bluuebunny/crossref_metadata_2025_split huggingface dataset:
State of the art in esophagectomy: robotic assistance in the abdominal phase
Authors: de Groot Eline M. , Goense Lucas , Ruurda Jelle P. , van Hillegersberg Richard 
Published: December 2020

AbstractOver the years, robot-assisted esophagectomy gained popularity. The current literature focused mainly on robotic assistance in the thoracic phase, whereas the implementation of robotic assistance in the abdominal phase is lagging behind. Advantages of adding a robotic system to the abdominal phase include robotic stapling and the increased surgeon’s independency. In terms of short-term outcomes and lymphadenectomy, robotic assistance is at least equal to laparoscopy. Yet high quality evidence to conclude on this topic remains scarce. This review focuses on the evidence of robotic assistance in the abdominal phase of esophagectomy.
Effect of sodium bicarbonate supplementation on the renin-angiotensin system in patients with chronic kidney disease and acidosis: a randomized clinical trial
Authors: Bovée Dominique M. , Roksnoer Lodi C. W. , van Kooten Cornelis , Rotmans Joris I. , Vogt Liffert , de Borst Martin H. , Zietse Robert , Danser A. H. Jan , Hoorn Ewout J. 
Published: December 2020

Abstract
Background
Acidosis-induced kidney injury is mediated by the intrarenal renin-angiotensin system, for which urinary renin is a potential marker. Therefore, we hypothesized that sodium bicarbonate supplementation reduces urinary renin excretion in patients with chronic kidney disease (CKD) and metabolic acidosis.

Methods
Patients with CKD stage G4 and plasma bicarbonate 15–24 mmol/l were randomized to receive sodium bicarbonate (3 × 1000 mg/day, ~ 0.5 mEq/kg), sodium chloride (2 × 1,00 mg/day), or no treatment for 4 weeks (n = 15/arm). The effects on urinary renin excretion (primary outcome), other plasma and urine parameters of the renin-angiotensin system, endothelin-1, and proteinuria were analyzed.

Results
Forty-five patients were included (62 ± 15 years, eGFR 21 ± 5 ml/min/1.73m2, plasma bicarbonate 21.7 ± 3.3 mmol/l). Sodium bicarbonate supplementation increased plasma bicarbonate (20.8 to 23.8 mmol/l) and reduced urinary ammonium excretion (15 to 8 mmol/day, both P < 0.05). Furthermore, a trend towards lower plasma aldosterone (291 to 204 ng/L, P = 0.07) and potassium (5.1 to 4.8 mmol/l, P = 0.06) was observed in patients receiving sodium bicarbonate. Sodium bicarbonate did not significantly change the urinary excretion of renin, angiotensinogen, aldosterone, endothelin-1, albumin, or α1-microglobulin. Sodium chloride supplementation reduced plasma renin (166 to 122 ng/L), and increased the urinary excretions of angiotensinogen, albumin, and α1-microglobulin (all P < 0.05).

Conclusions
Despite correction of acidosis and reduction in urinary ammonium excretion, sodium bicarbonate supplementation did not improve urinary markers of the renin-angiotensin system, endothelin-1, or proteinuria. Possible explanations include bicarbonate dose, short treatment time, or the inability of urinary renin to reflect intrarenal renin-angiotensin system activity.

Graphic abstract
Understanding, Choosing, and Unifying Multilevel and Fixed Effect Approaches
Authors: Hazlett Chad , Wainstein Leonard 
Published: December 2020

