876 research outputs found
Electromagnetic wave propagation through a dielectric-chiral interface and through a chiral slab
The reflection from and transmission through a semi-infinite chiral medium are analyzed by obtaining the Fresnel equations in terms of parallel- and perpendicular-polarized modes, and a comparison is made with results reported previously. The chiral medium is described electromagnetically by the constitutive relations D = εE + iγB and H = iγE + (1/μ)B. The constants ε, μ, and γ are real and have values that are fixed by the size, the shape, and the spatial distribution of the elements that collectively compose the medium. The conditions are obtained for the total internal reflection of the incident wave from the interface and for the existence of the Brewster angle. The effects of the chirality on the polarization and the intensity of the reflected wave from the chiral half-space are discussed and illustrated by using the Stokes parameters. The propagation of electromagnetic waves through an infinite slab of chiral medium is formulated for oblique incidence and solved analytically for the case of normal incidence
Nutritional value of raw soybeans, extruded soybeans, roasted soybeans and tallow as fat sources in early lactating dairy cows
Thirty multiparous Holstein cows (29.8 ± 4.01days in milk; 671.6 ± 31.47 kg of body weight) were used in a completely randomized design to compare nutritional value of four fat sources including tallow, raw soybeans, extruded soybeans and roasted soybeans for 8 weeks. Experimental diets were a control containing 27.4 % alfalfa silage, 22.5% corn silage, and 50.1% concentrate, and four diets with either tallow, raw soybean, extruded soybean, or roasted soybean added to provide 1.93% supplemental fat. Dry matter and NEL intakes were similar among treatments, while cows fed fat diets had significantly (P<0.05) high NEL intakes when compared to control with no fat. Supplemental fat, whether tallow or full fat soybeans increased milk production (1.89-2.45 kg/d; P<0.01) and FCM production (1.05-2.79; P<0.01). Milk fat yield and percentage of cows fed fat-supplemented diets were significantly (P<0.01 and P<0.05 respectively) higher than control. Between fat-supplemented diets, roasted soybean caused highest milk fat yield and extruded soybean caused lowest milk fat yield. There was no significant effect of supplemental fat on the milk protein and lactose content and yield. Feed efficiency of fat-supplemented diets was significantly (P<0.01) higher than control. Body weight, body weight change and BCS (body condition score) of cows, as well as energy balance and energy efficiency were similar between treatments. In conclusion, while there was no significant effect of fat sources on production response of cows, fat originating from heat-treated soybean help to minimize imported RUP (rumen undegradable protein) sources level as fish meal in comparison with tallow and raw soybean oil. In the Current study, there was no statistical significance among nutritional values of oil from extruded soybeans and roasted soybeans
X-linked lymphoproliferative disease (XLP)
Review on X-linked lymphoproliferative disease (XLP), with data on clinics, and the genes involved
Coronary graft patency after perioperative myocardial infarction: a study with multislice computed tomography
A total of 55 consecutive patients who experienced perioperative myocardial infarction (MI) after coronary artery bypass grafting were
studied using multislice computed tomography (MSCT) angiography to evaluate for graft patency. The MSCT detected acute graft occlusion
in 23% grafts. Of the 55 patients, 40% patients had occluded grafts and perioperative MI in the area of the grafted vessels; remaining 60%
had patent grafts with infarction in the area of the grafted vessels. Compared with the patients with patent grafts, those with occluded
grafts had a higher blood sugar level. In addition, graft occlusion was higher in grafts with severe distal disease. Among the patients with
patent grafts, luminal stenosis of the native vessels supplying the infarcted myocardium was higher than that in the native vessels supplying
the non-infarcted myocardium. In conclusion, MSCT is feasible for the assessment of graft patency in the setting of perioperative MI. Graft
occlusion is detected in less than half of the cases and usually occurs in the grafts with severe distal involvement and the patients with
uncontrolled hyperglycemia. In patients with patent grafts, the severity of luminal stenosis of the native grafted vessel is the main
predisposing factor for perioperative MI
Risk factors associated with heart valve thrombosis in patients with prosthetic heart valve dysfunction
