Feature Matching via Topology-Aware Graph Interaction Model

Feature matching plays a key role in computer vision. However, due to the limitations of the descriptors, the putative matches are inevitably contaminated by massive outliers.This paper attempts to tackle the outlier filtering problem from two aspects. First, a robust and efficient graph interaction model,is proposed, with the assumption that matches are correlated with each other rather than independently distributed. To this end, we construct a graph based on the local relationships of matches and formulate the outlier filtering task as a binary labeling energy minimization problem, where the pairwise term encodes the interaction between matches. We further show that this formulation can be solved globally by graph cut algorithm. Our new formulation always improves the performance of previous localitybased method without noticeable deterioration in processing time,adding a few milliseconds. Second, to construct a better graph structure, a robust and geometrically meaningful topology-aware relationship is developed to capture the topology relationship between matches. The two components in sum lead to topology interaction matching(TIM), an effective and efficient method for outlier filtering. Extensive experiments on several large and diverse datasets for multiple vision tasks including general feature matching, as well as relative pose estimation, homography and fundamental matrix estimation, loop-closure detection, and multi-modal image matching, demonstrate that our TIM is more competitive than current state-of-the-art methods, in terms of generality, efficiency, and effectiveness. The source code is publicly available at http://github.com/YifanLu2000/TIM.

microRNAs与角膜新生血管

正常角膜的无血管化状态能够维持角膜的免疫赦免和透明性,角膜处于富含血管的环境中却能保持无血管化,归因于内源性血管抑制因子。microRNAs(miRs)是一类内源性小分子非编码RNA,在角膜新生血管形成过程中,多种miRs发挥重要的调控作用,是重要的内源性血管抑制因子。本文就miRs在角膜新生血管中的相关研究进行综述,以期为角膜新生血管的治疗和进一步研究提供借鉴。

MicroRNA-433在非小细胞肺癌A549细胞增殖及迁移中的作用

目的研究microRNA-433(miR-433)对人非小细胞肺癌(NSCLC)A549细胞增殖及迁移的作用。方法采用实时聚合酶链反应(real-time PCR)检测miR-433在A549、NCI-H1299、NCI-H358以及人肺成纤维细胞系HFL1中的表达。不同浓度mi R-433 mimic转染A549细胞,选取最佳浓度进行后续实验;MTT法检测细胞增殖情况;Transwell检测细胞迁移情况;双荧光素酶报告基因法检测mi R-433与p21活化激酶4(PAK4)的靶向关系;Western blotting检测PAK4、单丝氨酸蛋白激酶1(LIMK1)、磷酸化单丝氨酸蛋白激酶1(p-LIMK1)、丝切蛋白(Cofilin)和磷酸化丝切蛋白(p-Cofilin)的表达。结果与HFL1比较,mi R-433在3种NSCLC中的表达均降低。过表达miR-433 48 h后,A549细胞增殖和迁移能力降低,差异有统计学意义(P <0.05)。双荧光素酶报告基因法证明PAK4为mi R-433的靶向调节基因,且PAK4在3种NSCLC中的表达均上升。过表达mi R-433后细胞中PAK4、p-LIMK1、p-Cofilin的表达均降低,与mimic control组比较,差异有统计学意义(P <0.05)。结论 mi R-433能通过靶向下调PAK4的表达,抑制LIMK1/Cofilin信号通路,抑制A549细胞的增殖及迁移。

