sand can be called Lithuanian standard sand for scientific testing. Analysis of results revealed, that when it is increased hydrostatic pressure, the shearing strength is also increasing. Comparing air dry sand results with fully saturated sand and affected with 100 kPa of hydrostatic pressure, the angle of internal friction increased for 21,24%. Meanwhile, the cohesion was not changing so dramatically according to hydrostatic pressure change. Obtained results allows to proceed this research work more detailed with different loading types, testing procedures and hydrostatic pressures.

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NÚÑEZ-REGUEIRO, MANUEL. "C60 UNDER PRESSURE". Modern Physics Letters B 06, n. 19 (20 agosto 1992): 1153–58. http://dx.doi.org/10.1142/s0217984992002039.

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The high pressure experiments done on fullerenes are reviewed. C 60 has found to be stable up to about 20 GPa at room temperature and hydrostatic conditions. Application of stronger, or non-hydrostatic, pressures at room temperature can induce the formation of a partially sp3 bonded phase, that apparently conserves the fullerene cage. Extreme non-hydrostatic compressions above about 15 GPa can, though, break down the cage and produce amorphous or cubic diamond. Destruction of the cage at high temperatures has also been observed, but the resulting product is amorphous sp2 material. A preliminary pressure-temperature phase diagram for C 60 is proposed.

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Hu, Guangcai, Guangning Wu, Rui Yu, Peng Zhou, Bo Gao, Yan Yang e Kai Liu. "The Influence of Pressure on the Discharge along Oil-Paper Interface under AC Stress". Energies 12, n. 10 (15 maggio 2019): 1846. http://dx.doi.org/10.3390/en12101846.

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This study explores the influence of hydrostatic pressure on the discharge along the oil-paper interface under AC voltage, especially for the normal operating condition and breakdown. In this paper, an experimental platform was set up to record the partial discharge (PD) parameters of the test sample under different hydrostatic pressures, while the applied AC voltage was increased to final flashover voltage step by step. Experimental results showed that higher hydrostatic pressure had different effects on PD under different voltages. Higher pressure decreased the PD energy and increased the flashover voltage. Furthermore, under higher hydrostatic pressure, discharge traces (white mark) were found on the surface of the samples after intense discharging on the oil-paper interfaces, indicating that the hydrostatic pressure can affect the gas generation and dissipation process underneath the surface of the pressboards. Finally, the mechanism of how hydrostatic pressure influences the PD, flashover voltage, and white mark was interpreted based on the bubble theory. The results derived in this paper can be helpful for an optimal design and reasonable operation of oil-paper insulation systems, especially for power transformers.

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Yan, Dong, Decun Bian, Jinchang Zhao e Shaoqing Niu. "Study of the Electrical Characteristics, Shock-Wave Pressure Characteristics, and Attenuation Law Based on Pulse Discharge in Water". Shock and Vibration 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/6412309.

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Strong shock waves can be generated by pulse discharge in water. Study of the pressure characteristics and attenuation law of these waves is highly significant to industrial production and national defense construction. In this research, the shock-wave pressures at several sites were measured by experiment under different conditions of hydrostatic pressure, discharge energy, and propagation distance. Moreover, the shock-wave pressure characteristics were analyzed by combining them with the discharge characteristics in water. An attenuation equation for a shock wave as a function of discharge energy, hydrostatic pressure, and propagation distance was fitted. The experimental results indicated that (1) an increase in hydrostatic pressure had an inhibiting effect on discharge breakdown; (2) the shock-wave peak pressure increased with increasing discharge voltage at 0.5 m from the electrode; it increased rapidly at first and then decreased slowly with increasing hydrostatic pressure; and (3) shock-wave attenuation slowed down with increasing breakdown energy and hydrostatic pressure during shock-wave transfer. These experimental results were discussed based on the mechanism described.

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Feng, Chaoqun, Pei Zhang, Chengshun Xu e Xiuli Du. "Influence of the initial hydrostatic pressure on contact area coefficient under drainage condition". E3S Web of Conferences 276 (2021): 01023. http://dx.doi.org/10.1051/e3sconf/202127601023.

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The expression of effective stress proposed by Terzaghi has always been questioned. Many correction formulas are modification of pore pressure term. The pore pressure factor is related to porosity, contact area and other factors. When the particles are in point contact, the expression of the effective stress is that proposed by Terzaghi, while for the surface contact particles, the actual effective stress increases the stress produced by pore pressure passing through the contact surface based on the Terzaghi effective stress. There are many factors that affect the development of contact area and pore pressure, therefore, a series of the drained triaxial tests were carried out on four groups of sand samples with different initial hydrostatic pressures to study the influence of different initial hydrostatic pressures on the effective stress due to the term of contact area (σα). The test results show that the shear strength is increases with the initial hydrostatic pressure under the same effective confining pressure, which indirectly indicates that the initial hydrostatic pressure increases the contact area stress.

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Yoshino, Masahiko, Yasufumi Ogawa e Sivanandam Aravindan. "Machining of Hard-Brittle Materials by a Single Point Tool Under External Hydrostatic Pressure". Journal of Manufacturing Science and Engineering 127, n. 4 (10 febbraio 2005): 837–45. http://dx.doi.org/10.1115/1.2035695.

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This paper reports on the development of a machining device which is capable of carrying out precision machining experiments under external hydrostatic pressure. Machining trials were conducted on hard-brittle materials such as soda glass, quartz glass, silicon and quartz wafers using the newly developed machining device under the externally applied hydrostatic pressures of zero and 400 MPa. The machined traces were analyzed by laser microscope. From the trace profiles, crack ratio and area of cross section of the trace were estimated. The applied hydrostatic pressure enhanced the critical cross sectional area and reduced the cracks and chippings of all the tested materials. Effects of hydrostatic pressure on the machining characteristics of the crystalline and glassy materials are discussed in detail. The mechanism behind the enhancement of ductile-brittle transition by the externally applied hydrostatic pressure is also elucidated by a theoretical model.

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Wirkert, Florian J., Michael Paulus, Julia Nase, Johannes Möller, Simon Kujawski, Christian Sternemann e Metin Tolan. "X-ray reflectivity measurements of liquid/solid interfaces under high hydrostatic pressure conditions". Journal of Synchrotron Radiation 21, n. 1 (2 novembre 2013): 76–81. http://dx.doi.org/10.1107/s1600577513021516.

