Tbx 4 and Tbx 5 gene expression associated with appendage development and its relationship with the absence of the pelvic fin in Pampus argenteus

The Tbx family is first known through the study of their functions in the body and limbs,and its members Tbx4 and Tbx5 genes are important factors in determining the characteristics of the appendages.Pampus argenteus is one of the important economical marine fishes widely distributed in offshore areas.Therefore,it is necessary to study the role of Tbx family genes in the deletion of pelvic fin in P.argenteus.In this study,we cloned Tbx4 and Tbx5 cDNA sequence of P.argenteus(GenBank:MH709128 and MH712458).The Western blot and real time PCR were used to detect the expressions of Tbx4 and Tbx5 in different developmental stages and tissues of P.argenteus.In addition,whole-mount in-situ hybridization was used to study the localization of Tbx4 and Tbx5 genes in different developmental stages of P.argenteus.Results show that the translation of Tbx4 mRNA was inhibited during the critical period of pelvic fin development.Among different tissues,Tbx4 protein levels were the lowest in the abdominal epithelium,and even lower than that in the pectoral fin,suggesting that the protein expression was also inhibited in the abdominal epithelium of adult P.argenteus.Therefore,the results indicated that upstream genes regulation led to the key stage-specific and low expression of Tbx4 during pelvic fin development and in the abdominal epithelium.

Transient AC Overvoltage Suppression Orientated Reactive Power Control of the Wind Turbine in the LCC-HVDC Sending Grid

High-voltage direct current(HVDC) transmission is a crucial way to solve the reverse distribution of clean energy and loads. The line commutated converter-based HVDC(LCCHVDC) has become a vital structure for HVDC due to its high technological maturity and economic advantages. During the DC fault of LCC-HVDC, such as commutation failure, the reactive power regulation of the AC grid always lags the DC control process, causing overvoltage in the AC sending grid, which brings off-grid risk to the wind power generation based on power electronic devices. Nevertheless, considering that wind turbine generators have fast and flexible reactive power control capability, optimizing the reactive power control of wind turbines to participate in the transient overvoltage suppression of the sending grid not only improves the operational safety at the equipment level but also enhances the voltage stability of the system. This paper firstly analyses the impact of wind turbine's reactive power on AC transient overvoltage. Then, it proposes an improved voltage-reactive power control strategy, which contains a reactive power control delay compensation and a power command optimization based on the voltage time series prediction. The delay compensation is used to reduce the contribution of the untimely reactive power of wind turbines on transient overvoltage, and the power command optimization enables wind turbines to have the ability to regulate transient overvoltage, leading to the variation of AC voltage, thus suppressing the transient overvoltage. Finally, the effectiveness and feasibility of the proposed method are verified in a ±800kV/5000MW LCC-HVDC sending grid model based on MATLAB/Simulink.

Review of the Analysis and Suppression for High-frequency Oscillations of the Grid-connected Wind Power Generation System

High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.

Combined hybrid energy storage system and transmission grid model for peak shaving based on time series operation simulation

This study proposes a combined hybrid energy storage system(HESS) and transmission grid(TG) model, and a corresponding time series operation simulation(TSOS) model is established to relieve the peak-shaving pressure of power systems under the integration of renewable energy. First, a linear model for the optimal operation of the HESS is established, which considers the different power-efficiency characteristics of the pumped storage system, electrochemical storage system, and a new type of liquid compressed air energy storage. Second, a TSOS simulation model for peak shaving is built to maximize the power entering the grid from the wind farms and HESS. Based on the proposed model, this study considers the transmission capacity of a TG. By adding the power-flow constraints of the TG, a TSOS-based HESS and TG combination model for peak shaving is established. Finally, the improved IEEE-39 and IEEE-118 bus systems were considered as examples to verify the effectiveness and feasibility of the proposed model.

