Table of Content

25 January 2022, Volume 50 Issue 1

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Contents



2022, 50(1):  0. 

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Food Science & Technology

Effects of Fermentation and Polyphenol Complex on the Digestibility of Rice Starch



LI Xiaoxi, SHEN Shaodan, LU Ping, et al

2022, 50(1):  1-8.  doi:10.12141/j.issn.1000-565X.210103

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In order to improve the anti-digestibility of rice starch，the change law of digestibility and multi-scale structures of the fermented rice starch-proanthocyanidins complex，including the particle morphology，lamellar structure，crystalline structure，helical structure and short-range ordered structure，were systematically studied with modern analytical techniques and the method of fermentation and interaction with proanthocyanidins.Meanwhile，the molecular mechanism of rice starch anti-digestibility controlling by fermentation and combination with proanthocyanidins was revealed.The results indicates that the rapidly digestible starch and slow digestible starch contents of the fermented rice starch after interacting with proanthocyanidins are decreased，whereas the resistant starch contents are significantly increased.Moreover，the interaction between proanthocyanidins and fermented rice starch can promote the formation of specific ordered structure.And partial proanthocyanidins in the amorphous region can be released to inhibit the action of amylase during the digestion process，which synergisticly reduces the digestibility of fermented rice starch.The results provides foundations for improving the nutritional functions of fermented rice products.

Purification and Emulsifying Properties of Octenyl Succinic Dextrin Ester



HUANG Lixin, DU Peng, YIN Shouwei, et al

2022, 50(1):  9-15.  doi:10.12141/j.issn.1000-565X.210084

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In order to study the purification method of octenyl succinate dextrin ester（OSDE） and its emulsifying properties，this study prepared OSDE with the aqueous phase method by using dextrin and octenyl succinic anhydride as the main raw materials.The product was purified by three methods including ethanol washing method，ion exchange method and membrane separation method.The results show that the purification effect of ion exchange method is the best and is friendly to subsequent determination of substitution degree；the purification effect of membrane separation method was the second；the ethanol washing method shows the worst purification effect.The morphology and group change of OSDE obtained by ion exchange method were analyzed.Scanning electron microscopy（SEM） shows that it is irregular lamellar，with sharp edges and corners，smooth surface，and slightly grooved or spotted corrosion areas；FT-IR analysis shows that the octenyl succinic acid group is successfully introduced into the maltodextrin molecule.After esterification modification，OSDEs viscosity-increasing ability is improved，and the shear thinning property，which is positively correlated with the degree of substitution，is wea-kened；the emulsion stability of the emulsion increases with increase of the degree of substitution of OSDE.Compared with the commonly used emulsifier gum arabic，the soybean oil emulsion of OSDE （DS0.0416） is slightly weaker in emulsification stability，but its rheological properties and microscopic morphology of the emulsion are similar to those of the commonly used emulsifier gum arabic but with lower cost.It shows that OSDE （DS0.0416） has a viable prospect as a substitute for expensive gum arabic in the application of emulsifiers and microcapsule wall materials.

Preparation of Chitosan Coated Liposome Loaded Betanin and Its Antitumor Activity



ZHAO Zhengang LIU Shuang YOU Lijun

2022, 50(1):  16-22.  doi:10.12141/j.issn.1000-565X.210114

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Betanin is a water-soluble pigment with lots of biological activities.However，its stability is low and it is easily degraded under light，high pH，high temperature，enzyme and oxygen.Meanwhile，it is of low bioavailability and it's hard to be absorbed by the body.This study aimed to prepare the chitosan coated nanoliposome loaded betanin （CH-NLP） to improve the stability and bioavailability of betanin.Firstly，Nanoliposome loaded betanin （NLP） was prepared by reverse evaporation method.Then average size，Zeta potential and PDI were measured to determine the optimum concentration of CH-NLP.Meanwhile，CH-NLP，NLP and betanin were evaluated for cytotoxicity and antiproliferative activity against HepG2 cells.Results show that the optimum preparation conditions of NLP are as blow： the mass concentration of lectin is 60 mg/mL；the ratio of betanin and lectin is 1：18；the ratio of lectin and cholesterol is 6：1；ultrasound time is 8 min.The encapsulation efficiency of NLP is （42.67±1.67）%，and the drug loading is（2.63±0.42）%.The optimum concentration of chitosan binding to liposomes is 0.6%.The average size，PDI and Zeta potential are（194.60±4.43）nm，（0.29±0.05），（5.80±0.79）mV，respectively.CH-NLP shows the most potent antitumor activity against HepG2 cells，followed by NLP with the EC₅₀ of（69.46±1.75）and（108.75±2.31）μg/mL，respectively.Betanin possesses the weakest inhibitory effect against HepG2 cells.Chitosan coated liposome as a novel drug delivery system for betanin can significantly enhance its biological activity.