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A high-pressure cell forin situX-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for thein situinvestigation of adsorption phenomena in biological systems.

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Heinz, Viktor, Niklas Pilz, Tomas Lucca Bothe e Andreas Patzak. "ENHANCING NOCTURNAL BLOOD PRESSURE ASSESSMENT THROUGH HYDROSTATIC PRESSURE CORRECTION: A CLINICAL STUDY". Journal of Hypertension 42, Suppl 1 (maggio 2024): e82. http://dx.doi.org/10.1097/01.hjh.0001020080.37410.e9.

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Objective: The evaluation of nocturnal blood pressure (BP) and corresponding dipping patterns is pivotal in understanding and managing arterial hypertension and cardiovascular health. However, poor reproducibility in determining dipping patterns is attributed to sleep-related positional changes and resultant variations in hydrostatic pressure. This study aimed to delve into the impact of hydrostatic pressure on nocturnal BP assessment and considering its clinical relevance. Design and method: 52 subjects (26 aged 18-30 and 26 aged 50 or older) underwent nocturnal oscillometric BP measurements. The hydrostatic pressure difference between the heart and the BP cuff as well as the current body position was continuously monitored. Results: The study's results revealed a strong effect of correcting hydrostatic pressure differences between the cuff and the heart level on the nocturnal mean BP levels and dipping patterns. The mean nocturnal BP and the change in dipping pattern correlated strongly with the size of hydrostatic effects. Combining biometrical data with body position measurements allowed to partly estimate the direction and amplitude of hydrostatic effects on single measurements. Conclusions: This study underscores the influence of hydrostatic pressure variations on nocturnal BP assessment and dipping patterns. Our findings highlight the necessity of correcting for hydrostatic pressure differences between the heart level and the cuff, especially during the night while sleep-related positional changes might occur. Integrating biometric data and body position monitoring into nocturnal BP measurement protocols might pave the way for more accurate BP assessments and personalized hypertension management, catering to individual patient characteristics.

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Gerasymov, Oleg I., e Liudmyla M. Sidletska. "Hydrostatic pressure in granular environment". Environmental safety and natural resources 42, n. 2 (28 giugno 2022): 86–95. http://dx.doi.org/10.32347/2411-4049.2022.2.86-95.

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The problem is that to date there is no general theory of the granular state of matter in a closed form. However, there are some well-developed models that use, for example, the representation of a continuous environment. Typical bulk material is a large conglomeration of micro-mechanical particles of different sizes and shapes that interact with each other and the walls contain containers by mainly repulsive forces in direct mechanical contact (by nature it is forces of electromagnetic origin – dry and viscous friction forces, as well as traction).In the proposed work to study the pressure in a multiparticle micro-mechanical system, a model of a lattice gas in a gravitational field is considered. Analysis of the determination of free energy and entropy allowed us to establish the corresponding equilibrium density profile, which is described by a Fermi-type function. The Fermi profile in the form of a density field was used to find the vertical hydrostatic pressure for which the analytical expression was obtained. Hydrostatic pressure was different from the known relations derived from the theory of condensed matter. The obtained results are confirmed by experimental observations, which indicate a complex, anisotropic significantly different from the known from the theory of condensed matter distribution of even vertical pressure in large conglomerations of discrete micro-mechanical particles. Which really repeats the Fermi distribution. The obtained results stimulate the revision of typical ratios of hydrostatics of continuous media, such as Pascal's laws. Torricelli, Archimedes and Bernoulli in the case of discrete micro-mechanical (granular) systems. The conclusions of the work can be significant in the design and evaluation of operating parameters of storage, release and transportation of bulk cargo, which consist of discrete micro-mechanical conglomerations with different degrees of compaction and compaction.

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Loring, S. H., K. Yoshino, W. R. Kimball e G. M. Barnas. "Gravitational and shear-associated pressure gradients in the abdomen". Journal of Applied Physiology 77, n. 3 (1 settembre 1994): 1375–82. http://dx.doi.org/10.1152/jappl.1994.77.3.1375.

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The abdomen has been variously characterized as a hydrostatic system, in which pressures exhibit a gravitational gradient and pressure fluctuations are spatially uniform, and as a compartment, in which pressure gradients are not simply gravitational and pressure fluctuations differ markedly from place to place. To characterize the pressures acting on the ventral abdominal wall, we used saline-filled catheters and air-filled balloons in anesthetized dogs in various body positions during spontaneous breathing and mechanical ventilation. Pressures were measured in the stomach and at multiple sites next to the abdominal wall. Under most circumstances, measurements next to the abdominal wall exhibited a hydrostatic gravitational gradient of approximately 0.89 cmH2O/cm height and pressure fluctuations were spatially homogeneous. Deviations from this hydrostatic behavior were seen when abdominal pressures were compared with gastric pressures, when measurements were made with a balloon catheter, and when the lower abdomen was constricted with a binder. Analysis of these and previously published data suggests that the abdomen does, at times, behave like a hydraulic system but can deviate from simple hydrostatic behavior to the extent that shape-stable abdominal viscera are deformed.

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Watkins, D., H. R. Piehler, V. Seetharaman, C. M. Lombard e S. L. Semiatin. "Effect of hydrostatic pressure". Metallurgical Transactions A 23, n. 9 (settembre 1992): 2669–72. http://dx.doi.org/10.1007/bf02658071.

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Fraser, Peter J., e Alister G. Macdonald. "Crab hydrostatic pressure sensors". Nature 371, n. 6496 (settembre 1994): 383–84. http://dx.doi.org/10.1038/371383b0.

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Nihous, Gérard C. "Notes on hydrostatic pressure". Journal of Ocean Engineering and Marine Energy 2, n. 1 (2 settembre 2015): 105–9. http://dx.doi.org/10.1007/s40722-015-0035-1.

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Tar, Balázs, András Ágoston, Áron Üveges, Gábor Tamás Szabó, Tibor Szűk, András Komócsi, Dániel Czuriga, Benjamin Csippa, György Paál e Zsolt Kőszegi. "Pressure- and 3D-Derived Coronary Flow Reserve with Hydrostatic Pressure Correction: Comparison with Intracoronary Doppler Measurements". Journal of Personalized Medicine 12, n. 5 (12 maggio 2022): 780. http://dx.doi.org/10.3390/jpm12050780.

