In cases where a tracheal injury exceeds half the length of the adult trachea or one-third of the length of the child trachea, it becomes difficult to perform end-to-end anastomosis after tracheal resection due to excessive tension at the anastomosis site. In such cases, tracheal replacement therapy is required. Advances in tissue engineering technology have led to the development of tissue engineering tracheal substitutes, which have promising applications. Hydrogels, which are highly hydrated and possess a good three-dimensional network structure, biocompatibility, low immunogenicity, biodegradability, and modifiability, have had wide applications in the field of tissue engineering. This article provides a review of the characteristics, advantages, disadvantages, and effects of various hydrogels commonly used in tissue engineering trachea in recent years. Additionally, the article discusses and offers prospects for the future application of hydrogels in the field of tissue engineering trachea.

Phenylpyruvic acid (PPA) is used as a food and feed additive and has a wide range of applications in the pharmaceutical, chemical and other fields. At present, PPA is mainly produced by chemical synthesis. With the green transformation of the manufacturing industry, biotransformation will be a good alternative for PPA production. The L-amino acid deaminase (PmiLAAD) from Proteus mirabilis has been widely studied for the production of PPA. However, the low yield limits its industrial production. To further enhance the production of PPA and better meet industrial demands, a more efficient synthesis method for PPA was established. In this study, PmiLAAD was heterologously expressed in Escherichia coli. Subsequently, a colorimetric reaction method was established to screen the strains with high PPA production. The semi-rational design of PmiLAAD was carried out, and the obtained triple-site mutant V18 (V437I/S93C/E417A) showed a 35% increase in catalytic activity compared with the wild type. Meanwhile, the effect of N-terminal truncation on the catalytic activity of the V18 mutant was investigated. After the optimization of the whole-cell conditions for the obtained mutant V18-N7, fed-batch conversion was carried out in a 5-L fermenter, and 44.13 g/L of PPA was synthesized with a conversion rate of 88%, which showed certain potential for industrial application. This study lays foundation for the industrial production of phenylpyruvic acid and also offers insights into the biosynthesis of other chemicals.
Escherichia coli/metabolism* ; Proteus mirabilis/genetics* ; Phenylpyruvic Acids/metabolism* ; Protein Engineering/methods* ; Recombinant Proteins/biosynthesis* ; Bacterial Proteins/metabolism*

L-tyrosine is one of the 20 amino acids that make up proteins and is an essential amino acid for mammals, often used as a nutritional supplement. The conventional methods for synthesizing L-tyrosine have some problems such as the production of many by-products, high requirements for production conditions, and environmental pollution. In this study, we designed and constructed a multi-enzyme cascade for the synthesis of L-tyrosine with alanine, glutamate, ammonium chloride, and phenol as substrates. Initially, the sources of glutamate oxidase, alanine aminotransferase, and tyrosine phenol lyase were screened and analyzed, which was followed by the identification of the rate-limiting enzyme in the reaction process. A colorimetric screening method was established, and the rate-limiting enzyme DbAlaA was engineered to enhance its activity by 40.0%. Subsequently, the reaction conditions, including temperature, pH, cell concentration, and surfactant and coenzyme dosages, were optimized. After optimization, the yield of L-tyrosine reached 9.93 g/L, with a alanine conversion rate of 54.90%. Finally, a feed-batch fermentation strategy was adopted, and the yield of L-tyrosine reached 56.07 g/L after 24 h, with a alanine conversion rate of 65.22%. This study provides a reference for the whole-cell catalytic synthesis of L-tyrosine and its industrialization.
Tyrosine/biosynthesis* ; Escherichia coli/metabolism* ; Tyrosine Phenol-Lyase/genetics* ; Multienzyme Complexes/metabolism* ; Fermentation

The emerging and re-emerging arthropod-borne infectious diseases pose a serious threat to global public health security. Field and laboratory studies of arthropods of medical importance are essential and critical for the prevention and control of arthropod-borne infectious diseases. Various institutions or universities in China have been conducting research in the field or laboratory study of arthropods of medical importance, but up to 2023, it is still lacking detailed biosafety guidelines or recommendations that can guide the related work for arthropods of medical importance. In order to proactively address potential biosafety issues in the field or laboratory activities related to arthropods of medical importance, improve the standardization of arthropod biosafety classification, operations, and protection, and ensure the safety of practitioners, an expert consensus on the biosafety recommendation of arthropods of medical importance in field and laboratory has been developed, aiming to guide the future work of arthropods and ensure the national biosafety and biosecurity of China.

Shear thinning is an ideal feature of bioink because it can reduce the chance of blocking. For extrusion based biological printing, bioink will experience shear force when passing through the biological printer. The shear rate will increase with the increase of extrusion rate, and the apparent viscosity of shear-thinning bioink will decrease, which makes it easier to block, thus achieving the structural fidelity of 3D printing tissue. The manufacturing of complex functional structures in tissue trachea requires the precise placement and coagulation of bioink layer by layer, and the shear-thinning bioink may well meet this requirement. This review focuses on the importance of mechanical properties, classification and preparation methods of shear-thinning bioink, and lists its current application status in 3D printing tissue trachea to discuss the more possibilities and prospects of this biological material in tissue trachea.

