bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Cooling Process in a Reactor Vessel of Sodium-Cooled Fast Reactor Under Severe Accident: Velocity Measurement Experiments Simulating Operation of Decay Heat Removal Systems
Authors: Tsuji Mitsuyo , Aizawa Kosuke , Kobayashi Jun , Kurihara Akikazu , Miyake Yasuhiro
Published: October 2020

In Sodium-cooled Fast Reactors (SFRs), it is important to optimize the design and operate decay heat removal systems for safety enhancement against severe accidents which could lead to core melting. It is necessary to remove the decay heat from the molten fuel which relocated in the reactor vessel after the severe accident. Thus, the water experiments using a 1/10 scale experimental apparatus (PHEASANT) simulating the reactor vessel of SFR were conducted to investigate the natural circulation phenomena in a reactor vessel. In this paper, the natural circulation flow field in the reactor vessel was measured by the Particle Image Velocimetry (PIV) method. The PIV measurement was carried out under the operation of the dipped-type direct heat exchanger (DHX) installed in the upper plenum when 20% of the core fuel fell to the lower plenum and accumulated on the core catcher. From the results of PIV measurement, it was quantitatively confirmed that the upward flow occurred at the center region of the lower and the upper plenums. In addition, the downward flows were confirmed near the reactor vessel wall in the upper plenum and through outermost layer of the simulated core in the lower plenum. Moreover, the relationship between the temperature field and the velocity field was investigated in order to understand the natural circulation phenomenon in the reactor vessel. From the above results, it was confirmed that the natural circulation cooling path was established under the dipped-type DHX operation.
Numerical Simulation of Multi-Physics Processes in Nuclear System Based on Galerkin Finite Element Method
Authors: Yuan Baoxin , Yang Wankui , Zhang Songbao , Zhong Bin , Wei Junxia , Ying Yangjun
Published: October 2020

It is of practical significance to analyze the multi-physics process of nuclear system, which includes neutronics, heat transfer and thermoelasticity. Fission reaction is the heat source in system, the heat source will affect the distribution of temperature field, which will lead to the change of strain. Strain in turn will affect the distribution of neutron field. Therefore, it is necessary to analyze the distribution of neutron flux, temperature and strain in system. Three aspects of work have been carried out: 1) Based on Galerkin finite element theory, the governing equations of neutronics, heat transfer and thermoelasticity are established; 2) The multi-physics analysis code is developed; 3) The calculation results are analyzed and discussed.
Numerical Study of Fuel Melting and Molten Migration Based on the MPS Method
Authors: Lei Zhong , Deng Jian , Li Wei , Wu Xiaoli , Deng Chunrui
Published: October 2020

Core melting and molten migration behavior are hot and difficult issues in the field of nuclear reactor severe accident research. The Moving Particle Semi-implicit (MPS) meshless method has potential to simulate free-surface and multiphase flows. In this study, the MPS method was utilized to simulate the melting process of UO2-Zr rod-type fuel elements. The models of heat conduction with phase change, simplified UO2-Zr eutectic reaction, viscous flow and surface tension were implemented with the framework of standard MPS method. Then, the improved MPS code was used to simulate and analyze the process of high-temperature melting and characteristics of molten migration and solidification in the coolant channel, aiming at revealing the severe accidents for light water reactors (LWR), particularly the early core damage. The results showed that compared with the case of higher initial temperature, when the initial temperature of molten UO2 is lower, more molten UO2 will solidify on the surface of rod cluster, and the blockage of upper flow channel caused by molten UO2 is more serious. In addition, this study also demonstrated the potential of the MPS method for the study of complicated severe accident phenomena in not only traditional LWR but also advanced nuclear reactors in the future.
Development and Assessment of Data-Driven Digital Twins in a Nearly Autonomous Management and Control System for Advanced Reactors
Authors: Lin Linyu , Rouxelin Pascal , Athe Paridhi , Dinh Nam , Lane Jeffrey
Published: October 2020

A critical component of the autonomous control system is the implementation of digital twin (DT) for diagnosing the conditions and prognosing the future transients of physical components or systems. The objective is to achieve an accurate understanding and prediction of future behaviors of the physical components or systems and to guide operating decisions by an operator or an autonomous control system. With specific requirements in the functional, interface, modeling, and accuracy, DTs are developed based on operational and simulation databases. As one of the modeling methods, data-driven methods have been used for implementing DTs since they have more adaptive forms and are able to capture interdependencies that can be overlooked in model-based DTs.

