Preservation of Immunoreactivity in the Photolabeling of the B72.3 Human Antibody

Abstract— A mild and efficient method of linking a dihydroflavin to the C-17 carboxylic acid side chain of protochlorophyllide, without degradation of the sensitive E ring or loss of magnesium, is described. The appended dihydroflavin was shown to quench the fluorescence of protochlorophyllide. In contrast, a dihydronicotinamide moiety was unable to effect fluorescence quenching. The relevance of these findings to a possible mechanism of action of the enzyme protochlorophyllide reductase is discussed.     

Enantioselective synthesis of the 4-hydroxy buteneolide terminus of mucocin and related annonaceous acetogenins

The 4-hydroxy buteneolide terminus 3, applicable to mucocin 1 and related annonaceous acetogenins, was prepared in an expeditious manner from the selenocarbonate 2 via an intramolecular acyl radical cyclization followed by an enantioselective Lewis-acid catalyzed Keck-allylation reaction.     

Chemical synthesis and magnetic properties of HCP and FCC nickel nanoparticles

In this study, we successfully synthesized single-phase hexagonal closed packed (HCP) and face-centered cubic (FCC) nickel nanoparticles via reduction of nickel nitrate hexahydrate and nickel acetate tetrahydrate, respectively, in polyethylene glycol-200. Structural information of the as-synthesized nickel nanoparticles are studied by X-ray diffraction (XRD) as a function of the molar concentration of the nickel precursor. XRD results reveal that low concentrations of nickel precursor (0.005?M and below) favor the HCP, while high concentrations favor the mixture of HCP and FCC crystal structures. Particle size of HCP structure is found in the range of ～15?nm via transmission electron microscope analysis. Vibratory sample magnetometer is employed to study its magnetic behavior and the results reveal that FCC crystalline phase shows ferromagnetic nature with high saturation magnetization (M _s?～?39.6?emu?gm^?1) as compared to metastable HCP crystalline structure (M _s?～?2?emu?gm^?1). The surfactants bonding on the surface of nickel nanoparticles are studied.     

Preparation and characterization of 1,2,3‐triazole‐cured polymers from endcapped azides and alkynes

Fourteen commercial polyols have been characterized by GPC, NMR spectroscopy, and elemental analysis. From these, eight corresponding tosylates, six nitrate esters, seven mesylates, 13 alkynes, and 14 azides have been prepared and all these derivatives have been fully characterized. Five alkyne monomers and eight azide monomers were also prepared. Twelve alkynes and 13 azides (functionality 2–4) were combined in 1,3‐dipolar cycloaddition reactions under neat conditions to prepare triazole‐cured polymers, avoiding any heavy metal catalyst. Characterization by NMR spectroscopy, elemental analysis, and gel permeation chromatography indicated triazole polymers 14 , 22 , 23 , 28 , and 30 with degrees of polymerization of 17–28 to be the best candidates for future work. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 238–256, 2008     

Using discrete optimization algorithms to find minimum energy configurations of slender cantilever beams with non-convex energy functions

This paper deals with a new solution technique for approximately solving certain variational problems in elasticity by using discrete optimization techniques that were originally used in information theory. This allows us to easily and approximately solve large deformation buckling problems for slender cantilever beams (including post-buckling behavior) as well as problems where the strain energy function is non-convex.The core idea is to quantize or discretize the variables describing the possible configurations of the body. This, when combined with the fact that the variational problem has an inherent Markov structure allows us to use computationally efficient search techniques based on dynamic programming (equivalent to finding the shortest path in a weighted directed graph) to find optimal solutions within the quantized state space. The results can be used in two ways: (1) directly as a fast approximate solution to the variational problem (2) As a means for finding very good (nearly minimum energy) initial configurations for application of conventional minimization techniques, which might otherwise fail because of a poor starting configurations which are far from the global minimum. We demonstrate both these uses in the paper.     

Structure–property relationship of photoactive liquid crystalline polyethers containing benzylidene moiety

A series of main chain photoactive liquid crystalline polyethers, containing rigid bisbenzylidene photoactive mesogen and flexible methylene spacers, were synthesized by polycondensation of bisbenzylidene diols and dibromoalkanes. The polyethers were characterized with ¹H NMR, gel permeation chromatography (GPC), differential scanning calorimeter (DSC), thermo gravimetric analyzer (TGA), and polarized light optical microscopy. The individual and combined effects of spacer length and number of methoxy substituents on mesogenic and photoactive properties were investigated. Both first order and second order transition temperatures decreased with increased spacer length and the number of substituents. The combined effect of spacers and substituents drastically reduced the transition temperatures. All monomers and polymers showed mainly the smectic mesophase. In a few cases, nematic droplets along with the smectic phase were observed. The width of the liquid crystalline phase reduced with an increasing number of methoxy substituents on mesogenic unit. Variation of spacer length has a negligible effect on photocycloaddition. However, steric hinderance caused by the substituents decreased the photoactivity as the number of substituents increased. Total energies of crosslinked dimers calculated from modeling studies supported the above findings. Intermolecular photocycloaddition was also confirmed by photoviscosity measurement. The refractive index change was found to be in the range of 0.017–0.031. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2143–2155, 2009     

Transition metal complexes of pyrazole head 24-membered polyazamacrocyclic bimetal cores: synthesis, characterization, electrochemistry and spectral study

A series of new 24-membered macrocyclic Co^II, Ni^II, Cu^II and Zn^II complexes of the ligands L¹H₂ and L²H₂ were prepared by the non-template and template methods respectively. The ligand L¹H₂ was formed by the condensation of pyrazole-3,5-dicarbohydrazide and glyoxal and all attempts to isolate the ligand L²H₂ were unsuccessful. These, ligand and transition metal complexes were characterized on the basis of elemental analysis, IR, ¹HNMR, UV–Visible, magnetic susceptibility measurements, ESR, conductivity measurements, FAB-mass and thermal analysis. The redox behavior of metal ions in the polyazamacrocyclic ligand field is also studied. Electroreduction of carbon dioxide to carbon monoxide is mainly focused on using polydentate azamacrocyclic ligands with amine and imine functionalities, based on the electrochemical behavior of nickel (II) ion in the macrocyclic territory.     

Iodine as a versatile catalyst for the hydroalkylation of vinyl arenes with 1,3-diketones

The vinyl arenes undergo smooth hydroalkylation with 1,3-diketones in the presence of 10 mol % of iodine to afford phenethyl diketones and ketoesters in good yields in short reaction times. The use of inexpensive and readily available molecular iodine makes this method quite simple, more convenient and practical.     

Application of PET deprotection for orthogonal photocontrol of aqueous solution viscosity

Photorelease and photoisomerization of trans-cinnamic acid in aqueous CTAB solutions induces a bulk solution viscosity increase and decrease, respectively, triggered by orthogonal irradiation wavelengths.     

Anticonvulsant activity and toxicity evaluation of Cu(II) and Zn(II) metal complexes derived from triazole-quinoline ligands

A novel Cu(II) and Zn(II) complexes of triazolo-quinoline derivatives were synthesized by in situ method and were characterized by the spectro-analytical methods and their pharmacological properties were evaluated. The compound C3 has exhibited promising anticonvulsant activity towards the electroshock induced seizures in Wistar rats and possesses low toxicity, providing a high safety profile.