Selective Ring-Opening Polymerization of Silyl Glycidyl Ether through Organocatalysis.

Silyl ether constitutes a multipurpose (macro)molecular functionality for being, e.g., SuFEx-clickable and easily cleavable as a hydroxyl precursor. Its direct incorporation by anionic polymerization is challenged by its base susceptibility. In this study, a two-component organocatalyst shows strict epoxy-selectivity in the anionic ring-opening polymerization (ROP) of commercially available tert-butyldimethylsilyl (R)-(-)-glycidyl ether (TBSGE). The silyl ether pendant groups are fully preserved in the resultant polyether and readily undergo acidic hydrolysis to yield well-defined linear polyglycerol (PGC). Combination of the ROP with mechanistically distinct polymerization chemistries delivers PGC-based polyurethane and a hybrid amphiphilic block copolymer. The SuFEx reaction with sulfonyl fluoride shows effective tuning of polyTBSGE into a sulfonate-functionalized polyether. We have thus exploited the chemoselectivity of organocatalysis to facilitate access to polymers carrying reactive pendant functionalities.

Design of a refractive-metasurface hybrid annular aperture folded optical system.

Folded lenses offer advantages in terms of lightness and thinness, but they have limitations when it comes to correcting aberrations. In this paper, we propose a novel approach to address this issue by incorporating metasurfaces in the design of folded optical systems. Specifically, a folded refractive-metasurface hybrid annular aperture folded lens (AFL) is introduced. The structural characteristics of the AFL imaging system are analyzed to investigate the blocking ratio, thickness, and light collection capability of the ring aperture system. Additionally, a hybrid optical integration design using Zemax software is proposed for the metasurfaces. A quadruple-folded AFL working in the mid-infrared waveband is then designed. The superstructure surface is analyzed, and its processability is discussed. The results demonstrate that the reflective-metasurface hybrid AFL significantly improves the imaging quality of this type of optical system while meeting the required design accuracy.

A Three-Dimensional Deformation Monitoring Method: Combining Optical Deformation Monitoring Based on Regression Models and GB-SAR Interferometry.

This paper introduces a method for quantifying the three-dimensional deformation of ground targets and outlines the associated process. Initially, ground-based synthetic aperture radar was employed to monitor the radial deformation of targets, and optical equipment monitored pixel-level deformation in the vertical plane of the line of sight. Subsequently, a regression model was established to transform pixel-level deformation into two-dimensional deformation based on a fundamental length unit, and the radar deformation monitoring data were merged with the optical deformation monitoring data. Finally, the fused data underwent deformation, resulting in a comprehensive three-dimensional deformation profile of the target. Through physical data acquisition experiments, the comprehensive three-dimensional deformation of targets was obtained and compared with the actual deformations. The experimental results show that the method has a relative error of less than 10%, and monitoring accuracy is achieved at the millimeter level.

Nanoscaled Titanium Oxide Layer Provokes Quick Osseointegration on 3D-Printed Dental Implants: A Domino Effect Induced by Hydrophilic Surface.

Three-dimensional printing is a revolutionary strategy to fabricate dental implants. Especially, 3D-printed dental implants modified with nanoscaled titanium oxide layer (H-SLM) have impressively shown quick osseointegration, but the accurate mechanism remains elusive. Herein, we unmask a domino effect that the hydrophilic surface of the H-SLM facilitates blood wetting, enhances the blood shear rate, promotes blood clotting, and changes clot features for quick osseointegration. Combining computational fluid dynamic simulation and biological verification, we find a blood shear rate during blood wetting of the hydrophilic H-SLM 1.2-fold higher than that of the raw 3D-printed implant, which activates blood clot formation. Blood clots formed on the hydrophilic H-SLM demonstrate anti-inflammatory and pro-osteogenesis effects, leading to a 1.5-fold higher bone-to-implant contact and a 1.8-fold higher mechanical anchorage at the early stage of osseointegration. This mechanism deepens current knowledge between osseointegration speed and implant surface characteristics, which is instructive in surface nanoscaled modification of multiple 3D-printed intrabony implants.

Impaired glycosylation of GmPAP15a, a root-associated purple acid phosphatase, inhibits extracellular phytate-P utilization in soybean.

