bluuebunny/crossref_metadata_2025 huggingface dataset:
Technology and application of operation control of DC distribution network
Authors: Tan Kuo , Wu Hai , Hu Guo , Huang Qi
Published: April 2021

DC distribution network consists of distributed generation, energy storage, load and AC distribution network, With the rapid development of DC distribution network and the increasing proportion of DC load, the operation mode of DC distribution network is more flexible. Different from the traditional AC distribution network, the traditional AC distribution network has a single operation mode, while the DC distribution network can operate in both parallel mode and island mode. Therefore, a control method suitable for different operation modes of DC distribution network is urgently needed. In this paper, a control method about loop closing and loop opening of DC distribution network is proposed. When receiving the command of loop closing or loop opening from the master station or local monitoring system, the loop closing control is judged by the switch state, fault state and operation state of converter. It solves the problem that the traditional AC distribution network control strategy is not applicable in DC distribution network, it realizes the smooth switching of DC distribution network closed loop operation and opened loop operation. This method has been used in the DC coordinated control device and successfully applied in the national key research and development plan of Suzhou active distribution network.
Wireless Power and Signal Transmission Based on Time-sharing Multiplexing for WPT System
Authors: Wu Xiaorui , Gong Wenlan , Xiao Jing , Chen Shaonan , Wu Ning
Published: April 2021

In wireless power transfer (WPT) systems, wireless transmission of signals is particularly important for some practical applications. An effective approach of signal and energy synchronous transmission based on time-sharing multiplexing of the same coupled coil is proposed in this paper. Using the same coupled coil, the signal transmission is carried on when interruption of power transmission happens. To realize the proposed method, the relationship between power transmission time and signal transmission time is provided to obtain the optimal transmission process of the power and signal. Besides, the power transmission efficiency (PTE) and the signal transmission rate (STR) are analyzed. Finally, the effectiveness of the proposed method is verified by the experiment.
Monitoring Method of Transmission Line Breaking Prevention Based on Deep Learning
Authors: Yan Jiang , Qiang Li , Guanyao Wang , Ben Wang , Wei Deng
Published: April 2021

With the rapid development of the national economy, the national power consumption level continues to increase, which puts forward higher requirements on the power supply guarantee capacity of the power grid system. The distribution range of the transmission line is wide and densely, most lines are exposed to the unguarded field without any shielding or protective measures, which are vulnerable to man-made destruction or natural disasters. Therefore, it is very important for the early monitoring and prevention of the external force breaking of the transmission lines. The method for preventing external breakage of transmission lines based on deep learning proposed in this paper utilizes the video data collected by the cameras erected on the transmission line roads to perform feature extraction and learning through 3D CNN and LSTM networks, and obtains a monitoring model for external breakage prevention of transmission lines. The model was tested on public data sets and verified that it has a good performance in the field of transmission lines against external damage. The method in this paper makes full use of the existing video acquisition equipment, and the process does not require human intervention, which greatly reduces the cost of line monitoring and the hidden dangers of accidents.
Adaptive Voltage Control of Distribution Network with High Proportion PV
Authors: Ma Junchao , Huang Xiaoming , Lou Boliang , Xiao Xiulin , Fan Yinlong , Zhou Dan
Published: April 2021

With the increase of grid-connected PV capacity, voltage regulation at point of common coupling by controlling the reactive power injected into the grid is available. This paper presents an adaptive voltage control strategy for distribution network with high proportion PV system. The PI gain of the voltage controller is automatically adjusted by the extremum seeking algorithm to dynamically respond to the changes of the network. The PI gains are updated online through the minimization of a cost function, which represents the voltage controller performance. Finally, a distribution network model of 5 MW photovoltaic power generation system is built in MATLAB / Simulink to verify the effectiveness of the proposed control strategy.
Distribution network planning considering the integration of demand-side resources
Authors: Li Xiaowei , Tao Yigang , Li Min , Chen Chu , Li Rongyao , Liu Shuqi , Gu Jie
Published: April 2021

Maximizing the potential value of demand-side resources in terms of network reliability and economy is a considerable challenge because of their time-varying and potentially complex operational characteristics. It is urgent to take the interactive relationship between supply and demand side into consideration to improve the efficiency and practicability of the distribution network planning and enhance the utilization of existing equipment. In this paper, the uncertainty of DG output and the load is first modelled, and the seasonal label information is added to the model to generate the planning-oriented scenarios of DG output and the load. Considering the integration of demand-side resources, a bi-level optimal planning model is established to minimize the annual total cost of the distribution network. The proposed model is tested on the IEEE 33-node distribution system to illustrate its feasibility and validity in distribution network planning with consideration of the integration of demand-side resources.
Random vibration analysis of an offshore flexible direct current converter valve
Authors: Lv Wei , Mao Zhiyun , Zhang Lihong
Published: April 2021

