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PbrARF4 contributes to calyx shedding of fruitlets in ‘Dangshan Suli’ pear by partly regulating the expression of abscission genes
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作者 Guoling Guo Pengfei Wei +5 位作者 Tao Yu Haiyan Zhang Wei Heng Lun Liu Liwu Zhu Bing Jia 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第2期341-354,共14页
Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (... Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit. 展开更多
关键词 PEAR Pyrus bretschneideri Rehd Calyx shedding IAA PbrARF4 Abscission genes
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Load Profile Analysis for Mitigating Load-Shedding in Central Africa: Case of Kinshasa
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作者 Ngondo Otshwe Josue Bin Li +1 位作者 Nawaraj Kumar Mahato Ngouokoua Jaime 《Journal of Power and Energy Engineering》 2024年第8期1-19,共19页
Load shedding is a major problem in Central Africa, with negative consequences for both society and the economy. However, load profile analysis can help to alleviate this problem by providing valuable information abou... Load shedding is a major problem in Central Africa, with negative consequences for both society and the economy. However, load profile analysis can help to alleviate this problem by providing valuable information about consumer demand. This information can be used by power utilities to forecast and reduce power cuts effectively. In this study, the direct method was used to create load profiles for residential feeders in Kinshasa. The results showed that load shedding on weekends results in significant financial losses and changes in people’s behavior. In November 2022 alone, load shedding was responsible for $ 23,4 08,984 and $ 2 80,9 07,808 for all year in losses. The study also found that the SAIDI index for the southern direction of the Kinshasa distribution network was 122.49 hours per feeder, on average. This means that each feeder experienced an average of 5 days of load shedding in November 2022. The SAIFI index was 20 interruptions per feeder, on average, and the CAIDI index was 6 hours, on average, before power was restored. This study also proposes ten strategies for the reduction of load shedding in the Kinshasa and central Africa power distribution network and for the improvement of its reliability, namely: Improved load forecasting, Improvement of the grid infrastructure, Scheduling of load shedding, Demand management programs, Energy efficiency initiatives, Distributed Generation, Automation and Monitoring of the Grid, Education and engagement of the consumer, Policy and regulatory assistance, and Updated load profile analysis. 展开更多
关键词 Statistical Analysis Load Profile Load shedding Kinshasa Distribution Network Distribution Reliability Indices
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Modeling ash deposition and shedding during oxy-combustion of coal/rice husk blends at 70%inlet O_(2)
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作者 Gautham Krishnamoorthy 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第2期196-209,共14页
Co-firing rice husk(RH)and coal with carbon capture using oxy-combustion presents a net carbon negative energy produc-tion opportunity.In addition,the high fusion temperature of the non-sticky,silica rich,RH can mitig... Co-firing rice husk(RH)and coal with carbon capture using oxy-combustion presents a net carbon negative energy produc-tion opportunity.In addition,the high fusion temperature of the non-sticky,silica rich,RH can mitigate ash deposition as well as promote shedding of deposits.To identify the optimum operating conditions,fuel particle sizes,and blend ratios that minimize ash deposition,a Computational Fluid Dynamic methodology with add-on ash deposition and shedding models were employed to predict outer ash deposition and shedding rates during co-combustion of coal/RH in AIR and O2/CO_(2)(70/30 vol%,OXY70)oxidizer compositions.After ensuring that the fly-ash particle size distributions and particle Stokes numbers near the deposition surface were accurately represented(to model impaction),appropriate models for coal ash and RH ash viscosities that were accurate in the temperature region(1200-1300 K)of interest in this study were identified.A particle viscosity and kinetic energy(PKE)based capture criterion was enforced to model the ash capture.An erosion/shed-ding criterion that takes the deposit melt fraction and the energy consumed during particle impact into account was also implemented.Deposition rate predictions as well as the deposition rate enhancement(OXY70/AIR)were in good agreement with measured values.While the OXY70 scenario was associated with a significant reduction(60%-70%)in flue gas velocities,it also resulted in larger fly-ash particles.As a result,the PKE distributions of the erosive RH ash were similar in both scenarios and resulted in similar shedding rates. 展开更多
