Mole rat （Scaptochirus moschatus）, a soil-burrowing mammal, can efficiently dig soil using its fore claws. The profile curves of its claw toe provide excellent structure for digging. In this paper, a biomimetic stub...Mole rat （Scaptochirus moschatus）, a soil-burrowing mammal, can efficiently dig soil using its fore claws. The profile curves of its claw toe provide excellent structure for digging. In this paper, a biomimetic stubble-cutting disc was designed by learning from the geometrical characteristics of the mole rat claw toes. To compare the structural strength and working eff^- ciency of the biomimetic disc and the conventional stubble-cutting disc, three-dimensional （3D） models of the discs were built and numerical analyzed in ABAQUS. In the dynamic soil cutting model, soil was modeled as an elastic-plastic material with elastic parameters, including Young＇s modulus, Poisson＇s ratio and Drucker-Prager criterion, which were obtained from triaxial tests. A general contact algorithm was used to simulate the interaction between rotary disc and soil. In FEA models, for the combined action of normal and friction stresses, the stress on the biomimetic disc is 34.33% lower than that of the conventional disc. For only the normal stress, the stress on the biomimetic disc is 22.64% lower than that on the conventional one. The magnitude of soil stress in biomimetie disc cutting model is 6.87% higher than that in conventional disc. The FEA results indicate that the biomimetic disc performs better in structural strength and cutting efficiency.展开更多
The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich corner was investigated by XRD and SEM/EDS analysis and was further explain...The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich corner was investigated by XRD and SEM/EDS analysis and was further explained from the ternary phase diagram calculation. The results show that the formation of the secondary phases in Mg-Zn-Y-Zr alloys firmly depends on the mole ratio of Y to Zn, and X （Mg 12 YZn）-phase, W （Mg 3 Y 2 Zn 3 ）-phase and I （Mg 3 YZn 6 ）-phase come out in sequence as the ratio of Y to Zn decreases. The mole ratios of Y to Zn with the corresponding phase constituent are suggested quantitatively as follows： the phase constituent is α-Mg ＋ I when the mole ratio of Y to Zn is about 0.164; α-Mg ＋ I ＋W when the mole ratio of Y to Zn is in the range of 0.164 0.33;α-Mg ＋W when the mole ratio of Y to Zn is about 0.33; α-Mg ＋W＋X when the mole ratio of Y to Zn is in the range of 0.33 1.32; and α-Mg ＋X when the mole ratio of Y to Zn is about 1.32. The results also offer a guideline for alloy selection and alloy design in Mg-Zn-Y-Zr system.展开更多
Gestational trophoblastic neoplasia(GTN) is a rare tumor that originates from pregnancy that includes invasive mole, choriocarcinoma(CCA), placental site trophoblastic tumor and epithelioid trophoblastic tumor(PSTT/ET...Gestational trophoblastic neoplasia(GTN) is a rare tumor that originates from pregnancy that includes invasive mole, choriocarcinoma(CCA), placental site trophoblastic tumor and epithelioid trophoblastic tumor(PSTT/ETT). GTN presents different degrees of proliferation, invasion and dissemination, but, if treated in reference centers, has high cure rates, even in multi-metastatic cases.The diagnosis of GTN following a hydatidiform molar pregnancy is made according to the International Federation of Gynecology and Obstetrics(FIGO)2000 criteria: four or more plateaued human chorionic gonadotropin(hCG)concentrations over three weeks; rise in hCG for three consecutive weekly measurements over at least a period of 2 weeks or more; and an elevated but falling hCG concentrations six or more months after molar evacuation. However,the latter reason for treatment is no longer used by many centers. In addition,GTN is diagnosed with a pathological diagnosis of CCA or PSTT/ETT. For staging after a molar pregnancy, FIGO recommends pelvic-transvaginal Doppler ultrasound and chest X-ray. In cases of pulmonary metastases with more than 1cm, the screening should be complemented with chest computed tomography and brain magnetic resonance image. Single agent chemotherapy, usually Methotrexate(MTX) or Actinomycin-D(Act-D), can cure about 70% of patients with FIGO/World Health Organization(WHO) prognosis risk score ≤ 6(low risk), reserving multiple agent chemotherapy, such as EMA/CO(Etoposide,MTX, Act-D, Cyclophosphamide and Oncovin) for cases with FIGO/WHO prognosis risk score ≥ 7(high risk) that is often metastatic. Best overall cure rates for low and high risk disease is close to 100% and > 95%, respectively. The management of PSTT/ETT differs and cure rates tend to be a bit lower. The early diagnosis of this disease and the appropriate treatment avoid maternal death,allow the healing and maintenance of the reproductive potential of these women.展开更多
