scholarly journals Correlation of IOP with Corneal Acoustic Impedance in Porcine Eye Model

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Jun Zhang ◽  
Yi Zhang ◽  
Yang Li ◽  
Ruimin Chen ◽  
K. Kirk Shung ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Linear Correlation ◽  
Acoustic Impedance ◽  
Mean Value ◽  
Reflection Model ◽  
Strong Linear Correlation ◽  
The Mean ◽  
Transducer Frequency ◽  
Transmission And Reflection

Purpose. The aim of this study is to correlate the intraocular pressure (IOP) change with the acoustic impedance of the cornea, in order to propose a noncontact and noninvasive method for IOP monitoring.Methods and Materials. A highly focused transducer (frequency 47-MHz; bandwidth 62%) was made to measure the echo from the anterior and posterior surfaces of intact porcine eyes, respectively. A multilayered transmission and reflection model was used to calculate the acoustic impedance. The linear relationship between acoustic impedance and intraocular pressure was analyzed by statistical method.Result.During pressure elevation from 10 mm Hg to 50 mm Hg, the mean acoustic impedance of the posterior cornea increased from 1.5393 to 1.5698 MRayl, which showed a strong linear correlation (R=0.9849;P=0.0022). Meanwhile, the mean value of the anterior cornea increased from 1.5399 to 1.5519 MRayl, and a less significant correlation was observed (R=0.7378;P=0.0025).Conclusion. This study revealed a linear correlation between intraocular pressure and acoustic impedance of the cornea, thus demonstrating a potentially important method to noninvasively measure the intraocular pressure in vivo.

scholarly journals Detection of the Strains Induced in Murine Tibias by Ex Vivo Uniaxial Loading with Different Sensors

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5109
Author(s):  
Emanuele Rizzuto ◽  
Barbara Peruzzi ◽  
Mariagrazia Giudice ◽  
Enrica Urciuoli ◽  
Erika Pittella ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ex Vivo ◽  
Mean Value ◽  
Uniaxial Loading ◽  
Image Correlation ◽  
Strain Gauges ◽  
Experimental Conditions ◽  
The Mean

In this paper, the characterization of the main techniques and transducers employed to measure local and global strains induced by uniaxial loading of murine tibiae is presented. Micro strain gauges and digital image correlation (DIC) were tested to measure local strains, while a moving coil motor-based length transducer was employed to measure relative global shortening. Local strain is the crucial parameter to be measured when dealing with bone cell mechanotransduction, so we characterized these techniques in the experimental conditions known to activate cell mechanosensing in vivo. The experimental tests were performed using tibia samples excised from twenty-two C57BL/6 mice. To evaluate measurement repeatability we computed the standard deviation of ten repetitive compressions to the mean value. This value was lower than 3% for micro strain gauges, and in the range of 7%–10% for DIC and the length transducer. The coefficient of variation, i.e., the standard deviation to the mean value, was about 35% for strain gauges and the length transducer, and about 40% for DIC. These results provided a comprehensive characterization of three methodologies for local and global bone strain measurement, suggesting a possible field of application on the basis of their advantages and limitations.

Effect of manual eyelid manipulation on intraocular pressure measurement by rebound tonometry

2018 ◽  
Vol 102 (11) ◽  
pp. 1515-1519 ◽  
Author(s):  
Sung Uk Baek ◽  
Ahnul Ha ◽  
Young Kook Kim ◽  
Jin Wook Jeoung ◽  
Ki Ho Park
Keyword(s):  
Intraocular Pressure ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Mean Value ◽  
Applanation Tonometry ◽  
Palpebral Fissure ◽  
Altman Plot ◽  
Bland Altman Plot ◽  
Rebound Tonometry ◽  
The Mean

Background/aimsTo investigate the effect of eyelid manipulation on the measurement of intraocular pressure (IOP) using two different tonometries (rebound tonometry (RT) vs Goldmann applanation tonometry (GAT)).Methods103 patients with primary open-angle glaucoma were prospectively enrolled. For all of the patients, IOP measurements were performed in three different ways: (1) RT with lid manipulation (LM), (2) RT without LM and (3) GAT. The order of the three measurements was randomly selected. Additionally, the palpebral fissure height (PFH; elliptical space between upper and lower eyelids) was measured.ResultsThe mean value of IOP measured by GAT was 13.97±2.80 mm Hg, which was not significantly different from that by RT without LM (13.75±2.44 mm Hg; P=0.096), but which was significantly lower than that by RT with LM (15.21±2.91 mm Hg; P<0.001). On a Bland-Altman plot, RT with LM was overestimated relative to GAT (mean: −1.5) and RT without LM (mean: −1.2). Among the high IOPs (>20 mm Hg), interestingly, those measured by RT without LM were significantly lower than those measured by GAT (P<0.001). In the subgroup analysis of PFH, the smaller the PFH, the more exaggerated the IOP difference between GAT (P=0.014) and RT with LM (P<0.001).ConclusionRT-measured IOP was significantly exaggerated when manipulation was applied to the eyelid. This overall trend was more pronounced when PFH was small. GAT-measured IOP, meanwhile, showed a good correlation with IOP measured using RT without LM.