关键词 CFD OXY-COMBUSTION Ash Deposition shedding CO-FIRING
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Discussion on the Main Reasons for a Large Number of Père David s Deer ( Elaphurus davidianus ) with Abnormal Antler Shedding
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作者 Jinmei XIANG Miaomiao ZHANG +5 位作者 Wenqin CHEN Kai YANG Wenxi WANG Xianrong SONG Nini GUO Chunyun WAN 《Agricultural Biotechnology》 CAS 2023年第5期46-48,共3页
[Objectives]This study was conducted to find out the causes of abnormal antler shedding in Père David s deer(Elaphurus davidianus).[Methods]Abnormally-shed antlers were compared with normally-shed antlers in term... [Objectives]This study was conducted to find out the causes of abnormal antler shedding in Père David s deer(Elaphurus davidianus).[Methods]Abnormally-shed antlers were compared with normally-shed antlers in terms of light condition,antler development and bone nutritional status during the abnormal shedding season in the growth area of Père David s deer.[Results]Abnormally-shed antlers had no significant differences in the development of shed antlers,or even in the overall composition of antlers,from those of normal Père David s deer.[Conclusions]Insufficient light was the main cause of abnormal antler shedding in Père David s deer. 展开更多
关键词 Elaphurus davidianus Antler shedding Development Composition
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Optimal integration of solar home systems and appliance scheduling for residential homes under severe national load shedding
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作者 Sakhile Twala Xianming Ye +1 位作者 Xiaohua Xia Lijun Zhang 《Journal of Automation and Intelligence》 2023年第4期227-238,共12页
In developing countries like South Africa,users experienced more than 1030 hours of load shedding outages in just the first half of 2023 due to inadequate power supply from the national grid.Residential homes that can... In developing countries like South Africa,users experienced more than 1030 hours of load shedding outages in just the first half of 2023 due to inadequate power supply from the national grid.Residential homes that cannot afford to take actions to mitigate the challenges of load shedding are severely inconvenienced as they have to reschedule their demand involuntarily.This study presents optimal strategies to guide households in determining suitable scheduling and sizing solutions for solar home systems to mitigate the inconvenience experienced by residents due to load shedding.To start with,we predict the load shedding stages that are used as input for the optimal strategies by using the K-Nearest Neighbour(KNN)algorithm.Based on an accurate forecast of the future load shedding patterns,we formulate the residents’inconvenience and the loss of power supply probability during load shedding as the objective function.When solving the multi-objective optimisation problem,four different strategies to fight against load shedding are identified,namely(1)optimal home appliance scheduling(HAS)under load shedding;(2)optimal HAS supported by solar panels;(3)optimal HAS supported by batteries,and(4)optimal HAS supported by the solar home system with both solar panels and batteries.Among these strategies,appliance scheduling with an optimally sized 9.6 kWh battery and a 2.74 kWp panel array of five 550 Wp panels,eliminates the loss of power supply probability and reduces the inconvenience by 92%when tested under the South African load shedding cases in 2023. 展开更多
关键词 Load shedding Inconvenience Optimal scheduling and sizing strategies K-Nearest Neighbour(KNN) Multi-objective mixed integer nonlinear optimisation
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Energy Efficiency in Periods of Load Shedding and Detrimental Effects of Energy Dependence in the City of Maroua, Cameroon
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作者 Ngoussandou Bello-Pierre Nicodem Nisso +2 位作者 Dieudonné Kidmo Kaoga Kitmo   Hyacinthe Tchakounté 《Smart Grid and Renewable Energy》 CAS 2023年第4期61-71,共11页
During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance... During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance showed the dependence of the population on these fluctuations, which could be bypassed or suppressed. In most cases, the blackout occurs during high energy demand. In this paper, a method for evaluating electrical efficiency is proposed and its credibility has been demonstrated on the one hand, and on the other hand, a renewable energy production system is proposed. The Homer software has made possible the analysis of the proposed system and its impact on the environment has also been carried out. The techno-economic study of the system has proved that a solar photovoltaic farm associated with an energy storage system, with a capacity of 47 MW, can meet the energy demand of the town of Maroua. This alternative is profitable for this locality which lives in a precarious situation and a continuous need. 展开更多
