Enhancing Short Track Speed Skating Performance through Improved DDQN Tactical Decision Model.

This paper studies the tactical decision-making model of short track speed skating based on deep reinforcement learning, so as to improve the competitive performance of corresponding short track speed skaters. Short track speed skating, a traditional discipline in the Winter Olympics since its establishment in 1988, has consistently garnered attention. As artificial intelligence continues to advance, the utilization of deep learning methods to enhance athletes' tactical decision-making capabilities has become increasingly prevalent. Traditional tactical decision techniques often rely on the experience and knowledge of coaches and video analysis methods that require a lot of time and effort. Consequently, this study proposes a scientific simulation environment for short track speed skating, that accurately simulates the physical attributes of the venue, the physiological fitness of the athletes, and the rules of the competition. The Double Deep Q-Network (DDQN) model is enhanced and utilized, with improvements to the reward function and the distinct description of four tactics. This enables agents to learn optimal tactical decisions in various competitive states with a simulation environment. Experimental results demonstrate that this approach effectively enhances the competition performance and physiological fitness allocation of short track speed skaters.

Bifunctional utilization of whey powder as a substrate and inducer for ß-farnesene production in an engineered Escherichia coli.

ß-Farnesene can replace petroleum products as specialty fuel to solve the global fuel energy crisis, but its production by Escherichia coli (E.coli) using glucose and isopropyl ß-D-1-thiogalactopyranoside (IPTG) is costly. Hence, we developed a new strategy to produce ß-farnesene by engineered E.coli strain F13 with bifunctional utilization of whey powder. The utilization of whey powder as a substrate ensured the growth of the strain F13, while whey powder could also replace IPTG to induce the production of ß-farnesene. In shake flasks, ß-farnesene production reached 2.41 g/L by the bifunctional utilization of whey powder as a substrate and inducer, 65.1% higher than that with IPTG and glucose. In the 7 L bioreactor, ß-farnesene production reached 4.74 g/L using whey powder, which was 197% of that in shake flasks. Therefore, this new strategy might be an attractive route to broaden the applications of whey powder and achieve the economical production of ß-farnesene.

Recycling Strategy and Repression Elimination for Lignocellulosic-Based Farnesene Production with an Engineered Escherichia coli.

Farnesene is an important chemical platform for many industrial products, such as biofuels and polymers. We performed high-efficiency utilization of corncobs for ß-farnesene production by separate hydrolysis and fermentation with an optimized Escherichia coli strain. First, we developed a recycling strategy for both corncob pretreatment and cellulose hydrolysis, which saved great amounts of pretreatment reagents and presented a 96.83% cellulose conversion rate into glucose. However, the corncob hydrolysate strongly repressed cell growth and ß-farnesene production, being caused by high-concentrated citrate. Through expressing a heterologous ATP citrate lyase and screening for a suitable expression host, an optimized strain was constructed that produced ß-farnesene at 4.06 g/L after 48 h in a 5 L fermenter, representing an approximately 2.3-fold increase over the initial strain. Therefore, the proposed strategy about the recycling process and repression elimination was successful and suitable for the production of lignocellulosic-based ß-farnesene, which can be further studied to scale up for industrialization.

Utilization of whey powder as substrate for low-cost preparation of ß-galactosidase as main product, and ethanol as by-product, by a litre-scale integrated process.

Whey powder, a by-product of dairy industry, is an attractive raw material for value-added products. In this study, utilization of whey powder as substrate for low-cost preparation of ß-galactosidase as main product and ethanol as by-product were investigated by a litre-scale integrated strategy, encompassing fermentation, isolation, permeabilization and spray drying. Firstly, through development of low-cost industrial culture and fed-batch strategies by Kluyveromyces lactis, 119.30U/mL ß-galactosidase activity and 16.96mg/mL by-product ethanol were achieved. Afterward, an up-dated mathematic model for the recycling permeabilization was established successfully and 30.4g cells sediment isolated from 5L fermentation broth were permeabilized completely by distilled ethanol from broth supernatant. Then ß-galactosidase product with 5.15U/mg from protection of gum acacia by spray drying was obtained. Furthermore, by-product ethanol with 31.08% (v/v) was achieved after permeabilization. Therefore, the integrated strategy using whey powder as substrate is a feasible candidate for industrial-scale implementation.

