Kinetička Bunemanova nestabilnost u prašnjavoj plazmi u različitim temperaturnim uvjetima

Recent theoretical work on the excitation of Buneman\u27s instability in inhomogeneous anisotropic dusty plasmas is presented. Plasmas with different temperature regime are considered. The dispersion relation is derived and solved for a 1-D Buneman instability excited in such plasmas. Electron to ion temperature ratio, degree of plasma inhomogeneity and dust grains thermal velocity are found to play a crucial role in the growth and damping of Buneman instability.Predstavljamo nedavna teorijska istraživanja uzbude Bunemanove nestabilnosti u nehomogenim anizotropnim prašnjavim plazmama. Razmatramo plazme u različitim temperaturnim uvjetima. Izvodimo disperzijsku relaciju i rješavamo 1D Bunemanovu nestabilnost uzbuđenu u takvim plazmama. Nalazimo da su omjer temperature elektrona i iona, stupanj nejednolikosti plazme i toplinska brzina zrnaca prašine ključni za rast i gušenje Bunemanove nestabilnosti

Kinetička Bunemanova nestabilnost u prašnjavoj plazmi u različitim temperaturnim uvjetima

Recent theoretical work on the excitation of Buneman\u27s instability in inhomogeneous anisotropic dusty plasmas is presented. Plasmas with different temperature regime are considered. The dispersion relation is derived and solved for a 1-D Buneman instability excited in such plasmas. Electron to ion temperature ratio, degree of plasma inhomogeneity and dust grains thermal velocity are found to play a crucial role in the growth and damping of Buneman instability.Predstavljamo nedavna teorijska istraživanja uzbude Bunemanove nestabilnosti u nehomogenim anizotropnim prašnjavim plazmama. Razmatramo plazme u različitim temperaturnim uvjetima. Izvodimo disperzijsku relaciju i rješavamo 1D Bunemanovu nestabilnost uzbuđenu u takvim plazmama. Nalazimo da su omjer temperature elektrona i iona, stupanj nejednolikosti plazme i toplinska brzina zrnaca prašine ključni za rast i gušenje Bunemanove nestabilnosti

Inhibition of phage infection in capsule-producing Streptococcus thermophilus using concanavalin A, lysozyme and saccharides

Lactic cultures that produce capsular polysaccharides are widely used in the dairy industry. However, little information is available on their phage-cell interactions. Concanavalin A (Con A), lysozyme, andsaccharides were investigated for their ability to modify phage-cell interactions in such a manner as to inhibit phage infection. The ability of phage to infect cells was determined by measuring acidproduction in Elliker broth. Acid production by capsule-producing Streptococcus thermophilus was inhibited less by bacteriophage when cells were pretreated with Con. A than was acid production by acapsule-free variant. The presence of 0.5 mg/ml lysozyme in Elliker broth significantly reduced phage infection. However, there was no increased effect when lysozyme and Con A were combined in thegrowth medium. The addition of 5 g/L of glucosamine to Elliker broth also inhibited phage infection. The results of this study indicate that it is possible to reduce phage infection of capsule-forming S.thermophilus by blocking or modifying phage adsorption sites

Advances in the Analytical Methods for Determining the Antioxidant Properties of Honey: A Review

Free radicals and reactive oxygen species (ROS) have been implicated in contributing to the processes of aging and disease. In an effort to combat free radical activity, scientists are studying the effects of increasing individuals' antioxidant levels through diet and dietary supplements. Honey appears to act as an antioxidant in more ways than one. In the body, honey can mop up free radicals and contribute to better health. Various antioxidant activity methods have been used to measure and compare the antioxidant activity of honey. In recent years, DPPH (Diphenyl-1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power), ORAC (The Oxygen Radical Absorbance Capacity), ABTS [2, 2-azinobis (3-ehtylbenzothiazoline-6-sulfonic acid) diamonium salt], TEAC [6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid (Trolox)-equivalent antioxidant capacity] assays have been used to evaluate antioxidant activity of honey. The antioxidant activity of honey is also measured by ascorbic acid content and different enzyme assays like Catalase (CAT), Glutathione Peroxidase (GPO), Superoxide Dismutase (SOD). Among the different methods available, methods that have been validated, standardized and widely reported are recommended.Key words: Honey; antioxidant properties; DPPH; FRAP; ORAC; TEAC; ABT

Prolonged heating of honey increases its antioxidant potential but decreases its antimicrobial activity

Background: Honey is renowned for its antioxidant, antimicrobial and medicinal properties. It is typically heated and filtered during processing to avoid crystallization. However, few studies have reported its heating effect and the antioxidant and antimicrobial activities of honey.Materials and Methods: In this study, honey samples were collected from eight different honey-producing sites in Bangladesh and heated to 50ºC, 70ºC and 90ºC for 12 hours, while the antioxidant potentials and antimicrobial properties of the heated samples were compared with those of the unheated samples. Antimicrobial properties were investigated against one Gram-positive and eight Gram-negative bacteria. Other physicochemical and biochemical properties were also determined.Results: Interestingly, there was a proportionate increase in the amount of antioxidant compounds (phenolics and flavonoids) as well as antioxidant potentials proportional with the amount of heat introduced, whereas the antimicrobial properties of the honey samples were reduced with increasing heat.Conclusion: In conclusion, though prolonged heat treatment of honey can increase its antioxidant potential, antimicrobial activities are compromised.Keywords: Honey, heat, antioxidant, antimicrobial

