bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal distributed generation and battery energy storage units integration in distribution systems considering power generation uncertainty
Authors: Khasanov Mansur , Kamel Salah , Rahmann Claudia , Hasanien Hany M. , Al‐Durra Ahmed
Published: June 2021

This paper proposes an application of the recent metaheuristic rider optimization algorithm (ROA) for determining the optimal size and location of renewable energy sources (RES) including wind turbine (WT), photovoltaic (PV), and biomass‐based Distributed Generation (DG) units in distribution systems (DS). The main objective function is to minimize the total power and energy losses. Power loss‐sensitivity factor (PLSF) is used with the ROA to determine the suitable candidate buses and accelerate the solution process. The Weibull and Beta probability distribution functions (PDF) are employed to characterize the variability of wind speed and solar radiation, respectively. The high penetration of intermittent renewable resource together with demand variations has introduced many challenges to distribution systems such as power fluctuations, voltage rise, high losses, and low voltage stability, therefore battery energy storage (BES) and dispatchable Biomass are considered to smooth out the fluctuations and improve supply continuity. The standard 33 and 69‐bus test systems are used to verify the effectiveness of the proposed technique compared with other well‐known optimization techniques. The results show that the developed approach accelerates to the near‐optimal solution seamlessly, and in steady convergence characteristics compared with other techniques.
Research on influence factors of corona onset characteristics of AC grading rings based on three‐dimensional calculation physical model
Authors: Huang Shilong , Yan Xiaoliang , Liu Yunpeng , Zhang Guangzhou , Tang Jian , Liu Chen , Li Yongshuang , He Wangling
Published: June 2021

In order to obtain the influence laws and mechanisms of size parameters (ring diameter and pipe diameter) of the grading ring and environmental parameters (atmospheric pressure, temperature, and humidity) on corona onset characteristics of a grading ring, a three‐dimensional (3‐D) calculation physical model of corona onset considering the influence of size parameters of the grading ring and environmental parameters is established by proposing an area factor of a photon absorption function suitable for the grading ring. Combined with the thickness of ionised layer and the effective ionisation coefficient, the influence mechanisms of size parameters of the grading ring and environmental parameters on corona onset characteristics are given. The calculation results show that with the increase of the pipe diameter and ring diameter, the corona onset voltage increases gradually and the corona onset field intensity decreases gradually. The increase of the effective ionisation coefficient leads to the expansion of ionisation region, which leads to the decrease of corona onset voltage with the decrease of atmospheric pressure and the increase of temperature. The enhancement of capacity for collisional ionisation in the region with the high field intensity leads to the decrease of corona onset voltage with the increase of humidity.
Integral equation modelling of unmanned aerial vehicle radar scattering characteristics in VHF to S frequency bands
Authors: Zalevsky Gennady S. , Sukharevsky Oleg I. , Vasylets Vitaly A.
Published: June 2021

Methods for modelling the radar scattering characteristics of resonance‐size airborne objects containing metallic and dielectric design elements are discussed. The developed algorithms are based on solving Fredholm second‐kind boundary integral equations (IEs) that place them within the context of the method of analytical regularisation. The magnetic field IE is used for metal elements, and the Müller IE set is used for dielectric elements. The proposed algorithms provide important novelties in calculating the radar scattering characteristics of objects with various curvature radii, including electrically thin scatterers. The description is accompanied by an analysis of developed algorithm convergence. For the validation, a comparison of results for model object obtained by different methods is presented. The results of modelling the radar scattering characteristics of an unmanned aerial vehicle and its separate metallic and dielectric elements within the VHF and S frequency bands are demonstrated and discussed.
How rare are counter Evershed flows?
Authors: Castellanos Durán J. S. , Lagg A. , Solanki S. K.
Published: June 2021

One of the main characteristics of sunspot penumbrae is the radially outward-directed Evershed flow. Only recently have penumbral regions been reported with similar characteristics to normal penumbral filaments but with an opposite direction of the flow. Such flows directed toward the umbra are known as counter Evershed flows (CEFs). We aim to determine the occurrence frequency of CEFs in active regions (ARs) and to characterize their lifetime and the prevailing conditions in the ARs. We analyzed the continuum images, Dopplergrams, and magnetograms recorded by SDO/HMI of 97 ARs that appeared from 2011 to 2017. We followed the ARs for 9.6 ± 1.4 days on average. We found 384 CEFs in total, with a median value of six CEFs per AR. Counter Evershed flows are a rather common feature, occurring in 83.5% of all ARs regardless of the magnetic complexity of the AR. However, CEFs were only observed, on average, during 5.9% of the mean total duration of all the observations analyzed here. The lifetime of CEFs follows a log-normal distribution with a median value of 10.6−6.0+12.4 h. In addition, we report two populations of CEFs, those that are associated with light bridges and those that are not. We explain that the rarity of reports of CEFs in the literature is a result of highly incomplete coverage of ARs with spectropolarimetric data. By using the continuous observations now routinely available from space, we are able to overcome this limitation.
Quantitative study on benefits of distribution network investment
Authors: Yongxiu He , Ye Lu
Published: June 2021

