bluuebunny/crossref_metadata_2025_split huggingface dataset:
An updated meta-analysis showed smoking modify the association of GSTM1 null genotype on the risk of coronary heart disease
Authors: Song Yadong , Shan Zhilei , Liu Xiaoli , Chen Xiaomin , Luo Cheng , Chen Liangkai , Wang Yimei , Gong Lin , Liu Liegang , Liang Jiansheng 
Published: January 2021

Abstract
Background Oxidative stress is considered to be involved in the pathogenesis of coronary heart disease (CHD). Glutathione-S-transferase (GST) enzymes play important roles in antioxidant defenses and may influence CHD risk. The present meta-analysis was performed to investigate the link between glutathione S-transferase M1 (GSTM1) null genotype and CHD and to get a precise evaluation of interaction between GSTM1 null genotype and smoking by the case-only design.
Methods PubMed and EMBASE databases were searched through 15 December 2020 to retrieve articles. Odds ratios (ORs) were pooled using either fixed-effects or random-effects models.
Results Thirty-seven studies showed that GSTM1 null genotype was associated with risk of CHD in total population, Caucasians and Asians (for total population, OR = 1.38, 95% confidence interval (CI): 1.15, 1.65; for Caucasians, OR = 1.34, 95% CI: 1.04, 1.72; for Asians, OR = 1.40, 95% CI: 1.11, 1.77). After adjustment for heterogeneity, these relationships were still significant. After adjustment for heterogeneity, case-only analysis of 11 studies showed a positive multiplicative interaction between GSTM1 null genotype and smoking (ever smoking vs. never smoking) (OR = 1.27, 95% CI: 1.08, 1.50; I2 = 0%, P=0.553).
Conclusions The overall results indicated that GSTM1 null genotype was associated with a higher risk of CHD, and the association may be affected by smoking status. This is the first meta-analysis to prove a positive effect of the interaction between GSTM1 null genotype and smoking status on the risk of CHD. Well-designed studies are needed to investigate the possible gene–gene or gene–environment interactions.
Ultra‐low power voltage reference with 40 μA maximum load current for passive sensor systems
Authors: Wang Maodong , Xu Wenjie , Yan Na , Min Hao 
Published: January 2021

AbstractAn ultra‐low power, low temperature coefficient voltage reference generator used for nanowatt‐level passive sensor systems is presented. The voltage reference configuration, based on a voltage reference generating circuit embedded in the feedback loop, realises an average reference voltage (VREF) of 837.2 mV and 40 μA maximum load current. The temperature coefficient of VREF is compensated by a saturated diode‐connected the positive channel Metal Oxide Semiconductor (PMOS) and a proportional to absolute temperature current. For supply voltages ranging from 0.86 to 3 V, this proposed voltage reference simulated in 55 nm a Complementary Metal Oxide Semiconductor (CMOS) process consumes an average current of 10 nA at room temperature and achieves a minimum temperature coefficient of 8.1 ppm/°C from −40°C to 125°C. The mean line sensitivity is 0.17%/V and the coefficient of variation is 2.1%.
Fourier ptychography algorithm based on scaled Fourier transform
Authors: Hasanzade Mojde , Hussain Nazabat , Breiby Dag W. , Akram Muhammad N. 
Published: January 2021

AbstractThis letter discusses an alternative Fourier ptychography algorithm based on the scaled fast Fourier transform propagation. The advantage of this scheme is that it enables a zoom‐in capability of the object spectrum and complex pupil within the synthetic numerical aperture without increasing the overall matrix size. Thus, the high‐resolution complex object and complex pupil are recovered utilising a larger fraction of the elements in their respective representation matrices. Experimental results are presented showing the performance of this scheme against the tradition fast‐Fourier‐transform‐based approach.
A PolSAR despeckling method based on Wishart gradient and anisotropic diffusion
Authors: Wang Hongmiao , Zeng Liang , Zhang Tao , Yin Junjun , Yang Jian 
Published: January 2021

