451 research outputs found
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Insights into centriole geometry revealed by cryotomography of doublet and triplet centrioles.
Centrioles are cylindrical assemblies comprised of 9 singlet, doublet, or triplet microtubules, essential for the formation of motile and sensory cilia. While the structure of the cilium is being defined at increasing resolution, centriolar structure remains poorly understood. Here, we used electron cryo-tomography to determine the structure of mammalian (triplet) and Drosophila (doublet) centrioles. Mammalian centrioles have two distinct domains: a 200 nm proximal core region connected by A-C linkers, and a distal domain where the C-tubule is incomplete and a pair of novel linkages stabilize the assembly producing a geometry more closely resembling the ciliary axoneme. Drosophila centrioles resemble the mammalian core, but with their doublet microtubules linked through the A tubules. The commonality of core-region length, and the abrupt transition in mammalian centrioles, suggests a conserved length-setting mechanism. The unexpected linker diversity suggests how unique centriolar architectures arise in different tissues and organisms
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Association of Systemic Inflammation With Retinal Vascular Caliber in Patients With AIDS.
PurposeTo evaluate relationships among retinal vascular caliber and biomarkers of systemic inflammation in patients with AIDS.MethodsA total of 454 participants with AIDS had retinal vascular caliber (central retinal artery equivalent and central retinal vein equivalent) determined from enrollment retinal photographs by reading center graders masked to clinical and biomarker information. Cryopreserved plasma specimens were assayed for inflammatory biomarkers, including C-reactive protein (CRP), IL-6, interferon-γ inducible protein (IP)-10, kynurenine/tryptophan (KT) ratio, and intestinal fatty acid binding protein (I-FABP).ResultsIn the simple linear regression of retinal vascular caliber on plasma biomarkers, elevated CRP, IL-6, and IP-10 were associated with retinal venular dilation, and elevated KT ratio with retinal arteriolar narrowing. In the multiple linear regression, including baseline characteristics and plasma biomarkers, AMD was associated with dilation of retinal arterioles (mean difference: 9.1 μm; 95% confidence interval [CI] 5.2, 12.9; P < 0.001) and venules (mean difference, 10.9 μm; 95% CI, 5.3, 16.6; P < 0.001), as was black race (P < 0.001). Hyperlipidemia was associated with retinal venular narrowing (mean difference, -7.5 μm; 95% CI, -13.7, -1.2; P = 0.02); cardiovascular disease with arteriolar narrowing (mean difference, -5.2 μm; 95% CI, -10.3, -0.1; P = 0.05); age with arteriolar narrowing (slope, -0.26 μm/year; 95% CI, -0.46, -0.06; P = 0.009); and IL-6 with venular dilation (slope, 5.3 μm/standard deviation log10[plasma IL-6 concentration]; 95% CI, 2.7, 8.0; P < 0.001).ConclusionsThese data suggest that retinal vascular caliber is associated with age, race, AMD, hyperlipidemia, cardiovascular disease, and selected biomarkers of systemic inflammation
Utilization of Additive Manufacturing for the Rapid Prototyping of C-Band RF Loads
Additive manufacturing is a versatile technique that shows promise in
providing quick and dynamic manufacturing for complex engineering problems.
Research has been ongoing into the use of additive manufacturing for potential
applications in radiofrequency (RF) component technologies. Here we present a
method for developing an effective prototype load produced out of 316L
stainless steel on a direct metal laser sintering machine. The model was tested
within simulation software to verify the validity of the design. The load
structure was manufactured utilizing an online digital manufacturing company,
showing the viability of using easily accessible tools to manufacture RF
structures. The produced load was able to produce an S value of -22.8 dB
at the C-band frequency of 5.712 GHz while under vacuum. In a high power test,
the load was able to terminate a peak power of 8.1 MW. Discussion includes
future applications of the present research and how it will help to improve the
implementation of future accelerator concepts
Irradiated Human Endothelial Progenitor Cells Induce Bystander Killing in Human Non-Small Cell Lung and Pancreatic Cancer Cells
Purpose
To investigate whether irradiated human endothelial progenitor cells (hEPCs) could induce bystander killing in the A549 non-small cell lung cancer (NSCLC) cells and help explain the improved radiation-induced tumor cures observed in A549 tumor xenografts co-injected with hEPCs.
Materials and Methods
We investigated whether co-injection of CBM3 hEPCs with A549 NSCLC cells would alter tumor xenograft growth rate or tumor cure after a single dose of 0 or 5 Gy of X-rays. We then utilized dual chamber Transwell dishes, to test whether medium from irradiated CBM3 and CBM4 hEPCs would induce bystander cell killing in A549 cells, and as an additional control, in human pancreatic cancer MIA PaCa-2 cells. The CBM3 and CBM4 hEPCs were plated into the upper Transwell chamber and the A549 or MIA PaCa-2 cells were plated in the lower Transwell chamber. The top inserts with the CBM3 or CBM4 hEPCs cells were subsequently removed, irradiated, and then placed back into the Transwell dish for 3 h to allow for diffusion of any potential bystander factors from the irradiated hEPCs in the upper chamber through the permeable membrane to the unirradiated cancer cells in the lower chamber. After the 3 h incubation, the cancer cells were re-plated for clonogenic survival.
Results
We found that co-injection of CBM3 hEPCs with A549 NSCLC cells significantly increased the tumor growth rate compared to A549 cells alone, but paradoxically also increased A549 tumor cure after a single dose of 5 Gy of X-rays (P < 0.05). We hypothesized that irradiated hEPCs may be inducing bystander killing in the A549 NSCLC cells in tumor xenografts, thus improving tumor cure. Bystander studies clearly showed that exposure to the medium from irradiated CBM3 and CBM4 hEPCs induced significant bystander killing and decreased the surviving fraction of A549 and MIA PaCa-2 cells to 0.46 (46%) ± 0.22 and 0.74 ± 0.07 (74%) respectively (P < 0.005, P < 0.0001). In addition, antibody depletion studies demonstrated that the bystander killing induced in both A549 and MIA PaCa-2 cells was mediated by the cytokines TNF-α and TGF-β (P < 0.05).
