In situ monitoring of loading and elution processes of cryoprotectants at the single-cell level with Raman spectroscopy.

Background: The analysis of cell membrane permeability plays a crucial role in improving the procedures of cell cryopreservation, which will affect the specific parameter settings in loading, removal and cooling processes. However, existing studies have mostly focused on deriving permeability parameters through osmotic theoretical models and cell volume response analysis, and there is still a lack of the direct experimental evidence and analysis at the single-cell level regarding the migration of cryoprotectants.

Results: In this work, a side perfusion microfluidics chips combined with Raman spectroscopy system was built to monitor in situ the Raman spectroscopy of extracellular and intracellular solution during loading and elution process with different cryoprotectant solution systems (single and dual component).

Design method for engineering the initial structure of a spectrometer.

A well-considered initial structure plays a key role in the design of an exceptional spectrometer. Previously, the design method for the optical initial structure (MOIS) that has only focused on the optical properties based on simple imaging formulas and coma-free conditions has been extensively researched. However, as the shape and size of any optical component are not considered for the MOIS, the optical parameters before and after optimization are very different, which results in a loss of reference value of the initial structure.

Dense Convolutional Neural Network for Identification of Raman Spectra.

The rapid development of cloud computing and deep learning makes the intelligent modes of applications widespread in various fields. The identification of Raman spectra can be realized in the cloud, due to its powerful computing, abundant spectral databases and advanced algorithms. Thus, it can reduce the dependence on the performance of the terminal instruments.

A study on the relationship between the crystallization characteristics of quenched droplets and the effect of cell cryopreservation with Raman spectroscopy.

The cryopreservation method of microdroplets has steadily become widely employed in the cryopreservation of microscale biological samples such as various types of cells due to its fast cooling rate, significant reduction of the concentration of cryoprotectants, and practical liquid handling method. However, it is still necessary to consider the corresponding relationship between droplet size and concentration and the impact of crystallization during the cooling process on cell viability. The key may be a misunderstanding of the influencing factors of crystallization and vitrification behavior with concentration during cooling on the ultimate cell viability, which may be attributable to the inability to analyze the freezing state inside the microdroplets.

Polarization-modulated broadband achromatic bifunctional metasurface in the visible light.

Achromatic bifunctional metasurface is of great significance in optical path miniaturization among advanced integrated optical systems. However, the reported achromatic metalenses mostly utilize a phase compensate scheme, which uses geometric phase to realize the functionality and uses transmission phase to compensate the chromatic aberration. In the phase compensation scheme, all the modulation freedoms of a nanofin are driven at the same time.

Perfect vortex beam with polarization-rotated functionality based on single-layer geometric-phase metasurface.

Perfect vortex (PV) beam has seen significant advances in fields like particle manipulation, optical tweezers, and particle trapping, due to the fact that its ring radius is independent of the topological charge. Although geometric-phase metasurfaces have been proposed to generate PV beams, it always relies on circularly or elliptically polarized incident light, which hinders the miniaturization of compact optical devices. Here, using orthogonal decomposition of polarization vectors (ODPV), we proposed a geometric-phase metasurface, which breaks the dependence of circular polarization, to generate PV beam.

Anatomical characteristics and potential gene mutation sites of a familial recurrent patellar dislocation.

Background: Recurrent patellar dislocation is the result of anatomical alignment and imbalance of restraint of bone and soft tissue. We investigate the anatomical characteristics of the knee joint in a family of patients with recurrent patella dislocation, and to screen the possible pathogenic genes in this family by whole exome sequencing in 4 patients and 4 healthy subjects, so as to provide theoretical basis for the pathogenesis of this disease.

Methods: The data related to patella dislocation were measured by imaging data.

Broadband achromatic longitudinal bifocal metalens in the visible range based on a single nanofin unit cell.

Metasurfaces provide a remarkable platform to manipulate over phase, amplitude, and polarization flexibly and precisely. Bifocal metalens draws great research interest due to its ability of converging wavefronts to different focal positions horizontally and longitudinally. However, as wavelength of incident light changes, chromatic aberration will cause the focal lengths reliance on the incident wavelength, which will affect the performance of metasurface, especially for longitudinal bifocal metalens.

