Design of weak current measurement system and research on temperature impact

A dedicated weak current measurement system was designed to measure the weak currents generated by the neutron ionization chamber.This system incorporates a second-order low-pass filter circuit and the Kalman filtering algorithm to effectively filter out noise and minimize interference in the measurement results.Testing conducted under normal temperature conditions has demonstrated the system's high precision performance.However,it was observed that temperature variations can affect the measurement performance.Data were collected across temperatures ranging from -20 to 70℃,and a temperature correction model was established through linear regression fitting to address this issue.The feasibility of the temperature correction model was confirmed at temperatures of -5 and 40℃,where relative errors remained below 0.1% after applying the temperature correction.The research indicates that the designed measurement system exhibits excellent temperature adaptability and high precision,making it particularly suitable for measuring weak currents.

白内障术前角膜散光检查的新进展

随着人们生活水平的不断提高和生活方式的多样化发展,获得更好的视觉质量已成为现阶段手术治疗白内障的新目标。角膜散光直接影响白内障手术功能性人工晶状体(IOL)种类的选择和患者术后视功能的恢复,角膜散光检查的种类不再局限于单一的散光数值,而是细分成角膜前表面散光、后表面散光、全角膜散光以及高阶角膜散光等,相应的检查设备及技术也有较多更新。临床医生可根据不同设备特点及应用范围,选择适合的检查设备评估术前角膜散光情况,为制定更精准的屈光性白内障手术规划提供参考,对散光型IOL的定位、度数计算以及多焦点类IOL的选择有重要意义。本文将对白内障术前角膜散光检查种类和检查设备新进展进行综述。

Analysis of the regional spectral properties in northwestern South China Sea based on an empirical orthogonal function

This study presents an analysis of the spectral characteristics of remote sensing reflectance(Rrs)in northwestern South China Sea based on the in situ optical and water quality data for August 2018.Rrswas initially divided into four classes,classes A to D,using the max-classification algorithm,and the spectral properties of whole Rrs were characterized using the empirical orthogonal function(EOF)analysis.Subsequently,the dominant factors in each EOF mode were determined.The results indicated that more than 95%of the variances of Rrs are partly driven by the back-scattering characteristics of the suspended matter.The initial two EOF modes were well correlated with the total suspended matter and back-scattering coefficient.Furthermore,the first EOF modes of the four classes of Rrs(A-D Rrs-EOF1)significantly contributed to the total variances of each Rrs class.In addition,the correlation coefficients between the amplitude factors of class A-D Rrs-EOF1 and the variances of the relevant water quality and optical parameters were better than those of the unclassified ones.The spectral shape of class ARrs-EOF1 was governed by the absorption characteristic of chlorophyll a and colored dissolved organic matter(CDOM).The spectral shape of class B Rrs-EOF1 was governed by the absorption characteristic of CDOM since it exhibited a high correlation with the absorption coefficient of CDOM(ag(λ)),whereas the spectral shape of class C Rrs-EOF1 was governed by the back-scattering characteristics but not affected by the suspended matter.The spectral shape of class D Rrs-EOF1 exhibited a relatively good correlation with all the water quality parameters,which played a significant role in deciding its spectral shape.

Strengthening effect of super typhoon Rammasun(2014)on upwelling and cold eddies in the South China Sea

Typhoon is one of the frequent natural disasters in coastal regions of China.As shown in many studies,the impact of typhoons on the South China Sea(SCS)should not be overlooked.Super typhoon Rammasun(2014)was studied that formed in the northwestern Pacific,passed through the SCS,then landed in the Leizhou Peninsula.Remote sensing data and model products were used to analyze the spatiotemporal variations of the cold eddies,upwelling,sea surface temperature,mixed layer depth,rainfall,sea surface salinity,suspended sediment concentration,and surface-level anomaly.Results confirm the constant presence of upwelling and cold eddies in the southeast of Hainan(north of the Zhongsha Islands)and the southeast of Vietnam in July.In addition,we found the strengthening effect of super typhoon Rammasun on the upwelling and cold eddies in the SCS.The major reasons for the continuous decrease in sea surface temperature and the slow regaining of seawater temperature were the enhanced upwelling and vertical mixing caused by the typhoon.The increasing of the surface runoff in the Indochina Peninsula was mainly affected by the typhoon,with some contribution for the southeast of Vietnam’s cold eddy and upwelling.

Proposal of a new T-stage classification system for ampullary carcinoma based on Surveillance,Epidemiology and End Result(SEER)database

Background:Tumor size is still considered a useful prognostic factor in currently available tumor-nodemetastasis(TNM)classification staging systems for most solid tumors,but the significance of tumor size on the prognosis of ampullary carcinoma remains controversial.The aim of the current study was to propose a new T-stage classification system for ampullary carcinoma to address the impact of tumor size on the prognostic outcome.Methods:Using the Surveillance,Epidemiology,and End Results(SEER)database,we identified 1080 patients with ampullary carcinoma who underwent radical surgical resection between 2004 and 2015.Based on the results obtained from analysis of various clinicopathologic factors,a new T-stage classification system was proposed.Results:Among the 1080 patients,618 were men and 462 were women,with a median tumor size of 2.3(range 0.1–12)cm.Using the 7 th edition of the American Joint Committee on Cancer(AJCC)staging manual,we noticed significant differences in overall survival(OS)between T2 vs.T3 tumors(P<0.001)and T3 vs.T4 tumors(P=0.002),but failed to observe significant differences between T1 vs.T2 tumors(P=0.498)in our pair-wise comparison.Using the newly developed T-stage classification system,we were able to differentiate significant differences in OS between T1 vs.T2 tumors(P=0.032),T2 vs.T3 tumors(P<0.001)and T3 vs.T4 tumor(P=0.003)in all pair-wise comparisons.The c-index of the new staging system was 0.653(95%CI:0.629–0.677),showing a better discriminatory power than the 0.636 of the 7 th AJCC staging system(95%CI:0.612–0.660).Conclusions:The new T-stage classification system described herein can better differentiate prognostic outcomes after radical resection in patients with ampullary carcinoma by incorporating tumor size and depth of tumor infiltration.

