Fast digital refocusing Fourier ptychographic microscopy method based on convolutional neural network.

Fourier ptychographic microscopy (FPM) is used to achieve high resolution and a large field of view. However, traditional FPM image reconstruction methods often yield poor image quality when encountering out-of-focus issues during reconstruction. Therefore, this study proposes a defocus-distance regression network based on convolutional neural networks. In an experimental validation, the root-mean-square error calculated from 1000 sets of predicted and true values was approximately 6.2 µm. The experimental results suggest that the proposed method has good generalization, maintains high accuracy in predicting defocus distances even for different biological samples, and extends the imaging depth-of-field of the FPM system by a factor of more than 3.

Fast Fourier ptychographic quantitative phase microscopy for in vitro label-free imaging.

Quantitative phase microscopy (QPM) is indispensable in biomedical research due to its advantages in unlabeled transparent sample thickness quantification and obtaining refractive index information. Fourier ptychographic microscopy (FPM) is among the most promising QPM methods, incorporating multi-angle illumination and iterative phase recovery for high-resolution quantitative phase imaging (QPI) of large cell populations over a wide field of-view (FOV) in a single pass. However, FPM is limited by data redundancy and sequential acquisition strategies, resulting in low imaging efficiency, which in turn limits its real-time application in in vitro label-free imaging. Here, we report a fast QPM based on Fourier ptychography (FQP-FPM), which uses an optimized annular downsampling and parallel acquisition strategy to minimize the amount of data required in the front end and reduce the iteration time of the back-end algorithm (3.3% and 4.4% of conventional FPM, respectively). Theoretical and data redundancy analyses show that FQP-FPM can realize high-throughput quantitative phase reconstruction at thrice the resolution of the coherent diffraction limit by acquiring only ten raw images, providing a precondition for in vitro label-free real-time imaging. The FQP-FPM application was validated for various in vitro label-free live-cell imaging. Cell morphology and subcellular phenomena in different periods were observed with a synthetic aperture of 0.75 NA at a 10× FOV, demonstrating its advantages and application potential for fast high-throughput QPI.

Fast and robust Fourier ptychographic microscopy with position misalignment correction.

Significance: Fourier ptychographic microscopy (FPM) is a new, developing computational imaging technology. It can realize the quantitative phase imaging of a wide field of view and high-resolution (HR) simultaneously by means of multi-angle illumination via a light emitting diode (LED) array, combined with a phase recovery algorithm and the synthetic aperture principle. However, in the FPM reconstruction process, LED position misalignment affects the quality of the reconstructed image, and the reconstruction efficiency of the existing LED position correction algorithms needs to be improved. Aim: This study aims to improve the FPM correction method based on simulated annealing (SA) and proposes a position misalignment correction method (AA-C algorithm) using an improved phase recovery strategy. Approach: The spectrum function update strategy was optimized by adding an adaptive control factor, and the reconstruction efficiency of the algorithm was improved. Results: The experimental results show that the proposed method is effective and robust for position misalignment correction of LED arrays in FPM, and the convergence speed can be improved by 21.2% and 54.9% compared with SC-FPM and PC-FPM, respectively. Conclusions: These results can reduce the requirement of the FPM system for LED array accuracy and improve robustness.

Aromatics production from relay catalytic pyrolysis of cow manure using Ru/C and ZSM-5 dual catalysts synthesized from coal gasification fine slag.