长链非编码RNA ASB16-AS1调控miR-670-3p/ATXN7L3轴影响胃癌细胞增殖、迁移和侵袭

背景多种长链非编码RNA(long non-coding RNA,lncRNAs)在胃癌(gastric cancer,GC)进展中被证实发挥抑癌或促癌作用.但lncRNAs数量众多,仍有多种lncRNAs在GC进展中的作用并不明确.因此,筛选具有影响GC细胞增殖、迁移和侵袭的lncRNAs对GC防治十分必要.目的探讨LncRNA ASB16-AS1调控miR-670-3p/ATXN7L3轴对GC细胞增殖、迁移和侵袭的影响.方法实时荧光定量PCR(real-time quantitative PCR,RTqPCR)和western blot检测人胃黏膜细胞GES-1、GC细胞HGC-27、AGS、NUGC-4中ASB16-AS1、miR-670-3p和ATXN7L3的表达水平.将HGC-27细胞分为si-NC、si-ASB16-AS1、miR-NC、miR-670-3p、si-ATXN7L3、si-ASB16-AS1+anti-miR-NC、si-ASB16-AS1+anti-miR-670-3p、si-ASB16-AS1+pcDNA-NC、si-ASB16-AS1+pcDNA-ATXN7L3组.采用细胞计数试剂盒、transwell实验分别测定细胞活力、迁移侵袭能力;双荧光素酶报告实验、RT-qPCR、western blot确定ASB16-AS1与miR-670-3p、miR-670-3p与ATXN7L3之间的相互作用.结果GC细胞中ASB16-AS1、ATXN7L3呈高表达,miR-670-3p呈低表达(P<0.05).抑制ASB16-AS1表达,或过表达miR-670-3p,或抑制ATXN7L3表达后,HGC-27细胞增殖活力、迁移和侵袭能力均显著降低(P<0.05).ASB16-AS1靶向负调控miR-670-3p表达.miR-670-3p靶向负调控ATXN7L3表达.抑制miR-670-3p表达部分逆转抑制ASB16-AS1对HGC-27细胞增殖、迁移和侵袭的影响(P<0.05).过表达ATXN7L3部分逆转抑制ASB16-AS1对HGC-27细胞增殖、迁移和侵袭的影响(P<0.05).结论抑制ASB16-AS1通过调控miR-670-3p/ATXN7L3轴抑制GC细胞增殖、迁移和侵袭.

Ultrasonography-guided Percutaneous Nephrolithotomy with Chinese One-shot Tract Dilation Technique Based on Stimulated Diuresis:A Report of 67 Cases

The safety and effectiveness of a novel Chinese one-shot dilation technique based on stimulated diuresis for percutaneous nephrolithotomy（PCNL） were investigated.After the feasibility of the Chinese one-shot dilation based on stimulated diuresis was verified by an animal study,this technique was applied in the clinical practice.A total of 67 patients in our department underwent the modified PCNL from July 2014 to June 2015.After the renal infundibulum was distended by stimulated diuresis,the kidney was punctured under the ultrasonographic guidance via the fornix of the target calyx.The working channel was dilated using a special designed pencil-shaped fascial dilator.The successful access rate,nephrostomy tract creation time,pre-and postoperative hemoglobin values and serum creatinine concentrations,stone-free rate and complications were recorded and analyzed.The renal infundibulum was successfully distended in all of the patients by the diuresis treatment.Under the ultrasonographic guidance,the successful access rate was 100% and the mean tract creation time was 2.0 min（range：1.5–5.0 min）.The stone-free rate right after surgery was 91.0%.Although the postoperative hemoglobin was significantly reduced（P〈0.01）,transfusion was not clinically necessary.There was no significant difference in serum creatinine concentrations before and after operation（P〉0.05）.No severe complication occurred during or after the PCNL.It was suggested that this Chinese one-shot dilation technique based on stimulated diuresis is an efficient and safe innovation for PCNL,and is even helpful for those patients with non-dilated pelvicaliceal systems.

Diagnostic and Prognostic Value of Plasma Factor V Activity and Parameters in Thrombin Generation for Disseminated Intravascular Coagulation in Patients with Hematological Malignancies

