居民主要食入蔬菜中210Po含量及所致公众内照射剂量估算

目的 为了调查市售蔬菜中²¹⁰Po的放射性水平,评价其对居民的影响。方法 通过市场购买叶菜类、果菜类等14种蔬菜,使用湿式消解与银片自沉积结合的方法测量各种蔬菜中²¹⁰Po活度浓度水平,与相关文献中的参考值进行对比,并进行内照射剂量估算。结果 此次研究所选取的14种蔬菜中,活度浓度范围在8.34×10^-3～1.27 Bq/kg（鲜）。菌类的香菇²¹⁰Po含量最高,为1.27 Bq/kg,高于其他几类蔬菜,叶菜类²¹⁰Po含量其次,范围在1.30×10^-2～1.74×10^-1 Bq/kg,根茎类的两种蔬菜活度浓度范围在1.77×10^-2～3.51×10^-2 Bq/kg,果菜类六种蔬菜范围在8.34×10^-3～6.19×10^-2 Bq/kg。经估算居民通过这14种蔬菜摄入²¹⁰Po的量为24.3 Bq/a,所致内照射剂量29.2 μSv/a。结论 此次调查的市售蔬菜中²¹⁰Po水平属于正常水平,不会对居民健康产生影响。     

老年心力衰竭的康复护理评估

目的：对老年充血性心力衰竭患者作深入的护理评估,提高护理质量。方法：１０ａ内收治的充血性心力衰竭患者分成两组,年龄≥６０岁组（老年组）,年龄＜６０岁组（成年组）,比较两组发病诱因、症状、体征、电解质、治疗情况,结果作ｔ检验。结果：呼吸道感染是老年组充血性心力衰竭患者发病主要诱因。神经精神症状、夜间阵发性呼吸困难、洋地黄中毒、电解质紊乱发生率老年组明显高于成年组（Ｐ＜０．０５）。结论：对老年充血性心力衰竭患者进行评估时,护理人员对患者生命体征变化机理的理解能力和疾病涉及器官功能状态分析能力是促进护理成功的关键。     

Benign breast disease increases breast cancer risk independent of underlying familial risk profile: Findings from a Prospective Family Study Cohort

Benign breast disease (BBD) is an established breast cancer (BC) risk factor, but it is unclear whether the magnitude of the association applies to women at familial or genetic risk. This information is needed to improve BC risk assessment in clinical settings. Using the Prospective Family Study Cohort, we used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of BBD with BC risk. We also examined whether the association with BBD differed by underlying familial risk profile (FRP), calculated using absolute risk estimates from the Breast Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) model. During 176,756 person-years of follow-up (median: 10.9 years, maximum: 23.7) of 17,154 women unaffected with BC at baseline, we observed 968 incident cases of BC. A total of 4,704 (27%) women reported a history of BBD diagnosis at baseline. A history of BBD was associated with a greater risk of BC: HR = 1.31 (95% CI: 1.14–1.50), and did not differ by underlying FRP, with HRs of 1.35 (95% CI: 1.11–1.65), 1.26 (95% CI: 1.00–1.60), and 1.40 (95% CI: 1.01–1.93), for categories of full-lifetime BOADICEA score <20%, 20 to <35%, ≥35%, respectively. There was no difference in the association for women with BRCA1 mutations (HR: 1.64; 95% CI: 1.04–2.58), women with BRCA2 mutations (HR: 1.34; 95% CI: 0.78–2.3) or for women without a known BRCA1 or BRCA2 mutation (HR: 1.31; 95% CI: 1.13–1.53) (p_interaction = 0.95). Women with a history of BBD have an increased risk of BC that is independent of, and multiplies, their underlying familial and genetic risk.     

Optimization of nonlinear dose- and concentration-response models utilizing evolutionary computation

An essential part of toxicity and chemical screening is assessing the concentrated related effects of a test article. Most often this concentration-response is a nonlinear, necessitating sophisticated regression methodologies. The parameters derived from curve fitting are essential in determining a test article's potency (EC(50)) and efficacy (E(max)) and variations in model fit may lead to different conclusions about an article's performance and safety. Previous approaches have leveraged advanced statistical and mathematical techniques to implement nonlinear least squares (NLS) for obtaining the parameters defining such a curve. These approaches, while mathematically rigorous, suffer from initial value sensitivity, computational intensity, and rely on complex and intricate computational and numerical techniques. However if there is a known mathematical model that can reliably predict the data, then nonlinear regression may be equally viewed as parameter optimization. In this context, one may utilize proven techniques from machine learning, such as evolutionary algorithms, which are robust, powerful, and require far less computational framework to optimize the defining parameters. In the current study we present a new method that uses such techniques, Evolutionary Algorithm Dose Response Modeling (EADRM), and demonstrate its effectiveness compared to more conventional methods on both real and simulated data.     

