一流课程建设背景下高校工程制图课程教学改革路径探究

随着社会经济的发展和科技的进步,高校工程制图课程的教学内容和教学方法需要不断更新和改进,以适应现代产业的需求和学生的学习特点。工程制图课程作为一门重要的基础课程,对学生的专业素养和综合能力培养起着至关重要的作用。而一流课程建设作为高等教育的重要方向之一,为高校工程制图课程的教学改革提供了重要的支撑和动力。如何基于一流课程建设背景更好地改革高校工程制图课程教学,提升学生的学习效果和综合能力,成为当前教育领域亟待解决的问题。对此,通过阐述高校工程制图课程在高校教育体系中的地位,进而分析一流课程建设对高校工程制图课程教学改革的要求,在此基础上探究一流课程建设背景下高校工程制图课程教学改革的路径,以期为高校教育工作者提供有益的参考和借鉴。

miR-30a-5p/PHTF2 axis regulates the tumorigenesis and metastasis of lung adenocarcinoma

Background:Lung adenocarcinoma is a very pervasive histological form of lung cancers,and inhibiting metastasis is crucial for effective treatment.In this investigation,we explored the functional interaction of miR-30a-5p and the putative transcription factor 2 of the homeodomain(PHTF2)in dictating the aggressiveness and metastasis of lung adenocarcinoma.Method:We collected clinical samples to evaluate the expression patterns of miR-30a-5p and PHTF2 in lung adenocarcinoma along with normal tissues.Cellular experiments including cell count kit(CCK)-8 growth assay,apoptosis analysis,migration and invasion examinations were performed to assess the aggressiveness of lung adenocarcinoma cells.Furthermore,we examined tumorigenesis and metastasis in a nude mouse model.Results:MiR-30a-5p exhibited downregulation pattern in lung adenocarcinoma samples.Transfection of miR-30a-5p mimic in lung adenocarcinoma cells resulted in the suppression of malignant characteristics.Notably,the administration of miR-30a-5p mimic also curbed tumorigenesis and metastasis of lung adenocarcinoma cells in animal model.Moreover,PHTF2 was found to be a molecular target of miR-30a-5p.Upregulating PHTF2 counteracted the tumor-suppressive effect of the miR-30a-5p mimic.Conclusion:miR-30a-5p functions as a tumor-suppressive molecule while PHTF2 acts as an oncogenic factor in the development and metastasis of lung adenocarcinoma.Therefore,targeting miR-30a-5p and PHTF2 could be developed into a promising therapeutic approach for inhibiting metastasis in lung adenocarcinoma.

Olefin oligomerization via new and efficient Bronsted acidic ionic liquid catalyst systems

Olefin oligomerization reaction catalyzed by new catalyst systems（a Br？nsted‐acidic ionic liquid as the main catalyst and tricaprylylmethylammonium chloride as the co‐catalyst） has been investigat‐ed. The synthesized Br？nsted acidic ionic liquids were characterized by Fourier transform infrared spectroscopy（FT‐IR）, ultraviolet‐visible spectroscopy（UV）, ^1H nuclear magnetic resonance（NMR）, and ^13 C NMR to analyze their structures and acidities. The influence of different ionic liquids, ionic liquid loading, different co‐catalysts, catalyst ratios（mole ratio of ionic liquid to co‐catalyst）, reac‐tion time, pressure, temperature, solvent, source of reactants, and the recycling of catalyst systems was studied. Among the synthesized ionic liquids, 1‐（4‐sulfonic acid）butyl‐3‐hexylimidazolium hydrogen sulfate（[HIMBs]HSO4） exhibited the best catalytic activity under the tested reaction con‐ditions. The conversion of isobutene and selectivity of trimers were 83.21% and 35.80%, respec‐tively, at the optimum reaction conditions. Furthermore, the catalyst system can be easily separated and reused; a feasible reaction mechanism is proposed on the basis of the distribution of experi‐mental products.

Brφsted-acidic ionic liquids as efficient catalysts for the synthesis of polyoxymethylene dialkyl ethers

Acetalation of formaldehyde(HCHO)with dialkyl formal or aliphatic alcohol to prepare polyoxymethylene dialkyl ethers(RO(CH2O)nR,n≥1)catalyzed by Br?nsted‐acidic ionic liquids has been developed.The correlation between the structure and acidity activity of various ionic liquids was studied.Among the ionic liquids investigated,1‐(4‐sulfonic acid)butyl‐3‐methylimidazolium hydrogen sulfate([MIMBs]HSO4)exhibited the best catalytic performance in the reaction of diethoxymethane(DEM1)with trioxane.The influences of ionic liquid loading,molar ratio of DEM1to HCHO,reaction temperature,pressure,time,and reactant source on the catalytic reaction were explored using[MIMBs]HSO4as the catalyst.Under the optimal conditions of n([MIMBs]HSO4):n(DEM1):n(HCHO)=1:80:80,140°C,and4h,the conversion of HCHO and selectivity for DEM2?8were92.6%and95.1%,respectively.The[MIMBs]HSO4catalyst could be easily separated and reused.A feasible mechanism for the catalytic performance of[MIMBs]HSO4was proposed.

