Towards a more practical analysis of Newton's rings using deep learning.

As a typical form of optical fringes with a quadratic phase, Newton's ring patterns play an important role in spherical measurements and optical interferometry. A variety of methods have been used to analyze Newton's ring patterns. However, it is still rather challenging to fulfill the analysis. We present a deep-learning-based method to estimate the parameters of Newton's ring patterns and fulfill the analysis accordingly. The experimental results indicate the excellent accuracy, noise robustness, and demodulation efficiency of our method. It provides another applicable approach to analyzing Newton's ring patterns and brings insights into fringe analysis and interferometry-based measurements.

Concise fractional Fourier transform based on a non-uniform order searching method for estimating physical parameters from Newton's rings.

Newton's ring pattern is very common in interferometry. By analyzing it, the physical parameters can be estimated, such as the curvature radius and the rings' center. However, parameter estimation from large images using fractional Fourier transform (FRFT) consumes considerable time. A concise FRFT based on a non-uniform order searching method is proposed to reduce the computational time without decreasing the accuracy. Experimental results show that the time of the proposed method is about 2.7 s, which is about 1/600 of that of the traditional FRFT-based method and 1/5 of that of the Fast FRFT-based method when processing 960×960 pixel images.

Convolutional neural network for estimating physical parameters from Newton's rings.

By analyzing Newton's rings, often encountered in interferometry, the parameters of spherical surfaces such as the rings' center and the curvature radius can be estimated. First, the classical convolutional neural networks, visual geometry group (VGG) network and U-Net, are applied to parameter estimation of Newton's rings. After these models are trained, the rings' center and curvature radius can be obtained simultaneously. Compared with previous analysis methods of Newton's rings, it is shown that the proposed method has higher precision, better immunity to noise, and lower time consumption. For a Newton's rings pattern of ${{640}} \times {{480}}$ pixels comprising ${-}{{5}}\;{\rm{dB}}$ Gaussian noise or 60% salt-and-pepper noise, the parameters can be estimated by the VGG model in 0.01 s, the error of the rings' center is less than one pixel, and the error of curvature radius is lower than 0.5%.

Impact of background and modulation on parameter estimation using fractional Fourier transform and its solutions.

Analysis of closed-fringe patterns with quadratic phase that are often encountered plays an important role in optical interferometry. But because the frequency spectra of the two exponential signals that compose closed-fringe patterns overlap in the Fourier domain while one is clearly distinct from the other in the fractional Fourier domain, fractional Fourier transform (FRFT) is a useful method for analyzing the images to provide parameter estimation. However, when the fringe pattern has varying background and/or modulation due to non-uniform illumination, parameter estimation accuracy based on FRFT is affected, which lacks theoretical justification. Thus, the impact of varying background and/or modulation on the FRFT is studied with theoretic analysis and presented in this paper. Key factors that contribute to the optimal results are discussed when employing three kinds of fringe normalization methods to eliminate the impact. Here, the fringe pattern is first processed by the normalization technique. Then the cosine-only term is used to estimate parameter by use of the FRFT-based method. Physical quantities are then obtained by parameter estimation. In comparison with our previous method based on FRFT, more accurate results are achieved. The feasibility and applicability of the proposed approach are demonstrated using simulation and experimental results.

Fast FRFT-based method for estimating physical parameters from Newton's rings.

By analyzing Newton's rings, often encountered in interferometry, using fractional Fourier transform (FRFT), we can estimate the physical parameters, such as the curvature radius of the spherical surface and the rings' center. However, parameter estimation from large images using FRFT consumes considerable time. We introduce an improved method that resamples the image before applying FRFT. Because Newton's rings are sparse in the FRFT domain, this method reduces the computational time without decreasing the accuracy. Experimental results show that compared to traditional FRFT-based algorithms, this method can estimate parameters in about 1.3 s when processing 1920×1080 pixel images.

Silicon-based dual ARROW power splitters with remote coupling.

