11,306 research outputs found
In vivo imaging of pyrrole-imidazole polyamides with positron emission tomography
The biodistribution profiles in mice of two pyrrole-imidazole polyamides were determined by PET. Pyrrole-imidazole polyamides are a class of small molecules that can be programmed to bind a broad repertoire of DNA sequences, disrupt transcription factor-DNA interfaces, and modulate gene expression pathways in cell culture experiments. The 18F-radiolabeled polyamides were prepared by oxime ligation between 4-[18F]-fluorobenzaldehyde and a hydroxylamine moiety at the polyamide C terminus. Small animal PET imaging of radiolabeled polyamides administered to mice revealed distinct differences in the biodistribution of a 5-ring β-linked polyamide versus an 8-ring hairpin, which exhibited better overall bioavailability. In vivo imaging of pyrrole-imidazole polyamides by PET is a minimum first step toward the translation of polyamide-based gene regulation from cell culture to small animal studies
Encore for the enclave: the changing nature of the industry enclave with illustrations from the mining industry in Chile
Conceptual innovation with respect to the enclave concept has been virtually absent compared with that on industry agglomerations. This is despite the fact that some varieties of agglomeration distinguished in the literature appear to come close to what previously were regarded as industrial enclaves and despite frequent allusions to the enclave nature of economic spaces produced by contemporary processes of globalization. Bringing the literature on agglomeration and enclaves into dialogue, we revisit the concept of the enclave - a concept that has been largely neglected since it enjoyed a popularity in connection with the study of particular (notably extractive) industries and particular (notably dependencia) theories of national economic development during the 1960s and 1970s. Much has changed since this time which suggests that the concept of the enclave ought to be ripe for re-evaluation. In this paper we take an initial step in this direction identifying analytical dimensions to the enclave and illustrating different manifestations of enclaves in the mining industry, drawing on the case of Chile. We conclude by advocating the renewed study of industry enclaves within contemporary economic geographical analysis
Tunable Transient Decay Times in Nonlinear Systems: Application to Magnetic Precession
The dynamical motion of the magnetization plays a key role in the properties
of magnetic materials. If the magnetization is initially away from the
equilibrium direction in a magnetic nanoparticle, it will precess at a natural
frequency and, with some damping present, will decay to the equilibrium
position in a short lifetime. Here we investigate a simple but important
situation where a magnetic nanoparticle is driven non-resonantly by an
oscillating magnetic field, not at the natural frequency. We find a surprising
result that the lifetime of the transient motion is strongly tunable, by
factors of over 10,000, by varying the amplitude of the driving field.Comment: EPL Preprin
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Mispositioned Neurokinin-1 Receptor-Expressing Neurons Underlie Heat Hyperalgesia in Disabled-1 Mutant Mice.
Reelin (Reln) and Disabled-1 (Dab1) participate in the Reln-signaling pathway and when either is deleted, mutant mice have the same spinally mediated behavioral abnormalities, increased sensitivity to noxious heat and a profound loss in mechanical sensitivity. Both Reln and Dab1 are highly expressed in dorsal horn areas that receive and convey nociceptive information, Laminae I-II, lateral Lamina V, and the lateral spinal nucleus (LSN). Lamina I contains both projection neurons and interneurons that express Neurokinin-1 receptors (NK1Rs) and they transmit information about noxious heat both within the dorsal horn and to the brain. Here, we ask whether the increased heat nociception in Reln and dab1 mutants is due to incorrectly positioned dorsal horn neurons that express NK1Rs. We found more NK1R-expressing neurons in Reln-/- and dab1-/- Laminae I-II than in their respective wild-type mice, and some NK1R neurons co-expressed Dab1 and the transcription factor Lmx1b, confirming their excitatory phenotype. Importantly, heat stimulation in dab1-/- mice induced Fos in incorrectly positioned NK1R neurons in Laminae I-II. Next, we asked whether these ectopically placed and noxious-heat responsive NK1R neurons participated in pain behavior. Ablation of the superficial NK1Rs with an intrathecal injection of a substance P analog conjugated to the toxin saporin (SSP-SAP) eliminated the thermal hypersensitivity of dab1-/- mice, without altering their mechanical insensitivity. These results suggest that ectopically positioned NK1R-expressing neurons underlie the heat hyperalgesia of Reelin-signaling pathway mutants, but do not contribute to their profound mechanical insensitivity
Response and Recovery of the Comanche Carbonate Platform Surrounding Multiple Cretaceous Oceanic Anoxic Events, Northern Gulf of Mexico
