Effects of roughness on droplet apparent contact angles on a fiber

This paper reports on our investigation of the effects of surface roughness on the equilibrium shape and apparent contact angles of a droplet deposited on a fiber. In particular, the shape of a droplet on a roughened fiber is studied via the energy minimization method implemented in the surface evolver finite element code. Sinusoidal roughness varying in both the longitudinal and radial directions is considered in the simulations to study the effects of surface roughness on the most stable shape of a droplet on a fiber (corresponding a global minimum energy state). It is found that surface roughness delays droplet shape transition from a symmetric barrel to a clamshell or an asymmetric barrel profile. A phase diagram that includes the effects of fiber roughness on droplet configurations-symmetric barrel, clamshell, and asymmetric barrel-is presented for the first time. It is also found that droplet apparent contact angle tends to decrease on rough fibers. Likewise, roughness tends to increase the force required to detach a droplet from a fiber but the effect diminishes as droplet size increases relative to the size of surface roughness. The results presented in our study have been compared with experimental data or those from prior studies whenever possible, and good agreement has been observed

The effect of Aloe vera extract on humoral and cellular immune response in rabbit

Some plant polysaccharides are well known to possess immunostimulatory effects. Aloe vera possesses confirmed curative or healing actions. The aim of this study was to evaluate the effect of the administration of A. vera plant extract on cellular and humoral immune response in rabbits. 20 healthy male New Zealand white rabbits were randomly divided into five treatment groups: Groups consisted of: 1) control group (normal saline); 2) A. vera control; 3) vaccine control; 4) 50 mg A. vera extract + vaccine; 5) 150 mg A. vera extract + vaccine. The used vaccine was for myxomatosis. Blood samples were obtained at four time points: days 0, 7, 14 and 21 of the study. CD4+ and CD8+ lymphocytes frequency and serum immunoglobulin concentrations were evaluated. According to the results, oral administration of A. vera affected the composition of lymphocyte subsets and serum immunoglobulins positively. These findings demonstrated that A. vera may stimulate both cellular and humoral immune responses after immunization.Key words: Aloe vera, cellular and humoral immune, immunization, rabbits

Effect of fiber orientation on shape and stability of air-water interface on submerged superhydrophobic electrospun thin coatings

To better understand the role of fiber orientation on the stability of superhydrophobicelectrospun coatings under hydrostaticpressures, an integro-differential equation is developed from the balance of forces across the air–water interface between the fibers. This equation is solved numerically for a series of superhydrophobicelectrospun coatings comprised of random and orthogonal fiber orientations to obtain the exact 3D shape of the air–water interface as a function of hydrostaticpressure. More important, this information is used to predict the pressure at which the coatings start to transition from the Cassie state to the Wenzel state, i.e., the so-called critical transition pressure. Our results indicate that coatings composed of orthogonal fibers can withstand higher elevated hydrostaticpressures than those made up of randomly orientated fibers. Our results also prove that thin superhydrophobic coatings can better resist the elevated pressures. The modeling methodology presented here can be used to design nanofibrous superhydrophobic coatings for underwater applications

Bio ceramic Zirconia/Hydroxyapatite nano composite extracted from bovine bone

These days bone and joint problem is one of the serious health issues in the whole world, millions of people are suffered from it and number is increasing with an alarming rate. Annually, there are more than million surgeries getting done in the world just because of injuries to human hard tissue system. Recently in medical applications, synthetic Hydroxyapatite (HA) has been widely used as an important material because of excellent properties such as bio affinity and high osteogenic potential. HA, particles prevent the growth of cancer cells. Recently, natural hydroxyapatite bio ceramics are extracted by normal calcinations of some bio wastes. Biologically derived natural materials such as bovine bones, fish bones, oyster shells, corals and egg shells, they have converted into useful biomaterials. Moreover, extraction of HA from bio-waste is simple, economically and environmentally preferable. The mechanical Properties of HA is low in comparison with cortical bone. As a result, incorporation of resistant oxide phase has been resistant to optimize biocompatibility and improve mechanical properties of HA. Zirconia (ZrO2), is one of the best materials which can increase the HA properties. ZrO2 is a well known material which has high mechanical properties and greater strength, low toxicity and lower magnetic susceptibility in comparison with Ti and Titanium's alloys. In the present work, HA/ZrO2 bio ceramic were fabricated in various sintering conditions and nano particle size is achieved by milling technique. HA was derived from natural sources that chosen bovine bone. Effects of ZrO2 on the composites were investigated. Adding the additive resulted in the values of higher density. Density of the sintered samples was determined by using the Archimedes method and distilled water was used as the fluid medium. The phase formation of the sintered samples was analyzed by X-ray diffraction technique (XRD). The micro structural investigation of the samples was performed using a scanning electron microscope (SEM)

