Jay Keasling, Berkeley Lab ALD for Biosciences and CEO of the Joint BioEnergy Institute, appears in a video on biotechnology at the Smithsonian's National Museum of American History. The video is part of en exhibit titled "Science in American Life," which examines the relationship between science, technology, progress and culture through artifacts, historical photographs and multimedia technology.
The current status of the problem of small cracks in fatigue is presented. Several classes of small cracks are distinguished, and their individual characteristics described. Specifically, for cracks small compared with microstructural size scales, for cracks small compared with the extent of local plasticity or for cracks which are either chemically or physically small (e.g. about 1 mm or less), comments are made on the origins of differences in behavior between large and small cracks, on the question of the “driving force” for small crack advance and on the possible existence of intrinsic thresholds for crack growth. Finally, some thoughts are offered on the use of smallcrack methodology in life prediction analyses and in alloy design.
A new method is given, which converts a chaotic motion in Chua's circuit to a periodic motion. A tunnel mechanism is used to perform this conversion.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Vascular smooth muscle cell (VSMC) and leukocyte proliferation are central features of atherosclerosis. Using 2 H 2 O to label the deoxyribose moiety of newly synthesized DNA in VSMC and atheroma cells from mouse aorta, we developed a method to measure DNA replication and, hence, cell division. Cell turnover/proliferation in aortae from normal and apolipoprotein E (ApoE)-knockout ( ApoE −/− ) mice was measured. Mice were injected with 2 H 2 O to achieve 2% body water enrichments and then maintained on 4% 2 H 2 O in drinking water for weeks to months. DNA from the intimal-medial layer of the aorta was extracted and hydrolyzed to deoxyribonucleosides. Purified deoxyadenosine was derivatized to pentane tetraacetate for analysis of 2 H enrichment by gas chromatography-mass spectrometry. VSMC proliferation was measurable but slow in adult mice (0.12 ± 0.08%/day) and higher in young mice (0.25 ± 0.08%/day). VSMC delabeling revealed that 2 H died away slowly in VSMC DNA, confirming the low turnover rate. Atheroma cell proliferation was elevated in ApoE −/− mice fed low- or high-fat diets for 15 wk, concurrent with histological appearance of atherosclerosis. Validation of the method for VSMC was confirmed by comparison of in vitro rat VSMC proliferation rates using 2 H 2 O with cell counts and bromodeoxyuridine proliferative index. In summary, proliferation of VSMC and atheroma cells can be quantified reliably and sensitively without radioactivity and may be an informative biomarker in vascular hyperplastic diseases, including atherosclerosis.
Crystallographically oriented and highly elongate magnetite inclusions in clinopyroxene are the dominant source of highly stable remanent magnetization in gabbros of the Early Cretaceous Messum Complex, Namibia. Rock magnetic properties determined for individual pyroxene crystals indicate a high proportion of single‐domain magnetite, consistent with the observed sizes and shape anisotropy of the magnetite inclusions. As in previous studies of similar inclusions, these are inferred to have formed by exsolution. Two arrays of inclusions are regularly present in the Messum clinopyroxenes, inclined at about 74°, consistent with formation at about 800°C deduced from optimization of phase boundary orientations. Virtual geomagnetic poles from these rocks are consistent with reference data, confirming that the magnetization is of thermoremanent origin. Bipolar magnetizations are recorded at one site as well in individual clinopyroxene crystals, suggesting that remanence acquisition upon initial cooling of the gabbro spanned a geomagnetic polarity reversal.
Described herein are metallic excavated nanoframes and methods for producing metallic excavated nanoframes. A method may include providing a solution including a plurality of excavated nanoparticles dispersed in a solvent, and exposing the solution to chemical corrosion to convert the plurality of excavated nanoparticles into a plurality of excavated nanoframes.
Nature abounds with complex patterns and structures emerging from homogenous media operating far from thermodynamic equilibrium. Such phenomena, which are widely observed in both inanimate (non-biological) and biological media, can be modeled and studied via the CNN (Cellular Neural/Nonlinear Network) paradigm in an in-depth and unified way. Whether a homogeneous medium is capable of exhibiting complexity depends on whether the CNN cells, or its couplings, is locally active in a precise mathematical sense. This local activity principle is of universal generality and is responsible for all symmetry breaking phenomena observed in a great variety of non-equilibrium media ranging from the emergence of negative differential conductance in bulk semiconductor materials (e.g., Gallium Arsenide in Gunn Diodes) to the emergence of artificial life itself. The main result of this paper consists of a set of explicit analytical conditions for calculating the parameter ranges necessary for the emergence of a non-homogeneous static or dynamic pattern in a homogeneous medium operating under an influx of energy and/or matter. The resulting "complexity related" inequalities are applicable to all media, continuous or discrete, which have been mapped into a CNN paradigm.
