半导体技术快速发展,双倍数据速率同步动态随机存取存储器(Double Data Rata Synchronous Dynamic Random Access Memory,DDR SDRAM)的信号完整性问题已成为设计难点。文中提出了一种基于ANSYS软件和IBIS 5.0模型的DDR4 SDRAM信号完整...半导体技术快速发展,双倍数据速率同步动态随机存取存储器(Double Data Rata Synchronous Dynamic Random Access Memory,DDR SDRAM)的信号完整性问题已成为设计难点。文中提出了一种基于ANSYS软件和IBIS 5.0模型的DDR4 SDRAM信号完整性仿真方法。利用IBIS 5.0模型中增加的复合电流(Composite Current)、同步开关输出电流等数据,对DDR4 SDRAM高速电路板的信号完整性进行更准确的仿真分析。仿真结果表明:高速信号在经过印制板走线和器件封装后,信号摆幅和眼图都有明显恶化;在仿真电路的电源上增加去耦电容后,信号抖动和收发端同步开关噪声(Synchronous Switching Noise,SSN)都得到明显改善;在不加去耦电容的情况下,将输入信号由PRBS码换成DBI信号,接收端的同步开关噪声有所改善,器件功耗可以降为原来的一半。展开更多
The vacuolar proton pump ATPase（V-H^＋-ATPase）, which is a multi-subunit membrane protein complex, plays a major role in the activation of ion and nutrient transport and has been suggested to be involved in several ...The vacuolar proton pump ATPase（V-H^＋-ATPase）, which is a multi-subunit membrane protein complex, plays a major role in the activation of ion and nutrient transport and has been suggested to be involved in several physiological processes, such as cell expansion and salt tolerance. In this study, three genes encoding V-H^＋-ATPase subunits B（Sc VHA-B, Gen Bank： JF826506）, C（Sc VHA-C, Gen Bank： JF826507） and H（Sc VHA-H, Gen Bank： JF826508） were isolated from the halophyte Suaeda corniculata. The transcript levels of Sc VHA-B, Sc VHA-C and Sc VHA-H were increased by salt, drought and saline-alkali treatments. V-H^＋-ATPase activity was also examined under salt, drought and saline-alkali stresses. The results showed that V-H^＋-ATPase activity was correlated with salt, drought and saline-alkali stress. Furthermore, V-H^＋-ATPase subunits B, C and H（Sc VHA-B, Sc VHA-C and Sc VHA-H） from S. corniculata were introduced separately into the alfalfa genome. The transgenic alfalfa was verified by Southern and Northern blot analysis. During salt and saline-alkali stresses, transgenic lines carrying the B, C and H subunits had higher germination rates than the wild type（WT）. More free proline, higher superoxide dismutase（SOD） activity and lower malondialdehyde（MDA） levels were detected in the transgenic plants under salt and saline-alkali treatments. Moreover, the Sc VHA-B transgenic lines showed greater tolerance to salt and saline-alkali stresses than the WT. These results suggest that overexpression of Sc VHA-B, Sc VHA-C and Sc VHA-H improves tolerance to salt and saline-alkali stresses in transgenic alfalfa.展开更多
Background Intracranial infection is a common postoperative complication of neurosurgery. This study aimed to identify risk factors of postoperative intracranial infection in patients with cerebrospinal fluid rhinorrh...Background Intracranial infection is a common postoperative complication of neurosurgery. This study aimed to identify risk factors of postoperative intracranial infection in patients with cerebrospinal fluid rhinorrhea and to suggest proposals for the prevention. Methods A total of 167 patients （113 males and 54 males, average age of 34.4 years） with cerebrospinal fluid rhinorrhea operated on by the senior author were retrospectively reviewed. The data collected included etiology, previous history, clinical manifestation, site of bone defect, operative approach, and postoperative complications. Risk factor（s） for postoperative infection were analyzed using the stepwise multiple Logistic regression. Results Eighteen （10.8%） patients were infected post-operatively. The independent risk factors for infection were the site of defect （RR=0.508, 95% Cl 0.306-0.843, P=0.009） and historical meningitis （RR=0.290, 95% Cl 0.094-0.893, P=0.031）. Patients with multiple defects and saddle floor defects had a higher infection rate. The germiculture was positive in 11 patients, and vancomycin was sensitive to all the pathogenesis. Nine infected patients needed lumbar drainage. Ten patients had hyponatremia, and hydrocephalus occurred in two patients with serious trauma. Conclusions To prevent the infection, we should pay closer attention to the high-risk patients pre-operation. During the operation, the methods those can improve wound healing, such as using blood-supply materials, reliable fixation, and eliminating dead space are all helpful. Conducting lumbar drainage and choosing effective prophylactic antibiotics in the early postoperative stage for the high-risk patients are methods of postoperative management.展开更多
