bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship Between Physical Exercise and Mobile Phone Addiction of College Students from Low Social Classes
Authors: Yuan Yuan , Yang Jian , Wu Ming
Published: September 2022

Mobile phone addiction has become a common phenomenon among college students, which seriously affects their physical and mental
health. In this process, individuals with a strong sense of loneliness tend to seek social support and belonging in the virtual
network, which leads to the occurrence of mobile phone addiction. At the same time, studies have begun to explore ways to reduce
mobile phone addiction by improving physical activity. The purpose of this study was to explore the impact of low-level college
students' physical exercise on mobile phone addiction, and focuses on the mediating mechanism of loneliness. The mobile phone
addiction scale, the physical activity level scale, and the loneliness scale were selected as the subjects. SPSS 23.0 was used
to perform descriptive statistics, correlation analysis, multiple regression analysis, and bootstrap mediation effect test on
the data. There were significant differences in gender dimensions between physical exercise, mobile phone addiction, and
loneliness of low-level college students. Correlation analysis shows that there is a significant negative correlation between
physical exercise and mobile phone addiction (r = -0.14, P < 0.01) and loneliness (r = -0.15, P < 0.01). Loneliness and
mobile phone addiction (r = 0.29, P < 0.01) was significantly positively correlated. The test results of the mediating
effect show that the 95% confidence interval of the indirect effect Bootstrap produced by loneliness does not contain a value
of 0, indicating that loneliness has a significant mediating effect between the level of physical exercise and mobile phone
addiction (standardized effect value = -0.58, Accounted for 29% of the total effect). The level of physical exercise of low-level
college students is significantly negatively related to mobile phone addiction and loneliness, and loneliness is significantly
positively related to mobile phone addiction. There is a mediating effect of loneliness between physical exercise and mobile phone addiction.
Examining Body Shape Characteristics on Chinese Urban College Male Students
Authors: Shan Shun , Wei Ran , Ding Xiaofen
Published: September 2022

According to the Chinese National Adolescent Health report, the status of adolescent physical health has been decreasing for 26 years. The associated factors which caused such decline was studied and pointed out by Gao (2018). As many scholars claimed, “Sunshine sports” should be implemented to promote the adolescent physical health development (Yang, 2011). Previous study indicated that the age of 18 has been a transition point to study on adolescent physical health. However, there has been few studies conducted on the differences of Body Shape Characteristics (BSC) among different regions. Therefore, the purpose of this study is to examine the differences of BSC focusing on 19-22 years old Han Urban Male College Students (HUMCS). Quantitative comparison research design was employed in this study. Human Subject Institute Review Board approval was obtained. Data were collected from five Chinese National Physical Health reports (1995, 2000, 2005, 2010, and 2015). Non-parametric Kernel Density estimation and Kruskal-Wallis test were utilized to examine the characteristics of dynamic trends on HUMCS. Analysis of Variance (ANOVA) was employed to reveal the differences on BSC from different regions. The statistical results revealed that there were significant height and weight increase from 2000-2015. HUMCS from East region were significantly higher and heavier than the West region, while no difference revealed between East and Mid region. Specifically, the height growth curve shifted from 171.5cm to 173.1cm and the weight of HUMCS increased first, followed by slightly decreased. In addition, the chest circumference of HUMCS had been maintained consistently at about 86cm from 1995 to 2015, only slight decreased in 2005. Moreover, there was significant chest circumference difference between East and West region in 1999 and 2005, East and Mid region in 1995, and Mid and West region in 2005. The body shape characteristics of 19-22 years old Han Urban Male College Students from West, Mid and East region have been significantly increased, which indicated that the overall life and diet standard and living environment have been improved. However, strategies for overweight and obesity of adolescent in developed region such as East and Mid region should be taken. Low nutrition status in undeveloped region such as West region may need more attention.
Gender Differences in Value Orientation of PE Teachers in Chinese Secondary Education
Authors: Huang Yuchen
Published: September 2022

This study analyzed the performance of gender differences in value orientation of physical education teachers in junior and senior high schools. Researcher selected 16 middle school PE teachers(8 males and 8 females) in China under the premise of controlling the environment（all objects work in first-tier urbans）, education background (same degree and graduated from same university) and working years(3 years). Participants’ value orientation was assessed with the value orientation scale and individual interviews. The results illustrated that female teachers rated the self-actualization index and social responsibility index the highest, while male counterparts were more likely to orient teaching towards disciplinary mastery and learning process. Interview data further confirmed the assertion. Compared to females, male teachers were more masculine- and authoritative- oriented, more likely to be dominant in terms of skill acquisition and sports development based on students’ interests. However, female teachers were better at carry out teaching through praise, encouragement and patient communication. A systematic analysis of the gender difference in value orientation and underneath reasons leading to the difference is needed to enhance teaching and cultivate talents in physical education.
Relationship Between Procrastination and Exercise Behavior Among College Students
Authors: Zhang Yuan , Yang Jian , Wu Ming , Yuan Yuan
Published: September 2022