Forecast of Observing Time Delay of Strongly Lensed Quasars with the Muztagh-Ata 1.93m Telescope

As a completely independent method,the measurement of time delay of strongly lensed quasars(TDSL)are crucial to resolve the Hubble tension.Extensive monitoring is required but so far limited to a small sample of strongly lensed quasars.Together with several partner institutes,Beijing Normal University is constructing a 1.93 m reflector telescope at the Muztagh-Ata site in west China,which has the world class observing conditions with median seeing of 082 and median sky brightness of 21.74 mag arcsec-2 in V-band during the dark time.The telescope will be equipped with both a three-channel imager/photometer which covers 3500–11,000?wavelength band,and a low-medium resolution(λ/δλ=500/2000/7500)spectrograph.In this paper,we investigate the capability of the Muztagh-Ata 1.93 m telescope in measuring time delays of strongly lensed quasars.We generate mock strongly lensed quasar systems and light curves with microlensing effects based on five known strongly lensed quasars,i.e.,RX J1131-1231,HE 0435-1223,PG 1115+080,WFI 2033-4723 and SDSS 1206+4332.In particular,RX J1131-1231 is generated based on the lens modeling results of Suyu et al.Due to the lack of enough information,the other four systems are calculated by a simple analytical approximation.According to simulations,for RX J1131-like systems(wide variation in time delay between images)the TDSL measurement can be achieved with the precision aboutΔt=0.5 day with four seasons campaign length and 1 day cadence.This accuracy is comparable to the up-coming TDCOSMO project.And it would be better when the campaign length keeps longer and with high cadence.As a result,the capability of the Muztagh-Ata 1.93 m telescope allows it to join the network of TDSL observatories.It will enrich the database for strongly lensed quasar observations and make more precise measurements of time delays,especially considering the unique coordinate of the site.

晚期非小细胞肺癌EGFR突变与^(18)F-FDG PET/CT代谢参数的相关性及其对预后评估的影响

目的:探讨晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者^(18)F-FDG PET/CT代谢参数及临床资料与表皮生长因子受体(epidermal growth factor receptor,EGFR)基因突变状态的相关性。同时探究EGFR基因突变状态对PET/CT代谢参数评估晚期NSCLC患者预后的影响。方法:回顾性分析2017年1月至2018年12月在重庆医科大学附属第一医院接受18F-FDG PET/CT检查并有EGFR基因突变检测结果的109例晚期NSCLC患者。根据患者EGFR基因检测结果分为EGFR突变型组(n=48)与EGFR野生型组(n=61),比较两组间PET/CT代谢参数及临床信息的差异并分析其与EGFR突变状态的关系。随访患者的无进展生存(progression free survival,PFS)状态,分析EGFR突变状态对PET/CT代谢参数评估PFS的影响。结果:多因素Logistic分析发现,女性(OR=12.154,P<0.001)、腺癌(OR=4.822,P=0.019)、低最大标准摄取值(maximum standardized uptake value,SUVmax)(≤9.58,OR=4.347,P=0.005)是EGFR突变的独立预测因子。ROC生存曲线分析肿瘤代谢体积(metabolic tumor volume,MTV)(AUC=0.749,P=0.0002),糖酵解总量(total lesion glycolysis,TLG)(AUC=0.747,P=0.0003)对患者的PFS状态具有预测价值。Cox回归分析发现,在EGFR基因突变型组中,MTV>14.85的患者疾病进展风险更高(HR=2.724,P=0.004);EGFR野生型组中,MTV>12.48的患者疾病进展风险更高(HR=3.195,P=0.002)。结论:对于晚期NSCLC患者,EGFR突变与更低的FDG摄取相关,体积代谢参数具有重要的预后预测价值,但对于EGFR基因突变不同状态,可以考虑不同的标准。

Characteristics of neural growth and cryopreservation of the dorsal root ganglion using three-dimensional collagen hydrogel culture versus conventional culture

