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Sample records for attenuates egf-induced rapid

  1. Estradiol attenuates EGF-induced rapid uPAR mobilization and cell migration via the G-protein-coupled receptor 30 in ovarian cancer cells

    DEFF Research Database (Denmark)

    Henic, Emir; Noskova, Vera; Høyer-Hansen, Gunilla;

    2009-01-01

    mobilization of uPAR from detergent-resistant domains such as lipid rafts. Estradiol influenced neither the amount of uPAR mRNA nor the rate of uPAR degradation or solubilization. The nuclear ER antagonists ICI 182780 and tamoxifen, which are GPR30 agonists, as well as the specifically constructed GPR30...

  2. Suberoylanilide hydroxamic acid (SAHA) inhibits EGF-induced cell transformation via reduction of cyclin D1 mRNA stability

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingjie [State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Rd, Haidian District, Beijing 100191 (China); Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States); Ouyang, Weiming; Li, Jingxia; Zhang, Dongyun; Yu, Yonghui; Wang, York [Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States); Li, Xuejun, E-mail: xjli@bjmu.edu.cn [State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Rd, Haidian District, Beijing 100191 (China); Huang, Chuanshu, E-mail: chuanshu.huang@nyumc.org [Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States)

    2012-09-01

    Suberoylanilide hydroxamic acid (SAHA) inhibiting cancer cell growth has been associated with its downregulation of cyclin D1 protein expression at transcription level or translation level. Here, we have demonstrated that SAHA inhibited EGF-induced Cl41 cell transformation via the decrease of cyclin D1 mRNA stability and induction of G0/G1 growth arrest. We found that SAHA treatment resulted in the dramatic inhibition of EGF-induced cell transformation, cyclin D1 protein expression and induction of G0/G1 growth arrest. Further studies showed that SAHA downregulation of cyclin D1 was only observed with endogenous cyclin D1, but not with reconstitutionally expressed cyclin D1 in the same cells, excluding the possibility of SAHA regulating cyclin D1 at level of protein degradation. Moreover, SAHA inhibited EGF-induced cyclin d1 mRNA level, whereas it did not show any inhibitory effect on cyclin D1 promoter-driven luciferase reporter activity under the same experimental conditions, suggesting that SAHA may decrease cyclin D1 mRNA stability. This notion was supported by the results that treatment of cells with SAHA decreased the half-life of cyclin D1 mRNA from 6.95 h to 2.57 h. Consistent with downregulation of cyclin D1 mRNA stability, SAHA treatment also attenuated HuR expression, which has been well-characterized as a positive regulator of cyclin D1 mRNA stability. Thus, our study identifies a novel mechanism responsible for SAHA inhibiting cell transformation via decreasing cyclin D1 mRNA stability and induction of G0/G1 growth arrest in Cl41 cells. -- Highlights: ► SAHA inhibits cell transformation in Cl41 cells. ► SAHA suppresses Cyclin D1 protein expression. ► SAHA decreases cyclin D1 mRNA stability.

  3. PLC-gamma1 and Rac1 coregulate EGF-induced cytoskeleton remodeling and cell migration.

    Science.gov (United States)

    Li, Siwei; Wang, Qian; Wang, Yi; Chen, Xinmei; Wang, Zhixiang

    2009-06-01

    It is well established that epidermal growth factor (EGF) induces the cytoskeleton reorganization and cell migration through two major signaling cascades: phospholipase C-gamma1 (PLC-gamma1) and Rho GTPases. However, little is known about the cross talk between PLC-gamma1 and Rho GTPases. Here we showed that PLC-gamma1 forms a complex with Rac1 in response to EGF. This interaction is direct and mediated by PLC-gamma1 Src homology 3 (SH3) domain and Rac1 (106)PNTP(109) motif. This interaction is critical for EGF-induced Rac1 activation in vivo, and PLC-gamma1 SH3 domain is actually a potent and specific Rac1 guanine nucleotide exchange factor in vitro. We have also demonstrated that the interaction between PLC-gamma1 SH3 domain and Rac1 play a significant role in EGF-induced F-actin formation and cell migration. We conclude that PLC-gamma1 and Rac1 coregulate EGF-induced cell cytoskeleton remodeling and cell migration by a direct functional interaction.

  4. EBP50 inhibits EGF-induced breast cancer cell proliferation by blocking EGFR phosphorylation.

    Science.gov (United States)

    Yao, Wenfang; Feng, Duiping; Bian, Weihua; Yang, Longyan; Li, Yang; Yang, Zhiyu; Xiong, Ying; Zheng, Junfang; Zhai, Renyou; He, Junqi

    2012-11-01

    Ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50) suppresses breast cancer cell proliferation, potentially through its regulatory effect on epidermal growth factor receptor (EGFR) signaling, although the mechanism by which this occurs remains unknown. Thus in our studies, we aimed to determine the effect of EBP50 expression on EGF-induced cell proliferation and activation of EGFR signaling in the breast cancer cell lines, MDA-MB-231 and MCF-7. In MDA-MB-231 cells, which express low levels of EBP50, EBP50 overexpression inhibited EGF-induced cell proliferation, ERK1/2 and AKT phosphorylation. In MCF-7 cells, which express high levels of EBP50, EBP50 knockdown promoted EGF-induced cell proliferation, ERK1/2 and AKT phosphorylation. Knockdown of EBP50 in EBP50-overexpressed MDA-MB-231 cells abrogated the inhibitory effect of EBP50 on EGF-stimulated ERK1/2 phosphorylation and restoration of EBP50 expression in EBP50-knockdown MCF-7 cells rescued the inhibition of EBP50 on EGF-stimulated ERK1/2 phosphorylation, further confirming that the activation of EGF-induced downstream molecules could be specifically inhibited by EBP50 expression. Since EGFR signaling was triggered by EGF ligands via EGFR phosphorylation, we further detected the phosphorylation status of EGFR in the presence or absence of EBP50 expression. Overexpression of EBP50 in MDA-MB-231 cells inhibited EGF-stimulated EGFR phosphorylation, whereas knockdown of EBP50 in MCF-7 cells enhanced EGF-stimulated EGFR phosphorylation. Meanwhile, total expression levels of EGFR were unaffected during EGF stimulation. Taken together, our data shows that EBP50 can suppress EGF-induced proliferation of breast cancer cells by inhibiting EGFR phosphorylation and blocking EGFR downstream signaling in breast cancer cells. These results provide further insight into the molecular mechanism by which EBP50 regulates the development and progression of breast cancer.

  5. Regulation of EGF-induced ERK/MAPK Activation and EGFR Internalization by G Protein-coupled Receptor Kinase 2

    Institute of Scientific and Technical Information of China (English)

    Jingxia GAO; Jiali LI; Lan MA

    2005-01-01

    G protein-coupled receptor kinases (GRKs) mediate agonist-induced phosphorylation and desensitization of various G protein-coupled receptors (GPCRs). We investigate the role of GRK2 on epidermal growth factor (EGF) receptor signaling, including EGF-induced extracellular signal-regulated kinase and mitogen-activated protein kinase (ERK/MAPK) activation and EGFR internalization. Immunoprecipitation and immunofluorescence experiments show that EGF stimulates GRK2 binding to EGFR complex and GRK2 translocating from cytoplasm to the plasma membrane in human embryonic kidney 293 cells. Western blotting assay shows that EGF-induced ERK/MAPK phosphorylation increases 1.9-fold, 1.1-fold and 1.5-fold (P<0.05) at time point 30, 60 and 120 min, respectively when the cells were transfected with GRK2,suggesting the regulatory role of GRK2 on EGF-induced ERK/MAPK activation. Flow cytometry experiments show that GRK2 overexpression has no effect on EGF-induced EGFR internalization, however, it increases agonist-induced G protein-coupled δ opioid receptor internalization by approximately 40% (P<0.01). Overall,these data suggest that GRK2 has a regulatory role in EGF-induced ERK/MAPK activation, and that the mechanisms underlying the modulatory role of GRK2 in EGFR and GPCR signaling pathways are somewhat different at least in receptor internalization.

  6. Calcium regulation of EGF-induced ERK5 activation: role of Lad1-MEKK2 interaction.

    Directory of Open Access Journals (Sweden)

    Zhong Yao

    Full Text Available The ERK5 cascade is a MAPK pathway that transmits both mitogenic and stress signals, yet its mechanism of activation is not fully understood. Using intracellular calcium modifiers, we found that ERK5 activation by EGF is inhibited both by the depletion and elevation of intracellular calcium levels. This calcium effect was found to occur upstream of MEKK2, which is the MAP3K of the ERK5 cascade. Co-immunoprecipitation revealed that EGF increases MEKK2 binding to the adaptor protein Lad1, and this interaction was reduced by the intracellular calcium modifiers, indicating that a proper calcium concentration is required for the interactions and transmission of EGF signals to ERK5. In vitro binding assays revealed that the proper calcium concentration is required for a direct binding of MEKK2 to Lad1. The binding of these proteins is not affected by c-Src-mediated phosphorylation on Lad1, but slightly affects the Tyr phosphorylation of MEKK2, suggesting that the interaction with Lad1 is necessary for full Tyr phosphorylation of MEKK2. In addition, we found that changes in calcium levels affect the EGF-induced nuclear translocation of MEKK2 and thereby its effect on the nuclear ERK5 activity. Taken together, these findings suggest that calcium is required for EGF-induced ERK5 activation, and this effect is probably mediated by securing proper interaction of MEKK2 with the upstream adaptor protein Lad1.

  7. Oncogenic potential of CK2α and its regulatory role in EGF-induced HDAC2 expression in human liver cancer.

    Science.gov (United States)

    Kim, Hyung S; Chang, Young G; Bae, Hyun J; Eun, Jung W; Shen, Qingyu; Park, Se J; Shin, Woo C; Lee, Eun K; Park, Soha; Ahn, Young M; Park, Won S; Lee, Jung Y; Nam, Suk W

    2014-02-01

    Histone deacetylase 2 (HDAC2) is aberrantly regulated and plays a pivotal role in the development of hepatocellular carcinoma (HCC) through regulation of cell-cycle components at the transcriptional level, but the underlying mechanism leading to oncogenic HDAC2 remains unknown. In this study, we show that expression of CK2α (casein kinase II α subunit) was up-regulated in a large cohort of human HCC patients, and that high expression of CK2α was significantly associated with poor prognosis of HCC patients in terms of five-year overall survival. It was also found that CK2α over-expression positively correlated with HDAC2 over-expression in a subset of HCCs. We observed that treatment with epidermal growth factor (EGF) elicited an increase in CK2α expression and Akt phosphorylation, causing induction of HDAC2 expression in liver cancer cells. It was also observed that ectopic expression of dominant-negative CK2α blocked EGF-induced HDAC2 expression, and that ectopic CK2α expression attenuated the suppressive effect of Akt knockdown on HDAC2 expression in liver cancer cells. Targeted disruption of CK2α influenced the cell cycle, causing a significant increase in the number of liver cancer cells remaining in G₂/M phase, and suppressed growth via repression of Cdc25c and cyclin B in liver cancer cells. Taken together, our findings suggest the oncogenic potential of CK2α in liver tumorigenesis. Furthermore, a regulatory mechanism for HDAC2 expression is proposed whereby EGF induces transcriptional activation of HDAC2 by CK2α/Akt activation in liver cancer cells. Therefore, this makes CK2α a promising target in cancer therapy.

  8. The Characteristics Variation of Hepatic Progenitors after TGF-β1-Induced Transition and EGF-Induced Reversion.

    Science.gov (United States)

    Wang, Ping; Cong, Min; Liu, Tianhui; Yang, Aiting; Sun, Guangyong; Zhang, Dong; Huang, Jian; Sun, Shujie; Mao, Jia; Ma, Hong; Jia, Jidong; You, Hong

    2016-01-01

    Profibrogenesis cytokine, transforming growth factor- (TGF-) β1, induces hepatic progenitors experiencing epithelial to mesenchymal transition (EMT) to matrix synthesis cells, even tumor initiating cells. Our previous data found that epidermal growth factor (EGF) blocks and reverses TGF-β1-induced transition. The aim of this study is to determine the characteristic changes of hepatic progenitors after TGF-β1-induced transition and EGF-induced reversion. Hepatic oval cells, rat hepatic progenitors, were isolated from rats fed a choline-deficient diet supplemented with ethionine. TGF-β1-containing medium was used for inducing EMT, while EGF-containing medium was used for reversing EMT. During TGF-β1-induced transition and EGF-induced reversion, hepatic oval cells sustained their progenitor cell marker expression, including α-fetoprotein, albumin, and cytokeratin-19. The proliferation ability and differentiation potential of these cells were suppressed by TGF-β1, while EGF resumed these capacities to the level similar to the control cells. RNA microarray analysis showed that most of the genes with significant changes after TGF-β1 incubation were recovered by EGF. Signal pathway analysis revealed that TGF-β1 impaired the pathways of cell cycle and cytochrome P450 detoxification, and EGF reverted TGF-β1 effects through activating MAPK and PI3K-Akt pathway. EGF reverses the characteristics impaired by TGF-β1 in hepatic oval cells, serving as a protective cytokine to hepatic progenitors. PMID:26955393

  9. Janus kinases and Src family kinases in the regulation of EGF-induced vimentin expression in MDA-MB-468 breast cancer cells.

    Science.gov (United States)

    Stewart, Teneale A; Azimi, Iman; Brooks, Andrew J; Thompson, Erik W; Roberts-Thomson, Sarah J; Monteith, Gregory R

    2016-07-01

    Epithelial-mesenchymal transition (EMT) is an important process associated with the metastasis of breast cancer cells. Members of the Janus kinases (JAKs) and Src family kinases (SFKs) are implicated in the regulation of an invasive phenotype in various cancer cell types. Using the pharmacological inhibitors JAK Inhibitor I (a pan-JAK inhibitor) and PP2 we investigated the role of the JAKs and SFKs, respectively, in the regulation of EMT markers in the MDA-MB-468 breast cancer cell line model of epidermal growth factor (EGF)-induced EMT. We identified selective inhibition of EGF induction of the mesenchymal marker vimentin by PP2 and JAK Inhibitor I. The effect of JAK Inhibitor I on vimentin protein induction occurred at a concentration lower than that required to significantly inhibit EGF-mediated signal transducer and activator of transcription 3 (STAT3)-phosphorylation, suggesting involvement of a STAT3-independent mechanism of EGF-induced vimentin regulation by JAKs. Despite our identification of a role for the JAK family in EGF-induced vimentin protein expression, siRNA-mediated silencing of each member of the JAK family was unable to phenocopy pharmacological inhibition, indicating potential redundancy among the JAK family members in this pathway. While SFKs and JAKs do not represent global regulators of the EMT phenotype, our findings have identified a role for members of these signaling pathways in the regulation of EGF-induced vimentin expression in the MDA-MB-468 breast cancer cell line. PMID:27163529

  10. Rapid tolerance against focal cerebral ischemia induced by isoflurane anesthesia is attenuated by adenosine A1 receptor antagonist in rats

    Institute of Scientific and Technical Information of China (English)

    刘艳红; 熊利泽

    2003-01-01

    The brief anesthesia with isoflurane induces rapid tolerance against focal cerebral ischemia in rats and adenosine A1 receptor antagonist, DPCPX, attenuates the beneficial effect of isoflurane preconditioning.

  11. EGF-induced expansion of migratory cells in the rostral migratory stream.

    Directory of Open Access Journals (Sweden)

    Olle R Lindberg

    Full Text Available The presence of neural stem cells in the adult brain is currently widely accepted and efforts are made to harness the regenerative potential of these cells. The dentate gyrus of the hippocampal formation, and the subventricular zone (SVZ of the anterior lateral ventricles, are considered the main loci of adult neurogenesis. The rostral migratory stream (RMS is the structure funneling SVZ progenitor cells through the forebrain to their final destination in the olfactory bulb. Moreover, extensive proliferation occurs in the RMS. Some evidence suggest the presence of stem cells in the RMS, but these cells are few and possibly of limited differentiation potential. We have recently demonstrated the specific expression of the cytoskeleton linker protein radixin in neuroblasts in the RMS and in oligodendrocyte progenitors throughout the brain. These cell populations are greatly altered after intracerebroventricular infusion of epidermal growth factor (EGF. In the current study we investigate the effect of EGF infusion on the rat RMS. We describe a specific increase of radixin(+/Olig2(+ cells in the RMS. Negative for NG2 and CNPase, these radixin(+/Olig2(+ cells are distinct from typical oligodendrocyte progenitors. The expanded Olig2(+ population responds rapidly to EGF and proliferates after only 24 hours along the entire RMS, suggesting local activation by EGF throughout the RMS rather than migration from the SVZ. In addition, the radixin(+/Olig2(+ progenitors assemble in chains in vivo and migrate in chains in explant cultures, suggesting that they possess migratory properties within the RMS. In summary, these results provide insight into the adaptive capacity of the RMS and point to an additional stem cell source for future brain repair strategies.

  12. [Rapid quantitative analysis of hydrocarbon composition of furfural extract oils using attenuated total reflection infrared spectroscopy].

    Science.gov (United States)

    Li, Na; Yuan, Hong-Fu; Hu, Ai-Qin; Liu, Wei; Song, Chun-Feng; Li, Xiao-Yu; Song, Yi-Chang; He, Qi-Jun; Liu, Sha; Xu, Xiao-Xuan

    2014-07-01

    A set of rapid analysis system for hydrocarbon composition of heavy oils was designed using attenuated total reflection FTIR spectrometer and chemometrics to determine the hydrocarbon composition of furfural extract oils. Sixty two extract oil samples were collected and their saturates and aromatics content data were determined according to the standard NB/SH/T0509-2010, then the total contents of resins plus asphaltenes were calculated by the subtraction method in the percentage of weight. Based on the partial least squares (PLS), calibration models for saturates, aromatics, and resin+asphaltene contents were established using attenuated total reflection FTIR spectroscopy, with their SEC, 1.43%, 0.91% and 1.61%, SEP, 1.56%, 1.24% and 1.81%, respectively, meeting the accuracy and repeatability required for the standard. Compared to the present standard method, the efficiency of hydrocarbon composition analysis for furfural extract oils is significantly improved by the new method which is rapid and simple. The system could also be used for other heavy oil analysis, with excellent extension and application foreground.

  13. Rapid hybrid encoding for high-resolution whole-brain fluid-attenuated imaging.

    Science.gov (United States)

    Lee, Hoonjae; Sohn, Chul-Ho; Park, Jaeseok

    2013-12-01

    Single-slab three-dimensional (3D) turbo spin-echo (TSE) imaging combined with inversion recovery (IR), which employs short, spatially non-selective refocusing pulses and signal prescription based variable refocusing flip angles (VFA) to increase imaging efficiency, was recently introduced to produce fluid-attenuated brain images for lesion detection. Despite the advantages, the imaging efficiency in this approach still remains limited because a substantially long time of inversion is needed to selectively suppress the signal intensity of cerebrospinal fluid (CSF) while fully recovering that of brain tissues. The purpose of this work is to develop a novel, rapid hybrid encoding method for highly efficient whole-brain fluid-attenuated imaging. In each time of repetition, volumetric data are continuously encoded using the hybrid modular acquisition in a sequential fashion even during IR signal transition, wherein reversed fast imaging with steady-state free precession (PSIF) is employed to encode intermediate-to-high spatial frequency signals prior to CSF nulling, while VFA-TSE is used to collect low-to-intermediate spatial frequency signals afterwards. Gradient-induced spin de-phasing between a pair of neighboring radio-frequency (RF) pulses in both PSIF and TSE modules is kept identical to avoid the occurrence of multiple echoes in a single acquisition window. Additionally, a two-step, alternate RF phase-cycling scheme is employed in the low spatial frequency region to eliminate free induction decay induced edge artifacts. Numerical simulations of the Bloch equations were performed to evaluate signal evolution of brain tissues along the echo train while optimizing imaging parameters. In vivo studies demonstrate that the proposed technique produces high-resolution isotropic fluid-attenuated whole-brain images in a clinically acceptable imaging time with substantially high signal-to-noise ratio for white matter while retaining lesion conspicuity.

  14. Rapid strategy for screening by pyrosequencing of influenza virus reassortants--candidates for live attenuated vaccines.

    Directory of Open Access Journals (Sweden)

    Svetlana V Shcherbik

    Full Text Available BACKGROUND: Live attenuated influenza vaccine viruses (LAIVs can be generated by classical reassortment of gene segments between a cold adapted, temperature sensitive and attenuated Master Donor Virus (MDV and a seasonal wild-type (wt virus. The vaccine candidates contain hemagglutinin (HA and neuraminidase (NA genes derived from the circulating wt viruses and the remaining six genes derived from the MDV strains. Rapid, efficient selection of the viruses with 6∶2 genome compositions from the large number of genetically different viruses generated during reassortment is essential for the biannual production schedule of vaccine viruses. METHODOLOGY/PRINCIPAL FINDINGS: This manuscript describes a new approach for the genotypic analysis of LAIV reassortant virus clones based on pyrosequencing. LAIV candidate viruses were created by classical reassortment of seasonal influenza A (H3N2 (A/Victoria/361/2011, A/Ohio/02/2012, A/Texas/50/2012 or influenza A (H7N9 (A/Anhui/1/2013 wt viruses with the MDV A/Leningrad/134/17/57(H2N2. Using strain-specific pyrosequencing assays, mixed gene variations were detected in the allantoic progenies during the cloning procedure. The pyrosequencing analysis also allowed for estimation of the relative abundance of segment variants in mixed populations. This semi-quantitative approach was used for selecting specific clones for the subsequent cloning procedures. CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that pyrosequencing analysis is a useful technique for rapid and reliable genotyping of reassortants and intermediate clones during the preparation of LAIV candidates, and can expedite the selection of vaccine virus candidates.

  15. Grape seed extract inhibits EGF-induced and constitutively active mitogenic signaling but activates JNK in human prostate carcinoma DU145 cells: possible role in antiproliferation and apoptosis.

    Science.gov (United States)

    Tyagi, Alpana; Agarwal, Rajesh; Agarwal, Chapla

    2003-03-01

    A loss of functional androgen receptor and an enhanced expression of growth factor receptors and associated ligands are causal genetic events in prostate cancer (PCA) progression. These genetic alterations lead to an epigenetic mechanism where a feedback autocrine loop between membrane receptor and ligand (e.g. EGFR-TGFalpha) results in a constitutive activation of MAPK-Elk1-AP1-mediated mitogenic signaling in human PCA at an advanced and androgen-independent stage. We rationalized that inhibiting these epigenetic events could be useful in controlling advanced PCA growth. Recently, we found that grape seed extract (GSE), a dietary supplement rich in flavonoid procyanidins, inhibits advanced and androgen-independent human PCA DU145 cell growth in culture and nude mice. Here, we performed detailed mechanistic studies to define the effect of GSE on EGFR-Shc-MAPK-Elk1-AP1-mediated mitogenic signaling in DU145 cells. Pretreatment of serum-starved cells with GSE resulted in 70% to almost complete inhibition of EGF-induced EGFR activation and 50% to complete inhibition of Shc activation, which corroborated with a comparable decrease in EGF-induced Shc binding to EGFR. Conversely, EGF-induced ERK1/2 phosphorylation was inhibited only by lower doses of GSE; in fact, higher doses showed an increase. Additional studies showed that GSE alone causes a dose- and time-dependent increase in ERK1/2 phosphorylation in starved DU145 cells that is inhibited by an MEK1 inhibitor PD98059. Independent of this increase in ERK1/2 phosphorylation, GSE showed a strong inhibition of ERK1/2 kinase activity to Elk1 in both cellular and cell-free systems. GSE treatment of cells also inhibited both EGF-induced and constitutively active Elk1 phosphorylation and AP1 activation. GSE treatment also showed DNA synthesis inhibition in starved and EGF-stimulated cells as well as loss of cell viability and apoptotic death that was further increased by adding MEK1 inhibitor. Since GSE strongly induced

  16. Ascofuranone suppresses EGF-induced HIF-1α protein synthesis by inhibition of the Akt/mTOR/p70S6K pathway in MDA-MB-231 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yun-Jeong; Cho, Hyun-Ji [Research Institute of Biomedical Engineering and Department of Medicine, Catholic University of Daegu School of Medicine, Daegu 705-718 (Korea, Republic of); Magae, Junji [Magae Bioscience Institute, 49-4 Fujimidai, Tsukuba 300-1263 (Japan); Lee, In-Kyu [Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 700-721 (Korea, Republic of); Park, Keun-Gyu, E-mail: kpark@knu.ac.kr [Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 700-721 (Korea, Republic of); Chang, Young-Chae, E-mail: ycchang@cu.ac.kr [Research Institute of Biomedical Engineering and Department of Medicine, Catholic University of Daegu School of Medicine, Daegu 705-718 (Korea, Republic of)

    2013-12-15

    Hypoxia-inducible factor (HIF)-1 plays an important role in tumor progression, angiogenesis and metastasis. In this study, we investigated the potential molecular mechanisms underlying the anti-angiogenic effect of ascofuranone, an isoprenoid antibiotic from Ascochyta viciae, in epidermal growth factor (EGF)-1 responsive human breast cancer cells. Ascofuranone significantly and selectively suppressed EGF-induced HIF-1α protein accumulation, whereas it did not affect the expression of HIF-1β. Furthermore, ascofuranone inhibited the transcriptional activation of vascular endothelial growth factor (VEGF) by reducing protein HIF-1α. Mechanistically, we found that the inhibitory effects of ascofuranone on HIF-1α protein expression are associated with the inhibition of synthesis HIF-1α through an EGF-dependent mechanism. In addition, ascofuranone suppressed EGF-induced phosphorylation of Akt/mTOR/p70S6 kinase, but the phosphorylation of ERK/JNK/p38 kinase was not affected by ascofuranone. These results suggest that ascofuranone suppresses EGF-induced HIF-1α protein translation through the inhibition of Akt/mTOR/p70S6 kinase signaling pathways and plays a novel role in the anti-angiogenic action. - Highlights: • Inhibitory effect of ascofuranone on HIF-1α expression is EGF-specific regulation. • Ascofuranone decreases HIF-1α protein synthesis through Akt/mTOR pathways. • Ascofuranone suppresses EGF-induced VEGF production and tumor angiogenesis.

  17. EGF induces microRNAs that target suppressors of cell migration: miR-15b targets MTSS1 in breast cancer.

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    Kedmi, Merav; Ben-Chetrit, Nir; Körner, Cindy; Mancini, Maicol; Ben-Moshe, Noa Bossel; Lauriola, Mattia; Lavi, Sara; Biagioni, Francesca; Carvalho, Silvia; Cohen-Dvashi, Hadas; Schmitt, Fernando; Wiemann, Stefan; Blandino, Giovanni; Yarden, Yosef

    2015-03-17

    Growth factors promote tumor growth and metastasis. We found that epidermal growth factor (EGF) induced a set of 22 microRNAs (miRNAs) before promoting the migration of mammary cells. These miRNAs were more abundant in human breast tumors relative to the surrounding tissue, and their abundance varied among breast cancer subtypes. One of these miRNAs, miR-15b, targeted the 3' untranslated region of MTSS1 (metastasis suppressor protein 1). Although xenografts in which MTSS1 was knocked down grew more slowly in mice initially, longer-term growth was unaffected. Knocking down MTSS1 increased migration and Matrigel invasion of nontransformed mammary epithelial cells. Overexpressing MTSS1 in an invasive cell line decreased cell migration and invasiveness, decreased the formation of invadopodia and actin stress fibers, and increased the formation of cellular junctions. In tissues from breast cancer patients with the aggressive basal subtype, an inverse correlation occurred with the high expression of miRNA-15b and the low expression of MTSS1. Furthermore, low abundance of MTSS1 correlated with poor patient prognosis. Thus, growth factor-inducible miRNAs mediate mechanisms underlying the progression of cancer. PMID:25783158

  18. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence.

    Science.gov (United States)

    Flynn, Padrig B; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P; Elliott, Christopher T; Laverty, Garry; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2016-05-31

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30-60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa.

  19. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence.

    Science.gov (United States)

    Flynn, Padrig B; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P; Elliott, Christopher T; Laverty, Garry; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2016-01-01

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30-60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa. PMID:27242335

  20. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence

    Science.gov (United States)

    Flynn, Padrig B.; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P.; Elliott, Christopher T.; Laverty, Garry; Gorman, Sean P.; Graham, William G.; Gilmore, Brendan F.

    2016-01-01

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30–60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa. PMID:27242335

  1. Rapid Quantification of Methamphetamine: Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Chemometrics

    Science.gov (United States)

    Hughes, Juanita; Ayoko, Godwin; Collett, Simon; Golding, Gary

    2013-01-01

    In Australia and increasingly worldwide, methamphetamine is one of the most commonly seized drugs analysed by forensic chemists. The current well-established GC/MS methods used to identify and quantify methamphetamine are lengthy, expensive processes, but often rapid analysis is requested by undercover police leading to an interest in developing this new analytical technique. Ninety six illicit drug seizures containing methamphetamine (0.1%–78.6%) were analysed using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance attachment and Chemometrics. Two Partial Least Squares models were developed, one using the principal Infrared Spectroscopy peaks of methamphetamine and the other a Hierarchical Partial Least Squares model. Both of these models were refined to choose the variables that were most closely associated with the methamphetamine % vector. Both of the models were excellent, with the principal peaks in the Partial Least Squares model having Root Mean Square Error of Prediction 3.8, R2 0.9779 and lower limit of quantification 7% methamphetamine. The Hierarchical Partial Least Squares model had lower limit of quantification 0.3% methamphetamine, Root Mean Square Error of Prediction 5.2 and R2 0.9637. Such models offer rapid and effective methods for screening illicit drug samples to determine the percentage of methamphetamine they contain. PMID:23936058

  2. Rapid quantification of methamphetamine: using attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR and chemometrics.

    Directory of Open Access Journals (Sweden)

    Juanita Hughes

    Full Text Available In Australia and increasingly worldwide, methamphetamine is one of the most commonly seized drugs analysed by forensic chemists. The current well-established GC/MS methods used to identify and quantify methamphetamine are lengthy, expensive processes, but often rapid analysis is requested by undercover police leading to an interest in developing this new analytical technique. Ninety six illicit drug seizures containing methamphetamine (0.1%-78.6% were analysed using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance attachment and Chemometrics. Two Partial Least Squares models were developed, one using the principal Infrared Spectroscopy peaks of methamphetamine and the other a Hierarchical Partial Least Squares model. Both of these models were refined to choose the variables that were most closely associated with the methamphetamine % vector. Both of the models were excellent, with the principal peaks in the Partial Least Squares model having Root Mean Square Error of Prediction 3.8, R(2 0.9779 and lower limit of quantification 7% methamphetamine. The Hierarchical Partial Least Squares model had lower limit of quantification 0.3% methamphetamine, Root Mean Square Error of Prediction 5.2 and R(2 0.9637. Such models offer rapid and effective methods for screening illicit drug samples to determine the percentage of methamphetamine they contain.

  3. Comparison of the efficacy of dexmedetomidine with that of esmolol in attenuating laryngoscopic and intubation response after rapid sequence induction

    OpenAIRE

    Yallapragada, Srivishnu Vardhan; Vidadala, Krishna Santh; Vemuri, Nagendra Nath; Shaik, Mastan Saheb

    2014-01-01

    Context: Laryngoscopy and tracheal intubation produce sympathetic overdrive by catecholamine release resulting in hypertension and tachycardia. Various agents are being tried to combat the intubation response over years. Aims: This study is aimed at comparing dexmedetomidine which is a highly selective alpha-2 agonist with an ultra-short acting beta blocker, esmolol to see which among the two is better in attenuating the hemodynamic response to laryngoscopy and tracheal intubation. Settings a...

  4. Chronic escitalopram treatment attenuated the accelerated rapid eye movement sleep transitions after selective rapid eye movement sleep deprivation: a model-based analysis using Markov chains

    OpenAIRE

    Kostyalik, Diána; Vas, Szilvia; Kátai, Zita; Kitka, Tamás; Gyertyán, István; Bagdy, Gyorgy; Tóthfalusi, László

    2014-01-01

    Background Shortened rapid eye movement (REM) sleep latency and increased REM sleep amount are presumed biological markers of depression. These sleep alterations are also observable in several animal models of depression as well as during the rebound sleep after selective REM sleep deprivation (RD). Furthermore, REM sleep fragmentation is typically associated with stress procedures and anxiety. The selective serotonin reuptake inhibitor (SSRI) antidepressants reduce REM sleep time and increas...

  5. Use of Attenuated Total Reflectance Mid-Infrared Spectroscopy for Rapid Prediction of Amino Acids in Chinese Rice Wine.

    Science.gov (United States)

    Wu, Zhengzong; Xu, Enbo; Long, Jie; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

    2015-08-01

    The high content of amino acids of Chinese rice wine (CRW), especially essential amino acids makes it a food increasingly demanded by consumers. Rapid detection technique of amino acid content, which is an important quality and function index of CRW, is highly desirable for consumers, producers as well as administrative authorities. In this study, the potential of Fourier transform infrared spectroscopy (FT-IR) as a novel and rapid analytical technique to determine 17 free amino acids in CRW were investigated. Genetic algorithms (GA) and synergy interval partial least squares (SiPLS) were used to select the most efficient spectral variables to improve the prediction precision of the classic partial least squares (PLS) model constructed on the full-spectrum. The results demonstrated that compared with the PLS model using all wavelengths of FT-IR spectra, the prediction precision of model based on the spectral variables selected by GA and SiPLS was significantly improved, especially for arginine and proline. After systemic comparison and discussion, it was found that GA-SiPLS model achieved the best performance, with the correlation coefficient in calibration (R(2) (cal)) higher than 0.80 and the residual predictive deviation higher than 2.00 for all of the free amino acids analyzed in this study. The overall results confirmed that FT-IR combined with efficient variable selection algorithms is a method that may be useful to replace the traditional methods for routine analysis of free amino acids in CRW.

  6. A rapid immunization strategy with a live attenuated tetravalent dengue vaccine elicits protective neutralizing antibody responses in non-human primates

    Directory of Open Access Journals (Sweden)

    Yuping eAmbuel

    2014-06-01

    Full Text Available Dengue viruses (DENVs cause approximately 390 million cases of DENV infections annually and over 3 billion people worldwide are at risk of infection. No dengue vaccine is currently available nor is there an antiviral therapy for DENV infections. We have developed a tetravalent live-attenuated DENV vaccine (TDV that consists of a molecularly characterized attenuated DENV-2 strain (TDV-2 and three chimeric viruses containing the pre-membrane and envelope genes of DENV-1, -3 and -4 expressed in the context of the TDV-2 genome. To impact dengue vaccine delivery in endemic areas and immunize travelers, a simple and rapid immunization strategy (RIS is preferred. We investigated RIS consisting of two full vaccine doses being administered subcutaneously or intradermally on the initial vaccination visit (day 0 at two different anatomical locations with a needle-free disposable syringe jet injection (DSJI delivery devices (PharmaJet in non-human primates (NHP. This vaccination strategy resulted in efficient priming and induction of neutralizing antibody responses to all four DENV serotypes comparable to those elicited by the traditional prime and boost (two months later vaccination schedule. In addition, the vaccine induced CD4+ and CD8+ T cells producing IFN-γ, IL-2, and TNF-α, and targeting the DENV-2 NS1, NS3 and NS5 proteins. Moreover, vaccine-specific T cells were cross-reactive with the non-structural NS3 and NS5 proteins of DENV-4. When animals were challenged with DENV-2 they were protected with no detectable viremia, and exhibited sterilizing immunity (no increase of neutralizing titers post- challenge. RIS could decrease vaccination visits and provide quick immune response to all four DENV serotypes. This strategy could increase vaccination compliance and would be especially advantageous for travelers into endemic areas.

  7. The Role of Phosphatidylinositol-3-Kinase and AMP-Activated Kinase in the Rapid Estrogenic Attenuation of Cannabinoid-Induced Changes in Energy Homeostasis

    Directory of Open Access Journals (Sweden)

    Edward J. Wagner

    2011-04-01

    Full Text Available We sought to determine the involvement of phosphatidyl inositol 3-kinase (PI3K and AMP-activated protein kinase (AMPK in the estrogenic antagonism of the cannabinoid regulation of energy homeostasis. Food intake and body weight were evaluated in ovariectomized female guinea pigs treated s.c. with estradiol benzoate (EB or its sesame oil vehicle, or the CB1 receptor antagonist AM251 or its cremephor/ethanol/0.9% saline vehicle. AMPK catalytic subunit, PI3K p85α regulatory subunit and proopiomelanocortin (POMC gene expression was assessed via quantitative RT-PCR in microdissected hypothalamic tissue. Whole-cell patch clamp recordings were performed in hypothalamic slices. Both EB and AM251 decreased food intake and weight gain, and increased AMPKα1, AMPKα2 and PI3K p85α gene expression in the mediobasal hypothalamus. 17β-Estradiol rapidly and markedly attenuated the decreases in glutamatergic miniature excitatory postsynaptic current (mEPSC frequency caused by the cannabinoid receptor agonist WIN 55,212-2 in POMC neurons. This rapid estrogenic diminution of cannabinoid-induced decreases in mEPSC frequency was blocked by the estrogen receptor (ER antagonist ICI 182,780 and the PI3K inhibitor PI 828, the latter of which also prevented the AM251-induced increase in mEPSC frequency. In addition, the AMPK activator metformin reversed the EB-induced decreases in food intake and weight gain and restored the ability of WIN 55,212-2 to reduce mEPSC frequency. These data reveal that estrogens physiologically antagonize cannabinoid-induced changes in appetite and POMC neuronal activity by activating PI3K and inhibiting AMPK. As such, they provide insight into the neuroanatomical substrates and signal transduction mechanisms upon which these counter-regulatory factors converge in the control of energy homeostasis.

  8. Rapid evaluation and quantitative analysis of eugenol derivatives in essential oils and cosmetic formulations on human skin using attenuated total reflectance–infrared spectroscopy

    OpenAIRE

    Wang, Lai-Hao; Sung, Wei-Chien

    2011-01-01

    We studied the fragrances 4-allylbenzenes (eugenol, methyl eugenol, acetyl eugenol) as well as 4-propenylbenzenes (isoeugenol) in commercial essential oils using a fast and nondestructive attenuated total reflectance–infrared (ATR–IR) spectroscopy method. The method was based on ATR–IR utilizing partial least square regression. The calibrations were modeled in the characteristic region for eugenol (1430–1432 cm−1), isoeugenol (960–970 cm−1) and methyl eugenol (803–807 cm−1). The models were t...

  9. Rapid discrimination and characterization of vanilla bean extracts by attenuated total reflection infrared spectroscopy and selected ion flow tube mass spectrometry.

    Science.gov (United States)

    Sharp, Michael D; Kocaoglu-Vurma, Nurdan A; Langford, Vaughan; Rodriguez-Saona, Luis E; Harper, W James

    2012-03-01

    Vanilla beans have been shown to contain over 200 compounds, which can vary in concentration depending on the region where the beans are harvested. Several compounds including vanillin, p-hydroxybenzaldehyde, guaiacol, and anise alcohol have been found to be important for the aroma profile of vanilla. Our objective was to evaluate the performance of selected ion flow tube mass spectrometry (SIFT-MS) and Fourier-transform infrared (FTIR) spectroscopy for rapid discrimination and characterization of vanilla bean extracts. Vanilla extracts were obtained from different countries including Uganda, Indonesia, Papua New Guinea, Madagascar, and India. Multivariate data analysis (soft independent modeling of class analogy, SIMCA) was utilized to determine the clustering patterns between samples. Both methods provided differentiation between samples for all vanilla bean extracts. FTIR differentiated on the basis of functional groups, whereas the SIFT-MS method provided more specific information about the chemical basis of the differentiation. SIMCA's discriminating power showed that the most important compounds responsible for the differentiation between samples by SIFT-MS were vanillin, anise alcohol, 4-methylguaiacol, p-hydroxybenzaldehyde/trimethylpyrazine, p-cresol/anisole, guaiacol, isovaleric acid, and acetic acid. ATR-IR spectroscopy analysis showed that the classification of samples was related to major bands at 1523, 1573, 1516, 1292, 1774, 1670, 1608, and 1431 cm(-1) , associated with vanillin and vanillin derivatives.

  10. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo Beom Eom; Hokyung Kim; Jinchae Kim; Un-Chul Paek; Byeong Ha Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  11. Stormwater Attenuation by Green Roofs

    Science.gov (United States)

    Sims, A.; O'Carroll, D. M.; Robinson, C. E.; Smart, C. C.

    2014-12-01

    Innovative municipal stormwater management technologies are urgently required in urban centers. Inadequate stormwater management can lead to excessive flooding, channel erosion, decreased stream baseflows, and degraded water quality. A major source of urban stormwater is unused roof space. Green roofs can be used as a stormwater management tool to reduce roof generated stormwater and generally improve the quality of runoff. With recent legislation in some North American cities, including Toronto, requiring the installation of green roofs on large buildings, research on the effectiveness of green roofs for stormwater management is important. This study aims to assess the hydrologic response of an extensive sedum green roof in London, Ontario, with emphasis on the response to large precipitation events that stress municipal stormwater infrastructure. A green roof rapidly reaches field capacity during large storm events and can show significantly different behavior before and after field capacity. At field capacity a green roof has no capillary storage left for retention of stormwater, but may still be an effective tool to attenuate peak runoff rates by transport through the green roof substrate. The attenuation of green roofs after field capacity is linked to gravity storage, where gravity storage is the water that is temporarily stored and can drain freely over time after field capacity has been established. Stormwater attenuation of a modular experimental green roof is determined from water balance calculations at 1-minute intervals. Data is used to evaluate green roof attenuation and the impact of field capacity on peak flow rates and gravity storage. In addition, a numerical model is used to simulate event based stormwater attenuation. This model is based off of the Richards equation and supporting theory of multiphase flow through porous media.

  12. Variable laser attenuator

    Science.gov (United States)

    Foltyn, Stephen R.

    1988-01-01

    The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

  13. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  14. Planetary Ices Attenuation Properties

    Science.gov (United States)

    McCarthy, Christine; Castillo-Rogez, Julie C.

    In this chapter, we review the topic of energy dissipation in the context of icy satellites experiencing tidal forcing. We describe the physics of mechanical dissipation, also known as attenuation, in polycrystalline ice and discuss the history of laboratory methods used to measure and understand it. Because many factors - such as microstructure, composition and defect state - can influence rheological behavior, we review what is known about the mechanisms responsible for attenuation in ice and what can be inferred from the properties of rocks, metals and ceramics. Since attenuation measured in the laboratory must be carefully scaled to geologic time and to planetary conditions in order to provide realistic extrapolation, we discuss various mechanical models that have been used, with varying degrees of success, to describe attenuation as a function of forcing frequency and temperature. We review the literature in which these models have been used to describe dissipation in the moons of Jupiter and Saturn. Finally, we address gaps in our present knowledge of planetary ice attenuation and provide suggestions for future inquiry.

  15. Frequency Dependent Attenuation Revisited

    CERN Document Server

    Richard, Kowar; Xavier, Bonnefond

    2009-01-01

    The work is inspired by thermo-and photoacoustic imaging, where recent efforts are devoted to take into account attenuation and varying wave speed parameters. In this paper we study causal equations describing propagation of attenuated pressure waves. We review standard models like frequency power laws and and the thermo-viscous equation. The lack of causality of standard models in the parameter range relevant for photoacoustic imaging requires to derive novel equations. The main ingredients for deriving causal equations are the Kramers-Kronig relation and the mathematical concept of linear system theory. The theoretical results of this work are underpined by numerical experiments.

  16. Control algorithms for dynamic attenuators

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-15

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  17. WAVE ATTENUATION OVER MUD BED: A PSEUDO-PLASTIC MODEL

    Institute of Scientific and Technical Information of China (English)

    Zhang Qing-he; Onyx W.H. Wai; Joseph H. W. Lee

    2003-01-01

    A two-layer model, with the upper layer being the perfect fluid and the lower layer being the pseudo-plastic fluid describing water wave attenuation over mud bed, was established. A simplified method based on the principle of equivalent work was applied to solve the boundary value problems. The computational results of the model show that the two-layer perfect fluid model and the perfect-viscous fluid model are all special cases of the present model. The complex nonlinear properties of wave attenuation over mud bed, can be explained by the present model, e.g., the wave dissipation rate decreases with the wave height in certain cases, while the small wave propagates over mud bed with less energy dissipation and large wave attenuates rapidly in other cases. Other factors influencing the wave attenuation were also discussed.

  18. Natural Biological Attenuation of Benzene in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Benzene has been found in subsurface unsaturated soil and groundwater beneath a petro-chemical plant. Although the groundwater contained several mg/L of benzene in the area immediately beneath the source, benzene was not detected in monitoring wells approximately 800m down stream. All kinds of physical processes such as adsorption and advection/dispersion are considered to account for the observed attenuation. The results indicated that the attenuation was primarily due to natural biological processes occurring within the aquifer. The evidence for the natural bioremediation of benzene from the groundwater included: (1) analysis of groundwater chemistry, (2) laboratory studies demonstrating benzene biodegradation in aquifer samples, and (3) computer simulations examining benzene transport. Laboratory experiments indicated that for conditions similar to those in the plume, the aerobic degradation of benzene by the naturally occurring microorganisms in the polluted groundwater samples was quite rapid with a half-life time of from 5 to 15 days. In situ analyses indicated the level of dissolved oxygen in the groundwater was over 2mg/L. Thus, oxygen should not limit the biodegradation. In fact, the benzene was also shown to degrade under anaerobic conditions. The results from the modeling simulations indicate that biodegradation is the dominant process influencing attenuation of the benzene.

  19. Seismic attenuation in fractured media

    International Nuclear Information System (INIS)

    The prime objective of this paper is to quantitatively estimate seismic attenuation caused by fractures with different physical parameters. In seismic wave simulation, the fractured media are treated as the anisotropic media and fractures are represented by frequency-dependent elastic constants. Based on numerical experiments with three different parameters, namely viscosity, porosity and the Lamé parameters, this paper has the following observations. First, seismic attenuation is not affected by the viscosity within fractures, although it increases with the increase of porosity and decreases with the increase of the Lamé parameters within fractures. Among the latter two parameters, seismic attenuation is more sensitive to the Lamé parameters than to the porosity. Second, for the attenuation anisotropy, low frequencies have more anisotropic effect than high frequencies. For example, a 50 Hz wavefield has the strongest anisotropy effect if compared to 100 and 150 Hz wavefields. The attenuation anisotropy for low frequency (say 50 Hz) is more sensitive to the viscosity than the porosity and the Lamé parameters have the weakest effect among these three parameters. These observations suggest that low-frequency seismic attenuation, and especially the attenuation anisotropy in low frequency, would have great potential for fluid discrimination within fractured media. (paper)

  20. Estimation of Water Vapour Attenuation And Rain Attenuation

    Directory of Open Access Journals (Sweden)

    K.Kalyana Srinivas

    2015-04-01

    Full Text Available Attenuation due to and water vapour and rain can severely degrade the radio wave propagation at centimeter or millimeter wavelengths. It restricts the path length of radio communication systems and limits the use of higher frequencies for line-of-sight microwave links and satellite communications. The attenuation will pose a greater problem to communication as the frequency of occurrence of heavy rain increases.In a tropical region, like Malaysia, where excessive rainfall is a common phenomenon throughout the year, the knowledge of the rain attenuation at the frequency of operation is extremely required for the design of a reliable terrestrial and earth space communication link at a particular location.

  1. The attenuation and the attenuators: strategies and tactics

    Directory of Open Access Journals (Sweden)

    Antonio Briz

    2013-12-01

    Full Text Available This work is inscribed in a research project (ES.POR.ATENUAÇÃO that seeks to analyze and explain the attenuator activity in different regional varieties of Spanish and Portuguese, in order to perform, subsequently, different contrastive intralinguistic and interlinguistic studies. In this article, we explain some of the theoretical and methodological principles on which are based the qualitative and quantitative analysis. And especially, we will refer to the concept of attenuation (Briz 1995, 2002, 2003, 2005, 2007a, 2012.

  2. Multi-transmitting formula for attenuating waves

    Institute of Scientific and Technical Information of China (English)

    陈少林; 廖振鹏

    2003-01-01

    The MTF is extended to case of attenuating incident wave by introducing an attenuation coefficient. The reflection coefficients of this modified MTF and MTF areevaluated and compared when an attenuating wave impinges on the boundary, and the results demonstrate that MTF can be used to absorb slightly attenuating wavesand the modified MTF is more capable of absorbing heavily attenuating waves than MTF. The accuracy of modified MTF is also tested by numerical examples of fluid saturated porous media.

  3. Photoacoustic Imaging Taking into Account Attenuation

    CERN Document Server

    Kowar, Richard

    2010-01-01

    First, we review existing attenuation models and discuss their causality properties, which we believe to be essential for algorithms for inversion with attenuated data. Then, we survey causality properties of common attenuation models. We also derive integro-differential equations which the attenuated waves are satisfying. In addition we discuss the ill--conditionness of the inverse problem for calculating the unattenuated wave from the attenuated one.

  4. Sound attenuation in magnetorheological fluids

    Science.gov (United States)

    Rodríguez-López, J.; Elvira, L.; Resa, P.; Montero de Espinosa, F.

    2013-02-01

    In this work, the attenuation of ultrasonic elastic waves propagating through magnetorheological (MR) fluids is analysed as a function of the particle volume fraction and the magnetic field intensity. Non-commercial MR fluids made with iron ferromagnetic particles and two different solvents (an olive oil based solution and an Araldite-epoxy) were used. Particle volume fractions of up to 0.25 were analysed. It is shown that the attenuation of sound depends strongly on the solvent used and the volume fraction. The influence of a magnetic field up to 212 mT was studied and it was found that the sound attenuation increases with the magnetic intensity until saturation is reached. A hysteretic effect is evident once the magnetic field is removed.

  5. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.;

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc biased...... at different points in the current-voltage characteristic. Both numerical calculations based on the Tien-Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the ''open'' state. The performance of a fully...... integrated submillimeter receiver circuit which comprises a flux-flow oscillator (FFO) as local oscillator, a superconducting variable attenuator, and a microwave SIS detector with tuned-out capacitance is also reported....

  6. X-Ray Attenuation Cell

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D.; Toor, A.

    2000-03-03

    To minimize the pulse-to-pulse variation, the LCLS FEL must operate at saturation, i.e. 10 orders of magnitude brighter spectral brilliance than 3rd-generation light sources. At this intensity, ultra-high vacuums and windowless transport are required. Many of the experiments, however, will need to be conducted at a much lower intensity thereby requiring a reliable means to reduce the x-ray intensity by many orders of magnitude without increasing the pulse-to-pulse variation. In this report we consider a possible solution for controlled attenuation of the LCLS x-ray radiation. We suggest using for this purpose a windowless gas-filled cell with the differential pumping. Although this scheme is easily realizable in principle, it has to be demonstrated that the attenuator can be made short enough to be practical and that the gas loads delivered to the vacuum line of sight (LOS) are acceptable. We are not going to present a final, optimized design. Instead, we will provide a preliminary analysis showing that the whole concept is robust and is worth further study. The spatial structure of the LCLS x-ray pulse at the location of the attenuator is shown in Fig. 1. The central high-intensity component, due to the FEL, has a FWHM of {approx}100 {micro}m. A second component, due to the undulator's broad band spontaneous radiation is seen as a much lower intensity ''halo'' with a FWHM of 1 mm. We discuss two versions of the attenuation cell. The first is directed towards a controlled attenuation of the FEL up to the 4 orders of magnitude in the intensity, with the spontaneous radiation halo being eliminated by collimators. In the second version, the spontaneous radiation is not sacrificed but the FEL component (as well as the first harmonic of the spontaneous radiation) gets attenuated by a more modest factor up to 100. We will make all the estimates assuming that the gas used in the attenuator is Xenon and that the energy of the FEL is 8.25 keV. At

  7. Use of ultrasonic attenuation and backscatter measurement for determining the grain size of austenitic steel OX18H12T

    International Nuclear Information System (INIS)

    A nondestructive method is described for the rapid determination of the grain size of nuclear piping. The method is based upon ultrasonic attenuation measurement, the coefficient of attenuation serving as a characteristic measure. The backscatter method is used to determine grain size distribution over the entire cross section. (author)

  8. Compact plasmonic variable optical attenuator

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Pétur Gordon;

    2008-01-01

    We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization...

  9. Novel Vaccine against Venezuelan Equine Encephalitis Combines Advantages of DNA Immunization and a Live Attenuated Vaccine

    OpenAIRE

    Tretyakova, Irina; Lukashevich, Igor S; Glass, Pamela; Wang, Eryu; Weaver, Scott; Pushko, Peter

    2012-01-01

    DNA vaccines combine remarkable genetic and chemical stability with proven safety and efficacy in animal models, while remaining less immunogenic in humans. In contrast, live-attenuated vaccines have the advantage of inducing rapid, robust, long-term immunity after a single-dose vaccination. Here we describe novel iDNA vaccine technology that is based on an infectious DNA platform and combines advantages of DNA and live attenuated vaccines. We applied this technology for vaccination against i...

  10. Engineering attenuated virulence of a Theileria annulata-infected macrophage.

    Directory of Open Access Journals (Sweden)

    Nadia Echebli

    Full Text Available Live attenuated vaccines are used to combat tropical theileriosis in North Africa, the Middle East, India, and China. The attenuation process is empirical and occurs only after many months, sometimes years, of in vitro culture of virulent clinical isolates. During this extensive culturing, attenuated lines lose their vaccine potential. To circumvent this we engineered the rapid ablation of the host cell transcription factor c-Jun, and within only 3 weeks the line engineered for loss of c-Jun activation displayed in vitro correlates of attenuation such as loss of adhesion, reduced MMP9 gelatinase activity, and diminished capacity to traverse Matrigel. Specific ablation of a single infected host cell virulence trait (c-Jun induced a complete failure of Theileria annulata-transformed macrophages to disseminate, whereas virulent macrophages disseminated to the kidneys, spleen, and lungs of Rag2/γC mice. Thus, in this heterologous mouse model loss of c-Jun expression led to ablation of dissemination of T. annulata-infected and transformed macrophages. The generation of Theileria-infected macrophages genetically engineered for ablation of a specific host cell virulence trait now makes possible experimental vaccination of calves to address how loss of macrophage dissemination impacts the disease pathology of tropical theileriosis.

  11. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  12. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-01-01

    In Section 1 of this first report we will describe the work we are doing to collect and analyze rock physics data for the purpose of modeling seismic attenuation from other measurable quantities such as porosity, water saturation, clay content and net stress. This work and other empirical methods to be presented later, will form the basis for ''Q pseudo-well modeling'' that is a key part of this project. In Section 2 of this report, we will show the fundamentals of a new method to extract Q, dispersion, and attenuation from field seismic data. The method is called Gabor-Morlet time-frequency decomposition. This technique has a number of advantages including greater stability and better time resolution than spectral ratio methods.

  13. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  14. Mechanisms of geometrical seismic attenuation

    Directory of Open Access Journals (Sweden)

    Igor B. Morozov

    2011-07-01

    Full Text Available In several recent reports, we have explained the frequency dependence of the apparent seismic quality-factor (Q observed in many studies according to the effects of geometrical attenuation, which was defined as the zero-frequency limit of the temporal attenuation coefficient. In particular, geometrical attenuation was found to be positive for most waves traveling within the lithosphere. Here, we present three theoretical models that illustrate the origin of this geometrical attenuation, and we investigate the causes of its preferential positive values. In addition, we discuss the physical basis and limitations of both the conventional and new attenuation models. For waves in media with slowly varying properties, geometrical attenuation is caused by variations in the wavefront curvature, which can be both positive (for defocusing and negative (for focusing. In media with velocity/density contrasts, incoherent reflectivity leads to geometrical-attenuation coefficients which are proportional to the mean squared reflectivity and are always positive. For «coherent» reflectivity, the geometrical attenuation is approximately zero, and the attenuation process can be described according to the concept of «scattering Q». However, the true meaning of this parameter is in describing the mean reflectivity within the medium, and not that of the traditional resonator quality factor known in mechanics. The general conclusion from these models is that non-zero and often positive levels of geometrical attenuation are common in realistic, heterogeneous media, both observationally and theoretically. When transformed into the conventional Q-factor form, this positive geometrical attenuation leads to Q values that quickly increase with frequency. These predictions show that the positive frequency-dependent Q observed in many datasets might represent artifacts of the transformations of the attenuation coefficients into Q.

  1. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...... it into a frequency dependent part and frequency independent part. The latter results in an attenuation factor that is multiplied onto the responses from the individual elements, and the frequency dependent part is handled by attenuating the basic one-dimensional pulse. The influence on ultrasound fields from...

  2. Ultrasonic attenuation in cuprate superconductors

    Indian Academy of Sciences (India)

    T Gupta; D M Gaitonde

    2002-05-01

    We calculate the longitudinal ultrasonic attenuation rate (UAR) in clean d-wave superconductors in the Meissner and the mixed phases. In the Meissner phase we calculate the contribution of previously ignored processes involving the excitation of a pair of quasi-holes or quasi-particles. There is a contribution ∝ in the regime B ≪ F ≪ 0 and a contribution ∝ 1/ in the regime F ≪ B ≪ 0. We find that these contributions to the UAR are large and cannot be ignored. In the mixed phase, using a semi-classical description, we calculate the electronic quasi-particle contribution to the UAR which at very low , has a independent term proportional to $\\sqrt{H}$.

  3. Attenuation characteristics of gypsum wallboard

    International Nuclear Information System (INIS)

    Increased cost of lead is promoting enhanced usage of common building materials for shielding in diagnostic medical and dental facilities where only a few half-value layers (HVLs) are needed. Attenuation of primary beam X-ray photons in gypsum wallboard as a function of kVp, filtration, and wallboard thickness have been measured. Findings, obtained using a Victoreen 555 with an 0.1 DAS probe in poor geometry, are substantially in agreement with the sparse data in the literature but extend to thicker wall configurations and different kVp and filtration parameters. These findings are of value in maximizing the benefit/cost ratio for diagnostic shielding, and strengthen the conviction that, where used for shielding purposes, common building materials must be installed carefully and HVL-depth dependence considered thoroughly. (author)

  4. Lung attenuation measurements in healthy young adults.

    NARCIS (Netherlands)

    Smit, H.J.M.; Golding, R.P.; Schramel, F.M.N.H.; Devillé, W.L.; Manoliu, R.A.; Postmus, P.E.

