1,517 research outputs found

    Ultrasonic Phased Array Simulations of Welded Components at NASA

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    Comprehensive and accurate inspections of welded components have become of increasing importance as NASA develops new hardware such as Ares rocket segments for future exploration missions. Simulation and modeling will play an increasing role in the future for nondestructive evaluation in order to better understand the physics of the inspection process, to prove or disprove the feasibility for an inspection method or inspection scenario, for inspection optimization, for better understanding of experimental results, and for assessment of probability of detection. This study presents simulation and experimental results for an ultrasonic phased array inspection of a critical welded structure important for NASA future exploration vehicles. Keywords: nondestructive evaluation, computational simulation, ultrasonics, weld, modeling, phased arra

    Ultrasonic Phased Array Inspection Simulations of Welded Components at NASA

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    Comprehensive and accurate inspections of welded components have become of increasing importance as NASA develops new hardware such as Ares rocket segments for future exploration missions. Simulation and modeling will play an increased role in the future for nondestructive evaluation in order to better understand the physics of the inspection process and help explain the experimental results. It will also help to prove or disprove the feasibility for an inspection method or inspection scenario, help optimize inspections, and allow to a first approximation limits of detectability. This study presents simulation and experimental results for an ultrasonic phased array inspection of a critical welded structure important for NASA future exploration vehicles

    Ultrasonic Phased Array Inspection for an Isogrid Structural Element with Cracks

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    In this investigation, a T-shaped aluminum alloy isogrid stiffener element used in aerospace applications was inspected with ultrasonic phased array methods. The isogrid stiffener element had various crack configurations emanating from bolt holes. Computational simulation methods were used to mimic the experiments in order to help understand experimental results. The results of this study indicate that it is at least partly feasible to interrogate this type of geometry with the given flaw configurations using phased array ultrasonics. The simulation methods were critical in helping explain the experimental results and, with some limitation, can be used to predict inspection results

    Identification of Hypoxia-Regulated Proteins Using MALDI-Mass Spectrometry Imaging Combined with Quantitative Proteomics

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    Hypoxia is present in most solid tumors and is clinically correlated with increased metastasis and poor patient survival. While studies have demonstrated the role of hypoxia and hypoxia-regulated proteins in cancer progression, no attempts have been made to identify hypoxia-regulated proteins using quantitative proteomics combined with MALDI-mass spectrometry imaging (MALDI-MSI). Here we present a comprehensive hypoxic proteome study and are the first to investigate changes in situ using tumor samples. In vitro quantitative mass spectrometry analysis of the hypoxic proteome was performed on breast cancer cells using stable isotope labeling with amino acids in cell culture (SILAC). MS analyses were performed on laser-capture microdissected samples isolated from normoxic and hypoxic regions from tumors derived from the same cells used in vitro. MALDI-MSI was used in combination to investigate hypoxia-regulated protein localization within tumor sections. Here we identified more than 100 proteins, both novel and previously reported, that were associated with hypoxia. Several proteins were localized in hypoxic regions, as identified by MALDI-MSI. Visualization and data extrapolation methods for the in vitro SILAC data were also developed, and computational mapping of MALDI-MSI data to IHC results was applied for data validation. The results and limitations of the methodologies described are discussed. 2014 American Chemical Societ

    Renal cell carcinoma metastasis to the ciliary body responds to proton beam radiotherapy: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>We report an unexpected presentation of metastatic renal cell carcinoma (RCC) to the ciliary body and an interesting response to proton beam radiotherapy.</p> <p>Case presentation</p> <p>We encountered a case of angle-closure glaucoma as the initial presentation of ocular metastasis to the ciliary body in a 65-year-old Caucasian man who had undergone right radical nephrectomy for RCC 15 years earlier. He underwent YAG (yttrium aluminium garnet) laser peripheral iridotomy while further metastatic workup took place. His condition was eventually diagnosed as stage IV metastatic RCC of the clear cell type and involved multiple sites, including the ciliary body, brain, lungs, liver, and pancreas. The progression of RCC metastasis to the ciliary body was studied for 16 months. The ciliary body mass continued to grow despite systemic treatment with temsirolimus and interleukin-2 and intravitreal injections of bevacizumab. The tumor size peaked at 6.11 × 6.06 mm before the start of proton therapy, which reduced the tumor size to 5.07 × 4.39 mm.</p> <p>Conclusions</p> <p>RCC can produce metastases involving unusual sites many years after resection of the primary tumor. Proton therapy was found to be effective in treating RCC metastasis to the ciliary body in settings in which other treatment modalities failed.</p

    Pharmacogenomic and structural analysis of constitutive G-protein coupled receptor activity