Objective:To deeply analyze the efficiency of health resource allocation and output insufficiency in Jiangsu Province,and to understand the efficiency and differences of resource allocation in prefecture-level cities,so as to provide references for improving the efficiency of health resource allocation.Methods:The static and dynamic efficiencies of health resource allocation in 13 cities in Jiangsu Province were analyzed using DEA-BCC and Malmquist-DEA,and the distribution of output-deficient cities was plotted using a two-dimensional matrix diagram.Results:From a static perspective,the increase in scale efficiency leads to an increase in overall efficiency,but only one-sixth is fully efficient;from a dynamic perspective,technological progress is a key limiting factor in the increase of total factor productivity;and only 2 cities fall into the zero-output-deficiency region.Conclusion:Health resources in Jiangsu Province are characterized by low overall efficiency,large regional differences,and stagnant technological progress,so it is necessary to improve the efficiency of health resource allocation by emphasizing innovation,promoting technological progress,and classifying and guiding.

Objective:To deeply analyze the efficiency of health resource allocation and output insufficiency in Jiangsu Province,and to understand the efficiency and differences of resource allocation in prefecture-level cities,so as to provide references for improving the efficiency of health resource allocation.Methods:The static and dynamic efficiencies of health resource allocation in 13 cities in Jiangsu Province were analyzed using DEA-BCC and Malmquist-DEA,and the distribution of output-deficient cities was plotted using a two-dimensional matrix diagram.Results:From a static perspective,the increase in scale efficiency leads to an increase in overall efficiency,but only one-sixth is fully efficient;from a dynamic perspective,technological progress is a key limiting factor in the increase of total factor productivity;and only 2 cities fall into the zero-output-deficiency region.Conclusion:Health resources in Jiangsu Province are characterized by low overall efficiency,large regional differences,and stagnant technological progress,so it is necessary to improve the efficiency of health resource allocation by emphasizing innovation,promoting technological progress,and classifying and guiding.

Objective:To deeply analyze the efficiency of health resource allocation and output insufficiency in Jiangsu Province,and to understand the efficiency and differences of resource allocation in prefecture-level cities,so as to provide references for improving the efficiency of health resource allocation.Methods:The static and dynamic efficiencies of health resource allocation in 13 cities in Jiangsu Province were analyzed using DEA-BCC and Malmquist-DEA,and the distribution of output-deficient cities was plotted using a two-dimensional matrix diagram.Results:From a static perspective,the increase in scale efficiency leads to an increase in overall efficiency,but only one-sixth is fully efficient;from a dynamic perspective,technological progress is a key limiting factor in the increase of total factor productivity;and only 2 cities fall into the zero-output-deficiency region.Conclusion:Health resources in Jiangsu Province are characterized by low overall efficiency,large regional differences,and stagnant technological progress,so it is necessary to improve the efficiency of health resource allocation by emphasizing innovation,promoting technological progress,and classifying and guiding.

Objective:To deeply analyze the efficiency of health resource allocation and output insufficiency in Jiangsu Province,and to understand the efficiency and differences of resource allocation in prefecture-level cities,so as to provide references for improving the efficiency of health resource allocation.Methods:The static and dynamic efficiencies of health resource allocation in 13 cities in Jiangsu Province were analyzed using DEA-BCC and Malmquist-DEA,and the distribution of output-deficient cities was plotted using a two-dimensional matrix diagram.Results:From a static perspective,the increase in scale efficiency leads to an increase in overall efficiency,but only one-sixth is fully efficient;from a dynamic perspective,technological progress is a key limiting factor in the increase of total factor productivity;and only 2 cities fall into the zero-output-deficiency region.Conclusion:Health resources in Jiangsu Province are characterized by low overall efficiency,large regional differences,and stagnant technological progress,so it is necessary to improve the efficiency of health resource allocation by emphasizing innovation,promoting technological progress,and classifying and guiding.

Objective:To deeply analyze the efficiency of health resource allocation and output insufficiency in Jiangsu Province,and to understand the efficiency and differences of resource allocation in prefecture-level cities,so as to provide references for improving the efficiency of health resource allocation.Methods:The static and dynamic efficiencies of health resource allocation in 13 cities in Jiangsu Province were analyzed using DEA-BCC and Malmquist-DEA,and the distribution of output-deficient cities was plotted using a two-dimensional matrix diagram.Results:From a static perspective,the increase in scale efficiency leads to an increase in overall efficiency,but only one-sixth is fully efficient;from a dynamic perspective,technological progress is a key limiting factor in the increase of total factor productivity;and only 2 cities fall into the zero-output-deficiency region.Conclusion:Health resources in Jiangsu Province are characterized by low overall efficiency,large regional differences,and stagnant technological progress,so it is necessary to improve the efficiency of health resource allocation by emphasizing innovation,promoting technological progress,and classifying and guiding.