Статті в журналах: "Volume apparent"

1

Repetto, Horacio A., and Roberto Penna. "Apparent Bicarbonate Space in Children." Scientific World JOURNAL 6 (2006): 148–53. http://dx.doi.org/10.1100/tsw.2006.32.

Повний текст джерела

Анотація:

The amount needed to change the concentration of a solute requires the knowledge of its volume of distribution in the solution. Electrolytes that do not participate in active metabolic reactions have a fixed volume of distribution that corresponds to the volume of water in which they solubilize. Bicarbonate infusion is used to correct hyperchloremic metabolic acidosis. Its volume of distribution (bicarbonate space) changes with its participation in the blood buffer systems. In other words, it is not a fixed physical volume, like that of other solutes. In this paper, we shall review experimental studies that supported evidence for this knowledge and analyze the basic hypothesis to explain the phenomena. Since we have not found clinical studies in children, we shall report our experience in a group of patients with metabolic acidosis treated with bicarbonate infusion in whom apparent bicarbonate space was measured and compared with data in adults from the literature. Guidelines for amount of bicarbonate needed to increase its concentration according to baseline bicarbonate concentration will be suggested.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Kumar, D. "Apparent molar volume of some ω-amino acids in aqueous electrolyte systems". Canadian Journal of Chemistry 77, № 7 (1 липня 1999): 1288–94. http://dx.doi.org/10.1139/v99-117.

Повний текст джерела

Анотація:

Apparent molar volumes (Vϕ) of some ω-amino acids have been determined in aqueous guanidine hydrochloride (6 m GuHCl) and sodium sulphate (2 m Na2SO4) solutions at 288.15 and 298.15 K using a vibrating tube digital densimeter. The transfer volumes of amino acids from water to aqueous electrolyte systems have been reported. The transfer properties are interpreted in terms of strong interactions, based on a cosphere overlap model of guanidine hydrochloride/sodium sulphate molecules with the charged centers of the zwitterions (amino acid molecules), as compared to ion - nonpolar group interactions.Key words: amino acids, denaturation, guanidine hydrochloride, sodium sulphate, apparent molar volume, zwitterions, limiting apparent molar volume.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Quick, Christopher M., David S. Berger, and Abraham Noordergraaf. "Apparent arterial compliance." American Journal of Physiology-Heart and Circulatory Physiology 274, no. 4 (April 1, 1998): H1393—H1403. http://dx.doi.org/10.1152/ajpheart.1998.274.4.h1393.

Повний текст джерела

Анотація:

Recently, there has been renewed interest in estimating total arterial compliance. Because it cannot be measured directly, a lumped model is usually applied to derive compliance from aortic pressure and flow. The archetypical model, the classical two-element windkessel, assumes 1) system linearity and 2) infinite pulse wave velocity. To generalize this model, investigators have added more elements and have incorporated nonlinearities. A different approach is taken here. It is assumed that the arterial system 1) is linear and 2) has finite pulse wave velocity. In doing so, the windkessel is generalized by describing compliance as a complex function of frequency that relates input pressure to volume stored. By applying transmission theory, this relationship is shown to be a function of heart rate, peripheral resistance, and pulse wave reflection. Because this pressure-volume relationship is generally not equal to total arterial compliance, it is termed “apparent compliance.” This new concept forms the natural counterpart to the established concept of apparent pulse wave velocity.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Bons, P. "APPARENT EXTENSIONAL STRUCTURES DUE TO VOLUME LOSS." Proceedings of the Estonian Academy of Sciences. Geology 48, no. 1 (1999): 3. http://dx.doi.org/10.3176/geol.1999.1.01.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Alauddin, J., S. Pande, S. C. Mohanta, and M. Alauddin. "Volumetric Properties of Secondary Butanol and Tertiary Butanol in Water and Aqueous Micellar Systems of Sodium Dodecyl Sulphate." Journal of Scientific Research 12, no. 3 (May 1, 2020): 419–29. http://dx.doi.org/10.3329/jsr.v12i3.44614.

Повний текст джерела

Анотація:

The apparent molal volumes of sec-butanol and t-butanol in water and in aqueous micellar system of sodium dodecyl sulphate have been determined from density measurements at different surfactant concentrations and temperatures. The partial molal volumes of the alcohols in aqueous micellar system at infinite dilution, V20 (mean, mic) were obtained from apparent molal volume data and compared with the corresponding values in aqueous solvent, V20 (mean, aq). The standard partial molal expansibilities, E20 (mean) of the alcohols were evaluated from V20 (mean) data at various temperatures. The transfer apparent molal volumes, ∆φtr0 for the alcohols from water to surfactant-water system are determined from apparent molal volume data. The sign and magnitude of these parameters are used to analyze the location of the solubilizate (alcohols) in the micellar system and the nature of interactions between alcohols and the micellar aggregates.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Greenway, C. V. "Effects of hemorrhage and hepatic nerve stimulation on venous compliance and unstressed volume in cat liver." Canadian Journal of Physiology and Pharmacology 65, no. 11 (November 1, 1987): 2168–74. http://dx.doi.org/10.1139/y87-342.

Повний текст джерела

Анотація:

Intrahepatic blood volume–pressure relationships were studied using plethysmography to measure hepatic blood volume and a hepatic venous long-circuit to control intrahepatic pressure. In cats anesthetized with pentobarbital or with ketamine–chloralose, hemorrhage (to reduce hepatic blood flow to 60% of control) caused marked reductions in hepatic blood volume and intrahepatic pressure but did not significantly change hepatic blood volume–pressure relationships. We were unable to demonstrate an active reflex venous response to hemorrhage in these preparations, although a large passive response occurred. The volume–pressure relationships in innervated livers were different from those in denervated livers: apparent venous compliance was much greater and apparent unstressed volume was zero or negative. Hepatic nerve stimulation in denervated livers caused a marked decrease in hepatic blood volume at low intrahepatic pressures but failed to alter hepatic blood volumes at high intrahepatic pressures (15 mmHg) (1 mmHg = 133.3 Pa). This resulted in large apparent compliances and apparently negative unstressed volumes, as seen in the innervated livers. Thus blood volume–pressure relationships in innervated livers may not give valid measurements of compliance and unstressed volume. A remarkable feature in all these experiments was the linearity of the relationship between hepatic blood volume and intrahepatic pressure. Exudation of fluid begins at higher intrahepatic pressures in innervated compared with denervated livers.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Cui, Wanjing, Hongfang Hou, Jiaojiao Chen, Yafei Guo, Lingzong Meng, and Tianlong Deng. "Apparent molar volumes of sodium arsenate aqueous solution from 283.15 K to 363.15 K at ambient pressure: an experimental and thermodynamic modeling study." Pure and Applied Chemistry 92, no. 10 (October 25, 2020): 1673–82. http://dx.doi.org/10.1515/pac-2019-1102.

