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Now showing items 145 - 160 of 227

  • Spatiotemporal patterns and determinants of dengue at county level in China from 2005-2017

    Liu, Keke   Sun, Jimin   Liu, Xiaobo   Li, Ruiyun   Wang, Yiguan   Lu, Liang   Wu, Haixia   Gao, Yuan   Xu, Lei   Liu, Qiyong  

    Objective: To identify the high risk spatiotemporal clusters of dengue cases and explore the associated risk factors. Methods: Monthly indigenous dengue cases in 2005-2017 were aggregated at county level. Spatiotemporal cluster analysis was used to explore dengue distribution features using SaTScan9.4.4 and Arcgis10.3.0. In addition, the influential factors and potential high risk areas of dengue outbreaks were analyzed using ecological niche models in Maxent 3.3.1 software. Results: We found a heterogeneous spatial and temporal distribution pattern of dengue cases. The identified high risk region in the primary cluster covered 13 counties in Guangdong Province and in the secondary clusters included 14 counties in Yunnan Province. Additionally, there was a nonlinear association between meteorological and environmental factors and dengue outbreaks, with 8.5%-57.1%, 6.7%-38.3% and 3.2%-40.4% contribution from annual average minimum temperature, land cover and annual average precipitation, respectively. Conclusions: The high risk areas of dengue outbreaks mainly are located in Guangdong and Yunnan Provinces, which are significantly shaped by environmental and meteorological factors, such as temperature, precipitation and land cover. (c) 2018 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.
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  • The study of laser self-mixing vibrometer employing different feedback regime using a VCSELS

    Lu, Liang   Zhai, Longhua   Zhang, Ke   Dai, Jijun   Zhu, Jun   Zhen, Shenglai   Yu, Benli  

    Laser interferometry based on self-mixing effect widely used to measure displacement, velocity, vibration and distance due to compactness, non-contact, as well as low cost. An important use of the self-mixing effect inside a laser diode is in optical self-mixing vibrometer. We have experimentally investigated self-mixing interference produced by the feedback flight from a vibrated target into a vertical-cavity surface-emitting laser for sensing applications. In this paper, the self-mixing vibrometer employing different feedback regime is discussed and a theoretical analysis is also proposed. Numerical analysis focused on the distortion self-mixing waveform. Numerical analysis and experimental results show that mode-hop occurs when the laser self-mixing vibrometer employing at high feedback level. (C) 2010 Elsevier GmbH. All rights reserved.
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  • Isolevuglandins covalently modify phosphatidylethanolamines in vivo: Detection and quantitative analysis of hydroxylactam adducts

    Li, Wei   Laird, James M.   Lu, Liang   Roychowdhury, Sanjoy   Nagy, Laura E.   Zhou, Rong   Crabb, John W.  

    Levuglandins (LGs) and isolevuglandins (isoLGs, also called "isoketals" or "isoKs") are extraordinarily reactive products of cyclooxygenase- and free radical-induced oxidation of arachidonates. We now report the detection in vivo and quantitative analysis of LG/isoLG adducts that incorporate the amino group of phosphatidylethanolamines (PEs) into LG/isoLG-hydroxylactams. Notably, LC-MS/MS detection of these hydroxylactams is achieved with samples that are an order of magnitude smaller and sample processing is much simpler and less time consuming than required for measuring protein-derived LG/isoLG-lysyl lactams. A key feature of our protocol is treatment of biological phospholipid extracts with phospholipase A(2) to generate mainly 1-palmitoyl-2-lysoPE-hydroxylactams from heterogeneous mixtures of phospholipids with a variety of acyl groups on the 2 position. Over 160% higher mean levels of LG/isoLG-PE-hydroxylactam (P<0.001) were detected in liver from chronic ethanol-fed mice (32.4 +/- 6.3 ng/g, n = 6) compared to controls (12.1 +/- 1.5 ng/g, n = 4), and mean levels in plasma from patients with age-related macular degeneration (5.2 +/- 0.4 ng/ml, n = 15) were elevated similar to 53% (P<0.0001) compared to those of healthy volunteers (3.4 +/- 0.1 ng/ml, n = 15). just as LG/isoLG-protein adducts provide a dosimeter of oxidative injury, this study suggests that LG/isoLG-PE-hydroxylactams are potential biomarkers for assessing risk for oxidative stress-stimulated diseases. (C) 2009 Elsevier Inc. All rights reserved
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  • Persistent infection and associated nucleotide changes of West Nile virus serially passaged in hamsters