The development of distribution network in China lags behind the transmission network seriously, which is difficult to meet the development needs of high proportion of renewable energy power system in the future. Facing the huge investment demand of distribution network, it is urgent to improve the existing extensive experience based investment decision-making method and avoid the subjectivity of qualitative index evaluation method. In this paper, the life cycle theory and input-output method are used to study the quantification of distribution network investment benefit. The quantitative models of economic benefit and social benefit of distribution network investment are established to provide support for the comparison and decision-making of distribution network projects. Finally, an empirical analysis of the investment benefit model of a high-voltage distribution network project is carried out to verify the feasibility of the research results.
Research on elecctro-sorption method for air conditioning system with binary solution
Authors: Li Chenchen , Li Xiuwei , Li Yonghang
Published: June 2021

Absorption air-conditioning system is a green air-conditioning system. With binary solution as the working fluid, the system performance is better with lower cost. To further improve the efficiency, an electrosorption method is proposed to regenerate the absorbent solution. Its principle is similar to capacitive deionization. The system with LiBr-CaCl2 has been confirmed in the improvement of performance, while the cost-effectiveness wasn’t ideal to satisfy the need of some cases. To solve this problem, the system with MgCl2-CaCl2 is proposed to analyze the enhancement in the cost-effectiveness. The theoretical and experimental results verify the advantage in the cost-effectiveness compared to the system with LiBr-CaCl2. Although the performance of the system with MgCl2-CaCl2 is lower than the other mixed solution, the actual COP could reach 1.9, which is still better than the system with single absorbents. Meanwhile, the energy recovery characteristic could further enhance the advantage in the improvement of performance for the system with LiBr-CaCl2 and make up the weakness of the system with MgCl2-CaCl2 solution. The exploration of higher energy recovery efficiency will further improve the competitiveness of the system.
Multivariate analysis and optimal configuration of wind-photovoltaic complementary power generation system
Authors: Guangwei Wang , Ziqin Su , Shixin Li , Tai Chen
Published: June 2021

Advantages of wind-solar complementary power generation system to utilize solar and wind energy in the aspect of resource and technical economy have been reviewed tersely. Convenience of entering and exiting generating equipment and load from DC as well as AC bus are interpreted briefly. The factors that affect the electrical power output of the system were analyzed and studied. Based on the law of energy conservation, the energetic matching algorithm was proposed which forms the foundation of optimal configuration of system. Finally, the intelligent control and on-line monitoring of wind-solar complementary power generation system were discussed.
CCS-MPC for PMSM with Wide Speed Range based on Variable DC-Bus Voltage Control applied to the Flywheel Energy Storage System
Authors: Tian Aobo , Gao Congzhe , Lv Jingliang , Jiang XinJian
Published: June 2021

In this paper, in order to verify the effect of variable DC-bus voltage control, CCS-MPC (Continuous-Control-Set MPC) control is used to research the control of PMSM (Permanent-Magnet Synchronous Machine) in a wide speed range. In order to maximize the speed of PMSM, the MTPA control, the field weakening control and the variable DC-bus voltage control are applied in the different speed range of PMSM. CCS-MPC can eliminate the control delay by controlling the predicted step size. When CCSMPC is applied to the PMSM control with a wide speed range, the advantages of strong adaptability of CCS-MPC can be exerted.
Study on Total Amount Accounting of Pollutants Entering Qinghe River Basin
Authors: Zhuo Han , Ji Zhang , Jialiang Su , Zhiyuan Zheng , Shuaiyu Lu , Weiwei Zhou , Jinxiang Fu
Published: June 2021

The calculation of the total amount of pollutants entering the river is the key to the total amount control system. Since non-point source pollution has not been monitored normally and effectively, based on the principle of the balance of input and output of pollutants, the 2009-2013 Qinghe water quality monitoring data, pollution source survey data and monitoring data were used to establish a binary statistics of the total amount of pollutants model. MATLAB software is used to solve the model. The results show that the model has strong data assimilation ability, can accurately calculate the monthly COD inflow into the river, can divide the point source and non-point source pollution load, and can meet the needs of actual research.
Research on the coordination degree of ecological protection and high-quality development of urban agglomerations in the Yellow River Basin
Authors: Zhao Jinhui , Bai Yunlong , Zhang Chao , He Jiawei , Li Siyuan
Published: June 2021

The Yellow River Basin is ecologically fragile, the relationship between water and sand is unbalanced and water resources are scarce. This paper takes the urban agglomerations in the Yellow River Basin as the research object, based on the guidelines for the coordinated promotion of ecological protection and high-quality development in the basin, and uses the entropy weight method and the coefficient of variation method as the means to establish a quantitative evaluation system for coordinated development. The degree of synergy is between ecological protection and high-quality development of the urban agglomerations from the time dimension and the space dimension, and we give the optimization directions. The results show that the degree of synergy among urban agglomerations in the river basin is steadily increasing, but there are significant spatial differences in the degree of coordination of ecological protection and high-quality development of the urban agglomerations and the development index of its subsystems. The degree of synergy generally presents a cascade distribution pattern that gradually decreases from east to west and from downstream to upstream. The ecological destruction, economic fluctuations and water waste of the river basin urban agglomeration are the main factors hindering the improvement of synergy.
Study on Post-Transformation Assessment and Green Renewal of Binjiang in Shanghai
Authors: Hongyan Pan , Gaijing Zhang
Published: June 2021

