Inteins are unique protein insertion sequences capable of self-excision, enabling the covalent ligation of flanking extein peptides via amide bond formation. This process proceeds spontaneously without requiring external enzymes, cofactors, or chemical reagents, granting inteins exceptional biocompatibility and traceless performance in protein engineering applications. Split inteins represent a specialized and versatile subclass whose splicing domains are encoded by two separate gene fragments rather than a single continuous open reading frame. These fragments, known as the N-terminal (IntN) and C-terminal (IntC) split inteins, associate through non-covalent interactions including hydrophobic forces, hydrogen bonds, and van der Waals forces to assemble into an active three-dimensional structure, which then drives efficient extein ligation and enables protein trans-splicing. Protein trans-splicing mediated by split inteins has become a cornerstone for traceless protein ligation owing to its high specificity and irreversibility, fundamentally reshaping strategies for protein modification, assembly, and functional regulation. Compared with traditional chemical ligation methods, split intein systems require no complex chemical derivatization of peptide fragments and can operate efficiently at micromolar concentrations under physiological conditions, thus avoiding structural and functional damage caused by organic reagents. In contrast to enzymatic ligation tools such as sortase, split inteins eliminate the need for additional enzymes or cofactors, simplifying reaction systems, reducing costs, and minimizing non-specific side products. These distinctive advantages render split inteins highly promising for applications in chemical biology, synthetic biology, and biopharmaceutical development. In recent years, deepened mechanistic understanding has established structure-guided rational design as the primary approach to overcoming key limitations of split inteins, including intrinsic aggregation propensity, strict extein sequence dependence, and limited splicing efficiency. Bioinformatic tools have been used to identify aggregation-prone regions in the IntN fragment, and site-directed mutagenesis of hydrophobic residues, relocation of split sites, or removal of misfolding-prone sequences has substantially reduced in vitro aggregation and improved soluble expression and assembly activity. Rational engineering of catalytic residues and adjacent flexible loops has relaxed strict amino acid preferences at extein junctions, enhancing sequence tolerance and reducing the risk of functional impairment in target proteins. Consensus design based on multiple sequence alignments has yielded ultra-fast splicing variants such as Cfa DnaE and Cat-TerL, which exhibit significantly accelerated kinetics and improved tolerance to denaturing conditions. Meanwhile, advances in structural biology have further clarified the conformational dynamics and catalytic mechanisms of splicing, supporting the precise design of high-performance intein modules. On this basis, electrostatic interaction tuning and metagenomic screening have yielded multiple mutually orthogonal split intein pairs, enabling selective multi-fragment protein ligation and providing new routes for the efficient synthesis of large multi-domain functional proteins. With these engineered split inteins offering continuously improved performance and expanded applicability, protein trans-splicing has been widely applied in numerous cutting-edge areas of protein research and biomedicine. In gene delivery, split intein-based systems overcome the packaging limit of adeno-associated viral vectors, enabling the accurate reconstitution of large therapeutic proteins and base editors in target cells, thereby enhancing the efficacy and scope of gene therapy for genetic diseases. In internal protein sequence editing, split inteins mediate precise sequence replacement and modification in flexible regions or loops of target proteins, without the need for complex multi-step ligation and protein refolding involved in traditional protein semisynthesis. In protein-protein interaction studies, intein-mediated splicing covalently captures transient and weak intracellular complexes, enabling sensitive, high-throughput interaction detection and drug screening. In synthetic biology, conditionally controllable splicing systems support the construction of diverse intracellular and cell-surface biological logic gates for the precise regulation of cellular behavior. In mechanistic biochemical research, split inteins enable photocatalytic proximity labeling and site-specific tagging, allowing the preparation of homogeneous protein samples carrying precise post-translational modifications such as ubiquitination and polyglutamylation for chromatin interactome analysis and epigenetic studies. Moreover, covalent trapping strategies using split inteins stabilize transient enzymatic intermediates, providing unprecedented insights into molecular mechanisms such as nucleosome ubiquitination that are difficult to elucidate using conventional methods. This review systematically summarizes key technological advances in split inteins over the past decade, highlighting engineering strategies, mechanistic insights, and the development of orthogonal components. It comprehensively surveys emerging applications at the frontiers of protein research, analyzes current core challenges, and proposes future directions, particularly emphasizing artificial intelligence-driven de novo design and novel splicing pathways to break existing technical bottlenecks. By enabling traceless, efficient, and versatile protein manipulation, split inteins continue to serve as indispensable tools that drive innovation in protein engineering and fundamental life science research.