Protective Mechanism of Yeast Hydrolysates Against the Oxidative Injury on Human Umbilical Vein Endothelial Cells



HUANG Yanbo, SUN Weizheng, HOU Yi, et al

2022, 50(1):  23-29.  doi:10.12141/j.issn.1000-565X.210170

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To investigate the protective mechanism of yeast hydrolysate （YH） on human umbilical vein endothelial cell injury induced by H2O2，antioxidant activity of YH was studied.The results show that the median effective concentration （EC50） of YH on DPPH scavenging is 1.85 mg/mL，showing good antioxidant activity.And YH of high-dose （500 μg/mL） can significantly alleviate the cell proliferation inhibition induced by H₂O₂，reduce malondialdehyde （MDA） production and increase the level of superoxide dismutase （SOD），thereby resisting cell oxidative damage of HUVEC caused by H₂O₂.Moreover，transcriptomics sequencing reveals that YH  can significantly up-regulate the expression of genes SOD2 and HMOX1.The research results not only provide basic data for YH to reduce endothelial cell oxidative damage，but also provide a theoretical basis for the application of YH in the fields of antioxidation functional foods and medicine.

Study on the Properties of Rhamnolipids as Biosurfactants



LUO Zhigang YANG Huan QI Liang

2022, 50(1):  30-37.  doi:10.12141/j.issn.1000-565X.210069

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The rhamnolipids components that fermented by Pseudomonas aeruginosa 1.10452 were analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS) in order to explore the potential of rhamnolipids as biosurfactants, and the critical micelle concentration (CMC), emulsifying activity, foam property and antibacterial activity of rhamnolipids were measured. The results of component analysis shows that the rhamnolipids are mainly composed of 9 homologues, and dirhamnolipid is the main component. The critical micelle concentration of rhamnolipids is 80mg/L and its surface activity is better than that of sodium dodecyl sulfate (SDS). Compared with the control group, rhamnolipids shows excellent emulsifying properties on soybean oil (63.75%), liquid para-ffin (65.69%) and n-hexane (52.54%). The foaming ability and foam stability of rhamnolipids are close to that of SDS in pure water, but significantly better than that of SDS in hard water. Furthermore, rhamnolipids exhibits good surface activity and emulsifying activity at different temperature (-20~121℃), ionic strength (0~25 g/L) and pH (6~13). The results of inhibition zone test show that rhamnolipids has strong inhibition ability to Staphylococcus aureus, Escherichia coli and Candida albicans.

Architecture & Civil Engineering

Experimental Study on Mechanical Behavior of New Type Side Joint of CFST Composite Column-Concrete Beam



LING Yuhong, WEN Xingui, ZHENG Wenli, 等

2022, 50(1):  38-49.  doi:10.12141/j.issn.1000-565X.210138

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A new type of joint between concrete-encased concrete-filled steel tubular (CFST) columns and concrete beam was proposed to make wide use of the joint of concrete-filled steel tubular composite column-concrete beam. The tensile force of longitudinal reinforcement at the beam end of the concrete frame was balanced by the ring reinforcement outside the steel tube in the composite column.The longitudinal reinforcement at the beam end was connected with the ring reinforcement in the column in the form of buckle, bending and so on. Six side joints were made and tested under bending monotonic load in order to test the distribution and development of cracks, deformation, failure mode, bearing capacity and ductility of the side joints. And the force transfer mechanism of the anchorage structure of longitudinal reinforcement was revealed. The test results show that, the cracks of the specimens are concentrated in the plastic hinge area at the end of the beam and shows a bending failure mode with sufficient plastic deformation capacity；the ductility coefficient is greater than that of the ordinary reinforced concrete column beam joint；the longitudinal reinforcement at the tensile side of the beam end can yield before the ring bars yield in the column and the specimen reaches the peak load;there is no strain mutation in the longitudinal reinforcement of beam and ring reinforcement of column in the test. The results show that the three connection forms of longitudinal reinforcement and ring reinforcement have similar mechanical performance, and they are all anchored reliably. The test process was simulated by ABAQUS program, which proved the consistence between the calculated results and the test results.

