Biologically Relevant Molecular Finite Automata

Bio-Molecular Computing (BMC) has been rapidly evolving as an independent field at the interface between computer science, mathematics, chemistry, and biology. Over the years, numerous architectures of autonomous molecular computing devices have been developed in the lab on the basis of opportunities offered by molecular biology techniques. This account focuses mainly on the realization of programmable DNA-based finite-state automata that can compute autonomously upon mixing all their components in solution.The main advantage of autonomous BMC devices over electronic computers arises from their ability to interact directly with biological systems and even with living organisms without any interface. Indeed, it has been demonstrated that appropriately designed computing machines can produce output signals in the form of a specific biological function via direct interaction with living cells. Additional topics are briefly included to point at interesting opportunities in the field and to describe some of the potential applications and extension of the basic concepts. These include logic evaluators and logic gates that operate in cells, applications in developmental biology, as well as chemical encoding and processing of alphanumeric information.     

Information gathering and processing with fluorescent molecules

Molecular information gathering and processing — a young field of applied chemistry — is undergoing good growth. The progress is occurring both in terms of conceptual development and in terms of the strengthening of older concepts with new examples. This review critically surveys these two broad avenues. We consider some cases where molecules emulate one of the building blocks of electronic logic gates. We then examine molecular emulation of various Boolean logic gates carrying one, two or three inputs. Some single-input gates are popular information gathering devices. Special systems, such as ‘lab-on-a-molecule’ and molecular keypad locks, also receive attention. A situation deviating from the Boolean blueprint is also discussed. Some pointers are offered for maintaining the upward curve of the field.     

A DNA network as an information processing system

Biomolecular systems that can process information are sought for computational applications, because of their potential for parallelism and miniaturization and because their biocompatibility also makes them suitable for future biomedical applications. DNA has been used to design machines, motors, finite automata, logic gates, reaction networks and logic programs, amongst many other structures and dynamic behaviours. Here we design and program a synthetic DNA network to implement computational paradigms abstracted from cellular regulatory networks. These show information processing properties that are desirable in artificial, engineered molecular systems, including robustness of the output in relation to different sources of variation. We show the results of numerical simulations of the dynamic behaviour of the network and preliminary experimental analysis of its main components.     

Molecular Electronics: Beyond the Limits of Conventional Electronics

Abstract

Future technologies in information science will reiy on structures with decreasing size and on systems with increasing complexity. The physical and technological limits of semiconductor nanostructures point to the use of molecules and atoms in information science. In particular, organic molecules are very attractive because they can be engineered with very large complexity, and their electronic and optical properties can be controlled technologically. Already today many fundamental functions and devices relevant to information technology can be realized with systems of organic molecules: Switchable molecules lead to the development of memories with large capacity, transmission of information is possible through “molecular wires”, and the flow of information can be interrupted by “switching molecules”. Together with other logical elements this opens the possibility to develop future systems in information technology. However, this requires suitable supramolecular arrangements for complex interconnections of logical elements and memory molecules, as well as a suitable electrical or optical periphery.     

SYNTHESIS AND APPLICATIONS OF NANOMATERIALS IN MICROELECTRONICS

The technology boom in microelectronics and telecommunication industry has presented a unique opportunity for nanomaterials. Nanomaterials enable the creation of unique devices, components and systems through the control of matter on a near molecular level. These new devices, components and systems will exhibit novel physical, chemical, mechanical, electrical, optical and biological properties. The synthesis processes of nanomaterials are reviewed and the applications of nanomatorials in microelectronics are discussed in this paper.     

Nanoscale Digital Devices Based on the Photoelectrochemical Photocurrent Switching Effect: Preparation,Properties and Applications

New materials and new phenomena which can be used for information processing always inspire great enthusiasm. On the other hand, silicon is still the main workhorse of modern electronics. Production of bulk quantities of ultrapure silicon is relatively cheap and the processing technologies are extremely sophisticated. Introduction of new materials and phenomena, on the other hand, requires an enormous amount of hard experimental and theoretical work. The photoelectrochemical photocurrent switching effect (PEPS) is one of the processes that, in principle, can evolve into new information processing technology. This review presents the effect itself, along with preparation of appropriate semiconducting materials, physical principles of semiconductor–molecule interactions, and finally some prototypical constructions of logic devices based on the PEPS effect.     

