bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the Very High Cycle Fatigue (VHCF) Behavior of Austenitic Stainless Steels and Their Welds for Reactor Internals at Ambient Temperature and 300°C
Authors: Daniel T. , Smaga M. , Beck T. , Schopf T. , Stumpfrock L. , Weihe S. , Rudolph J. 
Published: December 2020

Abstract
The fatigue assessment of safety relevant components is of importance for ageing management with regard to safety and reliability of nuclear power plants.
For reactor internals, austenitic stainless steels are often used due to their excellent mechanical and technological properties as well as their corrosion resistance. During operation the material is subject to loadings in the Low Cycle Fatigue (LCF) regime due to start up and shut down procedures as well as high frequency loadings in the Very High Cycle Fatigue (VHCF) regime induced e.g. by stresses due to fast cyclic thermal fluctuations triggered by fluid dynamic processes. While the LCF behavior of austenitic steels is already well investigated the fatigue behavior in the VHCF regime has not been characterized in detail so far. Accordingly, the fatigue curves in the applicable international design codes have been extended by extrapolation to the range of highest load cycles (Fig. 1).
The aim of the cooperative project of the Institute of Materials Science and Engineering (WKK), Materials Testing Institute (MPA) Stuttgart and Framatome GmbH, Germany is to create a comprehensive database up to the highest load cycles N = 2·109 for austenitic stainless steels. For this fatigue tests on metastable austenitic steel AISI 347 / 1.4550 / X6CrNiNb1810 as well as austenitic welds (Fox SAS 2-A) were performed at an ultrasonic testing system at a test frequency of 20 000 Hz to realize acceptable testing times. In addition, an induction generator was implemented in the test system to investigate the influence of operation relevant temperature of 300 °C on the fatigue behavior. The ultrasonic testing system works under displacement control. Therefore, for reliable statements on fatigue life according NUREG/CR-6909 and using of S-N-curve (total-strain amplitude vs. cycle to failure) a fictitious-elastic and elastically-plastic numerical material model was used for calculation of total-strain amplitudes based on experimental data. The results shown, that at ambient temperature (AT) and 300 °C no specimen failure occurred in the VHCF regime for the base material as well as for the welds. Consequently, for these materials a real endurance limit exists.
Additionally, in a continuative test a specimen with a pre-autoclaving period in high temperature water (HTW) of 2500 hours was tested in air at a total strain amplitude of 0.1 % in the VHCF-regime up to number of cycle N = 109 using an ultrasonic fatigue testing system. The chemical composition of the HTW for the pre-autoclaving period is comparable to near operation conditions. Afterwards by using of scanning electron microscope no defects or cracks were detected in the oxide layer.
Stress Intensity Factor and Crack Opening Area of Circumferentially-Cracked Pipe Under Torsion Moment
Authors: Huang Yifan , Duan Xinjian 
Published: December 2020

Abstract
The deterministic leak-before-break (LBB) analysis and probabilistic fracture mechanics (PFM) assessment are two primary approaches for demonstrating extremely low probability of rupture of pressurized piping in the nuclear energy industry. Both stress intensity factor (SIF) and crack opening area (COA) are key components to the LBB and PFM assessments. Most of the studies and engineering practices focus on the SIF and COA due to axial tension, bending moment and internal pressure while limited investigations target on these parameters caused by torsion moment.
The objective of this study is to perform three-dimensional finite element analyses (3D FEA) to determine both SIF and COA for through-wall circumferential cracks in the pipe under bending or torsion moment. A range of normalized crack lengths (i.e. θ/π = 1/18 to 4/9) and three pipe radius over thickness ratios (i.e. Rm/t = 5, 10 and 25) are considered. Empirical solutions of the SIF for torsion loading as functions of crack geometry are developed. Comparisons for SIF regarding combined bending and torsion moments evaluated using code-specified solutions are presented. Finally, the COAs regarding the two loading modes are discussed. Such study is expected to be useful for both deterministic LBB analysis and PFM assessment of pressurized pipes.
Method for Comparison of Different Material Types in Environmental Fatigue Screening
Authors: Gray Mark A. , Oakman Jamie L. , Walker Adam P. 
Published: December 2020

