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BACKGROUND:Tissue engineering is considered an ideal treatment for growth plate regeneration.However,most of the current research on regenerative tissue engineering is the traditional scaffold-based strategy.As the limitations of traditional scaffolds are gradually revealed,the research direction is gradually diversifying. OBJECTIVE:To summarize the application of scaffold-based and scaffold-free strategies in the treatment of growth plate cartilage regeneration and their respective advantages and disadvantages. METHODS:The relevant articles were searched from PubMed,Wiley,and Elsevier.The search terms were"growth plate injury,regeneration,tissue engineering,scaffold,scaffold-free,biomimetic,cartilage"in English.The time was limited from 1990 to 2023.Finally,104 articles were included for review. RESULTS AND CONCLUSION:The biomimetic strategy is to reduce the cell composition,biological signals and unique mechanical properties of each region to the greatest extent by simulating the unique organizational structure of the growth plate,so as to build a biomimetic microenvironment that can promote tissue regeneration.Therefore,the design of a biomimetic scaffold is to simulate the original growth plate as far as possible in terms of composition,structure and mechanical properties.Although some results have been achieved,there is still the problem of the unstable regeneration effect.The scaffold-free strategy believes that the limitations of scaffolds will have adverse effects on regenerative therapy.Therefore,the design of scaffold-free constructs relies as much as possible on the ability of cells to generate and maintain extracellular matrix without interfering with cell-cell signals or introducing exogenous substances.However,there are some problems,such as poor stability,low mechanical strength and greater difficulty in operation.Biomimetic strategy and scaffold-free strategy have different emphases,advantages and disadvantages,but they both have positive effects on growth plate cartilage regeneration.Therefore,subsequent studies,whether adopting a biomimetic strategy or a scaffold-free strategy,will focus on the continuous optimization of existing technologies in order to achieve effective growth plate cartilage regeneration therapy.
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Objective@#To understand the trend of changes of hygiene status in the teaching environment among primary and secondary schools in Beijing City during 2016-2020, so as to provide basis for further improving the teaching environment and campus hygiene conditions in primary and secondary schools.@*Methods@#A proportional systematic sampling method covered over 50% of schools selected annually in Beijing from 2016 to 2019, and 34% were selected in 2020. Two representative classrooms were selected from each selected school for testing based on their structure and other factors, with 6 196 classrooms supervised, from 2016 to 2020,1 330,1 312,1 384,1 322,848 classrooms were monitored for each year.@*Results@#From 2016 to 2020, the overall lighting qualification rate of classrooms (lighting coefficient 72.8%, window to floor area ratio 41.8%, rear wall reflectance ratio 42.2%, blackboard reflection ratio 37.4%), the overall qualification rate of average blackboard illumination and uniformity (50.6%, 34.9 %), and the overall qualification rate of desk and chair allocation (58.6%) were all below 80%. The overall qualification rate of per capita classroom area (87.5%), blackboard size (83.2%), average desk illumination ( 80.1% ), average desk illumination and uniformity (82.9%), the distance between lamp and desk (99.1%), carbon dioxide ( 86.6% ), temperature (84.9%), and noise (96.6%) were all above 80%. The following indicators, blackboard size, the distance between lamp and desk, average blackboard illumination, lighting coefficient, blackboard reflectance, rear wall reflectance, carbon dioxide, temperature, and noise ( χ 2=78.38, 9.71, 11.76, 320.59, 37.63, 58.45, 236.45, 1 347.56, 101.97), had statistically significance between years. Among those indicators, the qualified rates of blackboard size, blackboard reflectance, lighting coefficient, and noise had been increasing year by year ( χ 2 trend =69.98, 15.82, 240.02, 5.77) ( P <0.05). The qualified rates of per capita classroom area, window to floor area ratio, and blackboard reflection ratio in primary schools (81.6%, 39.8%, 36.3%) were all lower than those in secondary schools (94.9%, 44.5%, 40.3%) ( χ 2=246.32, 12.03, 10.51, P <0.05). The qualified rates of blackboard size, average blackboard illumination, average blackboard illumination and uniformity, and desk and chair allocation (89.3%, 55.6% , 36.0%, and 60.2%) were all higher than those in secondary schools (75.4%, 44.1%, 33.3%, and 56.5%) ( χ 2=209.33, 78.41, 4.44, 8.22) ( P <0.05). The qualified rates of average desk illumination and uniformity, average blackboard illumination, rear wall reflectance ratio, desk and chair allocation, carbon dioxide, temperature, and noise indicators in urban area (82.9%, 84.1% , 51.9%, 45.0%, 60.9%, 91.2%, 89.5%, 97.8%) were all higher than those in suburban area (77.3%, 81.7%, 49.2%, 39.5%, 56.3%, 82.3%, 80.4%, 95.5%) ( χ 2=31.16, 6.28, 4.36, 16.40, 13.39, 105.29, 98.23, 24.66， P <0.05). The qualified rates of the distance between lamp and desk, lighting coefficient, window to floor area ratio, blackboard size, blackboard reflection ratio, average blackboard illumination and uniformity, and per capita classroom area in urban areas (98.8%, 65.2%, 34.3%, 76.7%, 35.9%, 30.1%, 84.6%) were all lower than those in suburban areas (99.4%, 81.4%, 49.8%, 89.7%, 40.2%, 39.6%, 90.3%) ( χ 2=6.80, 171.67, 132.43, 188.46 , 12.45, 60.28, 44.82) ( P <0.05).@*Conclusions@#The main problems in the teaching environment of schools in Beijing are classroom lighting, as well as desk and chair allocation. The findings suggest technical rationality and operability of relevant standard should be considered when under revision, and standard training and supervision management should be strengthened, with the aim of teaching environment improvement.
