The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameteri...The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameterization within the overall cumulus parameterization scheme.In this study,an improved bulk-plume method is proposed by solving the equations of two conserved variables simultaneously to calculateλof cumulus clouds in a large-eddy simulation.The results demonstrate that the improved bulk-plume method is more reliable than the traditional bulk-plume method,becauseλ,as calculated from the improved method,falls within the range ofλvalues obtained from the traditional method using different conserved variables.The probability density functions ofλfor all data,different times,and different heights can be well-fitted by a log-normal distribution,which supports the assumed stochastic entrainment process in previous studies.Further analysis demonstrate that the relationship betweenλand the vertical velocity is better than other thermodynamic/dynamical properties;thus,the vertical velocity is recommended as the primary influencing factor for the parameterization ofλin the future.The results of this study enhance the theoretical understanding ofλand its influencing factors and shed new light on the development ofλparameterization.展开更多
Background:Transzonal projections(TZPs)constitute a structural basis for the communication between the oocyte and its surrounding cumulus cells(CCs),which play critical roles in promoting the oocyte maturation.Previou...Background:Transzonal projections(TZPs)constitute a structural basis for the communication between the oocyte and its surrounding cumulus cells(CCs),which play critical roles in promoting the oocyte maturation.Previously we found that heat stress(HS)causes loss of TZPs in porcine cumulus-oocyte complexes(COCs)with decreased density of filamentous actin(F-actin).However,the time-course responses of F-actin and its monomeric actins(β-actin andγ-actin)during the in vitro maturation of oocytes remain unclear.Results:In this study,excised porcine ovaries were exposed to HS at 41.5°C for 1 h before COCs were isolated and matured in vitro for 44 h.HS significantly reduced oocyte quality,characterized by impaired cumulus expansion,delayed meiotic resumption and lower survival rate and polar body extrusion rate,as well as decreased expression of mitochondrial DNA-encoded genes and elevated mitochondrial reactive oxygen species concentration.Expression ofβ-actin andγ-actin in CCs increased gradually with oocytes maturation,which was significantly reduced in HS group,especially at 24 h and/or 44 h of in vitro maturation.By contrast,the number of TZPs and the fluorescence intensity of F-actin in zona pellucida decreased gradually during oocytes maturation,which were significantly reduced by HS at 24 h of in vitro maturation.Moreover,colocalization analyses revealed bothβ-actin andγ-actin contribute to the F-actin formation in porcine TZPs,and the colocalization of F-actin with GJ protein connexin 45 was significantly reduced in heat-exposed COCs.Conclusions:The results indicate that the suppression of actin expressions in CCs,which may lead to the F-actin unstabilization in TZPs,will subsequently contribute to the compromised quality of oocytes under HS.展开更多
Objective:To understand the level of progesterone (P4) in different quality of buffalo cumulus oocyte complexes (COCs) and further to evaluate the effect of exogenous P4 supplementation on maturation and subsequent de...Objective:To understand the level of progesterone (P4) in different quality of buffalo cumulus oocyte complexes (COCs) and further to evaluate the effect of exogenous P4 supplementation on maturation and subsequent developmental ability of poor quality brilliant cresyl blue (BCB-)COCs.Methods: Progesterone secreted by different quality of buffalo oocytes was estimated by enzyme linked immunosorbent assay and the concentration differences were translated into P4 doses to be incorporated in the maturation medium of BCB-ve COCs followed by expression analysis of genes involved in the cumulus expansion, extracellular matrix disintegration and progesterone receptor signalling. In addition, the study also evaluated the effect of exogenous P4 on sperm-cumulus interaction. Results: More than 10-fold up-regulated expression of progesterone receptor in P4 supplemented oocytes signified that P4 might be acting predominantly through this receptor. Also, exogenous P4 supplementation had significant effect on transcatheter arterial chemoembolization protease regulated by P4-progesterone receptor pathway which in turn had an important role in extracellular matrix disintegration. On the contrary, cumulus expansion genesHAS2,TNFAIP6,AREG were not altered upon P4 supplementation. Also, it was observed that P4 addition did facilitate passage of significantly more number of spermatozoa through P4 treated cumulus cells. Further, incorporation of different doses of P4 did not improve significantly the cleavage and blastocyst rates of BCB-ve COCs.Conclusions: Different qualities of buffalo COCs secrete substantially diverse levels of P4, and its supplementation has a role in oocyte maturation via modulation of cumulus characteristics but perhaps not fertilization.展开更多
The short-term insemination technique has been widely applied, although it is not clear whether the mechanical desorption of cumulus cells can affect normal fertilization and birth outcomes. Therefore, the present stu...The short-term insemination technique has been widely applied, although it is not clear whether the mechanical desorption of cumulus cells can affect normal fertilization and birth outcomes. Therefore, the present study aimed to evaluate whether early cumulus cell removal could affect in vitro fertilization outcomes. Based on a history of infertility and semen analysis, 61 patients were identified, and the cumulus cells were mechanically removed at either6 h post-insemination (Group A, 387 mature oocytes) or 18 - 20 h post-insemination as traditional in vitro fertilization (Group B, 424 mature oocytes). There were no significant differences in the rates of fertilization, available embryos, high quality embryos, birth, premature birth, pregnancy, or implantation when we compared the two groups. However, Group A exhibited a significantly higher polyspermy rate, and significantly lower rates of blastocyst formation and high-quality blastocyst formation, compared with Group B. Therefore, the results of present study indicate that early cumulus cell removal (at 6 h post-insemination) may negatively affect the rates of polyspermy, blastocyst formation, and high-quality blastocyst formation.展开更多