The ubiquity of carbonate platforms throughout the Cretaceous Period is recognized as a product of high eustatic sea-level and a distinct climatic optimum induced by rapid sea-floor spreading and elevated levels of atmospheric carbon-dioxide. Notably, a series of global oceanic anoxic events (OAEs) punctuate this time-interval and mark periods of significantly reduced free oxygen in the world's oceans. The best records of these events are often from one-dimensional shelf or basin sections where only abrupt shifts between oxygenated carbonates and anoxic shales are recorded. The Comanche Platform of central Texas provides a unique opportunity to study these events within a well-constrained stratigraphic framework in which their up-dip and down-dip sedimentologic effects can be observed and the recovery of the platform to equilibrium states can be timed and understood. Stable isotope data from whole cores in middle Hauterivian through lower Campanian mixed carbonate-siliciclastic strata are used to construct a 52-myr carbon isotope reference profile for the northern Gulf of Mexico. Correlation of this composite curve to numerous global reference profiles permits identification of several anoxic events and allows their impact on platform architecture and fades distribution to be documented. Oceanic anoxic events la, 1b, 1d, and 2 occurred immediately before, after, or during shale deposition in the Pine Island Member, Bexar Member, Del Rio Formation, and Eagle Ford Group, respectively. Oceanic anoxic event 3 corresponds to deposition of the Austin Chalk Group. Platform drowning on three occasions more closely coincided with globally recognized anoxic sub-events such as the Fallot, Albian-Cenomanian, and Mid-Cenomanian events. This illustrates that the specific anoxic event most affecting a given carbonate platform varied globally as a function of regional oceanographic circumstances. Using chemo- and sequence-stratigraphic observations, a four-stage model is proposed to describe the changing fades patterns, fauna, sedimentation accumulation rates, platform architectures, and relative sea-level trends of transgressive-regressive composite sequences that developed in response to global carbon-cycle perturbations. The four phases of platform evolution include the equilibrium, crisis, anoxic, and recovery stages. The equilibrium stage is characterized by progradational shelf geometries and coralrudist phototrophic faunal assemblages. Similar phototrophic fauna typify the crisis stage; however, incipient biocalcification crises of this phase led to retrogradational shelf morphologies, transgressive facies patterns, and increased clay mineral proportions. Anoxic stages of the Comanche Platform were coincident with back-ground deposition of organic-rich shale on drowned shelves and heterotrophic fauna dominated by oysters or coccolithophorids. Eustatic peaks of this stage were of moderate amplitude (similar to 30 m), yet relative sea-level rises were greatly enhanced by reduced sedimentation rates. In the recovery stage, heterotrophic carbonate factories re-established at the shoreline as progradational ramp systems and sediment accumulation rates slowly increased as dysoxia diminished. Full recovery to equilibrium conditions may or may not have followed. Geochemical and stratigraphic trends present in the four stages are consistent with increased volcanism along mid-ocean ridges and in large-igneous provinces as primary drivers of Cretaceous OAEs and the resulting transgressive-regressive composite sequences. (C) 2014 Elsevier Ltd. All rights reserved.BHP-BillitonReservoir Characterization Research Laboratory, the Bureau of Economic GeologyJackson School of Geosciences at the University of Texas at AustinBureau of Economic Geolog
Spring joint with overstrain sensor
A flexible joint may include a conductive compression spring and a pair of non-conductive spring cages disposed at opposite ends of the compression spring to support the compression spring. A conductive member disposed inside the compression spring may extend between the pair of spring cages. One end of the conductive member may be fixed for movement with one of the spring cages and another end of the conductive member may be fixed for movement with the other of the spring cages
A Sensitive Faraday Rotation Setup Using Triple Modulation
The utilization of polarized targets in scattering experiments has become a
common practice in many major accelerator laboratories. Noble gases are
especially suitable for such applications, since they can be easily
hyper-polarized using spin exchange or metastable pumping techniques. Polarized
helium-3 is a very popular target because it often serves as an effective
polarized neutron due to its simple nuclear structure. A favorite cell material
to generate and store polarized helium-3 is GE-180, a relatively dense
aluminosilicate glass. In this paper, we present a Faraday rotation method,
using a new triple modulation technique, where the measurement of the Verdet
constants of SF57 flint glass, pyrex glass, and air were tested. The
sensitivity obtained shows that this technique may be implemented in future
cell wall characterization and thickness measurements. We also discuss the
first ever extraction of the Verdet constant of GE-180 glass for four
wavelength values of 632 nm, 773 nm, 1500 nm, and 1547 nm, whereupon the
expected 1/{\lambda}^{2} dependence was observed.Comment: 4 pages, 2 figures Updated version for RSI submissio
Societal psychology in Norway
This special issue is comprised of a diverse collection of theoretical and empirical papers from Norway. The choice of societal psychology as a means of organizing these contributions will be discussed in this introduction. Although the term is infrequently used internationally, it has been adopted as the closest translation for the Norwegian disciplinary boundary samfunnspsykologi, which has structured each main contributor’s experience of psychology as graduate or post-‐graduate researchers. I also hope to illustrate that Himmelweit’s (1990) original conceptualization of societal psychology is also appropriate to unify these articles due to its openness toward multiple theoretical and methodological perspectives
Laser gas-discharge absorption measurements of the ratio of two transition rates in argon
The ratio of two line strengths at 922.7 nm and 978.7 nm of argon is measured
in an argon pulsed discharge with the use of a single-mode Ti:Sapphire laser.
The result 3.29(0.13) is in agreement with our theoretical prediction 3.23 and
with a less accurate ratio 2.89(0.43) from the NIST database.Comment: 5 pages, 2 figures, 1 tabl
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