Use of Fractional Factorial Designs in Antiviral Drug Studies

Experimental design and analysis is an effective and commonly used tool in scientific investigations and industrial applications. Many successful applications have been reported in engineering domains, such as chemical engineering, electrical engineering, and mechanical engineering. However, few cases have been reported in biological research, particularly in virology study. Antiviral drug combinations are increasingly used to reduce possible drug‐resistant viral mutant and reduce cytotoxicity. Drug combinations have often been reported to have higher efficacy and lower individual drug dosage. However, the combined antiviral drug effect is generally hard to assess. One important reason is due to the complex interactions between biological systems and drug molecules. We report a study using fractional factorial designs to investigate a biological system with Herpes simplex virus type 1 and five antiviral drugs. The experiment uses a novel composite design that consists of a 16‐run fractional factorial design and an 18‐run orthogonal array. The results indicate that two chemical drugs, Ribavirin and Acyclovir, are more effective than three Interferon drugs. Furthermore, significant interactions exist within the Interferon drug group and within the Ribavirin‐Acyclovir chemical drug group, but the interactions between the Interferon group and the chemical group are not significant. These observations have major implications in the understanding of antiviral drug mechanism towards better design of combinatorial antiviral drug therapy. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of a Rapid Prototyping System using Response Surface Methodology

This case study presents an investigation of the relationships between eight process operating variables (factors) and five part performance measures (responses) in a rapid prototyping system. The use of fractional factorial, single‐factor foldover, and central composite designs is demonstrated. Polynomial regression models are constructed for each response, followed by a desirability function model. Canonical and ridge analyses are used to identify a group of factor settings that simultaneously produce improved performance for all responses. Copyright © 2006 John Wiley & Sons, Ltd.     

A note on the Bayesian analysis of experiments with correlated multiple responses using a matrix‐logarithmic covariance model

In the literature, analysis of multiple responses from experiments with replicates has modeled the covariance matrix directly as linear models of the transformed variances and correlations, ie, covariance modeling. This article considers models based on the matrix‐logarithm of the covariance matrix. This so‐called log‐covariance modeling is illustrated with data from actual experiments and compared with the traditional covariance modeling.     

Cuscore Statistics to Monitor a Non‐stationary System

We investigate the monitoring of a process subject to minimum mean‐squared error feedback control using cumulative score (Cuscore) charts. Specifically, we design Cuscore statistics to discover spike, step, bump, and ramp signals hidden in non‐stationary disturbance for feedback‐controlled processes. We develop the adjustment and monitoring policies for combinations of process dynamics, disturbance, and signal that are practical in industry. We also address issues of detection probabilities and distributions using simulation. A manufacturing case study is used to illustrate the utility of the Cuscore approach. Copyright © 2006 John Wiley & Sons, Ltd.     

Visualizing the Growth and Dynamics of Liquid‐Ordered Domains During Lipid Bilayer Folding in a Microfluidic Chip

A microfluidic platform enabling optical monitoring of bilayer lipid membrane formation by a new monolayer folding process is described. The thermoplastic chips integrate dried lipid films that are rehydrated by microfluidic perfusion, which enables delivery of lipid‐laden air bubbles across a membrane‐supporting aperture. As in traditional Montal–Mueller bilayer formation, lipid monolayers are delivered independently to each side of the aperture, thereby allowing asymmetric lipid composition in the resulting bilayer to be achieved. Confocal microscopy is used to image the monolayer folding process, and reveals the growth and dynamics of asymmetric liquid‐ordered domains during bilayer stabilization.     

SMART Design of a Bulk‐Capped Supramolecular Segment for the Assembly into Organic Interdigital Lipid Bilayer‐Like (ILB) Nanosheets

Rational molecular design for the organic nanocrystal morphology still remains a challenge due to the structural diversity and complicated weak intermolecular interactions. In this work, a typical attractor–repulsor molecule N,N‐diphenyl‐4‐(9‐phenyl‐fluoren‐9‐yl) phenylamine (TPA‐PF) is designed to explore a general assembly strategy for 2D nanocrystals. Via an interdigital lipid bilayer‐like (ILB) molecular packing mode, large‐sized lamellar 2D nanosheets are obtained with a length:width:thickness ratio as ≈2500:1000:1. The d‐spacing of the largest (001) plane is 1.32 nm, which equals to the thickness of a single interdigital stacking layer. The synergetic effect of the attractive supramolecular segment (TPA) and the repulsive bulky group (PF) is supposed to be the critical factor for the ILB packing that leads to the 2D structures. The attractor–repulsor molecule design is expected to be an effective strategy for the growth of 2D nanocrystals based on small organic molecules.     