This paper takes the Binjiang industrial zone of Shanghai as the research object, based on the transformation and development of Binjiang in Shanghai and the renewal of existing urban industrial buildings in recent years, takes green building as the focus to vigorously promote the sustainable and energysaving development of the region. With the goal of improving the vitality and quality of the city, it explores a progressive and sustainable organic regeneration model for the riverfront industrial zone. Through the research and analysis of "green growth and ecological renewal", it establishes a comprehensive posttransformation impact assessment system for the Binjiang industrial belt with three dimensions of transformation connotation: assessment object, functional positioning and transformation direction.Binjiang in Yangpu District and Binjiang in Xuhui District are used as cases for assessment and analysis, and four aspects of industrial function upgrading, building green growth, environmental quality improvement, and industrial culture inheritance are proposed to develop green renewal development strategies for the transformation and development of Binjiang, which provide technical support for the transformation of the future urban Binjiang industrial belt.
Study on Dynamic Change of Land Use in Qingzhen City Based on GIS Technology and CA-Markov Model
Authors: Bai Yi , Li Song , Zuo Qianqin , Zhang Wei
Published: June 2021

With the rapid development of social economy, the sustainable use of land is becoming more and more important. Based on GIS and remote sensing technology, the work processed the land use status data of Qingzhen in 2016 and 2020, obtained the dynamic change data during the period, analyzed its land use structure, quantity and degree. Finally, we used the CA-Markov model to obtain the flow direction and probability of land use type. Results showed that the rate of non-agricultural land increase, and the rate of other land reduce. Suggestions :(1) centralization of land resources and integration of urban and rural development.(2) Continue to develop characteristic industries and create new business cards for the city.(3) Pay attention to the quality of cultivated land and rationally develop unused land.
Analysis of the status quo of solar heating under the background of carbon neutrality
Authors: Kong Dexia , Liang Jun
Published: June 2021

Since 2020, under the market trend of the "carbon peak" and "post-coal reform" era, clean energy heating has ushered in development opportunities. This article mainly introduces the current status of solar combined heat pump, biomass energy, electricity, photovoltaic and other heating methods, compares the differences of various types of energy heating, analyzes the advantages and limitations of solar heating, and puts forward reasonable suggestions.
Early diagnosis and precise treatment of hepatocellular carcinoma
Authors: Zhao Wenxing
Published: June 2021

Liver cancer is called the "king of cancer" because of its extremely high mortality rate and lack of effective treatment methods. Effective early diagnosis of liver cancer and advance discovery period of liver cancer can effectively improve the survival rate and life cycle. Early diagnosis can be done by traditional US, CT, AFP level measurement and other methods, or by biological markers such as GPC-3, micro-RNA, and detection of some specific cell signal factors. Precision treatment is often carried out with a personalized treatment plan for the patient and a targeted therapy at the molecular level.
Studying potential PKCδ loss of function mutation and its downstream effects in gastric cancer progression
Authors: Guo Xingyu
Published: June 2021

PKC isozymes are involved in the modulation of cellular pathways related with tumor progression, acting as a suppressor or promoter. In cancer cells, PKCs are mutated, and most common type is loss of function. This paper focuses on the effect of PKCδ mutation in gastric cancer. LOF mutation occurs throughout catalytic and kinase domains of PKCδ, disrupting activation and function of kinase. In catalytic domain, there are various potential mutation targets, such as binding groove and zinc finger. Mutation residues detected in the kinase domain, such as DFG and APE motifs, can alter catalytic function, causing interruption of activation. Also, a critical region, called hinge region, modulates caspase-3 dependent cleavage, and such tyrosine mutation in this region reduces cleavage activity, inhibiting fully activation of kinase. Importantly, LOF mutation affects cellular activity of downstream protein, p53, through inhibiting transcription, localization, and phosphorylation. For instance, C1 domain mutant suppresses binding capacity with p53, reducing transcription of p53. Disruption of cellular component, tight junction, assembling related to PKC mutation. As identified, PKCδ correlates with ZO-1, and LOF mutation prevent translocation of ZO-1 to TJ area, leading to errors in TJ assembling, promoting tumor invasion.
The Research of Three Regions Acquisition and Analysis System of Pulse Based on Flexible Sensor
Authors: Shilei Xue , Zhao Hao , Ying An , Kun Huang
Published: June 2021

The objectification of pulse diagnosis is very important to the development and inheritance of TCM, the first step is how to collect more abundant and comprehensive pulse information quickly, reduce the threshold of users for using pulse diagnosis equipment. The existing pulse diagnosis equipment has some limitations, such as single acquisition site, complex compression form and serious dependence on professionals for correcting-pulse position selection. Therefore, a three-pulse diagnosis system based on flexible sensor is designed, which uses a new type of flexible sensor as the data acquisition port, combined with upper computer software and lower computer software to achieve goals of intelligent decompression and data acquisition from Cun, Guan, Chi. The equipment not only greatly reduces the difficulty for users to find correct pulse position identification, but also collect non-destructive pulse information, which provides a new acquisition mode for the pulse diagnosis instrument.
The association of serum selenium with serum lipids in US adults
Authors: Wen Nuan
Published: June 2021