To develop super-high strength Al-Li alloy,the microstructures and mechanical properties of Mg,Ag and Zn microalloyed Al-（3.2-3.8）Cu-（1.0-1.4）Li alloys（mass fraction） with T8 temper were studied.The results show...To develop super-high strength Al-Li alloy,the microstructures and mechanical properties of Mg,Ag and Zn microalloyed Al-（3.2-3.8）Cu-（1.0-1.4）Li alloys（mass fraction） with T8 temper were studied.The results showed that 1%of lower Li content restricted the strengthening effect of increasing Cu content,while simultaneous increase in Cu and Li contents contributed effectively to the enhancement of strength.The alloys were mainly strengthened by plenty of fine and well dispersed TI（Al2CuLi）precipitates.There were also some minor precipitates of θ＇（Al2Cu） and δ＇（Al3Li）,which became less in number density,even disappeared during the aging process.Meanwhile,higher Li content favored the formation θ＇ and δ＇ and a small amount of S＂（Al2CuMg） phases.In addition,strengthening effect and microstructure variation were analyzed through total non-solution mole fraction of Cu and Li and their mole ratio.To obtain Al-Li alloy with super-high strength,the total mole fractions of Cu and Li should be increased,and their mole ratios should also be kept at a certain high level.展开更多
The fore leg of mole cricket （Orthoptera： Glyllotalpidae） has developed into claw for digging and excavating. As the result of having a well-suited body and appendages for living underground, mole cricket still nee...The fore leg of mole cricket （Orthoptera： Glyllotalpidae） has developed into claw for digging and excavating. As the result of having a well-suited body and appendages for living underground, mole cricket still needs to manoeuvre on land in some cases with some kinds of gait. In this paper, the three-dimensional kinematics information of mole cricket in terrestrial walking was recorded by using a high speed 3D video recording system. The mode and the gait of the terrestrial walking mole cricket were investigated by analyzing the kinematics parameters, and the kinematics coupling disciplines of each limb and body were discussed. The results show that the locomotion gait of mole cricket in terrestrial walking belongs to a distinctive alternating tripod gait. We also found that the fore legs of a mole cricket are not as effective as that of common hexapod insects, its middle legs and body joints act more effective in walking and turning which compensate the function of fore legs. The terrestrial lo-comotion of mole cricket is the result of biological coupling of three pairs of legs, the distinctive alternating tripod gait and the trunk locomotion.展开更多
Biomimetic blades for soil-rototilling and stubble-breaking were designed learning from the geometrical structure of the tips of toes of mole rat （Scaptochirus moschatus）. The orientation, the number and the central...Biomimetic blades for soil-rototilling and stubble-breaking were designed learning from the geometrical structure of the tips of toes of mole rat （Scaptochirus moschatus）. The orientation, the number and the central angle of the biomimetic structure were taken as the testing factors. The optimal structure of the biomimetic blade was determined through the tests of soil-rototilling and stubble-breaking operation in an indoor soil bin. The optimal combination of the biomimetic structure pa- rameters is that three arc concave teeth are equally arranged on the front cutting edge with a central angle of 60°. The results of comparative tests between the optimal biomimetic blade and a conventional universal blade show the torque acting on the biomimetic blade is lower during soil-rototilling and stubble-breaking operations. The results of field tests show that the working quality of the biomimetic blades meets the requirements of the national standard of China. Tests of soil-rototilling show that, when the orientation of the biomimetic structure was at low and middle levels, the torque