47 research outputs found

    An in vitro study of mesiobuccal root thickness of maxillary first molars

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    Introduction: Understanding the internal anatomy of root canal system can significantly influence outcomes of root canal treatment. The aim of this in vitro study was to measure the thickness of mesiobuccal root at different levels in maxillary first molars. Materials and Methods: In this cross-sectional study, forty extracted human maxillary first molars were radiographed; accordingly, the mesial and distal root thicknesses of mesiobuccal (MB) roots were measured at four parallel horizontal levels. The samples were sectioned at the measured levels and then sections were scanned and saved in the computer. Buccal (B), Palatal (P), Mesial (M) and Distal (D) aspects of root thicknesses in single-canalled roots were measured. In two–canalled mesiobuccal roots, Distobuccal (DB) and Distopalatal (DP) aspects were evaluated alongside other measurements. Average radicular thickness in each aspect and each level was compared using ANOVA and t-test. Results: A total of 25 had two canals and 15 had one canal in MB root. In single-canalled roots M and D aspects were the thinnest whereas in two-canalled samples, the thicknesses of DP and DB aspects were significantly less than others (P<0.001). The B and P had the greatest thicknesses in all the samples. Conclusion: The results showed that special attention should be paid to "danger zone” areas of mesiobuccal maxillary first molar roots in order to avoid technical mishaps

    Estimation of Missing Data in Intelligent Transportation System

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    Missing data is a challenge in many applications, including intelligent transportation systems (ITS). In this paper, we study traffic speed and travel time estimations in ITS, where portions of the collected data are missing due to sensor instability and communication errors at collection points. These practical issues can be remediated by missing data analysis, which are mainly categorized as either statistical or machine learning(ML)-based approaches. Statistical methods require the prior probability distribution of the data which is unknown in our application. Therefore, we focus on an ML-based approach, Multi-Directional Recurrent Neural Network (M-RNN). M-RNN utilizes both temporal and spatial characteristics of the data. We evaluate the effectiveness of this approach on a TomTom dataset containing spatio-temporal measurements of average vehicle speed and travel time in the Greater Toronto Area (GTA). We evaluate the method under various conditions, where the results demonstrate that M-RNN outperforms existing solutions,e.g., spline interpolation and matrix completion, by up to 58% decreases in Root Mean Square Error (RMSE).Comment: presented at the 2020 92nd IEEE conference on vehicular technology, 18 Nov.-16 Dec 2020 6 pages, 5 figures, 2 table

    E-business through Social Media: A Quantitative Survey (Case Study: Instagram)

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    E-marketing is not only associated with selling products and services. It is the management process for handling communication between the organization and the customer. As well as E-marketing process does not just insist on the use of the internet and take advantage of all the marketing methods. E-marketing has many facilities that traditional marketing does not have such as one to one marketing or direct contact with customers. It should be noted that E-marketing can not completely replace traditional marketing. In fact, traditional marketing and e-marketing complement each other. Social network marketing is a part of E-business. It is clear that social media is a place gathering customers and business owners tend to be in this market. Social media are a huge potential for companies to reach out to their customers and thereby increase revenue, reduce costs, and increase productivity. As expected, our findings suggest that social media innovators among companies to rapidly progress. This study focuses more on statistical results rather than theoretical subjects. In fact, due to the lack of proper knowledge about the social media and growing trend for social media, in this research, we decided to survey behavior of  Instagram users towards brands who are active in the social media  or how marketing on Instagram work in order to reach customer? For this purpose, an online questionnaire distributed randomly between 80 users of Instagram application. Results were evaluated in two parts, descriptive statistics and inferential statistics inference. The results of inferential statistics indicate that people are looking for brand awareness and are curious about the messages of the brand. The study showed that there is a significant relationship between commenting on posts and brand awareness

    Under- and overreporting of energy in a group of candidates for CABG surgery and its association with some anthropometric and sociodemographic factors, Tehran, Iran

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    Bahareh Amirkalali1, Mehdi Najafi2, Asal Ataie-Jafari1, Saeed Hosseini1, Ramin Heshmat11Nutrition Department, The Endocrinology and Metabolism Research Centre (EMRC) of Tehran University of Medical Sciences (TUMS), Tehran, Iran; 2Tehran Heart Center, Tehran, IranIntroduction: Numerous studies have documented a high prevalence of misreporting energy intakes. This paper examines the prevalence of under- and overreporting of energy intake in a group of candidates for coronary artery bypass graft (CABG) surgery and its association with body mass index (BMI) and some sociodemographic factors.Subjects and methods: Dietary assessment (using a food frequency questionnaire) and demographic evaluation of 449 CABG surgery candidates was performed. Weight and height was also measured. McCrory equation was used to identify inaccurate records of energy intake. With this equation, reporting energy intake less than 78% and more than 122% of predicted energy expenditure was considered as under- and overreporting, respectively.Results: Less than half of the participants reported energy intakes within the plausible limits. There were more overreporters than underreporters in this sample. The only significant association between misreporting and related factors was seen in BMI groups. As BMI increased, the number of underreporters increased significantly. Expressed as a percentage of total energy, mean carbohydrate intake was significantly lower and mean fat and protein intake was significantly higher in underreporters compared to overreporters.Conclusion: The high prevalence of misreporting suggests more research to examine the characteristics of misreporters. Calibrating data with these characteristics can help to improve intake estimates.Keywords: underreporting, overreporting, energy intake, CABG candidate