Phosphorus (P) is an essential nutrient, but easily fixed in soils. Therefore, most of soil P exists in the form of inaccessible organic phosphorus (Po), particularly phytate-P. Root-associated purple acid phosphatases (PAPs) are considered to play a crucial role in phosphate (Pi) scavenging in soils. However, evidence for regulating root-associated PAPs in utilization of extracellular phytate-P remain largely unknown in plants at both transcriptional and posttranslational levels. In this study, a Pi-starvation responsive GmPAP15a was identified in soybean (Glycine max). Overexpressing GmPAP15a led to significant increases in root-associated phytase activities, as well as total P content when phytate-P was supplied as the sole P resource in soybean hairy roots. Meanwhile, mass spectrometry (MS) analysis showed GmPAP15a was glycosylated at Asn144 and Asn502 , and its glycan structures of N-linked oligosaccharide chains exhibited microheterogeneity. Moreover, two homologues of AtPHR1, GmPHR9 and GmPHR32 were found to activate GmPAP15a transcription through luciferase activity analysis. Taken together, it is strongly suggested that GmPAP15a plays a vital role in phytate-P utilization in soybean, which might be regulated at both transcriptional and glycosylation modification levels. Our results highlight the GmPHR9/GmPHR32-GmPAP15a signalling pathway might present, and control phytate-P utilization in soybean.

Relationship between machining accuracy and optical properties of convex blazed grating in ultra-precision cutting.

For ultra-precision machining of convex blazed grating elements there are inevitable machining errors, surface defects, and surface roughness, all of which can have an impact on their diffraction efficiency. In this paper, we use PCGrate software based on the integration method to establish the machining error model, surface defect model, and surface roughness model of convex spherical blazed grating with a curvature radius of 41.104 mm, a substrate diameter of 14 mm, a grating density of 53.97 line/mm and a blazed angle of 3.86° as the basic specification. To investigate the effect of base curvature radius error, grating period error, blazed angle error, grating ridge and valley passivation radius, Poisson burr height, and blaze surface roughness on their -1 order diffraction efficiency in the 0.95-2.5 µm spectral range. The results show that when the curvature radius error of the spherical base is less than ±80µm, the influence on diffraction efficiency can be ignored. Among the three groups of grating microstructure parameters, the influence of blazed angle on grating diffraction efficiency is the largest, followed by a grating period, and the influence of grating apex angle is the smallest, among which when the error of blazed angle is less than ±0.1° and the error of grating period is less than ±0.1µm, the influence on diffraction efficiency can be ignored. The effect of the passivation radius of the grating valley on the diffraction efficiency is smaller than that of the passivation radius of the grating ridge, and the maximum reduction of diffraction efficiency is 0.096 and 0.144 when the grating ridge and valley passivation radius are 50nm∼650 nm, respectively. The diffraction efficiency decreases significantly in the wavelength range of 1.9-2.5 µm with the increase of Poisson burr height and blaze surface roughness, and its effect on the diffraction efficiency can be neglected when the Poisson burr height is less than 0.5 µm and the blaze surface roughness value is less than RMS 1 nm. The machining error, surface defect, and surface roughness models of the convex blazed grating are optimized to provide a comprehensive machining accuracy basis for ultra-precision cutting of convex grating components.

Modeling and Experimental Verification of Time-Controlled Grinding Removal Function for Optical Components.

As a flexible grinding method with high efficiency, abrasive belt grinding has been widely used in the machining of mechanical parts. However, abrasive belt grinding has not been well applied in the field of ultra-precision optical processing, due to the lack of a stable and controllable removal function. In this paper, based on the idea of deterministic machining, the time-controlled grinding (TCG) method based on the abrasive belt as a machining tool was applied to the deterministic machining of optical components. Firstly, based on the Preston equation, a theoretical model of the TCG removal function was established. Secondly, removal function experiments were carried out to verify the validity and robustness of the theoretical removal model. Further, theoretical and actual shaping experiments were carried out on 200 mm × 200 mm flat glass-ceramic. The results show that the surface shape error converged from 6.497 µm PV and 1.318 µm RMS to 5.397 µm PV and 1.115 µm RMS. The theoretical and experimental results are consistent. In addition, the surface roughness improved from 271 to 143 nm Ra. The results validate the concept that the removal function model established in this paper can guide the actual shaping experiments of TCG, which is expected to be applied to the deterministic machining of large-diameter optical components.

