bluuebunny/crossref_metadata_2025 huggingface dataset:
Case Study: Resumption of Eumenorrhea in Parallel With High Training Load After 4 Years of Menstrual Dysfunction: A 5-Year Follow-Up of an Elite Female Cyclist
Authors: Areta José L.
Published: February 2020

The female athlete triad is a condition where low energy availability is typically observed together with menstrual dysfunction and/or low bone mineral density. How this condition affects maximal work capacity in endurance athletes is not clear, and the recovery time course of menses with increased energy availability with concomitant high training load is unknown. This case study of an amenorrheic elite road cyclist reports resumption of normal menstrual function after weight gain during a 5-year period (2014–2019), while engaged in high training load and competition. The athlete ( 3.54 L/min, 64 ml·min−1·kg−1, aerobic peak power output 300 W, 5.4 W/kg) reported amenorrhea (2013–2015) and oligomenorrhea (2015–2018). Training load increased from 2014 to 2019 (584–818 hr/year and 26,707–41,945 training stress score/year). Regular menses (every 23–35 days) resumed in June 2018, ∼5–6 months after a weight gain episode. During the period of menstrual dysfunction, body mass was 51.3 ± 2.25 kg (mean ± 95% confidence limit) and fat percentage was 19% (dual-energy X-ray absorptiometry, 2016), and after weight gain, body mass was 56.8 ± 2.63 kg and fat percentage was 25% (dual-energy X-ray absorptiometry, 2019). Crank-based power meter data showed absolute mean maximal power (in watts) improvement over the 5 s to 4 hr range through the 2014–2019 period, while relative mean maximal power (in watts per kilogram) likely peaked in the 2015–2016 season for 5 min, 20 min, and 30 min, but remained mostly unchanged across seasons. Results suggest that (a) the best relative power output associated with aerobic capacity (5 min to 1 hr) can be achieved during menstrual dysfunction, (b) high performance achieved despite an increase in body mass, and (c) resumption of menses is achievable while maintaining high training loads when coupled with high energy availability.
Child Care Setting and Its Association With Policies and Practices That Promote Physical Activity and Physical Literacy in the Early Years in British Columbia
Authors: McConnell-Nzunga Jennifer , Weatherson Katie A. , Masse Louise , Carson Valerie , Faulkner Guy , Lau Erica , McKay Heather , Temple Viviene , Wolfenden Luke , Naylor Patti J.
Published: February 2020

Background: Physical activity (PA) is critical to early child development, and child care is a key setting for promotion. The authors investigated differences in daily PA and sedentary behavior practices as well as physical environments between family child care (FCC) and group child care (GCC) settings for children aged 3–5 years in Canada. Methods: Group child care (n = 581) and FCC (n = 357) managers completed surveys assessing the implementation of PA promoting practices and description of their environments. Crosstabulation and chi-square tests of association were used to examine differences between GCC and FCC. Results: The prevalence of facilities implementing 120 minutes of active play (odds ratio [OR] 2.23; 95% confidence interval [CI], 1.58–3.15), <30 minutes on screens (OR 1.35; 95% CI, 1.02–1.80), and 60-minute outdoors daily (OR 1.99; 95% CI, 1.4–2.9) was more likely in FCC compared with GCC. However, implementation of fundamental movement skill activities (OR 1.40; 95% CI, 1.01–1.92), breaking up prolonged sitting (OR 1.86; 95% CI, 1.36–2.5), and outdoor space for large group running games (OR 1.74; 95% CI, 1.07–2.83) were more likely in GCC. Conclusions: Child care setting was associated with daily PA and sedentary practices and outdoor space for PA. Interventions to support PA in child care should be tailored to different settings and the facilitators explored.
The Temporal Ordering of Motivation and Self-Control: A Cross-Lagged Effects Model
Authors: Jordalen Gro , Lemyre Pierre-Nicolas , Durand-Bush Natalie , Ivarsson Andreas
Published: February 2020

Mechanisms leading to cognitive energy depletion in performance settings such as high-level sports highlight likely associations between individuals’ self-control capacity and their motivation. Investigating the temporal ordering of these concepts combining self-determination theory and psychosocial self-control theories, the authors hypothesized that athletes’ self-control capacity would be more influenced by their motivation than vice versa and that autonomous and controlled types of motivation would predict self-control capacity positively and negatively, respectively. High-level winter-sport athletes from Norwegian elite sport colleges (N = 321; 16–20 years) consented to participate. Using Bayesian structural equation modeling and 3-wave analyses, findings revealed credible self-control → motivation → self-control cross-lagged effects. Athletes’ trait self-control especially initiated the temporal ordering of the least controlled types of motivation (i.e., intrinsic, integrated, and amotivation). Findings indicate that practicing self-control competencies and promoting athletes’ autonomous types of motivation are important components in the development toward the elite level. These components will help athletes maintain their persistent goal striving by increasing the value and inherent satisfaction of the development process, avoiding the debilitating effects of self-control depletion and exhaustion.
Therapeutic Elastic Tapes Applied in Different Directions Over the Triceps Surae Do Not Modulate Reflex Excitability of the Soleus Muscle
Authors: Magalhães Igor E.J. , Mezzarane Rinaldo A. , Carregaro Rodrigo L.
Published: February 2020