ofbiomimetic blades decreased from 34.17 N·m to 31.03 N·m. The torque also decreased with the increase of the number of biomimetic structure. The average torques were 34.57 N·m, 33.44 N·m and 31.37 N·m, respectively. The maximum different value between two levels of central angle was 0.41 N·m. Tests in field indicate that for soil-rototilling operation, the tillage depth is deeper than 80 mm, the soil-crushing rate （length of soil block less than 40 mm） is over 50 %, and the vegetation coverage rate is over 55 %. For stubble-breaking operation, the stubble-breaking depth is deeper than 70 ram, the stubble-breaking rate （length of stubble less than 40 mm） is over 60%, and the stubble coverage rate is over 80%, which can meet the stubble-breaking requirement of corn.展开更多
Gestational trophoblastic disease is an abnormal proliferation of trophoblastic tissue during pregnancy. It occurs in women of childbearing age, although a few cases have also been observed in post-menopausal women, a...Gestational trophoblastic disease is an abnormal proliferation of trophoblastic tissue during pregnancy. It occurs in women of childbearing age, although a few cases have also been observed in post-menopausal women, although it is extremely rare in the latter. Here we describe a rare case of complete hydatidiform mole in a 56-year-old female patient who presented with genital bleeding combined with nausea and vomiting and a gravid uterus 16 cm in height. The ultrasound findings and the increase in serum β-HCG to 182566.00 mIU/ml suggested a diagnosis of complete hydatidiform mole. Given the post-menopausal state and the future risk of post-molar gestational trophoblastic neoplasia, we opted for total hysterectomy without preservation of the adnexa via a transabdominal approach, followed by antimitotic treatment with methotrexate. The uterus measured 18.45 cm × 11.18 cm with intra cavitary vesicles. Microscopic examination showed chorionic villi of variable size and shape, most of which were dilated and oedematous, associated with trophoblastic cell proliferation and haemorrhage suggestive of complete benign hydatidiform mole. Follow-up showed a consistent decrease in serum β-HCG levels and no evidence of residual disease. A suspicion of gestational trophoblastic disease should be borne in mind when evaluating a patient with peri- or post-menopausal bleeding to avoid delay in diagnosis and treatment.展开更多
In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed red...In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.展开更多
Gas washing has been known in the Tazhong area of the Tarim Basin,but its quantitative assessment has not yet been reported.Here the influence of gas washing fractionation in the area was discussed based on the gas ch...Gas washing has been known in the Tazhong area of the Tarim Basin,but its quantitative assessment has not yet been reported.Here the influence of gas washing fractionation in the area was discussed based on the gas chromatogram data of 68 oils and the results of the mixing experiments of a black oil and a condensate.The results show that the intensity of gas washing fractionation decreased generally from northern to southern part and vertically from deep reservoirs to shallow reservoirs.The gas washing fractionation was mainly controlled by fault systems in this area,with the increase of n-alkane mass depletion positively correlated to the number and scale of faults.Gas washing fractionation appears to have affected the hydrocarbon property,and as a result the diversity of the crude oils is markedly controlled by gas washing.In addition,the occurrence of waxy oil in this area may be resulted from multiple factors including gas washing,mixed filling and migration fractionation.展开更多
Twin pregnancy with mosaic partial hydatidiform mole （PHM） and survival of two healthy fetuses following in vitro fertilization and embryos transfer （IVF-ET） is a rare situation and is considered a challenge for m...Twin pregnancy with mosaic partial hydatidiform mole （PHM） and survival of two healthy fetuses following in vitro fertilization and embryos transfer （IVF-ET） is a rare situation and is considered a challenge for management. A 32-year-old Chinese woman conceived twin pregnancy following IVF-ET. At 22 weeks＇ gestation, an additional intrauterine echogenic mass with features of PHM were shown by successive ultrasound examinations. At 35 weeks＇ gestation, two live male infants and two placentas were delivered by caesarean section （CS）. Histologic examination of the abnormal placenta confirmed mosaic PHM. Genetic study showed the abnormal placental mosaicism （expressed in molar-69XXY and normal vili-46XY）, co-existing with a hypospadia new-born （46XY） in one amniotic sac. However, the other one was normal. Serial serum β-hCG levels showed a declining trend and serum β-human chorionic gonadotropin （hCG） were undetectable at 6 months after delivery. The case demonstrated that it is possible to prolonged gestation by PHM under close surveillance during the entire pregnancy.展开更多
