bluuebunny/crossref_metadata_2025 huggingface dataset:
Texture and exposure awareness based refill for HDRI reconstruction of saturated and occluded areas
Authors: Zhou Jianming , Deng Yipeng , Liu Qin , Ikenaga Takeshi
Published: May 2021

High‐dynamic‐range image (HDRI) displays scenes as vivid as the real scenes. HDRI can be reconstructed by fusing a set of bracketed‐exposure low‐dynamic‐range images (LDRI). For the reconstruction, many works succeed in removing the ghost artefacts caused by moving objects. The critical issue is reconstructing the areas which are saturated due to bad exposure and occluded due to motion with no ghost artefacts. To overcome this issue, this paper proposes texture and exposure awareness based refill. The proposed work first locates the saturated and occluded areas existing in input image set, then refills background textures or patches containing rough exposure and colour information into located areas. Proposed work can be integrated with multiple existing ghost removal works to improve the reconstruction result. Experimental results show that proposed work removes the ghost artefacts caused by saturated and occluded areas in subjective evaluation. For the objective evaluation, the proposed work improves the HDR‐VDP‐2 evaluation result for multiple conventional works by 1.33% on average.
Medical image encryption scheme based on self‐verification matrix
Authors: Man Zhenlong , Li Jinqing , Di Xiaoqiang
Published: May 2021

To mitigate the shortcomings of existing medical image encryption algorithms, including a lack of anti‐tampering methods and security, this report presents an anti‐tampering encryption algorithm for medical images that is based on a self‐verification matrix. First, chaotic coordinates generated by chaos are used to traverse all pixels in a plain image to generate a two‐dimensional matrix (a self‐verification matrix) with positioning information. The accurate location of illegally altered image pixels can be detected using the self‐verification matrix. To improve the security of the self‐authentication matrix, DNA coding is also applied to the self‐authentication matrix, and the plain image is also diffused statically to destroy the pixel distribution. Next, the scrambled image and self‐verification matrix are mixed and cross‐scrambled. Finally, the fused image is diffused dynamically to improve the security of the encrypted image. Experimental simulation and performance analysis show that the algorithm achieves good encryption effectiveness, provides strong anti‐tampering capabilities, and can accurately locate at least 4 pixels.
Layout optimisation algorithms and reliability assessment of wind farm for microgrid integration: A comprehensive review
Authors: Kumar Sachin , Saket R.K. , Dheer Dharmendra Kumar , Sanjeevikumar P. , Holm‐Nielsen Jens Bo , Blaabjerg Frede
Published: May 2021

The paper represents a comprehensive review of the wind farm layout and reliability assessment of the wind farm integrated electrical power system. The authors have done a review on the proliferation of renewable energy which raises the uncertainties in the electrical power system. The uncertainties including wind speed and wake effect are important to deal with when an isolated microgrid is considered. The scenario becomes vigilant when the wind farms are integrated with the main grid. Due to uncertainties, the study of reliability evaluation of a wind integrated power system would become significant to analyse the electrical power system behaviour effectively. So, the paper discusses the layout optimisation methods of wind turbines considering the uncertainty parameters, mainly the wake effect. In this regard, the different wake models and optimisation methods based on a single‐objective and multi‐objective functions are reviewed in detail with the proper comparisons. The paper serves as a better illustration of the competency of these optimisation methods on the optimal wind turbine location on a wind farm. Furthermore, the paper extends the view on the reliability and cost assessment, and reliability improvement techniques of the wind integrated power system. This article provides comprehensive information, yields an attractive and subsequent tool for research requirements for the researchers to design the wind farm layout, and assessed the reliability of a wind integrated power system.
Microgrid small‐signal stability analysis considering dynamic load model
Authors: Mahdavian Aram , Ghadimi Ali Asghar , Bayat Mohammad
Published: May 2021

Microgrids suitable operation depends on the system's proper design, based on accurate component models. A complete model considering entire system dynamics is a vital necessity for a successful design. Using dynamic load in microgrid small‐signal model results in a model that shows transient and steady‐state dynamics, since designing a low‐inertia system like microgrid need extra accuracy. In this paper, an inverter‐based microgrid's small‐signal model in islanded operation mode containing a dynamic load model has been achieved. The Exponential Recovery Load (ERL) model is presented here to study the dynamic behavior of load. Microgrid stability analysis has been carried out for both static and dynamic load models. To attain this goal, the entire component equations are obtained and linearized around an operating point, then the state‐space model is formed and eigenvalues are derived. System stability condition has been investigated by plotting eigenvalues and root locus method. In the final step, a simulation on Matlab/Simulink is performed to show the microgrids operation in the presence of a static and dynamic load.
Power line detection in millimetre‐wave radar images applying convolutional neural networks
Authors: Xiong Wei , Luo Jingsheng , Yu Chaopeng
Published: May 2021

