Jiangsu Niupai Machinery&Elecronics Co,ltd.is National Specialized and New"Little Giant"Enterprise,National High&New Technological Enterprise,Jiangsu Provincial Research Center of Loom Shedding Engin...Jiangsu Niupai Machinery&Elecronics Co,ltd.is National Specialized and New"Little Giant"Enterprise,National High&New Technological Enterprise,Jiangsu Provincial Research Center of Loom Shedding Engineering Technology and Jiangsu Provincial Enterprise Technology Center.The company has obtained SGS-certified ISO9001 quality management system,a globally recognized standard.Niupai specializes in the R&D and manufacturing of cam shedding device,dobby shedding device,jacquard shedding device and heald frames for water-jet looms,air-jet looms as well as rapier looms.展开更多
Changshu Textile Machinery Works Co.,Ltd.was founded in 1958 and is a professional R&D and manufacturing enterprise of looms shedding device in China.The company's products cover three series of shedding devic...Changshu Textile Machinery Works Co.,Ltd.was founded in 1958 and is a professional R&D and manufacturing enterprise of looms shedding device in China.The company's products cover three series of shedding devices for looms(Dobby,Jacquard,Cam Motion),forming a series of products with electronic shedding devices as the main products,and mechanical shedding devices as the auxiliary products.D2876pro electronic dobby The D2876pro electronic dobby is a high-performance equipment designed for a maximum operating speed of 800rpm.It has 16 cams,and 12mm of pitch,with a high installation type.The shedding type is double lift and full clear open.Its maximum wefts is 12,800 and 100,000.It has a two-stage filtration lubrication with a gerotor pump oil recycle system,and it is suitable for water-jet looms.展开更多
A robust Reynolds-Averaged Navier-Stokes(RANS)based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC)rotor.The complex motion with multiple degrees of fr...A robust Reynolds-Averaged Navier-Stokes(RANS)based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC)rotor.The complex motion with multiple degrees of freedom of the Trailing Edge Flap(TEF)is analyzed by employing an inverse nested overset grid method.Simulation of non-rotational and rotational modes of blade motion are carried out to investigate the formation and development of TEF shedding vortex with high-frequency deflection of TEF.Moreover,the mechanism of TEF deflection interference with blade tip vortex and overall rotor aerodynamics is also explored.In nonrotational mode,two bundles of vortices form at the gap ends of TEF and the main blade and merge into a single TEF vortex.Dynamic deflection of the TEF significantly interferes with the blade tip vortex.The position of the blade tip vortex consistently changes,and its frequency is directly related to the frequency of TEF deflection.In rotational mode,the tip vortex forms a helical structure.The end vortices at the gap sides co-swirl and subsequently merge into the concentrated beam of tip vortices,causing fluctuations in the vorticity and axial position of the tip vortex under the rotor.This research concludes with the investigation on suppression of Blade Vortex Interaction(BVI),showing an increase in miss distance and reduction in the vorticity of tip vortex through TEF phase control at a particular control frequency.Through this mechanism,a designed TEF deflection law increases the miss distance by 34.7%and reduces vorticity by 11.9%at the target position,demonstrating the effectiveness of AFC in mitigating BVI.展开更多
The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electr...The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electrothermal de-icing seldom delve into comprehensive ice accretion-melting-deicing models that account for ice shedding.Therefore,the detachment behavior of ice layers during the heating process requires in-depth research and discussion.This paper physically models the phenomenon of ice shedding,incorporates the detachment behavior of ice layers during heating,improves the existing mathematical model for electro-thermal de-icing calculations,establishes an ice accretion-melting-deicing model for electro-thermal de-icing systems,and conducts numerical simulation,verification and optimization analysis of electro-thermal de-icing considering ice shedding.Through multi-condition de-icing numerical simulations of a specific wing model,it is found that ambient temperature can serve as a factor for adapting the electro heating anti/de-icing strategy to the environment.An optimization of heating heat flux density and heating/cooling time is conducted for the wing de-icing control law under the calculated conditions.The improved electrothermal de-icing model and algorithm developed in this paper provide solid technical support for the design of electrothermal de-icing systems.展开更多
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
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
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
