Design of Surface Plasmon Resonance-Based D-Type Double Open-Loop Channels PCF for Temperature Sensing.

Here, we document a D-type double open-loop channel floor plasmon resonance (SPR) photonic crystal fiber (PCF) for temperature sensing. The grooves are designed on the polished surfaces of the pinnacle and backside of the PCF and covered with a gold (Au) film, and stomata are distributed around the PCF core in a progressive, periodic arrangement. Two air holes between the Au membrane and the PCF core are designed to shape a leakage window, which no longer solely averts the outward diffusion of Y-polarized (Y-POL) core mode energy, but also sets off its coupling with the Au movie from the leakage window. This SPR-PCF sensor uses the temperature-sensitive property of Polydimethylsiloxane (PDMS) to reap the motive of temperature sensing. Our lookup effects point out that these SPR-PCF sensors have a temperature sensitivity of up to 3757 pm/°C when the temperature varies from 5 °C to 45 °C. In addition, the maximum refractive index sensitivity (RIS) of the SPR-PCF sensor is as excessive as 4847 nm/RIU. These proposed SPR-PCF temperature sensors have an easy nanostructure and proper sensing performance, which now not solely improve the overall sensing performance of small-diameter fiber optic temperature sensors, but also have vast application prospects in geo-logical exploration, biological monitoring, and meteorological prediction due to their remarkable RIS and exclusive nanostructure.

Ultra-Wideband High-Efficiency Solar Absorber and Thermal Emitter Based on Semiconductor InAs Microstructures.

Since the use of chemical fuels is permanently damaging the environment, the need for new energy sources is urgent for mankind. Given that solar energy is a clean and sustainable energy source, this study investigates and proposes a six-layer composite ultra-wideband high-efficiency solar absorber with an annular microstructure. It achieves this by using a combination of the properties of metamaterials and the quantum confinement effects of semiconductor materials. The substrate is W-Ti-Al2O3, and the microstructure is an annular InAs-square InAs film-Ti film combination. We used Lumerical Solutions' FDTD solution program to simulate the absorber and calculate the model's absorption, field distribution, and thermal radiation efficiency (when it is used as a thermal emitter), and further explored the physical mechanism of the model's ultra-broadband absorption. Our model has an average absorption of 95.80% in the 283-3615 nm band, 95.66% in the 280-4000 nm band, and a weighted average absorption efficiency of 95.78% under AM1.5 illumination. Meanwhile, the reflectance of the model in the 5586-20,000 nm band is all higher than 80%, with an average reflectance of 94.52%, which has a good thermal infrared suppression performance. It is 95.42% under thermal radiation at 1000 K. It has outstanding performance when employed as a thermal emitter as well. Additionally, simulation results show that the absorber has good polarization and incidence angle insensitivity. The model may be applied to photodetection, thermophotovoltaics, bio-detection, imaging, thermal ion emission, and solar water evaporation for water purification.

PbSe Quantum Dot Doped Mode-Locked Fiber Laser.

Herein, a PbSe quantum dot-doped-mode-locked fiber laser is experimentally demonstrated. A PbSe quantum dot-doped fiber is prepared using a melting method and induced as a gain medium in our mode-locked fiber laser. By increasing the pump power, a stable pulse train is obtained with a pulse duration of 36 ps, a pulse repetition rate of 4.5 MHz, an average laser power of 9.8 mW, and a central wavelength of 1214.5 nm. The pulse duration can be changed by adjusting the PC or increasing the pump power. The maximum laser power obtained was 42.7 mW under the pump power of 800 mW. Our results prove that a quantum dot-doped-mode-locked fiber laser is achievable, which provides a new scheme to solve wavelength problem of rare-earth-doped mode-locked fiber lasers.

Classification of Tea Leaves Based on Fluorescence Imaging and Convolutional Neural Networks.

