ObjectiveThe widespread adoption of portable fundus cameras for primary care and community screening is hindered by limitations in current autofocus(AF) technologies. Image-based methods relying on sharpness evaluation require iterative searches, resulting in slow convergence, while projection-based techniques are susceptible to optical artifacts and calibration errors. To address these challenges, this study introduces a novel AF system based on direct wavefront sensing, designed to deliver simultaneous high speed, high precision, and operational robustness within the compact form factor essential for portable ophthalmic devices. MethodsOur approach fundamentally reimagines the AF process by directly measuring the ocular wavefront aberration. We developed a custom portable fundus camera integrating a miniaturized Shack-Hartmann wavefront sensor (SHWS) into the optical path. An 850 nm laser diode projects a point source onto the retina via oblique illumination to minimize corneal reflections. Light scattered from this spot carries the eye’s refractive error through the imaging optics and is directed to the SHWS, positioned at a plane optically conjugate to the primary color CMOS imaging sensor. A microlens array within the SHWS samples the incident wavefront, generating a pattern of focal spots on a CCD. Real-time centroid analysis of these spots provides a map of local wavefront slopes. These measurements are processed through a singular value decomposition (SVD) algorithm to fit a Zernike polynomial basis set, enabling real-time reconstruction of the wavefront phase. The defocus component (S) is extracted from the second-order Zernike coefficients, providing a direct, quantitative measure of the refractive error in diopters. This value serves as a precise error signal in a closed-loop control system, which commands a voice-coil actuated focusing lens to its null position in a single, deterministic step, eliminating the need for iterative search algorithms. ResultsComprehensive evaluation demonstrated the system’s high performance. Testing on a calibrated model eye (OEMI-7) established a highly linear relationship between the computed defocus S and the focusing lens position across a ±20 Diopter (D) compensation range, achievable within a 5 mm mechanical travel. The system achieved a focusing precision of 0.08 D, corresponding to an 18-fold improvement over a conventional projection spot-size method tested under identical conditions. The total focus acquisition time, encompassing wavefront measurement, computation, and lens actuation, averaged under 0.5 s. Clinical validation with 25 human volunteers (50 eyes, refractive range -15 D to +10 D) confirmed practical efficacy. The wavefront-sensing AF succeeded in 92% of attempts with a mean time of 0.5 s, substantially outperforming a projection-based benchmark which achieved only a 32% success rate with an average time of 4.25 s. The system provided instantaneous directional guidance and maintained stability during minor ocular movements. Objective assessment of image quality, via amplitude contrast of retinal vasculature, showed consistent and significant enhancement following AF correction across the entire tested diopter range. ConclusionThis work successfully implements and validates a direct wavefront-sensing autofocus paradigm for portable fundus cameras. By directly quantifying and compensating for the optical defocus aberration, this method bypasses the fundamental limitations of image-processing and projection-based techniques, enabling rapid, precise, and deterministic diopter compensation. The developed system delivers an exceptional combination of a wide operational range (±20 D), high accuracy (0.08 D), fast convergence (0.5 s), and a compact physical footprint. This technology provides a practical and high-performance focusing solution capable of enhancing the reliability, throughput, and diagnostic utility of portable retinal imaging in large-scale screening applications. Future efforts will be directed towards system cost optimization and performance adaptation for diverse ocular conditions.

