Deep learning enhanced NIR-Ⅱ volumetric imaging of whole mice vasculature

Fluorescence imaging through the second near-infrared window(NIR-Ⅱ,1000–1700 nm) allows in-depth imaging.However, current imaging systems use wide-field illumination and can only provide low-contrast 2D information, without depth resolution. Here, we systematically apply a light-sheet illumination, a time-gated detection, and a deep-learning algorithm to yield high-contrast high-resolution volumetric images. To achieve a large Fo V(field of view) and minimize the scattering effect, we generate a light sheet as thin as 100.5 μm with a Rayleigh length of 8 mm to yield an axial resolution of 220 μm. To further suppress the background, we time-gate to only detect long lifetime luminescence achieving a high contrast of up to 0.45 Icontrast. To enhance the resolution, we develop an algorithm based on profile protrusions detection and a deep neural network and distinguish vasculature from a low-contrast area of 0.07 Icontrast to resolve the 100μm small vessels. The system can rapidly scan a volume of view of 75 × 55 × 20 mm3and collect 750 images within 6mins. By adding a scattering-based modality to acquire the 3D surface profile of the mice skin, we reveal the whole volumetric vasculature network with clear depth resolution within more than 1 mm from the skin. High-contrast large-scale 3D animal imaging helps us expand a new dimension in NIR-Ⅱ imaging.

Super-resolution fluorescence polarization microscopy

Fluorescence polarization is related to the dipole orientation of chromophores,making fuores-cence polarization microscopy possible to_reveal structures and functions of tagged cellularorganelles and biological macromolecules.Several recent super resolution techniques have beenapplied to fluorescence polarization microscopy,achieving dipole measurement at nanoscale.In this review,we summarize both difraction limited and super resolution fluorescence polari-zation microscopy techniques,as well as their applications in biological imaging.

Effects of Silicon Fertilizer on Growth of Kohlrabi(Brassica oleracea L.var.caulorapa DC.)and Plutella xylostella

[Objectives]This study was conducted to investigate the control effects of silicon fertilizer on growth of kohlrabi(Brassica oleracea L.var.caulorapa DC.)and Plutella xylostella.[Methods]Yougui and Guishen were selected and sprayed onto kohlrabi for 1,2 and 3 times,forming difference treatments.[Results]Spraying the two kinds of silicon fertilizers for different times promoted the growth of leaf length,leaf width and leaf thickness of kohlrabi,improved chlorophyll contents in kohlrabi leaves and corm yield,and adversely affected P.xylostella.Furthermore,higher treatment times led to a more remarkably effect and higher harm to P.xylostella.[Conclusions]In production,spraying silicon fertilizer onto maize for 2-3 times could realize the purposes of improving kohlrabi yield and alleviating damage by P.xylostella.

Effects of AOS on Bt's Adhesion Amount on Vegetable Leaves and Its Insecticidal Effect

[Objectives] This study was conducted to investigate the safety of surfactants AOS and Tween 80 on Bt and their effects on Bt's adhesion amount on crop leaves and its field efficacy. [Methods] Certain concentrations of AOS and Tween 80 were added to Bt liquid to check the effects of the surfactants on Bt spore germination, the adhesion amount of Bt on vegetable leaves and the field efficacy on beet armyworm. [Results] After treatment with surfactants AOS and Tween 80, Bt spores germinated normally. After adding AOS, the adhesion amounts of Bt spores on scallion, kohlrabi, radish and Chinese cabbage leaves were 209.75, 249.00, 274.00 and 281.75, respectively, which was 3.8, 2.2, 2.0 and 1.6 times higher than the CK. After adding Tween 80, the adhesion amounts of Bt spores on scallion, kohlrabi, radish and Chinese cabbage leaves were 198.25, 203.25, 233.00 and 236.75, respectively, which were 3.6, 1.8, 1.7 and 1.4 times higher than the CK, respectively. The average field insecticidal effect of the Bt liquid reached 81.3% and 79.5% after the addition of surfactants AOS and Tween 80, respectively, while the average insecticidal effect of the CK without the addition of a surfactant was only 53.3%, which was remarkably lower than above two values. [Conclusions] Surfactants AOS and Tween 80 are safe for Bt; and the addition of surfactants AOS and Tween 80 significantly increased the amount of Bt attached to vegetable leaves, and significantly improved the control efficacy of pests on plants rich in cuticle.

