Time Progression of Hemolysis of Erythrocyte Populations Exposed to Supraphysiological Temperatures

1979 ◽  
Vol 101 (3) ◽  
pp. 213-217 ◽  
Author(s):  
N. A. Moussa ◽  
E. N. Tell ◽  
E. G. Cravalho
Keyword(s):  
Statistical Model ◽  
Distribution Curve ◽  
Time History ◽  
Kinetic Scheme ◽  
First Order ◽  
Arrhenius Dependence ◽  
History Of ◽  
The Mean ◽  
Two Parameters ◽  
Microscope Stage

Populations of erythrocytes in solution were heated “instantaneously” to and maintained at temperatures in the range of 44 to 60°C on a microscope stage specifically designed for this purpose. Simultaneously, the visually observed hemolysis-time history of these cells was measured. The results were successfully correlated on the basis of two models: 1) a kinetic scheme assuming two sequential, first-order reactions by which the cells are first reversibly altered and then irreversibly damaged; and 2) a statistical model for which the number of cells that are damaged at each instant is assumed to be normally distributed. From the experimental data the rate constants for the two reactions in the kinetic model were determined and were found to have an Arrhenius dependence on temperature. By applying the statistical model to the data, we were able to determine the mean and standard deviation of the distribution curve for this model. The logarithms of these latter two parameters vary with temperature in a linear fashion.

Stationary and Transient Response of Cylindrical Shells Under Random Excitation

1988 ◽  
Vol 110 (2) ◽  
pp. 205-209
Author(s):  
A. V. Singh
Keyword(s):  
Transient Response ◽  
Random Vibration ◽  
Time History ◽  
Wide Band ◽  
Random Excitation ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
History Of ◽  
The Mean ◽  
Random Vibration Analysis

This paper presents the random vibration analysis of a simply supported cylindrical shell under a ring load which is uniform around the circumference. The time history of the excitation is assumed to be a stationary wide-band random process. The finite element method and the condition of symmetry along the length of the cylinder are used to calculate the natural frequencies and associated mode shapes. Maximum values of the mean square displacements and velocities occur at the point of application of the load. It is seen that the transient response of the shell under wide band stationary excitation is nonstationary in the initial stages and approaches the stationary solution for large value of time.

scholarly journals THE USE OF HYDROXYETHYL STARCH 200/0,5 AS PLASMA SUBTITUTES IS SAFE IN HYPOVOLEMIC PATIENTS AS INDICATED IN CHANGES OF N-ACETYL--GLUCOSAMINIDASE AND CREATININ SERUM PARAMETERS

2016 ◽  
Vol 51 (4) ◽  
pp. 228
Author(s):  
Dewi Wara Shinta ◽  
Junaidi Khotib ◽  
Eddy Rahardjo ◽  
Mahardian Rahmadi ◽  
Budi Suprapti
Keyword(s):  
Hydroxyethyl Starch ◽  
Elective Surgery ◽  
Prior History ◽  
Creatinine Ratio ◽  
Urine Creatinine ◽  
Tissue Edema ◽  
History Of ◽  
The Mean ◽  
Baseline Characteristics ◽  
Two Parameters