Objective To explore the application effect of ultrasound-assisted localization in spinal anesthesia for elderly patients with hip fractures.Methods A total of 114 elderly patients undergoing hip fracture surgery with spinal anesthesia in our hospital from September 2022 to June 2024 were enrolled.The random number table method was applied to allocate participants into two groups:surface anatomical landmark localization group and ultrasound-assisted localization group,with 57 patients in each group.Both groups of patients underwent spinal anesthesia via the paramedian approach for puncture.The first-attempt puncture success rate,success rate of the initial puncture site,number of skin punctures,number of adjusted epidural needle direction,positioning time of the puncture point,puncture time(puncture success time,anesthesia time,and total time),adverse events during the puncture process(nerve hypersensitivity and accidental puncture of the dura mater),spinal anesthesia related complications(back pain,headache,and nerve injury),patient satisfaction and hospital stay were observed and compared between the two groups.The quality of early postoperative recovery was evaluated by using the 15-Item Quality of Recovery(QOR-15)scale at 24 h after surgery.Results The first-attempt puncture success rate in the ultrasound-assisted localization group was 71.9％(41/57),which was significantly higher than that in the surface anatomical landmark localization group[28.1％(16/57),x2=21.930,P=0.000].The success rate of the initial puncture site in the ultrasound-assisted localization group was 87.7％(50/57),which was significantly higher than that in the surface anatomical landmark localization group[54.4％(31/57),x2=15.396,P=0.000].The number of skin punctures and adjusted epidural needle direction in the ultrasound-assisted localization group were 1(1,1)and 0(0,1)times,while in the surface anatomical landmark localization group were 2(1,3)and 3(0,5)times,with statistically significant differences(all P=0.000).The puncture positioning time in the ultrasound-assisted localization group was 2.2(1.7,3.2)min,which was significantly longer than that in the surface anatomical landmark localization group[0.8(0.5,1.2)min,Z=-8.418,P=0.000].The puncture success time,anesthesia time,and total time of the ultrasound-assisted localization group were 1.9(1.7,2.3),4.9(4.3,5.3),and 7.1(6.3,8.7)min,while of the surface anatomical landmark localization group were 5.1(2.3,8.0),7.9(5.7,11.0),and 8.6(6.6,12.0)min,with statistically significant differences(all P＜0.05).There were no statistically significant differences in the incidence of nerve hypersensitivity during operation(3.5％vs.7.0％,x2=0.176,P=0.675),accidental puncture of the dura mater by epidural needles(0％vs.3.5％,P=0.496),postoperative headache(0％vs.3.5％,P=0.496),and back pain(1.8％vs.10.5％,x2=2.435,P=0.119)between the two groups.Both groups of patients showed no symptoms of nerve injury after surgery.There were no statistically significant differences in QOR-15 scores at 24 h postoperatively[119(115,124)points vs.116(112,121)points,Z=-1.858,P=0.063]and length of hospital stay[10.0(9.0,12.5)dvs.10.0(8.0,13.0)d,Z=-0.043,P=0.966]between the two groups.The satisfaction of patients in the ultrasound-assisted localization group was significantly higher than that in the surface anatomical landmark localization group(P=0.004).Conclusion Application of ultrasound-guided localization in spinal anesthesia for elderly patients with hip fractures significantly improves the first-attempt puncture and initial puncture site success rates,reduces skin puncture attempts and adjustments of the epidural needle direction,shortens time of anesthetic procedure,and enhances patient satisfaction,making it highly recommendable for clinical use.

Objective:To compare the efficacy of body posture combined with pharmacotherapy and pharmacotherapy alone in the treatment of chronic subdural hematoma(CSDH).Methods:Firstly, retrospective case series study was conducted. Thirty cases of CSDH that had received body posture combined with pharmacotherapy at Department of Neurosurgery, Huashan Hospital Affiliated to Fudan University from December 2016 to October 2020 were studied retrospectively. Twenty-seven patients were male, and 3 patients were female. The age of patients ( M(IQR)) was 66(16) years (range:28 to 84). Nineteen patients had unilateral hematoma, and 11 patients had bilateral hematoma. All patients received pharmacotherapy and body posture therapy that was to raise their lower limbs 20 to 30 cm with leg lift pad and get abdominal compressed with customized abdominal belt in supine position. Patients were required to maintain the body posture as much as possible, with the maximum to 16 to 18 hours per day. Patients with unilateral hematoma should tilt the head to the affected side and avoid tilting it to the opposite side. For patients with bilateral hematoma, there was no need for head lateralization. Patient were treated with oral dexamethasone and atorvastatin simultaneously. The preliminary efficacy of body posture combined with pharmacotherapy was determined by hematoma improvement rate which was analyzed by Clopper-Pearson method. Then, the multi-center, prospective, randomized controlled trial had carried out in 9 medical centers from August 2020 to November 2021. The stratified block randomization method was adopted. Patients were randomized in a ratio of 1∶1 to either receive pharmacotherapy alone(the control group) or body posture combined with pharmacotherapy(the experiment group) for 3 months and followed up for 6 months. Effective treatment was defined as complete absorption of hematoma, or the hematoma volume decreased by more than 10 ml and Markwalder