475 research outputs found
d- Versus l-Glucose Conjugation: Mitochondrial Targeting of a Light-Activated Dual-Mode-of-Action Ruthenium-Based Anticancer Prodrug
Metals in Catalysis, Biomimetics & Inorganic Material
Selective Preparation of a Heteroleptic Cyclometallated Ruthenium Complex Capable of Undergoing Photosubstitution of a Bidentate Ligand
Cyclometallated ruthenium complexes typically exhibit redâshifted absorption bands and lower photolability compared to their polypyridyl analogues. They also have lower symmetry, which sometimes makes their synthesis challenging. In this work, the coordination of four N,S bidentate ligands, 3â(methylthio)propylamine (mtpa), 2â(methylthio)ethylamine (mtea), 2â(methylthio)ethylâ2âpyridine (mtep), and 2â(methylthio)methylpyridine (mtmp), to the cyclometallated precursor [Ru(bpy)(phpy)(CH3CN)2]+ (bpy=2,2âČâbipyridine, Hphpy=2âphenylpyridine) has been investigated, furnishing the corresponding heteroleptic complexes [Ru(bpy)(phpy)(N,S)]PF6 ([2]PF6â[5]PF6, respectively). The stereoselectivity of the synthesis strongly depended on the size of the ring formed by the Ruâcoordinated N,S ligand, with [2]PF6 and [4]PF6 being formed stereoselectively, but [3]PF6 and [5]PF6 being obtained as mixtures of inseparable isomers. The exact stereochemistry of the airâstable complex [4]PF6 was established by a combination of DFT, 2D NMR, and singleâcrystal Xâray crystallographic studies. Finally, [4]PF6 was found to be photosubstitutionally active under irradiation with green light in acetonitrile, which makes it the first cyclometallated ruthenium complex capable of undergoing selective photosubstitution of a bidentate ligand.Metals in Catalysis, Biomimetics & Inorganic Material
A Red-Light-Activated Ruthenium-Caged NAMPT Inhibitor Remains Phototoxic in Hypoxic Cancer Cells
Metals in Catalysis, Biomimetics & Inorganic Material
Why Primate Models Matter
Research involving nonhuman primates (NHPs) has played a vital role in many of the medical and scientific advances of the past century. NHPs are used because of their similarity to humans in physiology, neuroanatomy, reproduction, development, cognition, and social complexity â yet it is these very similarities that make the use of NHPs in biomedical research a considered decision. As primate researchers, we feel an obligation and responsibility to present the facts concerning why primates are used in various areas of biomedical research. Recent decisions in the United States, including the phasing out of chimpanzees in research by the National Institutes of Health and the pending closure of the New England Primate Research Center, illustrate to us the critical importance of conveying why continued research with primates is needed. Here we review key areas in biomedicine where primate models have been, and continue to be, essential for advancing fundamental knowledge in biomedical and biological research
Call to action: how can the US Ending the HIV Epidemic initiative succeed?
With more than 1·2 million people living with HIV in the USA, a complex epidemic across the large and diverse country, and a fragmented health-care system marked by widening health disparities, the US HIV epidemic requires sustained scientific and public health attention. The epidemic has been stubbornly persistent; high incidence densities have been sustained over decades and the epidemic is increasingly concentrated among racial, ethnic, and sexual and gender minority communities. This fact remains true despite extraordinary scientific advances in prevention, treatment, and careâadvances that have been led, to a substantial degree, by US-supported science and researchers. In this watershed year of 2021 and in the face of the COVID-19 pandemic, it is clear that the USA will not meet the stated goals of the National HIV/AIDS Strategy, particularly those goals relating to reductions in new infections, decreases in morbidity, and reductions in HIV stigma. The six papers in the Lancet Series on HIV in the USA have each examined the underlying causes of these challenges and laid out paths forward for an invigorated, sustained, and more equitable response to the US HIV epidemic than has been seen to date. The sciences of HIV surveillance, prevention, treatment, and implementation all suggest that the visionary goals of the Ending the HIV Epidemic initiative in the USA might be achievable. However, fundamental barriers and challenges need to be addressed and the research effort sustained if we are to succeed
The Milky Way Bulge: Observed properties and a comparison to external galaxies
The Milky Way bulge offers a unique opportunity to investigate in detail the
role that different processes such as dynamical instabilities, hierarchical
merging, and dissipational collapse may have played in the history of the
Galaxy formation and evolution based on its resolved stellar population
properties. Large observation programmes and surveys of the bulge are providing
for the first time a look into the global view of the Milky Way bulge that can
be compared with the bulges of other galaxies, and be used as a template for
detailed comparison with models. The Milky Way has been shown to have a
box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an
additional spheroidal component. In this review we summarise the global
chemical abundances, kinematics and structural properties that allow us to
disentangle these multiple components and provide constraints to understand
their origin. The investigation of both detailed and global properties of the
bulge now provide us with the opportunity to characterise the bulge as observed
in models, and to place the mixed component bulge scenario in the general
context of external galaxies. When writing this review, we considered the
perspectives of researchers working with the Milky Way and researchers working
with external galaxies. It is an attempt to approach both communities for a
fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen
E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure
Induction of a FourâWay Junction Structure in the DNA Palindromic Hexanucleotide 5âČâd(CGTACG)â3âČ by a Mononuclear Platinum Complex
Fourâway junctions (4WJs) are supramolecular DNA assemblies comprising four interacting DNA strands that in biology are involved in DNAâdamage repair. In this study, a new mononuclear platinum(II) complex 1 was prepared that is capable of driving the crystallization of the DNA oligomer 5âČâd(CGTACG)â3âČ specifically into a 4WJâlike motif. In the crystal structure of the 1âCGTACG adduct, the distortedâsquareâplanar platinum complex binds to the core of the 4WJâlike motif through ÏâÏ stacking and hydrogen bonding, without forming any platinumânitrogen coordination bonds. Our observations suggest that the specific molecular properties of the metal complex are crucially responsible for triggering the selective assembly of this peculiar DNA superstructure.Metals in Catalysis, Biomimetics & Inorganic Material
Induction of a four-way junction structure in the DNA palindromic hexanucleotide 5 '-d(CGTACG)-3 ' by a mononuclear platinum complex
Four-way junctions (4WJs) are supramolecular DNA assemblies comprising four interacting DNA strands that in biology are involved in DNA-damage repair. In this study, a new mononuclear platinum(II) complex 1 was prepared that is capable of driving the crystallization of the DNA oligomer 5 '-d(CGTACG)-3 ' specifically into a 4WJ-like motif. In the crystal structure of the 1-CGTACG adduct, the distorted-square-planar platinum complex binds to the core of the 4WJ-like motif through pi-pi stacking and hydrogen bonding, without forming any platinum-nitrogen coordination bonds. Our observations suggest that the specific molecular properties of the metal complex are crucially responsible for triggering the selective assembly of this peculiar DNA superstructure.Metals in Catalysis, Biomimetics & Inorganic Material
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
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