In Vitro and in Vivo Measurement of Total Antiplasmin Activity

1977 ◽  
Vol 37 (02) ◽  
pp. 216-221 ◽  
Author(s):  
Osamu Matsuo ◽  
Hisashi Mihara
Keyword(s):  
Plasma Volume ◽  
Fibrinolytic Activity ◽  
Mean Value ◽  
Rabbit Plasma ◽  
In Vivo Measurement ◽  
The Mean ◽  
Infusion Speed

SummaryTotal antiplasmin was measured in vitro and in vivo. In the former case, rabbit plasma was mixed with various concentrations of Urokinase (UK) and the least concentration for appearance of fibrinolytic activity was estimated. This concentration was multiplied by the plasma volume of the rabbit to give the in vitro total antiplasmin. The mean value for 14 rabbits was 4,068.6 units.In order to estimate the total antiplasmin in vivo, UK solution was infused into rabbits. The infusion speed was multiplied by the time of the first appearance of fibrinolytic activity to give the total antiplasmin, although when the infusion speed was low, fibrinolytic activity did not appear during infusion. The mean in vivo total antiplasmin calculated for 6 cases where the infusion speed was high and fibrinolytic activity was observed, was 28,699.8 units, i.e. about 7 (range, 3-11) times the in vitro value.

Respiratory quotients of human kidney in vivo

1963 ◽  
Vol 18 (4) ◽  
pp. 815-817 ◽  
Author(s):  
Earl S. Barker ◽  
Archer P. Crosley ◽  
John K. Clark
Keyword(s):  
Human Subjects ◽  
Human Kidney ◽  
Mean Value ◽  
Whole Body ◽  
Mean Values ◽  
Anesthetized Dogs ◽  
The Mean ◽  
Urine Formation ◽  
Analytical Errors

Renal respiratory quotient (RQ) has been calculated from data collected in unanesthetized human subjects. In contrast to RQ recently reported on anesthetized dogs, these data do not indicate a mean value greater than 1. Under control conditions in 24 subjects, renal RQ calculated without special corrections averaged 0.88. Correcting for differences in blood flow between renal artery and vein due to urine formation the mean was 0.73, with 95% confidence limits 0.49–0.97. With alkaline urines an additional correction for urinary excretion of CO2 is advised. Excluding procedures known to alkalinize the urine, RQ values were similar in 46 observations after a variety of experimental procedures. Since both numerator and denominator of the ratio involve small differences between large values, small analytical errors can produce large changes indistinguishable from physiologic variation. Therefore mean values rather than individual observations are stressed. While such values in our data appear similar to RQ for other organs and the whole body, they do not preclude considerable anaerobic metabolism. Submitted on August 9, 1962

Assembly of three major subclasses of mouse immunoglobulin G: a theoretical model for covalent assembly in vivo

1976 ◽  
Vol 54 (8) ◽  
pp. 688-698 ◽  
Author(s):  
J. R. Percy ◽  
M. E. Percy ◽  
R. Baumal
Keyword(s):  
Cell Lines ◽  
Immunoglobulin G ◽  
Mean Value ◽  
Individual Values ◽  
In Vitro Assembly ◽  
The Mean ◽  
The Individual ◽  
Mouse Myeloma