grading scale score had improved by more than 1 point compared to the baseline. The efficacy rate and surgery conversion rate at 3 months and recurrence at 6 months were observed. Comparison between groups was performed with paired sample t test, Mann-Whitney U test, χ2 test, corrected χ2 test, or Fisher exact probability method. Logistic regression was used to compare the effective rate and operation rate between the two groups. Results:In the respective study, 30 patients completed follow-up 13 to 353 days after treatment. At the last follow-up, the incidence of almost complete absorption or significantly absorption of hematoma (hematoma volume was significantly reduced accompanied by symptom improvement) was 93.3%. The 95% CI for the incidence that analyzed by the Clopper-Pearson method was 77.9% to 99.2%. One hundred and six patients were enrolled in the multicenter study. Fifty-five patients underwent body posture combined with pharmacotherapy. The age was 74(17) years (range:26 to 92). Thirty-nine patients were males and 16 were females. Fifty-one patients underwent pharmacotherapy alone. The age was 69(12) years (range:48 to 84). Thirty-seven patients were males and 14 were females. The length of body posture recorded in diary card was (15.7±2.3) hours(range:7.6 to 19.3 hours). The efficacy rate in the body posture combined with pharmacotherapy group and pharmacotherapy alone group were 83.6% (46/55) and 56.9% (29/51), respectively at 3 months. The result of the logistic regression analysis showed that the efficacy of body posture combined with pharmacotherapy group was better than that of pharmacotherapy alone group ( OR=3.88,95% CI:1.57 to 9.58, P=0.003). Surgery rate in the body posture combined with pharmacotherapy group and pharmacotherapy alone group were 5.5% (3/55) and 21.6% (11/51) respectively. The result of Logistic regression showed that the pharmacotherapy alone group was more likely to be converted to surgery ( OR=0.21,95% CI:0.05 to 0.80, P=0.023). At the 6 months, no recurrence of cases was found in the body posture combined with pharmacotherapy group. However, the recurrence rate of pharmacotherapy alone group was 6.3% (3/48), there was no significant difference between the two groups ( P>0.05). Conclusion:The effect of body posture combined with pharmacotherapy for chronic subdural hematoma is better than that of pharmacotherapy alone.

Objective Based on the general belief that the tongue characteristics of blood stasis constitution is"purple tongue,tortuous sublingual vessels",this study systematically summarized blood stasis tongue characteristics using artificial intelligence image processing combined with expert evaluation.Methods A physical questionnaire survey was conducted on 1275 college students,and 100 cases were randomly selected from the blood stasis constitution group and the mild constitution group.After collecting the tongue images,Unet,OpenCV,YOLOv5 and YOLOv8 algorithms combined with expert evaluation method were used to extract and analyze the tongue features of the two groups.By comparing the differences of tongue image characteristics between the blood stasis constitution group and the mild constitution group,the tongue characteristics of blood stasis constitution were systematically summarized.Results Compared with the mild constitution group,the proportion of light dark tongue and light purple tongue in the blood stasis constitution group was significantly higher(P＜0.05).The I value,L value and a value of the tongue area 1 in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).The S value and a value of area 2 and area 3 were significantly larger(P＜0.05),and the I value,L value,a value and b value of area 5 were significantly smaller(P＜0.01,P＜0.05).Compared with the mild constitution group,the proportion of tooth marks tongue in the blood stasis constitution group was significantly higher(P＜0.01),the proportion of cracked tongue in the blood stasis constitution group was significantly larger(P＜0.05),and the number of tooth marks,crack area,relative height of crack and relative width of crack in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).Compared with the mild constitution group,the I value,L value,a value and b value of tongue coating area 1 in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05),the I value,L value,S value,a value and b value of tongue coating area 2 were significantly larger(P＜0.01,P＜0.05),the I value,S value,a value and b value of tongue coating area 3 were significantly larger(P＜0.01,P＜0.05),the b value of tongue coating area 4 was significantly larger(P＜0.05),the S value,a value and b value of tongue coating area 5 were significantly larger(P＜0.01,P＜0.05).The proportion of thick tongue coating and greasy tongue coating in the blood stasis group was significantly higher than that in the gentleness group(P＜0.05).Compared with the mild constitution group,the proportion of tortuous,thickened and nodular sublingual collaterals in the blood stasis constitution group was significantly larger(P＜0.01,P＜0.05).The a value,I value,S value,b value and relative width of sublingual collaterals in the blood stasis constitution group were significantly larger(P＜0.01,P＜0.05).Conclusion On the basis of the general belief that the characteristics of blood stasis constitution tongue are dark purple tongue and dark purple sublingual collaterals/varicose veins/thickening,blood stasis constitution people also have new tongue characteristics,such as redder tips and edges,more teeth marks and fissures,thicker and greasier coatings,and yellow fur.These findings offer new insights for"to identify the constitution of traditional Chinese medicine and prevent diseases by observing the tongue manifestation".

