One-Step Synthesis of Triblock Copolymers via Simultaneous Reversible-Addition Fragmentation Chain Transfer (RAFT) and Ring-Opening Polymerization Using a Novel Difunctional Macro-RAFT Agent Based on Polyethylene Glycol

One-step synthesis of the triblock copolymers was carried out by reversible addition–fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) and ring-opening polymerization (ROP) of β-butyrolactone (BL) or ?-caprolactone (CL) using a novel difunctional macro-RAFT agent. For this purpose, primarily PEG-Br (polyethylene glycol bromine) was obtained by using 3-bromopropanoyl chloride and PEGs (polyethylene glycols) with different molecular weights. Then, macro-RAFT agent was synthesized by the reaction of potassium ethyl xanthogenate and PEG-Br. By using macro-RAFT agent, poly(MMA-b-EG-b-BL), and poly(MMA-b-EG-b-CL) triblock copolymers were synthesized by changing some polymerization conditions such as monomer/initiator concentration, polymerization time. The effect of the reaction conditions on the polydispersity and molecular weights were also investigated. The block lengths of the triblock copolymers were calculated by using ¹H-nuclear magnetic resonance (¹H-NMR) spectra. It was observed that the block length could be altered by varying the monomer and initiator concentrations. The characterization of the products were achieved using ¹H-NMR, Fourier-transform infrared spectroscopy (FTIR), gel-permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (γ) techniques.     

Path Integral Quantization of a Spinning Particle

Barut's classical model of the spinning particle having external dynamical variables x and p and internal dynamical variables and z is taken into account. The path integrations over holomorphic spinors and z are discussed. This quantization gives the kernel of the relativistic particles with higher spin as well as the Dirac electron. The Green's function of the spin-n/2 particle is obtained.     

Top-down, bottom-up, and side-to-side proteomics with virtual 2-D gels

Intact protein masses can be measured directly from immobilized pH gradient (IPG) isoelectric focusing (IEF) gels loaded with mammalian and prokaryotic samples, as demonstrated here with murine macrophage and Methanosarcina acetivorans cell lysates. Mass accuracy and resolution is improved by employing instruments which decouple the desorption event from mass measurement; e.g., quadrupole time-of-flight instruments. MALDI in-source dissociation (ISD) is discussed as a means to pursue top-down sequencing for protein identification. Methods have been developed to enzymatically digest all proteins in an IEF gel simultaneously, leaving the polyacrylamide gel attached to its polyester support. By retaining all gel pieces and their placement relative to one another, sample handling and tracking are minimized, and comparison to 2-D gel images is facilitated. MALDI-MS and MS/MS can then be performed directly from dried, matrix-treated IPG strips following whole-gel trypsin digestion, bottom-up methodology. Side-to-side proteomics, highlighting the link between virtual and classical 2-D gel electrophoresis, is introduced to describe a method whereby intact masses are measured from one side (the IEF gel), while proteins are identified based on analyses performed from the other side (the SDS-PAGE gel).     

Coulomb blockade of small Pd clusters

Single-electron tunneling through Au substrate-alkanethiol-Pd cluster-tip junctions is investigated with scanning tunneling spectroscopy. The measured I(V) curves reveal several characteristic features of the Coulomb blockade, namely, the presence of a Coulomb gap and a Coulomb staircase. By using the orthodox theory of single-electron tunneling, the capacitances and resistances of the double junction system as well as the fractional charge are extracted from the experimental data.     

On convergence,asymptotic behaviour and computational algorithm of generalized exponential integral functions arising in a radiative transfer

In this paper, we investigate uniform convergence of the generalized exponential integral functions (GEI) arising in the study of radiative transfer in a two-dimensional planar-medium and anisotropic scattering in a multidimensional medium. Using the uniform convergence, we study the properties and asymptotic behaviour of the GEI functions. We also give an efficient algorithm for the computations of the values of the GEI functions.     

