Comparative bioanalytical study of3H-deramciclane in dog plasma, using a gas chromatography-nitrogen-selective detection (GC-NPD), a new GC-radiochemical detection (GC-RD) and a liquid scintillation method

Summary A new, highly sensitive and selective gas chromatography method, using radiochemical detection (GC-DR) was developed for the selective determination of³H-labelled deramciclane and its N-desmethyl metabolite in dog plasma. Inter-day accuracy and precision, as well as system suitability of the GC-RD method was investigated during the method validation. The calibration curve was proved to be linear (r=0.9986) in a wide concentration range (13–1000 ngeqv mL⁻¹) The lower limit of quantitation (LLOQ) was 13.7 ngeqv mL⁻¹, and the limit of the detection (LOD) was 1 ngeqv mL⁻¹. Using this new GC-RD method, plasma levels of³H-labelled deramciclane and its metabolite were determined in dogs, after the administration of a single 10 mg kg⁻¹ oral dose. Pharmacokinetic curves and the calculated pharmacokinetic parameters were compared to those obtained using a previously elaborated gas chromatography-nitrogen selective detection method (GC-NPD) and to those obtained by measuring the plasma level of total radioactivity (liquid scintillation counting, LSC). Pharmacokinetic curves and the calculated pharmacokinetic parameters obtained with the two different gas chromatography detection methods (NPD and RD) showed good correlation. Comparison of these results to those acquired by total radioactivity measurement demonstrated that deramciclane was intensively metabolised. Moreover, the biological half-life (t ₁ ^2/β ) of the unknown metabolites proved to be more than a magnitude longer than the half-life of the parent compound or that of N-desmethyl metabolite. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997.     

Perturbative Power Counting,Lowest-Index Operators and Their Renormalization in Standard Model Effective Field Theory

We study two aspects of higher dimensional operators in standard model effective field theory.We first introduce a perturbative power counting rule for the entries in the anomalous dimension matrix of operators with equal mass dimension.The power counting is determined by the number of loops and the difference of the indices of the two operators involved,which in turn is defined by assuming that all terms in the standard model Lagrangian have an equal perturbative power.Then we show that the operators with the lowest index are unique at each mass dimension d,i.e.,(H~?H)~(d/2)for even d≥4,and(L~TεH)C(L~TεH)~T(H~?H)~((d-5)/2)for odd d≥5.Here H,L are the Higgs and lepton doublet,andε,C the antisymmetric matrix of rank two and the charge conjugation matrix,respectively.The renormalization group running of these operators can be studied separately from other operators of equal mass dimension at the leading order in power counting.We compute their anomalous dimensions at one loop for general d and find that they are enhanced quadratically in d due to combinatorics.We also make connections with classification of operators in terms of their holomorphic and anti-holomorphic weights.     

Night vision dense crowd counting based on mid-term fusion of thermal imaging features北大核心CSCD

为了提高人群计数模型对尺度和光噪声的鲁棒性,设计了一种多模态图像融合网络。提出了一种针对夜间人群统计模型,并设计了一个子网络Rgb-T-net,网络融合了热成像特征和可见光图像的特征,增强了网络对热成像和夜间人群特征的判断能力。模型采用自适应高斯核对密度图进行回归,在Rgb-T-CC数据集上完成了夜视训练和测试。经验证网络平均绝对误差为18.16,均方误差为32.14,目标检测召回率为97.65%,计数性能和检测表现优于当前最先进的双峰融合方法。实验结果表明,所提出的多模态特征融合网络能够解决夜视环境下的计数与检测问题,消融实验进一步证明了融合模型各部分参数的有效性。     

上海光源XAFS线站时间分辨X射线激发发光谱实验系统

介绍了上海光源XAFS线站（BL14W1）的时间分辨X射线激发发光光谱（TRXEOL）实验系统。该系统基于时间相关单光子计数法的原理设计,以同步辐射光源的脉冲特性及其良好的时间结构为基础,通过集成定时系统、光谱仪系统和核电子学系统,在国内同步辐射装置上首次实现了TRXEOL实验方法。定时系统提供同步触发电脉冲,用来标志X射线脉冲打到样品上的时刻,同步精度约6 ps,延时分辨率5 ps;光谱仪经光电探测器把样品发光信号转换成电脉冲,核电子学系统对定时电脉冲和发光电脉冲之间的时间差进行统计分析,可得到样品的发光衰减曲线,再结合光谱仪的扫描控制和数据获取系统,可得到样品的TRXEOL光谱。利用该实验系统可以测量发光样品的普通XEOL光谱、发光衰减曲线和TRXEOL光谱。用ZnO纳米线样品,进行了实验验证。实验得到的普通XEOL光谱能够明显区分该样品在390和500 nm处的两个发光中心;得到的发光衰减曲线能够区分小于2 ns的快发光过程和200 ns的慢发光过程;分别在0～1, 2～200和0～200 ns时间窗口内测量得到了ZnO纳米线样品的TRXEOL光谱,在这3个发光时间带内得到了对应的发光信息;ZnO纳米线样品发光衰减曲线快发光峰的半高宽约为0.5 ns,证明了TRXEOL系统的最小时间分辨率小于1 ns。该系统在国内同步辐射装置上提供了用于研究发光材料的TRXEOL实验方法,该方法与发光模式的XAFS方法相结合,可更深入的研究发光材料的发光行为。整个实验平台操作简便、工作稳定可靠,不仅为发光材料的研究提供了研究手段,还为进一步开展发光模式XAFS和TRXEOL成像等实验方法提供技术前提。     