A molten salt reactor(MSR)has outstanding features considering the application of thorium fuel,inherent safety,sustainability,and resistance to proliferation.However,fissile material^(233)U is significantly rare at th...A molten salt reactor(MSR)has outstanding features considering the application of thorium fuel,inherent safety,sustainability,and resistance to proliferation.However,fissile material^(233)U is significantly rare at the current stage,thus it is difficult for MSR to achieve a pure thorium-uranium fuel cycle.Therefore,using plutonium or enriched uranium as the initial fuel for MSR is more practical.In this study,we aim to verify the feasibility of a small modular MSR that utilizes plutonium as the starting fuel(SM-MSR-Pu),and highlight its advantages and disadvantages.First,the structural design and fuel management scheme of the SM-MSR-Pu were presented.Second,the neutronic characteristics,such as the graphite-irradiation lifetime,burn-up performance,and coefficient of temperature reactivity were calculated to analyze the physical characteristics of the SM-MSR-Pu.The results indicate that plutonium is a feasible and advantageous starting fuel for a SM-MSR;however,there are certain shortcomings that need to be solved.In a 250 MWth SM-MSR-Pu,approximately 288.64 kg^(233)U of plutonium with a purity of greater than 90% is produced while 978.00 kg is burned every ten years.The temperature reactivity coefficient decreases from -4.0 to -6.5 pcm K^(-1) over the 50-year operating time,which ensures a long-term safe operation.However,the amount of plutonium and accumulation of minor actinides(MAs)would increase as the burn-up time increases,and the annual production and purity of^(233)U will decrease.To achieve an optimal burn-up performance,setting the entire operation time to 30 years is advisable.Regardless,more than 3600 kg of plutonium eventually accumulate in the core.Further research is required to effectively utilize this accumulated plutonium.展开更多
Invasive mole is a rare subgroup of gestational trophoblastic disease characterized by the invasion of molar tissue into the myometrium or uterine vasculature. In this paper, we report the third case of invasive mole ...Invasive mole is a rare subgroup of gestational trophoblastic disease characterized by the invasion of molar tissue into the myometrium or uterine vasculature. In this paper, we report the third case of invasive mole described in the Malagasy literature. A 33-year-old woman was referred to the Soavinandriana Hospital, her complaint was persistent vaginal bleeding during 2 months, occurring at 3 months of pregnancy with biological anemia without hemodynamic repercussions. The human chorionic gonadotropin (HCG) level was 385,931 mIU/ml. A haemostasis hysterectomy was performed. Histological examination showed an enlarged uterus and endometrial cavity containing edematous chorionic villi with trophoblastic proliferation invading the myometrium. The diagnosis was an invasive mole, stage I, FIGO score 6. Chemotherapy was prescribed but was not honored. After 45 days of follow-up, the serum βHCG level decreased to 1803 mIU/ml, without clinical symptoms. The patient then lost sight. Persistent vaginal bleeding after pregnancy may be the only clinical symptom of an invasive mole and should raise suspicion. Histological examination establishes the diagnosis. As this is an unusual cause of vaginal bleeding, our case should remind physicians that when faced with this symptom, the possibility of an invasive mole should be considered in order to make an early diagnosis for less aggressive treatment.展开更多
基金the National Natural Science Foundation of China，the Development Programme of Science and Technology of Jilin Province of China，the National "985 Project" in Jilin University,China,and the Graduate Innovation Fund of Jilin University
