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BackgroundSystematic reviews and their implementation in practice provide high quality evidence for clinical practice but are both time and labor intensive due to the large number of articles. Automatic text classification has proven to be instrumental in identifying relevant articles for systematic reviews. Existing approaches use machine learning model training to generate classification algorithms for the article screening process but have limitations. ObjectiveWe applied a network approach to assist in the article screening process for systematic reviews using predetermined article relationships (similarity). The article similarity metric is calculated using the MEDLINE elements title (TI), abstract (AB), medical subject heading (MH), author (AU), and publication type (PT). We used an article network to illustrate the concept of article relationships. Using the concept, each article can be modeled as a node in the network and the relationship between 2 articles is modeled as an edge connecting them. The purpose of our study was to use the article relationship to facilitate an interactive article recommendation process. MethodsWe used 15 completed systematic reviews produced by the Drug Effectiveness Review Project and demonstrated the use of article networks to assist article recommendation. We evaluated the predictive performance of MEDLINE elements and compared our approach with existing machine learning model training approaches. The performance was measured by work saved over sampling at 95% recall (WSS95) and the F-measure (F1). We also used repeated analysis over variance and Hommel’s multiple comparison adjustment to demonstrate statistical evidence. ResultsWe found that although there is no significant difference across elements (except AU), TI and AB have better predictive capability in general. Collaborative elements bring performance improvement in both F1 and WSS95. With our approach, a simple combination of TI+AB+PT could achieve a WSS95 performance of 37%, which is competitive to traditional machine learning model training approaches (23%-41% WSS95). ConclusionsWe demonstrated a new approach to assist in labor intensive systematic reviews. Predictive ability of different elements (both single and composited) was explored. Without using model training approaches, we established a generalizable method that can achieve a competitive performance.

BackgroundThe Unified Medical Language System (UMLS) contains many important ontologies in which terms are connected by semantic relations. For many studies on the relationships between biomedical concepts, the use of transitively associated information from ontologies and the UMLS has been shown to be effective. Although there are a few tools and methods available for extracting transitive relationships from the UMLS, they usually have major restrictions on the length of transitive relations or on the number of data sources. ObjectiveOur goal was to design an efficient online platform that enables efficient studies on the conceptual relationships between any medical terms. MethodsTo overcome the restrictions of available methods and to facilitate studies on the conceptual relationships between medical terms, we developed a Web platform, onGrid, that supports efficient transitive queries and conceptual relationship studies using the UMLS. This framework uses the latest technique in converting natural language queries into UMLS concepts, performs efficient transitive queries, and visualizes the result paths. It also dynamically builds a relationship matrix for two sets of input biomedical terms. We are thus able to perform effective studies on conceptual relationships between medical terms based on their relationship matrix. ResultsThe advantage of onGrid is that it can be applied to study any two sets of biomedical concept relations and the relations within one set of biomedical concepts. We use onGrid to study the disease-disease relationships in the Online Mendelian Inheritance in Man (OMIM). By crossvalidating our results with an external database, the Comparative Toxicogenomics Database (CTD), we demonstrated that onGrid is effective for the study of conceptual relationships between medical terms. ConclusionsonGrid is an efficient tool for querying the UMLS for transitive relations, studying the relationship between medical terms, and generating hypotheses.

Using 5 grades of conventional cigarette finished tobacco as the research object, multiple linear regression analysis method was used to study the influence of physical indicators of cut tobacco on its rebound characteristics, and a prediction model for tobacco rebound characteristics based on BP neural network was constructed. The results showed that the degree of influence of physical indicators of cut tobacco on the rebound characteristics of tobacco was ranked from large to small as follows: broken tobacco rate>medium tobacco rate>long tobacco rate>filling value>elasticity>moisture content. Among them, medium tobacco rate, long tobacco rate, elasticity, and moisture content were positively correlated with the rebound characteristics of tobacco, while broken tobacco rate and filling value were negatively correlated with the rebound characteristics of tobacco. In the constructed BP neural network prediction model, the comparison between the predicted value of the test set and the true value R² was 0.965 7, the overall model accuracy reached 98. 10%. The difference between the predicted and measured values of cut tobacco rebound characteristics was small, and the model had high prediction accuracy and reliability, which could be used for accurate estimation of cut tobacco rebound characteristics. [ABSTRACT FROM AUTHOR]