Hydroxyethyl Starch (HES) is a compound that improves intravascular volume effectively and rapidly without causing tissue edema. However, HES also has renal safety profile which is still being debated. Based on clinical experience in Dr. Soetomo Hospital, the frequency of acute renal failure following HES 200/0.5 administration at a dose of less than 20 ml/kg (maximum dose) is very rare. The purpose of this study was to evaluate the effect of HES 200/0.5 at a dose of less than 20 ml/kg in patients undergoing surgery. N-acetyl-b-D-Glucosaminidase (NAG) per urine creatinine ratio and creatinine serum were used as main parameter to assess renal injury. This research was observational and prospective design in patients undergoing elective surgery at Gedung Bedah Pusat Terpadu, Dr. Soetomo Hospital, who requiring resuscitation therapy with HES 200/0.5 and met the inclusion and exclusion criteria. NAG was measured prior to surgery and 12 hours after administration of fluid therapy, while creatinine serum was observed before surgery and 48 hours after resuscitation. This study was conducted for three months, and obtained 50 subjects divided into 2 groups, crystalloid group and HES 200/0.5 group. Demographic and baseline characteristics did not differ between groups, except the total bleeding volume. Total bleeding in HES 200/0.5group was higher than crystalloid group (p <0.0001). The mean volume of fluid received in HES 200/0.5 group was 2042.0 ± 673.9 mL, higher when compared with that of crystalloid group (910.0 ± 592.0 ml). Doses of HES 200/0.5 received was 8.31 ± 4.86 ml/kg. Measurement of the of NAG/creatinine ratio and creatinine serum showed significant increase in both groups, but still within the normal range. In addition, the value of these two parameters did not differ between groups. In conclusion, HES 200/0.5 in a dose of less than 20 ml/kg is safe to use in patients who suffered from hypovolemic hemorrhage, without prior history of renal impairment.

scholarly journals PHENOTYPIC EXPRESSION OF A GENETIC PROPERTY INTRODUCED BY DEOXYRIBONUCLEATE

1959 ◽  
Vol 42 (4) ◽  
pp. 737-748 ◽  
Author(s):  
Maurice S. Fox
Keyword(s):  
Standard Deviation ◽  
Time Course ◽  
Distribution Curve ◽  
Phenotypic Expression ◽  
Normal Distribution Curve ◽  
Phenotypic Alteration ◽  
The Mean ◽  
Definition Of ◽  
Two Parameters ◽  
Mean Time

The time course of the appearance of cells showing a new phenotype, following treatment with a specific DNA, has been analyzed. A plot as a function of time of the number of cells showing the new property closely resembles the summation under a normal distribution curve. Describing the appearance of the new phenotype in these terms permits the definition of two parameters, the mean time, and the standard deviation of the distribution curve. This distribution is not affected either by the DNA concentration with which the transformable population has been treated, or by the streptomycin concentration with which the transformed population has been challenged. Interruptions of the expression process, by cooling to 20° or 0°C., serve only to displace the expression curves, without changing their shape, while small reductions in temperature change both the mean time of expression and the standard deviation of the distribution curve. On the basis of these observations a number of hypotheses have been examined concerning the mechanism whereby transforming DNA manifests a phenotypic alteration in the transformed cells. It can be concluded that there exist at least two stages in the process of expression. The completion of the first stage, causing the randomization, occurs with a mean time of about 60 minutes, and a terminal step, that of the transition of phenotype, occurs in less than 3 minutes.

A Method for Inferring Conditional Stochastic Failure Rates From the Time-History of Observed Failures

2011 ◽  
Author(s):  
David Thompson ◽  
Philippe Pe´bay
Keyword(s):  
First Principles ◽  
Synthetic Data ◽  
Time History ◽  
Random Variable ◽  
Cumulative Damage ◽  
Operating Conditions ◽  
Operating Condition ◽  
History Of ◽  
Mean And Variance ◽  
The Mean

Observed failures, rather than first principles, are used to estimate fatigue rates probabilistically conditioned on operating conditions. The method developed assumes that a normal random variable may be used to approximate the damage limit (remaining lifetime) of components subjected to cumulative damage and that when a component fails, its damage limit has vanished at a rate proportional to the amount of time spent at each operating condition experienced during its lifetime. By considering differences in cumulative damage between pairs of failed components, we obtain the relative rates at which damage is accumulated for each observed operating condition. When the differences in component lifetimes are dominated by variations in experienced conditions, it is possible to estimate absolute rates. Otherwise, variations in initial damage limits dominate and it is only possible to estimate the mean and variance of this distribution. We demonstrate the procedure on synthetic data, including a test for the dominant source of lifetime variations.

scholarly journals Clinical features of episodic migraine and transformed migraine: a comparative study

