Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 199
Filter
1.
Ciênc. Saúde Colet ; 26(4): 1419-1428, abr. 2021. tab
Article in English | LILACS | ID: biblio-1285924

ABSTRACT

Abstract The present study was an effort to assess the mitigation interventions carried out, so far, by the nations to fight the pandemic COVID-19. The novelty of the study was that it had considered the issue of pandemic mitigation strategy as a decision making problem. The performances of the twenty nations were to be ranked. The problem considered in the study was essentially a Multi-Criteria Decision Analysis (MCDA) problem. The available alternatives were the 20 countries and the 8 traits were the criteria. The Technique of Order Preference Similarity to the Ideal Solution (TOPSIS) was used in the present study. The study used Entropy method for assignment of weights to all the criteria. The performance score obtained in respect of the countries considered in the study and the corresponding ranks indicated the relative performances of the countries in their efforts to mitigate the COVID-19 pandemic. The results show that New Zealand is the best performing country and India is the worst one. Brazil ranked 17th, while the rank of UK was 15. The performance of the USA stood at 18th position.


Resumo O presente estudo foi um esforço para avaliar as intervenções de mitigação realizadas, até o momento, pelas nações para combater a pandemia COVID-19. A novidade do estudo é que considerou a questão da estratégia de mitigação da pandemia como um problema de tomada de decisão. As performances das vinte nações deveriam ser classificadas. O problema considerado no estudo era essencialmente um problema de Análise de Decisão Multi-Critério (MCDA). As alternativas disponíveis eram os 20 países e as 8 características eram os critérios. A Técnica de Similaridade de Preferência de Pedido com a Solução Ideal (TOPSIS) foi utilizada no presente estudo. O estudo utilizou o método da Entropia para atribuição de pesos a todos os critérios. A pontuação de desempenho obtida em relação aos países considerados no estudo e as classificações correspondentes indicaram os desempenhos relativos dos países em seus esforços para mitigar a pandemia COVID-19. Os resultados mostram que a Nova Zelândia é o país com melhor desempenho e a Índia o pior. O Brasil ficou em 17º, enquanto o Reino Unido ficou em 15. O desempenho dos EUA ficou na 18ª posição.


Subject(s)
Humans , Pandemics/prevention & control , COVID-19/prevention & control , United States/epidemiology , Brazil/epidemiology , Decision Support Techniques , Entropy , United Kingdom/epidemiology , India/epidemiology , New Zealand/epidemiology
2.
Journal of Biomedical Engineering ; (6): 1163-1172, 2021.
Article in Chinese | WPRIM | ID: wpr-921858

ABSTRACT

Entropy model is widely used in epileptic electroencephalogram (EEG) analysis, but there are few reports on how to objectively select the parameters to compute the entropy model in the analysis of resting-state functional magnetic resonance imaging (rfMRI). Therefore, an optimization algorithm to confirm the parameters in multi-scale entropy (MSE) model was proposed, and the location of epileptogenic hemisphere was taken as an example to test the optimization effect by supervised machine learning. The rfMRI data of 20 temporal lobe epilepsy (TLE) patients with hippocampal sclerosis, positive on structural magnetic resonance imaging, were divided into left and right groups. Then, the parameters in MSE model were optimized by the receiver operating characteristic curves (ROC) and area under ROC curve (AUC) values in sensitivity analysis, and the entropy value of the brain regions with statistically significant difference between the groups were taken as sensitive features to epileptogenic hemisphere lateral. The optimized entropy values of these bio-marker brain areas were considered as feature vectors input into the support vector machine (SVM). Finally, combining optimized MSE model with SVM could accurately distinguish epileptogenic hemisphere in TLE at an average accuracy rate of 95%, which was higher than the current level. The results show that the MSE model parameter optimization algorithm can accurately extract the functional imaging markers sensitive to the epileptogenic hemisphere, and achieve the purpose of objectively selecting the parameters for MSE in rfMRI, which provides the basis for the application of entropy in advanced technology detection.


Subject(s)
Brain/diagnostic imaging , Brain Mapping , Entropy , Epilepsy, Temporal Lobe/diagnostic imaging , Humans , Magnetic Resonance Imaging
3.
Article in Chinese | WPRIM | ID: wpr-921736

ABSTRACT

The potential quality markers( Q-markers) of Eupatorium lindleyanum were studied with analytic hierarchy process(AHP)-entropy weight method(EWM) and network pharmacological method. Based on the concept of Q-markers of traditional Chinese medicine, AHP-EWM was employed to quantitatively identify the Q-markers of E. lindleyanum. AHP method was applied to the weight analysis of the validity, testability, and specificity of the first-level indexes, and EWM method was used to analyze the secondlevel indexes supported by literature and experimental data. At the same time, based on the theory and method of network pharmacology, the component-target-disease-efficacy network of E. lindleyanum was built, and the components most closely related to the efficacy of resolving phlegm and relieving cough and asthma were screened out. Through the integrated analysis of the results obtained with AHP-EWM and network pharmacological method, 13 compounds including rutin, quercetin, nepetin, cirsiliol, luteolin, hyperoside,isoquercitrin, kaempferol, caffeic acid, eupalinolide K, eupalinolide A, eupalinolide B, and eupalinolide C were comprehensively identified as the potential Q-markers of E. lindleyanum. The results provide a basis for the quality control of E. lindleyanum.