Context: Elastic taping has been widely used for either to facilitate or to inhibit muscle contraction. The efficacy of elastic taping is allegedly ascribed to physiological mechanisms related to subcutaneous tissue and muscle stimulation as a result of tape tension and direction. However, the underlying mechanisms that support the use of elastic taping are still unclear. Objective: To investigate changes in electrophysiological responses after 48 hours of tape application in different directions on the calf muscles of healthy individuals. Design: Within-subjects design. Setting: Research laboratory. Participants: Twenty-seven physically active males (age 18.0 [4.2] y, height 1.65 [0.07] m, body mass 62.3 [10.3] kg) participated. Interventions: Soleus H-reflex responses were evoked through stimulation of the tibial posterior nerve with 2- to 4-second interval between stimuli (32 sweeps) for each condition (baseline: without tape; facilitation: tape applied from muscle origin to insertion; inhibition: tape applied from muscle insertion to origin). Main Outcome Measures: The H-reflex amplitude values were normalized by the maximal direct response (Mmax). Parameters were estimated from a sigmoidal fit of the H-reflex recruitment curve (ascending limb). Results: No significant differences were found for the parameters derived from the recruitment curve of the H-reflex among the conditions (P > .05). Conclusions: The authors’ findings showed that, irrespective of the direction of tape application, the elastic tape applied over the triceps surae does not generate any significant alteration on the excitability of the reflex pathway for different subpopulations of motor units. The authors therefore suggest a re-examination of the current recommendations on taping direction in clinical and sports activities.
A Comparison of 6 Weeks of Aquatic Exercise and Kinesio Taping in Patients With Chronic Nonspecific Low Back Pain
Authors: Alikhajeh Yaser , Barabadi Elyas , Mohammad Rahimi Gholam Rasul
Published: February 2020

Context: In many societies, although chronic low back pain (LBP) is a significant problem, there is no consensus on the optimal therapeutic intervention. Objective: To compare the impact of aquatic exercise (AE) and kinesio taping (KT) on the pain intensity and functional incapacity in women with chronic nonspecific LBP. Design: Randomized controlled trial. Setting: Outpatient clinic. Participants: Thirty-six women with chronic nonspecific LBP (mean [SD]: age = 50.69 [4.187] y) participated. Interventions: Participants randomly assigned to AE (n = 12), KT (n = 12), and nontreatment control (n = 12) groups for 6 weeks. Main Outcome Measures: Pain intensity and functional disability were evaluated at baseline and the end of the intervention. Results: Pain intensity decreased more in the AE group than in the KT group (5.9–0.5 cm [91.6% decrease] vs 5.7–2.4 cm [58.1% decrease], respectively; P < .001 for both after Bonferroni post hoc test); the values decreased more in the 2 treatment groups than in the control group (P < .001 for between-group comparisons). Disability decreased more in the AE group (43.2%–18.8% [55.6% decrease]) than the KT group (37.8%–19.3% [48.3% decrease]) (P < .001 for both comparisons), but increased in the control group (38.7%–41.2% [6.5% increase]; P = .045). Conclusion: These results suggest AE and KT treatment methods provide pain intensity and disability improvements in women with chronic nonspecific LBP. Nevertheless, AE was more effective than KT.
Experimental demonstration of acoustic semimetal with topologically charged nodal surface
Authors: Xiao Meng , Ye Liping , Qiu Chunyin , He Hailong , Liu Zhengyou , Fan Shanhui
Published: February 2020

This work introduces the concept of charged nodal surface, enriching the family of topological charged objects in momentum space.
Capillary-driven desalination in a synthetic mangrove
Authors: Wang Yunkun , Lee Jongho , Werber Jay R. , Elimelech Menachem
Published: February 2020

Large negative pressures (<−338 bar) generated by evaporation from nanopores allow for passive desalination of hypersaline water.
Offshore wind: An opportunity for cost-competitive decarbonization of China’s energy economy
Authors: Sherman Peter , Chen Xinyu , McElroy Michael
Published: February 2020

China can use the latest offshore wind technologies to cost-competitively supply a notable portion of its energy demand.
The hidden costs of dietary restriction: Implications for its evolutionary and mechanistic origins
Authors: McCracken Andrew W. , Adams Gracie , Hartshorne Laura , Tatar Marc , Simons Mirre J. P.
Published: February 2020

Dietary restriction leads to unexpected mortality increases when nutrient conditions improve, questioning evolutionary theory.
Evaluating the mineral commodity supply risk of the U.S. manufacturing sector
Authors: Nassar Nedal T. , Brainard Jamie , Gulley Andrew , Manley Ross , Matos Grecia , Lederer Graham , Bird Laurence R. , Pineault David , Alonso Elisa , Gambogi Joseph , Fortier Steven M.
Published: February 2020

Supply disruptions of imported mineral commodities pose significant risk to U.S. manufacturers of emerging technologies.
Discovery of a picomolar potency pharmacological corrector of the mutant CFTR chloride channel
Authors: Pedemonte Nicoletta , Bertozzi Fabio , Caci Emanuela , Sorana Federico , Di Fruscia Paolo , Tomati Valeria , Ferrera Loretta , Rodríguez-Gimeno Alejandra , Berti Francesco , Pesce Emanuela , Sondo Elvira , Gianotti Ambra , Scudieri Paolo , Bandiera Tiziano , Galietta Luis J. V.
Published: February 2020

We identified a small molecule that, at picomolar concentrations, rescues mutant CFTR chloride channel from protein degradation.
Singlet-filtered NMR spectroscopy
Authors: Mamone Salvatore , Rezaei-Ghaleh Nasrollah , Opazo Felipe , Griesinger Christian , Glöggler Stefan
Published: February 2020

