bluuebunny/crossref_metadata_2025 huggingface dataset:
Scaling and Designing Activities of Integral Test Facility for HPR1000 Reactor
Authors: Lu Donghua , Li Liangguo , Su Qianhua , Xing Jun
Published: November 2022

The integral test facility is very useful to study the behavior of the pressurized water reactor (PWR) at accidents. As more and more passive safety techniques were adopted in the reactor system, the integral effect test facilities acted very important role to verify these techniques and the prediction of software. An integral effect test facility for the HPR1000 reactor was designed and constructed based on the scaling analysis. The scaling criteria were derived on the model of natural circulation and blowdown of the constant bulk volume in the primary system. The phenomenon were identified and ranked to ensure the scaling can reproduce them in the test facility as the same as the prototype does. The height ratio is 1:4 and the diameter ratio is 1:6 for the test facility. Totally 177 simulators were used to simulate the thermal hydraulics of the fuel assemblies in the practical reactor core. This makes the core keep the same array as the prototype. Each simulator has one electrical heater which power is controlled by the computer. The power of the core has axial cosine profile and three radial zones to reproduce the physical non-uniform distribution in the reactor core.
Probabilistic Safety Assessment on Water Intake Blockage of Nuclear Power Plant
Authors: Wu Yan , Feng Bingchen , Meng Gan , Zhang Xiaoming
Published: November 2022

The marine organism outbreak can lead to water intake blockage, system degradation, equipment failure, and even worse, trip or lose of heat-sink event. According to a survey conducted by the American Electric Power Research Institute (EPRI) in 2009, among the 77 plants surveyed, more than 55% of plants suffered unplanned shutdown or unplanned power reduction events caused by water intake blockage. In recent years, several water intakes blockage events caused by marine organism were reported by domestic nuclear power plants. which leaded to power reduction or shutdown event and heat sink SSCs (systems, structures, and components) degrade or failure. These events greatly threaten operation management, equipment maintenance and emergency response of nuclear power plants. Hence, it is necessary to carry out detailed risk assessment on the water intake blockage event caused by marine organism outbreak.

Aiming at a large-sized pressurized water reactor (PWR) nuclear power plant, this paper builds a realistic model to analyze the risk caused by marine organism using PSA (probabilistic safety assessment) method, and obtains quantitative results of the unit. This paper also identifies the problems and deficiencies in plant’s response to the water intake blockage events, and provides us with risk insight to improve the safety level of nuclear power plants combining the analysis results.
The Research and Application of Configuration Risk Management in Daya Bay NPP
Authors: Zhang Kuan , Cheng Changsheng , Guo Dongyuan , Li Qiongzhe , Zhang Heng
Published: November 2022

National Nuclear Safety Administration issuance “The Technical Policy of Nuclear Power Plant Configuration Risk Management” in December 2019 to support the risk management of multiple system/equipment failures and the flexible operation of nuclear power plant (NPP). Subsequently, Suzhou Nuclear Power Research Institute PSA teams and Daya Bay NPP nuclear safety advisory/Operation operator/planning Engineer established a joint project team to study the implementation of configuration risk management. The configuration risk management system framework and operation process have been determined through the in-depth discussion of multiple disciplines and departments, and the trial operation of risk management system has been started in January 2021 to optimize iterative software and implementation processes. This paper introduces the composition of Daya Bay configuration risk management system, the responsibilities of each discipline in the implementation of configuration risk management, the establishment method and results of risk threshold and risk management matrix, the functions of operation and maintenance risk assessment tools, the characteristics of risk calculation engine, the implementation process of operation configuration risk management and maintenance configuration risk management, the problems found during the trial operation, the management measures for subsequent upgrades, so as to provide reference for other NPPs to carry out the configuration risk management.
Overview of AFCEN Non-Linear Benchmark in China – Improving Rules for Vessel Ratcheting Evaluation
Authors: Tan Yu , Shao Xuejiao , Liang Enming , Zuo Shuchun , Lv Feng , Metais Thomas , Liu Han
Published: November 2022

The French nuclear standard, RCC-M 2017 edition, has seen the inclusion of an Appendix on non-linear calculation methods: the Appendix ZC. This non-mandatory Appendix encompasses a set of rules and guidelines which can help the designer perform non-linear analyses. It includes the definition of models adequate to use, fatigue Ke factor optimization methods, etc...

In fatigue analyses per the RCC-M B-3200 paragraph, rules on thermal ratcheting limits are exposed in paragraph B-3234.8. These rules aim at limiting any thermal ratcheting of the structure and the criteria exposed are sometimes difficult to meet, even though there is no threat to safe operation of the concerned equipment.

Non-linear analyses in this case could be used to help meet the criteria but would need extra rules to be defined: these are considered to be added to the Appendix ZC.

In early 2019, an international benchmark effort was launched on this topic. The case is a typical nozzle geometry subjected to both thermal and pressure transients.

