1.Pre-transmetalation intermediates in the Suzuki-Miyaura reaction revealed: The missing link.
Thomas AA1, Denmark SE2. Science. 2016 Apr 15;352(6283):329-32. doi: 10.1126/science.aad6981.
Despite the widespread application of Suzuki-Miyaura cross-coupling to forge carbon-carbon bonds, the structure of the reactive intermediates underlying the key transmetalation step from the boron reagent to the palladium catalyst remains uncertain. Here we report the use of low-temperature rapid injection nuclear magnetic resonance spectroscopy and kinetic studies to generate, observe, and characterize these previously elusive complexes. Specifically, this work establishes the identity of three different species containing palladium-oxygen-boron linkages, a tricoordinate boronic acid complex, and two tetracoordinate boronate complexes with 2:1 and 1:1 stoichiometry with respect to palladium. All of these species transfer their boron-bearing aryl groups to a coordinatively unsaturated palladium center in the critical transmetalation event.
2.Nanoparticles and DNA - a powerful and growing functional combination in bionanotechnology.
Samanta A1, Medintz IL2. Nanoscale. 2016 Apr 15. [Epub ahead of print]
Functionally integrating DNA and other nucleic acids with nanoparticles in all their different physicochemical forms has produced a rich variety of composite nanomaterials which, in many cases, display unique or augmented properties due to the synergistic activity of both components. These capabilities, in turn, are attracting greater attention from various research communities in search of new nanoscale tools for diverse applications that include (bio)sensing, labeling, targeted imaging, cellular delivery, diagnostics, therapeutics, theranostics, bioelectronics, and biocomputing to name just a few amongst many others. Here, we review this vibrant and growing research area from the perspective of the materials themselves and their unique capabilities. Inorganic nanocrystals such as quantum dots or those made from gold or other (noble) metals along with metal oxides and carbon allotropes are desired as participants in these hybrid materials since they can provide distinctive optical, physical, magnetic, and electrochemical properties.
3.Comparison of different methods of cleaning and preparing occlusal fissure surface before placement of pit and fissure sealants: An in vivo study.
Hegde RJ1, Coutinho RC. J Indian Soc Pedod Prev Dent. 2016 Apr-Jun;34(2):111-4. doi: 10.4103/0970-4388.180403.
AIM: To evaluate an individual method of cleaning and preparing occlusal fissure surface before placement of pit and fissure sealant and to determine a method for better retention of the sealant.
4.Effects of Breast Shielding During Heart Imaging on DNA Double-Strand-Break Levels: A Prospective Randomized Controlled Trial.
Cheezum MK1, Redon CE1, Burrell AS1, Kaviratne AS1, Bindeman J1, Maeda D1, Balmakhtar H1, Pezel A1, Wisniewski P1, Delacruz P1, Nguyen B1, Bonner WM1, Villines TC1. Radiology. 2016 Apr 15:152301. [Epub ahead of print]
Purpose To examine the effect of breast shielding on blood lymphocyte deoxyribonucleic acid (DNA) double-strand-break levels resulting from in vivo radiation and ex vivo radiation at breast-tissue level, and the effect of breast shielding on image quality. Materials and Methods The study was approved by institutional review and commpliant with HIPAA guidelines. Adult women who underwent 64-section coronary computed tomographic (CT) angiography and who provided informed consent were prospectively randomized to the use (n = 50) or absence (n = 51) of bismuth breast shields. Peripheral blood samples were obtained before and 30 minutes after in vivo radiation during CT angiography to compare DNA double-strand-break levels by γ-H2AX immunofluorescence in blood lymphocytes. To estimate DNA double-strand-break induction at breast-tissue level, a blood sample was taped to the sternum for ex vivo radiation with or without shielding. Data were analyzed by linear regression and independent sample t tests.