We introduce an NMR scheme to selectively investigate peptides or proteins and metabolites in the brain via singlet states.
Egocentric boundary vector tuning of the retrosplenial cortex
Authors: Alexander Andrew S. , Carstensen Lucas C. , Hinman James R. , Raudies Florian , Chapman G. William , Hasselmo Michael E.
Published: February 2020

Retrosplenial cortex neurons encode the positions of environmental boundaries in coordinates relative to the animal itself.
Kinetic pathways of ionic transport in fast-charging lithium titanate
Authors: Zhang Wei , Seo Dong-Hwa , Chen Tina , Wu Lijun , Topsakal Mehmet , Zhu Yimei , Lu Deyu , Ceder Gerbrand , Wang Feng
Published: February 2020

Metastable pathways allow high rates

In batteries that allow for fast charging and discharging, lithium usually forms a solid solution with the anode so that the only limiting factor is the ionic diffusion. However, for a lithium titanate (Li
4
Ti
5
O
12
) anode, the lithium ions interact with two phases and the diffusion is slow in both, but it still shows high-rate capabilities. Zhang
et al.
used electron energy-loss spectroscopy combined with density functional theory calculations to probe the anomalous behavior. They found that a diffuse interface forms between the starting and ending compositions, Li
4
Ti
5
O
12
and Li
7
Ti
5
O
12
, and this is what allows the lithium ions to travel quickly.

Science
, this issue p.
1030
Tumor neoantigenicity assessment with CSiN score incorporates clonality and immunogenicity to predict immunotherapy outcomes
Authors: Lu Tianshi , Wang Shidan , Xu Lin , Zhou Qinbo , Singla Nirmish , Gao Jianjun , Manna Subrata , Pop Laurentiu , Xie Zhiqun , Chen Mingyi , Luke Jason J. , Brugarolas James , Hannan Raquibul , Wang Tao
Published: February 2020

CSiN score is an improved tool to assess the overall quality of tumor neoantigens that predicts response to immunotherapy.
High-dose vitamin C enhances cancer immunotherapy
Authors: Magrì Alessandro , Germano Giovanni , Lorenzato Annalisa , Lamba Simona , Chilà Rosaria , Montone Monica , Amodio Vito , Ceruti Tommaso , Sassi Francesco , Arena Sabrina , Abrignani Sergio , D’Incalci Maurizio , Zucchetti Massimo , Di Nicolantonio Federica , Bardelli Alberto
Published: February 2020

Vitamin C promotes anticancer adaptive immunity and enhances efficacy of immune checkpoint therapy.
Tolerance induction and microglial engraftment after fetal therapy without conditioning in mice with mucopolysaccharidosis type VII
Authors: Nguyen Quoc-Hung , Witt Russell G. , Wang Bowen , Eikani Carlo , Shea Jeremy , Smith Lucas K. , Boyle Gabrielle , Cadaoas Jaclyn , Sper Renan , MacKenzie John D. , Villeda Saul , MacKenzie Tippi C.
Published: February 2020

In utero therapy with recombinant enzyme or hematopoietic stem cells in MPS7 mice induces tolerance to missing enzyme and corrects brain microglia.
Late-onset mania associated with corticosteroids and small cell lung carcinoma
Authors: El Hayek Samer , El-Khoury Joseph
Published: February 2020

Episodes of mania typically occur in the context of bipolar disorder, with an average age of onset of 25 years. A condition with identical symptoms, known as secondary mania, generally occurs in isolation in older adults and has an identifiable organic etiology. Here, we report a 57-year-old man who presented to the emergency department with a 3 weeks history of sudden onset mania with psychotic symptoms. He had no previous psychiatric history, and his presentation coincided with the initiation of a course of steroids. Despite the absence of physical symptoms, investigations revealed a previously undetected adrenocorticotropic hormone-releasing small cell lung carcinoma that led to his death within months. This case highlights the complexity of distinguishing primary from secondary mania when it occurs after the peak incidence period of early adulthood. Undertaking a comprehensive medical workup is generally recommended.
Identifying return to work trajectories among employees on sick leave due to mental health problems using latent class transition analysis
Authors: Spronken Maitta , Brouwers Evelien P M , Vermunt Jeroen K , Arends Iris , Oerlemans Wido G M , van der Klink Jac J L , Joosen Margot C W
Published: February 2020

Objectives

To develop effective return to work (RTW) interventions for employees on sick leave due to mental health problems (MHPs), a better understanding of individual variation in the RTW process is needed. We investigated which RTW trajectories can be identified among employees with MHPs in terms of RTW duration and relapse occurrence during the RTW process. Additionally, we examined how different RTW trajectories can be described in terms of personal and work characteristics.

Methods

Longitudinal sickness absence registry data were collected retrospectively from the largest Dutch occupational health service. Quantitative RTW information as well as personal and work characteristics were extracted. In total, 9517 employees with a sickness absence due to MHPs were included in the analyses (62 938 data points; RTW durations from 29 to 730 days).

Results

A latent class transition analysis revealed five distinct RTW trajectories, namely (1) fast RTW with little chance of relapse, (2) slow RTW with little chance of relapse, (3) fast RTW with considerable chance of relapse, (4) slow RTW with considerable chance of relapse and (5) very fast RTW with very small chance of relapse. Differences between employees in the slower and faster trajectories were observed regarding gender, age, type of MHP, organisation sector and organisation size but not regarding part-time work.

