scholarly journals A simple method to calculate synthetic long-period seismograms incorporating first-order asymptotics.

1988 ◽  
Vol 36 (5) ◽  
pp. 229-236 ◽  
Author(s):  
Eiji MOCHIZUKI
Keyword(s):  
Simple Method ◽  
First Order ◽  
Long Period

scholarly journals A rapid simple method for the assay of renin in rabbit plasma

1968 ◽  
Vol 108 (4) ◽  
pp. 679-685 ◽  
Author(s):  
J W Ryan ◽  
J. K. McKenzie ◽  
M. R. Lee
Keyword(s):  
Rabbit Plasma ◽  
Selective Inhibitors ◽  
Angiotensin I ◽  
Simple Method ◽  
Renin Substrate ◽  
First Order ◽  
Complete Inactivation ◽  
Plasma Enzymes ◽  
First Order Kinetics ◽  
Percentage Release

1. EDTA (10mm), 2,3-dimercaptopropan-1-ol (10mm) and chlorhexidine gluconate (0·005%, w/v) cause complete inactivation of plasma enzymes that degrade angiotensin I, but have no effect on the reaction of renin with its substrate. The reagents were termed the selective inhibitors. 2. Thus it is possible to measure renin in plasma by its ability to catalyse the release of angiotensin I. 3. Sterile plasma, treated with the selective inhibitors, is incubated with renin substrate (500–1000ng. of angiotensin content/ml.) at pH6 at 42° for 6hr. 4. Under these conditions the reaction obeys first-order kinetics. Renin activity is calculated in terms of the percentage release of the angiotensin content/hr. 5. As described, the assay is sufficiently sensitive to measure renin in the plasma of all normal rabbits. By extending the length of the incubation, much lower activities can be measured.

scholarly journals First-order loss-less differentiators using long period gratings made in Er-doped fibers

2009 ◽  
Vol 17 (2) ◽  
pp. 461 ◽  
Author(s):  
David Krcmarík ◽  
Radan Slavík ◽  
Yongwoo Park ◽  
Mykola Kulishov ◽  
José Azaña
Keyword(s):  
First Order ◽  
Long Period ◽  
Long Period Gratings ◽  
Doped Fibers ◽  
Er Doped ◽  
Made In

A quick and simple method for determining the titration curve and estimating the lime requirement of soil

Soil Research ◽  
1990 ◽  
Vol 28 (5) ◽  
pp. 685 ◽  
Author(s):  
NJ Barrow ◽  
VC Cox
Keyword(s):  
High Temperature ◽  
Titration Curve ◽  
Simple Method ◽  
Soil Particles ◽  
Long Period ◽  
Slow Reaction ◽  
Rate Of Reaction

We investigated the effects of time and temperature of incubation on the pH of soil to which acid or alkali had been added. Most of the change in pH occurred quickly, but a slow reaction continued for a long period. The rate of this slow reaction was increased by increasing the temperature. The magnitude of the effect suggested that the continuing reaction was due to diffusion of protons into, or out of, the soil particles. Because of the increased rate of reaction at high temperature, it is possible to produce in a few days at 60�C effects similar to several months' incubation at 25�C. This provides a simple means of determining the titration curve and of estimating the lime requirement.

Free‐boundary conditions of arbitrary polygonal topography in a two‐dimensional explicit elastic finite‐difference scheme

Geophysics ◽  
1988 ◽  
Vol 53 (8) ◽  
pp. 1045-1055 ◽  
Author(s):  
Rong‐Song Jih ◽  
Keith L. McLaughlin ◽  
Zoltan A. Der
Keyword(s):  
Free Surface ◽  
Coordinate System ◽  
Practical Interest ◽  
Special Treatment ◽  
Simple Method ◽  
Present Scheme ◽  
Line Segments ◽  
First Order ◽  
Approximate Boundary Condition ◽  
Transition Points