Procrastination is prevalent in the study and life of the college student population. There is evidence suggesting that procrastination can have a
negative impact on mood and behavior. However, in the field of exercise, the effects and mechanisms of procrastination on exercise have not been
widely studied. Therefore, this study investigates the relationship between procrastination and exercise volume of college students, and discusses
the mediation effect of time efficiency. The sample comprised 910 university students from 5 provinces（female: 509, male: 401）who completed
inventories assessing their procrastination, time efficiency and exercise volume, and the relationships between these variables were examined
using a model of mediation. In the present study, the appropriate IRB approval has been obtained from East China Normal University. There are
significant differences in procrastination (t = 2.43, p < 0.05) and exercise volume (t = 7.42, p < 0.01) among college students of different
genders and no difference in the sense of time efficiency. The body mass index is classified as lean (BMI < 18.5), normal (18.5 ≤ BMI ≤ 23.9),
overweight (24.0 ≤ BMI ≤ 27.9) and obese (BMI ≥ 28) by standard, and there are significant differences between body mass index and exercise volume
(F = 7.51, p < 0.01). Procrastination was negatively correlated with time efficiency (r = -0.525, p < 0.01) and exercise volume (r = -0.159, p < 0.01),
and there was a significant positive correlation between time efficiency and exercise volume (r = 0.164, p < 0.01). Mediating effect test shows
that the time efficiency has a certain intermediary effect between procrastination and exercise volume (indirect effect = -0.090, LLCI = -0.163,
ULCI = -0.012). Findings provide support that procrastination affects college students' physical exercise through time efficiency. We can start
with improving college students' time efficiency to promote the participation of physical activities. Future research needs more attention to
overweight and obese college students.
The Influence of Intermediate Intensity Intermittent Cycle Training on College Students’ Fitness
Authors: Guo Qinghua , Yang Jun , Gao Tian , Yang Jilong
Published: September 2022

Australia F45 functional training is a high-intensity intermittent cycle training method, integrating life, interest, competitiveness and cooperation together. The purpose of this study was to examine the effect of this training method on college students’ physical quality. 30 Participants from a university in southwest of China were recruited and were divided into two groups. The control group used traditional training methods while the experimental group used indirect circular training method, moderate intensity (pulse control at an average of 140-160 times / min), with the cooperation of music training. The corresponding fitness was tested before and 6 weeks after the experiment. Before and after the experiment, the scores of 50m, standing long jump, pull up / sit up, sitting forward, 800m / 1000m were tested respectively. The content of classroom training was composed of the auxiliary training contents of the five qualities: high leg lifting, small step running, frog jump, upright jump, push-up, flat support, standing forward and so on. The fitness of the students in the control group and the experimental group was improved, and the improvement of the experimental group was more obvious, especially the standing long jump, sit ups and long-distance running. It is suggested that college students accept the medium intensity intermittent cycle training method, which can improve the physical quality of college students.
Influencing Factors and Future Route of Chinese Teenagers’ Health Based on the Healthy China 2030 Strategy
Authors: Zhang Rui , Zou Yunjin , Yao Fanghong
Published: September 2022

The purpose of this study was to examine the influencing factors for Chinese teenager health and possible future route according to the Healthy China 2030 Strategy. Using data from physical fitness test of Han nationality students aged 7-18 years in in 2014, we analyzed the influencing factors and the degree of physical health of Chinese teenagers. Combining dimensionality reduction, visualization and other unsupervised machine learning techniques, 6 physical fitness indicators, including vital capacity, standing long jump, 50-meter run, muscle strength, endurance and grip strength, were converted into 2 two components, accounting for 91% of the total variance. Applying multivariate logistic regression models, we revealed that physical factors were closely related to health, the increase in age and height were accompanied with the improvement in physical health. However, there was a negative correlation between physical education and physical health. Additionally, there was a significant positive correlation between adequate public health input and higher physical health, while the correlation between social economic level and physical health was weak. To improve teenager’s health, the government should actively carry out national policies and cooperate with a top-level design. The society may integrate resources to help teenagers to keep fit while the school implements policies to guarantee the sustainable development of physical health.
Research on the Problems and Optimization Paths of Sports Event Governance in China
Authors: Peng Bo , Yin Zhihua
Published: September 2022