To demonstrate the capabilities of DTs, a case study is designed for the control of the EBR-II sodium-cooled fast reactor during a single loss of flow accident, where either a complete or a partial loss of flow in one of the two primary sodium pumps is considered. Based on the definition of DTs and the design of autonomous control system, DTs for diagnosis and prognosis are implemented by training feedforward neural networks with suggested inputs, training parameters, and knowledge base. Furthermore, inspired by the validation and uncertainty quantification scheme for scientific computing, a list of sources of uncertainty in input variables, training parameters, and knowledge base is formulated. The objective is to assess qualitative impacts of different sources of uncertainty on the DT errors. It is found that the performance of DT for diagnosis and prognosis satisfies the acceptance criteria within the training databases. Meanwhile, the accuracy of DTs for diagnosis and prognosis is highly affected by multiple sources of uncertainty.
Research on Analysis and Modeling Methods for LBLOCA in Nuclear Power Plants Based on Autonomous LOCA Analysis Platform ARSAC
Authors: Zhou Jiayue , Wu Dan , Ding Shuhua , Jiang Guangming
Published: October 2020

In order to meet the demand of continuous innovation of technologies and the general trend of autonomous nuclear power plants design and export of nuclear power plants, it is necessary to develop an autonomous LOCA analysis platform and corresponding analysis methods for the most complex design basis accidents. In this paper, the characteristics of LOCA analysis platform ARSAC, designed by Nuclear Power Institute of China, and the code ARSAC-K which meets the requirements of the US Federal Code 10 CFR 50.46 Appendix K model are introduced as well as a set of LOCA analysis methods and modeling methods. Based on the international advanced LOCA analysis code development concept, the code ARSAC has made new breakthroughs in matrix algorithms, key thermal hydraulic models and so on. Validation work has also been carried out in-depth. A set of advanced LOCA analysis methods has been developed using code ARSAC-K and advanced power plant parameter sampling methods. Analysis on LBLOCA of nuclear power plants with code ARSAC-K was performed, and the impact of different modeling methods on the LOCA analysis results was studied. To ensure the rationality and conservativeness of the analysis results, a set of reasonable and conservative modeling methods is fixed on the basis of a large number of sensitivity analyses for subsequent analysis and calculation. In the future, a lot of optimization work will be done to improve the LOCA code and corresponding methods.
Uncertainty Quantification of Seismic Response of Reactor Building Considering Different Modeling Methods
Authors: Choi Byunghyun , Nishida Akemi , Muramatsu Ken , Itoi Tatsuya , Takada Tsuyoshi
Published: October 2020

After the 2011 Fukushima accident, the seismic regulations for nuclear power plants (NPP) in Japan have been strengthened to include countermeasures far beyond design-basis accidents. The importance of seismic probabilistic risk assessments, therefore, have been the focus of deserved attention. Generally, an uncertainty quantification has been a very important undertaking to assess for fragility in NPP buildings. Therefore, this study focuses on the reduction in epistemic uncertainty by aiming to clarify the seismic-response effects on NPP buildings based on different modeling methods. As a first step in this study, the authors compared the seismic-response effects using two modeling methods of analysis. To evaluate the seismic response, an analysis was performed on two building model types; these being the three-dimensional (3D) finite-element model and the sway-rocking model with a conventional lumped mass system. To input a ground motion, the authors adopted 200 types of simulated seismic ground motions, generated by fault-rupture models, using stochastic seismic source characteristics. For the uncertainty quantification, we conducted a statistical analysis of the seismic responses acquired from the two modeling methods based on the building response each ground-motion input, and quantitatively evaluated the uncertainty response by considering the different modeling methods. We found a clear difference in the modeling methods near the floor and wall openings. We also imparted our knowledge on these 3D effects for the seismic-response analysis.
Analytical Justifications As Part of the “Post-Fukushima” Upgrades Implementation on Zaporizhzhya NPP Unit 1
Authors: Mazurok Oleksandr , Ivanov Vadym , Kocharyants Oleg
Published: October 2020

In accordance with a complex program to improve the safety of Ukrainian NPP units, a number of “Post-Fukushima” upgrades are being implemented. The upgrades were identified based on the results of “stress-tests” performed after the severe accident at the NPP Fukushima Daiichi (Japan) and aimed at preventing or managing a severe accident. As part of the implementation of upgrades for the possibility of installation and commissioning of new equipment, in accordance with regulatory documentation, is required confirmation that the upgrade will not lead to a degradation of the NPPs safety. For this purpose, the safety analysis report and analytical calculations, including thermal-hydraulic, probabilistic and radiation analysis, are developed. In this paper, on the example of “Post-Fukushima” upgrades, the practical experience of performing analytical calculations in order to justify the safety of Ukrainian NPP power units is described. As an example, Zaporizhzhya NPP Unit 1 (reactor facility type: VVER-1000/V320, reactor type: PWR VVER-1000, operational electric power: 1000 MW) was chosen, which is a pilot for the implementation of “Post-Fukushima” upgrades in Ukraine mainly. In this paper, on the example of “Post-Fukushima” upgrades, the practical experience of performing analytical calculations in order to justify the safety of pilot unit is described.