Conclusions
These data provide evidence that irradiated hEPCs can induce strong bystander killing in A549 and MIA PaCa-2 human cancer cells and that this bystander killing is mediated by the cytokines TNF-α and TGF-β
Radio Observations of the Hubble Deep Field South region: I. Survey Description and Initial Results
This paper is the first of a series describing the results of the Australia
Telescope Hubble Deep Field South (ATHDFS) radio survey. The survey was
conducted at four wavelengths - 20, 11, 6, and 3 cm, over a 4-year period, and
achieves an rms sensitivity of about 10 microJy at each wavelength. We describe
the observations and data reduction processes, and present data on radio
sources close to the centre of the HDF-S. We discuss in detail the properties
of a subset of these sources. The sources include both starburst galaxies and
galaxies powered by an active galactic nucleus, and range in redshift from 0.1
to 2.2. Some of them are characterised by unusually high radio-to-optical
luminosities, presumably caused by dust extinction.Comment: Accepted by AJ. 32 pages, 4 tables, 3 figures. PDF with
full-resolution figures is on
http://www.atnf.csiro.au/people/rnorris/N197.pd
The Influence of LO Power Heating of the Tunnel Junction on the Performance of THz SIS Mixers
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Levantamento dos potenciais não madeireiros de espécies arbóreas em propriedades rurais de Fernandes Pinheiro, PR: Assessment of the nontimber potential of tree species on rural properties in Fernandes Pinheiro, PR
O termo “sustentabilidade” já está aliado em diversos setores de produção, cujo intuito é explorar os recursos naturais de forma que haja uma minimização dos impactos ambientais gerados pelo processo empregado. No Paraná, as florestas com Araucárias foram amplamente exploradas e pouca relevância foi atribuída aos produtos considerados não madeireiros. De acordo com a FAO (1995), pelo menos 150 PFNM têm significado no comércio internacional. Desta maneira, o objetivo do presente trabalho foi avaliar qualitativamente os potenciais não madeireiros das espécies catalogadas em um Inventário Florestal realizado em fragmentos de Floresta Ombrófila Mista (FOM) em pequenas propriedades rurais na comunidade de Assungui da cidade de Fernandes Pinheiro, Paraná, bem como classifica-las em categorias de usos e possíveis recomendações para enriquecimento de áreas de reserva legal para uma exploração de subprodutos. De acordo com o levantamento florístico foram registradas 107 espécies de caráter florestal distribuídas em 39 famílias botânicas. Destas, 64 espécies com potencial não madeireiro foram amostradas representando 59,81% do total registrado, conferindo uma ampla diversidade de produtos e utilizações. Essas espécies foram estruturadas em categorias de usos sendo a classe medicinal a mais representativa com 49,28% do total amostrado, seguido de ornamental (42,8%), melífera (33,17%), alimentícia (22,47%), forrageira (13,91%), fornecedora de taninos (10,7%), fibras (5,35%), resinas (5,35%), dentre outras categorias menos representativas em número de espécies. Das espécies amostradas, uma porção representativa possui ao menos uma propriedade não madeireira. Assim, através de enriquecimentos de áreas de reserva legal com espécies pré-determinadas, pode se contribuir para a restauração de ecossistemas e diversificação de renda de produtores rurais familiares
International Coercion, Emulation and Policy Diffusion: Market-Oriented Infrastructure Reforms, 1977-1999
Why do some countries adopt market-oriented reforms such as deregulation, privatization and liberalization of competition in their infrastructure industries while others do not? Why did the pace of adoption accelerate in the 1990s? Building on neo-institutional theory in sociology, we argue that the domestic adoption of market-oriented reforms is strongly influenced by international pressures of coercion and emulation. We find robust support for these arguments with an event-history analysis of the determinants of reform in the telecommunications and electricity sectors of as many as 205 countries and territories between 1977 and 1999. Our results also suggest that the coercive effect of multilateral lending from the IMF, the World Bank or Regional Development Banks is increasing over time, a finding that is consistent with anecdotal evidence that multilateral organizations have broadened the scope of the “conditionality” terms specifying market-oriented reforms imposed on borrowing countries. We discuss the possibility that, by pressuring countries into policy reform, cross-national coercion and emulation may not produce ideal outcomes.http://deepblue.lib.umich.edu/bitstream/2027.42/40099/3/wp713.pd
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International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci.
The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations
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Fast-neutron-induced fission studied by gamma-spectroscopy.
Prompt gamma-ray and x-ray spectroscopy techniques are being employed to study fast-neutron-induced fission of actinides to determine independent (pre-beta-decay) yields for a wide range of product nuclides. Data are acquired using the GEANIE high-resolution gamma-ray spectrometer at the LANSCE/WNR unmoderated spallation neutron source providing neutrons with energies from below 1 MeV to over 400 MeV. Three different techniques (identification by characteristic gamma rays, by gamma-gamma coincidences, and by fission-gamma coincidences) are being used to gather complementary data sets from which detailed fission yields can be extracted. From these data, mass and charge distributions are determined over a wide incident-neutron energy range. The phenomena of interest include the transition from asymmetric to symmetric fission, the competition between neutron and gamma-ray emission, nuclear structure effects in fission and the angular momentum imparted to the fission products. Results for 238U and 236U are presented
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