Deeply-recursive convolutional neural network for Raman spectra identification.

Raman spectroscopy has been widely used in various fields due to its unique and superior properties. For achieving high spectral identification speeds and high accuracy, machine learning methods have found many applications in this area, with convolutional neural network-based methods showing great advantages. In this study, we propose a Raman spectral identification method using a deeply-recursive convolutional neural network (DRCNN).

Occlusion disparity refinement for stereo matching through the geometric prior-based adaptive label search.

In stereo matching, occlusion disparity refinement is one of the challenges when attempting to improve disparity accuracy. In order to refine the disparity in occluded regions, a geometric prior guided adaptive label search method and sequential disparity filling strategy are proposed. In our method, considering the scene structural correlation between pixels, the geometric prior information such as image patch similarity, matching distance, and disparity constraint is used in the proposed label search energy function and the disparity labels are searched by superpixel matching.

Automated material identification with a Raman spectrometer based on the contribution enhancement of small differences and the adaptive target Raman peak subtraction.

There is only a small difference in Raman peaks between two materials, but they also represent different molecular materials. Therefore, the accurate identification ability for similar materials with small differences among their Raman peaks plays a key role in Raman spectrometers for material identification. However, the noises, the baseline (i.

Orbit-induced localized spin angular momentum of vector circular Airy vortex beam in the paraxial regime.

We theoretically study the propagation properties of the vector circular Airy vortex beam in detail. The results show that the orbital angular momentum can induce a localized spin angular momentum after autofocusing in the paraxial regime, which leads to an abrupt polarization transition just before the focal plane. However, there is no angular momentum conversion from orbital angular momentum to spin angular momentum during the whole propagation process.

Polarization-controllable perfect vortex beam by a dielectric metasurface.

A perfect vortex beam has been attracting tremendous attention due to the fact that its ring radius is independent of the topological charge. Taking advantage of the superposition principle of phase in Fourier space, we proposed to generate perfect vortex beam using propagation-phase-based dielectric metasurface, which exhibits production efficiency larger than 83.5%.

Snell-like and Fresnel-like formulas of the dual-phase-gradient metasurface.

By patterning the metasurface of two phase gradients that are both space-orthogonal and polarization-orthogonal, we derived the three-dimensional (3D) Snell-like formula and the Fresnel-like formula of the proposed metasurface. Theoretically, the dual-phase-gradient metasurface resembles biaxial-like birefringence, i.e.

Correction for color artifacts using the RGB intersection and the weighted bilinear interpolation.

Due to the defects of optical systems, image sensors, and imperfect algorithms for image acquisition, compression, and restoration, color artifacts often appear in images obtained by imaging devices such as digital cameras and scanners. Moreover, color artifacts are difficult to eliminate because of technical limitations, even in some mature commercial cameras. On the basis of red, green, and blue (RGB) intersection (RGBI), a correction method for color artifacts is proposed in this paper, where the RGB intersection-based method can effectively detect various types of color artifacts.

Broadband achromatic metalens in terahertz regime.

Achromatic focusing is essential for broadband operation, which has recently been realised from visible to infrared wavelengths using a metasurface. Similarly, multi-terahertz functional devices can be encoded in a desired metasurface phase profile. However, metalenses suffer from larger chromatic aberrations because of the intrinsic dispersion of each unit element.

Dielectric longitudinal bifocal metalens with adjustable intensity and high focusing efficiency: erratum.

A number of erratums are presented to correct the inadvertent typing mistakes in our paper.

Monitoring algorithm of tilt angle based on sub-block plane fitting for high-resolution imaging.

The limitation of mechanical structure and misoperations can result in a small tilt angle formed by the sample and the focal plane, which will decrease the resolution of the imaging system. Moreover, the small tilt angle is difficult to be observed. In order to solve this problem, a monitoring algorithm of tilt angle based on sub-block plane fitting for high-resolution imaging systems has been proposed, which is used to measure the initial angle of most 2D samples before imaging and assist users to determine the tilt degree of the sample.