文摘Mole rat （Scaptochirus moschatus）, a soil-burrowing mammal, can efficiently dig soil using its fore claws. The profile curves of its claw toe provide excellent structure for digging. In this paper, a biomimetic stubble-cutting disc was designed by learning from the geometrical characteristics of the mole rat claw toes. To compare the structural strength and working eff^- ciency of the biomimetic disc and the conventional stubble-cutting disc, three-dimensional （3D） models of the discs were built and numerical analyzed in ABAQUS. In the dynamic soil cutting model, soil was modeled as an elastic-plastic material with elastic parameters, including Young＇s modulus, Poisson＇s ratio and Drucker-Prager criterion, which were obtained from triaxial tests. A general contact algorithm was used to simulate the interaction between rotary disc and soil. In FEA models, for the combined action of normal and friction stresses, the stress on the biomimetic disc is 34.33% lower than that of the conventional disc. For only the normal stress, the stress on the biomimetic disc is 22.64% lower than that on the conventional one. The magnitude of soil stress in biomimetie disc cutting model is 6.87% higher than that in conventional disc. The FEA results indicate that the biomimetic disc performs better in structural strength and cutting efficiency.
基金Project(50725413)supported by the National Natural Science Foundation of China
文摘The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich corner was investigated by XRD and SEM/EDS analysis and was further explained from the ternary phase diagram calculation. The results show that the formation of the secondary phases in Mg-Zn-Y-Zr alloys firmly depends on the mole ratio of Y to Zn, and X （Mg 12 YZn）-phase, W （Mg 3 Y 2 Zn 3 ）-phase and I （Mg 3 YZn 6 ）-phase come out in sequence as the ratio of Y to Zn decreases. The mole ratios of Y to Zn with the corresponding phase constituent are suggested quantitatively as follows： the phase constituent is α-Mg ＋ I when the mole ratio of Y to Zn is about 0.164; α-Mg ＋ I ＋W when the mole ratio of Y to Zn is in the range of 0.164 0.33;α-Mg ＋W when the mole ratio of Y to Zn is about 0.33; α-Mg ＋W＋X when the mole ratio of Y to Zn is in the range of 0.33 1.32; and α-Mg ＋X when the mole ratio of Y to Zn is about 1.32. The results also offer a guideline for alloy selection and alloy design in Mg-Zn-Y-Zr system.
文摘Gestational trophoblastic neoplasia(GTN) is a rare tumor that originates from pregnancy that includes invasive mole, choriocarcinoma(CCA), placental site trophoblastic tumor and epithelioid trophoblastic tumor(PSTT/ETT). GTN presents different degrees of proliferation, invasion and dissemination, but, if treated in reference centers, has high cure rates, even in multi-metastatic cases.The diagnosis of GTN following a hydatidiform molar pregnancy is made according to the International Federation of Gynecology and Obstetrics(FIGO)2000 criteria: four or more plateaued human chorionic gonadotropin(hCG)concentrations over three weeks; rise in hCG for three consecutive weekly measurements over at least a period of 2 weeks or more; and an elevated but falling hCG concentrations six or more months after molar evacuation. However,the latter reason for treatment is no longer used by many centers. In addition,GTN is diagnosed with a pathological diagnosis of CCA or PSTT/ETT. For staging after a molar pregnancy, FIGO recommends pelvic-transvaginal Doppler ultrasound and chest X-ray. In cases of pulmonary metastases with more than 1cm, the screening should be complemented with chest computed tomography and brain magnetic resonance image. Single agent chemotherapy, usually Methotrexate(MTX) or Actinomycin-D(Act-D), can cure about 70% of patients with FIGO/World Health Organization(WHO) prognosis risk score ≤ 6(low risk), reserving multiple agent chemotherapy, such as EMA/CO(Etoposide,MTX, Act-D, Cyclophosphamide and Oncovin) for cases with FIGO/WHO prognosis risk score ≥ 7(high risk) that is often metastatic. Best overall cure rates for low and high risk disease is close to 100% and > 95%, respectively. The management of PSTT/ETT differs and cure rates tend to be a bit lower. The early diagnosis of this disease and the appropriate treatment avoid maternal death,allow the healing and maintenance of the reproductive potential of these women.
