Economic models for Dirac neutrinos in grand unified theories

It is shown that dimension five non-renormalizable interactions can produce light Dirac neutrinos in an extension of the minimal SU(5) GUT containing additional SU(5) singlets and global U(1) symmetries.     

Stabilization of ortho-quinone methides by a bis(sulfonium ylide) derived from 2,5-dihydroxy-[1,4]benzoquinone

The zwitterionic intermediates (2a) in the oxidation of ortho-alkylphenols (1) and bis(sulfonium ylide) 3 form reasonably stable 2:1-complexes (4), in which the ortho-quinone methide (oQM) moieties are not present in quinoid form with the exocyclic in-plane methylene group, but as zwitterionic, aromatic conformer having an out-of-plane exocyclic methylene group. The complex 7 derived from the α-tocopherol model compound PMC (5) was comprehensively characterized. As exemplarily demonstrated, the adducts can be advantageously employed in organic synthesis as ‘stabilized oQMs’.     

HPMA copolymer-doxorubicin-gadolinium conjugates: synthesis, characterization, and in vitro evaluation

This study describes the synthesis, characterization, and in vitro evaluation of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-gadolinium (Gd)-doxorubicin (Dox) conjugates. Copolymers of HPMA were derivatized to incorporate side chains for Gd chelation and Dox conjugation. The conjugates were characterized by their side chain contents, T(1) relaxivity (r(1)), stability, and in vitro cytotoxicity. High stability and relaxivity of these conjugates coupled with low toxicity show their potential for monitoring the in vivo fate of HPMA-based drug delivery systems by magnetic resonance imaging techniques.     

Reduction of tertiary phosphine oxides with DIBAL-H

The reduction of tertiary phosphine oxides (TPOs) and sulfides with diisobutylaluminum hydride (DIBAL-H) has been studied in detail. An extensive solvent screen has revealed that hindered aliphatic ethers, such as MTBE, are optimum for this reaction at ambient temperature. Many TPOs undergo considerable reduction at ambient temperature and then stall due to inhibition. 31P and 13C NMR studies using isotopically labeled substrates as well as competition studies have revealed that the source of this inhibition is tetraisobutyldialuminoxane (TIBAO), which builds up as the reaction proceeds. TIBAO selectively coordinates the TPO starting material, preventing further reduction. Several strategies have been found to circumvent this inhibition and obtain full conversion with this extremely inexpensive reducing agent for the first time. Practical reduction protocols for these critical targets have been developed.     

Solitary wave solutions of coupled boussinesq equation

This article presents the general case‐study of our previous works regarding generalized Boussinesq equations [17, 18, 19], that focus on application of various subordinate methods where are applied to construct more general exact solutions of the coupled Boussinesq equations. In this article, the ‐expansion method is applied on coupled Boussinesq equations. Our work is motivated by the fact that the ‐expansion method provides not only more general forms of solutions but also periodic, solitary waves, and rational solutions. The method appears to be easier and faster by means of a symbolic manipulation program. © 2016 Wiley Periodicals, Inc. Complexity 21: 151–155, 2016     

Smart Approach for In Situ One‐Step Encapsulation and Controlled Delivery of a Chemotherapeutic Drug using Metal–Organic Framework–Drug Composites in Aqueous Media

Controlled release of an anticancer drug, doxorubicin (dox), from metal–organic framework (MOF)–drug composites is demonstrated under different external stimuli. 1,3,5‐Benzenetricarboxylic acid (H₃BTC) is used as an organic ligand, and iron acetate and zinc nitrate are used as metal sources to synthesize Fe–BTC and Zn–BTC MOFs, which are known to be biocompatible. The in situ formation of MOF–drug composites demonstrates high drug loading capacity compared to conventional methods. The present methodology is devoid of any extra steps for loading the drug after synthesis. Moreover, the drug loading is also independent of pore size of the MOF as the drug molecules are embedded inside the MOF during their in situ formation. The drug release was monitored under external stimuli including change to acidic pH and the presence of biocompatible liposomes for a period of more than 72 h. Steady‐state fluorescence spectroscopy is used to monitor the drug release as a function of time and confocal laser scanning microscopy is used to unravel the post‐release fate of doxorubicin in the presence of liposomes. It is found that drug release rate is higher for the Zn–BTC–dox composite than for the Fe–BTC–dox composite. This is attributed to the stronger binding between dox and Fe‐BTC than that between dox and Zn–BTC. This study highlights a novel approach for the preparation of MOF–drug composites in an aqueous medium for future biomedical applications.     

Tandem Pd(II)-catalyzed vinyl ether exchange-Claisen rearrangement as a facile approach to gamma,delta-unsaturated aldehydes

A sequential allyl vinyl ether formation-Claisen rearrangement process catalyzed by a palladium(II)-phenanthroline complex is reported. The effects of allylic alcohol structure, type of vinylating agent, and palladium catalysts are discussed. This method provides a convenient approach to gamma,delta-unsaturated aldehydes under mild conditions that avoid the use of toxic Hg(II) catalysts. The new methodology has been successfully demonstrated on the kilogram scale.     

Dynamics of solvent and rotational relaxation of coumarin-153 in room-temperature ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate confined in poly(oxyethylene glycol) ethers containing micelles

We have investigated solvent and rotational relaxation of coumarin 153 (C-153) in room-temperature ionic liquid (RTILs) 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF(4)]) and the ionic liquid confined in alkyl poly(oxyethylene glycol) ethers containing micelles. We have used octaethylene glycol monotetradecyl ether (C(14)E(8)) and octaethylene glycol monododecyl ether (C(12)E(8)) as surfactants. In the [bmim][BF(4)]-C(14)E(8) micelle, we have observed only a 22% increase in solvation time compared to neat [bmim][BF(4)], whereas in the [bmim][BF(4)]-C(12)E(8) system, we have observed approximately 57% increase in average solvation time due to micelle formation. However, the slowing down in solvation time on going from neat RTIL to RTIL-confined micelles is much smaller compared to that on going from water to water confined micellar aggregates. The 22-57% increase in solvation time is attributed to the slowing down of collective motions of cations and anions in micelles. The rotational relaxation times become faster in both the micelles compare to neat [bmim][BF(4)].     

Shape changing and accelerating solitons in the integrable variable mass sine-gordon model

The sine-Gordon model with a variable mass (VMSG) appears in many physical systems, ranging from the current through a nonuniform Josephson junction to DNA-promoter dynamics. Such models are usually nonintegrable with solutions found numerically or perturbatively. We construct a class of VMSG models, integrable at both the classical and the quantum levels with exact soliton solutions, which can accelerate and change their shape, width, and amplitude simulating realistic inhomogeneous systems at certain limits.