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 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 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 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 investigate the impact of exogenous lactate on the replication of dengue virus type 2 (DENV-2) in Raw264.7 cells, mouse bone marrow-derived macrophages (BMDMs) and THP-1 cells and explore its association with cell activation.Methods:BMDMs from BALB/c mouse bone marrow were prepared and evaluated by flow cytometry to detect the proportion of F4/80 + CD11b + cells. Glucose transporter type 1 (GLUT1), hexokinase 2 (HK2), and monocarboxylate transporters 4 (MCT4) expression at mRNA level in BMDMs at different time points after DENV-2 infection were measured by qRT-PCR. The content of lactate in the culture supernatants was quantified via colorimetric assay. CCK-8 assay was used to evaluate the impacts of different concentrations of lactate on the viability of Raw264.7 cells, BMDMs, and THP-1 cells. qRT-PCR was used to detect the expression of DENV-2 E gene, TGF-β, CD86, retinoic acid-inducible gene Ⅰ (RIG-Ⅰ), IFN-β, interferon-stimulated gene 15 (ISG15), and ISG56 at mRNA level in cells infected with DENV-2 at different MOIs in the presence of different concentrations of lactate. Meanwhile, flow cytometry was used to analyze the expression of CD86 and CD206. Results:The percentage of BMDMs was (87.53±1.66)%. GLUT1 expression at mRNA level exhibited a decrease in BMDMs at 24 h after DENV-2 (MOI=3) infection following a transient increase at 12 h ( P<0.05), while HK2 expression at mRNA level was higher that than in blank control and inactivated DENV-2 infection groups at 12, 24, and 36 h ( P<0.01). Besides, there was an increase in both MCT4 mRNA level and the content of lactate in culture supernatants at 24 h after DENV-2 (MOI=1.5) infection ( P<0.05). The viability of the three types of cells remained above 80% when the concentration of lactate was 31.25 mmol/L. Lactate at the concentration of 35 mmol/L increased the expression of the DENV E gene at mRNA level in DENV-2-infected BMDMs at MOI=1 or MOI=2 ( P<0.05). Besides, it promoted the expression of DENV E gene at mRNA level in Raw264.7 and THP-1 cells ( P<0.001) as well as the expression of CD163, TGF-β, RIG-Ⅰ, IFN-β, ISG15 and ISG56 at mRNA level in BMDMs at MOI=1.5, but inhibited the expression of CD86 at mRNA level in BMDMs ( P<0.05). It also up-regulated CD206 protein expression ( P<0.01) and down-regulated CD86 protein expression ( P>0.05) in BMDMs. Conclusions:Exogenous lactate enhances DENV-2 replication in both human- and murine-derived macrophages and that might correlate with M2 macrophage polarization.

Objective To construct the evaluation index of physical restraint nursing quality for neurosurgical patients,which can guide nurses'clinical practice and continuously improve work flow and quality.Methods Under the guidance of three-dimensional quality structure model,the evaluation index of nursing quality of physical restraint in neurosurgery patients was established by reviewing literature,interviewing experts and using Delphi expert correspondence.Results The effective recovery rate of three rounds of expert enquiry was 100％,the expert authority coefficient was＞0.9,the first and second coordination co-efficients were 0.126 and 0.094(P＜0.001),and the final evaluation index included 3 first-level indicators and 31 second-level indicators.Conclusion The established evaluation indexes are scientific,standardized and comprehensive,which can guide the nursing quality of neurosurgery patients with physical restraint.