ObjectiveTo compare the differences in color， odor， coumarin content and microbial community composition of Angelicae Dahuricae Radix（ADR） during different drying processes， and to explore the correlation between changes in microbial community composition and changes in quality indexes of ADR. MethodsThe fresh ADR was processed at three drying temperatures（50， 70， 100 ℃） by drying and steaming cutting， semi-fresh cutting and drying， fresh cutting and drying， and sulfur fumigation methods. The color values of samples were extracted by Adobe Photoshop 2022 software and subjected to principal component analysis（PCA）， electronic nose was used to identify the odor information of medicinal powders and subjected to loadings analysis， PCA， and linear discriminant analysis（LDA）， and high performance liquid chromatography（HPLC） was used to determine the contents of five coumarins（bergapten， oxypeucedanin， imperatorin， phellopterin， isoimperatorin）. The samples for microbial detection were taken from fresh dried samples， 50 ℃（dried and steamed cut， sulfur fumigated） samples， and 100 ℃（dried and steamed cut） samples when the water content was 50% and 14%， respectively. And the changes of microbial community composition during processing were determined by high-throughput sequencing method. The relationship between the changes of microbial community composition and the changes of odor， color and active component content of ADR during drying process was analyzed by Pearson correlation analysis. ResultsThe color quantification results showed that an increase in drying temperature led to the decrease of brightness value（L）， and the increases of red-green value（a） and yellow-blue value（b）， and the change of processing method had no obvious effect on the color of medicinal materials. The results of odor quantification showed that W1S， W2S， W5S， W2W and W1W sensor were sensitive to the odor changes of ADR and could be used to distinguish ADR decoction pieces from different processing methods. The results of HPLC showed that the coumarin content of ADR decreased with the increase of drying temperature and the delay of processing time， the optimal processing method was drying and steaming cutting method， and the optimal temperature was 50 ℃. High-throughput sequencing results showed that the dominant bacteria in ADR during processing were Achromobacter， Agrobacterium， Nocardioides， Mycobacterium and Enterobacter， the dominant fungi were Coprinopsis， Meyerozyma and Apiotrichum. The results of correlation analysis showed that the quality indexes of ADR were positively correlated with Agrobacterium， Mycobacterium in bacteria， Candida in fungi， and negatively correlated with Bacillus in bacteria. ConclusionThere are significant differences in the color， odor， coumarin content and microbial community composition of ADR in different drying processes， and the best drying method is drying and steaming cutting at 50 ℃. The relative abundance changes of 9 bacterial genera and 4 fungal genera are closely related to the quality formation of ADR during the drying process.

Objective:To examine the distribution of pathogens that cause postoperative nosocomial infections in patients with rectal cancer(RC)and to construct a predictive nomogram for nosocomial infection.Methods:The clinical data of 1537 RC patients admitted to Sir Run Run Shaw Hospital between January 2021 and December 2022 were collected.Patients were assigned 1∶1 by propensity score matching(PSM)to the infection group(n=83)and control group(n=83)based on the occurrence of nosocomial infection.The dis-tribution and drug resistance of bacteria in patients with nosocomial infection were analyzed.Risk factors for postoperative nosocomial infection were identified by least absolute shrinkage and selection operator(LASSO)regression,and a predictive nomogram was con-structed using multivariate logistics regression.The predictive performance of the model was evaluated by receiver operating character-istic(ROC)curve,calibration curve,and decision curve analysis(DCA).Results:A total of 93 strains of pathogens were isolated from the 83 infected patients,including 62 strains of Gram-negative bacteria(66.67%;predominantly Escherichia coli and Pseudomonas ae-ruginosa),25 strains of Gram-positive bacteria(26.88%;mainly Enterococcus faecalis),and 6 strains of fungi(6.45%;all Candida albicans).LASSO and multivariate logistics regression showed that smoking(odds ratio[OR]=3.97,95%CI=1.27-12.43),the dwelling time of drainage tube(OR=1.19,95%CI=1.08-1.30),difference in preoperative and postoperative neutrophil counts(OR=1.23,95%CI=1.01-1.49),and difference between preoperative and postoperative C-reactive protein levels(OR=1.05,95%CI=1.03-1.07)were inde-pendent risk factors for postoperative nosocomial infection in RC patients.The area under the ROC curve of the nomogram constructed based on the above factors was 0.933(95%CI=0.896-0.969).The calibration curve showed that the predicted risk was in good agree-ment with the actual observed risk of infection.In addition,DCA demonstrated that the nomogram has good clinical utility and high net clinical benefits in predicting nosocomial infection.Conclusion:The nomogram constructed in this study has a good predictive perfor-mance in postoperative nosocomial infection in RC patients.