Повний текст джерела

Анотація:

AbstractDensities of the sodium arsenate aqueous solution with the molality varied from (0.04165 to 0.37306) mol · kg−1 were determined experimentally at temperature intervals of 5 K from 283.15 K to 363.15 K and ambient pressure using a precise Anton Paar Digital vibrating-tube densimeter. The apparent molar volumes (Vϕ), thermal expansion coefficient (α) and partial molar volume $({\bar V_{\rm{B}}})$ were obtained based on the results of density measurement. The 3D diagram of apparent molar volume against temperature and molality as well as the diagram of thermal expansion coefficient and partial molar volume against molality were plotted, respectively. On the basis of the Pitzer ion-interaction equation of apparent molar volume model, the Pitzer single-salt parameters ($(\beta _{{\rm{M,X}}}^{(0)v},\beta _{{\rm{M,X}}}^{(1)v},{\rm{ }}\beta _{{\rm{M,X}}}^{(2)v}{\rm{ and }}C_{{\rm{M,X}}}^v,MX = N{a_3}As{O_4})$ and their temperature-dependent correlation F(i, p, T) = a1 + a2ln(T/298.15) + a3(T – 298.15) + a4/(620 – T) + a5/(T – 227) (where T is temperature in Kelvin, ai is the correlation coefficient) for Na3AsO4 were obtained on account of the least-squares method. Predictive apparent molar volumes agree well with the experimental values, and those results indicate that the single-salt parameters and their relational coefficients of temperature-dependence for Na3AsO4 obtained are reliable.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Zenk, Karin E., Jeffrey Barnes, and Steven Sarandis. "Apparent volume discrepancy among vials of Indocin I.V." American Journal of Health-System Pharmacy 43, no. 4 (April 1, 1986): 874–78. http://dx.doi.org/10.1093/ajhp/43.4.874.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Mehrotra, K. N., and M. Anis. "Apparent molar volume and viscosity of zirconyl soaps." Colloids and Surfaces A: Physicochemical and Engineering Aspects 122, no. 1-3 (April 1997): 27–32. http://dx.doi.org/10.1016/s0927-7757(96)03822-8.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Casolla, Barbara, Gregory Kuchcinski, Maéva Kyheng, Riyad Hanafi, Jean-Paul Lejeune, Didier Leys, Charlotte Cordonnier, and Hilde Hénon. "Infarct Volume Before Hemicraniectomy in Large Middle Cerebral Artery Infarcts Poorly Predicts Catastrophic Outcome." Stroke 51, no. 8 (August 2020): 2404–10. http://dx.doi.org/10.1161/strokeaha.120.029920.

Повний текст джерела

Анотація:

Background and Purpose: Infarct volumes predict malignant infarcts in patients undergoing decompressive hemicraniectomy (DH) for large middle cerebral artery territory infarcts. The aim of the study was to determine the optimal magnetic resonance imaging infarct volume threshold that predicts a catastrophic outcome at 1 year (modified Rankin Scale score of 5 or death). Methods: We included consecutive patients who underwent DH for large middle cerebral artery infarcts. We analyzed infarct volumes before DH with semi-automated methods on b1000 diffusion-weighted imaging sequences and apparent diffusion coefficient maps. We studied infarct volume thresholds for prediction of catastrophic outcomes, and analyzed sensitivity, specificity, and the area under the curve, a value ≥0.70 indicating an acceptable prediction. Results: Of 173 patients (109 men, 63%; median age 53 years), 42 (24.3%) had catastrophic outcomes. Magnetic resonance imaging b1000 diffusion-weighted imaging and apparent diffusion coefficient infarct volumes were associated to the occurrence of 1-year catastrophic outcome (adjusted odds ratio, 9.17 [95% CI, 2.00–42.04] and odds ratio, 4.18 [95% CI, 1.33–13.19], respectively, per 1 log increase). The optimal volume cutoff of were 211 mL on b1000 diffusion-weighted imaging and 181 mL on apparent diffusion coefficient maps. The 2 methods showed similar sensitivities and specificities and overlapping area under the curve of 0.64 (95% CI, 0.54–0.74). Conclusions: In patients with large middle cerebral artery infarcts, optimal magnetic resonance imaging infarct volume thresholds showed poor accuracy and low specificity to predict 1-year catastrophic outcome, with different b1000 diffusion-weighted imaging and apparent diffusion coefficient thresholds. In the setting of DH, optimal infarct volumes alone should not be used to deny DH, irrespectively of the method used.

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Omar, Qazi Mohammed, Jean-Noël Jaubert, and Javeed A. Awan. "Densities, Apparent Molar Volume, Expansivities, Hepler’s Constant, and Isobaric Thermal Expansion Coefficients of the Binary Mixtures of Piperazine with Water, Methanol, and Acetone at T = 293.15 to 328.15 K." International Journal of Chemical Engineering 2018 (November 14, 2018): 1–10. http://dx.doi.org/10.1155/2018/8689534.

Повний текст джерела

Анотація:

The properties of 3 binary mixtures containing piperazine were investigated in this work. In a first step, the densities for the two binary mixtures (piperazine + methanol) and (piperazine + acetone) were measured in the temperature range of 293.15 to 328.15 K and 293.15 to 323.15 K, respectively, at atmospheric pressure by using a Rudolph research analytical density meter (DDM 2911). The concentration of piperazine in the (piperazine + methanol) mixture was varied from 0.6978 to 14.007 mol/kg, and the concentration of piperazine in the (piperazine + acetone) mixture was varied from 0.3478 to 1.8834 mol/kg. On the other hand, the density data for the (piperazine + water) mixture were taken from the literature in the temperature range of 298.15 to 328.15 K. In a second step, for the 3 investigated systems, the apparent molar volume (Vϕ) and the limiting apparent molar volume (Vϕ0) at infinite dilution were calculated using the Redlich–Mayer equation. The limiting apparent molar volumes (Vϕ0) were used to study the influence of the solute-solvent and solute-solute interactions. The temperature dependency of the apparent molar volumes was used to estimate the apparent molar expansibility, Hepler’s constant ∂2Vϕ0/∂T2P, and isobaric thermal expansion coefficients αP.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Khatun, Roksana, Rajia Sultana, and Ranjit K. Nath. "Volumetric and Ultrasonic Velocity Studies of Urea and Thiourea in Aqueous Solution." Oriental Journal of Chemistry 34, no. 4 (August 28, 2018): 1755–64. http://dx.doi.org/10.13005/ojc/340407.

Повний текст джерела

Анотація:

The observations on the anomalous behavior of urea and the comparison between urea and thiourea in aqueous solutions have been examined by volumetric and ultrasonic sound velocity techniques at different temperature (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K) , atmospheric pressure by using a high accuracy vibrating U-tube digital density and ultrasonic sound velocity analyzer. The apparent molar volume (ϕv) & apparent molar adiabatic compressibility (ϕk) have been calculated from experimental density and ultrasonic sound velocity data respectively and limiting apparent molar volume (ϕv0), limiting apparent molar adiabatic compressibility (ϕk0) have been evaluated from apparent molar volume vs. molality plot as intercept. Apparent molar expansibility (ϕE) was determined from apparent molar volume and hydration number (nH) from adiabatic compressibility. The results show very interesting information about strong solute-solvent & solute-solute interactions, and also elaborate the structure making or breaking behavior in the solution mixtures.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Hou, Hongfang, Wanjing Cui, Jiaojiao Chen, Lingzong Meng, Yafei Guo, and Tianlong Deng. "Volumetric Properties in the NaAsO2 + H2O System at Temperature from 283.15 to 363.15 K and Atmospheric Pressure." Journal of Chemistry 2020 (January 11, 2020): 1–7. http://dx.doi.org/10.1155/2020/9478365.

