Objective:To develop an EGFR-targeting nanobody engineered exosome drug delivery system and evaluate its antitumor efficacy for colorectal cancer.Methods:The HEK293T cell line stably expressing the pan-cancer inhibitor miR-204-5p, previously established by our group, was selected as a tool cell line to prepare miR-204-5p-enriched exosomes. Using metabolic glycoengineering combined with bioorthogonal reaction strategy, these exosomes were modified with the EGFR-specific nanobody 7D12. Western blot, electron microscopy, and dynamic light scattering were used to characterize the engineered exosomes. The tumor target potential of engineered exosomes was evaluated using immunofluorescence and RT-qPCR. The in vitro anti-tumor activities of engineered exosomes were evaluated using cell growth curves, colony formation, Transwell, and apoptosis analyses. The in vivo anti-tumor activity and safety of engineered exosomes were evaluated using a nude mouse xenograft tumor model. Results:The particle size of 7D12-hExo was (116.8±36.8) nm, with a potential of around -10 mV, and there was no significant change compared with the unmodified hExo. Immunofluorescence assay showed that the fluorescence intensity of the hExo group, 7D12-hExo group, and 7D12+7D12-hExo group were 48.4±3.9, 141.0±6.6, and 38.7±3.2 in EGFR + HCT116 cells, respectively. Compared with the hExo group, the fluorescence intensity of HCT116 cells in the 7D12-hExo group was significantly enhanced ( P＜0.05). Compared with the 7D12-hExo group, the fluorescence intensity in HCT116 cells in the 7D12+7D12-hExo group was significantly decreased ( P＜0.05). However, there was no significant difference in the uptake of hExo and 7D12-hExo in EGFR - SW620 colorectal cancer cells. The number of cell clones, invasion, and migration of HCT116 cells in the hExo (204) group was 215.0±14.0, 862.3±61.4, and 1 197.0 ± 36.7, respectively, with an apoptosis rate of (14.1±1.4)%. The number of cell clones, invasion, and migration of HCT116 cells in the 7D12-hExo (204) group was (65.0±15.1), (232.0±27.9), (725.7±32.7), respectively, with an apoptosis rate of (29.3±1.0)%. The 7D12-hExo (204) significantly inhibited the proliferation, invasion, and migration ability of HCT116 cells ( P＜0.05), resulting in promoting the apoptosis of HCT116 cells ( P＜0.05). Nude mouse experiments showed that 7D12-hExo (204) significantly inhibited the growth of tumors transplanted with HCT116 cells, with the inhibition rate being 82.8%. However, there was no significant change in mouse weight, and H&E staining of major organs such as heart, liver, spleen, lung, and kidney did not show any abnormalities. Conclusion:Naturally miR-204-5p-loaded exosomes were successfully modified with nanobody 7D12, which can efficiently deliver miR-204-5p into EGFR + tumor cells, thereby exerting good anti-tumor therapeutic effects.

Objective The biomechanical performance of Ilizarov fixator models with different configurations for humeral shaft defect was compared,so as to provide a biomechanical basis for selecting the appropriate circular external fixation structure for the clinical treatment of humeral shaft defects using Ilizarov technology.Methods Based on CT data of the humerus from a healthy volunteer,the external fixators with three configurations,namely,hybrid frame,semi-ring frame and 90° fan frame were established.The finite element method was used to simulate the displacement and stress distribution under different loading conditions,and the finite element results were validated by biomechanical tests.Results Finite element analysis results:in terms of displacement,under compression,tensile and torque conditions,the displacement of 90° fan model was smaller than that of hybrid and semi-ring models.In terms of stress,the 90° fan model had the smallest displacement under tensile condition.In compression and torque tests,the semi-annular model had the lowest stress.Biomechanical test results:the semi-ring model exhibited the smallest displacement under axial compression,but there was no significant difference between the three models(P＞0.05).Conclusions The semi-ring and 90° fan frames can achieve a similar stability as the traditional hybrid frame through the strategy of'reducing the ring and increasing the stem'.The unilateral structure of the 90° fan frame has the advantages of small size,light weight,and structural stability,as well as a small impact on the shoulder and elbow joints,which makes it more valuable in clinical applications.