According to the characteristics of organized cumulus convective precipitation in China,a cumulus parameterization scheme suitable for describing the organized convective precipitation in East Asia is presented and mo...According to the characteristics of organized cumulus convective precipitation in China,a cumulus parameterization scheme suitable for describing the organized convective precipitation in East Asia is presented and modified.The Kain-Fristch scheme is chosen as the scheme to be modified based on analyses and comparisons of simulated precipitation in East Asia by several commonly-used mesoscale parameterization schemes.A key dynamic parameter to dynamically control the cumulus parameterization is then proposed to improve the Kain-Fristch scheme.Numerical simulations of a typhoon case and a Mei-yu front rainfall case are carried out with the improved scheme,and the results show that the improved version performs better than the original in simulating the track and intensity of the typhoons,as well as the distribution of Mei-yu front precipitation.展开更多
The present work was designed to examine the effect of the presence or absence of cumulus cells on the efficiency of vitrification of immature cattle oocytes. In our experiment, we had two groups: group 1, immature ca...The present work was designed to examine the effect of the presence or absence of cumulus cells on the efficiency of vitrification of immature cattle oocytes. In our experiment, we had two groups: group 1, immature cattle oocytes with cumulus cells and group 2, immature cattle oocytes without cumulus cells. The two groups underwent vitrification using 20% ethylene glycol and 20% DMSO, and then thawed, and in vitro matured in TCM-199 medium and examined after 22 hours for assessment of nuclear maturation. Higher survival rate (p < 0.05) after thawing was observed in group 1 (84.6%) than group 2 (57.8%). After in-vitro maturation, the rate of MII oocytes was significantly higher (p < 0.05) in group 1 (74.4%) than group 2 (47.7%). In conclusion, the cumulus cells are very important in increasing the survivability and developmental rate of vitrified-thawed immature cattle oocytes.展开更多
The study explored the ability of four cumulus parameterization schemes (CPSs) from Weather and Research Forecasting model (WRF) to simulate mean rainfall patterns, number of rainy days (NRD) and vertically integrated...The study explored the ability of four cumulus parameterization schemes (CPSs) from Weather and Research Forecasting model (WRF) to simulate mean rainfall patterns, number of rainy days (NRD) and vertically integrated moisture flux (VIMF) during the composite of wet years for the core rainfall seasons of March-April-May (MAM;1989, 1998 and 2012) and Octo-ber-November-December (OND;1997, 2006 and 2015) seasons. The CPSs used were Kain-Fritsch (KF), Kain-Fritsch with a moisture-advection based trigger function (KFT), Grell Dévényi (GRELL) and Betts Miller Janjic (BML). The simulations by the GRELL and KF schemes were clearly separated by the dry and wet rainfall gradient in the simulations. For example, the GRELL scheme rainfall simulations were drier over the eastern parts of the region bet-ter. The KF and KFT schemes generated wetter rainfall conditions mainly con-fined to the western parts of the region. The BML scheme simulations were not consistent with the observations. The western and eastern parts of the region were characterized by more and fewer NRD, in both the KF and GRELL schemes. The root mean square error (RMSE) and spatial correlation by KF scheme was 2 mm/day and 0.6. The GRELL scheme however simulated low correlation of 0.45 and RMSE of about 3.0 mm/day over most of the sub-domains. The moisture convergence biases were found to be larger conti-nentally and parts of the nearby Indian Ocean. The persisting rainfall biases constituting of too wet and dry conditions were associated with the KF and GRELL cumulus schemes. The findings from the current study are very funda-mental for the improvement of numerical weather prediction (NWP) tools and cumulus modification processes over the region. The accurate and higher skill rainfall forecasts would provide early warning information for disaster risk re-duction and the related risks on the livelihoods.展开更多
Based on the existing cumulus convective parameterization schemes,a mass flux scheme(MFS)for cumulus convective parameterization has been successfully developed by reference to thework of Chen et al.(1996).The MFS is ...Based on the existing cumulus convective parameterization schemes,a mass flux scheme(MFS)for cumulus convective parameterization has been successfully developed by reference to thework of Chen et al.(1996).The MFS is a comprehensive scheme.In MFS,not only theimportance of the large-scale moisture convergence is taken into account,but also it includes thecumulus updrafts and downdrafts,cumulus-induced subsidence in the environmental air.entrainment,detrainment and evaporation.The interaction between the cumulus and theenvironment is described by using a one-dimensional bulk model.At the same time the schemeincludes the penetrative and shallow convections.The MFS has been successfully incorporated into the regional climate model RegCM2developed by NCAR.The new model has been applied to simulate summer monsoon characteristicsand their variations of heavy rainfall process in the Changjiang-Huaihe River Basins for threemonths from May to July 1991.The results show that the new model can successfully simulate thisrainfall prolonged process.By comparising the model outputs of RegCM2.using the Kuo schemeand the MFS.it is found that the MFS is better in simulating the surface temperature,rainfallposition and amount,and rainfall duration.展开更多
By comparison of simulated cumulus convection processes in RegCM2,using the Kuo scheme,the Grell scheme and the mass flux scheme (MFS),it is found that the MFS can simulate thecumulus heating and moistening very well....By comparison of simulated cumulus convection processes in RegCM2,using the Kuo scheme,the Grell scheme and the mass flux scheme (MFS),it is found that the MFS can simulate thecumulus heating and moistening very well.A series of sensitivity tests show that the parametersfor specifying the conversion coefficient from cloud droplets to raindrops,the turbulententrainment and detrainment rates in updrafts anddowndrafts,and the intensity of thedowndraftshave different degrees of influence upon the cumulus convection.Therefore.it is quite importantfor cumulus parameterization scheme to define these parameters as accurately as possible.展开更多