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Purpose: To develop a method of coronary flow reserve (CFR) calculation derived from three-dimensional (3D) coronary angiographic parameters and intracoronary pressure data during fractional flow reserve (FFR) measurement. Methods: Altogether 19 coronary arteries of 16 native and 3 stented vessels were reconstructed in 3D. The measured distal intracoronary pressures were corrected to the hydrostatic pressure based on the height differences between the levels of the vessel orifice and the sensor position. Classical fluid dynamic equations were applied to calculate the flow during the resting state and vasodilatation based on morphological data and intracoronary pressure values. 3D-derived coronary flow reserve (CFRp-3D) was defined as the ratio between the calculated hyperemic and the resting flow and was compared to the CFR values simultaneously measured by the Doppler sensor (CFRDoppler). Results: Haemodynamic calculations using the distal coronary pressures corrected for hydrostatic pressures showed a strong correlation between the individual CFRp-3D values and the CFRDoppler measurements (r = 0.89, p < 0.0001). Hydrostatic pressure correction increased the specificity of the method from 46.1% to 92.3% for predicting an abnormal CFRDoppler < 2. Conclusions: CFRp-3D calculation with hydrostatic pressure correction during FFR measurement facilitates a comprehensive hemodynamic assessment, supporting the complex evaluation of macro-and microvascular coronary artery disease.

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Munro, Catriona, James P. Morris, Alastair Brown, Chris Hauton e Sven Thatje. "The role of ontogeny in physiological tolerance: decreasing hydrostatic pressure tolerance with development in the northern stone crab Lithodes maja". Proceedings of the Royal Society B: Biological Sciences 282, n. 1809 (22 giugno 2015): 20150577. http://dx.doi.org/10.1098/rspb.2015.0577.

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Extant deep-sea invertebrate fauna represent both ancient and recent invasions from shallow-water habitats. Hydrostatic pressure may present a significant physiological challenge to organisms seeking to colonize deeper waters or migrate ontogenetically. Pressure may be a key factor contributing to bottlenecks in the radiation of taxa and potentially drive speciation. Here, we assess shifts in the tolerance of hydrostatic pressure through early ontogeny of the northern stone crab Lithodes maja , which occupies a depth range of 4–790 m in the North Atlantic. The zoea I, megalopa and crab I stages were exposed to hydrostatic pressures up to 30.0 MPa (equivalent of 3000 m depth), and the relative fold change of genes putatively coding for the N -methyl- d -aspartate receptor-regulated protein 1 ( narg gene), two heat-shock protein 70 kDa (HSP70) isoforms and mitochondrial Citrate Synthase ( CS gene) were measured. This study finds a significant increase in the relative expression of the CS and hsp70a genes with increased hydrostatic pressure in the zoea I stage, and an increase in the relative expression of all genes with increased hydrostatic pressure in the megalopa and crab I stages. Transcriptional responses are corroborated by patterns in respiratory rates in response to hydrostatic pressure in all stages. These results suggest a decrease in the acute high-pressure tolerance limit as ontogeny advances, as reflected by a shift in the hydrostatic pressure at which significant differences are observed.

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Leonardi, Maria Soledad, José E. Crespo, Florencia A. Soto, Ricardo B. Vera, Julio C. Rua e Claudio R. Lazzari. "Under pressure: the extraordinary survival of seal lice in the deep sea". Journal of Experimental Biology 223, n. 17 (17 luglio 2020): jeb226811. http://dx.doi.org/10.1242/jeb.226811.

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ABSTRACTLice from pinnipeds – sea lions, seals and walruses – are the only insects capable of surviving marine dives. Throughout their evolutionary history, they have adapted to tolerate hypoxia, high salinity, low temperature and, in particular, to tolerate conditions of high hydrostatic pressure. To understand the limits of the capacity of lice to survive during host deep dives, we conducted a series of controlled experiments in the laboratory. We collected lice from elephant seals and submitted the different life stages to high pressure conditions. Lice were first exposed to one of four hydrostatic pressures: 30, 80, 150 or 200 kg cm−2. They were then exposed a second time to higher or lower hydrostatic pressure conditions to test for the impact of the first experience, which could either be deleterious or trigger physiological adaption, allowing them a better tolerance to high pressure. We found that lice from elephant seals can tolerate hydrostatic pressures higher than 200 kg cm−2 (close to 200 atm), which is equivalent to 2000 m depth. Adults exhibited lower recovery times than nymphs after immersion at high hydrostatic pressure. Our findings show that lice have developed unique adaptations to endure extreme marine conditions. We discuss these extreme performances in relation to the morphological characteristics and physiological responses to diving in these insects.

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Lebedev, V. L., V. Yu Kosulnikov, P. V. Sery e S. N. Troshkin. "Acoustic emission in hydrostatic strength tests of spheroplastics". Voprosy Materialovedeniya, n. 3(115) (14 ottobre 2023): 136–46. http://dx.doi.org/10.22349/1994-6716-2023-115-3-136-146.

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Registration of acoustic emission in the process of spheroplastics destruction in a high-pressure hydrostatic chamber is realized. Hardware design does not require specialized equipment and is based on available components. Time synchronization on pressure and acoustic emission graphs ensures pressure fixation of pressures at which the formation of cracks in the spheroplastic sample begins. It is shown that accumulation of destructions begins with pressure, smaller, than pressure fixed as short-term hydrostatic durability.

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Kiyoumarsioskouei, Amir, Mohammad S. Saidi, Bobak Mosadegh e Bahar Firoozabadi. "A portable culture chamber for studying the effects of hydrostatic pressure on cellular monolayers". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, n. 3 (3 maggio 2018): 807–16. http://dx.doi.org/10.1177/0954406218766204.

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Hydrostatic pressure is one of the most fundamental and common mechanical stimuli in the body, playing a critical role in the homeostasis of all organ systems. Kidney function is affected by high blood pressure, namely hypertension, by the increased pressure acting on the glomerular capillary walls. This general effect of hypertension is diagnosed as a chronic disease, but underlying mechanistic causes are still not well understood. This paper reports a portable and adaptive device for studying the effects of hydrostatic pressure on a monolayer of cells. The fabricated device fits within a conventional incubation system and microscope. The effects of various pressures and durations were evaluated on a confluent layer of human endothelial cells. We found that a fluid pressure (i.e. hydrostatic pressure) can alter the morphology of the cells and that returning to an ambient pressure can reverse the changes in morphology. Thus, this study provides a proof-of-principle demonstration that this tool can be utilized for exploring the effects of hydrostatic pressure on mammalian cells.

