5,774 research outputs found
The role of rapid solidification processing in the fabrication of fiber reinforced metal matrix composites
Advanced composite processing techniques for fiber reinforced metal matrix composites require the flexibility to meet several widespread objectives. The development of uniquely desired matrix microstructures and uniformly arrayed fiber spacing with sufficient bonding between fiber and matrix to transmit load between them without degradation to the fiber or matrix are the minimum requirements necessary of any fabrication process. For most applications these criteria can be met by fabricating composite monotapes which are then consolidated into composite panels or more complicated components such as fiber reinforced turbine blades. Regardless of the end component, composite monotapes are the building blocks from which near net shape composite structures can be formed. The most common methods for forming composite monotapes are the powder cloth, foil/fiber, plasma spray, and arc spray processes. These practices, however, employ rapid solidification techniques in processing of the composite matrix phase. Consequently, rapid solidification processes play a vital and yet generally overlooked role in composite fabrication. The future potential of rapid solidification processing is discussed
Mitochondrial plasmids of the pCp family are spread worldwide in Cryphonectria parasitica populations
Development of Wireless Techniques in Data and Power Transmission - Application for Particle Physics Detectors
Wireless techniques have developed extremely fast over the last decade and
using them for data and power transmission in particle physics detectors is not
science- fiction any more. During the last years several research groups have
independently thought of making it a reality. Wireless techniques became a
mature field for research and new developments might have impact on future
particle physics experiments. The Instrumentation Frontier was set up as a part
of the SnowMass 2013 Community Summer Study [1] to examine the instrumentation
R&D for the particle physics research over the coming decades: {\guillemotleft}
To succeed we need to make technical and scientific innovation a priority in
the field {\guillemotright}. Wireless data transmission was identified as one
of the innovations that could revolutionize the transmission of data out of the
detector. Power delivery was another challenge mentioned in the same report. We
propose a collaboration to identify the specific needs of different projects
that might benefit from wireless techniques. The objective is to provide a
common platform for research and development in order to optimize effectiveness
and cost, with the aim of designing and testing wireless demonstrators for
large instrumentation systems
The ‘ForensOMICS’ approach for postmortem interval estimation from human bone by integrating metabolomics, lipidomics, and proteomics
The combined use of multiple omics allows to study complex interrelated biological processes in their entirety. We applied a combination of metabolomics, lipidomics and proteomics to human bones to investigate their combined potential to estimate time elapsed since death (i.e., the postmortem interval [PMI]). This 'ForensOMICS' approach has the potential to improve accuracy and precision of PMI estimation of skeletonized human remains, thereby helping forensic investigators to establish the timeline of events surrounding death. Anterior midshaft tibial bone was collected from four female body donors before their placement at the Forensic Anthropology Research Facility owned by the Forensic Anthropological Center at Texas State (FACTS). Bone samples were again collected at selected PMIs (219-790-834-872days). Liquid chromatography mass spectrometry (LC-MS) was used to obtain untargeted metabolomic, lipidomic, and proteomic profiles from the pre- and post-placement bone samples. The three omics blocks were investigated independently by univariate and multivariate analyses, followed by Data Integration Analysis for Biomarker discovery using Latent variable approaches for Omics studies (DIABLO), to identify the reduced number of markers describing postmortem changes and discriminating the individuals based on their PMI. The resulting model showed that pre-placement metabolome, lipidome and proteome profiles were clearly distinguishable from post-placement ones. Metabolites in the pre-placement samples suggested an extinction of the energetic metabolism and a switch towards another source of fuelling (e.g., structural proteins). We were able to identify certain biomolecules with an excellent potential for PMI estimation, predominantly the biomolecules from the metabolomics block. Our findings suggest that, by targeting a combination of compounds with different postmortem stability, in the future we could be able to estimate both short PMIs, by using metabolites and lipids, and longer PMIs, by using proteins
A systematic study of \ce{CO2} planetary atmospheres and their link to the stellar environment
The Milky Way Galaxy is literally teeming with exoplanets; thousands of
planets have been discovered, with thousands more planet candidates identified.
Terrestrial-like planets are quite common around other stars, and are expected
to be detected in large numbers in the future. Such planets are the primary
targets in the search for potentially habitable conditions outside the solar
system.
Determining the atmospheric composition of exoplanets is mandatory to
understand their origin and evolution, as atmospheric processes play crucial
roles in many aspects of planetary architecture. In this work we construct and
exploit a 1D radiative transfer model based on the discrete-ordinates method in
plane-parallel geometry. Radiative results are linked to a convective flux that
redistributes energy at any altitude producing atmospheric profiles in
radiative-convective equilibrium. The model has been applied to a large number
(6250) of closely dry synthetic \ce{CO2} atmospheres, and the resulting
pressure and thermal profiles have been interpreted in terms of parameter
variability. Although less accurate than 3D general circulation models, not
properly accounting for e.g., clouds and atmospheric and ocean dynamics, 1D
descriptions are computationally inexpensive and retain significant value by
allowing multidimensional parameter sweeps with relative ease.Comment: 12 pages, 9 figures, accepted for publication in MNRA
Autophagy-related protein LC3 and Beclin-1 in the first trimester of pregnancy
Autophagy is a degradation process that acts in response to environmental stressors. Recently, autophagy has been detected in normal term,
preeclamptic and intrauterine growth-restricted placentas. The object of this work was to investigate the presence of autophagy in first trimester
voluntary interruption of pregnancy placental villi by the expression of autophagy-related proteins, light chain 3 (LC3), and Beclin-1. In first
trimester placental villi laser scanning confocal microscopy (LSCM) analysis revealed LC3 and Beclin-1 immunoreactivity prevalently located in
villous cytotrophoblasts. Using LSCM, LC3, and Beclin-1 were localized to the cytoplasm of the trophoblast layer in human full-term placentas.
Beclin-1 expression and LC3 activation were confirmed by western blotting. These data emphasize that autophagy activation is different
among cytotrophoblasts and syncytiotrophoblasts depending on the gestational age and thus we speculate that autophagy might play a prosurvival
role throughout human pregnancy
Microstructure and Phase Stability of Single Crystal NiAl Alloyed with Hf and Zr
Six near stoichiometric, NiAl single-crystal alloys, with 0.05-1.5 at.% of Hf and Zr additions plus Si impurities, were microstructurally analyzed in the as-cast, homogenized, and aged conditions. Hafnium-rich interdendritic regions, containing the Heusler phase (Ni2AlHf), were found in all the as-cast alloys containing Hf. Homogenization heat treatments partially reduced these interdendritic segregated regions. Transmission electron microscopy (TEM) observations of the as-cast and homogenized microstructures revealed the presence of a high density of fine Hf (or Zr) and Si-rich precipitates. These were identified as G-phase, Nil6X6Si7, or as an orthorhombic NiXSi phase, where X is Hf or Zr. Under these conditions the expected Heusler phase (beta') was almost completely absent. The Si responsible for the formation of the G and NiHfSi phases is the result of molten metal reacting with the Si-containing crucible used during the casting process. Varying the cooling rates after homogenization resulted in the refinement or complete suppression of the G and NiHfSi phases. In some of the alloys studied, long-term aging heat treatments resulted in the formation of Heusler precipitates, which were more stable at the aging temperature and coarsened at the expense of the G-phase. In other alloys, long-term aging resulted in the formation of the NiXSi phase. The stability of the Heusler or NiXSi phases can be traced to the reactive element (Hf or Zr) to silicon ratio. If the ratio is high, then the Heusler phase appears stable after long time aging. If the ratio is low, then the NiHfSi phase appears to be the stable phase
Precipitation Model Validation in 3rd Generation Aeroturbine Disc Alloys