Повний текст джерела

Анотація:

Densities of sodium arsenite (NaAsO2) aqueous solution with the molality varied from 0.19570 to 1.94236 mol·kg−1 at temperature intervals of 5 K from 283.15 to 363.15 K and 101 ± 5 kPa were measured by a precise Anton Paar Digital vibrating-tube densimeter. Apparent molar volumes (VΦ) and thermal expansion coefficient (α) were obtained on the basis of experimental data. The 3D diagram of apparent molar volume against temperature and molality and the diagram of thermal expansion coefficient against molality were generated. According to the Pitzer ion-interaction equation of the apparent molar volume model, the Pitzer single-salt parameters (βM,X0υ, βM,X1υ, βM,X2υ, and CM,Xυ, MX = NaAsO2) and their temperature-dependent correlation F(i, p, T) = a1 + a2ln (T/298.15) + a3(T − 298.15) + a4/(620 − T) + a5/(T − 227) (where T is temperature in Kelvin and ai are the correlation coefficients) for NaAsO2 were obtained for the first time. The predictive apparent molar volumes agree well with the experimental values, and those results indicated that the single-salt parameters and the temperature-dependent formula are reliable.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Zhou, Yun, Xiao Qing Zuo, and Ting Zhang. "316L Stainless Honeycombs Fabricated by Extruding and Sintering." Advanced Materials Research 146-147 (October 2010): 1921–24. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1921.

Повний текст джерела

Анотація:

Pure 316L powder is used to mix with an additive to prepare a powder mixed paste. 316L honeycombs were fabricated by extruding the powder mixed paste, then dried and sintered. The volume shrinkage and the apparent density of extruded honeycombs after drying and sintering were measured. The effect of sintering temperature on the volume shrinkage, the apparent density and the structure of honeycombs had been studied. The results show that the volume shrinkage and the apparent density of sintered honeycombs increase with sintering temperature from 1120°C to 1200°C , the volume shrinkage varying from 42% to 57%, and the apparent density from 1.9 to 2.9g/cm3 for 80% solids fraction. The volume shrinkage decreases and the apparent density increases with solid fractions increasing. The structure of sintered honeycombs consists of matrix phase α-Fe(Cr,Ni) , complex compounds of silicon, oxygen and inclusion elements. There is oxide film forming on surface of sintered honeycombs.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Baskerville, Tracey A., I. Mhairi Macrae, William M. Holmes, and Christopher McCabe. "The influence of gender on ‘tissue at risk’ in acute stroke: A diffusion-weighted magnetic resonance imaging study in a rat model of focal cerebral ischaemia." Journal of Cerebral Blood Flow & Metabolism 36, no. 2 (September 30, 2015): 381–86. http://dx.doi.org/10.1177/0271678x15606137.

Повний текст джерела

Анотація:

This is the first study to assess the influence of sex on the evolution of ischaemic injury and penumbra. Permanent middle cerebral artery occlusion was induced in male (n = 9) and female (n = 10) Sprague-Dawley rats. Diffusion-weighted imaging was acquired over 4 h and infarct determined from T2 images at 24 h post-permanent middle cerebral artery occlusion. Penumbra was determined retrospectively from serial apparent diffusion coefficient lesions and T2-defined infarct. Apparent diffusion coefficient lesion volume was significantly smaller in females from 0.5 to 4 h post permanent middle cerebral artery occlusion as was infarct volume. Penumbral volume, and its loss over time, was not significantly different despite the sex difference in acute and final lesion volumes.

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Mendes, Aysha. "High volume of opioid prescribing and the apparent consequences." British Journal of Community Nursing 25, no. 1 (January 2, 2020): 48–49. http://dx.doi.org/10.12968/bjcn.2020.25.1.48.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Ghafourian, Taravat, Mohammad Barzegar-Jalali, Nasim Hakimiha, Taravat Ghafourian, and Mark T. D. Cronin. "Quantitative structure-pharmacokinetic relationship modelling: apparent volume of distribution." Journal of Pharmacy and Pharmacology 56, no. 3 (March 2004): 339–50. http://dx.doi.org/10.1211/0022357022890.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Raiche, A. P., and R. G. Gallagher. "Apparent resistivity and diffusion velocity." GEOPHYSICS 50, no. 10 (October 1985): 1628–33. http://dx.doi.org/10.1190/1.1441852.

Повний текст джерела

Анотація:

Formulas are derived to calculate transient electromagnetic (TEM) vertical diffusion velocity as a function of resistivity, time, and transmitter loop size. For large loops on very conductive earths, this velocity depends strongly on loop size. Diffusion velocity is used to calculate apparent resistivity pseudodepth sections (ARPDS) from apparent resistivity time sections. However, ARPDS do not seem to bear an easily discernible relationship to the geoelectric structure. Furthermore, it is shown that the apparent resistivity is not directly related to the volume through which TEM diffusion has occurred.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Aguilar, M., H. Dominguez, and O. Pizio. "Apparent molar volume anomaly in water-dimethyl sulfoxide liquid mixtures. Molecular dynamics computer simulations." Condensed Matter Physics 25, no. 4 (2022): 44201. http://dx.doi.org/10.5488/cmp.25.44201.

Повний текст джерела

Анотація:

We have studied the composition dependence of density of liquid water-DMSO mixtures at different temperatures by using the isobaric-isothermal (NPT) molecular dynamics computer simulations. The non-polarizable semi-flexible, P1 and P2 models for the DMSO molecule combined with the TIP4P-2005 water model are considered. The excess mixing volume and the apparent molar volumes of the species are reported. We have established that the P1-TIP4P-2005 model for the mixture provides a very good description of the location of the minimum of apparent molar volume for DMSO species indicating the anomaly. Most important is that the temperature interval where the hydrophobic effect exists, is correctly captured with this modelling, in contrast to the P2-TIP4P-2005 model.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Savaroglu, Gokhan, and Murat Ozdemir. "Apparent molar volume and apparent molar isentropic compressibility of glycerol in fructose-water at different temperatures." Journal of Molecular Liquids 137, no. 1-3 (January 2008): 51–57. http://dx.doi.org/10.1016/j.molliq.2007.03.007.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Klofutar, Cveto, Jaka Horvat, and Darja Rudan-Tasic. "Apparent Molar Volume and Apparent Molar Expansibility of Rubidium, Cesium, and Ammonium Cyclohexylsulfamate in Aqueous Solution." Monatshefte für Chemie - Chemical Monthly 137, no. 9 (September 2006): 1151–62. http://dx.doi.org/10.1007/s00706-006-0524-y.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Bottomley, GA, and MT Bremers. "Electrolyte Molar Volumes at 273-373-K in Propylene Carbonate, N-Methylformamide, Formamide and Methanol: Their Relation to Solvent Compressibility. Ion Association Constants in Acetonitrile at 298-K." Australian Journal of Chemistry 39, no. 12 (1986): 1959. http://dx.doi.org/10.1071/ch9861959.