Company ES Group and its employees took part in the implementation of most upgrades by supporting domestic and foreign companies, as well as the NPP operator, for the successful implementation of upgrades using the best technical solutions and modern calculation justifications.
Probability of Rupture for WWER-1000 Main Piping
Authors: Dubyk Yaroslav , Zarazovskii Maksym , Ageiev Sergii , Filonov Vladislav
Published: October 2020

A probability of rupture for WWER-1000 main piping was calculated based on the Failure Assessment Diagram (FAD), treating material properties of welds (the most likely zone for crack growing and its nucleation) and crack morphology parameters as stochastic values. In order to perform probabilistic calculations, Critical Temperature of Brittleness (CTB, WWER’s analogue of PWRs transition temperature which used to index the Fracture Toughness curve) and Yield (Ultimate) Strength as well were fitted by normal distribution, based on experimental data taken from the manufacture documentation of Ukrainian Nuclear Power Plants (NPPs). A set of calculations were conducted for Normal Operating conditions (NOC), Safe Shutdown Earthquake (SSE) and several emergency situations like: shaft jamming of a reactor cooling pump and break of the piping’s, connected to the considered ones (a set of LOCA events). Based on static and dynamic calculations, the most loaded zones were selected, where the cracks were postulated. Crack opening area was calculated according to original developed procedure, which accounts for membrane and linear stress components through the wall thickness. The Henry-Fauske flow model is used with modified parameters accounting for crack morphology as a normally distributed random variable. It is an important part of analysis, since different crack types have great differences in friction, bend protrusion and flow length parameters. The rupture probabilities for Main Circulating Piping were calculated with accounting for thermal aging effect. It was proven, that crack morphology parameters highly affect the leak rate and its distribution becomes more scattered. Among the mechanical characteristic, a Fracture toughness has more influence rather than Ultimate of Yield strength.
Modeling the Flow Redistribution Upstream From the Spacer Grid of a PWR
Authors: de Lambert Stanislas , Cardolaccia Jérome , Faucher Vincent
Published: October 2020

Fuel assemblies’ deformation is an industrial issue that has been first reported in the 90’s. This phenomenon has originally been pointed out for being the explanation of IRI (incomplete rod cluster insertion). Recently, fuel assembly bowing has regained attention for its impact over several core’s management issues, including core neutronics.

When deformation occurs, it tends to alter bypasses geometry around the affected fuel assembly. The water gaps’ thicknesses along the assembly’s height does not match the nominal value anymore. As a result, spacer grids can get closer of farther to the surrounding ones. The redistribution between the bypasses and the grid is then involved, depending on the bypasses’ thicknesses and the grid geometry. This unfolding effect entails differences in pressure laterally along a grid, which thus brings about a lateral hydraulic force exerting on the grid.

The following paper presents a method to esteem this redistribution thanks to an hydraulic network. Hydraulic resistances can be set up according to the bypass thickness. As a result, both pressure and volumetric flow rates can be calculated to further estimate lateral forces.

The approach has been validated with both CFD simulations and an experimental mock-up.
Computational Fluid Dynamics Simulation of a Single-Phase Rectangular Thermosiphon
Authors: Nguyen Tri , Merzari Elia
Published: October 2020

Buoyancy-driven flows are widespread in diverse engineering applications. Such flows have been studied in great detail theoretically, experimentally, and numerically. However, the fluid-dynamic instabilities and flow reversals of thermosiphon are still actively investigated. The presence of such instabilities limits the effectiveness of such devices for decay heat removal.

Traditionally the stability analysis of natural convection loops has been confined to one-dimensional calculations, on the argument that the flow would be mono-dimensional when the ratio between the radius of the loop and the radius of the pipe is much larger than 1. Nevertheless, accurate velocity measurements of the flow in toroidal loops have shown that the flow presents three-dimensional effects. Previous works of the authors have shown that these structures can be seen in thermosiphons. In this paper, we aim to use modern CFD methods to investigate the three-dimensional flow in thermosiphons.

This paper focuses on rectangular thermosiphons. In particular, we perform a series of high-fidelity simulations using the spectral element code Nek5000 to investigate the stability behavior of the flow in a rectangular thermosiphon. We compare the results with available existing experimental data from the L2 facility in Genoa. We examine in detail the flow structures generated.

Moreover, in the past various authors have demonstrated that the overall behavior of the thermosiphon depends strongly on the boundary conditions (BCs). The simulation campaign was carried out with different BCs to investigate and confirm this effect. In particular, simulations with Dirichlet, Neumann and Robin BCs for heater and sink were performed.
Considerations for Development of Probabilistic Assessments for Nuclear Systems and Components
Authors: Pandey Mahesh , Wasiluk Bogdan
Published: October 2020

The risk-informed approach has been increasingly utilized by the nuclear industry and the regulators in Canada and around the world. This involves the assessment of plant risk and the considerations for defence-in-depth, safety margin and other nuclear safety principles. The estimates of reliability metric have been commonly obtained using probabilistic methods that involve distributed inputs. While the engineering focus has typically been on finding a solution for a specific problem, the scientific community and the regulators are concerned with generic principles, foundation of probabilistic approaches and definition of reliability metric used in the assessment. In this paper, the concept of a time-dependent reliability framework is discussed to facilitate selecting the appropriate approach to meet, in principle, the assessment intent. In the end, any probabilistic assessment should be fundamentally meaningful, consistent and transparent to inspire confidence in the public and the regulators.
Analysis of Droplet Impacting on Inclined Wall
Authors: Chen Bowen , Wang Bo , Ke Bingzheng , Li Ru , Tian Ruifeng
Published: October 2020