Resource utilization of solid waste can aid in gradual substitution of fossil fuels while achieving waste recycling. In this study, residual carbon and ash slag from the coal gasification fine slag were separated by froth flotation, and then was used to prepare Ru/C and ZSM-5 dual catalysts with carbon-rich and ash-rich components as raw materials, respectively. The performance of two catalysts for catalytic upgrading of volatiles from pyrolysis of cow manure (CM) to produce light aromatic hydrocarbons was systematically investigated. The direct pyrolysis products of CM mainly included alcohols, ketones, ethers, and other oxygen-containing compounds. When ZSM-5 was used as the catalyst, the yield of monocyclic aromatic hydrocarbons (MAHs) increased significantly due to the better catalytic cracking and aromatization abilities of ZSM-5 catalyst. However, the yield of phenols in the pyrolysis products improved when Ru/C was used as the catalyst due to the cleavage effect of Ru/C on the C-O bond. When Ru/C and ZSM-5 were used as dual catalysts in relay catalytic pyrolysis of volatiles, the increase in MAHs yield in the pyrolysis product was higher than the total increase obtained under Ru/C and ZSM-5 single catalysis. The possible pathways for the generation of MAHs from CM under Ru/C and ZSM-5 relay catalytic pyrolysis were revealed by the pyrolysis experiment performed on model compounds.

Adaptive correction method of hybrid aberrations in Fourier ptychographic microscopy.

Significance: Fourier ptychographic microscopy (FPM) enables quantitative phase imaging with a large field-of-view and high resolution by acquiring a series of low-resolution intensity images corresponding to different spatial frequencies stitched together in the Fourier domain. However, the presence of various aberrations in an imaging system can significantly degrade the quality of reconstruction results. The imaging performance and efficiency of the existing embedded optical pupil function recovery (EPRY-FPM) aberration correction algorithm are low due to the optimization strategy. Aim: An aberration correction method (AA-P algorithm) based on an improved phase recovery strategy is proposed to improve the reconstruction image quality. Approach: This algorithm uses adaptive modulation factors, which are added while updating iterations to optimize the spectral function and optical pupil function updates of the samples, respectively. The effectiveness of the proposed algorithm is verified through simulations and experiments using an open-source biological sample dataset. Results: Experimental results show that the proposed AA-P algorithm in an optical system with hybrid aberrations, recovered complex amplitude images with clearer contours and higher phase contrast. The image reconstruction quality was improved by 82.6% when compared with the EPRY-FPM algorithm. Conclusions: The proposed AA-P algorithm can reconstruct better results with faster convergence, and the recovered optical pupil function can better characterize the aberration of the imaging system. Thus, our method is expected to reduce the strict requirements of wavefront aberration for the current FPM.

Reduction in required volume of imaging data and image reconstruction time for adaptive-illumination Fourier ptychographic microscopy.

Fourier ptychographic microscopy (FPM) is a promising super-resolution computational imaging technology. It stitches a series of low-resolution (LR) images in the Fourier domain by an iterative method. Thus, it obtains a large field of view and high-resolution quantitative phase images. Owing to its capability to perform high-spatial bandwidth product imaging, FPM is widely used in the reconstruction of conventional static samples. However, the influence of the FPM imaging mechanism limits its application in high-speed dynamic imaging. To solve this problem, an adaptive-illumination FPM scheme using regional energy estimation is proposed. Starting with several captured real LR images, the energy distribution of all LR images is estimated, and select the measurement images with large information to perform FPM reconstruction. Simulation and experimental results show that the method produces efficient imaging performance and reduces the required volume of data to more than 65% while ensuring the quality of FPM reconstruction.

Fast and stable Fourier ptychographic microscopy based on improved phase recovery strategy.

Fourier ptychographic microscopy (FPM) imaging is a computational imaging technology that can reconstruct wide-field high-resolution (HR) images. It uses a series of low-resolution images captured by a camera under different illumination angles. The images are stitched in the Fourier domain to expand their spectral range. Under high-angle illumination, a dark-field image is noisy with a low signal-to-noise ratio, which significantly reduces the reconstruction quality of FPM. Conventional reconstruction algorithms often have low FPM imaging performance and efficiency due to optimization strategies. In response to these problems, this paper proposes an FPM imaging method based on an improved phase recovery strategy to optimize the alternating iterative algorithm. The technique uses an improved threshold method to reduce noise in the image preprocessing stage to maximize the retention of high-frequency sample information. Moreover, an adaptive control factor is added in the subsequent iterative update process to balance the sample spectrum function. This study verifies the effectiveness of the proposed method on both simulation and experimental images. The results show that the proposed method can effectively suppress image background noise and has a faster convergence speed and higher robustness. In addition, it can be used to reconstruct HR complex amplitude images of objects under wide field-of-view conditions.