Nano-Precision Processing of NiP Coating by Magnetorheological Finishing.

NiP coating has excellent physicochemical properties and is one of the best materials for coating optical components. When processing NiP coatings on optical components, single-point diamond turning (SPDT) is generally adopted as the first process. However, SPDT turning produces periodic turning patterns on the workpiece, which impacts the optical performance of the component. Magnetorheological finishing (MRF) is a deterministic sub-aperture polishing process based on computer-controlled optical surface forming that can correct surface shape errors and improve the surface quality of workpieces. This paper analyzes the characteristics of NiP coating and develops a magnetorheological fluid specifically for the processing of NiP coating. Based on the basic Preston principle, a material removal model for the MRF polishing of NiP coating was established, and the MRF manufacturing process was optimized by orthogonal tests. The optimized MRF polishing process quickly removes the SPDT turning tool pattern from the NiP coating surface and corrects surface profile errors. At the same time, the surface quality of the NiP coating has also been improved, with the surface roughness increasing from Ra 2.054 nm for SPDT turning to Ra 0.705 nm.

A prediction model for nanoparticle diffusion behavior in fibrous materials considering steric and hydrodynamic resistances.

Precise prediction of the hindered diffusion behavior of electroneutral particles in fibrous media plays a critical role in the development of drugs, polymer membranes, and porous electrodes. However, the random microstructure and unknown coupling relationship of multiple resistance mechanisms lead to the lack of a universal prediction model. In this work, a dual-resistance model is proposed by reconstructed pore-scale simulations, which presents the coexistence of steric and hydrodynamic resistances in the multiplication form. The simulation results show that the relationship between steric resistance and structural parameters (porosity, fiber radius, and particle radius) is exponential, while that for hydrodynamic resistance is polynomial. The dominant diffusion resistance is found to change from hydrodynamic to steric resistance with a decrease in porosity. The fluorescent polystyrene microsphere diffusivity in a series of SiO2 fibrous media is determined by single-particle tracking experiments, quantitatively confirming the dual-resistance model. The present model can be used for rapid diffusivity prediction and fibrous membrane and drug design.

A Method of Restraining the Adverse Effects of Grinding Marks on Small Aperture Aspheric Mirrors.

The grinding method is used as the preliminary processing procedure for small aperture aspheric mirrors. Regular grinding marks produced in the grinding process significantly affect the mid-spatial frequency error; however, because of their small radius of surface curvatures and high steepness, they are difficult to polish using traditional methods. Therefore, in this study, the ultra-precision grinding and polishing process of fused quartz material was investigated, and the influence of grinding marks was analyzed, which achieved the purpose of restraining the grinding marks in the grinding process. The generation mechanisms of horizontal and vertical grinding marks were analyzed by means of simulation and experiment, and the relationship between different grinding process parameters and surface quality was explored. A magnetorheological finishing (MRF) spot method was used to explore the effects of grinding marks on subsurface damage (SSD). The elastic adaptive polishing method was used to polish an aspheric lens with high steepness and small caliber. Based on the principle of an elastic adaptive polishing mathematical model, the grinding marks were suppressed, and the mid-spatial frequency error of the lens was reduced by optimizing the polishing path and composition of the polishing fluid. The final roughness reached 10 nm Ra. In this paper, the source of wear marks and their influence on the mid-spatial frequency error of small aperture aspheric mirrors are analyzed, and the grinding marks were suppressed by elastic adaptive polishing.

Computational Imaging in Dual-Band Infrared Hybrid Optical System with Wide Temperature Range.

The special dispersion and temperature characteristics of diffractive optical element (DOE) make them widely used in optical systems that require both athermalization and achromatic aberrations designs. The multi-layer DOE (MLDOE) can improve the diffraction efficiency of the overall broad waveband, but its diffraction efficiency decreases with changes in ambient temperature. When the ambient temperature changes, the micro-structure heights of MLDOE and the refractive index of the substrate materials change, ultimately affecting its diffraction efficiency, and, further, the optical transform function (OTF). In this paper, the influence of ambient temperature on the diffraction efficiency of MLDOE in a dual-infrared waveband is proposed and discussed, the diffraction efficiency of MLDOE caused by ambient temperature is derived, and a computational imaging method that combines optical design and image restoration is proposed. Finally, a dual-infrared waveband infrared optical system with athermalization and achromatic aberrations corrected based on computational imaging method is designed. Results show that this method can effectively reduce the diffraction efficiency of MLDOE by ambient temperature and improve the imaging quality of hybrid optical systems.