Short-term cultured cumulus cell lines (1-5BCC) derived from 5 individual cows were used in nuclear transfer (NT) and 1188 enucleated bovine oocytes matured in vitro were used as nuclear recipients. A total of 931 (78...Short-term cultured cumulus cell lines (1-5BCC) derived from 5 individual cows were used in nuclear transfer (NT) and 1188 enucleated bovine oocytes matured in vitro were used as nuclear recipients. A total of 931 (78.4%) cloned embryos were reconstructed, of which 763 (82%) cleaved, 627 (67.3%) developed to 8-cell stage, and 275 (29.5%) reached blastocyst stage. The average cell number of blastocysts was 124±24.5 (n=20). In this study, the effects of donor cell sources, serum starvation of donor cells, time interval from fusion to activation (IFA) were also tested on cloning efficiency. These results showed that blastocyst rates of embryos reconstructed from 5 different individuals cells were significantly different among them (14.1%, 45.2%, 27.3%, 34.3%, vs 1.5%, P<0.05); that serum starvation of donor cells had no effect on blastocyst development rate of NT embryos (47.1% vs 44.4%, P>0.05); and that blastocyst rate (20.3%) of the group with fusion/activation interval of 2-3 h, was significantly lower than that of the 3-6 h groups (31.0%), while not significantly different among 3-4 h (P < 0.05), 4-5 h, and 5-6 h groups (P ≥ 0.05). Sixty-three thawed NT blastocysts were transferred to 31 recipient cows, of which 4 pregnancies were established and two cloned calves were given birth. These results indicate that serum starvation of cumulus cells is not a key factor for successful bovine cloning, while IFA treatment and sources of donor cells have effects on cloning efficiency.展开更多
Ozone chemistry processes are analyzed during a cumulus cloud process with the model（1CCCM）described in Part Ⅰ.The simulation results show that entire cumulus cloud process can bewell described with the development...Ozone chemistry processes are analyzed during a cumulus cloud process with the model（1CCCM）described in Part Ⅰ.The simulation results show that entire cumulus cloud process can bewell described with the development of vertical velocities and liquid water content which are the twomost outstanding features of cumulus clouds.Ozone chemistry is strongly influenced by cumulusclouds.NO<sub>x</sub> can be transported upwards above 4 km in the first 20 minutes of the convection eventand form a relative higher concentration area which enhances the production of ozone.Two areas ap-pear during the convection event:area of net ozone production and area of net ozone depletion.Thearea of ozone depletion coincides with the area of liquid water within cloud.Results show that theaqueous phase（cloud water and rainwater）can alter gas ozone level through two ways:one is scav-enging free radicals（HO<sub>2</sub>）from the gas phase and thereby inhibiting the reactions of transformationto NO<sub>2</sub> from NO,which results in reduction of the gas source of ozone;the other is aqueous phasechemical reactions which consume ozone in the aqueous phase.Calculations reveal that the reaction O<sub>3</sub>+OH→HO<sub>2</sub> is the main pathway of ozone depletion in gas phase during the process of cumulusclouds.展开更多
An operational weather forecast model,coupled to an oceanic model,was used to predict the initiation and propagation of two major Madden–Julian Oscillation(MJO)events during the dynamics of the MJO(DYNAMO)campaign pe...An operational weather forecast model,coupled to an oceanic model,was used to predict the initiation and propagation of two major Madden–Julian Oscillation(MJO)events during the dynamics of the MJO(DYNAMO)campaign period.Two convective parameterization schemes were used to understand the sensitivity of the forecast to the model cumulus scheme.The first is the Tiedtke(TDK)scheme,and the second is the Simplified Arakawa–Schubert(SAS)scheme.The TDK scheme was able to forecast the MJO-1 and MJO-2 initiation at 15-and45-day lead,respectively,while the SAS scheme failed to predict the convection onset in the western equatorial Indian Ocean(WEIO).The diagnosis of the forecast results indicates that the successful prediction with the TDK scheme is attributed to the model capability to reproduce the observed intraseasonal outgoing longwave radiation–sea surface temperature(OLR–SST)relationship.On one hand,the SST anomaly(SSTA)over the WEIO was induced by surface heat flux anomalies associated with the preceding suppressed-phase MJO.The change of SSTA,in turn,caused boundary layer convergence and ascending motion,which further induced a positive column-integrated moist static energy(MSE)tendency,setting up a convectively unstable stratification for MJO initiation.The forecast with the SAS scheme failed to reproduce the observed OLR–SST–MSE relation.The propagation characteristics differed markedly between the two forecasts.Pronounced eastward phase propagation in the TDK scheme is attributed to a positive zonal gradient of the MSE tendency relative to the MJO center,similar to the observed,whereas a reversed gradient appeared in the forecast with the SAS scheme with dominant westward propagation.The difference is primarily attributed to anomalous vertical and horizontal MSE advection.展开更多
It was shown that expansion of porcine cumulus did not depend on oocyte-secreted factor(s), and it is therefore presumed that porcine CEEF may not be produced exclusively by the oocyte. In this experiment, we used mou...It was shown that expansion of porcine cumulus did not depend on oocyte-secreted factor(s), and it is therefore presumed that porcine CEEF may not be produced exclusively by the oocyte. In this experiment, we used mouse oocytectomized complexes (OOX), which were incapable of CEEF production, to assess the secretion of CEEF by evacuated zona, oocytes of different quality and somatic cells in the porcine follicles. The results showed that: (i) Evacuated zonae from both porcine and mouse oocytes did not produce CEEF. (ii) Porcine oocytes of A, B and C types from 3-6 mm follicles were not significantly different in both production and activity of CEEF. (iii) Both porcine OOX from 3-6 mm follicles and granulose cells from 【 1 mm follicles secreted CEEF in a large quantity, independent of gonadotro-pins; mural granulose cells from 3-6 mm follicles, however, produced neglectable amount of CEEF. (iv) The follicular fluid from 3-6 mm porcine follicles contained CEEF activity that was concentration-dependent,展开更多