    Evaluation of In-vitro Antimicrobial Activity of some Newly Synthe-sized2-amino-3-phenylsulfonyl-4-aryl-4H-benzo[h]chromens Derivatives

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    In this study, some chromens derivatives were synthesized as mentioned in our previous report.The synthesized compounds were evaluated for their antibacterial effect against three different bacterial species, using Disk Diffusion Agar test and microdilution broth (MIC) method against the S. aureus, E. coli, P. aeruginosabacterias according to the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. The results indicated that 4-nitro compound has considerable antibacterial activity against S. aureusbacteria. Moreover, compound 3-chloro has antibacterial properties  againstE. coli standard strain and none of 4H-Chromens derivatives have antibacterial effect on P. aeruginosa  strains

    Intensive care unit-acquired urinary tract infections in patients admitted with sepsis: etiology, risk factors, and patterns of antimicrobial resistance

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    SummaryObjectivesThe objective of the present study was to evaluate the etiology, risk factors, and patterns of antimicrobial resistance of intensive care unit (ICU)-acquired urinary tract infections (UTIs) in patients admitted with sepsis.MethodsIn this observational study, 100 septic patients hospitalized in a general ICU were selected. Demographic, clinical, and outcome data were obtained by chart review. Antibiotic resistance/susceptibility was determined using the minimal inhibitory concentration (MIC) technique.ResultsA UTI was present in 28 (28%) patients; the male to female ratio was 19:9 and the mean age of the patients was 58.71±19.45 years. From the total of 28 isolates, 27 were resistant to ciprofloxacin, 23 to amikacin, 27 to meropenem, 28 to cefepime, 26 to ceftazidime, and 27 to ceftriaxone.ConclusionsOn the basis of our results, the rate of multidrug-resistant UTIs may be very high in some ICUs in patients admitted with sepsis. This antimicrobial susceptibility/resistance should be determined, and a special antimicrobial treatment protocol should be planned based on the results for each ICU. The use of antibiotics for treating UTIs should be guided only through this protocol because of the different spectra of pathogens and susceptibility patterns in each ICU

    An assessment of health research impact in Iran

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    Background: In recent years, Iran has made significant developments in the field of health sciences. However, the question is whether this considerable increase has affected public health. The research budget has always been negligible and unsustainable in developing countries. Hence, using the Payback Framework, we conducted this study to evaluate the impact of health research in Iran. Methods: By using a cross-sectional method and two-stage stratified cluster sampling, the projects were randomly selected from six medical universities. A questionnaire was designed according to the Payback Framework and completed by the principle investigators of the randomly selected projects. Results: The response rate was 70.4%. Ten point twenty-four percent (10.24%) of the studies had been ordered by a knowledge user organization. The average number of articles published in journals per project was 0.96, and half of the studies had no articles published in Scopus. The results of 12% of the studies had been used in systematic review articles and the same proportion had been utilized in clinical or public health guidelines. The results of 5.3% of the studies had been implemented in the Health Ministry’s policymaking. 62% of the studies were expected to affect health directly, 38% of them had been implemented, and among the latter 60% had achieved the expected results. Concerning the economic impacts, the most common expected impact was the reduction of ‘days of work missed because of illness or disability’ and impact on personal and health system costs. About 36% of these studies had been implemented, and 61% had achieved the expected impact. Conclusion: In most aspects, the status of research impact needs improvement. A comparison of Iran’s ranking of knowledge creation and knowledge impact in the Global Innovation Index confirms these findings. The most important problems identified were, not conducting research based on national needs, and the lack of implementation of research results. Keywords: Research impact assessment, Payback, Health research syste

    Establishing research impact assessment in Iran: The first report from a non-high-income country

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    Background This study presents the first report on research impact assessment (RIA) in non-high-income countries, undertaken as a pilot initiative in 2021. Within it, we aimed to explore the feasibility of employing the ‘payback’ model for evaluating the impact of health research and enhancing the accountability of universities. We focussed on three key impact domains: ‘production of decision support documents and knowledge-based products,’ ‘implementation of research results,’ and ‘health and economic impact.’ Methods We adopted a case study approach to assess the impact of 5334 health research projects conducted by researchers from 18 universities from 2018 to 2020. Researchers were required to submit evidence related to at least one of the specified impact domains; six scientific committees verified and scored claimed impacts at the national level. Results Only 25% of the assessed projects achieved impact in at least one domain, with the production of decision support documents and knowledge products being the most reported impact. Notably, economic impact was verified in only three projects, indicating room for improvement in this area. Technology research exhibited the highest acceptance rate of claimed impact, suggesting a positive correlation between technology-focused projects and impactful outcomes. Conclusions This study demonstrates the feasibility of employing a case study approach and the ‘payback’ model to evaluate the impact of health research, even within the constraints of a moderately equipped research infrastructure. These findings underscore the potential of integrating RIA into the governance of health research in Iran and other non-high-income countries, as well as the importance of using RIA to assess the accountability of health research systems, guide the allocation of research funding, and advocate for the advancement of health research. The study sets a precedent for future assessments in similar contexts and contributes to the ongoing global dialogue on the societal impact of health research

    Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

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    Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening, had elevated FPG, HbA1c or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardized proportion of diabetes that was previously undiagnosed and detected in survey screening ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the age-standardized proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c was more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global shortfall in diabetes diagnosis and surveillance

    Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

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    Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks
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