Efficacy Tests of Nine Insecticides on Tetranychus truncatus Ehara

[Objectives] This study was conducted to screen out pesticides that are highly effective against Tetranychus truncatus Ehara. [Methods] Nine kinds of pesticides were used to control pests on soybean. A petri dish efficacy test was first performed in laboratory,then a leaf efficacy test was performed in a greenhouse,and finally,three kinds of agents with good efficacy in the two tests were selected for field control tests. [Results] The indoor and outdoor test results showed that abamectin was the best agent,which showed efficacy higher than 96%,followed by bifenthrin,whose efficacy was higher than 93%. It can be seen that abamectin is the best choice for the prevention and control of T. truncatus,and bifenthrin can also be used according to the situation. [Conclusions] This study provides a theoretical basis for the control of T. truncatus.

Effects of Two Silicon Fertilizers on Maize Growth and Tetranychus truncatus Ehara

[ Objectives] This study was conducted to investigate the effect of silicon fertilizer on maize growth and Tetranychus truncatus Ehara. [ Methods ] Yougui and Guishen were selected and sprayed onto maize for 1, 2 and 3 times, forming difference treatments. [ Results ] Spraying the two kinds of silicon fertilizers for different times promoted the growth of plant height, leaf length, leaf width and leaf thickness of maize, increased chlorophyll contents in maize leaves and yield of single ear, and also adversely affected T. truncatus （i. e. , increased the death rate of T. truncatus）. The more the treatment times of silicon fertilizer, the more remarkable the effect, and the higher the adverse effect on T. truncatus. [ Conclusions] In production, spraying silicon fertilizer onto maize for 2 -3 times could realize the purposes of increasing maize yield and alleviating the danlage by T. truncatus.

Ultra-high spatio-temporal resolution imaging with parallel acquisition-readout structured illumination microscopy(PAR-SIM)

Structured illumination microscopy(SIM)has emerged as a promising super-resolution fluorescence imaging technique,offering diverse configurations and computational strategies to mitigate phototoxicity during real-time imaging of biological specimens.Traditional efforts to enhance system frame rates have concentrated on processing algorithms,like rolling reconstruction or reduced frame reconstruction,or on investments in costly sCMOS cameras with accelerated row readout rates.In this article,we introduce an approach to elevate SIM frame rates and region of interest(ROI)coverage at the hardware level,without necessitating an upsurge in camera expenses or intricate algorithms.Here,parallel acquisition-readout SIM(PAR-SIM)achieves the highest imaging speed for fluorescence imaging at currently available detector sensitivity.By using the full frame-width of the detector through synchronizing the pattern generation and image exposure-readout process,we have achieved a fundamentally stupendous information spatial-temporal flux of 132.9 MPixels·s^(−1),9.6-fold that of the latest techniques,with the lowest SNR of−2.11 dB and 100 nm resolution.PAR-SIM demonstrates its proficiency in successfully reconstructing diverse cellular organelles in dual excitations,even under conditions of low signal due to ultra-short exposure times.Notably,mitochondrial dynamic tubulation and ongoing membrane fusion processes have been captured in live COS-7 cell,recorded with PAR-SIM at an impressive 408 Hz.We posit that this novel parallel exposure-readout mode not only augments SIM pattern modulation for superior frame rates but also holds the potential to benefit other complex imaging systems with a strategic controlling approach.

