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DNAzyme as a rising gene-silencing agent in theranostic settings

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Neural Regeneration Research 2022年第9期17卷 1989-1990页

作者： nan Zhang Neuroscience Program Department of NeurologyHouston Methodist Research InstituteHoustonTXUSA

Decades of biochemical studies have advanced DNA beyond its primary role as genetic blueprint.DNAzymes are single-stranded enzymatic DNA molecules that do not exist in nature.They are ideal candidates for gene silencing owing to their scalability by solid-phase synthesis(without batch variations),reprogrammability by directed evolution and local sequence alterations,compatibility with diverse delivery methods,and capability of achieving high catalytic turnover independent of any auxiliary proteins.With these unique features,various artificially evolved DNAzymes have been employed as theranostic tools in designing biosensors and logic gates,RNA/DNA cleavage and ligation,phosphorylation and dephosphorylation,DNA photorepair,and peptide side-chain modifications,to name but a few(Ponce-Salvatierra et al.,2021).This perspective will focus on the functional aspects and therapeutic potentials of RNA-cleaving DNAzymes.

关键词： compatibility auxiliary batch

Flexible double narrowband near-infrared photodetector based on PMMA/core-shell upconversion nanoparticle composites

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Journal of Rare Earths 2022年第2期40卷 211-217,I0002页

作者： Ya’nan Ji Donglei Zhou nan Wang nan Ding Wen Xu Hongwei Song State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

Flexible narrowband near infrared(NIR)photodetectors(PDs)are urgently in demand in the fastdeveloping era of flexible electronics,due to their crucial roles in various innovative applications.Hence,we designed and synthesized the core-shell structured NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)upconversion nanoparticles(UCNPs),which can be pumped by the 808 and 980 nm lights.The upconversion luminescence(UCL)are significantly enhanced after being assembled with the opal photonic crystals(OPCs)due to the photonic crystal effect,with 55 and 48 folds of enhancement factors under illuminations of 808 and 980 nm lights,respectively.Based on this hybrid,the flexible narrowband PDs were successfully fabricated on the PET substrate with the structure of OPCs/NaYF4:Yb^(3+),Er^(3+)@Nd^(3+)/MAPbl3,which displays excellent detection performance to double narrowband NIR light(808 and 980 nm)benefiting from the amplified UCL,with responsivity of 8.79 and 7.39 A/W,detectivity of 3.01×10^(11)and2.68×10^(11)cm·Hz^(1/2)/W for 808 and 980 nm lights detection respectively,along with short response time in the range of 120-160 ms.Furthermore,the OPCs/NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)/MAPbI3 double narrowband PDs display low photodetection power threshold(0.05 W/cm2),outstanding flexibility,prominent moisture resistance,and good long-time stability.This work displays a new concept of narrowband NIR PDs,which open a new field for specific NIR light detections.

关键词： Upconversion luminescence Upconversion enhancement Narrow-band near-infrared photodetection Flexible photodetectors Rare earths

Common quantitative characteristics of music melodies——pursuing the constrained entropy maximization casually in composition

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Science China(Information Sciences) 2022年第7期65卷 240-242页

作者： nan nan Xiaohong GUAN Yixin WANG Youtian DU MOE KLINNS Lab Faculty of Electronic and Information Engineering Xi'an Jiaotong University Center for Intelligent and Networked Systems Tsinghua University

Music with a beautiful melody has been appreciated by humankind for thousands of years. Almost all music is generally tonal, e.g., Western music originated from ancient Greece and developed for more than 300 years from Baroque to classical, romantic, and modern music. Tonal music has a tonal center with a melody named tonic, and it is based on a specific pitch series called mode scale and harmonic progressions. On the contrary,

关键词： Power Law music melody variations complementary communitive distribution entropy functional optimization

A Survey of Voltage-Controlled-Oscillator-Based ?∑ ADCs

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Tsinghua Science and Technology 2022年第3期27卷 472-480页

作者： Yi Zhong nan Sun Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Department of Electrical and Computer Engineering The University of Texas at AustinAustinTX 78712USA

The benefits of technology scaling have fueled interest in realizing time-domain oversampling(?∑) of Analog-to-Digital Converters(ADCs). Voltage-Controlled Oscillators(VCO) are increasingly used to design ?∑ADCs because of their simplicity, high digitization, and low-voltage tolerance, making them a promising candidate to replace the classical Operational Transconductance Amplifier(OTA) in ?∑ ADC design. This work aims to provide a summary of the fully VCO-based ?∑ ADCs that are highly digital and scaling-friendly. This work presents a review of first-order and high-order VCO-based ?∑ ADCs with several techniques and architectures to mitigate the nonidealities introduced by VCO, achieving outstanding power efficiency. The contributions and drawbacks of these techniques and architectures are also discussed.

关键词： Voltage-Controlled Oscillator(VCO) Analog-to-Digital Converter(ADC) oversampling(?∑)ADC time-domain signal processing VCO-based?∑ADC

Rational design of bimetallic catalysts for electrochemical CO_(2)reduction reaction:A review

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Science China Chemistry 2023年第5期66卷 1288-1317页

作者： Minhan Li Jia-nan Zhang College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

The electrochemical CO_(2)reduction reaction(eCO_(2)RR)is a compelling approach to convert CO_(2)into high-value fuels and chemicals using renewable energies.The rational design of catalysts is of great importance for achieving outstanding performance of this process.Metal-based catalysts have been drawing enormous attention in eCO_(2)RR due to their excellent catalytic performance and flexible selectivity.In the pursuit of overcoming the inherent disadvantages of monometallic catalysts and achieving breakthroughs in the catalytic performance,bimetallic strategy has been receiving extensive concerns and achieving remarkable results over decades.In this review,we attempt to give a comprehensive review on the bimetallic catalysts that are used for eCO_(2)RR.The effects in bimetallic catalysts that contribute to the enhanced eCO_(2)RR performance are first analyzed,demonstrating the superiority of bimetallic strategy.Then,the structural design of bimetallic catalysts is discussed as it plays a key role in eCO_(2)RR.Finally,the current advances and rules of selectivity of bimetallic catalysts in eCO_(2)RR are summarized based on the selectivity behaviors.By reviewing efforts devoted in this field,this review is believed to present a timely overview of the progress of bimetallic eCO_(2)RR catalysts and to offer potential future directions in the aim of developing highly efficient catalysts for eCO_(2)RR.

