Direct evidence of cheetah (Acinonyx jubatus) as intermediate host of Toxoplasma gondii through isolation of viable strains.

Toxoplasma gondii causes lifelong infection in most definitive and intermediate hosts. Clinical cases of toxoplasmosis in captive cheetahs have been reported. However, there are few reports of viable T. gondii strains isolated from cheetahs. Here, T. gondii infection was investigated using molecular and serological assays in cheetahs from China. Modified agglutination test (MAT) (cut-off: 1:25) indicated that all six examined cheetahs (n = 6) showed T. gondii antibodies. Toxoplasma gondii DNA was detected in three out of five cheetahs. Two viable T. gondii strains were isolated from the striated muscles of two cheetahs using mice bioassay. They were designated as TgCheetahCHn1 and TgCheetahCHn2. Genetic characterization of DNA derived from tachyzoites was performed using RFLP-PCR of 10 markers. Toxoplasma gondii TgCheetahCHn1 is ToxoDB PCR-RFLP genotype #319, and the alleles of ROP18/ROP5 types were 3/7. TgCheetahCHn2 is ToxoDB genotype #9, and the alleles of ROP18/ROP5 were 3/6. The average survival time of TgCheetahCHn1-infected Swiss mice was 22 ± 1 days (n = 23), and the mice did not have detectable T. gondii-specific antibodies until 117 ± 30 days post-inoculation (n = 8), therefore, TgCheetahCHn1 had intermediate virulence. TgCheetahCHn2 was avirulent for Swiss mice. Few brain tissue cysts (0-50) were observed in the mice inoculated with TgCheetahCHn1 or TgCheetahCHn2. The results provide direct evidence of cheetah as intermediate host of T. gondii.

Generalized Radar Range Equation Applied to the Whole Field Region.

Most terahertz (THz) radar systems can only work in the near-field region, because the THz source power is limited and the size of the target scattered near field is up to tens of kilometers. Such conditions will result in the conventional radar range equation being unsuitable. Therefore, the near-field radar cross section (RCS) formula is given according to the numerical simulation on different targets. By modifying the parameters in the near field, including the gain of radar antennas and the RCS of targets, the generalized radar range equation is proposed. The THz radar working efficiency in the whole range and the simulation of the near-field RCS simulation model were employed to validate its effectiveness. Through comparison with the radar range equation, it can be concluded that the calculation results of the proposed equation are smaller in the near field, and the outcomes in the far field are identical. The proposed generalized radar range equation can be applied to the whole radiation area including the near field and the far field. Furthermore, more complicated real targets are calculated according to the generalized radar range equation and it can be extended from the submillimeter wave band to a much wider band range. Finally, the near-field radar theory is established, which shows its potential application to the radar cross section estimation in the extremely high frequency and fine design of THz radar systems.

Anisodamine alleviates lipopolysaccharide-induced pancreatic acinar cell injury through NLRP3 inflammasome and NF-κB signaling pathway.

Purpose: Anisodamine (An) has anti-inflammatory effects, but its role in acute pancreatitis is still unknown. This study aimed to explore the action mechanism of An pretreatment in lipopolysaccharide (LPS)-induced pancreatic acinar cells, hoping to provide a research basis for the disease treatment.Materials and methods: Pancreatic acinar cells were pretreated with An at different concentrations and then induced by LPS. The viability and apoptosis of the treated cells were measured by Cell Counting Kit-8 and flow cytometry. The releases of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and IL-18 were measured by enzyme-linked immunosorbent assay. The expressions of thioredoxin-interacting protein (TXNIP), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), NOD-like receptor protein 3 (NLRP3), Caspase-1, p65, and inhibitor of kappa B alpha (IκBα) in the treated cells were detected by Western blot and quantitative real-time polymerase chain reaction assay.Results: LPS promoted apoptosis of pancreatic acinar cells, suppressed cell viability, increased TNF-α, IL-1ß, and IL-18 releases and the expression levels of TXNIP, ASC, NLRP3, Caspase-1, p-p65, and p-IκBα, however, such effects of LPS could be alleviated by An pretreatment with the strongest effect when the concentration of An was set at 100 µg/mL. Moreover, overexpressed NLRP3 aggravated the effects of LPS in pancreatic acinar cells, which could be reversed by pretreatment of 100 µg/mL An.Conclusion: An pretreatment attenuated LPS-induced apoptosis and inflammatory response of pancreatic acinar cells through suppressing NLRP3 and inactivating NF-κB signaling pathway, thus, it could be explored as a potential therapy for treating acute pancreatitis.

