Screening Effect of the Diffusive Boundary Layer in Sediments of Lake Aha in the Suburbs of Guiyang City, Guizhou Province

The redox cycle of iron and manganese is a major geochemical process at the boundary layers of lake sediments. Lake Aha, which lies in the suburbs of Guiyang City,Guizhou Province, China, is a medium-sized artificial reservoir with seasonally anoxic hypolimnion. Long-term sedimentary accumulation of iron and manganese resulted in their enrichment in the upper sediments. In the anoxic season, Fe2+ and Mn2+, formed by biological oxidation, would diffuse up to overlying waters from sedlments. However, the concentration of Fe2+ increased later and decreased earlier than that of Mn2+. Generally, sulfate reduction occurred at 6 cm below the sediment-water interface. Whereas, in the anoxic season, the reduction reached upper sediments, inhibiting the release of Fe2+. The Fe concentration of anoxic water is quickly decreased from high to low as a result of reduction Of the sulphur system.

Assessing the Effectiveness of a Cervical Cancer Screening Program in a Hospital-based Study

This study compared HPV testing and liquid-based cytology （LCT） as performance indicators for cervical cancer screening in a hospital-based study. A total of 61,193 outpatients were screened initially by LCT. Samples with screening results showing atypical squamous cells of undetermined significance （ASC-US） or worse were referred for colposcopy, and some samples were tested for high-risk HPV types with the Hybrid Capture II system （HC II）. Data on LCT （n=61,193） and HC II （n=1056） results were analysed. Overall test positivity for LCT was 2.53% using an ASC-US threshold, 3.11% using a low-grade squamous intraepithelial lesion （LSIL） threshold, and 0.67% using a high-grade squamous intraepithelial lesion （HSIL） threshold. A total of 1839 women （84% of the 3893 patients with abnormal cytology） underwent colposcopy-directed biopsy. HPV was positive in 80.3% of women with cervical intraepithelial neoplasia 1 （CIN1）, 88.3% of those with CIN2, 79.2% of women with CIN3 and 50% （2 of 4） of women with invasive cancer. There was a significant increase in the detection of CIN2 or worse with adjunct HPV testing of women with ASC-US and LSIL However, there were detection of CIN2＋ cases no differences in the with adjunct HPV testing of women with HSlI.. The results indicate that HPV testing for HSlL triage should not be recommended in cervical cancer screening.

Screening influence on the Stark effect of impurity states in strained wurtzite GaN/Al_xGa_(1-x)N heterojunctions under pressure

The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. The variations of Stark energy shift with electric field, impurity position, A1 component and areal electron density are discussed. Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states. For a given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. The weakening of the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field. Furthermore, the screening effect weakens the mixture crystal effect, thereby influencing the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.

The effect of dynamical screening on helium(e,2e) fully differential cross-sections

This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dynamically screened three-Coulomb-wave theory. Comparisons are made with the experimental data and those of the three-Coulomb wave function model and second-order distorted-wave Born method. The angular distribution and relative heights of the present FDCS is found to be in very good agreement with the experimental data in the perpendicular plane geometry. It is shown that dynamical screening effects are significant in this geometry. Three-body coupling is expected to be weak in the coplanar geometry, although the precise absolute value of the cross section is still sensitive to the interaction details.

Cost-effectiveness analysis of population-based screening of hepatocellular carcinoma: Comparing ultrasonography with two-stage screening