The steam generator is an important part of the nuclear power plant, and the corrugated plate separator plays the important role of drying steam in the steam generator to improve power generation efficiency and protect the safety of the system. The separation mechanism of the corrugated plate separator is relatively complicated. The droplets are moved by the drag force of the steam and gravity in the corrugated plate separator, and captured by the wall of the corrugated plate separator. When the velocity is increased, the inertial force of droplet is increased, so that the droplet is more easily captured by the wall of the corrugated plate separator, and the separation efficiency of the corrugated plate separator is increased. In this paper, the phenomenon of droplet impact on the inclined wall is studied by high-speed photography technology, and the cause and mechanism of the phenomenon are analyzed. By analyzing the spreading and splashing on the droplets impacting on the inclined wall, the relationship between the inclination angle of the droplet impacting on the inclined wall and the spreading is obtained, and the influence of droplets with different Weber numbers, and dry and wetted walls were analyzed, which provide a basis for the optimization of the corrugated plate separator.
Study on Effect of Sloshing Phenomenon on Water Level of Pressurizer
Authors: Jiarui Chen , Jianchang Liu , Dongyang Li , Sichao Tan
Published: October 2020

As the key equipment to control the pressure stability of the coolant system, the pressurizer plays a role in maintaining the primary system pressure in the reactor. During the operation of the sea-based reactor, the internal free liquid level of the pressurizer will fluctuate greatly with different marine cycles, causing additional acceleration in the horizontal or vertical direction, which will cause the water level measured by the differential pressure measurement method to deviate from the actual water level. It will adversely affect the judgment and control of the signal. Moreover, the fluctuating liquid level will frequently trigger the water level alarm signal, resulting in the submersion of the sprinkler tuber and the exposure of the electric heating rod, which will reduce the safety and economy of the reactor. Therefore, this research is aimed at suppressing the fluctuation range of the water level and correcting the deviation of the water level measurement so as to improve the inherent safety of the reactor. In the present study, the experimental system consists of a motion excitation drive mechanism and an optical system. The experimental system has successfully established sloshing phenomenon of the pressurizer under different forms of motion by Laser induced fluorescence (LIF) technique and the experimental results obtained are compared with numerical results. The results of the research show that the pressurizer can make significant free surface fluctuation when excitation close to the natural frequency of the pressurizer. The suppression model developed by FLUTENT can effectively reduce the fluctuation range of free liquid level. In addition, the deviation of water level measurement enlarges with the swing angle increasing. The deviation can be reduced to the allowable error range by means of angle correction.
Physical and chemical vapor deposition methods applied to all-inorganic metal halide perovskites
Authors: Bonomi Sara , Malavasi Lorenzo
Published: October 2020

This review focuses on the physical and chemical vapor deposition methods applied to the preparation of all-inorganic metal halide perovskites. Particular emphasis is devoted to the specific characteristic of the available approaches explored in the current literature for lead-based and lead-free films with also examples of the preparation of microstructure and nanostructure for applications beyond perovskite solar cells. Main characteristics, device architectures, and pros and cons of exploited vapor deposition methods are highlighted, providing a guide for future research in the field of all-inorganic perovskite growth.
Examining Multilevel Environmental Correlates of Physical Activity Among Older Adults With Multiple Sclerosis
Authors: Silveira Stephanie L. , Baird Jessica F. , Motl Robert W.
Published: October 2020

Three hundred and sixty-three older adults with multiple sclerosis completed a cross-sectional study examining hierarchical correlates of physical activity using a social cognitive theory perspective within a social ecological model (i.e., built environment, social environment, and individual social cognitive theory variables). Hierarchical linear regression analyses were conducted, wherein significant associations were noted for built environment (i.e., land-use mix diversity and aesthetics) and physical activity in Step 1 (R2 = .09). Social and built environment were significant correlates in Step 2 (R2 = .15). Finally in Step 3, individual social cognitive theory variables (i.e., self-efficacy and outcome expectations) were the only significant correlates of total physical activity (R2 = .38). Results were comparable for health-promoting physical activity; however, self-efficacy was the only significant correlate in Step 3 (R2 = .36). This study provides guidance for researchers and practitioners on relevant targets for tailoring interventions for older adults with multiple sclerosis and supports an emphasis on self-efficacy as a primary predictor of health behavior change.
Influence of Badminton Practice on Age-Related Changes in Patellar and Achilles Tendons
Authors: Bravo-Sánchez Alfredo , Abián Pablo , Sousa Filipa , Jimenez Fernando , Abián-Vicén Javier
Published: October 2020

