Linearity,symmetry and additivity of the human eye-movement response to maintained unilateral and bilateral surface galvanic (DC) vestibular stimulation

Recent studies have shown that, although responses to long-duration, constant-current surface galvanic vestibular stimulation (GVS) show substantial interindividual variability, individual subjects show a reliable, repeatable, idiosyncratic oculomotor response pattern to GVS. It follows that GVS may be a more reliable stimulus than may have been anticipated from the literature. The aim of the present study was to examine the metrics of 3D eye-movement responses to maintained (120 s), unilateral and bilateral surface GVS. Eye movements were measured using computerised video-oculography. Two experiments were conducted: Experiment 1 examined whether the normal response is linear over increasing levels of current; and Experiment 2 examined (1) whether the normal response to surface GVS is symmetrical when comparing stimulated sides, (2) whether the normal response to surface GVS is symmetrical when the polarity of the stimulating current was reversed, and (3) whether there is additivity in the normal response to combinations of unilateral/bilateral surface GVS. Five subjects participated in Experiment 1 and eight subjects participated in Experiment 2. In both experiments, the onset of stimulation produced characteristic eye-movement responses: changes in torsional position with the upper pole of both eyes rolling towards the anode and away from the cathode; together with horizontal and torsional nystagmus with slow phases towards the anode and away from the cathode; and negligible vertical nystagmus. These responses reversed direction at stimulus offset. In the fixation condition of Experiment 1, the magnitude of ocular torsional position (OTP) and torsional nystagmus responses showed a linear relationship over conditions of increasing current strength, as did OTP, torsional and horizontal nystagmus responses in darkness. The results of Experiment 2 showed that responses to unilateral stimulation are symmetrical between stimulated sides, symmetrical between stimulating polarities, and additive (with respect to responses to bilateral stimulation). The principles derived from these findings, as well as those of recent studies, provide a foundation for future work investigating eye-movement responses to surface GVS in patients with known types of vestibular dysfunction. Electronic Publication     

Critical values for linearity tests in time‐varying smooth transition autoregressive models when data are highly persistent

Summary In this paper, we derive asymptotic distributions for linearity tests in time‐varying smooth transition autoregressive models in the presence of a unit root. The limiting distributions are non‐standard because of the unit root assumption, and it is shown that the linearity hypothesis is rejected far too often (up to 30.9% of the times at a 5% significance level) when using critical values from a chi‐square distribution.     

CELL-DYN3700血液分析仪的应用评价

目的对CELL-DYN3700(CD3700)血液分析仪的性能进行评价。方法参照美国临床实验室标准化委员会(NCCLS)和国际血液学标准化委员会(ICSH)文件的评价方法,对仪器的精密度、携带污染率、线性及白细胞分类等性能指标进行评价。结果CD3700血液分析仪的精密度和携带污染率都小于仪器设置的要求,线性范围能够较好地满足临床的需要,对白细胞分类结果与人工法结果有较好的相关性。结论CD3700血液分析的性能指标良好,可满足临床需要。     

化学发光检验线性评价与应用

探讨EP6-A、CAP-IRC和改良的Doumas等三种线性评价方法的区别和适用性及在化学发光检验中的应用。采用CAP-IRC、EP6-A、改良的Doumas等三种方法对8个化学发光检验项目进行线性评价,比较评价结果的异同。结果显示：在8个化学发光检验项目中,EP6-A方法和CAP-IRC方法均有5个可直接判断为线性,2个为临床可接受线性,1个为非线性;改良的Doumas方法有3个为线性,5个为非线性。结论：改良的Doumas方法不适用于临床化学发光检验线性评价。     

TLD linearity vs. beam energy and modality

Thermoluminescent dosimetry (TLD) is considered to be a valuable dosimetric tool in determining patient dose. Lithium fluoride doped with magnesium and titanium (TLD-100) is widely used, as it does not display widely divergent energy dependence. For many years, we have known that TLD-100 shows supralinearity to dose. In a radiotherapy clinic, there are multiple energies and modality beams. This work investigates whether individual linearity corrections must be used for each beam or whether a single correction can be applied to all beams. The response of TLD as a function of dose was measured from 25 cGy to 1000 cGy on both electrons and photons from 6 to 18 MeV. This work shows that, within our measurement uncertainty, TLD-100 exhibits supralinearity at all megavoltage energies and modalities.     

