{"title":"A Novel Method for Curvefitting the Stretched Exponential Function to Experimental Data.","authors":"Ronald K June, John P Cunningham, David P Fyhrie","doi":"10.5963/ber0204001","DOIUrl":"https://doi.org/10.5963/ber0204001","url":null,"abstract":"<p><p>The stretched exponential function has many applications in modeling numerous types of experimental relaxation data. However, problems arise when using standard algorithms to fit this function: we have observed that different initializations result in distinct fitted parameters. To avoid this problem, we developed a novel algorithm for fitting the stretched exponential model to relaxation data. This method is advantageous both because it requires only a single adjustable parameter and because it does not require initialization in the solution space. We tested this method on simulated data and experimental stress-relaxation data from bone and cartilage and found favorable results compared to a commonly-used Quasi-Newton method. For the simulated data, strong correlations were found between the simulated and fitted parameters suggesting that this method can accurately determine stretched exponential parameters. When this method was tested on experimental data, high quality fits were observed for both bone and cartilage stress-relaxation data that were significantly better than those determined with the Quasi-Newton algorithm.</p>","PeriodicalId":89747,"journal":{"name":"Biomedical engineering research","volume":"2 4","pages":"153-158"},"PeriodicalIF":0.0,"publicationDate":"2013-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3966632/pdf/nihms551202.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32219480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanping Xu, Helen C Turner, Guy Garty, David Brenner
{"title":"A Rapid, Quantitative Method to Characterize The Human Lymphocyte Concentration for Automated High-Throughput Radiation Biodosimetry.","authors":"Yanping Xu, Helen C Turner, Guy Garty, David Brenner","doi":"10.5963/ber0201002","DOIUrl":"https://doi.org/10.5963/ber0201002","url":null,"abstract":"<p><p>We have developed a Quantitative Light Absorption Analysis (QLAA) method to rapidly estimate human lymphocyte concentrations isolated from small volumes of whole blood. Measurements of the light absorption analysis were calibrated for lymphocyte concentration levels using a hemocytometer. To validate the QLAA system, blood samples were collected from 17 healthy donors and lymphocyte absorption measurements were directly compared with the manual microscope counting. The results showed that lymphocyte measurements obtained using the QLAA system were comparable with the manually scored lymphocyte counts but with measurements taken in seconds.</p>","PeriodicalId":89747,"journal":{"name":"Biomedical engineering research","volume":"2 1","pages":"16-19"},"PeriodicalIF":0.0,"publicationDate":"2013-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683596/pdf/nihms-465857.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31517897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}