In China, some main nuclear entities have taken part in this benchmark effort: NPIC, SNPI, CNPDC and CNPE, along with the coordination of EDF and Yuansuan.

• let participants get familiar with the benchmark and performing linear elastic calculations along with simplified RCC-M code evaluation methods. The outcome is a participant comparison of the respect or not of the code criteria.

• perform an analysis based first on one’s own parameter identification and an Armstrong-Frederick model (with 1 and 2 parameters) and then perform the comparison with a common set of parameters.

• use a defined cyclic stress-strain curve including full hysteresis loops to derive a common identification methodology and compare results.

This paper aims at providing the public with a progress of the benchmark case (using ANSYS and code_aster software), the Chinese participants findings, and recommendations for the structural integrity community on the first two bullet points above.
A Location Algorithm for Orphan Radioactive Source
Authors: Xiao Qianxi , Cai Jiejin
Published: November 2022

In order to reduce the harm to public safety caused by the loss of radioactive sources. A source searching method is proposed to locate orphan gamma source in the environment with obstacles and radiation shielding. The method is divided into two parts: predicting the probability of a radioactive source by Gaussian process regression (GPR) and path planning for the mobile robot using the probabilistic roadmap (PRM) method. The mean function and covariance function of the Gaussian process need to be selected in advance and the hyperparameters are calculated in the training process. Predicted values of GPR are given in the form of Gaussian distribution, which make us able to calculate the probability that there is a radioactive source in the grid and construct a probability map to guide the robot. The path connecting the start grid to the target grid is planned by the PRM method in a very short time, the cost function of A* algorithm in the query phase controls the pattern of the robot. At the beginning of the search, the robot prefers to move to areas with more information, after data above the threshold is detected, the robot switches to the tracking mode, accesses to the radioactive source rapidly. The effectiveness of the proposed method is verified in a simulation experiment in which a 10m × 10m radiation field with five walls is simulated. The searches of gamma point source are all successfully realized in 5 different cases and compared with the total number of discrete grids, the method uses only a small part of the grid data to realize the location. Overall, the results show that the proposed method is efficient for searching and locating orphan radioactive source.
Study on the Influence of Power Reduction Process on the Leakage Rate of Steam Generator
Authors: Zhang Zhao , Yan Jun-Jie , Wang Wen-Bo , Chong Dao-Tong , Su Min-Hua , Wang Zi-Chun , Shen Rong-Fa
Published: November 2022

The steam generator tubes in PWR unit are prone to mechanical damage and corrosion hazard, tube cracks and steam generator leakage often occurs on alloy 600 tubes. Due to the better corrosion resistance of alloy 690, the tube leakage has never occurred in CPR1000 unit. However, based on the systematic study of the alloy 690 behavior in the PWR operation condition, cracks will also occur at the end of burnup life (EOL); in addition, whether the limit leakage value for steam generator operation originating from EDF units under full power operation is valid for CPR1000 unit should be investigated.

For the same critical crack size, in the process of unit power reduction, the change of the pressure difference between the primary and secondary sides of steam generator may cause the leakage rate to exceed the operating limit. An overall model for CPR1000 unit was developed, the changes were investigated of the pressure difference and leakage rate on the primary and secondary sides of the steam generator under different unit load reduction rates, the results showed that for the critical size crack at the bottom of the hot leg, during the load reduction transient process, the calculated leakage rate will exceed the limit value of 44 L/h in the Operating Technical Specifications (OTS) of CPR1000 unit. Finally the corresponding operation strategy was proposed.
Comparative Analysis and Research on Nuclear Power Regulation & Standard System and Standardization Works Among China, the U.S. and Japan
Authors: Liu Shangyuan , Wei Ran , Zhang Shaolin , Wu Feifei , Du Jian
Published: November 2022

As the world’s leading countries in nuclear power fields, China, the United States, and Japan have relatively sound nuclear power regulation and standard systems. The nuclear power standardization works have also been gradually improved and optimized with the iteration of good practices and the feedback of best experience. Nevertheless, it couldn’t be denied that the paths followed by these countries are not exactly same, due to diversities of state institutions and mechanisms, as well as inherently different national politics, history, technology, and culture. Making periodical revisions on development approach, each country establishes unique, well-applicable, self-consistent system framework and operating model.

With a systematic review, this paper will summarize the current R&D of the countries’ nuclear power regulation & standard system, as well as the latest states on the development of standardization works on both domestic and abroad scales, following by some fruitful comparative analyses. Using the literature research method and Differentiation Competitive Strategy methodology, this paper will also critically analysis advantages and shortcomings respectively, which would be helpful to understand the regulation and system operations comprehensively and objectively, for each country. Additionally, inspirations would be brought to seek an opportunity deepening extensive collaborations for the forthcoming nuclear power international standardization works. This paper will make comments and put forward suggestions focusing on strengthening R&D cooperation among multilateral countries. Ultimately, to improve the diversification and interoperability of nuclear emerging technologies and industrial chain, also accelerate global promotion and common prosperity, via the nuclear field standardization approach.
Strategies and Applications of Big Data and AI Technologies in Nuclear Power Public Opinion Prevention and Control System
Authors: Liang Yun , Zhang Shaolin , Liu Shangyuan
Published: November 2022

