Design of a novel fibronectin-mimetic peptide-amphiphile for functionalized biomaterials

The interaction of the alpha5beta1 integrin with its ligand, fibronectin, supports numerous adhesive functions and has an important role in health and disease. In recent years, there has been a considerable effort in designing fibronectin-mimetic peptides to target the integrin. However, to date, the therapeutic use of these peptides has been limited, as they cannot accurately mimic fibronectin's binding affinity for alpha5beta1. A peptide-amphiphile (PR_b) was synthesized with a peptide headgroup composed of four building blocks: a spacer; RGDSP, the primary recognition site for alpha5beta1; PHSRN, the synergy binding site; and a linker. The linker was designed to mimic two important criteria: the distance and the hydrophobicity/hydrophilicity between PHSRN and RGD in fibronectin. Human umbilical vein endothelial cells were seeded on different substrates and evaluated in terms of adhesion, spreading, specificity, cytoskeleton organization, focal adhesions, and secretion of extracellular fibronectin. This peptide was shown to perform comparably to fibronectin, indicating that a biomimetic approach can result in the design of novel peptides with therapeutic potential for biomaterial functionalization.     

Directional change of magnetic easy axis of arrays of cobalt nanowires: Role of non-dipolar magnetostatic interaction

Room temperature magnetization of two dimensional (2D) arrays of cobalt nanowires (NWs) having diameter 50 and 150 nm prepared by electrodeposition are studied in details. Diffraction patterns of the NWs reveal that the crystallites of the NWs become more textured on decreasing their diameter. Magnetic hysteresis loop measurements show the magnetic easy axis changes its direction from axial to perpendicular direction of NWs on increasing the length of the NWs. The magnetostatic interaction among the NWs, known as the key factor in defining the easy direction is found not to be dipolar at all the circumstances. An aspect ratio (length/diameter of NWs) dependence of the non-dipolar interaction in 150 nm NWs is evident from the static magnetization as well as from ferromagnetic resonance (FMR) measurements.     

Dose Dependencies and Biocompatibility of Renal Clearable Gold Nanoparticles: From Mice to Non‐human Primates

While dose dependencies in pharmacokinetics and clearance are often observed in clinically used small molecules, very few studies have been dedicated to the understandings of potential dose‐dependent in vivo transport of nanomedicines. Here we report that the pharmacokinetics and clearance of renal clearable gold nanoparticles (GS‐AuNPs) are strongly dose‐dependent once injection doses are above 15 mg kg^?1: high dose expedited the renal excretion and shortened the blood retention. As a result, the no‐observed‐adverse‐effect‐level (NOAEL) of GS‐AuNPs was >1000 mg kg^?1 in CD‐1 mice. The efficient renal clearance and high compatibility can be translated to the non‐human primates: no adverse effects were observed within 90 days after intravenous injection of 250 mg kg^?1 GS‐AuNPs. These fundamental understandings of dose effect on the in vivo transport of ultrasmall AuNPs open up a pathway to maximize their biomedical potentials and minimize their toxicity in the future clinical translation.     

Alternating copolymer of styrene–acrylonitrile obtained with vanadium-based complex catalyst in presence of monomers

Vanadium-based catalyst complexes prepared in the presence of monomers have been used for the copolymerization of styrene and acrylonitrile. VOCl₃–Al(i-C₄H₉)₃ catalyst system seems to yield an alternating copolymer. The copolymers are easily soluble in DMF and have low softening points.     

Scaling-up experience of actinides partitioning from intermediate level high salted alkaline waste streams of Purex process using Versatic-10 extractant

Partitioning of minor alpha-emitting actinides, especially U, Pu and Am from medium active alkaline waste is possible from intermediate level liquid wastes (ILLW) produced during spent fuel reprocessing following Purex process. This paper deals with the efficient removal of alpha-activity from ILLW by solvent extraction process. Counter current batch extraction with O/A ratio 2:1 as well as multistage mixer settler has demonstrated that most of the alpha-activity was removed from the alkaline effluents using 20% Versatic-10 (V-10) in dodecane after giving 3 to 4 contacts, thus converting alkaline waste as non-alpha waste. Under the optimum conditions (pH 9.0-9.5 and VA-10), both Pu(IV) and Am(III) are highly extractable whereas U(VI) is relatively poorly extracted. To assess the applicability of this process for regular treatment of the waste, a feasibility study on pilot plant scale using six stage mixer settler was operated to treat the ILLW. The results indicated that almost >99.90% alpha-emitting actinides are removed. Dilute nitric acid (0.5M HNO₃) served as the most efficient strippant for all these actinides. This facilitate an easy regeneration of the extractant which can be recycled. This method is useful in obtaining alpha-free wastes and had positive impact on ease and safety aspects during subsequent waste treatment and long term storage.     

Control of harmonic generation by initial-state preparation

A procedure to control harmonic generation is proposed using initial state control. We show that an initial molecular state can be prepared before shining a strong laser pulse to maximize the output harmonic generation. We demonstrate the method by maximizing emission for the sixth harmonic on a given initial IR pulse in a model H₂⁺ system using five initial vibrational states.     

Polymerization of styrene with chromium acetylacetonate–triisobutylaluminum catalyst system

Styrene is polymerized with chromium acetylacetonate–triisobutylaluminum catalyst at 40°C in a benzene medium. At the stoichiometric ratio of Al/Cr of 4, the activity for polymerization was found to be maximum. Further, the kinetic studies were carried out at this ratio of Al/Cr of maximum activity. The kinetics of polymerization and the total activation energy around 10.00 kcal/mole suggest a coordinate anionic mechanism.