Construction and structure studies of DNA-bipyridine complexes as versatile scaffolds for site-specific incorporation of metal ions into DNA

The facile construction of metal–DNA complexes using ‘Click’ reactions is reported here. A series of 2′-propargyl-modified DNA oligonucleotides were initially synthesized as structure scaffolds and were then modified through ‘Click’ reaction to incorporate a bipyridine ligand equipped with an azido group. These metal chelating ligands can be placed in the DNA context in site-specific fashion to provide versatile templates for binding various metal ions, which are exchangeable using a simple EDTA washing-and-filtration step. The constructed metal–DNA complexes were found to be thermally stable. Their structures were explored by solving a crystal structure of a propargyl-modified DNA duplex and installing the bipyridine ligands by molecular modeling and simulation. These metal–DNA complexes could have wide applications as novel organometallic catalysts, artificial ribonucleases, and potential metal delivery systems.     

Rational Design of Hierarchical “Ceramic‐in‐Polymer” and “Polymer‐in‐Ceramic” Electrolytes for Dendrite‐Free Solid‐State Batteries

Solid polymer electrolytes as one of the promising solid‐state electrolytes have received extensive attention due to their excellent flexibility. However, the issues of lithium (Li) dendrite growth still hinder their practical applications in solid‐state batteries (SSBs). Herein, composite electrolytes from “ceramic‐in‐polymer” (CIP) to “polymer‐in‐ceramic” (PIC) with different sizes of garnet particles are investigated for their effectiveness in dendrite suppression. While the CIP electrolyte with 20 vol% 200 nm Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) particles (CIP‐200 nm) exhibits the highest ionic conductivity of 1.6 × 10^?4 S cm^?1 at 30 °C and excellent flexibility, the PIC electrolyte with 80 vol% 5 µm LLZTO (PIC‐5 µm) shows the highest tensile strength of 12.7 MPa. A sandwich‐type composite electrolyte (SCE) with hierarchical garnet particles (a PIC‐5 µm interlayer sandwiched between two CIP‐200 nm thin layers) is constructed to simultaneously achieve dendrite suppression and excellent interfacial contact with Li metal. The SCE enables highly stable Li plating/stripping cycling for over 400 h at 0.2 mA cm^?2 at 30 °C. The LiFePO₄/SCE/Li cells also demonstrate excellent cycle performance at room temperature. Fabricating sandwich‐type composite electrolytes with hierarchical filler designs can be an effective strategy to achieve dendrite‐free SSBs with high performance and high safety at room temperature.     

Recent advances in lactic acid production by microbial fermentation processes

Fermentative production of optically pure lactic acid has roused interest among researchers in recent years due to its high potential for applications in a wide range of fields. More specifically, the sharp increase in manufacturing of biodegradable polylactic acid (PLA) materials, green alternatives to petroleum-derived plastics, has significantly increased the global interest in lactic acid production. However, higher production costs have hindered the large-scale application of PLA because of the high price of lactic acid. Therefore, reduction of lactic acid production cost through utilization of inexpensive substrates and improvement of lactic acid production and productivity has become an important goal. Various methods have been employed for enhanced lactic acid production, including several bioprocess techniques facilitated by wild-type and/or engineered microbes. In this review, we will discuss lactic acid producers with relation to their fermentation characteristics and metabolism. Inexpensive fermentative substrates, such as dairy products, food and agro-industrial wastes, glycerol, and algal biomass alternatives to costly pure sugars and food crops are introduced. The operational modes and fermentation methods that have been recently reported to improve lactic acid production in terms of concentrations, yields, and productivities are summarized and compared. High cell density fermentation through immobilization and cell-recycling techniques are also addressed. Finally, advances in recovery processes and concluding remarks on the future outlook of lactic acid production are presented.     