AIM: To assess the cost-effectiveness of two populationbased hepatocellular carcinoma(HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography(AUS).METHODS: In this study, we applied a Markov decision model with a societal perspective and a lifetime horizon for the general population-based cohorts in an area with high HCC incidence, such as Taiwan. The accuracy of biomarkers and ultrasonography was estimated from published meta-analyses. The costs of surveillance, diagnosis, and treatment were based on a combination of published literature, Medicare payments, and medical expenditure at the National Taiwan University Hospital. The main outcome measure was cost per lifeyear gained with a 3% annual discount rate. RESULTS: The results show that the mass screening using AUS was associated with an incremental costeffectiveness ratio of USD39825 per life-year gained, whereas two-stage screening was associated with an incremental cost-effectiveness ratio of USD49733 per life-year gained, as compared with no screening. Screening programs with an initial screening age of 50 years old and biennial screening interval were the most cost-effective. These findings were sensitive to the costs of screening tools and the specificity of biomarker screening.CONCLUSION: Mass screening using AUS is more cost effective than two-stage biomarker-ultrasound screening. The most optimal strategy is an initial screening age at 50 years old with a 2-year inter-screening interval.

Plasma-screening effects on positronium formation

Plasma-screening effects on positronium （Ps） formation for positron-hydrogen collisions in a Debye plasma environ- ment is further investigated using the screening approximation model with the inclusion of the modified structure of Ps. More accurate Ps formation cross sections （n = 1,2） are obtained for various Debye lengths from the Ps formation thresh- olds to 50 eV. The influence of considering modified bound-state wave functions and eigenenergies for the Ps is found to result in the reduction of the Ps formation cross sections at low energies, whereas it cannot counteract the enhancement of the Ps formation by the Debye screening.

Higher Order Multipole Potentials and Electrostatic Screening Effects on Cohesive Energy and Bulk Modulus of Metallic Nanoparticles

Higher order multipole potentials and electrostatic screening effects are introduced to incorporate the dangling bonds on the surface of a metallic nanopaticle and to modify the coulomb like potential energy terms,respectively. The total interaction energy function for any metallic nanoparticle is represented in terms of two- and three-body potentials. The two-body part is described by dipole-dipole interaction potential,and in the three-body part,triple-dipole (DDD) and dipole-dipole-quadrupole(DDQ) terms are included.The size-dependent cohesive energy and bulk modulus are observed to decrease with decreasing sizes,a result which is in good agreement with the experimental values of Mo and W nanoparticles.

Cancer screening:Between appropriateness and effectiveness

Two similar words, effectiveness and efficacy, have comparable insight and nearly describe analogous mea-ning for a screening test, yet clear understanding and perception of their diverse meanings will help clarify the basis of the differing conclusions about whether screening tests for different cancers reduce morbidity and mortality. Screening test may not be effective even when it sounds to be efficacious, on the other hand it should be efficacious when the test is effective.

What is the most cost-effective strategy to screen for second primary colorectal cancers in male cancer survivors in Korea?

AIM:To identify a cost-effective strategy of second primary colorectal cancer (CRC) screening for cancer survivors in Korea using a decision-analytic model.METHODS: A Markov model estimated the clinical and economic consequences of a simulated 50-year-old male cancer survivors' cohort, and we compared the results of eight screening strategies: no screening, fecal occult blood test (FOBT) annually, FOBT every 2 years, sigmoidoscopy every 5 years, double contrast barium enema every 5 years, and colonoscopy every 10 years (COL10), every 5 years (COL5), and every 3 years (COL3). We included only direct medical costs, and our main outcome measures were discounted lifetime costs, life expectancy, and incremental cost-effectiveness ratio (ICER).RESULTS: In the base-case analysis, the non-dominated strategies in cancer survivors were COL5, and COL3. The ICER for COL3 in cancer survivors was $5593/life-year saved (LYS), and did not exceed $10000/LYS in one-way sensitivity analyses. If the risk of CRC in can- cer survivors is at least two times higher than that in the general population, COL5 had an ICER of less than $10500/LYS among both good and poor prognosis of index cancer. If the age of cancer survivors starting CRC screening was decreased to 40 years, the ICER of COL5 was less than $7400/LYS regardless of screening compliance.CONCLUSION: Our study suggests that more strict and frequent recommendations for colonoscopy such as COL5 and COL3 could be considered as economically reasonable second primary CRC screening strategies for Korean male cancer survivors.