Subject(s)
Analytic Hierarchy Process , Drugs, Chinese Herbal , Entropy , Eupatorium , Rutin
4.
Article in Chinese | WPRIM | ID: wpr-887941

ABSTRACT

Qixuehe Capsules is a compound Chinese patent medicine developed for treating the disorder of Qi and blood(a common etiology of gynecological disease), which has remarkable effects on smoothing liver and regulating Qi, activating blood circulation, and relieving pain. However, due to its complex prescriptions(15 herbs) and multiple effects, the quality control of Qixuehe Capsules has always been a bottleneck problem limiting its sustainable development. Therefore, this study adopted the traditional Chinese medicine Q-markers quantitative identification system established previously by our research group based on the combination of analytic hierarchy process and entropy weight methods. With the different effects of Qixuehe Capsules as the entry point, the comprehensive scores of chemical ingre-dients in Qixuehe Capsules under the items of effectiveness(smoothing liver and regulating qi, activating blood circulation, and relieving pain), testability and specificity were calculated and integrated, respectively. Subsequently, through the analysis of compatibility relationship of Qixuehe Capsules, 15 active ingredients with high comprehensive scores were found to be the top Q-mar-kers of Qixuehe Capsules, including ferulic acid, quercetin, caffeic acid, kaempferol, rutin, Z-ligustilide, senkyunolide Ⅰ, vanillic acid, protocatechuic acid, chlorogenic acid, rosmarinic acid, senkyunolide A, gallic acid, tetrahydropalmatine and eugenol. Collectively, this study not only provided scientific evidence for further research on the improvement and standardization of quality standards of Qixuehe Capsules but also provided methodological references for the quantitative identification of Q-markers of multi-effect traditional Chinese medicine formulae.


Subject(s)
Analytic Hierarchy Process , Capsules , Drugs, Chinese Herbal , Entropy , Medicine, Chinese Traditional
5.
Article in Chinese | WPRIM | ID: wpr-879159

ABSTRACT

The present work is to analyze the HPLC fingerprints of mulberry-sourced materials(Mori Ramulus, Mori Folium, Muri Cortex, Mori Fructus) using the fingerprint division total statistical moment method and information entropy, and to study the diffe-rences of the chemical components and the overall characteristics of the imprinting template in different parts of mulberry-sourced medicinal materials, so as to provide the basis for finding the effective substances in response to "homologous and different effect" of mulberry(Morus alba). The fingerprints of 24 batches of mulberry-related materials, such as Mori Ramulus, Mori Folium, Muri Cortex, Mori Fructus, were established, and the similarities and differences of the fingerprints were analyzed by calculating the division total statistical moment parameters and information entropy. The AUC_T, MCRT_T, VCRT_T and H values of 24 batches of mulberry-sourced materials were less than 0.05, with significant difference. Among them, all samples showed absorption peaks within 3-11, and 20-24 min, indicating that the four types had the identical or similar chemical composition in the same time period. After 34 min, none of the four types showed absorption peaks. Greater VCRT_T value of the fingerprints of the four kinds was observed at the retention time ranges of 3-4, 16-18, 25-27, and 31-32 min, indicating that the components of the four kinds were significantly different in these time periods; and VCRT_T value of the mulberry was significantly higher than that of the other three kinds of medicinal materials at the retention time windows of 3-4 and 15-17 min; the VCRT_T value of the mulberry white skin was significantly higher at the time windows of 8-10 and 28-30 min; the VCRT_T value of all four kinds was significantly higher within 21-23 min, indicating that the four herbs contain the same or similar components in the chromatogram during this period, but there may be significant differences between the content and the proportion. In addition, the information entropy of mulberry branches is the largest at 7-12, 23-27 min, and that of mulberry fruits is the largest at 2-8 min, which indicates that the components of mulberry branches and mulberry fruits respond greatly in the corresponding period of time, which is also the main peak period of their chemical components. For the chemical components and corresponding efficacy here. The results showed that there are significant differences in the components and contents of mulberry-sourced medicinal materials. The division total statistical moment and information entropy of the total amount of segments can be used to analyze the differences in the components of "homology and different effects", which could provide a more comprehensive analysis method for the determination of quality markers.