In this research, Si-based power splitters based on dual antiresonant reflecting optical waveguides (ARROW) with remote coupling by a separation distance of 30 µm were designed and realized. Characterization of the power splitters with different lengths of the coupling region was performed. Measurement characteristics of fabricated devices with the propagation losses lower than 1.90 dB/cm and the imbalances lower than 0.60 dB show that our dual ARROW power splitters can be efficiently realized.

In Situ Regeneration of Si-based ARROW-B Surface Plasmon Resonance Biosensors.

Si-based antiresonant reflecting optical waveguide type B (ARROW-B) surface plasmon resonance (SPR) biosensors allow label-free high-sensitivity detection of biomolecular interactions in real time. The ARROW-B waveguide, which has a thick guiding layer, provides efficient coupling with a single-mode fiber. The Si-based ARROW-B SPR biosensors were fabricated by using the standard semiconductor fabrication processes with a single-step lithography. A fluid flow system was designed to transport samples or analytes. The waveguide consists of propagation and SPR sensing regions. The propagation regions in the front and rear of the SPR sensing region have a symmetric cladding structure to isolate them from environmental changes. A high-index O-ring is used to seal the liquid flow channel. The intensity interrogation method was used to characterize the sensors. The sensitivity of the biosensors was 3.0 × 103 µW/RIU (refractive index unit) with a resolution of 6.2 × 10-5 RIU. An in situ regeneration process was designed to make the sensors reusable and eliminate re-alignment of the optical measurement system. The regeneration was realized using ammonia-hydrogen peroxide mixture solutions to remove molecules bound on the sensor surface, such as self-assembled 11-mercapto-1undecanoic acid and bovine serum albumin. SPR was used to monitor the regeneration processes. The experimental results show that the sensing response did not significantly change after the sensor was reused more than 10 times. In situ regenerations of the sensors were achieved.

Where do health benefits of flavonoids come from? Insights from flavonoid targets and their evolutionary history.

Flavonoid intake is negatively correlated with the incidence of some chronic diseases including cardiovascular diseases, type II diabetes, neurodegenerative diseases, and cancers. Thus, the molecular mechanisms underlying this correlation are of great interest. Although ample attention has been given to the free radical-scavenging potential of flavonoids, the poor bioavailability of exogenous flavonoids suggests that the direct antioxidant activity is unlikely responsible for their favorable effects. This study comprehensively analyzed flavonoid targets. The results show that the main functions of these targets are associated with cancers and cardiovascular and metabolic diseases. Moreover, evolutionary analysis of these targets showed that ~1000 of the targets have homologues in human gut bacterial metagenomes. Clusters of orthologous groups of proteins (COG) analysis indicated that most of these bacterial targets are associated with bacterial metabolism. Given that the metabolism of gut microbiota is coupled with the metabolism of the host, this finding implies that flavonoids exert their benefits by regulating gut microbes. Therefore, the health benefits of flavonoids are well explained by their targets rather than their direct antioxidant potential.

Reconstructing a flavodoxin oxidoreductase with early amino acids.

Primitive proteins are proposed to have utilized organic cofactors more frequently than transition metals in redox reactions. Thus, an experimental validation on whether a protein constituted solely by early amino acids and an organic cofactor can perform electron transfer activity is an urgent challenge. In this paper, by substituting "late amino acids (C, F, M, T, W, and Y)" with "early amino acids (A, L, and V)" in a flavodoxin, we constructed a flavodoxin mutant and evaluated its characteristic properties. The major results showed that: (1) The flavodoxin mutant has structural characteristics similar to wild-type protein; (2) Although the semiquinone and hydroquinone flavodoxin mutants possess lower stability than the corresponding form of wild-type flavodoxin, the redox potential of double electron reduction Em,7 (fld) reached -360 mV, indicating that the flavodoxin mutant constituted solely by early amino acids can exert effective electron transfer activity.

[Value of arterial lactic acid and buffer excess in predicting the prognosis of patients with paraquat poisoning].