    Wu, Xiaoyan   Lu, Liang   Guzman, Hilda   Tesh, Robert B.   Xiao, Shu-Yuan  

    Hamsters experimentally infected with the neuroinvasive West Nile virus (WNV) strain NY385-99 frequently develop persistent renal infection and viruria. Viruses recovered from the urine of such animals no longer cause neurological disease when inoculated into naive hamsters. To examine if this phenotypic change is stable, and if additional nucleotide changes occur during further passages, a urine isolate from a persistently infected hamster (WNV 9317B) was serially passaged in hamsters, and representative isolates from each passage were analysed for pathogenesis in hamsters and by nucleotide sequencing. The progeny viruses tested all resulted in asymptomatic infection when inoculated into hamsters and caused no mortality. Most of the original nucleotide changes were retained in these serial WNV isolates. Changes were distributed throughout the genome at 116 sites, ranging from 0.082 to 0.262%, compared with the parent strain NY385-99, and they were mostly in coding regions. Our findings indicate that WNV underwent additional genetic changes during serial passage in hamsters, but there was no reversion to neurotropism and virulence.
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  • Homogeneous precipitation synthesis and conductive properties of Ga-doped ZnO nanopowders

    Zheng, Ji   Zhao, Shuang   Lu, Liang   Liu, Xuejia   Song, Yangyang   Sun, Ming  

    In this paper, Ga doped ZnO (GZO) nanopowders which were synthesized via the homogeneous precipitation method were systematically investigated. The X-ray diffraction result showed that the GZO nanopowders have good crystallinity with wurtzite structure. The scanning electron microscopy image indicated that the morphology of Ga doped ZnO displayed ellipsoidal-like shaped and flake-like structure with an average grain size of about 20-30 nm. Besides, the existence of Ga was examined by X-ray photoelectron spectra, which indicated that Ga ions entered into the ZnO lattice. What's more, the influences of Ga3+ doping content, calcination atmosphere and calcination temperature on the electrical resistivity of the GZO nanopowders were studied and we found that these factors are important in controlling the electrical conductivity. In addition, the electrical resistivity was 3.142 x 10(5) Omega cm under the optimum experimental conditions.
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  • Temperature-Independent Ultrasensitive Fabry-Perot All-Fiber Strain Sensor Based on a Bubble-Expanded Microcavity

    Yin, Chenchen   Cao, Zhigang   Zhang, Zhao   Shui, Tao   Wang, Rui   Wang, Jian   Lu, Liang   Zhen, Shenglai   Yu, Benli  

    A fiber Fabry-Perot interferometer (FPI) based on a bubble-expanded microcavity is investigated in this paper. Due to the expanded bubble microcavity, the FPI exhibits high strain sensitivity of 30.66 pm/mu epsilon. To the best of our knowledge, such strain sensitivity is three to ten times higher than that of the fiber FPIs based on the microcavities previously reported. The strain response of the FPI with different shapes is analyzed, and the experimental results are consistent with the theoretical analysis.
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  • Radio frequency measurements and tuning of the China Material Irradiation Facility RFQ

    Li, Chenxing   He, Yuan   Wang, Fengfeng   Yu, Peiyan   Yang, Lei   Li, Chunlong   Wang, Wenbin   Xu, Xianbo   Shi, Longbo   Ma, Wei   Sun, Liepeng   Lu, Liang   Wang, Zhijun   Shi, Aimin   Wang, Tieshan  

    The full assembly and alignment of the China Material Irradiation Facility RFQ have been completed. Before the completion, the assembly and braze of single segments had been done. Radio frequency measurements of each module with dummy extension undercuts were performed before and after braze. The results reveal that there is no unexpected deformation after braze. After the full assembly, RF measurements and tuning have been performed in order to compensate the errors originated from the fabrication, braze and assembly. The impact of these errors on the field distribution is depressed to a level that is restricted by beam dynamics simulation. In this paper, the procedure of radio frequency measurement and tuning will be expatiated and the ultimate RF parameters of the cavity after tuning will be presented.
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  • How does the dengue vector mosquito Aedes albopictus respond to global warming?

