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71.
Zhe Chen Jianting Cao Yang Cao Yue Zhang Fanji Gu Guoxian Zhu Zhen Hong Bin Wang Andrzej Cichocki 《Cognitive neurodynamics》2008,2(3):257-271
Electroencephalogram (EEG) is often used in the confirmatory test for brain death diagnosis in clinical practice. Because
EEG recording and monitoring is relatively safe for the patients in deep coma, it is believed to be valuable for either reducing
the risk of brain death diagnosis (while comparing other tests such as the apnea) or preventing mistaken diagnosis. The objective
of this paper is to study several statistical methods for quantitative EEG analysis in order to help bedside or ambulatory
monitoring or diagnosis. We apply signal processing and quantitative statistical analysis for the EEG recordings of 32 adult
patients. For EEG signal processing, independent component analysis (ICA) was applied to separate the independent source components,
followed by Fourier and time-frequency analysis. For quantitative EEG analysis, we apply several statistical complexity measures
to the EEG signals and evaluate the differences between two groups of patients: the subjects in deep coma, and the subjects
who were categorized as brain death. We report statistically significant differences of quantitative statistics with real-life
EEG recordings in such a clinical study, and we also present interpretation and discussions on the preliminary experimental
results.
相似文献
Zhe ChenEmail: |
72.
Yang F Wang H Peng A Liu M Hu P Jiang J 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(20):1789-1794
A sensitive and selective high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of buagafuran in human plasma. The analyte was extracted from plasma samples with hexane after addition of isotopic internal standard and chromatographed on a RP-C(8) column. The mobile phase consisted of methanol-water (90:10, v/v) and the flow rate was 0.2 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reactions monitoring (MRM) mode using positive electrospray ionization (ESI). The method was validated over the concentration range of 0.5-200 ng/mL. Inter- and intra-day precision (RSD%) were all within 15% and the accuracy (RE%) was equal or lower than 9.5%. The lower limit of quantitation (LLOQ) was 0.5 ng/mL. The extraction recovery was on average 38.1% and the detection was not affected by the matrix. The method was successfully applied to the pharmacokinetic study of buagafuran in healthy Chinese volunteers. 相似文献
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75.
光质、光强和光期对水母雪莲愈伤组织生长和黄酮生物合成的影响 总被引:1,自引:0,他引:1
白光、蓝光、红光和远红光等不同光质照射及不同的白光强度对水母雪莲愈伤组织生长、苯丙氨酸氨基裂解酶(PAL) 活性及黄酮合成有不同的影响。红光明显促进愈伤组织的生长,但强烈抑制PAL活性和黄酮的合成。蓝光对愈伤组织生长无明显影响,但显著提高PAL 活性和黄酮的合成。白光的作用介于红光和蓝光之间。远红光的作用与蓝光相似,但作用比较弱。每天16 h 蓝光加8 h 白光和8 h 蓝光加16 h 白光的组合产生最高的黄酮含量和黄酮生产率。 相似文献
76.
Fleishman SJ Whitehead TA Strauch EM Corn JE Qin S Zhou HX Mitchell JC Demerdash ON Takeda-Shitaka M Terashi G Moal IH Li X Bates PA Zacharias M Park H Ko JS Lee H Seok C Bourquard T Bernauer J Poupon A Azé J Soner S Ovali SK Ozbek P Tal NB Haliloglu T Hwang H Vreven T Pierce BG Weng Z Pérez-Cano L Pons C Fernández-Recio J Jiang F Yang F Gong X Cao L Xu X Liu B Wang P Li C Wang C Robert CH Guharoy M Liu S Huang Y Li L Guo D Chen Y Xiao Y London N Itzhaki Z Schueler-Furman O Inbar Y Potapov V 《Journal of molecular biology》2011,414(2):289-302
The CAPRI (Critical Assessment of Predicted Interactions) and CASP (Critical Assessment of protein Structure Prediction) experiments have demonstrated the power of community-wide tests of methodology in assessing the current state of the art and spurring progress in the very challenging areas of protein docking and structure prediction. We sought to bring the power of community-wide experiments to bear on a very challenging protein design problem that provides a complementary but equally fundamental test of current understanding of protein-binding thermodynamics. We have generated a number of designed protein-protein interfaces with very favorable computed binding energies but which do not appear to be formed in experiments, suggesting that there may be important physical chemistry missing in the energy calculations. A total of 28 research groups took up the challenge of determining what is missing: we provided structures of 87 designed complexes and 120 naturally occurring complexes and asked participants to identify energetic contributions and/or structural features that distinguish between the two sets. The community found that electrostatics and solvation terms partially distinguish the designs from the natural complexes, largely due to the nonpolar character of the designed interactions. Beyond this polarity difference, the community found that the designed binding surfaces were, on average, structurally less embedded in the designed monomers, suggesting that backbone conformational rigidity at the designed surface is important for realization of the designed function. These results can be used to improve computational design strategies, but there is still much to be learned; for example, one designed complex, which does form in experiments, was classified by all metrics as a nonbinder. 相似文献
77.