OBJECTIVE: To investigate the early prognostic values of arterial lactate and base excess (BE) in patients with paraquat poisoning. METHODS: Seventy-five patients with paraquat poisoning were divided into sudden death group (n = 10) who died within 24 h after admission, recent death group (n = 31) who died more than 24 h after admission, and survival group (n = 34). Arterial lactate and BE were measured on admission and at 24 h after admission. The prognostic values of arterial lactate and BE were analyzed. RESULTS: The arterial lactate measured on admission was significantly higher in the sudden death group than in the recent death group and survival group (P < 0.01), but there was no significant difference in arterial lactate between the recent death group and survival group (P = 0.309). The BE measured on admission was significantly lower in the sudden death group than in the recent death group and survival group, and it was significantly lower in the recent death group than in the survival group (P < 0.01 or P < 0.05). At 24 h after admission, the recent death group had a significantly higher arterial lactate (P < 0.01) and a significantly lower BE (P < 0.01), as compared with the survival group. The logistic regression analysis showed that the two indices were significantly associated with prognosis (P < 0.01). On admission, the areas under the receiver operating characteristic (ROC) curve (AUCs) of arterial lactate and BE for predicting death were 0.692 and 0.787, respectively, and the cut-off values were 3.25 mmol/L and -1.75 mmol/L, respectively; the AUCs of arterial lactate and BE for predicting sudden death were 0.995 and 1, respectively, and the cut-off values were 7.1 mmol/L and -12.8 mmol/L, respectively. At 24 h after admission, the AUCs of arterial lactate and BE for predicting death were 0.743 and 0.822, respectively, and the cut-off values were 2.15 mmol/L and -5.55 mmol/L, respectively. CONCLUSION: Arterial lactate and BE have certain values in predicting the death, especially the sudden death, in patients with acute paraquat poisoning.

Design, fabrication, and characterization of Si-based ARROW photonic crystal bend waveguides and power splitters.

Silicon-based (Si-based) photonic crystal waveguide based on antiresonant reflecting optical waveguide (ARROW PCW) structures consisting of 60° bends and Y-branch power splitters were designed and first efficiently fabricated and characterized. The ARROW structure has a relatively large core size suitable for efficient coupling with a single-mode fiber. Simple capsule-shaped topography defects at 60° photonic crystal (PC) bend corners and Y-branch PC power splitters were used for increasing the broadband light transmission. In the preliminary measurements, the propagation losses of the ARROW PC straight waveguides lower than 2 dB/mm with a long length of 1500 µm were achieved. The average bend loss of 60° PC bend waveguides was lower than 3 dB/bend. For the Y-branch PC power splitters, the average power imbalance was lower than 0.6 dB. The results show that our fabricated Si-based ARROW PCWs with 60° bends and Y-branch structures can provide good light transmission and power-splitting ability.

Zero-order noise suppression with various space-shifting manipulations of reconstructed images in digital holography.

In this paper, we describe various numerical space-shifting manipulations of the reconstructed images to remove the dc noise in the reconstruction, in terms of the periodicity characteristics of images in digital holography. The theoretical interpretation on different reconstruction periods of the image and the dc noise is described in detail for the first time, to the best of our knowledge. It is related to CCD sampling periods or frequencies for the fringes and the dc term of a hologram. With the calculations of Hadamard product of two different spatially shifted images and subsequent extraction of the root of it, the dc noise can be suppressed effectively and a clear image with the original intensity contrast can be obtained at the center in the hologram reconstruction, particularly when the image and the dc noise are completely or partially superposed with each other. The experiments for both in-line and off-axis imaging cases show that all results are completely consistent with theoretical predictions.

[Arthroscopic Bankart repair combined with Reimplissage for the treatment of recurrent anterior dislocation of shoulder in adults with Hill-Sachs defect].

