Researchers have always concluded that results that do not support the hypothesis as unimportant, unworthy, or simply not good enough for publication. However, negative findings are essential for the ...progress of science and its self-correcting nature. We also believe in the importance and indispensability of negative results. Therefore, in this review, we discussed the factors contributing to the publication bias of negative results and the problems to assess the factuality and validity of negative results. Moreover, we emphasized the importance of reporting negative results in cardiovascular research, including treatments, and suggest that the negative results could clarify previously controversial topics in the treatment of cardiovascular diseases and prompt the translation of research on precision cardiovascular disease prevention and treatment.
The aim of the study was to estimate the accuracy of standardized uptake values of 18F-fluorodeoxyglucose (18F-FDG) in lung lesions during positron emission tomography combined with computed ...tomography (PET/CT) imaging, based on phantom studies performed for different PET/CT scanners. MATERIALS AND METHODSThe analysis of the PET/CT with 18F-FDG data was performed for 86 patients newly diagnosed with the lung lesions: malignant tumors (n=37), benign tumors and inflammatory diseases (n=49). The criteria for inclusion in the study were developed considering the recommendations of the Fleischner Society (2017). The characteristics of the lesions on CT met the following requirements: a round shape or close to it; total size of 8 to 30 mm; solid or subsolid structure (with the exception of lesion with ground-glass opacity); a solid part size of ≥8 mm. All the patients had no signs of pleurisy, lymphadenopathy, or cancer history. PET/CT imaging with 18F-FDG was performed with three scanners: Discovery 690 (General Electric, USA), Biograph mCT 128 (Siemens, Germany), and Biograph mCT 40 (Siemens); the preparation of patients prior to the scan was standardized. To determine the reference accumulation of a radiopharmaceutical in the pathological lesion, four scans of a specialized NEMA IEC PET Body Phantom Set (USA) were performed for each scanner. For each unit, the recovery coefficients (RCs) of radioactivity, maximum and recovered (corrected) standardized uptake values (SUVs) were determined. Statistical relationship between the size of lesions, SUVmax and SUVcorrect was evaluated. Data processing was performed using MedCalc v. 19.2.0 software. RESULTSDuring the phantom study, the underestimation of the radioactivity was determined in the spheres with the diameters of 10 and 13 mm, overestimation was observed in the sphere with the diameter of 28 mm. Both underestimation and overestimation of radioactivity were determined for the spheres with a diameter of 17 and 22 mm.SUVmax differed from the reference values for 85 patients (98.8%). The underestimation of these values was found for 63 patients (73.2%) due to the partial volume effect. The greatest underestimation was observed for the patients with 8 mm diameter lesions. Depending on the scanner, the underestimation of the SUVmax in these patients reached up to 54-73%. For 9 patients (25%) with malignant tumors of 9-12 mm, the utility of RC made it possible to avoid false negative results. For the lesions with a diameter of 30 mm, an overestimation of SUVmax up to 22% was determined due to the negative influence of the reconstruction algorithms. CONCLUSIONThe use of RC eliminates the influence of the partial volume effect and reconstruction methods on the accuracy of estimating the SUVmax in lung lesions, which ensures reproducibility, increase in the information content of the method, as well as the comparability of the results of PET/CT with 18F-FDG obtained on the different models of PET/CT units with different technological characteristics.
is to evaluate the efficacy of approaches to sampling during periodic quality control of the artificial intelligence (AI) results in biomedical practice.
The approaches to sampling based on point ...statistical estimation, statistical hypothesis testing, employing ready-made statistical tables, as well as options of the approaches presented in GOST R ISO 2859-1-2007 "Statistical methods. Sampling procedures for inspection by attributes" have been analyzed. We have considered variants of sampling of different sizes for general populations from 1000 to 100,000 studies.The analysis of the approaches to sampling was carried out as part of an experiment on the use of innovative technologies in computer vision for the analysis of medical images and their further application in the healthcare system of Moscow (Russia).