The development of the smartphone and computer vision technique provides customers with a convenient approach to identify tea species, as well as qualities. However, the prediction model may not behave robustly due to changes in illumination conditions. Fluorescence imaging can induce the fluorescence signal from typical components, and thus may improve the prediction accuracy. In this paper, a tea classification method based on fluorescence imaging and convolutional neural networks (CNN) is proposed. Ultra-violet (UV) LEDs with a central wavelength of 370 nm were utilized to induce the fluorescence of tea samples so that the fluorescence images could be captured. Five kinds of tea were included and pre-processed. Two CNN-based classification models, e.g., the VGG16 and ResNet-34, were utilized for model training. Images captured under the conventional fluorescent lamp were also tested for comparison. The results show that the accuracy of the classification model based on fluorescence images is better than those based on the white-light illumination images, and the performance of the VGG16 model is better than the ResNet-34 model in our case. The classification accuracy of fluorescence images reached 97.5%, which proves that the LED-induced fluorescence imaging technique is promising to use in our daily life.

Terahertz Broadband Absorber Based on a Combined Circular Disc Structure.

To solve the problem of complex structure and narrow absorption band of most of today's terahertz absorbers, this paper proposes and utilizes the finite element (COMSOL) method to numerically simulate a broadband absorber based on a straightforward periodic structure consisting of a disk and concentric ring. The final results show that our designed absorber has an absorption rate of over 99% in the broadband range of 9.06 THz to 9.8 THz and an average of over 97.7% in the ultra-broadband range of 8.62 THz to 10 THz. The reason for the high absorption is explained by the depiction of the electric field on the absorber surface at different frequencies. In addition, the materials for the top pattern of the absorber are replaced by Cu, Ag, or Al, and the absorber still achieves perfect absorption with different metal materials. Due to the perfect symmetry of the absorber structure, the absorber is very polarization-insensitive. The overall design is simple, easy to process and production. Therefore, our research will offer great potential for applications in areas such as terahertz electromagnetic stealth, sensing, and thermal imaging.

Ultra-Wideband and Wide-Angle Perfect Solar Energy Absorber Based on Titanium and Silicon Dioxide Colloidal Nanoarray Structure.

In this paper, we designed an ultra-wideband solar energy absorber and approved it numerically by the finite-difference time-domain simulation. The designed solar energy absorber can achieve a high absorption of more than 90% of light in a continuous 3.506 µm (0.596 µm-4.102 µm) wavelength range. The basic structure of the absorber is based on silicon dioxide colloidal crystal and Ti. Since the materials have a high melting point, the designed solar energy absorber can work normally under high temperature, and the structure of this solar energy absorber is simpler than most solar energy absorbers fabricated with traditional metal. In the entire wavelength band researched, the average absorption of the colloidal crystal-based solar energy absorber is as high as 94.3%, demonstrating an excellent performance under the incidence light of AM 1.5 solar spectrum. In the meantime, the absorption spectrum of the solar energy absorber is insensitive to the polarization of light. In comparison to other similar structures, our designed solar energy absorber has various advantages, such as its high absorption in a wide spectrum range and that it is low cost and easy to make.

Hierarchical CNN-based occlusal surface morphology analysis for classifying posterior tooth type using augmented images from 3D dental surface models.

