bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insights into the physiology of Chlorella vulgaris cultivated in sweet sorghum bagasse hydrolysate for sustainable algal biomass and lipid production
Authors: Arora Neha , Philippidis George P. 
Published: March 2021

AbstractSupplementing cultivation media with exogenous carbon sources enhances biomass and lipid production in microalgae. Utilization of renewable organic carbon from agricultural residues can potentially reduce the cost of algae cultivation, while enhancing sustainability. In the present investigation a medium was developed from sweet sorghum bagasse for cultivation of Chlorella under mixotrophic conditions. Using response surface methodology, the optimal values of critical process parameters were determined, namely inoculum cell density (O.D.750) of 0.786, SSB hydrolysate content of the medium 25% v/v, and zero medium salinity, to achieve maximum lipid productivity of 120 mg/L/d. Enhanced biomass (3.44 g/L) and lipid content (40% of dry cell weight) were observed when the alga was cultivated in SSB hydrolysate under mixotrophic conditions compared to heterotrophic and photoautotrophic conditions. A time course investigation revealed distinct physiological responses in terms of cellular growth and biochemical composition of C. vulgaris cultivated in the various trophic modes. The determined carbohydrate and lipid profiles indicate that sugar addition to the cultivation medium boosts neutral lipid synthesis compared to structural lipids, suggesting that carbon flux is channeled towards triacylglycerol synthesis in the cells. Furthermore, the fatty acid profile of lipids extracted from mixotrophically grown cultures contained more saturated and monosaturated fatty acids, which are suitable for biofuel manufacturing. Scale-up studies in a photobioreactor using SSB hydrolysate achieved a biomass concentration of 2.83 g/L consisting of 34% lipids and 26% carbohydrates. These results confirmed that SSB hydrolysate is a promising feedstock for mixotrophic cultivation of Chlorella and synthesis of algal bioproducts and biofuels.
Evaluation of 16S rRNA primer sets for characterisation of microbiota in paediatric patients with autism spectrum disorder
Authors: Palkova L. , Tomova A. , Repiska G. , Babinska K. , Bokor B. , Mikula I. , Minarik G. , Ostatnikova D. , Soltys K. 
Published: March 2021

AbstractAbstract intestinal microbiota is becoming a significant marker that reflects differences between health and disease status also in terms of gut-brain axis communication. Studies show that children with autism spectrum disorder (ASD) often have a mix of gut microbes that is distinct from the neurotypical children. Various assays are being used for microbiota investigation and were considered to be universal. However, newer studies showed that protocol for preparing DNA sequencing libraries is a key factor influencing results of microbiota investigation. The choice of DNA amplification primers seems to be the crucial for the outcome of analysis. In our study, we have tested 3 primer sets to investigate differences in outcome of sequencing analysis of microbiota in children with ASD. We found out that primers detected different portion of bacteria in samples especially at phylum level; significantly higher abundance of Bacteroides and lower Firmicutes were detected using 515f/806r compared to 27f/1492r and 27f*/1495f primers. So, the question is whether a gold standard of Firmicutes/Bacteroidetes ratio is a valuable and reliable universal marker, since two primer sets towards 16S rRNA can provide opposite information. Moreover, significantly higher relative abundance of Proteobacteria was detected using 27f/1492r. The beta diversity of sample groups differed remarkably and so the number of observed bacterial genera.
Electroceutically induced subthalamic high-frequency oscillations and evoked compound activity may explain the mechanism of therapeutic stimulation in Parkinson’s disease
Authors: Ozturk Musa , Viswanathan Ashwin , Sheth Sameer A. , Ince Nuri F. 
Published: March 2021