In vertebrates, most somatosensory pathways begin with the activation of dorsal root ganglion(DRG) neurons. The development of an appropriate DRG culture method is a prerequisite for establishing in vitro peripheral nerve disease models and for screening therapeutic drugs. In this study, we compared the changes in morphology, molecular biology, and transcriptomics of chicken embryo DRG cultured on tissue culture plates(T-DRG) versus three-dimensional collagen hydrogels(C-DRG). Our results showed that after 7 days of culture, the transcriptomics of T-DRG and C-DRG were quite different. The upregulated genes in C-DRG were mainly related to neurogenesis, axon guidance, and synaptic plasticity, whereas the downregulated genes in C-DRG were mainly related to cell proliferation and cell division. In addition, the genes related to cycles/pathways such as the synaptic vesicle cycle, cyclic adenosine monophosphate signaling pathway, and calcium signaling pathway were activated, while those related to cell-cycle pathways were downregulated. Furthermore, neurogenesis-and myelination-related genes were highly expressed in C-DRG, while epithelial–mesenchymal transition-, apoptosis-, and cell division-related genes were suppressed. Morphological results indicated that the numbers of branches, junctions, and end-point voxels per C-DRG were significantly greater than those per T-DRG. Furthermore, cells were scattered in T-DRG and more concentrated in C-DRG, with a higher ratio of 5-ethynyl-2′-deoxyuridine(EdU)-positive cells in T-DRG compared with C-DRG. C-DRG also had higher S100 calcium-binding protein B(S100 B) and lower α-smooth muscle actin(α-SMA) expression than T-DRG, and contained fewer terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)-positive cells after 48 hours of serum starvation. After cryopreservation, C-DRG maintained more intact morphological characteristics, and had higher viability and less TUNEL-positive cells than T-DRG. Furthermore, newly formed nerve bundles were able to grow along the existing Schwann cells in C-DRG. These results suggest that C-DRG may be a promising in vitro culture model, with better nerve growth and anti-apoptotic ability, quiescent Schwann cells, and higher viability. Results from this study provide a reference for the construction, storage, and transportation of tissue-engineered nerves. The study was approved by the Ethics Committee of Aier School of Ophthalmology, Central South University, China(approval No. 2020-IRB16), on March 15, 2020.

Strongly Lensed Transient Sources:A Review

The past decades have witnessed a lot of progress in gravitational lensing with two main targets:stars and galaxies(with active galactic nuclei).The success is partially attributed to the continuous luminescence of these sources making the detection and monitoring relatively easy.With the running of ongoing and upcoming large facilities/surveys in various electromagnetic and gravitational-wave bands,the era of time-domain surveys would guarantee constant detection of strongly lensed explosive transient events,for example,supernovae in all types,gamma ray bursts with afterglows in all bands,fast radio bursts,and even gravitational waves.Lensed transients have many advantages over the traditional targets in studying the Universe,and magnification effect helps to understand the transients themselves at high redshifts.In this review article,on base of the recent achievements in literature,we summarize the methods of searching for different kinds of lensed transient signals,the latest results on detection and their applications in fundamental physics,astrophysics,and cosmology.At the same time,we give supplementary comments as well as prospects of this emerging research direction that may help readers who are interested in entering this field.

Characteristics of Starch synthesis,Yield and Quality Provide Insights into Rice-Tartary Buckwheat Utilization and Improvement

[Objectives] Rice-Tartary buckwheat is a special type of Tartary buckwheat with easy hulling thin shell.This study was conducted to characterize the carbohydrate metabolism,quality and yield and provide a basis for food processing and breeding of rice-Tartary buckwheat.[Methods]The local rice-Tartary buckwheat‘cv.Xiaomiqiao’(XMQ) was used to explore the characteristics of photosynthesis,starch synthesis enzyme activities,traits of yield and quality,as compared to Tartary buckwheat‘cv.Jinqiao 2’(JQ2).[Results]XMQ showed significantly lower values of net photosynthetic rate,ADPGase activity and starch synthase activity at one or more periods during grain filling than JQ2.The effective branch number and grain number per plant of XMQ were similar to that of JQ2 regardless of different years,but the 1 000-grain weight was significantly lighter that resulted in the significantly lower yield.XMQ accumulated similar contents of starch(amylose,amylopectin) and protein(glutelin,albumin,prolamin,globulin) to those of JQ2,but exhibited significantly lower flavonoid content.The values of peak viscosity and hot paste viscosity in XMQ were similar to those of JQ2,but the values of cool paste viscosity,breakdown and setback were significantly lower.In conclusion,XMQ showed low yield due to the insufficient of photosynthesis and starch synthesis.XMQ exhibited high nutritional quality as well as normal Tartary buckwheat and stored 18.88 mg/g of flavonoid,that might be consumed as daily diet.[Conclusions]The present results will provide a basis for utilization and improvement of rice-Tartary buckwheat.

