排序方式: 共有269条查询结果,搜索用时 31 毫秒
21.
Nima Dehghani Claude Bédard Sydney S. Cash Eric Halgren Alain Destexhe 《Journal of computational neuroscience》2010,29(3):405-421
The resistive or non-resistive nature of the extracellular space in the brain is still debated, and is an important issue
for correctly modeling extracellular potentials. Here, we first show theoretically that if the medium is resistive, the frequency
scaling should be the same for electroencephalogram (EEG) and magnetoencephalogram (MEG) signals at low frequencies (<10 Hz).
To test this prediction, we analyzed the spectrum of simultaneous EEG and MEG measurements in four human subjects. The frequency
scaling of EEG displays coherent variations across the brain, in general between 1/f and 1/f
2, and tends to be smaller in parietal/temporal regions. In a given region, although the variability of the frequency scaling
exponent was higher for MEG compared to EEG, both signals consistently scale with a different exponent. In some cases, the
scaling was similar, but only when the signal-to-noise ratio of the MEG was low. Several methods of noise correction for environmental
and instrumental noise were tested, and they all increased the difference between EEG and MEG scaling. In conclusion, there
is a significant difference in frequency scaling between EEG and MEG, which can be explained if the extracellular medium (including
other layers such as dura matter and skull) is globally non-resistive. 相似文献
22.
To date, the majority of plant small RNAs (sRNA) have been identified in rice, poplar and Arabidopsis. To identify novel tomato sRNAs potentially involved in tomato specific processes such as fruit development and/or ripening,
we cloned 4,018 sRNAs from tomato fruit tissue at the mature green stage. From this pool of sRNAs, we detected tomato homologues
of nine known miRNAs, including miR482; a poplar miRNA not conserved in Arabidopsis or rice. We identified three novel putative miRNAs with flanking sequence that could be folded into a stem-loop precursor
structure and which accumulated as 19-24nt RNA. One of these putative miRNAs (Put-miRNA3) exhibited significantly higher expression
in fruit compared with leaf tissues, indicating a specific role in fruit development processes. We also identified nine sRNAs
that accumulated as 19–24nt RNA species in tomato but genome sequence was not available for these loci. None of the nine sRNAs
or three putative miRNAs possessed a homologue in Arabidopsis that had a precursor with a predicted stem-loop structure or that accumulated as a sRNA species, suggesting that the 12 sRNAs
we have identified in tomato may have a species specific role in this model fruit species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
23.
北京黑猪FSHb 亚基基因的多态性与繁殖性状的关联分析 总被引:9,自引:0,他引:9
本研究以北京黑猪为研究对象, 以FSHb 亚基基因为产仔性状的候选基因, 分别采用PCR产物直接电泳和PCR-RFLP方法来检测FSHβ亚基基因2个位点的多态性。结合测序发现: FSHb-1位点上, 北京黑猪BB型的134与135 bp (D00621序列的6 473与6 474 bp) 之间插入273 bp的片段而产生多态, 序列分析表明该插入片段为一典型的逆转座子, 在插入片段中还发现了一个RNA 聚合酶Ⅲ内部启动子; FSHb-2位点上, 由于扩增片段173 bp处存在C→T的突变, 使得HaeⅢ酶切位点消失而产生多态; 2个位点的A、B等位基因在北京黑猪群体中都有分布, 且处于低度多态。χ2适合性检验结果表明, 该群体在这2个位点的突变都达到Hardy-Weinberg平衡状态 (P>0.05)。用SAS 8.2 软件最小二乘法拟合线性模型, 将基因座不同基因型与繁殖性状总产仔数 (TNB)、产活仔数 (NBA) 和出生重 (WB) 进行了关联分析, 结果表明: 就初产母猪而言, FSHb-1位点上, AA型比AB和BB型个体的TNB分别多0.96头和1.85头 (P<0.05), AA和AB型比BB型个体的NBA分别多0.95头和1.69头(P<0.05)。FSHb-2位点上, AA型比AB型和BB型个体的TNB分别多1.57头和2.15头 (P<0.05); AA和AB型比BB型个体的NBA分别多1.00头和0.94头 (P<0.05); 就经产母猪而言, FSHb-2位点上, AA型个体的WB比BB型的WB重0.25 kg (P<0.05)。全部群体的FSHb-1位点的A等位基因和初产母猪FSHb-2位点的A等位基因对TNB、NBA和WB表现为正效应。 相似文献
24.