AbstractDespite having remarkable utility in treating movement disorders, the lack of understanding of the underlying mechanisms of high-frequency deep brain stimulation (DBS) is a main challenge in choosing personalized stimulation parameters. Here we investigate the modulations in local field potentials induced by electrical stimulation of the subthalamic nucleus (STN) at therapeutic and non-therapeutic frequencies in Parkinson’s disease patients undergoing DBS surgery. We find that therapeutic high-frequency stimulation (130–180 Hz) induces high-frequency oscillations (~300 Hz, HFO) similar to those observed with pharmacological treatment. Along with HFOs, we also observed evoked compound activity (ECA) after each stimulation pulse. While ECA was observed in both therapeutic and non-therapeutic (20 Hz) stimulation, the HFOs were induced only with therapeutic frequencies, and the associated ECA were significantly more resonant. The relative degree of enhancement in the HFO power was related to the interaction of stimulation pulse with the phase of ECA. We propose that high-frequency STN-DBS tunes the neural oscillations to their healthy/treated state, similar to pharmacological treatment, and the stimulation frequency to maximize these oscillations can be inferred from the phase of ECA waveforms of individual subjects. The induced HFOs can, therefore, be utilized as a marker of successful re-calibration of the dysfunctional circuit generating PD symptoms.
Identification of core and rare species in metagenome samples based on shotgun metagenomic sequencing, Fourier transforms and spectral comparisons
Authors: Pust Marie-Madlen , Tümmler Burkhard 
Published: March 2021

Abstract
In shotgun metagenomic sequencing applications, low signal-to-noise ratios may complicate species-level differentiation of genetically similar core species and impede high-confidence detection of rare species. However, core and rare species can take pivotal roles in their habitats and should hence be studied as one entity to gain insights into the total potential of microbial communities in terms of taxonomy and functionality. Here, we offer a solution towards increased species-level specificity, decreased false discovery and omission rates of core and rare species in complex metagenomic samples by introducing the rare species identifier (raspir) tool. The python software is based on discrete Fourier transforms and spectral comparisons of biological and reference frequency signals obtained from real and ideal distributions of short DNA reads mapping towards circular reference genomes. Simulation-based testing of raspir enabled the detection of rare species with genome coverages of less than 0.2%. Species-level differentiation of rare Escherichia coli and Shigella spp., as well as the clear delineation between human Streptococcus spp. was feasible with low false discovery (1.3%) and omission rates (13%). Publicly available human placenta sequencing data were reanalysed with raspir. Raspir was unable to identify placental microbial communities, reinforcing the sterile womb paradigm.
57Fe-Enrichment effect on the composition and performance of Fe-based O2-reduction electrocatalysts
Authors: Ebner Kathrin , Ni Lingmei , Saveleva Viktoriia A. , Le Monnier Benjamin P. , Clark Adam H. , Krumeich Frank , Nachtegaal Maarten , Luterbacher Jeremy S. , Kramm Ulrike I. , Schmidt Thomas J. , Herranz Juan 
Published: March 2021

In this work, we study how the performance and composition of platinum-group metal free catalysts of the Fe–N–C type are affected upon employing 57Fe-enriched precursors in their synthesis.
Analysis and reduction of cogging torque in direct‐drive external‐rotor permanent magnet synchronous motor for belt conveyor application
Authors: Song Yongda , Zhang Zhaoyu , Yu Siyang , Zhang Fengge , Zhang Yuan 
Published: March 2021

AbstractPermanent magnet synchronous motor (PMSM) shows the great potential for use in direct drive system because of its excellent low‐speed direct‐drive capability. However, it suffers from the adverse effect of the cogging torque in comparison with the asynchronous motor. Therefore, reducing the cogging torque, especially the external‐rotor PMSM (ERPMSM) for belt conveyor application, is necessary for enhancing the stable operation and precise positioning performances of the belt conveyor.Herein, a novel tangential magnetization low‐speed high‐torque ERPMSM is proposed and analysed. Furthermore, the expression of the cogging torque of the proposed ERPMSM is derived by energy method. Based on the special structure of the ERPMSM, a new method for cogging torque reduction is introduced. The comparative FEA results for four ERPMSM models are presented to verify the accuracy and effectiveness of this method. The accuracy of the cogging torque FEA results is confirmed by a prototype. Finally, the influence of this method on ERPMSM performance is also analysed carefully in this paper.
Review of surface transient charge measurement on solid insulating materials via the Pockels technique
Authors: Zhang Bo , Xue Jianyi , Chen Xingyu , Chen Sile , Mu Haibao , Xu Yang , Zhang Guanjun 
Published: March 2021

