Reverse time migration and full waveform inversion involve the crosscorrelation of two wavefields,propagated in the forward-and reverse-time directions,respectively.As a result,the forward-propagated wavefield needs t...Reverse time migration and full waveform inversion involve the crosscorrelation of two wavefields,propagated in the forward-and reverse-time directions,respectively.As a result,the forward-propagated wavefield needs to be stored,and then accessed to compute the correlation with the backward-propagated wavefield.Boundary-value methods reconstruct the source wavefield using saved boundary wavefields and can significantly reduce the storage requirements.However,the existing boundary-value methods are based on the explicit finite-difference(FD)approximations of the spatial derivatives.Implicit FD methods exhibit greater accuracy and thus allow for a smaller operator length.We develop two(an accuracy-preserving and a memory-efficient)wavefield reconstruction schemes based on an implicit staggered-grid FD(SFD)operator.The former uses boundary wavefields at M layers of grid points and the spatial derivatives of wavefields at one layer of grid points to reconstruct the source wavefield for a(2M+2)th-order implicit SFD operator.The latter applies boundary wavefields at N layers of grid points,a linear combination of wavefields at M–N layers of grid points,and the spatial derivatives of wavefields at one layer of grid points to reconstruct the source wavefield(0≤N<M).The required memory of accuracy-preserving and memory-efficient schemes is(M+1)/M and(N+2)/M times,respectively,that of the explicit reconstruction scheme.Numerical results reveal that the accuracy-preserving scheme can achieve accurate reconstruction at the cost of storage.The memory-efficient scheme with N=2 can obtain plausible reconstructed wavefields and images,and the storage amount is 4/(M+1)of the accuracy-preserving scheme.展开更多
Water level fluctuations (WLF) are natural patterns that are necessary for the survival of various plants,and WLF guarantee both the productivity and the biodiversity of wetlands.However,the underlying mechanisms of h...Water level fluctuations (WLF) are natural patterns that are necessary for the survival of various plants,and WLF guarantee both the productivity and the biodiversity of wetlands.However,the underlying mechanisms of how changes in vegetation are linked to seasonal WLF remain unclear.Using vegetation and hydrological data from 1989 to 2009,we identified the key seasonal fluctuations and their impacts on vegetation in the Poyang Lake wetland by utilizing a tree-based hierarchical model.According to our results: 1) WLF in summer had significant impacts on both sedges and reeds.The severe summer floods promoted the expansion of sedges,while they inhibited the expansion of reeds;2) WLF in autumn also greatly impacted sedges,while reeds were severely affected in spring.Specifically,we found that low water levels in autumn led to the expansion of sedges,and low water levels in spring led to the expansion of reeds.The results were well corroborated through comparisons of the vegetation distribution patterns over the last two decades (i.e.,the 1990s and 2000s),which may shed light on corresponding water resource and wetland management.展开更多
Objective To investigate the neuroprotective effects and the mechanism of this protection of raloxifene （RLX）, a selective estrogen receptor modulator.Methods MTT assay and flow cytometry with annexin V-FITC/PI stai...Objective To investigate the neuroprotective effects and the mechanism of this protection of raloxifene （RLX）, a selective estrogen receptor modulator.Methods MTT assay and flow cytometry with annexin V-FITC/PI staining were performed to evaluate the neuroprotective effects of RLX on Aβ25-35-induced toxicity. The potential mechanisms were studied by Western blotting in cultured rat pheochromocytoma cells （PC12 cells）.Results RLX（1 000 nmol/L）, in combination with Aβ25-35 （30 llmol/L）, increased the cell viability （P 〈0.001）, and reduced the number of apoptotic cells （P 〈0.05）. RLX attenuated Aβ25-35-induced loss of △ψm （P 〈0.01）. The changing of △ψm was similar to the variation of apoptosis. PD98059 （inhibitor of ERK1/2） inhibited the effects of RLX on cell viability and phosphorylation of cleaved caspase-9. No significant difference of cell viability or phosphorylation of cleaved caspase-9 had been found when PC12 cells were incubated with SB203580 （inhibitor of p38MAPK） or SP600125 （inhibitor of JNK）. Afl25.35 induced a time-dependent phosphorylation of p38MAPK and JNK. In PC12 cells treated solely with RLX, ERK1/2 was activated （P〈0.01）. In PC12 cells treated with Aβ25-35 and RLX, Aβ2545-induced phosphorylation of p38MAPK and JNK were inhibited （P〈0.01 and P〈0.001, respectively）.Conclusion RLX inhibited Af125.35-induced cell apoptosis by activating the ERK1/2 pathway in PC12 cells. RLX also attenuated Aβ25-35-induced activation of p38MAPK and JNK. The mitochondria pathway Was involved in this inhibitory effect.展开更多