High selenium concentrations were associated with cardiovascular diseases, type 2 diabetes, and central nervous disorders. The author examined the relation of serum selenium concentration with serum lipids levels with the use of the National Health and Nutrition Examination Survey (NHANES) 2017-2018. 759 adults aged more than 20 years old from NHANES 2017-2018 were examined in the analysis. Serum selenium was measured by mass spectrometry. Triglyceride, HDL cholesterol, and total cholesterol were measured through enzymatical methods. LDL cholesterol was calculated then. Comparing Q4 to Q1 of serum selenium, the multivariable adjusted average differences (95% CI) in triglyceride, HDL cholesterol, LDL cholesterol, and total cholesterol were 21.3 mg/dL (9.1, 33.4 mg/dL), 2.3 mg/dL (-0.6, 5.2 mg/dL), 6.3 mg/dL (-1.3, 13.9 mg/dL), 12.8 (95% CI: 4.2, 21.5 mg/dL), respectively. Hence, The increasing serum selenium concentration is associated with increasing triglyceride, total cholesterol, HDL cholesterol, and LDL cholesterol among US adults.
The Power of Using Novel Nanopore Sequencing Technology for Diagnosis, Genomic and Pathological Studies of Covid-19
Authors: Du Chenghao
Published: June 2021

The novel coronavirus disease 2019 (COVID‐19), originally identified in December 2019 Wuhan, China, has propagated to worldwide pandemic, causing many cases of death and morbidity. Since the development of COVID-19 vaccines is still under experimental stages without public access, different types of testing and detection ensuring rapid and accurate results are urgently required to prevent delaying isolation of infected patients. The traditional diagnostic and analytical methods of COVID-19 relied heavily on nucleic acid and antibody-antigen methods but are subject to assembly bias, restricted by reading length, showed some false positive/negative results and had a long turnaround time. Hence, three styles of nanopore sequencing techniques as complementary tools for COVID-19 diagnosis and analysis are introduced. The long-read nanopore sequencing technology has been adopted in metagenomic and pathological studies of virosphere including SARS-CoV-2 recently by either metagenomically, directly or indirectly sequencing the viral genomic RNA of SARS-CoV-2 in real-time to detect infected specimens for early isolation and treatment, to investigate the transmission and evolutionary routes of SARS-CoV-2 as well as its pathogenicity and epidemiology. In this article, the Nanopore-Based Metagenomic Sequencing, Direct RNA Nanopore Sequencing (DRS), and Nanopore Targeted Sequencing (NTS) become the main focus of the novel COVID-19 detecting analytical methods in sequencing platforms, which are discussed in comparison with other traditional and popular diagnostic methods. Finally, different types of nanopore sequencing platforms that are developed by Oxford Nanopore Technologies (ONT) due to various purposes and demands in viral genomic research are briefly discussed.
Essential oils for the treatment of dust mites
Authors: Fu Qing-ming , Zeng Bin , Xiao Qing-yue , He Bin-sheng , Huang Chun-xia , Bao Mei-hua
Published: June 2021

House mites, including D. pteronyssinus and D. farina, are common causes of allergic diseases, such as asthma, atopic dermatitis, eczema, conjunctivitis and perennial rhinitis in susceptible patients. Conventional acaricides, such as benzyl benzoate, bifenthrin, chlorpyrifos are effective chemicals in treating mites. However, they are usually with high drug resistance and high adverse effects on environment, human health, and non-target organisms. Recently, essential oils from different plants were found to be safe and effective alternatives for killing different types of mites. The present review summarized the essential oils from different plants. The crude essential oils from Melissa officinalis, S.lavandulifolia oil, cade oil, P. cattleianum, Patchouli oil, Horseradish oil, C. cassia, P. cablin, Manuka oil, Clove Bud oil, and the pure essential oils, such as eugenol, caryophyllene, and camphor might be good candidates for the dust mites. Further studies on biological mechanisms of the acaricidal effects of these active essential oils, and the structure-activity relationships are needed to make the functions of these drugs more clear.
Application Value of Bedside Ultrasound in the Positioning of PICC Tips in Preterm Infants
Authors: Jiao Yuting , Wu Yumei , Yang Zhi
Published: June 2021

Objective To investigate the application value of bedside ultrasound in the localization of the tip of a Peripherally Inserted Central Catheter (PICC) in preterm infants. Methods 52 preterm infants underwent bedside ultrasound and bedside X-ray examination. Observing the position of the catheter tip, and using the bedside X-ray positioning as the gold standard. Statistics of the incidence of PICC tip normal position and ectopic position showed by bedside ultrasound, and comparing the difference between the results of bedside ultrasound and bedside X-ray. Calculating the accuracy, sensitivity, and specificity of ultrasound in diagnosing the tip position, and the length of the inlet and withdrawal tubes of the ectopic catheter was observed and calculated by ultrasound and down-regulated to the appropriate position under ultrasound guidance. Results The display rate of catheter tip by bedside color Doppler ultrasound was 98.0%, and the accuracy rate of tip position was 90.2%. There was no significant difference compared with bedside X-ray (P = 0.375), and the tip position of the two examination methods was highly consistent (Kappa = 0.769, P<0.001). The sensitivity of diagnosing tip ectopy was 76.5% and the specificity was 97.1%, and the success rate of ectopic catheters in ultrasound-guided downsetting was 100%. Conclusion Bedside ultrasound accurately show the position of the catheter tip and guide the entry and withdrawal of ectopic catheter, with high sensitivity and specificity, which has high value of clinical promotion.
Position of posterior superior alveolar artery in relation to the maxillary sinus using cone beam computed tomography in Indian sub-population
Authors: Godil Aamir Zahid , Devadiga Trupti Jagannath , Supnekar Shraddha Chandrashekhar , Kazi Arshi Ilyas , Wadwan Sanaa Akhlaq , Dugal Ramandeep
Published: June 2021

