4,968 research outputs found
Escherichia coli of sequence type 3835 carrying blaNDM-1, blaCTX-M-15, blaCMY-42 and blaSHV-12
New Delhi metallo-β-lactamase (NDM) represents a serious challenge for treatment and public health. A carbapenem-resistant Escherichia coli clinical strain WCHEC13-8 was subjected to antimicrobial susceptibility tests, whole genome sequencing and conjugation experiments. It was resistant to imipenem (MIC, >256 μg/ml) and meropenem (MIC, 128 μg/ml) and belonged to ST3835. blaNDM-1 was the only carbapenemase gene detected. Strain WCHEC13-8 also had a plasmid-borne AmpC gene (blaCMY-42) and two extended-spectrum β-lactamase genes (blaCTX-M-15 and blaSHV-12). blaNDM-1 and blaSHV-12 were carried by a 54-kb IncX3 self-transmissible plasmid, which is identical to plasmid pNDM-HF727 from Enterobacter cloacae. blaCMY-42 was carried by a 64-kb IncI1 plasmid and blaCTX-M-15 was located on a 141-kb plasmid with multiple F replicons (replicon type: F36:A4:B1). blaCMY-42 was in a complicated context and the mobilisation of blaCMY-42 was due to the transposition of IS Ecp1 by misidentifying its right-end boundary. Genetic context of blaNDM-1 in strain WCHEC13-8 was closely related to those on IncX3 plasmids in various Enterobacteriaceae species in China. In conclusion, a multidrug-resistant ST3835 E. coli clinical strain carrying blaNDM-1, blaCTX-M-15, blaCMY-42 and blaSHV-12 was identified. IncX3 plasmids may be making a significant contribution to the dissemination of blaNDM among Enterobacteriaceae in China
Compact and High Performance Dual-band Bandpass Filter Using Resonator-embedded Scheme for WLANs
A compact microstrip dual-band bandpass filter (DBBPF) with high selectivity and good suppression for wireless local area networks (WLANs) is proposed utilizing a novel embedded scheme resonator. Two passbands are produced by a pair of embedded half-wavelength meandered stepped-impedance resonator (MSIR) and a quadwavelength short stub loaded stepped-impedance resonator (SIR) separately. The resonator is fed by folded Tshaped capacitive source-load coupling microstrip feed line, and four transmission zeros are obtained at both sides of the bands to improve selectivity and suppression. Simultaneously, the size of the filter is extermely compact because embedding half-wavelength MSIR only changes the interior configuration of quad-wavelength SIR. To validate the design method, the designed filter is fabricated and measured. Both simulated and measured results indicate that good transmission property has been achieved
Design of Compact BPF and Planar Diplexer for UMTS using Embedded-scheme Resonator
A compact planar diplexer utilizing embedded-scheme resonator (ESR) is designed for universal mobile telecommunications system (UMTS). The ESR is formed by embedding interdigital resonators into an open loop resonator. Based on the proposed ESR, a narrowband bandpass filter suitable for diplexer design is proposed, fabricated and measured. The measured results demonstrate that the filter exhibits good transmission properties within band and high frequency selectivity. The rectangular area occupied by the filter has overall dimensions only 0.086λg by 0.105λg, promises good potential in wireless communication systems that require compact size and high encapsulation quality. Then, a compact planar diplexer operating at the TX-band of 1920-1980MHz and the RX-band of 2110-2170MHz, which is composed of a meander T-junction and two filters initially separately designed, is synthesized, simulated and measured. Both the simulated and measured results indicate that satisfied impedance matching and good isolation between two paths have been achieved
Non-pollen palynomorph assemblages in mid- to late Holocene wetland deposits and their palaeoenvironments of deposition: Microfossil signatures in sediment sequences of the Yangtze Delta coastal lowlands, East China
Fluvial processes such as sediment deposition within drainage channels and seasonal overbank flooding, and fluvial events such as occasional high intensity floods all leave particular sedimentary signatures in terms of their lithology and also in their contained microfossil assemblages, which represent different environments of deposition. Over several thousand years the Yangtze River in eastern China has developed a coastal lowland plain around its delta that is mainly composed of stacked fluvial sediment facies, but also includes many marine or estuarine layers in some areas, as well as deposits of limnic and semi-terrestrial pool, marsh and mire origin, some of which are highly organic. The fluvial facies are dominantly clastic sequences of sands, silts and clays that reflect a range of deposition