The State Sports General Administration issued "Some opinions on promoting the reform of sports event approval system" on December 30, 2014, clearly canceling the right of approval of mass sports events. Based on this, the community has reflected well, and the quantity and quality of sports events have been significantly improved, but this change has also increased the difficulty of sports event governance. This paper aims to summarize the problems existing in the governance of sports events and the corresponding optimization paths and provides suggestions for the healthy development of sports event. The literature was searched using a keyword “sports event governance” in CNKI. A total of 32 documents were retrieved. Based on the combination of literature content and certain expansion, thirty documents were included in this review. The research progress of sports event governance is expounded from the aspects of concept definition, background of sports event governance, problems existing in sports event governance, and the optimization paths of sports event in China. The problems in the governance of sports event in China include: (a) The power and responsibility of government departments are unclear; (b)The market system is not perfect and the market regulation function is weakened; (c) There lacks materialization of sports social organizations; (d) There are problems in the distribution of benefits among relevant departments, market players, and sports social organizations. The optimization paths of sports event governance include: (a) Clearing government ' s power and responsibility in sports event governance; (b) Improving the market mechanism to enhance the main regulatory capacity; (c) Establishing new supervision mechanism between government and society. The decentralization at the government level has greatly promoted the enthusiasm of social organizations to host sports event, but the new order will always be accompanied by some chaos at the early stage. There are some problems at the government level, the market level, and the social sports organization level. The solutions to these problems are still at the research stage. For example, the optimization schemes of various subjects mentioned in this paper have been gradually studied and summarized.
Analysis on the Choreographic Characteristics of the Top Eight Jazz Cheerleading Events in the 2019 World Cheerleading Championship
Authors: Guo Ge , Zhou Yan
Published: September 2022

As the highest award platform in cheerleading competitions, the World Cheerleading Championship is participated by the elite teams and international judges and experts from all over the world. This paper aims to explore the similarities and differences between excellent teams from the aspects of complete sets of dance movements, difficult movements, complete sets of music, and stage visual effects. To collect data, we searched relevant documents and materials through China Knowledge Net, Wanfang data periodical net, and other information networks. Meanwhile, we watched videos of the top eight teams that participated in the 2019 World Cheerleading Championship. In addition, we conducted face-to-face and telephone interviews with cheerleading field senior experts. Comparative analysis was conducted to analyze the data. The analysis revealed a few patterns. First, almost all teams used a large number of collective movements and rich formation changes to give the audience a visual impact. Second, the choreographers made reasonable arrangements for difficult movements based on the team members’ abilities. Third, most teams chose the classical or current popular songs to arouse the audience. Fourth, choreographers decided on the theme of the music before choreographing dance moves and difficult moves, and how the set would be displayed at the climax of the program. Based on the results, we recommend Jazz cheerleading teams to consider adjusting the frequency of formation changes to stage space. Difficult movements should be chosen based on appropriateness and quality under the rules of collective jazz events. We also recommend using appropriate arrangement styles to showcase the physical qualities of athletes.
Experimental Study on the Influence of KDL Physical and Health Education Curriculum on Primary School Students' Physical Fitness
Authors: Wenrui Fan , Xiaozan Wang , Mingming Guo
Published: September 2022

Physical and Health Education Curriculum (KDL) is a curriculum based on China's Sports and Health Curriculum Standards and China's Health
Sports Curriculum Model. This study aims to explore the influence of KDL on primary school students' physical fitness. A total of 91 primary
school students participated in this study, including 47 in the experimental group and 44 in the control group. The experiment lasted for 18
weeks. During the experiment, the PE teacher of experimental group used KDL to teach, with specific requirements: (1) The activity time of
each class was more than 75%, and the intensity, measured with average heart rates, was above 140-160 beats/min; (2) Each class had about 10
minutes of physical exercise; and (3) each class focused on activities and competitions. The control group was given routine physical education
lessons without intervention. Before and after the experiment, both groups participated in physical fitness tests, including 50-meter running,
vital capacity, seat forward flexion, and 1-minute rope jumping. SPSS was used to analyze the physical fitness of both groups. Before the
experiment, there was no significant difference in physical fitness between the two groups. After the experiment, the experiment group
outperformed the control group in the 1-minute rope skipping (t = 10.77, p < 0.05) and exceled in the vital capacity (t = 0.04, p < 0.05).
There was no significant difference in other physical fitness tests between the two groups. This study shows that KDL curriculum has a significant
positive impact on physical fitness of primary school students, mainly reflected in vital capacity and 1-minute rope skipping. The effect may be
related to the high time on task and appropriate intensity advocated by KDL curriculum. We recommend KDL physical curriculum to be promoted in
primary and secondary schools.
Gender and Grade Differences in Knowledge and Behaviors Related to Active Living for Adolescents
Authors: Wang Baofu , Liu Yang , Imagbe Stacy , Chen Senlin
Published: September 2022