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Swirad, S. "Surface texture characterization of alpha-beta titanium alloy (Ti6Al4V) after hydrostatic burnishing". MATEC Web of Conferences 189 (2018): 01001. http://dx.doi.org/10.1051/matecconf/201818901001.

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The ball burnishing process with hydrostatic tools is very economical finishing process for various types of machine parts. This process reduces the height of surface unevenness, introduces compressive stresses at high depth (approx. 1 mm) and increase the hardness of the surface layer. The paper presents effect of the ball burnishing process parameters with hydrostatic tools on the surface structure geometry of titanium alloy. This shows how the surface roughness can be reduced after preceding operation by the ball burnishing process. This process changes the surface stereometrics of the previously milled surface. Burnishing with hydrostatic tools can be easily and effectively used either on conventional or on CNC machines. The Ecoroll burnishing system used in this research consists of a high-pressure hydraulic pump (model 4.0 HGP) and the 6 mm diameter burnishing tool both connected via high-pressure hoses. The burnishing tool is based on a hydrostatics principle; the key element is a 6mm ball made of ceramics. The input process parameters considered in the paper included: burnishing rate, applied pressure and line to line pitch. It also showed a positive effect of hydrostatics burnishing on roughness and geometric structure of the surface. In most cases, the result is anisotropic surface, reduced roughness, reduced amplitude values of parameters such as: Sa, Sz. The biggest impact on the value of indicators of geometric structure comes from pressure, the smaller (but still significant) impact results from a tool speed and line to line pitch

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Moulton, N. E., S. A. Wolf, E. F. Skelton, D. H. Liebenberg, T. A. Vanderah, A. M. Hermann e H. M. Duan. "Pressure dependence ofTcinTl2Ba2CaCu2O8at hydrostatic pressures to 6 GPa". Physical Review B 44, n. 22 (1 dicembre 1991): 12632–34. http://dx.doi.org/10.1103/physrevb.44.12632.

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30

Khraibi, A. A., J. A. Haas e F. G. Knox. "Effect of renal perfusion pressure on renal interstitial hydrostatic pressure in rats". American Journal of Physiology-Renal Physiology 256, n. 1 (1 gennaio 1989): F165—F170. http://dx.doi.org/10.1152/ajprenal.1989.256.1.f165.

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The purpose of this study was to investigate the hypothesis that changes in renal perfusion pressure may be transmitted to the renal interstitium and cause alterations in renal interstitial hydrostatic pressure and sodium excretion. A method that utilizes a chronically implanted polyethylene matrix that allows for direct continuous measurement of renal interstitial hydrostatic pressure, and agrees well with subcapsular measurement in rats, was developed. Renal interstitial hydrostatic pressure, fractional excretion of sodium, and urine flow rate were 3.0 +/- 0.3 mmHg, 0.35 +/- 0.13%, and 19.44 +/- 3.00 microliter/min, respectively, when renal perfusion pressure was 101 +/- 0.8 mmHg. When renal perfusion pressure was increased to 123 +/- 0.9 mmHg renal interstitial hydrostatic pressure, fractional excretion of sodium, and urine flow rate increased significantly to 5.8 +/- 0.6 mmHg, 1.29 +/- 0.29%, and 50.76 +/- 8.83 microliter/min, respectively, in anesthetized male Sprague-Dawley rats. These changes occur despite a well-autoregulated glomerular filtration rate and renal blood flow. In conclusion, increasing renal perfusion pressure caused a significant increase in renal interstitial hydrostatic pressure as measured directly by the implanted polyethylene matrix method and was associated with a significant increase in sodium excretion.

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Finn, Michael A., Nathan D. Faulkner, Scott J. Hetzel e Paul A. Anderson. "Spinal duraplasty materials and hydrostasis: a biomechanical study". Journal of Neurosurgery: Spine 15, n. 4 (ottobre 2011): 422–27. http://dx.doi.org/10.3171/2011.5.spine10851.

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Object Dural tears are a frequent complication of spinal surgery and contribute to significant morbidity. Occasionally, dural tears cannot be closed primarily and dural patch grafts must be utilized. No data exist on the comparative immediate hydrostatic strength of various patch materials used alone or with a biological adhesive in a spinal dural tear model. Thus, the authors conducted this study to determine the comparative effectiveness of various patch materials used with and without biological adhesive. Methods Twenty-four thoracic spines from calves were prepared with laminectomies and spinal cord evacuation, leaving the dura intact. Foley catheters were inflated on either side of a planned dural defect, and baseline hydrostasis was measured using a fluid column at 30, 60, and 90 cm of H2O. A standard dural defect (1 × 2 cm) was created, and 8 patches of each material (human fascia lata, Duragen, and Preclude) were sutured in place using 5-0 Prolene hemo-seal running sutures. Hydrostasis was again tested at the same pressures. Finally, a hydrogel sealant (Duraseal) was placed over the defect and hydrostasis was again tested. Results were analyzed with repeated measures ANOVA. Results The leakage rate increased significantly at each pressure tested for all conditions. There was no difference in leakage among the 3 patch materials at any of the pressures or for either condition (with or without sealant). All patch materials allowed significantly greater leakage than the intact condition at all pressures. The use of sealant reduced leakage significantly at the 30 and 60 mm Hg pressures to levels similar to the intact condition. At 90 mm Hg, leakage of the sealed construct was greater than at the intact condition but significantly less than without the use of sealant. Conclusions All 3 dural patch materials were of similar hydrostatic strength and allowed greater leakage than at the intact condition. The use of sealant reduced the amount of leakage at all pressures compared with patching alone but allowed more leakage than the intact state at a high hydrostatic pressure (90 mm Hg).

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Müller-Marschhausen, K., J. Waschke e D. Drenckhahn. "Physiological hydrostatic pressure protects endothelial monolayer integrity". American Journal of Physiology-Cell Physiology 294, n. 1 (gennaio 2008): C324—C332. http://dx.doi.org/10.1152/ajpcell.00319.2007.