Mass scale screening of common arboviral infections by an affordable,cost effective RT-PCR method

Objective:To develop a rapid,cost effective RT-PCR method for the mass scale diagnosis of such diseases at the vireraia stage to find out the actual disease burden in that area.Methods:For this purpose,cases with the history of only short febrile illness were considered.Thus 157 samples with the history of dengue/chikungunya like illness and only 58 samples with a history of acute encephalitis syndrome(AES)were selected.Results:Out of 157 samples,42 and 74 were detected as dengue and chikungunya,respectively and out of 58 AES cases only 23 could be detected as Japanese encephalitis by this RT-PCR method.Conclusions:This cost effective RT-PCR method can detect the total positive cases that remain undetected by EL1SA method.Moreover,this method is capable to detect the viral RNA from patients'sera even after the appearance of IgM antibody at one fifth costs as compared with the other commercially available kits.

Temperature effect on dissipative holographic screening-photovoltaic solitons in a biased dissipative system

In a biased dissipative photovoltaic-photorefractive system, this paper investigates the temperature effect on the evolution and the self-deflection of the dissipative holographic screening-photovoltaic （DHSP） solitons. The results reveal that, the evolution and the self-deflection of the bright and dark DHSP solitons are influenced by the system temperature. At a given temperature, for a stable DHSP soliton originally formed in the dissipative system, it attempts to evolve into another DHSP soliton when the temperature change is appropriately small, whereas it will become unstable or break down if the temperature departure is large enough. Moreover, the self-deflection degree of the solitary beam centre increases as temperature rises in some range, while it is decided by the system parameters and is slight under small-signal condition. The system temperature can be adjusted to change the formation and the self-deflection of the solitary beam in order to gain certain optical ends. In a word, the system temperature plays a role for the DHSP solitons in the dissipative system.

咖啡锈病发生规律调查及施药适期研究

为筛选出防治咖啡锈病的有效杀菌剂,明确其施药适期,以提高防治效果,笔者调查咖啡锈病发生规律,在温室采用先接种后施药和先施药后接种的方法测试4种杀菌剂的防治效果,并验证筛选药剂的田间防治效果。结果表明:咖啡锈病发生盛期为10月至翌年3月。叶片接种夏孢子后72 h喷施4种杀菌剂,一定浓度的4种杀菌剂均有较好的治疗和预防效果。接种病原菌后10 d施用75%戊唑·嘧菌酯水分散粒剂(WG)3000倍液和25%嘧菌酯悬浮剂(SC)1500倍液,治疗效果分别为94.19%和83.87%;75%戊唑·嘧菌酯WG 3000倍液和25%嘧菌酯SC 1500倍液具有较好的预防效果,预防持效期分别为15 d和10 d。间隔9 d施药3次后田间防治39 d和68 d,75%戊唑·嘧菌酯WG 3000倍液相对防效分别为92.00%和81.08%,25%嘧菌酯SC 1500倍液的相对防效分别为88.29%和69.05%。可依据咖啡锈病的发生规律适时选用75%戊唑·嘧菌酯WG和25%嘧菌酯SC。

