Living Cells Directly Growing on a DNA/Mn3(PO4)2‐Immobilized and Vertically Aligned CNT Array as a Free‐Standing Hybrid Film for Highly Sensitive In Situ Detection of Released Superoxide Anions

It is important to detect reactive oxygen species (ROS) in situ for investigation of various critical biological processes, and this is however very challenging because of the limited sensitivity or/and selectivity of existing methods that are mainly based on sensing ROS released by cells with short lifetimes and low concentrations in a culture medium. Here, a new approach is reported to directly grow living cells on DNA/Mn₃(PO₄)₂‐immobilized and vertically aligned carbon nanotube (VACNT) array nanostructure as a smart free‐standing hybrid film, of which the DNA/Mn₃(PO₄)₂ and VACNT provide high electroactivity and excellent electron transport, respectively, while the directly grown cell on the nanostructure offers short diffusion distance to reaction sites, thus constructing a highly sensitive in situ method for detection of cancer‐cell‐released ROS under drug stimulations. Compared to the measured ROS released by cells in a culture medium, the detection sensitivity with this constructed hybrid film increases by more than six times, which implies that ROS molecules (superoxide anions) secreted from living cells are immediately captured by this smart structure without diffusion process or with extremely short diffusion distance. This design considerably reduces the time from release to detection of the target molecules, minimizing the potential molecular decay due to the short lifetime or high reactivity.     

地下咸水阴离子协同作用对316L不锈钢耐蚀性能的影响

滨海地区地下咸水对地源热泵换热系统中不锈钢材料的腐蚀十分严重.采用动电位极化扫描和电化学阻抗谱等方法研究了模拟咸水中不同阴离子协同作用下316L不锈钢的腐蚀行为.结果表明:随着Cl-浓度的增加,316L不锈钢耐蚀性降低.SO42-与Cl-协同作用时,高浓度的SO42-抑制了Cl-对316L不锈钢表面膜的破坏,增强其耐蚀性,低浓度的SO42-则降低其耐蚀性;而HCO3-与Cl-的协同作用对316L不锈钢耐蚀性影响的规律与之相反.当这3种阴离子共存时,其协同作用加速了316L不锈钢的腐蚀.这为不同地下水环境条件下地源热泵系统的选材提供了参考.     

土壤中阴离子对碳钢腐蚀的影响

用弱极化曲线技术和交流阻抗法研究了土壤中Cl-,SO42-,CO32-,NO3-对碳钢腐蚀的影响。结果表明:阴离子对碳钢腐蚀的影响比较显著。当土壤中分别添加Cl-,CO32-,NO3-时,随着阴离子质量浓度的增加,碳钢的腐蚀速率增大,在某一离子质量浓度时,腐蚀速率达到最大,然后腐蚀速率随着离子质量浓度的增加而减小。在有SO42-的土壤中随着SO42-质量浓度的增大,土壤中碳钢的腐蚀速率增大。在四种阴离子土壤中,阻抗谱均为单容抗弧,且大多在低频区出现扩散弧。     

低压离子色谱分析牙膏中常见无机阴离子

本论文利用低压离子色谱法测定常见的八种牙膏产品的含氟量及其他阴离子含量，并测定了该法的精密度、线性范围及回收率。实验证明用低压离子色谱法测定，精密度高、变异系数＜５％，峰高与浓度呈良好的线性关系，相关系数在０．９９６～０．９９８之间。     

Application of modern reliability database techniques to military system data

This paper focuses on analysis techniques of modern reliability databases, with an application to military system data. The analysis of military system data base consists of the following steps: clean the data and perform operation on it in order to obtain good estimators; present simple plots of data; analyze the data with statistical and probabilistic methods. Each step is dealt with separately and the main results are presented.Competing risks theory is advocated as the mathematical support for the analysis. The general framework of competing risks theory is presented together with simple independent and dependent competing risks models available in literature. These models are used to identify the reliability and maintenance indicators required by the operating personnel. Model selection is based on graphical interpretation of plotted data.     

Score tests for independence in parametric competing risks models

A popular model for competing risks postulates the existence of a latent unobserved failure time for each risk. Assuming that these underlying failure times are independent is attractive since it allows standard statistical tools for right-censored lifetime data to be used in the analysis. This paper proposes simple independence score tests for the validity of this assumption when parametric regression models are used to model the individual risks. The score tests are derived for the alternatives that specify that copulas are responsible for a possible dependency between competing risks. The test statistics are functions of the Cox and Snell residuals. A variance estimator is derived by writing the score function and the Fisher information matrix for the marginal models as stochastic integrals. A simulation study and a numerical example illustrate the methodology proposed in this paper.      

Organizational culture and willingness to share knowledge: A competing values perspective in Australian context

A considerable amount of research has confirmed the relationship between organizational culture and knowledge sharing behaviours. However, less research has been conducted on the impact of project sub-cultures in relation to the sharing of knowledge between projects, particularly in project based organizations (PBOs). The unique structures and contexts characterized by PBOs indicate the need to investigate further the impact of cultures present within PBOs and their effect on knowledge sharing. We report on a rich case study of four large Australian-based PBOs whereby the cultural values of these large organizations were seen to impact significantly on whether project teams were more or less likely to improve inter-project knowledge sharing. Furthermore, this research demonstrates the utility of using Cameron and Quinn's (2005) Competing Values Framework to evaluate culture in the context of PBOs.     

Decision and coordination in a competing retail channel involving a third-party logistics provider

This paper investigates decision and coordination in a supply-chain-wide system consisting of a manufacturer, a third-party logistics (3PL) provider, and two competing retailers. The product distribution functions may be implemented by the 3PL provider or the two retailers who face a decision problem that whether the 3PL provider should be introduced. The advantage of introducing the 3PL provider lies in his/her lower logistics cost. The drawback lies in the 3PL provider’s profit margin which leads to classic double marginalization. A new insight provided by this paper is that whether or not introducing the 3PL provider depends on the balance of these two effects. This paper reveals the conditions of the balance and explores the effect of retail competition on this balance. Furthermore, we discuss the dominant retailer model where one retailer is a price leader, and the other is a price follower. Whether the 3PL provider should be introduced under the dominant retailer model is also analyzed. Finally, three contracts: a spanning revenue-sharing contract, a quantity discount contract and a two-part tariffs contract are devised to effectively coordinate the decentralized system involving the 3PL provider.     

Examination of the best,analogous, competing terms to describe value in construction projects

Value is a crucial construct in project delivery. Yet, it is also a complex construct, with varied meanings. This study uses triangulated, empirical methods to examine competing terms used to imply value in the literature (focusing on construction projects). Deeper meaning is also provided on the subject from both the manifest and latent perspectives.     

Models involving two inverse Weibull distributions

In this paper, we look at three models (mixture, competing risk and multiplicative) involving two inverse Weibull distributions. We study the shapes of the density and failure-rate functions and discuss graphical methods to determine if a given data set can be modelled by one of these models.