Abstract
Requirements for plant license renewal require the evaluation and management of time limited aging analyses for the period of extended operation. These include metal fatigue analyses, with additional consideration for the effects of the reactor water environment. Current license renewal requirements for evaluation of time limited aging analyses for fatigue have extended environmentally assisted fatigue (EAF) considerations to additional locations beyond the originally prescribed NUREG/CR-6260 locations. These requirements have resulted in implementation of a screening process to identify locations that are potentially more limiting for further evaluation of EAF. The screening process includes comparisons of fatigue locations within common bases, including consideration of applicable system transients, rigor of analysis methods, and material types. To date, the United States Nuclear Regulatory Commission has only accepted EAF screening evaluation results based on comparisons within similar material types. However, there are conditions under which a comparison of locations with different material types is valid. This paper presents a basis to compare locations having different material types, to potentially reduce the number of leading (“sentinel”) locations in EAF screening evaluations. The methodology is described through a systematic approach and basis to determine when locations are more limiting with respect to EAF when different material types are compared.
Prediction of Collapse Load Reduction due to Non-Aligned Multiple Flaws
Authors: Iwamatsu Fuminori , Miyazaki Katsumasa , Saito Koichi 
Published: December 2020

Abstract
Fitness-for-Service (FFS) codes, such as ASME Boiler and Pressure Vessels Code, Section XI, have flaw characterization rules for evaluation of structural integrity. Since stress corrosion cracking (SCC) and thermal fatigue frequently cause multiple flaws, FFS codes should have proximity rules as a part of flaw characterization rules. The flaw characterization rules should consider fracture modes, such as brittle fracture, ductile fracture, and plastic collapse. Those in the current codes are not divided by the fracture modes. Especially, application of the current proximity rules to plastic collapse of non-aligned multiple flaws should be validated because there are few studies for this issue. Thus, fracture tests of flat plates with through-wall flaws and finite element analysis (FEA) were conducted for predicting collapse loads due to plastic collapse. A series of the fracture tests of flat plates with non-aligned two flaws has been conducted, and a trend between the load reduction and the flaw locations was shown from the results. This trend shows that the defined net-section for non-aligned multiple flaw dominate the collapse load. For the validation the trend shown by the fracture tests, FEA was performed for predicting the measured collapse load. Equivalent plastic strain around a flaw tip dominates a collapse behavior, and an equivalent plastic strain at collapse called as fracture strain was determined for FEA. The collapse loads predicted by the fracture strain are correspond with the test results for any flaw locations. FEA conditions can interpolate and cover a wide range of flaw locations conducted by the tests. The load ratios which represent effect of flaw interaction on a collapse load were estimated by parametric FEA. The ratios were mapped to investigate the trend of the effect on a collapse load. The mapped results show that the load ratio depends on a shorter flaw length of two flaws. This trend shown by the analysis results is corresponds with the fracture test results. These results are fundamental idea to make a flaw characterization rule in the FFS codes, such as ASME BPVC Section XI, for ductile fracture evaluation.
Light harvesting in oxygenic photosynthesis: Structural biology meets spectroscopy
Authors: Croce Roberta , van Amerongen Herbert 
Published: December 2020

Architectures for light harvesting
Conversion of light energy into chemical energy ultimately drives most biochemistry on earth. Photosynthetic organisms use diverse chemical and biological structures to harvest light in different environmental contexts. Croce and van Amerongen synthesized recent structural and spectroscopic work on photosystem complexes from oxygenic photosynthetic organisms. To best capture light, photosystems contain accessory light-harvesting complexes harboring complex networks of pigments that shuttle electronic excitations toward the core complex, which contains the reaction center. The arrangement of pigments and their connectivity, as seen in high-resolution x-ray and cryo–electron microscopy structures, inform our understanding of energy transfer rates derived from spectroscopic measurements and vice versa. The model that emerges is one of many parallel and unconnected pathways for energy transfer into the reaction center from the exterior light-harvesting complexes.