High‐voltage power lines and their supporting towers create hazardous low‐altitude flight conditions for helicopters. Herein, a novel power line detection and classification is proposed for millimetre‐wave (MMW) radars applying Hough transform (HT) and convolutional neural network (CNN). HT is implemented to detect candidate lines in MMW radar images. Unfortunately, in the presence of background clutter and manmade structures, some false power lines are also brought in, thus it is vital to differentiate the actual power lines. Moreover, it is important to classify the power lines with and without Bragg pattern, and offer different threat levels. The authors firstly introduce the incidence angle and azimuth angle vectors of candidate lines as a supplement to power vectors, and propose a new CNN architecture for classification that uses powerful dense blocks and defined index pooling. With the trick of index pooling, the incidence angle and azimuth angle vectors can be merged with the corresponding power vectors together to mine the features, including those of Bragg pattern. Taking advantage of scale transformation, the proposed network adapts to different input scales. Extensive experiments demonstrate that the proposed method achieves state‐of‐the‐art results and is not sensitive to the input scales and noise levels.
Dechirp‐receiving radar target detection based on generalized Radon‐Fourier transform
Authors: You Pengjie , Ding Zegang , Liu Siyuan , Zhang Guangwei
Published: May 2021

The dechirp‐receiving radar measures range by the frequency difference between the target echo and the reference signal. It can operate at a low sampling frequency while transmitting a wideband signal, which simplifies the radar hardware. However, when detecting high‐speed and highly maneuvering targets, residual video phase (RVP), frequency mismatch, frequency modulation (FM) rate mismatch, and across range‐Doppler unit (ARDU) problems occur after dechirp receiving, which cause difficulties in integrating the target echo and result in severe performance loss. To solve these problems, the dechirp generalized Radon‐Fourier transform (DGRFT) and an algorithm for its fast implementation are proposed. The DGRFT compensates for the frequency and FM rate mismatch in the fast‐time domain and the RVP in the fast‐time frequency domain, and then implements joint envelope and phase compensations to overcome the ARDU phenomenon. After these compensations, the target echo can be effectively integrated. Experiments with simulated and measured data show that the performance of the DGRFT is better than that of the conventional moving target detector.
A novel fine Doppler frequency acquisition algorithm for BDS‐3 B1C signal based on an adaptive filter
Authors: Qiu Tongsheng , Wang Xianyi , du Qifei , Sun Yueqiang , Wang Zhuoyan
Published: May 2021

Fine Doppler frequency estimation has an important role in accelerating the convergence of the tracking loop in a global navigation satellite system (GNSS) receiver to achieve short time to first fix. BDS‐3 started broadcasting a civil B1C signal to provide open services for global users, which is beneficial for GNSS‐based applications. Therefore, a fine Doppler frequency acquisition algorithm based on an adaptive filter is proposed, whose purpose is to acquire the BDS‐3 B1C signal Doppler frequency accurately after the completion of coarse acquisition. The proposed algorithm is based on a first‐order complex‐coefficients adaptive filter. The adaptive filter depends on the proposed adaptation algorithm to track the input BDS‐3 B1C signal. An accurate Doppler frequency estimate is extracted. Simulation results show the proposed algorithm has high acquisition sensitivity, high acquisition accuracy, short acquisition time, and few hardware resources consumption, and also works well under many different coarse acquisition strategies. Overall, the proposed algorithm is better than the generic second‐order frequency locked loop. Consequently, the proposed algorithm has high practical value.
Prospects for kilonova signals in the gravitational-wave era
Authors: Mochkovitch R. , Daigne F. , Duque R. , Zitouni H.
Published: May 2021

The binary neutron star merger gravitational-wave signal GW170817 was followed by three electromagnetic counterparts, including a kilonova arising from the radioactivity of freshly synthesizedr-process elements in ejecta from the merger. Finding kilonovae after gravitational-wave triggers is crucial for (i) the search for further counterparts, such as the afterglow, (ii) probing the diversity of kilonovae and their dependence on the system’s inclination angle, and (iii) building a sample for multi-messenger cosmology. During the third observing run of the gravitational-wave interferometer network, no kilonova counterpart was found. We aim to predict the expected population of detectable kilonova signals for the upcoming O4 and O5 observing runs of the LIGO-Virgo-KAGRA instruments. Using a simplified criterion for gravitational-wave detection and a simple GW170817-calibrated model for the kilonova peak magnitude, we determine the rate of kilonovae in reach of follow-up campaigns and their distributions in magnitude for various bands. We briefly consider the case of GW190425, the only binary neutron star merger confirmed since GW170817, and obtain constraints on its inclination angle from the non-detection of its kilonova, assuming the source was below the follow-up thresholds. We also show that non-gravitational-wave-triggered kilonovae can be a numerous class of sources in future surveys and briefly discuss associations with short bright gamma-ray bursts. We finally discuss the detection of the jetted outflow afterglow in addition to the kilonova.
Isotopes of chlorine from HCl in the Martian atmosphere
Authors: Trokhimovskiy A. , Fedorova A. A. , Olsen K. S. , Alday J. , Korablev O. , Montmessin F. , Lefèvre F. , Patrakeev A. , Belyaev D. , Shakun A. V.
Published: May 2021