Considering the escalating usage of renewa-ble energy and rising frequency of extreme meteorological events,the risk of emergency load shedding(ELS)in power grids due to faults is increasing.The existing ELS strategie...Considering the escalating usage of renewa-ble energy and rising frequency of extreme meteorological events,the risk of emergency load shedding(ELS)in power grids due to faults is increasing.The existing ELS strategies fail to provide users with advance warnings and blackout preparation time.To address this issue,an in-novative strategy called warning and delayed load shed-ding is proposed in this study.In this approach,when it becomes necessary to shed load for emergency control,users are immediately notified with a power outage warning.Subsequently,energy storage and other regula-tory resources are employed to substitute for load shed-ding,thus postponing the execution of the load shedding command.This delay equips users with the ability and time to respond and prepare.To implement this strategy,the operational principles supported by energy storage and backup power are further discussed.Five perfor-mance indexes are utilized to evaluate the delayed load shedding capability.Moreover,the delayed load shedding switch function and energy storage power balance equa-tion are constructed to determine the relationship be-tween energy storage,backup power sources,and load shedding time.Subsequently,two optimized load shed-ding models supported by energy storage are established,i.e.,maximum and flexible delayed models.For compar-ison,improvements are made to the conventional load shedding model without delay by incorporating energy storage.An IEEE 30-node network with energy storage is used to test the three load shedding models.Accordingly,the evaluation indexes are calculated and compared.The results of the performance indexes and comparative analysis validate the effectiveness of the proposed meth-ods,indicating that by using energy storage,users can be notified with advance power outage warnings and prep-aration time.展开更多
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
Vortex-acoustic coupling is one of the most important potential sources of combustion instability in solid rocket motors （SRMs）. Based on the Von Karman Institute for Fluid Dynamics （VKI） experimental motor, the i...Vortex-acoustic coupling is one of the most important potential sources of combustion instability in solid rocket motors （SRMs）. Based on the Von Karman Institute for Fluid Dynamics （VKI） experimental motor, the influence of the thermal inhibitor position and temperature on vortex-shedding-driven pressure oscillations is numerically studied via the large eddy simulation （LES） method. The simulation results demonstrate that vortex shedding is a periodic process and its accurate frequency can be numerically obtained. Acoustic modes could be easily excited by vortex shedding. The vortex shedding frequency and second acoustic frequency dominate the pressure oscillation characteristics in the chamber. Thermal inhibitor position and gas temperature have little effect on vortex shedding frequency, but have great impact on pressure oscillation amplitude. Pressure amplitude is much higher when the thermal inhibitor locates at the acoustic velocity anti-nodes. The farther the thermal inhibitor is to the nozzle head, the more vortex energy would be dissipated by the turbulence. Therefore, the vortex shedding amplitude at the second acoustic velocity antinode near 3/4L （L is chamber length） is larger than those of others. Besides, the natural acoustic frequencies increase with the gas temperature. As the vortex shedding frequency departs from the natural acoustic frequency, the vortex-acoustic feedback loop is decoupled. Consequently, both the vortex shedding and acoustic amplitudes decrease rapidly.展开更多
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
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
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
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
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
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
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
Digital image correlation(DIC)and dislocation based crystal plasticity simulation were utilised to study cold dwell behaviour in a coarse grain Ti-6Al alloy at 3 different temperatures up to 230℃.Strains extracted fr...Digital image correlation(DIC)and dislocation based crystal plasticity simulation were utilised to study cold dwell behaviour in a coarse grain Ti-6Al alloy at 3 different temperatures up to 230℃.Strains extracted from large volume grains were measured during creep by DIC and were used to calibrate the crystal plasticity model.The values of critical resolved shear stresses(CRSS)of the two main slip systems(basal and prismatic)were determined as a function of temperature.Stress along paths across the boundaries of four grain pairs,three“rogue”grain pairs and one“non-rogue”grain pair,were determined at different temperatures.Large load shedding was observed in one of the“rogue”grain pairs,where a stress increment during the creep period was found in the“hard”grain.A minor load shedding