    2003-01-01

    Background: High-resolution computed tomography (HRCT) attenuation measurements may be more sensitive in finding early emphysematous changes in relatively young subjects than lung function measurements. Objectives: To define lung attenuation parameters in smokers and never-smokers. Methods: A prospe

  5. Simple parameterization of nuclear attenuation data

    CERN Document Server

    Akopov, N; Akopov, Z

    2007-01-01

    Based on the nuclear attenuation data obtained by the HERMES experiment on nitrogen and krypton nuclei, it is shown that the nuclear attenuation $R_M^{h}$ can be parametrised in a form of a linear polynomial $P_1=a_{11}$ + $\\tau a_{12}$, where $\\tau$ is the formation time, which depends on the energy of the virtual photon $\

  6. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...

  7. Pyrvinium attenuates Hedgehog signaling downstream of smoothened.

    Science.gov (United States)

    Li, Bin; Fei, Dennis Liang; Flaveny, Colin A; Dahmane, Nadia; Baubet, Valérie; Wang, Zhiqiang; Bai, Feng; Pei, Xin-Hai; Rodriguez-Blanco, Jezabel; Hang, Brian; Orton, Darren; Han, Lu; Wang, Baolin; Capobianco, Anthony J; Lee, Ethan; Robbins, David J

    2014-09-01

    The Hedgehog (HH) signaling pathway represents an important class of emerging developmental signaling pathways that play critical roles in the genesis of a large number of human cancers. The pharmaceutical industry is currently focused on developing small molecules targeting Smoothened (Smo), a key signaling effector of the HH pathway that regulates the levels and activity of the Gli family of transcription factors. Although one of these compounds, vismodegib, is now FDA-approved for patients with advanced basal cell carcinoma, acquired mutations in Smo can result in rapid relapse. Furthermore, many cancers also exhibit a Smo-independent activation of Gli proteins, an observation that may underlie the limited efficacy of Smo inhibitors in clinical trials against other types of cancer. Thus, there remains a critical need for HH inhibitors with different mechanisms of action, particularly those that act downstream of Smo. Recently, we identified the FDA-approved anti-pinworm compound pyrvinium as a novel, potent (IC50, 10 nmol/L) casein kinase-1α (CK1α) agonist. We show here that pyrvinium is a potent inhibitor of HH signaling, which acts by reducing the stability of the Gli family of transcription factors. Consistent with CK1α agonists acting on these most distal components of the HH signaling pathway, pyrvinium is able to inhibit the activity of a clinically relevant, vismodegib -resistant Smo mutant, as well as the Gli activity resulting from loss of the negative regulator suppressor of fused. We go on to demonstrate the utility of this small molecule in vivo, against the HH-dependent cancer medulloblastoma, attenuating its growth and reducing the expression of HH biomarkers. PMID:24994715

  8. Live attenuated intranasal influenza vaccine.

    Science.gov (United States)

    Esposito, Susanna; Montinaro, Valentina; Groppali, Elena; Tenconi, Rossana; Semino, Margherita; Principi, Nicola

    2012-01-01

    Annual vaccination is the most effective means of preventing and controlling influenza epidemics, and the traditional trivalent inactivated vaccine (TIV) is by far the most widely used. Unfortunately, it has a number of limitations, the most important of which is its poor immunogenicity in younger children and the elderly, the populations at greatest risk of severe influenza. Live attenuated influenza vaccine (LAIV) has characteristics that can overcome some of these limitations. It does not have to be injected because it is administered intranasally. It is very effective in children and adolescents, among whom it prevents significantly more cases of influenza than the traditional TIV. However, its efficacy in adults has not been adequately documented, which is why it has not been licensed for use by adults by the European health authorities. LAIV is safe and well tolerated by children aged > 2 y and adults, but some concerns arisen regarding its safety in younger children and subjects with previous asthma or with recurrent wheezing. Further studies are needed to solve these problems and to evaluate the possible role of LAIV in the annual vaccination of the general population.

  9. Beta attenuation transmission system (BATS)

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm/sup 2/, of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A /sup 90/Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (..mu..P) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined.

  10. Attenuation of diacylglycerol second messengers

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, W.R.; Ganong, B.R.; Bell, R.M.

    1986-05-01

    Diacylglycerol(DAG) derived from phosphatidylinositol activates protein kinase C in agonist-stimulated cells. At least two pathways may contribute to the attenuation of the DAG signal: (1) phosphorylation to phosphatidic acid(PA) by DAG kinase(DGK), and (2) deacylation by DAG and monoacylglycerol lipases. A number of DAG analogs were tested as substrates and inhibitors of partially purified pig brain DGK. Two analogs were potent inhibitors in vitro, 1-monooleoylglycerol(MOG,K/sub I/ = 91 ..mu..M) and diotanoylethyleneglycol (diC/sub 8/EG, K/sub I/ = 58 ..mu..M). These compounds were tested in human platelets. DiC/sub 8/EG inhibited (70 - 100%) (/sup 32/P/sub i/) incorporation into PA in thrombin-stimulated platelets. Under these conditions the DAG signal was somewhat long-lived but was still metabolized, presumably by the lipase pathway. MOG treatment elevated DAG levels up to 4-fold in unstimulated platelets. The DAG formed was in a pool where it did not activate protein kinase C. Thrombin-stimulation of MOG-treated platelets resulted in DAG levels 10-fold higher than control platelets. This appears to be due to the inability of these platelets to metabolize agonist-linked DAG via the lipase pathway. The development of specific inhibitors of DAG kinase and DAG lipase, in conjunction with mass quantification of DAG levels as used here, will provide further insights into the regulation of DAG second messengers.

  11. Graphene-based Electronically Tuneable Microstrip Attenuator

    Directory of Open Access Journals (Sweden)

    L. Pierantoni

    2014-06-01

    Full Text Available This paper presents the design of a graphene- based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics can range from being a fairly good conductor to a highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the surface resistivity of graphene can be modified, thereby changing the insertion loss of the microstrip attenuator.

  12. Attenuation layer for magnetostatic wave (MSW) absorbers

    Science.gov (United States)

    Glass, H. L.; Adkins, L. R.; Stearns, F. S.

    1984-09-01

    A new technique has been developed for the suppression of MSW end reflections which give rise to passband ripple. The basic idea is to provide a thin film of highly attenuating epitaxial material at the ends of a MSW delay line while preserving high quality YIG in the active region of the device. The GGG wafer preparation is a three step process which involves: (1) the growth of the attenuation layer, (2) the removal of this layer from the central region of the wafer and (3) the growth of high quality YIG on the remaining structure. Delay lines using the attenuation layer for end terminations have been evaluated experimentally and compared to devices utilizing other termination methods. The results indicate that the attenuation layer method produces ripple suppression characteristics which are the equal of those obtained with other termination techniques. The advantage of this new method lies in its suitability for large quantity fabrication requirements.

  13. Radiation-attenuated vaccine for lungworm disease

    International Nuclear Information System (INIS)

    The work done at the Indian Veternary Research Institute, Izatnagar, on the development of a vaccine for lungworm diseases is reported. Research work done includes: (1) studies on the epidemiology and the incidence of the lungworm infections, (ii) studies on the radiation-attenuated lungworm Dictyocaulus filaria vaccine, (iii) studies on other parasites using ionizing radiation, (iv) incidence of lungworm infection in sheep in Jammu and Kashmir State, (v) suitable dose of gamma radiation for attenuation, (vi) laboratory studies with radiation-attenuated D. filaria vaccine, (vii) serology of D. filaria infection, (viii) field trials with the radiation-attenuated vaccine, (ix) immune response of previously exposed lambs to vaccination, (x) comparative susceptibility of sheep and goats to infection with D. filaria, (xi) quantitative studies of D. filaria in lambs and (xii) production and supply of lungworm vaccine. (A.K.)

  14. Electron Effective-Attenuation-Length Database

    Science.gov (United States)

    SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge)   This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).

  15. ATTENUATION AND FLANKING TRANSMISSION IN LIGHTWEIGHT STRUCTURES

    DEFF Research Database (Denmark)

    Brunskog, Jonas; Lhomond, Alice; Ohlrich, Mogens

    2007-01-01

    In this paper the attenuation and flanking transmissions of impact noise in lightweight building structures is studied using a modal approach. The structural field is mainly analysed, putting the main attention to the parts being important in the modelling. The amount of attenuation produced by the...... periodically reinforcing beams used in lightweight building structures is analysed. The consequence of these factors in modelling flanking transmission is also discussed....

  16. Attenuation analysis of long-haul NLOS atmospheric optical scattering communication

    Science.gov (United States)

    Zhang, Shihua; Wang, Jingyuan; Xu, Zhiyong; Song, Chao; Wang, Rong; Chen, Yiwang; Zhao, Jiyong; Wei, Yimei

    2016-06-01

    The attenuation characteristics of ultraviolet (UV) and infrared transmitting in the atmosphere is analyzed, when long-haul Non-Line-of-Sight (NLOS) optical scattering communication is considered. The effects of Rayleigh and Mie scattering to link performance are presented. Under given geometric configurations, a critical range RC is found. When communication range is shorter than RC, the attenuation of UV is lower than that of infrared. But the path loss of UV increases rapidly, while the path loss of infrared increases much slower. When communication range is longer than RC, the attenuation of UV is higher than that of infrared. Numerical values of RC under different geometries are analyzed. It is also indicated that, under arbitrary geometric configurations, the impact of the Rayleigh scattering to infrared scattering communication is weak, but to UV scattering, the Rayleigh scattering effect cannot be ignored.

  17. Rapid Prototyping Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC Rapid Prototyping (RP) Laboratory was established in December 1992 to provide low cost RP capabilities to the ARDEC engineering community. The Stratasys,...

  18. Maximum likelihood estimation of the attenuated ultrasound pulse

    DEFF Research Database (Denmark)

    Rasmussen, Klaus Bolding

    1994-01-01

    The attenuated ultrasound pulse is divided into two parts: a stationary basic pulse and a nonstationary attenuation pulse. A standard ARMA model is used for the basic pulse, and a nonstandard ARMA model is derived for the attenuation pulse. The maximum likelihood estimator of the attenuated ultra...

  19. Seismic attenuation studies at the Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Five high explosive shots ranging in size from 1,005-16,005 lbs (M/sub L/ of -0.1 to 2.0) were detonated at the Idaho National Engineering Laboratory (INEL) between May 15 and October 17, 1974. These detonations were part of INEL's program, conducted by the United States Geological Survey, to determine the seismic attenuation characteristics in the vicinity of the laboratory. Particle velocity time histories generated by the 5 shots were recorded by L-7 systems deployed at 22 of the 23 temporary locations having a distance range of 0.42-62.9 km from the energy source. In addition, a magnitude (m/sub b/) 6.1 teleseism in the Kuril Islands was recorded at 7 locations. Two important results which have a bearing on the features of the design earthquake response spectra for INEL were obtained: (1) the experimental data suggest that peak particle velocity (and probably acceleration) attenuates more rapidly (i.e., as R-2.18 in the vicinity of INEL than in other geographic areas of the United States and (2) the seismic response of sites off-Snake River Plain is significantly greater over a wide range of frequencies than the response of sites on-Snake River Plain. Additional experimental data are needed to improve the precision of these preliminary results

  20. Evolutionary characteristics of morbilliviruses during serial passages in vitro: Gradual attenuation of virus virulence.

    Science.gov (United States)

    Liu, Fuxiao; Wu, Xiaodong; Li, Lin; Zou, Yanli; Liu, Shan; Wang, Zhiliang

    2016-08-01

    The genus Morbillivirus is classified into the family Paramyxoviridae, and is composed of 6 members, namely measles virus (MV), rinderpest virus (RPV), peste-des-petits-ruminants virus (PPRV), canine distemper virus (CDV), phocine distemper virus (PDV) and cetacean morbillivirus (CeMV). The MV, RPV, PPRV and CDV have been successfully attenuated through their serial passages in vitro for the production of live vaccines. It has been demonstrated that the morbilliviral virulence in animals was progressively attenuated with their consecutive passages in vitro. However, only a few reports were involved in explanation of an attenuation-related mechanism on them until many years after the establishment of a quasispecies theory. RNA virus quasispecies arise from rapid evolution of viruses with high mutation rate during genomic replication, and play an important role in gradual loss of viral virulence by serial passages. Here, we overviewed the development of live-attenuated vaccine strains against morbilliviruses by consecutive passages in vitro, and further discussed a related mechanism concerning the relationship between virulence attenuation and viral evolution. PMID:27477502

  1. Comparison of non-attenuation corrected and attenuation corrected myocardial perfusion SPE

    Directory of Open Access Journals (Sweden)

    Hasan Raza

    2016-09-01

    Conclusion: This study demonstrates that CT based attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging significantly improved the specificity of the RCA territory compared with non-attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging in both genders irrespective of BMI.

  2. Cine CT for Attenuation Correction in Cardiac PET/CT

    OpenAIRE

    Alessio, Adam M.; Kohlmyer, Steve; Branch, Kelley; Chen, Grace; Caldwell, James; Kinahan, Paul

    2007-01-01

    In dual-modality PET/CT systems, the CT scan provides the attenuation map for PET attenuation correction. The current clinical practice of obtaining a single helical CT scan provides only a snapshot of the respiratory cycle, whereas PET occurs over multiple respiratory cycles. Misalignment of the attenuation map and emission image because of respiratory motion causes errors in the attenuation correction factors and artifacts in the attenuation-corrected PET image. To rectify this problem, we ...

  3. Rapid Tooling via Stereolithography

    OpenAIRE

    Montgomery, Eva

    2006-01-01

    Approximately three years ago, composite stereolithography (SL) resins were introduced to the marketplace, offering performance features beyond what traditional SL resins could offer. In particular, the high heat deflection temperatures and high stiffness of these highly filled resins have opened the door to several new rapid prototyping (RP) applications, including wind tunnel test modelling and, more recently, rapid tooling.

  4. Study on laser and infrared attenuation performance of carbon nanotubes

    Science.gov (United States)

    Liu, Xiang-cui; Liu, Qing-hai; Dai, Meng-yan; Cheng, Xiang; Fang, Guo-feng; Zhang, Tong; Liu, Haifeng

    2014-11-01

    In recent years, the weapon systems of laser and infrared (IR) imaging guidance have been widely used in modern warfare because of their high precision and strong anti-interference. However, military smoke, a rapid and effective passive jamming method, can effectively counteract the attack of precision-guided weapons by their scattering and absorbing effects. The traditional smoke has good visible light (0.4-0.76μm) obscurant performance, but hardly any effects to other electromagnetic wave bands while the weapon systems of laser and IR imaging guidance usually work in broad band, including the near-infrared (1-3μm), middle-infrared (3-5μm), far-infrared (8-14μm), and so on. Accordingly, exploiting new effective obscurant materials has attracted tremendous interest worldwide nowadays. As is known, the nano-structured materials have lots of unique properties comparing with the traditional materials suggesting that they might be the perfect alternatives to solve the problems above. Carbon nanotubes (CNTs) are well-ordered, all-carbon hollow graphitic nano-structured materials with a high aspect ratio, lengths from several hundred nanometers to several millimeters. CNTs possess many unique intrinsic physical-chemical properties and are investigated in many areas reported by the previous studies. However, no application research about CNTs in smoke technology field is reported yet. In this paper, the attenuation performances of CNTs smoke to laser and IR were assessed in 20m3 smoke chamber. The testing wavebands employed in experiments are 1.06μm and 10.6μm laser, 3-5μm and 8-14μm IR radiation. The main parameters were obtained included the attenuation rate, transmission rate, mass extinction coefficient, etc. The experimental results suggest that CNTs smoke exhibits excellent attenuation ability to the broadband IR radiation. Their mass extinction coefficients are all above 1m2·g-1. Nevertheless, the mass extinction coefficients vary with the sampling time

  5. Attenuation of ear muffs in Canadian mines

    Energy Technology Data Exchange (ETDEWEB)

    Savich, M.U.

    1979-12-01

    The main characteristics of eleven commercially available ear muffs were investigated in the laboratory and analyzed by a psychophysical and a physical method. Nine ear muffs were tested in mines. The three best muffs had bands passing behind the head. The ear muff with a support strap, which improves comfort and maintains a good fit during wear, showed the best attenuation. Causes of poor attenuation are listed. None of the ear muffs tested had all the characteristics desirable in an ideal unit. Because of unsatisfactory attenuation in working conditions, it should be a mandatory requirement that workers wear both ear muffs and ear plugs if the noise level is higher than 105 dBA.

  6. Research on Nanosecond Pulse Corona Discharge Attenuation

    International Nuclear Information System (INIS)

    A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control. Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted. The results show that the wave front decreases sharply during the corona discharge along the corona wire. The higher the amplitude of the applied pulse is, the more the amplitude of the wave front decreased. The wave attenuation responds in a lower corona discharge inversely. To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design

  7. Finite Element Analysis of Honeycomb Impact Attenuator

    Science.gov (United States)

    Yang, Seung-Yong; Choi, Seung-Kyu; Kim, Nohyu

    To participate in Student Formula Society of Automotive Engineers (SAE) competitions, it is necessary to build an impact attenuator that would give an average deceleration not to exceed 20g when it runs into a rigid wall. Students can use numerical simulations or experimental test data to show that their car satisfies this safety requirement. A student group to study formula cars at the Korea University of Technology and Education has designed a vehicle to take part in a SAE competition, and a honeycomb structure was adopted as the impact attenuator. In this paper, finite element calculations were carried out to investigate the dynamic behavior of the honeycomb attenuator. Deceleration and deformation behaviors were studied. Effect of the yield strength was checked by comparing the numerical results. ABAQUS/Explicit finite element code was used.

  8. Live attenuated vaccines for invasive Salmonella infections.

    Science.gov (United States)

    Tennant, Sharon M; Levine, Myron M

    2015-06-19

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed Salmonella Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B (currently uncommon but may become dominant again), Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines.

  9. Research on Nanosecond Pulse Corona Discharge Attenuation

    Institute of Scientific and Technical Information of China (English)

    HE Zheng-hao; XU Huai-li; BAI Jing; YU Fu-sheng; HU Feng; LI Jin

    2007-01-01

    A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control.Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted.The results show that the wave front decreases sharply during the corona discharge along the corona wire.The higher the amplitude of the applied pulse is,the more the amplitude of the wave front decreased.The wave attenuation responds in a lower corona discharge inversely.To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design.

  10. Graphene-Based Waveguide Terahertz Wave Attenuator

    Science.gov (United States)

    Jian-rong, Hu; Jiu-sheng, Li; Guo-hua, Qiu

    2016-07-01

    We design an electrically controllable terahertz wave attenuator by using graphene. We show that terahertz wave can be confined and propagate on S-shaped graphene waveguide with little radiation losses, and the confined terahertz wave is further manipulated and controlled via external applied voltage bias. The simulated results show that, when chemical potential changes from 0.03 into 0.05 eV, the extinction ratio of the terahertz wave attenuator can be tuned from 1.28 to 39.42 dB. Besides the simplicity, this novel terahertz wave attenuator has advantages of small size (24 × 30 μm2), a low insertion loss, and good controllability. It has a potential application for forthcoming planar terahertz wave integrated circuit fields.

  11. Is there seismic attenuation in the mantle?

    Science.gov (United States)

    Ricard, Y.; Durand, S.; Montagner, J.-P.; Chambat, F.

    2014-02-01

    The small scale heterogeneity of the mantle is mostly due to the mixing of petrological heterogeneities by a smooth but chaotic convection and should consist in a laminated structure (marble cake) with a power spectrum S(k) varying as 1/k, where k is the wavenumber of the anomalies. This distribution of heterogeneities during convective stirring with negligible diffusion, called Batchelor regime is documented by fluid dynamic experiments and corresponds to what can be inferred from geochemistry and seismic tomography. This laminated structure imposes density, seismic velocity and potentially, anisotropic heterogeneities with similar 1/k spectra. A seismic wave of wavenumber k0 crossing such a medium is partly reflected by the heterogeneities and we show that the scattered energy is proportional to k0S(2k0). The reduction of energy for the propagating wave appears therefore equivalent to a quality factor 1/Q∝k0S(2k0). With the specific 1/k spectrum of the mantle, the resulting apparent attenuation should therefore be frequency independent. We show that the total contribution of 6-9% RMS density, velocity and anisotropy would explain the observed S and P attenuation of the mantle. Although these values are large, they are not unreasonable and we discuss how they depend on the range of frequencies over which the attenuation is explained. If such a level of heterogeneity were present, most of the attenuation of the Earth would be due to small scale scattering by laminations, not by intrinsic dissipation. Intrinsic dissipation must certainly exist but might correspond to a larger, yet unobserved Q. This provocative result would explain the very weak frequency dependence of the attenuation, and the fact that bulk attenuation seems negligible, two observations that have been difficult to explain for 50 years.

  12. Ultrasound transmission attenuation tomography using energy-scaled amplitude ratios

    Science.gov (United States)

    Chen, Ting; Shin, Junseob; Huang, Lianjie

    2016-04-01

    Ultrasound attenuation of breast tumors is related to their types and pathological states, and can be used to detect and characterize breast cancer. Particularly, ultrasound scattering attenuation can infer the margin properties of breast tumors. Ultrasound attenuation tomography quantitatively reconstructs the attenuation properties of the breast. Our synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays records both ultrasound reflection and transmission signals. We develop an ultrasound attenuation tomography method using ultrasound energy-scaled amplitude decays of ultrasound transmission signals and conduct ultrasound attenuation tomography using a known sound-speed model. We apply our ultrasound transmission attenuation tomography method to a breast phantom dataset, and compare the ultrasound attenuation tomography results with conventional beamforming ultrasound images obtained using reflection signals. We show that ultrasound transmission attenuation tomography complements beamforming images in identifying breast lesions.

  13. SAP Sector Develops Rapidly

    Institute of Scientific and Technical Information of China (English)

    Zheng Chengwang

    2007-01-01

    @@ Stable demand growth internationally Super absorbent polymers (SAP) feature high water absorption, high water retention, rapid water absorption, great expanding power,strong thickening, strong anchoring and excellent elasticity.

  14. Rapid Lead Screening Test

    Science.gov (United States)

    ... Medical Procedures In Vitro Diagnostics Lab Tests Rapid Lead Screening Test Share Tweet Linkedin Pin it More ... reducing the need for a follow-up visit. Lead Risk Links Centers for Disease Control and Prevention ( ...

  15. Switching Control for Adaptive Disturbance Attenuation

    NARCIS (Netherlands)

    Battistelli, Giorgio; Mari, Daniele; Selvi, Daniela; Tesi, Alberto; Tesi, Pietro

    2014-01-01

    The problem of adaptive disturbance attenuation is addressed in this paper using a switching control approach. A finite family of stabilizing controllers is pre-designed, with the assumption that, for any possible operating condition, at least one controller is able to achieve a prescribed level of

  16. Microwave attenuation with composite of copper microwires

    Energy Technology Data Exchange (ETDEWEB)

    Gorriti, A.G.; Marin, P. [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Cortina, D. [Micromag S.L., Las Rozas, Madrid 28230 (Spain); Hernando, A., E-mail: antonio.hernando@adif.e [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Micromag S.L., Las Rozas, Madrid 28230 (Spain)

    2010-05-15

    It is shown that copper microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula.

  17. Attenuation of PRRSV by chimera construction

    Science.gov (United States)

    Two genetically distinct infectious recombinant virus clones (pMLV, constructed from Ingelvac® PRRS MLV and pMN184, constructed from virulent strain MN184) were developed to study attenuation of contemporary PRRSV. Two reciprocal chimeric clones (pMLVORF1/MN184 and pMN184ORF1/MLV) were then constru...

  18. ULTRASONIC ATTENUATION IN MIXED STATE OF NIOBIUM

    OpenAIRE

    Dominec, J.; MÍŠek, K.

    1987-01-01

    We have investigated the attenuation of ultrasonic waves in the mixed state of niobium, where a remarkable dip appears near the lower critical field . The measurement has been performed on one sample for various orientations of the wave vector and of the principal crystallographic axes of the sample with respect to external magnetic field.

  19. Hadron attenuation at HERMES and JLab

    OpenAIRE

    Falter, T.; Cassing, W.; Gallmeister, K.; Mosel, U.

    2005-01-01

    We investigate the attenuation of hadrons in deep inelastic lepton-nucleus scattering in the kinematical regime of the HERMES and Jefferson Lab experiments. The calculation is carried out in the framework of a BUU transport model. Our results indicate a strong influence of (pre)hadronic final state interactions on the observed multiplicity ratios.

  20. Attenuation correction for small animal PET tomographs

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Patrick L [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States); Rannou, Fernando R [Departamento de Ingenieria Informatica, Universidad de Santiago de Chile (USACH), Av. Ecuador 3659, Santiago (Chile); Chatziioannou, Arion F [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States)

    2005-04-21

    Attenuation correction is one of the important corrections required for quantitative positron emission tomography (PET). This work will compare the quantitative accuracy of attenuation correction using a simple global scale factor with traditional transmission-based methods acquired either with a small animal PET or a small animal x-ray computed tomography (CT) scanner. Two phantoms (one mouse-sized and one rat-sized) and two animal subjects (one mouse and one rat) were scanned in CTI Concorde Microsystem's microPET (registered) Focus{sup TM} for emission and transmission data and in ImTek's MicroCAT{sup TM} II for transmission data. PET emission image values were calibrated against a scintillation well counter. Results indicate that the scale factor method of attenuation correction places the average measured activity concentration about the expected value, without correcting for the cupping artefact from attenuation. Noise analysis in the phantom studies with the PET-based method shows that noise in the transmission data increases the noise in the corrected emission data. The CT-based method was accurate and delivered low-noise images suitable for both PET data correction and PET tracer localization.

  1. Mercury accumulation and attenuation at a rapidly forming delta with a point source of mining waste

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Bryce E., E-mail: bjohnson@ce.berkeley.edu [Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Esser, Bradley K. [Chemical Sciences Division, 7000 East Avenue, Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Whyte, Dyan C.; Ganguli, Priya M.; Austin, Carrie M. [California Regional Water Quality Control Board, 1515 Clay St., Suite 1400, Oakland, CA 94612 (United States); Hunt, James R. [Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2009-09-01

    The Walker Creek intertidal delta of Tomales Bay, California is impacted by a former mercury mine within the watershed. Eleven short sediment cores (10 cm length) collected from the delta found monomethylmercury (MMHg) concentrations ranging from 0.3 to 11.4 ng/g (dry wt.), with lower concentrations occurring at the vegetated marsh and upstream channel locations. Algal mats common to the delta's sediment surface had MMHg concentrations ranging from 7.5 to 31.5 ng/g, and the top 1 cm of sediment directly under the mats had two times greater MMHg concentrations compared to adjacent locations without algal covering. Spatial trends in resident biota reflect enhanced MMHg uptake at the delta compared to other bay locations. Eighteen sediment cores, 1 to 2 m deep, collected from the 1.2 km{sup 2} delta provide an estimate of a total mercury (Hg) inventory of 2500 {+-} 500 kg. Sediment Hg concentrations ranged from pre-mining background conditions of approximately 0.1 {mu}g/g to a post-mining maximum of 5 {mu}g/g. Sediment accumulation rates were determined from three sediment cores using measured differences of {sup 137}Cs activity. We estimate a pre-mining Hg accumulation of less than 20 kg/yr, and a period of maximum Hg accumulation in the 1970s and 1980s with loading rates greater than 50 kg/yr, corresponding to the failure of a tailings dam at the mine site. At the time of sampling (2003) over 40 kg/yr of Hg was still accumulating at the delta, indicating limited recovery. We attribute observed spatial evolution of elevated Hg levels to ongoing inputs and sediment re-working, and estimate the inventory of the anthropogenic fraction of total Hg to be at least 1500 {+-} 300 kg. We suggest ongoing sediment inputs and methylation at the deltaic surface support enhanced mercury levels for resident biota and transfer to higher trophic levels throughout the Bay.

  2. Breath-hold CT attenuation correction for quantitative cardiac SPECT

    OpenAIRE

    Koshino, Kazuhiro; Fukushima, Kazuhito; Fukumoto, Masaji; Sasaki, Kazunari; Moriguchi, Tetsuaki; Hori, Yuki; Zeniya, Tsutomu; Nishimura, Yoshihiro; Kiso, Keisuke; Iida, Hidehiro

    2012-01-01

    Background Attenuation correction of a single photon emission computed tomography (SPECT) image is possible using computed tomography (CT)-based attenuation maps with hybrid SPECT/CT. CT attenuation maps acquired during breath holding can be misaligned with SPECT, generating artifacts in the reconstructed images. The purpose of this study was to investigate the effects of respiratory phase during breath-hold CT acquisition on attenuation correction of cardiac SPECT imaging. Methods A series o...

  3. Rapid small lot manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, R.W.

    1998-05-09

    The direct connection of information, captured in forms such as CAD databases, to the factory floor is enabling a revolution in manufacturing. Rapid response to very dynamic market conditions is becoming the norm rather than the exception. In order to provide economical rapid fabrication of small numbers of variable products, one must design with manufacturing constraints in mind. In addition, flexible manufacturing systems must be programmed automatically to reduce the time for product change over in the factory and eliminate human errors. Sensor based machine control is needed to adapt idealized, model based machine programs to uncontrolled variables such as the condition of raw materials and fabrication tolerances.

  4. Rapid microbiology - raising awareness.

    Science.gov (United States)

    Bailie, Jonathan

    2016-01-01

    A 'high-level overview' of some of the emerging rapid microbiology technologies designed to help healthcare engineering and infection control teams working in hospitals and other healthcare facilities more rapidly identify potentially hazardous levels of waterborne microorganisms in their water systems, enabling them to take prompt remedial action, and a look at the some of the 'pros and cons' of such testing techniques, was given by Nalco technical director, Howard Barnes, the vice-chair of the Legionella Control Association (LCA), at a recent LCA open day. HEJ editor, Jonathan Bailie, reports.

  5. Attenuated response to repeated daily ozone exposures in asthmatic subjects

    Energy Technology Data Exchange (ETDEWEB)

    Gong, H. Jr.; Linn, W.S. [Rancho Low Amigos Medical Center, Downey, CA (United States); McManus, M.S. [Univ. of California, Los Angeles, CA (United States)

    1997-01-01

    The development of attenuated response ({open_quotes}tolerance{close_quotes}) to daily ozone (O{sub 3}) exposures in the laboratory is well established in healthy adult volunteers. However, the capability of asthmatics to develop tolerance during multiday ozone exposures in unclear. We exposed 10 adult volunteers with mild asthma to 0.4 ppm O{sub 3} in filtered air for 3 h/d on 5 consecutive d. Two similar filtered-air exposures during the preceding week served as controls. Follow-up O{sub 3} exposures were performed 4 and 7 d after the most recent consecutive exposure. All exposures were performed in an environmental chamber at 31 {degrees}C and 35% relative humidity. The subjects performed moderate exercise (mean ventilation rate of 32 l/min) for 15 min of each half-hour. Responses were measured with spirometry and symptom evaluations before and after each exposure, and a bronchial reactivity test (methacholine challenge) was conducted after each exposure. All response measurements showed clinically and statistically significant day-to-day variation. Symptom and forced-expiratory-volume-in-1-s responses were similarly large on the 1st and 2nd O{sub 3} exposure days, after which they diminished progressively, approaching filtered air response levels by the 5th consecutive O{sub 3} day. This tolerance was partially lost 4 and 7 d later. Bronchial reactivity peaked after the first O{sub 3} exposure and remained somewhat elevated after all subsequent O{sub 3} exposures, relative to its control level following filtered-air exposures. Individual responses varied widely; more severe initial responses to O{sub 3} predicted less rapid attenuation. We concluded that asthmatics can develop tolerance to frequent high-level O{sub 3} exposures in much the same manner as normal subjects, although the process may be slower and less fully effective in asthmatics. 27 refs., 3 figs., 4 tabs.

  6. Study on energy attenuation of ultrasonic Guided waves going through girth welds

    Energy Technology Data Exchange (ETDEWEB)

    Li Yibo; Jin Shijiu; Sun Liying [Tianjin University (China); Sha Jile [Bohai Oil Industry and Trade Company (China)

    2005-07-01

    Ultrasonic guided wave can be used to inspect some parts of the pipe which is inaccessible to other conventional NDT methods, and rapid, long distance inspection can be achieved. Thus, it enjoys promising broad application in the field of pipe inspection. When ultrasonic guided wave is excited at one location, its propagating distance along the pipe is depended on energy attenuation of ultrasonic guided wave. During the process of long-range pipe engineering inspection, ultrasonic guided waves may go through many girth welds and elbows. Girth weld reflects much energy of guided waves, thus they attenuate a great deal after passing several girth welds. Furthermore, defect detection either in the elbow region or beyond it is usually difficult due to its geometry complexity and flexural mode conversion in pipe elbow region. In this paper, factors that may cause attenuation of ultrasonic guided waves (longitudinal wave and torsional wave) were studied and research was carried out on energy attenuation of guided waves when going through girth welds and elbow. In the end, comparison of the two guided waves on sensitivity and location precision of defects such as notch, burr and branch was given. (author)

  7. Novel chikungunya vaccine candidate with an IRES-based attenuation and host range alteration mechanism.

    Directory of Open Access Journals (Sweden)

    Kenneth Plante

    2011-07-01

    Full Text Available Chikungunya virus (CHIKV is a reemerging mosquito-borne pathogen that has recently caused devastating urban epidemics of severe and sometimes chronic arthralgia. As with most other mosquito-borne viral diseases, control relies on reducing mosquito populations and their contact with people, which has been ineffective in most locations. Therefore, vaccines remain the best strategy to prevent most vector-borne diseases. Ideally, vaccines for diseases of resource-limited countries should combine low cost and single dose efficacy, yet induce rapid and long-lived immunity with negligible risk of serious adverse reactions. To develop such a vaccine to protect against chikungunya fever, we employed a rational attenuation mechanism that also prevents the infection of mosquito vectors. The internal ribosome entry site (IRES from encephalomyocarditis virus replaced the subgenomic promoter in a cDNA CHIKV clone, thus altering the levels and host-specific mechanism of structural protein gene expression. Testing in both normal outbred and interferon response-defective mice indicated that the new vaccine candidate is highly attenuated, immunogenic and efficacious after a single dose. Furthermore, it is incapable of replicating in mosquito cells or infecting mosquitoes in vivo. This IRES-based attenuation platform technology may be useful for the predictable attenuation of any alphavirus.

  8. Intracoronary imaging using attenuation-compensated optical coherence tomography allows better visualisation of coronary artery diseases

    Energy Technology Data Exchange (ETDEWEB)

    Foin, Nicolas, E-mail: nicolas.foin@gmail.com [International Centre for Circulatory Health, Imperial College London, W2 1LA London (United Kingdom); Mari, Jean Martial [University College London, London (United Kingdom); Nijjer, Sukhjinder; Sen, Sayan; Petraco, Ricardo [International Centre for Circulatory Health, Imperial College London, W2 1LA London (United Kingdom); Ghione, Matteo; Di Mario, Carlo [Biomedical Research Unit, Royal Brompton Hospital, London (United Kingdom); Davies, Justin E. [International Centre for Circulatory Health, Imperial College London, W2 1LA London (United Kingdom); Girard, Michaël J.A. [Department of Bioengineering, National University of Singapore (Singapore); Singapore Eye Research Institute (Singapore)

    2013-05-15

    Purpose: To allow an accurate diagnosis of coronary artery diseases by enhancing optical coherence tomography (OCT) images of atheromatous plaques using a novel automated attenuation compensation technique. Background: One of the major drawbacks of coronary OCT imaging is the rapid attenuation of the OCT signal, limiting penetration in tissue to only few millimetres. Visualisation of deeper anatomy is however critical for accurate assessment of plaque burden in-vivo. Methods: A compensation algorithm, previously developed to correct for light attenuation in soft tissues and to enhance contrast in ophthalmic OCT images, was applied to intracoronary plaque imaging using spectral-domain OCT. Results: Application of the compensation algorithm significantly increased tissue contrast in the vessel wall and atherosclerotic plaque boundaries. Contrast enhancement allows a better differentiation of plaque morphology, which is particularly important for the identification of lipid rich fibro atheromatous plaques and to guide decision on treatment strategy. Conclusion: The analysis of arterial vessel structure clinically captured with OCT is improved when used in conjunction with automated attenuation compensation. This approach may improve the OCT-based interpretation of coronary plaque morphology in clinical practice.

  9. Frequency Dependence of Attenuation Constant of Dielectric Materials

    Directory of Open Access Journals (Sweden)

    A. S. Zadgaonkar

    1975-01-01

    Full Text Available Different dielectric materials have been studied for frequency dependence of attenuation constant. The sensitive cathode ray oscillograph method has been used to evaluate to the dielectric constant and loss factor, and from these attenuation constants have been calculated. The temperature remaining constant, a regular increase has been observed in attenuation constant, at higher frequencies of electro-magnetic propagating wave.

  10. Simple Scheme for Variable High Power Laser Beam Attenuation

    OpenAIRE

    Bialkowski, Stephen E.

    1987-01-01

    A venetian style infrared attenuator placed prior to a pinhole spatial filter results in variable high‐power laser attenuation. This attenuation scheme has a wide dynamic range, results in high‐quality Gaussian beams, does not introduce beam walk‐off error, and is independent of polarization.

  11. Attenuation of microwaves by poly-disperse small spheroid particles

    Science.gov (United States)

    Zhang, Peichang; Wang, Zhenhui

    1998-08-01

    Expressions for calculating the attenuation cross sections of poly-disperse, small spheroids, whose rotatory axes are in specific status, have been derived from a universal formula for calculating the attenuation cross section of a particle of arbitrary shape. Attenuation cross sections of liquid, ice, and spongy spheroidal droplets in different size and eccentricity at different wave lengths have been computed and analyzed.

  12. Highly immunogenic variant of attenuated vaccinia virus.

    Science.gov (United States)

    Yakubitskyi, S N; Kolosova, I V; Maksyutov, R A; Shchelkunov, S N

    2016-01-01

    The LIVPΔ6 strain of vaccinia virus (VACV) was created by genetic engineering on the basis of previously obtained attenuated 1421ABJCN strain by target deletion of the A35R gene encoding an inhibitor of antigen presentation by the major histocompatibility complex class II. 1421ABJCN is the LIVP strain of VACV with five inactivated virulence genes encoding hemagglutinin (A56R), γ-interferon-binding protein (B8R), thymidine kinase (J2R), complement-binding protein (C3L), and Bcl2-like inhibitor of apoptosis (N1L). The highly immunogenic LIVPΔ6 strain could be an efficient fourth-generation attenuated vaccine against smallpox and other orthopoxvirus infections. PMID:27025484

  13. Carcinoma cervix with fat attenuating skull metastases

    Institute of Scientific and Technical Information of China (English)

    Anuradha Kapali; Atmakuri Sateesh Kumar; Mukunda Malathi; S D Shamsundar

    2016-01-01

    Skeletal metastasis in carcinoma cervix occurs in about 0.8-23% of cases. These lesions are usually radiographically lytic. Very few cases of metastases to the skull have been identiifed, about 5 cases to the best of our knowledge. We present a case of adenosquamous cell carcinoma of cervix with fat attenuating skull metastases in a 38-year-old lady that is not reported till date. The lesion was lytic, expansile and with negative attenuation of -15 to -30 Hounsifeld units corresponding to fat.Metastases must be included in the differentials of scalp lesions. A history of recent onset of swelling and associated lytic areas in calvarium on contrast enhanced computed tomography with multiplicity can give a clue to metastatic nature of disease.

  14. Particle size characterization by ultrasonic attenuation spectra

    Institute of Scientific and Technical Information of China (English)

    Mingxu Su; Minghua Xue; Xiaoshu Cai; Zhitao Shang; Feng Xu

    2008-01-01

    This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coupled-phase model are formulated simultaneously, the relationship between particle size distribution and ultrasonic spectrum is established, and a convergence criterion for calculation is quantified. Demonsa'ation inversion by the optimum regularization factor method is carded out to yield typical numerical results for discussion. With the experimental set-up developed by the Institute of Particle and Two-Phase Flow Measurement (IPTFM) at the University of Shanghai for Science and Technology, sand sediment particle size is measured by attenuation spectrum and analyzed using the above inversion algorithm and theoretical models. To validate the proposed ultrasonic spectrum particle sizing method, results are compared with those obtained by microscopy.

  15. Attenuation of gamma radiation in concrete shields

    International Nuclear Information System (INIS)

    The attenuation characteristics of γ radiation in concrete layers considering their mechanical resistence and densities were determined. A 137Cs source was used in a 'good geometry' arrangement to eliminate the effects of the buildup factor. The ordinary and the heavy concrete were irradiated and for the latter it was used as additives iron ore and Fe2O3 pellets in various grain sizes. The detection system consisted of a 2' x 2' NaI (Tl) crystal coupled to a photomultiplier tube and the associated electronic equipment. FORTRAN programs were used for determining the absorption coefficients and the attenuation factors. These programs calculate photopeak areas eliminating all contributions due to Compton effect and background. (Author)

  16. Two-dimensional dynamic fluid bowtie attenuators.

    Science.gov (United States)

    Hermus, James R; Szczykutowicz, Timothy P

    2016-01-01

    Fluence field modulated (FFM) CT allows for improvements in image quality and dose reduction. To date, only one-dimensional modulators have been proposed, as the extension to two-dimensional (2-D) modulation is difficult with solid-metal attenuation-based fluence field modulated designs. This work proposes to use liquid and gas to attenuate the x-ray beam, as unlike solids, these materials can be arranged allowing for 2-D fluence modulation. The thickness of liquid and the pressure for a given path length of gas were determined that provided the same attenuation as 30 cm of soft tissue at 80, 100, 120, and 140 kV. Liquid iodine, zinc chloride, cerium chloride, erbium oxide, iron oxide, and gadolinium chloride were studied. Gaseous xenon, uranium hexafluoride, tungsten hexafluoride, and nickel tetracarbonyl were also studied. Additionally, we performed a proof-of-concept experiment using a 96 cell array in which the liquid thickness in each cell was adjusted manually. Liquid thickness varied as a function of kV and chemical composition, with erbium oxide allowing for the smallest thickness. For the gases, tungsten hexaflouride required the smallest pressure to compensate for 30 cm of soft tissue. The 96 cell iodine attenuator allowed for a reduction in both dynamic range to the detector and scatter-to-primary ratio. For both liquids and gases, when k-edges were located within the diagnostic energy range used for imaging, the mean beam energy exhibited the smallest change with compensation amount. The thickness of liquids and the gas pressure seem logistically implementable within the space constraints of C-arm-based cone beam CT (CBCT) and diagnostic CT systems. The gas pressures also seem logistically implementable within the space and tube loading constraints of CBCT and diagnostic CT systems. PMID:26835499

  17. Narrow terahertz attenuation signatures in Bacillus thuringiensis.

    Science.gov (United States)

    Zhang, Weidong; Brown, Elliott R; Viveros, Leamon; Burris, Kellie P; Stewart, C Neal

    2014-10-01

    Terahertz absorption signatures from culture-cultivated Bacillus thuringiensis were measured with a THz photomixing spectrometer operating from 400 to 1200 GHz. We observe two distinct signatures centered at ∼955 and 1015 GHz, and attribute them to the optically coupled particle vibrational resonance (surface phonon-polariton) of Bacillus spores. This demonstrates the potential of the THz attenuation signatures as "fingerprints" for label-free biomolecular detection. PMID:23821459

  18. The attenuation coefficients in CT: Didactic review

    International Nuclear Information System (INIS)

    The review article refers details about the derivation of the Attenuation coefficient of the CT-Number, the electron density and physical density, the effective atomic number, dual KV scanning, the performance of different scanners, furtheron the CT-numbers of intracranial structures, the attempts of characterization of tissue by CT, measurements of effective atomic number and electron density, distribution and probability of occurance of CT-numbers, and distribution of CT-numbers in space. (AJ)

  19. Bubbles attenuate elastic waves at seismic frequencies

    Science.gov (United States)

    Tisato, Nicola; Quintal, Beatriz; Chapman, Samuel; Podladchikov, Yury; Burg, Jean-Pierre

    2016-04-01

    The vertical migration of multiphase fluids in the crust can cause hazardous events such as eruptions, explosions, pollution and earthquakes. Although seismic tomography could potentially provide a detailed image of such fluid-saturated regions, the interpretation of the tomographic signals is often controversial and fails in providing a conclusive map of the subsurface saturation. Seismic tomography should be improved considering seismic wave attenuation (1/Q) and the dispersive elastic moduli which allow accounting for the energy lost by the propagating elastic wave. In particular, in saturated media a significant portion of the energy carried by the propagating wave is dissipated by the wave-induced-fluid-flow and the wave-induced-gas-exsolution-dissolution (WIGED) mechanisms. The WIGED mechanism describes how a propagating wave modifies the thermodynamic equillibrium between different fluid phases causing the exsolution and the dissolution of the gas in the liquid, which in turn causes a significant frequency dependent 1/Q and moduli dispersion. The WIGED theory was initially postulated for bubbly magmas but only recently was extended to bubbly water and experimentally demonstrated. Here we report these theory and laboratory experiments. Specifically, we present i) attenuation measurements performed by means of the Broad Band Attenuation Vessel on porous media saturated with water and different gases, and ii) numerical experiments validating the laboratory observations. Finally, we will extend the theory to fluids and to pressure-temperature conditions which are typical of phreatomagmatic and hydrocarbon domains and we will compare the propagation of seismic waves in bubble-free and bubble-bearing subsurface domains. With the present contribution we extend the knowledge about attenuation in rocks which are saturated with multiphase fluid demonstrating that the WIGED mechanism could be extremely important to image subsurface gas plumes.

  20. Phonic Attenuation due to Screen-Barriers

    OpenAIRE

    Vasile Bacria; Nicolae Herişanu

    2011-01-01

    The technique of noise decreasing admits two basic approaches: an active approach and a passive one. In the frame of passive method one can count the employment of screen-barriers. In this paper we present some considerations on sound attenuation due to screen-barriers emphasizing the elements which influence it. The elucidation of these elements is made by measurements. The obtained results can be applied in every other practical situation concerning the protection against ...

  1. Narrow terahertz attenuation signatures in Bacillus thuringiensis.

    Science.gov (United States)

    Zhang, Weidong; Brown, Elliott R; Viveros, Leamon; Burris, Kellie P; Stewart, C Neal

    2014-10-01

    Terahertz absorption signatures from culture-cultivated Bacillus thuringiensis were measured with a THz photomixing spectrometer operating from 400 to 1200 GHz. We observe two distinct signatures centered at ∼955 and 1015 GHz, and attribute them to the optically coupled particle vibrational resonance (surface phonon-polariton) of Bacillus spores. This demonstrates the potential of the THz attenuation signatures as "fingerprints" for label-free biomolecular detection.

  2. LCLS XTOD Attenuator System System Concept Report

    Energy Technology Data Exchange (ETDEWEB)

    Kishiyama, K; Roeben, M; Trent, J; Ryutov, D; Shen, S

    2006-04-12

    The attenuator system for the Linac Coherent Light Source (LCLS) X-ray Transport, Optics and Diagnostics (XTOD) system has been configured and analyzed by the Lawrence Livermore National Laboratory's New Technologies Engineering Division (NTED) as requested by the SLAC/LCLS program. The system layout, performance analyses and selection of the vacuum components are presented in this System Conceptual Review (SCR) report. Also included are the plans for prototype, procurement, mechanical integration, and the cost estimates.

  3. Attenuated Measles Virus as a Vaccine Vector

    OpenAIRE

    Zuniga, Armando; Wang, Zili; Liniger, Matthias; Hangartner, Lars; Caballero, Michael; Pavlovic, Jovan; Wild, Peter; Viret, Jean Francois; Glueck, Reinhard; Billeter, Martin A.; Naim, Hussein Y.

    2007-01-01

    Live attenuated measles virus (MV) vaccines have an impressive record of safety, efficacy and ability to induce life-long immunity against measles infection. Using reverse genetics technology, such negative-strand RNA viruses can now be rescued from cloned DNA. This technology allows the insertion of exogenous genes encoding foreign antigens into the MV genome in such a way that they can be expressed by the MV vaccine strain, without affecting virus structure, propagation and cell targeting. ...

  4. Lg Attenuation of the Western United States

    Science.gov (United States)

    Gallegos, A. C.; Ranasinghe, N. R.; Ni, J.; Sandvol, E. A.

    2014-12-01

    Lg waveforms recorded by EarthScope's Transportable Array (TA) are used to estimate Lg Q in the Western United States (WUS). Attenuation is calculated based on Lg spectral amplitudes filtered at a narrow band from 0.5 to 1.5 Hz with a central frequency of 1 Hz. The two-station and reverse two-station techniques were used to calculate Qo values. 398 events occurring from 2005 to 2009 and ranging from magnitude 3 to magnitude 6 were used in this study. The geometric spreading term can be determined by using a three-dimensional linear fit of the amplitude ratios versus epicentral distances to two stations. The slope of this line provides the geometric spreading term we use to calculate Lg Qo values of WUS. The results show high Q regions (low attenuation) corresponding to the Colorado Plateau (CP), the Rocky Mountains (RM), the Columbia Plateau (COP), and the Sierra Nevada Mountains (SNM). Regions of low Q (high attenuation) are seen along the Snake River Plain (SRP), the Rio Grande Rift (RGR), the Cascade Mountains (CM), and in east and west of the Basin and Range (BR) where tectonic activity is more active than the central part of the BR. A positive correlation between high heat flow, recent tectonic activity and Q was observed. Areas with low heat flow, thin sediment cover, and no recent tectonic activity were observed to have consistently high Q. These new models use two-station and reversed two-station methods and provide a comparison with previous studies and better constrain regions with high attenuation. This increase in detail can improve high frequency ground motion predictions of future large earthquakes for more accurate hazard assessment and improve overall understanding of the structure and assemblage of the WUS.

  5. Navigate the Digital Rapids

    Science.gov (United States)

    Lindsay, Julie; Davis, Vicki

    2010-01-01

    How can teachers teach digital citizenship when the digital landscape is changing so rapidly? How can teachers teach proper online social interactions when the students are outside their classroom and thus outside their control? Will encouraging students to engage in global collaborative environments land teachers in hot water? These are the…

  6. The Violent Content in Attenuated Psychotic Symptoms.

    Science.gov (United States)

    Marshall, Catherine; Deighton, Stephanie; Cadenhead, Kristin S; Cannon, Tyrone D; Cornblatt, Barbara A; McGlashan, Thomas H; Perkins, Diana O; Seidman, Larry J; Tsuang, Ming T; Walker, Elaine F; Woods, Scott W; Bearden, Carrie E; Mathalon, Daniel; Addington, Jean

    2016-08-30

    The relationship between psychosis and violence has typically focused on factors likely to predict who will commit violent acts. One unexplored area is violence in the content of subthreshold positive symptoms. The current aim was to conduct an exploratory analysis of violent content in the attenuated psychotic symptoms (APS) of those at clinical high risk of psychosis (CHR) who met criteria for attenuated psychotic symptom syndrome (APSS). The APS of 442 CHR individuals, determined by the Structured Interview for Prodromal Syndromes, were described in comprehensive vignettes. The content of these symptoms were coded using the Content of Attenuated Positive Symptoms Codebook. Other measures included clinical symptoms, functioning, beliefs and trauma. Individuals with violent content had significantly higher APS, greater negative beliefs about the self and others, and increased bullying. The same findings and higher ratings on anxiety symptoms were present when participants with self-directed violence were compared to participants with no violent content. Individuals reporting violent content differ in their clinical presentation compared to those who do not experience violent content. Adverse life events, like bullying, may impact the presence of violent content in APS symptoms. Future studies should explore violent content in relation to actual behavior. PMID:27259137

  7. Waves in fragmented geomaterials with impact attenuation

    Science.gov (United States)

    Dyskin, Arcady; Pasternak, Elena

    2016-04-01

    Attenuation of waves in geomaterials, such as seismic waves is usually attributed to energy dissipation due to the presence of viscous fluid and/or viscous cement between the constituents. In fragmented geomaterials such as blocky rock mass there is another possible source of energy dissipation - impacting between the fragments. This can be characterised by the coefficient of restitution, which is the ratio between the rotational velocities after and before the impact. In particular, this manifests itself in the process of mutual rotations of the fragments/blocks, whereby in the process of oscillation different ends of the contacting faces of the fragments are impacting. During the rotational oscillations the energy dissipation is concentrated in the neutral position that is the one in which the relative rotation between two fragments is zero. We show that in a simple system of two fragments this dissipation is equivalent, in a long run, to the presence of viscous damper between the fragments (the Voigt model of visco-elasticity). Generalisation of this concept to the material consisting of many fragments leads to a Voigt model of wave propagation where the attenuation coefficient is proportional to the logarithm of restitution coefficient. The waves in such a medium show slight dispersion caused by damping and strong dependence of the attenuation on the wave frequency.

  8. Novel Intriguing Strategies Attenuating to Sarcopenia

    Directory of Open Access Journals (Sweden)

    Kunihiro Sakuma

    2012-01-01

    Full Text Available Sarcopenia, the age-related loss of skeletal muscle mass, is characterized by a deterioration of muscle quantity and quality leading to a gradual slowing of movement, a decline in strength and power, increased risk of fall-related injury, and, often, frailty. Since sarcopenia is largely attributed to various molecular mediators affecting fiber size, mitochondrial homeostasis, and apoptosis, the mechanisms responsible for these deleterious changes present numerous therapeutic targets for drug discovery. Resistance training combined with amino acid-containing supplements is often utilized to prevent age-related muscle wasting and weakness. In this review, we summarize more recent therapeutic strategies (myostatin or proteasome inhibition, supplementation with eicosapentaenoic acid (EPA or ursolic acid, etc. for counteracting sarcopenia. Myostatin inhibitor is the most advanced research with a Phase I/II trial in muscular dystrophy but does not try the possibility for attenuating sarcopenia. EPA and ursolic acid seem to be effective as therapeutic agents, because they attenuate the degenerative symptoms of muscular dystrophy and cachexic muscle. The activation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α in skeletal muscle by exercise and/or unknown supplementation would be an intriguing approach to attenuating sarcopenia. In contrast, muscle loss with age may not be influenced positively by treatment with a proteasome inhibitor or antioxidant.

  9. Soil mass attenuation coefficient: Analysis and evaluation

    International Nuclear Information System (INIS)

    Highlights: • Experimental mass attenuation coefficient is affected by sample size. • Sample thickness larger than 9 cm presents the best results for 137Cs. • Sample thickness smaller than 5 cm presents the best results for 241Am. - Abstract: The mass attenuation coefficient (μ) is an important parameter to characterize the penetration and interaction of gamma-rays in the soil. Accurate determinations of μ are important to obtain representative values of soil physical properties by gamma-ray attenuation technique. In this study, the effect of collimator size (2–4 mm diameters) and absorber thickness (2–15 cm) on the experimental μ values of water and soils with different textures were investigated for 59.54 keV (241Am) and 661.1 keV (137Cs) gamma-ray sources. Theoretical results were calculated using the program XCOM. Experimental results were compared with theoretical ones showing a good correlation between methods. It was observed that for the 137Cs the best agreements between theoretical and experimental μ were obtained for sample thickness ⩾10 cm while for the 241Am were those obtained for thickness <5 cm for small collimators

  10. Seismic Attenuation Inversion with t* Using tstarTomog.

    Energy Technology Data Exchange (ETDEWEB)

    Preston, Leiph

    2014-09-01

    Seismic attenuation is defined as the loss of the seismic wave amplitude as the wave propagates excluding losses strictly due to geometric spreading. Information gleaned from seismic waves can be utilized to solve for the attenuation properties of the earth. One method of solving for earth attenuation properties is called t*. This report will start by introducing the basic theory behind t* and delve into inverse theory as it pertains to how the algorithm called tstarTomog inverts for attenuation properties using t* observations. This report also describes how to use the tstarTomog package to go from observed data to a 3-D model of attenuation structure in the earth.

  11. Blockade of Ets-1 attenuates epidermal growth factor-dependent collagen loss in human carotid plaque smooth muscle cells.

    Science.gov (United States)

    Rao, Velidi H; Rai, Vikrant; Stoupa, Samantha; Agrawal, Devendra K

    2015-09-15

    Although degradation of extracellular matrix by matrix metalloproteinases (MMPs) is thought to be involved in symptomatic (S) carotid plaques in atherosclerosis, the mechanisms of MMP expression are poorly understood. Here, we demonstrate that collagen loss in vascular smooth vessel cells (VSMCs) isolated from S plaques was induced by epidermal growth factor (EGF) through the activation of p38-MAPK and JNK-MAPK pathways. Inhibitors of p38-MAPK and JNK-MAPK signaling pathways downregulated the expression of MMP-1 and MMP-9. In addition, we examined whether v-ets erythroblastosis virus E26 oncogene homologue 1 (Ets-1), an important regulator of different genes, is involved in destabilizing S plaques in patients with carotid stenosis. We demonstrate that EGF induces Ets-1 expression and decreases interstitial and basement membrane collagen in vascular smooth muscle cells (VSMCs) from patients with carotid stenosis. Increased expression of MMP-1 and -9 and decreased collagen mRNA transcripts were also found in Ets-1-overexpressed VSMCs. Transfection with both dominant-negative form of Ets-1 and small interfering RNA blocked EGF-induced MMP-1 and -9 expressions and increased the mRNA transcripts for collagen I (α1) and collagen III (α1) in S compared with asymptomatic (AS) carotid plaques. Inhibitors of p38-MAPK (SB202190) and JNK-MAPK (SP600125) signaling pathways decreased the expression of Ets-1, MMP-1, and MMP-9 and increased collagen type I and III expression in EGF-treated VSMCs. This study provides a mechanistic insight into the role of Ets-1 in the plaque destabilization in patients with carotid stenosis involving p38-MAPK and JNK signaling pathways.

  12. NEAR INFRARED ELECTROCHROMIC VARIABLE OPTICAL ATTENUATOR FABRICATED BY LAYER-BY-LAYER ASSEMBLY*

    Institute of Scientific and Technical Information of China (English)

    Jia Zheng; Yi-jun Zheng; Xin-hua Wan

    2011-01-01

    An electrochromic variable optical attenuator (ECVOA) was fabricated by layer-by-layer (LBL) assembly of disodium N,N-bis(p-sulfonatophenyl)naphthalenedicarboximide (Naph-SO3Na) and common cationic polymer poly(diallyldimethylammonium) chloride (PDDA). The UV-Vis absorption spectra of the multilayer films revealed that approximately an equal amount of Naph-SO3Na was assembled in each deposition cycle. Upon one-electron reduction, multilayer films exhibited intense absorption around 452 nm and also a broad absorption band from 1200 nm to 1900 nm. Owing to the improved ionic conductivity, the optical attenuation at 1550 nm of the films showed rapid response time and reached 1.3 dB/μm within 5 s. These results indicate that layer-by-layer assembly could be an effective method for the preparation of ECVOA operating in near infrared region.