OBJECTIVE: 3D Digitization of dental model is growing in popularity for dental application. Classification of tooth type from single 3D point cloud model without assist of relative position among teeth is still a challenging task. METHODS: In this paper, 8-class posterior tooth type classification (first premolar, second premolar, first molar, second molar in maxilla and mandible respectively) was investigated by convolutional neural network (CNN)-based occlusal surface morphology analysis. 3D occlusal surface was transformed to depth image for basic CNN-based classification. Considering the logical hierarchy of tooth categories, a hierarchical classification structure was proposed to decompose 8-class classification task into two-stage cascaded classification subtasks. Image augmentations including traditional geometrical transformation and deep convolutional generative adversarial networks (DCGANs) were applied for each subnetworks and cascaded network. RESULTS: Results indicate that combing traditional and DCGAN-based augmented images to train CNN models can improve classification performance. In the paper, we achieve overall accuracy 91.35%, macro precision 91.49%, macro-recall 91.29%, and macro-F1 0.9139 for the 8-class posterior tooth type classification, which outperform other deep learning models. Meanwhile, Grad-cam results demonstrate that CNN model trained by our augmented images will focus on smaller important region for better generality. And anatomic landmarks of cusp, fossa, and groove work as important regions for cascaded classification model. CONCLUSION: The reported work has proved that using basic CNN to construct two-stage hierarchical structure can achieve the best classification performance of posterior tooth type in 3D model without assistance of relative position information. The proposed method has advantages of easy training, great ability to learn discriminative features from small image region.

Aberration-free digital holographic phase imaging using the derivative-based principal component analysis.

SIGNIFICANCE: Digital holographic microscopy is widely used to get the quantitative phase information of transparent cells. AIM: However, the sample phase is superimposed with aberrations. To quantify the phase information, aberrations need to be fully compensated. APPROACH: We propose a technique to obtain aberration-free phase imaging, using the derivative-based principal component analysis (dPCA). RESULTS: With dPCA, almost all aberrations can be extracted and compensated without requirements on background segmentation, making it efficient and convenient. CONCLUSIONS: It solves the problem that the conventional principal component analysis (PCA) algorithm cannot compensate the common but intricate higher order cross-term aberrations, such as astigmatism and coma. Moreover, the dPCA strategy proposed here is not only suitable for aberration compensation but also applicable for other cases where there exist cross-terms that cannot be analyzed with the PCA algorithm.

3D distribution of dental plaque on occlusal surface using 2D-fluorescence-image to 3D-surface registration.

The accumulation of dental plaque on a tooth surface plays a crucial role in developing dental caries. In this paper, fluorescence imaging modality with structured light-based intraoral 3D scanner were combined to investigate the 3D distribution of dental plaque. The traditional fluorescence imaging method only reveals the 2D spatial distribution of the dental plaque on a tooth surface. To visualize the 3D distribution of the dental plaque on an occlusal surface, mapping a 2D fluorescence image to a 3D occlusal surface was investigated. An iterative closest point (ICP)-based contour registration method was proposed. A fluorescence camera was calibrated to obtain intrinsic parameters. The rotation and translation matrices for projecting the 3D occlusal surface were optimized to match the contours of the 2D fluorescence image and the 3D projected model. The 3D distribution of occlusal plaque reveals that dental plaque accumulation relates to the local and global morphology of the tooth surface. Thus, the depth of the pit-and-fissure is not the only parameter used to determine plaque content. The investigation of the 3D distribution of occlusal plaque using 2D-3D registration paves the path for the quantitative analysis of the tooth surface morphology to perform plaque-guided caries risk assessment.

Robust Classification of Tea Based on Multi-Channel LED-Induced Fluorescence and a Convolutional Neural Network.

A multi-channel light emitting diode (LED)-induced fluorescence system combined with a convolutional neural network (CNN) analytical method was proposed to classify the varieties of tea leaves. The fluorescence system was developed employing seven LEDs with spectra ranging from ultra-violet (UV) to blue as excitation light sources. The LEDs were lit up sequentially to induce a respective fluorescence spectrum, and their ability to excite fluorescence from components in tea leaves were investigated. All the spectral data were merged together to form a two-dimensional matrix and processed by a CNN model, which is famous for its strong ability in pattern recognition. Principal component analysis combined with k-nearest-neighbor classification was also employed as a baseline for comparison. Six grades of green tea, two types of black tea and one kind of white tea were verified. The result proved a significant improvement in accuracy and showed that the proposed system and methodology provides a fast, compact and robust approach for tea classification.

[Dynamics of Proliferation and Differentiation after Transplantation of Hematopoietic Cells in Mouse].