Hydrogen chloride gas was recently discovered in the atmosphere of Mars during southern summer seasons. Its connection with potential chlorine reservoirs and the related atmospheric chemistry is now of particular interest and actively studied. Measurements by the Atmospheric Chemistry Suite mid-infrared channel (ACS MIR) on the ExoMars Trace Gas Orbiter allow us to measure the ratio of hydrogen chloride two stable isotopologues, H35Cl and H37Cl. This work describes the observation, processing technique, and derived values for the chloride isotope ratio. Unlike other volatiles in the Martian atmosphere, because it is enriched with heavier isotopes, theδ37Cl is measured to be − 7 ± 20°, which is almost indistinguishable from the terrestrial ratio for chlorine. This value agrees with available measurements of the surface materials on Mars. We conclude that chlorine in observed HCl likely originates from dust and is not involved in any long-term, surface-atmosphere cycle.
The Rosebel gold mining district (Trans-Amazonian belt, Suriname), a new structural framework
Authors: Gapais Denis , Alimoenadi Gilian , Balraadjsing Nicole , Poupeau Benoît
Published: May 2021

The Rosebel gold district belongs to the Paleoproterozoic Trans-Amazonian belt associated with sub-meridian crustal shortening. Here, we present new structural observations (cleavage, stretching lineations, veins, fault slip data, aeromagnetic map). The regional cleavage is steeply dipping and bears a steeply plunging stretching lineation. Finite strains are of flattening type. Fault slip data reveal a complex deformation history. The overall strain pattern in the area reflects vertical motions, a feature consistent with pop-down tectonics involving vertical stretch and burial of supracrustal deposits during horizontal shortening of a hot and weak continental lithosphere.
Reliability analysis of solar energy and biogas boiler combination warming system
Authors: Zhao Jinhui , Han Xuwei , Bai Xuexiu
Published: May 2021

In order to solve the problem of low biogas production caused by low temperature in northern cold area, the solar energy and biogas boiler combination warming system is proposed to raise the temperature of biogas digester. In this paper, under the condition of the optimum area of solar collector, it's obtained that changeable rule of solar energy guarantee rate with month and rule of heating ratio of biogas boiler in the whole year. The solar energy guarantee rate of the system is more than 55.9%, and the combined heating capacity of solar energy and biogas boiler is enough to meet the requirements of annual operation conditions, which is reliable in the northern cold area.
Study on water purification with warm and cold season aquatic plants
Authors: Sun Jiajun , Zhang Yajie , Ma Guangyu , Xiao Junhong , Cai Yajing , Wang Zhi , Cao Hongbin
Published: May 2021

As a national key protection and restoration project, ecological restoration of Baiyangdian Wetland has an important significance for environmental management. As the research area in Zaozhadian wetland, the purification effect of warm season and cold season aquatic plants was studied under different overflying water qualities. It provides a theoretical and experimental basis for the ecological environment restoration and management of wetlands. The results showed that the warm season and cold season aquatic plants all played important roles on the nitrogen and phosphorus removal and maintained the stable water environmental from the nutrient release from soil. The warm season plant-mixedMyriophyllum spicatumandCeratophyllum demersumand the cold season plant-Potamogeton crispusL. can be reasonably configurated for the wetland restoration.
PV for PV to accelerate carbon neutrality
Authors: Yuan Quanhong
Published: May 2021

The cost of carbon neutrality is too expensive. How to find a cheaper and more feasible approach to realize it? This paper studies the innovative development mode of PV for PV-Max speed. Through the three-stage “PV for PV” development plan, After 2023, China's annual capacity can reach 400 GW, with a total investment of about $96 billion. After 2032, China's PV installation can reach 4000 GW, annual power generation is 5200TWh, and annual CO2 emission reduction is 4.4 Gt. After 2033, it will be an export period, with an annual export revenue of $54 billion. By 2046, it will be able to export a total of 5300 GW, with an annual power generation of 6890 TWh. It will reduce the CO2 emissions of 10.2 Gt for the world every year. If the PV plant is built in the three northern regions of China, combined with desertification control, the western desert will become a "green valley".
Research on removal of manganese in drinking water by potassium permanganate
Authors: Zhang Yukun , Dong Haishan , Yan Peng , Zheng Xue
Published: May 2021

Potassium Permanganate (KMnO4), which is a kind of strong oxidizer, is used in water production. As KMnO4 containing Manganese, the Manganese concentration may get higher concentration by overdosing additives, however, there isn’t any conclusion of the dosing interval in the present study. This paper used Manganese sand as catalyst and KMnO4 as oxidizer, trying to determine the optimal amount of the oxidizers, the dosing ratio and the dosing limit. The results showed that KMnO4 could remove manganese in drinking water effectively, when the addition ratio was 3.9, the removal efficiency of manganese reached 98%.
Research on control strategy for AC side asymmetric fault of MMC-HVDC transmission system
Authors: Zhang Mingguang , Sun Huzhong , Guo Richang , Shen Yao
Published: May 2021

When the Modular Multilevel Converter (MMC) fails on the AC side, the operating characteristics of MMC will be damaged. If the system wants to retain stable for a long time in the process of operation, it is obliged to design the control strategy in case of asymmetric fault. In this article, the control strategy based on feedback linearization principle is adopted to diminish the negative sequence current caused by breakdown, and a DC voltage controller is devised to suppress the fluctuation of the double frequency component under asymmetric fault conditions. The validity of the control strategy requires to be verified, the running results on PSCAD platform indicate this method is effective and feasible.
The study on the Mal-operation of the transformer current differential protection during external faults cause by CT saturation
Authors: Wu Jianhong , Qi Xuanwei , Song Wang , Cao Wenbin , He Jun , Mao Lan
Published: May 2021

