Immobilized enzyme-based enzyme electrode biosensors, characterized by high sensitivity and efficiency, strong specificity, and compact size, demonstrate broad application prospects in life science research, disease diagnosis and monitoring, etc. Immobilization of enzyme is a critical step in determining the performance (stability, sensitivity, and reproducibility) of the biosensors. Random immobilization (physical adsorption, covalent cross-linking, etc.) can easily bring about problems, such as decreased enzyme activity and relatively unstable immobilization. Whereas, directional immobilization utilizing amino acid residue mutation, affinity peptide fusion, or nucleotide-specific binding to restrict the orientation of the enzymes provides new possibilities to solve the problems caused by random immobilization. In this paper, the principles, advantages and disadvantages and the application progress of enzyme electrode biosensors of different directional immobilization strategies for enzyme molecular sensing elements by specific amino acids (lysine, histidine, cysteine, unnatural amino acid) with functional groups introduced based on site-specific mutation, affinity peptides (gold binding peptides, carbon binding peptides, carbohydrate binding domains) fused through genetic engineering, and specific binding between nucleotides and target enzymes (proteins) were reviewed, and the application fields, advantages and limitations of various immobilized enzyme interface characterization techniques were discussed, hoping to provide theoretical and technical guidance for the creation of high-performance enzyme sensing elements and the manufacture of enzyme electrode sensors.

Abstract The harm of head injury in skateboarding is more serious. The common injury cause is fall, collision, high speed impact. The primary types of injury include skull fracture, subdural hemorrhage, brain laceration contusion and concussion. Older children and adolescents, males, longboard, inappropriate sports venue are important risk factors for severe traumatic brain injury. Designing special skateboard parks and wearing protective equipment (helmets) can effectively reduce the incidence and severity of head injuries. The occurrence of injury can be reduced by adopting both legislation and education measures.

Fluorescence anisotropy(FA)analysis has many advantages such as no requirement of separation,high throughput and real-time detection,and thus has been widely used in many fields,including biochemical analysis,food safety detection,environmental monitoring,etc.However,due to the small volume or mass of the target,its combination with the fluorescence probe cannot produce significant signal change.To solve this issue,researchers often use nanomaterials to enhance the mass or volume of fluorophore to improve the sensitivity.Nevertheless,this FA amplification strategy also has some disadvantages.Firstly,nanomaterials are easy to quench fluorescence.As a result,the FA value is easily influenced by light scattering,which reduces the detection accuracy.Secondly,fluorescent probes in most methods require complex modification steps.Therefore,it is necessary to develop new FA probes that do not require the amplification of volume and mass or modification.As a new kind of nanomaterials,luminescent metal-organic framework(MOF)has a large volume(or mass)and strong fluorescence emission.It does not require additional signal amplification materials.As a consequence,it can be used as a potential FA probe.This study successfully synthesized a lanthanide metal organic framework(Ce-TCPP MOF)using cerium ion(Ce3+)as the central ion and 5,10,15,20-tetra(4-carboxylphenyl)porphyrin(H2TCPP)as the ligand through microwave assisted method,and used it as a novel unmodified FA probe to detect phosphate ions(Pi).In the absence of Pi,Ce-TCPP MOF had a significant FA value(r).After addition of Pi,Pi reacted with Ce3+in MOF and destroyed the structure of MOF into the small pieces,resulting in a decrease in r.The experimental results indicated that with the increase of Pi concentration,the change of the r of Ce-TCPP MOF(Δr)gradually increased.The Δr and Pi concentration showed a good linear relationship within the range of 0.5-3.5 μmol/L(0.016-0.108 mg/L).The limit of detection(LOD,3σ/k)was 0.41 μmol/L.The concentration of Pi in the Jialing River water detected by this method was about 0.078 mg/L,and the Pi value detected by ammonium molybdate spectrophotometry was about 0.080 mg/L.The two detection results were consistent with each other,and the detection results also meet the ClassⅡwater quality standard,proving that this method could be used for the detection of Pi in complex water bodies.