AbstractWhen working with grouped data, investigators may choose between “fixed effects” models (FE) with specialized (e.g., cluster-robust) standard errors, or “multilevel models” (MLMs) employing “random effects.” We review the claims given in published works regarding this choice, then clarify how these approaches work and compare by showing that: (i) random effects employed in MLMs are simply “regularized” fixed effects; (ii) unmodified MLMs are consequently susceptible to bias—but there is a longstanding remedy; and (iii) the “default” MLM standard errors rely on narrow assumptions that can lead to undercoverage in many settings. Our review of over 100 papers using MLM in political science, education, and sociology show that these “known” concerns have been widely ignored in practice. We describe how to debias MLM’s coefficient estimates, and provide an option to more flexibly estimate their standard errors. Most illuminating, once MLMs are adjusted in these two ways the point estimate and standard error for the target coefficient are exactly equal to those of the analogous FE model with cluster-robust standard errors. For investigators working with observational data and who are interested only in inference on the target coefficient, either approach is equally appropriate and preferable to uncorrected MLM.
Urban street tree biodiversity and antidepressant prescriptions
Authors: Marselle Melissa R. , Bowler Diana E. , Watzema Jan , Eichenberg David , Kirsten Toralf , Bonn Aletta 
Published: December 2020

AbstractGrowing urbanisation is a threat to both mental health and biodiversity. Street trees are an important biodiversity component of urban greenspace, but little is known about their effects on mental health. Here, we analysed the association of street tree density and species richness with antidepressant prescribing for 9751 inhabitants of Leipzig, Germany. We examined spatial scale effects of street trees at different distances around participant’s homes, using Euclidean buffers of 100, 300, 500, and 1000 m. Employing generalised additive models, we found a lower rate of antidepressant prescriptions for people living within 100 m of higher density of street trees—although this relationship was marginally significant (p = 0.057) when confounding factors were considered. Density of street trees at further spatial distances, and species richness of street trees at any distance, were not associated with antidepressant prescriptions. However, for individuals with low socio-economic status, high density of street trees at 100 m around the home significantly reduced the probability of being prescribed antidepressants. The study suggests that unintentional daily contact to nature through street trees close to the home may reduce the risk of depression, especially for individuals in deprived groups. This has important implications for urban planning and nature-based health interventions in cities.
Elevated levels of cortisol in hair precede acute myocardial infarction
Authors: Faresjö Tomas , Strömberg Susanna , Jones Mike , Stomby Andreas , Karlsson Jan-Erik , Östgren Carl Johan , Faresjö Åshild , Theodorsson Elvar 
Published: December 2020

AbstractLong term stress exposure is typical for modern societies and might trigger different diseases. This case–control study reveals that persons who had suffered an acute myocardial infarction (AMI) had elevated cortisol concentrations in the month before the acute event. Middle-aged patients admitted to cardiology clinics with acute myocardial infarction (AMI) (n = 174) were compared to 3156 controls from a population-based cohort in southeast Sweden. The median Hair Cortisol Concentrations (HCC) for those who had suffered an AMI was 53.2 pg/mg compared to 22.2 pg/mg for the control group (p < 0.001). In bivariate analysis, higher levels of HCC were strongly (OR = 5.69) and statistically significantly associated with current AMI status. The discrimination of cases with AMI from controls remained statistically significant (OR = 5.04) even after controlling for established cardiovascular risk factors in a multivariate analysis. Middle-aged persons with acute myocardial infarction had significantly elevated cortisol levels during the month before the cardiac event. This was evident for both men and women. The biomarker cortisol concentration was independently and statistically significantly related to AMI. Chronic stress seems to be a new promising risk factor for AMI.
To tailor the conical beam by using planar superstrate
Authors: Yu Yin‐Hua , Zong Zhi‐Yuan , Wu Wen , Fang Da‐Gang 
Published: December 2020

AbstractHere, the planar superstrate is used to tailor the conical beam. In the applications of conical beam antenna, making a good balance between the wider coverage and the higher gain is always a challenge, while the planar superstrate provides the freedom of design. Through adjusting the parameters of the planar superstrate, it is possible to change the coverage range and to make the beam more flat. To verify the proposed method, some simulated results are presented and two prototypes with homogeneous dielectric slab superstrate and with patterned dielectric slab superstrate are fabricated and measured. The simulated results and the measured ones are in good agreement.
Compact fully‐canonical dual‐band bandpass filter with independently controllable bandwidths
Authors: Zhang Fan , Gao Yang , Wang Yi , Zhang Yi , Dong Yuliang , Xu Jun 
Published: December 2020