Surface-confined assemblies and polymers for molecular logic

Stimuli responsive materials are capable of mimicking the operation characteristics of logic gates such as AND, OR, NOR, and even flip-flops. Since the development of molecular sensors and the introduction of the first AND gate in solution by de Silva in 1993, Molecular (Boolean) Logic and Computing (MBLC) has become increasingly popular. In this Account, we present recent research activities that focus on MBLC with electrochromic polymers and metal polypyridyl complexes on a solid support. Metal polypyridyl complexes act as useful sensors to a variety of analytes in solution (i.e., H(2)O, Fe(2+/3+), Cr(6+), NO(+)) and in the gas phase (NO(x) in air). This information transfer, whether the analyte is present, is based on the reversible redox chemistry of the metal complexes, which are stable up to 200 °C in air. The concurrent changes in the optical properties are nondestructive and fast. In such a setup, the input is directly related to the output and, therefore, can be represented by one-input logic gates. These input-output relationships are extendable for mimicking the diverse functions of essential molecular logic gates and circuits within a set of Boolean algebraic operations. Such a molecular approach towards Boolean logic has yielded a series of proof-of-concept devices: logic gates, multiplexers, half-adders, and flip-flop logic circuits. MBLC is a versatile and, potentially, a parallel approach to silicon circuits: assemblies of these molecular gates can perform a wide variety of logic tasks through reconfiguration of their inputs. Although these developments do not require a semiconductor blueprint, similar guidelines such as signal propagation, gate-to-gate communication, propagation delay, and combinatorial and sequential logic will play a critical role in allowing this field to mature. For instance, gate-to-gate communication by chemical wiring of the gates with metal ions as electron carriers results in the integration of stand-alone systems: the output of one gate is used as the input for another gate. Using the same setup, we were able to display both combinatorial and sequential logic. We have demonstrated MBLC by coupling electrochemical inputs with optical readout, which resulted in various logic architectures built on a redox-active, functionalized surface. Electrochemically operated sequential logic systems such as flip-flops, multivalued logic, and multistate memory could enhance computational power without increasing spatial requirements. Applying multivalued digits in data storage could exponentially increase memory capacity. Furthermore, we evaluate the pros and cons of MBLC and identify targets for future research in this Account.     

硅基电子气去除甲基氯硅烷的分子动力学模拟

光纤通信技术具有通信容量大、传输损耗低、保密性能好等优点,是一种极有前途的多路通信手段。相关技术中利用硅基电子气SiCl₄经化学气相沉积法制备光纤预制棒,但是SiCl₄中的含金属杂质和含氢杂质因对光子产生很大的振动吸收而增加光纤传输中光的吸收损耗。光纤用SiCl₄对纯度的要求极高,其中含氢杂质甲基氯硅烷的含量需降低到5mg/kg或者更低。通过光氯化法结合精馏工艺提纯SiCl₄是目前为止制备光纤用高纯SiCl₄最合适的方法。本文针对光氯化法去除甲基氯硅烷杂质的工艺过程进行分子层面的反应分子动力学模拟研究,重点比较分析了Cl₂与Cl自由基及反应温度对甲基氯硅烷的去除效果,并探究了不同的模拟体系中形成的主要的中间产物及其主要的转化路径,为光氯化除杂反应提供了基础的化学反应机理及工艺的改进方向。模拟结果表明,在反应体系中引入Cl自由基后对甲基氯硅烷的去除效率能够达到相同模拟条件下Cl₂的2倍;体系的反应温度与甲基氯硅烷的去除效率之间的相互关系并不是单调变化的,存在最佳反应温度（373K）使甲基氯硅烷的去除效率达到最大;甲基氯硅烷分子中的C—H键及C—Si键因具有较大的键能而难断裂,只有当体系内反应温度升高到一定值后（423K）才可观察到C—H键的断裂,只有在体系内引入活泼的Cl自由基后才可观察到C—Si键的断裂。     

Computer simulation of reactive extrusion processes for free radical polymerization

The reactive extrusion for polymerization is an integrated polymer processing technology. A new semi‐implicit iterative algorithm was proposed to deal with the complicated relationships among the chemical reaction, the macromolecular structure and the chemorheological property. Then the numerical computation expressions of the average molecular weight, the monomer conversion, and the initiator concentration were deduced, and the computer simulation of the reactive extrusion process for free radical polymerization was carried out, on basis of which reactive processing conditions can be optimized. POLYM. ENG. SCI., 47:667–674, 2007. © 2007 Society of Plastics Engineers.     

Molecular and submolecular scale effects of comb‐copolymers on tri‐calcium silicate reactivity: Toward molecular design

The impact of organic compounds on the processing and reactivity of inorganic materials has been a source of inspiration for materials scientists for decades and continues to trigger novel and innovative applications in a broad range of disciplines. However, molecular design of such compounds to reach targeted properties remains challenging, particularly for reactive and multicomponent systems. This outstanding challenge is met here by combining a model cement, hosting different coupled reactions of dissolution, nucleation and growth, together with comb‐copolymers that offer large and well‐controlled variations of their molecular architecture. We show that silicate reactivity is affected by a combination of molecular and submolecular scale effects of these polymers. The first can be described by scaling laws from polymer physics, whereas the second involves specific chemical interactions. In particular, the ability of these polymers to hinder dissolution appears to be crucial, something for which strong experimental evidence is provided.     