from quiet water to high energy conditions and in varying water depths, mainly governed by fluvial input from the Yangtze and the many other, smaller, rivers and streams of the deltaic lowland. The limnic and marshland sediments reflect autochthonous deposition in a range of freshwater wetland types of varying water depth, from lake through marsh/fen to surface peatland. Allied to lithological and pollen data, non-pollen palynomorph spore assemblages and abundances within these complex sedimentary sequences, particularly from algal communities, provide signatures of floodplain wetland depositional history and hydrodynamic patterns. We have used groupings of these microfossil data to characterise the sedimentary facies of the lower Yangtze coastal plain and to reconstruct hydrological history across the area at a range of spatial scales. Fluctuations in the relative taxa abundances are good indicators of changes in water levels at the site scale from surface waterlogging through reedswamp and fen to deeper open water. While some changes seem to be site specific, the data show flooding and increased water depths that correlate with known phases of climatic deterioration
Note: Ultrasonic liquid flow meter for small pipes
An ultrasonic flow meter for small pipes is presented. For metal pipe diameter smaller than 10 mm, clamp-on ultrasonic contrapropagation flow meters may encounter difficulties if cross talk or the short acoustic path contributes to large uncertainty in transit time measurement. Axial inline flow meters can avoid these problems, but they may introduce other problems if the transducer port is not properly positioned. Three types of pipe connecting tees are compared using the computational fluid dynamics (CFD) method. CFD shows the 45° tee has more uniform velocity distribution over the measuring section. A prototype flow meter using the 45° tee was designed and tested. The zero flow experiment shows the flow meter has a maximum of 0.002 ms shift over 24 h. The flow meter is calibrated by only 1 meter factor. After calibration, inaccuracy lower than 0.1 of reading was achieved in the laboratory, for a measuring range from 15 to 150 gs (0.29 to 2.99 ms; Re = 2688 to 26 876). © 2012 American Institute of Physics
The Equation of State and Quark Number Susceptibility in Hard-Dense-Loop Approximation
Based on the method proposed in [ H. S. Zong, W. M. Sun, Phys. Rev. \textbf{D
78}, 054001 (2008)], we calculate the equation of state (EOS) of QCD at zero
temperature and finite quark chemical potential under the hard-dense-loop (HDL)
approximation. A comparison between the EOS under HDL approximation and the
cold, perturbative EOS of QCD proposed by Fraga, Pisarski and Schaffner-Bielich
is made. It is found that the pressure under HDL approximation is generally
smaller than the perturbative result. In addition, we also calculate the quark
number susceptibility (QNS) at finite temperature and finite chemical potential
under hard-thermal/dense-loop (HTL/HDL) approximation and compare our results
with the corresponding ones in the previous literature.Comment: 12 pages, 3 figure
Seed germination of three dominant Artemisia species in loess hilly region: alternating temperature, osmotic potential, and light effects
Non-Peer ReviewedIn this study, we evaluated the effects of alternating temperature, osmotic potential and light in the achene germination of three dominant Artemisia species (A. scoparia, A. gmelinii Web. and A. giraldii Pamp.) on arable old land after being abandoned in loess hilly region of Northern Shaanxi, in order to provide information about germination requirements which could be use for conservation studies. Results showed that A. scoparia had wider alternating temperature extremes than two other species and A. giraldii Pamp. and A. gmelinii Web. had lower optimum alternating temperature (25 oC/20 oC) than A. scoparia (30 oC/25 oC). Osmotic potential affected germination of all species significantly, but A. scoparia had better germination results than others in every treatment. In light treatments, although A. giraldii Pamp. and A. gmelinii Web. had lower germination proportion in white light, they had bigger germination proportion in darkness than A. scoparia
Is There Only One Solution of the Dyson-Schwinger Equation for Quark Propagator in the Case of Non-zero Current Quark Mass
In this letter it is shown on general ground that there exist two
qualitatively distinct solutions of the Dyson-Schwinger equation for the quark
propagator in the case of non-zero current quark mass. One solution corresponds
to the ``Nambu-Goldstone'' phase and the other one corresponds to the
``Wigner'' phase in the chiral limit.Comment: 7 page
- …