bluuebunny/crossref_metadata_2025 huggingface dataset:
Early repolarisation among athletes
Authors: Claessen Femke M A P , Peeters Heidi A P , Sorgdrager Bastiaan J , van Veldhoven Peter L J
Published: March 2020

Objectives

Traditionally, early repolarisation (ER) is considered a benign ECG variant, predominantly found in youths and athletes. However, a limited number of studies have reported an association between ER and the incidental occurrence of ventricular fibrillation or sudden cardiac death. Yet definite, direct comparisons of the incidence of ER in unselected, contemporary populations in athletes as compared with non-athletes and across different sports are lacking. This study therefore aimed to investigate whether ER is more common among athletes as compared with non-athletes, and if ER patterns differ between sport disciplines based on static and dynamic intensity.

Methods

To assess ER we retrospectively analysed ECGs of 2241 adult subjects (2090 athletes, 151 non-athletes), who had a sports medical screening between 2010 and 2014 in an outpatient clinic. The outcome was tested for confounders in a multivariable logistic regression analysis.

Results

ER was found in 502 athletes (24%). We found a 50% higher prevalence of ER in the athlete group compared with the control group (OR 1.5 (SE 0.34), adjusted 95% CI 1.0 to 2.4) in multivariable analysis. A 30% higher prevalence of ER in the inferior leads only (OR 1.3 (SE 0.38), adjusted 95% CI 0.74 to 2.3), a 120% higher prevalence of ER in the lateral leads only (OR 2.2 (SE 1.0), adjusted 95% CI 0.87 to 5.4), and a 20% higher prevalence of ER in the inferior and lateral leads (OR 1.2 (SE 0.49), adjusted 95% CI 0.55 to 2.7) was found in athletes.

Conclusion

Athletes had a 50% higher prevalence of ER and a 30% higher prevalence of ER in the inferior leads specifically. There was no association between training duration or sports discipline and ER.
Mental health screening: severity and cut-off point sensitivity of the Athlete Psychological Strain Questionnaire in male and female elite athletes
Authors: Rice Simon , Olive Lisa , Gouttebarge Vincent , Parker Alexandra G , Clifton Patrick , Harcourt Peter , Llyod Michael , Kountouris Alex , Smith Ben , Busch Beau , Purcell Rosemary
Published: March 2020

Objectives

To examine the sensitivity/specificity of the Athlete Psychological Strain Questionnaire (APSQ) in both male and female elite athletes, and also assess internal consistency and convergent/divergent validity, and determine discriminative validity relative to current injury status.

Methods

Data were provided by 1093 elite athletes (males n=1007; females n=84). Scale validity and reliability values were benchmarked against validated measures of general psychological distress and well-being. ROC curve analysis determined a range of optimal severity cut-points.

Results

Bias-corrected area under curve (AUC) values supported three APSQ cut-points for moderate (AUC=0.901), high (AUC=0.944) and very high (AUC=0.951) categories. APSQ total score Cronbach coefficients exceeded those observed for the Kessler 10 (K-10). Gender ×injury status interactions were observed for the APSQ total score and K-10, whereby injured female athletes reported higher scores relative to males and non-injured female counterparts.

Conclusion

By providing a range of cut-off scores identifying those scoring in the marginal and elevated ranges, the APSQ may better facilitate earlier identification for male and female elite athletes vulnerable to mental health symptoms and developing syndromes. Use of the APSQ may support sports medicine practitioners and allied health professionals to detect early mental ill health manifestations and facilitate timely management and ideally, remediation of symptoms.
GRACE score and cardiovascular outcomes prediction among the delayed coronary intervention after post-fibrinolytic STEMI patients in a limited PCI-capable hospital
Authors: Chotechuang Yotsawee , Phrommintikul Arintaya , Kuanprasert Srun , Muenpa Roungtiva , Ruengorn Chidchanok , Patumanond Jayanton , Chaichuen Tuanchai , Thanachaikun Noparat , Benjanuwatra Thanawat , Sukonthasarn Apichard
Published: March 2020

Background

In Thailand, due to limited availability of percutaneous coronary intervention (PCI)-capable hospitals, a number of patients with ST-elevation myocardial infarction (STEMI) after fibrinolytic therapy underwent the delayed coronary intervention (24 hours to 2 weeks). Existing tool such as the Global Registry of Acute Coronary Event (GRACE) to define patients at high risk of cardiovascular outcomes has been used widely, except for patients who had the delayed coronary intervention. We, therefore, evaluated the cardiovascular outcomes of STEMI patients who underwent the delayed coronary intervention.

Methods

We retrospectively analysed the data from the PCI-capable hospital (Maharaj Nakorn Chiang Mai Hospital) STEMI registry during the period 2007–2012. Patients who received fibrinolytic treatment (SK) and underwent the delayed coronary intervention were included. The outcomes of the study were 30-day and 6-month composite cardiovascular outcomes (including death, re-hospitalised with acute coronary syndrome, re-hospitalised with heart failure and stroke).