关键词 Energy Efficiency Load shedding Detrimental Effects Maroua Cameroon
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Pilomatrixoma causing irreversible peripheral eyebrow shedding:A case report
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作者 Zeren Shen Fei Cheng +3 位作者 Yanqin Dai Yijia Yu Lulu Ye Jinghong Xu 《Chinese Journal of Plastic and Reconstructive Surgery》 2023年第1期30-32,共3页
Pilomatrixomas are benign tumors derived from hair stromal cells;however,their exact etiology is unknown.A 31-year-old woman presented with a subcutaneous mass located precisely above the left eyebrow,with shedding of... Pilomatrixomas are benign tumors derived from hair stromal cells;however,their exact etiology is unknown.A 31-year-old woman presented with a subcutaneous mass located precisely above the left eyebrow,with shedding of eyebrow hair around the mass,and the shedding area gradually expanded.Surgical removal of the mass failed to prevent eyebrow loss,and the entire left eyebrow shed 6 months postoperatively.Pathology and histology of the biopsy specimen revealed a pilomatrixoma comprising basaloid cells and ghost cells,with basaloid cells expressing high bcl-2 levels.Instead of apoptosis,the emergence and growth of pilomatrixoma-induced microinflammation around the hair follicles of the eyebrow may lead to eyebrow loss. 展开更多
关键词 PILOMATRIXOMA Eyebrow shedding MICROINFLAMMATION
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Dynamic Characteristics Analysis of Ice-Adhesion Transmission Tower-Line System under Effect of Wind-Induced Ice Shedding 被引量:1
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作者 Yongping Yu Lihui Chen +1 位作者 JuanjuanWang Guoji Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第11期647-670,共24页
The tower line system will be in an unsafe status due to uniform or uneven fall of ice coating which is attached to the surface of tower and lines.The fall of ice could be caused by wind action or thermal force.In ord... The tower line system will be in an unsafe status due to uniform or uneven fall of ice coating which is attached to the surface of tower and lines.The fall of ice could be caused by wind action or thermal force.In order to study the dynamic characteristics of the self-failure of the transmission line under the action of dynamicwind load,a finite elementmodel of the two-span transmission tower line system was established.The birth and death element methods are used to simulate the icing and shedding of the line.Tensile failure strength is the shedding criterion for ice coating.The fluctuating wind speed time history of the tower line systemis first simulated,and then the fluctuating wind and the average wind are superimposed to generate the instantaneous wind speed and converted into wind load.The dynamic response of the transmission tower line systemunder iced coupling with different wind speeds and different thicknesses of ice coating was studied.This is the first attempt that the coupling dynamic response of the icing shedding and wind load for the transmission tower-line system is discussed in this paper.In addition,the dynamic characteristics of wind are included.In particular,the limiting mechanical conditions are considered.According to the simulation results,it is found:because of the ice shedding,the stress of the conductor changes obviously in the first 20 seconds,and the ground wire changes sharply in the first two seconds;the icing of the conductor(ground)wire is gradually deicing under the action of wind vibration;the displacement of tower top increases with the increase of wind speed and icing thickness. 展开更多
关键词 Tower line system fluctuating wind ice shedding dynamic response wind-induced ice shedding
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The transmembrane domain of TACE regulates protein ectodomain shedding 被引量:5
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作者 Xiaojin Li Liliana Pére +1 位作者 Zui Pan Huizhou Fan 《Cell Research》 SCIE CAS CSCD 2007年第12期985-998,共14页
Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme (TACE), which causes the release of their ectodomains. An ADAM (a disintegrin and metalloprotease domain) family member, TACE co... Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme (TACE), which causes the release of their ectodomains. An ADAM (a disintegrin and metalloprotease domain) family member, TACE contains several noncatalytic domains whose roles in ectodomain shedding have yet to be fully resolved. Here, we have explored the function of the transmembrane domain (TM) of TACE by coupling molecular engineering and functional analysis. A TM-free TACE construct that is anchored to the plasma membrane by a glycosylphosphatidylinositol (GPI)-binding polypeptide failed to restore shedding of transforming growth factor-or (TGF-α), tumor necrosis factor-α (TNF-α) and L-selectin in cells lacking endogenous TACE activity. Substitution of the TACE TM with that of the prolactin receptor or platelet-derived growth factor receptor (PDGFR) also resulted in severe loss of TGF-α shedding, but had no effects on the cleavage of TNF-α and L-selectin. Replacement of the TM in TGF-α with that of L-selectin enabled TGF-α shedding by the TACE mutants carrying the TM of prolactin receptor and PDGFR. Taken together, our observations suggest that anchorage of TACE to the lipid bilayer through a TM is required for efficient cleavage of a broad spectrum of substrates, and that the amino-acid sequence of TACE TM may play a role in regulatory specificity among TACE substrates. 展开更多