Повний текст джерела

Анотація:

Measurements have been made on several electrolytes of their apparent molar volumes at 25°C by dilatometry and typically from 0°C to 125°C by expansimetry in propylene carbonate, N- methylformamide, formamide, and methanol. The electrolyte limiting apparent molar volumes are shown to be linearly related to the temperature dependent isothermal compressibility in these solvents, as in water. Ion-pair equilibrium associated constants have been determined by volumetric means for NH4SCN, KSCN and ten other electrolytes in acetonitrile at 25°C and similarly for MgSO4 in water at 25°C. Less extensive apparent molar volume studies in water 0 to 160°C for high charge species and in liquid sulfur dioxide at 25° are also reported.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Cereda, Maurizio, Yi Xin, Kiarash Emami, Jessie Huang, Jennia Rajaei, Harrilla Profka, Biao Han, et al. "Positive End-expiratory Pressure Increments during Anesthesia in Normal Lung Result in Hysteresis and Greater Numbers of Smaller Aerated Airspaces." Anesthesiology 119, no. 6 (December 1, 2013): 1402–9. http://dx.doi.org/10.1097/aln.0b013e3182a9b0c1.

Повний текст джерела

Анотація:

Abstract Background: Although it is recognized that pulmonary hysteresis can influence the effects of positive end-expiratory pressure (PEEP), the extent to which expansion of previously opened (vs. newly opening) peripheral airspaces contribute to increased lung volume is unknown. Methods: Following a recruitment maneuver, rats were ventilated with constant tidal volumes and imaged during ascending and descending ramps of PEEP. Results: The authors estimated peripheral airspace dimensions by measuring the apparent diffusion coefficient of 3He in 10 rats. In a separate group (n = 5) undergoing a similar protocol, the authors used computerized tomography to quantify lung volume. Hysteresis was confirmed by larger end-inspiratory lung volume (mean ± SD; all PEEP levels included): 8.4 ± 2.8 versus 6.8 ± 2.0 ml (P < 0.001) and dynamic compliance: 0.52 ± 0.12 versus 0.42 ± 0.09 ml/cm H2O (P < 0.001) during descending versus ascending PEEP ramps. Apparent diffusion coefficient increased with PEEP, but it was smaller during the descending versus ascending ramps for corresponding levels of PEEP: 0.168 ± 0.019 versus 0.183 ± 0.019 cm2/s (P < 0.001). Apparent diffusion coefficient was smaller in the posterior versus anterior lung regions, but the effect of PEEP and hysteresis on apparent diffusion coefficient was greater in the posterior regions. Conclusions: The authors’ study results suggest that in healthy lungs, larger lung volumes due to hysteresis are associated with smaller individual airspaces. This may be explained by opening of previously nonaerated peripheral airspaces rather than expansion of those already aerated. Setting PEEP on a descending ramp may minimize distension of individual airspaces.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Guillén-Ludeña, Sebastián, Jorge A. Toapaxi, and Luis G. Castillo. "Flushing Capacity of a Stored Volume of Water: An Experimental Study." Water 14, no. 17 (August 24, 2022): 2607. http://dx.doi.org/10.3390/w14172607.

Повний текст джерела

Анотація:

This paper presents a systematic analysis of the hydraulic flushing capacity of a stored volume of water to remove sediments. This analysis is based on 90 laboratory experiments in which the volume of sediment evacuated was measured for varying initial volumes of water, three bed slopes, and three sediment sizes. The experiments consisted of the rapid emptying of a reservoir by means of suddenly opening a tilting gate downstream. This opening produced an accelerated flow which eroded the mobile bed of the reservoir. The efficacy of flushing, herein defined as the ratio of the volume of sediments evacuated to the volume of water released, increased with the initial slope, and decreased as the initial volume of water increased. In relation to the sediment size, while the results obtained for the coarse and medium sands were very similar to each other, the results obtained for the fine sand were affected by the existence of apparent cohesion in the mobile bed. In comparison to the results obtained for the medium and coarse sands, this apparent cohesion reduced the volume of sediment evacuated by a given volume of water and hence, the efficacy of flushing.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Asal Ahmed Abdulsattar. "Interaction Of Threonine Amino Acid In Aqueous Dimethyl Sulfoxide Solutions At Various Temperatures." Journal of the College of Basic Education 18, no. 74 (January 23, 2023): 155–62. http://dx.doi.org/10.35950/cbej.v18i74.9715.

Повний текст джерела

Анотація:

Apparent molal volume ɸv, apparent molal volumes at infinite dilution ɸov ,the slope Sv and viscosity B and D coefficients for Threonine (Thr) in (2-10)% w/w aqueous Dimethyl Sulfoxide (DMSO) solvents have been calculated respectively from the density and viscosity measurements at different temperatures 298.15,303.15,308.15and 313.15 K. The results are discussed in the light of solute-solvent and solute-solute interaction, and shows that Threonine behave as structure-breaker in aqueous DMSO solvent.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Heck, Anisa, Stefan Nöbel, Bernd Hitzmann, and Jörg Hinrichs. "Volume Fraction Measurement of Soft (Dairy) Microgels by Standard Addition and Static Light Scattering." Food Biophysics 16, no. 2 (February 15, 2021): 237–53. http://dx.doi.org/10.1007/s11483-021-09665-z.

Повний текст джерела

Анотація:

AbstractThe volume fraction of the dispersed phase in concentrated soft (dairy) microgels, such as fresh cheese, is directly related to structure and rheology. Measurement or modeling of volume fraction for soft and mechanically sensitive microgel dispersions is problematic, since responsiveness and rheological changes upon mechanical input for these systems limits application of typical functional relationships, i.e., using apparent viscosity. In this paper, we propose a method to measure volume fraction for soft (dairy) microgel dispersions by standard addition and volume-weighted particle size distributions obtained by static light scattering. Relative particle volumes are converted to soft particle volume fraction, based on spiked standard particle volumes. Volume fractions for two example microgel dispersions, namely, differently produced fresh cheeses, were evaluated before and after post-treatments of tempering and mechanical processing. By selecting the size of standard particles based on size ratios and the levels of the mixing ratios/relative fractions, the method could be applied robustly within a wide range of particle sizes (1 to 500 μm) and multimodal size distributions (up to quadmodal). Tempering increased the volume fraction for both example microgel dispersions (P < 0.05). Subsequent mechanical treatment reduced the volume fraction back to the starting value before tempering (P < 0.05). Furthermore, it was shown that the increase and successive decrease in apparent viscosity with tempering and mechanical post-treatments is not exclusively due to particle aggregation and breakdown, but to volume changes of each particle. For environmentally responsive soft matter, the proposed method is promising for measurement of volume fraction.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Rao, N. P., and Ronald E. Verrall. "Ultrasonic velocity, excess adiabatic compressibility, apparent molar volume, and apparent molar compressibility properties of binary liquid mixtures containing 2-butoxyethanol." Canadian Journal of Chemistry 65, no. 4 (April 1, 1987): 810–16. http://dx.doi.org/10.1139/v87-137.