Conclusions

RTW trajectories among employees with MHPs showed large individual variability and differed on personal and work characteristics. Knowledge on different RTW trajectories and their characteristics contributes to the development of personalised RTW treatments, tailored to specific individuals and organisations.
Prevention versus early detection for long-term control of melanoma and keratinocyte carcinomas: a cost-effectiveness modelling study
Authors: Gordon Louisa , Olsen Catherine , Whiteman David C , Elliott Thomas M , Janda Monika , Green Adele
Published: February 2020

Objective

To compare the long-term economic impact of melanoma prevention by sun protection, with the corresponding impact of early detection of melanoma to decrease melanoma deaths.

Design

Cost-effectiveness analysis using Markov cohort model. Data were primarily from two population-based randomised controlled trials, epidemiological and costing reports, and included flow-on effects for keratinocyte cancers (previously non-melanoma skin cancers) and actinic keratoses.

Setting

Queensland, Australia.

Participants

Men and women with a mean age 50 years modelled for 30 years.

Interventions

Daily sunscreen use (prevention) compared with annual clinical skin examinations (early detection) and comparing these in turn with the status quo.

Primary and secondary outcomes

Costs, counts of melanoma, melanoma deaths, keratinocyte cancers, life years and quality-adjusted life years.

Results

Per 100 000 individuals, for early detection, primary prevention and without intervention, there were 2446, 1364 and 2419 new melanomas, 556, 341 and 567 melanoma deaths, 64 452, 47 682 and 64 659 keratinocyte cancers and £493.5, £386.4 and £406.1 million in economic costs, respectively. There were small differences between prevention and early detection in life years saved (0.09%) and quality-adjusted life years gained (0.10%).

Conclusions

Compared with early detection of melanoma, systematic sunscreen use at a population level will prevent substantial numbers of new skin tumours, melanoma deaths and save healthcare costs. Primary prevention through daily use of sunscreen is a priority for investment in the control of melanoma.
Neuroanatomy of the middle cerebral artery: implications for thrombectomy
Authors: Shapiro Maksim , Raz Eytan , Nossek Erez , Chancellor Breehan , Ishida Koto , Nelson Peter Kim
Published: February 2020

Our perspective on anatomy frequently depends on how this anatomy is utilized in clinical practice, and by which methods knowledge is acquired. The thrombectomy revolution, of which the middle cerebral artery (MCA) is the most common target, is an example of a clinical paradigm shift with a unique perspective on cerebrovascular anatomy. This article reviews important features of MCA anatomy in the context of thrombectomy. Recognizing that variation, frequently explained by evolutionary concepts, is the rule when it comes to branching pattern, vessel morphology, territory, or collateral potential is key to successful thrombectomy strategy.
Prevalence and predictors of heated tobacco product use and its relationship with attempts to quit cigarette smoking among Korean adolescents
Authors: Kang Seo Young , Lee Sungkyu , Cho Hong-Jun
Published: February 2020

Introduction

Heated tobacco products (HTPs) have been available in the Korean market since June 2017. In this study, we examined the prevalence and predictors of HTP use among Korean adolescents and the association between HTP and electronic cigarette (EC) use and attempts to quit conventional cigarette (CC) smoking.

Methods

We analysed the data of a representative sample (n=60 040) of 13–18-year-old middle-school and high-school students in Korea who had participated in the 14th Korea Youth Risk Behavior Web-based Survey in 2018.

Results

The prevalence of ever HTP use among Korean adolescents was 2.9% (men: 4.4%, women: 1.2%), a year after the introduction of HTPs in the Korean market. Furthermore, 81.3% of the 1568 ever HTP users were triple users of HTPs, ECs and CCs. Multivariate analysis revealed that ever HTP use was greater among men, higher-grade students, current CC and/or EC users and risky alcohol drinkers. Among current CC smokers, ever users of ECs (28%–30%) and ever HTP users and current EC users (48%) were more likely to have attempted to quit CC smoking than those who had never used HTPs and ECs. However, there were fewer HTP and/or EC ever users among ever CC smokers who successfully quit smoking.

Conclusions

Many adolescents, especially CC and EC users, had already used HTPs shortly after the introduction of HTPs in Korea. The use of newer types of tobacco products is associated with lower odds of abstinence from CCs; therefore, it is important to protect adolescents from them.
Concise and efficient syntheses of methyl 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate and hygrine
Authors: Ma Xiao-Yan , Huang Jian-Ping , Yang Jing , Liu Xingyong , Hu Xinjun , Huang Sheng-Xiong
Published: February 2020

Methyl 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate and hygrine are important biosynthetic intermediates for tropane alkaloids. We have developed a concise method to synthesize these two compounds from the key intermediate N-methylpyrrolinium cation. Methyl 4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate and hygrine were obtained in four and six steps from commercially available 4,4-diethoxybutylamine with overall yields of 42% and 25%, respectively.
Data-driven study of timelike Compton scattering
Authors: Grocholski O. , Moutarde H. , Pire B. , Sznajder P. , Wagner J.
Published: February 2020

