Peritoneal physicochemical transport mechanisms: Hypotheses, models and controversies

2021 ◽  
pp. 089686082110024
Author(s):  
Matthew B Wolf
Keyword(s):  
Lymph Flow ◽  
Time Varying ◽  
Transport Mechanisms ◽  
Mean Values ◽  
Intraperitoneal Pressure ◽  
Model Predictions ◽  
Time Varying Parameters ◽  
Transport Kinetic ◽  
The Mean ◽  
Parameter Values

This study answers criticisms by Waniewski et al. of the recent paper by Wolf on peritoneal transport kinetic models. Their criticisms centre on the accuracy of the data used for model fits, the hypothesis presented, which involves changes in glucose membrane parameters at high peritoneal glucose concentration and on the necessary techniques required to achieve accurate model parameter estimation. In response, this article shows that (1) the mean values previously captured from graphical depictions of Heimburger et al. are not different than those captured from the recent Waniewski et al. graphs, (2) a much simpler hypothesis is proposed, which centres on intraperitoneal pressure-induced lymph flow during the dialysis dwell and (3) the finding that the new model predictions, with only two constant parameter values, as estimated by the Powell algorithm, give a closer fit than the Waniewski model, which uses many time-varying parameters. The current findings again bring into question of the validity of their vasodilation hypothesis, leading to transient changes in capillary surface area during the dwell.

scholarly journals The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling

2019 ◽  
Vol 262 ◽  
pp. 05014 ◽  
Author(s):  
Cezary Szydłowski ◽  
Jarosław Górski ◽  
Marcin Stienss ◽  
Łukasz Smakosz
Keyword(s):  
Numerical Models ◽  
Asphalt Mixture ◽  
Experimental Result ◽  
Model Parameters ◽  
Test Results ◽  
Mean Values ◽  
Estimated Parameters ◽  
The Mean ◽  
Parameter Values ◽  
Test Outcomes

The paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and fracture-triggering loads, dealing with their dispersion too. The estimated parameters allow to form appropriate numerical models of asphalt mixture specimens. This type of analysis supports the laboratory tests. The paper presents the authors' simplified model considering non-uniform material features. The results reflect the scatter of real laboratory test outcomes. In order to do so an algorithm to calibrate the numerical model parameters was created.

Monitoring Hydraulic Fracture Volume using Borehole to Surface EM and Conductive Proppant

Geophysics ◽  
2020 ◽  
pp. 1-76
Author(s):  
G. Michael Hoversten ◽  
Christoph Schwarzbach
Keyword(s):  
Hydraulic Fracture ◽  
Random Parameter ◽  
Dipole Source ◽  
Electrically Conductive ◽  
Mean Values ◽  
Inverse Solutions ◽  
The Mean ◽  
Stage Properties ◽  
Parameter Values ◽  
True Values

Numerical modeling of a North American hydraulic fracture experiment is done to demonstrate the accuracy with which the volume containing proppant could be estimated when electrically conductive proppant is used. An electromagnetic (EM) acquisition system with surface electric and magnetic field receivers and a grounded electric dipole source is simulated. The source has one electrode on the surface and one down a steel-cased well lateral that is adjacent to the lateral being hydraulically fractured. The simulations are preformed using measured EM noise at the site during hydraulic fracturing. A 3D OcTree finite-difference code is used that allows very fine meshing around the steel casings and fractures that can expand rapidly to the boundaries keeping memory requirements within available resources. The steel well casings are modeled in the forward and inverse solutions. Possible scenarios for source-receiver configurations, proppant conductivity, number of perforations per frac stage, variations in the steel casing properties as well as geometric errors in the locations of receivers and placement of the well laterals are considered. Hydraulic fracture stages are modeled as 3D geobodies with variability in the direction perpendicular to the well. Frac stages are embedded in a layered background model built from logged resistivities. The inversion of the EM data is first done on the pre-frac data for the anisotropic layered background resistivities, steel casing electrical conductivity and magnetic susceptibility. Next, data-differencing between the frac stage and the background or between successive frac stages is used for inversion of frac stage properties. A parametric box model is fit to each stage to estimate volume, length, height and mean stage conductivity. Hundreds of inversions starting from random parameter values are done to calculate parameter mean and standard deviations. The mean values of volume, length, and height are all within 20% of the true values.

