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Objective: In order to improve the mushroom drying efficiency and reduce the power consumption, a new type of co-heating and dehumidification drying machine was designed and built. Methods: The drying machine was a closed system, which took the semiconductor refrigeration piece as the main component, with its hot end as heat source for air pre-heating and its cold end as the cold source for water vapor condensation. On the device, the mushroom drying rate at different drying temperatures （55 and 65 ℃） and sample mass （200 and 400 g） were tested. Results: Nine thin layer mathematical drying models were used to simulate the drying rate, which revealed that the Midilli model had a better predict effect than the others. In addition, it was found that the higher drying temperature resulted in a greater color change and a higher shrinkage rate. The comprehensive energy efficiency ratio of the drying machine was 1.96, and the power consumption of drying mushroom was 81.21 MJ/kg. Conclusion: In the experiment, the indexes such as moisture content and color change of dried mushroom met the national standards, and the energy-saving effect was remarkable compared with the traditional electric heating drying machine.

Objective: To obtain the optimal enzyme and preparation process for Schisandra chinensis protein peptides and investigate its in vitro antioxidant activity. Methods: Seven proteases were used to hydrolyze Schisandra chinensis protein. Based on the degree of hydrolysis, free radical scavenging activity, polypeptide yield and content of different hydrolysates of Schisandra chinensis protein and the comprehensive evaluation of molecular weight in SDS-PAGE, the optimal protease was screened. The DPPH free radical scavenging rate was used as the index, and the optimal enzymatic hydrolysis process was determined by single factor test combined with response surface analysis. The scavenging ability of O2-*, *OH, DPPH*, ABTS+*, Fe2+ chelating ability and Fe3+ reducing ability of Schisandrae chinensis protein peptides were analyzed and compared with Schisandra chinensis protein. Results: The optimum enzyme for the preparation of Schisandra chinensis protein peptides was alkaline protease. The optimum enzymatic hydrolysis parameters were as follows: substrate concentration 5%, enzyme-to-substrate ratio 1%, enzymatic hydrolysis time 3 h, enzymatic hydrolysis temperature 55 °C, pH9.0. Under these conditions, the polypeptide content was 88.61%, the degree of hydrolysis was 24.21%, and the DPPH* scavenging rate was 86.96%. The free radical scavenging ability and reducing ability of Schisandrae chinensis protein peptides were better than those of Schisandrae chinensis protein. Conclusion: This study determined the optimum enzyme and hydrolysis process of Schisandrae chinensis protein peptides, and pointed out that Schisandrae chinensis protein peptides had better antioxidant activity in vitro and could be used as a natural antioxidant. [ABSTRACT FROM AUTHOR]

In order to prevent and reduce the disaster losses caused by compound disasters to cities, it was of great theoretical and practical significance to study the exposure degree of chain compound disaster system. Through the research and analysis of the exposure degree of chain compound disaster system, considering the existing research and defining the connotation of the exposure degree of the compound disaster system, the evaluation model and calculation method of the exposure degree of the chain compound disaster system were deduced and established. Taking the rainstorm-landslide disaster chain in Guangdong-Hong Kong-Macao Greater Bay Area as an example for empirical analysis, the evaluation index system of regional disaster chain exposure was screened and constructed from the aspects of population, economy and society. The order relationship analysis and TOPSIS method were used to calculate the single disaster exposure index of rainstorm and landslide in 52 districts and counties in the bay area. Then, the theoretical model of exposure degree of chain compound disaster system and ArcGIS image processing technology were used to obtain the zoning map of rainstorm-landslide disaster chain exposure in the Guangdong- Hong Kong-Macao Greater Bay Area, and the corresponding disaster prevention and mitigation measures were put forward according to the exposure degree attribute of each regional disaster chain. The results showed that the exposure index corresponding to the economically developed areas was significantly higher than that of other regions, and the low exposure were mainly in the relatively backward areas. Among the indicators, population density and GDP per land area account for the main position, which had the highest impact on regional exposure. By the exposure of regional compound disaster systems, reasonable scientific basis and decision-making support could serve for the government and relevant departments, helping the government, urban planners, and the public better understand and respond to disaster risks, thereby reduce the losses and impacts of disasters. [ABSTRACT FROM AUTHOR]