Subject(s)
Chromatography, High Pressure Liquid , Entropy , Fruit , Morus , Plant Leaves
6.
Article in Chinese | WPRIM | ID: wpr-879158

ABSTRACT

This research was used with high performance liquid chromatography(HPLC), combined with information entropy-response surface method(RSM) to investigate the ethanol concentration, extraction time, liquid-to-material ratio. Taking the content of four chromogens as evaluation indexes, the weight coefficients of each index were given, and the comprehensive score was calculated to optimize the extraction process. Then, prim-O-glucosylcimifugin was used as the reference, the relative calibration factors(RCFs) of cimifugin, 4'-O-β-D-glucosyl-5-O-methylvisamminol and sec-O-glucosylhamaudo to prim-O-glucosylcimifugin were calculated respectively. The contents of four components in Saposhnikoviae Radix were determined by both external standard method(ESM)and quantitative analysis of multi-components by single marker(QAMS) method, and the results were compared. At last, combined with principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA) to evaluate the quality of the Saposhnikoviae Radix in different production areas. The optimal extraction process parameter of the Saposhnikoviae Radix was as follows: liquid-to-material ratio is 60∶1(mL·g~(-1)), extraction time is 35 min, and ethanol concentration is 70%. The repeatability of the RCFs was perfect, and the results calculated by the QAMS were consistent with the results from the ESM. The stoichiometric results indicate that there are obvious differences in the distribution of Saposhnikoviae Radix in different production areas, and cimifugin and prim-O-glucosylcimifugin are the characteristic compounds that cause this difference. In this study, the optimal extraction process is stable and feasible, and the method of QAMS is accurate and reliable. From the perspective of four chromogens, there are differences in the quality of the Saposhnikoviae Radix in different production areas. Therefore, the established extraction process combined with the method of QAMS can be used to evaluate the quality of Saposhnikoviae Radix and provide a scientific basis for the quality control of Saposhnikoviae Radix.


Subject(s)
Apiaceae , Chromatography, High Pressure Liquid , Drugs, Chinese Herbal , Entropy , Plant Roots
7.
Article in Chinese | WPRIM | ID: wpr-878955

ABSTRACT

The study is aiming at investigating the application of entropy weight TOPSIS method in the comparison of the scavenging effect of DPPH, ABTS and hydroxyl radical and the inhibition effect of xanthine oxidase(XOD) and lipoxygenase(LOX) of Chrysanthemum indicum. The DPPH, ABTS, salicylic acid and spectrophotometry were used to determine the scavenging effect of DPPH, ABTS and hydroxyl radical and the inhibition effect of xanthine oxidase(XOD) and lipoxygenase(LOX) of Ch. indicum from 31 different areas in vitro. Take the half inhibition rate of as the evaluation index, two principal components were extracted by the principal component analysis, and their cumulative contribution rate reached at 92.4%. The different areas of Ch. indicum could be divided into Dabei Mountain and Qinling-Taihang Mountain by use principal component to analysis. The entropy weight TOPSIS method was used to objectively assign weights to five indexes, calculate the weight of each index and set up the best and worst scheme of the evaluation object, and the relative proximity(C_i) was used as the measure to construct the multi-index comprehensive evaluation model of Ch. indicum. And then sort with the relative proximity value. The results showed that the relative proximity was between 0.098 and 0.983 which represents there were significant differences in the scavenging effect of DPPH, ABTS and hydroxyl radical and the inhibition effect of xanthine oxidase(XOD) and lipoxygenase(LOX) between extracts of Ch. indicum from different areas. The Ch. indicum from Dabie Mountain area have a relatively high relative degree of measurement and high-quality ranking. Taken together, the quality of Ch. indicum.from the Dabie Mountain area is better. The index weight coefficient and the classification result of producing area are basically consistent with the result of principal component analysis. The results show that the TOPSIS method based on entropy weight method can be used to evaluate the comprehensive quality of Ch. indicum.