Feature Point Matching Based on Distinct Wavelength Phase Congruency and Log-Gabor Filters in Infrared and Visible Images.

Infrared and visible image matching methods have been rising in popularity with the emergence of more kinds of sensors, which provide more applications in visual navigation, precision guidance, image fusion, and medical image analysis. In such applications, image matching is utilized for location, fusion, image analysis, and so on. In this paper, an infrared and visible image matching approach, based on distinct wavelength phase congruency (DWPC) and log-Gabor filters, is proposed. Furthermore, this method is modified for non-linear image matching with different physical wavelengths. Phase congruency (PC) theory is utilized to obtain PC images with intrinsic and affluent image features for images containing complex intensity changes or noise. Then, the maximum and minimum moments of the PC images are computed to obtain the corners in the matched images. In order to obtain the descriptors, log-Gabor filters are utilized and overlapping subregions are extracted in a neighborhood of certain pixels. In order to improve the accuracy of the algorithm, the moments of PCs in the original image and a Gaussian smoothed image are combined to detect the corners. Meanwhile, it is improper that the two matched images have the same PC wavelengths, due to the images having different physical wavelengths. Thus, in the experiment, the wavelength of the PC is changed for different physical wavelengths. For realistic application, BiDimRegression method is proposed to compute the similarity between two points set in infrared and visible images. The proposed approach is evaluated on four data sets with 237 pairs of visible and infrared images, and its performance is compared with state-of-the-art approaches: the edge-oriented histogram descriptor (EHD), phase congruency edge-oriented histogram descriptor (PCEHD), and log-Gabor histogram descriptor (LGHD) algorithms. The experimental results indicate that the accuracy rate of the proposed approach is 50% higher than the traditional approaches in infrared and visible images.

Multivariate and Multiscale Approaches for Interpreting the Mechanisms of Nitrous Oxide Emission during Pig Manure-Wheat Straw Aerobic Composting.

Nitrous oxide (N2O) emission during composting causes nitrogen loss and air pollution. The interpretation of N2O emission mechanisms will help to customize composting strategies that mitigate climate change. At pile and particle scales, this study characterized N2O emission-related variables (gases, ions, and microbes) and their correlations during pig manure-wheat straw aerobic composting. Pile-scale results showed that N2O emission mainly occurred in mesophilic, thermophilic, and cooling phases; the nitrification by ammonia-oxidizing bacteria ( AOB) and nitrite-oxidizing bacteria ( NOB) coexisted with the denitrification by denitrificans ( DEN); the major NOB and DEN were Nitrobacter ( NOB_Nba) and Thiobacillus denitrificans ( DEN_Tb), respectively. The mechanisms of nitrification, nitrifier denitrification, and anaerobic denitrification in composting particles were initially visualized by confocal laser scanning microscopy: Betaproteobacteria ( AOB_ Beta) sporadically distributed on the outer area of the particles, NOB_Nba internally attached to AOB_ Beta, and Nitrosomonas europea/ Nitrosomonas eutropha ( AOB_eu) and DEN_Tb concentrated in the interior. Correlation analysis of the variables showed that the distribution area of AOB_eu was proportional to N2O emission ( R2 = 0.84); AOB not only participated in nitrification but also nitrifier denitrification, and N2O formation was mainly from nitrifier denitrification by AOB_eu during the mesophilic-thermophilic phase and from denitrification by AOB_eu and DEN during the cooling phase.