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Endothelial monolayer integrity is required to maintain endothelial barrier functions and has found to be impaired in several disorders like inflammatory edema, allergic shock, or artherosclerosis. Under physiologic conditions in vivo, endothelial cells are exposed to mechanical forces such as hydrostatic pressure, shear stress, and cyclic stretch. However, insight into the effects of hydrostatic pressure on endothelial cell biology is very limited at present. Therefore, in this study, we tested the hypothesis that physiological hydrostatic pressure protects endothelial monolayer integrity in vitro. We investigated the protective efficacy of hydrostatic pressure in microvascular myocardial endothelial (MyEnd) cells and macrovascular pulmonary artery endothelial cells (PAECs) by the application of selected pharmacological agents known to alter monolayer integrity in the absence or presence of hydrostatic pressure. In both endothelial cell lines, extracellular Ca2+ depletion by EGTA was followed by a loss of vascular-endothelial cadherin (VE-caherin) immunostaining at cell junctions. However, hydrostatic pressure (15 cmH2O) blocked this effect of EGTA. Similarly, cytochalasin D-induced actin depolymerization and intercellular gap formation and cell detachment in response to the Ca2+/calmodulin antagonist trifluperazine (TFP) as well as thrombin-induced cell dissociation were also reduced by hydrostatic pressure. Moreover, hydrostatic pressure significantly reduced the loss of VE-cadherin-mediated adhesion in response to EGTA, cytochalasin D, and TFP in MyEnd cells as determined by laser tweezer trapping using VE-cadherin-coated microbeads. In caveolin-1-deficient MyEnd cells, which lack caveolae, hydrostatic pressure did not protect monolayer integrity compromised by EGTA, indicating that caveolae-dependent mechanisms are involved in hydrostatic pressure sensing and signaling.

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Behrens, Bernd Arno, Thomas Hagen, Andreas Klassen, Julian Knigge, Jens Mielke e Insa Pfeiffer. "Forging of Aluminium Components under a Superimposed Hydrostatic Pressure to Induce Local Strain Hardening". Advanced Materials Research 137 (ottobre 2010): 191–217. http://dx.doi.org/10.4028/www.scientific.net/amr.137.191.

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A promising approach to handling low ductile aluminium alloys in a forming process is forming under superimposed hydrostatic pressure. The influence of superimposed hydrostatic pressure on the flow stress as well as on the formability for various hydrostatic pressures and temperatures was analysed [15, 3, and 7]. By increasing the formability of the workpiece, larger local plastic strains could be achieved. The results reveal highly increased formability at superimposed pressure of 85 MPa for workpieces from thermosetting alloy AlSi1MgMn (EN AW 6082) in comparison to those from self-hardening alloy AlMg4.5Mn0.7 (EN AW 5083). As a general tendency, the self-hardening alloys show a lower increase in formability when forged under superimposed pressure. But additionally, a charge-dependent influence of macro- and micro defects on the crack resistance was detected for alloy AlMg4.5Mn0.7. By evaluating damage models in finite element models the damage occurring in cold forming processes under superimposed hydrostatic pressure was predicted.

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Sapriki, Huda Hinggo, Partono Partono e M. Barkah Salim. "The Development Of Hydrostatic Pressure Props As Learning Media Physics Of Senior High School". JURNAL FIRNAS 1, n. 1 (29 maggio 2020): 1–9. http://dx.doi.org/10.24127/firnas.v1i1.1647.

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AbstractThe props used by students of SMAN 4 metro are only able to show the concept of hydrostatic pressure through spray distance only. This resulted in the limited knowledge of students regarding the concept of hydrostatic pressure.. So researchers need to develop props that are able to show the concept of hydrostatic pressure to be more complex, can show the effect of depth to the amount of pressure, can show the amount of hydrostatic pressure in the same depth, and can show the effect of density to the amount of pressure. The purpose of this research are: (1) produces hydrostatic pressure props that work well, (2) produces hydrostatic pressure props that are suitable for learning media, and (3) to know about students respond of hydrostatic pressure props developed. This research is done by research and development method (R & D) using ADDIE development model (Analysis, Design, Development, Implementation and Evaluation). The results of this research are: (1) Hydrostatic pressure props developed can work well, (2) the average of feasibility level media component and material is amount of 95.8% include of the criteria of props is very feasible to use as a media of learning., and (3) student's response to props amounted to90.96% means the props are very well received by the students. Keywords: Research and Development, Learning Media, Hydrostatic Pressure Tool

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Wang, Yiyang, Baoshuai Bai, Yanzhu Hu, Haoming Wang, Ningyuan Liu, Yibo Li, Pei Li, Guangdong Zhou e Qiang Zhou. "Hydrostatic Pressure Modulates Intervertebral Disc Cell Survival and Extracellular Matrix Homeostasis via Regulating Hippo-YAP/TAZ Pathway". Stem Cells International 2021 (16 giugno 2021): 1–17. http://dx.doi.org/10.1155/2021/5626487.

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Established studies proved that hydrostatic pressure had multiple effects on the biological behavior of the intervertebral disc (IVD). However, the conclusions of the previous studies were inconsistent, due to the difference in hydrostatic loading devices and observing methods used in these studies. The current study is aimed at investigating the role of dynamic hydrostatic pressure in regulating biological behavior of the notochordal nucleus pulposus (NP) and fibrocartilaginous inner annulus fibrosus (AF) and its possible mechanism using our novel self-developed hydrostatic pressure bioreactor. The differences in the biological behavior of the rabbit IVD tissues under different degree of hydrostatic pressure were evaluated via histological analysis. Results revealed that low-loading dynamic hydrostatic pressure was beneficial for cell survival and extracellular matrix (ECM) homeostasis in notochordal NP and fibrocartilaginous inner AF via upregulating N-cadherin (N-CDH) and integrin β1. In comparison, high-magnitude dynamic hydrostatic pressure aggravated the breakdown of ECM homeostasis in NP and inner AF via enhancing the Hippo-YAP/TAZ pathway-mediated cell apoptosis. Moreover, inner AF exhibited greater tolerance to physiological medium-loading degree of hydrostatic pressure than notochordal NP. The potential mechanism was related to the differential expression of mechanosensing factors in notochordal NP and fibrocartilaginous inner AF, which affects the fate of the cells under hydrostatic pressure. Our findings may provide a better understanding of the regulatory role of hydrostatic pressure on the cellular fate commitment and matrix metabolism of the IVD and more substantial evidence for using hydrostatic pressure bioreactor in exploring the IVD degeneration mechanism as well as regeneration strategies.