Experimental and Numerical Study on Mechanical Behaviors of Single Curved Cold Bending Insulating Glass Plate



ZHANG Xide LIANG Jinzhi JIANG Jialin

2022, 50(1):  50-58, 68.  doi:10.12141/j.issn.1000-565X.210181

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Cold bending is a new construction method with good application prospects for curved glass curtain wall. To study the mechanical response of cold-bent insulating glass plates, a single curved cold bending experiment was carried out on the insulating glass plates, and the experiment considered the influence of different cold-bent curvatures, glass thicknesses, and cavity thicknesses on the principal stress and inter-layer displacement. Based on the experiment, the finite element numerical simulation of the cold-bent insulating glass plates was carried out. The results show that the principal stress distribution of each surface of the cold-bent insulating glass is uneven；the maximum cold bending principal stress of the glass plate locates on middle point of long side of the convex surface which is most likely to produce damage stress, and the restraint of the spacer bars can cause the displacement of extreme principal stress point on the inner surfaces；the cold bending curvature has the most significant effect on the cold bending principal stress and interlayer displacement of the insulating glass, while the cavity thickness and the glass thickness have smaller effect. The finite element model method and parameters adopted in this study can well simulate the results of the experiment, even though the results is a little conservative. The research results can provide references for the design and construction of single curved cold bend insulating glass.

Study on Pre-tightening Force of Cable Clamp of Self-anchored Suspension Bridge Based on Creep Theory



TANG Mian, CHE Tianxin, SONG Xuming, et al

2022, 50(1):  59-68.  doi:10.12141/j.issn.1000-565X.200740

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The main cable diameter of self-anchored suspension bridge is small and the vertical span ratio is large. In order to study the influence of the pre-tightening force loss caused by creep relaxation of the main cable clamp on the safety of the whole bridge，this study took the main cable clamp of Sanchaji Xiangjiang Bridge in Changsha as the research object, and obtained the empirical formula of the main cable creep changing with initial stress and time based on the metal time hardening creep theory. Considering the influence of radial shrinkage caused by the creep of the main cable and the aging relaxation of the pre-tightening force of the high-strength bolts, the calculation formula of pre-tightening force loss of the high-strength bolts in the cable clamp of the self-anchored suspension bridge during operation was obtained, and the fine finite element model of integration of the main cable and the cable clamp was established by ANSYS for verification. The verification results show that the solution of the calculation formula is slightly larger than the numerical solution by 10~20kN, and the fitting accuracy is good. Therefore, the empirical formula can provide reference for the detection and reinforcement of the pre-tightening force of suspension bridges.

Unified Elasto-Plastic Solution for Cold Regions Tunnel Considering Damage and Non-Uniform Frost Heave



JIANG Wangtao, JIANG Haiqiang, MA Qinguo, et al

2022, 50(1):  69-79, 100.  doi:10.12141/j.issn.1000-565X.210133

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The analysis of elasto-plastic solution can provide a basis for the stability research of cold regions tunnel. Therefore, the elasto-plastic damage mechanics calculation model was established by considering the non-uniform frost heave of surrounding rock. The unified analytical solutions of elasto-plastic stress field and displacement field of cold regions tunnel were derived based on the unified strength theory, and the unified solutions were verified and the parameters were analyzed. The results show that, by neglecting plastic damage and volume frost heave ratio of surrounding rock, the elasto-plastic solution of cold regions tunnel tends to be conservative, and the actual frost heave degree of surrounding rock for cold regions tunnel can be more accurately reflected by considering the non-uniform frost heave. In addition, the potential strength of frozen surrounding rock can be effectively improved by considering the intermediate principal stress effect. The radial stress σf of lining and plastic radius rp of tunnel are significantly influenced by parameters such as damage degree ratio λ/Ef, volume frost heaving ratio ξV, coefficient of non-uniform frost heaving k, unified strength theoretical parameter b, initial ground stress p0 and displacement release coefficient η. Hence, the influence of different parameters on tunnel engineering in cold regions should be reasonably analyzed. The research results can provide theoretical reference for engineering design of cold regions tunnel.

Computer Science & Technology

Handwritten Text Segmentation Method Based on Greedy Snake Algorithm and Radical Recognition



FU Pengbin DONG Aojing YANG Huirong

2022, 50(1):  80-90.  doi:10.12141/j.issn.1000-565X.210028

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A segmentation method based on greedy snake algorithm and radical recognition was proposed to solve the problems of interlacing, adhesion and over-segmentation of Chinese handwritten text. Firstly, the original text segmentation trajectory was established based on the greedy snake algorithm, and the segmentation path was optimized according to the multiple rules. Then, candidate adhesion points were extracted based on the outline and skeleton of adhesion characters, and the gluttonous snake algorithm was used for secondary segmentation. Finally, the radical extraction and recognition of the over-segmentation characters was carried out, and the merging direction was determined based on the structure of Chinese characters. Combined with geometric confidence and recognition confidence, the merging of the over-segmentation characters was completed, and the correct text segmentation result was finally obtained. The effectiveness of the algorithm was verified by the experiment on 1542 lines of handwritten text from a high school test papers of Shaanxi province. The result shows that the accuracy of the segmentation algorithm can reach 82.15%.