Background Carbon dioxide （CO2） laser soldering is an alternative technique for tissue bonding.Basic fibroblast growth factor （bFGF） and transforming growth factor β1 （TGFβ1） are two key factors for wound heal...Background Carbon dioxide （CO2） laser soldering is an alternative technique for tissue bonding.Basic fibroblast growth factor （bFGF） and transforming growth factor β1 （TGFβ1） are two key factors for wound healing.This study was performed to demonstrate the efficacy of CO2 laser soldering for dural reconstruction and the effect of bFGF and TGFβ1 on healing.Methods In Part Ⅰ,10 minipigs were randomized into two equal groups.Dural defects were reconstructed by conventional fibrin glue bonding （group Ⅰa） or CO2 laser soldering （group Ⅰb）.The reconstructed dura was subjected to burst pressure （BP） measurement and immunohistochemical staining after 1 week.In Part Ⅱ,36 minipigs were randomized into three equal groups.Dural reconstruction was achieved by CO2 laser soldering.Exogenous bFGF （group Ⅱb） or TGFβ1 （group Ⅱc） was administered while group Ⅱa served as a control group.The specimens were subjected to BP measurement after 1,2,3,and 4 weeks,respectively.Results In Part Ⅰ,the dura specimens displayed positive staining of only bFGF in group la and of both bFGF and TGFβ1 in group lb.Group Ⅰb showed higher BP than group la （（98.00-±21.41） mmHg vs.（70.80±15.09） mmHg,respectively; P 〈0.05）.In Part Ⅱ,BP of group Ⅱc was significantly higher than that of group Ⅱla （P 〈0.01）.The BP of group Ⅱa trended toward stabilization after 3 weeks of growth,while that of groups lⅡb and Ⅱc trended toward stabilization after 2 weeks of growth.Conclusions CO2 laser soldering is a reliable technique for dural reconstruction.The superior healing of dural reconstruction by CO2 laser soldering may be related to higher expression of bFGF and TGFβ1,and CO2 lasers may stimulate their secretion.Exogenous bFGF or TGFβ1 may improve healing by shortening the wound healing time,and exogenous TGFβ1 may improve the tensile strength.展开更多
基金supported by the National Natural Science Foundation of China (31271746, 31401403, 31501366,31201237)
文摘The vacuolar proton pump ATPase（V-H^＋-ATPase）, which is a multi-subunit membrane protein complex, plays a major role in the activation of ion and nutrient transport and has been suggested to be involved in several physiological processes, such as cell expansion and salt tolerance. In this study, three genes encoding V-H^＋-ATPase subunits B（Sc VHA-B, Gen Bank： JF826506）, C（Sc VHA-C, Gen Bank： JF826507） and H（Sc VHA-H, Gen Bank： JF826508） were isolated from the halophyte Suaeda corniculata. The transcript levels of Sc VHA-B, Sc VHA-C and Sc VHA-H were increased by salt, drought and saline-alkali treatments. V-H^＋-ATPase activity was also examined under salt, drought and saline-alkali stresses. The results showed that V-H^＋-ATPase activity was correlated with salt, drought and saline-alkali stress. Furthermore, V-H^＋-ATPase subunits B, C and H（Sc VHA-B, Sc VHA-C and Sc VHA-H） from S. corniculata were introduced separately into the alfalfa genome. The transgenic alfalfa was verified by Southern and Northern blot analysis. During salt and saline-alkali stresses, transgenic lines carrying the B, C and H subunits had higher germination rates than the wild type（WT）. More free proline, higher superoxide dismutase（SOD） activity and lower malondialdehyde（MDA） levels were detected in the transgenic plants under salt and saline-alkali treatments. Moreover, the Sc VHA-B transgenic lines showed greater tolerance to salt and saline-alkali stresses than the WT. These results suggest that overexpression of Sc VHA-B, Sc VHA-C and Sc VHA-H improves tolerance to salt and saline-alkali stresses in transgenic alfalfa.