In this study,we used plasma factor V activity and parameters of the thrombin generation test to discuss their diagnostic and prognostic value for disseminated intravascular coagulation (DIC) in patients with hematological malignancies.A total of 164 patients who were diagnosed with hematological malignancies in the Department of Hematology,Union Hospital,between Apr 2014 and Dec.2014 were enrolled in this study.There were 131 patients in the study group and 33 patients in the control group in terms of the laboratory results for DIC.The patients in the study group were divided into a DIC subgroup (n=59) and a non-DIC subgroup (n=72) based on the International Society of Thrombosis and Hemostasis (ISTH) Integral System,and they were divided into four subgroups [score ≤3 (n=35),score=4 (n=37),score=5 (n=47),and score >6 (n=12)] according to ISTH scores.Using 28-day mortality as the endpoint,the patients in the study group were divided into a survival subgroup (n=111) and a non-survival subgroup (n=20).The results showed that the plasma factor V activity was significantly weaker,and lag time and time to peak were significantly shorter in the study group than in the control group (P<0.01).The factor V activity,peak and endogenous thrombin potential (ETP) were significantly decreased in the DIC subgroup as compared with those in the non-DIC subgroup (P<0.01).Among factor V activity,lag time,peak,ETP,and ttPeak,only the factor V activity was significantly decreased in the nonsurvival subgroup compared with the survival subgroup (P<0.01).With the increase in ISTH score,the ETP and peak decreased gradually.The binary logistic regression analysis revealed that PLT,D-dimer,factor V activity and ETP had linear relationship with DIC diagnosed by ISTH Integral System.Using DIC diagnosed by ISTH Integral System as the endpoint,the area under curve (AUC) of factor V activity was found to be similar to that of blood platelet count (PLT) and prothrombin time (PT).In conclusion,factor V activity,ETP and peak had diagnostic value for DIC in patients with hematological malignancies,and only factor V activity had limited prognostic value.

基于脑-肠轴学说探讨老年功能性消化不良患者睡眠障碍对焦虑抑郁和下消化道症状影响

背景功能性消化不良(functional dyspepsia,FD)是老年患者常见疾病之一,病情容易反复,严重影响患者身心健康.肠-脑互动异常是FD发病主要病因,大多伴有不同程度的睡眠障碍和焦虑、抑郁等负面心理.目前,对于老年FD患者与睡眠障碍和焦虑抑郁、下消化道症状的研究报道较少.目的基于脑-肠轴学说探讨观察老年FD患者睡眠障碍对焦虑抑郁和下消化道症状影响分析.方法选择2017-02/2019-09在我院就诊的236例老年FD患者为研究对象,课题负责人发放量表,对符合罗马Ⅳ标准的老年FD患者进行调查,评估其下消化道症状严重程度,睡眠质量和焦虑和抑郁评分变化情况.结果214例老年FD患者中存在睡眠障碍者103例(48.13%),存在焦虑、抑郁者182例(85.05%).有睡眠障碍老年FD患者的下腹痛发生率为35.92%,下腹不适(非疼痛)发生率为33.98%、羊粪样或硬便发生率为21.36%、用劲排便发生率为32.04%、排便不尽感发生率为43.69%和便急感的发生率为27.18%,均高于无睡眠障碍老年FD患者,差异比较均有统计学意义(P<0.05).有睡眠障碍的老年FD睡眠障碍患者焦虑自评量表评分为65.34分±7.29分,抑郁自评量表评分为66.17分±8.26分,均高于无睡眠障碍的老年FD患者(P<0.05).结论老年FD患者常同时存在睡眠障碍与焦虑、抑郁,睡眠障碍与老年FD患者的下消化道症状关系密切.

Efficacy and Safety of COX-2 Inhibitor Parecoxib for Rigid Cystoscopyrelated Pain Management in Male Patients:A Prospective,Randomized and Controlled Study

Using anesthetic gel may not sufficiently exclude pain perception during and after cystoscopy in male patients.To evaluate the analgesic efficacy and safety of intramuscular parecoxib(40 mg)for outpatient-based rigid cystoscopy,we performed a prospective,randomized and controlled study.Consecutive male patients requiring diagnostic cystoscopy in our hospital were divided into group A(1%tetracaine gel,n=50)and group B(parecoxib,n^5l)at random.Patients received intramuscular injections of either 2 mL sterile saline in group A or 40 mg parecoxib in group B 30 min before the procedure.Tetracaine gel was injected into the urethra 3 min before the procedure in group A,with patients receiving plain lubricant gel in group B at the same time.Cystoscopy-associated pain levels were evaluated using the Visual Analog Score(VAS)during the procedure.Post-procedure urethral pain and complications were recorded and analyzed.The results showed that male patients experienced significantly less pain in group B than in group A(2.70±1.36 V5.3.56±1.74,P=0.008).The percentage of patients with dysuria pain was not significantly different between the two groups.In addition,24 h after cystoscopy,the patients with no previous experience of cystoscopy were more likely to declare urethral pain(59.2%vs.33.3%,P=0.012,relative risk=1.78).No difference was observed in analgesic-related complications between the two groups.We conclude that intramuscular injection of 40 mg parecoxib may improve comfort for male patients undergoing rigid cystoscopy.