  13. Determination of the attenuation map in emission tomography

    CERN Document Server

    Zaidi, H

    2002-01-01

    Reliable attenuation correction methods for quantitative emission computed tomography (ECT) require accurate delineation of the body contour and often necessitate knowledge of internal anatomical structure. Two broad classes of methods have been used to calculate the attenuation map referred to as "transmissionless" and transmission-based attenuation correction techniques. While calculated attenuation correction belonging to the first class of methods is appropriate for brain studies, more adequate methods must be performed in clinical applications where the attenuation coefficient distribution is not known a priori, and for areas of inhomogeneous attenuation such as the chest. Measured attenuation correction overcomes this problem and utilizes different approaches to determine this map including transmission scanning, segmented magnetic resonance images or appropriately scaled X-ray CT scans acquired either independently on separate or simultaneously on multimodality imaging systems. Combination of data acqu...

  14. Erraticity of rapidity gaps

    International Nuclear Information System (INIS)

    The use of rapidity gaps is proposed as a measure of the spatial pattern of an event. When the event multiplicity is low, the gaps between neighboring particles carry far more information about an event than multiplicity spikes, which may occur very rarely. Two moments of the gap distribution are suggested for characterizing an event. The fluctuations of those moments from event to event are then quantified by an entropy-like measure, which serves to describe erraticity. We use ECOMB to simulate the exclusive rapidity distribution of each event, from which the erraticity measures are calculated. The dependences of those measures on the order q of the moments provide single-parameter characterizations of erraticity. (c) 2000 The American Physical Society

  15. Rapid Detection of Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    David Perlin

    2005-08-14

    Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development

  16. New Rapid Spore Assay

    Science.gov (United States)

    Kminek, Gerhard; Conley, Catharine

    2012-07-01

    The presentation will detail approved Planetary Protection specifications for the Rapid Spore Assay for spacecraft components and subsystems. Outlined will be the research and studies on which the specifications were based. The research, funded by ESA and NASA/JPL, was conducted over a period of two years and was followed by limited cleanroom studies to assess the feasibility of this assay during spacecraft assembly.

  17. Tiber Personal Rapid Transit

    Directory of Open Access Journals (Sweden)

    Diego Carlo D'agostino

    2011-02-01

    Full Text Available The project “Tiber Personal Rapid Transit” have been presented by the author at the Rome City Vision Competition1 2010, an ideas competition, which challenges architects, engineers, designers, students and creatives individuals to develop visionary urban proposals with the intention of stimulating and supporting the contemporary city, in this case Rome. The Tiber PRT proposal tries to answer the competition questions with the definition of a provocative idea: a Personal Rapid transit System on the Tiber river banks. The project is located in the central section of the Tiber river and aims at the renewal of the river banks with the insertion of a Personal Rapid Transit infrastructure. The project area include the riverbank of Tiber from Rome Transtevere RFI station to Piazza del Popolo, an area where main touristic and leisure attractions are located. The intervention area is actually no used by the city users and residents and constitute itself a strong barrier in the heart of the historic city.

  18. Rapid frequency scan EPR.

    Science.gov (United States)

    Tseitlin, Mark; Rinard, George A; Quine, Richard W; Eaton, Sandra S; Eaton, Gareth R

    2011-08-01

    In rapid frequency scan EPR with triangular scans, sufficient time must be allowed to insure that the magnetization in the x, y plane decays to baseline at the end of the scan, which typically is about 5T(2) after the spins are excited. To permit relaxation of signals excited toward the extremes of the scan the total scan time required may be much longer than 5T(2). However, with periodic, saw-tooth excitation, the slow-scan EPR spectrum can be recovered by Fourier deconvolution of data recorded with a total scan period of 5T(2), even if some spins are excited later in the scan. This scan time is similar to polyphase excitation methods. The peak power required for either polyphase excitation or rapid frequency scans is substantially smaller than for pulsed EPR. The use of an arbitrary waveform generator (AWG) and cross loop resonator facilitated implementation of the rapid frequency scan experiments reported here. The use of constant continuous low B(1), periodic excitation waveform, and constant external magnetic field is similar to polyphase excitation, but could be implemented without the AWG that is required for polyphase excitation. PMID:21664848

  19. Quantification of numerical aperture-dependence of the OCT attenuation coefficient (Conference Presentation)

    Science.gov (United States)

    Peinado, Liliana M.; Bloemen, Paul R.; Almasian, Mitra; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-03-01

    .1155/2011/825629. [3] Jung W and Boppart S. Optical coherence tomography for rapid tissue screening and directed histological sectioning. Anal Cell Pathol (Amst). 2012; 35(3): 129-143. [4] R. Wessels et al. Optical coherence tomography in vulvar intraepithelial neoplasia. J Biomed Opt 2012 Nov; 17(11): 116022. [5] Faber D, van der Meer F, Aalders M, van Leeuwen T. Quantitative measurement of attenuation coefficients of weakly scattering media using optical coherence tomography. OPT EXPRESS 2004; 12 (19): 4353-43. [6] Thrane L, Yura HT, and Andersen PE. Analysis of optical coherence tomography systems based on the extended Huygens-Fresnel principle. JOSA 2000; 17(3): 484-490.

  20. Attenuation of Road Traffic Noise by Vegetation in Urban Spaces

    Directory of Open Access Journals (Sweden)

    Jasmina Radosavljević

    2015-09-01

    Full Text Available The last decades of the 20 th century and the beginning of the 21 st century have been characterized by rapid urban growth of cities, which resulted in overcrowding and the lack of land. The aftermath of such circumstances is the construction of many buildings near the main roads and the bus stations, which causes population exposure to significant levels of noise. In the cities aimed at maintaining sustainable urban environment, greenery is a key element that can be used to approach this issue successfully. Green facades, also known as vertical greenery systems, are becoming increasingly popular in urban areas. Vertical green systems on the facade walls, low belts of green vegetation and trees of different heights, widths and lengths contribute to reducing the level of traffic noise. The ability of greenery to attenuate noise is greater with the increasing frequency of traffic. This paper describes the effects of certain types of vegetation on traffic noise reduction, depending on the parameters such as: the type of vegetation, the dimensions of the green belt, the distance from the noise source, frequency range, etc.

  1. Attenuation contrast between biomolecular and inorganic materials at terahertz frequencies

    Science.gov (United States)

    Chan, T. L. J.; Bjarnason, J. E.; Lee, A. W. M.; Celis, M. A.; Brown, E. R.

    2004-09-01

    Wideband photomixing spectroscopy is used in the present work to contrast the transmission spectra of macromolecules commonly found in biomaterials such as potato starch, wheat flour and cornstarch, and proteins (Cytoplex™), and micromolecules such as sucrose, and inorganic materials such as sodium bicarbonate, and calcium sulfate. Powdered samples were measured at 0.1-0.5THz frequencies. A significant difference in attenuation is found between these samples. At 300GHz starch shows an absorption coefficient of ˜6cm-1 whereas Cytoplex shows 1-3cm-1, while inorganic micromolecules have ˜1cm-1. The absorption in starch increases rapidly with frequency tending to follow a power law α =fn with n typically between 1.5 and 2.0. In contrast, protein materials display a slower dependence on frequency with n between 1.0 and 1.5, and simple molecules show the least n among all three categories. The difference between these ubiquitous macromolecular and micromolecular materials is explained in terms of water content and molecular structure.

  2. Right-Rapid-Rough

    Science.gov (United States)

    Lawrence, Craig

    2003-01-01

    IDEO (pronounced 'eye-dee-oh') is an international design, engineering, and innovation firm that has developed thousands of products and services for clients across a wide range of industries. Its process and culture attracted the attention of academics, businesses, and journalists around the world, and are the subject of a bestselling book, The Art of Innovation by Tom Kelley. One of the keys to IDEO's success is its use of prototyping as a tool for rapid innovation. This story covers some of IDEO's projects, and gives reasons for why they were successful.

  3. Rapid Frequency Scan EPR

    OpenAIRE

    Tseitlin, Mark; Rinard, George A.; Quine, Richard W.; Eaton, Sandra S.; Eaton, Gareth R.

    2011-01-01

    In rapid frequency scan EPR with triangular scans, sufficient time must be allowed to insure that the magnetization in the x,y plane decays to baseline at the end of the scan, which typically is about 5 T2 after the spins are excited. To permit relaxation of signals excited toward the extremes of the scan the total scan time required may be much longer than 5 T2. However, with periodic, saw-tooth excitation, the slow-scan EPR spectrum can be recovered by Fourier deconvolution of data recorded...

  4. Rapidly progressive tabetic neurosyphilis

    Institute of Scientific and Technical Information of China (English)

    赖伟红; 薛华忠; 韩国柱

    2003-01-01

    Since the sexually transmitted diseases were recognized as a public health problem in China during the early 1980's, the incidence of syphilis has gradually increased. Though there have been case reports of clinical variants of neurosyphilis, including syphilitic cerebrospinal meningitis or meningomyelitis and meningovascular syphilis, occurring in different regions of China,1-3 tabes dorsalis or tabetic neurosyphilis has not yet been reported in China. Here, we report a young man with rapidly progressive tabetic neurosyphilis admitted to our hospital in October 1999.

  5. Computer-aided codon-pairs deoptimization of the major envelope GP5 gene attenuates porcine reproductive and respiratory syndrome virus.

    Science.gov (United States)

    Ni, Yan-Yan; Zhao, Zhao; Opriessnig, Tanja; Subramaniam, Sakthivel; Zhou, Lei; Cao, Dianjun; Cao, Qian; Yang, Hanchun; Meng, Xiang-Jin

    2014-02-01

    Synthetic attenuated virus engineering (SAVE) is an emerging technology that enables rapid attenuation of viruses. In this study, by using SAVE we demonstrated rapid attenuation of an arterivirus, porcine reproductive and respiratory syndrome virus (PRRSV). The major envelope GP5 gene of PRRSV was codon-pair deoptimized aided by a computer algorithm. The codon-pair deoptimized virus, designated as SAVE5 with a deoptimized GP5 gene, was successfully rescued in vitro. The SAVE5 virus replicated at a lower level in vitro with a significant decrease of GP5 protein expression compared to the wild-type PRRSV VR2385 virus. Pigs experimentally infected with the SAVE5 virus had significantly lower viremia level up to 14 days post-infection as well as significantly reduced gross and histological lung lesions when compared to wild-type PRRSV VR2385 virus-infected pigs, indicating the attenuation of the SAVE5 virus. This study proved the feasibility of rapidly attenuating PRRSV by SAVE.

  6. Obtaining the mass attenuation coefficient of the wood to a beam of gamma-ray of 241Am

    International Nuclear Information System (INIS)

    Full text: The quality of wood produced in Brazil reforestation has been the subject of many discussions in the Forestry Sector. SeEKXing to produce a rapid growth and wood quality, the Forestry Sector, found in Applied Nuclear Physics, a precise method of determining the density of wood known as ad hoc technique of attenuation of gamma-ray. The radioisotope used in this technique is that it has a picture 241Am peak of 59.6 keV gamma-ray. This work has the objective of determining the mass attenuation coefficient of wood of the genus Eucalyptus for 241Am radioisotope. We used 324 samples of wood from six different treatments: a seminal of Eucalyptus grandis; two clones of E. grandis; three clones of the hybrid E. grandis x E. urophylla. The same assay was used for the six treatments. It was determined the basic density of the samples by the method of immersion in water and then the basic density was converted into apparent density in the moisture equilibrium and it was determined the attenuation coefficient of mass. Preliminary results showed that the attenuation coefficient of mass did not vary between treatments, and its average value 0.1822 ± 0.0015. It was to here that the attenuation coefficient of mass in the wood of the genus Eucalyptus in moisture equilibrium can be constant. (author)

  7. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yujun [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States); Li, Jian-Dong [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Yan, Chen, E-mail: Chen_Yan@urmc.rochester.edu [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  8. Exercise Training During Bed Rest Attenuates Deconditioning

    Science.gov (United States)

    Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

    1995-01-01

    A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  9. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    International Nuclear Information System (INIS)

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis

  10. Towards a Global Upper Mantle Attenuation Model

    Science.gov (United States)

    Karaoglu, Haydar; Romanowicz, Barbara

    2015-04-01

    Global anelastic tomography is crucial for addressing the nature of heterogeneity in the Earth's interior. The intrinsic attenuation manifests itself through dispersion and amplitude decay. These are contaminated by elastic effects such as (de)focusing and scattering. Therefore, mapping anelasticity accurately requires separation of elastic effects from the anelastic ones. To achieve this, a possible approach is to try and first predict elastic effects through the computation of seismic waveforms in a high resolution 3D elastic model, which can now be achieved accurately using numerical wavefield computations. Building upon the recent construction of such a whole mantle elastic and radially anisotropic shear velocity model (SEMUCB_WM1, French and Romanowicz, 2014), which will be used as starting model, our goal is to develop a higher resolution 3D attenuation model of the upper mantle based on full waveform inversion. As in the development of SEMUCB_WM1, forward modeling will be performed using the spectral element method, while the inverse problem will be treated approximately, using normal mode asymptotics. Both fundamental and overtone time domain long period waveforms (T>60s) will be used from a dataset of over 200 events observed at several hundred stations globally. Here we present preliminary results of synthetic tests, exploring different iterative inversion strategies.

  11. Live attenuated influenza vaccine--a review.

    Science.gov (United States)

    Gasparini, R; Amicizia, D; Lai, P L; Panatto, D

    2011-09-01

    Owing to the variability of influenza viruses, vaccine composition needs to be up-dated annually. As many variables can influence their efficacy, vaccines are still considered "sub-optimal". Many studies have been carried out in recent years to improve vaccines. In particular, researchers and vaccine-producing corporations have focused on developing a live vaccine. Among the candidate vaccines, the strain developed by Maassab has recently been licensed in the USA and Europe, after extensive investigation. This vaccine is safe and well tolerated, and has shown very good genetic stability. Although vaccine recipients are able to spread the virus, transmission to close contacts is practically non-existent. Studies on cold-adapted attenuated influenza vaccines have demonstrated that such vaccines are effective, and sometimes more effective than inactivated influenza vaccines. Cold-adapted attenuated influenza vaccines therefore appear to be an important weapon against influenza. However, a more widespread use of these vaccines is to be recommended, especially in children, as the more acceptable way of administration can favour parental compliance.

  12. The Rapid Transient Surveyor

    CERN Document Server

    Baranec, Christoph; Wright, Shelley A; Tonry, John; Tully, R Brent; Szapudi, István; Takamiya, Marianne; Hunter, Lisa; Riddle, Reed; Chen, Shaojie; Chun, Mark

    2016-01-01

    The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of ~4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z < 0.1 universe. RTS will comprise an upgraded version of the Robo-AO laser AO system and will respond quickly to target-of-opportunity events, minimizing the time between discovery and characterization. RTS will acquire simultaneous-multicolor images with a...

  13. Determination of uranium in aqueous attenuating samples using gamma-ray spectrometry.

    Science.gov (United States)

    Agarwal, Chhavi; Kalsi, P C; Mhatre, A; Goswami, A

    2007-12-01

    In the present work, a method for determination of uranium concentration in aqueous solution in standard geometry from attenuating samples has been developed based on modification of the empirical approach of Venkataraman and Croft [2003. Determination of plutonium mass using gamma-ray spectrometry. Nucl. Instrum. Methods Phys. Res. A 505, 527-530]. The method makes use of the multiple gamma (gamma)-rays emitted by 235U and depends on the empirical relation between apparent mass of the sample and gamma-ray energy. It was possible to determine uranium concentration in the range of 12-400mg/ml rapidly by this method without applying transmission corrections. PMID:17768057

  14. Applying Echoes Mean Frequency Shift for Attenuation Imaging in Tissue

    Science.gov (United States)

    Litniewski, J.; Klimonda, Z.; Nowicki, A.

    The purpose of this study was to develop the attenuation parametric imaging technique and to apply it for in vivo characterization of tissue. Local attenuation coefficient was determined by evaluating the frequency downshift that encounters the amplitude spectrum of the interrogating ultrasonic pulse during propagation in the absorbing tissue. Operation and accuracy of the processing methods were verified by assessing the size-independent region of interest (ROI) for attenuation determination and calculating the attenuation coefficient distribution for experimentally recorded tissue-phantom scattered waveforms. The Siemens Antares scanner equipped with Ultrasound Research Interface unit allowing for direct radiofrequency (RF) signals recording was used for B-scan imaging of the tissue- mimicking phantom in vitro and liver in vivo. RF data were processed to determine attenuation coefficient along the B-scan lines. Also, the preliminary studies of backscattered signals from skin recorded using a skin scanner were performed to calculate parametric-attenuation images.

  15. A wideband IM3 cancellation technique for CMOS attenuators

    NARCIS (Netherlands)

    Cheng, W.; Oude Alink, M.S.; Annema, A.J.; Wienk, G.J.M.; Nauta, B.

    2012-01-01

    A highly linear P attenuator system using a wideband IM3 cancellation technique is presented that provides 4 discrete attenuation levels with 6dB spacing for DC-5GHz. For the whole band, S11<-14dB, attenuation flatness<1.6dB, +10dBm input P1dB and +26dBm IIP3 are achieved. For the TV band (0.1Gz-1.2

  16. Tickle me, I think I might be dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid dreams

    OpenAIRE

    Jennifer Michelle Windt; Dominic eHarkness; Bigna eLenggenhager

    2014-01-01

    The contrast between self- and other-produced tickles, as a special case of sensory attenuation for self-produced actions, has long been a target of empirical research. While in standard wake states it is nearly impossible to tickle oneself, there are interesting exceptions. Notably, participants awakened from REM (rapid eye movement-) sleep dreams are able to tickle themselves. So far, however, the question of whether it is possible to tickle oneself and be tickled by another in the dream st...

  17. Attenuation characteristics of ground motions in northern China

    Institute of Scientific and Technical Information of China (English)

    黄玉龙; 赵兴权; 罗奇峰

    2002-01-01

    Four recently developed attenuation models are calibrated by using a very limited amount of strong motion data recorded in China. The research shows that the attenuation characteristics of the earthquake shaking in northern China are similar to those in the western US. The supporting evidence includes Q factors, preliminary results of kappa values, stress drop,shear wave velocity profile in the shallow earth crust, areas enclosed by the isoseismals of Modified Mercalli Intensity V. From these comparisons of different attenuation models, it is recommended that the Crouse and McGuire spectral attenuation model could possibly be used for northern China.

  18. Importance of Attenuation Correction (AC for Small Animal PET Imaging

    Directory of Open Access Journals (Sweden)

    Henrik H. El Ali

    2012-10-01

    Full Text Available The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7 were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II. CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%, for kidneys 20 ± 1% (19–21%, and for bladder 18 ± 3% (15–21%. The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction.

  19. [Usefulness of attenuation correction with transmission source in myocardial SPECT].

    Science.gov (United States)

    Murakawa, Keizo; Katafuchi, Tetsuro; Nishimura, Yoshihiro; Enomoto, Naoyuki; Sago, Masayoshi; Oka, Hisashi

    2006-01-20

    Attenuation correction in SPECT has been used for uniformly absorptive objects like the head. On the other hand, it has seldom been applied to nonuniform absorptive objects like the heart and surrounding lungs because of the difficulty and inaccuracy of data processing. However, since attenuation correction using a transmission source recently became practical, we were able to apply this method to a nonuniform absorptive object. Therefore, we evaluated the usefulness of this attenuation correction system with a transmission source in myocardial SPECT. The dose linearity, defect/normal ratio using a myocardial phantom, and myocardial count distribution in clinical cases was examined with and without the attenuation correction system. We found that all data processed with attenuation correction were better than those without attenuation correction. For example, in myocardial count distribution, while there was a difference between men and women without attenuation correction, which was considered to be caused by differences in body shape, after processing with attenuation correction, myocardial count distribution was almost the same in all cases. In conclusion, these results suggested that attenuation correction with a transmission source was useful in myocardial SPECT.

  20. Attenuation of ground-motion spectral amplitudes in southeastern Australia

    Science.gov (United States)

    Allen, T.I.; Cummins, P.R.; Dhu, T.; Schneider, J.F.

    2007-01-01

    A dataset comprising some 1200 weak- and strong-motion records from 84 earthquakes is compiled to develop a regional ground-motion model for southeastern Australia (SEA). Events were recorded from 1993 to 2004 and range in size from moment magnitude 2.0 ??? M ??? 4.7. The decay of vertical-component Fourier spectral amplitudes is modeled by trilinear geometrical spreading. The decay of low-frequency spectral amplitudes can be approximated by the coefficient of R-1.3 (where R is hypocentral distance) within 90 km of the seismic source. From approximately 90 to 160 km, we observe a transition zone in which the seismic coda are affected by postcritical reflections from midcrustal and Moho discontinuities. In this hypocentral distance range, geometrical spreading is approximately R+0.1. Beyond 160 km, low-frequency seismic energy attenuates rapidly with source-receiver distance, having a geometrical spreading coefficient of R-1.6. The associated regional seismic-quality factor can be expressed by the polynomial: log Q(f) = 3.66 - 1.44 log f + 0.768 (log f)2 + 0.058 (log f)3 for frequencies 0.78 ??? f ??? 19.9 Hz. Fourier spectral amplitudes, corrected for geometrical spreading and anelastic attenuation, are regressed with M to obtain quadratic source scaling coefficients. Modeled vertical-component displacement spectra fit the observed data well. Amplitude residuals are, on average, relatively small and do not vary with hypocentral distance. Predicted source spectra (i.e., at R = 1 km) are consistent with eastern North American (ENA) Models at low frequencies (f less than approximately 2 Hz) indicating that moment magnitudes calculated for SEA earthquakes are consistent with moment magnitude scales used in ENA over the observed magnitude range. The models presented represent the first spectral ground-motion prediction equations develooed for the southeastern Australian region. This work provides a useful framework for the development of regional ground-motion relations

  1. Rapid automated nuclear chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, R.A.

    1979-05-31

    Rapid Automated Nuclear Chemistry (RANC) can be thought of as the Z-separation of Neutron-rich Isotopes by Automated Methods. The range of RANC studies of fission and its products is large. In a sense, the studies can be categorized into various energy ranges from the highest where the fission process and particle emission are considered, to low energies where nuclear dynamics are being explored. This paper presents a table which gives examples of current research using RANC on fission and fission products. The remainder of this text is divided into three parts. The first contains a discussion of the chemical methods available for the fission product elements, the second describes the major techniques, and in the last section, examples of recent results are discussed as illustrations of the use of RANC.

  2. JINR rapid communications

    International Nuclear Information System (INIS)

    The present collection of rapid communications from JINR, DUBNA, contains eight separate records on symmetry in modern physics (dedicated to the 100th anniversary of the birth of academician V.A.Fock), the double φ-meson production investigation on the Serpukhov accelerator, two-leptonic η-meson decays and SUSY without R parity, charge form factors and alpha-cluster internal structure of 12C, increasing of muon-track reconstruction efficiency in ME1/1 Dubna prototype for the CMS/LHC, study of photon-structure function F2γ in the reaction e+e- → e+e- + hadrons at LEP2, jets reconstruction possibility in pAu and AuAu interactions at STAR RHIC and high-vacuum nondispersable gas absorber

  3. JINR rapid communications

    International Nuclear Information System (INIS)

    The present collection of rapid communications from JINR, Dubna, contains twelve separate records on pseudoscalar form factor from inverse pion electroproduction and the first radial pion excitation, chiral and parity anomalies at finite temperature and density, the canonical form of an elastoplastic model of nuclear fusion, the peculiarities of the reactions of heavy and superheavy element synthesis within the dinuclear system concept, a study of the photon structure function F2γ in the reaction e+e-→e+e- + hadrons at LEP1 and LEP2, tritons for the study of the charge-exchange reactions with the LHE streamer chamber: status and some possibilities, nonlinear dynamics in nuclotron, current transformers and optical diagnostic monitor of nuclotron beam, the design features of the LHE JINR nuclotron internal target stations, a system of graphics digitization (SGD), numeric simulation of thermal treatment of metal surface by means of high current ion beam

  4. JINR rapid communications

    International Nuclear Information System (INIS)

    The present collection of rapid communications from JINR, Dubna, contains nine separate reports on effects arising from charged particles overcoming of the light velocity barrier, deformable templates for circle recognition, scintillation detectors for precise time measurements, atomic form factors and incoherent scattering functions of atoms and ions with the number of electrons N ≤ 10, experimental set-up ANOMALON for measurement of relativistic nuclear fragmentation cross sections, superconducting dipole magnet for ALICE dimuon arm spectrometer, analysis of transverse mass dependence of Bose-Einstein correlation radii using the DELPHI data, low-energy theorem in softly broken supersymmetry and study of the characteristics of particles in reactions π-, p, d, He, C + C with the total disintegration on carbon nucleus

  5. JINR rapid communications

    International Nuclear Information System (INIS)

    The present collection of rapid communications from JINR, Dubna, contains seven separate records on measurements of the total cross section difference ΔσL(np) at 1.59, 1.79, and 2.20 GeV, to the estimation of angular distributions of double charged spectator fragments in nucleus-nucleus interactions at superhigh energies, simulation dE/dx analysis results for silicon inner tracking system of ALICE set-up at LHC accelerator, high-multiplicity processes, triggering of high-multiplicity events using calorimetry, ORBIT-3.0 - a computer code for simulation and correction of the closed orbit and first turn in synchrotrons and determination of memory performance

  6. Higgsstrahlung at forward rapidities

    CERN Document Server

    Pasechnik, Roman; Potashnikova, Irina

    2014-01-01

    We discuss the inclusive and single diffractive heavy flavor (top and bottom) production in association with the Higgs boson at forward rapidities in proton-proton collisions at the LHC. The calculations are performed in the framework of the phenomenological dipole approach, which automatically accounts for the absorptive corrections induced by soft interactions, i.e. for the gap survival effects at the amplitude level. Major differential observables including the realistic ATLAS detector constraints are considered. The forward inclusive and diffractive Higgsstrahlung processes are generated essentially by excitation of the valence or sea quarks in the proton. The single diffractive Higgsstrahlung off top quarks is found to dominate compared to the loop-induced mechanism at sufficiently large Higgs boson transverse momenta. The Higgsstrahlung processes offer a direct and precise measurement of Higgs-top and, possibly, Higgs-bottom Yukawa couplings at the LHC, as well as the studies of the intrinsic heavy flav...

  7. Rapid Diagnosis of Malaria

    Directory of Open Access Journals (Sweden)

    Clinton K. Murray

    2009-01-01

    Full Text Available Malaria's global impact is expansive and includes the extremes of the healthcare system ranging from international travelers returning to nonendemic regions with tertiary referral medical care to residents in hyperendemic regions without access to medical care. Implementation of prompt and accurate diagnosis is needed to curb the expanding global impact of malaria associated with ever-increasing antimalarial drug resistance. Traditionally, malaria is diagnosed using clinical criteria and/or light microscopy even though both strategies are clearly inadequate in many healthcare settings. Hand held immunochromatographic rapid diagnostic tests (RDTs have been recognized as an ideal alternative method for diagnosing malaria. Numerous malaria RDTs have been developed and are widely available; however, an assortment of issues related to these products have become apparent. This review provides a summary of RDT including effectiveness and strategies to select the ideal RDT in varying healthcare settings.

  8. Rapid automated nuclear chemistry

    International Nuclear Information System (INIS)

    Rapid Automated Nuclear Chemistry (RANC) can be thought of as the Z-separation of Neutron-rich Isotopes by Automated Methods. The range of RANC studies of fission and its products is large. In a sense, the studies can be categorized into various energy ranges from the highest where the fission process and particle emission are considered, to low energies where nuclear dynamics are being explored. This paper presents a table which gives examples of current research using RANC on fission and fission products. The remainder of this text is divided into three parts. The first contains a discussion of the chemical methods available for the fission product elements, the second describes the major techniques, and in the last section, examples of recent results are discussed as illustrations of the use of RANC

  9. Rapid shallow breathing index.

    Science.gov (United States)

    Karthika, Manjush; Al Enezi, Farhan A; Pillai, Lalitha V; Arabi, Yaseen M

    2016-01-01

    Predicting successful liberation of patients from mechanical ventilation has been a focus of interest to clinicians practicing in intensive care. Various weaning indices have been investigated to identify an optimal weaning window. Among them, the rapid shallow breathing index (RSBI) has gained wide use due to its simple technique and avoidance of calculation of complex pulmonary mechanics. Since its first description, several modifications have been suggested, such as the serial measurements and the rate of change of RSBI, to further improve its predictive value. The objective of this paper is to review the utility of RSBI in predicting weaning success. In addition, the use of RSBI in specific patient populations and the reported modifications of RSBI technique that attempt to improve the utility of RSBI are also reviewed. PMID:27512505

  10. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  11. Rapid prototyping and time compression

    OpenAIRE

    Chatwin, Chris

    2000-01-01

    Rapid Prototyping - manufacture by layering processes: Stereolithography Selective Layer Sintering (SLS) Laminated Object Manufacture (LOM) Solid Ground Curing Small batch programmable rapid manufacture with lasers Micro-Engineering – Prototyping and Manufacture Additive - fabrication Subtractive – machining

  12. Rapid Refresh (RAP) [20 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  13. Rapid Refresh (RAP) [13 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  14. Rapid geophysical surveyor

    International Nuclear Information System (INIS)

    The Rapid Geophysical Surveyor (RGS) is a system designed to rapidly and economically collect closely-spaced geophysical data used for characterization of Department of Energy (DOE) waste sites. Geophysical surveys of waste sites are an important first step in the remediation and closure of these sites; especially older sties where historical records are inaccurate and survey benchmarks have changed due to refinements in coordinate controls and datum changes. Closely-spaced data are required to adequately differentiate pits, trenches, and soil vault rows whose edges may be only a few feet from each other. A prototype vehicle designed to collect magnetic field data was built at the Idaho national Engineering Laboratory (INEL) during the summer of 1992. The RGS was one of several projects funded by the Buried Waste Integrated Demonstration (BWID) program. This vehicle was demonstrated at the Subsurface Disposal Area (SDA) within the Radioactive Waste Management Complex (RWMC) on the INEL in September of 1992. Magnetic data were collected over two areas in the SDA, with a total survey area of about 1.7 acres. Data were collected at a nominal density of 2 1/2 inches along survey lines spaced 1 foot apart. Over 350,000 data points were collected over a 6 day period corresponding to about 185 man-days using conventional ground survey techniques. This report documents the design and demonstration of the RGS concept including the presentation of magnetic data collected at the SDA. The surveys were able to show pit and trench boundaries and determine details of their spatial orientation never before achieved

  15. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE

  16. The Applications for the Calculation and Optimization of Passive Optical Networks Attenuation Characteristics

    Directory of Open Access Journals (Sweden)

    Pavel Lafata

    2010-01-01

    Full Text Available The passive optical networks represent modern and promising solution to meet the increasing demands on the transmission speed in access networks. These optical networks consist only of passive optical components, essential role play mainly the passive optical splitters. Therefore, it is not possible to perform additional adjustments with the optical signal, such as its amplifying, dropping, routing, etc. It is necessary in early stage of planning the optical network to comply with its parameters for its proper operation, especially the values of total attenuation, optical return loss, delay, etc. It is therefore necessary to accomplish the detailed analysis and the calculation of total attenuation characteristics of proposed optical network. The program for the purposes of rapid calculation of the passive optical network attenuation was designed. It supports various network topologies and it enables to enter initial parameters of optical network. The outputs in the tabular form also include the assessment of the suitability of proposed optical network for the different variants of passive optical networks.

  17. Definition of Genetically Distinct Attenuation Mechanisms in Naturally Virulence-Attenuated Listeria monocytogenes by Comparative Cell Culture and Molecular Characterization

    OpenAIRE

    Roberts, Angela; Chan, Yvonne; Wiedmann, Martin

    2005-01-01

    Listeria monocytogenes is a foodborne pathogen able to cause serious disease in humans and animals. Not all isolates are equally pathogenic, however, and several isolates have been characterized as naturally virulence attenuated. We sought to identify the genetic basis of natural virulence attenuation using cell culture assays and molecular techniques. By comparing the phenotypes of naturally virulence-attenuated isolates to those of defined virulence gene mutants in plaque, cytotoxicity, and...

  18. Turbulence attenuation by large neutrally buoyant particles

    CERN Document Server

    Cisse, Mamadou; Gibert, Mathieu; Bodenschatz, Eberhard; Bec, Jeremie

    2015-01-01

    Turbulence modulation by inertial-range-size, neutrally-buoyant particles is investigated experimentally in a von K\\'arm\\'an flow. Increasing the particle volume fraction $\\Phi_\\mathrm{v}$, maintaining constant impellers Reynolds number attenuates the fluid turbulence. The inertial-range energy transfer rate decreases as $\\propto\\Phi_\\mathrm{v}^{2/3}$, suggesting that only particles located on a surface affect the flow. Small-scale turbulent properties, such as structure functions or acceleration distribution, are unchanged. Finally, measurements hint at the existence of a transition between two different regimes occurring when the average distance between large particles is of the order of the thickness of their boundary layers.

  19. Attenuation of neutrons through ducts and labyrinths

    CERN Document Server

    Mauro, Egidio

    2009-01-01

    Monte Carlo simulations have been performed for the attenuation of neutron radiation produced at proton accelerators through ducts and labyrinths of various design, and the results are compared with the predictions made by analytical expressions available in the literature. The results show that the so-called universal transmission curves are an appropriate and simple tool applicable in many situations, when the radiation source is not in direct view of the duct mouth. This is not the case for point sources located in front of the duct. The simulations showed that it is not possible to apply the same models because the transmission factor is strongly dependent on the cross-sectional area of the duct. A universal expression has been derived to estimate the neutron transmission through a straight duct of length d and cross-sectional area A in direct view of the source, which only depends on A and on a small set of numerical coefficients.

  20. Attenuation of Shocks through Porous Media

    Science.gov (United States)

    Lind, Charles A.; Cybyk, Bohdan Z.; Boris, Jay P.

    1998-11-01

    Structures designed to mitigate the effects of blast and shock waves are important for both accidental and controlled explosions. The net effect of these mitigating structures is to reduce the strength of the transmitted shock thereby reducing the dynamic pressure loading on nearby objects. In the present study, the attenuation of planar blast and shock waves by passage through structured media is numerically studied with the FAST3D model. The FAST3D model is a state-of-the-art, portable, three-dimensional computational fluid dynamics model based on Flux-Corrected Transport and uses the Virtual Cell Embedding algorithm for simulating complex geometries. The effects of media placement, spacing, orientation, and area blockage are parametrically studied to enhance the understanding of the complex processes involved and to determine ways to minimize the adverse effects of these blast waves.

  1. Core disgust is attenuated by ingroup relations.

    Science.gov (United States)

    Reicher, Stephen D; Templeton, Anne; Neville, Fergus; Ferrari, Lucienne; Drury, John

    2016-03-01

    We present the first experimental evidence to our knowledge that ingroup relations attenuate core disgust and that this helps explain the ability of groups to coact. In study 1, 45 student participants smelled a sweaty t-shirt bearing the logo of another university, with either their student identity (ingroup condition), their specific university identity (outgroup condition), or their personal identity (interpersonal condition) made salient. Self-reported disgust was lower in the ingroup condition than in the other conditions, and disgust mediated the relationship between condition and willingness to interact with target. In study 2, 90 student participants smelled a sweaty target t-shirt bearing either the logo of their own university, another university, or no logo, with either their student identity or their specific university identity made salient. Walking time to wash hands and pumps of soap indicated that disgust was lower where the relationship between participant and target was ingroup rather than outgroup or ambivalent (no logo). PMID:26903640

  2. Gas sensor with attenuated drift characteristic

    Science.gov (United States)

    Chen, Ing-Shin [Danbury, CT; Chen, Philip S. H. [Bethel, CT; Neuner, Jeffrey W [Bethel, CT; Welch, James [Fairfield, CT; Hendrix, Bryan [Danbury, CT; Dimeo, Jr., Frank [Danbury, CT

    2008-05-13

    A sensor with an attenuated drift characteristic, including a layer structure in which a sensing layer has a layer of diffusional barrier material on at least one of its faces. The sensor may for example be constituted as a hydrogen gas sensor including a palladium/yttrium layer structure formed on a micro-hotplate base, with a chromium barrier layer between the yttrium layer and the micro-hotplate, and with a tantalum barrier layer between the yttrium layer and an overlying palladium protective layer. The gas sensor is useful for detection of a target gas in environments susceptible to generation or incursion of such gas, and achieves substantial (e.g., >90%) reduction of signal drift from the gas sensor in extended operation, relative to a corresponding gas sensor lacking the diffusional barrier structure of the invention

  3. Attenuation of ultrasonic waves in rolled metals

    Science.gov (United States)

    Yang, Liyong; Turner, Joseph A.

    2004-12-01

    Scattering of ultrasonic waves in polycrystals with texture is studied in this article. The attenuations of the three wave modes are determined as a function of dimensionless frequency and propagation direction, respectively, for given orientation distribution coefficients (ODCs). The calculation is done in the case of a statistically orthorhombic sample made up of cubic crystallites. The wave propagation and scattering model is formulated by the Dyson equation using an anisotropic Green's function approach. Within the limits of the first-order smoothing approximation, the Dyson equation is solved in the spatial Fourier transform domain. The results presented are shown to be directional dependent, frequency dependent, and especially dependent on the texture coefficients (ODCs) for the quasilongitudinal and two quasishear waves. The theoretical results presented may be used to improve the understanding of the microstructure during recrystallization processes. .

  4. Attenuation of species abundance distributions by sampling.

    Science.gov (United States)

    Shimadzu, Hideyasu; Darnell, Ross

    2015-04-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  5. A miniaturized reconfigurable broadband attenuator based on RF MEMS switches

    Science.gov (United States)

    Guo, Xin; Gong, Zhuhao; Zhong, Qi; Liang, Xiaotong; Liu, Zewen

    2016-07-01

    Reconfigurable attenuators are widely used in microwave measurement instruments. Development of miniaturized attenuation devices with high precision and broadband performance is required for state-of-the-art applications. In this paper, a compact 3-bit microwave attenuator based on radio frequency micro-electro-mechanical system (RF MEMS) switches and polysilicon attenuation modules is presented. The device comprises 12 ohmic contact MEMS switches, π-type polysilicon resistive attenuation modules and microwave compensate structures. Special attention was paid to the design of the resistive network, compensate structures and system simulation. The device was fabricated using micromachining processes compatible with traditional integrated circuit fabrication processes. The reconfigurable attenuator integrated with RF MEMS switches and resistive attenuation modules was successfully fabricated with dimensions of 2.45  ×  4.34  ×  0.5 mm3, which is 1/1000th of the size of a conventional step attenuator. The measured RF performance revealed that the attenuator provides 10-70 dB attenuation at 10 dB intervals from 0.1-20 GHz with an accuracy better than  ±1.88 dB at 60 dB and an error of less than 2.22 dB at 10 dB. The return loss of each state of the 3-bit attenuator was better than 11.95 dB (VSWR  <  1.71) over the entire operating band.

  6. The Rapid Transient Surveyor

    Science.gov (United States)

    Baranec, Christoph; Tonry, John; Wright, Shelley; Tully, R. Brent; Lu, Jessica R.; Takamiya, Marianne Y.; Hunter, Lisa

    2016-01-01

    The next decade of astronomy will be dominated by large area surveys (see the detailed discussion in the Astro-2010 Decadal survey and NRC's recent OIR System Report). Ground-based optical transient surveys, e.g., LSST, ZTF and ATLAS and space-based exoplanet, supernova, and lensing surveys such as TESS and WFIRST will join the Gaia all-sky astrometric survey in producing a flood of data that will enable leaps in our understanding of the universe. There is a critical need for further characterization of these discoveries through high angular resolution images, deeper images, spectra, or observations at different cadences or periods than the main surveys. Such follow-up characterization must be well matched to the particular surveys, and requires sufficient additional observing resources and time to cover the extensive number of targets.We describe plans for the Rapid Transient Surveyor (RTS), a permanently mounted, rapid-response, high-cadence facility for follow-up characterization of transient objects on the U. of Hawai'i 2.2-m telescope on Maunakea. RTS will comprise an improved robotic laser adaptive optics system, based on the prototype Robo-AO system (formerly at the Palomar 1.5-m and now at the Kitt Peak 2.2-m telescope), with simultaneous visible and near-infrared imagers as well as a near-infrared integral field spectrograph (R~100, λ = 850 - 1830 nm, 0.15″ spaxels, 8.7″×6.0″ FoV). RTS will achieve an acuity of ~0.07″ in visible wavelengths and < 0.16″ in the near infrared leading to an increase of the infrared point-source sensitivity against the sky background by a factor of ~9, crucial for efficient near-infrared spectroscopy.RTS will allow us to map the dark matter distribution in the z < 0.1 local universe with ten times better accuracy and precision than previous experiments. ATLAS will discover several thousand SNIae per year, measuring SNIa peak brightness, and decline rates, while RTS will measure reddening by dust, confirm SN type and

  7. What makes ribosome-mediated transcriptional attenuation sensitive to amino acid limitation?

    Directory of Open Access Journals (Sweden)

    Johan Elf

    2005-06-01

    Full Text Available Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal determines the expression of the amino acid biosynthetic operon (response. The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the

  8. What makes ribosome-mediated transcriptional attenuation sensitive to amino Acid limitation?

    Directory of Open Access Journals (Sweden)

    2005-06-01

    Full Text Available Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal determines the expression of the amino acid biosynthetic operon (response. The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the

  9. What makes ribosome-mediated transcriptional attenuation sensitive to amino acid limitation?

    Science.gov (United States)

    Elf, Johan; Ehrenberg, Måns

    2005-06-01

    Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal) determines the expression of the amino acid biosynthetic operon (response). The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated) can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the same amino acid. We

  10. Rapidly Evolving Giant Dermatofibroma

    Directory of Open Access Journals (Sweden)

    K. J. Lang

    2010-01-01

    Full Text Available Dermatofibroma, also known as “fibrous histiocytoma”, is a benign dermal or subcutaneous poorly circumscribed proliferation of spindle-shaped fibroblasts and macrophages in the dermis. Although it is commonly present as a brownish nodule the legs of females, it may also arise on the upper extremities, trunk, and rarely on the head. The exact pathogenesis is unclear. However, it is widely believed that the originating insult to the dermis is a folliculitis, an arthropod bite, or an unspecified initial inflammatory condition. Giant dermatofibromas of greater than 5 cm in diameter are rare, with only 22 cases reported in the literature. We present a case of a rapidly evolving pedunculated mass in the groin of a male patient. Histological examination confirmed this to be a giant dermatofibroma. Though this specimen cannot is not confirmed as such, the cellular subtype is sometimes present as a larger lesion with anecdotal reports of local recurrence and distant metastases. The clinical and radiological features which were somewhat suspicious of malignancy are considered in the context of the definitive pathological diagnosis of a benign lesion.

  11. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  12. Rapid Evaporation of microbubbles

    Science.gov (United States)

    Gautam, Jitendra; Esmaeeli, Asghar

    2008-11-01

    When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

  13. Rapidly rotating red giants

    CERN Document Server

    Gehan, Charlotte; Michel, Eric

    2016-01-01

    Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, which behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the id...

  14. Implementation of Enhanced Attenuation at the DOE Mound Site OU-1 Landfill: Accelerating Progress and Reducing Costs

    Energy Technology Data Exchange (ETDEWEB)

    Hooten, Gwendolyn [U.S. Department of Energy, Office of Legacy Management; Cato, Rebecca [Navarro Research and Engineering; Looney, Brian [Savannah River National Laboratory, Aiken, SC

    2016-03-06

    At the US Department of Energy (DOE), Office of Legacy Management, Mound, Ohio, Site, chlorinated organic contaminants (cVOCs) originating from the former solid-waste landfill have impacted groundwater in Operable Unit 1 (OU-1). The baseline groundwater remedy was groundwater pump and treat (P&T). Since the source materials have been removed from the landfill, the Mound core team, which consists of DOE, US Environmental Protection Agency (US EPA), Ohio EPA, and other stakeholders, is assessing the feasibility of switching from the active P&T remedy to a passive attenuation-based remedy. Toward this end, an enhanced attenuation (EA) strategy based on the creation of structured geochemical zones was developed. This EA strategy addresses the residual areas of elevated cVOCs in soil and groundwater while minimizing the rebound of groundwater concentrations above regulatory targets (e.g., maximum contaminant levels [MCLs]) and avoiding plume expansion while the P&T system is turned off. The EA strategy has improved confidence and reduced risk on the OU-1 groundwater transition path to monitored natural attenuation (MNA). To better evaluate the EA strategy, DOE is conducting a field demonstration to evaluate the use of edible oils to enhance the natural attenuation processes. The field demonstration is designed to determine whether structured geochemical zones can be established that expedite the attenuation of cVOCs in the OU-1 groundwater. The EA approach at OU-1 was designed based on “structured geochemical zones” and relies on groundwater flow through a succession of anaerobic and aerobic zones. The anaerobic zones stimulate relatively rapid degradation of the original solvent source compounds (e.g., cVOCs such as tetrachloroethene [PCE] and trichloroethene [TCE]). The surrounding aerobic areas encourage relatively rapid degradation of daughter products (such as dichloroethene [DCE] and vinyl chloride [VC]) as well as enhanced cometabolism of TCE resulting from

  15. Periportal low-attenuation: a CT sign of lymphatic obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Kim, Chong Soo; Yang, Doo Hyun; Lee, Sang Yong; Lee, Young Whan; Chung, Gyung Ho; Han, Young Min; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National University College of Medicine, Jeonju (Korea, Republic of)

    1995-07-15

    Periportal low attenuation, defined as a low attenuation rim around the portal vein and its branches which is seen on contrast material-enhanced CT scans, has been described in a variety of conditions. We tried to document that lymphatic obstruction is one of the major cause of periportal low attenuation. We retrospectively analyzed 57 cases of periportal low attenuation of abdominal CT scans and also reviewed the surgical records in 32 cases. Lymph node enlargement in the hepatoduodenal ligament which is a main lymphatic channel from the liver were analyzed the calculated the ratio of the transeverse diameter between the inferior vena cava and the aorta at the level of right adrenal gland. After complete surgical interruption of the lymphatic drainage from the liver in a dog, follow up CT scans were obtained and correlated with pathologic findings. Fifty patients (88%) had underlying disease which could cause impairment of lymphatic drainage. Periportal low attenuation was identified in several clinical conditions, including surgical lymph node dissection, lymphadenopathy in the hepatoduodenal ligament, blunt trauma. In animal model, CT scan showed prominent periportal low attenuation at 5 days after surgery. Histologic examination revealed numerous dilated lymphatic vessels and a marked lymphedema in the connective tissues surrounding the portal vein and its major branches. One of the major cause of periportal low attenuation was impaired lymphatic drainage and periportal low attenuation corresponding to the numerous dilated lymphatic vessels and a marked lymphedema in the connective tissues surrounding the portal vein and its major branches.

  16. Attenuation law of explosive stress wave in damaged rock mass

    Institute of Scientific and Technical Information of China (English)

    CHEN Shi-hai; CUI Xin-zhuang

    2001-01-01

    The attenuation regularity of explosion stress waves in damaged rocks is discussed according to physical and geometric attenuation of waves in this pa per. The relation between numerical decrement and damaged parameter is given and the results have an important significance to design and control blasting effec t accurately in a concrete rock.

  17. Attenuation law of explosive stress wave in damaged rock mass

    Institute of Scientific and Technical Information of China (English)

    陈士海; 崔新壮

    2001-01-01

    The attenuation regularity of explosion stress waves in damaged rocks is discussed according to physical and geometric attenuation of waves in this paper. The relation between numerical decrement and damaged parameter is given and the results have an important significance to design and control blasting effect accurately in a concrete rock.

  18. 16 CFR 1203.17 - Impact attenuation test.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Impact attenuation test. 1203.17 Section... SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... the acceleration of the test headform during impact. Acceleration is measured with a...

  19. Wave attenuation in mangroves; a quantitative approach to field observations

    NARCIS (Netherlands)

    Horstman, E.M.; Dohmen-Janssen, C.M.; Narra, P.M.F.; Berg, van den N.J.F.; Siemerink, M.; Hulscher, S.J.M.H.

    2014-01-01

    Coastal mangroves, dwelling at the interface between land and sea, provide an important contribution to reducing risk from coastal hazards by attenuating incident waves and by trapping and stabilizing sediments. This paper focusses on relations between vegetation densities, wave attenuation rates, s

  20. Doxycycline Attenuated Pulmonary Fibrosis Induced by Bleomycin in Mice

    OpenAIRE

    Fujita, Masaki; Ye, Qing; Ouchi, Hiroshi; Harada, Eiji; Inoshima, Ichiro; Kuwano, Kazuyoshi; Nakanishi, Yoichi

    2006-01-01

    The administration of doxycycline prior to bleomycin in mice attenuated pulmonary fibrosis. Bronchoalveolar neutrophil influx and gelatinase activity, but not caseinolytic activity, were attenuated by doxycycline. Established fibrosis was not affected by doxycycline. Thus, doxycycline might be useful for slowing down pulmonary fibrosis by biological activity other than antibacterial activity.

  1. Flux attenuation at NREL's High-Flux Solar Furnace

    Science.gov (United States)

    Bingham, Carl E.; Scholl, Kent L.; Lewandowski, Allan A.

    1994-10-01

    The High-Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL) has a faceted primary concentrator and a long focal-length-to-diameter ratio (due to its off-axis design). Each primary facet can be aimed individually to produce different flux distributions at the target plane. Two different types of attenuators are used depending on the flux distribution. A sliding-plate attenuator is used primarily when the facets are aimed at the same target point. The alternate attenuator resembles a venetian blind. Both attenuators are located between the concentrator and the focal point. The venetian-blind attenuator is primarily used to control the levels of sunlight failing on a target when the primary concentrators are not focused to a single point. This paper will demonstrate the problem of using the sliding-plate attenuator with a faceted concentrator when the facets are not aimed at the same target point. We will show that although the alternate attenuator necessarily blocks a certain amount of incoming sunlight, even when fully open, it provides a more even attenuation of the flux for alternate aiming strategies.

  2. X-Ray Form Factor, Attenuation and Scattering Tables

    Science.gov (United States)

    SRD 66 X-Ray Form Factor, Attenuation and Scattering Tables (Web, free access)   This database collects tables and graphs of the form factors, the photoabsorption cross section, and the total attenuation coefficient for any element (Z <= 92).

  3. The attenuation anisotropy of mudstones and shales in subsurface formations

    Institute of Scientific and Technical Information of China (English)

    SHI Ge; DENG Jixin

    2005-01-01

    We have measured the relationships in the laboratorial condition between the attenuation in three samples of mudstones and shales as well as two samples of layered sandstones and the alteration in direction, confining pressure and pore fluid. The relative contributions of different attenuation mechanisms are also discussed. Studies show that the attenuation in dry and saturated samples is strongly related to pressure and direction. The attenuation coefficient of P-wave propagating parallel to bedding (PH) is less than that of P-wave propagating vertical to bedding (PV), while the attenuation coefficient of S-wave both propagating and vibrating parallel to bedding (SH) and that of S-wave propagating vertical to bedding while vibrating parallel to bedding (SV1) are less than that of S-wave propagating parallel to bedding while vibrating vertical to bedding (SV). Under oil saturated conditions, the Biot flow attenuation acts as the dominant mechanism for waves propagating parallel to bedding, while the frame anelastic attenuation and squirt flow attenuation seem to play important roles in condition of propagation vertical to bedding.

  4. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær;

    2012-01-01

    concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%), for kidneys 20 ± 1% (19...

  5. A Precision Variable, Double Prism Attenuator for CO(2) Lasers.

    Science.gov (United States)

    Oseki, T; Saito, S

    1971-01-01

    A precision, double prism attenuator for CO(2) lasers, calibrated by its gap capacitance, was constructed to evaluate its possible use as a standard for attenuation measurements. It was found that the accuracy was about 0.1 dB with a dynamic range of about 40 dB.

  6. Broad beam and narrow beam attenuation in Lipowitz's metal.

    Science.gov (United States)

    el-Khatib, E E; Podgorsak, E B; Pla, C

    1987-01-01

    Attenuation properties of Lipowitz's metal have been studied for narrow and broad beams of cobalt-60 gamma rays and 4-10 MV x-rays. The measured transmitted fraction for geometries used in radiotherapy depends on the field size and depth of measurement. Therefore a calculation of dose for partially attenuated beams based on narrow beam attenuation coefficients can cause large errors in dosimetry. Our simple calculation of transmitted fractions based on primary attenuation and scattered radiation agrees quite well with the measured data for therapeutic geometries. Also given is a table for linear, mass attenuation, and mass energy absorption coefficients of Lipowitz's metal in the photon energy range from 10 keV to 10 MeV. PMID:3104738

  7. Attenuation correction for the NIH ATLAS small animal PET scanner

    CERN Document Server

    Yao, Rutao; Liow, JeihSan; Seidel, Jurgen

    2003-01-01

    We evaluated two methods of attenuation correction for the NIH ATLAS small animal PET scanner: 1) a CT-based method that derives 511 keV attenuation coefficients (mu) by extrapolation from spatially registered CT images; and 2) an analytic method based on the body outline of emission images and an empirical mu. A specially fabricated attenuation calibration phantom with cylindrical inserts that mimic different body tissues was used to derive the relationship to convert CT values to (I for PET. The methods were applied to three test data sets: 1) a uniform cylinder phantom, 2) the attenuation calibration phantom, and 3) a mouse injected with left bracket **1**8F right bracket FDG. The CT-based attenuation correction factors were larger in non-uniform regions of the imaging subject, e.g. mouse head, than the analytic method. The two methods had similar correction factors for regions with uniform density and detectable emission source distributions.

  8. Efficacy of esmolol administration at different time intervals in attenuating hemodynamic response to tracheal intubation

    Directory of Open Access Journals (Sweden)

    S K Singhal

    2010-01-01

    Full Text Available Background: Laryngoscopy and endotracheal intubation are known to cause increase in both arterial blood pressure and heart rate. Several strategies have been evolved to blunt the haemodynamic response to tracheal intubation but each method has its own advantages and disadvantages. Esmolol, a cardio selective Beta -1 blocking drug, can alleviate some of these problems. Esmolol, when administered parenterally, exhibits rapid onset and a short duration of action due to its rapid clearance by red blood cell esterases. Hence we conducted the present study to evaluate the efficacy and optimum time of single bolus esmolol administration in attenuating hypertensive- tachycardiac response to laryngoscopy and tracheal intubation. Materials and Methods: The randomized double blind prospective study was conducted in 60 patients, in the age group of 20-40 years, of both sexes, belonging to American Society of Anaesthesiologists (ASA physical status class I or II and scheduled for elective surgery requiring endotracheal intubation and general anaesthesia. The efficacy and optimum time of single bolus esmolol administration in attenuating hypertensive - tachycardiac response to laryngoscopy and tracheal intubation was evaluated. Patients in group I (n=20 received bolus administration of injection esmolol 1.5 mg/kg intravenously (iv 90 seconds before intubation; in group II (n=20 three minutes before intubation and in group III (n=20 six minutes before intubation. Results: There was no clinical and statistically significant variation in heart rate in group I and II at different time intervals of the study period but in group III heart rate increased significantly one minute after tracheal intubation. (P0.05 Conclusion: To conclude, single intravenous bolus dose of esmolol (1.5 mg/kg is safe and more effective in attenuating haemodynamic response to laryngoscopy and tracheal intubation when administered three minutes prior to intubation.

  9. Determination of mass attenuation coefficient in wood and leaves of typical trees by gamma-ray attenuation technique

    International Nuclear Information System (INIS)

    Using an 241 Am source the mass attenuation coefficient of different woods and leaves of typical species of the Atlantic Forest were measured. The results for natural wood, dry wood and dry leaves indicate that the variation is very small among different species. However, woods present a higher attenuation than leaves, both depending on their water content. (author). 10 refs., 3 figs., 1 tab

  10. Backscatter and attenuation characterization of ventricular myocardium

    Science.gov (United States)

    Gibson, Allyson Ann

    2009-12-01

    This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium. In this Dissertation, integrated backscatter and attenuation analyses were performed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The hearts were interrogated using a 50 MHz transducer that enabled finer spatial resolution than could be achieved at more typical clinical frequencies. Ultrasonic data analyses demonstrated different patterns and relative levels of backscatter and attenuation from the myocardium of the left ventricle and the right ventricle. Ultrasonic data of adult human hearts were acquired with a clinical imaging system and quantified by their magnitude and time delay of cyclic variation of myocardial backscatter. The results were analyzing using Bayes Classification and ROC analysis to quantify potential advantages of using a combination of two features of cyclic variation of myocardial backscatter over using only one or the other feature to distinguish between groups of subjects. When the subjects were classified based on hemoglobin A1c, the homeostasis model assessment of insulin resistance, and the ratio of triglyceride to high-density lipoprotein-cholesterol, differences in the magnitude and normalized time delay of cyclic variation of myocardial backscatter were observed. The cyclic variation results also suggested a trend toward a larger area under the ROC curve when information from magnitude and time delay of cyclic variation is combined using Bayes classification than when

  11. Photochemical Attenuation of Pesticides in Prairie Potholes

    Science.gov (United States)

    Zeng, T.; Arnold, W. A.