This paper analyses the unusual mal-operation of the differential protection for transformer current differential protection during the external fault. The mal-operation reason is researched in detail, based on the mathematical analysis, the simulation, and the field recorded fault data analysis. It is disclosed that the CT saturation leads to the maloperation. Based on this, this paper analyses the improvement for the CT saturation identification method, and discusses the CT selection principles. This paper is aimed at attracting the attention on the problem of the CT saturation and proposing the reference of the analysis method the countermeasure for this problem.
Research on model component method based on OpenMI technology
Authors: Liu Haiyan , Liu Xiaomin , Xu Zhenhua
Published: May 2021

Open Model Interface (OpenMI) technology can construct standardized components with unified timing interface and standardized data interaction. This provides a standardized method for integrating multiple models with different interfaces and functions. This paper briefly introduces the operation principle of OpenMI technology and the process of model standardization, and describes the seven key steps of model transplantation by taking the one-dimensional hydraulic model of the Yellow River as an example.
Design and implementation of intelligent irrigation system
Authors: Hu Xiaofei , Sun Xia , Li Qinghong , He Qianqian , Li Yajun
Published: May 2021

In view of the problems existing in traditional irrigation, such as high time cost, poor reliability, waste of water resources. The intelligent irrigation system based on STM32 and BC95 is designed and implemented. The soil information is received through temperature sensor and humidity sensor, which is sent from the sampling node to the remote terminal serial port. The controller sends the signal to the output end for intelligent irrigation. The practice shows that the wireless communication mode of data transmission using STM32 and NB-IoT (narrow band-internet of things) technology can meet the requirements of reducing the time cost and enhancing the reliability of the system, and can meet the goal of data transmission of intelligent irrigation system and water-saving irrigation. it can be seen that the soil moisture data in the figure significantly changes.
Error analysis of hydraulic radius evaluation in hydraulic calculation
Authors: Yin Ye , Wang Dangwei , Wang Hantao , Deng Anjun , Feng Shenghang
Published: May 2021

Hydraulic radius is an important parameter in hydraulic calculation. It is often deemed that hydraulic radius can be replaced by the cross-sectional average water depth when the width to depth ratio (B/H) is greater than a certain value in traditional. Based on the various artificial cross-section and natural ones, value-taking errors of hydraulic radius are studied in this paper. The results show that it is feasible to adopt the average water depth as the hydraulic radius when B/H of rectangular section is larger than 40 or B/H of isosceles triangular section is larger than 12. But for natural river, B/H is different when water level changes and there is no single-valued corresponding relationship between relative error and B/H. Therefore, we advise that hydraulic radius could not be replaced by other variables in hydraulic calculation of natural rivers.
Study of novel high-density panels based on negative space welding technology with cells cut by different techniques
Authors: Zhuang Hao , Huang Guoping , Jiang Yashuai , Bai Xueliang , Sun Guan , Li Jingnan
Published: May 2021

Negative space welding technology (NSWT) is a newly adopted advanced technology for high-density solar panels. The benefit of this technology is its capability to improve the efficiency of panels. However, the introduction of a new technology or material may affect the original reliability. Some unexpected power loss may occur during its operation in different environments. Hence, in this work, damp heat (DH), thermal cycle (TC), UV irradiation and humidity freezing (HF) tests were utilized to evaluate the weatherability of NSWT-based panels fabricated with silicon cells cut by two different techniques. It is suggested by our results that these new panels with negative space between cells have good weatherability both in damp heat, dry heat and UV irradiation condition. The novel low-damage laser-induced cutting technique is beneficial for the improvement of module reliability.
Stiffness after unicompartmental knee arthroplasty: Risk factors and arthroscopic treatment
Authors: Fournier Gaspard , Gaillard Romain , Swan John , Batailler Cécile , Lustig Sébastien , Servien Elvire
Published: May 2021

Introduction: One of the principal complications after total knee arthroplasty (TKA) is stiffness. There are no publications concerning stiffness after unicompartmental knee arthroplasty (UKA). Study objectives were to describe the incidence of stiffness after UKA, to look for risk factors, and to describe safe and effective arthroscopic treatment. Methods: There were 240 UKA performed between March 2016 and January 2019 included. Robotic-assisted surgery was performed in 164 patients and mechanical instrumentation in 76 patients. Stiffness was defined as flexion < 90° or a flexion contracture > 10° during the first 45 post-operative days. Patients with stiffness were treated with arthroscopic arthrolysis. Several factors were studied to look for risk factors of stiffness: body mass index, gender, age, mechanical or robotic instrumentation, preoperative flexion, previous meniscectomy, and anticoagulant treatment. Arthrolysis effectiveness was evaluated by flexion improvement and UKA revision rate. Results: 22 patients (9%) developed stiffness. Mechanical instrumentation significantly increased the risk of stiffness with OR = 0.26 and p = 0.005. Robotic-assisted surgery decreased the risk of stiffness by five-fold. Before arthrolysis, mean knee flexion was 79°, versus 121° (53% improvement) after arthroscopic arthrolysis. Only 2 patients (9%) underwent UKA revision after arthrolysis. Discussion: Stiffness after UKA is an important complication with an incidence of 9% in this study. Arthroscopic arthrolysis is a safe and effective treatment with a range of motion improvement of > 50%. Robotic-assisted surgery significantly decreases the risk of postoperative stiffness.