Thermogravimetry was used to reveal the pyrolysis differences of tobacco stems in different storage years in Henan, Hunan and Guizhou. The surface structure, pyrolysis characteristics and gaseous product composition of tobacco stems in different storage years in Henan were analyzed by electron microscopy and the IG-FTIR instrument,and the difference of kinetic parameters in each weight loss stage of stem in different years during the pyrolysis were compared and analyzed based on the Coats-Redfern method. The results showed that the effects of different storage years on the thermal weight-loss behavior of tobacco stems from Henan, Hunan and Guizhou were similar. The CPI value of tobacco stems stored for 1 year (1. 27-1. 39x10-4%-min-1--2) was higher than that of tobacco stems stored for 2 and 3 years, indicating good pyrolysis characteristics; the residual rate of tobacco stems stored for 3 years was 18. 18%-27. 45%, with poor thermal stability. While the types of pyrolysis gas products released by tobacco stems in different storage years in Henan were similar, and the maximum gas product release rate was shown as follows: tobacco stems stored for 3 years> those stored for 2 years> those stored for 1 year, and the integrity of the surface structure of tobacco stem was poor after 3 years storage, the main weight loss stages during the thermal decomposition of different storage years tobacco stem was mainly controlled by a 1. 5-order chemical reaction model. [ABSTRACT FROM AUTHOR]

To determine the suitable packing density in cases during off-site delivery of cut tobacco, the bulk density and deposition density of blended cut tobacco and its constituents under different conditions were measured. The variations of quality and making quality of cut tobacco at different packing densities in cases were comparatively analyzed, and the results showed that: 1) When the packing density of cut tobacco was less than the vibrated deposition density, the effects on the filling value and elasticity of the off-site delivered blended cut tobacco were minor. 2) With the increase of the packing density, before and after the delivery, the changes in moisture contents in cut tobacco decreased generally, the changes in filling values increased generally, the changes of integral strand proportions and short strand proportions decreased first and then increased; loss of tobacco from the ends of cigarette decreased first and then increased, the dust contents in manufactured cigarettes increased generally, and the consistency of sensory quality was improved to some extents. 3) Cut tobacco packed in cases suffered sagging during delivery, the inflection point with large changes in the quality indexes and consumption was mostly at the vibrated deposition density. In order to coordinate the quality and cost of off-site delivery of cut tobacco, the packing density should not be higher than the vibrated deposition density of cut tobacco. [ABSTRACT FROM AUTHOR]

In order to study the relationships between shatter resistance index and physical characteristics of tobacco leaves, correlation analysis, factor analysis, and gray correlation analysis were carried out on the tobacco leaves shatter resistance index and physical characteristics index, and the tobacco leaves of different regions were grouped according to the analysis results. The result showed as follows: shatter resistance index of tobacco leaves was significantly positively correlated with tensile strength, elongation, recovery, and thickness, and significantly negatively correlated with brittleness, shear force, cohesion, elasticity, adhesion, and penetration. Fac-1 (determined by tensile strength, cohesion, elasticity, recovery, adhesion, penetration), Fac-2 (determined by shear force, thickness), Fac-3(determined by elongation, brittleness and hardness) and Fac-4 (determined by adhesion) common factors were extracted from 12 physical characteristics, and the cumulative contribution rate was 88. 201%, the contribution rate of Fac-1 is significantly higher than the other three common factors, indicating that Fac-1 had the most significant impact. According to the contribution rate of the common factors and the factor score coefficient matrix, the comprehensive factor score model of the physical characteristics of tobacco leaf was established as F = 0.46FFac-1 +0.23FFac-2 +0.20FFac-3 +0.11FFac-4. Fac-3 had the greatest impact on the shatter resistance index of tobacco leaves, and Fac-4 had the least impact. According to cluster analysis, the tobacco leaves were divided into 4 categories, so that the comprehensive physical characteristics of the same category of tobacco leaves were closer, and the process parameters could be adjusted and processed into groups to reduce the breaking of tobacco leaves during processing. [ABSTRACT FROM AUTHOR]