    2013-12-01

    Prairie potholes are small, shallow, glacially-derived wetlands scattered across a vast region extending from Midwestern United States into south central Canada known as the Prairie Pothole Region (PPR). They constitute one of the largest inland wetland systems on Earth and play a prominent role in sustaining the regional biodiversity and productivity. Throughout the PPR, historic and contemporary conversion of native prairie for agriculture resulted in a pronounced loss of potholes. Remaining potholes have become interspersed within a matrix of agricultural landscape and trap nonpoint source pollutants such as pesticides from adjacent farmland, which has raised concerns regarding negative impacts on the water quality of downstream water bodies. The fate and persistence of pesticides in potholes, however, remains largely unexplored. Prairie potholes are typically characterized by shallow depth (i.e., large photic zone) and high levels of dissolved organic matter (DOM), making them ideal for photochemical reactions. In this context, we collected pothole water samples from North Dakota to investigate the rates and mechanisms of sunlight-induced attenuation of pesticides. The photodegradation kinetics and pathways of sixteen pesticides in the pothole water were monitored under both simulated and natural sunlight. For most pesticides, photolysis accelerated in the pothole water relative to the buffer control, which pointed to the importance of photosensitized processes (i.e., indirect photolysis). Upon solar irradiation, a mixture of photochemically produced reactive intermediates (PPRIs), such as carbonate radical, hydroxyl radical, singlet oxygen, and triplet-excited state DOM, formed in the pothole water. The major pathways through which pesticides degraded were inferred from the relative contribution attributable to specific PPRIs via quencher experiments. Different classes of pesticides exhibited contrasting photochemical behavior, but singlet oxygen and triplet

  12. Silibinin attenuates allergic airway inflammation in mice

    International Nuclear Information System (INIS)

    Highlights: ► Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. ► Silibinin reduces the levels of various cytokines into the lung of allergic mice. ► Silibinin prevents the development of airway hyperresponsiveness in allergic mice. ► Silibinin suppresses NF-κB transcriptional activity. -- Abstract: Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-κB) pathway. Because NF-κB activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-κB activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-κB activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  13. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    BHALLA VYOMA; SINGH DEVRAJ; JAIN S K; KUMAR RAJ

    2016-06-01

    The present paper deals with the theoretical calculation of mechanical and thermophysical properties of rare-earth monoarsenides, XAs (X: Np, Pu, Th and U) using elastic constants as the input parameters. These second- and third-order elastic constants (SOECs and TOECs) are determinedin the temperature range 100–500K using Coulomb and Born–Mayer potential upto second nearest neighbours. In order to provide the link between mechanical and dynamical behaviour of crystals, parameters such as Young’s modulus, bulk modulus, Poisson’s ratio etc. are also calculated.In addition, the Cauchy relationship is obeyed by the chosen monoarsenides and are fairly anisotropic, which results in the measurement of longitudinal and shear wave velocities along $\\langle100 \\rangle$, $\\langle110\\rangle$ and $\\langle 111\\rangle$ directions. The toughness/fracture $(G/BT)$ ratio is greater than 0.60, which implies that XAs compounds are brittle at room temperature. Further, the Debye temperature is computed using Debye average velocity as the input parameter. It helps in the characterization of lattice vibrations of a solid. In this work, ultrasonic attenuation due to phonon–phonon interaction$\\alpha/f^2_{\\rm p−p}$ and thermoelastic loss $\\alpha/f ^{2}$th are computed for XAs from 100 to 500K using Mason’s theory. It further helps in evaluating the microstructural properties of the chosen materials. The obtained results indicate that XAs is mechanically stable and are compared with data availablein the literature.

  14. Silibinin attenuates allergic airway inflammation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yun Ho [Department of Anatomy, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Jin, Guang Yu [Department of Radiology, Yanbian University Hospital, YanJi 133002 (China); Guo, Hui Shu [Centralab, The First Affiliated Hospital of Dalian Medical University, Dalian 116011 (China); Piao, Hong Mei [Department of Respiratory Medicine, Yanbian University Hospital, YanJi 133000 (China); Li, Liang chang; Li, Guang Zhao [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China); Lin, Zhen Hua [Department of Pathology, Yanbian University School of Basic Medical Sciences, YanJi 133000 (China); Yan, Guang Hai, E-mail: ghyan@ybu.edu.cn [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. Black-Right-Pointing-Pointer Silibinin reduces the levels of various cytokines into the lung of allergic mice. Black-Right-Pointing-Pointer Silibinin prevents the development of airway hyperresponsiveness in allergic mice. Black-Right-Pointing-Pointer Silibinin suppresses NF-{kappa}B transcriptional activity. -- Abstract: Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-{kappa}B) pathway. Because NF-{kappa}B activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-{kappa}B activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-{kappa}B activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  15. Atorvastatin attenuates oxidative stress in Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Cai Zhiyou; Yan Yong; Wang Yonglong

    2008-01-01

    Objective: To investigate serum level of SOD, MDA, ox-LDL, AchE and Ach in AD, to study atorvastatin influence on serum level of SOD, MDA, ox-LDL, AchE and Acb in AD and its neuroprotection mechanisms. Methods Subjects were divided into: normal blood lipid level group with Alzheimer's disease (A), higher blood lipid level group with Alzheimer's disease (AH), normal blood lipid level Alzheimer's disease group with atorvastatin treeatment (AT),higher blood lipid level Alzheimer's disease group with atorvastatin treeatment(AHT). Ox-LDL was measured by enzyme linked immunosorbent assay; SOD, MDA, ox-LDL, AchE, Ach and blood lipid level in AD was measured by biochemistry. Results: The serum level of MDA, AchE in AH group after atorvastatin treatment is lower ;The serum level of SOD, Ach in AH group is more increased than that of in A group; The serum level of ox-LDL in AH, A groups is lower than that of in A group; The dementia degree is lower after atorvastatin treatment. Conclusion: Atorvastatin can decrease serum level of MDA, AchE and ox-LDL, and increase that of SOD, Acb, and attenuate dementia symptom in AD, especially, with hyperlipemia. The hypothesis of atorvastatin neuroprotection is concluded that atorvastatin may restrain free radical reaction and retard oxidation in AD.

  16. Minocycline Attenuates Iron-Induced Brain Injury.

    Science.gov (United States)

    Zhao, Fan; Xi, Guohua; Liu, Wenqaun; Keep, Richard F; Hua, Ya

    2016-01-01

    Iron plays an important role in brain injury after intracerebral hemorrhage (ICH). Our previous study found minocycline reduces iron overload after ICH. The present study examined the effects of minocycline on the subacute brain injury induced by iron. Rats had an intracaudate injection of 50 μl of saline, iron, or iron + minocycline. All the animals were euthanized at day 3. Rat brains were used for immunohistochemistry (n = 5-6 per each group) and Western blotting assay (n = 4). Brain swelling, blood-brain barrier (BBB) disruption, and iron-handling proteins were measured. We found that intracerebral injection of iron resulted in brain swelling, BBB disruption, and brain iron-handling protein upregulation (p < 0.05). The co-injection of minocycline with iron significantly reduced iron-induced brain swelling (n = 5, p < 0.01). Albumin, a marker of BBB disruption, was measured by Western blot analysis. Minocycline significantly decreased albumin protein levels in the ipsilateral basal ganglia (p < 0.01). Iron-handling protein levels in the brain, including ceruloplasmin and transferrin, were reduced in the minocycline co-injected animals. In conclusion, the present study suggests that minocycline attenuates brain swelling and BBB disruption via an iron-chelation mechanism. PMID:26463975

  17. Statins attenuate polymethylmethacrylate-mediated monocyte activation.

    LENUS (Irish Health Repository)

    Laing, Alan J

    2012-02-03

    BACKGROUND: Periprosthetic osteolysis precipitates aseptic loosening of components, increases the risk of periprosthetic fracture and, through massive bone loss, complicates revision surgery and ultimately is the primary cause for failure of joint arthroplasty. The anti-inflammatory properties of HMG-CoA reductase inhibitors belonging to the statin family are well recognized. We investigated a possible role for status in initiating the first stage of the osteolytic cycle, namely monocytic activation. METHODS: We used an in vitro model of the human monocyte\\/macrophage inflammatory response to poly-methylmethacrylate (PMMA) particles after pretreat-ing cells with cerivastatin, a potent member of the statin family. Cell activation based upon production of TNF-alpha and MCP-1 cytokines was analyzed and the intracellular Raf-MEK-ERK signal transduction pathway was evaluated using western blot analysis, to identify its role in cell activation and in any cerivastatin effects observed. RESULTS: We found that pretreatment with cerivastatin significantly abrogates the production of inflammatory cytokines TNF-alpha and MCP-1 by human monocytes in response to polymethylmethacrylate particle activation. This inflammatory activation and attenuation appear to be mediated through the intracellular Raf-MEK-ERK pathway. INTERPRETATION: We propose that by intervening at the upstream activation stage, subsequent osteoclast activation and osteolysis can be suppressed. We believe that the anti-inflammatory properties of statins may potentially play a prophylactic role in the setting of aseptic loosening, and in so doing increase implant longevity.

  18. Rapid Robot Design Validation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies will create a comprehensive software infrastructure for rapid validation of robotic designs. The software will support push-button validation...

  19. Rapid Robot Design Validation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies will create a comprehensive software infrastructure for rapid validation of robot designs. The software will support push-button validation...

  20. Broadband Lg Attenuation Modeling in the Middle East

    Energy Technology Data Exchange (ETDEWEB)

    Pasyanos, M E; Matzel, E M; Walter, W R; Rodgers, A J

    2008-08-21

    We present a broadband tomographic model of Lg attenuation in the Middle East derived from source- and site-corrected amplitudes. Absolute amplitude measurements are made on hand-selected and carefully windowed seismograms for tens of stations and thousands of crustal earthquakes resulting in excellent coverage of the region. A conjugate gradient method is used to tomographically invert the amplitude dataset of over 8000 paths over a 45{sup o} x 40{sup o} region of the Middle East. We solve for Q variation, as well as site and source terms, for a wide range of frequencies ranging from 0.5-10 Hz. We have modified the standard attenuation tomography technique to more explicitly define the earthquake source expression in terms of the seismic moment. This facilitates the use of the model to predict the expected amplitudes of new events, an important consideration for earthquake hazard or explosion monitoring applications. The attenuation results have a strong correlation to tectonics. Shields have low attenuation, while tectonic regions have high attenuation, with the highest attenuation at 1 Hz is found in eastern Turkey. The results also compare favorably to other studies in the region made using Lg propagation efficiency, Lg/Pg amplitude ratios and two-station methods. We tomographically invert the amplitude measurements for each frequency independently. In doing so, it appears the frequency-dependence of attenuation is not compatible with the power law representation of Q(f), an assumption that is often made.

  1. Rain Attenuation Prediction for Terrestrial Microwave Link in Bangladesh

    Directory of Open Access Journals (Sweden)

    HOSSAIN Sakir

    2014-05-01

    Full Text Available Rain attenuation is a major shortcoming of microwave transmission. As a subtropical country, Bangladesh is one of the highest rainy areas of the world. Thus, designing a terrestrial microwave link is a serious challenge to the engineers. In this paper, the annual rain rate and monthly variation of rate are predicted for different percentage of time of the year from the measured rainfall data. Using ITU rain model for terrestrial microwave communication, the rain attenuation is predicted for five major cities of Bangladesh, namely Dhaka, Chittagong, Rajshahi, Sylhet, and Khulna. It is found that rain attenuation is the most severe in Sylhet and least in Rajshahi. The attenuation is estimated for different frequency and polarization. A horizontally polarized signal encounters 15% more rain attenuation than that of vertically polarized signal. It is also found that attenuation in Rajshahi is about 20% lesser than that in Sylhet. Thus, the horizontally polarized transmission in Rajshahi experiences about 5% less attenuation than the vertically polarized transmission in Sylhet.

  2. Met-myoglobin formation, accumulation, degradation, and myoglobin oxygenation monitoring based on multiwavelength attenuance measurement in porcine meat

    Science.gov (United States)

    Nguyen, Thien; Phan, Kien Nguyen; Lee, Jee-Bum; Kim, Jae Gwan

    2016-05-01

    We propose a simple, rapid, and nondestructive method to investigate formation, accumulation, and degradation of met-myoglobin (met-Mb) and myoglobin oxygenation from the interior of porcine meat. For the experiment, color photos and attenuance spectra of porcine meat (well-bled muscle, fat, and mixed) were collected daily to perform colorimetric analysis and to obtain the differences of attenuance between 578 and 567 nm (A578-A567) and between 615 and 630 nm (A630-A615), respectively. Oxy-, deoxy-, and met-myoglobin concentration changes over storage time were also calculated using Beer-Lamberts' law with reflectance intensities at 557, 582, and 630 nm. The change of A578-A567 was well matched with the change of myoglobin oxygenation, and the change of A630-A615 corresponded well with the formation and degradation of met-Mb. In addition, attenuation differences, A578-A567 and A630-A615, were able to show the formation of met-Mb earlier than colorimetric analysis. Therefore, the attenuance differences between wavelengths can be indicators for estimating myoglobin oxygenation and met-Mb formation, accumulation, and degradation, which enable us to design a simple device to monitor myoglobin activities in porcine meat.

  3. Molecular basis of live-attenuated influenza virus.

    Directory of Open Access Journals (Sweden)

    Wen He

    Full Text Available Human influenza is a seasonal disease associated with significant morbidity and mortality. The most effective means for controlling infection and thereby reducing morbidity and mortality is vaccination with a three inactivated influenza virus strains mixture, or by intranasal administration of a group of three different live attenuated influenza vaccine strains. Comparing to the inactivated vaccine, the attenuated live viruses allow better elicitation of a long-lasting and broader immune (humoral and cellular response that represents a naturally occurring transient infection. The cold-adapted (ca influenza A/AA/6/60 (H2N2 (AA ca virus is the backbone for the live attenuated trivalent seasonal influenza vaccine licensed in the United States. Similarly, the influenza A components of live-attenuated vaccines used in Russia have been prepared as reassortants of the cold-adapted (ca H2N2 viruses, A/Leningrad/134/17/57-ca (Len/17 and A/Leningrad/134/47/57-ca (Len/47 along with virulent epidemic strains. However, the mechanism of temperature-sensitive attenuation is largely elusive. To understand how modification at genetic level of influenza virus would result in attenuation of human influenza virus A/PR/8/34 (H1N1,A/PR8, we investigated the involvement of key mutations in the PB1 and/or PB2 genes in attenuation of influenza virus in vitro and in vivo. We have demonstrated that a few of residues in PB1 and PB2 are critical for the phenotypes of live attenuated, temperature sensitive influenza viruses by minigenome assay and real-time PCR. The information of these mutation loci could be used for elucidation of mechanism of temperature-sensitive attenuation and as a new strategy for influenza vaccine development.

  4. Seismic attenuation: Laboratory measurements in fluid saturated rocks

    Science.gov (United States)

    Subramaniyan, Shankar; Madonna, Claudio; Tisato, Nicola; Saenger, Erik; Quintal, Beatriz

    2014-05-01

    Seismic wave attenuation could be used as an indicator of reservoir fluids due to its dependence on rock and fluid properties. Over the past 30 years, many laboratory methodologies to study attenuation in rocks have been employed, such as ultrasonic (MHz), resonant bar (kHz) and forced oscillation methods in the low frequency range (0.01-100Hz) (Tisato & Madonna 2012; Madonna & Tisato 2013). Forced oscillation methods have gained prominence over time as the frequency range of measurements correspond to that of field seismic data acquired for oil/gas exploration. These experiments measure attenuation as the phase shift between the applied stress (sinusoidal) and measured strain. Since the magnitudes of measured phase shifts are quite low (Q-1 ~0.01-0.1) and the amplitudes of strain applied to the rock samples are of the order ~10-6 (i.e., similar orders of magnitude to seismic waves), it is challenging. A comparison of such forced oscillation setups will be presented to provide an overview of the various possibilities of design and implementation for future setups. In general, there is a lack of laboratory data and most of the published data are for sandstones. Currently, attenuation measurements are being carried out on carbonate and sandstone samples. We employ the Seismic Wave Attenuation Module (SWAM, Madonna & Tisato 2013) to measure seismic attenuation in these samples for different saturation degrees (90% and 100% water) and under three different confining pressures (5, 10 and 15MPa). Preliminary results from these investigations will be discussed. REFERENCES Madonna, C. & Tisato, N. 2013: A new seismic wave attenuation module to experimentally measure low-frequency attenuation in extensional mode. Geophysical Prospecting, doi: 10.1111/1365-2478.12015. Tisato, N. & Madonna, C. 2012: Attenuation at low seismic frequencies in partially saturated rocks: Measurements and description of a new apparatus. Journal of Applied Geophysics, 86, 44-53.

  5. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  6. FSO and radio link attenuation: meteorological models verified by experiment

    Science.gov (United States)

    Brazda, Vladimir; Fiser, Ondrej; Svoboda, Jaroslav

    2011-09-01

    Institute of Atmospheric Physics of Czech Academy measures atmospheric attenuation on 60 m experimental FSO link on 830 and 1550 nm for more than three years. Visibility sensors and two 3D sonic anemometers on both transmitting and receiving site, rain gauge and many sensors enabling the refractivity index computation are spaced along the optical link. Meteorological visibility, wind turbulent energy, sonic temperature, structure index and rain rate are correlated with measured attenuation. FSO link attenuation dependence on the above mentioned parameters is analyzed. The paper shows also basic statistical behavior of the long-term FSO signal level and also the simulation of hybrid link techniques.

  7. PID Gain Tuning for Disturbance Attenuation FRIT Method

    Science.gov (United States)

    Masuda, Shiro

    This review paper shows a PID gains tuning method from one-shot experimental data generated by test signal added at input signal in an off-line manner, so that the output signal could follow the prescribed reference model output. We call the method a “disturbance attenuation FRIT method” because the test signal added at input signal is a benchmark signal evaluating disturbance attenuation property. The experimental result for helicopter attitude control model is demonstrated to show the effectiveness of the disturbance attenuation FRIT method.

  8. Esmolol vs. nitroglycerin: attenuating hemodynamic response to laryngoscopy and intubation

    Directory of Open Access Journals (Sweden)

    Cassie Held

    2016-01-01

    Full Text Available Hemodynamic response to laryngoscopy and intubation is a common occurrence with the potential for harmful effects. Many drugs have been utilized throughout the years to attenuate this response with mixed results. This review compares the efficacy of two drugs, esmolol and nitroglycerin, in attenuating hemodynamic response to laryngoscopy and intubation. A systematic review was performed compiling all previous studies detailing the efficacy of esmolol in comparison to nitroglycerin for this purpose. Esmolol was found to consistently attenuate hemodynamic responses of blood pressure and heart rate with greater efficacy than nitroglycerin, and is thus recommended over nitroglycerin for use in this role.

  9. MNAtoolbox: A Monitored Natural Attenuation Site Screening Program

    Energy Technology Data Exchange (ETDEWEB)

    Borns, David J.; Brady, Patrick V.; Brady, Warren D.; Krupka, Kenneth M.; Spalding, Brian P.; Waters, Robert D.; Zhang, Pengchu

    1999-07-12

    Screening of sites for the potential application and reliance upon monitored natural attenuation (MNA) can be done using MNAtoolbox, a web-based tool for estimating extent of biodegradation, chemical transformation, and dilution. MNAtoolbox uses site-specific input data, where available (default parameters are taken from the literature), to roughly quantify the nature and extent of attenuation at a particular site. Use of MNAtoolbox provides 3 important elements of site evaluation: (1) Identifies likely attenuation pathways, (2) Clearly identifies sites where MNA is inappropriate, and (3) Evaluates data requirements for subsequent reliance on MNA as a sole or partial corrective action.

  10. Improving EMI Attenuation in Frequency Modulated Power Converters

    OpenAIRE

    Stepins, D.

    2009-01-01

    The effect of frequency modulation on a power switching converter electromagnetic interference (EMI) attenuation is examined in this paper. A method known as “modified sawtooth” is applied for EMI attenuation in a boost converter and it is optimized in such a way to reduce EMI more effectively. The method is also verified experimentally by the use of a low power boost converter controlled via an arbitrary waveform generator. EMI attenuation up to 15 dB is achieved after using modified sawtoot...

  11. Ultrasonic attenuation measurements determine onset, degree, and completion of recrystallization

    Science.gov (United States)

    Generazio, E. R.

    1988-01-01

    Ultrasonic attenuation was measured for cold worked Nickel 200 samples annealed at increasing temperatures. Localized dislocation density variations, crystalline order and volume percent of recrystallized phase were determined over the anneal temperature range using transmission electron microscopy, X-ray diffraction, and metallurgy. The exponent of the frequency dependence of the attenuation was found to be a key variable relating ultrasonic attenuation to the thermal kinetics of the recrystallization process. Identification of this key variable allows for the ultrasonic determination of onset, degree, and completion of recrystallization.

  12. Dispersion effects on infrared spectra in attenuated total reflection

    Science.gov (United States)

    Belali, Rabah; Vigoureux, Jean-Marie; Morvan, Joseph

    1995-12-01

    A potential problem with the attenuated total reflection that is used to measure infrared spectra is described. The problem is the possibility that the anomalous dispersion associated with an infrared absorption band may cause the experimental configuration to move from the attenuated total reflection regime to the specular reflection regime, with consequent distortion of the apparent absorption bands and consequent error in the interpretation of the bands if the problem is not recognized. Key infrared spectra, attenuated total reflection, specular reflection, polyethylene terephtalate. Copyright (c) 1995 Optical Society of America

  13. Photon attenuation properties of some thorium, uranium and plutonium compounds

    International Nuclear Information System (INIS)

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  14. Dimethyl Ether Sector Develops Rapidly

    Institute of Scientific and Technical Information of China (English)

    Zong Yangong

    2007-01-01

    @@ Rapid capacity expansion Dimethyl ether production in China has developed rapidly in recent years. The total capacity of dimethyl ether in China was only 31.8 thousand t/a in 2002, the output was around 20 thousand tons and the operating rate was 63%. The number of producers increased to over 30 in 2006.

  15. Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation.

    Science.gov (United States)

    Reisenauer, Chris J; Bhatt, Dhaval P; Mitteness, Dane J; Slanczka, Evan R; Gienger, Heidi M; Watt, John A; Rosenberger, Thad A

    2011-04-01

    Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6 g/kg by oral gavage. In parallel experiments, free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 h. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 h. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive glial fibrillary acidic protein-positive astrocytes and activated CD11b-positive microglia by 40-50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of choline acetyltransferase (ChAT)-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model. PMID:21272004

  16. p85α promotes nucleolin transcription and subsequently enhances EGFR mRNA stability and EGF-induced malignant cellular transformation.

    Science.gov (United States)

    Xie, Qipeng; Guo, Xirui; Gu, Jiayan; Zhang, Liping; Jin, Honglei; Huang, Haishan; Li, Jingxia; Huang, Chuanshu

    2016-03-29

    p85α is a regulatory subunit of phosphatidylinositol 3-kinase (PI3K) that is a key lipid enzyme for generating phosphatidylinositol 3, 4, 5-trisphosphate, and subsequently activates signaling that ultimately regulates cell cycle progression, cell growth, cytoskeletal changes, and cell migration. In addition to form a complex with the p110 catalytic subunit, p85α also exists as a monomeric form due to that there is a greater abundance of p85α than p110 in many cell types. Our previous studies have demonstrated that monomeric p85α exerts a pro-apoptotic role in UV response through induction of TNF-α gene expression in PI3K-independent manner. In current studies, we identified a novel biological function of p85α as a positive regulator of epidermal growth factor receptor (EGFR) expression and cell malignant transformation via nucleolin-dependent mechanism. Our results showed that p85α was crucial for EGFR and nucleolin expression and subsequently resulted in an increase of malignant cellular transformation by using both specific knockdown and deletion of p85α in its normal expressed cells. Mechanistic studies revealed that p85α upregulated EGFR protein expression mainly through stabilizing its mRNA, whereas nucleolin (NCL) was able to bind to egfr mRNA and increase its mRNA stability. Consistently, overexpression of NCL in p85α-/- cells restored EGFR mRNA stabilization, protein expression and cell malignant transformation. Moreover, we discovered that p85α upregulated NCL gene transcription via enhancing C-Jun activation. Collectively, our studies demonstrate a novel function of p85α as a positive regulator of EGFR mRNA stability and cell malignant transformation, providing a significant insight into the understanding of biomedical nature of p85α protein in mammalian cells and further supporting that p85α might be a potential target for cancer prevention and therapy. PMID:26918608

  17. p85α promotes nucleolin transcription and subsequently enhances EGFR mRNA stability and EGF-induced malignant cellular transformation

    Science.gov (United States)

    Gu, Jiayan; Zhang, Liping; Jin, Honglei; Huang, Haishan; Li, Jingxia; Huang, Chuanshu

    2016-01-01

    p85α is a regulatory subunit of phosphatidylinositol 3-kinase (PI3K) that is a key lipid enzyme for generating phosphatidylinositol 3, 4, 5-trisphosphate, and subsequently activates signaling that ultimately regulates cell cycle progression, cell growth, cytoskeletal changes, and cell migration. In addition to form a complex with the p110 catalytic subunit, p85α also exists as a monomeric form due to that there is a greater abundance of p85α than p110 in many cell types. Our previous studies have demonstrated that monomeric p85α exerts a pro-apoptotic role in UV response through induction of TNF-α gene expression in PI3K-independent manner. In current studies, we identified a novel biological function of p85α as a positive regulator of epidermal growth factor receptor (EGFR) expression and cell malignant transformation via nucleolin-dependent mechanism. Our results showed that p85α was crucial for EGFR and nucleolin expression and subsequently resulted in an increase of malignant cellular transformation by using both specific knockdown and deletion of p85α in its normal expressed cells. Mechanistic studies revealed that p85α upregulated EGFR protein expression mainly through stabilizing its mRNA, whereas nucleolin (NCL) was able to bind to egfr mRNA and increase its mRNA stability. Consistently, overexpression of NCL in p85α−/− cells restored EGFR mRNA stabilization, protein expression and cell malignant transformation. Moreover, we discovered that p85α upregulated NCL gene transcription via enhancing C-Jun activation. Collectively, our studies demonstrate a novel function of p85α as a positive regulator of EGFR mRNA stability and cell malignant transformation, providing a significant insight into the understanding of biomedical nature of p85α protein in mammalian cells and further supporting that p85α might be a potential target for cancer prevention and therapy. PMID:26918608

  18. Magnitude corrections for attenuation in the upper mantle

    International Nuclear Information System (INIS)

    Since 1969, a consistent discrepancy in seismic magnitudes of nuclear detonations at NTS compared with magnitudes of detonations elsewhere in the world has been observed. This discrepancy can be explained in terms of a relatively high seismic attenuation for compressional waves in the upper mantle beneath the NTS and in certain other locations. A correction has been developed for this attenuation based on a relationship between the velocity of compressional waves at the top of the earth's mantle (just beneath the Mohorovicic discontinuity) and the seismic attenuation further down in the upper mantle. Our new definition of body-wave magnitude includes corrections for attenuation in the upper mantle at both ends of the teleseismic body-wave path. These corrections bring the NTS oservations into line with measurements of foreign events, and enable one to make more reliable estimates of yields of underground nuclear explosions, wherever the explosion occurs

  19. Earth/Mars Landing Impact Attenuation Using Foam Project

    Data.gov (United States)

    National Aeronautics and Space Administration — On a previous ICA, a test correlated excel based software tool was developed using the innovative Stress?Energy method to better model impact attenuation using...

  20. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Science.gov (United States)

    Jalali, Majid; Mohammadi, Ali

    2008-05-01

    The compounds Na 2B 4O 7, H 3BO 3, CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  1. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    International Nuclear Information System (INIS)

    The compounds Na2B4O7, H3BO3, CdCl2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H3BO3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds

  2. Dose reduction using a dynamic, piecewise-linear attenuator

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Fleischmann, Dominik [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-02-15

    Purpose: The authors recently proposed a dynamic, prepatient x-ray attenuator capable of producing a piecewise-linear attenuation profile customized to each patient and viewing angle. This attenuator was intended to reduce scatter-to-primary ratio (SPR), dynamic range, and dose by redistributing flux. In this work the authors tested the ability of the attenuator to reduce dose and SPR in simulations. Methods: The authors selected four clinical applications, including routine full field-of-view scans of the thorax and abdomen, and targeted reconstruction tasks for an abdominal aortic aneurysm and the pancreas. Raw data were estimated by forward projection of the image volume datasets. The dynamic attenuator was controlled to reduce dose while maintaining peak variance by solving a convex optimization problem, assuminga priori knowledge of the patient anatomy. In targeted reconstruction tasks, the noise in specific regions was given increased weighting. A system with a standard attenuator (or “bowtie filter”) was used as a reference, and used either convex optimized tube current modulation (TCM) or a standard TCM heuristic. The noise of the scan was determined analytically while the dose was estimated using Monte Carlo simulations. Scatter was also estimated using Monte Carlo simulations. The sensitivity of the dynamic attenuator to patient centering was also examined by shifting the abdomen in 2 cm intervals. Results: Compared to a reference system with optimized TCM, use of the dynamic attenuator reduced dose by about 30% in routine scans and 50% in targeted scans. Compared to the TCM heuristics which are typically used withouta priori knowledge, the dose reduction is about 50% for routine scans. The dynamic attenuator gives the ability to redistribute noise and variance and produces more uniform noise profiles than systems with a conventional bowtie filter. The SPR was also modestly reduced by 10% in the thorax and 24% in the abdomen. Imaging with the dynamic

  3. How Rapid is Rapid Prototyping? Analysis of ESPADON Programme Results

    Directory of Open Access Journals (Sweden)

    Ian D. Alston

    2003-05-01

    Full Text Available New methodologies, engineering processes, and support environments are beginning to emerge for embedded signal processing systems. The main objectives are to enable defence industry to field state-of-the-art products in less time and with lower costs, including retrofits and upgrades, based predominately on commercial off the shelf (COTS components and the model-year concept. One of the cornerstones of the new methodologies is the concept of rapid prototyping. This is the ability to rapidly and seamlessly move from functional design to the architectural design to the implementation, through automatic code generation tools, onto real-time COTS test beds. In this paper, we try to quantify the term “rapid” and provide results, the metrics, from two independent benchmarks, a radar and sonar beamforming application subset. The metrics show that the rapid prototyping process may be sixteen times faster than a conventional process.

  4. Characterizing X-ray Attenuation of Containerized Cargo

    Energy Technology Data Exchange (ETDEWEB)

    Birrer, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divin, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wang, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-02

    X-ray inspection systems can be used to detect radiological and nuclear threats in imported cargo. In order to better understand performance of these systems, the attenuation characteristics of imported cargo need to be determined. This project focused on developing image processing algorithms for segmenting cargo and using x-ray attenuation to quantify equivalent steel thickness to determine cargo density. These algorithms were applied to over 450 cargo radiographs. The results are summarized in this report.

  5. Attenuation of 3CM Microwaves Due to Artificial Rain

    Directory of Open Access Journals (Sweden)

    J. K. Singh

    1966-04-01

    Full Text Available Observations to study the variation of attenuation of 3cm waves due to falling of water or artificial rain are confined to the high rates of precipitation and short distance between the transmitter and receiver, due to low power of the microwave generator. A comparison of these observations and those recorded by others shows that the attenuation increases nonlinearly with the intensity of artificial rainfall which is generally assumed to be linear for the observations at lower rates of precipitation.

  6. An analysis of seismic attenuation in random porous media

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The attenuation of seismic wave in rocks has been one of the interesting research topics, but till now no poroelasticity models can thoroughly explain the strong attenuation of wave in rocks. In this paper, a random porous medium model is designed to study the law of wave propagation in complex rocks based on the theory of Biot poroelasticity and the general theory of stochastic process. This model sets the density of grain, porosity, permeability and modulus of frame as random parameters in space, and only one fluid infiltrates in rocks for the sake of better simulation effect in line with real rocks in earth strata. Numerical simulations are implemented. Two different inverse quality factors of fast P-wave are obtained by different methods to assess attenuation through records of virtual detectors in wave field (One is amplitude decay method in time domain and the other is spectral ratio method in frequency domain). Comparing the attenuation results of random porous medium with those of homogeneous porous medium, we conclude that the attenuation of seismic wave of homogeneous porous medium is far weaker than that of random porous medium. In random porous media, the higher heterogeneous level is, the stronger the attenuation becomes, and when heterogeneity σ = 0.15 in simulation, the attenuation result is consistent with that by actual observation. Since the central frequency (50 Hz) of source in numerical simulation is in earthquake band, the numerical results prove that heterogeneous porous structure is one of the important factors causing strong attenuation in real stratum at intermediate and low frequency.

  7. Rationalizing the development of live attenuated virus vaccines

    OpenAIRE

    Lauring, Adam S.; Jones, Jeremy O.; Andino, Raul

    2010-01-01

    Since the first demonstration of the protective effects of vaccinia inoculation, vaccination has been one of the medicine’s greatest successes. The design of vaccines against viral disease has evolved considerably over the last 50 years. Classically attenuated viruses, those created by passaging a virus in cultured cells, have proven to be an effective means for preventing many viral diseases, including smallpox, polio, measles, mumps, and yellow fever. However, empiric attenuation is not a r...

  8. Kramers-Kronig relationship between ultrasonic attenuation and phase velocity

    Science.gov (United States)

    Odonnell, M.; Jaynes, E. T.; Miller, J. G.

    1981-01-01

    Kramers-Kronig relations linking the attenuation and dispersion are presented for a linear acoustic system. These expressions are used as a starting point to derive approximate, nearly local expressions relating the ultrasonic attenuation at a specific frequency to the local frequency derivative of the phase velocity (i.e., dispersion). The validity of these approximate relationships is demonstrated in several acoustic systems exhibiting substantially different physical properties.

  9. Proteomic analysis of pathogenic and attenuated alcelaphine herpesvirus 1

    OpenAIRE

    Dry, Inga; Haig, David M; Inglis, Neil F.; Imrie, Lisa; Stewart, James P; Russell, George C.

    2008-01-01

    The gammaherpesvirus alcelaphine herpesvirus 1 (AlHV-1) causes malignant catarrhal fever in susceptible ungulates but infects its natural host, wildebeest, without obvious clinical signs. In tissue culture, AlHV-1 is initially predominantly cell associated and virulent but on extended culture becomes cell-free and attenuated. We wanted to determine what changes in protein composition had taken place during the transition from virulent to attenuated virus in culture. Purified virus preparation...

  10. Esmolol vs. nitroglycerin: attenuating hemodynamic response to laryngoscopy and intubation

    OpenAIRE

    Cassie Held

    2016-01-01

    Hemodynamic response to laryngoscopy and intubation is a common occurrence with the potential for harmful effects. Many drugs have been utilized throughout the years to attenuate this response with mixed results. This review compares the efficacy of two drugs, esmolol and nitroglycerin, in attenuating hemodynamic response to laryngoscopy and intubation. A systematic review was performed compiling all previous studies detailing the efficacy of esmolol in comparison to nitroglycerin for this pu...

  11. Low energy gamma ray attenuation in multiphase water

    Science.gov (United States)

    Singh, Jag J.; Sprinkle, Danny R.; Eftekhari, Abe

    1990-01-01

    A gauging system is proposed to enable monitoring of slush density, solid-liquid interface, and slush level as well as its flow rate. It is based on the principle that the electromagnetic radiation mass attenuation coefficient of a multiphase chemical compound is constant for all relative phase concentrations. Results showing the essential constancy of mass attenuation coefficients for single-phase water vapor, liquid water, ice, and multiphase mixtures of water/ice are described.

  12. Nuclear equipment to determine soil and water mass attenuation coefficients

    International Nuclear Information System (INIS)

    The feasibility of substituting the monochannel gamma spectrometer, traditionally used in the gamma ray attenuation technique, for a less sophisticated and less expensive system of integral counting is studied. The proposed system can be operated by a non-specialized person. Three detection systems were used in the determination of the mass attenuation coefficients for different types of soil and for water. (M.A.C.)

  13. Ultrasound attenuation dependence on air compression or expansion processes

    OpenAIRE

    Jakevicius, L.; Demcenko, A.; Mardosaite, R.

    2010-01-01

    In this work variation of ultrasonic attenuation coefficient is analyzed in terms of air compression or expansion processes. In closed spaces changing air volume, the ultrasound attenuation coefficient depends on thermodynamic processes which occur during the air volume change. Two limiting cases are possible: 1) if the change of air volume is very slow or intensive heat exchange occurs between the system and surrounding environments, so the system stays in a thermodynamic equilibrium; theref...

  14. Radar Signal Attenuation due to Finite Radome Thickness

    OpenAIRE

    Képeši, Viktor; Labun, Ján

    2015-01-01

    Radar antennas deployed in real use usually include a protective dome, which shields them from potentially harmful weather conditions. The protective dome is typically constructed from a plastic material, which can affect the radar signal. The presented paper deals with signal attenuation caused by radar’s dome. It provides results of a computer simulation concerning this attenuation based on different thickness of the material used for radome construction. The presented results give insight ...

  15. Medical image of the week: expiratory imaging accentuates mosaic attenuation

    OpenAIRE

    Arteaga VA; Knox KS

    2013-01-01

    A 66 year old female presented with cough, fever and marked shortness of breath. Infectious work up was found to be negative. An inspiratory high resolution thoracic CT (HRCT) image (A) shows faint groundglass and mosaic lung attenuation with subtle centrilobular ill-defined nodules. However, an image obtained on expiration (B) shows more obvious mosaic attenuation which suggesting air-trapping. Due to progressive dyspnea, a lung biopsy was performed and revealed a bronchiolocentric cellu...

  16. Low-Cost Electronic Microwave Calibration for Rapid On-Line Moisture Sensing of Seedcotton

    OpenAIRE

    Viera, Joseph A.; Pelletier, Mathew G.

    2010-01-01

    In order to improve rapid on-line moisture sensing of seedcotton in cotton gins, a means by which to establish a reliable low-cost wide-band electronic calibration is critically needed. This calibration is needed to center the circuit due to changes in the internal signal delays and attenuation drift caused by temperature changes in the various system components and circuit elements. This research examines a hardware technique for use in conjunction with microwave reflective sensing probes ha...

  17. DNA-launched live-attenuated vaccines for biodefense applications.

    Science.gov (United States)

    Pushko, Peter; Lukashevich, Igor S; Weaver, Scott C; Tretyakova, Irina

    2016-09-01

    A novel vaccine platform uses DNA immunization to launch live-attenuated virus vaccines in vivo. This technology has been applied for vaccine development against positive-strand RNA viruses with global public health impact including alphaviruses and flaviviruses. The DNA-launched vaccine represents the recombinant plasmid that encodes the full-length genomic RNA of live-attenuated virus downstream from a eukaryotic promoter. When administered in vivo, the genomic RNA of live-attenuated virus is transcribed. The RNA initiates limited replication of a genetically defined, live-attenuated vaccine virus in the tissues of the vaccine recipient, thereby inducing a protective immune response. This platform combines the strengths of reverse genetics, DNA immunization and the advantages of live-attenuated vaccines, resulting in a reduced chance of genetic reversions, increased safety, and improved immunization. With this vaccine technology, the field of DNA vaccines is expanded from those that express subunit antigens to include a novel type of DNA vaccines that launch live-attenuated viruses. PMID:27055100

  18. Attenuation Coefficient Estimation of the Healthy Human Thyroid In Vivo

    Science.gov (United States)

    Rouyer, J.; Cueva, T.; Portal, A.; Yamamoto, T.; Lavarello, R.

    Previous studies have demonstrated that attenuation coefficients can be useful towards characterizing thyroid tissues. In this work, ultrasonic attenuation coefficients were estimated from healthy human thyroids in vivo using a clinical scanner. The selected subjects were five young, healthy volunteers (age: 26 ± 6 years old, gender: three females, two males) with no reported history of thyroid diseases, no palpable thyroid nodules, no smoking habits, and body mass index less than 30 kg/m2. Echographic examinations were conducted by a trained sonographer using a SonixTouch system (Ultrasonix Medical Corporation, Richmond, BC) equipped with an L14-5 linear transducer array (nominal center frequency of 10 MHz, transducer footprint of 3.8 cm). Radiofrequency data corresponding to the collected echographic images in both transverse and longitudinal views were digitized at a sampling rate of 40 MHz and processed with Matlab codes (MathWorks, Natick, MA) to estimate attenuation coefficients using the spectral log difference method. The estimation was performed using an analysis bandwidth spanning from 4.0 to 9.0 MHz. The average value of the estimated ultrasonic attenuation coefficients was equal to 1.34 ± 0.15 dB/(cm.MHz). The standard deviation of the estimated average attenuation coefficient across different volunteers suggests a non-negligible inter-subject variability in the ultrasonic attenuation coefficient of the human thyroid.

  19. Novel point mutations attenuate autotaxin activity

    Directory of Open Access Journals (Sweden)

    Stracke Mary L

    2009-02-01

    Full Text Available Abstract Background The secreted enzyme autotaxin (ATX stimulates tumor cell migration, tumorigenesis, angiogenesis, and metastasis. ATX hydrolyzes nucleotides, but its hydrolysis of lysophospholipids to produce lysophosphatidic acid (LPA accounts for its biological activities. ATX has been identified only as a constitutively active enzyme, and regulation of its activity is largely unexplored. In spite of its presence in plasma along with abundant putative substrate LPC, the product LPA is found in plasma at unexpectedly low concentrations. It is plausible that the LPA-producing activity of ATX is regulated by its expression and by access to substrate(s. For this reason studying the interaction of enzyme with substrate is paramount to understanding the regulation of LPA production. Results In this study we determine ATX hydrolytic activities toward several artificial and natural substrates. Two novel point mutations near the enzyme active site (H226Q and H434Q confer attenuated activity toward all substrates tested. The Vmax for LPC compounds depends upon chain length and saturation; but this order does not differ among wild type and mutants. However the mutant forms show disproportionately low activity toward two artificial substrates, pNpTMP and FS-3. The mutant forms did not significantly stimulate migration responses at concentrations that produced a maximum response for WT-ATX, but this defect could be rescued by inclusion of exogenous LPC. Conclusion H226Q-ATX and H434Q-ATX are the first point mutations of ATX/NPP2 demonstrated to differentially impair substrate hydrolysis, with hydrolysis of artificial substrates being disproportionately lower than that of LPC. This implies that H226 and H434 are important for substrate interaction. Assays that rely on hydrolyses of artificial substrates (FS-3 and pNpTMP, or that rely on hydrolysis of cell-derived substrate, might fail to detect certain mutated forms of ATX that are nonetheless capable of

  20. Synonymous Deoptimization of Foot-and-Mouth Disease Virus Causes Attenuation In Vivo while Inducing a Strong Neutralizing Antibody Response

    Science.gov (United States)

    Diaz-San Segundo, Fayna; Medina, Gisselle N.; Ramirez-Medina, Elizabeth; Velazquez-Salinas, Lauro; Koster, Marla; Grubman, Marvin J.

    2015-01-01

    ABSTRACT Codon bias deoptimization has been previously used to successfully attenuate human pathogens, including poliovirus, respiratory syncytial virus, and influenza virus. We have applied a similar technology to deoptimize the capsid-coding region (P1) of foot-and-mouth disease virus (FMDV). Despite the introduction of 489 nucleotide changes (19%), synonymous deoptimization of the P1 region rendered a viable FMDV progeny. The resulting strain was stable and reached cell culture titers similar to those obtained for wild-type (WT) virus, but at reduced specific infectivity. Studies in mice showed that 100% of animals inoculated with the FMDV A12 P1 deoptimized mutant (A12-P1 deopt) survived, even when the animals were infected at doses 100 times higher than the dose required to cause death by WT virus. All mice inoculated with the A12-P1 deopt mutant developed a strong antibody response and were protected against subsequent lethal challenge with WT virus at 21 days postinoculation. Remarkably, the vaccine safety margin was at least 1,000-fold higher for A12-P1 deopt than for WT virus. Similar patterns of attenuation were observed in swine, in which animals inoculated with A12-P1 deopt virus did not develop clinical disease until doses reached 1,000 to 10,000 times the dose required to cause severe disease in 2 days with WT A12. Consistently, high levels of antibody titers were induced, even at the lowest dose tested. These results highlight the potential use of synonymous codon pair deoptimization as a strategy to safely attenuate FMDV and further develop live attenuated vaccine candidates to control such a feared livestock disease. IMPORTANCE Foot-and-mouth disease (FMD) is one of the most feared viral diseases that can affect livestock. Although this disease appeared to be contained in developed nations by the end of the last century, recent outbreaks in Europe, Japan, Taiwan, South Korea, etc., have demonstrated that infection can spread rapidly, causing

  1. Rapid Multiplex Microbial Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC, in collaboration with Lucigen, proposes a rapid nucleic acid-based detector for spaceflight water systems to enable simultaneous quantification of multiple...

  2. A Rapid Coliform Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC, in collaboration with Lucigen, proposes a rapid genetic detector for spaceflight water systems to enable real-time detection of E-coli with minimal...

  3. Rapid deployment intrusion detection system

    International Nuclear Information System (INIS)

    A rapidly deployable security system is one that provides intrusion detection, assessment, communications, and annunciation capabilities; is easy to install and configure; can be rapidly deployed, and is reusable. A rapidly deployable intrusion detection system (RADIDS) has many potential applications within the DOE Complex: back-up protection for failed zones in a perimeter intrusion detection and assessment system, intrusion detection and assessment capabilities in temporary locations, protection of assets during Complex reconfiguration, and protection in hazardous locations, protection of assets during Complex reconfiguration, and protection in hazardous locations. Many DOE user-need documents have indicated an interest in a rapidly deployable intrusion detection system. The purpose of the RADIDS project is to design, develop, and implement such a system. 2 figs

  4. Patient position alters attenuation effects in multipinhole cardiac SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Timmins, Rachel; Ruddy, Terrence D.; Wells, R. Glenn, E-mail: gwells@ottawaheart.ca [Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7 (Canada)

    2015-03-15

    Purpose: Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Methods: Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Results: Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of <1.5 for the water phantom but up to 4.2 in the anthropomorphic phantom. Changes were larger for axial than for transverse translations. These results were supported by SPS changes of up to six seen in the physical anthropomorphic phantom for axial translations. Defect width was also seen to significantly increase. The

  5. Orexigenic hormone ghrelin attenuates local and remote organ injury after intestinal ischemia-reperfusion.

    Directory of Open Access Journals (Sweden)

    Rongqian Wu

    Full Text Available BACKGROUND: Gut ischemia/reperfusion (I/R injury is a serious condition in intensive care patients. Activation of immune cells adjacent to the huge endothelial cell surface area of the intestinal microvasculature produces initially local and then systemic inflammatory responses. Stimulation of the vagus nerve can rapidly attenuate systemic inflammatory responses through inhibiting the activation of macrophages and endothelial cells. Ghrelin, a novel orexigenic hormone, is produced predominately in the gastrointestinal system. Ghrelin receptors are expressed at a high density in the dorsal vagal complex of the brain stem. In this study, we investigated the regulation of the cholinergic anti-inflammatory pathway by the novel gastrointestinal hormone, ghrelin, after gut I/R. METHODS AND FINDINGS: Gut ischemia was induced by placing a microvascular clip across the superior mesenteric artery for 90 min in male adult rats. Our results showed that ghrelin levels were significantly reduced after gut I/R and that ghrelin administration inhibited pro-inflammatory cytokine release, reduced neutrophil infiltration, ameliorated intestinal barrier dysfunction, attenuated organ injury, and improved survival after gut I/R. Administration of a specific ghrelin receptor antagonist worsened gut I/R-induced organ injury and mortality. To determine whether ghrelin's beneficial effects after gut I/R require the intact vagus nerve, vagotomy was performed in sham and gut I/R animals immediately prior to the induction of gut ischemia. Our result showed that vagotomy completely eliminated ghrelin's beneficial effect after gut I/R. To further confirm that ghrelin's beneficial effects after gut I/R are mediated through the central nervous system, intracerebroventricular administration of ghrelin was performed at the beginning of reperfusion after 90-min gut ischemia. Our result showed that intracerebroventricular injection of ghrelin also protected the rats from gut I

  6. The first EGF domain of coagulation factor IX attenuates cell adhesion and induces apoptosis.

    Science.gov (United States)

    Ishikawa, Tomomi; Kitano, Hisataka; Mamiya, Atsushi; Kokubun, Shinichiro; Hidai, Chiaki

    2016-07-01

    Coagulation factor IX (FIX) is an essential plasma protein for blood coagulation. The first epidermal growth factor (EGF) motif of FIX (EGF-F9) has been reported to attenuate cell adhesion to the extracellular matrix (ECM). The purpose of the present study was to determine the effects of this motif on cell adhesion and apoptosis. Treatment with a recombinant EGF-F9 attenuated cell adhesion to the ECM within 10 min. De-adhesion assays with native FIX recombinant FIX deletion mutant proteins suggested that the de-adhesion activity of EGF-F9 requires the same process of FIX activation as that which occurs for coagulation activity. The recombinant EGF-F9 increased lactate dehydrogenase (LDH) activity release into the medium and increased the number of cells stained with annexin V and activated caspase-3, by 8.8- and 2.7-fold respectively, indicating that EGF-F9 induced apoptosis. Activated caspase-3 increased very rapidly after only 5 min of administration of recombinant EGF-F9. Treatment with EGF-F9 increased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK), but not that of phosphorylated MAPK 44/42 or c-Jun N-terminal kinase (JNK). Inhibitors of caspase-3 suppressed the release of LDH. Caspase-3 inhibitors also suppressed the attenuation of cell adhesion and phosphorylation of p38 MAPK by EGF-F9. Our data indicated that EGF-F9 activated signals for apoptosis and induced de-adhesion in a caspase-3 dependent manner. PMID:27129300

  7. Economical Investigation of Rapid Prototyping

    OpenAIRE

    Péter Ficzere; Lajos Borbás; Ádám Török

    2013-01-01

    Usage of rapid prototyping gain developers, designers and engineers more time and consume less money and save more resources. In this article authors investigated the economic possibilities of rapid prototyping. In concurrent engineering, different tasks are tackled at the same time, and not necessarily in the usual order. Concurrent engineering is a method by which several teams within an organization work simultaneously to develop new products and allows more flexible approach. The concurre...

  8. Dilepton distributions at backward rapidities

    CERN Document Server

    Betemps, M A; De Oliveira, E G

    2006-01-01

    The dilepton production at backward rapidities in $pAu$ and $pp$ collisions at RHIC and LHC energies is investigated in the dipole approach. The results are shown through the nuclear modification ratio $R_{pA}$ considering the transverse momentum and rapidity spectra. The dilepton modification ratio presents interesting behavior at the backward rapidities once compared with the already known forward one, since it is related with large $x$ kinematical region that is being probed. The nuclear modification ratio rapidity spectrum in the dilepton production is strongly dependent on the Bjorken $x$ behavior of the nuclear structure function ratio $R_{F_{2}}=F_{2}^{A}/F_{2}^{p}$. The $R_{pA}$ transverse momentum dependence at backward rapidities is modified due to the large $x$ nuclear effects: at RHIC energies, for instance, the ratio $R_{pA}$ is reduced as $p_T$ increases, presenting oppositive behavior once compared with the forward one. It implies the dilepton production at backward rapidities should carry info...

  9. Characteristics of coda wave attenuation in Yunnan area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The characteristic of seismic coda wave attenuation in Yunnan area in 7 frequency-bands range from 1 Hz to 20 Hz was estimated by using the local earthquake's waveform data recorded from 22 Yunnan digital seismic stations.Coda attenuation Q-c1 of each station was firstly calculated by single scattering method. Then, mean free path Le and seismic albedo Bo of each station were calculated, and scattering attenuation Q-1s and intrinsic attenuation Q-1i were separated from total attenuation Q-1t by multiple lapse time window analysis based on the multiple scattering model in uniform random isotropic scattering medium. The attenuating characteristics in Yunnan show that most value of Le are in 10~30 km, with maximal within 2~6 Hz;Bo are about 0.5 at 1~2 Hz, but less than 0.5at other frequency-bands, which means Q-1i is comparable with Q-1s at 1~2 Hz, and after 1~2 Hz, Q-1i is greater than Q-1s and dominates the attenuation process. Q-1c is close to Q-1i at other frequency bands except 1~2 Hz.Results show that Q-1 especially Qs-1 varies spatially, Q-1 in eastern Yunnan zone is a bit higher than in northwestern Yunnan zone;northwestern Yunnan zone higher than southwestern Yunnan zone. Comparing with other results in global, Qs-1 in Yunnan is lower than the global average value among these results, Q-1i is higher than the global average value, and Q-1t lies the middle among these results.

  10. Sequence-Specific Fidelity Alterations Associated with West Nile Virus Attenuation in Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Greta A Van Slyke

    2015-06-01

    Full Text Available High rates of error-prone replication result in the rapid accumulation of genetic diversity of RNA viruses. Recent studies suggest that mutation rates are selected for optimal viral fitness and that modest variations in replicase fidelity may be associated with viral attenuation. Arthropod-borne viruses (arboviruses are unique in their requirement for host cycling and may necessitate substantial genetic and phenotypic plasticity. In order to more thoroughly investigate the correlates, mechanisms and consequences of arbovirus fidelity, we selected fidelity variants of West Nile virus (WNV; Flaviviridae, Flavivirus utilizing selection in the presence of a mutagen. We identified two mutations in the WNV RNA-dependent RNA polymerase associated with increased fidelity, V793I and G806R, and a single mutation in the WNV methyltransferase, T248I, associated with decreased fidelity. Both deep-sequencing and in vitro biochemical assays confirmed strain-specific differences in both fidelity and mutational bias. WNV fidelity variants demonstrated host-specific alterations to replicative fitness in vitro, with modest attenuation in mosquito but not vertebrate cell culture. Experimental infections of colonized and field populations of Cx. quinquefaciatus demonstrated that WNV fidelity alterations are associated with a significantly impaired capacity to establish viable infections in mosquitoes. Taken together, these studies (i demonstrate the importance of allosteric interactions in regulating mutation rates, (ii establish that mutational spectra can be both sequence and strain-dependent, and (iii display the profound phenotypic consequences associated with altered replication complex function of flaviviruses.

  11. Guggulsterone attenuates cerulein-induced acute pancreatitis via inhibition of ERK and JNK activation.

    Science.gov (United States)

    Kim, Dong-Goo; Bae, Gi-Sang; Choi, Sun-Bok; Jo, Il-Joo; Shin, Joon-Yeon; Lee, Sung-Kon; Kim, Myoung-Jin; Kim, Min-Jun; Jeong, Hyun-Woo; Choi, Chang-Min; Seo, Seung-Hee; Choo, Gab-Chul; Seo, Sang-Wan; Song, Ho-Joon; Park, Sung-Joo

    2015-05-01

    Guggulsterone (GS), a plant steroid and a compound found at high levels in Commiphora myrrha, exhibits anti-inflammatory, anti-cancer, and cholesterol-lowering effects. However, the potential of GS to ameliorate acute pancreatitis (AP) is unknown. The aim of this study was to evaluate the effects of GS on cerulein-induced AP. AP was induced by intraperitoneally injecting supramaximal concentrations of the stable cholecystokinin analog cerulein (50 μg/kg) hourly for 6 h. In the GS-treated group, GS was administered intraperitoneally (10, 25, or 50mg/kg) 1 h before the first cerulein injection. Mice were sacrificed 6 h after the final cerulein injection. Blood samples were collected to measure serum lipase levels and evaluate cytokine production. The pancreas and lung were rapidly removed for morphologic and histological examinations, flow cytometry analysis, myeloperoxidase (MPO) assay, and real-time reverse transcription-polymerase chain reaction analysis. Pre-treatment with GS attenuated cerulein-induced histological damage, reduced pancreas weight/body weight ratio, decreased serum lipase levels, inhibited infiltrations of macrophages and neutrophils, and suppressed cytokine production. Additionally, GS treatment suppressed the activation of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) in the pancreas in cerulein-induced pancreatitis. In conclusion, our results suggest that GS attenuates AP via deactivation of ERK and JNK.

  12. In Vitro intestinal mucosal epithelial responses to wild-typeSalmonella Typhi and attenuated typhoid vaccines

    Directory of Open Access Journals (Sweden)

    Maria eFiorentino

    2013-02-01

    Full Text Available Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S. Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4h post-exposure. S. Typhi triggered the secretion of interleukin (IL-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

  13. Alfven waves and current relaxation: attenuation at high frequencies and large resistivity

    International Nuclear Information System (INIS)

    The dispersion relations of Alfven waves propagating in a resistive plasma are explored by assuming a finite relaxation time for the current density. It is shown that the proposed approach is consistent with the hydromagnetic approximation. An extension for the equation governing the space and time evolution of Alfven waves is provided. New results are found at high values of the wave frequency ω: for a small resistivity, the wavelength increases as the cube of the equilibrium magnetic field but decreases with the cube of ω; for a large resistivity, the wave attenuation does not depend on ω, saturating to a finite value which is fully determined by the relaxation time of the current density. A transition frequency, ωt, between two sharply distinct regimes of the perturbation is identified: for ω t, the disturbance propagates in the resistive plasma as an attenuated oscillation; for ω > ωt the wave ceases very rapidly to oscillate (in space), its amplitude saturating to a finite value. The results presented here may be relevant for investigations of some transient phenomena in plasma physics such as the reconnection of magnetic field lines.

  14. Remote sensing of the diffuse attenuation coefficient of ocean water. [coastal zone color scanner

    Science.gov (United States)

    Austin, R. W.

    1981-01-01

    A technique was devised which uses remotely sensed spectral radiances from the sea to assess the optical diffuse attenuation coefficient, K (lambda) of near-surface ocean water. With spectral image data from a sensor such as the coastal zone color scanner (CZCS) carried on NIMBUS-7, it is possible to rapidly compute the K (lambda) fields for large ocean areas and obtain K "images" which show synoptic, spatial distribution of this attenuation coefficient. The technique utilizes a relationship that has been determined between the value of K and the ratio of the upwelling radiances leaving the sea surface at two wavelengths. The relationship was developed to provide an algorithm for inferring K from the radiance images obtained by the CZCS, thus the wavelengths were selected from those used by this sensor, viz., 443, 520, 550 and 670 nm. The majority of the radiance arriving at the spacecraft is the result of scattering in the atmospheric and is unrelated to the radiance signal generated by the water. A necessary step in the processing of the data received by the sensor is, therefore, the effective removal of these atmospheric path radiance signals before the K algorithm is applied. Examples of the efficacy of these removal techniques are given together with examples of the spatial distributions of K in several ocean areas.

  15. Measurement of pulmonary edema in intact dogs by transthoracic gamma-ray attenuation

    International Nuclear Information System (INIS)

    Attenuation of the 122 keV gamma rays of cobalt-57 across the thorax of anesthetized dogs was evaluated as a method for following the time course of lung water changes in acute pulmonary edema induced by either increased microvascular permeability or increased microvascular hydrostatic pressure. The gamma rays traversed the thorax centered on the seventh rib laterally where the lung mass in the beam path was greatest. Calibration measurements in isolated lung lobes demonstrated the high sensitivity and inherent accuracy of the method over a wide range of lung water contents. In control dogs reproducibility averaged +-3%. Increased permeability edema led to large rapid increases in the transthoracic gamma ray attenuation (TGA), while increased pressure caused an immediate, modest increase in TGA (vascular congestion) followed by a slow further increase over 2 h. There was a fairly good correlation between the increase in extravascular lung water and the change in TGA. The method is simple, safe, and noninvasive and appears to be useful for following the time course of lung water accumulation in generalized lung edema in anesthetized animals

  16. Analysis of the association between periportal low attenuation, as seen on CT, after blunt abdominal trauma, and elevated central venous pressure

    International Nuclear Information System (INIS)

    To assess the causes of periportal low attenuation, as seen on CT, in patients with blunt abdominal trauma. From among 812 patients who underwent abdominal CT after blunt abdominal trauma, we retrospectively analysed the findings in 124 with evidence of periportal low attenuation. Among these, hepatic injury was noted in only 87. The presence or absence, and extent of hepatic injury, and of periportal low attenuation, as seen on CT, were carefully evaluated. In each case, the ratio of the transverse diameter of the inferior vena cava(IVC) to the aorta at the level of the right adrenal gland provided an indirect measurement of central venous pressure ; for control purposes, the ratio was also obtained in 21 non-traumatic patients with no abnormal abdominal CT findings. Of the 87 patients with hepatic injury, 46 showed no periportal low attenuation, and average value of the ratio between the IVC and aorta was 1.16±0.12, while the remaining 41 patients showed periportal low attenuation with a ratio of 1.51±0.21(p<0.05). In the 37 patients with periportal low attenuation but no evidence of concomitant hepatic injury, the average ratio was 1.52±0.25, while in 21 non-traumatic patients it was 1.15±0.16. For resuscitation, all patients had received 0.5-5.0 litre of IV fluid therapy before CT, and at the time of CT, were normotensive. Rapidly elevated central venous pressure following massive IV infusion therapy in patients with blunt abdominal trauma can be one of the causes of periportal low attenuation, as seen on CT

  17. Successful cross-protective efficacy induced by heat-adapted live attenuated nephropathogenic infectious bronchitis virus derived from a natural recombinant strain.