AbstractSurface charges accumulated on solid insulating materials in electrical apparatuses and electronic devices could distort the initial electric field and severely damage the insulation performance. Accurate transient surface charge measurement is critical to determine the mechanisms of charge transport and flashover occurrence, and estimate surface insulation strength under high voltage. The measurement technique based on the Pockels electro‐optic effect is considered as the only approach for 2‐D dynamic charge distribution behaviour so far, and it has good capability to avoid original electric field distortion caused by conventional methods featured by metal probes. This paper reviews recent progress of the non‐invasive dynamic surface charge measurement systems on the Pockels technique. We focus especially on typical systems with transmitting and reflecting configurations and the frequently used fast inversion algorithms. It can be inferred that higher spatial‐temporal resolution, higher signal‐to‐noise ratio, and better compatibility for both transparent and opaque materials are the future development trends, which greatly depend on multiple technological breakthroughs at impact‐resistant electro‐optic crystals, advanced high‐speed photography and high‐performance inversion algorithms. In addition, the recent studies on transient behaviour of surface discharge, together with the present limitation and future prospects are discussed. It is expected that more ideas will be inspired in transient surface charge measurement by the Pockels technique and other relevant electro‐optic methods.
Effect of temperature on electric‐thermal properties of semi‐conductive shielding layer and insulation layer for high‐voltage cable
Authors: Wei Yanhui , Liu Mingyue , Li Xuejing , Li Guochang , Li Naiyi , Hao Chuncheng , Lei Qingquan 
Published: March 2021

AbstractA semi‐conductive shielding layer plays an important role in the uniform electric field for a high‐voltage cable. The electric‐thermal properties of the semi‐conductive layer and insulation layer directly affect the overall insulation performance of the cable. The physicochemical performances of semi‐conductive composites are firstly analysed herein. Furthermore, electric‐thermal properties of the semi‐conductive layer and insulation layer are discussed. The experimental results show that the thermal conductivity of the commercial semi‐conductive layer is about twice that of the insulation layer, owing to the effect of carbon black. The thermal expansion coefficient of the insulation layer rises from 1.86 × 10−4/K at 25°C to 3.20 × 10−4/K at 90°C. By contrast, the semi‐conductive layer begins to slowly decline at a certain temperature, and decreases significantly to 2.25 × 10−4/K at 80°C, owing to the effect of ethylene‐vinyl acetate copolymer (EVA). The electrical experiments show that the resistivity of semi‐conductive composite gradually rises with an increase in temperature, and gradually declines with an increase in the carbon black content. The dc breakdown strength of the composite structure of the semi‐conductive layer/insulation layer decreases significantly with an increase in temperature, decreasing from 307 kV/mm at 25°C to 203 kV/mm at 90°C. At four typical temperatures, the breakdown strength reaches the maximum value when the carbon black content is 25 phr. It is about 15% and 19% higher than carbon black contents of 20 and 30 phr. These findings have reference significance for high‐voltage cable breakdown fault analysis and material selection in cable design.
A method of lining seam elimination with angle adaptation and rectangular mark for road tunnel concrete lining images
Authors: Qu Zhong , Zhong Yu‐Lu , Liu Ling 
Published: March 2021

AbstractRoad Tunnels are an important part of the current road transportation infrastructure. As the main form of tunnel lining diseases, cracks are easy to interact with other areas, which seriously affects the safe operation of the tunnel. Due to the similarity of brightness and linearity between surface cracks and lining cracks, the existing crack detection algorithms can not extract cracks accurately and quickly. An algorithm of lining seam crack elimination with rectangular mark is proposed here. First, the line segments in the image are detected by the Line Segment Detector algorithm based on the coarse percolation detection of the crack. Second, the distribution directions are calculated, and cracks from the lining seams are distinguished by the adaptive threshold judgment method. Third, by using the distribution characteristics of pixels, the line segments are extended to form rectangular marks perpendicular to the direction of lining seams. Finally, the marking information is used to remove the lining joints and obtain the real surface cracks of tunnel lining. Experimental results show that the algorithm can quickly and effectively remove any shape distribution of lining seam. The algorithm fills in the blank of concrete tunnel lining surface crack detection technology.
U‐FPNDet: A one‐shot traffic object detector based on U‐shaped feature pyramid module
Authors: Ke Xiao , Li Jianping 
Published: March 2021