With the rapid development of the direct-current grid technology and construction, the flexible direct-current transmission technology has been widely used in many aspects, such as long-distance large-capacity power transmissions, offshore platforms and island power supplies. The offshore flexible direct current converter valve will encounter a variety of unfavorable loads during the marine transportation and the long-term operation on the sea. The safety requirements of the offshore flexible direct current converter valve are higher as a result. Based on the structural characteristics of the converter valve, the converter valve is calculated by finite element method. Under two working conditions of the marine transportation and the long-term operation on the sea, this paper carries out modal analysis and random vibration analysis of the converter valve tower respectively. This paper gives the unfavorable position of the force from the calculation results, and provides a reference for the design and selection of the flexible direct current converter valve to meet the needs of the offshore converter station’s construction.
Study on icing and its trip laws of transmission lines in Shanxi Power Grid
Authors: Zhao Bin , Zhang Li-chun , Yang Jia-lun , Ji Kun-peng
Published: April 2021

Overhead transmission lines are important carriers of electric energy transmission. Their icing, galloping and shedding in winter and spring seriously threatened the safe operation of Shanxi power grid. Especially in the recent years, compact lines and double circuit lines on the same tower, typical types of overhead transmission lines in Shanxi Power Grid, were affected by frequent trips induced by icing, galloping, and shedding appeared in their conductors repeatedly, which seriously reduced the capacity of power energy transmission in Shanxi and caused trillions of power load losses. Through detailed investigation and analysis of the characteristics and historical fault cases of compact lines and double circuit lines on the same tower in Shanxi Power Grid, the key causes and main laws of two types of lines in Shanxi Power Grid are clarified, which could provide support for the follow-up line anti-ice technical transformation and capacity improvement.
Long-term load combination forecasting method considering the periodicity and trend of data
Authors: Jingying Yang , Minglei Jiang , Xin Li , Xin She , Haokuo Xin , Lin Zhou , Chang Liu
Published: April 2021

In order to solve the problems of insufficient accuracy of long-term power load forecasting and poor applicability of the model, this paper considers the coupling of a number of macro indicators, such as regional economic development and social development indicators, with the time series data of regional power load. BP neural network and Autoregressive integrated moving average model (ARIMA) are used to integrate and improve the forecasting model, so as to improve the trend forecasting ability of annual load forecasting model. The non parametric function method is used to forecast the periodic load data in the monthly load data, the annual load forecast is combined with the monthly load forecast to improve the overall forecasting accuracy of the model. Finally, through the comparison of grey prediction and other models and the verification of MAPE error analysis method, the prediction accuracy of the model method considering the combination of data periodicity and trend is significantly improved, which is suitable for the long-term prediction of regional power load.
Research on Construction Method of Micropiles in Transmission Lines
Authors: Zhu Zhaoqing , Ding Shijun , Man Yin , Yang Wenzhi
Published: April 2021

With the development of the national economy, the available land for industrial construction is becoming more and more restricted, and the paths of transmission lines and transformation projects mostly pass through regions with complex geological conditions such as mountains. The drilling micropiles foundation of transmission lines can be widely used in mountainous areas because of its strong adaptability. This paper mainly introduces the characteristics of micropiles foundation construction method and puts forward the construction process and operation points.
Research on Self-exciting Air-core Pulsed Alternator Considering Armature Reaction
Authors: Li Wenchao , Zhang Ying , Liu Zehui , Luo Danni , Wang Youlong , Sun Yaohong
Published: April 2021

Compared with the traditional synchronous generator with iron core structure, air-core pulse alternator usually adopts self-excitation to establish a higher field current to meet its demand for high flux density. In this paper, the topology of the self-exciting rectifier is determined to be the full bridge rectifier by discussing the respective application scope of the full bridge and the half wave rectifier. Considering the armature reaction, the self-excitation process and the coupling relationship between the field winding and the armature winding are analyzed. According to the commutation overlap angle, the equivalent circuits of different states are carried out, and the instantaneous expressions of field current and armature current are deduced, which lays a foundation for the following phase control research.
Research on Basic Characteristics and Bidding Strategy of Thermal Power Units in Fujian Spot Market
Authors: Song Yuhui , Pan Zhanhua , Chen Baike , Jing Zhaoxia
Published: April 2021

In the electricity market environment, thermal power units have changed from the executors of power production under the monopoly mechanism to the decision-makers of production and operation under the competitive environment. The merits and demerits of bidding schemes for thermal power units are directly related to self-interest of themselves. The bidding decisions of power plants are not only affected by economic factors, but also by technical factors peculiar to the power system and the electric generator. In recent years, research on bidding strategies of thermal power units based on the power market environment has been paid more and more attention in the field of electric market. This paper first introduces the basic peak regulation and frequency modulation technical characteristics of thermal power units and cost calculation. Then, from the angle of quotation, paper analyzes characteristics of quotation mechanism of units in Fujian Electric Power day-ahead, real-time and peak regulation auxiliary service market. Furthermore, the research status of bidding strategies of thermal power units participating in electricity market at home and abroad in cost analysis, market clearing price prediction, game theory and so on are summarized. Finally, the bidding strategy for units in Fujian Spot Market is put forward.
Research on battery capacity reliability of intelligent power supply equipment
Authors: Dai Zikuo , Xu Yan , Shi Kejian , You Yang , Li Bingxin
Published: April 2021