According to the characteristics of cumulus and stratiform clouds during the meiyu period (plum rains) over Jianghuai valleys (the Changjiang (Yangtze) River and the Huaihe River), a modified Kuo-type cumulus paramete...According to the characteristics of cumulus and stratiform clouds during the meiyu period (plum rains) over Jianghuai valleys (the Changjiang (Yangtze) River and the Huaihe River), a modified Kuo-type cumulus parameterization scheme applicable to midlatitude con-vective systems is suggested in this paper. It is often observed that cumulus and stratiform clouds coexist in a rain-bearing synoptic systems and the precipitation amount associated with this system may be amplified by their interaction. With some important processes of cloud physics taken into account, we use a simple seeder-feeder model (including colloidal instability, collision effect and entrainment) to describe this process of interaction within framework of Kuo-type cumulus parameterization. It is found that the rainfall amount caused by ice crystal effect accounts for 30-40% of total rainfall, but the collision effect is not so great generally. We introduced this scheme to the regional numerical model used by Wuhan Observatory of展开更多
In this paper, a 1-D time dependent cold cumulus chemistry model is presented. In the coldcumulus model, 4 categories of hydrometeors: cloud drops, raindrops, cloud ice crystals, graupelparticles, and 18 microphysical...In this paper, a 1-D time dependent cold cumulus chemistry model is presented. In the coldcumulus model, 4 categories of hydrometeors: cloud drops, raindrops, cloud ice crystals, graupelparticles, and 18 microphysical interactions are considered, In the chemical model, the source andsink terms for pollutants include: the complicated interactions between pollutants (gases andaerosol particles) and the hydrometeors (especially ice crystals and graupel particles), the ex-changes of chemical compounds between two hydrometeors accompanying microphysical processesand the aqueous oxidations of S (IV) to S (VI). The two models are combined to study the acidifi-cation processes in cold cumulus clouds.展开更多
Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the zygote.One of the steps,acrosome reaction(AR),is an exocytosis process,during which the outer a...Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the zygote.One of the steps,acrosome reaction(AR),is an exocytosis process,during which the outer acrosome membrane fuses with the inner sperm membrane,leading to the release of acrosome enzymes that facilitate sperm penetration of the egg investments.Though AR has been investigated for decades,the initial steps of AR in vivo,however,remain largely unknown.A well elucidated model holds the view that AR occurs on the surface of the zona pellucida(ZP),which is triggered by binding of sperm with one of the ZP glycosylated protein,ZP3.However,this model fails to explain the large number of‘falsely’acrosome-reacted sperms found within the cumulus layer in many species examined.With the emerging evidence of cross-talk between sperm and cumulus cells,the potential significance of AR in the cumulus oophorus,the outer layer of the egg,has been gradually revealed.Here we review the acrosome status within the cumulus layer,the cross-talk between sperm and cumulus cells with the involvement of a novel spermreleased factor,NYD-SP8,and re-evaluate the importance and physiological significance of the AR in the cumulus in fertilization.展开更多
Objective:The transcriptional profile of cumulus cells(CCs)during oocyte maturation provides information for predicting oocyte developmental competence.Our previous study using a mouse model indicated that there were ...Objective:The transcriptional profile of cumulus cells(CCs)during oocyte maturation provides information for predicting oocyte developmental competence.Our previous study using a mouse model indicated that there were nine different genes related to oocyte development potential expressed in CCs during oocyte maturation.The purpose of this study was to elucidate whether gene expression levels of CCs during oocyte maturation are associated with oocyte developmental competence.Methods:The human CCs collected from each oocyte were divided into two groups after tracking depending on whether or not they developed to the blastocyst stage:(1)the oocytes were developed to blastocyst stage after fertilization(B+)and(2)the oocytes were not developed to blastocyst stage after fertilization(B−).The expression levels of the nine selected genes(ARRB1,ATP2C1,CDH5,CNTNAP1,LGR4,MKLN1,RHOBTB1,SIX2,and SMC2)were examined.CCs were obtained from 29 women who were undergoing intracytoplasmic sperm injection treatment cycles.Quantitative reverse transcriptase-polymerase chain reaction analysis was performed on cumulus masses collected before insemination.Each sample was run three times.Statistically significant differences in mRNA expression of the target genes in independent samples were evaluated by two-tailed Student’s t-test,and P<0.05 was considered significantly different.Results:There were significant differences in the mRNA expression levels of ARRB1(P=0.016),LGR4(P=0.025),and SMC2(P=0.013)between the groups B+and B−.Gene expression of ARRB1,LGR4,and SMC2 in CCs is related to blastocyst development.Conclusions:Analysis of expression of ARRB1,LGR4,and SMC2 genes in CCs as biomarkers may provide predictive information on oocyte developmental competence before insemination and fertilization.展开更多
Currently-placed protocols for extended culture for in vitro fertilization(IVF)and intracytoplasmic sperm injection(ICSI)are not uniformly standardized in determining the optimal stage of oocyte maturation for maximiz...Currently-placed protocols for extended culture for in vitro fertilization(IVF)and intracytoplasmic sperm injection(ICSI)are not uniformly standardized in determining the optimal stage of oocyte maturation for maximizing clinical outcomes.The objective of this systematic review is to elucidate the relationship between extended cumulus-oocyte culture and its effect on the clinical outcomes of IVF/ICSI.We included an electronic search on PubMed Central as well as the Journal of Fertility and Sterility to yield seven studies on extended oocyte culture for IVF/ICSI.Four of the seven investigations illustrate the promising beneficial relationship of extended culture with conditioned or supplemented media to mimic physiological uterine conditions.Three studies did not capture beneficial relationships between extended oocyte culture and clinical outcomes with unconditioned,unsupplemented maturation medium.Improvement in fertilization rates,oocyte development,and live birth rates may be achieved by extended culture with the addition of supplemental biochemicals.The usage of follicular fluid,cumulus cells,and meiotic inhibitors imitates the physiological in vivo conditions,whereas extended oocyte culture imitates in vivo temporal conditions.The conjunction of extended oocyte culture with supplemented metabolites,either added in maturation media manually or secreted by cumulus-oocyte complexes,mimics natural uterine physiological conditions to improve clinical outcomes for patients seeking IVF/ICSI.展开更多
