The phosphine-catalyzed [4 + 2] annulations between allenoates and electron-poor trifluoromethyl ketones or N-tosylbenzaldimine dipolarophiles have been investigated in continuum solvation using density functional theory (DFT) calculations. The detailed reaction mechanisms as well as the high cis-diastereoselectivities of the reactions have been firstly clarified. Our calculated results reveal ...

Lanthanide DOTA-tetraglycinate (LnDOTA-(gly)₄⁻) complexes contain four magnetically equivalent amide protons that exchange with protons of bulk water. The rate of this base catalyzed exchange process has been measured using chemical exchange saturation transfer (CEST) NMR techniques as a function of solution pH for various paramagnetic LnDOTA-(gly)₄⁻ complexes to evaluate the effects of lanthan...

Introduction: Many study shown the effectiveness dose enhancement with gold nanoparticles (GNPs), especially with low-energy x-rays. Recently, proton beam radiation therapy (PBRT) has attention as a treatment for tumors. The advantage in PBRT, which releases high dose at the controllable Bragg peak position that localized for Au target and the released dose increased in depth....

The measurement of proton gyromagnetic ratio }'p' has been the object of an intensive experimental program for several decades [l]-[3]. The gyromagnetic ratio of the proton is defined as a resonance frequency «p divided by a magnetic field Bo [4], when a spherical water sample at 25°C is applied by a magnetic field. The ?P' for a defined pure water sample is somewhat difficult to measure becaus...

The electron flow in photosynthesis from H20 to NADP® is driven by two photoactive molecules, chlorophyll-an and chlorophyll-ai. These two chlorophyll molecules are arranged in series within a chain of elec­ tron carriers. The chain is imbedded in the membrane of the thylakoids. The electron carrier plastoquinone is engaged between the two photoactive chlorophyll mole­ cules. During the transfe...

Introduction: The proton beam produced in particle accelerators has an appropriate therapeutic potential. In this research, proton therapy of breast cancer is simulated using the MCNPX code in a MIRD phantom, also the contribution of scattered neutron dose during the proton therapy were calculated for the Heart, Lung and Liver.   Materials and Methods: For si...