关键词 transmembrane domain TACE/ADAM17 ectodomain shedding transforming growth factor-α tumor necrosis factor-α L-SELECTIN
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Effect of perforation on flow past a conic cylinder at Re=100:vortex-shedding pattern and force history 被引量:4
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作者 L.M.Lin X.F.Zhong Y.X.Wu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2018年第2期238-256,共19页
The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the hole... The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the holes. The effects of the perforated conic shroud on the vortex shedding pattern in the near wake was mainly investigated, as well as the time history of the drag and lift forces. In the investigated parameter space, three flow regimes were generally identified, corresponding to weak, moderate, and strong disturbance effects.In regime I, the wake can mainly be described by alternately shedding Kármán or Kármán-like vortices. In regime II, the spanwise vortices are obviously disturbed along the span due to the appearance of additional vorticity components and their interactions with the spanwise vortices, but still shed in synchronization along the spanwise direction. In regime III,the typical Kármán vortices partially or totally disappear,and some new vortex shedding patterns appear, such as-type, obliquely shedding, and crossed spanwise vortices with opposite sign. Corresponding to these complex vortex shedding patterns in the near wake, the fluid forces no longer oscillate regularly at a single vortex shedding frequency, but rather with a lower modulation frequency and multiple amplitudes. An overview of these flow regimes is presented. 展开更多
关键词 Vortex shedding pattern Fluid forces Flow control Conical shroud PERFORATION
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Virus load and virus shedding of SARS-CoV-2 and their impact onpatient outcomes 被引量:2
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作者 Pei-Fen Chen Xia-Xia Yu +13 位作者 Yi-Peng Liu Di Ren Min Shen Bing-Sheng Huang Jun-Ling Gao heng-Yang Huang Ming Wu Wei-Yan Wang Li Chen Xia Shi Zhao-Qing Wang Ying-Xia Liu Lei Liu Yong Liu 《World Journal of Clinical Cases》 SCIE 2020年第24期6252-6263,共12页
BACKGROUND Understanding a virus shedding patterns in body fluids/secretions is importantto determine the samples to be used for diagnosis and to formulate infectioncontrol measures.AIM To investigate the severe acute... BACKGROUND Understanding a virus shedding patterns in body fluids/secretions is importantto determine the samples to be used for diagnosis and to formulate infectioncontrol measures.AIM To investigate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)shedding patterns and its risk factors.METHODS All laboratory-confirmed coronavirus disease 2019 patients with completemedical records admitted to the Shenzhen Third People’s Hospital from January28, 2020 to March 8, 2020 were included. Among 145 patients (54.5% males;median age, 46.1 years), three (2.1%) died. The bronco-alveolar lavage fluid(BALF) had the highest virus load compared with the other samples. The viralload peaked at admission (3.3 × 108 copies) and sharply decreased 10 d afteradmission.RESULTS The viral load was associated with prolonged intensive care unit (ICU) duration.Patients in the ICU had significantly longer shedding time compared to those inthe wards (P < 0.0001). Age > 60 years [hazard ratio (HR) = 0.6;95% confidenceinterval (CI): 0.4-0.9] was an independent risk factor for SARS-CoV-2 shedding,while chloroquine (HR = 22.8;95%CI: 2.3-224.6) was a protective factor.CONCLUSION BALF had the highest SARS-CoV-2 load. Elderly patients had higher virus loads,which was associated with a prolonged ICU stay. Chloroquine was associatedwith shorter shedding duration and increased the chance of viral negativity. 展开更多
关键词 COVID-19 Virus shedding Viral load Patient outcome China Infectious disease
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INVESTIGATION OF VORTEX SHEDDING INDUCED HYDRODYNAMIC VIBRATION IN VORTEX STREET FLOWMETER 被引量:2
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作者 Fu Xin,Xu Bing,Yang Huayong (State Key Laboratory of Fluid Power Transmission and Control,Zhejiang University) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2001年第4期310-313,共4页