Differential effects of advance semantic cues on grasping, naming, and manual estimation

In the three experiments reported here, we systematically investigated when and/or how prior semantic information about a target-object would affect the programming and execution of grasping movements. A name-length association was first created during a practice phase while participants performed one of the three tasks: grasping, naming, or manual estimation of an object’s length upon an auditory presentation of its name. In the subsequent test phase, in the majority of trials, these names correctly indicated the upcoming object for a grasping task or a control naming task (Experiment 1A and 1B), and a grasping task or a manual estimation of object length (Experiment 2). In both experiments, a name was occasionally incongruent or a neutral cue (a burst of white noise) was presented instead. Although in the grasping task, semantic cues (both congruent and incongruent) consistently facilitated movement-onset time (indicating a preparatory-set like effect), the impact of these cues on the formation of grasping aperture was less consistent or absent. The experiments also demonstrated that naming and perceptual estimation of object length were affected differently from grasping by the same semantic cues, with the congruent cues facilitating and the incongruent cues slowing down response onset. These findings reinforce and extend the proposal that the transformations of visual and semantic information for perceptually-driven tasks are quite different from the transformations of the same information for the programming and control of object-directed action.     

BED-CEIA估计HIV-1新近感染率的有效性及其影响因素的评价

在艾滋病流行病学研究中,衡量艾滋病流行趋势最常用的指标是HIV累积感染率和新近感染率.与累积感染率相比,新近感染率对艾滋病流行趋势预测、干预效果评价以及防制策略的制定等能提供更直接的信息.在获取新近感染率的方法中,除了经典的流行病学队列随访方法,目前普遍使用的血清学方法之一是IgG捕获BED酶联免疫法(BED-CEIA).2001年,美国疾病预防控制中心(CDC)艾滋病免疫和诊断室评估了16种基于不同抗体和原理的HIV-1新近感染检测方法,发现新近感染者与既往感染者相比,各种抗体滴度均较低;其中gp41抗体滴度在新近感染者和既往感染者中的差别最大,两者的滴度区间几乎没有重叠,新近感染者的gp41抗体亲和力低于既往感染者,从而认为gp41抗体能够区分新近感染者和既往感染者,并且酶联免疫实验操作相对简单、效果也较理想,因此该室着手开发基于gp41抗体的HIV-1新近感染检测的酶联免疫方法[1].     

创伤性脑损伤后细胞凋亡的时相性研究

目的探讨创伤性脑损伤中细胞凋亡的发生发展过程,为脑损伤后的神经系统保护提供实验资料以及为法医学损伤经过时间推断提供帮助。方法以Feeney自由落体脑损伤大鼠模型为对象,采用DNA缺口末端标记法（TUNEL）染色观察不同损伤时间时脑损伤组脑组织、假手术对照组脑组织和正常对照组脑组织中细胞凋亡的情况。结果创伤性脑损伤后2h即可在伤侧皮层以及同侧的海马区可见细胞凋亡发生,随着损伤经过时间的延长,凋亡细胞逐渐增多,在48~72h凋亡达到高峰,随之逐渐减少,至7d时凋亡数仍显著高于正常对照组和假手术组,正常对照组和假手术组在伤侧对应区和海马区仅偶见凋亡细胞。结论检测损伤区凋亡细胞数对损伤经过时间的推断有重要价值,为法医学损伤诊断起重要作用。     

Effects of Various Parameters on Lateral Displacement Estimation in Ultrasound Elastography

Complementary to axial, lateral displacement and strain can provide important information on the biological soft tissues. In this paper, the effects of key parameters (i.e., lateral displacement, pitch, beamwidth, beam overlap and interpolation) on lateral displacement estimation were investigated, in simulations and homogeneous phantom experiments, using lateral rigid motion only to study its fundamentals separately from the effects of axial motion and 2-D deformation on lateral displacement estimation. The performance of the lateral motion estimator was evaluated by measuring its associated bias, jitter and correlation coefficient. Simulation results showed that the bias and jitter of the lateral displacement estimation and correlation coefficient of RF signals undergo periodic variations depending on the lateral displacement, with a period equal to the pitch. The performance of the lateral estimation was improved when a smaller pitch or a larger beamwidth, was used. The effect of the pitch on the lateral estimation on lateral displacement estimation was found to be greater than the beamwidth effect. Therefore, a smaller pitch is preferred when the beam overlap remains the same. The use of cubic spline, instead of linear interpolation, increases the correlation coefficient, and decreases the jitter, with the trade-off of increased bias. The results of the phantom experiments were shown in good agreement with the simulation findings, including the periodic variation of the performance with lateral displacement and effects of pitch, beamwidth and interpolation method on lateral displacement estimation. In conclusion, smaller pitch, wider beamwidth and spline interpolation were shown to be key in reducing the jitter error in the lateral displacement estimation. (E-mail: ek2191@columbia.edu)