Subject(s)
Anti-Inflammatory Agents , Antioxidants , Chrysanthemum , Entropy , Plant Extracts
8.
Rev. colomb. anestesiol ; 48(3): 111-117, July-Sept. 2020. tab, graf
Article in English | LILACS, COLNAL | ID: biblio-1126292

ABSTRACT

Abstract Introduction: Total intravenous anesthesia (TIVA) and balanced anesthesia (BA) are the most commonly used anesthetic techniques. The differences are the variability of the depth of anesthesia between these techniques that might predict which one is safer for patients and presents a lower risk of intraoperative awakening. Objective: To determine whether a difference exists in the variability of depth of anesthesia obtained by response entropy (RE). Methods: A crossover clinical trial was conducted on 20 healthy patients receiving upper or lower limb ambulatory orthopedic surgery. Patients were randomly assigned to (a) target-controlled infusion of propofol using the Schnider model at a target concentration of 2.5 µg/mL for 15 minutes and a 10-minute washout, followed by sevoflurane administration at 0.8 minimal alveolar concentration (MAC) for the reminder of the surgery, or (b) the reverse sequence. Differences in the variability of the depth of anesthesia using RE were evaluated using paired t-test. Results: The treatment effect showed no significant difference in the average values of RE, during TIVA = 97.23 vs BA 97.04 (P = 0.39). Carry Over (-4.98 vs 4.08) and Period (100.3 vs 94.68) effects were not significantly different. Conclusion: The present study suggests that both anesthetic techniques are equivalent in terms of the stability of the depth of anesthesia. It is important to keep testing the determinants of the efficacy of different populations because the individual behaviors of patients might ultimately tip the scale.


Resumen Introducción: La anestesia total intravenosa (TIVA, por sus siglas en inglés) y la anestesia balanceada (AB) son las técnicas anestésicas más comúnmente utilizadas. La diferencia está en la variabilidad de la profundidad de la anestesia entre estas dos técnicas, lo cual pudiera predecir cuál es más segura para los pacientes y representar un menor riesgo de despertar intraoperatorio. Objetivo: Determinar si existe alguna diferencia en la variabilidad de la profundidad de la anestesia obtenida según los índices de entropía de respuesta (ER). Métodos: Se llevó a cabo un estudio clínico cruzado en 20 pacientes sanos que se sometieron a cirugía ortopédica ambulatoria de miembros superiores o inferiores. Los pacientes se asignaron aleatoriamente así: a) infusión controlada por objetivo (TCI, por sus siglas en inglés) de propofol, utilizando el modelo Schnider a una concentración objetivo de 2,5 µg/mL durante 15 min y un período de lavado de 10 minutos, seguido de la administración de sevoflurano a 0,8 de concentración alveolar mínima (CAM) durante el tiempo restante de la cirugía; o b) la secuencia inversa. Las diferencias en la variabilidad de la profundidad de la anestesia utilizando entropía de respuesta se evaluaron utilizando la prueba t pareada. Resultados: El efecto del tratamiento no mostró ninguna diferencia significativa en los valores promedio de entropía de respuesta (ER) durante TIVA = 97,23 vs. AB 97,04 (P = 0,39). Los efectos de arrastre (-4,98 vs. 4,08) y período (100,3 vs. 94,68) no fueron significativamente diferentes. Conclusiones: El presente estudio sugiere que ambas técnicas anestésicas son equivalentes en términos de estabilidad de la profundidad de la anestesia. Es importante continuar probando los factores determinantes de eficacia en las distintas poblaciones, ya que el comportamiento individual de cada paciente pudiera finalmente inclinar la balanza.


Subject(s)
Humans , Male , Female , Adult , Entropy , Intraoperative Awareness , Balanced Anesthesia , Anesthesia, Intravenous , Propofol , Epidemiologic Methods , Sevoflurane
9.
Article in Chinese | WPRIM | ID: wpr-828014

ABSTRACT

Using the 260 geographical distribution records of Polygonatum cyrtonema in China, combined with 53 environmental factors, the maximum entropy modeling(MaxEnt) was used to study the ecological factors affecting the suitability distribution of P. cyrtonema. The ArcGIS software was used to predict the potential distribution of the population of P. cyrtonema. The dominant factors were chosen by using the Jackknife test and the Receiver Operating Characteristic(ROC) curve was used to evaluate the simulation. The results showed that high value of area under curve(AUC) denoted good results, which significantly differed from random predictions. Based on the evaluation criterion, the accuracies of the predictions of P. cyrtonema potential distribution in the current periods were excellent. The main environmental factors affecting the suitable growth of P. cyrtonema were the monthly precipitation, the wettest monthly precipitation, the annual average temperature range and the precipitation of November, March, February, April, May and October. There are 9 environmental factors in soil type. The potential fitness of P. cyrtonema in China is high, mainly concentra-ted in Hunan, western Hubei, Guangdong, northeastern Guangxi, southeastern Guizhou, Jiangxi, southwestern Anhui, Fujian, Zhejiang, Shaanxi, southwestern Henan and Chongqing. The growth distribution of the potential distribution area of P. cyrtonema was divided, and the zoning map of the growth suitability of P. cyrtonema was formed. Through the comparative analysis of the potential distribution range based on MaxEnt and the distribution range of literature records, the understanding of the distribution range of P. cyrtonema was expanded.