The purpose of this study was to examine differences by gender and grade in middle school students’ physical activity and
fitness (PAF) knowledge, physical activity, and sedentary behavior (SB). The study took place at one middle school located in the
Southeastern region of the United States. Boys (n = 136) and girls (n = 166) in 6th (n = 129),
7th (n = 96) and 8th (n = 77) completed a PE Metrics written test to assess PAF knowledge.
They (N = 312) also completed the validated Youth Activity Profile to report physical activity at school (PAS), physical activity
at home (PAH), and SB. Two-way (gender by grade) multivariate analysis of variances (MANOVA) followed by Bonferroni post-hoc multiple comparison
analysis were conducted. Box’s M test of covariance matrices showed no statistical violation (M = 37.78, F = .73,
p > .05). The two-way MANOVA showed significant gender (Wilks’s λ = .94, F = 4.40, p < .01, 𝜂(2/p)= .06) and grade main
effects (Wilks’s λ = .89, F = 4.20, p < .01, 𝜂(2/p) = .05) Subsequent tests of between subjects effect located the
significant gender difference in PAS favoring boys (F = 9.3, p < .01, 𝜂(2/p) = .03). Boys and girls
showed no significant difference on PAF knowledge, PAH, and SB. Significant grade differences were observed for PAS (F = 8.57, p < .01,
𝜂(2/p) =.06), PAH (F = 8.18, p < .01, 𝜂(2/p) =.05), and
SB (F = 4.61, p = .01, 𝜂(2/p) = .03). Sixth grade students showed significantly higher levels of PAS
and PAH than 7th and 8th grade students (p < .05 or < .01). Sixth grade students further showed significantly
lower SB than 7th grade students (p < .05). This study found boys to be more physically active during school hours
than girls, and students in lower grades to be more active than higher grade students. Future school-based interventions should take into account gender
and grade-based differences.
The Effect of Different Similarity Distance Measures in Detecting Outliers Using Single-Linkage Clustering Algorithm for Univariate Circular Biological Data
Authors: Zulkipli Nur Syahirah , Satari Siti Zanariah , Wan Yusoff Wan Nur Syahidah
Published: September 2022

The procedure of outliers detection in univariate circular data can be developed using clustering algorithm. In clustering, it is necessary to calculate the similarity measure in order to cluster the observations into their own group. The similarity measure in circular data can be determined by calculating circular distance between each point of angular observation. In this paper, clustering-based procedure for outlier detection in univariate circular biological data with different similarity distance measures will be developed and the performance will be investigated. Three different circular similarity distance measures are used for the outliers detection procedure using single-linkage clustering algorithm. However, there are two similarity measures namely Satari distance and Di distance that are found to have similarity in formula for univariate circular data. The aim of this study is to develop and demonstrate the effectiveness of proposed clustering-based procedure with different similarity distance measure in detecting outliers. Therefore, in this study the circular similarity distance of SL-Satari/Di and another similarity measure namely SL-Chang will be compared at certain cutting rule. It is found that clustering-based procedure using single-linkage algorithm with different similarity distances are applicable and promising approach for outlier detection in univariate circular data, particularly for biological data. The result also found that at a certain condition of data, the SL-Satari/Di distance seems to overperform the performance of SL-Chang distance.
Pesquisa em Educação a Distância: Identificação dos Temas Mais Explorados e Negligenciados em Artigos Publicados de 2002 a 2021
Authors: Silva Leandro de Oliveira , Moraes Juliana Lopes , Paes Deise Ferreira Fernandes
Published: September 2022

Com a promulgação da Lei de Diretrizes e Bases da Educação Nacional a educação a distância foi regulamentada. Desde então, a oferta de cursos nesta modalidade cresceu de forma significativa. Esse crescimento se reflete nos artigos publicados ao longo dos últimos vinte anos, os quais discutem os mais diferentes aspectos da educação a distância. Aqui apresentamos os resultados de uma pesquisa quantitativa, que investigou publicações de 13 revistas especializadas em educação a distância e 78 revistas não especializadas, de 2002 a 2021. Nós identificamos 1266 artigos de revistas especializadas e 100 artigos de revistas não especializadas com temas diretamente ligados à educação a distância, classificados em 45 diferentes categorias. Após categorização de todo o espaço amostral, decidimos concentrar a atenção sobre os artigos das revistas especializadas, uma vez que estes periódicos se dedicam a publicar pesquisas específicas da área. Considerando estas revistas, as dez categorias com mais artigos foram: Curso/Programa; Tutor/Tutoria; Material/Design Instrucional; Disciplina; Sujeitos; Tecnologias da Informação e Comunicação; Ferramentas digitais; Revisão; Educação a Distância x Presencial, e Inclusão/Acessibilidade. As dez categorias com menos artigos publicados foram: Feedback; Inovação em Educação a Distância; Concepção de aluno; Políticas Públicas e Educação a Distância; Competências; Estilos de aprendizagem; Metodologias ativas em Educação a Distância; Sala de aula invertida; Motivação, e Silêncio virtual. Esperamos que os resultados obtidos auxiliem pesquisadores em um novo olhar para a educação a distância, sugerindo aspectos que ainda necessitam de maiores investigações e, desta forma, contribuindo para o desenvolvimento de futuras pesquisas.