Level of evidence: Level III, therapeutic study, retrospective cohort study
Treatment of Patients with Early Breast Cancer: Evidence, Controversies, Consensus
Authors: Untch Michael , Fasching Peter A. , Brucker Sara Y. , Budach Wilfried , Denkert Carsten , Haidinger Renate , Huober Jens , Jackisch Christian , Janni Wolfgang , Kolberg-Liedtke Cornelia , Krug David , Kühn Thorsten , Loibl Sibylle , Lüftner Diana , Müller Volkmar , Schneeweiss Andreas , Thill Marc , Harbeck Nadia , Thomssen Christoph
Published: May 2021

This yearʼs 17th St. Gallen (SG) Consensus Conference on the Treatment of Patients with Early Breast Cancer (SG-BCC) with the title “Customizing local and systemic therapies for women with early breast cancer” focused on the challenge of targeting the treatment of early breast cancer more specifically to the individual disease situation of each patient. As in previous years, a German working group of leading breast cancer experts discussed the results of the international SG-BCC 2021 in the context of the German guideline. It is helpful to compare the SG recommendations with the recently updated treatment recommendations of the Breast Commission of the German Working Group on Gynaecological Oncology (Arbeitsgemeinschaft Gynäkologische Onkologie e. V., AGO) and the S3 guideline because the SG-BCC panel comprised experts from different countries, which is why country-specific aspects can be incorporated into the SG recommendations. The German treatment recommendations of
the AGO and the S3 guideline are based on current evidence. Nevertheless, any therapeutic decision must always undergo a risk-benefit analysis for the specific situation and to be discussed with the patient.
Stille Hypoxie nach COVID-19 – gefährliche Unbekannte für die Rehabilitation
Authors: Elmer Nancy , Reißhauer Anett , Liebl Max Emanuel
Published: May 2021

Die „stille Hypoxie“ bezeichnet Abfälle der Sauerstoffsättigung ohne Symptomdruck und ohne physiologische Reaktion wie einer Zunahme der Atemarbeit oder Herzfrequenz. Die stille Hypoxie existiert auch in der Rekonvaleszenzphase nach einer schweren SARS-CoV-2-Infektion. Solange eine stille Hypoxie nicht ausgeschlossen wurde, sollten bei allen physio- und sporttherapeutischen Maßnahmen, stationär und ambulant, die üblichen Parameter wie Herzfrequenz, Dyspnoe (Borg-CR-Skala) und Atemfrequenz nicht zur Steuerung der Therapie-Intensität verwendet werden.
Benefits of Endoscopic Sheath in Intraventricular Neuroendoscopy: Technical Note
Authors: Marx Sascha , Schroeder Henry W.S.
Published: May 2021

Background The usefulness of the endoscopic sheath is underreported in the literature.

Objective and Methods To explain the use of an endoscopic sheath and to highlight its benefits.

Results In addition to protecting the surrounding brain parenchyma when inserting the endoscope, the endoscopic sheath is a very useful tool to retract neurovascular structures, achieve hemostasis, and create adequate working space within narrow ventricles. The sheath can be moved within the ventricular system, and the endoscope can be moved independently within the sheath. These movements represent all the advantages of the endoscopic sheath.

Conclusions We used an endoscopic sheath in ∼ 300 intraventricular neuroendoscopic procedures and consider the sheath an essential part of a ventriculoscopic system. Proper use of the sheath can help avoid or manage endoscopic complications.
The Use of Electrophilic Cyclization for the Preparation of Condensed Heterocycles
Authors: Slivka Mikhailo , Onysko Mikhailo
Published: May 2021

Condensed heterocycles are well-known for their excellent biological effects and they are undeniably important compounds in organic chemistry. Electrophilic cyclization reactions are widely used for the synthesis of mono-heterocyclic compounds. This review highlights the utility of electrophilic cyclization reactions as an effective generic tool for the synthesis of various condensed heterocycles containing functional groups that are able to undergo further chemical transformations, such as nucleophilic substitution, elimination, re-cyclization, cleavage, etc. This review describes the reactions of unsaturated derivatives of different heterocycles with various electrophilic agents (halogens, arylsulfanyl chlorides, mineral acids) resulting in annulation of an additional partially saturated heterocycle. The electrophilic reaction conditions, plausible mechanisms and the use of such transformations in organic synthesis are also discussed. The review mainly focuses on research published since 2002 in order to establish the current state of the art in this area.

