Working group report: Flavor physics and model building

This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently.     

Synthesis of arenediynes via the vinylidenecarbene-acetylene rearrangement

A convenient method for the two-step synthesis of arenediynes from 1,2-arenedialdehydes is reported. Dibromomethylenation of dialdehydes under Corey-Fuchs conditions (CBr₄, Ph₃P, Zn) provides the tetrabromides in excellent yields. Treatment of the tetrabromides with n-BuLi or LDA affords 3,4-unsaturated 1,5-diynes, the key structural moiety present in several naturally occurring antitumour antibiotics, in varying yields. The key intermediates in these transformations appear to be vinylidenecarbenes or carbenoids, generated in situ via metal-halogen exchange and elimination.     

Vinyl polymerization of acrylamide initiated by Thallium(III) ions in solution

Kinetics of polymerization of acrylamide initiated by Thallium(III) perchlorate was investigated in aqueous perchloric acid medium in the temperature range of 55–70°C. The rates of polymerization were measured varying the concentration of the monomer, initiator, and perchloric acid. The rate of polymerization was found to increase with increase of temperature, monomer concentration, initiator concentration, and perchloric acid concentration. The effect of additives like different solvents, surfactants, and retarders on the rate of polymerization was studied. Molecular weights of the polymer were determined by viscometry. The chain transfer constants for the monomer (C_M) and that for the solvent dioxan (C_s) were calculated to be 7.33 × 10^?3 and 6.66 × 10^?3, respectively. From the Arrhenius plot, the overall activation energy (E_a) was calculated to be 10.68 kcal/mol. The energy of initiation was calculated to be 12.36 kcal/mol. Depending on the results obtained, a suitable reaction mechanism has been suggested and a rate equation has been derived.     

Polyhydroxy pregnanes from Dregea volubilis

Three new polyhydroxy pregnanes named dregealol (1), volubilogenone (2) and volubilol (3) were isolated from the flowers of Dregea volubilis, and their structures elucidated from extensive 2D NMR analysis. The structure of volubilol (3) was confirmed by X-ray crystallographic studies. The known pregnane derivatives drevogenin D, iso-drevogenin P and 17α-marsdenin were also isolated.     

Cation Exchange and Sorption Properties of TIN(IV) Phosphate

The ion exchange and sorption properties of crystalline Tin bis(monohydrogen orthophosphate) monohydrate of composition Sn(HPO(4))(2).H(2)O were studied in an aqueous solution of KCl over the temperature range 300-320 K, varying the pH and metal ion concentration in the solution. The data were explained on the basis of the law of chemical equilibrium. The metal ion sorption data were fitted to the Langmuir adsorption equation to evaluate the Langmuir parameters. The extent of adsorption was found to increase with an increase in temperature and metal ion concentration in the selectivity order Cu(2+)>Co(2+)>Ni(2+). The Langmuir parameters were used to calculate the thermodynamic functions like standard entropy, enthalpy, and free energy changes during the process of sorption. Copyright 2000 Academic Press.     

A comparative study on textural characterization: cation-exchange and sorption properties of crystalline alpha-zirconium(IV), tin(IV), and titanium(IV) phosphates

Tetravalent metal phosphates (M=Zr, Ti, and Sn) were prepared and characterized by XRD, surface properties, and TG-DTA. The cation exchange and sorption behavior of these metal phosphates toward transition metal ions such as Cu(2+), Co(2+), and Ni(2+) have been studied comparatively as a function of temperature and concentration. The adsorption process was found to increases with increase in temperature and concentration. The selectivity order for alpha-titanium and alpha-tin phosphates is Cu(2+)>Co(2+)>Ni(2+), whereas for alpha-zirconium phosphate it is Cu(2+)>Ni(2+)>Co(2+). The ion exchange capacity of alpha-titanium phosphate is greater than those of other phosphates, which is explained on the basis of the surface behavior, disorderness of the system, degree of hydrolysis of incoming guest adsorbate metal ions, and structural steric hindrance of the exchangers during adsorption and sorption. The distribution coefficient, Gibbs free energy, enthalpy, and entropy values indicate that the ion-exchange processes are spontaneous.     

Synthesis and applications of a novel supramolecular polymer network with multiple H‐bonded melamine pendants and uracil crosslinkers

A conjugated main‐chain copolymer ( PBT ) consisting of bithiazole, dithieno[3,2‐b:2′,3′‐d]pyrroles (DTP), and pendent melamine units was synthesized by Stille polymerization, which can be hydrogen‐bonded (H‐bonded) with proper molar amounts of bi‐functional π‐conjugated crosslinker F (i.e., two uracil motifs covalently attached to a fluorene core through triple bonds symmetrically) to develop a novel supramolecular polymer network ( PBT/F ). The effects of multiple H‐bonds on light harvesting capabilities, HOMO levels, and photovoltaic properties of polymer PBT and H‐bonded polymer network PBT/F are investigated. The formation of supramolecular polymer network ( PBT/F ) between PBT and F was confirmed by FTIR and XRD measurements. Because of the stronger light absorption, lower HOMO level, and higher crystallinity of H‐bonded polymer network PBT/F , the solar cell device containing PBT/F showed better photovoltaic properties than that containing polymer PBT . The preliminary results show that the solar cell device containing 1:1 weight ratio of PBT/F and [6,6]‐phenyl C₇₁ butyric acid methyl ester (PC₇₁BM) offers the best power conversion efficiency (PCE) value of 0.86% with a short‐circuit current density (J_sc) of 4.97 mA/cm², an open circuit voltage (V_oc) of 0.55 V, and a fill factor (FF) of 31.5%. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

SH-waves in viscoelastic heterogeneous layer over half-space with self-weight

The effect of gravity, heterogeneity and internal friction on propagation of SH-waves (horizontally polarised shear waves) in viscoelastic layer over a half-space has been studied. Using the method of separation of variables, dispersion equation has been obtained and used to recover the damped velocity of SH-waves. Both the real and imaginary parts of dispersion equation are in well agreement with the classical Love wave equation. It has been observed that heterogeneity of the medium affects the velocity profile of SH-wave significantly. Some other peculiarities have been observed and discussed in our study.     

Spectroscopic techniques in medicine: The future of diagnostics

Spectroscopic techniques have been finding increasing applications in the field of biomedicine especially in the field of disease diagnosis and monitoring in spite of the rapid emergence of several molecular biology based techniques. The significance of spectroscopy techniques and the possibility of using some of the underutilized regions of the electromagnetic radiations are discussed in this review. While previous reviews have already dealt with the potential of Fourier transform infrared spectroscopy-based (FTIR) techniques for clinical applications, the present review addresses the lacunae of the techniques along with its future trends that may make it a technique routinely applied in clinical settings.     

Task-specific ionic liquid tetraalkylammonium hydrogen phthalate as an extractant for U(VI) extraction from aqueous media

In this paper a quaternary ammonium based room temperature ionic liquid (IL) trioctylmethylammonium hydrogen phthalate has been reported as promising extractant for separation of U(VI) from other metal ions from aqueous media. The IL was synthesized via metathesis route and characterized using various techniques such as hydrogen nuclear magnetic resonance, electron spray ionization mass spectrometry and infra red etc. The newly synthesized IL was evaluated for extraction of U(VI), Th(IV), La(III), Y(III), Nd(III) and Fe(III) from aqueous solutions and follow the order: U(VI) > Th(IV) > Fe(III) > Y(III) >> Nd(III) ~ La(III).