Battery is not only the power source or emergency power supply for many ships, but also the essential emergency power supply for train command and dispatching, post and telecommunication, bank operation, etc. The capacity of battery will be directly related to the normal operation of ship train dispatching, post and telecommunication and bank operation. At the same time, the battery is also the last guarantee for the safe and reliable power supply of intelligent power supply equipment, so it is necessary to study the reliability of battery capacity
Study on enhanced bioremediation effect of oil-bearing dredging sediment
Authors: Chao Lei , Mo Xiaoyun , Meng Jia , Li Yafeng
Published: April 2021

To solve the problem of difficult treatment of oil-bearing dredging sediment, the effects of three methods of microbial remediation, phytoremediation and combined bioremediation on the treatment of oily river dredging sediments were compared and studied, and the influence factors of microbial remediation were explored through static bacteria-fling tests. The results showed that the combined remediation method was better than the single biological method in treating bottom mud. The oil content of the treated sediment was 1.21g/kg, and the removal rate was 95.31%; the organic matter of the treated sediment was 72.30g/kg, and the degradation rate was 37.33. %, which can meet the requirements in the “Control Standards of Pollutants in Sludge for Agricultural Use (GB4284–2018)” and can be used for agricultural purposes.
The mathematical model of gas flowing in porous medium based on the homogenization method
Authors: Xiong Wei
Published: April 2021

Considered the characteristics of porous medium in the coal seam and goaf, in order to reflect the accurately influence of various porous media against the gas flow, the mathematical model of discrete multi-scale network and macroscopic flow, CFCM (Coal-Fracture-Cavity-Model), was presented. The porous medium is classified into coal matrix, fracture and hole systems based on the size, and the coal matrix system includes micro fractures and micro-porous. The coal matrix system and fracture system can be regarded as diffusion and percolation areas; hole system can be regarded as a free-flowing area. The computation model of flow field in micro-scale, small-scale and large-scale are obtained according the Fick’s diffusion law, Darcy’s permeability law and Forchheimer generalized Darcy law respectively, the homogenization method is used to analyse the mathematical model by scale upgrading and the equivalent Darcy’s fluid equation of porous medium is got to describe the characteristics of the medium in the flow field accurately. An example calculated shows that the coal matrix and fracture systems are the most influential factors of the flow field in goaf and the two systems above would prevent the diffusion of airflow. The study validates the correctness of the classification method and the model of flow equation.
Experimental study on soot characteristics of laminar co-flow ethylene diffused flame under air atmosphere
Authors: Xu Jing , Jiang Ping , Liang Xiaoling , Tian Ruijiao
Published: April 2021

The morphological characteristics of ethylene flame under different working conditions were photographed and analyzed by CCD camera, the temperature distribution at different positions of flame was measured and analyzed by the thermocouple, and the characteristics of soot in ethylene diffusing flame under different airflow rates were studied by means of SiC fiber sampling and subsequent TEM image analysis. The results showed that: (1) when the airflow was unchanged, the flame height increased with the increase of ethylene flow, and the flame height changed with the increase of ethylene flow in a linear relationship. When the ethylene flow increased from 120 mL/min to 180 mL/min, the flame height increased by about 60%. The flame height increased slightly with the increase in air flow. (2) The flame edge temperature was always greater than the central temperature of the corresponding height. Under the same working condition, the average temperature was 87.5 °C higher. (3) Along the flame axis, soot particles follow the process of nucleation, growth, condensation, agglomeration, and oxidation, and the four processes coexist. Once the flow rate of ethylene is determined, the generation of soot in each stage will lag when the flow rate of air increases.
Influence Factors and Correction coefficient for Energy Consumption of Electric Vehicles
Authors: Li Xiao , Gao Runze , Yu Haitao
Published: April 2021

With the application of electric vehicles, the problem of energy consumption has been widely concerned. Fixed operating conditions energy consumption in the laboratory environment was used for vehicle identification, which made big difference from the actual situation. The paper was based on the actual operation data of the vehicles. The influence factors of energy consumption have been put forward through theoretical analysis. The correction factor was calculated by big data analysis and statistical fitting. The actual energy consumption of electric vehicles can be more accurately estimated through the research results.
Efficient catalytic reduction of 4-nitrophenol by Cu1.96S/NSC hybrid material derived from metal-organic framework
Authors: Wang Dongsheng , Zhang Chengxin , Zeng Fanming , Hu Xiaoli , Li Chun , Su Zhongmin
Published: April 2021

Designing carbon-based non-precious metal hybrid materials to replace precious metal catalysts to solve environmental pollution problems is a hot topic of research at this stage. In this work, a dual ligand Cu-MOF was synthesized by the solvothermal method and using Cu-MOF as a sacrificial template further vulcanized to obtain Cu1.96S/NSC hybrid material. The morphology and composition of Cu1.96S/NSC hybrid material were investigated by scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), x-ray diffraction (XRD), nitrogen adsorption-desorption, and x-ray photoelectron spectroscopy (XPS) in detail. Cu1.96S/NSC has excellent catalytic activity in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) showing the reaction rate constant k=0.0242 s-1, which can reach nearly 100% conversion rate in 3 min. Finally, the mechanism of Cu1.96S/NSC hybrid material’s efficient catalytic reduction of 4-NP was deeply explored.
A non-metallic additive for diamond-wire-sawn multi-crystalline silicon texturing
Authors: Wang He , Zhou Chunlan , Wang Wenjing
Published: April 2021