Regular sport practice could prevent age-related changes in tendinous tissues. The purpose of the study was to investigate the effect of regular badminton practice on patellar and Achilles tendon mechanical properties in senior competitive badminton players (>35 years old) and to compare the results with physically active people matched by age. One hundred ninety-two badminton players and 193 physically active people were divided by age into four groups, between 35 and 44 (U45), between 45 and 54 (U55), between 55 and 64 (U65), and over 65 (O65) years old. A LogiqS8 transducer in elastography mode and a MyotonPRO myotonometer were used to assess patellar and Achilles mechanical properties. Achilles tendon stiffness was higher in the control group than the badminton players for the U45, U55, and O65 age groups (p < .01). Also, the elastography index was higher in the control group than the badminton players for the U45, U55, U65, and O65 age groups (p < .05). In conclusion, regular badminton practice could prevent the decline in mechanical properties of the patellar and Achilles tendons.
Bidirectional Day-to-Day Associations of Reported Sleep Duration With Accelerometer Measured Physical Activity and Sedentary Time Among Dutch Adolescents: An Observational Study
Authors: Berninger Nathalie , Knell Gregory , Gabriel Kelley Pettee , Plasqui Guy , Crutzen Rik , Ten Hoor Gill
Published: October 2020

Objectives: To examine the bidirectional association of sleep duration with proportions of time spent in physical behaviors among Dutch adolescents. Methods: Adolescents (n = 294, 11–15 years) completed sleep diaries and wore an accelerometer (ActiGraph) over 1 week. With linear mixed-effects models, the authors estimated the association of sleep categories (short, optimal, and long) with the following day’s proportion in physical behaviors. With generalized linear mixed models with binomial distribution, the authors estimated the association of physical behavior proportions on sleep categories. Physical behavior proportions were operationalized using percentages of wearing time and by applying a compositional approach. All analyses were stratified by gender accounting for differing developmental stages. Results: For males (number of observed days: 345, n = 83), short as compared with optimal sleep was associated with the following day’s proportion spent in sedentary (−2.57%, p = .03, 95% confidence interval [CI] [−4.95, −0.19]) and light-intensity activities (1.96%, p = .02, 95% CI [0.27, 3.65]), which was not significant in the compositional approach models. Among females (number of observed days: 427, n = 104), long sleep was associated with the proportions spent in moderate- to vigorous-intensity physical activity (1.69%, p < .001, 95% CI [0.75, 2.64]) and in sedentary behavior (−3.02%, p < .01, 95% CI [−5.09, −0.96]), which was replicated by the compositional approach models. None of the associations between daytime activity and sleep were significant (number of obs.: 844, n = 204). Conclusions: Results indicate partial associations between sleep and the following day’s physical behaviors, and no associations between physical behaviors and the following night’s sleep.
The Examination of Repeated Self-Mobilizations With Movement and Joint Mobilizations on Individuals With Chronic Ankle Instability
Authors: Burton Connor A. , Arthur Robert J. , Rivera Matthew J. , Powden Cameron J.
Published: October 2020

Context: Chronic ankle instability (CAI) is one of the most common chronic conditions in the world, resulting in millions of dollars contributed to the health care system. Joint mobilizations have been shown to effectively improve patient and disease-specific impairments secondary to CAI. The ability for patients to complete an effective manual therapy intervention without the need for continuous visits to a health care provider can alleviate burdens on the health care system and improve patient satisfaction. Objective: To examine the effect of clinician-applied Maitland talocrural joint mobilization and self-mobilization (Self-Mob) on dorsiflexion range of motion (DFROM), dynamic balance, strength, and perceived function in those with CAI. Design: Single-blind randomized trial. Setting: Research laboratory. Participants: A total of 18 participants (7 males and 11 females; age = 20.78 [2.02] y, height = 67.66 [3.83] cm, limb length = 87.74 [5.05] cm) with self-reported CAI participated. Interventions: The participants received 6 interventions over a 2-week period. The participants received either Maitland grade III anterior-to-posterior talocrural joint mobilizations or weight-bearing lunge Self-Mob. Each intervention consisted of four 2-minute sets, with a 1-minute rest between sets. Main Outcome Measures: The DFROM (weight-bearing lunge), dynamic balance (Y-Balance Test), isometric strength, Foot and Ankle Ability Measure Quick, Disablement of the Physically Active modified, Fear Avoidance Beliefs Questionnaire, and Tampa Scale of Kinesiophobia-11 were measured preintervention and postintervention. Results: Dynamic balance, isometric strength, and perceived function significantly improved in both groups at postintervention. The DFROM significantly improved in the Self-Mob group. Higher individual responder rates were demonstrated within the Self-Mob group compared with clinician-applied mobilizations. Conclusions: Clinician-applied mobilizations and Self-Mobs are effective interventions for improving dynamic balance, isometric strength, and perceived function. Application of Self-Mobs can effectively improve DFROM compared with joint mobilization. Self-Mobs may be an effective intervention to incorporate into a home care plan.
Individuals With Parkinson’s Disease Retain Spatiotemporal Gait Control With Music and Metronome Cues
Authors: Chawla Guneet , Hoppe Madelon , Browner Nina , Lewek Michael D.
Published: October 2020