Objective: To analyze the nucleic acid load of human parvovirus B19 in major commercially available blood products in China, including human albumin, human intravenous immunoglobulin, human rabies immunoglobulin and various coagulation factor products, aiming to provide evidence for improving blood product manufacturing processes and quality control of source plasma. Methods: A total of 98 batches of coagulation factor products were tested for human parvovirus B19 nucleic acid using real-time fluorescent quantitative PCR, including 42 batches of human prothrombin complex, 35 batches of human coagulation factor Ⅷ, and 21 batches of human fibrinogen. Additionally, 6 batches of human albumin, 6 batches of human intravenous immunoglobulin, and 38 batches of human rabies immunoglobulin were tested for human parvovirus B19 nucleic acid. Results: Human parvovirus B19 nucleic acid were undetectable in human albumin, human intravenous immunoglobulin and human rabies immunoglobulin. Among the 98 batches of coagulation factor products tested for human parvovirus B19 nucleic acid, B19 nucleic acid reactivity rate was 69.0% (29/42) for human prothrombin complex batches, but nucleic acid concentration were all significantly lower than 10 IU/mL. The reactivity rate of B19 nucleic acid in 35 batches of human coagulation factor Ⅷ was 48.6% (17/35), with nucleic acid concentration all below 10 IU/mL. The reactivity rate of B19 nucleic acid in 21 batches of human fibrinogen was 61.9% (13/21), with nucleic acid concentration all below 10 IU/mL. Conclusion: No human parvovirus B19 has been detected in human albumin, human intravenous immunoglobulin, or human rabies immunoglobulin. Human parvovirus B19 nucleic acid may exist in commercially available coagulation factor products, highlighting the need for enhanced screening of human parvovirus B19 nucleic acid in these products. It is also recommended that B19 viral nucleic acid testing be conducted on source plasma, particularly for coagulation factor products.

Objective: To analyze the nucleic acid load of human parvovirus B19 in major commercially available blood products in China, including human albumin, human intravenous immunoglobulin, human rabies immunoglobulin and various coagulation factor products, aiming to provide evidence for improving blood product manufacturing processes and quality control of source plasma. Methods: A total of 98 batches of coagulation factor products were tested for human parvovirus B19 nucleic acid using real-time fluorescent quantitative PCR, including 42 batches of human prothrombin complex, 35 batches of human coagulation factor Ⅷ, and 21 batches of human fibrinogen. Additionally, 6 batches of human albumin, 6 batches of human intravenous immunoglobulin, and 38 batches of human rabies immunoglobulin were tested for human parvovirus B19 nucleic acid. Results: Human parvovirus B19 nucleic acid were undetectable in human albumin, human intravenous immunoglobulin and human rabies immunoglobulin. Among the 98 batches of coagulation factor products tested for human parvovirus B19 nucleic acid, B19 nucleic acid reactivity rate was 69.0% (29/42) for human prothrombin complex batches, but nucleic acid concentration were all significantly lower than 10 IU/mL. The reactivity rate of B19 nucleic acid in 35 batches of human coagulation factor Ⅷ was 48.6% (17/35), with nucleic acid concentration all below 10 IU/mL. The reactivity rate of B19 nucleic acid in 21 batches of human fibrinogen was 61.9% (13/21), with nucleic acid concentration all below 10 IU/mL. Conclusion: No human parvovirus B19 has been detected in human albumin, human intravenous immunoglobulin, or human rabies immunoglobulin. Human parvovirus B19 nucleic acid may exist in commercially available coagulation factor products, highlighting the need for enhanced screening of human parvovirus B19 nucleic acid in these products. It is also recommended that B19 viral nucleic acid testing be conducted on source plasma, particularly for coagulation factor products.