Thrombophilia Caused by Beta2-Glycoprotein I Deficiency： In Vitro Study of a Rare Mutation in APOH Gene

This study aimed to explore the mechanism of a novel mutation （p.Lys38Glu） in apolipoprotein H （APOH） gene causing hereditary beta2-glycoprotein I （β2GPI） deficiency and thrombosis in a proband with thrombophilia. The plasma level of β2GPI was measured by ELISA and Western blotting, and anti-β2GPI antibody by ELISA. Lupus anticoagulant （LA） was assayed using the dilute Russell viper venom time. Deficiency of the major natural anticoagulants including protein C （PC）, protein S （PS）, antithrombin （AT） and thrombomodulin （TM） was excluded from the proband. A mutation analysis was performed by amplification and sequencing of the APOH gene. Wild type and mutant （c.112A〉G） APOH expression plasmids were constructed and transfected into HEK293T cells. The results showed that the thrornbin generation capacity of the proband was higher than that of the other family members. Missense mutation p.Lys38Glu in APOH gene and LA coexisted in the proband. The mutation led to β2GPI deficiency and thrombosis by impairing the protein production and inhibiting the platelet aggregation. It was concluded that the recurrent thrombosis of the proband is associated with the coexistence ofp.Lys38Glu mutation in APOH gene and LA in plasma.

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet.In this study,a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays;the model was built and studied using the Geant4 toolkit.The simulation results were compared with the data reported by a radiation assessment detector(RAD).The simulated spectra of neutrons,photons,protons,α particles,and particle groups Z=3-5,Z=6-8,Z=9-13,and Z=14-24 were in a reasonable agreement with the RAD data.However,for deuterons,tritons,and 3He,the simulations yielded much smaller values than for the corresponding RAD data.In addition,the particles’spectra within the 90 zenith angle were also obtained.Based on these spectra,we calculated the radiation dose that would have been received by an average human body on Mars.The distribution of the dose throughout the human body was not uniform.The absorbed and equivalent doses for the brain were the highest among all of the organs,reaching 62.0±1.7 mGy/y and 234.1±8.0 mSv/y,respectively.The average absorbed and equivalent doses for the entire body were approximately 44 mGy/y and 153 mSv/y,respectively.Further analysis revealed that most of the radiation dose was owing to a particles,protons,and heavy ions.We then studied the shielding effect of the Mars soil with respect to the radiation.The body dose decreased significantly with increasing soil depth.At the depth of 1.5 m,the effective dose for the entire body was 17.9±2.4 mSv/y,lower than the dose limit for occupational exposure.At the depth of 3 m,the effective dose to the body was 2.7±1.0 mSv/y,still higher than the accepted dose limit.

Recent developments in HVDC transmission systems to support renewable energy integration

The demands for massive renewable energy integration, passive network power supply, and global energy interconnection have all gradually increased, posing new challenges for high voltage direct current(HVDC) power transmission systems, including more complex topology and increased diversity of bipolar HVDC transmission. This study proposes that these two factors have led to new requirements for HVDC control strategies. Moreover, due to the diverse applications of HVDC transmission technology, each station in the system has different requirements. Furthermore, the topology of the AC-DC converter is being continuously developed, revealing a trend towards hybrid converter stations.

Economic analysis of energy interconnection between Europe and China with 100% renewable energy generation

The economic benefits of interconnecting the power grids of Europe(EU) and China(CN) were assessed considering 100% reliance on renewable energy(RE). Four different scenarios, energy storage without interconnection, installing additional renewable energy sources without interconnection, energy storage with interconnection, and installing additional RE sources with interconnection, were considered for the economic benefit analysis. A comparative study of these four scenarios was conducted to identify the best option for achieving hourly power balance. Further, sensitivity analysis was carried out to demonstrate the robustness of the results. Electricity interconnection between CN and EU decreases the annual additional costs by more than 30% when compared to the absence of interconnection, which demonstrates the necessity and benefits of CN-EU electricity interconnection.