2002 ◽  
Vol 60 (4) ◽  
pp. 912-916 ◽  
Author(s):  
José Carlos Busto Galego ◽  
José Paulo Cipullo ◽  
José Antonio Cordeiro ◽  
Waldir Antonio Tognola
Keyword(s):  
Time History ◽  
Episodic Migraine ◽  
Transformed Migraine ◽  
Headache Onset ◽  
Group Time ◽  
History Of ◽  
Daily Headache ◽  
Nocturnal Awakening ◽  
The Mean ◽  
Headache Patients

Transformed migraine (TM) is one of the most frequent types of chronic daily headache. Eighty patients: 40 with episodic migraine (EM) and 40 with TM with ages ranging from 18 to 60 years old were studied. Females were the majority. At first examination, the mean age was similar in both groups. The initial age of migraine attacks was significantly smaller in the TM group. Time history of episodic attacks was similar in both groups. In the EM group, the headache was predominantly located on only one side of the head; whereas in the TM group, on more than one side. There was variation in the character of pain and intensity in the TM group. Nocturnal awakening with headache, aura and family history did not show significant association with EM or TM. The TM was distinguished from the EM in relation to the frequency, location and pain intensity of the headache. Patients with early migraine headache onset may exhibit a further risk of developing TM.

Characterization and Simulation of Gunfire with Karhunen-Loeve Expansion

2004 ◽  
Vol 47 (1) ◽  
pp. 47-50
Author(s):  
David Smallwood
Keyword(s):  
Random Process ◽  
Time History ◽  
Nonstationary Random Process ◽  
Random Events ◽  
The Matrix ◽  
History Of ◽  
The Mean ◽  
Autocovariance Matrix ◽  
The Individual

Gunfire is used as an example to illustrate how the Karhunen-Loeve (K-L) expansion can be used to characterize and simulate nonstationary random events. This paper will develop a method to describe the nonstationary random process in terms of a K-L expansion. The gunfire record is broken up into a sequence of transient waveforms, each representing the response to the firing of a single round. First, the mean is estimated and subtracted from each waveform. The mean is an estimate of the deterministic part of the gunfire. The autocovariance matrix is estimated from the matrix of these single-round gunfire records. Each column is a realization of the firing of a single round. The gunfire is characterized with the K-L expansion of the autocovariance matrix. The gunfire is simulated by generating realizations of records of a single-round firing from the expansion and the mean waveform. The individual realizations are then assembled into a realization of a time history of many rounds firing. The method is straightforward and easy to implement, and produces a simulated record very much like the original measured gunfire record.

CFD Analysis of the Acoustic and Mean Flow Performance of Simple Expansion Chamber Mufflers

2004 ◽  
Author(s):  
J. M. Middelberg ◽  
T. J. Barber ◽  
S. S. Leong ◽  
K. P. Byrne ◽  
E. Leonardi
Keyword(s):  
Transmission Loss ◽  
Time History ◽  
Mean Flow ◽  
Inlet Pipe ◽  
Expansion Chamber ◽  
Acoustic Performance ◽  
Time Histories ◽  
History Of ◽  
Simple Expansion ◽  
The Mean

The acoustic and mean flow performance of different configurations of simple expansion chamber mufflers has been considered. The different configurations include extended inlet/outlet pipes and baffles inside the expansion section of the muffler. Both the acoustic and mean flow performance has been evaluated for each muffler. The acoustic CFD model of the muffler uses an axisymmetric grid with no mean flow and a single period sinusoid of suitable amplitude and duration imposed at the inlet boundary. The time history of the acoustic pressure and particle velocity are recorded at two points, one in the inlet pipe and the other in the outlet pipe. These time histories are Fourier transformed and the transmission loss of the muffler is calculated. The mean flow model of the muffler uses the same geometry, but has a finer mesh and has a suitable inlet velocity applied at the inlet boundary and the pressure drop across the muffler is found. The acoustic performance is compared with published experimental results.