Classification Method of Tactile Pressure Footprint Based on Fusion Distribution Graph Network



ZHANG Yan, GAO Zijian, XU Changkang, et al

2022, 50(1):  91-100.  doi:10.12141/j.issn.1000-565X.210128

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With the development of biometric recognition technology, the research of tactile pressure footprint classification has been more and more frequently used, and the traditional classification method is labor-intensive. For tactile pressure footprint classification, the paper proposed a tactile pressure footprint classification method of fusion distribution graph network. Firstly, the convolutional features of the tactile pressure footprint image was extracted through the embedding module and the sample correlation matrix was obtained with the norm-regularization method. Then the fusion correlation matrix between the samples and the label one-hot vector was formed, and feature information was added through the self-attention module. A new feature distribution graph was obtained through the distribution module, and an association matrix between the labeled sample and the unlabeled sample was constructed. Finally, the convolution feature and feature distribution graph of the tactile pressure footprint image were used as the input of the update module to implement the tactile pressure footprint classification. The experimental results show that, compared with the few-shot classification method, this new methods classification accuracy of 5-way1-shot experiments on Mini-Imagenet and Tiered-Imagenet data set reached 71.71% and 74.34%, respectively. Meanwhile, the 5-way 1-shot and 5-way 5-shot experiments on the left and right foot data sets of tactile pressure reached 88.87% and 98.66%, respectively.

Obstacle Avoidance Algorithm for Unmanned Aerial Vehicle Vision Based on Deep Learning



ZHANG Xiangzhu, ZHANG Lijia, SONG Yifan, et al

2022, 50(1):  101-108, 131.  doi:10.12141/j.issn.1000-565X.210096

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In order to solve the obstacle avoidance problem of unmanned aerial vehicle (UAV) based on monocular vision, a quadrotor autonomous obstacle avoidance method based on monocular depth estimation and object detection was proposed.The monocular depth estimation model provides the pixel-level depth information of the obstacle, and the object detection model provides the location information of the obstacles.The depth map and object detection results of a single Red-Green-Blue image were obtained by convolutional neural network (CNN).The region division of the image was based on the object detection results, and the region depth was calculated based on the depth estimation results.The linear velocity and angular velocity of UAV were calculated by the planning algorithm based on the regional depth and regional division results, so as to realize the autonomous obstacle avoidance of UAV.In order to verify the autonomous obstacle avoidance performance of the algorithm, the Parrot Bebop2 UAV was employed to carry out real flight comparison experiments between the proposed algorithm and the direct flight algorithm.The results show that the proposed algorithm can be used for low speed autonomous obstacle avoi-dance of quadrotor.

Reversible Data Hiding Technology for JPEG Images Based on Frequency Selective Expansion



LÜ Wanli TAN Sheng

2022, 50(1):  109-121.  doi:10.12141/j.issn.1000-565X.210062

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Reversible data hiding technology for JPEG images has been widely used.In order to improve the embedding capacity and embedding efficiency of JPEG images in the reversible data hiding process, this paper proposed a reversible data hiding technology based on frequency selective expansion.Firstly, the original image was quantized to generate several DCT blocks, then the DCT blocks were divided into two types to select different embedding positions for embedding based on whether the block contains ±3 and ±4 AC coefficient values.Finally, the embedding distortion of each position in the block were calculated according to the frequency selection strategy.The embedding position was selected and the secret data was embedded according to the ordered frequency of embedded distortion.The experimental results show that the proposed algorithm expands the embedding capacity and reduces the file increase.