AbstractA compact four‐order fully‐canonical dual‐band bandpass filter (DBBPF) with independently controllable bandwidths is reported in this letter. The filter comprises of a pair of identical electrically end‐coupled dual‐mode open stub‐loaded resonators (OSLRs) and two different pairs of magnetically coupled λ/4 short‐circuit resonators (SCRs) that are embedded within the OSLRs for compactness. Specifically, the fundamental odd‐ and even‐mode of the OSLRs are coupled with the upper and lower pairs of λ/4 SCRs to generate the first and second passbands, respectively. In addition, the input and output ports feed the two OSLRs and provide a magnetic source‐load coupling for the filter. Owing to the special layout arrangement, the proposed filter can achieve compact size and fully‐canonical frequency response with independently controllable bandwidths, simultaneously. A four‐pole DBBPF protype centred at 2 and 3.5 GHz is designed and implemented. The measurements and the simulated ones are in good consistency.
Comprehensive analysis of a three‐phase DC–DC resonant converter with an open delta‐wye transformer using variable frequency
Authors: Santos Kristian Pessoa dos , Praça Paulo Peixoto , Oliveira Filho Hermínio Miguel , Oliveira Demercil de Souza , Barreto Luís Henrique Silva Colado , Henn Gustavo Alves de Lima 
Published: December 2020

AbstractA three‐phase soft‐switched DC–DC resonant converter with variable frequency to perform the output voltage control is proposed. The open delta‐wye connection provides a double output voltage reducing the primary current stress, turns ratio, weight and volume of high‐frequency transformer. To achieve high efficiency, an LLC resonant tank is designed so that all switches can perform zero‐voltage switching for the entire power range. In order to verify the operating principle of the converter, a design example is described, with the following converter specifications: input voltage 96 V, output voltage 380 V and a switching frequency up to 120 kHz. The feasibility and practicality of the proposed converter are confirmed by experimental results with a 1.5 kW prototype.
On the steady‐state performance of bias‐compensated LMS algorithm
Authors: Pimenta Rodrigo , Resende Leonardo , Petraglia Mariane R. , Haddad Diego B. 
Published: December 2020

AbstractAdaptive filtering algorithms are widespread today owing to their flexibility and simplicity. Due to environments in which they are normally immersed, their robustness against noise has been a topic of interest. Traditionally, in the literature it is assumed that noise is mainly active in the reference signal. Since this hypothesis is often violated in practice, recently some papers have advanced strategies to compensate the bias introduced by noisy excitation data. The contributions of this paper are twofold. The first one establishes that, in some conditions, the bias‐compensated least mean square algorithm implements an optimum estimator, in the sense that it presents the smallest variance of the set of unbiased estimators. Since the asymptotic mean‐square performance of this algorithm has not yet been investigated in detail, the second contribution adopts an energy conservation relationship to derive its theoretical steady‐state mean squared distortion. The final result is presented in a closed form, is consistent with simulations and is able to provide important guidelines to the designer.
Investigation of a hybrid converter with 16:1 wide voltage operation
Authors: Lin Bor‐Ren , Ko Mao‐Cheng 
Published: December 2020

AbstractThis study investigates a hybrid zero‐voltage switching converter for dc–dc converters on railway vehicle applications or solar PV power conversion applications. The dc–dc converters used in railway applications demand to have at least 30% to 40% input voltage variation in order to meet the international standard EN50155. However, the main nominal dc input voltages of power converters on railway applications are from 24 to 110 V. To overcome the wide voltage operation problem, a hybrid power converter with the combination of boost and resonant circuits is proposed and investigated to accomplish a wide input voltage operation (10–160 V) on railway vehicle applications. Under low‐voltage input case (Vin = 10–40 V), both boost and resonant circuits are activated to have high voltage gain. For medium‐voltage input case (Vin = 40–80 V), only full‐bridge resonant circuit is operated to achieve soft switching operation on active devices. Under high‐voltage input case (Vin = 80–160 V), the half‐bridge type resonant circuit is activated to achieve less voltage gain. The circuit performance and effectiveness are provided and evaluated by experiments.
Noise performance of textile‐based dry ECG recording electrodes
Authors: Maji Soumyajyoti , Burke Martin J. 
Published: December 2020