For the aim of responding to the climate change, countries around the world have successively unveiled policies to reduce carbon emissions, such as the Carbon Peaking and Carbon Neutrality Goals in China and restarting of nuclear power plants in France. As a kind of clean energy, nuclear energy plays a key role in the process of carbon neutrality. However, due to the particularity and the limited communication channels for the public to access nuclear power fields, the group is often influenced by negative feedback during the promotion of nuclear power projects, which obstructs the development of projects. Hereon, keeping abreast of public opinion information and making correct guidance in communications has become an important link in promoting a virtuous circle of the nuclear industry.

This paper studies the framing principle of the nuclear power public opinion prevention and control system, the construction strategy of each module and the application of new technologies, which could realize wide-range collection of public opinions, real-time monitoring, simulation sorting out context of events based on hot words, correcting simulation deviations by the system based on machine learning results, also, providing early warning of in-time monitoring results. The findings of this research organically integrate the new public opinion prevention and control technology with public communication, which is an exploration of the application of new information technology in the field of public communication.
Oxidation Behaviour of CZ Alloys Under High Temperature Steam
Authors: Chen Minli , Gao Changyuan , Zhang Guoliang , Shi Lin , Chen Liutao , Tan Jun
Published: November 2022

CZ Alloys, including CZ1 and CZ2, are new advanced zirconium alloys developed by China General Nuclear Power Group. This paper presents the oxidation behaviour of CZ Alloys and Zircaloy-4 in flowing steam. A SETSYS Evolution TGA (ThermoGravimetric Analyzer) is used for the high temperature testing. The weight gain of specimens was measured real time in the temperature range of 800∼1200 °C for 3000∼5000s. The hydrogen content after oxidation at 1000 °C was measured. CZ1 (Zr-Sn-Nb alloy), CZ2 (Zr-Nb alloy) and Zircaloy-4 (Zr-Sn alloy) claddings which contain different types of alloying elements have similar oxidation behaviour at above 1100°C but show significant difference at lower temperatures. The weight gain of CZ Alloys are compared with high-temperature oxidation parabolic rate laws of fuel cladding materials which have been used in many LOCA analyses, the Baker-Just equation and the Carthcart-Pawel equation. The results show that the Baker-Just equation is conservative for CZ Alloys and the Carthcart-Pawel equation is more accurate at above 1100°C. The oxidation rate constant and the rate exponent are calculated at each temperature by non-linear fittings.
Application Research on Human Reliability Analysis Method of Class A Human Action of China Fast Reactor
Authors: Niu Jingjuan
Published: November 2022

According to the current situation of human reliability analysis of China fast reactor, combined with the operation experience of China Experimental Fast Reactor (CEFR), this study not only identifies the method of important personnel actions, but also standardizes the technical process of human reliability analysis. Compared four kinds methods of human reliability analysis, finally, the ASEP method is choose for CLASS A, According to the mathematical model of this methods, the calculation code for system analysis is developed using Visual Basic language. Based the standardization of the technical process, the code using examples for CLASS A are provided, finally the standard technical documentation of HRA is edited. Based on the results of the calculation analysis, some recommendations are provided for systems design, man-machine interface design, regulation design and training program. The above is only an example. In the future, it is necessary to analyze more human actions of CLASS C, so as to give suggestions on the impact of human factors in various fields. To achieve the goal of minimize the impact of CLASS C human actions on the design and application of the whole project.
The Research of Corrosion Resistance of CZ2 Zirconium Alloy Welding Specimens
Authors: Xu Yang , Chen Liu-Tao , Gao Chang-Yuan , Tan Jun , Shi Lin
Published: November 2022

Zirconium alloys are one of the main cladding materials in pressurized water reactors. Corrosion resistance of zirconium alloy cladding weld is one of the most important factor affecting fuel integrity. CZ zirconium alloys have been recently developed for advanced PWR fuel assemblies which are designed by China General Nuclear Power Group (CGN). There are two kinds of zirconium alloys, designated as CZ1 and CZ2 respectively. CZ1 is Zr-Sn-Nb alloy, and CZ2 is Zr-Nb alloy. In this paper, the autoclave corrosion test of CZ2 zirconium alloy welded specimen was executed. Then, the corrosion resistance of CZ2 zirconium alloy welding specimens was evaluated by analyzing the the appearance, corrosion weight gain and oxide film thickness. The result shows that corrosion resistance trend of combination of CZ2 and CZ2, CZ2 and Zr-4 welding specimens is basically the same under the conditions of 360 °C /18.6 MPa deionized water and 400 °C /10.3 MPa superheated steam. There was no obvious difference due to different hydro-chemistry. The corrosion resistance of CZ2 and Zr-4 welding specimens is better than that of CZ2 and CZ2 welding specimens. Therefore, the use of Zr-4 end plug material can reduce the sensitivity of CZ2 alloy to heat effect and improve the corrosion resistance of CZ2 alloy cladding.
Hydrogen Loading System for Thin Films for Betavoltaics
Authors: Cheu Darrell , Adams Thomas , Revankar Shripad
Published: November 2022