Objective:The purpose of this study was to evaluate the sperm motility and DNA integrity at different temperatures to analyze whether the sperms are suitable on the second day for insemination of in vitro matured oocy...Objective:The purpose of this study was to evaluate the sperm motility and DNA integrity at different temperatures to analyze whether the sperms are suitable on the second day for insemination of in vitro matured oocytes by intra-cytoplasmic sperm injection(ICSI)following density gradient centrifugation(DGC)and swim-up(SU)procedures.Methods:Semen samples were collected from 30 outpatients who visited the Center for Reproductive Medicine for semen analyses.Following sperm selection by DGC and SU procedures,the liquified semen samples were divided into three groups and incubated at 4,25,and 37°C,respectively.Following incubation for 24,48,and 72 hours,the sperm motility and sperm DNA fragmentation index(DFI)were analyzed.Results:Following the combination of DGC and SU procedures,the sperm motility(91.8%±8.6%vs.50.8%±13.1%)and DFI(5.1%±7.9%vs.13.0%±11.6%)were significantly improved(P<0.01)compared to those without any treatment.The sperm motility of the 3 groups significantly declined(P<0.05)post-incubation compared to that of the groups prior incubation.However,sperm motility significantly increased(76.9%±10.4%)(P<0.05)at 25°C compared to that of the other 2 groups(53.5%±11.0%and 47.6%±10.2%).Sperm DFI significantly increased(P<0.05)at 37°C following incubation for 24 and 72 hours in comparison to that of the other 2 groups.However,the sperm DFI did not significantly increase when the sperm samples were incubated at 4(5.7%±5.9%)and 25°C(6.8%±5.6%)for 24 hours compared to that before incubation(5.1%±7.9%).Conclusions:These results indicate that the sperm quality,in terms of motility and DFI,can be efficiently improved by DGC in combination with SU.Following which,the sperm samples can be incubated at 25°C and be used on the second day for insemination of in vitro matured oocytes by ICSI.展开更多
Objective To identify efficient predictors of clinical outcomes of in vitro fertilization （IVF）. Methods Two hundred and one women undergoing their first IVF cycle were measured for antral follicle count （AFC） and...Objective To identify efficient predictors of clinical outcomes of in vitro fertilization （IVF）. Methods Two hundred and one women undergoing their first IVF cycle were measured for antral follicle count （AFC） and endometrial thickness via ultrasound. On day 2 or 3 of the menstrual cycle and the day of human chorionic gonadotropin administration, serum levels of follicle-stimulating hormone （FSH）, luteinizing hormone （LH）, estradiol, and progesterone were determined. The difference of ovarian response and clinical pregnancy rates were measured. Results Basal FSH was the single best predictor of ovarian response in women 〈35 years old before the initiation of treatment, with an area under the receiver operating characteristic curve （A UC） of 0. 752. For women ≥ 35 years old, none of parameters was a single good predictor of lVF pregnancy. For women older than 35 years, adding body mass index （BMI） with AFC and basal FSH improved prediction of ovarian response （A UC=0. 859）. Prediction of clinical pregnancy for women ≥ 35 years was improved either by combining only AFC and basal FSH （AUC=0. 757） or adding BMI to the combined AFC and FSH （AUC=0. 722）. Conclusion Combining AFC, basal FSH, and BMI was the best predictor of ovarian response and clinical pregnancy after IVF in women ≥ 35 years.展开更多
基金partially supported by National Key R&D Program of China(2021YFA0716902)the National Natural Science Foundation of China(42174156)the Fundamental Research Funds for the Central Universities,CHD(300102261107)。
