BACKGROUND:Thermoresponsive hydrogels are widely used in bone tissue engineering due to their structural similarity to extracellular matrix and their intelligent temperature sensitivity.OBJECTIVE:To explain the mechanism of temperature-responsive hydrogels producing sol-gel phase transitions,classify them based on their sources,and summarize the applications of various temperature-responsive hydrogels in bone tissue engineering.METHODS:The first author searched for relevant literature on CNKI and PubMed databases from 2000 to 2024,using search terms"hydrogel,thermosensitive hydrogel,bone repair,bone regeneration,bone tissue engineering"in Chinese and English.A total of 70 eligible articles were finally selected for review.RESULTS AND CONCLUSION:The temperature-sensitive mechanism of thermosensitive hydrogels can be divided into negative sensitive and positive sensitive according to different reactions.Its composition is mainly divided into natural polymer and synthetic polymer.Current research has found that in addition to the traditional way of using temperature-sensitive hydrogels as scaffold materials for bone tissue engineering,3D printed scaffolds are also gradually emerging.In addition,thermosensitive hydrogels can also be used in 3D cell culture and drug slow release due to their own characteristics.At present,the development of thermosensitive hydrogels is not perfect enough.There are still problems such as the inability to accurately control the phase transition temperature,sustained release rate,low mechanical strength,and low biodegradability.Therefore,developing thermosensitive hydrogels with more stable properties is still a problem that we should solve at present.

BACKGROUND:Thermoresponsive hydrogels are widely used in bone tissue engineering due to their structural similarity to extracellular matrix and their intelligent temperature sensitivity.OBJECTIVE:To explain the mechanism of temperature-responsive hydrogels producing sol-gel phase transitions,classify them based on their sources,and summarize the applications of various temperature-responsive hydrogels in bone tissue engineering.METHODS:The first author searched for relevant literature on CNKI and PubMed databases from 2000 to 2024,using search terms"hydrogel,thermosensitive hydrogel,bone repair,bone regeneration,bone tissue engineering"in Chinese and English.A total of 70 eligible articles were finally selected for review.RESULTS AND CONCLUSION:The temperature-sensitive mechanism of thermosensitive hydrogels can be divided into negative sensitive and positive sensitive according to different reactions.Its composition is mainly divided into natural polymer and synthetic polymer.Current research has found that in addition to the traditional way of using temperature-sensitive hydrogels as scaffold materials for bone tissue engineering,3D printed scaffolds are also gradually emerging.In addition,thermosensitive hydrogels can also be used in 3D cell culture and drug slow release due to their own characteristics.At present,the development of thermosensitive hydrogels is not perfect enough.There are still problems such as the inability to accurately control the phase transition temperature,sustained release rate,low mechanical strength,and low biodegradability.Therefore,developing thermosensitive hydrogels with more stable properties is still a problem that we should solve at present.

Objective To analyze the characterization of cognitive function in Parkinson's disease with dementia and Alzheimer's disease. Methods Cognitive function was examined in Parkinson's disease with dementia (PDD) patients ( n = 30) , Alzheimer's disease (AD) patients ( n = 30) and healthy elderly control subjects ( n = 60) . Neuropsychological evaluation contained semantic fluency test, phonemic fluency test, action fluency test, objective and action naming tests. Results In PDD group , the score of semantic fluency test is 9. 33 ±2. 78, 6. 17 ± 1.67 of phonemic fluency test and 7.03 ±2. 34 of action fluency test,it is 6.90 ±2.47, 7.87±2.01,8.30±3. 17 of AD group. The score of objective and action naming tests is 36.33 ±3.39, 17.63 ±2. 17 in PDD group,while AD patients is 33.23 ±3.56 and 22.33 ±2.37. The verbal fluency tests and naming tests were impaired in PDD and AD patients compared with the healthy elderly control group (P ＜ 0. 01 ), phonemic fluency, action fluency and action naming were more impaired in PDD patients compared with the AD group , while semantic fluency and objective naming were more impaired in AD patients (P ＜ 0. 01 ). Conclusions Executive function deficit and naming impairment are found in PDD and AD patients, it shows that PDD is characterized by the addition of cortical dysfunction upon a predominant and progressive fronto-subcortical impairment. There is subcortical dysfunction in AD patients.

Objective:To formulate the norm value of auditory verbal learning test(AVLT)in the normal aged in Chinese community.Methods:360 normal old people(55 to 85 years)in city proper of Shanghai were enrolled and evaluated by AVLT,MMSE test of words reading ability and executive ablity,memory self-evaluation and medical history related to cognitive impairment.Results:70% of the normal old people complained of hypomnesia;The age of 70 and 80 was the hinge points of auditory verbal memory decreasing.AVLT had a moderate relation to age,and a lower relation to educational level.Female did better in AVLT than Male.Furthermore,AVLT had a significant relation to MMSE score,a mild relation to memory self-evaluation,and only related to hypertension of all the medical history.The cut off score of short-term recall,long delayed term recall and total AVLT score(-1SD,-1.5SD and-2SD)was listed.Conclusion:Norm value of AVLT is an effective tool of testing memory impairment.