Results

Of all 341 patients included, 229 (67.2%) patients were in the low GRACE score group (<126 points) and 112 (32.8%) patients in the intermediate-high GRACE score group (≥126 points). At 30 days, the composite cardiovascular outcome occurred in 2.2% (n=5) in the low GRACE score group and 11.6% (n=13) in the intermediate-high GRACE score group (p value=0.001). At 6 months, the composite cardiovascular outcomes occurred in 3.9% (n=9) in the low GRACE score group and 13.4% (n=15) in the intermediate-high GRACE score group (p value=0.003). The area under the receiver operating characteristic curve of GRACE score for 6-month composite cardiovascular outcomes was 0.746 (95% CI 0.698 to 0.793).

Conclusion

Intermediate-high GRACE risk STEMI patients after fibrinolytic therapy in limited PCI-capable hospital who underwent the delayed coronary intervention increased 30-day and 6-month cardiovascular outcomes compared with the low GRACE risk patients. In limited available PCI-capable hospital, GRACE risk score can be helpful in guiding the cardiologists to select a proper time for coronary intervention in post-fibrinolytic STEMI patients.
Integrating complementary medicine in the perioperative period: a simple, opioid-sparing addition to your multimodal analgesia strategy?
Authors: Kelleher Deirdre C , Kirksey Meghan A , Wu Christopher L , Cheng Stephanie I
Published: March 2020

The current US opioid health-related crisis underscores the importance for perioperative physicians to optimize various approaches to pain management. Multimodal techniques and enhanced recovery after surgery (ERAS) protocols are frequently cited as the most effective strategies for improving the experience of pain and reducing opioid exposure. Complementary medicine (CM) techniques, while frequently shown to be effective at reducing opioid and other pharmacologic agent use, are rarely discussed as part of these multimodal strategies. In general, CM therapies are low-cost with minimal associated risk, making them an ideal choice for incorporation into ERAS and other opioid-sparing protocols. In this Daring Discourse, we discuss the benefits and challenges of incorporating CM therapy into anesthetic practice. We hope that anesthesiologists can become more familiar with the current evidence regarding perioperative CM therapy, and begin incorporating these therapies as part of their comprehensive multimodal approach to perioperative pain management.
Using point-of-sale data to examine tobacco pricing across neighbourhoods in Scotland
Authors: Shortt Niamh K , Tunstall Helena , Mitchell Richard , Coombes Emma , Jones Andy , Reid Garth , Pearce Jamie
Published: March 2020

Objectives

To assess the geographical variation in tobacco price (cigarettes and roll-your-own (RYO) tobacco) in convenience stores across Scotland and how this relates to neighbourhood income deprivation, tobacco retail outlet density and urban/rural status.

Methods

Tobacco price data from 124 566 shopping baskets purchased in 274 convenience stores during 1 week in April 2018 were obtained through an electronic point-of-sale system. These data were combined with neighbourhood-level measures of income deprivation, tobacco retail outlet density and urban/rural status. We examined brand price for 12 of the most popular cigarette brands and 3 RYO brands and variations in purchases by price segment; multivariable regression analysis assessed associations between area variables and tobacco price.

Results

Most stores sold tobacco in all price segments. The lowest priced subvalue brands were the most popular in all neighbourhoods but were most dominant in shops in more deprived neighbourhoods. When total sales were assessed, overall purchase price varied significantly by neighbourhood income deprivation; packets of 20 cigarettes were 50 pence (5.6%) lower and RYO 34 pence (2.7%) lower among shops in the two highest income deprivation quintiles relative to the lowest. Analysis of individual brands showed that for 3 of the 12 cigarette brands considered, average prices were 12–17 pence lower in more deprived neighbourhoods with the most popular RYO brand 15 pence lower. There was limited evidence of a relationship with tobacco retail outlet density.

Conclusion

Across Scottish convenience stores, the purchase price of cigarettes and RYO was lower in more income-deprived neighbourhoods. The lower prices primarily reflect greater sales of cheap brands in these areas, rather than retailers reducing the prices of individual brands.
Projecting the future impact of past accomplishments in tobacco control
Authors: Maciosek Michael V , St Claire Ann W , Keller Paula A , LaFrance Amy B , Xu Zack , Schillo Barbara
Published: March 2020

Background

The benefits to adults who quit smoking increase over time as former smokers live longer, healthier lives. Youth who never smoke will benefit for decades. Thus, the long-term population effects of tobacco prevention and control policies may be substantial. Yet they are rarely quantified in evaluations of state tobacco control programmes.

Methods

Using a microsimulation model, we predicted the benefits to Minnesotans from 2018 to 2037 of having reduced cigarette smoking prevalence from 1998 to 2017. We first simulated the health and economic harms of tobacco that would have occurred had smoking prevalence stayed at 1997 levels. The harms produced by that scenario were then compared with harms in scenarios with smoking declining at observed rates from 1998 to 2017 and either expected declines from 2018 to 2037 or a greater decline to 5% prevalence in 2037.

Results

With expected smoking prevalence decreases from 2018 to 2037, Minnesotans will experience 12 298 fewer cancers, 72 208 fewer hospitalisations for cardiovascular disease and diabetes, 31 913 fewer respiratory disease hospitalisations, 14 063 fewer smoking-attributable deaths, $10.2 billion less in smoking-attributable medical expenditures and $9.4 billion in productivity gains than if prevalence had stayed at 1997 levels. These gains are two to four times greater than for the previous 20 years, and would be about 15% higher if Minnesota achieves a 5% adult prevalence rate by 2037.