Exploring the Use of Design of Experiments in Industrial Processes Operating Under Closed‐Loop Control

Industrial manufacturing processes often operate under closed‐loop control, where automation aims to keep important process variables at their set‐points. In process industries such as pulp, paper, chemical and steel plants, it is often hard to find production processes operating in open loop. Instead, closed‐loop control systems will actively attempt to minimize the impact of process disturbances. However, we argue that an implicit assumption in most experimental investigations is that the studied system is open loop, allowing the experimental factors to freely affect the important system responses. This scenario is typically not found in process industries. The purpose of this article is therefore to explore issues of experimental design and analysis in processes operating under closed‐loop control and to illustrate how Design of Experiments can help in improving and optimizing such processes. The Tennessee Eastman challenge process simulator is used as a test‐bed to highlight two experimental scenarios. The first scenario explores the impact of experimental factors that may be considered as disturbances in the closed‐loop system. The second scenario exemplifies a screening design using the set‐points of controllers as experimental factors. We provide examples of how to analyze the two scenarios. © 2017 The Authors Quality and Reliability Engineering International Published by John Wiley & Sons Ltd     

Liposome Destabilization by a 2,7‐Diazapyrenium Derivative Through Formation of Transient Pores in the Lipid Bilayer

The effect of the luminescent heteroaromatic electron acceptor N,N′‐dimethyl‐2,7‐diazapyrenium dichloride (DM‐DAP²⁺) on the stability of 1‐palmitoyl‐2‐oleoylphosphatydilcholine (POPC) liposomes is determined on the basis of the rate of release of different fluorescent probes entrapped within the liposome. The experiments show that DM‐DAP²⁺ exerts a substantial destabilizing action on the liposomal bilayer, particularly at low concentrations. Molecular dynamics simulations suggest that the activity of DM‐DAP²⁺ is related to its tendency to surround itself with water molecules, conceivably favoring the formation of transient pores across the bilayer.     

Biomimetic Engineering of a Scavenger‐Free Nitric Oxide‐Generating/Delivering System to Enhance Radiation Therapy

Nitric oxide (NO) is a potent tumor‐cell radiosensitizer but it can be readily scavenged by hemoglobin (Hb) in vivo. A biomimetic incubator that can generate and deliver NO in a scavenger (Hb)‐free environment to enhance its radiosensitizing effect to maximize its efficacy in radiotherapy is proposed. This NO incubator comprises a poly(lactic‐co‐glycolic acid) (PLGA) hollow microsphere (HM) that contains an NO donor (NONOate) and a surfactant molecule (sodium caprate, SC) in its aqueous core. In acidic tumorous environments, the PLGA shell of the HM allows the penetration of protons from the outside, activating the hydrolytic cleavage of NONOate, spontaneously generating NO bubbles, which are immediately trapped/stabilized by SC. The SC‐stabilized NO bubbles in the HM are then squeezed through the spaces of its PLGA matrices by the elevated internal pressure. Upon leaving the HM, the entrapped NO molecules may passively diffuse through their SC‐stabilized/protected layer gradually to the tumor site, having a long‐lasting radiosensitizing effect and inhibiting tumor growth. The entire process of NO generation and delivery is conducted in a scavenger (Hb)‐free environment, mimicking the development of young ovoviviparous fish inside their mothers' bodies in the absence of predators before birth.     

A sensitivity analysis of an integrated model for joint determination of economic design of $\overline{x}$‐control charts,economic production quantity and production run length for a deteriorating production system

This study presents an integrated model for the joint economic design of ‐control charts and maintenance schedules and, simultaneously, determines the economic production quantity and production run length for a deteriorating production system. The operating state of the production process is classified as either in control or out of control. In the latter state, the process produces some defective items. An ‐control chart is used to monitor the process mean. Both uniform and non‐uniform inspection schemes are adopted. Inspection and maintenance are performed simultaneously. Replacement cost is assumed to be very high. The process failure mechanism is assumed to follow a general probability distribution with an increasing failure rate. The concept of a truncated production cycle is introduced. The production cycle begins when a new component is installed and ends with a repair after the detection of a failure or after a specified number of inspection intervals, , whichever occurs first. The effects of preventive maintenance on quality control are discussed. Numerical examples are provided to evaluate the performance of the model. Sensitivity analyses are conducted to study the effects of various model parameters. Copyright © 2002 John Wiley & Sons, Ltd.     