The purpose of this study was to determine the difference in spatiotemporal gait measures induced by stepping to the beat of a metronome and to music cues of various frequencies in individuals with Parkinson’s disease. Twenty-one participants with Parkinson’s disease were instructed to time their steps to a metronome and music cues (at 85%, 100%, and 115% of overground cadence). The authors calculated cadence, cadence accuracy, and step length during each cue condition and an uncued control condition. The music and metronome cues produced comparable results in cadence manipulation, with reduced cadence accuracy noted at slower intended frequencies. Nevertheless, the induced cadence elicited a concomitant alteration in step length. The music and metronome cues produced comparable changes to gait, but suggest that temporal control is more limited at slower frequencies, presumably by the challenge of increasing the step length.
Converging Interests, Unequal Benefits? Tribal Critical Race Theory and Miami University’s Myaamia Heritage Logo
Authors: Hodler Matthew , Batts Maddox Callie
Published: October 2020

Miami University has used Native American imagery to promote itself since its founding. In 1929, Miami teams began using the racist term Redsk*ns. In 1996–1997, they changed the name to RedHawks. Despite the strengthening relationship between the university and the tribe, the racist mascot imagery remained visible in the university community. In 2017–2018, the university returned to Native American imagery by unveiling a new “Heritage Logo” to represent a commitment to restoring the Myaamia language and culture. In this paper, the authors used tribal critical race theory to analyze how the Heritage Logo represents a point of interest convergence, where symbols of the tribe signal acceptance and recognition of the Myaamia people, while institutional racism and the possessive investment of whiteness are left ignored and unaddressed.
An Exposure-Response Perspective on the Clinical Dose of Pretomanid
Authors: Nedelman Jerry R. , Salinger David H. , Subramoney Vishak , Woolson Rob , Wade Karen , Li Mengchun , Everitt Daniel , Mendel Carl M. , Spigelman Mel
Published: October 2020

Pretomanid was approved by the U.S. FDA, via the limited population pathway for antibacterial and antifungal drugs, as part of a three-drug regimen with bedaquiline and linezolid for the treatment of extensively drug-resistant and treatment-intolerant or nonresponsive multidrug-resistant tuberculosis. The recommended dose of pretomanid is 200 mg once daily with food. The objective of this work was to retrospectively evaluate this recommended dose by means of exposure-response (E-R) modeling applied to outcomes of both efficacy and safety.
Optimization of a Noncanonical Anti-infective: Interrogation of the Target Binding Pocket for a Small-Molecule Inhibitor of Escherichia coli Polysaccharide Capsule Expression
Authors: Arshad Mehreen , Beggs Grace A. , Brennan Richard G. , Seed Patrick C.
Published: October 2020

We previously identified a small-molecule inhibitor of capsule biogenesis (designated DU011) and identified its target as MprA, a MarR family transcriptional repressor of multidrug efflux pumps. Unlike other proposed MprA ligands, such as salicylate and 2,4-dinitrophenol (DNP), DU011 does not alter
Escherichia coli
antibiotic resistance and has significantly enhanced inhibition of capsule expression. We hypothesized that the potency and the unique action of DU011 are due to novel interactions with the MprA binding pocket and the conformation assumed by MprA upon binding DU011 relative to other ligands.
Pharmacokinetics and Time-Kill Study of Inhaled Antipseudomonal Bacteriophage Therapy in Mice
Authors: Chow Michael Y. T. , Chang Rachel Yoon Kyung , Li Mengyu , Wang Yuncheng , Lin Yu , Morales Sandra , McLachlan Andrew J. , Kutter Elizabeth , Li Jian , Chan Hak-Kim
Published: October 2020

Inhaled bacteriophage (phage) therapy is a potential alternative to conventional antibiotic therapy to combat multidrug-resistant (MDR)
Pseudomonas aeruginosa
infections. However, pharmacokinetics (PK) and pharmacodynamics (PD) of phages are fundamentally different from antibiotics and the lack of understanding potentially limits optimal dosing. The aim of this study was to investigate the
in vivo
PK and PD profiles of antipseudomonal phage PEV31 delivered by pulmonary route in immune-suppressed mice.
Lactic Acid Supplementation Increases Quantity and Quality of Gametocytes in Plasmodium falciparum Culture
Authors: West Rachel , Sullivan David J.
Published: October 2020

Malaria infection by
Plasmodium falciparum
continues to afflict millions of people worldwide, with transmission being dependent upon mosquito ingestion of the parasite gametocyte stage. These sexually committed stages develop from the asexual stages, yet the factors behind this transition are not completely understood. Here, we found that lactic acid increases gametocyte quantity and quality in
P. falciparum
culture. Low-passage-number NF54 parasites exposed to 8.
Antibody Neutralization of HIV-1 Crossing the Blood-Brain Barrier
Authors: Lorin Valérie , Danckaert Anne , Porrot Françoise , Schwartz Olivier , Afonso Philippe V. , Mouquet Hugo
Published: October 2020

