NIR-to-NIR UCL/T_1-weighted MR/CT multimodal imaging by NaYbF_4:Tm@NaGdF_4:Yb-PVP upconversion nanoparticles

Multimodal imaging nanoprobes are urgently sought because they can integrate different imaging function into individual nanoplatform and provide more comprehensive and accurate information for the diagnosis of early-stage tumor.Lanthanide-based upconversion nanoparticles(UCNPs) are regarded as promising nanoplatforms to fabricate these probes.Herein,we firstly developed the active core-active shell structured NaYbF_4:Tm@NaGdF_4:Yb-PVP UCNPs with the average diameter of 13.23±0.96 nm as multimodal imaging probes.These water-dispersible nanoprobes presented excellent near-infrared to near-infrared(NIR-to-NIR) upconversion luminescence(UCL) performance,which is favorable for optical bioimaging due to deeper tissue penetration and autofluorescence reduction.After coated with the NaGdF_4:Yb active shell,the UCL emission intensity at 800 nm increased by 7.2 times.These nanoprobes exhibited a desirable longitudinal relaxivity(r_1=3.58 L/(mmol s)) and strong X-ray attenuation property(58.84 HU L/g).The cytotoxicity assessment,histology analysis and biodistribution study revealed that NaYbF_4:Tm@NaGdF_4:Yb-PVP UCNPs had relatively low cytotoxicity and negligible organ toxicity.These UCNPs were applied for NIR-to-NIR UCL imaging in vivo.More importantly,the detection of small tumor was successfully achieved under T_1-weighted MRI and CT imaging modalities after intravenous injection of these UCNPs.These results revealed that NaYbF_4:Tm@NaGdF_4:Yb-PVP UCNPs could serve as promising NIR-to-NIR UCL/MRI/CT trimodal imaging probes.

Online Pattern Recognition and Data Correction of PMU Data Under GPS Spoofing Attack

Smart grids are increasingly dependent on data with the rapid development of communication and measurement.As one of the important data sources of smart grids,phasor measurement unit(PMU)is facing the high risk from attacks.Compared with cyber attacks,global position system(GPS)spoofing attacks(GSAs)are easier to implement because they can be exploited by portable devices,without the need to access the physical system.Therefore,this paper proposes a novel method for pattern recognition of GSA and an additional function of the proposed method is the data correction to the phase angle difference(PAD)deviation.Specifically,this paper analyzes the effect of GSA on PMU measurement and gives two common patterns of GSA,i.e.,the step attack and the ramp attack.Then,the method of estimating the PAD deviation across a transmission line introduced by GSA is proposed,which does not require the line parameters.After obtaining the estimated PAD deviations,the pattern of GSA can be recognized by hypothesis tests and correlation coefficients according to the statistical characteristics of the estimated PAD deviations.Finally,with the case studies,the effectiveness of the proposed method is demonstrated,and the success rate of the pattern recognition and the online performance of the proposed method are analyzed.

A 1,8-naphthalimide-derived turn-on fluorescent probe for imaging lysosomal nitric oxide in living cells

Nitric oxide has played an important role in many physiological and pathological processes as a kind of important gas signal molecules. In this work, a new fluorescent probe LysoNO-Naph for detecting NO in lysosomes based on 1,8-naphthalimide was reported. LysoNO-Naph has sub-groups of o-phenylene- diamine as a NO reaction site and 4-（2-aminoethyl）-morpholine as a lysosome-targetable group. This probe exhibited good selectivity and high sensitivity （4.57 μmol/L） toward NO in a wide pH range from 4 to 12. Furthermore, LysoNO-Naph can be used for imaging NO in lysosomes in living cells.

SNAP-tag fluorogenic probes for wash free protein labeling

Protein labeling by using a protein tag and tag-specific fluorescent probes is increasingly becoming a useful technique for the real-time imaging of proteins in living cells. SNAP-tag as one of the most prominent fusion tags has been widely used and already commercially available. Recently, various fluorogenic probes for SNAP-tag based protein labeling were reported. Owing to turn-on fluorescence response, fluorogenic probes for SNAP-tag minimize the fluorescence background caused by unreacted or nonspecifically bound probes and allow for direct imaging in living cells without wash-out steps. Thus,real-time analysis of protein localization, dynamics and interactions has been made possible by SNAP-tag fluorogenic probes. In this review,we describe the design strategies of fluorogenic probes for SNAP-tag and their applications in cellular protein labeling.