A quantitative characterization method of tobacco stem re-permeability was established by texture analyzer, and the best instrument test parameters were determined. The method was used to characterize the degree of tobacco stem re-premeability under different regions, specifications and moisture regain parameters. The results showed that the best test parameters: the probe model was HDP/BSK shear type probe, the probe's pre-test, test and return speed was 5. 0 mm/s, 1. 0 mm/s, 5. 0 mm/s, respectively trigger force was 15 g, and strain was 170%; the intra-day and inter-day precisions were 6. 44% and 4. 26%, indicating that this quantitative characterization method had high precision and good repeatability, which could objectively evaluate the degree of re-permeability of tobacco stem. There were some differences in the degree of re-permeability of tobacco stem in different regions. The degree of re-permeability of tobacco stem was lowest in Sanmenxia, He'nan, and highest in Qianxi'nan. The degree of re-permeability of tobacco stem decreased with the increase of the stem length and diameter, increased with the increase of stem washing time and water temperature, and increased first and then decreased with the increase of stem storage time. Place of origin, stem washing time, water temperature, stem storage time, and the interaction between place of origin and stem storage time had a very significant impact on the degree of tobacco stem re-permeability, but the interaction between place of origin and stem washing time and water temperature was not significant. [ABSTRACT FROM AUTHOR]

In order to comprehensively evaluate the ash integration and cohesion of statically burning i.e., smoldering cigarettes based on cigarette paper parameters, the correlations between cigarette paper parameters and cigarette ash integration indexes were investigated with RSD, simple correlation and multiple linear regression analyses. The results showed that: 1) For the degree of comprehensive influence on ash integration, the order of cigarette paper parameters was ash crack rate > burn line width > ash color > ash shrink rate > burn line uniformity. 2) According to the significance degrees, the weights of cigarette paper parameters were determined and a comprehensive ash integration evaluation index was proposed. 3) The regression equation between the proposed index and the cigarette paper parameters was established, and the calculated value of the regression equation agreed well with the actual measured value (R² =0.851). 4) For the proposed comprehensive evaluation index, the degree of influence was ash content > grammage > burn additive content > potassium proportion in burn additive > air permeability. The ash integration improved with the increase of ash content and grammage, while it deteriorated with the increase of air permeability, burn additive content and potassium proportion in the burn additive. This comprehensive evaluation provided technical insights to promote ash integration and cohesion of smoldering cigarettes. [ABSTRACT FROM AUTHOR]

The latest research progress in the application of texture analyzer to the determination of tobacco leaf mechanical properties (softness, adhesion, penetration, pull, shear force, texture and brittleness) was reviewed. It pointed out that the texture analyzer to determine the mechanical properties of tobacco leaves was objective and sensitive, which can more comprehensively reflect the stress conditions of tobacco leaves during storage, transportation, and industrial processing, and the test results were closely related to the quality of tobacco leaves. However, the texture analyzer detection technology in the determination of mechanical proper ties of tobacco leaves also had shortcomings such as high requirements for samples consistency, no standardized test parameters, methods and the necessity to improve detection accuracy and other deficiencies. The research should focus on adjusting and optimizing the test parameters of the texture analyzer, establishing normalized and standardized tobacco sample pretreatment methods and testing procedures; and establishing standard testing methods for tobacco stem return rate, tobacco softness, so as to further promote the application of texture analyzer in tobacco research area. [ABSTRACT FROM AUTHOR]