    Science.gov (United States)

    Lim, Tae-Hyun; Youn, Ha-Na; Yuk, Seong-Su; Kwon, Jung-Hoon; Hong, Woo-Tack; Gwon, Gyeong-Bin; Lee, Jung-Ah; Lee, Joong-Bok; Lee, Sang-Won; Song, Chang-Seon

    2015-12-16

    A natural recombinant nephropathogenic K40/09 strain of infectious bronchitis virus (IBV) was heat-adapted for possible future use as live attenuated vaccine. The K40/09 strain was selected during successive serial passages in specific-pathogen free (SPF) embryonated eggs at sub-optimal higher temperature (56°C). Unlike the parental strain, the attenuated strain, designated K40/09 HP50, was found to be safe in 1-day-old SPF chicks, which showed neither mortality nor signs of morbidity, and rarely induced ciliostasis or histological changes in the trachea and kidney after intraocular and fine-spray administration. K40/09 HP50 provided almost complete protection against two distinct subgroups of a nephropathogenic strain (KM91-like and QX-like subgroup) and elicited the production of high titers of neutralizing antibody (neutralization index of 3.6). We conclude that the K40/09 HP50 vaccine virus is rapidly attenuated by heat adaptation and exhibits the desired level of attenuation, immunogenicity, and protective efficacy required for a live attenuated vaccine. These results indicate that the K40/09 vaccine could be helpful for the reduction of economic losses caused by recently emergent nephropathogenic IBV infection in many countries.

  18. Stability of further-attenuated measles vaccines.

    Science.gov (United States)

    Mann, G F; Allison, L M; Lloyd, J S; Tam, P; Zuckerman, A J; Perkins, F T

    1983-01-01

    Accelerated stability tests on lyophilized measles vaccines show two distinct mechanisms of virus inactivation. A rapid initial loss of infectivity occurs only on exposure to temperatures above the ambient temperature. This loss is temperature related and may be attributable to the movement of residual moisture from the virus pellet into the void space of the vial. Subsequent inactivation of virus occurs at all temperatures as a first-order reaction that follows Arrhenius kinetics. Integration of values for these two components allows precise prediction of vaccine stability at any temperature. Analysis of the results obtained for greater than 30 vaccines shows that those which are stable for one week at 37 C have a predicted life of more than one year at 8 C. This simple test is now being applied to the identification of unstable products. The rate of this reaction is closely, if conservatively, matched by a time-temperature color indicator, which may be useful for monitoring vaccine quality. PMID:6879003

  19. Attenuation of trace organic compounds (TOrCs) inbioelectrochemical systems

    KAUST Repository

    Werner, Craig M.

    2015-04-01

    Microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are two types of microbial bioelectrochemical systems (BESs) that use microorganisms to convert chemical energy in wastewaters into useful energy products such as (bio)electricity (MFC) or hydrogen gas (MEC). These two systems were evaluated for their capacity to attenuate trace organic compounds (TOrCs), commonly found in municipal wastewater, under closed circuit (current generation) and open circuit (no current generation) conditions, using acetate as the carbon source. A biocide was used to evaluate attenuation in terms of biotransformation versus sorption. The difference in attenuation observed before and after addition of the biocide represented biotransformation, while attenuation after addition of a biocide primarily indicated sorption. Attenuation of TOrCs was similar in MFCs and MECs for eight different TOrCs, except for caffeine and trimethoprim where slightly higher attenuation was observed in MECs. Electric current generation did not enhance attenuation of the TOrCs except for caffeine, which showed slightly higher attenuation under closed circuit conditions in both MFCs and MECs. Substantial sorption of the TOrCs occurred to the biofilm-covered electrodes, but no consistent trend could be identified regarding the physico-chemical properties of the TOrCs tested and the extent of sorption. The octanol-water distribution coefficient at pH 7.4 (log DpH 7.4) appeared to be a reasonable predictor for sorption of some of the compounds (carbamazepine, atrazine, tris(2-chloroethyl) phosphate and diphenhydramine) but not for others (N,N-Diethyl-meta-toluamide). Atenolol also showed high levels of sorption despite being the most hydrophilic in the suite of compounds studied (log DpH 7.4=-1.99). Though BESs do not show any inherent advantages over conventional wastewater treatment, with respect to TOrC removal, overall removals in BESs are similar to that reported for conventional wastewater

  20. Optimized ultrasonic attenuation measures for non-homogeneous materials.

    Science.gov (United States)

    Genovés, V; Gosálbez, J; Carrión, A; Miralles, R; Payá, J

    2016-02-01

    In this paper the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous materials is addressed. To determine the attenuation accurately over a wide frequency range, it is necessary to have suitable excitation techniques. Three kinds of transmitted signals have been analysed, grouped according to their bandwidth: narrowband and broadband signals. The mathematical formulation has revealed the relation between the distribution of energy in their spectra and their immunity to noise. Sinusoidal and burst signals have higher signal-to-noise ratios (SNRs) but need many measurements to cover their frequency range. However, linear swept-frequency signals (chirp) improve the effective bandwidth covering a wide frequency range with a single measurement and equivalent accuracy, at the expense of a lower SNR. In the case of highly attenuating materials, it is proposed to use different configurations of chirp signals, enabling injecting more energy, and therefore, improving the sensitivity of the technique without a high time cost. Thus, if the attenuation of the material and the sensitivity of the measuring equipment allows the use of broadband signals, the combination of this kind of signal and suitable signal processing results in an optimal estimate of frequency-dependent attenuation with a minimum measurement time. PMID:26432190

  1. Seismic motion attenuation relations in Sichuan and adjacent areas

    Institute of Scientific and Technical Information of China (English)

    LEI Jian-cheng; GAO Meng-tan; YU Yan-xiang

    2007-01-01

    The Sichuan and adjacent areas is divided into southwest China region (SWCR) and Sichuan Basin region (SCBR) according to tectonic backgrounds and seismic damage distribution features. 96 modern destructive earthquakes in SWCR and 40 in SCBR are gathered respectively. All their magnitude parameters are checked. Based on the statistic relations between epicentral intensity and magnitude as well as relation between sensible radius and magnitude, the near and far field seismic intensity attenuation features are represented and controlled. And then the seismic intensity attenuation relations along major axis, minor axis and mean axis are established separately. The systematic deviations of surface wave magnitude between China seismograph network and U.S. seismograph network are considered in this paper. By making use of the new attenuation relations of bedrock horizontal ground acceleration response spectrum in west U.S., the attenuation relations of bedrock horizontal ground acceleration response spectrum in SWCR and SCBR are digital transformed based on the attenuation model considering acceleration saturation of distance and magnitude in near field.

  2. Simultaneous inversion for velocity and attenuation by waveform tomography

    Science.gov (United States)

    Gao, Fengxia; Wang, Yanghua

    2016-08-01

    Seismic waveform tomography can invert for the velocity and attenuation (Q- 1) variations simultaneously. For this simultaneous inversion, we propose two strategies for waveform tomography. First, we analyze the contributions of the real part and the imaginary part of the gradients, associated with the velocity and attenuation parameters respectively, and determine that the combination of the real part of the gradient subvector for the velocity parameter and the imaginary part of the gradient subvector for the attenuation parameter would produce an optimal inversion result. Second, we attempt to balance the sensitivities of the objective function to the velocity and the attenuation parameters. Considering the magnitude differences between these two-type parameters in the simultaneous inversion, we apply preliminarily a normalization to both the velocity model and the attenuation model. However, for balancing their sensitivities, we further adjust the corresponding model updates using a tuning factor. We determine this tuning parameter adaptively, based on the sensitivities of these two parameters, at each iteration. Numerical tests demonstrate the feasibility and reliability of these two strategies in full waveform inversion.

  3. Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure

    Directory of Open Access Journals (Sweden)

    Marcos Minicucci

    2016-01-01

    Full Text Available Abstract Background: Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties. Objective: The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Methods: Wistar rats were distributed in four groups: Control (C, Pentoxifylline (PX, Tobacco Smoke (TS, and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%. Results: TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt, and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA and citrate synthase (CS. PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables. Conclusion: TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.

  4. Model-based design of growth-attenuated viruses.

    Directory of Open Access Journals (Sweden)

    Kwang-Il Lim

    2006-09-01

    Full Text Available Live-virus vaccines activate both humoral and cell-mediated immunity, require only a single boosting, and generally provide longer immune protection than killed or subunit vaccines. However, growth of live-virus vaccines must be attenuated to minimize their potential pathogenic effects, and mechanisms of attenuation by conventional serial-transfer viral adaptation are not well-understood. New methods of attenuation based on rational engineering of viral genomes may offer a potentially greater control if one can link defined genetic modifications to changes in virus growth. To begin to establish such links between genotype and growth phenotype, we developed a computer model for the intracellular growth of vesicular stomatitis virus (VSV, a well-studied, nonsegmented, negative-stranded RNA virus. Our model incorporated established regulatory mechanisms of VSV while integrating key wild-type infection steps: hijacking of host resources, transcription, translation, and replication, followed by assembly and release of progeny VSV particles. Generalization of the wild-type model to allow for genome rearrangements matched the experimentally observed attenuation ranking for recombinant VSV strains that altered the genome position of their nucleocapsid gene. Finally, our simulations captured previously reported experimental results showing how altering the positions of other VSV genes has the potential to attenuate the VSV growth while overexpressing the immunogenic VSV surface glycoprotein. Such models will facilitate the engineering of new live-virus vaccines by linking genomic manipulations to controlled changes in virus gene-expression and growth.

  5. Wild type measles virus attenuation independent of type I IFN

    Directory of Open Access Journals (Sweden)

    Horvat Branka

    2008-02-01

    Full Text Available Abstract Background Measles virus attenuation has been historically performed by adaptation to cell culture. The current dogma is that attenuated virus strains induce more type I IFN and are more resistant to IFN-induced protection than wild type (wt. Results The adaptation of a measles virus isolate (G954-PBL by 13 passages in Vero cells induced a strong attenuation of this strain in vivo. The adapted virus (G954-V13 differs from its parental strain by only 5 amino acids (4 in P/V/C and 1 in the M gene. While a vaccine strain, Edmonston Zagreb, could replicate equally well in various primate cells, both G954 strains exhibited restriction to the specific cell type used initially for their propagation. Surprisingly, we observed that both G954 strains induced type I IFN, the wt strain inducing even more than the attenuated ones, particularly in human plasmacytoid Dendritic Cells. Type I IFN-induced protection from the infection of both G954 strains depended on the cell type analyzed, being less efficient in the cells used to grow the viral strain. Conclusion Thus, mutations in M and P/V/C proteins can critically affect MV pathogenicity, cellular tropism and lead to virus attenuation without interfering with the α/β IFN system.

  6. Photon attenuation coefficients and shielding effects of Jordanian building materials

    International Nuclear Information System (INIS)

    Highlights: • The mass attenuation coefficients were calculated for the 50–3000 keV gamma-ray energy. • Values obtained were used to evaluate the protection provided by different building. • Significant benefits could be achieved in using the basement and lower floors. - Abstract: The present study was conducted to investigate the attenuation properties of building materials commonly used in Jordan. The photon interactions with materials of interest were discussed in terms of mass attenuation coefficients for the 50–3000 keV gamma-ray energy range. The linear attenuation coefficients were measured at several photon energies using a NaI(Tl) detector and a narrow beam geometry technique. The values obtained were used to evaluate the shielding provided by different construction styles, against a hypothetical release of radioactive material as a function of the photon energy of the released material. The results obtained revealed that wall mass thickness and material chemical compositions, of the investigated construction styles, are crucial factors in shielding against radiation. An exterior wall with mass thickness of 52 g/cm2, attenuates more than 98% of the incident photons of energy 662 keV. Moreover, the addition of a high density limestone layer to the face of a concrete wall, has increased its shielding effectiveness by about 10%

  7. Attenuation of Landfill Leachate In Unsaturated Sandstone

    Science.gov (United States)

    Butler, A. P.; Brook, C.; Godley, A.; Lewin, K.; Young, C. P.

    Landfill leachate emanating from old "dilute and disperse" sites represents a potential (and in many cases actual) threat to the integrity of groundwater. Indeed, this concern has been included in EU legislation (80/86/EEC), where key contaminants (e.g. ammonia, various toxic organic compounds and heavy metals) are explicitly highlighted in terms of their impact on groundwater. In the UK, whilst there are a substantial number of unlined landfills sited on major aquifers, many of these are in locations where there is a substantial unsaturated zone. Thus, there exists the opportunity for the modification and attenuation of contaminants prior to it encountering the water table. An understanding of likely changes in leachate content and concentrations at such sites will enable a more comprehensive assessment of the potential risks and liabilities posed by such sites to be evaluated. The Burntstump landfill, situated 8 km north of Nottingham (UK), is sited on an outcrop of Sherwood sandstone. The fine friable sand has been quarried since the 1960s and the excavated volume used to store municipal waste. Filling at the site commenced in the mid 1970s and originally was unlined. In 1978 the first of what was to become a series of boreholes was installed within an area of roughly 5 m radius over one of the original waste cells. Cores of the waste and underlying sandstone were extracted and analysed for a range of physical and chemical parameters. The most recent set of analyses were obtained in 2000. The series of investigations therefore provide an important record of leachate migration and modification through the unsaturated zone for over twenty years. The progression of the leachate front is clearly delineated by the chloride concentration profile with an average velocity of around 1.6 m.yr-1. Combining this value with an average (and reasonably uniform) measured moisture content of about 7% gives a mean inter-granular specific discharge of 110 mm.yr-1. An interesting

  8. Attenuation of ultrasonic waves in coal-water slurries

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Raptis, A.C.

    1979-02-01

    Attenuation of ultrasonic waves in coal-water slurries was investigated in the frequency range of 200 kHz to 1 MNZ (up to 30% by weight). The coal used in this study was West Kentucky number nine coal with particle size ranging from 90 to 30 ..mu..m. Attenuation data show a linear dependence on both frequency and coal concentration in the region of investigation. Results were compared with theoretical predictions from the equations derived by Urick, and by Allegra and Hawley. The experimental attenuation was found to be higher than that from the theories by an order of magnitude. The discrepancy is discussed and further investigations are suggested. Results of this work provide valuable information for the design of an ultrasonic mass flowmeter for coal-conversion processes.

  9. Long term attenuation measurements on optical ground wires

    Energy Technology Data Exchange (ETDEWEB)

    Lamarche, L.; Gagnon, D.; Miron, M. [Hydro-Quebec, Varennes, Quebec1 (Canada)

    1996-11-01

    The attenuation stability of optical fibers integrated in optical ground wires (OPGW) cables over temperature and time is of paramount importance in the planning of long distance links. The authors report here a mean thermal attenuation dependence of 5.5{center_dot}10{sup {minus}5} dB/(km{center_dot}C) at 1,550 nm, on a 220 km span of dispersion shifted (DS) fibers of an installed OPGW cable. This optical link is installed in the James Bay region over a 735 kV power line where temperature varies from {minus}40 C to +30 C annually. The data sample presented covers 1.5 year starting December 1993. The data sample presented covers 1.5 year starting December 1993. During that period, the authors also observed a temporal evolution of the attenuation described by the empirical relation A = A{sub 0} (t{minus}t{sub 0}){sup 0.00394}.

  10. Working memory load attenuates emotional enhancement in recognition memory

    Directory of Open Access Journals (Sweden)

    Ewa Aurelia Miendlarzewska

    2013-03-01

    Full Text Available Emotionally arousing stimuli are perceived and remembered better than neutral stimuli. Under threat, this negativity bias is further increased. We investigated whether working memory load can attenuate incidental memory for emotional images. Two groups of participants performed the N-back task with two working memory load levels. In one group, we induced anxiety using a threat-of-shock paradigm to increase attentional processing of negative information. During task performance we incidentally and briefly flashed emotional distracter images which prolonged response times in both load conditions. A subsequent unannounced immediate recognition memory test revealed that when load at exposure had been low, recognition was better for negative items in both participant groups. This enhancement, however, was attenuated under high load, leaving performance on neutral items unchanged regardless of the threat-of-shock manipulation. We conclude that both in threat and in normal states working memory load at exposure can attenuate immediate emotional memory enhancement.

  11. Fiber movements and sound attenuation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1999-01-01

    . The attenation was computed from the fiber diameters and their density, which was found from the mass density. Measured attenuation is lower than the values calculated. Nevertheless, if the density is adjusted, a complete fit is obtained between experimental and theoretical values for frequencies 50-5000 Hz........ The main new result is that the experimental attenuation at low-frequency propagating wave is lower when the fibers move. For wave with frequency 100 Hz in glass wool of density 20 kg/m3, the attenuation of a layer of thickness 0.20 m is 4 dB if the fibers move, and 12 dB if they do not move...

  12. Broadband fractal acoustic metamaterials for low-frequency sound attenuation

    Science.gov (United States)

    Song, Gang Yong; Cheng, Qiang; Huang, Bei; Dong, Hui Yuan; Cui, Tie Jun

    2016-09-01

    We fabricate and experimentally characterize a broadband fractal acoustic metamaterial that can serve to attenuate the low-frequency sounds at selective frequencies ranging from 225 to 1175 Hz. The proposed metamaterials are constructed by the periodic Hilbert fractal elements made of photosensitive resin via 3D printing. In analogy to electromagnetic fractal structures, it is shown that multiple resonances can also be excited in the acoustic counterpart due to their self-similar properties, which help to attenuate the acoustic energy in a wide spectrum. The confinement of sound waves in such subwavelength element is evidenced by both numerical and experimental results. The proposed metamaterial may provide possible alternative for various applications such as the noise attenuation and the anechoic materials.

  13. Consideration of natural attenuation. In remedation contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-04-15

    Upon the proposal submitted by ist Standing committee 5 (Contaminated Sites Committee - ALA) the Federal / State Working Group on Soil protection employed an ad hoc subcommittee dealing with considering natural attenuation in remediating contaminated sites and preparing an inter-State position paper. In the present position paper the way how to consider natural attenuation in practical remediation of contaminated sites is described. The systematic approach outlined allows an understandable decision-finding. A way is shown how the competent soil protection authorities may exercise discretion and in the framework of checking the appropriateness of measures may decide on the implementation of MNA based on a MNA concept (MNA = monitored natural attenuation). It is, however, also explained that when carrying out MNA a decision always made in an individual case is concerned which should be made in a close agreement between the obligated party and the authority.

  14. Rapid Manufacturing - auch mit SLM

    OpenAIRE

    Spierings, Adriaan; Levy, Gideon

    2009-01-01

    Rapid Manufacturing (RM) wurde als Schlagwort in der letzten Zeit insbesondere aus dem Bereich des Selective Laser Sintering (SLS) bekannt. In dieser inzwischen über 15-jährigen Technologieentwicklung wurden in den vergangenen Jahren bedeutende Fortschritte erzielt, die die Bauteileigenschaften nahe an die Anforderungen für End-Teile heran brachten. So ist das RM denn auch weniger aus der Sicht grösserer Losgrösse zu verstehen. Viel mehr bedeutet Rapid Manufacturing, dass die Bauteile nach ei...

  15. Gamma ray attenuation in a developed borate glassy system

    International Nuclear Information System (INIS)

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO–5ZnO–5MgO–14Na2O–-1Li2O–(75−x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E)) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field. - Highlights: • Design new glass system can be used as nuclear radiation shielding material. • Three different systems were used to measure γ-ray attenuation coefficients. • The γ-ray attenuation coefficients in this glass system were measured for 10 γ-energy lines. • Good agreement between experimental, theoretical, and results by other workers have been achieved. • Improvement of σ and HVL by increasing BaO concentration up to 50% in our glassy system

  16. Fast self-attenuation determination of low energy gamma lines.

    Science.gov (United States)

    Haddad, Kh

    2016-09-01

    Linear correlation between self-attenuation factor of 46.5keV ((210)Pb) and the 1764keV, 46.5 counts ratio has been developed in this work using triple superphosphate fertilizer samples. Similar correlation has been also developed for 63.3keV ((238)U). This correlation offers simple, fast, and accurate technique for self-attenuation determination of low energy gamma lines. Utilization of 46.5keV in the ratio has remarkably improved the technique sensitivity in comparison with other work, which used similar concept. The obtained results were used to assess the validity of transmission technique. PMID:27337648

  17. Heat radiative characteristics of ultra-attenuated materials

    Institute of Scientific and Technical Information of China (English)

    Dehong Xia; Yonghong Wu

    2004-01-01

    From the microstructure of heat radiation, the interaction between the incident heat radiative wave and the electromagnetism syntonic wave is analyzed to reveal the emission, absorption, transmission and reflection mechanisms of the incident heat radiative wave in materials. Based on Lorentz dispersion theory, the effect of optical parameters on heat radiative characteristics is also analyzed. The method of ultra-attenuation and nanocrystallization improving the heat radiative characteristics of the material and the emissivity dispersion of the ultra-attenuated materials are brought to light.

  18. Quasi-optical attenuators for ALMA band 10 receiver

    Science.gov (United States)

    Gonzalez, A.; Fujii, Y.; Kaneko, K.; Uzawa, Y.

    2011-12-01

    Simple quasi-optical attenuators based on beam truncation have been designed, fabricated and tried on ALMA band 10 receivers (787-950 GHz) with optimal results. The design is based on physical-optics simulations considering effects of diffraction. The use of these attenuators allows flexibility in the design of the local oscillator (LO) quasi-optical injection scheme depending on the specific performance of components for each of the 73 ALMA band 10 receivers. In particular, they have proven very effective to keep system noise within the stringent ALMA requirements (230 K at 80% of 787-950 GHz band).

  19. Medical image of the week: expiratory imaging accentuates mosaic attenuation

    Directory of Open Access Journals (Sweden)

    Arteaga VA

    2013-05-01

    Full Text Available A 66 year old female presented with cough, fever and marked shortness of breath. Infectious work up was found to be negative. An inspiratory high resolution thoracic CT (HRCT image (A shows faint groundglass and mosaic lung attenuation with subtle centrilobular ill-defined nodules. However, an image obtained on expiration (B shows more obvious mosaic attenuation which suggesting air-trapping. Due to progressive dyspnea, a lung biopsy was performed and revealed a bronchiolocentric cellular interstitial pneumonia with non-caseating granuloma consistent with subacute hypersensitivity pneumonitis.

  20. Evaluation of X ray attenuation by means of radiographic images

    International Nuclear Information System (INIS)

    This paper's main goal is to adopt a qualitative methodology to evaluate the attenuation of x-radiation through X-ray images in polymeric materials plus residual lead. To determinate the images it was initially used an experimental setup at the Laboratory for Materials Diagnostics LACTEC. These results correspond to a more qualitative analysis, even with quantitative answers. Through analysis of radiographic images we can measure the intensity of radiation that goes through the plate, making possible to establish a relationship between the attenuation coefficient and the thickness of the material. (author)

  1. Attenuation of veterinary antibiotics in full-scale vermicomposting of swine manure via the housefly larvae (Musca domestica)

    Science.gov (United States)

    Zhang, Zhijian; Shen, Jianguo; Wang, Hang; Liu, Meng; Wu, Longhua; Ping, Fan; He, Qiang; Li, Hongyi; Zheng, Changfeng; Xu, Xinhua

    2014-10-01

    Animal waste from concentrated swine farms is widely considered to be a source of environmental pollution, and the introduction of veterinary antibiotics in animal manure to ecosystems is rapidly becoming a major public health concern. A housefly larvae (Musca domestica) vermireactor has been increasingly adopted for swine manure value-added bioconversion and pollution control, but few studies have investigated its efficiency on antibiotic attenuation during manure vermicomposting. In this study we explored the capacity and related attenuation mechanisms of antibiotic degradation and its linkage with waste reduction by field sampling during a typical cycle (6 days) of full-scale larvae manure vermicomposting. Nine antibiotics were dramatically removed during the 6-day vermicomposting process, including tetracyclines, sulfonamides, and fluoroquinolones. Of these, oxytetracycline and ciprofloxacin exhibited the greater reduction rate of 23.8 and 32.9 mg m-2, respectively. Environmental temperature, pH, and total phosphorus were negatively linked to the level of residual antibiotics, while organic matter, total Kjeldahl nitrogen, microbial respiration intensity, and moisture exhibited a positive effect. Pyrosequencing data revealed that the dominant phyla related to Firmicutes, Bacteroidetes, and Proteobacteria accelerated manure biodegradation likely through enzyme catalytic reactions, which may enhance antibiotic attenuation during vermicomposting.

  2. Knowledge Exchange Within the Rapid Climate Change Program (RAPID)

    Science.gov (United States)

    Wallace, C.; Srokosz, M.

    2008-12-01

    The Rapid Climate Change Program (RAPID) is a major UK-led science program investigating the susceptibility to and risk of abrupt change in the climate system, with a particular focus on the role of the Atlantic Meridional Overturning Circulation (AMOC). RAPID commenced in 2001, with initial funding to 2008 and has just entered its second phase - RAPID-WATCH - extending some aspects of the program until 2014. Scientifically, a key focus of the program has concerned the development and deployment of a continuous AMOC observing system, although the program has also supported research into a number of other aspects of rapid climate change, including paleo studies of past rapid changes, modeling of the past and future climate, and the development of methods with which to aid the quantification of future risks. Given the societal implications that abrupt climate change associated with the AMOC may have for the North Atlantic region, a major focus within the program has been the implementation of a Knowledge Exchange strategy with which to engage key decision and policy makers within the UK political and industrial sectors. This interaction is especially pertinent for those decision makers involved in the development of adaptive capacities that must incorporate resilience to so-called high-impact, low-probability class threats. We will summarize here the main aspects of our approach, outlining activities/methods used both to satisfy the obvious need to transfer key scientific findings from the program to users, but also in facilitating a return flow of knowledge which can be used by scientists to refine the impact and utility of scientific output. We will draw on particular experience gained from the program's involvement in i: personnel exchanges with central government departments; ii: interaction and co-operation with third party stakeholder organizations (e.g. the UK Climate Impacts Program); and iii: provision of written and oral briefings. Throughout, techniques

  3. Rapid Prototyping Enters Mainstream Manufacturing.

    Science.gov (United States)

    Winek, Gary

    1996-01-01

    Explains rapid prototyping, a process that uses computer-assisted design files to create a three-dimensional object automatically, speeding the industrial design process. Five commercially available systems and two emerging types--the 3-D printing process and repetitive masking and depositing--are described. (SK)

  4. Rapidly Deployed Modular Telemetry System

    Science.gov (United States)

    Varnavas, Kosta A. (Inventor); Sims, William Herbert, III (Inventor)

    2013-01-01

    The present invention is a telemetry system, and more specifically is a rapidly deployed modular telemetry apparatus which utilizes of SDR technology and the FPGA programming capability to reduce the number of hardware components and programming required to deploy a telemetry system.

  5. Rapid thermal processing of semiconductors

    CERN Document Server

    Borisenko, Victor E

    1997-01-01

    Rapid thermal processing has contributed to the development of single wafer cluster processing tools and other innovations in integrated circuit manufacturing environments Borisenko and Hesketh review theoretical and experimental progress in the field, discussing a wide range of materials, processes, and conditions They thoroughly cover the work of international investigators in the field

  6. Evolution of rapid nerve conduction.

    Science.gov (United States)

    Castelfranco, Ann M; Hartline, Daniel K

    2016-06-15

    Rapid conduction of nerve impulses is a priority for organisms needing to react quickly to events in their environment. While myelin may be viewed as the crowning innovation bringing about rapid conduction, the evolution of rapid communication mechanisms, including those refined and enhanced in the evolution of myelin, has much deeper roots. In this review, a sequence is traced starting with diffusional communication, followed by transport-facilitated communication, the rise of electrical signaling modalities, the invention of voltage-gated channels and "all-or-none" impulses, the emergence of elongate nerve axons specialized for communication and their fine-tuning to enhance impulse conduction speeds. Finally within the evolution of myelin itself, several innovations have arisen and have been interactively refined for speed enhancement, including the addition and sealing of layers, their limitation by space availability, and the optimization of key parameters: channel density, lengths of exposed nodes and lengths of internodes. We finish by suggesting several design principles that appear to govern the evolution of rapid conduction. This article is part of a Special Issue entitled SI: Myelin Evolution. PMID:26879248

  7. Whole-body PET/MRI: The effect of bone attenuation during MR-based attenuation correction in oncology imaging

    DEFF Research Database (Denmark)

    Aznar, M.C.; Sersar, Rachida; Saabye, J.;

    2014-01-01

    .3%) and lowest for spongCT (–2.2%, range: 0.0% to –13.7%). Conclusions: In PET/MR imaging using standard MR-AC PET uptake values in soft lesions and bone lesions are underestimated by about 10%. In individual patients this bias can be as high as 22%, which is significant during clinical follow-up exams. If bone...... segmentation is available, then assigning a fixed attenuation value of spongious bone to all bone structures appears reasonable and results in only a minor bias of 5%, or less in uptake values of soft tissue and bone lesions.......Purpose: In combined PET/MRI standard PET attenuation correction (AC) is based on tissue segmentation following dedicated MR sequencing and, typically, bone tissue is not represented. We evaluate PET quantification in whole-body (WB)-PET/MRI following MR-AC without considering bone attenuation...

  8. Research on attenuation characteristic of sound wave in coal or rock body

    Institute of Scientific and Technical Information of China (English)

    NIE Bai-sheng; HE Xue-qiu; LI Xiang-chun; GAO Hong

    2007-01-01

    In order to using power sound wave increase permeability of coal, rules of attenuation of sound wave in coal should be studied. In this paper, characteristic and mechanism of attenuation of sound wave in coal was researched according to acoustic theory and attenuation coefficients was estimated by acoustic parameter of coal. The research results show that the main attenuation mechanism of sound wave in coal is absorption attenuation and scattering attenuation. The absorption attenuation includes viscous absorption, thermal conduction absorption and relaxation absorption. Attenuation coefficient of sound wave in gaseous coal is 38.5 Np/m. Researches on attenuation characteristic of sound wave will provide the theoretical basis for power sound wave improving permeability of coal and accelerating desorption of coal bed gas.

  9. Emission-based estimation of lung attenuation coefficients for attenuation correction in time-of-flight PET/MR

    International Nuclear Information System (INIS)

    In standard segmentation-based MRI-guided attenuation correction (MRAC) of PET data on hybrid PET/MRI systems, the inter/intra-patient variability of linear attenuation coefficients (LACs) is ignored owing to the assignment of a constant LAC to each tissue class. This can lead to PET quantification errors, especially in the lung regions. In this work, we aim to derive continuous and patient-specific lung LACs from time-of-flight (TOF) PET emission data using the maximum likelihood reconstruction of activity and attenuation (MLAA) algorithm. The MLAA algorithm was constrained for estimation of lung LACs only in the standard 4-class MR attenuation map using Gaussian lung tissue preference and Markov random field smoothness priors. MRAC maps were derived from segmentation of CT images of 19 TOF-PET/CT clinical studies into background air, lung, soft tissue and fat tissue classes, followed by assignment of predefined LACs of 0, 0.0224, 0.0864 and 0.0975 cm−1, respectively. The lung LACs of the resulting attenuation maps were then estimated from emission data using the proposed MLAA algorithm. PET quantification accuracy of MRAC and MLAA methods was evaluated against the reference CT-based AC method in the lungs, lesions located in/near the lungs and neighbouring tissues. The results show that the proposed MLAA algorithm is capable of retrieving lung density gradients and compensate fairly for respiratory-phase mismatch between PET and corresponding attenuation maps. It was found that the mean of the estimated lung LACs generally follow the trend of the reference CT-based attenuation correction (CTAC) method. Quantitative analysis revealed that the MRAC method resulted in average relative errors of  −5.2   ±   7.1% and  −6.1   ±   6.7% in the lungs and lesions, respectively. These were reduced by the MLAA algorithm to  −0.8   ±   6.3% and  −3.3   ±   4.7%, respectively. In conclusion, we

  10. Importance of Attenuating Quadriceps Activation Deficits after Total Knee Arthroplasty

    OpenAIRE

    Thomas, Abbey C.; Jennifer E Stevens-Lapsley

    2012-01-01

    Total knee arthroplasty (TKA) is associated with persistent quadriceps dysfunction. Since quadriceps dysfunction impairs functional performance, minimizing quadriceps dysfunction by attenuating central activation deficits early after surgery may improve function later in life. Rehabilitation strategies incorporating neuromuscular electrical stimulation and early, aggressive quadriceps strengthening may prove beneficial. Further, surgical approaches such as minimally invasive TKA may minimize ...

  11. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Majid [Isfahan Nuclear Science and Technology Research Institute (NSTRT), Reactor and Accelerators Research and Development School, Atomic Energy Organization (Iran, Islamic Republic of)], E-mail: m_jalali@entc.org.ir; Mohammadi, Ali [Faculty of Science, Department of Physics, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2008-05-15

    The compounds Na{sub 2}B{sub 4}O{sub 7}, H{sub 3}BO{sub 3}, CdCl{sub 2} and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the {gamma} rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H{sub 3}BO{sub 3} with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  12. The Ultraviolet Attenuation Law in Backlit Spiral Galaxies

    CERN Document Server

    Keel, William C; Holwerda, Benne W; Lintott, Chris J; Schawinski, Kevin

    2014-01-01

    (Abridged) The effective extinction law (attenuation behavior) in galaxies in the emitted ultraviolet is well known only for actively star-forming objects and combines effects of the grain properties, fine structure in the dust distribution, and relative distributions of stars and dust. We use GALEX, XMM Optical Monitor, and HST data to explore the UV attenuation in the outer parts of spiral disks which are backlit by other UV-bright galaxies, starting with candidates provided by Galaxy Zoo participants. Our analysis incorporates galaxy symmetry, using non-overlapping regions of each galaxy to derive error estimates on the attenuation measurements. The entire sample has an attenuation law close to the Calzetti et al. (1994) form; the UV slope for the overall sample is substantially shallower than found by Wild et al. (2011), a reasonable match to the more distant galaxies in our sample but not to the weighted combination including NGC 2207. The nearby, bright spiral NGC 2207 alone gives accuracy almost equal ...

  13. Nuclear Attenuation of Charged Mesons in Deep Inelastic Scattering

    CERN Document Server

    Akopov, N Z; Grigoryan, L A

    2002-01-01

    We propose extended version of stationary string model to describe the nuclear attenuation. This model takes into account flavour content of particles and allows to include into consideration all hadrons created from string. The predictions of the model are compared with experimental results obtained by HERMES collaboration (DESY) on different nuclei (N and Kr).

  14. Attenuation of Rayleigh Surface Waves in a Porous Material

    Institute of Scientific and Technical Information of China (English)

    DEBBOUB Salima; BOUMA(I)ZA Youcef; BOUDOUR Amar; TAHRAOUI Tarek

    2012-01-01

    Using acoustic microscopy at higher frequency,we show the velocity evolutions of surface acoustic waves,in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer.The velocities are obtained from different V(z) curves,which are determined experimentally at a frequency of 600MHz.The analysis of V(z) data yields attenuation that is directly dependent on porosity.On the other hand,αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.%Using acoustic microscopy at higher frequency, we show the velocity evolutions of surface acoustic waves, in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer. The velocities are obtained from different V(z) curves, which are determined experimentally at a frequency of 600 MHz. The analysis of V(z) data yields attenuation that is directly dependent on porosity. On the other hand, αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.

  15. Characteristics of liver tissue for attenuate the gamma radiation

    International Nuclear Information System (INIS)

    It was determined the lineal attenuation coefficient of hepatic tissue before gamma radiation of a source of 137 Cs. When exposing organic material before X or gamma radiation fields, part of the energy of the photons is absorbed by the material, while another part crosses it without producing any effect. The quantity of energy that is absorbed is a measure of the dose that receives the material. The three main mechanisms by means of which the gamma rays interacting with the matter are: The Photoelectric Effect, the Compton dispersion and the Even production; the sum of these three processes is translated in the attenuation coefficient of the radiation. In this work we have used hepatic tissue of bovine, as substitute of the human hepatic tissue, and we have measured the lineal attenuation coefficient for photons of 0.662 MeV. Through a series of calculations we have determined the lineal attenuation coefficient for photons from 10-3 to 10-5 MeV and the measured coefficient was compared with the one calculated. (Author)

  16. 49 CFR 227.117 - Hearing protector attenuation.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION OCCUPATIONAL NOISE EXPOSURE Occupational Noise Exposure for Railroad Operating Employees. § 227.117 Hearing protector attenuation. (a) A railroad shall evaluate hearing... exposure to an 8-hour TWA of 90 decibels or lower, as required by § 227.115. (c) For employees who...

  17. On the effectiveness of mangroves in attenuating cyclone induced waves

    NARCIS (Netherlands)

    Narayan, S.; Suzuki, T.; Stive, M.J.F.; Verhagen, H.J.; Ursem, W.N.J.; Ranasinghe, R.

    2010-01-01

    A study of the effectiveness of mangroves in attenuating cyclone- induced waves was done using the SWAN 40.81 numerical model. Hydraulic parameters during extreme events and local mangrove vegetation parameters were estimated for the Kanika Sands mangrove island near the upcoming Dhamra Port in Oris

  18. Simultaneous amplification and attenuation in isotropic chiral materials

    CERN Document Server

    Mackay, Tom G

    2015-01-01

    The electromagnetic field phasors in an isotropic chiral material (ICM) are superpositions of two Beltrami fields of different handedness. Application of the Bruggeman homogenization formalism to two-component composite materials delivers ICMs wherein Beltrami fields of one handedness attenuate whereas Beltrami waves of the other handedness amplify. One component material is a dissipative ICM, the other an active dielectric material.

  19. Measurement of acoustic attenuation in South Pole ice

    NARCIS (Netherlands)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J.A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S.W.; Bay, R.; Alba, J.L.B.; Beattie, K.; Beatty, J.J.; Bechet, S.; Becker, J.K.; Becker, K.H.; Benabderrahmane, M.L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D.Z.; Bissok, M.; Blaufuss, E.; Boersma, D.J.; Bohm, C.; Boser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D.F.; D'Agostino, M.V.; Danninger, M.; Clercq, C. De; Demirors, L.; Depaepe, O.; Descamps, F.; Desiati, P.; Vries-Uiterweerd, G. de; DeYoung, T.; Diaz-Velez, J.C.; Dreyer, J.; Dumm, J.P.; Duvoort, M.R.; Ehrlich, R.; Eisch, J.; Ellsworth, R.W.; Engdegard, O.; Euler, S.; Evenson, P.A.; Fadiran, O.; Fazely, A.R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M.M.; Fox, B.D.; Franckowiak, A.; Franke, R.; Gaisser, T.K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glusenkamp, T.; Goldschmidt, A.; Goodman, J.A.; Grant, D.; Griesel, T.; Gross, A.; Grullon, S.; Gunasingha, R.M.; Gurtner, M.; Gustafsson, L.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G.C.; Hoffman, K.D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Lafebre, S.J.

    2011-01-01

    Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been

  20. Variable optical attenuator fabricated by direct UV writing

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Færch, Kjartan Ullitz; Andersen, L.U.

    2003-01-01

    It is demonstrated that direct ultraviolet writing of waveguides is a method suitable for mass production of compact variable optical attenuators with low insertion loss, low polarization-dependent loss, and high dynamic range. The fabrication setup is shown to be robust, providing good device...

  1. Soil temperature effect in calculating attenuation and retardation factors.

    Science.gov (United States)

    Paraiba, Lourival Costa; Spadotto, Claudio Aparecido

    2002-09-01

    The effect of annual variation of daily average soil temperature, at different depths, in calculating pesticides ranking indexes retardation factor and attenuation factor is presented. The retardation factor and attenuation factor are two site-specific pesticide numbers, frequently used as screening indicator indexes for pesticide groundwater contamination potential. Generally, in the calculation of these two factors are not included the soil temperature effect on the parameters involved in its calculation. It is well known that the soil temperature affects the pesticide degradation rate, water-air partition coefficient and water-soil partition coefficient. These three parameters are components of the retardation factor and attenuation factor and contribute to determine the pesticide behavior in the environment. The Arrhenius equation, van't Hoff equation and Clausius-Clapeyron equation are used in this work for estimating the soil temperature effect on the pesticide degradation rate, water-air partition coefficient and soil-water partition coefficient, respectively. These dependence relationships, between results of calculating attenuation and retardation factors and the soil temperature at different depths, can aid to understand the potential pesticide groundwater contamination on different weather conditions. Numerical results will be presented with pesticides atrazine and lindane in a soil profile with 20 degrees C constant temperature, minimum and maximum surface temperatures varying and spreading in the soil profile between -5 and 30 degrees C and between 15 and 45 degrees C. PMID:12222785

  2. Experimental determination of the lineal attenuation coefficient of ground

    International Nuclear Information System (INIS)

    This work reports the measurement of the linear attenuation coefficient of ground in order to elaborate a calculus memory for a nuclear medicine installation. The service is placed in the subsoil and the hot room is surrounded by variable, higher than a meter, thicknesses of ground. Owing to the lack of bibliography about the value of the linear attenuation coefficient of ground, we measured it and compared the result with that obtained by the density correction method relative to concrete, using the linear attenuation coefficient value of this material as derived from experimental measures of this material. Measurements were made using a BaF2 scintillation detector and a 137Cs source, which was selected considering the similitude between its energy and the energy of the radiopharmaceutical used in the service for the PET studies, 22Na. Different increasing thicknesses of ground got from areas located near the service were placed as absorbents. The work involves ten experimental points, interposing cumulatively 1.8cm thicknesses of ground each time, between the detector and the source. The results obtained from both methods do not present a significant difference, however, we have concluded that the measured coefficient is more appropriate that the one estimated by the density correction method. Consequently, for calculating the dose rates at different places of the service, the experimentally determined value μ = 0.0884 cm-1 of the linear attenuation coefficient was used. (author)

  3. Body Wave Crustal Attenuation Characteristics in the Garhwal Himalaya, India

    Science.gov (United States)

    Negi, Sanjay S.; Paul, Ajay; Joshi, Anand; Kamal

    2015-06-01

    We estimate frequency-dependent attenuation of P and S waves in Garhwal Himalaya using the extended coda normalization method for the central frequencies 1.5, 2, 3, 4, 6, 8, 10, 12, and 16 Hz, with earthquake hypocentral distance ranging from 27 to 200 km. Forty well-located local earthquake waveforms were used to study the seismic attenuation characteristics of the Garhwal Himalaya, India, as recorded by eight stations operated by Wadia Institute of Himalayan Geology, Dehradun, India, from 2007 to 2012. We find frequency-dependent P and S wave quality factors as defined by the relations Q P = 56 ± 8 f 0.91±0.002 and Q S = 151 ± 8 f 0.84±0.002 by fitting a power-law frequency dependence model for the estimated values over the whole region. Both the Q P and Q S values indicate strong attenuation in the crust of Garhwal Himalaya. The ratio of Q S/ Q P > 1 obtained for the entire analyzed frequency range suggests that the scattering loss is due to a random and high degree of heterogeneities in the earth medium, playing an important role in seismic wave attenuation in the Himalayan crust.

  4. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - I

    Science.gov (United States)

    The bioavailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  5. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - II

    Science.gov (United States)

    The bioabailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  6. Closed-Loop Control of MEMS Variable Optical Attenuator (VOA)

    Institute of Scientific and Technical Information of China (English)

    H. Cai; X. M. Zhang; A. Q. Liu; Y. X. Wang; C. Lu

    2003-01-01

    This paper reports the development of an optical power regulator based on surface-micromachined variable optical attenuators (VOAs). By use of closed-loop control circuits, each VOA module implements the functions of power setpoint tracking, disturbance rejection and ripple suppression.

  7. Lg Attenuation Characteristic of Gujarat Region (Western India)

    Science.gov (United States)

    Jaiswal, Namrata; Singh, Chandrani

    2016-04-01

    We estimate the Lg attenuation characteristics of the Gujarat Region in Western India by using a reliable two-station method. This region comes under the V, IV and III seismicity zone. So, in India this is the seismic active region other than Himalayas, which shows high seismicity. Lg is typically the most prominent short-period seismic phase on high frequency seismogram observed over the continental paths from regional to teleseimic distance. We use data from 15 earthquakes with magnitude > 5 mb and focal depth Lg Q (Q0) values between many pairs of stations. Finally, 5 events with 70 high-quality inter-station paths were selected from 117 possible pairs of stations that are (1) aligned approximately with the source and (2) separated enough to permit the use of the standard two-station method for Lg Q measurement. Spatial variations in Q0 have been noticed across the Gujarat region. Low Q0 ( 300) value. These observations are consistent with the results of the body wave attenuation structure reported for the region. The variations in the attenuation characteristics may be caused due to both the intrinsic and scattering contributions caused by thermal effects, sedimentary layer thickness as well as heterogeneities present below the study region. Our results are found to be comparable with the previous studies of the attenuation characteristics of the Gujarat region.

  8. Gamma ray attenuation in a developed borate glassy system

    Science.gov (United States)

    Saeed, Aly; El shazly, R. M.; Elbashar, Y. H.; Abou El-azm, A. M.; El-Okr, M. M.; Comsan, M. N. H.; Osman, A. M.; Abdal-monem, A. M.; El-Sersy, A. R.

    2014-09-01

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO-5ZnO-5MgO-14Na2O--1Li2O-(75-x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field.

  9. Low-energy gamma ray attenuation characteristics of aviation fuels

    Science.gov (United States)

    Singh, Jag J.; Shen, Chih-Ping; Sprinkle, Danny R.

    1990-01-01

    Am241 (59.5 keV) gamma ray attenuation characteristics were investigated in 270 aviation fuel (Jet A and Jet A-1) samples from 76 airports around the world as a part of world wide study to measure the variability of aviation fuel properties as a function of season and geographical origin. All measurements were made at room temperature which varied from 20 to 27 C. Fuel densities (rho) were measured concurrently with their linear attenuation coefficients (mu), thus providing a measure of mass attenuation coefficient (mu/rho) for the test samples. In 43 fuel samples, rho and mu values were measured at more than one room temperature, thus providing mu/rho values for them at several temperatures. The results were found to be independent of the temperature at which mu and rho values were measured. It is noted that whereas the individual mu and rho values vary considerably from airport to airport as well as season to season, the mu/rho values for all samples are constant at 0.1843 + or - 0.0013 cu cm/gm. This constancy of mu/rho value for aviation fuels is significant since a nuclear fuel quantity gauging system based on low energy gamma ray attenuation will be viable throughout the world.

  10. Low temperature attenuation of sound in restricted geometries

    OpenAIRE

    Lambert, B.; Salin, D.

    1980-01-01

    We have measured the low temperature attenuation of sound at 1 GHz in liquid helium confined in the pores of Vycor glass; our data clearly show the one-dimensional behaviour of the normal density in this restricted geometry; the experimental value is in agreement with fourth sound measurements; anyway the experimental values are three orders of magnitude larger than the theoretical one.

  11. Attenuation of ground vibrations due to different technical sources

    Science.gov (United States)

    Auersch, L.; Said, S.

    2010-09-01

    The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v ˜ r - q where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(- kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

  12. Attenuation of ground vibrations due to different technical sources

    Institute of Scientific and Technical Information of China (English)

    L. Auersch; S. Said

    2010-01-01

    The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v ~ r where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(-kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

  13. Outdoor FSO Communications Under Fog: Attenuation Modeling and Performance Evaluation

    KAUST Repository

    Esmail, Maged Abdullah

    2016-07-18

    Fog is considered to be a primary challenge for free space optics (FSO) systems. It may cause attenuation that is up to hundreds of decibels per kilometer. Hence, accurate modeling of fog attenuation will help telecommunication operators to engineer and appropriately manage their networks. In this paper, we examine fog measurement data coming from several locations in Europe and the United States and derive a unified channel attenuation model. Compared with existing attenuation models, our proposed model achieves a minimum of 9 dB, which is lower than the average root-mean-square error (RMSE). Moreover, we have investigated the statistical behavior of the channel and developed a probabilistic model under stochastic fog conditions. Furthermore, we studied the performance of the FSO system addressing various performance metrics, including signal-to-noise ratio (SNR), bit-error rate (BER), and channel capacity. Our results show that in communication environments with frequent fog, FSO is typically a short-range data transmission technology. Therefore, FSO will have its preferred market segment in future wireless fifth-generation/sixth-generation (5G/6G) networks having cell sizes that are lower than a 1-km diameter. Moreover, the results of our modeling and analysis can be applied in determining the switching/thresholding conditions in highly reliable hybrid FSO/radio-frequency (RF) networks.

  14. PAUT inspection of copper canister: Structural attenuation and POD formulation

    Science.gov (United States)

    Gianneo, A.; Carboni, M.; Mueller, C.; Ronneteg, U.

    2016-02-01

    For inspection of thick-walled (50mm) copper canisters for final disposal of spent nuclear fuel in Sweden, ultrasonic inspection using phased array technique (PAUT) is applied. Because thick-walled copper is not commonly used as a structural material, previous experience on Phased Array Ultrasonic Testing for this type of application is limited. The paper presents the progress in understanding the amplitudes and attenuation changes acting on the Phased Array Ultrasonic Testing inspection of copper canisters. Previous studies showed the existence of a low pass filtering effect and a heterogeneous grain size distribution along the depth, thus affecting both the detectability of defects and their "Probability of Detection" determination. Consequently, the difference between the first and second back wall echoes were not sufficient to determine the local attenuation (within the inspection range), which affects the signal response for each individual defect. Experimental evaluation of structural attenuation was carried out onto step-wedge samples cut from full-size, extruded and pierced & drawn, copper canisters. Effective attenuation values has been implemented in numerical simulations to achieve a Multi Parameter Probability of Detection and to formulate a Model Assisted Probability of Detection through a Monte-Carlo extraction model.

  15. Attenuation law of seismic waves in technical seismicity

    OpenAIRE

    B. Pandula; J. Kondela; K. Pachocka

    2012-01-01

    Blasting operations have positive and negative effects as well. Vibration intensity and seismic safety associated to the blasting operations are highly actual and challenging problem. The presented article describes the results of the analysis and the methodology of evaluation of objects` seismic safety during blasting operations by application of attenuation law of the seismic waves.

  16. Laboratory measurements of seismic attenuation in partially saturated rocks

    Science.gov (United States)

    Chapman, Samuel; Tisato, Nicola; Quintal, Beatriz; Holliger, Klaus

    2014-05-01

    Laboratory measurements of seismic attenuation and transient pore fluid pressure are performed on partially saturated Berea sandstone and synthetic borosilicate samples. Various degrees of water (liquid) and nitrogen (gas) saturation are considered. These measurements are carried out at room temperature and under confining pressures varying from ambient conditions up to 25 MPa. The cylindrical samples are 25 cm long and have a diameter of 7.6 cm. In the context of the experimental setup, the solid frames of both the Berea sandstone and the borosilicate samples can be considered homogenous, which in turn allows for isolating and exploring the effects of partial saturation on seismic attenuation. We employ the sub-resonance method, which is based on the application of a time-harmonic vertical stress to the top of the sample and the measurement of the thus resulting strain. For any given frequency, the attenuation is then inferred as the tangent of the phase shift between the applied stress and the observed strain. Using five equally spaced sensors along the central axis of the cylindrical sample, we measure the transient fluid pressure induced by the application of a step-function-type vertical stress to the top of the sample. Both the sensors and the sample are sealed off with the regard to the confining environment. Together with the numerical results from corresponding compressibility tests based on the quasi-static poroelastic equations, these transient fluid pressure measurements are then used to assist the interpretation of the seismic attenuation measurements.

  17. Tickle me, I think I might be dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid dreams.

    Science.gov (United States)

    Windt, Jennifer M; Harkness, Dominic L; Lenggenhager, Bigna

    2014-01-01

    The contrast between self- and other-produced tickles, as a special case of sensory attenuation for self-produced actions, has long been a target of empirical research. While in standard wake states it is nearly impossible to tickle oneself, there are interesting exceptions. Notably, participants awakened from REM (rapid eye movement-) sleep dreams are able to tickle themselves. So far, however, the question of whether it is possible to tickle oneself and be tickled by another in the dream state has not been investigated empirically or addressed from a theoretical perspective. Here, we report the results of an explorative web-based study in which participants were asked to rate their sensations during self-tickling and being tickled during wakefulness, imagination, and lucid dreaming. Our results, though highly preliminary, indicate that in the special case of lucid control dreams, the difference between self-tickling and being tickled by another is obliterated, with both self- and other produced tickles receiving similar ratings as self-tickling during wakefulness. This leads us to the speculative conclusion that in lucid control dreams, sensory attenuation for self-produced tickles spreads to those produced by non-self dream characters. These preliminary results provide the backdrop for a more general theoretical and metatheoretical discussion of tickling in lucid dreams in a predictive processing framework. We argue that the primary value of our study lies not so much in our results, which are subject to important limitations, but rather in the fact that they enable a new theoretical perspective on the relationship between sensory attenuation, the self-other distinction and agency, as well as suggest new questions for future research. In particular, the example of tickling during lucid dreaming raises the question of whether sensory attenuation and the self-other distinction can be simulated largely independently of external sensory input.

  18. Tickle me, I think I might be dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid dreams.

    Science.gov (United States)

    Windt, Jennifer M; Harkness, Dominic L; Lenggenhager, Bigna

    2014-01-01

    The contrast between self- and other-produced tickles, as a special case of sensory attenuation for self-produced actions, has long been a target of empirical research. While in standard wake states it is nearly impossible to tickle oneself, there are interesting exceptions. Notably, participants awakened from REM (rapid eye movement-) sleep dreams are able to tickle themselves. So far, however, the question of whether it is possible to tickle oneself and be tickled by another in the dream state has not been investigated empirically or addressed from a theoretical perspective. Here, we report the results of an explorative web-based study in which participants were asked to rate their sensations during self-tickling and being tickled during wakefulness, imagination, and lucid dreaming. Our results, though highly preliminary, indicate that in the special case of lucid control dreams, the difference between self-tickling and being tickled by another is obliterated, with both self- and other produced tickles receiving similar ratings as self-tickling during wakefulness. This leads us to the speculative conclusion that in lucid control dreams, sensory attenuation for self-produced tickles spreads to those produced by non-self dream characters. These preliminary results provide the backdrop for a more general theoretical and metatheoretical discussion of tickling in lucid dreams in a predictive processing framework. We argue that the primary value of our study lies not so much in our results, which are subject to important limitations, but rather in the fact that they enable a new theoretical perspective on the relationship between sensory attenuation, the self-other distinction and agency, as well as suggest new questions for future research. In particular, the example of tickling during lucid dreaming raises the question of whether sensory attenuation and the self-other distinction can be simulated largely independently of external sensory input. PMID:25278861

  19. Tickle me, I think I might be dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid dreams

    Directory of Open Access Journals (Sweden)

    Jennifer Michelle Windt

    2014-09-01

    Full Text Available The contrast between self- and other-produced tickles, as a special case of sensory attenuation for self-produced actions, has long been a target of empirical research. While in standard wake states it is nearly impossible to tickle oneself, there are interesting exceptions. Notably, subjects awakened from REM (rapid eye movement- sleep dreams are able to tickle themselves. So far, however, the question of whether it is possible to tickle oneself and be tickled by another in the dream state has not been investigated empirically or addressed from a theoretical perspective. Here, we report the results of an explorative web-based study in which participants were asked to rate their sensations during self-tickling and being tickled during wakefulness, imagination, and lucid dreaming. Our results, though highly preliminary, indicate that in the special case of lucid control dreams, the difference between self-tickling and being tickled by another is obliterated, suggesting that sensory attenuation for self-produced tickles spreads to those produced by non-self dream characters. These preliminary results provide the backdrop for a more general theoretical and metatheoretical discussion of tickling in lucid dreams in a predictive processing framework. We argue that the primary value of our study lies not so much in our results, which are subject to important limitations, but rather in the fact that they enable a new theoretical perspective on the relationship between sensory attenuation, the self-other distinction and agency, as well as suggest new questions for future research. In particular, the example of tickling during lucid dreaming raises the question of whether sensory attenuation and the self-other distinction can be simulated largely independently of external sensory input.