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    Premi a l'excel·lència investigadora. Àmbit de les Ciències de la Salut. 2008G-protein coupled receptors (GPCRs) respond to a chemically diverse plethora of signal transduction molecules. The notion that GPCRs also signal without an external chemical trigger, i.e. in a constitutive or spontaneous manner, resulted in a paradigm shift in the field of GPCR pharmacology. With the recognition of constitutive GPCR activity and the fact that GPCR binding and signaling can be strongly affected by a single point mutation, GPCR pharmacogenomics obtained a lot of attention. For a variety of GPCRs, point mutations have been convincingly linked to human disease. Mutations within conserved motifs, known to be involved in GPCR activation, might explain the properties of some naturally occurring constitutively active GPCR variants linked to disease. A brief history historical introduction to the present concept of constitutive receptor activity is given and the pharmacogenomic and the structural aspects of constitutive receptor activity are described

    Discovery of a novel member of the histamine receptor family

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    We report the discovery, tissue distribution and pharmacological characterization of a novel receptor, which we have named H4. Like the three histamine receptors reported previously (H1, H2, and H3), the H4 receptor is a G protein-coupled receptor and is most closely related to the H3 receptor, sharing 58% identity in the transmembrane regions. The gene encoding the H4 receptor was discovered initially in a search of the GenBank databases as sequence fragments retrieved in a partially sequenced human genomic contig mapped to chromosome 18. These sequences were used to retrieve a partial cDNA clone and, in combination with genomic fragments, were used to determine the full-length open reading frame of 390 amino acids. Northern analysis revealed a 3.0-kb transcript in rat testis and intestine. Radioligand binding studies indicated that the H4 receptor has a unique pharmacology and binds [3H]histamine (K d = 44 nM) and [3H]pyrilamine (K d = 32 nM) and several psychoactive compounds (amitriptyline, chlorpromazine, cyproheptadine, mianserin) with moderate affinity (K i range of 33–750 nM). Additionally, histamine induced a rapid internalization of HA-tagged H4 receptors in transfected human embryonic kidney 293 cells

    Multiple Statistical Analysis Techniques Corroborate Intratumor Heterogeneity in Imaging Mass Spectrometry Datasets of Myxofibrosarcoma

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    MALDI mass spectrometry can generate profiles that contain hundreds of biomolecular ions directly from tissue. Spatially-correlated analysis, MALDI imaging MS, can simultaneously reveal how each of these biomolecular ions varies in clinical tissue samples. The use of statistical data analysis tools to identify regions containing correlated mass spectrometry profiles is referred to as imaging MS-based molecular histology because of its ability to annotate tissues solely on the basis of the imaging MS data. Several reports have indicated that imaging MS-based molecular histology may be able to complement established histological and histochemical techniques by distinguishing between pathologies with overlapping/identical morphologies and revealing biomolecular intratumor heterogeneity. A data analysis pipeline that identifies regions of imaging MS datasets with correlated mass spectrometry profiles could lead to the development of novel methods for improved diagnosis (differentiating subgroups within distinct histological groups) and annotating the spatio-chemical makeup of tumors. Here it is demonstrated that highlighting the regions within imaging MS datasets whose mass spectrometry profiles were found to be correlated by five independent multivariate methods provides a consistently accurate summary of the spatio-chemical heterogeneity. The corroboration provided by using multiple multivariate methods, efficiently applied in an automated routine, provides assurance that the identified regions are indeed characterized by distinct mass spectrometry profiles, a crucial requirement for its development as a complementary histological tool. When simultaneously applied to imaging MS datasets from multiple patient samples of intermediate-grade myxofibrosarcoma, a heterogeneous soft tissue sarcoma, nodules with mass spectrometry profiles found to be distinct by five different multivariate methods were detected within morphologically identical regions of all patient tissue samples. To aid the further development of imaging MS based molecular histology as a complementary histological tool the Matlab code of the agreement analysis, instructions and a reduced dataset are included as supporting information

    MALDI imaging mass spectrometry for direct tissue analysis: a new frontier for molecular histology

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    Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is a powerful tool for investigating the distribution of proteins and small molecules within biological systems through the in situ analysis of tissue sections. MALDI-IMS can determine the distribution of hundreds of unknown compounds in a single measurement and enables the acquisition of cellular expression profiles while maintaining the cellular and molecular integrity. In recent years, a great many advances in the practice of imaging mass spectrometry have taken place, making the technique more sensitive, robust, and ultimately useful. In this review, we focus on the current state of the art of MALDI-IMS, describe basic technological developments for MALDI-IMS of animal and human tissues, and discuss some recent applications in basic research and in clinical settings
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