Conclusions

The tobacco control measures implemented from 1998 to 2017 will produce accelerated benefits during 2018–2037 if modest progress in tobacco prevalence rates is maintained.
Laboratory study of low-sulfide tailings covers with elevated water table to prevent acid mine drainage
Authors: Rey Nicolas J. , Demers Isabelle , Bussière Bruno , Mbonimpa Mamert
Published: March 2020

The use of monolayer covers combined with an elevated water table (EWT) is a promising reclamation method that relies on the low gas-diffusivity of water to limit oxygen ingress into potentially acid-generating tailings. A monolayer cover is installed over the sulfidic material and the water table level is controlled to maintain the tailings close to saturation. A protocol including laboratory columns was conducted to evaluate the sensitivity of the technique to parameters including cover thickness, water table level, and the presence of an anti-evaporation layer. Two types of desulfurized tailings were evaluated: silty tailings from Westwood mine and sandy tailings from Goldex mine. Data used to evaluate the covers performances included volumetric water content, suction, oxygen concentrations, and oxygen consumption. Results showed that both cover materials could be used to maintain the reactive tailings at a degree of saturation ≥90% when the EWT level was maintained at a maximum distance of 1 m below the tailings surface. The finer Westwood material showed a better capacity for limiting oxygen migration through the cover, with a maximum flux of 5.7 mol·m−2·year−1 measured near the cover base.
Failure mechanisms in two-layer undrained slopes
Authors: Guo Shuangfeng , Griffiths D.V.
Published: March 2020

This note presents results of stability analyses of two-layer undrained slopes by the finite element method. The study focuses on the circumstances under which either deep or shallow failure mechanisms occur, as a function of the strength ratio of the layers, slope angle, and foundation depth ratio. Improved knowledge of the location of the critical failure mechanism(s) in two-layer systems will give engineers better insight into where to focus their attention in terms or remediation or reinforcement to preserve stability.
Stability coefficient of interlocking compressed earth block masonry under axial compression
Authors: Wang Tianya , Wang Yihong , Zeng Guiyuan , Zhang Jianxiong , Shi Dan
Published: March 2020

To investigate the effects of the height–thickness ratio (β) on the mechanical properties and stability coefficients ([Formula: see text]) of interlocking compressed earth block (ICEB) masonry members under axial compression, four groups of specimens with different β of 3.75, 6.75, 11.25, and 14.25 were tested, thereby assessing their stress process, failure mode, compressive strength, and in- and out-of-plane deformations. All the specimens underwent brittle failure under axial compression: the compressive strength was found to decrease in a range from 5.6% to 43% with increasing β, whereas the initial stacking defects and the in- and out-of-plane deformations increased. The specimens became less stable, and we noticed that the overall damage was caused by strength failure and not instability failures. Because the stability coefficient of ICEB-based masonry components cannot be calculated as those of more conventional brickwork, we combined our results with well-established masonry design guidelines and derived an interlocking improvement coefficient. Finally, we proposed a formula for calculating the axial compression stability coefficient of ICEB masonry that can provide a useful reference for subsequent research on ICEB walls.
Hyperon–nucleon interaction within chiral effective field theory revisited
Authors: Haidenbauer J. , Meißner U.-G. , Nogga A.
Published: March 2020

The$$\varLambda N$$ΛNand$$\varSigma N$$ΣNinteractions are considered at next-to-leading order in SU(3) chiral effective field theory. Different options for the low-energy constants that determine the strength of the contact interactions are explored. Two variants are analysed in detail which yield equivalent results for$$\varLambda N$$ΛNand$$\varSigma N$$ΣNscattering observables but differ in the strength of the$$\varLambda N \rightarrow \varSigma N$$ΛN→ΣNtransition potential. The influence of this difference on predictions for light hypernuclei and on the properties of the$$\varLambda $$Λand$$\varSigma $$Σhyperons in nuclear matter is investigated and discussed. The effect of the variation in the potential strength of the$$\varLambda N$$ΛN-$$\varSigma N$$ΣNcoupling (also called$$\varLambda -\varSigma $$Λ-Σconversion) is found to be moderate for the considered$$^3_\varLambda {{\mathrm{H}}}$$Λ3Hand$$^4_\varLambda \mathrm{He}$$Λ4Hehypernuclei but sizable in case of the matter properties. Further, the size of three-body forces and their relation to different approaches to hypernuclear interactions is discussed.
Erratum to: Entangled neutrino states in a toy model QFT
Authors: Evslin Jarah , Mohammed Hosam , Ciuffoli Emilio , Zhou Yao
Published: March 2020

This was his affiliation when Ref. [1] was in progress, when it was published and even today it is his current affiliation. All other affiliations in the paper were correct at the time of writing. We regret that it was omitted in the original publication.
The $$q_T$$ subtraction method: electroweak corrections and power suppressed contributions
Authors: Buonocore Luca , Grazzini Massimiliano , Tramontano Francesco
Published: March 2020