Contrast-enhanced fluorescence microscope by LED integrated excitation cubes

Fluorescence microscopy is a powerful tool for scientists to observe the microscopic world,and the fluorescence excitation light source is one of the most critical components.To compensate for the short operation lifetime,integrated light sources,and low excitation efficiency of conventional light sources such as mercury,halogen,and xenon lamps,we designed an LED-integrated excitation cube(LEC)with a decentralized structure and high optical power density.Using a Fresnel lens,the light from the light-emitting diode(LED)was effectively focused within a 15 mm mounting distance to achieve high-efficiency illumination.LEC can be easily designed in the shape of fluorescence filter cubes for installation in commercial fluorescence microscopes.LECs’optical efficiency is 1–2 orders of magnitude higher than that of mercury lamps;therefore,high-quality fluorescence imaging with spectral coverage from UV to red can be achieved.By replacing conventional fluorescence filter cubes,LEC can be easily installed on any commercial fluorescence microscope.A built-in LEC driver can identify the types of LEDs in different spectral bands to adopt the optimal operating current and frequency of pulses.Moreover,high-contrast images can be achieved in pulse mode by time-gated imaging of long-lifetime luminescence.

Polarized upconversion emission at metasurface

Leveraging the resonant modes of all-dielectric metasurfaces,specifically quasi-bound state in the continuum and Mie resonances,the precise orthogonal polarization control has been realized.

Super-resolution dipole orientation mapping via polarization demodulation

Fluorescence polarization microscopy(FPM)aims to detect the dipole orientation of fluorophores and to resolve structural information for labeled organelles via wide-field or confocal microscopy.Conventional FPM often suffers from the presence of a large number of molecules within the diffraction-limited volume,with averaged fluorescence polarization collected from a group of dipoles with different orientations.Here,we apply sparse deconvolution and least-squares estimation to fluorescence polarization modulation data and demonstrate a super-resolution dipole orientation mapping(SDOM)method that resolves the effective dipole orientation from a much smaller number of fluorescent molecules within a sub-diffraction focal area.We further apply this method to resolve structural details in both fixed and live cells.For the first time,we show that different borders of a dendritic spine neck exhibit a heterogeneous distribution of dipole orientation.Furthermore,we illustrate that the dipole is always perpendicular to the direction of actin filaments in mammalian kidney cells and radially distributed in the hourglass structure of the septin protein under specific labelling.The accuracy of the dipole orientation can be further mapped using the orientation uniform factor,which shows the superiority of SDOM compared with its wide-field counterpart as the number of molecules is decreased within the smaller focal area.Using the inherent feature of the orientation dipole,the SDOM technique,with its fast imaging speed(at sub-second scale),can be applied to a broad range of fluorescently labeled biological systems to simultaneously resolve the valuable dipole orientation information with super-resolution imaging.

Laparoscopic versus open pancreaticoduodenectomy for pancreatic ductal adenocarcinoma:a propensity score matching analysis

Background:A growing body of evidence supports the use of laparoscopic pancreaticoduodenectomy(LPD)as an efficient and feasible surgical technique.However,few studies have investigated its applicability in pancreatic ductal adenocarcinoma(PDAC),and the long-term efficacy of LPD on PDAC remains unclear.This study aimed to compare the short-and long-term outcomes between LPD and open pancreaticoduodenectomy(OPD)for PDAC.Methods:The data of patients who had OPD or LPD for PDAC between January 2013 and September 2017 were retrieved.Their postoperative outcomes and survival were compared after propensity score matching.Results:A total of 309 patients were included.After a 2:1 matching,93 cases in the OPD group and 55 in the LPD group were identified.Delayed gastric emptying(DGE),particularly grade B/C DGE,occurred less frequently in the LPD group than in the OPD group(1.8%vs.36.6%,P<0.001;1.8%vs.22.6%,P=0.001).The overall complication rates were significantly lower in the LPD group than in the OPD group(49.1%vs.71.0%,P=0.008),whereas the rates of major complications were similar(10.9%vs.14.0%,P=0.590).In addition,the median overall survival was comparable between the two groups(20.0 vs.18.7 months,P=0.293).Conclusion:LPD was found to be technically feasible with efficacy similar to OPD for patients with PDAC.