Purpose: To assess the location of posterior superior alveolar artery (PSAA) using CBCT in relevance to sinus lift procedure for implant placement. Patients and Methods: A retrospective study was conducted using the CBCT data of 500 patients (n = 500). Linear measurements were carried out to localize the medio-lateral and vertical position of posterior superior alveolar artery in postero-lateral wall of maxillary sinus and its proximity to the floor of maxillary sinus using CS 3D imaging 3.7.0 software program. The relative position of PSAA was determined as; (a) intra-osseous, (b) below the membrane and (c) outer-cortex of lateral sinus wall. The location of PSAA was assessed in molar region bilaterally by using following radiographic measurement; (1) distance between the lower border of posterior superior alveolar artery and alveolar crest, (2) height from the floor of maxillary sinus to alveolar crest and (3) distance from the posterior superior alveolar artery to medial wall of maxillary sinus. Results: The prevalence of the artery was observed in 99.4% of the sinuses and was mostly intraosseous (84.2%).The mean distance between the lower border of the artery and alveolar crest is significantly higher in males compared to females (P < 0.01). The distribution of artery location did not differ significantly across various age groups (P > 0.05). Discussion/Conclusion: The most common variant of PSAA was identified in the intra-osseous region and the mean distance of the vessel to crest of the residual ridge differs significantly with gender and not with age.
Maxillary extrafollicular adenomatoid odontogenic tumor: root resorption and involvement of the maxillary sinus and nasal cavity
Authors: Niccolò Lombardi , Daniela Sorrentino , Arianna Bianchi , Andrea Nicali , Laura Moneghini , Marco Cucurullo , Dimitri Rabbiosi
Published: June 2021

Adenomatoid odontogenic tumor (AOT) is a benign, slow-growing lesion and it is considered the fourth most common odontogenic tumor. AOT affects more frequently the young subjects with a predilection for the second and third decades of life. We present here the case of a 36-year-old man affected by large extrafollicular AOT which caused roots resorption of multiple teeth. The lesion involved the entire right maxillary bone and extended into the right maxillary sinus up to the orbital floor and the nasal cavity. Intra-oral surgical excision of the AOT and functional endoscopic sinus surgery led to complete clinical healing in absence of local recurrences.
Diastereoselective Synthesis of Morpholine Derivatives from Grignard Reagents and N-Sulfinyl Imines
Authors: Bateman Joseph M. , Chan Diana , Moroglu Mustafa , Rahemtulla Benjamin F. , Talbot Eric P. A.
Published: June 2021

The stereoselective synthesis of substituted morpholine derivatives has been achieved through a two-step process involving diastereoselective addition of a Grignard reagent to a sulfinyl imine, followed by cyclization.
Personal Protective Equipment-Related Nasal Bridge Folliculitis in a Corona Warrior
Authors: Sharma Rajeev , Bindra Ashish , Soni Kapil Dev
Published: June 2021

Nasal bridge is a common site suffering personal protective equipment-induced skin damages over face among first-line health care workers in this coronavirus disease 2019 pandemic. We hereby report folliculitis as a complication following regular use of N95 respirator and goggles, unreported in literature till now.
Ensure an “Ultrasound Window” on the Patient's Neck to Evaluate Cerebral Blood Flow!
Authors: Yamamoto Tomohiro , Mishima Takehito , Shiraishi Shuichi , Saito Takeshi , Schindler Ehrenfried
Published: June 2021

Near-infrared spectroscopy (NIRS) does not provide information about changes in oxygenation in whole-brain areas. Although the branching vessels of the aortic arch are not always easy to identify using transesophageal echocardiography (TEE), the blood flow status of cervical arteries can always be assessed by applying an ultrasound probe via the “ultrasound window” on the patient's neck, which can be ensured by devising alternative insertion approaches of the central venous catheter. This method is very simple but compensates for the limitations of the combination of NIRS and TEE, especially during cardiac surgery with cardiopulmonary bypass management using selective cerebral perfusion.
Contemporary Clinical Use of Aspirin: Mechanisms of Action, Current Concepts, Unresolved Questions, and Future Perspectives
Authors: Christiansen Mikael , Grove Erik Lerkevang , Hvas Anne-Mette
Published: June 2021