Building upon the formulation of transverse-momentum resummation for heavy-quark hadroproduction, we present the first application of the $$q_T$$qT subtraction formalism to the computation of electroweak corrections to massive lepton pairs through the Drell–Yan mechanism. We then study the power suppressed contributions to the $$q_T$$qT subtraction formula in the parameter $$r_{\mathrm{cut}}$$rcut, defined as the minimum transverse momentum of the lepton pair normalised to its invariant mass. We analytically compute the leading power correction from initial and final-state radiation to the inclusive cross section. In the case of initial-state radiation the power correction is quadratic in $$r_{\mathrm{cut}}$$rcut and our analytic result is consistent with results previously obtained in the literature. Final-state radiation produces linear contributions in $$r_{\mathrm{cut}}$$rcut that may challenge the efficiency of the $$q_T$$qT subtraction procedure. We explicitly compute the linear power correction in the case of the inclusive cross section and we discuss the extension of our calculation to differential distributions.
The effects of fiber ply orientation, laminate layer and PLA content on mechanical properties of carbon fiber reinforced bioplastic composites
Authors: Murakami R. , Fajri A. , Solafide W.
Published: March 2020

In this study, two kinds of bioplastic materials, where the first consists of 10% PLA, corn starch of 80% and CaCO3 10%, and the second consists of 45% PLA content, corn starch of 45% and CaCO3 10%, were used. The composites were also reinforced by the carbon fibers, which were prepared with one and two layers of carbon fiber and then ply orientations of [0[Formula: see text]] and [45[Formula: see text]]. The maximum tensile strength was observed for PLA 45% with a [0[Formula: see text]] ply orientation of two layers of carbon fiber. For composite with two layers of carbon fiber, the tensile strength showed higher for the [0[Formula: see text]] ply orientation than for the [45[Formula: see text]] ply orientation. The fatigue strength strongly depends on the orientation of carbon fiber, but in the long fatigue life range, the difference of fatigue strength between the fiber ply orientations reduces.
COHERENCE ANALYSIS FOR ITERATED LINE GRAPHS OF MULTI-SUBDIVISION GRAPH
Authors: DAI MEIFENG , ZHU JIE , HUANG FANG , LI YIN , ZHU LINHE , SU WEIYI
Published: March 2020

More and more attention has focused on consensus problem in the study of complex networks. Many researchers investigated consensus dynamics in a linear dynamical system with additive stochastic disturbances. In this paper, we construct iterated line graphs of multi-subdivision graph by applying multi-subdivided-line graph operation. It has been proven that the network coherence can be characterized by the Laplacian spectrum of network. We study the recursion formula of Laplacian eigenvalues of the graphs. After that, we obtain the scalings of the first- and second-order network coherence.
AN INVESTIGATION ON EFFECTIVE THERMAL CONDUCTIVITY OF UNSATURATED FRACTAL POROUS MEDIA WITH ROUGHENED SURFACES
Authors: XIAO BOQI , ZHANG YIDAN , WANG YAN , WANG WEI , CHEN HANXIN , CHEN XUBING , LONG GONGBO
Published: March 2020

The effective thermal conductivity of unsaturated porous media is of interest in a number of applications of heat transfer. In this paper, a novel fractal solution for effective thermal conductivity is derived based on the fractal distribution of surface roughness and pore size in unsaturated porous media with roughened surfaces. The proposed fractal model explicitly relates the effective thermal conductivity to the microstructural parameters (relative roughness, porosity and fractal dimensions). The proposed fractal model is verified by a satisfying agreement of the effective thermal conductivity predicted by our model and that reported as existing experimental data in the literature. A parametric study is also elaborated to investigate the influences of the microstructural parameters on the effective thermal conductivity. The results demonstrate that our proposed fractal model improves our understanding of the physical mechanisms of heat transport through unsaturated porous media with roughened surfaces. One advantage of our fractal analytical model is that it contains no empirical constant, while it is usually required in previous models.
AHLFORS–DAVID REGULAR SUBSETS OF FRACTALS
Authors: PAN YUE , XIONG YING
Published: March 2020

This paper focus on the compact Ahlfors–David regular subsets of fractals. For this, we introduce the Ahlfors–David regular dimension and study its basic properties. Based on these properties and some known results in dimension theory of fractals, we compute Ahlfors–David Regular dimension for Moran sets and McMullen sets.
STUDY ON THE DYNAMIC EVOLUTION LAW OF THE EFFECTIVE STRESS IN THE COAL SEAM WATER INFUSION PROCESS BASED ON FRACTAL THEORY
Authors: YANG HE , CHENG WEIMIN , LIU ZHEN , WANG WENDI , ZHAO DAWEI , YANG WENZHI
Published: March 2020