Palavras-chave: Educação a distância; EaD; Revisão integrativa.
Emerging Issues and Challenges to Fiscal Federalism in Pakistan
Authors: Rasheed Rizwana , Rashid Aamir
Published: September 2022

After the enactment of the 1973 constitution, the defined roles of federal and provincial governments hit snags when democracy got derailed by two martial laws between 1977 and 2008. The consequences were obvious, as the federation; inter-provincial harmony, and intergovernmental fiscal relations witnessed wide socio-economic development gaps in Human Development Index amongst provinces. The genuine pressing public demand was reflected through a consensus of 7th NFC award during the 18th constitutional amendment by then the democratic government to create harmony in society in general, raising the responsibilities, in particular. The analysis examined the issues like enforcement of fiscal discipline, strengthening the role of the Senate of Pakistan, local governments, barriers to internal trade, absence of fiscal responsibility laws, devolution of further taxes such as GST on retail sales and wholesales needs to be corrected to mitigate dividends of 7th NFC award making fiscal federalism principles a great success in Pakistan.
Social-Demographic and Cultural Determinants of Nigerian Women's Age at First Birth Using the Log Logistics Accelerated Failure Time Model
Authors: Esiaba Gladys Ezenwanyi , Chukwu Angela , Ezike Emmanuella Onyinyechi , Obite Chukwudi Paul
Published: September 2022

Early age at first birth has many negative effects on women which includes but are not limited to truncation in education, maternal mortality, sexually transmitted infections, difficulties resulting from pregnancy before a woman is physically mature, cervical cancer, and missing life opportunities in general. In this study, we determined the factors that influence the age at first birth so as to promote child and maternal health in Nigeria. Secondary data from the 2018 Nigeria Demographic and Health Surveys (NDHS) and the Accelerated Failure Time (AFT) model were used in this study to establish the determinants of a woman’s age at first birth in Nigeria. The Log logistics AFT model was used after the dataset failed to satisfy the Cox Proportional Hazard (CPH) model’s assumption. The results show that women from the North Central (NC) will give birth before the women in the North West (NW) and South South (SS). Those with no education will give birth earlier than those with secondary education. Women who do not know their husband’s status will give birth earlier than those that want the same thing as their husband. The women that are more exposed to early first birth as discovered from this study should be empowered and educated so as to discourage early marriage. Policy makers should take decisions to help promote the health of the mother and her child. This will reduce the number of school dropout of women and more opportunities for women over the course of life.
Adoption of Target Costing in Diverse Industries: A Qualitative Study
Authors: Alam Mahjabeen Binte , Ahmed Tanvir , Khan Zahin Irfan , Haque Masnun , Hera Shehrly Mahboob
Published: September 2022

The motive of this paper is to review the articles and research papers regarding the adoption of target costing in different sectors and examines several findings and gaps in the existing literature. This paper reviews existing literature from some renowned journals, official associations and published researches from various timelines. Review of eighteen-journal paper related to target costing is included in this paper. Implication of target costing is the main point of the papers, which is included. Target costing is a popular concept, which is proved to bring better result if applied in the earlier design stages and if firms have a good coordination among their various departments. The papers mostly tested manufacturing firms and construction firms. The findings of the paper suggest that most of the companies do not consider any particular policy for target costing even though these are from same type of industries. Target costing related papers are hard to find in Bangladesh and this paper attempts to give an overall review on the major findings from its adoption. It discovers some gaps in the current existing literature and requires further researches on its application on various other industries.
A Field Study on the Relationship between Personality and Professional Commitment
Authors: Ucar Omur , Ersoy Asli , Aksu Akin , Ehtiyar V Ruya
Published: September 2022

The study aims to reveal the relationship between the personality traits and professional commitment of university students and to determine whether personality affects professional commitment. For this purpose, 272 students studying at Akdeniz University, Faculty of Tourism participated in the research. A questionnaire was used as the data collection tool. Arithmetic mean and standard deviation values were calculated to determine students’ personality traits and organizational commitment levels. Correlation analysis was performed to calculate the relationships between the variables discussed in the study, and multiple linear regression analysis was carried out to identify the predictive power that the independent variables had on the dependent variables. Research results indicated that there was a significant and positive relationship between the students' personality traits and professional commitment levels. In addition, it was determined that the extraversion personality trait was a significant predictor of the affective commitment dimension, neuroticism personality trait was a significant predictor of the continuance commitment dimension, and agreeableness personality trait was a significant predictor of the normative commitment dimension. It is believed that the results of the study will provide concrete information about the relationship between professional commitment, one of the main problem areas of the sector, and personality, one of the key concerns and interesting topics in the field of organizational behavior and bring considerable benefits to the business world.
Investment in Community Development and Return on Assets: Does it Matter?
Authors: C. G Ahannaya , A. T Iwala , J. E Umukoro
Published: September 2022