获取复配农药最佳增效配方的一种简易方法

借鉴共毒因子法评价农药复配联合作用的思想,将参与复配的单剂引起25％死亡率的剂量定为零水平,利用二次回归通用旋转组合设计安排实验研究氯氰菊酯和喹硫磷复配对斜纹夜蛾（Spodoptera litura）2龄幼虫的增效作用,得出杀虫剂使用量与斜纹夜蛾幼虫死亡率机率值之间的关系,从共毒系数（CTC）的计算公式推导出共毒系数与杀虫混剂中两单剂使用浓度N1、N2之间的数学关系,CTC＝100／N1／α N2/b（α、b分别为氯氰菊酯和喹硫磷的LC50）,进而确定最优化问题的目标函数j=N1/α＋N2／b,利用国际统计分析软件SAS的NLP过程求最大共毒系数和最优配方,所得结论与共毒系数法一致。     

Luminescence characteristics of Na3Ca2(SO4)3F: Ce3+ fluoride material

A new Na₃Ca₂(SO₄)₃F: Ce³⁺ phosphor synthesized by a solid state diffusion method is reported. The photoluminescence study showed a single high intensity emission peak at 307 nm wavelength when excited by UV light of wavelength 278 nm. An unresolved peak of comparatively less intensity was also observed at 357 nm along with the main peak. The characteristic emission of dopant Ce in Na₃Ca₂(SO₄)₃F phosphor clearly indicated that it resides in the host lattice in trivalent form. The emission peak can be attributed to 5d → 4f transition of rare earth Ce³⁺. The prepared sample is also characterized for its thermoluminescence properties. The TL glow curve of prepared sample showed a single broad peak at 147°C. The trapping parameters are also evaluated by Chen's method. The values of trap depth (E) and frequency factor (s) were found to be 0.64 ± 0.002 eV and 1.43 × 10⁷ s^–1 respectively. The study of PL and TL along with evaluation of trapping parameters has been undertaken and discussed for the first time. Copyright © 2014 John Wiley & Sons, Ltd.     

Materials Metabolism Analysis of China's Highway Traffic System (HTS) for Promoting Circular Economy

With the rapid growth of highway mileage and vehicles, the Chinese highway traffic system (HTS) has become one of the great resource consumers. This article attempts to evaluate the material metabolism of China's HTS during 2001–2005 using the approach of material flow analysis (MFA) and to explore possible measures to promote circular economy throughout HTS. We measured a set of indicators to illustrate the whole material metabolism of China's HTS. The results indicated that the direct material input (DMI) of China's HTS increased from 1181.26 million tonnes (Mt) in 2001 to 1,874.57 Mt in 2005, and about 80% of DMI was accumulated in the system as infrastructure and vehicles. The domestic processed output (DPO) increased by 59.0% from 2001 to 2005. Carbon dioxide and solid waste accounted for 80.5% and 10.4% of DPO, respectively. The increase of resource consumption and pollutant emissions kept pace with the growth of transportation turnover. All these suggest that China's HTS still followed an extensive linear developing pattern with large resource consumption and heavy pollution emissions during the study period, which brought great challenges to the resources and the environment. Therefore, it's high time for China to implement a circular economy throughout the HTS by instituting resource and energy savings, by reducing emissions in the field of infrastructure construction and maintenance, by reducing vehicles’ energy and materials consumption, and by recycling waste materials.     

Embodied Resource Flows and Product Flows

We develop the absorbing Markov chain (AMC) for describing in detail the network of paths through an industrial system taken by an embodied resource from extraction through intermediate products and, finally, consumer products. We refer to this as a resource‐specific network. This work builds on a recent literature in industrial ecology that uses an AMC to quantify the number of times a resource passes through a recycling sector before ending up in a landfill. Our objective is to incorporate into that analysis an input‐output (IO) table so that the resource paths explicitly take account of the interdependence of sectors through their reliance on intermediate products. This feature makes it possible to track multiple resources simultaneously and consistently and to represent both resources and products in mixed units. Hypothetical scenarios about technological changes and changes in consumer demand are analyzed with an IO model, and model solutions generate the AMC database. A numerical example is provided. We identify the three most critical enhancements to the standard IO model that will be needed for analyzing material cycles: the incorporation of waste‐processing sectors, stock and flow relationships, and international trade. The idea is to implement an AMC after each modeling step for analyses, such as tracking a resource extracted in one region to landfills in other regions and evaluating ways to intensify secondary recovery at key junctures in between.     