The ability of aspirin to inhibit platelet aggregation has positioned this agent within the most frequently used drugs worldwide. The aim of this article is to review the contemporary clinical use of aspirin and also to discuss unresolved issues not yet translated into clinical practice. Results from several clinical trials have led to strong guideline recommendations for aspirin use in the acute management and secondary prevention of cardiovascular disease. On the contrary, guidelines regarding aspirin use as primary prevention of cardiovascular disease are almost conservative, supported by recent trials reporting that the bleeding risk outweighs the potential benefits in most patients. In pregnancy, aspirin has proved efficient in preventing preeclampsia and small-for-gestational-age births in women at high risk, and is hence widely recommended in clinical guidelines. Despite the vast amount of clinical data on aspirin, several unresolved questions remain. Randomized trials have reported that aspirin reduces the risk of recurrent venous thromboembolism, but the clinical relevance remains limited, because direct oral anticoagulants are more effective. Laboratory studies suggest that a twice-daily dosing regimen or evening intake may lead to more efficient platelet inhibition, and the potential clinical benefit of such strategies is currently being explored in ongoing clinical trials. Enteric-coated formulations of aspirin are frequently used, but it remains unclear if they are safer and as efficient as plain aspirin. In the future, aspirin use after percutaneous coronary interventions might not be mandatory in patients who also need anticoagulant therapy, as several trials support shorter aspirin duration strategies. On the other hand, new treatment indications for aspirin will likely arise, as there is growing evidence that aspirin may reduce the risk of colorectal cancer and other types of cancer.
Anti-Xa Monitoring of Low-Molecular-Weight Heparin during Pregnancy: A Systematic Review
Authors: Kjaergaard Amalie Baun , Fuglsang Jens , Hvas Anne-Mette
Published: June 2021

Low-molecular-weight heparin (LMWH) is commonly used for preventing or treating venous thromboembolic disease (VTE) during pregnancy. The physiological changes in maternal metabolism have led to discussions on optimal LMWH dosing strategy and possible need for monitoring. The aim of this systematic review is to summarize and discuss whether LMWH dose adjustment according to anti-Xa provides superior effectiveness and safety compared with weight adjusted or fixed dosed LMWH in pregnant women. A systematic literature search was performed in PubMed, Embase, and Scopus on September 26, 2020. The study is reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Effectiveness was defined as episodes of thrombosis and safety as bleeding episodes. In total, 33 studies were included: 4 randomized controlled studies and 29 cohort studies. Prophylactic dosing strategies employing weight dosed, fixed dosed, or anti-Xa adjusted LMWH dosing performed equal in effectiveness and safety. In pregnant women with VTE or high thromboembolic risk, therapeutic weight–adjusted LMWH and weight plus anti-Xa-adjusted LMWH provided equal results in terms of effectiveness and safety. Pregnant women with mechanical heart valves (MHVs) received therapeutic anti-Xa-adjusted LMWH with four out of seven studies presenting mean peak anti-Xa within target ranges. Still, pregnant women with MHV experienced both thrombosis and bleeding with anti-Xa in target. Based on the results of this systematic review, current evidence does not support the need for anti-Xa monitoring when using LMWH as thromboprophylaxis or treatment during pregnancy. Nonetheless, the need for anti-Xa monitoring in pregnant women with MHV may need further scrutiny.
Chemotherapy-Induced Nausea and Vomiting in Gastrointestinal Cancer Patients: Do We Need to Revisit Guidelines?
Authors: Kapoor Akhil , Jain Ashutosh , Sharma Abhishek , Shah Minit , Chinthala Shravan , Nandhana Ravindra , Bhargava Prabhat , Ramaswamy Anant , Srinivas Sujay , Ostwal Vikas
Published: June 2021

Purpose The objective of this study was to assess the proportion of patients developing chemotherapy-induced nausea and vomiting (CINV) after receiving chemotherapy for gastrointestinal (GI) cancers, despite receiving antiemetic prophylaxis (AEP) as per the standard guidelines.

Patients and Methods Between April 2019 and March 2020, all patients planned for chemotherapy were eligible for enrolment in the study. The primary endpoint of the study was the assessment of complete response (CR) rates.

Results Overall, 1,276 consecutive patients were screened for this study, while 738 patients fulfilling the eligibility criteria were included. A total of 23.2% of the whole cohort failed to achieve CR. Also, 28.2, 16.9, and 16.6% of patients receiving moderately emetogenic chemotherapy (MEC), low emetogenic chemotherapy (LEC), and high emetogenic chemotherapy (HEC), respectively, failed to achieve CR. The differences in failure to achieve CR was statistically significant between MEC and HEC (p < 0.001) groups. Among MEC group, there was no difference between those who received oxaliplatin (27.8%) versus nonoxaliplatin regimens (25.8%) in terms of failure rates (p = 0.613).

Conclusion Approximately one-fourth of patients failed to achieve a complete response from CINV in GI cancers despite using guideline-based AEP. Patients receiving MEC had the highest failure rates suggesting a need to improve AEP in these patients.
Toward a Liver Cell Atlas: Understanding Liver Biology in Health and Disease at Single-Cell Resolution
Authors: Ma Lichun , Khatib Subreen , Craig Amanda J. , Wang Xin Wei
Published: June 2021

Single-cell technologies are revolutionizing our understanding of cellular heterogeneity and functional diversity in health and disease. Here, we review the current knowledge and advances in liver biology using single-cell approaches. We focus on the landscape of the composition and the function of cells in a healthy liver in the context of its spatial organization. We also highlight the alterations of the molecular landscape in chronic liver disease and liver cancer, which includes the identification of disease-related cell types, altered cellular functions, dynamic cell–cell interactions, the plasticity of malignant cells, the collective behavior of a cell community, and microenvironmental reprogramming. We anticipate that the uncovered liver cell atlas will help deciphering the molecular and cellular mechanisms driving a healthy liver into a disease state. It also offers insight into the detection of new therapeutic targets and paves the way for effective disease interventions.
Real time mapping of methyl iodide dissociation at a conical intersection
Authors: Green Leigh Ann
Published: June 2021