In the framework of collinear QCD factorization, the leading twist scattering amplitudes for deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) are intimately related thanks to analytic properties of leading and next-to-leading order amplitudes. We exploit this welcome feature to make data-driven predictions for TCS observables to be measured in near future experiments. Using a recent extraction of DVCS Compton form factors from most of the existing experimental data for that process, we derive TCS amplitudes and calculate TCS observables only assuming leading-twist dominance. Artificial neural network techniques are used for an essential reduction of model dependency, while a careful propagation of experimental uncertainties is achieved with replica methods. Our analysis allows for stringent tests of the leading twist dominance of DVCS and TCS amplitudes. Moreover, this study helps to understand quantitatively the complementarity of DVCS and TCS measurements to test the universality of generalized parton distributions, which is crucial e.g. to perform the nucleon tomography.
Sensitivity of future hadron colliders to leptoquark pair production in the di-muon di-jets channel
Authors: Allanach B. C. , Corbett Tyler , Madigan Maeve
Published: February 2020

We estimate the future sensitivity of the high luminosity (HL-) and high energy (HE-) modes of the Large Hadron Collider (LHC) and of a 100 TeV future circular collider (FCC-hh) to leptoquark (LQ) pair production in the muon-plus-jet decay mode of each LQ. Such LQs are motivated by the fact that they provide an explanation for the neutral current B-anomalies. For each future collider, Standard Model (SM) backgrounds and detector effects are simulated. From these, sensitivities of each collider are found. Our measures of sensitivity are based upon a Run II ATLAS search, which we also use for validation. We illustrate with a narrow scalar (‘$$S_3$$S3’) LQ and find that, in our channel, the HL-LHC has exclusion sensitivity to LQ masses up to 1.8 TeV, the HE-LHC up to 4.8 TeV and the FCC-hh up to 13.5 TeV.
Isoperimetric equalities for rosettes
Authors: Zwierzyński Michał
Published: February 2020

In this paper, we study the isoperimetric-type equalities for rosettes, i.e. regular closed planar curves with nonvanishing curvature. We find the exact relations between the length and the oriented area of rosettes based on the oriented areas of the Wigner caustic, the Constant Width Measure Set and the Spherical Measure Set. We also study and find new results about the geometry of affine equidistants of rosettes and of the union of rosettes.
P–V criticality in braneworld black holes with logarithmic-corrected entropy
Authors: Shahzad M. Umair , Ashraf M. Zeshan
Published: February 2020

In this paper, we study the effect of thermal fluctuations on the thermodynamics of braneworld black holes. Due to thermal fluctuations, the correction terms will produce various thermodynamical quantities such as enthalpy, entropy and specific heats. We develop the canonical and grand canonical ensembles in the presence of corrected entropy and examine the phase transition of braneworld black holes. It is observed that the braneworld black holes show more stability by utilizing the logarithmic-corrected entropy. Finally, we show that braneworld black holes represent a holographic dual of van der Waals fluid. We utilize logarithmic-corrected entropy and demonstrate the validity of the holographic picture. P–V criticality, critical behaviors and stability of braneworld black holes are also discussed.
Competition Numbers and Phylogeny Numbers of Connected Graphs and Hypergraphs
Authors: Xiong Yanzhen , Zaw Soesoe , Zhu Yinfeng
Published: February 2020

Let D be a digraph. The competition graph of D is the graph having the same vertex set with D and having an edge joining two different vertices if and only if they have at least one common out-neighbor in D. The phylogeny graph of D is the competition graph of the digraph constructed from D by adding loops at all vertices. The competition/phylogeny number of a graph is the least number of vertices to be added to make the graph a competition/phylogeny graph of an acyclic digraph. In this paper, we show that for any integer k there is a connected graph such that its phylogeny number minus its competition number is greater than k. We get similar results for hypergraphs.
A conjecture of Gross and Zagier: Case E(ℚ)tor≅ℤ/2ℤ ⊕ ℤ/2ℤ, ℤ/2ℤ ⊕ ℤ/4ℤ or ℤ/2ℤ ⊕ ℤ/6ℤ
Authors: Byeon Dongho , Kim Taekyung , Yhee Donggeon
Published: February 2020

Let [Formula: see text] be an elliptic curve defined over [Formula: see text] of conductor [Formula: see text], [Formula: see text] the Manin constant of [Formula: see text], and [Formula: see text] the product of Tamagawa numbers of [Formula: see text] at prime divisors of [Formula: see text]. Let [Formula: see text] be an imaginary quadratic field where all prime divisors of [Formula: see text] split in [Formula: see text], [Formula: see text] the Heegner point in [Formula: see text], and [Formula: see text] the Shafarevich–Tate group of [Formula: see text] over [Formula: see text]. Let [Formula: see text] be the number of roots of unity contained in [Formula: see text]. Gross and Zagier conjectured that if [Formula: see text] has infinite order in [Formula: see text], then the integer [Formula: see text] is divisible by [Formula: see text]. In this paper, we show that this conjecture is true if [Formula: see text], [Formula: see text] or [Formula: see text].
Epis, dominions and varieties of commutative posemigroups
Authors: Ahanger S. A. , Shah A. H.
Published: February 2020

We show that the posemigroup dominion of a commutative posemigroup is again a commutative posemigroup and all varieties of commutative posemigroups are epimorphically closed. Next, we show that certain subvarieties of the variety of all commutative posemigroups are saturated. Finally, we show that a commutative posemigroup [Formula: see text] is saturated if [Formula: see text] is saturated for some positive integer [Formula: see text].
Lessons learned from the monitoring of turbidity currents and guidance for future platform designs
Authors: Clare Michael , Lintern D. Gwyn , Rosenberger Kurt , Hughes Clarke John E. , Paull Charles , Gwiazda Roberto , Cartigny Matthieu J. B. , Talling Peter J. , Perara Daniel , Xu Jingping , Parsons Daniel , Jacinto Ricardo Silva , Apprioual Ronan
Published: February 2020