    Jia, Pengfei   Chen, Jin   Lu, Liang   Liu, Qiyong   Tan, Xiaoyue  

    Background: Global warming has a marked influence on the life cycle of epidemic vectors as well as their interactions with human beings. The Aedes albopictus mosquito as the vector of dengue fever surged exponentially in the last decade, raising ecological and epistemological concerns of how climate change altered its growth rate and population dynamics. As the global warming pattern is considerably uneven across four seasons, with a confirmed stronger effect in winter, an emerging need arises as to exploring how the seasonal warming effects influence the annual development of Ae. albopictus.Methods: The model consolidates a 35-year climate dataset and designs fifteen warming patterns that increase the temperature of selected seasons. Based on a recently developed mechanistic population model of Ae. albopictus, the model simulates the thermal reaction of blood-fed adults by systematically increasing the temperature from 0.5 to 5 degrees C at an interval of 0.5 degrees C in each warming pattern.Results: The results show the warming effects are different across seasons. The warming effects in spring and winter facilitate the development of the species by shortening the diapause period. The warming effect in summer is primarily negative by inhibiting mosquito development. The warming effect in autumn is considerably mixed. However, these warming effects cannot carry over to the following year, possibly due to the fact that under the extreme weather in winter the mosquito fully ceases from development and survives in terms of diapause eggs.Conclusions: As the historical pattern of global warming manifests seasonal fluctuations, this study provides corroborating and previously ignored evidence of how such seasonality affects the mosquito development. Understanding this short-term temperature-driven mechanism as one chain of the transmission events is critical to refining the thermal reaction norms of the epidemic vector under global warming as well as developing effective mosquito prevention and control strategies.
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  • The design of rapid turbidity measurement system based on single photon detection techniques

    Yang, Yixin   Wang, Huanqin   Cao, Yangyang   Gui, Huaqiao   Liu, Jianguo   Lu, Liang   Cao, Huibin   Yu, Tongzhu   You, Hui  

    A new rapid turbidity measurement system has been developed to measure the turbidity of drinking water. To determinate the turbidity quantitatively, the total intensity of scattering light has been measured and quantified as number of photons by adopting the single photon detection techniques (SPDT) which has the advantage of high sensitivity. On the basis of SPDT, the measurement system has been built and series of experiments have been carried out. Combining then the 90 degrees Mie scattering theory with the principle of SPDT, a turbidity measurement model has been proposed to explain the experimental results. The experimental results show that a turbidity, which is as low as 0.1 NTU (Nephelometric Turbidity Units), can be measured steadily within 100 ms. It also shows a good linearity and stability over the range of 0.1-400 NTU and the precision can be controlled within 5% full scale. In order to improve its precision and stability, some key parameters, including the sampling time and incident light intensity, have been discussed. It has been proved that, to guarantee an excellent system performance, a good compromise between the measurement speed and the low power consumption should be considered adequately depending on the practical applications. (C) 2015 Elsevier Ltd. All rights reserved.
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  • Mass spectrometry characterization of the thermal decomposition/digestion (TDD) at cysteine in peptides and proteins in the condensed phase.