Diamond-wire-sawn (DWS) technology has been widely used in the photovoltaic industry. When using the HF/HNO3/H2O acid etching solution for texturing of DWS multi-crystalline silicon(mc-Si), the aid of additive is required to improve the reactivity of the mc-Si surface in the acid texturing solution. It also needs to enhance the nucleation and uniform growth of the texturing surface. This paper proposes a non-metallic additive for DWS mc-Si texturing. Sodium polyacrylate is added to the HF/HNO3/H2O acid etching solution to reduce the reflectance of DWS mc-Si and improve surface morphology. Compared to the textured wafers without additive, the surface of the wafers using this method is uniformly distributed with pits whose size is 0.5 μm×1 μm. And the weighted average reflectance of the textured wafers can be reduced from 33.32% to 23.9% in the wavelength range of 350–1100 nm, with the lowest reflectance of 19.8% reached at 950 nm. It shows a promising application prospect.
Operation Rule of Steam Ejector and Influence Analysis of Ejection Position
Authors: Jinhui Zhao , Yongbo Xia , Yufeng Wang , Tao Liu , Lijun Zhang
Published: April 2021

In order to analyze the operation rule of steam ejector used in sewage treatment field, this paper established the mathematical model of steam ejector, simulated the internal flow state, analyzed the influence rule of external parameters on the performance of steam ejector, and analyzed the influence rule of ejector position on the water production ratio of steam ejector multi-effect evaporation desalination system. The research results show that under the same steam ejector structure, as the pressure of the working steam increases, the mixing and disturbance of the working steam and the ejected steam become more intense, and the diamond shock wave structure increases. As the pressure of the ejected steam increases, the momentum exchange effect of the shear blending of working steam and ejected steam is accelerated, and the speed increase rate becomes larger, and the diamond shock wave structure gradually gathers toward the nozzle. As the pressure rise of the ejected steam inlet and outlet increases, the backflow phenomenon near the wall in the mixing chamber becomes more serious, and the diamond shock wave structure is reduced. With the forward movement of the ejector position of the thermal steam compressor, the pressure of the ejected steam increases, and the water production ratio of the steam ejector multi-effect evaporation seawater desalination system shows a downward trend. Therefore, choosing appropriate working condition parameters can effectively improve the working performance of steam ejector and improve its operating efficiency in the field of sewage treatment.
Research progress on adsorption application of attapulgite by visualization analysis in recent 30 years
Authors: Zhang Mengxin , Huang Hui , Li Ru , Zhang Jia
Published: April 2021

Objective: Objective: attapulgite, as a kind of natural adsorption material with abundant reserves and friendly environment, has been widely concerned by mineral, environment, materials, chemistry and other disciplines.CiteSpace software was used to analyze the literatures about attapulgite adsorption application from 1987 to 2021 in CNKI database. Results: the amount of literature about attapulgite adsorption application showed an increasing trend year by year; The key words were: modification, kinetics, etc.; The core authors were: Shuang Ren, Mengfei Zhang, Bin Shuai etc.; The organization with the largest number of papers was the northwest Key Laboratory of plant nutrition and agricultural environment, Ministry of agriculture. Conclusion: this paper deeply analyzes the development status and current hot spots of attapulgite in the field of adsorption application research, and forecasts the future development trend, in order to promote the efficient utilization of attapulgite and provide reference for the next research.
Structural Dynamic Modification Based on Combined Approximations Method
Authors: Jin Yuchen , Yang Xiaochen , Feng Rui , Zuo Wenjie , Guo Guikai
Published: April 2021

Structural dynamic modification plays an important role in structural dynamic design. This paper presents an algorithm for dynamic modification of the structure, which is based on the Combined Approximations (CA) approach, sensitivity analysis, Taylor series expansion and the least square method. The feasibility of the algorithm is verified by a numerical example and the results show that the algorithm is accurate enough and easy to be implemented.
The rules of temporal and spatial migration of Cd content
Authors: Yang Dongfang , Jiang Hexin , Zhang Longlei , Wang Qi , Li Haixia
Published: April 2021

According to the survey dataset on the waters of Jiaozhou Bay from 1984 to 1988, this paper discusses the data of Cd content each year. From the perspectives of content size, horizontal distribution, vertical distribution, seasonal distribution, regional distribution, structural distribution and tendency distribution, it studies the source, water quality, distribution and migration conditions of Cd content in the waters of Jiaozhou Bay. On the scale of space, 21 migration rules have been gotten during the spatial and temporal variation process of Cd content in the waters of Jiaozhou Bay.
Study on wellbore instability mechanism and drilling fluid optimization of Yingsha block in southwest Tarim Basin
Authors: Sheng Yong , Ye Yan , Zhou Zhishi , Zhou Guangxu , Luo Wei , Ren Lingling , Song Hanxuan
Published: April 2021