Turbidity currents transport globally significant volumes of sediment and organic carbon into the deep-sea and pose a hazard to critical infrastructure. Despite advances in technology, their powerful nature often damages expensive instruments placed in their path. These challenges mean that turbidity currents have only been measured in a few locations worldwide, in relatively shallow water depths (<<2 km). Here, we share lessons from recent field deployments about how to design the platforms on which instruments are deployed. First, we show how monitoring platforms have been affected by turbidity currents including instability, displacement, tumbling and damage. Second, we relate these issues to specifics of the platform design, such as exposure of large surface area instruments within a flow and inadequate anchoring or seafloor support. Third, we provide recommended modifications to improve design by simplifying mooring configurations, minimizing surface area and enhancing seafloor stability. Finally, we highlight novel multi-point moorings that avoid interaction between the instruments and the flow, and flow-resilient seafloor platforms with innovative engineering design features, such as feet and ballast that can be ejected. Our experience will provide guidance for future deployments, so that more detailed insights can be provided into turbidity current behaviour, in a wider range of settings.
Moist Heat Stress on a Hotter Earth
Authors: Buzan Jonathan R. , Huber Matthew
Published: February 2020

As the world overheats—potentially to conditions warmer than during the three million years over which modern humans evolved—suffering from heat stress will become widespread. Fundamental questions about humans’ thermal tolerance limits are pressing. Understanding heat stress as a process requires linking a network of disciplines, from human health and evolutionary theory to planetary atmospheres and economic modeling. The practical implications of heat stress are equally transdisciplinary, requiring technological, engineering, social, and political decisions to be made in the coming century. Yet relative to the importance of the issue, many of heat stress's crucial aspects, including the relationship between its underlying atmospheric drivers—temperature, moisture, and radiation—remain poorly understood. This review focuses on moist heat stress, describing a theoretical and modeling framework that enables robust prediction of the averaged properties of moist heat stress extremes and their spatial distribution in the future, and draws some implications for human and natural systems from this framework. ▪  Moist heat stress affects society; we summarize drivers of moist heat stress and assess future impacts on societal and global scales. ▪  Moist heat stress pattern scaling of climate models allows research on future heat waves, infrastructure planning, and economic productivity.
Reduced Graphene Oxide Encapsulated Phosphorus-Carbon Composite with Improved Reversibility of Sodium-Ion Storage
Authors: Lee Gi-Hyeok , Jo Mi Ru , Kim Soo Young , Kang Yong-Mook
Published: February 2020

Recently, Na ion battery systems came to the fore again because of their high cost-effectiveness compared to the widely used Li ion battery systems. However, representative Li ion battery anode materials such as graphite and silicon cannot adapt to Na ion battery. So, many researchers have tried to find new anode materials for Na ion battery, and phosphorus has emerged as one of the promising materials. Phosphorus is a prospective anode material substitute for silicon as a high capacity material in Na ion battery. But similar to silicon, poor intrinsic electric conductivity and high volume expansion ratio of phosphorus makes it challenging to be applied as an anode material. To overcome the problems, numerous synthesis processes such as mechanical milling of phosphorus with carbon or other metals, and insertion of phosphorus inside the active carbon by evaporating process have been conducted. However, cyclability and coulombic efficiency of previous materials still needs to be improved in order to make NIB commercially viable. In this study, we encapsulated mechanically milled P/C composite into reduced graphene oxide (rGO) by simple spray-drying to prevent deterioration of the P/C composite. Specifically, we tried to reduce the surface side reaction and volume expansion problem by our design strategy which was helpful to solve the problem due to the outstanding mechanical strength and electric conductivity of rGO. Consequently, rGO encapsulated P/C composite shows improved performance by rGO coating effect in terms of cyclability, rate capability and coulombic efficiency.
Unlock High Capacity of Hard Carbon Anodes in Na-Ion Batteries By Increasing Structural Defects Via Phosphorus Doping
Authors: Li Zhifei , Ma Lu , Surta Todd Wesley , Bommier Clement , Jian Zelang , Xing Zhenyu , Stickle William F. , Dolgos Michelle , Lu Jun , Wu Tianpin , Ji Xiulei
Published: February 2020

Na-ion batteries (NIBs) have received much attention, especially for large-scale energy storage, due to its cost and sustainability advantage over Li-ion batteries (LIBs).  Rapid progress has been made on NIB cathodes, including layered metal oxides and polyanionic compounds.  For the anode side, despite great advances being made on various candidates, futuristic commercialization of NIBs most likely relies on high-performing carbon anodes considering safety, scalability, and cost.  Unfortunately, graphite that works very well for LIBs does not function for NIBs due to the unfavorable thermodynamics between graphite and Na.  Fortunately, nongraphitic carbons as anodes can provide meaningful capacities for NIBs.  Among them, hard carbon also known as nongraphitizable carbon has become the leading candidate since Stevens and Dahn first reported a reversible capacity of ~300 mAh/g on pyrolyzed glucose.  However, the capacity of hard carbon has not been improved much after that.  Herein, we dope heteroatoms, phosphorus to improve the capacity of hard carbon.  The capacity of phosphorus-doped hard carbon (P-HC) was increased to a record high value of 359 mAh/g from 280 mAh/g when up-doped.  In order to learn the mechanism of heteroatom doping, the specific surface area of un-doped hard carbon (HC) and P-HC were controlled to be low, i.e., less than 10 m2/g, for comparison.  Supported by different characterization techniques, we proposed that the doping-induced defects play an important role for the high capacity of P-doped hard carbon.
Nanostructured Carbon Materials for Li-S and Li-Se Batteries
Authors: Dai Fang , Xiao Qiangfeng , Yang Li , Cai Mei
Published: February 2020