Vortex street flowmeter has been used in steady flow measurement for about three decades The benefits of this type of flowmeter include high accuracy,good linearty,wide measuring range,and excellent reliability Ho... Vortex street flowmeter has been used in steady flow measurement for about three decades The benefits of this type of flowmeter include high accuracy,good linearty,wide measuring range,and excellent reliability However,in unsteady flow measurement,the pressure disturbance as well as the noise from the system or surrounding can reduce the signal to noise ratio of the flowmeter seriously Aimed to use vortex street flowmeters in unsteady flow measurement,the characteristics of the vortex shedding induced hydrodynamic vibration around the prism bluff body in a vortex street flowmeter are investigated numerically and by expriments The results show that the hydrodynamic vibrations with 180° phase shift occur at the axisymmetric points of the channel around the bluff body The most intense vibration occurs at the points on the lateral faces close to the base of the prism The results provide therefore a useful reference for developing an anti interference vortex flowmeter using the different ial sensing technique. 展开更多
关键词 Vortex street flowmeter Vortex shedding induced hydrodynamic vibration Unsteady flow measurement Anti-interference performance
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Role of ADAM10 and ADAM17 in CD16b Shedding Mediated by Different Stimulators 被引量:2
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作者 Sha Guo Min Peng +1 位作者 Qing Zhao Wei Zhang 《Chinese Medical Sciences Journal》 CAS CSCD 2012年第2期73-79,共7页
Objective To investigate the main proteinases responsible for CD16b shedding under different stimulators. Methods HEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then ... Objective To investigate the main proteinases responsible for CD16b shedding under different stimulators. Methods HEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then overexpressed with a disintegrin and metalloproteinase 10 (ADAM10) or ADAM17, sup- pressed with short hairpin RNA of ADAM10 or ADAM I 7, and reconstituted with ADAM 10 or ADAM17, respectively. After each treatment, the cell line was stimulated with ionomycin or phorbol 12-myristate- 13-acetate (PMA) for 12 hours. The soluble CD 16b released from cell membrane was detected by immuno- precipition and immunoblot. Quantitation was then implemented to compare the amount of soluble CD 16b in cell supernatant after stimulation. Results HEK293 cell line stably expressing CD16b was successfully established. When CDI6b ex- pressing cell line was overexpressed with ADAM 10, shedding of CD 16b was increased after stimulation with ionomycin but not PMA; when the cell line overexpressed with ADAM I7, shedding of CDI6b was increased after stimulation with PMA but not ionomycin. Similarly, when ADAM10 was suppressed by short hairpin RNA, CD 16b shedding was decreased after stimulation with ionomycin; when ADAM 17 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with PMA. The shedding of CD16b was increased again when CD16b expressing cell line was reconstituted with ADAM10 and stimulated by ionomycin or reconstituted with ADAM 17 and stimulated by PMA. Conclusions Both ADAM10 and ADAM17 could shed CD16b, but they possess differed prefer- ences. ADAM10 is the main sheddase under stimulation of ionomycin, while ADAM17 is the main sheddase under stimulation of PMA. 展开更多
关键词 a disintegrin and metalloproteinase 10 a disintegrin and metalloproteinase 17 CD 16b shedding
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Inhibitory role of TACE/ADAM17 cytotail in protein ectodomain shedding 被引量:2
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作者 Liliana Pérez 《World Journal of Biological Chemistry》 CAS 2011年第11期246-251,共6页
AIM:To determine if the cytotail of the principal sheddase tumor necrosis factor-α converting enzyme (TACE;ADAM17) controls protein ectodomain shedding.METHODS:Site-directed mutagenesis was performed to derive TACE v... AIM:To determine if the cytotail of the principal sheddase tumor necrosis factor-α converting enzyme (TACE;ADAM17) controls protein ectodomain shedding.METHODS:Site-directed mutagenesis was performed to derive TACE variants. The resulting TACE expression plasmids with amino acid substitutions in the extracel-lular,cysteine-rich disintegrin domain (CRD) and/or deleted cytotail,along with an expression vector for the enhanced green fluorescence protein were transfected into shedding-defective M1 mutants stably expressing transmembrane L-selectin or transforming growth factor (TGF)-α. The expression levels of the TACE substrates at the cell surface were determined by flow cytometry. RESULTS:Consistent with published data,a single point mutation (C600Y) in the CRD led to shedding defi-ciency. However,removal of the cytotail from the C600Y TACE variant partially restored ectodomain cleavage of TGF-α and L-selectin. Cytotail-deleted mutants with any other substituting amino acid residues in place of Cys600 displayed similar function compared with tail-less C600Y TACE.CONCLUSION:The cytotail plays an inhibitory role,which becomes evident when it is removed from an enzyme with another mutation that affects the enzyme function. 展开更多
