1,765 research outputs found
Self Injection length in La0.7 Ca0.3 Mno3-YBa 2Cu3O7-d ferromagnet- superconductor multi layer thin films
We have carried out extensive studies on the self-injection problem in
barrierless heterojunctions between La0.7Ca0.3MnO3 (LCMO) and YBa2Cu3O7-d
(YBCO). The heterojunctions were grown in situ by sequentially growing LCMO and
YBCO films on LaAlO3 (LAO) substrate using a pulsed laser deposition
(PLD) system. YBCO micro-bridges with 64 microns width were patterned both on
the LAO (control) and LCMO side of the substrate. Critical current, Ic, was
measured at 77K on both the control side as well as the LCMO side for different
YBCO film thickness. It was observed that while the control side showed a Jc of
~2 x 10E6 A/ cm2 the LCMO side showed about half the value for the same
thickness (1800 A). The difference in Jc indicates that a certain thickness of
YBCO has become 'effectively' normal due to self-injection. From the
measurement of Jc at two different thickness' (1800 A and 1500 A) of YBCO both
on the LAO as well as the LCMO side, the value of self-injection length (at
77K) was estimated to be ~900 A self-injection length has been quantified. A
control experiment carried out with LaNiO3 deposited by PLD on YBCO did not
show any evidence of self-injection.Comment: 6 pages, one figure in .ps forma
Dystonic opisthotonus: A "red flag" for neurodegeneration with brain iron accumulation syndromes?
Back arching was reported in one of the very first patients with neurodegeneration with brain iron accumulation syndrome (NBIAs) published in 1936. However, recent reports have mainly focused on the genetic and imaging aspects of these disorders, and the phenotypic characterization of the dystonia has been lost. In evaluating patients with NBIAs in our centers, we have observed that action-induced dystonic opisthotonus is a common and characteristic feature of NBIAs. Here, we present a case series of patients with NBIAs presenting this feature demonstrated by videos. We suggest that dystonic opisthotonus could be a useful "red flag" for clinicians to suspect NBIAs, and we discuss the differential diagnosis of this feature. This would be particularly useful in identifying patients with NBIAs and no iron accumulation as yet on brain imaging (for example, as in phospholipase A2, group IV (cytosolic, calcium-independent) [PLA2G6]-related disorders), and it has management implications.© 2013 International Parkinson and Movement Disorder Society
A global method for coupling transport with chemistry in heterogeneous porous media
Modeling reactive transport in porous media, using a local chemical
equilibrium assumption, leads to a system of advection-diffusion PDE's coupled
with algebraic equations. When solving this coupled system, the algebraic
equations have to be solved at each grid point for each chemical species and at
each time step. This leads to a coupled non-linear system. In this paper a
global solution approach that enables to keep the software codes for transport
and chemistry distinct is proposed. The method applies the Newton-Krylov
framework to the formulation for reactive transport used in operator splitting.
The method is formulated in terms of total mobile and total fixed
concentrations and uses the chemical solver as a black box, as it only requires
that on be able to solve chemical equilibrium problems (and compute
derivatives), without having to know the solution method. An additional
advantage of the Newton-Krylov method is that the Jacobian is only needed as an
operator in a Jacobian matrix times vector product. The proposed method is
tested on the MoMaS reactive transport benchmark.Comment: Computational Geosciences (2009)
http://www.springerlink.com/content/933p55085742m203/?p=db14bb8c399b49979ba8389a3cae1b0f&pi=1
The SNAPSHOT study protocol : SNAcking, Physical activity, Self-regulation, and Heart rate Over Time
Peer reviewedPublisher PD
Feasibility Study of Dual Energy Radiographic Imaging for Target Localization in Radiotherapy for Lung Tumors
Purpose
Dual-energy (DE) radiographic imaging improves tissue discrimination by separating soft from hard tissues in the acquired images. This study was to establish a mathematic model of DE imaging based on intrinsic properties of tissues and quantitatively evaluate the feasibility of applying the DE imaging technique to tumor localization in radiotherapy.
Methods
We investigated the dependence of DE image quality on the radiological equivalent path length (EPL) of tissues with two phantoms using a stereoscopic x-ray imaging unit. 10 lung cancer patients who underwent radiotherapy each with gold markers implanted in the tumor were enrolled in the study approved by the hospital's Ethics Committee. The displacements of the centroids of the delineated gross tumor volumes (GTVs) in the digitally reconstructed radiograph (DRR) and in the bone-canceled DE image were compared with the averaged displacements of the centroids of gold markers to evaluate the feasibility of using DE imaging for tumor localization.
Results
The results of the phantom study indicated that the contrast-to-noise ratio (CNR) was linearly dependent on the difference of EPL and a mathematical model was established. The objects and backgrounds corresponding to ΔEPL less than 0.08 are visually indistinguishable in the bone-canceled DE image. The analysis of patient data showed that the tumor contrast in the bone-canceled images was improved significantly as compared with that in the original radiographic images and the accuracy of tumor localization using the DE imaging technique was comparable with that of using fiducial makers.