The recent progress in the association of cumulus cells with immune functions is a largely ignored area.With over 350 million new sexually transmitted infections occurring annually in adults of reproductive age,we fee...The recent progress in the association of cumulus cells with immune functions is a largely ignored area.With over 350 million new sexually transmitted infections occurring annually in adults of reproductive age,we feel the need to explore more about how the cumulus cells defend themselves and protect the oocytes during the development through the ovulation period.Application of assisted reproductive technologies allows scientists to study and better understand cumulus cells.There are still many immune factors to be taken into consideration to optimize the oocyte quality besides ovarian stimulations.The objective of this review is to summarize the key elements of cumulus cells and their association with the immune function.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42175099,42027804,42075073)the Innovative Project of Postgraduates in Jiangsu Province in 2023(Grant No.KYCX23_1319)+3 种基金supported by the National Natural Science Foundation of China(Grant No.42205080)the Natural Science Foundation of Sichuan(Grant No.2023YFS0442)the Research Fund of Civil Aviation Flight University of China(Grant No.J2022-037)supported by the National Key Scientific and Technological Infrastructure project“Earth System Science Numerical Simulator Facility”(Earth Lab)。
文摘The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameterization within the overall cumulus parameterization scheme.In this study,an improved bulk-plume method is proposed by solving the equations of two conserved variables simultaneously to calculateλof cumulus clouds in a large-eddy simulation.The results demonstrate that the improved bulk-plume method is more reliable than the traditional bulk-plume method,becauseλ,as calculated from the improved method,falls within the range ofλvalues obtained from the traditional method using different conserved variables.The probability density functions ofλfor all data,different times,and different heights can be well-fitted by a log-normal distribution,which supports the assumed stochastic entrainment process in previous studies.Further analysis demonstrate that the relationship betweenλand the vertical velocity is better than other thermodynamic/dynamical properties;thus,the vertical velocity is recommended as the primary influencing factor for the parameterization ofλin the future.The results of this study enhance the theoretical understanding ofλand its influencing factors and shed new light on the development ofλparameterization.
基金This work was supported by the National Key Research and Development Program of China(Grant number 2016YFD0500502)the National Basic Research Program of China(Grant number 2014CB138502)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsand the Jiangsu Collaborative Innovation Center of Meat Production and Processing,Quality and Safety Control.
文摘Background:Transzonal projections(TZPs)constitute a structural basis for the communication between the oocyte and its surrounding cumulus cells(CCs),which play critical roles in promoting the oocyte maturation.Previously we found that heat stress(HS)causes loss of TZPs in porcine cumulus-oocyte complexes(COCs)with decreased density of filamentous actin(F-actin).However,the time-course responses of F-actin and its monomeric actins(β-actin andγ-actin)during the in vitro maturation of oocytes remain unclear.Results:In this study,excised porcine ovaries were exposed to HS at 41.5°C for 1 h before COCs were isolated and matured in vitro for 44 h.HS significantly reduced oocyte quality,characterized by impaired cumulus expansion,delayed meiotic resumption and lower survival rate and polar body extrusion rate,as well as decreased expression of mitochondrial DNA-encoded genes and elevated mitochondrial reactive oxygen species concentration.Expression ofβ-actin andγ-actin in CCs increased gradually with oocytes maturation,which was significantly reduced in HS group,especially at 24 h and/or 44 h of in vitro maturation.By contrast,the number of TZPs and the fluorescence intensity of F-actin in zona pellucida decreased gradually during oocytes maturation,which were significantly reduced by HS at 24 h of in vitro maturation.Moreover,colocalization analyses revealed bothβ-actin andγ-actin contribute to the F-actin formation in porcine TZPs,and the colocalization of F-actin with GJ protein connexin 45 was significantly reduced in heat-exposed COCs.Conclusions:The results indicate that the suppression of actin expressions in CCs,which may lead to the F-actin unstabilization in TZPs,will subsequently contribute to the compromised quality of oocytes under HS.
文摘Objective:To understand the level of progesterone (P4) in different quality of buffalo cumulus oocyte complexes (COCs) and further to evaluate the effect of exogenous P4 supplementation on maturation and subsequent developmental ability of poor quality brilliant cresyl blue (BCB-)COCs.Methods: Progesterone secreted by different quality of buffalo oocytes was estimated by enzyme linked immunosorbent assay and the concentration differences were translated into P4 doses to be incorporated in the maturation medium of BCB-ve COCs followed by expression analysis of genes involved in the cumulus expansion, extracellular matrix disintegration and progesterone receptor signalling. In addition, the study also evaluated the effect of exogenous P4 on sperm-cumulus interaction. Results: More than 10-fold up-regulated expression of progesterone receptor in P4 supplemented oocytes signified that P4 might be acting predominantly through this receptor. Also, exogenous P4 supplementation had significant effect on transcatheter arterial chemoembolization protease regulated by P4-progesterone receptor pathway which in turn had an important role in extracellular matrix disintegration. On the contrary, cumulus expansion genesHAS2,TNFAIP6,AREG were not altered upon P4 supplementation. Also, it was observed that P4 addition did facilitate passage of significantly more number of spermatozoa through P4 treated cumulus cells. Further, incorporation of different doses of P4 did not improve significantly the cleavage and blastocyst rates of BCB-ve COCs.Conclusions: Different qualities of buffalo COCs secrete substantially diverse levels of P4, and its supplementation has a role in oocyte maturation via modulation of cumulus characteristics but perhaps not fertilization.