The southwest area of Tarim has good potential for exploration and development, but the geological conditions of Yingsha block are complicated and complex conditions occurred frequently in drilling operations. There were 11 times lost circulation, which ranged from N2a to E1a and the lithology ranged from mudstone and sand-mudstone interbeds to gypsum rock, and the drilling cycle is up to 719 days, which seriously restricts the exploration and development of oil and gas resources. In this paper, the rock mineral composition and physical and chemical characteristic profiles of the whole well have been established for the well drilled in this area. The characteristic profiles show that quartz (21.4%~57.4%) and clay minerals (17%~44.9%) are the main layers in the lower strata (5069 m-7015 m) drilled in Yingsha. The clay minerals are dominated by illite (58%~85.75%) without smectite. The highest proportion of illite/smectite formation is 25%, the highest expansion rate is 23.87%, and the lowest recovery rate is 3%. Therefore, the stratum has strong hydration and dispersion characteristics. The average porosity of 4064 m-6666.5 m is 1.86%-6%, and the formation cracks are well developed. The wellbore instability mechanism in Yingsha is the good physical property of the sandstone, the development of cracks and micro-cracks in the lower strata, the broken strata, and the strong hydration and dispersion ability. The performance evaluation of KCL-Polysulfonate drilling fluid used in Yingsha shows that the recovery rate increases to more than 80% when the amount of KCL is 7–10%. With the introduction of paraffin nano-emulsion, the filtration loss is reduced by 30%, and the inhibition and plugging performance of drilling fluid is further improved.
Analysis and Study on Classroom Air Quality in Post-epidemic Era
Authors: Wen ZhiMei
Published: April 2021

Taking No.21 Teaching Building of a university in Dezhou as the test site, this paper investigates the interviewees’ (college students) satisfaction with the thermal environment of the classroom and the reasons for dissatisfaction, learning efficiency and influencing factors, and analyzes the influence of users’ personalized characteristics on the thermal comfort of the interviewees by means of measurement and investigation methods. During the field survey and investigation, it is found that the classroom environment can guarantee the learning efficiency of the vast majority of interviewees, but the air quality needs to be improved. This paper aims to provide some reference for the design of indoor space and environment of university classrooms in the post-epidemic era.
Establishment of chromium detecting kit and its application in sea water and seafood
Authors: Shi Cuijuan , Gao Xiujun , Xie Qiuju , Kan Guangfeng
Published: April 2021

Chromium is one of main pollution in sea water, and the establishment of detecting kit is the research hot topic. In this study, immunized mice were obtained by immunogen Cr3+-EDTA-BSA, and hybridoma strains that secrete Cr3+-EDTA monoclonal antibody were selected. Cr3+-EDTA mAb were prepared with in vivo method. Then, Cr-kit for measurement of chromium was developed, and its application was executed in sea water and seafood. Two hybridoma strains of A321 and A424 were screened. The Cr-kit standard curve of the linear range was 1.0—512 μg/L, and limit of detection was 1.0 μg/L. The average recovery rates Cr spiked in samples of sea water, clam and shrimp were 102.62%, 94.69% and 96.29%, which were accordance with the results of ICP-AES. Totally, Cr-kit was successfully developed and behaved broad application potential in sea water and seafood.
Substanzen zur Flüssigkeitstherapie und Outcome – ein Update
Authors: Grünewald Matthias , Heringlake Matthias
Published: April 2021

Die Flüssigkeitstherapie zählt zu den häufigsten medizinischen Maßnahmen mit dem Ziel, den Flüssigkeitshaushalt zu normalisieren. Ein entscheidendes Kriterium für die Effizienz des Flüssigkeits- oder Volumenersatzes ist die Funktionsfähigkeit der Glykokalyx, einer dünnen endothelialen Glykoproteinschicht. Sie ist ein wesentlicher Faktor für den Flüssigkeitsaustausch und -transport zwischen Gefäßsystem und Gewebe. Das erst jüngst beschriebene revidierte Starling-Prinzip erweitert das Verständnis erheblich. Aus klinischer Sicht sollte die Flüssigkeitstherapie eine zeitnahe Euvolämie anstreben, ohne relevante Nebenwirkungen zu induzieren. Es stehen hierfür sowohl kristalloide als auch natürliche oder synthetische kolloidale Lösungen zur Verfügung. Bei den kristalloiden Lösungen scheinen die sog. balancierten Vollelektrolytlösungen mit weniger Nebenwirkungen assoziiert zu sein. Kolloide Lösungen haben bei intakter Gefäßbarriere einen höheren Volumeneffekt, besitzen aber
teilweise erhebliche Nebenwirkungen. Einige synthetische Kolloide dürfen daher nicht mehr bei kritisch kranken Patienten eingesetzt werden. Im Gegensatz dazu führt die Gabe von Humanalbumin 20% bei kardiovaskulär erkrankten, hypalbuminämen Patienten zu einer Reduktion von Nierenfunktionsstörungen und scheint auch mit weiteren klinischen Vorteilen assoziiert zu sein. Inwieweit zukünftige, individualisierte Therapieansätze das Outcome beeinflussen können, bleibt abzuwarten.
Sectio caesarea unter Gitelman-Syndrom
Authors: Rombach Stephan , Benner Alexander , Schick Martin Alexander
Published: April 2021

