SciCombinator

Discover the most talked about and latest scientific content & concepts.

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After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no experimental evidence for these nanostructures, in spite of the progress made in theoretical investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40(-) with an extremely low electron-binding energy. Theoretical calculations show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40(-) with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calculated to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized σ and π bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.

Concepts: Scientific method, Electron, Carbon, Philosophy of science, Graphite, Bond, Fullerene, Truncated icosahedron

31

Photosynthesis powers life on our planet. The basic photosynthetic architecture consists of antenna complexes that harvest solar energy and reaction centres that convert the energy into stable separated charge. In oxygenic photosynthesis, the initial charge separation occurs in the photosystem II reaction centre, the only known natural enzyme that uses solar energy to split water. Both energy transfer and charge separation in photosynthesis are rapid events with high quantum efficiencies. In recent nonlinear spectroscopic experiments, long-lived coherences have been observed in photosynthetic antenna complexes, and theoretical work suggests that they reflect underlying electronic-vibrational resonances, which may play a functional role in enhancing energy transfer. Here, we report the observation of coherent dynamics persisting on a picosecond timescale at 77 K in the photosystem II reaction centre using two-dimensional electronic spectroscopy. Supporting simulations suggest that the coherences are of a mixed electronic-vibrational (vibronic) nature and may enhance the rate of charge separation in oxygenic photosynthesis.

Concepts: Photosynthesis, Scientific method, Oxygen, Physics, Sun, Photosystem, Nature, Oxygen evolution

28

Schizophrenia is a highly heritable disorder. Genetic risk is conferred by a large number of alleles, including common alleles of small effect that might be detected by genome-wide association studies. Here we report a multi-stage schizophrenia genome-wide association study of up to 36,989 cases and 113,075 controls. We identify 128 independent associations spanning 108 conservatively defined loci that meet genome-wide significance, 83 of which have not been previously reported. Associations were enriched among genes expressed in brain, providing biological plausibility for the findings. Many findings have the potential to provide entirely new insights into aetiology, but associations at DRD2 and several genes involved in glutamatergic neurotransmission highlight molecules of known and potential therapeutic relevance to schizophrenia, and are consistent with leading pathophysiological hypotheses. Independent of genes expressed in brain, associations were enriched among genes expressed in tissues that have important roles in immunity, providing support for the speculated link between the immune system and schizophrenia.

Concepts: Immune system, Medicine, Gene, Genetics, Evolution, Organism, Immunity, Genome-wide association study

27

To determine whether time spent outdoors was associated with increased moderate-to-vigorous physical activity (MVPA) and related health benefits in youth.

Concepts: Health economics, Health insurance, Obesity, Exercise

27

Herein we report a rational design strategy for tailoring intermolecular interactions to enhance room-temperature phosphorescence from purely organic materials in amorphous matrices at ambient conditions. The built-in strong halogen and hydrogen bonding between the newly developed phosphor G1 and the poly(vinyl alcohol) (PVA) matrix efficiently suppresses vibrational dissipation and thus enables bright room-temperature phosphorescence (RTP) with quantum yields reaching 24 %. Furthermore, we found that modulation of the strength of halogen and hydrogen bonding in the G1-PVA system by water molecules produced unique reversible phosphorescence-to-fluorescence switching behavior. This unique system can be utilized as a ratiometric water sensor.

Concepts: DNA, Oxygen, Water, Hydrogen, Atom, Carbon, Chemical bonding, Covalent bond

27

The generation of blue-light-emitting pyrotechnic formulations without the use of chlorine-containing compounds is reported. Suitable blue-light emission has been achieved through the generation of molecular emitting copper(I) iodide. The most optimal copper(I) iodide based blue-light-emitting formulation was found to have performances exceeding those of chlorine-containing compositions, and was found to be insensitive to various ignition stimuli.

Concepts: Pharmaceutical formulation, Formulation, Pyrotechnics

27

A method for dating copper/bronze archaeological objects aged in atmospheric environments is proposed based on the specific signals for cuprite and tenorite corrosion products measured through the voltammtry of microparticles method. The tenorite/cuprite ratio increased with the corrosion time and fitted to a potential law that yielded a calibration curve usable for dating purposes.

Concepts: Calibration curve, Cuprite

27

Hip fracture surgery and lower extremity arthroplasty are associated with increased risk of both venous thromboembolism and bleeding. The best pharmacologic strategy for reducing these opposing risks is uncertain.

Concepts: Blood, Bone fracture, Risk, Thrombosis, Hip replacement, Orthopedic surgery, Joint replacement, Uncertainty

26

Since dietary habits have been associated with breast cancer, the tested research hypothesis was the associations between food patterns, as derived through multivariate methods, and breast cancer.

Concepts: Epidemiology, Cancer, Breast cancer, Metastasis, Nutrition, Estrogen, Pleural effusion, Seafood

26

We here highlight recent studies that in vivo demonstrate an involvement of microRNAs in atherosclerotic lesion formation and provide important preclinical evidence of their therapeutic targeting in atherosclerosis, with a particular focus on endothelial cells and macrophages. We also briefly discuss the emerging role of long noncoding RNAs herein.

Concepts: Inflammation, Monocyte, Gene, Atherosclerosis, Macrophage, Blood vessel, Endothelium, Long noncoding RNA