The debate as to what drives return on asserts has remained unabated. Contextual reports have shown that despite organizations declaring several corporate responsibility initiatives to collaborate with the host communities, financial pointers of Oil firms such as, return on assets have maintained fluctuating performance and a steady decline. Thus, this paper probed into the impact investment in community development has on return on assets. The paper employed an Ex-post facto research design with a focus on the population of five multinational oil firms in Nigeria based on availability of data. The study made use of secondary data sourced from the annual reports of the sampled oil companies for a period of ten years (2006 - 2015). The study adopted inferential statistics for panel data analysis. Results revealed that investment in community development had a positive significant impact on ROA (R2 = 0.44, t-statistic is -3.486992 and p = 0.0011) of multinational oil companies in the Niger Delta Nigeria. The study recommended that management of companies should adopt viable strategies to explore community development for the host communities and improve companies host communities’ liaison to achieve sustainable development and guarantee enabling business operating environment in return.
Evaluation of Prevalence and Quality of Root Resorption of Second Molar Adjacent the Impacted Third Molar in Cone-Beam Computed Tomography
Authors: Arefifard Zeynab , Zare Jahromi Maryam , Ghaffari Roshnak , Mir Sattari Sanaz
Published: September 2022

Introduction:  Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to external root resorption of the adjacent second molar. The aim of this study was to evaluate the prevalence and quality of this resorption using cone-beam computed tomography scanning.
Materials & Methods: In this descriptive study, CBCT images selected from 60 patients (including 107 maxillary & mandibular impacted third molars) were obtained from patients referring to maxillofacial radiology department of dental faculty of Islamic Azad University of Isfahan (Khorasgan) in 2016. Under observation of oral radiologist, the images were examined (two times with one-week interval) in axial, coronal, and sagittal sections and recorded to diagnose external root resorption in CBCT. The data were analyzed via descriptive statistics including contingency tables and relative abundance.
Results: The prevalence of external root resorption of second molar, adjacent to the third molar were 43.25%. The most common type of third molar impaction were mesioangular third molars (41.1%) and in the next level were the vertical (28.1%), and distoangular (18.7) and then horizontal (12.1). The most common location of resorption in mandibular second molar teeth was in 1/3 of cervical (62.5%), and then 1/3 of apical (20.8%) and 1/3 of the middle (12.5%). Also one of teeth resorptions (4.2%) was between the 1/3 of apical and 1/3 of the middle. The most common site of resorption in maxillary second molar teeth was at 1/3 of the apical (68.45%), and then at the 1/3 of the middle (17.35%) and 1/3 of cervical (8.7%). With regards to the severity of resorption; 78.96% of resorptions were mild, 12.03% severe, and 9.03 were moderate.
Conclusion: The prevalence of this type of resorption is almost high and the most common position of impacted third molars that resulted in this type of resorption are mesioangular and horizontal. Most common site of resorption in the maxilla was 1.3 of the apical and in the mandible was 1.3 of the cervical, which were often mild in resorption.
The Effect of Type and Mode of Light Curing Units on Degree of Conversion of Bulk Fill Composites
Authors: Hoseinifar Razieh , Lashkarizadeh Lida
Published: September 2022

Introduction: Adequate polymerization is a critical factor in obtaining optimal physical and mechanical properties and a satisfying clinical outcomes in composite restorations. The aim of this study was to evaluate the effect of type and mode of light curing units on degree of conversion (DC) of Bulk Fill composites (Xtra-fill andTetric N-Ceram Bulk Fill) compared to conventional composite (Tetric N-Ceram).
Materials & Methods: This in-vitro experimental study was conducted in Kerman and Tehran School of Dentistry in 2019. Number of 15 uncured composites and 45 composite discs were fabricated using the Teflon molds with a 4 mm thick and 10 mm diameter and light cured from the top using LED ramp, LED and QTH curing units for 20 seconds. Bulk Fill composites (Xtra-fill andTetric N-Ceram Bulk Fill) were placed with a 4mm_thick increment and conventional composite (Tetric N-Ceram) was placed incrementally (with 2 mm thickness in each layer). The degree of conversion of top and bottom surfaces of composites were measured using the Fourier Transform Infrared Spectroscopy (FTIR). The results were analyzed with Two-way ANOVA and Tukey̛ s test. The level of significance was set as p value < 0.05.
Results: In all samples, the DC value of top surfaces was significantly higher than the 4mm depth (p value < 0.05). Overall, there were no significant difference between the DC value of tested composites (p value > 0.05), But LED light in ramp mode showed significantly better results compared to LED and QTH light sources (p value < 0.05). The type and mode of light cure units had no influence on DC of bulk fill composites (p value > 0.05), but the DC of conventional composite with QTH and LED ramp was significantly higher than LED (p value < 0.05).
Conclusion: The results of this study showed that the DC value of bulk fill composites were not significantly affected by the type and mode of light cure units, and all investigated bulk fill composites obtained clinically acceptable degree of conversion at 4 mm depth.
Dental Students’ Self-Confidence Level in Performing Endodontic Treatment in Dentistry Faculty of Rafsanjan University of Medical
Authors: Yaghooti Khorasani Mohammad Mahdi , Abedi Pouya , Tahernejad Khatereh , Sadeghi Mostafa , Iranmanesh Foad
Published: September 2022

