Herein, a dual microRNA (miRNA) powered bi-directional DNA walking machine with precise control was developed to fabricate an enzyme-free biosensor on the basis of distance-based ...electrochemiluminescence (ECL) energy transfer for multiple detection of miRNAs. By using miRNA-21 as the driving force, the DNA walker could move forth along the track and generated quenching of ECL response due to the proximity between Au nanoparticles (AuNPs) and Mn2+ doped CdS nanocrystals (CdS:Mn NCs) film as the ECL emitters, realizing ultrasensitive determination of miRNA-21. Impressively, once miRNA-155 was introduced as the driving force, the walker could move back along the track automatically, and surface plasmon resonance (SPR) occurred owing to the appropriate large separation between AuNPs and CdS:Mn NCs, achieving an ECL enhancement and realizing ultrasensitive detection of miRNA-155. The bi-directional movement of the DNA walker on the track led to continuous distance-based energy transfer from CdS:Mn NCs film by AuNPs, which resulted in significant ECL signal variation of CdS:Mn NCs for multiple detection of miRNA-21 and miRNA-155 down to 1.51 fM and 1.67 fM, respectively. Amazingly, the elaborated biosensor provided a new chance for constructing controllable molecular nanomachines in biosensing, disease diagnosis, and clinical analysis.
A set of improved and efficient radiation parameterization schemes for surface radiation balance components under clear- sky conditions was developed by using general surface measurements and MODIS ...data. The set of schemes was then adapted for regions similar to the present study sites under different grazing intensities and varying degrees of drought in the semiarid grasslands of Inner Mongolia. Specifically, we mainly improved two schemes for estimating downward shortwave and longwave radiation at the surface, which could be applied to regions with certain degrees of drought. The validation datasets were from ground-based observations at various grazing sites during the growing season （May to September） of different drought years, 2005 and 2006. Through comparisons of parameterized versus measured radiation values, the increased or modified factors in the original schemes demonstrated improved estimation accuracy, and the rationalities of input parameters and variables were analyzed. The regional instantaneous net radiation estimations had root-mean-square errors of less than 30 W m-2 compared with ground measurements at the sites during the study period. The statistical results showed the improved schemes are suitable for estimating surface net radiation in regional semiarid areas during the growing season. Analyses of the sensitivity of the schemes to corresponding variables were conducted to ascertain the major error sources of the schemes and potential variables for improving the performance of the schemes in agreement with observations.
Reversing the switching of DNA scissors with precisely control remains a compelling goal. Herein, based on strand displacement reaction within single step, the DNA scissor realized reversible ...switching and further controlled the distance of end strands along the movement of DNA scissor, which has been applied for the development of a regenerated sensing platform for the ultrasensitive detection of microRNA-21 (miRNA-21) with the electrochemiluminescence (ECL) complex (PEI-Ru(II)) as luminophores and diethylenetriamine (DETA) as the coreactant. In the presence of ferrocene-labeled DNA (Fc-DNA), the DETA-labeled DNA scissor clockwise switched to “off” state based on strand displacement reaction, resulting in the significant ECL quenching of Ru(II) system. Next, by using miRNA-21 as the motive fuel, the configuration of DNA scissor could be anticlockwise switched, which significantly enhanced the ECL intensity of Ru(II) complex due to the releasing of Fc-DNA and the proximity between DETA and Ru(II) complex. The reversible switching of DNA scissor led to the remarkably enhancing of ECL signal, realizing ultrasensitive detection of miRNA-21 with an excellent detection limit of 0.17 fM, which was also applied in miRNA detection successfully from different cancer cells. Impressively, the reversible switching of DNA scissor biosensor was able to realize the regeneration of the biosensing platform by adding an additional single stranded DNA (ssDNA) based on strand displacement reaction within a single step, providing a novel concept for constructing simple and sensitive regenerated biosensor.
Herein, we describe the pharmacokinetic optimization of a series of class-selective histone deacetylase (HDAC) inhibitors and the subsequent identification of candidate predictive biomarkers of ...hepatocellular carcinoma (HCC) tumor response for our clinical lead using patient-derived HCC tumor xenograft models. Through a combination of conformational constraint and scaffold hopping, we lowered the in vivo clearance (CL) and significantly improved the bioavailability (F) and exposure (AUC) of our HDAC inhibitors while maintaining selectivity toward the class I HDAC family with particular potency against HDAC1, resulting in clinical lead 5 (HDAC1 IC50 = 60 nM, mouse CL = 39 mL/min/kg, mouse F = 100%, mouse AUC after single oral dose at 10 mg/kg = 6316 h·ng/mL). We then evaluated 5 in a biomarker discovery pilot study using patient-derived tumor xenograft models, wherein two out of the three models responded to treatment. By comparing tumor response status to compound tumor exposure, induction of acetylated histone H3, candidate gene expression changes, and promoter DNA methylation status from all three models at various time points, we identified preliminary candidate response prediction biomarkers that warrant further validation in a larger cohort of patient-derived tumor models and through confirmatory functional studies.