A Facile Probe for Fluorescence Turn-on and Simultaneous Naked-Eyes Discrimination of H2S and biothiols (Cys and GSH) and Its Application.

Hydrogen sulfide and biothiol molecules such as Cys and GSH acted important roles in many physiological processes. To simultaneously detect and distinguish them was quite necessary by a suitable fluorescent probe. A novel chemosensor 4-(4-(benzo[d]thiazol-2-yl)-2-methoxyphenoxy)-7-nitrobenzo[c][1,2,5]oxadiazole (BMNO) was designed to detect H2S/Cys/GSH using the combination of nitrobenzofurazan (NBD) and benzothiazole fluorophores linked by a facile ether bond. The probe BMNO was developed for simultaneous identification of H2S, Cys and GSH. Noticeably, the color changes (from colorless to light purple, light orange and light yellow) of probe BMNO solutions for sensing H2S, Cys and GSH could be observed by naked eyes, respectively. The probe BMNO exhibited high selectivity and sensitivity for H2S, Cys and GSH showing distinct optical signal with detection limit as low as 0.15 µM, 0.03 µM and 0.14 µM, respectively. The sensing mechanism was clarified by spectrum analysis and some controlled experiments. In addition, these outstanding properties of probe BMNO enabled its practical applications in detection H2S in beer, and in cell imaging for Cys and GSH as well.

Comparison between liraglutide alone and liraglutide in combination with insulin on osteoporotic rats and their effect on bone mineral density.

OBJECTIVES: To compare the therapeutic efficacy of liraglutide (LRG) single drug combined with insulin (Ins) on osteoporosis in rats and its effect on bone mineral density (BMD). A rat model of diabetes combined with osteoporosis was established. METHODS: 40 Sprague-Dawley rats were divided into four groups (blank, control, LRG and LRG+Ins). Serum levels of CrossLaps, procollagen type I N propeptide (PINP), alkaline phosphatase (AKP) and osteocalcin (BGP) were detected by ELISA. Blood glucose was measured by its reaction with glucose oxidase. Serum insulin was analyzed by radioimmunology. Bone calcium and phosphorus contents were also recorded. ELISA was used to detect inflammatory factors. Bone mineral density (BMD) measurement was also performed. RESULTS: BMD of the control group was significantly lower than that of the other three groups (p<0.05) and BMD of the LRG + Ins group was significantly higher than that of the LRG group (p<0.05). The inflammatory factors of the control group were significantly higher than those in the other three groups (p<0.05). The inflammatory factors were negatively correlated with BMD (p<0.05). CONCLUSIONS: liraglutide in combination with insulin for the treatment of diabetes complicated with osteoporosis can reduce blood glucose in vivo, promote production of islet, effectively improve osteoporosis symptoms, increase BMD and reduce the levels of inflammatory factors in vivo.

Structural Design of Two Fluorine-Beryllium Borates BaMBe2(BO3)2F2 (M = Mg, Ca) Containing Flexible Two-Dimensional [Be3B3O6F3]∞ Single Layers without Structural Instability Problems.

Molecular structural design is a compelling strategy to develop new compounds and optimize the crystal structure by atomic-scale manipulation. Herein, two fluorine-beryllium borates, BaMgBe2(BO3)2F2 and BaCaBe2(BO3)2F2, have been rationally designed to overcome the structural instability problems of Sr2Be2B2O7 (SBBO). When relatively large Ba atoms were introduced, the [Be6B6O15]∞ double layers of SBBO were successfully broken, generating flexible [Be3B3O6F3]∞ single layers. Also, the strategy adopted in this work has many implications in understanding the structural chemistry and designing novel optical functional materials in a beryllium borate system.