Objective To explore the association between plasma fibrinogen(FBG)levels and the risk of in-hospital mortality among patients with septic shock.Methods The clinical data of 563 patients diagnosed with septic shock in the Intensive Care Unit(ICU)of Shenzhen Second People's Hospital from August 1,2018,to December 31,2020,were collected.Patient demographic information,basic vital signs,and blood routine and biochemical indices upon admission were gathered.Moreover,the Acute Physiology and Chronic Health Evaluation Ⅱ(APACHEⅡ)scores were calculated.Binary logistic regression analysis was conducted to explore the correlation between plasma fibrinogen levels and in-hospital mortality in patients with septic shock.Additionally,a generalized additive model(GAM)and smoothed curve fitting were employed to investigate the nonlinear relationship between plasma fibrinogen and in-hospital mortality.Receiver operating characteristic(ROC)curves were constructed for FBG and APACHEⅡ scores to predict in-hospital mortality in septic shock patients.The area under the curve(AUC)was computed to compare the predictive efficacies of the two.Furthermore,a segmented linear regression model was utilized for quantification.Results Binary logistic regression analysis demonstrated a significant negative correlation between plasma fibrinogen levels and in-hospital mortality among patients with septic shock(P<0.05).GAM modeling and smoothed curve fitting disclosed a nonlinear association between plasma fibrinogen levels and in-hospital mortality,with an inflection point at 5.54 g/L.The segmented linear regression model indicated that,to the left of the inflection point(FBG≤5.54 g/L),for every 1 g/L decrease in plasma fibrinogen,the risk of death increased by 24.5%(OR=0.755,P=0.003).Conversely,to the right of the inflection point(FBG>5.54 g/L),the relationship was not statistically significant(OR=1.049,P=0.685).The findings of the subgroup analyses indicated that the characteristics of the subgroups did not alter the relationship between blood fibrinogen levels and in-hospital mortality.Conclusion There is a nonlinear relationship between FBG levels and in-hospital mortality in patients with septic shock,which has predictive value for evaluating the risk of in-hospital mortality in this patient cohort.

Purpose To evaluate the effectiveness of deep learning image reconstruction(DLIR)algorithms in reconstructing lumbar vertebrae images from abdominal CT scans,aiming to reduce radiation dose and eliminate the need for repeat lumbar CT examinations.Materials and Methods A retrospective collection was conducted from March to May 2024 in the First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine.Thirty-two patients who underwent both abdominal and lumbar CT scans in a supine head-first position were enrolled.The abdominal CT(DLIR group)utilized a tube voltage of 120 kVp and a current of 200 mA with high-intensity DLIR for lumbar reconstruction.The standard lumbar CT(lumbar group)used the same voltage with a tube current of 260 mA and was reconstructed using 60%weighted adaptive statistical iterative reconstruction.Objective assessments was used to measure the CT values,noise(standard deviation,SD value),signal-to-noise ratio and contrast-to-noise ratio(excluding adipose tissue)at the third lumbar vertebral pedicle level and the L2/L3 intervertebral disc level for muscle,adipose tissue,cancellous bone,intervertebral discs,dura mater and cortical bone.Subjective assessments employed a five-point scale to evaluate image contrast,noise and sharpness.Results The volume CT dose index in lumbar group and DLIR group were 15.25 mGy and 11.74 mGy,respectively.There was no statistical difference in CT values between the structures of both groups(all P>0.05).Compared with the lumbar group,the DLIR group showed significant reductions in SD values across the measured tissues by 31.09%,35.66%,13.48%,27.82%,24.93%and 15.09%(t=5.09-7.21,all P<0.05).The signal-to-noise ratio improved by 36.40%,52.31%,16.56%,34.13%,38.39%and 18.81%,and the contrast-to-noise ratio improved by 51.70%,51.32%,36.24%,34.47%and 53.56%(t=-9.58--4.23,all P<0.001).The DLIR group significantly outperformed the lumbar group in image contrast[4.45(4.00,5.00)points vs.4.75(4.00,5.00)points],image noise[4.06(4.00,4.00)points vs.4.39(4.00,5.00)points],and spatial resolution of fine structures[4.00(4.00,4.00)points vs.4.27(4.00,5.00)points](Z=-3.80,-4.38,-3.55,all P<0.001).Conclusion Using high-intensity DLIR for abdominal examinations can achieve high-quality lumbar CT images with a 25%reduction in radiation dose,enabling simultaneous abdominal and lumbar scanning in a single session.