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Groothuis, Jan T., Fleur Poelkens, Constantijn W. Wouters, Miriam Kooijman e Maria T. E. Hopman. "Leg intravenous pressure during head-up tilt". Journal of Applied Physiology 105, n. 3 (settembre 2008): 811–15. http://dx.doi.org/10.1152/japplphysiol.90304.2008.

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Leg vascular resistance is calculated as the arterial-venous pressure gradient divided by blood flow. During orthostatic challenges it is assumed that the hydrostatic pressure contributes equally to leg arterial, as well as to leg venous pressure. Because of venous valves, one may question whether, during orthostatic challenges, a continuous hydrostatic column is formed and if leg venous pressure is equal to the hydrostatic pressure. The purpose of this study was, therefore, to measure intravenous pressure in the great saphenous vein of 12 healthy individuals during 30° and 70° head-up tilt and compare this with the calculated hydrostatic pressure. The height difference between the heart and the right medial malleolus level represented the hydrostatic column. The results demonstrate that there were no differences between the measured intravenous pressure and the calculated hydrostatic pressure during 30° (47.2 ± 1.0 and 46.9 ± 1.5 mmHg, respectively) and 70° head-up tilt (83.9 ± 0.9 and 85.1 ± 1.2 mmHg, respectively). Steady-state levels of intravenous pressure were reached after 95 ± 12 s during 30° and 161 ± 15 s during 70° head-up tilt. In conclusion, the measured leg venous pressure is similar to the calculated hydrostatic pressure during orthostatic challenges. Therefore, the assumption that hydrostatic pressure contributes equally to leg arterial as well as to leg venous pressure during orthostatic challenges can be made.

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Ding, Yang, Tong-Lin Yang, Hui Liu, Zhen Han, Shuang-Xi Zhou, Zhong-Ping Wang, An-Ming She, Yong-Qi Wei e Jing-Liang Dong. "Experimental Study and Simulation Calculation of the Chloride Resistance of Concrete under Multiple Factors". Applied Sciences 11, n. 12 (8 giugno 2021): 5322. http://dx.doi.org/10.3390/app11125322.

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Cement is widely used in marine concrete, and its resistance to chloride ion corrosion has been widely considered. In this paper, based on a laboratory test, the influence of different hydrostatic pressures, coarse aggregate contents and w/c ratios on the chloride resistance performance is analyzed. Based on COMSOL finite element software, a two-dimensional cementitious materials model is established, and the simulation results are compared with the experimental results. The results show that the penetration depth of chloride ions in cement increases with the increase of the w/c ratio. Under the hydrostatic pressure of 0 MPa, when the w/c ratio is 0.35, the penetration depth of chloride ions is 7.4 mm, and the simulation result is 8.0 mm. When the w/c ratio is 0.45, the penetration depth of chloride ions is 9.3 mm, and the simulation result is 9.9 mm. When the w/c ratio is 0.55, the penetration depth of chloride ions is 12.9 mm, and the simulation result is 12.1 mm. Under different hydrostatic pressures, the penetration depth of chloride ions obviously changes, and with the increase in hydrostatic pressure, the penetration depth of chloride ions deepens. Under the w/c ratio of 0.35, when the hydrostatic pressure is 0.5 MPa, the penetration depth of chloride ions is 11.3 mm, and the simulation result is 12.1 mm. When the hydrostatic pressure is 1.0 MPa, the penetration depth of chloride ions is 16.2 mm, and the simulation result is 17.5 mm.

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Khalifa, Mahmoud Osman, Chen Yan, Yong Chai, Kosei Ito, Shou-Hua Zhang e Tao-Sheng Li. "Hydrostatic pressure mediates epithelial-mesenchymal transition of cholangiocytes through RhoA/ROCK and TGF-β/smad pathways". PLOS ONE 19, n. 4 (5 aprile 2024): e0300548. http://dx.doi.org/10.1371/journal.pone.0300548.

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Biomechanical cue within the tissue microenvironment is known to play a critical role in regulating cell behaviors and maintaining tissue homeostasis. As hydrostatic pressure often increases in biliary system under pathological states, we investigated the effect of the moderate elevation of the hydrostatic pressure on biliary epithelial cells, especially on the epithelial-mesenchymal transition (EMT). Human intrahepatic biliary epithelial cells were loaded to hydrostatic pressure using a commercial device. We found that loading the cells to 50 mmHg hydrostatic pressure induced obvious morphological changes and significantly upregulated vimentin, ZEB1, and pSmad2/3, fibronectin, and collagen 1α. All changes induced by hydrostatic pressure loading were effectively mitigated by either ROCK inhibitor (Y-27632) or ALK5 inhibitor (SB-431542). Our in vitro experimental data suggests that hydrostatic pressure loading induces EMT of cholangiocytes through RhoA/ROCK and TGF-β/Smad pathways. Elevated hydrostatic pressure in biliary duct system under pathological states may promote the biliary epithelial cells shifting to profibrotic and mesenchymal characteristics.

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Angel, Ross J., Maciej Bujak, Jing Zhao, G. Diego Gatta e Steven D. Jacobsen. "Effective hydrostatic limits of pressure media for high-pressure crystallographic studies". Journal of Applied Crystallography 40, n. 1 (12 gennaio 2007): 26–32. http://dx.doi.org/10.1107/s0021889806045523.

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The behavior of a number of commonly used pressure media, including nitrogen, argon, 2-propanol, a 4:1 methanol–ethanol mixture, glycerol and various grades of silicone oil, has been examined by measuring the X-ray diffraction maxima from quartz single crystals loaded in a diamond-anvil cell with each of these pressure media in turn. In all cases, the onset of non-hydrostatic stresses within the medium is detectable as the broadening of the rocking curves of X-ray diffraction peaks from the single crystals. The onset of broadening of the rocking curves of quartz is detected at ∼9.8 GPa in a 4:1 mixture of methanol and ethanol and at ∼4.2 GPa in 2-propanol, essentially at the same pressures as the previously reported hydrostatic limits determined by other techniques. Gigahertz ultrasonic interferometry was also used to detect the onset of the glass transition in 4:1 methanol–ethanol and 16:3:1 methanol–ethanol–water, which were observed to support shear waves above ∼9.2 and ∼10.5 GPa, respectively, at 0.8–1.2 GHz. By contrast, peak broadening is first detected at ∼3 GPa in nitrogen, ∼1.9 GPa in argon, ∼1.4 GPa in glycerol and ∼0.9 GPa in various grades of silicone oil. These pressures, which are significantly lower than hydrostatic limits quoted in the literature, should be considered as the practical maximum limits to the hydrostatic behavior of these pressure media at room temperature.

