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

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

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

Economic Foundations of Cost Effective Analysis

In order to address several controversies in the application of cost-effectiveness analysis, we investigate the principles underlying the technique and discuss the implications for the evaluation of medical interventions. Using a standard von Neumann-Morgenstern utility framework, we show how a cost-effectiveness criterion can be derived to guide resource allocation decisions. We investigate its relation to age, gender, income level, and risk aversion. Cost-effectiveness analysis can be a useful and powerful tool for resource allocation decisions, but in the presence of heterogeneous preferences and personal characteristics, a cost-effectiveness criterion that is applied at the population level is unlikely to yield pareto-optimal resource allocations.

A Note on The Structure of Morphactin-Induced Wood in Two Coniferous Species

Anatomical features of vertically growing apical shoots of Pinus sylvestris L. and Picea excelsa Link, trees treated with 0.3% morphactin IT 3456 in lanolin paste were analyzed with light and scanning electron microscopes. These studies indicated that the wood formed above and at the area of treatment was morphologically similar to compression wood. Reasons for production of compression wood after treatment with morphactin in vertically growing shoots are discussed

Afadin orients cell division to position the tubule lumen in developing renal tubules

In many types of tubules, continuity of the lumen is paramount to tubular function, yet how tubules generate lumen continuity in vivo is not known. We recently found the F-actin binding protein Afadin is required for lumen continuity in developing renal tubules, though its mechanism of action remains unknown. Here we demonstrate Afadin is required for lumen continuity by orienting the mitotic spindle during cell division. Using an in vitro 3D cyst model, we find Afadin localizes to the cell cortex adjacent to the spindle poles and orients the mitotic spindle. In tubules, cell division may be oriented relative to two axes, longitudinal and apical-basal. Unexpectedly, in vivo examination of early stage developing nephron tubules reveals cell division is not oriented in the longitudinal (or planar polarized) axis. However, cell division is oriented perpendicular to the apical-basal axis. Absence of Afadin in vivo leads to misorientation of apical-basal cell division in nephron tubules. Together these results support a model whereby Afadin determines lumen placement by directing apical-basal spindle orientation, which generates a continuous lumen and normal tubule morphogenesis

A qualitative study exploring the experience of viewing three‐dimensional medical images during an orthopaedic outpatient consultation from the perspective of patients, health care professionals, and lay representatives

Rationale, aims and objectives Three‐dimensional (3D) medical images are shown to patients during clinical consultations about certain health conditions. However, little is known about patients' experience of viewing them. The aim of this qualitative study was to explore the impact of sharing 3D medical images with patients during a clinical consultation about hip surgery, from the perspective of patients, health care professionals, and lay representatives. Method Interviews were conducted with 14 patients who were shown their own 3D medical images during their clinical consultation and four health care professionals conducting consultations within one orthopaedic outpatient clinic. In addition to interviews, 31 lay representatives participated in six focus groups. The focus groups aimed to gain a broader understanding of the advantages and concerns of showing patients their medical images and to compare 3D and two‐dimensional (2D) medical images. Interviews and focus groups were audio‐recorded, transcribed verbatim, and analysed using thematic analysis. Results Three themes were developed from the data: (a) the truthful image, (b) the empowering image, and (c) the unhelpful image. Focus group participants' preference for 3D or 2D images varied between conditions and groups, suggesting that the experience of viewing images may differ between individuals and conditions. Conclusions When shown to patients during an orthopaedic clinical consultation, 3D medical images may be an empowering resource. However, in this study, patients and focus group participants perceived medical images as factual and believed they could provide evidence of a diagnoses. This perception could result in overreliance in imaging tests or disregard for other forms of information

Algebraic lattice constellations: bounds on performance

In this work, we give a bound on performance of any full-diversity lattice constellation constructed from algebraic number fields. We show that most of the already available constructions are almost optimal in the sense that any further improvement of the minimum product distance would lead to a negligible coding gain. Furthermore, we discuss constructions, minimum product distance, and bounds for full-diversity complex rotated Z[i]/sup n/-lattices for any dimension n, which avoid the need of component interleaving

Constitutive soluble methane monooxygenase mutants of methanotrophic bacteria such as Methylosinus trichosporium A.T.C.C. 55314

Selection of mutant methanotrophic bacteria capable of efficiently degrading halogenated hydrocarbons typically found in numerous wastewater sources is described. The mutants are distinguishable from parental strains in having a unique resistance to the presence of copper while exhibiting unusually high degradation rates toward trichlorethylene. Methylosinus trichosporium A.T.C.C. 55314 strains are particularly good sources of the described mutants which may be obtained using a new method of selection and screening. The disclosed microorganisms may be immobilized on various matrices and are particularly adaptable for use in bioreactors. Further, the methanotrophic bacteria have antibiotic resistance to streptomycin or rifampicin B.Board of Regents, University of Texas Syste