New strategy for designing orangish-redemitting phosphor via oxygen-vacancyinduced electronic localization

Phosphor-converted white-light-emitting diodes(pc-WLED)have been extensively employed as solid-state lighting sources,which have a very important role in people’s daily lives.However,due to the scarcity of the red component,it is difficult to realize warm white light efficiently.Hence,red-emitting phosphors are urgently required for improving the illumination quality.In this work,we develop a novel orangish-red La_(4)GeO_(8):Bi^(3+) phosphor,the emission peak of which is located at 600 nm under near-ultraviolet(n-UV)light excitation.The full width at half maximum(fwhm)is 103 nm,the internal quantum efficiency(IQE)exceeds 88%,and the external quantum efficiency(EQE)is 69%.According to Rietveld refinement analysis and density functional theory(DFT)calculations,Bi^(3+) ions randomly occupy all La sites in orthorhombic La_(4)GeO_(8).Importantly,the oxygen-vacancy-induced electronic localization around the Bi3+ions is the main reason for the highly efficient orangish-red luminescence.These results provide a new perspective and insight from the local electron structure for designing inorganic phosphor materials that realize the unique luminescence performance of Bi^(3+) ions.

Microscopic inspection and tracking of single upconversion nanoparticles in living cells

Nanoparticles have become new tools for cell biology imaging1,sub-cellular sensing2,super-resolution imaging3,4 and drug delivery5.Long-term 3D tracking of nanoparticles and their intracellular motions have advanced the understanding of endocytosis and exocytosis as well as of active transport processes6–8.The sophisticated operation of correlative optical-electron microscopy9,10 and scientific-grade cameras is often used to study intercellular processes.Nonetheless,most of these studies are still limited by the insufficient sensitivity for separating a single nanoparticle from a cluster of nanoparticles or their aggregates8,11,12.Here we report that our eyes can track a single fluorescent nanoparticle that emits over 4000 photons per 100 milliseconds under a simple microscope setup.By tracking a single nanoparticle with high temporal,spectral and spatial resolution,we show the measurement of the local viscosity of the intracellular environment.Moreover,beyond the colour domain and 3D position,we introduce excitation power density as the fifth dimension for our eyes to simultaneously discriminate multiple sets of single nanoparticles.

Silica shell-assisted synthetic route for mono-disperse persistent nanophosphors with enhanced in vivo recharged near-infrared persistent luminescence

Near-infrared （NIR） persistent-luminescence nanoparticles have emerged as a new class of background-free contrast agents that are promising for in vivo imaging. The next key roadblock is to establish a robust and controllable method for synthesizing monodisperse nanoparticles with high luminescence brightness and long persistent duration. Herein, we report a synthesis strategy involving the coating/etching of the SiO2 shell to obtain a new class of small NIR highly persistent luminescent ZnGa2O4：Cr^3＋,Sn^4＋（ZGOCS） nanoparticles. The optimized ZGOCS nanoparticles have an excellent size distribution of -15 nm without any agglomeration and an NIR persistent luminescence that is enhanced by a factor of 13.5, owing to the key role of the SiO2 shell in preventing nanoparticle agglomeration after annealing. The ZGOCS nanoparticles have a signal-to-noise ratio -3 times higher than that of previously reported ZnGa204：Cr^3＋ （ZGC-1） nanoparticles as an NIR persistent-luminescence probe for in vivo bioimaging. Moreover, the persistent-luminescence signal from the ZGOCS nanoparticles can be repeatedly re-charged in situ with external excitation by a white light- emitting diode; thus, the nanopartides are suitable for long-term in vivo imaging applications. Our study suggests an improved strategy for fabricating novel high-performance optical nanoparticles with good biocompatibility.