  20. Probucol attenuates atrial autonomic remodeling in a canine model of atrial fibrillation produced by prolonged atrial pacing

    Institute of Scientific and Technical Information of China (English)

    GONG Yong-tai; LI Wei-min; LI Yue; YANG Shu-sen; SHENG Li; YANG Ning; SHAN Hong-bo; XUE Hong-jie; LIU Wei; YANG Bao-feng; DONG De-li; LI Bao-xin

    2009-01-01

    Background We hypothesize that increased atrial oxidative stress and inflammation may play an important role in atrial nerve sprouting and heterogeneous sympathetic hyperinnervation during atrial fibrillation (AF). To test the hypothesis, we examined whether the antioxidant and anti-inflammatory treatment with probucol attenuates atrial autonomic remodeling in a canine model of AF produced by prolonged rapid right atrial pacing. Methods Twenty-one dogs were divided into a sham-operated group, a control group and a probucol group. Dogs in the control group and probucol group underwent right atrial pacing at 400 beats per minute for 6 weeks, and those in the probucol group received probucol 1 week before rapid atrial pacing until pacing stopped. After 6-week rapid atrial pacing, general properties including left atrial structure and function, atrial hemodynamics and the inducibility and duration of AF were measured in all the groups. Atrial oxidative stress markers and serum C-reactive protein (CRP) concentration were estimated. The degree of nerve sprouting and sympathetic innervation at the right atrial anterior wall (RAAW) and the left atrial anterior wall (LAAW) were quantified by immunohistochemistry, atdal norepinephrine contents were also detected. Atrial beta-nerve growth factor (beta-NGF) mRNA and protein expression at the RAAW and LAAW were assessed by real-time quantitative RT-PCR and Western blotting respectively. Results Atrial tachypacing induced significant nerve sprouting and heterogeneous sympathetic hyperinnervation, and the magnitude of nerve sprouting and hyperinnervation was higher in the RAAW than in the LAAW. Atrial beta-NGF mRNA and protein levels were significantly increased at the RAAW and LAAW, and the upregulation of beta-NGF expression was greater at the RAAW than at the LAAW in the control group. The beta-NGF protein level was positively correlated with the density of sympathetic nerves in all groups. Probucol decreased the increase of

  1. Modeling transmission and scatter for photon beam attenuators.

    Science.gov (United States)

    Ahnesjö, A; Weber, L; Nilsson, P

    1995-11-01

    The development of treatment planning methods in radiation therapy requires dose calculation methods that are both accurate and general enough to provide a dose per unit monitor setting for a broad variety of fields and beam modifiers. The purpose of this work was to develop models for calculation of scatter and transmission for photon beam attenuators such as compensating filters, wedges, and block trays. The attenuation of the beam is calculated using a spectrum of the beam, and a correction factor based on attenuation measurements. Small angle coherent scatter and electron binding effects on scattering cross sections are considered by use of a correction factor. Quality changes in beam penetrability and energy fluence to dose conversion are modeled by use of the calculated primary beam spectrum after passage through the attenuator. The beam spectra are derived by the depth dose effective method, i.e., by minimizing the difference between measured and calculated depth dose distributions, where the calculated distributions are derived by superposing data from a database for monoenergetic photons. The attenuator scatter is integrated over the area viewed from the calculation point of view using first scatter theory. Calculations are simplified by replacing the energy and angular-dependent cross-section formulas with the forward scatter constant r2(0) and a set of parametrized correction functions. The set of corrections include functions for the Compton energy loss, scatter attenuation, and secondary bremsstrahlung production. The effect of charged particle contamination is bypassed by avoiding use of dmax for absolute dose calibrations. The results of the model are compared with scatter measurements in air for copper and lead filters and with dose to a water phantom for lead filters for 4 and 18 MV. For attenuated beams, downstream of the buildup region, the calculated results agree with measurements on the 1.5% level. The accuracy was slightly less in situations

  2. Modeling transmission and scatter for photon beam attenuators.

    Science.gov (United States)

    Ahnesjö, A; Weber, L; Nilsson, P

    1995-11-01

    The development of treatment planning methods in radiation therapy requires dose calculation methods that are both accurate and general enough to provide a dose per unit monitor setting for a broad variety of fields and beam modifiers. The purpose of this work was to develop models for calculation of scatter and transmission for photon beam attenuators such as compensating filters, wedges, and block trays. The attenuation of the beam is calculated using a spectrum of the beam, and a correction factor based on attenuation measurements. Small angle coherent scatter and electron binding effects on scattering cross sections are considered by use of a correction factor. Quality changes in beam penetrability and energy fluence to dose conversion are modeled by use of the calculated primary beam spectrum after passage through the attenuator. The beam spectra are derived by the depth dose effective method, i.e., by minimizing the difference between measured and calculated depth dose distributions, where the calculated distributions are derived by superposing data from a database for monoenergetic photons. The attenuator scatter is integrated over the area viewed from the calculation point of view using first scatter theory. Calculations are simplified by replacing the energy and angular-dependent cross-section formulas with the forward scatter constant r2(0) and a set of parametrized correction functions. The set of corrections include functions for the Compton energy loss, scatter attenuation, and secondary bremsstrahlung production. The effect of charged particle contamination is bypassed by avoiding use of dmax for absolute dose calibrations. The results of the model are compared with scatter measurements in air for copper and lead filters and with dose to a water phantom for lead filters for 4 and 18 MV. For attenuated beams, downstream of the buildup region, the calculated results agree with measurements on the 1.5% level. The accuracy was slightly less in situations

  3. Rapid and sustained cost management

    International Nuclear Information System (INIS)

    Accenture helps clients develop comprehensive, process-driven strategies for rapid and sustained cost management that leverage deep insights and analytics. This approach enables companies to gain operating cost advantages by rationalizing, simplifying and automating current operating capabilities. It drives structural cost advantages by optimizing business mix, capital structure, organizational structure and geographic presence. This paper discussed how successful companies achieve high performance during times of economic turmoil. It also discussed the value of the winner's strategy in terms of rapid and sustained cost management (RSCM). It discussed how Accenture operates and its leveraged capabilities, improved efficiency, margins and cash flow while maintaining customer service levels. Building structural advantage and the Accenture difference were also discussed. It was concluded that RSCM is one vital way that Accenture can help companies achieve success. 4 figs

  4. Three-dimensional attenuation structure beneath North Island, New Zealand

    Science.gov (United States)

    Satake, Kenji; Hashida, Toshihiko

    1989-03-01

    Three-dimensional attenuation structure beneath North Island, New Zealand is determined by inversion of seismic intensity data. The method developed by Hashida and Shimazaki is used; the seismic intensity is converted to the maximum acceleration of the S-wave to obtain the acceleration at a point source and the attenuation structure. Because seismic intensity data have been accumulated on a uniform scale in New Zealand since the 1950's, we were able to use more than 2000 seismic intensity data from 26 earthquakes. The results show a remarkable contrast in the attenuation structure. In the top crustal layer, a low-Q area corresponding to the Central Volcanic Region is found. This low-Q area becomes wider to the northeast of North Island, suggesting that the Central Volcanic Region continues to the Havre Trough, a young back-arc basin. The southeastern part of the upper mantle beneath North Island shows high Q while the northwestern part shows low Q. The cross section shows that the high-Q region is dipping to the northwest, with a large amount of dip in the northeast and a smaller dip in the southwestern part of North Island. A comparison of the attenuation structure with microearthquake distribution indicates that this high-Q zone is the obliquely subducting Pacific plate. A zone of abnormally low Q which has cut the high-Q slab is found at a depth range of 130 to 230 km beneath the active volcanoes in the Taupo Volcanic Zone. A tear in the Pacific plate is suggested by this discontinuity in the attenuation structure. (1984).

  5. Rapid Sampling from Sealed Containers

    International Nuclear Information System (INIS)

    The authors have developed several different types of tools for sampling from sealed containers. These tools allow the user to rapidly drill into a closed container, extract a sample of its contents (gas, liquid, or free-flowing powder), and permanently reseal the point of entry. This is accomplished without exposing the user or the environment to the container contents, even while drilling. The entire process is completed in less than 15 seconds for a 55 gallon drum. Almost any kind of container can be sampled (regardless of the materials) with wall thicknesses up to 1.3 cm and internal pressures up to 8 atm. Samples can be taken from the top, sides, or bottom of a container. The sampling tools are inexpensive, small, and easy to use. They work with any battery-powered hand drill. This allows considerable safety, speed, flexibility, and maneuverability. The tools also permit the user to rapidly attach plumbing, a pressure relief valve, alarms, or other instrumentation to a container. Possible applications include drum venting, liquid transfer, container flushing, waste characterization, monitoring, sampling for archival or quality control purposes, emergency sampling by rapid response teams, counter-terrorism, non-proliferation and treaty verification, and use by law enforcement personnel during drug or environmental raids

  6. IRON PRECIPITATION AND ARSENIC ATTENUATION - ASSESSMENT OF ARSENIC NATURAL ATTENUATION OF THE SUBSURFACE USING A GEOCHEMICAL MODEL (PHREEQC)

    Science.gov (United States)

    Laboratory experiments show that amorphous and poorly crystallized ferric iron hydroxides have much greater capacity to attenuate arsenic compared to clays and other aluminosilicate minerals. Studies (e.g., Lin and Qvarfort, 1996) showed that a sudden change in geochemical condit...

  7. MRI-guided attenuation correction in whole-body PET/MR : assessment of the effect of bone attenuation

    NARCIS (Netherlands)

    Akbarzadeh, A.; Ay, M. R.; Ahmadian, A.; Alam, N. Riahi; Zaidi, H.

    2013-01-01

    Hybrid PET/MRI presents many advantages in comparison with its counterpart PET/CT in terms of improved soft-tissue contrast, decrease in radiation exposure, and truly simultaneous and multi-parametric imaging capabilities. However, the lack of well-established methodology for MR-based attenuation co

  8. CT-based attenuation and scatter correction compared with uniform attenuation correction in brain perfusion SPECT imaging for dementia

    Science.gov (United States)

    Gillen, Rebecca; Firbank, Michael J.; Lloyd, Jim; O'Brien, John T.

    2015-09-01

    This study investigated if the appearance and diagnostic accuracy of HMPAO brain perfusion SPECT images could be improved by using CT-based attenuation and scatter correction compared with the uniform attenuation correction method. A cohort of subjects who were clinically categorized as Alzheimer’s Disease (n=38 ), Dementia with Lewy Bodies (n=29 ) or healthy normal controls (n=30 ), underwent SPECT imaging with Tc-99m HMPAO and a separate CT scan. The SPECT images were processed using: (a) correction map derived from the subject’s CT scan or (b) the Chang uniform approximation for correction or (c) no attenuation correction. Images were visually inspected. The ratios between key regions of interest known to be affected or spared in each condition were calculated for each correction method, and the differences between these ratios were evaluated. The images produced using the different corrections were noted to be visually different. However, ROI analysis found similar statistically significant differences between control and dementia groups and between AD and DLB groups regardless of the correction map used. We did not identify an improvement in diagnostic accuracy in images which were corrected using CT-based attenuation and scatter correction, compared with those corrected using a uniform correction map.

  9. Adult-onset phenylketonuria with rapidly progressive dementia and parkinsonism.

    Science.gov (United States)

    Tufekcioglu, Zeynep; Cakar, Arman; Bilgic, Basar; Hanagasi, Hasmet; Gurvit, Hakan; Emre, Murat

    2016-06-01

    Phenylketonuria (PKU) is an autosomal recessive metabolic disorder due to mutations in the phenylalanine hydroxylase (PAH) gene, which converts phenylalanine (PHE) to tyrosine. Although it is principally a childhood disorder, in rare cases, the first signs of PKU may develop in late adulthood resembling common neurological diseases. Here we report a 59-year-old, previously normal functioning man who was admitted with blurred vision, cognitive problems, and gait difficulty that began 8 months before. He had brisk reflexes and left side dominant parkinsonism. His Mini-Mental State Examination (MMSE) score was 25/30, and neuropsychological evaluation revealed a dysexecutive syndrome with simultanagnosia and constructional apraxia. His Clinical Dementia Rating score (CDR) was 1. Cranial MRI revealed bilateral diffuse hyperintense lesions in parietal and occipital white matter in T2, fluid-attenuated inversion recovery, and diffusion weighted images. Diagnostic workup for rapidly progressive dementias was all normal except PHE level which was found to be highly elevated (1075 μmol/L, normal 39-240 μmol/L) with normal tyrosine level (61.20 μmol/L, normal 35-100 μmol/L). Three months after PHE-restricted diet, his cognitive impairment and signs of parkinsonism significantly improved, with MRI scan unchanged. This case demonstrates that late-onset PKU is a rare, treatable cause of rapidly progressive dementia and parkinsonism with certain constellations such as consanguinity and white matter abnormalities (WMAs) in imaging. PMID:26962957

  10. PREPARATION AND MICROWAVE ATTENUATION PROPERTY IN THE X BAND OF SiC–C COMPOSITES

    Directory of Open Access Journals (Sweden)

    ZEHUA ZHOU

    2011-02-01

    Full Text Available For developing an effective, low-cost method on preparation of microwave attenuation material, SiC–C composites with different additions of graphite grain were fabricated with solid phase sintering and liquid phase sintering, respectively. The microwave attenuation and the relative electrical properties of composites in the X band were measured. The results show that both methods are cost-effective and easily controllable processes and Solid phase sintering was more suitable to obtain SiC-C attenuation composites than the liquid phase sintering. The composite with 3 wt.% C prepared by solid phase sintering exhibited the best microwave attenuation, the biggest attenuation was -40.5 dB and most attenuations were above -30 dB in the whole X band. Furthermore, the microwave attenuation of composites depended strongly on the C additions; Match of interface of wave impedance and high wave consumption are both necessary for microwave attenuation materials.

  11. Methodology for Estimating Times of Remediation Associated with Monitored Natural Attenuation

    Science.gov (United States)

    Chapelle, Francis H.; Widdowson, Mark A.; Brauner, J. Steven; Mendez, Eduardo; Casey, Clifton C.

    2003-01-01

    http://www.cee.vt.edu/NAS/ Application of NAS illustrates several general characteristics shared by all TOR problems. First, the distance of stabilization of a contaminant plume is strongly dependent on the natural attenuation capacity of particular ground-water systems. The time that it takes a plume to reach a steady-state configuration, however, is independent of natural attenuation capacity. Rather, the time of stabilization is most strongly affected by the sorptive capacity of the aquifer, which is dependent on the organic matter content of the aquifer sediments, as well as the sorptive properties of individual contaminants. As a general rule, a high sorptive capacity retards a plume.s growth or shrinkage, and increases the time of stabilization. Finally, the time of NAPL dissolution depends largely on NAPL mass, composition, geometry, and hydrologic factors, such as ground-water flow rates. An example TOR analysis for petroleum hydrocarbon NAPL was performed for the Laurel Bay site in South Carolina. About 500 to 1,000 pounds of gasoline leaked into the aquifer at this site in 1991, and the NAS simulations suggested that TOR would be on the order of 10 years for soluble and poorly sorbed compounds, such as benzene and methyl tertiary-butyl ether (MTBE). Conversely, TOR would be on the order of 40 years for less soluble, more strongly sorbed compounds, such as toluene, ethylbenzene, and xylenes (TEX). These TOR estimates are roughly consistent with contaminant concentrations observed over 10 years of monitoring at this site where benzene and MTBE concentrations were observed to decrease rapidly and are approaching regulatory maximum concentration limits, whereas toluene, ethylbenzene, and xylene concentrations decreased at a slower rate and have remained relatively high. An example TOR analysis for petroleum hydrocarbon NAPL was performed for the Laurel Bay site in South Carolina. About 500 to 1,000 pounds of gasoline leaked into the a

  12. Measurment and Interpretation of Seismic Attenuation for Hydrocarbon Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; Luca Duranti; James Rector; Steve Pride

    2007-12-31

    This research project is the combined effort of several leading research groups. Advanced theoretical work is being conducted at the Lawrence Berkeley National Laboratory. Here, the fundamental controls on loss mechanisms are being examined, primarily by use of numerical models of heterogeneous porous media. At the University of California, Berkeley, forward modeling is combined with direct measurement of attenuation. This forward modeling provides an estimate of the influence of 1/Q on the observed seismic signature. Direct measures of losses in Vertical Seismic Profiles (VSPs) indicate mechanisms to separate scattering versus intrinsic losses. At the Colorado School of Mines, low frequency attenuation measurements are combined with geologic models of deep water sands. ChevronTexaco is our corporate cosponsor and research partner. This corporation is providing field data over the Genesis Field, Gulf of Mexico. In addition, ChevronTexaco has rebuilt and improved their low frequency measurement system. Soft samples representative of the Genesis Field can now be measured for velocities and attenuations under reservoir conditions. Throughout this project we have: Assessed the contribution of mechanical compaction on time-lapse monitoring; Developed and tested finite difference code to model dispersion and attenuation; Heterogeneous porous materials were modeled and 1/Q calculated vs. frequency; 'Self-affine' heterogeneous materials with differing Hurst exponent modeled; Laboratory confirmation was made of meso-scale fluid motion influence on 1/Q; Confirmed theory and magnitude of layer-based scattering attenuation at Genesis and at a shallow site in California; Scattering Q's of between 40 and 80 were obtained; Measured very low intrinsic Q's (2-20) in a partially saturated vadose zone VSP; First field study to separate scattering and intrinsic attenuation in real data set; Revitalized low frequency device at ChevronTexaco's Richmond lab

  13. Guided wave attenuation in coated pipes buried in sand

    Science.gov (United States)

    Leinov, Eli; Cawley, Peter; Lowe, Michael J. S.

    2016-02-01

    Long-range guided wave testing (GWT) is routinely used for the monitoring and detection of corrosion defects in above ground pipelines in various industries. The GWT test range in buried, coated pipelines is greatly reduced compared to aboveground pipelines due to energy leakage into the embedding soil. In this study, we aim to increase test ranges for buried pipelines. The effect of pipe coatings on the T(0,1) and L(0,2) guided wave attenuation is investigated using a full-scale experimental apparatus and model predictions. Tests are performed on a fusion-bonded epoxy (FBE)-coated 8" pipe, buried in loose and compacted sand over a frequency range of 10-35 kHz. The application of a low impedance coating is shown to effectively decouple the influence of the sand on the ultrasound leakage from the buried pipe. We demonstrate ultrasonic isolation of a buried pipe by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both pipe and sand and the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is substantially reduced, in the range of 0.3-1.2 dBm-1 for loose and compacted sand conditions, compared to buried FBE-coated pipe without the PE-foam, where the measured attenuation is in the range of 1.7-4.7 dBm-1. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry technique and used in model predictions of guided wave propagation in a buried coated pipe. Good agreement is found between the attenuation measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges, so such coatings would be attractive for new pipeline installations.

  14. Estimation of compressional seismic wave attenuation of carbonate rocks in Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Bouchaala, Fateh; Ali, Mohammed Y.; Farid, Asam

    2014-07-01

    The subsurface geology of Abu Dhabi in the United Arab Emirates is primarily composed of carbonate rocks. Such media are known to be highly heterogeneous. Very few studies have attempted to estimate attenuation in carbonate rocks. In Abu Dhabi no attenuation profile has been published. This study provides the first seismic wave attenuation profiles in Abu Dhabi using dense array of VSP data. We estimated three attenuation profiles: the apparent, the scattering, and the intrinsic attenuations. The apparent attenuation profile was computed using amplitude decay and spectral-ratio methods. The scattering attenuation profile was estimated using a generalized reflection-transmission matrix forward model. It is usually estimated from the sonic log, but to be more consistent with the apparent attenuation, we succeeded in this paper to estimate it from the VSP data. We subtracted the scattering attenuation from the apparent attenuation to deduce the intrinsic attenuation. The results of the study indicate that the scattering attenuation is significant compared to the published studies that are mainly based on clastic rocks. The high scattering attenuation can reach up to 0.02. It can be explained by the strong heterogeneity of the carbonate rocks. This study demonstrates that the Simsima and Rus Formations have considerable scattering and intrinsic attenuations. These formations are considered aquifers in Abu Dhabi; we therefore interpreted this high intrinsic attenuation zones to be due to the heterogeneity and to the fluids contained in these formations. The Umm-Er-Radhuma Formation is a more homogenous formation with limited aquifer potential. Hence, scattering and intrinsic attenuations of the Umm-Er-Radhuma Formation are low.

  15. Production and efficacy of an attenuated live vaccine against contagious ovine ecthyma

    Directory of Open Access Journals (Sweden)

    Attilio Pini

    2008-09-01

    Full Text Available Contagious ecthyma is caused by the orf virus, a member of the family Poxviridae, genus Parapoxvirus. Morbidity in affected sheep flocks is approximately 100%, while mortality varies between 1% and 10%. A live attenuated vaccine was produced by the Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise ‘G. Caporale’. Quality control was performed in accordance with the European Pharmacopoeia. A wild virus strain was attenuated through serial passages on primary chicken embryo fibroblast tissue cultures. The virus suspension was treated according to standard procedures and freeze dried. The immunising dose was 1 ml containing 104,5TCID50, administered intramuscularly. The safety of the vaccine was successfully tested by intramuscular inoculation of 20 susceptible sheep and 20 lambs with the routine dose, 10 times the immunising dose and two normal doses administered at seven-day intervals. The efficacy of the vaccine was tested using three groups of susceptible animals. The first group included 10 lambs and the second 10 adult sheep; the animals were immunised intramuscularly with 1 ml of the reconstituted vaccine. The third group, used as controls, included five sheep and five lambs. Serological reactivity was monitored by indirect enzyme-linked immunosorbent assay (ELISA. The animals were challenged 30 days later with a pathogenic strain administered intradermally along the labial area. Vaccinated animals did not show any clinical signs of disease, whereas all the controls developed typical signs of contagious ecthyma. To confirm the efficacy of the vaccine, a field trial was conducted in four flocks affected by the disease. The trial showed that the vaccine was able to block the normal course of the disease and induce rapid recovery.

  16. Remission of classic rapid cycling bipolar disorder with levothyroxine augmentation therapy in a male patient having clinical hypothyroidism

    OpenAIRE

    Chen, Pao-Huan

    2015-01-01

    Pao-Huan Chen, Yu-Jui Huang Department of Psychiatry, Taipei Medical University Hospital, Taipei, Taiwan Abstract: The literature suggests that patients with bipolar disorder, particularly females, have greater vulnerability to rapid cycling features. Levothyroxine therapy might be potentially useful to attenuate mood instability in this patient group. In contrast, reports on male patients remain limited and controversial. Herein, we report a 32-year-old male patient who had bipola...

  17. Remission of classic rapid cycling bipolar disorder with levothyroxine augmentation therapy in a male patient having clinical hypothyroidism

    OpenAIRE

    Chen PH; Huang YJ

    2015-01-01

    Pao-Huan Chen, Yu-Jui Huang Department of Psychiatry, Taipei Medical University Hospital, Taipei, Taiwan Abstract: The literature suggests that patients with bipolar disorder, particularly females, have greater vulnerability to rapid cycling features. Levothyroxine therapy might be potentially useful to attenuate mood instability in this patient group. In contrast, reports on male patients remain limited and controversial. Herein, we report a 32-year-old male patient who had bipolar 1 ...

  18. Rapid diagnosis of bacteric meningitis

    Directory of Open Access Journals (Sweden)

    Sara Giordana Rimoldi

    2010-09-01

    Full Text Available Gram stain and bacterial antigen detection are economic and rapid tests for the identification of the bacteria in cerebrospinal fluid (CSF for the diagnosis of meningitis. Even if culture is the gold standard of these diagnosis, it requires long time (growth time. The purpose of our study was to compare in the laboratory diagnosis of meningitis real time PCR (Eurospital, Italy. with standard methods. Samples were collected in patients referred to L. Sacco Universital Hospital (range of age: 16 to 70 years from September 2008 to July 2009. 9 out of 130 CFS samples investigated were positive in PCR but they produced different results to the other methods used.

  19. Rapidly Adaptable Instrumentation Tester (RAIT)

    International Nuclear Information System (INIS)

    Emerging technologies in the field of ''Test ampersand Measurement'' have recently enabled the development of the Rapidly Adaptable Instrumentation Tester (RAIT). Based on software developed with LabVIEW, the RAIT design enables quick reconfiguration to test and calibrate a wide variety of telemetry systems. The consequences of inadequate testing could be devastating if a telemetry system were to fail during an expensive flight mission. Supporting both open-bench testing as well as automated test sequences, the RAIT has significantly lowered total time required to test and calibrate a system. This has resulted in an overall lower per unit testing cost than has been achievable in the past

  20. Comparison of dexmedetomidine and lignocaine on attenuation of airway and pressor responses during tracheal extubation

    Directory of Open Access Journals (Sweden)

    Vivek Bharti Sharma

    2014-01-01

    Full Text Available Background: Haemodynamic stability and rapid emergence after general anaesthesia used in spinal surgery is a common practice, the goal of which is to permit early neurological motor and sensory examination. Extubation is almost always associated with hypertension, increased airway response and arrhythmias. We have compared the effects of the α-2 agonist Dexmedetomidine and Lignocaine given at the end of the procedure on attenuation of airway and pressor responses following tracheal extubation. This study is a randomised, placebo-controlled, double-blinded study. Materials and Methods: Sixty ASA I-III patients, aged 18-70 years, scheduled to undergo spinal surgery at the level of thoracic, lumbar or sacral region were randomly divided into three groups. Balanced general anaesthesia comprising standard procedures and drugs were used for monitoring, induction and maintenance. At the last skin suture, inhalation anaesthetic was discontinued. After turning the patient supine and return of spontaneous efforts, in Group D Dexmedetomidine 0.5 μg/kg, in Group L Lignocaine 1.5 mg/kg and in Group P normal saline (10 ml were administered as bolus intravenously over 60 seconds. Systolic, diastolic and mean arterial pressures and heart rate were recorded before intravenous administration and also every minute for 3 minutes, at 5, 10 and 15 minutes post-extubation. Duration of emergence and extubation were noted and attenuation of airway response and quality of extubation was evaluated on cough grading. Results: Mean arterial pressures and heart rate were higher in Group L and Group P than in Group D but not statistically significant. The duration of emergence, extubation and recovery were comparable in all the groups (P > 0.05. Extubation Quality Scores was 1 in 80%, 2 in 20% in Group D; in Group L, the quality scores were 1 for 55%, 2 for 45% and I Group P 1 for 35%, 2 for 45% and 3 for 20% of the patients. The requirement of rescue analgesia was also less

  1. Wave attenuation model for dephasing and measurement of conditional times

    Indian Academy of Sciences (India)

    A M Jayannavar; Colin Benjamin

    2002-08-01

    Inelastic scattering induces dephasing in mesoscopic systems. An analysis of previous models to simulate inelastic scattering in such systems is presented and a relatively new model based on wave attenuation is introduced. The problem of Aharonov–Bohm (AB) oscillations in conductance of a mesoscopic ring is studied. We show that the conductance is symmetric under flux reversal and the visibility of AB oscillations decays to zero as a function of the incoherence parameter, signaling dephasing. Further the wave attenuation model is applied to a fundamental problem in quantum mechanics, that of the conditional (reflection/transmission) times spent in a given region of space by a quantum particle before scattering off from that region.

  2. Experimental and theoretical studies on visible light attenuation in water

    CERN Document Server

    Simpson, A; Cho, H J; Liu, H

    2014-01-01

    In this study we describe lab experiments on determining the above water reflectance Rrs coefficient, and the water attenuation coefficient Kd for fresh water. Different types of screens (totally absorbent, gray, etc.) were submerged in water (0-0.6 m) and illuminated from outside. The spectral density of the water leaving radiance was measured for different depths. The results were ran by a code which took into account the geometry of the incident irradiation, the geometry of the screen under water, and boundary conditions at the water surface provided by the radiation transfer theory. From the experimental data and our model we obtain the spectral distribution of the attenuation coefficient for fresh water and compared it with other data in literature. These experiments, performed in the Nonlinear Wave Lab at ERAU# represent just a preliminary calibration of the experimental protocol. More tests with water of different degrees of turbidity, and possibly wave filed at the water surface are in progress and wi...

  3. Attenuation of earthquake generated P waves in Iraq

    International Nuclear Information System (INIS)

    This work is the first attempt to investigate seismic wave attenuation in Iraq. it studies longitudinal waves recorded at Baghdad (BHD) and Musul (MSL) observatories from earthquakes originated in Turkey and in Iran. Thirty seven earthquakes were chosen for this investigation, twenty three of them were recorded at Baghdad observatory, and fourteen were recorded at Mousul observatory. The epicenters of some of these earthquakes are located within the Iraqi territory; the rest of the events have their epicenters on the Iraqi-Iran borders or on the Turkish and Iranian sides of the boeder. The path of the investigated earthquakes cover the central, north and eastern regions of Iraq; with magnitudes (mb) varying between (4.1-5.7). The amplitude-distance curve method was utilized in this investigation. The mean attenuation value obtained for the study area was 0.0035 km-1. (authors). 19 refs., 7 tabs., 9 figs

  4. Assessing aerobic natural attenuation of trichloroethene at four DOE sites

    Energy Technology Data Exchange (ETDEWEB)

    Koelsch, Michael C. [North Wind, Inc., Idaho Falls, ID (United States); Starr, Robert C. [North Wind, Inc., Idaho Falls, ID (United States); Sorenson, Jr., Kent S. [CDM, Inc., Denver, CO (United States)

    2005-03-01

    A 3-year Department of Energy Environmental Science Management Program (EMSP) project is currently investigating natural attenuation of trichloroethane (TCE) in aerobic groundwater. This presentation summarizes the results of a screening process to identify TCE plumes at DOE facilities that are suitable for assessing the rate of TCE cometabolism under aerobic conditions. In order to estimate aerobic degradation rates, plumes had to meet the following criteria: TCE must be present in aerobic groundwater, a conservative co-contaminant must be present and have approximately the same source as TCE, and the groundwater velocity must be known. A total of 127 TCE plumes were considered across 24 DOE sites. The four sites retained for the assessment were: (1) Brookhaven National Laboratory, OU III; (2) Paducah Gaseous Diffusion Plant, Northwest Plume; (3) Rocky Flats Environmental Technology Site, Industrialized Area--Southwest Plume and 903 Pad South Plume; and (4) Savannah River Site, A/M Area Plume. For each of these sites, a co-contaminant derived from the same source area as TCE was used as a nonbiodegrading tracer. The tracer determined the extent to which concentration decreases in the plume can be accounted for solely by abiotic processes such as dispersion and dilution. Any concentration decreases not accounted for by these processes must be explained by some other natural attenuation mechanism. Thus, ''half-lives'' presented herein are in addition to attenuation that occurs due to hydrologic mechanisms. This ''tracer-corrected method'' has previously been used at the DOE's Idaho National Engineering and Environmental Laboratory in conjunction with other techniques to document the occurrence of intrinsic aerobic cometabolism. Application of this method to other DOE sites is the first step to determining whether this might be a significant natural attenuation mechanism on a broader scale. Application of the tracer

  5. Electroacupuncture attenuates neuropathic pain after brachial plexus injury

    Institute of Scientific and Technical Information of China (English)

    Shenyu Zhang; Hailiang Tang; Junming Zhou; Yudong Gu

    2014-01-01

    Electroacupuncture has traditionally been used to treat pain, but its effect on pain following brachial plexus injury is still unknown. In this study, rat models of an avulsion injury to the left brachial plexus root (associated with upper-limb chronic neuropathic pain) were given electroacu-puncture stimulation at bilateralQuchi(LI11),Hegu(LI04),Zusanli(ST36) andYanglingquan (GB34). After electroacupuncture therapy, chronic neuropathic pain in the rats’ upper limbs was signiifcantly attenuated. Immunolfuorescence staining showed that the expression of β-endorphins in the arcuate nucleus was signiifcantly increased after therapy. Thus, experimental ifndings indi-cate that electroacupuncture can attenuate neuropathic pain after brachial plexus injury through upregulatingβ-endorphin expression.

  6. Material identification based upon energy-dependent attenuation of neutrons

    Science.gov (United States)

    Marleau, Peter

    2015-10-06

    Various technologies pertaining to identifying a material in a sample and imaging the sample are described herein. The material is identified by computing energy-dependent attenuation of neutrons that is caused by presence of the sample in travel paths of the neutrons. A mono-energetic neutron generator emits the neutron, which is downscattered in energy by a first detector unit. The neutron exits the first detector unit and is detected by a second detector unit subsequent to passing through the sample. Energy-dependent attenuation of neutrons passing through the sample is computed based upon a computed energy of the neutron, wherein such energy can be computed based upon 1) known positions of the neutron generator, the first detector unit, and the second detector unit; or 2) computed time of flight of neutrons between the first detector unit and the second detector unit.

  7. Attenuation of vacuum ultraviolet light in liquid argon

    CERN Document Server

    Neumeier, A; Oberauer, L; Potzel, W; Schönert, S; Dandl, T; Heindl, T; Ulrich, A; Wieser, J

    2015-01-01

    The transmission of liquid argon has been measured, wavelength resolved, for a wavelength interval from 118 to 250 nm. The wavelength dependent attenuation length is presented for pure argon. It is shown that no universal wavelength independent attenuation length can be assigned to liquid argon for its own fluorescence light due to the interplay between the wavelength dependent emission and absorption. A decreasing transmission is observed below 130 nm in both chemically cleaned and distilled liquid argon and assigned to absorption by the analogue of the first argon excimer continuum. For not perfectly cleaned argon a strong influence of impurities on the transmission is observed. Two strong absorption bands at 126.5 and 141.0 nm with approximately 2 and 4 nm width, respectively, are assigned to traces of xenon in argon. A broad absorption region below 180 nm is found for unpurified argon and tentatively attributed to the presence of water in the argon sample.

  8. Anatomy of the TAMA SAS seismic attenuation system

    CERN Document Server

    Marka, S; Ando, M; Bertolini, A; Cella, G; DeSalvo, R; Fukushima, M; Iida, Y; Jacquier, F; Kawamura, S; Nishi, Y; Numata, K; Sannibale, V; Somiya, K; Takahashi, R; Tariq, H; Tsubono, K; Ugas, J; Viboud, N; Wang Chen Yang; Yamamoto, H; Yoda, T

    2002-01-01

    The TAMA SAS seismic attenuation system was developed to provide the extremely high level of seismic isolation required by the next generation of interferometric gravitational wave detectors to achieve the desired sensitivity at low frequencies. Our aim was to provide good performance at frequencies above approx 10 Hz, while utilizing only passive subsystems in the sensitive frequency band of the TAMA interferometric gravitational wave detectors. The only active feedback is relegated below 6 Hz and it is used to damp the rigid body resonances of the attenuation chain. Simulations, based on subsystem performance characterizations, indicate that the system can achieve rms mirror residual motion measured in a few tens of nanometres. We will give a brief overview of the subsystems and point out some of the characterization results, supporting our claims of achieved performance. SAS is a passive, UHV compatible and low cost system. It is likely that extremely sensitive experiments in other fields will also profit ...

  9. Signal Attenuation Curve for Different Surface Detector Arrays

    CERN Document Server

    Vicha, J; Nosek, D; Ebr, J

    2014-01-01

    Modern cosmic ray experiments consisting of large array of particle detectors measure the signals of electromagnetic or muon components or their combination. The correction for an amount of atmosphere passed is applied to the surface detector signal before its conversion to the shower energy. Either Monte Carlo based approach assuming certain composition of primaries or indirect estimation using real data and assuming isotropy of arrival directions can be used. Toy surface arrays of different sensitivities to electromagnetic and muon components are assumed in MC simulations to study effects imposed on attenuation curves for varying composition or possible high energy anisotropy. The possible sensitivity of the attenuation curve to the mass composition is also tested for different array types focusing on a future apparatus that can separate muon and electromagnetic component signals.

  10. Anatomy of the TAMA SAS seismic attenuation system

    International Nuclear Information System (INIS)

    The TAMA SAS seismic attenuation system was developed to provide the extremely high level of seismic isolation required by the next generation of interferometric gravitational wave detectors to achieve the desired sensitivity at low frequencies. Our aim was to provide good performance at frequencies above ∼10 Hz, while utilizing only passive subsystems in the sensitive frequency band of the TAMA interferometric gravitational wave detectors. The only active feedback is relegated below 6 Hz and it is used to damp the rigid body resonances of the attenuation chain. Simulations, based on subsystem performance characterizations, indicate that the system can achieve rms mirror residual motion measured in a few tens of nanometres. We will give a brief overview of the subsystems and point out some of the characterization results, supporting our claims of achieved performance. SAS is a passive, UHV compatible and low cost system. It is likely that extremely sensitive experiments in other fields will also profit from our study

  11. Wave Dispersion and Attenuation in Partially Saturated Sandstones

    Institute of Scientific and Technical Information of China (English)

    NIE Jian-Xin; YANG Ding-Hui; YANG Hui-Zhu

    2004-01-01

    @@ We investigate the wave dispersion and attenuation in partially water-saturated sandstones based on the improved Biot/squirt (BISQ) model in which the saturation is introduced. Numerical experiments indicate that the phase velocity of the fast P-wave decreases as the saturation increases in the low-frequency range (102-104 Hz), and reaches the minimum at the full-saturation state. The behaviour of the phase velocity varying with the saturation in the high-frequency range (104-106 Hz), however, is opposite to that in the low-frequency range. The peak value of P-wave attenuation increases with increasing saturation, and is the maximum at the fully saturated state. Numerical models and experiments show that the improved BISQ model is better than the traditional Gassmann-Biot model.

  12. A novel live-attenuated vaccine candidate for mayaro Fever.

    Directory of Open Access Journals (Sweden)

    William J Weise

    2014-08-01

    Full Text Available Mayaro virus (MAYV is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  13. Sustainability of natural attenuation of nitrate in agricultural aquifers

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  14. Design and Simulation of Microwave Attenuators for Superconducting Quantum Devices

    Science.gov (United States)

    Lefebvre, Jay; Yeh, Jen-Hao; Wellstood, Frederick; Palmer, Benjamin

    We have found that dephasing times for quantum superconducting transmons operating nominally at T = 20 mK can be limited by thermal photons in the read-out cavity due to non-equilibrium noise on our input microwave line. In an effort to reduce this noise, we have used finite-element simulations to design attenuators that provide better thermalization of the input microwave signals being delivered to our devices. Our thermal simulations incorporate both electron-phonon decoupling effects due to dissipated power in each element of the attenuator as well as phonon thermal conduction and Kapitza boundary effects. We combine the resulting thermal map with a thermal noise model of each dissipative element of the filter to estimate the effective noise temperature of our filter design.

  15. Is Necessary Attenuation Correction for Cat Brain PET?

    International Nuclear Information System (INIS)

    Photon attenuation and scatter corrections (AC and SC) were necessary for quantification of human PET. However, there is no consensus on whether AC and SC are necessary for the cat brain PET imaging. Since post-injection transmission (TX) PET scans are not permitted or provided to microPET scanner users at present, additional time for performing TX scan and awaiting FDG uptake is required for attenuation and scatter corrections. Increasing probability of subject movement and possible biological effect of long term anesthesia would be the problem in additional TX scan. The aim of this study was to examine the effect of AC and SC for the quantification of cat brain PET data

  16. NATURAL ATTENUATION FOR ECOSYSTEM RESTORATION IN NY/NJ HARBOR

    Energy Technology Data Exchange (ETDEWEB)

    Van der Lelie, D.; Reid-Green, J. D.; Stern, E. A.

    2003-12-31

    We have investigated the feasibility of using natural attenuation methods for ecosystem restoration in New York/New Jersey Harbor. Measurements were made of the most probable number of sulfate-reducing bacteria (SRB) in native sediments and in samples, which had been supplemented with an appropriate electron donor and electron acceptor. The results showed that the activity of the endogenous microbial population in the native sediment was high enough to make possible adequate chemical transformation rates. The bioavailability of the zinc in the sediments was measured using the BIOMET biosensor technique. The bioavailability of the zinc was effectively eliminated following the microbial activities. We concluded that natural attenuation could be used effectively in treating sediments from Newark Bay and surrounding waters and that the resultant materials could likely be used in environmental restoration projects of the type proposed for construction in South Kearny, NJ.

  17. Rapidly rotating neutron star progenitors

    CERN Document Server

    Postnov, K A; Kolesnikov, D A; Popov, S B; Porayko, N K

    2016-01-01

    Rotating proto-neutron stars can be important sources of gravitational waves to be searched for by present-day and future interferometric detectors. It was demonstrated by Imshennik that in extreme cases the rapid rotation of a collapsing stellar core may lead to fission and formation of a binary proto-neutron star which subsequently merges due to gravitational wave emission. In the present paper, we show that such dynamically unstable collapsing stellar cores may be the product of a former merger process of two stellar cores in a common envelope. We applied population synthesis calculations to assess the expected fraction of such rapidly rotating stellar cores which may lead to fission and formation of a pair of proto-neutron stars. We have used the BSE population synthesis code supplemented with a new treatment of stellar core rotation during the evolution via effective core-envelope coupling, characterized by the coupling time, $\\tau_c$. The validity of this approach is checked by direct MESA calculations ...

  18. Rapidly rotating neutron star progenitors

    Science.gov (United States)

    Postnov, K. A.; Kuranov, A. G.; Kolesnikov, D. A.; Popov, S. B.; Porayko, N. K.

    2016-08-01

    Rotating proto-neutron stars can be important sources of gravitational waves to be searched for by present-day and future interferometric detectors. It was demonstrated by Imshennik that in extreme cases the rapid rotation of a collapsing stellar core may lead to fission and formation of a binary proto-neutron star which subsequently merges due to gravitational wave emission. In the present paper, we show that such dynamically unstable collapsing stellar cores may be the product of a former merger process of two stellar cores in a common envelope. We applied population synthesis calculations to assess the expected fraction of such rapidly rotating stellar cores which may lead to fission and formation of a pair of proto-neutron stars. We have used the BSE population synthesis code supplemented with a new treatment of stellar core rotation during the evolution via effective core-envelope coupling, characterized by the coupling time, τc. The validity of this approach is checked by direct MESA calculations of the evolution of a rotating 15 M⊙ star. From comparison of the calculated spin distribution of young neutron stars with the observed one, reported by Popov and Turolla, we infer the value τc ≃ 5 × 105 years. We show that merging of stellar cores in common envelopes can lead to collapses with dynamically unstable proto-neutron stars, with their formation rate being ˜0.1 - 1% of the total core collapses, depending on the common envelope efficiency.

  19. Rapid ISS Power Availability Simulator

    Science.gov (United States)

    Downing, Nicholas

    2011-01-01

    The ISS (International Space Station) Power Resource Officers (PROs) needed a tool to automate the calculation of thousands of ISS power availability simulations used to generate power constraint matrices. Each matrix contains 864 cells, and each cell represents a single power simulation that must be run. The tools available to the flight controllers were very operator intensive and not conducive to rapidly running the thousands of simulations necessary to generate the power constraint data. SOLAR is a Java-based tool that leverages commercial-off-the-shelf software (Satellite Toolkit) and an existing in-house ISS EPS model (SPEED) to rapidly perform thousands of power availability simulations. SOLAR has a very modular architecture and consists of a series of plug-ins that are loosely coupled. The modular architecture of the software allows for the easy replacement of the ISS power system model simulator, re-use of the Satellite Toolkit integration code, and separation of the user interface from the core logic. Satellite Toolkit (STK) is used to generate ISS eclipse and insulation times, solar beta angle, position of the solar arrays over time, and the amount of shadowing on the solar arrays, which is then provided to SPEED to calculate power generation forecasts. The power planning turn-around time is reduced from three months to two weeks (83-percent decrease) using SOLAR, and the amount of PRO power planning support effort is reduced by an estimated 30 percent.

  20. KEPLER RAPIDLY ROTATING GIANT STARS

    Energy Technology Data Exchange (ETDEWEB)

    Costa, A. D.; Martins, B. L. Canto; Bravo, J. P.; Paz-Chinchón, F.; Chagas, M. L. das; Leão, I. C.; Oliveira, G. Pereira de; Silva, R. Rodrigues da; Roque, S.; Oliveira, L. L. A. de; Silva, D. Freire da; De Medeiros, J. R., E-mail: renan@dfte.ufrn.br [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal RN (Brazil)

    2015-07-10

    Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of substellar companions by their hosting stars. In the present Letter, we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time, the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting a very short rotation period with values ranging from 13 to 55 days. This finding points to remarkable surface rotation rates, up to 18 times the rotation of the Sun. These giants are combined with six others recently listed in the literature for mid-infrared (IR) diagnostics based on Wide-field Infrared Survey Explorer information, from which a trend for an IR excess is revealed for at least one-half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

  1. Kepler rapidly rotating giant stars

    CERN Document Server

    Costa, A D; Bravo, J P; Paz-Chinchón, F; Chagas, M L das; Leão, I C; de Oliveira, G Pereira; da Silva, R Rodrigues; Roque, S; de Oliveira, L L A; da Silva, D Freire; De Medeiros, J R

    2015-01-01

    Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of sub-stellar companions by their hosting stars. In the present letter we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting very short rotation period with values ranging from 13 to 55 days. This finding points for remarkable surface rotation rates, up to 18 times the Sun rotation. These giants are combined with 6 other recently listed in the literature for mid-IR diagnostic based on WISE information, from which a trend for an infrared excess is revealed for at least a half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

  2. Rapid self-healing hydrogels

    Science.gov (United States)

    Phadke, Ameya; Zhang, Chao; Arman, Bedri; Hsu, Cheng-Chih; Mashelkar, Raghunath A.; Lele, Ashish K.; Tauber, Michael J.; Arya, Gaurav; Varghese, Shyni

    2012-01-01

    Synthetic materials that are capable of autonomous healing upon damage are being developed at a rapid pace because of their many potential applications. Despite these advancements, achieving self-healing in permanently cross-linked hydrogels has remained elusive because of the presence of water and irreversible cross-links. Here, we demonstrate that permanently cross-linked hydrogels can be engineered to exhibit self-healing in an aqueous environment. We achieve this feature by arming the hydrogel network with flexible-pendant side chains carrying an optimal balance of hydrophilic and hydrophobic moieties that allows the side chains to mediate hydrogen bonds across the hydrogel interfaces with minimal steric hindrance and hydrophobic collapse. The self-healing reported here is rapid, occurring within seconds of the insertion of a crack into the hydrogel or juxtaposition of two separate hydrogel pieces. The healing is reversible and can be switched on and off via changes in pH, allowing external control over the healing process. Moreover, the hydrogels can sustain multiple cycles of healing and separation without compromising their mechanical properties and healing kinetics. Beyond revealing how secondary interactions could be harnessed to introduce new functions to chemically cross-linked polymeric systems, we also demonstrate various potential applications of such easy-to-synthesize, smart, self-healing hydrogels. PMID:22392977

  3. Rapidly Developing Toxic Epidermal Necrolysis

    Directory of Open Access Journals (Sweden)

    Viktoria Oline Barrios Poulsen

    2013-01-01

    Full Text Available Severe cutaneous reactions with potentially fatal outcomes can have many different causes. The Stevens-Johnson syndrome (SJS and toxic epidermal necrolysis (TEN are rare. They are characterized by a low incidence but high mortality, and drugs are most commonly implicated. Urgent active therapy is required. Prompt recognition and withdrawal of suspect drug and rapid intervention can result in favourable outcome. No further international guidelines for treatment exist, and much of the treatment relies on old or experimental concepts with no scientific evidence. We report on a 54-year-old man experiencing rapidly developing drug-induced severe TEN and presented multiorgan failure involving the respiratory and circulatory system, coagulopathy, and renal insufficiency. Detachment counted 30% of total body surface area (TBSA. SCORTEN = 5, indicating a mortality rate >90%. The patient was sedated and mechanically ventilated, supported with fluids and inotropes to maintain a stable circulation. Component therapy was guided by thromboelastography (TEG. The patient received plasmapheresis, and shock reversal treatment was initiated. He was transferred to a specialized intensive care burn unit within 24 hours from admittance. The initial care was continued, and hemodialysis was started. Pulmonary, circulatory, and renal sequelae resolved with intensive care, and re-epithelialization progressed slowly. The patient was discharged home on hospital day 19.

  4. Cognitive, Medical, and Neuroimaging Characteristics of Attenuated Mucopolysaccharidosis Type II

    OpenAIRE

    Yund, Brianna; Rudser, Kyle; Ahmed, Alia; Kovac, Victor; Nestrasil, Igor; Raiman, Julian; Mamak, Eva; Harmatz, Paul; Steiner, Robert; Lau, Heather; Vekaria, Pooja; Wozniak, Jeffrey R.; Lim, Kelvin O.; Delaney, Kathleen; Whitley, Chester

    2014-01-01

    The phenotype of attenuated mucopolysaccharidosis type II (MPS II), also called Hunter syndrome, has not been previously studied in systematic manner. In contrast to the “severe” phenotype, the “attenuated” phenotype does not present with behavioral or cognitive impairment; however the presence of mild behavior and cognitive impairment that might impact long term functional outcomes is unknown. Previously, significant MRI abnormalities have been found in MPS II. Recent evidence suggests white...

  5. Cognitive, Medical, and Neuroimaging Characteristics of Attenuated Mucopolysaccharidosis Type II

    Science.gov (United States)

    Yund, Brianna; Rudser, Kyle; Ahmed, Alia; Kovac, Victor; Nestrasil, Igor; Raiman, Julian; Mamak, Eva; Harmatz, Paul; Steiner, Robert; Lau, Heather; Vekaria, Pooja; Wozniak, Jeffrey R.; Lim, Kelvin O.; Delaney, Kathleen; Whitley, Chester; Shapiro, Elsa G.

    2014-01-01

    The phenotype of attenuated mucopolysaccharidosis type II (MPS II), also called Hunter syndrome, has not been previously studied in systematic manner. In contrast to the “severe” phenotype, the “attenuated” phenotype does not present with behavioral or cognitive impairment; however the presence of mild behavior and cognitive impairment that might impact long term functional outcomes is unknown. Previously, significant MRI abnormalities have been found in MPS II. Recent evidence suggests white matter abnormalities in many MPS disorders. Methods As the initial cross-sectional analysis of a longitudinal study, we studied the association of brain volumes and somatic disease burden with neuropsychological outcomes, including measures of intelligence, memory and attention in 20 patients with attenuated MPS II with a mean age of 15.8. MRI volumes were compared to 55 normal controls. Results While IQ and memory were average, measures of attention were one standard deviation below the average range. Corpus callosum volumes were significantly different from age-matched controls, differing by 22%. Normal age-related volume increases in white matter were not seen in MPS II patients as they were in controls. Somatic disease burden and white matter and corpus callosum volumes were significantly associated with attention deficits. Neither age at evaluation nor age at starting treatment predicted attention outcomes. Conclusions Despite average intelligence, attention is compromised in attenuated MPS II. Results confirm an important role of corpus callosum and cortical white matter abnormality in MPS II as well as the somatic disease burden in contributing to attention difficulties. Awareness by the patient and caregivers with appropriate management and symptomatic support will benefit the attenuated MPS II patient. PMID:25541100

  6. Interlaboratory comparison of radiation-induced attenuation in optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Friebele, E.J.; Lyons, P.B.; Blackburn, J.C.; Henschel, H.; Johan, A.; Krinsky, J.A.; Robinson, A.; Schneider, W.; Smith, D.; Taylor, E.W. (Naval Research Lab., Washington, DC (USA); Los Alamos National Lab., NM (USA); Harry Diamond Labs., Adelphi, MD (USA); Fraunhofer-Institut fuer Naturwissenschaftlich-Technische Trendanalysen (INT), Euskirchen (Germany, F.R.); Direction des Recherches, Etudes et Techni

    1989-08-01

    A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10{sup -9} to 10{sup 1} s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs.

  7. Wave attenuation in partially filled unsteady pipe flow

    OpenAIRE

    Abd El-Baky Mohamed, Nagwa

    1989-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. Much research activity is carried out to reduce water consumption for domestic purposes. This leads to the possibility of reducing the amount of water introduced into building drainage systems. However, an accurate estimation of the flow attenuation within building drainage pipes is of great importance to prevent solid eposition and subsequent blockage. The research is focused on the fiel...

  8. Advanced reconstruction of attenuation maps using SPECT emission data only

    Science.gov (United States)

    Salomon, André; Goedicke, Andreas; Aach, Til

    2009-02-01

    Today, attenuation corrected SPECT, typically performed using CT or Gadolinium line source based transmission scans, is more and more becoming standard in many medical applications. Moreover, the information about the material density distribution provided by these scans is key for other artifact compensation approaches in advanced SPECT reconstruction. Major drawbacks of these approaches are the additional patient radiation and hardware/maintenance costs as well as the additional workflow effort, e.g. if the CT scans are not performed on a hybrid scanner. It has been investigated in the past, whether it is possible to recover this structural information solely from the SPECT scan data. However, the investigated methods often result in noticeable image artifacts due to cross-dependences between attenuation and activity distribution estimation. With the simultaneous reconstruction method presented in this paper, we aim to effectively prevent these typical cross-talk artifacts using a-priori known atlas information of a human body. At first, an initial 3D shape model is coarsely registered to the SPECT data using anatomical landmarks and each organ structure within the model is identified with its typical attenuation coefficient. During the iterative reconstruction based on a modified ML-EM scheme, the algorithm simultaneously adapts both, the local activity estimation and the 3D shape model in order to improve the overall consistency between measured and estimated sinogram data. By explicitly avoiding topology modifications resulting in a non-anatomical state, we ensure that the estimated attenuation map remains realistic. Several tests with simulated as well as real patient SPECT data were performed to test the proposed algorithm, which demonstrated reliable convergence behaviour in both cases. Comparing the achieved results with available reference data, an overall good agreement for both cold as well as hot activity regions could be observed (mean deviation: -5.98%).

  9. Enhancing lysosome biogenesis attenuates BNIP3-induced cardiomyocyte death

    OpenAIRE

    Ma, Xiucui; Godar, Rebecca J.; Liu, Haiyan; Diwan, Abhinav

    2012-01-01

    Hypoxia-inducible pro-death protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3), provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of autophagy accelerates BNIP3-induced cell death, by preventing removal of damaged mitochondria. We tested the hypothesis that stimulating autophagy will attenuate BNIP3-induced cardiomyocyte death. Neonatal rat cardiac myocytes (NRCMs) were adenovirally transduced with BNIP3 (or LacZ as c...

  10. Working Memory Load Attenuates Emotional Enhancement in Recognition Memory

    OpenAIRE

    Ewa Aurelia Miendlarzewska; Gijs eVan Elswijk; Carlo Vittorio Cannistraci; Raymond evan Ee

    2013-01-01

    Emotionally arousing stimuli are perceived and remembered better than neutral stimuli. Under threat, this negativity bias is further increased. We investigated whether working memory load can attenuate incidental memory for emotional images. Two groups of participants performed the N-back task with two working memory load levels. In one group, we induced anxiety using a threat-of-shock paradigm to increase attentional processing of negative information. During task performance we incidentally...

  11. Effects of impurities on particle sizing by acoustic attenuation spectroscopy

    OpenAIRE

    Inam, Muhammad Asif; Frances, Christine

    2010-01-01

    It is important to have correct information regarding particle size in order to interpret, control, and optimize many industrial processes. Prior to the recent advent of acoustic attenuation spectroscopy, it was difficult to study particle size distribution online and under real process conditions in processes involving concentrated dispersions (suspensions or emulsions). The technique still needs improvement because it is less known how and under which conditions to employ the technique when...

  12. Arsenic cycling in hydrocarbon plumes: secondary effects of natural attenuation

    Science.gov (United States)

    Cozzarelli, Isabelle M.; Schreiber, Madeline E.; Erickson, Melinda L.; Ziegler, Brady A.

    2016-01-01

    Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

  13. Acetazolamide Attenuates Lithium-Induced Nephrogenic Diabetes Insipidus.

    Science.gov (United States)

    de Groot, Theun; Sinke, Anne P; Kortenoeven, Marleen L A; Alsady, Mohammad; Baumgarten, Ruben; Devuyst, Olivier; Loffing, Johannes; Wetzels, Jack F; Deen, Peter M T

    2016-07-01

    To reduce lithium-induced nephrogenic diabetes insipidus (lithium-NDI), patients with bipolar disorder are treated with thiazide and amiloride, which are thought to induce antidiuresis by a compensatory increase in prourine uptake in proximal tubules. However, thiazides induced antidiuresis and alkalinized the urine in lithium-NDI mice lacking the sodium-chloride cotransporter, suggesting that inhibition of carbonic anhydrases (CAs) confers the beneficial thiazide effect. Therefore, we tested the effect of the CA-specific blocker acetazolamide in lithium-NDI. In collecting duct (mpkCCD) cells, acetazolamide reduced the cellular lithium content and attenuated lithium-induced downregulation of aquaporin-2 through a mechanism different from that of amiloride. Treatment of lithium-NDI mice with acetazolamide or thiazide/amiloride induced similar antidiuresis and increased urine osmolality and aquaporin-2 abundance. Thiazide/amiloride-treated mice showed hyponatremia, hyperkalemia, hypercalcemia, metabolic acidosis, and increased serum lithium concentrations, adverse effects previously observed in patients but not in acetazolamide-treated mice in this study. Furthermore, acetazolamide treatment reduced inulin clearance and cortical expression of sodium/hydrogen exchanger 3 and attenuated the increased expression of urinary PGE2 observed in lithium-NDI mice. These results show that the antidiuresis with acetazolamide was partially caused by a tubular-glomerular feedback response and reduced GFR. The tubular-glomerular feedback response and/or direct effect on collecting duct principal or intercalated cells may underlie the reduced urinary PGE2 levels with acetazolamide, thereby contributing to the attenuation of lithium-NDI. In conclusion, CA activity contributes to lithium-NDI development, and acetazolamide attenuates lithium-NDI development in mice similar to thiazide/amiloride but with fewer adverse effects.

  14. Attenuation Analysis and Acoustic Pressure Levels for Combined Absorptive Mufflers

    Directory of Open Access Journals (Sweden)

    Ovidiu Vasile

    2011-09-01

    Full Text Available The paper describes the pressure-wave propagation in a muffler for an internal combustion engine in case of two combined mufflers geometry. The approach is generally applicable to analyzing the damping of propagation of harmonic pressure waves. The paper purpose is to show finite elements analysis of both inductive and resistive damping in pressure acoustics. The main output is the attenuation and acoustic pressure levels for the frequency range 50 Hz–3000 Hz.

  15. The Attribute for Hydrocarbon Prediction Based on Attenuation

    Science.gov (United States)

    Hermana, Maman; Harith, Z. Z. T.; Sum, C. W.; Ghosh, D. P.

    2014-03-01

    Hydrocarbon prediction is a crucial issue in the oil and gas industry. Currently, the prediction of pore fluid and lithology are based on amplitude interpretation which has the potential to produce pitfalls in certain conditions of reservoir. Motivated by this fact, this work is directed to find out other attributes that can be used to reduce the pitfalls in the amplitude interpretation. Some seismic attributes were examined and studies showed that the attenuation attribute is a better attribute for hydrocarbon prediction. Theoretically, the attenuation mechanism of wave propagation is associated with the movement of fluid in the pore; hence the existence of hydrocarbon in the pore will be represented by attenuation attribute directly. In this paper we evaluated the feasibility of the quality factor ratio of P-wave and S-wave (Qp/Qs) as hydrocarbon indicator using well data and also we developed a new attribute based on attenuation for hydrocarbon prediction -- Normalized Energy Reduction Stack (NERS). To achieve these goals, this work was divided into 3 main parts; estimating the Qp/Qs on well log data, testing the new attribute in the synthetic data and applying the new attribute on real data in Malay Basin data. The result show that the Qp/Qs is better than Poisson's ratio and Lamda over Mu as hydrocarbon indicator. The curve, trend analysis and contrast of Qp/Qs is more powerful at distinguishing pore fluid than Poisson ratio and Lamda over Mu. The NERS attribute was successful in distinguishing the hydrocarbon from brine on synthetic data. Applying this attribute on real data on Malay basin, the NERS attribute is qualitatively conformable with the structure and location where the gas is predicted. The quantitative interpretation of this attribute for hydrocarbon prediction needs to be investigated further.

  16. Extragalactic Background Light and Gamma-Ray Attenuation

    OpenAIRE

    Primack, Joel R.; Dominguez, Alberto; Gilmore, Rudy C.; Somerville, Rachel S.

    2011-01-01

    Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits from observed galaxies. These upper limits now rule out some EBL models and purported observations, with improved data likely to provide even stronger constraints. We present EBL calculations both based on multiwavelength observations of thousands of galaxie...