Highly Diastereo- and Enantioselective Synthesis of Chiral Cyclohexylphosphines by Cu-Catalyzed Phosphination-Aldol Cyclization of Ketone-Enamides.

A highly diastereo- and enantioselective phosphinative cyclization of ketone-enamides with secondary diarylphosphines enabled by copper catalysis is reported, providing a range of chiral tertiary cyclohexylphosphines bearing three contiguous stereogenic centers in high yields. This asymmetric phosphination-aldol cyclization protocol can also be extended to desymmetrization of dione-enamides to create four contiguous stereogenic centers in a highly selective manner.

Improved object detection method for unmanned driving based on Transformers.

The object detection method serves as the core technology within the unmanned driving perception module, extensively employed for detecting vehicles, pedestrians, traffic signs, and various objects. However, existing object detection methods still encounter three challenges in intricate unmanned driving scenarios: unsatisfactory performance in multi-scale object detection, inadequate accuracy in detecting small objects, and occurrences of false positives and missed detections in densely occluded environments. Therefore, this study proposes an improved object detection method for unmanned driving, leveraging Transformer architecture to address these challenges. First, a multi-scale Transformer feature extraction method integrated with channel attention is used to enhance the network's capability in extracting features across different scales. Second, a training method incorporating Query Denoising with Gaussian decay was employed to enhance the network's proficiency in learning representations of small objects. Third, a hybrid matching method combining Optimal Transport and Hungarian algorithms was used to facilitate the matching process between predicted and actual values, thereby enriching the network with more informative positive sample features. Experimental evaluations conducted on datasets including KITTI demonstrate that the proposed method achieves 3% higher mean Average Precision (mAP) than that of the existing methodologies.

A hybrid method of frequency-weighted energy operator and power spectrum fusion to detect bearing faults.

The difficulties in early fault diagnosis of bearings mainly include two aspects: first, the initial damage size of the bearing is small, and the abnormal vibration caused by slight damage to the bearing is very weak. Second, vibration signals collected in actual industrial environments always contain strong noise interference. Therefore, traditional diagnostic procedures are not satisfactory. To address these challenges, this work provides a hybrid model combining frequency-weighted energy operator (FWEO) with power spectrum fusion (PSF) to identify weak fault features of bearings and detect different fault types. Different from traditional time-domain signal filtering, PSF is first used to reduce the interference of noise components in the power spectrum, which will not weaken the fault signal components during denoising. Second, the filtered signal is transformed into the time domain and FWEO is employed to further enhance the cyclic fault signal caused by the weak defect of the bearing. Finally, the existence of a fault is identified by observing the squared envelope spectrum of the signal. The effectiveness of the proposed hybrid model is demonstrated through two simulated fault signals and three different experimental fault signals. The results show that the proposed model has high anti-noise performance and robustness and can extract the fault frequency well.

Two viable Toxoplasma gondii isolates from red-necked wallaby (Macropus rufogriseus) and red kangaroo (M. rufus).

Wallabies and kangaroos are susceptible to Toxoplasma gondii. However, little information concerning T. gondii infection in captive macropods is available. Three dead macropods collected from a zoo exhibited no clinical symptoms associated with toxoplasmosis. Heart fluids were tested for T. gondii antibodies using a modified agglutination test. T. gondii DNA samples derived from macropod tissues were tested by Polymerase Chain Reaction. Viable T. gondii were isolated from myocardium of macropods via mouse bioassay. Tissues (brain, lungs, or mesenteric lymph nodes) from T. gondii-positive mice were seeded into Vero cell culture flasks. The virulence of the isolated T. gondii strains was evaluated in Swiss mice. The DNA from T. gondii tachyzoites obtained from cell cultures was characterized by 10 PCR-RFLP markers and the virulence genes, ROP18 and ROP5. T. gondii antibodies were identified in two of the three macropods (Macropod#5 and #7). T. gondii DNA was obtained from the heart and lungs of Macropod#7. Two viable T. gondii strains were isolated from the myocardium of Macropus rufogriseus (Macropod#5) and M. rufus (Macropod#7) via mouse bioassay and designated as TgRooCHn2 and TgRooCHn3, respectively. TgRooCHn2 was ToxoDB genotype#3, and TgRooCHn3 was ToxoDB genotyp#2. Both 104 TgRooCHn2 and TgRooCHn3 tachyzoites had intermediate virulence in mice. M. rufogriseus (Macropod#5) and M. rufus (Macropod#7) may have been in the initial stages of toxoplasmosis, due to a recent T. gondii infection with oocysts. This study is the first to document the T. gondii ToxoDB#3 isolate in macropods. T. gondii infection in captive macropods indicates the urgent need to control the transmission of this parasite in the environment, food and water of zoo animals.