We present a simple method for simulating 2-D elastic waves in a model with free‐surface topography of polygonal shape, i.e., a continuous but irregular surface composed of line segments. Our method requires special treatment for each of the six specific cases involving line segments of various slopes as well as transition points between the sloping segments. For brevity, only nonnegatively sloping segments are specifically included. On an inclined free surface, vanishing stress conditions are implemented using a rotated coordinate system parallel to the inclined boundary. At transition points on the topography between line segments, we use a first‐order approximate boundary condition in a locally rotated coordinate system aligned with the bisector of the corner. As in the classical one‐sided explicit approximation scheme widely used for the flat free‐surface case, these extrapolation formulas are accurate to first order in spatial increment. Numerical tests indicate that the present scheme is stable over a range of Poisson’s ratios of practical interest (v > 0.3) for fairly complicated geometric shapes consisting of ridges and valleys with both steep and gentle slopes. Stability for complicated shapes enables us to study realistic problems for which the topography plays a significant role in shaping the wave field and for which analytical solutions are not generally available.

scholarly journals A Simple Method to Measure Renal Function in Swine by the Plasma Clearance of Iohexol

2017 ◽  
Author(s):  
Sergio Luis-Lima ◽  
Consolación Garcia-Contreras ◽  
Marta Vazquez-Gomez ◽  
Susana Astiz ◽  
Fabiola Carrara ◽  
...  
Keyword(s):  
Plasma Clearance ◽  
Quadratic Equation ◽  
Concordance Correlation ◽  
Limits Of Agreement ◽  
Simple Method ◽  
First Order ◽  
Order Polynomial ◽  
Experimental Trials ◽  
Conscious Animals ◽  
Testing Group

There is no simple method to measure glomerular filtration rate (GFR) in swine, an established model to study renal disease. We developed a protocol to measure GFR in conscious swine with the plasma clearance of iohexol. We used two groups: testing and validation, of 8 animals each. Ten milliliters of iohexol (6.47 g) were injected by the marginal auricular vein and blood samples (3 ml) were collected from the orbital sinus at different points after injection. GFR was determined considering two models: two-compartments (CL2: all samples) and one-compartment (CL1: the last six samples). In the testing group, CL1 overestimated CL2 by ~30%: CL2=245±93 and CL1=308±123 ml/mn. This error was corrected by a first order polynomial quadratic equation to CL1, which was considered the simplified method: SM=-47.909+(1.176xCL1)–(0.00063968xCL12). SM showed narrow limits of agreement with CL2, and a concordance correlation of 0.97 and a total deviation index of 14.73%. Similar results were obtained for the validation group. This protocol is reliable, reproducible, can be performed in conscious animals, uses a single dose of the marker, and requires a reduced number of samples avoiding urine collection. Finally, it portends a significant improvement in animal-welfare conditions and handling necessities in experimental trials.

scholarly journals Simultaneous Determination of N-Butylscopolamine and Oxazepam in Pharmaceutical Formulations by First-Order Digital Derivative Spectrophotometry

2005 ◽  
Vol 88 (4) ◽  
pp. 1173-1178 ◽  
Author(s):  
Maria Inés Toral ◽  
Marcelo A Muñoz ◽  
Sandra L Orellana
Keyword(s):  
Standard Deviation ◽  
Simultaneous Determination ◽  
Relative Standard Deviation ◽  
Pharmaceutical Formulations ◽  
Derivative Spectrophotometry ◽  
Simple Method ◽  
Zero Crossing ◽  
First Order ◽  
Relative Standard

Abstract A simple method has been developed for the simultaneous determination of N-butylscopolamine bromide and oxazepam in pharmaceutical formulations using first-order digital derivative spectrophotometry. Acetonitrile was selected as the solvent in which both compounds showed well-defined bands. Both analytes showed good stability in this solvent when solutions of the analytes were exposed to light and temperatures between 20° and 80°C. The simultaneous determination of both drugs was performed by the zero-crossing method at 226.0 and 257.0 nm for N-butylscopolamine and oxazepam, respectively. The linear range of determination was found to be 2.5 × 10−7 to 8.0 × 10−5 mol/L for N-butylscopolamine and 7.1 × 10−8 to 8.0 × 10−5 mol/L for oxazepam. A very good level of repeatability (relative standard deviation) of 0.2% was observed for N-butylscopolamine and oxazepam. The ingredients commonly found in pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in pharmaceutical formulations (capsules).

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