Clinical and microstructural changes with different iontophoresis-assisted corneal cross-linking methods for keratoconus

AIM: To compare the clinical and microstructural changes induced by different transepithelial iontophoresis-assisted corneal cross-linking(I-CXL) methods for keratoconus. METHODS: A total of 42 eyes of 42 patients with progressive keratoconus were divided into two groups. Group A received I-CXL for 5 min, while group B received I-CXL for 10 min. Visual acuity, optical coherence tomography(OCT), specular microscopy and confocal microscopy were evaluated preoperatively and at 1, 3, 6, and 12 mo postoperatively. RESULTS: Twelve months after the operation, uncorrected visual acuity(UCVA) and corrected distance visual acuity(CDVA) were improved in both groups, with a better outcome in the I-CXL 10 min group(P=0.025, 0.021, respectively). Kmax values decreased by 0.94±3.00 D in the I-CXL 10 min group(P=0.033) but increased by 1.87±3.29 D in the I-CXL 5 min group(P=0.012). OCT scans showed that the demarcation line was most visible and substantially deeper in the I-CXL 10 min group. Confocal microscopy showed greater anterior stromal keratocyte decreases in the I-CXL 10 min group than in the I-CXL 5 min group at 3 and 6 mo postoperatively(P<0.001); however, anterior stromal keratocytes and subbasal nerve density were not significantly different between the two groups at 12 mo postoperatively. CONCLUSION: I-CXL for 10 min more effectively halts the progression of keratoconus than I-CXL for 5 min after 12 mo of follow-up. However, long-term studies are needed to evaluate the efficacy and safety of I-CXL.

GC-MS Analysis of Metabolites in Filling Grains of Rice-Tartary Buckwheat (Fagopyrum tataricum) in Comparison to Conventional Tartary Buckwheat

Rice-Tartary buckwheat(RTB)is a special germplasm of Tartary buckwheat.In this study,the appraisal of taste quality between RTB and conventional Tartary buckwheat(CTB)was presented,and the metabolites in kernels at three typical grain filling stage(GFS)were investigated.Unlike CTB,RTB showed thin shell seeds without longitudinal furrows at maturity,which was easily artificially dehulled.Sense organ test indicated that RTB exhibited better taste quality because of the higher values of appearance,viscosity,taste and summary were appraised.In total,92 metabolites were identified in kernels using GM-MS metabolomics platform.The levels of most metabolites changed greatly during grain filling and a large numbers of metabolite-metabolite correlations were found by Pearson correlation coefficient analysis.ANOVA analysis identified 61 differentially expressed metabolites between RTB and CTB,while Venn diagram analysis screened 35 common differential metabolites.Compared with CTB,RTB showed similar levels of lysine and methionine,indicated that RTB own excellent nutritional value.Additionally,RTB exhibited significantly up-regulated levels of most sweeteners(sugars and polyols),which might contribute to better taste.This work provides the first comprehensive metabolomics analysis of kernels between RTB and CTB,which may potentially provide theoretical basis for further research.

Observational constraints on the new generalized Chaplygin gas model

We use the latest data to investigate observational constraints on the new generalized Chaplygin gas （NGCG） model. Using the Markov Chain Monte Carlo method, we constrain the NGCG model with type Ia supernovae from the Union2 set （557 data）, the usual baryonic acoustic oscillation （BAO） observation from the spectroscopic Sloan Digital Sky Survey data release 7 galaxy sample, the cosmic mi- crowave background observation from the 7-year Wilkinson Microwave Anisotropy Probe results, newly revised data on H（z）, as well as a value of θBAO （Z = 0.55） = （3.90° ±0.38°） for the angular BAO scale. The constraint results for the NGCG model are ωX=-1.0510＋0.1563-0.1685（1σ）＋0.2226-0.2398（2σ）,η=1.0117＋0.0469-0.0502（1σ）＋0.0693-0.0716（2σ）and ΩX=0.7297＋0.0229-0.0276（1σ）＋0.0329-0.0402（2σ）, which give a rather stringent constraint. From the results, we can see that a phantom model is slightly favored and the proba- bility that energy transfers from dark matter to dark energy is a little larger than the inverse.