Das Gitelman-Syndrom ist ein seltenes hereditäres Salzverlustsyndrom, das den Anästhesiologen vor eine Herausforderung stellt – insbesondere dann, wenn die Symptomatik durch eine Schwangerschaft zusätzlich verstärkt wird. Dieser Beitrag zeigt anhand eines Fallbeispiels die Besonderheiten im geburtshilflichen Kontext und das anästhesiologische Vorgehen bei einer Sectio caesarea unter Gitelman-Syndrom.
Use of fully covered self-expanding metal biliary stents for managing endoscopic biliary sphincterotomy related bleeding
Authors: Bilal Mohammad , Chandnani Madhuri , McDonald Nicholas M. , Miller Corey S. , Saperia James , Wadhwa Vaibhav , Singh Shailendra , Cohen Jonah M. , Berzin Tyler M. , Sawhney Mandeep S. , Pleskow Douglas K.
Published: April 2021

Background and study aims Endoscopic biliary sphincterotomy (EBS) related-bleeding is a common adverse event related to endoscopic retrograde cholangiopancreatography (ERCP). Traditionally, endoscopic modalities such as epinephrine injection, cauterization, and balloon tamponade have been used for management. Recently, use of a fully covered self-expandable metal stent (FCSEMS) to manage EBS-related bleeding has gained popularity. However, data regarding its use are limited to small case series. Therefore, we aimed to evaluate the safety and efficacy of FCSEMS placement for the treatment of EBS-related bleeding.

Patients and methods All patients referred to our center from October 2014 to November 2019 who had an FCSEMS placed for EBS-related bleeding were included. FCSEMS was placed either for primary control of bleeding or after failure of other traditional endoscopic hemostasis techniques at the discretion of the endoscopist. Data was collected regarding patient demographics, procedural characteristics, clinical and technical success rates of FCSEMS, as well as adverse events.

Results A total of 97 patients underwent placement of FCSEMS for EBS-related bleeding, of which 76.3 % had immediate bleeding and 23.7 % had delayed bleeding. Mean age was 67.2 years and 47.4 % were males. Seven patients who had immediate EBS-related bleeding at index ERCP underwent other endoscopic therapies prior to placement of FCSEMS for rebleeding. The technical success rate for FCSEMS placement was 100 % and the rebleeding rate was 6.2 %. Four patients with FCSEMS placement developed pancreatitis and four had stent migration.

Conclusions Our findings suggest that FCSEMS is a highly effective treatment modality for managing EBS-related bleeding and has an acceptable safety profile.
Induktion einer strickleiterartigen Narbe an der Wange einer 28-jährigen Frau nach Laserung eines Naevus araneus mittels KTP-Laser
Authors: Lehmann L. , Hofmann S. , Dirschka T. , Lehmann P.
Published: April 2021

Die 28-jährige Patientin stellte sich zur Behandlung einer kosmetisch störenden Gefäßläsion an der Wange vor. Es wurde eine Lasertherapie vorgeschlagen und vereinbart. Es entstanden unmittelbar nach der Laserbehandlung Schmerzen und eine Rötung; später eine entstellende Narbe.

Die Gutachter der Gutachterkommission bei der Ärztekammer Nordrhein beurteilten die Behandlung als fehlerhaft.

Laserbehandlungen zählen insgesamt zu den risikoreicheren Therapien in der Dermatologie. Häufiger als andere Behandlungsoptionen beurteilen die Begutachter die Behandlungen als fehlerhaft.
Enhancing bypass starch in cassava chip to sustain growth in goat
Authors: Renuh S. , Candyrine S. C. L. , Paengkoum P. , Goh Y. M. , Sazili A. Q. , Liang J. B.
Published: April 2021

Context Reducing fermentation rate to enhance bypass starch through simple treatment can be a viable way to better utilise tropical high-energy starch-rich feed such as cassava chip for ruminant production. Combining tannic acid and temperature treatment could possibly achieve the above. However, the optimal combination level of the above two factors and the efficacy of such treatment need to be tested. Aims The aims of the present study were to determine an effective tannic acid × temperature treatment to reduce degradation of starch in cassava chip and to evaluate its efficacy to enhance growth, using goats as study model. Method The study consisted of two experiments. In the first, cassava chip treated with four tannic acid levels × two temperatures combinations were evaluated using in sacco procedure to determine the effectiveness of the treatments in reducing the degradation of cassava chip. This was followed by an in vivo feeding trial to evaluate the efficacy of the treated cassava chip, on the basis of the most effective treatment from Experiment 1 on growth and digestion parameter in goats. Key results Results of the first experiment showed that the most effective treatment to reduce degradation of cassava chip was by treating it with 7.5% tannic acid at 120°C. Results of the in vivo trial showed that feeding the goats 30% treated cassava chip in the diet did not affect their daily feed intake, average daily gain and feed conversion ratio compared with their counterparts that were fed the control diet made up of similar proportion of untreated cassava chip. Treated cassava also did not affect rumen pH, volatile fatty acid (except acetate) production, rumen microbial population (except methanogen) and apparent DM, crude protein and starch digestibility. However, there was a drastic reduction in the estimated total and digestible starch intakes, apparently due to the low starch content in the treatment diet. Conclusions Treating cassava chip with 7.5% tannic acid and 120°C reduced in sacco effective degradation by 23% compared with the control. However, this beneficial effect was not reflected in the in vivo trial, which needs further evaluations. Implications The present study addressed a practical approach and its challenges to reduce degradation rate of high-energy feed to enhance bypass starch in ruminant nutrition.
CD4+T cells require Ikaros to inhibit their differentiation toward a pathogenic cell fate
Authors: Bernardi Chiara , Maurer Gaëtan , Ye Tao , Marchal Patricia , Jost Bernard , Wissler Manuela , Maurer Ulrich , Kastner Philippe , Chan Susan , Charvet Céline
Published: April 2021