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@#Objective To explore the association of Cyclophilin A，cerebral related blood indexes and carotid plaque’s formation and stability as well as cerebral infarction. Methods From December 2017 to December 2018，56 patients with acute cerebral infarction were admitted to cerebral infarction group；72 patients with carotid atherosclerotic plaques but no acute cerebral infraction were regarded as plaque group；40 healthy human who neither suffered from cerebral infarction nor carotid atherosclerotic plaques were divided into non-plague group；The degree of plaque stability in each group was expressed by plaque score. The higher the plaque score，the more unstable the plaque was；The content of CypA were determined by enzyme-linked immunosorbent assay，and the common blood indexes data were collected from the text results of medical records；Carotid artery plaque was detected by carotid artery ultrasound，and the plaque score was determined according to the morphology of carotid artery plaque in ultrasound. Results There were statistically significant differences in CyPA levels between the non-plague group and the non-cerebral infraction group.（P<0.05）. CyPA level was regarded as a risk factor for the development of carotid atherosclerosis plagues（OR=1.002，95%CI 0.824～1.219）. There was no statistical significance between CyPA levels and carotid artery plaque score（the stability of carotid atherosclerotic plaque）in cerebral infarction and non-cerebral infraction group. （P>0.05）. There was an significant difference in carotid atherosclerotic plaque score between the cerebral infarction group and plaque group. （P<0.05）. In cerebral infraction group，the content of fibrinogen and glycosylated hemoglobin were positively correlated with carotid atherosclerotic plaque score and the hemoglobin was negatively correlated with the carotid atherosclerotic plaque score，and these differences were statistically significant. （P<0.05）. Ordinal logistic regression showed that fibrinogen level was regarded as a risk factor for the development of carotid atherosclerosis plagues（OR=8.988，95%CI 3.017～3.422），hemoglobin level was regarded as a protective factor for the development of carotid atherosclerosis plagues（OR=0.936，95%CI 134.031～144.583）. In plaque group，the content of high-density lipoprotein have positive correlation with the carotid atherosclerotic score，and the difference is statistically significant. （P<0.05）. Ordinal logistic regression showed that high-density lipoprotein level was regarded as a protective factor for the development of carotid atherosclerosis plagues（OR=0.052，95%CI 1.237～1.364）. Conclusion The serum content of CyPA was a risk factor for the formation of carotid atherosclerosis plaque，but it was not related to the stability of the plaques. The degree of plaque instability in patients with acute cerebral infarction was significantly increased compared with the patients without cerebral infarction. For patients with acute cerebral infarction，the contents of fibrinogen and glycosylated hemoglobin were negatively correlated with the stability of carotid atherosclerotic plaques，hemoglobin content was positively correlated with the stability of carotid atherosclerotic plaques. Fibrinogen level was regarded as a risk factor for the development of carotid atherosclerosis plagues. Hemoglobin level was regarded as a protective factor for the development of carotid atherosclerosis plagues. For patients without acute cerebral infraction，the content of high-density lipoprotein was positively correlated with the stability of carotid atherosclerotic plaques and was regarded as a protective factor for the development of carotid atherosclerosis plagues.