基金Project(2013AA032401)supported by the National High-tech Research and Development Program of ChinaProject(2013JSJJ 001)supported by Teacher's Research Foundation of Central South University,China
文摘To develop super-high strength Al-Li alloy,the microstructures and mechanical properties of Mg,Ag and Zn microalloyed Al-（3.2-3.8）Cu-（1.0-1.4）Li alloys（mass fraction） with T8 temper were studied.The results showed that 1%of lower Li content restricted the strengthening effect of increasing Cu content,while simultaneous increase in Cu and Li contents contributed effectively to the enhancement of strength.The alloys were mainly strengthened by plenty of fine and well dispersed TI（Al2CuLi）precipitates.There were also some minor precipitates of θ＇（Al2Cu） and δ＇（Al3Li）,which became less in number density,even disappeared during the aging process.Meanwhile,higher Li content favored the formation θ＇ and δ＇ and a small amount of S＂（Al2CuMg） phases.In addition,strengthening effect and microstructure variation were analyzed through total non-solution mole fraction of Cu and Li and their mole ratio.To obtain Al-Li alloy with super-high strength,the total mole fractions of Cu and Li should be increased,and their mole ratios should also be kept at a certain high level.
基金Acknowledgement This work was supported by the National Natural Science Foundation （Grant No. 50635030）.
文摘The fore leg of mole cricket （Orthoptera： Glyllotalpidae） has developed into claw for digging and excavating. As the result of having a well-suited body and appendages for living underground, mole cricket still needs to manoeuvre on land in some cases with some kinds of gait. In this paper, the three-dimensional kinematics information of mole cricket in terrestrial walking was recorded by using a high speed 3D video recording system. The mode and the gait of the terrestrial walking mole cricket were investigated by analyzing the kinematics parameters, and the kinematics coupling disciplines of each limb and body were discussed. The results show that the locomotion gait of mole cricket in terrestrial walking belongs to a distinctive alternating tripod gait. We also found that the fore legs of a mole cricket are not as effective as that of common hexapod insects, its middle legs and body joints act more effective in walking and turning which compensate the function of fore legs. The terrestrial lo-comotion of mole cricket is the result of biological coupling of three pairs of legs, the distinctive alternating tripod gait and the trunk locomotion.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 51475204, 51105161）, the National Agricultural Technology Transformation Foundation of China （Grant No. 2013GB23600661）, the Natural Science Foundation of Hubei Province of China （Grant No. 2011CDB 149）, the Fundamental Research Funds for the Central Universities （Grant No. 2011QC009）, the Startup Foundation for Doctors of Huazhong Agricultural University （Grant No. 2010BQ009）, and the ＂National 985 Project＂ in Jilin University, China.
