Accuracy study of a binocular-stereo-vision-based navigation robot for minimally invasive interventional procedures

BACKGROUND Medical robot is a promising surgical tool,but no specific one has been designed for interventional treatment of chronic pain.We developed a computed tomography-image based navigation robot using a new registration method with binocular vision.This kind of robot is appropriate for minimal invasive interventional procedures and easy to operate.The feasibility,accuracy and stability of this new robot need to be tested.AIM To assess quantitatively the feasibility,accuracy and stability of the binocularstereo-vision-based navigation robot for minimally invasive interventional procedures.METHODS A box model was designed for assessing the accuracy for targets at different distances.Nine(three sets)lead spheres were embedded in the model as puncture goals.The entry-to-target distances were set 50 mm(short-distance),100 mm(medium-distance)and 150 mm(long-distance).Puncture procedure was repeated three times for each goal.The Euclidian error of each puncture was calculated and statistically analyzed.Three head phantoms were used to explore the clinical feasibility and stability.Three independent operators conducted foramen ovale placement on head phantoms(both sides)by freehand or under the guidance of robot(18 punctures with each method).The operation time,adjustment time and one-time success rate were recorded,and the two guidancemethods were compared.RESULTS On the box model,the mean puncture errors of navigation robot were 1.7±0.9 mm for the short-distance target,2.4±1.0 mm for the moderate target and 4.4±1.4 mm for the long-distance target.On the head phantom,no obvious differences in operation time and adjustment time were found among the three performers(P>0.05).The median adjustment time was significantly less under the guidance of the robot than under free hand.The one-time success rate was significantly higher with the robot(P<0.05).There was no obvious difference in operation time between the two methods(P>0.05).CONCLUSION In the laboratory environment,accuracy of binocular-stereo-vision-based navigation robot is acceptable for target at 100 mm depth or less.Compared with freehand,foramen ovale placement accuracy can be improved with robot guidance.

Dynamic performance of a long-stroke fast tool servo system

A fast tool servo(FTS)system can be used to efficiently manufacture optical freeform surfaces.This paper investigates the dynamic performance of an FTS system driven by a voice coil motor and guided by air bearings.A simulation model and testing platform are developed to evaluate the load capacity and stiffness of the air bearings.The mechanical dynamic performance of the designed FTS,including modal and harmonic analyses,is assessed using finite element analysis.A nonlinear relation between air-bearing stiffness and mechanical bandwidth is obtained.The working dynamic performance is tested through system runout,tracking performance,and closed-loop tests.Quantitative relations between air-bearing stiffness and the mechanical and working bandwidths are established and analyzed.Machining experiments verify the feasibility of the FTS system with 31.05 N/μm stiffness air-bearings.

Armoring Black Phosphorus Anode with Stable Metal–Organic‑Framework Layer for Hybrid K‑Ion Capacitors

Potassium-ion capacitors(KICs)are promising for sustainable and eco-friendly energy storage technologies,yet their slow reaction kinetics and poor cyclability induced by large K-ion size are a major obstacle toward practical applications.Herein,by employing black phosphorus nanosheets(BPNSs)as a typical high-capacity anode material,we report that BPNS anodes armored with an ultrathin oriented-grown metal–organic-framework(MOF)interphase layer(BPNS@MOF)exhibit regulated potassium storage behavior for highperformance KICs.The MOF interphase layers as protective layer with ordered pores and high chemical/mechanical stability facilitate K ion diffusion and accommodate the volume change of electrode,beneficial for improved reaction kinetics and enhanced cyclability,as evidenced by substantial characterizations,kinetics analysis and DFT calculations.Consequently,the BPNS@MOF electrode as KIC anodes exhibits outstanding cycle performance outperforming most of the reported state-of-art KICs so far.

Fabrication of wear-resistant PA6 composites with superior thermal conductivity and mechanical properties via constructing highly oriented hybrid network of SiC-packed BN platelets

Herein,a strong extensional and shearing field was introduced to construct highly oriented hybrid networks of silicon carbide(SiC)-packed boron nitride(BN)platelets to fabricate high-performance wearresistant PA6 composites.Results show that in-plane and through-plane thermal conductivity(TC)of the prepared PA6 composites with a total filler loading of 20 wt.%reached 1.31 and 0.35 W/(m K),352%and 25%higher than those of pure PA6,respectively.It is attributed to the highly oriented hybrid network that facilitates the formation of efficient thermal conductivity pathways.Temperature monitoring results during friction confirm that high TC favors the friction heat dissipation performance.Meanwhile,the yield strength of PA6 composites increased by 39.1%and they still have excellent ductility with an elongation at break of 207.1%.Finally,the wear rate of PA6 composites decreased sharply by 92.5%.This method can be used to manufacture advanced linear bearing and guideway parts,etc。

Whole-brain Optical Imaging:A Powerful Tool for Precise Brain Mapping at the Mesoscopic Level

The mammalian brain is a highly complex network that consists of millions to billions of densely-interconnected neurons.Precise dissection of neural circuits at the mesoscopic level can provide important structural information for understanding the brain.Optical approaches can achieve submicron lateral resolution and achieve“optical sectioning”by a variety of means,which has the natural advantage of allowing the observation of neural circuits at the mesoscopic level.Automated whole-brain optical imaging methods based on tissue clearing or histological sectioning surpass the limitation of optical imaging depth in biological tissues and can provide delicate structural information in a large volume of tissues.Combined with various fluorescent labeling techniques,whole-brain optical imaging methods have shown great potential in the brain-wide quantitative profiling of cells,circuits,and blood vessels.In this review,we summarize the principles and implementations of various whole-brain optical imaging methods and provide some concepts regarding their future development.