  17. Fluvoxamine Attenuated Endoplasmic Reticulum Stress-Induced Leptin Resistance

    OpenAIRE

    Hosoi, Toru; Miyahara, Tsuyoshi; Kayano, Takaaki; Yokoyama, Shota; Ozawa, Koichiro

    2012-01-01

    Increasing evidence indicates that endoplasmic reticulum stress (ER stress) is involved in the development of metabolic syndrome. However, pharmacological treatments targeting ER stress are not well understood. In the present study, we found that fluvoxamine, a selective serotonin reuptake inhibitor used for depression, can attenuate ER stress-induced “leptin resistance,” i.e., insensitivity to the anti-obesity hormone leptin. Treatment with tunicamycin, an ER stress-inducing reagent, caused ...

  18. Reactogenicity to a Live Attenuated Varicella Vaccine in Canadian Children

    OpenAIRE

    Diaz-Mitoma, Francisco; Halperin, Scott A.; Scheifele, David

    2000-01-01

    OBJECTIVE: To assess the reactogenicity and safety of a thermostable, high titre, varicella vaccine in healthy infants and children.DESIGN: Open study of 505 children monitored for 42 days after vaccination.SETTING: Three urban Canadian centres (Halifax, Ottawa and Vancouver).PARTICIPANTS: 505 healthy children one to 12 years of age were enrolled and 504 completed the study. All were susceptible to varicella by history.INTERVENTIONS: All participants received one dose of live attenuated varic...

  19. Cathepsin B inactivation attenuates hepatic injury and fibrosis during cholestasis

    OpenAIRE

    Canbay, Ali; Guicciardi, Maria Eugenia; Higuchi, Hajime; Feldstein, Ariel; Bronk, Steven F.; Rydzewski, Robert; Tanai, Makiko; Gores, Gregory J.

    2004-01-01

    Although a lysosomal, cathepsin B–dependent (Ctsb-dependent) pathway of apoptosis has been described, the contribution of this pathway to tissue damage remains unclear. Our aim was to ascertain if Ctsb inactivation attenuates liver injury, inflammation, and fibrogenesis after bile duct ligation (BDL). In 3-day BDL mice, hepatocyte apoptosis, mitochondrial cytochrome c release, and serum alanine aminotransferase (ALT) values were reduced in Ctsb–/– versus Ctsb+/+ animals. Likewise, R-3032 (a C...

  20. Clarithromycin attenuates mastectomy-induced acute inflammatory response

    OpenAIRE

    Chow, Louis W. C.; Yuen, Kwok-Yung; Woo, Patrick C. Y.; Wei, William I.

    2000-01-01

    Based on the observation that administration of clarithromycin led to an attenuation of the inflammatory response induced by surgical trauma in a guinea pig model, we investigated the potential beneficial effects of clarithromycin on the local and systemic inflammatory response in patients undergoing mastectomy in an open-label prospective study. During a 16-month period, 54 patients who underwent mastectomy were randomly divided into two groups. In one group, the patients received oral clari...

  1. Poliovirus tropism and attenuation are determined after internal ribosome entry

    OpenAIRE

    Kauder, Steven E.; Racaniello, Vincent R

    2004-01-01

    Poliovirus replication is limited to a few organs, including the brain and spinal cord. This restricted tropism may be a consequence of organ-specific differences in translation initiation by the poliovirus internal ribosome entry site (IRES). A C-to-U mutation at base 472 in the IRES of the Sabin type 3 poliovirus vaccine strain, known to attenuate neurovirulence, may further restrict tropism by eliminating viral replication in the CNS. To determine the relationship between IRES-mediated tra...

  2. Simvastatin attenuates ventilator-induced lung injury in mice

    OpenAIRE

    Müller, Holger C; Hellwig, Katharina; Rosseau, Simone; Tschernig, Thomas; Schmiedl, Andreas; Gutbier, Birgitt; Schmeck, Bernd; Hippenstiel, Stefan; Peters, Harm; Morawietz, Lars; Suttorp, Norbert; Witzenrath, Martin

    2010-01-01

    Introduction Mechanical ventilation (MV) is a life saving intervention in acute respiratory failure without alternative. However, particularly in pre-injured lungs, even protective ventilation strategies may evoke ventilator-induced lung injury (VILI), which is characterized by pulmonary inflammation and vascular leakage. Adjuvant pharmacologic strategies in addition to lung protective ventilation to attenuate VILI are lacking. Simvastatin exhibited anti-inflammatory and endothelial barrier s...

  3. Cardiotoxin III suppresses MDA-MB-231 cell metastasis through the inhibition of EGF/EGFR-mediated signaling pathway.

    Science.gov (United States)

    Tsai, Pei-Chien; Hsieh, Chi-Ying; Chiu, Chien-Chih; Wang, Chih-Kuang; Chang, Long-Sen; Lin, Shinne-Ren

    2012-10-01

    Cardiotoxin III (CTX III), a basic polypeptide isolated from Naja naja atra venom, has been shown to exhibit anticancer activity. Epidermal growth factor (EGF) and its receptor, EGFR, play roles in cancer metastasis in various tumors. We use EGF as a metastatic inducer of MDA-MB-231 cells to investigate the effect of CTX III on cell migration. CTX III inhibited the EGF-induced activation of matrix metalloproteinase-9 (MMP-9), and further suppressed cell invasion and migration without obvious cellular cytotoxicity. CTX III suppressed EGF-induced nuclear factor-kappaB (NF-κB) nuclear translocation and also abrogated the EGF-induced phosphorylation of EGFR, phosphatidylinositol 3-kinase (PI3K)/Akt, and extracellular regulated kinase (ERK)1/2. In addition, CTX III similar to wortmannin (a PI3K inhibitor) and U0126 (an up-stream kinase regulating ERK1/2 inhibitor) attenuated cell migration and invasion induced by EGF. Furthermore, the EGFR inhibitor AG1478 inhibited EGF-induced MMP-9 expression, cell migration and invasion, as well as the activation of ERK1/2 and PI3K/Akt, suggesting that ERK1/2 and PI3K/Akt activation occur downstream of EGFR activation. These findings suggest that CTX III inhibited the EGF-induced invasion and migration of MDA-MB-231 cells via EGFR-dependent PI3K/Akt, ERK1/2, and NF-κB signaling, leading to the down-regulation of MMP-9 expression. These results provide a novel mechanism to explain the role of CTX III as a potent anti-metastatic agent in MDA-MB-231 cells.

  4. Creating a collimated ultrasound beam in highly attenuating fluids.

    Science.gov (United States)

    Raeymaekers, Bart; Pantea, Cristian; Sinha, Dipen N

    2012-04-01

    We have devised a method, based on a parametric array concept, to create a low-frequency (300-500 kHz) collimated ultrasound beam in fluids highly attenuating to sound. This collimated beam serves as the basis for designing an ultrasound visualization system that can be used in the oil exploration industry for down-hole imaging in drilling fluids. We present the results of two different approaches to generating a collimated beam in three types of highly attenuating drilling mud. In the first approach, the drilling mud itself was used as a nonlinear mixing medium to create a parametric array. However, the short absorption length in mud limits the mixing length and, consequently, the resulting beam is weak and broad. In the second improved approach, the beam generation process was confined to a separate "frequency mixing tube" that contained an acoustically non-linear, low attenuation medium (e.g., water) that allowed establishing a usable parametric array in the mixing tube. A low-frequency collimated beam was thus created prior to its propagation into the drilling fluid. Using the latter technique, the penetration depth of the low frequency ultrasound beam in the drilling fluid was significantly extended. We also present measurements of acoustic nonlinearity in various types of drilling mud. PMID:22204917

  5. Attenuation of S wave in the crust of Ordos massif

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-gui; CHUO Yong-qing; CHEN Shu-qing; JIN Chun-hua

    2005-01-01

    We presented attenuation characteristics of S waves in the crust of Ordos massif. Using 487 pieces of digital oscillograms of 19 seismic events recorded by 32 seismologic stations located on Ordos massif and its surroundings, we have calculated the parameter of three-segment geometric attenuation and give the relation of inelastic attenuation Q value with frequency in the crust of Ordos massif, site responses of 32 stations, and source parameters of 19 events by the genetic algorithm. The results indicate that Q value (at 1 Hz) of S-wave in the crust of Ordos massif is much larger than that in the geologically active tectonic region. The site responses of the 32 stations in the high-frequency section do not show clear amplification effect except one or two stations, while in the low-frequency section, there is difference among the stations. The logarithmic value of seismic moment and the magnitude ML of 19 seismic events has a very good linear relationship.

  6. Dust Attenuation in High Redshift Galaxies -- 'Diamonds in the Sky'

    CERN Document Server

    Scoville, Nick; Capak, Peter; Kakazu, Yuko; Li, Gongjie; Steinhardt, Charles

    2014-01-01

    We use observed optical to near infrared spectral energy distributions (SEDs) of 266 galaxies in the COSMOS survey to derive the wavelength dependence of the dust attenuation at high redshift. All of the galaxies have spectroscopic redshifts in the range z = 2 to 6.5. The presence of the CIV absorption feature, indicating that the rest-frame UV-optical SED is dominated by OB stars, is used to select objects for which the intrinsic, unattenuated spectrum has a well-established shape. Comparison of this intrinsic spectrum with the observed broadband photometric SED then permits derivation of the wavelength dependence of the dust attenuation. The derived dust attenuation curve is similar in overall shape to the Calzetti curve for local starburst galaxies. We also see the 2175 \\AA~bump feature which is present in the Milky Way and LMC extinction curves but not seen in the Calzetti curve. The bump feature is commonly attributed to graphite or PAHs. No significant dependence is seen with redshift between sub-sample...

  7. An adaptive noise attenuation method for edge and amplitude preservation

    Institute of Scientific and Technical Information of China (English)

    Cai Han-Peng; He Zhen-Hua; Li Ya-Lin; He Guang-Ming; Zou Wen; Zhang Dong-Jun; Liu Pu

    2014-01-01

    Noise intensity distributed in seismic data varies with different frequencies or frequency bands; thus, noise attenuation on the full-frequency band affects the dynamic properties of the seismic reflection signal and the subsequent seismic data interpretation, reservoir description, hydrocarbon detection, etc. Hence, we propose an adaptive noise attenuation method for edge and amplitude preservation, wherein the wavelet packet transform is used to decompose the full-band seismic signal into multiband data and then process these data using nonlinear anisotropic dip-oriented edge-preservingfi ltering. In the fi ltering, the calculated diffusion tensor from the structure tensor can be exploited to establish the direction of smoothing. In addition, the fault confidence measure and discontinuity operator can be used to preserve the structural and stratigraphic discontinuities and edges, and the decorrelation criteria can be used to establish the number of iterations. These parameters can minimize the intervention and subjectivity of the interpreter, and simplify the application of the proposed method. We applied the proposed method to synthetic and real 3D marine seismic data. We found that the proposed method could be used to attenuate noise in seismic data while preserving the effective discontinuity information and amplitude characteristics in seismic refl ection waves, providing high-quality data for interpretation and analysis such as high-resolution processing, attribute analysis, and inversion.

  8. Simulating atmospheric free-space optical propagation: rainfall attenuation

    Science.gov (United States)

    Achour, Maha

    2002-04-01

    With recent advances and interest in Free-Space Optics (FSO) for commercial deployments, more attention has been placed on FSO weather effects and the availability of global weather databases. The Meteorological Visual Range (Visibility) is considered one of the main weather parameters necessary to estimate FSO attenuation due to haze, fog and low clouds. Proper understanding of visibility measurements conducted throughout the years is essential. Unfortunately, such information is missing from most of the databases, leaving FSO players no choice but to use the standard visibility equation based on 2% contrast and other assumptions on the source luminance and its background. Another challenge is that visibility is measured using the visual wavelength of 550 nm. Extrapolating the measured attenuations to longer infrared wavelengths is not trivial and involves extensive experimentations. Scattering of electromagnetic waves by spherical droplets of different sizes is considered to simulate FSO scattering effects. This paper serves as an introduction to a series of publications regarding simulation of FSO atmospheric propagation. This first part focuses on attenuation due to rainfall. Additional weather parameters, such as rainfall rate, temperature and relative humidity are considered to effectively build the rain model. Comparison with already published experimental measurement is performed to validate the model. The scattering cross section due to rain is derived from the density of different raindrop sizes and the raindrops fall velocity is derived from the overall rainfall rate. Absorption due the presence of water vapor is computed using the temperature and relative humidity measurements.

  9. Clinical evaluation strategies for a live attenuated tetravalent dengue vaccine.

    Science.gov (United States)

    Precioso, Alexander Roberto; Palacios, Ricardo; Thomé, Beatriz; Mondini, Gabriella; Braga, Patrícia; Kalil, Jorge

    2015-12-10

    Butantan Institute is a public Brazilian biomedical research-manufacturer center affiliated to the São Paulo State Secretary of Health. Currently, Butantan is one of the main public producers of vaccines, antivenoms, and antitoxins in Latin America. The partnership between Butantan and the National Institutes of Health (NIH) of the United Sates has been one of the longest and most successful partnerships in the development and manufacturing of new vaccines. Recently, Butantan Institute has developed and manufactured a lyophilized tetravalent live attenuated dengue vaccine with the four dengue viruses attenuated and licensed from the Laboratory of Infectious Diseases at The National Institutes of Allergy and Infectious Diseases (LID/NIAID/NIH). The objective of this paper is to describe the clinical evaluation strategies of a live attenuated tetravalent dengue vaccine (Butantan-DV) developed and manufactured by Butantan Institute. These clinical strategies will be used to evaluate the Butantan-DV Phase III trial to support the Butantan-DV licensure for protection against any symptomatic dengue caused by any serotype in people aged 2 to 59 years.

  10. Ultrasound attenuation as a quantitative measure of fracture healing

    Science.gov (United States)

    Gheduzzi, Sabina; Humphrey, Victor F.; Dodd, Simon P.; Cunningham, James L.; Miles, Anthony W.

    2004-10-01

    The monitoring of fracture healing still relies upon the judgment of callus formation and on the manual assessment of the stiffness of the fracture. A diagnostic tool capable of quantitatively measuring healing progression of a fracture would allow the fine-tuning of the treatment regime. Ultrasound attenuation measurements were adopted as a possible method of assessing the healing process in human long bones. The method involves exciting ultrasonic waves at 200 kHz in the bone and measuring the reradiation along the bone and across the fracture zone. Seven cadaveric femora were tested in vitro in intact form and after creating a transverse fracture by sawing through the cortex. The effects of five different fracture types were investigated. A partial fracture, corresponding to a 50% cut through the cortex, a closed fracture, and fractures of widths varying between 1, 2, and 4 mm were investigated. The introduction of a fracture was found to produce a dramatic effect on the amplitude of the signal. Ultrasound attenuation was found to be sensitive to the presence of a fracture, even when the fracture was well reduced. It would therefore appear feasible to adopt attenuation across a fracture as a quantitative measurement of fracture healing.

  11. Gender differences in real-world hearing protector attenuation.

    Science.gov (United States)

    Abel, S M; Alberti, P W; Rokas, D

    1988-04-01

    This research investigated the possibility of differences in real-world attenuation attributable to gender. A total of 160 subjects, 80 males and 80 females, under the age of 45 years, and with normal hearing, were tested. Subjects were assigned to four hearing protector categories with the restriction that there were 20 males and 20 females in each group. The devices chosen for study were the E-A-R expandable foam plug, the Willson Sound Silencer premolded vinyl plug with double flange, the Bilsom Soft polyethylene encapsulated glass fiber plug, and the MSA Ear Defender (V-51R) premolded vinyl plug with single flange. Binaural headphone detection thresholds were measured in quiet with the open ear, and subsequently with protectors fitted binaurally for one-third octave noise bands centered at 250, 500, 1000, 3150 and 6300 Hz. The results indicated that attenuation scores achieved by females were less than those observed for males when the device was sold in only one size. Apart from the question of adequate sizing, for two of the insert protectors studied, mean achieved attenuation fell short of the manufacturer's specifications by as much as 18 dB, for particular frequencies tested. The relatively wide variation in scores observed for all four protectors in spite of experimenter-fit could not be accounted for by differences in either hearing threshold across subjects or by size of plug fit, for those devices available in several sizes.

  12. GPR data noise attenuation on the curvelet transform

    Institute of Scientific and Technical Information of China (English)

    Bao Qian-Zong; Li Qing-Chun; Chen Wen-Chao

    2014-01-01

    Signal extraction is critical in GRP data processing and noise attenuation. When the target depth is shallow, its refl ection echo signal will overlap with the background noise, affecting the detection of arrival time and localization of the target. Thus, we propose a noise attenuation method based on the curvelet transform. First, the original signal is transformed into the curvelet domain, and then the curvelet coefficients of the background noise are extracted according to the distribution features that differ from the effective signal. In the curvelet domain, the coarse-scale curvelet atom is isotropic. Hence, a two-dimensional directional filter is designed to estimate the high-energy background noise in the coarse-scale domain, and then, attenuate the background noise and highlight the effective signal. In this process, we also use a subscale threshold value of the curvelet domain tofi lter out random noise. Finally, we compare the proposed method with the average elimination and 2D continuous wavelet transform methods. The results show that the proposed method not only removes the background noise but also eliminates the coherent interference and random noise. The numerical simulation and the real data application suggest and verify the feasibility and effectiveness of the proposed method.

  13. Multicomponent seismic noise attenuation with multivariate order statistic filters

    Science.gov (United States)

    Wang, Chao; Wang, Yun; Wang, Xiaokai; Xun, Chao

    2016-10-01

    The vector relationship between multicomponent seismic data is highly important for multicomponent processing and interpretation, but this vector relationship could be damaged when each component is processed individually. To overcome the drawback of standard component-by-component filtering, multivariate order statistic filters are introduced and extended to attenuate the noise of multicomponent seismic data by treating such dataset as a vector wavefield rather than a set of scalar fields. According to the characteristics of seismic signals, we implement this type of multivariate filtering along local events. First, the optimal local events are recognized according to the similarity between the vector signals which are windowed from neighbouring seismic traces with a sliding time window along each trial trajectory. An efficient strategy is used to reduce the computational cost of similarity measurement for vector signals. Next, one vector sample each from the neighbouring traces are extracted along the optimal local event as the input data for a multivariate filter. Different multivariate filters are optimal for different noise. The multichannel modified trimmed mean (MTM) filter, as one of the multivariate order statistic filters, is applied to synthetic and field multicomponent seismic data to test its performance for attenuating white Gaussian noise. The results indicate that the multichannel MTM filter can attenuate noise while preserving the relative amplitude information of multicomponent seismic data more effectively than a single-channel filter.

  14. Attenuation Tomography of Sierra Negra Volcano of the Galapagos Archipelago

    Science.gov (United States)

    Rodd, R.; Lees, J. M.

    2014-12-01

    Following relocation of events with the double-difference location algorithm (HypoDD), we apply tomographic methods to extract 3D attenuation models illuminating the plumbing system of the Sierra Negra Caldera of the Galapagos Archipelago. The dataset consists of 1737 events recorded from July 2009 to June 2011 on the 17-station SIGNET broadband seismic array. We use t* spectral decay methods for both P- and S- phases with the clustered locations to highlight locations where significant variations in Q suggest the presence of magma melt. While the presence of a magma sill, at least 2 km depth, is indicated by InSAR and GPS studies, the delineated magma body has not been explored in detail. The lower bound of the proposed magma accumulation is still under question and thus forms the primary target of this research. Melt replenishment and degassing of the magma sill is believed to cause inflation and/or deflation of the caldera floor. Imaging the extent of the magma sill will provide insight into the feeder system and deformation process of the Sierra Negra caldera. Detailed relocation, Qp and Qs inversion, as well as estimates of the scattering attenuation using coda-normalization technique will be presented. The close relationship between seismic attenuation and the thermal state of the magmatic system suggests we can distinguish melt and/or fluid regions within the Sierra Negra plumbing system.

  15. Adaptation with disturbance attenuation in nonlinear control systems

    Energy Technology Data Exchange (ETDEWEB)

    Basar, T. [Univ. of Illinois, Urbana, IL (United States)

    1997-12-31

    We present an optimization-based adaptive controller design for nonlinear systems exhibiting parametric as well as functional uncertainty. The approach involves the formulation of an appropriate cost functional that places positive weight on deviations from the achievement of desired objectives (such as tracking of a reference trajectory while the system exhibits good transient performance) and negative weight on the energy of the uncertainty. This cost functional also translates into a disturbance attenuation inequality which quantifies the effect of the presence of uncertainty on the desired objective, which in turn yields an interpretation for the optimizing control as one that optimally attenuates the disturbance, viewed as the collection of unknown parameters and unknown signals entering the system dynamics. In addition to this disturbance attenuation property, the controllers obtained also feature adaptation in the sense that they help with identification of the unknown parameters, even though this has not been set as the primary goal of the design. In spite of this adaptation/identification role, the controllers obtained are not of certainty-equivalent type, which means that the identification and the control phases of the design are not decoupled.

  16. Plasmodium yoelii: induction of attenuated mutants by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Waki, S.; Yonome, I.; Suzuki, M.

    1986-12-01

    When erythrocytic forms of Plasmodium yoelii nigeriensis, which is invariably fatal in mice, were exposed to X rays, the dose to reduce surviving parasites to one millionth was 100 gray (10 Krad). A suspension of 5 X 10(6) per ml of parasitized erythrocyte was irradiated at 100 gray, and 0.2 ml aliquots were inoculated into 22 mice. Eleven mice showed patent parasitemia, and in these the growth curves were less steep than that found in nonirradiated parasites. The infections of 8 mice of the 11 were self-resolving, and the attenuated feature of the parasites maintained following a limited number of blood passages. The parasites were slowly growing even in nude mice and cause self-resolving infections in intact mice. BALB/c mice immunized with the attenuated parasites were protected against subsequent challenge infections with the original virulent erythrocytic and sporogonic forms. These findings indicate that attenuated mutants of malaria parasites can be readily induced by this method.

  17. Heavy weight concrete with special mixes for neutron attenuation

    International Nuclear Information System (INIS)

    This work is concerned with the study of the attenuation properties of special mixes of magnetite concrete for fast and thermal neutrons. Investigations were carried out using a collimated beam of neutrons emitted from Pu-α-Be and Californium-252 neutron sources. The fast spectra of neutrons were measured by a scintillation spectrometer with stilbene crystal. Discrimination against undesired pulses of neutrons or gamma -rays was achieved by a zero crossover method. The thermal neutron fluxes were measured by a BF3 detector. The obtained data are displayed in the form of spectra for fast neutrons and attenuation relations for thermal neutrons.The thermal neutron fluxes were measured using bare beam and beams filtered by 113 Cd and B4 C filters to discuss the origin of thermal neutrons interacting with the concrete samples. The obtained results were also used to derive the attenuation coefficients for total thermal neutrons and for newly produced thermal neutrons resulting from neutron beams filtered by 113 Cd and B4 C in the different magnetite concrete shields of different thicknesses.

  18. Comparison of Reg. Guide 1.99 fluence attenuation methods

    Energy Technology Data Exchange (ETDEWEB)

    Jones, E.N. [TransWare Enterprises Inc., 1565 Mediterranean Dr., Sycamore, IL 60178 (United States)

    2011-07-01

    U.S. Regulatory Guide 1.99 Revision 2 (U.S. Nuclear Regulatory Commission, 1988, 'Radiation Embrittlement of Reactor Vessel Materials,' Regulatory Guide 1.99, Revision 2, Washington, D.C.) provides for the use of two substantially different methods for determining through-wall fluence in nuclear reactor pressure vessels. One method is a generic attenuation curve based on a simplistic exponential decay equation. Partly due to the simplicity of its application, the generic attenuation method is predominantly used for licensing calculations. However, it has a limitation in that at increasing distances away from the core belt-line, it becomes increasingly less accurate because it cannot account for neutron streaming effects in the cavity region surrounding the pressure vessel. The other attenuation method is based on a displacement per atom (dpa) calculation specific to the reactor vessel structure. The dpa method provides a more accurate representation of fluence attenuation through the reactor pressure vessel (RPV) wall at all elevations of the pressure vessel because it does account for neutron streaming in the cavity region. A requirement for using the dpa method, however, is an accurate flux solution through the RPV wall. This requirement has limited the use of traditional transport methods, such as discrete ordinates, that are limited by their treatment of cavity regions (i.e., air) outside the pressure vessel wall. TransWare Enterprises, under the sponsorship of EPRI and BWRVIR has developed an advanced three-dimensional transport methodology capable of producing fully converged flux solutions throughout the entire reactor system, including in the cavity region and primary shield structures. This methodology provides an accurate and reliable determination of through-wall fluence in boiling water reactor (BWR) and pressurized water reactor (PWR) pressure vessels, thus allowing the dpa method to be implemented with high reliability. Using this advanced 3

  19. Forward- vs. Inverse Problems in Modeling Seismic Attenuation

    Science.gov (United States)

    Morozov, I. B.

    2015-12-01

    Seismic attenuation is an important property of wave propagation used in numerous applications. However, the attenuation is also a complex phenomenon, and it is important to differentiate between its two typical uses: 1) in forward problems, to model the amplitudes and spectral contents of waves required for hazard assessment and geotechnical engineering, and 2) in inverse problems, to determine the physical properties of the subsurface. In the forward-problem sense, the attenuation is successfully characterized in terms of empirical parameters of geometric spreading, radiation patterns, scattering amplitudes, t-star, alpha, kappa, or Q. Arguably, the predicted energy losses can be correct even if the underlying attenuation model is phenomenological and not sufficiently based on physics. An example of such phenomenological model is the viscoelasticity based on the correspondence principle and the Q-factor assigned to the material. By contrast, when used to invert for in situ material properties, models addressing the specific physics are required. In many studies (including in this session), a Q-factor is interpreted as a property of a point within the subsurface; however this property is only phenomenological and may be physically insufficient or inconsistent. For example, the bulk or shear Q at the same point can be different when evaluated from different wave modes. The cases of frequency-dependent Q are particularly prone of ambiguities such as trade-off with the assumed background geometric spreading. To rigorously characterize the in situ material properties responsible for seismic-wave attenuation, it is insufficient to only focus on the seismic energy loss. Mechanical models of the material need to be considered. Such models can be constructed by using Lagrangian mechanics. These models should likely contain no Q but will be based on parameters of microstructure such as heterogeneity, fractures, or fluids. I illustrate several such models based on viscosity

  20. Polymerase Mechanism-Based Method of Viral Attenuation

    Science.gov (United States)

    Lee, Cheri A.; August, Avery; Arnold, Jamie J.; Cameron, Craig E.

    2016-01-01

    Vaccines remain the most effective way of preventing infection and spread of infectious diseases. These prophylactics have been used for centuries but still to this day only three main design strategies exist: (1) live attenuated virus (LAV) vaccines, (2) killed or inactivated virus vaccines, (3) and subunit vaccines of the three, the most efficacious vaccines remain LAVs. LAVs replicate in relevant tissues, elicit strong cellular and humoral responses, and often confer lifelong immunity. While this vaccine strategy has produced the majority of successful vaccines in use today, there are also important safety concerns to consider with this approach. In the past, the development of LAVs has been empirical. Blind passage of viruses in various cell types results in the accumulation of multiple attenuating mutations leaving the molecular mechanisms of attenuation unknown. Also, due to the high error rate of RNA viruses and selective pressures of the host environment, these LAVs, derived from such viruses, can potentially revert back to wild-type virulence. This not only puts the vaccinee at risk, but if shed can put those that are unvaccinated at risk as well. While these vaccines have been successful there still remains a need for a rational design strategy by which to create additional LAVs. One approach for rational vaccine design involves increasing the fidelity of the viral RdRp. Increased fidelity decreases the viral mutational frequency thereby reducing the genetic variation the virus needs in order to evade the host imposed bottlenecks to infection. While polymerase mutants exist which decrease viral mutation frequency the mutations are not in conserved regions of the polymerase, which doesn’t lend itself toward using a common mutant approach toward developing a universal vaccine strategy for all RNA viruses. We have identified a conserved lysine residue in the active site of the PV RdRp that acts as a general acid during nucleotide incorporation. Mutation

  1. A two-component rain model for the prediction of attenuation statistics

    Science.gov (United States)

    Crane, R. K.

    1982-01-01

    A two-component rain model has been developed for calculating attenuation statistics. In contrast to most other attenuation prediction models, the two-component model calculates the occurrence probability for volume cells or debris attenuation events. The model performed significantly better than the International Radio Consultative Committee model when used for predictions on earth-satellite paths. It is expected that the model will have applications in modeling the joint statistics required for space diversity system design, the statistics of interference due to rain scatter at attenuating frequencies, and the duration statistics for attenuation events.

  2. Moved by a Rapid Transit

    Science.gov (United States)

    Bueter, C.

    2013-04-01

    Enticing by virtue of its predictability, historical utility, and spectacle, the transit of Venus is a niche event among astronomical phenomena. Though the value of a transit for scientific purposes is now diminished, the brief appearance of Venus silhouetted against the background of the Sun in 2004 moved the artistic community to celebrate the rare alignment. Artists of all ages combined old traditions with fresh technology to create a 21st-century tapestry of music, sculpture, paintings, glasswork, quilts, sky shows, and digital imagery. A full catalog of transit-related art generated over the centuries would feature the sampling of entries presented here and at the Moved by a Rapid Transit website.

  3. Rapid world modelling for robotics

    International Nuclear Information System (INIS)

    The ability to use an interactive world model, whether it is for robotics simulation or most other virtual graphical environments, relies on the users ability to create an accurate world model. Typically this is a tedious process, requiring many hours to create 3-D CAD models of the surfaces within a workspace. The goal of this ongoing project is to develop usable methods to rapidly build world models of real world workspaces. This brings structure to an unstructured environment and allows graphical based robotics control to be accomplished in a reasonable time frame when traditional CAD modelling is not enough. To accomplish this, 3D range sensors are deployed to capture surface data within the workspace. This data is then transformed into surface maps, or models. A 3D world model of the workspace is built quickly and accurately, without ever having to put people in the environment

  4. Rapid Adaptation in Digital Transformation

    DEFF Research Database (Denmark)

    Hansen, Anne Mette; Kræmmergaard, Pernille; Mathiassen, Lars

    2011-01-01

    In today’s highly dynamic environments, organizational leaders need to quickly adapt existing approaches to digital transformation. However, without a shared mindset between IS and business leaders, it is difficult to adopt new approaches in response to changes in the competitive and technology...... landscape. In this article, we share insights gained from two public sector organizations in which IS and business leaders used the Participatory Process Model (PPM) designed by the authors to share their assumptions about IS leadership, challenge existing IT strategies and collaboration patterns and adapt...... the organization’s digitization approach. We demonstrate in detail how the leaders within these two organizations were engaged and offer recommendations for how other organizations can use the PPM to rapidly adapt their approaches to digital transformation through more effective IS leadership roles....

  5. Rapid adaptation to climate change.

    Science.gov (United States)

    Hancock, Angela M

    2016-08-01

    In recent years, amid growing concerns that changing climate is affecting species distributions and ecosystems, predicting responses to rapid environmental change has become a major goal. In this issue, Franks and colleagues take a first step towards this objective (Franks et al. 2016). They examine genomewide signatures of selection in populations of Brassica rapa after a severe multiyear drought. Together with other authors, Franks had previously shown that flowering time was reduced after this particular drought and that the reduction was genetically encoded. Now, the authors have sequenced previously stored samples to compare allele frequencies before and after the drought and identify the loci with the most extreme shifts in frequencies. The loci they identify largely differ between populations, suggesting that different genetic variants may be responsible for reduction in flowering time in the two populations. PMID:27463237

  6. Crustal structure of the Alps as seen by attenuation tomography

    Science.gov (United States)

    Mayor, Jessie; Calvet, Marie; Margerin, Ludovic; Vanderhaeghe, Olivier; Traversa, Paola

    2016-04-01

    We develop a simple tomographic approach exploiting the decay rate of coda waves to map the absorption properties of the crust in a region delimited approximately by the Rhine Graben to the North, the Apennines to the South, the Massif Central to the West and the Dinarides to the East. Our dataset comprises 40 000 coda records of about 2000 weak to moderate crustal earthquakes, with magnitude ranging from 2.8 to 6 and recorded by broad-band, accelerometric and short-period stations. After proper choice of a coda window minimizing the effects of variable epicentral distances, we measure the coda quality factor Qc in five non-overlapping frequency windows covering the 1-32 Hz band for all available source station pairs. These measurements are subsequently converted into maps of absorption quality factor (Qi) using a linearized, approximate relation between Qc and Qi. In practice the following procedure is applied in each frequency band: (1) we divide the target region into 40 × 40 km cells; (2) for each source-station pair, we assign the measured Qc value to each pixel intercepted by the direct ray path; (3) the results are averaged over all paths and subsequently smoothed with a 3 × 3 pixels moving window. Our approach is consistent with the high sensitivity of Qc to the value of Qi between source and station. Our tomographic approach reveals strong lateral variations of absorption with length scales ranging from 100 km to 1000 km. At low frequency (˜ 1 Hz), the correlation with the surface geology is clear, Cenozoic and Mesozoic sedimentary basins (resp. crystalline massifs) being recognized as high (resp. low)-absorption regions. Furthermore the Qi map delineates finer geological features such as the Ivrea Body, the Rhône Valley, or felsic intrusions in the central Alps. At high-frequency (>16 Hz), only the thickest Cenozoic sedimentary deposits show up as high-attenuation regions and a north/south dichotomy is apparent in the absorption structure. The limit

  7. Aspects of flow attenuation performance of retention ponds

    Science.gov (United States)

    Wallis, S. G.; Morgan, C. T.; Heal, K.

    2003-04-01

    The work reported here is part of a wider modelling study into the performance of sustainable urban drainage systems (SUDS) in Scotland. Developments that increase the urbanisation of catchments are now required by the Scottish Environment Protection Agency to include SUDS to protect receiving watercourses from flooding and water quality deterioration. Here we report specifically on some initial simulations of storm water retention ponds. These are normally wet storage facilities that provide both flow attenuation and water quality treatment (from settlement of suspended solids and biological treatment of some pollutants). Here we focus on the flow attenuation characteristics. A sensitivity analysis was performed on a model of a cylindrical pond with outflow through a V-notch weir. The aim of the simulations was to help us to learn about the flow attenuation characteristics of retention ponds, so that later work could be properly focused on the key issues. In addition the flow simulation model underpins later models of water quality and sedimentation, so it was important to ensure that its simulations were realistic. The inflows were constructed using an isosceles triangular inflow hydrograph with a peak flow of 50 l/s, a storm duration of 3.2 hours and a total inflow volume of 288 l. Values of four pond parameters were varied to test model sensitivity: radius, weir angle, weir crest elevation and initial water level. Sensitivity was investigated by observing the changes in several flow attenuation performance indicators. These were total outflow volume, peak outflow and the following three time delays: peak time delay (lag between peaks of outflow and inflow hydrographs), centroid time delay (lag between centroids of outflow and inflow hydrographs) and initial time delay (lag between the initial rise of the outflow and inflow hydrographs). Simulations were carried out using a simple Euler discretisation of the storage routing equation. A time step of 1.5 minutes

  8. Silicone:Worries behind Rapid Growth

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Rapid consumption growth Silicone's extensive application scope, sustained production growth and constant technology improvements have benefited from the rapid development of China's economy overall, and particularly the boom in the manufacturing sector.

  9. Scatter and attenuation correction changes interpretation of gated myocardial perfusion imaging

    DEFF Research Database (Denmark)

    Johansen, Allan; Grupe, Peter; Veje, Annegrete;

    2004-01-01

    Attenuation correction may improve the diagnostic accuracy of myocardial perfusion imaging (MPI). However, few studies have dealt with the clinical consequences for reporting. We compared routine reports based on scatter-corrected MPI (MPI-routine) with consensus readings of scatter-corrected (MPI......-scatter) and scatter plus attenuation-corrected studies (MPI-attenuation) to investigate the impact of attenuation correction on reporting. One hundred consecutive stable angina patients (including 55 men) were investigated in a 99mTc-sestamibi 2-day gated protocol with scatter and attenuation correction. With...... MPI-routine, 53 patients had normal perfusion and 47 abnormal perfusion, compared to 62 and 38 with MPI-attenuation, and 54 and 46, respectively, with MPI-scatter. Agreement between MPI-routine and MPI-attenuation with respect to overall diagnosis (normal/abnormal perfusion) was 89% (kappa=0...

  10. A study on photon attenuation coefficients of different wood materials with different densities

    Science.gov (United States)

    Saritha, B.; Nageswara Rao, A. S.

    2015-12-01

    A study on the variation of linear attenuation coefficients with the densities of the wood samples is under taken. The soft wood and hard wood samples were collected from the forest area of Pakal in Warangal district. The linear and mass attenuation coefficients are measured using gamma ray spectrometry based on NaI (Tl) scintillation detector with energies of 662 KeV and 59.5 KeV respectively. The mass attenuation coefficient values measured from experiment and are compared with theoretical methods using XCOM program. The plots of density versus linear attenuation coefficient for different wood materials correspond to higher order polynomial are presented. It is observed that variation of linear attenuation coefficient depends on densities of materials. The Chloroxylon swietenia with more density has more linear attenuation coefficient at 59.5 KeV and 662 KeV. The variation in attenuation coefficient attributed to chemical composition of wood used in the experiment.

  11. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design.

    Science.gov (United States)

    Yamshchikov, Vladimir; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-01

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E138K and K279M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use.

  12. Improved UTE-based attenuation correction for cranial PET-MR using dynamic magnetic field monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Aitken, A. P.; Giese, D.; Tsoumpas, C.; Schleyer, P.; Kozerke, S.; Prieto, C.; Schaeffter, T., E-mail: Tobias.Schaeffter@kcl.ac.uk [Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, King' s Health Partners, St. Thomas Hospital, London SE1 7EH (United Kingdom)

    2014-01-15

    Purpose: Ultrashort echo time (UTE) MRI has been proposed as a way to produce segmented attenuation maps for PET, as it provides contrast between bone, air, and soft tissue. However, UTE sequences require samples to be acquired during rapidly changing gradient fields, which makes the resulting images prone to eddy current artifacts. In this work it is demonstrated that this can lead to misclassification of tissues in segmented attenuation maps (AC maps) and that these effects can be corrected for by measuring the true k-space trajectories using a magnetic field camera. Methods: The k-space trajectories during a dual echo UTE sequence were measured using a dynamic magnetic field camera. UTE images were reconstructed using nominal trajectories and again using the measured trajectories. A numerical phantom was used to demonstrate the effect of reconstructing with incorrect trajectories. Images of an ovine leg phantom were reconstructed and segmented and the resulting attenuation maps were compared to a segmented map derived from a CT scan of the same phantom, using the Dice similarity measure. The feasibility of the proposed method was demonstrated inin vivo cranial imaging in five healthy volunteers. Simulated PET data were generated for one volunteer to show the impact of misclassifications on the PET reconstruction. Results: Images of the numerical phantom exhibited blurring and edge artifacts on the bone–tissue and air–tissue interfaces when nominal k-space trajectories were used, leading to misclassification of soft tissue as bone and misclassification of bone as air. Images of the tissue phantom and thein vivo cranial images exhibited the same artifacts. The artifacts were greatly reduced when the measured trajectories were used. For the tissue phantom, the Dice coefficient for bone in MR relative to CT was 0.616 using the nominal trajectories and 0.814 using the measured trajectories. The Dice coefficients for soft tissue were 0.933 and 0.934 for the

  13. Yueju Pill Rapidly Induces Antidepressant-Like Effects and Acutely Enhances BDNF Expression in Mouse Brain

    Directory of Open Access Journals (Sweden)

    Wenda Xue

    2013-01-01

    Full Text Available The traditional antidepressants have a major disadvantage in delayed onset of efficacy, and the emerging fast-acting antidepressant ketamine has adverse behavioral and neurotoxic effects. Yueju pill, an herb medicine formulated eight hundred years ago by Doctor Zhu Danxi, has been popularly prescribed in China for alleviation of depression-like symptoms. Although several clinical outcome studies reported the relative short onset of antidepressant effects of Yueju, this has not been scientifically investigated. We, therefore, examined the rapid antidepressant effect of Yueju in mice and tested the underlying molecular mechanisms. We found that acute administration of ethanol extract of Yueju rapidly attenuated depressive-like symptoms in learned helpless paradigm, and the antidepressant-like effects were sustained for at least 24 hours in tail suspension test in ICR mice. Additionally, Yueju, like ketamine, rapidly increased the expression of brain-derived neurotrophic factor (BDNF in the hippocampus, whereas the BDNF mRNA expression remained unaltered. Yueju rapidly reduced the phosphorylation of eukaryotic elongation factor 2 (eEF2, leading to desuppression of BDNF synthesis. Unlike ketamine, both the BDNF expression and eEF2 phosphorylation were revered at 24 hours after Yueju administration. This study is the first to demonstrate the rapid antidepressant effects of an herb medicine, offering an opportunity to improve therapy of depression.

  14. Live Cell Analysis and Mathematical Modeling Identify Determinants of Attenuation of Dengue Virus 2'-O-Methylation Mutant.

    Directory of Open Access Journals (Sweden)

    Bianca Schmid

    2015-12-01

    Full Text Available Dengue virus (DENV is the most common mosquito-transmitted virus infecting ~390 million people worldwide. In spite of this high medical relevance, neither a vaccine nor antiviral therapy is currently available. DENV elicits a strong interferon (IFN response in infected cells, but at the same time actively counteracts IFN production and signaling. Although the kinetics of activation of this innate antiviral defense and the timing of viral counteraction critically determine the magnitude of infection and thus disease, quantitative and kinetic analyses are lacking and it remains poorly understood how DENV spreads in IFN-competent cell systems. To dissect the dynamics of replication versus antiviral defense at the single cell level, we generated a fully viable reporter DENV and host cells with authentic reporters for IFN-stimulated antiviral genes. We find that IFN controls DENV infection in a kinetically determined manner that at the single cell level is highly heterogeneous and stochastic. Even at high-dose, IFN does not fully protect all cells in the culture and, therefore, viral spread occurs even in the face of antiviral protection of naïve cells by IFN. By contrast, a vaccine candidate DENV mutant, which lacks 2'-O-methylation of viral RNA is profoundly attenuated in IFN-competent cells. Through mathematical modeling of time-resolved data and validation experiments we show that the primary determinant for attenuation is the accelerated kinetics of IFN production. This rapid induction triggered by mutant DENV precedes establishment of IFN-resistance in infected cells, thus causing a massive reduction of virus production rate. In contrast, accelerated protection of naïve cells by paracrine IFN action has negligible impact. In conclusion, these results show that attenuation of the 2'-O-methylation DENV mutant is primarily determined by kinetics of autocrine IFN action on infected cells.

  15. Detailed analysis of the promoter activity of an attenuated lentivirus.

    Science.gov (United States)

    Blatti-Cardinaux, Laure; Sanjosé, Leticia; Zahno, Marie-Luise; Zanoni, Reto; Reina, Ramses; Bertoni, Giuseppe

    2016-07-01

    In spite of an eradication campaign that eliminated clinical cases of caprine arthritis encephalitis virus-induced arthritis in the Swiss goat population, seroconversions are still observed. In the affected flocks, viruses belonging mainly to the small ruminant lentivirus A4 subtype are regularly isolated. These viruses are considered attenuated, except in the mammary gland, where high viral loads and histopathological lesions have been observed. We previously characterized and sequenced such field isolates, detecting several potentially attenuating mutations in their LTR. Here we present a detailed analysis of the promoter activity of these genetic elements, which was comparable to those of virulent isolates. An AP-1 binding site was shown to be crucial for promoter activity in reporter gene assays and also in the context of a replicating molecular clone. Other sites, such as AML(vis) and a conserved E-box, appeared to be less crucial. Analysis of a unique AP-4 site showed a clear discrepancy between results obtained with reporter gene assays and those with mutated viruses. Within the limits of this in vitro study, we did not find evidence pointing to the LTR as the genetic correlate of attenuation for these viruses. Finally, the limited replication of SRLV A4 in mammary cell culture could not explain the suggested mammary tropism. In contrast, and in view of the abundance of macrophages in the mammary gland, it is the striking replication capacity of SRLV A4 in these cells, unaffected by all LTR mutations tested, which may explain the apparent mammary tropism of these viruses. PMID:27114068

  16. Intensive Exercise Training During Bed Rest Attenuates Deconditioning

    Science.gov (United States)

    Greenleaf, John E.

    1997-01-01

    Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  17. Attenuation of shock waves in copper and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, W.B.

    1986-06-01

    By using shock pins, data were gathered on the trajectories of shock waves in stainless steel (SS-304L) and oxygen-free-high-conductivity copper (OFHC-Cu). Shock pressures were generated in these materials by impacting the appropriate target with thin (approx.1.5 mm) flying plates. The flying plates in these experiments were accelerated to high velocities (approx.4 km/s) by high explosives. Six experiments were conducted, three using SS-304L as the target material and three experiments using OFHC-Cu as the target material. Peak shock pressures generated in the steel experiments were approximately 109, 130, and 147 GPa and in the copper experiments, the peak shock pressures were approximately 111, 132, and 143 GPa. In each experiment, an attenuation of the shock wave by a following release wave was clearly observed. An extensive effort using two characteristic codes (described in this work) to theoretically calculate the attenuation of the shock waves was made. The efficacy of several different constitutive equations to successfully model the experiments was studied by comparing the calculated shock trajectories to the experimental data. Based on such comparisons, the conclusion can be drawn that OFHC-Cu enters a melt phase at about 130 GPa on the principal Hugoniot. There was no sign of phase changes in the stainless-steel experiments. In order to match the observed attenuation of the shock waves in the SS-304L experiments, it was necessary to include strength effects in the calculations. It was found that the values for the parameters in the strength equations were dependent on the equation of state used in the modeling of the experiments. 66 refs., 194 figs., 77 tabs.

  18. Cilostazol attenuates ovariectomy-induced bone loss by inhibiting osteoclastogenesis.

    Directory of Open Access Journals (Sweden)

    Ke Ke

    Full Text Available Cilostazol has been reported to alleviate the metabolic syndrome induced by increased intracellular adenosine 3',5'-cyclic monophosphate (cAMP levels, which is also associated with osteoclast (OC differentiation. We hypothesized that bone loss might be attenuated via an action on OC by cilostazol.To test this idea, we investigated the effect of cilostazol on ovariectomy (OVX-induced bone loss in mice and on OC differentiation in vitro, using μCT and tartrate-resistant acid phosphatase staining, respectively. Cilostazol prevented from OVX-induced bone loss and decreased oxidative stress in vivo. It also decreased the number and activity of OC in vitro. The effect of cilostazol on reactive oxygen species (ROS occurred via protein kinase A (PKA and cAMP-regulated guanine nucleotide exchange factor 1, two major effectors of cAMP. Knockdown of NADPH oxidase using siRNA of p47phox attenuated the inhibitory effect of cilostazol on OC formation, suggesting that decreased OC formation by cilostazol was partly due to impaired ROS generation. Cilostazol enhanced phosphorylation of nuclear factor of activated T cells, cytoplasmic 1 (NFAT2 at PKA phosphorylation sites, preventing its nuclear translocation to result in reduced receptor activator of nuclear factor-κB ligand-induced NFAT2 expression and decreased binding of nuclear factor-κB-DNA, finally leading to reduced levels of two transcription factors required for OC differentiation.Our data highlight the therapeutic potential of cilostazol for attenuating bone loss and oxidative stress caused by loss of ovarian function.

  19. Optical coherence tomography for blood glucose monitoring through signal attenuation

    Science.gov (United States)

    De Pretto, Lucas R.; Yoshimura, Tania M.; Ribeiro, Martha S.; de Freitas, Anderson Z.

    2016-03-01

    Development of non-invasive techniques for glucose monitoring is crucial to improve glucose control and treatment adherence in patients with diabetes. Hereafter, Optical Coherence Tomography (OCT) may offer a good alternative for portable glucometers, since it uses light to probe samples. Changes in the object of interest can alter the intensity of light returning from the sample and, through it, one can estimate the sample's attenuation coefficient (μt) of light. In this work, we aimed to explore the behavior of μt of mouse's blood under increasing glucose concentrations. Different samples were prepared in four glucose concentrations using a mixture of heparinized blood, phosphate buffer saline and glucose. Blood glucose concentrations were measured with a blood glucometer, for reference. We have also prepared other samples diluting the blood in isotonic saline solution to check the effect of a higher multiple-scattering component on the ability of the technique to differentiate glucose levels based on μt. The OCT system used was a commercial Spectral Radar OCT with 930 nm central wavelength and spectral bandwidth (FWHM) of 100 nm. The system proved to be sensitive for all blood glucose concentrations tested, with good correlations with the obtained attenuation coefficients. A linear tendency was observed, with an increase in attenuation with higher values of glucose. Statistical difference was observed between all groups (p<0.001). This work opens the possibility towards a non-invasive diagnostic modality using OCT for glycemic control, which eliminates the use of analytes and/or test strips, as in the case with commercially available glucometers.

  20. Rapid typing of Coxiella burnetii.

    Directory of Open Access Journals (Sweden)

    Heidie M Hornstra

    Full Text Available Coxiella burnetii has the potential to cause serious disease and is highly prevalent in the environment. Despite this, epidemiological data are sparse and isolate collections are typically small, rare, and difficult to share among laboratories as this pathogen is governed by select agent rules and fastidious to culture. With the advent of whole genome sequencing, some of this knowledge gap has been overcome by the development of genotyping schemes, however many of these methods are cumbersome and not readily transferable between institutions. As comparisons of the few existing collections can dramatically increase our knowledge of the evolution and phylogeography of the species, we aimed to facilitate such comparisons by extracting SNP signatures from past genotyping efforts and then incorporated these signatures into assays that quickly and easily define genotypes and phylogenetic groups. We found 91 polymorphisms (SNPs and indels among multispacer sequence typing (MST loci and designed 14 SNP-based assays that could be used to type samples based on previously established phylogenetic groups. These assays are rapid, inexpensive, real-time PCR assays whose results are unambiguous. Data from these assays allowed us to assign 43 previously untyped isolates to established genotypes and genomic groups. Furthermore, genotyping results based on assays from the signatures provided here are easily transferred between institutions, readily interpreted phylogenetically and simple to adapt to new genotyping technologies.

  1. Rapid purification of recombinant histones.

    Directory of Open Access Journals (Sweden)

    Henrike Klinker

    Full Text Available The development of methods to assemble nucleosomes from recombinant histones decades ago has transformed chromatin research. Nevertheless, nucleosome reconstitution remains time consuming to this day, not least because the four individual histones must be purified first. Here, we present a streamlined purification protocol of recombinant histones from bacteria. We termed this method "rapid histone purification" (RHP as it circumvents isolation of inclusion bodies and thereby cuts out the most time-consuming step of traditional purification protocols. Instead of inclusion body isolation, whole cell extracts are prepared under strongly denaturing conditions that directly solubilize inclusion bodies. By ion exchange chromatography, the histones are purified from the extracts. The protocol has been successfully applied to all four canonical Drosophila and human histones. RHP histones and histones that were purified from isolated inclusion bodies had similar purities. The different purification strategies also did not impact the quality of octamers reconstituted from these histones. We expect that the RHP protocol can be readily applied to the purification of canonical histones from other species as well as the numerous histone variants.

  2. Natural attenuation of hydrocarbon polluted soils in Mexico

    International Nuclear Information System (INIS)

    Crude oil and hydrocarbon by-proudcts are the most common pollutants in Mexico. In the last years, the two terms, contamination and remediation have being re-defined; also, based on both the scientific advancement and the human risk, the sustentability of remediation technologies and the definition of cleaning levels has been taking place. In this context, the Natural Attenuation of soils is a viable and low cost remediation choice, defined as the degradation of organic compounds without artificial stimulation, through microbial activity including physical processes, such as volatilization, dilution, sorption, and hydraulic dispersion. (Author)

  3. Research progress in live attenuated Brucella vaccine development.

    Science.gov (United States)

    Wang, Zhen; Wu, Qingmin

    2013-01-01

    Brucella spp. are facultative intracellular bacteria that cause brucellosis, which is a globally occurring zoonotic disease that is characterized by abortion in domestic animals and undulant fever, arthritis, endocarditis, and meningitis in humans. There are currently no licensed vaccines against brucellosis for human use, and only a few licensed live Brucella vaccines are available for use in animals. However, the available animal vaccines may cause abortion and are associated with lower protection rates in animals and higher virulence in humans. Much research has been performed recently to develop novel Brucella vaccines for the prevention and control of animal brucellosis. This article discusses the approaches and strategies for novel live attenuated vaccine development.

  4. Live attenuated varicella vaccine in children with leukemia in remission.

    Science.gov (United States)

    Gershon, A A; Steinberg, S; Galasso, G; Borkowsky, W; Larussa, P; Ferrara, A; Gelb, L

    1984-09-01

    One-hundred-ninety-one children with acute leukemia in remission for at least one year were immunized with 1 or more doses of live attenuated varicella vaccine. All were susceptible to varicella prior to vaccination. The only significant side effect was mild to moderate rash, seen especially in children with maintenance chemotherapy temporarily suspended for one week before and one week after vaccination. Children with rash were at some risk (10%) to transmit vaccine virus to varicella susceptibles with whom they had close contact.

  5. Pharmacologically induced hypothermia attenuates traumatic brain injury in neonatal rats.

    Science.gov (United States)

    Gu, Xiaohuan; Wei, Zheng Zachory; Espinera, Alyssa; Lee, Jin Hwan; Ji, Xiaoya; Wei, Ling; Dix, Thomas A; Yu, Shan Ping

    2015-05-01

    Neonatal brain trauma is linked to higher risks of mortality and neurological disability. The use of mild to moderate hypothermia has shown promising potential against brain injuries induced by stroke and traumatic brain injury (TBI) in various experimental models and in clinical trials. Conventional methods of physical cooling, however, are difficult to use in acute treatments and in induction of regulated hypothermia. In addition, general anesthesia is usually required to mitigate the negative effects of shivering during physical cooling. Our recent investigations demonstrate the potential therapeutic benefits of pharmacologically induced hypothermia (PIH) using the neurotensin receptor (NTR) agonist HPI201 (formerly known as ABS201) in stroke and TBI models of adult rodents. The present investigation explored the brain protective effects of HPI201 in a P14 rat pediatric model of TBI induced by controlled cortical impact. When administered via intraperitoneal (i.p.) injection, HPI201 induced dose-dependent reduction of body and brain temperature. A 6-h hypothermic treatment, providing an overall 2-3°C reduction of brain and body temperature, showed significant effect of attenuating the contusion volume versus TBI controls. Attenuation occurs whether hypothermia is initiated 15min or 2h after TBI. No shivering response was seen in HPI201-treated animals. HPI201 treatment also reduced TUNEL-positive and TUNEL/NeuN-colabeled cells in the contusion area and peri-injury regions. TBI-induced blood-brain barrier damage was attenuated by HPI201 treatment, evaluated using the Evans Blue assay. HPI201 significantly decreased MMP-9 levels and caspase-3 activation, both of which are pro-apototic, while it increased anti-apoptotic Bcl-2 gene expression in the peri-contusion region. In addition, HPI201 prevented the up-regulation of pro-inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6. In sensorimotor activity assessments, rats in the HPI201

  6. Disturbance Attenuation State-Feedback Control for Uncertain Interconnected Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems viastate feedback. This class of systems are described by a state space model, which contains unknown nonlinear interactionand time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach wedesign state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the inter-connected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate theresults.

  7. Multi-resolution inversion algorithm for the attenuated radon transform

    KAUST Repository

    Barbano, Paolo Emilio

    2011-09-01

    We present a FAST implementation of the Inverse Attenuated Radon Transform which incorporates accurate collimator response, as well as artifact rejection due to statistical noise and data corruption. This new reconstruction procedure is performed by combining a memory-efficient implementation of the analytical inversion formula (AIF [1], [2]) with a wavelet-based version of a recently discovered regularization technique [3]. The paper introduces all the main aspects of the new AIF, as well numerical experiments on real and simulated data. Those display a substantial improvement in reconstruction quality when compared to linear or iterative algorithms. © 2011 IEEE.

  8. Attenuating wind turbine loads through model based individual pitch control

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    In this paper we consider wind turbine load attenuation through model based control. Asymmetric loads caused by the wind field can be reduced by pitching the blades individually. To this end we investigate the use of stochastic models of the wind which can be included in a model based individual...... pitch controller design. In this way the variability of the wind can be estimated and compensated for by the controller. The wind turbine model is in general time-variant due to its rotational nature. For this reason the modeling and control is carried out in so-called multiblade coordinates...

  9. Attenuation, dispersion and nonlinearity effects in graphene-based waveguides.

    Science.gov (United States)

    Lima, Almir Wirth; Mota, João Cesar Moura; Sombra, Antonio Sergio Bezerra

    2015-01-01

    We simulated and analyzed in detail the behavior of ultrashort optical pulses, which are typically used in telecommunications, propagating through graphene-based nanoribbon waveguides. In this work, we showed the changes that occur in the Gaussian and hyperbolic secant input pulses due to the attenuation, high-order dispersive effects and nonlinear effects. We concluded that it is possible to control the shape of the output pulses with the value of the input signal power and the chemical potential of the graphene nanoribbon. We believe that the obtained results will be highly relevant since they can be applied to other nanophotonic devices, for example, filters, modulators, antennas, switches and other devices.

  10. Regional Lg attenuation for the continental United States

    Science.gov (United States)

    Benz, H.M.; Frankel, A.; Boore, D.M.

    1997-01-01

    Measurements of the Fourier amplitude spectra of Lg phases recorded at high frequency (0.5 to 14.0 Hz) by broadband seismic stations are used to determine regional attenuation relationships for southern California, the Basin and Range Province, the central United States, and the northeastern United States and southeastern Canada. Fourier spectral amplitudes were measured every quarter octave from Lg phases windowed between 3.0 and 3.7 km sec-1 and recorded in the distance range of 150 to 1000 km. Attenuation at each frequency is determined by assuming a geometrical spreading exponent of 0.5 and inverting for Q and source and receiver terms. Both southern California and the Basin and Range Province are well described by low Lg Q and frequency-dependent attenuation. Lg spectral amplitudes in southern California are fit at low frequencies (0.625 to 0.875 Hz) by a constant Lg Q of 224 and by a frequency-dependent Lg Q function Q = 187-7+7 f0.55(??0.03) in the frequency band 1.0 to 7.0 Hz. The Basin and Range Province is characterized by a constant Lg Q of 192 for frequencies of 0.5 to 0.875 Hz and by the frequency-dependent Lg Q function Q = 235-11+11 f0.56(??0.04) in the frequency band 1.0 to 5.0 Hz. A change in frequency dependence above 5.0 Hz is possible due to contamination of the Lg window by Pn and Sn phases. Lg spectral amplitudes in the central United States are fit by a mean frequency-independent Lg Q of 1291 for frequencies of 1.5 to 7.0 Hz, while a frequency-dependent Lg Q of Q = 1052-83+91(f/1.5)0.22(??0.06) fits the Lg spectral amplitudes for the northeastern United States and southeastern Canada over the passband 1.5 to 14.0 Hz. Attenuation measurements for these areas were restricted to frequencies >1.5 Hz due to larger microseismic noise levels at the lower frequencies.

