In this study, the high-resolution ultrasonic spectroscopy (HR-US) technique was applied to examine interpolyelectrolyte neutralization. The mentioned method tested on example of complexation between poly(allylammonium) cations and poly(acrylate) anions in aqueous solutions at pH = 7. It confirmed by HR-US that type titration (stepwise or abrupt), direction titration, background salt affect out...

in this study, microspheres containing estradiol valerate were prepared by solvent evaporation method using poly (glycolide-co-lactide) (plga 50:50) and poly (lactide). the effect of different process variables such as polymer type, drugpolymer ratio, stirring rate, volume of internal phase and temperature of external phase on the morphology, particle size distribution, encapsulation efficiency...

peripheral nerve injuries caused by traffic accidents, resections of tumors or iatrogenic side effects of the surgeries are few of the most common form of trauma occurring with up to 500,000 cases each year in iran. conventional strategies including nerve coaptation, and the application of autografts, allografts and xenografts are restricted due to the limited availability of donors, immune-rej...

objective(s): three-dimensional structures such as nanofibrous scaffolds are being used in biomedical engineering as well as provide a site for cells to attach and proliferate leading to tissue formation. in the present study, poly(vinyl pyrrolidone) (pvp)/ poly(vinyl alcohol)(pva) hybrid nanofibrous scaffold was synthesized by electrospinning. materials and methods: the effect of adding nano h...

To understand the material characteristics of singleand poly-crystals of pure copper, the respective relationships between crystallographic orientations and microstructures, and the bending and mechanical properties were examined. And texture distribution is also analyzed. A bending test is performed in a SEM apparatus and while its behaviors are observed in situ. Furthermore, some analytical r...

Three recent papers reveal a fascinating link between pol II termination and ribonucleolytic decay of the nascent transcript by a 5'-3' exonuclease (yeast Rat1 and human Xrn2). The exonuclease travels with pol II and gains access to the nascent RNA after endonucleolytic cleavage at the poly(A) site or at a second cotranscriptional cleavage site (CoTC). It is then thought to track in a 5'-3' dir...

Based on a semiflexible trisilacyclohexane framework series of directed, tridentate Lewis acids were synthesized by hydrosilylation using various (chloro)methylsilanes. The axial alignment the three electron deficient functions in one spatial direction allows creating poly-Lewis with chalice-like cavities. obtained quantitative yields and characterized multinuclear NMR spectroscopy, CHN analysi...

Two DNA polymerase isoenzymes, called DpA and DpB on the basis of their elution order from DEAE cellulose, were purified to homogeneity from the thermo-acidophilic eubacterium Bacillus acidocaldarius. The enzymes are weakly acidophilic proteins constituted by a single subunit of 117 and 103 kDa respectively. DpA and DpB differ in thermostability, in thermophilicity, in sensitivity to assay cond...

Al2O3-YAG-ZrO2 eutectic ceramic rods of 5 mm in diameter were grown by micro-pulling down technique. The seeding and the solidification rate affect microstructure, morphology, crystallography, thermal stress solidified ceramics. ternary through zirconia (111) seed had inhomogeneous irregular cellular microstructures. At stationary stable regime, microstructure spacing (λ) depends on pulling (v)...

High-resolution mass spectrometry (HRMS) continues to play an important role in the compositional characterization of larger organic molecules. In the field of polymer characterization, however, the application of HRMS has made only slow progress because of lower compatibility between matrix-assisted laser desorption/ionization (MALDI) and ultrahigh-resolution Fourier transform ion cyclotron re...