Analyzing the Effect of the Intra-Pixel Position of Small PSFs for Optimizing the PL of Optical Subpixel Localization

Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement fields.With unavoidable imaging noise,there is a precision limit(PL)when estimating the target positions on image sensors,which depends on the detected photon count,noise,point spread function(PSF)radius,and PSF’s intra-pixel position.Previous studies have clearly reported the effects of the first three parameters on the PL but have neglected the intra-pixel position information.Here,we develop a localization PL analysis framework for revealing the effect of the intra-pixel position of small PSFs.To accurately estimate the PL in practical applications,we provide effective PSF(e PSF)modeling approaches and apply the Cramér–Rao lower bound.Based on the characteristics of small PSFs,we first derive simplified equations for finding the best PL and the best intra-pixel region for an arbitrary small PSF;we then verify these equations on real PSFs.Next,we use the typical Gaussian PSF to perform a further analysis and find that the final optimum of the PL is achieved at the pixel boundaries when the Gaussian radius is as small as possible,indicating that the optimum is ultimately limited by light diffraction.Finally,we apply the maximum likelihood method.Its combination with e PSF modeling allows us to successfully reach the PL in experiments,making the above theoretical analysis effective.This work provides a new perspective on combining image sensor position control with PSF engineering to make full use of information theory,thereby paving the way for thoroughly understanding and achieving the final optimum of the PL in optical localization.

基于蛋白质半胱氨酸的活性蛋白表达谱分析

蛋白质中的半胱氨酸对维持和调控细胞内的氧化还原平衡起着重要作用,同时它们也是多种蛋白质的功能活性位点,参与诸多生理过程。此外,蛋白质中的半胱氨酸上所发生的一系列翻译后修饰也扩展了蛋白质功能的多样性。随着化学蛋白质组学的发展,基于活性的蛋白表达谱(Activity-basedproteinprofiling,ABPP)分析技术在探究蛋白质半胱氨酸及其翻译后修饰方面取得了很多重要的研究成果。本文简要介绍了用于蛋白质半胱氨酸的活性蛋白表达谱分析方法,讨论了针对蛋白质半胱氨酸及其翻译后修饰的蛋白质组学领域的最新研究,并对该领域的未来发展趋势进行了展望。

Long-term in vivo chimeric cells tracking in non-human primate

Non-human primates(NHPs)are increasingly used in preclinical trials to test the safety and efficacy of biotech-nology therapies.Nonetheless,given the ethical issues and costs associated with this model,it would be highly advantageous to use NHP cellular models in clinical studies.However,developing and maintaining the naive state of primate pluripotent stem cells(PSCs)remains difficult as does in vivo detection of PSCs,thus limiting biotech-nology application in the cynomolgus monkey.Here,we report a chemically defined,xeno-free culture system for culturing and deriving monkey PSCs in vitro.The cells display global gene expression and genome-wide hypometh-ylation patterns distinct from monkey-primed cells.We also found expression of signaling pathways components that may increase the potential for chimera formation.Crucially for biomedical applications,we were also able to integrate bioluminescent reporter genes into monkey PsCs and track them in chimeric embryos in vivo and in vitro.The engineered cells retained embryonic and extra-embryonic developmental potential.Meanwhile,we generated a chimeric monkey carrying bioluminescent cells,which were able to track chimeric cells for more than 2 years in living animals.Our study could have broad utility in primate stem cell engineering and in utilizing chimeric monkey models forclinical studies.

Multiplexed single-cell transcriptome analysis reveals molecular characteristics of monkey pluripotent stem cell lines

Efforts have been made to establish various human pluripotent stem cell lines.However,such methods have not yet been duplicated in non-human primate cells.Here,we introduce a multiplexed single-cell sequencing technique to profile the molecular features of monkey pluripotent stem cells in published culture conditions.The results demonstrate suboptimized maintenance of pluripotency and show that the selected signaling pathways for resetting human stem cells can also be interpreted for establishing monkey cell lines.Overall,this work legitimates the translation of novel human cell line culture conditions to monkey cells and provides guidance for exploring chemical cocktails for monkey stem cell line derivation.

rtcisE2F promotes the self-renewal and metastasis of liver tumorinitiating cells via N^(6)-methyladenosine-dependent E2F3/E2F6 mRNA stability

Liver cancer is highly heterogeneous,and the tumor tissue harbors a variety of cell types.Liver tumor initiating cells(TICs)well contribute to tumor heterogeneity and account for tumor initiation and metastasis,but the molecular mechanisms of liver TIC self-renewal are elusive.Here,we identified a functional read-through rt-circRNA,termed rtcisE2F,that is highly expressed in liver cancer and liver TICs.rtcisE2F plays essential roles in the self-renewal and activities of liver TICs.rtcisE2F targets E2F6 and E2F3 mRNAs,attenuates mRNA turnover,and increases E2F6/E2F3 expression.Mechanistically,rtcisE2F functions as a scaffold of N^(6)-methyladenosine(m^(6)A)reader IGF2BP2 and E2F6/E2F3 mRNA.rtcisE2F promotes the association of E2F6/E2F3 mRNAs with IGF2BP2,and inhibits their association with another m^(6)A reader,YTHDF2.IGF2BP2 inhibits E2F6/E2F3 mRNA decay,whereas YTHDF2 promotes E2F6/E2F3 mRNA decay.By switching m^(6)A readers,rtcisE2F enhances E2F6/E2F3 mRNA stability.E2F6 and E2F3 are both required for liver TIC self-renewal and Wnt/β-catenin activation,and inhibition of these pathways is a potential strategy for preventing liver tumorigenesis and metastasis.In conclusion,the rtcisE2F-IGF2BP2/YTHDF2-E2F6/E2F3-Wnt/β-catenin axis drives liver TIC self-renewal and initiates liver tumorigenesis and metastasis,and may provide a strategy to eliminate liver TICs.