西藏高原冬小麦旗叶光合速率日变化曲线为平坦或单峰型,没有明显“午睡”现象。净光合速率日最高值可与平原接近。光合日总量最高值出现在灌浆中期,其值比平原低4%~34%。净光合速率达20μmolCO2·m-2·s-1以上的环境因子组合是光合有效辐射光量子通量密度2000μmol·m-2·s-1以上,气温25~29℃,近地层大气CO2密度0.41mg·dm-3以上,0cm地温18~23℃、5cm地温15~19℃。这样的因子组合在高原同时满足的机率不高,由于CO2浓度与光温因子高值出现时间不同步,更由于CO2密度比内陆平原低1/3,严重制约了光合日总量值,高原冬小麦旗叶光合作用的特点是净光合速率日最高值可与平原接近,但光合日总量却明显低于平原。 相似文献
78.
Kasi VS Xiao HD Shang LL Iravanian S Langberg J Witham EA Jiao Z Gallego CJ Bernstein KE Dudley SC 《American journal of physiology. Heart and circulatory physiology》2007,293(1):H182-H192
Renin-angiotensin (RAS) system activation is associated with an increased risk of sudden death. Previously, we used cardiac-restricted angiotensin-converting enzyme (ACE) overexpression to construct a mouse model of RAS activation. These ACE 8/8 mice die prematurely and abruptly. Here, we have investigated cardiac electrophysiological abnormalities that may contribute to early mortality in this model. In ACE 8/8 mice, surface ECG voltages are reduced. Intracardiac electrograms showed atrial and ventricular potential amplitudes of 11% and 24% compared with matched wild-type (WT) controls. The atrioventricular (AV), atrio-Hisian (AH), and Hisian-ventricular (HV) intervals were prolonged 2.8-, 2.6-, and 3.9-fold, respectively, in ACE 8/8 vs. WT mice. Various degrees of AV nodal block were present only in ACE 8/8 mice. Intracardiac electrophysiology studies demonstrated that WT and heterozygote (HZ) mice were noninducible, whereas 83% of ACE 8/8 mice demonstrated ventricular tachycardia with burst pacing. Atrial connexin 40 (Cx40) and connexin 43 (Cx43) protein levels, ventricular Cx43 protein level, atrial and ventricular Cx40 mRNA abundances, ventricular Cx43 mRNA abundance, and atrial and ventricular cardiac Na(+) channel (Scn5a) mRNA abundances were reduced in ACE 8/8 compared with WT mice. ACE 8/8 mice demonstrated ventricular Cx43 dephosphorylation. Atrial and ventricular L-type Ca(2+) channel, Kv4.2 K(+) channel alpha-subunit, and Cx45 mRNA abundances and the peak ventricular Na(+) current did not differ between the groups. In isolated heart preparations, a connexin blocker, 1-heptanol (0.5 mM), produced an electrophysiological phenotype similar to that seen in ACE 8/8 mice. Therefore, cardiac-specific ACE overexpression resulted in changes in connexins consistent with the phenotype of low-voltage electrical activity, conduction defects, and induced ventricular arrhythmia. These results may help explain the increased risk of arrhythmia in states of RAS activation such as heart failure. 相似文献
79.
A conserved cysteine motif is critical for rice ceramide kinase activity and function 总被引:1,自引:0,他引:1
Background
Ceramide kinase (CERK) is a key regulator of cell survival in dicotyledonous plants and animals. Much less is known about the roles of CERK and ceramides in mediating cellular processes in monocot plants. Here, we report the characterization of a ceramide kinase, OsCERK, from rice (Oryza sativa spp. Japonica cv. Nipponbare) and investigate the effects of ceramides on rice cell viability.Principal Findings
OsCERK can complement the Arabidopsis CERK mutant acd5. Recombinant OsCERK has ceramide kinase activity with Michaelis-Menten kinetics and optimal activity at 7.0 pH and 40°C. Mg2+ activates OsCERK in a concentration-dependent manner. Importantly, a CXXXCXXC motif, conserved in all ceramide kinases and important for the activity of the human enzyme, is critical for OsCERK enzyme activity and in planta function. In a rice protoplast system, inhibition of CERK leads to cell death and the ratio of added ceramide and ceramide-1-phosphate, CERK''s substrate and product, respectively, influences cell survival. Ceramide-induced rice cell death has apoptotic features and is an active process that requires both de novo protein synthesis and phosphorylation, respectively. Finally, mitochondria membrane potential loss previously associated with ceramide-induced cell death in Arabidopsis was also found in rice, but it occurred with different timing.Conclusions
OsCERK is a bona fide ceramide kinase with a functionally and evolutionarily conserved Cys-rich motif that plays an important role in modulating cell fate in plants. The vital function of the conserved motif in both human and rice CERKs suggests that the biochemical mechanism of CERKs is similar in animals and plants. Furthermore, ceramides induce cell death with similar features in monocot and dicot plants. 相似文献80.
厌氧氨氧化菌(anaerobic ammonia-oxidizing bacteria, AnAOB)的代谢多样性,使得该菌群能够在海洋、湿地和陆地等不同的自然生态系统中广泛分布,甚至在一些极热和极寒环境中也检测到了该菌群的存在。本文回顾并总结了厌氧氨氧化菌在不同生态系统中的发现、分布及脱氮贡献等方面的研究,分析了厌氧氨氧化菌分布的主要环境影响因素。该综述将帮助我们更好地理解全球氮循环中厌氧氨氧化菌的实际角色和功能,并基于厌氧氨氧化(anaerobicammoniaoxidation,anammox)过程,探究能与其进行协作的新型生物脱氮工艺,以期为这些工艺的研发和推广提供生态学基础和新的思考,从而实现脱氮工艺的技术变革。 相似文献