Conclusion
It is feasible to apply the technique for tumor localization in radiotherapy
Antimetastatic Effects of Norcantharidin on Hepatocellular Carcinoma by Transcriptional Inhibition of MMP-9 through Modulation of NF-kB Activity
The rate of morbidity and mortality of hepatocellular carcinoma (HCC) in Taiwan has not lessened because of difficulty in treating tumor metastasis. Norcantharidin (NCTD) is currently used as an anticancer drug for hepatoma, breast cancer, and colorectal adenocarcinoma. NCTD possesses various biological anticancer activities, including apoptosis. However, detailed effects and molecular mechanisms of NCTD on metastasis are unclear. Thus, HCC cells were subjected to treatment with NCTD and then analyzed to determine the effects of NCTD on cell metastasis.Modified Boyden chamber assays revealed that NCTD treatment inhibited cell migration and invasion capacities of HCC cells substantially. Results of zymography and western blotting showed that activities and protein levels of matrix metalloproteinase-9 (MMP-9) and urokinase plasminogen activator (u-PA) were inhibited by NCTD. Western blot analysis showed that NCTD inhibits phosphorylation of ERK1/2. Testing of mRNA level, quantitative real-time PCR, and promoter assays evaluated the inhibitory effects of NCTD on MMP-9 and u-PA expression in HCC cells. The chromatin immunoprecipitation (ChIP) assay for analyzing the genomic DNA sequences bound to these proteins was reactive to the transcription protein nuclear factor (NF)-kappaB, which was inhibited by NCTD. The expression of NF-kappa B was measured by western blot analysis, which revealed decreased nuclear-factor DNA-binding activity after NCTD treatment.NCTD inhibited MMP-9 and u-PA expression through the phosphorylation of ERK1/2 and NF-kappaB signaling pathway which serves as a powerful chemopreventive agent in HCC cell metastasis
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Measurement of cosmic-ray muons and muon-induced neutrons in the Aberdeen Tunnel Underground Laboratory
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The association between socioeconomic status and traditional chinese medicine use among children in Taiwan
<p>Abstract</p> <p>Background</p> <p>Traditional Chinese medicine (TCM) utilization is common in Asian countries. Limited studies are available on the socioeconomic status (SES) associated with TCM use among the pediatric population. We report on the association between SES and TCM use among children and adolescents in Taiwan.</p> <p>Methods</p> <p>A National Health Interview Survey was conducted in Taiwan in 2001 that included 5,971 children and adolescents. We assessed the children's SES using the head of household's education, occupation and income. This information was used to calculate pediatric SES scores, which in turn were divided into quartiles. Children and adolescents who visited TCM in the past month were defined as TCM users.</p> <p>Results</p> <p>Compared to children in the second SES quartile, children in the fourth SES quartile had a higher average number of TCM visits (0.12 vs. 0.06 visits, p = 0.027) and higher TCM use prevalence (5.0% vs. 3.6%, p = 0.024) within the past month. The adjusted odds ratio (OR) for TCM use was higher for children in the fourth SES quartile than for those in the first SES quartile (OR 1.49; 95% confidence interval [CI] 1.02-2.17). The corresponding OR was 2.17 for girls (95% CI 1.24-3.78). The highest-SES girls (aged 10-18 years) were most likely to visit TCM practices (OR 2.47; 95% CI 1.25-4.90).</p> <p>Conclusions</p> <p>Children and adolescents with high SES were more likely to use TCM and especially girls aged 10-18 years. Our findings point to the high use of complementary and alternative medicine among children and adolescents.</p
Polymorphism in heme oxygenase-1 (HO-1) promoter is related to the risk of oral squamous cell carcinoma occurring on male areca chewers
Autoimmune and autoinflammatory mechanisms in uveitis
The eye, as currently viewed, is neither immunologically ignorant nor sequestered from the systemic environment. The eye utilises distinct immunoregulatory mechanisms to preserve tissue and cellular function in the face of immune-mediated insult; clinically, inflammation following such an insult is termed uveitis. The intra-ocular inflammation in uveitis may be clinically obvious as a result of infection (e.g. toxoplasma, herpes), but in the main infection, if any, remains covert. We now recognise that healthy tissues including the retina have regulatory mechanisms imparted by control of myeloid cells through receptors (e.g. CD200R) and soluble inhibitory factors (e.g. alpha-MSH), regulation of the blood retinal barrier, and active immune surveillance. Once homoeostasis has been disrupted and inflammation ensues, the mechanisms to regulate inflammation, including T cell apoptosis, generation of Treg cells, and myeloid cell suppression in situ, are less successful. Why inflammation becomes persistent remains unknown, but extrapolating from animal models, possibilities include differential trafficking of T cells from the retina, residency of CD8(+) T cells, and alterations of myeloid cell phenotype and function. Translating lessons learned from animal models to humans has been helped by system biology approaches and informatics, which suggest that diseased animals and people share similar changes in T cell phenotypes and monocyte function to date. Together the data infer a possible cryptic infectious drive in uveitis that unlocks and drives persistent autoimmune responses, or promotes further innate immune responses. Thus there may be many mechanisms in common with those observed in autoinflammatory disorders
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