449 research outputs found
Induction skull melt spinning of reactive metal alloys
An apparatus for melting and rapid solidification casting of metal alloys has a crucible for molding a metal charge. The crucible has side walls, a top and a bottom having an orifice therein. Collectively, the side walls, top and bottom define an interior of the crucible. A portion of the dimensions of the side walls of the side walls and bottom is divided by longitudinal slits into at least two segments. A nozzle is disposed partially within the crucible and extends through the orifice. The nozzle has a first end in communication with the interior of tune crucible. A second end of the nozzle has a nozzle orifice therein for defining a stream of molten metal alloy. A cooling mechanism cools the top, side walls and bottom of the crucible. The apparatus has mechanisms for inducing alternating electrical currents within the metal charge and within the nozzle, and for establishing and maintaining pressure within the interior of the crucible. A positioning mechanism positions the crucible and nozzle means relative to a quenching mechanisms that includes a rapidly moving chill substrate. The crucible, nozzle and quenching mechanism are housed within an enclosure that provides there within a controlled atmosphere having positive or negative pressure
Heat treatment of rapidly quenched Fe-6.5 wt % Si ribbon
A rapidly quenched Fe-Si Alloy containing 6 to 7 wt % is heat treated to promote and control an order-disorder reaction, thereby improving its ac core loss and exciting power at induction levels about B=1.2 T. The alloy has a substantially texture, a grain size of about 1 to 2 mm, a R2 domain size of 100 to 850 nm, a DO3 domain size of about 5 to 25 nm, an ac core loss of about 1.2 to 1.6 W/kg and an exciting power of about 15 to 46 VA/kg, the core loss and exciting power being measured at an induction level of B=1.4 T and a frequency of f=60 Hz
Deep brain stimulation can suppress pathological synchronisation in parkinsonian patients
Background Although deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a highly effective therapeutic intervention in severe Parkinson's disease, its mechanism of action remains unclear. One possibility is that DBS suppresses local pathologically synchronised oscillatory activity.Methods To explore this, the authors recorded from DBS electrodes implanted in the STN of 16 patients with Parkinson's disease during simultaneous stimulation (pulse width 60 mu s; frequency 130 Hz) of the same target using a specially designed amplifier. The authors analysed data from 25 sides.Results The authors found that DBS progressively suppressed peaks in local field potential activity at frequencies between 11 and 30 Hz as voltage was increased beyond a stimulation threshold of 1.5 V. Median peak power had fallen to 54% of baseline values by a stimulation intensity of 3.0 V.Conclusion The findings suggest that DBS can suppress pathological 11-30 Hz activity in the vicinity of stimulation in patients with Parkinson's disease. This suppression occurs at stimulation voltages that are clinically effective
Vascular Health in American Football Players: Cardiovascular Risk Increased in Division III Players
Studies report that football players have high blood pressure (BP) and increased cardiovascular risk. There are over 70,000 NCAA football players and 450 Division III schools sponsor football programs, yet limited research exists on vascular health of athletes. This study aimed to compare vascular and cardiovascular health measures between football players and nonathlete controls. Twenty-three athletes and 19 nonathletes participated. Vascular health measures included flow-mediated dilation (FMD) and carotid artery intima-media thickness (IMT). Cardiovascular measures included clinic and 24 hr BP levels, body composition, VO2 max, and fasting glucose/cholesterol levels. Compared to controls, football players had a worse vascular and cardiovascular profile. Football players had thicker carotid artery IMT (0.49 Ā± 0.06 mm versus 0.46 Ā± 0.07 mm) and larger brachial artery diameter during FMD (4.3 Ā± 0.5 mm versus 3.7 Ā± 0.6 mm), but no difference in percent FMD. Systolic BP was significantly higher in football players at all measurements: resting (128.2 Ā± 6.4 mmHg versus 122.4 Ā± 6.8 mmHg), submaximal exercise (150.4 Ā± 18.8 mmHg versus 137.3 Ā± 9.5 mmHg), maximal exercise (211.3 Ā± 25.9 mmHg versus 191.4 Ā± 19.2 mmHg), and 24-hour BP (124.9 Ā± 6.3 mmHg versus 109.8 Ā± 3.7 mmHg). Football players also had higher fasting glucose (91.6 Ā± 6.5 mg/dL versus 86.6 Ā± 5.8 mg/dL), lower HDL (36.5Ā±11.2 mg/dL versus 47.1Ā±14.8 mg/dL), and higher body fat percentage (29.2Ā±7.9% versus 23.2Ā±7.0%). Division III collegiate football players remain an understudied population and may be at increased cardiovascular risk
A Transiting Planet of a Sun-like Star
A planet transits an 11th magnitude, G1V star in the constellation Corona
Borealis. We designate the planet XO-1b, and the star, XO-1, also known as GSC
02041-01657. XO-1 lacks a trigonometric distance; we estimate it to be 200+-20
pc. Of the ten stars currently known to host extrasolar transiting planets, the
star XO-1 is the most similar to the Sun in its physical characteristics: its
radius is 1.0+-0.08 R_Sun, its mass is 1.0+-0.03 M_Sun, V sini < 3 km/s, and
its metallicity [Fe/H] is 0.015+-0.04. The orbital period of the planet XO-1b
is 3.941534+-0.000027 days, one of the longer ones known. The planetary mass is
0.90+-0.07 M_Jupiter, which is marginally larger than that of other transiting
planets with periods between 3 and 4 days. Both the planetary radius and the
inclination are functions of the spectroscopically determined stellar radius.