文摘The short-term insemination technique has been widely applied, although it is not clear whether the mechanical desorption of cumulus cells can affect normal fertilization and birth outcomes. Therefore, the present study aimed to evaluate whether early cumulus cell removal could affect in vitro fertilization outcomes. Based on a history of infertility and semen analysis, 61 patients were identified, and the cumulus cells were mechanically removed at either6 h post-insemination (Group A, 387 mature oocytes) or 18 - 20 h post-insemination as traditional in vitro fertilization (Group B, 424 mature oocytes). There were no significant differences in the rates of fertilization, available embryos, high quality embryos, birth, premature birth, pregnancy, or implantation when we compared the two groups. However, Group A exhibited a significantly higher polyspermy rate, and significantly lower rates of blastocyst formation and high-quality blastocyst formation, compared with Group B. Therefore, the results of present study indicate that early cumulus cell removal (at 6 h post-insemination) may negatively affect the rates of polyspermy, blastocyst formation, and high-quality blastocyst formation.
基金National Basic Research Program of China(2013CB430105)National Natural Science Foundation of China(41405059,40775038,40875031,40975036)
文摘According to the characteristics of organized cumulus convective precipitation in China,a cumulus parameterization scheme suitable for describing the organized convective precipitation in East Asia is presented and modified.The Kain-Fristch scheme is chosen as the scheme to be modified based on analyses and comparisons of simulated precipitation in East Asia by several commonly-used mesoscale parameterization schemes.A key dynamic parameter to dynamically control the cumulus parameterization is then proposed to improve the Kain-Fristch scheme.Numerical simulations of a typhoon case and a Mei-yu front rainfall case are carried out with the improved scheme,and the results show that the improved version performs better than the original in simulating the track and intensity of the typhoons,as well as the distribution of Mei-yu front precipitation.
文摘The present work was designed to examine the effect of the presence or absence of cumulus cells on the efficiency of vitrification of immature cattle oocytes. In our experiment, we had two groups: group 1, immature cattle oocytes with cumulus cells and group 2, immature cattle oocytes without cumulus cells. The two groups underwent vitrification using 20% ethylene glycol and 20% DMSO, and then thawed, and in vitro matured in TCM-199 medium and examined after 22 hours for assessment of nuclear maturation. Higher survival rate (p < 0.05) after thawing was observed in group 1 (84.6%) than group 2 (57.8%). After in-vitro maturation, the rate of MII oocytes was significantly higher (p < 0.05) in group 1 (74.4%) than group 2 (47.7%). In conclusion, the cumulus cells are very important in increasing the survivability and developmental rate of vitrified-thawed immature cattle oocytes.
文摘The study explored the ability of four cumulus parameterization schemes (CPSs) from Weather and Research Forecasting model (WRF) to simulate mean rainfall patterns, number of rainy days (NRD) and vertically integrated moisture flux (VIMF) during the composite of wet years for the core rainfall seasons of March-April-May (MAM;1989, 1998 and 2012) and Octo-ber-November-December (OND;1997, 2006 and 2015) seasons. The CPSs used were Kain-Fritsch (KF), Kain-Fritsch with a moisture-advection based trigger function (KFT), Grell Dévényi (GRELL) and Betts Miller Janjic (BML). The simulations by the GRELL and KF schemes were clearly separated by the dry and wet rainfall gradient in the simulations. For example, the GRELL scheme rainfall simulations were drier over the eastern parts of the region bet-ter. The KF and KFT schemes generated wetter rainfall conditions mainly con-fined to the western parts of the region. The BML scheme simulations were not consistent with the observations. The western and eastern parts of the region were characterized by more and fewer NRD, in both the KF and GRELL schemes. The root mean square error (RMSE) and spatial correlation by KF scheme was 2 mm/day and 0.6. The GRELL scheme however simulated low correlation of 0.45 and RMSE of about 3.0 mm/day over most of the sub-domains. The moisture convergence biases were found to be larger conti-nentally and parts of the nearby Indian Ocean. The persisting rainfall biases constituting of too wet and dry conditions were associated with the KF and GRELL cumulus schemes. The findings from the current study are very funda-mental for the improvement of numerical weather prediction (NWP) tools and cumulus modification processes over the region. The accurate and higher skill rainfall forecasts would provide early warning information for disaster risk re-duction and the related risks on the livelihoods.
基金Supported by"National Key Program for Developing Basic Sciences"G1998040900the National Natural Science Foundation of China(No.49794030).
文摘Based on the existing cumulus convective parameterization schemes,a mass flux scheme(MFS)for cumulus convective parameterization has been successfully developed by reference to thework of Chen et al.(1996).The MFS is a comprehensive scheme.In MFS,not only theimportance of the large-scale moisture convergence is taken into account,but also it includes thecumulus updrafts and downdrafts,cumulus-induced subsidence in the environmental air.entrainment,detrainment and evaporation.The interaction between the cumulus and theenvironment is described by using a one-dimensional bulk model.At the same time the schemeincludes the penetrative and shallow convections.The MFS has been successfully incorporated into the regional climate model RegCM2developed by NCAR.The new model has been applied to simulate summer monsoon characteristicsand their variations of heavy rainfall process in the Changjiang-Huaihe River Basins for threemonths from May to July 1991.The results show that the new model can successfully simulate thisrainfall prolonged process.By comparising the model outputs of RegCM2.using the Kuo schemeand the MFS.it is found that the MFS is better in simulating the surface temperature,rainfallposition and amount,and rainfall duration.
基金Supported by"National Key Program for Developing Basic Sciences"G1998040900the National Natural Science Foundation of China(No.49794030).
文摘By comparison of simulated cumulus convection processes in RegCM2,using the Kuo scheme,the Grell scheme and the mass flux scheme (MFS),it is found that the MFS can simulate thecumulus heating and moistening very well.A series of sensitivity tests show that the parametersfor specifying the conversion coefficient from cloud droplets to raindrops,the turbulententrainment and detrainment rates in updrafts anddowndrafts,and the intensity of thedowndraftshave different degrees of influence upon the cumulus convection.Therefore.it is quite importantfor cumulus parameterization scheme to define these parameters as accurately as possible.
基金This work was supported by the National "863" Project in China and Beijing Municipal Natural Sciences Foundation.