The effect of the coal seam water infusion to reduce dust is directly related to the development degree of the coal structure under the action of the effective stress. Therefore, this paper first summarizes several basic effective-stress models and proposes the effective-stress model considering the capillary force. Thereafter, the nuclear magnetic resonance (NMR) experiment system high-voltage seepage module is used to achieve the saturation coal sample T[Formula: see text] and water infusion coal sample T2test under different mechanical environments. And the fractal dimension was calculated based on the results of porosity and pore size test. Finally, the parameters were sequentially substituted into effective-stress models. The calculation results were compared and analyzed. The results show that the saturation levels of the irreducible fluid of Sample DLT and Sample XLZ are 92.93% and 93.66%, respectively, indicating that these samples are dense porous media structures. Meanwhile, the porosity test shows the overall porosity with the water infusion pressure and confining pressure changes being consistent with the conventional law; the partial porosity caused a slight fluctuation due to different sensitivities of different pores to stress. The effective stresses of the capillary force and the calculated effective stress of the body are closest to the fractal effective stress, so the difference between the two values is negligible due to the small capillary force, which indicates that during the high-pressure water infusion, the capillary force in the meso-structure hardly affects the mechanical environment. Based on the theoretical research results, this paper can provide a theoretical reference for the determination of water infusion parameters under different on-site mechanical environment during the process of coal seam water infusion, which is conducive to the popularization and application of this technology, thus, providing the scientific basis for safe mining of the deep coal seam and ensuring the safe and efficient production of mines.
FRACTAL NETWORKS ON SIERPINSKI-TYPE POLYGON
Authors: ZENG CHENG , XUE YUMEI , ZHOU MENG
Published: March 2020

In this paper, the evolving networks are created from a series of Sierpinski-type polygon by applying the encoding method in fractal and symbolic dynamical system. Based on the self-similar structures of our networks, we study the cumulative degree distribution, the clustering coefficient and the standardized average path length. The power-law exponent of the cumulative degree distribution is deduced to be [Formula: see text] and the average clustering coefficients have a uniform lower bound [Formula: see text]. Moreover, we find the asymptotic formula of the average path length of our proposed networks. These results show the scale-free and the small-world effects of these networks.
Insights from the Physicochemical and Electrochemical Screening of the Potentiality of the Chemically Synthesized Polyaniline
Authors: Djara Razik , Holade Yaovi , Merzouki Abdelhafid , Masquelez Nathalie , Cot Didier , Rebiere Bertrand , Petit Eddy , Huguet Patrice , Canaff Christine , Morisset Sophie , Napporn Teko W. , Cornu David , Tingry Sophie
Published: March 2020

Polyaniline (PANI) is a candidate for electrocatalysis, and can be combined with metal nanoparticles to fabricate high-performance electrodes for electrochemical energy conversion and storage. However, its intrinsic properties appear to be dependent on the synthesis conditions so that from the majority of the reports, it is quite difficult to establish an overall performance trend. In this contribution, we report an extensive and systematic physicochemical and electrochemical screening of the potentiality of chemically synthesized PANI as an electrode material to provide an overall understanding of the effect of the entire synthesis conditions. We have integrated different methods (TGA-DSC, XRD, SEM, EDX, FTIR, BET, CHNS, XPS, CV, and EIS) to deeply examine the as-synthesized materials and interrogate their electrocatalytic efficiency towards hydrogen evolution reaction, which was chosen as a model reaction of critical importance for H2 production from water splitting. It was found that all the synthesis parameters affect strongly the physical and electrochemical characteristics of the PANI-based materials. Specifically, XPS analysis contributed to identify the oxidation levels of the PANI samples on the basis of oxidizing agents. The outcomes provided by the study delineate a rational pathway for the further design and fabrication of PANI-based metal nanoparticles as advanced electrode materials.
Wang‐Bi Capsule Alleviates the Joint Inflammation and Bone Destruction in Mice with Collagen‐Induced Arthritis
Authors: Cui Hua , Shu Haiyang , Fan Dancai , Wang Xinyu , Zhao Ning , Lu Cheng , Lu Aiping , He Xiaojuan
Published: March 2020

Wang‐Bi Capsule (WB), a traditional Chinese medicine‐ (TCM‐) based herbal formula, is currently used in clinic for the treatment of rheumatoid arthritis (RA) with positive clinical effects. However, its pharmacological mechanism of action in RA is still obscure. Therefore, this study established a collagen‐induced arthritis (CIA) mice model to examine the efficacy of WB by using arthritis score, histological analysis, and micro‐CT examination. Proinflammatory cytokines expression, osteoclast number, OPG/RANKL system, and NF‐κB activation were then detected to further investigate the mechanism of WB in RA treatment. The results indicated that WB could alleviate the erythema and swelling of paws in CIA mice. It also inhibited the infiltration of inflammatory cells and bone destruction and increased bone density in joints of CIA mice. Mechanistic studies showed that WB treatment decreased the production of IL‐1β, IL‐6, and TNF‐α in serum and joints of CIA mice. Moreover, it reduced the osteoclast number, increased OPG level, decreased RANKL level, and inhibited the activation of NF‐κB in joints of CIA mice. In conclusion, this study demonstrated that WB could effectively alleviate disease progression of CIA mice by decreasing the IL‐1β, IL‐6, and TNF‐α levels, modulating the OPG/RANKL system, and inhibiting the activation of NF‐κB.
A Framework of Multilayer Multiphase Interleaved Converter for Electric Vehicle Based on Graph Theory
Authors: Yang Bochao , Hu Pinduan , Li Teng , Song Dawei , Shan Zhifei , Dai Shuailong , Li Mengfan
Published: March 2020