If the stellar radius is 1.0+-0.08 R_Sun, then the planetary radius is
1.30+-0.11 R_Jupiter and the inclination of the orbit is 87.7+-1.2 degrees. We
have demonstrated a productive international collaboration between professional
and amateur astronomers that was important to distinguishing this planet from
many other similar candidates.Comment: 31 pages, 9 figures, accepted for part 1 of Ap
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The chaperone protein HSP47: a platelet collagen binding protein that contributes to thrombosis and haemostasis
Objective: Heat shock protein 47 (HSP47) is an intracellular chaperone protein that is vital for collagen biosynthesis in collagen secreting cells. This protein has also been shown to be present on the surface of platelets. Given the importance of collagen and its interactions with platelets in triggering haemostasis and thrombosis, in this study we sought to characterise the role of HSP47 on these cells.
Approach and Results: The deletion of HSP47 in mouse platelets or its inhibition in human platelets reduced their function in response to collagen and the GPVI agonist (CRP-XL), but responses to thrombin were unaltered. In the absence of functional HSP47, the interaction of collagen with platelets was reduced, and this was associated with reduced GPVI-collagen binding, signalling and platelet activation. Thrombus formation on collagen, under arterial flow conditions was also decreased following the inhibition or deletion of HSP47, in the presence or absence of the eptifibatide, consistent with a role for HSP47 in enhancing platelet adhesion to collagen. Platelet adhesion under flow to von Willebrand Factor was unaltered following HSP47 inhibition. Laser-induced thrombosis in cremaster muscle arterioles was reduced and bleeding time was prolonged in HSP47 deficient mice or following inhibition of HSP47.
Conclusions: Our study demonstrates the presence of HSP47 on the platelet surface where it interacts with collagen, stabilises platelet adhesion and increases collagen mediated signalling and therefore thrombus formation and haemostasis
Three Stages of Lysozyme Thermal Stabilization by High and Medium Charge Density Anions
Addition of high and medium charge density anions (phosphate, sulfate, and chloride) to lysozyme in pure water demonstrates three stages for stabilization of the protein structure. The first two stages have a minor impact on lysozyme stability and are probably associated with direct interaction of the ions with charged and partial charges on the proteinās surface. There is a clear transition between the second and third stages; in the case of sodium chloride, disodium sulfate and disodium hydrogen phosphate this is at 550, 210, and 120 mM, respectively. Stabilization of lysozyme can be explained by the free energy required to hydrate the protein as it unfolds. At low ion concentrations, the proteinās hydration layer is at equilibrium with the bulk water. After the transition, bulk water is depleted and the protein is competing for water with the ions. With competition for water between the protein and the ions at higher salt concentrations, the free energy required to hydrate the interior of the protein rises and it is this that stabilizes the protein structure
Leading Disability Research and Workforce Development: A Western Sydney Collaboration
In this White Paper we draw attention to the potential of excellence in research and workforce development as a means, in part, to foster greater inclusion and participation for people with disability. We present a critique of the current limitations in research and workforce development and highlight the urgency to address such shortcomings to realise inclusion within our communities. We demonstrate that Western Sydney University is well positioned as a leading institution to address many of these concerns. This White paper showcases the innovative work of our team, and calls for seven key actions, to advance inclusion and participation for people and communities in Greater Western Sydney, Australia, and beyond
Autonomous sound recording outperforms human observation for sampling birds: a systematic map and user guide
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