文摘Background Intracranial infection is a common postoperative complication of neurosurgery. This study aimed to identify risk factors of postoperative intracranial infection in patients with cerebrospinal fluid rhinorrhea and to suggest proposals for the prevention. Methods A total of 167 patients （113 males and 54 males, average age of 34.4 years） with cerebrospinal fluid rhinorrhea operated on by the senior author were retrospectively reviewed. The data collected included etiology, previous history, clinical manifestation, site of bone defect, operative approach, and postoperative complications. Risk factor（s） for postoperative infection were analyzed using the stepwise multiple Logistic regression. Results Eighteen （10.8%） patients were infected post-operatively. The independent risk factors for infection were the site of defect （RR=0.508, 95% Cl 0.306-0.843, P=0.009） and historical meningitis （RR=0.290, 95% Cl 0.094-0.893, P=0.031）. Patients with multiple defects and saddle floor defects had a higher infection rate. The germiculture was positive in 11 patients, and vancomycin was sensitive to all the pathogenesis. Nine infected patients needed lumbar drainage. Ten patients had hyponatremia, and hydrocephalus occurred in two patients with serious trauma. Conclusions To prevent the infection, we should pay closer attention to the high-risk patients pre-operation. During the operation, the methods those can improve wound healing, such as using blood-supply materials, reliable fixation, and eliminating dead space are all helpful. Conducting lumbar drainage and choosing effective prophylactic antibiotics in the early postoperative stage for the high-risk patients are methods of postoperative management.
基金This research project was supported by grants from the National Natural Science Foundation of China （No.30870752） and Beijing Natural Science Foundation （No.3092012）.
文摘Background Carbon dioxide （CO2） laser soldering is an alternative technique for tissue bonding.Basic fibroblast growth factor （bFGF） and transforming growth factor β1 （TGFβ1） are two key factors for wound healing.This study was performed to demonstrate the efficacy of CO2 laser soldering for dural reconstruction and the effect of bFGF and TGFβ1 on healing.Methods In Part Ⅰ,10 minipigs were randomized into two equal groups.Dural defects were reconstructed by conventional fibrin glue bonding （group Ⅰa） or CO2 laser soldering （group Ⅰb）.The reconstructed dura was subjected to burst pressure （BP） measurement and immunohistochemical staining after 1 week.In Part Ⅱ,36 minipigs were randomized into three equal groups.Dural reconstruction was achieved by CO2 laser soldering.Exogenous bFGF （group Ⅱb） or TGFβ1 （group Ⅱc） was administered while group Ⅱa served as a control group.The specimens were subjected to BP measurement after 1,2,3,and 4 weeks,respectively.Results In Part Ⅰ,the dura specimens displayed positive staining of only bFGF in group la and of both bFGF and TGFβ1 in group lb.Group Ⅰb showed higher BP than group la （（98.00-±21.41） mmHg vs.（70.80±15.09） mmHg,respectively; P 〈0.05）.In Part Ⅱ,BP of group Ⅱc was significantly higher than that of group Ⅱla （P 〈0.01）.The BP of group Ⅱa trended toward stabilization after 3 weeks of growth,while that of groups lⅡb and Ⅱc trended toward stabilization after 2 weeks of growth.Conclusions CO2 laser soldering is a reliable technique for dural reconstruction.The superior healing of dural reconstruction by CO2 laser soldering may be related to higher expression of bFGF and TGFβ1,and CO2 lasers may stimulate their secretion.Exogenous bFGF or TGFβ1 may improve healing by shortening the wound healing time,and exogenous TGFβ1 may improve the tensile strength.
