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Laboratory experiments in microcosms monitoring the hydrocarbon composition of degraded oils are used with carbon isotopic compositions of gas and oil samples taken at wellheads and a Rayleigh isotope fractionation box model to elucidate the mechanisms of hydrocarbon degradation in reservoirs. The data imply a common methanogenic biodegradation mechanism in subsurface degraded oil reservoirs resulting in consistent patterns of hydrocarbon alteration.
Aberration-corrected scanning transmission electron microscopy, coupled with simple imaging simulation, is used to determine with atomic resolution the size, three-dimensional shape, orientation and atomic arrangement of size-selected gold nanoclusters that are preformed in the gas phase and soft-landed on an amorphous carbon substrate.
A receptor for the Drosophila melanogaster sex peptide (SP), the primary trigger of post-mating responses, is identified. Females lacking the sex peptide receptor (either entirely or only in the nervous system) fail to respond to SP and continue to show virgin behaviours, even after mating.
The protein component of the major urinary protein complex is identified as a potential pheromone ligand mediating male–male aggression via the accessory olfactory pathway.
One of two papers that demonstrate that a single quantum dot placed within an optical cavity can directly block incoming photons when it is strongly coupled to the cavity's optical field. InAs quantum dots placed respectively inside photonic crystal vacancies and inside GaAs microdisks, observe strong coupling directly in the optical transmission signal.
If a stable layer of dense melt formed at the base of the mantle early in Earth's history, it would have undergone slow fractional crystallization and could provide an unsampled geochemical reservoir hosting a variety of incompatible geochemical species (most notably the missing budget of heat producing elements).
One of two papers that demonstrate that a single quantum dot placed within an optical cavity can directly block incoming photons when it is strongly coupled to the cavity's optical field. InAs quantum dots placed respectively inside photonic crystal vacancies and inside GaAs microdisks, observe strong coupling directly in the optical transmission signal.
Evidence for 'supersolidity' has been found in 4He from torsional oscillator measurements that suggest some of the solid decouples at low temperatures. Other signatures of superflow have not been seen, but there may be clues in the solid's mechanical behaviour. This study finds large increases in the shear modulus of solid 4He at low temperatures that appear closely related to the decoupling seen in the torsional oscillator experiments.
The result of U–Pb dating of minerals in a lunar meteorite, Kalahari 009 is reported. Analyses of five grains associated with basaltic clasts give an age of 4.35 ± 0.15 billion years. These are thought to represent the crystallization ages of parental basalt magma, making Kalahari 009 one of the oldest known mare basalt. This suggests that mare basalt volcanism on the Moon started as early as 4.35 billion years ago.
Cryo-electron tomography of vitreous section from human skin is used to investigate the architecture of cadherin molecules in desmosomes under near native conditions. Three-dimensional reconstructions and fitting of existing X-ray crystallography data reveal a regular array of molecules in desmosomes, that is consistent with data derived previously using different methods.
Tumours promote Bv8 expression in myeloid cells in the bone marrow. Bv8 acts on endothelial cells to directly promote tumour angiogenesis as well as to promote the recruitment of CD11b+Gr1+ myeloid cells from the bone to tumours.
A model study of the coupled evolution of the carbon cycle and the climate system during the Neoproterozoic is presented. This finds that more oxygen is taken up by a cooling ocean, which converts organic into inorganic carbon more efficiently, creating a negative feedback loop that stabilises low carbon dioxide levels and prevents total glaciation.
Tachycardia can be prevented by engrafting embryonic cardiomyocytes into mice. A protein resident at 'gap junctions', connexin 43, is also identified as being important for this protection. Expression of this protein in skeletal myoblasts achieves similar levels of protection. These results suggest a new approach to cell-based therapy for cardiac dysfunction.
A combination of novel surface chemistry and fluorescence microscopy allows visualization of dynamic microtubules and plus-end tracking proteins in real time. Three microtubule binding proteins from fission yeast in the in vitro reconstitution system are used, and the results presented yield new insights into the mechanism of plus-end binding proteins in microtubule dynamics.
Bacterial cultures experiencing changes in environmental conditions accumulate mutator strains, presumably to enhance their capability for adaptive evolution. The presence of bacterial viruses is demonstrated to have a similar effect, as during co-evolution of Pseudomonas fluorescens and its lytic DNA phage, bacterial mutation rates significantly increase, resulting in a higher probability of phage extinction.
Observations of Venus' ionosphere reveal strong, circularly-polarized, electromagnetic waves with frequencies near 100 Hz. The waves appear as bursts of radiation lasting 0.25 to 0.5 s and have the expected properties of whistler-mode signals generated by lightning discharges in Venus' clouds.