  11. Uncommon breast tumor attenuation artifact on radionuclide ventriculography.

    Science.gov (United States)

    Metrard, Gilles; Girault, Sylvie; Capitain, Olivier; Jeanguillaume, Christian; Rakotonirina, Hervé; Berthelot, Cécile; Le Jeune, Jean-Jacques; Morel, Olivier

    2008-04-01

    A 39-year-old woman with locally advanced left breast cancer (T4 N0 M0) underwent equilibrium radionuclide ventriculography for baseline assessment of left ventricular function before neoadjuvant chemotherapy. The left ventricular ejection fraction was 76% at 75 beats per minute, without localized wall motion abnormality. In the best septal left anterior oblique projection, a large photopenic "halo" surrounded the cardiac chambers, mimicking a pericardial effusion. In fact, this aspect resulted from an attenuation artifact by a large left breast tumor, as demonstrated by FDG-PET/CT imaging. PMID:18356673

  12. Gamma-ray attenuation coefficients in bismuth borate glasses

    International Nuclear Information System (INIS)

    Mass attenuation coefficients of glasses in the system: xBi2O3(1-x)B2O3 (x=0.30, 0.35, 0.40, 0.45 and 0.55) were determined at 356, 662, 1173 and 1332 keV photon energies using a narrow beam transmission method. Appreciable variations were observed in these coefficients due to changes in the chemical composition of glasses. These coefficients were then used to determine effective atomic numbers of glass samples, which were found to be constant with bismuth concentration and energy

  13. Natural attenuation of hydrocarbon polluted soils in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Linares, L.; Rojas-Avelizapa, N.; Roldan-Carrillo, T.; Islas-Ramirez, M.

    2009-07-01

    Crude oil and hydrocarbon by-proudcts are the most common pollutants in Mexico. In the last years, the two terms, contamination and remediation have being re-defined; also, based on both the scientific advancement and the human risk, the sustentability of remediation technologies and the definition of cleaning levels has been taking place. In this context, the Natural Attenuation of soils is a viable and low cost remediation choice, defined as the degradation of organic compounds without artificial stimulation, through microbial activity including physical processes, such as volatilization, dilution, sorption, and hydraulic dispersion. (Author)

  14. Bicarbonate attenuates arterial desaturation during maximal exercise in humans

    DEFF Research Database (Denmark)

    Nielsen, Henning B; Bredmose, Per P; Strømstad, Morten;

    2002-01-01

    was not significantly changed from resting values in the last minute of Sal exercise, but in the Bic trial it increased from 40.5 +/- 0.5 to 45.9 +/- 2.0 Torr (P ventilation was lowered during exercise with Bic (155 +/- 14 vs. 142 +/- 13 l/min; P ... in the difference between the end-tidal O2 pressure and arterial PO2 was similar in the two trials. Also, pulmonary O2 uptake and changes in muscle oxygenation as determined by near-infrared spectrophotometry during exercise were similar. The enlarged blood-buffering capacity after infusion of Bic attenuated...

  15. Predicting spectral and PAR light attenuation in Greenlandic coastal waters

    DEFF Research Database (Denmark)

    Murray, Ciarán; Markager, Stiig; Stedmon, Colin

    present models for spectral and PAR (photosynthetically active radiation) attenuation in two contrasting Greenlandic fjords, Godthåbsfjord (SW Greenland) and Young Sound (NE Greenland). The fjords differ in the character and concentrations of optically active components present: dissolved organic material...... (CDOM), phytoplankton pigments and inorganic particles. These differences are due in part to hydrography and to the sources of meltwater: respectively, fjord-terminating and land-terminating glaciers. We present a model to explain the variation in spectral and PAR irradiance in terms of the variation...

  16. Predicting Spectral and PAR Light Attenuation in Greenlandic Coastal Waters

    DEFF Research Database (Denmark)

    Murray, Ciarán; Stedmon, Colin A.; Markager, Stiig

    present models for spectral and PAR (photosynthetically active radiation) attenuation in two contrasting Greenlandic fjords, Godthåbsfjord (SW Greenland) and Young Sound (NE Greenland). The fjords differ in the character and concentrations of optically active components present: dissolved organic material...... (CDOM), phytoplankton pigments and inorganic particles. These differences are due in part to hydrography and to the sources of meltwater: respectively, fjord-terminating and land-terminating glaciers. We present a model to explain the variation in spectral and PAR irradiance in terms of the variation...

  17. Finite-time disturbance attenuation of nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    MO LiPo; JIA YingMin; ZHENG ZhiMing

    2009-01-01

    This paper is devoted to the finite-time disturbance attenuation problem of affine nonlinear systems.Based on the finite time Lyapunov stability theory,some finite-time H_∞ performance criterions are derived.Then the state-feedback control law is designed and the structure of such a controller is investigated.Furthermore,it is shown that the H_∞ controller can also make the closed-loop system satisfy finite-time H_∞ performance for nonlinear homogeneous systems.An example is provided to demonstrate the effectiveness of the presented results.

  18. Relationship between normalized light intensity and attenuated total reflection ratio

    Institute of Scientific and Technical Information of China (English)

    Yingcai Wu; Zhengtian Gu

    2008-01-01

    Attenuated total reflection (ATR) ratio is usually utilized to study the properties of surface plasmon resonance (SPR) sensors. The relationship between normalized light intensity and ATR ratio is investigated, and a modification coefficient is put forward to describe the relationship. A mathematical expression is built up for the coefficient based on Fresnel principle. The result shows that the ATR ratio, which cannot be measured directly in experiments, can be determined with the coefficient and the normalized intensity of light. The characteristic of the coefficient is also discussed.

  19. Attenuation and source properties at the Coso Geothermal area, California

    Science.gov (United States)

    Hough, S.E.; Lees, J.M.; Monastero, F.

    1999-01-01

    We use a multiple-empirical Green's function method to determine source properties of small (M -0.4 to 1.3) earthquakes and P- and S-wave attenuation at the Coso Geothermal Field, California. Source properties of a previously identified set of clustered events from the Coso geothermal region are first analyzed using an empirical Green's function (EGF) method. Stress-drop values of at least 0.5-1 MPa are inferred for all of the events; in many cases, the corner frequency is outside the usable bandwidth, and the stress drop can only be constrained as being higher than 3 MPa. P- and S-wave stress-drop estimates are identical to the resolution limits of the data. These results are indistinguishable from numerous EGF studies of M 2-5 earthquakes, suggesting a similarity in rupture processes that extends to events that are both tiny and induced, providing further support for Byerlee's Law. Whole-path Q estimates for P and S waves are determined using the multiple-empirical Green's function (MEGF) method of Hough (1997), whereby spectra from clusters of colocated events at a given station are inverted for a single attenuation parameter, ??, with source parameters constrained from EGF analysis. The ?? estimates, which we infer to be resolved to within 0.01 sec or better, exhibit almost as much scatter as a function of hypocentral distance as do values from previous single-spectrum studies for which much higher uncertainties in individual ?? estimates are expected. The variability in ?? estimates determined here therefore suggests real lateral variability in Q structure. Although the ray-path coverage is too sparse to yield a complete three-dimensional attenuation tomographic image, we invert the inferred ?? value for three-dimensional structure using a damped least-squares method, and the results do reveal significant lateral variability in Q structure. The inferred attenuation variability corresponds to the heat-flow variations within the geothermal region. A central low

  20. Plasticity within non-cerebellar pathways rapidly shapes motor performance in vivo.

    Science.gov (United States)

    Mitchell, Diana E; Della Santina, Charles C; Cullen, Kathleen E

    2016-01-01

    Although cerebellar mechanisms are vital to maintain accuracy during complex movements and to calibrate simple reflexes, recent in vitro studies have called into question the widely held view that synaptic changes within cerebellar pathways exclusively guide alterations in motor performance. Here we investigate the vestibulo-ocular reflex (VOR) circuitry by applying temporally precise activation of vestibular afferents in awake-behaving monkeys to link plasticity at different neural sites with changes in motor performance. Behaviourally relevant activation patterns produce rapid attenuation of direct pathway VOR neurons, but not their nerve input. Changes in the strength of this pathway are sufficient to induce a lasting decrease in the evoked VOR. In addition, indirect brainstem pathways display complementary nearly instantaneous changes, contributing to compensating for the reduced sensitivity of primary VOR neurons. Taken together, our data provide evidence that multiple sites of plasticity within VOR pathways can rapidly shape motor performance in vivo. PMID:27157829

  1. Plasticity within non-cerebellar pathways rapidly shapes motor performance in vivo

    Science.gov (United States)

    Mitchell, Diana E.; Della Santina, Charles C.; Cullen, Kathleen E.

    2016-01-01

    Although cerebellar mechanisms are vital to maintain accuracy during complex movements and to calibrate simple reflexes, recent in vitro studies have called into question the widely held view that synaptic changes within cerebellar pathways exclusively guide alterations in motor performance. Here we investigate the vestibulo-ocular reflex (VOR) circuitry by applying temporally precise activation of vestibular afferents in awake-behaving monkeys to link plasticity at different neural sites with changes in motor performance. Behaviourally relevant activation patterns produce rapid attenuation of direct pathway VOR neurons, but not their nerve input. Changes in the strength of this pathway are sufficient to induce a lasting decrease in the evoked VOR. In addition, indirect brainstem pathways display complementary nearly instantaneous changes, contributing to compensating for the reduced sensitivity of primary VOR neurons. Taken together, our data provide evidence that multiple sites of plasticity within VOR pathways can rapidly shape motor performance in vivo. PMID:27157829

  2. The new approach of polarimetric attenuation correction for improving radar quantitative precipitation estimation(QPE)

    Science.gov (United States)

    Gu, Ji-Young; Suk, Mi-Kyung; Nam, Kyung-Yeub; Ko, Jeong-Seok; Ryzhkov, Alexander

    2016-04-01

    To obtain high-quality radar quantitative precipitation estimation data, reliable radar calibration and efficient attenuation correction are very important. Because microwave radiation at shorter wavelength experiences strong attenuation in precipitation, accounting for this attenuation is the essential work at shorter wavelength radar. In this study, the performance of different attenuation/differential attenuation correction schemes at C band is tested for two strong rain events which occurred in central Oklahoma. And also, a new attenuation correction scheme (combination of self-consistency and hot-spot concept methodology) that separates relative contributions of strong convective cells and the rest of the storm to the path-integrated total and differential attenuation is among the algorithms explored. A quantitative use of weather radar measurement such as rainfall estimation relies on the reliable attenuation correction. We examined the impact of attenuation correction on estimates of rainfall in heavy rain events by using cross-checking with S-band radar measurements which are much less affected by attenuation and compared the storm rain totals obtained from the corrected Z and KDP and rain gages in these cases. This new approach can be utilized at shorter wavelength radars efficiently. Therefore, it is very useful to Weather Radar Center of Korea Meteorological Administration preparing X-band research dual Pol radar network.

  3. Positron-based attenuation correction for Positron Emission Tomography data using MCNP6 code

    Directory of Open Access Journals (Sweden)

    M. Saeed

    2016-01-01

    Full Text Available This paper presents the Monte Carlo simulation of the attenuation correction for Positron Emission Tomography (PET data using MCNP6 code. Two attenuation correction maps have been generated, one for correcting the attenuation effect in a homogeneous phantom, which is a cylindrical volume of water and the other for correcting the attenuation effect in a heterogeneous phantom, which is a cylindrical volume of water within which, there are two small cylinders of bone-equivalent materials. These maps are derived from the data acquired as a result of transmission scans using a positron-emitting rod source. The attenuation map generated using this method does not need to be scaled because it is directly built for an energy of 511 keV. For each phantom, three types of simulations are done, one to estimate the radiotracer distribution in the phantom (emission scan and two to estimate the distribution of attenuation coefficients in this phantom (transmission scans, the first with a blank field of view (FOV and the second when the phantom exists in the FOV. From the transmission scans data, the attenuation map for each phantom is derived and after that it has been applied to the corresponding emission scan data during PET image reconstruction process to obtain the attenuation-corrected image. The images of the radiotracer distribution in each phantom reached in this study illustrate the quantitative and qualitative improvements in the image quality after attenuation correction than that before the attenuation correction.

  4. SU-F-BRE-10: Methods to Simulate and Measure the Attenuation for Modeling a Couch Top with Rails for FFF Treatment Delivery On the Varian Edge Linac

    Energy Technology Data Exchange (ETDEWEB)

    Gulam, M; Gardner, S; Zhao, B; Snyder, K; Song, K; Li, H; Gordon, J; Wen, N; Chetty, I [Henry Ford Health System, Detroit, MI (United States); Kearns, W [Varian Medical Systems, Clemmons, NC (United States)

    2014-06-15

    Purpose: To measure attenuation for modelling of the KVue Couchtop for 6X and 10X FFF SRS/SBRT treatment Methods: Treatment planning simulation studies were done using 6X FFF beams to estimate the dosimetric impact of KVue couchtops (including the Q-Fix IGRT [carbon fiber] and Calypso [nonconductive Kevlar material]) with a structure model obtained from a research workstation (Eclipse, advanced planning interface (API) v13). Prior to installation on the Varian Edge linac, the couchtop along with (Kevlar) rails were CT scanned with the rails at various positions. An additional scan with the couchtop 15cm above the CT table top was obtained with 20cm solid water to facilitate precised/indexed data acquisition. Measurements for attenuation were obtained for field sizes of 2, 4 and 10 cm{sup 2} at 42 gantry angles including 6 pairs of opposing fields and other angles for oblique delivery where the beams traversed the couchtop and or rails. The delivery was fully automated with xml scripts running in developer mode. The results were then used to determine an accurate structure model for AAA (Eclipse v11) planning of IMRT and RapidArc delivery. Results: The planning simulation relative dose attenuation for oblique entry was not significantly different than the Exact IGRT or BrainLab iBeam couch except that the rails added 6% additional attenuation. The relative attenuation measurements for PA, PA (rails: inner position), oblique, oblique (rails: outer position), oblique (rails: inner position) were: −2.0%, −2.5%, −15.6%, −2.5%, −5.0% for 6X FFF and −1.4%, −1.5%, −12.2%, − 2.5%, −5.0% for 10X FFF with slight decrease in attenuation versus field size. A Couch structure model (with HU values) was developed. Calculation compared to measurement showed good agreement except for oblique (rails: outer position) where differences approached a magnitude of 6%. Conclusion: A model of the couch structures has been developed accounting for attenuation for FFF

  5. SU-F-BRE-10: Methods to Simulate and Measure the Attenuation for Modeling a Couch Top with Rails for FFF Treatment Delivery On the Varian Edge Linac

    International Nuclear Information System (INIS)

    Purpose: To measure attenuation for modelling of the KVue Couchtop for 6X and 10X FFF SRS/SBRT treatment Methods: Treatment planning simulation studies were done using 6X FFF beams to estimate the dosimetric impact of KVue couchtops (including the Q-Fix IGRT [carbon fiber] and Calypso [nonconductive Kevlar material]) with a structure model obtained from a research workstation (Eclipse, advanced planning interface (API) v13). Prior to installation on the Varian Edge linac, the couchtop along with (Kevlar) rails were CT scanned with the rails at various positions. An additional scan with the couchtop 15cm above the CT table top was obtained with 20cm solid water to facilitate precised/indexed data acquisition. Measurements for attenuation were obtained for field sizes of 2, 4 and 10 cm2 at 42 gantry angles including 6 pairs of opposing fields and other angles for oblique delivery where the beams traversed the couchtop and or rails. The delivery was fully automated with xml scripts running in developer mode. The results were then used to determine an accurate structure model for AAA (Eclipse v11) planning of IMRT and RapidArc delivery. Results: The planning simulation relative dose attenuation for oblique entry was not significantly different than the Exact IGRT or BrainLab iBeam couch except that the rails added 6% additional attenuation. The relative attenuation measurements for PA, PA (rails: inner position), oblique, oblique (rails: outer position), oblique (rails: inner position) were: −2.0%, −2.5%, −15.6%, −2.5%, −5.0% for 6X FFF and −1.4%, −1.5%, −12.2%, − 2.5%, −5.0% for 10X FFF with slight decrease in attenuation versus field size. A Couch structure model (with HU values) was developed. Calculation compared to measurement showed good agreement except for oblique (rails: outer position) where differences approached a magnitude of 6%. Conclusion: A model of the couch structures has been developed accounting for attenuation for FFF beams

  6. Attenuated total reflectance fourier transform infrared analysis of fly ash geopolymer gel aging.

    Science.gov (United States)

    Rees, Catherine A; Provis, John L; Lukey, Grant C; van Deventer, Jannie S J

    2007-07-17

    Structural changes in fly ash geopolymers activated with different sodium hydroxide and silicate concentrations are investigated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy over a period of 200 days. A strong correlation is found between the concentration of silicate monomer in the activating solution and the position of the main Si-O-T stretching band in the FTIR spectrum, which gives an indication of the relative changes in the gel Si/Al ratio. The FTIR spectra of geopolymer samples with activating solution concentrations of up to 1.2 M SiO2 indicate that an Al-rich gel forms before the final gel composition is reached. The time required for the system to reach a steady gel composition depends on the silicate activating solution concentration and speciation. Geopolymers activated with solutions containing predominantly high-order silicate species rapidly reach a steady gel composition without first forming an Al-rich gel. A minimum silicate monomer concentration of approximately 0.6 M is required to shift the geopolymer synthesis mechanism from hydroxide activation to silicate activation. Silicate speciation in the activating solutions also affects zeolite formation and geopolymer microstructures, with a more homogeneous microstructure and less zeolite formation observed at a higher SiO2 content.

  7. Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function.

    Directory of Open Access Journals (Sweden)

    Ye-Ji Jeong

    Full Text Available Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA, an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

  8. Oral exposure to Phytomonas serpens attenuates thrombocytopenia and leukopenia during acute infection with Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Rosiane V da Silva

    Full Text Available Mice infected with Trypanosoma cruzi, the agent of Chagas disease, rapidly develop anemia and thrombocytopenia. These effects are partially promoted by the parasite trans-sialidase (TS, which is shed in the blood and depletes sialic acid from the platelets, inducing accelerated platelet clearance and causing thrombocytopenia during the acute phase of disease. Here, we demonstrate that oral immunization of C57BL/6 mice with Phytomonas serpens, a phytoflagellate parasite that shares common antigens with T. cruzi but has no TS activity, reduces parasite burden and prevents thrombocytopenia and leukopenia. Immunization also reduces platelet loss after intraperitoneal injection of TS. In addition, passive transfer of immune sera raised in mice against P. serpens prevented platelet clearance. Thus, oral exposure to P. serpens attenuates the progression of thrombocytopenia induced by TS from T. cruzi. These findings are not only important for the understanding of the pathogenesis of T. cruzi infection but also for developing novel approaches of intervention in Chagas disease.

  9. Characterization of Printing Inks Using DART-Q-TOF-MS and Attenuated Total Reflectance (ATR) FTIR.

    Science.gov (United States)

    Williamson, Rhett; Raeva, Anna; Almirall, Jose R

    2016-05-01

    The rise in improved and widely accessible printing technology has resulted in an interest to develop rapid and minimally destructive chemical analytical techniques that can characterize printing inks for forensic document analysis. Chemical characterization of printing inks allows for both discrimination of inks originating from different sources and the association of inks originating from the same source. Direct analysis in real-time mass spectrometry (DART-MS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used in tandem to analyze four different classes of printing inks: inkjets, toners, offset, and intaglio. A total of 319 samples or ~ 80 samples from each class were analyzed directly on a paper substrate using the two methods. DART-MS was found to characterize the semi-volatile polymeric vehicle components, while ATR-FTIR provided chemical information associated with the bulk components of these inks. Complimentary data results in improved discrimination when both techniques are used in succession resulting in >96% discrimination for all toners, 95% for all inkjets, >92% for all offset, and >54% for all intaglio inks. PMID:27122410

  10. Propagation simulation and attenuation law analysis of seismic wave in elastoplastic tunnel rock medium

    Institute of Scientific and Technical Information of China (English)

    ZHAO Tong-bin; LI Jian-gong; XIAO Ya-xun; CHENG Guo-qiang

    2007-01-01

    The energy caused by the dynamic impact in mining engineering forth release and spread by the way of seismic waves, monitoring is an effective way for forecasting mine dynamical disasters, such as rockburst and coal and gas outburst. Three-dimensional dynamic model was built to simulate the propagating progress of seismic waves in the elastoplastic tunnel rock and analyzed the propagating law of perturbation acceleration around tunnel, based on the finite element dynamic analysis software ANSYS/LS-DYNA.The simulation results indicate that: (1) The propagation attenuation of seismic wave is a negative index relationship; (2) The acceleration amplitude of seismic wave decays rapidly in near-field and decays slowly in far-field; (3) When the perturbation is generated in the dead ahead of tunnel, the acceleration of seismic wave become smaller and smaller away from the roadway-rib;(4) The elastic and plastic stress state of tunnel rock is also an important factor for propagation process of wave, the energy of seismic wave is mainly consumed for geometric spreading and plastic deformation in propagation in the elastoplastic medium model.

  11. Gamma and neutron attenuation behaviours of boron carbide–silicon carbide composites

    International Nuclear Information System (INIS)

    Highlights: • Gamma and neutron attenuation behaviours of B4C–SiC composites were investigated. • Increasing SiC ratio increases gamma attenuation behaviour of the B4C–SiC composites. • Increasing SiC ratio decrease attenuation behaviour of the B4C–SiC composites. • HVT values of the B4C–SiC composites were calculated for Cs-137, Co-60 and Pu–Be sources. • Experimental mass attenuation coefficient are compatible with theoretical (XCOM) values. - Abstract: In this study, the gamma and neutron attenuation behaviors of pure boron carbide and boron carbide–silicon carbide composites which include three different silicon carbide ratios (20%, 30%, and 40%) by volume were investigated against Cs-137, Co-60 gamma radioisotope sources and Pu–Be neutron source. Transmission technique was used in the experiments to investigate the gamma and neutron attenuation properties of the materials. Linear and mass attenuation coefficients of the samples were determined for 0.662 (Cs-137) and 1.25 MeV (Co-60) energetic gamma rays. In addition the total macroscopic cross-sections (∑T) were calculated for the materials against Pu–Be neutron source. Theoretical mass attenuation coefficients were calculated from XCOM computer code. The experimental and theoretical mass attenuation coefficients were compared and evaluated with each other. In addition half value thickness (HVT) calculations were carried out by using linear attenuation coefficients and total macroscopic cross-sections. The results showed that increasing silicon carbide ratio decreases HVTs against Cs-137 and Co-60 gamma radioisotope sources whereas increases HVTs against Pu–Be neutron source. The mass attenuation coefficients were compatible with the theoretical (XCOM) values. Increasing silicon carbide ratio in boron carbide–silicon carbide composites causes higher gamma attenuation and lower neutron attenuation values

  12. Immobilized nickel hexacyanoferrate on activated carbons for efficient attenuation of radio toxic Cs(I) from aqueous solutions

    Science.gov (United States)

    Lalhmunsiama; Lalhriatpuia, C.; Tiwari, Diwakar; Lee, Seung-Mok

    2014-12-01

    The aim of this study is to immobilize nickel hexacyanoferrate onto the large surface of activated carbons (ACs) precursor to rice hulls and areca nut waste materials. These nickel hexacyanoferrate immobilized materials are then assessed in the effective attenuation of radio logically important cesium ions from aqueous solutions. The solid samples are characterized by the XRD analytical method and surface morphology is obtained from the SEM images. The batch reactor experiments show that an increase in sorptive pH (2.0-10.0) apparently not affecting the high percent uptake of Cs(I). Equilibrium modeling studies suggest that the data are reasonably and relatively fitted well to the Langmuir adsorption isotherm. Kinetic studies show that sorption process is fairly rapid and the kinetic data are fitted well to the pseudo-second order rate model. Increasing the background electrolyte concentration from 0.001 to 0.1 mol/L NaCl causes insignificant decrease in Cs(I) removal which infers the higher selectivity of these materials for Cs(I) from aqueous solutions. Further, the column reactor operations enable to obtain the breakthrough data which are then fitted to the Thomas non-linear equation as to obtain the loading capacity of column for Cs(I). The results show that the modified materials show potential applicability in the attenuation of radio toxic cesium from aqueous solution.

  13. 78 FR 11678 - Notice of Inventory Completion: Grand Rapids Public Museum, Grand Rapids, MI

    Science.gov (United States)

    2013-02-19

    ... National Park Service Notice of Inventory Completion: Grand Rapids Public Museum, Grand Rapids, MI AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The Grand Rapids Public Museum has completed an... Grand Rapids Public Museum. Repatriation of the human remains and associated funerary objects to...

  14. 77 FR 11575 - Notice of Inventory Completion: Grand Rapids Public Museum, Grand Rapids, MI

    Science.gov (United States)

    2012-02-27

    ... National Park Service Notice of Inventory Completion: Grand Rapids Public Museum, Grand Rapids, MI AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The Grand Rapids Public Museum has completed an... Rapids Public Museum. Repatriation of the human remains and associated funerary objects to the...

  15. Whole-body PET/MRI: The effect of bone attenuation during MR-based attenuation correction in oncology imaging

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, M.C., E-mail: marianne.aznar@regionh.dk [Department of Oncology, Section of Radiotherapy 3994, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen (Denmark); Sersar, R., E-mail: rachidadk@hotmail.com [DTU Informatics, Technical University of Denmark, Kongens Lyngby (Denmark); Saabye, J., E-mail: julie_saa@hotmail.com [DTU Informatics, Technical University of Denmark, Kongens Lyngby (Denmark); Ladefoged, C.N., E-mail: claesnl@gmail.com [Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Andersen, F.L., E-mail: Flemming.Andersen@regionh.dk [Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Rasmussen, J.H., E-mail: jacobrasmu@gmail.com [Department of Oncology, Section of Radiotherapy 3994, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen (Denmark); Löfgren, J., E-mail: Johan.Loefgren@regionh.dk [Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Beyer, T., E-mail: thomas.beyer@meduniwien.ac.at [Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna (Austria)

    2014-07-15

    Purpose: In combined PET/MRI standard PET attenuation correction (AC) is based on tissue segmentation following dedicated MR sequencing and, typically, bone tissue is not represented. We evaluate PET quantification in whole-body (WB)-PET/MRI following MR-AC without considering bone attenuation and then investigate different strategies to account for bone tissue in clinical PET/MR imaging. To this purpose, bone tissue representation was extracted from separate CT images, and different bone representations were simulated from hypothetically derived MR-based bone classifications. Methods: Twenty oncology patients referred for a PET/CT were injected with either [18F]-FDG or [18F]-NaF and imaged on PET/CT (Biograph TruePoint/mCT, Siemens) and PET/MRI (mMR, Siemens) following a standard single-injection, dual-imaging clinical WB-protocol. Routine MR-AC was based on in-/opposed-phase MR imaging (orgMR-AC). PET(/MRI) images were reconstructed (AW-OSEM, 3 iterations, 21 subsets, 4 mm Gaussian) following routine MR-AC and MR-AC based on four modified attenuation maps. These modified attenuation maps were created for each patient by non-linear co-registration of the CT images to the orgMR-AC images, and adding CT bone mask values representing cortical bone: 1200 HU (cortCT), spongiosa bone: 350 HU (spongCT), average CT value (meanCT) and original CT values (orgCT). Relative difference images of the PET following AC using the modified attenuation maps were compared. SUVmean was calculated in anatomical reference regions and for PET-positive lesions. Results: The relative differences in SUVmean across patients following orgMR-AC and orgCT in soft tissue lesions and in bone lesions were similar (range: 0.0% to −22.5%), with an average underestimation of SUVmean of 7.2% and 10.0%, respectively when using orgMR-AC. In bone lesions, spongCT values were closest to orgCT (median bias of 1.3%, range: –9.0% to 13.5%) while the overestimation of SUVmean with respect to orgCT was

  16. Seismic attenuation structure in central Mexico: Image of a focused high-attenuation zone in the mantle wedge

    OpenAIRE

    Chen, Ting; Clayton, Robert W.

    2009-01-01

    Velocity spectra from moderate-sized earthquakes were used to investigate the P wave attenuation structure in central Mexico. In particular, we included regional events with magnitudes in the range of 4.5 to 6.1 recorded from 2005 to 2007 on the Middle American Subduction Experiment (MASE) array, which consists of 100 broadband sensors across central Mexico from Acapulco to Tempoal, near the Gulf of Mexico. By assuming a Brune-type source, a frequency-independent t* value was obtained for eac...

  17. (-)-Epicatechin Attenuates Degradation of Mouse Oxidative Muscle Following Hindlimb Suspension.

    Science.gov (United States)

    Lee, Icksoo; Hüttemann, Maik; Malek, Moh H

    2016-01-01

    The purpose of this study was to conduct a 14-day hindlimb suspension (HS) with and without (-)-epicatechin supplementation to determine whether (-)-epicatechin treatment can attenuate the loss in muscle degradation, angiogenesis, and mitochondrial signaling in oxidative skeletal muscle. Adult mice were randomized into 3 groups: (a) control (C); (b) HS with vehicle (HS-V); and (c) HS with (-)-epicatechin (HS-(-)-Epi). Animals in the HS-(-)-Epi group received (-)-epicatechin (1.0 mg · kg(-1) of body mass) twice daily through oral gavage. For markers related to muscle degradation, the HS-V group had significantly higher protein expression compared with the control and HS-(-)-Epi groups. Moreover, protein expression for myosin heavy chain type I was significantly reduced by approximately 45% in the HS-V group compared with the control and HS-(-)-Epi groups. In addition, capillarity contact and capillary-to-fiber ratio were significantly higher in the HS-(-)-Epi group compared with the HS-V group. Furthermore, protein expression for thrombospondin-1 was significantly higher in HS-V group compared with the control and HS-(-)-Epi groups. Hindlimb suspension also significantly reduced protein expression for mitochondrial signaling compared with the control and HS-(-)-Epi groups. These findings suggest that (-)-epicatechin supplementation attenuates degradation in oxidative muscles after HS.

  18. Attenuation of cryocooler induced vibration in spaceborne infrared payloads

    Science.gov (United States)

    Veprik, A.; Twitto, A.

    2014-01-01

    Recent advancement of operational responsive space programs calls for a development of compact, reliable, low power and vibration free cryogenic cooling for sophisticated infrared payloads. The refrigeration in a typical closed cycle split Stirling linear cryocooler is achieved by a cyclic compression and expansion of a gaseous working agent due to a synchronized reciprocation of electro-dynamically and pneumatically actuated compressor and expander pistons. Attenuation of the cryocooler induced vibration usually relies on the concept of actively assisted momentum cancellation. In a typical dual-piston compressor this objective is achieved by actively synchronizing the motion of oppositely moving piston assemblies; a typical single-piston expander may be counterbalanced by a motorized counter-balancer. The above approach produces complexity, weight, size, high incurred costs and affects reliability. The authors analyze the case of passive attenuation the vibration export induced by the split Stirling linear cryocooler comprised of inline mounted single-piston compressor and expander. Placement of all the moving components onto a common axis results in a single axis consolidation of vibration export and enables use of single tuned dynamic absorber and low frequency vibration mount. From theoretical analysis and full-scale testing, the performance of such vibration protection arrangement is similar to known systems of active vibration cancellation.

  19. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice.

    Directory of Open Access Journals (Sweden)

    Seung Jun Lee

    Full Text Available Radiation-induced lung injury (RILI is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day. Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis.

  20. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice.

    Science.gov (United States)

    Lee, Seung Jun; Yi, Chin-ok; Heo, Rok Won; Song, Dae Hyun; Cho, Yu Ji; Jeong, Yi Yeong; Kang, Ki Mun; Roh, Gu Seob; Lee, Jong Deog

    2015-01-01

    Radiation-induced lung injury (RILI) is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA) to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day). Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF)-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis. PMID:26114656

  1. Seismic attenuation due to wave-induced flow

    Energy Technology Data Exchange (ETDEWEB)

    Pride, S.R.; Berryman, J.G.; Harris, J.M.

    2003-10-09

    Analytical expressions for three P-wave attenuation mechanisms in sedimentary rocks are given a unified theoretical framework. Two of the models concern wave-induced flow due to heterogeneity in the elastic moduli at mesoscopic scales (scales greater than grain sizes but smaller than wavelengths). In the first model, the heterogeneity is due to lithological variations (e.g., mixtures of sands and clays) with a single fluid saturating all the pores. In the second model, a single uniform lithology is saturated in mesoscopic ''patches'' by two immiscible fluids (e.g., air and water). In the third model, the heterogeneity is at ''microscopic'' grain scales (broken grain contacts and/or micro-cracks in the grains) and the associated fluid response corresponds to ''squirt flow''. The model of squirt flow derived here reduces to proper limits as any of the fluid bulk modulus, crack porosity, and/or frequency is reduced to zero. It is shown that squirt flow is incapable of explaining the measured level of loss (10{sup -2} < Q{sup -1} < 10{sup -1}) within the seismic band of frequencies (1 to 10{sup 4} Hz); however, either of the two mesoscopic scale models easily produce enough attenuation to explain the field data.

  2. Attenuation coefficient of usable solar radiation of the global oceans

    Science.gov (United States)

    Lin, Junfang; Lee, Zhongping; Ondrusek, Michael; Kahru, Mati

    2016-05-01

    Usable solar radiation (USR) represents spectrally integrated solar energy in the spectral range of 400-560 nm, a domain where photons penetrate the most in oceanic waters and thus contribute to photosynthesis and heating at deeper depths. Through purely numerical simulations, it was found that the diffuse attenuation coefficient of downwelling USR (Kd(USR), m-1) is nearly a constant vertically in the upper water column for clear waters and most turbid waters. Subsequently an empirical model was developed to estimate Kd(USR) based on the diffuse attenuation coefficient at 490 nm (Kd(490), m-1). We here evaluate this relationship using data collected from a wide range of oceanic and coastal environments and found that the relationship between Kd(490) and Kd(USR) developed via the numerical simulation is quite robust. We further refined this relationship to extend the applicability to "clearest" natural waters. This refined relationship was then used to produce sample distribution of Kd(USR) of global oceans. As expected, extremely low Kd(USR) (˜0.02 m-1) was observed in ocean gyres, while significantly higher Kd(USR) (˜5.2 m-1) was found in very turbid coastal regions. A useful application of Kd(USR) is to easily and accurately propagate surface USR to deeper depths, potentially to significantly improve the estimation of basin scale primary production and heat fluxes in the upper water column.

  3. Tracking the attenuation and nonbreaking dissipation of swells using altimeters

    Science.gov (United States)

    Jiang, Haoyu; Stopa, Justin E.; Wang, He; Husson, Romain; Mouche, Alexis; Chapron, Bertrand; Chen, Ge

    2016-02-01

    A method for systematically tracking swells across oceanic basins is developed by taking advantage of high-quality data from space-borne altimeters and wave model output. The evolution of swells is observed over large distances based on 202 swell events with periods ranging from 12 to 18 s. An empirical attenuation rate of swell energy of about 4 × 10-7 m-1 is estimated using these observations, and the nonbreaking energy dissipation rates of swells far away from their generating areas are also estimated using a point source model. The resulting acceptance range of nonbreaking dissipation rates is -2.5 to 5.0 × 10-7 m-1, which corresponds to a dissipation e-folding scales of at least 2000 km for steep swells, to almost infinite for small-amplitude swells. These resulting rates are consistent with previous studies using in-situ and synthetic aperture radar (SAR) observations. The frequency dispersion and angular spreading effects during swell propagation are discussed by comparing the results with other studies, demonstrating that they are the two dominant processes for swell height attenuation, especially in the near field. The resulting dissipation rates from these observations can be used as a reference for ocean engineering and wave modeling, and for related studies such as air-sea and wind-wave-turbulence interactions.

  4. Arctigenin attenuates lipopolysaccharide-induced acute lung injury in rats.

    Science.gov (United States)

    Shi, Xianbao; Sun, Hongzhi; Zhou, Dun; Xi, Huanjiu; Shan, Lina

    2015-04-01

    Arctigenin (ATG) has been reported to possess anti-inflammatory properties. However, the effects of ATG on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains not well understood. In the present study, our investigation was designed to reveal the effect of ATG on LPS-induced ALI in rats. We found that ATG pretreatment attenuated the LPS-induced ALI, as evidenced by the reduced histological scores, myeloperoxidase activity, and wet-to-dry weight ratio in the lung tissues. This was accompanied by the decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-1 (IL-6) in the bronchoalveolar lavage fluid. Furthermore, ATG downregulated the expression of nuclear factor kappa B (NF-κB) p65, promoted the phosphorylation of inhibitor of nuclear factor-κB-α (IκBα) and activated the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPKα) in the lung tissues. Our results suggested that ATG attenuates the LPS-induced ALI via activation of AMPK and suppression of NF-κB signaling pathway. PMID:25008149

  5. Arctigenin attenuates lipopolysaccharide-induced acute lung injury in rats.

    Science.gov (United States)

    Shi, Xianbao; Sun, Hongzhi; Zhou, Dun; Xi, Huanjiu; Shan, Lina

    2015-04-01

    Arctigenin (ATG) has been reported to possess anti-inflammatory properties. However, the effects of ATG on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains not well understood. In the present study, our investigation was designed to reveal the effect of ATG on LPS-induced ALI in rats. We found that ATG pretreatment attenuated the LPS-induced ALI, as evidenced by the reduced histological scores, myeloperoxidase activity, and wet-to-dry weight ratio in the lung tissues. This was accompanied by the decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-1 (IL-6) in the bronchoalveolar lavage fluid. Furthermore, ATG downregulated the expression of nuclear factor kappa B (NF-κB) p65, promoted the phosphorylation of inhibitor of nuclear factor-κB-α (IκBα) and activated the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPKα) in the lung tissues. Our results suggested that ATG attenuates the LPS-induced ALI via activation of AMPK and suppression of NF-κB signaling pathway.

  6. Flame attenuation effects on surface temperature measurements using IR thermography

    Science.gov (United States)

    de Vries, Jaap; Tabinowski, Robert

    2016-05-01

    Long-wave infrared (LWIR) cameras provide the unique ability to see through smoke and condensed water vapor. However, soot generated inside the flame does attenuate the LWIR signal. This work focuses on gas flame attenuation effects of LWIR signals originating from a blackbody. The experimental setup consists of time averaged, laboratory-scale turbulent diffusion flames with heat release rates set at 5 kW, 10 kW, and 15 kW. Propylene and ethylene were used as fuel, providing two different soot yields. A 30 cm by 30 cm blackbody was used with maximum surface temperatures set to 600°C. Both instantaneous and time-averaged blackbody temperature profiles through the flame were measured using a LWIR microbolometer camera (7.5-14 μm). Flame intermittency was quantified by color segmenting visible images. The experiments showed that low blackbody temperatures were significantly affected by the presence of the flame. At 600°C, the effect of flame absorption matches the emitted radiation from the flame itself. Using data obtained at various blackbody temperatures, the flame transmittance was obtained using a Generalized Reduced Gradient optimization method. The transmittance was lower for propylene flames compared to ethylene flames. Ethylene flames were shown to have higher temperatures. Using the values for flame radiance and transmissivity, the total averaged radiance of the flame plus the blackbody could be reproduced with 1% accuracy.

  7. The role of mangroves in attenuating storm surges

    Science.gov (United States)

    Zhang, Keqi; Liu, Huiqing; Li, Yuepeng; Xu, Hongzhou; Shen, Jian; Rhome, Jamie; Smith, J.

    2012-01-01

    Field observations and numerical simulations indicate that the 6-to-30-km-wide mangrove forest along the Gulf Coast of South Florida effectively attenuated stormsurges from a Category 3 hurricane, Wilma, and protected the inland wetland by reducing an inundation area of 1800 km2 and restricting surge inundation inside the mangrove zone. The surge amplitude decreases at a rate of 40–50 cm/km across the mangrove forest and at a rate of 20 cm/km across the areas with a mixture of mangrove islands with open water. In contrast, the amplitudes of stormsurges at the front of the mangrove zone increase by about 10–30% because of the "blockage" of mangroves to surge water, which can cause greater impacts on structures at the front of mangroves than the case without mangroves. The mangrove forest can also protect the wetlands behind the mangrove zone against surge inundation from a Category 5 hurricane with a fast forward speed of 11.2 m/s (25 mph). However, the forest cannot fully attenuate stormsurges from a Category 5 hurricane with a slow forward speed of 2.2 m/s (5 mph) and reduced surges can still affect the wetlands behind the mangrove zone. The effects of widths of mangrove zones on reducing surge amplitudes are nonlinear with large reduction rates (15–30%) for initial width increments and small rates (<5%) for subsequent width increments.

  8. Functional analysis and evaluation of waste repositories using attenuation factors

    International Nuclear Information System (INIS)

    This is the first of three articles on the development of standards for geologic disposal of radioactive waste presented in this issue of Radioactive Waste Management and Environmental Restoration. Knowledge of how entire disposal systems will function is needed before they can be regulated effectively. This article describes the operation of terrestrial and subseabed geologic repositories, and presents an evaluation procedure that can be used to supply information needed to develop standards and regulations, evaluate repository concepts, and compute design requirements of specific repository systems. The attenuation factor method of evaluation was developed based on spatial and temporal dispersion, retardation, and dilution processes. This method computes the reduction of risk potential made by each component of the system. Mathematical models for deterministic and probabilistic analyses along with several examples are given. Uses and limitations of the method are discussed. Although the attenuation factor method was developed for the disposal of radioactive waste, it can be adapted to the disposal of nonradioactive hazardous wastes. The second article presents the functional requirements of geologic repositories, defines the functions and hierarchy of repository standards, and suggests procedures for developing the standards. The third article develops original standards for nuclear waste disposal processes not covered by the existing regulations, such as subseabed disposal, and evaluates proposed alternatives to modify the existing nuclear waste disposal standards for terrestrial repositories. (author) 7 figs., 2 tabs., 19 refs

  9. Northern California Seismic Attenuation: 3-D Qp and Qs models

    Science.gov (United States)

    Eberhart-Phillips, D. M.

    2015-12-01

    The northern California crust exhibits a wide range of rock types and deformation processes which produce pronounced heterogeneity in regional attenuation. Using local earthquakes, 3-D Qp and Qs crustal models have been obtained for this region which includes the San Andreas fault system, the Central Valley, the Sierra Nevada batholith, and the Mendocino subduction volcanic system. Path attenuation t* values were determined from P and S spectra of 959 spatially distributed earthquakes, magnitude 2.5-6.0 from 2005-2014, using 1254 stations from NCEDC networks and IRIS Mendocino and Sierra Nevada temporary arrays. The t* data were used in Q inversions, using existing hypocenters and 3-D velocity models, with basic 10-km node spacing. The uneven data coverage was accounted for with linking of nodes into larger areas in order to provide useful Q images across the 3-D volume. The results at shallow depth (< 2 km) show very low Q in the Sacramento Delta, the Eureka area, and parts of the Bay Area. In the brittle crust, fault zones that have high seismicity exhibit low Q. In the lower crust, low Q is observed along fault zones that have large cumulative displacement and have experienced grain size reduction. Underlying active volcanic areas, low Q features are apparent below 20-km depth. Moderately high Q is associated with igneous rocks of the Sierra Nevada and Salinian block, while the Franciscan subduction complex shows moderately low Q. The most prominent high Q feature is related to the Great Valley Ophiolite.

  10. Galacto-oligosaccharides attenuate renal injury with microbiota modification.

    Science.gov (United States)

    Furuse, Satoshi U; Ohse, Takamoto; Jo-Watanabe, Airi; Shigehisa, Akira; Kawakami, Koji; Matsuki, Takahiro; Chonan, Osamu; Nangaku, Masaomi

    2014-07-01

    Tubulointerstitial injury is central to the progression of end-stage renal disease. Recent studies have revealed that one of the most investigated uremic toxins, indoxyl sulfate (IS), caused tubulointerstitial injury through oxidative stress and endoplasmic reticulum (ER) stress. Because indole, the precursor of IS, is synthesized from dietary tryptophan by the gut microbiota, we hypothesized that the intervention targeting the gut microbiota in kidney disease with galacto-oligosaccharides (GOS) would attenuate renal injury. After 2 weeks of GOS administration for 5/6 nephrectomized (Nx) or sham-operated (Sham) rats, cecal indole and serum IS were measured, renal injury was evaluated, and the effects of GOS on the gut microbiota were examined using pyrosequencing methods. Cecal indole and serum IS were significantly decreased and renal injury was improved with decreased infiltrating macrophages in GOS-treated Nx rats. The expression levels of ER stress markers and apoptosis were significantly increased in the Nx rats and decreased with GOS. The microbiota analysis indicated that GOS significantly increased three bacterial families and decreased five families in the Nx rats. In addition, the analysis also revealed that the bacterial family Clostridiaceae was significantly increased in the Nx rats compared with the Sham rats and decreased with GOS. Taken altogether, our data show that GOS decreased cecal indole and serum IS, attenuated renal injury, and modified the gut microbiota in the Nx rats, and that the gut microbiota were altered in kidney disease. GOS could be a novel therapeutic agent to protect against renal injury.

  11. Review of methods to attenuate shock/blast waves

    Science.gov (United States)

    Igra, O.; Falcovitz, J.; Houas, L.; Jourdan, G.

    2013-04-01

    Quick and reliable shock wave attenuation is the goal of every protection facility and therefore it is not surprising that achieving this has drawn much attention during the past hundred years. Different options have been suggested; their usefulness varying from a reasonable protection to the opposite, a shock enhancement. An example for a suggestion for shock mitigation that turned out to be an enhancement of the impinging shock wave was the idea to cover a protected object with a foam layer. While the pressure behind the reflected shock wave from the foam frontal surface was smaller than that recorded in a similar reflection from a rigid wall [25], the pressure on the “protected” surface, attached to the foam's rear-surface, was significantly higher than that recorded in a similar reflection from a bare, rigid wall [11]. In protecting humans and installations from destructive shock and/or blast waves the prime goal is to reduce the wave amplitude and the rate of pressure increase across the wave front. Both measures result in reducing the wave harmful effects. During the past six decades several approaches for achieving the desired protection have been offered in the open literature. We point out in this review that while some of the suggestions offered are practical, others are impractical. In our discussion we focus on recent schemes for shock/blast wave attenuation, characterized by the availability of reliable measurements (notably pressure and optical diagnostics) as well as high-resolution numerical simulations.

  12. Photon counting spectroscopic CT with dynamic beam attenuator

    CERN Document Server

    Atak, Haluk

    2016-01-01

    Purpose: Photon counting (PC) computed tomography (CT) can provide material selective CT imaging at lowest patient dose but it suffers from suboptimal count rate. A dynamic beam attenuator (DBA) can help with count rate by modulating x-ray beam intensity such that the low attenuating areas of the patient receive lower exposure, and detector behind these areas is not overexposed. However, DBA may harden the beam and cause artifacts and errors. This work investigates positive and negative effects of using DBA in PCCT. Methods: A simple PCCT with single energy bin, spectroscopic PCCT with 2 and 5 energy bins, and conventional energy integrating CT with and without DBA were simulated and investigated using 120kVp tube voltage and 14mGy air dose. The DBAs were modeled as made from soft tissue (ST) equivalent material, iron (Fe), and holmium (Ho) K-edge material. A cylindrical CT phantom and chest phantom with iodine and CaCO3 contrast elements were used. Image artifacts and quantification errors in general and mat...

  13. Caspase-11 Modulates Inflammation and Attenuates Toxoplasma gondii Pathogenesis.

    Science.gov (United States)

    Coutermarsh-Ott, Sheryl L; Doran, John T; Campbell, Caroline; Williams, Tere M; Lindsay, David S; Allen, Irving C

    2016-01-01

    Toxoplasma gondii is an obligate intracellular parasite that is the etiologic agent responsible for toxoplasmosis. Infection with T. gondii results in activation of nucleotide binding domain and leucine rich repeat containing receptors (NLRs). NLR activation leads to inflammasome formation, the activation of caspase-1, and the subsequent cleavage of IL-1β and IL-18. Recently, a noncanonical inflammasome has been characterized which functions through caspase-11 and appears to augment many biological functions previously considered to be dependent upon the canonical inflammasome. To better elucidate the function of this noncanonical inflammasome in toxoplasmosis, we utilized Asc (-/-) and Casp11 (-/-) mice and infected these animals with T. gondii. Our data indicates that caspase-11 modulates the innate immune response to T. gondii through a mechanism which is distinct from that currently described for the canonical inflammasome. Asc (-/-) mice demonstrated increased disease pathogenesis during the acute phase of T. gondii infection, whereas Casp11 (-/-) mice demonstrated significantly attenuated disease pathogenesis and reduced inflammation. This attenuated host response was associated with reduced local and systemic cytokine production, including diminished IL-1β. During the chronic phase of infection, caspase-11 deficiency resulted in increased neuroinflammation and tissue cyst burden in the brain. Together, our data suggest that caspase-11 functions to protect the host by enhancing inflammation during the early phase of infection in an effort to minimize disease pathogenesis during later stages of toxoplasmosis. PMID:27378827

  14. Browning attenuates murine white adipose tissue expansion during postnatal development.

    Science.gov (United States)

    Lasar, D; Julius, A; Fromme, T; Klingenspor, M

    2013-05-01

    During postnatal development of mice distinct white adipose tissue depots display a transient appearance of brown-like adipocytes. These brite (brown in white) adipocytes share characteristics with classical brown adipocytes including a multilocular appearance and the expression of the thermogenic protein uncoupling protein 1. In this study, we compared two inbred mouse strains 129S6sv/ev and C57BL6/N known for their different propensity to diet-induced obesity. We observed transient browning in retroperitoneal and inguinal adipose tissue depots of these two strains. From postnatal day 10 to 20 the increase in the abundance of multilocular adipocytes and uncoupling protein 1 expression was higher in 129S6sv/ev than in C57BL6/N pups. The parallel increase in the mass of the two fat depots was attenuated during this browning period. Conversely, epididymal white and interscapular brown adipose tissue displayed a steady increase in mass during the first 30 days of life. In this period, 129S6sv/ev mice developed a significantly higher total body fat mass than C57BL6/N. Thus, while on a local depot level a high number of brite cells is associated with the attenuation of adipose tissue expansion the strain comparison reveals no support for a systemic impact on energy balance. This article is part of a Special Issue entitled Brown and White Fat: From Signaling to Disease.

  15. Nitrite attenuated peroxynitrite and hypochlorite generation in activated neutrophils.

    Science.gov (United States)

    Ren, Xiaoming; Ding, Yun; Lu, Naihao

    2016-03-15

    Oxidative stress is usually considered as an important factor to the pathogenesis of various diseases. Peroxynitrite (ONOO(-)) and hypochlorite (OCl(-)) are formed in immune cells as a part of the innate host defense system, but excessive reactive oxygen species generation can cause progressive inflammation and tissue damage. It has been proven that through mediating nitric oxide (NO) homeostasis, inorganic nitrite (NO2(-)) shows organ-protective effects on oxidative stress and inflammation. However, the effects of NO2(-) on the function of immune cells were still not clear. The potential role of NO2(-) in modulating ONOO(-) and OCl(-) generation in neutrophil cells was investigated in this study. As an immune cell activator, lipopolysaccharide (LPS) increased both ONOO(-) and OCl(-) production in neutrophils, which was significantly attenuated by NO2(-). NO2(-) reduced superoxide (O2(·-)) generation via a NO-dependent mechanism and increased NO formation in activated neutrophils, suggesting a crucial role of O2(·-) in NO2(-)-mediated reduction of ONOO(-). Moreover, the reduced effect of NO2(-) on OCl(-) production was attributed to that NO2(-) reduced H2O2 production in activated neutrophils without influencing the release of myeloperoxidase (MPO), thus limiting OCl(-) production by MPO/H2O2 system. Therefore, NO2(-) attenuates ONOO(-) and OCl(-) formation in activated neutrophils, opening a new direction to modulate the inflammatory response. PMID:26854590

  16. R-flurbiprofen attenuates experimental autoimmune encephalomyelitis in mice.

    Science.gov (United States)

    Schmitz, Katja; de Bruin, Natasja; Bishay, Philipp; Männich, Julia; Häussler, Annett; Altmann, Christine; Ferreirós, Nerea; Lötsch, Jörn; Ultsch, Alfred; Parnham, Michael J; Geisslinger, Gerd; Tegeder, Irmgard

    2014-11-01

    R-flurbiprofen is the non-cyclooxygenase inhibiting R-enantiomer of the non-steroidal anti-inflammatory drug flurbiprofen, which was assessed as a remedy for Alzheimer's disease. Because of its anti-inflammatory, endocannabinoid-modulating and antioxidative properties, combined with low toxicity, the present study assessed R-flurbiprofen in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis in mice. Oral R-flurbiprofen prevented and attenuated primary progressive EAE in C57BL6/J mice and relapsing-remitting EAE in SJL mice, even if the treatment was initiated on or after the first flare of the disease. R-flurbiprofen reduced immune cell infiltration and microglia activation and inflammation in the spinal cord, brain and optic nerve and attenuated myelin destruction and EAE-evoked hyperalgesia. R-flurbiprofen treatment increased CD4(+)CD25(+)FoxP3(+) regulatory T cells, CTLA4(+) inhibitory T cells and interleukin-10, whereas the EAE-evoked upregulation of pro-inflammatory genes in the spinal cord was strongly reduced. The effects were associated with an increase of plasma and cortical endocannabinoids but decreased spinal prostaglandins, the latter likely due to R to S inversion. The promising results suggest potential efficacy of R-flurbiprofen in human MS, and its low toxicity may justify a clinical trial.

  17. Recruitment-of-loudness effects of attenuative noise reduction algorithms

    Science.gov (United States)

    Whitmal, Nathaniel; Vosoughi, Azadeh

    2002-05-01

    Hearing-impaired listeners have greater difficulty understanding speech in noise than normal-hearing listeners do. As a result, hearing aid users are often challenged by the inability of their hearing aids to improve intelligibility in noise. Several investigators have addressed this problem by using well-known signal processing methods (e.g., spectral subtraction, Wiener filtering) to enhance noise-corrupted speech. Unfortunately, these methods have failed to provide significant improvements in intelligibility. One possible explanation is the level-dependent nature of the attenuation that the algorithms impose on the speech. In the cases described above, this attenuation resembles the piecewise-linear input-output characteristic observed in certain recruitment-of-loudness simulators. The purpose of this study was to compare the intelligibility of processed speech with that expected for recruitment-of-loudness simulation. Trials of the CUNY Nonsense Syllable Test were conducted with 12 normal-hearing listeners, using syllables that were mixed with additive noise at SNRs of 6, 12, and 18 dB. Input-output characteristics for the signals were measured and used to determine the effective threshold shift imposed by the algorithms. Comparisons of measured intelligibility scores with articulation index-based intelligibility predictions indicate that the behavior of such noise reduction algorithms can be successfully modeled as a form of mild sensorineural hearing loss.

  18. Mechanical spectroscopy, internal friction and ultrasonic attenuation: Collection of works

    International Nuclear Information System (INIS)

    An extensive collection of recommended books and proceedings from numerous conferences on internal friction, mechanical spectroscopy, and ultrasonic attenuation is provided. Reflecting the complicated history of the 20th century, books published in English and in Russian are presented in two separate sections. International and national conferences organized in various countries are listed. Supplementary lists referring to conferences held in the People's Republic of China, Poland, Russia, the Soviet Union, and Ukraine are also provided. The interesting evolution of mechanical spectroscopy from internal friction and ultrasonic attenuation in solids is clearly demonstrated, and a choice list of retrospective papers illustrates the evolution of the field. A brief review of mechanical spectroscopy, therefore, is included. Numerous research areas investigated by internal friction and mechanical spectroscopy are addressed, including point defect relaxations, electronic and phonon relaxations, dislocation relaxations, grain boundary relaxations, domain induced relaxations (magnetic, ferroelectric), magnetomechanical relaxations, phase transformations, glass transitions, interface effects as well as a wide array of applications specific to physics and materials science. For many years now, there has been a definite need to provide a thorough list of references that might cover major national conferences and books published in English and other languages. This work strives to achieve this goal.

  19. Extragalactic Background Light and Gamma-Ray Attenuation

    CERN Document Server

    Primack, Joel R; Gilmore, Rudy C; Somerville, Rachel S

    2011-01-01

    Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits from observed galaxies. These upper limits now rule out some EBL models and purported observations, with improved data likely to provide even stronger constraints. We present EBL calculations both based on multiwavelength observations of thousands of galaxies and also based on semi-analytic models, and show that they are consistent with these lower limits from observed galaxies and with the gamma-ray upper limit constraints. Such comparisons "close the loop" on cosmological galaxy formation models, since they account for all the light, including that from galaxies too faint to see. We compare our results with those of other recent works, and discuss the implications of these new EBL calculations for gamma ray attenuation. Catching a few GRBs with groundbased atmospheric Cher...

  20. Mechanical compression attenuates normal human bronchial epithelial wound healing

    Directory of Open Access Journals (Sweden)

    Malavia Nikita

    2009-02-01

    Full Text Available Abstract Background Airway narrowing associated with chronic asthma results in the transmission of injurious compressive forces to the bronchial epithelium and promotes the release of pro-inflammatory mediators and the denudation of the bronchial epithelium. While the individual effects of compression or denudation are well characterized, there is no data to elucidate how these cells respond to the application of mechanical compression in the presence of a compromised epithelial layer. Methods Accordingly, differentiated normal human bronchial epithelial cells were exposed to one of four conditions: 1 unperturbed control cells, 2 single scrape wound only, 3 static compression (6 hours of 30 cmH2O, and 4 6 hours of static compression after a scrape wound. Following treatment, wound closure rate was recorded, media was assayed for mediator content and the cytoskeletal network was fluorescently labeled. Results We found that mechanical compression and scrape injury increase TGF-β2 and endothelin-1 secretion, while EGF content in the media is attenuated with both injury modes. The application of compression after a pre-existing scrape wound augmented these observations, and also decreased PGE2 media content. Compression stimulated depolymerization of the actin cytoskeleton and significantly attenuated wound healing. Closure rate was partially restored with the addition of exogenous PGE2, but not EGF. Conclusion Our results suggest that mechanical compression reduces the capacity of the bronchial epithelium to close wounds, and is, in part, mediated by PGE2 and a compromised cytoskeleton.