Terahertz generation in multiple laser-induced air plasmas

This is the published version. Copyright 2008 American Institute of PhysicsAn investigation of the terahertz wavegeneration in multiple laser-induced air plasmas is presented. First, it is demonstrated that the intensity of the terahertz wave increases as the number of air plasmas increases. Second, the physical mechanism of this enhancement effect of the terahertz generation is studied by quantitatively measuring the intensity of the generated terahertz wave as a function of phase difference between adjacent air plasmas. It is found out that the superposition is the main mechanism to cause this enhancement. Thus, the results obtained in this paper not only provide a technique to generate stronger terahertz wave but also enable a better understanding of the mechanism of the terahertz generation in air plasma

Is clopidogrel better than aspirin following breakthrough strokes while on aspirin? A retrospective cohort study.

ObjectiveThere is insufficient evidence on which to base a recommendation for optimal antiplatelet therapy following a stroke while on aspirin. The objective was to compare clopidogrel initiation vs aspirin reinitiation for vascular risk reduction among patients with ischaemic stroke on aspirin at the time of their index stroke.DesignRetrospective.SettingWe conducted a nationwide cohort study by retrieving all hospitalised patients (≥18 years) with a primary diagnosis of ischaemic stroke between 2003 and 2009 from Taiwan National Health Insurance Research Database.ParticipantsAmong 3862 patients receiving aspirin before the index ischaemic stroke and receiving either aspirin or clopidogrel after index stroke during follow-up period, 1623 were excluded due to a medication possession ratio <80%. Also, 355 were excluded due to history of atrial fibrillation, valvular heart disease or coagulopathy. Therefore, 1884 patients were included in our final analysis.InterventionsPatients were categorised into two groups based on whether clopidogrel or aspirin was prescribed during the follow-up period. Follow-up was from time of the index stroke to admission for recurrent stroke or myocardial infarction, death or the end of 2010.Primary and secondary outcome measuresThe primary end point was hospitalisation due to a new-onset major adverse cardiovascular event (MACE: composite of any stroke or myocardial infarction). The leading secondary end point was any recurrent stroke.ResultsCompared to aspirin, clopidogrel was associated with a lower occurrence of future MACE (HR=0.54, 95% CI 0.43 to 0.68, p<0.001, number needed to treat: 8) and recurrent stroke (HR=0.54, 95% CI 0.42 to 0.69, p<0.001, number needed to treat: 9) after adjustment of relevant covariates.ConclusionsAmong patients with an ischaemic stroke while taking aspirin, clopidogrel initiation was associated with fewer recurrent vascular events than aspirin reinitiation

The flow back tracing and DDoS defense mechanism of the TWAREN defender cloud

The TWAREN Defender Cloud is a distributed filter platform on thenetwork backbone to help defending our connecting institutions against maliciousnetwork attacks. By combining the security reports from participating schools, thissystem can block the incoming threats from the entry points, thus it helps protectingall connecting institutions in the most economic and effective way. This paper aimedat explaining the analyzer design, its mechanism to back trace DDoS attack flows totheir entry points and the defense mechanism it provides to block the threats

An Investigation of Factors Affecting Elementary School Students’ BMI Values Based on the System Dynamics Modeling

This study used system dynamics method to investigate the factors affecting elementary school students’ BMI values. The construction of the dynamic model is divided into the qualitative causal loop and the quantitative system dynamics modeling. According to the system dynamics modeling, this study consisted of research on the four dimensions: student’s personal life style, diet-relevant parenting behaviors, advocacy and implementation of school nutrition education, and students’ peer interaction. The results of this study showed that students with more adequate health concepts usually have better eating behaviors and consequently have less chance of becoming obese. In addition, this study also verified that educational attainment and socioeconomic status of parents have a positive correlation with students’ amounts of physical activity, and nutrition education has a prominent influence on changing students’ high-calorie diets

Analysis of terahertz generation via nanostructure enhanced plasmonic excitations

