scholarly journals TIMING OPTIMIZATION OF HEAD AND NECK CT ANGIOGRAPHY VIA THE INVERSE PROBLEM ALGORITHM: IN VIVO SURVEY FOR 1001 PATIENTS IN 2020–2021

2021 ◽  
Author(s):  
CHUN-CHIEH LIANG ◽  
LUNG-FA PAN ◽  
MING-HSIANG CHEN ◽  
JIE DENG ◽  
DENG-HO YANG ◽  
...  
Keyword(s):  
Inverse Problem ◽  
Correlation Coefficient ◽  
Ct Angiography ◽  
Empirical Formula ◽  
Coefficient Matrix ◽  
Biological Data ◽  
Survey Results ◽  
Matrix Formula ◽  
Semi Empirical

This study processed the recent in vivo survey results for over a thousand patients and optimized their neck and head CT angiography triggered timing (CTA-TT) via the inverse problem algorithm, which ensured the maximal ratio of both left and right arterial to upper sinuses (LRA/US). These results are instrumental in examining the ischemic stroke syndromes along the neck and head. These 1001 patients were randomly categorized into test surveyed (802 patients) and verification group (199 patients), then a six factors semi-empirical formula was constructed by the STATISTICA program. The six factors were assigned a patient’s biological data and preset of the CTA facility; namely Age, mean arterial pressure (MAP), heart rate (HR), contrast media dose (CMD), Pre (injected pressure of CMD), and body surface area (BSA). Each factor was normalized into dimensionless values and incorporated into the dataset matrix [Formula: see text] to analyze the coefficient matrix [Formula: see text]. The derived semi-empirical formula closely correlated with experimental data, according to the loss function [Formula: see text], correlation coefficient [Formula: see text], and variance of 0.8965. The formula verification for 199 more patients (verification group) yielded a correlation coefficient [Formula: see text]. Thus, it can be used for the CTA-TT estimation of patients without their preliminary tests, avoiding unnecessary irradiation. The estimated LRA/US was [Formula: see text] for the verification group in this study. A simplified three-factor formula, featuring only age, MAP, and BSA, was also proposed.

scholarly journals Changes in labial capillary density on ascent to and descent from high altitude

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2107 ◽  
Author(s):  
Edward Gilbert-Kawai ◽  
Jonny Coppel ◽  
Phillip Hennis ◽  
Michael Grocott ◽  
Can Ince ◽  
...  
Keyword(s):  
High Altitude ◽  
Correlation Coefficient ◽  
Prolonged Exposure ◽  
Haemoglobin Concentration ◽  
Capillary Density ◽  
Vessel Density ◽  
Field Of View ◽  
Rank Test ◽  
Simplified Method

Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021). There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017). Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area), despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains elevated on descent to normoxia. The technique is simple, reliable and reproducible.

scholarly journals Modification of the nuclear landscape in the inverse problem framework using the generalized Bethe–Weizsäcker mass formula

2018 ◽  
Vol 27 (02) ◽  
pp. 1850015 ◽  
Author(s):  
S. Cht. Mavrodiev ◽  
M. A. Deliyergiyev
Keyword(s):  
Inverse Problem ◽  
Mass Formula ◽  
Maximum Deviation ◽  
Model Parameters ◽  
Magic Numbers ◽  
Systems Of Equations ◽  
Nonlinear Systems Of Equations ◽  
Nuclear Mass ◽  
Nuclear Masses ◽  
Semi Empirical

We formalized the nuclear mass problem in the inverse problem framework. This approach allows us to infer the underlying model parameters from experimental observation, rather than to predict the observations from the model parameters. The inverse problem was formulated for the numerically generalized semi-empirical mass formula of Bethe and von Weizsäcker. It was solved in a step-by-step way based on the AME2012 nuclear database. The established parametrization describes the measured nuclear masses of 2564 isotopes with a maximum deviation less than 2.6[Formula: see text]MeV, starting from the number of protons and number of neutrons equal to 1.The explicit form of unknown functions in the generalized mass formula was discovered in a step-by-step way using the modified least [Formula: see text] procedure, that realized in the algorithms which were developed by Lubomir Aleksandrov to solve the nonlinear systems of equations via the Gauss–Newton method, lets us to choose the better one between two functions with same [Formula: see text]. In the obtained generalized model, the corrections to the binding energy depend on nine proton (2, 8, 14, 20, 28, 50, 82, 108, 124) and ten neutron (2, 8, 14, 20, 28, 50, 82, 124, 152, 202) magic numbers as well on the asymptotic boundaries of their influence. The obtained results were compared with the predictions of other models.

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