文摘Short-term cultured cumulus cell lines (1-5BCC) derived from 5 individual cows were used in nuclear transfer (NT) and 1188 enucleated bovine oocytes matured in vitro were used as nuclear recipients. A total of 931 (78.4%) cloned embryos were reconstructed, of which 763 (82%) cleaved, 627 (67.3%) developed to 8-cell stage, and 275 (29.5%) reached blastocyst stage. The average cell number of blastocysts was 124±24.5 (n=20). In this study, the effects of donor cell sources, serum starvation of donor cells, time interval from fusion to activation (IFA) were also tested on cloning efficiency. These results showed that blastocyst rates of embryos reconstructed from 5 different individuals cells were significantly different among them (14.1%, 45.2%, 27.3%, 34.3%, vs 1.5%, P<0.05); that serum starvation of donor cells had no effect on blastocyst development rate of NT embryos (47.1% vs 44.4%, P>0.05); and that blastocyst rate (20.3%) of the group with fusion/activation interval of 2-3 h, was significantly lower than that of the 3-6 h groups (31.0%), while not significantly different among 3-4 h (P < 0.05), 4-5 h, and 5-6 h groups (P ≥ 0.05). Sixty-three thawed NT blastocysts were transferred to 31 recipient cows, of which 4 pregnancies were established and two cloned calves were given birth. These results indicate that serum starvation of cumulus cells is not a key factor for successful bovine cloning, while IFA treatment and sources of donor cells have effects on cloning efficiency.
基金This work was supported by the National Natural Science Foundation of China.
文摘Ozone chemistry processes are analyzed during a cumulus cloud process with the model（1CCCM）described in Part Ⅰ.The simulation results show that entire cumulus cloud process can bewell described with the development of vertical velocities and liquid water content which are the twomost outstanding features of cumulus clouds.Ozone chemistry is strongly influenced by cumulusclouds.NO<sub>x</sub> can be transported upwards above 4 km in the first 20 minutes of the convection eventand form a relative higher concentration area which enhances the production of ozone.Two areas ap-pear during the convection event:area of net ozone production and area of net ozone depletion.Thearea of ozone depletion coincides with the area of liquid water within cloud.Results show that theaqueous phase（cloud water and rainwater）can alter gas ozone level through two ways:one is scav-enging free radicals（HO<sub>2</sub>）from the gas phase and thereby inhibiting the reactions of transformationto NO<sub>2</sub> from NO,which results in reduction of the gas source of ozone;the other is aqueous phasechemical reactions which consume ozone in the aqueous phase.Calculations reveal that the reaction O<sub>3</sub>+OH→HO<sub>2</sub> is the main pathway of ozone depletion in gas phase during the process of cumulusclouds.
基金Supported by the NOAA of U.S.(NA18OAR4310298)National Natural Science Foundation of U.S.(AGS-1643297)National Natural Science Foundation of China(41875069).
文摘An operational weather forecast model,coupled to an oceanic model,was used to predict the initiation and propagation of two major Madden–Julian Oscillation(MJO)events during the dynamics of the MJO(DYNAMO)campaign period.Two convective parameterization schemes were used to understand the sensitivity of the forecast to the model cumulus scheme.The first is the Tiedtke(TDK)scheme,and the second is the Simplified Arakawa–Schubert(SAS)scheme.The TDK scheme was able to forecast the MJO-1 and MJO-2 initiation at 15-and45-day lead,respectively,while the SAS scheme failed to predict the convection onset in the western equatorial Indian Ocean(WEIO).The diagnosis of the forecast results indicates that the successful prediction with the TDK scheme is attributed to the model capability to reproduce the observed intraseasonal outgoing longwave radiation–sea surface temperature(OLR–SST)relationship.On one hand,the SST anomaly(SSTA)over the WEIO was induced by surface heat flux anomalies associated with the preceding suppressed-phase MJO.The change of SSTA,in turn,caused boundary layer convergence and ascending motion,which further induced a positive column-integrated moist static energy(MSE)tendency,setting up a convectively unstable stratification for MJO initiation.The forecast with the SAS scheme failed to reproduce the observed OLR–SST–MSE relation.The propagation characteristics differed markedly between the two forecasts.Pronounced eastward phase propagation in the TDK scheme is attributed to a positive zonal gradient of the MSE tendency relative to the MJO center,similar to the observed,whereas a reversed gradient appeared in the forecast with the SAS scheme with dominant westward propagation.The difference is primarily attributed to anomalous vertical and horizontal MSE advection.
基金This work was supported by the "973" Project of the Ministry of Science and Technology (Grant No. G200016107) the National Natural Science Foundation of China (Grant No. 30170679).
文摘It was shown that expansion of porcine cumulus did not depend on oocyte-secreted factor(s), and it is therefore presumed that porcine CEEF may not be produced exclusively by the oocyte. In this experiment, we used mouse oocytectomized complexes (OOX), which were incapable of CEEF production, to assess the secretion of CEEF by evacuated zona, oocytes of different quality and somatic cells in the porcine follicles. The results showed that: (i) Evacuated zonae from both porcine and mouse oocytes did not produce CEEF. (ii) Porcine oocytes of A, B and C types from 3-6 mm follicles were not significantly different in both production and activity of CEEF. (iii) Both porcine OOX from 3-6 mm follicles and granulose cells from 【 1 mm follicles secreted CEEF in a large quantity, independent of gonadotro-pins; mural granulose cells from 3-6 mm follicles, however, produced neglectable amount of CEEF. (iv) The follicular fluid from 3-6 mm porcine follicles contained CEEF activity that was concentration-dependent,
文摘According to the characteristics of cumulus and stratiform clouds during the meiyu period (plum rains) over Jianghuai valleys (the Changjiang (Yangtze) River and the Huaihe River), a modified Kuo-type cumulus parameterization scheme applicable to midlatitude con-vective systems is suggested in this paper. It is often observed that cumulus and stratiform clouds coexist in a rain-bearing synoptic systems and the precipitation amount associated with this system may be amplified by their interaction. With some important processes of cloud physics taken into account, we use a simple seeder-feeder model (including colloidal instability, collision effect and entrainment) to describe this process of interaction within framework of Kuo-type cumulus parameterization. It is found that the rainfall amount caused by ice crystal effect accounts for 30-40% of total rainfall, but the collision effect is not so great generally. We introduced this scheme to the regional numerical model used by Wuhan Observatory of
文摘In this paper, a 1-D time dependent cold cumulus chemistry model is presented. In the coldcumulus model, 4 categories of hydrometeors: cloud drops, raindrops, cloud ice crystals, graupelparticles, and 18 microphysical interactions are considered, In the chemical model, the source andsink terms for pollutants include: the complicated interactions between pollutants (gases andaerosol particles) and the hydrometeors (especially ice crystals and graupel particles), the ex-changes of chemical compounds between two hydrometeors accompanying microphysical processesand the aqueous oxidations of S (IV) to S (VI). The two models are combined to study the acidifi-cation processes in cold cumulus clouds.