OBJECTIVE: To investigate the effects of Listeria monocytogenes infection on hematopoietic stem and progenitor cell (HSPC) composition, cell cycle and cell colony-forming ability in mouse bone marrow. METHODS: The C57BL/6J mice were divided into infected group and control group. The mice in injected group were infected intraperitoneally with 6.7×106 CFU Listeria monocytogenes,while the mice in control group were injecfed with PBS of same volume.The serum levels of IFNγ were detected at different time points. After 24 hours, the HS/PC composition, cell cycle and cell colony-forming ability in bone marrow of mice were measured, and the difference between the control group and the infected group was statistically analyzed. RESULTS: Serum IFNγ levels peaked at 24 hours after infection with Listeria monocytogenes. After 24 h, the proportion of LSK, LSK in S phase, and short-term hematopoietic stem cells (ST-HSC) in the infected group were significantly higher than those in the control group (P＜0.001), long-term hematopoietic stem cells (LT-HSC) and the proportion of LT-HSC in S phase were significantly increased (P＜0.01), and the cell colony-forming ability of bone marrow significantly decreased (P＜0.01). [WTHZ]Conclusion: [WTB1]After infection with Listeria monocytogenes, bone marrow hematopoietic stem cells enter the proliferative state from rest, the cell colony-forming ability decreases, suggesting that Listeria monocytogenes infection can cause hematopoietic stem cell depletion.

Digital holographic phase imaging with aberrations totally compensated.

Digital holography is a well-accepted method for phase imaging. However, the phase of the object is always embedded in aberrations. Here, we present a digital holographic phase imaging with the aberrations fully compensated, including the high order aberrations. Instead of using pre-defined aberration models or 2D fitting, we used the simpler and more flexible 1D fitting. Although it is 1D fitting, data across the whole plane could be used. Theoretically, all types of aberrations can be compensated with this method. Experimental results show that the aberrations have been fully compensated and the pure object phase can be obtained for further studies.

Computer-aided detection of small intestinal ulcer and erosion in wireless capsule endoscopy images.

A novel computer-aided detection method based on deep learning framework was proposed to detect small intestinal ulcer and erosion in wireless capsule endoscopy (WCE) images. To the best of our knowledge, this is the first time that deep learning framework has been exploited on automated ulcer and erosion detection in WCE images. Compared with the traditional detection method, deep learning framework can produce image features directly from the data and increase recognition accuracy as well as efficiency, especially for big data. The developed method included image cropping and image compression. The AlexNet convolutional neural network was trained to the database with tens of thousands of WCE images to differentiate lesion and normal tissue. The results of ulcer and erosion detection reached a high accuracy of 95.16% and 95.34%, sensitivity of 96.80% and 93.67%, and specificity of 94.79% and 95.98%, correspondingly. The area under the receiver operating characteristic curve was over 0.98 in both of the networks. The promising results indicate that the proposed method has the potential to work in tandem with doctors to efficiently detect intestinal ulcer and erosion.

Decrease of galectin-3 in keratinocytes: A potential diagnostic marker and a critical contributor to the pathogenesis of psoriasis.

Psoriasis-specific proteins dysregulated in keratinocytes and involved in the pathophysiological process of psoriasis remains elusive. We report here that epidermal galectin-3 expression is significantly downregulated in lesional skin, but not in non-lesional skin in psoriasis patients, nor in a group of diseases known as psoriasiform dermatitis clinically and histologically similar to psoriasis. The deficiency of epidermal galectin-3 is sufficient to promote development of psoriatic lesions, as evidenced by more severe skin inflammation in galectin-3 knockout (gal3-/-) mice, compared to wild-type mice, after imiquimod treatment, and in skin from gal3-/- mice grafted onto wildtype mice. The development of psoriatic-like lesions is attributable to 1) the spontaneously tuning up of psoriasis signatures in keratinocytes through JNK pathway; and 2) neutrophil accumulation caused by the enhanced leukocyte-recruiting capacity associated with overexpression of S100A7-9 and CXCL-1, 8 in keratinocytes with impaired galectin-3 expression. Psoriasis-like skin inflammation is significantly improved in gal-3-/- mice both by inhibition of neutrophils accumulation with a selective CXCR2 antagonist of SB225002, and by intracutaneous injection of recombinant galectin-3. Overall, these findings offer promising galectin-3-related diagnostic and therapeutic resolutions of psoriasis.