A mathematical model, based on second-order reaction kinetics, has been used to describe the covalent assembly of immunoglobulin G (IgG) in vitro from its heavy (H) and light (L) chains (Percy, M. E., Baumal, R., Dorrington, K. J. &Percy, J. (1976) Can. J. Biochem. 54, 675–687). In the present paper, the same model has now been applied to the steady-state assembly of IgG in vivo. This mathematical approach permits a quantitative comparison of the pathways of covalent assembly used by given immunoglobulins in vivo and in vitro. The assumptions in the model are: the species L, H, HL, HH, HHL and LHHL belong to a common pool; incompleted IgG intermediates may freely assemble to form HL, HH, HHL and LHHL; the reaction rate for covalent linkage between any two reacting species is proportional to the products of the number densities of the reactants and to a parameter P which takes the value PHH if the reaction joins two H chains, and PHL if it joins an H and L chain. In vivo values of PHH/PHL were determined for the 18 mouse myeloma tumours and cell lines studied by Baumal et al. (Baumal, R., Potter, M. &Scharff, M. (1971) J. Exp. Med. 134, 1316–1334). From these analyses, we have arrived at the following conclusions: (1) the three major IgG subclasses have distinctive values of PHH/PHL (mean value 53 for IgG1, 12 for IgG2a and 2.8 for IgG2b); (2) for IgGs of the same subclass, the values of PHH/PHL are similar; (3) the mean in vivo values of PHH/PHL are very close to those determined from in vitro assembly experiments. Finally, the individual values of PHH/PHL have been used to simulate pulse-chase experiments in the various tumours and cell lines. Considering the sources and magnitude of experimental error, the theoretical pathways of assembly agree with those determined qualitatively from the pulse-chase experiments.

Effects of Joint Discontinuity on the Vibration Power Flow Propagation in a Submerged Cylindrical Shell

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Yun Wang ◽  
Gangtie Zheng
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Shell Theory ◽  
Pressure Field ◽  
Mean Value ◽  
Propagation Characteristics ◽  
Vibration Power Flow ◽  
The Mean ◽  
Flow Propagation ◽  
Transmission And Reflection

The propagation characteristics of the vibration power flow in a submerged cylindrical shell with joint discontinuity are investigated by the wave propagation approach. The motion of the cylindrical shell and the pressure field in fluid are described by the Flügge shell theory and the Helmholtz equation, respectively. And the dynamic equations of the system are obtained by the coupling between the shell and the fluid. Then, an analysis of the vibration power flow transmission and reflection at the joint discontinuity is presented and the power flow transmission ratio Tr through the joint discontinuity is studied. Results show that the joint discontinuity can reduce the mean value of the Tr and thus, reduce the energy level of the transmitted vibration, as it has the effect of partially reflecting some of the incident wave with relations to its physical and geometric parameters. The influences of the fluid and the material damping of the joint discontinuity are also studied.

scholarly journals The limit of tolerable micromotion for implant osseointegration: a systematic review

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nupur Kohli ◽  
Jennifer C. Stoddart ◽  
Richard J. van Arkel
Keyword(s):  
Systematic Review ◽  
Research Effort ◽  
Mean Value ◽  
Development Research ◽  
Implant Loosening ◽  
Bone Implant ◽  
The Mean ◽  
Porous Biomaterials ◽  
Fibrous Capsule Formation

AbstractMuch research effort is being invested into the development of porous biomaterials that enhance implant osseointegration. Large micromotions at the bone-implant interface impair this osseointegration process, resulting in fibrous capsule formation and implant loosening. This systematic review compiled all the in vivo evidence available to establish if there is a universal limit of tolerable micromotion for implant osseointegration. The protocol was registered with the International Prospective Register for Systematic Reviews (ID: CRD42020196686). Pubmed, Scopus and Web of Knowledge databases were searched for studies containing terms relating to micromotion and osseointegration. The mean value of micromotion for implants that osseointegrated was 32% of the mean value for those that did not (112 ± 176 µm versus 349 ± 231 µm, p < 0.001). However, there was a large overlap in the data ranges with no universal limit apparent. Rather, many factors were found to combine to affect the overall outcome including loading time, the type of implant and the material being used. The tables provided in this review summarise these factors and will aid investigators in identifying the most relevant micromotion values for their biomaterial and implant development research.

Blood Gases of the Tench (Tinca tinca) in Well Aerated and Oxygen-Deficient Waters

1974 ◽  
Vol 60 (1) ◽  
pp. 71-83 ◽  
Author(s):  
F. B. EDDY
Keyword(s):  
Venous Blood ◽  
Oxygen Affinity ◽  
Blood Gases ◽  
Mean Value ◽  
Hypoxic Conditions ◽  
Arterial Blood ◽  
The Mean ◽  
Tench Tinca Tinca

1. The respiration of tench at 13°C was investigated, particular attention being given to the role of the blood in uptake and transport of oxygen. 2. In well aerated water the mean value for arterial blood was 36 mmHg, for PCOCO2 3.3 mmHg and for pH 8.16; the respective venous values were 7 mmHg, 5 mmHg and 8.08. Arterial blood averaged about 75% and venous blood about 40° oxygen saturation. The mean value for oxygen uptake was 0.5 ml/min/kg and for ventilation volume 132/ml/mm/kg. 3. The oxygen tension and the percentage saturation of the blood determined in vivo are discussed in terms of the oxygen dissociation curve determined in vitro. 4. When the environmental POO2 was decreased, tench responded by increasing breathing rate and ventilation volume. Arterial POO2 and PCOCO2 decreased but arterial pH tended to remain steady. There was also a significant increase in blood lactate. 5. That tenth can withstand severe hypoxic conditions is attributed to blood of high oxygen affinity and the ability to maintain a favourable acid-base status in the blood for oxygen transport. 6. Respiration in tench is compared with that in other fish species.

