ObjectiveTo develop and verify a reversed-phase high performance liquid chromatography(RP-HPLC)method for the determination of residual amount of trifluoroacetic acid(TFA)in human interferon alpha 2b(hIFNα2b)stock solution,and preliminarily apply the method.MethodsThe conditions of liquid chromatography were as follows:ZORBAX300SB-C18 column(4. 6 mm × 250 mm,5 μm);mobile phase:0. 08% phosphoric acid(pH 3. 0)+ 5. 0% methanol solution;detection time:6 min;flow rate:0. 8 mL/min;column temperature:35 ℃；UV wavelength:210 nm;injection volume:20 μL;isocratic elution. The system adaptability,linearity,specificity,accuracy,precision,limit of quantitation(LOQ),limit of detection(LOD)and durability of the method were verified. The TFA residues in three batches of hIFNα2b stock solution samples were determined by the developed method and composite column Comixsil ACRP(100 mm × 4. 6 mm,5 μm).ResultsThe linearity of TFA was good in the range of 10-300 μg/mL(R2= 0. 998 4). The average spike recovery rate was 101. 8% and RSD was 2. 68%. The RSDs of repeatability and intermediate precision verification were 0. 46% and0. 45%,respectively. The LOQ was 10 μg/mL,and the LOD was 2 μg/mL. The slight fluctuation of pH of organic solvent,buffer salt and temperature of column under the specified conditions had no obvious influence on the detection results,and the peak area was affected when the detection wavelength changed. In addition,TFA residues were not detected in three batches of hIFNα2b stock solution by two methods.ConclusionThe developed RP-HPLC method has good system adaptability,specificity,accuracy,precision and durability,and can be used for the determination of TFA residues in hIFNα2b stock solution.

BACKGROUND:Searching for a porous three-dimensional (3D) scaffold holding good porosity, mechanical property and biocompatibility has become a hot spot, in which, 3D printing technology also plays apart. OBJECTIVE:To prepare silk fibroin/col agen scaffolds using 3D printing technology and detect its performance. METHODS:Silk fibroin/col agen scaffolds were constructed using 3D printing technology, and the silk fibroin/col agen mass ratio was 4:2 (group A) and 4:4 (group B), respectively. The porosity, water absorption expansion rate, mechanical properties and pore size of the composite scaffolds were detected. The passage 3 rat bone marrow mesenchymal stem cel s were seeded onto the two scaffolds. The cel proliferation was detected using MTT assay at 13 days of culture, and the cel morphology was observed by hematoxylin-eosin staining and scanning electron microscope at 14 days of culture. RESULTS AND CONCLUSION:The porosity, pore size, and water absorption expansion rate of group A were significantly larger than those of group B (P<0.05), while the elasticity modulus showed no significant difference between groups. Bone marrow mesenchymal stem cel s on the two scaffolds increased gradual y with time, especial y in the group A (P<0.05). Abundant cel s distributed evenly in the group A, while few cel s distributed unevenly in the group B. These results suggest that the 3D printed scaffolds composed by silk fibroin/col agen mass ratio of 4:2 holds good physicochemical performance and cytocompatibility.

Tissue engineering composites for bone defect treatment is currently a hot spot of the research field.Mechanical loading on tissue engineering composites is important to bone formation and related research has attracted more and more attention.In the field of tissue engineering research,the establishment of a standardized animal model is the basis of experimental research for exploring the effects of different mechanical loading on in situ repair of bone defect and its action mechanism.This paper reviews the approaches used to establish experimental model of bone defect under mechanical loading such as animal selection,defect preparation,fixation and loading mode in order to provide a reference for related research.

Objective To observe the clinical characteristics in schoolchildren diagnosed with allergic rhi-nitis(AR)and nonallergic rhinitis(NAR)three years ago,and to compare the prevalence of asthma and chronic cough among them and the impacts of AR and NAR on the quality of life. Methods Totally 146 AR children and 108 NAR ones diagnosed between September 2013 and March 2014 were surveyed using a questionnaire by tele-phone and all the children were not complicated with chronic cough and asthma. The statistical analysis was per-formed by a professional statistician using SPSS 12.0 statistical software. Results A total of 111 questionnaires were completed in AR group and 76 in NAR group. The prevalence of asthma was 11.7%(13/111)in AR group while 6.6%(5/76)in NAR group and there was no statistically significant difference(χ2=1.366,P=0.242). The prevalence of chronic cough was 26.1%(29/111)in AR group and 13.2%(10/76)in NAR group and there was sta-tistically significant difference(χ2=4.596,P=0.032). The score of rhinitis visual scale(VAS)and rhinoconjunc-tivitis quality of life questionnaire(RQLQ)was significant higher in AR group than that in NAR group(t = 2.570 and 2.467,P=0.012 and 0.016). Conclusions Children with NAR may also have the risk for the development of asthma as those with AR. The prevalence of chronic cough is higher in children with AR than in those with NAR. AR might bring more impacts on children′s quality of life than NAR.