Mirror-enhanced super-resolution microscopy

Axial excitation confinement beyond the diffraction limit is crucial to the development of next-generation,super-resolution microscopy.STimulated Emission Depletion(STED)nanoscopy offers lateral super-resolution using a donut-beam depletion,but its axial resolution is still over 500 nm.Total internal reflection fluorescence microscopy is widely used for single-molecule localization,but its ability to detect molecules is limited to within the evanescent field of~100 nm from the cell attachment surface.We find here that the axial thickness of the point spread function(PSF)during confocal excitation can be easily improved to 110 nm by replacing the microscopy slide with a mirror.The interference of the local electromagnetic field confined the confocal PSF to a 110-nm spot axially,which enables axial super-resolution with all laser-scanning microscopes.Axial sectioning can be obtained with wavelength modulation or by controlling the spacer between the mirror and the specimen.With no additional complexity,the mirror-assisted excitation confinement enhanced the axial resolution six-fold and the lateral resolution two-fold for STED,which together achieved 19-nm resolution to resolve the inner rim of a nuclear pore complex and to discriminate the contents of 120 nm viral filaments.The ability to increase the lateral resolution and decrease the thickness of an axial section using mirror-enhanced STED without increasing the laser power is of great importance for imaging biological specimens,which cannot tolerate high laser power.

A stoichiometric terbium-europium dyad molecular thermometer: energy transfer properties

The optical thermometer has shown great promise for use in the fields of aeronautical engineering,environmental monitoring and medical diagnosis.Self-referencing lanthanide thermo-probes distinguish themselves because of their accuracy,calibration,photostability,and temporal dimension of signal.However,the use of conventional lanthanidedoped materials is limited by their poor reproducibility,random distance between energy transfer pairs and interference by energy migration,thereby restricting their utility.Herein,a strategy for synthesizing hetero-dinuclear complexes that comprise chemically similar lanthanides is introduced in which a pair of thermosensitive dinuclear complexes,cycTb-phEu and cycEu-phTb,were synthesized.Their structures were geometrically optimized with an internuclear distance of approximately 10.6Å.The sensitive linear temperature-dependent luminescent intensity ratios of europium and terbium emission over a wide temperature range(50–298 K and 10–200 K,respectively)and their temporal dimension responses indicate that both dinuclear complexes can act as excellent self-referencing thermometers.The energy transfer from Tb^(3+)to Eu^(3+)is thermally activated,with the most important pathway involving the ^(7)F_(1) Eu^(3+)J-multiplet at room temperature.The energy transfer from the antenna to Eu^(3+)was simulated,and it was found that the most important ligand contributions to the rate come from transfers to the Eu^(3+)upper states rather than direct ligand–metal transfer to 5D1 or 5D0.As the first molecular-based thermometer with clear validation of the metal ratio and a fixed distance between the metal pairs,these dinuclear complexes can be used as new materials for temperature sensing and can provide a new platform for understanding the energy transfer between lanthanide ions.

A homogeneous DNA assay by recovering inhibited emission of rare earth ions-doped upconversion nanoparticles

Robust and easy-to-use kits specific for a particular DNA sequence are desirable for early detection of diseases. However, the major challenge with these tests is often the background fluorescence artifacts arising from biological species due to employing UV and visible range of light. Here, we have reported a near-infrared (NIR) fluorescence "turn-on" kit based on rare earth ions doped nanoparticles, upconversion nanoparticles (UCNPs), and gold nanoparticles (AuNPs), which forms a fluorescence-quencher pair,brought together by a hairpin structure through the formation of double-stranded DNA (dsDNA), with quenched upconversion luminescence. In the presence of analytes, the molecular beacon opens to push AuNPs away from UCNPs, with a distance longer than the efficient quenching distance, so that the inhibited upconversion emission will be restored. We demonstrated that this assay provides a homogeneous, facile, simple and highly selective HIV-1 based DNA detection system with restore efficiency up to 85%, and the detection limit of 5 nm.