Novel energy storage systems with high energy density and reduced cost has drawn significant attention due to the emerging storage application, such as commercial electronic devices, electrical vehicles, and grid storage systems. Conventional Li-ion batteries, however, are hard to meet the requirement for those applications in near future due to the theoretical energy density limit. Therefore, advanced batteries with different chemistry which could provide higher capacity and energy density are necessary for further development. Among many candidates, Lithium-sulfur battery (Li-S) has been recognized as one promising system due to its high gravimetric energy density and low material cost, which is superior to most of current Li-ion batteries. Besides sulfur, selenium (Se) has also been involved in the battery study, since it shares similar lithiation/delithiation mechanism to sulfur. In addition, although with lower gravimetric capacity than sulfur, the better electrical conductivity and less shuttling behavior make selenium parallel path of the sulfur system.

Due to their dissolution nature of both Li-S and Li-Se systems, supporting materials which provide a robust framework with sufficient internal space and reactive sites, are critical for the chemistry. Although there were many candidates for the supporting material in Li-S and Li-Se batteries, such as metal oxides and graphene based materials, porous carbon materials are still dominant for a practical point of view. Relatively low cost, Industrial scale production and convenient handling make porous carbon materials superior to other supporting materials. Here we present a summary of our work on several porous carbon materials as the supporting material, which help enable high S/Se loading on both material level and electrode level, for the Li-S and Li-Se batteries. We will demonstrate the preparation, characterization and electrochemical performance of the carbon materials. The comparison of corresponding Li-S and Li-Se will be also described. Besides carbon materials, we will also discuss about our study on the influence of polymer binder and electrolyte on the optimized electrodes on both Li-S and Li-Se systems. Further discussions on the battery design and cell-level energy density estimation will be also addressed.
Polymer Modified Cathode and Separator for Enhanced Li-S Battery Performance Based on Partially Exfoliated Carbon Nanotube Sulfur Composite Cathode
Authors: S Ramaprabhu , Gangadharan Ananya
Published: February 2020

Lithium sulfur battery has become a hot topic in the current scenario of the ever-increasing energy demand of the world. The availability and non-toxicity of sulfur made the lithium sulfur battery more attractive in scientific research. The high theoretical capacity of the sulfur has been chained by its insulating nature. In order to overcome this hurdle research is directed towards carbon based sulfur composites. The other main issue of lithium sulfur battery is the shuttle mechanism, the intermediate polysulfides dissolves into the electrolyte, which leads to the active material loss. This problem can be tackled by modification on the configuration of the cell. The partially exfoliated multiwalled carbon nanotube coated with a conductive polymer (PEDOT:PSS) can provide a conducting support to the sulfur and can trap the polysulphides at cathode, even though the complete blocking of the polysulphides to the anode still remains a challenge. The modification of the separator with the same polymer will trap the remaining polysulphides and protect the anode from the dendrite formation as well as the deposition of polysulphides. The effective modification of the battery leads to the improved performance, with high energy and power density. The polymer modified cathode and separator helped to prevent the polysulphide deposition on the anode side, and to achieve a capacity of 1000 mAh/g(s).
Atmosphere Assisted Growth of Mn3O4 Balls for Lithium Batteries
Authors: Sun Xiaofei , Xu Zhengyi , Xu Youlong , Zhang Xiaona , Teng Feng , Li Long
Published: February 2020

Transition metal oxides MOx (M=Fe, Co, Mn ···) are being extensively investigated as a group of next generation anode materials for rechargeable lithium batteries, because of their high theoretical specific capacities based on conversion reactions during charging/discharging. Manganese oxides are specially considered also for their low cost and environmental friendliness. In this paper, Mn3O4 with different morphologies, i.e. micro-balls and polyhedral particles (Fig. 1), are prepared by tuning the synthesis atmosphere. The crystallographic structure, particle morphology and electrochemical performance are comprehensively studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic cycling. The relationship between the particle structure and battery performance of different shaped Mn3O4will be comparatively discussed.

This work is financially supported by the Natural Science Foundation of Shaanxi Province (China, Grant No. 2014JQ2-2007), the National Natural Science Foundation of China (Grant No. 21503158), the Fundamental Research Funds for the Central Universities of China (Grant No. xjj2014044) and the 111 Project (Grant No. B14040).

Fig. 1

Figure 1
Understanding the Effect of Polymer Binder on the Electrochemical Performance for Si/C Anodes
Authors: Terborg Lydia , Ross Philip N , Liu Gao , Kostecki Robert
Published: February 2020

With its theoretical capacity of 4200 mAh silicon received significant attention as a viable alternative to graphitic carbon in lithium ion batteries.[1] However, silicon has substantial limitations and suffers from poor passivating behavior in organic electrolytes and top-of-charge electrolyte side reactions, which results in large irreversible capacity loss and gradual electrolyte consumption with a lithium inventory shift, due to poor SEI formation. Furthermore, large crystallographic volume changes (~320%) are observed during cycling, which translates to particle cracking, particle isolation, and electrode delamination. This in turn affects not only the SEI stability but also results in the loss of electrode integrity.