Passively mode-locked Yb fiber laser with PbSe colloidal quantum dots as saturable absorber.

A passively mode-locked Yb fiber laser using PbSe colloidal quantum dots (CQDs) as saturable absorber (SA) is experimentally demonstrated. An all-fiber experimental scheme was designed to understand the SA property of PbSe CQDs. The non-saturable loss, modulation depth, and saturable intensity of SA measured were 23%, 7%, and 12 MW/cm2, respectively. The PbSe CQDs were sandwiched in a fiber connector, which was further inserted into the Yb fiber laser for mode-locking. As the pump power up to 110 mW, the self-starting mode-locking pulses were observed. Under the pump power of 285 mW, a maximum average laser power with fundamental mode-locking operation was obtained to be 21.3 mW. In this situation, the pulse full width at half maximum (FWHM), pulse repetition rate, and spectral FWHM were measured to be 70 ps, 8.3 MHz, and 4.5 nm, respectively.

Near-field thermal radiation of deep- subwavelength slits in the near infrared range.

We numerically investigate the thermal radiation of one-dimensional deep subwavelength slits in the near infrared range. Using numerical calculations of single-slit and multi-slit structures, we find that high-level radiation efficiency can be achieved for a wide spectrum when ultra-thin intermediate layers are used, and it is less affected by structure parameters. The underlying mechanisms involve Surface Plasmon Polaritons resonance and Fabry-Perot interference at each slit and the interaction between adjacent slits. This structure helps understand and improve the design of thermal radiation control devices.

Association of anti-acidic ribosomal protein P0 and anti-galectin 3 antibodies with the development of skin lesions in systemic lupus erythematosus.

OBJECTIVE: The specific autoantibodies and antigens that mediate systemic lupus erythematosus (SLE)-related organ injuries remain largely unknown. This study was undertaken to investigate the antibody-mediated immune response that leads to SLE skin lesions. METHODS: The study included 85 SLE patients with lupus-specific skin lesions and 31 without skin lesions. The reactivity of serum antibody with skin antigens was determined by immunoblotting using human foreskin as the substrate. Skin antigens were identified using mass spectrometry. Serum antibody was isolated by affinity purification and was injected intracutaneously into mouse skin to determine pathogenicity. Serum antibody levels were monitored by enzyme-linked immunosorbent assay. RESULTS: We determined that 78% of the patients with skin lesions had serum antibodies reactive with 35-kd and/or 25-kd skin antigens, which was significantly higher than the percentage of patients without skin lesions (P < 0.0001), suggesting a correlation between immune response and skin lesions. Acidic ribosomal protein P0 (RPLP0) and galectin 3 were 2 target antigens identified from 35-kd and 25-kd proteins, respectively. Purified serum anti-RPLP0 and anti-galectin 3 antibodies induced lupus-like histologic changes after intracutaneous injection. Anti-RPLP0 and anti-galectin 3 antibody levels were significantly higher in SLE patients than in healthy controls and decreased with skin recovery. Anti-galectin 3 antibody levels were not significantly higher in SLE patients than in patients with dermatomyositis or scleroderma, but strongly related to lupus cutaneous vasculitis. Additionally, levels of the 2 antibodies were positively correlated with leukopenia and C3 deficiency, and the anti-RPLP0 antibody level was also positively correlated with arthritis and SLE disease activity. CONCLUSION: Our findings indicate that the immune response mediated by serum anti-RPLP0 and anti-galectin 3 antibodies plays a key role in the pathogenesis of SLE skin lesions. These findings provide new insights into the mechanism of SLE-related organ disorders.