AIM: To observe the imaging characteristics of the affected eyes of patients with central serous chorioretinopathy(CSC)of different ages and their asymptomatic fellow eyes.METHODS: Retrospective study. A total of 76 cases(88 eyes)of CSC patients diagnosed in the ophthalmology department of our hospital from April to September, 2023 and 35 cases(35 eyes of asymptomatic fellow eyes of patients with unilateral CSC)were selected for the study. According to age, they were divided into young and middle-aged groups(<40 years old), middle-aged groups(40-50 years old)and middle-aged and elderly groups(>50 years old). The imaging features of the affected eyes of CSC patients of different ages and their asymptomatic fellow eyes were observed.RESULTS: The subfoveal choroidal thickness(SFCT)of CSC eyes in the young and middle-aged patients(487.30±83.33 μm)was significantly greater than that of the middle-aged group(414.17±96.02 μm, P<0.05)and the middle-aged and elderly group(409.4±107.42 μm, P<0.05). The incidence of choroidal neovascularization(CNV)in CSC patients of the middle-aged and elderly group was significantly higher than that in the young and middle-aged group(P<0.0167). The SFCT of the asymptomatic fellow eye of the unilateral CSC patient in the young and middle-aged group(511.29±40.89 μm)was significantly larger than that of the middle-aged and elderly group(364.76±82.26 μm, P<0.05). Among them, the vortex vein anastomosis rate in eyes with CSC is higher than 90%, and vortex vein anastomosis or dilatation is present in all asymptomatic fellow eyes of CSC patients.CONCLUSION: There are differences in the imaging manifestations of CSC-affected eyes and their asymptomatic fellow eyes of different age groups. SFCT is generally thickened and gradually becomes thinner with the growth of age. The incidence of CNV in CSC-affected eyes is the highest in the middle-aged and elderly group. In addition, vortex vein anastomosis and dilatation are common in CSC-affected eyes and asymptomatic fellow eyes.

Objective Pancreatic cancer(PC)is a malignant tumor of the digestive tract that is difficult to diagnose early,easily metastasizes and relapses,and resistant to conventional chemotherapy.PC is a very difficult disease to treat.The key regulatory factors of PC resistance,such as epithelial-mesenchymal transition phenotypic cells,tumor stem cells,and miRNAs,have been reviewed in the past few years,and some new regulatory factors have been discovered as supplements.This review mainly focuses on the characteristics and properties of the key regulatory factors of PC chemotherapy resistance including long noncoding RNAs,nuclear factor KB and exosomes,drug resistance mechanisms,and treatment related strategies,and future treatment directions were predicted.

Objective To investigate the protective effect of dexmedetomidine(Dex)pretreatment on myocardial ischemia-reperfusion mice and the effect of Nod-like receptor protein 3(NLRP3)inflammatory signaling pathway.Methods C57BL/6J mice were randomly divided into sham group(only threading without ligation),model group(recovery after ligation of left anterior descending coronary artery),positive group(modeling after intraperitoneal injection of 1 mg·kg-1 trimetazidine),Dex group(modeling after intraperitoneal injection of 20 μg·kg-1 dexmedetomidine),MCC950 group(modeling after intraperitoneal injection of 10 mg·kg-1 NLRP3 inhibitor MCC950),12 mice in each group.Cardiac function indexes were detected at 24 h after reperfusion,the expression level of related proteins in myocardial tissue was detected by Western blot,enzyme-linked immunosorbent assay(ELISA)was used to detect the expression level of serum factor,myocardial antioxidant index was detected by kit method,and apoptosis was detected by Tunel method.Results The NLRP3 protein expression levels of sham group,model group,positive group,Dex group and MCC950 group were 0.31±0.05,1.06±0.07,0.52±0.05,0.65±0.07 and 0.39±0.04,respectively;the expression levels of apoptosis-associated granuloid protein(ASC)were 0.27±0.08,0.88±0.09,0.46±0.05,0.59±0.07 and 0.34±0.04,respectively;CK-MB levels were(25.64±2.94),(102.08±7.04),(49.61±7.70),(60.86±5.24)and(63.24±5.38)U·L-1,respectively;IL-6 levels were(104.78±10.73),(231.54±15.56),(158.20±16.54),(165.10±14.77)and(141.17±14.08)pg·mL-1,respectively;Tunel positive cell rates were(4.34±0.16)％,(25.98±1.58)％,(8.74±0.93)％,(11.06±1.07)％and(9.19±0.88)％,respectively.Sham group were compared with model group;Dex group and MCC950 group were compared with model group,the above indexes were statistically significant(all P＜0.05).Conclusion Dexmedetomidine preconditioning may prevent ischemia-reperfusion myocardial injury by inhibiting NLRP3/ASC/caspase-1 inflammatory pathway,inflammatory response and myocardial cell apoptosis.