1 Introduction

2 Electrophilic Cyclization Pathways Involving a Nitrogen Nucleo­philic Center

3 Electrophilic Cyclization Pathways Involving a Chalcogen Nucleophilic Center

3.1 Sulfur Centers

3.2 Oxygen Centers

3.3 Selenium Centers

4 Strategies and Mechanisms

5 Conclusion
Deuterium-Labeling Studies on the C–H/Olefin Coupling of Aromatic Ketones Catalyzed by Fe(PMe3)4
Authors: Kakiuchi Fumitoshi , Kimura Naoki , Katta Shiori , Kitazawa Yoichi , Kochi Takuya
Published: May 2021

Deuterium-labeling experiments were performed for the Fe(PMe3)4-catalyzed C–H/olefin coupling using a deuterium-labeled aromatic ketone with various alkenes. While the reactions with a variety of alkenes provided the linear alkylation products formed via 1,2-insertion of alkene into an Fe–H bond, the reversible 2,1-insertion proceeded during the reaction highly depends on the choice of the alkene. No H/D scrambling resulting from 2,1-insertion/β-elimination was detected for the reactions with a vinylsilane and N-vinylcarbazole, but the reactions­ with styrenes are considered to involve rapid 2,1-insertion/ β-elimination processes to cause significant levels of H/D scrambling.
Vascular Spinal Cord Disorders
Authors: English Stephen W. , Zalewski Nicholas L.
Published: May 2021

Vascular disorders of the spinal cord are uncommon yet under-recognized causes of myelopathy. Etiologies can be predominantly categorized into clinical and radiographic presentations of arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage. While vascular myelopathies often produce significant morbidity, recent advances in the understanding and recognition of these disorders should continue to expedite diagnosis and proper management, and ideally improve patient outcomes. This article comprehensively reviews relevant spinal cord vascular anatomy, clinical features, radiographic findings, treatment, and prognosis of vascular disorders of the spinal cord.
Imaging Considerations in Spinal Cord Evaluation
Authors: Shea Alice C. , Kuo Anderson H. , Hsu Liangge
Published: May 2021

Multiple diverse pathologies result in the clinical presentation of myelopathy. The preferred way to image the spinal cord depends on clinical history, anatomic site of interest, and patient issues limiting certain imaging modalities. This radiology-focused article discusses pertinent physiological considerations, reviews basic and newer imaging techniques, and examines several distinct disease entities in order to highlight the key role of imaging in the work-up of myelopathy.
Long-term Radiologic and Clinical Outcomes after Three-level Contiguous Anterior Cervical Diskectomy and Fusion without Plating: A Multicentric Retrospective Study
Authors: Ricciardi Luca , Scerrati Alba , Bonis Pasquale De , Miscusi Massimo , Trungu Sokol , Visocchi Massimiliano , Papacci Fabio , Raco Antonino , Proietti Luca , Pompucci Angelo , Olivi Alessandro , Montano Nicola
Published: May 2021

Background Anterior cervical diskectomy and fusion (ACDF) has been providing good surgical, clinical, and radiologic outcomes in patients suffering from cervical degenerative disk disease (DDD). However, the role of anterior plating is still debated, especially in three-level procedures. This study aimed to investigate long-term clinical and radiologic outcomes and complications after three-level contiguous ACDF without plating for cervical DDD.

Methods Two institutional databases were retrieved (January 2009–December 2014) for patients treated with three-level contiguous ACDF without plating. Minimum follow-up (FU) was 5 years. Demographical data, smoking status, implant types, Neck Disability Index (NDI), visual analog scale (VAS) for neck pain, complications, fusion rate, adjacent segment degeneration (ASD), cervical lordosis (CL), and residual segmental mobility were evaluated.

Results We enrolled 21 patients. Tantalum and carbon fiber cages were implanted, respectively, in 13 and 8 patients. The mean FU length was 5.76 ± 0.87 years. Mean NDI score was 78.29 ± 9.98% preoperatively and 8.29 ± 1.67% at last FU (p < 0.01), whereas mean VAS score decreased from 7.43 ± 1.14 preoperatively to 0.95 ± 0.95 at last FU (p < 0.01). Complications were one postoperative hematoma, one superficial wound infection, and five cases of postoperative dysphagia (recovered within 3 days). The fusion rate was 90% and ASD was reported in three (14%) cases. The mean CL was 6.33 ± 2.70 degrees preoperatively, 8.19 ± 1.97 degrees 3 months after surgery (p = 0.02), and 7.62 ± 1.96 degrees at latest FU. There was no residual mobility on every operated segment at last FU. The smoking status was an independent risk factor for nonfusion in this case series (p = 0.02).

Conclusions Three-level contiguous ACDF without plating seems to be an effective treatment for cervical DDD. Properly designed comparative clinical trials are needed to further investigate this topic.
Hyperchloremia on Admission to Pediatric Intensive Care in Mechanically Ventilated Children is Associated with Impaired Renal Function
Authors: Mitting Rebecca B. , Ramnarayan Padmanabhan , Inwald David P.
Published: May 2021

Objective There is recent interest in the association between hyperchloremic metabolic acidosis and adverse outcomes. In vitro, hyperchloremia causes renal vasoconstriction and fall in glomerular filtration rate (GFR). The objective of this retrospective, observational study is to examine associations between chloride level at admission to pediatric intensive care (PICU) and worst GFR and requirement for renal replacement therapy.