Background: Thrombotic and thromboembolic events are important causes of mortality and morbidity in patients with prosthetic heart valve. The aim of this study is to evaluate the factors that may contribute to prosthetic heart valve thrombosis. Methods: This was a cross-sectional study in Rajaie Heart Center on patients with prosthetic heart valve malfunction, within a year. According to the echocardiographic and fluoroscopic findings, the patients were divided into two groups (thrombosis and non-thrombosis groups). The patients' demographic, clinical and laboratory data were recorded and analyzed with SPSS software. Results: A total of 142 patients participated in this study. Ninety-four patients (66.2) were diagnosed with thrombosis. There was a significant relationship between thrombosis and inadequate anti-coagulation (international normalized rati INR <2.5) (odds ratio OR: 4.15, 95% CI: 1.98-9.87, P = 0.003), history of infection (OR: 12.81, 95% CI: 3.52-19.02, P < 0.001), prothrombin time (PT) check interval (OR: 2.38, 95% CI: 1.63-8.47, P = 0.019), atrial fibrillation (AF) rhythm (OR: 3.96, 95% CI: 1.75-8.09, P = 0.019), and plasma fibrinogen level (OR: 6.90, 95% CI: 2.58-14.69). Conclusion: Based on this study, inadequate anti-coagulation, AF rhythm, recent infection and plasma fibrinogen level were the factors most contributing to prosthetic valve thrombosis. As there were many cases of thrombosis in patients with history of infection, this factor can be considered for risk assessment in prosthetic valve. © 2020 The Author(s)
Theory of the propagation of coupled waves in arbitrarily-inhomogeneous stratified media
We generalize the invariant imbedding theory of the wave propagation and
derive new invariant imbedding equations for the propagation of arbitrary
number of coupled waves of any kind in arbitrarily-inhomogeneous stratified
media, where the wave equations are effectively one-dimensional. By doing this,
we transform the original boundary value problem of coupled second-order
differential equations to an initial value problem of coupled first-order
differential equations, which makes the numerical solution of the coupled wave
equations much easier. Using the invariant imbedding equations, we are able to
calculate the matrix reflection and transmission coefficients and the wave
amplitudes inside the inhomogeneous media exactly and efficiently. We establish
the validity and the usefulness of our results by applying them to the
propagation of circularly-polarized electromagnetic waves in one-dimensional
photonic crystals made of isotropic chiral media. We find that there are three
kinds of bandgaps in these structures and clarify the nature of these bandgaps
by exact calculations.Comment: 7 pages, 1 figure, to appear in Europhys. Let
Responsive glyco-poly(2-oxazoline)s: synthesis, cloud point tuning, and lectin binding
A new sugar-substituted 2-oxazoline monomer was prepared using the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. Its copolymerization with 2-ethyl-2-oxazoline as well as 2-(dec-9-enyl)-2-oxazoline, yielding well-defined copolymers with the possibility to tune the properties by thiol-ene "click" reactions, is described. Extensive solubility studies on the corresponding glycocopolymers demonstrated that the lower critical solution temperature behavior and pH-responsiveness of these copolymers can be adjusted in water and phosphate-buffered saline (PBS) depending on the choice of the thiol. By conjugation of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose and subsequent deprotection of the sugar moieties, the hydrophilicity of the copolymer could be increased significantly, allowing a cloud-point tuning in the physiological range. Furthermore, the binding capability of the glycosylated copoly(2-oxazoline) to concanavalin A was investigated
Investigation of mechanical losses of thin silicon flexures at low temperatures
The investigation of the mechanical loss of different silicon flexures in a
temperature region from 5 to 300 K is presented. The flexures have been
prepared by different fabrication techniques. A lowest mechanical loss of
was observed for a 130 m thick flexure at around 10 K.
While the mechanical loss follows the thermoelastic predictions down to 50 K a
difference can be observed at lower temperatures for different surface
treatments. This surface loss will be limiting for all applications using
silicon based oscillators at low temperatures. The extraction of a surface loss
parameter using different results from our measurements and other references is
presented. We focused on structures that are relevant for gravitational wave
detectors. The surface loss parameter = 0.5 pm was obtained. This
reveals that the surface loss of silicon is significantly lower than the
surface loss of fused silica.Comment: 16 pages, 7 figure
Astrometry and geodesy with radio interferometry: experiments, models, results
Summarizes current status of radio interferometry at radio frequencies
between Earth-based receivers, for astrometric and geodetic applications.
Emphasizes theoretical models of VLBI observables that are required to extract
results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the
achievements of VLBI during the past two decades in reference frames, Earth
orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys.,
Vol. 70, Oct. 199
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