Lithium-ion batteries play an important role in large-scale energy storage systems. However, the power inconsistency of the battery packs restricts the developments of modern technologies in energy storage area. The motivation of the present study is to serve the growing needs of the energy balance for lithium-ion battery packs. The present study proposes a flexible multiphase interleaved converter for the energy equalization of a lithium battery pack with series configuration. Moreover, the graph theory is applied to the analysis of equalization circuits. It is intended to establish a unified standard for the comparison. The parameter of average efficiency is considered as an important indicator to evaluate the characteristics of the equilibrium system. The proposed method is verified by constructing a lithium-ion battery pack with the equalization circuit. It is observed that the proposed multiphase interleaved converter has flexible characteristics, while it has low energy loss compared with the conventional methods. It is found that the proposed method simplifies the complex equalization circuits into graphs and facilitates the comparison of the average efficiency of the system. It is concluded that this method is a feasible and powerful method for evaluating the battery equalization circuit. This approach can be applied for solving complex problems in other engineering applications.
Dynamic Modeling of Gear System Based on 3D Finite Element Model and Its Application in Spalling Fault Analysis
Authors: Wan Zhiguo , Dou Yihua , Guan Yuan , Meng Qi , Li Suobin
Published: March 2020

A reduced-order dynamic model, based on three-dimensional (3D) finite element model (FEM) and component modal synthesis technique (CMS), was presented for simulating the dynamic behavior of the spur gear system. The gear shaft and gear body were established via 3D elements to simulate bending and torsion of the gear system. The CMS technique was used to generate a reduced-order model of a spur gear system. A pair of mating teeth was assimilated to two different foundations (one for the pinion tooth and the other one for the gear tooth) linked in series by some independent springs, which was used to simulate the contact stiffness. The validity of the proposed model was verified by static analysis, dynamic analysis, and experimental analysis. The results show that the proposed model is an effective model. In addition, the proposed model has also been applied to analyze spur gear spalling faults. The results show that the dynamic response of the gear system is periodic vibration shock response due to the alternate meshing of single and double teeth. When the spalling fault occurs, some shock responses with significantly enhanced amplitude will be generated as the result of contact loss.
Application of Similarity Theory for Dynamic Characteristics Prediction of Crane Flexible Truss Boom
Authors: Cao Xuyang , Wang Zhiwei , Wang Wenjun , Dong Xiang
Published: March 2020

The aim of this study is to explore the similarity relations of dynamic characteristics of crane flexible truss boom. Combining perturbation theory with vibration analysis, a calculation method of the flexible boom natural frequency undergoing large overall rotary motion was proposed. According to the similarity theory, in terms of the geometrically similar truss boom, the similarity relations of their natural frequency and other parameters were derived. Taking the slenderness ratio of the actual product as the reference standard, two groups of scale-down crane truss boom experiments were designed. The results showed that, in aspect of the boom section size and the boom length, by using the similarity relations of the flexible boom, the dynamic characteristics can be predicted well.
Research on Chaos Response of the Nonlinear Vibration System of Giant Magnetostrictive Actuator
Authors: Yan Hongbo , Niu Yu , Gao Hong , Hao Hongbo
Published: March 2020

In the present study, the chaotic response of the nonlinear magnetostrictive actuator (GMA) vibration system is investigated. The mathematical model of the nonlinear GMA vibration system is established according to J-A hysteresis nonlinear model, quadratic domain rotation model, Newton’s third law, and principle of GMA structural dynamics by analyzing the working principle of GMA. Then, the Melnikov function method is applied to the threshold condition of the chaotic response of the system to obtain the sense of Smale horseshoe transformation. Furthermore, the mathematical model is solved to investigate the system response to the excitation force and frequency. Accordingly, the corresponding displacement waveform, phase plane trajectory, Poincaré map, and amplitude spectrum are obtained. The experimental simulation is verified using Adams software. The obtained results show that the vibration equation of the nonlinear GMA vibration system has nonlinear and complex motion characteristics with different motion patterns. It is found that the vibration characteristics of the system can be controlled through adjusting the excitation force and frequency.
Performance Analysis of Prefabricated Steel‐Spring Floating‐Slab Track and Its Application to Urban Express Rail Transit
Authors: Huang Xudong , Li Ping , Luo Xinwei , Ling Liang , Shuaibu Abdulmumin Ahmed , Zeng Zhiping
Published: March 2020

The aim of the research is the design of prefabricated steel‐spring floating‐slab track to be applied in urban express rail transit systems. Using a developed vehicle‐track dynamic‐coupling equation for steel‐spring floating‐slab track, the effects of length, thickness, vertical damping, and use of side‐mounted isolators on the floating‐slab track were investigated experimentally using full‐scale model and under different working conditions. The finding of the study revealed the following: (1) The prefabricated steel‐spring floating‐slab track can be applied to urban express rail transit, because it meets the requirements of high‐speed transit while efficiently reducing noise. (2) The floating‐slab track’s stability slightly increases with the increase of its length and thickness. As thickness increases, vertical displacement of the rail increases slightly, and lateral stability increases, thereby slightly improving the vehicle’s running stability. (3) When the intercity electric multiple‐unit train travels along the prefabricated steel‐spring floating‐slab‐track bed at different speeds, the wheel‐axle lateral force, wheel‐rail vertical force, the derailment coefficient, the wheel‐weight reduction rate, and the lateral acceleration of the vehicle body are all less than the specified limits of Chinese code, thus fully meeting the safety requirements of train operation. (4) Appropriately increasing the vertical‐support damping of the floating slab can improve the vehicle’s vertical dynamic performance, reduce the vertical displacement of the rail, and lower the vibration response of the floating slab. (5) Adding side‐mounted vibration isolators at the joint of the floating slab could greatly improve the stability of the floating slab itself and appropriately reduce the vehicle’s vertical vibration response. Due to the optimization and establishment of relevant factors influencing the performance of prefabricated steel‐string floating‐slab track achieved in the study, the results obtained are particularly useful for setting safety, comfort, and stability requirements of the floating slab.
Selenium-Enriched Yeast Alleviates Oxidative Stress-Induced Intestinal Mucosa Disruption in Weaned Pigs
Authors: Liu Lei , Wu Caimei , Chen Daiwen , Yu Bing , Huang Zhiqing , Luo Yuheng , Zheng Ping , Mao Xiangbing , Yu Jie , Luo Junqiu , Yan Hui , He Jun
Published: March 2020