Epidemiology and isolation of viable Toxoplasma gondii strain from macropods.

Wallabies and other marsupials are highly susceptible to Toxoplasma gondii. In this study, 26 macropod samples were collected (8 red kangaroos, 4 Parma wallabies, 8 red-necked wallabies, 5 albino red-necked wallabies and 1 Eastern grey kangaroo), including tissue (n = 9) and serum (n = 17) samples. According to the modified agglutination test (MAT) results (cutoff 1:25), 50% (95% Cl: 32.06-67.94%) of the macropods had T. gondii antibodies. Among them, species, survival state, and sampling date were risk factors for T. gondii susceptibility (P < 0.05). T. gondii DNA was detected in two (cases #14 and #15) of the nine cases obtained from macropod tissues. One viable T. gondii strain (TgRooCHn4) was isolated from an albino red-necked wallaby (Macropus rufogriseus, case #14) via bioassay in mice. TgRooCHn4 belongs to ToxoDB genotype #3, using the 10 multilocus PCR-RFLP markers. The ROP18 and ROP5 gene allele types of TgRooCHn4 were 2/2, which was predicted to be non-lethal to mice. The virulence of TgRooCHn4 tachyzoites was avirulent in mice. Most macropods sampled from Hernan province in 2021 and 2022 were positive with T. gondii infection. A flood occurred in July 2021 in Zhengzhou from Henan province may promote the transmission of T. gondii oocysts. To our knowledge, this is the first T. gondii strain isolated from albino red-necked wallaby. However, further investigation is required to enhance our understanding of the transmission and prevention of toxoplasmosis in sensitive zoo animals.

Isolation and Genetic Characterization of Toxoplasma gondii from a Patas Monkey (Erythrocebus patas) in China.

Many cases of Toxoplasma gondii infection have been reported worldwide in non-human primates (NHPs), especially in captive New World monkeys. However, few studies on toxoplasmosis in Old World monkeys have been conducted. In this study, serological and molecular biological analyses were carried out to look for T. gondii antibodies and T. gondii infection in 13 NHPs from China. T. gondii infection was confirmed in 8 NHP cases. T. gondii antibodies were detected in 1/5 New World monkeys and in 4/7 Old World monkeys. T. gondii DNA was detected in 3/5 New World monkeys and 5/7 Old World monkeys. The one ring-tailed lemur was negative for both antibodies and DNA of T. gondii. The most common clinical manifestations of T. gondii infection were malaise, poor appetite, emaciation, and foamy nasal discharge. The most common histopathological findings were interstitial pneumonia, necrotic hepatitis, necrotizing myocarditis, lymphadenitis, and necrotic splenitis. One viable T. gondii strain was successfully isolated from the myocardium of a patas monkey (Erythrocebus patas) by bioassay in mice. T. gondii tachyzoites were obtained from cell cultures and were designated as TgMonkeyCHn2. The genotype of this strain belongs to ToxoDB genotype #9, and the allele of ROP18/ROP5 gene was 3/6. TgMonkeyCHn2 tachyzoites were avirulent in Swiss mice. To our knowledge, this is the first report of fatal toxoplasmosis in a patas monkey. T. gondii infection in patas monkeys may indicate environmental contamination by oocysts. The patas monkey is a new host record for T. gondii.