Efficient Computation of the Statistics of Reciprocating Engine Dynamics With Dimensional Tolerances

1995 ◽  
Author(s):  
F. Zhang ◽  
A. Sinha ◽  
B. J. Gilmore
Keyword(s):  
Angular Speed ◽  
Time Varying ◽  
Efficient Computation ◽  
Mean Values ◽  
Analytical Technique ◽  
Reciprocating Engine ◽  
Parametric Studies ◽  
The Mean ◽  
Driving Torque ◽  
Crank Mechanism

Abstract Using the alternating frequency/time domain technique and statistical analysis, an efficient analytical technique has been developed to compute the mean values and variances of the crank’s angular speed and driving torque for a stochastically defined internal combustion (I.C) engine. The I. C. engine is represented by a slider-crank mechanism with a discontinuous force on the piston due to the time-varying gas pressure in the cylinder. The tolerances on link lengths and radial clearances and uncertainties in pin location are treated as random variables. The validity of analytical technique is established by comparison with results from Monte Carlo simulation. The results from parametric studies are also presented.

scholarly journals Use of statistical control charts for monitoring the quality of flour

2020 ◽  
Vol 24 (2) ◽  
pp. 50-52
Author(s):  
Dragana Tekić ◽  
Beba Mutavdžić ◽  
Tihomir Novaković
Keyword(s):  
Control Charts ◽  
Statistical Quality Control ◽  
Statistical Control ◽  
Mean Values ◽  
The Mean ◽  
Quality Of Products ◽  
Flour Production ◽  
Parameter Values ◽  
And Storage

The use of statistical quality control in the production and storage processes significantly enhances the overall quality of products. Although various techniques are used for quality monitoring purposes, control charts are considered of paramount importance. In this paper, the ash and moisture contents of the wheat flour type 500 were analyzed using descriptive statistics. Consequently, the control charts for the variations in and the mean values of the parameters considered were created. The control charts obtained for the mean parameter values show that the flour production process was in control relative to both parameters considered, exhibiting only random variations. However, the control charts obtained for the variability in the parameter values considered show special variations, the causes of which require further research in order to maintain the satisfactory quality of flour production.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

Comparative Study of Intranasal, Subcutaneous and Intravenous Administration of Desamino-D-Arginine Vasopressin (DDAVP)

1986 ◽  
Vol 55 (01) ◽  
pp. 108-111 ◽  
Author(s):  
M Köhler ◽  
P Hellstern ◽  
C Miyashita ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Factor Xii ◽  
Additional Advantage ◽  
Mean Values ◽  
Routes Of Administration ◽  
The Mean ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

SummaryThis study was performed to evaluate the influence of different routes of administration on the efficacy of DDAVP treatment. Ten healthy volunteers received DDAVP intranasally (i.n.), subcutaneously (s.c.) and intravenously (i.v.) in a randomized cross-over trial. Factor XII and high molecular weight (HMW)-kininogen levels increased only slightly after DDAVP administration. The mean increase of factor VIII: C was 3.1 (i. v.), 2.3 (s. c.), and 1.3 (i.n.) - fold over baseline. Ristocetin cofactor (von Willebrand factor antigen) increased 3.1 (2.5), 2.0 (2.3) and 1.2 (1.2) - fold over baseline mean values after i.v., s.c. and i.n. DDAVP, respectively. The half-disappearance time of factor VIII and von Willebrand factor (vWF) after DDAVP ranged from five (factor VIII: C) to eight hours (vWF). The mean increase of fibrinolytic activity was more pronounced after i.v. DDAVP. The antidiuretic effect was moderate with no apparent differences between the routes of application. This study provides further evidence that both i.v. and s.c. DDAVP administration result in an appropriate and reliable stimulation of haemostasis. An additional advantage of s. c. administration is its suitability for home treatment.