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Miki, K., M. R. Klocke, S. K. Hong e J. A. Krasney. "Interstitial and intravascular pressures in conscious dogs during head-out water immersion". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 257, n. 2 (1 agosto 1989): R358—R364. http://dx.doi.org/10.1152/ajpregu.1989.257.2.r358.

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Water immersion (WI) causes an increase in plasma volume in humans and dogs. To determine the mechanism for this fluid movement, the transmission of external water hydrostatic pressure to the interstitial and vascular compartments was studied in six conscious dogs. Systemic arterial, central venous, peripheral arterial (ulnar artery) and venous (cephalic vein), pleural, intra-abdominal, and interstitial fluid hydrostatic (by Guyton's capsule and wick catheter method) pressures and external reference water pressure were measured at three different levels of WI: 1) extremities only, 2) midchest, and 3) midcervical levels at 37 degrees C. There was a significant linear relationship between interstitial fluid hydrostatic pressure (X) and external water pressure (Y): (Y = 0.86X + 1.4, r = 0.93 by Guyton's capsule; Y = 0.85X + 2.4, r = 0.93 by wick catheter. However, vascular pressures did not change when dogs were immersed at the level of the extremities. These pressures increased only during WI at the midchest and midcervical levels. Therefore the pressure gradient that develops between the interstitial and intravascular compartments is probably the major reason for the transcapillary fluid shift during WI.

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Lammi, M. J., R. Inkinen, J. J. Parkkinen, T. Häkkinen, M. Jortikka, L. O. Nelimarkka, H. T. Järveläinen e M. I. Tammi. "Expression of reduced amounts of structurally altered aggrecan in articular cartilage chondrocytes exposed to high hydrostatic pressure". Biochemical Journal 304, n. 3 (15 dicembre 1994): 723–30. http://dx.doi.org/10.1042/bj3040723.

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The effect of hydrostatic pressure on proteoglycan (PG) metabolism of chondrocyte cultures was examined using a specially designed test chamber. Primary cultures of bovine articular chondrocytes at confluence were exposed for 20 h to 5 and 30 MPa continuous hydrostatic pressures and 5 MPa hydrostatic pulses (0.017, 0.25 and 0.5 Hz) in the presence of [35S]sulphate. Northern blot analyses showed that chondrocyte cultures used in this study expressed abundant mRNA transcripts of aggrecan, typical of chondrocytes, but not versican. The cultures also expressed biglycan and decorin. Enzymic digestions with keratanase and chondroitinases AC, ABC and B and subsequent SDS/agarose gel electrophoresis confirmed the synthesis of aggrecans and small dermatan sulphate PGs. The continuous 30 MPa pressure reduced total PG synthesis by 37% as measured by [35S]sulphate incorporation, in contrast to the 5 MPa continuous pressure which had no effect. The high static pressure also reduced total [3H]glucosamine incorporation by 63% and total [14C]leucine incorporation by 57%. The cyclic pressures showed a frequency-dependent stimulation (0.5 Hz, 11%) or inhibition (0.017 Hz, -17%) of [35S]sulphate incorporation. Aggrecans secreted under continuous 30 MPa pressure showed a retarded migration in 0.75% SDS/agarose gel electrophoresis and they also eluted earlier on Sephacryl S-1000 gel filtration, indicative of a larger molecular size. The increased size was consistent with an increase of average glycosaminoglycan chain length as determined by Sephacryl S-300 gel filtration. No change in aggrecan size was observed with the lower (5 MPa) static or cyclic pressures. Continuous 30 MPa hydrostatic pressure slightly reduced the steady-state mRNA level of aggrecan, in parallel with the decline in PG synthesis measured by [35S]sulphate incorporation. The results demonstrated that high hydrostatic pressure could influence the synthesis of PGs, especially of aggrecans, in chondrocytes both at the transcriptional and translational/post-translational levels.

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Kim, JeongHyun, Kevin Montagne, Takashi Ushida e Katsuko S. Furukawa. "10205 Effect of Hydrostatic pressure on chondrogenesis and c-Fos". Proceedings of Conference of Kanto Branch 2014.20 (2014): _10205–1_—_10205–2_. http://dx.doi.org/10.1299/jsmekanto.2014.20._10205-1_.

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Higashi, Eiji, Masahiko Yoshino e Kousuke Kawade. "Machining Test under External hydrostatic Pressure(Advanced machining technology (continued))". Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 2005.2 (2005): 523–28. http://dx.doi.org/10.1299/jsmelem.2005.2.523.

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Pavlou, Dimitrios. "Subsea FRP pipeline performance in external pressure: Failure and external pressure-induced buckling". IOP Conference Series: Materials Science and Engineering 1201, n. 1 (1 novembre 2021): 012040. http://dx.doi.org/10.1088/1757-899x/1201/1/012040.

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Abstract The Subsea pipelines are subjected to high hoop stresses due to the hydrostatic pressure. When the internal pressure of the liquid has a higher value than the external hydrostatic one, there is a balance of the tensile and compressive stresses. However, during the offshore installation, the subsea pipelines are empty and the compression due to the hydrostatic pressure of the sea is predominant. High compressive stresses in FRP pipelines can cause failure or buckling. In the present work, an investigation of the external pressure-induced failure and buckling is carried out. Analytical formulae and results are provided and discussed.

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Khraibi, A. A., J. P. Granger, J. A. Haas, J. C. Burnett e F. G. Knox. "Intrarenal pressures during direct inhibition of sodium transport". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 263, n. 6 (1 dicembre 1992): R1182—R1186. http://dx.doi.org/10.1152/ajpregu.1992.263.6.r1182.