Science
, this issue p.
eaay2058
SGLT2 inhibitors in patients with type 2 diabetes with non-alcoholic fatty liver diseases: an umbrella review of systematic reviews
Authors: Shao Shih-Chieh , Kuo Liang-Tseng , Chien Rong-Nan , Hung Ming-Jui , Lai Edward Chia-Cheng 
Published: December 2020

IntroductionSodium glucose co-transporter 2 (SGLT2) inhibitors have been reported to benefit liver functions in patients with type 2 diabetes (T2D) with non-alcoholic fatty liver disease (NAFLD). The aim of this study is to critically appraise existing systematic reviews in order to consolidate evidence associating the use of SGLT2 inhibitors with beneficial hepatic results for patients with T2D with NAFLD.MethodsThis umbrella review searched relevant published systematic reviews of clinical trials from PubMed and Embase between inception and September 16, 2020. Two independent investigators appraised study quality using AMSTAR2 (Assessment of Multiple Systematic Reviews 2). The hepatic effects from SGLT2 inhibitors were summarized based on liver enzymes, liver fat, liver histology, liver cirrhosis and liver cancer.ResultsOf 25 screened potential systematic reviews, we ultimately included 7 in this study. However, none of them could be rated as being of high methodological quality. Five systematic reviews indicated that SGLT2 inhibitors could effectively decrease liver fat and liver parameters of alanine aminotransferase and gamma-glutamyl transferase in patients with NAFLD. Two systematic reviews indicated that SGLT2 inhibitors could reduce hepatosteatosis, as supported by biopsy-proven evidence of improvement from a small clinical trial, but no evidence of liver fibrosis improvement was found.ConclusionsThere is some association between SGLT2 inhibitor use and observed benefits to liver functions in patients with T2D with NAFLD, although the quality of current systematic reviews remains relatively low. Further evaluation of long-term liver outcomes with SGLT2 inhibitors in cases of liver cirrhosis and liver cancer is warranted.
Is hackathon in oncology a plausible way to foster innovation? An experiential narrative account of conducting Hacking Cancer
Authors: Lewis Shirley , Rao Chythra R , Shenoy Padmaja Ananth , Salins Naveen , Viveganandan Rangan , Shanbhag Arun , Mukhopadhyay Chiranjay , Prabhu Krishnananda , Rao Sharath K 
Published: December 2020

Background
Hackathons are a popular trend in the technology domain and is considered a powerful tool to spur creativity and innovation. In a health hackathon, an interdisciplinary team of health, technology and management experts work collaboratively to solve a common problem. Health hackathon can be one of the quickest means to derive technology or process-based solutions to the challenges faced by clinicians.

Methods
A 2-day hackathon: Hacking Cancer was conducted at a tertiary cancer centre in India to develop quick, cost-effective solutions in cancer care. Twelve oncology-related problem statements were explored. Undergraduate and postgraduate students of health and dental sciences, pharmacy, nursing, engineering and business management were the participants.

Outcomes
One hundred and fifty-seven participants expressed interest, and 90 participated in the event. The participants did a time-bound exploration of 12 challenges in oncology elucidated problem statements. The oncology specialists mentored the participants during the hackathon. Seventeen teams presented their solutions. Judges reviewed the solutions and scored the teams based on feasibility, relevance and applicability. The top-scoring three projects were acute lymphoblastic leukaemia (ALL) better-improving adherence to treatment in ALL patients, Donate Life—application for voluntary blood donation and Lumiflex—a novel illuminated flexible abdominal retractor. They received seed funding to develop prototypes and implement their ideas.

Conclusion
Hacking Cancer was an effective way of developing quick, cost-effective solutions to the common problems faced in cancer care. The pool of local participants developed solutions that were relevant and applicable to the practice setting. This one was the first oncology themed hackathon in the country.
Impact of Plasma Potassium Normalization on Short‐Term Mortality in Patients With Hypertension and Hyperkalemia
Authors: Krogager Maria Lukács , Søgaard Peter , Torp‐Pedersen Christian , Bøggild Henrik , Gislason Gunnar , Kragholm Kristian 
Published: December 2020

Background
Hyperkalemia can be harmful, but the effect of correcting hyperkalemia is sparsely studied. We used nationwide data to examine hyperkalemia follow‐up in patients with hypertension.

