1,371 research outputs found
Numerical analysis of high-index nanocomposite encapsulant for light-emitting diodes
We used two-dimensional Finte-Difference-Time-Domain (FDTD) software to study
the transition behavior of nano-particles from scatterers to an optically
uniform medium. We measured the transmission efficiency of the dipole source,
which is located in the high refractive index medium(index=2.00) and
encapsulated by low index resin(index=1.41). In an effort to compose
index-matched resin and to reduce internal reflection, high-index
nano-particles are added to low-index resin in simulations of various sizes and
densities. As the size of the nano-particles and the average spacing between
particles are reduced to 0.02 lambda and 0.07 lambda respectively, the
transmission efficiency improves two-fold compared to that without
nanoparticles. The numerical results can be used to understand the optical
behavior of nano-particles and to improve the extraction efficiency of high
brightness light-emitting-diodes(LEDs), through the use of nano-composite
encapsulant.Comment: 9 pages, 5 jpg figure
Analysis of a metallic nano-rod polarizer using finite-difference-time-domain method
The polarization behavior of metallic nano-rods has been analyzed by means of
the finite-difference-time-domain method. When the average spacing between the
nano-rods is less than a half wavelength, the layer reflects the light
polarized parallel to the nano-rods, as in a nano-slit. However, when the
spacing is larger than a half wavelength, the metallic surface absorbs the
light, polarized perpendicular to the rods, leading to a polarization reversal.
Multiple layers of nano-rods can make a polarizer with a high extinction ratio
and good transmittance
The effect of phenylephrine on the onset time of rocuronium
BACKGROUND: Several studies have demonstrated that ephedrine shortens the onset time of muscle relaxants, and it does so probably by increasing the cardiac output. However, elevation of the systemic blood pressure through α adrenergic stimulation via ephedrine may affect the onset of muscle relaxants during the induction of anesthesia. We investigated the effect of phenylephrine, which is a selective α-1 agonist, on the onset time of rocuronium and the intubating conditions in adults after the administration of propofol.
METHODS: Sixty-four patients were randomly assigned to two groups. Phenylephrine (0.9 µg/kg) (P group) or the same volume of saline (S group) was injected before rocuronium (0.6 mg/kg) administration. Anesthesia was induced with fentanyl 2 µg/kg and propofol 2 mg/kg. The onset time was defined as the time from the end of rocuronium injection to the time when a single twitch height gets to 0% or the minimum level. A well-trained anesthesiologist who was 'blinded' to the treatment groups evaluated the intubating conditions. The mean arterial pressure and heart rate were recorded before induction, before intubation, immediately after intubation and 1 minute and 2 minutes after intubation.
RESULTS: The onset time was 84 ± 18 sec in the P-group and 72 ± 14 sec in the S-group. There was no difference of the intubating conditions, the mean arterial pressure and the heart rate between the two groups.
CONCLUSIONS: A small dose of phenylephrine, which has a limited effect on blood pressure, delayed the onset time of rocuronium after the administration of propofol, and the vasoconstriction effect of phenylephrine may affect the prolongation of the rocuronium onset time at the induction of anesthesia with using propofol.ope
Taxonomic revision of the genus Lactarius (Russulales, Basidiomycota) in Korea
The genus Lactarius Pers. (Russulales) is a cosmopolitan group of Basidiomycota that forms ectomycorrhizal relationships primarily with both deciduous and coniferous trees. Although the genus has been well-studied in Europe and North America, only fragmentary researches have been carried out on Asian species. In particular, the distribution of Lactarius species in South Korea is poorly understood due to insufficient morphological descriptions and a lack of DNA sequence data. In addition, the misuse of European and North American names has added to confusion regarding the taxonomy of Asian Lactarius species. In this study, the diversity of Lactarius in South Korea was evaluated by employing both morphological and phylogenetic approaches. A multi-locus phylogenetic analysis of 729 Lactarius specimens collected between 1960 and 2017 was performed using the internal transcribed spacer (ITS) region, partial nuclear ribosomal large subunit (nrLSU), partial second largest subunit of RNA polymerase II (rpb2), and minichromosome maintenance complex component 7 (mcm7). 49 Lactarius species were identified in three Lactarius subgenera: L. subg. Russularia (17 spp.), L. subg. Lactarius (22 spp.), and L. subg. Plinthogalus (10 spp.). Among them, 28 Lactarius species were identified as new to science, while just 17 were previously described Lactarius species. Four of the taxa remain un-named due to paucity of materials. A key to Korean Lactarius species, molecular phylogenies, a summary of diversity, and detailed description are provided
Anesthetic management of a patient with nitric acid inhalation injury for extracorporeal membrane oxygenation
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