    Basile, Franco   Zhang, Shaofeng   Kandar, Sujit Kumar   Lu, Liang  

    We report on the characterization by mass spectrometry (MS) of a rapid, reagentless and site-specific cleavage at the N-terminus of the amino acid cysteine (C) in peptides and proteins induced by the thermal decomposition at 220-250 degreesC for 10 s in solid samples. This thermally induced cleavage at C occurs under the same conditions and simultaneously to our previously reported thermally induced site-specific cleavage at the C-terminus of aspartic acid (D) (Zhang, S.; Basile, F. J. Proteome Res. 2007, 6, (5), 1700-1704). The C cleavage proceeds through cleavage of the nitrogen and alpha-carbon bond (N-terminus) of cysteine and produces modifications at the cleavage site with an amidation (-1 Da) of the N-terminal thermal decomposition product and a -32 Da mass change of the C-terminal thermal decomposition product, the latter yielding either an alanine or beta-alanine residue at the N-terminus site. These modifications were confirmed by off-line thermal decomposition electrospray ionization (ESI)-MS, tandem MS (MS/MS) analyses and accurate mass measurements of standard peptides. Molecular oxygen was found to be required for the thermal decomposition and cleavage at C as it induced an initial cysteine thiol side chain oxidation to sulfinic acid. Similar to the thermally induced D cleavage, missed cleavages at C were also observed. The combined thermally induced digestion process at D and C, termed thermal decomposition/digestion (TDD), was observed on several model proteins tested under ambient conditions and the site-specificity of the method confirmed by MS/MS.
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  • Piezoresistive behavior study on finger-sensing silicone rubber/graphite nanosheet nanocomposites

    Chen, Ling   Chen, Guohua   Lu, Liang  

    A novel finger-sensing nanocomposite with remarkable and reversible piezoresistivity is successfully fabricated by dispersing homogeneously conductive graphite nanosheets (GNs) in a silicone rubber (SR) matrix. Because of the high aspect ratio of the graphite nanosheets, the nanocomposite displays a very low percolation threshold. The SR/GN nanocomposite with a volume fraction of conductive nanosheets closest to that for the percolation threshold presents a sharp positive-pressure coefficient effect of the resistivity under very low pressure, namely, in the finger-pressure range (0.3-0.7 MPa), whereby the abrupt transitive behavior of the nanocomposite is accounted for by an extension of the tunneling conduction theory which provides a good approximation of the piezoresistive effect.
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  • Are QCA Cryptographic Circuits Resistant to Power Analysis Attack?

    Liu, Weiqiang   Srivastava, Saket   Lu, Liang   O'Neill Nee Mcloone, Maire   Swartzlander, Earl E., Jr.  

    Quantum-dot cellular automata (QCA) technology is expected to offer fast computation performance, high density, and low power consumption. Thus, researchers believe that QCA may be an attractive alternative to CMOS for future digital designs. Side channel attacks, such as power analysis attacks, have become a significant threat to the security of CMOS cryptographic circuits. A power analysis attack can reveal the secret key from measurements of the power consumption during the encryption and decryption process. As there is no electric current flow in QCA technology, the power consumption of QCA circuits is extremely low when compared to their CMOS counterparts. Therefore, in this paper an investigation into both the best and worst case scenarios for attackers is carried out to ascertain if QCA circuits are immune to power analysis attack. A QCA design of a submodule of the Serpent cipher is proposed. In comparison to a previous design, the proposed design is more efficient in terms of complexity, area, and latency. By using an upper bound power model, the first power analysis attack of a QCA cryptographic circuit is presented. The simulation results show that even though the power consumption is low, it can still be correlated with the correct key guess, and all possible subkeys applied to the Serpent submodule can be revealed in the best case scenario. Therefore, in theory QCA cryptographic circuits would be vulnerable to power analysis attack. However, the security of practical QCA devices can be greatly improved by applying a smoother clock. Moreover, in the worst case scenario, the design of logically reversible QCA circuits with Bennett clocking could be used as a natural countermeasure to power analysis attack. Therefore, it is believed that QCA could be a niche technology in the future for the implementation of security architectures resistant to power analysis attack.
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  • Wideband Ceiling-Mount Omnidirectional Antenna for Indoor Distributed Antenna Systems

    Zhou, Lei   Jiao, Yongchang   Qi, Yihong   Weng, Zibin   Lu, Liang  

    A wideband omnidirectional antenna is presented in this letter. The proposed antenna consists of three radiators over a ground plane, a monopole composed of three patches fed by a coaxial line, a coupling patch with three shorting legs above the monopole to extend the lowest frequencies of operation, and a top-loading disk located on the top of the coupling patch for further decreasing the lowest frequencies of operation. An enhanced impedance bandwidth of 9.23:1 ranging from 650 MHz to 6 GHz with S-11 < -13.9 dB (for SWR <= 1.5) is achieved. The antenna meets network operator's requirements for cellular bands and has good radiation efficiency in the WiFi bands. The proposed antenna can be widely used in indoor distributed antenna systems, such as 3G, 4G LTE, and WiFi (2.4 and 5.8 GHz) bands. The antenna is simulated by ANSYS HFSS and measured in a microwave anechoic chamber. The simulated and measured results show good agreement.
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  • Wideband Circularly Polarized Antenna With Stair-Shaped Dielectric Resonator and Open-Ended Slot Ground