关键词 ADAM17 ECTODOMAIN shedding L-SELECTIN Tumor NECROSIS factor-α converting enzyme
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Experimental Investigation on Cavitating Flow Shedding over an Axisymmetric Blunt Body 被引量:6
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作者 HU Changli WANG Guoyu HUANG Biao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第2期387-393,共7页
Nowadays,most researchers focus on the cavity shedding mechanisms of unsteady cavitating flows over different objects,such as 2D/3D hydrofoils,venturi-type section,axisymmetric bodies with different headforms,and so o... Nowadays,most researchers focus on the cavity shedding mechanisms of unsteady cavitating flows over different objects,such as 2D/3D hydrofoils,venturi-type section,axisymmetric bodies with different headforms,and so on.But few of them pay attention to the differences of cavity shedding modality under different cavitation numbers in unsteady cavitating flows over the same object.In the present study,two kinds of shedding patterns are investigated experimentally.A high speed camera system is used to observe the cavitating flows over an axisymmetric blunt body and the velocity fields are measured by a particle image velocimetry(PIV)technique in a water tunnel for different cavitation conditions.The U-type cavitating vortex shedding is observed in unsteady cavitating flows.When the cavitation number is 0.7,there is a large scale cavity rolling up and shedding,which cause the instability and dramatic fluctuation of the flows,while at cavitation number of 0.6,the detached cavities can be conjunct with the attached part to induce the break-off behavior again at the tail of the attached cavity,as a result,the final shedding is in the form of small scale cavity and keeps a relatively steady flow field.It is also found that the interaction between the re-entrant flow and the attached cavity plays an important role in the unsteady cavity shedding modality.When the attached cavity scale is insufficient to overcome the re-entrant flow,it deserves the large cavity rolling up and shedding just as that at cavitation number of 0.7.Otherwise,the re-entrant flow is defeated by large enough cavity to induce the cavity-combined process and small scale cavity vortexes shedding just as that of the cavitation number of0.6.This research shows the details of two different cavity shedding modalities which is worthful and meaningful for the further study of unsteady cavitation. 展开更多
关键词 cavity shedding unsteady cavitating flows high-speed video camera PIV re-entrant flow
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An unusual COVID-19 case with over four months of viral shedding in the presence of low neutralizing antibodies: a case report 被引量:1
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作者 Wei Chen Zhiliang Hu +5 位作者 Changhua Yi Yun Chi Qingfang Xiong Chee Wah Tan Yongxiang Yi Lin-Fa Wang 《The Journal of Biomedical Research》 CAS CSCD 2020年第6期470-474,共5页
The ongoing coronavirus disease 2019(COVID-19)pandemic is a global public health crisis,causing social and economic disasters in many countries.In China,two-consecutive negative results of nucleic acid tests for SARS-... The ongoing coronavirus disease 2019(COVID-19)pandemic is a global public health crisis,causing social and economic disasters in many countries.In China,two-consecutive negative results of nucleic acid tests for SARS-CoV-2 from the respiratory samples are required to end the quarantine of COVID-19 patients.However,clinicians face a dilemma in case of patients with long-term viral shedding.This report described an unusual COVID-19 case who had persistent viral RNA positivity for more than 4 months after initial illness in the presence of low neutralizing antibodies,but without prolonged clinical symptoms.Multiple anti-viral drug treatments had no impact and there was no evidence of re-infection.When the patient was self-quarantined at home,no infection occurred to the three family members living with her for 15 to 19 days.Sputum viral culture in BSL-3 laboratory on the 102nd day after symptom onset was negative.From the 129th day on,8 continuous nucleic acid tests of sputum samples showed negative results.The patient was discharged on 137th days since symptom onset.In conclusion,viral RNA shedding in the sputum of the COVID-19 patient may last over 4 months.As no evidence shows the existence of infectious virus,two-consecutive negative nucleic acid tests may not be the prerequisite for ending quarantine of COVID-19 patients with prolonged viral shedding. 展开更多
关键词 COVID-19 SARS-CoV-2 VIRAL shedding NEUTRALIZING antibodies QUARANTINE