Повний текст джерела

Анотація:

Ultrasonic velocity and density data of binary systems of water–2-butoxyethanol (BE), 2-butoxyethanol-benzene, and 2-butoxyethanol–decane are reported for temperatures of 25, 40, and 55 °C. Adiabatic compressibility coefficients, apparent molar volumes, and apparent molar compressibilities were calculated from these data. Excess adiabatic compressibility properties were evaluated using volume fraction weighting of the individual component properties to estimate ideal mixture behavior. These results are compared with the data obtained based on the use of mole fraction weighting of the individual component properties for the ideal behavior value. A sharp ultrasonic velocity maximum and compressibility minimum is observed at low BE concentration in mixtures of water–BE at all temperatures. These maxima in ultrasonic velocity and minima in adiabatic compressibility are attributed to the formation of "clathrate-like" structures of water and alcohol. A shift of the velocity maximum towards lower concentrations of BE was observed with increase of temperature. A minimum in the ultrasonic velocity and a maximum in adiabatic compressibility coefficient values are observed in systems of BE–benzene and BE–decane. These results are discussed in terms of the breakdown of associated alcohol structures and the interstitial location of hydrocarbon molecules in alcohol aggregates.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Kharat, Sanjeevan J., and Valmik R. Jondhale. "VOLUMETRIC STUDY OF SACCHARIDE INTERACTIONS (D-ARABINOSE, D-XYLOSE, AND D-GALACTOSE) IN SODIUM SACCHARIN AT 298.15 K." Journal of Advanced Scientific Research 12, no. 03 (August 31, 2021): 152–59. http://dx.doi.org/10.55218/jasr.202112322.

Повний текст джерела

Анотація:

Volumetric investigations are effective for attributing the interactions between saccharides and sodium saccharin in aqueous medium. The densities with the help of bicapillary pycnometer were measured for monosaccharide (D(-)- arabinose, D(+)galactose and D(+)-Xylose) (0.04 to 0.20) m (mol.kg-1) in water and aqueous sodium saccharin solution with molality, m = (0.05, 0.15 and 0.3) at 298.15 K. Experimental data were used to calculate the partial molar volume and apparent molar volume . The corresponding transfer volumes were calculated and showed a positive and increasing trend with concentration for saccharides from water to aqueous medium of sodium saccharin. With the help of McMillan-Mayer theory, the interaction coefficients ( ) and ( ) were calculated. In the presence of sodium saccharin, significant interactions between a hydrophilic group of saccharides and the sodium ion have been reported. Using apparent specific volume values, a sweet taste range was identified for saccharides in the presence of sodium saccharin.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Ghazoyan, Heghine H., and Shiraz A. Markaryan. "VOLUMETRIC PROPERTIES OF SOLUTIONS OF DIMETHYLSULFONE IN ETHANOL-WATER MIXTURE AT TEMPERATURES RANGE OF 298.15-323.15 K." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 7 (August 24, 2017): 27. http://dx.doi.org/10.6060/tcct.2017607.5564.

Повний текст джерела

Анотація:

This paper studies volumetric properties of ternary dimethylsulfone-ethanol-water systems. The biomedical and environmental significance for the fundamental investigations of aqueous solution of dimethylsulfone and influences of third component on volumetric behavior of this system arises from several reasons. In the global sulfur cycle dimethylsulfide is converted to dimethylsulfone leading to an annual atmospheric production of some million tones of dimethylsulfone, much of which would be deposited in rain and snow. In addition, dimethylsulfone has been extensively studied from a medical point of view. It was established that dimethylsulfone is contained in small amounts in human blood and urine. Also of interest is that methionine is transformed into dimethylsulfone in living organisms. In this work densities of solution of dimethylsulfone in ethanol-water mixtures with various compositions have been measured over available concentration range. As it is evident from experimental data, the increase in a temperature leads to the reduction of density. The apparent and partial molar volumes of solutions were determined over the 298.15–323.15K temperature range. As it follows from these data, the apparent molar volumes increase with increasing of temperature. The influence of ethanol on the volumetric behavior has been taken into account by changing the apparent molar volume compared with the apparent molar volume of the binary aqueous solutions of DMSO2. It is found also the effect of the amount of ethanol on the volumetric properties of these solutions. It is interesting that the effect of ethanol on the values of apparent molar volumes does not change monotone with increasing in quantity of ethanol in ethanol-water mixture. In dimethylsulfone+(ethanol-water) solutions the partial molar volume of dimethylsulfone increases when quantity of ethanol in ethanol-water mixture more than 0.5 molar fraction. The observed phenomena are explained by the presence of competition of intermolecular interactions. In the DMSO2-ethanol-water system the strongest interaction between ethanol and water molecules leads to the increase in partial molar volumes for DMSO2.For citation:Ghazoyan H.H., Markaryan S.A. Volumetric properties of solutions of dimethylsulfone in ethanol-water mixture at tempe-ratures range of 298.15-323.15 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 27-33.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Klofutar, Cveto, and Darja Rudan-Tasic. "Apparent Molar Volume and Apparent Molar Expansibility of Lithium, Sodium, Potassium, and Tetramethylammonium Cyclohexylsulfamate in Aqueous Solution." Monatshefte für Chemie - Chemical Monthly 136, no. 10 (September 2, 2005): 1727–36. http://dx.doi.org/10.1007/s00706-005-0360-5.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Carlos, Roberto Sanquetta, Niroh Inoue Mateus, Paula Dalla Corte Ana, Pellico Netto Sylvio, Mognon Francelo, Wojciechowski Jaime, and Lourenco Rodrigues Aurelio. "Modeling the apparent volume of bamboo culms from Brazilian plantation." African Journal of Agricultural Research 10, no. 42 (October 15, 2015): 3977–86. http://dx.doi.org/10.5897/ajar2014.9176.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

32

GHAFOURIAN, T., M. BARZEGARJALALI, S. DASTMALCHI, T. KHAVARIKHORASANI, N. HAKIMIHA, and A. NOKHODCHI. "QSPR models for the prediction of apparent volume of distribution." International Journal of Pharmaceutics 319, no. 1-2 (August 17, 2006): 82–97. http://dx.doi.org/10.1016/j.ijpharm.2006.03.043.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Panda, B. B., G. Dixit, and B. Behera. "Apparent Molar Volume and Viscosity ofN-Ethylpyridinium Iodide in Water." Bulletin of the Chemical Society of Japan 69, no. 2 (February 1996): 301–3. http://dx.doi.org/10.1246/bcsj.69.301.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Bouguerra, Sabah, Hamed Bahri, and Pierre Letellier. "Volumes molaires partiels de composés tensioactifs dans les milieux salins concentrés eau–KCl." Canadian Journal of Chemistry 63, no. 9 (September 1, 1985): 2476–80. http://dx.doi.org/10.1139/v85-410.

Повний текст джерела

Анотація:

Apparent molar volumes of 4 cationic detergents CH3(CH2)nN(CH3)3Br (n = 9, 11, 13, and 15) have been determined in water – potassium chloride mixtures at 298 K over a wide range of concentrations (from 0.5 to 3.5 mol L−1). The small dependence of values of apparent molar volume of micellized detergent on the salt concentration suggests the interactions between amphiphiles themselves and between amphiphiles and their surroundings are not modified by the variation of KCl concentration. Previous results lead to estimates of intrinsic volumes of micellized detergents and consequently actual volumes of the micellar phase in the solution. In addition, apparent molar volumes of dodecyltrimethylammonium bromide and sodium dodecylsulfate have been determined in water – sodium chloride mixtures. The results agree fairly well with the previous conclusions and prove the dissymmetric behaviour of the anions and cations in very highly concentrated aqueous salt solutions.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Hasselbach, Wilhelm. "Pressure Effects on the Interactions of the Sarcoplasmic Reticulum Calcium Transport Enzyme with Calcium and Dinitrophenyl Phosphate." Zeitschrift für Naturforschung C 43, no. 11-12 (December 1, 1988): 929–37. http://dx.doi.org/10.1515/znc-1988-11-1221.