Methods and Results

We identified 7620 patients with hypertension, who had the first plasma potassium measurement ≥4.7 mmol/L (hyperkalemia) within 100 days of combination antihypertensive therapy initiation. A second potassium was measured 6 to 100 days after the episode of hyperkalemia. All‐cause mortality within 90 days of the second potassium measurement was assessed using Cox regression. Mortality was examined for 8 predefined potassium intervals derived from the second measurement: 2.2 to 2.9 mmol/L (n=37), 3.0 to 3.4 mmol/L (n=184), 3.5 to 3.7 mmol/L (n=325), 3.8 to 4.0 mmol/L (n=791), 4.1 to 4.6 mmol/L (n=3533, reference), 4.7 to 5.0 mmol/L (n=1786), 5.1 to 5.5 mmol/L (n=720), and 5.6 to 7.8 mmol/L (n=244). Ninety‐day mortality in the 8 strata was 37.8%, 21.2%, 14.5%, 9.6%, 6.3%, 6.2%, 10.0%, and 16.4%, respectively. The multivariable analysis showed that patients with concentrations >5.5 mmol/L after an episode of hyperkalemia had increased mortality risk compared with the reference (hazard ratio [HR], 2.27; 95% CI, 1.60–3.20;
P
<0.001). Potassium intervals 3.5 to 3.7 mmol/L and 3.8 to 4.0 mmol/L were also associated with increased risk of death (HR, 1.71; 95% CI, 1.23–2.37;
P
<0.001; HR, 1.36; 95% CI, 1.04–1.76;
P
<0.001, respectively) compared with the reference group. We observed a trend toward increased risk of death within the interval 5.1 to 5.5 mmol/L (HR, 1.29; 95% CI, 0.98–1.69). Potassium concentrations <4.1 mmol/L and >5.0 mmol/L were associated with increased risk of cardiovascular death.

Conclusions
Overcorrection of hyperkalemia to levels <4.1 mmol/L was frequent and associated with increased all‐cause and cardiovascular mortality. Potassium concentrations >5.5 mmol/L were also associated with an increased all‐cause and cardiovascular mortality.
Baroreflex Sensitivity in Patients With Atrial Fibrillation
Authors: Miyoshi Miho , Kondo Hidekazu , Ishii Yumi , Shinohara Tetsuji , Yonezu Keisuke , Harada Taisuke , Sato Hiroki , Yano Yudai , Yoshimura Seiichiro , Abe Ichitaro , Shuto Takashi , Akioka Hidefumi , Teshima Yasushi , Wada Tomoyuki , Yufu Kunio , Nakagawa Mikiko , Anai Hirofumi , Miyamoto Shinji , Takahashi Naohiko 
Published: December 2020

Background
It has been reported that atrial fibrillation (AF) may contribute to impairment of baroreflex sensitivity (BRS). However, the difference of BRS between patients with persistent AF (PeAF) and those with paroxysmal AF (PAF) is unknown. We tested the hypothesis that patients with PeAF have a more impaired BRS compared with those with PAF.

Methods and Results

From October 2015 onwards, a total of 67 patients (14 women [20.9%]; mean age 65.2±10.1 years) with PAF (n=46, 68.7%) and PeAF (n=21, 31.3%), who underwent catheter ablation, were prospectively enrolled. The baseline BRS was evaluated during sinus rhythm. The baseline BRS in patients with PeAF was significantly lower than those with PAF (2.97 [0.52–6.62] ms/mm Hg versus 4.70 [2.36–8.37] ms/mm Hg,
P
=0.047). The BRS was significantly depressed after catheter ablation in all the patients (4.66 [1.80–7.37] ms/mm Hg versus 0.55 [−0.15 to 1.22] ms/mm Hg,
P
<0.001). However, the depression of BRS because of catheter ablation appeared attenuated in patients with PeAF when compared with those with PAF. The number of patients who did not show depression of BRS was significantly greater, that is, patients with PeAF (3/12, 25%) than those with PAF (0/46, 0%,
P
<0.01).

