1,612 research outputs found
Selective Hydrogenation and Transfer Hydrogenation for Post-Functional Synthesis of Trifluoromethylphenyl Diazirine Derivatives for Photoaffinity Labeling
Elucidation of protein functions on the basis of structure–activity relationships can reveal the mechanisms of homeostasis functions in life and is one of the greatest interests of scientists. In the human body, many proteins are activated and/or inactivated by ligands to maintain homeostasis. Understanding the mechanism of molecular interactions between small bioactive ligands and proteins is an important step in rational drug design and discovery. ! Photoaffinity labeling, which is one of the most familiar approaches for chemical biology analysis, was initiated using diazocarbonyl derivatives in 1962 (Singh et al., 1962). Many researchers have subsequently tried to establish alternative approaches for the direct identification of target proteins for the bioactive small ligands. These approaches are based on the affinity between the ligand and the target protein (Figure 1). Several reviews are published for the recent applications of photoaffinity labeling (Tomohiro et al., 2005; Hashimoto & Hatanaka, 2008). To archive photoaffinity labeling, researchers have to prepare photoaffinity labeling ligands. The native ligands must be modified by photoreactive compounds (photophores) by organic synthesi
Measurement of the mass of the τ lepton
The mass of the τ lepton has been measured at the Beijing Electron-Positron Collider using the Beijing Spectrometer. A search near threshold for e^+e^-→τ^+τ^- was performed. Candidate events were identified by requiring that one τ decay via τ→eνν¯, and the other via τ→μνν¯. The mass value, obtained from a fit to the energy dependence of the τ^+τ^- cross section, is m_τ=1776.9_(-0.5)^(+0.4)±0.2 MeV
Radiative and Semileptonic B Decays Involving Higher K-Resonances in the Final States
We study the radiative and semileptonic B decays involving a spin-
resonant with parity for and for
in the final state. Using the large energy effective theory (LEET)
techniques, we formulate transition form factors in the large
recoil region in terms of two independent LEET functions
and , the values of
which at zero momentum transfer are estimated in the BSW model. According to
the QCD counting rules, exhibit a dipole
dependence in . We predict the decay rates for ,
and . The
branching fractions for these decays with higher -resonances in the final
state are suppressed due to the smaller phase spaces and the smaller values of
. Furthermore, if the spin of
becomes larger, the branching fractions will be further suppressed due to the
smaller Clebsch-Gordan coefficients defined by the polarization tensors of the
. We also calculate the forward backward asymmetry of the decay, for which the zero is highly insensitive to the
-resonances in the LEET parametrization.Comment: 27 pages, 4 figures, 7 tables;contents and figures corrected, title
and references revise
Extranatural Inflation
We present a new model of inflation in which the inflaton is the extra
component of a gauge field in a 5d theory compactified on a circle. The chief
merit of this model is that the potential comes only from non-local effects so
that its flatness is not spoiled by higher dimensional operators or quantum
gravity corrections. The model predicts a red spectrum (n ~ 0.96) and a
significant production of gravitational waves (r ~ 0.11). We also comment on
the relevance of this idea to quintessence.Comment: 4 pages. Minor corrections and references added. Accepted for PR
A model of CP Violation from Extra Dimension
We construct a realistic model of CP violation in which CP is broken in the
process of dimensional reduction and orbifold compactification from a five
dimensional theories with gauge symmetry. CP
violation is a result of the Hosotani type gauge configuration in the higher
dimension.Comment: 5 page
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