Ready-made tables have specific statistical input data, which does not make them a universal option for biomedical research. Point statistical estimation helps to calculate a sample based on given statistical parameters with a certain confidence interval. This approach is promising in the case when only a type I error is important for the researcher, and a type II error is not a priority. Using the approach based on statistical hypothesis testing makes it possible to take account of type I and II errors based on the given statistical parameters. The application of GOST R ISO 2859-1-2007 for sampling allows using ready-made values depending on the given statistical parameters.When evaluating the efficacy of the studied approaches, it was found that for our purposes, the optimal number of studies during AI quality control for the analysis of medical images is 80 items. This meets the requirements of representativeness, balance of the risks to the consumer and the AI service provider, as well as optimization of labor costs of employees involved in the process of quality control of the AI results.
In recent decades, research has grown increasingly in Iran and consequently, the country has risen dramatically in world rankings based on the number of scientific documents. However, there are many ...evidences that show these researches were ineffective. Therefore, their efficacy should be evaluated which is the main purpose of this study. In this regard, using the descriptive-analytical method and valid secondary data and statistics, the most recent situation or the trend of impact pathway components (from investment to development) were compared with other countries. The required data were extracted from valid databases including UNESCO, World Bank, OECD, Thomson Reuters, SCImago, Islamic Parliament Research Center, National Iranian Productivity Organization, Harvard University, Massachusetts Institute of Technology (MIT), and Enerdata. The necessary calculations and rankings were done using Excel 2007. The results showed that, first, compared with other countries, Iran hasn't given high priority to research and isn't in a serious way to address this matter because in 2010 it ranked 66 (among 89 countries) based on share of R&D expenditure in GDP, 54 (among 88 countries) based on R&D expenditure per capita, 57 (among 72 countries) based on R&D expenditure per researcher, 79 (among 89 countries) based on average investment per research, and in 2000 it ranked 19 (among 21 countries) based on share of basic research in total R&D expenditure. Second, apart from the period leading to 2006, despite an impressive growth in research quantity, Iran share of High Technology products in industrial export shows deterioration. Third, during 1980-2014 Iran Economy Complexity Index has always been negative and placed among third weakest countries. Forth, despite a unique growth in science production, Iran couldn't increase its total factor productivity and has fallen dramatically in world rankings based on energy intensity and GDP per unit of energy used. Therefore, according to the results of current and preceding studies, it is clear that even if there is no external deterrent, these researches cannot still play a tangible role in Iran development.
The study aims to assess the role of EU biomedical research infrastructures in the fight against the COVID-19 pandemic and to analyze their response to the challenges associated with the spread of ...the new pathogen. Materials and MethodsWe analyzed the materials of the Seventh Framework Program for Research and Technological Development (FP7, 2007-2013) of the EU and the Eighth Framework Program "Horizon 2020" (FP8, 2014-2020), official reports of the European Strategic Forum on Research Infrastructures, expert reports, as well as documents of the European Commission, the COVID-19 Data Portal, and other relevant sources of information. ResultsThe analysis revealed that the mechanisms created within the united European research community provided for a flexible response to the emerging threat of COVID-19 as soon as January-May 2020. In particular, information channels were established to timely analyze the research results and coordinate the efforts in the fight against COVID-19. The biomedical infrastructures created in the EU and proved successful earlier have now been mobilized to search for ways of preventing and treating COVID-19. These mechanisms facilitated communication and data exchange between various research institutions and thus laid the ground for new achievements in this area. ConclusionThe decisions taken to combat the COVID-19 pandemic have convincingly illustrated that the EU research infrastructures, integrated into a united ecosystem, are highly adaptable and flexible, which allows to realign priorities in a short time and to create instruments that enable scientists to respond to new challenges.
The article Immunologic criteria of prediction of bone delayed union published in Traumatology and Orthopedics of Russia (2009, N 2) by O.V. Berdyugina, K.A. Berdyugin is a duplicate of the article ...Immunological monitoring of slow down ostheogenesis published in Medical Immunology. 2009;(3-4):371-378. That was the reason for retraction.