Determination/estimation of an optimal replacement interval under minimal repair

In this paper the problem of estimation of an optimal replacement interval for a system which is minimally repaired at failures is studied. The problem is investigated both under a parametric and a nonparametric form of the failure intensity of the system. It is assumed that observational data from n systems are available. Some asymptotic results are shown. A graphical procedure for determining/estimating an optimal replacement interval is presented. The procedure is particularly valuable for sensitivity analyses, for example with respect to the costs involved.     

Application of a Laplace Transform Method to the Study of Binary Mixtures of Spherical and Rod-Like Particles for Low Intensity Levels.

A Laplace Transform (LT) method is used to improve the results obtained in a quasi-elastic scattering (QELS) experiment. This is designed to determine the characteristic parameters of a bimodal solution of spherical and rod-like macromolecules. The theoretical study and the experimental simulation are carried out for low light levels and the results show that the LT technique provides a real alternative to the second order correlation function, g⁽²⁾(τ), in QELS measurements for these particularly difficult experimental conditions.     

Internal radiocesium contamination of adults and children in Fukushima 7 to 20 months after the Fukushima NPP accident as measured by extensive whole-body-counter surveys

The Fukushima Dai-ichi NPP accident contaminated the soil of densely-populated regions in Fukushima Prefecture with radioactive cesium, which poses significant risks of internal and external exposure to the residents. If we apply the knowledge of post-Chernobyl accident studies, internal exposures in excess of a few mSv/y would be expected to be frequent in Fukushima.Extensive whole-body-counter surveys (n = 32,811) carried out at the Hirata Central Hospital between October, 2011 and November, 2012, however show that the internal exposure levels of residents are much lower than estimated. In particular, the first sampling-bias-free assessment of the internal exposure of children in the town of Miharu, Fukushima, shows that the ¹³⁷Cs body burdens of all children (n = 1,383, ages 6–15, covering 95% of children enrolled in town-operated schools) were below the detection limit of 300 Bq/body in the fall of 2012. These results are not conclusive for the prefecture as a whole, but are consistent with results obtained from other municipalities in the prefecture, and with prefectural data.     

Additive hazards regression with random effects for clustered failure times

Additive hazards model with random effects is proposed for modelling the correlated failure time data when focus is on comparing the failure times within clusters and on estimating the correlation between failure times from the same cluster, as well as the marginal regression parameters. Our model features that, when marginalized over the random effect variable, it still enjoys the structure of the additive hazards model. We develop the estimating equations for inferring the regression parameters. The proposed estimators are shown to be consistent and asymptotically normal under appropriate regularity conditions. Furthermore, the estimator of the baseline hazards function is proposed and its asymptotic properties are also established. We propose a class of diagnostic methods to assess the overall fitting adequacy of the additive hazards model with random effects. We conduct simulation studies to evaluate the finite sample behaviors of the proposed estimators in various scenarios. Analysis of the Diabetic Retinopathy Study is provided as an illustration for the proposed method.     

Elementary Andreev processes in a driven superconductor–normal metal contact

We investigate the full counting statistics of a voltage-driven normal metal(N)–superconductor(S) contact. In the low-bias regime below the superconducting gap, the NS contact can be mapped onto a purely normal contact, albeit with doubled voltage and counting fields. Hence in this regime the transport characteristics can be obtained by the corresponding substitution of the normal metal results. The elementary processes are single Andreev transfers and electron- and hole-like Andreev transfers. Considering Lorentzian voltage pulses we find an optimal quantization for half-integer Levitons.     

基于超短脉冲的癌细胞荧光光谱

研究用于癌症诊断与治疗的光敏剂血卟啉(hematoporphyrin derivative,HPD)的超快光动力学过程。采用超短脉冲激光光谱技术和皮秒时间相关单光子计数系统,测量经血卟啉培养的活体癌细胞与正常细胞的荧光光谱、荧光寿命特性及荧光峰值强度随时间的变化,观测到:癌细胞样品在645nm处具有特征发射光谱峰;癌细胞与正常细胞样品荧光寿命的快成分分别为150,300ps;癌细胞与正常细胞的荧光峰值强度经12h分别衰减10%和55%。对测量所得的荧光光谱曲线及时间分辨荧光衰减曲线分析,计算出:在癌细胞内部血卟啉浓度增大了约2个数量级;癌细胞与正常细胞的荧光寿命分别为824,1798ps;血卟啉在癌细胞与正常细胞样品中滞留时间分别为17,6d。测量结果确认了荧光光谱技术诊断与治疗癌症的可行性,并对发展超短脉冲激光光谱技术早期诊断与治疗癌症具有重要的指导意义和临床应用价值。