K8Ce2I18O53: a novel potassium cerium(iv) iodate with enhanced visible light driven photocatalytic activity resulting from polar zero dimensional [Ce(IO3)8]4- units.

Hydrothermally grown iodate, K8Ce2I18O53, featuring polar 0D [Ce(IO3)8]4- units, has shown the highest visible light driven (VLD) photocatalytic activity in metal iodates reported before. The enhanced VLD photocatalytic property results from a synergistic effect between the narrow band gap and polar 0D [Ce(IO3)8]4- units, as confirmed using first principles calculations.

Sacrificial Template Strategy toward a Hollow LiNi1/3Co1/3Mn1/3O2 Nanosphere Cathode for Advanced Lithium-Ion Batteries.

In this work, a hollow LiNi1/3Co1/3Mn1/3O2 (H-NCM) nanosphere cathode with excellent electrochemical performance is developed for lithium-ion batteries. Preparation of the H-NCM nanospheres involves the sacrificial template method, in which carbon nanospheres work as the template and polyvinylpyrrolidone works as an additive. Structural and morphological analyses show that the as-prepared H-NCM nanospheres are highly uniform with diameters of approximately 50 nm and wall thicknesses of 10 nm. Electrochemical tests demonstrate that the H-NCM cathode not only manifests outstanding rate performance in the potential window of 2.5-4.5 V with high reversible specific capacities of 205.6, 194.9, 177.8, 165.9, 151.7, 126.0, and 115.3 mA h g-1 at 0.1, 0.2, 0.5, 1, 2, 5, and 10 C, respectively, but also delivers excellent stability with a capacity retention of 60.1% at 10 C after 2000 cycles. The superior electrochemical performance of the H-NCM cathode can be put down to the distinctive hollow interior structure with thin nanostructured walls, which can synergistically benefit the significantly enhanced rate capability and cycling stability.

Soft-Templated Self-Assembly of Mesoporous Anatase TiO2/Carbon Composite Nanospheres for High-Performance Lithium Ion Batteries.

Mesoporous anatase TiO2/carbon composite nanospheres (designated as meso-ATCCNs) were successfully synthesized via a facile soft-templated self-assembly followed by thermal treatment. Structural and morphological analyses reveal that the as-synthesized meso-ATCCNs are composed of primary TiO2 nanoparticles (∼5 nm), combined with in situ deposited carbon either on the surface or between the primary TiO2 nanoparticles. When cycled in an extended voltage window from 0.01 to 3.0 V, meso-ATCCNs exhibit excellent rate capabilities (413.7, 289.7, and 206.8 mAh g(-1) at 200, 1000, and 3000 mA g(-1), respectively) as well as stable cyclability (90% capacity retention over 500 cycles at 1000 mA g(-1)). Compared with both mesoporous TiO2 nanospheres and bulk TiO2, the superior electrochemical performance of the meso-ATCCNs electrode could be ascribed to a synergetic effect induced by hierarchical structure that includes uniform TiO2 nanoparticles, the presence of hydrothermal carbon derived from phenolic resols, a high surface area, and open mesoporosity.

Superior Sagittal Sinus Obstruction by Giant Meningiomas: Is Total Removal Feasible?