Spectroscopic studies, antimicrobial activities, and crystal structure of N-[2-hydroxy-1-naphthylidene]3, 5-bis(trifluoromethyl)aniline

A new Schiff base compound has been synthesized by the reaction of 2-hydroxy-1-naphthaldehyde with 3,5-bis(trifluoromethyl)aniline.The title compound was characterized by elemental analysis, IR,¹H NMR,¹³C NMR, and UV–Visible techniques.Its UV–Vis spectra was examined in polar and nonpolar solvents and in acidic and basic media. The crystal structure of the compound showed the OH group to be ortho to the imine group. It crystallizes in the monoclinic space group P2₁ with a = 11.328(2), b = 6.125(1), c = 11.937(2) ?, V = 825.1(2) ?³, D _x = 1.543 g cm⁻³and Z = 2. An intramolecular O1- H⋯N1 [2.558(7) ?] hydrogen bond stabilizes the molecule. The compound has also been characterized by its antimicrobial activities. The ligand has been screened in vitro against the organisms Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Mycobacterium smegmatis CCM 2067, Bacillus cereus ATCC 7064, and Listeria monocytogenes ATCC 15313, the yeast cultures Candida albicans ATCC 10231, Kluyveromyces fragilis NRRL 2415, Rhodotorula rubra DSM 70403, Debaryomyces hansenii DSM 70238, and Hanseniaspora guilliermondii DSM 3432.     

Synthesis and crystal structure of bis[2-[N-(2-chlorophenyl)formimidayl]-1-naphtholato]-(6Cl)copper(II)

The title compound, bis[2-[N-(2-chlorophenyl)formimidayl]-1-naphtholato]-(6Cl) copper(II), [Cu(C₁₇H₁₁NOCl)₂] (1) was synthesized and its crystal structure was determined. The Compound 1 is monoclinic, space group P2 ₁/c with a = 9.146(3) Å, b = 18.724(3) Å, c = 16.230(2) Å, β = 96.46(1)°, V = 2761.8(11) ų, Z = 4, D _c = 1.503 g cm^?3, μ(Mo Kα) = 1.020 mm^?1, R = 0.0606 for 2361 reflections [I > 2σ(I)]. In the title compound, the Cu atom is coordinated by an N₂O₂ donor set from the imine-phenol ligand in a slightly distorted square planar coordination geometry, with the two phenolate O atoms being deprotonated. The Cu–O bond lengths are 1.878(4) and 1.889(4) Å, the Cu–N bond lengths are 1.980(5) and 1.985(5) Å. The angles O1–Cu–N1 and O2–Cu–N2 are 90.96(19) and 90.72(19)°, respectively.     

Computing robust basestock levels

This paper considers how to optimally set the basestock level for a single buffer when demand is uncertain, in a robust framework. We present a family of algorithms based on decomposition that scale well to problems with hundreds of time periods, and theoretical results on more general models.     

Classical and nonlinear buckling analyses of spherical sandwich shells

The buckling and initial postbuckling behavior of clamped shallow spherical sandwich shells with dissimilar face sheets under a uniform pressure is studied. The numerical results show that the buckling and initial post-buckling behavior of clamped shallow spherical sandwich shells with dissimilar face sheets is similar to that of the corresponding homogeneous shell.     

Cu (II) Chemosensor Based on a Fluorogenic Bodipy-Salophen Combination: Sensitivity and Selectivity Studies

A new fluorescent chemosensor (Bodipy-S) derived from Bodipy and Salophen was developed. After the characterization of all compounds, the behavior of the chemosensor Bodipy-S toward p, d and f block-metal ions was investigated by UV-vis and fluorescence spectroscopy. This chemosensor can selectively detect to Cu (II) in methanol-aqueous solution based on chelation enhanced fluorescence (CHEF) and it almost exhibit to a fluorescence quenching effect with 20-fold. The binding constant of the fluorophore was interpreted by using of the Stern-Volmer method and the complex stoichiometry was defined by using Job’s plot. Moreover, the effect of pH was performed by the fluorescence intensities of Bodipy-S in presence of Cu(II) ions. The chemosensor can be successfully used to the detection of Cu(II) in most areas.