Significance

The production of proinflammatory cytokines, particularly granulocyte-macrophage colony-stimulating factor, by CD4+T cells is a key process for amplifying immune responses but can also lead to harmful tissue damage in pathologies like multiple sclerosis and Covid-19. Correctly controlling the expression of proinflammatory cytokines is therefore of major interest. However, the pathogenic signature of CD4+T cells relies on a transcriptional program that is thus far poorly understood. Here, we identified the transcription factor Ikaros as an essential transcriptional repressor of proinflammatory cytokine gene expression. Our work identifies a critical molecular pathway regulating the pathogenic program of CD4+T cells and brings new perspectives for potential therapies of autoimmune and inflammatory diseases.
Pittosporum undulatum (Australian cheesewood).
Authors: Rojas-Sandoval Julissa
Published: April 2021

A datasheet on Pittosporum undulatum covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Bauhinia monandra (Napoleon's plume).
Authors: Rojas-Sandoval Julissa , Acevedo-Rodríguez Pedro
Published: April 2021

A datasheet on Bauhinia monandra covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Synthesis of graphene–aluminium matrix nanocomposites: Mechanical and tribological properties
Authors: Chak Vineet , Chattopadhyay Himadri
Published: April 2021

The study reports development of graphene nanoplatelets reinforced aluminium-matrix nanocomposites using a stirring-assisted liquid route. Up to 0.5 wt-% of graphene nanoplatelets are used for the synthesis of nanocomposites. Testing and analysis of fabricated composites revealed improved metallurgy, mechanical properties and wear behaviour. Grain refinement action caused by graphene, high hardness, high strength and graphene's self-lubricating nature is reasoned for these improvements. An increase of 56.55% in ultimate tensile strength and 53.39% in microhardness over the base matrix is observed. The fractured surfaces are analysed through a scanning electron microscope to understand the fracture behaviour. The wear resistance of resultant composites is reported at a higher side, decreasing friction coefficient owing to graphene's self-lubricating nature. The impact of heat treatment on the mechanical behaviour of the synthesised composites is examined and discussed.
Uncertain Knowledge Graph Embedding: a Natural and Effective Approach
Authors: Yang Shihan , Tang Rui , Zhang Zhiwei , Li Guozhong
Published: April 2021

Uncertain Knowledge Graph (UKG) models uncertainty of the knowledge, which usually models the inherent uncertainty of relation facts in a knowledge base with a confidence value. Embedding such uncertain knowledge represents is still an unresolved challenge, although deterministic Knowledge Graph embedding has been extensively studied recently, which aims at representing entities and relations as vectors in a continuous vector space and preserving semantic information as much as possible. For capturing both structural and uncertainty information of relation facts in the continuous vector space, we propose a simple but effective two-steps approach to Uncertain Knowledge Graph Embedding (UKGE) based on the skip-gram/CBOW model and learning confidence score by Long Short-Term Memories (LSTM) neural network. We show that the embedding techniques achieve results comparing with state-of-the-art approaches on uncertain knowledge graph embedding. The approach achieves the best tradeoff between efficiency and accuracy of UKGE. Because of the simplicity, the method can also handle large size graphs in lower time consumption.
Word Embeddings for Constructive Comments Classification
Authors: Uribe Diego
Published: April 2021

Word embeddings are so significant today that it is common to see their application in multiple natural language tasks. Indeed, word embeddings as the first layer of a deep learning model are widely adopted and they can also be found in multiple natural language tasks such as classification of texts and named entity recognition. The focus of this paper is the identification of constructive online comments through the use of dense vector semantics such as word embeddings. We specifically explore two approaches: learning distributed word representations and the use of a pre-trained word embedding model. We evaluate these word embedding methods on a recently created constructive comments corpus comprised of 12,000 annotated news comments, intended to improve the quality of online discussions. The obtained results show how the performance of complicated architectures like recurrent and convolutional neural networks can be matched by a language model based on learning embeddings.
Impact of Randomization on Ensembles for Streams with Concept Drift
Authors: Goel Kanu , Batra Shalini
Published: April 2021