Objective Studies on the relationship between iodine,vitamin A(VA),and vitamin D(VD)and thyroid function are limited.This study aimed to analyze iodine and thyroid-stimulating hormone(TSH)status and their possible relationships with VA,VD,and other factors in postpartum women. Methods A total of 1,311 mothers(896 lactating and 415 non-lactating)from Hebei,Zhejiang,and Guangxi provinces were included in this study.The urinary iodine concentration(UIC),TSH,VA,and VD were measured. Results The median UIC of total and lactating participants were 142.00 μg/L and 139.95 μg/L,respectively.The median TSH,VA,and VD levels in all the participants were 1.89 mIU/L,0.44 μg/mL,and 24.04 ng/mL,respectively.No differences in the UIC were found between lactating and non-lactating mothers.UIC and TSH levels were significantly different among the three provinces.The rural UIC was higher than the urban UIC.Obese mothers had a higher UIC and a higher prevalence of excessive TSH.Higher UICs and TSHs levels were observed in both the VD deficiency and insufficiency groups than in the VD-sufficient group.After adjustment,no linear correlation was observed between UIC and VA/VD.No interaction was found between vitamins A/D and UIC on TSH levels. Conclusion The mothers in the present study had no iodine deficiency.Region,area type,BMI,and VD may be related to the iodine status or TSH levels.

The incidence of intrahepatic cholangiocarcinoma (ICC) continues to rise, and there are no effective drugs to treat it. The immune microenvironment plays an important role in the development of ICC and is currently a research hotspot. Icaritin (ICA) is an innovative traditional Chinese medicine for the treatment of advanced hepatocellular carcinoma. It is considered to have potential immunoregulatory and anti-tumor effects, which is potentially consistent with the understanding of "Fuzheng" in the treatment of tumor in traditional Chinese medicine. However, whether ICA can be used to treat ICC has not been reported. Therefore, in this study, sgp19/kRas, an in situ ICC mouse model with intact immune system, was selected to evaluate the efficacy of ICA in the treatment of ICC in vivo for the first time, and the effects of ICA on the tumor immune microenvironment of ICC mice were analyzed by flow cytometry. This experiment was approved by the Experimental Animal Ethics Committee of Capital Medical University (approval number: AEEI-2023-138). In this study, sgp19/kRas ICC mouse model was treated with oral gavage of 100 mg·kg^-1 ICA. We found that ICA significantly inhibited tumor growth and tumor cell proliferation in the sgp19/kRas ICC mouse model after 3 weeks of treatment. Flow cytometry analysis indicated that ICA treatment markedly reduced the proportion of M2 macrophages and increased the number of CD3⁺CD4⁺ T cells. In vitro experiments demonstrated that ICA promoted macrophage polarization towards the M1 phenotype while inhibiting polarization towards the M2 phenotype. Furthermore, transcriptomic analysis suggested that ICA enhanced Toll-like receptor 9 (TLR9) expression, influencing macrophage nitric oxide metabolism synthesis pathways and receptor-related activities, thereby regulating macrophage polarization. In summary, this study demonstrates that ICA treatment significantly delays tumor progression in sgp19/kRas ICC mouse models. Mechanistically, ICA may achieve its anti-ICC effects by upregulating TLR9 receptor expression levels, promoting macrophage polarization towards the M1 phenotype, and altering the tumor immune microenvironment.