Betavoltaics are direct conversion energy devices that are ideal for low, micropower and long-lasting, uninterruptable applications. Betavoltaics operate similarly to photovoltaics where a radioisotope irradiates beta particles into a semiconductor p-n junction that converts the kinetic energy into electrical energy. Betavoltaics are limited by their power output from the radioiso-tope. The source density can be increased by the selection of solid-state substrates. While solid-state substrates can be selected from simulations, the viability of the substrate to absorb tritium has to evaluated. The development of a hydrogen loading system was performed to evaluate different film types to understand how they perform during the hydrogen/tritium loading process. The hydrogen loading system utilizes the Sievert method, where the initial pressure and volume is constant and pressure drop in the system is used to determine hydrogen uptake of a film substrate. The procedures of the hydrogen loading system are detailed. To test the procedures of the hydrogen loading system, old, palladium films were loaded. Results show uptake of hydrogen by the thin palladium films, as well as cycles of hydrogen absorption and desorption. Hydrogen loading of palladium was compared to a prior result and was shown to have similar results.
A Study on Removal Mechanisms of Cesium Aerosol From Noble Gas Bubble in Sodium Pool (III) Measurement of Decontamination Factors in Water Simulation Test
Authors: Koie Ryusuke , Kawaguchi Munemichi , Miyahara Shinya , Uno Masayoshi , Seino Hiroshi
Published: November 2022

In a postulated accident of fuel pin failure of a sodium-cooled fast reactor, a fission product of cesium will be released from the failed pin as an aerosol such as cesium iodide and/or cesium oxide together with a fission product noble gas such as xenon and krypton. The xenon and krypton released with the cesium aerosols into the sodium coolant as bubbles have an influence on the removal of cesium aerosols by the sodium pool in a period of bubble rising to the sodium pool surface. Then, the cesium aerosols could transfer into the containment vessel as an initial inventory of a source term. To meet this target, we have developed the computer program AESOP that deals with the expansion and the deformation of the bubble together with the aerosol absorption and researched the sensitivities of the physical parameters on decontamination factor (DF) of cesium aerosols such as the initial bubble diameter, sodium pool depth, and temperature, aerosol particle diameter, and density, initial aerosol concentration in the bubble in previous our papers.

In this study, we performed a water simulation test to measure the DFs of simulant aerosols with nitrogen gas bubbles rising through the water pool for the code validation. The experiments revealed that the DFs increased with the increase in the aerosol diameter and the water pool depth.
Relevant Parameters Influencing the Labile Contamination and the Removal Factor
Authors: Agullo Pierrick , Gossard Alban , Ranchoux Gilles , Petitot Fabrice , Porcheron Emmanuel
Published: November 2022

Several nuclear facilities are currently dismantling in France, namely on CEA’s and EDF’s sites. The whole decommissioning and dismantling, cutting operations and nuclear waste management can significantly affect worker risks. In this context, this work aims to better assess the internal exposure risks for operations where removal factor and airborne release factor play an essential part in the uncertainties. For that purpose, developing a new method for assessing the risk of internal exposure is necessary to optimize the choice of Personal Protective Equipment during nuclear dismantling.

Based on a bibliographic study and feedback, we identified most of the forces and parameters that influence labile contamination removal and resuspension. Their high number forced us to highlight the most relevant ones regarding data from the bibliography and worksite reality. Thus, the role of the drying temperature, relative humidity, roughness of the contaminated surface and the swiping pressure were particularly studied on the assessment of the labile contamination and the removal factor. For that, we performed successive wiping operations with cotton wipes on surface on which a simulated labile contamination was deposited to estimate the influence of different parameters on the total labile contamination and the removal factor. Particularly, we noticed the consequences of roughness on these latter.
A Step Towards Rules to Identify Bounding Conditions in Terms of Fatigue Damage for NPP Operational Transients
Authors: Lv Feng , Zhou Zhengyu , Chen Zhilin , Liu Han , Zheng Zihao
Published: November 2022