A High Efficiency and Precision Smoothing Polishing Method for NiP Coating of Metal Mirror.

The NiP coating has excellent wear and corrosion resistance, and electroless nickel-phosphorus coating is one of the best measures for surface modification of metal optical devices. The NiP layer could be processed by single-point diamond turning (SPDT). However, the periodic marks on the surface of the NiP coating processed by SPDT will lead to diffraction and stray light, which will reduce the reflectivity and image quality of the mirror. This paper studied smoothing polishing based on chemical mechanical polishing to remove turning periodic marks efficiently. Firstly, we studied the chemical corrosion and mechanical removal mechanism of smoothing polishing of the NiP coating through theoretical analysis. Then, the influencing factors of processing the quality of smoothing polishing are analyzed, and the optimal machining parameters and polishing slurry formula are formulated. Finally, through the developed process, the surface roughness of Root Mean Square (RMS) 0.223 nm is realized on the NiP coating, and an ultra-smooth surface that can meet the service accuracy of a hard X-ray mirror is obtained. Our research simplifies the high-precision machining process of the NiP coating and improves the machining efficiency. Therefore, it can be used as a new high-precision manufacturing NiP coating method.

Sub-Nanometer Accuracy Combination Processing Technology for Nickel-Phosphorus Modified Surfaces Based on Aluminum Reflector Mirror.

The surface of metal mirrors is often polished by electroless coating with a Ni-P modified layer after single-point diamond turning. In practice, however, improvements in mirror quality are closely related to the polishing environment, polishing medium, and polishing force. If not adequately controlled, processing defects such as visible scratches can lead to the deterioration of surface roughness. Based on the Ni-P modified surface of a metal reflector mirror, this study optimizes the configuration of magnetorheological figuring (MRF) fluid and polishing process parameters so that MRF high-efficiency surface modification can be realized and the scratch problem can be resolved. The processing method of a high-performance metal mirror is developed by studying the high-efficiency and high-precision processing technology based on small head smoothing. The surface roughness achieved by the proposed method was better than Ra = 0.39 nm. The ultrasonic cleaning process effectively improved the surface roughness after processing. According to the combined processing technology developed in this study, the modified layer of the parabolic mirror with a diameter of 370 mm was processed, and the surface quality was increased from RMS = 338.684 nm to RMS = 21.267 nm.

A Green and Facile Microvia Filling Method via Printing and Sintering of Cu-Ag Core-Shell Nano-Microparticles.

In this work, we developed an eco-friendly and facile microvia filling method by using printing and sintering of Cu-Ag core-shell nano-microparticles (Cu@Ag NMPs). Through a chemical reduction reaction in a modified silver ammonia solution with L-His complexing agent, Cu@Ag NMPs with compact and uniform Ag shells, excellent sphericity and oxidation resistance were synthesized. The as-synthesized Cu@Ag NMPs show superior microvia filling properties to Cu nanoparticles (NPs), Ag NPs, and Cu NMPs. By developing a dense refill method, the porosity of the sintered particles within the microvias was significantly reduced from ~30% to ~10%, and the electrical conductivity is increased about twenty-fold. Combing the Cu@Ag NMPs and the dense refill method, the microvias could obtain resistivities as low as 7.0 and 6.3 µΩ·cm under the sintering temperatures of 220 °C and 260 °C, respectively. The material and method in this study possess great potentials in advanced electronic applications.

A Novel Fast Servo Tool Device with Double Piezoelectric Driving.