Using attosecond transient absorption spectroscopy, the state-switching dynamics and coherent nuclear motion in polyatomic molecules is mapped in real time.
Two-color scattering for the measurement of neutrals at the edge of fusion devices
Authors: Feng David , Diallo Ahmed , Shneider Mikhail N.
Published: June 2021

Laser two-color scattering (TCS) is proposed to detect the neutral species in the edge of fusion devices, namely, tokamaks. TCS uses two wavelengths to probe both the laser Rayleigh scattering and Thomson scattering of the neutral-electron bath, with emphasis on neutral density measurements such as that of hydrogen and deuterium. Modeling of the Rayleigh scattering of tokamak neutral species under various plasma conditions (electron density and temperature) shows that, with an appropriate filtering of the Thomson signal and by going to ultraviolet-region wavelengths, identification of the Rayleigh signal can be achieved. Photon count and signal fractions are calculated in two test cases, one in the midplane region of the National Spherical Torus Experiment and one in the divertor region of DIII-D. An uncertainty analysis and discussion of the feasibility of the TCS diagnostic is also presented.
Multi-keV x-ray radiator from titanium cylindrical cavity at the Shenguang-III prototype laser facility
Authors: Xiong Gang , Zhang Jiyan , Che Xingsen , Qing Bo , Zhang Zhiyu , Li Zhichao , Yu Bo , Zhang Yuxue , Hu Zhimin , Zhao Hang , Wei Minxi , Yuan Zheng , Zhao Yang , Yang Guohong , Song Tianming , Yi Rongqing , Yang Yimeng , Huang Chengwu , Zhu Tuo , Li Yukun , Lv Min , Zhao Yan , Gao Junwen , Zan Xiayu , Hou Lifei , Yu Ruizhen , Jing Longfei , Yi Tao , Dong Yunsong , Yang Dong , Zhou Kaiming , Chen Jinghui , Zeng Chao , Yang Jiamin
Published: June 2021

Great efforts have been made to create a bright K-shell source using the thin metal cylindrical cavities in the past few decades. Several metal materials such as titanium (Ti), iron, and so on have been tested for high x-ray conversion efficiency mainly at the OMEGA and NIF laser facilities. Recently, x-ray sources in Ti K-shell transition energy range were investigated at the Shenguang-III prototype laser facility with ∼5 kJ laser energy. The experiments were aimed to reproduce the previous ones at OMEGA, but with an extraordinarily small volume of cylindrical cavity and detailed characterizations of the x-ray source. The cavities were 800 μm inner diameter, 800 μm length, and 30 μm thick plastic tubes supporting 1 μm thick Ti. Seven laser beams were focused to 200 μm diameter. The combination of the small cavity volume and the focused laser spots is intended to improve the electron temperature with limited laser energy since the electron temperature is a key issue for high x-ray conversion efficiency. Thomson scattering was adopted to experimentally probe the electron temperatures at special time and space zones as well as the average temperature obtained from the Ti K-shell spectrum. The evolutions of the electron temperature and density are predicted by the radiation hydrodynamic simulation. A top view and two photon energy bands of x-ray source images provide a way to directly observe the plasma movement toward the cavity axis and distinguish the different emission mechanisms between the Ti K-shell and lower energy x rays. Six Higher-energy x-ray detectors located at different angles were used to record the Ti K-shell x-ray emission and demonstrate its isotropic feature. The characteristics of the x-ray radiate intensity including the time evolution, the angular distribution, and the total yields for both the photon energy regions above and below 4 keV are compared between the cavity and planar targets. Obviously, different behaviors were found between the two photon energy regions and the two types of targets. The x-ray conversion efficiency of the Ti cylinder was determined to be ∼4% and ∼21% in 4π sr in the Ti K-shell (4–7 keV) and <4 keV range, respectively. The Ti K-shell conversion efficiency obtained in the present experiments is between the ones driven by 13.5 and 4.5 kJ laser energy at OMEGA.
Time-dependent behavior of a Debye sheath: Lengthening and establishment of the stationary state
Authors: Tskhakaya D. D. , Vasileska I. , Kos L.
Published: June 2021

After solving the time-dependent Boltzmann–Vlasov kinetic equation and finding the corresponding particle distribution functions [realized by Tskhakaya et al., Phys. Plasmas 27(1), 023517 (2020)], there is an opportunity to consider various non-stationary-plasma problems. Using these distribution functions, the time evolution of a one-dimensional Debye sheath is investigated. The time dependence of the sheath's lengthening is described, while the characteristic time to establish a stationary Debye sheath is estimated. We show that the sheath's potential reaches a stationary state only when the floating potential condition is fulfilled.
Thermal conductivity measurement of insulating materials up to 1000 °C with a needle probe
Authors: Jannot Yves , Khalifa Dorsaf , Penazzi Léa , Degiovanni Alain
Published: June 2021