Fiber laser pumped high power mid-infrared laser with picosecond pulse bunch output.

We report a novel quasi-synchronously pumped PPMgLN-based high power mid-infrared (MIR) laser with picosecond pulse bunch output. The pump laser is a linearly polarized MOPA structured all fiberized Yb fiber laser with picosecond pulse bunch output. The output from a mode-locked seed fiber laser was directed to pass through a FBG reflector via a circulator to narrow the pulse duration from 800 ps to less than 50 ps and the spectral FWHM from 9 nm to 0.15 nm. The narrowed pulses were further directed to pass through a novel pulse multiplier through which each pulse was made to become a pulse bunch composing of 13 sub-pulses with pulse to pulse time interval of 1.26 ns. The pulses were then amplified via two stage Yb fiber amplifiers to obtain a linearly polarized high average power output up to 85 W, which were then directed to pass through an isolator and to pump a PPMgLN-based optical parametric oscillator via quasi-synchronization pump scheme for ps pulse bunch MIR output. High MIR output with average power up to 4 W was obtained at 3.45 micron showing the feasibility of such pump scheme for ps pulse bunch MIR output.

High-power multichannel PPMgLN-based optical parametric oscillator pumped by a master oscillation power amplification-structured Q-switched fiber laser.

We experimentally demonstrated a compact fiber laser-pumped multichannel PPMgLN-based optical parametric oscillator (OPO) generating total OPO output power of 15.8, 15.2, 14.2, 12.9, and 8.8 W with idler output power of 4.7, 4.3, 4.1, 3.3, and 2.1 W at the wavelength of 3.43, 3.63, 3.72, 3.83, and 3.99 µm, respectively. The OPO was pumped by a fully fiberized polarization maintaining (PM) ytterbium-doped pulsed fiber master oscillation power amplifier (MOPA) operating at 1064 nm at a repetition rate of 65 kHz with effective pump power of 28.7 W. The MOPA system was constructed with an acousto-optic Q-switched fiber laser seed and only one stage PM fiber amplifier without any free space components, which makes the pump system compact and stable in the long-term. Comparisons on efficiencies and signal wavelength shifts between different channels showed that the idler absorption was the main factor preventing high average-power OPO operation with long idler wavelength.

Establishment of two-dimensional gel electrophoresis profiles of the human acute promyelocytic leukemia cell line NB4.

To explore optimum conditions for establishing a two­dimensional gel electrophoresis (2-DE) map of the human acute promyelocytic leukemia (APL) cell line NB4 and to analyze its protein profiles, we extracted total proteins from NB4 cells using cell disruption, liquid nitrogen freeze-thawing and fracturing by ultrasound, and quantified the extracted protein samples using Bradford's method. 2-DE was applied to separate the proteins, which were silver-stained in the gel. Well­separated protein spots were selected from the gel using the ImageMaster™ 2D Platinum analysis system. Moreover, the effects of various protein sample sizes (140, 160 and 180 µg) on the 2-DE maps of the NB4 cells were determined and compared. Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS), peptide mass fingerprinting (PMF) and database searching were used to identify the proteins. When the quantity of loading proteins was 160 µg, clear, well-resolved, reproducible 2-DE proteomic profiles of the NB4 cells were obtained. The average number of protein spots in 3 gels was 1160±51 with an average matching rate of 81%. A total of 10 proteins were identified by mass spectrometry and database queries, certain proteins were products of oncogenes and others were involved in cell cycle regulation and signal transduction. In summary, 2-DE profiles of the proteome of NB4 cells were established and certain proteins were identified by MALDI-TOF-MS and PMF which lay the foundation of further proteomic research of NB4 cells. These data should be useful for establishing a human APL proteome database.