Повний текст джерела

Анотація:

Abstract The effect of hydrostatic pressure on the calcium-dependent hydrolysis of dinitrophenyl phosphate by the sarcoplasmic calcium transport enzyme has been studied. The magnesium dinitrophenyl phosphate complex is the true substrate of the enzyme (K - 7000 M-1) by which it is hydrolyzed at 20 °C with a turnover rate of 4 s-1 . Activation by calcium ions occurs between 0.1 and 1 μM as observed for ATP hydrolysis. The activation volume of the enzyme saturated with both ligands exhibits pronounced pressure-dependence, rising from 25 ml/mol at atmospheric pressure to 80 ml/mol at 100 MPa. The apparent binding volumes for magnesium dinitrophenyl phosphate and calcium are likewise pressure-dependent. The volume changes connected with the binding of magnesium dinitrophenyl phosphate is quite small approaching zero at 100 MPa. The apparent binding volume for calcium greatly increases with pressure from 35 ml/mol at atmospheric pressure to 150 ml/mol at 70 MPa. A nearly constant binding volume of approximately 40 ml/mol results if the effect of pressure on the respective rate constants that contribute to the apparent binding constant, is taken into account. The pressure-dependence of enzyme activity at subsaturating calcium concentrations yields an activation volume of 250 ml/mol related to the rate of calcium binding indicating the occurrence of a transient large volume expansion of the enzyme complex. The volume changes observed for the calcium-dependent interaction of the enzyme with magnesium dinitrophenyl phosphate well agree with that found for magnesium p-nitrophenyl phosphate (W. Hasselbach and L. Stephan, Z. Naturforsch. 42c, 641-652 (1987)) indicating that the found volume changes are intrinsic properties of the transport enzyme, independent of the respective energy donor.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Kipkemboi, Pius K., and Allan J. Easteal. "Densities and viscosities of binary aqueous mixtures of nonelectrolytes: tert-Butyl alcohol and tert-butylamine." Canadian Journal of Chemistry 72, no. 9 (September 1, 1994): 1937–45. http://dx.doi.org/10.1139/v94-247.

Повний текст джерела

Анотація:

The density and shear viscosity of mixtures of tert-butyl alcohol (BuOH) and tert-butylamine (TBA) with water have been determined for various temperatures (288 to 318 K for H2O + BuOH and 288 to 308 K for H2O + TBA) over the whole composition range. Excess molar volumes and apparent molar volumes of the components of each system were calculated from the density data. In both systems the apparent molar volume of the organic component passes through a minimum in the water-rich region. Both systems exhibit large negative excess molar volumes which are essentially independent of temperature at all compositions. The two systems show pronounced maxima in their shear viscosity isotherms.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Palani, R., A. Geetha, and S. V. S. L. Poornima. "Ultrasonic Studies of Some Biomolecules in Aqueous Guanidine Hydrochloride Solutions at 298.15 K." E-Journal of Chemistry 8, no. 3 (2011): 1146–51. http://dx.doi.org/10.1155/2011/856284.

Повний текст джерела

Анотація:

Ultrasonic velocity (U), viscocity (η) and density (ρ) ofL- ascorbic acid, dextrose and sucrose in aqueous guanidine hydrochloride (0.3 m) have been measured at 298.15 K. The derived acoustical parameters namely adiabatic compressibility (β), apparent molal compressibility (ΨK) apparent molal volume (ΨV) limiting apparent molal compressibility (Ψ0K) limiting apparent molal volume (Ψ0V) and their constants (SK, Sv) and viscosityB- coefficient and hydration number (nH) have been computed from the experimental data. The variation of these parameters with respect to the molality of solutes have been explained on the basis of solute-solvent interaction and structure making tendency of the solutes in solvents.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Das, Monalisa, Smrutiprava Das, and A. K. Pattanaik. "Acoustical Behaviour of Sodium Nitroprusside in Aquo-Organic Solvent Media at 308.15 K." Journal of Chemistry 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/942430.

Повний текст джерела

Анотація:

Density and ultrasonic velocity have been measured for sodium nitroprusside in aqueous solutions of CH3OH, ethylene glycol, DMSO, and n-propanol solvents at 308.15 K. A quantitative relationship has been established among the acoustical properties like ultrasonic velocity (U), adiabatic compressibility (β), intermolecular free length (Lf), acoustic impedance (Z), apparent molar compressibility (Kϕ), apparent molar volume (Vϕ), limiting apparent molar compressibility (Kϕ0) limiting apparent molar volume (Vϕ0), and their constants (SK,Sv). From the obtained values, molecular interaction study has been made successfully in the light of these acoustical properties through hydrogen bonding in solute and solvent mixture.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Kabiraz, D. C., T. K. Biswas, M. N. Islam, and M. E. Huque. "Studies on Molecular Interactions of Some Electrolytes in Water by Volumetric and Viscometric Measurments at T= (303.15 to 323.15 K)." Journal of Scientific Research 3, no. 2 (April 28, 2011): 437–44. http://dx.doi.org/10.3329/jsr.v3i2.6288.

Повний текст джерела

Анотація:

The viscosities and densities of potassium chloride, potassium nitrate, magnesium chloride, and magnesium nitrate have been measured at 303.15, 308.15, 313.15, 318.15 and 323.15 K in aqueous solution. The viscosity data were analyzed by using Jones–Dole equation. The values of apparent molar volume, limiting apparent molar volume have been evaluated from the density data. The results were interpreted in the light of ion–ion and ion–solvent interactions and of structural effects of the solutes in solution.Keywords: Density; Apparent molar volume; Viscosity; Jones–Dole equation.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v2i2.6288 J. Sci. Res. 3 (2), 437-444 (2011)

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Lomesh, Shashi Kant, Vikas Nathan, Madhu Bala, and Inesh Kumar. "Interactions of Drug Doxycycline Hyclate with Galactitol in Aqueous Solutions at Different Temperatures by Volumetric and Acoustic Methods." Zeitschrift für Physikalische Chemie 234, no. 11-12 (December 16, 2020): 1853–74. http://dx.doi.org/10.1515/zpch-2019-1386.

Повний текст джерела

Анотація:

AbstractThe experimental values of density, ρ and speed of sound, u of doxycycline hyclate drug (0.002–0.014) mol kg−1 in water and (0.1, 0.2 and 0.4) mol kg−1 of aqueous galactitol solutions at temperatures T = (303.15, 308.15 and 313.15) K and at atmospheric pressure have been reported in the present communication. From the experimental values, various derived parameters such as apparent molar volume (ΦV), apparent molar isentropic compression (ΦK), limiting apparent molar volume ($\phi_{\text{v}}^{\text{o}}$), limiting apparent molar isentropic compression ($\phi_{\text{K}}^{\text{o}}$), limiting apparent molar volume of transfer (Δ$\phi_{\text{V}}^{\text{O}}$), limiting apparent molar isentropic compression of transfer (Δ$\phi_{\text{K}}^{\text{O}}$), limiting apparent molar expansibility ($\phi_{\text{E}}^{\text{o}}$), thermal expansion coefficient (α) and acoustic parameters like isentropic compressibility $({{\kappa}_{\text{S}}})$, intermolecular free length (Lf), and specific acoustic impedance (Z) were calculated. The structure-making behaviour of DH in aqueous galactitol solution was determined on the basis of Hepler’s Equation i.e. on the basis of sign of ${\left({\frac{{{{\text{d}}^{2}}\phi_{\text{V}}^{\text{O}}}}{{{\text{d}}{{\text{T}}^{2}}}}}\right)_{\text{P}}}$. The various derived parameters were utilised to interpret the molecular interactions i.e. solute–solute and solute–solvent existing in the studied system.