The hot wire method is one of the few methods that can be applied to measure the thermal conductivity of materials at 1000 °C and above. However, in the case of granular or electrically conductive materials, the heating wire and thermocouple must be insulated from the material by placing them in a sheath (or a needle). In this case, it is shown that the method of using the slope of the curve T = f[ln(t)] could lead to estimation errors of up to 30% for some materials. A complete quadrupolar model of the system needle/material is developed, and a sensitivity analysis of the probe temperature to the different parameters allowed for the selection of a reduced model, enabling a precise estimation of the thermal conductivity. Measurements carried out between 600 and 1000 °C on a material of known thermal conductivity led to deviations of less than 3%. The method is finally applied up to 1000 °C to two granular materials and to compacted molding sand with quite a good fitting between the experimental and modeled curves.
Near-infrared nanospectroscopy using a low-noise supercontinuum source
Authors: Kaltenecker Korbinian J. , Rao D. S. Shreesha , Rasmussen Mattias , Lassen Henrik B. , Kelleher Edmund J. R. , Krauss Enno , Hecht Bert , Mortensen N. Asger , Grüner-Nielsen Lars , Markos Christos , Bang Ole , Stenger Nicolas , Jepsen Peter Uhd
Published: June 2021

Unlocking the true potential of optical spectroscopy on the nanoscale requires development of stable and low-noise laser sources. Here, we have developed a low-noise supercontinuum (SC) source based on an all-normal dispersion fiber pumped by a femtosecond fiber laser and demonstrate high resolution, spectrally resolved near-field measurements in the near-infrared (NIR) region. Specifically, we explore the reduced-noise requirements for aperture-less scattering-type scanning near-field optical microscopy (s-SNOM), including inherent pulse-to-pulse fluctuation of the SC. We use our SC light source to demonstrate the first NIR, spectrally resolved s-SNOM measurement, a situation where state-of-the-art commercial SC sources are too noisy to be useful. We map the propagation of surface plasmon polariton (SPP) waves on monocrystalline gold platelets in the wavelength region of 1.34–1.75 μm in a single measurement, thereby characterizing experimentally the dispersion curve of the SPP in the NIR. Our results represent a technological breakthrough that has the potential to enable a wide range of new applications of low-noise SC sources in near-field studies.
Drag reduction and transient growth of a streak in a spanwise wall-oscillatory turbulent channel flow
Authors: Yakeno A.
Published: June 2021

The drag-reduction mechanism of spanwise wall oscillation in a turbulent channel was investigated as an extension of the work of Yakeno et al. [“Modification of quasi-streamwise vortical structure in a drag-reduced turbulent channel flow with spanwise wall oscillation,” Phys. Fluids 26, 085109 (2014)] at a low Reynolds number. Flow instability was evaluated by computing the transient energy growth under an oscillating base flow which governed the generation of a near-wall streak structure. Oscillation affected the optimal energy growth of the streak mode, whose characteristics were reasonably consistent with those in a direct numerical simulation. The optimal growth of the tilted-streak mode was enhanced with a thicker Stokes layer under longer oscillation periods, while that of the original streak mode was weakened. The transition of the optimal perturbation under oscillation showed that the spanwise Stokes layer shear contributed considerably more to modification than the spanwise velocity did. A new drag-reduction performance estimation model was suggested using the acceleration of the spanwise velocity shear based on streak formation modification under oscillation, which restrains energy transfer to streamwise vortices via a tilting delay due to oscillation. This simple model worked well even under long oscillation periods and was theoretically consistent with that of Yakeno et al. based on the change in the Reynolds shear stress due to a streamwise vortex at a low Reynolds number.
Antichiral edge states in an acoustic resonator lattice with staggered air flow
Authors: Yu Letian , Xue Haoran , Zhang Baile
Published: June 2021

We present a design to achieve antichiral edge states in acoustic systems where edge states on the two parallel edges of a lattice with a strip geometry propagate in the same direction. This peculiar phenomenon is realized by using a honeycomb lattice consisting of acoustic resonators with staggered air flow; i.e., the air flow takes opposite directions in resonators belonging to different sublattices. The existence of antichiral edge states is revealed through full-wave simulations of the band structure and acoustic fields excited by a point source. Furthermore, we compare these antichiral edge states with conventional chiral edge states. It is found that the antichiral edge states are less robust than the chiral ones. Our work offers new possibilities for dispersion engineering and wave manipulations in acoustics.
Toward modeling of turbulent flow over surfaces of arbitrary roughness
Authors: Brereton G. J. , Jouybari M. Aghaei , Yuan J.
Published: June 2021

The problem of Reynolds-averaged modeling of turbulent boundary-layer flow over surfaces of arbitrary roughness is studied using the results of direct numerical simulations of turbulent flow over many different rough surfaces. The complexity of flow in the roughness sublayer is such that the most effective general strategy appears to be to model it as a prescribed velocity profile, either at a coarse level as a conventional roughness-specific log-linear wall function, or at a fine level as a modeled roughness-specific velocity profile across the roughness sublayer, together with a standard Reynolds-averaged closure in the outer flow. Calculations made with sandgrain roughness wall functions and velocity-profile models were in excellent agreement with channel-flow simulation data and, after correction for effects of Reynolds number and roughness height, were in good agreement with friction coefficients for a wide range of reference pipe-flow data. Equally good predictions of friction coefficients were made of flows over wavy walls, walls with spaced arrays of semi-ellipsoids, and walls with roughness elements of random size and orientation, when either sublayer velocity profiles or wall functions for the corresponding roughnesses were used. This modeling approach is made possible by the availability of relevant data from a library of roughness-sublayer velocity profiles from simulations of flow over many different kinds of rough surfaces.