This is the published version. Copyright © 2009 American Institute of PhysicsIn this paper, we conduct a quantitative study on the physical mechanism of electrons dynamics near the nanostructured metalfilmsurfaces, as well as the efficiency of generated terahertz radiation associated with different types of nanostructures. The simulation results show that although the oscillating motion of emitted electrons outside the metal surface may affect the terahertz generation efficiency to some extent, this efficiency is predominantly determined by the electric field magnitude inside the metalfilm associated with nanostructure enhanced plasmonic excitations. Due to the field enhancement effect of the nanostructure, an appropriately designed nanostructured surface could greatly enhance the strength of generated terahertz signal via the increased nonlinear interactions between the light and the nanostructures

Detection of concealed and buried chemicals by using multifrequency excitations

This is the published version. Copyright © 2010 American Institute of PhysicsIn this paper, we present a new type of concealed and buried chemical detection system by stimulating and enhancing spectroscopic signatures with multifrequency excitations, which includes a low frequency gradient dcelectric field, a high frequency microwave field, and higher frequency infrared (IR) radiations. Each excitation frequency plays a unique role. The microwave, which can penetrate into the underground and/or pass through the dielectric covers with low attenuation, could effectively transform its energy into the concealed and buried chemicals and increases its evaporation rate from the sample source. Subsequently, a gradient dcelectric field, generated by a Van De Graaff generator, not only serves as a vapor accelerator for efficiently expediting the transportation process of the vapor release from the concealed and buried chemicals but also acts as a vapor concentrator for increasing the chemical concentrations in the detection area, which enables the trace level chemical detection. Finally, the stimulated and enhanced vapors on the surface are detected by the IR spectroscopic fingerprints. Our theoretical and experimental results demonstrate that more than sixfold increase in detection signal can be achieved by using this proposed technology. The proposed technology can also be used for standoff detection of concealed and buried chemicals by adding the remote IR and/or thermal spectroscopic and imaging detection systems

Asian dust input in the western Philippine Sea: Evidence from radiogenic Sr and Nd isotopes

The radiogenic strontium (Sr) and neodymium (Nd) isotope compositions of the detrital fraction of surface and subsurface sediments have been determined to trace sediment provenance and contributions from Asian dust off the east coast of Luzon Islands in the western Philippine Sea. The Sr and Nd isotope compositions have been very homogenous near the east coast of the Luzon Islands during the latest Quaternary yielding relatively least radiogenic Sr (87Sr/86Sr = 0.70453 to 0.70491) and more radiogenic Nd isotope compositions (εNd(0) = +5.3 to +5.5). These isotope compositions are similar to Luzon rocks and show that these sediments were mainly derived from the Luzon Islands. In contrast, the Sr and Nd isotope compositions of sediments on the Benham Rise and in the Philippine Basin are markedly different in that they are characterized by overall more variable and more radiogenic Sr isotope compositions (87Sr/86Sr = 0.70452 to 0.70723) and less radiogenic Nd isotope compositions (εNd(0) = −5.3 to +2.4). The Sr isotope composition in the Huatung Basin is intermediate between those of the east coast of Luzon and Benham Rise, but shows the least radiogenic Nd isotope compositions. The data are consistent with a two end-member mixing relationship between Luzon volcanic rocks and eolian dust from the Asian continent, which is characterized by highly radiogenic Sr and unradiogenic Nd isotope compositions. The results show that Asian continental dust contributes about 10–50% of the detrital fraction of the sediments on Benham Rise in the western Philippine Sea, which offers the potentials to reconstruct the climatic evolution of eastern Asia from these sediments and compare this information to the records from the central and northern Pacific

RUNX3 Mediates Suppression of Tumor Growth and Metastasis of Human CCRCC by Regulating Cyclin Related Proteins and TIMP-1

Here we presented that the expression of RUNX3 was significantly decreased in 75 cases of clear cell renal cell carcinoma (CCRCC) tissues (p<0.05). Enforced RUNX3 expression mediated 786-O cells to exhibit inhibition of growth, G1 cell-cycle arrest and metastasis in vitro, and to lost tumorigenicity in nude mouse model in vivo. RUNX3-induced growth suppression was found partially to regulate various proteins, including inhibition of cyclinD1, cyclinE, cdk2, cdk4 and p-Rb, but increase of p27Kip1, Rb and TIMP-1. Therefore, RUNX3 had the function of inhibiting the proliferative and metastatic abilities of CCRCC cells by regulating cyclins and TIMP1