Statistical validation analysis between an experimental Shack-Hartmann aberrometer and a commercial device

Author(s):  
Adrian Macias-Mendoza ◽  
Juana Medina-Márquez ◽  
Juan José Raygoza-Panduro ◽  
Jaime David Rios-Arrañaga ◽  
Sandra E. Balderas-Mata
2018 ◽  
Vol 69 (7) ◽  
pp. 1830-1837
Author(s):  
Cristian Nicolescu ◽  
Alaxendru Pop ◽  
Alin Mihu ◽  
Luminita Pilat ◽  
Ovidiu Bedreag ◽  
...  

This article presents an observational randomized prospective study done on 65 patients, who underwent major surgical interventions in the field of orthopedic surgery-total hip replacement or general surgery � total colectomy. The level of albuminemia in these cases were determined before the surgical intervention, after 6 hours of the intervention and after 24 h of the intervention. The measurements of the plasmatic concentration of the pro-inflammatory cytokines Tumor Necrosis factor -alpha (TNF-alpha) and interleukin 6 (IL6) were simultaneously done with the determination of the plasmatic levels of albumin. Values of hemoglobin and hematocrit were determined 24 h after the surgical procedure in order to exclude hemodilution, which could lead to a possible drop in the levels of plasmatic albumin. After the collection of the data, the statistical work was done and it consisted of descriptive statistics, correlation and comparison tests as well as statistical validation tests. Obtained results indicate that IL-6 plays a major role comparatively with that of TNF-alfa, regarding the decrease of the plasmatic level of albumin, and due to this, the primordial cause for hypoalbuminemia is an acute hepatic phase reaction. Supplemental permeability of the capillary wall under the action of TNF alpha has a secondary role, but could lead to a faster decrease in plasmatic albumin in the first hours after the surgical procedure.


Biomimetics ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Michelle Gutiérrez-Muñoz ◽  
Astryd González-Salazar ◽  
Marvin Coto-Jiménez

Speech signals are degraded in real-life environments, as a product of background noise or other factors. The processing of such signals for voice recognition and voice analysis systems presents important challenges. One of the conditions that make adverse quality difficult to handle in those systems is reverberation, produced by sound wave reflections that travel from the source to the microphone in multiple directions. To enhance signals in such adverse conditions, several deep learning-based methods have been proposed and proven to be effective. Recently, recurrent neural networks, especially those with long short-term memory (LSTM), have presented surprising results in tasks related to time-dependent processing of signals, such as speech. One of the most challenging aspects of LSTM networks is the high computational cost of the training procedure, which has limited extended experimentation in several cases. In this work, we present a proposal to evaluate the hybrid models of neural networks to learn different reverberation conditions without any previous information. The results show that some combinations of LSTM and perceptron layers produce good results in comparison to those from pure LSTM networks, given a fixed number of layers. The evaluation was made based on quality measurements of the signal’s spectrum, the training time of the networks, and statistical validation of results. In total, 120 artificial neural networks of eight different types were trained and compared. The results help to affirm the fact that hybrid networks represent an important solution for speech signal enhancement, given that reduction in training time is on the order of 30%, in processes that can normally take several days or weeks, depending on the amount of data. The results also present advantages in efficiency, but without a significant drop in quality.


2021 ◽  
Vol 11 (13) ◽  
pp. 5999
Author(s):  
Diego A. Camacho-Hernández ◽  
Victor E. Nieto-Caballero ◽  
José E. León-Burguete ◽  
Julio A. Freyre-González

Identifying groups that share common features among datasets through clustering analysis is a typical problem in many fields of science, particularly in post-omics and systems biology research. In respect of this, quantifying how a measure can cluster or organize intrinsic groups is important since currently there is no statistical evaluation of how ordered is, or how much noise is embedded in the resulting clustered vector. Much of the literature focuses on how well the clustering algorithm orders the data, with several measures regarding external and internal statistical validation; but no score has been developed to quantify statistically the noise in an arranged vector posterior to a clustering algorithm, i.e., how much of the clustering is due to randomness. Here, we present a quantitative methodology, based on autocorrelation, in order to assess this problem.


Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.


2021 ◽  
Vol 7 ◽  
pp. 237796082098839
Author(s):  
Qian Wang ◽  
Ruifang Zhu ◽  
Zhiguang Duan

Aim To examine past Florence Nightingale Medal recipients’ parallels with the evolving nature of the nursing field as a whole. Design Descriptive research. Method The professional and demographic characteristics of 1,449 Florence Nightingale Medal recipients between 1920 and 2015 were analyzed to develop a high-level overview of the award recipient characteristics. Result Medal recipients were primarily female (98.07%), with 36% being Specialist nurses. Awards were mainly conferred for aid work (30.4%) in the context of war or armed conflict followed by Nursing education (17.2%) and disaster aid (14.9%). The majority of recipients were affiliated with the Red Cross and the majority of recipients were those conducting Red Cross duties. Conclusion Our results offer statistical validation for the dedication of these exceptional individuals, while also highlighting overall parallels with the ongoing development of the nursing field as it expands to better deliver culturally-sensitive care and to overcome outdated stereotypes that would otherwise constrain innovation.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 303
Author(s):  
Giovanni Gugliandolo ◽  
Zlatica Marinković ◽  
Giuseppe Campobello ◽  
Giovanni Crupi ◽  
Nicola Donato