Subject(s)
China , Ecology , Entropy , Polygonatum , Research Design , Soil
10.
Article in Chinese | WPRIM | ID: wpr-878830

ABSTRACT

To optimize the ethanol extraction technology parameters of Fengyin Decoction by orthogonal experiment combined with beetle antennae search(BAS)-genetic algorithm(GA)-back propagation neural network(BPNN). Based on single factor investigation, the extraction temperature, ethanol volume, extraction time, and ethanol concentration were used as orthogonal experiment factors, and entropy weight method was used to calculate the comprehensive scores of aloe-emodin, glycyrrhizic acid ammonium salt, rhein, emodin, chrysophanol, physcion, cinnamaldehyde, 6-gingerol, extraction ratio and fingerprint similarity. BAS-BPNN model was established, and then, GA was used to predict the optimal extraction process. The results showed that BAS-BPNN was optimized to obtain the optimal ethanol extraction process of Fengyin Decoction as follows: extraction temperature of 87 ℃, adding 9 times of 75 % ethanol, and extracting for 47 minutes, with a comprehensive score of 1.052 9. Meanwhile, the optimal process parameters obtained by orthogonal design were as follows: the extraction temperature of 80 ℃, adding 10 times of 75% ethanol, extracting for 30 minutes, with a comprehensive score of 1.003 7. The comprehensive score of the process obtained from the BAS-BPNN model was slightly better than that from the orthogonal test, indicating that the optimized process from BAS-BPNN model was more ideal, so it was finally determined as the best extraction process for Fengyin Decoction. The process of Fengyin Decoction obtained from BAS-GA-BPNN has high extraction efficiency and good stability, which provides reference for the subsequent development and quality control.


Subject(s)
Drugs, Chinese Herbal , Entropy , Ethanol , Neural Networks, Computer , Quality Control
11.
Article in Chinese | WPRIM | ID: wpr-878806

ABSTRACT

In order to discuss the "entropy weight method" for weighting various indicators in the comprehensive evaluation of Angelicae Sinensis Radix slices(ASR), the quality of ASR was comprehensively evaluated by entropy weight-based gray systematic theory and cluster analysis. In this study, the contents of ferulic acid, volatile oil, polysaccharide, alcohol extract, water extract, moisture, total ash and acid-insoluble ash in 44 batches of ASR from different sources were determined. The entropy weight method was used for objective weighting. With relative correlation(r_i) as a measure, a multi-index comprehensive evaluation model was constructed for the quality of ASR. The results showed that the relative correlation value of 44 batches of ASR ranged from 0.301 9 to 0.662 9. There were certain differences in the quality of ASR from different sources. The ASR S1-S8, traceable and standardized in processing techno-logy, showed a high relative correlation degree and high quality ranking, indicating that the implementation of systemic management of the production chain of Chinese herbal pieces was beneficial to the quality control of ASR. The quality evaluation results of 44 batches of ASR were consistent with those of traditional geo-authentic habitats for ASR and the mainstream varieties of ASR on market, and basically consistent with the results of cluster analysis. This study suggests that the gray systematic theory based on the entropy weighting method can be used for the quality evaluation of ASR. The objective weighting of the entropy weight method improves the reliability of the gray correlation method and the scientificity of ASR quality evaluation.


Subject(s)
Angelica sinensis , Drugs, Chinese Herbal , Entropy , Oils, Volatile , Plant Roots , Reproducibility of Results
12.
Rev. bras. cir. cardiovasc ; 34(5): 572-580, Sept.-Oct. 2019. tab, graf
Article in English | LILACS | ID: biblio-1042041

ABSTRACT

Abstract Objective: To characterize the behavior of cardiac autonomic modulation in individuals with different times after orthotopic heart transplantation (HTx) using symbolic dynamics analysis. Methods: Sixty patients were evaluated after HTx. We recorded their instantaneous R-R intervals (RRi) by cardiac monitor Polar® RS800CX™ (Polar Electro Oy, Kempele, Finland) for 10 minutes. The same sequence of RRi with 256 consecutive beats was used to perform spectral analysis and symbolic dynamics analysis. We used hierarchical clustering to form groups. One-way analysis of variance (ANOVA) (with Holm-Sidak method) or one-way Kruskal-Wallis test (with Dunn´s post-hoc test) was used to analyze the difference between groups. Linear correlation analysis between variables was performed using Pearson's or Spearman's tests. P-value < 0.05 was considered statistically significant. Results: The 0V% index increased, the 2UV% index and the normalized complexity index decreased with an increase of HTx postoperative time. There were a negative correlation between complexity indexes and 0V% and a positive correlation between complexity indexes and 2UV%. Conclusion: Symbolic dynamics indexes were able to show a specific cardiac autonomic modulation pattern for HTx recipients with different postoperative times.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Parasympathetic Nervous System/physiopathology , Sympathetic Nervous System/physiopathology , Heart Transplantation/rehabilitation , Nonlinear Dynamics , Heart/physiopathology , Postoperative Period , Reference Values , Time Factors , Linear Models , Cross-Sectional Studies , Retrospective Studies , Analysis of Variance , Statistics, Nonparametric , Entropy , Heart Rate/physiology
13.
Rev. cuba. inform. méd ; 11(1)ene.-jun. 2019.
Article in Spanish | LILACS, CUMED | ID: biblio-1093310