Objective To explore the effectiveness of the peripheral arterial calcification scoring system(PACSS)based on computed tomography angiography(CTA)in assessing renal function in patients with peripheral arterial disease(PAD).Methods The clinical data,CTA imaging data,and laboratory results from PAD patients who underwent lower limb artery CTA examination were retrospectively collected.The PACSS was utilized to score the calcification in both lower limb arteries.Participants were categorized into three groups based on their estimated glomerular filtration rate(eGFR)(normal group:eGFR≥90 mL/min;mild renal dysfunction group:eGFR 60-89 mL/min,and moderate to severe renal dysfunction group:eGFR＜60 mL/min).The demographic data,clinical symptoms,and comorbidities among the three groups were compared by analysis of variance(ANOVA).The Spearman correlation coefficient was employed to evaluate the relationship between eGFR,cystatin C,and PACSS score.Results The age(P＜0.001)and PACSS score(P＜0.05)of patients with renal dysfunction were significantly higher than those of patients with normal renal function.However,there were no significant differences in gender,prevalence of diabetes,hypertension,or severe limb ischemia.Spearman correlation analysis showed that eGFR was negatively correlated with PACSS score(r=-0.18 in the right lower limb,P=0.037,r=-0.24 in the left lower limb,P=0.006).In contrast,cystatin C was positively correlated with PACSS score(r=0.26 in the right lower limb,P＜0.001,r=0.22 in the left lower limb,P=0.002).Conclusion The PACSS score of lower limb artery in PAD patients is corre-lated with the severity of renal dysfunction.This finding may facilitate early warning and clinical intervention for PAD patients with renal dysfunction.

Objective:To discuss the ameliorative effect of total flavonoids from corn silk(TFCS)on kidney injury in the rats with urate nephropathy,and to clarify the possible mechanism.Methods:Sixty male Wistar rats were randomly divided into control group,model group,positive control group[benzbromarone(BZM)group,5 mg·kg-1·d-1],low dose of TFCS group(20 mg·kg-1·d-1),medium dose of TFCS group(40 mg·kg-1·d-1),and high dose of TFCS group(80 mg·kg-1·d-1),and there were 10 rats in each group.Except for control group,the rats in the other groups were administered potassium oxonate(350 mg·kg-1)and adenine(70 mg·kg-1)by gavage for 4 weeks to establish the hyperuricemic nephropthy models.The rats in different doses of TFCS groups were treated with TFCS for 2 weeks.Speckle blood flow imager was used to detect the renal blood perfusion of the rats in various groups and the kidney coefficients of the rats in various groups were caculated;HE staining and Masson staining were used to observe the pathomorphology and fibrosis degrees of kidney tissue of the rats in various groups and enzyme-linked immunosorbent assay(ELISA)method was used to detect the levels of uric acid(UA),creatinine(Cr),blood urea nitrogen(BUN),interleukin-6(IL-6),and tumor necrosis factor-α(TNF-α)in the serum and levels of β2-microglobulin(β2-MG)and microalbumin(ALB)in the urine of the rats in various groups;Western blotting method was used to detect the expression levels of urate transporter 1(URAT1),glucose transporter 9(GLUT9),and ATP-binding cassette transporter G2(ABCG2)proteins in kidney tissue of the rats in various groups.Results:Compared with control group,the renal blood perfusion volume of the rats in model group was significantly decreased(P<0.01).Compared with model group,the renal blood perfusion volumes of the rats in BZM group and low,medium,and high doses of TFCS groups were significantly increased(P<0.05 or P<0.01).Compared with control group,the kidney weight of the rats in model group was increased,with visible white granular spots on the surface,absence of blood color,and kidney volume was increased.Compared with model group,the kidney volumes of the rats in BZM group and medium and high doses of TFCS groups were decreased,with color tending toward that in control group,and the white granular spots on the surface were significantly reduced.Compared with model group,the kidney coefficients of the rats in BZM group and medium and high doses of TFCS groups were decreased(P<0.01).The HE staining results showed there were no abnormalities in kidney tissue structure in control group,while there were a small amount of brown-yellow urate crystal deposition and interstitial connective tissue hyperplasia in model group;compared with model group,the kidney tissue damage and inflammatory infiltration were alleviated to varying degrees in BZM group and different doses