Nowadays, surface acoustic wave (SAW) resonators are attracting growing attention, owing to their widespread applications in various engineering fields, such as electronic, telecommunication, automotive, chemical, and biomedical engineering. A thorough assessment of SAW performance is a key task for bridging the gap between commercial SAW devices and practical applications. To contribute to the accomplishment of this crucial task, the present paper reports the findings of a new comparative study that is based on the performance evaluation of different commercial SAW resonators by using scattering (S-) parameter measurements coupled with a Lorentzian fitting and an accurate modelling technique for the straightforward extraction of a lumped-element equivalent-circuit representation. The developed investigation thus provides ease and reliability when choosing the appropriate commercial device, depending on the requirements and constraints of the given sensing application. This paper deals with the performance evaluation of commercial surface acoustic wave (SAW) resonators by means of scattering (S-) parameter measurements and an equivalent-circuit model extracted using a reliable modeling procedure. The studied devices are four TO-39 packaged two-port resonators with different nominal operating frequencies: 418.05, 423.22, 433.92, and 915 MHz. The S-parameter characterization was performed locally around the resonant frequencies of the tested SAW resonators by using an 8753ES Agilent vector network analyzer (VNA) and a home-made calibration kit. The reported measurement-based study has allowed for the development of a comprehensive and detailed comparative analysis of the performance of the investigated SAW devices. The characterization and modelling procedures are fully automated with a user-friendly graphical user interface (GUI) developed in the Python environment, thereby making the experimental analysis faster and more efficient.


2021 ◽  
pp. 0272989X2199455
Author(s):  
Oriana Ciani ◽  
Bogdan Grigore ◽  
Hedwig Blommestein ◽  
Saskia de Groot ◽  
Meilin Möllenkamp ◽  
...  

Background Surrogate endpoints (i.e., intermediate endpoints intended to predict for patient-centered outcomes) are increasingly common. However, little is known about how surrogate evidence is handled in the context of health technology assessment (HTA). Objectives 1) To map methodologies for the validation of surrogate endpoints and 2) to determine their impact on acceptability of surrogates and coverage decisions made by HTA agencies. Methods We sought HTA reports where evaluation relied on a surrogate from 8 HTA agencies. We extracted data on the methods applied for surrogate validation. We assessed the level of agreement between agencies and fitted mixed-effects logistic regression models to test the impact of validation approaches on the agency’s acceptability of the surrogate endpoint and their coverage recommendation. Results Of the 124 included reports, 61 (49%) discussed the level of evidence to support the relationship between the surrogate and the patient-centered endpoint, 27 (22%) reported a correlation coefficient/association measure, and 40 (32%) quantified the expected effect on the patient-centered outcome. Overall, the surrogate endpoint was deemed acceptable in 49 (40%) reports ( k-coefficient 0.10, P = 0.004). Any consideration of the level of evidence was associated with accepting the surrogate endpoint as valid (odds ratio [OR], 4.60; 95% confidence interval [CI], 1.60–13.18, P = 0.005). However, we did not find strong evidence of an association between accepting the surrogate endpoint and agency coverage recommendation (OR, 0.71; 95% CI, 0.23–2.20; P = 0.55). Conclusions Handling of surrogate endpoint evidence in reports varied greatly across HTA agencies, with inconsistent consideration of the level of evidence and statistical validation. Our findings call for careful reconsideration of the issue of surrogacy and the need for harmonization of practices across international HTA agencies.


Author(s):  
Jo-Hung Yu ◽  
Hsiao-Hsien Lin ◽  
Yu-Chih Lo ◽  
Kuan-Chieh Tseng ◽  
Chin-Hsien Hsu

The present study aimed to understand Taiwanese people’s willingness to participate in the travel bubble policy. A mixed research method was used to collect 560 questionnaires, and SPSS 22.0 software was used for the statistical validation and Pearson’s performance correlation analysis. Expert opinions were collected and the results were validated using multivariate analysis. Findings: People were aware of the seriousness of the virus and the preventive measures but were not afraid of the threat of infection. They looked forward to traveling to heighten their enthusiasm, relieve stress, and soothe their emotions. However, the infection and death rates have been high, there have been various routes of infection, and it has been difficult to identify the symptoms. The complex backgrounds of people coming in and out of airports, hotels and restaurants may create pressure on the participants of events. In addition, the flawed policies and high prices resulted in a loss of confidence in the policies and a wait-and-see attitude toward tourism activities. Thus, travel decisions (0.634), physical and mental health assessment (0.716), and environmental risk (−0.130) were significantly (p < 0.05) related to travel intentions, and different issues were affected to different degrees, while health beliefs had no significant effect (p > 0.05).


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