Mechanical components of nuclear power plant are subject to variations in temperature and pressure, which cause stress and ultimately induce fatigue damage. Usually, these variations, called operational transients, are well identified through the use of sensors and can be easily classified into design transients and associated to different reactor states and functional situations. However, a number of operational transients cannot be covered by the corresponding design transients due to temperature or pressure parameters exceeding the defined surveillance thresholds. In that case, an alternative is to find a more severe design transient to cover the operational transient, and then justify the existing design fatigue analysis remain valid. This process is today not existent in design standards and partially mentioned in standards such as RSE-M, yet it is critical for the safe operation of plants especially in the domain of Long Term Operation (LTO). In this paper, a set of mechanical criteria is developed to compare the severity between transients, which include four aspects: maximum stress state, minimum stress state, alternating stress intensity and fatigue damage. A three-dimensional rain flow method is used to identify extreme stress state and to detect multiaxial stress peak and valley. As an example, a typical nozzle is assumed to endure a non-classified operational transient. The envelope analysis for this transient classification is demonstrated and a design transient is selected to cover the operational transient. The numerical simulation results show that if a design transient and an operational transient satisfy the mechanical criteria strictly, then the operational transient can be bounded by the design transient. The proposed mechanical criteria are consistent with the requirements of the RCCM and RSE-M codes in term of preventing fatigue damage.
Potential Crud Related Margin Gains With Chromium Coated Zirconium Cladding
Authors: Byers William A. , Wang Guoqiang
Published: November 2022

The build-up of deposits (Crud) on fuel cladding can cause several issues for PWRs. The crud becomes activated and is transported to other locations in the RCS increasing radiation fields, it can collect boron causing power shifts (CIPS, Crud Induced Power Shifts) and if thick enough localized corrosion will be increased (CILC, Crud Induced Localized Corrosion). The application of a chromium coating to zirconium alloy cladding is being pursued to improve the corrosion performance of the cladding both during normal operation and in the event of accident conditions producing high cladding temperatures. The change will also influence the crud affinity of the cladding. The deposition of corrosion products from the ex-core portions of the plant will be altered. Also, corrosion of the cladding itself contributes to the crud burden in a PWR, and this factor will undoubtedly change with the application of a chromium coating. Changes in the surface texture produced by the coating will also influence crud deposition by changing boiling nucleation and thermal hydraulic factors.

This paper discusses how a change to chromium coated fuel cladding will likely affect crud deposition and will give the results of crud deposition testing of chromium coated cladding in the WALT loop.
3d Multi-Physics Numerical Coupling of Monte Carlo Neutronics and Thermal-Hydraulic for Solid Core
Authors: Yang Qing , Xia Jianhua , Liu Xiaojing , Pan Qingquan , He Hui , Zhang Tengfei
Published: November 2022

In recent years, more and more attention has been paid to the refinement and authenticity of models in nuclear reactor design and safety analysis. In the numerical simulation of the reactor, both neutron and thermal-hydraulics have a great influence on the calculation results. At the same time, because the neutron energy spectrum and the power distribution of the reactor strongly depend on the thermal-hydraulic properties of the coolant, neutronic and thermal-hydraulic coupling (N/TH) allows for a more precise analysis of the reactor. In this paper, based on the Picard method, a set of implicit and high-precision neutronic and thermal-hydraulic coupling codes is developed, which connects the Monte Carlo code RMC (Reactor Monte Carlo code) and the computational fluid dynamics code STAR-CCM+, processes the files and data generated during the coupling process, and transfers them to thermal-hydraulic and neutron simulation. The accuracy and reliability of the coupling code developed in this paper are verified by comparing it with the calculation results of the single rod model of the University of Illinois at Urbana-Champaign (UIUC). In this paper, a conceptual design of a lead-bismuth-cooled solid reactor is proposed, and an optimal design is obtained through the multidimensional and full-scale optimization of the reactor. Then the coupling code developed in this paper is used for coupling simulation to study its neutron and thermal-hydraulic properties under various transient conditions.
Associations Between Physical Activity and Gross Motor Skills in Parent–Child Dyads
Authors: Scott-Andrews Katherine Q. , Hasson Rebecca E. , Miller Alison L. , Templin Thomas J. , Robinson Leah E.
Published: November 2022

This study examines the associations of physical activity and gross motor skills in parent–child dyads. Parent–child dyads (N = 61, 84% mothers, children aged 8–11 years) participated in this study. Anthropometrics were self-reported through Qualtrics. Physical activity was assessed using accelerometers. Motor skills were measured through four skills: catch, kick, throw, and jump. These skills were assessed using process (i.e., performance criteria of the Test of Gross Motor Development-3) and product (i.e., catch percentage and jump distance) measures. A complete motor skill score was computed by standardizing both process and product scores and summing them. Correlation coefficients and ordinary least square regressions were computed to examine the associations of physical activity and motor skills. Parents’ and children’s moderate to vigorous physical activity were significantly associated (β = 0.30 ± 0.11; p = .008). Parents’ and children’s motor skills were significantly associated (β = 0.46 ± 0.18; p = .012). Understanding parent determinants can support effective interventions targeting children’s low physical activity levels and improving motor competence. Our results highlight the importance of parents’ physical activity and motor skills, which are significantly associated with those of their children. These parent factors may be a key consideration for effective family-based physical activity interventions.
Salt-induced ductilization and strain-insensitive resistance of an intrinsically conducting polymer
Authors: He Hao , Chen Rui , Yue Shizhong , Yu Suzhu , Wei Jun , Ouyang Jianyong
Published: November 2022