Wide-Band Random Axisymmetric Vibration of Cylindrical Shells

1979 ◽  
Vol 46 (2) ◽  
pp. 417-422 ◽  
Author(s):  
I. Elishakoff ◽  
A. Th. van Zanten ◽  
S. H. Crandall
Keyword(s):  
Circular Cylindrical Shell ◽  
Time History ◽  
Wide Band ◽  
Axisymmetric Vibration ◽  
Mean Square ◽  
Mean Square Response ◽  
History Of ◽  
Cross Correlations ◽  
The Mean ◽  
Band Limited

Analytical and numerical results are reported for the random vibrations of a uniform circular cylindrical shell excited by a ring load which is uniform around the circumference and random in time. The time history of loading is taken to be a stationary wide-band random process. The shell response is essentially one-dimensional but differs qualitatively and quantitatively from the response distributions for point-excited uniform strings and beams because of the large modal overlaps at the low end of the spectrum of shell natural frequencies. The contributions from the modal cross-correlations (which can usually be neglected for strings and beams) introduce an asymmetry into the distribution of mean-square response and can alter the magnitude of the local response considerably. For example, in a thin shell with a radius-to-length ratio of 0.5 the contribution to the mean-square velocity at the driven section due to the modal cross-correlations can be more than three times that due to the modal autocorrelations when the excitation is a band-limited white noise which includes 81 modes.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

Revisiting the Natural History of Chronic Scaphoid Nonunions: A Retrospective Study of 20 Cases

2021 ◽  
Author(s):  
J. Terrence Jose Jerome
Keyword(s):  
Retrospective Study ◽  
Natural History ◽  
Functional Outcome ◽  
Grip Strength ◽  
Scaphoid Nonunion ◽  
Proximal Pole ◽  
Degenerative Arthritis ◽  
Level Of Evidence ◽  
History Of ◽  
The Mean

Abstract Background The natural history of scaphoid nonunion is the development of degenerative arthritis. A lot of information is still unclear about this progression. The purpose of this study is to analyze patients with scaphoid nonunions who had not received any kind of treatment and to assess the functional outcome. Materials and Methods This is a retrospective study that analyzed the patients with chronic scaphoid nonunions between 2009 and 2019. None of the patients received any treatment. The age at the time of injury, examination, pattern of fracture, types of scaphoid nonunion, symptoms, and duration of nonunion were noted. Diagnosis was confirmed by radiographs, computed tomography (CT) scan, and magnetic resonance imaging (MRI). Scapholunate and radiolunate angles were recorded. Pain score, modified mayo wrist score, grip strength, range of movement, and the functional outcome of these scaphoid nonunions were analyzed. A statistical correlation between the scaphoid nonunion presentations and the functional outcome was assessed. Results The mean age of the patients was 62 years (range: 35–82 years.). There were 17 male and 3 female patients. There were 9 waist and 11 proximal pole scaphoid nonunions. The mean duration of scaphoid nonunion was 34 years (range: 10–62 years). None of the patients had avascular necrosis (AVN) of the proximal scaphoid. The age at examination, gender, side of injury, fracture pattern (waist/proximal pole), fracture displacement ≤ 1 mm or > 1 mm, nonunion duration, and radiographic arthritic parameters had no significant impact on the functional outcome. Conclusions Untreated chronic scaphoid nonunion leads to the development of degenerative arthritis over a period of years, which is still unpredictable. Most of the patients become aware of the nonunion following a precedent injury or other reasons. Most of the patients have fair/good functional outcome despite reduced range of movements and grip strength. Many do not favor surgical intervention in the course of nonunion. Chronic nonunions open a lot of unanswered questions. Clinical relevance There have been numerous studies on the treatment aspects of scaphoid nonunion, with little knowledge about certain people with nonunion who did not have any kind of treatment. The demographics, clinical findings, and radiological parameters do confirm the progression of these nonunion to arthritis, but most of them had fair-to-good outcome throughout their life. It opens our thinking about the real need of treatment in such nonunions and raises numerous questions about the disease. Level of evidence This is a Level IV study.

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