文摘Reverse time migration and full waveform inversion involve the crosscorrelation of two wavefields,propagated in the forward-and reverse-time directions,respectively.As a result,the forward-propagated wavefield needs to be stored,and then accessed to compute the correlation with the backward-propagated wavefield.Boundary-value methods reconstruct the source wavefield using saved boundary wavefields and can significantly reduce the storage requirements.However,the existing boundary-value methods are based on the explicit finite-difference(FD)approximations of the spatial derivatives.Implicit FD methods exhibit greater accuracy and thus allow for a smaller operator length.We develop two(an accuracy-preserving and a memory-efficient)wavefield reconstruction schemes based on an implicit staggered-grid FD(SFD)operator.The former uses boundary wavefields at M layers of grid points and the spatial derivatives of wavefields at one layer of grid points to reconstruct the source wavefield for a(2M+2)th-order implicit SFD operator.The latter applies boundary wavefields at N layers of grid points,a linear combination of wavefields at M–N layers of grid points,and the spatial derivatives of wavefields at one layer of grid points to reconstruct the source wavefield(0≤N<M).The required memory of accuracy-preserving and memory-efficient schemes is(M+1)/M and(N+2)/M times,respectively,that of the explicit reconstruction scheme.Numerical results reveal that the accuracy-preserving scheme can achieve accurate reconstruction at the cost of storage.The memory-efficient scheme with N=2 can obtain plausible reconstructed wavefields and images,and the storage amount is 4/(M+1)of the accuracy-preserving scheme.
基金the National Key Research and Development Project of China (No.2016YFC0402204)the National Natural Science Foundation of China (Grant No.41571107)+1 种基金the Key Research Program of the Chinese Academy of Sciences (No.KFZD-SW-318)the Key Project of Water Resources Department of Jiangxi Province (No.KT201503).
文摘Water level fluctuations (WLF) are natural patterns that are necessary for the survival of various plants,and WLF guarantee both the productivity and the biodiversity of wetlands.However,the underlying mechanisms of how changes in vegetation are linked to seasonal WLF remain unclear.Using vegetation and hydrological data from 1989 to 2009,we identified the key seasonal fluctuations and their impacts on vegetation in the Poyang Lake wetland by utilizing a tree-based hierarchical model.According to our results: 1) WLF in summer had significant impacts on both sedges and reeds.The severe summer floods promoted the expansion of sedges,while they inhibited the expansion of reeds;2) WLF in autumn also greatly impacted sedges,while reeds were severely affected in spring.Specifically,we found that low water levels in autumn led to the expansion of sedges,and low water levels in spring led to the expansion of reeds.The results were well corroborated through comparisons of the vegetation distribution patterns over the last two decades (i.e.,the 1990s and 2000s),which may shed light on corresponding water resource and wetland management.
基金supported by the "Six Talents Peak" of Jiangsu Province,China 973 Program(No.2007CB944005)Science and Technology Development Foundation of Nanjing Medical University(No.2011NJMU152)
文摘Objective To investigate the neuroprotective effects and the mechanism of this protection of raloxifene （RLX）, a selective estrogen receptor modulator.Methods MTT assay and flow cytometry with annexin V-FITC/PI staining were performed to evaluate the neuroprotective effects of RLX on Aβ25-35-induced toxicity. The potential mechanisms were studied by Western blotting in cultured rat pheochromocytoma cells （PC12 cells）.Results RLX（1 000 nmol/L）, in combination with Aβ25-35 （30 llmol/L）, increased the cell viability （P 〈0.001）, and reduced the number of apoptotic cells （P 〈0.05）. RLX attenuated Aβ25-35-induced loss of △ψm （P 〈0.01）. The changing of △ψm was similar to the variation of apoptosis. PD98059 （inhibitor of ERK1/2） inhibited the effects of RLX on cell viability and phosphorylation of cleaved caspase-9. No significant difference of cell viability or phosphorylation of cleaved caspase-9 had been found when PC12 cells were incubated with SB203580 （inhibitor of p38MAPK） or SP600125 （inhibitor of JNK）. Afl25.35 induced a time-dependent phosphorylation of p38MAPK and JNK. In PC12 cells treated solely with RLX, ERK1/2 was activated （P〈0.01）. In PC12 cells treated with Aβ25-35 and RLX, Aβ2545-induced phosphorylation of p38MAPK and JNK were inhibited （P〈0.01 and P〈0.001, respectively）.Conclusion RLX inhibited Af125.35-induced cell apoptosis by activating the ERK1/2 pathway in PC12 cells. RLX also attenuated Aβ25-35-induced activation of p38MAPK and JNK. The mitochondria pathway Was involved in this inhibitory effect.