Optimisation of a microwave-assisted method for extracting withaferin A from Withania somnifera Dunal. using central composite design

Introduction – Recently, there have been growing attention on the modification and optimisation of new extraction and quantification methods, caused by the lack of environmentally friendly methodologies for the extraction of phytochemicals from complex matrices. In the case of pharmaceutical compounds, not only the extraction procedure but also the analysis method should be efficient, precise, fast and easy. Objectives – The essential pharmaceutical characteristics and trace concentration of withanolides led us to modify and optimise the previously reported extraction and quantification procedure for withaferin A (WA) as a candidate for withanolides. Matrial and methods – The WA from the air‐dried aerial part of Withania somnifera Dunal. was extracted using a microwave‐assisted extraction (MAE) technique. Four variables affecting the extraction procedure were optimised using the central composite design approach. The method of high‐performance thin‐layer chromatography assay was validated and applied for the quantification of each experiment. Results – The optimum values of factors were: extraction time (150 s), extraction temperature (68°C) and 17 mL of methanol : water in the ratio 25 : 75 as extracting solvent. The solvent system consisted of ethyl acetate : toluene : formic acid : 2‐propanol (7.0 : 2.0 : 0.5 : 0.5, v/v/v/v), and densitometric scanning at 220 nm was applied for the analysis. The dynamic linear range, LOD, LOQ and recovery with the inter‐day, and intra‐day RSDs of the developed method indicated the validity of the method. Conclusion – A pressurised MAE method for extracting WA from the plant's aerial part was optimised using factorial‐based design. The net effect of time, temperature, solvent volume and its ratio suggests that the yield of WA increases until each factor reaches its optimum value, and decreases with further increase in temperature or solvent ratio. Copyright © 2010 John Wiley & Sons, Ltd.     

Single molecule effects of osteogenesis imperfecta mutations in tropocollagen protein domains

Osteogenesis imperfecta (OI) is a genetic disease characterized by fragile bones, skeletal deformities and, in severe cases, prenatal death that affects more than 1 in 10,000 individuals. Here we show by full atomistic simulation in explicit solvent that OI mutations have a significant influence on the mechanical properties of single tropocollagen molecules, and that the severity of different forms of OI is directly correlated with the reduction of the mechanical stiffness of individual tropocollagen molecules. The reduction of molecular stiffness provides insight into the molecular‐scale mechanisms of the disease. The analysis of the molecular mechanisms reveals that physical parameters of side‐chain volume and hydropathy index of the mutated residue control the loss of mechanical stiffness of individual tropocollagen molecules. We propose a model that enables us to predict the loss of stiffness based on these physical characteristics of mutations. This finding provides an atomistic‐level mechanistic understanding of the role of OI mutations in defining the properties of the basic protein constituents, which could eventually lead to new strategies for diagnosis and treatment the disease. The focus on material properties and their role in genetic diseases is an important, yet so far only little explored, aspect in studying the mechanisms that lead to pathological conditions. The consideration of how material properties change in diseases could lead to a new paradigm that may expand beyond the focus on biochemical readings alone and include a characterization of material properties in diagnosis and treatment, an effort referred to as materiomics.     

Extending effectiveness to efficiency: Comparing energy and environmental assessment methods for a wet cooling tower

Improving the environmental performance and energy efficiency of cooling towers requires systematic evaluation. However, methodological challenges emerge when applying typical environmental assessment methods to cooling towers. Hence, this paper compares the methods, analyzes their strengths and weaknesses, and proposes adaptions for evaluating cooling towers. As a case study, we applied five methods for assessing the wet cooling system of the high-performance data center in Stuttgart. These are material flow analysis (MFA), life cycle inventory, life cycle assessment (LCA), exergy analysis, and life cycle exergy analysis (LCEA). The comparison highlights that the LCA provides the most comprehensive environmental evaluation of cooling systems by considering several environmental impact dimensions. In the case of the wet cooling tower, however, electricity and water consumption cause more than 97% of the environmental impacts in all considered impact categories. Therefore, MFA containing energy flows suffices in many cases. Using exergy efficiency is controversially debated because exergy destruction is part of the technical principle applied in cooling towers and, therefore, difficult to interpret. The LCEA appears inappropriate because construction and disposal barely affect the exergy balance and are associated with transiting exergy. The method comparison demonstrates the need for further methodological development, such as dynamic extensions or the efficiency definition of cooling towers. The paper highlights that the methodological needs depend on the specific application.