基金the authors’lab was supported in parts by the National 973 Project(Nos.2006CB504002 and 2006CB944002)the Focused Investment Scheme on Major Areas of The Chinese University of Hong Kong.
文摘Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the zygote.One of the steps,acrosome reaction(AR),is an exocytosis process,during which the outer acrosome membrane fuses with the inner sperm membrane,leading to the release of acrosome enzymes that facilitate sperm penetration of the egg investments.Though AR has been investigated for decades,the initial steps of AR in vivo,however,remain largely unknown.A well elucidated model holds the view that AR occurs on the surface of the zona pellucida(ZP),which is triggered by binding of sperm with one of the ZP glycosylated protein,ZP3.However,this model fails to explain the large number of‘falsely’acrosome-reacted sperms found within the cumulus layer in many species examined.With the emerging evidence of cross-talk between sperm and cumulus cells,the potential significance of AR in the cumulus oophorus,the outer layer of the egg,has been gradually revealed.Here we review the acrosome status within the cumulus layer,the cross-talk between sperm and cumulus cells with the involvement of a novel spermreleased factor,NYD-SP8,and re-evaluate the importance and physiological significance of the AR in the cumulus in fertilization.
基金Supported by The Key Project from Chinese Technology Department(Project No.2017YFC1001601).
文摘Objective:The transcriptional profile of cumulus cells(CCs)during oocyte maturation provides information for predicting oocyte developmental competence.Our previous study using a mouse model indicated that there were nine different genes related to oocyte development potential expressed in CCs during oocyte maturation.The purpose of this study was to elucidate whether gene expression levels of CCs during oocyte maturation are associated with oocyte developmental competence.Methods:The human CCs collected from each oocyte were divided into two groups after tracking depending on whether or not they developed to the blastocyst stage:(1)the oocytes were developed to blastocyst stage after fertilization(B+)and(2)the oocytes were not developed to blastocyst stage after fertilization(B−).The expression levels of the nine selected genes(ARRB1,ATP2C1,CDH5,CNTNAP1,LGR4,MKLN1,RHOBTB1,SIX2,and SMC2)were examined.CCs were obtained from 29 women who were undergoing intracytoplasmic sperm injection treatment cycles.Quantitative reverse transcriptase-polymerase chain reaction analysis was performed on cumulus masses collected before insemination.Each sample was run three times.Statistically significant differences in mRNA expression of the target genes in independent samples were evaluated by two-tailed Student’s t-test,and P<0.05 was considered significantly different.Results:There were significant differences in the mRNA expression levels of ARRB1(P=0.016),LGR4(P=0.025),and SMC2(P=0.013)between the groups B+and B−.Gene expression of ARRB1,LGR4,and SMC2 in CCs is related to blastocyst development.Conclusions:Analysis of expression of ARRB1,LGR4,and SMC2 genes in CCs as biomarkers may provide predictive information on oocyte developmental competence before insemination and fertilization.
文摘Currently-placed protocols for extended culture for in vitro fertilization(IVF)and intracytoplasmic sperm injection(ICSI)are not uniformly standardized in determining the optimal stage of oocyte maturation for maximizing clinical outcomes.The objective of this systematic review is to elucidate the relationship between extended cumulus-oocyte culture and its effect on the clinical outcomes of IVF/ICSI.We included an electronic search on PubMed Central as well as the Journal of Fertility and Sterility to yield seven studies on extended oocyte culture for IVF/ICSI.Four of the seven investigations illustrate the promising beneficial relationship of extended culture with conditioned or supplemented media to mimic physiological uterine conditions.Three studies did not capture beneficial relationships between extended oocyte culture and clinical outcomes with unconditioned,unsupplemented maturation medium.Improvement in fertilization rates,oocyte development,and live birth rates may be achieved by extended culture with the addition of supplemental biochemicals.The usage of follicular fluid,cumulus cells,and meiotic inhibitors imitates the physiological in vivo conditions,whereas extended oocyte culture imitates in vivo temporal conditions.The conjunction of extended oocyte culture with supplemented metabolites,either added in maturation media manually or secreted by cumulus-oocyte complexes,mimics natural uterine physiological conditions to improve clinical outcomes for patients seeking IVF/ICSI.
文摘The recent progress in the association of cumulus cells with immune functions is a largely ignored area.With over 350 million new sexually transmitted infections occurring annually in adults of reproductive age,we feel the need to explore more about how the cumulus cells defend themselves and protect the oocytes during the development through the ovulation period.Application of assisted reproductive technologies allows scientists to study and better understand cumulus cells.There are still many immune factors to be taken into consideration to optimize the oocyte quality besides ovarian stimulations.The objective of this review is to summarize the key elements of cumulus cells and their association with the immune function.