As a mercury-containing elixir， Hongshengdan has been known as a sacred medicine for surgery by ancient medical practitioners because of its precise curative effects. It originated from Yizong Shuoyue in the Qing dynasty， Qing dynasty and modern medical practitioners have adapted and modified its formula for clinical application. Employing bibliometric methods， the authors systematically organized relevant ancient literature of the Qing dynasty and modern literature， and analyzed the composition and dosage， preparation method， and clinical application. Among the 25 ancient books concerning Hongshengdan， a total of 12 medicinal formulas， 15 refining methods and 9 clinical applications were obtained. Research confirms that Hongshengdan consisted of mercury， saltpeter， alum， soap alum， cinnabar and realgar. Using measurement conversion standards of Qing dynasty， the modern single-batch formulation comprised 37.30 g of mercury， 149.20 g of saltpeter， 37.30 g of alum， 22.38 g of soap alum， 18.65 g of cinnabar， and 18.65 g of realgar. In modern refining of Hongshengdan， most medical practitioners take the core medicines， with dosages approximately 30 g of mercury， 30 g of saltpeter， and 30 g of alum. Refining method involves pretreatment stewing the materials during preparation， and alum， soap alum， and saltpeter are first ground together， then combined with mercury， cinnabar， and realgar for grinding until mercury and other drugs grind to the degree of no star points. The mixture is then placed in a pot or vessel by cold-forming method. After covering， the opening is sealed using either raw gypsum salt mud or honey-dipped cotton paper strips. Sand is packed around the vessel and then pressurized. During the calcination process， begin with a low flame（30 min）， then increase to a medium flame（30 min）， followed by a high flame（30 min）， after removing fire toxins， collect the final product. Hongshengdan has the efficacy of lifting the poison， removing the corrosion， producing muscle and dispersing， and is often used in the treatment of surgical sore and carbuncle type of diseases. Modern research indicates that Hongshengdan is commonly used to treat skin system diseases such as ulcers and herpes. The aforementioned findings provide a reference basis for the subsequent refining method and clinical application of Hongshengdan.

[Objective]To summarize the academic experience of Professor FAN Yongsheng,one of the first national famous traditional Chinese medicine masters,in treating the damp-heat syndrome of rheumatism.[Methods]Through the follow-up study,collecting and organizing Professor FAN Yongsheng's clinical cases of damp-heat syndrome of rheumatism,combined with the relevant ancient books and literature,summarizing the academic experience of Professor FAN Yongsheng in the diagnosis and treatment of damp-heat syndrome of rheumatism by Sanjiao method,focusing on the theoretical origin of Sanjiao method,the division of upper,middle and lower Jiao,as well as the practice of the clinical evidence,and added with the evidence of the experimental cases for support.[Results]The term Sanjiao originated in Huangdi Neijing.ZHANG Zhongjing deepened the concept of the Qi transformation of Sanjiao.XUE Xue pioneered the syndrome differentiation of the Sanjiao framework in Treatise on Dampness and Heat.WU Jutong systematically established the Sanjiao syndrome differentiation system in Systematic Differentiation of Warm Diseases.Professor FAN Yongsheng believes that the etiology of rheumatism with damp-heat syndrome is mostly attributed to insufficient endowment,exogenous or endogenous damp-heat obstruction in the Sanjiao,which results in the evil of damp-heat disturbing the upper-Jiao,trapping in the middle-Jiao and injecting into the lower-Jiao.When treating the disease,the parts of the Sanjiao where the damp-heat is located should be recognized.The treatment according to Sanjiao should be applied respectively with"propagation and opening""clearing"and"osmosis",and at the same time,the overall situation should be taken into account,and the three methods are often used together to eliminate the damp-heat and facilitate the Sanjiao.Three clinical cases demonstrated significant efficacy:Case 1 involved damp-heat clouding the upper-Jiao,treated with heat-clearing,damp-resolving,lung-ventilating and cough-relieving methods;Case 2 featured with damp-heat lodging in the middle-Jiao,managed with heat-clearing,spleen-strengthening and liver-soothing therapies;Case 3 presented damp-heat diffusing to the lower-Jiao,addressed through heat-clearing,damp-draining and collateral-unblocking strategies.All cases achieved satisfactory clinical results.[Conclusion]Professor FAN Yongsheng's academic experience in treating damp-heat syndrome of rheumatism by flexibly utilizing the Sanjiao method,which is based on inheritance,provides a theoretical basis and practical paradigm for the clinical management of rheumatism with damp-heat syndrome and is worth promoting and applying in the clinic.