mechanism was observed in two non-typical“rogue”grain pairs,in which the plastic deformation is nonuniform inside the grains and geometrically necessary dislocations accumulate in the centre of the grains.At elevated temperatures,120℃was found to be the worst case scenario as the stress difference at the grain boundaries of these four grain pairs was found to be the largest among the three temperatures analysed.The origin of this critical temperature is debated in the literature and it is investigated for the first time in the present work by analysing the simultaneous effects of the geometrically necessary dislocations(GND)and the strain rate sensitivity(SRS)of the slip systems.The analysis shows that the combined effects of the peak SRS of both prismatic and basal slip systems at 80℃and of the increase of the spread of the GND distribution around the grain boundary at higher temperatures are the origin of the observed worst case scenario.展开更多
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
Working memory is one of the essential higher cognitive functions that actively holds behaviorally-relevant information essential for guiding subsequent actions. It includes subsystems that store and manipulate single...Working memory is one of the essential higher cognitive functions that actively holds behaviorally-relevant information essential for guiding subsequent actions. It includes subsystems that store and manipulate singlemode or multi-modal sensory information, e.g., spatial information, visual images, auditory scenes, olfactory objects, or any combination of these. In addition to merely holding a certain amount of information for a short period of time, as is generally believed, the cognitive processes involved are far more complex, including the executive and attentional control of short-term memory, permitting interim integration, and the processing, disposal, and retrieval of information. Evolution-wise, working memory is essential for the behavioral flexibility that allows humans and animals to quickly adapt to rapidly changing environments.展开更多
文摘Jiangsu Niupai Machinery&Elecronics Co,ltd.is National Specialized and New"Little Giant"Enterprise,National High&New Technological Enterprise,Jiangsu Provincial Research Center of Loom Shedding Engineering Technology and Jiangsu Provincial Enterprise Technology Center.The company has obtained SGS-certified ISO9001 quality management system,a globally recognized standard.Niupai specializes in the R&D and manufacturing of cam shedding device,dobby shedding device,jacquard shedding device and heald frames for water-jet looms,air-jet looms as well as rapier looms.
文摘Changshu Textile Machinery Works Co.,Ltd.was founded in 1958 and is a professional R&D and manufacturing enterprise of looms shedding device in China.The company's products cover three series of shedding devices for looms(Dobby,Jacquard,Cam Motion),forming a series of products with electronic shedding devices as the main products,and mechanical shedding devices as the auxiliary products.D2876pro electronic dobby The D2876pro electronic dobby is a high-performance equipment designed for a maximum operating speed of 800rpm.It has 16 cams,and 12mm of pitch,with a high installation type.The shedding type is double lift and full clear open.Its maximum wefts is 12,800 and 100,000.It has a two-stage filtration lubrication with a gerotor pump oil recycle system,and it is suitable for water-jet looms.
基金supported by the National Natural Science Foundation of China(No.11972190)。
文摘A robust Reynolds-Averaged Navier-Stokes(RANS)based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC)rotor.The complex motion with multiple degrees of freedom of the Trailing Edge Flap(TEF)is analyzed by employing an inverse nested overset grid method.Simulation of non-rotational and rotational modes of blade motion are carried out to investigate the formation and development of TEF shedding vortex with high-frequency deflection of TEF.Moreover,the mechanism of TEF deflection interference with blade tip vortex and overall rotor aerodynamics is also explored.In nonrotational mode,two bundles of vortices form at the gap ends of TEF and the main blade and merge into a single TEF vortex.Dynamic deflection of the TEF significantly interferes with the blade tip vortex.The position of the blade tip vortex consistently changes,and its frequency is directly related to the frequency of TEF deflection.In rotational mode,the tip vortex forms a helical structure.The end vortices at the gap sides co-swirl and subsequently merge into the concentrated beam of tip vortices,causing fluctuations in the vorticity and axial position of the tip vortex under the rotor.This research concludes with the investigation on suppression of Blade Vortex Interaction(BVI),showing an increase in miss distance and reduction in the vorticity of tip vortex through TEF phase control at a particular control frequency.Through this mechanism,a designed TEF deflection law increases the miss distance by 34.7%and reduces vorticity by 11.9%at the target position,demonstrating the effectiveness of AFC in mitigating BVI.
