98 research outputs found
Ion beam synthesis of nanothermochromic diffraction gratings with giant switching contrast at telecom wavelengths
Nanothermochromic diffraction gratings based on the metal-insulator
transition of are fabricated by site-selective ion beam
implantation in a matrix. Gratings were defined either (i)
directly by spatially selective ion beam synthesis or (ii) by site-selective
deactivation of the phase transition by ion beam induced defects. The strongest
increase of the diffracted light intensities was observed at a wavelength of
1550\,nm exceeding a factor of 20 for the selectively deactivated gratings. The
observed pronounced thermal hysteresis extending down close to room temperature
makes this system ideally suited for optical memory applications.Comment: 4 pages, 3 figures, 1 table - corrected Figure
Space Shuttle Program: Automatic rendezvous, proximity operations, and capture (category 3)
The NASA Johnson Space Center is actively pursuing the development and demonstration of capabilities for automatic rendezvous, proximity operations, and capture (AR&C) using the Space Shuttle as the active vehicle. This activity combines the technologies, expertise, tools, and facilities of the JSC Tracking and Communications Division (EE), Navigation, Control and Aeronautics Division (EG), Automation and Robotics Division (ER), and Structures and Mechanics Division (ES) of the Engineering Directorate and the Flight Design and Dynamics Division (DM) of the Mission Operations Directorate. Potential benefits of AR&C include more efficient and repeatable rendezvous, proximity operations, and capture operations; reduced impacts on the target vehicles (e.g., Orbiter RCS plume loads); reduced flight crew work loads; reduced ground support requirements; and reduced operational constraints. This paper documents the current JSC capabilities/tools/facilities for AR&C and describes a proposed plan for a progression of ground demonstrations and flight tests and demonstrations of AR&C capabilities. This plan involves the maturing of existing technologies in tracking and communications; guidance, navigation and control; mechanisms; manipulators; and systems management and integrating them into several evolutionary demonstration stages
Studies on the clinical significance of nonesterified and total cholesterol in urine
Gas-liquid chromatographic determinations of nonesterified and total urinary cholesterol were performed in 137 normals, 264 patients with various internal diseases without evidence of neoplasias or diseases of the kidney or urinary tract, 497 patients with malignancies and 236 patients with diseases of the kidney, urinary tract infections or prostatic adenoma with residual urine. A normal range (mean±2 SD) of 0.2–2.2 mg/24 hours nonesterified cholesterol (NEC) and of 0.3–3.0 mg/24 hours total cholesterol (TC) was calculated.
Values of urinary cholesterol excretion were independent of age and sex and did not correlate with cholesterol levels in plasma. Patients with various internal diseases, without evidence of neoplasias nor diseases of the kidney or obstruction of the urinary tract, showed normal urinary cholesterol excretions, as did patients with infections of the urinary tract.
However, elevated urinary cholesterol was found in patients with diseases of the kidney or urinary tract obstruction (prostatic adenoma with residual urine), malignant diseases of the urogenital tract and metastasing carcinoma of the breast. In patients with other malignant diseases urinary cholesterol was usually normal.
Lesions of the urothelial cell membranes are considered to be the most likely cause of urinary cholesterol hyperexcretion. The clinical value of urinary cholesterol determinations as a possible screening test for urogenital carcinomas in unselected populations is limited by lacking specificity, expensive methodology and low prevalence of the mentioned carcinomas, although elevated urinary cholesterol excretions have been observed in early clinical stages of urogenital cancers
Magnetic Field Structure of the Large Magellanic Cloud from Faraday Rotation Measures of Diffuse Polarized Emission
We present a study of the magnetic field of the Large Magellanic Cloud (LMC),
carried out using diffuse polarized synchrotron emission data at 1.4 GHz
acquired at the Parkes Radio Telescope and the Australia Telescope Compact
Array. The observed diffuse polarized emission is likely to originate above the
LMC disk on the near side of the galaxy. Consistent negative rotation measures
(RMs) derived from the diffuse emission indicate that the line-of-sight
magnetic field in the LMC's near-side halo is directed coherently away from us.
In combination with RMs of extragalactic sources that lie behind the galaxy, we
show that the LMC's large scale magnetic field is likely to be of quadrupolar
geometry, consistent with the prediction of dynamo theory. On smaller scales,
we identify two brightly polarized filaments southeast of the LMC, associated
with neutral hydrogen arms. The filaments' magnetic field potentially aligns
with the direction towards the Small Magellanic Cloud. We suggest that tidal
interactions between the Small and the Large Magellanic Clouds in the past 10^9
years is likely to have shaped the magnetic field in these filaments.Comment: 42 pages, 22 figures, 2 tables. Accepted for publication in ApJ.
Electronic version of Table 2 is available via email from the first autho
Preserving the impossible: conservation of soft-sediment hominin footprint sites and strategies for three-dimensional digital data capture.