ABSTRACT

El análisis estadístico implicativo es una técnica de minería de datos, surgida para resolver problemas de la didáctica de las matemáticas, se basa en la inteligencia artificial y el álgebra booleana, para modelar la casi implicación entre eventos y variables de un conjunto de datos. El objetivo de este ensayo es exponer las evidencias teóricas y prácticas que demuestran su utilidad para el estudio de la causalidad en la salud, para lo cual se realizó una revisión exhaustiva del tema en las bases de datos bibliográficas alojadas en Internet. Se presentan una serie de razones que justifican el uso de esta técnica en estudios de causalidad en medicina, en relación con el número de variables, el tamaño de la muestra, los supuestos requeridos para su aplicación y la naturaleza asimétrica de sus índices. También se identifican algunas ventajas con respecto a las técnicas estadísticas tradicionales, como la detección de eventos raros, que pasan inadvertidos a medidas como el apoyo y la confianza. Finalmente, se mencionan las investigaciones clínico-epidemiológicas donde se ha utilizado este análisis(AU)


Implicative statistical analysis is a technique of data mining, emerged to solve problems of the Didactic of mathematics, it is based on Artificial Intelligence and Boolean Algebra, to model the quasi-implication between events and variables of a data set. The objective of this essay is to expose the theoretical and practical evidences that demonstrate its utility for the study of causality in health, for which an exhaustive review of the subject was carried out in the bibliographic databases hosted on the internet. A series of reasons are presented that justify the use of this technique in causality studies in medicine, regarding the number of variables, the sample size, the assumptions required for its application and the asymmetric nature of its indices. Also some advantages are identified with respect to traditional statistical techniques such as detection of rare events, which would go unnoticed to measures such as support and trust. Finally, clinical-epidemiological investigations where this analysis has been used are mentioned(AU)


Subject(s)
Artificial Intelligence , Statistical Analysis , Causality , Entropy
14.
Article in English | WPRIM | ID: wpr-764985

ABSTRACT

BACKGROUND: Most depth of anesthesia (DOA) monitors rely on the temporal characteristics of a single-channel electroencephalogram (EEG) and cannot provide spatial or connectivity information. Phase lag entropy (PLE) reflects DOA by calculating diverse connectivity from temporal patterns of phase relationships. The aim of this study was to compare the performance of PLE and bispectral index (BIS) monitors for assessing DOA during anesthesia induction, nerve integrity monitoring (NIM), and anesthesia emergence. METHODS: Thirty-five patients undergoing elective thyroid surgery with recurrent laryngeal nerve NIM received propofol and remifentanil via target-controlled infusion. After applying PLE and BIS monitors, propofol infusion was initiated at a calculated effect site concentration (Ce) of 2 µg/mL and then increased in 1-µg/mL Ce increments. After propofol Ce reached 5 μg/mL, a remifentanil infusion was begun, and anesthesia induction was considered complete. During NIM, PLE and BIS values were compared at a specific time points from platysma muscle exposure to subcutaneous tissue closure. PLE and BIS values were recorded continuously from preanesthetic state to full recovery of orientation; bias and limits of agreement between monitors were calculated. RESULTS: PLE and BIS values decreased progressively with increasing propofol Ce during anesthetic induction and increased by stages during emergence. The prediction probabilities of PLE and BIS for detecting propofol Ce changes were 0.750 and 0.756, respectively, during induction and 0.749 and 0.746, respectively, during emergence. No aberrant PLE or BIS values occurred during NIM. Correlation coefficients for BIS and PLE were 0.98 and 0.92 during induction and emergence, respectively. PLE values were significantly higher than BIS values at full recovery of orientation. Estimated bias between monitors was −4.16 ± 8.7, and 95% limits of agreement were −21.21 to 12.89. CONCLUSION: PLE is a reasonable alternative to BIS for evaluating consciousness and DOA during general anesthesia and during NIM. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0003490


Subject(s)
Anesthesia , Anesthesia, General , Bias , Consciousness , Consciousness Monitors , Electroencephalography , Entropy , Humans , Information Services , Propofol , Recurrent Laryngeal Nerve , Subcutaneous Tissue , Superficial Musculoaponeurotic System , Thyroid Gland
15.
Article in Chinese | WPRIM | ID: wpr-774222