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Tinjaca, Dario A., Maria M. Muñoz, Fleming Martinez, Abolghasem Jouyban, and William E. Acree Jr. "Apparent Specific Volumes of Sucrose in Different Aqueous Cosolvent Mixtures at 298.2 K." Pharmaceutical Sciences 24, no. 4 (December 30, 2018): 324–31. http://dx.doi.org/10.15171/ps.2018.46.

Повний текст джерела

Анотація:

Background: Sucrose is the most widely used sweetener in foods and pharmaceuticals. Apparent specific volumes of this excipient in aqueous cosolvent mixtures are not available. Thus, the main objective of this research was to determine this property by measuring the density of several solutions of sucrose in {cosolvent + water} mixtures at 298.2 K. Methods: Sucrose dissolutions were prepared gravimetrically and a thermostatically controlled digital oscillatory method was used to measure the dissolutions density. Results: From density values of sucrose dissolutions and cosolvent mixtures the apparent specific volumes of sucrose were calculated and analyzed based on the sucrose and cosolvent proportions in the mixtures. Conclusion: Useful density values of sucrose solutions at different concentrations in several aqueous cosolvent mixtures are reported at 298.2 K. Finally, a mean apparent specific volume value of 0.632 cm3.g–1 for sucrose in different aqueous-cosolvent mixtures could be adequate for practical purposes in pharmaceutical industries.

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Lopes, Thiago Santos de Almeida, Whelton Brito dos Santos, George Antonio Belmino da Silva, Thyago Nóbrega Silveira, Weruska Brasileiro Ferreira, Patricia Herminio Cunha Feitosa, and Vera Lucia Antunes de Lima. "Effects of the transfer of the São Francisco River waters on the performance of the water treatment plant of Gravatá, Paraíba, Brazil." Water Supply 22, no. 3 (November 22, 2021): 3297–306. http://dx.doi.org/10.2166/ws.2021.404.

Повний текст джерела

Анотація:

Abstract The objective of this study was to evaluate the effects of the transfer of the São Francisco River waters on the quality of the water produced by the water treatment plant of Gravatá (WTP-Gravatá) using multivariate statistics. Monthly means of the variables pH, apparent color and turbidity of raw, decanted and treated waters were used, in addition to the volume accumulated by the Epitácio Pessoa reservoir, during the period from January 2016 to December 2017. The arrival of the transposition waters abruptly changed the apparent color and turbidity of the raw water. In spite of that, the treated water presented low variability of the mentioned parameters, indicating that WTP-Gravatá was able to adapt its treatment. From the factor analysis/principal component analysis (FA/PCA) it was found that changes in reservoir volume alter the apparent color and turbidity of the raw water, requiring interventions in the coagulation/flocculation/decantation stages. The increasing of these parameters in the decanted water overloads the filtration step, raising the apparent color of the treated water. The cluster analysis distinguished the different phases experienced by the Epitácio Pessoa reservoir. The information obtained can help decision-making in WTPs, considering changes in reservoir volumes.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Rennard, S. I., G. Basset, D. Lecossier, K. M. O'Donnell, P. Pinkston, P. G. Martin, and R. G. Crystal. "Estimation of volume of epithelial lining fluid recovered by lavage using urea as marker of dilution." Journal of Applied Physiology 60, no. 2 (February 1, 1986): 532–38. http://dx.doi.org/10.1152/jappl.1986.60.2.532.

Повний текст джерела

Анотація:

Bronchoalveolar lavage is a powerful technique for sampling the epithelial lining fluid (ELF) of the lower respiratory tract but also results in a significant dilution of that fluid. To quantify the apparent volume of ELF obtained by bronchoalveolar lavage, urea was used as an endogenous marker of ELF dilution. Since urea diffuses readily through the body, plasma and in situ ELF urea concentrations are identical; thus ELF volume can be calculated using simple dilution principles. Using this approach, we determined that with a standard lavage procedure, the volume of ELF recovered from a normal human is 1.0 +/- 0.1 ml/100 ml of recovered lavage fluid. Time course experiments in which the saline used for lavage was permitted to remain in the lower respiratory tract for various “dwell times” suggested that diffusion of urea from sources other than recovered ELF can contribute to the total urea recovered resulting in an overestimate of the volume of ELF recovered. Thus, while reasonably accurate, the volume of ELF determined by urea must be considered an overestimate, or “apparent” volume. The ELF albumin concentration based on the apparent ELF volume was 3.7 +/- 0.3 mg/ml, a value that is in good agreement with direct measurements made by other techniques in experimental animals. The density of all inflammatory and immune effector cells on the epithelial surface of the lower respiratory tract, based on the apparent ELF volume, was 21,000 +/- 3,000 cells/microliter, a value that is twofold greater than that in blood.(ABSTRACT TRUNCATED AT 250 WORDS)

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Hadded, M., M. Biquard, P. Letellier, and R. Schaal. "Propriétés volumiques du nitrate d'éthylammonium fondu à 298 K et de ses mélanges avec l'eau." Canadian Journal of Chemistry 63, no. 3 (March 1, 1985): 565–70. http://dx.doi.org/10.1139/v85-092.

Повний текст джерела

Анотація:

Partial molar volumes of water and ethylammonium nitrate EAN are determined accurately in all water–EAN mixtures, between pure water and pure fused salt at 298 K. It has been found that the partial molar volume of water decreases linearly with molar fraction of salt, x, in concentrated solution of EAN (C > 2 mol L−1, x > 0.04). The main thermodynamic relations are established to describe the volumetric behaviour of salt, water, and solution. It has been shown that the intrinsic volume of salt can be identified roughly with the molar volume of the pure fused salt and the value of apparent molar volume of water with the actual volume of water in solution.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Martin, D. S., and J. R. McNeill. "Arginine vasopressin increases apparent whole body capacity in anesthetized cats." American Journal of Physiology-Heart and Circulatory Physiology 258, no. 3 (March 1, 1990): H722—H728. http://dx.doi.org/10.1152/ajpheart.1990.258.3.h722.