Master-slave wave farm systems based on energy filter with smoothed power output

Wave energy is an important renewable energy source. Previous studies of wave energy conversion(WEC) have focused on the maximum power take-off(PTO) techniques of a single machine. However, there is a lack of research on the energy and power quality of wave farm systems. Owing to the pulsating nature of ocean waves and popular PTO devices, the generated electrical power suffers from severe fluctuations. Existing solutions require extra energy storage and overrated power converters for wave power integration. In this study, we developed a master-slave wave farm system with rotor inertia energy storage; this system delivers self-smoothed power output to the grid and reduces the number of converters. Two control methods based on the moving average filter(MAF) and energy filter(EF) are proposed to smooth the output power of wave farms. RTDS simulations show that the proposed systems and control methods facilitate simple and smooth grid integration of wave energy.

Effects of initial velocity on the sinking of ilmenite-bearing cumulates in the early lunar mantle:Insight from the theory of Rayleigh-Taylor instability

The early lunar mantle overturn,associated with the sinking of the dense ilmenite-bearing cumulate(IBC)crystallized at the shallow lunar mantle,provides satisfactory explanations for the origination of high-Ti basalt,the abnormally strong magnetic field between~3.9 and~3.6 Ga and the low-viscosity zone in the deep lunar mantle,but still poses a debate regarding the initial state of IBC in the early lunar mantle.If the sinking of IBC initiated before the end of lunar magma ocean crystallization,the solidified IBC can acquire a greater thickness and a higher initial velocity at the IBC-mantle boundary.The variation of initial velocity can affect the strain rate of IBC and,correspondingly,the dislocation creep components at the shallow lunar mantle.In this work,we analyze the effects of initial velocity on the dynamics of early lunar mantle by using the theory of Rayleigh-Taylor instability.To couple the effects of diffusion creep and dislocation creep for all major minerals in the lunar mantle,we exploit an improved Minimized Power Geometric(IMPG)model and isostress mixing model to characterize the upper limit and lower limit for the viscosity of the lunar mantle comprising four major minerals,i.e.olivine,orthopyroxene,clinopyroxene and ilmenite.The modeling results suggest that a high initial velocity,in any case,can shorten the onset time,tending to promote the early lunar mantle overturn even in a rheologically-strong lunar mantle.The effect of initial velocity on the overturn wavelength shows a strong dependence on the rheological mixing model.For the isostress mixing model,the increase of initial velocity tends to elongate the overturn wavelength.For the IMPG mixing model,the overturn wavelength is insensitive to the variation of initial velocity.As the actual lunar mantle rheology sandwiches between the rheologies predicted by isostress mixing model and IMPG model,it can be anticipated that the increase of initial velocity tends to elongate the overturn wavelength.In consideration of the importance of the initial velocity on the dynamics of early lunar mantle,future investigations should focus on the dynamics of the solid IBC in the solidifying lunar magma ocean.

Message from the Guest Editor-in-Chief

The potential for renewable energy to make contributions to mitigating the impact of climate change is expected to increase significantly in the longer term.Renewable energy generation technologies including onshore wind,offshore wind,wave,tidal,marine current,and ocean thermal energy generation as well as PV power generation.

Global Mg/Si and Al/Si Distributions on the Lunar Surface Derived from Chang'E-2 X-ray Spectrometer

The technique of X-ray fluorescence remote sensing plays a significant role in research related to the chemical compositions of the Moon. Here we describe the data analysis method for China＇s Chang＇E-2 X-ray spectrometer in detail and present the preliminary results about the first global Mg/Si and Al/Si maps of the lunar surface. Our results show that the distributions of Mg/Si and Al/Si correlate well with terrains on the Moon. The higher Mg/Si ratio corresponds to the mare regions while the lower value corresponds to the highland terrains. The map of the Al/Si ratio shows a reversed distribution compared with the map of the Mg/Si ratio.