The fast tool servo (FTS) technology has unique advantages in the machining of complex surfaces such as special-shaped targets and free-form surfaces. In view of the shortcomings in the performance of the existing FTS device, this paper puts forward a novel FTS which uses two piezoelectric ceramics instead of flexure hinges to provide restoring force. Firstly, the feasibility of the double-drive principle is verified theoretically, and the corresponding mechanism is optimized accordingly. Then, the system control hysteresis model is established and identified, and the appropriate control strategy is designed. Finally, the performances of the proposed FTS device are tested, and a typical microstructure is machined based on the device and ultra-precision lathe. The results indicate that the proposed device effectively improves the performance of the FTS system, which is useful for the processing of microstructures and free-form surfaces.

Highly Accurate Digital Processing of Large Stroke Guideway with an Optical Material-Corning Code 7972.

Currently, meter-long guideways rarely achieve an accuracy of dozens of nanometers due to processing difficulties such as the material and the edge effect. In this paper, we focus on this problem and propose a set of optimization processing methods to cope with it. In the grinding stage, a grinding tool is designed to improve the reciprocating processing and address the problem of warping; in the polishing stage, three different processes are compared, and the combination of magnetorheological finishing technology and the polyurethane disc technology process is purposed to reduce the polishing cycle and improve the surface figure accuracy. Moreover, through the combined process of magnetorheological finishing and smoothing, the edge effect and medium- and high-frequency error are essentially suppressed. The meter-long guideway is achieved with an accuracy of dozens of nanometers. Although the sizes of surface A/C and B/D are 1000 mm × 240 mm and 1000 mm × 160 mm, the surface figures are 20.33 nm, 22.78 nm, 39.23 nm and 26.58 nm RMS (Root Mean Square), respectively. The nanometer accuracy guideway is critical to an ultra-precision machine tool. Finally, the X-axis straightness of the profile measurement system formed by the guideway reaches 200 nm/600 mm.

The effect of a diet based on rice straw co-fermented with probiotics and enzymes versus a fresh corn Stover-based diet on the rumen bacterial community and metabolites of beef cattle.

Improvement of the food value of rice straw is urgently required in rice crop growing areas to mitigate pollution caused by rice straw burning and enhance the supply of high-quality forages for ruminants. The aims of the present study were to compare the effects of fresh corn Stover and rice straw co-fermented with probiotics and enzymes on rumen fermentation and establish the feasibility of increasing the rice straw content in ruminant diets and, by extension, reducing air pollution caused by burning rice straw. Twenty Simmental hybrid beef cattle were randomly allotted to two groups with ten cattle per group. They were fed diets based either on rice straw co-fermented with probiotics and enzymes or fresh corn Stover for 90 days. Rumen fluid was sampled with an esophageal tube vacuum pump device from each animal on the mornings of days 30, 60, and 90. Bacterial diversity was evaluated by sequencing the V4-V5 region of the 16S rRNA gene. Metabolomes were analyzed by gas chromatography/time-of-flight mass spectrometry (GC-TOF/MS). Compared to cattle fed fresh corn Stover, those fed rice straw co-fermented with probiotics and enzymes had higher (P < 0.05) levels of acetic acid and propionate in rumen liquid at d 60 and d 90 respectively, higher (P < 0.05) abundances of the phyla Bacteroidetes and Fibrobacteres and the genera Ruminococcus, Saccharofermentans, Pseudobutyrivibrio, Treponema, Lachnoclostridium, and Ruminobacter, and higher (P < 0.05) concentrations of metabolites involved in metabolisms of amino acid, carbohydrate, and cofactors and vitamins. Relative to fresh corn Stover, rice straw co-fermented with probiotics and enzymes resulted in higher VFA concentrations, numbers of complex carbohydrate-decomposing and H2-utilizing bacteria, and feed energy conversion efficiency in the rumen.

Mechanisms of mTOR and Autophagy in Human Endothelial Cell Infected with Dengue Virus-2.

