241 research outputs found
Spontaneous emission of radiation by metallic electrons in the presence of electromagnetic fields of surface plasmon oscillations
The spontaneous emission of radiation of metallic electrons embedded in a
high-intensity enhanced surface plasmon field is considered analytically. The
electrons are described by exact dressed quantum states which contain the
interaction with the plasmon field non-perturbatively. Considerable deviations
from the pertubative behaviour have been found in the intensity dependence of
the emitted fundamental and the second harmonic signals, even at moderate
incoming laser intensities. The theoretical predictions deduced from the
formalism are in good qualitative agreement with the experimental results.Comment: 23 pages, 6 figure
Genetic optimization of attosecond-pulse generation in light-field synthesizers
We demonstrate control over attosecond pulse generation and shaping by
numerically optimizing the synthesis of few-cycle to sub-cycle driver
waveforms. The optical waveform synthesis takes place in an ultrabroad spectral
band covering the ultraviolet-infrared domain. These optimized driver waves are
used for ultrashort single and double attosecond pulse production (with tunable
separation) revealing the potentials of the light wave synthesizer device
demonstrated by Wirth et al. [Science 334, 195 (2011)]. The results are also
analyzed with respect to attosecond pulse propagation phenomena
UV-induced photooxidation of phenyl urea pesticides toxicology aspects
Phenylurea herbicides, like diuron, monuron, linuron, are photosynthesis inhibitors killing the entire plant by this effect. These pesticides and their intermediates formed due to their UV induced transformation could be toxic and carcinogenic to animals and humans. Thus, the investigation of the UV induced transformation of these phenyl urea pesticides from toxicology aspects is suitable. In this work, the ecotoxicology effect of the multicomponent solutions formed during the UV photolysis (254 nm) was investigated by Daphtoxkit F™ Magna and Algaltoxkit F™. The genotoxicology effect of the multicomponent solutions was investigated using the Ames tests
Synthesis, Comparative Characterization and Photocatalytic Application of SnO2/MWCNT Nanocomposite Materials
Two different preparation methods were developed to cover successfully multi-walled carbon nanotubes (MWCNT) with tin-dioxide (SnO2) nanoparticles using SnCl2.2H2O as precursor under different solvent conditions. The applied mass ratios of the components were 1:4, 1:8, 1:16, 1:32 and 1:64, respectively. As-prepared tin-dioxide coverages were characterized by TEM, SEM, SEM-EDX, Raman microscopy, BET and X-ray diffraction techniques. Photocatalytic efficiencies of selected composites were investigated in a self-made photoreactor, equipped with UV-A fluorescence lamps. Photocatalytic degradation of phenol solution was followed by using HPLC. Observations revealed that using hydrothermal method we can easily control the layer of SnO2 nanoparticles on the surface of MWCNTs. Using various solvents SnO2 nanoparticles with different morphologies formed. The nanocomposites have low photocatalytic efficiencies under conditions used generally (when lambda>300 nm)
Genetically engineered minipigs model the major clinical features of human neurofibromatosis type 1.
Neurofibromatosis Type 1 (NF1) is a genetic disease caused by mutations in Neurofibromin 1 (NF1). NF1 patients present with a variety of clinical manifestations and are predisposed to cancer development. Many NF1 animal models have been developed, yet none display the spectrum of disease seen in patients and the translational impact of these models has been limited. We describe a minipig model that exhibits clinical hallmarks of NF1, including café au lait macules, neurofibromas, and optic pathway glioma. Spontaneous loss of heterozygosity is observed in this model, a phenomenon also described in NF1 patients. Oral administration of a mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor suppresses Ras signaling. To our knowledge, this model provides an unprecedented opportunity to study the complex biology and natural history of NF1 and could prove indispensable for development of imaging methods, biomarkers, and evaluation of safety and efficacy of NF1-targeted therapies
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