为解决东北寒地水稻施肥中存在的问题，引进了国际水稻研究所的实地养分管理技术。田间小区试验结果表明，寒地水稻叶片的叶绿素值（SPAD值）在穗分化期、抽穗期与叶片含氮量及叶色卡值（LCC值）之间都呈极显著的正相关（P0.01）。 初步确定寒地水稻的SPAD阈值为38～40，LCC阈值为3.5。与农民习惯施肥（FFP）相比，实地氮肥管理（SSNM）氮肥用量减少25%，千粒重增加0.75 ...g，氮肥利用率显著提高。研究表明，在产量不降低甚至有所增加的前提下，SSNM可以降低氮肥用量，具有在广大寒地稻区推广的前景。
Site-specific nutrient management (SSNM) technology was introduced from International Rice Research Institute (IRRI) to solve the problems in fertilizer application on rice in cold area. A plot experiment showed that there were significantly positive correlations (P0.01)between chlorophyll meter values (SPAD values) and N content in leaves, leaf color chart(LCC)values at panicle initiation and heading stages. Therefore 38-40 was considered as the critical SPAD value, and 3.5 was the critical LCC value for N application. Compared with farmers′ fertilization practice (FFP), the site-specific nitrogen management reduced the total N input by 25%, and increased the 1000-grain weight by 0.75 g, and significantly increased fertilizer-N use efficiency. The results su
This book constitutes the refereed proceedings of the First CCF Conference, NLPCC 2012, held in Beijing, China, during October/November, 2012. The 43 revised full papers presented were carefully ...reviewed and selected from 151 submissions. The papers are organized in topical sections on applications on language computing; fundamentals on language computing; machine translation and multi-lingual information access; NLP for search, ads and social networks; question answering and Web mining.
This paper presents the comprehensive results of landing site topographic mapping and rover localization in Chang＇e-3 mission High-precision topographic products of the landing site with extremely ...high resolutions （up to 0.05 m） were generated from descent images and registered to CE-2 DOM. Local DEM and DOM with 0.02 m resolution were produced routinely at each waypoint along the rover traverse. The lander location was determined to be （19.51256°W, 44.11884°N, -2615.451 m） using a method of DOM matching. In order to reduce error accumulation caused by wheel slippage and IMU drift in dead reckoning, cross-site visual localization and DOM matching localization methods were developed to localize the rover at waypoints; the overall traveled distance from the lander is 114.8 m from cross-site visual localization and 111.2 m from DOM matching lo- calization. The latter is of highest accuracy and has been verified using a LRO NAC image where the rover trajeactory is di- rectly identifiable. During CE-3 mission operations, landing site mapping and rover localization products including DEMs and DOMs, traverse maps, vertical traverse profiles were generated timely to support teleoperation tasks such as obstacle avoid- ance and rover path planning.
Fat mass and obesity-associated gene (FTO) is a member of the Fe (II)- and oxoglutarate-dependent AlkB dioxygenase family and is linked to both obesity and intellectual disability. The role of FTO in ...neurodevelopment and neurogenesis, however, remains largely unknown. Here we show that FTO is expressed in adult neural stem cells and neurons and displays dynamic expression during postnatal neurodevelopment. The loss of FTO leads to decreased brain size and body weight. We find that FTO deficiency could reduce the proliferation and neuronal differentiation of adult neural stem cells in vivo, which leads to impaired learning and memory. Given the role of FTO as a demethylase of N6-methyladenosine (m6A), we went on to perform genome-wide m6A profiling and observed dynamic m6A modification during postnatal neurodevelopment. The loss of FTO led to the altered expression of several key components of the brain derived neurotrophic factor pathway that were marked by m6A. These results together suggest FTO plays important roles in neurogenesis, as well as in learning and memory.
Solar-blind photodetectors have received increasing attentions due to their widely applications in military and civil aspects. However, most of the photodetectors often suffer from relatively slow ...response speeds and high driving voltages. Therefore, it is desirable to develop the self-powered photodetectors with a fast response speed. In this manuscript, self-powered and fast response photodetectors based on β-Ga2O3/4H–SiC pn heterojunction are demonstrated by depositing β-Ga2O3 films on p-type 4H–SiC templates using Pulse Laser Deposition method. The detectors exhibit an ultrahigh current Ion/Ioff ratio more than 103 (∼1655) at the light intensity of 91 μW/cm2 and a fast photo-response speed (a rise time of 11 ms and a decay time of 19 ms) under zero-bias voltage, which are attributed to the quickly separation of the photogenerated electron-hole pairs driven by the built-in electric field at the interface of β-Ga2O3/4H–SiC pn heterojunction. In addition, the detectors also show a responsivity of 10.35 mA/W with a high detectivity of 8.8 × 109 Jones, and the maximum linear dynamic range is reached 64.38 dB. The generality of the above excellent results suggests that the β-Ga2O3/4H–SiC pn photodetectors have great potential in UV detection. Finally, the electronic transport mechanism of the β-Ga2O3/4H–SiC pn heterojunction has been analyzed with the energy band diagram.
•Self-powered photodetectors based on β-Ga2O3/4H–SiC pn heterojunction have been fabricated.•The device exhibited an ultrahigh current on/off ratio more than (103).•The device exhibited fast response rise and decay times of 11/19 ms under zero-bias voltage.
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