Conclusions
Our findings demonstrated that the baseline BRS was more depressed in patients with PeAF compared with PAF. Catheter ablation depressed BRS irrespective of the type of AF, with a greater effect in patients with PAF than PeAF.
Statin Use for Atherosclerotic Cardiovascular Disease Prevention Among Sexual Minority Adults
Authors: Guo Yi , Wheldon Christopher W. , Shao Hui , Pepine Carl J. , Handberg Eileen M. , Shenkman Elizabeth A. , Bian Jiang 
Published: December 2020

Background
Sexual minority, or lesbian, gay, and bisexual (LGB), individuals are at increased risk for cardiovascular disease attributable to elevated rates of health risk factors. However, although there is clear evidence that statin use can prevent cardiovscular disease in certain adult populations, no studies have examined how statins are being used among the LGB population. This study aimed to examine the prevalence and predictors of statin use among LGB and non‐LGB individuals using Facebook‐delivered online surveys.

Methods and Results

We conducted a cross‐sectional online survey about statin use in adults ≥40 years of age between September and December 2019 using Facebook advertising (n=1531). We calculated the prevalence of statin use by age, sexual orientation, and statin benefit populations. We used multivariable logistic regression to examine whether statin use differed by sexual orientation, adjusting for covariates. We observed a significantly lower rate of statin use in the LGB versus non‐LGB respondents (20.8% versus 43.8%;
P
<0.001) in the primary prevention population. However, the prevalence of statin use was not statistically different in the LGB versus non‐LGB respondents in the secondary prevention population. Adjusting for the covariates, the LGB participants were less likely to use statins than the non‐LGB respondents in the primary prevention population (odds ratio, 0.37; 95% CI, 0.19–0.70).

Conclusions
Our results are the first to emphasize the urgent need for tailored, evidence‐based cardiovascular disease prevention programs that aim to promote statin use, and thus healthy aging, in the LGB population.
A review of COVID-19-related thrombosis and anticoagulation strategies specific to the Asian population
Authors: Poh Kai Chin , Tay Victoria Yu Jia , Lin Sarah Huixin , Chee Huei Leng , Thangavelautham Suhitharan 
Published: December 2020

Abstract
The coronavirus disease 2019 (COVID-19) pandemic has placed an immense burden on healthcare systems worldwide. There is intensive research targeted at better understanding of the virus pathogenicity, development of effective treatment strategies and vaccines against COVID-19. It is increasingly being recognised that the pathogenicity of COVID-19 extends beyond the respiratory system. In severe cases, there can be widespread activation of the immune system, vascular injury and a resultant pro-thrombotic state. Severe COVID-19 is widely regarded as a risk factor for venous thromboembolism. Interim European and American guidelines have been created to guide anticoagulation strategies in COVID-19 patients. However, it is unclear if these guidelines can be extrapolated directly to Asians, in whom there are differences in the baseline risk of thrombosis and bleeding. Our review article aimed to summarise the current understanding of arteriovenous thromboembolic complications in COVID-19 and discuss management strategies for prevention and treatment of thrombotic events in Asian COVID-19 patients.
Minimum Snow/Ice Extent over the Northern Circumpolar Landmass in 2000–19: How Much Snow Survives the Summer Melt?
Authors: Trishchenko Alexander P. , Ungureanu Calin 
Published: December 2020

AbstractA novel satellite image processing technique developed at the Canada Centre for Remote Sensing has been utilized to produce annual time series of the minimum snow/ice (MSI) extent over the northern circumpolar landmass area (9,000 km × 9,000 km) for 2000–19. The information has been derived from the Moderate Resolution Imaging Spectroradiometer 10-day clear-sky composites generated at 250-m spatial resolution over the April–September period. Derived interannual variations agree very well with the warm-season average surface air temperatures from the European reanalysis (ERA5). The region-average correlation coefficient is −0.78. The total MSI extent demonstrated a statistically significant declining trend equal to −1,477 km2 yr−1. Results have been compared with data from the Randolph Glacier Inventory (RGI 6.0). The comparison points to a significant contribution of minimum seasonal snow cover relative to RGI glacierized areas. Quantitative estimates obtained for the first time showed that the region-average snow extent that survives the summer melt and resides outside of RGI area can be as high as 15% (or 53 × 103 km2) while in the northern Canadian Arctic it can reach 41% (or 43 × 103 km2). The derived MSI time series data can be recommended to the glacier and land-cover scientific community as a source of validation data and annual updates of snow and ice maps over the northern circumpolar landmass.