HIV-1 can cross the blood-brain barrier (BBB) to penetrate the brain and infect target cells, causing neurocognitive disorders as a result of neuroinflammation and brain damage. The HIV-1 envelope spike gp160 is partially required for viral transcytosis across the BBB endothelium. But do antibodies developing in infected individuals and targeting the HIV-1 gp160 glycoproteins block HIV-1 transcytosis through the BBB? We addressed this issue and discovered that anti-gp160 antibodies do not block HIV-1 transport; instead, free viruses and those in complex with antibodies can transit across BBB endothelial cells. Importantly, we found that only neutralizing antibodies could inhibit posttranscytosis viral infectivity, highlighting their ability to protect susceptible brain cells from HIV-1 infection.
Cryptic or Silent? The Known Unknowns, Unknown Knowns, and Unknown Unknowns of Secondary Metabolism
Authors: Hoskisson Paul A. , Seipke Ryan F.
Published: October 2020

Microbial natural products, particularly those produced by filamentous
Actinobacteria
, underpin the majority of clinically used antibiotics. Unfortunately, only a few new antibiotic classes have been discovered since the 1970s, which has exacerbated fears of a postapocalyptic world in which antibiotics have lost their utility. Excitingly, the genome sequencing revolution painted an entirely new picture, one in which an average strain of filamentous
Actinobacteria
harbors 20 to 50 natural product biosynthetic pathways but expresses very few of these under laboratory conditions.
Introducing the Mangrove Microbiome Initiative: Identifying Microbial Research Priorities and Approaches To Better Understand, Protect, and Rehabilitate Mangrove Ecosystems
Authors: Allard Sarah M. , Costa Matthew T. , Bulseco Ashley N. , Helfer Véronique , Wilkins Laetitia G. E. , Hassenrück Christiane , Zengler Karsten , Zimmer Martin , Erazo Natalia , Mazza Rodrigues Jorge L. , Duke Norman , Melo Vânia M. M. , Vanwonterghem Inka , Junca Howard , Makonde Huxley M. , Jiménez Diego Javier , Tavares Tallita C. L. , Fusi Marco , Daffonchio Daniele , Duarte Carlos M. , Peixoto Raquel S. , Rosado Alexandre S. , Gilbert Jack A. , Bowman Jeff
Published: October 2020

Mangrove ecosystems provide important ecological benefits and ecosystem services, including carbon storage and coastline stabilization, but they also suffer great anthropogenic pressures. Microorganisms associated with mangrove sediments and the rhizosphere play key roles in this ecosystem and make essential contributions to its productivity and carbon budget. Understanding this nexus and moving from descriptive studies of microbial taxonomy to hypothesis-driven field and lab studies will facilitate a mechanistic understanding of mangrove ecosystem interaction webs and open opportunities for microorganism-mediated approaches to mangrove protection and rehabilitation.
Challenges in clinical trials for children and young people
Authors: Lagler Florian B , Hirschfeld Steven , Kindblom Jenny M
Published: October 2020

There is a well-known knowledge gap regarding the efficacy and safety of medicines in children of all ages and children are often treated with medicines off-label. Children are thus deprived of treatment based on the same quality of information that guides treatment in adults. The knowledge gap regarding efficacy and safety of medicines in children has been acknowledged by authorities and is reflected in legislation both in North America and in the European Union. Recent reports on the effects of legislation indicates that paediatric clinical trials remain a challenge.

Paediatric clinical trials are needed in the entire developmental age spectrum and are especially needed in certain therapy areas. Paediatric clinical trials have special features compared with trials in adults, and these need to be taken into account. These special features include scientific issues related to small samples and heterogeneity, the consent/assent procedure, the need for age-appropriate study information, specific outcomes and safety issues related to development and maturation. Competence in paediatric clinical trials is required in both designing, planning, co-ordinating and organising paediatric clinical trials, as well as research infrastructure and networks to increase power and disseminate information and expert advice. Strengthening of paediatric clinical research is essential to facilitate generating the data that will let children enjoy new medical advances in a similar manner as adults.
Efficacy of intravitreal AFlibercept injection For Improvement of retinal Nonperfusion In diabeTic retinopathY (AFFINITY study)
Authors: Kim Yoon Jeon , Yeo Joon Hyung , Son Gisung , Kang Hyojoo , Sung Yu Sub , Lee Joo Yong , Kim June-Gone , Yoon Young Hee
Published: October 2020

Introduction

To evaluate the effects of intravitreal aflibercept injection on retinal nonperfusion in patients with diabetic retinopathy (DR) using ultrawide field (UWF) fluorescein angiography (FA).

Research design and methods

Thirty-eight eyes of 38 consecutive patients with DR and substantial retinal nonperfusion (nonperfusion index (NPI): nonperfused/total gradable area >0.2) without macular edema were included in this prospective case series. Monthly injections of 2 mg aflibercept were given for 6 months. UWF-fundus photography and UWF-FA images were acquired at baseline, 6 months, and 12 months and evaluated by 2 masked, independent graders for the extent of retinal nonperfusion and vascular leakage. Twenty untreated fellow eyes were analyzed as controls.

Results

Inter-grader agreement was strong (r=0.875) for NPI measurements. NPI was 0.46±0.10 at baseline; NPI was decreased to 0.43±0.08 (p=0.015) after 6 monthly injections of aflibercept and then slightly increased to 0.44±0.09 (p=0.123) after 6 months of observation. Vascular leakage also significantly decreased by 21.0% at 6 months (p=0.010). Untreated fellow eyes did not show significant changes in NPI and vascular leakage during follow-up. Reduction in retinal nonperfusion was associated with severe nonproliferative diabetic retinopathy (NPDR) (vs PDR, OR 19.119, p=0.025) and higher leakage index (per 0.1, OR 15.152, p=0.020).