基金supported by the National Natural Science Foundation of China(No.52272428)。
文摘The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electrothermal de-icing seldom delve into comprehensive ice accretion-melting-deicing models that account for ice shedding.Therefore,the detachment behavior of ice layers during the heating process requires in-depth research and discussion.This paper physically models the phenomenon of ice shedding,incorporates the detachment behavior of ice layers during heating,improves the existing mathematical model for electro-thermal de-icing calculations,establishes an ice accretion-melting-deicing model for electro-thermal de-icing systems,and conducts numerical simulation,verification and optimization analysis of electro-thermal de-icing considering ice shedding.Through multi-condition de-icing numerical simulations of a specific wing model,it is found that ambient temperature can serve as a factor for adapting the electro heating anti/de-icing strategy to the environment.An optimization of heating heat flux density and heating/cooling time is conducted for the wing de-icing control law under the calculated conditions.The improved electrothermal de-icing model and algorithm developed in this paper provide solid technical support for the design of electrothermal de-icing systems.
基金supported by the China Agriculture Research System (Grant No.CARS-28-14)。
文摘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.
文摘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.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.41972323 and 51991362)Science and Technology Project of the 13th Five-Year Plan of Jilin Provincial Department of Education(Grant No.JJKH20190126KJ)the Science and Technology Developing Plan Project of Jilin Province(Grant No.20200201055JC).
文摘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.
基金supported by the National Natural Sci-ence Foundation of China(No.52077017).
文摘Considering the escalating usage of renewa-ble energy and rising frequency of extreme meteorological events,the risk of emergency load shedding(ELS)in power grids due to faults is increasing.The existing ELS strategies fail to provide users with advance warnings and blackout preparation time.To address this issue,an in-novative strategy called warning and delayed load shed-ding is proposed in this study.In this approach,when it becomes necessary to shed load for emergency control,users are immediately notified with a power outage warning.Subsequently,energy storage and other regula-tory resources are employed to substitute for load shed-ding,thus postponing the execution of the load shedding command.This delay equips users with the ability and time to respond and prepare.To implement this strategy,the operational principles supported by energy storage and backup power are further discussed.Five perfor-mance indexes are utilized to evaluate the delayed load shedding capability.Moreover,the delayed load shedding switch function and energy storage power balance equa-tion are constructed to determine the relationship be-tween energy storage,backup power sources,and load shedding time.Subsequently,two optimized load shed-ding models supported by energy storage are established,i.e.,maximum and flexible delayed models.For compar-ison,improvements are made to the conventional load shedding model without delay by incorporating energy storage.An IEEE 30-node network with energy storage is used to test the three load shedding models.Accordingly,the evaluation indexes are calculated and compared.The results of the performance indexes and comparative analysis validate the effectiveness of the proposed meth-ods,indicating that by using energy storage,users can be notified with advance power outage warnings and prep-aration time.
文摘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.