文摘Biomimetic blades for soil-rototilling and stubble-breaking were designed learning from the geometrical structure of the tips of toes of mole rat （Scaptochirus moschatus）. The orientation, the number and the central angle of the biomimetic structure were taken as the testing factors. The optimal structure of the biomimetic blade was determined through the tests of soil-rototilling and stubble-breaking operation in an indoor soil bin. The optimal combination of the biomimetic structure pa- rameters is that three arc concave teeth are equally arranged on the front cutting edge with a central angle of 60°. The results of comparative tests between the optimal biomimetic blade and a conventional universal blade show the torque acting on the biomimetic blade is lower during soil-rototilling and stubble-breaking operations. The results of field tests show that the working quality of the biomimetic blades meets the requirements of the national standard of China. Tests of soil-rototilling show that, when the orientation of the biomimetic structure was at low and middle levels, the torque ofbiomimetic blades decreased from 34.17 N·m to 31.03 N·m. The torque also decreased with the increase of the number of biomimetic structure. The average torques were 34.57 N·m, 33.44 N·m and 31.37 N·m, respectively. The maximum different value between two levels of central angle was 0.41 N·m. Tests in field indicate that for soil-rototilling operation, the tillage depth is deeper than 80 mm, the soil-crushing rate （length of soil block less than 40 mm） is over 50 %, and the vegetation coverage rate is over 55 %. For stubble-breaking operation, the stubble-breaking depth is deeper than 70 ram, the stubble-breaking rate （length of stubble less than 40 mm） is over 60%, and the stubble coverage rate is over 80%, which can meet the stubble-breaking requirement of corn.
文摘Gestational trophoblastic disease is an abnormal proliferation of trophoblastic tissue during pregnancy. It occurs in women of childbearing age, although a few cases have also been observed in post-menopausal women, although it is extremely rare in the latter. Here we describe a rare case of complete hydatidiform mole in a 56-year-old female patient who presented with genital bleeding combined with nausea and vomiting and a gravid uterus 16 cm in height. The ultrasound findings and the increase in serum β-HCG to 182566.00 mIU/ml suggested a diagnosis of complete hydatidiform mole. Given the post-menopausal state and the future risk of post-molar gestational trophoblastic neoplasia, we opted for total hysterectomy without preservation of the adnexa via a transabdominal approach, followed by antimitotic treatment with methotrexate. The uterus measured 18.45 cm × 11.18 cm with intra cavitary vesicles. Microscopic examination showed chorionic villi of variable size and shape, most of which were dilated and oedematous, associated with trophoblastic cell proliferation and haemorrhage suggestive of complete benign hydatidiform mole. Follow-up showed a consistent decrease in serum β-HCG levels and no evidence of residual disease. A suspicion of gestational trophoblastic disease should be borne in mind when evaluating a patient with peri- or post-menopausal bleeding to avoid delay in diagnosis and treatment.
基金supported by the National Natural Science Foundation of China (20776089)the New Century Excellent Talent Project of China(NCET-05-0783)
文摘In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.
基金Supported by National Basic Research Program of China (Grant No.2006CB202303)the National Natural Science Foundation of China (Grant No.40672091)
文摘Gas washing has been known in the Tazhong area of the Tarim Basin,but its quantitative assessment has not yet been reported.Here the influence of gas washing fractionation in the area was discussed based on the gas chromatogram data of 68 oils and the results of the mixing experiments of a black oil and a condensate.The results show that the intensity of gas washing fractionation decreased generally from northern to southern part and vertically from deep reservoirs to shallow reservoirs.The gas washing fractionation was mainly controlled by fault systems in this area,with the increase of n-alkane mass depletion positively correlated to the number and scale of faults.Gas washing fractionation appears to have affected the hydrocarbon property,and as a result the diversity of the crude oils is markedly controlled by gas washing.In addition,the occurrence of waxy oil in this area may be resulted from multiple factors including gas washing,mixed filling and migration fractionation.
基金This work was supported by grants from the National Natural Science Foundation of China （No. 81100445）, Talents Project of Beijing Health Bureau （No. 2009-2-11） and the Basic and Clinical Research Cooperation Fund of Capital Medical University （No. 11JL54）.
