Human activity factors have a significant impact on changes in ammonia nitrogen (NH3-N) content in rivers. Existing research mainly focuses on human activity factors as type factors, and lacks research on the key factors affecting river NH3-N among human activity factors. Therefore, this paper aims to study the key factors affecting human activities on NH3-N in the Huaihe River through various statistical analysis methods. The study found that changes in NH3-N content in the Huaihe River are mainly affected by land use patterns in the basin. There are two different ways in which land use affects NH3-N in rivers: direct effects and indirect effects. We also studied the main pathways through which changes in key factors in human activities affect NH3-N in the Huaihe River by constructing a structural equation model. The results showed that crop sowing area and afforestation area have a significant direct effect on NH3-N in the Huaihe River. In addition, crop sowing area and afforestation area can also affect river NH3-N by regulating the amount of nitrogen fertilizer and human excrement. This study is of great significance for understanding how human activities regulate NH3-N content in rivers.

Understanding the influence of soil microstructure on light non-aqueous phase liquids (LNAPLs) behavior is critical for predicting the formation of residual LNAPLs under spill condition. However, the roles of soil particle and pore on LNAPLs migration and residue remains unclear. Here, the experiment simulated an LNAPLs (diesel) spill that was performed in fourteen types of soils, and the key factors affecting diesel behavior are revealed. There were significant differences between fourteen types of soils, with regard to the soil particle, soil pore, and diesel migration and residue. After 72 h of leakage, the migration distance of diesel ranged from 3.42 cm to 8.82 cm in the soils. Except for sandy soil, diesel was mainly distributed in the 0−3 cm soil layer, and the residual amounts were 7.85−26.66 g/kg. It was further confirmed from microstructure that the consistency of soil particle and volume of soil macropores (0.05−7.5 μm) are important for diesel residue in the 0−1 cm soil layer and migration distance. The large soil particles corresponding to 90% of volume fraction and volume of soil mesopores (<0.05 μm) are key factors affecting diesel residue in the 1−3 cm soil layer. The result helps to further comprehend the formation mechanism of residual LNAPLs in the soil.

Food safety risk management is an important cross-boundary issue from both theoretical and practical standpoints. Because food safety has the social attributes of public goods, public-public collaboration can be considered a particularly important mode of cross-boundary governance. The study aims to provide a theoretical basis for the Chinese government to promote public-public collaboration for food safety risk management by identifying key factors.
Based on a review of literature across diverse fields, such as political science, sociology, and new public governance, this study discusses the essence, modes, and dilemma of public-public collaboration for food safety risk management using practical explorations in various countries as the main thread and taking into account the actual situation in China. Moreover, this study quantitatively analyzes the relationships between the dimensions and factors affecting public-public collaboration and identifies key dimensions and factors using the Decision-making Trial and Evaluation Laboratory-based Analytic Network Process (DANP).
Among the 20 factors in the calculation results of DANP, Lawmaking has the highest value of (f i +e i ) (7.022) and ranks sixth in terms of influence weight. The (f i +e i )value of Professionalism (6.993) ranks second and its influence weight ranks fourth. The (f i +e i ) value of Administrative enforcement (6.722) ranks fifth, and its influence weight ranks seventh. The (f i +e i ) value of Improvement of the social environment (6.699) ranks sixth, and its influence weight ranks fifth. The (f i +e i ) value of Legal authorization (6.614) ranks seventh, and its influence weight ranks tenth. Data analysis indicated that these are the five key factors affecting the governance capacity in public-public collaboration for food safety risk management.
The legal basis is the most important dimension affecting public-public collaboration. Legislation-based governance, administrative law enforcement-based governance, and social environment improvement-based governance in the behavior and capabilities dimension, professionalism in the basic characteristics dimension, and laws and regulations in the legal basis dimension are the five key factors.

Under the background of globalization and the popularity of distance learning ande-learning channels provided on the Internet, teaching methods that encourage the self-directed learning of students are becoming popular. There is an increasing number of domestic teachers joining in the practice for change. The various teaching methods that make the students acquire critical thinking skills can be summarized as learning by doing, critical thinking learning, multiple assessments, team discussion teaching, and cooperative learning. With the teachers of the universities in Shanghai as the questionnaire analysis objects, a total of 360 copies of questionnaires were distributed, and 256 valid copies were retrieved, with the retrieval rate of 71%. The research results are summarized as follows. (1) The \"mental adaptation and engagement of students\" is the most emphasized dimension, followed by the \"professional development of teachers,\" \"administration and parent support,\" and \"material and teaching strategy.\" (2) The top five emphasized indicators, among 14, are the ordered cultivation of self-study and thinking habits, the development of the professional community for the collaborative lesson study of teachers, the support and cooperation of the president and the administration, adoption of heterogeneous grouping, and co-learning, discussion and cooperative learning. According to the results, it is expected to propose more definite practice directions for teachers intending to attempt such a teaching method, as well as provide some specific suggestions for the first movers of Sharestart.