Human footprints provide some of the most publically emotive and tangible evidence of our ancestors. To the scientific community they provide evidence of stature, presence, behaviour and in the case of early hominins potential evidence with respect to the evolution of gait. While rare in the geological record the number of footprint sites has increased in recent years along with the analytical tools available for their study. Many of these sites are at risk from rapid erosion, including the Ileret footprints in northern Kenya which are second only in age to those at Laetoli (Tanzania). Unlithified, soft-sediment footprint sites such these pose a significant geoconservation challenge. In the first part of this paper conservation and preservation options are explored leading to the conclusion that to 'record and digitally rescue' provides the only viable approach. Key to such strategies is the increasing availability of three-dimensional data capture either via optical laser scanning and/or digital photogrammetry. Within the discipline there is a developing schism between those that favour one approach over the other and a requirement from geoconservationists and the scientific community for some form of objective appraisal of these alternatives is necessary. Consequently in the second part of this paper we evaluate these alternative approaches and the role they can play in a 'record and digitally rescue' conservation strategy. Using modern footprint data, digital models created via optical laser scanning are compared to those generated by state-of-the-art photogrammetry. Both methods give comparable although subtly different results. This data is evaluated alongside a review of field deployment issues to provide guidance to the community with respect to the factors which need to be considered in digital conservation of human/hominin footprints
The role of macrophage-inducible C-type lectin in different stages of chronic liver disease
The macrophage-inducible C-type lectin (mincle) is part of the innate immune system and acts as a pattern recognition receptor for pathogen-associated molecular patterns (PAMPS) and damage-associated molecular patterns (DAMPs). Ligand binding induces mincle activation which consequently interacts with the signaling adapter Fc receptor, SYK, and NF-kappa-B. There is also evidence that mincle expressed on macrophages promotes intestinal barrier integrity. However, little is known about the role of mincle in hepatic fibrosis, especially in more advanced disease stages. Mincle expression was measured in human liver samples from cirrhotic patients and donors collected at liver transplantation and in patients undergoing bariatric surgery. Human results were confirmed in rodent models of cirrhosis and acute-on-chronic liver failure (ACLF). In these models, the role of mincle was investigated in liver samples as well as in peripheral blood monocytes (PBMC), tissues from the kidney, spleen, small intestine, and heart. Additionally, mincle activation was stimulated in experimental non-alcoholic steatohepatitis (NASH) by treatment with mincle agonist trehalose-6,6-dibehenate (TDB). In human NASH, mincle is upregulated with increased collagen production. In ApoE deficient mice fed high-fat western diet (NASH model), mincle activation significantly increases hepatic collagen production. In human cirrhosis, mincle expression is also significantly upregulated. Furthermore, mincle expression is associated with the stage of chronic liver disease. This could be confirmed in rat models of cirrhosis and ACLF. ACLF was induced by LPS injection in cirrhotic rats. While mincle expression and downstream signaling via FC receptor gamma, SYK, and NF-kappa-B are upregulated in the liver, they are downregulated in PBMCs of these rats. Although mincle expressed on macrophages might be beneficial for intestinal barrier integrity, it seems to contribute to inflammation and fibrosis once the intestinal barrier becomes leaky in advanced stages of chronic liver disease
A review of Australian Government funding of parenting intervention research
Objectives: Parenting is central to children's optimal development and accounts for a substantial proportion of the variance in child outcomes, including up to 40% of child mental health. Parenting is also one of the most modifiable, proximal, and direct factors for preventing and treating a range of children's problems and enhancing wellbeing. To determine the effectiveness of new approaches to parenting intervention, and to evaluate how to optimise reach and uptake, sufficient funding must be allocated for high quality research. Method: We reviewed funding awarded by the National Health and Medical Research Council (NHMRC) and Australian Research Council (ARC) for parenting intervention research during 2011–2020. Results: Parenting intervention research received 0.25% of the NHMRC and ARC research budgets. Conclusions: There is a substantial mismatch between the funding of parenting intervention research and the impact of improved parenting on short- and long-term child outcomes. To rectify this, it is critical that Australian Government funding schemes include parenting interventions as priority areas for funding. Implications for public health: Changes in allocation of funding to parenting research will support the establishment of evidence for the effective development, implementation and dissemination of parenting interventions to maximise health outcomes for children and their families.</p
RNAi-mediated suppression of isoprene emission in poplar transiently impacts phenolic metabolism under high temperature and high light intensities: a transcriptomic and metabolomic analysis
In plants, isoprene plays a dual role: (a) as thermo-protective agent proposed to prevent degradation of enzymes/membrane structures involved in photosynthesis, and (b) as reactive molecule reducing abiotic oxidative stress. The present work addresses the question whether suppression of isoprene emission interferes with genome wide transcription rates and metabolite fluxes in grey poplar (Populusxcanescens) throughout the growing season. Gene expression and metabolite profiles of isoprene emitting wild type plants and RNAi-mediated non-isoprene emitting poplars were compared by using poplar Affymetrix microarrays and non-targeted FT-ICR-MS (Fourier transform ion cyclotron resonance mass spectrometry). We observed a transcriptional down-regulation of genes encoding enzymes of phenylpropanoid regulatory and biosynthetic pathways, as well as distinct metabolic down-regulation of condensed tannins and anthocyanins, in non-isoprene emitting genotypes during July, when high temperature and light intensities possibly caused transient drought stress, as indicated by stomatal closure. Under these conditions leaves of non-isoprene emitting plants accumulated hydrogen peroxide (H2O2), a signaling molecule in stress response and negative regulator of anthocyanin biosynthesis. The absence of isoprene emission under high temperature and light stress resulted transiently in a new chemo(pheno)type with suppressed production of phenolic compounds. This may compromise inducible defenses and may render non-isoprene emitting poplars more susceptible to environmental stress
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