An active heterostructure with smart-response material used as "muscle" and inactive material as "skeleton" can deform over time to respond to external stimuli. 4D printing integrated with two-photon polymerization technology and smart material allows the material or characteristic distribution of active heterostructures to be defined directly at the microscale, providing a huge programmable space. However, the high degree of design freedom and the microscale pose a challenge to the construction of micromachines with customized shape morphing.
View Article and Find Full Text PDFThe accumulation of acetate in Escherichia coli inhibits cell growth and desired protein synthesis, and cell density and protein expression are increased by reduction of acetate excretion. Dissolved oxygen (DO) is an important parameter for acetate synthesis, and the accumulation of acetate is inversely correlated to DO level. In this study, the effect of DO levels on glutamate dehydrogenase (GDH) expression was investigated, and then different DO control strategies were tested for effects on GDH expression.
View Article and Find Full Text PDFPhage infection is common during the production of L-threonine by E. coli, and low L-threonine production and glucose conversion percentage are bottlenecks for the efficient commercial production of L-threonine. In this study, 20 antiphage mutants producing high concentration of L-threonine were obtained by atmospheric and room temperature plasma (ARTP) mutagenesis, and an antiphage E.
View Article and Find Full Text PDFIn this study, process engineering and process control were applied to increase the production of l-tryptophan using Escherichia coli Dmtr/pta-Y. Different dissolved oxygen (DO) and pH control strategies were applied in l-tryptophan production. DO and pH were maintained at [20% (0-20 hr); 30% (20-40 hr)] and [7.
View Article and Find Full Text PDFHigh levels of homocysteine (Hcy) is closely associated with the onset of cerebral infarction. The present study aimed to synthesize a novel Hcy probe based on Rhodamine B, named S1-4, a new compound that has not been previously reported. This probe exhibited good linear range under physiological fluid viscosity and pH; it has good selectivity for Hcy, and is able to avoid interference from other amino acids and metal ions.
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