of TFCS groups.The Masson staining results revealed no obvious collagen fiber deposition in control group,whereas significant blue collagen fiber deposition in kidney tissue of the rats was found in model group,and the collagen volume fraction(CVF)was increased compared with control group(P<0.01);compared with model group,the CVFs of the rats in BZM group and different doses of TFCS groups were decreased(P<0.01).The ELISA results showed that compared with control group,the levels of UA,Cr,BUN,IL-6,and TNF-α in serum of the rats in model group were increased(P<0.01);compared with model group,the levels of UA,Cr,BUN,IL-6,and TNF-α in serum of the rats in BZM group and medium and high doses of TFCS groups were decreased(P<0.01).Compared with control group,the levels of β2-MG and ALB in urinary in model group were increased(P<0.01);compared with model group,the levels of β2-MG and ALB in urinary of the rats in different doses of TFCS groups were decreased(P<0.05 or P<0.01).The Western blotting results showed that compared with control group,the expression levels of URAT1 and GLUT9 proteins in kidney tissue of the rats in BZM group and model group were increased(P<0.01),while the expression level of ABCG2 protein was decreased(P<0.01).Compared with model group,the expression levels of URAT1 and GLUT9 proteins in kidney tissue of the rats in different doses of TFCS groups were decreased(P<0.05 or P<0.01),and the expression level of ABCG2 protein was increased(P<0.01).Conclusion:TFCS can significantly alleviate the kidney injury in the rats with urate nephropathy model,and its mechanism may be related to the downregulation of expression of URAT1 and GLUT9 proteins and upregulation of ABCG2 protein expression in kidney tissue.

The stability of ammonium ion selective electrode is an important indicator to ensure accurate monitoring of ammonia nitrogen concentration in drinking water.However,in long-term monitoring process,interfering ions and water molecules in water samples may penetrate into the interior of the ammonium ion selective electrode to form a water layer,which affects the potential response and stability of the electrode.Perfluorooctanoic acid is a low surface energy material,and doping it in polyaniline can reduce surface energy of the composite and improve surface roughness.In this work,five ammonium ion selective electrodes were prepared by doping polyaniline with different concentrations of perfluorooctanoic acid as a solid contact layer,which made the solid contact layer of electrode had hydrophobic properties,thereby improving stability of the ammonium ion selective electrode.The stability of the ion-selective electrode was evaluated by potential drift experiment,and the optimal doping concentration of perfluorooctanoic acid in the sediment solution was determined to be 5 mmol/L.The experiment results showed that the solid contact layer had a water contact angle of 132o under the doping concentration,the potential drift rate was 41.66 μV/h,and potential drift rate in the aqueous layer test was 1.31 mV/h,which were all better than those of the unmodified electrode.The standard deviation of the electrode potential was 1.42 mV,which was obviously superior to that of the unmodified electrode.The characteristics of high stability of the electrode made it suitable for long-term monitoring of ammonia nitrogen content in water samples.

Microalgae can achieve sustainable CO2 fixation and biomass conversion,making them a green path for carbon capture and conversion.Monitoring extracellular carbonic anhydrase(CA)activity in microalgae is crucial for regulating carbon conversion efficiency.In this study,double-stranded DNA was designed as a capture probe to bind H+,which was produced by CA-catalyzed CO2 hydration.This interaction induced conformational changes in the DNA probe,enhancing fluorescence signals and thereby establishing a recognition and signal transduction mechanism for CA catalytic product.This approach enabled a novel method for measuring CA activity.The response of probe to H+was investigated using ultraviolet visible(UV-Vis)spectroscopy,circular dichroism sepctroscopy,and fluorescence spectroscopy.The experimental results indicated that the fluorescence intensity of the probe increased progressively with rising H+concentration.Using this probe,CA activity detection could be completed within 29 min,with a detection range of 0.35-17500 U/mL and a detection limit of 0.15 U/mL.Compared to traditional methods,this approach offered a lower detection limit and was suitable for analyzing and detecting extracellular CA activity in actual algal samples.