Objective To construct an evidence-based practice program of discharge preparation services for hip replacement patients based on the best evidence,and to evaluate its clinical effects,aiming to provide references for the implementation of relevant interventions.Methods Knowledge to Action Framework was used as a guide to summarise the best evidence on discharge preparation services for hip replacement patients and to select services based on clinical context.We selected 38 hip replacement patients and 17 healthcare professionals from the De-partment of Orthopaedic Surgery at a tertiary A hospital in Shanghai in September-October 2023 to conduct a baseline review,identify facilitating and hindering factors,and develop a practice protocol.We also selected 38 hip replacement patients and 17 healthcare professionals from November-December 2023 on this ward for evidence-based practice.Nurses'rates of completion of review indicators,levels of knowledge of discharge preparation ser-vices,and discharge planning competencies were compared before and after practice.Patients'readiness for dis-charge,hip function,and unplanned readmissions were also compared before and after the practice.Results After evidence-based practice,nurses'completion rates of review indicators,knowledge of discharge preparation services,and discharge planning competencies were higher than baseline levels(P＜0.05).Hip replacement patients showed a significant improvement in readiness for discharge and hip function(P＜0.001).Conclusion The implementation of an evidence-based practice program of discharge preparation services improves nurses'knowledge and skills,and also contributes to the discharge readiness and hip function of hip replacement patients.

OBJECTIVE: To study effective methods for reducing lung V₅, V₁₀, and mean lung dose (MLD) in the design of volumetric modulated arc therapy for central lung cancer by using different arc configurations and dose-limiting blocks designs. METHODS: Five groups of plans were designed for the enrolled patients. Group A used a full-arc field. Group B used a partial-arc field. Groups C, D, and E used full-arc fields with vertical-length, semi-ring, and triangular dose-limiting blocks added respectively. The dosimetric similarities of target areas and the dosimetric differences in lung V₅, V₁₀, V₂₀, and MLD among the groups were compared. RESULTS: Compared with group A, groups B, C, D, and E had decreased homogeneity and conformity of the target area, but significantly lower V₅ and V₁₀ of the whole lung. The MLD of groups C, D, and E was lower than that of group A. CONCLUSION Using a full-arc field combined with dose-limiting blocks can effectively reduce lung V₅, V₁₀, MLD, and monitor units (MU).
Lung Neoplasms/radiotherapy* ; Humans ; Radiotherapy, Intensity-Modulated/methods* ; Radiotherapy Planning, Computer-Assisted/methods* ; Radiotherapy Dosage ; Lung/radiation effects*

OBJECTIVE To investigate the improvement mechanism of Huatan tongmai decoction on rats with polycystic ovary syndrome （PCOS） by regulating autophagy through phosphatidylinositol-3-kinase（PI3K）/protein kinase B（AKT）/mammalian target of rapamycin （mTOR） pathway. METHODS A total of 40 rats were randomly divided into blank group （purified water）， model group （purified water）， traditional Chinese medicine group [Huatan tongmai decoction， 24 g/（kg·d）] and chemical drug group [metformin， 0.16 g/（kg·d）]， with 10 rats in each group. Except for blank group， other groups were given a combination of high-fat diet and intragastric administration of 1 mg/kg letrozole suspension to establish PCOS rat model. After modeling， they were given relevant medicine or water intragastrically， once a day， for 42 consecutive days. After the last administration， the pathological and ultrastructural changes of ovarian tissue were observed. The levels of follicle stimulating hormone （FSH）， testosterone （T）， estradiol （E2） ，luteinizing hormone （LH） in serum were detected，and the LH/FSH ratio was calculated. mRNA expressions of Beclin-1， p62 and microtubule-associated protein 1 light chain 3 （LC3） in ovarian tissue were detected. The expressions of related proteins of PI3K/AKT/mTOR pathway and autophagy in rat ovarian tissues were also detected. RESULTS Compared with blank group， the pathological damage and ultrastructural changes of the ovarian tissue in the model group rats were obvious， and a large number of autophagosomes could be seen in cells. The levels of T and LH and the LH/FSH ratio in serum， as well as mRNA and protein expressions of Beclin-1 and LC3， were increased significantly （P＜0.05）， while the levels of E2 and FSH in serum， as well as mRNA and protein expressions of p62 and the phosphorylation levels of PI3K， AKT and mTOR proteins in ovarian tissue， were significantly decreased （P＜0.05）. Compared with model group， the pathological damage of ovarian tissue in the administration groups was significantly reduced， the number of autophagosomes was smaller， and the expression levels of the above indicators were significantly reversed （P＜0.05）. CONCLUSIONS Huatan tongmai decoction can inhibit autophagy in ovarian granular cells by activating the PI3K/AKT/mTOR pathway， regulate the secretion of sex hormones， alleviate pathological damage in ovarian tissues， and promote normal follicular development， thereby exerting an ameliorative effect on PCOS rats.