Divergent Reassortment and Transmission Dynamics of Highly Pathogenic Avian Influenza A(H5N8) Virus in Birds of China During 2021.

Highly pathogenic influenza A(H5N8) viruses had caused several outbreaks among wild bird and poultry populations across the globe, and strikingly, caused human infection, posing serious public health concerns. In this study, we conducted influenza surveillance in China during 2021 to monitor the evolution of influenza viruses in poultry. A total of 35 influenza viruses were obtained in chickens, ducks, and geese, of which 30 H5N8 viruses, 3 H5N1 viruses, and 2 H5N6 viruses. Phylogenetic analysis suggested all of H5N1, H5N6, and H5N8 isolates were derived from clade 2.3.4.4b H5N8 viruses during 2020/21 season, and notably, the internal genes of H5N1 and H5N6 viruses shared different genetic heterogeneity with H5N8 viruses and had been reassorted with wild bird-origin H5N1 viruses from Europe. By contrast, almost all H5N8 viruses exhibited only one phylogenic cluster with wild bird-origin H5N8 viruses in China and Korea, indicating that H5N8 viruses in China were more stable. Besides, we found that Korea is the main output geographic location in the spread of these H5N8 viruses to northern and eastern China, and especially, the co-circulation of H5N8 viruses occurred within China, with central China acted as a seeding population during the H5N8 epidemic. The statistical support was strong for viral migration from wild birds to chickens and ducks, indicating that 2.3.4.4b poultry-origin H5N8 viruses during 2020-2021 were originated from wild birds. Our findings provide novel insights into evolution and transmission dynamics of H5 subtype influenza viruses among poultry after novel H5N8 viruses invaded China for nearly one year.

Prediction of Peak Overpressure of Charge Enveloped by Polymer Matrix Composite: Theoretical Modeling and Experimental Verification.

This study aimed at elucidating some characteristics of the shock wave overpressure generated by a non-traditional layered charge comprising an inner high-energy explosive and an outer polymer matrix composite. Two models for predicting the peak overpressure (Δpm) of the charge were established, namely, a model based on the initial parameters of the blast wave, and a model considering the weakening of the explosion energy through the introduction of polymer matrix cladding. The overpressure of a typical layered charge was experimentally measured for model validation. It was found that the difference between the Δpm predicted by the two models and the experimental data is less than 15.12% and 14.17%, respectively. The model that was established based on the conservation of energy law, is in best agreement with the experimental data under different cladding/charge mass ratios (αm). The model that was based on the initial parameters of the blast wave obtained a low predicted value when αm was 0.4-0.8, which is attributed to the non-uniformity of the gas-solid mixture during the explosive dispersion stage.

Additional evidence of tigers (Panthera tigris altaica) as intermediate hosts for Toxoplasma gondii through the isolation of viable strains.

Toxoplasmosis is one of the most common zoonotic diseases in the world. Felines excrete Toxoplasma gondii oocysts, which play a key role in the transmission of this protozoon. Pathological diagnoses were performed on four carcasses of captive tigers collected from 2019 to 2021 in China, and T. gondii was surveyed using serology, molecular analysis, and aetiology. Striated muscle samples of the tigers (n = 4) were bioassayed in mice. DNA derived from T. gondii tachyzoites was isolated and characterized using PCR-RFLP. The pathological diagnoses revealed that ageing, declined immune function, liver, and kidney failures caused the deaths in the tigers examined. A modified agglutination test (cut-off: 1:25) revealed that IgG antibodies to T. gondii were 100% (4/4) in the captive tigers. Two viable T. gondii strains (TgTigerCHn3 and TgTigerCHn4) were isolated from tiger striated muscles and seeded on the Vero cell culture for further propagation. The genotypes of TgTigerCHn3 and TgTigerCHn4 were ToxoDB#20 and ToxoDB#2, respectively. The two strains were avirulent for Swiss mice, which matched the ROP18 and ROP5 gene alleles of TgtigerCHn3 (3/4) and TgtigerCHn4 (3/3). Few brain tissue cysts (0-213) were observed in the mice after inoculation with TgTigerCHn3 and TgTigerCHn4. This is the first documented isolation of T. gondii ToxoDB#20 and ToxoDB#2 from tigers. The results provide additional direct evidence of tiger as intermediate hosts for T. gondii. Tigers in the zoos may potentially transmit T. gondii to other animals and humans.