Effect of mesopores on solidification of sirolimus self-microemulsifying drug delivery system

To investigate the influence of mesopores towards the solidification of self-microemulsifying drug delivery system(SMEDDS), mesoporous silica nanospheres(MSNs) and Santa Barbara Amorphous-15(SBA-15) were compared. The MSNs had hydrodynamic size of 195.35 ± 5.82 nm, and pore diameter of 2.70 nm. The SBA-15 had hydrodynamic size of 2312.19 ± 106.93 nm, and pore diameter of 10.91 nm. The MSNs and SBA-15 showed similar loading efficiency of SMEDDS containing sirolimus(SRL). However,MSNs had higher drug dissolution and in vivo absorption, with relative bioavailability of 174.62%. Thus,the length of mesopores played a more important role in solidification of SMEDDS as compared with the pore diameter. This study suggests that the SMEDDS-MSNs can be a potential candidate for oral administration of hydrophobic drugs.

Investigation on induction brazing of profiled cBN wheel for grinding of Ti-6Al-4V

Profiled monolayer cBN wheel was induction brazed for grinding of titanium dovetail slot in this study.Aimed at acquiring a uniform temperature distribution along the profiled surface and reducing the thermal deformation of the brazed wheel,a finite element model was established to investigate the temperature uniformity during induction brazing.A suitable induction coil and the related working parameters were designed and chosen based on the simulation results.Ag-Cu-Ti alloy and cBN grains were applied in the induction brazing experiment.The results showed geometric deformation of the brazed wheel was no more than 0.01 mm and chemical reaction layer were found on the brazed joint interface.Further validation tests were carried out by grinding of Ti-6 Al-4 V alloy.Compared to the electroplated wheel,the brazed wheel showed better performance such as low specific grinding energy and good ground quality in grinding of Ti-6 Al-4 V alloy.Abrasion wear was found to be the main failure mode for the induction brazed wheel,while adhesion and grains pull-out were the main failure mode for the electroplated wheel.

Recent advance of fluorescent probes for detection of drug-induced liver injury markers

Drug-induced liver injury(DILI)is a common and serious adverse drug reaction.At present,DILI is perfectly diagnozed in clinical settings using Roussel Uclaf causality assessment method(RUCAM)in its original version published 1993 and its updated version published 2016,well established worldwide as a diagnostic algorithm with a high sensitivity and specificity.Nevertheless,the search for additional detection methods supporting RUCAM continues.In recent years,with the development of optical imaging technology,fluorescent probes have gradually shown great advantages in the detection and diagnosis of DILI markers such as high sensitivity,anti-interference,real-time monitoring and non-invasive measurement.In this review,the recent advances of fluorescent probes for evaluation of DILI in experimental studies were summarized according to various markers of DILI.We believe that learning about the design and practical application of these probes will contribute to the further development of detection sensors for DILI markers.

Single cell transcriptomic analysis identifies novel vascular smooth muscle subsets under high hydrostatic pressure

Although some co-risk factors and hemodynamic alterations are involved in hypertension progression,their direct biomechanical effects are unclear.Here,we constructed a high-hydrostatic-pressure cell-culture system to imitate constant hypertension and identified novel molecular classifications of human aortic smooth muscle cells(HASMCs)by single-cell transcriptome analysis.Under 100-mmHg(analogous to healthy human blood pressure)or 200-mmHg(analogous to hypertension)hydrostatic pressure for 48 h,HASMCs showed six distinct vascular SMC(VSMC)clusters according to differential gene expression and gene ontology enrichment analysis.Especially,two novel HASMC subsets were identified,named the inflammatory subset,with CXCL2,CXCL3 and CCL2 as markers,and the endothelial-function inhibitory subset,with AKR1C2,AKR1C3,SERPINF1 as markers.The inflammatory subset promoted CXCL2&3 and CCL2 chemokine expression and secretion,triggering monocyte migration;the endothelial-function inhibitory subset secreted SERPINF1 and accelerated prostaglandin F2αgeneration to inhibit angiogenesis.The expression of the two VSMC subsets was greatly increased in arterial media from patients with hypertension and experimental animal models of hypertension.Collectively,we identified high hydrostatic pressure directly driving VSMCs into two new subsets,promoting or exacerbating endothelial dysfunction,thereby contributing to the pathogenesis of cardiovascular diseases.