AbstractThe anisotropic diffusion filtering is a classical tool in image processing due to its simplicity and effectiveness. In this letter, we propose a new diffusion‐like filter based on the polarimetric synthetic aperture radar (PolSAR) ratio gradients. The PolSAR ratio gradients combine the information of different polarisation channels and describe the local directional changes in polarimetric characteristics. The proposed filter is then built by utilising the new gradients to derive the diffusion coefficients. The experimental results on synthetic data and real PolSAR images demonstrate the superiority and effectiveness of the new method.
The suppression of DC‐link voltage fluctuations through a source active current feedforward in the active power filter
Authors: Meng Runquan , Du Yi , Han Xiaoqing , Wang Peng 
Published: January 2021

AbstractAn active power filter (APF), which operates under the power‐balance‐based scheme (PB scheme), suffers heavier DC‐link voltage fluctuation when the loads change suddenly, so that it is apt to be interfered and degraded or even out of stable operation. By analyzing the cause of DC‐link voltage fluctuation, this study proposes an improved PB scheme which feeds forward the increment of the fundamental‐frequency positive sequence component of the source current. The feed‐forward channel is designed by use of the cascaded delayed signal cancellation algorithm and integrated into the conventional PB scheme APF without adding any extra hardware circuit. The current increment fed forward is added into the output of the voltage controller to timely amend the reference current of the current control loop, and thus the active power flow, which caused by loads change, between the APF and its external circuitry can be suppressed. As a result, the DC‐link voltage fluctuation is mitigated to allow the APF to better accommodate the abrupt load changes. The configuration of the improved control system is introduced and the stability is analysed. The experiment results demonstrate the effectiveness of the proposed control scheme.
A safe commutation strategy based on LRCD snubber circuit for five‐level active neutral point clamped inverter
Authors: Ye Weiwei , Nie Ziling , Zhu Junjie , Xu Jie 
Published: January 2021

AbstractSpike voltage generated during the turn‐off transient is one of the key threats to IGBT. When the traditional RCD snubber is applied in the five‐level active neutral point clamped (5L‐ANPC) inverter to clamp the spike voltage, a transient large current caused by the charging of the snubber capacitor will increase power losses and current stresses of IGBTs. This study proposes a LRCD snubber for the 5L‐ANPC inverter. It can effectively suppress the spike voltages and the transient large currents of IGBTs, thus reducing the power loss. For the 5L‐ANPC inverter, the traditional commutation method also poses a threat to IGBTs. Near the zero‐crossing point of the output voltage, the traditional commutation method will cause the IGBTs that operate at the carrier frequency to withstand three times of the rated voltage. This study proposes a safe commutation strategy based on the LRCD snubber. When the output voltage passes through zero‐crossing point, the proposed commutation strategy uses four transition switching states to avoid the breakdown of IGBTs induced by overvoltage. It can ensure that all the IGBTs operate in the safe operating area (SOA). Experimental results are presented to verify the validity of the proposed method.
Bidirectional multi‐resonant converter with a wide voltage range
Authors: Zhao Qinglin , Wu Na , Wang Yujie , Wang Deyu , Yang Qiuxia 
Published: January 2021

AbstractA bidirectional multi‐resonant DC/DC converter is proposed in this study. The structure of the converter is symmetrical, and the operating characteristics of the bidirectional operation mode are the same. Adopting synchronous driving, the converter can regulate the output voltage over a wide range. Regardless of a forward mode or reverse mode, the switches of the converter can realise zero‐voltage switching over the entire voltage range. The gain of the converter can be zero due to its characteristics similar to the notch filtre. The converter can transmit the fundamental wave and the third harmonic at the same time, and the energy utilisation rate is high. The converter has a wide voltage range and high efficiency at the same time. A 3.3 kW experimental prototype is designed. In forward mode, the secondary‐side voltage varies from 250 to 450 V, and the peak efficiency is 97.7%. In reverse mode, the secondary‐side voltage varies from 300 to 450 V, and the peak efficiency is 97.6%.
Meta‐heuristic optimisation approach for wave energy converter design by means of a stochastic hydrodynamic model
Authors: Blanco Marcos , Santos‐Herran Miguel , Navarro Gustavo , Torres Jorge , Najera Jorge , Villaba Isabel , Lafoz Marcos , Ramírez Dionisio 
Published: January 2021