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Renal interstitial hydrostatic pressure (RIHP) has been implicated in the regulation of sodium excretion. Studies using vasodilators and other maneuvers to increase RIHP have found a significant correlation between RIHP and sodium excretion. Since correlative studies do not prove a cause-and-effect relationship, it is not known whether the rise in sodium excretion in these studies is the result of increases in RIHP or if RIHP is elevated as a result of decreases in sodium and water reabsorption and increases in intratubular pressure. Therefore, the purpose of the present study was to determine whether elevation of intratubular hydrostatic pressures in response to direct inhibition of tubule transport with loop diuretics results in increases in RIHP in dogs and rats. Intrarenal hydrostatic pressures, renal hemodynamics, and sodium and water excretion were examined in dogs during intravenous administration of furosemide (3 mg/kg bolus followed by 0.03 mg.kg-1 x min-1) or bumetanide (60 micrograms/kg bolus followed by 1 microgram.kg-1 x min-1). Furosemide administration increased urinary flow rate (V; 0.10 +/- 0.02 to 4.6 +/- 0.97 ml/min), urinary sodium excretion (UNaV; 16 +/- 5 to 549 +/- 123 mu eq/min), and proximal tubule hydrostatic pressure (PT; 21 +/- 1 to 28 +/- 1 mmHg) but had no effect on RIHP (7.2 +/- 0.6 to 7.4 +/- 0.7 mmHg) or peritubular capillary hydrostatic pressure (14 +/- 1 to 14 +/- 1 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

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KARATZAS (Κ.Α.Γ. ΚΑΡΑΤΖΑΣ), K. Α. G. "High Hydrostatic Treatment of Foods". Journal of the Hellenic Veterinary Medical Society 55, n. 4 (6 dicembre 2017): 324. http://dx.doi.org/10.12681/jhvms.15131.

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Heat Treatment (cooking, boiling, roasting, pasteurisation, sterilisation etc.) has always been for centuries the principal method used in Food Preservation. Lately, recent trends in processing are aimed at more healthy, nutritious and convenient food. New food preservation techniques, new concepts (Hurdle Technology) have been developed and are currently being used in the Food Industry. One of the most promising and already applied,tested in the international market, novel techniques is the High Hydrostatic Pressure treatment. Principal usage of High Hydrostatic Pressure treatment (200-600 MPa) is the pasteurization of foods, where the use of heat treatment is not applicable or in cases where maximum retention of the nutritional value of food is needed. In contrast to thermal processing, High Hydrostatic Pressure treatment can inactivate microorganisms and unfavourable enzymes at ambient or low temperatures, without affecting flavour, colour or nutritional constituents within a food system. High Hydrostatic Pressure could also inactivate food parasites, prions viruses and prionsviruses. It is an excellent pasteurisation and in the future it will turn to be even a sterilisation method. High Hydrostatic Pressure treatment affects almost all cellular processes and parts ofthe cell, with more prominent targets the macromolecular synthesis, the proteins and the cellular membrane. The main problem of this method is the occurrence of piezotolerant strains of microorganisms with great deviations regarding their piezotolerance, that could cause problems in the design of the treatment. This phenomenon is mosdy related with the production of stress proteins. The problem could be solved by the use of combined processes of High Hydrostatic Pressure with other methods or with higher pressures achieved by the technological development of the method. Despite the above-mentioned problems, High Hydrostatic Pressure is a method that advances fast and is taking its place in the modern Food Industry, considering that only a decade passed since the first High Hydrostatic Pressure treated products were presented in the market. The Greek Food Industry and Research Sector should take advantage of the developments in HHP, as this method could improve substantially the quality and competitiveness of the Greek agricultural products.

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Khorramshahi, Mahya, e Mohammad Reza Mohammadizadeh. "Y3Ba5Cu8Ox Superconductor Under Hydrostatic Pressure". Journal of Low Temperature Physics 203, n. 3-4 (16 marzo 2021): 309–18. http://dx.doi.org/10.1007/s10909-021-02583-x.

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Sonkin, D. M., Yu G. Svinolupov e S. A. Mityaev. "Digital hydrostatic well pressure sensor". Neftyanoe khozyaystvo - Oil Industry, n. 1 (2018): 78–81. http://dx.doi.org/10.24887/0028-2448-2018-1-78-81.

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49

Symington, A. L., S. Zimmerman, J. Stein, G. Stein e A. M. Zimmerman. "Hydrostatic pressure influences histone mRNA". Journal of Cell Science 98, n. 1 (1 gennaio 1991): 123–29. http://dx.doi.org/10.1242/jcs.98.1.123.

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Exposure of HeLa S3 cells to high hydrostatic pressure (6.89 × 10(3) to 6.89 × 10(4) kPa: 1000 to 10,000 lbfin-2) reduced core and H1 histone mRNA levels as determined by hybridization to specific histone DNA probes. At 4.14 × 10(4) kPa for 10 min core histone and H1 histone mRNA levels were reduced 32–38% and 56%, respectively. At 30 min postdecompression core mRNA levels returned to atmospheric control levels while H1 histone mRNA levels continued to be suppressed. Levels of macromolecular synthesis were monitored under hydrostatic pressure with radioactive precursors of RNA, DNA and protein. Macromolecular synthesis was shown to be suppressed in a dose-dependent manner with increasing magnitude and duration of pressure. To determine the influence of pressure on histone mRNA stability, actinomycin D (10 micrograms ml-1) was used to block RNA synthesis. Relative amounts of H4 and H1 mRNA were determined at atmospheric pressure and following treatment with actinomycin D (10 micrograms ml-1), pressure (4.14 × 10(4) kPa) and a combination of pressure and actinomycin D. This study shows that a synthesis component and a stability component are involved in the pressure-induced reduction of core histone mRNA. At 4.14 × 10(4) kPa for 15 min, there was a 42% reduction in core histone mRNA of which approximately one third was due a suppression of transcription and two thirds to a loss of mRNA stability. The pressure-induced reduction in histone mRNA is attributed to the instability of endogenous histone mRNA and a reduction in transcription/processing of new histone mRNA.

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Glauser, Frederick L. "Derived pulmonary capillary hydrostatic pressure". Critical Care Medicine 19, n. 11 (novembre 1991): 1335–36. http://dx.doi.org/10.1097/00003246-199111000-00003.

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