Повний текст джерела

Анотація:

The effects of arginine vasopressin (AVP) on capacitance function were assessed in anesthetized cats by draining blood from the superior and inferior venae cavae into an external reservoir and then returning blood to the right atrium at a constant rate. Under these conditions, changes in reservoir volume were assumed to reflect reciprocal changes in whole body capacity. Intravenous infusions of AVP (1, 10, and 100 ng.kg-1.min-1) that elevated plasma AVP concentrations by approximately 30, 400, and 4,000 fmol/ml were associated with concentration-dependent increases in whole body capacity that ranged between 1.6 and 8 ml/kg. In contrast to AVP, intravenous infusions of angiotensin II (5, 10, and 50 ng.kg-1.min-1) had relatively little influence on capacity, whereas norepinephrine administration (300, 1,000, and 3,000 ng.kg-1.min-1) was associated with dose-dependent decreases in capacity of 4.5-10.3 ml/kg. Virtually the entire increase in whole body capacity to AVP can be accounted for by summation of the predicted contributions of an active reflex venodilatatory component and those of a passive component (arterial and cardiopulmonary compartments). Because systemic compliance (delta reservoir volume/delta venous pressure) was not changed by AVP administration, the contribution of a reflex venodilatatory component must be the result of increases in unstressed vascular volume (contained volume at 0 transmural pressure) as opposed to changes in compliance. These results may explain why AVP decreases cardiac output to a greater extent than either angiotensin II or sympathomimetics and, thus, why AVP is a weaker pressor agent in animals with intact autonomic function.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Cheng-Baron, June, Kelvin Chow, Nee Scze Khoo, Ben T. Esch, Jessica M. Scott, Mark J. Haykowsky, John V. Tyberg, and Richard B. Thompson. "Measurements of changes in left ventricular volume, strain, and twist during isovolumic relaxation using MRI." American Journal of Physiology-Heart and Circulatory Physiology 298, no. 6 (June 2010): H1908—H1918. http://dx.doi.org/10.1152/ajpheart.00131.2010.

Повний текст джерела

Анотація:

Left ventricular (LV) active relaxation begins before aortic valve closure and is largely completed during isovolumic relaxation (IVR), before mitral valve opening. During IVR, despite closed mitral and aortic valves, indirect assessments of LV volume have suggested volume increases during this period. The aim of this study is to measure LV volume throughout IVR and to determine the sources of any volume changes. For 10 healthy individuals (26.0 ± 3.8 yr), magnetic resonance imaging was used to measure time courses of LV volume, principal myocardial strains (circumferential, longitudinal, radial), and LV twist. Mitral leaflet motion was observed using echocardiography. During IVR, LV volume measurements showed an apparent increase of 4.6 ± 1.5 ml (5.0 ± 2.0% of the early filling volume change), the LV untwisted by 4.5 ± 1.9° (36.6 ± 18.0% of peak systolic twist), and changes in circumferential, longitudinal, and radial strains were +0.87 ± 0.64%, +0.93 ± 0.57%, and −1.46 ± 1.66% (4.2 ± 3.3%, 5.9 ± 3.3%, and 5.3 ± 7.5% of peak systolic strains), respectively. The apparent changes in volume correlated ( P < 0.01) with changes in circumferential, longitudinal, and radial strains ( r = 0.86, 0.69, and −0.37, respectively) and untwisting ( r = 0.83). The closed mitral valve leaflets were observed to descend into the LV throughout IVR in all subjects in apical four- and three-chamber and parasternal long-axis views by 6.0 ± 3.3, 5.1 ± 2.4, and 2.1 ± 5.0 mm, respectively. In conclusion, LV relaxation during IVR is associated with changes in principal strains and untwisting, which are all correlated with an apparent increase in LV volume. Since closed mitral and aortic valves ensure true isovolumic conditions, the apparent volume change likely reflects expansion of the LV myocardium and the inward bowing of the closed mitral leaflets toward the LV interior.

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Hörberg, Lisa, Daniel Roth, Peter Leander, Sven Månsson, Tobias Fält, Olle Ekberg, and Sophia Zackrisson. "Reproducibility of measurements with a semi-automatic software package for the evaluation of rectal cancer." Acta Radiologica 61, no. 5 (September 11, 2019): 586–94. http://dx.doi.org/10.1177/0284185119873118.

Повний текст джерела

Анотація:

Background Staging of rectal cancer with MRI has major impact on treatment choice and may be of importance in new cancer management strategies such as “wait-and-see” policy. Purpose To assess the reproducibility of a software package recently developed at our department to measure volumes, apparent diffusion coefficient, and the skewness of apparent diffusion coefficient in lymph nodes and tumors in rectal cancer patients before and after chemoradiation treatment. Material and Methods This study included 20 consecutive patients with biopsy-verified rectal cancer, in whom MRI staging had been performed both before and after chemoradiation treatment. The diffusion-weighted images were transferred to the software. The volume, apparent diffusion coefficient, and skewness were determined for 93 lymph nodes and 40 tumors. The volumes were compared with manual measurements of the volume of the same lymph nodes and tumors. Results The agreement in semi-automatic measurements of lymph nodes was very good (ICC = 0.99), and in tumors good (ICC = 0.88). The agreement in manual measurements of lymph nodes was very good (ICC = 0.95) when all lymph nodes were included, but low (ICC = 0.52) if three outliers were excluded. Bland–Altman plots showed clear agreement between manual and semi-automatic measurements in the lymph nodes, but not in measurements of tumors. The values of apparent diffusion coefficient and skewness in tumors differed before and after treatment but did not differ in lymph nodes as a group. Conclusion The software package showed a high degree of reproducibility in measurements on lymph nodes but requires further development to improve the reproducibility of tumor measurements.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Ali, Anwar, Firdoos Ahmad Itoo, and Nizamul Haque Ansari. "Interaction of Some Amino Acids with Sodium Dodecyl Sulphate in Aqueous Solution at Different Temperatures." Zeitschrift für Naturforschung A 66, no. 5 (May 1, 2011): 345–52. http://dx.doi.org/10.1515/zna-2011-0511.

Повний текст джерела

Анотація:

The density ρ, and viscosity η of 0.00, 0.05, 0.10, 0.15, and 0.20 mol kg−1 glycine (Gly), dlalanine (Ala), dl-serine (Ser), and dl-valine (Val) have been measured in 0.002 mol kg−1 aqueous sodium dodecyl sulphate (SDS) at 298.15, 303.15, 308.15, and 313.15 K. These data have been used to calculate the apparent molar volume φv, infinite dilution apparent molar volume φv°, and the standard partial molar volumes of transfer φv° (tr), of the amino acids from water to the aqueous SDS solutions. Falkenhagen coefficient A, Jones-Dole coefficient B, free energies of activation per mole of solvent (aqueous SDS) Δμ1°*, and per mole solute (amino acids) Δμ2°*, also enthalpy ΔH* and entropy ΔS* of activation of viscous flow were evaluated using viscosity data. The molar refraction RD was calculated by using experimental values of the refractive index nD of the systems. The results have been interpreted in terms of ion-ion, ion-polar and hydrophobic-hydrophobic group interactions. The volume of the transfer data suggest that ion-ion intertactions are predominant.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Kumar, A. "Volume properties of aqueous electrolytes. 1. Examination of apparent molal volume data by the Pitzer model." Journal of Chemical & Engineering Data 32, no. 1 (January 1987): 106–9. http://dx.doi.org/10.1021/je00047a029.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

50

King, Maria J., Eid I. Brima, Jack R. Dainty, David A. Barrett, Anthony J. Wright, Gavin Willis, and Paul M. Finglas. "Estimation of the 5-Methyltetrahydrofolate Apparent Volume of Distribution in Humans." Journal of Nutrition 142, no. 2 (January 5, 2012): 389–95. http://dx.doi.org/10.3945/jn.111.143685.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Volume apparent"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями