2,672 research outputs found
Marker of Bone Resorption in Acute Response to Exogenous or Endogenous Parathyroid Hormone
Parathyroid hormone (PTH) changes morphology of osteoclasts within minutes after its systemic administration. The aim of our study was to test in healthy men whether both exogenous and endogenous PTH could change acutely (minutes to hours) the serum cross-linked C-telopeptide of type I collagen (beta CTX), which is released during osteoclastic resorption of bone. Twelve healthy men (age range 24–34 yr) were each studied during 180 min on a control period, after a single subcutaneous injection of teriparatide, and after 30 min EDTA infusion to stimulate endogenous PTH secretion. The tests were started after overnight fast, 3 h after a standard calcium load. The EDTA infusion induced a significant decrease in serum ionized calcium (by 8.5% at 33 min) and a significant increase in plasma PTH (by 305% at 33 min). Both the EDTA and teriparatide resulted in a significant increase in beta CTX (p < 0.001) with maximum increases of 64% and 80%, respectively. A mild, but significant decrease in beta CTX was observed during the control test period. In conclusion, single-dose teriparatide injection as well as a stimulation of endogenous PTH in healthy men results in an acute increase of the bone resorption marker
Effect of human auditory efferent feedback on cochlear gain and compression
The manunalian auditory system includes a brainstem-mediated efferent pathway from the superior olivary complex by way of the medial olivocochlear system, which reduces the cochlear response to sound (Warr and Guinan, 1979; Liberman et al., 1996). The human medial olivocochlear response has an onset delay of between 25 and 40 ms and rise and decay constants in the region of 280 and 160 ms, respectively (Backus and Guinan, 2006). Physiological studies with nonhuman mammals indicate that onset and decay characteristics of efferent activation are dependent on the temporal and level characteristics of the auditory stimulus (Bacon and Smith, 1991; Guinan and Stankovic, 1996). This study uses a novel psychoacoustical masking technique using a precursor sound to obtain a measure of the efferent effect in humans. This technique avoids confounds currently associated with other psychoacoustical measures. Both temporal and level dependency of the efferent effect was measured, providing a comprehensive measure of the effect of human auditory efferents on cochlear gain and compression. Results indicate that a precursor (>20 dB SPL) induced efferent activation, resulting in a decrease in both maximum gain and maximum compression, with linearization of the compressive function for input sound levels between 50 and 70 dB SPL. Estimated gain decreased as precursor level increased, and increased as the silent interval between the precursor and combined masker-signal stimulus increased, consistent with a decay of the efferent effect Human auditory efferent activation linearizes the cochlear response for mid-level sounds while reducing maximum gain
Creep and fracture behavior of peak-aged Mg-11Y-5Gd-2Zn-0.5Zr (wt pct)
The tensile-creep and creep-fracture behavior of peak-aged Mg-11Y-5Gd-2Zn-0.5Zr (wt pct) (WGZ1152) was investigated at temperatures between 523 K (250 °C) to 598 K (325 °C) (0.58 to 0.66 T m) and stresses between 30 MPa to 140 MPa. The minimum creep rate of the alloy was almost two orders of magnitude lower than that for WE54-T6 and was similar to that for HZ32-T5. The creep behavior exhibited an extended tertiary creep stage, which was believed to be associated with precipitate coarsening. The creep stress exponent value was 4.5, suggesting that dislocation creep was the rate-controlling mechanism during secondary creep. At T = 573 K (300 °C), basal slip was the dominant deformation mode. The activation energy for creep (Q avg = 221 ± 20 kJ/mol) was higher than that for self-diffusion in magnesium and was believed to be associated with the presence of second-phase particles as well as the activation of nonbasal slip and cross slip. This finding was consistent with the slip-trace analysis and surface deformation observations, which revealed that the nonbasal slip was active. The minimum creep rate and time-to-fracture followed the original and modified Monkman-Grant relationships. The microcracks and cavities nucleated preferentially at grain boundaries and at the interface between the matrix phase and the second phase. In-situ creep experiments highlighted the intergranular cracking evolution
Enabling onshore CO2 storage in Europe: fostering international cooperation around pilot and test sites
To meet the ambitious EC target of an 80% reduction in greenhouse gas emissions by 2050, CO2 Capture and Storage (CCS) needs to move rapidly towards full scale implementation with geological storage solutions both on and offshore. Onshore storage offers increased flexibility and reduced infrastructure and monitoring costs. Enabling onshore storage will support management of decarbonisation strategies at territory level while enhancing security of energy supply and local economic activities, and securing jobs across Europe. However, successful onshore storage also requires overcoming some unique technical and societal challenges. ENOS will provide crucial advances to help foster onshore CO2 storage across Europe through:
1. Developing, testing and demonstrating in the field, under "real-life conditions", key technologies specifically adapted to onshore storage.
2. Contributing to the creation of a favourable environment for onshore storage across Europe.
The ENOS site portfolio will provide a great opportunity for demonstration of technologies for safe and environmentally sound storage at relevant scale. Best practices will be developed using experience gained from the field experiments with the participation of local stakeholders and the lay public. This will produce improved integrated research outcomes and increase stakeholder understanding and confidence in CO2 storage. In this improved framework, ENOS will catalyse new onshore pilot and demonstration projects in new locations and geological settings across Europe, taking into account the site-specific and local socio-economic context. By developing technologies from TRL4/5 to TRL6 across the storage lifecycle, feeding the resultant knowledge and experience into training and education and cooperating at the pan-European and global level, ENOS will have a decisive impact on innovation and build the confidence needed for enabling onshore CO2 storage in Europe.
ENOS is initiating strong international collaboration between European researchers and their counterparts from the USA, Canada, South Korea, Australia and South Africa for sharing experience worldwide based on real-life onshore pilots and field experiments. Fostering experience-sharing and research alignment between existing sites is key to maximise the investment made at individual sites and to support the efficient large scale deployment of CCS. ENOS is striving to promote collaboration between sites in the world through a programme of site twinning, focus groups centered around operative issues and the creation of a leakage simulation alliance
Creep and fracture behavior of peak-aged Mg-11Y-5Gd-2Zn-0.5Zr (wt pct)
The tensile-creep and creep-fracture behavior of peak-aged Mg-11Y-5Gd-2Zn-0.5Zr (wt pct) (WGZ1152) was investigated at temperatures between 523 K (250 °C) to 598 K (325 °C) (0.58 to 0.66 T m) and stresses between 30 MPa to 140 MPa. The minimum creep rate of the alloy was almost two orders of magnitude lower than that for WE54-T6 and was similar to that for HZ32-T5. The creep behavior exhibited an extended tertiary creep stage, which was believed to be associated with precipitate coarsening. The creep stress exponent value was 4.5, suggesting that dislocation creep was the rate-controlling mechanism during secondary creep. At T = 573 K (300 °C), basal slip was the dominant deformation mode. The activation energy for creep (Q avg = 221 ± 20 kJ/mol) was higher than that for self-diffusion in magnesium and was believed to be associated with the presence of second-phase particles as well as the activation of nonbasal slip and cross slip. This finding was consistent with the slip-trace analysis and surface deformation observations, which revealed that the nonbasal slip was active. The minimum creep rate and time-to-fracture followed the original and modified Monkman-Grant relationships. The microcracks and cavities nucleated preferentially at grain boundaries and at the interface between the matrix phase and the second phase. In-situ creep experiments highlighted the intergranular cracking evolution
A survey of xerophilic Aspergillus from indoor environment, including descriptions of two new section Aspergillus species producing eurotium-like sexual states
Volume: 19Start Page: 1End Page: 3
Nanostructures Defined by The Local Oxidation of Ferromagnetic GaMnAs Layer
The results of Local Anodic Oxidation (LAO) on the thin GaMnAs layers are reported. The ferromagnetic GaMnAs layers were prepared by low temperature MBE growth in a Veeco Mod Gen II machine. The LAO process was performed with the AFM microscope Smena NT-MDT placed in the sealed box with the controlled humidity in the range 45-80%. The oxide was grown in the semi-contact mode of the AFM. Sample was positively biased with respect to the AFM tip with the bias from 6 to 24 V. The conductive diamond coated AFM tips with the radius 30 nm were utilized for the oxidation. The tip speed during the oxidation was changed from 400 nm/s to 1.5 ÎĽm/s. The tip force was also changed during the oxidation. The height of oxide nanolines increases with applied voltage from 3 to 18 nm. The width of these lines was approximately 100 nm at half of the maximum
- …