In recent decades,the advent of coronaviruses has engendered multiple large-scale infectious outbreaks,leading to profound human casualties and posing a significant menace to global public health.At the crux of the coronavirus lifecycle,the assembly and release phases emerge as pivotal processes,necessitating meticulous investigation into the underlying mechanisms.This paper systematically expounds upon the intricate assembly and packaging mechanisms intrinsic to coronaviruses,scrutinizes the diverse release pathways employed by these viruses,and delves into the discourse surrounding targeted antiviral drugs.The comprehensive insights encapsulated in this exposition serve as valuable reference points for formulating effective strategies in the prevention and treatment of coronavirus infections.

Osteotomy around the knee includes medial opening wedge high tibial osteotomy (HTO), lateral closing wedge HTO, lateral opening wedge distal femoral osteotomy (DFO), medial opening wedge DFO, and double-site osteotomy. Osteotomy redistributes the knee joint pressure by correcting the lower limb alignment, which can effectively delay the progression of knee osteoarthritis. Currently, three methods are used to determine the intraoperative osteotomy angle: the pre-drilling method, wedge block insertion method, and angle-guided linkage method. Coronal plane accuracy is evaluated using the hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), and ratio of lower limb weight-bearing line, while sagittal plane accuracy is assessed by measuring the posterior tibial slope (PTS). Individualized osteotomy guide plate can enhance osteotomy accuracy. The preparation process includes: (1) importing low-dose CT data of both lower limbs in DICOM format into reconstruction software to establish a 3D model of both lower limbs; (2) determining the osteotomy plane and distraction angle through threshold segmentation, importing the plate model, and establishing the length and position of each screw; (3) using fused deposition modeling to layer materials through a nozzle to create the 3D object. Individualized osteotomy guide plate in osteotomy around the knee can not only improve the accuracy of surgery, but also reduce the intraoperative fluoroscopy times and the incidence of complications. The operation efficiency and postoperative rehabilitation are better than those of traditional surgery. With the continuous upgrading of new materials and the improvement of design concepts, the accuracy and efficiency of individualized osteotomy guide will be further improved. Future research will focus on improving the degree of personalization of guide plate design and simplifying the manufacturing process.

Objective:To investigate the current situation of occupational hazards in automobile manufacturing enterprises in Shandong Province.Methods:From February to May 2019, the convenience sampling method was adopted to conduct on-site occupational health surveys with 20 automobile manufacturing enterprises in Shandong Province as the survey subjects, to detect the occupational hazard factors in the workplaces and individual exposure levels, and to analyze the occupational health check results of operators.Results:There were 13 small-sized, 4 medium-sized and 3 large-sized enterprises among the 20 automobile manufacturing enterprises. The detection results of benzene and toluene in the workplaces met the occupational exposure limits, and the detection results of welding fumes, manganese and its compounds, and xylene exceed the occupational exposure limits. The maximum short-term exposure concentration ( CSTE) of welding fume in the air of workplaces was 24.23 mg/m 3, and the over-standard rate was 11.0% (16/146) . The maximum time-weighted average concentration ( CTWA) of welding fume of operators is 10.60 mg/m 3, and the over-standard rate was 11.0% (8/73) . The maximum CSTE of manganese and its compounds in the air of workplaces was 0.879 mg/m 3, and the of manganese and its compounds of operators was 0.175 mg/m 3, and the over-standard rate was 5.7% (4/70) . The maximum xylene CSTE in the air of workplaces was 230.00 mg/m 3, and the over-standard rate was 3.9% (2/51) . The maximum xylene CTWA of operators was 70.40 mg/m 3, the over-standard rate was 3.6% (1/28) . Among the 4775 workers exposed to occupational hazards, 38 (0.80%) were suspected of electric welder's pneumoconiosis, 27 (0.57%) were suspected of manganese poisoning and 31 (0.65%) were suspected of chronic low-concentration benzene and benzene series poisoning. The detection rates of suspected occupational diseases among workers in small and medium-sized enterprises were relatively high, 2.86% (30/1048) and 4.51% (51/1132) respectively. There was a statistically significant difference in the detection rates of suspected occupational diseases among the operators of different scale automobile manufacturers ( P<0.05) . Conclusion:The exposure levels of electric welding fumes, manganese and its compounds in welding jobs and xylene exposure levels in spray painting jobsin Shandong Province's automobile manufacturing enterprises are more serious. The supervision and management of occupational hygiene should be strengthened, the working environment should be improved, and the health of welding and painting workers should be protected.