Spice Foods effects on Body Weight Reductions between Obese Animal Models

The aim of this study was determination and identification of phenolic and flavonoids fraction in addition to the antioxidant activities of used herbals (curcumin, black pepper and cumin) by HPLC in addition to evaluating the effects of such different spicy food consumptions on body weight reduction between obese animal models. Rats were randomly divided to ten groups fed; Black Papers, Cumin and Curcumin either alone or in different mixtures additionally to groups fed Orlistat (control body weight loss), Non-obese negative control group (C-ve) and Obese control positive group (C+ve). Blood glucose and body weight levels were measured at the beginning and end of the experimental in addition to rats’ lipid profiles (total cholesterol; triglycerides;, high dense lipoprotein cholesterol; low dense lipoprotein cholesterol; and very low dense lipoprotein cholesterol). Results presented that obese models received (Cumin)  Cu/( Curcumin ) Cur mixture have the biggest effective significant treatment (about -80% body weight reduction  ) followed by both groups fed mixtures of (Curcumin ) Cur/( Black Papers ) Bp  and (Curcumin) Cur/( Black Papers ) Bp/( Cumin ) Cu; decreased by -68.0 and -65.6g respectively. The study could be more valuable causing significant body weight reduction between obese models, however human studies are needed

THE STUDY OF BUSINESS CENTERS IN THE ARABIAN GULF: RESIDENTIAL, OFFICES, AND COMMERCIAL BUILDINGS

The modern architecture of the Arabian Gulf has become an international icon after the completion of Burj Al Arab in 1999. Since then, many more modern buildings were built in order to host the numerous international companies residing or branching in the Arabian Gulf especially in Dubai.This article will examine few examples of the modern architecture the Arabian Gulf, some of many amazing projects were constructed, alongside a brief introduction, what challenges the architecture faces in the Arabian Gulf, and what’s the future seems like

The Effect Of Constraint Length And Interleaver On The Performance Of Turbo Code

This paper presents a class derived from convolutional code called turbo code. Theperformance of turbo code is investigated through examining the effect of different constraintlength, the effect of changing rate, and the effect of interleaver on the performance of turbocode with presence burst errors.The performance of turbo code is investigates through computer simulation, by usingMATLAB program.The simulation encoder is composed of two identical RSC component encoder with parallelconcatenated, separated by interleaver.The turbo code simulation results are showngraphically for different constraint length, in hard and soft decision. Also the simulationresults are shown for case with interleaver and without interleaver

Modelling a laser plasma accelerator driven free electron laser

Free-electron lasers (FEL) are the brightest, coherent sources of short wavelength radiation from the VUV into the x-ray. There is much research interest in reducing the cost and the size of FELs by utilising new accelerator techniques. Laser-plasma accelerator (LPA) are a promising accelerator for next generation compact FEL light sources with many potential advantages due to the high acceleration gradient and large peak currents they offer. The electron beams of a LPA typically have a smaller transverse emittance, a large energy spread and tend to be of shorter duration and higher current than conventional Radio Frequency (RF) accelerators. In this paper, a FEL driven by an electron beam from a typical LPA was simulated using the 3D FEL simulation code Puffin. It is shown that lowering the homogenous electron beam energy spread increases the radiation energy output in a short undulator and , as become less than the FEL, or Pierce parameter ($\rho$), then the peak radiation energy increases and the saturation length reduces significantly as expected

Gravitational collapse with tachyon field and barotropic fluid

A particular class of space-time, with a tachyon field, \phi, and a barotropic fluid constituting the matter content, is considered herein as a model for gravitational collapse. For simplicity, the tachyon potential is assumed to be of inverse square form i.e., V(\phi) \sim \phi^{-2}. Our purpose, by making use of the specific kinematical features of the tachyon, which are rather different from a standard scalar field, is to establish the several types of asymptotic behavior that our matter content induces. Employing a dynamical system analysis, complemented by a thorough numerical study, we find classical solutions corresponding to a naked singularity or a black hole formation. In particular, there is a subset where the fluid and tachyon participate in an interesting tracking behaviour, depending sensitively on the initial conditions for the energy densities of the tachyon field and barotropic fluid. Two other classes of solutions are present, corresponding respectively, to either a tachyon or a barotropic fluid regime. Which of these emerges as dominant, will depend on the choice of the barotropic parameter, \gamma. Furthermore, these collapsing scenarios both have as final state the formation of a black hole.Comment: 18 pages, 7 figures. v3: minor changes. Final version to appear in GR