Telomeric structures in a linear mitochondrial plasmid from Physarum polycephalum

Summary A mitochondrial plasmid was isolated from Physarum polycephalum and characterized by restriction mapping. Cloned fragments of the plasmid were assembled and used to construct a restriction map. This plasmid was a linear molecule with telomeric structures at each end. Southern hybridization with the ends of the plasmid as probes revealed that the plasmid included repeating units at both ends, with each unit being approximately 125 bp in length. The most extensive array of repeats consisted of at least 17 repetitions of the 125-bp unit. The sensitivity of these repeats to Bal31 exonuclease confirmed that they were at, or very near to, the ends of the plasmid. From the extent of the repetitions, the size of the plasmid was estimated to vary from 13.3 kbp to more than 18.3 kbp.     

用自制新型荧光剂EPQS标记蛋白质及其荧光纸层析扫描测定

用自行研制的新型水溶性荧光剂EPQS分别标记人血清白蛋白(HSA)、牛血清白蛋白(BSA)和猪胰岛素(Insulin),经乙酸纤维素薄膜电泳纯化后,作荧光纸层析扫描,测得EPQS-HSA、EPQS-BSA和EPQS-Insulin的荧光光谱(λ_(em))分别为470、465、468nm,激发光谱(λ_(ex))分别为370、373、371nm;EPQS的λ_(em)为476nm,λ_(ex)为382nm。表明EPQS能用于蛋白质的标记。用EPQS定量HSA,结果显示,1～5μg的EPQS-HSA作荧光纸层析扫描,其结果与荧光强度有良好的线性关系。     

三种抗环瓜丝氨酸抗体检测试剂性能评价及临床应用

目的评价3种抗环瓜丝氨酸(CCP)抗体检测试剂盒的分析性能,并比较临床应用。方法收集93例类风湿性关节炎(RA)患者、118例非RA疾病(自身免疫性疾病82例、骨关节炎36例)患者以及20名表面健康人群的血清样本,评价罗氏、欧蒙、富纯3种抗CCP抗体试剂的分析性能,比较不同试剂间的相关性,评估各自的初步临床应用价值。结果 3种试剂检测精密度差异无统计学意义,批内、天间变异系数(CV)均<10%。罗氏和欧蒙2种试剂在检测范围内呈线性,富纯试剂的真实线性范围为25.0～1 027.9 RU/mL。3种试剂检测结果相关性较好,罗氏与欧蒙、富纯试剂的相关系数(r)分别为0.90、0.87,欧蒙、富纯试剂的相关系数(r)为0.97。根据厂商提供的Cut-off值,诊断灵敏度可达83.9%～86.0%,特异性为92.0%～97.1%。罗氏、欧蒙、富纯检测试剂的受试者工作特征(ROC)曲线下面积(AUC)分别为0.91、0.92和0.89,比较任意2种检测试剂的AUC,差异均无统计学意义(Z值分别为0.27、0.89、0.63,P均>0.05)。结论总体来说,不同方法抗CCP抗体检测试剂的检测结果之间具有一定的可比性,临床应用的诊断特性差异不明显,但标准化仍存在问题。     

Practical Risk Assessment and Management Issues Arising were we to Adopt Low-Dose Linearity for all Endpoints

The 2009 National Research Council report, Science and Decisions, proposes harmonizing dose-response approaches for cancer and non-cancer endpoints, and for non-cancer quantitative risk assessment, this would usually take the form of a low-dose linear no-threshold dose-response curve. The soundness of this recommendation has been questioned, but I focus on its consequences if adopted, many of them apparently unintended. If most endpoints for most agents are assumed to have non-zero low-dose risks, then the critical-effect concept, choosing the one endpoint on which to calculate acceptable doses, loses its basis. All regulatory decisions, since they entail substituting some exposures (and their attendant risks) for others, become risk-risk trade-off decisions, and equity questions are raised since risk transfer is inevitably involved. A valid basis for estimating low-dose linear components is not evident, and upper-bound approaches fail to be reliably public health-protective owing to the risk trade-off decisions that need to be faced.     

Linearity study on detection and quantification limits for the determination of avermectins using linear regression

In this study, linear relationships between response and concentration were used to estimate the detection limit (DL) and quantification limit (QL) for five avermectins: emamectin, abamectin, doramectin, moxidectin, and ivermectin. Estimation of DL and QL was based on the standard deviation of residual and y-intercept of the regression line at low concentrations of avermectins, using the dispersive solid-phase extraction procedure. Avermectin extracts were analyzed using liquid chromatography tandem mass spectrometry. Based on the regression slope, DL and QL were higher at concentrations of 0.3–0.4 μg/kg and 1 μg/kg, respectively, for all avermectin compounds. Linearity assessment was performed by linear regression, which incorporated a regression model, outlier rejection, and evaluation of the assumption with a significant test. For all avermectins, there is a significant correlation between response and concentration in the range 1–15 μg/kg, and the y-intercept passes through origin (zero).