High mechanical ductility and high mechanical strength are important for materials including polymers. Current methods to increase the ductility of polymers such as plasticization always cause a remarkable drop in the ultimate tensile strength. There is no report on the ductilization of polymers that can notably increase the elongation at break while not lowering the ultimate tensile strength. Here, we report the salt-induced ductilization of an intrinsically conducting polymer, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS). Treating highly conductive PEDOT:PSS with a salt such as sodium perchlorate can enhance its elongation at break from 8.5 to 53.2%, whereas it hardly affects the tensile strength. Moreover, the resistance of the ductilized PEDOT:PSS films is insensitive to the tensile strain before fracture and slightly increases by only ~6% during the cyclic tensile testing with the strain up to 30%. These effects are ascribed to the decrease in the Coulomb attraction between PEDOT
+
and PSS
−
by the salt ions.
Emplacement of the Franklin large igneous province and initiation of the Sturtian Snowball Earth
Authors: Pu Judy P. , Macdonald Francis A. , Schmitz Mark D. , Rainbird Robert H. , Bleeker Wouter , Peak Barra A. , Flowers Rebecca M. , Hoffman Paul F. , Rioux Matthew , Hamilton Michael A.
Published: November 2022

During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth’s thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. Geologic observations and (U-Th)/He dates on Franklin sills are compatible with major post–Franklin exhumation, possibly due to development of mafic volcanic highlands on windward equatorial Laurentia and increased global weatherability. After a transient magmatic CO
2
flux, long-term carbon sequestration associated with increased weatherability could have nudged Earth over the threshold for runaway ice-albedo feedback.
ZMP recruits and excludes Pol IV–mediated DNA methylation in a site-specific manner
Authors: Wang Yuan , Le Brandon H. , Wang Jianqiang , You Chenjiang , Zhao Yonghui , Galli Mary , Xu Ye , Gallavotti Andrea , Eulgem Thomas , Mo Beixin , Chen Xuemei
Published: November 2022

In plants, RNA-directed DNA methylation (RdDM) uses small interfering RNAs (siRNAs) to target transposable elements (TEs) but usually avoids genes. RNA polymerase IV (Pol IV) shapes the landscape of DNA methylation through its pivotal role in siRNA biogenesis. However, how Pol IV is recruited to specific loci, particularly how it avoids genes, is poorly understood. Here, we identified a Pol IV–interacting protein, ZMP (zinc finger, mouse double-minute/switching complex B, Plus-3 protein), which exerts a dual role in regulating siRNA biogenesis and DNA methylation at specific genomic regions. ZMP is required for siRNA biogenesis at some pericentromeric regions and prevents Pol IV from targeting a subset of TEs and genes at euchromatic loci. As a chromatin-associated protein, ZMP prefers regions with depleted histone H3 lysine 4 (H3K4) methylation abutted by regions with H3K4 methylation, probably monitoring changes in local H3K4 methylation status to regulate Pol IV’s chromatin occupancy. Our findings uncover a mechanism governing the specificity of RdDM.
Multicatalysis protocol enables direct and versatile enantioselective reductive transformations of secondary amides
Authors: Chen Hang , Wu Zhi-Zhong , Shao Dong-Yang , Huang Pei-Qiang
Published: November 2022

The catalytic asymmetric geminal bis-nucleophilic addition to nonreactive functional groups is a type of highly desirable yet challenging transformation in organic chemistry. Here, we report the first catalytic asymmetric reductive/deoxygenative alkynylation of secondary amides. The method is based on a multicatalysis strategy that merges iridium/copper relay catalysis with organocatalysis. A further combination with the palladium-catalyzed alkyne hydrogenation allows the one-pot enantioselective reductive alkylation of secondary amides. This versatile protocol allows the efficient synthesis of four types of α-branched chiral amines, which are prevalent structural motifs of active pharmaceutical ingredients. The protocol also features excellent enantioselectivity, chemoselectivity, and functional group tolerance to be compatible with more reactive functional groups such as ketone and aldehyde. The synthetic utility of the method was further demonstrated by the late-stage functionalization of two drug derivatives and the concise, first catalytic asymmetric approach to the κ-opioid antagonist aticaprant.
Building Connections to Biology and Community through Service-Learning and Research Experiences
Authors: Kulesza Amy E. , Imtiaz Safa , Bernot Kelsie M.
Published: November 2022

Service-learning and undergraduate research experiences are high-impact practices that have become more common in the sciences, but the benefits of short-term experiences have not been thoroughly investigated. The purpose of this study was to compare within-semester gains for students in a short-term service-learning (SL) or short-term research project (RP) in terms of students’ (i) motivation to learn biology, (ii) scientific literacy, (iii) perception of the relevance of biology to their lives, and (iv) learning gains associated with course learning outcomes.
PIK-24 Inhibits RSV-Induced Syncytium Formation via Direct Interaction with the p85α Subunit of PI3K
Authors: Chen Li-Feng , Xu Wei-Bin , Xiong Si , Cai Jun-Xing , Zhang Jing-Jing , Li Yao-Lan , Li Man-Mei , Zhang Hong , Liu Zhong
Published: November 2022

PI3K protein has many functions and regulates various cellular processes. As an important regulatory subunit of PI3K, p85α can regulate the activity of PI3K signaling.
Assessing the impact of the phase-out measures during COVID-19 pandemic, using regression models: a longitudinal observational study
Authors: Pardo Maria Carmen , Pérez Teresa
Published: November 2022

Objective

To assess the impact of different phase-out measures approved by several European governments.