ABSTRACT

The early diagnosis of children with autism spectrum disorders (ASD) is essential. Electroencephalography (EEG) is one of most commonly used neuroimaging techniques as the most accessible and informative method. In this study, approximate entropy (ApEn), sample entropy (SaEn), permutation entropy (PeEn) and wavelet entropy (WaEn) were extracted from EEGs of ASD child and a control group, and Student's -test was used to analyze between-group differences. Support vector machine (SVM) algorithm was utilized to build classification models for each entropy measure derived from different regions. Permutation test was applied in search for optimize subset of features, with which the SVM model achieved best performance. The results showed that the complexity of EEGs in children with autism was lower than that of the normal control group. Among all four entropies, WaEn got a better classification performance than others. Classification results vary in different regions, and the frontal lobe showed the best performance. After feature selection, six features were filtered out and the accuracy rate was increased to 84.55%, which can be convincing for assisting early diagnosis of autism.


Subject(s)
Algorithms , Autism Spectrum Disorder , Classification , Diagnosis , Child , Electroencephalography , Entropy , Humans , Support Vector Machine
16.
Article in Chinese | WPRIM | ID: wpr-774175

ABSTRACT

Atrial fibrillation (AF) is one of the most common arrhythmias, which does great harm to patients. Effective methods were urgently required to prevent the recurrence of AF. Four methods were used to analyze RR sequence in this paper, and differences between Pre-AF (preceding an episode of AF) and Normal period (far away from episodes of AF) were analyzed to find discriminative criterion. These methods are: power spectral analysis, approximate entropy (ApEn) and sample entropy (SpEn) analysis, recurrence analysis and time series symbolization. The RR sequence data used in this research were downloaded from the Paroxysmal Atrial Fibrillation Prediction Database. Supporting vector machine (SVM) classification was used to evaluate the methods by calculating sensitivity, specificity and accuracy rate. The results showed that the comprehensive utilization of recurrence analysis parameters reached the highest accuracy rate (95%); power spectrum analysis took second place (90%); while the results of entropy analyses and time sequence symbolization were not satisfactory, whose accuracy were both only 70%. In conclusion, the recurrence analysis and power spectrum could be adopted to evaluate the atrial chaotic state effectively, thus having certain reference value for prediction of AF recurrence.


Subject(s)
Atrial Fibrillation , Diagnosis , Entropy , Heart Atria , Humans , Recurrence , Sensitivity and Specificity , Support Vector Machine
17.
Article in Chinese | WPRIM | ID: wpr-773495

ABSTRACT

OBJECTIVE@#To compare the effectiveness and sensitivity of entropy and regional homogeneity (ReHo) for identifying irritable bowel syndrome (IBS) based on functional magnetic resonance imaging (fMRI).@*METHODS@#Voxel-based approximate entropy (ApEn) was calculated based on findings of resting fMRI of 54 patients with IBS and 54 healthy control subjects. Feature selection was performed using independent sample -test, and support vector machine was then used to classify and identify different groups. The classification performance obtained from ApEn was compared with that from ReHo.@*RESULTS@#Significant differences between the two groups were found in the left triangle part of inferior prefrontal gyrus, right angular gyrus of the inferior parietal lobule, left inferior temporal gyrus, left middle temporal gyrus, left lingual gyrus, bilateral middle occipital gyrus and bilateral superior occipital gyrus for ReHo ( < 0.05), and in the bilateral postcentral gyrus, right precentral gyrus, right inferior temporal gyrus, bilateral middle temporal gyrus and left superior occipital gyrus for ApEn ( < 0.05). ApEn consistently showed better performance than ReHo regardless of the variations in the number of features. The classification accuracy, specificity and sensitivity of ApEn were 93.5185%, 90.7407% and 96.2963%, respectively, as compared with 86.1111%, 85.1852% and 87.037% of ReHo.@*CONCLUSIONS@#Entropy analysis based on fMRI can be more sensitive and effective than ReHo for identification of IBS.