Objective:To investigate the current situation of occupational hazards in automobile manufacturing enterprises in Shandong Province.Methods:From February to May 2019, the convenience sampling method was adopted to conduct on-site occupational health surveys with 20 automobile manufacturing enterprises in Shandong Province as the survey subjects, to detect the occupational hazard factors in the workplaces and individual exposure levels, and to analyze the occupational health check results of operators.Results:There were 13 small-sized, 4 medium-sized and 3 large-sized enterprises among the 20 automobile manufacturing enterprises. The detection results of benzene and toluene in the workplaces met the occupational exposure limits, and the detection results of welding fumes, manganese and its compounds, and xylene exceed the occupational exposure limits. The maximum short-term exposure concentration ( CSTE) of welding fume in the air of workplaces was 24.23 mg/m 3, and the over-standard rate was 11.0% (16/146) . The maximum time-weighted average concentration ( CTWA) of welding fume of operators is 10.60 mg/m 3, and the over-standard rate was 11.0% (8/73) . The maximum CSTE of manganese and its compounds in the air of workplaces was 0.879 mg/m 3, and the of manganese and its compounds of operators was 0.175 mg/m 3, and the over-standard rate was 5.7% (4/70) . The maximum xylene CSTE in the air of workplaces was 230.00 mg/m 3, and the over-standard rate was 3.9% (2/51) . The maximum xylene CTWA of operators was 70.40 mg/m 3, the over-standard rate was 3.6% (1/28) . Among the 4775 workers exposed to occupational hazards, 38 (0.80%) were suspected of electric welder's pneumoconiosis, 27 (0.57%) were suspected of manganese poisoning and 31 (0.65%) were suspected of chronic low-concentration benzene and benzene series poisoning. The detection rates of suspected occupational diseases among workers in small and medium-sized enterprises were relatively high, 2.86% (30/1048) and 4.51% (51/1132) respectively. There was a statistically significant difference in the detection rates of suspected occupational diseases among the operators of different scale automobile manufacturers ( P<0.05) . Conclusion:The exposure levels of electric welding fumes, manganese and its compounds in welding jobs and xylene exposure levels in spray painting jobsin Shandong Province's automobile manufacturing enterprises are more serious. The supervision and management of occupational hygiene should be strengthened, the working environment should be improved, and the health of welding and painting workers should be protected.

OBJECTIVE: To observe the conditions of sub-chronic crotonaldehyde exposure-induced pulmonary inflammation,oxidative stress and apoptosis in male rats,and to explore the related mechanisms. METHODS: The specific pathogen free Wistar male rats were randomly divided into control group,low-,medium-and high-dose crotonaldehyde groups,with 10 rats in each group. Rats were treated with crotonaldehyde at the concentrations of 0. 0,2. 5,4. 5 and 8. 5 mg/kg body weight by intra-gastric administration,once per day for 120 consecutive days. After the end of treatment,rats were sacrificed,the lungs were weighed and histopathological examination was performed. The levels of malondialdehyde( MDA),superoxide dismutase( SOD) and glutathione peroxidase( GSH-Px) in the serum of rats were determined by colorimetry. The relative expression of reactive oxygen species in lung tissues was detected by fluorescence probe. The apoptosis rate was detected by Tunel staining. The relative expression of B-cell lymphoma( Bcl)-2,Bcl-2 associated X protein( Bax) and cysteine aspartic acid protease-3( Caspase-3) proteins in lung tissue was detected by western blotting.RESULTS: The body weight of the rats in the high-dose group began to decrease after 30 days of exposure( P < 0. 05),and the body weight in the low-and medium-dose groups began to decrease at 90 days exposure( P < 0. 05),when compared with that of the control group at the same time. The body weight of the high-dose group was lower than that of the low-and medium-dose groups began to decrease at 90 days exposure( P < 0. 05). After exposure,the lung tissue of the three doses groups showed different degrees of inflammatory change in a dose-effect relationship. The level of serum MDA in rats increased with the treatment of crotonaldehyde( P < 0. 01). The activities of serum SOD and GSH-Px decreased with the treatment of crotonaldehyde( P < 0. 01). The relative expression of ROS and apoptosis rate in rat lung tissue increased with the treatment of crotonaldehyde( P < 0. 01). The relative expression of Bcl-2 protein and the ratio of Bcl-2/Bax in the lung tissue of rats decreased with the treatment of crotonaldehyde( P < 0. 01). The relative protein expression of Bax and Caspase-3 increased with the treatment of crotonaldehyde( P < 0. 01). CONCLUSION: Crotonaldehyde sub-chronic exposure can cause apoptosis in lung tissue by altering the oxidative balance,leading to inflammatory pathological changes in the lung.