Design

This is a longitudinal observational study.

Settings

European countries, from 20 February 2020 to 11 May 2020.

Participants

All European countries that implemented at least one phase-out measure dictated by governments, during the follow-up period.

Main outcome

New COVID-19 cases, analysed as daily rate by countries.

Methods

We compared the observed versus the predicted rates of new confirmed cases, hospital admission, intensive care unit (ICU) admission and deaths by regions in Spain, to assess the accuracy of the proposed generalised estimating equations and hurdle models. Based on these models, we defined and calculated two indices to quantify the impact of the phase-out measures approved in several European countries.

Results

After 2-month follow-up, we confirmed the good performance of these models for the prediction of the incidence of new confirmed cases, hospital admission, ICU admission and death in a 7-day window. We found that certain phase-out measures implemented in Italy, Spain and Denmark showed moderate impact in daily new confirmed cases. Due to these different phase-out measures, in Italy, the estimated increment of new confirmed cases per 100 000 inhabitants was 4.61, 95% CI (4.42 to 4.80), in Spain 2.58, 95% CI (2.54 to 2.62) and in Denmark 2.55, 95% CI (2.40 to 2.69). Other significant measures applied in other countries had no impact.

Conclusion

The two indices proposed can be used to quantify the impact of the phase-out measures and to help other countries to make the best decision. Monitoring these phase-out measures over time can minimise the negative effects on citizens.
Prevalence of atrial fibrillation in Northern Sri Lanka: a study protocol for a cross-sectional household survey
Authors: Kanesamoorthy Shribavan , Sheron Vethanayagam Antony , Uruthirakumar Powsiga , Kodippily Chamira , Kumarendran Balachandran , Gooden Tiffany E , Thomas Graham Neil , Nirantharakumar Krishnarajah , Lip Gregory Y H , Guruparan Mahesan , Haniffa Rashan , Surenthirakumaran Rajendra , Beane Abi , Subaschandran Kumaran
Published: November 2022

Introduction

Atrial fibrillation (AF) is the most common arrhythmia globally. It is associated with a fivefold risk in stroke, but early diagnosis and effective treatment can reduce this risk. AF is often underdiagnosed, particularly in low-income and middle-income countries (LMICs) where screening for AF is not always feasible or considered common practice in primary care settings. Epidemiological data on AF in LMICs is often incomplete particularly in vulnerable populations. This LMIC research collaborative aims to identify the prevalence of AF in the Northern Sri Lankan community.

Methods and analysis

A cross-sectional household survey piloted and codesigned through a series of community engagement events will be administered in all five districts in Northern Province, Sri Lanka. A multistage cluster sampling approach will be used starting at district level, then the Divisional Secretariats followed by Grama Niladhari divisions. Twenty households will be selected from each cluster. The study aims to recruit 10 000 participants aged 50 years or older, 1 participant per household. Demographic and socioeconomic characteristics, well-being and lifestyle and anthropometric measurements will be collected using a digital data platform (REDCap, Research Electronic Data Capture) by trained data collectors. Participants will be screened for AF using a fingertip single-lead ECG via a smartphone application (AliveCor) with rhythm strips reviewed by a consultant cardiologist. Prevalence of AF and risk factors will be established at province and district-levels. Adjusted ORs and population attributable fractions for AF risk factors will be determined.

Ethics and dissemination

This study was approved by the Ethics Review Committee of Faculty of Medicine at University of Jaffna. Written informed consent will be obtained from all participants. Findings will be disseminated through publication in a peer-reviewed journal and presentations at conferences. The findings will enable early treatment for new AF diagnoses and inform interventions to improve community-based management of AF in LMICs.
Prevalence of skin pressure injury in critical care patients in the UK: results of a single-day point prevalence evaluation in adult critically ill patients
Authors: Rubulotta Francesca , Brett Stephen , Boulanger Carole , Blackwood Bronagh , Deschepper Mieke , Labeau Sonia O , Blot Stijn
Published: November 2022

Objectives

Hospital-acquired pressure injuries (PIs) are a source of morbidity and mortality, and many are potentially preventable.

Design

This study prospectively evaluated the prevalence and the associated factors of PIs in adult critical care patients admitted to intensive care units (ICU) in the UK.

Setting

This service evaluation was part of a larger, international, single-day point prevalence study of PIs in adult ICU patients. Training was provided to healthcare givers using an electronic platform to ensure standardised recognition and staging of PIs across all sites.