Objective To explore the experiences of master degree nursing students and their supervisors under the dual-supervisor system.Methods A phenomenological research was adopted in this study eighteen master degree nursing students,five principle supervisors and four assistant supervisors from our university were selected through purposive sampling for semi-structured interviews between July and September 2023.Data acquired from the interviews was analysed using Colaizzi's method to summarise and extract the themes.Results Three main themes and eleven sub-themes were extracted,including the collaborative framework of the dual-mentor system(discrepancies in the perception of the dual-mentor system between faculty and students,the selection and matching process for associate mentors,the division of responsibilities and collaborative dynamics between primary and associate mentors,student-centered personalized training strategies,context-specific guidance provided by associate mentors,and the extent to which inter-role communication relies on student initiative),the benefits of the dual-mentor system(encompassing diversified academic and professional guidance,as well as integrated theoretical and practical support)and the expectations held by faculty and students regarding the dual-mentor system(refining institutional design and reinforcing accountability,enhancing the support infrastructure for associate mentors,and improving the tripartite communication mechanism among faculty,students,and associate mentors).Conclusion In nursing postgraduate education,the roles and responsibilities within the dual-mentor system can be more clearly delineated,and inter-mentor collaboration should be further strengthened.It is recommended to enhance tripartite communication among faculty,students,and associate mentors to foster the effective implementation and development of the dual-mentor system.

Objective:To evaluate the effects of nasal endoscopy in curettage of large mandibular cyst.Methods:20 cases of large mandibular cyst admitted to Xianyang Hosptial of Yan'an University from January 2022 to December 2023 were included.The curet-tage of mandibular cyst was performed under general anesthesia through intraoral incision by nasal endoscopy-assisted illumination and enlargement of the lesion area during the operation.The application effects were evaluated from the aspects of surgical incision length,nerve injury and cyst recurrence.Results:During operation,the surgical filed of view was clear and the operation was suc-ceeded in all cases.There was no complication in and after the nasal endoscopy-assisted curettage,no cyst recurrence was observed during 1-year follow-up.Conclusion:Nasal endoscopy-assisted curettage of large mandibular cyst is effective and safe.

Objective The biomechanical performance of Ilizarov fixator models with different configurations for humeral shaft defect was compared,so as to provide a biomechanical basis for selecting the appropriate circular external fixation structure for the clinical treatment of humeral shaft defects using Ilizarov technology.Methods Based on CT data of the humerus from a healthy volunteer,the external fixators with three configurations,namely,hybrid frame,semi-ring frame and 90° fan frame were established.The finite element method was used to simulate the displacement and stress distribution under different loading conditions,and the finite element results were validated by biomechanical tests.Results Finite element analysis results:in terms of displacement,under compression,tensile and torque conditions,the displacement of 90° fan model was smaller than that of hybrid and semi-ring models.In terms of stress,the 90° fan model had the smallest displacement under tensile condition.In compression and torque tests,the semi-annular model had the lowest stress.Biomechanical test results:the semi-ring model exhibited the smallest displacement under axial compression,but there was no significant difference between the three models(P＞0.05).Conclusions The semi-ring and 90° fan frames can achieve a similar stability as the traditional hybrid frame through the strategy of'reducing the ring and increasing the stem'.The unilateral structure of the 90° fan frame has the advantages of small size,light weight,and structural stability,as well as a small impact on the shoulder and elbow joints,which makes it more valuable in clinical applications.