AbstractThis study reports attempts to characterise the noise properties of un‐gelled, textile‐based electrodes intended for use in ECG recording in wearable garments. Measurements were made using very low noise operational amplifiers and with mains power supply interference eliminated from the recorded signals so that they reflected only genuine noise. Measurements were carried out on four conductive fabric electrodes, one conductive rubber electrode and a standard self‐adhesive, gelled electrode on three male and three female subjects. Curves of the form y = K/f + C were fitted to the recorded noise spectral density functions. Coefficients obtained for the white noise spectral density ranged from 1.1 to 5.6 nV/√Hz and for the flicker (1/f) noise spectral density ranged from 8 to 80 nV√Hz.
Enhancement of sensing characteristics of Polydimethylsiloxane‐based capacitive force sensor by introducing conductive polymer to dielectric layer
Authors: Siangkhio Yasumin , Rangkasikorn Adirek , Tammarugwattana Narin , Kayunkid Navaphun , Jessadaluk Sukittaya , Rahong Sakon , Wirunchit Supamas , Nukeaw Jiti 
Published: December 2020

AbstractA capacitive force sensor is one of the electronics components used in several electronic devices and applications. An improvement of sensing characteristics of the sensor, for example sensitivity and response time, becomes an interesting research topic. The alternative approach to enhance the sensitivity and response time of polydimethylsiloxane‐based capacitive force sensors is proposed by introducing poly(3,4‐ethylenedioxythiophene) polystyrene sulphonate, a conductive polymer, into polydimethylsiloxane active layer. Two sensors using different active layers, (i) polydimethylsiloxane (conventional sensor) and (ii) poly(3,4‐ethylenedioxythiophene) polystyrene sulphonate mixed polydimethylsiloxane (modified sensor), were fabricated and characterised to reveal the sensing enhancement. Interestingly, the modified sensor shows the significant increase in the sensitivity from 0.7 to 1.14 kPa–1 (+62.86%) and the shortening response time from 1.55 to 0.43 s (−72.26%) with respect to the conventional sensor. In addition, the deterioration in elastic behaviour and the faster charge–discharge behaviour observed from the poly(3,4‐ethylenedioxythiophene) polystyrene sulphonate mixed polydimethylsiloxane film indicate the better deformation and charge transport than that from polydimethylsiloxane film. Therefore, it can be concluded that the conductive poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate additive plays the role of mechanical and electrical modification of the polydimethylsiloxane active layer leading to the enhancement in sensitivity and response time of the polydimethylsiloxane‐based capacitive force sensor.
A simplified zero‐voltage switching detection circuit and switching loss dynamic optimisation method for synchronous buck converter
Authors: Lu Sizhao , Deng Xiaoting , Li Siqi 
Published: December 2020

AbstractThis letter proposes a simplified zero‐voltage switching (ZVS) detection circuit and switching loss dynamic optimisation method. The proposed circuit and tuning method can automatically adjust the switching frequency of a synchronous buck converter to work in critical current mode to realise ZVS under a wide load range. The advantages of the proposed circuit and method are that ZVS detection and switching loss dynamic optimisation can be realised by only one ZVS detection circuit, which simplifies the detection circuit, further improves the power density and reduces the number of analogue‐to‐digital conversion channels of the digital signal processor. A prototype of the synchronous buck converter with a rated input voltage of 100 V is established to verify the effectiveness of the proposed ZVS detection circuit and switching loss dynamic optimisation method. By using the proposed detection circuit and optimisation method, the switching loss of the MOSFETs has been greatly reduced and an efficiency improvement of nearly 1% at peak output power has also been achieved.
Ground truth free retinal vessel segmentation by learning from simple pixels
Authors: Zou Beiji , Fu Hongpu , Chen Zailiang , Liu Qing 
Published: December 2020