基金Ministry of Science and Technology of China,National Key R&D Program of China(No.2017YFC1002003 and No.2017YFC1001601)
文摘Objective:The purpose of this study was to evaluate the sperm motility and DNA integrity at different temperatures to analyze whether the sperms are suitable on the second day for insemination of in vitro matured oocytes by intra-cytoplasmic sperm injection(ICSI)following density gradient centrifugation(DGC)and swim-up(SU)procedures.Methods:Semen samples were collected from 30 outpatients who visited the Center for Reproductive Medicine for semen analyses.Following sperm selection by DGC and SU procedures,the liquified semen samples were divided into three groups and incubated at 4,25,and 37°C,respectively.Following incubation for 24,48,and 72 hours,the sperm motility and sperm DNA fragmentation index(DFI)were analyzed.Results:Following the combination of DGC and SU procedures,the sperm motility(91.8%±8.6%vs.50.8%±13.1%)and DFI(5.1%±7.9%vs.13.0%±11.6%)were significantly improved(P<0.01)compared to those without any treatment.The sperm motility of the 3 groups significantly declined(P<0.05)post-incubation compared to that of the groups prior incubation.However,sperm motility significantly increased(76.9%±10.4%)(P<0.05)at 25°C compared to that of the other 2 groups(53.5%±11.0%and 47.6%±10.2%).Sperm DFI significantly increased(P<0.05)at 37°C following incubation for 24 and 72 hours in comparison to that of the other 2 groups.However,the sperm DFI did not significantly increase when the sperm samples were incubated at 4(5.7%±5.9%)and 25°C(6.8%±5.6%)for 24 hours compared to that before incubation(5.1%±7.9%).Conclusions:These results indicate that the sperm quality,in terms of motility and DFI,can be efficiently improved by DGC in combination with SU.Following which,the sperm samples can be incubated at 25°C and be used on the second day for insemination of in vitro matured oocytes by ICSI.
基金supported by the open fund from State Key Laboratory of Reproductive Medicine in Nanjing Medical University(No.SKLRM-KF-1210)
文摘Objective To identify efficient predictors of clinical outcomes of in vitro fertilization （IVF）. Methods Two hundred and one women undergoing their first IVF cycle were measured for antral follicle count （AFC） and endometrial thickness via ultrasound. On day 2 or 3 of the menstrual cycle and the day of human chorionic gonadotropin administration, serum levels of follicle-stimulating hormone （FSH）, luteinizing hormone （LH）, estradiol, and progesterone were determined. The difference of ovarian response and clinical pregnancy rates were measured. Results Basal FSH was the single best predictor of ovarian response in women 〈35 years old before the initiation of treatment, with an area under the receiver operating characteristic curve （A UC） of 0. 752. For women ≥ 35 years old, none of parameters was a single good predictor of lVF pregnancy. For women older than 35 years, adding body mass index （BMI） with AFC and basal FSH improved prediction of ovarian response （A UC=0. 859）. Prediction of clinical pregnancy for women ≥ 35 years was improved either by combining only AFC and basal FSH （AUC=0. 757） or adding BMI to the combined AFC and FSH （AUC=0. 722）. Conclusion Combining AFC, basal FSH, and BMI was the best predictor of ovarian response and clinical pregnancy after IVF in women ≥ 35 years.