Objective To explore the experiences of master degree nursing students and their supervisors under the dual-supervisor system.Methods A phenomenological research was adopted in this study eighteen master degree nursing students,five principle supervisors and four assistant supervisors from our university were selected through purposive sampling for semi-structured interviews between July and September 2023.Data acquired from the interviews was analysed using Colaizzi's method to summarise and extract the themes.Results Three main themes and eleven sub-themes were extracted,including the collaborative framework of the dual-mentor system(discrepancies in the perception of the dual-mentor system between faculty and students,the selection and matching process for associate mentors,the division of responsibilities and collaborative dynamics between primary and associate mentors,student-centered personalized training strategies,context-specific guidance provided by associate mentors,and the extent to which inter-role communication relies on student initiative),the benefits of the dual-mentor system(encompassing diversified academic and professional guidance,as well as integrated theoretical and practical support)and the expectations held by faculty and students regarding the dual-mentor system(refining institutional design and reinforcing accountability,enhancing the support infrastructure for associate mentors,and improving the tripartite communication mechanism among faculty,students,and associate mentors).Conclusion In nursing postgraduate education,the roles and responsibilities within the dual-mentor system can be more clearly delineated,and inter-mentor collaboration should be further strengthened.It is recommended to enhance tripartite communication among faculty,students,and associate mentors to foster the effective implementation and development of the dual-mentor system.

Objective:To evaluate the effects of nasal endoscopy in curettage of large mandibular cyst.Methods:20 cases of large mandibular cyst admitted to Xianyang Hosptial of Yan'an University from January 2022 to December 2023 were included.The curet-tage of mandibular cyst was performed under general anesthesia through intraoral incision by nasal endoscopy-assisted illumination and enlargement of the lesion area during the operation.The application effects were evaluated from the aspects of surgical incision length,nerve injury and cyst recurrence.Results:During operation,the surgical filed of view was clear and the operation was suc-ceeded in all cases.There was no complication in and after the nasal endoscopy-assisted curettage,no cyst recurrence was observed during 1-year follow-up.Conclusion:Nasal endoscopy-assisted curettage of large mandibular cyst is effective and safe.

Objective:To develop an EGFR-targeting nanobody engineered exosome drug delivery system and evaluate its antitumor efficacy for colorectal cancer.Methods:The HEK293T cell line stably expressing the pan-cancer inhibitor miR-204-5p, previously established by our group, was selected as a tool cell line to prepare miR-204-5p-enriched exosomes. Using metabolic glycoengineering combined with bioorthogonal reaction strategy, these exosomes were modified with the EGFR-specific nanobody 7D12. Western blot, electron microscopy, and dynamic light scattering were used to characterize the engineered exosomes. The tumor target potential of engineered exosomes was evaluated using immunofluorescence and RT-qPCR. The in vitro anti-tumor activities of engineered exosomes were evaluated using cell growth curves, colony formation, Transwell, and apoptosis analyses. The in vivo anti-tumor activity and safety of engineered exosomes were evaluated using a nude mouse xenograft tumor model. Results:The particle size of 7D12-hExo was (116.8±36.8) nm, with a potential of around -10 mV, and there was no significant change compared with the unmodified hExo. Immunofluorescence assay showed that the fluorescence intensity of the hExo group, 7D12-hExo group, and 7D12+7D12-hExo group were 48.4±3.9, 141.0±6.6, and 38.7±3.2 in EGFR + HCT116 cells, respectively. Compared with the hExo group, the fluorescence intensity of HCT116 cells in the 7D12-hExo group was significantly enhanced ( P＜0.05). Compared with the 7D12-hExo group, the fluorescence intensity in HCT116 cells in the 7D12+7D12-hExo group was significantly decreased ( P＜0.05). However, there was no significant difference in the uptake of hExo and 7D12-hExo in EGFR - SW620 colorectal cancer cells. The number of cell clones, invasion, and migration of HCT116 cells in the hExo (204) group was 215.0±14.0, 862.3±61.4, and 1 197.0 ± 36.7, respectively, with an apoptosis rate of (14.1±1.4)%. The number of cell clones, invasion, and migration of HCT116 cells in the 7D12-hExo (204) group was (65.0±15.1), (232.0±27.9), (725.7±32.7), respectively, with an apoptosis rate of (29.3±1.0)%. The 7D12-hExo (204) significantly inhibited the proliferation, invasion, and migration ability of HCT116 cells ( P＜0.05), resulting in promoting the apoptosis of HCT116 cells ( P＜0.05). Nude mouse experiments showed that 7D12-hExo (204) significantly inhibited the growth of tumors transplanted with HCT116 cells, with the inhibition rate being 82.8%. However, there was no significant change in mouse weight, and H&E staining of major organs such as heart, liver, spleen, lung, and kidney did not show any abnormalities. Conclusion:Naturally miR-204-5p-loaded exosomes were successfully modified with nanobody 7D12, which can efficiently deliver miR-204-5p into EGFR + tumor cells, thereby exerting good anti-tumor therapeutic effects.