Participants

The characteristics of the ICUs were recorded before the survey; deidentified patient data were collected using a case report form and uploaded onto a secure online platform.

Primary and secondary outcome measures

Factors associated with ICU-acquired PIs in the UK were analysed descriptively and using mixed multiple logistic regression analysis.

Results

Data from 1312 adult patients admitted to 94 UK ICUs were collected. The proportion of individuals with at least one PI was 16% (211 out of 1312 patients), of whom 8.8% (n=115/1312) acquired one or more PIs in the ICU and 7.3% (n=96/1312) prior to ICU admission. The total number of PIs was 311, of which 148 (47.6%) were acquired in the ICU. The location of majority of these PIs was the sacral area, followed by the heels. Braden score and prior length of ICU stay were associated with PI development.

Conclusions

The prevalence and the stage of severity of PIs were generally low in adult critically ill patients admitted to participating UK ICUs during the study period. However, PIs are a problem in an important minority of patients. Lower Braden score and longer length of ICU stay were associated with the development of injuries; most ICUs assess risk using tools which do not account for this.

Trial registration number

NCT03270345.
The General Self-Efficacy Scale in a population planned for bariatric surgery in Sweden: a psychometric evaluation study
Authors: Dahlberg Karuna , Stenberg Erik , Liang Yuli , Nilsson Ulrica , Jaensson Maria
Published: November 2022

Objectives

This study psychometrically evaluated General Self-Efficacy (GSE) Scale in patients planned for bariatric surgery in Sweden.

Design

A cross-sectional psychometric study. The psychometric evaluation was guided by the COnsensus-based Standards for the selection of health status Measurement Instruments checklist for health-related reported-patient outcomes.

Setting

Three bariatric centres in Sweden.

Participants

Adult patients≥18 years old scheduled for primary bariatric surgery (with sleeve gastrectomy or Roux-en-Y gastric bypass).

Primary and secondary measures

Psychometric properties of the GSE.

Results

In total, 704 patients were included in the analysis. Mean values for GSE items were 2.9–3.4 and the mean GSE sum score was 31.4 (SD 4.7). There were no floor or ceiling effects. Cronbach’s alpha was 0.89. Men reported a higher mean GSE than did women, that is, 31.2 (SD 4.8) for women versus 32.1 (SD 4.3) for men, p=0.03. Correlation coefficients were weak or negligible: GSE and mental component summary score of 36-Item Short Form Health Survey (SF-36)/RAND 36, r=0.18 (p<0.00); GSE and physical component summary score of SF-36/RAND 36, r=0.07 (p=0.138); GSE and obesity-related problem scale r=−0.15 (p=0.001) and GSE and level of education, r=0.04 (p=0.35). Confirmatory factor analysis indicated a one-factor construct with a satisfactory goodness of fit, that is, Comparative Fit Index=0.927, root mean square error of approximation=0.092 and standardised root mean square residual=0.045. The factor GSE explained almost half or over half of the variance of each item (0.45–0.75, p-values<0.001).

Conclusions

The GSE scale is a valid and reliable scale that can be used to assess general self-efficacy in patients undergoing bariatric surgery.
Acute coronary syndrome screening in patients presenting with arteriosclerosis in health check-ups: a case–control study
Authors: Li Xiaoxing , Yan Fangkun , Liu Xinhui , Li Mingzhuo , Li Jiangbing , Chen Yuguo , Li Chuanbao
Published: November 2022

Objectives

This research aimed to develop a simple and effective acute coronary syndrome (ACS) screening model in order to intervene early and focus on prevention in patients presenting with arteriosclerosis.

Design

A case–control study.

Setting

The study used a cross-sectional survey to collect data from 2243 patients who completed anonymous electronic medical record (EMR) data and coronary angiography was gathered at a hospital in Shandong Province between December 2013 and April 2016.

Participants

Adults 18 years old and above diagnosed as ACS or non-ACS according to the records in hospital EMR database, and with completed basic information (age and sex).

Predictors

54 laboratory biomarkers and demographic factors (age and sex).

Statistical analysis

A dataset without missing data of all patients' laboratory indicators and demographic factors was divided into training set and validation set after being balanced. After the training set balanced, area under the curve of random forest (AUCRF) and least absolute shrinkage and selection operator (LASSO) regression were used for feature extraction. Then two set random forest models were established with the different feature sets, and the process of comparison and analysis was made to evaluate models for the optimal model including sensitivity, accuracy and AUC receiver operating characteristic curves with the internal validation set.

Main outcome measures

To establish an ACS screening model.

Results

An RF model with 31 features selected by LASSO with an AUC of 0.616 (95% CI 0.650 to 0.772), a sensitivity of 0.832 and an accuracy of 0.714 in the validation set. The other RF model with 27 features selected by AUCRF with an AUC of 0.621 (95% CI 0.664 to 0.785), a sensitivity of 0.849 and an accuracy of 0.728 in the validation set.

Conclusions

The established ACS screening model with 27 clinical features provides a better performance for practical solution in predicting ACS.