Optimal Initialization and Starting Approach of Synchronous Condenser Integrated Power Grid

Synchronous condensers(SCs)are generally used at the receiving-end stations of ultra-high-voltage direct current(UHVDC)transmission systems due to their strong reactive power support and flexible regulation of reactive power according to the interconnected grids operating conditions.In this paper,different starting control schemes of a SC integrated power grid are investigated providing four main contributions:1)The principle of reactive power support of the SC on the interconnected power grid is analytically studied,providing the establishment of mathematical models.2)Four different starting control schemes are developed for the initialization and SC integration,i.e.in Scheme 1,a preset initial falling speed is directly utilized without initialization;in Scheme 2,a black start sequential control approach with a static frequency converter(SFC)is proposed;in Scheme 3,PI/PD/PID controllers are respectively applied for the excitation device at the speed-falling stage;in Scheme 4,a pre-insertion approach of an energy absorption component with R/L/RL is utilized to suppress the surges at the SC integration instant.3)The dynamic behaviors of four different starting schemes at specific operating stages are evaluated.4)The success rate of SC integration is analyzed to evaluate starting control performance.Performance of the SC interconnected system with four different starting control schemes is evaluated in the timedomain simulation environment PSCAD/EMTDC^(TM).The results prove the superiority of the proposed starting control approach in Scheme 4.

An Improved Modulation Strategy for Single-phase Three-level Neutral-point-clamped Converter in Critical Conduction Mode

Two-level totem-pole power factor correction(PFC)converters in critical conduction mode(CRM)suffer from the wide regulation range of switching frequency.Besides,in highfrequency applications,the number of switching times increases,resulting in significant switching losses.To solve these issues,this paper proposes an improved modulation strategy for the single-phase three-level neutral-point-clamped(NPC)converter in CRM with PFC.By optimizing the discharging strategy and switching state sequence,the switching frequency and its variation range have been efficiently reduced.The detailed performance analysis is also presented regarding the switching frequency,the average switching times,and the effect of voltage gain.A 2 k W prototype is built to verify the effectiveness of the proposed modulation strategy and analysis results.Compared with the totem-pole PFC converter,the switching frequency regulation range of the three-level PFC converter is reduced by 36.48%and the average switching times is reduced by 45.10%.The experimental result also shows a 1.2%higher efficiency for the three-level PFC converter in the full load range.

Analysis of China's Electricity Price and Electricity Burden of Basic Industries under the Carbon Peak Target before 2030

The Chinese government is deepening reformation of electricity prices during the 14th Five Year Plan period and has set a carbon emission reduction target of reaching carbon peak before 2030.In this context,will the carbon emission target influence electricity pricing and will electricity price influence competitiveness of Chinese main industries are two questions needing to be answered.This paper compares China's electricity price level with the selected major countries in the world,and four typical industries are selected to evaluate their electricity burden respectively.Then,the correlation between residential electricity price and industrial electricity price and the influencing factors is analyzed,from the perspectives of scale,structure and technology.According to the model obtained by regression analysis,the electricity price level and corresponding residential and industrial electricity burden in 2025 and 2030 are forecasted.Index Terms-Electricity burden,industrial electricity price,regression analysis,residential electricity price.

Comprehensive Optimization-based Techno-economic Assessment of Hybrid Renewable Electricity-hydrogen Virtual Power Plants

Hydrogen is being considered as an important option to contribute to energy system decarbonization.However,currently its production from renewables is expensive compared with the methods that utilize fossil fuels.This paper proposes a comprehensive optimization-based techno-economic assessment of a hybrid renewable electricity-hydrogen virtual power plant(VPP)that boosts its business case by co-optimizing across multiple markets and contractual services to maximize its profits and eventually deliver hydrogen at a lower net cost.Additionally,multiple possible investment options are considered.Case studies of VPP placement in a renewable-rich,congested area of the Australian network and based on real market data and relevant sensitivities show that multi-market participation can significantly boost the business case for cleaner hydrogen.This highlights the importance of value stacking for driving down the cost of cleaner hydrogen.Due to the participation in multiple markets,all VPP configurations considered are found to be economically viable for a hydrogen price of 3 AUD$/kg(2.25 USD$/kg),which has been identified as a threshold value for Australia to export hydrogen at a competitive price.Additionally,if the high price volatility that has been seen in gas prices in 2022(and by extension electricity prices)continues,the flexibility of hybrid VPPs will further improve their business cases.