In support of application of the DARPA-AIM methodology to the accelerated hybrid thermal process optimization of 3rd generation aeroturbine disc alloys with quantified uncertainty, equilibrium and diffusion couple experiments have identified available fundamental thermodynamic and mobility databases of sufficient accuracy. Using coherent interfacial energies quantified by Single-Sensor DTA nucleation undercooling measurements, PrecipiCalc(TM) simulations of nonisothermal precipitation in both supersolvus and subsolvus treated samples show good agreement with measured gamma particle sizes and compositions. Observed longterm isothermal coarsening behavior defines requirements for further refinement of elastic misfit energy and treatment of the parallel evolution of incoherent precipitation at grain boundaries
Constraints on the mass and atmospheric composition and evolution of the low-density young planet DS Tuc A b
We performed a radial velocity (RV) monitoring of the 40 Myr old star DS Tuc
A with HARPS at the ESO-3.6m to determine the planetary mass of its 8.14-days
planet, first revealed by TESS. We also observed two planetary transits with
HARPS and ESPRESSO at ESO-VLT, to measure the Rossiter-McLaughlin (RM) effect
and characterise the planetary atmosphere. We measured the high-energy emission
of the host with XMM observations to investigate models for atmospheric
evaporation. We employed Gaussian Processes (GP) regression to model the high
level of the stellar activity, which is more than 40 times larger than the
expected RV planetary signal. We extracted the transmission spectrum of DS Tuc
A b from the ESPRESSO data and searched for atmospheric elements/molecules
either by single-line retrieval and by performing cross-correlation with a set
of theoretical templates. Through a set of simulations, we evaluated different
scenarios for the atmospheric photo-evaporation of the planet induced by the
strong XUV stellar irradiation. While the stellar activity prevented us from
obtaining a clear detection of the planetary signal from the RVs, we set a
robust mass upper limit of 14.4 M_e for DS Tuc A b. We also confirm that the
planetary system is almost (but not perfectly) aligned. The strong level of
stellar activity hampers the detection of any atmospheric compounds, in line
with other studies presented in the literature. The expected evolution of DS
Tuc A b from our grid of models indicates that the planetary radius after the
photo-evaporation phase will fall within the Fulton gap. The comparison of the
available parameters of known young transiting planets with the distribution of
their mature counterpart confirms that the former are characterised by a low
density, with DS Tuc A b being one of the less dense.Comment: 24 pages, 19 figures, Accepted for publication on Astronomy and
Astrophysic
Phase I study on docetaxel and ifosfamide in patients with advanced solid tumours.
Docetaxel and ifosfamide have shown significant activity against a variety of solid tumours. This prompted a phase I trial on the combination of these drugs. This phase I study was performed to assess the feasibility of the combination, to determine the maximum tolerated dose (MTD) and the side effects, and to propose a safe schedule for further phase II studies. A total of 34 patients with a histologically confirmed solid tumour, who were not pretreated with taxanes or ifosfamide and who had received no more than one line of chemotherapy for advanced disease were entered into the study. Treatment consisted of docetaxel given as a 1-h infusion followed by ifosfamide as a 24-h infusion (schedule A), or ifosfamide followed by docetaxel (schedule B) every 3 weeks. Docetaxel doses ranged from 60 to 85 mg m(-2) and ifosfamide doses from 2.5 to 5.0 g m(-2). Granulocytopenia grade 3 and 4 were common (89%), short lasting and ifosfamide dose dependent. Febrile neutropenia and sepsis occurred in 17% and 2% of courses respectively. Non-haematological toxicities were mild to moderate and included alopecia, nausea, vomiting, mucositis, diarrhoea, sensory neuropathy, skin and nail toxicity and oedema. There did not appear to be any pharmacokinetic interaction between docetaxel and ifosfamide. One complete response (CR) (soft tissue sarcoma) and two partial responses (PRs) were documented. A dose of 75 mg m(-2) of docetaxel combined with 5.0 g m(-2) ifosfamide appeared to be manageable. Schedule A was advocated for further treatment
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