OBJECTIVE: To investigate the method and clinical effects of the treatment of recurrent anterior dislocation of shoulder with Hill-Sachs injury by arthroscopic Bankart repair and Remplissage. METHODS: From March 2016 to March 2019, 106 patients with recurrent anterior dislocation of shoulder with glenoid bone defect less than 20% underwent arthroscopic Bankart repair, including 76 males and 30 females, aged from 18 to 45 (27.3±8.6) years, 59 cases of left shoulder and 47 cases of right shoulder. Range of motion (ROM), American Shoulder and Elbow Surgeons(ASES) score, Constant-Murley score and Rowe score were used to evaluate shoulder functionand stability before and after operation. RESULTS: All patients were followed up, and the duration ranged from 21 to 60 months, with a mean of (41.5± 8.5) months. One patient developed infection after operation, and the infection was controlled after arthroscopic debridement again. The remaining patients did not have clinical complications such as infection, intra articular hematocele and redislocation. Shoulder flexion and lifting increased from (158.33±15.72) ° preoperatively to (169.43±10.04) ° at the latest follow up, and internal rotation changed from T7 (T4 to T10) preoperatively to T8 (T5 to T10) at the latest follow up;the average lateral external rotation and abduction 90 ° external rotation decreased from (58.46±15.51) ° preoperatively and (99.37±14.09) ° to (53.18±14.90) ° and (92.52±13.10) ° at the latest follow up, respectively. The ASES score, Constant -Murley score and Rowe score were significantly improved. CONCLUSION: The clinical effect of rehabilitation of Bankart repair combined with Remplissageunder arthroscopy in the treatment of recurrent dislocation of shoulder joint in adults with Hill-Sachs defect is satisfactory. Although the external rotation function is weaker than that before operation, it can effectively reconstruct the shoulder function and avoid the occurrence ofdislocation after operation.

Ultracompact photonic crystal polarization beam splitter based on multimode interference.

We propose a theoretical design for a compact photonic crystal (PC) polarization beam splitter (PBS) based on the multimode interference (MMI) effect. The size of a conventional MMI device designed by the self-imaging principle is not compact enough; therefore, we design a compact PC PBS based on the difference of the interference effect between TE and TM modes. Within the MMI coupler, the dependence of interference of modes on propagation distance is weak for a TE wave and strong for a TM wave; as a result, the length of the MMI section can be only seven lattice constants. Simulation results show that the insertion losses are 0.32 and 0.89 dB, and the extinction ratios are 14.4 and 17.5 dB for Port 1 (TE mode) and Port 2 (TM mode), respectively.

Effects of Cofactors on Conformation Transition of Random Peptides Consisting of a Reduced Amino Acid Alphabet.

This study aims to explore the structure characteristic of random polypeptides constructed by origin early amino acid alphabet, as well as the effects of cofactors on conformation transition of random peptides. DNA library R8-4 encoding VNM random peptides were constructed by small cassette strategy. Subsequently, a random polypeptide library was constructed using in vitro translation. Expression and purification of VNM random peptides were also performed by a conventional method of recombinant. CD spectrum analysis indicated that VNM random polypeptides have a secondary structure characteristic of protein, such as the content of α-helix is greater than 60%, random coil is about 20% ß sheet, and ß turn is less than 10%. CD spectrum changed with the addition of 10-40 µM ATP and NADP, but slightly changed by NAD; no influence was observed with MgSO4. Bis-ANS binding assay indicated that fluorescent intensity of bis-ANS was strengthened slightly by 10 VNM random peptides. Fluorescent intensity was strengthened fourfold by adding 10-40 µM ATP, NAD, and NADH, whereas the inducing effect of NADPH and MgSO4 were negligible. VNM random peptides have a classic secondary structure and hydrophobic domain in water solution. Moreover, conformation transition and hydrophobic domain could be induced by cofactor, indicating the preliminary evidence for the hypothesis that "the origin of primitive protein was induced by small molecule."

Double-layer networks with holographic optical switches.

The double-layer networks have the advantages of being strictly nonblocking and having a simpler routing algorithm, the lowest system insertion loss, a zero differential loss, fewer drivers, fewer interconnection lines, fewer crossovers, and the best signal-to-noise-ratio characteristic compared with any nondilated network. Using holographic optical switches to construct these networks not only eliminates all interconnection lines and crossovers but also reduces the number of drivers.