Ultrasensitive and point-of-care detection of plasma phosphorylated tau in Alzheimer’s disease using colorimetric and surface-enhanced Raman scattering dual-readout lateral flow assay

Phosphorylation of tau at Ser(396,404)(p-tau^(396,404))is one of the earliest phosphorylation events,plasma p-tau^(396,404) level appears to be a potentially promising biomarker of Alzheimer’s disease(AD).The low abundance and easy degradation of p-tau in the plasma make the lateral flow assay(LFA)a suitable choice for point-of-care detection of plasma p-tau^(396,404) levels.Herein,based on our screening of a pair of p-tau^(396,404)-specific antibodies,we developed a colorimetric and surface-enhanced Raman scattering(SERS)dual-readout LFA for the rapid,highly sensitive,robust detection of plasma p-tau^(396,404) levels.This LFA realized a detection limit of 60 pg/mL by the naked eye or 3.8 pg/mL by SERS without cross-reacting with other tau species.More importantly,LFA rapidly and accurately differentiated AD patients from healthy controls,suggesting that it has the potential for clinical point-of-care application in AD diagnosis.This dual-readout LFA has the advantages of simple operation,rapid,ultra-sensitive detection,providing a new way for early AD diagnosis and intervention,especially in primary and community AD screening.

Liquid crystal integrated metalens with tunable chromatic aberration

Overcoming chromatic aberrations is a vital concern in imaging systems in order to facilitate fullcolor and hyperspectral imaging.By contrast,large dispersion holds opportunities for spectroscopy and tomography.Combining both functions into a single component will significantly enhance its versatility.A strategy is proposed to delicately integrate two lenses with a static resonant phase and a switchable geometric phase separately.The former is a metasurface lens with a linear phase dispersion.The latter is composed of liquid crystals(LCs)with space-variant orientations with a phase profile that is frequency independent.By this means,a broadband achromatic focusing from 0.9 to 1.4 THz is revealed.When a saturated bias is applied on LCs,the geometric phase modulation vanishes,leaving only the resonant phase of the metalens.Correspondingly,the device changes from achromatic to dispersive.Furthermore,a metadeflector with tunable dispersion is demonstrated to verify the universality of the proposed method.Our work may pave a way toward active metaoptics,promoting various imaging applications.

Organic heterostructures composed of one-and two-dimensional polymorphs for photonic applications

Organic heterostructures(OHSs)consist of organic micro/nanocrystals are of essential importance for the construction of integrated optoelectronics in the future.However,the scarcity of materials and the problem of phase separation still hinder the fine synthesis of OHSs.Herein,based on theαphase one-dimensional(1D)microrods and theβphase 2D microplates of one organic compound 3,3′-((1 E,1′E)-anthracene-9,10-diylbis(ethane-2,1-diyl))dibenzonitril(m-B2BCB),we facilely synthesized the OHSs composed of these two polymorph phases,whose growth mechanism is attributed to the low lattice mismatch rate of5.8%between(001)plane ofαphase(trunk)and(010)crystal plane ofβphase(branch).Significantly,the multiport in/output channels can be achieved in the OHSs,which demonstrates the structure-dependent optical signals with the different output channels in the OHSs.Therefore,our experiment exhibits the great prospect of polymorphism in OHSs,which could provide further applications on multifunctional organic integrated photonics circuits.

Flexible self-charging power units for portable electronics based on folded carbon paper

The urgent demand for portable electronics has promoted the development of high-efficienc）9 sustainable, and even stretchable self-charging power sources. In this work, we propose a flexible self-charging power unit based on folded carbon （FC） paper for harvesting mechanical energy from human motion and power portable electronics. The present unit mainly consists of a triboelectric nanogenerator （FC-TENG） and a supercapacitor （FC-SC）, both based on folded carbon paper, as energy harvester and storage device, respectively. This favorable geometric design provides the high Young＇s modulus carbon paper with excellent stretchability and enables the power unit to work even under severe deformations, such as bending, twisting, and rolling. In addition, the tensile strain can be maximized by tuning the folding angle of the triangle-folded carbon paper. Moreover, the waterproof property of the packaged device make it washable, protect it from human sweat, and enable it to work in harsh environments. Finally, the as-prepared self-charging power unit was tested by placing it on the human body to harvest mechanical energy from hand tapping, foot treading, and arm touching, successfully powering an electronic watch. This work demonstrates the impressive potential of stretchable self-charging power units, which will further promote the development of high Young＇s modulus materials for wearable/portable electronics.