Objective To explore the characteristics of echolalic speech of children with moderate to severe autism spectrum disor-der(ASD)aged three to eight. Methods From January to March,2024,15 minutes rehabilitation course video of five children with moderate to severe ASD aged three to eight were collected in institutional and family settings,respectively.Language sample analy-sis and self-compiled coding were used to analyze the echo speech sample content,structure,and collect their oral language ability.The correlation between the echo speech and case oral language ability was analyzed. Results A total of 235 echoic speech-related speech rounds were recorded.Among them,the ratio of immediacy to de-layed echo speech was 7∶1;one echo speech was found in every two to three speech responses,with average sen-tence length of 2.97 and average word length of 2.23.The frequency of verbs and nouns was high,accounting for 45.03%and 38.48%,respectively;and there were many declarative words and sentences,accounting for 72.58%on average.The type of echo speech structure was the most frequently at the end of the reconstructed discourse,accounting for 29.98%on average.The type,frequency,sentence length,sentence pattern and structure of echoic speech were not significantly different in institutional and family settings.The language ability scores of imita-tion sentence length,word understanding and naming were significantly correlated with the number,frequency,sentence length and sentence type frequency of echoic speech(r>0.881,P<0.01). Conclusion Echoic speech activity in children with moderate to severe ASD aged three to eight shows transsituational stability,and is related with their understanding language and expressive language ability;characterized as instant echo speech,short sentence,the advantage of real words,declarative sentences,often repeat the end of the origi-nal sentence.

OBJECTIVE To study the effects of bergapten in the treatment of liver fibrosis and its mechanism based on serum metabolomics. METHODS Forty mice were divided into normal control group （0.5% carboxymethyl cellulose sodium solution）， model group （0.5% carboxymethyl cellulose sodium solution）， and BP low-dose and high-dose groups （50， 100 mg/kg）， with 10 mice in each group. Except for the normal control group， the other three groups were all treated with carbon tetrachloride to induce liver fibrosis model； they were given relevant medicine/solution intragastrically， once a day， for consecutive 8 weeks. After the last medication， the levels of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） in serum were detected， and liver pathological changes were observed； the expressions of α-smooth muscle actin （α-SMA） and Collagen Ⅰ were detected in liver tissue； the serum of the mice was collected for metabolomics analysis. RESULTS Compared with the model group， serum levels of ALT and AST and protein expressions of α-SMA and Collagen Ⅰ in liver tissue were decreased significantly in BP high-dose and low-dose groups （P＜0.05）， while liver fibrosis was improved significantly. Meanwhile， metabolomics analyses showed that there were a total of 175 serum differential metabolites in the BP high-dose group and model group， of which 18 substances were upregulated and 157 substances were downregulated； the main metabolic pathways involved in bergapten intervention were pyrimidine metabolism， butanoate metabolism， fatty acid synthesis， tyrosine metabolism， β-alanine metabolism， nicotinic acid and nicotinamide metabolism， glutathione metabolism， etc. CONCLUSIONS BP is effective in the treatment of liver fibrosis by regulating pyrimidine metabolism， butanoate metabolism， glutathione metabolism and so on in rats with liver fibrosis.