    Lu, Liang   Jiao, Yong-Chang   Zhang, Huan   Wang, Ruiqi   Li, Tian  

    A novel wideband circularly polarized (CP) antenna with a stair-shaped dielectric resonator and an open-ended slot ground is introduced. By adjusting parameter values of the hybrid structure, wideband CP characteristics can be realized. In order to improve the impedance matching and enhance the axialratio (AR) bandwidth, the open-ended slot is also inserted in the ground plane. The antenna is fully studied and manufactured. Measured results show that the proposed antenna has 10-dB return loss of 71.7% (3.844-8.146 GHz) and 3-dB AR bandwidths of 46.0% (4.15-6.63 GHz), respectively, and a peak gain of 3.9 dBic. In addition, more than 92% antenna radiation efficiency is obtained.
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  • Effects of socio-economic and environmental factors on the spatial heterogeneity of dengue fever investigated at a fine scale.

    Qu, Yubing   Shi, Xun   Wang, Yong   Li, Rendong   Lu, Liang   Liu, Qiyong  

    The spatial pattern of dengue fever cases is the result of complex interactions between the virus, the host and the vector, which may be affected by environmental conditions. The largest outbreak of dengue fever in Guangzhou city, China occurred in 2014 with case numbers 2.7 times the number of cumulative cases since 1978 and a significantly non-random spatial distribution. Selecting Guangzhou City as the study area, we used scan statistics to analyze the spatial heterogeneity of dengue fever and a generalized additive model to evaluate and examine the effects of socio-economic and environmental factors on spatial heterogeneity at a fine scale. The study found that the spatial distribution of dengue fever is highly heterogeneous and various factors differ in relative importance. The junction of the central districts of Guangzhou is a high-risk area with the urban village and urban-rural fringe zone formed by urbanization as important regional factors. The low gross domestic product per capita, the high population density, the high road density were perceived as risk factors. The Asian subtropical coastal area together with the socioeconomic and environmental factors were found to be the key drivers at the fine scale explaining the high spatial heterogeneity of dengue fever in Guangzhou City.=20
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  • Population Genomics Reveals Speciation and Introgression between Brown Norway Rats and Their Sibling Species

    Teng, Huajing   Zhang, Yaohua   Shi, Chengmin   Mao, Fengbiao   Cai, Wanshi   Lu, Liang   Zhao, Fangqing   Sun, Zhongsheng   Zhang, Jianxu  

    Murine rodents are excellent models for study of adaptive radiations and speciation. Brown Norway rats (Rattus norvegicus) are successful global colonizers and the contributions of their domesticated laboratory strains to biomedical research are well established. To identify nucleotide-based speciation timing of the rat and genomic information contributing to its colonization capabilities, we analyzed 51 whole-genome sequences of wild-derived Brown Norway rats and their sibling species, R. nitidus, and identified over 20 million genetic variants in the wild Brown Norway rats that were absent in the laboratory strains, which substantially expand the reservoir of rat genetic diversity. We showed that divergence of the rat and its siblings coincided with drastic climatic changes that occurred during the Middle Pleistocene. Further, we revealed that there was a geographically widespread influx of genes between Brown Norway rats and the sibling species following the divergence, resulting in numerous introgressed regions in the genomes of admixed Brown Norway rats. Intriguing, genes related to chemical communications among these introgressed regions appeared to contribute to the population-specific adaptations of the admixed Brown Norway rats. Our data reveals evolutionary history of the Brown Norway rat, and offers new insights into the role of climatic changes in speciation of animals and the effect of interspecies introgression on animal adaptation.
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