基金the National Natural Science Foundation of China (Grant No.51076015)
文摘Vortex-acoustic coupling is one of the most important potential sources of combustion instability in solid rocket motors （SRMs）. Based on the Von Karman Institute for Fluid Dynamics （VKI） experimental motor, the influence of the thermal inhibitor position and temperature on vortex-shedding-driven pressure oscillations is numerically studied via the large eddy simulation （LES） method. The simulation results demonstrate that vortex shedding is a periodic process and its accurate frequency can be numerically obtained. Acoustic modes could be easily excited by vortex shedding. The vortex shedding frequency and second acoustic frequency dominate the pressure oscillation characteristics in the chamber. Thermal inhibitor position and gas temperature have little effect on vortex shedding frequency, but have great impact on pressure oscillation amplitude. Pressure amplitude is much higher when the thermal inhibitor locates at the acoustic velocity anti-nodes. The farther the thermal inhibitor is to the nozzle head, the more vortex energy would be dissipated by the turbulence. Therefore, the vortex shedding amplitude at the second acoustic velocity antinode near 3/4L （L is chamber length） is larger than those of others. Besides, the natural acoustic frequencies increase with the gas temperature. As the vortex shedding frequency departs from the natural acoustic frequency, the vortex-acoustic feedback loop is decoupled. Consequently, both the vortex shedding and acoustic amplitudes decrease rapidly.
基金supported by the National Key Scientific Instrument and Equipment Development Program of China (Grant 2011YQ120048)
文摘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.
基金Supported by Startup Fund forYouth Faculty of ShenzhenUniversity, No. 2018009.
文摘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.
基金This project is supported by National Natural Science Foundation of China(No.59835160).
文摘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.
基金Supported by the National Natural Science Foundation of China (30872287)
文摘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.
基金Supported by Grants from the National Institutes of Health,No.AG029859 the National Center of the American Heart Association,No.0330335Nthe New Jersey Commission on Cancer Research(NJCCR703010)to Fan H
文摘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.
基金Supported by National Natural Science Foundation of China(Grant Nos.51209004,11172040)Beijing Municipal Natural Science Foundation of China(Grant No.3144043)
文摘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.
文摘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.
基金the financial support provided by the Henry Royce Institute(No.EP/R010145/1)financial support of the China Scholarship Council(CSC)support through Fellowship grant(No.EP/N007239/1)。
文摘Digital image correlation(DIC)and dislocation based crystal plasticity simulation were utilised to study cold dwell behaviour in a coarse grain Ti-6Al alloy at 3 different temperatures up to 230℃.Strains extracted from large volume grains were measured during creep by DIC and were used to calibrate the crystal plasticity model.The values of critical resolved shear stresses(CRSS)of the two main slip systems(basal and prismatic)were determined as a function of temperature.Stress along paths across the boundaries of four grain pairs,three“rogue”grain pairs and one“non-rogue”grain pair,were determined at different temperatures.Large load shedding was observed in one of the“rogue”grain pairs,where a stress increment during the creep period was found in the“hard”grain.A minor load shedding mechanism was observed in two non-typical“rogue”grain pairs,in which the plastic deformation is nonuniform inside the grains and geometrically necessary dislocations accumulate in the centre of the grains.At elevated temperatures,120℃was found to be the worst case scenario as the stress difference at the grain boundaries of these four grain pairs was found to be the largest among the three temperatures analysed.The origin of this critical temperature is debated in the literature and it is investigated for the first time in the present work by analysing the simultaneous effects of the geometrically necessary dislocations(GND)and the strain rate sensitivity(SRS)of the slip systems.The analysis shows that the combined effects of the peak SRS of both prismatic and basal slip systems at 80℃and of the increase of the spread of the GND distribution around the grain boundary at higher temperatures are the origin of the observed worst case scenario.
基金This study was conducted according to the declaration of Helsinki and approved by the Ethics Committee(Unique Regional Ethical Committee,Friuli Venezia-Giulia 16 April 2020),No.CEUR 2020-OS-072.
文摘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.
文摘Working memory is one of the essential higher cognitive functions that actively holds behaviorally-relevant information essential for guiding subsequent actions. It includes subsystems that store and manipulate singlemode or multi-modal sensory information, e.g., spatial information, visual images, auditory scenes, olfactory objects, or any combination of these. In addition to merely holding a certain amount of information for a short period of time, as is generally believed, the cognitive processes involved are far more complex, including the executive and attentional control of short-term memory, permitting interim integration, and the processing, disposal, and retrieval of information. Evolution-wise, working memory is essential for the behavioral flexibility that allows humans and animals to quickly adapt to rapidly changing environments.