Dielectric longitudinal bifocal metalens with adjustable intensity and high focusing efficiency.

Metalens recently attracts enormous attention due to its microscale figure and versatile functionalities. With the combination of geometric phase and propagation phase, we first wrote the phase equation of bifocal metalens that can high efficiently focus incidence into one or two foci in tandem along longitudinal direction, depending on the polarization of incidence. More importantly, the relative intensity of the two foci can be modulated conveniently by changing the ellipticity of incidence, which is different from previous bifocal metalenses need to be repatterned for each kind of relative intensity [Opt.

Free-space creation of ultralong anti-diffracting beam with multiple energy oscillations adjusted using optical pen.

A light beam propagating over an infinite anti-diffracting distance requires infinite power to preserve its shape. However, the fundamental barrier of finite power in free space has made the problem of diffraction insurmountable in recent decades. To overcome this limitation, we report an approach that employs the multiple energy oscillation mechanism, thereby permitting the creation of a light beam with an ultralong anti-diffracting distance in free space.

Dispersion engineering in unidirectional excitation of the surface wave of photonic crystal.

The discovery of transverse spin angular momentum (SAM) of evanescent and guided modes presents a novel spin-orbit interaction (SOI), i.e., transverse SOI, to affect and control the intensity distribution and propagation path of light.

[Mechanical properties and effect on osteodifferentiation of induced pluripotent stem cells of chitosan/whisker/calcium phosphate cement composite biomaterial].

Objective: To investigate the mechanical properties of the novel compound calcium phosphate cement (CPC) biological material as well as the biological activity and osteogenesis effects of induced pluripotent stem cells (iPS) seeding on scaffold and compare their bone regeneration efficacy in cranial defects in rats.

Methods: Ac- cording to the different scaffold materials, the experiment was divided into 4 groups: pure CPC scaffold group (group A), CPC∶10% chitosan as 2∶1 ratio mixed scaffold group (group B), CPC∶10% chitosan∶whisker as 2∶1∶1 ratio mixed scaffold group (group C), and CPC∶10% chitosan∶whisker as 2∶1∶2 ratio mixed scaffold group (group D). Mechanical properties (bending strength, work-of-fracture, hardness, and modulus of elasticity) of each scaffold were detected.

Value of procalcitonin for diagnosing perioperative pneumonia, urinary infections and superficial surgical site infections in patients undergoing primary hip and knee arthroplasty.

Serum procalcitonin (PCT) levels may be helpful for the diagnosis of infections during the perioperative period of arthroplasty. However, there is much debate in the literature regarding the appropriate cut-off value for different types of surgery and local bacterial infection. The present study aimed to evaluate serum PCT levels in patients undergoing arthroplasty and to determine the cut-off value that may represent perioperative pneumonia, urinary infections and superficial surgical site infections.

Right- and left-handed rules on the transverse spin angular momentum of a surface wave of photonic crystal.

By investigating the surface wave of photonic crystal, we put forward two sets of rules: the right-handed screw rule, judging the transverse spin angular momentum (SAM) directions according to the propagation direction of the surface wave; and the left-handed rule, judging the excitation direction of the surface wave in accordance to the SAM direction of incident circularly polarized light and the relative position of the dipole-like scatterer with respect to the interface where the surface wave propagates. Both right- and left-handed rules apply to the interface consisting of opposite-sign-permittivity materials. With the help of these two sets of rules, it is convenient to judge the direction of the transverse SAM and the excited surface wave, which facilitate the application involving transverse SAM of the surface wave.

Parameter determination and transformation for the focusing of dielectric microspheres illuminated by optical needle.

By eliminating the spherical aberrations of microsphere we derived a simple but useful formula on the focusing of dielectric microsphere. On basis of this formula, not only can researchers determine the parameters of an optical microsphere system with super-resolution, but they can also perform parameter transformation. In order to facilitate the application, the principle of parameter transformation was summarized into three kinds of case listed in Table 1, which were all demonstrated numerically with concrete examples by finite-difference time-domain method.