Molecular Cloning and Characteristics Analysis of ghrelin Gene in Asian Swamp Eel(Monopterus albus)

Ghrelin is an important signaling molecule linking reproductive and energy metabolism. In this study, ghrelin gene of Monopterus albus was cloned. Its structure and function were analysized preliminarily. By Rapid Amplification of cDNA Ends(RACE) technique, full-length cDNA and DNA sequences of ghrelin gene were obtained. The full-length ghrelin cDNA(GenBank accession no. JX122807) was 552 bp long, containing a 115 bp 5'-untranslated region, a 324 bp open reading frame and a 113 bp 3'-untranslated region. The full-length ghrelin DNA was 1 323 bp, consisting of three introns and four exons. The exon/intron junction sequences conformed to the GT/AG rule. Three introns were 594, 84 and 93 bp in length, respectively; four exons were229, 78, 112 and 133 bp in length, respectively. The results of amino acid sequence analysis showed that the deduced propreghrelin sequence of M. albus contained a signal peptide(SP) consisting of 22 amino acid residues, a mature peptide(MP)consisting of 19 amino acid residues and a C-terminal amino acid residue. Among them, the third amino acid of MP was serine(Ser^3) as the site for N-acylation and N-deacetylation reactions; the C-terminal amino acid residue sequence might contain a peptide hormone obestatin, which is a physiological antagonist of mature Ghrelin peptide. The homology and phylogenic relationships analyses of amino acid sequences suggested that propreghrelin of M. albus had high similarity to those of several Perciformes fishes; the propreghrelins of M. albus, Perciformes and Heterosomata fishes were clustered into a subgroup. The high conservatism of the gene structure and the amino acid sequences indicated that Ghrelin exerts important physiological functions and plays similar physiological mechanisms in vertebrates.

Small Signal Stability Analysis for a DFIG-Based Offshore Wind Farms Collected Through VSC-HVDC Transmission System

This paper modeled a doubly fed induction generator (DFIG) - based offshore wind farm integrated through a voltage source converter –based high voltage direct current (VSC-HVDC) transmission system, which is collected with infinite bus for small signal stability analysis. The control system of HVDC system is considered for the stability analysis. The impact of the VSC control parameters on the network stability is studied. The lineared dynamic model is employed to do small signal stability analysis by the eigenvalue analysis. The locus of the eigenvalue, which is corresponding to the oscillation model is studied. Time domain simulations conducted in Matlab/Simulink are used to validate the small signal stability analysis.

Small-Signal Stability Analysis of Wind Power System Based on DFIG

This paper focuses on the small-signal stability of power system integrated with DFIG-based wind farm. The model of DFIG for small-signal stability analysis has built;the 3-generator 9-bus WECC test system is modified to investigate the impacts of large scale integration of wind power on power system small-signal stability. Different oscillatory modes are obtained with their eigenvalue, frequency and damping ratio, the results from eigenvalue analysis are presented to demonstrate the small-signal stability of power system is enhanced with the increasing output of the wind farm.

Gene Coding Sequence Identification Using Kernel Fuzzy C-Mean Clustering and Takagi-Sugeno Fuzzy Model

Sequence analysis technology under big data provides unprecedented opportunities for modern life science. A novel gene coding sequence identification method is proposed in this paper. Firstly, an improved short-time Fourier transform algorithm based on Morlet wavelet is applied to extract the power spectrum of DNA sequence. Then, threshold value determination method based on kernel fuzzy C-mean clustering is used to combine Signal to Noise Ratio (SNR) data of exon and intron into a sequence, classify the sequence into two types, calculate the weighted sum of two SNR clustering centers obtained and the discrimination threshold value. Finally, exon interval endpoint identification algorithm based on Takagi-Sugeno fuzzy identification model is presented to train Takagi-Sugeno model, optimize model parameters with Levenberg-Marquardt least square method, complete model and determine fuzzy rule. To verify the effectiveness of the proposed method, example tests are conducted on typical gene sequence sample data.

Discovery and evaluation of a novel ^(18)F-labeled vasopressin 1a receptor PET ligand with peripheral binding specificity

The arginine-vasopressin(AVP)hormone plays a pivotal role in regulating various physiological processes,such as hormone secretion,cardiovascular modulation,and social behavior.Recent studies have highlighted the V1a receptor as a promising therapeutic target.In-depth insights into V1a receptor-related pathologies,attained through in vivo imaging and quantification in both peripheral organs and the central nervous system(CNS),could significantly advance the development of effective V1a inhibitors.To address this need,we develop a novel V1a-targeted positron emission tomography(PET)ligand,[^(18)F]V1A-2303([^(18)F]8),which demonstrates favorable in vitro binding affinity and selectivity for the V1a receptor.Specific tracer binding in peripheral tissues was also confirmed through rigorous cell uptake studies,autoradiography,biodistribution assessments.Furthermore,[^(18)F]8 was employed in PET imaging and arterial blood sampling studies in healthy rhesus monkeys to assess its brain permeability and specificity,whole-body distribution,and kinetic properties.Our research indicated[^(18)F]8 as a valuable tool for noninvasively studying V1a receptors in peripheral organs,and as a foundational element for the development of next-generation,brain-penetrant ligands specifically designed for the CNS.