Optimum Tryptic Activation of Inactive Renin in Human Plasma is Independent of Endogenous Anti-Tryptic Activity

1981 ◽  
Vol 61 (s7) ◽  
pp. 303s-305s ◽  
Author(s):  
Alessandro Rappelli ◽  
Paolo Dessi'-Fulgheri ◽  
Paolo Madeddu ◽  
Franca Meloni ◽  
Caterina Fiori ◽  
...  
Keyword(s):  
Human Plasma ◽  
Maximum Yield ◽  
Normal Subjects ◽  
Mean Value ◽  
Entire Group ◽  
Maximum Activation ◽  
Inactive Renin ◽  
Tryptic Activity ◽  
The Mean

1. Plasma samples from 31 normal subjects were treated (at 4°C, pH 7.0, for 2 min) with different concentrations of trypsin (500, 1000, 2000, 3000 and 4000 μg/ml) in order to assess which concentration yielded the maximum activation of inactive renin. 2. Endogenous antitryptic activity was also measured in all samples; the mean value ± sd (in μg of trypsin inhibited by 1 ml of plasma) was 953 ± 550 μg/ml (range 34–1800 μg/ml). 3. In the entire group of subjects the values of trypsin-activated renin measured with trypsin at 2000 μg/ml were significantly higher than those obtained with lower or higher trypsin concentrations. 4. With subjects divided into subgroups according to their endogenous anti-tryptic activity, the maximum yield of activation was reached with trypsin at 2000 μg/ml. 5. No significant correlations were found between single values of active, inactive or trypsin-activated renin and the corresponding levels of endogenous anti-tryptic activity. However, a weak but significant correlation (r = 0.39, P &lt; 0.05) was found between single values of anti-tryptic activity and the corresponding percentage of activation of inactive renin. 6. Thus the maximum activation of inactive renin at 4°C for 2 min is obtained with trypsin at 2000 μg/ml independently of the corresponding endogenous anti-tryptic activity. It is not excluded that the content of protease inhibitors in human plasma might affect the proportion in vivo of circulating active and inactive renin.

Quantification of Eye Irritation Based upon In Vitro Changes of Corneal Thickness

1990 ◽  
Vol 17 (3) ◽  
pp. 255-262
Author(s):  
Guido A. Jacobs ◽  
Mark A. Martens
Keyword(s):  
Linear Correlation ◽  
Objective Assessment ◽  
Corneal Thickness ◽  
In Vitro Tests ◽  
In Vitro Test ◽  
Eye Irritation ◽  
The Mean ◽  
Observation Times

Measurement of corneal swelling is an objective assessment of irritation in in vivo tests. The same measurement may be made in in vitro tests using the isolated eye test (IET), which has been recommended by the European Community as an alternative for in vivo eye irritation tests. In order to compare the corneal swelling in vivo and in vitro, tests were performed with 34 substances. The in vitro test results were assessed for their ability to predict eye-irritant potential. The corneal swelling data in vivo after 4, 24, 48 and 72 hours were compared with the in vitro data obtained after 2 and 4 hours. Slight linear correlation was found between the corneal swelling in vivo after 4 hours and the corneal swelling in vitro after 4 hours (r=0.77). The substances tested can be divided into two groups, according to their ability to create opacity in either the epithelial layer or in the stroma. When the substances causing epithelial opacity were omitted from the comparison, a much better linear correlation was obtained between the mean corneal swelling 121 vitro over 2 and 4 hours and the mean corneal swelling calculated in vivo for all animals and over three observation times (24, 48 and 72 hours; r=0.91), the latter being the observation times prescribed by EC legislation (1). A comparison of the mean corneal opacity scores observed in vivo and the mean percentage corneal swelling in vitro gave a satisfactory linear correlation (r=0.89). From this study it can be deduced that a mean corneal swelling of 55%, obtained in isolated eyes over 2 and 4 hours, corresponds with the limit for classification as irritant, to the eye. When this criterion was applied to all substances causing no epithelial opacity (n=28), only one false positive and no false negatives were found.

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