Osteochondral defects caused by various factors are still difficult clinical problems. With the development of tissue engineering, the strategies and methods for repairing osteochondral defects in the past decade have made great progress, and some osteochondral tissue stratified stent products have gradually entered the clinical trial stage.. The related articles on tissue engineering for the treatment of osteochondral defects were retrieved by searching databases with key words osteochondral defects, cartilage repair and hierarchical scaffolds. This paper discussed the research status of hierarchical scaffolds in osteochondral tissue engineering during recent five years. In this work, the classification of hierarchical scaffold including monophasic scaffolds, bilayered scaffolds, multilayered scaffolds and gradient scaffolds, are summarized by comparing different experiment researches. Furthermore, the advantages and disadvantages of different types of hierarchical scaffolds were introduced through analyzing relevant studies. Monophasic scaffolds can support the adhesion and proliferation of osteoblasts and chondrocytes, but lack the inherent stratified structure features required for osteochondral regeneration.. Bilayered scaffolds consist of a chondral layer and subchondral layer which base on the biocompatibility of monophasic scaffolds. Biphasic scaffolds are significantly better than monophasic scaffolds in simulating natural cartilage, but the interface between chondral and subchondral layer is poor binding. Compared with bilayered scaffold, trilayered scaffolds are added with an intermediate layer which simulates the calcification of normal cartilage between the two layers, so as to obtain better connection of the bone and cartilage layer. Unlike hierarchical scaffolds, gradient scaffolds provide a gradient connection between the layers, which is more similar to the native osteochondral tissue. In the past five years, the development of osteochondral layered scaffolds mainly depended on the novel structure and fabrication methods of scaffolds. However, correlational clinical studies are quite few. Further high quality and large clinical studies are still required.

Objective To investigate the clinical efficacy of radiofrequency surgical therapy combined with ozone for patients with discogenic low back pain. Methods The clinical data were collected in 120 patients treated with radiofrequen?cy and ozone for lumbar disc herniation at Tianjin Hospital from October 2013 to October 2015. Pain visual analogue scale (VAS) was used to patients at preoperative and postoperative 1 week, 1, 3, 6 and 12 months. Health survey (SF-36) score was used at preoperative and postoperative six months. The efficacy was evaluated by MacNab curative effect evaluation. Re?sults The preoperative VAS score was (7.02±0.64) points. The postoperative VAS scores were (3.13±0.32) points, (2.11± 0.67) points,(2.62±0.89) points,(2.37±0.34) points and (2.31±0.50) points at one week, one month, three months, six months and twelve months, respectively. The VAS scores were significantly decreased after surgery (P<0.05). Preoperative SF-36 score was (48.32 ± 7.46) points, which reached to the (82.03 ± 5.89) points six months after surgery (P < 0.05). After six months, the fineness rate reached to 89.17%evaluated by MacNab curative effect evaluation. Conclusion Radiofrequency combined with ozone treatment is an effective and reliable method for discogenic low back pain.

As internal protein elements , inteins are self-excised from their host protein and catalyze ligation of exteins with a peptide bond .They are widely found in all the three domains of the biological kingdom , and in viral proteins .Intein-mediated protein splicing is a posttranslational autocatalytic process that does not require auxiliary enzymes or cofactors . Protein splicing involves four intramolecular reactions and a small number of key catalytic residues in the intein and exteins . The development of expressed protein ligation ( EPL ) and protein trans-splicing ( PTS ) is assisted by inteins and protein splicing.This review introduces the biosynthesis of backbone-cyclized peptides libraries , and describes the applications of cyclic polypeptides and their prospective applications in the future .

Objective To explore the angiogenesis&neovascularization effects of naringin treatment in ovariectomized rats’fracture healing. Methods Upper 1/3 transverse tibial fracture model 4 weeks later after ovariectomized were estimated and randomly divided into the naringin group and control group. Microfil perfusion technique was used to analysis the angiogene?sis situation at two weeks after bone fracture. HE staining was used to evaluate the level of angiogenesis&neovascularization of tis?sue from histological point of view. The relative expression of VEGF in the callus was identified by real?time polymerase chain re?action. Immunohistochemical technique was used to observe the vessel endothelial growth factor?2 in the callus of the two groups. Maximum fracture load was tested by three?point bend test. Results The vascular volume and vascular density were more in nar?ingin group than control group. The HE staining of the 2 week group slices shows that the VA, VN2 of the unit of high magnifica?tion vision of the naringin group was significantly larger compared to the control group. Real?time PCR revealed that the compara?tive expression of VEGF is more in naringin group than in control group; the positive number of VEGFR?2 is more in naringin group than in control group. Naringin can promote the maximum load of the callus. Conclusion Naringin can promote ovariecto?mized rats’angiogenesis&neovascularization in the early process of fracture healing. It may be act on the signaling pathway of VEGF/VEGFR?2.

Estrogen is involved in the process of postmenopausal osteoporosis, and the main functional cells are osteoclasts. However, the mechanism of estrogen on the osteoclasts is not yet fully understood. Here we demonstrate the effects of estrogen on osteoclasts in three aspects: morphology and structure, apoptosis of osteoclasts and differentiation of preosteoclasts, which give an overall explanation for effects of estrogen on osteoclasts.