微血管侵犯及手术切缘对肝细胞癌患者术后生存预后的影响

目的:探讨微血管侵犯(MVI)及手术切缘对肝细胞癌(HCC)术后生存预后的影响。方法:回顾性分析2016年1月至2020年12月佛山市第一人民医院收治的513例HCC肝切除患者临床资料。患者均签署知情同意书,符合医学伦理学规定。其中男419例,女94例;年龄25~86岁,中位年龄54岁。MVI分为3个等级:M0(无MVI组)、M1(低危组)、M2(高危组)。肿瘤切缘分为窄切缘(<1 cm)、宽切缘(≥1 cm)。采用χ^(2)检验及Logistic回归多因素分析HCC患者MVI发生的影响因素。生存分析采用Kaplan-Meier法和Log-rank检验。结果:单因素分析显示,AFP、肿瘤直径、肿瘤数目、CNCL与HCC患者MVI发生有关(χ^(2)=28.068,29.657,4.375,10.208;P<0.05)。Logistic回归多因素分析显示,AFP、肿瘤直径是HCC患者MVI发生的独立影响因素(OR=0.408,0.394;P<0.05)。M0组术后1、2、3年无瘤生存率分别为79.6%、71.0%、63.4%,M1组相应为59.6%、48.0%、43.3%,M2组相应为31.0%、27.5%、25.2%,差异有统计学意义(χ^(2)=61.889,P<0.05)。M0组术后1、2、3年总体生存率分别为97.3%、88.2%、84.6%,M1组相应为87.0%、71.5%、66.1%,M2组相应为79.3%、61.9%、52.6%,差异有统计学意义(χ^(2)=44.138,P<0.05)。对于MVI阴性患者,宽切缘组术后1、2、3年无瘤生存率分别为82.6%、70.7%、65.4%,而窄切缘组相应为79.4%、64.7%、60.5%,差异无统计学意义(χ^(2)=0.983,P>0.05);宽切缘组术后1、2、3年总体生存率分别为97.5%、89.6%、85.2%,而窄切缘组相应为97.1%、86.0%、82.8%,差异无统计学意义(χ^(2)=0.051,P>0.05)。对于MVI阳性患者,宽切缘组术后1、2、3年无瘤生存率分别为58.1%、45.4%、40.3%,而窄切缘组相应为42.9%、37.3%、36.1%,差异有统计学意义(χ^(2)=4.874,P<0.05);宽切缘组术后1、2、3年总体生存率分别为88.8%、71.9%、64.3%,窄切缘组相应为82.6%、64.8%、61.0%,差异有统计学意义(χ^(2)=4.604,P<0.05)。结论:肿瘤大小、AFP是HCC患者发生MVI的独立危险因素。MVI分级越高,患者预后越差。对于MVI阳性患者,肿瘤切缘宽者长期预后优于切缘窄者;而对于MVI阴性患者,肿瘤切缘对预后无明显影响。

腹腔镜右半肝切除术治疗肝癌的安全性与疗效

目的探讨腹腔镜右半肝切除术(LRH)治疗肝细胞癌(肝癌)的安全性和疗效。方法回顾性分析2014年1月至2020年7月佛山市第一人民医院收治的85例肝癌患者临床资料。患者均签署知情同意书,符合医学伦理学规定。其中男75例,女10例;年龄29~74岁,中位年龄52岁。肝功能均为Child-Pugh分级A级,肿瘤直径<8 cm。根据手术方式不同分为LRH组与开腹右半肝切除术(ORH)组,两组均采用标准化、流程化前入路右半肝切除术。两组手术时间、术后住院时间等比较采用t检验或秩和检验,术后并发症等率的比较采用χ2检验或Fisher确切概率法,生存分析采用Kaplan-Meier法和Log-rank检验。结果LRH组平均手术时间为(332±52)min,明显长于ORH组的(287±59)min(t=3.316,P<0.05)。LRH组术后肛门排气时间为(1.5±0.9)d,明显短于ORH组的(2.8±0.8)d(t=-3.119,P<0.05)。LRH组术后住院时间中位数为9(2)d,明显短于ORH组的12(4)d(Z=-3.210,P<0.05)。LRH组无围手术期死亡,ORH组围手术期死亡2例,差异无统计学意义(P=0.508)。LRH组术后并发症发生率为16%(4/25),ORH组为33%(20/60),差异无统计学意义(χ2=2.617,P>0.05)。LRH组无肝切缘旁复发,腹腔种植性转移1例;ORH组肝切缘旁复发1例,腹腔种植性转移2例,切缘旁复发差异无统计学意义(P=1.000),腹腔种植性转移差异亦无统计学意义(χ2=0.243,P>0.05)。LRH组术后1、3年无瘤生存率分别为72.0%、62.6%,ORH组相应为65.6%、41.0%,差异无统计学意义(χ2=2.835,P>0.05)。LRH组术后1、3年总体生存率分为96.0%、75.4%,ORH组相应为88.3%、76.5%,差异亦无统计学意义(χ2=0.016,P>0.05)。结论标准化、流程化前入路LRH治疗肝癌安全、可行,具有微创、术后恢复快等优势,在无瘤生存及总体生存等方面与ORH相当。