OBJECTIVE: To present our experience with microsurgical technique for patients with giant meningiomas (maximum diameter ≥7 cm) that obstruct the superior sagittal sinus (SSS). METHODS: All patients who were preoperatively diagnosed (between 2010 and 2014) with giant meningiomas involving the SSS in Ward 10 at the Neurosurgery Department of Beijing Tiantan Hospital were enrolled in this study. Patient charts, imaging findings, and outcomes were examined. RESULTS: The study included 6 male and 4 female patients with a mean age of 46.8 ± 10.7 years. The tumor sizes varied from 7 to 12 cm (mean, 8.8 ± 2.0 cm). All patients underwent customized craniotomies, and aggressive surgery for resection of the invaded SSS was performed. Simpson grade I removals were achieved in all cases. No cases of perioperative mortality occurred. Three patients required cranioplasty as a result of a decompressive craniectomy that was performed during the primary surgery. Histologic examinations showed 1 malignant and 9 benign meningiomas. During the follow-up period (mean, 29.0 ± 9.7 months), recurrence/progression occurred in 1 patient, and 1 patient was lost to follow-up. The recent Karnofsky Performance Score was 80 ± 32.3 and was improved in 5 patients and stabilized in 3 patients. In addition, 7 patients lived independently. CONCLUSIONS: The rigorous preservation of cortical veins, draining veins, and eloquent areas should be implemented during the resection of large tumors that obstruct the SSS. Suitable individualized approaches associated with full exposure and low cerebral perfusion pressure levels after surgery are critical for favorable results, and the reconstruction of the SSS may not be necessary.

Clinical, radiological, and pathological features of 33 adult unilateral thalamic gliomas.

BACKGROUND: Unilateral adult thalamic gliomas are rarely reported. In this study, the authors aimed to analyze the clinical, radiological, and pathological features of adult primary unilateral thalamus gliomas (UTGs). METHODS: Clinical data of 33 UTGs in adults who underwent surgical treatment between 2005 and 2014 at the Beijing Tiantan Hospital were collected and retrospectively studied. Follow-up evaluation was performed. RESULTS: This study included 21 males and 12 females with a mean age of 43.1 years. The most common symptoms were headache (75.8%, 25/33 patients) and motor deficits (42.4%, 14/33 patients). Radiological results showed that enhancement was common (90.9%, 30/33 patients) and included cystic appearances in 9 cases (27.3%). All patients underwent maximal safe tumor resection. Gross total resection (GTR) was achieved in 19 cases, subtotal resection (≥80%) in 9 cases, and partial resection (<80%) in 5 cases. Molecular pathology results were available in 15 cases. After surgery, 25 patients received postoperative adjuvant therapy based on the remaining pathology. The median follow-up period of all 33 patients with UTGs was 17 months (1 week~49 months). Twenty-four patients experienced tumor recurrence. The 1-year and 2-year progression-free survival (PFS) rates were 49.0 and 10.2%, respectively. The 1-year and 2-year overall survival (OS) rates were 68.1 and 25.9%, respectively. Survival analyses revealed that several predictive factors were correlated with better prognosis, among which, GTR and tumor with cystic appearances were significantly associated with a longer survival. CONCLUSIONS: Adult UTGs displayed a wide spectrum of clinical features. GTR can be achieved in adult UTGs with acceptable complications and conferred a better prognosis. Tumor with cystic appearance may indicate better prognosis. More patients and longer follow-up periods are needed to further elucidate the biological features of adult UTGs.

Preparation of SnO2 nanowires by solvent-free method using mesoporous silica template and their gas sensitive properties.

In this paper, a facile method was presented to synthesize tin dioxide (SnO2) nanowires by solvent-free method using SnCl2 x 2H2O as precursor and mesoporous silica SBA-15 as the hard template. No solvent was used in the processing. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and N2 adsorption/desorption isotherms. The results indicated that SnO2 nanowires fabricated by this method have a diameter of about 8 nm and a relatively high surface area 73.0 m2/g. The gas sensing properties of SnO2 nanowires were measured. The response and recovery time of this sensor were 6 s and 12 s, respectively. With the concentration of toluene increasing, the response of the sensor doubled increase. Compared with bulk SnO2, SnO2 nanowires showed much higher response to toluene.

A facile two step synthesis of novel chrysanthemum-like mesoporous silica nanoparticles for controlled pyrene release.

Chrysanthemum-like mesoporous silica nanoparticles (MSNs) with large surface areas were successfully synthesized in the presence of ethyl ether by a facile two-step method under mild conditions. Pyrene was chosen to evaluate their drug loading and controlled release properties. The results showed that prepared MSNs exhibited excellent release rate.