The mechanistic mammalian target of rapamycin (mTOR) plays a crucial role in response to many major cellular processes, including cellular metabolism, proliferation, and autophagy. Both mTOR and autophagy are suggested to be involved in the viral infection. However, little is known about the role of mTOR and autophagy in human endothelial cell infected with dengue virus-2 (DENV-2), this study is to investigate the role of mTOR and autophagy in human umbilical vein endothelial cells (HUVECs) infected with DENV-2 and related regulatory mechanisms. HUVECs were cultured in epithelial cell medium. A series of experiments involving immunohistochemistry, TCID50 method, real-time PCR, western blot, and laser confocal were performed in this study. The cell line was identified as HUVEC by the expression of cell factor VIII. The expression level of DENV-2 mRNA increased and showed an upward trend. Compared with the control group, the fluorescence of autophagy-labeled protein LC3B and lysosome-labeled protein lysosome-associated membrane protein 1 (LAMP1) in the cytoplasm of HUVEC induced by rapamycin was observed, and intensity was significantly enhanced under confocal laser scanning microscope, after fluorescence synthesis, the fluorescence of autophagy-labeled protein LC3B and lysosome-labeled protein LAMP1 overlaps were reduced. The intensity of fluorescence of autophagy-labeled protein LC3B and lysosome-labeled protein LAMP1 increased in 1 × 104 TCID50 DENV-2 infection group, after fluorescence synthesis, fluorescence of autophagy-labeled protein LC3B, lysosome-labeled protein LAMP1, and DEN2 NS1 overlapped. Compared with the control group, the phosphorylation level of mTOR, Atg13, and p-ULK1 in DENV-2-infected group or Rapa treatment group decreased significantly (p < 0.05), and the level of LC3-II increased significantly (p < 0.05). These results suggest that DENV-2 induces autophagy in HUVECs through mTOR signaling molecule.

Influence of ad Libitum Feeding of Piglets With Bacillus Subtilis Fermented Liquid Feed on Gut Flora, Luminal Contents and Health.

Some scholars caution that long-term ad libitum feeding with probiotic fermented food poses potential health risks to baby animals. We conducted a feeding experiment to investigate the influence of ad libitum feeding of pre-and post-weaned piglets with a Bacillus subtilis fermented diet on the gut microbiome, gut metabolomic profiles, bile acid metabolism, proinflammatory cytokines and faecal consistency. Compared with piglets fed a Bacillus subtilis-supplemented pellet diet, piglets fed the Bacillus subtilis fermented liquid diet had lower intestinal bacterial diversity (P > 0.05), higher intestinal fungal diversity (P > 0.05), more Firmicutes (P > 0.05), fewer Bacteroidetes, Actinobacteria and Proteobacteria (P > 0.05), higher concentrations of 3-hydroxypropionic acid (P < 0.05), orotic acid (P < 0.05), interleukin-6 (P < 0.01), lactic acid (P < 0.01), deoxycholic acid (P > 0.05) and lithocholic acid (P < 0.01) and a higher incidence of diarrhoea (P > 0.05). The data show that ad libitum feeding of piglets with a Bacillus subtilis fermented liquid diet during the suckling and early post-weaning periods promotes the growth of lactic acid bacteria, bile salt hydrolase-active bacteria and 7a-dehydroxylase-active bacteria in the intestinal lumen; disturbs the normal production of lactic acid, orotic acid and unconjugated bile acids; and increases circulating interleukin-6 levels and diarrhoea incidence.

Nanostructure formation and passivation of large-area black silicon for solar cell applications.

Nanoscale textured silicon and its passivation are explored by simple low-cost metal-assisted chemical etching and thermal oxidation, and large-area black silicon was fabricated both on single-crystalline Si and multicrystalline Si for solar cell applications. When the Si surface was etched by HF/AgNO(3) solution for 4 or 5 min, nanopores formed in the Si surface, 50-100 nm in diameter and 200-300 nm deep. The nanoscale textured silicon surface turns into an effective medium with a gradually varying refractive index, which leads to the low reflectivity and black appearance of the samples. Mean reflectance was reduced to as low as 2% for crystalline Si and 4% for multicrystalline Si from 300 to 1000 nm, with no antireflective (AR) coating. A black-etched multicrystalline-Si of 156 mm × 156 mm was used to fabricate a primary solar cell with no surface passivation or AR coating. Its conversion efficiency (η) was 11.5%. The cell conversion efficiency was increased greatly by using surface passivation process, which proved very useful in suppressing excess carrier recombination on the nanostructured surface. Finally, a black m-Si cell with efficiency of 15.8% was achieved by using SiO(2) and SiN(X) bilayer passivation structure, indicating that passivation plays a key role in large-scale manufacture of black silicon solar cells.