Comparative Study of effectiveness of mobilization with movement (MWM) and End range mobilization (ERM) techniques in frozen shoulder

2018 ◽  
Vol 4 (4) ◽  
pp. 519-522
Author(s):  
Jeyakumar S ◽  
Jagatheesan Alagesan ◽  
T.S. Muthukumar
Keyword(s):  
Range Of Motion ◽  
Frozen Shoulder ◽  
Type I ◽  
Mean Values ◽  
Functional Activities ◽  
Group A ◽  
The Mean ◽  
Group B

Background: Frozen shoulder is disorder of the connective tissue that limits the normal Range of motion of the shoulder in diabetes, frozen shoulder is thought to be caused by changes to the collagen in the shoulder joint as a result of long term Hypoglycemia. Mobilization is a therapeutic movement of the joint. The goal is to restore normal joint motion and rhythm. The use of mobilization with movement for peripheral joints was developed by mulligan. This technique combines a sustained application of manual technique “gliding” force to the joint with concurrent physiologic motion of joint, either actively or passively. This study aims to find out the effects of mobilization with movement and end range mobilization in frozen shoulder in Type I diabetics. Materials and Methods: 30 subjects both male and female, suffering with shoulder pain and clinically diagnosed with frozen shoulder was recruited for the study and divided into two groups with 15 patients each based on convenient sampling method. Group A patients received mobilization with movement and Group B patients received end range mobilization for three weeks. The outcome measurements were SPADI, Functional hand to back scale, abduction range of motion using goniometer and VAS. Results: The mean values of all parameters showed significant differences in group A as compared to group B in terms of decreased pain, increased abduction range and other outcome measures. Conclusion: Based on the results it has been concluded that treating the type 1 diabetic patient with frozen shoulder, mobilization with movement exercise shows better results than end range mobilization in reducing pain and increase functional activities and mobility in frozen shoulder.

A COMPARISON OF TWO METHODS FOR MEASUREMENT OF ALDOSTERONE SECRETION RATE IN MAN

1966 ◽  
Vol 53 (2) ◽  
pp. 177-188 ◽  
Author(s):  
P. Lund-Johansen ◽  
T. Thorsen ◽  
K. F. Støa
Keyword(s):  
Urinary Excretion ◽  
Normal Subjects ◽  
Secretion Rate ◽  
Aldosterone Secretion ◽  
Simple Method ◽  
Mean Values ◽  
Pathological Conditions ◽  
Significant Difference ◽  
Derivative Method ◽  
The Mean

ABSTRACT A comparison has been made between (A), a relatively simple method for the measurement of aldosterone secretion rate, based on paper chromatography and direct densitometry of the aldosterone spot and (B) a more elaborate isotope derivative method. The mean secretion rate in 9 normal subjects was 112 ± 26 μg per 24 hours (method A) and 135 ± 35 μg per 24 hours (method B). The »secretion rate« in one adrenalectomized subject after the intravenous injection of 250 μg of aldosterone was 230 μg per 24 hours (method A) and 294 μg per 24 hours (method B). There was no significant difference in the mean values, and correlation between the two methods was good (r = 0.80). It is concluded that the densitometric method is suitable for clinical purposes as well as research, being more rapid and less expensive than the isotope derivative method. Method A also measures the urinary excretion of the aldosterone 3-oxo-conjugate, which is of interest in many pathological conditions. The densitometric method is obviously the less sensitive and a prerequisite for its use is an aldosterone secretion of 20—30 μg per 24 hours. Lower values are, however, rare in adults.

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