Objective:To investigate the clinical significance of TMB among CRC patients after R 0 resection and capecitabine-based adjuvant chemotherapy. Methods:Data of 82 CRC patients were reviewed retrospectively. Tumor tissue specimens were collected for DNA extraction . Somatic mutation detection and TMB analysis were performed using next-generation sequencing (NGS) of tumor-related genes. The univariate analysis between TMB status and prognosis was carried out by Kaplan-Meier survival analysis and adjusted by multivariate COX regression analysis subsequently.Results:In these 82 cases,with the median follow-up period was 5.5 years the median disease-free survival (DFS) was 4.5 years, and the median overall survival (OS) was 5.7 years. The most common mutated somatic genes were TP53, APC, KRAS and PIK3CA, with the mutation frequencies of 68.3%, 64.6%, 46.3% and 29.3%, respectively. Other somatic mutant genes were of a relatively low frequency (<25%). The overall somatic mutation burden was relatively low. TMB status was divided into TMB-L (≤3.6/Mb) and TMB-H (>3.6/Mb) according to the median TMB threshold. And the patients with TMB-L and TMB-H were 42 cases and 40 cases, respectively. The median OS in patients with TMB-L and TMB-H was 6.5 and 4.7 years, respectively (χ 2=6.59, P=0.010). TMB status was an independent factor for OS ( HR=0.73, P=0.021). Conclusion:TMB is a biomarker for evaluating the prognosis of CRC patients after surgical resection and receiving capecitabine-based adjuvant chemotherapy .

Objective:To analyze the current status of neonatal nosocomial infection research at home and abroad, explore its research hotspots and development trends, and provide evidence for further research on the prevention and treatment of neonatal nosocomial infection.Methods:The Chinese and English literature related to neonatal nosocomial infection included in CNKI and Web of Science Database from 2010 to 2021 were searched, and CiteSpace 6.1.R2 and VOSviewer1.6.18 software were used to map the authors, institutions, countries, and keywords of the included literature. At the same time, the burst item map was used to predict the future research development trends to a certain extent.Results:A total of 235 authors and 2 core teams of Chinese literature (1 639 articles), 157 authors and 2 core teams of English literature (1 322 articles) were analyzed. 659 Chinese keywords and 1 330 English keywords were extracted, including "nosocomial infection", "risk factors", "infection", "epidemiology", etc. From these literature, 13 Chinese literature clusters and 6 English clusters were generated, and the clustering results were significant and reasonable. The current research hotspots in China focused on pregnancy outcomes and nursing management, while the hotspots of foreign researches focused on sequelae and disease burden.Conclusions:Compared with international research, domestic research on neonatal nosocomial infection hasn't combined with social, environmental and other related factors, while international research teams have begun to shift the focus of research on neonatal nosocomial infections to disease burden and infection sequelae. In the future, cooperation between domestic and foreign research teams should be strengthened, focusing on the frontier trend of international research, and improving the depth and breadth of research.

Objective:To evaluate the effects of supra-arch branches bypass on cerebral oxygen saturation and hemodynamics in patients with Stanford type B aortic dissection.Methods:From January to December 2018, consecutive 27 patients with Stanford type B aortic dissection were enrolled in the study. All patients received hybrid treatment, including supra-arch branches bypass(right axillary artery-left common carotid artery-left subclavian artery) and thoracic endovascular aortic repaire(TEVAR). All the operations were performed by the same surgical team. The left and right cerebral oxygen saturation were measured after anesthesia(T1), left carotid artery occlusion(T2) and after operation(T3); peak systolic velocity(PSV) and resistance index(RI) of left and right carotid arteries were measured before(t1) and after operation(t2).Results:The left cerebral oxygen saturation was 0.62 ±0.01, 0.54±0.01 and 0.62±0.01 at T1, T2 and T3, respectively. There was significant difference between T2 and T1 and T3( P=0.002, P=0.001), but there was no significant difference between T1 and T3. The PSV of left carotid artery at t1 and t2 were(0.91±0.11)m/s and(0.76±0.09)m/s respectively, with no significant difference( P= 0.191). The RI of left carotid artery at t1 and t2 were 0.83±0.06 and 0.93±0.13 respectively, with no significant difference( P= 0.575). Conclusion:If one side of carotid artery was blocked for a short time during supra-arch branches bypass, the cerebral oxygen saturation would be decreased temporarily, but the changes of cerebral oxygen metabolism could be completely restored after operation. However, the hemodynamics of carotid artery would not change significantly. In the hybrid treatment strategy for the patients with aortic dissection Stanford type B, blocking bilateral carotid arteries can be avoided. Making the right axillary artery-left common carotid artery-left subclavian artery shunt is a safe and effective choice.