Monitoring forest dynamics in Africa during 2000- 2020 using a remotely sensed fractional tree cover dataset

Africa is covered with extensive woodlands,savannas and rainforests.The tree cover of these biomes has been undergoing substantial changes in recent decades.However,the dynamics of forests in Africa are currently unclear,particularly in the woodlands and savanna areas covered by sparse trees.Here,we assessed the spatio-temporal trend of African forests from 2000 to 2020,using a 250-m resolution fractional tree cover product that can capture the variation of forest density in the widespread mixed vegetation landscapes of the continent.The tree cover trends,interannual change and hotspots of forest gain and loss were evaluated.Results showed that the African forest area increased at a rate of 3.59 million ha/year over the study period,reaching 589 million ha in 2020.Considerable forest gain and loss both occurred in Africa.The net change rate in woodlands’forest area was the fastest(2.28 million ha/year),followed by rainforests(0.80 million ha/year)and savannas(0.34 million ha/year).Hotspots of forest gain were concentrated in the north belt of woodlands and savannas,while forest loss primarily clustered in East and South Africa.This work would help African countries to monitor forest change and promote forest management to achieve the Sustainable Development Goals.

Application of intraoperative O-arm-assisted real-time navigation technique for spinal fixation

This study explored the combined use of the O-arm and real-time navigation during spinal fixation. The clinical data for 60 patients undergoing spinal fixation, at Beijing Tsinghua Chang Gung Hospital between May 5, 2015 and May 1, 2017, were retrospectively analyzed. Pre-, intra-, and postoperative imaging findings were assessed. The patients were classified into the occipitocervical fusion(32 cases) and thoracic/lumbar/sacral spine fixation(28 cases, including 6 cases of percutaneous pedicle screw) groups. Lesion resections were performed microscopically. An O-arm, combined with real-time navigation, was used to assess spinal fixation. Efficacy was evaluated using operative times, X-ray times, screw positioning, and complications. Within the occipitocervical fusion group, 182 screws were placed in the cervical spine and 96 in the occipital bone. However, 6 screws penetrated the bone cortex and were adjacent to the vertebral arteries, based on O-arm three-dimensional imaging; therefore, the precision rate was 96.7%. Within the thoracic/lumbar/sacral spine fixation group, 148 pedicle screws were implanted, with 4 initially outside the vertebral body,yielding a precision rate of 97.3%. Ten percutaneous pedicle screws were implanted and well positioned. O-arm scans were performed 3 times/patient, with an average of 20–30 min/time. Screw implantation times were 5–7 min(cervical spine), 8–10 min(thoracic spine), and 6–8 min(lumbar spine). Intraoperative O-arm scans, combined with real-time navigation technology, allow real-time observation of screw angles and depths, improving the accuracy and safety of posterior screw fixations and reducing the radiation dose and frequency experienced by patients and surgeons.

Surgical resection of a cervical intramedullary schwannoma: A case report and literature review

Schwannomas are the most common type of spinal tumor, and they most commonly occur in intradural extramedullary locations. Intramedullary schwannomas of the central nervous system are very rare and are difficult to diagnose using preoperative imaging. Here, we report a rare, tiny cervical intramedullary schwannoma and review the literature regarding the clinical presentation, magnetic resonance imaging, pathology,and surgical experience associated with this rare tumor type.

Fluorescein sodium use during spinal ependymoma resection

Spinal ependymomas(SEs) are common adult intramedullary tumors; however,determining the absolute boundary between the tumor and the tumor residual may be difficult. We assessed outcomes following the use of fluorescein sodium(FS) during surgical removal of SEs. We performed a retrospective analysis of 112 patients with SEs who were treated at Beijing Tsinghua Changgung Hospital between December 2014 and December 2016. Each patient received intravenous FS(3–4 mg/kg) to determine the SE boundaries during surgery. Tumor removal efficiencies and tumor residuals were assessed using magnetic resonance imaging(MRI) at 10 days and 3 months after surgical recovery; McC ormick's spinal function classification was also performed at the 3-month follow-up. The complete tumor removal rate was 92%(103/112). Ninetyfour patients underwent tumor removal under fluorescent light, which provided distinctive tumor fluorescence. Tumor removal under white light was performed in18 patients; fluorescent images were invisible or indistinctive in these 18 patients. At the 3-month follow-up, sensory function(85.8%(91/106)) and movement(84.3%(86/102)) were improved in patients with pre-surgical dysfunction; urination and defecation functions were improved in 66.7%(16/24). The Mc Cormick spinal cord functional classifications, at the 3-month follow-up, showed significant differences in the percentages of patients with disease classified to each grade(I–IV), compared with preoperative classifications(each, P < 0.05). There was no MRI evidence of tumor relapse or residuals at the 3-month follow-up. FS use during the surgical treatment of SE enables complete tumor removal and detection of tumor residuals.