AbstractA methodology to automate the sizing of a wave energy converter (WEC) is presented. The preliminary design of WEC geometry is addressed as a mathematical program by means of a meta‐heuristic optimisation, which includes as key aspects the use of a multi‐objective differential evolutionary (DE) algorithm and the implementation of a stochastic hydrodynamic model of the WEC. In this methodology, the WEC concept, the control strategy, the power take‐off characteristics and the location have been taken into consideration due to their strong influence on the WEC design. As a case example, a real project has been selected, and the methodology has been applied to two test locations. Stochastic models are used to handle irregular sea states and to obtain statistical information while reducing the calculation effort when compared to time‐domain models. The output derived from the proposed methodology is a set of feasible solutions so‐called Pareto frontier. These solutions can be used as inputs for a detailed design process. Data from real projects could be used to further develop the sizing methodology by improving the algorithm convergence, refining the requirements, or including new restrictions.
Comparative static and dynamic analysis of single‐ and double‐stage multifunctional 3‐phase grid‐tied photovoltaic systems
Authors: Silveira Rafaela Dizaró , da Silva Sérgio A. Oliveira , Sampaio Leonardo P. , Campanhol Leonardo B. G. 
Published: January 2021

AbstractThis paper presents a comparison analysis involving four multifunctional grid‐tied photovoltaic (MPV) systems, divided in single‐stage and double‐stage architectures. The functionalities can be pointed out as generation/injection of active energy into the utility grid, and active power conditioning including reactive power and load unbalance compensation, as well as load harmonic currents suppression. Thus, beyond the photovoltaic systems' conventional functions, the MPV systems also contribute to improve power quality indicators. Single‐phase full‐bridge (1‐FB) inverters are used to build two grid‐tied inverter configurations. In the first, called as MPV‐FB, three 1‐FB inverters share the same DC‐bus, while in the second, named as MPV‐3FB, each of the three 1‐FB inverters operates with an individual DC‐bus. Each inverter configuration integrates the MPV system architectures with single‐stage and double‐stage, where in the single‐stage configuration the photovoltaic array is directly connected to the inverter DC‐bus, whereas in the DS one, a step‐up DC–DC converter is inserted between the photovoltaic array and the inverter DC‐bus. Under several scenarios of operation, the four MPV systems named as MPV‐FB‐SS, MPV‐FB‐DS, MPV‐3FB‐SS and MPV‐3FB‐DS, are experimentally tested to compare constructive aspects, evaluate static/dynamic performances and power quality issues, as well as capability to operate with photovoltaic array failure.
Improved Markov‐chain‐based ultra‐short‐term PV forecasting method for enhancing power system resilience
Authors: Bai Xiaoyang , Liang Liang , Zhu Xueqin 
Published: January 2021

AbstractThe awareness capability of output power for renewable resources is essential for enhancing the resilience of power systems. Photovoltaic (PV) forecasting technology is an essential technology for increasing the operation efficiency and controllable resources for power systems after extreme natural events. Conventional Markov chain (MC) methods often ignore the time characteristics and the actual distribution of the PV output power sequence when making PV forecasts. This article proposes improved MC methods of equal quantity and clustering‐based division methods. The methods can consider the interval distributions of the PV output power time series and select an hour as the time interval. As a sequence, the predicted power at the next moment can be closer to the expectation of the output power distributions. Such a method is combined with a similar day algorithm to calculate the forecast result. Case studies were conducted with one‐year operation data from a 25‐MW PV station. The results indicate that the proposed methods can effectively improve the accuracy of prediction results compared with traditional methods.
HD 344787: a true Polaris analogue?
Authors: Ripepi V. , Catanzaro G. , Molnár L. , Plachy E. , Marconi M. , Clementini G. , Molinaro R. , De Somma G. , Leccia S. , Mancino S. , Musella I. , Cusano F. , Testa V. 
Published: January 2021

