Exploring the evolution and epidemiology of European CC1-MRSA-IV: tracking a multidrug-resistant community-associated meticillin-resistant Staphylococcus aureus clone

This study investigated the evolution and epidemiology of the community-associated and multidrug-resistant Staphylococcus aureus clone European CC1-MRSA-IV. Whole-genome sequences were obtained for 194 European CC1-MRSA-IV isolates (189 of human and 5 of animal origin) from 12 countries, and 10 meticillin-susceptible precursors (from North-Eastern Romania; all of human origin) of the clone. Phylogenetic analysis was performed using a maximum-likelihood approach, a time-measured phylogeny was reconstructed using Bayesian analysis, and in silico microarray genotyping was performed to identify resistance, virulence-associated and SCCmec (staphylococcal cassette chromosome mec) genes. Isolates were typically sequence type 1 (190/204) and spa type t127 (183/204). Bayesian analysis indicated that European CC1-MRSA-IV emerged in approximately 1995 before undergoing rapid expansion in the late 1990s and 2000s, while spreading throughout Europe and into the Middle East. Phylogenetic analysis revealed an unstructured meticillin-resistant S. aureus (MRSA) population, lacking significant geographical or temporal clusters. The MRSA were genotypically multidrug-resistant, consistently encoded seh, and intermittently (34/194) encoded an undisrupted hlb gene with concomitant absence of the lysogenic phage-encoded genes sak and scn. All MRSA also harboured a characteristic ~5350 nt insertion in SCCmec adjacent to orfX. Detailed demographic data from Denmark showed that there, the clone is typically (25/35) found in the community, and often (10/35) among individuals with links to South-Eastern Europe. This study elucidated the evolution and epidemiology of European CC1-MRSA-IV, which emerged from a meticillin-susceptible lineage prevalent in North-Eastern Romania before disseminating rapidly throughout Europe

Tuning the electrical conductance of metalloporphyrin supramolecular wires

In contrast with conventional single-molecule junctions, in which the current flows parallel to the long axis or plane of a molecule, we investigate the transport properties of M(II)-5,15-diphenylporphyrin (M-DPP) single-molecule junctions (M=Co, Ni, Cu, or Zn divalent metal ions), in which the current flows perpendicular to the plane of the porphyrin. Novel STM-based conductance measurements combined with quantum transport calculations demonstrate that current-perpendicular-to-the-plane (CPP) junctions have three-orders-of-magnitude higher electrical conductanc than their current in-plane (CIP) counterparts, ranging from 2.10−2 G0 for Ni-DPP up to 8.10−2 G0 for Zn-DPP. The metal ion in the center of the DPP skeletons is strongly coordinated with the nitrogens of the pyridyl coated electrodes, with a binding energy that is sensitive to the choice of metal ion. We find that the binding energies of Zn-DPP and Co-DPP are significantly higher than those of Ni-DPP and Cu-DPP. Therefore when combined with its higher conductance, we identify Zn-DPP as the favoured candidate for high conductance CPP single-molecule devices

The Future of Combustion Turbine Technology for Industrial and Utility Power Generation

Low capital cost and ample low-cost natural gas supplies will make natural gas-fired combustion turbine systems the power generation technology of choice over the next decade. Against the background of earlier use by electric utilities, this paper examines the status, economic outlook, and future directions of combustion turbine technology for industrial and utility power generation. The discussion takes into account the ongoing deregulation and increasing competition that are shaping the electric power generation business. Included is a comparison between heavy-duty industrial combustion turbines and their rapidly evolving competition, aeroderivative machines, with emphasis on the appropriate application of each. The prospects for future improvements in the cost and performance of combustion turbines are reviewed, and the likely impact of advanced combustion turbine power generation concepts is considered. Also summarized is the outlook for power generation fuels, including the longer term reemergence of coal and the potential for widespread use of coal gasification-based combustion turbine systems. The paper draws heavily from a technical, economic, and business analysis, Combustion Turbine Power Systems, recently completed by SFA Pacific. The analysis was sponsored by an international group of energy companies that includes utilities, independent power producers (IPPs), and power industry equipment vendors

Coal use in the People`s Republic of China. Volume 1: Environmental impacts

The People`s Republic of China (hereafter referred to as China) is the largest producer and consumer of coal in the world. Coal makes up 76% and 74% of China`s primary energy consumption and production, respectively. This heavy dependence on coal has come at a high price for China, accounting for a large share of its environmental problems. This report examines the dominance of coal in China`s energy balance, its impact on the environment, and the need for technical and financial assistance, specifically for two distinct aspects: the effect of coal use on the environment and the importance of coal to China`s economy. The results of the analysis are presented in two volumes. Volume 1 focuses on full fuel cycle coal emissions and the environmental effects of coal consumption. Volume 2 provides a detailed analysis by sector of China`s economy and examines the economic impact of constraints on coal use. 51 refs., 19 figs., 15 tabs