Recommendation Model Based on Polarization Relation Representation and Low-Dimensional Data Association Learning



CAI Xiaodong HONG Tao CAO Yi

2022, 50(1):  122-131.  doi:10.12141/j.issn.1000-565X.210082

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The traditional recommendation model based on knowledge graph generally adopts TransH strategy to represent the relations among nodes in the graph, and uses the interactive mode based on feature machine to learn recommendation. This method is not accurate enough to represent the relation among nodes, and often ignores the potential relations among nodes in the low dimensional data. In order to improve the accuracy of recommendation, this research proposed a new representation method based on polarization relation representation, which maps the representation among nodes to unitary space and enriches the effective information of the relations among nodes. In addition, an association learning method for knowledge graph embedding and low dimensional data of recommendation process was designed to deeply mine the rich and detailed relation hided in it, so as to improve the accuracy of recommendation. The experimental results show that the proposed method is effective. Compared with the results of the advanced methods in related fields, Recall Rate and Normalized Discounted Cumulative Gain（NDCG） have significant improvement on Amazon-book, Last-FM datasets.

Biological Engineering

Heterologous Expression of Cutinase and Degradation of Polyethylene Terephthalate with Ultrasound



LOU Wenyong, WU Youquan, GUO Zewang, et al

2022, 50(1):  132-142.  doi:10.12141/j.issn.1000-565X.210145

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Polyethylene terephthalate （PET） is a typical linear thermoplastic resin material，which is widely used in manufacture of fiber，film and beverage bottle.While PET brings many conveniences to human life，its property of difficult degradation has caused serious white pollution and threatened the global environment.In this research，the cutinase LCC was successfully expressed with Escherichia coli BL21 （DE3），and the optimized condition in E.coli BL21（DE3） expression is：inducer isopropyl-β-D-thiogalactopyranoside（IPTG）=0.2 mmol/L，induction temperature =16 ℃，and induction time =20 h.After protein purification process via Ni-affinity chromatography，the enzyme activity of LCC is 320 U/mg.Subsequently，the purified LCC was used to degrade PET with ultrasound，and their reaction conditions were optimized.Under the conditions of reaction temperature= 65℃，pH =8.0，ultrasonic power = 25 W，ultrasonic time=5 h，Km is the smallest and V_max is the largest，the degradation efficiency of LCC with ultrasound is 1.21 times higher than that of untreated，and the product terephthalic acid concentration of （TPA） increases from 0.72 g/L to 0.87 g/L.According to the scanning electron microscopy （SEM），the degradation of PET catalyzed by LCC can be accelerated by ultrasound.The circular dichroism （CD） spectroscopy and fourier transform infrared （FT-IR） spectroscopy show that the α-helix and β-sheets of LCC secondary structure are possibly transformed into random coils with ultrasound.Thus，the degradation of PET catalyzed by LCC can be improved by ultrasonic process.This study provides some theoretical basis for the ultrasonic accelerated degradation reaction and opens up a new idea for the biodegradation of PET.

Production Capacity Improvement of Recombinant Proteins of Pichia pastoris with the SpyTag/SpyCatcher System



HAN Shuangyan LI Jingwen WANG Yuanyuan

2022, 50(1):  143-154.  doi:10.12141/j.issn.1000-565X.210359

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As a kind of methanol-trophic yeast, Pichia pastoris can use methanol as the only carbon source and energy source, and it is one of the widely used expression systems for production of eukaryotic exogenous proteins. However, the utilization and assimilation efficiency of methanol in Pichia pastoris is low, and the methanol of high concentration is toxic to the cell. In the process of metabolizing methanol, the accumulate toxic intermediate metabo-lites such as formaldehyde and formic acid will severely repress cell growth, and limit the synthesis of target proteins.This study designed to construct a substrate channel between the key enzymes in methanol metabolism with multi-enzyme-assembly technology, aiming to reduce the accumulation and diffusion of formaldehyde, improve the flux of the assimilation pathway, enhance the tolerability of Pichia pastoris, and improve Pichia pastoris ability to express foreign protein. Thus Pichia pastoris artificial cell with high methanol utilization can be obtained. In this paper, the feasibility of the multi-enzyme assembly technology—the SpyTag/SpyCatcher system in Pichia pastoris was firstly identified by the bimolecular fluorescence complementation (BiFC) analysis technology. Then alcohol oxidase (AOX) and dihydroxyacetone synthase (DAS) were assembled to form a self-assemble double-enzyme complex with SpyTag and SpyCatcher. On the basis of that, the green fluorescent protein (EGFP) was introduced into the recombinant strain as a reporter protein to analyze the comsumption of methanol for cell growth and the production of recombinant protein. The results show that, when 2% methanol is used as the carbon source, the biomass of the recombinant strain expressing the double-enzyme self-assembly complex is 2.3 times bigger than that of the original strain, and its EGFP fluorescence intensity of per D(600) cell is 4.51 times higher than that of the original strain, and it is 2.76 times of the unassembled strains EGFP fluorescence intensity；the production of EGFP is about 1.52 mg/mL.