AbstractIn the field of automatic driving, identifying vehicles and pedestrians is the starting point of other automatic driving techniques. Using the information collected by the camera to detect traffic targets is particularly important. The main bottleneck of traffic object detection is due to the same category of targets, which may have different scales. For example, the pixel‐level of cars may range from 30 to 300 px, which will cause instability of positioning and classification. In this paper, a multi‐dimension feature pyramid is constructed in order to solve the multi‐scale problem. The feature pyramid is built by developing a U‐shaped module and using a cascade‐method. In order to verify the effectiveness of the U‐shaped module, we also designed a new one‐shot detector U‐FPNDet. The model first extracts the basic feature map by using the basic network and constructs the multi‐dimension feature pyramid. Next, a pyramid pooling module is used to get more context information from the scene. Finally, the detection network is run on each level of the pyramid to obtain the final result by NMS. By using this method, a state‐of‐the‐art performance is achieved on both detection and classification on commonly used benchmarks.
A 2 × 2 Filtering subarray element antennas using all‐resonator structures
Authors: Mahmud Rashad H. , Lancaster Michael J. 
Published: March 2021

AbstractThis study presents two novel topologies of a 2 × 2 filtering antenna subarray based on all resonator structures. The coupling matrix theory is used to extract the interresonator coupling coefficients and quality factors. The matrix parameters give a controllable bandwidth to the filtering subarrays. Rectangular waveguide cavity resonators are utilised to implement the physical layouts of the topologies. They operate at a centre frequency of 10 GHz and have a fractional bandwidth of 10% with return loss of ‐20 dB. The first topology consists of seven resonators feeding from beneath, while the second topology consists of six resonators feeding from the side. Compared to previous 2 × 2 waveguide cavity‐backed subarray antennas, the proposed 2 × 2 filtering subarrays have the advantage of having a larger bandwidth, flatter gain over the passband and larger roll‐off of the gain at the band edges. Also, when providing the feed network, the all‐resonator structure removes the need to place a bandpass filter after the antenna at the front end of a communication system. Fabrication and measurements have been performed by validating the designs.
Wideband unequal filtering power divider with high power dividing ratio based on line‐inserted method
Authors: Wang Di , Guo Xin , Wu Wen 
Published: March 2021

AbstractIn this study, a type of wideband‐filtering power divider (FPD) with high power dividing ratio (PDR) is proposed based on the line‐inserted method. The proposed wideband FPD is implemented by inserting a quarter‐wave line in front of the conventional wideband FPD. With the inserted line acting as part of each filtering branch, an additional in‐band pole is generated, and the requirement for high input impedance can be relaxed. Consequently, both the fractional bandwidth (FBW) and maximum PDR can be enhanced. To enforce the effectiveness of the inserted line, a corresponding design method for the wideband FPD is proposed and demonstrated. Initially, a wideband filter involving the inserted line is synthesized. Then, the synthesized filter is used for implementing wideband FPD using voltage transformers. Finally, the voltage transformers are successfully absorbed into the filtering branches. Examples of 4:1 and 12:1 FPDs operating at 1.8 GHz are designed and fabricated with specified FBWs of 100% and 88%. The measured PDRs are 3.9:1 and 11.2:1 with corresponding bandwidths of 103.9% and 88.3% (|S
11|< –10 dB), respectively. The proposed wideband FPD exhibits a higher PDR, wider bandwidth, equal‐ripple response, and filtering embedded compared with the conventional ones.
Study of RHO zeolite with different cations for CO2/CO separation in pressure swing adsorption
Authors: Liang Dan , Hu Yunfeng , Bao Qiang , Zhang Jian , Sun Penglai , Feng Jiawei , Xu Ming , Zhang Hongsheng 
Published: March 2021