In this study, the pure terephthalic acid sludge was treated by a drying process which was an economical and environmentally method. The water change and metabolic pathways for bacterial community function prediction were analyzed. The microbial community changes were studied by high-throughput sequencing to draw the dynamic succession model. Then multiple statistics was used to determine the key factors of the reduction. The results showed that the main stage of water loss in the PTA sludge drying process was the high temperature period where the water lost by evaporation accounted for more than 90% of the total removal. The main metabolic pathways for bacterial community function were amino acid (7.72%-8.71% of Kyoto encyclopedia of genes and genomes relative abundance and 8.26%-9.51% of Cluster of orthologous groups of proteins relative abundance) and carbohydrate metabolism. The model describing the dynamic succession of microbial communities showed that the dominant bacteria changed from Nitrospira, Novosphingobium and Azohydromonas to Pseudomonas, Paeniglutamicibac and Pelotomaculum. The key factors for water loss were Gemmatimonas, Novosphingobium and Azohydromonas with the correlation coefficients of 0.887, 0.772, 0.783, respectively; the key factors for dry matter loss were Pelotomaculum, total organic matter, dissovlved organic carbon and carbon/nitrogen ratio; the key factors for toxic substance loss were Brevundimonas, Novosphingobium and Gemmatimonas. These results provided theoretical support for the application and demonstration for hazardous waste sludge reduction.

BACKGROUND: Along with the evolutions of medical sciences education, the importance of medical education discipline has gained more attention for keeping up with these evolutions. Therefore, paying attention to policymaking regarding the development of this discipline and its position in universities is very necessary.
OBJECTIVE: This study has been done with the aim of investigating key educational and research factors affecting the future of medical education discipline in Iran.
METHODS: This is a qualitative study with directed content analysis approach, which has been conducted in eight medical sciences universities having medical education department (Tehran, Iran, Shahid Beheshti, Isfahan, Mashhad, Shiraz, Tabriz, and Kerman) in 2018-2019.
METHODS: A total of 25 participants (professors, students, and graduates) of medical education discipline were selected by purposeful sampling and with maximum diversity. Data were collected through semi-structured interviews. Interviews were analyzed using MAXQDA software.
RESULTS: After analyzing the data, a number of 1561 initial codes were obtained, of which 914 codes were extracted after removing repetitious codes and merging similar codes. Finally, the obtained results from content analysis were classified into two main categories including key educational and research factors and ten subcategories.
CONCLUSIONS: Among the most important key educational and research factors affecting the future of medical education discipline, it can be mention to the role of the discipline curriculum and need to revise it, the need to monitor the graduates and their status , globalization, the role of medical education centers and departments, and the role of theses. It is recommended that future studies investigate other key factors affecting the future of the discipline.

A retrospective analysis of the results of surgical treatment of 436 patients (332 adults and 104 children under the age of 15 years) with acquired middle ear cholesteatoma was performed to identify possible predictors of relapse of the process and a prospective assessment of the results of surgical treatment. It was revealed that the leading factors in the development of residual pathology were: the presence of cholesteatoma in the area of destruction of the bone wall of the canal of the facial nerve, cholesteatoma of the hypothympanum, cholesteatoma in the place of destruction of the bone wall of the posterior cranial fossa. The key reasons for the formation of recurrent pathology were: children under 15 years of age, closed surgery, pathological changes in the tympanic orifice of the auditory tube and the presence of cholesteatoma in its lumen. Performing a closed operation in adults with pathology of the tympanic orifice of the auditory tube increases the risk of recurrent cholesteatoma by 18.6%, and in children by 20%. The choice of a closed method of surgical intervention for the epitympanic type of the disease can increase the risk of residual pathology by 17.2% in adults and 27.8% in children.
Проведен ретроспективный анализ итогов хирургического лечения 436 пациентов (332 взрослых и 104 детей в возрасте до 15 лет) с приобретенной холестеатомой среднего уха для определения возможных предикторов рецидива процесса и проспективной оценки результатов оперативного вмешательства. Выявлено, что ведущими факторами развития резидуальной патологии явились: наличие холестеатомы в области деструкции костной стенки канала лицевого нерва, холестеатома гипотимпанума, холестеатома в месте деструкции костной стенки задней черепной ямки. Ключевыми причинами формирования рекуррентной патологии явились: детский возраст до 15 лет, закрытый тип операции, патологические изменения тимпанального устья слуховой трубы и присутствие холестеатомы в ее просвете. Выполнение закрытой операции у взрослых с патологией тимпанального устья слуховой трубы повышает риск развития рекуррентной холестеатомы на 18,6%, а у детей — на 20%. Выбор закрытого способа оперативного вмешательства при эпитимпанальном типе заболевания может повысить риск развития резидуальной патологии на 17,2% у взрослых и на 27,8% у детей.