Subject(s)
Brain , Diagnostic Imaging , Brain Mapping , Case-Control Studies , Entropy , Humans , Irritable Bowel Syndrome , Diagnostic Imaging , Magnetic Resonance Imaging
18.
Article in English | WPRIM | ID: wpr-759549

ABSTRACT

BACKGROUND: Phase-lag entropy (PLE) was recently described as a measurement of temporal pattern diversity in the phase relationship between two electroencephalographic signals from prefrontal and frontal montages. This study was performed to evaluate the performance of PLE for assessing the depth of sedation. METHODS: Thirty adult patients undergoing upper limb surgery with a brachial plexus block were administered propofol by target-controlled infusion. The depth of sedation was assessed using the Observer's Assessment of Alertness/Sedation (OAA/S) scale. The effect-site concentration (Ce) of propofol was initially started at 0.5 μg/ml and was increased in increments of 0.2 μg/ml until an OAA/S score of 1 was reached. Three minutes after the target Ce was reached, the PLE, bispectral index (BIS), and level of sedation were assessed. Correlations between the OAA/S score and PLE or BIS were determined. The prediction probabilities (P(k)) of PLE and BIS were also analyzed. RESULTS: The PLE values were closely correlated with the OAA/S scores (Spearman's Rho = 0.755; P < 0.001) to an extent comparable with the correlation between the BIS and OAA/S score (Spearman's Rho = 0.788; P < 0.001). The P(k) values of PLE and BIS were 0.731 and 0.718, respectively. CONCLUSIONS: PLE is a new and reliable consciousness monitoring system for assessing the depth of sedation induced by propofol, which is comparable with the BIS.


Subject(s)
Adult , Brachial Plexus Block , Consciousness Monitors , Electroencephalography , Entropy , Humans , Propofol , Upper Extremity
19.
Article in English | WPRIM | ID: wpr-719535

ABSTRACT

BACKGROUND: The aortic knob width (AKW) and the heart rate variability (HRV) were suggested to be related to development of cardiovascular diseases. However, the relationship between them has not been investigated; thus, this study aimed to determine this relationship. METHODS: This study included 587 Koreans aged 18–79 years. Their physical measurements, medical and social histories, blood test findings, and chest radiographs were obtained. The HRV parameters included the standard deviation of the N-N interval (SDNN), root mean square of successive differences (RMSSD), approximate entropy (ApEn), total power (TP), very low frequency (VLF), low frequency (LF), high frequency (HF), and LF/HF ratio, which were measured for 5 minutes. The AKW was measured on chest radiographs by a single reviewer. RESULTS: The AKW was significantly correlated with the HRV parameters, except for the LF/HF ratio. However, RMSSD and ApEn were not significantly related to the AKW in women. After dividing the participants into quartile groups, the AKW was significantly related to the SDNN, RMSSD, TP, VLF, LF, and HF. The HRV parameter values decreased in the higher AKW quartile groups, the HRV parameter values decreased. After adjusting for sex, drinking status, exercise habits, smoking status, waist circumference, and triglyceride, low-density lipoprotein cholesterol, fasting blood sugar, and glycated hemoglobin levels, the AKW showed significant negative associations with the HRV parameters, except for the LF/HF ratio. CONCLUSION: The AKW is significantly associated with the HRV parameters of SDNN, RMSSD, ApEn, TP, VLF, LF, and HF.


Subject(s)
Aorta, Thoracic , Blood Glucose , Cardiovascular Diseases , Cholesterol , Drinking , Entropy , Fasting , Female , Heart Rate , Heart , Hematologic Tests , Glycated Hemoglobin A , Humans , Lipoproteins , Radiography, Thoracic , Smoke , Smoking , Triglycerides , Waist Circumference
20.
Article in English | WPRIM | ID: wpr-741444

ABSTRACT

OBJECTIVE: To evaluate whether computed tomography (CT) reconstruction algorithms affect the CT texture features of the liver parenchyma. MATERIALS AND METHODS: This retrospective study comprised 58 patients (normal liver, n = 34; chronic liver disease [CLD], n = 24) who underwent liver CT scans using a single CT scanner. All CT images were reconstructed using filtered back projection (FBP), hybrid iterative reconstruction (IR) (iDOSE4), and model-based IR (IMR). On arterial phase (AP) and portal venous phase (PVP) CT imaging, quantitative texture analysis of the liver parenchyma using a single-slice region of interest was performed at the level of the hepatic hilum using a filtration-histogram statistic-based method with different filter values. Texture features were compared among the three reconstruction methods and between normal livers and those from CLD patients. Additionally, we evaluated the inter- and intra-observer reliability of the CT texture analysis by calculating intraclass correlation coefficients (ICCs). RESULTS: IR techniques affect various CT texture features of the liver parenchyma. In particular, model-based IR frequently showed significant differences compared to FBP or hybrid IR on both AP and PVP CT imaging. Significant variation in entropy was observed between the three reconstruction algorithms on PVP imaging (p 0.75) for CT imaging without filtration. CONCLUSION: CT texture features of the liver parenchyma evaluated using the filtration-histogram method were significantly affected by the CT reconstruction algorithm used.


Subject(s)
Entropy , Filtration , Humans , Liver Diseases , Liver , Methods , Retrospective Studies , Tomography, X-Ray Computed
SELECTION OF CITATIONS
SEARCH DETAIL