Materials and Methods All admissions to PICU between 2009 and 2019 who received invasive mechanical ventilation and had blood gas analysis performed were included. Data analyzed included patient characteristics (age, gender, diagnosis, pediatric index of mortality [PIM]-2 score); results of initial blood gas; and maximum serum creatinine (then used to calculate minimum GFR). Primary outcome measure was worst GFR during PICU stay. Secondary outcome measures were requirement for renal replacement therapy and PICU mortality. Multivariable regression analysis was used to assess if admission chloride level was independently predictive of minimum GFR during PICU stay and to examine associations between hyperchloremia (>110 mEq/L) at admission and requirement for renal replacement therapy after adjustment for confounders.

Results Data were available for 2,217 patients. Median age was 16.4 months and 39% of patients were hyperchloremic at admission to PICU. Admission chloride level was independently predictive of worst GFR during PICU stay after adjustment for known confounders. Patients with hyperchloremia were not more likely to require renal replacement therapy or die than patients with normochloremia.

Conclusion Prospective studies are necessary to determine if high chloride, specifically chloride containing resuscitation fluids, have a causal relationship with poor outcomes.
Surgical Antimicrobial Prophylaxis–Where Do We Stand?
Authors: Jha Anuja , Agrawal Manju , Hishikar Rajesh , Jha Himanshu Shekhar
Published: May 2021

Introduction

Surgical site infection (SSI) is the commonest preventable health care–associated infection among postoperative cases. Several guidelines are available for surgical antimicrobial prophylaxis (SAP) and other measures which prevent SSI. National Center for Disease Control (NCDC), India, has also provided a guideline for prevention of SSI in 2016. In this study we have compared the NCDC, India, guideline with WHO (World health organization) and American Society of Health System Pharmacists (ASHP) guidelines. The timing of antimicrobial agent administration is the only parameter which is included in all the three guidelines. As per NCDC and ASHP it should be within 60 minutes of incision while as per WHO it is within 120 minutes of incision.

Materials and Methods

This was a prospective observational study—104 patients undergoing surgery in general surgical ward between January 2016 and June 2017 were included in this study. The NCDC guideline was compared with WHO and ASHP guidelines. Real data comparison was done for those parameters which were included in all the three guidelines.

Statistical Analysis

Data were analyzed using descriptive methods and chi-square test.

Results

None of the patients in our study received SAP within 60 minutes of incision. In 70% cases it was administered within 2 hours of incision and in the remaining 30% it was administered after more than 2 hours. There was no significant difference in the incidence of SSI among these two groups.

Conclusion

NCDC SAP guideline helps in rational use of antimicrobials. Increasing the duration for SAP may be added in the NCDC guidelines. Inclusion of certain additional parameters like weight-based doses and consideration for other comorbidities will help in patient- and procedure-specific SAP. Antimicrobial stewardship should be encouraged in all the hospitals and should follow local antimicrobial resistance pattern. This will assist in therapy decision, policy making, and evidence-based treatment.
Differences in regional music show up in statistical analyses via symbolic dynamics
Authors: Bandari Anashe
Published: May 2021

There are obvious differences in traditional music from region to region. Researchers aim to quantify these differences using statistical and symbolic methods.
A setup to measure the temperature-dependent heating power of magnetically heated nanoparticles up to high temperature
Authors: Mille N. , Faure S. , Estrader M. , Yi D. , Marbaix J. , De Masi D. , Soulantica K. , Millán A. , Chaudret B. , Carrey J.
Published: May 2021

Magnetic heating, namely, the use of heat released by magnetic nanoparticles (MNPs) excited with a high-frequency magnetic field, has so far been mainly used for biological applications. More recently, it has been shown that this heat can be used to catalyze chemical reactions, some of them occurring at temperatures up to 700 °C. The full exploitation of MNP heating properties requires the knowledge of the temperature dependence of their heating power up to high temperatures. Here, a setup to perform such measurements is described based on the use of a pyrometer for high-temperature measurements and on a protocol based on the acquisition of cooling curves, which allows us to take into account calorimeter losses. We demonstrate that the setup permits to perform measurements under a controlled atmosphere on solid state samples up to 550 °C. It should in principle be able to perform measurements up to 900 °C. The method, uncertainties, and possible artifacts are described and analyzed in detail. The influence on losses of putting under vacuum different parts of the calorimeter is measured. To illustrate the setup possibilities, the temperature dependence of heating power is measured on four samples displaying very different behaviors. Their heating power increases or decreases with temperature, displaying temperature sensibilities ranging from −2.5 to +4.4% K−1. This setup is useful to characterize the MNPs for magnetically heated catalysis applications and to produce data that will be used to test models permitting to predict the temperature dependence of MNP heating power.
Averaging principle for a type of Caputo fractional stochastic differential equations
Authors: Guo Zhongkai , Hu Junhao , Yuan Chenggui
Published: May 2021

The averaging principle for Caputo fractional stochastic differential equations has recently attracted much attention. In this paper, we investigate the averaging principle for a type of Caputo fractional stochastic differential equation. Comparing with the existing literature, we shall use different estimate methods to investigate the averaging principle, which will enrich the development of theory for Caputo fractional stochastic differential equations.
The relation between shearing motions and the turbulent/non-turbulent interface in a turbulent planar jet
Authors: Hayashi M. , Watanabe T. , Nagata K.
Published: May 2021