Conclusions

Intensive aflibercept treatment was effective in reducing retinal capillary nonperfusion in patients with DR without macular edema. Severe NPDR and profound vascular leakage were significantly associated with retinal reperfusion after aflibercept treatment.

Trial registration number

NCT03006081.
Exposure to traffic-related particle matter and effects on lung function and potential interactions in a cross-sectional analysis of a cohort study in west Sweden
Authors: Carlsen Hanne Krage , Nyberg Fredrik , Torén Kjell , Segersson David , Olin Anna-Carin
Published: October 2020

Objectives

To investigate the long-term effects of source-specific particle matter (PM) on lung function, effects of Surfactant Protein A (SP-A) and glutathione S-transferase (GST) genes GSTP1 and GSTT1 gene variants and effect modification by single-nucleotide polymorphism (SNP) genotype.

Design

Cohort study with address-based annual PM exposure assigned from annual estimates of size (PM10, PM2.5 and PMBC) and source-specific (traffic, industry, marine traffic and wood burning) dispersion modelling.

Setting

Gothenburg, Sweden.

Participants

The ADult-Onset asthma and NItric oXide Study had 6685 participants recruited from the general population, of which 5216 (78%) were included in the current study with information on all variables of interest. Mean age at the time of enrolment was 51.4 years (range 24–76) and 2427 (46.5%) were men.

Primary and secondary outcome measures

The primary outcome was forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). Secondary outcome measures were effects and gene–environment interactions of SP-A and GSTT1 and GSTP1 genotypes.

Results

Exposure to traffic-related PM10 and PM2.5 was associated with decreases in percent-predicted (% predicted) FEV1 by −0.48% (95% CI −0.89% to −0.07%) and −0.47% (95% CI −0.88% to −0.07%) per IQR 3.05 and 2.47 µg/m3, respectively, and with decreases in % predicted FVC by −0.46% (95% CI −0.83% to −0.08%) and −0.47% (95% CI −0.83% to −0.10%). Total and traffic-related PMBC was strongly associated with both FEV1 and FVC by −0.53 (95% CI −0.94 to −0.13%) and −0.43% (95% CI −0.77 to −0.09%) per IQR, respectively, for FVC, and similarly for FEV1. Minor allele carrier status for two GSTP1 SNPs and the GSTT1 null genotype were associated with decreases in % predicted lung function. Three SP-A SNPs showed effect modification with exposure to PM2.5 from industry and marine traffic.

Conclusions

PM exposure, specifically traffic related, was associated with FVC and FEV1 reductions and not modified by genotype. Genetic effect modification was suggested for industry and marine traffic PM2.5.
Group-based intervention to improve developmental status among children age 6–18 months in rural Shanxi province, China: a study protocol for a cluster randomised controlled trial
Authors: Xu Mengxue , Liu Aihua , Zhao Chunxia , Fang Hai , Huang Xiaona , Berman Stephen , Guan Hongyan
Published: October 2020

Introduction

Early childhood development (ECD) is a critical component for building the foundation of future physical and emotional health and subsequent academic success. The quality of the home environment to promote development is an important factor in ECD. Since large rural–urban disparities in the home environment exist in China, there is a critical need to develop and evaluate interventions to promote ECD in rural areas. Individual center-based or home-based interventions dominate the current ECD programmes in rural China. However, group-based interventions offer potential advantages in terms of both effectiveness and cost. Thus, we aim to: (1) evaluate the effectiveness of an integrated group-based intervention, the Care Group Intervention, in enhancing ECD among children age 6–18 months and (2) conduct a cost-effectiveness analysis.

Methods and analysis

The Care Group Intervention uses a cluster (by township) randomised controlled trial conducted in Fenxi county, Shanxi province, China, from July 2019, for 1 year. The intervention focuses on five key components of nurturing care including good health, adequate nutrition, responsive caregiving, security and safety, and opportunities for early learning. The intervention comprises small groups of 3–10 children within a certain age range and their primary caregivers that are led by well-trained local facilitators. Outcomes includes infants’ developmental quotient (Bayley Scales of Infant Development III, Ages & Stages Questionnaire: Social–Emotional, second edition); anaemia (HemoCue Hb 301+); nurturing environment (Infant/Toddler Home Observation for Measurement of the Environment), parent-child interaction (Teaching Scale) and caregiver depression (Center for Epidemiological Studies Depression). Cost data are collected throughout the entire study to carry out a cost-effectiveness analysis.

Ethics and dissemination

This study was approved by the Ethical Committee of Capital Institute of Pediatrics, Beijing, China on 10 July 2018 (SHERLL2018014). Findings and results from this project will be disseminated via publications and presentations.

Trial registration number

Chinese Clinical Trials Registry: ChiCTR1900022894. Registered on 30 April 2019.