Context. Classical Cepheids (DCEPs) are the most important primary indicators for the extragalactic distance scale, but they are also important objects in their own right, allowing us to place constraints on the physics of intermediate-mass stars and the pulsation theories.
Aims. We have investigated the peculiar DCEP HD 344787, which is known to exhibit the fastest positive period change of DCEPs, along with a quenching amplitude of the light variation.
Methods. We used high-resolution spectra obtained with HARPS-N at the TNG for HD 344787 and the more famous Polaris DCEP to infer their detailed chemical abundances. Results from the analysis of new time-series photometry of HD 344787 obtained by the TESS satellite are also reported.
Results. The double-mode nature of the HD344787 pulsation is confirmed by an analysis of the TESS light curve, although with rather tiny amplitudes of a few dozen millimag. This is indication that HD344787 is on the verge of quenching the pulsation. Analysis of the spectra collected with HARPS-N at the TNG reveals an almost solar abundance and no depletion of carbon and oxygen. This means that the star appears to have not gone through first dredge-up. Similar results are obtained for Polaris.
Conclusions. Polaris and HD344787 are both confirmed to be most likely at their first crossing of the instability strip. The two stars are likely at the opposite borders of the instability strip for first-overtone DCEPs with metal abundance Z = 0.008. A comparison with other DCEPs that are also thought to be at their first crossing allows us to speculate that the differences we see in the Hertzsprung-Russell diagram might be due to differences in the properties of the DCEP progenitors during the main-sequence phase.
Lactate Threshold Evaluation in Swimmers: The Importance of Age and Method
Authors: Nikitakis Ioannis S. , Toubekis Argyris G. 
Published: January 2021

AbstractThe purpose of the study was to define the most appropriate method for the calculation of the speed corresponding to lactate threshold (sLT) in male swimmers. Eight boys and eight adolescents (age: 11.4±0.5 and 15.8±0.8 years) performed 7×200-m swimming front-crawl and after drawing the speed vs. lactate curve, the sLTs were calculated using five methods: i) the intersection of two linear regression lines, ii) visual inspection, iii) D-max, iv) D-max modified, v) intersection of combined linear and exponential regression lines. All methods were compared to the speed corresponding to maximal lactate steady state (sMLSS). Two to four 30-min efforts of continuous swimming at imposed constant pace were used for sMLSS calculation. In both groups, speed of D-max modified was similar to sMLSS (children, 1.061±0.073 vs. sMLSS: 1.071±0.072 m·s−1; p>0.05; effect size: ES=0.15, small; adolescents, 1.318±0.060 vs. sMLSS: 1.284±0.047 m·s−1; p>0.05; ES=0.64, medium). In adolescents, sLT calculated by intersection of two regression lines and by visual inspection presented medium ES (0.22–0.24) and were no different to sMLSS (1.296 ± 0.051, 1.295±0.053 m·s−1, p>0.05). When testing children, D-max modified is the most appropriate method to estimate sMLSS. The intersection of the linear regression lines and visual inspection are suggested for sMLSS determination in adolescents.
Are We Exploring the Potential Role of Specialized Techniques in Muscle Hypertrophy?
Authors: Kassiano Witalo , de Vasconcelos Costa Bruna Daniella , Nunes João Pedro , Aguiar Andreo Fernando , de Salles Belmiro F. , Ribeiro Alex Silva 
Published: January 2021

AbstractSpecialized resistance training techniques (e.g., drop-set, rest-pause) are commonly used by well-trained subjects for maximizing muscle hypertrophy. Most of these techniques were designed to allow a greater training volume (i.e., total repetitions×load), due to the supposition that it elicits greater muscle mass gains. However, many studies that compared the traditional resistance training configuration with specialized techniques seek to equalize the volume between groups, making it difficult to determine the inherent hypertrophic potential of these advanced strategies, as well as, this equalization restricts part of the practical extrapolation on these findings. In this scenario, the objectives of this manuscript were 1) to present the nuance of the evidence that deals with the effectiveness of these specialized resistance training techniques and — primarily — to 2) propose possible ways to explore the hypertrophic potential of such strategies with greater ecological validity without losing the methodological rigor of controlling possible intervening variables; and thus, contributing to increasing the applicability of the findings and improving the effectiveness of hypertrophy-oriented resistance training programs.
Gastric NET Subtypes: Do We Need An Additional One?
Authors: Lock Guntram , Oelckers Michael , Clauditz Till Sebastian , Schrader Jörg 
Published: January 2021