Rhodium/Chiral-Diene-Catalyzed Switchable Asymmetric Divergent Arylation of Enone-Diones.

A rhodium/chiral diene catalytic system is reported for the reaction of enone-diones and arylboronic acids that allows the switchable synthesis of chiral bicyclic products and acyclic products in a controlled manner. The production of bicyclic products containing four contiguous stereocenters is assumed to proceed through the enantioselective arylrhodation of enone-diones with Cs2CO3, forming a rhodium-enolate intermediate, followed by desymmetrization of the diastereotopic diones via aldol cyclization with quantitative diastereoselection and excellent enantiomeric excess. The production of acyclic products is assumed to proceed through the enantioselective hydroarylation of enone-diones with excellent enantiomeric excess in which the aldol cyclization is significantly inhibited by the choice of Et3N as a base. The selectivity for bicyclic products (via tandem arylation-aldol cyclization) and acyclic products (via hydroarylation) is rationalized by the proposed model.

Isolation, genotyping and virulence determination of a Toxoplasma gondii strain from non-human primate from China.

Toxoplasma gondii infects almost all warm-blooded animals, including humans and non-human primates. Many cases of T. gondii infection in non-human primates have been reported worldwide. In this study, 15 monkeys were collected from zoos in Henan Province between 2016 and 2019. A modified agglutination test (MAT) (cut-off: 1:8) showed that 46.7% (7/15) of the heart juices had T. gondii IgG antibody transformation. One viable T. gondii strain was successfully isolated from the myocardium of a rhesus monkey by bioassay in mice. This strain was designated as TgMonkeyCHn1. The DNA of T. gondii tachyzoites was obtained using cell cultures, and the genotype of this strain was determined by PCR-RFLP with 10 markers and the virulence genes ROP5 and ROP18. The genotype and ROP18/ROP5 (3/6) of TgMonkeyCHn1 did not match any known genotypes. In addition, the TgMonkeyCHn1 formed low number of tissue cysts and was non-lethal to mice. To our knowledge, this is the first T. gondii strain isolated from Old World monkeys. Rhesus monkey is a new host record for T. gondii.

Multi-Stream Attention-Aware Graph Convolution Network for Video Salient Object Detection.

Recent advances in deep convolution neural networks (CNNs) boost the development of video salient object detection (SOD), and many remarkable deep-CNNs video SOD models have been proposed. However, many existing deep-CNNs video SOD models still suffer from coarse boundaries of the salient object, which may be attributed to the loss of high-frequency information. The traditional graph-based video SOD models can preserve object boundaries well by conducting superpixels/supervoxels segmentation in advance, but they perform weaker in highlighting the whole object than the latest deep-CNNs models, limited by heuristic graph clustering algorithms. To tackle this problem, we find a new way to address this issue under the framework of graph convolution networks (GCNs), taking advantage of graph model and deep neural network. Specifically, a superpixel-level spatiotemporal graph is first constructed among multiple frame-pairs by exploiting the motion cues implied in the frame-pairs. Then the graph data is imported into the devised multi-stream attention-aware GCN, where a novel Edge-Gated graph convolution (GC) operation is proposed to boost the saliency information aggregation on the graph data. A novel attention module is designed to encode the spatiotemporal sematic information via adaptive selection of graph nodes and fusion of the static-specific and the motion-specific graph embedding. Finally, a smoothness-aware regularization term is proposed to enhance the uniformity of salient object. Graph nodes (superpixels) inherently belonging to the same class will be ideally clustered together in the learned embedding space. Extensive experiments have been conducted on three widely used datasets. Compared with fourteen state-of-the-art video SOD models, our proposed method can well retain the salient object boundaries and possess a strong learning ability, which shows that this work is a good practice for designing GCNs for video SOD.