In order to improve the anti-jamming ability and security of the wireless communication system, an index frequency-hopping anti-interference encryption method based on rotation scrambling was designed, which could be simply called encrypted index modulation frequency hopping spread spectrum (EIM-FHSS). Firstly, the wireless secret key was used to control multiple orthogonal frequency hopping patterns to determine the available frequencies at the current moment. The index of the active frequency (the frequency point with the modulation symbol) was used to transmit the bit information. Secondly, the secret key was used to employ scrambling encryption on the mapping table between information bits and the indexes, to ensure the security of the index bits. Finally, constellation rotation encryption was used on the symbols transmitted on the active frequency in the scheme, which ensured the security of symbol bits. Theoretical analysis and simulation results show that the proposed EIM-FHSS method has stronger security and anti-jamming abilities than the traditional IM-FHSS methods. [ABSTRACT FROM AUTHOR]

Neurotransmitters play an important role in nervous system. Temporal and spatial changes of neurotransmitter distribution are crucial to information processing in neural networks. Biosensors that can visually monitor neurotransmitters are one of the vital tools to explore a variety of physiological and pathological activities. This article reviews recent advances in monitoring neurotransmitters with high temporal and spatial resolution, and introduces the latest fluorescent imaging methods for typical neurotransmitters, including glutamate, dopamine, γ-aminobutyric acid and acetylcholine. The article also summarizes the basic principles, advantages and disadvantages of various visually detection methods, and provides systematic suggestions for designing neurotransmitter sensors with high temporal and spatial resolution.

Objective: To analyze the value of MR imaging in diagnosis of intraductal papillary neoplasm of the bile duct (IPN-B)., Methods: Fourteen patients with intraductal papillary neoplasms of the bile duct confirmed by surgical pathology were included in this study. The patients underwent MR routine plain scanning and enhancement scanning (including T1WI, T2WI with fat suppression, FALSH T1WI, and three-phase enhancement scanning), diffusion weighted imaging(DWI) and magnetic resonance cholangiopancreatography (MRCP) before operation. The imaging data were reviewed and analyzed retrospectively in comparison with the surgical and pathological results., Results: In these patients, 7 cases had tumors located in the left lobe, 2 cases had tumors in both the left and right lobes, 2 cases in the hepatic hilum, 2 cases in the common bile duct, and 1 case in both the right lobe and the common bile duct. Solitary or multiple intraductal masses could be found in 12 cases, with 11 cases appeared as papillary masses and one case as flat mass. In the other two cases the tumor was not visible (one case had too many stones, and in another case the tumor was too small). The tumors in the 12 cases showed hypointensity on T1WI and hyperintensity on T2WI. On the dynamic contrast-enhanced MRI, 11 cases showed mild and one showed moderate enhancement in arterial phase, and all the cases showed mildly and gradually delayed enhancement. On DWI, the lesion areas showed high signal intensity in all the cases, and the ADC value of the tumor area (1.697×10(-3)mm(2)/s) was significantly lower than that of the normal bile (3.973×10(-3)mm(2)/s) (t = -10.94, P < 0.05). Twelve cases demonstrated filling defects on primary MRCP coronary thin section images. On 3D-reconstruction MRCP images, 7 cases exhibited diffuse bile duct dilatation with the tumor areas more prominent, 3 cases exhibited aneurysmal bile dilatation, while the rest 4 cases exhibited segmental or lobar bile duct dilatation ( including 2 with invisible tumors ). In the 3 cases with aneurysmal bile dilatation, the multiple directions of MRCP images helped to find the communication between the aneurysmal dilatation and the bile duct. All the cases showed significant proximal bile duct dilatation (the extent of dilatation >100%), and 9 cases also showed distal bile duct dilatation. Bile duct stones were noted in 6 cases, 4 at the tumor area, and the other 2 away from the tumor area. No adjacent tissue invasion and no distal tissue or lymph node metastasis were observed., Conclusion: Intraductal papillary neoplasms of the bile ducts have characteristic imaging appearances on MRI, and MRI is an important method helpful to making correct diagnosis.