Secondary organic aerosol(SOA)produced by photooxidation of styrene and other aromatic compounds is a major part of fine particles in urban atmosphere.In this study,the measurement of component and content of SOA formed from photooxidation of styrene in smog chamber using synchronous radiation vacuum-ultraviolet photoionization aerosol mass spectrometer(VUV-PIAMS)was conducted.Photoionization mass spectra of styrene SOA was detected by synchrotron radiation photon with 10.5 eV,and the proportion of main components was quantified based on the peak area of each ion peak.The photoionization efficiency curve of ion peak was obtained under synchrotron radiation photons in the range from 7.5 to 11.5 eV,and then the ionization potential was acquired for qualitative analysis of the component structure.The results showed that the photoionization mass spectra of styrene SOA mainly contained ion peaks at m/z 106,108,120 and 122,and the ionization potentials of each peak were(9.41±0.03)eV,(8.93±0.03)eV,(9.24±0.03)eV and(9.25±0.03)eV,respectively.Combined with quantum chemistry calculation and off-line measurement verification of infrared absorption spectra and electrospray ionization mass spectra,it was determined that benzaldehyde,benzyl alcohol,4-vinylphenol and benzoic acid were main components of styrene SOA,accounting for 32.5%,17.5%,25%and 15%of the measured components,respectively,and the generated quantity ratio was 13∶7∶10∶6.VUV-PIAMS could overcome the disadvantages of off-line method,and could on-line detect component and content of SOA,proving a useful tool to measure the chemical components and reveal the formation process of SOA particles.

Objective To explore the risk factors related to afterload mismatch(AM)after transcatheter mitral valve repair(MitraClip).Methods This was a retrospective cohort study.48 patients hospitalized in the Department of Cardiovascular Medicine,the First Affiliated Hospital of Sun Yat-sen University from December 2021 to December 2023,who underwent MitraClip due to severe mitral regurgitation(MR)were included.Preoperative clinical data,laboratory tests,and preoperative and postoperative color Doppler echocardiographic examination results of surgical patients were collected.AM was defined as the left ventricular ejection fraction(LVEF)decreased by 15％or more after surgery compared with the one before(dLVEF≤-15％).Patients were divided into AM group and non-AM group according to whether afterload mismatch occurred.Univariate and multivariate logistic regression were used to analyze the risk factors of postoperative AM.Results Among 48 patients who underwent MitraClip,14 of them(29.2％)developed afterload-mismatched.For those without AM,their overall LVEF was improved after the operation;for patients in both AM group and non-AM group,their overall left ventricular end-diastolic diameter(LVEDd),left ventricular end-diastolic diameter volume index(LVEDVi)was reduced compared with the preoperative ones.Univariate regression analysis showed that C-reactive protein levels(OR 1.98,95％CI 1.02-3.83),platelets(OR 2.22,95％CI 1.08-4.53),systemic immune inflammation index(OR 1.96,95％CI 1.03-3.71)were associated with an increased risk of AM in patients undergoing MitraClip(all P＜0.05),while those with larger right atrial diameter(OR 0.35,95％CI 0.13-0.93)or moderate to severe tricuspid regurgitation(OR 0.19,95％CI 0.05-0.81)were less likely to develop into AM(both P＜0.05),which is still satisfied after adjustment.Conclusions For patients who underwent MitraClip,C-reactive protein levels,platelets and systemic immune inflammation index(SII)are associated with an increased risk of afterload mismatched,while those with larger right atrial diameter or moderate to severe tricuspid regurgitation were less likely to develop into AM.