Yu Zhao Mona C Majid Jennifer M Soll Joshua R Brickner Sebastian Dango Nima Mosammaparast 《The EMBO journal》2015,34(12):1687-1703
Repair of DNA alkylation damage is critical for genomic stability and involves multiple conserved enzymatic pathways. Alkylation damage resistance, which is critical in cancer chemotherapy, depends on the overexpression of alkylation repair proteins. However, the mechanisms responsible for this upregulation are unknown. Here, we show that an OTU domain deubiquitinase, OTUD4, is a positive regulator of ALKBH2 and ALKBH3, two DNA demethylases critical for alkylation repair. Remarkably, we find that OTUD4 catalytic activity is completely dispensable for this function. Rather, OTUD4 is a scaffold for USP7 and USP9X, two deubiquitinases that act directly on the AlkB proteins. Moreover, we show that loss of OTUD4, USP7, or USP9X in tumor cells makes them significantly more sensitive to alkylating agents. Taken together, this work reveals a novel, noncanonical mechanism by which an OTU family deubiquitinase regulates its substrates, and provides multiple new targets for alkylation chemotherapy sensitization of tumors. 相似文献
25.
First Report of Curtobacterium flaccumfaciens pv. flaccumfaciens Causing Cowpea Bacterial Wilt in Iran 下载免费PDF全文
Ebrahim Osdaghi Babak Pakdaman Sardrood Majed Bavi Nima Akbari Oghaz Shabnam Kimiaei Saideh Hadian 《Journal of Phytopathology》2015,163(7-8):653-656
During surveys in cowpea fields of Marand County, East Azerbaijan province, Iran, in the summer of 2013, a suspected bacterial disease was observed on cowpea leaves as tan spots and interveinal necrotic lesions surrounded by chlorotic margins. The disease was of high incidence where some fields had been fully destroyed and severity of the disease in some fields had reached up to 70%. Gram‐positive, yellow‐pigmented, coryneform bacteria were isolated from infected leaves. Pathogenicity of isolates was confirmed on 20‐day‐old cowpea (cv. Khoy) plants, and they were identified as Curtobacterium flaccumfaciens pv. flaccumfaciens based on biochemical test results confirmed using specific PCR primers. This is the first report of C. flaccumfaciens pv. flaccumfaciens, the causal agent of cowpea bacterial wilt in Iran. 相似文献
26.
Mohammed Arifullah Chiruvella Kishore K. Namsa Nima D. Ghanta Rama Gopal 《Physiology and Molecular Biology of Plants》2015,21(3):417-424
Physiology and Molecular Biology of Plants - Bixa orellana L. (Bixaceae) is a multipurpose tree grown for the production of commercially important dyes. In the present study, an efficient,... 相似文献
27.
Nima Taha Jing Zhang Reza Rafie Rupesh Ranjan Salima Qamruddin Tasneem Z Naqvi 《Cardiovascular ultrasound》2011,9(1):1-12
Background
Biventricular (Biv) pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP) assessment by radial artery tonometry in guiding Biv pacemaker optimization.Methods
Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV) ejection fraction (EF) 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI), ejection time (ET), myocardial performance index (MPI), radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated.Results
Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p < 0.001), LV VTI (15.9 ± 4.8 cm to 18.4 ± 5.1 cm, p < 0.001) and MPI (0.57 ± 0.2 to 0.45 ± 0.13, p < 0.001) and in PEP (246.7 ± 36.1 ms to 234.7 ± 35.5 ms, p = 0.003), PEP/ET (0.88 ± 0.21 to 0.79 ± 0.17, p < 0.001), and PEP/VTI (17.3 ± 7 to 13.78 ± 4.7, p < 0.001). The correlation between comprehensive echo Doppler and radial artery tonometry-PEP guided optimal atrioventricular delay (AVD) and optimal interventricular delay (VVD) was 0.75 (p < 0.001) and 0.69 (p < 0.001) respectively. In 29 patients with follow up assessment, New York Heart Association (NYHA) class reduced from 2.5 ± 0.8 to 2.0 ± 0.9 (p = 0.004) at 1.8 ± 1.4 months.Conclusion
An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization. 相似文献28.
29.
Mamishi S Ahmadi F Ahmadi M Rezaei N 《Acta microbiologica et immunologica Hungarica》2011,58(4):297-301
Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disease, affecting phagocytic blood cells, which predispose patients to recurrent infectious complications. Herein, an 11-year-old girl is described who presented with liver abscess at the age of 9 years. Positive dihydrorhodamine (DHR) and nitrobluetetrazolium (NBT) tests confirmed the diagnosis of CGD for the patient. Anti-tuberculosis drugs and parenteral antibiotic therapy were started. Unusual visceral abscess and recurrent infections should be considered as an alarm for primary immunodeficiency diseases, while early diagnosis and appropriate treatment could prevent severe complications and even death in this group of patients. 相似文献
30.
IL-12Rβ1 deficiency in two of fifty children with severe tuberculosis from Iran, Morocco, and Turkey
Boisson-Dupuis S El Baghdadi J Parvaneh N Bousfiha A Bustamante J Feinberg J Samarina A Grant AV Janniere L El Hafidi N Hassani A Nolan D Najib J Camcioglu Y Hatipoglu N Aydogmus C Tanir G Aytekin C Keser M Somer A Aksu G Kutukculer N Mansouri D Mahdaviani A Mamishi S Alcais A Abel L Casanova JL 《PloS one》2011,6(4):e18524