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High fecal calprotectin levels are associated with SARS-CoV-2 intestinal shedding in COVID-19 patients:A proof-of-concept study 被引量:1
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作者 Verena Zerbato Stefano Di Bella +11 位作者 Mauro Giuffrè Anna Wladyslawa Jaracz Ylenia Gobbo Diego Luppino Paolo Macor Ludovica Segat Raffaella Koncan Pierlanfranco D'Agaro Michael Valentini Lory Saveria Crocé Maurizio Ruscio Roberto Luzzati 《World Journal of Gastroenterology》 SCIE CAS 2021年第22期3130-3137,共8页
BACKGROUND One third of coronavirus disease 2019(COVID-19)patients have gastrointestinal symptoms.Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)RNA has been detected in stool samples of approximately 50%o... BACKGROUND One third of coronavirus disease 2019(COVID-19)patients have gastrointestinal symptoms.Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)RNA has been detected in stool samples of approximately 50%of COVID-19 individuals.Fecal calprotectin is a marker of gastrointestinal inflammation in the general population.AIM To investigate if fecal calprotectin correlates with SARS-CoV-2 intestinal shedding in COVID-19 patients with pneumonia.METHODS Patients with SARS-CoV-2 pneumonia admitted to the Infectious Disease Unit(University Hospital of Trieste,Italy)from September to November 2020 were consecutively enrolled in the study.Fecal samples were collected and analyzed for quantification of fecal calprotectin(normal value<50 mg/kg)and SARS-CoV-2 RNA presence by polymerase chain reaction(PCR).Inter-group differences were determined between patients with and without diarrhea and patients with and without detection of fecal SARS-CoV-2.RESULTS We enrolled 51 adults(40 males)with SARS-CoV-2 pneumonia.Ten patients(20%)presented with diarrhea.Real-time-PCR of SARS-CoV-2 in stools was positive in 39 patients(76%),in all patients with diarrhea(100%)and in more than two thirds(29/41,71%)of patients without diarrhea.Obesity was one of the most common comorbidities(13 patients,25%);all obese patients(100%)(P=0.021)tested positive for fecal SARS-CoV-2.Median fecal calprotectin levels were 60 mg/kg[interquartile range(IQR)21;108];higher fecal calprotectin levels were found in the group with SARS-CoV-2 in stools(74 mg/kg,IQR 29;132.5)compared to the group without SARS-CoV-2(39 mg/kg,IQR 14;71)(P<0.001).CONCLUSION High fecal calprotectin levels among COVID-19 patients correlate with SARSCoV-2 detection in stools supporting the hypothesis that this virus can lead to bowel inflammation and potentially to the‘leaky gut’syndrome. 展开更多
关键词 COVID-19 SARS-CoV-2 OBESITY Fecal calprotectin GUT Viral shedding
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Characteristics of Viral Shedding in Respiratory Samples and Specific Antibodies Production in 564 COVID-19 Patients 被引量:1
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作者 Jing GONG Hui DONG +17 位作者 Ding-kun WANG Fu-er LU Zhao-yi HUANG Ke FANG Wen-ya HUANG Fen YUAN Xing CHEN Qing-song XIA Le-yi MA Fan WU Hao SU Min-min GONG Yue-heng TANG Ke-xin NIE Zhi WANG Sheng-hao TU Ming-min ZHANG Jing-bin LI 《Current Medical Science》 SCIE CAS 2021年第1期46-50,共5页
Positive nucleic acid(NA)results have been found in recovered and discharged COVID-19 patients,but the proportion is unclear.This study was designed to analyze the recurrent positive rate of NA results after consecuti... Positive nucleic acid(NA)results have been found in recovered and discharged COVID-19 patients,but the proportion is unclear.This study was designed to analyze the recurrent positive rate of NA results after consecutively negative results,and the relationship between the specific antibody production and positive NA rate.According to Strengthening the Reporting of Observational Studies in Epidemiology guidelines,data of inpatients in Sino-French New City Branch of Tongji Hospital between Jan.28 and Mar.6,2020 were collected.A total of 564 COVID-19 patients over 14 years old who received the examinations of NA and antibodies against SARS-CoV-2 were included.Days of viral shedding and specific antibodies were recorded and assessed.Among NA tests in respiratory samples(throat swabs,nasopharyngeal swabs,sputum and flushing fluid in alveoli),the patients with all-negative NA results accounted for 17.20%,those with single-positive results for 46.63%,and those with multiple-positive results for 36.17%respectively.Besides,the recurrent positive NA results after consecutively negative results appeared in 66 patients(11.70%).For multiple-positive patients,median viral shedding duration was 20 days(range:1 to 57 days).Of the 205 patients who received 2 or more antibody tests,141(68.78%)had decreased IgG and IgM concentrations.IgM decreased to normal range in 24 patients,with a median of 44 days from symptom onset.Viral shedding duration was not significantly correlated with gender,age,disease severity,changes in pulmonary imaging,and antibody concentration.It is concluded that antibody level and antibody change had no significant correlation with the positive rate of NA tests and the conversion rate after continuous negative NA tests.In order to reduce the recurrent positive proportion after discharge,3 or more consecutive negative NA test results with test interval more than 24 h every time are suggested for the discharge or release from quarantine. 展开更多