Polarization modulation with optical lock-in detection reveals universal fluorescence anisotropy of subcellular structures in live cells

The orientation of fluorophores can reveal crucial information about the structure and dynamics of their associated subcellular organelles.Despite significant progress in super-resolution,fluorescence polarization microscopy remains limited to unique samples with relatively strong polarization modulation and not applicable to the weak polarization signals in samples due to the excessive background noise.Here we apply optical lock-in detection to amplify the weak polarization modulation with super-resolution.This novel technique,termed optical lock-in detection super-resolution dipole orientation mapping(OLID-SDOM),could achieve a maximum of 100 frames per second and rapid extraction of 2D orientation,and distinguish distance up to 50 nm,making it suitable for monitoring structural dynamics concerning orientation changes in vivo.OLID-SDOM was employed to explore the universal anisotropy of a large variety of GFP-tagged subcellular organelles,including mitochondria,lysosome,Golgi,endosome,etc.We found that OUF(Orientation Uniformity Factor)of OLID-SDOM can be specific for different subcellular organelles,indicating that the anisotropy was related to the function of the organelles,and OUF can potentially be an indicator to distinguish normal and abnormal cells(even cancer cells).Furthermore,dual-color super-resolution OLID-SDOM imaging of lysosomes and actins demonstrates its potential in studying dynamic molecular interactions.The subtle anisotropy changes of expanding and shrinking dendritic spines in live neurons were observed with real-time OLID-SDOM.Revealing previously unobservable fluorescence anisotropy in various samples and indicating their underlying dynamic molecular structural changes,OLID-SDOM expands the toolkit for live cell research.

Frequency-domain diagonal extension imaging

The pixel size of a charge-coupled device(CCD)camera plays a major role in the image resolution,and the square pixels are attributed to the physical anisotropy of the sampling frequency.We synthesize the high sampling frequency directions from multiple frames acquired with different angles to enhance the resolution by 1.4×over conventional CCD orthogonal sampling.To directly demonstrate the improvement of frequency-domain diagonal extension(FDDE)microscopy,lens-free microscopy is used,as its resolution is dominantly determined by the pixel size.We demonstrate the resolution enhancement with a mouse skin histological specimen and a clinical blood smear sample.Further,FDDE is extended to lens-based photography with an ISO 12233 resolution target.This method paves a new way for enhancing the image resolution for a variety of imaging techniques in which the resolution is primarily limited by the sampling pixel size,for example,microscopy,photography,and spectroscopy.

Entropy-driven strand displacement reaction for ultrasensitive detection of circulating tumor DNA based on upconversion and Fe_(3)O_(4) nanocrystals

Early detection of cancer biomarkers applied in real-time disease diagnosis and therapies can increase the survival rate of patients.Circulating tumor DNA(ct DNA)as a typical cancer biomarker plays a great role in the process of tumor disease monitoring,especially in early diagnosis.Unfortunately,most ct DNA detection systems have not been widely used due to their low sensitivity,poor specificity,and high cost.Herein,we developed an alternative ct DNA detection system to present the levels of ct DNA by recording the fluorescence signals of the system containing upconversion nanoparticles(UCNPs),Fe_(3)O_(4),and entropy-driven strand displacement reaction.The method has a practical sensitivity with a wide linear range from 100 amol L^(-1)to 1 nmol L^(-1)and a low detection limit of 1.6 amol L^(-1).Furthermore,the system demonstrates a practical application in mouse blood serum samples and meets the requirements for rapid,sensitive,specific,and economical diagnosis of cancers.Thus,this ct DNA detection system may have great potential for ct DNAdetection and clinical diagnosis.