Introduction: The students’ self-confidence level is a key factor affecting the success of endodontics learning. This study aimed to determine the confidence level of dental students who performing root canal treatment at Rafsanjan University of Medical Sciences in 2021.
Materials & Methods: In this cross-sectional study a questionnaire including demographic information, endodontic experience, attitude toward confidence in performing different stages of root canal treatment, and suggestions for improving the quality of endodontic education was distributed among 54 dentistry students from 5th and 6th -year during the last month of the academic semester. Data were analyzed using T-test, Pearson, and ANOVA tests (α = 0.05). 
Results: According to the results, of 49 dental students, 24.5% reported the first cases of root canal treatment to be tough. The lowest confidence was reported for finding all root canals in teeth with multiple root canals, preparing access cavity and understanding and managing root canal treatment risks. According to the results of chi-square analysis test, the total confidence score between 5th and 6th year students was not significantly different (p value = 0.648). Also, the relationship between general selfconfidence and students' self-confidence level was not seen (p value = 0.372). There was no significant relationship between the Confidence level and age, academic year, the difficulty level of the first endodontic treatment, and number of endodontic treatments (p value > 0.05).
Conclusion: Students had lower self-confidence finding all the canals in multi-canal teeth, in properly handling the treatment risks, and preparing the access cavity. Endodontics training should also be improved by increasing clinical sessions and using recent advances in endodontics.
Assessment of Knowledge of Senior Dental Students of Isfahan University of Medical Sciences on Medical Emergencies
Authors: Faghihian Elham , Saied-Moallemi Zahra , Zare Nafiseh
Published: September 2022

Introduction: Medical emergencies during dental treatment are likely to occur. The ability of a dentist to manage medical emergencies requires sufficient knowledge and information. The purpose of this study was to survey the level of knowledge of the undergraduate dental students of Isfahan University of Medical Sciences on medical emergencies.
Materials & Methods: In the cross-sectional study in 2019, 60 senior dental students at the University of Medical Sciences of Isfahan were evaluated. A questionnaire was used for data collection with confirmed validity and reliability. Data was analyzed with correlation coefficients and independent t-test with level of significance at 0.05.
Results: Participants' overall knowledge scores were 7.53 ± 2.58 out of 12. There wasn’t a significant difference between the knowledge of male and female students (p value = 0.72). Also this study revealed a relative relationship between students' medical emergencies score and their knowledge on emergencies (p value < 0.001, r = 0.48).
Conclusion: The knowledge status of senior dental students on medical emergencies was not desirable. It is recommended that more educational content like theoretical classes and practical workshops should be considered for dental students.
Evaluating Patients' Satisfaction in Isfahan Dental School during COVID-19 (Academic Year 2020-2021)
Authors: Razavi Seyed Mohammad , Vakili Fatemeh
Published: September 2022

Introduction: The aim of this study was to evaluate the satisfaction of patients in the School of Dentistry of Isfahan University of Medical Sciences during the COVID-19 pandemic (Academic Year 2020-2021).
Materials & Methods: This is a cross-sectional descriptive-analytical study utilizing a self-made questionnaire with confirmed validity and reliability, comprising 34 questions including demographic details, inter-personal parameters, ease and access to infection control to assess patients'satisfaction in the Dental faculty during the COVID-19 pandemic from 251 patients in the academic year 2020-2021. Finally, the data were analyzed using descriptive statistical methods including mean and standard deviation, frequency distribution tables, and statistical methods including independent t-test, Pearson correlation coefficient and one-way analysis of variance. (p value > 0.005).
Results: In the present evaluation, it was observed that most of the patients of the study were from the general endo ward (20 patients - 8%). The highest overall satisfaction of patients was reported at the specialized surgery ward with a mean of 144.25 ± 24.92, the lowest at the specialized prosthesis ward with a mean of 128.41 ± 8.30 and the overall satisfaction of patients had a mean score 136.60 ± 19.32 out of 170 (80.35%).
Conclusion: In general, the level of satisfaction of patients referred to Isfahan Dental School during the corona pandemic was relatively good.
Myo-inositol effect on pregnancy outcomes in infertile women undergoing in vitro fertilization/intracytoplasmic sperm injection: A double-blind RCT
Authors: Seyedoshohadaei Fariba , Abbasi Shahin , Rezaie Masoumeh , Allahvaisi Azra , Rezaie Mohammad Jafar , Soufizadeh Nasrin , Rahmani Khaled
Published: September 2022

