487 research outputs found
The optical properties of Poly methyl methacrylate (PMMA) polymers doped by Potassium Iodide with different thickness
Films of pure Poly (methyl methacrylate) (PMMA) doped by potassium iodide (KI) salt with percentages (1%) at different thickness prepared by casting method at room temperature. In order to study the effect of increasing thickness on optical properties, transmission and absorption spectra have been record for five different thicknesses(80,140,210,250,320)µm. The study has been extended to include the changes in the band gap energies, refractive index, extinction coefficient and absorption coefficient with thickness
The MR affect on optical properties for poly (Vinyl alcohol) films
optical properties of pure poly(vinyl Alcohol) films and poly(vinyl Alcohol) doped with methyl red were study, different percentage prepared with constant thickness using casting technique. Absorption, Transmission spectra have been recorded in order to study the optical parameters such as absorption coefficient, energy gap, refractive index, Extinction coefficient and dispersion parameters were measured in the wavelength range (200-800)nm. This study reveals that the optical properties of PVA affect by increasing the impurity concentration
Synthesis of new Polyimides Derived from 4- minoantipyrine
In the present study, new five polymers of acryloyl chloride have been synthesized by reaction 4-aminoantipyrine with many substituted acid chloride (A-E). Then condensation of polyacryloyl chloride with the product in one step (A-E), in a suitable solvent in the presence amount of (Et3N) to obtain new polyimides(A1-E5). The prepared compounds were characterized by UV. FT-IR, 1H-NMR and 13C-NMR spectroscopy and measuring of other physical properties such as softening point, melting point and solublities
Role of Salicylic Acid in the Improvement of PEG – Induced Drought Stress in Maize (Zea mays L.) cv. Baghdad
Laboratory experiment using hydroponic culture system was conducted at plant physiology laboratory, Department of Biology, College of Education for Pure Sciences, University of Basrah, in order to study the role of seeds soaking with salicylic acid (SA) and the effect of PEG8000 induced water stress on germination and early seedling growth stages of maize (Zea mays L.) cv. Baghdad. Seeds were soaked with three concentrations of SA (0.1,0.3 and 0.5 mM) in addition to control treatment with distilled water, while PEG8000 were used at concentrations of 0% (distilled water) 1%, 2%, 3%, 6%, 9% and 12%. The data was recorded on various parameters like seeds germination percentage, seedlings roots and shoot length and seedlings roots and shoot fresh and dry weight.The experiment was designed as completely randomized factorial with three replicates for each treatment. Results indicated that SA at 0.5 mM caused a significant increase in germination percentage roots and shoot length, roots and shoots fresh and dry weight while PEG8000 caused a significant decrease especially at its high concentrations (6% and 9%) in all the previous parameters. Interaction between SA at 0.5 mM and PEG had improved significantly germination percentage, shoot and roots length, shoot and roots fresh and dry weight so it had a positive significance effect on increasing the drought tolerance in maize. Keywords: Maize, Salicylic acid, PEG8000, Hydroponic, Germination, Seedling growth.
A Novel Tropically Stable Oral Amphotericin B Formulation (iCo-010) Exhibits Efficacy against Visceral Leishmaniasis in a Murine Model
Visceral leishmaniasis (VL) is a systemic form of a vector-borne parasitic disease caused by obligate intra-macrophage protozoa of the genus Leishmania. VL is always fatal in humans if left untreated and treatment options are limited. Amphotericin B (AmB), a polyene antibiotic, is the most active antileishmanial agent that currently exists. Liposomal AmB (AmBisome) is used as first-line treatment in developed countries [1], [7], [8], [9], [10]; however, the requisite parenteral administration and the high cost of the liposomal formulation prevents this treatment from reaching the majority of patients in developing nations [3]. A stable, efficacious oral treatment for VL that is able to withstand the rigors of tropical climates would overcome many of the current barriers to treatment that exist in countries with large VL-infected patient populations. In this study we have developed an oral formulation of AmB that is stable in tropical conditions and exhibits significant antileshimanial activity in mice
Sub-natural linewidth in room-temperature Rb vapor using a control laser
We demonstrate two ways of obtaining sub-natural linewidth for probe
absorption through room-temperature Rb vapor. Both techniques use a control
laser that drives the transition from a different ground state. The coherent
drive splits the excited state into two dressed states (Autler-Townes doublet),
which have asymmetric linewidths when the control laser is detuned from
resonance. In the first technique, the laser has a large detuning of 1.18 GHz
to reduce the linewidth to 5.1 MHz from the Doppler width of 560 MHz. In the
second technique, we use a counter-propagating pump beam to eliminate the
first-order Doppler effect. The unperturbed probe linewidth is about 13 MHz,
which is reduced below 3 MHz (0.5 \Gamma) at a detuning of 11.5 MHz.Comment: 4 pages, 7 figure
Loading of a Rb magneto-optic trap from a getter source
We study the properties of a Rb magneto-optic trap loaded from a commercial
getter source which provides a large flux of atoms for the trap along with the
capability of rapid turn-off necessary for obtaining long trap lifetimes. We
have studied the trap loading at two different values of background pressure to
determine the cross-section for Rb--N collisions to be 3.5(4)x10^{-14} cm^2
and that for Rb--Rb collisions to be of order 3x10^{-13} cm^2. At a background
pressure of 1.3x10^{-9} torr, we load more than 10^8 atoms into the trap with a
time constant of 3.3 s. The 1/e lifetime of trapped atoms is 13 s limited only
by background collisions.Comment: 5 pages, 5 figure
Molecular dynamics simulation of nanocolloidal amorphous silica particles: Part II
Explicit molecular dynamics simulations were applied to a pair of amorphous
silica nanoparticles of diameter 3.2 nm immersed in a background electrolyte.
Mean forces acting between the pair of silica nanoparticles were extracted at
four different background electrolyte concentrations. Dependence of the
inter-particle potential of mean force on the separation and the silicon to
sodium ratio, as well as on the background electrolyte concentration, are
demonstrated. The pH was indirectly accounted for via the ratio of silicon to
sodium used in the simulations. The nature of the interaction of the
counter-ions with charged silica surface sites (deprotonated silanols) was also
investigated. The effect of the sodium double layer on the water ordering was
investigated for three Si:Na+ ratios. The number of water molecules trapped
inside the nanoparticles was investigated as the Si:Na+ ratio was varied.
Differences in this number between the two nanoparticles in the simulations are
attributed to differences in the calculated electric dipole moment. The
implications of the form of the potentials for aggregation are also discussed.Comment: v1. 33 pages, 7 figures (screen-quality PDF), submitted to J. Chem.
Phys v2. 15 pages, 4 tables, 6 figures. Content, author list and title
changed; single space
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