In the present era many real world applications are built from streaming data. The distribution of underlying data in such streams tend to change with course of time called as concept drift. A lot of algorithms are proposed in machine learning and data mining domain which are used to handle this drifting scenario. Ensembles form an integral component of such algorithms. In this paper, randomization is added using online bagging to the existing four drift handling approaches and its effect is analysed over multiple patterns of concept drift such as gradual, abrupt, recurring etc. Experimental work has been conducted over artificially generated data streams and real datasets to validate the impact of bagging in learning process.
The role of teacher educators in supporting STEM curriculum reform - lessons from New Zealand
Authors: Buntting Cathy
Published: April 2021

The beliefs and values teachers hold in relation to curriculum, pedagogy, assessment, and the nature of STEM have a significant influence on the types of teaching and learning their students will experience. Because of this, pre-service and in-service teacher education needs to influence teachers‘ beliefs and values as well as their conceptual and pedagogical knowledge if it is to make a difference in classroom practice. This paper considers the introduction of technology education in New Zealand as a way to explore how teacher educators can support STEM curriculum reform.
The development of early childhood students’ creative thinking problem solving abilities through STEM Education learning activities
Authors: Sangngam Suriyan
Published: April 2021

The purpose of this research was to study changes in early childhood students’ creative problem solving abilities comparing between before and after the intervention of STEM education learning activities. The sample group were male and female early childhood aged between 5-6 years studying in Soonthornwattana School, Chaiyaphum Province, 2nd semester, academic year of 2017. Methodology was the quasi-experiment design. The STEM education activities provided students to organize the nine square grid movement activities. Early childhood children’s creative thinking and problem solving ability was collected by the behavior observation form of creative problem solving skills (FCPS). The FCPS items consists of 12 items that represent the 3 items of access to problems, 3 items of thinking of a solution, 3 items of selection and preparation of problem solving, and 3 items of planning for solving problems. Then, each item of the FCPS was analysed for descriptive statistics. The results showed that early childhood who have been organized activities according to STEM Education’s theoretical concepts have developed more creative problem solving skills, with an average score of 14.63 and after the event will have a score of 24.27. When considering each aspect of the experiment, it was found that early childhood have creative problem-solving skills. Which has higher scores each week Shows that early childhood who have organized activities according to STEM Education’s theoretical concepts have higher creative problem-solving skills which is in accordance with the assumptions set forth.
Concept acquisition and scientific literacy of physics within inquiry-based learning for STEM Education
Authors: Yuliati Lia , Yogismawati Fitrika , Purwaningsih Endang , Affriyenni Yessi
Published: April 2021

This research to describe the acquisition of concepts and scientific literacy of students, especially in physics material, namely Newton’s Law, in inquiry-based learning for STEM education. This research is non-experimental research with descriptive and correlational approaches. The concept acquisition of students is explored based on Bloom’s Taxonomy indicators and scientific literacy is explored based on 3 dimensions, namely the dimensions of content, context, and competence. The research sample was 34 high school grade X students in East Java Indonesia who were determined by purposive sampling technique. Data obtained from opened ended and observation questions. Data were analyzed with descriptive statistics and product-moment correlation (r = 0.88). The results showed that the acquisition of Physics concepts in C3 level students (medium category) 14.70%; C4 level (high category) 47.06%; and the C5 - C6 level (very high category) 38.23%. Whereas students’ scientific literacy in the context category was 34%, content 52%, and competence 14%. Students who have good concept acquisition, they have good scientific literacy tendencies.
The technological knowledge and the content knowledge on acid-base concepts of senior high school STEM students
Authors: Nabua Edna B. , Falcasantos Jorgy O. , Jerez Maurine Joy Y.
Published: April 2021

The purpose of this study is to assess the levels of Technological Knowledge and Content Knowledge on Acid-Base Concepts and relationship between the Technological Knowledge and Content Knowledge on Acid-Base Concepts among the Senior High School STEM students in Iligan City. The study utilized two (2) Public High Schools in Iligan City schools division that offer STEM Strand. The respondents are the Senior High School STEM students that are taking up a Chemistry subject in the School Year 2018-2019. Questionnaires for Technological Knowledge and Content Knowledge on Acid-Base concepts were used. The collected data were analyzed using mean, frequency distribution, percentage, p-test, t-test, pearson correlation and levene’s test. The level of Technological Knowledge of Grade 11 STEM students in Iligan City National High School is very good. The level of Technological Knowledge of Grade 12 STEM students is also very good. The level of Technological Knowledge of Senior High School STEM students in Iligan City National High School is very good. The level of Content Knowledge on Acid- Base Concepts of Grade 11 students in Iligan City National High School is satisfactory. On the other hand, the result shows that the level of Content Knowledge on Acid- Base Concepts of Grade 12 STEM students one the same school is poor. Moreover, the level of Content Knowledge on Acid- Base Concepts of Senior High School STEM students in Iligan City National High School is poor. The level of Content Knowledge on Acid- Base Concepts of Senior High School STEM students in Iligan City East National High School is poor. The result shows that the difference and relationship of the technological knowledge and the content knowledge of Senior High School STEM students in Iligan City is not significant. Since the level of Technological Knowledge of the students were very good, teachers may make use the available technologies in teaching Acid- Base Concepts. Future researchers may utilize a larger population like different Schools Division in this region to validate this findings.