Wnt/ß-catenin signaling regulates the proliferation and differentiation of mesenchymal progenitor cells through the p53 pathway.

OBJECTIVE: Mesenchymal progenitor cells (MPCs) are found in articular cartilage from normal controls and patients with osteoarthritis (OA). Nevertheless, the molecular mechanisms of the proliferation and differentiation of these cells remain unclear. In this study, we aimed to determine the involvement of Wnt/ß-catenin signaling in regulating the proliferation and differentiation of MPCs. METHODS: MPCs were isolated from the articular cartilage of normal and OA patients. Cells were sorted by immunomagnetic cell separation. Cell proliferation capacity was evaluated using the MTT assay. Toluidine blue staining and immunostaining with anti-collagen II or anti-aggrecan antibodies were used to determine the chondrogenic differentiation capabilities of MPCs. The mRNA and protein expression of target genes were examined by quantitative real-time polymerase chain reaction and Western blotting, respectively. Knock-down of p53 expression was achieved with RNA interference. RESULTS: Most cells isolated from the normal and OA patients were CD105(+) and CD166(+) positive (Normal subjects: CD105(+)/CD166(+), 94.6% ± 1.1%; OA: CD105(+)/CD166(+), 93.5% ± 1.1%). MPCs derived from OA subjects exhibited decreased differentiation capabilities and enhanced Wnt/ß-catenin activity. Inhibition of Wnt/ß-catenin signaling promoted proliferation and differentiation, whereas activation of this pathway by treatment with rWnt3a protein decreased the proliferation and differentiation of normal MPCs. Additionally, Wnt/ß-catenin signaling positively regulated p53 expression, and silencing of p53 increased proliferation and differentiation of MPCs. CONCLUSIONS: Wnt/ß-catenin regulated the proliferation and differentiation of MPCs through the p53 pathway.

Age-related biological characterization of mesenchymal progenitor cells in human articular cartilage.

Adult articular cartilage has a low regeneration capacity due to lack of viable progenitor cells caused by limited blood supply to cartilage. However, recent studies have demonstrated the existence of chondroprogenitor cells in articular cartilage. A critical question is whether these mesenchymal progenitor cells are functionally viable for tissue renewal and cartilage repair to postpone cartilage degeneration. This study was designed to compare the number and function of mesenchymal progenitor cells in articular cartilage collected from human fetuses, healthy adults (aged 28-45 years), and elderly adults (aged 60-75 years) and cultured in vitro. We detected multipotent mesenchymal progenitor cells, defined as CD105+/CD166+ cells, in human articular cartilage of all ages. However, mesenchymal progenitor cells accounted for 94.69%±2.31%, 4.85%±2.62%, and 6.33%±3.05% of cells in articular cartilage obtained from fetuses, adults, and elderly patients, respectively (P<.001). Furthermore, fetal mesenchymal progenitor cells had the highest rates of proliferation measured by cell doubling times and chondrogenic differentiation as compared to those from adult and elderly patients. In contrast, alkaline phosphatase levels, which are indicative of osteogenic differentiation, did not show significant reduction with aging. However, spontaneous osteogenic differentiation was detected only in mesenchymal progenitor cells from elderly patients (with lower Markin scales). The lower chondrogenic and spontaneous osteogenic differentiation of mesenchymal progenitor cells derived from elderly patients may be associated with the development of primary osteoarthritis. These results suggest that measuring cartilage mesenchymal progenitor cells may not only identify underlying mechanisms but also offer new diagnostic and therapeutic potential for patients with osteoarthritis.