宁夏吴忠地区胃癌机会性筛查中两种风险评分系统的效果分析

目的 比较两种胃癌风险评分系统在宁夏吴忠地区的胃癌早期筛查效果,探讨更适用于本地区胃癌早期筛查的评分系统。方法 纳入2022年5月至2023年5月在吴忠市人民医院和盐池县人民医院行胃癌机会性筛查的40~69岁患者共1 085例。分别按照北京大学肿瘤研究中心研发的上消化道恶性肿瘤风险评分系统和新胃癌筛查评分系统同时进行胃癌风险评估,比较不同评分系统对早期胃癌的筛查效果。结果 共纳入符合条件的受试对象1 085人,其中男性539人(49.68%),女性546人(50.32%),平均年龄(54.7±7.8)岁。上消化道恶性肿瘤风险评分系统高风险率(159/1 085,14.65%)低于新胃癌筛查评分系统(353/1 085,32.53%)(χ^(2)=73.51,P<0.001)。两者的筛查阳性预测值分别为4.40%和4.25%,总体一致率为74.93%(Kappa值=0.334,P<0.001)。两种胃癌风险评分系统筛查阳性者的胃镜检查结果在胃癌的分布上差异无统计学意义(χ^(2)=3.00,P=0.083)。上消化道恶性肿瘤风险评分系统的灵敏度(38.89%)、阴性预测值(98.81%)、诊断比值比(3.83)及ROC曲线下面积[0.623(95%CI:0.478~0.768)]均低于新胃癌筛查评分系统[83.33%、99.59%、10.78、0.758(95%CI:0.656~0.861)];而在特异度(85.75%)、阳性预测值(4.40%)上均高于新胃癌筛查评分系统(68.32%、4.25%);两种风险评估模型的Kappa值均为0.05。结论 在宁夏吴忠地区胃癌机会性筛查准确度方面,新胃癌筛查评分系统优于上消化道恶性肿瘤风险评分系统;但在筛查效益方面,上消化道恶性肿瘤风险评分系统优于新胃癌筛查评分系统。

复合振动筛筛分煤颗粒的离散元模拟研究

为了强化混合颗粒在筛面的分层,提高传统振动筛的筛分效果。依据混合颗粒在振动下的空隙填充效应,并基于Lissajous振动合成理论,提出了一种复合振动筛。解释了复合振动筛理论基础和工作原理,并使用离散元方法进行了验证。以复合、直线、椭圆和圆振动筛为对象,以频率、振幅和振动方向角为变量,进行了传统振动筛和复合振动筛离散元模拟对比研究,结果表明:复合振动筛在筛分效率和物料处理两方面均具有较大优势。复合振动筛可以传递给颗粒一个沿筛面宽度方向的激振力,颗粒在xyz三个方向均有激振力的作用,颗粒受力更加多样化,混合颗粒体系更加松散,活跃程度更大,分层效果更好,进而复合振动筛可以取得更为理想的筛分效果。

献血者HIV检测策略的成本效果分析

目的以多中心HIV残余风险研究为基础,分析不同HIV检测策略的成本与效果,为血站采用适宜的HIV检测策略提供参考依据。方法依据安徽省3家血站献血者HIV检测、确认情况,估算HIV不同检测方法的残余风险。建立决策树模型,分析国内现行政策下的3种不同检测策略的成本效果差异。结果本研究调查地区,抗-HIV-1+2 ELISA、HIV Ag/Ab1+2 ELISA、ELISA+NAT技术的残余风险分别为1.17×10^(-6)、0.84×10^(-6)、0.59×10^(-6);经决策树模型分析,在无核酸检测时,HIV Ag/Ab1+2 ELISA较抗-HIV-1+2 ELISA方案更具成本效果优势,但加上1遍NAT后,HIV Ag/Ab1+2 ELISA的优势消失;HIV试剂成本、HIV治疗成本以及假阳性报废成本,是模型的敏感因素。结论本研究调查地区,采用1遍抗HIV-1+2 ELISA加1遍NAT方案,具有成本效果优势。血站在决定采用何种HIV检测策略前,需对使用的酶免试剂,进行确认和评估,在保证灵敏度的前提下,综合考虑关键因素为试剂成本及试剂假阳性率。