DL-MRI: A Unified Framework of Deep Learning-Based MRI Super Resolution.

Magnetic resonance imaging (MRI) is widely used in the detection and diagnosis of diseases. High-resolution MR images will help doctors to locate lesions and diagnose diseases. However, the acquisition of high-resolution MR images requires high magnetic field intensity and long scanning time, which will bring discomfort to patients and easily introduce motion artifacts, resulting in image quality degradation. Therefore, the resolution of hardware imaging has reached its limit. Based on this situation, a unified framework based on deep learning super resolution is proposed to transfer state-of-the-art deep learning methods of natural images to MRI super resolution. Compared with the traditional image super-resolution method, the deep learning super-resolution method has stronger feature extraction and characterization ability, can learn prior knowledge from a large number of sample data, and has a more stable and excellent image reconstruction effect. We propose a unified framework of deep learning -based MRI super resolution, which has five current deep learning methods with the best super-resolution effect. In addition, a high-low resolution MR image dataset with the scales of ×2, ×3, and ×4 was constructed, covering 4 parts of the skull, knee, breast, and head and neck. Experimental results show that the proposed unified framework of deep learning super resolution has a better reconstruction effect on the data than traditional methods and provides a standard dataset and experimental benchmark for the application of deep learning super resolution in MR images.

PSR: Unified Framework of Parameter-Learning-Based MR Image Superresolution.

Magnetic resonance imaging has significant applications for disease diagnosis. Due to the particularity of its imaging mechanism, hardware imaging suffers from resolution and reaches its limit, and higher radiation intensity and longer radiation time will cause damage to the human body. The problem is expected to be solved by a superresolution algorithm, especially the image superresolution based on sparse reconstruction has good performance. Dictionary generation is a key issue that affects the performance of superresolution algorithms, and dictionary performance is affected by dictionary construction parameters: balance parameters, dictionary size, overlapping block size, and a number of training sample blocks. In response to this problem, we propose an optimal dictionary construction parameter search method through the experiment to find the optimal dictionary construction parameters on the MR image and compare them with the dictionary obtained by multiple sets of random dictionary construction parameters. The dictionary we searched for the optimal parameters of the dictionary construction training has more powerful feature expressions, which can improve the superresolution effect of MR images.

High-solids enzymatic hydrolysis of ball-milled corn stover with reduced slurry viscosity and improved sugar yields.

BACKGROUND: High-solids enzymatic hydrolysis has attracted increasing attentions for the production of bioethanol from lignocellulosic biomass with its advantages of high product concentration, water saving, and low energy and capital costs. However, the increase of solids content would worsen the rheological properties, resulting in heat/mass transfer limitation and higher mixing energy. To address these issues, ball milling was applied to corn stover prior to enzymatic hydrolysis, and the rheological behaviors and digestibility of ball-milled corn stover under high-solids loading were investigated. RESULTS: Ball milling significantly modified the physicochemical properties of corn stover. The apparent viscosity of slurries at 30% solid loading decreased by a factor of 500 after milling for 60 min, and the yield stress was less than 10 Pa. The dramatic decrease of viscosity and yield stress enabled the hydrolysis process to be conducted in shake flask, and remained good mixing. Meanwhile, the estimated energy consumption for mixing during saccharification decreased by 400-fold compared to the untreated one. The resultant hydrolysate using 10 FPU g-1 solids was determined to contain 130.5 g L-1 fermentable sugar, and no fermentation inhibitors were detected. CONCLUSIONS: The proposed ball milling pretreatment improved rheological behavior and sugar yield of high-solids corn stover slurry. Ball milling enables high-solids slurry to maintain low viscosity and yield stress while obtaining a non-toxic high-concentration fermentable syrup, which is undoubtedly of great significance for inter-unit processing, mixing and downstream process. In addition, the energy input for ball milling could be balanced by the reduced mixing energy. Our study indicates ball milling a promising pretreatment process for industrial bioethanol production.