基于云模型的老旧小区韧性评价体系

为精准、高效改善城市老旧小区居住环境品质,提高其防灾、减灾能力,提出一种基于云模型的老旧小区韧性评价体系。基于韧性理论,对所选老旧小区按照不同年代进行分组,通过实地调研,获得陕西省西安市30组具有代表性的老旧小区特征数据,参考相关文献及相关专家建议,确定建筑韧性、设施韧性、环境韧性、人员韧性共计4个一级指标、9个二级指标、30个三级指标,构成老旧小区的评价指标体系。采用层次分析法(analytic hierarchy process,AHP)确定各指标的主观权重,采用熵权法(entropy weight method,EWN)和准则去除效果法(method based on the removal effects of criteria,MEREC)确定客观权重,采用组合赋权法确定最终权重,运用MATLAB构建了基于云模型的老旧小区韧性评价体系。基于此评价体系,选取西安市一老旧小区——万庆巷小区进行韧性评价,所得结果能够较准确地反映该小区韧性薄弱环节,表明所建评价体系具有一定的适用性与有效性。

像差引导的准分子激光联合角膜胶原交联治疗早期圆锥角膜的临床观察

目的:观察像差引导的经上皮准分子激光屈光性角膜切削术(WG-TransPRK)联合快速角膜胶原交联术(A-CXL)治疗早期圆锥角膜的临床疗效和安全性。方法:回顾性系列病例研究。收集在武汉爱尔眼科医院汉口医院行WG-TransPRK同期联合A-CXL的早期圆锥角膜患者7例(12眼),并于术前,术后1周、1个月、3个月、6个月、1年分别行裸眼视力(UCVA,LogMAR)、最佳矫正视力(BCVA,LogMAR)、屈光度、角膜地形图、共焦显微镜和角膜像差检查。数据采用配对t检验分析。结果:术后1年,UCVA从0.77±0.25改善到0.34±0.26(P=0.001),BCVA从0.18±0.21改善到0.05±0.09(P=0.034);角膜前表面平坦曲率(K1)、角膜前表面陡峭曲率(K2)、角膜前表面最大角膜曲率(Kmax)分别从(43.85±1.72)D、(46.64±2.36)D、(48.88±3.62)D降至(40.63±2.13)D(t=9.48,P=0.001)、(42.27±1.89)D(t=8.29,P=0.001)、(45.43±1.54)D(t=3.02,P=0.014),差异均有统计学意义(均P<0.05)。共聚焦显微镜观察上皮下神经纤维密度降低(P=0.001);浅、中层基质细胞密度降低(均P<0.05),深基质及内皮细胞密度变化差异无统计学意义。4mm直径分析区域角膜总像差与角膜球差降低,差异均有统计学意义(均P<0.05)。结论:WG-TransPRK联合A-CXL能安全有效治疗早期圆锥角膜,提升患者视力。

Preliminary animal studies on observation of injured spinal cord with intraoperative ultrasound backscatter microscopy

Many studies have shown that strategies of nerve regeneration and cell-based transplantation are valid based on animal models of spinal cord injury (SCI).To apply these strategies and bridge spinal cord defects,the identification and precise localization of lesions during spinal cord surgery is necessary.The aim of the present experiment was to evaluate the capabilities of ultrasound backscatter microscopy (UBM) in identifying morphologic changes after SCI.After laminectomy,high-resolution ultrasound images of the spinal cord were obtained in one normal and seven spinal cord-injured adult Wistar rats using a UBM system with a 55-MHz center frequency scanner.Comparison between histoanatomic and UBM images was also performed.The results showed that UBM can identify cysts after the experimental SCI is removed in adult rats.In addition,the glial scar formed in secondary injury showed obvious hyperechoic speckle in the UBM image and correlated with the histoanatomic image.UBM has obvious clinical value in nerve regeneration and cell-based transplantation strategies in injured spinal cords.