AbstractA series of cation‐exchanged RHO zeolites, including H‐RHO, Li‐RHO, Na‐RHO, K‐RHO, Cs‐RHO, Cd‐RHO and Pb‐RHO, were prepared, and the samples were characterised by X‐ray diffraction, scanning electron microscopy, energy dispersive X‐ray spectroscopy, thermogravimetric analysis, inductive coupled plasma emission spectrometer and N2‐BET. The CO2 and CO adsorption behaviours of the samples were measured at 298 K and 0–10 bar. The Langmuir equation was used to fit adsorption isotherms to compare the separation effect of these RHO zeolites. The results show that extra‐framework cations can effectively adjust the pore size of RHO. Not only it depends on the size of the cation radius, but other factors also play an important role, such as the position of the cation. Besides, compared with CHA structure, RHO structure has better CO2/CO separation performance. In all researched cationic forms of RHO, Li‐RHO, Cd‐RHO and Pb‐RHO have excellent CO2/CO separation effects. Among them, the pore size of Cd‐RHO is significantly reduced, thereby restricting the entry of CO more effectively, ultimately leading to greater shape selectivity. Cd‐RHO not only has the highest CO2 saturated adsorption capacity and CO2 working capacity but also has relatively excellent CO2/CO selectivity, resulting in the sorbent selection parameter (S) is also the largest.
Model predictive control of a hybrid stacked multicell converter with voltage balancing and fault tolerance capability
Authors: Xu Shuai , Sun Zhenyao , Yao Chunxing , Liu Kang , Ma Guangtong 
Published: March 2021

AbstractDue to the merits of low conduction losses and superior output power quality, a hybrid stacked multicell converter (HSMC) was put forward as a competitive alternative in the medium/low‐voltage high‐efficiency applications. A nine‐level HSMC (9L‐HSMC) can be seen as a combination of a five‐level SMC (5L‐SMC) and two‐level half‐bridge, and proper modulation and control strategy are essential for the HSMC to obtain the optimal output performance. This work develops a finite control‐set model predictive control (MPC) strategy for 9L‐HSMC to balance the capacitor voltages and maintain the desired outputs, rendering the absence of the linear regulator and pulse width modulation (PWM) modulator possible. The fault‐tolerant operation can also be achieved flexibly when open‐circuit faults occur at active bidirectional switches in the 5L‐SMC bridge, and the performance is verified by simulations. Finally, experiments under several typical operating conditions are implemented to verify the effectiveness of 9L‐HSMC with the developed MPC strategy.
Analysis of multi‐constellation GNSS receiver performance utilizing 1‐st side‐lobe signal on the use of SSV for KPS satellites
Authors: Ji Gun‐Hoon , Shin Heon , Won Jong‐Hoon 
Published: March 2021

AbstractA numerical analysis is conducted for assessing the feasibility on the use of Global Navigation Satellite System (GNSS) receivers for Korea Positioning System (KPS) satellites in space service volume (SSV). KPS is planned to provide a navigation and timing service by constructing seven satellites over the Korean Peninsula, which will orbit above the GNSS constellation in SSV. The major problems caused by such orbital characteristics include reduced satellite visibility due to poor geometric diversity and weak signals, causing an increase in the user range error (URE). To address these constraints, this study considers multi‐GNSS and 1‐st side‐lobe signal utilization scenarios. More specifically, the GNSS satellite visibility, geometric dilution of precision, carrier‐to‐noise ratio, URE, and navigation error for KPS satellites in SSV are analysed through a numerical simulation. A trade‐off between visibility and received signal power as well as their effects on positioning accuracy is analysed to describe the utility of side‐lobe signals. Finally, based on numerical analysis of the simulation results, this verifies the applicability of GNSS SSV for KPS satellites through multi‐GNSS and side‐lobe utilization scenarios.