6,910 research outputs found

    A gas-liquid solid phase peptide and protein sequenator

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    A new miniaturized protein and peptide sequenator has been constructed which uses gas phase reagents at the coupling and cleavage steps of the Edman degradation. The sample is embedded in a matrix of Polybrene dried onto a porous glass fiber disc located in a small cartridge-style reaction cell. The protein or peptide, though not covalently attached to the support, is essentially immobile throughout the degradative cycle, since only relatively apolar, liquid phase solvents pass through the cell. This instrument can give useful sequence data on as little as 5 pmol or protein, can perform extended sequence runs (greater than 30 residues) on subnanomole quantities of proteins purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and can sequence hydrophobic peptides to completion. The sequenator is characterized by a high repetitive yield during the degradation, low reagent consumption, low maintenance requirements, and a degradative cycle time of only 50 min using a complete double cleavage program

    Riemann solvers and undercompressive shocks of convex FPU chains

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    We consider FPU-type atomic chains with general convex potentials. The naive continuum limit in the hyperbolic space-time scaling is the p-system of mass and momentum conservation. We systematically compare Riemann solutions to the p-system with numerical solutions to discrete Riemann problems in FPU chains, and argue that the latter can be described by modified p-system Riemann solvers. We allow the flux to have a turning point, and observe a third type of elementary wave (conservative shocks) in the atomistic simulations. These waves are heteroclinic travelling waves and correspond to non-classical, undercompressive shocks of the p-system. We analyse such shocks for fluxes with one or more turning points. Depending on the convexity properties of the flux we propose FPU-Riemann solvers. Our numerical simulations confirm that Lax-shocks are replaced by so called dispersive shocks. For convex-concave flux we provide numerical evidence that convex FPU chains follow the p-system in generating conservative shocks that are supersonic. For concave-convex flux, however, the conservative shocks of the p-system are subsonic and do not appear in FPU-Riemann solutions

    M/L, H-alpha Rotation Curves, and HI Measurements for 329 Nearby Cluster and Field Spirals: II. Evidence for Galaxy Infall

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    We have conducted a study of optical and HI properties of spiral galaxies (size, luminosity, H-alpha flux distribution, circular velocity, HI gas mass) to explore the role of gas stripping as a driver of morphological evolution in clusters. We find a strong correlation between the spiral and S0 fractions within clusters, and the spiral fraction scales tightly with cluster X-ray gas luminosity. We explore young star formation and identify spirals that are (1) asymmetric, with truncated H-alpha emission and HI gas reservoirs on the leading edge of the disk, on a first pass through the dense intracluster medium in the cores of rich clusters; (2) strongly HI deficient and stripped, with star formation confined to the inner 5 kpc/h and 3 disk scale lengths; (3) reddened, extremely HI deficient and quenched, where star formation has been halted across the entire disk. We propose that these spirals are in successive stages of morphological transformation, between infalling field spirals and cluster S0s, and that the process which acts to remove the HI gas reservoir suppresses new star formation on a similarly fast timescale. These data suggest that gas stripping plays a significant role in morphological transformation and rapid truncation of star formation across the disk.Comment: 24 pages, 12 figures; accepted for publication in AJ; higher-resolution figures available at http://astronomy.nmsu.edu/nicol

    Healthy lifestyle interventions in general practice: Part16: Lifestyle and fibromyalgia

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    Fibromyalgia is a chronic disorder, characterised by chronic widespread musculoskeletal pain, and the presence of multiple tender points as well as a host of associated symptomatology. Optimal management of patients with fibromyalgia requires a multidisciplinary approach, with a combination of pharmacological and non-pharmacological interventions that are tailored to the patient's pain, dysfunction and associated features, including depression, sleep disorder and fatigue. Non-pharmacological lifestyle-based interventions to treat this disorder include exercise therapy, dietary modification, and psychosocial interventions. This review outlines these three forms of lifestyle intervention in patients with fibromyalgia

    Healthy lifestyle interventions in general practice Part 4: Lifestyle and diabetes mellitus

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    Diabetes mellitus, in particular Type 2 diabetes, can be classified as a chronic disease of lifestyle. A lifestyle intervention programme is therefore an essential component of the primary and secondary prevention (management) of diabetes mellitus. The main indication for referral to a lifestyle intervention programme is any patient with either pre-diabetes or established diabetes mellitus. Following a comprehensive initial assessment, patients are recommended to attend either a group-based programme (medically supervised or medically directed, depending on the severity of the disease and the presence of any co-morbidities) or a home-based intervention programme. The main elements of the intervention programme are nutritional intervention, exercise training (minimum of 150 minutes at moderate intensity per week), psychosocial support and education. Regular monitoring should be conducted during training sessions, and a follow-up assessment is indicated after 2–3 months to assess progress and to re-set goals. Longer-term (5–6 months) intervention programmes are associated with better long-term outcomes

    A 180 Kpc Tidal Tail in the Luminous Infrared Merger Arp 299

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    We present VLA HI observations and UH88 deep optical B- and R-band observations of the IR luminous merger Arp 299 (= NGC 3690 + IC 694). These data reveal a gas-rich, optically faint tidal tail with a length of over 180 kpc. The size of this tidal feature necessitates an old interaction age for the merger (~750 Myr since first periapse), which is currently experiencing a very young star burst (~20 Myr). The observations reveal a most remarkable structure within the tidal tail: it appears to be composed of two parallel filaments separated by ~20 kpc. One of the filaments is gas rich with little if any starlight, while the other is gas poor. We believe that this bifurcation results from a warped disk in one of the progenitors. The quantities and kinematics of the tidal HI suggest that Arp 299 results from the collision of a retrograde Sab-Sb galaxy (IC 694) and a prograde Sbc-Sc galaxy (NGC 3690) that occurred 750 Myr ago and which will merge into a single object in ~60 Myr. We suggest that the present IR luminous phase in this system is due in part to the retrograde spin of IC 694. Finally, we discuss the apparent lack of tidal dwarf galaxies within the tail.Comment: LaTex, 14 pages, 11 figures, 4 tables, uses emulateapj.sty. Accepted to AJ for July 1999. For version with full-resolution images see http://www.cv.nrao.edu/~jhibbard/a299/HIpaper/a299HI.htm

    Healthy lifestyle interventions in general practice. Part 2: Lifestyle and cardiovascular disease

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    This article forms the second part of the series on the role of lifestyle modification in general practice with specific reference to chronic cardiovascular disease. Whilst the major risk factors which constitute an unhealthy lifestyle were discussed in part 1 of this series, the focus of part 2 will give specific practical guidelines which the general practitioner may incorporate into their practice when counselling patients with chronic cardiovascular disease
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