Lowest Order Constrained Variational calculation for Polarized Liquid 3He at Finite Temperature

We have investigated some of the thermodynamic properties of spin polarized liquid $^3\mathrm{He}$ at finite temperature using the lowest order constrained variational method. For this system, the free energy, entropy and pressure are calculated for different values of the density, temperature and polarization. We have also presented the dependence of specific heat, saturation density and incompressibility on the temperature and polarization.Comment: 17 pages, 7 figures. Int. J. Mod. Phys. B 27 (2008) in pres

Planar bichromatic minimum spanning trees

AbstractGiven a set S of n red and blue points in the plane, a planar bichromatic minimum spanning tree is the shortest possible spanning tree of S, such that every edge connects a red and a blue point, and no two edges intersect. We show that computing this tree is NP-hard in general. For points in convex position, a cubic-time algorithm can be easily designed using dynamic programming. We adapt such an algorithm for the special case where the number of red points (m) is much smaller than the number of blue points (n), resulting in an O(nm2) time algorithm. For the general case, we present a factor O(n) approximation algorithm that runs in O(nlognloglogn) time. Finally, we show that if the number of points in one color is bounded by a constant, the optimal tree can be computed in polynomial time

New combined PIC-MCC approach for fast simulation of a radio frequency discharge at low gas pressure

A new combined PIC-MCC approach is developed for accurate and fast simulation of a radio frequency discharge at low gas pressure and high density of plasma. Test calculations of transition between different modes of electron heating in a ccrf discharge in helium and argon show a good agreement with experimental data. We demonstrate high efficiency of the combined PIC-MCC algorithm, especially for the collisionless regime of electron heating.Comment: 6 paged, 8 figure

Entanglement study of the 1D Ising model with Added Dzyaloshinsky-Moriya interaction

We have studied occurrence of quantum phase transition in the one-dimensional spin-1/2 Ising model with added Dzyaloshinsky-Moriya (DM) interaction from bi- partite and multi-partite entanglement point of view. Using exact numerical solutions, we are able to study such systems up to 24 qubits. The minimum of the entanglement ratio R $\equiv$ \tau 2/\tau 1 < 1, as a novel estimator of QPT, has been used to detect QPT and our calculations have shown that its minimum took place at the critical point. We have also shown both the global-entanglement (GE) and multipartite entanglement (ME) are maximal at the critical point for the Ising chain with added DM interaction. Using matrix product state approach, we have calculated the tangle and concurrence of the model and it is able to capture and confirm our numerical experiment result. Lack of inversion symmetry in the presence of DM interaction stimulated us to study entanglement of three qubits in symmetric and antisymmetric way which brings some surprising results.Comment: 18 pages, 9 figures, submitte

Selective Adsorption and Chiral Amplification of Amino Acids in Vermiculite Clay -Implications for the origin of biochirality

Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH3Cl ions, forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. N-propyl NH3Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L- and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic organic molecules in clay inter-layers is known to produce Layer-by-Layer or Langmuir-Blodgett films. Moreover atomistic simulations show that self-organization of organic species in clay interlayers is important. These non-centrosymmetric, chirally active nanofilms may cause clays to act subsequently as chiral amplifiers, concentrating organic material from dilute solution and having different adsorption energetics for D- and L-enantiomers. The additional role of clays in RNA oligimerization already postulated by Ferris and others, together with the need for the organization of amphiphilic molecules and lipids noted by Szostak and others, suggests that such chiral separation by clays in lagoonal environments at normal biological temperatures might also have played a significant role in the origin of biochirality.Comment: 17 Pages, 2 Figures, 4 Table