The relation between shearing motions and the turbulent/non-turbulent interfacial (TNTI) layer is studied with direct numerical simulation of a temporally evolving planar jet. Small-scale shear layers are detected with the triple decomposition of the velocity gradient tensor, which is decomposed into shear, rotation, and elongation tensors. The shear layers are found in the turbulent sublayer more frequently than in the turbulent core region although they hardly appear in the viscous superlayer. The shear layers undergo a biaxial strain with stretching in the shear vorticity direction and compression in the interface normal direction. This compressive strain is related to the non-turbulent fluid, which is relatively advected toward the shear layer. The shear layer thickness in the TNTI layer is well predicted by Burgers vortex layer. The velocity jump of the shear layer is about seven times the Kolmogorov velocity both in the turbulent core region and the TNTI layer. However, the layer thickness normalized by the Kolmogorov scale is about 6 in the turbulent core region and decreases in the TNTI layer, where consequently, the shear Reynolds number becomes small. The shear layers have significant contributions to the enstrophy production in the turbulent sublayer and the viscous enstrophy-diffusion toward the viscous superlayer. The shear layer and the outer edge of the TNTI layer have a curvature radius of about 50 times the Kolmogorov scale. The alignment between the shear layer orientation and the interface normal direction confirms that the shear layers near the interface are mostly parallel to the TNTI layer.
Detrimental effects and mitigation of the joint feature in double shell implosion simulations
Authors: Stark D. J. , Sauppe J. P. , Haines B. M. , Palaniyappan S. , Sacks R. F. , Sagert I. , Keiter P. A. , Montgomery D. S. , Morrow T. , Patterson B. M. , Quintana T. E. , Kuettner L. , Goodwin L. , Batha S. H. , Loomis E. N.
Published: May 2021

Double shell capsules provide an attractive option in inertial confinement fusion experiments due to their potential for achieving a low-convergence, robust burn. However, these designs suffer from symmetry degradation and accompanying reduced fuel confinement due to the currently necessary joint between the two hemispheres of the outer shell. The gap widens as a result of the excess ablation pressure produced by x rays that penetrate the joint during the drive phase, and this perturbation grows and imprints onto the inner shell during the collision. xRAGE Eulerian radiation-hydrodynamic simulations predict significant reductions in deuterium–tritium fusion yields compared to joint-less simulations when the depth of the outer joint is increased, whereas the performance is less sensitive to the depth of the inner gap. Here we examine the technique of plating the insides of the outer gap with a high-Z material to mitigate the impact of this feature. Gold-plating in quantities comparable to or exceeding the “missing” outer shell mass shows promise toward restoring both implosion symmetry and yield closer to the joint-less levels, and synthetic diagnostics suggest that high-energy x-ray radiographs can capture this shape retention of the inner and outer shells in experiments.
Direct numerical simulation of vortex structures during the late stage of the transition process in a compressible mixing layer
Authors: Chong Daotong , Bai Yuping , Zhao Quanbin , Chen Weixiong , Yan Junjie , Hong Yibo
Published: May 2021

The paper describes the direct numerical simulation (DNS) of a spatially developing compressible mixing layer with a convective Mach number of 0.8. The work mainly studies on the evolution process and formation mechanism of vortex structures during the late stage of transition process. In flow visualizations, multiple ring-like vortices and multiple necklace-like vortices appear during the late stage of the transition process. These multiple necklace-like vortices have never previously been reported in a compressible mixing layer. The formation mechanism is presented that the Kelvin–Helmholtz instability (K–H instability) of shear layers is the root cause of multiple ring-like vortices and multiple necklace-like vortices. DNS results indicate that new shear layer regions form around the corresponding Λ-vortices as the result of the first ejection and sweep events from each Λ-vortex. As a consequence, ring structures form one by one because of the K–H instability of shear layers, which represents the formation of multiple ring-like vortices. As the flow proceeds, several new local shear layer regions are generated around the ring structures, induced by the second ejection and sweep events from the rings of the multiple ring-like vortices. Bridge structures are then induced one by one by the K–H instability of shear layers, representing the formation of multiple necklace-like vortices. In addition, DNS results show that, from the first multiple necklace-like vortex onward, dominant vortex structures develop separately in the upper and lower layers until flow runs into the fully developed turbulent state. In the process, vortex structures in the upper layer clearly lag behind those in the lower layer.
FEbeam: Cavity and electron emission data conversion, processing, and analysis. A freeware toolkit for rf injectors
Authors: Schneider Mitchell , Jevarjian Emily , Shao Jiahang , Baryshev Sergey V.
Published: May 2021

FEbeam is an all-in-one field emission data processing interface with the capability to analyze the field emission cathode performance in an rf injector by extracting the field enhancement factor, local field, and effective emission area from the Fowler–Nordheim equations. It also has the capability of processing beam imaging micrographs using its sister software, FEpic. The current version of FEbeam was designed for the Argonne Cathode Test-stand of the Argonne Wakefield Accelerator facility switch yard. With slight modifications, FEbeam could work for many rf field emission injectors. This software is open-source and can be found at GitHub.