To overcome the loss of electronic connectivity and mechanical integrity of the bulk electrode during extended charge-discharge cycles, it is important to identify an effective polymer binder. Consequently it is essential to understand the effect of polymer binder on the electrochemical performance for Si/C anodes.

On the one hand this study focuses on the determination of the mechanical and adhesion binder properties before and with cycling. Stress-strain curves, indentation measurements and adhesion test give information about properties needed to withstand the large volume changes during cycling. Furthermore the evolution of binder deterioration is monitored and gives information about effect of the polymer binder on adhesion, crack initiation, growth, and particle delamination.

On the other hand, the determination of chemical changes in polymer binders with cycling is carried out. Films of the binder polymers are spin coated onto doped Si wafers using thicknesses of same order of magnitude as those calculated for composite electrodes. Electrochemical studies give information about Li+ doping, reduction and protection layer formation. The film surface exposed to the electrolyte as well as the substrate/binder interface are analyzed in terms of conductivity and chemical changes. By understanding these changes and their significance regarding cell life, effective new binder candidates can be developed, which can lead to more efficient LIB systems.

Acknowledgements

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, under the Applied Battery Research for Transportation (ABR) Program and Award Number DE-EE0006443.

[1] T. D. Hatchard, J. R. Dahn, Journal of the Electrochemical Society 2004, 151, A838.
Surface Modification of Silicon Anodes for Durable and High-Energy Lithium-Ion Batteries
Authors: Ban Chunmei
Published: February 2020

Carbonaceous materials are the dominant anode materials for lithium-ion batteries since their launch by Sony in 1991. Despite the significantly higher energy density found in silicon, unstable interface and volumetric changes during lithiation and delithiation have prevented the move to silicon-based anodes. Materials and morphological design have been focused to mitigate the structural instabilities that arise during lithium insertion and removal. This paper will introduce a different approach, surface modification, that have been developed recently to accommodate volume expansion and contract, but also modify the surface of silicon against electrical isolation following pulverization, and improve the electronic and ionic conductivities of silicon anodes during operation and cycling. Besides wet chemistry, atomic layer deposition (ALD) and molecular layer deposition (MLD) methods have been utilized to produce polymeric hybrid inorganic-organic coating covalently bonded to surface of silicon particles. Improved performance, including high rate capability and durable cycling, has been achieved for the ALD/MLD coated electrodes. To further investigate the impact of surface modification on the electrochemical behavior, in-situ characterization and molecular simulation have been used to study the morphological evolution and surface structure during electrochemical reactions. The data from the synthesis and analysis shed light on the importance of surface modification for silicon-based electrodes. The results provide the information for new design of surface coatings for electrode materials with the aims of achieving durable high-energy-density lithium-ion batteries.
Synthesis and Electrode Performance of KFeF3 for Li- and Na-Ion Batteries
Authors: Kubota Kei , Nakanishi Marie , Komaba Shinichi
Published: February 2020

Among the iron-based positive electrode materials for Li- and Na-ion batteries, FeF3 with high electronegativity of fluorine exhibits high voltage Fe(II/III+) redox couple with excellent electrochemical performances such as high capacity and good cycle stability.[1]  However, FeF3 does not contain an alkali metal in the structure and can be used with limited negative electrode materials containing adequate amount of the alkali metal.  In this study, perovskite-type transition metal fluorides containing potassium, KFeF3, were synthesized and their electrochemical performance was examined.  Furthermore, combined characterization with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray absorption spectroscopy were carried out for the perovskite-type KFeF3 to understand the insertion mechanism in Li and Na cells.

  KFeF3 samples were prepared by liquid-phase reaction from starting materials of FeF2 and KF with ethylene glycol.  The mixed dispersion was heated at 120 ºC for 7 days in a Teflon-lined stainless steel autoclave.  The products were filtered and then dried in air at 80 ºC under vacuum.  Obtained KFeF3 was mixed with acetylene black (AB) at a weight ratio of 7:2 by ball-milling.  Electrochemical properties were tested using a coin-type cell.  Positive electrodes consisted of the active material, AB and polyvinylidenefluoride(PVdF) with a gravimetric ratio of 70:20:10.  Metallic lithium and sodium were used as a negative electrode.  The electrolyte used was 1.0 mol dm-3 LiPF6 / EC:DMC (= 1:1 v/v) and 1.0 mol dm-3 NaPF6 / PC.

  Figure 1 shows charge and discharge curves of KFeF3/AB composite electrodes in Li and Na cells.  Similar potential profiles showing a plateau at ca. 3 V were obtained and reversible capacities of 100 mAh g-1 were delivered in both cells after an initial charge process in which potassium would be partially extracted from the structure.  The partial potassium extraction in the Na cell upon the initial charge was confirmed by SEM-EDS analysis and remained potassium was gradually extracted as a function of cycle number.  The reaction mechanism on the charge/discharge in Li and Na cells will be discussed in detail.

Reference

[1] N. Yabuuchi, S. Komaba et al., J. Mater. Chem., 21, 10035 (2011).

Figure 1