关键词： electrochemical CO_(2)reduction bimetallic catalyst electronic effect tandem effect structural design

The Quasar Candidate Catalogs of DESI Legacy Imaging Survey Data Release 9

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Research in Astronomy and Astrophysics 2022年第9期22卷 267-277页

作者： Zizhao He nan Li Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Quasars can be used to measure baryon acoustic oscillations at high redshift, which are considered as direct tracers of the most distant large-scale structures in the universe. It is fundamental to select quasars from observations before implementing the above research. This work focuses on creating a catalog of quasar candidates based on photometric data to provide primary priors for further object classification with spectroscopic data in the future, such as the Dark Energy Spectroscopic Instrument(DESI) Survey. We adopt a machine learning algorithm(Random Forest, RF) for quasar identification. The training set includes 651,073 positives and 1,227,172 negatives, in which the photometric information are from DESI Legacy Imaging Surveys(DESI-LIS) and Wide-field Infrared Survey Explore(WISE), and the labels are from a database of spectroscopically confirmed quasars based on Sloan Digital Sky Survey and the Set of Identifications& Measurements and Bibliography for Astronomical Data. The trained RF model is applied to point-like sources in DESI-LIS Data Release 9. To quantify the classifier’s performance, we also inject a testing set into the to-be-applied data.Eventually, we obtained 1,953,932 Grade-A quasar candidates and 22,486,884 Grade-B quasar candidates out of425,540,269 sources(~5.7%). The catalog covers ~99% of quasars in the to-be-applied data by evaluating the completeness of the classification on the testing set. The statistical properties of the candidates agree with that given by the method of color-cut selection. Our catalog can intensely decrease the workload for confirming quasars with the upcoming DESI data by eliminating enormous non-quasars but remaining high completeness. All data in this paper are publicly available online.

关键词： galaxies:quasars:general catalogs methods:statistical

Scale problem:Influence of grid spacing of digital elevation model on computed slope and shielded extra-terrestrial solar radiation

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Frontiers of Earth Science 2020年第1期14卷 171-187页

作者： nan CHEN Key Laboratory of Spatial Data Mining&Information Sharing(Ministry of Education) Fuzhou UniversityFuzhou 350108 China Spatial Information Research Center of Fujian Province Fuzhou UniversityFuzhou 350108 China

Solar radiation is the primary energy source that drives many of Earth’s physical and biological processes and determines the patterns of climate and productivity on the surface of the Earth.A fundamental proportion of solar radiation is composed of shielded extraterrestrial solar radiation(SESR),which can be computed using the slope and aspect derived from a digital elevation model(DEM).The objective of this paper is to determine the influence of the grid spacing of the DEM(the influence of the scale of the DEM)on the errors of slope,aspect and SESR.This paper puts forward the concepts of slope representation error,aspect representation error,and SESR representation error and then studies the relations among these errors and the grid spacing of DEMs.We find that when the grid spacing of a DEM becomes coarser,the average SESR increases;the increase in SESR is dominated by the grid cells of the DEM with a negative slope representation error,whereas SESR generally decreases in the grid cells with a positive slope representation error.Although the grid spacing varies,the distribution of the percentages of positive SESR representation errors on the slope,which is classified into 11 slope intervals,is independent of the grid spacing;this distribution is concentrated across some slope intervals.Moreover,the average absolute value and mean square error of the SESR representation error are closely related to those of the slope representation error and the aspect representation error.The findings in this study may be useful for predicting and reducing the errors in SESR measurements and may help to avoid mistakes in foture research and in practical applications in which SESR is the data of interest or plays a vital role in an analysis.

关键词： scale problem digital elevation model grid spacing slope shielded extra-terrestrial solar radiation

Is neurotrophic factor a second language that neuron and tooth speak?

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Neural Regeneration Research 2021年第9期16卷 1803-1804页

作者： nan Xiao Department of Biomedical Sciences Arthur A.Dugoni School of DentistryUniversity of the PacificSan FranciscoCAUSA

Neurotrophic factors are growth factors that can nourish neurons and promote neuron survival and regeneration. Dental origin mesenchymal stem cells express various neurotrophic factors during tooth development and the... 详细信息

关键词： speak differentiation. Dental

Remote detection of alpha radiation source by optical method

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光电子快报:英文版 2023年第7期19卷 405-409页

作者： LI Ningning ZHANG nan Institute of Modern Optics Nankai UniversityTianjin 300350China

To solve the problem that the conventional detection technique of alpha radiation sources is unable to achieve remote detection and not suitable for detecting alpha radiation sources with complex morphology,remote detection of alpha radiation sources by measuring the fluorescence induced by the interaction between alpha particles and nitrogen molecules is investigated in this paper.In dark conditions,nitrogen fluorescence is collected by the optical system with an aperture of 50 mm and detected by a photomultiplier tube working in the photon counting mode.The alpha radiation source with total activity of 7.3 k Bq and unit area activity of 49 Bq/cm^(2) can be detected within 30 s at a distance of 0.6 m.The detection limit of the alpha radiation source detection system proposed in this paper ranks among the top in the related research fields.

关键词： Remote source system