辉长岩骨料全级配碾压混凝土力学特性研究

辉长岩坚硬致密,具有高强度、高弹模特性,但将辉长岩骨料应用于大型水电工程在国内外尚无先例,缺乏可借鉴的工程实践经验,且湿筛碾压混凝土试件的力学性能无法真实反映全级配碾压混凝土的力学特性。对辉长岩骨料最大粒径为80 mm的全级配碾压混凝土的力学特性演化规律开展了系统研究,包括抗压强度、劈拉强度、轴压性能、轴拉性能、抗剪性能等,对比分析了全级配碾压混凝土抗压、劈拉强度及其湿筛试件的尺寸效应,并将试验结果与国内典型工程所用碾压混凝土的力学性能发展规律进行对比分析,此外还建立了辉长岩骨料全级配碾压混凝土抗压强度、劈拉强度、轴压性能、轴拉性能等力学性能-养护龄期演化函数模型。结果表明:辉长岩骨料全级配碾压混凝土的抗压强度、劈拉强度、抗剪等力学性能随龄期的发展规律符合国内同类工程碾压混凝土力学性能发展的一般规律;C_(90)20W8F100辉长岩全级配碾压混凝土试件与其湿筛试件抗压强度平均尺寸效应系数为0.80、劈拉强度平均尺寸效应系数为0.66;相关力学性能演化模型相关性高(R^(2)=0.9643~0.9992)。可见辉长岩骨料用于大型水电工程碾压混凝土坝建设具有可行性。

动力煤选煤厂宽尺度煤炭干法筛分-深度分选系统研究

煤炭的筛分设备和分选设备对煤质控制起着决定性作用,对原煤特性、煤和矸石的泥化特性进行了研究分析,采用了振动测试技术、粒度级分析、密度级分析、筛分、分选效果评价等方法,介绍了弛张筛和智能跳汰分选机的性能。研究结果发现,处理能力对筛分效果影响显著,随着处理能力的增加,筛分效率有明显下降。此外,在智能跳汰分选机的研究中,发现第一段矸石中存在精煤,需要对跳汰机的智能算法进行进一步的优化。优化筛分参数和分选效果可以满足煤炭行业对高质量煤炭产品的需求,对提高煤炭筛分效率和质量控制具有实际应用意义。

射流清洗对微灌过滤器滤网清洗效果及损伤研究

为探究射流清洗技术在农业微灌过滤器清洗过程中的应用,开展射流清洗试验研究,分析入射压力、喷嘴口径、喷嘴扩散角度等3个参数对微灌过滤器滤网清洗效果及表面损伤程度的影响规律.试验结果表明:清洗效果随入射压力、喷嘴口径、喷嘴扩散角度的增大而提升,但提升幅度不断减小;滤网表面损伤程度随入射压力、喷嘴口径的增大而增大,随喷嘴扩散角度的增大而减小,其幅度逐渐减小;通过方差分析可知,射流参数对清洗效果影响程度从大到小依次为喷嘴口径、入射压力、喷嘴扩散角度,对滤网表面损伤影响程度从大到小依次为喷嘴口径、喷嘴扩散角度、入射压力;通过TOPSIS综合评价得到最佳射流参数组合为入射压力0.3 MPa,喷嘴口径3 mm,喷嘴扩散角度80°.

2020—2022年东莞市某三级公立医院两癌筛查情况分析

目的通过分析2020—2022年东莞市某三级公立医院两癌筛查情况,探讨该筛查工作的效果和意义。方法2020—2022年对东莞市户籍的35~64岁妇女或在东莞市正常参加社会基本医疗保险且连续缴费时间满5年的35~64岁的非户籍妇女开展两癌筛查。通过采集和整理大量相关数据,对东莞市某三级公立医院两癌筛查的情况进行全面分析。对筛查工作的覆盖率、阳性检出率、筛查方法的选择等进行详细的描述和评估,并对筛查工作的不足之处进行剖析。结果东莞市某三级公立医院2020—2022年子宫颈癌筛查15259名,人乳头瘤病毒(human papilloma virus,HPV)检测阳性率为6.82%,宫颈癌前病变85例,筛查出子宫颈癌1例;乳腺癌筛查15259名,乳腺彩色超声4~5级筛出率为7.82%,筛查出乳腺癌1例。结论在未来的两癌筛查工作中应该重点关注提高覆盖率和改进筛查方法,以达到更好的筛查效果。从而改善筛查工作的质量和效果,提高东莞市妇女参加筛查的积极性和满意度。