Background: Myo-inositol is an intracellular mediator which is involved in various aspects of reproduction in women.
Objective: This study aimed to evaluate the impact of Myo-inositol on the outcomes of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles in infertile women.
Materials and Methods: This double-blind randomized controlled trial was conducted on 70 infertile women referred to the Infertility Treatment Center, Besat hospital, Sanandaj, Iran from May 2019 to September 2019 for IVF/ICSI cycles. The participants were randomly divided into 2 intervention (n = 36) and control (n = 34) groups. The intervention group received 2000 mg of Myo-inositol and 200 mcg folic acid twice a day for 2 months and the control group received 200 mcg of folic acid twice a day for 2 months in the IVF/ICSI cycles (from the third day of cycle until the end of the second month). Finally, the number of oocytes, the quality of embryos, and the IVF/ICSI outcomes were compared between the 2 groups.
Results: The mean numbers of oocytes, MII oocytes, and 2 pronuclear embryos were significantly higher in the intervention group than the control group. Also, the clinical pregnancy and live birth rates in the intervention group were significantly higher than in the controls (p = 0.04).
Conclusion: The administration of Myo-inositol may increase clinical pregnancy and live birth rates by increasing the number of total and meiosis II oocytes in infertile women undergoing IVF/ICSI.
Key words: Infertility, In vitro fertilization, Intracytoplasmic sperm injection, Myoinositol.
Role of CYP1A1, CYP2D6, and NOS3 gene polymorphisms in idiopathic recurrent pregnancy loss in the Iranian Azeri population: A case-control study
Authors: Yousefian Mahsa , Angaji Abdolhamid , Siasi Elham , Rahmani Seyed Ali , Abbasalizadeh Khiaban Shamsi
Published: September 2022

Background: It is estimated that 1-5% of couples suffer from recurrent pregnancy loss (RPL). Recent studies have shown the effects of gene polymorphisms in RPL.
Objective: The aim of this study was to evaluate 3 gene polymorphisms including rs1048943 of CYP1A1, rs28371725 of CYP2D6, and rs7830 of NOS3 in idiopathic RPL to identify their association with RPL.
Materials and Methods: Blood samples were collected from 136 women with at least 2 consecutive idiopathic miscarriages (case group) and 136 women with no history of miscarriage and at least one successful pregnancy (control group) from the Iranian Azeri population. This study was carried out between April 2018-April 2020. Amplification-refractory mutation system polymerase chain reaction was used for the rs7830, rs1048943 and rs28371725 polymorphisms in order to genotype each extracted genomic DNA sample. After that, Chi-square, Fisher’s exact test and logistic regression were used to investigate whether each of these polymorphisms is associated with RPL.
Results: Among these polymorphisms, only rs1048943 of CYP1A1 showed a statistically significant association with RPL in the Iranian Azeri women studied.
Conclusion: Our results suggest that CYP1A1 gene polymorphisms might be associated with a reduced risk of RPL. Further studies in other populations and in the same population with a larger sample size, as well as functional genomics analyses such as gene expression analyses or epigenetic studies are required to validate our results.
Key words: Recurrent pregnancy loss, Polymorphism, CYP1A1, CYP2D6, NOS3.
The selection of the propulsion system of an advanced small space tug
Authors: Shcheglov G.A. , Shapovalov A.V.
Published: September 2022

The paper considers the selection of a main propulsion system of a small space tug, whose development is relevant due to the problem of disproportion between the existing launch vehicles and promising payloads. This problem arose in connection with the active development of multi-satellite constellations. The tendency to increase the number of operated spacecraft turned out to be dialectically related to the tendency to reduce the size of a single spacecraft. The paper introduces the results of the analysis of the functional efficiency of the transport operation and the cost analysis of the options for a small space tug. The analysis was carried out as part of the competition for the development of ultralight launch vehicles, organized by ANO Aeronet. A criterion for selecting a propulsion system for a small space tug from the point of view of efficiency is proposed. The study shows that for a small space tug weighing no more than 80 kg, designed to perform a coplanar transport operation lasting no more than three days with a payload weighing no more than 150 kg and an available reserve of delta-V budget of no more than 500 m/s, the best option is a propulsion system on gaseous oxygen — methane components, which does not require a specialized displacement system and the gas jet engines of the control system work on any of the components.
Application of high power level power and propulsion systems for space transportation
Authors: Koshlakov V.V. , Arkhangelsky N.I. , Zakharenkov L.E. , Karevskiy A.V. , Kuvshinova E.Yu. , Muzychenko E.I. , Semenkin A.V. , Solodukhin A.E.
Published: September 2022

The purpose of the research was to consider the application of high power level power and propulsion systems for different space missions. The paper gives the main components of high power level nuclear power and propulsion systems as well as their architecture options and integration solutions. Within the research, we set requirements to characteristics of high power level power and propulsion systems of advanced spacecraft aimed for different transport missions in near-Earth and deep space, analyzed efficiency of nuclear power and propulsion systems applied for transport missions in comparison with conventional chemical propulsion systems. Findings of the research show that high power level power and propulsion systems have the following advantages in comparison with conventional chemical propulsion systems: increase of payload mass; possibility of direct flights (without gravitational maneuvers) to deep space objects; ensuring power supply of target equipment and communication systems at a qualitatively higher level.