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951.
螺旋CT三维重建技术在胫骨平台骨折的诊疗应用分析 总被引:1,自引:0,他引:1
目的探讨螺旋CT三维重建在胫骨平台骨折中的临床应用。方法回顾性分析2007-2008年55例胫骨平台骨折病例.手术前均常规行X线摄片,行螺旋CT三维重建并与术中所见对照。结果所有病例螺旋CT三维重建明确地显示了骨折,并在骨折的分型和关节面碎裂情况的描述上较平片优越,与手术中所见一致。结论CT多种成像后处理技术可清晰显示骨折的部位、骨折线的走行方向、骨质碎裂程度和移位的距离以及关节面塌陷情况等,对术前分型、制订手术治疗方案具有重要的参考价值。 相似文献
952.
Jiangong Liu Yulun Zhou Alex Valach Robert Shortt Kuno Kasak Camilo Rey‐Sanchez Kyle S. Hemes Dennis Baldocchi Derrick Y. F. Lai 《Global Change Biology》2020,26(9):4998-5016
The role of coastal mangrove wetlands in sequestering atmospheric carbon dioxide (CO2) and mitigating climate change has received increasing attention in recent years. While recent studies have shown that methane (CH4) emissions can potentially offset the carbon burial rates in low‐salinity coastal wetlands, there is hitherto a paucity of direct and year‐round measurements of ecosystem‐scale CH4 flux (FCH4) from mangrove ecosystems. In this study, we examined the temporal variations and biophysical drivers of ecosystem‐scale FCH4 in a subtropical estuarine mangrove wetland based on 3 years of eddy covariance measurements. Our results showed that daily mangrove FCH4 reached a peak of over 0.1 g CH4‐C m?2 day?1 during the summertime owing to a combination of high temperature and low salinity, while the wintertime FCH4 was negligible. In this mangrove, the mean annual CH4 emission was 11.7 ± 0.4 g CH4‐C m–2 year?1 while the annual net ecosystem CO2 exchange ranged between ?891 and ?690 g CO2‐C m?2 year?1, indicating a net cooling effect on climate over decadal to centurial timescales. Meanwhile, we showed that mangrove FCH4 could offset the negative radiative forcing caused by CO2 uptake by 52% and 24% over a time horizon of 20 and 100 years, respectively, based on the corresponding sustained‐flux global warming potentials. Moreover, we found that 87% and 69% of the total variance of daily FCH4 could be explained by the random forest machine learning algorithm and traditional linear regression model, respectively, with soil temperature and salinity being the most dominant controls. This study was the first of its kind to characterize ecosystem‐scale FCH4 in a mangrove wetland with long‐term eddy covariance measurements. Our findings implied that future environmental changes such as climate warming and increasing river discharge might increase CH4 emissions and hence reduce the net radiative cooling effect of estuarine mangrove forests. 相似文献
953.
The objective of this study was to investigate the difference in electrophoretic mobility between partially and fully poly(ethylene glycol)-conjugated poly(amidoamine) dendrimers (part-PEG-PAMAM and full-PEG-PAMAM, respectively) using a microchip capillary gel electrophoresis (MCGE). While MCGE allowed size-based separation of PEG-PAMAMs prepared with monomethoxy PEG-nitrophenyl carbonate, full-PEG-PAMAMs migrated slower than part-PEG-PAMAMs that were similar in size or larger. When the measured molecular weights obtained from MCGE analysis and the calculated molecular weights were plotted, each part-PEG-PAMAM and full-PEG-PAMAM showed correlation coefficients greater than 0.98. This study indicates that MCGE would be useful for characterizing PEG-PAMAMs with different PEGylation degrees. 相似文献
954.
Quercetin and other flavonoids have been reported to exhibit both antioxidant and pro‐oxidant properties. Most studies about the pro‐oxidative ability were conducted in the presence of metal ions, and the essential functional moiety of quercetin responsible for the pro‐oxidative effect is still unclear. In this study, we evaluated the pro‐oxidative abilities in the absence of metal ions of two quercetin derivatives, i.e., quercetin‐3′‐O‐β‐D ‐glucoside ( 1 ) and quercetin‐3‐O‐β‐D ‐glucoside ( 2 ), by assessing DNA cleavage and HO.‐radical production. The binding mode between these compounds and DNA was studied by fluorescence and viscometric titrations. The results showed that 1 can efficiently induce oxidative damage to plasmid DNA, while 2 shows poor activity. Both 1 and 2 bind to DNA via groove‐binding. These results proved that the α‐hydroxy‐β‐oxo‐α,β‐enone moiety contributes to the pro‐oxidative activity of quercetin. 相似文献
955.
Jiao Zhan Xi Zhu Wei Zhou Hui Chen Chenliu He Qiang Wang 《Molecular microbiology》2016,102(4):738-751
Thylakoid formation1 protein (Thf1) is a multifunctional protein that is conserved in all photosynthetic organisms. In this study, we used the model cyanobacterium Synechococcus sp. PCC7942 (hereafter Synechococcus) to show that the level of Thf1 is altered in response to various stress conditions. Although this protein has been reported to be involved in thylakoid formation, the thylakoid membrane in the thf1 deletion strain (ΔThf1) was not affected. Compared with the WT, ΔThf1 showed reduced PS II activity, with increased levels of D1 under high light (HL) conditions, which was resulted from blocked D1 degradation by the FtsH protease and thus inhibits PS II repair. PS I was found to be more seriously affected than PS II in ΔThf1, even under low light conditions, suggesting that PS I damage could be the primary effect of thf1 deletion in Synechococcus. Further analysis revealed that the ΔThf1 mutant had a lower PS I subunit content and lower PS I stability under HL conditions. Further sucrose gradient fractionation of the membrane protein complexes and crosslinking and immunoblot analysis indicated that Thf1 interacts with PS I. Together, our results reveal that Thf1 interacts with PS I and thereby stabilizes PS I in Synechococcus. 相似文献
956.