AbstractDepending on etiology, prognosis and malignant potential, recent S2k guideline differentiates gastric neuroendocrine tumors (gNET) in 4 types with different treatment implications.We report on a 55-year-old patient with the accidental finding of a 15 mm gNET. Apart from a prolonged use of proton pump inhibitors (PPI) for 20 years as a treatment for gastroesophageal reflux disease, there were no other associations or risk factors for gNETs. Formally, this patient would have been classified as a type III gNET, implicating gastric surgery. From a pathophysiological point of view, however, the assumed prolonged gastrin hypersecretion would have justified an assignment as a type I gNET. The gNET was resected by ESD, but histology showed an R1 situation. After cessation of PPIs, there is no recurrence so far. Besides, the initially documented numerous and large gland polyps showed an impressive regression only a few weeks after cessation of PPI.This case points to a probably underestimated gap in the present gNET classification. On the basis of present literature, the therapeutic dilemma of PPI-associated gNETs is discussed. A new assignment of PPI associated gNETs as type Ib could help to overcome this dilemma.
Synthesis of Difluoromethyl-Substituted Quinazolines through Selective Difluoromethylation
Authors: Peng Yiyuan , Peng Jing , Hu Ludan , Chen Mu-Wang , Deng Zhihong 
Published: January 2021

AbstractA highly selective difluoromethylation of quinazolines has been achieved by using commercially available ethyl bromodifluoroacetate as difluorocarbene precursor, providing the corresponding difluoromethyl substituted quinazoline derivatives with up to 83% yield.
Endoscopic internal drainage and low negative-pressure endoscopic vacuum therapy for anastomotic leaks after oncologic upper gastrointestinal surgery
Authors: Jung Carlo Felix Maria , Hallit Rachel , Müller-Dornieden Annegret , Calmels Mélanie , Goere Diane , Chaput Ulriikka , Camus Marine , Gonzalez Jean Michel , Barthet Marc , Jacques Jérémie , Legros Romain , Barrioz Thierry , Kück Fabian , Seif Amir Hosseini Ali , Ghadimi Michael , Kunsch Steffen , Ellenrieder Volker , Wedi Edris , Barret Maximilien 
Published: January 2021

Abstract
Background Endoscopic internal drainage (EID) with double-pigtail stents or low negative-pressure endoscopic vacuum therapy (EVT) are treatment options for leakage after upper gastrointestinal oncologic surgery. We aimed to compare the effectiveness of these techniques.
Methods Between 2016 and 2019, patients treated with EID in five centers in France and with EVT in Göttingen, Germany were included and retrospectively analyzed using univariate analysis. Pigtail stents were changed every 4 weeks; EVT was repeated every 3–4 days until leak closure.
Results 35 EID and 27 EVT patients were included, with a median (interquartile range [IQR]) leak size of 0.75 cm (0.5–1.5). Overall treatment success was 100 % (95 % confidence interval [CI] 90 %–100 %) for EID vs. 85.2 % (95 %CI 66.3 %–95.8 %) for EVT (P = 0.03). The median (IQR) number of endoscopic procedures was 2 (2–3) vs. 3 (2–6.5; P = 0.003) and the median (IQR) treatment duration was 42 days (28–60) vs. 17 days (7.5–28; P < 0.001), for EID vs. EVT, respectively.
Conclusion EID and EVT provide high closure rates for upper gastrointestinal anastomotic leaks. EVT provides a shorter treatment duration, at the cost of a higher number of procedures.