关键词 COVID-19 viral shedding specific antibodies
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Comparable outcomes but higher risks of prolonged viral RNA shedding duration and secondary infection in cancer survivors with COVID-19: A multi-center, matched retrospective cohort study 被引量:1
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作者 Hui Peng Sheng Wang +15 位作者 Qi Mei Yuhong Dai Jian Li Ming Li Kathrin Halfter Xueyan Jiang Qin Huang Lei Wang Wei Wei Ru Liu Zhen cao Motuma Yigezu Daba Fangfang Wang Bingqing Zhou Hong Qiu Xianglin Yuan 《Oncology and Translational Medicine》 CAS 2020年第6期237-246,共10页
Results Sixty-one cancer survivors and 183 matched non-cancer patients were screened from 2,828 COVID-19 infected patients admitted to 4 hospitals in Wuhan,China.The median ages of the cancer survivor cohort and non-c... Results Sixty-one cancer survivors and 183 matched non-cancer patients were screened from 2,828 COVID-19 infected patients admitted to 4 hospitals in Wuhan,China.The median ages of the cancer survivor cohort and non-cancer patient cohort were 64.0(55.0–73.0)and 64.0(54.0–73.5),respectively(P=0.909).Cancer survivors reported a higher incidence of symptom onset than non-cancer patients.Fever(80.3%vs.65.0%;P=0.026)was the most prevalent symptom,followed by cough(65.6%vs.37.7%;P<0.001),myalgia,and fatigue(45.9%vs.13.6%;P<0.001).The risks of the development of severe events(adjusted hazard ratio[AHR]=1.25;95%confidence interval[CI]:0.76–2.06;P=0.378)and mortality(relative risk[RR]=0.90,95%CI:0.79–1.04;P=0.416)in the cancer survivor cohort were comparable to those of the matched non-cancer patient cohort.However,the cancer survivor cohort showed a higher incidence of secondary infection(52.5%vs.30.1%;RR=1.47,95%CI:1.11–1.95;P=0.002)and a prolonged viral RNA shedding duration(32 days[IQR 26.0–46.0]vs.24.0 days[IQR 18.0–33.0];AHR=0.54;95%CI:0.38–0.80;P<0.05).Conclusion Compared to non-cancer patients,cancer survivors with COVID-19 exhibited a higher incidence of secondary infection,a prolonged period of viral shedding,but comparable risks of the development of severe events and mortality.It is helpful for clinicians to take tailored measures to treat cancer survivors with COVID-19. 展开更多
关键词 COVID-19 SARS-CoV-2 cancer survivor prognosis viral shedding MORTALITY
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Determination of Effective Load Shedding Schemes in Electric Power Plants 被引量:1
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作者 Godwin Effiong Priye Kenneth Ainah Jackson Karniliyus 《Energy and Power Engineering》 2020年第10期555-567,共13页
The ability of power system to survive the transition from preloading state to the gradual increase in load and thereafter reach an acceptable operational condition is an indication of transient stability of the syste... The ability of power system to survive the transition from preloading state to the gradual increase in load and thereafter reach an acceptable operational condition is an indication of transient stability of the system. The study analyzed load shedding scheme through the use of empirical measurement tools and load-flow simulation techniques. It was geared towards determining effective load shedding strategies to reduce unnecessary overload in order to achieve dynamic stability of the electric power network in the Export Free Trade Zone, Calabar, Nigeria. From the tests and the measurements taken, it was observed that the real and reactive powers from the generator and the mechanical power from the turbine engine were stable when the load shedding controller was switched on, as compared to when it was off. The engine speed, the bus-bar frequency and the output voltage of the generator stabilized within a shorter time (about 8 seconds) when the controller was switched on than when it was on the off condition. Also, there were noticeable fluctuations in the speed of the remaining two generators. It became stable at about 12 seconds after the loss. The variations were 0.3 per cent of the nominal speed value. The excitation voltage fluctuated from 1.2 (pu) to 4.5 (pu) when the bus voltage dipped as a result of additional load. It then came down and stabilized at 1.8 (pu) after few swings. This confirmed that the stability of power system is much enhanced when load shedding controllers are effectively configured on the network. 展开更多
关键词 Power System Transient Stability Load shedding Scheme Electric Power Network
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