To explore the effect of selenium-enriched yeast (SeY) on intestinal barrier functions in weaned pigs upon oxidative stress, a 2×2 factorial design was utilized and thirty-two pigs were randomly assigned into four groups. Pigs with or without exposure to oxidative stress (diquat challenge) were fed with a basal diet or a SeY-containing diet. The trial lasted for 21 days, and result showed that SeY supplementation attenuated body-weight reduction and significantly decreased the serum concentrations of diamine oxidase (DAO) and D-lactic acid in pigs upon diquat challenge (P<0.05). Diquat challenge decreased the villus height and the ratio of villus height to crypt depth (V/C) in the jejunum and ileum (P<0.05). However, SeY supplementation not only elevated the villus height and the ratio of V/C (P<0.05) but also improved the distribution and abundance of tight-junction protein ZO-1 in the jejunum epithelium. Interestingly, SeY supplementation acutely decreased the total apoptosis rate of intestinal epithelial cells in pigs upon diquat challenge (P<0.05). Moreover, SeY elevated the content of antioxidant molecules such as glutathione peroxidase (GSH-Px) and catalase (CAT) but significantly decreased the content of malondialdehyde (MDA) in the intestinal mucosa (P<0.05). Importantly, SeY elevated the expression levels of critical functional genes such as the nuclear factor erythroid-2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), sodium/glucose cotransporter 1 (SGLT1), and B-cell lymphoma-2 (BCL-2) in the intestinal mucosa upon diquat challenge (P<0.05). Moreover, the expression of caspase-3 was downregulated by SeY in the duodenum and jejunum mucosa (P<0.05). These results indicated that SeY attenuated oxidative stress-induced intestinal mucosa disruption, which was associated with elevated mucosal antioxidative capacity and improved intestinal barrier functions.
Real‐Time Optimization of Precast Concrete Component Transportation and Storage
Authors: Liu Donghai , Li Xin , Chen Junjie , Jin Rui
Published: March 2020

The construction of prefabricated concrete structures involves many different types of precast concrete (PC) components. Improper arrangements of the transportation, storage, and hoisting of the PC components could lead to unnecessary relocation of PC components, causing a delay in construction progress. To address this problem, this paper presented a dynamic optimization method for PC component transportation and storage based on real‐time scheduling and tracking. The real‐time schedule can be extracted from a 4D building information model (BIM), and the position of PC components during the whole transportation process is tracked by a proposed tracking system which integrates the global navigation satellite system (GNSS) and the radio frequency identification (RFID) technology. A transportation optimization model was built to obtain a reasonable transportation plan based on real‐time construction progress. A cyclic operation network (CYCLONE) simulation model for component storing and hoisting was proposed to calculate the on‐site transportation time. A storage optimization model was proposed by considering the real‐time transportation information to optimize the storage mode and storage position in the yard. The proposed models were solved in the context of a case study, which indicates that our method can reduce the on‐site transportation time by 37% and effectively control the relocation times.
Research on Joint Control of On-Ramp Metering and Mainline Speed Guidance in the Urban Expressway Based on MPC and Connected Vehicles
Authors: Wu Lina , Ci Yusheng , Sun Yichen , Qi Wei
Published: March 2020

The traffic operational efficiency of the urban expressway system will affect one of the entire cities. Moreover, the idea that traffic control can improve the traffic operational efficiency of the urban expressway system has been fully confirmed. At present, the main control methods include on-ramp metering and speed guidance control. However, there is a gap in using these two control methods together, such as unclear application conditions and unsystematic methods. In this paper, on-ramp metering and speed guidance control are combined effectively. Based on the research of METANET macroscopic traffic flow model and model predictive control (MPC), a novel joint control method based on MPC and connected vehicles (CVs) for on-ramp metering and speed guidance control of the urban expressway is proposed. Finally, the simulation results show that the proposed control method can effectively improve the traffic efficiency and traffic safety.
Antiaging Factor Klotho Retards the Progress of Intervertebral Disc Degeneration through the Toll-Like Receptor 4-NF-κB Pathway
Authors: Bi Fangfang , Liu Wenbo , Wu Zongtao , Ji Chen , Chang Cuicui
Published: March 2020