Structure evolution,dielectric,and conductivity behavior of(K_(0.5)Na_(0.5))NbO_(3)-Bi(Zn_(2/3)Nb_(1/3))O_(3) ceramics

(1-x)K_(0.5)Na_(0.5)Nb0_(3-x)Bi(Zn_(2/3)Nb_(1/3))0_(3)((1-x)KNN-xBZN,x=0.010,0.015,0.020,0.025,and 0.030)lead-free ceramics were fabricated via a traditional solid-state method.The crystal structure,microstructure,dielectric,and conductivity behavior of this system were studied.Combined with X-ray diffraction(XRD)patterns,Rietveld refinement,and dielectric spectroscopy,an orthorhombic phase was determined for x=0.010,an orthorhombic-tetragonal mixed phase was identified for x=0.015,and a rhombohedral symmetry appears in 0.020≤x≤0.030.Both 0.98KNN-0.02BZN and 0.975KNN-0.025BZN ceramics exhibit stable permittivity and low dielectric loss tangent(tan)in wide temperature ranges owing to the combination of rhombohedral-tetragonal step-like feature and the diffuse phase transition from tetragonal to cubic.The activation energies of dielectric relaxation and conductivity behavior at high temperatures initially decrease slightly,then drop sharply,and finally decline slowly,which could be attributed to microstructure morphologies and the concentration of oxygen vacancies.

Super-Stacking Self-Assembly of Organic Topological Heterostructures

The precise control of multicomponent complex topological configurations integrating more than one compound or one crystal phase with high spatial and angular precision is extremely challenging due to anisotropic noncovalent interaction and undesirable phase separation.Herein,we present a superstacking self-assembly approach via noncovalent interaction strength(|EBGP-TCNB(−3.14 kcal mol−1)|>|EBGP-TFP(−2.84 kcal mol−1)|>|EBGP-OFN(−2.15 kcal mol−1)|>|EBGP(−1.33 kcal mol−1)|)adjustment for the fine synthesis of molecular heterostructures with various photophysical properties and lowdimensional morphologies,as well as phase heterostructures with multifunctional optoelectrical characteristics and multidimensional morphologies.Notably,the anisotropic noncovalent interaction and lattice matching principle facilitate the sequential crystallization and horizontal/longitudinal growth in the crystal-puzzle process,respectively.This super-stacking self-assembly approach is amenable to precise design and fine synthesis of desirable organic multicomponent complex topological configurations for integrated optoelectronics.

Templated spherical coassembly strategy to fabricate MoS_(2)/C hollow spheres with physical/chemical polysulfides trapping for lithium-sulfur batteries

Rational design of advanced polar hosts with high sulfur loading,facilitated ionic/electronic transport and effectively suppressed shuttling effect has great potential for high performance lithium-sulfur batteries,yet it remains challenging.Here we propose a novel templated spherical coassembly strategy to fabricate the MoS_(2)/C hollow spheres as an efficient sulfur host material.The unique hollow structure provides enough interior space for accommodating a substantial amount of sulfur,and effectively suppresses the diffusion of dissolved polysulfides by both physical confinement and chemical adsorption.Moreover,the ionic transport as well as the ability to mitigate volume variation upon cycling is also improved,thereby maximizing the utilization of sulfur.Owing to these merits,when evaluated as a sulfur host for lithiumsulfur batteries,the MoS_(2)/C hollow spheres exhibit appealing electrochemical performance with an impressive specific capacity of 1082 mA hg^(-1)at 0.1 C,excellent rate capability and superior cycling stability with a low fading rate of 0.04%per cycle.

Spatial donor/acceptor architecture for intramolecular charge-transfer emitter

Charge transfer via electron hopping from an electron donor(D)to an acceptor(A)in nanoscale,plays a crucial role in optoelectronic materials,such as organic light-emitting diodes(OLEDs)and organic photovoltaic cells(OPVs).Here,we propose a strategy for binding D/A units in space,where intramolecular charge-transfer can take place.The resulted material DM-Me-B is able to give bright emission in this molecular architecture because of the good control of D/A interaction and conformational rigidity.Moreover,DM-Me-B presents small singlet-triplet splitting energy,enabling thermally activated delayed fluorescence.Therefore,the DM-Me-B exhibits~20%maximum external quantum efficiency and low efficiency roll-off at 1000 cd/m^(2),certifying an effective strategy in controlling D/A blocks through space.

Visible light-promoted aerobic oxidative cleavage and cyclization of olefins to access 3-hydroxyisoindolinones

A convenient and environmentally friendly synthetic route from 2-vinylbenzimide to 3-hydroxy-isoindolinones through visible light-promoted transformations via iron/disulfide catalysis and molecular oxygen oxidation has been developed.A range of 3-hydroxy-isoindolinones was obtained in moderate to good yields,which exhibit excellent functional group compatibility and broad substrate scope.Further mechanistic investigations proved that dioxetane might be a key intermediate being involved in the reaction.