Engineering personalized neural tissue using functionalized transcription factors

Diseases and disorders of the central nervous system often require significant interventions to restore lost function due to their com- plexity. Examples of such disorders include Parkinson＇s disease, Alzheimer＇s disease, multiple sclerosis, traumatic brain injury, and spinal cord in）ury. These diseases and disorders result trom healthy cells being destroyed, which in turn causes dysfunction in the cen- tral nervous system, The death of these cells can trigger a cascade of events that affect the rest of the body, causing symptoms that become progressively worse over time. Developing strategies for repairing the damage to the central nervous system remains chal- lenging, in part due to its inability to regenerate.

Functional engineering strategies of 3D printed implants for hard tissue replacement

Three-dimensional printing technology with the rapid development of printing materials are widely recognized as a promising way to fabricate bioartificial bone tissues.In consideration of the disadvantages of bone substitutes,including poor mechanical properties,lack of vascularization and insufficient osteointegration,functional modification strategies can provide multiple functions and desired characteristics of printing materials,enhance their physicochemical and biological properties in bone tissue engineering.Thus,this review focuses on the advances of functional engineering strategies for 3D printed biomaterials in hard tissue replacement.It is structured as introducing 3D printing technologies,properties of printing materials(metals,ceramics and polymers)and typical functional engineering strategies utilized in the application of bone,cartilage and joint regeneration.

Work function engineering to enhance open-circuit voltage in planar perovskite solar cells by g-C_(3)N_(4) nanosheets

Enhancement of open-circuit voltage(Voc)is an effective way to improve power conversion efficiency(PCE)of the perovskite solar cells(PSCs).Theoretically,work function engineering of TiO2 electron transport layer can reduce both the loss of Voc and current hysteresis in PSCs.In this work,two-dimensional g-C_(3)N_(4) nanosheets were adopted to modify the compact TiO2 layers in planar PSCs,which can finely tune the work function(WF)and further improve the energy level alignment at the interface to enhance the Voc and diminish the hysteresis.Meanwhile,the quality of perovskite films and charge transfer of the devices were improved by g-C_(3)N_(4) nanosheets.Therefore,the PCE of the planar PSCs was champed to 19.55%without obvious hysteresis compared with the initial 15.81%,mainly owing to the remarkable improvement of VOC from 1.01 to 1.11 V.In addition,the stability of the devices was obviously improved.The results demonstrate an effective strategy of W_(F) engineering to enhance Voc and diminish hysteresis phenomenon for improving the performance of PSCs.

Resolution and contrast enhancements of optical microscope based on point spread function engineering

Point spread function （PSF） engineering-based methods to enhance resolution and contrast of optical microscopes have experienced great achievements in the last decades. These techniques include： stimulated emis- sion depletion （STED）, time-gated STED （g-STED）, ground-state depletion microscopy （GSD）, difference confocal microscopy, fluorescence emission difference microscopy （FED）, switching laser mode （SLAM）, virtual adaptable aperture system （VAAS）, etc. Each affords unique strengths in resolution, contrast, speed and expenses. We explored how PSF engineering generally could be used to break the diffraction limitation, and concluded that the common target of PSF engineering- based methods is to get a sharper PSF. According to their common or distinctive principles to reshape the PSF, we divided all these methods into three categories, nonlinear PSF engineering, linear PSF engineering, and linear-based nonlinear PSF engineering and expounded these methods in classification. Nonlinear effect and linear subtraction is the core techniques described in this paper from the perspective of PSF reconstruction. By comparison, we emphasized each method＇s strengths, weaknesses and biologic applications. In the end, we promote an expecta- tion of prospective developing trend for PSF engineering.

The Expanding Analysis of Enterprise＇s Human Capital Investment Value

Value is the scale that appraises whether the comparison between a certain thing and its realization which we need to consume is rational. The paper appraises the investment value and incomes of human capital by applying value engineering method. It elaborates the investment structure and contents of human capital first, and then analyzes and summarizes various functions of enterprise＇s human capital. It educes the production function and the optimum equilibrium solution of human capital on this basis. Finally, it appraises the investment value of human capital by applying VE method. Thus we will apply a new method in the human capital field.

Three-Dimensional Sub-100 nm Super-Resolution Imaging of Biological Samples Using a Phase Ramp in the Objective Pupil

Localisation microscopy overcomes the diffraction limit by measuring the position of individual molecules to obtain optical images with a lateral resolution better than 30 nm. Single molecule localisation microscopy was originally demonstrated only in two dimensions but has recently been extended to three dimensions. Here we develop a new approach to three-dimensional （3D） localisation microscopy by engineering of the point-spread function （PSF） of a fluorescence microscope. By introducing a linear phase gradient between the two halves of the objective pupil plane the PSF is split into two lateral lobes whose relative position depends on defocus. Calculations suggested that the phase gradient resulting from the very small tolerances in parallelism of conventional slides made from float glass would be sufficient to generate a two-lobed PSF. We demonstrate that insertion of a suitably chosen microscope slide that occupies half the objective aperture combined with a novel fast fitting algorithm for 3D localisation estimation allows nanoscopic imaging with detail resolution well below 100 nm in all three dimensions （standard deviations of 20, 16, and 42 nm in x, y, and z directions, respectively）. The utility of the approach is shown by imaging the complex 3D distribution of microtubules in cardiac muscle cells that were stained with conventional near infrared fluorochromes. The straightforward optical setup, minimal hardware requirements and large axial localisation range make this approach suitable for many nanoscopic imaging applications.

Dielectric metasurfaces for distance measurements and three-dimensional imaging

Ultrathin metasurfaces have shown the capability to influence all aspects of light propagation.This has made them promising options for replacing conventional bulky imaging optics while adding advantageous optical properties or functionalities.We demonstrate that such metasurfaces can also be applied for single-lens three-dimensional(3-D)imaging based on a specifically engineered point-spread function(PSF).Using Huygens’metasurfaces with high transmission,we design and realize a phase mask that implements a rotating PSF for 3-D imaging.We experimentally characterize the properties of the realized double-helix PSF,finding that it can uniquely encode object distances within a wide range.Furthermore,we experimentally demonstrate wide-field depth retrieval within a 3-D scene,showing the suitability of metasurfaces to realize optics for 3-D imaging,using just a single camera and lens system.

Strain effect on the electronic properties of III-nitride nanosheets:Ab-initio study

In this study the structural and electronic properties of III-nitride monolayers XN(X=B, Al, Ga and In) under different percentages of homogeneous and shear strain are investigated using the full potential linearized augmented plane wave within the density functional theory. Geometry optimizations indicate that GaN and InN monolayers get buckled under compressive strain.Our calculations show that the free-strains of these four monolayers have an indirect band gap. By applying compressive biaxial strain, a transition from indirect to direct band gap occurs for GaN and InN, while the character of band gap for BN and AlN is not changed. Under tensile strain, only BN monolayer behaves as direct band gap semiconductor. In addition, when the shear strain is applied, only InN undergoes an indirect to direct band gap transition. Furthermore, the variations of band gap versus strain for III-nitride monolayers have been calculated. When a homogeneous uniform strain, in the range of [.10%, +10%], is applied to the monolayers, the band gap can be tuned for from 3.92 eV to 4.58 eV for BN, from 1.67 eV to 3.46 eV for AlN, from0.24 eV to 2.79 eV for GaN and from 0.60 eV to 0.90 eV for InN.