Fast Batch Production of High‐Quality Graphene Films in a Sealed Thermal Molecular Movement System

Chemical vapor deposition (CVD) growth of high‐quality graphene has emerged as the most promising technique in terms of its integrated manufacturing. However, there lacks a controllable growth method for producing high‐quality and a large‐quantity graphene films, simultaneously, at a fast growth rate, regardless of roll‐to‐roll (R2R) or batch‐to‐batch (B2B) methods. Here, a stationary‐atmospheric‐pressure CVD (SAPCVD) system based on thermal molecular movement, which enables fast B2B growth of continuous and uniform graphene films on tens of stacked Cu(111) foils, with a growth rate of 1.5 µ m s^?1, is demonstrated. The monolayer graphene of batch production is found to nucleate from arrays of well‐aligned domains, and the films possess few defects and exhibit high carrier mobility up to 6944 cm² V^?1 s^?1 at room temperature. The results indicate that the SAPCVD system combined with single‐domain Cu(111) substrates makes it possible to realize fast batch‐growth of high‐quality graphene films, which opens up enormous opportunities to use this unique 2D material for industrial device applications.     

Modulation of Electron Tunneling in a Nanoparticle Array by Sound Waves: An Avenue to High‐Speed,High‐Sensitivity Sensors

Using an electrostatic self‐assembly process, metal nanoparticles are deposited on polyelectrolyte fibers such that the interparticle distance between the nanoparticles is comparable to the polyelectrolyte's molecular width. By modulating the dielectric properties of the interparticle polymer layer, a highly sensitive, reversible humidity sensor with an ultrafast response time of ≈3 ms is demonstrated. The higher sensitivity at low humidity shows a conductivity increase by over two orders of magnitude in response to a change in relative humidity from 21 to 1%.     

R417a在热泵热水系统中替代R22的实验研究

在热泵热水系统中,对新混合工质R417a进行了理论制冷循环分析和灌注式替代R22的循环性能对比试验研究,结果表明混合工质R417a的制热量稍低于R22,但性能系数COP、压缩机排气温度和功耗等循环性能指标均优于R22,实验过程中R417a工质性能稳定,运行正常,不需更换润滑油。     

Optimization of Degree of Conformance in Multiresponse–Multistage Systems with a Simulation‐based Metaheuristic

In today's manufacturing and service systems, entities are progressed across the several stages of operations wherein one or more quality characteristic may be formed. The quality of final system outputs depends on the quality of intermediate characteristics as well as design parameters in each stage. This paper presents a new mathematical program to simultaneously optimize multiple quality characteristics in multiple stage systems. Multivariate form response surface methodology is applied with iterative seemingly unrelated regression as the estimation method to extract the relationships between the outputs and inputs in each stage. Because the intermediate response variables may act as covariates in the next stages, the probabilistic patterns of the response surfaces are considered by association with the quality of the previous stages. The objective function in the proposed model is the acceptance probability of the outputs based on predefined specification limits. A combination of Monte Carlo simulation and the genetic algorithm is also proposed to solve the final stochastic optimization model. At the end, the applicability of the proposed approach is illustrated by a numerical example. Copyright © 2014 John Wiley & Sons, Ltd.     

超高层建筑空调二次泵水系统运行分析

本文主要阐述了超高层建筑空调二次泵水系统的原理、盈亏管的设置及系统的运行控制策略,并给出了实际工程中超高层建筑空调二次泵水系统遇到的常见问题及解决方式,旨在为空调二次泵水系统设计提供参考。     

汽轮发电机组轴系扭振冲击和共振响应的主动控制

在多级阶梯轴系扭振弹性波解析分析的基础上 ,建立了一般转子轴系扭振主动控制的理论模型 ,提出了一种适合工程应用的转子轴系扭振主动控制方法 ,并以总扭振能最小为控制目标 ,对一台 30 0 MW汽轮发电机组轴系在多种激励下的扭振响应及其主动控制特性进行了计算机模拟 ,还利用扭振模拟实验台对轴系出现共振时的扭振稳态响应及其主动减振效果进行了考核     

Improvements in Spatial Ability as a Result of Targeted Training and Computer‐Aided Design Software Use: Analyses of Object Geometries and Rotation Types

Spatial ability, which affects retention and achievement in engineering and science disciplines, has been shown to improve through training and simply from enrollment in a Computer‐Aided Design (CAD) course. However, detailed analyses of the specific object geometries and rotation types that cause difficulty for students on standardized spatial ability tests or which ones improve based on training has not been performed. This information may assist in determining the optimal training methods to improve the spatial ability skills of students and thus provide the most significant benefits for the training time committed. In this paper, scores from a standardized spatial ability test, which was administered before and after training and/or enrollment in a CAD course, are compared. The results show that the targeted training produced a significant improvement in the spatial ability test scores of students and that these improvements occur across all object geometries and rotation types.