RTM专用混合型树脂体系研究——反应特性与工艺特性研究

本文采用乙烯基酯树脂和环氧树脂体系共混改性的方法。研究和开发具有良好工艺性、耐热性和力学性能的低成本ＲＴＭ用树脂体系。研究表明，乙烯基酯树脂和环氧树脂体系具有良好的共混特性。ＤＳＣ及粘度分析研究表明，混合型树脂体系中的乙烯基酯组份分散了环氧树脂的反应放热，有效降低了７１１环氧树脂的反应速度和改善了树脂的工艺特性。使混合型树脂具有较好的ＲＴＭ工艺低粘度平台工艺性能。所研究的混合型树脂体系可用于ＲＴＭ     

Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors

Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing. In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol-gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed "solid-state probe" technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self-powered and intelligent aptasensors for the logic detection. We have developed biocomputing keypad lock security systems which can be also used for intelligent medical diagnostics. BECI engineering provides a simple but effective approach toward the design and fabrication of EC-biosensors, BFCs, and self-powered logic biosensors, which will make essential contributions in the development of creative and practical bioelectronic devices. The exploration of novel interface engineering applications and the creation of new fabrication concepts or methods merit further attention.     

强化化工专业本科生计算机应用能力培养

以武汉科技大学化学工程与技术学院化学工程与工艺专业为例,介绍了优化培养计划、在专业理论教学中融入计算机应用和在实践教学强中融入计算机应用等强化化工专业本科生计算机应用能力培养的具体措施。指出化工专业本科生计算机应用能力的培养是一项系统工程,光靠低年级开设的那几门计算机课程是不够的,在高年级阶段还要继续强化计算机应用能力的培养。     

Molecular junctions: from tunneling to function

Thanks to the development of appropriate experimental techniques, molecular devices and their electrical transport properties have recently been the focus of a major research effort. This brief review describes how individual molecules can be contacted with metallic electrodes to form molecular junctions and addresses their basic formation mechanisms. An extension to molecular junctions networks is also discussed. Functionality could be demonstrated in such systems, and examples where conductance modulation using light or chemical stimuli was achieved will be presented.     

Quasi-classical modeling of molecular quantum-dot cellular automata multidriver gates

ABSTRACT: Molecular quantum-dot cellular automata (mQCA) has received considerable attention in nanoscience. Unlike the current-based molecular switches where the digital data is represented by the on/off states of the switches, in mQCA devices, binary information is encoded in charge configuration within molecular redox centers. The mQCA paradigm allows high device density and ultra-low power consumption. Digital mQCA gates are the building blocks of circuits in this paradigm. Design and analysis of these gates require quantum chemical calculations, which are demanding in computer time and memory. Therefore, developing simple models to probe mQCA gates is of paramount importance. We derive a semi-classical model to study the steady-state output polarization of mQCA multidriver gates, directly from the two-state approximation in electron transfer theory. The accuracy and validity of this model are analyzed using full quantum chemistry calculations. A complete set of logic gates, including inverters and minority voters, are implemented to provide an appropriate test bench in the two-dot mQCA regime. We also briefly discuss how the QCADesigner tool could find its application in simulation of mQCA devices.     

计算机机房用防静电聚氯乙烯型材研制

研究了计算机机房用聚氯乙烯防静电型材的生产工艺，探讨了不同炭黑品种、各种添加剂、工艺过程及加工条件对型材性能的影响。通过选择配方与加工条件，获得了综合性能良好的防静电型材。将其用于机房活动地板，导静电能力可达到国家标准A级水平。     

AD干式复合胶粘剂的研制

本文研究了AD干式复合胶粘剂(干复胶)的性能和单体组成,丙烯酸酯共聚物的合成工艺以及成份之间的相互关系。结果表明,AD干复胶的性能达到和某些性能优于常用聚氨酯干复胶的水平,且成木降低了20～30%。     

化学品信息管理与环境保护

随着人类社会的发展,人们对物质的种类需求越来越多、数量越来越大。由于已有的天然资源已不能满足这样的需求,必须使用大量的人造制品来弥补这样的空缺,而人造制品中的绝大部分是化学类物质。这些化学物质在极大地满足了人类社会需求的同时,也给人类赖以生存的环境造成了一定的污染。为此,必须应用有效的方法管理化学品,以保证人类能够安全有效使用化学品的同时确保生活环境的安全。随着计算机技术的发展,计算机信息管理系统几乎承担了所有领域的信息管理工作。目前,在化学领域,用于化学信息管理的系统有:SciFinder、ISIS/Base、ELN和CISOC-ChIMS等。化学品信息的有效管理,将对环境保护起到积极的作用。     

A thermodynamic approach to the synthesis of heat integration systems in chemical processes

Starting with no heat integration, from initial structure for a chemical processing system, a series of modified systems with improved heat utilization can be evolutionally developed by a computer aided method, on the thermodynamic available energy concept. An illustrative example shows that processing systems with high degree of efficient energy utilization have been generated.     

Boolean logic gates that use enzymes as input signals

Biochemical systems that demonstrate the Boolean logic operations AND, OR, XOR, and InhibA were developed by using soluble compounds, which represent the chemical "devices", and the enzymes glucose oxidase (GOx), glucose dehydrogenase (GDH), alcohol dehydrogenase (AlcDH), and microperoxidase-11 (MP-11), which operated as the input signals that activated the logic gates. The enzymes were used as soluble materials and as immobilized biocatalysts. The studied systems are proposed to be a step towards the construction of "smart" signal-responsive materials with built-in Boolean logic.