Objective:To identify the causative genes of sporadic thoracic aortic aneurysm or dissection (TAAD) and their correlation with clinical phenotype in the southern Chinese.Methods:We analyzed 11 core genes of TAAD probands without specific family history of 226 cases by next-generation sequencing technology, and performed sanger sequencing for their close relatives. Clinical data of each patient, including age of onset, syndromic phenotypes, involvement of aortic root, aortic maximum diameter and D-dimer were collected. And statistical software SPSS was used to evaluate the correlation between clinical phenotypes and gene mutations.Results:A total of 106 variants were detected in 226 probands with gene-positive frequency of 44.69%, consist of 16 pathogenic (P) variants, 18 likely pathogenic (LP) variants and 71 variants of uncertain significance (VUS). More than half of the mutations were from the non-syndromic TAAD, in which the FBN1 still was the most common causative gene. Earlier age of onset, an increase of women, larger diameter of aorta, Stanford B dissection and severe aortic regurgitation were likely to occur on carriers of P/LP, while thoracic aortic aneurysm occurs on carriers of VUS. Phenotype of both syndrome and dissection with aneurysm could increase the likelihood of carrying gene mutation, but D-dimer and involvement of aortic root couldn’t.Conclusion:Patients with sporadic aortic diseases in southern China have significant genetic heterogeneity and specific correlation between their clinical phenotype and gene mutation, especially in non-syndromic population. Earlier age of onset in carriers of FBN1 or ACTA2 genes, and larger maximum diameters of aorta in carrier of P/LP.

Objective:To investigate the preoperative ascending aorta diameter in patients with acute type A aortic dissection in the Chinese population, compares and analyze the differences in preoperative blood biomarkers, and evaluate the impact of the preoperative ascending aorta diameter in this part of patients on the short-term prognosis of patients.Methods:A collection of 641 patients with acute type A aortic dissection who were enrolled in the " Acute Aortic Syndrome High-Risk Early Warning and Intervention Study" project from January 2018 to January 2020 were collected. Divide the patients into two groups (group Ⅰ<55 mm, group Ⅱ≥55 mm) according to the preventive intervention value of ascending aorta diameter recommended by the guideline for studying preoperative ascending aorta diameter difference in blood biomarkers and the influence of ascending aorta diameter on the short-term prognosis of patients. All patients had CT scans to assess the diameter of the ascending aorta before operation.Results:In this study, all patients with acute type A aortic dissection had a mean preoperative ascending aorta diameter of (46.9±9.7)mm. The preoperative ascending aorta diameter of all patients was less than 55 mm, accounted for 84.1%. Male patients were more likely to have aortic dissection than females; most patients' age was less than 60 years old. The preoperative blood inflammatory index counts were higher in the ascending aorta diameter ≥55 mm group. However, the long-term prognosis of patients with different ascending aorta diameters before surgery was not apparent in this study. The preoperative survival rate and short-term survival rate of patients with ascending aorta diameter <55 mm were higher than those of other groups, but the difference was not statistically significant.Conclusion:In patients with acute type A aortic dissection, the diameter of the ascending aorta is usually less than 55 mm. Moreover, the blood inflammatory index counts are high in the preoperative ascending aorta diameter ≥55 mm group. Meanwhile, patients with smaller ascending aorta diameter have better survival rate and short-term prognosis.

Objective To investigate the influence of different cell structures on the static and dynamic mechanical performance of porous titanium alloy scaffolds,and to provide a theoretical mechanical basis for the application of scaffolds in the repair of mandibular bone defects.Methods Porous titanium alloy scaffolds with diamond,cubic,and cross-sectional cubic cell structures were manufactured using three-dimensional printing technology.Uniaxial compression tests and ratcheting fatigue with compression load tests were conducted to analyze the static and dynamic mechanical performances of scaffolds with different cell structures.Results The elastic moduli of the diamond cell,cross-sectional cubic cell,and cubic cell scaffolds were 1.17,0.566,and 0.322 GPa,respectively,and the yield strengths were 71.8,65.1,and 31.8 MPa,respectively.After reaching the stable stage,the ratcheting strains of the cross-sectional cubic,diamond,and cubic cell scaffolds were 3.3%,4.0%,and 4.5%,respectively.The ratcheting strain increased with increasing average stress,stress amplitude,and peak holding time,and decreased with increasing loading rate.Conclusions The evaluation results of the static mechanical performance showed that the diamond cell scaffold was the best,followed by the cross-sectional cubic cell scaffold and the cubic cell scaffold.The evaluation results of the dynamic mechanical performance showed that the cross-sectional cubic cell scaffold performed the best,followed by the diamond cell scaffold,whereas the cubic cell scaffold performed the worst.The fatigue performance of the scaffold is affected by the loading conditions.These results provide new insights for scaffold construction for the repair of mandibular bone defects and provide an experimental basis for further clinical applications of this scaffold technology.