957.
Hong-Jin Zhao Yan Li De-Yu Wang Hai-Tao Yuan 《Journal of cellular and molecular medicine》2021,25(23):11031-11034
The administration of ACEI/ARB (angiotensin-converting enzyme inhibitors/Angiotension II receptor blockers) in COVID-19 (coronavirus disease 2019) patients with hypertension exhibits a lower risk of mortality compared with ACEI/ARB non-users. In this context, an important question arises: is ACEI or ARB more suitable for the treatment of hypertensive COVID-19 patients? Taken into consideration the following four rationales, ARB may offer a more significant benefit than ACEI for the short-term treatment of hypertensive COVID-19 patients: 1. ACEI has no inhibition on non-ACE-mediated Ang II production under infection conditions, whereas ARB can function properly regardless of how Ang II is produced; 2. ACEI-induced bradykinin accumulation may instigate severe ARDS while ARB has no effects on kinin metabolism; 3. ARB alleviates viscous sputa production and inflammatory reaction significantly in contrast to ACEI; 4. ARB may attenuate the lung fibrosis induced by mechanical ventilation in severe patients and improve their prognosis significantly compared with ACEI. To examine the advantages of ARB over ACEI on hypertensive COVID-19 patients, retrospective case-control studies comparing the clinical outcomes for COVID-19 patients receiving ARB or ACEI treatment is strikingly needed in order to provide guidance for the clinical application. 相似文献
958.
Meng Sun Jing Ren Hui Du Yanmin Zhang Jie Zhang Sicen Wang Langchong He 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(28):2712-2718
We have developed an online analytical method that combines A431 cell membrane chromatography (A431/CMC) with high performance liquid chromatography and mass spectrometry (LC/MS) for identifying active components from Radix Caulophylli acting on human EGFR. Retention fractions on A431/CMC model were captured onto an enrichment column and the components were directly analyzed by combining a 10-port column switcher with an LC/MS system for separation and preliminary identification. Using Sorafenib tosylate as a positive control, taspine and caulophine from Radix Caulophylli were identified as the active molecules which could act on the EGFR. This A431/CMC-online-LC/MS method can be applied for screening active components acting on EGFR from traditional Chinese medicines exemplified by Radix Caulophylli and will be of great utility in drug discovery using natural medicinal herbs as a source of novel compounds. 相似文献
959.
银杏叶提取物对糖尿病大鼠心肌损伤的防护作用 总被引:9,自引:0,他引:9
目的:研究银杏叶提取物(EGb)对糖尿病大鼠心肌的防护作用.方法:用光镜和透射电镜观察EGb对糖尿病大鼠心肌的形态学改变,并测定心肌组织内超氧化物歧化酶(SOD)、一氧化氮合酶(NOS)、结构型一氧化氮合酶(cNOS)、诱导型一氧化氮合酶(iNOS)的活性及一氧化氮(NO)、丙二醛(MDA)的含量.结果:糖尿病大鼠心肌光镜下主要表现为心肌细胞空泡变性及心肌纤维局灶性溶解;电镜下主要表现为心肌线粒体肿胀,嵴变短,肌原纤维溶解;SOD活性下降,NOS、iNOS活性及MDA、NO含量增高.EGb治疗组病变明显减轻,EGb治疗组心肌组织内SOD活性明显高于糖尿病组,NOS、iNOS活性及MDA、NO含量低于糖尿病组.结论:EGb可能通过抗脂质过氧化作用和降低NO水平而对糖尿病心肌产生保护作用. 相似文献
960.
Yan-Ru Cao Yi Jiang Qian Wang Shu-Kun Tang Wen-Xiang He Quan-Hong Xue Li-Hua Xu Cheng-Lin Jiang 《Antonie van Leeuwenhoek》2010,98(3):389-394
A novel pink-coloured, non-spore-forming, non-motile, Gram-negative bacterium, designated YIM 48858T, is described by using a polyphasic approach. The strain can grow at pH 6.5–9 (optimum at pH 7) and 25–30°C (optimum at 28°C).
NaCl is not required for its growth. Positive for oxidase and catalase. Urease activity, nitrate reduction, starch and Tween
80 tests are negative reaction. 16S rRNA gene sequence similarity studies showed that strain YIM 48858T is a member of the genus Rubellimicrobium, with similarities of 96.3, 95.7 and 95.5% to Rubellimicrobium mesophilum MSL-20T, Rubellimicrobium aerolatum 5715S-9T and Rubellimicrobium
thermophilum DSM 16684T, respectively. Q-10 was the predominant respiratory ubiquinone as in the other members of the genus Rubellimicrobium. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphoglycolipid, glycolipid and the major fatty
acids were C18:1 ω7c, C16:0 and C10:0 3-OH, which are very different from the valid published species. The DNA G + C content
was 67.7 mol%. Both phylogenetic and chemotaxonomic evidence supports that YIM 48858T is a novel species of the genus Rubellimicrobium, for which the name Rubellimicrobium roseum sp. nov. is proposed. The type strain is YIM 48858T (=CCTCC AA 208029T =KCTC 23202T). 相似文献