Antiaging protein Klotho exhibits impressive properties of anti-inflammation, however is declined early after intervertebral disc injury, making Klotho restoration an attractive strategy of treating intervertebral disc inflammatory disorders. Here, we have found that Klotho is enriched in nucleus pulposus (NP) cells and Klotho overexpression attenuates H2O2-induced acute inflammation essentially via suppressing Toll-like receptor 4 (TLR4). The proinflammatory NF-κB signaling and cytokine expressions paralleled with Klotho repression and TLR4 elevation in both NP cells (H2O2 treatment) and rat intervertebral disc (needle puncture treatment). Overexpression of TLR4 downregulated expression of Klotho, whereas interfering TLR4 expression diminished the inhibitory effects of H2O2 on Klotho in NP cells. Consistently, Klotho knockdown by RNA interferences largely diminished the anti-inflammatory and intervertebral disc protective effects in an Intervertebral Disc Degeneration (IDD) model. Thus, our study indicates that TLR4-NF-κB signaling and Klotho form a negative-feedback loop in NP cells. Also, we demonstrate that the expression of Klotho is regulated by the balance between upregulation and downregulation of TLR4-NF-κB signaling.
In VitroBiofilm Formation and Antibiotic Susceptibility Patterns of Bacteria from Suspected External Eye Infected Patients Attending Ophthalmology Clinic, Southwest Ethiopia
Authors: Diriba Kuma , Kassa Tesfaye , Alemu Yared , Bekele Sisay
Published: March 2020

Background. Ocular disease with its complications is a major public health problem which has significant impacts on the quality of life particularly in developing countries. An eye infection due to bacterial agents can lead to reduced vision and blindness. This study was aimed to assess the antimicrobial susceptibility pattern and biofilm-forming potential of bacteria isolated from suspected external eye infected patients in Jimma.Method. A cross-sectional facility-based study was conducted on 319 suspect patients with external eye infections from March to June 2017 at Jimma University Medical Center (JUMC) Ophthalmology Department in Ethiopia. External ocular specimens were collected and standard operating procedures were followed to handle and culture throughout the study period. Antimicrobial susceptibility was determined by the disk diffusion method according to CLSI guidelines. Microtiter (96 wells) plate method was used to screen biofilm formation by ELISA reader at 570 nm.Results. Out of 319 study participants with an external eye infection, the prevalence of bacterial pathogens was 46.1%. The predominant bacterial isolates were coagulase-negative staphylococcus (CoNS) (27.7%) followed byStaphylococcus aureus(19.7%). Among Gram-negative groups,Pseudomonas aeruginosa(6.8%) was the leading isolate. Increased antimicrobial resistance was observed for tetracycline (64%), erythromycin (66.7%), and penicillin (77.1%). Amoxicillin-clavulanic acid, ciprofloxacin, and gentamicin were the most effective drugs for external eye infections due to susceptibility ranging from 70 to 100% among both Gram-negative and Gram-positive groups. Methicillin-resistantS. aureus(MRSA) accounted for 13.8%. Multidrug resistance (MDR) accounted for 68.7%. The overall biofilm formation rate of bacterial ocular pathogens was 66.1%, whereP. aeruginosa(40%), CoNS (34.1%), andS. aureus(31%) formed strong biofilm phenotype.Conclusion. The prevalence rate of bacterial isolates was high. Almost all bacterial isolates were resistant to at least one or more drugs. MDR pathogens were observed increasingly among biofilm formers or vice versa.
Asymptotic Behavior of a Predator-Prey Model with Allee Threshold Applied to Online Social Network Users’ Data Forwarding
Authors: Zhang Yaming , Koura Yaya Hamadou , Su Yanyuan
Published: March 2020

We consider a predator-prey relationship in a fair system in which interacting species have different needs of resources to survive. We analyzed qualitatively the outcome of interaction using a modified logistic predator-prey model with Allee threshold in both predator and prey equations. We showed that the system had very rich dynamical behavior as stability around fixed points and periodic solutions could be obtained at certain conditions. Interaction outcome is highly submitted to initial conditions, species behavior, and the threshold applied. Numerical results suggested adapting resource allocation and the threshold value to optimize ecosystem sustainability.
Effect of Absorption and Scattering on Fluorescence of Buried Tumours
Authors: Alghourani Kawthar M. K. , Bachir Wesam , Karraz George
Published: March 2020

Fluorescence spectroscopy is widely used for biomedical optical diagnosis and surgical resection of tumours. This work investigates laser-induced fluorescence spectroscopy of fluorescence inclusions that are embedded in turbid media. 405 nm laser diode is used for exciting buried protoporphyrin- (PpIX) based inclusions in brain-like optical phantoms. Effects of scattering and absorption of the turbid medium on the recorded fluorescence signal and depth-resolved fluorescence were studied. Results show that optical properties of the surrounding turbid medium influence the intensity of the fluorescence signal. Absorption coefficient of the surrounding medium is the major contributor to the fluorescent signal. Analysis of the recorded fluorescence spectra shows that the effect of absorption coefficient is larger than the effect of scattering coefficient on the fluorescence intensity by nearly fivefold. The findings indicate that the fluorescence signal could be used as a biomarker of optical property variations through different stages of malignancy. This can enhance the detectability of malignant tissue for diagnostic and surgical purposes as well.