The Mg/Al hydrotalcite (Mg/Al HT) was firstly used as a heterogeneous ozonation catalyst and 2,4-dichlorophenoxyacetic acid (2,4-D) was efficiently degraded by Mg3/Al HT with a COD removal of 68 %. It was higher than that of α-FeOOH with a COD removal of 50 %. The effects of Mg/Al atomic ratio, phosphate and pyrrole on the ozonation performance of Mg/Al HTs were also investigated. The X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption experiment and temperature programmed desorption of adsorbed CO2 or NH3 were used to characterize the surface properties of Mg/Al HT. The surface acidity and basity was proven to be responsible to the excellent ozonation activity of Mg/Al HT. The results of electron spin resonance (ESR) analysis and probe experiments confirmed that OH, O2- and 1O2 were involved in the 2,4-D degradation process and their contributions are as followed: OH > O2- > 1O2. The synergistic effect of surface acid (ozone adsorption center) and base sites (catalytic center) determines Mg/Al HT in the enhanced catalytic ozone decomposition into reactive species. More important, the transition metal free based Mg/Al HTs is steady, non-toxic, naturally abundant and environment friendly, which provided a promising alternative in practical water treatment by catalytic ozonation.

OBJECTIVE: Increasing developments in medical education have highlighted the role of medical education discipline in keeping with these developments. On the other hand, this discipline has been encountered with trends, events and challenges at national and international levels; so, there are concerns about its future. This study aimed to identify key factors affecting the future of the discipline from the viewpoint of stakeholders.
METHODS: This study used a qualitative approach based on constructivist paradigm and was conducted in 2019-2018. Thirty-one participants (teachers, students and graduates) of medical education discipline from 8 universities of medical sciences in Iran were selected through purposive sampling with maximum diversity. Data were collected through semi-structured interviews and analyzed using directed content analysis.
RESULTS: The key factors were classified into five main categories: social (characteristics of entrants into the discipline, motivations of candidates for entry into the discipline, national and international communications and interactions, the status of medical education within the academic community, and movement toward social accountability), technological (development of information and communication technology, and role of virtual courses), economic (economic situation of the country, and movement toward third and fourth generation universities), political (role of policies, laws, regulations, rules and policymakers), and values (views of the community on the role of education, and views of the educational system on medical education discipline).
CONCLUSIONS: The most important key factors were student admission and recruitment policies, lack of accurate information on the follow up of graduates, the role of virtual courses and its opportunities and threats, lack of curriculum review and the need to move towards social accountability. This study was a preliminary step towards the foresight of the discipline; so, it is recommended that future studies develop scenarios (possible, feasible and desirable) for the future of the discipline.

As one group of emerging pollutants, the threat of organophosphate esters (flame retardants and plasticizers, OPEs) to drinking water safety is not well recognized. Now, the oral reference dose (RfD) and oral cancer slope factor (SFO) of OPEs have been updated by USPEA, therefore the threat of OPEs to drinking water safety could be assessed. In this study, occurrence, health risk and key impact factor of OPEs in drinking water of China were analyzed covering 79 cities, whose population and gross domestic product (GDP) accounted for 28.8% and 44.1% of them in China, respectively. Total concentration of 14 common OPEs in drinking water was 13.42-265.48 ng/L. The exposure level of OPEs via ingestion of drinking water was much lower than that of food ingestion but was comparable with dust ingestion, inhalation and dermal absorption. A health assessment for OPEs via ingestion of drinking water suggested that the potential cancer risk occurred (>1.00E-6) but no obvious non-carcinogenic effects occurred (<1). Tris-(2,3-dibromopropyl) phosphate (TDBPP) contributed to about 72.4% of carcinogenic risk, which should be treated as \"prior monitoring OPEs\" in further studies. The occurrence and distribution of OPEs in drinking water of China have a good corresponding relationship with the Aihui-Tengchong Line, and drinking water treatment technology (DWTT) was found to be a key factor. Total OPEs, halogeno-OPEs and alkyl-OPEs in drinking water from advanced DWTT cities were much lower than those of conventional DWTT cities. Compared with conventional DWTT, advanced DWTT could reduce about 65.6% and 36.5% of carcinogenic risk and non-carcinogenic risk of OPEs, respectively. Considering the annual growth of OPEs consumption in China and world, further studies regarding the environmental threat of OPEs are required.