文摘Twin pregnancy with mosaic partial hydatidiform mole （PHM） and survival of two healthy fetuses following in vitro fertilization and embryos transfer （IVF-ET） is a rare situation and is considered a challenge for management. A 32-year-old Chinese woman conceived twin pregnancy following IVF-ET. At 22 weeks＇ gestation, an additional intrauterine echogenic mass with features of PHM were shown by successive ultrasound examinations. At 35 weeks＇ gestation, two live male infants and two placentas were delivered by caesarean section （CS）. Histologic examination of the abnormal placenta confirmed mosaic PHM. Genetic study showed the abnormal placental mosaicism （expressed in molar-69XXY and normal vili-46XY）, co-existing with a hypospadia new-born （46XY） in one amniotic sac. However, the other one was normal. Serial serum β-hCG levels showed a declining trend and serum β-human chorionic gonadotropin （hCG） were undetectable at 6 months after delivery. The case demonstrated that it is possible to prolonged gestation by PHM under close surveillance during the entire pregnancy.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)Chinese Academy of Sciences Talent Introduction Youth Program(No.SINAP-YCJH-202303)Chinese Academy of Sciences Special Research Assistant Funding Project and Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(JCYJ-SHFY-2021-003)。
文摘A molten salt reactor(MSR)has outstanding features considering the application of thorium fuel,inherent safety,sustainability,and resistance to proliferation.However,fissile material^(233)U is significantly rare at the current stage,thus it is difficult for MSR to achieve a pure thorium-uranium fuel cycle.Therefore,using plutonium or enriched uranium as the initial fuel for MSR is more practical.In this study,we aim to verify the feasibility of a small modular MSR that utilizes plutonium as the starting fuel(SM-MSR-Pu),and highlight its advantages and disadvantages.First,the structural design and fuel management scheme of the SM-MSR-Pu were presented.Second,the neutronic characteristics,such as the graphite-irradiation lifetime,burn-up performance,and coefficient of temperature reactivity were calculated to analyze the physical characteristics of the SM-MSR-Pu.The results indicate that plutonium is a feasible and advantageous starting fuel for a SM-MSR;however,there are certain shortcomings that need to be solved.In a 250 MWth SM-MSR-Pu,approximately 288.64 kg^(233)U of plutonium with a purity of greater than 90% is produced while 978.00 kg is burned every ten years.The temperature reactivity coefficient decreases from -4.0 to -6.5 pcm K^(-1) over the 50-year operating time,which ensures a long-term safe operation.However,the amount of plutonium and accumulation of minor actinides(MAs)would increase as the burn-up time increases,and the annual production and purity of^(233)U will decrease.To achieve an optimal burn-up performance,setting the entire operation time to 30 years is advisable.Regardless,more than 3600 kg of plutonium eventually accumulate in the core.Further research is required to effectively utilize this accumulated plutonium.
文摘Invasive mole is a rare subgroup of gestational trophoblastic disease characterized by the invasion of molar tissue into the myometrium or uterine vasculature. In this paper, we report the third case of invasive mole described in the Malagasy literature. A 33-year-old woman was referred to the Soavinandriana Hospital, her complaint was persistent vaginal bleeding during 2 months, occurring at 3 months of pregnancy with biological anemia without hemodynamic repercussions. The human chorionic gonadotropin (HCG) level was 385,931 mIU/ml. A haemostasis hysterectomy was performed. Histological examination showed an enlarged uterus and endometrial cavity containing edematous chorionic villi with trophoblastic proliferation invading the myometrium. The diagnosis was an invasive mole, stage I, FIGO score 6. Chemotherapy was prescribed but was not honored. After 45 days of follow-up, the serum βHCG level decreased to 1803 mIU/ml, without clinical symptoms. The patient then lost sight. Persistent vaginal bleeding after pregnancy may be the only clinical symptom of an invasive mole and should raise suspicion. Histological examination establishes the diagnosis. As this is an unusual cause of vaginal bleeding, our case should remind physicians that when faced with this symptom, the possibility of an invasive mole should be considered in order to make an early diagnosis for less aggressive treatment.