Revealed April 20, 2022 by the Editorial Board.
•Recent material research about the thermoelectric has been reviewed.•Recent development and application in thermoelectric generator (TEG) has been reviewed.•Recent development and application in ...thermoelectric cooler (TEC) has been reviewed.
Energy crisis and environment deterioration are two major problems for 21st century. Thermoelectric device is a promising solution for those two problems. This review begins with the basic concepts of the thermoelectric and discusses its recent material researches about the figure of merit. It also reports the recent applications of the thermoelectric generator, including the structure optimization which significantly affects the thermoelectric generator, the low temperature recovery, the heat resource and its application area. Then it reports the recent application of the thermoelectric cooler including the thermoelectric model and its application area. It ends with the discussion of the further research direction.
Currently, software products for use in medicine are actively developed. Among them, the dominant share belongs to clinical decision support systems (CDSS), which can be intelligent (based on ...mathematical models obtained by machine learning methods or other artificial intelligence technologies) or non-intelligent. For the state registration of CDSSs as software medical products, clinical trials are required, and the protocol of trial is developed jointly by the developer and an authorized medical organization. One of the mandatory components of the protocol is the calculation of the sample size. This article discusses the calculation of the sample size for the most common case, the binary outcome in diagnostic/screening and predictive systems. For diagnostic/screening models, cases of a non-comparative study, comparative study with testing of the superiority hypothesis, comparative study with testing of a hypothesis of non-inferiority in cross-sectional studies are considered. For predictive models, cases of randomized controlled trials of the complex intervention "prediction + prediction-dependent patient management" with testing of the hypothesis of superiority and non-inferiority are considered. It is emphasized that representativeness of the sample and other design components are no less important in clinical trials than sample size. They are even more important since systematic biases in clinical trials are primary, and even the most sophisticated statistical analysis cannot compensate for design defects. The reduction of clinical trials to external validation of models (i.e. evaluation of accuracy metrics on external data) seems completely unreasonable. It is recommended to perform clinical trials with the design adequate to the tasks, so that further clinical and economic analysis and comprehensive assessment of medical technologies are possible. The sample size calculation methods described in the article can potentially be applied to a wider range of medical devices.
Numerous research studies have evaluated factors influencing the nature and levels of phenolics and polysaccharides in food matrices. However, in grape and wines most of these works have approach ...these classes of compounds individually. In recent years, the number of publications interconnecting classes have increased dramatically. The present review relates the last decade's findings on the relationship between phenolics and polysaccharides from grapes, throughout the entire winemaking process up to evaluating the impact of their relationship on the red wine sensory perception. The combination and interconnection of the most recent research studies, from single interactions in model wines to the investigation of the formation of complex macromolecules, brings the perfect story line to relate the relationship between phenolics and polysaccharides from the vineyard to the glass. Grape pectin is highly reactive toward grape and grape derived phenolics. Differences between grape cultivars or changes during grape ripeness will affect the extractability of these compounds into the wines. Therefore, the nature of the grape components will be crucial to understand the subsequent reactions occurring between phenolics and polysaccharide of the corresponding wines. It has been demonstrated that they can form very complex macromolecules which affect wine color, stability and sensory properties.
PbTiO3 nanowires is produced by stainless steel reaction kettle with Teflon lined. The crystal structure of nanowire was analyzed by electron backscatter diffraction (EBSD). At present, EBSD is ...seldom used to analyze these powder materials with fine crystalline grain and nanosized materials. An attempt is carried out to analyze the powder materials with fine crystalline grain by EBSD. PbTiO3 nanowires is investigated by EBSD, and then analyzed by X-ray diffraction and Scanning Electron Microscopy (SEM). The crystal structure of PbTiO3 is P4mm(99), and the cell parameter is cell = 3,905 × 4,156 A. Experimental results of EBSD are accordant with that of XRD, which illuminates that surface EBSD analysis technique is feasible to determine crystal structure and orientation of powder material with new structure.
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