AbstractRetinal vessel segmentation is fundamental for the automatic retinal image analysis and ocular disease screening. This paper aims to learn a ground truth free feature aggregation strategy for the vessel segmentation. Five vesselness maps modelling the vessels'profile, appearance, and shape are first generated. Together, the histogram of the local binary pattern and the green colour are extracted. In each vesselness map, the pixels with large vesselness values are regarded as simple positive samples. The pixels with small vesselness values are regarded as simple negative samples, and the pixels with mediocre values are treated as difficult pixels. The simple positive samples and simple negative samples near the difficult pixels consist of the training dataset while the rest vesselness maps together with the local binary pattern histogram, and green colour channel are used as the features to learn a strong classifier. Then, without leveraging any ground truth, multiple kernel boosting is used to combine four support vector machine kernels to learn a strong vessel model for each image. Applying this learnt model to the pixels with mediocre values in the single vesselness map, their label will be determined. Totally, five strong vessel models are learnt. Finally, pixels with the majority supports from the strong vessel models are labelled as vessel pixels. The proposed method achieves accuracy of 94.83%, sensitivity of 72.59%, and specificity of 98.11% on DRIVE dataset, and accuracy of 95.51%, sensitivity of 78.09%, and specificity of 97.56% on STARE. It outperforms the state‐of‐the‐art unsupervised methods and achieves comparable performances to the supervised methods.
Trajectory planning and tracking control of unmanned ground vehicle leading by motion virtual leader on expressway
Authors: Cao Fugui , Jiang Haobin 
Published: December 2020

AbstractFormation driving can effectively solve the problem of driving efficiency and safety of unmanned ground vehicles (UGVs) on expressways. This study introduces a trajectory planning and tracking control method from initial position to its motion virtual leader in formation driving. In order to reduce the disturbance to the surrounding UGVs, trajectory planning is divided into two stages: steady speed tracking stage and parameter value matching stage. A tracking controller combined with a trajectory planner is designed to track the reference trajectory accurately. To ensure calculation speed and accuracy, a nonlinear model‐predictive control model is used in the trajectory planner, and the tracking controller is based on the linear time‐varying model‐predictive control (LTV MPC) model. Simulations are carried out with Carsim and MATLAB/Simulink, and the simulation results and comparative analysis show that the planned trajectory is feasible and can effectively avoid static and moving obstacles. Compared with the Stanley controller, the LTV MPC controller has the advantages of faster convergence speed, better stability and accurately tracking.
The pattern recognition of multisource partial discharge in transformers based on parallel feature domain
Authors: Xu Yanchun , Xia Haiting , Xie Shasha , Lu Mi 
Published: December 2020

AbstractThe traditional diagnosis methods for the multisource partial discharge in transformer have several problems, such as the poor effect of signal separation, the inaccuracy of the extracted signal features and the over fitting of the neural network algorithm used for pattern recognition. In order to solve the above problems, the improved algorithm of stacked auto‐encoder is adopted to extract the adaptive features of partial discharge one dimensional defect signals in time domain and two dimensional defect signal in time frequency domain, and a parallel feature space combining the features in time domain with that the time frequency domain is constructed. For the first time, the transformed L1 norm is utilized as the regular term of the loss function which is solved by the proximally guided stochastic subgradient in the improved auto‐encoder. The trained neural network model can be utilized for pattern recognition of the different multisource partial discharge signals. The results show that the proposed method has a higher recognition rate for the different multisource partial discharge defects than that in the traditional method, and alleviates the problem of over fitting to a certain extent.